drivers/scsi/st.c

   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2010 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20101219";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/slab.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/cdrom.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/delay.h>
  42 #include <linux/mutex.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <asm/dma.h>
  46
  47 #include <scsi/scsi.h>
  48 #include <scsi/scsi_dbg.h>
  49 #include <scsi/scsi_device.h>
  50 #include <scsi/scsi_driver.h>
  51 #include <scsi/scsi_eh.h>
  52 #include <scsi/scsi_host.h>
  53 #include <scsi/scsi_ioctl.h>
  54 #include <scsi/sg.h>
  55
  56
  57 /* The driver prints some debugging information on the console if DEBUG
  58    is defined and non-zero. */
  59 #define DEBUG 1
  60 #define NO_DEBUG 0
  61
  62 #define ST_DEB_MSG  KERN_NOTICE
  63 #if DEBUG
  64 /* The message level for the debug messages is currently set to KERN_NOTICE
  65    so that people can easily see the messages. Later when the debugging messages
  66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67 #define DEB(a) a
  68 #define DEBC(a) if (debugging) { a ; }
  69 #else
  70 #define DEB(a)
  71 #define DEBC(a)
  72 #endif
  73
  74 #define ST_KILOBYTE 1024
  75
  76 #include "st_options.h"
  77 #include "st.h"
  78
  79 static int buffer_kbs;
  80 static int max_sg_segs;
  81 static int try_direct_io = TRY_DIRECT_IO;
  82 static int try_rdio = 1;
  83 static int try_wdio = 1;
  84 static int debug_flag;
  85
  86 static struct class st_sysfs_class;
  87 static const struct attribute_group *st_dev_groups[];
  88 static const struct attribute_group *st_drv_groups[];
  89
  90 MODULE_AUTHOR("Kai Makisara");
  91 MODULE_DESCRIPTION("SCSI tape (st) driver");
  92 MODULE_LICENSE("GPL");
  93 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97  * of sysfs parameters (which module_param doesn't yet support).
  98  * Sysfs parameters defined explicitly later.
  99  */
 100 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104 module_param_named(try_direct_io, try_direct_io, int, 0);
 105 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106 module_param_named(debug_flag, debug_flag, int, 0);
 107 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110 /* Extra parameters for testing */
 111 module_param_named(try_rdio, try_rdio, int, 0);
 112 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113 module_param_named(try_wdio, try_wdio, int, 0);
 114 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116 #ifndef MODULE
 117 static int write_threshold_kbs;  /* retained for compatibility */
 118 static struct st_dev_parm {
 119         char *name;
 120         int *val;
 121 } parms[] __initdata = {
 122         {
 123                 "buffer_kbs", &buffer_kbs
 124         },
 125         {       /* Retained for compatibility with 2.4 */
 126                 "write_threshold_kbs", &write_threshold_kbs
 127         },
 128         {
 129                 "max_sg_segs", NULL
 130         },
 131         {
 132                 "try_direct_io", &try_direct_io
 133         },
 134         {
 135                 "debug_flag", &debug_flag
 136         }
 137 };
 138 #endif
 139
 140 /* Restrict the number of modes so that names for all are assigned */
 141 #if ST_NBR_MODES > 16
 142 #error "Maximum number of modes is 16"
 143 #endif
 144 /* Bit reversed order to get same names for same minors with all
 145    mode counts */
 146 static const char *st_formats[] = {
 147         "",  "r", "k", "s", "l", "t", "o", "u",
 148         "m", "v", "p", "x", "a", "y", "q", "z"};
 149
 150 /* The default definitions have been moved to st_options.h */
 151
 152 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154 /* The buffer size should fit into the 24 bits for length in the
 155    6-byte SCSI read and write commands. */
 156 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158 #endif
 159
 160 static int debugging = DEBUG;
 161
 162 #define MAX_RETRIES 0
 163 #define MAX_WRITE_RETRIES 0
 164 #define MAX_READY_RETRIES 0
 165 #define NO_TAPE  NOT_READY
 166
 167 #define ST_TIMEOUT (900 * HZ)
 168 #define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170 /* Remove mode bits and auto-rewind bit (7) */
 171 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180    24 bits) */
 181 #define SET_DENS_AND_BLK 0x10001
 182
 183 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184 static int st_max_sg_segs = ST_MAX_SG;
 185
 186 static int modes_defined;
 187
 188 static int enlarge_buffer(struct st_buffer *, int, int);
 189 static void clear_buffer(struct st_buffer *);
 190 static void normalize_buffer(struct st_buffer *);
 191 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192 static int from_buffer(struct st_buffer *, char __user *, int);
 193 static void move_buffer_data(struct st_buffer *, int);
 194
 195 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196                               unsigned long, size_t, int);
 197 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199 static int st_probe(struct device *);
 200 static int st_remove(struct device *);
 201
 202 static struct scsi_driver st_template = {
 203         .gendrv = {
 204                 .name           = "st",
 205                 .owner          = THIS_MODULE,
 206                 .probe          = st_probe,
 207                 .remove         = st_remove,
 208                 .groups         = st_drv_groups,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224 static DEFINE_SPINLOCK(st_index_lock);
 225 static DEFINE_SPINLOCK(st_use_lock);
 226 static DEFINE_IDR(st_index_idr);
 227
 228
 229 \f
 230 #include "osst_detect.h"
 231 #ifndef SIGS_FROM_OSST
 232 #define SIGS_FROM_OSST \
 233         {"OnStream", "SC-", "", "osst"}, \
 234         {"OnStream", "DI-", "", "osst"}, \
 235         {"OnStream", "DP-", "", "osst"}, \
 236         {"OnStream", "USB", "", "osst"}, \
 237         {"OnStream", "FW-", "", "osst"}
 238 #endif
 239
 240 static struct scsi_tape *scsi_tape_get(int dev)
 241 {
 242         struct scsi_tape *STp = NULL;
 243
 244         mutex_lock(&st_ref_mutex);
 245         spin_lock(&st_index_lock);
 246
 247         STp = idr_find(&st_index_idr, dev);
 248         if (!STp) goto out;
 249
 250         kref_get(&STp->kref);
 251
 252         if (!STp->device)
 253                 goto out_put;
 254
 255         if (scsi_device_get(STp->device))
 256                 goto out_put;
 257
 258         goto out;
 259
 260 out_put:
 261         kref_put(&STp->kref, scsi_tape_release);
 262         STp = NULL;
 263 out:
 264         spin_unlock(&st_index_lock);
 265         mutex_unlock(&st_ref_mutex);
 266         return STp;
 267 }
 268
 269 static void scsi_tape_put(struct scsi_tape *STp)
 270 {
 271         struct scsi_device *sdev = STp->device;
 272
 273         mutex_lock(&st_ref_mutex);
 274         kref_put(&STp->kref, scsi_tape_release);
 275         scsi_device_put(sdev);
 276         mutex_unlock(&st_ref_mutex);
 277 }
 278
 279 struct st_reject_data {
 280         char *vendor;
 281         char *model;
 282         char *rev;
 283         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284 };
 285
 286 static struct st_reject_data reject_list[] = {
 287         /* {"XXX", "Yy-", "", NULL},  example */
 288         SIGS_FROM_OSST,
 289         {NULL, }};
 290
 291 /* If the device signature is on the list of incompatible drives, the
 292    function returns a pointer to the name of the correct driver (if known) */
 293 static char * st_incompatible(struct scsi_device* SDp)
 294 {
 295         struct st_reject_data *rp;
 296
 297         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301                         if (rp->driver_hint)
 302                                 return rp->driver_hint;
 303                         else
 304                                 return "unknown";
 305                 }
 306         return NULL;
 307 }
 308 \f
 309
 310 static inline char *tape_name(struct scsi_tape *tape)
 311 {
 312         return tape->disk->disk_name;
 313 }
 314
 315 #define st_printk(prefix, t, fmt, a...) \
 316         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317 #ifdef DEBUG
 318 #define DEBC_printk(t, fmt, a...) \
 319         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320 #else
 321 #define DEBC_printk(t, fmt, a...)
 322 #endif
 323
 324 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325 {
 326         const u8 *ucp;
 327         const u8 *sense = SRpnt->sense;
 328
 329         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331         s->flags = 0;
 332
 333         if (s->have_sense) {
 334                 s->deferred = 0;
 335                 s->remainder_valid =
 336                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337                 switch (sense[0] & 0x7f) {
 338                 case 0x71:
 339                         s->deferred = 1;
 340                 case 0x70:
 341                         s->fixed_format = 1;
 342                         s->flags = sense[2] & 0xe0;
 343                         break;
 344                 case 0x73:
 345                         s->deferred = 1;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = tape_name(STp);
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390                                result, driver_byte(result), host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         ktime_t now;
 476
 477         now = ktime_get();
 478         if (req->cmd[0] == WRITE_6) {
 479                 now = ktime_sub(now, STp->stats->write_time);
 480                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482                 atomic64_inc(&STp->stats->write_cnt);
 483                 if (req->errors) {
 484                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 485                                 - STp->buffer->cmdstat.residual,
 486                                 &STp->stats->write_byte_cnt);
 487                         if (STp->buffer->cmdstat.residual > 0)
 488                                 atomic64_inc(&STp->stats->resid_cnt);
 489                 } else
 490                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 491                                 &STp->stats->write_byte_cnt);
 492         } else if (req->cmd[0] == READ_6) {
 493                 now = ktime_sub(now, STp->stats->read_time);
 494                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496                 atomic64_inc(&STp->stats->read_cnt);
 497                 if (req->errors) {
 498                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 499                                 - STp->buffer->cmdstat.residual,
 500                                 &STp->stats->read_byte_cnt);
 501                         if (STp->buffer->cmdstat.residual > 0)
 502                                 atomic64_inc(&STp->stats->resid_cnt);
 503                 } else
 504                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 505                                 &STp->stats->read_byte_cnt);
 506         } else {
 507                 now = ktime_sub(now, STp->stats->other_time);
 508                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509                 atomic64_inc(&STp->stats->other_cnt);
 510         }
 511         atomic64_dec(&STp->stats->in_flight);
 512 }
 513
 514 static void st_scsi_execute_end(struct request *req, int uptodate)
 515 {
 516         struct st_request *SRpnt = req->end_io_data;
 517         struct scsi_tape *STp = SRpnt->stp;
 518         struct bio *tmp;
 519
 520         STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
 521         STp->buffer->cmdstat.residual = req->resid_len;
 522
 523         st_do_stats(STp, req);
 524
 525         tmp = SRpnt->bio;
 526         if (SRpnt->waiting)
 527                 complete(SRpnt->waiting);
 528
 529         blk_rq_unmap_user(tmp);
 530         __blk_put_request(req->q, req);
 531 }
 532
 533 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 534                            int data_direction, void *buffer, unsigned bufflen,
 535                            int timeout, int retries)
 536 {
 537         struct request *req;
 538         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 539         int err = 0;
 540         int write = (data_direction == DMA_TO_DEVICE);
 541         struct scsi_tape *STp = SRpnt->stp;
 542
 543         req = blk_get_request(SRpnt->stp->device->request_queue, write,
 544                               GFP_KERNEL);
 545         if (IS_ERR(req))
 546                 return DRIVER_ERROR << 24;
 547
 548         blk_rq_set_block_pc(req);
 549         req->cmd_flags |= REQ_QUIET;
 550
 551         mdata->null_mapped = 1;
 552
 553         if (bufflen) {
 554                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 555                                       GFP_KERNEL);
 556                 if (err) {
 557                         blk_put_request(req);
 558                         return DRIVER_ERROR << 24;
 559                 }
 560         }
 561
 562         atomic64_inc(&STp->stats->in_flight);
 563         if (cmd[0] == WRITE_6) {
 564                 atomic_set(&STp->stats->last_write_size, bufflen);
 565                 STp->stats->write_time = ktime_get();
 566         } else if (cmd[0] == READ_6) {
 567                 atomic_set(&STp->stats->last_read_size, bufflen);
 568                 STp->stats->read_time = ktime_get();
 569         } else {
 570                 STp->stats->other_time = ktime_get();
 571         }
 572
 573         SRpnt->bio = req->bio;
 574         req->cmd_len = COMMAND_SIZE(cmd[0]);
 575         memset(req->cmd, 0, BLK_MAX_CDB);
 576         memcpy(req->cmd, cmd, req->cmd_len);
 577         req->sense = SRpnt->sense;
 578         req->sense_len = 0;
 579         req->timeout = timeout;
 580         req->retries = retries;
 581         req->end_io_data = SRpnt;
 582
 583         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 584         return 0;
 585 }
 586
 587 /* Do the scsi command. Waits until command performed if do_wait is true.
