drivers/scsi/scsi_error.c

   1 /*
   2  *  scsi_error.c Copyright (C) 1997 Eric Youngdale
   3  *
   4  *  SCSI error/timeout handling
   5  *      Initial versions: Eric Youngdale.  Based upon conversations with
   6  *                        Leonard Zubkoff and David Miller at Linux Expo,
   7  *                        ideas originating from all over the place.
   8  *
   9  *      Restructured scsi_unjam_host and associated functions.
  10  *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  11  *
  12  *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
  13  *      minor  cleanups.
  14  *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/timer.h>
  20 #include <linux/string.h>
  21 #include <linux/slab.h>
  22 #include <linux/kernel.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/delay.h>
  26
  27 #include <scsi/scsi.h>
  28 #include <scsi/scsi_dbg.h>
  29 #include <scsi/scsi_device.h>
  30 #include <scsi/scsi_eh.h>
  31 #include <scsi/scsi_host.h>
  32 #include <scsi/scsi_ioctl.h>
  33 #include <scsi/scsi_request.h>
  34
  35 #include "scsi_priv.h"
  36 #include "scsi_logging.h"
  37
  38 #define SENSE_TIMEOUT           (10*HZ)
  39 #define START_UNIT_TIMEOUT      (30*HZ)
  40
  41 /*
  42  * These should *probably* be handled by the host itself.
  43  * Since it is allowed to sleep, it probably should.
  44  */
  45 #define BUS_RESET_SETTLE_TIME   (10)
  46 #define HOST_RESET_SETTLE_TIME  (10)
  47
  48 /* called with shost->host_lock held */
  49 void scsi_eh_wakeup(struct Scsi_Host *shost)
  50 {
  51         if (shost->host_busy == shost->host_failed) {
  52                 up(shost->eh_wait);
  53                 SCSI_LOG_ERROR_RECOVERY(5,
  54                                 printk("Waking error handler thread\n"));
  55         }
  56 }
  57
  58 /**
  59  * scsi_eh_scmd_add - add scsi cmd to error handling.
  60  * @scmd:       scmd to run eh on.
  61  * @eh_flag:    optional SCSI_EH flag.
  62  *
  63  * Return value:
  64  *      0 on failure.
  65  **/
  66 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  67 {
  68         struct Scsi_Host *shost = scmd->device->host;
  69         unsigned long flags;
  70
  71         if (shost->eh_wait == NULL)
  72                 return 0;
  73
  74         spin_lock_irqsave(shost->host_lock, flags);
  75
  76         scmd->eh_eflags |= eh_flag;
  77         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
  78         set_bit(SHOST_RECOVERY, &shost->shost_state);
  79         shost->host_failed++;
  80         scsi_eh_wakeup(shost);
  81         spin_unlock_irqrestore(shost->host_lock, flags);
  82         return 1;
  83 }
  84
  85 /**
  86  * scsi_add_timer - Start timeout timer for a single scsi command.
  87  * @scmd:       scsi command that is about to start running.
  88  * @timeout:    amount of time to allow this command to run.
  89  * @complete:   timeout function to call if timer isn't canceled.
  90  *
  91  * Notes:
  92  *    This should be turned into an inline function.  Each scsi command
  93  *    has its own timer, and as it is added to the queue, we set up the
  94  *    timer.  When the command completes, we cancel the timer.
  95  **/
  96 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
  97                     void (*complete)(struct scsi_cmnd *))
  98 {
  99
 100         /*
 101          * If the clock was already running for this command, then
 102          * first delete the timer.  The timer handling code gets rather
 103          * confused if we don't do this.
 104          */
 105         if (scmd->eh_timeout.function)
 106                 del_timer(&scmd->eh_timeout);
 107
 108         scmd->eh_timeout.data = (unsigned long)scmd;
 109         scmd->eh_timeout.expires = jiffies + timeout;
 110         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
 111
 112         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
 113                                           " %d, (%p)\n", __FUNCTION__,
 114                                           scmd, timeout, complete));
 115
 116         add_timer(&scmd->eh_timeout);
 117 }
 118 EXPORT_SYMBOL(scsi_add_timer);
 119
 120 /**
 121  * scsi_delete_timer - Delete/cancel timer for a given function.
 122  * @scmd:       Cmd that we are canceling timer for
 123  *
 124  * Notes:
 125  *     This should be turned into an inline function.
 126  *
 127  * Return value:
 128  *     1 if we were able to detach the timer.  0 if we blew it, and the
 129  *     timer function has already started to run.
