drivers/scsi/st.c

   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2016 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20160209";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/slab.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/cdrom.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/delay.h>
  42 #include <linux/mutex.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <asm/dma.h>
  46
  47 #include <scsi/scsi.h>
  48 #include <scsi/scsi_dbg.h>
  49 #include <scsi/scsi_device.h>
  50 #include <scsi/scsi_driver.h>
  51 #include <scsi/scsi_eh.h>
  52 #include <scsi/scsi_host.h>
  53 #include <scsi/scsi_ioctl.h>
  54 #include <scsi/sg.h>
  55
  56
  57 /* The driver prints some debugging information on the console if DEBUG
  58    is defined and non-zero. */
  59 #define DEBUG 1
  60 #define NO_DEBUG 0
  61
  62 #define ST_DEB_MSG  KERN_NOTICE
  63 #if DEBUG
  64 /* The message level for the debug messages is currently set to KERN_NOTICE
  65    so that people can easily see the messages. Later when the debugging messages
  66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67 #define DEB(a) a
  68 #define DEBC(a) if (debugging) { a ; }
  69 #else
  70 #define DEB(a)
  71 #define DEBC(a)
  72 #endif
  73
  74 #define ST_KILOBYTE 1024
  75
  76 #include "st_options.h"
  77 #include "st.h"
  78
  79 static int buffer_kbs;
  80 static int max_sg_segs;
  81 static int try_direct_io = TRY_DIRECT_IO;
  82 static int try_rdio = 1;
  83 static int try_wdio = 1;
  84 static int debug_flag;
  85
  86 static struct class st_sysfs_class;
  87 static const struct attribute_group *st_dev_groups[];
  88 static const struct attribute_group *st_drv_groups[];
  89
  90 MODULE_AUTHOR("Kai Makisara");
  91 MODULE_DESCRIPTION("SCSI tape (st) driver");
  92 MODULE_LICENSE("GPL");
  93 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97  * of sysfs parameters (which module_param doesn't yet support).
  98  * Sysfs parameters defined explicitly later.
  99  */
 100 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104 module_param_named(try_direct_io, try_direct_io, int, 0);
 105 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106 module_param_named(debug_flag, debug_flag, int, 0);
 107 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110 /* Extra parameters for testing */
 111 module_param_named(try_rdio, try_rdio, int, 0);
 112 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113 module_param_named(try_wdio, try_wdio, int, 0);
 114 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116 #ifndef MODULE
 117 static int write_threshold_kbs;  /* retained for compatibility */
 118 static struct st_dev_parm {
 119         char *name;
 120         int *val;
 121 } parms[] __initdata = {
 122         {
 123                 "buffer_kbs", &buffer_kbs
 124         },
 125         {       /* Retained for compatibility with 2.4 */
 126                 "write_threshold_kbs", &write_threshold_kbs
 127         },
 128         {
 129                 "max_sg_segs", NULL
 130         },
 131         {
 132                 "try_direct_io", &try_direct_io
 133         },
 134         {
 135                 "debug_flag", &debug_flag
 136         }
 137 };
 138 #endif
 139
 140 /* Restrict the number of modes so that names for all are assigned */
 141 #if ST_NBR_MODES > 16
 142 #error "Maximum number of modes is 16"
 143 #endif
 144 /* Bit reversed order to get same names for same minors with all
 145    mode counts */
 146 static const char *st_formats[] = {
 147         "",  "r", "k", "s", "l", "t", "o", "u",
 148         "m", "v", "p", "x", "a", "y", "q", "z"};
 149
 150 /* The default definitions have been moved to st_options.h */
 151
 152 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154 /* The buffer size should fit into the 24 bits for length in the
 155    6-byte SCSI read and write commands. */
 156 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158 #endif
 159
 160 static int debugging = DEBUG;
 161
 162 #define MAX_RETRIES 0
 163 #define MAX_WRITE_RETRIES 0
 164 #define MAX_READY_RETRIES 0
 165 #define NO_TAPE  NOT_READY
 166
 167 #define ST_TIMEOUT (900 * HZ)
 168 #define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170 /* Remove mode bits and auto-rewind bit (7) */
 171 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180    24 bits) */
 181 #define SET_DENS_AND_BLK 0x10001
 182
 183 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184 static int st_max_sg_segs = ST_MAX_SG;
 185
 186 static int modes_defined;
 187
 188 static int enlarge_buffer(struct st_buffer *, int, int);
 189 static void clear_buffer(struct st_buffer *);
 190 static void normalize_buffer(struct st_buffer *);
 191 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192 static int from_buffer(struct st_buffer *, char __user *, int);
 193 static void move_buffer_data(struct st_buffer *, int);
 194
 195 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196                               unsigned long, size_t, int);
 197 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199 static int st_probe(struct device *);
 200 static int st_remove(struct device *);
 201
 202 static struct scsi_driver st_template = {
 203         .gendrv = {
 204                 .name           = "st",
 205                 .owner          = THIS_MODULE,
 206                 .probe          = st_probe,
 207                 .remove         = st_remove,
 208                 .groups         = st_drv_groups,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224 static DEFINE_SPINLOCK(st_index_lock);
 225 static DEFINE_SPINLOCK(st_use_lock);
 226 static DEFINE_IDR(st_index_idr);
 227
 228
 229 \f
 230 #include "osst_detect.h"
 231 #ifndef SIGS_FROM_OSST
 232 #define SIGS_FROM_OSST \
 233         {"OnStream", "SC-", "", "osst"}, \
 234         {"OnStream", "DI-", "", "osst"}, \
 235         {"OnStream", "DP-", "", "osst"}, \
 236         {"OnStream", "USB", "", "osst"}, \
 237         {"OnStream", "FW-", "", "osst"}
 238 #endif
 239
 240 static struct scsi_tape *scsi_tape_get(int dev)
 241 {
 242         struct scsi_tape *STp = NULL;
 243
 244         mutex_lock(&st_ref_mutex);
 245         spin_lock(&st_index_lock);
 246
 247         STp = idr_find(&st_index_idr, dev);
 248         if (!STp) goto out;
 249
 250         kref_get(&STp->kref);
 251
 252         if (!STp->device)
 253                 goto out_put;
 254
 255         if (scsi_device_get(STp->device))
 256                 goto out_put;
 257
 258         goto out;
 259
 260 out_put:
 261         kref_put(&STp->kref, scsi_tape_release);
 262         STp = NULL;
 263 out:
 264         spin_unlock(&st_index_lock);
 265         mutex_unlock(&st_ref_mutex);
 266         return STp;
 267 }
 268
 269 static void scsi_tape_put(struct scsi_tape *STp)
 270 {
 271         struct scsi_device *sdev = STp->device;
 272
 273         mutex_lock(&st_ref_mutex);
 274         kref_put(&STp->kref, scsi_tape_release);
 275         scsi_device_put(sdev);
 276         mutex_unlock(&st_ref_mutex);
 277 }
 278
 279 struct st_reject_data {
 280         char *vendor;
 281         char *model;
 282         char *rev;
 283         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284 };
 285
 286 static struct st_reject_data reject_list[] = {
 287         /* {"XXX", "Yy-", "", NULL},  example */
 288         SIGS_FROM_OSST,
 289         {NULL, }};
 290
 291 /* If the device signature is on the list of incompatible drives, the
 292    function returns a pointer to the name of the correct driver (if known) */
 293 static char * st_incompatible(struct scsi_device* SDp)
 294 {
 295         struct st_reject_data *rp;
 296
 297         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301                         if (rp->driver_hint)
 302                                 return rp->driver_hint;
 303                         else
 304                                 return "unknown";
 305                 }
 306         return NULL;
 307 }
 308 \f
 309
 310 static inline char *tape_name(struct scsi_tape *tape)
 311 {
 312         return tape->disk->disk_name;
 313 }
 314
 315 #define st_printk(prefix, t, fmt, a...) \
 316         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317 #ifdef DEBUG
 318 #define DEBC_printk(t, fmt, a...) \
 319         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320 #else
 321 #define DEBC_printk(t, fmt, a...)
 322 #endif
 323
 324 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325 {
 326         const u8 *ucp;
 327         const u8 *sense = SRpnt->sense;
 328
 329         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331         s->flags = 0;
 332
 333         if (s->have_sense) {
 334                 s->deferred = 0;
 335                 s->remainder_valid =
 336                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337                 switch (sense[0] & 0x7f) {
 338                 case 0x71:
 339                         s->deferred = 1;
 340                 case 0x70:
 341                         s->fixed_format = 1;
 342                         s->flags = sense[2] & 0xe0;
 343                         break;
 344                 case 0x73:
 345                         s->deferred = 1;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = tape_name(STp);
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390                                result, driver_byte(result), host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         ktime_t now;
 476
 477         now = ktime_get();
 478         if (req->cmd[0] == WRITE_6) {
 479                 now = ktime_sub(now, STp->stats->write_time);
 480                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482                 atomic64_inc(&STp->stats->write_cnt);
 483                 if (req->errors) {
 484                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 485                                 - STp->buffer->cmdstat.residual,
 486                                 &STp->stats->write_byte_cnt);
 487                         if (STp->buffer->cmdstat.residual > 0)
 488                                 atomic64_inc(&STp->stats->resid_cnt);
 489                 } else
 490                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 491                                 &STp->stats->write_byte_cnt);
 492         } else if (req->cmd[0] == READ_6) {
 493                 now = ktime_sub(now, STp->stats->read_time);
 494                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496                 atomic64_inc(&STp->stats->read_cnt);
 497                 if (req->errors) {
 498                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 499                                 - STp->buffer->cmdstat.residual,
 500                                 &STp->stats->read_byte_cnt);
 501                         if (STp->buffer->cmdstat.residual > 0)
 502                                 atomic64_inc(&STp->stats->resid_cnt);
 503                 } else
 504                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 505                                 &STp->stats->read_byte_cnt);
 506         } else {
 507                 now = ktime_sub(now, STp->stats->other_time);
 508                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509                 atomic64_inc(&STp->stats->other_cnt);
 510         }
 511         atomic64_dec(&STp->stats->in_flight);
 512 }
 513
 514 static void st_scsi_execute_end(struct request *req, int uptodate)
 515 {
 516         struct st_request *SRpnt = req->end_io_data;
 517         struct scsi_tape *STp = SRpnt->stp;
 518         struct bio *tmp;
 519
 520         STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
 521         STp->buffer->cmdstat.residual = req->resid_len;
 522
 523         st_do_stats(STp, req);
 524
 525         tmp = SRpnt->bio;
 526         if (SRpnt->waiting)
 527                 complete(SRpnt->waiting);
 528
 529         blk_rq_unmap_user(tmp);
 530         __blk_put_request(req->q, req);
 531 }
 532
 533 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 534                            int data_direction, void *buffer, unsigned bufflen,
 535                            int timeout, int retries)
 536 {
 537         struct request *req;
 538         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 539         int err = 0;
 540         int write = (data_direction == DMA_TO_DEVICE);
 541         struct scsi_tape *STp = SRpnt->stp;
 542
 543         req = blk_get_request(SRpnt->stp->device->request_queue, write,
 544                               GFP_KERNEL);
 545         if (IS_ERR(req))
 546                 return DRIVER_ERROR << 24;
 547
 548         blk_rq_set_block_pc(req);
 549         req->cmd_flags |= REQ_QUIET;
 550
 551         mdata->null_mapped = 1;
 552
 553         if (bufflen) {
 554                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 555                                       GFP_KERNEL);
 556                 if (err) {
 557                         blk_put_request(req);
 558                         return DRIVER_ERROR << 24;
 559                 }
 560         }
 561
 562         atomic64_inc(&STp->stats->in_flight);
 563         if (cmd[0] == WRITE_6) {
 564                 atomic_set(&STp->stats->last_write_size, bufflen);
 565                 STp->stats->write_time = ktime_get();
 566         } else if (cmd[0] == READ_6) {
 567                 atomic_set(&STp->stats->last_read_size, bufflen);
 568                 STp->stats->read_time = ktime_get();
 569         } else {
 570                 STp->stats->other_time = ktime_get();
 571         }
 572
 573         SRpnt->bio = req->bio;
 574         req->cmd_len = COMMAND_SIZE(cmd[0]);
 575         memset(req->cmd, 0, BLK_MAX_CDB);
 576         memcpy(req->cmd, cmd, req->cmd_len);
 577         req->sense = SRpnt->sense;
 578         req->sense_len = 0;
 579         req->timeout = timeout;
 580         req->retries = retries;
 581         req->end_io_data = SRpnt;
 582
 583         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 584         return 0;
 585 }
 586
 587 /* Do the scsi command. Waits until command performed if do_wait is true.
 588    Otherwise write_behind_check() is used to check that the command
 589    has finished. */
 590 static struct st_request *
 591 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 592            int bytes, int direction, int timeout, int retries, int do_wait)
 593 {
 594         struct completion *waiting;
 595         struct rq_map_data *mdata = &STp->buffer->map_data;
 596         int ret;
 597
 598         /* if async, make sure there's no command outstanding */
 599         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 600                 st_printk(KERN_ERR, STp,
 601                           "Async command already active.\n");
 602                 if (signal_pending(current))
 603                         (STp->buffer)->syscall_result = (-EINTR);
 604                 else
 605                         (STp->buffer)->syscall_result = (-EBUSY);
 606                 return NULL;
 607         }
 608
 609         if (!SRpnt) {
 610                 SRpnt = st_allocate_request(STp);
 611                 if (!SRpnt)
 612                         return NULL;
 613         }
 614
 615         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 616            which IO is outstanding. It's nulled out when the IO completes. */
 617         if (!do_wait)
 618                 (STp->buffer)->last_SRpnt = SRpnt;
 619
 620         waiting = &STp->wait;
 621         init_completion(waiting);
 622         SRpnt->waiting = waiting;
 623
 624         if (STp->buffer->do_dio) {
 625                 mdata->page_order = 0;
 626                 mdata->nr_entries = STp->buffer->sg_segs;
 627                 mdata->pages = STp->buffer->mapped_pages;
 628         } else {
 629                 mdata->page_order = STp->buffer->reserved_page_order;
 630                 mdata->nr_entries =
 631                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 632                 mdata->pages = STp->buffer->reserved_pages;
 633                 mdata->offset = 0;
 634         }
 635
 636         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 637         STp->buffer->cmdstat.have_sense = 0;
 638         STp->buffer->syscall_result = 0;
 639
 640         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 641                               retries);
 642         if (ret) {
 643                 /* could not allocate the buffer or request was too large */
 644                 (STp->buffer)->syscall_result = (-EBUSY);
 645                 (STp->buffer)->last_SRpnt = NULL;
 646         } else if (do_wait) {
 647                 wait_for_completion(waiting);
 648                 SRpnt->waiting = NULL;
 649                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 650         }
 651
 652         return SRpnt;
 653 }
 654
 655
 656 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 657    write has been correct but EOM early warning reached, -EIO if write ended in
 658    error or zero if write successful. Asynchronous writes are used only in
 659    variable block mode. */
 660 static int write_behind_check(struct scsi_tape * STp)
 661 {
 662         int retval = 0;
 663         struct st_buffer *STbuffer;
 664         struct st_partstat *STps;
 665         struct st_cmdstatus *cmdstatp;
 666         struct st_request *SRpnt;
 667
 668         STbuffer = STp->buffer;
 669         if (!STbuffer->writing)
 670                 return 0;
 671
 672         DEB(
 673         if (STp->write_pending)
 674                 STp->nbr_waits++;
 675         else
 676                 STp->nbr_finished++;
 677         ) /* end DEB */
 678
 679         wait_for_completion(&(STp->wait));
 680         SRpnt = STbuffer->last_SRpnt;
 681         STbuffer->last_SRpnt = NULL;
 682         SRpnt->waiting = NULL;
 683
 684         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 685         st_release_request(SRpnt);
 686
 687         STbuffer->buffer_bytes -= STbuffer->writing;
 688         STps = &(STp->ps[STp->partition]);
 689         if (STps->drv_block >= 0) {
 690                 if (STp->block_size == 0)
 691                         STps->drv_block++;
 692                 else
 693                         STps->drv_block += STbuffer->writing / STp->block_size;
 694         }
 695
 696         cmdstatp = &STbuffer->cmdstat;
 697         if (STbuffer->syscall_result) {
 698                 retval = -EIO;
 699                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 700                     (cmdstatp->flags & SENSE_EOM) &&
 701                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 702                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 703                         /* EOM at write-behind, has all data been written? */
 704                         if (!cmdstatp->remainder_valid ||
 705                             cmdstatp->uremainder64 == 0)
 706                                 retval = -ENOSPC;
 707                 }
 708                 if (retval == -EIO)
 709                         STps->drv_block = -1;
 710         }
 711         STbuffer->writing = 0;
 712
 713         DEB(if (debugging && retval)
 714                     st_printk(ST_DEB_MSG, STp,
 715                                 "Async write error %x, return value %d.\n",
 716                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 717
 718         return retval;
 719 }
 720
 721
 722 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 723    it messes up the block number). */
 724 static int cross_eof(struct scsi_tape * STp, int forward)
 725 {
 726         struct st_request *SRpnt;
 727         unsigned char cmd[MAX_COMMAND_SIZE];
 728
 729         cmd[0] = SPACE;
 730         cmd[1] = 0x01;          /* Space FileMarks */
 731         if (forward) {
 732                 cmd[2] = cmd[3] = 0;
 733                 cmd[4] = 1;
 734         } else
 735                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 736         cmd[5] = 0;
 737
 738         DEBC_printk(STp, "Stepping over filemark %s.\n",
 739                     forward ? "forward" : "backward");
 740
 741         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 742                            STp->device->request_queue->rq_timeout,
 743                            MAX_RETRIES, 1);
 744         if (!SRpnt)
 745                 return (STp->buffer)->syscall_result;
 746
 747         st_release_request(SRpnt);
 748         SRpnt = NULL;
 749
 750         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 751                 st_printk(KERN_ERR, STp,
 752                           "Stepping over filemark %s failed.\n",
 753                           forward ? "forward" : "backward");
 754
 755         return (STp->buffer)->syscall_result;
 756 }
 757
 758
 759 /* Flush the write buffer (never need to write if variable blocksize). */
 760 static int st_flush_write_buffer(struct scsi_tape * STp)
 761 {
 762         int transfer, blks;
 763         int result;
 764         unsigned char cmd[MAX_COMMAND_SIZE];
 765         struct st_request *SRpnt;
 766         struct st_partstat *STps;
 767
 768         result = write_behind_check(STp);
 769         if (result)
 770                 return result;
 771
 772         result = 0;
 773         if (STp->dirty == 1) {
 774
 775                 transfer = STp->buffer->buffer_bytes;
 776                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 777
 778                 memset(cmd, 0, MAX_COMMAND_SIZE);
 779                 cmd[0] = WRITE_6;
 780                 cmd[1] = 1;
 781                 blks = transfer / STp->block_size;
 782                 cmd[2] = blks >> 16;
 783                 cmd[3] = blks >> 8;
 784                 cmd[4] = blks;
 785
 786                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 787                                    STp->device->request_queue->rq_timeout,
 788                                    MAX_WRITE_RETRIES, 1);
 789                 if (!SRpnt)
 790                         return (STp->buffer)->syscall_result;
 791
 792                 STps = &(STp->ps[STp->partition]);
 793                 if ((STp->buffer)->syscall_result != 0) {
 794                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 795
 796                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 797                             (cmdstatp->flags & SENSE_EOM) &&
 798                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 799                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 800                             (!cmdstatp->remainder_valid ||
 801                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 802                                 STp->dirty = 0;
 803                                 (STp->buffer)->buffer_bytes = 0;
 804                                 if (STps->drv_block >= 0)
 805                                         STps->drv_block += blks;
 806                                 result = (-ENOSPC);
 807                         } else {
 808                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 809                                 STps->drv_block = (-1);
 810                                 result = (-EIO);
 811                         }
 812                 } else {
 813                         if (STps->drv_block >= 0)
 814                                 STps->drv_block += blks;
 815                         STp->dirty = 0;
 816                         (STp->buffer)->buffer_bytes = 0;
 817                 }
 818                 st_release_request(SRpnt);
 819                 SRpnt = NULL;
 820         }
 821         return result;
 822 }
 823
 824
 825 /* Flush the tape buffer. The tape will be positioned correctly unless
 826    seek_next is true. */
 827 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 828 {
 829         int backspace, result;
 830         struct st_buffer *STbuffer;
 831         struct st_partstat *STps;
 832
 833         STbuffer = STp->buffer;
 834
 835         /*
 836          * If there was a bus reset, block further access
 837          * to this device.