 588    Otherwise write_behind_check() is used to check that the command
 589    has finished. */
 590 static struct st_request *
 591 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 592            int bytes, int direction, int timeout, int retries, int do_wait)
 593 {
 594         struct completion *waiting;
 595         struct rq_map_data *mdata = &STp->buffer->map_data;
 596         int ret;
 597
 598         /* if async, make sure there's no command outstanding */
 599         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 600                 st_printk(KERN_ERR, STp,
 601                           "Async command already active.\n");
 602                 if (signal_pending(current))
 603                         (STp->buffer)->syscall_result = (-EINTR);
 604                 else
 605                         (STp->buffer)->syscall_result = (-EBUSY);
 606                 return NULL;
 607         }
 608
 609         if (!SRpnt) {
 610                 SRpnt = st_allocate_request(STp);
 611                 if (!SRpnt)
 612                         return NULL;
 613         }
 614
 615         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 616            which IO is outstanding. It's nulled out when the IO completes. */
 617         if (!do_wait)
 618                 (STp->buffer)->last_SRpnt = SRpnt;
 619
 620         waiting = &STp->wait;
 621         init_completion(waiting);
 622         SRpnt->waiting = waiting;
 623
 624         if (STp->buffer->do_dio) {
 625                 mdata->page_order = 0;
 626                 mdata->nr_entries = STp->buffer->sg_segs;
 627                 mdata->pages = STp->buffer->mapped_pages;
 628         } else {
 629                 mdata->page_order = STp->buffer->reserved_page_order;
 630                 mdata->nr_entries =
 631                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 632                 mdata->pages = STp->buffer->reserved_pages;
 633                 mdata->offset = 0;
 634         }
 635
 636         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 637         STp->buffer->cmdstat.have_sense = 0;
 638         STp->buffer->syscall_result = 0;
 639
 640         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 641                               retries);
 642         if (ret) {
 643                 /* could not allocate the buffer or request was too large */
 644                 (STp->buffer)->syscall_result = (-EBUSY);
 645                 (STp->buffer)->last_SRpnt = NULL;
 646         } else if (do_wait) {
 647                 wait_for_completion(waiting);
 648                 SRpnt->waiting = NULL;
 649                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 650         }
 651
 652         return SRpnt;
 653 }
 654
 655
 656 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 657    write has been correct but EOM early warning reached, -EIO if write ended in
 658    error or zero if write successful. Asynchronous writes are used only in
 659    variable block mode. */
 660 static int write_behind_check(struct scsi_tape * STp)
 661 {
 662         int retval = 0;
 663         struct st_buffer *STbuffer;
 664         struct st_partstat *STps;
 665         struct st_cmdstatus *cmdstatp;
 666         struct st_request *SRpnt;
 667
 668         STbuffer = STp->buffer;
 669         if (!STbuffer->writing)
 670                 return 0;
 671
 672         DEB(
 673         if (STp->write_pending)
 674                 STp->nbr_waits++;
 675         else
 676                 STp->nbr_finished++;
 677         ) /* end DEB */
 678
 679         wait_for_completion(&(STp->wait));
 680         SRpnt = STbuffer->last_SRpnt;
 681         STbuffer->last_SRpnt = NULL;
 682         SRpnt->waiting = NULL;
 683
 684         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 685         st_release_request(SRpnt);
 686
 687         STbuffer->buffer_bytes -= STbuffer->writing;
 688         STps = &(STp->ps[STp->partition]);
 689         if (STps->drv_block >= 0) {
 690                 if (STp->block_size == 0)
 691                         STps->drv_block++;
 692                 else
 693                         STps->drv_block += STbuffer->writing / STp->block_size;
 694         }
 695
 696         cmdstatp = &STbuffer->cmdstat;
 697         if (STbuffer->syscall_result) {
 698                 retval = -EIO;
 699                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 700                     (cmdstatp->flags & SENSE_EOM) &&
 701                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 702                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 703                         /* EOM at write-behind, has all data been written? */
 704                         if (!cmdstatp->remainder_valid ||
 705                             cmdstatp->uremainder64 == 0)
 706                                 retval = -ENOSPC;
 707                 }
 708                 if (retval == -EIO)
 709                         STps->drv_block = -1;
 710         }
 711         STbuffer->writing = 0;
 712
 713         DEB(if (debugging && retval)
 714                     st_printk(ST_DEB_MSG, STp,
 715                                 "Async write error %x, return value %d.\n",
 716                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 717
 718         return retval;
 719 }
 720
 721
 722 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 723    it messes up the block number). */
 724 static int cross_eof(struct scsi_tape * STp, int forward)
 725 {
 726         struct st_request *SRpnt;
 727         unsigned char cmd[MAX_COMMAND_SIZE];
 728
 729         cmd[0] = SPACE;
 730         cmd[1] = 0x01;          /* Space FileMarks */
 731         if (forward) {
 732                 cmd[2] = cmd[3] = 0;
 733                 cmd[4] = 1;
 734         } else
 735                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 736         cmd[5] = 0;
 737
 738         DEBC_printk(STp, "Stepping over filemark %s.\n",
 739                     forward ? "forward" : "backward");
 740
 741         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 742                            STp->device->request_queue->rq_timeout,
 743                            MAX_RETRIES, 1);
 744         if (!SRpnt)
 745                 return (STp->buffer)->syscall_result;
 746
 747         st_release_request(SRpnt);
 748         SRpnt = NULL;
 749
 750         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 751                 st_printk(KERN_ERR, STp,
 752                           "Stepping over filemark %s failed.\n",
 753                           forward ? "forward" : "backward");
 754
 755         return (STp->buffer)->syscall_result;
 756 }
 757
 758
 759 /* Flush the write buffer (never need to write if variable blocksize). */
 760 static int st_flush_write_buffer(struct scsi_tape * STp)
 761 {
 762         int transfer, blks;
 763         int result;
 764         unsigned char cmd[MAX_COMMAND_SIZE];
 765         struct st_request *SRpnt;
 766         struct st_partstat *STps;
 767
 768         result = write_behind_check(STp);
 769         if (result)
 770                 return result;
 771
 772         result = 0;
 773         if (STp->dirty == 1) {
 774
 775                 transfer = STp->buffer->buffer_bytes;
 776                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 777
 778                 memset(cmd, 0, MAX_COMMAND_SIZE);
 779                 cmd[0] = WRITE_6;
 780                 cmd[1] = 1;
 781                 blks = transfer / STp->block_size;
 782                 cmd[2] = blks >> 16;
 783                 cmd[3] = blks >> 8;
 784                 cmd[4] = blks;
 785
 786                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 787                                    STp->device->request_queue->rq_timeout,
 788                                    MAX_WRITE_RETRIES, 1);
 789                 if (!SRpnt)
 790                         return (STp->buffer)->syscall_result;
 791
 792                 STps = &(STp->ps[STp->partition]);
 793                 if ((STp->buffer)->syscall_result != 0) {
 794                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 795
 796                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 797                             (cmdstatp->flags & SENSE_EOM) &&
 798                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 799                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 800                             (!cmdstatp->remainder_valid ||
 801                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 802                                 STp->dirty = 0;
 803                                 (STp->buffer)->buffer_bytes = 0;
 804                                 if (STps->drv_block >= 0)
 805                                         STps->drv_block += blks;
 806                                 result = (-ENOSPC);
 807                         } else {
 808                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 809                                 STps->drv_block = (-1);
 810                                 result = (-EIO);
 811                         }
 812                 } else {
 813                         if (STps->drv_block >= 0)
 814                                 STps->drv_block += blks;
 815                         STp->dirty = 0;
 816                         (STp->buffer)->buffer_bytes = 0;
 817                 }
 818                 st_release_request(SRpnt);
 819                 SRpnt = NULL;
 820         }
 821         return result;
 822 }
 823
 824
 825 /* Flush the tape buffer. The tape will be positioned correctly unless
 826    seek_next is true. */
 827 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 828 {
 829         int backspace, result;
 830         struct st_buffer *STbuffer;
 831         struct st_partstat *STps;
 832
 833         STbuffer = STp->buffer;
 834
 835         /*
 836          * If there was a bus reset, block further access
 837          * to this device.
 838          */
 839         if (STp->pos_unknown)
 840                 return (-EIO);
 841
 842         if (STp->ready != ST_READY)
 843                 return 0;
 844         STps = &(STp->ps[STp->partition]);
 845         if (STps->rw == ST_WRITING)     /* Writing */
 846                 return st_flush_write_buffer(STp);
 847
 848         if (STp->block_size == 0)
 849                 return 0;
 850
 851         backspace = ((STp->buffer)->buffer_bytes +
 852                      (STp->buffer)->read_pointer) / STp->block_size -
 853             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 854             STp->block_size;
 855         (STp->buffer)->buffer_bytes = 0;
 856         (STp->buffer)->read_pointer = 0;
 857         result = 0;
 858         if (!seek_next) {
 859                 if (STps->eof == ST_FM_HIT) {
 860                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 861                         if (!result)
 862                                 STps->eof = ST_NOEOF;
 863                         else {
 864                                 if (STps->drv_file >= 0)
 865                                         STps->drv_file++;
 866                                 STps->drv_block = 0;
 867                         }
 868                 }
 869                 if (!result && backspace > 0)
 870                         result = st_int_ioctl(STp, MTBSR, backspace);
 871         } else if (STps->eof == ST_FM_HIT) {
 872                 if (STps->drv_file >= 0)
 873                         STps->drv_file++;
 874                 STps->drv_block = 0;
 875                 STps->eof = ST_NOEOF;
 876         }
 877         return result;
 878
 879 }
 880 \f
 881 /* Set the mode parameters */
 882 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 883 {
 884         int set_it = 0;
 885         unsigned long arg;
 886
 887         if (!STp->density_changed &&
 888             STm->default_density >= 0 &&
 889             STm->default_density != STp->density) {
 890                 arg = STm->default_density;
 891                 set_it = 1;
 892         } else
 893                 arg = STp->density;
 894         arg <<= MT_ST_DENSITY_SHIFT;
 895         if (!STp->blksize_changed &&
 896             STm->default_blksize >= 0 &&
 897             STm->default_blksize != STp->block_size) {
 898                 arg |= STm->default_blksize;
 899                 set_it = 1;
 900         } else
 901                 arg |= STp->block_size;
 902         if (set_it &&
 903             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 904                 st_printk(KERN_WARNING, STp,
 905                           "Can't set default block size to %d bytes "
 906                           "and density %x.\n",
 907                           STm->default_blksize, STm->default_density);
 908                 if (modes_defined)
 909                         return (-EINVAL);
 910         }
 911         return 0;
 912 }
 913
 914
 915 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 916 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 917 {
 918         int retval;
 919
 920         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 921
 922         retval = scsi_set_medium_removal(STp->device,
 923                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 924         if (!retval)
 925                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 926         else
 927                 STp->door_locked = ST_LOCK_FAILS;
 928         return retval;
 929 }
 930
 931
 932 /* Set the internal state after reset */
 933 static void reset_state(struct scsi_tape *STp)
 934 {
 935         int i;
 936         struct st_partstat *STps;
 937
 938         STp->pos_unknown = 0;
 939         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 940                 STps = &(STp->ps[i]);
 941                 STps->rw = ST_IDLE;
 942                 STps->eof = ST_NOEOF;
 943                 STps->at_sm = 0;
 944                 STps->last_block_valid = 0;
 945                 STps->drv_block = -1;
 946                 STps->drv_file = -1;
 947         }
 948         if (STp->can_partitions) {
 949                 STp->partition = find_partition(STp);
 950                 if (STp->partition < 0)
 951                         STp->partition = 0;
 952                 STp->new_partition = STp->partition;
 953         }
 954 }
 955 \f
 956 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 957    error code. */
 958 #define CHKRES_READY       0
 959 #define CHKRES_NEW_SESSION 1
 960 #define CHKRES_NOT_READY   2
 961 #define CHKRES_NO_TAPE     3
 962
 963 #define MAX_ATTENTIONS    10
 964
 965 static int test_ready(struct scsi_tape *STp, int do_wait)
 966 {
 967         int attentions, waits, max_wait, scode;
 968         int retval = CHKRES_READY, new_session = 0;
 969         unsigned char cmd[MAX_COMMAND_SIZE];
 970         struct st_request *SRpnt = NULL;
 971         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 972
 973         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 974
 975         for (attentions=waits=0; ; ) {
 976                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 977                 cmd[0] = TEST_UNIT_READY;
 978                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 979                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 980
 981                 if (!SRpnt) {
 982                         retval = (STp->buffer)->syscall_result;
 983                         break;
 984                 }
 985
 986                 if (cmdstatp->have_sense) {
 987
 988                         scode = cmdstatp->sense_hdr.sense_key;
 989
 990                         if (scode == UNIT_ATTENTION) { /* New media? */
 991                                 new_session = 1;
 992                                 if (attentions < MAX_ATTENTIONS) {
 993                                         attentions++;
 994                                         continue;
 995                                 }
 996                                 else {
 997                                         retval = (-EIO);
 998                                         break;
 999                                 }
1000                         }
1001
1002                         if (scode == NOT_READY) {
1003                                 if (waits < max_wait) {
1004                                         if (msleep_interruptible(1000)) {
1005                                                 retval = (-EINTR);
1006                                                 break;
1007                                         }
1008                                         waits++;
1009                                         continue;
1010                                 }
1011                                 else {
1012                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1013                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1014                                                 retval = CHKRES_NO_TAPE;
1015                                         else
1016                                                 retval = CHKRES_NOT_READY;
1017                                         break;
1018                                 }
1019                         }
1020                 }
1021
1022                 retval = (STp->buffer)->syscall_result;
1023                 if (!retval)
1024                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1025                 break;
1026         }
1027
1028         if (SRpnt != NULL)
1029                 st_release_request(SRpnt);
1030         return retval;
1031 }
1032
1033
1034 /* See if the drive is ready and gather information about the tape. Return values:
1035    < 0   negative error code from errno.h
1036    0     drive ready
1037    1     drive not ready (possibly no tape)
1038 */
1039 static int check_tape(struct scsi_tape *STp, struct file *filp)
1040 {
1041         int i, retval, new_session = 0, do_wait;
1042         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1043         unsigned short st_flags = filp->f_flags;
1044         struct st_request *SRpnt = NULL;
1045         struct st_modedef *STm;
1046         struct st_partstat *STps;
1047         struct inode *inode = file_inode(filp);
1048         int mode = TAPE_MODE(inode);
1049
1050         STp->ready = ST_READY;
1051
1052         if (mode != STp->current_mode) {
1053                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1054                             STp->current_mode, mode);
1055                 new_session = 1;
1056                 STp->current_mode = mode;
1057         }
1058         STm = &(STp->modes[STp->current_mode]);
1059
1060         saved_cleaning = STp->cleaning_req;
1061         STp->cleaning_req = 0;
1062
