git.oblomov.eu Git - linux-2.6/blob - drivers/ide/ide-tape.c

   1 /*
   2  * IDE ATAPI streaming tape driver.
   3  *
   4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
   5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
   6  *
   7  * This driver was constructed as a student project in the software laboratory
   8  * of the faculty of electrical engineering in the Technion - Israel's
   9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
  10  *
  11  * It is hereby placed under the terms of the GNU general public license.
  12  * (See linux/COPYING).
  13  *
  14  * For a historical changelog see
  15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
  16  */
  17
  18 #define DRV_NAME "ide-tape"
  19
  20 #define IDETAPE_VERSION "1.20"
  21
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/string.h>
  25 #include <linux/kernel.h>
  26 #include <linux/delay.h>
  27 #include <linux/timer.h>
  28 #include <linux/mm.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/major.h>
  32 #include <linux/errno.h>
  33 #include <linux/genhd.h>
  34 #include <linux/slab.h>
  35 #include <linux/pci.h>
  36 #include <linux/ide.h>
  37 #include <linux/smp_lock.h>
  38 #include <linux/completion.h>
  39 #include <linux/bitops.h>
  40 #include <linux/mutex.h>
  41 #include <scsi/scsi.h>
  42
  43 #include <asm/byteorder.h>
  44 #include <linux/irq.h>
  45 #include <linux/uaccess.h>
  46 #include <linux/io.h>
  47 #include <asm/unaligned.h>
  48 #include <linux/mtio.h>
  49
  50 enum {
  51         /* output errors only */
  52         DBG_ERR =               (1 << 0),
  53         /* output all sense key/asc */
  54         DBG_SENSE =             (1 << 1),
  55         /* info regarding all chrdev-related procedures */
  56         DBG_CHRDEV =            (1 << 2),
  57         /* all remaining procedures */
  58         DBG_PROCS =             (1 << 3),
  59 };
  60
  61 /* define to see debug info */
  62 #define IDETAPE_DEBUG_LOG               0
  63
  64 #if IDETAPE_DEBUG_LOG
  65 #define debug_log(lvl, fmt, args...)                    \
  66 {                                                       \
  67         if (tape->debug_mask & lvl)                     \
  68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
  69 }
  70 #else
  71 #define debug_log(lvl, fmt, args...) do {} while (0)
  72 #endif
  73
  74 /**************************** Tunable parameters *****************************/
  75 /*
  76  * After each failed packet command we issue a request sense command and retry
  77  * the packet command IDETAPE_MAX_PC_RETRIES times.
  78  *
  79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
  80  */
  81 #define IDETAPE_MAX_PC_RETRIES          3
  82
  83 /*
  84  * The following parameter is used to select the point in the internal tape fifo
  85  * in which we will start to refill the buffer. Decreasing the following
  86  * parameter will improve the system's latency and interactive response, while
  87  * using a high value might improve system throughput.
  88  */
  89 #define IDETAPE_FIFO_THRESHOLD          2
  90
  91 /*
  92  * DSC polling parameters.
  93  *
  94  * Polling for DSC (a single bit in the status register) is a very important
  95  * function in ide-tape. There are two cases in which we poll for DSC:
  96  *
  97  * 1. Before a read/write packet command, to ensure that we can transfer data
  98  * from/to the tape's data buffers, without causing an actual media access.
  99  * In case the tape is not ready yet, we take out our request from the device
 100  * request queue, so that ide.c could service requests from the other device
 101  * on the same interface in the meantime.
 102  *
 103  * 2. After the successful initialization of a "media access packet command",
 104  * which is a command that can take a long time to complete (the interval can
 105  * range from several seconds to even an hour). Again, we postpone our request
 106  * in the middle to free the bus for the other device. The polling frequency
 107  * here should be lower than the read/write frequency since those media access
 108  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 109  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 110  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
 111  *
 112  * We also set a timeout for the timer, in case something goes wrong. The
 113  * timeout should be longer then the maximum execution time of a tape operation.
 114  */
 115
 116 /* DSC timings. */
 117 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 118 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 119 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 120 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 121 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 122 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 123 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 124
 125 /*************************** End of tunable parameters ***********************/
 126
 127 /* tape directions */
 128 enum {
 129         IDETAPE_DIR_NONE  = (1 << 0),
 130         IDETAPE_DIR_READ  = (1 << 1),
 131         IDETAPE_DIR_WRITE = (1 << 2),
 132 };
 133
 134 struct idetape_bh {
 135         u32 b_size;
 136         atomic_t b_count;
 137         struct idetape_bh *b_reqnext;
 138         char *b_data;
 139 };
 140
 141 /* Tape door status */
 142 #define DOOR_UNLOCKED                   0
 143 #define DOOR_LOCKED                     1
 144 #define DOOR_EXPLICITLY_LOCKED          2
 145
 146 /* Some defines for the SPACE command */
 147 #define IDETAPE_SPACE_OVER_FILEMARK     1
 148 #define IDETAPE_SPACE_TO_EOD            3
 149
 150 /* Some defines for the LOAD UNLOAD command */
 151 #define IDETAPE_LU_LOAD_MASK            1
 152 #define IDETAPE_LU_RETENSION_MASK       2
 153 #define IDETAPE_LU_EOT_MASK             4
 154
 155 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
 156 #define IDETAPE_BLOCK_DESCRIPTOR        0
 157 #define IDETAPE_CAPABILITIES_PAGE       0x2a
 158
 159 /*
 160  * Most of our global data which we need to save even as we leave the driver due
 161  * to an interrupt or a timer event is stored in the struct defined below.
 162  */
 163 typedef struct ide_tape_obj {
 164         ide_drive_t             *drive;
 165         struct ide_driver       *driver;
 166         struct gendisk          *disk;
 167         struct device           dev;
 168
 169         /* used by REQ_IDETAPE_{READ,WRITE} requests */
 170         struct ide_atapi_pc queued_pc;
 171
 172         /*
 173          * DSC polling variables.
 174          *
 175          * While polling for DSC we use postponed_rq to postpone the current
 176          * request so that ide.c will be able to service pending requests on the
 177          * other device. Note that at most we will have only one DSC (usually
 178          * data transfer) request in the device request queue.
 179          */
 180         struct request *postponed_rq;
 181         /* The time in which we started polling for DSC */
 182         unsigned long dsc_polling_start;
 183         /* Timer used to poll for dsc */
 184         struct timer_list dsc_timer;
 185         /* Read/Write dsc polling frequency */
 186         unsigned long best_dsc_rw_freq;
 187         unsigned long dsc_poll_freq;
 188         unsigned long dsc_timeout;
 189
 190         /* Read position information */
 191         u8 partition;
 192         /* Current block */
 193         unsigned int first_frame;
 194
 195         /* Last error information */
 196         u8 sense_key, asc, ascq;
 197
 198         /* Character device operation */
 199         unsigned int minor;
 200         /* device name */
 201         char name[4];
 202         /* Current character device data transfer direction */
 203         u8 chrdev_dir;
 204
 205         /* tape block size, usually 512 or 1024 bytes */
 206         unsigned short blk_size;
 207         int user_bs_factor;
 208
 209         /* Copy of the tape's Capabilities and Mechanical Page */
 210         u8 caps[20];
 211
 212         /*
 213          * Active data transfer request parameters.
 214          *
 215          * At most, there is only one ide-tape originated data transfer request
 216          * in the device request queue. This allows ide.c to easily service
 217          * requests from the other device when we postpone our active request.
 218          */
 219
 220         /* Data buffer size chosen based on the tape's recommendation */
 221         int buffer_size;
 222         /* merge buffer */
 223         struct idetape_bh *merge_bh;
 224         /* size of the merge buffer */
 225         int merge_bh_size;
 226         /* pointer to current buffer head within the merge buffer */
 227         struct idetape_bh *bh;
 228         char *b_data;
 229         int b_count;
 230
 231         int pages_per_buffer;
 232         /* Wasted space in each stage */
 233         int excess_bh_size;
 234
 235         /* Measures average tape speed */
 236         unsigned long avg_time;
 237         int avg_size;
 238         int avg_speed;
 239
 240         /* the door is currently locked */
 241         int door_locked;
 242         /* the tape hardware is write protected */
 243         char drv_write_prot;
 244         /* the tape is write protected (hardware or opened as read-only) */
 245         char write_prot;
 246
 247         u32 debug_mask;
 248 } idetape_tape_t;
 249
 250 static DEFINE_MUTEX(idetape_ref_mutex);
 251
 252 static struct class *idetape_sysfs_class;
 253
 254 static void ide_tape_release(struct device *);
 255
 256 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
 257 {
 258         struct ide_tape_obj *tape = NULL;
 259
 260         mutex_lock(&idetape_ref_mutex);
 261         tape = ide_drv_g(disk, ide_tape_obj);
 262         if (tape) {
 263                 if (ide_device_get(tape->drive))
 264                         tape = NULL;
 265                 else
 266                         get_device(&tape->dev);
 267         }
 268         mutex_unlock(&idetape_ref_mutex);
 269         return tape;
 270 }
 271
 272 static void ide_tape_put(struct ide_tape_obj *tape)
 273 {
 274         ide_drive_t *drive = tape->drive;
 275
 276         mutex_lock(&idetape_ref_mutex);
 277         put_device(&tape->dev);
 278         ide_device_put(drive);
 279         mutex_unlock(&idetape_ref_mutex);
 280 }
 281
 282 /*
 283  * The variables below are used for the character device interface. Additional
 284  * state variables are defined in our ide_drive_t structure.