 838          */
 839         if (STp->pos_unknown)
 840                 return (-EIO);
 841
 842         if (STp->ready != ST_READY)
 843                 return 0;
 844         STps = &(STp->ps[STp->partition]);
 845         if (STps->rw == ST_WRITING)     /* Writing */
 846                 return st_flush_write_buffer(STp);
 847
 848         if (STp->block_size == 0)
 849                 return 0;
 850
 851         backspace = ((STp->buffer)->buffer_bytes +
 852                      (STp->buffer)->read_pointer) / STp->block_size -
 853             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 854             STp->block_size;
 855         (STp->buffer)->buffer_bytes = 0;
 856         (STp->buffer)->read_pointer = 0;
 857         result = 0;
 858         if (!seek_next) {
 859                 if (STps->eof == ST_FM_HIT) {
 860                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 861                         if (!result)
 862                                 STps->eof = ST_NOEOF;
 863                         else {
 864                                 if (STps->drv_file >= 0)
 865                                         STps->drv_file++;
 866                                 STps->drv_block = 0;
 867                         }
 868                 }
 869                 if (!result && backspace > 0)
 870                         result = st_int_ioctl(STp, MTBSR, backspace);
 871         } else if (STps->eof == ST_FM_HIT) {
 872                 if (STps->drv_file >= 0)
 873                         STps->drv_file++;
 874                 STps->drv_block = 0;
 875                 STps->eof = ST_NOEOF;
 876         }
 877         return result;
 878
 879 }
 880 \f
 881 /* Set the mode parameters */
 882 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 883 {
 884         int set_it = 0;
 885         unsigned long arg;
 886
 887         if (!STp->density_changed &&
 888             STm->default_density >= 0 &&
 889             STm->default_density != STp->density) {
 890                 arg = STm->default_density;
 891                 set_it = 1;
 892         } else
 893                 arg = STp->density;
 894         arg <<= MT_ST_DENSITY_SHIFT;
 895         if (!STp->blksize_changed &&
 896             STm->default_blksize >= 0 &&
 897             STm->default_blksize != STp->block_size) {
 898                 arg |= STm->default_blksize;
 899                 set_it = 1;
 900         } else
 901                 arg |= STp->block_size;
 902         if (set_it &&
 903             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 904                 st_printk(KERN_WARNING, STp,
 905                           "Can't set default block size to %d bytes "
 906                           "and density %x.\n",
 907                           STm->default_blksize, STm->default_density);
 908                 if (modes_defined)
 909                         return (-EINVAL);
 910         }
 911         return 0;
 912 }
 913
 914
 915 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 916 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 917 {
 918         int retval;
 919
 920         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 921
 922         retval = scsi_set_medium_removal(STp->device,
 923                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 924         if (!retval)
 925                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 926         else
 927                 STp->door_locked = ST_LOCK_FAILS;
 928         return retval;
 929 }
 930
 931
 932 /* Set the internal state after reset */
 933 static void reset_state(struct scsi_tape *STp)
 934 {
 935         int i;
 936         struct st_partstat *STps;
 937
 938         STp->pos_unknown = 0;
 939         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 940                 STps = &(STp->ps[i]);
 941                 STps->rw = ST_IDLE;
 942                 STps->eof = ST_NOEOF;
 943                 STps->at_sm = 0;
 944                 STps->last_block_valid = 0;
 945                 STps->drv_block = -1;
 946                 STps->drv_file = -1;
 947         }
 948         if (STp->can_partitions) {
 949                 STp->partition = find_partition(STp);
 950                 if (STp->partition < 0)
 951                         STp->partition = 0;
 952                 STp->new_partition = STp->partition;
 953         }
 954 }
 955 \f
 956 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 957    error code. */
 958 #define CHKRES_READY       0
 959 #define CHKRES_NEW_SESSION 1
 960 #define CHKRES_NOT_READY   2
 961 #define CHKRES_NO_TAPE     3
 962
 963 #define MAX_ATTENTIONS    10
 964
 965 static int test_ready(struct scsi_tape *STp, int do_wait)
 966 {
 967         int attentions, waits, max_wait, scode;
 968         int retval = CHKRES_READY, new_session = 0;
 969         unsigned char cmd[MAX_COMMAND_SIZE];
 970         struct st_request *SRpnt = NULL;
 971         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 972
 973         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 974
 975         for (attentions=waits=0; ; ) {
 976                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 977                 cmd[0] = TEST_UNIT_READY;
 978                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 979                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 980
 981                 if (!SRpnt) {
 982                         retval = (STp->buffer)->syscall_result;
 983                         break;
 984                 }
 985
 986                 if (cmdstatp->have_sense) {
 987
 988                         scode = cmdstatp->sense_hdr.sense_key;
 989
 990                         if (scode == UNIT_ATTENTION) { /* New media? */
 991                                 new_session = 1;
 992                                 if (attentions < MAX_ATTENTIONS) {
 993                                         attentions++;
 994                                         continue;
 995                                 }
 996                                 else {
 997                                         retval = (-EIO);
 998                                         break;
 999                                 }
1000                         }
1001
1002                         if (scode == NOT_READY) {
1003                                 if (waits < max_wait) {
1004                                         if (msleep_interruptible(1000)) {
1005                                                 retval = (-EINTR);
1006                                                 break;
1007                                         }
1008                                         waits++;
1009                                         continue;
1010                                 }
1011                                 else {
1012                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1013                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1014                                                 retval = CHKRES_NO_TAPE;
1015                                         else
1016                                                 retval = CHKRES_NOT_READY;
1017                                         break;
1018                                 }
1019                         }
1020                 }
1021
1022                 retval = (STp->buffer)->syscall_result;
1023                 if (!retval)
1024                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1025                 break;
1026         }
1027
1028         if (SRpnt != NULL)
1029                 st_release_request(SRpnt);
1030         return retval;
1031 }
1032
1033
1034 /* See if the drive is ready and gather information about the tape. Return values:
1035    < 0   negative error code from errno.h
1036    0     drive ready
1037    1     drive not ready (possibly no tape)
1038 */
1039 static int check_tape(struct scsi_tape *STp, struct file *filp)
1040 {
1041         int i, retval, new_session = 0, do_wait;
1042         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1043         unsigned short st_flags = filp->f_flags;
1044         struct st_request *SRpnt = NULL;
1045         struct st_modedef *STm;
1046         struct st_partstat *STps;
1047         struct inode *inode = file_inode(filp);
1048         int mode = TAPE_MODE(inode);
1049
1050         STp->ready = ST_READY;
1051
1052         if (mode != STp->current_mode) {
1053                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1054                             STp->current_mode, mode);
1055                 new_session = 1;
1056                 STp->current_mode = mode;
1057         }
1058         STm = &(STp->modes[STp->current_mode]);
1059
1060         saved_cleaning = STp->cleaning_req;
1061         STp->cleaning_req = 0;
1062
1063         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1064         retval = test_ready(STp, do_wait);
1065
1066         if (retval < 0)
1067             goto err_out;
1068
1069         if (retval == CHKRES_NEW_SESSION) {
1070                 STp->pos_unknown = 0;
1071                 STp->partition = STp->new_partition = 0;
1072                 if (STp->can_partitions)
1073                         STp->nbr_partitions = 1; /* This guess will be updated later
1074                                                     if necessary */
1075                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1076                         STps = &(STp->ps[i]);
1077                         STps->rw = ST_IDLE;
1078                         STps->eof = ST_NOEOF;
1079                         STps->at_sm = 0;
1080                         STps->last_block_valid = 0;
1081                         STps->drv_block = 0;
1082                         STps->drv_file = 0;
1083                 }
1084                 new_session = 1;
1085         }
1086         else {
1087                 STp->cleaning_req |= saved_cleaning;
1088
1089                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1090                         if (retval == CHKRES_NO_TAPE)
1091                                 STp->ready = ST_NO_TAPE;
1092                         else
1093                                 STp->ready = ST_NOT_READY;
1094
1095                         STp->density = 0;       /* Clear the erroneous "residue" */
1096                         STp->write_prot = 0;
1097                         STp->block_size = 0;
1098                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1099                         STp->partition = STp->new_partition = 0;
1100                         STp->door_locked = ST_UNLOCKED;
1101                         return CHKRES_NOT_READY;
1102                 }
1103         }
1104
1105         if (STp->omit_blklims)
1106                 STp->min_block = STp->max_block = (-1);
1107         else {
1108                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1109                 cmd[0] = READ_BLOCK_LIMITS;
1110
1111                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1112                                    STp->device->request_queue->rq_timeout,
1113                                    MAX_READY_RETRIES, 1);
1114                 if (!SRpnt) {
1115                         retval = (STp->buffer)->syscall_result;
1116                         goto err_out;
1117                 }
1118
1119                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1120                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1121                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1122                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1123                             (STp->buffer)->b_data[5];
1124                         if ( DEB( debugging || ) !STp->inited)
1125                                 st_printk(KERN_INFO, STp,
1126                                           "Block limits %d - %d bytes.\n",
1127                                           STp->min_block, STp->max_block);
1128                 } else {
1129                         STp->min_block = STp->max_block = (-1);
1130                         DEBC_printk(STp, "Can't read block limits.\n");
1131                 }
1132         }
1133
1134         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1135         cmd[0] = MODE_SENSE;
1136         cmd[4] = 12;
1137
1138         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1139                            STp->device->request_queue->rq_timeout,
1140                            MAX_READY_RETRIES, 1);
1141         if (!SRpnt) {
1142                 retval = (STp->buffer)->syscall_result;
1143                 goto err_out;
1144         }
1145
1146         if ((STp->buffer)->syscall_result != 0) {
1147                 DEBC_printk(STp, "No Mode Sense.\n");
1148                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1149                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1150                 STp->drv_write_prot = 0;
1151         } else {
1152                 DEBC_printk(STp,"Mode sense. Length %d, "
1153                             "medium %x, WBS %x, BLL %d\n",
1154                             (STp->buffer)->b_data[0],
1155                             (STp->buffer)->b_data[1],
1156                             (STp->buffer)->b_data[2],
1157                             (STp->buffer)->b_data[3]);
1158
1159                 if ((STp->buffer)->b_data[3] >= 8) {
1160                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1161                         STp->density = (STp->buffer)->b_data[4];
1162                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1163                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1164                         DEBC_printk(STp, "Density %x, tape length: %x, "
1165                                     "drv buffer: %d\n",
1166                                     STp->density,
1167                                     (STp->buffer)->b_data[5] * 65536 +
1168                                     (STp->buffer)->b_data[6] * 256 +
1169                                     (STp->buffer)->b_data[7],
1170                                     STp->drv_buffer);
1171                 }
1172                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1173                 if (!STp->drv_buffer && STp->immediate_filemark) {
1174                         st_printk(KERN_WARNING, STp,
1175                                   "non-buffered tape: disabling "
1176                                   "writing immediate filemarks\n");
1177                         STp->immediate_filemark = 0;
1178                 }
1179         }
1180         st_release_request(SRpnt);
1181         SRpnt = NULL;
1182         STp->inited = 1;
1183
1184         if (STp->block_size > 0)
1185                 (STp->buffer)->buffer_blocks =
1186                         (STp->buffer)->buffer_size / STp->block_size;
1187         else
1188                 (STp->buffer)->buffer_blocks = 1;
1189         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1190
1191         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1192                     STp->block_size, (STp->buffer)->buffer_size,
1193                     (STp->buffer)->buffer_blocks);
1194
1195         if (STp->drv_write_prot) {
1196                 STp->write_prot = 1;
1197
1198                 DEBC_printk(STp, "Write protected\n");
1199
1200                 if (do_wait &&
1201                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1202                      (st_flags & O_ACCMODE) == O_RDWR)) {
1203                         retval = (-EROFS);
1204                         goto err_out;
1205                 }
1206         }
1207
1208         if (STp->can_partitions && STp->nbr_partitions < 1) {
1209                 /* This code is reached when the device is opened for the first time
1210                    after the driver has been initialized with tape in the drive and the
1211                    partition support has been enabled. */
1212                 DEBC_printk(STp, "Updating partition number in status.\n");
1213                 if ((STp->partition = find_partition(STp)) < 0) {
1214                         retval = STp->partition;
1215                         goto err_out;
1216                 }
1217                 STp->new_partition = STp->partition;
1218                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1219         }
1220
1221         if (new_session) {      /* Change the drive parameters for the new mode */
1222                 STp->density_changed = STp->blksize_changed = 0;
1223                 STp->compression_changed = 0;
1224                 if (!(STm->defaults_for_writes) &&
1225                     (retval = set_mode_densblk(STp, STm)) < 0)
1226                     goto err_out;
1227
1228                 if (STp->default_drvbuffer != 0xff) {
1229                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1230                                 st_printk(KERN_WARNING, STp,
1231                                           "Can't set default drive "
1232                                           "buffering to %d.\n",
1233                                           STp->default_drvbuffer);
1234                 }
1235         }
1236
1237         return CHKRES_READY;
1238
1239  err_out:
1240         return retval;
1241 }
1242
1243
1244 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1245    module count. */
1246 static int st_open(struct inode *inode, struct file *filp)
1247 {
1248         int i, retval = (-EIO);
1249         int resumed = 0;
1250         struct scsi_tape *STp;
1251         struct st_partstat *STps;
1252         int dev = TAPE_NR(inode);
1253
1254         /*
1255          * We really want to do nonseekable_open(inode, filp); here, but some
1256          * versions of tar incorrectly call lseek on tapes and bail out if that
1257          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1258          */
1259         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1260
1261         if (!(STp = scsi_tape_get(dev))) {
1262                 return -ENXIO;
1263         }
1264
1265         filp->private_data = STp;
1266
1267         spin_lock(&st_use_lock);
1268         if (STp->in_use) {
1269                 spin_unlock(&st_use_lock);
1270                 scsi_tape_put(STp);
1271                 DEBC_printk(STp, "Device already in use.\n");
1272                 return (-EBUSY);
1273         }
1274
1275         STp->in_use = 1;
1276         spin_unlock(&st_use_lock);
1277         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1278
1279         if (scsi_autopm_get_device(STp->device) < 0) {
1280                 retval = -EIO;
1281                 goto err_out;
1282         }
1283         resumed = 1;
1284         if (!scsi_block_when_processing_errors(STp->device)) {
1285                 retval = (-ENXIO);
1286                 goto err_out;
1287         }
1288
1289         /* See that we have at least a one page buffer available */
1290         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1291                 st_printk(KERN_WARNING, STp,
1292                           "Can't allocate one page tape buffer.\n");
1293                 retval = (-EOVERFLOW);
1294                 goto err_out;
1295         }
1296
1297         (STp->buffer)->cleared = 0;
1298         (STp->buffer)->writing = 0;
1299         (STp->buffer)->syscall_result = 0;
1300
1301         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1302
1303         STp->dirty = 0;
1304         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1305                 STps = &(STp->ps[i]);
1306                 STps->rw = ST_IDLE;
1307         }
1308         STp->try_dio_now = STp->try_dio;
1309         STp->recover_count = 0;
1310         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1311              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1312
1313         retval = check_tape(STp, filp);
1314         if (retval < 0)
1315                 goto err_out;
1316         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1317             retval != CHKRES_READY) {
1318                 if (STp->ready == NO_TAPE)
1319                         retval = (-ENOMEDIUM);
1320                 else
1321                         retval = (-EIO);
1322                 goto err_out;
1323         }
1324         return 0;
1325
1326  err_out:
1327         normalize_buffer(STp->buffer);
1328         spin_lock(&st_use_lock);
1329         STp->in_use = 0;
1330         spin_unlock(&st_use_lock);
1331         if (resumed)
1332                 scsi_autopm_put_device(STp->device);
1333         scsi_tape_put(STp);
1334         return retval;
1335
1336 }
1337 \f
1338
1339 /* Flush the tape buffer before close */
1340 static int st_flush(struct file *filp, fl_owner_t id)
1341 {
1342         int result = 0, result2;
1343         unsigned char cmd[MAX_COMMAND_SIZE];
1344         struct st_request *SRpnt;
1345         struct scsi_tape *STp = filp->private_data;
1346         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1347         struct st_partstat *STps = &(STp->ps[STp->partition]);
1348
1349         if (file_count(filp) > 1)
1350                 return 0;
1351
1352         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1353                 result = st_flush_write_buffer(STp);
1354                 if (result != 0 && result != (-ENOSPC))
1355                         goto out;
1356         }
1357
1358         if (STp->can_partitions &&
1359             (result2 = switch_partition(STp)) < 0) {
1360                 DEBC_printk(STp, "switch_partition at close failed.\n");
1361                 if (result == 0)
1362                         result = result2;
1363                 goto out;
1364         }
1365
1366         DEBC( if (STp->nbr_requests)
1367                 st_printk(KERN_DEBUG, STp,
1368                           "Number of r/w requests %d, dio used in %d, "
1369                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1370                           STp->nbr_pages));
1371
1372         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1373                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1374
1375 #if DEBUG
1376                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1377                             STp->nbr_waits, STp->nbr_finished);
1378 #endif
1379                 memset(cmd, 0, MAX_COMMAND_SIZE);
1380                 cmd[0] = WRITE_FILEMARKS;
1381                 if (STp->immediate_filemark)
1382                         cmd[1] = 1;
1383                 cmd[4] = 1 + STp->two_fm;
1384
1385                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1386                                    STp->device->request_queue->rq_timeout,
1387                                    MAX_WRITE_RETRIES, 1);
1388                 if (!SRpnt) {
1389                         result = (STp->buffer)->syscall_result;
1390                         goto out;
1391                 }
1392
1393                 if (STp->buffer->syscall_result == 0 ||
1394                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1395                      (cmdstatp->flags & SENSE_EOM) &&
1396                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1397                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1398                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1399                         /* Write successful at EOM */
1400                         st_release_request(SRpnt);
1401                         SRpnt = NULL;
1402                         if (STps->drv_file >= 0)
1403                                 STps->drv_file++;
1404                         STps->drv_block = 0;
1405                         if (STp->two_fm)
1406                                 cross_eof(STp, 0);
1407                         STps->eof = ST_FM;
1408                 }
1409                 else { /* Write error */
1410                         st_release_request(SRpnt);
1411                         SRpnt = NULL;
1412                         st_printk(KERN_ERR, STp,
1413                                   "Error on write filemark.\n");
1414                         if (result == 0)
1415                                 result = (-EIO);
1416                 }
1417
1418                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1419         } else if (!STp->rew_at_close) {
1420                 STps = &(STp->ps[STp->partition]);
1421                 if (!STm->sysv || STps->rw != ST_READING) {
1422                         if (STp->can_bsr)
1423                                 result = flush_buffer(STp, 0);
1424                         else if (STps->eof == ST_FM_HIT) {
1425                                 result = cross_eof(STp, 0);
1426                                 if (result) {
1427                                         if (STps->drv_file >= 0)
1428                                                 STps->drv_file++;
1429                                         STps->drv_block = 0;
1430                                         STps->eof = ST_FM;
1431                                 } else
1432                                         STps->eof = ST_NOEOF;
1433                         }
1434                 } else if ((STps->eof == ST_NOEOF &&
1435                             !(result = cross_eof(STp, 1))) ||
1436                            STps->eof == ST_FM_HIT) {
1437                         if (STps->drv_file >= 0)
1438                                 STps->drv_file++;
1439                         STps->drv_block = 0;
1440                         STps->eof = ST_FM;
1441                 }
1442         }
1443
1444       out:
1445         if (STp->rew_at_close) {
1446                 result2 = st_int_ioctl(STp, MTREW, 1);
1447                 if (result == 0)
1448                         result = result2;
1449         }
1450         return result;
1451 }
1452
1453
1454 /* Close the device and release it. BKL is not needed: this is the only thread
1455    accessing this tape. */
1456 static int st_release(struct inode *inode, struct file *filp)
1457 {
1458         int result = 0;
1459         struct scsi_tape *STp = filp->private_data;
1460
1461         if (STp->door_locked == ST_LOCKED_AUTO)
1462                 do_door_lock(STp, 0);
1463
1464         normalize_buffer(STp->buffer);
1465         spin_lock(&st_use_lock);
1466         STp->in_use = 0;
1467         spin_unlock(&st_use_lock);
1468         scsi_autopm_put_device(STp->device);
1469         scsi_tape_put(STp);
1470
1471         return result;
1472 }
1473 \f
1474 /* The checks common to both reading and writing */
1475 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1476 {
1477         ssize_t retval = 0;
1478
1479         /*
1480          * If we are in the middle of error recovery, don't let anyone
1481          * else try and use this device.  Also, if error recovery fails, it
1482          * may try and take the device offline, in which case all further
1483          * access to the device is prohibited.
