drivers/scsi/st.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   4    file Documentation/scsi/st.rst for more information.
   5
   6    History:
   7    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   8    Contribution and ideas from several people including (in alphabetical
   9    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
  10    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  11    Michael Schaefer, J"org Weule, and Eric Youngdale.
  12
  13    Copyright 1992 - 2016 Kai Makisara
  14    email Kai.Makisara@kolumbus.fi
  15
  16    Some small formal changes - aeb, 950809
  17
  18    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  19  */
  20
  21 static const char *verstr = "20160209";
  22
  23 #include <linux/module.h>
  24
  25 #include <linux/compat.h>
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/mm.h>
  30 #include <linux/init.h>
  31 #include <linux/string.h>
  32 #include <linux/slab.h>
  33 #include <linux/errno.h>
  34 #include <linux/mtio.h>
  35 #include <linux/major.h>
  36 #include <linux/cdrom.h>
  37 #include <linux/ioctl.h>
  38 #include <linux/fcntl.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/blkdev.h>
  41 #include <linux/moduleparam.h>
  42 #include <linux/cdev.h>
  43 #include <linux/idr.h>
  44 #include <linux/delay.h>
  45 #include <linux/mutex.h>
  46
  47 #include <linux/uaccess.h>
  48 #include <asm/dma.h>
  49 #include <asm/unaligned.h>
  50
  51 #include <scsi/scsi.h>
  52 #include <scsi/scsi_dbg.h>
  53 #include <scsi/scsi_device.h>
  54 #include <scsi/scsi_driver.h>
  55 #include <scsi/scsi_eh.h>
  56 #include <scsi/scsi_host.h>
  57 #include <scsi/scsi_ioctl.h>
  58 #include <scsi/sg.h>
  59
  60
  61 /* The driver prints some debugging information on the console if DEBUG
  62    is defined and non-zero. */
  63 #define DEBUG 1
  64 #define NO_DEBUG 0
  65
  66 #define ST_DEB_MSG  KERN_NOTICE
  67 #if DEBUG
  68 /* The message level for the debug messages is currently set to KERN_NOTICE
  69    so that people can easily see the messages. Later when the debugging messages
  70    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  71 #define DEB(a) a
  72 #define DEBC(a) if (debugging) { a ; }
  73 #else
  74 #define DEB(a)
  75 #define DEBC(a)
  76 #endif
  77
  78 #define ST_KILOBYTE 1024
  79
  80 #include "st_options.h"
  81 #include "st.h"
  82
  83 static int buffer_kbs;
  84 static int max_sg_segs;
  85 static int try_direct_io = TRY_DIRECT_IO;
  86 static int try_rdio = 1;
  87 static int try_wdio = 1;
  88 static int debug_flag;
  89
  90 static struct class st_sysfs_class;
  91 static const struct attribute_group *st_dev_groups[];
  92 static const struct attribute_group *st_drv_groups[];
  93
  94 MODULE_AUTHOR("Kai Makisara");
  95 MODULE_DESCRIPTION("SCSI tape (st) driver");
  96 MODULE_LICENSE("GPL");
  97 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  98 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  99
 100 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
 101  * of sysfs parameters (which module_param doesn't yet support).
 102  * Sysfs parameters defined explicitly later.
 103  */
 104 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 105 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 106 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 107 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 108 module_param_named(try_direct_io, try_direct_io, int, 0);
 109 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 110 module_param_named(debug_flag, debug_flag, int, 0);
 111 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 112
 113
 114 /* Extra parameters for testing */
 115 module_param_named(try_rdio, try_rdio, int, 0);
 116 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 117 module_param_named(try_wdio, try_wdio, int, 0);
 118 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 119
 120 #ifndef MODULE
 121 static int write_threshold_kbs;  /* retained for compatibility */
 122 static struct st_dev_parm {
 123         char *name;
 124         int *val;
 125 } parms[] __initdata = {
 126         {
 127                 "buffer_kbs", &buffer_kbs
 128         },
 129         {       /* Retained for compatibility with 2.4 */
 130                 "write_threshold_kbs", &write_threshold_kbs
 131         },
 132         {
 133                 "max_sg_segs", NULL
 134         },
 135         {
 136                 "try_direct_io", &try_direct_io
 137         },
 138         {
 139                 "debug_flag", &debug_flag
 140         }
 141 };
 142 #endif
 143
 144 /* Restrict the number of modes so that names for all are assigned */
 145 #if ST_NBR_MODES > 16
 146 #error "Maximum number of modes is 16"
 147 #endif
 148 /* Bit reversed order to get same names for same minors with all
 149    mode counts */
 150 static const char *st_formats[] = {
 151         "",  "r", "k", "s", "l", "t", "o", "u",
 152         "m", "v", "p", "x", "a", "y", "q", "z"};
 153
 154 /* The default definitions have been moved to st_options.h */
 155
 156 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 157
 158 /* The buffer size should fit into the 24 bits for length in the
 159    6-byte SCSI read and write commands. */
 160 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 161 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 162 #endif
 163
 164 static int debugging = DEBUG;
 165
 166 #define MAX_RETRIES 0
 167 #define MAX_WRITE_RETRIES 0
 168 #define MAX_READY_RETRIES 0
 169 #define NO_TAPE  NOT_READY
 170
 171 #define ST_TIMEOUT (900 * HZ)
 172 #define ST_LONG_TIMEOUT (14000 * HZ)
 173
 174 /* Remove mode bits and auto-rewind bit (7) */
 175 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 176         (iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
 177 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 178
 179 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 180 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 181   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 182
 183 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 184    24 bits) */
 185 #define SET_DENS_AND_BLK 0x10001
 186
 187 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 188 static int st_max_sg_segs = ST_MAX_SG;
 189
 190 static int modes_defined;
 191
 192 static int enlarge_buffer(struct st_buffer *, int);
 193 static void clear_buffer(struct st_buffer *);
 194 static void normalize_buffer(struct st_buffer *);
 195 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 196 static int from_buffer(struct st_buffer *, char __user *, int);
 197 static void move_buffer_data(struct st_buffer *, int);
 198
 199 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 200                               unsigned long, size_t, int);
 201 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 202
 203 static int st_probe(struct device *);
 204 static int st_remove(struct device *);
 205
 206 static struct scsi_driver st_template = {
 207         .gendrv = {
 208                 .name           = "st",
 209                 .owner          = THIS_MODULE,
 210                 .probe          = st_probe,
 211                 .remove         = st_remove,
 212                 .groups         = st_drv_groups,
 213         },
 214 };
 215
 216 static int st_compression(struct scsi_tape *, int);
 217
 218 static int find_partition(struct scsi_tape *);
 219 static int switch_partition(struct scsi_tape *);
 220
 221 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 222
 223 static void scsi_tape_release(struct kref *);
 224
 225 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 226
 227 static DEFINE_MUTEX(st_ref_mutex);
 228 static DEFINE_SPINLOCK(st_index_lock);
 229 static DEFINE_SPINLOCK(st_use_lock);
 230 static DEFINE_IDR(st_index_idr);
 231
 232
 233 \f
 234 #ifndef SIGS_FROM_OSST
 235 #define SIGS_FROM_OSST \
 236         {"OnStream", "SC-", "", "osst"}, \
 237         {"OnStream", "DI-", "", "osst"}, \
 238         {"OnStream", "DP-", "", "osst"}, \
 239         {"OnStream", "USB", "", "osst"}, \
 240         {"OnStream", "FW-", "", "osst"}
 241 #endif
 242
 243 static struct scsi_tape *scsi_tape_get(int dev)
 244 {
 245         struct scsi_tape *STp = NULL;
 246
 247         mutex_lock(&st_ref_mutex);
 248         spin_lock(&st_index_lock);
 249
 250         STp = idr_find(&st_index_idr, dev);
 251         if (!STp) goto out;
 252
 253         kref_get(&STp->kref);
 254
 255         if (!STp->device)
 256                 goto out_put;
 257
 258         if (scsi_device_get(STp->device))
 259                 goto out_put;
 260
 261         goto out;
 262
 263 out_put:
 264         kref_put(&STp->kref, scsi_tape_release);
 265         STp = NULL;
 266 out:
 267         spin_unlock(&st_index_lock);
 268         mutex_unlock(&st_ref_mutex);
 269         return STp;
 270 }
 271
 272 static void scsi_tape_put(struct scsi_tape *STp)
 273 {
 274         struct scsi_device *sdev = STp->device;
 275
 276         mutex_lock(&st_ref_mutex);
 277         kref_put(&STp->kref, scsi_tape_release);
 278         scsi_device_put(sdev);
 279         mutex_unlock(&st_ref_mutex);
 280 }
 281
 282 struct st_reject_data {
 283         char *vendor;
 284         char *model;
 285         char *rev;
 286         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 287 };
 288
 289 static struct st_reject_data reject_list[] = {
 290         /* {"XXX", "Yy-", "", NULL},  example */
 291         SIGS_FROM_OSST,
 292         {NULL, }};
 293
 294 /* If the device signature is on the list of incompatible drives, the
 295    function returns a pointer to the name of the correct driver (if known) */
 296 static char * st_incompatible(struct scsi_device* SDp)
 297 {
 298         struct st_reject_data *rp;
 299
 300         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 301                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 302                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 303                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 304                         if (rp->driver_hint)
 305                                 return rp->driver_hint;
 306                         else
 307                                 return "unknown";
 308                 }
 309         return NULL;
 310 }
 311 \f
 312
 313 #define st_printk(prefix, t, fmt, a...) \
 314         sdev_prefix_printk(prefix, (t)->device, (t)->name, fmt, ##a)
 315 #ifdef DEBUG
 316 #define DEBC_printk(t, fmt, a...) \
 317         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 318 #else
 319 #define DEBC_printk(t, fmt, a...)
 320 #endif
 321
 322 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 323 {
 324         const u8 *ucp;
 325         const u8 *sense = SRpnt->sense;
 326
 327         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 328                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 329         s->flags = 0;
 330
 331         if (s->have_sense) {
 332                 s->deferred = 0;
 333                 s->remainder_valid =
 334                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 335                 switch (sense[0] & 0x7f) {
 336                 case 0x71:
 337                         s->deferred = 1;
 338                         fallthrough;
 339                 case 0x70:
 340                         s->fixed_format = 1;
 341                         s->flags = sense[2] & 0xe0;
 342                         break;
 343                 case 0x73:
 344                         s->deferred = 1;
 345                         fallthrough;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = STp->name;
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0, host bt 0x%x).\n",
 390                                result, host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 476         ktime_t now;
 477
 478         now = ktime_get();
 479         if (scmd->cmnd[0] == WRITE_6) {
 480                 now = ktime_sub(now, STp->stats->write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 482                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 483                 atomic64_inc(&STp->stats->write_cnt);
 484                 if (scmd->result) {
 485                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 486                                 - STp->buffer->cmdstat.residual,
 487                                 &STp->stats->write_byte_cnt);
 488                         if (STp->buffer->cmdstat.residual > 0)
 489                                 atomic64_inc(&STp->stats->resid_cnt);
 490                 } else
 491                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 492                                 &STp->stats->write_byte_cnt);
 493         } else if (scmd->cmnd[0] == READ_6) {
 494                 now = ktime_sub(now, STp->stats->read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 496                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 497                 atomic64_inc(&STp->stats->read_cnt);
 498                 if (scmd->result) {
 499                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 500                                 - STp->buffer->cmdstat.residual,
 501                                 &STp->stats->read_byte_cnt);
 502                         if (STp->buffer->cmdstat.residual > 0)
 503                                 atomic64_inc(&STp->stats->resid_cnt);
 504                 } else
 505                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 506                                 &STp->stats->read_byte_cnt);
 507         } else {
 508                 now = ktime_sub(now, STp->stats->other_time);
 509                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 510                 atomic64_inc(&STp->stats->other_cnt);
 511         }
 512         atomic64_dec(&STp->stats->in_flight);
 513 }
 514
 515 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 516 {
 517         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 518         struct st_request *SRpnt = req->end_io_data;
 519         struct scsi_tape *STp = SRpnt->stp;
 520         struct bio *tmp;
 521
 522         STp->buffer->cmdstat.midlevel_result = SRpnt->result = scmd->result;
 523         STp->buffer->cmdstat.residual = scmd->resid_len;
 524
 525         st_do_stats(STp, req);
 526
 527         tmp = SRpnt->bio;
 528         if (scmd->sense_len)
 529                 memcpy(SRpnt->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
 530         if (SRpnt->waiting)
 531                 complete(SRpnt->waiting);
 532
 533         blk_rq_unmap_user(tmp);
 534         blk_mq_free_request(req);
 535 }
 536
 537 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 538                            int data_direction, void *buffer, unsigned bufflen,
 539                            int timeout, int retries)
 540 {
 541         struct request *req;
 542         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 543         int err = 0;
 544         struct scsi_tape *STp = SRpnt->stp;
 545         struct scsi_cmnd *scmd;
 546
 547         req = scsi_alloc_request(SRpnt->stp->device->request_queue,
 548                         data_direction == DMA_TO_DEVICE ?
 549                         REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 550         if (IS_ERR(req))
 551                 return PTR_ERR(req);
 552         scmd = blk_mq_rq_to_pdu(req);
 553         req->rq_flags |= RQF_QUIET;
 554
 555         mdata->null_mapped = 1;
 556
 557         if (bufflen) {
 558                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 559                                       GFP_KERNEL);
 560                 if (err) {
 561                         blk_mq_free_request(req);
 562                         return err;
 563                 }
 564         }
 565
 566         atomic64_inc(&STp->stats->in_flight);
 567         if (cmd[0] == WRITE_6) {
 568                 atomic_set(&STp->stats->last_write_size, bufflen);
 569                 STp->stats->write_time = ktime_get();
 570         } else if (cmd[0] == READ_6) {
 571                 atomic_set(&STp->stats->last_read_size, bufflen);
 572                 STp->stats->read_time = ktime_get();
 573         } else {
 574                 STp->stats->other_time = ktime_get();
 575         }
 576
 577         SRpnt->bio = req->bio;
 578         scmd->cmd_len = COMMAND_SIZE(cmd[0]);
 579         memcpy(scmd->cmnd, cmd, scmd->cmd_len);
 580         req->timeout = timeout;
 581         scmd->allowed = retries;
 582         req->end_io_data = SRpnt;
 583
 584         blk_execute_rq_nowait(req, true, st_scsi_execute_end);
 585         return 0;
 586 }
 587
 588 /* Do the scsi command. Waits until command performed if do_wait is true.
 589    Otherwise write_behind_check() is used to check that the command
 590    has finished. */
 591 static struct st_request *
 592 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 593            int bytes, int direction, int timeout, int retries, int do_wait)
 594 {
 595         struct completion *waiting;
 596         struct rq_map_data *mdata = &STp->buffer->map_data;
 597         int ret;
 598
 599         /* if async, make sure there's no command outstanding */
 600         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 601                 st_printk(KERN_ERR, STp,
 602                           "Async command already active.\n");
 603                 if (signal_pending(current))
 604                         (STp->buffer)->syscall_result = (-EINTR);
 605                 else
 606                         (STp->buffer)->syscall_result = (-EBUSY);
 607                 return NULL;
 608         }
 609
 610         if (!SRpnt) {
 611                 SRpnt = st_allocate_request(STp);
 612                 if (!SRpnt)
 613                         return NULL;
 614         }
 615
 616         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 617            which IO is outstanding. It's nulled out when the IO completes. */
 618         if (!do_wait)
 619                 (STp->buffer)->last_SRpnt = SRpnt;
 620
 621         waiting = &STp->wait;
 622         init_completion(waiting);
 623         SRpnt->waiting = waiting;
 624
 625         if (STp->buffer->do_dio) {
 626                 mdata->page_order = 0;
 627                 mdata->nr_entries = STp->buffer->sg_segs;
 628                 mdata->pages = STp->buffer->mapped_pages;
 629         } else {
 630                 mdata->page_order = STp->buffer->reserved_page_order;
 631                 mdata->nr_entries =
 632                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 633                 mdata->pages = STp->buffer->reserved_pages;
 634                 mdata->offset = 0;
 635         }
 636
 637         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 638         STp->buffer->cmdstat.have_sense = 0;
 639         STp->buffer->syscall_result = 0;
 640
 641         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 642                               retries);
 643         if (ret) {
 644                 /* could not allocate the buffer or request was too large */
 645                 (STp->buffer)->syscall_result = (-EBUSY);
 646                 (STp->buffer)->last_SRpnt = NULL;
 647         } else if (do_wait) {
 648                 wait_for_completion(waiting);
 649                 SRpnt->waiting = NULL;
 650                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 651         }
 652
 653         return SRpnt;
 654 }
 655
 656
 657 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 658    write has been correct but EOM early warning reached, -EIO if write ended in
 659    error or zero if write successful. Asynchronous writes are used only in
 660    variable block mode. */
 661 static int write_behind_check(struct scsi_tape * STp)
 662 {
 663         int retval = 0;
 664         struct st_buffer *STbuffer;
 665         struct st_partstat *STps;
 666         struct st_cmdstatus *cmdstatp;
 667         struct st_request *SRpnt;
 668
 669         STbuffer = STp->buffer;
 670         if (!STbuffer->writing)
 671                 return 0;
 672
 673         DEB(
 674         if (STp->write_pending)
 675                 STp->nbr_waits++;
 676         else
 677                 STp->nbr_finished++;
 678         ) /* end DEB */
 679
 680         wait_for_completion(&(STp->wait));
 681         SRpnt = STbuffer->last_SRpnt;
 682         STbuffer->last_SRpnt = NULL;
 683         SRpnt->waiting = NULL;
 684
 685         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 686         st_release_request(SRpnt);
 687
 688         STbuffer->buffer_bytes -= STbuffer->writing;
 689         STps = &(STp->ps[STp->partition]);
 690         if (STps->drv_block >= 0) {
 691                 if (STp->block_size == 0)
 692                         STps->drv_block++;
 693                 else
 694                         STps->drv_block += STbuffer->writing / STp->block_size;
 695         }
 696
 697         cmdstatp = &STbuffer->cmdstat;
 698         if (STbuffer->syscall_result) {
 699                 retval = -EIO;
 700                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 701                     (cmdstatp->flags & SENSE_EOM) &&
 702                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 703                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 704                         /* EOM at write-behind, has all data been written? */
 705                         if (!cmdstatp->remainder_valid ||
 706                             cmdstatp->uremainder64 == 0)
 707                                 retval = -ENOSPC;
 708                 }
 709                 if (retval == -EIO)
 710                         STps->drv_block = -1;
 711         }
 712         STbuffer->writing = 0;
 713
 714         DEB(if (debugging && retval)
 715                     st_printk(ST_DEB_MSG, STp,
 716                                 "Async write error %x, return value %d.\n",
 717                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 718
 719         return retval;
 720 }
 721
 722
 723 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 724    it messes up the block number). */
 725 static int cross_eof(struct scsi_tape * STp, int forward)
 726 {
 727         struct st_request *SRpnt;
 728         unsigned char cmd[MAX_COMMAND_SIZE];
 729
 730         cmd[0] = SPACE;
 731         cmd[1] = 0x01;          /* Space FileMarks */
 732         if (forward) {
 733                 cmd[2] = cmd[3] = 0;
 734                 cmd[4] = 1;
 735         } else
 736                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 737         cmd[5] = 0;
 738
 739         DEBC_printk(STp, "Stepping over filemark %s.\n",
 740                     forward ? "forward" : "backward");
 741
 742         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 743                            STp->device->request_queue->rq_timeout,
 744                            MAX_RETRIES, 1);
 745         if (!SRpnt)
 746                 return (STp->buffer)->syscall_result;
 747
 748         st_release_request(SRpnt);
 749         SRpnt = NULL;
 750
 751         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 752                 st_printk(KERN_ERR, STp,
 753                           "Stepping over filemark %s failed.\n",
 754                           forward ? "forward" : "backward");
 755
 756         return (STp->buffer)->syscall_result;
 757 }
 758
 759
 760 /* Flush the write buffer (never need to write if variable blocksize). */
 761 static int st_flush_write_buffer(struct scsi_tape * STp)
 762 {
 763         int transfer, blks;
 764         int result;
 765         unsigned char cmd[MAX_COMMAND_SIZE];
 766         struct st_request *SRpnt;
 767         struct st_partstat *STps;
 768
 769         result = write_behind_check(STp);
 770         if (result)
 771                 return result;
 772
 773         result = 0;
 774         if (STp->dirty == 1) {
 775
 776                 transfer = STp->buffer->buffer_bytes;
 777                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 778
 779                 memset(cmd, 0, MAX_COMMAND_SIZE);
 780                 cmd[0] = WRITE_6;
 781                 cmd[1] = 1;
 782                 blks = transfer / STp->block_size;
 783                 cmd[2] = blks >> 16;
 784                 cmd[3] = blks >> 8;
 785                 cmd[4] = blks;
 786
 787                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 788                                    STp->device->request_queue->rq_timeout,
 789                                    MAX_WRITE_RETRIES, 1);
 790                 if (!SRpnt)
 791                         return (STp->buffer)->syscall_result;
 792
 793                 STps = &(STp->ps[STp->partition]);
 794                 if ((STp->buffer)->syscall_result != 0) {
 795                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 796
 797                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 798                             (cmdstatp->flags & SENSE_EOM) &&
 799                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 800                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 801                             (!cmdstatp->remainder_valid ||
 802                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 803                                 STp->dirty = 0;
 804                                 (STp->buffer)->buffer_bytes = 0;
 805                                 if (STps->drv_block >= 0)
 806                                         STps->drv_block += blks;
 807                                 result = (-ENOSPC);
 808                         } else {
 809                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 810                                 STps->drv_block = (-1);
 811                                 result = (-EIO);
 812                         }
 813                 } else {
 814                         if (STps->drv_block >= 0)
 815                                 STps->drv_block += blks;
 816                         STp->dirty = 0;
 817                         (STp->buffer)->buffer_bytes = 0;
 818                 }
 819                 st_release_request(SRpnt);
 820                 SRpnt = NULL;
 821         }
 822         return result;
 823 }
 824
 825
 826 /* Flush the tape buffer. The tape will be positioned correctly unless
 827    seek_next is true. */
 828 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 829 {
 830         int backspace, result;
 831         struct st_partstat *STps;
 832
 833         /*
 834          * If there was a bus reset, block further access
 835          * to this device.