1063         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1064         retval = test_ready(STp, do_wait);
1065
1066         if (retval < 0)
1067             goto err_out;
1068
1069         if (retval == CHKRES_NEW_SESSION) {
1070                 STp->pos_unknown = 0;
1071                 STp->partition = STp->new_partition = 0;
1072                 if (STp->can_partitions)
1073                         STp->nbr_partitions = 1; /* This guess will be updated later
1074                                                     if necessary */
1075                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1076                         STps = &(STp->ps[i]);
1077                         STps->rw = ST_IDLE;
1078                         STps->eof = ST_NOEOF;
1079                         STps->at_sm = 0;
1080                         STps->last_block_valid = 0;
1081                         STps->drv_block = 0;
1082                         STps->drv_file = 0;
1083                 }
1084                 new_session = 1;
1085         }
1086         else {
1087                 STp->cleaning_req |= saved_cleaning;
1088
1089                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1090                         if (retval == CHKRES_NO_TAPE)
1091                                 STp->ready = ST_NO_TAPE;
1092                         else
1093                                 STp->ready = ST_NOT_READY;
1094
1095                         STp->density = 0;       /* Clear the erroneous "residue" */
1096                         STp->write_prot = 0;
1097                         STp->block_size = 0;
1098                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1099                         STp->partition = STp->new_partition = 0;
1100                         STp->door_locked = ST_UNLOCKED;
1101                         return CHKRES_NOT_READY;
1102                 }
1103         }
1104
1105         if (STp->omit_blklims)
1106                 STp->min_block = STp->max_block = (-1);
1107         else {
1108                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1109                 cmd[0] = READ_BLOCK_LIMITS;
1110
1111                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1112                                    STp->device->request_queue->rq_timeout,
1113                                    MAX_READY_RETRIES, 1);
1114                 if (!SRpnt) {
1115                         retval = (STp->buffer)->syscall_result;
1116                         goto err_out;
1117                 }
1118
1119                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1120                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1121                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1122                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1123                             (STp->buffer)->b_data[5];
1124                         if ( DEB( debugging || ) !STp->inited)
1125                                 st_printk(KERN_INFO, STp,
1126                                           "Block limits %d - %d bytes.\n",
1127                                           STp->min_block, STp->max_block);
1128                 } else {
1129                         STp->min_block = STp->max_block = (-1);
1130                         DEBC_printk(STp, "Can't read block limits.\n");
1131                 }
1132         }
1133
1134         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1135         cmd[0] = MODE_SENSE;
1136         cmd[4] = 12;
1137
1138         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1139                            STp->device->request_queue->rq_timeout,
1140                            MAX_READY_RETRIES, 1);
1141         if (!SRpnt) {
1142                 retval = (STp->buffer)->syscall_result;
1143                 goto err_out;
1144         }
1145
1146         if ((STp->buffer)->syscall_result != 0) {
1147                 DEBC_printk(STp, "No Mode Sense.\n");
1148                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1149                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1150                 STp->drv_write_prot = 0;
1151         } else {
1152                 DEBC_printk(STp,"Mode sense. Length %d, "
1153                             "medium %x, WBS %x, BLL %d\n",
1154                             (STp->buffer)->b_data[0],
1155                             (STp->buffer)->b_data[1],
1156                             (STp->buffer)->b_data[2],
1157                             (STp->buffer)->b_data[3]);
1158
1159                 if ((STp->buffer)->b_data[3] >= 8) {
1160                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1161                         STp->density = (STp->buffer)->b_data[4];
1162                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1163                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1164                         DEBC_printk(STp, "Density %x, tape length: %x, "
1165                                     "drv buffer: %d\n",
1166                                     STp->density,
1167                                     (STp->buffer)->b_data[5] * 65536 +
1168                                     (STp->buffer)->b_data[6] * 256 +
1169                                     (STp->buffer)->b_data[7],
1170                                     STp->drv_buffer);
1171                 }
1172                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1173                 if (!STp->drv_buffer && STp->immediate_filemark) {
1174                         st_printk(KERN_WARNING, STp,
1175                                   "non-buffered tape: disabling "
1176                                   "writing immediate filemarks\n");
1177                         STp->immediate_filemark = 0;
1178                 }
1179         }
1180         st_release_request(SRpnt);
1181         SRpnt = NULL;
1182         STp->inited = 1;
1183
1184         if (STp->block_size > 0)
1185                 (STp->buffer)->buffer_blocks =
1186                         (STp->buffer)->buffer_size / STp->block_size;
1187         else
1188                 (STp->buffer)->buffer_blocks = 1;
1189         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1190
1191         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1192                     STp->block_size, (STp->buffer)->buffer_size,
1193                     (STp->buffer)->buffer_blocks);
1194
1195         if (STp->drv_write_prot) {
1196                 STp->write_prot = 1;
1197
1198                 DEBC_printk(STp, "Write protected\n");
1199
1200                 if (do_wait &&
1201                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1202                      (st_flags & O_ACCMODE) == O_RDWR)) {
1203                         retval = (-EROFS);
1204                         goto err_out;
1205                 }
1206         }
1207
1208         if (STp->can_partitions && STp->nbr_partitions < 1) {
1209                 /* This code is reached when the device is opened for the first time
1210                    after the driver has been initialized with tape in the drive and the
1211                    partition support has been enabled. */
1212                 DEBC_printk(STp, "Updating partition number in status.\n");
1213                 if ((STp->partition = find_partition(STp)) < 0) {
1214                         retval = STp->partition;
1215                         goto err_out;
1216                 }
1217                 STp->new_partition = STp->partition;
1218                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1219         }
1220
1221         if (new_session) {      /* Change the drive parameters for the new mode */
1222                 STp->density_changed = STp->blksize_changed = 0;
1223                 STp->compression_changed = 0;
1224                 if (!(STm->defaults_for_writes) &&
1225                     (retval = set_mode_densblk(STp, STm)) < 0)
1226                     goto err_out;
1227
1228                 if (STp->default_drvbuffer != 0xff) {
1229                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1230                                 st_printk(KERN_WARNING, STp,
1231                                           "Can't set default drive "
1232                                           "buffering to %d.\n",
1233                                           STp->default_drvbuffer);
1234                 }
1235         }
1236
1237         return CHKRES_READY;
1238
1239  err_out:
1240         return retval;
1241 }
1242
1243
1244 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1245    module count. */
1246 static int st_open(struct inode *inode, struct file *filp)
1247 {
1248         int i, retval = (-EIO);
1249         int resumed = 0;
1250         struct scsi_tape *STp;
1251         struct st_partstat *STps;
1252         int dev = TAPE_NR(inode);
1253
1254         /*
1255          * We really want to do nonseekable_open(inode, filp); here, but some
1256          * versions of tar incorrectly call lseek on tapes and bail out if that
1257          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1258          */
1259         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1260
1261         if (!(STp = scsi_tape_get(dev))) {
1262                 return -ENXIO;
1263         }
1264
1265         filp->private_data = STp;
1266
1267         spin_lock(&st_use_lock);
1268         if (STp->in_use) {
1269                 spin_unlock(&st_use_lock);
1270                 scsi_tape_put(STp);
1271                 DEBC_printk(STp, "Device already in use.\n");
1272                 return (-EBUSY);
1273         }
1274
1275         STp->in_use = 1;
1276         spin_unlock(&st_use_lock);
1277         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1278
1279         if (scsi_autopm_get_device(STp->device) < 0) {
1280                 retval = -EIO;
1281                 goto err_out;
1282         }
1283         resumed = 1;
1284         if (!scsi_block_when_processing_errors(STp->device)) {
1285                 retval = (-ENXIO);
1286                 goto err_out;
1287         }
1288
1289         /* See that we have at least a one page buffer available */
1290         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1291                 st_printk(KERN_WARNING, STp,
1292                           "Can't allocate one page tape buffer.\n");
1293                 retval = (-EOVERFLOW);
1294                 goto err_out;
1295         }
1296
1297         (STp->buffer)->cleared = 0;
1298         (STp->buffer)->writing = 0;
1299         (STp->buffer)->syscall_result = 0;
1300
1301         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1302
1303         STp->dirty = 0;
1304         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1305                 STps = &(STp->ps[i]);
1306                 STps->rw = ST_IDLE;
1307         }
1308         STp->try_dio_now = STp->try_dio;
1309         STp->recover_count = 0;
1310         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1311              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1312
1313         retval = check_tape(STp, filp);
1314         if (retval < 0)
1315                 goto err_out;
1316         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1317             retval != CHKRES_READY) {
1318                 if (STp->ready == NO_TAPE)
1319                         retval = (-ENOMEDIUM);
1320                 else
1321                         retval = (-EIO);
1322                 goto err_out;
1323         }
1324         return 0;
1325
1326  err_out:
1327         normalize_buffer(STp->buffer);
1328         spin_lock(&st_use_lock);
1329         STp->in_use = 0;
1330         spin_unlock(&st_use_lock);
1331         if (resumed)
1332                 scsi_autopm_put_device(STp->device);
1333         scsi_tape_put(STp);
1334         return retval;
1335
1336 }
1337 \f
1338
1339 /* Flush the tape buffer before close */
1340 static int st_flush(struct file *filp, fl_owner_t id)
1341 {
1342         int result = 0, result2;
1343         unsigned char cmd[MAX_COMMAND_SIZE];
1344         struct st_request *SRpnt;
1345         struct scsi_tape *STp = filp->private_data;
1346         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1347         struct st_partstat *STps = &(STp->ps[STp->partition]);
1348
1349         if (file_count(filp) > 1)
1350                 return 0;
1351
1352         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1353                 result = st_flush_write_buffer(STp);
1354                 if (result != 0 && result != (-ENOSPC))
1355                         goto out;
1356         }
1357
1358         if (STp->can_partitions &&
1359             (result2 = switch_partition(STp)) < 0) {
1360                 DEBC_printk(STp, "switch_partition at close failed.\n");
1361                 if (result == 0)
1362                         result = result2;
1363                 goto out;
1364         }
1365
1366         DEBC( if (STp->nbr_requests)
1367                 st_printk(KERN_DEBUG, STp,
1368                           "Number of r/w requests %d, dio used in %d, "
1369                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1370                           STp->nbr_pages));
1371
1372         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1373                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1374
1375 #if DEBUG
1376                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1377                             STp->nbr_waits, STp->nbr_finished);
1378 #endif
1379                 memset(cmd, 0, MAX_COMMAND_SIZE);
1380                 cmd[0] = WRITE_FILEMARKS;
1381                 if (STp->immediate_filemark)
1382                         cmd[1] = 1;
1383                 cmd[4] = 1 + STp->two_fm;
1384
1385                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1386                                    STp->device->request_queue->rq_timeout,
1387                                    MAX_WRITE_RETRIES, 1);
1388                 if (!SRpnt) {
1389                         result = (STp->buffer)->syscall_result;
1390                         goto out;
1391                 }
1392
1393                 if (STp->buffer->syscall_result == 0 ||
1394                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1395                      (cmdstatp->flags & SENSE_EOM) &&
1396                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1397                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1398                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1399                         /* Write successful at EOM */
1400                         st_release_request(SRpnt);
1401                         SRpnt = NULL;
1402                         if (STps->drv_file >= 0)
1403                                 STps->drv_file++;
1404                         STps->drv_block = 0;
1405                         if (STp->two_fm)
1406                                 cross_eof(STp, 0);
1407                         STps->eof = ST_FM;
1408                 }
1409                 else { /* Write error */
1410                         st_release_request(SRpnt);
1411                         SRpnt = NULL;
1412                         st_printk(KERN_ERR, STp,
1413                                   "Error on write filemark.\n");
1414                         if (result == 0)
1415                                 result = (-EIO);
1416                 }
1417
1418                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1419         } else if (!STp->rew_at_close) {
1420                 STps = &(STp->ps[STp->partition]);
1421                 if (!STm->sysv || STps->rw != ST_READING) {
1422                         if (STp->can_bsr)
1423                                 result = flush_buffer(STp, 0);
1424                         else if (STps->eof == ST_FM_HIT) {
1425                                 result = cross_eof(STp, 0);
1426                                 if (result) {
1427                                         if (STps->drv_file >= 0)
1428                                                 STps->drv_file++;
1429                                         STps->drv_block = 0;
1430                                         STps->eof = ST_FM;
1431                                 } else
1432                                         STps->eof = ST_NOEOF;
1433                         }
1434                 } else if ((STps->eof == ST_NOEOF &&
1435                             !(result = cross_eof(STp, 1))) ||
1436                            STps->eof == ST_FM_HIT) {
1437                         if (STps->drv_file >= 0)
1438                                 STps->drv_file++;
1439                         STps->drv_block = 0;
1440                         STps->eof = ST_FM;
1441                 }
1442         }
1443
1444       out:
1445         if (STp->rew_at_close) {
1446                 result2 = st_int_ioctl(STp, MTREW, 1);
1447                 if (result == 0)
1448                         result = result2;
1449         }
1450         return result;
1451 }
1452
1453
1454 /* Close the device and release it. BKL is not needed: this is the only thread
1455    accessing this tape. */
1456 static int st_release(struct inode *inode, struct file *filp)
1457 {
1458         int result = 0;
1459         struct scsi_tape *STp = filp->private_data;
1460
1461         if (STp->door_locked == ST_LOCKED_AUTO)
1462                 do_door_lock(STp, 0);
1463
1464         normalize_buffer(STp->buffer);
1465         spin_lock(&st_use_lock);
1466         STp->in_use = 0;
1467         spin_unlock(&st_use_lock);
1468         scsi_autopm_put_device(STp->device);
1469         scsi_tape_put(STp);
1470
1471         return result;
1472 }
1473 \f
1474 /* The checks common to both reading and writing */
1475 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1476 {
1477         ssize_t retval = 0;
1478
1479         /*
1480          * If we are in the middle of error recovery, don't let anyone
1481          * else try and use this device.  Also, if error recovery fails, it
1482          * may try and take the device offline, in which case all further
1483          * access to the device is prohibited.
1484          */
1485         if (!scsi_block_when_processing_errors(STp->device)) {
1486                 retval = (-ENXIO);
1487                 goto out;
1488         }
1489
1490         if (STp->ready != ST_READY) {
1491                 if (STp->ready == ST_NO_TAPE)
1492                         retval = (-ENOMEDIUM);
1493                 else
1494                         retval = (-EIO);
1495                 goto out;
1496         }
1497
1498         if (! STp->modes[STp->current_mode].defined) {
1499                 retval = (-ENXIO);
1500                 goto out;
1501         }
1502
1503
1504         /*
1505          * If there was a bus reset, block further access
1506          * to this device.