1484          */
1485         if (!scsi_block_when_processing_errors(STp->device)) {
1486                 retval = (-ENXIO);
1487                 goto out;
1488         }
1489
1490         if (STp->ready != ST_READY) {
1491                 if (STp->ready == ST_NO_TAPE)
1492                         retval = (-ENOMEDIUM);
1493                 else
1494                         retval = (-EIO);
1495                 goto out;
1496         }
1497
1498         if (! STp->modes[STp->current_mode].defined) {
1499                 retval = (-ENXIO);
1500                 goto out;
1501         }
1502
1503
1504         /*
1505          * If there was a bus reset, block further access
1506          * to this device.
1507          */
1508         if (STp->pos_unknown) {
1509                 retval = (-EIO);
1510                 goto out;
1511         }
1512
1513         if (count == 0)
1514                 goto out;
1515
1516         DEB(
1517         if (!STp->in_use) {
1518                 st_printk(ST_DEB_MSG, STp,
1519                           "Incorrect device.\n");
1520                 retval = (-EIO);
1521                 goto out;
1522         } ) /* end DEB */
1523
1524         if (STp->can_partitions &&
1525             (retval = switch_partition(STp)) < 0)
1526                 goto out;
1527
1528         if (STp->block_size == 0 && STp->max_block > 0 &&
1529             (count < STp->min_block || count > STp->max_block)) {
1530                 retval = (-EINVAL);
1531                 goto out;
1532         }
1533
1534         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1535             !do_door_lock(STp, 1))
1536                 STp->door_locked = ST_LOCKED_AUTO;
1537
1538  out:
1539         return retval;
1540 }
1541
1542
1543 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1544                            size_t count, int is_read)
1545 {
1546         int i, bufsize, retval = 0;
1547         struct st_buffer *STbp = STp->buffer;
1548
1549         if (is_read)
1550                 i = STp->try_dio_now && try_rdio;
1551         else
1552                 i = STp->try_dio_now && try_wdio;
1553
1554         if (i && ((unsigned long)buf & queue_dma_alignment(
1555                                         STp->device->request_queue)) == 0) {
1556                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1557                                        count, (is_read ? READ : WRITE));
1558                 if (i > 0) {
1559                         STbp->do_dio = i;
1560                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1561                 }
1562                 else
1563                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1564                 STbp->sg_segs = STbp->do_dio;
1565                 DEB(
1566                      if (STbp->do_dio) {
1567                         STp->nbr_dio++;
1568                         STp->nbr_pages += STbp->do_dio;
1569                      }
1570                 )
1571         } else
1572                 STbp->do_dio = 0;
1573         DEB( STp->nbr_requests++; )
1574
1575         if (!STbp->do_dio) {
1576                 if (STp->block_size)
1577                         bufsize = STp->block_size > st_fixed_buffer_size ?
1578                                 STp->block_size : st_fixed_buffer_size;
1579                 else {
1580                         bufsize = count;
1581                         /* Make sure that data from previous user is not leaked even if
1582                            HBA does not return correct residual */
1583                         if (is_read && STp->sili && !STbp->cleared)
1584                                 clear_buffer(STbp);
1585                 }
1586
1587                 if (bufsize > STbp->buffer_size &&
1588                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1589                         st_printk(KERN_WARNING, STp,
1590                                   "Can't allocate %d byte tape buffer.\n",
1591                                   bufsize);
1592                         retval = (-EOVERFLOW);
1593                         goto out;
1594                 }
1595                 if (STp->block_size)
1596                         STbp->buffer_blocks = bufsize / STp->block_size;
1597         }
1598
1599  out:
1600         return retval;
1601 }
1602
1603
1604 /* Can be called more than once after each setup_buffer() */
1605 static void release_buffering(struct scsi_tape *STp, int is_read)
1606 {
1607         struct st_buffer *STbp;
1608
1609         STbp = STp->buffer;
1610         if (STbp->do_dio) {
1611                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1612                 STbp->do_dio = 0;
1613                 STbp->sg_segs = 0;
1614         }
1615 }
1616
1617
1618 /* Write command */
1619 static ssize_t
1620 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1621 {
1622         ssize_t total;
1623         ssize_t i, do_count, blks, transfer;
1624         ssize_t retval;
1625         int undone, retry_eot = 0, scode;
1626         int async_write;
1627         unsigned char cmd[MAX_COMMAND_SIZE];
1628         const char __user *b_point;
1629         struct st_request *SRpnt = NULL;
1630         struct scsi_tape *STp = filp->private_data;
1631         struct st_modedef *STm;
1632         struct st_partstat *STps;
1633         struct st_buffer *STbp;
1634
1635         if (mutex_lock_interruptible(&STp->lock))
1636                 return -ERESTARTSYS;
1637
1638         retval = rw_checks(STp, filp, count);
1639         if (retval || count == 0)
1640                 goto out;
1641
1642         /* Write must be integral number of blocks */
1643         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1644                 st_printk(KERN_WARNING, STp,
1645                           "Write not multiple of tape block size.\n");
1646                 retval = (-EINVAL);
1647                 goto out;
1648         }
1649
1650         STm = &(STp->modes[STp->current_mode]);
1651         STps = &(STp->ps[STp->partition]);
1652
1653         if (STp->write_prot) {
1654                 retval = (-EACCES);
1655                 goto out;
1656         }
1657
1658
1659         if (STps->rw == ST_READING) {
1660                 retval = flush_buffer(STp, 0);
1661                 if (retval)
1662                         goto out;
1663                 STps->rw = ST_WRITING;
1664         } else if (STps->rw != ST_WRITING &&
1665                    STps->drv_file == 0 && STps->drv_block == 0) {
1666                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1667                         goto out;
1668                 if (STm->default_compression != ST_DONT_TOUCH &&
1669                     !(STp->compression_changed)) {
1670                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1671                                 st_printk(KERN_WARNING, STp,
1672                                           "Can't set default compression.\n");
1673                                 if (modes_defined) {
1674                                         retval = (-EINVAL);
1675                                         goto out;
1676                                 }
1677                         }
1678                 }
1679         }
1680
1681         STbp = STp->buffer;
1682         i = write_behind_check(STp);
1683         if (i) {
1684                 if (i == -ENOSPC)
1685                         STps->eof = ST_EOM_OK;
1686                 else
1687                         STps->eof = ST_EOM_ERROR;
1688         }
1689
1690         if (STps->eof == ST_EOM_OK) {
1691                 STps->eof = ST_EOD_1;  /* allow next write */
1692                 retval = (-ENOSPC);
1693                 goto out;
1694         }
1695         else if (STps->eof == ST_EOM_ERROR) {
1696                 retval = (-EIO);
1697                 goto out;
1698         }
1699
1700         /* Check the buffer readability in cases where copy_user might catch
1701            the problems after some tape movement. */
1702         if (STp->block_size != 0 &&
1703             !STbp->do_dio &&
1704             (copy_from_user(&i, buf, 1) != 0 ||
1705              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1706                 retval = (-EFAULT);
1707                 goto out;
1708         }
1709
1710         retval = setup_buffering(STp, buf, count, 0);
1711         if (retval)
1712                 goto out;
1713
1714         total = count;
1715
1716         memset(cmd, 0, MAX_COMMAND_SIZE);
1717         cmd[0] = WRITE_6;
1718         cmd[1] = (STp->block_size != 0);
1719
1720         STps->rw = ST_WRITING;
1721
1722         b_point = buf;
1723         while (count > 0 && !retry_eot) {
1724
1725                 if (STbp->do_dio) {
1726                         do_count = count;
1727                 }
1728                 else {
1729                         if (STp->block_size == 0)
1730                                 do_count = count;
1731                         else {
1732                                 do_count = STbp->buffer_blocks * STp->block_size -
1733                                         STbp->buffer_bytes;
1734                                 if (do_count > count)
1735                                         do_count = count;
1736                         }
1737
1738                         i = append_to_buffer(b_point, STbp, do_count);
1739                         if (i) {
1740                                 retval = i;
1741                                 goto out;
1742                         }
1743                 }
1744                 count -= do_count;
1745                 b_point += do_count;
1746
1747                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1748                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1749
1750                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1751                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1752                     STbp->buffer_bytes < STbp->buffer_size) {
1753                         STp->dirty = 1;
1754                         /* Don't write a buffer that is not full enough. */
1755                         if (!async_write && count == 0)
1756                                 break;
1757                 }
1758
1759         retry_write:
1760                 if (STp->block_size == 0)
1761                         blks = transfer = do_count;
1762                 else {
1763                         if (!STbp->do_dio)
1764                                 blks = STbp->buffer_bytes;
1765                         else
1766                                 blks = do_count;
1767                         blks /= STp->block_size;
1768                         transfer = blks * STp->block_size;
1769                 }
1770                 cmd[2] = blks >> 16;
1771                 cmd[3] = blks >> 8;
1772                 cmd[4] = blks;
1773
1774                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1775                                    STp->device->request_queue->rq_timeout,
1776                                    MAX_WRITE_RETRIES, !async_write);
1777                 if (!SRpnt) {
1778                         retval = STbp->syscall_result;
1779                         goto out;
1780                 }
1781                 if (async_write && !STbp->syscall_result) {
1782                         STbp->writing = transfer;
1783                         STp->dirty = !(STbp->writing ==
1784                                        STbp->buffer_bytes);
1785                         SRpnt = NULL;  /* Prevent releasing this request! */
1786                         DEB( STp->write_pending = 1; )
1787                         break;
1788                 }
1789
1790                 if (STbp->syscall_result != 0) {
1791                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1792
1793                         DEBC_printk(STp, "Error on write:\n");
1794                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1795                                 scode = cmdstatp->sense_hdr.sense_key;
1796                                 if (cmdstatp->remainder_valid)
1797                                         undone = (int)cmdstatp->uremainder64;
1798                                 else if (STp->block_size == 0 &&
1799                                          scode == VOLUME_OVERFLOW)
1800                                         undone = transfer;
1801                                 else
1802                                         undone = 0;
1803                                 if (STp->block_size != 0)
1804                                         undone *= STp->block_size;
1805                                 if (undone <= do_count) {
1806                                         /* Only data from this write is not written */
1807                                         count += undone;
1808                                         b_point -= undone;
1809                                         do_count -= undone;
1810                                         if (STp->block_size)
1811                                                 blks = (transfer - undone) / STp->block_size;
1812                                         STps->eof = ST_EOM_OK;
1813                                         /* Continue in fixed block mode if all written
1814                                            in this request but still something left to write
1815                                            (retval left to zero)
1816                                         */
1817                                         if (STp->block_size == 0 ||
1818                                             undone > 0 || count == 0)
1819                                                 retval = (-ENOSPC); /* EOM within current request */
1820                                         DEBC_printk(STp, "EOM with %d "
1821                                                     "bytes unwritten.\n",
1822                                                     (int)count);
1823                                 } else {
1824                                         /* EOT within data buffered earlier (possible only
1825                                            in fixed block mode without direct i/o) */
1826                                         if (!retry_eot && !cmdstatp->deferred &&
1827                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1828                                                 move_buffer_data(STp->buffer, transfer - undone);
1829                                                 retry_eot = 1;
1830                                                 if (STps->drv_block >= 0) {
1831                                                         STps->drv_block += (transfer - undone) /
1832                                                                 STp->block_size;
1833                                                 }
1834                                                 STps->eof = ST_EOM_OK;
1835                                                 DEBC_printk(STp, "Retry "
1836                                                             "write of %d "
1837                                                             "bytes at EOM.\n",
1838                                                             STp->buffer->buffer_bytes);
1839                                                 goto retry_write;
1840                                         }
1841                                         else {
1842                                                 /* Either error within data buffered by driver or
1843                                                    failed retry */
1844                                                 count -= do_count;
1845                                                 blks = do_count = 0;
1846                                                 STps->eof = ST_EOM_ERROR;
1847                                                 STps->drv_block = (-1); /* Too cautious? */
1848                                                 retval = (-EIO);        /* EOM for old data */
1849                                                 DEBC_printk(STp, "EOM with "
1850                                                             "lost data.\n");
1851                                         }
1852                                 }
1853                         } else {
1854                                 count += do_count;
1855                                 STps->drv_block = (-1);         /* Too cautious? */
1856                                 retval = STbp->syscall_result;
1857                         }
1858
1859                 }
1860
1861                 if (STps->drv_block >= 0) {
1862                         if (STp->block_size == 0)
1863                                 STps->drv_block += (do_count > 0);
1864                         else
1865                                 STps->drv_block += blks;
1866                 }
1867
1868                 STbp->buffer_bytes = 0;
1869                 STp->dirty = 0;
1870
1871                 if (retval || retry_eot) {
1872                         if (count < total)
1873                                 retval = total - count;
1874                         goto out;
1875                 }
1876         }
1877
1878         if (STps->eof == ST_EOD_1)
1879                 STps->eof = ST_EOM_OK;
1880         else if (STps->eof != ST_EOM_OK)
1881                 STps->eof = ST_NOEOF;
1882         retval = total - count;
1883
1884  out:
1885         if (SRpnt != NULL)
1886                 st_release_request(SRpnt);
1887         release_buffering(STp, 0);
1888         mutex_unlock(&STp->lock);
1889
1890         return retval;
1891 }
1892 \f
1893 /* Read data from the tape. Returns zero in the normal case, one if the
1894    eof status has changed, and the negative error code in case of a
1895    fatal error. Otherwise updates the buffer and the eof state.
