drivers/scsi/sg.c

   1 /*
   2  *  History:
   3  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
   4  *           to allow user process control of SCSI devices.
   5  *  Development Sponsored by Killy Corp. NY NY
   6  *
   7  * Original driver (sg.c):
   8  *        Copyright (C) 1992 Lawrence Foard
   9  * Version 2 and 3 extensions to driver:
  10  *        Copyright (C) 1998 - 2014 Douglas Gilbert
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2, or (at your option)
  15  * any later version.
  16  *
  17  */
  18
  19 static int sg_version_num = 30536;      /* 2 digits for each component */
  20 #define SG_VERSION_STR "3.5.36"
  21
  22 /*
  23  *  D. P. Gilbert (dgilbert@interlog.com), notes:
  24  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
  25  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
  26  *        (otherwise the macros compile to empty statements).
  27  *
  28  */
  29 #include <linux/module.h>
  30
  31 #include <linux/fs.h>
  32 #include <linux/kernel.h>
  33 #include <linux/sched.h>
  34 #include <linux/string.h>
  35 #include <linux/mm.h>
  36 #include <linux/aio.h>
  37 #include <linux/errno.h>
  38 #include <linux/mtio.h>
  39 #include <linux/ioctl.h>
  40 #include <linux/slab.h>
  41 #include <linux/fcntl.h>
  42 #include <linux/init.h>
  43 #include <linux/poll.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/cdev.h>
  46 #include <linux/idr.h>
  47 #include <linux/seq_file.h>
  48 #include <linux/blkdev.h>
  49 #include <linux/delay.h>
  50 #include <linux/blktrace_api.h>
  51 #include <linux/mutex.h>
  52 #include <linux/atomic.h>
  53 #include <linux/ratelimit.h>
  54
  55 #include "scsi.h"
  56 #include <scsi/scsi_dbg.h>
  57 #include <scsi/scsi_host.h>
  58 #include <scsi/scsi_driver.h>
  59 #include <scsi/scsi_ioctl.h>
  60 #include <scsi/sg.h>
  61
  62 #include "scsi_logging.h"
  63
  64 #ifdef CONFIG_SCSI_PROC_FS
  65 #include <linux/proc_fs.h>
  66 static char *sg_version_date = "20140603";
  67
  68 static int sg_proc_init(void);
  69 static void sg_proc_cleanup(void);
  70 #endif
  71
  72 #define SG_ALLOW_DIO_DEF 0
  73
  74 #define SG_MAX_DEVS 32768
  75
  76 /* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
  77  * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
  78  * than 16 bytes are "variable length" whose length is a multiple of 4
  79  */
  80 #define SG_MAX_CDB_SIZE 252
  81
  82 /*
  83  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
  84  * Then when using 32 bit integers x * m may overflow during the calculation.
  85  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
  86  * calculates the same, but prevents the overflow when both m and d
  87  * are "small" numbers (like HZ and USER_HZ).
  88  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
  89  * in 32 bits.
  90  */
  91 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
  92
  93 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
  94
  95 int sg_big_buff = SG_DEF_RESERVED_SIZE;
  96 /* N.B. This variable is readable and writeable via
  97    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
  98    of this size (or less if there is not enough memory) will be reserved
  99    for use by this file descriptor. [Deprecated usage: this variable is also
 100    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
 101    the kernel (i.e. it is not a module).] */
 102 static int def_reserved_size = -1;      /* picks up init parameter */
 103 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
 104
 105 static int scatter_elem_sz = SG_SCATTER_SZ;
 106 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
 107
 108 #define SG_SECTOR_SZ 512
 109
 110 static int sg_add_device(struct device *, struct class_interface *);
 111 static void sg_remove_device(struct device *, struct class_interface *);
 112
 113 static DEFINE_IDR(sg_index_idr);
 114 static DEFINE_RWLOCK(sg_index_lock);    /* Also used to lock
 115                                                            file descriptor list for device */
 116
 117 static struct class_interface sg_interface = {
 118         .add_dev        = sg_add_device,
 119         .remove_dev     = sg_remove_device,
 120 };
 121
 122 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
 123         unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
 124         unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
 125         unsigned bufflen;       /* Size of (aggregate) data buffer */
 126         struct page **pages;
 127         int page_order;
 128         char dio_in_use;        /* 0->indirect IO (or mmap), 1->dio */
 129         unsigned char cmd_opcode; /* first byte of command */
 130 } Sg_scatter_hold;
 131
 132 struct sg_device;               /* forward declarations */
 133 struct sg_fd;
 134
 135 typedef struct sg_request {     /* SG_MAX_QUEUE requests outstanding per file */
 136         struct sg_request *nextrp;      /* NULL -> tail request (slist) */
 137         struct sg_fd *parentfp; /* NULL -> not in use */
 138         Sg_scatter_hold data;   /* hold buffer, perhaps scatter list */
 139         sg_io_hdr_t header;     /* scsi command+info, see <scsi/sg.h> */
 140         unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
 141         char res_used;          /* 1 -> using reserve buffer, 0 -> not ... */
 142         char orphan;            /* 1 -> drop on sight, 0 -> normal */
 143         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
 144         /* done protected by rq_list_lock */
 145         char done;              /* 0->before bh, 1->before read, 2->read */
 146         struct request *rq;
 147         struct bio *bio;
 148         struct execute_work ew;
 149 } Sg_request;
 150
 151 typedef struct sg_fd {          /* holds the state of a file descriptor */
 152         struct list_head sfd_siblings;  /* protected by device's sfd_lock */
 153         struct sg_device *parentdp;     /* owning device */
 154         wait_queue_head_t read_wait;    /* queue read until command done */
 155         rwlock_t rq_list_lock;  /* protect access to list in req_arr */
 156         int timeout;            /* defaults to SG_DEFAULT_TIMEOUT      */
 157         int timeout_user;       /* defaults to SG_DEFAULT_TIMEOUT_USER */
 158         Sg_scatter_hold reserve;        /* buffer held for this file descriptor */
 159         unsigned save_scat_len; /* original length of trunc. scat. element */
 160         Sg_request *headrp;     /* head of request slist, NULL->empty */
 161         struct fasync_struct *async_qp; /* used by asynchronous notification */
 162         Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
 163         char low_dma;           /* as in parent but possibly overridden to 1 */
 164         char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
 165         char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
 166         unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
 167         char keep_orphan;       /* 0 -> drop orphan (def), 1 -> keep for read() */
 168         char mmap_called;       /* 0 -> mmap() never called on this fd */
 169         struct kref f_ref;
 170         struct execute_work ew;
 171 } Sg_fd;
 172
 173 typedef struct sg_device { /* holds the state of each scsi generic device */
 174         struct scsi_device *device;
 175         wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
 176         struct mutex open_rel_lock;     /* held when in open() or release() */
 177         int sg_tablesize;       /* adapter's max scatter-gather table size */
 178         u32 index;              /* device index number */
 179         struct list_head sfds;
 180         rwlock_t sfd_lock;      /* protect access to sfd list */
 181         atomic_t detaching;     /* 0->device usable, 1->device detaching */
 182         bool exclude;           /* 1->open(O_EXCL) succeeded and is active */
 183         int open_cnt;           /* count of opens (perhaps < num(sfds) ) */
 184         char sgdebug;           /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
 185         struct gendisk *disk;
 186         struct cdev * cdev;     /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
 187         struct kref d_ref;
 188 } Sg_device;
 189
 190 /* tasklet or soft irq callback */
 191 static void sg_rq_end_io(struct request *rq, int uptodate);
 192 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 193 static int sg_finish_rem_req(Sg_request * srp);
 194 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 195 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 196                            Sg_request * srp);
 197 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
 198                         const char __user *buf, size_t count, int blocking,
 199                         int read_only, int sg_io_owned, Sg_request **o_srp);
 200 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 201                            unsigned char *cmnd, int timeout, int blocking);
 202 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
 203 static void sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp);
 204 static void sg_build_reserve(Sg_fd * sfp, int req_size);
 205 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
 206 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
 207 static Sg_fd *sg_add_sfp(Sg_device * sdp);
 208 static void sg_remove_sfp(struct kref *);
 209 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
 210 static Sg_request *sg_add_request(Sg_fd * sfp);
 211 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 212 static int sg_res_in_use(Sg_fd * sfp);
 213 static Sg_device *sg_get_dev(int dev);
 214 static void sg_device_destroy(struct kref *kref);
 215
 216 #define SZ_SG_HEADER sizeof(struct sg_header)
 217 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
 218 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
 219 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
 220
 221 #define sg_printk(prefix, sdp, fmt, a...) \
 222         sdev_printk(prefix, (sdp)->device, "[%s] " fmt, \
 223                     (sdp)->disk->disk_name, ##a)
 224
 225 static int sg_allow_access(struct file *filp, unsigned char *cmd)
 226 {
 227         struct sg_fd *sfp = filp->private_data;
 228
 229         if (sfp->parentdp->device->type == TYPE_SCANNER)
 230                 return 0;
 231
 232         return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
 233 }
 234
 235 static int
 236 open_wait(Sg_device *sdp, int flags)
 237 {
 238         int retval = 0;
 239
 240         if (flags & O_EXCL) {
 241                 while (sdp->open_cnt > 0) {
 242                         mutex_unlock(&sdp->open_rel_lock);
 243                         retval = wait_event_interruptible(sdp->open_wait,
 244                                         (atomic_read(&sdp->detaching) ||
 245                                          !sdp->open_cnt));
 246                         mutex_lock(&sdp->open_rel_lock);
 247
 248                         if (retval) /* -ERESTARTSYS */
 249                                 return retval;
 250                         if (atomic_read(&sdp->detaching))
 251                                 return -ENODEV;
 252                 }
 253         } else {
 254                 while (sdp->exclude) {
 255                         mutex_unlock(&sdp->open_rel_lock);
 256                         retval = wait_event_interruptible(sdp->open_wait,
 257                                         (atomic_read(&sdp->detaching) ||
 258                                          !sdp->exclude));
 259                         mutex_lock(&sdp->open_rel_lock);
 260
 261                         if (retval) /* -ERESTARTSYS */
 262                                 return retval;
 263                         if (atomic_read(&sdp->detaching))
 264                                 return -ENODEV;
 265                 }
 266         }
 267
 268         return retval;
 269 }
 270
 271 /* Returns 0 on success, else a negated errno value */
 272 static int
 273 sg_open(struct inode *inode, struct file *filp)
 274 {
 275         int dev = iminor(inode);
 276         int flags = filp->f_flags;
 277         struct request_queue *q;
 278         Sg_device *sdp;
 279         Sg_fd *sfp;
 280         int retval;
 281
 282         nonseekable_open(inode, filp);
 283         if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
 284                 return -EPERM; /* Can't lock it with read only access */
 285         sdp = sg_get_dev(dev);
 286         if (IS_ERR(sdp))
 287                 return PTR_ERR(sdp);
 288
 289         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 290                                       "sg_open: flags=0x%x\n", flags));
 291
 292         /* This driver's module count bumped by fops_get in <linux/fs.h> */
 293         /* Prevent the device driver from vanishing while we sleep */
 294         retval = scsi_device_get(sdp->device);
 295         if (retval)
 296                 goto sg_put;
 297
 298         retval = scsi_autopm_get_device(sdp->device);
 299         if (retval)
 300                 goto sdp_put;
 301
 302         /* scsi_block_when_processing_errors() may block so bypass
 303          * check if O_NONBLOCK. Permits SCSI commands to be issued
 304          * during error recovery. Tread carefully. */
 305         if (!((flags & O_NONBLOCK) ||
 306               scsi_block_when_processing_errors(sdp->device))) {
 307                 retval = -ENXIO;
 308                 /* we are in error recovery for this device */
 309                 goto error_out;
 310         }
 311
 312         mutex_lock(&sdp->open_rel_lock);
 313         if (flags & O_NONBLOCK) {
 314                 if (flags & O_EXCL) {
 315                         if (sdp->open_cnt > 0) {
 316                                 retval = -EBUSY;
 317                                 goto error_mutex_locked;
 318                         }
 319                 } else {
 320                         if (sdp->exclude) {
 321                                 retval = -EBUSY;
 322                                 goto error_mutex_locked;
 323                         }
 324                 }
 325         } else {
 326                 retval = open_wait(sdp, flags);
 327                 if (retval) /* -ERESTARTSYS or -ENODEV */
 328                         goto error_mutex_locked;
 329         }
 330
 331         /* N.B. at this point we are holding the open_rel_lock */