 836          */
 837         if (STp->pos_unknown)
 838                 return (-EIO);
 839
 840         if (STp->ready != ST_READY)
 841                 return 0;
 842         STps = &(STp->ps[STp->partition]);
 843         if (STps->rw == ST_WRITING)     /* Writing */
 844                 return st_flush_write_buffer(STp);
 845
 846         if (STp->block_size == 0)
 847                 return 0;
 848
 849         backspace = ((STp->buffer)->buffer_bytes +
 850                      (STp->buffer)->read_pointer) / STp->block_size -
 851             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 852             STp->block_size;
 853         (STp->buffer)->buffer_bytes = 0;
 854         (STp->buffer)->read_pointer = 0;
 855         result = 0;
 856         if (!seek_next) {
 857                 if (STps->eof == ST_FM_HIT) {
 858                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 859                         if (!result)
 860                                 STps->eof = ST_NOEOF;
 861                         else {
 862                                 if (STps->drv_file >= 0)
 863                                         STps->drv_file++;
 864                                 STps->drv_block = 0;
 865                         }
 866                 }
 867                 if (!result && backspace > 0)
 868                         result = st_int_ioctl(STp, MTBSR, backspace);
 869         } else if (STps->eof == ST_FM_HIT) {
 870                 if (STps->drv_file >= 0)
 871                         STps->drv_file++;
 872                 STps->drv_block = 0;
 873                 STps->eof = ST_NOEOF;
 874         }
 875         return result;
 876
 877 }
 878 \f
 879 /* Set the mode parameters */
 880 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 881 {
 882         int set_it = 0;
 883         unsigned long arg;
 884
 885         if (!STp->density_changed &&
 886             STm->default_density >= 0 &&
 887             STm->default_density != STp->density) {
 888                 arg = STm->default_density;
 889                 set_it = 1;
 890         } else
 891                 arg = STp->density;
 892         arg <<= MT_ST_DENSITY_SHIFT;
 893         if (!STp->blksize_changed &&
 894             STm->default_blksize >= 0 &&
 895             STm->default_blksize != STp->block_size) {
 896                 arg |= STm->default_blksize;
 897                 set_it = 1;
 898         } else
 899                 arg |= STp->block_size;
 900         if (set_it &&
 901             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 902                 st_printk(KERN_WARNING, STp,
 903                           "Can't set default block size to %d bytes "
 904                           "and density %x.\n",
 905                           STm->default_blksize, STm->default_density);
 906                 if (modes_defined)
 907                         return (-EINVAL);
 908         }
 909         return 0;
 910 }
 911
 912
 913 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 914 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 915 {
 916         int retval;
 917
 918         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 919
 920         retval = scsi_set_medium_removal(STp->device,
 921                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 922         if (!retval)
 923                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 924         else
 925                 STp->door_locked = ST_LOCK_FAILS;
 926         return retval;
 927 }
 928
 929
 930 /* Set the internal state after reset */
 931 static void reset_state(struct scsi_tape *STp)
 932 {
 933         int i;
 934         struct st_partstat *STps;
 935
 936         STp->pos_unknown = 0;
 937         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 938                 STps = &(STp->ps[i]);
 939                 STps->rw = ST_IDLE;
 940                 STps->eof = ST_NOEOF;
 941                 STps->at_sm = 0;
 942                 STps->last_block_valid = 0;
 943                 STps->drv_block = -1;
 944                 STps->drv_file = -1;
 945         }
 946         if (STp->can_partitions) {
 947                 STp->partition = find_partition(STp);
 948                 if (STp->partition < 0)
 949                         STp->partition = 0;
 950                 STp->new_partition = STp->partition;
 951         }
 952 }
 953 \f
 954 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 955    error code. */
 956 #define CHKRES_READY       0
 957 #define CHKRES_NEW_SESSION 1
 958 #define CHKRES_NOT_READY   2
 959 #define CHKRES_NO_TAPE     3
 960
 961 #define MAX_ATTENTIONS    10
 962
 963 static int test_ready(struct scsi_tape *STp, int do_wait)
 964 {
 965         int attentions, waits, max_wait, scode;
 966         int retval = CHKRES_READY, new_session = 0;
 967         unsigned char cmd[MAX_COMMAND_SIZE];
 968         struct st_request *SRpnt = NULL;
 969         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 970
 971         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 972
 973         for (attentions=waits=0; ; ) {
 974                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 975                 cmd[0] = TEST_UNIT_READY;
 976                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 977                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 978
 979                 if (!SRpnt) {
 980                         retval = (STp->buffer)->syscall_result;
 981                         break;
 982                 }
 983
 984                 if (cmdstatp->have_sense) {
 985
 986                         scode = cmdstatp->sense_hdr.sense_key;
 987
 988                         if (scode == UNIT_ATTENTION) { /* New media? */
 989                                 new_session = 1;
 990                                 if (attentions < MAX_ATTENTIONS) {
 991                                         attentions++;
 992                                         continue;
 993                                 }
 994                                 else {
 995                                         retval = (-EIO);
 996                                         break;
 997                                 }
 998                         }
 999
1000                         if (scode == NOT_READY) {
1001                                 if (waits < max_wait) {
1002                                         if (msleep_interruptible(1000)) {
1003                                                 retval = (-EINTR);
1004                                                 break;
1005                                         }
1006                                         waits++;
1007                                         continue;
1008                                 }
1009                                 else {
1010                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1011                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1012                                                 retval = CHKRES_NO_TAPE;
1013                                         else
1014                                                 retval = CHKRES_NOT_READY;
1015                                         break;
1016                                 }
1017                         }
1018                 }
1019
1020                 retval = (STp->buffer)->syscall_result;
1021                 if (!retval)
1022                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1023                 break;
1024         }
1025
1026         if (SRpnt != NULL)
1027                 st_release_request(SRpnt);
1028         return retval;
1029 }
1030
1031
1032 /* See if the drive is ready and gather information about the tape. Return values:
1033    < 0   negative error code from errno.h
1034    0     drive ready
1035    1     drive not ready (possibly no tape)
1036 */
1037 static int check_tape(struct scsi_tape *STp, struct file *filp)
1038 {
1039         int i, retval, new_session = 0, do_wait;
1040         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1041         unsigned short st_flags = filp->f_flags;
1042         struct st_request *SRpnt = NULL;
1043         struct st_modedef *STm;
1044         struct st_partstat *STps;
1045         struct inode *inode = file_inode(filp);
1046         int mode = TAPE_MODE(inode);
1047
1048         STp->ready = ST_READY;
1049
1050         if (mode != STp->current_mode) {
1051                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1052                             STp->current_mode, mode);
1053                 new_session = 1;
1054                 STp->current_mode = mode;
1055         }
1056         STm = &(STp->modes[STp->current_mode]);
1057
1058         saved_cleaning = STp->cleaning_req;
1059         STp->cleaning_req = 0;
1060
1061         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1062         retval = test_ready(STp, do_wait);
1063
1064         if (retval < 0)
1065             goto err_out;
1066
1067         if (retval == CHKRES_NEW_SESSION) {
1068                 STp->pos_unknown = 0;
1069                 STp->partition = STp->new_partition = 0;
1070                 if (STp->can_partitions)
1071                         STp->nbr_partitions = 1; /* This guess will be updated later
1072                                                     if necessary */
1073                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1074                         STps = &(STp->ps[i]);
1075                         STps->rw = ST_IDLE;
1076                         STps->eof = ST_NOEOF;
1077                         STps->at_sm = 0;
1078                         STps->last_block_valid = 0;
1079                         STps->drv_block = 0;
1080                         STps->drv_file = 0;
1081                 }
1082                 new_session = 1;
1083         }
1084         else {
1085                 STp->cleaning_req |= saved_cleaning;
1086
1087                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1088                         if (retval == CHKRES_NO_TAPE)
1089                                 STp->ready = ST_NO_TAPE;
1090                         else
1091                                 STp->ready = ST_NOT_READY;
1092
1093                         STp->density = 0;       /* Clear the erroneous "residue" */
1094                         STp->write_prot = 0;
1095                         STp->block_size = 0;
1096                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1097                         STp->partition = STp->new_partition = 0;
1098                         STp->door_locked = ST_UNLOCKED;
1099                         return CHKRES_NOT_READY;
1100                 }
1101         }
1102
1103         if (STp->omit_blklims)
1104                 STp->min_block = STp->max_block = (-1);
1105         else {
1106                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1107                 cmd[0] = READ_BLOCK_LIMITS;
1108
1109                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1110                                    STp->device->request_queue->rq_timeout,
1111                                    MAX_READY_RETRIES, 1);
1112                 if (!SRpnt) {
1113                         retval = (STp->buffer)->syscall_result;
1114                         goto err_out;
1115                 }
1116
1117                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1118                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1119                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1120                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1121                             (STp->buffer)->b_data[5];
1122                         if ( DEB( debugging || ) !STp->inited)
1123                                 st_printk(KERN_INFO, STp,
1124                                           "Block limits %d - %d bytes.\n",
1125                                           STp->min_block, STp->max_block);
1126                 } else {
1127                         STp->min_block = STp->max_block = (-1);
1128                         DEBC_printk(STp, "Can't read block limits.\n");
1129                 }
1130         }
1131
1132         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1133         cmd[0] = MODE_SENSE;
1134         cmd[4] = 12;
1135
1136         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1137                            STp->device->request_queue->rq_timeout,
1138                            MAX_READY_RETRIES, 1);
1139         if (!SRpnt) {
1140                 retval = (STp->buffer)->syscall_result;
1141                 goto err_out;
1142         }
1143
1144         if ((STp->buffer)->syscall_result != 0) {
1145                 DEBC_printk(STp, "No Mode Sense.\n");
1146                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1147                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1148                 STp->drv_write_prot = 0;
1149         } else {
1150                 DEBC_printk(STp,"Mode sense. Length %d, "
1151                             "medium %x, WBS %x, BLL %d\n",
1152                             (STp->buffer)->b_data[0],
1153                             (STp->buffer)->b_data[1],
1154                             (STp->buffer)->b_data[2],
1155                             (STp->buffer)->b_data[3]);
1156
1157                 if ((STp->buffer)->b_data[3] >= 8) {
1158                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1159                         STp->density = (STp->buffer)->b_data[4];
1160                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1161                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1162                         DEBC_printk(STp, "Density %x, tape length: %x, "
1163                                     "drv buffer: %d\n",
1164                                     STp->density,
1165                                     (STp->buffer)->b_data[5] * 65536 +
1166                                     (STp->buffer)->b_data[6] * 256 +
1167                                     (STp->buffer)->b_data[7],
1168                                     STp->drv_buffer);
1169                 }
1170                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1171                 if (!STp->drv_buffer && STp->immediate_filemark) {
1172                         st_printk(KERN_WARNING, STp,
1173                                   "non-buffered tape: disabling "
1174                                   "writing immediate filemarks\n");
1175                         STp->immediate_filemark = 0;
1176                 }
1177         }
1178         st_release_request(SRpnt);
1179         SRpnt = NULL;
1180         STp->inited = 1;
1181
1182         if (STp->block_size > 0)
1183                 (STp->buffer)->buffer_blocks =
1184                         (STp->buffer)->buffer_size / STp->block_size;
1185         else
1186                 (STp->buffer)->buffer_blocks = 1;
1187         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1188
1189         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1190                     STp->block_size, (STp->buffer)->buffer_size,
1191                     (STp->buffer)->buffer_blocks);
1192
1193         if (STp->drv_write_prot) {
1194                 STp->write_prot = 1;
1195
1196                 DEBC_printk(STp, "Write protected\n");
1197
1198                 if (do_wait &&
1199                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1200                      (st_flags & O_ACCMODE) == O_RDWR)) {
1201                         retval = (-EROFS);
1202                         goto err_out;
1203                 }
1204         }
1205
1206         if (STp->can_partitions && STp->nbr_partitions < 1) {
1207                 /* This code is reached when the device is opened for the first time
1208                    after the driver has been initialized with tape in the drive and the
1209                    partition support has been enabled. */
1210                 DEBC_printk(STp, "Updating partition number in status.\n");
1211                 if ((STp->partition = find_partition(STp)) < 0) {
1212                         retval = STp->partition;
1213                         goto err_out;
1214                 }
1215                 STp->new_partition = STp->partition;
1216                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1217         }
1218
1219         if (new_session) {      /* Change the drive parameters for the new mode */
1220                 STp->density_changed = STp->blksize_changed = 0;
1221                 STp->compression_changed = 0;
1222                 if (!(STm->defaults_for_writes) &&
1223                     (retval = set_mode_densblk(STp, STm)) < 0)
1224                     goto err_out;
1225
1226                 if (STp->default_drvbuffer != 0xff) {
1227                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1228                                 st_printk(KERN_WARNING, STp,
1229                                           "Can't set default drive "
1230                                           "buffering to %d.\n",
1231                                           STp->default_drvbuffer);
1232                 }
1233         }
1234
1235         return CHKRES_READY;
1236
1237  err_out:
1238         return retval;
1239 }
1240
1241
1242 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1243    module count. */
1244 static int st_open(struct inode *inode, struct file *filp)
1245 {
1246         int i, retval = (-EIO);
1247         int resumed = 0;
1248         struct scsi_tape *STp;
1249         struct st_partstat *STps;
1250         int dev = TAPE_NR(inode);
1251
1252         /*
1253          * We really want to do nonseekable_open(inode, filp); here, but some
1254          * versions of tar incorrectly call lseek on tapes and bail out if that
1255          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1256          */
1257         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1258
1259         if (!(STp = scsi_tape_get(dev))) {
1260                 return -ENXIO;
1261         }
1262
1263         filp->private_data = STp;
1264
1265         spin_lock(&st_use_lock);
1266         if (STp->in_use) {
1267                 spin_unlock(&st_use_lock);
1268                 DEBC_printk(STp, "Device already in use.\n");
1269                 scsi_tape_put(STp);
1270                 return (-EBUSY);
1271         }
1272
1273         STp->in_use = 1;
1274         spin_unlock(&st_use_lock);
1275         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1276
1277         if (scsi_autopm_get_device(STp->device) < 0) {
1278                 retval = -EIO;
1279                 goto err_out;
1280         }
1281         resumed = 1;
1282         if (!scsi_block_when_processing_errors(STp->device)) {
1283                 retval = (-ENXIO);
1284                 goto err_out;
1285         }
1286
1287         /* See that we have at least a one page buffer available */
1288         if (!enlarge_buffer(STp->buffer, PAGE_SIZE)) {
1289                 st_printk(KERN_WARNING, STp,
1290                           "Can't allocate one page tape buffer.\n");
1291                 retval = (-EOVERFLOW);
1292                 goto err_out;
1293         }
1294
1295         (STp->buffer)->cleared = 0;
1296         (STp->buffer)->writing = 0;
1297         (STp->buffer)->syscall_result = 0;
1298
1299         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1300
1301         STp->dirty = 0;
1302         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1303                 STps = &(STp->ps[i]);
1304                 STps->rw = ST_IDLE;
1305         }
1306         STp->try_dio_now = STp->try_dio;
1307         STp->recover_count = 0;
1308         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1309              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1310
1311         retval = check_tape(STp, filp);
1312         if (retval < 0)
1313                 goto err_out;
1314         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1315             retval != CHKRES_READY) {
1316                 if (STp->ready == NO_TAPE)
1317                         retval = (-ENOMEDIUM);
1318                 else
1319                         retval = (-EIO);
1320                 goto err_out;
1321         }
1322         return 0;
1323
1324  err_out:
1325         normalize_buffer(STp->buffer);
1326         spin_lock(&st_use_lock);
1327         STp->in_use = 0;
1328         spin_unlock(&st_use_lock);
1329         if (resumed)
1330                 scsi_autopm_put_device(STp->device);
1331         scsi_tape_put(STp);
1332         return retval;
1333
1334 }
1335 \f
1336
1337 /* Flush the tape buffer before close */
1338 static int st_flush(struct file *filp, fl_owner_t id)
1339 {
1340         int result = 0, result2;
1341         unsigned char cmd[MAX_COMMAND_SIZE];
1342         struct st_request *SRpnt;
1343         struct scsi_tape *STp = filp->private_data;
1344         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1345         struct st_partstat *STps = &(STp->ps[STp->partition]);
1346
1347         if (file_count(filp) > 1)
1348                 return 0;
1349
1350         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1351                 result = st_flush_write_buffer(STp);
1352                 if (result != 0 && result != (-ENOSPC))
1353                         goto out;
1354         }
1355
1356         if (STp->can_partitions &&
1357             (result2 = switch_partition(STp)) < 0) {
1358                 DEBC_printk(STp, "switch_partition at close failed.\n");
1359                 if (result == 0)
1360                         result = result2;
1361                 goto out;
1362         }
1363
1364         DEBC( if (STp->nbr_requests)
1365                 st_printk(KERN_DEBUG, STp,
1366                           "Number of r/w requests %d, dio used in %d, "
1367                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1368                           STp->nbr_pages));
1369
1370         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1371                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1372
1373 #if DEBUG
1374                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1375                             STp->nbr_waits, STp->nbr_finished);
1376 #endif
1377                 memset(cmd, 0, MAX_COMMAND_SIZE);
1378                 cmd[0] = WRITE_FILEMARKS;
1379                 if (STp->immediate_filemark)
1380                         cmd[1] = 1;
1381                 cmd[4] = 1 + STp->two_fm;
1382
1383                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1384                                    STp->device->request_queue->rq_timeout,
1385                                    MAX_WRITE_RETRIES, 1);
1386                 if (!SRpnt) {
1387                         result = (STp->buffer)->syscall_result;
1388                         goto out;
1389                 }
1390
1391                 if (STp->buffer->syscall_result == 0 ||
1392                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1393                      (cmdstatp->flags & SENSE_EOM) &&
1394                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1395                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1396                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1397                         /* Write successful at EOM */
1398                         st_release_request(SRpnt);
1399                         SRpnt = NULL;
1400                         if (STps->drv_file >= 0)
1401                                 STps->drv_file++;
1402                         STps->drv_block = 0;
1403                         if (STp->two_fm)
1404                                 cross_eof(STp, 0);
1405                         STps->eof = ST_FM;
1406                 }
1407                 else { /* Write error */
1408                         st_release_request(SRpnt);
1409                         SRpnt = NULL;
1410                         st_printk(KERN_ERR, STp,
1411                                   "Error on write filemark.\n");
1412                         if (result == 0)
1413                                 result = (-EIO);
1414                 }
1415
1416                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1417         } else if (!STp->rew_at_close) {
1418                 STps = &(STp->ps[STp->partition]);
1419                 if (!STm->sysv || STps->rw != ST_READING) {
1420                         if (STp->can_bsr)
1421                                 result = flush_buffer(STp, 0);
1422                         else if (STps->eof == ST_FM_HIT) {
1423                                 result = cross_eof(STp, 0);
1424                                 if (result) {
1425                                         if (STps->drv_file >= 0)
1426                                                 STps->drv_file++;
1427                                         STps->drv_block = 0;
1428                                         STps->eof = ST_FM;
1429                                 } else
1430                                         STps->eof = ST_NOEOF;
1431                         }
1432                 } else if ((STps->eof == ST_NOEOF &&
1433                             !(result = cross_eof(STp, 1))) ||
1434                            STps->eof == ST_FM_HIT) {
1435                         if (STps->drv_file >= 0)
1436                                 STps->drv_file++;
1437                         STps->drv_block = 0;
1438                         STps->eof = ST_FM;
1439                 }
1440         }
1441
1442       out:
1443         if (STp->rew_at_close) {
1444                 result2 = st_int_ioctl(STp, MTREW, 1);
1445                 if (result == 0)
1446                         result = result2;
1447         }
1448         return result;
1449 }
1450
1451
1452 /* Close the device and release it. BKL is not needed: this is the only thread
1453    accessing this tape. */
1454 static int st_release(struct inode *inode, struct file *filp)
1455 {
1456         struct scsi_tape *STp = filp->private_data;
1457
1458         if (STp->door_locked == ST_LOCKED_AUTO)
1459                 do_door_lock(STp, 0);
1460
1461         normalize_buffer(STp->buffer);
1462         spin_lock(&st_use_lock);
1463         STp->in_use = 0;
1464         spin_unlock(&st_use_lock);
1465         scsi_autopm_put_device(STp->device);
1466         scsi_tape_put(STp);
1467
1468         return 0;
1469 }
1470
1471 /* The checks common to both reading and writing */
1472 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1473 {
1474         ssize_t retval = 0;
1475
1476         /*
1477          * If we are in the middle of error recovery, don't let anyone
1478          * else try and use this device.  Also, if error recovery fails, it
1479          * may try and take the device offline, in which case all further
1480          * access to the device is prohibited.