1507          */
1508         if (STp->pos_unknown) {
1509                 retval = (-EIO);
1510                 goto out;
1511         }
1512
1513         if (count == 0)
1514                 goto out;
1515
1516         DEB(
1517         if (!STp->in_use) {
1518                 st_printk(ST_DEB_MSG, STp,
1519                           "Incorrect device.\n");
1520                 retval = (-EIO);
1521                 goto out;
1522         } ) /* end DEB */
1523
1524         if (STp->can_partitions &&
1525             (retval = switch_partition(STp)) < 0)
1526                 goto out;
1527
1528         if (STp->block_size == 0 && STp->max_block > 0 &&
1529             (count < STp->min_block || count > STp->max_block)) {
1530                 retval = (-EINVAL);
1531                 goto out;
1532         }
1533
1534         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1535             !do_door_lock(STp, 1))
1536                 STp->door_locked = ST_LOCKED_AUTO;
1537
1538  out:
1539         return retval;
1540 }
1541
1542
1543 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1544                            size_t count, int is_read)
1545 {
1546         int i, bufsize, retval = 0;
1547         struct st_buffer *STbp = STp->buffer;
1548
1549         if (is_read)
1550                 i = STp->try_dio_now && try_rdio;
1551         else
1552                 i = STp->try_dio_now && try_wdio;
1553
1554         if (i && ((unsigned long)buf & queue_dma_alignment(
1555                                         STp->device->request_queue)) == 0) {
1556                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1557                                        count, (is_read ? READ : WRITE));
1558                 if (i > 0) {
1559                         STbp->do_dio = i;
1560                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1561                 }
1562                 else
1563                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1564                 STbp->sg_segs = STbp->do_dio;
1565                 DEB(
1566                      if (STbp->do_dio) {
1567                         STp->nbr_dio++;
1568                         STp->nbr_pages += STbp->do_dio;
1569                      }
1570                 )
1571         } else
1572                 STbp->do_dio = 0;
1573         DEB( STp->nbr_requests++; )
1574
1575         if (!STbp->do_dio) {
1576                 if (STp->block_size)
1577                         bufsize = STp->block_size > st_fixed_buffer_size ?
1578                                 STp->block_size : st_fixed_buffer_size;
1579                 else {
1580                         bufsize = count;
1581                         /* Make sure that data from previous user is not leaked even if
1582                            HBA does not return correct residual */
1583                         if (is_read && STp->sili && !STbp->cleared)
1584                                 clear_buffer(STbp);
1585                 }
1586
1587                 if (bufsize > STbp->buffer_size &&
1588                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1589                         st_printk(KERN_WARNING, STp,
1590                                   "Can't allocate %d byte tape buffer.\n",
1591                                   bufsize);
1592                         retval = (-EOVERFLOW);
1593                         goto out;
1594                 }
1595                 if (STp->block_size)
1596                         STbp->buffer_blocks = bufsize / STp->block_size;
1597         }
1598
1599  out:
1600         return retval;
1601 }
1602
1603
1604 /* Can be called more than once after each setup_buffer() */
1605 static void release_buffering(struct scsi_tape *STp, int is_read)
1606 {
1607         struct st_buffer *STbp;
1608
1609         STbp = STp->buffer;
1610         if (STbp->do_dio) {
1611                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1612                 STbp->do_dio = 0;
1613                 STbp->sg_segs = 0;
1614         }
1615 }
1616
1617
1618 /* Write command */
1619 static ssize_t
1620 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1621 {
1622         ssize_t total;
1623         ssize_t i, do_count, blks, transfer;
1624         ssize_t retval;
1625         int undone, retry_eot = 0, scode;
1626         int async_write;
1627         unsigned char cmd[MAX_COMMAND_SIZE];
1628         const char __user *b_point;
1629         struct st_request *SRpnt = NULL;
1630         struct scsi_tape *STp = filp->private_data;
1631         struct st_modedef *STm;
1632         struct st_partstat *STps;
1633         struct st_buffer *STbp;
1634
1635         if (mutex_lock_interruptible(&STp->lock))
1636                 return -ERESTARTSYS;
1637
1638         retval = rw_checks(STp, filp, count);
1639         if (retval || count == 0)
1640                 goto out;
1641
1642         /* Write must be integral number of blocks */
1643         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1644                 st_printk(KERN_WARNING, STp,
1645                           "Write not multiple of tape block size.\n");
1646                 retval = (-EINVAL);
1647                 goto out;
1648         }
1649
1650         STm = &(STp->modes[STp->current_mode]);
1651         STps = &(STp->ps[STp->partition]);
1652
1653         if (STp->write_prot) {
1654                 retval = (-EACCES);
1655                 goto out;
1656         }
1657
1658
1659         if (STps->rw == ST_READING) {
1660                 retval = flush_buffer(STp, 0);
1661                 if (retval)
1662                         goto out;
1663                 STps->rw = ST_WRITING;
1664         } else if (STps->rw != ST_WRITING &&
1665                    STps->drv_file == 0 && STps->drv_block == 0) {
1666                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1667                         goto out;
1668                 if (STm->default_compression != ST_DONT_TOUCH &&
1669                     !(STp->compression_changed)) {
1670                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1671                                 st_printk(KERN_WARNING, STp,
1672                                           "Can't set default compression.\n");
1673                                 if (modes_defined) {
1674                                         retval = (-EINVAL);
1675                                         goto out;
1676                                 }
1677                         }
1678                 }
1679         }
1680
1681         STbp = STp->buffer;
1682         i = write_behind_check(STp);
1683         if (i) {
1684                 if (i == -ENOSPC)
1685                         STps->eof = ST_EOM_OK;
1686                 else
1687                         STps->eof = ST_EOM_ERROR;
1688         }
1689
1690         if (STps->eof == ST_EOM_OK) {
1691                 STps->eof = ST_EOD_1;  /* allow next write */
1692                 retval = (-ENOSPC);
1693                 goto out;
1694         }
1695         else if (STps->eof == ST_EOM_ERROR) {
1696                 retval = (-EIO);
1697                 goto out;
1698         }
1699
1700         /* Check the buffer readability in cases where copy_user might catch
1701            the problems after some tape movement. */
1702         if (STp->block_size != 0 &&
1703             !STbp->do_dio &&
1704             (copy_from_user(&i, buf, 1) != 0 ||
1705              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1706                 retval = (-EFAULT);
1707                 goto out;
1708         }
1709
1710         retval = setup_buffering(STp, buf, count, 0);
1711         if (retval)
1712                 goto out;
1713
1714         total = count;
1715
1716         memset(cmd, 0, MAX_COMMAND_SIZE);
1717         cmd[0] = WRITE_6;
1718         cmd[1] = (STp->block_size != 0);
1719
1720         STps->rw = ST_WRITING;
1721
1722         b_point = buf;
1723         while (count > 0 && !retry_eot) {
1724
1725                 if (STbp->do_dio) {
1726                         do_count = count;
1727                 }
1728                 else {
1729                         if (STp->block_size == 0)
1730                                 do_count = count;
1731                         else {
1732                                 do_count = STbp->buffer_blocks * STp->block_size -
1733                                         STbp->buffer_bytes;
1734                                 if (do_count > count)
1735                                         do_count = count;
1736                         }
1737
1738                         i = append_to_buffer(b_point, STbp, do_count);
1739                         if (i) {
1740                                 retval = i;
1741                                 goto out;
1742                         }
1743                 }
1744                 count -= do_count;
1745                 b_point += do_count;
1746
1747                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1748                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1749
1750                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1751                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1752                     STbp->buffer_bytes < STbp->buffer_size) {
1753                         STp->dirty = 1;
1754                         /* Don't write a buffer that is not full enough. */
1755                         if (!async_write && count == 0)
1756                                 break;
1757                 }
1758
1759         retry_write:
1760                 if (STp->block_size == 0)
1761                         blks = transfer = do_count;
1762                 else {
1763                         if (!STbp->do_dio)
1764                                 blks = STbp->buffer_bytes;
1765                         else
1766                                 blks = do_count;
1767                         blks /= STp->block_size;
1768                         transfer = blks * STp->block_size;
1769                 }
1770                 cmd[2] = blks >> 16;
1771                 cmd[3] = blks >> 8;
1772                 cmd[4] = blks;
1773
1774                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1775                                    STp->device->request_queue->rq_timeout,
1776                                    MAX_WRITE_RETRIES, !async_write);
1777                 if (!SRpnt) {
1778                         retval = STbp->syscall_result;
1779                         goto out;
1780                 }
1781                 if (async_write && !STbp->syscall_result) {
1782                         STbp->writing = transfer;
1783                         STp->dirty = !(STbp->writing ==
1784                                        STbp->buffer_bytes);
1785                         SRpnt = NULL;  /* Prevent releasing this request! */
1786                         DEB( STp->write_pending = 1; )
1787                         break;
1788                 }
1789
1790                 if (STbp->syscall_result != 0) {
1791                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1792
1793                         DEBC_printk(STp, "Error on write:\n");
1794                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1795                                 scode = cmdstatp->sense_hdr.sense_key;
1796                                 if (cmdstatp->remainder_valid)
1797                                         undone = (int)cmdstatp->uremainder64;
1798                                 else if (STp->block_size == 0 &&
1799                                          scode == VOLUME_OVERFLOW)
1800                                         undone = transfer;
1801                                 else
1802                                         undone = 0;
1803                                 if (STp->block_size != 0)
1804                                         undone *= STp->block_size;
1805                                 if (undone <= do_count) {
1806                                         /* Only data from this write is not written */
1807                                         count += undone;
1808                                         b_point -= undone;
1809                                         do_count -= undone;
1810                                         if (STp->block_size)
1811                                                 blks = (transfer - undone) / STp->block_size;
1812                                         STps->eof = ST_EOM_OK;
1813                                         /* Continue in fixed block mode if all written
1814                                            in this request but still something left to write
1815                                            (retval left to zero)
1816                                         */
1817                                         if (STp->block_size == 0 ||
1818                                             undone > 0 || count == 0)
1819                                                 retval = (-ENOSPC); /* EOM within current request */
1820                                         DEBC_printk(STp, "EOM with %d "
1821                                                     "bytes unwritten.\n",
1822                                                     (int)count);
1823                                 } else {
1824                                         /* EOT within data buffered earlier (possible only
1825                                            in fixed block mode without direct i/o) */
1826                                         if (!retry_eot && !cmdstatp->deferred &&
1827                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1828                                                 move_buffer_data(STp->buffer, transfer - undone);
1829                                                 retry_eot = 1;
1830                                                 if (STps->drv_block >= 0) {
1831                                                         STps->drv_block += (transfer - undone) /
1832                                                                 STp->block_size;
1833                                                 }
1834                                                 STps->eof = ST_EOM_OK;
1835                                                 DEBC_printk(STp, "Retry "
1836                                                             "write of %d "
1837                                                             "bytes at EOM.\n",
1838                                                             STp->buffer->buffer_bytes);
1839                                                 goto retry_write;
1840                                         }
1841                                         else {
1842                                                 /* Either error within data buffered by driver or
1843                                                    failed retry */
1844                                                 count -= do_count;
1845                                                 blks = do_count = 0;
1846                                                 STps->eof = ST_EOM_ERROR;
1847                                                 STps->drv_block = (-1); /* Too cautious? */
1848                                                 retval = (-EIO);        /* EOM for old data */
1849                                                 DEBC_printk(STp, "EOM with "
1850                                                             "lost data.\n");
1851                                         }
1852                                 }
1853                         } else {
1854                                 count += do_count;
1855                                 STps->drv_block = (-1);         /* Too cautious? */
1856                                 retval = STbp->syscall_result;
1857                         }
1858
1859                 }
1860
1861                 if (STps->drv_block >= 0) {
1862                         if (STp->block_size == 0)
1863                                 STps->drv_block += (do_count > 0);
1864                         else
1865                                 STps->drv_block += blks;
1866                 }
1867
1868                 STbp->buffer_bytes = 0;
1869                 STp->dirty = 0;
1870
1871                 if (retval || retry_eot) {
1872                         if (count < total)
1873                                 retval = total - count;
1874                         goto out;
1875                 }
1876         }
1877
1878         if (STps->eof == ST_EOD_1)
1879                 STps->eof = ST_EOM_OK;
1880         else if (STps->eof != ST_EOM_OK)
1881                 STps->eof = ST_NOEOF;
1882         retval = total - count;
1883
1884  out:
1885         if (SRpnt != NULL)
1886                 st_release_request(SRpnt);
1887         release_buffering(STp, 0);
1888         mutex_unlock(&STp->lock);
1889
1890         return retval;
1891 }
1892 \f
1893 /* Read data from the tape. Returns zero in the normal case, one if the
1894    eof status has changed, and the negative error code in case of a
1895    fatal error. Otherwise updates the buffer and the eof state.
