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/errno.h>
  37 #include <linux/mtio.h>
  38 #include <linux/ioctl.h>
  39 #include <linux/slab.h>
  40 #include <linux/fcntl.h>
  41 #include <linux/init.h>
  42 #include <linux/poll.h>
  43 #include <linux/moduleparam.h>
  44 #include <linux/cdev.h>
  45 #include <linux/idr.h>
  46 #include <linux/seq_file.h>
  47 #include <linux/blkdev.h>
  48 #include <linux/delay.h>
  49 #include <linux/blktrace_api.h>
  50 #include <linux/mutex.h>
  51 #include <linux/atomic.h>
  52 #include <linux/ratelimit.h>
  53 #include <linux/uio.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 #define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
  83
  84 int sg_big_buff = SG_DEF_RESERVED_SIZE;
  85 /* N.B. This variable is readable and writeable via
  86    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
  87    of this size (or less if there is not enough memory) will be reserved
  88    for use by this file descriptor. [Deprecated usage: this variable is also
  89    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
  90    the kernel (i.e. it is not a module).] */
  91 static int def_reserved_size = -1;      /* picks up init parameter */
  92 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
  93
  94 static int scatter_elem_sz = SG_SCATTER_SZ;
  95 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
  96
  97 #define SG_SECTOR_SZ 512
  98
  99 static int sg_add_device(struct device *, struct class_interface *);
 100 static void sg_remove_device(struct device *, struct class_interface *);
 101
 102 static DEFINE_IDR(sg_index_idr);
 103 static DEFINE_RWLOCK(sg_index_lock);    /* Also used to lock
 104                                                            file descriptor list for device */
 105
 106 static struct class_interface sg_interface = {
 107         .add_dev        = sg_add_device,
 108         .remove_dev     = sg_remove_device,
 109 };
 110
 111 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
 112         unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
 113         unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
 114         unsigned bufflen;       /* Size of (aggregate) data buffer */
 115         struct page **pages;
 116         int page_order;
 117         char dio_in_use;        /* 0->indirect IO (or mmap), 1->dio */
 118         unsigned char cmd_opcode; /* first byte of command */
 119 } Sg_scatter_hold;
 120
 121 struct sg_device;               /* forward declarations */
 122 struct sg_fd;
 123
 124 typedef struct sg_request {     /* SG_MAX_QUEUE requests outstanding per file */
 125         struct sg_request *nextrp;      /* NULL -> tail request (slist) */
 126         struct sg_fd *parentfp; /* NULL -> not in use */
 127         Sg_scatter_hold data;   /* hold buffer, perhaps scatter list */
 128         sg_io_hdr_t header;     /* scsi command+info, see <scsi/sg.h> */
 129         unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
 130         char res_used;          /* 1 -> using reserve buffer, 0 -> not ... */
 131         char orphan;            /* 1 -> drop on sight, 0 -> normal */
 132         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
 133         /* done protected by rq_list_lock */
 134         char done;              /* 0->before bh, 1->before read, 2->read */
 135         struct request *rq;
 136         struct bio *bio;
 137         struct execute_work ew;
 138 } Sg_request;
 139
 140 typedef struct sg_fd {          /* holds the state of a file descriptor */
 141         struct list_head sfd_siblings;  /* protected by device's sfd_lock */
 142         struct sg_device *parentdp;     /* owning device */
 143         wait_queue_head_t read_wait;    /* queue read until command done */
 144         rwlock_t rq_list_lock;  /* protect access to list in req_arr */
 145         int timeout;            /* defaults to SG_DEFAULT_TIMEOUT      */
 146         int timeout_user;       /* defaults to SG_DEFAULT_TIMEOUT_USER */
 147         Sg_scatter_hold reserve;        /* buffer held for this file descriptor */
 148         unsigned save_scat_len; /* original length of trunc. scat. element */
 149         Sg_request *headrp;     /* head of request slist, NULL->empty */
 150         struct fasync_struct *async_qp; /* used by asynchronous notification */
 151         Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
 152         char low_dma;           /* as in parent but possibly overridden to 1 */
 153         char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
 154         char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
 155         unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
 156         char keep_orphan;       /* 0 -> drop orphan (def), 1 -> keep for read() */
 157         char mmap_called;       /* 0 -> mmap() never called on this fd */
 158         struct kref f_ref;
 159         struct execute_work ew;
 160 } Sg_fd;
 161
 162 typedef struct sg_device { /* holds the state of each scsi generic device */
 163         struct scsi_device *device;
 164         wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
 165         struct mutex open_rel_lock;     /* held when in open() or release() */
 166         int sg_tablesize;       /* adapter's max scatter-gather table size */
 167         u32 index;              /* device index number */
 168         struct list_head sfds;
 169         rwlock_t sfd_lock;      /* protect access to sfd list */
 170         atomic_t detaching;     /* 0->device usable, 1->device detaching */
 171         bool exclude;           /* 1->open(O_EXCL) succeeded and is active */
 172         int open_cnt;           /* count of opens (perhaps < num(sfds) ) */
 173         char sgdebug;           /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
 174         struct gendisk *disk;
 175         struct cdev * cdev;     /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
 176         struct kref d_ref;
 177 } Sg_device;
 178
 179 /* tasklet or soft irq callback */
 180 static void sg_rq_end_io(struct request *rq, int uptodate);
 181 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 182 static int sg_finish_rem_req(Sg_request * srp);
 183 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 184 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 185                            Sg_request * srp);
 186 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
 187                         const char __user *buf, size_t count, int blocking,
 188                         int read_only, int sg_io_owned, Sg_request **o_srp);
 189 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 190                            unsigned char *cmnd, int timeout, int blocking);
 191 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
 192 static void sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp);
 193 static void sg_build_reserve(Sg_fd * sfp, int req_size);
 194 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
 195 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
 196 static Sg_fd *sg_add_sfp(Sg_device * sdp);
 197 static void sg_remove_sfp(struct kref *);
 198 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
 199 static Sg_request *sg_add_request(Sg_fd * sfp);
 200 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 201 static int sg_res_in_use(Sg_fd * sfp);
 202 static Sg_device *sg_get_dev(int dev);
 203 static void sg_device_destroy(struct kref *kref);
 204
 205 #define SZ_SG_HEADER sizeof(struct sg_header)
 206 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
 207 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
 208 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
 209
 210 #define sg_printk(prefix, sdp, fmt, a...) \
 211         sdev_prefix_printk(prefix, (sdp)->device,               \
 212                            (sdp)->disk->disk_name, fmt, ##a)
 213
 214 static int sg_allow_access(struct file *filp, unsigned char *cmd)
 215 {
 216         struct sg_fd *sfp = filp->private_data;
 217
 218         if (sfp->parentdp->device->type == TYPE_SCANNER)
 219                 return 0;
 220
 221         return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
 222 }
 223
 224 static int
 225 open_wait(Sg_device *sdp, int flags)
 226 {
 227         int retval = 0;
 228
 229         if (flags & O_EXCL) {
 230                 while (sdp->open_cnt > 0) {
 231                         mutex_unlock(&sdp->open_rel_lock);
 232                         retval = wait_event_interruptible(sdp->open_wait,
 233                                         (atomic_read(&sdp->detaching) ||
 234                                          !sdp->open_cnt));
 235                         mutex_lock(&sdp->open_rel_lock);
 236
 237                         if (retval) /* -ERESTARTSYS */
 238                                 return retval;
 239                         if (atomic_read(&sdp->detaching))
 240                                 return -ENODEV;
 241                 }
 242         } else {
 243                 while (sdp->exclude) {
 244                         mutex_unlock(&sdp->open_rel_lock);
 245                         retval = wait_event_interruptible(sdp->open_wait,
 246                                         (atomic_read(&sdp->detaching) ||
 247                                          !sdp->exclude));
 248                         mutex_lock(&sdp->open_rel_lock);
 249
 250                         if (retval) /* -ERESTARTSYS */
 251                                 return retval;
 252                         if (atomic_read(&sdp->detaching))
 253                                 return -ENODEV;
 254                 }
 255         }
 256
 257         return retval;
 258 }
 259
 260 /* Returns 0 on success, else a negated errno value */
 261 static int
 262 sg_open(struct inode *inode, struct file *filp)
 263 {
 264         int dev = iminor(inode);
 265         int flags = filp->f_flags;
 266         struct request_queue *q;
 267         Sg_device *sdp;
 268         Sg_fd *sfp;
 269         int retval;
 270
 271         nonseekable_open(inode, filp);
 272         if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
 273                 return -EPERM; /* Can't lock it with read only access */
 274         sdp = sg_get_dev(dev);
 275         if (IS_ERR(sdp))
 276                 return PTR_ERR(sdp);
 277
 278         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 279                                       "sg_open: flags=0x%x\n", flags));
 280
 281         /* This driver's module count bumped by fops_get in <linux/fs.h> */
 282         /* Prevent the device driver from vanishing while we sleep */
 283         retval = scsi_device_get(sdp->device);
 284         if (retval)
 285                 goto sg_put;
 286
 287         retval = scsi_autopm_get_device(sdp->device);
 288         if (retval)
 289                 goto sdp_put;
 290
 291         /* scsi_block_when_processing_errors() may block so bypass
 292          * check if O_NONBLOCK. Permits SCSI commands to be issued
 293          * during error recovery. Tread carefully. */
 294         if (!((flags & O_NONBLOCK) ||
 295               scsi_block_when_processing_errors(sdp->device))) {
 296                 retval = -ENXIO;
 297                 /* we are in error recovery for this device */
 298                 goto error_out;
 299         }
 300
 301         mutex_lock(&sdp->open_rel_lock);
 302         if (flags & O_NONBLOCK) {
 303                 if (flags & O_EXCL) {
 304                         if (sdp->open_cnt > 0) {
 305                                 retval = -EBUSY;
 306                                 goto error_mutex_locked;
 307                         }
 308                 } else {
 309                         if (sdp->exclude) {
 310                                 retval = -EBUSY;
 311                                 goto error_mutex_locked;
 312                         }
 313                 }
 314         } else {
 315                 retval = open_wait(sdp, flags);
 316                 if (retval) /* -ERESTARTSYS or -ENODEV */
 317                         goto error_mutex_locked;
 318         }
 319
 320         /* N.B. at this point we are holding the open_rel_lock */
 321         if (flags & O_EXCL)
 322                 sdp->exclude = true;
 323
 324         if (sdp->open_cnt < 1) {  /* no existing opens */
 325                 sdp->sgdebug = 0;
 326                 q = sdp->device->request_queue;
 327                 sdp->sg_tablesize = queue_max_segments(q);
 328         }
 329         sfp = sg_add_sfp(sdp);
 330         if (IS_ERR(sfp)) {
 331                 retval = PTR_ERR(sfp);
 332                 goto out_undo;
 333         }
 334
 335         filp->private_data = sfp;
 336         sdp->open_cnt++;
 337         mutex_unlock(&sdp->open_rel_lock);
 338
 339         retval = 0;
 340 sg_put:
 341         kref_put(&sdp->d_ref, sg_device_destroy);
 342         return retval;
 343
 344 out_undo:
 345         if (flags & O_EXCL) {
 346                 sdp->exclude = false;   /* undo if error */
 347                 wake_up_interruptible(&sdp->open_wait);
 348         }
 349 error_mutex_locked:
 350         mutex_unlock(&sdp->open_rel_lock);
 351 error_out:
 352         scsi_autopm_put_device(sdp->device);
 353 sdp_put:
 354         scsi_device_put(sdp->device);
 355         goto sg_put;
 356 }
 357