 285  */
 286 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
 287
 288 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
 289 {
 290         struct ide_tape_obj *tape = NULL;
 291
 292         mutex_lock(&idetape_ref_mutex);
 293         tape = idetape_devs[i];
 294         if (tape)
 295                 get_device(&tape->dev);
 296         mutex_unlock(&idetape_ref_mutex);
 297         return tape;
 298 }
 299
 300 static int idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 301                                   unsigned int bcount)
 302 {
 303         struct idetape_bh *bh = pc->bh;
 304         int count;
 305
 306         while (bcount) {
 307                 if (bh == NULL)
 308                         break;
 309                 count = min(
 310                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
 311                         bcount);
 312                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
 313                                         atomic_read(&bh->b_count), count);
 314                 bcount -= count;
 315                 atomic_add(count, &bh->b_count);
 316                 if (atomic_read(&bh->b_count) == bh->b_size) {
 317                         bh = bh->b_reqnext;
 318                         if (bh)
 319                                 atomic_set(&bh->b_count, 0);
 320                 }
 321         }
 322
 323         pc->bh = bh;
 324
 325         return bcount;
 326 }
 327
 328 static int idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 329                                    unsigned int bcount)
 330 {
 331         struct idetape_bh *bh = pc->bh;
 332         int count;
 333
 334         while (bcount) {
 335                 if (bh == NULL)
 336                         break;
 337                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
 338                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
 339                 bcount -= count;
 340                 pc->b_data += count;
 341                 pc->b_count -= count;
 342                 if (!pc->b_count) {
 343                         bh = bh->b_reqnext;
 344                         pc->bh = bh;
 345                         if (bh) {
 346                                 pc->b_data = bh->b_data;
 347                                 pc->b_count = atomic_read(&bh->b_count);
 348                         }
 349                 }
 350         }
 351
 352         return bcount;
 353 }
 354
 355 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
 356 {
 357         struct idetape_bh *bh = pc->bh;
 358         int count;
 359         unsigned int bcount = pc->xferred;
 360
 361         if (pc->flags & PC_FLAG_WRITING)
 362                 return;
 363         while (bcount) {
 364                 if (bh == NULL) {
 365                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 366                                         __func__);
 367                         return;
 368                 }
 369                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
 370                 atomic_set(&bh->b_count, count);
 371                 if (atomic_read(&bh->b_count) == bh->b_size)
 372                         bh = bh->b_reqnext;
 373                 bcount -= count;
 374         }
 375         pc->bh = bh;
 376 }
 377
 378 /*
 379  * called on each failed packet command retry to analyze the request sense. We
 380  * currently do not utilize this information.
 381  */
 382 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 383 {
 384         idetape_tape_t *tape = drive->driver_data;
 385         struct ide_atapi_pc *pc = drive->failed_pc;
 386
 387         tape->sense_key = sense[2] & 0xF;
 388         tape->asc       = sense[12];
 389         tape->ascq      = sense[13];
 390
 391         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 392                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 393
 394         /* Correct pc->xferred by asking the tape.       */
 395         if (pc->flags & PC_FLAG_DMA_ERROR) {
 396                 pc->xferred = pc->req_xfer -
 397                         tape->blk_size *
 398                         get_unaligned_be32(&sense[3]);
 399                 idetape_update_buffers(drive, pc);
 400         }
 401
 402         /*
 403          * If error was the result of a zero-length read or write command,
 404          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
 405          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
 406          */
 407         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
 408             /* length == 0 */
 409             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
 410                 if (tape->sense_key == 5) {
 411                         /* don't report an error, everything's ok */
 412                         pc->error = 0;
 413                         /* don't retry read/write */
 414                         pc->flags |= PC_FLAG_ABORT;
 415                 }
 416         }
 417         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
 418                 pc->error = IDE_DRV_ERROR_FILEMARK;
 419                 pc->flags |= PC_FLAG_ABORT;
 420         }
 421         if (pc->c[0] == WRITE_6) {
 422                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
 423                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
 424                         pc->error = IDE_DRV_ERROR_EOD;
 425                         pc->flags |= PC_FLAG_ABORT;
 426                 }
 427         }
 428         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 429                 if (tape->sense_key == 8) {
 430                         pc->error = IDE_DRV_ERROR_EOD;
 431                         pc->flags |= PC_FLAG_ABORT;
 432                 }
 433                 if (!(pc->flags & PC_FLAG_ABORT) &&
 434                     pc->xferred)
 435                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 436         }
 437 }
 438
 439 /* Free data buffers completely. */
 440 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
 441 {
 442         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
 443
 444         while (bh) {
 445                 u32 size = bh->b_size;
 446
 447                 while (size) {
 448                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
 449
 450                         if (bh->b_data)
 451                                 free_pages((unsigned long)bh->b_data, order);
 452
 453                         size &= (order-1);
 454                         bh->b_data += (1 << order) * PAGE_SIZE;
 455                 }
 456                 prev_bh = bh;
 457                 bh = bh->b_reqnext;
 458                 kfree(prev_bh);
 459         }
 460 }
 461
 462 static void ide_tape_handle_dsc(ide_drive_t *);
 463
 464 static int ide_tape_callback(ide_drive_t *drive, int dsc)
 465 {
 466         idetape_tape_t *tape = drive->driver_data;
 467         struct ide_atapi_pc *pc = drive->pc;
 468         struct request *rq = drive->hwif->rq;
 469         int uptodate = pc->error ? 0 : 1;
 470         int err = uptodate ? 0 : IDE_DRV_ERROR_GENERAL;
 471
 472         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 473
 474         if (dsc)
 475                 ide_tape_handle_dsc(drive);
 476
 477         if (drive->failed_pc == pc)
 478                 drive->failed_pc = NULL;
 479
 480         if (pc->c[0] == REQUEST_SENSE) {
 481                 if (uptodate)
 482                         idetape_analyze_error(drive, pc->buf);
 483                 else
 484                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
 485                                         "itself - Aborting request!\n");
 486         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 487                 int blocks = pc->xferred / tape->blk_size;
 488
 489                 tape->avg_size += blocks * tape->blk_size;
 490
 491                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
 492                         tape->avg_speed = tape->avg_size * HZ /
 493                                 (jiffies - tape->avg_time) / 1024;
 494                         tape->avg_size = 0;
 495                         tape->avg_time = jiffies;
 496                 }
 497
 498                 tape->first_frame += blocks;
 499                 rq->current_nr_sectors -= blocks;
 500
 501                 if (pc->error) {
 502                         uptodate = 0;
 503                         err = pc->error;
 504                 }
 505         } else if (pc->c[0] == READ_POSITION && uptodate) {
 506                 u8 *readpos = pc->buf;
 507
 508                 debug_log(DBG_SENSE, "BOP - %s\n",
 509                                 (readpos[0] & 0x80) ? "Yes" : "No");
 510                 debug_log(DBG_SENSE, "EOP - %s\n",
 511                                 (readpos[0] & 0x40) ? "Yes" : "No");
 512
 513                 if (readpos[0] & 0x4) {
 514                         printk(KERN_INFO "ide-tape: Block location is unknown"
 515                                          "to the tape\n");
 516                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
 517                         uptodate = 0;
 518                         err = IDE_DRV_ERROR_GENERAL;
 519                 } else {
 520                         debug_log(DBG_SENSE, "Block Location - %u\n",
 521                                         be32_to_cpup((__be32 *)&readpos[4]));
 522
 523                         tape->partition = readpos[1];
 524                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
 525                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
 526                 }
 527         }
 528
 529         rq->errors = err;
 530
 531         return uptodate;
 532 }
 533
 534 /*
 535  * Postpone the current request so that ide.c will be able to service requests
 536  * from another device on the same port while we are polling for DSC.
 537  */
 538 static void idetape_postpone_request(ide_drive_t *drive)
 539 {
 540         idetape_tape_t *tape = drive->driver_data;
 541
 542         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 543
 544         tape->postponed_rq = drive->hwif->rq;
 545
 546         ide_stall_queue(drive, tape->dsc_poll_freq);
 547 }
 548
 549 static void ide_tape_handle_dsc(ide_drive_t *drive)
 550 {
 551         idetape_tape_t *tape = drive->driver_data;
 552
 553         /* Media access command */
 554         tape->dsc_polling_start = jiffies;
 555         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
 556         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
 557         /* Allow ide.c to handle other requests */
 558         idetape_postpone_request(drive);
 559 }
 560
 561 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 562                                 unsigned int bcount, int write)
 563 {
 564         unsigned int bleft;
 565
 566         if (write)
 567                 bleft = idetape_output_buffers(drive, pc, bcount);
 568         else
 569                 bleft = idetape_input_buffers(drive, pc, bcount);
 570
 571         return bcount - bleft;
 572 }
 573
 574 /*
 575  * Packet Command Interface
 576  *
 577  * The current Packet Command is available in drive->pc, and will not change
 578  * until we finish handling it. Each packet command is associated with a
 579  * callback function that will be called when the command is finished.
 580  *
 581  * The handling will be done in three stages:
 582  *
 583  * 1. ide_tape_issue_pc will send the packet command to the drive, and will set
 584  * the interrupt handler to ide_pc_intr.
 585  *
 586  * 2. On each interrupt, ide_pc_intr will be called. This step will be
 587  * repeated until the device signals us that no more interrupts will be issued.
 588  *
 589  * 3. ATAPI Tape media access commands have immediate status with a delayed
 590  * process. In case of a successful initiation of a media access packet command,
 591  * the DSC bit will be set when the actual execution of the command is finished.
 592  * Since the tape drive will not issue an interrupt, we have to poll for this
 593  * event. In this case, we define the request as "low priority request" by
 594  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
 595  * exit the driver.