1896
1897    Does release user buffer mapping if it is set.
1898 */
1899 static long read_tape(struct scsi_tape *STp, long count,
1900                       struct st_request ** aSRpnt)
1901 {
1902         int transfer, blks, bytes;
1903         unsigned char cmd[MAX_COMMAND_SIZE];
1904         struct st_request *SRpnt;
1905         struct st_modedef *STm;
1906         struct st_partstat *STps;
1907         struct st_buffer *STbp;
1908         int retval = 0;
1909
1910         if (count == 0)
1911                 return 0;
1912
1913         STm = &(STp->modes[STp->current_mode]);
1914         STps = &(STp->ps[STp->partition]);
1915         if (STps->eof == ST_FM_HIT)
1916                 return 1;
1917         STbp = STp->buffer;
1918
1919         if (STp->block_size == 0)
1920                 blks = bytes = count;
1921         else {
1922                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1923                         blks = (STp->buffer)->buffer_blocks;
1924                         bytes = blks * STp->block_size;
1925                 } else {
1926                         bytes = count;
1927                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1928                                 bytes = (STp->buffer)->buffer_size;
1929                         blks = bytes / STp->block_size;
1930                         bytes = blks * STp->block_size;
1931                 }
1932         }
1933
1934         memset(cmd, 0, MAX_COMMAND_SIZE);
1935         cmd[0] = READ_6;
1936         cmd[1] = (STp->block_size != 0);
1937         if (!cmd[1] && STp->sili)
1938                 cmd[1] |= 2;
1939         cmd[2] = blks >> 16;
1940         cmd[3] = blks >> 8;
1941         cmd[4] = blks;
1942
1943         SRpnt = *aSRpnt;
1944         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1945                            STp->device->request_queue->rq_timeout,
1946                            MAX_RETRIES, 1);
1947         release_buffering(STp, 1);
1948         *aSRpnt = SRpnt;
1949         if (!SRpnt)
1950                 return STbp->syscall_result;
1951
1952         STbp->read_pointer = 0;
1953         STps->at_sm = 0;
1954
1955         /* Something to check */
1956         if (STbp->syscall_result) {
1957                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1958
1959                 retval = 1;
1960                 DEBC_printk(STp,
1961                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1962                             SRpnt->sense[0], SRpnt->sense[1],
1963                             SRpnt->sense[2], SRpnt->sense[3],
1964                             SRpnt->sense[4], SRpnt->sense[5],
1965                             SRpnt->sense[6], SRpnt->sense[7]);
1966                 if (cmdstatp->have_sense) {
1967
1968                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1969                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1970
1971                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1972                                 /* Compute the residual count */
1973                                 if (cmdstatp->remainder_valid)
1974                                         transfer = (int)cmdstatp->uremainder64;
1975                                 else
1976                                         transfer = 0;
1977                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1978                                         if (STp->block_size == 0)
1979                                                 transfer = bytes;
1980                                         /* Some drives set ILI with MEDIUM ERROR */
1981                                         cmdstatp->flags &= ~SENSE_ILI;
1982                                 }
1983
1984                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1985                                         if (STp->block_size == 0 &&
1986                                             transfer < 0) {
1987                                                 st_printk(KERN_NOTICE, STp,
1988                                                           "Failed to read %d "
1989                                                           "byte block with %d "
1990                                                           "byte transfer.\n",
1991                                                           bytes - transfer,
1992                                                           bytes);
1993                                                 if (STps->drv_block >= 0)
1994                                                         STps->drv_block += 1;
1995                                                 STbp->buffer_bytes = 0;
1996                                                 return (-ENOMEM);
1997                                         } else if (STp->block_size == 0) {
1998                                                 STbp->buffer_bytes = bytes - transfer;
1999                                         } else {
2000                                                 st_release_request(SRpnt);
2001                                                 SRpnt = *aSRpnt = NULL;
2002                                                 if (transfer == blks) { /* We did not get anything, error */
2003                                                         st_printk(KERN_NOTICE, STp,
2004                                                                   "Incorrect "
2005                                                                   "block size.\n");
2006                                                         if (STps->drv_block >= 0)
2007                                                                 STps->drv_block += blks - transfer + 1;
2008                                                         st_int_ioctl(STp, MTBSR, 1);
2009                                                         return (-EIO);
2010                                                 }
2011                                                 /* We have some data, deliver it */
2012                                                 STbp->buffer_bytes = (blks - transfer) *
2013                                                     STp->block_size;
2014                                                 DEBC_printk(STp, "ILI but "
2015                                                             "enough data "
2016                                                             "received %ld "
2017                                                             "%d.\n", count,
2018                                                             STbp->buffer_bytes);
2019                                                 if (STps->drv_block >= 0)
2020                                                         STps->drv_block += 1;
2021                                                 if (st_int_ioctl(STp, MTBSR, 1))
2022                                                         return (-EIO);
2023                                         }
2024                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2025                                         if (STps->eof != ST_FM_HIT)
2026                                                 STps->eof = ST_FM_HIT;
2027                                         else
2028                                                 STps->eof = ST_EOD_2;
2029                                         if (STp->block_size == 0)
2030                                                 STbp->buffer_bytes = 0;
2031                                         else
2032                                                 STbp->buffer_bytes =
2033                                                     bytes - transfer * STp->block_size;
2034                                         DEBC_printk(STp, "EOF detected (%d "
2035                                                     "bytes read).\n",
2036                                                     STbp->buffer_bytes);
2037                                 } else if (cmdstatp->flags & SENSE_EOM) {
2038                                         if (STps->eof == ST_FM)
2039                                                 STps->eof = ST_EOD_1;
2040                                         else
2041                                                 STps->eof = ST_EOM_OK;
2042                                         if (STp->block_size == 0)
2043                                                 STbp->buffer_bytes = bytes - transfer;
2044                                         else
2045                                                 STbp->buffer_bytes =
2046                                                     bytes - transfer * STp->block_size;
2047
2048                                         DEBC_printk(STp, "EOM detected (%d "
2049                                                     "bytes read).\n",
2050                                                     STbp->buffer_bytes);
2051                                 }
2052                         }
2053                         /* end of EOF, EOM, ILI test */
2054                         else {  /* nonzero sense key */
2055                                 DEBC_printk(STp, "Tape error while reading.\n");
2056                                 STps->drv_block = (-1);
2057                                 if (STps->eof == ST_FM &&
2058                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2059                                         DEBC_printk(STp, "Zero returned for "
2060                                                     "first BLANK CHECK "
2061                                                     "after EOF.\n");
2062                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2063                                 } else  /* Some other extended sense code */
2064                                         retval = (-EIO);
2065                         }
2066
2067                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2068                                 STbp->buffer_bytes = 0;
2069                 }
2070                 /* End of extended sense test */
2071                 else {          /* Non-extended sense */
2072                         retval = STbp->syscall_result;
2073                 }
2074
2075         }
2076         /* End of error handling */
2077         else {                  /* Read successful */
2078                 STbp->buffer_bytes = bytes;
2079                 if (STp->sili) /* In fixed block mode residual is always zero here */
2080                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2081         }
2082
2083         if (STps->drv_block >= 0) {
2084                 if (STp->block_size == 0)
2085                         STps->drv_block++;
2086                 else
2087                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2088         }
2089         return retval;
2090 }
2091 \f
2092
2093 /* Read command */
2094 static ssize_t
2095 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2096 {
2097         ssize_t total;
2098         ssize_t retval = 0;
2099         ssize_t i, transfer;
2100         int special, do_dio = 0;
2101         struct st_request *SRpnt = NULL;
2102         struct scsi_tape *STp = filp->private_data;
2103         struct st_modedef *STm;
2104         struct st_partstat *STps;
2105         struct st_buffer *STbp = STp->buffer;
2106
2107         if (mutex_lock_interruptible(&STp->lock))
2108                 return -ERESTARTSYS;
2109
2110         retval = rw_checks(STp, filp, count);
2111         if (retval || count == 0)
2112                 goto out;
2113
2114         STm = &(STp->modes[STp->current_mode]);
2115         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2116                 if (!STm->do_read_ahead) {
2117                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2118                         goto out;
2119                 }
2120                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2121         }
2122
2123         STps = &(STp->ps[STp->partition]);
2124         if (STps->rw == ST_WRITING) {
2125                 retval = flush_buffer(STp, 0);
2126                 if (retval)
2127                         goto out;
2128                 STps->rw = ST_READING;
2129         }
2130         DEB(
2131         if (debugging && STps->eof != ST_NOEOF)
2132                 st_printk(ST_DEB_MSG, STp,
2133                           "EOF/EOM flag up (%d). Bytes %d\n",
2134                           STps->eof, STbp->buffer_bytes);
2135         ) /* end DEB */
2136
2137         retval = setup_buffering(STp, buf, count, 1);
2138         if (retval)
2139                 goto out;
2140         do_dio = STbp->do_dio;
2141
2142         if (STbp->buffer_bytes == 0 &&
2143             STps->eof >= ST_EOD_1) {
2144                 if (STps->eof < ST_EOD) {
2145                         STps->eof += 1;
2146                         retval = 0;
2147                         goto out;
2148                 }
2149                 retval = (-EIO);        /* EOM or Blank Check */
2150                 goto out;
2151         }
2152
2153         if (do_dio) {
2154                 /* Check the buffer writability before any tape movement. Don't alter
2155                    buffer data. */
2156                 if (copy_from_user(&i, buf, 1) != 0 ||
2157                     copy_to_user(buf, &i, 1) != 0 ||
2158                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2159                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2160                         retval = (-EFAULT);
2161                         goto out;
2162                 }
2163         }
2164
2165         STps->rw = ST_READING;
2166
2167
2168         /* Loop until enough data in buffer or a special condition found */
2169         for (total = 0, special = 0; total < count && !special;) {
2170
2171                 /* Get new data if the buffer is empty */
2172                 if (STbp->buffer_bytes == 0) {
2173                         special = read_tape(STp, count - total, &SRpnt);
2174                         if (special < 0) {      /* No need to continue read */
2175                                 retval = special;
2176                                 goto out;
2177                         }
2178                 }
2179
2180                 /* Move the data from driver buffer to user buffer */
2181                 if (STbp->buffer_bytes > 0) {
2182                         DEB(
2183                         if (debugging && STps->eof != ST_NOEOF)
2184                                 st_printk(ST_DEB_MSG, STp,
2185                                           "EOF up (%d). Left %d, needed %d.\n",
2186                                           STps->eof, STbp->buffer_bytes,
2187                                           (int)(count - total));
2188                         ) /* end DEB */
2189                         transfer = STbp->buffer_bytes < count - total ?
2190                             STbp->buffer_bytes : count - total;
2191                         if (!do_dio) {
2192                                 i = from_buffer(STbp, buf, transfer);
2193                                 if (i) {
2194                                         retval = i;
2195                                         goto out;
2196                                 }
2197                         }
2198                         buf += transfer;
2199                         total += transfer;
2200                 }
2201
2202                 if (STp->block_size == 0)
2203                         break;  /* Read only one variable length block */
2204
2205         }                       /* for (total = 0, special = 0;
2206                                    total < count && !special; ) */
2207
2208         /* Change the eof state if no data from tape or buffer */
2209         if (total == 0) {
2210                 if (STps->eof == ST_FM_HIT) {
2211                         STps->eof = ST_FM;
2212                         STps->drv_block = 0;
2213                         if (STps->drv_file >= 0)
2214                                 STps->drv_file++;
2215                 } else if (STps->eof == ST_EOD_1) {
2216                         STps->eof = ST_EOD_2;
2217                         STps->drv_block = 0;
2218                         if (STps->drv_file >= 0)
2219                                 STps->drv_file++;
2220                 } else if (STps->eof == ST_EOD_2)
2221                         STps->eof = ST_EOD;
2222         } else if (STps->eof == ST_FM)
2223                 STps->eof = ST_NOEOF;
2224         retval = total;
2225
2226  out:
2227         if (SRpnt != NULL) {
2228                 st_release_request(SRpnt);
2229                 SRpnt = NULL;
2230         }
2231         if (do_dio) {
2232                 release_buffering(STp, 1);
2233                 STbp->buffer_bytes = 0;
2234         }
2235         mutex_unlock(&STp->lock);
2236
2237         return retval;
2238 }
2239 \f
2240
2241
2242 DEB(
2243 /* Set the driver options */
2244 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2245 {
2246         if (debugging) {
2247                 st_printk(KERN_INFO, STp,
2248                           "Mode %d options: buffer writes: %d, "
2249                           "async writes: %d, read ahead: %d\n",
2250                           STp->current_mode, STm->do_buffer_writes,
2251                           STm->do_async_writes, STm->do_read_ahead);
2252                 st_printk(KERN_INFO, STp,
2253                           "    can bsr: %d, two FMs: %d, "
2254                           "fast mteom: %d, auto lock: %d,\n",
2255                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2256                           STp->do_auto_lock);
2257                 st_printk(KERN_INFO, STp,
2258                           "    defs for wr: %d, no block limits: %d, "
2259                           "partitions: %d, s2 log: %d\n",
2260                           STm->defaults_for_writes, STp->omit_blklims,
2261                           STp->can_partitions, STp->scsi2_logical);
2262                 st_printk(KERN_INFO, STp,
2263                           "    sysv: %d nowait: %d sili: %d "
2264                           "nowait_filemark: %d\n",
2265                           STm->sysv, STp->immediate, STp->sili,
2266                           STp->immediate_filemark);
2267                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2268         }
2269 }
2270         )
2271
2272
2273 static int st_set_options(struct scsi_tape *STp, long options)
2274 {
2275         int value;
2276         long code;
2277         struct st_modedef *STm;
2278         struct cdev *cd0, *cd1;
2279         struct device *d0, *d1;
2280
2281         STm = &(STp->modes[STp->current_mode]);
2282         if (!STm->defined) {
2283                 cd0 = STm->cdevs[0];
2284                 cd1 = STm->cdevs[1];
2285                 d0  = STm->devs[0];
2286                 d1  = STm->devs[1];
2287                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2288                 STm->cdevs[0] = cd0;
2289                 STm->cdevs[1] = cd1;
2290                 STm->devs[0]  = d0;
2291                 STm->devs[1]  = d1;
2292                 modes_defined = 1;
2293                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2294                             STp->current_mode);
2295         }
2296
2297         code = options & MT_ST_OPTIONS;
2298         if (code == MT_ST_BOOLEANS) {
2299                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2300                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2301                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2302                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2303                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2304                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2305                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2306                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2307                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2308                 if ((STp->device)->scsi_level >= SCSI_2)
2309                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2310                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2311                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2312                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2313                 STm->sysv = (options & MT_ST_SYSV) != 0;
2314                 STp->sili = (options & MT_ST_SILI) != 0;
2315                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2316                      st_log_options(STp, STm); )
2317         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2318                 value = (code == MT_ST_SETBOOLEANS);
2319                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2320                         STm->do_buffer_writes = value;
2321                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2322                         STm->do_async_writes = value;
2323                 if ((options & MT_ST_DEF_WRITES) != 0)
2324                         STm->defaults_for_writes = value;
2325                 if ((options & MT_ST_READ_AHEAD) != 0)
2326                         STm->do_read_ahead = value;
2327                 if ((options & MT_ST_TWO_FM) != 0)
2328                         STp->two_fm = value;
2329                 if ((options & MT_ST_FAST_MTEOM) != 0)
2330                         STp->fast_mteom = value;
2331                 if ((options & MT_ST_AUTO_LOCK) != 0)
2332                         STp->do_auto_lock = value;
2333                 if ((options & MT_ST_CAN_BSR) != 0)
2334                         STp->can_bsr = value;
2335                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2336                         STp->omit_blklims = value;
2337                 if ((STp->device)->scsi_level >= SCSI_2 &&
2338                     (options & MT_ST_CAN_PARTITIONS) != 0)
2339                         STp->can_partitions = value;
2340                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2341                         STp->scsi2_logical = value;
2342                 if ((options & MT_ST_NOWAIT) != 0)
2343                         STp->immediate = value;
2344                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2345                         STp->immediate_filemark = value;
2346                 if ((options & MT_ST_SYSV) != 0)
2347                         STm->sysv = value;
2348                 if ((options & MT_ST_SILI) != 0)
2349                         STp->sili = value;
2350                 DEB(
2351                 if ((options & MT_ST_DEBUGGING) != 0)
2352                         debugging = value;
2353                         st_log_options(STp, STm); )
2354         } else if (code == MT_ST_WRITE_THRESHOLD) {
2355                 /* Retained for compatibility */
2356         } else if (code == MT_ST_DEF_BLKSIZE) {
2357                 value = (options & ~MT_ST_OPTIONS);
2358                 if (value == ~MT_ST_OPTIONS) {
2359                         STm->default_blksize = (-1);
2360                         DEBC_printk(STp, "Default block size disabled.\n");
2361                 } else {
2362                         STm->default_blksize = value;
2363                         DEBC_printk(STp,"Default block size set to "
2364                                     "%d bytes.\n", STm->default_blksize);
2365                         if (STp->ready == ST_READY) {
2366                                 STp->blksize_changed = 0;
2367                                 set_mode_densblk(STp, STm);
2368                         }
2369                 }
2370         } else if (code == MT_ST_TIMEOUTS) {
2371                 value = (options & ~MT_ST_OPTIONS);
2372                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2373                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2374                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2375                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2376                 } else {
2377                         blk_queue_rq_timeout(STp->device->request_queue,
2378                                              value * HZ);
2379                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2380                                     value);
2381                 }
2382         } else if (code == MT_ST_SET_CLN) {
2383                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2384                 if (value != 0 &&
2385                         (value < EXTENDED_SENSE_START ||
2386                                 value >= SCSI_SENSE_BUFFERSIZE))
2387                         return (-EINVAL);
2388                 STp->cln_mode = value;
2389                 STp->cln_sense_mask = (options >> 8) & 0xff;
2390                 STp->cln_sense_value = (options >> 16) & 0xff;
2391                 st_printk(KERN_INFO, STp,
2392                           "Cleaning request mode %d, mask %02x, value %02x\n",
2393                           value, STp->cln_sense_mask, STp->cln_sense_value);
2394         } else if (code == MT_ST_DEF_OPTIONS) {
2395                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2396                 value = (options & MT_ST_CLEAR_DEFAULT);
2397                 if (code == MT_ST_DEF_DENSITY) {
2398                         if (value == MT_ST_CLEAR_DEFAULT) {
2399                                 STm->default_density = (-1);
2400                                 DEBC_printk(STp,
2401                                             "Density default disabled.\n");
2402                         } else {
2403                                 STm->default_density = value & 0xff;
2404                                 DEBC_printk(STp, "Density default set to %x\n",
2405                                             STm->default_density);
2406                                 if (STp->ready == ST_READY) {
2407                                         STp->density_changed = 0;
2408                                         set_mode_densblk(STp, STm);
2409                                 }
2410                         }
2411                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2412                         if (value == MT_ST_CLEAR_DEFAULT) {
2413                                 STp->default_drvbuffer = 0xff;
2414                                 DEBC_printk(STp,
2415                                             "Drive buffer default disabled.\n");
2416                         } else {
2417                                 STp->default_drvbuffer = value & 7;
2418                                 DEBC_printk(STp,
2419                                             "Drive buffer default set to %x\n",
2420                                             STp->default_drvbuffer);
2421                                 if (STp->ready == ST_READY)
2422                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2423                         }
2424                 } else if (code == MT_ST_DEF_COMPRESSION) {
2425                         if (value == MT_ST_CLEAR_DEFAULT) {
2426                                 STm->default_compression = ST_DONT_TOUCH;
2427                                 DEBC_printk(STp,
2428                                             "Compression default disabled.\n");
2429                         } else {
2430                                 if ((value & 0xff00) != 0) {
2431                                         STp->c_algo = (value & 0xff00) >> 8;
2432                                         DEBC_printk(STp, "Compression "
2433                                                     "algorithm set to 0x%x.\n",
2434                                                     STp->c_algo);
2435                                 }
2436                                 if ((value & 0xff) != 0xff) {
2437                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2438                                         DEBC_printk(STp, "Compression default "
2439                                                     "set to %x\n",
2440                                                     (value & 1));
2441                                         if (STp->ready == ST_READY) {
2442                                                 STp->compression_changed = 0;
2443                                                 st_compression(STp, (STm->default_compression == ST_YES));
2444                                         }
2445                                 }
2446                         }
2447                 }
2448         } else
2449                 return (-EIO);
2450
2451         return 0;
2452 }
2453 \f
2454 #define MODE_HEADER_LENGTH  4
2455
2456 /* Mode header and page byte offsets */
2457 #define MH_OFF_DATA_LENGTH     0
2458 #define MH_OFF_MEDIUM_TYPE     1
2459 #define MH_OFF_DEV_SPECIFIC    2
2460 #define MH_OFF_BDESCS_LENGTH   3
2461 #define MP_OFF_PAGE_NBR        0
2462 #define MP_OFF_PAGE_LENGTH     1
2463
2464 /* Mode header and page bit masks */
2465 #define MH_BIT_WP              0x80
2466 #define MP_MSK_PAGE_NBR        0x3f
2467
2468 /* Don't return block descriptors */
2469 #define MODE_SENSE_OMIT_BDESCS 0x08
2470
2471 #define MODE_SELECT_PAGE_FORMAT 0x10
2472
2473 /* Read a mode page into the tape buffer. The block descriptors are included
2474    if incl_block_descs is true. The page control is ored to the page number
2475    parameter, if necessary. */
2476 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2477 {
2478         unsigned char cmd[MAX_COMMAND_SIZE];
2479         struct st_request *SRpnt;
2480
2481         memset(cmd, 0, MAX_COMMAND_SIZE);
2482         cmd[0] = MODE_SENSE;
2483         if (omit_block_descs)
2484                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2485         cmd[2] = page;
2486         cmd[4] = 255;
2487
2488         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2489                            STp->device->request_queue->rq_timeout, 0, 1);
2490         if (SRpnt == NULL)
2491                 return (STp->buffer)->syscall_result;
2492
2493         st_release_request(SRpnt);
2494
2495         return STp->buffer->syscall_result;
2496 }
2497
2498
2499 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2500    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2501 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2502 {
2503         int pgo;
2504         unsigned char cmd[MAX_COMMAND_SIZE];
2505         struct st_request *SRpnt;
2506         int timeout;
2507
2508         memset(cmd, 0, MAX_COMMAND_SIZE);
2509         cmd[0] = MODE_SELECT;
2510         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2511         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2512         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2513
2514         /* Clear reserved fields */
2515         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2516         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2517         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2518         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2519
2520         timeout = slow ?