 358 /* Release resources associated with a successful sg_open()
 359  * Returns 0 on success, else a negated errno value */
 360 static int
 361 sg_release(struct inode *inode, struct file *filp)
 362 {
 363         Sg_device *sdp;
 364         Sg_fd *sfp;
 365
 366         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 367                 return -ENXIO;
 368         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
 369
 370         mutex_lock(&sdp->open_rel_lock);
 371         scsi_autopm_put_device(sdp->device);
 372         kref_put(&sfp->f_ref, sg_remove_sfp);
 373         sdp->open_cnt--;
 374
 375         /* possibly many open()s waiting on exlude clearing, start many;
 376          * only open(O_EXCL)s wait on 0==open_cnt so only start one */
 377         if (sdp->exclude) {
 378                 sdp->exclude = false;
 379                 wake_up_interruptible_all(&sdp->open_wait);
 380         } else if (0 == sdp->open_cnt) {
 381                 wake_up_interruptible(&sdp->open_wait);
 382         }
 383         mutex_unlock(&sdp->open_rel_lock);
 384         return 0;
 385 }
 386
 387 static ssize_t
 388 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
 389 {
 390         Sg_device *sdp;
 391         Sg_fd *sfp;
 392         Sg_request *srp;
 393         int req_pack_id = -1;
 394         sg_io_hdr_t *hp;
 395         struct sg_header *old_hdr = NULL;
 396         int retval = 0;
 397
 398         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 399                 return -ENXIO;
 400         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 401                                       "sg_read: count=%d\n", (int) count));
 402
 403         if (!access_ok(VERIFY_WRITE, buf, count))
 404                 return -EFAULT;
 405         if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
 406                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 407                 if (!old_hdr)
 408                         return -ENOMEM;
 409                 if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
 410                         retval = -EFAULT;
 411                         goto free_old_hdr;
 412                 }
 413                 if (old_hdr->reply_len < 0) {
 414                         if (count >= SZ_SG_IO_HDR) {
 415                                 sg_io_hdr_t *new_hdr;
 416                                 new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
 417                                 if (!new_hdr) {
 418                                         retval = -ENOMEM;
 419                                         goto free_old_hdr;
 420                                 }
 421                                 retval =__copy_from_user
 422                                     (new_hdr, buf, SZ_SG_IO_HDR);
 423                                 req_pack_id = new_hdr->pack_id;
 424                                 kfree(new_hdr);
 425                                 if (retval) {
 426                                         retval = -EFAULT;
 427                                         goto free_old_hdr;
 428                                 }
 429                         }
 430                 } else
 431                         req_pack_id = old_hdr->pack_id;
 432         }
 433         srp = sg_get_rq_mark(sfp, req_pack_id);
 434         if (!srp) {             /* now wait on packet to arrive */
 435                 if (atomic_read(&sdp->detaching)) {
 436                         retval = -ENODEV;
 437                         goto free_old_hdr;
 438                 }
 439                 if (filp->f_flags & O_NONBLOCK) {
 440                         retval = -EAGAIN;
 441                         goto free_old_hdr;
 442                 }
 443                 retval = wait_event_interruptible(sfp->read_wait,
 444                         (atomic_read(&sdp->detaching) ||
 445                         (srp = sg_get_rq_mark(sfp, req_pack_id))));
 446                 if (atomic_read(&sdp->detaching)) {
 447                         retval = -ENODEV;
 448                         goto free_old_hdr;
 449                 }
 450                 if (retval) {
 451                         /* -ERESTARTSYS as signal hit process */
 452                         goto free_old_hdr;
 453                 }
 454         }
 455         if (srp->header.interface_id != '\0') {
 456                 retval = sg_new_read(sfp, buf, count, srp);
 457                 goto free_old_hdr;
 458         }
 459
 460         hp = &srp->header;
 461         if (old_hdr == NULL) {
 462                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 463                 if (! old_hdr) {
 464                         retval = -ENOMEM;
 465                         goto free_old_hdr;
 466                 }
 467         }
 468         memset(old_hdr, 0, SZ_SG_HEADER);
 469         old_hdr->reply_len = (int) hp->timeout;
 470         old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
 471         old_hdr->pack_id = hp->pack_id;
 472         old_hdr->twelve_byte =
 473             ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
 474         old_hdr->target_status = hp->masked_status;
 475         old_hdr->host_status = hp->host_status;
 476         old_hdr->driver_status = hp->driver_status;
 477         if ((CHECK_CONDITION & hp->masked_status) ||
 478             (DRIVER_SENSE & hp->driver_status))
 479                 memcpy(old_hdr->sense_buffer, srp->sense_b,
 480                        sizeof (old_hdr->sense_buffer));
 481         switch (hp->host_status) {
 482         /* This setup of 'result' is for backward compatibility and is best
 483            ignored by the user who should use target, host + driver status */
 484         case DID_OK:
 485         case DID_PASSTHROUGH:
 486         case DID_SOFT_ERROR:
 487                 old_hdr->result = 0;
 488                 break;
 489         case DID_NO_CONNECT:
 490         case DID_BUS_BUSY:
 491         case DID_TIME_OUT:
 492                 old_hdr->result = EBUSY;
 493                 break;
 494         case DID_BAD_TARGET:
 495         case DID_ABORT:
 496         case DID_PARITY:
 497         case DID_RESET:
 498         case DID_BAD_INTR:
 499                 old_hdr->result = EIO;
 500                 break;
 501         case DID_ERROR:
 502                 old_hdr->result = (srp->sense_b[0] == 0 &&
 503                                   hp->masked_status == GOOD) ? 0 : EIO;
 504                 break;
 505         default:
 506                 old_hdr->result = EIO;
 507                 break;
 508         }
 509
 510         /* Now copy the result back to the user buffer.  */
 511         if (count >= SZ_SG_HEADER) {
 512                 if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
 513                         retval = -EFAULT;
 514                         goto free_old_hdr;
 515                 }
 516                 buf += SZ_SG_HEADER;
 517                 if (count > old_hdr->reply_len)
 518                         count = old_hdr->reply_len;
 519                 if (count > SZ_SG_HEADER) {
 520                         if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
 521                                 retval = -EFAULT;
 522                                 goto free_old_hdr;
 523                         }
 524                 }
 525         } else
 526                 count = (old_hdr->result == 0) ? 0 : -EIO;
 527         sg_finish_rem_req(srp);
 528         retval = count;
 529 free_old_hdr:
 530         kfree(old_hdr);
 531         return retval;
 532 }
 533
 534 static ssize_t
 535 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
 536 {
 537         sg_io_hdr_t *hp = &srp->header;
 538         int err = 0, err2;
 539         int len;
 540
 541         if (count < SZ_SG_IO_HDR) {
 542                 err = -EINVAL;
 543                 goto err_out;
 544         }
 545         hp->sb_len_wr = 0;
 546         if ((hp->mx_sb_len > 0) && hp->sbp) {
 547                 if ((CHECK_CONDITION & hp->masked_status) ||
 548                     (DRIVER_SENSE & hp->driver_status)) {
 549                         int sb_len = SCSI_SENSE_BUFFERSIZE;
 550                         sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
 551                         len = 8 + (int) srp->sense_b[7];        /* Additional sense length field */
 552                         len = (len > sb_len) ? sb_len : len;
 553                         if (copy_to_user(hp->sbp, srp->sense_b, len)) {
 554                                 err = -EFAULT;
 555                                 goto err_out;
 556                         }
 557                         hp->sb_len_wr = len;
 558                 }
 559         }
 560         if (hp->masked_status || hp->host_status || hp->driver_status)
 561                 hp->info |= SG_INFO_CHECK;
 562         if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
 563                 err = -EFAULT;
 564                 goto err_out;
 565         }
 566 err_out:
 567         err2 = sg_finish_rem_req(srp);
 568         return err ? : err2 ? : count;
 569 }
 570
 571 static ssize_t
 572 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 573 {
 574         int mxsize, cmd_size, k;
 575         int input_size, blocking;
 576         unsigned char opcode;
 577         Sg_device *sdp;
 578         Sg_fd *sfp;
 579         Sg_request *srp;
 580         struct sg_header old_hdr;
 581         sg_io_hdr_t *hp;
 582         unsigned char cmnd[SG_MAX_CDB_SIZE];
 583
 584         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 585                 return -ENXIO;
 586         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 587                                       "sg_write: count=%d\n", (int) count));
 588         if (atomic_read(&sdp->detaching))
 589                 return -ENODEV;
 590         if (!((filp->f_flags & O_NONBLOCK) ||
 591               scsi_block_when_processing_errors(sdp->device)))
 592                 return -ENXIO;
 593
 594         if (!access_ok(VERIFY_READ, buf, count))
 595                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 596         if (count < SZ_SG_HEADER)
 597                 return -EIO;
 598         if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
 599                 return -EFAULT;
 600         blocking = !(filp->f_flags & O_NONBLOCK);
 601         if (old_hdr.reply_len < 0)
 602                 return sg_new_write(sfp, filp, buf, count,
 603                                     blocking, 0, 0, NULL);
 604         if (count < (SZ_SG_HEADER + 6))
 605                 return -EIO;    /* The minimum scsi command length is 6 bytes. */
 606
 607         if (!(srp = sg_add_request(sfp))) {
 608                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 609                                               "sg_write: queue full\n"));
 610                 return -EDOM;
 611         }
 612         buf += SZ_SG_HEADER;
 613         __get_user(opcode, buf);
 614         if (sfp->next_cmd_len > 0) {
 615                 cmd_size = sfp->next_cmd_len;
 616                 sfp->next_cmd_len = 0;  /* reset so only this write() effected */
 617         } else {
 618                 cmd_size = COMMAND_SIZE(opcode);        /* based on SCSI command group */
 619                 if ((opcode >= 0xc0) && old_hdr.twelve_byte)
 620                         cmd_size = 12;
 621         }
 622         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
 623                 "sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
 624 /* Determine buffer size.  */
 625         input_size = count - cmd_size;
 626         mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
 627         mxsize -= SZ_SG_HEADER;
 628         input_size -= SZ_SG_HEADER;
 629         if (input_size < 0) {
 630                 sg_remove_request(sfp, srp);
 631                 return -EIO;    /* User did not pass enough bytes for this command. */
 632         }
 633         hp = &srp->header;
 634         hp->interface_id = '\0';        /* indicator of old interface tunnelled */
 635         hp->cmd_len = (unsigned char) cmd_size;
 636         hp->iovec_count = 0;
 637         hp->mx_sb_len = 0;
 638         if (input_size > 0)
 639                 hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
 640                     SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
 641         else
 642                 hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
 643         hp->dxfer_len = mxsize;
 644         if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
 645             (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
 646                 hp->dxferp = (char __user *)buf + cmd_size;
 647         else
 648                 hp->dxferp = NULL;
 649         hp->sbp = NULL;
 650         hp->timeout = old_hdr.reply_len;        /* structure abuse ... */
 651         hp->flags = input_size; /* structure abuse ... */
 652         hp->pack_id = old_hdr.pack_id;
 653         hp->usr_ptr = NULL;
 654         if (__copy_from_user(cmnd, buf, cmd_size))
 655                 return -EFAULT;
 656         /*
 657          * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
 658          * but is is possible that the app intended SG_DXFER_TO_DEV, because there
 659          * is a non-zero input_size, so emit a warning.