1481          */
1482         if (!scsi_block_when_processing_errors(STp->device)) {
1483                 retval = (-ENXIO);
1484                 goto out;
1485         }
1486
1487         if (STp->ready != ST_READY) {
1488                 if (STp->ready == ST_NO_TAPE)
1489                         retval = (-ENOMEDIUM);
1490                 else
1491                         retval = (-EIO);
1492                 goto out;
1493         }
1494
1495         if (! STp->modes[STp->current_mode].defined) {
1496                 retval = (-ENXIO);
1497                 goto out;
1498         }
1499
1500
1501         /*
1502          * If there was a bus reset, block further access
1503          * to this device.
1504          */
1505         if (STp->pos_unknown) {
1506                 retval = (-EIO);
1507                 goto out;
1508         }
1509
1510         if (count == 0)
1511                 goto out;
1512
1513         DEB(
1514         if (!STp->in_use) {
1515                 st_printk(ST_DEB_MSG, STp,
1516                           "Incorrect device.\n");
1517                 retval = (-EIO);
1518                 goto out;
1519         } ) /* end DEB */
1520
1521         if (STp->can_partitions &&
1522             (retval = switch_partition(STp)) < 0)
1523                 goto out;
1524
1525         if (STp->block_size == 0 && STp->max_block > 0 &&
1526             (count < STp->min_block || count > STp->max_block)) {
1527                 retval = (-EINVAL);
1528                 goto out;
1529         }
1530
1531         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1532             !do_door_lock(STp, 1))
1533                 STp->door_locked = ST_LOCKED_AUTO;
1534
1535  out:
1536         return retval;
1537 }
1538
1539
1540 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1541                            size_t count, int is_read)
1542 {
1543         int i, bufsize, retval = 0;
1544         struct st_buffer *STbp = STp->buffer;
1545
1546         if (is_read)
1547                 i = STp->try_dio_now && try_rdio;
1548         else
1549                 i = STp->try_dio_now && try_wdio;
1550
1551         if (i && ((unsigned long)buf & queue_dma_alignment(
1552                                         STp->device->request_queue)) == 0) {
1553                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1554                                        count, (is_read ? READ : WRITE));
1555                 if (i > 0) {
1556                         STbp->do_dio = i;
1557                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1558                 }
1559                 else
1560                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1561                 STbp->sg_segs = STbp->do_dio;
1562                 DEB(
1563                      if (STbp->do_dio) {
1564                         STp->nbr_dio++;
1565                         STp->nbr_pages += STbp->do_dio;
1566                      }
1567                 )
1568         } else
1569                 STbp->do_dio = 0;
1570         DEB( STp->nbr_requests++; )
1571
1572         if (!STbp->do_dio) {
1573                 if (STp->block_size)
1574                         bufsize = STp->block_size > st_fixed_buffer_size ?
1575                                 STp->block_size : st_fixed_buffer_size;
1576                 else {
1577                         bufsize = count;
1578                         /* Make sure that data from previous user is not leaked even if
1579                            HBA does not return correct residual */
1580                         if (is_read && STp->sili && !STbp->cleared)
1581                                 clear_buffer(STbp);
1582                 }
1583
1584                 if (bufsize > STbp->buffer_size &&
1585                     !enlarge_buffer(STbp, bufsize)) {
1586                         st_printk(KERN_WARNING, STp,
1587                                   "Can't allocate %d byte tape buffer.\n",
1588                                   bufsize);
1589                         retval = (-EOVERFLOW);
1590                         goto out;
1591                 }
1592                 if (STp->block_size)
1593                         STbp->buffer_blocks = bufsize / STp->block_size;
1594         }
1595
1596  out:
1597         return retval;
1598 }
1599
1600
1601 /* Can be called more than once after each setup_buffer() */
1602 static void release_buffering(struct scsi_tape *STp, int is_read)
1603 {
1604         struct st_buffer *STbp;
1605
1606         STbp = STp->buffer;
1607         if (STbp->do_dio) {
1608                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1609                 STbp->do_dio = 0;
1610                 STbp->sg_segs = 0;
1611         }
1612 }
1613
1614
1615 /* Write command */
1616 static ssize_t
1617 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1618 {
1619         ssize_t total;
1620         ssize_t i, do_count, blks, transfer;
1621         ssize_t retval;
1622         int undone, retry_eot = 0, scode;
1623         int async_write;
1624         unsigned char cmd[MAX_COMMAND_SIZE];
1625         const char __user *b_point;
1626         struct st_request *SRpnt = NULL;
1627         struct scsi_tape *STp = filp->private_data;
1628         struct st_modedef *STm;
1629         struct st_partstat *STps;
1630         struct st_buffer *STbp;
1631
1632         if (mutex_lock_interruptible(&STp->lock))
1633                 return -ERESTARTSYS;
1634
1635         retval = rw_checks(STp, filp, count);
1636         if (retval || count == 0)
1637                 goto out;
1638
1639         /* Write must be integral number of blocks */
1640         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1641                 st_printk(KERN_WARNING, STp,
1642                           "Write not multiple of tape block size.\n");
1643                 retval = (-EINVAL);
1644                 goto out;
1645         }
1646
1647         STm = &(STp->modes[STp->current_mode]);
1648         STps = &(STp->ps[STp->partition]);
1649
1650         if (STp->write_prot) {
1651                 retval = (-EACCES);
1652                 goto out;
1653         }
1654
1655
1656         if (STps->rw == ST_READING) {
1657                 retval = flush_buffer(STp, 0);
1658                 if (retval)
1659                         goto out;
1660                 STps->rw = ST_WRITING;
1661         } else if (STps->rw != ST_WRITING &&
1662                    STps->drv_file == 0 && STps->drv_block == 0) {
1663                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1664                         goto out;
1665                 if (STm->default_compression != ST_DONT_TOUCH &&
1666                     !(STp->compression_changed)) {
1667                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1668                                 st_printk(KERN_WARNING, STp,
1669                                           "Can't set default compression.\n");
1670                                 if (modes_defined) {
1671                                         retval = (-EINVAL);
1672                                         goto out;
1673                                 }
1674                         }
1675                 }
1676         }
1677
1678         STbp = STp->buffer;
1679         i = write_behind_check(STp);
1680         if (i) {
1681                 if (i == -ENOSPC)
1682                         STps->eof = ST_EOM_OK;
1683                 else
1684                         STps->eof = ST_EOM_ERROR;
1685         }
1686
1687         if (STps->eof == ST_EOM_OK) {
1688                 STps->eof = ST_EOD_1;  /* allow next write */
1689                 retval = (-ENOSPC);
1690                 goto out;
1691         }
1692         else if (STps->eof == ST_EOM_ERROR) {
1693                 retval = (-EIO);
1694                 goto out;
1695         }
1696
1697         /* Check the buffer readability in cases where copy_user might catch
1698            the problems after some tape movement. */
1699         if (STp->block_size != 0 &&
1700             !STbp->do_dio &&
1701             (copy_from_user(&i, buf, 1) != 0 ||
1702              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1703                 retval = (-EFAULT);
1704                 goto out;
1705         }
1706
1707         retval = setup_buffering(STp, buf, count, 0);
1708         if (retval)
1709                 goto out;
1710
1711         total = count;
1712
1713         memset(cmd, 0, MAX_COMMAND_SIZE);
1714         cmd[0] = WRITE_6;
1715         cmd[1] = (STp->block_size != 0);
1716
1717         STps->rw = ST_WRITING;
1718
1719         b_point = buf;
1720         while (count > 0 && !retry_eot) {
1721
1722                 if (STbp->do_dio) {
1723                         do_count = count;
1724                 }
1725                 else {
1726                         if (STp->block_size == 0)
1727                                 do_count = count;
1728                         else {
1729                                 do_count = STbp->buffer_blocks * STp->block_size -
1730                                         STbp->buffer_bytes;
1731                                 if (do_count > count)
1732                                         do_count = count;
1733                         }
1734
1735                         i = append_to_buffer(b_point, STbp, do_count);
1736                         if (i) {
1737                                 retval = i;
1738                                 goto out;
1739                         }
1740                 }
1741                 count -= do_count;
1742                 b_point += do_count;
1743
1744                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1745                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1746
1747                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1748                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1749                     STbp->buffer_bytes < STbp->buffer_size) {
1750                         STp->dirty = 1;
1751                         /* Don't write a buffer that is not full enough. */
1752                         if (!async_write && count == 0)
1753                                 break;
1754                 }
1755
1756         retry_write:
1757                 if (STp->block_size == 0)
1758                         blks = transfer = do_count;
1759                 else {
1760                         if (!STbp->do_dio)
1761                                 blks = STbp->buffer_bytes;
1762                         else
1763                                 blks = do_count;
1764                         blks /= STp->block_size;
1765                         transfer = blks * STp->block_size;
1766                 }
1767                 cmd[2] = blks >> 16;
1768                 cmd[3] = blks >> 8;
1769                 cmd[4] = blks;
1770
1771                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1772                                    STp->device->request_queue->rq_timeout,
1773                                    MAX_WRITE_RETRIES, !async_write);
1774                 if (!SRpnt) {
1775                         retval = STbp->syscall_result;
1776                         goto out;
1777                 }
1778                 if (async_write && !STbp->syscall_result) {
1779                         STbp->writing = transfer;
1780                         STp->dirty = !(STbp->writing ==
1781                                        STbp->buffer_bytes);
1782                         SRpnt = NULL;  /* Prevent releasing this request! */
1783                         DEB( STp->write_pending = 1; )
1784                         break;
1785                 }
1786
1787                 if (STbp->syscall_result != 0) {
1788                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1789
1790                         DEBC_printk(STp, "Error on write:\n");
1791                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1792                                 scode = cmdstatp->sense_hdr.sense_key;
1793                                 if (cmdstatp->remainder_valid)
1794                                         undone = (int)cmdstatp->uremainder64;
1795                                 else if (STp->block_size == 0 &&
1796                                          scode == VOLUME_OVERFLOW)
1797                                         undone = transfer;
1798                                 else
1799                                         undone = 0;
1800                                 if (STp->block_size != 0)
1801                                         undone *= STp->block_size;
1802                                 if (undone <= do_count) {
1803                                         /* Only data from this write is not written */
1804                                         count += undone;
1805                                         b_point -= undone;
1806                                         do_count -= undone;
1807                                         if (STp->block_size)
1808                                                 blks = (transfer - undone) / STp->block_size;
1809                                         STps->eof = ST_EOM_OK;
1810                                         /* Continue in fixed block mode if all written
1811                                            in this request but still something left to write
1812                                            (retval left to zero)
1813                                         */
1814                                         if (STp->block_size == 0 ||
1815                                             undone > 0 || count == 0)
1816                                                 retval = (-ENOSPC); /* EOM within current request */
1817                                         DEBC_printk(STp, "EOM with %d "
1818                                                     "bytes unwritten.\n",
1819                                                     (int)count);
1820                                 } else {
1821                                         /* EOT within data buffered earlier (possible only
1822                                            in fixed block mode without direct i/o) */
1823                                         if (!retry_eot && !cmdstatp->deferred &&
1824                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1825                                                 move_buffer_data(STp->buffer, transfer - undone);
1826                                                 retry_eot = 1;
1827                                                 if (STps->drv_block >= 0) {
1828                                                         STps->drv_block += (transfer - undone) /
1829                                                                 STp->block_size;
1830                                                 }
1831                                                 STps->eof = ST_EOM_OK;
1832                                                 DEBC_printk(STp, "Retry "
1833                                                             "write of %d "
1834                                                             "bytes at EOM.\n",
1835                                                             STp->buffer->buffer_bytes);
1836                                                 goto retry_write;
1837                                         }
1838                                         else {
1839                                                 /* Either error within data buffered by driver or
1840                                                    failed retry */
1841                                                 count -= do_count;
1842                                                 blks = do_count = 0;
1843                                                 STps->eof = ST_EOM_ERROR;
1844                                                 STps->drv_block = (-1); /* Too cautious? */
1845                                                 retval = (-EIO);        /* EOM for old data */
1846                                                 DEBC_printk(STp, "EOM with "
1847                                                             "lost data.\n");
1848                                         }
1849                                 }
1850                         } else {
1851                                 count += do_count;
1852                                 STps->drv_block = (-1);         /* Too cautious? */
1853                                 retval = STbp->syscall_result;
1854                         }
1855
1856                 }
1857
1858                 if (STps->drv_block >= 0) {
1859                         if (STp->block_size == 0)
1860                                 STps->drv_block += (do_count > 0);
1861                         else
1862                                 STps->drv_block += blks;
1863                 }
1864
1865                 STbp->buffer_bytes = 0;
1866                 STp->dirty = 0;
1867
1868                 if (retval || retry_eot) {
1869                         if (count < total)
1870                                 retval = total - count;
1871                         goto out;
1872                 }
1873         }
1874
1875         if (STps->eof == ST_EOD_1)
1876                 STps->eof = ST_EOM_OK;
1877         else if (STps->eof != ST_EOM_OK)
1878                 STps->eof = ST_NOEOF;
1879         retval = total - count;
1880
1881  out:
1882         if (SRpnt != NULL)
1883                 st_release_request(SRpnt);
1884         release_buffering(STp, 0);
1885         mutex_unlock(&STp->lock);
1886
1887         return retval;
1888 }
1889 \f
1890 /* Read data from the tape. Returns zero in the normal case, one if the
1891    eof status has changed, and the negative error code in case of a
1892    fatal error. Otherwise updates the buffer and the eof state.