 130  **/
 131 int scsi_delete_timer(struct scsi_cmnd *scmd)
 132 {
 133         int rtn;
 134
 135         rtn = del_timer(&scmd->eh_timeout);
 136
 137         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
 138                                          " rtn: %d\n", __FUNCTION__,
 139                                          scmd, rtn));
 140
 141         scmd->eh_timeout.data = (unsigned long)NULL;
 142         scmd->eh_timeout.function = NULL;
 143
 144         return rtn;
 145 }
 146 EXPORT_SYMBOL(scsi_delete_timer);
 147
 148 /**
 149  * scsi_times_out - Timeout function for normal scsi commands.
 150  * @scmd:       Cmd that is timing out.
 151  *
 152  * Notes:
 153  *     We do not need to lock this.  There is the potential for a race
 154  *     only in that the normal completion handling might run, but if the
 155  *     normal completion function determines that the timer has already
 156  *     fired, then it mustn't do anything.
 157  **/
 158 void scsi_times_out(struct scsi_cmnd *scmd)
 159 {
 160         scsi_log_completion(scmd, TIMEOUT_ERROR);
 161
 162         if (scmd->device->host->hostt->eh_timed_out)
 163                 switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
 164                 case EH_HANDLED:
 165                         __scsi_done(scmd);
 166                         return;
 167                 case EH_RESET_TIMER:
 168                         /* This allows a single retry even of a command
 169                          * with allowed == 0 */
 170                         if (scmd->retries++ > scmd->allowed)
 171                                 break;
 172                         scsi_add_timer(scmd, scmd->timeout_per_command,
 173                                        scsi_times_out);
 174                         return;
 175                 case EH_NOT_HANDLED:
 176                         break;
 177                 }
 178
 179         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 180                 panic("Error handler thread not present at %p %p %s %d",
 181                       scmd, scmd->device->host, __FILE__, __LINE__);
 182         }
 183 }
 184
 185 /**
 186  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 187  * @sdev:       Device on which we are performing recovery.
 188  *
 189  * Description:
 190  *     We block until the host is out of error recovery, and then check to
 191  *     see whether the host or the device is offline.
 192  *
 193  * Return value:
 194  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 195  **/
 196 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 197 {
 198         int online;
 199
 200         wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state)));
 201
 202         online = scsi_device_online(sdev);
 203
 204         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
 205                                           online));
 206
 207         return online;
 208 }
 209 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 210
 211 #ifdef CONFIG_SCSI_LOGGING
 212 /**
 213  * scsi_eh_prt_fail_stats - Log info on failures.
 214  * @shost:      scsi host being recovered.
 215  * @work_q:     Queue of scsi cmds to process.
 216  **/
 217 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 218                                           struct list_head *work_q)
 219 {
 220         struct scsi_cmnd *scmd;
 221         struct scsi_device *sdev;
 222         int total_failures = 0;
 223         int cmd_failed = 0;
 224         int cmd_cancel = 0;
 225         int devices_failed = 0;
 226
 227         shost_for_each_device(sdev, shost) {
 228                 list_for_each_entry(scmd, work_q, eh_entry) {
 229                         if (scmd->device == sdev) {
 230                                 ++total_failures;
 231                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 232                                         ++cmd_cancel;
 233                                 else
 234                                         ++cmd_failed;
 235                         }
 236                 }
 237
 238                 if (cmd_cancel || cmd_failed) {
 239                         SCSI_LOG_ERROR_RECOVERY(3,
 240                                 printk("%s: %d:%d:%d:%d cmds failed: %d,"
 241                                        " cancel: %d\n",
 242                                        __FUNCTION__, shost->host_no,
 243                                        sdev->channel, sdev->id, sdev->lun,
 244                                        cmd_failed, cmd_cancel));
 245                         cmd_cancel = 0;
 246                         cmd_failed = 0;
 247                         ++devices_failed;
 248                 }
 249         }
 250
 251         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 252                                           " devices require eh work\n",
 253                                   total_failures, devices_failed));
 254 }
 255 #endif
 256
 257 /**
 258  * scsi_check_sense - Examine scsi cmd sense
 259  * @scmd:       Cmd to have sense checked.
 260  *
 261  * Return value:
 262  *      SUCCESS or FAILED or NEEDS_RETRY
 263  *
 264  * Notes:
 265  *      When a deferred error is detected the current command has
 266  *      not been executed and needs retrying.
 267  **/
 268 static int scsi_check_sense(struct scsi_cmnd *scmd)
 269 {
 270         struct scsi_sense_hdr sshdr;
 271
 272         if (! scsi_command_normalize_sense(scmd, &sshdr))
 273                 return FAILED;  /* no valid sense data */
 274
 275         if (scsi_sense_is_deferred(&sshdr))
 276                 return NEEDS_RETRY;
 277
 278         /*
 279          * Previous logic looked for FILEMARK, EOM or ILI which are
 280          * mainly associated with tapes and returned SUCCESS.