 660          */
 661         if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
 662                 static char cmd[TASK_COMM_LEN];
 663                 if (strcmp(current->comm, cmd)) {
 664                         printk_ratelimited(KERN_WARNING
 665                                            "sg_write: data in/out %d/%d bytes "
 666                                            "for SCSI command 0x%x-- guessing "
 667                                            "data in;\n   program %s not setting "
 668                                            "count and/or reply_len properly\n",
 669                                            old_hdr.reply_len - (int)SZ_SG_HEADER,
 670                                            input_size, (unsigned int) cmnd[0],
 671                                            current->comm);
 672                         strcpy(cmd, current->comm);
 673                 }
 674         }
 675         k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
 676         return (k < 0) ? k : count;
 677 }
 678
 679 static ssize_t
 680 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 681                  size_t count, int blocking, int read_only, int sg_io_owned,
 682                  Sg_request **o_srp)
 683 {
 684         int k;
 685         Sg_request *srp;
 686         sg_io_hdr_t *hp;
 687         unsigned char cmnd[SG_MAX_CDB_SIZE];
 688         int timeout;
 689         unsigned long ul_timeout;
 690
 691         if (count < SZ_SG_IO_HDR)
 692                 return -EINVAL;
 693         if (!access_ok(VERIFY_READ, buf, count))
 694                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 695
 696         sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
 697         if (!(srp = sg_add_request(sfp))) {
 698                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 699                                               "sg_new_write: queue full\n"));
 700                 return -EDOM;
 701         }
 702         srp->sg_io_owned = sg_io_owned;
 703         hp = &srp->header;
 704         if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
 705                 sg_remove_request(sfp, srp);
 706                 return -EFAULT;
 707         }
 708         if (hp->interface_id != 'S') {
 709                 sg_remove_request(sfp, srp);
 710                 return -ENOSYS;
 711         }
 712         if (hp->flags & SG_FLAG_MMAP_IO) {
 713                 if (hp->dxfer_len > sfp->reserve.bufflen) {
 714                         sg_remove_request(sfp, srp);
 715                         return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
 716                 }
 717                 if (hp->flags & SG_FLAG_DIRECT_IO) {
 718                         sg_remove_request(sfp, srp);
 719                         return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
 720                 }
 721                 if (sg_res_in_use(sfp)) {
 722                         sg_remove_request(sfp, srp);
 723                         return -EBUSY;  /* reserve buffer already being used */
 724                 }
 725         }
 726         ul_timeout = msecs_to_jiffies(srp->header.timeout);
 727         timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
 728         if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
 729                 sg_remove_request(sfp, srp);
 730                 return -EMSGSIZE;
 731         }
 732         if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
 733                 sg_remove_request(sfp, srp);
 734                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 735         }
 736         if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 737                 sg_remove_request(sfp, srp);
 738                 return -EFAULT;
 739         }
 740         if (read_only && sg_allow_access(file, cmnd)) {
 741                 sg_remove_request(sfp, srp);
 742                 return -EPERM;
 743         }
 744         k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
 745         if (k < 0)
 746                 return k;
 747         if (o_srp)
 748                 *o_srp = srp;
 749         return count;
 750 }
 751
 752 static int
 753 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 754                 unsigned char *cmnd, int timeout, int blocking)
 755 {
 756         int k, at_head;
 757         Sg_device *sdp = sfp->parentdp;
 758         sg_io_hdr_t *hp = &srp->header;
 759
 760         srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
 761         hp->status = 0;
 762         hp->masked_status = 0;
 763         hp->msg_status = 0;
 764         hp->info = 0;
 765         hp->host_status = 0;
 766         hp->driver_status = 0;
 767         hp->resid = 0;
 768         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
 769                         "sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
 770                         (int) cmnd[0], (int) hp->cmd_len));
 771
 772         k = sg_start_req(srp, cmnd);
 773         if (k) {
 774                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 775                         "sg_common_write: start_req err=%d\n", k));
 776                 sg_finish_rem_req(srp);
 777                 return k;       /* probably out of space --> ENOMEM */
 778         }
 779         if (atomic_read(&sdp->detaching)) {
 780                 if (srp->bio) {
 781                         if (srp->rq->cmd != srp->rq->__cmd)
 782                                 kfree(srp->rq->cmd);
 783
 784                         blk_end_request_all(srp->rq, -EIO);
 785                         srp->rq = NULL;
 786                 }
 787
 788                 sg_finish_rem_req(srp);
 789                 return -ENODEV;
 790         }
 791
 792         hp->duration = jiffies_to_msecs(jiffies);
 793         if (hp->interface_id != '\0' && /* v3 (or later) interface */
 794             (SG_FLAG_Q_AT_TAIL & hp->flags))
 795                 at_head = 0;
 796         else
 797                 at_head = 1;
 798
 799         srp->rq->timeout = timeout;
 800         kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
 801         blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
 802                               srp->rq, at_head, sg_rq_end_io);
 803         return 0;
 804 }
 805
 806 static int srp_done(Sg_fd *sfp, Sg_request *srp)
 807 {
 808         unsigned long flags;
 809         int ret;
 810
 811         read_lock_irqsave(&sfp->rq_list_lock, flags);
 812         ret = srp->done;
 813         read_unlock_irqrestore(&sfp->rq_list_lock, flags);
 814         return ret;
 815 }
 816
 817 static int max_sectors_bytes(struct request_queue *q)
 818 {
 819         unsigned int max_sectors = queue_max_sectors(q);
 820
 821         max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
 822
 823         return max_sectors << 9;
 824 }
 825
 826 static long
 827 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
 828 {
 829         void __user *p = (void __user *)arg;
 830         int __user *ip = p;
 831         int result, val, read_only;
 832         Sg_device *sdp;
 833         Sg_fd *sfp;
 834         Sg_request *srp;
 835         unsigned long iflags;
 836
 837         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 838                 return -ENXIO;
 839
 840         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 841                                    "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
 842         read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
 843
 844         switch (cmd_in) {
 845         case SG_IO:
 846                 if (atomic_read(&sdp->detaching))
 847                         return -ENODEV;
 848                 if (!scsi_block_when_processing_errors(sdp->device))
 849                         return -ENXIO;
 850                 if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
 851                         return -EFAULT;
 852                 result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 853                                  1, read_only, 1, &srp);
 854                 if (result < 0)
 855                         return result;
 856                 result = wait_event_interruptible(sfp->read_wait,
 857                         (srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
 858                 if (atomic_read(&sdp->detaching))
 859                         return -ENODEV;
 860                 write_lock_irq(&sfp->rq_list_lock);
 861                 if (srp->done) {
 862                         srp->done = 2;
 863                         write_unlock_irq(&sfp->rq_list_lock);
 864                         result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
 865                         return (result < 0) ? result : 0;
 866                 }
 867                 srp->orphan = 1;
 868                 write_unlock_irq(&sfp->rq_list_lock);
 869                 return result;  /* -ERESTARTSYS because signal hit process */
 870         case SG_SET_TIMEOUT:
 871                 result = get_user(val, ip);
 872                 if (result)
 873                         return result;
 874                 if (val < 0)
 875                         return -EIO;
 876                 if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
 877                         val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
 878                                     INT_MAX);
 879                 sfp->timeout_user = val;
 880                 sfp->timeout = mult_frac(val, HZ, USER_HZ);
 881
 882                 return 0;
 883         case SG_GET_TIMEOUT:    /* N.B. User receives timeout as return value */
 884                                 /* strange ..., for backward compatibility */
 885                 return sfp->timeout_user;
 886         case SG_SET_FORCE_LOW_DMA:
 887                 result = get_user(val, ip);
 888                 if (result)
 889                         return result;
 890                 if (val) {
 891                         sfp->low_dma = 1;
 892                         if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
 893                                 val = (int) sfp->reserve.bufflen;
 894                                 sg_remove_scat(sfp, &sfp->reserve);
 895                                 sg_build_reserve(sfp, val);
 896                         }
 897                 } else {
 898                         if (atomic_read(&sdp->detaching))
 899                                 return -ENODEV;
 900                         sfp->low_dma = sdp->device->host->unchecked_isa_dma;
 901                 }
 902                 return 0;
 903         case SG_GET_LOW_DMA:
 904                 return put_user((int) sfp->low_dma, ip);
 905         case SG_GET_SCSI_ID:
 906                 if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
 907                         return -EFAULT;
 908                 else {
 909                         sg_scsi_id_t __user *sg_idp = p;
 910
 911                         if (atomic_read(&sdp->detaching))
 912                                 return -ENODEV;
 913                         __put_user((int) sdp->device->host->host_no,
 914                                    &sg_idp->host_no);
 915                         __put_user((int) sdp->device->channel,
 916                                    &sg_idp->channel);
 917                         __put_user((int) sdp->device->id, &sg_idp->scsi_id);
 918                         __put_user((int) sdp->device->lun, &sg_idp->lun);
 919                         __put_user((int) sdp->device->type, &sg_idp->scsi_type);
 920                         __put_user((short) sdp->device->host->cmd_per_lun,
 921                                    &sg_idp->h_cmd_per_lun);
 922                         __put_user((short) sdp->device->queue_depth,
 923                                    &sg_idp->d_queue_depth);
 924                         __put_user(0, &sg_idp->unused[0]);
 925                         __put_user(0, &sg_idp->unused[1]);
 926                         return 0;
 927                 }
 928         case SG_SET_FORCE_PACK_ID:
 929                 result = get_user(val, ip);
 930                 if (result)
 931                         return result;
 932                 sfp->force_packid = val ? 1 : 0;
 933                 return 0;
 934         case SG_GET_PACK_ID:
 935                 if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
 936                         return -EFAULT;
 937                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
 938                 for (srp = sfp->headrp; srp; srp = srp->nextrp) {
 939                         if ((1 == srp->done) && (!srp->sg_io_owned)) {
 940                                 read_unlock_irqrestore(&sfp->rq_list_lock,
 941                                                        iflags);
 942                                 __put_user(srp->header.pack_id, ip);
 943                                 return 0;
 944                         }
 945                 }
 946                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
 947                 __put_user(-1, ip);
 948                 return 0;
 949         case SG_GET_NUM_WAITING:
 950                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
 951                 for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
 952                         if ((1 == srp->done) && (!srp->sg_io_owned))
 953                                 ++val;
 954                 }
 955                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
 956                 return put_user(val, ip);
 957         case SG_GET_SG_TABLESIZE:
 958                 return put_user(sdp->sg_tablesize, ip);
 959         case SG_SET_RESERVED_SIZE:
 960                 result = get_user(val, ip);
 961                 if (result)
 962                         return result;
 963                 if (val < 0)
 964                         return -EINVAL;
 965                 val = min_t(int, val,
 966                             max_sectors_bytes(sdp->device->request_queue));
 967                 if (val != sfp->reserve.bufflen) {
 968                         if (sg_res_in_use(sfp) || sfp->mmap_called)
 969                                 return -EBUSY;
 970                         sg_remove_scat(sfp, &sfp->reserve);
 971                         sg_build_reserve(sfp, val);
 972                 }
 973                 return 0;
 974         case SG_GET_RESERVED_SIZE:
 975                 val = min_t(int, sfp->reserve.bufflen,
 976                             max_sectors_bytes(sdp->device->request_queue));
 977                 return put_user(val, ip);
 978         case SG_SET_COMMAND_Q:
 979                 result = get_user(val, ip);
 980                 if (result)
 981                         return result;
 982                 sfp->cmd_q = val ? 1 : 0;
 983                 return 0;
 984         case SG_GET_COMMAND_Q:
 985                 return put_user((int) sfp->cmd_q, ip);
 986         case SG_SET_KEEP_ORPHAN:
 987                 result = get_user(val, ip);
 988                 if (result)
 989                         return result;
 990                 sfp->keep_orphan = val;
 991                 return 0;
 992         case SG_GET_KEEP_ORPHAN:
 993                 return put_user((int) sfp->keep_orphan, ip);
 994         case SG_NEXT_CMD_LEN:
 995                 result = get_user(val, ip);
 996                 if (result)
 997                         return result;
 998                 sfp->next_cmd_len = (val > 0) ? val : 0;
 999                 return 0;
1000         case SG_GET_VERSION_NUM:
1001                 return put_user(sg_version_num, ip);
1002         case SG_GET_ACCESS_COUNT:
1003                 /* faked - we don't have a real access count anymore */
1004                 val = (sdp->device ? 1 : 0);
1005                 return put_user(val, ip);
1006         case SG_GET_REQUEST_TABLE:
1007                 if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
1008                         return -EFAULT;
1009                 else {
1010                         sg_req_info_t *rinfo;
1011                         unsigned int ms;
1012
1013                         rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
1014                                                                 GFP_KERNEL);
1015                         if (!rinfo)
1016                                 return -ENOMEM;
1017                         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1018                         for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
1019                              ++val, srp = srp ? srp->nextrp : srp) {
1020                                 memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
1021                                 if (srp) {
1022                                         rinfo[val].req_state = srp->done + 1;
1023                                         rinfo[val].problem =
1024                                             srp->header.masked_status &
1025                                             srp->header.host_status &
1026                                             srp->header.driver_status;
1027                                         if (srp->done)
1028                                                 rinfo[val].duration =
1029                                                         srp->header.duration;
1030                                         else {
1031                                                 ms = jiffies_to_msecs(jiffies);
1032                                                 rinfo[val].duration =
1033                                                     (ms > srp->header.duration) ?