1893
1894    Does release user buffer mapping if it is set.
1895 */
1896 static long read_tape(struct scsi_tape *STp, long count,
1897                       struct st_request ** aSRpnt)
1898 {
1899         int transfer, blks, bytes;
1900         unsigned char cmd[MAX_COMMAND_SIZE];
1901         struct st_request *SRpnt;
1902         struct st_modedef *STm;
1903         struct st_partstat *STps;
1904         struct st_buffer *STbp;
1905         int retval = 0;
1906
1907         if (count == 0)
1908                 return 0;
1909
1910         STm = &(STp->modes[STp->current_mode]);
1911         STps = &(STp->ps[STp->partition]);
1912         if (STps->eof == ST_FM_HIT)
1913                 return 1;
1914         STbp = STp->buffer;
1915
1916         if (STp->block_size == 0)
1917                 blks = bytes = count;
1918         else {
1919                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1920                         blks = (STp->buffer)->buffer_blocks;
1921                         bytes = blks * STp->block_size;
1922                 } else {
1923                         bytes = count;
1924                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1925                                 bytes = (STp->buffer)->buffer_size;
1926                         blks = bytes / STp->block_size;
1927                         bytes = blks * STp->block_size;
1928                 }
1929         }
1930
1931         memset(cmd, 0, MAX_COMMAND_SIZE);
1932         cmd[0] = READ_6;
1933         cmd[1] = (STp->block_size != 0);
1934         if (!cmd[1] && STp->sili)
1935                 cmd[1] |= 2;
1936         cmd[2] = blks >> 16;
1937         cmd[3] = blks >> 8;
1938         cmd[4] = blks;
1939
1940         SRpnt = *aSRpnt;
1941         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1942                            STp->device->request_queue->rq_timeout,
1943                            MAX_RETRIES, 1);
1944         release_buffering(STp, 1);
1945         *aSRpnt = SRpnt;
1946         if (!SRpnt)
1947                 return STbp->syscall_result;
1948
1949         STbp->read_pointer = 0;
1950         STps->at_sm = 0;
1951
1952         /* Something to check */
1953         if (STbp->syscall_result) {
1954                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1955
1956                 retval = 1;
1957                 DEBC_printk(STp,
1958                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1959                             SRpnt->sense[0], SRpnt->sense[1],
1960                             SRpnt->sense[2], SRpnt->sense[3],
1961                             SRpnt->sense[4], SRpnt->sense[5],
1962                             SRpnt->sense[6], SRpnt->sense[7]);
1963                 if (cmdstatp->have_sense) {
1964
1965                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1966                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1967
1968                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1969                                 /* Compute the residual count */
1970                                 if (cmdstatp->remainder_valid)
1971                                         transfer = (int)cmdstatp->uremainder64;
1972                                 else
1973                                         transfer = 0;
1974                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1975                                         if (STp->block_size == 0)
1976                                                 transfer = bytes;
1977                                         /* Some drives set ILI with MEDIUM ERROR */
1978                                         cmdstatp->flags &= ~SENSE_ILI;
1979                                 }
1980
1981                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1982                                         if (STp->block_size == 0 &&
1983                                             transfer < 0) {
1984                                                 st_printk(KERN_NOTICE, STp,
1985                                                           "Failed to read %d "
1986                                                           "byte block with %d "
1987                                                           "byte transfer.\n",
1988                                                           bytes - transfer,
1989                                                           bytes);
1990                                                 if (STps->drv_block >= 0)
1991                                                         STps->drv_block += 1;
1992                                                 STbp->buffer_bytes = 0;
1993                                                 return (-ENOMEM);
1994                                         } else if (STp->block_size == 0) {
1995                                                 STbp->buffer_bytes = bytes - transfer;
1996                                         } else {
1997                                                 st_release_request(SRpnt);
1998                                                 SRpnt = *aSRpnt = NULL;
1999                                                 if (transfer == blks) { /* We did not get anything, error */
2000                                                         st_printk(KERN_NOTICE, STp,
2001                                                                   "Incorrect "
2002                                                                   "block size.\n");
2003                                                         if (STps->drv_block >= 0)
2004                                                                 STps->drv_block += blks - transfer + 1;
2005                                                         st_int_ioctl(STp, MTBSR, 1);
2006                                                         return (-EIO);
2007                                                 }
2008                                                 /* We have some data, deliver it */
2009                                                 STbp->buffer_bytes = (blks - transfer) *
2010                                                     STp->block_size;
2011                                                 DEBC_printk(STp, "ILI but "
2012                                                             "enough data "
2013                                                             "received %ld "
2014                                                             "%d.\n", count,
2015                                                             STbp->buffer_bytes);
2016                                                 if (STps->drv_block >= 0)
2017                                                         STps->drv_block += 1;
2018                                                 if (st_int_ioctl(STp, MTBSR, 1))
2019                                                         return (-EIO);
2020                                         }
2021                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2022                                         if (STps->eof != ST_FM_HIT)
2023                                                 STps->eof = ST_FM_HIT;
2024                                         else
2025                                                 STps->eof = ST_EOD_2;
2026                                         if (STp->block_size == 0)
2027                                                 STbp->buffer_bytes = 0;
2028                                         else
2029                                                 STbp->buffer_bytes =
2030                                                     bytes - transfer * STp->block_size;
2031                                         DEBC_printk(STp, "EOF detected (%d "
2032                                                     "bytes read).\n",
2033                                                     STbp->buffer_bytes);
2034                                 } else if (cmdstatp->flags & SENSE_EOM) {
2035                                         if (STps->eof == ST_FM)
2036                                                 STps->eof = ST_EOD_1;
2037                                         else
2038                                                 STps->eof = ST_EOM_OK;
2039                                         if (STp->block_size == 0)
2040                                                 STbp->buffer_bytes = bytes - transfer;
2041                                         else
2042                                                 STbp->buffer_bytes =
2043                                                     bytes - transfer * STp->block_size;
2044
2045                                         DEBC_printk(STp, "EOM detected (%d "
2046                                                     "bytes read).\n",
2047                                                     STbp->buffer_bytes);
2048                                 }
2049                         }
2050                         /* end of EOF, EOM, ILI test */
2051                         else {  /* nonzero sense key */
2052                                 DEBC_printk(STp, "Tape error while reading.\n");
2053                                 STps->drv_block = (-1);
2054                                 if (STps->eof == ST_FM &&
2055                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2056                                         DEBC_printk(STp, "Zero returned for "
2057                                                     "first BLANK CHECK "
2058                                                     "after EOF.\n");
2059                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2060                                 } else  /* Some other extended sense code */
2061                                         retval = (-EIO);
2062                         }
2063
2064                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2065                                 STbp->buffer_bytes = 0;
2066                 }
2067                 /* End of extended sense test */
2068                 else {          /* Non-extended sense */
2069                         retval = STbp->syscall_result;
2070                 }
2071
2072         }
2073         /* End of error handling */
2074         else {                  /* Read successful */
2075                 STbp->buffer_bytes = bytes;
2076                 if (STp->sili) /* In fixed block mode residual is always zero here */
2077                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2078         }
2079
2080         if (STps->drv_block >= 0) {
2081                 if (STp->block_size == 0)
2082                         STps->drv_block++;
2083                 else
2084                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2085         }
2086         return retval;
2087 }
2088 \f
2089
2090 /* Read command */
2091 static ssize_t
2092 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2093 {
2094         ssize_t total;
2095         ssize_t retval = 0;
2096         ssize_t i, transfer;
2097         int special, do_dio = 0;
2098         struct st_request *SRpnt = NULL;
2099         struct scsi_tape *STp = filp->private_data;
2100         struct st_modedef *STm;
2101         struct st_partstat *STps;
2102         struct st_buffer *STbp = STp->buffer;
2103
2104         if (mutex_lock_interruptible(&STp->lock))
2105                 return -ERESTARTSYS;
2106
2107         retval = rw_checks(STp, filp, count);
2108         if (retval || count == 0)
2109                 goto out;
2110
2111         STm = &(STp->modes[STp->current_mode]);
2112         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2113                 if (!STm->do_read_ahead) {
2114                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2115                         goto out;
2116                 }
2117                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2118         }
2119
2120         STps = &(STp->ps[STp->partition]);
2121         if (STps->rw == ST_WRITING) {
2122                 retval = flush_buffer(STp, 0);
2123                 if (retval)
2124                         goto out;
2125                 STps->rw = ST_READING;
2126         }
2127         DEB(
2128         if (debugging && STps->eof != ST_NOEOF)
2129                 st_printk(ST_DEB_MSG, STp,
2130                           "EOF/EOM flag up (%d). Bytes %d\n",
2131                           STps->eof, STbp->buffer_bytes);
2132         ) /* end DEB */
2133
2134         retval = setup_buffering(STp, buf, count, 1);
2135         if (retval)
2136                 goto out;
2137         do_dio = STbp->do_dio;
2138
2139         if (STbp->buffer_bytes == 0 &&
2140             STps->eof >= ST_EOD_1) {
2141                 if (STps->eof < ST_EOD) {
2142                         STps->eof += 1;
2143                         retval = 0;
2144                         goto out;
2145                 }
2146                 retval = (-EIO);        /* EOM or Blank Check */
2147                 goto out;
2148         }
2149
2150         if (do_dio) {
2151                 /* Check the buffer writability before any tape movement. Don't alter
2152                    buffer data. */
2153                 if (copy_from_user(&i, buf, 1) != 0 ||
2154                     copy_to_user(buf, &i, 1) != 0 ||
2155                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2156                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2157                         retval = (-EFAULT);
2158                         goto out;
2159                 }
2160         }
2161
2162         STps->rw = ST_READING;
2163
2164
2165         /* Loop until enough data in buffer or a special condition found */
2166         for (total = 0, special = 0; total < count && !special;) {
2167
2168                 /* Get new data if the buffer is empty */
2169                 if (STbp->buffer_bytes == 0) {
2170                         special = read_tape(STp, count - total, &SRpnt);
2171                         if (special < 0) {      /* No need to continue read */
2172                                 retval = special;
2173                                 goto out;
2174                         }
2175                 }
2176
2177                 /* Move the data from driver buffer to user buffer */
2178                 if (STbp->buffer_bytes > 0) {
2179                         DEB(
2180                         if (debugging && STps->eof != ST_NOEOF)
2181                                 st_printk(ST_DEB_MSG, STp,
2182                                           "EOF up (%d). Left %d, needed %d.\n",
2183                                           STps->eof, STbp->buffer_bytes,
2184                                           (int)(count - total));
2185                         ) /* end DEB */
2186                         transfer = STbp->buffer_bytes < count - total ?
2187                             STbp->buffer_bytes : count - total;
2188                         if (!do_dio) {
2189                                 i = from_buffer(STbp, buf, transfer);
2190                                 if (i) {
2191                                         retval = i;
2192                                         goto out;
2193                                 }
2194                         }
2195                         buf += transfer;
2196                         total += transfer;
2197                 }
2198
2199                 if (STp->block_size == 0)
2200                         break;  /* Read only one variable length block */
2201
2202         }                       /* for (total = 0, special = 0;
2203                                    total < count && !special; ) */
2204
2205         /* Change the eof state if no data from tape or buffer */
2206         if (total == 0) {
2207                 if (STps->eof == ST_FM_HIT) {
2208                         STps->eof = ST_FM;
2209                         STps->drv_block = 0;
2210                         if (STps->drv_file >= 0)
2211                                 STps->drv_file++;
2212                 } else if (STps->eof == ST_EOD_1) {
2213                         STps->eof = ST_EOD_2;
2214                         STps->drv_block = 0;
2215                         if (STps->drv_file >= 0)
2216                                 STps->drv_file++;
2217                 } else if (STps->eof == ST_EOD_2)
2218                         STps->eof = ST_EOD;
2219         } else if (STps->eof == ST_FM)
2220                 STps->eof = ST_NOEOF;
2221         retval = total;
2222
2223  out:
2224         if (SRpnt != NULL) {
2225                 st_release_request(SRpnt);
2226                 SRpnt = NULL;
2227         }
2228         if (do_dio) {
2229                 release_buffering(STp, 1);
2230                 STbp->buffer_bytes = 0;
2231         }
2232         mutex_unlock(&STp->lock);
2233
2234         return retval;
2235 }
2236 \f
2237
2238
2239 DEB(
2240 /* Set the driver options */
2241 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2242 {
2243         if (debugging) {
2244                 st_printk(KERN_INFO, STp,
2245                           "Mode %d options: buffer writes: %d, "
2246                           "async writes: %d, read ahead: %d\n",
2247                           STp->current_mode, STm->do_buffer_writes,
2248                           STm->do_async_writes, STm->do_read_ahead);
2249                 st_printk(KERN_INFO, STp,
2250                           "    can bsr: %d, two FMs: %d, "
2251                           "fast mteom: %d, auto lock: %d,\n",
2252                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2253                           STp->do_auto_lock);
2254                 st_printk(KERN_INFO, STp,
2255                           "    defs for wr: %d, no block limits: %d, "
2256                           "partitions: %d, s2 log: %d\n",
2257                           STm->defaults_for_writes, STp->omit_blklims,
2258                           STp->can_partitions, STp->scsi2_logical);
2259                 st_printk(KERN_INFO, STp,
2260                           "    sysv: %d nowait: %d sili: %d "
2261                           "nowait_filemark: %d\n",
2262                           STm->sysv, STp->immediate, STp->sili,
2263                           STp->immediate_filemark);
2264                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2265         }
2266 }
2267         )
2268
2269
2270 static int st_set_options(struct scsi_tape *STp, long options)
2271 {
2272         int value;
2273         long code;
2274         struct st_modedef *STm;
2275         struct cdev *cd0, *cd1;
2276         struct device *d0, *d1;
2277
2278         STm = &(STp->modes[STp->current_mode]);
2279         if (!STm->defined) {
2280                 cd0 = STm->cdevs[0];
2281                 cd1 = STm->cdevs[1];
2282                 d0  = STm->devs[0];
2283                 d1  = STm->devs[1];
2284                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2285                 STm->cdevs[0] = cd0;
2286                 STm->cdevs[1] = cd1;
2287                 STm->devs[0]  = d0;
2288                 STm->devs[1]  = d1;
2289                 modes_defined = 1;
2290                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2291                             STp->current_mode);
2292         }
2293
2294         code = options & MT_ST_OPTIONS;
2295         if (code == MT_ST_BOOLEANS) {
2296                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2297                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2298                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2299                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2300                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2301                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2302                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2303                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2304                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2305                 if ((STp->device)->scsi_level >= SCSI_2)
2306                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2307                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2308                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2309                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2310                 STm->sysv = (options & MT_ST_SYSV) != 0;
2311                 STp->sili = (options & MT_ST_SILI) != 0;
2312                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2313                      st_log_options(STp, STm); )
2314         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2315                 value = (code == MT_ST_SETBOOLEANS);
2316                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2317                         STm->do_buffer_writes = value;
2318                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2319                         STm->do_async_writes = value;
2320                 if ((options & MT_ST_DEF_WRITES) != 0)
2321                         STm->defaults_for_writes = value;
2322                 if ((options & MT_ST_READ_AHEAD) != 0)
2323                         STm->do_read_ahead = value;
2324                 if ((options & MT_ST_TWO_FM) != 0)
2325                         STp->two_fm = value;
2326                 if ((options & MT_ST_FAST_MTEOM) != 0)
2327                         STp->fast_mteom = value;
2328                 if ((options & MT_ST_AUTO_LOCK) != 0)
2329                         STp->do_auto_lock = value;
2330                 if ((options & MT_ST_CAN_BSR) != 0)
2331                         STp->can_bsr = value;
2332                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2333                         STp->omit_blklims = value;
2334                 if ((STp->device)->scsi_level >= SCSI_2 &&
2335                     (options & MT_ST_CAN_PARTITIONS) != 0)
2336                         STp->can_partitions = value;
2337                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2338                         STp->scsi2_logical = value;
2339                 if ((options & MT_ST_NOWAIT) != 0)
2340                         STp->immediate = value;
2341                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2342                         STp->immediate_filemark = value;
2343                 if ((options & MT_ST_SYSV) != 0)
2344                         STm->sysv = value;
2345                 if ((options & MT_ST_SILI) != 0)
2346                         STp->sili = value;
2347                 DEB(
2348                 if ((options & MT_ST_DEBUGGING) != 0)
2349                         debugging = value;
2350                         st_log_options(STp, STm); )
2351         } else if (code == MT_ST_WRITE_THRESHOLD) {
2352                 /* Retained for compatibility */
2353         } else if (code == MT_ST_DEF_BLKSIZE) {
2354                 value = (options & ~MT_ST_OPTIONS);
2355                 if (value == ~MT_ST_OPTIONS) {
2356                         STm->default_blksize = (-1);
2357                         DEBC_printk(STp, "Default block size disabled.\n");
2358                 } else {
2359                         STm->default_blksize = value;
2360                         DEBC_printk(STp,"Default block size set to "
2361                                     "%d bytes.\n", STm->default_blksize);
2362                         if (STp->ready == ST_READY) {
2363                                 STp->blksize_changed = 0;
2364                                 set_mode_densblk(STp, STm);
2365                         }
2366                 }
2367         } else if (code == MT_ST_TIMEOUTS) {
2368                 value = (options & ~MT_ST_OPTIONS);
2369                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2370                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2371                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2372                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2373                 } else {
2374                         blk_queue_rq_timeout(STp->device->request_queue,
2375                                              value * HZ);
2376                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2377                                     value);
2378                 }
2379         } else if (code == MT_ST_SET_CLN) {
2380                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2381                 if (value != 0 &&
2382                         (value < EXTENDED_SENSE_START ||
2383                                 value >= SCSI_SENSE_BUFFERSIZE))
2384                         return (-EINVAL);
2385                 STp->cln_mode = value;
2386                 STp->cln_sense_mask = (options >> 8) & 0xff;
2387                 STp->cln_sense_value = (options >> 16) & 0xff;
2388                 st_printk(KERN_INFO, STp,
2389                           "Cleaning request mode %d, mask %02x, value %02x\n",
2390                           value, STp->cln_sense_mask, STp->cln_sense_value);
2391         } else if (code == MT_ST_DEF_OPTIONS) {
2392                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2393                 value = (options & MT_ST_CLEAR_DEFAULT);
2394                 if (code == MT_ST_DEF_DENSITY) {
2395                         if (value == MT_ST_CLEAR_DEFAULT) {
2396                                 STm->default_density = (-1);
2397                                 DEBC_printk(STp,
2398                                             "Density default disabled.\n");
2399                         } else {
2400                                 STm->default_density = value & 0xff;
2401                                 DEBC_printk(STp, "Density default set to %x\n",
2402                                             STm->default_density);
2403                                 if (STp->ready == ST_READY) {
2404                                         STp->density_changed = 0;
2405                                         set_mode_densblk(STp, STm);
2406                                 }
2407                         }
2408                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2409                         if (value == MT_ST_CLEAR_DEFAULT) {
2410                                 STp->default_drvbuffer = 0xff;
2411                                 DEBC_printk(STp,
2412                                             "Drive buffer default disabled.\n");
2413                         } else {
2414                                 STp->default_drvbuffer = value & 7;
2415                                 DEBC_printk(STp,
2416                                             "Drive buffer default set to %x\n",
2417                                             STp->default_drvbuffer);
2418                                 if (STp->ready == ST_READY)
2419                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2420                         }
2421                 } else if (code == MT_ST_DEF_COMPRESSION) {
2422                         if (value == MT_ST_CLEAR_DEFAULT) {
2423                                 STm->default_compression = ST_DONT_TOUCH;
2424                                 DEBC_printk(STp,
2425                                             "Compression default disabled.\n");
2426                         } else {
2427                                 if ((value & 0xff00) != 0) {
2428                                         STp->c_algo = (value & 0xff00) >> 8;
2429                                         DEBC_printk(STp, "Compression "
2430                                                     "algorithm set to 0x%x.\n",
2431                                                     STp->c_algo);
2432                                 }
2433                                 if ((value & 0xff) != 0xff) {
2434                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2435                                         DEBC_printk(STp, "Compression default "
2436                                                     "set to %x\n",
2437                                                     (value & 1));
2438                                         if (STp->ready == ST_READY) {
2439                                                 STp->compression_changed = 0;
2440                                                 st_compression(STp, (STm->default_compression == ST_YES));
2441                                         }
2442                                 }
2443                         }
2444                 }
2445         } else
2446                 return (-EIO);
2447
2448         return 0;
2449 }
2450 \f
2451 #define MODE_HEADER_LENGTH  4
2452
2453 /* Mode header and page byte offsets */
2454 #define MH_OFF_DATA_LENGTH     0
2455 #define MH_OFF_MEDIUM_TYPE     1
2456 #define MH_OFF_DEV_SPECIFIC    2
2457 #define MH_OFF_BDESCS_LENGTH   3
2458 #define MP_OFF_PAGE_NBR        0
2459 #define MP_OFF_PAGE_LENGTH     1
2460
2461 /* Mode header and page bit masks */
2462 #define MH_BIT_WP              0x80
2463 #define MP_MSK_PAGE_NBR        0x3f
2464
2465 /* Don't return block descriptors */
2466 #define MODE_SENSE_OMIT_BDESCS 0x08
2467
2468 #define MODE_SELECT_PAGE_FORMAT 0x10
2469
2470 /* Read a mode page into the tape buffer. The block descriptors are included
2471    if incl_block_descs is true. The page control is ored to the page number
2472    parameter, if necessary. */
2473 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2474 {
2475         unsigned char cmd[MAX_COMMAND_SIZE];
2476         struct st_request *SRpnt;
2477
2478         memset(cmd, 0, MAX_COMMAND_SIZE);
2479         cmd[0] = MODE_SENSE;
2480         if (omit_block_descs)
2481                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2482         cmd[2] = page;
2483         cmd[4] = 255;
2484
2485         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2486                            STp->device->request_queue->rq_timeout, 0, 1);
2487         if (SRpnt == NULL)
2488                 return (STp->buffer)->syscall_result;
2489
2490         st_release_request(SRpnt);
2491
2492         return STp->buffer->syscall_result;
2493 }
2494
2495
2496 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2497    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2498 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2499 {
2500         int pgo;
2501         unsigned char cmd[MAX_COMMAND_SIZE];
2502         struct st_request *SRpnt;
2503         int timeout;
2504
2505         memset(cmd, 0, MAX_COMMAND_SIZE);
2506         cmd[0] = MODE_SELECT;
2507         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2508         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2509         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2510
2511         /* Clear reserved fields */
2512         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2513         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2514         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2515         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2516
2517         timeout = slow ?