 332         if (flags & O_EXCL)
 333                 sdp->exclude = true;
 334
 335         if (sdp->open_cnt < 1) {  /* no existing opens */
 336                 sdp->sgdebug = 0;
 337                 q = sdp->device->request_queue;
 338                 sdp->sg_tablesize = queue_max_segments(q);
 339         }
 340         sfp = sg_add_sfp(sdp);
 341         if (IS_ERR(sfp)) {
 342                 retval = PTR_ERR(sfp);
 343                 goto out_undo;
 344         }
 345
 346         filp->private_data = sfp;
 347         sdp->open_cnt++;
 348         mutex_unlock(&sdp->open_rel_lock);
 349
 350         retval = 0;
 351 sg_put:
 352         kref_put(&sdp->d_ref, sg_device_destroy);
 353         return retval;
 354
 355 out_undo:
 356         if (flags & O_EXCL) {
 357                 sdp->exclude = false;   /* undo if error */
 358                 wake_up_interruptible(&sdp->open_wait);
 359         }
 360 error_mutex_locked:
 361         mutex_unlock(&sdp->open_rel_lock);
 362 error_out:
 363         scsi_autopm_put_device(sdp->device);
 364 sdp_put:
 365         scsi_device_put(sdp->device);
 366         goto sg_put;
 367 }
 368
 369 /* Release resources associated with a successful sg_open()
 370  * Returns 0 on success, else a negated errno value */
 371 static int
 372 sg_release(struct inode *inode, struct file *filp)
 373 {
 374         Sg_device *sdp;
 375         Sg_fd *sfp;
 376
 377         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 378                 return -ENXIO;
 379         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
 380
 381         mutex_lock(&sdp->open_rel_lock);
 382         scsi_autopm_put_device(sdp->device);
 383         kref_put(&sfp->f_ref, sg_remove_sfp);
 384         sdp->open_cnt--;
 385
 386         /* possibly many open()s waiting on exlude clearing, start many;
 387          * only open(O_EXCL)s wait on 0==open_cnt so only start one */
 388         if (sdp->exclude) {
 389                 sdp->exclude = false;
 390                 wake_up_interruptible_all(&sdp->open_wait);
 391         } else if (0 == sdp->open_cnt) {
 392                 wake_up_interruptible(&sdp->open_wait);
 393         }
 394         mutex_unlock(&sdp->open_rel_lock);
 395         return 0;
 396 }
 397
 398 static ssize_t
 399 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
 400 {
 401         Sg_device *sdp;
 402         Sg_fd *sfp;
 403         Sg_request *srp;
 404         int req_pack_id = -1;
 405         sg_io_hdr_t *hp;
 406         struct sg_header *old_hdr = NULL;
 407         int retval = 0;
 408
 409         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 410                 return -ENXIO;
 411         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 412                                       "sg_read: count=%d\n", (int) count));
 413
 414         if (!access_ok(VERIFY_WRITE, buf, count))
 415                 return -EFAULT;
 416         if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
 417                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 418                 if (!old_hdr)
 419                         return -ENOMEM;
 420                 if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
 421                         retval = -EFAULT;
 422                         goto free_old_hdr;
 423                 }
 424                 if (old_hdr->reply_len < 0) {
 425                         if (count >= SZ_SG_IO_HDR) {
 426                                 sg_io_hdr_t *new_hdr;
 427                                 new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
 428                                 if (!new_hdr) {
 429                                         retval = -ENOMEM;
 430                                         goto free_old_hdr;
 431                                 }
 432                                 retval =__copy_from_user
 433                                     (new_hdr, buf, SZ_SG_IO_HDR);
 434                                 req_pack_id = new_hdr->pack_id;
 435                                 kfree(new_hdr);
 436                                 if (retval) {
 437                                         retval = -EFAULT;
 438                                         goto free_old_hdr;
 439                                 }
 440                         }
 441                 } else
 442                         req_pack_id = old_hdr->pack_id;
 443         }
 444         srp = sg_get_rq_mark(sfp, req_pack_id);
 445         if (!srp) {             /* now wait on packet to arrive */
 446                 if (atomic_read(&sdp->detaching)) {
 447                         retval = -ENODEV;
 448                         goto free_old_hdr;
 449                 }
 450                 if (filp->f_flags & O_NONBLOCK) {
 451                         retval = -EAGAIN;
 452                         goto free_old_hdr;
 453                 }
 454                 retval = wait_event_interruptible(sfp->read_wait,
 455                         (atomic_read(&sdp->detaching) ||
 456                         (srp = sg_get_rq_mark(sfp, req_pack_id))));
 457                 if (atomic_read(&sdp->detaching)) {
 458                         retval = -ENODEV;
 459                         goto free_old_hdr;
 460                 }
 461                 if (retval) {
 462                         /* -ERESTARTSYS as signal hit process */
 463                         goto free_old_hdr;
 464                 }
 465         }
 466         if (srp->header.interface_id != '\0') {
 467                 retval = sg_new_read(sfp, buf, count, srp);
 468                 goto free_old_hdr;
 469         }
 470
 471         hp = &srp->header;
 472         if (old_hdr == NULL) {
 473                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 474                 if (! old_hdr) {
 475                         retval = -ENOMEM;
 476                         goto free_old_hdr;
 477                 }
 478         }
 479         memset(old_hdr, 0, SZ_SG_HEADER);
 480         old_hdr->reply_len = (int) hp->timeout;
 481         old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
 482         old_hdr->pack_id = hp->pack_id;
 483         old_hdr->twelve_byte =
 484             ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
 485         old_hdr->target_status = hp->masked_status;
 486         old_hdr->host_status = hp->host_status;
 487         old_hdr->driver_status = hp->driver_status;
 488         if ((CHECK_CONDITION & hp->masked_status) ||
 489             (DRIVER_SENSE & hp->driver_status))
 490                 memcpy(old_hdr->sense_buffer, srp->sense_b,
 491                        sizeof (old_hdr->sense_buffer));
 492         switch (hp->host_status) {
 493         /* This setup of 'result' is for backward compatibility and is best
 494            ignored by the user who should use target, host + driver status */
 495         case DID_OK:
 496         case DID_PASSTHROUGH:
 497         case DID_SOFT_ERROR:
 498                 old_hdr->result = 0;
 499                 break;
 500         case DID_NO_CONNECT:
 501         case DID_BUS_BUSY:
 502         case DID_TIME_OUT:
 503                 old_hdr->result = EBUSY;
 504                 break;
 505         case DID_BAD_TARGET:
 506         case DID_ABORT:
 507         case DID_PARITY:
 508         case DID_RESET:
 509         case DID_BAD_INTR:
 510                 old_hdr->result = EIO;
 511                 break;
 512         case DID_ERROR:
 513                 old_hdr->result = (srp->sense_b[0] == 0 &&
 514                                   hp->masked_status == GOOD) ? 0 : EIO;
 515                 break;
 516         default:
 517                 old_hdr->result = EIO;
 518                 break;
 519         }
 520
 521         /* Now copy the result back to the user buffer.  */
 522         if (count >= SZ_SG_HEADER) {
 523                 if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
 524                         retval = -EFAULT;
 525                         goto free_old_hdr;
 526                 }
 527                 buf += SZ_SG_HEADER;
 528                 if (count > old_hdr->reply_len)
 529                         count = old_hdr->reply_len;
 530                 if (count > SZ_SG_HEADER) {
 531                         if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
 532                                 retval = -EFAULT;
 533                                 goto free_old_hdr;
 534                         }
 535                 }
 536         } else
 537                 count = (old_hdr->result == 0) ? 0 : -EIO;
 538         sg_finish_rem_req(srp);
 539         retval = count;
 540 free_old_hdr:
 541         kfree(old_hdr);
 542         return retval;
 543 }
 544
 545 static ssize_t
 546 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
 547 {
 548         sg_io_hdr_t *hp = &srp->header;
 549         int err = 0;
 550         int len;
 551
 552         if (count < SZ_SG_IO_HDR) {
 553                 err = -EINVAL;
 554                 goto err_out;
 555         }
 556         hp->sb_len_wr = 0;
 557         if ((hp->mx_sb_len > 0) && hp->sbp) {
 558                 if ((CHECK_CONDITION & hp->masked_status) ||
 559                     (DRIVER_SENSE & hp->driver_status)) {
 560                         int sb_len = SCSI_SENSE_BUFFERSIZE;
 561                         sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
 562                         len = 8 + (int) srp->sense_b[7];        /* Additional sense length field */
 563                         len = (len > sb_len) ? sb_len : len;
 564                         if (copy_to_user(hp->sbp, srp->sense_b, len)) {
 565                                 err = -EFAULT;
 566                                 goto err_out;
 567                         }
 568                         hp->sb_len_wr = len;
 569                 }
 570         }
 571         if (hp->masked_status || hp->host_status || hp->driver_status)
 572                 hp->info |= SG_INFO_CHECK;
 573         if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
 574                 err = -EFAULT;
 575                 goto err_out;
 576         }
 577 err_out:
 578         err = sg_finish_rem_req(srp);
 579         return (0 == err) ? count : err;
 580 }
 581
 582 static ssize_t
 583 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 584 {
 585         int mxsize, cmd_size, k;
 586         int input_size, blocking;
 587         unsigned char opcode;
 588         Sg_device *sdp;
 589         Sg_fd *sfp;
 590         Sg_request *srp;
 591         struct sg_header old_hdr;
 592         sg_io_hdr_t *hp;
 593         unsigned char cmnd[SG_MAX_CDB_SIZE];
 594
 595         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 596                 return -ENXIO;
 597         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 598                                       "sg_write: count=%d\n", (int) count));
 599         if (atomic_read(&sdp->detaching))
 600                 return -ENODEV;
 601         if (!((filp->f_flags & O_NONBLOCK) ||
 602               scsi_block_when_processing_errors(sdp->device)))
 603                 return -ENXIO;
 604
 605         if (!access_ok(VERIFY_READ, buf, count))
 606                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 607         if (count < SZ_SG_HEADER)
 608                 return -EIO;
 609         if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
 610                 return -EFAULT;
 611         blocking = !(filp->f_flags & O_NONBLOCK);
 612         if (old_hdr.reply_len < 0)
 613                 return sg_new_write(sfp, filp, buf, count,
 614                                     blocking, 0, 0, NULL);
 615         if (count < (SZ_SG_HEADER + 6))
 616                 return -EIO;    /* The minimum scsi command length is 6 bytes. */
 617
 618         if (!(srp = sg_add_request(sfp))) {
 619                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 620                                               "sg_write: queue full\n"));
 621                 return -EDOM;
 622         }
 623         buf += SZ_SG_HEADER;
 624         __get_user(opcode, buf);
 625         if (sfp->next_cmd_len > 0) {
 626                 cmd_size = sfp->next_cmd_len;
 627                 sfp->next_cmd_len = 0;  /* reset so only this write() effected */
 628         } else {
 629                 cmd_size = COMMAND_SIZE(opcode);        /* based on SCSI command group */
 630                 if ((opcode >= 0xc0) && old_hdr.twelve_byte)
 631                         cmd_size = 12;
 632         }
 633         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
 634                 "sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
 635 /* Determine buffer size.  */
 636         input_size = count - cmd_size;
 637         mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
 638         mxsize -= SZ_SG_HEADER;
 639         input_size -= SZ_SG_HEADER;
 640         if (input_size < 0) {
 641                 sg_remove_request(sfp, srp);
 642                 return -EIO;    /* User did not pass enough bytes for this command. */
 643         }
 644         hp = &srp->header;
 645         hp->interface_id = '\0';        /* indicator of old interface tunnelled */
 646         hp->cmd_len = (unsigned char) cmd_size;
 647         hp->iovec_count = 0;
 648         hp->mx_sb_len = 0;
 649         if (input_size > 0)
 650                 hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
 651                     SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
 652         else
 653                 hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
 654         hp->dxfer_len = mxsize;
 655         if (hp->dxfer_direction == SG_DXFER_TO_DEV)
 656                 hp->dxferp = (char __user *)buf + cmd_size;
 657         else
 658                 hp->dxferp = NULL;
 659         hp->sbp = NULL;
 660         hp->timeout = old_hdr.reply_len;        /* structure abuse ... */
 661         hp->flags = input_size; /* structure abuse ... */
 662         hp->pack_id = old_hdr.pack_id;
 663         hp->usr_ptr = NULL;
 664         if (__copy_from_user(cmnd, buf, cmd_size))
 665                 return -EFAULT;
 666         /*
 667          * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
 668          * but is is possible that the app intended SG_DXFER_TO_DEV, because there
 669          * is a non-zero input_size, so emit a warning.