 596  *
 597  * ide.c will then give higher priority to requests which originate from the
 598  * other device, until will change rq_status to RQ_ACTIVE.
 599  *
 600  * 4. When the packet command is finished, it will be checked for errors.
 601  *
 602  * 5. In case an error was found, we queue a request sense packet command in
 603  * front of the request queue and retry the operation up to
 604  * IDETAPE_MAX_PC_RETRIES times.
 605  *
 606  * 6. In case no error was found, or we decided to give up and not to retry
 607  * again, the callback function will be called and then we will handle the next
 608  * request.
 609  */
 610
 611 static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
 612                                          struct ide_cmd *cmd,
 613                                          struct ide_atapi_pc *pc)
 614 {
 615         idetape_tape_t *tape = drive->driver_data;
 616
 617         if (drive->pc->c[0] == REQUEST_SENSE &&
 618             pc->c[0] == REQUEST_SENSE) {
 619                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
 620                         "Two request sense in serial were issued\n");
 621         }
 622
 623         if (drive->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
 624                 drive->failed_pc = pc;
 625
 626         /* Set the current packet command */
 627         drive->pc = pc;
 628
 629         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
 630                 (pc->flags & PC_FLAG_ABORT)) {
 631                 /*
 632                  * We will "abort" retrying a packet command in case legitimate
 633                  * error code was received (crossing a filemark, or end of the
 634                  * media, for example).
 635                  */
 636                 if (!(pc->flags & PC_FLAG_ABORT)) {
 637                         if (!(pc->c[0] == TEST_UNIT_READY &&
 638                               tape->sense_key == 2 && tape->asc == 4 &&
 639                              (tape->ascq == 1 || tape->ascq == 8))) {
 640                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
 641                                                 "pc = %2x, key = %2x, "
 642                                                 "asc = %2x, ascq = %2x\n",
 643                                                 tape->name, pc->c[0],
 644                                                 tape->sense_key, tape->asc,
 645                                                 tape->ascq);
 646                         }
 647                         /* Giving up */
 648                         pc->error = IDE_DRV_ERROR_GENERAL;
 649                 }
 650                 drive->failed_pc = NULL;
 651                 drive->pc_callback(drive, 0);
 652                 return ide_stopped;
 653         }
 654         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
 655
 656         pc->retries++;
 657
 658         return ide_issue_pc(drive, cmd);
 659 }
 660
 661 /* A mode sense command is used to "sense" tape parameters. */
 662 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
 663 {
 664         ide_init_pc(pc);
 665         pc->c[0] = MODE_SENSE;
 666         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
 667                 /* DBD = 1 - Don't return block descriptors */
 668                 pc->c[1] = 8;
 669         pc->c[2] = page_code;
 670         /*
 671          * Changed pc->c[3] to 0 (255 will at best return unused info).
 672          *
 673          * For SCSI this byte is defined as subpage instead of high byte
 674          * of length and some IDE drives seem to interpret it this way
 675          * and return an error when 255 is used.
 676          */
 677         pc->c[3] = 0;
 678         /* We will just discard data in that case */
 679         pc->c[4] = 255;
 680         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
 681                 pc->req_xfer = 12;
 682         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
 683                 pc->req_xfer = 24;
 684         else
 685                 pc->req_xfer = 50;
 686 }
 687
 688 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
 689 {
 690         ide_hwif_t *hwif = drive->hwif;
 691         idetape_tape_t *tape = drive->driver_data;
 692         struct ide_atapi_pc *pc = drive->pc;
 693         u8 stat;
 694
 695         stat = hwif->tp_ops->read_status(hwif);
 696
 697         if (stat & ATA_DSC) {
 698                 if (stat & ATA_ERR) {
 699                         /* Error detected */
 700                         if (pc->c[0] != TEST_UNIT_READY)
 701                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
 702                                                 tape->name);
 703                         /* Retry operation */
 704                         ide_retry_pc(drive, tape->disk);
 705                         return ide_stopped;
 706                 }
 707                 pc->error = 0;
 708         } else {
 709                 pc->error = IDE_DRV_ERROR_GENERAL;
 710                 drive->failed_pc = NULL;
 711         }
 712         drive->pc_callback(drive, 0);
 713         return ide_stopped;
 714 }
 715
 716 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
 717                                    struct ide_atapi_pc *pc, struct request *rq,
 718                                    u8 opcode)
 719 {
 720         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
 721         unsigned int length = rq->current_nr_sectors;
 722
 723         ide_init_pc(pc);
 724         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
 725         pc->c[1] = 1;
 726         pc->bh = bh;
 727         pc->buf = NULL;
 728         pc->buf_size = length * tape->blk_size;
 729         pc->req_xfer = pc->buf_size;
 730         if (pc->req_xfer == tape->buffer_size)
 731                 pc->flags |= PC_FLAG_DMA_OK;
 732
 733         if (opcode == READ_6) {
 734                 pc->c[0] = READ_6;
 735                 atomic_set(&bh->b_count, 0);
 736         } else if (opcode == WRITE_6) {
 737                 pc->c[0] = WRITE_6;
 738                 pc->flags |= PC_FLAG_WRITING;
 739                 pc->b_data = bh->b_data;
 740                 pc->b_count = atomic_read(&bh->b_count);
 741         }
 742
 743         memcpy(rq->cmd, pc->c, 12);
 744 }
 745
 746 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 747                                           struct request *rq, sector_t block)
 748 {
 749         ide_hwif_t *hwif = drive->hwif;
 750         idetape_tape_t *tape = drive->driver_data;
 751         struct ide_atapi_pc *pc = NULL;
 752         struct request *postponed_rq = tape->postponed_rq;
 753         struct ide_cmd cmd;
 754         u8 stat;
 755
 756         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
 757                         " current_nr_sectors: %u\n",
 758                         (unsigned long long)rq->sector, rq->nr_sectors,
 759                         rq->current_nr_sectors);
 760
 761         if (!blk_special_request(rq)) {
 762                 /* We do not support buffer cache originated requests. */
 763                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
 764                         "request queue (%d)\n", drive->name, rq->cmd_type);
 765                 if (blk_fs_request(rq) == 0 && rq->errors == 0)
 766                         rq->errors = -EIO;
 767                 ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
 768                 return ide_stopped;
 769         }
 770
 771         /* Retry a failed packet command */
 772         if (drive->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
 773                 pc = drive->failed_pc;
 774                 goto out;
 775         }
 776
 777         if (postponed_rq != NULL)
 778                 if (rq != postponed_rq) {
 779                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
 780                                         "Two DSC requests were queued\n");
 781                         drive->failed_pc = NULL;
 782                         rq->errors = 0;
 783                         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 784                         return ide_stopped;
 785                 }
 786
 787         tape->postponed_rq = NULL;
 788
 789         /*
 790          * If the tape is still busy, postpone our request and service
 791          * the other device meanwhile.
 792          */
 793         stat = hwif->tp_ops->read_status(hwif);
 794
 795         if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
 796             (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
 797                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 798
 799         if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
 800                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 801                 drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
 802         }
 803
 804         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
 805             (stat & ATA_DSC) == 0) {
 806                 if (postponed_rq == NULL) {
 807                         tape->dsc_polling_start = jiffies;
 808                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
 809                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
 810                 } else if (time_after(jiffies, tape->dsc_timeout)) {
 811                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
 812                                 tape->name);
 813                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 814                                 idetape_media_access_finished(drive);
 815                                 return ide_stopped;
 816                         } else {
 817                                 return ide_do_reset(drive);
 818                         }
 819                 } else if (time_after(jiffies,
 820                                         tape->dsc_polling_start +
 821                                         IDETAPE_DSC_MA_THRESHOLD))
 822                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
 823                 idetape_postpone_request(drive);
 824                 return ide_stopped;
 825         }
 826         if (rq->cmd[13] & REQ_IDETAPE_READ) {
 827                 pc = &tape->queued_pc;
 828                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
 829                 goto out;
 830         }
 831         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
 832                 pc = &tape->queued_pc;
 833                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
 834                 goto out;
 835         }
 836         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
 837                 pc = (struct ide_atapi_pc *) rq->buffer;
 838                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
 839                 rq->cmd[13] |= REQ_IDETAPE_PC2;
 840                 goto out;
 841         }
 842         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 843                 idetape_media_access_finished(drive);
 844                 return ide_stopped;
 845         }
 846         BUG();
 847
 848 out:
 849         memset(&cmd, 0, sizeof(cmd));
 850
 851         if (rq_data_dir(rq))
 852                 cmd.tf_flags |= IDE_TFLAG_WRITE;
 853
 854         cmd.rq = rq;
 855
 856         return ide_tape_issue_pc(drive, &cmd, pc);
 857 }
 858
 859 /*
 860  * The function below uses __get_free_pages to allocate a data buffer of size
 861  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
 862  * much as possible.
 863  *
 864  * It returns a pointer to the newly allocated buffer, or NULL in case of
 865  * failure.