 281          */
 282         if (sshdr.response_code == 0x70) {
 283                 /* fixed format */
 284                 if (scmd->sense_buffer[2] & 0xe0)
 285                         return SUCCESS;
 286         } else {
 287                 /*
 288                  * descriptor format: look for "stream commands sense data
 289                  * descriptor" (see SSC-3). Assume single sense data
 290                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 291                  */
 292                 if ((sshdr.additional_length > 3) &&
 293                     (scmd->sense_buffer[8] == 0x4) &&
 294                     (scmd->sense_buffer[11] & 0xe0))
 295                         return SUCCESS;
 296         }
 297
 298         switch (sshdr.sense_key) {
 299         case NO_SENSE:
 300                 return SUCCESS;
 301         case RECOVERED_ERROR:
 302                 return /* soft_error */ SUCCESS;
 303
 304         case ABORTED_COMMAND:
 305                 return NEEDS_RETRY;
 306         case NOT_READY:
 307         case UNIT_ATTENTION:
 308                 /*
 309                  * if we are expecting a cc/ua because of a bus reset that we
 310                  * performed, treat this just as a retry.  otherwise this is
 311                  * information that we should pass up to the upper-level driver
 312                  * so that we can deal with it there.
 313                  */
 314                 if (scmd->device->expecting_cc_ua) {
 315                         scmd->device->expecting_cc_ua = 0;
 316                         return NEEDS_RETRY;
 317                 }
 318                 /*
 319                  * if the device is in the process of becoming ready, we
 320                  * should retry.
 321                  */
 322                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 323                         return NEEDS_RETRY;
 324                 /*
 325                  * if the device is not started, we need to wake
 326                  * the error handler to start the motor
 327                  */
 328                 if (scmd->device->allow_restart &&
 329                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 330                         return FAILED;
 331                 return SUCCESS;
 332
 333                 /* these three are not supported */
 334         case COPY_ABORTED:
 335         case VOLUME_OVERFLOW:
 336         case MISCOMPARE:
 337                 return SUCCESS;
 338
 339         case MEDIUM_ERROR:
 340                 return NEEDS_RETRY;
 341
 342         case HARDWARE_ERROR:
 343                 if (scmd->device->retry_hwerror)
 344                         return NEEDS_RETRY;
 345                 else
 346                         return SUCCESS;
 347
 348         case ILLEGAL_REQUEST:
 349         case BLANK_CHECK:
 350         case DATA_PROTECT:
 351         default:
 352                 return SUCCESS;
 353         }
 354 }
 355
 356 /**
 357  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 358  * @scmd:       SCSI cmd to examine.
 359  *
 360  * Notes:
 361  *    This is *only* called when we are examining the status of commands
 362  *    queued during error recovery.  the main difference here is that we
 363  *    don't allow for the possibility of retries here, and we are a lot
 364  *    more restrictive about what we consider acceptable.
 365  **/
 366 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 367 {
 368         /*
 369          * first check the host byte, to see if there is anything in there
 370          * that would indicate what we need to do.
 371          */
 372         if (host_byte(scmd->result) == DID_RESET) {
 373                 /*
 374                  * rats.  we are already in the error handler, so we now
 375                  * get to try and figure out what to do next.  if the sense
 376                  * is valid, we have a pretty good idea of what to do.
 377                  * if not, we mark it as FAILED.
 378                  */
 379                 return scsi_check_sense(scmd);
 380         }
 381         if (host_byte(scmd->result) != DID_OK)
 382                 return FAILED;
 383
 384         /*
 385          * next, check the message byte.
 386          */
 387         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 388                 return FAILED;
 389
 390         /*
 391          * now, check the status byte to see if this indicates
 392          * anything special.
 393          */
 394         switch (status_byte(scmd->result)) {
 395         case GOOD:
 396         case COMMAND_TERMINATED:
 397                 return SUCCESS;
 398         case CHECK_CONDITION:
 399                 return scsi_check_sense(scmd);
 400         case CONDITION_GOOD:
 401         case INTERMEDIATE_GOOD:
 402         case INTERMEDIATE_C_GOOD:
 403                 /*
 404                  * who knows?  FIXME(eric)
 405                  */
 406                 return SUCCESS;
 407         case BUSY:
 408         case QUEUE_FULL:
 409         case RESERVATION_CONFLICT:
 410         default:
 411                 return FAILED;
 412         }
 413         return FAILED;
 414 }
 415
 416 /**
 417  * scsi_eh_times_out - timeout function for error handling.
 418  * @scmd:       Cmd that is timing out.
 419  *
 420  * Notes:
 421  *    During error handling, the kernel thread will be sleeping waiting
 422  *    for some action to complete on the device.  our only job is to
 423  *    record that it timed out, and to wake up the thread.