2521                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2522         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2523                            timeout, 0, 1);
2524         if (SRpnt == NULL)
2525                 return (STp->buffer)->syscall_result;
2526
2527         st_release_request(SRpnt);
2528
2529         return STp->buffer->syscall_result;
2530 }
2531
2532
2533 #define COMPRESSION_PAGE        0x0f
2534 #define COMPRESSION_PAGE_LENGTH 16
2535
2536 #define CP_OFF_DCE_DCC          2
2537 #define CP_OFF_C_ALGO           7
2538
2539 #define DCE_MASK  0x80
2540 #define DCC_MASK  0x40
2541 #define RED_MASK  0x60
2542
2543
2544 /* Control the compression with mode page 15. Algorithm not changed if zero.
2545
2546    The block descriptors are read and written because Sony SDT-7000 does not
2547    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2548    Including block descriptors should not cause any harm to other drives. */
2549
2550 static int st_compression(struct scsi_tape * STp, int state)
2551 {
2552         int retval;
2553         int mpoffs;  /* Offset to mode page start */
2554         unsigned char *b_data = (STp->buffer)->b_data;
2555
2556         if (STp->ready != ST_READY)
2557                 return (-EIO);
2558
2559         /* Read the current page contents */
2560         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2561         if (retval) {
2562                 DEBC_printk(STp, "Compression mode page not supported.\n");
2563                 return (-EIO);
2564         }
2565
2566         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2567         DEBC_printk(STp, "Compression state is %d.\n",
2568                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2569
2570         /* Check if compression can be changed */
2571         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2572                 DEBC_printk(STp, "Compression not supported.\n");
2573                 return (-EIO);
2574         }
2575
2576         /* Do the change */
2577         if (state) {
2578                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2579                 if (STp->c_algo != 0)
2580                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2581         }
2582         else {
2583                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2584                 if (STp->c_algo != 0)
2585                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2586         }
2587
2588         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2589         if (retval) {
2590                 DEBC_printk(STp, "Compression change failed.\n");
2591                 return (-EIO);
2592         }
2593         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2594
2595         STp->compression_changed = 1;
2596         return 0;
2597 }
2598
2599
2600 /* Process the load and unload commands (does unload if the load code is zero) */
2601 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2602 {
2603         int retval = (-EIO), timeout;
2604         unsigned char cmd[MAX_COMMAND_SIZE];
2605         struct st_partstat *STps;
2606         struct st_request *SRpnt;
2607
2608         if (STp->ready != ST_READY && !load_code) {
2609                 if (STp->ready == ST_NO_TAPE)
2610                         return (-ENOMEDIUM);
2611                 else
2612                         return (-EIO);
2613         }
2614
2615         memset(cmd, 0, MAX_COMMAND_SIZE);
2616         cmd[0] = START_STOP;
2617         if (load_code)
2618                 cmd[4] |= 1;
2619         /*
2620          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2621          */
2622         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2623             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2624                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2625                             (cmd[4]) ? "" : "un",
2626                             load_code - MT_ST_HPLOADER_OFFSET);
2627                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2628         }
2629         if (STp->immediate) {
2630                 cmd[1] = 1;     /* Don't wait for completion */
2631                 timeout = STp->device->request_queue->rq_timeout;
2632         }
2633         else
2634                 timeout = STp->long_timeout;
2635
2636         DEBC(
2637                 if (!load_code)
2638                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2639                 else
2640                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2641                 );
2642
2643         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2644                            timeout, MAX_RETRIES, 1);
2645         if (!SRpnt)
2646                 return (STp->buffer)->syscall_result;
2647
2648         retval = (STp->buffer)->syscall_result;
2649         st_release_request(SRpnt);
2650
2651         if (!retval) {  /* SCSI command successful */
2652
2653                 if (!load_code) {
2654                         STp->rew_at_close = 0;
2655                         STp->ready = ST_NO_TAPE;
2656                 }
2657                 else {
2658                         STp->rew_at_close = STp->autorew_dev;
2659                         retval = check_tape(STp, filp);
2660                         if (retval > 0)
2661                                 retval = 0;
2662                 }
2663         }
2664         else {
2665                 STps = &(STp->ps[STp->partition]);
2666                 STps->drv_file = STps->drv_block = (-1);
2667         }
2668
2669         return retval;
2670 }
2671 \f
2672 #if DEBUG
2673 #define ST_DEB_FORWARD  0
2674 #define ST_DEB_BACKWARD 1
2675 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2676 {
2677         s32 sc;
2678
2679         if (!debugging)
2680                 return;
2681
2682         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2683         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2684         if (direction)
2685                 sc = -sc;
2686         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2687                   direction ? "backward" : "forward", sc, units);
2688 }
2689 #else
2690 #define ST_DEB_FORWARD  0
2691 #define ST_DEB_BACKWARD 1
2692 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2693 #endif
2694
2695
2696 /* Internal ioctl function */
2697 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2698 {
2699         int timeout;
2700         long ltmp;
2701         int ioctl_result;
2702         int chg_eof = 1;
2703         unsigned char cmd[MAX_COMMAND_SIZE];
2704         struct st_request *SRpnt;
2705         struct st_partstat *STps;
2706         int fileno, blkno, at_sm, undone;
2707         int datalen = 0, direction = DMA_NONE;
2708
2709         WARN_ON(STp->buffer->do_dio != 0);
2710         if (STp->ready != ST_READY) {
2711                 if (STp->ready == ST_NO_TAPE)
2712                         return (-ENOMEDIUM);
2713                 else
2714                         return (-EIO);
2715         }
2716         timeout = STp->long_timeout;
2717         STps = &(STp->ps[STp->partition]);
2718         fileno = STps->drv_file;
2719         blkno = STps->drv_block;
2720         at_sm = STps->at_sm;
2721
2722         memset(cmd, 0, MAX_COMMAND_SIZE);
2723         switch (cmd_in) {
2724         case MTFSFM:
2725                 chg_eof = 0;    /* Changed from the FSF after this */
2726         case MTFSF:
2727                 cmd[0] = SPACE;
2728                 cmd[1] = 0x01;  /* Space FileMarks */
2729                 cmd[2] = (arg >> 16);
2730                 cmd[3] = (arg >> 8);
2731                 cmd[4] = arg;
2732                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2733                 if (fileno >= 0)
2734                         fileno += arg;
2735                 blkno = 0;
2736                 at_sm &= (arg == 0);
2737                 break;
2738         case MTBSFM:
2739                 chg_eof = 0;    /* Changed from the FSF after this */
2740         case MTBSF:
2741                 cmd[0] = SPACE;
2742                 cmd[1] = 0x01;  /* Space FileMarks */
2743                 ltmp = (-arg);
2744                 cmd[2] = (ltmp >> 16);
2745                 cmd[3] = (ltmp >> 8);
2746                 cmd[4] = ltmp;
2747                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2748                 if (fileno >= 0)
2749                         fileno -= arg;
2750                 blkno = (-1);   /* We can't know the block number */
2751                 at_sm &= (arg == 0);
2752                 break;
2753         case MTFSR:
2754                 cmd[0] = SPACE;
2755                 cmd[1] = 0x00;  /* Space Blocks */
2756                 cmd[2] = (arg >> 16);
2757                 cmd[3] = (arg >> 8);
2758                 cmd[4] = arg;
2759                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2760                 if (blkno >= 0)
2761                         blkno += arg;
2762                 at_sm &= (arg == 0);
2763                 break;
2764         case MTBSR:
2765                 cmd[0] = SPACE;
2766                 cmd[1] = 0x00;  /* Space Blocks */
2767                 ltmp = (-arg);
2768                 cmd[2] = (ltmp >> 16);
2769                 cmd[3] = (ltmp >> 8);
2770                 cmd[4] = ltmp;
2771                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2772                 if (blkno >= 0)
2773                         blkno -= arg;
2774                 at_sm &= (arg == 0);
2775                 break;
2776         case MTFSS:
2777                 cmd[0] = SPACE;
2778                 cmd[1] = 0x04;  /* Space Setmarks */
2779                 cmd[2] = (arg >> 16);
2780                 cmd[3] = (arg >> 8);
2781                 cmd[4] = arg;
2782                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2783                 if (arg != 0) {
2784                         blkno = fileno = (-1);
2785                         at_sm = 1;
2786                 }
2787                 break;
2788         case MTBSS:
2789                 cmd[0] = SPACE;
2790                 cmd[1] = 0x04;  /* Space Setmarks */
2791                 ltmp = (-arg);
2792                 cmd[2] = (ltmp >> 16);
2793                 cmd[3] = (ltmp >> 8);
2794                 cmd[4] = ltmp;
2795                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2796                 if (arg != 0) {
2797                         blkno = fileno = (-1);
2798                         at_sm = 1;
2799                 }
2800                 break;
2801         case MTWEOF:
2802         case MTWEOFI:
2803         case MTWSM:
2804                 if (STp->write_prot)
2805                         return (-EACCES);
2806                 cmd[0] = WRITE_FILEMARKS;
2807                 if (cmd_in == MTWSM)
2808                         cmd[1] = 2;
2809                 if (cmd_in == MTWEOFI ||
2810                     (cmd_in == MTWEOF && STp->immediate_filemark))
2811                         cmd[1] |= 1;
2812                 cmd[2] = (arg >> 16);
2813                 cmd[3] = (arg >> 8);
2814                 cmd[4] = arg;
2815                 timeout = STp->device->request_queue->rq_timeout;
2816                 DEBC(
2817                         if (cmd_in != MTWSM)
2818                                 st_printk(ST_DEB_MSG, STp,
2819                                           "Writing %d filemarks.\n",
2820                                           cmd[2] * 65536 +
2821                                           cmd[3] * 256 +
2822                                           cmd[4]);
2823                         else
2824                                 st_printk(ST_DEB_MSG, STp,
2825                                           "Writing %d setmarks.\n",
2826                                           cmd[2] * 65536 +
2827                                           cmd[3] * 256 +
2828                                           cmd[4]);
2829                 )
2830                 if (fileno >= 0)
2831                         fileno += arg;
2832                 blkno = 0;
2833                 at_sm = (cmd_in == MTWSM);
2834                 break;
2835         case MTREW:
2836                 cmd[0] = REZERO_UNIT;
2837                 if (STp->immediate) {
2838                         cmd[1] = 1;     /* Don't wait for completion */
2839                         timeout = STp->device->request_queue->rq_timeout;
2840                 }
2841                 DEBC_printk(STp, "Rewinding tape.\n");
2842                 fileno = blkno = at_sm = 0;
2843                 break;
2844         case MTNOP:
2845                 DEBC_printk(STp, "No op on tape.\n");
2846                 return 0;       /* Should do something ? */
2847                 break;
2848         case MTRETEN:
2849                 cmd[0] = START_STOP;
2850                 if (STp->immediate) {
2851                         cmd[1] = 1;     /* Don't wait for completion */
2852                         timeout = STp->device->request_queue->rq_timeout;
2853                 }
2854                 cmd[4] = 3;
2855                 DEBC_printk(STp, "Retensioning tape.\n");
2856                 fileno = blkno = at_sm = 0;
2857                 break;
2858         case MTEOM:
2859                 if (!STp->fast_mteom) {
2860                         /* space to the end of tape */
2861                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2862                         fileno = STps->drv_file;
2863                         if (STps->eof >= ST_EOD_1)
2864                                 return 0;
2865                         /* The next lines would hide the number of spaced FileMarks
2866                            That's why I inserted the previous lines. I had no luck
2867                            with detecting EOM with FSF, so we go now to EOM.
2868                            Joerg Weule */
2869                 } else
2870                         fileno = (-1);
2871                 cmd[0] = SPACE;
2872                 cmd[1] = 3;
2873                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2874                 blkno = -1;
2875                 at_sm = 0;
2876                 break;
2877         case MTERASE:
2878                 if (STp->write_prot)
2879                         return (-EACCES);
2880                 cmd[0] = ERASE;
2881                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2882                 if (STp->immediate) {
2883                         cmd[1] |= 2;    /* Don't wait for completion */
2884                         timeout = STp->device->request_queue->rq_timeout;
2885                 }
2886                 else
2887                         timeout = STp->long_timeout * 8;
2888
2889                 DEBC_printk(STp, "Erasing tape.\n");
2890                 fileno = blkno = at_sm = 0;
2891                 break;
2892         case MTSETBLK:          /* Set block length */
2893         case MTSETDENSITY:      /* Set tape density */
2894         case MTSETDRVBUFFER:    /* Set drive buffering */
2895         case SET_DENS_AND_BLK:  /* Set density and block size */
2896                 chg_eof = 0;
2897                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2898                         return (-EIO);  /* Not allowed if data in buffer */
2899                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2900                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2901                     STp->max_block > 0 &&
2902                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2903                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2904                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2905                         return (-EINVAL);
2906                 }
2907                 cmd[0] = MODE_SELECT;
2908                 if ((STp->use_pf & USE_PF))
2909                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2910                 cmd[4] = datalen = 12;
2911                 direction = DMA_TO_DEVICE;
2912
2913                 memset((STp->buffer)->b_data, 0, 12);
2914                 if (cmd_in == MTSETDRVBUFFER)
2915                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2916                 else
2917                         (STp->buffer)->b_data[2] =
2918                             STp->drv_buffer << 4;
2919                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2920                 if (cmd_in == MTSETDENSITY) {
2921                         (STp->buffer)->b_data[4] = arg;
2922                         STp->density_changed = 1;       /* At least we tried ;-) */
2923                 } else if (cmd_in == SET_DENS_AND_BLK)
2924                         (STp->buffer)->b_data[4] = arg >> 24;
2925                 else
2926                         (STp->buffer)->b_data[4] = STp->density;
2927                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2928                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2929                         if (cmd_in == MTSETBLK)
2930                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2931                 } else
2932                         ltmp = STp->block_size;
2933                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2934                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2935                 (STp->buffer)->b_data[11] = ltmp;
2936                 timeout = STp->device->request_queue->rq_timeout;
2937                 DEBC(
2938                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2939                                 st_printk(ST_DEB_MSG, STp,
2940                                           "Setting block size to %d bytes.\n",
2941                                           (STp->buffer)->b_data[9] * 65536 +
2942                                           (STp->buffer)->b_data[10] * 256 +
2943                                           (STp->buffer)->b_data[11]);
2944                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2945                                 st_printk(ST_DEB_MSG, STp,
2946                                           "Setting density code to %x.\n",
2947                                           (STp->buffer)->b_data[4]);
2948                         if (cmd_in == MTSETDRVBUFFER)
2949                                 st_printk(ST_DEB_MSG, STp,
2950                                           "Setting drive buffer code to %d.\n",
2951                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2952                 )
2953                 break;
2954         default:
2955                 return (-ENOSYS);
2956         }
2957
2958         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2959                            timeout, MAX_RETRIES, 1);
2960         if (!SRpnt)
2961                 return (STp->buffer)->syscall_result;
2962
2963         ioctl_result = (STp->buffer)->syscall_result;
2964
2965         if (!ioctl_result) {    /* SCSI command successful */
2966                 st_release_request(SRpnt);
2967                 SRpnt = NULL;
2968                 STps->drv_block = blkno;
2969                 STps->drv_file = fileno;
2970                 STps->at_sm = at_sm;
2971
2972                 if (cmd_in == MTBSFM)
2973                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2974                 else if (cmd_in == MTFSFM)
2975                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2976
2977                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2978                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2979                         if (STp->block_size != 0) {
2980                                 (STp->buffer)->buffer_blocks =
2981                                     (STp->buffer)->buffer_size / STp->block_size;
2982                         }
2983                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2984                         if (cmd_in == SET_DENS_AND_BLK)
2985                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2986                 } else if (cmd_in == MTSETDRVBUFFER)
2987                         STp->drv_buffer = (arg & 7);
2988                 else if (cmd_in == MTSETDENSITY)
2989                         STp->density = arg;
2990
2991                 if (cmd_in == MTEOM)
2992                         STps->eof = ST_EOD;
2993                 else if (cmd_in == MTFSF)
2994                         STps->eof = ST_FM;
2995                 else if (chg_eof)
2996                         STps->eof = ST_NOEOF;
2997
2998                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2999                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3000         } else { /* SCSI command was not completely successful. Don't return
3001                     from this block without releasing the SCSI command block! */
3002                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3003
3004                 if (cmdstatp->flags & SENSE_EOM) {
3005                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3006                             cmd_in != MTBSR && cmd_in != MTBSS)
3007                                 STps->eof = ST_EOM_OK;
3008                         STps->drv_block = 0;
3009                 }
3010
3011                 if (cmdstatp->remainder_valid)
3012                         undone = (int)cmdstatp->uremainder64;
3013                 else
3014                         undone = 0;
3015
3016                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3017                     cmdstatp->have_sense &&
3018                     (cmdstatp->flags & SENSE_EOM)) {
3019                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3020                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3021                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3022                                 STps->eof = ST_NOEOF;
3023                         } else {  /* Writing EOF(s) failed */
3024                                 if (fileno >= 0)
3025                                         fileno -= undone;
3026                                 if (undone < arg)
3027                                         STps->eof = ST_NOEOF;
3028                         }
3029                         STps->drv_file = fileno;
3030                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3031                         if (fileno >= 0)
3032                                 STps->drv_file = fileno - undone;
3033                         else
3034                                 STps->drv_file = fileno;
3035                         STps->drv_block = -1;
3036                         STps->eof = ST_NOEOF;
3037                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3038                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3039                                 undone = (-undone);
3040                         if (STps->drv_file >= 0)
3041                                 STps->drv_file = fileno + undone;
3042                         STps->drv_block = 0;
3043                         STps->eof = ST_NOEOF;
3044                 } else if (cmd_in == MTFSR) {
3045                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3046                                 if (STps->drv_file >= 0)
3047                                         STps->drv_file++;
3048                                 STps->drv_block = 0;
3049                                 STps->eof = ST_FM;
3050                         } else {
3051                                 if (blkno >= undone)
3052                                         STps->drv_block = blkno - undone;
3053                                 else
3054                                         STps->drv_block = (-1);
3055                                 STps->eof = ST_NOEOF;
3056                         }
3057                 } else if (cmd_in == MTBSR) {
3058                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3059                                 STps->drv_file--;