 866  */
 867 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
 868                                                   int full, int clear)
 869 {
 870         struct idetape_bh *prev_bh, *bh, *merge_bh;
 871         int pages = tape->pages_per_buffer;
 872         unsigned int order, b_allocd;
 873         char *b_data = NULL;
 874
 875         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
 876         bh = merge_bh;
 877         if (bh == NULL)
 878                 goto abort;
 879
 880         order = fls(pages) - 1;
 881         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 882         if (!bh->b_data)
 883                 goto abort;
 884         b_allocd = (1 << order) * PAGE_SIZE;
 885         pages &= (order-1);
 886
 887         if (clear)
 888                 memset(bh->b_data, 0, b_allocd);
 889         bh->b_reqnext = NULL;
 890         bh->b_size = b_allocd;
 891         atomic_set(&bh->b_count, full ? bh->b_size : 0);
 892
 893         while (pages) {
 894                 order = fls(pages) - 1;
 895                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 896                 if (!b_data)
 897                         goto abort;
 898                 b_allocd = (1 << order) * PAGE_SIZE;
 899
 900                 if (clear)
 901                         memset(b_data, 0, b_allocd);
 902
 903                 /* newly allocated page frames below buffer header or ...*/
 904                 if (bh->b_data == b_data + b_allocd) {
 905                         bh->b_size += b_allocd;
 906                         bh->b_data -= b_allocd;
 907                         if (full)
 908                                 atomic_add(b_allocd, &bh->b_count);
 909                         continue;
 910                 }
 911                 /* they are above the header */
 912                 if (b_data == bh->b_data + bh->b_size) {
 913                         bh->b_size += b_allocd;
 914                         if (full)
 915                                 atomic_add(b_allocd, &bh->b_count);
 916                         continue;
 917                 }
 918                 prev_bh = bh;
 919                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
 920                 if (!bh) {
 921                         free_pages((unsigned long) b_data, order);
 922                         goto abort;
 923                 }
 924                 bh->b_reqnext = NULL;
 925                 bh->b_data = b_data;
 926                 bh->b_size = b_allocd;
 927                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
 928                 prev_bh->b_reqnext = bh;
 929
 930                 pages &= (order-1);
 931         }
 932
 933         bh->b_size -= tape->excess_bh_size;
 934         if (full)
 935                 atomic_sub(tape->excess_bh_size, &bh->b_count);
 936         return merge_bh;
 937 abort:
 938         ide_tape_kfree_buffer(tape);
 939         return NULL;
 940 }
 941
 942 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
 943                                         const char __user *buf, int n)
 944 {
 945         struct idetape_bh *bh = tape->bh;
 946         int count;
 947         int ret = 0;
 948
 949         while (n) {
 950                 if (bh == NULL) {
 951                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 952                                         __func__);
 953                         return 1;
 954                 }
 955                 count = min((unsigned int)
 956                                 (bh->b_size - atomic_read(&bh->b_count)),
 957                                 (unsigned int)n);
 958                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
 959                                 count))
 960                         ret = 1;
 961                 n -= count;
 962                 atomic_add(count, &bh->b_count);
 963                 buf += count;
 964                 if (atomic_read(&bh->b_count) == bh->b_size) {
 965                         bh = bh->b_reqnext;
 966                         if (bh)
 967                                 atomic_set(&bh->b_count, 0);
 968                 }
 969         }
 970         tape->bh = bh;
 971         return ret;
 972 }
 973
 974 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
 975                                       int n)
 976 {
 977         struct idetape_bh *bh = tape->bh;
 978         int count;
 979         int ret = 0;
 980
 981         while (n) {
 982                 if (bh == NULL) {
 983                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 984                                         __func__);
 985                         return 1;
 986                 }
 987                 count = min(tape->b_count, n);
 988                 if  (copy_to_user(buf, tape->b_data, count))
 989                         ret = 1;
 990                 n -= count;
 991                 tape->b_data += count;
 992                 tape->b_count -= count;
 993                 buf += count;
 994                 if (!tape->b_count) {
 995                         bh = bh->b_reqnext;
 996                         tape->bh = bh;
 997                         if (bh) {
 998                                 tape->b_data = bh->b_data;
 999                                 tape->b_count = atomic_read(&bh->b_count);
1000                         }
1001                 }
1002         }
1003         return ret;
1004 }
1005
1006 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1007 {
1008         struct idetape_bh *bh = tape->merge_bh;
1009         tape->bh = tape->merge_bh;
1010
1011         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1012                 atomic_set(&bh->b_count, 0);
1013         else {
1014                 tape->b_data = bh->b_data;
1015                 tape->b_count = atomic_read(&bh->b_count);
1016         }
1017 }
1018
1019 /*
1020  * Write a filemark if write_filemark=1. Flush the device buffers without
1021  * writing a filemark otherwise.
1022  */
1023 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1024                 struct ide_atapi_pc *pc, int write_filemark)
1025 {
1026         ide_init_pc(pc);
1027         pc->c[0] = WRITE_FILEMARKS;
1028         pc->c[4] = write_filemark;
1029         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1030 }
1031
1032 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1033 {
1034         idetape_tape_t *tape = drive->driver_data;
1035         struct gendisk *disk = tape->disk;
1036         int load_attempted = 0;
1037
1038         /* Wait for the tape to become ready */
1039         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1040         timeout += jiffies;
1041         while (time_before(jiffies, timeout)) {
1042                 if (ide_do_test_unit_ready(drive, disk) == 0)
1043                         return 0;
1044                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1045                     || (tape->asc == 0x3A)) {
1046                         /* no media */
1047                         if (load_attempted)
1048                                 return -ENOMEDIUM;
1049                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1050                         load_attempted = 1;
1051                 /* not about to be ready */
1052                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1053                              (tape->ascq == 1 || tape->ascq == 8)))
1054                         return -EIO;
1055                 msleep(100);
1056         }
1057         return -EIO;
1058 }
1059
1060 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1061 {
1062         struct ide_tape_obj *tape = drive->driver_data;
1063         struct ide_atapi_pc pc;
1064         int rc;
1065
1066         idetape_create_write_filemark_cmd(drive, &pc, 0);
1067         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1068         if (rc)
1069                 return rc;
1070         idetape_wait_ready(drive, 60 * 5 * HZ);
1071         return 0;
1072 }
1073
1074 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1075 {
1076         ide_init_pc(pc);
1077         pc->c[0] = READ_POSITION;
1078         pc->req_xfer = 20;
1079 }
1080
1081 static int idetape_read_position(ide_drive_t *drive)
1082 {
1083         idetape_tape_t *tape = drive->driver_data;
1084         struct ide_atapi_pc pc;
1085         int position;
1086
1087         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1088
1089         idetape_create_read_position_cmd(&pc);
1090         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1091                 return -1;
1092         position = tape->first_frame;
1093         return position;
1094 }
1095
1096 static void idetape_create_locate_cmd(ide_drive_t *drive,
1097                 struct ide_atapi_pc *pc,
1098                 unsigned int block, u8 partition, int skip)
1099 {
1100         ide_init_pc(pc);
1101         pc->c[0] = POSITION_TO_ELEMENT;
1102         pc->c[1] = 2;
1103         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1104         pc->c[8] = partition;
1105         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1106 }
1107
1108 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1109 {
1110         idetape_tape_t *tape = drive->driver_data;
1111
1112         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1113                 return;
1114
1115         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1116         tape->merge_bh_size = 0;
1117         if (tape->merge_bh != NULL) {
1118                 ide_tape_kfree_buffer(tape);
1119                 tape->merge_bh = NULL;
1120         }
1121
1122         tape->chrdev_dir = IDETAPE_DIR_NONE;
1123 }
1124
1125 /*
1126  * Position the tape to the requested block using the LOCATE packet command.
1127  * A READ POSITION command is then issued to check where we are positioned. Like
1128  * all higher level operations, we queue the commands at the tail of the request
1129  * queue and wait for their completion.
1130  */
1131 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1132                 u8 partition, int skip)
1133 {
1134         idetape_tape_t *tape = drive->driver_data;
1135         struct gendisk *disk = tape->disk;
1136         int retval;
1137         struct ide_atapi_pc pc;
1138
1139         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1140                 __ide_tape_discard_merge_buffer(drive);
1141         idetape_wait_ready(drive, 60 * 5 * HZ);
1142         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1143         retval = ide_queue_pc_tail(drive, disk, &pc);
1144         if (retval)
1145                 return (retval);
1146
1147         idetape_create_read_position_cmd(&pc);
1148         return ide_queue_pc_tail(drive, disk, &pc);
1149 }
1150
1151 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1152                                           int restore_position)
1153 {
1154         idetape_tape_t *tape = drive->driver_data;
1155         int seek, position;
1156
1157         __ide_tape_discard_merge_buffer(drive);
1158         if (restore_position) {
1159                 position = idetape_read_position(drive);
1160                 seek = position > 0 ? position : 0;
1161                 if (idetape_position_tape(drive, seek, 0, 0)) {
1162                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1163                                          " %s\n", tape->name, __func__);
1164                         return;
1165                 }
1166         }
1167 }
1168
1169 /*
1170  * Generate a read/write request for the block device interface and wait for it
1171  * to be serviced.