2518                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2519         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2520                            timeout, 0, 1);
2521         if (SRpnt == NULL)
2522                 return (STp->buffer)->syscall_result;
2523
2524         st_release_request(SRpnt);
2525
2526         return STp->buffer->syscall_result;
2527 }
2528
2529
2530 #define COMPRESSION_PAGE        0x0f
2531 #define COMPRESSION_PAGE_LENGTH 16
2532
2533 #define CP_OFF_DCE_DCC          2
2534 #define CP_OFF_C_ALGO           7
2535
2536 #define DCE_MASK  0x80
2537 #define DCC_MASK  0x40
2538 #define RED_MASK  0x60
2539
2540
2541 /* Control the compression with mode page 15. Algorithm not changed if zero.
2542
2543    The block descriptors are read and written because Sony SDT-7000 does not
2544    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2545    Including block descriptors should not cause any harm to other drives. */
2546
2547 static int st_compression(struct scsi_tape * STp, int state)
2548 {
2549         int retval;
2550         int mpoffs;  /* Offset to mode page start */
2551         unsigned char *b_data = (STp->buffer)->b_data;
2552
2553         if (STp->ready != ST_READY)
2554                 return (-EIO);
2555
2556         /* Read the current page contents */
2557         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2558         if (retval) {
2559                 DEBC_printk(STp, "Compression mode page not supported.\n");
2560                 return (-EIO);
2561         }
2562
2563         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2564         DEBC_printk(STp, "Compression state is %d.\n",
2565                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2566
2567         /* Check if compression can be changed */
2568         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2569                 DEBC_printk(STp, "Compression not supported.\n");
2570                 return (-EIO);
2571         }
2572
2573         /* Do the change */
2574         if (state) {
2575                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2576                 if (STp->c_algo != 0)
2577                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2578         }
2579         else {
2580                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2581                 if (STp->c_algo != 0)
2582                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2583         }
2584
2585         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2586         if (retval) {
2587                 DEBC_printk(STp, "Compression change failed.\n");
2588                 return (-EIO);
2589         }
2590         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2591
2592         STp->compression_changed = 1;
2593         return 0;
2594 }
2595
2596
2597 /* Process the load and unload commands (does unload if the load code is zero) */
2598 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2599 {
2600         int retval = (-EIO), timeout;
2601         unsigned char cmd[MAX_COMMAND_SIZE];
2602         struct st_partstat *STps;
2603         struct st_request *SRpnt;
2604
2605         if (STp->ready != ST_READY && !load_code) {
2606                 if (STp->ready == ST_NO_TAPE)
2607                         return (-ENOMEDIUM);
2608                 else
2609                         return (-EIO);
2610         }
2611
2612         memset(cmd, 0, MAX_COMMAND_SIZE);
2613         cmd[0] = START_STOP;
2614         if (load_code)
2615                 cmd[4] |= 1;
2616         /*
2617          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2618          */
2619         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2620             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2621                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2622                             (cmd[4]) ? "" : "un",
2623                             load_code - MT_ST_HPLOADER_OFFSET);
2624                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2625         }
2626         if (STp->immediate) {
2627                 cmd[1] = 1;     /* Don't wait for completion */
2628                 timeout = STp->device->request_queue->rq_timeout;
2629         }
2630         else
2631                 timeout = STp->long_timeout;
2632
2633         DEBC(
2634                 if (!load_code)
2635                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2636                 else
2637                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2638                 );
2639
2640         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2641                            timeout, MAX_RETRIES, 1);
2642         if (!SRpnt)
2643                 return (STp->buffer)->syscall_result;
2644
2645         retval = (STp->buffer)->syscall_result;
2646         st_release_request(SRpnt);
2647
2648         if (!retval) {  /* SCSI command successful */
2649
2650                 if (!load_code) {
2651                         STp->rew_at_close = 0;
2652                         STp->ready = ST_NO_TAPE;
2653                 }
2654                 else {
2655                         STp->rew_at_close = STp->autorew_dev;
2656                         retval = check_tape(STp, filp);
2657                         if (retval > 0)
2658                                 retval = 0;
2659                 }
2660         }
2661         else {
2662                 STps = &(STp->ps[STp->partition]);
2663                 STps->drv_file = STps->drv_block = (-1);
2664         }
2665
2666         return retval;
2667 }
2668 \f
2669 #if DEBUG
2670 #define ST_DEB_FORWARD  0
2671 #define ST_DEB_BACKWARD 1
2672 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2673 {
2674         s32 sc;
2675
2676         if (!debugging)
2677                 return;
2678
2679         sc = sign_extend32(get_unaligned_be24(&cmd[2]), 23);
2680         if (direction)
2681                 sc = -sc;
2682         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2683                   direction ? "backward" : "forward", sc, units);
2684 }
2685 #else
2686 #define ST_DEB_FORWARD  0
2687 #define ST_DEB_BACKWARD 1
2688 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2689 #endif
2690
2691
2692 /* Internal ioctl function */
2693 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2694 {
2695         int timeout;
2696         long ltmp;
2697         int ioctl_result;
2698         int chg_eof = 1;
2699         unsigned char cmd[MAX_COMMAND_SIZE];
2700         struct st_request *SRpnt;
2701         struct st_partstat *STps;
2702         int fileno, blkno, at_sm, undone;
2703         int datalen = 0, direction = DMA_NONE;
2704
2705         WARN_ON(STp->buffer->do_dio != 0);
2706         if (STp->ready != ST_READY) {
2707                 if (STp->ready == ST_NO_TAPE)
2708                         return (-ENOMEDIUM);
2709                 else
2710                         return (-EIO);
2711         }
2712         timeout = STp->long_timeout;
2713         STps = &(STp->ps[STp->partition]);
2714         fileno = STps->drv_file;
2715         blkno = STps->drv_block;
2716         at_sm = STps->at_sm;
2717
2718         memset(cmd, 0, MAX_COMMAND_SIZE);
2719         switch (cmd_in) {
2720         case MTFSFM:
2721                 chg_eof = 0;    /* Changed from the FSF after this */
2722                 fallthrough;
2723         case MTFSF:
2724                 cmd[0] = SPACE;
2725                 cmd[1] = 0x01;  /* Space FileMarks */
2726                 cmd[2] = (arg >> 16);
2727                 cmd[3] = (arg >> 8);
2728                 cmd[4] = arg;
2729                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2730                 if (fileno >= 0)
2731                         fileno += arg;
2732                 blkno = 0;
2733                 at_sm &= (arg == 0);
2734                 break;
2735         case MTBSFM:
2736                 chg_eof = 0;    /* Changed from the FSF after this */
2737                 fallthrough;
2738         case MTBSF:
2739                 cmd[0] = SPACE;
2740                 cmd[1] = 0x01;  /* Space FileMarks */
2741                 ltmp = (-arg);
2742                 cmd[2] = (ltmp >> 16);
2743                 cmd[3] = (ltmp >> 8);
2744                 cmd[4] = ltmp;
2745                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2746                 if (fileno >= 0)
2747                         fileno -= arg;
2748                 blkno = (-1);   /* We can't know the block number */
2749                 at_sm &= (arg == 0);
2750                 break;
2751         case MTFSR:
2752                 cmd[0] = SPACE;
2753                 cmd[1] = 0x00;  /* Space Blocks */
2754                 cmd[2] = (arg >> 16);
2755                 cmd[3] = (arg >> 8);
2756                 cmd[4] = arg;
2757                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2758                 if (blkno >= 0)
2759                         blkno += arg;
2760                 at_sm &= (arg == 0);
2761                 break;
2762         case MTBSR:
2763                 cmd[0] = SPACE;
2764                 cmd[1] = 0x00;  /* Space Blocks */
2765                 ltmp = (-arg);
2766                 cmd[2] = (ltmp >> 16);
2767                 cmd[3] = (ltmp >> 8);
2768                 cmd[4] = ltmp;
2769                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2770                 if (blkno >= 0)
2771                         blkno -= arg;
2772                 at_sm &= (arg == 0);
2773                 break;
2774         case MTFSS:
2775                 cmd[0] = SPACE;
2776                 cmd[1] = 0x04;  /* Space Setmarks */
2777                 cmd[2] = (arg >> 16);
2778                 cmd[3] = (arg >> 8);
2779                 cmd[4] = arg;
2780                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2781                 if (arg != 0) {
2782                         blkno = fileno = (-1);
2783                         at_sm = 1;
2784                 }
2785                 break;
2786         case MTBSS:
2787                 cmd[0] = SPACE;
2788                 cmd[1] = 0x04;  /* Space Setmarks */
2789                 ltmp = (-arg);
2790                 cmd[2] = (ltmp >> 16);
2791                 cmd[3] = (ltmp >> 8);
2792                 cmd[4] = ltmp;
2793                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2794                 if (arg != 0) {
2795                         blkno = fileno = (-1);
2796                         at_sm = 1;
2797                 }
2798                 break;
2799         case MTWEOF:
2800         case MTWEOFI:
2801         case MTWSM:
2802                 if (STp->write_prot)
2803                         return (-EACCES);
2804                 cmd[0] = WRITE_FILEMARKS;
2805                 if (cmd_in == MTWSM)
2806                         cmd[1] = 2;
2807                 if (cmd_in == MTWEOFI ||
2808                     (cmd_in == MTWEOF && STp->immediate_filemark))
2809                         cmd[1] |= 1;
2810                 cmd[2] = (arg >> 16);
2811                 cmd[3] = (arg >> 8);
2812                 cmd[4] = arg;
2813                 timeout = STp->device->request_queue->rq_timeout;
2814                 DEBC(
2815                         if (cmd_in != MTWSM)
2816                                 st_printk(ST_DEB_MSG, STp,
2817                                           "Writing %d filemarks.\n",
2818                                           cmd[2] * 65536 +
2819                                           cmd[3] * 256 +
2820                                           cmd[4]);
2821                         else
2822                                 st_printk(ST_DEB_MSG, STp,
2823                                           "Writing %d setmarks.\n",
2824                                           cmd[2] * 65536 +
2825                                           cmd[3] * 256 +
2826                                           cmd[4]);
2827                 )
2828                 if (fileno >= 0)
2829                         fileno += arg;
2830                 blkno = 0;
2831                 at_sm = (cmd_in == MTWSM);
2832                 break;
2833         case MTREW:
2834                 cmd[0] = REZERO_UNIT;
2835                 if (STp->immediate) {
2836                         cmd[1] = 1;     /* Don't wait for completion */
2837                         timeout = STp->device->request_queue->rq_timeout;
2838                 }
2839                 DEBC_printk(STp, "Rewinding tape.\n");
2840                 fileno = blkno = at_sm = 0;
2841                 break;
2842         case MTNOP:
2843                 DEBC_printk(STp, "No op on tape.\n");
2844                 return 0;       /* Should do something ? */
2845         case MTRETEN:
2846                 cmd[0] = START_STOP;
2847                 if (STp->immediate) {
2848                         cmd[1] = 1;     /* Don't wait for completion */
2849                         timeout = STp->device->request_queue->rq_timeout;
2850                 }
2851                 cmd[4] = 3;
2852                 DEBC_printk(STp, "Retensioning tape.\n");
2853                 fileno = blkno = at_sm = 0;
2854                 break;
2855         case MTEOM:
2856                 if (!STp->fast_mteom) {
2857                         /* space to the end of tape */
2858                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2859                         fileno = STps->drv_file;
2860                         if (STps->eof >= ST_EOD_1)
2861                                 return 0;
2862                         /* The next lines would hide the number of spaced FileMarks
2863                            That's why I inserted the previous lines. I had no luck
2864                            with detecting EOM with FSF, so we go now to EOM.
2865                            Joerg Weule */
2866                 } else
2867                         fileno = (-1);
2868                 cmd[0] = SPACE;
2869                 cmd[1] = 3;
2870                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2871                 blkno = -1;
2872                 at_sm = 0;
2873                 break;
2874         case MTERASE:
2875                 if (STp->write_prot)
2876                         return (-EACCES);
2877                 cmd[0] = ERASE;
2878                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2879                 if (STp->immediate) {
2880                         cmd[1] |= 2;    /* Don't wait for completion */
2881                         timeout = STp->device->request_queue->rq_timeout;
2882                 }
2883                 else
2884                         timeout = STp->long_timeout * 8;
2885
2886                 DEBC_printk(STp, "Erasing tape.\n");
2887                 fileno = blkno = at_sm = 0;
2888                 break;
2889         case MTSETBLK:          /* Set block length */
2890         case MTSETDENSITY:      /* Set tape density */
2891         case MTSETDRVBUFFER:    /* Set drive buffering */
2892         case SET_DENS_AND_BLK:  /* Set density and block size */
2893                 chg_eof = 0;
2894                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2895                         return (-EIO);  /* Not allowed if data in buffer */
2896                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2897                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2898                     STp->max_block > 0 &&
2899                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2900                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2901                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2902                         return (-EINVAL);
2903                 }
2904                 cmd[0] = MODE_SELECT;
2905                 if ((STp->use_pf & USE_PF))
2906                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2907                 cmd[4] = datalen = 12;
2908                 direction = DMA_TO_DEVICE;
2909
2910                 memset((STp->buffer)->b_data, 0, 12);
2911                 if (cmd_in == MTSETDRVBUFFER)
2912                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2913                 else
2914                         (STp->buffer)->b_data[2] =
2915                             STp->drv_buffer << 4;
2916                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2917                 if (cmd_in == MTSETDENSITY) {
2918                         (STp->buffer)->b_data[4] = arg;
2919                         STp->density_changed = 1;       /* At least we tried ;-) */
2920                 } else if (cmd_in == SET_DENS_AND_BLK)
2921                         (STp->buffer)->b_data[4] = arg >> 24;
2922                 else
2923                         (STp->buffer)->b_data[4] = STp->density;
2924                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2925                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2926                         if (cmd_in == MTSETBLK)
2927                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2928                 } else
2929                         ltmp = STp->block_size;
2930                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2931                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2932                 (STp->buffer)->b_data[11] = ltmp;
2933                 timeout = STp->device->request_queue->rq_timeout;
2934                 DEBC(
2935                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2936                                 st_printk(ST_DEB_MSG, STp,
2937                                           "Setting block size to %d bytes.\n",
2938                                           (STp->buffer)->b_data[9] * 65536 +
2939                                           (STp->buffer)->b_data[10] * 256 +
2940                                           (STp->buffer)->b_data[11]);
2941                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2942                                 st_printk(ST_DEB_MSG, STp,
2943                                           "Setting density code to %x.\n",
2944                                           (STp->buffer)->b_data[4]);
2945                         if (cmd_in == MTSETDRVBUFFER)
2946                                 st_printk(ST_DEB_MSG, STp,
2947                                           "Setting drive buffer code to %d.\n",
2948                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2949                 )
2950                 break;
2951         default:
2952                 return (-ENOSYS);
2953         }
2954
2955         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2956                            timeout, MAX_RETRIES, 1);
2957         if (!SRpnt)
2958                 return (STp->buffer)->syscall_result;
2959
2960         ioctl_result = (STp->buffer)->syscall_result;
2961
2962         if (!ioctl_result) {    /* SCSI command successful */
2963                 st_release_request(SRpnt);
2964                 SRpnt = NULL;
2965                 STps->drv_block = blkno;
2966                 STps->drv_file = fileno;
2967                 STps->at_sm = at_sm;
2968
2969                 if (cmd_in == MTBSFM)
2970                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2971                 else if (cmd_in == MTFSFM)
2972                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2973
2974                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2975                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2976                         if (STp->block_size != 0) {
2977                                 (STp->buffer)->buffer_blocks =
2978                                     (STp->buffer)->buffer_size / STp->block_size;
2979                         }
2980                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2981                         if (cmd_in == SET_DENS_AND_BLK)
2982                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2983                 } else if (cmd_in == MTSETDRVBUFFER)
2984                         STp->drv_buffer = (arg & 7);
2985                 else if (cmd_in == MTSETDENSITY)
2986                         STp->density = arg;
2987
2988                 if (cmd_in == MTEOM)
2989                         STps->eof = ST_EOD;
2990                 else if (cmd_in == MTFSF)
2991                         STps->eof = ST_FM;
2992                 else if (chg_eof)
2993                         STps->eof = ST_NOEOF;
2994
2995                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2996                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
2997         } else { /* SCSI command was not completely successful. Don't return
2998                     from this block without releasing the SCSI command block! */
2999                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3000
3001                 if (cmdstatp->flags & SENSE_EOM) {
3002                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3003                             cmd_in != MTBSR && cmd_in != MTBSS)
3004                                 STps->eof = ST_EOM_OK;
3005                         STps->drv_block = 0;
3006                 }
3007
3008                 if (cmdstatp->remainder_valid)
3009                         undone = (int)cmdstatp->uremainder64;
3010                 else
3011                         undone = 0;
3012
3013                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3014                     cmdstatp->have_sense &&
3015                     (cmdstatp->flags & SENSE_EOM)) {
3016                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3017                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3018                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3019                                 STps->eof = ST_NOEOF;
3020                         } else {  /* Writing EOF(s) failed */
3021                                 if (fileno >= 0)
3022                                         fileno -= undone;
3023                                 if (undone < arg)
3024                                         STps->eof = ST_NOEOF;
3025                         }
3026                         STps->drv_file = fileno;
3027                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3028                         if (fileno >= 0)
3029                                 STps->drv_file = fileno - undone;
3030                         else
3031                                 STps->drv_file = fileno;
3032                         STps->drv_block = -1;
3033                         STps->eof = ST_NOEOF;
3034                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3035                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3036                                 undone = (-undone);
3037                         if (STps->drv_file >= 0)
3038                                 STps->drv_file = fileno + undone;
3039                         STps->drv_block = 0;
3040                         STps->eof = ST_NOEOF;
3041                 } else if (cmd_in == MTFSR) {
3042                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3043                                 if (STps->drv_file >= 0)
3044                                         STps->drv_file++;
3045                                 STps->drv_block = 0;
3046                                 STps->eof = ST_FM;
3047                         } else {
3048                                 if (blkno >= undone)
3049                                         STps->drv_block = blkno - undone;
3050                                 else
3051                                         STps->drv_block = (-1);
3052                                 STps->eof = ST_NOEOF;
3053                         }
3054                 } else if (cmd_in == MTBSR) {
3055                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3056                                 STps->drv_file--;
3057                                 STps->drv_block = (-1);