 670          */
 671         if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
 672                 static char cmd[TASK_COMM_LEN];
 673                 if (strcmp(current->comm, cmd)) {
 674                         printk_ratelimited(KERN_WARNING
 675                                            "sg_write: data in/out %d/%d bytes "
 676                                            "for SCSI command 0x%x-- guessing "
 677                                            "data in;\n   program %s not setting "
 678                                            "count and/or reply_len properly\n",
 679                                            old_hdr.reply_len - (int)SZ_SG_HEADER,
 680                                            input_size, (unsigned int) cmnd[0],
 681                                            current->comm);
 682                         strcpy(cmd, current->comm);
 683                 }
 684         }
 685         k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
 686         return (k < 0) ? k : count;
 687 }
 688
 689 static ssize_t
 690 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 691                  size_t count, int blocking, int read_only, int sg_io_owned,
 692                  Sg_request **o_srp)
 693 {
 694         int k;
 695         Sg_request *srp;
 696         sg_io_hdr_t *hp;
 697         unsigned char cmnd[SG_MAX_CDB_SIZE];
 698         int timeout;
 699         unsigned long ul_timeout;
 700
 701         if (count < SZ_SG_IO_HDR)
 702                 return -EINVAL;
 703         if (!access_ok(VERIFY_READ, buf, count))
 704                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 705
 706         sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
 707         if (!(srp = sg_add_request(sfp))) {
 708                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 709                                               "sg_new_write: queue full\n"));
 710                 return -EDOM;
 711         }
 712         srp->sg_io_owned = sg_io_owned;
 713         hp = &srp->header;
 714         if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
 715                 sg_remove_request(sfp, srp);
 716                 return -EFAULT;
 717         }
 718         if (hp->interface_id != 'S') {
 719                 sg_remove_request(sfp, srp);
 720                 return -ENOSYS;
 721         }
 722         if (hp->flags & SG_FLAG_MMAP_IO) {
 723                 if (hp->dxfer_len > sfp->reserve.bufflen) {
 724                         sg_remove_request(sfp, srp);
 725                         return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
 726                 }
 727                 if (hp->flags & SG_FLAG_DIRECT_IO) {
 728                         sg_remove_request(sfp, srp);
 729                         return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
 730                 }
 731                 if (sg_res_in_use(sfp)) {
 732                         sg_remove_request(sfp, srp);
 733                         return -EBUSY;  /* reserve buffer already being used */
 734                 }
 735         }
 736         ul_timeout = msecs_to_jiffies(srp->header.timeout);
 737         timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
 738         if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
 739                 sg_remove_request(sfp, srp);
 740                 return -EMSGSIZE;
 741         }
 742         if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
 743                 sg_remove_request(sfp, srp);
 744                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 745         }
 746         if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 747                 sg_remove_request(sfp, srp);
 748                 return -EFAULT;
 749         }
 750         if (read_only && sg_allow_access(file, cmnd)) {
 751                 sg_remove_request(sfp, srp);
 752                 return -EPERM;
 753         }
 754         k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
 755         if (k < 0)
 756                 return k;
 757         if (o_srp)
 758                 *o_srp = srp;
 759         return count;
 760 }
 761
 762 static int
 763 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 764                 unsigned char *cmnd, int timeout, int blocking)
 765 {
 766         int k, data_dir, at_head;
 767         Sg_device *sdp = sfp->parentdp;
 768         sg_io_hdr_t *hp = &srp->header;
 769
 770         srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
 771         hp->status = 0;
 772         hp->masked_status = 0;
 773         hp->msg_status = 0;
 774         hp->info = 0;
 775         hp->host_status = 0;
 776         hp->driver_status = 0;
 777         hp->resid = 0;
 778         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
 779                         "sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
 780                         (int) cmnd[0], (int) hp->cmd_len));
 781
 782         k = sg_start_req(srp, cmnd);
 783         if (k) {
 784                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 785                         "sg_common_write: start_req err=%d\n", k));
 786                 sg_finish_rem_req(srp);
 787                 return k;       /* probably out of space --> ENOMEM */
 788         }
 789         if (atomic_read(&sdp->detaching)) {
 790                 if (srp->bio)
 791                         blk_end_request_all(srp->rq, -EIO);
 792                 sg_finish_rem_req(srp);
 793                 return -ENODEV;
 794         }
 795
 796         switch (hp->dxfer_direction) {
 797         case SG_DXFER_TO_FROM_DEV:
 798         case SG_DXFER_FROM_DEV:
 799                 data_dir = DMA_FROM_DEVICE;
 800                 break;
 801         case SG_DXFER_TO_DEV:
 802                 data_dir = DMA_TO_DEVICE;
 803                 break;
 804         case SG_DXFER_UNKNOWN:
 805                 data_dir = DMA_BIDIRECTIONAL;
 806                 break;
 807         default:
 808                 data_dir = DMA_NONE;
 809                 break;
 810         }
 811         hp->duration = jiffies_to_msecs(jiffies);
 812         if (hp->interface_id != '\0' && /* v3 (or later) interface */
 813             (SG_FLAG_Q_AT_TAIL & hp->flags))
 814                 at_head = 0;
 815         else
 816                 at_head = 1;
 817
 818         srp->rq->timeout = timeout;
 819         kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
 820         blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
 821                               srp->rq, at_head, sg_rq_end_io);
 822         return 0;
 823 }
 824
 825 static int srp_done(Sg_fd *sfp, Sg_request *srp)
 826 {
 827         unsigned long flags;
 828         int ret;
 829
 830         read_lock_irqsave(&sfp->rq_list_lock, flags);
 831         ret = srp->done;
 832         read_unlock_irqrestore(&sfp->rq_list_lock, flags);
 833         return ret;
 834 }
 835
 836 static int max_sectors_bytes(struct request_queue *q)
 837 {
 838         unsigned int max_sectors = queue_max_sectors(q);
 839
 840         max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
 841
 842         return max_sectors << 9;
 843 }
 844
 845 static long
 846 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
 847 {
 848         void __user *p = (void __user *)arg;
 849         int __user *ip = p;
 850         int result, val, read_only;
 851         Sg_device *sdp;
 852         Sg_fd *sfp;
 853         Sg_request *srp;
 854         unsigned long iflags;
 855
 856         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 857                 return -ENXIO;
 858
 859         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 860                                    "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
 861         read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
 862
 863         switch (cmd_in) {
 864         case SG_IO:
 865                 if (atomic_read(&sdp->detaching))
 866                         return -ENODEV;
 867                 if (!scsi_block_when_processing_errors(sdp->device))
 868                         return -ENXIO;
 869                 if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
 870                         return -EFAULT;
 871                 result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 872                                  1, read_only, 1, &srp);
 873                 if (result < 0)
 874                         return result;
 875                 result = wait_event_interruptible(sfp->read_wait,
 876                         (srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
 877                 if (atomic_read(&sdp->detaching))
 878                         return -ENODEV;
 879                 write_lock_irq(&sfp->rq_list_lock);
 880                 if (srp->done) {
 881                         srp->done = 2;
 882                         write_unlock_irq(&sfp->rq_list_lock);
 883                         result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
 884                         return (result < 0) ? result : 0;
 885                 }
 886                 srp->orphan = 1;
 887                 write_unlock_irq(&sfp->rq_list_lock);
 888                 return result;  /* -ERESTARTSYS because signal hit process */
 889         case SG_SET_TIMEOUT:
 890                 result = get_user(val, ip);
 891                 if (result)
 892                         return result;
 893                 if (val < 0)
 894                         return -EIO;
 895                 if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
 896                     val = MULDIV (INT_MAX, USER_HZ, HZ);
 897                 sfp->timeout_user = val;
 898                 sfp->timeout = MULDIV (val, HZ, USER_HZ);
 899
 900                 return 0;
 901         case SG_GET_TIMEOUT:    /* N.B. User receives timeout as return value */
 902                                 /* strange ..., for backward compatibility */
 903                 return sfp->timeout_user;
 904         case SG_SET_FORCE_LOW_DMA:
 905                 result = get_user(val, ip);
 906                 if (result)
 907                         return result;
 908                 if (val) {
 909                         sfp->low_dma = 1;
 910                         if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
 911                                 val = (int) sfp->reserve.bufflen;
 912                                 sg_remove_scat(sfp, &sfp->reserve);
 913                                 sg_build_reserve(sfp, val);
 914                         }
 915                 } else {
 916                         if (atomic_read(&sdp->detaching))
 917                                 return -ENODEV;
 918                         sfp->low_dma = sdp->device->host->unchecked_isa_dma;
 919                 }
 920                 return 0;
 921         case SG_GET_LOW_DMA:
 922                 return put_user((int) sfp->low_dma, ip);
 923         case SG_GET_SCSI_ID:
 924                 if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
 925                         return -EFAULT;
 926                 else {
 927                         sg_scsi_id_t __user *sg_idp = p;
 928
 929                         if (atomic_read(&sdp->detaching))
 930                                 return -ENODEV;
 931                         __put_user((int) sdp->device->host->host_no,
 932                                    &sg_idp->host_no);
 933                         __put_user((int) sdp->device->channel,
 934                                    &sg_idp->channel);
 935                         __put_user((int) sdp->device->id, &sg_idp->scsi_id);
 936                         __put_user((int) sdp->device->lun, &sg_idp->lun);
 937                         __put_user((int) sdp->device->type, &sg_idp->scsi_type);
 938                         __put_user((short) sdp->device->host->cmd_per_lun,
 939                                    &sg_idp->h_cmd_per_lun);
 940                         __put_user((short) sdp->device->queue_depth,
 941                                    &sg_idp->d_queue_depth);
 942                         __put_user(0, &sg_idp->unused[0]);
 943                         __put_user(0, &sg_idp->unused[1]);
 944                         return 0;
 945                 }
 946         case SG_SET_FORCE_PACK_ID:
 947                 result = get_user(val, ip);
 948                 if (result)
 949                         return result;
 950                 sfp->force_packid = val ? 1 : 0;
 951                 return 0;
 952         case SG_GET_PACK_ID:
 953                 if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
 954                         return -EFAULT;
 955                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
 956                 for (srp = sfp->headrp; srp; srp = srp->nextrp) {
 957                         if ((1 == srp->done) && (!srp->sg_io_owned)) {
 958                                 read_unlock_irqrestore(&sfp->rq_list_lock,
 959                                                        iflags);
 960                                 __put_user(srp->header.pack_id, ip);
 961                                 return 0;
 962                         }
 963                 }
 964                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
 965                 __put_user(-1, ip);
 966                 return 0;
 967         case SG_GET_NUM_WAITING:
 968                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
 969                 for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
 970                         if ((1 == srp->done) && (!srp->sg_io_owned))
 971                                 ++val;
 972                 }
 973                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
 974                 return put_user(val, ip);
 975         case SG_GET_SG_TABLESIZE:
 976                 return put_user(sdp->sg_tablesize, ip);
 977         case SG_SET_RESERVED_SIZE:
 978                 result = get_user(val, ip);
 979                 if (result)
 980                         return result;
 981                 if (val < 0)
 982                         return -EINVAL;
 983                 val = min_t(int, val,
 984                             max_sectors_bytes(sdp->device->request_queue));
 985                 if (val != sfp->reserve.bufflen) {
 986                         if (sg_res_in_use(sfp) || sfp->mmap_called)
 987                                 return -EBUSY;
 988                         sg_remove_scat(sfp, &sfp->reserve);
 989                         sg_build_reserve(sfp, val);