1896
1897    Does release user buffer mapping if it is set.
1898 */
1899 static long read_tape(struct scsi_tape *STp, long count,
1900                       struct st_request ** aSRpnt)
1901 {
1902         int transfer, blks, bytes;
1903         unsigned char cmd[MAX_COMMAND_SIZE];
1904         struct st_request *SRpnt;
1905         struct st_modedef *STm;
1906         struct st_partstat *STps;
1907         struct st_buffer *STbp;
1908         int retval = 0;
1909
1910         if (count == 0)
1911                 return 0;
1912
1913         STm = &(STp->modes[STp->current_mode]);
1914         STps = &(STp->ps[STp->partition]);
1915         if (STps->eof == ST_FM_HIT)
1916                 return 1;
1917         STbp = STp->buffer;
1918
1919         if (STp->block_size == 0)
1920                 blks = bytes = count;
1921         else {
1922                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1923                         blks = (STp->buffer)->buffer_blocks;
1924                         bytes = blks * STp->block_size;
1925                 } else {
1926                         bytes = count;
1927                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1928                                 bytes = (STp->buffer)->buffer_size;
1929                         blks = bytes / STp->block_size;
1930                         bytes = blks * STp->block_size;
1931                 }
1932         }
1933
1934         memset(cmd, 0, MAX_COMMAND_SIZE);
1935         cmd[0] = READ_6;
1936         cmd[1] = (STp->block_size != 0);
1937         if (!cmd[1] && STp->sili)
1938                 cmd[1] |= 2;
1939         cmd[2] = blks >> 16;
1940         cmd[3] = blks >> 8;
1941         cmd[4] = blks;
1942
1943         SRpnt = *aSRpnt;
1944         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1945                            STp->device->request_queue->rq_timeout,
1946                            MAX_RETRIES, 1);
1947         release_buffering(STp, 1);
1948         *aSRpnt = SRpnt;
1949         if (!SRpnt)
1950                 return STbp->syscall_result;
1951
1952         STbp->read_pointer = 0;
1953         STps->at_sm = 0;
1954
1955         /* Something to check */
1956         if (STbp->syscall_result) {
1957                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1958
1959                 retval = 1;
1960                 DEBC_printk(STp,
1961                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1962                             SRpnt->sense[0], SRpnt->sense[1],
1963                             SRpnt->sense[2], SRpnt->sense[3],
1964                             SRpnt->sense[4], SRpnt->sense[5],
1965                             SRpnt->sense[6], SRpnt->sense[7]);
1966                 if (cmdstatp->have_sense) {
1967
1968                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1969                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1970
1971                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1972                                 /* Compute the residual count */
1973                                 if (cmdstatp->remainder_valid)
1974                                         transfer = (int)cmdstatp->uremainder64;
1975                                 else
1976                                         transfer = 0;
1977                                 if (STp->block_size == 0 &&
1978                                     cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR)
1979                                         transfer = bytes;
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 = cmd[2] & 0x80 ? 0xff000000 : 0;
2680         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2681         if (direction)
2682                 sc = -sc;
2683         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2684                   direction ? "backward" : "forward", sc, units);
2685 }
2686 #else
2687 #define ST_DEB_FORWARD  0
2688 #define ST_DEB_BACKWARD 1
2689 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2690 #endif
2691
2692
2693 /* Internal ioctl function */
2694 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2695 {
2696         int timeout;
2697         long ltmp;
2698         int ioctl_result;
2699         int chg_eof = 1;
2700         unsigned char cmd[MAX_COMMAND_SIZE];
2701         struct st_request *SRpnt;
2702         struct st_partstat *STps;
2703         int fileno, blkno, at_sm, undone;
2704         int datalen = 0, direction = DMA_NONE;
2705
2706         WARN_ON(STp->buffer->do_dio != 0);
2707         if (STp->ready != ST_READY) {
2708                 if (STp->ready == ST_NO_TAPE)
2709                         return (-ENOMEDIUM);
2710                 else
2711                         return (-EIO);
2712         }
2713         timeout = STp->long_timeout;
2714         STps = &(STp->ps[STp->partition]);
2715         fileno = STps->drv_file;
2716         blkno = STps->drv_block;
2717         at_sm = STps->at_sm;
2718
2719         memset(cmd, 0, MAX_COMMAND_SIZE);
2720         switch (cmd_in) {
2721         case MTFSFM:
2722                 chg_eof = 0;    /* Changed from the FSF after this */
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         case MTBSF:
2738                 cmd[0] = SPACE;
2739                 cmd[1] = 0x01;  /* Space FileMarks */
2740                 ltmp = (-arg);
2741                 cmd[2] = (ltmp >> 16);
2742                 cmd[3] = (ltmp >> 8);
2743                 cmd[4] = ltmp;
2744                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2745                 if (fileno >= 0)
2746                         fileno -= arg;
2747                 blkno = (-1);   /* We can't know the block number */
2748                 at_sm &= (arg == 0);
2749                 break;
2750         case MTFSR:
2751                 cmd[0] = SPACE;
2752                 cmd[1] = 0x00;  /* Space Blocks */
2753                 cmd[2] = (arg >> 16);
2754                 cmd[3] = (arg >> 8);
2755                 cmd[4] = arg;
2756                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2757                 if (blkno >= 0)
2758                         blkno += arg;
2759                 at_sm &= (arg == 0);
2760                 break;
2761         case MTBSR:
2762                 cmd[0] = SPACE;
2763                 cmd[1] = 0x00;  /* Space Blocks */
2764                 ltmp = (-arg);
2765                 cmd[2] = (ltmp >> 16);
2766                 cmd[3] = (ltmp >> 8);
2767                 cmd[4] = ltmp;
2768                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2769                 if (blkno >= 0)
2770                         blkno -= arg;
2771                 at_sm &= (arg == 0);
2772                 break;
2773         case MTFSS:
2774                 cmd[0] = SPACE;
2775                 cmd[1] = 0x04;  /* Space Setmarks */
2776                 cmd[2] = (arg >> 16);
2777                 cmd[3] = (arg >> 8);
2778                 cmd[4] = arg;
2779                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2780                 if (arg != 0) {
2781                         blkno = fileno = (-1);
2782                         at_sm = 1;
2783                 }
2784                 break;
2785         case MTBSS:
2786                 cmd[0] = SPACE;
2787                 cmd[1] = 0x04;  /* Space Setmarks */
2788                 ltmp = (-arg);
2789                 cmd[2] = (ltmp >> 16);
2790                 cmd[3] = (ltmp >> 8);
2791                 cmd[4] = ltmp;
2792                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2793                 if (arg != 0) {
2794                         blkno = fileno = (-1);
2795                         at_sm = 1;
2796                 }
2797                 break;
2798         case MTWEOF:
2799         case MTWEOFI:
2800         case MTWSM:
2801                 if (STp->write_prot)
2802                         return (-EACCES);
2803                 cmd[0] = WRITE_FILEMARKS;
2804                 if (cmd_in == MTWSM)
2805                         cmd[1] = 2;
2806                 if (cmd_in == MTWEOFI ||
2807                     (cmd_in == MTWEOF && STp->immediate_filemark))
2808                         cmd[1] |= 1;
2809                 cmd[2] = (arg >> 16);
2810                 cmd[3] = (arg >> 8);
2811                 cmd[4] = arg;
2812                 timeout = STp->device->request_queue->rq_timeout;
2813                 DEBC(
2814                         if (cmd_in != MTWSM)
2815                                 st_printk(ST_DEB_MSG, STp,
2816                                           "Writing %d filemarks.\n",
2817                                           cmd[2] * 65536 +
2818                                           cmd[3] * 256 +
2819                                           cmd[4]);
2820                         else
2821                                 st_printk(ST_DEB_MSG, STp,
2822                                           "Writing %d setmarks.\n",
2823                                           cmd[2] * 65536 +
2824                                           cmd[3] * 256 +
2825                                           cmd[4]);
2826                 )
2827                 if (fileno >= 0)
2828                         fileno += arg;
2829                 blkno = 0;
2830                 at_sm = (cmd_in == MTWSM);
2831                 break;
2832         case MTREW:
2833                 cmd[0] = REZERO_UNIT;
2834                 if (STp->immediate) {
2835                         cmd[1] = 1;     /* Don't wait for completion */
2836                         timeout = STp->device->request_queue->rq_timeout;
2837                 }
2838                 DEBC_printk(STp, "Rewinding tape.\n");
2839                 fileno = blkno = at_sm = 0;
2840                 break;
2841         case MTNOP:
2842                 DEBC_printk(STp, "No op on tape.\n");
2843                 return 0;       /* Should do something ? */
2844                 break;
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_MSK_PSUM_MB         0x10
3300
3301 /* Get the number of partitions on the tape. As a side effect reads the
3302    mode page into the tape buffer. */
3303 static int nbr_partitions(struct scsi_tape *STp)
3304 {
3305         int result;
3306
3307         if (STp->ready != ST_READY)
3308                 return (-EIO);
3309
3310         result = read_mode_page(STp, PART_PAGE, 1);
3311
3312         if (result) {
3313                 DEBC_printk(STp, "Can't read medium partition page.\n");
3314                 result = (-EIO);
3315         } else {
3316                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3317                                               PP_OFF_NBR_ADD_PARTS] + 1;
3318                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3319         }
3320
3321         return result;
3322 }
3323
3324
3325 /* Partition the tape into two partitions if size > 0 or one partition if
3326    size == 0.
3327
3328    The block descriptors are read and written because Sony SDT-7000 does not
3329    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3330
3331    My HP C1533A drive returns only one partition size field. This is used to
3332    set the size of partition 1. There is no size field for the default partition.
3333    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3334    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3335    The following algorithm is used to accommodate both drives: if the number of
3336    partition size fields is greater than the maximum number of additional partitions
3337    in the mode page, the second field is used. Otherwise the first field is used.
3338
3339    For Seagate DDS drives the page length must be 8 when no partitions is defined
3340    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3341    is acceptable also to some other old drives and enforced if the first partition
3342    size field is used for the first additional partition size.
3343  */
3344 static int partition_tape(struct scsi_tape *STp, int size)
3345 {
3346         int result;
3347         int pgo, psd_cnt, psdo;
3348         unsigned char *bp;
3349
3350         result = read_mode_page(STp, PART_PAGE, 0);
3351         if (result) {
3352                 DEBC_printk(STp, "Can't read partition mode page.\n");
3353                 return result;
3354         }
3355         /* The mode page is in the buffer. Let's modify it and write it. */
3356         bp = (STp->buffer)->b_data;
3357         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3358         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3359                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3360
3361         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3362         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3363         if (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS]) {
3364                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest of the tape */
3365                 psdo += 2;
3366         }
3367         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3368
3369         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3370                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3371                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3372
3373         if (size <= 0) {
3374                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3375                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3376                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3377                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3378         } else {
3379                 bp[psdo] = (size >> 8) & 0xff;
3380                 bp[psdo + 1] = size & 0xff;
3381                 bp[pgo + 3] = 1;
3382                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3383                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3384                 DEBC_printk(STp, "Formatting tape with two partitions "
3385                             "(1 = %d MB).\n", size);
3386         }
3387         bp[pgo + PP_OFF_PART_UNITS] = 0;
3388         bp[pgo + PP_OFF_RESERVED] = 0;
3389         bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | PP_MSK_PSUM_MB;
3390
3391         result = write_mode_page(STp, PART_PAGE, 1);
3392         if (result) {
3393                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3394                 result = (-EIO);
3395         }
3396
3397         return result;
3398 }
3399 \f
3400
3401
3402 /* The ioctl command */
3403 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3404 {
3405         int i, cmd_nr, cmd_type, bt;
3406         int retval = 0;
3407         unsigned int blk;
3408         struct scsi_tape *STp = file->private_data;
3409         struct st_modedef *STm;
3410         struct st_partstat *STps;
3411         void __user *p = (void __user *)arg;
3412
3413         if (mutex_lock_interruptible(&STp->lock))
3414                 return -ERESTARTSYS;
3415
3416         DEB(
3417         if (debugging && !STp->in_use) {
3418                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3419                 retval = (-EIO);
3420                 goto out;
3421         } ) /* end DEB */
3422
3423         STm = &(STp->modes[STp->current_mode]);
3424         STps = &(STp->ps[STp->partition]);
3425
3426         /*
3427          * If we are in the middle of error recovery, don't let anyone
3428          * else try and use this device.  Also, if error recovery fails, it
3429          * may try and take the device offline, in which case all further
3430          * access to the device is prohibited.
3431          */
3432         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3433                         file->f_flags & O_NDELAY);
3434         if (retval)
3435                 goto out;
3436
3437         cmd_type = _IOC_TYPE(cmd_in);
3438         cmd_nr = _IOC_NR(cmd_in);
3439
3440         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3441                 struct mtop mtc;
3442
3443                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3444                         retval = (-EINVAL);
3445                         goto out;
3446                 }
3447
3448                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3449                 if (i) {
3450                         retval = (-EFAULT);
3451                         goto out;
3452                 }
3453
3454                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3455                         st_printk(KERN_WARNING, STp,
3456                                   "MTSETDRVBUFFER only allowed for root.\n");
3457                         retval = (-EPERM);
3458                         goto out;
3459                 }
3460                 if (!STm->defined &&
3461                     (mtc.mt_op != MTSETDRVBUFFER &&
3462                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3463                         retval = (-ENXIO);
3464                         goto out;
3465                 }
3466
3467                 if (!STp->pos_unknown) {
3468
3469                         if (STps->eof == ST_FM_HIT) {
3470                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3471                                     mtc.mt_op == MTEOM) {
3472                                         mtc.mt_count -= 1;
3473                                         if (STps->drv_file >= 0)
3474                                                 STps->drv_file += 1;
3475                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3476                                         mtc.mt_count += 1;
3477                                         if (STps->drv_file >= 0)
3478                                                 STps->drv_file += 1;
3479                                 }
3480                         }
3481
3482                         if (mtc.mt_op == MTSEEK) {
3483                                 /* Old position must be restored if partition will be
3484                                    changed */
3485                                 i = !STp->can_partitions ||
3486                                     (STp->new_partition != STp->partition);
3487                         } else {
3488                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3489                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3490                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3491                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3492                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3493                                     mtc.mt_op == MTCOMPRESSION;
3494                         }
3495                         i = flush_buffer(STp, i);
3496                         if (i < 0) {
3497                                 retval = i;
3498                                 goto out;
3499                         }
3500                         if (STps->rw == ST_WRITING &&
3501                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3502                              mtc.mt_op == MTSEEK ||
3503                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3504                                 i = st_int_ioctl(STp, MTWEOF, 1);
3505                                 if (i < 0) {
3506                                         retval = i;
3507                                         goto out;
3508                                 }
3509                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3510                                         mtc.mt_count++;
3511                                 STps->rw = ST_IDLE;
3512                              }
3513
3514                 } else {
3515                         /*
3516                          * If there was a bus reset, block further access
3517                          * to this device.  If the user wants to rewind the tape,
3518                          * then reset the flag and allow access again.