3058                         } else {
3059                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3060                                         undone = (-undone);
3061                                 if (STps->drv_block >= 0)
3062                                         STps->drv_block = blkno + undone;
3063                         }
3064                         STps->eof = ST_NOEOF;
3065                 } else if (cmd_in == MTEOM) {
3066                         STps->drv_file = (-1);
3067                         STps->drv_block = (-1);
3068                         STps->eof = ST_EOD;
3069                 } else if (cmd_in == MTSETBLK ||
3070                            cmd_in == MTSETDENSITY ||
3071                            cmd_in == MTSETDRVBUFFER ||
3072                            cmd_in == SET_DENS_AND_BLK) {
3073                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3074                             !(STp->use_pf & PF_TESTED)) {
3075                                 /* Try the other possible state of Page Format if not
3076                                    already tried */
3077                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3078                                 st_release_request(SRpnt);
3079                                 SRpnt = NULL;
3080                                 return st_int_ioctl(STp, cmd_in, arg);
3081                         }
3082                 } else if (chg_eof)
3083                         STps->eof = ST_NOEOF;
3084
3085                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3086                         STps->eof = ST_EOD;
3087
3088                 st_release_request(SRpnt);
3089                 SRpnt = NULL;
3090         }
3091
3092         return ioctl_result;
3093 }
3094 \f
3095
3096 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3097    structure. */
3098
3099 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3100                         int logical)
3101 {
3102         int result;
3103         unsigned char scmd[MAX_COMMAND_SIZE];
3104         struct st_request *SRpnt;
3105
3106         if (STp->ready != ST_READY)
3107                 return (-EIO);
3108
3109         memset(scmd, 0, MAX_COMMAND_SIZE);
3110         if ((STp->device)->scsi_level < SCSI_2) {
3111                 scmd[0] = QFA_REQUEST_BLOCK;
3112                 scmd[4] = 3;
3113         } else {
3114                 scmd[0] = READ_POSITION;
3115                 if (!logical && !STp->scsi2_logical)
3116                         scmd[1] = 1;
3117         }
3118         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3119                            STp->device->request_queue->rq_timeout,
3120                            MAX_READY_RETRIES, 1);
3121         if (!SRpnt)
3122                 return (STp->buffer)->syscall_result;
3123
3124         if ((STp->buffer)->syscall_result != 0 ||
3125             (STp->device->scsi_level >= SCSI_2 &&
3126              ((STp->buffer)->b_data[0] & 4) != 0)) {
3127                 *block = *partition = 0;
3128                 DEBC_printk(STp, " Can't read tape position.\n");
3129                 result = (-EIO);
3130         } else {
3131                 result = 0;
3132                 if ((STp->device)->scsi_level < SCSI_2) {
3133                         *block = ((STp->buffer)->b_data[0] << 16)
3134                             + ((STp->buffer)->b_data[1] << 8)
3135                             + (STp->buffer)->b_data[2];
3136                         *partition = 0;
3137                 } else {
3138                         *block = ((STp->buffer)->b_data[4] << 24)
3139                             + ((STp->buffer)->b_data[5] << 16)
3140                             + ((STp->buffer)->b_data[6] << 8)
3141                             + (STp->buffer)->b_data[7];
3142                         *partition = (STp->buffer)->b_data[1];
3143                         if (((STp->buffer)->b_data[0] & 0x80) &&
3144                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3145                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3146                 }
3147                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3148                             *block, *partition);
3149         }
3150         st_release_request(SRpnt);
3151         SRpnt = NULL;
3152
3153         return result;
3154 }
3155
3156
3157 /* Set the tape block and partition. Negative partition means that only the
3158    block should be set in vendor specific way. */
3159 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3160                         int logical)
3161 {
3162         struct st_partstat *STps;
3163         int result, p;
3164         unsigned int blk;
3165         int timeout;
3166         unsigned char scmd[MAX_COMMAND_SIZE];
3167         struct st_request *SRpnt;
3168
3169         if (STp->ready != ST_READY)
3170                 return (-EIO);
3171         timeout = STp->long_timeout;
3172         STps = &(STp->ps[STp->partition]);
3173
3174         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3175                     block, partition);
3176         DEB(if (partition < 0)
3177                 return (-EIO); )
3178
3179         /* Update the location at the partition we are leaving */
3180         if ((!STp->can_partitions && partition != 0) ||
3181             partition >= ST_NBR_PARTITIONS)
3182                 return (-EINVAL);
3183         if (partition != STp->partition) {
3184                 if (get_location(STp, &blk, &p, 1))
3185                         STps->last_block_valid = 0;
3186                 else {
3187                         STps->last_block_valid = 1;
3188                         STps->last_block_visited = blk;
3189                         DEBC_printk(STp, "Visited block %d for "
3190                                     "partition %d saved.\n",
3191                                     blk, STp->partition);
3192                 }
3193         }
3194
3195         memset(scmd, 0, MAX_COMMAND_SIZE);
3196         if ((STp->device)->scsi_level < SCSI_2) {
3197                 scmd[0] = QFA_SEEK_BLOCK;
3198                 scmd[2] = (block >> 16);
3199                 scmd[3] = (block >> 8);
3200                 scmd[4] = block;
3201                 scmd[5] = 0;
3202         } else {
3203                 scmd[0] = SEEK_10;
3204                 scmd[3] = (block >> 24);
3205                 scmd[4] = (block >> 16);
3206                 scmd[5] = (block >> 8);
3207                 scmd[6] = block;
3208                 if (!logical && !STp->scsi2_logical)
3209                         scmd[1] = 4;
3210                 if (STp->partition != partition) {
3211                         scmd[1] |= 2;
3212                         scmd[8] = partition;
3213                         DEBC_printk(STp, "Trying to change partition "
3214                                     "from %d to %d\n", STp->partition,
3215                                     partition);
3216                 }
3217         }
3218         if (STp->immediate) {
3219                 scmd[1] |= 1;           /* Don't wait for completion */
3220                 timeout = STp->device->request_queue->rq_timeout;
3221         }
3222
3223         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3224                            timeout, MAX_READY_RETRIES, 1);
3225         if (!SRpnt)
3226                 return (STp->buffer)->syscall_result;
3227
3228         STps->drv_block = STps->drv_file = (-1);
3229         STps->eof = ST_NOEOF;
3230         if ((STp->buffer)->syscall_result != 0) {
3231                 result = (-EIO);
3232                 if (STp->can_partitions &&
3233                     (STp->device)->scsi_level >= SCSI_2 &&
3234                     (p = find_partition(STp)) >= 0)
3235                         STp->partition = p;
3236         } else {
3237                 if (STp->can_partitions) {
3238                         STp->partition = partition;
3239                         STps = &(STp->ps[partition]);
3240                         if (!STps->last_block_valid ||
3241                             STps->last_block_visited != block) {
3242                                 STps->at_sm = 0;
3243                                 STps->rw = ST_IDLE;
3244                         }
3245                 } else
3246                         STps->at_sm = 0;
3247                 if (block == 0)
3248                         STps->drv_block = STps->drv_file = 0;
3249                 result = 0;
3250         }
3251
3252         st_release_request(SRpnt);
3253         SRpnt = NULL;
3254
3255         return result;
3256 }
3257
3258
3259 /* Find the current partition number for the drive status. Called from open and
3260    returns either partition number of negative error code. */
3261 static int find_partition(struct scsi_tape *STp)
3262 {
3263         int i, partition;
3264         unsigned int block;
3265
3266         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3267                 return i;
3268         if (partition >= ST_NBR_PARTITIONS)
3269                 return (-EIO);
3270         return partition;
3271 }
3272
3273
3274 /* Change the partition if necessary */
3275 static int switch_partition(struct scsi_tape *STp)
3276 {
3277         struct st_partstat *STps;
3278
3279         if (STp->partition == STp->new_partition)
3280                 return 0;
3281         STps = &(STp->ps[STp->new_partition]);
3282         if (!STps->last_block_valid)
3283                 STps->last_block_visited = 0;
3284         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3285 }
3286 \f
3287 /* Functions for reading and writing the medium partition mode page. */
3288
3289 #define PART_PAGE   0x11
3290 #define PART_PAGE_FIXED_LENGTH 8
3291
3292 #define PP_OFF_MAX_ADD_PARTS   2
3293 #define PP_OFF_NBR_ADD_PARTS   3
3294 #define PP_OFF_FLAGS           4
3295 #define PP_OFF_PART_UNITS      6
3296 #define PP_OFF_RESERVED        7
3297
3298 #define PP_BIT_IDP             0x20
3299 #define PP_BIT_FDP             0x80
3300 #define PP_MSK_PSUM_MB         0x10
3301 #define PP_MSK_PSUM_UNITS      0x18
3302 #define PP_MSK_POFM            0x04
3303
3304 /* Get the number of partitions on the tape. As a side effect reads the
3305    mode page into the tape buffer. */
3306 static int nbr_partitions(struct scsi_tape *STp)
3307 {
3308         int result;
3309
3310         if (STp->ready != ST_READY)
3311                 return (-EIO);
3312
3313         result = read_mode_page(STp, PART_PAGE, 1);
3314
3315         if (result) {
3316                 DEBC_printk(STp, "Can't read medium partition page.\n");
3317                 result = (-EIO);
3318         } else {
3319                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3320                                               PP_OFF_NBR_ADD_PARTS] + 1;
3321                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3322         }
3323
3324         return result;
3325 }
3326
3327
3328 static int format_medium(struct scsi_tape *STp, int format)
3329 {
3330         int result = 0;
3331         int timeout = STp->long_timeout;
3332         unsigned char scmd[MAX_COMMAND_SIZE];
3333         struct st_request *SRpnt;
3334
3335         memset(scmd, 0, MAX_COMMAND_SIZE);
3336         scmd[0] = FORMAT_UNIT;
3337         scmd[2] = format;
3338         if (STp->immediate) {
3339                 scmd[1] |= 1;           /* Don't wait for completion */
3340                 timeout = STp->device->request_queue->rq_timeout;
3341         }
3342         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3343         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3344                            timeout, MAX_RETRIES, 1);
3345         if (!SRpnt)
3346                 result = STp->buffer->syscall_result;
3347         return result;
3348 }
3349
3350
3351 /* Partition the tape into two partitions if size > 0 or one partition if
3352    size == 0.
3353
3354    The block descriptors are read and written because Sony SDT-7000 does not
3355    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3356
3357    My HP C1533A drive returns only one partition size field. This is used to
3358    set the size of partition 1. There is no size field for the default partition.
3359    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3360    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3361    The following algorithm is used to accommodate both drives: if the number of
3362    partition size fields is greater than the maximum number of additional partitions
3363    in the mode page, the second field is used. Otherwise the first field is used.
3364
3365    For Seagate DDS drives the page length must be 8 when no partitions is defined
3366    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3367    is acceptable also to some other old drives and enforced if the first partition
3368    size field is used for the first additional partition size.
3369
3370    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3371  */
3372 static int partition_tape(struct scsi_tape *STp, int size)
3373 {
3374         int result;
3375         int target_partition;
3376         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3377         int pgo, psd_cnt, psdo;
3378         int psum = PP_MSK_PSUM_MB, units = 0;
3379         unsigned char *bp;
3380
3381         result = read_mode_page(STp, PART_PAGE, 0);
3382         if (result) {
3383                 DEBC_printk(STp, "Can't read partition mode page.\n");
3384                 return result;
3385         }
3386         target_partition = 1;
3387         if (size < 0) {
3388                 target_partition = 0;
3389                 size = -size;
3390         }
3391
3392         /* The mode page is in the buffer. Let's modify it and write it. */
3393         bp = (STp->buffer)->b_data;
3394         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3395         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3396                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3397
3398         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3399
3400         if (scsi3) {
3401                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3402                 if (needs_format && size == 0) {
3403                         /* No need to write the mode page when clearing
3404                          *  partitioning
3405                          */
3406                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3407                         result = format_medium(STp, 0);
3408                         goto out;
3409                 }
3410                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3411                         psd_cnt = 2;
3412                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3413                         /* Use units scaling for large partitions if the device
3414                          * suggests it and no precision lost. Required for IBM
3415                          * TS1140/50 drives that don't support MB units.
3416                          */
3417                         if (size >= 1000 && (size % 1000) == 0) {
3418                                 size /= 1000;
3419                                 psum = PP_MSK_PSUM_UNITS;
3420                                 units = 9; /* GB */
3421                         }
3422                 }
3423                 /* Try it anyway if too large to specify in MB */
3424                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3425                         size /= 1000;
3426                         psum = PP_MSK_PSUM_UNITS;
3427                         units = 9;  /* GB */
3428                 }
3429         }
3430
3431         if (size >= 65535 ||  /* Does not fit into two bytes */
3432             (target_partition == 0 && psd_cnt < 2)) {
3433                 result = -EINVAL;
3434                 goto out;
3435         }
3436
3437         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3438         /* The second condition is for HP DDS which use only one partition size
3439          * descriptor
3440          */
3441         if (target_partition > 0 &&
3442             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3443              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3444                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3445                 psdo += 2;
3446         }
3447         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3448
3449         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3450                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3451                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3452
3453         if (size == 0) {
3454                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3455                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3456                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3457                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3458         } else {
3459                 bp[psdo] = (size >> 8) & 0xff;
3460                 bp[psdo + 1] = size & 0xff;
3461                 if (target_partition == 0)
3462                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3463                 bp[pgo + 3] = 1;
3464                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3465                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3466                 DEBC_printk(STp,
3467                             "Formatting tape with two partitions (%i = %d MB).\n",
3468                             target_partition, units > 0 ? size * 1000 : size);
3469         }
3470         bp[pgo + PP_OFF_PART_UNITS] = 0;
3471         bp[pgo + PP_OFF_RESERVED] = 0;
3472         if (size != 1 || units != 0) {
3473                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3474                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3475                 bp[pgo + PP_OFF_PART_UNITS] = units;
3476         } else
3477                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3478                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3479         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3480
3481         result = write_mode_page(STp, PART_PAGE, 1);
3482
3483         if (!result && needs_format)
3484                 result = format_medium(STp, 1);
3485
3486         if (result) {
3487                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3488                 result = (-EIO);
3489         }
3490
3491 out:
3492         return result;
3493 }
3494 \f
3495
3496
3497 /* The ioctl command */
3498 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3499 {
3500         void __user *p = (void __user *)arg;
3501         int i, cmd_nr, cmd_type, bt;
3502         int retval = 0;
3503         unsigned int blk;
3504         struct scsi_tape *STp = file->private_data;
3505         struct st_modedef *STm;
3506         struct st_partstat *STps;
3507
3508         if (mutex_lock_interruptible(&STp->lock))
3509                 return -ERESTARTSYS;
3510
3511         DEB(
3512         if (debugging && !STp->in_use) {
3513                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3514                 retval = (-EIO);
3515                 goto out;
3516         } ) /* end DEB */
3517
3518         STm = &(STp->modes[STp->current_mode]);
3519         STps = &(STp->ps[STp->partition]);
3520
3521         /*
3522          * If we are in the middle of error recovery, don't let anyone
3523          * else try and use this device.  Also, if error recovery fails, it
3524          * may try and take the device offline, in which case all further
3525          * access to the device is prohibited.
3526          */
3527         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3528                         file->f_flags & O_NDELAY);
3529         if (retval)
3530                 goto out;
3531
3532         cmd_type = _IOC_TYPE(cmd_in);
3533         cmd_nr = _IOC_NR(cmd_in);
3534
3535         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3536                 struct mtop mtc;
3537
3538                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3539                         retval = (-EINVAL);
3540                         goto out;
3541                 }
3542
3543                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3544                 if (i) {
3545                         retval = (-EFAULT);
3546                         goto out;
3547                 }
3548
3549                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3550                         st_printk(KERN_WARNING, STp,
3551                                   "MTSETDRVBUFFER only allowed for root.\n");
3552                         retval = (-EPERM);
3553                         goto out;
3554                 }
3555                 if (!STm->defined &&
3556                     (mtc.mt_op != MTSETDRVBUFFER &&
3557                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3558                         retval = (-ENXIO);
3559                         goto out;
3560                 }
3561
3562                 if (!STp->pos_unknown) {
3563
3564                         if (STps->eof == ST_FM_HIT) {
3565                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3566                                     mtc.mt_op == MTEOM) {
3567                                         mtc.mt_count -= 1;
3568                                         if (STps->drv_file >= 0)
3569                                                 STps->drv_file += 1;
3570                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3571                                         mtc.mt_count += 1;
3572                                         if (STps->drv_file >= 0)
3573                                                 STps->drv_file += 1;
3574                                 }
3575                         }
3576
3577                         if (mtc.mt_op == MTSEEK) {
3578                                 /* Old position must be restored if partition will be
3579                                    changed */
3580                                 i = !STp->can_partitions ||
3581                                     (STp->new_partition != STp->partition);
3582                         } else {
3583                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3584                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3585                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3586                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3587                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3588                                     mtc.mt_op == MTCOMPRESSION;
3589                         }
3590                         i = flush_buffer(STp, i);
3591                         if (i < 0) {
3592                                 retval = i;
3593                                 goto out;
3594                         }
3595                         if (STps->rw == ST_WRITING &&
3596                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3597                              mtc.mt_op == MTSEEK ||
3598                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3599                                 i = st_int_ioctl(STp, MTWEOF, 1);
3600                                 if (i < 0) {
3601                                         retval = i;
3602                                         goto out;
3603                                 }
3604                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3605                                         mtc.mt_count++;
3606                                 STps->rw = ST_IDLE;
3607                              }
3608
3609                 } else {
3610                         /*
3611                          * If there was a bus reset, block further access
3612                          * to this device.  If the user wants to rewind the tape,
3613                          * then reset the flag and allow access again.