3060                                 STps->drv_block = (-1);
3061                         } else {
3062                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3063                                         undone = (-undone);
3064                                 if (STps->drv_block >= 0)
3065                                         STps->drv_block = blkno + undone;
3066                         }
3067                         STps->eof = ST_NOEOF;
3068                 } else if (cmd_in == MTEOM) {
3069                         STps->drv_file = (-1);
3070                         STps->drv_block = (-1);
3071                         STps->eof = ST_EOD;
3072                 } else if (cmd_in == MTSETBLK ||
3073                            cmd_in == MTSETDENSITY ||
3074                            cmd_in == MTSETDRVBUFFER ||
3075                            cmd_in == SET_DENS_AND_BLK) {
3076                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3077                             !(STp->use_pf & PF_TESTED)) {
3078                                 /* Try the other possible state of Page Format if not
3079                                    already tried */
3080                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3081                                 st_release_request(SRpnt);
3082                                 SRpnt = NULL;
3083                                 return st_int_ioctl(STp, cmd_in, arg);
3084                         }
3085                 } else if (chg_eof)
3086                         STps->eof = ST_NOEOF;
3087
3088                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3089                         STps->eof = ST_EOD;
3090
3091                 st_release_request(SRpnt);
3092                 SRpnt = NULL;
3093         }
3094
3095         return ioctl_result;
3096 }
3097 \f
3098
3099 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3100    structure. */
3101
3102 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3103                         int logical)
3104 {
3105         int result;
3106         unsigned char scmd[MAX_COMMAND_SIZE];
3107         struct st_request *SRpnt;
3108
3109         if (STp->ready != ST_READY)
3110                 return (-EIO);
3111
3112         memset(scmd, 0, MAX_COMMAND_SIZE);
3113         if ((STp->device)->scsi_level < SCSI_2) {
3114                 scmd[0] = QFA_REQUEST_BLOCK;
3115                 scmd[4] = 3;
3116         } else {
3117                 scmd[0] = READ_POSITION;
3118                 if (!logical && !STp->scsi2_logical)
3119                         scmd[1] = 1;
3120         }
3121         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3122                            STp->device->request_queue->rq_timeout,
3123                            MAX_READY_RETRIES, 1);
3124         if (!SRpnt)
3125                 return (STp->buffer)->syscall_result;
3126
3127         if ((STp->buffer)->syscall_result != 0 ||
3128             (STp->device->scsi_level >= SCSI_2 &&
3129              ((STp->buffer)->b_data[0] & 4) != 0)) {
3130                 *block = *partition = 0;
3131                 DEBC_printk(STp, " Can't read tape position.\n");
3132                 result = (-EIO);
3133         } else {
3134                 result = 0;
3135                 if ((STp->device)->scsi_level < SCSI_2) {
3136                         *block = ((STp->buffer)->b_data[0] << 16)
3137                             + ((STp->buffer)->b_data[1] << 8)
3138                             + (STp->buffer)->b_data[2];
3139                         *partition = 0;
3140                 } else {
3141                         *block = ((STp->buffer)->b_data[4] << 24)
3142                             + ((STp->buffer)->b_data[5] << 16)
3143                             + ((STp->buffer)->b_data[6] << 8)
3144                             + (STp->buffer)->b_data[7];
3145                         *partition = (STp->buffer)->b_data[1];
3146                         if (((STp->buffer)->b_data[0] & 0x80) &&
3147                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3148                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3149                 }
3150                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3151                             *block, *partition);
3152         }
3153         st_release_request(SRpnt);
3154         SRpnt = NULL;
3155
3156         return result;
3157 }
3158
3159
3160 /* Set the tape block and partition. Negative partition means that only the
3161    block should be set in vendor specific way. */
3162 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3163                         int logical)
3164 {
3165         struct st_partstat *STps;
3166         int result, p;
3167         unsigned int blk;
3168         int timeout;
3169         unsigned char scmd[MAX_COMMAND_SIZE];
3170         struct st_request *SRpnt;
3171
3172         if (STp->ready != ST_READY)
3173                 return (-EIO);
3174         timeout = STp->long_timeout;
3175         STps = &(STp->ps[STp->partition]);
3176
3177         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3178                     block, partition);
3179         DEB(if (partition < 0)
3180                 return (-EIO); )
3181
3182         /* Update the location at the partition we are leaving */
3183         if ((!STp->can_partitions && partition != 0) ||
3184             partition >= ST_NBR_PARTITIONS)
3185                 return (-EINVAL);
3186         if (partition != STp->partition) {
3187                 if (get_location(STp, &blk, &p, 1))
3188                         STps->last_block_valid = 0;
3189                 else {
3190                         STps->last_block_valid = 1;
3191                         STps->last_block_visited = blk;
3192                         DEBC_printk(STp, "Visited block %d for "
3193                                     "partition %d saved.\n",
3194                                     blk, STp->partition);
3195                 }
3196         }
3197
3198         memset(scmd, 0, MAX_COMMAND_SIZE);
3199         if ((STp->device)->scsi_level < SCSI_2) {
3200                 scmd[0] = QFA_SEEK_BLOCK;
3201                 scmd[2] = (block >> 16);
3202                 scmd[3] = (block >> 8);
3203                 scmd[4] = block;
3204                 scmd[5] = 0;
3205         } else {
3206                 scmd[0] = SEEK_10;
3207                 scmd[3] = (block >> 24);
3208                 scmd[4] = (block >> 16);
3209                 scmd[5] = (block >> 8);
3210                 scmd[6] = block;
3211                 if (!logical && !STp->scsi2_logical)
3212                         scmd[1] = 4;
3213                 if (STp->partition != partition) {
3214                         scmd[1] |= 2;
3215                         scmd[8] = partition;
3216                         DEBC_printk(STp, "Trying to change partition "
3217                                     "from %d to %d\n", STp->partition,
3218                                     partition);
3219                 }
3220         }
3221         if (STp->immediate) {
3222                 scmd[1] |= 1;           /* Don't wait for completion */
3223                 timeout = STp->device->request_queue->rq_timeout;
3224         }
3225
3226         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3227                            timeout, MAX_READY_RETRIES, 1);
3228         if (!SRpnt)
3229                 return (STp->buffer)->syscall_result;
3230
3231         STps->drv_block = STps->drv_file = (-1);
3232         STps->eof = ST_NOEOF;
3233         if ((STp->buffer)->syscall_result != 0) {
3234                 result = (-EIO);
3235                 if (STp->can_partitions &&
3236                     (STp->device)->scsi_level >= SCSI_2 &&
3237                     (p = find_partition(STp)) >= 0)
3238                         STp->partition = p;
3239         } else {
3240                 if (STp->can_partitions) {
3241                         STp->partition = partition;
3242                         STps = &(STp->ps[partition]);
3243                         if (!STps->last_block_valid ||
3244                             STps->last_block_visited != block) {
3245                                 STps->at_sm = 0;
3246                                 STps->rw = ST_IDLE;
3247                         }
3248                 } else
3249                         STps->at_sm = 0;
3250                 if (block == 0)
3251                         STps->drv_block = STps->drv_file = 0;
3252                 result = 0;
3253         }
3254
3255         st_release_request(SRpnt);
3256         SRpnt = NULL;
3257
3258         return result;
3259 }
3260
3261
3262 /* Find the current partition number for the drive status. Called from open and
3263    returns either partition number of negative error code. */
3264 static int find_partition(struct scsi_tape *STp)
3265 {
3266         int i, partition;
3267         unsigned int block;
3268
3269         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3270                 return i;
3271         if (partition >= ST_NBR_PARTITIONS)
3272                 return (-EIO);
3273         return partition;
3274 }
3275
3276
3277 /* Change the partition if necessary */
3278 static int switch_partition(struct scsi_tape *STp)
3279 {
3280         struct st_partstat *STps;
3281
3282         if (STp->partition == STp->new_partition)
3283                 return 0;
3284         STps = &(STp->ps[STp->new_partition]);
3285         if (!STps->last_block_valid)
3286                 STps->last_block_visited = 0;
3287         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3288 }
3289 \f
3290 /* Functions for reading and writing the medium partition mode page. */
3291
3292 #define PART_PAGE   0x11
3293 #define PART_PAGE_FIXED_LENGTH 8
3294
3295 #define PP_OFF_MAX_ADD_PARTS   2
3296 #define PP_OFF_NBR_ADD_PARTS   3
3297 #define PP_OFF_FLAGS           4
3298 #define PP_OFF_PART_UNITS      6
3299 #define PP_OFF_RESERVED        7
3300
3301 #define PP_BIT_IDP             0x20
3302 #define PP_BIT_FDP             0x80
3303 #define PP_MSK_PSUM_MB         0x10
3304 #define PP_MSK_PSUM_UNITS      0x18
3305 #define PP_MSK_POFM            0x04
3306
3307 /* Get the number of partitions on the tape. As a side effect reads the
3308    mode page into the tape buffer. */
3309 static int nbr_partitions(struct scsi_tape *STp)
3310 {
3311         int result;
3312
3313         if (STp->ready != ST_READY)
3314                 return (-EIO);
3315
3316         result = read_mode_page(STp, PART_PAGE, 1);
3317
3318         if (result) {
3319                 DEBC_printk(STp, "Can't read medium partition page.\n");
3320                 result = (-EIO);
3321         } else {
3322                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3323                                               PP_OFF_NBR_ADD_PARTS] + 1;
3324                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3325         }
3326
3327         return result;
3328 }
3329
3330
3331 static int format_medium(struct scsi_tape *STp, int format)
3332 {
3333         int result = 0;
3334         int timeout = STp->long_timeout;
3335         unsigned char scmd[MAX_COMMAND_SIZE];
3336         struct st_request *SRpnt;
3337
3338         memset(scmd, 0, MAX_COMMAND_SIZE);
3339         scmd[0] = FORMAT_UNIT;
3340         scmd[2] = format;
3341         if (STp->immediate) {
3342                 scmd[1] |= 1;           /* Don't wait for completion */
3343                 timeout = STp->device->request_queue->rq_timeout;
3344         }
3345         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3346         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3347                            timeout, MAX_RETRIES, 1);
3348         if (!SRpnt)
3349                 result = STp->buffer->syscall_result;
3350         return result;
3351 }
3352
3353
3354 /* Partition the tape into two partitions if size > 0 or one partition if
3355    size == 0.
3356
3357    The block descriptors are read and written because Sony SDT-7000 does not
3358    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3359
3360    My HP C1533A drive returns only one partition size field. This is used to
3361    set the size of partition 1. There is no size field for the default partition.
3362    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3363    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3364    The following algorithm is used to accommodate both drives: if the number of
3365    partition size fields is greater than the maximum number of additional partitions
3366    in the mode page, the second field is used. Otherwise the first field is used.
3367
3368    For Seagate DDS drives the page length must be 8 when no partitions is defined
3369    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3370    is acceptable also to some other old drives and enforced if the first partition
3371    size field is used for the first additional partition size.
3372
3373    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3374  */
3375 static int partition_tape(struct scsi_tape *STp, int size)
3376 {
3377         int result;
3378         int target_partition;
3379         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3380         int pgo, psd_cnt, psdo;
3381         int psum = PP_MSK_PSUM_MB, units = 0;
3382         unsigned char *bp;
3383
3384         result = read_mode_page(STp, PART_PAGE, 0);
3385         if (result) {
3386                 DEBC_printk(STp, "Can't read partition mode page.\n");
3387                 return result;
3388         }
3389         target_partition = 1;
3390         if (size < 0) {
3391                 target_partition = 0;
3392                 size = -size;
3393         }
3394
3395         /* The mode page is in the buffer. Let's modify it and write it. */
3396         bp = (STp->buffer)->b_data;
3397         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3398         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3399                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3400
3401         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3402
3403         if (scsi3) {
3404                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3405                 if (needs_format && size == 0) {
3406                         /* No need to write the mode page when clearing
3407                          *  partitioning
3408                          */
3409                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3410                         result = format_medium(STp, 0);
3411                         goto out;
3412                 }
3413                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3414                         psd_cnt = 2;
3415                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3416                         /* Use units scaling for large partitions if the device
3417                          * suggests it and no precision lost. Required for IBM
3418                          * TS1140/50 drives that don't support MB units.
3419                          */
3420                         if (size >= 1000 && (size % 1000) == 0) {
3421                                 size /= 1000;
3422                                 psum = PP_MSK_PSUM_UNITS;
3423                                 units = 9; /* GB */
3424                         }
3425                 }
3426                 /* Try it anyway if too large to specify in MB */
3427                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3428                         size /= 1000;
3429                         psum = PP_MSK_PSUM_UNITS;
3430                         units = 9;  /* GB */
3431                 }
3432         }
3433
3434         if (size >= 65535 ||  /* Does not fit into two bytes */
3435             (target_partition == 0 && psd_cnt < 2)) {
3436                 result = -EINVAL;
3437                 goto out;
3438         }
3439
3440         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3441         /* The second condition is for HP DDS which use only one partition size
3442          * descriptor
3443          */
3444         if (target_partition > 0 &&
3445             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3446              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3447                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3448                 psdo += 2;
3449         }
3450         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3451
3452         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3453                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3454                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3455
3456         if (size == 0) {
3457                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3458                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3459                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3460                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3461         } else {
3462                 bp[psdo] = (size >> 8) & 0xff;
3463                 bp[psdo + 1] = size & 0xff;
3464                 if (target_partition == 0)
3465                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3466                 bp[pgo + 3] = 1;
3467                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3468                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3469                 DEBC_printk(STp,
3470                             "Formatting tape with two partitions (%i = %d MB).\n",
3471                             target_partition, units > 0 ? size * 1000 : size);
3472         }
3473         bp[pgo + PP_OFF_PART_UNITS] = 0;
3474         bp[pgo + PP_OFF_RESERVED] = 0;
3475         if (size != 1 || units != 0) {
3476                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3477                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3478                 bp[pgo + PP_OFF_PART_UNITS] = units;
3479         } else
3480                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3481                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3482         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3483
3484         result = write_mode_page(STp, PART_PAGE, 1);
3485
3486         if (!result && needs_format)
3487                 result = format_medium(STp, 1);
3488
3489         if (result) {
3490                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3491                 result = (-EIO);
3492         }
3493
3494 out:
3495         return result;
3496 }
3497 \f
3498
3499
3500 /* The ioctl command */
3501 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3502 {
3503         int i, cmd_nr, cmd_type, bt;
3504         int retval = 0;
3505         unsigned int blk;
3506         struct scsi_tape *STp = file->private_data;
3507         struct st_modedef *STm;
3508         struct st_partstat *STps;
3509         void __user *p = (void __user *)arg;
3510
3511         if (mutex_lock_interruptible(&STp->lock))
3512                 return -ERESTARTSYS;
3513
3514         DEB(
3515         if (debugging && !STp->in_use) {
3516                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3517                 retval = (-EIO);
3518                 goto out;
3519         } ) /* end DEB */
3520
3521         STm = &(STp->modes[STp->current_mode]);
3522         STps = &(STp->ps[STp->partition]);
3523
3524         /*
3525          * If we are in the middle of error recovery, don't let anyone
3526          * else try and use this device.  Also, if error recovery fails, it
3527          * may try and take the device offline, in which case all further
3528          * access to the device is prohibited.
3529          */
3530         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3531                         file->f_flags & O_NDELAY);
3532         if (retval)
3533                 goto out;
3534
3535         cmd_type = _IOC_TYPE(cmd_in);
3536         cmd_nr = _IOC_NR(cmd_in);
3537
3538         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3539                 struct mtop mtc;
3540
3541                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3542                         retval = (-EINVAL);
3543                         goto out;
3544                 }
3545
3546                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3547                 if (i) {
3548                         retval = (-EFAULT);
3549                         goto out;
3550                 }
3551
3552                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3553                         st_printk(KERN_WARNING, STp,
3554                                   "MTSETDRVBUFFER only allowed for root.\n");
3555                         retval = (-EPERM);
3556                         goto out;
3557                 }
3558                 if (!STm->defined &&
3559                     (mtc.mt_op != MTSETDRVBUFFER &&
3560                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3561                         retval = (-ENXIO);
3562                         goto out;
3563                 }
3564
3565                 if (!STp->pos_unknown) {
3566
3567                         if (STps->eof == ST_FM_HIT) {
3568                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3569                                     mtc.mt_op == MTEOM) {
3570                                         mtc.mt_count -= 1;
3571                                         if (STps->drv_file >= 0)
3572                                                 STps->drv_file += 1;
3573                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3574                                         mtc.mt_count += 1;
3575                                         if (STps->drv_file >= 0)
3576                                                 STps->drv_file += 1;
3577                                 }
3578                         }
3579
3580                         if (mtc.mt_op == MTSEEK) {
3581                                 /* Old position must be restored if partition will be
3582                                    changed */
3583                                 i = !STp->can_partitions ||
3584                                     (STp->new_partition != STp->partition);
3585                         } else {
3586                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3587                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3588                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3589                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3590                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3591                                     mtc.mt_op == MTCOMPRESSION;
3592                         }
3593                         i = flush_buffer(STp, i);
3594                         if (i < 0) {
3595                                 retval = i;
3596                                 goto out;
3597                         }
3598                         if (STps->rw == ST_WRITING &&
3599                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3600                              mtc.mt_op == MTSEEK ||
3601                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3602                                 i = st_int_ioctl(STp, MTWEOF, 1);
3603                                 if (i < 0) {
3604                                         retval = i;
3605                                         goto out;
3606                                 }
3607                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3608                                         mtc.mt_count++;
3609                                 STps->rw = ST_IDLE;
3610                              }
3611
3612                 } else {
3613                         /*
3614                          * If there was a bus reset, block further access
3615                          * to this device.  If the user wants to rewind the tape,
3616                          * then reset the flag and allow access again.