3519                          */
3520                         if (mtc.mt_op != MTREW &&
3521                             mtc.mt_op != MTOFFL &&
3522                             mtc.mt_op != MTRETEN &&
3523                             mtc.mt_op != MTERASE &&
3524                             mtc.mt_op != MTSEEK &&
3525                             mtc.mt_op != MTEOM) {
3526                                 retval = (-EIO);
3527                                 goto out;
3528                         }
3529                         reset_state(STp);
3530                         /* remove this when the midlevel properly clears was_reset */
3531                         STp->device->was_reset = 0;
3532                 }
3533
3534                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3535                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3536                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3537                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3538
3539                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3540                         do_door_lock(STp, 0);   /* Ignore result! */
3541
3542                 if (mtc.mt_op == MTSETDRVBUFFER &&
3543                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3544                         retval = st_set_options(STp, mtc.mt_count);
3545                         goto out;
3546                 }
3547
3548                 if (mtc.mt_op == MTSETPART) {
3549                         if (!STp->can_partitions ||
3550                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3551                                 retval = (-EINVAL);
3552                                 goto out;
3553                         }
3554                         if (mtc.mt_count >= STp->nbr_partitions &&
3555                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3556                                 retval = (-EIO);
3557                                 goto out;
3558                         }
3559                         if (mtc.mt_count >= STp->nbr_partitions) {
3560                                 retval = (-EINVAL);
3561                                 goto out;
3562                         }
3563                         STp->new_partition = mtc.mt_count;
3564                         retval = 0;
3565                         goto out;
3566                 }
3567
3568                 if (mtc.mt_op == MTMKPART) {
3569                         if (!STp->can_partitions) {
3570                                 retval = (-EINVAL);
3571                                 goto out;
3572                         }
3573                         if ((i = st_int_ioctl(STp, MTREW, 0)) < 0 ||
3574                             (i = partition_tape(STp, mtc.mt_count)) < 0) {
3575                                 retval = i;
3576                                 goto out;
3577                         }
3578                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3579                                 STp->ps[i].rw = ST_IDLE;
3580                                 STp->ps[i].at_sm = 0;
3581                                 STp->ps[i].last_block_valid = 0;
3582                         }
3583                         STp->partition = STp->new_partition = 0;
3584                         STp->nbr_partitions = 1;        /* Bad guess ?-) */
3585                         STps->drv_block = STps->drv_file = 0;
3586                         retval = 0;
3587                         goto out;
3588                 }
3589
3590                 if (mtc.mt_op == MTSEEK) {
3591                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3592                         if (!STp->can_partitions)
3593                                 STp->ps[0].rw = ST_IDLE;
3594                         retval = i;
3595                         goto out;
3596                 }
3597
3598                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3599                         retval = do_load_unload(STp, file, 0);
3600                         goto out;
3601                 }
3602
3603                 if (mtc.mt_op == MTLOAD) {
3604                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3605                         goto out;
3606                 }
3607
3608                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3609                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3610                         goto out;
3611                 }
3612
3613                 if (STp->can_partitions && STp->ready == ST_READY &&
3614                     (i = switch_partition(STp)) < 0) {
3615                         retval = i;
3616                         goto out;
3617                 }
3618
3619                 if (mtc.mt_op == MTCOMPRESSION)
3620                         retval = st_compression(STp, (mtc.mt_count & 1));
3621                 else
3622                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3623                 goto out;
3624         }
3625         if (!STm->defined) {
3626                 retval = (-ENXIO);
3627                 goto out;
3628         }
3629
3630         if ((i = flush_buffer(STp, 0)) < 0) {
3631                 retval = i;
3632                 goto out;
3633         }
3634         if (STp->can_partitions &&
3635             (i = switch_partition(STp)) < 0) {
3636                 retval = i;
3637                 goto out;
3638         }
3639
3640         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3641                 struct mtget mt_status;
3642
3643                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3644                          retval = (-EINVAL);
3645                          goto out;
3646                 }
3647
3648                 mt_status.mt_type = STp->tape_type;
3649                 mt_status.mt_dsreg =
3650                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3651                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3652                 mt_status.mt_blkno = STps->drv_block;
3653                 mt_status.mt_fileno = STps->drv_file;
3654                 if (STp->block_size != 0) {
3655                         if (STps->rw == ST_WRITING)
3656                                 mt_status.mt_blkno +=
3657                                     (STp->buffer)->buffer_bytes / STp->block_size;
3658                         else if (STps->rw == ST_READING)
3659                                 mt_status.mt_blkno -=
3660                                         ((STp->buffer)->buffer_bytes +
3661                                          STp->block_size - 1) / STp->block_size;
3662                 }
3663
3664                 mt_status.mt_gstat = 0;
3665                 if (STp->drv_write_prot)
3666                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3667                 if (mt_status.mt_blkno == 0) {
3668                         if (mt_status.mt_fileno == 0)
3669                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3670                         else
3671                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3672                 }
3673                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3674                 mt_status.mt_resid = STp->partition;
3675                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3676                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3677                 else if (STps->eof >= ST_EOM_OK)
3678                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3679                 if (STp->density == 1)
3680                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3681                 else if (STp->density == 2)
3682                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3683                 else if (STp->density == 3)
3684                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3685                 if (STp->ready == ST_READY)
3686                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3687                 if (STp->ready == ST_NO_TAPE)
3688                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3689                 if (STps->at_sm)
3690                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3691                 if (STm->do_async_writes ||
3692                     (STm->do_buffer_writes && STp->block_size != 0) ||
3693                     STp->drv_buffer != 0)
3694                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3695                 if (STp->cleaning_req)
3696                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3697
3698                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3699                 if (i) {
3700                         retval = (-EFAULT);
3701                         goto out;
3702                 }
3703
3704                 STp->recover_reg = 0;           /* Clear after read */
3705                 retval = 0;
3706                 goto out;
3707         }                       /* End of MTIOCGET */
3708         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3709                 struct mtpos mt_pos;
3710                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3711                          retval = (-EINVAL);
3712                          goto out;
3713                 }
3714                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3715                         retval = i;
3716                         goto out;
3717                 }
3718                 mt_pos.mt_blkno = blk;
3719                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3720                 if (i)
3721                         retval = (-EFAULT);
3722                 goto out;
3723         }
3724         mutex_unlock(&STp->lock);
3725         switch (cmd_in) {
3726                 case SCSI_IOCTL_GET_IDLUN:
3727                 case SCSI_IOCTL_GET_BUS_NUMBER:
3728                         break;
3729                 default:
3730                         if ((cmd_in == SG_IO ||
3731                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3732                              cmd_in == CDROM_SEND_PACKET) &&
3733                             !capable(CAP_SYS_RAWIO))
3734                                 i = -EPERM;
3735                         else
3736                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3737                                                    file->f_mode, cmd_in, p);
3738                         if (i != -ENOTTY)
3739                                 return i;
3740                         break;
3741         }
3742         retval = scsi_ioctl(STp->device, cmd_in, p);
3743         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3744                 STp->rew_at_close = 0;
3745                 STp->ready = ST_NO_TAPE;
3746         }
3747         return retval;
3748
3749  out:
3750         mutex_unlock(&STp->lock);
3751         return retval;
3752 }
3753
3754 #ifdef CONFIG_COMPAT
3755 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3756 {
3757         struct scsi_tape *STp = file->private_data;
3758         struct scsi_device *sdev = STp->device;
3759         int ret = -ENOIOCTLCMD;
3760         if (sdev->host->hostt->compat_ioctl) {
3761
3762                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3763
3764         }
3765         return ret;
3766 }
3767 #endif
3768
3769 \f
3770
3771 /* Try to allocate a new tape buffer. Calling function must not hold
3772    dev_arr_lock. */
3773 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3774 {
3775         struct st_buffer *tb;
3776
3777         tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3778         if (!tb) {
3779                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3780                 return NULL;
3781         }
3782         tb->frp_segs = 0;
3783         tb->use_sg = max_sg;
3784         tb->dma = need_dma;
3785         tb->buffer_size = 0;
3786
3787         tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3788                                      GFP_ATOMIC);
3789         if (!tb->reserved_pages) {
3790                 kfree(tb);
3791                 return NULL;
3792         }
3793
3794         return tb;
3795 }
3796
3797
3798 /* Try to allocate enough space in the tape buffer */
3799 #define ST_MAX_ORDER 6
3800
3801 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3802 {
3803         int segs, max_segs, b_size, order, got;
3804         gfp_t priority;
3805
3806         if (new_size <= STbuffer->buffer_size)
3807                 return 1;
3808
3809         if (STbuffer->buffer_size <= PAGE_SIZE)
3810                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3811
3812         max_segs = STbuffer->use_sg;
3813
3814         priority = GFP_KERNEL | __GFP_NOWARN;
3815         if (need_dma)
3816                 priority |= GFP_DMA;
3817
3818         if (STbuffer->cleared)
3819                 priority |= __GFP_ZERO;
3820
3821         if (STbuffer->frp_segs) {
3822                 order = STbuffer->reserved_page_order;
3823                 b_size = PAGE_SIZE << order;
3824         } else {
3825                 for (b_size = PAGE_SIZE, order = 0;
3826                      order < ST_MAX_ORDER &&
3827                              max_segs * (PAGE_SIZE << order) < new_size;
3828                      order++, b_size *= 2)
3829                         ;  /* empty */
3830                 STbuffer->reserved_page_order = order;
3831         }
3832         if (max_segs * (PAGE_SIZE << order) < new_size) {
3833                 if (order == ST_MAX_ORDER)
3834                         return 0;
3835                 normalize_buffer(STbuffer);
3836                 return enlarge_buffer(STbuffer, new_size, need_dma);
3837         }
3838
3839         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3840              segs < max_segs && got < new_size;) {
3841                 struct page *page;
3842
3843                 page = alloc_pages(priority, order);
3844                 if (!page) {
3845                         DEB(STbuffer->buffer_size = got);
3846                         normalize_buffer(STbuffer);
3847                         return 0;
3848                 }
3849
3850                 STbuffer->frp_segs += 1;
3851                 got += b_size;
3852                 STbuffer->buffer_size = got;
3853                 STbuffer->reserved_pages[segs] = page;
3854                 segs++;
3855         }
3856         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3857
3858         return 1;
3859 }
3860
3861
3862 /* Make sure that no data from previous user is in the internal buffer */
3863 static void clear_buffer(struct st_buffer * st_bp)
3864 {
3865         int i;
3866
3867         for (i=0; i < st_bp->frp_segs; i++)
3868                 memset(page_address(st_bp->reserved_pages[i]), 0,
3869                        PAGE_SIZE << st_bp->reserved_page_order);
3870         st_bp->cleared = 1;
3871 }
3872
3873
3874 /* Release the extra buffer */
3875 static void normalize_buffer(struct st_buffer * STbuffer)
3876 {
3877         int i, order = STbuffer->reserved_page_order;
3878
3879         for (i = 0; i < STbuffer->frp_segs; i++) {
3880                 __free_pages(STbuffer->reserved_pages[i], order);
3881                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3882         }
3883         STbuffer->frp_segs = 0;
3884         STbuffer->sg_segs = 0;
3885         STbuffer->reserved_page_order = 0;
3886         STbuffer->map_data.offset = 0;
3887 }
3888
3889
3890 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3891    negative error code. */
3892 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3893 {
3894         int i, cnt, res, offset;
3895         int length = PAGE_SIZE << st_bp->reserved_page_order;
3896
3897         for (i = 0, offset = st_bp->buffer_bytes;
3898              i < st_bp->frp_segs && offset >= length; i++)
3899                 offset -= length;
3900         if (i == st_bp->frp_segs) {     /* Should never happen */
3901                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3902                 return (-EIO);
3903         }
3904         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3905                 struct page *page = st_bp->reserved_pages[i];
3906                 cnt = length - offset < do_count ? length - offset : do_count;
3907                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
3908                 if (res)
3909                         return (-EFAULT);
3910                 do_count -= cnt;
3911                 st_bp->buffer_bytes += cnt;
3912                 ubp += cnt;
3913                 offset = 0;
3914         }
3915         if (do_count) /* Should never happen */
3916                 return (-EIO);
3917
3918         return 0;
3919 }
3920
3921
3922 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
3923    negative error code. */
3924 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
3925 {
3926         int i, cnt, res, offset;
3927         int length = PAGE_SIZE << st_bp->reserved_page_order;
3928
3929         for (i = 0, offset = st_bp->read_pointer;
3930              i < st_bp->frp_segs && offset >= length; i++)
3931                 offset -= length;
3932         if (i == st_bp->frp_segs) {     /* Should never happen */
3933                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
3934                 return (-EIO);
3935         }
3936         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3937                 struct page *page = st_bp->reserved_pages[i];
3938                 cnt = length - offset < do_count ? length - offset : do_count;
3939                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
3940                 if (res)
3941                         return (-EFAULT);
3942                 do_count -= cnt;
3943                 st_bp->buffer_bytes -= cnt;
3944                 st_bp->read_pointer += cnt;
3945                 ubp += cnt;
3946                 offset = 0;
3947         }
3948         if (do_count) /* Should never happen */
3949                 return (-EIO);
3950
3951         return 0;
3952 }
3953
3954
3955 /* Move data towards start of buffer */
3956 static void move_buffer_data(struct st_buffer * st_bp, int offset)
3957 {
3958         int src_seg, dst_seg, src_offset = 0, dst_offset;
3959         int count, total;