3614                          */
3615                         if (mtc.mt_op != MTREW &&
3616                             mtc.mt_op != MTOFFL &&
3617                             mtc.mt_op != MTRETEN &&
3618                             mtc.mt_op != MTERASE &&
3619                             mtc.mt_op != MTSEEK &&
3620                             mtc.mt_op != MTEOM) {
3621                                 retval = (-EIO);
3622                                 goto out;
3623                         }
3624                         reset_state(STp);
3625                         /* remove this when the midlevel properly clears was_reset */
3626                         STp->device->was_reset = 0;
3627                 }
3628
3629                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3630                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3631                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3632                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3633
3634                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3635                         do_door_lock(STp, 0);   /* Ignore result! */
3636
3637                 if (mtc.mt_op == MTSETDRVBUFFER &&
3638                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3639                         retval = st_set_options(STp, mtc.mt_count);
3640                         goto out;
3641                 }
3642
3643                 if (mtc.mt_op == MTSETPART) {
3644                         if (!STp->can_partitions ||
3645                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3646                                 retval = (-EINVAL);
3647                                 goto out;
3648                         }
3649                         if (mtc.mt_count >= STp->nbr_partitions &&
3650                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3651                                 retval = (-EIO);
3652                                 goto out;
3653                         }
3654                         if (mtc.mt_count >= STp->nbr_partitions) {
3655                                 retval = (-EINVAL);
3656                                 goto out;
3657                         }
3658                         STp->new_partition = mtc.mt_count;
3659                         retval = 0;
3660                         goto out;
3661                 }
3662
3663                 if (mtc.mt_op == MTMKPART) {
3664                         if (!STp->can_partitions) {
3665                                 retval = (-EINVAL);
3666                                 goto out;
3667                         }
3668                         i = do_load_unload(STp, file, 1);
3669                         if (i < 0) {
3670                                 retval = i;
3671                                 goto out;
3672                         }
3673                         i = partition_tape(STp, mtc.mt_count);
3674                         if (i < 0) {
3675                                 retval = i;
3676                                 goto out;
3677                         }
3678                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3679                                 STp->ps[i].rw = ST_IDLE;
3680                                 STp->ps[i].at_sm = 0;
3681                                 STp->ps[i].last_block_valid = 0;
3682                         }
3683                         STp->partition = STp->new_partition = 0;
3684                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3685                         STps->drv_block = STps->drv_file = 0;
3686                         retval = 0;
3687                         goto out;
3688                 }
3689
3690                 if (mtc.mt_op == MTSEEK) {
3691                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3692                         if (!STp->can_partitions)
3693                                 STp->ps[0].rw = ST_IDLE;
3694                         retval = i;
3695                         goto out;
3696                 }
3697
3698                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3699                         retval = do_load_unload(STp, file, 0);
3700                         goto out;
3701                 }
3702
3703                 if (mtc.mt_op == MTLOAD) {
3704                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3705                         goto out;
3706                 }
3707
3708                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3709                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3710                         goto out;
3711                 }
3712
3713                 if (STp->can_partitions && STp->ready == ST_READY &&
3714                     (i = switch_partition(STp)) < 0) {
3715                         retval = i;
3716                         goto out;
3717                 }
3718
3719                 if (mtc.mt_op == MTCOMPRESSION)
3720                         retval = st_compression(STp, (mtc.mt_count & 1));
3721                 else
3722                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3723                 goto out;
3724         }
3725         if (!STm->defined) {
3726                 retval = (-ENXIO);
3727                 goto out;
3728         }
3729
3730         if ((i = flush_buffer(STp, 0)) < 0) {
3731                 retval = i;
3732                 goto out;
3733         }
3734         if (STp->can_partitions &&
3735             (i = switch_partition(STp)) < 0) {
3736                 retval = i;
3737                 goto out;
3738         }
3739
3740         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3741                 struct mtget mt_status;
3742
3743                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3744                          retval = (-EINVAL);
3745                          goto out;
3746                 }
3747
3748                 mt_status.mt_type = STp->tape_type;
3749                 mt_status.mt_dsreg =
3750                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3751                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3752                 mt_status.mt_blkno = STps->drv_block;
3753                 mt_status.mt_fileno = STps->drv_file;
3754                 if (STp->block_size != 0) {
3755                         if (STps->rw == ST_WRITING)
3756                                 mt_status.mt_blkno +=
3757                                     (STp->buffer)->buffer_bytes / STp->block_size;
3758                         else if (STps->rw == ST_READING)
3759                                 mt_status.mt_blkno -=
3760                                         ((STp->buffer)->buffer_bytes +
3761                                          STp->block_size - 1) / STp->block_size;
3762                 }
3763
3764                 mt_status.mt_gstat = 0;
3765                 if (STp->drv_write_prot)
3766                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3767                 if (mt_status.mt_blkno == 0) {
3768                         if (mt_status.mt_fileno == 0)
3769                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3770                         else
3771                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3772                 }
3773                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3774                 mt_status.mt_resid = STp->partition;
3775                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3776                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3777                 else if (STps->eof >= ST_EOM_OK)
3778                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3779                 if (STp->density == 1)
3780                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3781                 else if (STp->density == 2)
3782                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3783                 else if (STp->density == 3)
3784                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3785                 if (STp->ready == ST_READY)
3786                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3787                 if (STp->ready == ST_NO_TAPE)
3788                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3789                 if (STps->at_sm)
3790                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3791                 if (STm->do_async_writes ||
3792                     (STm->do_buffer_writes && STp->block_size != 0) ||
3793                     STp->drv_buffer != 0)
3794                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3795                 if (STp->cleaning_req)
3796                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3797
3798                 retval = put_user_mtget(p, &mt_status);
3799                 if (retval)
3800                         goto out;
3801
3802                 STp->recover_reg = 0;           /* Clear after read */
3803                 goto out;
3804         }                       /* End of MTIOCGET */
3805         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3806                 struct mtpos mt_pos;
3807                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3808                          retval = (-EINVAL);
3809                          goto out;
3810                 }
3811                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3812                         retval = i;
3813                         goto out;
3814                 }
3815                 mt_pos.mt_blkno = blk;
3816                 retval = put_user_mtpos(p, &mt_pos);
3817                 goto out;
3818         }
3819         mutex_unlock(&STp->lock);
3820
3821         switch (cmd_in) {
3822         case SG_IO:
3823         case SCSI_IOCTL_SEND_COMMAND:
3824         case CDROM_SEND_PACKET:
3825                 if (!capable(CAP_SYS_RAWIO))
3826                         return -EPERM;
3827                 break;
3828         default:
3829                 break;
3830         }
3831
3832         retval = scsi_ioctl(STp->device, file->f_mode, cmd_in, p);
3833         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) {
3834                 /* unload */
3835                 STp->rew_at_close = 0;
3836                 STp->ready = ST_NO_TAPE;
3837         }
3838         return retval;
3839
3840  out:
3841         mutex_unlock(&STp->lock);
3842         return retval;
3843 }
3844
3845 #ifdef CONFIG_COMPAT
3846 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3847 {
3848         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3849         switch (cmd_in) {
3850         case MTIOCPOS32:
3851                 cmd_in = MTIOCPOS;
3852                 break;
3853         case MTIOCGET32:
3854                 cmd_in = MTIOCGET;
3855                 break;
3856         }
3857
3858         return st_ioctl(file, cmd_in, arg);
3859 }
3860 #endif
3861
3862 \f
3863
3864 /* Try to allocate a new tape buffer. Calling function must not hold
3865    dev_arr_lock. */
3866 static struct st_buffer *new_tape_buffer(int max_sg)
3867 {
3868         struct st_buffer *tb;
3869
3870         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3871         if (!tb) {
3872                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3873                 return NULL;
3874         }
3875         tb->frp_segs = 0;
3876         tb->use_sg = max_sg;
3877         tb->buffer_size = 0;
3878
3879         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3880                                      GFP_KERNEL);
3881         if (!tb->reserved_pages) {
3882                 kfree(tb);
3883                 return NULL;
3884         }
3885
3886         return tb;
3887 }
3888
3889
3890 /* Try to allocate enough space in the tape buffer */
3891 #define ST_MAX_ORDER 6
3892
3893 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size)
3894 {
3895         int segs, max_segs, b_size, order, got;
3896         gfp_t priority;
3897
3898         if (new_size <= STbuffer->buffer_size)
3899                 return 1;
3900
3901         if (STbuffer->buffer_size <= PAGE_SIZE)
3902                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3903
3904         max_segs = STbuffer->use_sg;
3905
3906         priority = GFP_KERNEL | __GFP_NOWARN;
3907
3908         if (STbuffer->cleared)
3909                 priority |= __GFP_ZERO;
3910
3911         if (STbuffer->frp_segs) {
3912                 order = STbuffer->reserved_page_order;
3913                 b_size = PAGE_SIZE << order;
3914         } else {
3915                 for (b_size = PAGE_SIZE, order = 0;
3916                      order < ST_MAX_ORDER &&
3917                              max_segs * (PAGE_SIZE << order) < new_size;
3918                      order++, b_size *= 2)
3919                         ;  /* empty */
3920                 STbuffer->reserved_page_order = order;
3921         }
3922         if (max_segs * (PAGE_SIZE << order) < new_size) {
3923                 if (order == ST_MAX_ORDER)
3924                         return 0;
3925                 normalize_buffer(STbuffer);
3926                 return enlarge_buffer(STbuffer, new_size);
3927         }
3928
3929         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3930              segs < max_segs && got < new_size;) {
3931                 struct page *page;
3932
3933                 page = alloc_pages(priority, order);
3934                 if (!page) {
3935                         DEB(STbuffer->buffer_size = got);
3936                         normalize_buffer(STbuffer);
3937                         return 0;
3938                 }
3939
3940                 STbuffer->frp_segs += 1;
3941                 got += b_size;
3942                 STbuffer->buffer_size = got;
3943                 STbuffer->reserved_pages[segs] = page;
3944                 segs++;
3945         }
3946         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3947
3948         return 1;
3949 }
3950
3951
3952 /* Make sure that no data from previous user is in the internal buffer */
3953 static void clear_buffer(struct st_buffer * st_bp)
3954 {
3955         int i;
3956
3957         for (i=0; i < st_bp->frp_segs; i++)
3958                 memset(page_address(st_bp->reserved_pages[i]), 0,
3959                        PAGE_SIZE << st_bp->reserved_page_order);
3960         st_bp->cleared = 1;
3961 }
3962
3963
3964 /* Release the extra buffer */
3965 static void normalize_buffer(struct st_buffer * STbuffer)
3966 {
3967         int i, order = STbuffer->reserved_page_order;
3968
3969         for (i = 0; i < STbuffer->frp_segs; i++) {
3970                 __free_pages(STbuffer->reserved_pages[i], order);
3971                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3972         }
3973         STbuffer->frp_segs = 0;
3974         STbuffer->sg_segs = 0;
3975         STbuffer->reserved_page_order = 0;
3976         STbuffer->map_data.offset = 0;
3977 }
3978
3979
3980 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3981    negative error code. */
3982 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3983 {
3984         int i, cnt, res, offset;
3985         int length = PAGE_SIZE << st_bp->reserved_page_order;
3986
3987         for (i = 0, offset = st_bp->buffer_bytes;
3988              i < st_bp->frp_segs && offset >= length; i++)
3989                 offset -= length;
3990         if (i == st_bp->frp_segs) {     /* Should never happen */
3991                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3992                 return (-EIO);
3993         }
3994         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3995                 struct page *page = st_bp->reserved_pages[i];
3996                 cnt = length - offset < do_count ? length - offset : do_count;
3997                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
3998                 if (res)
3999                         return (-EFAULT);
4000                 do_count -= cnt;
4001                 st_bp->buffer_bytes += cnt;
4002                 ubp += cnt;
4003                 offset = 0;
4004         }
4005         if (do_count) /* Should never happen */
4006                 return (-EIO);
4007
4008         return 0;
4009 }
4010
4011
4012 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4013    negative error code. */
4014 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4015 {
4016         int i, cnt, res, offset;
4017         int length = PAGE_SIZE << st_bp->reserved_page_order;
4018
4019         for (i = 0, offset = st_bp->read_pointer;
4020              i < st_bp->frp_segs && offset >= length; i++)
4021                 offset -= length;
4022         if (i == st_bp->frp_segs) {     /* Should never happen */
4023                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4024                 return (-EIO);
4025         }
4026         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4027                 struct page *page = st_bp->reserved_pages[i];
4028                 cnt = length - offset < do_count ? length - offset : do_count;
4029                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4030                 if (res)
4031                         return (-EFAULT);
4032                 do_count -= cnt;
4033                 st_bp->buffer_bytes -= cnt;
4034                 st_bp->read_pointer += cnt;
4035                 ubp += cnt;
4036                 offset = 0;
4037         }
4038         if (do_count) /* Should never happen */
4039                 return (-EIO);
4040
4041         return 0;
4042 }
4043
4044
4045 /* Move data towards start of buffer */
4046 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4047 {
4048         int src_seg, dst_seg, src_offset = 0, dst_offset;
4049         int count, total;
4050         int length = PAGE_SIZE << st_bp->reserved_page_order;
4051
4052         if (offset == 0)
4053                 return;
4054
4055         total=st_bp->buffer_bytes - offset;
4056         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4057                 src_offset = offset;
4058                 if (src_offset < length)
4059                         break;
4060                 offset -= length;
4061         }
4062
4063         st_bp->buffer_bytes = st_bp->read_pointer = total;
4064         for (dst_seg=dst_offset=0; total > 0; ) {
4065                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4066                 struct page *spage = st_bp->reserved_pages[src_seg];
4067
4068                 count = min(length - dst_offset, length - src_offset);
4069                 memmove(page_address(dpage) + dst_offset,
4070                         page_address(spage) + src_offset, count);
4071                 src_offset += count;
4072                 if (src_offset >= length) {
4073                         src_seg++;
4074                         src_offset = 0;
4075                 }
4076                 dst_offset += count;
4077                 if (dst_offset >= length) {
4078                         dst_seg++;
4079                         dst_offset = 0;
4080                 }
4081                 total -= count;
4082         }
4083 }
4084
4085 /* Validate the options from command line or module parameters */
4086 static void validate_options(void)
4087 {
4088         if (buffer_kbs > 0)
4089                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4090         if (max_sg_segs >= ST_FIRST_SG)
4091                 st_max_sg_segs = max_sg_segs;
4092 }
4093
4094 #ifndef MODULE
4095 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4096  */
4097 static int __init st_setup(char *str)
4098 {
4099         int i, len, ints[5];
4100         char *stp;
4101
4102         stp = get_options(str, ARRAY_SIZE(ints), ints);
4103
4104         if (ints[0] > 0) {
4105                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4106                         if (parms[i].val)
4107                                 *parms[i].val = ints[i + 1];
4108         } else {
4109                 while (stp != NULL) {
4110                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4111                                 len = strlen(parms[i].name);
4112                                 if (!strncmp(stp, parms[i].name, len) &&
4113                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4114                                         if (parms[i].val)
4115                                                 *parms[i].val =
4116                                                         simple_strtoul(stp + len + 1, NULL, 0);
4117                                         else
4118                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4119                                                        parms[i].name);
4120                                         break;
4121                                 }
4122                         }
4123                         if (i >= ARRAY_SIZE(parms))
4124                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4125                                         stp);
4126                         stp = strchr(stp, ',');
4127                         if (stp)
4128                                 stp++;
4129                 }
4130         }
4131
4132         validate_options();
4133
4134         return 1;
4135 }
4136
4137 __setup("st=", st_setup);
4138
4139 #endif
4140
4141 static const struct file_operations st_fops =
4142 {
4143         .owner =        THIS_MODULE,
4144         .read =         st_read,
4145         .write =        st_write,
4146         .unlocked_ioctl = st_ioctl,
4147 #ifdef CONFIG_COMPAT
4148         .compat_ioctl = st_compat_ioctl,
4149 #endif
4150         .open =         st_open,
4151         .flush =        st_flush,
4152         .release =      st_release,
4153         .llseek =       noop_llseek,
4154 };
4155
4156 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4157 {
4158         int i, error;
4159         dev_t cdev_devno;
4160         struct cdev *cdev;
4161         struct device *dev;
4162         struct st_modedef *STm = &(tape->modes[mode]);
4163         char name[10];
4164         int dev_num = tape->index;
4165
4166         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4167
4168         cdev = cdev_alloc();
4169         if (!cdev) {
4170                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4171                 error = -ENOMEM;
4172                 goto out;
4173         }
4174         cdev->owner = THIS_MODULE;
4175         cdev->ops = &st_fops;
4176         STm->cdevs[rew] = cdev;
4177
4178         error = cdev_add(cdev, cdev_devno, 1);
4179         if (error) {
4180                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4181                        rew ? "non" : "auto", mode);
4182                 pr_err("st%d: Device not attached.\n", dev_num);
4183                 goto out_free;
4184         }
4185
4186         i = mode << (4 - ST_NBR_MODE_BITS);
4187         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4188                  tape->name, st_formats[i]);
4189
4190         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4191                             cdev_devno, &tape->modes[mode], "%s", name);
4192         if (IS_ERR(dev)) {
4193                 pr_err("st%d: device_create failed\n", dev_num);
4194                 error = PTR_ERR(dev);
4195                 goto out_free;
4196         }
4197
4198         STm->devs[rew] = dev;
4199
4200         return 0;
4201 out_free:
4202         cdev_del(STm->cdevs[rew]);
4203 out:
4204         STm->cdevs[rew] = NULL;
4205         STm->devs[rew] = NULL;
4206         return error;
4207 }
4208
4209 static int create_cdevs(struct scsi_tape *tape)
4210 {
4211         int mode, error;
4212         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4213                 error = create_one_cdev(tape, mode, 0);
4214                 if (error)
4215                         return error;
4216                 error = create_one_cdev(tape, mode, 1);
4217                 if (error)
4218                         return error;
4219         }
4220
4221         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4222                                  &tape->modes[0].devs[0]->kobj, "tape");
4223 }
4224
4225 static void remove_cdevs(struct scsi_tape *tape)
4226 {
4227         int mode, rew;
4228         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4229         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4230                 struct st_modedef *STm = &(tape->modes[mode]);
4231                 for (rew = 0; rew < 2; rew++) {
4232                         if (STm->cdevs[rew])
4233                                 cdev_del(STm->cdevs[rew]);
4234                         if (STm->devs[rew])
4235                                 device_unregister(STm->devs[rew]);
4236                 }
4237         }
4238 }
4239
4240 static int st_probe(struct device *dev)
4241 {
4242         struct scsi_device *SDp = to_scsi_device(dev);
4243         struct scsi_tape *tpnt = NULL;
4244         struct st_modedef *STm;
4245         struct st_partstat *STps;
4246         struct st_buffer *buffer;
4247         int i, error;
4248         char *stp;
4249
4250         if (SDp->type != TYPE_TAPE)
4251                 return -ENODEV;
4252         if ((stp = st_incompatible(SDp))) {
4253                 sdev_printk(KERN_INFO, SDp,
4254                             "OnStream tapes are no longer supported;\n");
4255                 sdev_printk(KERN_INFO, SDp,
4256                             "please mail to linux-scsi@vger.kernel.org.\n");
4257                 return -ENODEV;
4258         }
4259
4260         scsi_autopm_get_device(SDp);
4261         i = queue_max_segments(SDp->request_queue);
4262         if (st_max_sg_segs < i)
4263                 i = st_max_sg_segs;
4264         buffer = new_tape_buffer(i);
4265         if (buffer == NULL) {
4266                 sdev_printk(KERN_ERR, SDp,
4267                             "st: Can't allocate new tape buffer. "
4268                             "Device not attached.\n");
4269                 goto out;
4270         }
4271
4272         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4273         if (tpnt == NULL) {
4274                 sdev_printk(KERN_ERR, SDp,
4275                             "st: Can't allocate device descriptor.\n");
4276                 goto out_buffer_free;
4277         }
4278         kref_init(&tpnt->kref);
4279
4280         tpnt->device = SDp;
4281         if (SDp->scsi_level <= 2)
4282                 tpnt->tape_type = MT_ISSCSI1;
4283         else
4284                 tpnt->tape_type = MT_ISSCSI2;
4285
4286         tpnt->buffer = buffer;
4287         tpnt->buffer->last_SRpnt = NULL;
4288
4289         tpnt->inited = 0;
4290         tpnt->dirty = 0;
4291         tpnt->in_use = 0;
4292         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4293         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4294         tpnt->density = 0;
4295         tpnt->do_auto_lock = ST_AUTO_LOCK;
4296         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4297         tpnt->can_partitions = 0;
4298         tpnt->two_fm = ST_TWO_FM;
4299         tpnt->fast_mteom = ST_FAST_MTEOM;
4300         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4301         tpnt->sili = ST_SILI;
4302         tpnt->immediate = ST_NOWAIT;
4303         tpnt->immediate_filemark = 0;
4304         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4305         tpnt->partition = 0;
4306         tpnt->new_partition = 0;
4307         tpnt->nbr_partitions = 0;
4308         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4309         tpnt->long_timeout = ST_LONG_TIMEOUT;
4310         tpnt->try_dio = try_direct_io;
4311
4312         for (i = 0; i < ST_NBR_MODES; i++) {
4313                 STm = &(tpnt->modes[i]);
4314                 STm->defined = 0;
4315                 STm->sysv = ST_SYSV;
4316                 STm->defaults_for_writes = 0;
4317                 STm->do_async_writes = ST_ASYNC_WRITES;
4318                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4319                 STm->do_read_ahead = ST_READ_AHEAD;
4320                 STm->default_compression = ST_DONT_TOUCH;
4321                 STm->default_blksize = (-1);    /* No forced size */
4322                 STm->default_density = (-1);    /* No forced density */
4323                 STm->tape = tpnt;
4324         }
4325
4326         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4327                 STps = &(tpnt->ps[i]);
4328                 STps->rw = ST_IDLE;
4329                 STps->eof = ST_NOEOF;
4330                 STps->at_sm = 0;
4331                 STps->last_block_valid = 0;
4332                 STps->drv_block = (-1);
4333                 STps->drv_file = (-1);
4334         }
4335
4336         tpnt->current_mode = 0;
4337         tpnt->modes[0].defined = 1;
4338
4339         tpnt->density_changed = tpnt->compression_changed =
4340             tpnt->blksize_changed = 0;
4341         mutex_init(&tpnt->lock);
4342
4343         idr_preload(GFP_KERNEL);
4344         spin_lock(&st_index_lock);
4345         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4346         spin_unlock(&st_index_lock);
4347         idr_preload_end();
4348         if (error < 0) {
4349                 pr_warn("st: idr allocation failed: %d\n", error);
4350                 goto out_free_tape;
4351         }
4352         tpnt->index = error;
4353         sprintf(tpnt->name, "st%d", tpnt->index);
4354         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4355         if (tpnt->stats == NULL) {
4356                 sdev_printk(KERN_ERR, SDp,
4357                             "st: Can't allocate statistics.\n");
4358                 goto out_idr_remove;
4359         }
4360
4361         dev_set_drvdata(dev, tpnt);
4362
4363
4364         error = create_cdevs(tpnt);
4365         if (error)
4366                 goto out_remove_devs;
4367         scsi_autopm_put_device(SDp);
4368
4369         sdev_printk(KERN_NOTICE, SDp,
4370                     "Attached scsi tape %s\n", tpnt->name);
4371         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4372                     tpnt->name, tpnt->try_dio ? "yes" : "no",
4373                     queue_dma_alignment(SDp->request_queue) + 1);
4374
4375         return 0;
4376
4377 out_remove_devs:
4378         remove_cdevs(tpnt);
4379         kfree(tpnt->stats);
4380 out_idr_remove:
4381         spin_lock(&st_index_lock);
4382         idr_remove(&st_index_idr, tpnt->index);
4383         spin_unlock(&st_index_lock);
4384 out_free_tape:
4385         kfree(tpnt);
4386 out_buffer_free:
4387         kfree(buffer);
4388 out:
4389         scsi_autopm_put_device(SDp);
4390         return -ENODEV;
4391 };
4392
4393
4394 static int st_remove(struct device *dev)
4395 {
4396         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4397         int index = tpnt->index;
4398
4399         scsi_autopm_get_device(to_scsi_device(dev));
4400         remove_cdevs(tpnt);
4401
4402         mutex_lock(&st_ref_mutex);
4403         kref_put(&tpnt->kref, scsi_tape_release);
4404         mutex_unlock(&st_ref_mutex);
4405         spin_lock(&st_index_lock);
4406         idr_remove(&st_index_idr, index);
4407         spin_unlock(&st_index_lock);
4408         return 0;
4409 }
4410
4411 /**
4412  *      scsi_tape_release - Called to free the Scsi_Tape structure
4413  *      @kref: pointer to embedded kref
4414  *
4415  *      st_ref_mutex must be held entering this routine.  Because it is
4416  *      called on last put, you should always use the scsi_tape_get()
4417  *      scsi_tape_put() helpers which manipulate the semaphore directly
4418  *      and never do a direct kref_put().