 424  **/
 425 static void scsi_eh_times_out(struct scsi_cmnd *scmd)
 426 {
 427         scmd->eh_eflags |= SCSI_EH_REC_TIMEOUT;
 428         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
 429                                           scmd));
 430
 431         up(scmd->device->host->eh_action);
 432 }
 433
 434 /**
 435  * scsi_eh_done - Completion function for error handling.
 436  * @scmd:       Cmd that is done.
 437  **/
 438 static void scsi_eh_done(struct scsi_cmnd *scmd)
 439 {
 440         /*
 441          * if the timeout handler is already running, then just set the
 442          * flag which says we finished late, and return.  we have no
 443          * way of stopping the timeout handler from running, so we must
 444          * always defer to it.
 445          */
 446         if (del_timer(&scmd->eh_timeout)) {
 447                 scmd->request->rq_status = RQ_SCSI_DONE;
 448
 449                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
 450                                            __FUNCTION__, scmd, scmd->result));
 451
 452                 up(scmd->device->host->eh_action);
 453         }
 454 }
 455
 456 /**
 457  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
 458  * @scmd:       SCSI Cmd to send.
 459  * @timeout:    Timeout for cmd.
 460  *
 461  * Notes:
 462  *    The initialization of the structures is quite a bit different in
 463  *    this case, and furthermore, there is a different completion handler
 464  *    vs scsi_dispatch_cmd.
 465  * Return value:
 466  *    SUCCESS or FAILED or NEEDS_RETRY
 467  **/
 468 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
 469 {
 470         struct scsi_device *sdev = scmd->device;
 471         struct Scsi_Host *shost = sdev->host;
 472         DECLARE_MUTEX_LOCKED(sem);
 473         unsigned long flags;
 474         int rtn = SUCCESS;
 475
 476         /*
 477          * we will use a queued command if possible, otherwise we will
 478          * emulate the queuing and calling of completion function ourselves.
 479          */
 480         if (sdev->scsi_level <= SCSI_2)
 481                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 482                         (sdev->lun << 5 & 0xe0);
 483
 484         scsi_add_timer(scmd, timeout, scsi_eh_times_out);
 485
 486         /*
 487          * set up the semaphore so we wait for the command to complete.
 488          */
 489         shost->eh_action = &sem;
 490         scmd->request->rq_status = RQ_SCSI_BUSY;
 491
 492         spin_lock_irqsave(shost->host_lock, flags);
 493         scsi_log_send(scmd);
 494         shost->hostt->queuecommand(scmd, scsi_eh_done);
 495         spin_unlock_irqrestore(shost->host_lock, flags);
 496
 497         down(&sem);
 498         scsi_log_completion(scmd, SUCCESS);
 499
 500         shost->eh_action = NULL;
 501
 502         /*
 503          * see if timeout.  if so, tell the host to forget about it.
 504          * in other words, we don't want a callback any more.
 505          */
 506         if (scmd->eh_eflags & SCSI_EH_REC_TIMEOUT) {
 507                 scmd->eh_eflags &= ~SCSI_EH_REC_TIMEOUT;
 508
 509                 /*
 510                  * as far as the low level driver is
 511                  * concerned, this command is still active, so
 512                  * we must give the low level driver a chance
 513                  * to abort it. (db)
 514                  *
 515                  * FIXME(eric) - we are not tracking whether we could
 516                  * abort a timed out command or not.  not sure how
 517                  * we should treat them differently anyways.
 518                  */
 519                 if (shost->hostt->eh_abort_handler)
 520                         shost->hostt->eh_abort_handler(scmd);
 521
 522                 scmd->request->rq_status = RQ_SCSI_DONE;
 523                 rtn = FAILED;
 524         }
 525
 526         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
 527                                           __FUNCTION__, scmd, rtn));
 528
 529         /*
 530          * now examine the actual status codes to see whether the command
 531          * actually did complete normally.
 532          */
 533         if (rtn == SUCCESS) {
 534                 rtn = scsi_eh_completed_normally(scmd);
 535                 SCSI_LOG_ERROR_RECOVERY(3,
 536                         printk("%s: scsi_eh_completed_normally %x\n",
 537                                __FUNCTION__, rtn));
 538                 switch (rtn) {
 539                 case SUCCESS:
 540                 case NEEDS_RETRY:
 541                 case FAILED:
 542                         break;
 543                 default:
 544                         rtn = FAILED;
 545                         break;
 546                 }
 547         }
 548
 549         return rtn;
 550 }
 551
 552 /**
 553  * scsi_request_sense - Request sense data from a particular target.
 554  * @scmd:       SCSI cmd for request sense.