 990                 }
 991                 return 0;
 992         case SG_GET_RESERVED_SIZE:
 993                 val = min_t(int, sfp->reserve.bufflen,
 994                             max_sectors_bytes(sdp->device->request_queue));
 995                 return put_user(val, ip);
 996         case SG_SET_COMMAND_Q:
 997                 result = get_user(val, ip);
 998                 if (result)
 999                         return result;
1000                 sfp->cmd_q = val ? 1 : 0;
1001                 return 0;
1002         case SG_GET_COMMAND_Q:
1003                 return put_user((int) sfp->cmd_q, ip);
1004         case SG_SET_KEEP_ORPHAN:
1005                 result = get_user(val, ip);
1006                 if (result)
1007                         return result;
1008                 sfp->keep_orphan = val;
1009                 return 0;
1010         case SG_GET_KEEP_ORPHAN:
1011                 return put_user((int) sfp->keep_orphan, ip);
1012         case SG_NEXT_CMD_LEN:
1013                 result = get_user(val, ip);
1014                 if (result)
1015                         return result;
1016                 sfp->next_cmd_len = (val > 0) ? val : 0;
1017                 return 0;
1018         case SG_GET_VERSION_NUM:
1019                 return put_user(sg_version_num, ip);
1020         case SG_GET_ACCESS_COUNT:
1021                 /* faked - we don't have a real access count anymore */
1022                 val = (sdp->device ? 1 : 0);
1023                 return put_user(val, ip);
1024         case SG_GET_REQUEST_TABLE:
1025                 if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
1026                         return -EFAULT;
1027                 else {
1028                         sg_req_info_t *rinfo;
1029                         unsigned int ms;
1030
1031                         rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
1032                                                                 GFP_KERNEL);
1033                         if (!rinfo)
1034                                 return -ENOMEM;
1035                         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1036                         for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
1037                              ++val, srp = srp ? srp->nextrp : srp) {
1038                                 memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
1039                                 if (srp) {
1040                                         rinfo[val].req_state = srp->done + 1;
1041                                         rinfo[val].problem =
1042                                             srp->header.masked_status &
1043                                             srp->header.host_status &
1044                                             srp->header.driver_status;
1045                                         if (srp->done)
1046                                                 rinfo[val].duration =
1047                                                         srp->header.duration;
1048                                         else {
1049                                                 ms = jiffies_to_msecs(jiffies);
1050                                                 rinfo[val].duration =
1051                                                     (ms > srp->header.duration) ?
1052                                                     (ms - srp->header.duration) : 0;
1053                                         }
1054                                         rinfo[val].orphan = srp->orphan;
1055                                         rinfo[val].sg_io_owned =
1056                                                         srp->sg_io_owned;
1057                                         rinfo[val].pack_id =
1058                                                         srp->header.pack_id;
1059                                         rinfo[val].usr_ptr =
1060                                                         srp->header.usr_ptr;
1061                                 }
1062                         }
1063                         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1064                         result = __copy_to_user(p, rinfo,
1065                                                 SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1066                         result = result ? -EFAULT : 0;
1067                         kfree(rinfo);
1068                         return result;
1069                 }
1070         case SG_EMULATED_HOST:
1071                 if (atomic_read(&sdp->detaching))
1072                         return -ENODEV;
1073                 return put_user(sdp->device->host->hostt->emulated, ip);
1074         case SG_SCSI_RESET:
1075                 if (atomic_read(&sdp->detaching))
1076                         return -ENODEV;
1077                 if (filp->f_flags & O_NONBLOCK) {
1078                         if (scsi_host_in_recovery(sdp->device->host))
1079                                 return -EBUSY;
1080                 } else if (!scsi_block_when_processing_errors(sdp->device))
1081                         return -EBUSY;
1082                 result = get_user(val, ip);
1083                 if (result)
1084                         return result;
1085                 if (SG_SCSI_RESET_NOTHING == val)
1086                         return 0;
1087                 switch (val) {
1088                 case SG_SCSI_RESET_DEVICE:
1089                         val = SCSI_TRY_RESET_DEVICE;
1090                         break;
1091                 case SG_SCSI_RESET_TARGET:
1092                         val = SCSI_TRY_RESET_TARGET;
1093                         break;
1094                 case SG_SCSI_RESET_BUS:
1095                         val = SCSI_TRY_RESET_BUS;
1096                         break;
1097                 case SG_SCSI_RESET_HOST:
1098                         val = SCSI_TRY_RESET_HOST;
1099                         break;
1100                 default:
1101                         return -EINVAL;
1102                 }
1103                 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1104                         return -EACCES;
1105                 return (scsi_reset_provider(sdp->device, val) ==
1106                         SUCCESS) ? 0 : -EIO;
1107         case SCSI_IOCTL_SEND_COMMAND:
1108                 if (atomic_read(&sdp->detaching))
1109                         return -ENODEV;
1110                 if (read_only) {
1111                         unsigned char opcode = WRITE_6;
1112                         Scsi_Ioctl_Command __user *siocp = p;
1113
1114                         if (copy_from_user(&opcode, siocp->data, 1))
1115                                 return -EFAULT;
1116                         if (sg_allow_access(filp, &opcode))
1117                                 return -EPERM;
1118                 }
1119                 return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1120         case SG_SET_DEBUG:
1121                 result = get_user(val, ip);
1122                 if (result)
1123                         return result;
1124                 sdp->sgdebug = (char) val;
1125                 return 0;
1126         case SCSI_IOCTL_GET_IDLUN:
1127         case SCSI_IOCTL_GET_BUS_NUMBER:
1128         case SCSI_IOCTL_PROBE_HOST:
1129         case SG_GET_TRANSFORM:
1130                 if (atomic_read(&sdp->detaching))
1131                         return -ENODEV;
1132                 return scsi_ioctl(sdp->device, cmd_in, p);
1133         case BLKSECTGET:
1134                 return put_user(max_sectors_bytes(sdp->device->request_queue),
1135                                 ip);
1136         case BLKTRACESETUP:
1137                 return blk_trace_setup(sdp->device->request_queue,
1138                                        sdp->disk->disk_name,
1139                                        MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1140                                        NULL,
1141                                        (char *)arg);
1142         case BLKTRACESTART:
1143                 return blk_trace_startstop(sdp->device->request_queue, 1);
1144         case BLKTRACESTOP:
1145                 return blk_trace_startstop(sdp->device->request_queue, 0);
1146         case BLKTRACETEARDOWN:
1147                 return blk_trace_remove(sdp->device->request_queue);
1148         default:
1149                 if (read_only)
1150                         return -EPERM;  /* don't know so take safe approach */
1151                 return scsi_ioctl(sdp->device, cmd_in, p);
1152         }
1153 }
1154
1155 #ifdef CONFIG_COMPAT
1156 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1157 {
1158         Sg_device *sdp;
1159         Sg_fd *sfp;
1160         struct scsi_device *sdev;
1161
1162         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1163                 return -ENXIO;
1164
1165         sdev = sdp->device;
1166         if (sdev->host->hostt->compat_ioctl) {
1167                 int ret;
1168
1169                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1170
1171                 return ret;
1172         }
1173
1174         return -ENOIOCTLCMD;
1175 }
1176 #endif
1177
1178 static unsigned int
1179 sg_poll(struct file *filp, poll_table * wait)
1180 {
1181         unsigned int res = 0;
1182         Sg_device *sdp;
1183         Sg_fd *sfp;
1184         Sg_request *srp;
1185         int count = 0;
1186         unsigned long iflags;
1187
1188         sfp = filp->private_data;
1189         if (!sfp)
1190                 return POLLERR;
1191         sdp = sfp->parentdp;
1192         if (!sdp)
1193                 return POLLERR;
1194         poll_wait(filp, &sfp->read_wait, wait);
1195         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1196         for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1197                 /* if any read waiting, flag it */
1198                 if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1199                         res = POLLIN | POLLRDNORM;
1200                 ++count;
1201         }
1202         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1203
1204         if (atomic_read(&sdp->detaching))
1205                 res |= POLLHUP;
1206         else if (!sfp->cmd_q) {
1207                 if (0 == count)
1208                         res |= POLLOUT | POLLWRNORM;
1209         } else if (count < SG_MAX_QUEUE)
1210                 res |= POLLOUT | POLLWRNORM;
1211         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1212                                       "sg_poll: res=0x%x\n", (int) res));
1213         return res;
1214 }
1215
1216 static int
1217 sg_fasync(int fd, struct file *filp, int mode)
1218 {
1219         Sg_device *sdp;
1220         Sg_fd *sfp;
1221
1222         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1223                 return -ENXIO;
1224         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1225                                       "sg_fasync: mode=%d\n", mode));
1226
1227         return fasync_helper(fd, filp, mode, &sfp->async_qp);
1228 }
1229
1230 static int
1231 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1232 {
1233         Sg_fd *sfp;
1234         unsigned long offset, len, sa;
1235         Sg_scatter_hold *rsv_schp;
1236         int k, length;
1237
1238         if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1239                 return VM_FAULT_SIGBUS;
1240         rsv_schp = &sfp->reserve;
1241         offset = vmf->pgoff << PAGE_SHIFT;
1242         if (offset >= rsv_schp->bufflen)
1243                 return VM_FAULT_SIGBUS;
1244         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1245                                       "sg_vma_fault: offset=%lu, scatg=%d\n",
1246                                       offset, rsv_schp->k_use_sg));
1247         sa = vma->vm_start;
1248         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1249         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1250                 len = vma->vm_end - sa;
1251                 len = (len < length) ? len : length;
1252                 if (offset < len) {
1253                         struct page *page = nth_page(rsv_schp->pages[k],
1254                                                      offset >> PAGE_SHIFT);
1255                         get_page(page); /* increment page count */
1256                         vmf->page = page;
1257                         return 0; /* success */
1258                 }
1259                 sa += len;
1260                 offset -= len;
1261         }
1262
1263         return VM_FAULT_SIGBUS;
1264 }
1265
1266 static const struct vm_operations_struct sg_mmap_vm_ops = {
1267         .fault = sg_vma_fault,
1268 };
1269
1270 static int
1271 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1272 {
1273         Sg_fd *sfp;
1274         unsigned long req_sz, len, sa;
1275         Sg_scatter_hold *rsv_schp;
1276         int k, length;
1277
1278         if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1279                 return -ENXIO;
1280         req_sz = vma->vm_end - vma->vm_start;
1281         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1282                                       "sg_mmap starting, vm_start=%p, len=%d\n",
1283                                       (void *) vma->vm_start, (int) req_sz));
1284         if (vma->vm_pgoff)
1285                 return -EINVAL; /* want no offset */
1286         rsv_schp = &sfp->reserve;
1287         if (req_sz > rsv_schp->bufflen)
1288                 return -ENOMEM; /* cannot map more than reserved buffer */
1289
1290         sa = vma->vm_start;
1291         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1292         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1293                 len = vma->vm_end - sa;
1294                 len = (len < length) ? len : length;
1295                 sa += len;
1296         }
1297
1298         sfp->mmap_called = 1;
1299         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1300         vma->vm_private_data = sfp;
1301         vma->vm_ops = &sg_mmap_vm_ops;
1302         return 0;
1303 }
1304
1305 static void
1306 sg_rq_end_io_usercontext(struct work_struct *work)
1307 {
1308         struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1309         struct sg_fd *sfp = srp->parentfp;
1310
1311         sg_finish_rem_req(srp);
1312         kref_put(&sfp->f_ref, sg_remove_sfp);
1313 }
1314
1315 /*
1316  * This function is a "bottom half" handler that is called by the mid
1317  * level when a command is completed (or has failed).