3617                          */
3618                         if (mtc.mt_op != MTREW &&
3619                             mtc.mt_op != MTOFFL &&
3620                             mtc.mt_op != MTRETEN &&
3621                             mtc.mt_op != MTERASE &&
3622                             mtc.mt_op != MTSEEK &&
3623                             mtc.mt_op != MTEOM) {
3624                                 retval = (-EIO);
3625                                 goto out;
3626                         }
3627                         reset_state(STp);
3628                         /* remove this when the midlevel properly clears was_reset */
3629                         STp->device->was_reset = 0;
3630                 }
3631
3632                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3633                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3634                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3635                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3636
3637                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3638                         do_door_lock(STp, 0);   /* Ignore result! */
3639
3640                 if (mtc.mt_op == MTSETDRVBUFFER &&
3641                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3642                         retval = st_set_options(STp, mtc.mt_count);
3643                         goto out;
3644                 }
3645
3646                 if (mtc.mt_op == MTSETPART) {
3647                         if (!STp->can_partitions ||
3648                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3649                                 retval = (-EINVAL);
3650                                 goto out;
3651                         }
3652                         if (mtc.mt_count >= STp->nbr_partitions &&
3653                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3654                                 retval = (-EIO);
3655                                 goto out;
3656                         }
3657                         if (mtc.mt_count >= STp->nbr_partitions) {
3658                                 retval = (-EINVAL);
3659                                 goto out;
3660                         }
3661                         STp->new_partition = mtc.mt_count;
3662                         retval = 0;
3663                         goto out;
3664                 }
3665
3666                 if (mtc.mt_op == MTMKPART) {
3667                         if (!STp->can_partitions) {
3668                                 retval = (-EINVAL);
3669                                 goto out;
3670                         }
3671                         i = do_load_unload(STp, file, 1);
3672                         if (i < 0) {
3673                                 retval = i;
3674                                 goto out;
3675                         }
3676                         i = partition_tape(STp, mtc.mt_count);
3677                         if (i < 0) {
3678                                 retval = i;
3679                                 goto out;
3680                         }
3681                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3682                                 STp->ps[i].rw = ST_IDLE;
3683                                 STp->ps[i].at_sm = 0;
3684                                 STp->ps[i].last_block_valid = 0;
3685                         }
3686                         STp->partition = STp->new_partition = 0;
3687                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3688                         STps->drv_block = STps->drv_file = 0;
3689                         retval = 0;
3690                         goto out;
3691                 }
3692
3693                 if (mtc.mt_op == MTSEEK) {
3694                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3695                         if (!STp->can_partitions)
3696                                 STp->ps[0].rw = ST_IDLE;
3697                         retval = i;
3698                         goto out;
3699                 }
3700
3701                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3702                         retval = do_load_unload(STp, file, 0);
3703                         goto out;
3704                 }
3705
3706                 if (mtc.mt_op == MTLOAD) {
3707                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3708                         goto out;
3709                 }
3710
3711                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3712                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3713                         goto out;
3714                 }
3715
3716                 if (STp->can_partitions && STp->ready == ST_READY &&
3717                     (i = switch_partition(STp)) < 0) {
3718                         retval = i;
3719                         goto out;
3720                 }
3721
3722                 if (mtc.mt_op == MTCOMPRESSION)
3723                         retval = st_compression(STp, (mtc.mt_count & 1));
3724                 else
3725                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3726                 goto out;
3727         }
3728         if (!STm->defined) {
3729                 retval = (-ENXIO);
3730                 goto out;
3731         }
3732
3733         if ((i = flush_buffer(STp, 0)) < 0) {
3734                 retval = i;
3735                 goto out;
3736         }
3737         if (STp->can_partitions &&
3738             (i = switch_partition(STp)) < 0) {
3739                 retval = i;
3740                 goto out;
3741         }
3742
3743         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3744                 struct mtget mt_status;
3745
3746                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3747                          retval = (-EINVAL);
3748                          goto out;
3749                 }
3750
3751                 mt_status.mt_type = STp->tape_type;
3752                 mt_status.mt_dsreg =
3753                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3754                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3755                 mt_status.mt_blkno = STps->drv_block;
3756                 mt_status.mt_fileno = STps->drv_file;
3757                 if (STp->block_size != 0) {
3758                         if (STps->rw == ST_WRITING)
3759                                 mt_status.mt_blkno +=
3760                                     (STp->buffer)->buffer_bytes / STp->block_size;
3761                         else if (STps->rw == ST_READING)
3762                                 mt_status.mt_blkno -=
3763                                         ((STp->buffer)->buffer_bytes +
3764                                          STp->block_size - 1) / STp->block_size;
3765                 }
3766
3767                 mt_status.mt_gstat = 0;
3768                 if (STp->drv_write_prot)
3769                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3770                 if (mt_status.mt_blkno == 0) {
3771                         if (mt_status.mt_fileno == 0)
3772                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3773                         else
3774                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3775                 }
3776                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3777                 mt_status.mt_resid = STp->partition;
3778                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3779                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3780                 else if (STps->eof >= ST_EOM_OK)
3781                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3782                 if (STp->density == 1)
3783                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3784                 else if (STp->density == 2)
3785                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3786                 else if (STp->density == 3)
3787                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3788                 if (STp->ready == ST_READY)
3789                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3790                 if (STp->ready == ST_NO_TAPE)
3791                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3792                 if (STps->at_sm)
3793                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3794                 if (STm->do_async_writes ||
3795                     (STm->do_buffer_writes && STp->block_size != 0) ||
3796                     STp->drv_buffer != 0)
3797                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3798                 if (STp->cleaning_req)
3799                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3800
3801                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3802                 if (i) {
3803                         retval = (-EFAULT);
3804                         goto out;
3805                 }
3806
3807                 STp->recover_reg = 0;           /* Clear after read */
3808                 retval = 0;
3809                 goto out;
3810         }                       /* End of MTIOCGET */
3811         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3812                 struct mtpos mt_pos;
3813                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3814                          retval = (-EINVAL);
3815                          goto out;
3816                 }
3817                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3818                         retval = i;
3819                         goto out;
3820                 }
3821                 mt_pos.mt_blkno = blk;
3822                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3823                 if (i)
3824                         retval = (-EFAULT);
3825                 goto out;
3826         }
3827         mutex_unlock(&STp->lock);
3828         switch (cmd_in) {
3829                 case SCSI_IOCTL_GET_IDLUN:
3830                 case SCSI_IOCTL_GET_BUS_NUMBER:
3831                         break;
3832                 default:
3833                         if ((cmd_in == SG_IO ||
3834                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3835                              cmd_in == CDROM_SEND_PACKET) &&
3836                             !capable(CAP_SYS_RAWIO))
3837                                 i = -EPERM;
3838                         else
3839                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3840                                                    file->f_mode, cmd_in, p);
3841                         if (i != -ENOTTY)
3842                                 return i;
3843                         break;
3844         }
3845         retval = scsi_ioctl(STp->device, cmd_in, p);
3846         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3847                 STp->rew_at_close = 0;
3848                 STp->ready = ST_NO_TAPE;
3849         }
3850         return retval;
3851
3852  out:
3853         mutex_unlock(&STp->lock);
3854         return retval;
3855 }
3856
3857 #ifdef CONFIG_COMPAT
3858 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3859 {
3860         struct scsi_tape *STp = file->private_data;
3861         struct scsi_device *sdev = STp->device;
3862         int ret = -ENOIOCTLCMD;
3863         if (sdev->host->hostt->compat_ioctl) {
3864
3865                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3866
3867         }
3868         return ret;
3869 }
3870 #endif
3871
3872 \f
3873
3874 /* Try to allocate a new tape buffer. Calling function must not hold
3875    dev_arr_lock. */
3876 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3877 {
3878         struct st_buffer *tb;
3879
3880         tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3881         if (!tb) {
3882                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3883                 return NULL;
3884         }
3885         tb->frp_segs = 0;
3886         tb->use_sg = max_sg;
3887         tb->dma = need_dma;
3888         tb->buffer_size = 0;
3889
3890         tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3891                                      GFP_ATOMIC);
3892         if (!tb->reserved_pages) {
3893                 kfree(tb);
3894                 return NULL;
3895         }
3896
3897         return tb;
3898 }
3899
3900
3901 /* Try to allocate enough space in the tape buffer */
3902 #define ST_MAX_ORDER 6
3903
3904 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3905 {
3906         int segs, max_segs, b_size, order, got;
3907         gfp_t priority;
3908
3909         if (new_size <= STbuffer->buffer_size)
3910                 return 1;
3911
3912         if (STbuffer->buffer_size <= PAGE_SIZE)
3913                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3914
3915         max_segs = STbuffer->use_sg;
3916
3917         priority = GFP_KERNEL | __GFP_NOWARN;
3918         if (need_dma)
3919                 priority |= GFP_DMA;
3920
3921         if (STbuffer->cleared)
3922                 priority |= __GFP_ZERO;
3923
3924         if (STbuffer->frp_segs) {
3925                 order = STbuffer->reserved_page_order;
3926                 b_size = PAGE_SIZE << order;
3927         } else {
3928                 for (b_size = PAGE_SIZE, order = 0;
3929                      order < ST_MAX_ORDER &&
3930                              max_segs * (PAGE_SIZE << order) < new_size;
3931                      order++, b_size *= 2)
3932                         ;  /* empty */
3933                 STbuffer->reserved_page_order = order;
3934         }
3935         if (max_segs * (PAGE_SIZE << order) < new_size) {
3936                 if (order == ST_MAX_ORDER)
3937                         return 0;
3938                 normalize_buffer(STbuffer);
3939                 return enlarge_buffer(STbuffer, new_size, need_dma);
3940         }
3941
3942         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3943              segs < max_segs && got < new_size;) {
3944                 struct page *page;
3945
3946                 page = alloc_pages(priority, order);
3947                 if (!page) {
3948                         DEB(STbuffer->buffer_size = got);
3949                         normalize_buffer(STbuffer);
3950                         return 0;
3951                 }
3952
3953                 STbuffer->frp_segs += 1;
3954                 got += b_size;
3955                 STbuffer->buffer_size = got;
3956                 STbuffer->reserved_pages[segs] = page;
3957                 segs++;
3958         }
3959         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3960
3961         return 1;
3962 }
3963
3964
3965 /* Make sure that no data from previous user is in the internal buffer */
3966 static void clear_buffer(struct st_buffer * st_bp)
3967 {
3968         int i;
3969
3970         for (i=0; i < st_bp->frp_segs; i++)
3971                 memset(page_address(st_bp->reserved_pages[i]), 0,
3972                        PAGE_SIZE << st_bp->reserved_page_order);
3973         st_bp->cleared = 1;
3974 }
3975
3976
3977 /* Release the extra buffer */
3978 static void normalize_buffer(struct st_buffer * STbuffer)
3979 {
3980         int i, order = STbuffer->reserved_page_order;
3981
3982         for (i = 0; i < STbuffer->frp_segs; i++) {
3983                 __free_pages(STbuffer->reserved_pages[i], order);
3984                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3985         }
3986         STbuffer->frp_segs = 0;
3987         STbuffer->sg_segs = 0;
3988         STbuffer->reserved_page_order = 0;
3989         STbuffer->map_data.offset = 0;
3990 }
3991
3992
3993 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3994    negative error code. */
3995 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3996 {
3997         int i, cnt, res, offset;
3998         int length = PAGE_SIZE << st_bp->reserved_page_order;
3999
4000         for (i = 0, offset = st_bp->buffer_bytes;
4001              i < st_bp->frp_segs && offset >= length; i++)
4002                 offset -= length;
4003         if (i == st_bp->frp_segs) {     /* Should never happen */
4004                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4005                 return (-EIO);
4006         }
4007         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4008                 struct page *page = st_bp->reserved_pages[i];
4009                 cnt = length - offset < do_count ? length - offset : do_count;
4010                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4011                 if (res)
4012                         return (-EFAULT);
4013                 do_count -= cnt;
4014                 st_bp->buffer_bytes += cnt;
4015                 ubp += cnt;
4016                 offset = 0;
4017         }
4018         if (do_count) /* Should never happen */
4019                 return (-EIO);
4020
4021         return 0;
4022 }
4023
4024
4025 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4026    negative error code. */
4027 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4028 {
4029         int i, cnt, res, offset;
4030         int length = PAGE_SIZE << st_bp->reserved_page_order;
4031
4032         for (i = 0, offset = st_bp->read_pointer;
4033              i < st_bp->frp_segs && offset >= length; i++)
4034                 offset -= length;
4035         if (i == st_bp->frp_segs) {     /* Should never happen */
4036                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4037                 return (-EIO);
4038         }
4039         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4040                 struct page *page = st_bp->reserved_pages[i];
4041                 cnt = length - offset < do_count ? length - offset : do_count;
4042                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4043                 if (res)
4044                         return (-EFAULT);
4045                 do_count -= cnt;
4046                 st_bp->buffer_bytes -= cnt;
4047                 st_bp->read_pointer += cnt;
4048                 ubp += cnt;
4049                 offset = 0;
4050         }
4051         if (do_count) /* Should never happen */
4052                 return (-EIO);
4053
4054         return 0;
4055 }
4056
4057
4058 /* Move data towards start of buffer */
4059 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4060 {
4061         int src_seg, dst_seg, src_offset = 0, dst_offset;
4062         int count, total;
4063         int length = PAGE_SIZE << st_bp->reserved_page_order;
4064
4065         if (offset == 0)
4066                 return;
4067
4068         total=st_bp->buffer_bytes - offset;
4069         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4070                 src_offset = offset;
4071                 if (src_offset < length)
4072                         break;
4073                 offset -= length;
4074         }
4075
4076         st_bp->buffer_bytes = st_bp->read_pointer = total;
4077         for (dst_seg=dst_offset=0; total > 0; ) {
4078                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4079                 struct page *spage = st_bp->reserved_pages[src_seg];
4080
4081                 count = min(length - dst_offset, length - src_offset);
4082                 memmove(page_address(dpage) + dst_offset,
4083                         page_address(spage) + src_offset, count);
4084                 src_offset += count;
4085                 if (src_offset >= length) {
4086                         src_seg++;
4087                         src_offset = 0;
4088                 }
4089                 dst_offset += count;
4090                 if (dst_offset >= length) {
4091                         dst_seg++;
4092                         dst_offset = 0;
4093                 }
4094                 total -= count;
4095         }
4096 }
4097
4098 /* Validate the options from command line or module parameters */
4099 static void validate_options(void)
4100 {
4101         if (buffer_kbs > 0)
4102                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4103         if (max_sg_segs >= ST_FIRST_SG)
4104                 st_max_sg_segs = max_sg_segs;
4105 }
4106
4107 #ifndef MODULE
4108 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4109  */
4110 static int __init st_setup(char *str)
4111 {
4112         int i, len, ints[5];
4113         char *stp;
4114
4115         stp = get_options(str, ARRAY_SIZE(ints), ints);
4116
4117         if (ints[0] > 0) {
4118                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4119                         if (parms[i].val)
4120                                 *parms[i].val = ints[i + 1];
4121         } else {
4122                 while (stp != NULL) {
4123                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4124                                 len = strlen(parms[i].name);
4125                                 if (!strncmp(stp, parms[i].name, len) &&
4126                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4127                                         if (parms[i].val)
4128                                                 *parms[i].val =
4129                                                         simple_strtoul(stp + len + 1, NULL, 0);
4130                                         else
4131                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4132                                                        parms[i].name);
4133                                         break;
4134                                 }
4135                         }
4136                         if (i >= ARRAY_SIZE(parms))
4137                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4138                                         stp);
4139                         stp = strchr(stp, ',');
4140                         if (stp)
4141                                 stp++;
4142                 }
4143         }
4144
4145         validate_options();
4146
4147         return 1;
4148 }
4149
4150 __setup("st=", st_setup);
4151
4152 #endif
4153
4154 static const struct file_operations st_fops =
4155 {
4156         .owner =        THIS_MODULE,
4157         .read =         st_read,
4158         .write =        st_write,
4159         .unlocked_ioctl = st_ioctl,
4160 #ifdef CONFIG_COMPAT
4161         .compat_ioctl = st_compat_ioctl,
4162 #endif
4163         .open =         st_open,
4164         .flush =        st_flush,
4165         .release =      st_release,
4166         .llseek =       noop_llseek,
4167 };
4168
4169 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4170 {
4171         int i, error;
4172         dev_t cdev_devno;
4173         struct cdev *cdev;
4174         struct device *dev;
4175         struct st_modedef *STm = &(tape->modes[mode]);
4176         char name[10];
4177         int dev_num = tape->index;
4178
4179         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4180
4181         cdev = cdev_alloc();
4182         if (!cdev) {
4183                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4184                 error = -ENOMEM;
4185                 goto out;
4186         }
4187         cdev->owner = THIS_MODULE;
4188         cdev->ops = &st_fops;
4189         STm->cdevs[rew] = cdev;
4190
4191         error = cdev_add(cdev, cdev_devno, 1);
4192         if (error) {
4193                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4194                        rew ? "non" : "auto", mode);
4195                 pr_err("st%d: Device not attached.\n", dev_num);
4196                 goto out_free;
4197         }
4198
4199         i = mode << (4 - ST_NBR_MODE_BITS);
4200         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4201                  tape->disk->disk_name, st_formats[i]);
4202
4203         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4204                             cdev_devno, &tape->modes[mode], "%s", name);
4205         if (IS_ERR(dev)) {
4206                 pr_err("st%d: device_create failed\n", dev_num);
4207                 error = PTR_ERR(dev);
4208                 goto out_free;
4209         }
4210
4211         STm->devs[rew] = dev;
4212
4213         return 0;
4214 out_free:
4215         cdev_del(STm->cdevs[rew]);
4216 out:
4217         STm->cdevs[rew] = NULL;
4218         STm->devs[rew] = NULL;
4219         return error;
4220 }
4221
4222 static int create_cdevs(struct scsi_tape *tape)
4223 {
4224         int mode, error;
4225         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4226                 error = create_one_cdev(tape, mode, 0);
4227                 if (error)
4228                         return error;
4229                 error = create_one_cdev(tape, mode, 1);
4230                 if (error)
4231                         return error;
4232         }
4233
4234         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4235                                  &tape->modes[0].devs[0]->kobj, "tape");
4236 }
4237
4238 static void remove_cdevs(struct scsi_tape *tape)
4239 {
4240         int mode, rew;
4241         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4242         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4243                 struct st_modedef *STm = &(tape->modes[mode]);
4244                 for (rew = 0; rew < 2; rew++) {
4245                         if (STm->cdevs[rew])
4246                                 cdev_del(STm->cdevs[rew]);
4247                         if (STm->devs[rew])
4248                                 device_unregister(STm->devs[rew]);
4249                 }
4250         }
4251 }
4252
4253 static int st_probe(struct device *dev)
4254 {
4255         struct scsi_device *SDp = to_scsi_device(dev);
4256         struct gendisk *disk = NULL;
4257         struct scsi_tape *tpnt = NULL;
4258         struct st_modedef *STm;
4259         struct st_partstat *STps;
4260         struct st_buffer *buffer;
4261         int i, error;
4262         char *stp;
4263
4264         if (SDp->type != TYPE_TAPE)
4265                 return -ENODEV;
4266         if ((stp = st_incompatible(SDp))) {
4267                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4268                 sdev_printk(KERN_INFO, SDp,
4269                             "st: The suggested driver is %s.\n", stp);
4270                 return -ENODEV;
4271         }
4272
4273         scsi_autopm_get_device(SDp);
4274         i = queue_max_segments(SDp->request_queue);
4275         if (st_max_sg_segs < i)
4276                 i = st_max_sg_segs;
4277         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4278         if (buffer == NULL) {
4279                 sdev_printk(KERN_ERR, SDp,
4280                             "st: Can't allocate new tape buffer. "
4281                             "Device not attached.\n");
4282                 goto out;
4283         }
4284
4285         disk = alloc_disk(1);
4286         if (!disk) {
4287                 sdev_printk(KERN_ERR, SDp,
4288                             "st: out of memory. Device not attached.\n");
4289                 goto out_buffer_free;
4290         }
4291
4292         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4293         if (tpnt == NULL) {
4294                 sdev_printk(KERN_ERR, SDp,
4295                             "st: Can't allocate device descriptor.\n");
4296                 goto out_put_disk;
4297         }
4298         kref_init(&tpnt->kref);
4299         tpnt->disk = disk;
4300         disk->private_data = &tpnt->driver;
4301         disk->queue = SDp->request_queue;
4302         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4303          * take queue reference that release_disk() expects. */
4304         if (!blk_get_queue(disk->queue))
4305                 goto out_put_disk;
4306         tpnt->driver = &st_template;
4307
4308         tpnt->device = SDp;
4309         if (SDp->scsi_level <= 2)
4310                 tpnt->tape_type = MT_ISSCSI1;
4311         else
4312                 tpnt->tape_type = MT_ISSCSI2;
4313
4314         tpnt->buffer = buffer;
4315         tpnt->buffer->last_SRpnt = NULL;
4316
4317         tpnt->inited = 0;
4318         tpnt->dirty = 0;
4319         tpnt->in_use = 0;
4320         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4321         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4322         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4323         tpnt->density = 0;
4324         tpnt->do_auto_lock = ST_AUTO_LOCK;
4325         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4326         tpnt->can_partitions = 0;
4327         tpnt->two_fm = ST_TWO_FM;
4328         tpnt->fast_mteom = ST_FAST_MTEOM;
4329         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4330         tpnt->sili = ST_SILI;
4331         tpnt->immediate = ST_NOWAIT;
4332         tpnt->immediate_filemark = 0;
4333         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4334         tpnt->partition = 0;
4335         tpnt->new_partition = 0;
4336         tpnt->nbr_partitions = 0;
4337         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4338         tpnt->long_timeout = ST_LONG_TIMEOUT;
4339         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4340
4341         for (i = 0; i < ST_NBR_MODES; i++) {
4342                 STm = &(tpnt->modes[i]);
4343                 STm->defined = 0;
4344                 STm->sysv = ST_SYSV;
4345                 STm->defaults_for_writes = 0;
4346                 STm->do_async_writes = ST_ASYNC_WRITES;
4347                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4348                 STm->do_read_ahead = ST_READ_AHEAD;
4349                 STm->default_compression = ST_DONT_TOUCH;
4350                 STm->default_blksize = (-1);    /* No forced size */
4351                 STm->default_density = (-1);    /* No forced density */
4352                 STm->tape = tpnt;
4353         }
4354
4355         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4356                 STps = &(tpnt->ps[i]);
4357                 STps->rw = ST_IDLE;
4358                 STps->eof = ST_NOEOF;
4359                 STps->at_sm = 0;
4360                 STps->last_block_valid = 0;
4361                 STps->drv_block = (-1);
4362                 STps->drv_file = (-1);
4363         }
4364
4365         tpnt->current_mode = 0;
4366         tpnt->modes[0].defined = 1;
4367
4368         tpnt->density_changed = tpnt->compression_changed =
4369             tpnt->blksize_changed = 0;
4370         mutex_init(&tpnt->lock);
4371
4372         idr_preload(GFP_KERNEL);
4373         spin_lock(&st_index_lock);
4374         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4375         spin_unlock(&st_index_lock);
4376         idr_preload_end();
4377         if (error < 0) {
4378                 pr_warn("st: idr allocation failed: %d\n", error);
4379                 goto out_put_queue;
4380         }
4381         tpnt->index = error;
4382         sprintf(disk->disk_name, "st%d", tpnt->index);
4383         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4384         if (tpnt->stats == NULL) {
4385                 sdev_printk(KERN_ERR, SDp,
4386                             "st: Can't allocate statistics.\n");
4387                 goto out_idr_remove;
4388         }
4389
4390         dev_set_drvdata(dev, tpnt);
4391
4392
4393         error = create_cdevs(tpnt);
4394         if (error)
4395                 goto out_remove_devs;
4396         scsi_autopm_put_device(SDp);
4397
4398         sdev_printk(KERN_NOTICE, SDp,
4399                     "Attached scsi tape %s\n", tape_name(tpnt));
4400         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4401                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4402                     queue_dma_alignment(SDp->request_queue) + 1);
4403
4404         return 0;
4405
4406 out_remove_devs:
4407         remove_cdevs(tpnt);
4408         kfree(tpnt->stats);
4409 out_idr_remove:
4410         spin_lock(&st_index_lock);
4411         idr_remove(&st_index_idr, tpnt->index);
4412         spin_unlock(&st_index_lock);
4413 out_put_queue:
4414         blk_put_queue(disk->queue);
4415 out_put_disk:
4416         put_disk(disk);
4417         kfree(tpnt);
4418 out_buffer_free:
4419         kfree(buffer);
4420 out:
4421         scsi_autopm_put_device(SDp);
4422         return -ENODEV;
4423 };
4424
4425
4426 static int st_remove(struct device *dev)
4427 {
4428         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4429         int index = tpnt->index;
4430
4431         scsi_autopm_get_device(to_scsi_device(dev));
4432         remove_cdevs(tpnt);
4433
4434         mutex_lock(&st_ref_mutex);
4435         kref_put(&tpnt->kref, scsi_tape_release);
4436         mutex_unlock(&st_ref_mutex);
4437         spin_lock(&st_index_lock);
4438         idr_remove(&st_index_idr, index);
4439         spin_unlock(&st_index_lock);
4440         return 0;
4441 }
4442
4443 /**
4444  *      scsi_tape_release - Called to free the Scsi_Tape structure
4445  *      @kref: pointer to embedded kref
4446  *
4447  *      st_ref_mutex must be held entering this routine.  Because it is
4448  *      called on last put, you should always use the scsi_tape_get()
4449  *      scsi_tape_put() helpers which manipulate the semaphore directly
4450  *      and never do a direct kref_put().