1034                                                     (ms - srp->header.duration) : 0;
1035                                         }
1036                                         rinfo[val].orphan = srp->orphan;
1037                                         rinfo[val].sg_io_owned =
1038                                                         srp->sg_io_owned;
1039                                         rinfo[val].pack_id =
1040                                                         srp->header.pack_id;
1041                                         rinfo[val].usr_ptr =
1042                                                         srp->header.usr_ptr;
1043                                 }
1044                         }
1045                         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1046                         result = __copy_to_user(p, rinfo,
1047                                                 SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1048                         result = result ? -EFAULT : 0;
1049                         kfree(rinfo);
1050                         return result;
1051                 }
1052         case SG_EMULATED_HOST:
1053                 if (atomic_read(&sdp->detaching))
1054                         return -ENODEV;
1055                 return put_user(sdp->device->host->hostt->emulated, ip);
1056         case SCSI_IOCTL_SEND_COMMAND:
1057                 if (atomic_read(&sdp->detaching))
1058                         return -ENODEV;
1059                 if (read_only) {
1060                         unsigned char opcode = WRITE_6;
1061                         Scsi_Ioctl_Command __user *siocp = p;
1062
1063                         if (copy_from_user(&opcode, siocp->data, 1))
1064                                 return -EFAULT;
1065                         if (sg_allow_access(filp, &opcode))
1066                                 return -EPERM;
1067                 }
1068                 return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1069         case SG_SET_DEBUG:
1070                 result = get_user(val, ip);
1071                 if (result)
1072                         return result;
1073                 sdp->sgdebug = (char) val;
1074                 return 0;
1075         case BLKSECTGET:
1076                 return put_user(max_sectors_bytes(sdp->device->request_queue),
1077                                 ip);
1078         case BLKTRACESETUP:
1079                 return blk_trace_setup(sdp->device->request_queue,
1080                                        sdp->disk->disk_name,
1081                                        MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1082                                        NULL,
1083                                        (char *)arg);
1084         case BLKTRACESTART:
1085                 return blk_trace_startstop(sdp->device->request_queue, 1);
1086         case BLKTRACESTOP:
1087                 return blk_trace_startstop(sdp->device->request_queue, 0);
1088         case BLKTRACETEARDOWN:
1089                 return blk_trace_remove(sdp->device->request_queue);
1090         case SCSI_IOCTL_GET_IDLUN:
1091         case SCSI_IOCTL_GET_BUS_NUMBER:
1092         case SCSI_IOCTL_PROBE_HOST:
1093         case SG_GET_TRANSFORM:
1094         case SG_SCSI_RESET:
1095                 if (atomic_read(&sdp->detaching))
1096                         return -ENODEV;
1097                 break;
1098         default:
1099                 if (read_only)
1100                         return -EPERM;  /* don't know so take safe approach */
1101                 break;
1102         }
1103
1104         result = scsi_ioctl_block_when_processing_errors(sdp->device,
1105                         cmd_in, filp->f_flags & O_NDELAY);
1106         if (result)
1107                 return result;
1108         return scsi_ioctl(sdp->device, cmd_in, p);
1109 }
1110
1111 #ifdef CONFIG_COMPAT
1112 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1113 {
1114         Sg_device *sdp;
1115         Sg_fd *sfp;
1116         struct scsi_device *sdev;
1117
1118         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1119                 return -ENXIO;
1120
1121         sdev = sdp->device;
1122         if (sdev->host->hostt->compat_ioctl) {
1123                 int ret;
1124
1125                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1126
1127                 return ret;
1128         }
1129
1130         return -ENOIOCTLCMD;
1131 }
1132 #endif
1133
1134 static unsigned int
1135 sg_poll(struct file *filp, poll_table * wait)
1136 {
1137         unsigned int res = 0;
1138         Sg_device *sdp;
1139         Sg_fd *sfp;
1140         Sg_request *srp;
1141         int count = 0;
1142         unsigned long iflags;
1143
1144         sfp = filp->private_data;
1145         if (!sfp)
1146                 return POLLERR;
1147         sdp = sfp->parentdp;
1148         if (!sdp)
1149                 return POLLERR;
1150         poll_wait(filp, &sfp->read_wait, wait);
1151         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1152         for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1153                 /* if any read waiting, flag it */
1154                 if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1155                         res = POLLIN | POLLRDNORM;
1156                 ++count;
1157         }
1158         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1159
1160         if (atomic_read(&sdp->detaching))
1161                 res |= POLLHUP;
1162         else if (!sfp->cmd_q) {
1163                 if (0 == count)
1164                         res |= POLLOUT | POLLWRNORM;
1165         } else if (count < SG_MAX_QUEUE)
1166                 res |= POLLOUT | POLLWRNORM;
1167         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1168                                       "sg_poll: res=0x%x\n", (int) res));
1169         return res;
1170 }
1171
1172 static int
1173 sg_fasync(int fd, struct file *filp, int mode)
1174 {
1175         Sg_device *sdp;
1176         Sg_fd *sfp;
1177
1178         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1179                 return -ENXIO;
1180         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1181                                       "sg_fasync: mode=%d\n", mode));
1182
1183         return fasync_helper(fd, filp, mode, &sfp->async_qp);
1184 }
1185
1186 static int
1187 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1188 {
1189         Sg_fd *sfp;
1190         unsigned long offset, len, sa;
1191         Sg_scatter_hold *rsv_schp;
1192         int k, length;
1193
1194         if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1195                 return VM_FAULT_SIGBUS;
1196         rsv_schp = &sfp->reserve;
1197         offset = vmf->pgoff << PAGE_SHIFT;
1198         if (offset >= rsv_schp->bufflen)
1199                 return VM_FAULT_SIGBUS;
1200         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1201                                       "sg_vma_fault: offset=%lu, scatg=%d\n",
1202                                       offset, rsv_schp->k_use_sg));
1203         sa = vma->vm_start;
1204         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1205         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1206                 len = vma->vm_end - sa;
1207                 len = (len < length) ? len : length;
1208                 if (offset < len) {
1209                         struct page *page = nth_page(rsv_schp->pages[k],
1210                                                      offset >> PAGE_SHIFT);
1211                         get_page(page); /* increment page count */
1212                         vmf->page = page;
1213                         return 0; /* success */
1214                 }
1215                 sa += len;
1216                 offset -= len;
1217         }
1218
1219         return VM_FAULT_SIGBUS;
1220 }
1221
1222 static const struct vm_operations_struct sg_mmap_vm_ops = {
1223         .fault = sg_vma_fault,
1224 };
1225
1226 static int
1227 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1228 {
1229         Sg_fd *sfp;
1230         unsigned long req_sz, len, sa;
1231         Sg_scatter_hold *rsv_schp;
1232         int k, length;
1233
1234         if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1235                 return -ENXIO;
1236         req_sz = vma->vm_end - vma->vm_start;
1237         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1238                                       "sg_mmap starting, vm_start=%p, len=%d\n",
1239                                       (void *) vma->vm_start, (int) req_sz));
1240         if (vma->vm_pgoff)
1241                 return -EINVAL; /* want no offset */
1242         rsv_schp = &sfp->reserve;
1243         if (req_sz > rsv_schp->bufflen)
1244                 return -ENOMEM; /* cannot map more than reserved buffer */
1245
1246         sa = vma->vm_start;
1247         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1248         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1249                 len = vma->vm_end - sa;
1250                 len = (len < length) ? len : length;
1251                 sa += len;
1252         }
1253
1254         sfp->mmap_called = 1;
1255         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1256         vma->vm_private_data = sfp;
1257         vma->vm_ops = &sg_mmap_vm_ops;
1258         return 0;
1259 }
1260
1261 static void
1262 sg_rq_end_io_usercontext(struct work_struct *work)
1263 {
1264         struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1265         struct sg_fd *sfp = srp->parentfp;
1266
1267         sg_finish_rem_req(srp);
1268         kref_put(&sfp->f_ref, sg_remove_sfp);
1269 }
1270
1271 /*
1272  * This function is a "bottom half" handler that is called by the mid
1273  * level when a command is completed (or has failed).