 555  *
 556  * Notes:
 557  *    Some hosts automatically obtain this information, others require
 558  *    that we obtain it on our own. This function will *not* return until
 559  *    the command either times out, or it completes.
 560  **/
 561 static int scsi_request_sense(struct scsi_cmnd *scmd)
 562 {
 563         static unsigned char generic_sense[6] =
 564         {REQUEST_SENSE, 0, 0, 0, 252, 0};
 565         unsigned char *scsi_result;
 566         int saved_result;
 567         int rtn;
 568
 569         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
 570
 571         scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
 572
 573
 574         if (unlikely(!scsi_result)) {
 575                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
 576                        __FUNCTION__);
 577                 return FAILED;
 578         }
 579
 580         /*
 581          * zero the sense buffer.  some host adapters automatically always
 582          * request sense, so it is not a good idea that
 583          * scmd->request_buffer and scmd->sense_buffer point to the same
 584          * address (db).  0 is not a valid sense code.
 585          */
 586         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 587         memset(scsi_result, 0, 252);
 588
 589         saved_result = scmd->result;
 590         scmd->request_buffer = scsi_result;
 591         scmd->request_bufflen = 252;
 592         scmd->use_sg = 0;
 593         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 594         scmd->sc_data_direction = DMA_FROM_DEVICE;
 595         scmd->underflow = 0;
 596
 597         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 598
 599         /* last chance to have valid sense data */
 600         if(!SCSI_SENSE_VALID(scmd)) {
 601                 memcpy(scmd->sense_buffer, scmd->request_buffer,
 602                        sizeof(scmd->sense_buffer));
 603         }
 604
 605         kfree(scsi_result);
 606
 607         /*
 608          * when we eventually call scsi_finish, we really wish to complete
 609          * the original request, so let's restore the original data. (db)
 610          */
 611         scsi_setup_cmd_retry(scmd);
 612         scmd->result = saved_result;
 613         return rtn;
 614 }
 615
 616 /**
 617  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 618  * @scmd:       Original SCSI cmd that eh has finished.
 619  * @done_q:     Queue for processed commands.
 620  *
 621  * Notes:
 622  *    We don't want to use the normal command completion while we are are
 623  *    still handling errors - it may cause other commands to be queued,
 624  *    and that would disturb what we are doing.  thus we really want to
 625  *    keep a list of pending commands for final completion, and once we
 626  *    are ready to leave error handling we handle completion for real.
 627  **/
 628 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
 629                                struct list_head *done_q)
 630 {
 631         scmd->device->host->host_failed--;
 632         scmd->eh_eflags = 0;
 633
 634         /*
 635          * set this back so that the upper level can correctly free up
 636          * things.
 637          */
 638         scsi_setup_cmd_retry(scmd);
 639         list_move_tail(&scmd->eh_entry, done_q);
 640 }
 641
 642 /**
 643  * scsi_eh_get_sense - Get device sense data.
 644  * @work_q:     Queue of commands to process.
 645  * @done_q:     Queue of proccessed commands..
 646  *
 647  * Description:
 648  *    See if we need to request sense information.  if so, then get it
 649  *    now, so we have a better idea of what to do.
 650  *
 651  * Notes:
 652  *    This has the unfortunate side effect that if a shost adapter does
 653  *    not automatically request sense information, that we end up shutting
 654  *    it down before we request it.
 655  *
 656  *    All drivers should request sense information internally these days,
 657  *    so for now all I have to say is tough noogies if you end up in here.
 658  *
 659  *    XXX: Long term this code should go away, but that needs an audit of
 660  *         all LLDDs first.
 661  **/
 662 static int scsi_eh_get_sense(struct list_head *work_q,
 663                              struct list_head *done_q)
 664 {
 665         struct list_head *lh, *lh_sf;
 666         struct scsi_cmnd *scmd;
 667         int rtn;
 668
 669         list_for_each_safe(lh, lh_sf, work_q) {
 670                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 671                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 672                     SCSI_SENSE_VALID(scmd))
 673                         continue;
 674
 675                 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
 676                                                   " for id: %d\n",
 677                                                   current->comm,
 678                                                   scmd->device->id));
 679                 rtn = scsi_request_sense(scmd);
 680                 if (rtn != SUCCESS)
 681                         continue;
 682
 683                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 684                                                   " result %x\n", scmd,
 685                                                   scmd->result));
 686                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 687
 688                 rtn = scsi_decide_disposition(scmd);
 689
 690                 /*
 691                  * if the result was normal, then just pass it along to the
 692                  * upper level.