1172  */
1173 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1174                                  struct idetape_bh *bh)
1175 {
1176         idetape_tape_t *tape = drive->driver_data;
1177         struct request *rq;
1178         int ret, errors;
1179
1180         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1181
1182         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1183         rq->cmd_type = REQ_TYPE_SPECIAL;
1184         rq->cmd[13] = cmd;
1185         rq->rq_disk = tape->disk;
1186         rq->special = (void *)bh;
1187         rq->sector = tape->first_frame;
1188         rq->nr_sectors = blocks;
1189         rq->current_nr_sectors = blocks;
1190         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1191
1192         errors = rq->errors;
1193         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1194         blk_put_request(rq);
1195
1196         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1197                 return 0;
1198
1199         if (tape->merge_bh)
1200                 idetape_init_merge_buffer(tape);
1201         if (errors == IDE_DRV_ERROR_GENERAL)
1202                 return -EIO;
1203         return ret;
1204 }
1205
1206 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1207 {
1208         ide_init_pc(pc);
1209         pc->c[0] = INQUIRY;
1210         pc->c[4] = 254;
1211         pc->req_xfer = 254;
1212 }
1213
1214 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1215                 struct ide_atapi_pc *pc)
1216 {
1217         ide_init_pc(pc);
1218         pc->c[0] = REZERO_UNIT;
1219         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1220 }
1221
1222 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1223 {
1224         ide_init_pc(pc);
1225         pc->c[0] = ERASE;
1226         pc->c[1] = 1;
1227         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1228 }
1229
1230 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1231 {
1232         ide_init_pc(pc);
1233         pc->c[0] = SPACE;
1234         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1235         pc->c[1] = cmd;
1236         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1237 }
1238
1239 /* Queue up a character device originated write request. */
1240 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1241 {
1242         idetape_tape_t *tape = drive->driver_data;
1243
1244         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1245
1246         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1247                                      blocks, tape->merge_bh);
1248 }
1249
1250 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1251 {
1252         idetape_tape_t *tape = drive->driver_data;
1253         int blocks, min;
1254         struct idetape_bh *bh;
1255
1256         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1257                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1258                                 " but we are not writing.\n");
1259                 return;
1260         }
1261         if (tape->merge_bh_size > tape->buffer_size) {
1262                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1263                 tape->merge_bh_size = tape->buffer_size;
1264         }
1265         if (tape->merge_bh_size) {
1266                 blocks = tape->merge_bh_size / tape->blk_size;
1267                 if (tape->merge_bh_size % tape->blk_size) {
1268                         unsigned int i;
1269
1270                         blocks++;
1271                         i = tape->blk_size - tape->merge_bh_size %
1272                                 tape->blk_size;
1273                         bh = tape->bh->b_reqnext;
1274                         while (bh) {
1275                                 atomic_set(&bh->b_count, 0);
1276                                 bh = bh->b_reqnext;
1277                         }
1278                         bh = tape->bh;
1279                         while (i) {
1280                                 if (bh == NULL) {
1281                                         printk(KERN_INFO "ide-tape: bug,"
1282                                                          " bh NULL\n");
1283                                         break;
1284                                 }
1285                                 min = min(i, (unsigned int)(bh->b_size -
1286                                                 atomic_read(&bh->b_count)));
1287                                 memset(bh->b_data + atomic_read(&bh->b_count),
1288                                                 0, min);
1289                                 atomic_add(min, &bh->b_count);
1290                                 i -= min;
1291                                 bh = bh->b_reqnext;
1292                         }
1293                 }
1294                 (void) idetape_add_chrdev_write_request(drive, blocks);
1295                 tape->merge_bh_size = 0;
1296         }
1297         if (tape->merge_bh != NULL) {
1298                 ide_tape_kfree_buffer(tape);
1299                 tape->merge_bh = NULL;
1300         }
1301         tape->chrdev_dir = IDETAPE_DIR_NONE;
1302 }
1303
1304 static int idetape_init_read(ide_drive_t *drive)
1305 {
1306         idetape_tape_t *tape = drive->driver_data;
1307         int bytes_read;
1308
1309         /* Initialize read operation */
1310         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1311                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1312                         ide_tape_flush_merge_buffer(drive);
1313                         idetape_flush_tape_buffers(drive);
1314                 }
1315                 if (tape->merge_bh || tape->merge_bh_size) {
1316                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1317                                          " 0 now\n");
1318                         tape->merge_bh_size = 0;
1319                 }
1320                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1321                 if (!tape->merge_bh)
1322                         return -ENOMEM;
1323                 tape->chrdev_dir = IDETAPE_DIR_READ;
1324
1325                 /*
1326                  * Issue a read 0 command to ensure that DSC handshake is
1327                  * switched from completion mode to buffer available mode.
1328                  * No point in issuing this if DSC overlap isn't supported, some
1329                  * drives (Seagate STT3401A) will return an error.
1330                  */
1331                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1332                         bytes_read = idetape_queue_rw_tail(drive,
1333                                                         REQ_IDETAPE_READ, 0,
1334                                                         tape->merge_bh);
1335                         if (bytes_read < 0) {
1336                                 ide_tape_kfree_buffer(tape);
1337                                 tape->merge_bh = NULL;
1338                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1339                                 return bytes_read;
1340                         }
1341                 }
1342         }
1343
1344         return 0;
1345 }
1346
1347 /* called from idetape_chrdev_read() to service a chrdev read request. */
1348 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1349 {
1350         idetape_tape_t *tape = drive->driver_data;
1351
1352         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1353
1354         /* If we are at a filemark, return a read length of 0 */
1355         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1356                 return 0;
1357
1358         idetape_init_read(drive);
1359
1360         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1361                                      tape->merge_bh);
1362 }
1363
1364 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1365 {
1366         idetape_tape_t *tape = drive->driver_data;
1367         struct idetape_bh *bh;
1368         int blocks;
1369
1370         while (bcount) {
1371                 unsigned int count;
1372
1373                 bh = tape->merge_bh;
1374                 count = min(tape->buffer_size, bcount);
1375                 bcount -= count;
1376                 blocks = count / tape->blk_size;
1377                 while (count) {
1378                         atomic_set(&bh->b_count,
1379                                    min(count, (unsigned int)bh->b_size));
1380                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1381                         count -= atomic_read(&bh->b_count);
1382                         bh = bh->b_reqnext;
1383                 }
1384                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1385                                       tape->merge_bh);
1386         }
1387 }
1388
1389 /*
1390  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1391  * currently support only one partition.
1392  */
1393 static int idetape_rewind_tape(ide_drive_t *drive)
1394 {
1395         struct ide_tape_obj *tape = drive->driver_data;
1396         struct gendisk *disk = tape->disk;
1397         int retval;
1398         struct ide_atapi_pc pc;
1399
1400         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1401
1402         idetape_create_rewind_cmd(drive, &pc);
1403         retval = ide_queue_pc_tail(drive, disk, &pc);
1404         if (retval)
1405                 return retval;
1406
1407         idetape_create_read_position_cmd(&pc);
1408         retval = ide_queue_pc_tail(drive, disk, &pc);
1409         if (retval)
1410                 return retval;
1411         return 0;
1412 }
1413
1414 /* mtio.h compatible commands should be issued to the chrdev interface. */
1415 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1416                                 unsigned long arg)
1417 {
1418         idetape_tape_t *tape = drive->driver_data;
1419         void __user *argp = (void __user *)arg;
1420
1421         struct idetape_config {
1422                 int dsc_rw_frequency;
1423                 int dsc_media_access_frequency;
1424                 int nr_stages;
1425         } config;
1426
1427         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1428
1429         switch (cmd) {
1430         case 0x0340:
1431                 if (copy_from_user(&config, argp, sizeof(config)))
1432                         return -EFAULT;
1433                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1434                 break;
1435         case 0x0350:
1436                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1437                 config.nr_stages = 1;
1438                 if (copy_to_user(argp, &config, sizeof(config)))
1439                         return -EFAULT;
1440                 break;
1441         default:
1442                 return -EIO;
1443         }
1444         return 0;
1445 }
1446
1447 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1448                                         int mt_count)
1449 {
1450         idetape_tape_t *tape = drive->driver_data;
1451         struct gendisk *disk = tape->disk;
1452         struct ide_atapi_pc pc;
1453         int retval, count = 0;
1454         int sprev = !!(tape->caps[4] & 0x20);
1455
1456         if (mt_count == 0)
1457                 return 0;
1458         if (MTBSF == mt_op || MTBSFM == mt_op) {
1459                 if (!sprev)
1460                         return -EIO;
1461                 mt_count = -mt_count;
1462         }
1463
1464         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1465                 tape->merge_bh_size = 0;
1466                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1467                         ++count;
1468                 ide_tape_discard_merge_buffer(drive, 0);
1469         }
1470
1471         switch (mt_op) {
1472         case MTFSF:
1473         case MTBSF:
1474                 idetape_create_space_cmd(&pc, mt_count - count,
1475                                          IDETAPE_SPACE_OVER_FILEMARK);
1476                 return ide_queue_pc_tail(drive, disk, &pc);
1477         case MTFSFM:
1478         case MTBSFM:
1479                 if (!sprev)
1480                         return -EIO;
1481                 retval = idetape_space_over_filemarks(drive, MTFSF,
1482                                                       mt_count - count);
1483                 if (retval)
1484                         return retval;
1485                 count = (MTBSFM == mt_op ? 1 : -1);
1486                 return idetape_space_over_filemarks(drive, MTFSF, count);
1487         default:
1488                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1489                                 mt_op);
1490                 return -EIO;
1491         }
1492 }
1493
1494 /*
1495  * Our character device read / write functions.
1496  *
1497  * The tape is optimized to maximize throughput when it is transferring an
1498  * integral number of the "continuous transfer limit", which is a parameter of
1499  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1500  *
1501  * As of version 1.3 of the driver, the character device provides an abstract
1502  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1503  * same backup/restore procedure is supported. The driver will internally
1504  * convert the requests to the recommended transfer unit, so that an unmatch
1505  * between the user's block size to the recommended size will only result in a
1506  * (slightly) increased driver overhead, but will no longer hit performance.
1507  * This is not applicable to Onstream.