1274  */
1275 static void
1276 sg_rq_end_io(struct request *rq, int uptodate)
1277 {
1278         struct sg_request *srp = rq->end_io_data;
1279         Sg_device *sdp;
1280         Sg_fd *sfp;
1281         unsigned long iflags;
1282         unsigned int ms;
1283         char *sense;
1284         int result, resid, done = 1;
1285
1286         if (WARN_ON(srp->done != 0))
1287                 return;
1288
1289         sfp = srp->parentfp;
1290         if (WARN_ON(sfp == NULL))
1291                 return;
1292
1293         sdp = sfp->parentdp;
1294         if (unlikely(atomic_read(&sdp->detaching)))
1295                 pr_info("%s: device detaching\n", __func__);
1296
1297         sense = rq->sense;
1298         result = rq->errors;
1299         resid = rq->resid_len;
1300
1301         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1302                                       "sg_cmd_done: pack_id=%d, res=0x%x\n",
1303                                       srp->header.pack_id, result));
1304         srp->header.resid = resid;
1305         ms = jiffies_to_msecs(jiffies);
1306         srp->header.duration = (ms > srp->header.duration) ?
1307                                 (ms - srp->header.duration) : 0;
1308         if (0 != result) {
1309                 struct scsi_sense_hdr sshdr;
1310
1311                 srp->header.status = 0xff & result;
1312                 srp->header.masked_status = status_byte(result);
1313                 srp->header.msg_status = msg_byte(result);
1314                 srp->header.host_status = host_byte(result);
1315                 srp->header.driver_status = driver_byte(result);
1316                 if ((sdp->sgdebug > 0) &&
1317                     ((CHECK_CONDITION == srp->header.masked_status) ||
1318                      (COMMAND_TERMINATED == srp->header.masked_status)))
1319                         __scsi_print_sense(sdp->device, __func__, sense,
1320                                            SCSI_SENSE_BUFFERSIZE);
1321
1322                 /* Following if statement is a patch supplied by Eric Youngdale */
1323                 if (driver_byte(result) != 0
1324                     && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1325                     && !scsi_sense_is_deferred(&sshdr)
1326                     && sshdr.sense_key == UNIT_ATTENTION
1327                     && sdp->device->removable) {
1328                         /* Detected possible disc change. Set the bit - this */
1329                         /* may be used if there are filesystems using this device */
1330                         sdp->device->changed = 1;
1331                 }
1332         }
1333         /* Rely on write phase to clean out srp status values, so no "else" */
1334
1335         /*
1336          * Free the request as soon as it is complete so that its resources
1337          * can be reused without waiting for userspace to read() the
1338          * result.  But keep the associated bio (if any) around until
1339          * blk_rq_unmap_user() can be called from user context.
1340          */
1341         srp->rq = NULL;
1342         if (rq->cmd != rq->__cmd)
1343                 kfree(rq->cmd);
1344         __blk_put_request(rq->q, rq);
1345
1346         write_lock_irqsave(&sfp->rq_list_lock, iflags);
1347         if (unlikely(srp->orphan)) {
1348                 if (sfp->keep_orphan)
1349                         srp->sg_io_owned = 0;
1350                 else
1351                         done = 0;
1352         }
1353         srp->done = done;
1354         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1355
1356         if (likely(done)) {
1357                 /* Now wake up any sg_read() that is waiting for this
1358                  * packet.
1359                  */
1360                 wake_up_interruptible(&sfp->read_wait);
1361                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1362                 kref_put(&sfp->f_ref, sg_remove_sfp);
1363         } else {
1364                 INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1365                 schedule_work(&srp->ew.work);
1366         }
1367 }
1368
1369 static const struct file_operations sg_fops = {
1370         .owner = THIS_MODULE,
1371         .read = sg_read,
1372         .write = sg_write,
1373         .poll = sg_poll,
1374         .unlocked_ioctl = sg_ioctl,
1375 #ifdef CONFIG_COMPAT
1376         .compat_ioctl = sg_compat_ioctl,
1377 #endif
1378         .open = sg_open,
1379         .mmap = sg_mmap,
1380         .release = sg_release,
1381         .fasync = sg_fasync,
1382         .llseek = no_llseek,
1383 };
1384
1385 static struct class *sg_sysfs_class;
1386
1387 static int sg_sysfs_valid = 0;
1388
1389 static Sg_device *
1390 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1391 {
1392         struct request_queue *q = scsidp->request_queue;
1393         Sg_device *sdp;
1394         unsigned long iflags;
1395         int error;
1396         u32 k;
1397
1398         sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1399         if (!sdp) {
1400                 sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1401                             "failure\n", __func__);
1402                 return ERR_PTR(-ENOMEM);
1403         }
1404
1405         idr_preload(GFP_KERNEL);
1406         write_lock_irqsave(&sg_index_lock, iflags);
1407
1408         error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1409         if (error < 0) {
1410                 if (error == -ENOSPC) {
1411                         sdev_printk(KERN_WARNING, scsidp,
1412                                     "Unable to attach sg device type=%d, minor number exceeds %d\n",
1413                                     scsidp->type, SG_MAX_DEVS - 1);
1414                         error = -ENODEV;
1415                 } else {
1416                         sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1417                                     "allocation Sg_device failure: %d\n",
1418                                     __func__, error);
1419                 }
1420                 goto out_unlock;
1421         }
1422         k = error;
1423
1424         SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1425                                         "sg_alloc: dev=%d \n", k));
1426         sprintf(disk->disk_name, "sg%d", k);
1427         disk->first_minor = k;
1428         sdp->disk = disk;
1429         sdp->device = scsidp;
1430         mutex_init(&sdp->open_rel_lock);
1431         INIT_LIST_HEAD(&sdp->sfds);
1432         init_waitqueue_head(&sdp->open_wait);
1433         atomic_set(&sdp->detaching, 0);
1434         rwlock_init(&sdp->sfd_lock);
1435         sdp->sg_tablesize = queue_max_segments(q);
1436         sdp->index = k;
1437         kref_init(&sdp->d_ref);
1438         error = 0;
1439
1440 out_unlock:
1441         write_unlock_irqrestore(&sg_index_lock, iflags);
1442         idr_preload_end();
1443
1444         if (error) {
1445                 kfree(sdp);
1446                 return ERR_PTR(error);
1447         }
1448         return sdp;
1449 }
1450
1451 static int
1452 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1453 {
1454         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1455         struct gendisk *disk;
1456         Sg_device *sdp = NULL;
1457         struct cdev * cdev = NULL;
1458         int error;
1459         unsigned long iflags;
1460
1461         disk = alloc_disk(1);
1462         if (!disk) {
1463                 pr_warn("%s: alloc_disk failed\n", __func__);
1464                 return -ENOMEM;
1465         }
1466         disk->major = SCSI_GENERIC_MAJOR;
1467
1468         error = -ENOMEM;
1469         cdev = cdev_alloc();
1470         if (!cdev) {
1471                 pr_warn("%s: cdev_alloc failed\n", __func__);
1472                 goto out;
1473         }
1474         cdev->owner = THIS_MODULE;
1475         cdev->ops = &sg_fops;
1476
1477         sdp = sg_alloc(disk, scsidp);
1478         if (IS_ERR(sdp)) {
1479                 pr_warn("%s: sg_alloc failed\n", __func__);
1480                 error = PTR_ERR(sdp);
1481                 goto out;
1482         }
1483
1484         error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1485         if (error)
1486                 goto cdev_add_err;
1487
1488         sdp->cdev = cdev;
1489         if (sg_sysfs_valid) {
1490                 struct device *sg_class_member;
1491
1492                 sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1493                                                 MKDEV(SCSI_GENERIC_MAJOR,
1494                                                       sdp->index),
1495                                                 sdp, "%s", disk->disk_name);
1496                 if (IS_ERR(sg_class_member)) {
1497                         pr_err("%s: device_create failed\n", __func__);
1498                         error = PTR_ERR(sg_class_member);
1499                         goto cdev_add_err;
1500                 }
1501                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1502                                           &sg_class_member->kobj, "generic");
1503                 if (error)
1504                         pr_err("%s: unable to make symlink 'generic' back "
1505                                "to sg%d\n", __func__, sdp->index);
1506         } else
1507                 pr_warn("%s: sg_sys Invalid\n", __func__);
1508
1509         sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1510                     "type %d\n", sdp->index, scsidp->type);
1511
1512         dev_set_drvdata(cl_dev, sdp);
1513
1514         return 0;
1515
1516 cdev_add_err:
1517         write_lock_irqsave(&sg_index_lock, iflags);
1518         idr_remove(&sg_index_idr, sdp->index);
1519         write_unlock_irqrestore(&sg_index_lock, iflags);
1520         kfree(sdp);
1521
1522 out:
1523         put_disk(disk);
1524         if (cdev)
1525                 cdev_del(cdev);
1526         return error;
1527 }
1528
1529 static void
1530 sg_device_destroy(struct kref *kref)
1531 {
1532         struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1533         unsigned long flags;
1534
1535         /* CAUTION!  Note that the device can still be found via idr_find()
1536          * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1537          * any other cleanup.