3960         int length = PAGE_SIZE << st_bp->reserved_page_order;
3961
3962         if (offset == 0)
3963                 return;
3964
3965         total=st_bp->buffer_bytes - offset;
3966         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
3967                 src_offset = offset;
3968                 if (src_offset < length)
3969                         break;
3970                 offset -= length;
3971         }
3972
3973         st_bp->buffer_bytes = st_bp->read_pointer = total;
3974         for (dst_seg=dst_offset=0; total > 0; ) {
3975                 struct page *dpage = st_bp->reserved_pages[dst_seg];
3976                 struct page *spage = st_bp->reserved_pages[src_seg];
3977
3978                 count = min(length - dst_offset, length - src_offset);
3979                 memmove(page_address(dpage) + dst_offset,
3980                         page_address(spage) + src_offset, count);
3981                 src_offset += count;
3982                 if (src_offset >= length) {
3983                         src_seg++;
3984                         src_offset = 0;
3985                 }
3986                 dst_offset += count;
3987                 if (dst_offset >= length) {
3988                         dst_seg++;
3989                         dst_offset = 0;
3990                 }
3991                 total -= count;
3992         }
3993 }
3994
3995 /* Validate the options from command line or module parameters */
3996 static void validate_options(void)
3997 {
3998         if (buffer_kbs > 0)
3999                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4000         if (max_sg_segs >= ST_FIRST_SG)
4001                 st_max_sg_segs = max_sg_segs;
4002 }
4003
4004 #ifndef MODULE
4005 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4006  */
4007 static int __init st_setup(char *str)
4008 {
4009         int i, len, ints[5];
4010         char *stp;
4011
4012         stp = get_options(str, ARRAY_SIZE(ints), ints);
4013
4014         if (ints[0] > 0) {
4015                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4016                         if (parms[i].val)
4017                                 *parms[i].val = ints[i + 1];
4018         } else {
4019                 while (stp != NULL) {
4020                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4021                                 len = strlen(parms[i].name);
4022                                 if (!strncmp(stp, parms[i].name, len) &&
4023                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4024                                         if (parms[i].val)
4025                                                 *parms[i].val =
4026                                                         simple_strtoul(stp + len + 1, NULL, 0);
4027                                         else
4028                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4029                                                        parms[i].name);
4030                                         break;
4031                                 }
4032                         }
4033                         if (i >= ARRAY_SIZE(parms))
4034                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4035                                         stp);
4036                         stp = strchr(stp, ',');
4037                         if (stp)
4038                                 stp++;
4039                 }
4040         }
4041
4042         validate_options();
4043
4044         return 1;
4045 }
4046
4047 __setup("st=", st_setup);
4048
4049 #endif
4050
4051 static const struct file_operations st_fops =
4052 {
4053         .owner =        THIS_MODULE,
4054         .read =         st_read,
4055         .write =        st_write,
4056         .unlocked_ioctl = st_ioctl,
4057 #ifdef CONFIG_COMPAT
4058         .compat_ioctl = st_compat_ioctl,
4059 #endif
4060         .open =         st_open,
4061         .flush =        st_flush,
4062         .release =      st_release,
4063         .llseek =       noop_llseek,
4064 };
4065
4066 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4067 {
4068         int i, error;
4069         dev_t cdev_devno;
4070         struct cdev *cdev;
4071         struct device *dev;
4072         struct st_modedef *STm = &(tape->modes[mode]);
4073         char name[10];
4074         int dev_num = tape->index;
4075
4076         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4077
4078         cdev = cdev_alloc();
4079         if (!cdev) {
4080                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4081                 error = -ENOMEM;
4082                 goto out;
4083         }
4084         cdev->owner = THIS_MODULE;
4085         cdev->ops = &st_fops;
4086         STm->cdevs[rew] = cdev;
4087
4088         error = cdev_add(cdev, cdev_devno, 1);
4089         if (error) {
4090                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4091                        rew ? "non" : "auto", mode);
4092                 pr_err("st%d: Device not attached.\n", dev_num);
4093                 goto out_free;
4094         }
4095
4096         i = mode << (4 - ST_NBR_MODE_BITS);
4097         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4098                  tape->disk->disk_name, st_formats[i]);
4099
4100         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4101                             cdev_devno, &tape->modes[mode], "%s", name);
4102         if (IS_ERR(dev)) {
4103                 pr_err("st%d: device_create failed\n", dev_num);
4104                 error = PTR_ERR(dev);
4105                 goto out_free;
4106         }
4107
4108         STm->devs[rew] = dev;
4109
4110         return 0;
4111 out_free:
4112         cdev_del(STm->cdevs[rew]);
4113 out:
4114         STm->cdevs[rew] = NULL;
4115         STm->devs[rew] = NULL;
4116         return error;
4117 }
4118
4119 static int create_cdevs(struct scsi_tape *tape)
4120 {
4121         int mode, error;
4122         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4123                 error = create_one_cdev(tape, mode, 0);
4124                 if (error)
4125                         return error;
4126                 error = create_one_cdev(tape, mode, 1);
4127                 if (error)
4128                         return error;
4129         }
4130
4131         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4132                                  &tape->modes[0].devs[0]->kobj, "tape");
4133 }
4134
4135 static void remove_cdevs(struct scsi_tape *tape)
4136 {
4137         int mode, rew;
4138         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4139         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4140                 struct st_modedef *STm = &(tape->modes[mode]);
4141                 for (rew = 0; rew < 2; rew++) {
4142                         if (STm->cdevs[rew])
4143                                 cdev_del(STm->cdevs[rew]);
4144                         if (STm->devs[rew])
4145                                 device_unregister(STm->devs[rew]);
4146                 }
4147         }
4148 }
4149
4150 static int st_probe(struct device *dev)
4151 {
4152         struct scsi_device *SDp = to_scsi_device(dev);
4153         struct gendisk *disk = NULL;
4154         struct scsi_tape *tpnt = NULL;
4155         struct st_modedef *STm;
4156         struct st_partstat *STps;
4157         struct st_buffer *buffer;
4158         int i, error;
4159         char *stp;
4160
4161         if (SDp->type != TYPE_TAPE)
4162                 return -ENODEV;
4163         if ((stp = st_incompatible(SDp))) {
4164                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4165                 sdev_printk(KERN_INFO, SDp,
4166                             "st: The suggested driver is %s.\n", stp);
4167                 return -ENODEV;
4168         }
4169
4170         scsi_autopm_get_device(SDp);
4171         i = queue_max_segments(SDp->request_queue);
4172         if (st_max_sg_segs < i)
4173                 i = st_max_sg_segs;
4174         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4175         if (buffer == NULL) {
4176                 sdev_printk(KERN_ERR, SDp,
4177                             "st: Can't allocate new tape buffer. "
4178                             "Device not attached.\n");
4179                 goto out;
4180         }
4181
4182         disk = alloc_disk(1);
4183         if (!disk) {
4184                 sdev_printk(KERN_ERR, SDp,
4185                             "st: out of memory. Device not attached.\n");
4186                 goto out_buffer_free;
4187         }
4188
4189         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4190         if (tpnt == NULL) {
4191                 sdev_printk(KERN_ERR, SDp,
4192                             "st: Can't allocate device descriptor.\n");
4193                 goto out_put_disk;
4194         }
4195         kref_init(&tpnt->kref);
4196         tpnt->disk = disk;
4197         disk->private_data = &tpnt->driver;
4198         disk->queue = SDp->request_queue;
4199         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4200          * take queue reference that release_disk() expects. */
4201         if (!blk_get_queue(disk->queue))
4202                 goto out_put_disk;
4203         tpnt->driver = &st_template;
4204
4205         tpnt->device = SDp;
4206         if (SDp->scsi_level <= 2)
4207                 tpnt->tape_type = MT_ISSCSI1;
4208         else
4209                 tpnt->tape_type = MT_ISSCSI2;
4210
4211         tpnt->buffer = buffer;
4212         tpnt->buffer->last_SRpnt = NULL;
4213
4214         tpnt->inited = 0;
4215         tpnt->dirty = 0;
4216         tpnt->in_use = 0;
4217         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4218         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4219         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4220         tpnt->density = 0;
4221         tpnt->do_auto_lock = ST_AUTO_LOCK;
4222         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4223         tpnt->can_partitions = 0;
4224         tpnt->two_fm = ST_TWO_FM;
4225         tpnt->fast_mteom = ST_FAST_MTEOM;
4226         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4227         tpnt->sili = ST_SILI;
4228         tpnt->immediate = ST_NOWAIT;
4229         tpnt->immediate_filemark = 0;
4230         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4231         tpnt->partition = 0;
4232         tpnt->new_partition = 0;
4233         tpnt->nbr_partitions = 0;
4234         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4235         tpnt->long_timeout = ST_LONG_TIMEOUT;
4236         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4237
4238         for (i = 0; i < ST_NBR_MODES; i++) {
4239                 STm = &(tpnt->modes[i]);
4240                 STm->defined = 0;
4241                 STm->sysv = ST_SYSV;
4242                 STm->defaults_for_writes = 0;
4243                 STm->do_async_writes = ST_ASYNC_WRITES;
4244                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4245                 STm->do_read_ahead = ST_READ_AHEAD;
4246                 STm->default_compression = ST_DONT_TOUCH;
4247                 STm->default_blksize = (-1);    /* No forced size */
4248                 STm->default_density = (-1);    /* No forced density */
4249                 STm->tape = tpnt;
4250         }
4251
4252         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4253                 STps = &(tpnt->ps[i]);
4254                 STps->rw = ST_IDLE;
4255                 STps->eof = ST_NOEOF;
4256                 STps->at_sm = 0;
4257                 STps->last_block_valid = 0;
4258                 STps->drv_block = (-1);
4259                 STps->drv_file = (-1);
4260         }
4261
4262         tpnt->current_mode = 0;
4263         tpnt->modes[0].defined = 1;
4264
4265         tpnt->density_changed = tpnt->compression_changed =
4266             tpnt->blksize_changed = 0;
4267         mutex_init(&tpnt->lock);
4268
4269         idr_preload(GFP_KERNEL);
4270         spin_lock(&st_index_lock);
4271         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4272         spin_unlock(&st_index_lock);
4273         idr_preload_end();
4274         if (error < 0) {
4275                 pr_warn("st: idr allocation failed: %d\n", error);
4276                 goto out_put_queue;
4277         }
4278         tpnt->index = error;
4279         sprintf(disk->disk_name, "st%d", tpnt->index);
4280         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4281         if (tpnt->stats == NULL) {
4282                 sdev_printk(KERN_ERR, SDp,
4283                             "st: Can't allocate statistics.\n");
4284                 goto out_idr_remove;
4285         }
4286
4287         dev_set_drvdata(dev, tpnt);
4288
4289
4290         error = create_cdevs(tpnt);
4291         if (error)
4292                 goto out_remove_devs;
4293         scsi_autopm_put_device(SDp);
4294
4295         sdev_printk(KERN_NOTICE, SDp,
4296                     "Attached scsi tape %s\n", tape_name(tpnt));
4297         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4298                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4299                     queue_dma_alignment(SDp->request_queue) + 1);
4300
4301         return 0;
4302
4303 out_remove_devs:
4304         remove_cdevs(tpnt);
4305         kfree(tpnt->stats);
4306 out_idr_remove:
4307         spin_lock(&st_index_lock);
4308         idr_remove(&st_index_idr, tpnt->index);
4309         spin_unlock(&st_index_lock);
4310 out_put_queue:
4311         blk_put_queue(disk->queue);
4312 out_put_disk:
4313         put_disk(disk);
4314         kfree(tpnt);
4315 out_buffer_free:
4316         kfree(buffer);
4317 out:
4318         scsi_autopm_put_device(SDp);
4319         return -ENODEV;
4320 };
4321
4322
4323 static int st_remove(struct device *dev)
4324 {
4325         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4326         int index = tpnt->index;
4327
4328         scsi_autopm_get_device(to_scsi_device(dev));
4329         remove_cdevs(tpnt);
4330
4331         mutex_lock(&st_ref_mutex);
4332         kref_put(&tpnt->kref, scsi_tape_release);
4333         mutex_unlock(&st_ref_mutex);
4334         spin_lock(&st_index_lock);
4335         idr_remove(&st_index_idr, index);
4336         spin_unlock(&st_index_lock);
4337         return 0;
4338 }
4339
4340 /**
4341  *      scsi_tape_release - Called to free the Scsi_Tape structure
4342  *      @kref: pointer to embedded kref
4343  *
4344  *      st_ref_mutex must be held entering this routine.  Because it is
4345  *      called on last put, you should always use the scsi_tape_get()
4346  *      scsi_tape_put() helpers which manipulate the semaphore directly
4347  *      and never do a direct kref_put().
4348  **/
4349 static void scsi_tape_release(struct kref *kref)
4350 {
4351         struct scsi_tape *tpnt = to_scsi_tape(kref);
4352         struct gendisk *disk = tpnt->disk;
4353
4354         tpnt->device = NULL;
4355
4356         if (tpnt->buffer) {
4357                 normalize_buffer(tpnt->buffer);
4358                 kfree(tpnt->buffer->reserved_pages);
4359                 kfree(tpnt->buffer);
4360         }
4361
4362         disk->private_data = NULL;
4363         put_disk(disk);
4364         kfree(tpnt->stats);
4365         kfree(tpnt);
4366         return;
4367 }
4368
4369 static struct class st_sysfs_class = {
4370         .name = "scsi_tape",
4371         .dev_groups = st_dev_groups,
4372 };
4373
4374 static int __init init_st(void)
4375 {
4376         int err;
4377
4378         validate_options();
4379
4380         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4381                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4382
4383         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4384         if (debugging) {
4385                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4386                         debugging);
4387         }
4388
4389         err = class_register(&st_sysfs_class);
4390         if (err) {
4391                 pr_err("Unable register sysfs class for SCSI tapes\n");
4392                 return err;
4393         }
4394
4395         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4396                                      ST_MAX_TAPE_ENTRIES, "st");
4397         if (err) {
4398                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4399                        SCSI_TAPE_MAJOR);
4400                 goto err_class;
4401         }
4402
4403         err = scsi_register_driver(&st_template.gendrv);
4404         if (err)
4405                 goto err_chrdev;
4406
4407         return 0;
4408
4409 err_chrdev:
4410         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4411                                  ST_MAX_TAPE_ENTRIES);
4412 err_class:
4413         class_unregister(&st_sysfs_class);
4414         return err;
4415 }
4416
4417 static void __exit exit_st(void)
4418 {
4419         scsi_unregister_driver(&st_template.gendrv);
4420         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4421                                  ST_MAX_TAPE_ENTRIES);
4422         class_unregister(&st_sysfs_class);
4423         idr_destroy(&st_index_idr);
4424         printk(KERN_INFO "st: Unloaded.\n");
4425 }
4426
4427 module_init(init_st);
4428 module_exit(exit_st);
4429
4430
4431 /* The sysfs driver interface. Read-only at the moment */
4432 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4433 {
4434         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4435 }
4436 static DRIVER_ATTR_RO(try_direct_io);
4437
4438 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4439 {
4440         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4441 }
4442 static DRIVER_ATTR_RO(fixed_buffer_size);
4443
4444 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4445 {
4446         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4447 }
4448 static DRIVER_ATTR_RO(max_sg_segs);
4449
4450 static ssize_t version_show(struct device_driver *ddd, char *buf)
4451 {
4452         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4453 }
4454 static DRIVER_ATTR_RO(version);
4455
4456 #if DEBUG
4457 static ssize_t debug_flag_store(struct device_driver *ddp,
4458         const char *buf, size_t count)
4459 {
4460 /* We only care what the first byte of the data is the rest is unused.