4419  **/
4420 static void scsi_tape_release(struct kref *kref)
4421 {
4422         struct scsi_tape *tpnt = to_scsi_tape(kref);
4423
4424         tpnt->device = NULL;
4425
4426         if (tpnt->buffer) {
4427                 normalize_buffer(tpnt->buffer);
4428                 kfree(tpnt->buffer->reserved_pages);
4429                 kfree(tpnt->buffer);
4430         }
4431
4432         kfree(tpnt->stats);
4433         kfree(tpnt);
4434         return;
4435 }
4436
4437 static struct class st_sysfs_class = {
4438         .name = "scsi_tape",
4439         .dev_groups = st_dev_groups,
4440 };
4441
4442 static int __init init_st(void)
4443 {
4444         int err;
4445
4446         validate_options();
4447
4448         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4449                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4450
4451         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4452         if (debugging) {
4453                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4454                         debugging);
4455         }
4456
4457         err = class_register(&st_sysfs_class);
4458         if (err) {
4459                 pr_err("Unable register sysfs class for SCSI tapes\n");
4460                 return err;
4461         }
4462
4463         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4464                                      ST_MAX_TAPE_ENTRIES, "st");
4465         if (err) {
4466                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4467                        SCSI_TAPE_MAJOR);
4468                 goto err_class;
4469         }
4470
4471         err = scsi_register_driver(&st_template.gendrv);
4472         if (err)
4473                 goto err_chrdev;
4474
4475         return 0;
4476
4477 err_chrdev:
4478         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4479                                  ST_MAX_TAPE_ENTRIES);
4480 err_class:
4481         class_unregister(&st_sysfs_class);
4482         return err;
4483 }
4484
4485 static void __exit exit_st(void)
4486 {
4487         scsi_unregister_driver(&st_template.gendrv);
4488         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4489                                  ST_MAX_TAPE_ENTRIES);
4490         class_unregister(&st_sysfs_class);
4491         idr_destroy(&st_index_idr);
4492         printk(KERN_INFO "st: Unloaded.\n");
4493 }
4494
4495 module_init(init_st);
4496 module_exit(exit_st);
4497
4498
4499 /* The sysfs driver interface. Read-only at the moment */
4500 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4501 {
4502         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4503 }
4504 static DRIVER_ATTR_RO(try_direct_io);
4505
4506 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4507 {
4508         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4509 }
4510 static DRIVER_ATTR_RO(fixed_buffer_size);
4511
4512 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4513 {
4514         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4515 }
4516 static DRIVER_ATTR_RO(max_sg_segs);
4517
4518 static ssize_t version_show(struct device_driver *ddd, char *buf)
4519 {
4520         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4521 }
4522 static DRIVER_ATTR_RO(version);
4523
4524 #if DEBUG
4525 static ssize_t debug_flag_store(struct device_driver *ddp,
4526         const char *buf, size_t count)
4527 {
4528 /* We only care what the first byte of the data is the rest is unused.
4529  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4530  * other values have -EINVAL returned if they are passed in.
4531  */
4532         if (count > 0) {
4533                 if (buf[0] == '0') {
4534                         debugging = NO_DEBUG;
4535                         return count;
4536                 } else if (buf[0] == '1') {
4537                         debugging = 1;
4538                         return count;
4539                 }
4540         }
4541         return -EINVAL;
4542 }
4543
4544 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4545 {
4546         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4547 }
4548 static DRIVER_ATTR_RW(debug_flag);
4549 #endif
4550
4551 static struct attribute *st_drv_attrs[] = {
4552         &driver_attr_try_direct_io.attr,
4553         &driver_attr_fixed_buffer_size.attr,
4554         &driver_attr_max_sg_segs.attr,
4555         &driver_attr_version.attr,
4556 #if DEBUG
4557         &driver_attr_debug_flag.attr,
4558 #endif
4559         NULL,
4560 };
4561 ATTRIBUTE_GROUPS(st_drv);
4562
4563 /* The sysfs simple class interface */
4564 static ssize_t
4565 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4566 {
4567         struct st_modedef *STm = dev_get_drvdata(dev);
4568         ssize_t l = 0;
4569
4570         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4571         return l;
4572 }
4573 static DEVICE_ATTR_RO(defined);
4574
4575 static ssize_t
4576 default_blksize_show(struct device *dev, struct device_attribute *attr,
4577                      char *buf)
4578 {
4579         struct st_modedef *STm = dev_get_drvdata(dev);
4580         ssize_t l = 0;
4581
4582         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4583         return l;
4584 }
4585 static DEVICE_ATTR_RO(default_blksize);
4586
4587 static ssize_t
4588 default_density_show(struct device *dev, struct device_attribute *attr,
4589                      char *buf)
4590 {
4591         struct st_modedef *STm = dev_get_drvdata(dev);
4592         ssize_t l = 0;
4593         char *fmt;
4594
4595         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4596         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4597         return l;
4598 }
4599 static DEVICE_ATTR_RO(default_density);
4600
4601 static ssize_t
4602 default_compression_show(struct device *dev, struct device_attribute *attr,
4603                          char *buf)
4604 {
4605         struct st_modedef *STm = dev_get_drvdata(dev);
4606         ssize_t l = 0;
4607
4608         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4609         return l;
4610 }
4611 static DEVICE_ATTR_RO(default_compression);
4612
4613 static ssize_t
4614 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4615 {
4616         struct st_modedef *STm = dev_get_drvdata(dev);
4617         struct scsi_tape *STp = STm->tape;
4618         int options;
4619         ssize_t l = 0;
4620
4621         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4622         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4623         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4624         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4625         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4626         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4627         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4628         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4629         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4630         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4631         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4632         options |= STm->sysv ? MT_ST_SYSV : 0;
4633         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4634         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4635         options |= STp->sili ? MT_ST_SILI : 0;
4636
4637         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4638         return l;
4639 }
4640 static DEVICE_ATTR_RO(options);
4641
4642 /* Support for tape stats */
4643
4644 /**
4645  * read_cnt_show - return read count - count of reads made from tape drive
4646  * @dev: struct device
4647  * @attr: attribute structure
4648  * @buf: buffer to return formatted data in
4649  */
4650 static ssize_t read_cnt_show(struct device *dev,
4651         struct device_attribute *attr, char *buf)
4652 {
4653         struct st_modedef *STm = dev_get_drvdata(dev);
4654
4655         return sprintf(buf, "%lld",
4656                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4657 }
4658 static DEVICE_ATTR_RO(read_cnt);
4659
4660 /**
4661  * read_byte_cnt_show - return read byte count - tape drives
4662  * may use blocks less than 512 bytes this gives the raw byte count of
4663  * of data read from the tape drive.
4664  * @dev: struct device
4665  * @attr: attribute structure
4666  * @buf: buffer to return formatted data in
4667  */
4668 static ssize_t read_byte_cnt_show(struct device *dev,
4669         struct device_attribute *attr, char *buf)
4670 {
4671         struct st_modedef *STm = dev_get_drvdata(dev);
4672
4673         return sprintf(buf, "%lld",
4674                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4675 }
4676 static DEVICE_ATTR_RO(read_byte_cnt);
4677
4678 /**
4679  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4680  * @dev: struct device
4681  * @attr: attribute structure
4682  * @buf: buffer to return formatted data in
4683  */
4684 static ssize_t read_ns_show(struct device *dev,
4685         struct device_attribute *attr, char *buf)
4686 {
4687         struct st_modedef *STm = dev_get_drvdata(dev);
4688
4689         return sprintf(buf, "%lld",
4690                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4691 }
4692 static DEVICE_ATTR_RO(read_ns);
4693
4694 /**
4695  * write_cnt_show - write count - number of user calls
4696  * to write(2) that have written data to tape.
4697  * @dev: struct device
4698  * @attr: attribute structure
4699  * @buf: buffer to return formatted data in
4700  */
4701 static ssize_t write_cnt_show(struct device *dev,
4702         struct device_attribute *attr, char *buf)
4703 {
4704         struct st_modedef *STm = dev_get_drvdata(dev);
4705
4706         return sprintf(buf, "%lld",
4707                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4708 }
4709 static DEVICE_ATTR_RO(write_cnt);
4710
4711 /**
4712  * write_byte_cnt_show - write byte count - raw count of
4713  * bytes written to tape.
4714  * @dev: struct device
4715  * @attr: attribute structure
4716  * @buf: buffer to return formatted data in
4717  */
4718 static ssize_t write_byte_cnt_show(struct device *dev,
4719         struct device_attribute *attr, char *buf)
4720 {
4721         struct st_modedef *STm = dev_get_drvdata(dev);
4722
4723         return sprintf(buf, "%lld",
4724                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4725 }
4726 static DEVICE_ATTR_RO(write_byte_cnt);
4727
4728 /**
4729  * write_ns_show - write ns - number of nanoseconds waiting on write
4730  * requests to complete.
4731  * @dev: struct device
4732  * @attr: attribute structure
4733  * @buf: buffer to return formatted data in
4734  */
4735 static ssize_t write_ns_show(struct device *dev,
4736         struct device_attribute *attr, char *buf)
4737 {
4738         struct st_modedef *STm = dev_get_drvdata(dev);
4739
4740         return sprintf(buf, "%lld",
4741                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4742 }
4743 static DEVICE_ATTR_RO(write_ns);
4744
4745 /**
4746  * in_flight_show - number of I/Os currently in flight -
4747  * in most cases this will be either 0 or 1. It may be higher if someone
4748  * has also issued other SCSI commands such as via an ioctl.
4749  * @dev: struct device
4750  * @attr: attribute structure
4751  * @buf: buffer to return formatted data in
4752  */
4753 static ssize_t in_flight_show(struct device *dev,
4754         struct device_attribute *attr, char *buf)
4755 {
4756         struct st_modedef *STm = dev_get_drvdata(dev);
4757
4758         return sprintf(buf, "%lld",
4759                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4760 }
4761 static DEVICE_ATTR_RO(in_flight);
4762
4763 /**
4764  * io_ns_show - io wait ns - this is the number of ns spent
4765  * waiting on all I/O to complete. This includes tape movement commands
4766  * such as rewinding, seeking to end of file or tape, it also includes
4767  * read and write. To determine the time spent on tape movement
4768  * subtract the read and write ns from this value.
4769  * @dev: struct device
4770  * @attr: attribute structure
4771  * @buf: buffer to return formatted data in
4772  */
4773 static ssize_t io_ns_show(struct device *dev,
4774         struct device_attribute *attr, char *buf)
4775 {
4776         struct st_modedef *STm = dev_get_drvdata(dev);
4777
4778         return sprintf(buf, "%lld",
4779                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4780 }
4781 static DEVICE_ATTR_RO(io_ns);
4782
4783 /**
4784  * other_cnt_show - other io count - this is the number of
4785  * I/O requests other than read and write requests.
4786  * Typically these are tape movement requests but will include driver
4787  * tape movement. This includes only requests issued by the st driver.
4788  * @dev: struct device
4789  * @attr: attribute structure
4790  * @buf: buffer to return formatted data in
4791  */
4792 static ssize_t other_cnt_show(struct device *dev,
4793         struct device_attribute *attr, char *buf)
4794 {
4795         struct st_modedef *STm = dev_get_drvdata(dev);
4796
4797         return sprintf(buf, "%lld",
4798                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4799 }
4800 static DEVICE_ATTR_RO(other_cnt);
4801
4802 /**
4803  * resid_cnt_show - A count of the number of times we get a residual
4804  * count - this should indicate someone issuing reads larger than the
4805  * block size on tape.
4806  * @dev: struct device
4807  * @attr: attribute structure
4808  * @buf: buffer to return formatted data in
4809  */
4810 static ssize_t resid_cnt_show(struct device *dev,
4811         struct device_attribute *attr, char *buf)
4812 {
4813         struct st_modedef *STm = dev_get_drvdata(dev);
4814
4815         return sprintf(buf, "%lld",
4816                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4817 }
4818 static DEVICE_ATTR_RO(resid_cnt);
4819
4820 static struct attribute *st_dev_attrs[] = {
4821         &dev_attr_defined.attr,
4822         &dev_attr_default_blksize.attr,
4823         &dev_attr_default_density.attr,
4824         &dev_attr_default_compression.attr,
4825         &dev_attr_options.attr,
4826         NULL,
4827 };
4828
4829 static struct attribute *st_stats_attrs[] = {
4830         &dev_attr_read_cnt.attr,
4831         &dev_attr_read_byte_cnt.attr,
4832         &dev_attr_read_ns.attr,
4833         &dev_attr_write_cnt.attr,
4834         &dev_attr_write_byte_cnt.attr,
4835         &dev_attr_write_ns.attr,
4836         &dev_attr_in_flight.attr,
4837         &dev_attr_io_ns.attr,
4838         &dev_attr_other_cnt.attr,
4839         &dev_attr_resid_cnt.attr,
4840         NULL,
4841 };
4842
4843 static struct attribute_group stats_group = {
4844         .name = "stats",
4845         .attrs = st_stats_attrs,
4846 };
4847
4848 static struct attribute_group st_group = {
4849         .attrs = st_dev_attrs,
4850 };
4851
4852 static const struct attribute_group *st_dev_groups[] = {
4853         &st_group,
4854         &stats_group,
4855         NULL,
4856 };
4857
4858 /* The following functions may be useful for a larger audience. */
4859 static int sgl_map_user_pages(struct st_buffer *STbp,
4860                               const unsigned int max_pages, unsigned long uaddr,
4861                               size_t count, int rw)
4862 {
4863         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4864         unsigned long start = uaddr >> PAGE_SHIFT;
4865         const int nr_pages = end - start;
4866         int res, i;
4867         struct page **pages;
4868         struct rq_map_data *mdata = &STbp->map_data;
4869
4870         /* User attempted Overflow! */
4871         if ((uaddr + count) < uaddr)
4872                 return -EINVAL;
4873
4874         /* Too big */
4875         if (nr_pages > max_pages)
4876                 return -ENOMEM;
4877
4878         /* Hmm? */
4879         if (count == 0)
4880                 return 0;
4881
4882         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4883         if (pages == NULL)
4884                 return -ENOMEM;
4885
4886         /* Try to fault in all of the necessary pages */
4887         /* rw==READ means read from drive, write into memory area */
4888         res = pin_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4889                                   pages);
4890
4891         /* Errors and no page mapped should return here */
4892         if (res < nr_pages)
4893                 goto out_unmap;
4894
4895         for (i=0; i < nr_pages; i++) {
4896                 /* FIXME: flush superflous for rw==READ,
4897                  * probably wrong function for rw==WRITE
4898                  */
4899                 flush_dcache_page(pages[i]);
4900         }
4901
4902         mdata->offset = uaddr & ~PAGE_MASK;
4903         STbp->mapped_pages = pages;
4904
4905         return nr_pages;
4906  out_unmap:
4907         if (res > 0) {
4908                 unpin_user_pages(pages, res);
4909                 res = 0;
4910         }
4911         kfree(pages);
4912         return res;
4913 }
4914
4915
4916 /* And unmap them... */
4917 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4918                                 const unsigned int nr_pages, int dirtied)
4919 {
4920         /* FIXME: cache flush missing for rw==READ */
4921         unpin_user_pages_dirty_lock(STbp->mapped_pages, nr_pages, dirtied);
4922
4923         kfree(STbp->mapped_pages);
4924         STbp->mapped_pages = NULL;
4925
4926         return 0;
4927 }