1538          */
1539
1540         write_lock_irqsave(&sg_index_lock, flags);
1541         idr_remove(&sg_index_idr, sdp->index);
1542         write_unlock_irqrestore(&sg_index_lock, flags);
1543
1544         SCSI_LOG_TIMEOUT(3,
1545                 sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1546
1547         put_disk(sdp->disk);
1548         kfree(sdp);
1549 }
1550
1551 static void
1552 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1553 {
1554         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1555         Sg_device *sdp = dev_get_drvdata(cl_dev);
1556         unsigned long iflags;
1557         Sg_fd *sfp;
1558         int val;
1559
1560         if (!sdp)
1561                 return;
1562         /* want sdp->detaching non-zero as soon as possible */
1563         val = atomic_inc_return(&sdp->detaching);
1564         if (val > 1)
1565                 return; /* only want to do following once per device */
1566
1567         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1568                                       "%s\n", __func__));
1569
1570         read_lock_irqsave(&sdp->sfd_lock, iflags);
1571         list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1572                 wake_up_interruptible_all(&sfp->read_wait);
1573                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1574         }
1575         wake_up_interruptible_all(&sdp->open_wait);
1576         read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1577
1578         sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1579         device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1580         cdev_del(sdp->cdev);
1581         sdp->cdev = NULL;
1582
1583         kref_put(&sdp->d_ref, sg_device_destroy);
1584 }
1585
1586 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1587 module_param_named(def_reserved_size, def_reserved_size, int,
1588                    S_IRUGO | S_IWUSR);
1589 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1590
1591 MODULE_AUTHOR("Douglas Gilbert");
1592 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1593 MODULE_LICENSE("GPL");
1594 MODULE_VERSION(SG_VERSION_STR);
1595 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1596
1597 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1598                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1599 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1600 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1601
1602 static int __init
1603 init_sg(void)
1604 {
1605         int rc;
1606
1607         if (scatter_elem_sz < PAGE_SIZE) {
1608                 scatter_elem_sz = PAGE_SIZE;
1609                 scatter_elem_sz_prev = scatter_elem_sz;
1610         }
1611         if (def_reserved_size >= 0)
1612                 sg_big_buff = def_reserved_size;
1613         else
1614                 def_reserved_size = sg_big_buff;
1615
1616         rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1617                                     SG_MAX_DEVS, "sg");
1618         if (rc)
1619                 return rc;
1620         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1621         if ( IS_ERR(sg_sysfs_class) ) {
1622                 rc = PTR_ERR(sg_sysfs_class);
1623                 goto err_out;
1624         }
1625         sg_sysfs_valid = 1;
1626         rc = scsi_register_interface(&sg_interface);
1627         if (0 == rc) {
1628 #ifdef CONFIG_SCSI_PROC_FS
1629                 sg_proc_init();
1630 #endif                          /* CONFIG_SCSI_PROC_FS */
1631                 return 0;
1632         }
1633         class_destroy(sg_sysfs_class);
1634 err_out:
1635         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1636         return rc;
1637 }
1638
1639 static void __exit
1640 exit_sg(void)
1641 {
1642 #ifdef CONFIG_SCSI_PROC_FS
1643         sg_proc_cleanup();
1644 #endif                          /* CONFIG_SCSI_PROC_FS */
1645         scsi_unregister_interface(&sg_interface);
1646         class_destroy(sg_sysfs_class);
1647         sg_sysfs_valid = 0;
1648         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1649                                  SG_MAX_DEVS);
1650         idr_destroy(&sg_index_idr);
1651 }
1652
1653 static int
1654 sg_start_req(Sg_request *srp, unsigned char *cmd)
1655 {
1656         int res;
1657         struct request *rq;
1658         Sg_fd *sfp = srp->parentfp;
1659         sg_io_hdr_t *hp = &srp->header;
1660         int dxfer_len = (int) hp->dxfer_len;
1661         int dxfer_dir = hp->dxfer_direction;
1662         unsigned int iov_count = hp->iovec_count;
1663         Sg_scatter_hold *req_schp = &srp->data;
1664         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1665         struct request_queue *q = sfp->parentdp->device->request_queue;
1666         struct rq_map_data *md, map_data;
1667         int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1668         unsigned char *long_cmdp = NULL;
1669
1670         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1671                                       "sg_start_req: dxfer_len=%d\n",
1672                                       dxfer_len));
1673
1674         if (hp->cmd_len > BLK_MAX_CDB) {
1675                 long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1676                 if (!long_cmdp)
1677                         return -ENOMEM;
1678         }
1679
1680         /*
1681          * NOTE
1682          *
1683          * With scsi-mq enabled, there are a fixed number of preallocated
1684          * requests equal in number to shost->can_queue.  If all of the
1685          * preallocated requests are already in use, then using GFP_ATOMIC with
1686          * blk_get_request() will return -EWOULDBLOCK, whereas using GFP_KERNEL
1687          * will cause blk_get_request() to sleep until an active command
1688          * completes, freeing up a request.  Neither option is ideal, but
1689          * GFP_KERNEL is the better choice to prevent userspace from getting an
1690          * unexpected EWOULDBLOCK.
1691          *
1692          * With scsi-mq disabled, blk_get_request() with GFP_KERNEL usually
1693          * does not sleep except under memory pressure.
1694          */
1695         rq = blk_get_request(q, rw, GFP_KERNEL);
1696         if (IS_ERR(rq)) {
1697                 kfree(long_cmdp);
1698                 return PTR_ERR(rq);
1699         }
1700
1701         blk_rq_set_block_pc(rq);
1702
1703         if (hp->cmd_len > BLK_MAX_CDB)
1704                 rq->cmd = long_cmdp;
1705         memcpy(rq->cmd, cmd, hp->cmd_len);
1706         rq->cmd_len = hp->cmd_len;
1707
1708         srp->rq = rq;
1709         rq->end_io_data = srp;
1710         rq->sense = srp->sense_b;
1711         rq->retries = SG_DEFAULT_RETRIES;
1712
1713         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1714                 return 0;
1715
1716         if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1717             dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1718             !sfp->parentdp->device->host->unchecked_isa_dma &&
1719             blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1720                 md = NULL;
1721         else
1722                 md = &map_data;
1723
1724         if (md) {
1725                 if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1726                         sg_link_reserve(sfp, srp, dxfer_len);
1727                 else {
1728                         res = sg_build_indirect(req_schp, sfp, dxfer_len);
1729                         if (res)
1730                                 return res;
1731                 }
1732
1733                 md->pages = req_schp->pages;
1734                 md->page_order = req_schp->page_order;
1735                 md->nr_entries = req_schp->k_use_sg;
1736                 md->offset = 0;
1737                 md->null_mapped = hp->dxferp ? 0 : 1;
1738                 if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1739                         md->from_user = 1;
1740                 else
1741                         md->from_user = 0;
1742         }
1743
1744         if (iov_count) {
1745                 struct iovec *iov = NULL;
1746                 struct iov_iter i;
1747
1748                 res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
1749                 if (res < 0)
1750                         return res;
1751
1752                 iov_iter_truncate(&i, hp->dxfer_len);
1753
1754                 res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1755                 kfree(iov);
1756         } else
1757                 res = blk_rq_map_user(q, rq, md, hp->dxferp,
1758                                       hp->dxfer_len, GFP_ATOMIC);
1759
1760         if (!res) {
1761                 srp->bio = rq->bio;
1762
1763                 if (!md) {
1764                         req_schp->dio_in_use = 1;
1765                         hp->info |= SG_INFO_DIRECT_IO;
1766                 }
1767         }
1768         return res;
1769 }
1770
1771 static int
1772 sg_finish_rem_req(Sg_request *srp)
1773 {
1774         int ret = 0;
1775
1776         Sg_fd *sfp = srp->parentfp;
1777         Sg_scatter_hold *req_schp = &srp->data;
1778
1779         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1780                                       "sg_finish_rem_req: res_used=%d\n",
1781                                       (int) srp->res_used));
1782         if (srp->bio)
1783                 ret = blk_rq_unmap_user(srp->bio);
1784
1785         if (srp->rq) {
1786                 if (srp->rq->cmd != srp->rq->__cmd)
1787                         kfree(srp->rq->cmd);
1788                 blk_put_request(srp->rq);
1789         }
1790
1791         if (srp->res_used)
1792                 sg_unlink_reserve(sfp, srp);
1793         else
1794                 sg_remove_scat(sfp, req_schp);
1795
1796         sg_remove_request(sfp, srp);
1797
1798         return ret;
1799 }
1800
1801 static int
1802 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1803 {
1804         int sg_bufflen = tablesize * sizeof(struct page *);
1805         gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1806
1807         schp->pages = kzalloc(sg_bufflen, gfp_flags);
1808         if (!schp->pages)
1809                 return -ENOMEM;
1810         schp->sglist_len = sg_bufflen;
1811         return tablesize;       /* number of scat_gath elements allocated */
1812 }
1813
1814 static int
1815 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1816 {
1817         int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1818         int sg_tablesize = sfp->parentdp->sg_tablesize;
1819         int blk_size = buff_size, order;
1820         gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1821
1822         if (blk_size < 0)
1823                 return -EFAULT;
1824         if (0 == blk_size)
1825                 ++blk_size;     /* don't know why */
1826         /* round request up to next highest SG_SECTOR_SZ byte boundary */
1827         blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1828         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1829                 "sg_build_indirect: buff_size=%d, blk_size=%d\n",
1830                 buff_size, blk_size));
1831
1832         /* N.B. ret_sz carried into this block ... */
1833         mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1834         if (mx_sc_elems < 0)
1835                 return mx_sc_elems;     /* most likely -ENOMEM */
1836
1837         num = scatter_elem_sz;
1838         if (unlikely(num != scatter_elem_sz_prev)) {
1839                 if (num < PAGE_SIZE) {
1840                         scatter_elem_sz = PAGE_SIZE;
1841                         scatter_elem_sz_prev = PAGE_SIZE;
1842                 } else
1843                         scatter_elem_sz_prev = num;
1844         }
1845
1846         if (sfp->low_dma)
1847                 gfp_mask |= GFP_DMA;
1848
1849         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1850                 gfp_mask |= __GFP_ZERO;
1851
1852         order = get_order(num);
1853 retry:
1854         ret_sz = 1 << (PAGE_SHIFT + order);
1855
1856         for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1857              k++, rem_sz -= ret_sz) {
1858
1859                 num = (rem_sz > scatter_elem_sz_prev) ?