1508  */
1509 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1510                                    size_t count, loff_t *ppos)
1511 {
1512         struct ide_tape_obj *tape = file->private_data;
1513         ide_drive_t *drive = tape->drive;
1514         ssize_t bytes_read, temp, actually_read = 0, rc;
1515         ssize_t ret = 0;
1516         u16 ctl = *(u16 *)&tape->caps[12];
1517
1518         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1519
1520         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1521                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1522                         if (count > tape->blk_size &&
1523                             (count % tape->blk_size) == 0)
1524                                 tape->user_bs_factor = count / tape->blk_size;
1525         }
1526         rc = idetape_init_read(drive);
1527         if (rc < 0)
1528                 return rc;
1529         if (count == 0)
1530                 return (0);
1531         if (tape->merge_bh_size) {
1532                 actually_read = min((unsigned int)(tape->merge_bh_size),
1533                                     (unsigned int)count);
1534                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1535                         ret = -EFAULT;
1536                 buf += actually_read;
1537                 tape->merge_bh_size -= actually_read;
1538                 count -= actually_read;
1539         }
1540         while (count >= tape->buffer_size) {
1541                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1542                 if (bytes_read <= 0)
1543                         goto finish;
1544                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1545                         ret = -EFAULT;
1546                 buf += bytes_read;
1547                 count -= bytes_read;
1548                 actually_read += bytes_read;
1549         }
1550         if (count) {
1551                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1552                 if (bytes_read <= 0)
1553                         goto finish;
1554                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1555                 if (idetape_copy_stage_to_user(tape, buf, temp))
1556                         ret = -EFAULT;
1557                 actually_read += temp;
1558                 tape->merge_bh_size = bytes_read-temp;
1559         }
1560 finish:
1561         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1562                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1563
1564                 idetape_space_over_filemarks(drive, MTFSF, 1);
1565                 return 0;
1566         }
1567
1568         return ret ? ret : actually_read;
1569 }
1570
1571 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1572                                      size_t count, loff_t *ppos)
1573 {
1574         struct ide_tape_obj *tape = file->private_data;
1575         ide_drive_t *drive = tape->drive;
1576         ssize_t actually_written = 0;
1577         ssize_t ret = 0;
1578         u16 ctl = *(u16 *)&tape->caps[12];
1579
1580         /* The drive is write protected. */
1581         if (tape->write_prot)
1582                 return -EACCES;
1583
1584         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1585
1586         /* Initialize write operation */
1587         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1588                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1589                         ide_tape_discard_merge_buffer(drive, 1);
1590                 if (tape->merge_bh || tape->merge_bh_size) {
1591                         printk(KERN_ERR "ide-tape: merge_bh_size "
1592                                 "should be 0 now\n");
1593                         tape->merge_bh_size = 0;
1594                 }
1595                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1596                 if (!tape->merge_bh)
1597                         return -ENOMEM;
1598                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1599                 idetape_init_merge_buffer(tape);
1600
1601                 /*
1602                  * Issue a write 0 command to ensure that DSC handshake is
1603                  * switched from completion mode to buffer available mode. No
1604                  * point in issuing this if DSC overlap isn't supported, some
1605                  * drives (Seagate STT3401A) will return an error.
1606                  */
1607                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1608                         ssize_t retval = idetape_queue_rw_tail(drive,
1609                                                         REQ_IDETAPE_WRITE, 0,
1610                                                         tape->merge_bh);
1611                         if (retval < 0) {
1612                                 ide_tape_kfree_buffer(tape);
1613                                 tape->merge_bh = NULL;
1614                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1615                                 return retval;
1616                         }
1617                 }
1618         }
1619         if (count == 0)
1620                 return (0);
1621         if (tape->merge_bh_size) {
1622                 if (tape->merge_bh_size >= tape->buffer_size) {
1623                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1624                         tape->merge_bh_size = 0;
1625                 }
1626                 actually_written = min((unsigned int)
1627                                 (tape->buffer_size - tape->merge_bh_size),
1628                                 (unsigned int)count);
1629                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1630                                 ret = -EFAULT;
1631                 buf += actually_written;
1632                 tape->merge_bh_size += actually_written;
1633                 count -= actually_written;
1634
1635                 if (tape->merge_bh_size == tape->buffer_size) {
1636                         ssize_t retval;
1637                         tape->merge_bh_size = 0;
1638                         retval = idetape_add_chrdev_write_request(drive, ctl);
1639                         if (retval <= 0)
1640                                 return (retval);
1641                 }
1642         }
1643         while (count >= tape->buffer_size) {
1644                 ssize_t retval;
1645                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1646                         ret = -EFAULT;
1647                 buf += tape->buffer_size;
1648                 count -= tape->buffer_size;
1649                 retval = idetape_add_chrdev_write_request(drive, ctl);
1650                 actually_written += tape->buffer_size;
1651                 if (retval <= 0)
1652                         return (retval);
1653         }
1654         if (count) {
1655                 actually_written += count;
1656                 if (idetape_copy_stage_from_user(tape, buf, count))
1657                         ret = -EFAULT;
1658                 tape->merge_bh_size += count;
1659         }
1660         return ret ? ret : actually_written;
1661 }
1662
1663 static int idetape_write_filemark(ide_drive_t *drive)
1664 {
1665         struct ide_tape_obj *tape = drive->driver_data;
1666         struct ide_atapi_pc pc;
1667
1668         /* Write a filemark */
1669         idetape_create_write_filemark_cmd(drive, &pc, 1);
1670         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1671                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1672                 return -EIO;
1673         }
1674         return 0;
1675 }
1676
1677 /*
1678  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1679  * requested.
1680  *
1681  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1682  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1683  * usually not supported.
1684  *
1685  * The following commands are currently not supported:
1686  *
1687  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1688  * MT_ST_WRITE_THRESHOLD.
1689  */
1690 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1691 {
1692         idetape_tape_t *tape = drive->driver_data;
1693         struct gendisk *disk = tape->disk;
1694         struct ide_atapi_pc pc;
1695         int i, retval;
1696
1697         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1698                         mt_op, mt_count);
1699
1700         switch (mt_op) {
1701         case MTFSF:
1702         case MTFSFM:
1703         case MTBSF:
1704         case MTBSFM:
1705                 if (!mt_count)
1706                         return 0;
1707                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1708         default:
1709                 break;
1710         }
1711
1712         switch (mt_op) {
1713         case MTWEOF:
1714                 if (tape->write_prot)
1715                         return -EACCES;
1716                 ide_tape_discard_merge_buffer(drive, 1);
1717                 for (i = 0; i < mt_count; i++) {
1718                         retval = idetape_write_filemark(drive);
1719                         if (retval)
1720                                 return retval;
1721                 }
1722                 return 0;
1723         case MTREW:
1724                 ide_tape_discard_merge_buffer(drive, 0);
1725                 if (idetape_rewind_tape(drive))
1726                         return -EIO;
1727                 return 0;
1728         case MTLOAD:
1729                 ide_tape_discard_merge_buffer(drive, 0);
1730                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1731         case MTUNLOAD:
1732         case MTOFFL:
1733                 /*
1734                  * If door is locked, attempt to unlock before
1735                  * attempting to eject.
1736                  */
1737                 if (tape->door_locked) {
1738                         if (!ide_set_media_lock(drive, disk, 0))
1739                                 tape->door_locked = DOOR_UNLOCKED;
1740                 }
1741                 ide_tape_discard_merge_buffer(drive, 0);
1742                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1743                 if (!retval)
1744                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1745                 return retval;
1746         case MTNOP:
1747                 ide_tape_discard_merge_buffer(drive, 0);
1748                 return idetape_flush_tape_buffers(drive);
1749         case MTRETEN:
1750                 ide_tape_discard_merge_buffer(drive, 0);
1751                 return ide_do_start_stop(drive, disk,
1752                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1753         case MTEOM:
1754                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1755                 return ide_queue_pc_tail(drive, disk, &pc);
1756         case MTERASE:
1757                 (void)idetape_rewind_tape(drive);
1758                 idetape_create_erase_cmd(&pc);
1759                 return ide_queue_pc_tail(drive, disk, &pc);
1760         case MTSETBLK:
1761                 if (mt_count) {
1762                         if (mt_count < tape->blk_size ||
1763                             mt_count % tape->blk_size)
1764                                 return -EIO;
1765                         tape->user_bs_factor = mt_count / tape->blk_size;
1766                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1767                 } else
1768                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1769                 return 0;
1770         case MTSEEK:
1771                 ide_tape_discard_merge_buffer(drive, 0);
1772                 return idetape_position_tape(drive,
1773                         mt_count * tape->user_bs_factor, tape->partition, 0);
1774         case MTSETPART:
1775                 ide_tape_discard_merge_buffer(drive, 0);
1776                 return idetape_position_tape(drive, 0, mt_count, 0);
1777         case MTFSR:
1778         case MTBSR:
1779         case MTLOCK:
1780                 retval = ide_set_media_lock(drive, disk, 1);
1781                 if (retval)
1782                         return retval;
1783                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1784                 return 0;
1785         case MTUNLOCK:
1786                 retval = ide_set_media_lock(drive, disk, 0);
1787                 if (retval)
1788                         return retval;
1789                 tape->door_locked = DOOR_UNLOCKED;
1790                 return 0;
1791         default:
1792                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1793                                 mt_op);
1794                 return -EIO;
1795         }
1796 }
1797
1798 /*
1799  * Our character device ioctls. General mtio.h magnetic io commands are
1800  * supported here, and not in the corresponding block interface. Our own
1801  * ide-tape ioctls are supported on both interfaces.