1318  */
1319 static void
1320 sg_rq_end_io(struct request *rq, int uptodate)
1321 {
1322         struct sg_request *srp = rq->end_io_data;
1323         Sg_device *sdp;
1324         Sg_fd *sfp;
1325         unsigned long iflags;
1326         unsigned int ms;
1327         char *sense;
1328         int result, resid, done = 1;
1329
1330         if (WARN_ON(srp->done != 0))
1331                 return;
1332
1333         sfp = srp->parentfp;
1334         if (WARN_ON(sfp == NULL))
1335                 return;
1336
1337         sdp = sfp->parentdp;
1338         if (unlikely(atomic_read(&sdp->detaching)))
1339                 pr_info("%s: device detaching\n", __func__);
1340
1341         sense = rq->sense;
1342         result = rq->errors;
1343         resid = rq->resid_len;
1344
1345         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1346                                       "sg_cmd_done: pack_id=%d, res=0x%x\n",
1347                                       srp->header.pack_id, result));
1348         srp->header.resid = resid;
1349         ms = jiffies_to_msecs(jiffies);
1350         srp->header.duration = (ms > srp->header.duration) ?
1351                                 (ms - srp->header.duration) : 0;
1352         if (0 != result) {
1353                 struct scsi_sense_hdr sshdr;
1354
1355                 srp->header.status = 0xff & result;
1356                 srp->header.masked_status = status_byte(result);
1357                 srp->header.msg_status = msg_byte(result);
1358                 srp->header.host_status = host_byte(result);
1359                 srp->header.driver_status = driver_byte(result);
1360                 if ((sdp->sgdebug > 0) &&
1361                     ((CHECK_CONDITION == srp->header.masked_status) ||
1362                      (COMMAND_TERMINATED == srp->header.masked_status)))
1363                         __scsi_print_sense(__func__, sense,
1364                                            SCSI_SENSE_BUFFERSIZE);
1365
1366                 /* Following if statement is a patch supplied by Eric Youngdale */
1367                 if (driver_byte(result) != 0
1368                     && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1369                     && !scsi_sense_is_deferred(&sshdr)
1370                     && sshdr.sense_key == UNIT_ATTENTION
1371                     && sdp->device->removable) {
1372                         /* Detected possible disc change. Set the bit - this */
1373                         /* may be used if there are filesystems using this device */
1374                         sdp->device->changed = 1;
1375                 }
1376         }
1377         /* Rely on write phase to clean out srp status values, so no "else" */
1378
1379         write_lock_irqsave(&sfp->rq_list_lock, iflags);
1380         if (unlikely(srp->orphan)) {
1381                 if (sfp->keep_orphan)
1382                         srp->sg_io_owned = 0;
1383                 else
1384                         done = 0;
1385         }
1386         srp->done = done;
1387         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1388
1389         if (likely(done)) {
1390                 /* Now wake up any sg_read() that is waiting for this
1391                  * packet.
1392                  */
1393                 wake_up_interruptible(&sfp->read_wait);
1394                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1395                 kref_put(&sfp->f_ref, sg_remove_sfp);
1396         } else {
1397                 INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1398                 schedule_work(&srp->ew.work);
1399         }
1400 }
1401
1402 static const struct file_operations sg_fops = {
1403         .owner = THIS_MODULE,
1404         .read = sg_read,
1405         .write = sg_write,
1406         .poll = sg_poll,
1407         .unlocked_ioctl = sg_ioctl,
1408 #ifdef CONFIG_COMPAT
1409         .compat_ioctl = sg_compat_ioctl,
1410 #endif
1411         .open = sg_open,
1412         .mmap = sg_mmap,
1413         .release = sg_release,
1414         .fasync = sg_fasync,
1415         .llseek = no_llseek,
1416 };
1417
1418 static struct class *sg_sysfs_class;
1419
1420 static int sg_sysfs_valid = 0;
1421
1422 static Sg_device *
1423 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1424 {
1425         struct request_queue *q = scsidp->request_queue;
1426         Sg_device *sdp;
1427         unsigned long iflags;
1428         int error;
1429         u32 k;
1430
1431         sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1432         if (!sdp) {
1433                 sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1434                             "failure\n", __func__);
1435                 return ERR_PTR(-ENOMEM);
1436         }
1437
1438         idr_preload(GFP_KERNEL);
1439         write_lock_irqsave(&sg_index_lock, iflags);
1440
1441         error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1442         if (error < 0) {
1443                 if (error == -ENOSPC) {
1444                         sdev_printk(KERN_WARNING, scsidp,
1445                                     "Unable to attach sg device type=%d, minor number exceeds %d\n",
1446                                     scsidp->type, SG_MAX_DEVS - 1);
1447                         error = -ENODEV;
1448                 } else {
1449                         sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1450                                     "allocation Sg_device failure: %d\n",
1451                                     __func__, error);
1452                 }
1453                 goto out_unlock;
1454         }
1455         k = error;
1456
1457         SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1458                                         "sg_alloc: dev=%d \n", k));
1459         sprintf(disk->disk_name, "sg%d", k);
1460         disk->first_minor = k;
1461         sdp->disk = disk;
1462         sdp->device = scsidp;
1463         mutex_init(&sdp->open_rel_lock);
1464         INIT_LIST_HEAD(&sdp->sfds);
1465         init_waitqueue_head(&sdp->open_wait);
1466         atomic_set(&sdp->detaching, 0);
1467         rwlock_init(&sdp->sfd_lock);
1468         sdp->sg_tablesize = queue_max_segments(q);
1469         sdp->index = k;
1470         kref_init(&sdp->d_ref);
1471         error = 0;
1472
1473 out_unlock:
1474         write_unlock_irqrestore(&sg_index_lock, iflags);
1475         idr_preload_end();
1476
1477         if (error) {
1478                 kfree(sdp);
1479                 return ERR_PTR(error);
1480         }
1481         return sdp;
1482 }
1483
1484 static int
1485 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1486 {
1487         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1488         struct gendisk *disk;
1489         Sg_device *sdp = NULL;
1490         struct cdev * cdev = NULL;
1491         int error;
1492         unsigned long iflags;
1493
1494         disk = alloc_disk(1);
1495         if (!disk) {
1496                 pr_warn("%s: alloc_disk failed\n", __func__);
1497                 return -ENOMEM;
1498         }
1499         disk->major = SCSI_GENERIC_MAJOR;
1500
1501         error = -ENOMEM;
1502         cdev = cdev_alloc();
1503         if (!cdev) {
1504                 pr_warn("%s: cdev_alloc failed\n", __func__);
1505                 goto out;
1506         }
1507         cdev->owner = THIS_MODULE;
1508         cdev->ops = &sg_fops;
1509
1510         sdp = sg_alloc(disk, scsidp);
1511         if (IS_ERR(sdp)) {
1512                 pr_warn("%s: sg_alloc failed\n", __func__);
1513                 error = PTR_ERR(sdp);
1514                 goto out;
1515         }
1516
1517         error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1518         if (error)
1519                 goto cdev_add_err;
1520
1521         sdp->cdev = cdev;
1522         if (sg_sysfs_valid) {
1523                 struct device *sg_class_member;
1524
1525                 sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1526                                                 MKDEV(SCSI_GENERIC_MAJOR,
1527                                                       sdp->index),
1528                                                 sdp, "%s", disk->disk_name);
1529                 if (IS_ERR(sg_class_member)) {
1530                         pr_err("%s: device_create failed\n", __func__);
1531                         error = PTR_ERR(sg_class_member);
1532                         goto cdev_add_err;
1533                 }
1534                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1535                                           &sg_class_member->kobj, "generic");
1536                 if (error)
1537                         pr_err("%s: unable to make symlink 'generic' back "
1538                                "to sg%d\n", __func__, sdp->index);
1539         } else
1540                 pr_warn("%s: sg_sys Invalid\n", __func__);
1541
1542         sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1543                     "type %d\n", sdp->index, scsidp->type);
1544
1545         dev_set_drvdata(cl_dev, sdp);
1546
1547         return 0;
1548
1549 cdev_add_err:
1550         write_lock_irqsave(&sg_index_lock, iflags);
1551         idr_remove(&sg_index_idr, sdp->index);
1552         write_unlock_irqrestore(&sg_index_lock, iflags);
1553         kfree(sdp);
1554
1555 out:
1556         put_disk(disk);
1557         if (cdev)
1558                 cdev_del(cdev);
1559         return error;
1560 }
1561
1562 static void
1563 sg_device_destroy(struct kref *kref)
1564 {
1565         struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1566         unsigned long flags;
1567
1568         /* CAUTION!  Note that the device can still be found via idr_find()
1569          * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1570          * any other cleanup.