 693                  */
 694                 if (rtn == SUCCESS)
 695                         /* we don't want this command reissued, just
 696                          * finished with the sense data, so set
 697                          * retries to the max allowed to ensure it
 698                          * won't get reissued */
 699                         scmd->retries = scmd->allowed;
 700                 else if (rtn != NEEDS_RETRY)
 701                         continue;
 702
 703                 scsi_eh_finish_cmd(scmd, done_q);
 704         }
 705
 706         return list_empty(work_q);
 707 }
 708
 709 /**
 710  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 711  * @scmd:       SCSI cmd to abort from Lower Level.
 712  *
 713  * Notes:
 714  *    This function will not return until the user's completion function
 715  *    has been called.  there is no timeout on this operation.  if the
 716  *    author of the low-level driver wishes this operation to be timed,
 717  *    they can provide this facility themselves.  helper functions in
 718  *    scsi_error.c can be supplied to make this easier to do.
 719  **/
 720 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 721 {
 722         if (!scmd->device->host->hostt->eh_abort_handler)
 723                 return FAILED;
 724
 725         /*
 726          * scsi_done was called just after the command timed out and before
 727          * we had a chance to process it. (db)
 728          */
 729         if (scmd->serial_number == 0)
 730                 return SUCCESS;
 731         return scmd->device->host->hostt->eh_abort_handler(scmd);
 732 }
 733
 734 /**
 735  * scsi_eh_tur - Send TUR to device.
 736  * @scmd:       Scsi cmd to send TUR
 737  *
 738  * Return value:
 739  *    0 - Device is ready. 1 - Device NOT ready.
 740  **/
 741 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 742 {
 743         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 744         int retry_cnt = 1, rtn;
 745         int saved_result;
 746
 747 retry_tur:
 748         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
 749
 750         /*
 751          * zero the sense buffer.  the scsi spec mandates that any
 752          * untransferred sense data should be interpreted as being zero.
 753          */
 754         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 755
 756         saved_result = scmd->result;
 757         scmd->request_buffer = NULL;
 758         scmd->request_bufflen = 0;
 759         scmd->use_sg = 0;
 760         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 761         scmd->underflow = 0;
 762         scmd->sc_data_direction = DMA_NONE;
 763
 764         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 765
 766         /*
 767          * when we eventually call scsi_finish, we really wish to complete
 768          * the original request, so let's restore the original data. (db)
 769          */
 770         scsi_setup_cmd_retry(scmd);
 771         scmd->result = saved_result;
 772
 773         /*
 774          * hey, we are done.  let's look to see what happened.
 775          */
 776         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 777                 __FUNCTION__, scmd, rtn));
 778         if (rtn == SUCCESS)
 779                 return 0;
 780         else if (rtn == NEEDS_RETRY)
 781                 if (retry_cnt--)
 782                         goto retry_tur;
 783         return 1;
 784 }
 785
 786 /**
 787  * scsi_eh_abort_cmds - abort canceled commands.
 788  * @shost:      scsi host being recovered.
 789  * @eh_done_q:  list_head for processed commands.
 790  *
 791  * Decription:
 792  *    Try and see whether or not it makes sense to try and abort the
 793  *    running command.  this only works out to be the case if we have one
 794  *    command that has timed out.  if the command simply failed, it makes
 795  *    no sense to try and abort the command, since as far as the shost
 796  *    adapter is concerned, it isn't running.
 797  **/
 798 static int scsi_eh_abort_cmds(struct list_head *work_q,
 799                               struct list_head *done_q)
 800 {
 801         struct list_head *lh, *lh_sf;
 802         struct scsi_cmnd *scmd;
 803         int rtn;
 804
 805         list_for_each_safe(lh, lh_sf, work_q) {
 806                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 807                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 808                         continue;
 809                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 810                                                   "0x%p\n", current->comm,
 811                                                   scmd));
 812                 rtn = scsi_try_to_abort_cmd(scmd);
 813                 if (rtn == SUCCESS) {
 814                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 815                         if (!scsi_device_online(scmd->device) ||
 816                             !scsi_eh_tur(scmd)) {
 817                                 scsi_eh_finish_cmd(scmd, done_q);
 818                         }
 819
 820                 } else
 821                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 822                                                           " cmd failed:"
 823                                                           "0x%p\n",
 824                                                           current->comm,
 825                                                           scmd));
 826         }
 827
 828         return list_empty(work_q);
 829 }
 830
 831 /**
 832  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 833  * @scmd:       SCSI cmd used to send BDR
 834  *
 835  * Notes:
 836  *    There is no timeout for this operation.  if this operation is
 837  *    unreliable for a given host, then the host itself needs to put a
 838  *    timer on it, and set the host back to a consistent state prior to
 839  *    returning.