1860                         scatter_elem_sz_prev : rem_sz;
1861
1862                 schp->pages[k] = alloc_pages(gfp_mask, order);
1863                 if (!schp->pages[k])
1864                         goto out;
1865
1866                 if (num == scatter_elem_sz_prev) {
1867                         if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1868                                 scatter_elem_sz = ret_sz;
1869                                 scatter_elem_sz_prev = ret_sz;
1870                         }
1871                 }
1872
1873                 SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1874                                  "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1875                                  k, num, ret_sz));
1876         }               /* end of for loop */
1877
1878         schp->page_order = order;
1879         schp->k_use_sg = k;
1880         SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1881                          "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1882                          k, rem_sz));
1883
1884         schp->bufflen = blk_size;
1885         if (rem_sz > 0) /* must have failed */
1886                 return -ENOMEM;
1887         return 0;
1888 out:
1889         for (i = 0; i < k; i++)
1890                 __free_pages(schp->pages[i], order);
1891
1892         if (--order >= 0)
1893                 goto retry;
1894
1895         return -ENOMEM;
1896 }
1897
1898 static void
1899 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1900 {
1901         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1902                          "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1903         if (schp->pages && schp->sglist_len > 0) {
1904                 if (!schp->dio_in_use) {
1905                         int k;
1906
1907                         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1908                                 SCSI_LOG_TIMEOUT(5,
1909                                         sg_printk(KERN_INFO, sfp->parentdp,
1910                                         "sg_remove_scat: k=%d, pg=0x%p\n",
1911                                         k, schp->pages[k]));
1912                                 __free_pages(schp->pages[k], schp->page_order);
1913                         }
1914
1915                         kfree(schp->pages);
1916                 }
1917         }
1918         memset(schp, 0, sizeof (*schp));
1919 }
1920
1921 static int
1922 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1923 {
1924         Sg_scatter_hold *schp = &srp->data;
1925         int k, num;
1926
1927         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1928                          "sg_read_oxfer: num_read_xfer=%d\n",
1929                          num_read_xfer));
1930         if ((!outp) || (num_read_xfer <= 0))
1931                 return 0;
1932
1933         num = 1 << (PAGE_SHIFT + schp->page_order);
1934         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1935                 if (num > num_read_xfer) {
1936                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1937                                            num_read_xfer))
1938                                 return -EFAULT;
1939                         break;
1940                 } else {
1941                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1942                                            num))
1943                                 return -EFAULT;
1944                         num_read_xfer -= num;
1945                         if (num_read_xfer <= 0)
1946                                 break;
1947                         outp += num;
1948                 }
1949         }
1950
1951         return 0;
1952 }
1953
1954 static void
1955 sg_build_reserve(Sg_fd * sfp, int req_size)
1956 {
1957         Sg_scatter_hold *schp = &sfp->reserve;
1958
1959         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1960                          "sg_build_reserve: req_size=%d\n", req_size));
1961         do {
1962                 if (req_size < PAGE_SIZE)
1963                         req_size = PAGE_SIZE;
1964                 if (0 == sg_build_indirect(schp, sfp, req_size))
1965                         return;
1966                 else
1967                         sg_remove_scat(sfp, schp);
1968                 req_size >>= 1; /* divide by 2 */
1969         } while (req_size > (PAGE_SIZE / 2));
1970 }
1971
1972 static void
1973 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1974 {
1975         Sg_scatter_hold *req_schp = &srp->data;
1976         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1977         int k, num, rem;
1978
1979         srp->res_used = 1;
1980         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1981                          "sg_link_reserve: size=%d\n", size));
1982         rem = size;
1983
1984         num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1985         for (k = 0; k < rsv_schp->k_use_sg; k++) {
1986                 if (rem <= num) {
1987                         req_schp->k_use_sg = k + 1;
1988                         req_schp->sglist_len = rsv_schp->sglist_len;
1989                         req_schp->pages = rsv_schp->pages;
1990
1991                         req_schp->bufflen = size;
1992                         req_schp->page_order = rsv_schp->page_order;
1993                         break;
1994                 } else
1995                         rem -= num;
1996         }
1997
1998         if (k >= rsv_schp->k_use_sg)
1999                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2000                                  "sg_link_reserve: BAD size\n"));
2001 }
2002
2003 static void
2004 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2005 {
2006         Sg_scatter_hold *req_schp = &srp->data;
2007
2008         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2009                                       "sg_unlink_reserve: req->k_use_sg=%d\n",
2010                                       (int) req_schp->k_use_sg));
2011         req_schp->k_use_sg = 0;
2012         req_schp->bufflen = 0;
2013         req_schp->pages = NULL;
2014         req_schp->page_order = 0;
2015         req_schp->sglist_len = 0;
2016         sfp->save_scat_len = 0;
2017         srp->res_used = 0;
2018 }
2019
2020 static Sg_request *
2021 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2022 {
2023         Sg_request *resp;
2024         unsigned long iflags;
2025
2026         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2027         for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2028                 /* look for requests that are ready + not SG_IO owned */
2029                 if ((1 == resp->done) && (!resp->sg_io_owned) &&
2030                     ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2031                         resp->done = 2; /* guard against other readers */
2032                         break;
2033                 }
2034         }
2035         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2036         return resp;
2037 }
2038
2039 /* always adds to end of list */
2040 static Sg_request *
2041 sg_add_request(Sg_fd * sfp)
2042 {
2043         int k;
2044         unsigned long iflags;
2045         Sg_request *resp;
2046         Sg_request *rp = sfp->req_arr;
2047
2048         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2049         resp = sfp->headrp;
2050         if (!resp) {
2051                 memset(rp, 0, sizeof (Sg_request));
2052                 rp->parentfp = sfp;
2053                 resp = rp;
2054                 sfp->headrp = resp;
2055         } else {
2056                 if (0 == sfp->cmd_q)
2057                         resp = NULL;    /* command queuing disallowed */
2058                 else {
2059                         for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2060                                 if (!rp->parentfp)
2061                                         break;
2062                         }
2063                         if (k < SG_MAX_QUEUE) {
2064                                 memset(rp, 0, sizeof (Sg_request));
2065                                 rp->parentfp = sfp;
2066                                 while (resp->nextrp)
2067                                         resp = resp->nextrp;
2068                                 resp->nextrp = rp;
2069                                 resp = rp;
2070                         } else
2071                                 resp = NULL;
2072                 }
2073         }
2074         if (resp) {
2075                 resp->nextrp = NULL;
2076                 resp->header.duration = jiffies_to_msecs(jiffies);
2077         }
2078         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2079         return resp;
2080 }
2081
2082 /* Return of 1 for found; 0 for not found */
2083 static int
2084 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2085 {
2086         Sg_request *prev_rp;
2087         Sg_request *rp;
2088         unsigned long iflags;
2089         int res = 0;
2090
2091         if ((!sfp) || (!srp) || (!sfp->headrp))
2092                 return res;
2093         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2094         prev_rp = sfp->headrp;
2095         if (srp == prev_rp) {
2096                 sfp->headrp = prev_rp->nextrp;
2097                 prev_rp->parentfp = NULL;
2098                 res = 1;
2099         } else {
2100                 while ((rp = prev_rp->nextrp)) {
2101                         if (srp == rp) {
2102                                 prev_rp->nextrp = rp->nextrp;
2103                                 rp->parentfp = NULL;
2104                                 res = 1;
2105                                 break;
2106                         }
2107                         prev_rp = rp;
2108                 }
2109         }
2110         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2111         return res;
2112 }
2113
2114 static Sg_fd *
2115 sg_add_sfp(Sg_device * sdp)
2116 {
2117         Sg_fd *sfp;
2118         unsigned long iflags;
2119         int bufflen;
2120
2121         sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2122         if (!sfp)
2123                 return ERR_PTR(-ENOMEM);
2124
2125         init_waitqueue_head(&sfp->read_wait);
2126         rwlock_init(&sfp->rq_list_lock);
2127
2128         kref_init(&sfp->f_ref);
2129         sfp->timeout = SG_DEFAULT_TIMEOUT;
2130         sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2131         sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2132         sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2133             sdp->device->host->unchecked_isa_dma : 1;
2134         sfp->cmd_q = SG_DEF_COMMAND_Q;
2135         sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2136         sfp->parentdp = sdp;
2137         write_lock_irqsave(&sdp->sfd_lock, iflags);
2138         if (atomic_read(&sdp->detaching)) {
2139                 write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2140                 return ERR_PTR(-ENODEV);
2141         }
2142         list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2143         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2144         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2145                                       "sg_add_sfp: sfp=0x%p\n", sfp));
2146         if (unlikely(sg_big_buff != def_reserved_size))
2147                 sg_big_buff = def_reserved_size;
2148
2149         bufflen = min_t(int, sg_big_buff,
2150                         max_sectors_bytes(sdp->device->request_queue));
2151         sg_build_reserve(sfp, bufflen);
2152         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2153                                       "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2154                                       sfp->reserve.bufflen,
2155                                       sfp->reserve.k_use_sg));
2156
2157         kref_get(&sdp->d_ref);
2158         __module_get(THIS_MODULE);
2159         return sfp;
2160 }
2161
2162 static void
2163 sg_remove_sfp_usercontext(struct work_struct *work)
2164 {
2165         struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2166         struct sg_device *sdp = sfp->parentdp;
2167
2168         /* Cleanup any responses which were never read(). */
2169         while (sfp->headrp)
2170                 sg_finish_rem_req(sfp->headrp);
2171
2172         if (sfp->reserve.bufflen > 0) {
2173                 SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2174                                 "sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2175                                 (int) sfp->reserve.bufflen,
2176                                 (int) sfp->reserve.k_use_sg));
2177                 sg_remove_scat(sfp, &sfp->reserve);
2178         }
2179
2180         SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2181                         "sg_remove_sfp: sfp=0x%p\n", sfp));
2182         kfree(sfp);
2183
2184         scsi_device_put(sdp->device);
2185         kref_put(&sdp->d_ref, sg_device_destroy);
2186         module_put(THIS_MODULE);
2187 }
2188
2189 static void
2190 sg_remove_sfp(struct kref *kref)
2191 {
2192         struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2193         struct sg_device *sdp = sfp->parentdp;
2194         unsigned long iflags;
2195
2196         write_lock_irqsave(&sdp->sfd_lock, iflags);
2197         list_del(&sfp->sfd_siblings);
2198         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2199
2200         INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2201         schedule_work(&sfp->ew.work);
2202 }
2203
2204 static int
2205 sg_res_in_use(Sg_fd * sfp)
2206 {
2207         const Sg_request *srp;
2208         unsigned long iflags;
2209
2210         read_lock_irqsave(&sfp->rq_list_lock, iflags);
2211         for (srp = sfp->headrp; srp; srp = srp->nextrp)
2212                 if (srp->res_used)
2213                         break;
2214         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2215         return srp ? 1 : 0;
2216 }
2217
2218 #ifdef CONFIG_SCSI_PROC_FS
2219 static int
2220 sg_idr_max_id(int id, void *p, void *data)
2221 {
2222         int *k = data;
2223
2224         if (*k < id)
2225                 *k = id;
2226
2227         return 0;
2228 }
2229
2230 static int
2231 sg_last_dev(void)
2232 {
2233         int k = -1;
2234         unsigned long iflags;
2235
2236         read_lock_irqsave(&sg_index_lock, iflags);
2237         idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2238         read_unlock_irqrestore(&sg_index_lock, iflags);
2239         return k + 1;           /* origin 1 */
2240 }
2241 #endif
2242
2243 /* must be called with sg_index_lock held */
2244 static Sg_device *sg_lookup_dev(int dev)
2245 {
2246         return idr_find(&sg_index_idr, dev);
2247 }
2248
2249 static Sg_device *
2250 sg_get_dev(int dev)
2251 {
2252         struct sg_device *sdp;
2253         unsigned long flags;
2254
2255         read_lock_irqsave(&sg_index_lock, flags);
2256         sdp = sg_lookup_dev(dev);
2257         if (!sdp)
2258                 sdp = ERR_PTR(-ENXIO);
2259         else if (atomic_read(&sdp->detaching)) {
2260                 /* If sdp->detaching, then the refcount may already be 0, in
2261                  * which case it would be a bug to do kref_get().