1802  */
1803 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1804                                 unsigned int cmd, unsigned long arg)
1805 {
1806         struct ide_tape_obj *tape = file->private_data;
1807         ide_drive_t *drive = tape->drive;
1808         struct mtop mtop;
1809         struct mtget mtget;
1810         struct mtpos mtpos;
1811         int block_offset = 0, position = tape->first_frame;
1812         void __user *argp = (void __user *)arg;
1813
1814         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1815
1816         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1817                 ide_tape_flush_merge_buffer(drive);
1818                 idetape_flush_tape_buffers(drive);
1819         }
1820         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1821                 block_offset = tape->merge_bh_size /
1822                         (tape->blk_size * tape->user_bs_factor);
1823                 position = idetape_read_position(drive);
1824                 if (position < 0)
1825                         return -EIO;
1826         }
1827         switch (cmd) {
1828         case MTIOCTOP:
1829                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1830                         return -EFAULT;
1831                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1832         case MTIOCGET:
1833                 memset(&mtget, 0, sizeof(struct mtget));
1834                 mtget.mt_type = MT_ISSCSI2;
1835                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1836                 mtget.mt_dsreg =
1837                         ((tape->blk_size * tape->user_bs_factor)
1838                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1839
1840                 if (tape->drv_write_prot)
1841                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1842
1843                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1844                         return -EFAULT;
1845                 return 0;
1846         case MTIOCPOS:
1847                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1848                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1849                         return -EFAULT;
1850                 return 0;
1851         default:
1852                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1853                         ide_tape_discard_merge_buffer(drive, 1);
1854                 return idetape_blkdev_ioctl(drive, cmd, arg);
1855         }
1856 }
1857
1858 /*
1859  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1860  * block size with the reported value.
1861  */
1862 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1863 {
1864         idetape_tape_t *tape = drive->driver_data;
1865         struct ide_atapi_pc pc;
1866
1867         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1868         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1869                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1870                 if (tape->blk_size == 0) {
1871                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1872                                             "block size, assuming 32k\n");
1873                         tape->blk_size = 32768;
1874                 }
1875                 return;
1876         }
1877         tape->blk_size = (pc.buf[4 + 5] << 16) +
1878                                 (pc.buf[4 + 6] << 8)  +
1879                                  pc.buf[4 + 7];
1880         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1881 }
1882
1883 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1884 {
1885         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1886         ide_drive_t *drive;
1887         idetape_tape_t *tape;
1888         int retval;
1889
1890         if (i >= MAX_HWIFS * MAX_DRIVES)
1891                 return -ENXIO;
1892
1893         lock_kernel();
1894         tape = ide_tape_chrdev_get(i);
1895         if (!tape) {
1896                 unlock_kernel();
1897                 return -ENXIO;
1898         }
1899
1900         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1901
1902         /*
1903          * We really want to do nonseekable_open(inode, filp); here, but some
1904          * versions of tar incorrectly call lseek on tapes and bail out if that
1905          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1906          */
1907         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1908
1909         drive = tape->drive;
1910
1911         filp->private_data = tape;
1912
1913         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1914                 retval = -EBUSY;
1915                 goto out_put_tape;
1916         }
1917
1918         retval = idetape_wait_ready(drive, 60 * HZ);
1919         if (retval) {
1920                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1921                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1922                 goto out_put_tape;
1923         }
1924
1925         idetape_read_position(drive);
1926         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1927                 (void)idetape_rewind_tape(drive);
1928
1929         /* Read block size and write protect status from drive. */
1930         ide_tape_get_bsize_from_bdesc(drive);
1931
1932         /* Set write protect flag if device is opened as read-only. */
1933         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1934                 tape->write_prot = 1;
1935         else
1936                 tape->write_prot = tape->drv_write_prot;
1937
1938         /* Make sure drive isn't write protected if user wants to write. */
1939         if (tape->write_prot) {
1940                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1941                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1942                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1943                         retval = -EROFS;
1944                         goto out_put_tape;
1945                 }
1946         }
1947
1948         /* Lock the tape drive door so user can't eject. */
1949         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1950                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1951                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1952                                 tape->door_locked = DOOR_LOCKED;
1953                 }
1954         }
1955         unlock_kernel();
1956         return 0;
1957
1958 out_put_tape:
1959         ide_tape_put(tape);
1960         unlock_kernel();
1961         return retval;
1962 }
1963
1964 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1965 {
1966         idetape_tape_t *tape = drive->driver_data;
1967
1968         ide_tape_flush_merge_buffer(drive);
1969         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
1970         if (tape->merge_bh != NULL) {
1971                 idetape_pad_zeros(drive, tape->blk_size *
1972                                 (tape->user_bs_factor - 1));
1973                 ide_tape_kfree_buffer(tape);
1974                 tape->merge_bh = NULL;
1975         }
1976         idetape_write_filemark(drive);
1977         idetape_flush_tape_buffers(drive);
1978         idetape_flush_tape_buffers(drive);
1979 }
1980
1981 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
1982 {
1983         struct ide_tape_obj *tape = filp->private_data;
1984         ide_drive_t *drive = tape->drive;
1985         unsigned int minor = iminor(inode);
1986
1987         lock_kernel();
1988         tape = drive->driver_data;
1989
1990         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1991
1992         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1993                 idetape_write_release(drive, minor);
1994         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1995                 if (minor < 128)
1996                         ide_tape_discard_merge_buffer(drive, 1);
1997         }
1998
1999         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2000                 (void) idetape_rewind_tape(drive);
2001         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2002                 if (tape->door_locked == DOOR_LOCKED) {
2003                         if (!ide_set_media_lock(drive, tape->disk, 0))
2004                                 tape->door_locked = DOOR_UNLOCKED;
2005                 }
2006         }
2007         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2008         ide_tape_put(tape);
2009         unlock_kernel();
2010         return 0;
2011 }
2012
2013 static void idetape_get_inquiry_results(ide_drive_t *drive)
2014 {
2015         idetape_tape_t *tape = drive->driver_data;
2016         struct ide_atapi_pc pc;
2017         u8 pc_buf[256];
2018         char fw_rev[4], vendor_id[8], product_id[16];
2019
2020         idetape_create_inquiry_cmd(&pc);
2021         pc.buf = &pc_buf[0];
2022         pc.buf_size = sizeof(pc_buf);
2023
2024         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2025                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2026                                 tape->name);
2027                 return;
2028         }
2029         memcpy(vendor_id, &pc.buf[8], 8);
2030         memcpy(product_id, &pc.buf[16], 16);
2031         memcpy(fw_rev, &pc.buf[32], 4);
2032
2033         ide_fixstring(vendor_id, 8, 0);
2034         ide_fixstring(product_id, 16, 0);
2035         ide_fixstring(fw_rev, 4, 0);
2036
2037         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2038                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2039 }
2040
2041 /*
2042  * Ask the tape about its various parameters. In particular, we will adjust our
2043  * data transfer buffer size to the recommended value as returned by the tape.
2044  */
2045 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2046 {
2047         idetape_tape_t *tape = drive->driver_data;
2048         struct ide_atapi_pc pc;
2049         u8 *caps;
2050         u8 speed, max_speed;
2051
2052         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2053         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2054                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2055                                 " some default values\n");
2056                 tape->blk_size = 512;
2057                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2058                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2059                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2060                 return;
2061         }
2062         caps = pc.buf + 4 + pc.buf[3];
2063
2064         /* convert to host order and save for later use */
2065         speed = be16_to_cpup((__be16 *)&caps[14]);
2066         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2067
2068         *(u16 *)&caps[8] = max_speed;
2069         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2070         *(u16 *)&caps[14] = speed;
2071         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2072
2073         if (!speed) {
2074                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2075                                 "(assuming 650KB/sec)\n", drive->name);
2076                 *(u16 *)&caps[14] = 650;
2077         }
2078         if (!max_speed) {
2079                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2080                                 "(assuming 650KB/sec)\n", drive->name);
2081                 *(u16 *)&caps[8] = 650;
2082         }
2083
2084         memcpy(&tape->caps, caps, 20);
2085
2086         /* device lacks locking support according to capabilities page */
2087         if ((caps[6] & 1) == 0)
2088                 drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
2089
2090         if (caps[7] & 0x02)
2091                 tape->blk_size = 512;
2092         else if (caps[7] & 0x04)
2093                 tape->blk_size = 1024;
2094 }
2095
2096 #ifdef CONFIG_IDE_PROC_FS
2097 #define ide_tape_devset_get(name, field) \
2098 static int get_##name(ide_drive_t *drive) \
2099 { \
2100         idetape_tape_t *tape = drive->driver_data; \
2101         return tape->field; \
2102 }
2103
2104 #define ide_tape_devset_set(name, field) \
2105 static int set_##name(ide_drive_t *drive, int arg) \
2106 { \
2107         idetape_tape_t *tape = drive->driver_data; \
2108         tape->field = arg; \
2109         return 0; \
2110 }
2111
2112 #define ide_tape_devset_rw_field(_name, _field) \
2113 ide_tape_devset_get(_name, _field) \
2114 ide_tape_devset_set(_name, _field) \
2115 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2116
2117 #define ide_tape_devset_r_field(_name, _field) \
2118 ide_tape_devset_get(_name, _field) \
2119 IDE_DEVSET(_name, 0, get_##_name, NULL)
2120
2121 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2122 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2123 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2124 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2125
2126 ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
2127
2128 ide_tape_devset_rw_field(debug_mask, debug_mask);
2129 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2130
2131 ide_tape_devset_r_field(avg_speed, avg_speed);
2132 ide_tape_devset_r_field(speed, caps[14]);
2133 ide_tape_devset_r_field(buffer, caps[16]);
2134 ide_tape_devset_r_field(buffer_size, buffer_size);
2135
2136 static const struct ide_proc_devset idetape_settings[] = {
2137         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2138         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2139         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2140         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2141         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2142         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2143         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2144                                         mulf_tdsc, divf_tdsc),
2145         { NULL },
2146 };
2147 #endif
2148
2149 /*
2150  * The function below is called to:
2151  *
2152  * 1. Initialize our various state variables.