4451  **/
4452 static void scsi_tape_release(struct kref *kref)
4453 {
4454         struct scsi_tape *tpnt = to_scsi_tape(kref);
4455         struct gendisk *disk = tpnt->disk;
4456
4457         tpnt->device = NULL;
4458
4459         if (tpnt->buffer) {
4460                 normalize_buffer(tpnt->buffer);
4461                 kfree(tpnt->buffer->reserved_pages);
4462                 kfree(tpnt->buffer);
4463         }
4464
4465         disk->private_data = NULL;
4466         put_disk(disk);
4467         kfree(tpnt->stats);
4468         kfree(tpnt);
4469         return;
4470 }
4471
4472 static struct class st_sysfs_class = {
4473         .name = "scsi_tape",
4474         .dev_groups = st_dev_groups,
4475 };
4476
4477 static int __init init_st(void)
4478 {
4479         int err;
4480
4481         validate_options();
4482
4483         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4484                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4485
4486         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4487         if (debugging) {
4488                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4489                         debugging);
4490         }
4491
4492         err = class_register(&st_sysfs_class);
4493         if (err) {
4494                 pr_err("Unable register sysfs class for SCSI tapes\n");
4495                 return err;
4496         }
4497
4498         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4499                                      ST_MAX_TAPE_ENTRIES, "st");
4500         if (err) {
4501                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4502                        SCSI_TAPE_MAJOR);
4503                 goto err_class;
4504         }
4505
4506         err = scsi_register_driver(&st_template.gendrv);
4507         if (err)
4508                 goto err_chrdev;
4509
4510         return 0;
4511
4512 err_chrdev:
4513         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4514                                  ST_MAX_TAPE_ENTRIES);
4515 err_class:
4516         class_unregister(&st_sysfs_class);
4517         return err;
4518 }
4519
4520 static void __exit exit_st(void)
4521 {
4522         scsi_unregister_driver(&st_template.gendrv);
4523         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4524                                  ST_MAX_TAPE_ENTRIES);
4525         class_unregister(&st_sysfs_class);
4526         idr_destroy(&st_index_idr);
4527         printk(KERN_INFO "st: Unloaded.\n");
4528 }
4529
4530 module_init(init_st);
4531 module_exit(exit_st);
4532
4533
4534 /* The sysfs driver interface. Read-only at the moment */
4535 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4536 {
4537         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4538 }
4539 static DRIVER_ATTR_RO(try_direct_io);
4540
4541 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4542 {
4543         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4544 }
4545 static DRIVER_ATTR_RO(fixed_buffer_size);
4546
4547 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4548 {
4549         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4550 }
4551 static DRIVER_ATTR_RO(max_sg_segs);
4552
4553 static ssize_t version_show(struct device_driver *ddd, char *buf)
4554 {
4555         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4556 }
4557 static DRIVER_ATTR_RO(version);
4558
4559 #if DEBUG
4560 static ssize_t debug_flag_store(struct device_driver *ddp,
4561         const char *buf, size_t count)
4562 {
4563 /* We only care what the first byte of the data is the rest is unused.
4564  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4565  * other values have -EINVAL returned if they are passed in.
4566  */
4567         if (count > 0) {
4568                 if (buf[0] == '0') {
4569                         debugging = NO_DEBUG;
4570                         return count;
4571                 } else if (buf[0] == '1') {
4572                         debugging = 1;
4573                         return count;
4574                 }
4575         }
4576         return -EINVAL;
4577 }
4578
4579 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4580 {
4581         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4582 }
4583 static DRIVER_ATTR_RW(debug_flag);
4584 #endif
4585
4586 static struct attribute *st_drv_attrs[] = {
4587         &driver_attr_try_direct_io.attr,
4588         &driver_attr_fixed_buffer_size.attr,
4589         &driver_attr_max_sg_segs.attr,
4590         &driver_attr_version.attr,
4591 #if DEBUG
4592         &driver_attr_debug_flag.attr,
4593 #endif
4594         NULL,
4595 };
4596 ATTRIBUTE_GROUPS(st_drv);
4597
4598 /* The sysfs simple class interface */
4599 static ssize_t
4600 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4601 {
4602         struct st_modedef *STm = dev_get_drvdata(dev);
4603         ssize_t l = 0;
4604
4605         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4606         return l;
4607 }
4608 static DEVICE_ATTR_RO(defined);
4609
4610 static ssize_t
4611 default_blksize_show(struct device *dev, struct device_attribute *attr,
4612                      char *buf)
4613 {
4614         struct st_modedef *STm = dev_get_drvdata(dev);
4615         ssize_t l = 0;
4616
4617         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4618         return l;
4619 }
4620 static DEVICE_ATTR_RO(default_blksize);
4621
4622 static ssize_t
4623 default_density_show(struct device *dev, struct device_attribute *attr,
4624                      char *buf)
4625 {
4626         struct st_modedef *STm = dev_get_drvdata(dev);
4627         ssize_t l = 0;
4628         char *fmt;
4629
4630         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4631         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4632         return l;
4633 }
4634 static DEVICE_ATTR_RO(default_density);
4635
4636 static ssize_t
4637 default_compression_show(struct device *dev, struct device_attribute *attr,
4638                          char *buf)
4639 {
4640         struct st_modedef *STm = dev_get_drvdata(dev);
4641         ssize_t l = 0;
4642
4643         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4644         return l;
4645 }
4646 static DEVICE_ATTR_RO(default_compression);
4647
4648 static ssize_t
4649 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4650 {
4651         struct st_modedef *STm = dev_get_drvdata(dev);
4652         struct scsi_tape *STp = STm->tape;
4653         int options;
4654         ssize_t l = 0;
4655
4656         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4657         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4658         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4659         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4660         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4661         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4662         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4663         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4664         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4665         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4666         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4667         options |= STm->sysv ? MT_ST_SYSV : 0;
4668         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4669         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4670         options |= STp->sili ? MT_ST_SILI : 0;
4671
4672         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4673         return l;
4674 }
4675 static DEVICE_ATTR_RO(options);
4676
4677 /* Support for tape stats */
4678
4679 /**
4680  * read_cnt_show - return read count - count of reads made from tape drive
4681  * @dev: struct device
4682  * @attr: attribute structure
4683  * @buf: buffer to return formatted data in
4684  */
4685 static ssize_t read_cnt_show(struct device *dev,
4686         struct device_attribute *attr, char *buf)
4687 {
4688         struct st_modedef *STm = dev_get_drvdata(dev);
4689
4690         return sprintf(buf, "%lld",
4691                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4692 }
4693 static DEVICE_ATTR_RO(read_cnt);
4694
4695 /**
4696  * read_byte_cnt_show - return read byte count - tape drives
4697  * may use blocks less than 512 bytes this gives the raw byte count of
4698  * of data read from the tape drive.
4699  * @dev: struct device
4700  * @attr: attribute structure
4701  * @buf: buffer to return formatted data in
4702  */
4703 static ssize_t read_byte_cnt_show(struct device *dev,
4704         struct device_attribute *attr, char *buf)
4705 {
4706         struct st_modedef *STm = dev_get_drvdata(dev);
4707
4708         return sprintf(buf, "%lld",
4709                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4710 }
4711 static DEVICE_ATTR_RO(read_byte_cnt);
4712
4713 /**
4714  * read_us_show - return read us - overall time spent waiting on reads in ns.
4715  * @dev: struct device
4716  * @attr: attribute structure
4717  * @buf: buffer to return formatted data in
4718  */
4719 static ssize_t read_ns_show(struct device *dev,
4720         struct device_attribute *attr, char *buf)
4721 {
4722         struct st_modedef *STm = dev_get_drvdata(dev);
4723
4724         return sprintf(buf, "%lld",
4725                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4726 }
4727 static DEVICE_ATTR_RO(read_ns);
4728
4729 /**
4730  * write_cnt_show - write count - number of user calls
4731  * to write(2) that have written data to tape.
4732  * @dev: struct device
4733  * @attr: attribute structure
4734  * @buf: buffer to return formatted data in
4735  */
4736 static ssize_t write_cnt_show(struct device *dev,
4737         struct device_attribute *attr, char *buf)
4738 {
4739         struct st_modedef *STm = dev_get_drvdata(dev);
4740
4741         return sprintf(buf, "%lld",
4742                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4743 }
4744 static DEVICE_ATTR_RO(write_cnt);
4745
4746 /**
4747  * write_byte_cnt_show - write byte count - raw count of
4748  * bytes written to tape.
4749  * @dev: struct device
4750  * @attr: attribute structure
4751  * @buf: buffer to return formatted data in
4752  */
4753 static ssize_t write_byte_cnt_show(struct device *dev,
4754         struct device_attribute *attr, char *buf)
4755 {
4756         struct st_modedef *STm = dev_get_drvdata(dev);
4757
4758         return sprintf(buf, "%lld",
4759                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4760 }
4761 static DEVICE_ATTR_RO(write_byte_cnt);
4762
4763 /**
4764  * write_ns_show - write ns - number of nanoseconds waiting on write
4765  * requests to complete.
4766  * @dev: struct device
4767  * @attr: attribute structure
4768  * @buf: buffer to return formatted data in
4769  */
4770 static ssize_t write_ns_show(struct device *dev,
4771         struct device_attribute *attr, char *buf)
4772 {
4773         struct st_modedef *STm = dev_get_drvdata(dev);
4774
4775         return sprintf(buf, "%lld",
4776                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4777 }
4778 static DEVICE_ATTR_RO(write_ns);
4779
4780 /**
4781  * in_flight_show - number of I/Os currently in flight -
4782  * in most cases this will be either 0 or 1. It may be higher if someone
4783  * has also issued other SCSI commands such as via an ioctl.
4784  * @dev: struct device
4785  * @attr: attribute structure
4786  * @buf: buffer to return formatted data in
4787  */
4788 static ssize_t in_flight_show(struct device *dev,
4789         struct device_attribute *attr, char *buf)
4790 {
4791         struct st_modedef *STm = dev_get_drvdata(dev);
4792
4793         return sprintf(buf, "%lld",
4794                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4795 }
4796 static DEVICE_ATTR_RO(in_flight);
4797
4798 /**
4799  * io_ns_show - io wait ns - this is the number of ns spent
4800  * waiting on all I/O to complete. This includes tape movement commands
4801  * such as rewinding, seeking to end of file or tape, it also includes
4802  * read and write. To determine the time spent on tape movement
4803  * subtract the read and write ns from this value.
4804  * @dev: struct device
4805  * @attr: attribute structure
4806  * @buf: buffer to return formatted data in
4807  */
4808 static ssize_t io_ns_show(struct device *dev,
4809         struct device_attribute *attr, char *buf)
4810 {
4811         struct st_modedef *STm = dev_get_drvdata(dev);
4812
4813         return sprintf(buf, "%lld",
4814                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4815 }
4816 static DEVICE_ATTR_RO(io_ns);
4817
4818 /**
4819  * other_cnt_show - other io count - this is the number of
4820  * I/O requests other than read and write requests.
4821  * Typically these are tape movement requests but will include driver
4822  * tape movement. This includes only requests issued by the st driver.
4823  * @dev: struct device
4824  * @attr: attribute structure
4825  * @buf: buffer to return formatted data in
4826  */
4827 static ssize_t other_cnt_show(struct device *dev,
4828         struct device_attribute *attr, char *buf)
4829 {
4830         struct st_modedef *STm = dev_get_drvdata(dev);
4831
4832         return sprintf(buf, "%lld",
4833                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4834 }
4835 static DEVICE_ATTR_RO(other_cnt);
4836
4837 /**
4838  * resid_cnt_show - A count of the number of times we get a residual
4839  * count - this should indicate someone issuing reads larger than the
4840  * block size on tape.
4841  * @dev: struct device
4842  * @attr: attribute structure
4843  * @buf: buffer to return formatted data in
4844  */
4845 static ssize_t resid_cnt_show(struct device *dev,
4846         struct device_attribute *attr, char *buf)
4847 {
4848         struct st_modedef *STm = dev_get_drvdata(dev);
4849
4850         return sprintf(buf, "%lld",
4851                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4852 }
4853 static DEVICE_ATTR_RO(resid_cnt);
4854
4855 static struct attribute *st_dev_attrs[] = {
4856         &dev_attr_defined.attr,
4857         &dev_attr_default_blksize.attr,
4858         &dev_attr_default_density.attr,
4859         &dev_attr_default_compression.attr,
4860         &dev_attr_options.attr,
4861         NULL,
4862 };
4863
4864 static struct attribute *st_stats_attrs[] = {
4865         &dev_attr_read_cnt.attr,
4866         &dev_attr_read_byte_cnt.attr,
4867         &dev_attr_read_ns.attr,
4868         &dev_attr_write_cnt.attr,
4869         &dev_attr_write_byte_cnt.attr,
4870         &dev_attr_write_ns.attr,
4871         &dev_attr_in_flight.attr,
4872         &dev_attr_io_ns.attr,
4873         &dev_attr_other_cnt.attr,
4874         &dev_attr_resid_cnt.attr,
4875         NULL,
4876 };
4877
4878 static struct attribute_group stats_group = {
4879         .name = "stats",
4880         .attrs = st_stats_attrs,
4881 };
4882
4883 static struct attribute_group st_group = {
4884         .attrs = st_dev_attrs,
4885 };
4886
4887 static const struct attribute_group *st_dev_groups[] = {
4888         &st_group,
4889         &stats_group,
4890         NULL,
4891 };
4892
4893 /* The following functions may be useful for a larger audience. */
4894 static int sgl_map_user_pages(struct st_buffer *STbp,
4895                               const unsigned int max_pages, unsigned long uaddr,
4896                               size_t count, int rw)
4897 {
4898         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4899         unsigned long start = uaddr >> PAGE_SHIFT;
4900         const int nr_pages = end - start;
4901         int res, i, j;
4902         struct page **pages;
4903         struct rq_map_data *mdata = &STbp->map_data;
4904
4905         /* User attempted Overflow! */
4906         if ((uaddr + count) < uaddr)
4907                 return -EINVAL;
4908
4909         /* Too big */
4910         if (nr_pages > max_pages)
4911                 return -ENOMEM;
4912
4913         /* Hmm? */
4914         if (count == 0)
4915                 return 0;
4916
4917         if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4918                 return -ENOMEM;
4919
4920         /* Try to fault in all of the necessary pages */
4921         /* rw==READ means read from drive, write into memory area */
4922         res = get_user_pages_unlocked(
4923                 uaddr,
4924                 nr_pages,
4925                 rw == READ,
4926                 0, /* don't force */
4927                 pages);
4928
4929         /* Errors and no page mapped should return here */
4930         if (res < nr_pages)
4931                 goto out_unmap;
4932
4933         for (i=0; i < nr_pages; i++) {
4934                 /* FIXME: flush superflous for rw==READ,
4935                  * probably wrong function for rw==WRITE
4936                  */
4937                 flush_dcache_page(pages[i]);
4938         }
4939
4940         mdata->offset = uaddr & ~PAGE_MASK;
4941         STbp->mapped_pages = pages;
4942
4943         return nr_pages;
4944  out_unmap:
4945         if (res > 0) {
4946                 for (j=0; j < res; j++)
4947                         put_page(pages[j]);
4948                 res = 0;
4949         }
4950         kfree(pages);
4951         return res;
4952 }
4953
4954
4955 /* And unmap them... */
4956 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4957                                 const unsigned int nr_pages, int dirtied)
4958 {
4959         int i;
4960
4961         for (i=0; i < nr_pages; i++) {
4962                 struct page *page = STbp->mapped_pages[i];
4963
4964                 if (dirtied)
4965                         SetPageDirty(page);
4966                 /* FIXME: cache flush missing for rw==READ
4967                  * FIXME: call the correct reference counting function
4968                  */
4969                 put_page(page);
4970         }
4971         kfree(STbp->mapped_pages);
4972         STbp->mapped_pages = NULL;
4973
4974         return 0;
4975 }