2262                  */
2263                 sdp = ERR_PTR(-ENODEV);
2264         } else
2265                 kref_get(&sdp->d_ref);
2266         read_unlock_irqrestore(&sg_index_lock, flags);
2267
2268         return sdp;
2269 }
2270
2271 #ifdef CONFIG_SCSI_PROC_FS
2272
2273 static struct proc_dir_entry *sg_proc_sgp = NULL;
2274
2275 static char sg_proc_sg_dirname[] = "scsi/sg";
2276
2277 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2278
2279 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2280 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2281                                   size_t count, loff_t *off);
2282 static const struct file_operations adio_fops = {
2283         .owner = THIS_MODULE,
2284         .open = sg_proc_single_open_adio,
2285         .read = seq_read,
2286         .llseek = seq_lseek,
2287         .write = sg_proc_write_adio,
2288         .release = single_release,
2289 };
2290
2291 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2292 static ssize_t sg_proc_write_dressz(struct file *filp,
2293                 const char __user *buffer, size_t count, loff_t *off);
2294 static const struct file_operations dressz_fops = {
2295         .owner = THIS_MODULE,
2296         .open = sg_proc_single_open_dressz,
2297         .read = seq_read,
2298         .llseek = seq_lseek,
2299         .write = sg_proc_write_dressz,
2300         .release = single_release,
2301 };
2302
2303 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2304 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2305 static const struct file_operations version_fops = {
2306         .owner = THIS_MODULE,
2307         .open = sg_proc_single_open_version,
2308         .read = seq_read,
2309         .llseek = seq_lseek,
2310         .release = single_release,
2311 };
2312
2313 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2314 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2315 static const struct file_operations devhdr_fops = {
2316         .owner = THIS_MODULE,
2317         .open = sg_proc_single_open_devhdr,
2318         .read = seq_read,
2319         .llseek = seq_lseek,
2320         .release = single_release,
2321 };
2322
2323 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2324 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2325 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2326 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2327 static void dev_seq_stop(struct seq_file *s, void *v);
2328 static const struct file_operations dev_fops = {
2329         .owner = THIS_MODULE,
2330         .open = sg_proc_open_dev,
2331         .read = seq_read,
2332         .llseek = seq_lseek,
2333         .release = seq_release,
2334 };
2335 static const struct seq_operations dev_seq_ops = {
2336         .start = dev_seq_start,
2337         .next  = dev_seq_next,
2338         .stop  = dev_seq_stop,
2339         .show  = sg_proc_seq_show_dev,
2340 };
2341
2342 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2343 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2344 static const struct file_operations devstrs_fops = {
2345         .owner = THIS_MODULE,
2346         .open = sg_proc_open_devstrs,
2347         .read = seq_read,
2348         .llseek = seq_lseek,
2349         .release = seq_release,
2350 };
2351 static const struct seq_operations devstrs_seq_ops = {
2352         .start = dev_seq_start,
2353         .next  = dev_seq_next,
2354         .stop  = dev_seq_stop,
2355         .show  = sg_proc_seq_show_devstrs,
2356 };
2357
2358 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2359 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2360 static const struct file_operations debug_fops = {
2361         .owner = THIS_MODULE,
2362         .open = sg_proc_open_debug,
2363         .read = seq_read,
2364         .llseek = seq_lseek,
2365         .release = seq_release,
2366 };
2367 static const struct seq_operations debug_seq_ops = {
2368         .start = dev_seq_start,
2369         .next  = dev_seq_next,
2370         .stop  = dev_seq_stop,
2371         .show  = sg_proc_seq_show_debug,
2372 };
2373
2374
2375 struct sg_proc_leaf {
2376         const char * name;
2377         const struct file_operations * fops;
2378 };
2379
2380 static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
2381         {"allow_dio", &adio_fops},
2382         {"debug", &debug_fops},
2383         {"def_reserved_size", &dressz_fops},
2384         {"device_hdr", &devhdr_fops},
2385         {"devices", &dev_fops},
2386         {"device_strs", &devstrs_fops},
2387         {"version", &version_fops}
2388 };
2389
2390 static int
2391 sg_proc_init(void)
2392 {
2393         int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2394         int k;
2395
2396         sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2397         if (!sg_proc_sgp)
2398                 return 1;
2399         for (k = 0; k < num_leaves; ++k) {
2400                 const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2401                 umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2402                 proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2403         }
2404         return 0;
2405 }
2406
2407 static void
2408 sg_proc_cleanup(void)
2409 {
2410         int k;
2411         int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2412
2413         if (!sg_proc_sgp)
2414                 return;
2415         for (k = 0; k < num_leaves; ++k)
2416                 remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2417         remove_proc_entry(sg_proc_sg_dirname, NULL);
2418 }
2419
2420
2421 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2422 {
2423         seq_printf(s, "%d\n", *((int *)s->private));
2424         return 0;
2425 }
2426
2427 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2428 {
2429         return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2430 }
2431
2432 static ssize_t
2433 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2434                    size_t count, loff_t *off)
2435 {
2436         int err;
2437         unsigned long num;
2438
2439         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2440                 return -EACCES;
2441         err = kstrtoul_from_user(buffer, count, 0, &num);
2442         if (err)
2443                 return err;
2444         sg_allow_dio = num ? 1 : 0;
2445         return count;
2446 }
2447
2448 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2449 {
2450         return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2451 }
2452
2453 static ssize_t
2454 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2455                      size_t count, loff_t *off)
2456 {
2457         int err;
2458         unsigned long k = ULONG_MAX;
2459
2460         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2461                 return -EACCES;
2462
2463         err = kstrtoul_from_user(buffer, count, 0, &k);
2464         if (err)
2465                 return err;
2466         if (k <= 1048576) {     /* limit "big buff" to 1 MB */
2467                 sg_big_buff = k;
2468                 return count;
2469         }
2470         return -ERANGE;
2471 }
2472
2473 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2474 {
2475         seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2476                    sg_version_date);
2477         return 0;
2478 }
2479
2480 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2481 {
2482         return single_open(file, sg_proc_seq_show_version, NULL);
2483 }
2484
2485 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2486 {
2487         seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2488         return 0;
2489 }
2490
2491 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2492 {
2493         return single_open(file, sg_proc_seq_show_devhdr, NULL);
2494 }
2495
2496 struct sg_proc_deviter {
2497         loff_t  index;
2498         size_t  max;
2499 };
2500
2501 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2502 {
2503         struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2504
2505         s->private = it;
2506         if (! it)
2507                 return NULL;
2508
2509         it->index = *pos;
2510         it->max = sg_last_dev();
2511         if (it->index >= it->max)
2512                 return NULL;
2513         return it;
2514 }
2515
2516 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2517 {
2518         struct sg_proc_deviter * it = s->private;
2519
2520         *pos = ++it->index;
2521         return (it->index < it->max) ? it : NULL;
2522 }
2523
2524 static void dev_seq_stop(struct seq_file *s, void *v)
2525 {
2526         kfree(s->private);
2527 }
2528
2529 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2530 {
2531         return seq_open(file, &dev_seq_ops);
2532 }
2533
2534 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2535 {
2536         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2537         Sg_device *sdp;
2538         struct scsi_device *scsidp;
2539         unsigned long iflags;
2540
2541         read_lock_irqsave(&sg_index_lock, iflags);
2542         sdp = it ? sg_lookup_dev(it->index) : NULL;
2543         if ((NULL == sdp) || (NULL == sdp->device) ||
2544             (atomic_read(&sdp->detaching)))
2545                 seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2546         else {
2547                 scsidp = sdp->device;
2548                 seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2549                               scsidp->host->host_no, scsidp->channel,
2550                               scsidp->id, scsidp->lun, (int) scsidp->type,
2551                               1,
2552                               (int) scsidp->queue_depth,
2553                               (int) atomic_read(&scsidp->device_busy),
2554                               (int) scsi_device_online(scsidp));
2555         }
2556         read_unlock_irqrestore(&sg_index_lock, iflags);
2557         return 0;
2558 }
2559
2560 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2561 {
2562         return seq_open(file, &devstrs_seq_ops);
2563 }
2564
2565 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2566 {
2567         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2568         Sg_device *sdp;
2569         struct scsi_device *scsidp;
2570         unsigned long iflags;
2571
2572         read_lock_irqsave(&sg_index_lock, iflags);
2573         sdp = it ? sg_lookup_dev(it->index) : NULL;
2574         scsidp = sdp ? sdp->device : NULL;
2575         if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2576                 seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2577                            scsidp->vendor, scsidp->model, scsidp->rev);
2578         else
2579                 seq_puts(s, "<no active device>\n");
2580         read_unlock_irqrestore(&sg_index_lock, iflags);
2581         return 0;
2582 }
2583
2584 /* must be called while holding sg_index_lock */
2585 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2586 {
2587         int k, m, new_interface, blen, usg;
2588         Sg_request *srp;
2589         Sg_fd *fp;
2590         const sg_io_hdr_t *hp;
2591         const char * cp;
2592         unsigned int ms;
2593
2594         k = 0;
2595         list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2596                 k++;
2597                 read_lock(&fp->rq_list_lock); /* irqs already disabled */
2598                 seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2599                            "(res)sgat=%d low_dma=%d\n", k,
2600                            jiffies_to_msecs(fp->timeout),
2601                            fp->reserve.bufflen,
2602                            (int) fp->reserve.k_use_sg,
2603                            (int) fp->low_dma);
2604                 seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2605                            (int) fp->cmd_q, (int) fp->force_packid,
2606                            (int) fp->keep_orphan);
2607                 for (m = 0, srp = fp->headrp;
2608                                 srp != NULL;
2609                                 ++m, srp = srp->nextrp) {
2610                         hp = &srp->header;
2611                         new_interface = (hp->interface_id == '\0') ? 0 : 1;
2612                         if (srp->res_used) {
2613                                 if (new_interface &&
2614                                     (SG_FLAG_MMAP_IO & hp->flags))
2615                                         cp = "     mmap>> ";
2616                                 else
2617                                         cp = "     rb>> ";
2618                         } else {
2619                                 if (SG_INFO_DIRECT_IO_MASK & hp->info)
2620                                         cp = "     dio>> ";
2621                                 else
2622                                         cp = "     ";
2623                         }
2624                         seq_puts(s, cp);
2625                         blen = srp->data.bufflen;
2626                         usg = srp->data.k_use_sg;
2627                         seq_puts(s, srp->done ?
2628                                  ((1 == srp->done) ?  "rcv:" : "fin:")
2629                                   : "act:");
2630                         seq_printf(s, " id=%d blen=%d",
2631                                    srp->header.pack_id, blen);
2632                         if (srp->done)
2633                                 seq_printf(s, " dur=%d", hp->duration);
2634                         else {
2635                                 ms = jiffies_to_msecs(jiffies);
2636                                 seq_printf(s, " t_o/elap=%d/%d",
2637                                         (new_interface ? hp->timeout :
2638                                                   jiffies_to_msecs(fp->timeout)),
2639                                         (ms > hp->duration ? ms - hp->duration : 0));
2640                         }
2641                         seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2642                                    (int) srp->data.cmd_opcode);
2643                 }
2644                 if (0 == m)
2645                         seq_puts(s, "     No requests active\n");
2646                 read_unlock(&fp->rq_list_lock);
2647         }
2648 }
2649
2650 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2651 {
2652         return seq_open(file, &debug_seq_ops);
2653 }
2654
2655 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2656 {
2657         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2658         Sg_device *sdp;
2659         unsigned long iflags;
2660
2661         if (it && (0 == it->index))
2662                 seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2663                            (int)it->max, sg_big_buff);
2664
2665         read_lock_irqsave(&sg_index_lock, iflags);
2666         sdp = it ? sg_lookup_dev(it->index) : NULL;
2667         if (NULL == sdp)
2668                 goto skip;
2669         read_lock(&sdp->sfd_lock);
2670         if (!list_empty(&sdp->sfds)) {
2671                 seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2672                 if (atomic_read(&sdp->detaching))
2673                         seq_puts(s, "detaching pending close ");
2674                 else if (sdp->device) {
2675                         struct scsi_device *scsidp = sdp->device;
2676
2677                         seq_printf(s, "%d:%d:%d:%llu   em=%d",
2678                                    scsidp->host->host_no,
2679                                    scsidp->channel, scsidp->id,
2680                                    scsidp->lun,
2681                                    scsidp->host->hostt->emulated);
2682                 }
2683                 seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2684                            sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2685                 sg_proc_debug_helper(s, sdp);
2686         }
2687         read_unlock(&sdp->sfd_lock);
2688 skip:
2689         read_unlock_irqrestore(&sg_index_lock, iflags);
2690         return 0;
2691 }
2692
2693 #endif                          /* CONFIG_SCSI_PROC_FS */
2694
2695 module_init(init_sg);
2696 module_exit(exit_sg);