 840  **/
 841 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 842 {
 843         int rtn;
 844
 845         if (!scmd->device->host->hostt->eh_device_reset_handler)
 846                 return FAILED;
 847
 848         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 849         if (rtn == SUCCESS) {
 850                 scmd->device->was_reset = 1;
 851                 scmd->device->expecting_cc_ua = 1;
 852         }
 853
 854         return rtn;
 855 }
 856
 857 /**
 858  * scsi_eh_try_stu - Send START_UNIT to device.
 859  * @scmd:       Scsi cmd to send START_UNIT
 860  *
 861  * Return value:
 862  *    0 - Device is ready. 1 - Device NOT ready.
 863  **/
 864 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 865 {
 866         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 867         int rtn;
 868         int saved_result;
 869
 870         if (!scmd->device->allow_restart)
 871                 return 1;
 872
 873         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
 874
 875         /*
 876          * zero the sense buffer.  the scsi spec mandates that any
 877          * untransferred sense data should be interpreted as being zero.
 878          */
 879         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 880
 881         saved_result = scmd->result;
 882         scmd->request_buffer = NULL;
 883         scmd->request_bufflen = 0;
 884         scmd->use_sg = 0;
 885         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 886         scmd->underflow = 0;
 887         scmd->sc_data_direction = DMA_NONE;
 888
 889         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
 890
 891         /*
 892          * when we eventually call scsi_finish, we really wish to complete
 893          * the original request, so let's restore the original data. (db)
 894          */
 895         scsi_setup_cmd_retry(scmd);
 896         scmd->result = saved_result;
 897
 898         /*
 899          * hey, we are done.  let's look to see what happened.
 900          */
 901         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 902                 __FUNCTION__, scmd, rtn));
 903         if (rtn == SUCCESS)
 904                 return 0;
 905         return 1;
 906 }
 907
 908  /**
 909  * scsi_eh_stu - send START_UNIT if needed
 910  * @shost:      scsi host being recovered.
 911  * @eh_done_q:  list_head for processed commands.
 912  *
 913  * Notes:
 914  *    If commands are failing due to not ready, initializing command required,
 915  *      try revalidating the device, which will end up sending a start unit.
 916  **/
 917 static int scsi_eh_stu(struct Scsi_Host *shost,
 918                               struct list_head *work_q,
 919                               struct list_head *done_q)
 920 {
 921         struct list_head *lh, *lh_sf;
 922         struct scsi_cmnd *scmd, *stu_scmd;
 923         struct scsi_device *sdev;
 924
 925         shost_for_each_device(sdev, shost) {
 926                 stu_scmd = NULL;
 927                 list_for_each_entry(scmd, work_q, eh_entry)
 928                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 929                             scsi_check_sense(scmd) == FAILED ) {
 930                                 stu_scmd = scmd;
 931                                 break;
 932                         }
 933
 934                 if (!stu_scmd)
 935                         continue;
 936
 937                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 938                                                   " 0x%p\n", current->comm, sdev));
 939
 940                 if (!scsi_eh_try_stu(stu_scmd)) {
 941                         if (!scsi_device_online(sdev) ||
 942                             !scsi_eh_tur(stu_scmd)) {
 943                                 list_for_each_safe(lh, lh_sf, work_q) {
 944                                         scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 945                                         if (scmd->device == sdev)
 946                                                 scsi_eh_finish_cmd(scmd, done_q);
 947                                 }
 948                         }
 949                 } else {
 950                         SCSI_LOG_ERROR_RECOVERY(3,
 951                                                 printk("%s: START_UNIT failed to sdev:"
 952                                                        " 0x%p\n", current->comm, sdev));
 953                 }
 954         }
 955
 956         return list_empty(work_q);
 957 }
 958
 959
 960 /**
 961  * scsi_eh_bus_device_reset - send bdr if needed
 962  * @shost:      scsi host being recovered.
 963  * @eh_done_q:  list_head for processed commands.
 964  *
 965  * Notes:
 966  *    Try a bus device reset.  still, look to see whether we have multiple
 967  *    devices that are jammed or not - if we have multiple devices, it
 968  *    makes no sense to try bus_device_reset - we really would need to try
 969  *    a bus_reset instead.