1571          */
1572
1573         write_lock_irqsave(&sg_index_lock, flags);
1574         idr_remove(&sg_index_idr, sdp->index);
1575         write_unlock_irqrestore(&sg_index_lock, flags);
1576
1577         SCSI_LOG_TIMEOUT(3,
1578                 sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1579
1580         put_disk(sdp->disk);
1581         kfree(sdp);
1582 }
1583
1584 static void
1585 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1586 {
1587         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1588         Sg_device *sdp = dev_get_drvdata(cl_dev);
1589         unsigned long iflags;
1590         Sg_fd *sfp;
1591         int val;
1592
1593         if (!sdp)
1594                 return;
1595         /* want sdp->detaching non-zero as soon as possible */
1596         val = atomic_inc_return(&sdp->detaching);
1597         if (val > 1)
1598                 return; /* only want to do following once per device */
1599
1600         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1601                                       "%s\n", __func__));
1602
1603         read_lock_irqsave(&sdp->sfd_lock, iflags);
1604         list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1605                 wake_up_interruptible_all(&sfp->read_wait);
1606                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1607         }
1608         wake_up_interruptible_all(&sdp->open_wait);
1609         read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1610
1611         sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1612         device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1613         cdev_del(sdp->cdev);
1614         sdp->cdev = NULL;
1615
1616         kref_put(&sdp->d_ref, sg_device_destroy);
1617 }
1618
1619 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1620 module_param_named(def_reserved_size, def_reserved_size, int,
1621                    S_IRUGO | S_IWUSR);
1622 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1623
1624 MODULE_AUTHOR("Douglas Gilbert");
1625 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1626 MODULE_LICENSE("GPL");
1627 MODULE_VERSION(SG_VERSION_STR);
1628 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1629
1630 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1631                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1632 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1633 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1634
1635 static int __init
1636 init_sg(void)
1637 {
1638         int rc;
1639
1640         if (scatter_elem_sz < PAGE_SIZE) {
1641                 scatter_elem_sz = PAGE_SIZE;
1642                 scatter_elem_sz_prev = scatter_elem_sz;
1643         }
1644         if (def_reserved_size >= 0)
1645                 sg_big_buff = def_reserved_size;
1646         else
1647                 def_reserved_size = sg_big_buff;
1648
1649         rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1650                                     SG_MAX_DEVS, "sg");
1651         if (rc)
1652                 return rc;
1653         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1654         if ( IS_ERR(sg_sysfs_class) ) {
1655                 rc = PTR_ERR(sg_sysfs_class);
1656                 goto err_out;
1657         }
1658         sg_sysfs_valid = 1;
1659         rc = scsi_register_interface(&sg_interface);
1660         if (0 == rc) {
1661 #ifdef CONFIG_SCSI_PROC_FS
1662                 sg_proc_init();
1663 #endif                          /* CONFIG_SCSI_PROC_FS */
1664                 return 0;
1665         }
1666         class_destroy(sg_sysfs_class);
1667 err_out:
1668         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1669         return rc;
1670 }
1671
1672 static void __exit
1673 exit_sg(void)
1674 {
1675 #ifdef CONFIG_SCSI_PROC_FS
1676         sg_proc_cleanup();
1677 #endif                          /* CONFIG_SCSI_PROC_FS */
1678         scsi_unregister_interface(&sg_interface);
1679         class_destroy(sg_sysfs_class);
1680         sg_sysfs_valid = 0;
1681         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1682                                  SG_MAX_DEVS);
1683         idr_destroy(&sg_index_idr);
1684 }
1685
1686 static int
1687 sg_start_req(Sg_request *srp, unsigned char *cmd)
1688 {
1689         int res;
1690         struct request *rq;
1691         Sg_fd *sfp = srp->parentfp;
1692         sg_io_hdr_t *hp = &srp->header;
1693         int dxfer_len = (int) hp->dxfer_len;
1694         int dxfer_dir = hp->dxfer_direction;
1695         unsigned int iov_count = hp->iovec_count;
1696         Sg_scatter_hold *req_schp = &srp->data;
1697         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1698         struct request_queue *q = sfp->parentdp->device->request_queue;
1699         struct rq_map_data *md, map_data;
1700         int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1701         unsigned char *long_cmdp = NULL;
1702
1703         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1704                                       "sg_start_req: dxfer_len=%d\n",
1705                                       dxfer_len));
1706
1707         if (hp->cmd_len > BLK_MAX_CDB) {
1708                 long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1709                 if (!long_cmdp)
1710                         return -ENOMEM;
1711         }
1712
1713         rq = blk_get_request(q, rw, GFP_ATOMIC);
1714         if (IS_ERR(rq)) {
1715                 kfree(long_cmdp);
1716                 return PTR_ERR(rq);
1717         }
1718
1719         blk_rq_set_block_pc(rq);
1720
1721         if (hp->cmd_len > BLK_MAX_CDB)
1722                 rq->cmd = long_cmdp;
1723         memcpy(rq->cmd, cmd, hp->cmd_len);
1724         rq->cmd_len = hp->cmd_len;
1725
1726         srp->rq = rq;
1727         rq->end_io_data = srp;
1728         rq->sense = srp->sense_b;
1729         rq->retries = SG_DEFAULT_RETRIES;
1730
1731         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1732                 return 0;
1733
1734         if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1735             dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1736             !sfp->parentdp->device->host->unchecked_isa_dma &&
1737             blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1738                 md = NULL;
1739         else
1740                 md = &map_data;
1741
1742         if (md) {
1743                 if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1744                         sg_link_reserve(sfp, srp, dxfer_len);
1745                 else {
1746                         res = sg_build_indirect(req_schp, sfp, dxfer_len);
1747                         if (res)
1748                                 return res;
1749                 }
1750
1751                 md->pages = req_schp->pages;
1752                 md->page_order = req_schp->page_order;
1753                 md->nr_entries = req_schp->k_use_sg;
1754                 md->offset = 0;
1755                 md->null_mapped = hp->dxferp ? 0 : 1;
1756                 if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1757                         md->from_user = 1;
1758                 else
1759                         md->from_user = 0;
1760         }
1761
1762         if (iov_count) {
1763                 int len, size = sizeof(struct sg_iovec) * iov_count;
1764                 struct iovec *iov;
1765
1766                 iov = memdup_user(hp->dxferp, size);
1767                 if (IS_ERR(iov))
1768                         return PTR_ERR(iov);
1769
1770                 len = iov_length(iov, iov_count);
1771                 if (hp->dxfer_len < len) {
1772                         iov_count = iov_shorten(iov, iov_count, hp->dxfer_len);
1773                         len = hp->dxfer_len;
1774                 }
1775
1776                 res = blk_rq_map_user_iov(q, rq, md, (struct sg_iovec *)iov,
1777                                           iov_count,
1778                                           len, GFP_ATOMIC);
1779                 kfree(iov);
1780         } else
1781                 res = blk_rq_map_user(q, rq, md, hp->dxferp,
1782                                       hp->dxfer_len, GFP_ATOMIC);
1783
1784         if (!res) {
1785                 srp->bio = rq->bio;
1786
1787                 if (!md) {
1788                         req_schp->dio_in_use = 1;
1789                         hp->info |= SG_INFO_DIRECT_IO;
1790                 }
1791         }
1792         return res;
1793 }
1794
1795 static int
1796 sg_finish_rem_req(Sg_request *srp)
1797 {
1798         int ret = 0;
1799
1800         Sg_fd *sfp = srp->parentfp;
1801         Sg_scatter_hold *req_schp = &srp->data;
1802
1803         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1804                                       "sg_finish_rem_req: res_used=%d\n",
1805                                       (int) srp->res_used));
1806         if (srp->rq) {
1807                 if (srp->bio)
1808                         ret = blk_rq_unmap_user(srp->bio);
1809
1810                 if (srp->rq->cmd != srp->rq->__cmd)
1811                         kfree(srp->rq->cmd);
1812                 blk_put_request(srp->rq);
1813         }
1814
1815         if (srp->res_used)
1816                 sg_unlink_reserve(sfp, srp);
1817         else
1818                 sg_remove_scat(sfp, req_schp);
1819
1820         sg_remove_request(sfp, srp);
1821
1822         return ret;
1823 }
1824
1825 static int
1826 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1827 {
1828         int sg_bufflen = tablesize * sizeof(struct page *);
1829         gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1830
1831         schp->pages = kzalloc(sg_bufflen, gfp_flags);
1832         if (!schp->pages)
1833                 return -ENOMEM;
1834         schp->sglist_len = sg_bufflen;
1835         return tablesize;       /* number of scat_gath elements allocated */
1836 }
1837
1838 static int
1839 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1840 {
1841         int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1842         int sg_tablesize = sfp->parentdp->sg_tablesize;
1843         int blk_size = buff_size, order;
1844         gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1845
1846         if (blk_size < 0)
1847                 return -EFAULT;
1848         if (0 == blk_size)
1849                 ++blk_size;     /* don't know why */
1850         /* round request up to next highest SG_SECTOR_SZ byte boundary */
1851         blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1852         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1853                 "sg_build_indirect: buff_size=%d, blk_size=%d\n",
1854                 buff_size, blk_size));
1855
1856         /* N.B. ret_sz carried into this block ... */
1857         mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1858         if (mx_sc_elems < 0)
1859                 return mx_sc_elems;     /* most likely -ENOMEM */
1860
1861         num = scatter_elem_sz;
1862         if (unlikely(num != scatter_elem_sz_prev)) {
1863                 if (num < PAGE_SIZE) {
1864                         scatter_elem_sz = PAGE_SIZE;
1865                         scatter_elem_sz_prev = PAGE_SIZE;
1866                 } else
1867                         scatter_elem_sz_prev = num;
1868         }
1869
1870         if (sfp->low_dma)
1871                 gfp_mask |= GFP_DMA;
1872
1873         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1874                 gfp_mask |= __GFP_ZERO;
1875
1876         order = get_order(num);
1877 retry:
1878         ret_sz = 1 << (PAGE_SHIFT + order);
1879
1880         for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1881              k++, rem_sz -= ret_sz) {
1882
1883                 num = (rem_sz > scatter_elem_sz_prev) ?