2153  * 2. Ask the tape for its capabilities.
2154  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2155  * is chosen based on the recommendation which we received in step 2.
2156  *
2157  * Note that at this point ide.c already assigned us an irq, so that we can
2158  * queue requests here and wait for their completion.
2159  */
2160 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2161 {
2162         unsigned long t;
2163         int speed;
2164         int buffer_size;
2165         u16 *ctl = (u16 *)&tape->caps[12];
2166
2167         drive->pc_callback       = ide_tape_callback;
2168         drive->pc_update_buffers = idetape_update_buffers;
2169         drive->pc_io_buffers     = ide_tape_io_buffers;
2170
2171         drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
2172
2173         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2174                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2175                                  tape->name);
2176                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2177         }
2178
2179         /* Seagate Travan drives do not support DSC overlap. */
2180         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2181                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2182
2183         tape->minor = minor;
2184         tape->name[0] = 'h';
2185         tape->name[1] = 't';
2186         tape->name[2] = '0' + minor;
2187         tape->chrdev_dir = IDETAPE_DIR_NONE;
2188
2189         idetape_get_inquiry_results(drive);
2190         idetape_get_mode_sense_results(drive);
2191         ide_tape_get_bsize_from_bdesc(drive);
2192         tape->user_bs_factor = 1;
2193         tape->buffer_size = *ctl * tape->blk_size;
2194         while (tape->buffer_size > 0xffff) {
2195                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2196                 *ctl /= 2;
2197                 tape->buffer_size = *ctl * tape->blk_size;
2198         }
2199         buffer_size = tape->buffer_size;
2200         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2201         if (buffer_size % PAGE_SIZE) {
2202                 tape->pages_per_buffer++;
2203                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2204         }
2205
2206         /* select the "best" DSC read/write polling freq */
2207         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2208
2209         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2210
2211         /*
2212          * Ensure that the number we got makes sense; limit it within
2213          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2214          */
2215         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2216                                          IDETAPE_DSC_RW_MAX);
2217         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2218                 "%lums tDSC%s\n",
2219                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2220                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2221                 tape->buffer_size / 1024,
2222                 tape->best_dsc_rw_freq * 1000 / HZ,
2223                 (drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
2224
2225         ide_proc_register_driver(drive, tape->driver);
2226 }
2227
2228 static void ide_tape_remove(ide_drive_t *drive)
2229 {
2230         idetape_tape_t *tape = drive->driver_data;
2231
2232         ide_proc_unregister_driver(drive, tape->driver);
2233         device_del(&tape->dev);
2234         ide_unregister_region(tape->disk);
2235
2236         mutex_lock(&idetape_ref_mutex);
2237         put_device(&tape->dev);
2238         mutex_unlock(&idetape_ref_mutex);
2239 }
2240
2241 static void ide_tape_release(struct device *dev)
2242 {
2243         struct ide_tape_obj *tape = to_ide_drv(dev, ide_tape_obj);
2244         ide_drive_t *drive = tape->drive;
2245         struct gendisk *g = tape->disk;
2246
2247         BUG_ON(tape->merge_bh_size);
2248
2249         drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2250         drive->driver_data = NULL;
2251         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2252         device_destroy(idetape_sysfs_class,
2253                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2254         idetape_devs[tape->minor] = NULL;
2255         g->private_data = NULL;
2256         put_disk(g);
2257         kfree(tape);
2258 }
2259
2260 #ifdef CONFIG_IDE_PROC_FS
2261 static int proc_idetape_read_name
2262         (char *page, char **start, off_t off, int count, int *eof, void *data)
2263 {
2264         ide_drive_t     *drive = (ide_drive_t *) data;
2265         idetape_tape_t  *tape = drive->driver_data;
2266         char            *out = page;
2267         int             len;
2268
2269         len = sprintf(out, "%s\n", tape->name);
2270         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2271 }
2272
2273 static ide_proc_entry_t idetape_proc[] = {
2274         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2275         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2276         { NULL, 0, NULL, NULL }
2277 };
2278
2279 static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
2280 {
2281         return idetape_proc;
2282 }
2283
2284 static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
2285 {
2286         return idetape_settings;
2287 }
2288 #endif
2289
2290 static int ide_tape_probe(ide_drive_t *);
2291
2292 static struct ide_driver idetape_driver = {
2293         .gen_driver = {
2294                 .owner          = THIS_MODULE,
2295                 .name           = "ide-tape",
2296                 .bus            = &ide_bus_type,
2297         },
2298         .probe                  = ide_tape_probe,
2299         .remove                 = ide_tape_remove,
2300         .version                = IDETAPE_VERSION,
2301         .do_request             = idetape_do_request,
2302 #ifdef CONFIG_IDE_PROC_FS
2303         .proc_entries           = ide_tape_proc_entries,
2304         .proc_devsets           = ide_tape_proc_devsets,
2305 #endif
2306 };
2307
2308 /* Our character device supporting functions, passed to register_chrdev. */
2309 static const struct file_operations idetape_fops = {
2310         .owner          = THIS_MODULE,
2311         .read           = idetape_chrdev_read,
2312         .write          = idetape_chrdev_write,
2313         .ioctl          = idetape_chrdev_ioctl,
2314         .open           = idetape_chrdev_open,
2315         .release        = idetape_chrdev_release,
2316 };
2317
2318 static int idetape_open(struct block_device *bdev, fmode_t mode)
2319 {
2320         struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk);
2321
2322         if (!tape)
2323                 return -ENXIO;
2324
2325         return 0;
2326 }
2327
2328 static int idetape_release(struct gendisk *disk, fmode_t mode)
2329 {
2330         struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
2331
2332         ide_tape_put(tape);
2333         return 0;
2334 }
2335
2336 static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
2337                         unsigned int cmd, unsigned long arg)
2338 {
2339         struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
2340         ide_drive_t *drive = tape->drive;
2341         int err = generic_ide_ioctl(drive, bdev, cmd, arg);
2342         if (err == -EINVAL)
2343                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2344         return err;
2345 }
2346
2347 static struct block_device_operations idetape_block_ops = {
2348         .owner          = THIS_MODULE,
2349         .open           = idetape_open,
2350         .release        = idetape_release,
2351         .locked_ioctl   = idetape_ioctl,
2352 };
2353
2354 static int ide_tape_probe(ide_drive_t *drive)
2355 {
2356         idetape_tape_t *tape;
2357         struct gendisk *g;
2358         int minor;
2359
2360         if (!strstr("ide-tape", drive->driver_req))
2361                 goto failed;
2362
2363         if (drive->media != ide_tape)
2364                 goto failed;
2365
2366         if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
2367             ide_check_atapi_device(drive, DRV_NAME) == 0) {
2368                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2369                                 " the driver\n", drive->name);
2370                 goto failed;
2371         }
2372         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2373         if (tape == NULL) {
2374                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2375                                 drive->name);
2376                 goto failed;
2377         }
2378
2379         g = alloc_disk(1 << PARTN_BITS);
2380         if (!g)
2381                 goto out_free_tape;
2382
2383         ide_init_disk(g, drive);
2384
2385         tape->dev.parent = &drive->gendev;
2386         tape->dev.release = ide_tape_release;
2387         dev_set_name(&tape->dev, dev_name(&drive->gendev));
2388
2389         if (device_register(&tape->dev))
2390                 goto out_free_disk;
2391
2392         tape->drive = drive;
2393         tape->driver = &idetape_driver;
2394         tape->disk = g;
2395
2396         g->private_data = &tape->driver;
2397
2398         drive->driver_data = tape;
2399
2400         mutex_lock(&idetape_ref_mutex);
2401         for (minor = 0; idetape_devs[minor]; minor++)
2402                 ;
2403         idetape_devs[minor] = tape;
2404         mutex_unlock(&idetape_ref_mutex);
2405
2406         idetape_setup(drive, tape, minor);
2407
2408         device_create(idetape_sysfs_class, &drive->gendev,
2409                       MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
2410         device_create(idetape_sysfs_class, &drive->gendev,
2411                       MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2412                       "n%s", tape->name);
2413
2414         g->fops = &idetape_block_ops;
2415         ide_register_region(g);
2416
2417         return 0;
2418
2419 out_free_disk:
2420         put_disk(g);
2421 out_free_tape:
2422         kfree(tape);
2423 failed:
2424         return -ENODEV;
2425 }
2426
2427 static void __exit idetape_exit(void)
2428 {
2429         driver_unregister(&idetape_driver.gen_driver);
2430         class_destroy(idetape_sysfs_class);
2431         unregister_chrdev(IDETAPE_MAJOR, "ht");
2432 }
2433
2434 static int __init idetape_init(void)
2435 {
2436         int error = 1;
2437         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2438         if (IS_ERR(idetape_sysfs_class)) {
2439                 idetape_sysfs_class = NULL;
2440                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2441                 error = -EBUSY;
2442                 goto out;
2443         }
2444
2445         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2446                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2447                                 " interface\n");
2448                 error = -EBUSY;
2449                 goto out_free_class;
2450         }
2451
2452         error = driver_register(&idetape_driver.gen_driver);
2453         if (error)
2454                 goto out_free_driver;
2455
2456         return 0;
2457
2458 out_free_driver:
2459         driver_unregister(&idetape_driver.gen_driver);
2460 out_free_class:
2461         class_destroy(idetape_sysfs_class);
2462 out:
2463         return error;
2464 }
2465
2466 MODULE_ALIAS("ide:*m-tape*");
2467 module_init(idetape_init);
2468 module_exit(idetape_exit);
2469 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2470 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2471 MODULE_LICENSE("GPL");