4461  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4462  * other values have -EINVAL returned if they are passed in.
4463  */
4464         if (count > 0) {
4465                 if (buf[0] == '0') {
4466                         debugging = NO_DEBUG;
4467                         return count;
4468                 } else if (buf[0] == '1') {
4469                         debugging = 1;
4470                         return count;
4471                 }
4472         }
4473         return -EINVAL;
4474 }
4475
4476 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4477 {
4478         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4479 }
4480 static DRIVER_ATTR_RW(debug_flag);
4481 #endif
4482
4483 static struct attribute *st_drv_attrs[] = {
4484         &driver_attr_try_direct_io.attr,
4485         &driver_attr_fixed_buffer_size.attr,
4486         &driver_attr_max_sg_segs.attr,
4487         &driver_attr_version.attr,
4488 #if DEBUG
4489         &driver_attr_debug_flag.attr,
4490 #endif
4491         NULL,
4492 };
4493 ATTRIBUTE_GROUPS(st_drv);
4494
4495 /* The sysfs simple class interface */
4496 static ssize_t
4497 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4498 {
4499         struct st_modedef *STm = dev_get_drvdata(dev);
4500         ssize_t l = 0;
4501
4502         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4503         return l;
4504 }
4505 static DEVICE_ATTR_RO(defined);
4506
4507 static ssize_t
4508 default_blksize_show(struct device *dev, struct device_attribute *attr,
4509                      char *buf)
4510 {
4511         struct st_modedef *STm = dev_get_drvdata(dev);
4512         ssize_t l = 0;
4513
4514         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4515         return l;
4516 }
4517 static DEVICE_ATTR_RO(default_blksize);
4518
4519 static ssize_t
4520 default_density_show(struct device *dev, struct device_attribute *attr,
4521                      char *buf)
4522 {
4523         struct st_modedef *STm = dev_get_drvdata(dev);
4524         ssize_t l = 0;
4525         char *fmt;
4526
4527         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4528         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4529         return l;
4530 }
4531 static DEVICE_ATTR_RO(default_density);
4532
4533 static ssize_t
4534 default_compression_show(struct device *dev, struct device_attribute *attr,
4535                          char *buf)
4536 {
4537         struct st_modedef *STm = dev_get_drvdata(dev);
4538         ssize_t l = 0;
4539
4540         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4541         return l;
4542 }
4543 static DEVICE_ATTR_RO(default_compression);
4544
4545 static ssize_t
4546 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4547 {
4548         struct st_modedef *STm = dev_get_drvdata(dev);
4549         struct scsi_tape *STp = STm->tape;
4550         int options;
4551         ssize_t l = 0;
4552
4553         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4554         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4555         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4556         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4557         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4558         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4559         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4560         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4561         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4562         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4563         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4564         options |= STm->sysv ? MT_ST_SYSV : 0;
4565         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4566         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4567         options |= STp->sili ? MT_ST_SILI : 0;
4568
4569         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4570         return l;
4571 }
4572 static DEVICE_ATTR_RO(options);
4573
4574 /* Support for tape stats */
4575
4576 /**
4577  * read_cnt_show - return read count - count of reads made from tape drive
4578  * @dev: struct device
4579  * @attr: attribute structure
4580  * @buf: buffer to return formatted data in
4581  */
4582 static ssize_t read_cnt_show(struct device *dev,
4583         struct device_attribute *attr, char *buf)
4584 {
4585         struct st_modedef *STm = dev_get_drvdata(dev);
4586
4587         return sprintf(buf, "%lld",
4588                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4589 }
4590 static DEVICE_ATTR_RO(read_cnt);
4591
4592 /**
4593  * read_byte_cnt_show - return read byte count - tape drives
4594  * may use blocks less than 512 bytes this gives the raw byte count of
4595  * of data read from the tape drive.
4596  * @dev: struct device
4597  * @attr: attribute structure
4598  * @buf: buffer to return formatted data in
4599  */
4600 static ssize_t read_byte_cnt_show(struct device *dev,
4601         struct device_attribute *attr, char *buf)
4602 {
4603         struct st_modedef *STm = dev_get_drvdata(dev);
4604
4605         return sprintf(buf, "%lld",
4606                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4607 }
4608 static DEVICE_ATTR_RO(read_byte_cnt);
4609
4610 /**
4611  * read_us_show - return read us - overall time spent waiting on reads in ns.
4612  * @dev: struct device
4613  * @attr: attribute structure
4614  * @buf: buffer to return formatted data in
4615  */
4616 static ssize_t read_ns_show(struct device *dev,
4617         struct device_attribute *attr, char *buf)
4618 {
4619         struct st_modedef *STm = dev_get_drvdata(dev);
4620
4621         return sprintf(buf, "%lld",
4622                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4623 }
4624 static DEVICE_ATTR_RO(read_ns);
4625
4626 /**
4627  * write_cnt_show - write count - number of user calls
4628  * to write(2) that have written data to tape.
4629  * @dev: struct device
4630  * @attr: attribute structure
4631  * @buf: buffer to return formatted data in
4632  */
4633 static ssize_t write_cnt_show(struct device *dev,
4634         struct device_attribute *attr, char *buf)
4635 {
4636         struct st_modedef *STm = dev_get_drvdata(dev);
4637
4638         return sprintf(buf, "%lld",
4639                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4640 }
4641 static DEVICE_ATTR_RO(write_cnt);
4642
4643 /**
4644  * write_byte_cnt_show - write byte count - raw count of
4645  * bytes written to tape.
4646  * @dev: struct device
4647  * @attr: attribute structure
4648  * @buf: buffer to return formatted data in
4649  */
4650 static ssize_t write_byte_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->write_byte_cnt));
4657 }
4658 static DEVICE_ATTR_RO(write_byte_cnt);
4659
4660 /**
4661  * write_ns_show - write ns - number of nanoseconds waiting on write
4662  * requests to complete.
4663  * @dev: struct device
4664  * @attr: attribute structure
4665  * @buf: buffer to return formatted data in
4666  */
4667 static ssize_t write_ns_show(struct device *dev,
4668         struct device_attribute *attr, char *buf)
4669 {
4670         struct st_modedef *STm = dev_get_drvdata(dev);
4671
4672         return sprintf(buf, "%lld",
4673                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4674 }
4675 static DEVICE_ATTR_RO(write_ns);
4676
4677 /**
4678  * in_flight_show - number of I/Os currently in flight -
4679  * in most cases this will be either 0 or 1. It may be higher if someone
4680  * has also issued other SCSI commands such as via an ioctl.
4681  * @dev: struct device
4682  * @attr: attribute structure
4683  * @buf: buffer to return formatted data in
4684  */
4685 static ssize_t in_flight_show(struct device *dev,
4686         struct device_attribute *attr, char *buf)
4687 {
4688         struct st_modedef *STm = dev_get_drvdata(dev);
4689
4690         return sprintf(buf, "%lld",
4691                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4692 }
4693 static DEVICE_ATTR_RO(in_flight);
4694
4695 /**
4696  * io_ns_show - io wait ns - this is the number of ns spent
4697  * waiting on all I/O to complete. This includes tape movement commands
4698  * such as rewinding, seeking to end of file or tape, it also includes
4699  * read and write. To determine the time spent on tape movement
4700  * subtract the read and write ns from this value.
4701  * @dev: struct device
4702  * @attr: attribute structure
4703  * @buf: buffer to return formatted data in
4704  */
4705 static ssize_t io_ns_show(struct device *dev,
4706         struct device_attribute *attr, char *buf)
4707 {
4708         struct st_modedef *STm = dev_get_drvdata(dev);
4709
4710         return sprintf(buf, "%lld",
4711                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4712 }
4713 static DEVICE_ATTR_RO(io_ns);
4714
4715 /**
4716  * other_cnt_show - other io count - this is the number of
4717  * I/O requests other than read and write requests.
4718  * Typically these are tape movement requests but will include driver
4719  * tape movement. This includes only requests issued by the st driver.
4720  * @dev: struct device
4721  * @attr: attribute structure
4722  * @buf: buffer to return formatted data in
4723  */
4724 static ssize_t other_cnt_show(struct device *dev,
4725         struct device_attribute *attr, char *buf)
4726 {
4727         struct st_modedef *STm = dev_get_drvdata(dev);
4728
4729         return sprintf(buf, "%lld",
4730                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4731 }
4732 static DEVICE_ATTR_RO(other_cnt);
4733
4734 /**
4735  * resid_cnt_show - A count of the number of times we get a residual
4736  * count - this should indicate someone issuing reads larger than the
4737  * block size on tape.
4738  * @dev: struct device
4739  * @attr: attribute structure
4740  * @buf: buffer to return formatted data in
4741  */
4742 static ssize_t resid_cnt_show(struct device *dev,
4743         struct device_attribute *attr, char *buf)
4744 {
4745         struct st_modedef *STm = dev_get_drvdata(dev);
4746
4747         return sprintf(buf, "%lld",
4748                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4749 }
4750 static DEVICE_ATTR_RO(resid_cnt);
4751
4752 static struct attribute *st_dev_attrs[] = {
4753         &dev_attr_defined.attr,
4754         &dev_attr_default_blksize.attr,
4755         &dev_attr_default_density.attr,
4756         &dev_attr_default_compression.attr,
4757         &dev_attr_options.attr,
4758         NULL,
4759 };
4760
4761 static struct attribute *st_stats_attrs[] = {
4762         &dev_attr_read_cnt.attr,
4763         &dev_attr_read_byte_cnt.attr,
4764         &dev_attr_read_ns.attr,
4765         &dev_attr_write_cnt.attr,
4766         &dev_attr_write_byte_cnt.attr,
4767         &dev_attr_write_ns.attr,
4768         &dev_attr_in_flight.attr,
4769         &dev_attr_io_ns.attr,
4770         &dev_attr_other_cnt.attr,
4771         &dev_attr_resid_cnt.attr,
4772         NULL,
4773 };
4774
4775 static struct attribute_group stats_group = {
4776         .name = "stats",
4777         .attrs = st_stats_attrs,
4778 };
4779
4780 static struct attribute_group st_group = {
4781         .attrs = st_dev_attrs,
4782 };
4783
4784 static const struct attribute_group *st_dev_groups[] = {
4785         &st_group,
4786         &stats_group,
4787         NULL,
4788 };
4789
4790 /* The following functions may be useful for a larger audience. */
4791 static int sgl_map_user_pages(struct st_buffer *STbp,
4792                               const unsigned int max_pages, unsigned long uaddr,
4793                               size_t count, int rw)
4794 {
4795         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4796         unsigned long start = uaddr >> PAGE_SHIFT;
4797         const int nr_pages = end - start;
4798         int res, i, j;
4799         struct page **pages;
4800         struct rq_map_data *mdata = &STbp->map_data;
4801
4802         /* User attempted Overflow! */
4803         if ((uaddr + count) < uaddr)
4804                 return -EINVAL;
4805
4806         /* Too big */
4807         if (nr_pages > max_pages)
4808                 return -ENOMEM;
4809
4810         /* Hmm? */
4811         if (count == 0)
4812                 return 0;
4813
4814         if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4815                 return -ENOMEM;
4816
4817         /* Try to fault in all of the necessary pages */
4818         /* rw==READ means read from drive, write into memory area */
4819         res = get_user_pages_unlocked(
4820                 current,
4821                 current->mm,
4822                 uaddr,
4823                 nr_pages,
4824                 rw == READ,
4825                 0, /* don't force */
4826                 pages);
4827
4828         /* Errors and no page mapped should return here */
4829         if (res < nr_pages)
4830                 goto out_unmap;
4831
4832         for (i=0; i < nr_pages; i++) {
4833                 /* FIXME: flush superflous for rw==READ,
4834                  * probably wrong function for rw==WRITE
4835                  */
4836                 flush_dcache_page(pages[i]);
4837         }
4838
4839         mdata->offset = uaddr & ~PAGE_MASK;
4840         STbp->mapped_pages = pages;
4841
4842         return nr_pages;
4843  out_unmap:
4844         if (res > 0) {
4845                 for (j=0; j < res; j++)
4846                         page_cache_release(pages[j]);
4847                 res = 0;
4848         }
4849         kfree(pages);
4850         return res;
4851 }
4852
4853
4854 /* And unmap them... */
4855 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4856                                 const unsigned int nr_pages, int dirtied)
4857 {
4858         int i;
4859
4860         for (i=0; i < nr_pages; i++) {
4861                 struct page *page = STbp->mapped_pages[i];
4862
4863                 if (dirtied)
4864                         SetPageDirty(page);
4865                 /* FIXME: cache flush missing for rw==READ
4866                  * FIXME: call the correct reference counting function
4867                  */
4868                 page_cache_release(page);
4869         }
4870         kfree(STbp->mapped_pages);
4871         STbp->mapped_pages = NULL;
4872
4873         return 0;
4874 }