1884                         scatter_elem_sz_prev : rem_sz;
1885
1886                 schp->pages[k] = alloc_pages(gfp_mask, order);
1887                 if (!schp->pages[k])
1888                         goto out;
1889
1890                 if (num == scatter_elem_sz_prev) {
1891                         if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1892                                 scatter_elem_sz = ret_sz;
1893                                 scatter_elem_sz_prev = ret_sz;
1894                         }
1895                 }
1896
1897                 SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1898                                  "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1899                                  k, num, ret_sz));
1900         }               /* end of for loop */
1901
1902         schp->page_order = order;
1903         schp->k_use_sg = k;
1904         SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1905                          "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1906                          k, rem_sz));
1907
1908         schp->bufflen = blk_size;
1909         if (rem_sz > 0) /* must have failed */
1910                 return -ENOMEM;
1911         return 0;
1912 out:
1913         for (i = 0; i < k; i++)
1914                 __free_pages(schp->pages[i], order);
1915
1916         if (--order >= 0)
1917                 goto retry;
1918
1919         return -ENOMEM;
1920 }
1921
1922 static void
1923 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1924 {
1925         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1926                          "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1927         if (schp->pages && schp->sglist_len > 0) {
1928                 if (!schp->dio_in_use) {
1929                         int k;
1930
1931                         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1932                                 SCSI_LOG_TIMEOUT(5,
1933                                         sg_printk(KERN_INFO, sfp->parentdp,
1934                                         "sg_remove_scat: k=%d, pg=0x%p\n",
1935                                         k, schp->pages[k]));
1936                                 __free_pages(schp->pages[k], schp->page_order);
1937                         }
1938
1939                         kfree(schp->pages);
1940                 }
1941         }
1942         memset(schp, 0, sizeof (*schp));
1943 }
1944
1945 static int
1946 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1947 {
1948         Sg_scatter_hold *schp = &srp->data;
1949         int k, num;
1950
1951         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1952                          "sg_read_oxfer: num_read_xfer=%d\n",
1953                          num_read_xfer));
1954         if ((!outp) || (num_read_xfer <= 0))
1955                 return 0;
1956
1957         num = 1 << (PAGE_SHIFT + schp->page_order);
1958         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1959                 if (num > num_read_xfer) {
1960                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1961                                            num_read_xfer))
1962                                 return -EFAULT;
1963                         break;
1964                 } else {
1965                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1966                                            num))
1967                                 return -EFAULT;
1968                         num_read_xfer -= num;
1969                         if (num_read_xfer <= 0)
1970                                 break;
1971                         outp += num;
1972                 }
1973         }
1974
1975         return 0;
1976 }
1977
1978 static void
1979 sg_build_reserve(Sg_fd * sfp, int req_size)
1980 {
1981         Sg_scatter_hold *schp = &sfp->reserve;
1982
1983         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1984                          "sg_build_reserve: req_size=%d\n", req_size));
1985         do {
1986                 if (req_size < PAGE_SIZE)
1987                         req_size = PAGE_SIZE;
1988                 if (0 == sg_build_indirect(schp, sfp, req_size))
1989                         return;
1990                 else
1991                         sg_remove_scat(sfp, schp);
1992                 req_size >>= 1; /* divide by 2 */
1993         } while (req_size > (PAGE_SIZE / 2));
1994 }
1995
1996 static void
1997 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1998 {
1999         Sg_scatter_hold *req_schp = &srp->data;
2000         Sg_scatter_hold *rsv_schp = &sfp->reserve;
2001         int k, num, rem;
2002
2003         srp->res_used = 1;
2004         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2005                          "sg_link_reserve: size=%d\n", size));
2006         rem = size;
2007
2008         num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2009         for (k = 0; k < rsv_schp->k_use_sg; k++) {
2010                 if (rem <= num) {
2011                         req_schp->k_use_sg = k + 1;
2012                         req_schp->sglist_len = rsv_schp->sglist_len;
2013                         req_schp->pages = rsv_schp->pages;
2014
2015                         req_schp->bufflen = size;
2016                         req_schp->page_order = rsv_schp->page_order;
2017                         break;
2018                 } else
2019                         rem -= num;
2020         }
2021
2022         if (k >= rsv_schp->k_use_sg)
2023                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2024                                  "sg_link_reserve: BAD size\n"));
2025 }
2026
2027 static void
2028 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2029 {
2030         Sg_scatter_hold *req_schp = &srp->data;
2031
2032         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2033                                       "sg_unlink_reserve: req->k_use_sg=%d\n",
2034                                       (int) req_schp->k_use_sg));
2035         req_schp->k_use_sg = 0;
2036         req_schp->bufflen = 0;
2037         req_schp->pages = NULL;
2038         req_schp->page_order = 0;
2039         req_schp->sglist_len = 0;
2040         sfp->save_scat_len = 0;
2041         srp->res_used = 0;
2042 }
2043
2044 static Sg_request *
2045 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2046 {
2047         Sg_request *resp;
2048         unsigned long iflags;
2049
2050         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2051         for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2052                 /* look for requests that are ready + not SG_IO owned */
2053                 if ((1 == resp->done) && (!resp->sg_io_owned) &&
2054                     ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2055                         resp->done = 2; /* guard against other readers */
2056                         break;
2057                 }
2058         }
2059         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2060         return resp;
2061 }
2062
2063 /* always adds to end of list */
2064 static Sg_request *
2065 sg_add_request(Sg_fd * sfp)
2066 {
2067         int k;
2068         unsigned long iflags;
2069         Sg_request *resp;
2070         Sg_request *rp = sfp->req_arr;
2071
2072         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2073         resp = sfp->headrp;
2074         if (!resp) {
2075                 memset(rp, 0, sizeof (Sg_request));
2076                 rp->parentfp = sfp;
2077                 resp = rp;
2078                 sfp->headrp = resp;
2079         } else {
2080                 if (0 == sfp->cmd_q)
2081                         resp = NULL;    /* command queuing disallowed */
2082                 else {
2083                         for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2084                                 if (!rp->parentfp)
2085                                         break;
2086                         }
2087                         if (k < SG_MAX_QUEUE) {
2088                                 memset(rp, 0, sizeof (Sg_request));
2089                                 rp->parentfp = sfp;
2090                                 while (resp->nextrp)
2091                                         resp = resp->nextrp;
2092                                 resp->nextrp = rp;
2093                                 resp = rp;
2094                         } else
2095                                 resp = NULL;
2096                 }
2097         }
2098         if (resp) {
2099                 resp->nextrp = NULL;
2100                 resp->header.duration = jiffies_to_msecs(jiffies);
2101         }
2102         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2103         return resp;
2104 }
2105
2106 /* Return of 1 for found; 0 for not found */
2107 static int
2108 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2109 {
2110         Sg_request *prev_rp;
2111         Sg_request *rp;
2112         unsigned long iflags;
2113         int res = 0;
2114
2115         if ((!sfp) || (!srp) || (!sfp->headrp))
2116                 return res;
2117         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2118         prev_rp = sfp->headrp;
2119         if (srp == prev_rp) {
2120                 sfp->headrp = prev_rp->nextrp;
2121                 prev_rp->parentfp = NULL;
2122                 res = 1;
2123         } else {
2124                 while ((rp = prev_rp->nextrp)) {
2125                         if (srp == rp) {
2126                                 prev_rp->nextrp = rp->nextrp;
2127                                 rp->parentfp = NULL;
2128                                 res = 1;
2129                                 break;
2130                         }
2131                         prev_rp = rp;
2132                 }
2133         }
2134         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2135         return res;
2136 }
2137
2138 static Sg_fd *
2139 sg_add_sfp(Sg_device * sdp)
2140 {
2141         Sg_fd *sfp;
2142         unsigned long iflags;
2143         int bufflen;
2144
2145         sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2146         if (!sfp)
2147                 return ERR_PTR(-ENOMEM);
2148
2149         init_waitqueue_head(&sfp->read_wait);
2150         rwlock_init(&sfp->rq_list_lock);
2151
2152         kref_init(&sfp->f_ref);
2153         sfp->timeout = SG_DEFAULT_TIMEOUT;
2154         sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2155         sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2156         sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2157             sdp->device->host->unchecked_isa_dma : 1;
2158         sfp->cmd_q = SG_DEF_COMMAND_Q;
2159         sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2160         sfp->parentdp = sdp;
2161         write_lock_irqsave(&sdp->sfd_lock, iflags);
2162         if (atomic_read(&sdp->detaching)) {
2163                 write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2164                 return ERR_PTR(-ENODEV);
2165         }
2166         list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2167         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2168         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2169                                       "sg_add_sfp: sfp=0x%p\n", sfp));
2170         if (unlikely(sg_big_buff != def_reserved_size))
2171                 sg_big_buff = def_reserved_size;
2172
2173         bufflen = min_t(int, sg_big_buff,
2174                         max_sectors_bytes(sdp->device->request_queue));
2175         sg_build_reserve(sfp, bufflen);
2176         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2177                                       "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2178                                       sfp->reserve.bufflen,
2179                                       sfp->reserve.k_use_sg));
2180
2181         kref_get(&sdp->d_ref);
2182         __module_get(THIS_MODULE);
2183         return sfp;
2184 }
2185
2186 static void
2187 sg_remove_sfp_usercontext(struct work_struct *work)
2188 {
2189         struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2190         struct sg_device *sdp = sfp->parentdp;
2191
2192         /* Cleanup any responses which were never read(). */
2193         while (sfp->headrp)
2194                 sg_finish_rem_req(sfp->headrp);
2195
2196         if (sfp->reserve.bufflen > 0) {
2197                 SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2198                                 "sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2199                                 (int) sfp->reserve.bufflen,
2200                                 (int) sfp->reserve.k_use_sg));
2201                 sg_remove_scat(sfp, &sfp->reserve);
2202         }
2203
2204         SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2205                         "sg_remove_sfp: sfp=0x%p\n", sfp));
2206         kfree(sfp);
2207
2208         scsi_device_put(sdp->device);
2209         kref_put(&sdp->d_ref, sg_device_destroy);
2210         module_put(THIS_MODULE);
2211 }
2212
2213 static void
2214 sg_remove_sfp(struct kref *kref)
2215 {
2216         struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2217         struct sg_device *sdp = sfp->parentdp;
2218         unsigned long iflags;
2219
2220         write_lock_irqsave(&sdp->sfd_lock, iflags);
2221         list_del(&sfp->sfd_siblings);
2222         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2223
2224         INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2225         schedule_work(&sfp->ew.work);
2226 }
2227
2228 static int
2229 sg_res_in_use(Sg_fd * sfp)
2230 {
2231         const Sg_request *srp;
2232         unsigned long iflags;
2233
2234         read_lock_irqsave(&sfp->rq_list_lock, iflags);
2235         for (srp = sfp->headrp; srp; srp = srp->nextrp)
2236                 if (srp->res_used)
2237                         break;
2238         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2239         return srp ? 1 : 0;
2240 }
2241
2242 #ifdef CONFIG_SCSI_PROC_FS
2243 static int
2244 sg_idr_max_id(int id, void *p, void *data)
2245 {
2246         int *k = data;
2247
2248         if (*k < id)
2249                 *k = id;
2250
2251         return 0;
2252 }
2253
2254 static int
2255 sg_last_dev(void)
2256 {
2257         int k = -1;
2258         unsigned long iflags;
2259
2260         read_lock_irqsave(&sg_index_lock, iflags);
2261         idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2262         read_unlock_irqrestore(&sg_index_lock, iflags);
2263         return k + 1;           /* origin 1 */
2264 }
2265 #endif
2266
2267 /* must be called with sg_index_lock held */
2268 static Sg_device *sg_lookup_dev(int dev)
2269 {
2270         return idr_find(&sg_index_idr, dev);
2271 }
2272
2273 static Sg_device *
2274 sg_get_dev(int dev)
2275 {
2276         struct sg_device *sdp;
2277         unsigned long flags;
2278
2279         read_lock_irqsave(&sg_index_lock, flags);
2280         sdp = sg_lookup_dev(dev);
2281         if (!sdp)
2282                 sdp = ERR_PTR(-ENXIO);
2283         else if (atomic_read(&sdp->detaching)) {
2284                 /* If sdp->detaching, then the refcount may already be 0, in
2285                  * which case it would be a bug to do kref_get().
2286                  */
2287                 sdp = ERR_PTR(-ENODEV);
2288         } else
2289                 kref_get(&sdp->d_ref);
2290         read_unlock_irqrestore(&sg_index_lock, flags);
2291
2292         return sdp;
2293 }
2294
2295 #ifdef CONFIG_SCSI_PROC_FS
2296
2297 static struct proc_dir_entry *sg_proc_sgp = NULL;
2298
2299 static char sg_proc_sg_dirname[] = "scsi/sg";
2300
2301 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2302
2303 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2304 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2305                                   size_t count, loff_t *off);
2306 static const struct file_operations adio_fops = {
2307         .owner = THIS_MODULE,
2308         .open = sg_proc_single_open_adio,
2309         .read = seq_read,
2310         .llseek = seq_lseek,
2311         .write = sg_proc_write_adio,
2312         .release = single_release,
2313 };
2314
2315 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2316 static ssize_t sg_proc_write_dressz(struct file *filp,
2317                 const char __user *buffer, size_t count, loff_t *off);
2318 static const struct file_operations dressz_fops = {
2319         .owner = THIS_MODULE,
2320         .open = sg_proc_single_open_dressz,
2321         .read = seq_read,
2322         .llseek = seq_lseek,
2323         .write = sg_proc_write_dressz,
2324         .release = single_release,
2325 };
2326
2327 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2328 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2329 static const struct file_operations version_fops = {
2330         .owner = THIS_MODULE,
2331         .open = sg_proc_single_open_version,
2332         .read = seq_read,
2333         .llseek = seq_lseek,
2334         .release = single_release,
2335 };
2336
2337 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2338 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2339 static const struct file_operations devhdr_fops = {
2340         .owner = THIS_MODULE,
2341         .open = sg_proc_single_open_devhdr,
2342         .read = seq_read,
2343         .llseek = seq_lseek,
2344         .release = single_release,
2345 };
2346
2347 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2348 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2349 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2350 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2351 static void dev_seq_stop(struct seq_file *s, void *v);
2352 static const struct file_operations dev_fops = {
2353         .owner = THIS_MODULE,
2354         .open = sg_proc_open_dev,
2355         .read = seq_read,
2356         .llseek = seq_lseek,
2357         .release = seq_release,
2358 };
2359 static const struct seq_operations dev_seq_ops = {
2360         .start = dev_seq_start,
2361         .next  = dev_seq_next,
2362         .stop  = dev_seq_stop,
2363         .show  = sg_proc_seq_show_dev,
2364 };
2365
2366 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2367 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2368 static const struct file_operations devstrs_fops = {
2369         .owner = THIS_MODULE,
2370         .open = sg_proc_open_devstrs,
2371         .read = seq_read,
2372         .llseek = seq_lseek,
2373         .release = seq_release,
2374 };
2375 static const struct seq_operations devstrs_seq_ops = {
2376         .start = dev_seq_start,
2377         .next  = dev_seq_next,
2378         .stop  = dev_seq_stop,
2379         .show  = sg_proc_seq_show_devstrs,
2380 };
2381
2382 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2383 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2384 static const struct file_operations debug_fops = {
2385         .owner = THIS_MODULE,
2386         .open = sg_proc_open_debug,
2387         .read = seq_read,
2388         .llseek = seq_lseek,
2389         .release = seq_release,
2390 };
2391 static const struct seq_operations debug_seq_ops = {
2392         .start = dev_seq_start,
2393         .next  = dev_seq_next,
2394         .stop  = dev_seq_stop,
2395         .show  = sg_proc_seq_show_debug,
2396 };
2397
2398
2399 struct sg_proc_leaf {
2400         const char * name;
2401         const struct file_operations * fops;
2402 };
2403
2404 static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
2405         {"allow_dio", &adio_fops},
2406         {"debug", &debug_fops},
2407         {"def_reserved_size", &dressz_fops},
2408         {"device_hdr", &devhdr_fops},
2409         {"devices", &dev_fops},
2410         {"device_strs", &devstrs_fops},
2411         {"version", &version_fops}
2412 };
2413
2414 static int
2415 sg_proc_init(void)
2416 {
2417         int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2418         int k;
2419
2420         sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2421         if (!sg_proc_sgp)
2422                 return 1;
2423         for (k = 0; k < num_leaves; ++k) {
2424                 const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2425                 umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2426                 proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2427         }
2428         return 0;
2429 }
2430
2431 static void
2432 sg_proc_cleanup(void)
2433 {
2434         int k;
2435         int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2436
2437         if (!sg_proc_sgp)
2438                 return;
2439         for (k = 0; k < num_leaves; ++k)
2440                 remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2441         remove_proc_entry(sg_proc_sg_dirname, NULL);
2442 }
2443
2444
2445 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2446 {
2447         seq_printf(s, "%d\n", *((int *)s->private));
2448         return 0;
2449 }
2450
2451 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2452 {
2453         return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2454 }
2455
2456 static ssize_t
2457 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2458                    size_t count, loff_t *off)
2459 {
2460         int err;
2461         unsigned long num;
2462
2463         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2464                 return -EACCES;
2465         err = kstrtoul_from_user(buffer, count, 0, &num);
2466         if (err)
2467                 return err;
2468         sg_allow_dio = num ? 1 : 0;
2469         return count;
2470 }
2471
2472 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2473 {
2474         return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2475 }
2476
2477 static ssize_t
2478 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2479                      size_t count, loff_t *off)
2480 {
2481         int err;
2482         unsigned long k = ULONG_MAX;
2483
2484         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2485                 return -EACCES;
2486
2487         err = kstrtoul_from_user(buffer, count, 0, &k);
2488         if (err)
2489                 return err;
2490         if (k <= 1048576) {     /* limit "big buff" to 1 MB */
2491                 sg_big_buff = k;
2492                 return count;
2493         }
2494         return -ERANGE;
2495 }
2496
2497 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2498 {
2499         seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2500                    sg_version_date);
2501         return 0;
2502 }
2503
2504 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2505 {
2506         return single_open(file, sg_proc_seq_show_version, NULL);
2507 }
2508
2509 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2510 {
2511         seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2512         return 0;
2513 }
2514
2515 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2516 {
2517         return single_open(file, sg_proc_seq_show_devhdr, NULL);
2518 }
2519
2520 struct sg_proc_deviter {
2521         loff_t  index;
2522         size_t  max;
2523 };
2524
2525 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2526 {
2527         struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2528
2529         s->private = it;
2530         if (! it)
2531                 return NULL;
2532
2533         it->index = *pos;
2534         it->max = sg_last_dev();
2535         if (it->index >= it->max)
2536                 return NULL;
2537         return it;
2538 }
2539
2540 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2541 {
2542         struct sg_proc_deviter * it = s->private;
2543
2544         *pos = ++it->index;
2545         return (it->index < it->max) ? it : NULL;
2546 }
2547
2548 static void dev_seq_stop(struct seq_file *s, void *v)
2549 {
2550         kfree(s->private);
2551 }
2552
2553 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2554 {
2555         return seq_open(file, &dev_seq_ops);
2556 }
2557
2558 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2559 {
2560         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2561         Sg_device *sdp;
2562         struct scsi_device *scsidp;
2563         unsigned long iflags;
2564
2565         read_lock_irqsave(&sg_index_lock, iflags);
2566         sdp = it ? sg_lookup_dev(it->index) : NULL;
2567         if ((NULL == sdp) || (NULL == sdp->device) ||
2568             (atomic_read(&sdp->detaching)))
2569                 seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2570         else {
2571                 scsidp = sdp->device;
2572                 seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2573                               scsidp->host->host_no, scsidp->channel,
2574                               scsidp->id, scsidp->lun, (int) scsidp->type,
2575                               1,
2576                               (int) scsidp->queue_depth,
2577                               (int) atomic_read(&scsidp->device_busy),
2578                               (int) scsi_device_online(scsidp));
2579         }
2580         read_unlock_irqrestore(&sg_index_lock, iflags);
2581         return 0;
2582 }
2583
2584 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2585 {
2586         return seq_open(file, &devstrs_seq_ops);
2587 }
2588
2589 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2590 {
2591         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2592         Sg_device *sdp;
2593         struct scsi_device *scsidp;
2594         unsigned long iflags;
2595
2596         read_lock_irqsave(&sg_index_lock, iflags);
2597         sdp = it ? sg_lookup_dev(it->index) : NULL;
2598         scsidp = sdp ? sdp->device : NULL;
2599         if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2600                 seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2601                            scsidp->vendor, scsidp->model, scsidp->rev);
2602         else
2603                 seq_puts(s, "<no active device>\n");
2604         read_unlock_irqrestore(&sg_index_lock, iflags);
2605         return 0;
2606 }
2607
2608 /* must be called while holding sg_index_lock */
2609 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2610 {
2611         int k, m, new_interface, blen, usg;
2612         Sg_request *srp;
2613         Sg_fd *fp;
2614         const sg_io_hdr_t *hp;
2615         const char * cp;
2616         unsigned int ms;
2617
2618         k = 0;
2619         list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2620                 k++;
2621                 read_lock(&fp->rq_list_lock); /* irqs already disabled */
2622                 seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2623                            "(res)sgat=%d low_dma=%d\n", k,
2624                            jiffies_to_msecs(fp->timeout),
2625                            fp->reserve.bufflen,
2626                            (int) fp->reserve.k_use_sg,
2627                            (int) fp->low_dma);
2628                 seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2629                            (int) fp->cmd_q, (int) fp->force_packid,
2630                            (int) fp->keep_orphan);
2631                 for (m = 0, srp = fp->headrp;
2632                                 srp != NULL;
2633                                 ++m, srp = srp->nextrp) {
2634                         hp = &srp->header;
2635                         new_interface = (hp->interface_id == '\0') ? 0 : 1;
2636                         if (srp->res_used) {
2637                                 if (new_interface &&
2638                                     (SG_FLAG_MMAP_IO & hp->flags))
2639                                         cp = "     mmap>> ";
2640                                 else
2641                                         cp = "     rb>> ";
2642                         } else {
2643                                 if (SG_INFO_DIRECT_IO_MASK & hp->info)
2644                                         cp = "     dio>> ";
2645                                 else
2646                                         cp = "     ";
2647                         }
2648                         seq_puts(s, cp);
2649                         blen = srp->data.bufflen;
2650                         usg = srp->data.k_use_sg;
2651                         seq_puts(s, srp->done ?
2652                                  ((1 == srp->done) ?  "rcv:" : "fin:")
2653                                   : "act:");
2654                         seq_printf(s, " id=%d blen=%d",
2655                                    srp->header.pack_id, blen);
2656                         if (srp->done)
2657                                 seq_printf(s, " dur=%d", hp->duration);
2658                         else {
2659                                 ms = jiffies_to_msecs(jiffies);
2660                                 seq_printf(s, " t_o/elap=%d/%d",
2661                                         (new_interface ? hp->timeout :
2662                                                   jiffies_to_msecs(fp->timeout)),
2663                                         (ms > hp->duration ? ms - hp->duration : 0));
2664                         }
2665                         seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2666                                    (int) srp->data.cmd_opcode);
2667                 }
2668                 if (0 == m)
2669                         seq_puts(s, "     No requests active\n");
2670                 read_unlock(&fp->rq_list_lock);
2671         }
2672 }
2673
2674 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2675 {
2676         return seq_open(file, &debug_seq_ops);
2677 }
2678
2679 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2680 {
2681         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2682         Sg_device *sdp;
2683         unsigned long iflags;
2684
2685         if (it && (0 == it->index))
2686                 seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2687                            (int)it->max, sg_big_buff);
2688
2689         read_lock_irqsave(&sg_index_lock, iflags);
2690         sdp = it ? sg_lookup_dev(it->index) : NULL;
2691         if (NULL == sdp)
2692                 goto skip;
2693         read_lock(&sdp->sfd_lock);
2694         if (!list_empty(&sdp->sfds)) {
2695                 seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2696                 if (atomic_read(&sdp->detaching))
2697                         seq_puts(s, "detaching pending close ");
2698                 else if (sdp->device) {
2699                         struct scsi_device *scsidp = sdp->device;
2700
2701                         seq_printf(s, "%d:%d:%d:%llu   em=%d",
2702                                    scsidp->host->host_no,
2703                                    scsidp->channel, scsidp->id,
2704                                    scsidp->lun,
2705                                    scsidp->host->hostt->emulated);
2706                 }
2707                 seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2708                            sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2709                 sg_proc_debug_helper(s, sdp);
2710         }
2711         read_unlock(&sdp->sfd_lock);
2712 skip:
2713         read_unlock_irqrestore(&sg_index_lock, iflags);
2714         return 0;
2715 }
2716
2717 #endif                          /* CONFIG_SCSI_PROC_FS */
2718
2719 module_init(init_sg);
2720 module_exit(exit_sg);