 970  **/
 971 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
 972                                     struct list_head *work_q,
 973                                     struct list_head *done_q)
 974 {
 975         struct list_head *lh, *lh_sf;
 976         struct scsi_cmnd *scmd, *bdr_scmd;
 977         struct scsi_device *sdev;
 978         int rtn;
 979
 980         shost_for_each_device(sdev, shost) {
 981                 bdr_scmd = NULL;
 982                 list_for_each_entry(scmd, work_q, eh_entry)
 983                         if (scmd->device == sdev) {
 984                                 bdr_scmd = scmd;
 985                                 break;
 986                         }
 987
 988                 if (!bdr_scmd)
 989                         continue;
 990
 991                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
 992                                                   " 0x%p\n", current->comm,
 993                                                   sdev));
 994                 rtn = scsi_try_bus_device_reset(bdr_scmd);
 995                 if (rtn == SUCCESS) {
 996                         if (!scsi_device_online(sdev) ||
 997                             !scsi_eh_tur(bdr_scmd)) {
 998                                 list_for_each_safe(lh, lh_sf,
 999                                                    work_q) {
1000                                         scmd = list_entry(lh, struct
1001                                                           scsi_cmnd,
1002                                                           eh_entry);
1003                                         if (scmd->device == sdev)
1004                                                 scsi_eh_finish_cmd(scmd,
1005                                                                    done_q);
1006                                 }
1007                         }
1008                 } else {
1009                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1010                                                           " failed sdev:"
1011                                                           "0x%p\n",
1012                                                           current->comm,
1013                                                            sdev));
1014                 }
1015         }
1016
1017         return list_empty(work_q);
1018 }
1019
1020 /**
1021  * scsi_try_bus_reset - ask host to perform a bus reset
1022  * @scmd:       SCSI cmd to send bus reset.
1023  **/
1024 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
1025 {
1026         unsigned long flags;
1027         int rtn;
1028
1029         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1030                                           __FUNCTION__));
1031
1032         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1033                 return FAILED;
1034
1035         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1036
1037         if (rtn == SUCCESS) {
1038                 if (!scmd->device->host->hostt->skip_settle_delay)
1039                         ssleep(BUS_RESET_SETTLE_TIME);
1040                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1041                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1042                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1043         }
1044
1045         return rtn;
1046 }
1047
1048 /**
1049  * scsi_try_host_reset - ask host adapter to reset itself
1050  * @scmd:       SCSI cmd to send hsot reset.
1051  **/
1052 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1053 {
1054         unsigned long flags;
1055         int rtn;
1056
1057         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1058                                           __FUNCTION__));
1059
1060         if (!scmd->device->host->hostt->eh_host_reset_handler)
1061                 return FAILED;
1062
1063         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1064
1065         if (rtn == SUCCESS) {
1066                 if (!scmd->device->host->hostt->skip_settle_delay)
1067                         ssleep(HOST_RESET_SETTLE_TIME);
1068                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1069                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1070                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1071         }
1072
1073         return rtn;
1074 }
1075
1076 /**
1077  * scsi_eh_bus_reset - send a bus reset
1078  * @shost:      scsi host being recovered.
1079  * @eh_done_q:  list_head for processed commands.
1080  **/
1081 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1082                              struct list_head *work_q,
1083                              struct list_head *done_q)
1084 {
1085         struct list_head *lh, *lh_sf;
1086         struct scsi_cmnd *scmd;
1087         struct scsi_cmnd *chan_scmd;
1088         unsigned int channel;
1089         int rtn;
1090
1091         /*
1092          * we really want to loop over the various channels, and do this on
1093          * a channel by channel basis.  we should also check to see if any
1094          * of the failed commands are on soft_reset devices, and if so, skip
1095          * the reset.
1096          */
1097
1098         for (channel = 0; channel <= shost->max_channel; channel++) {
1099                 chan_scmd = NULL;
1100                 list_for_each_entry(scmd, work_q, eh_entry) {
1101                         if (channel == scmd->device->channel) {
1102                                 chan_scmd = scmd;
1103                                 break;
1104                                 /*
1105                                  * FIXME add back in some support for
1106                                  * soft_reset devices.
1107                                  */
1108                         }
1109                 }
1110
1111                 if (!chan_scmd)
1112                         continue;
1113                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1114                                                   " %d\n", current->comm,
1115                                                   channel));
1116                 rtn = scsi_try_bus_reset(chan_scmd);
1117                 if (rtn == SUCCESS) {
1118                         list_for_each_safe(lh, lh_sf, work_q) {
1119                                 scmd = list_entry(lh, struct scsi_cmnd,
1120                                                   eh_entry);
1121                                 if (channel == scmd->device->channel)
1122                                         if (!scsi_device_online(scmd->device) ||
1123                                             !scsi_eh_tur(scmd))
1124                                                 scsi_eh_finish_cmd(scmd,
1125                                                                    done_q);
1126                         }
1127                 } else {
1128                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1129                                                           " failed chan: %d\n",
1130                                                           current->comm,
1131                                                           channel));
1132                 }
1133         }
1134         return list_empty(work_q);
1135 }
1136
1137 /**
1138  * scsi_eh_host_reset - send a host reset
1139  * @work_q:     list_head for processed commands.
1140  * @done_q:     list_head for processed commands.
1141  **/
1142 static int scsi_eh_host_reset(struct list_head *work_q,
1143                               struct list_head *done_q)
1144 {
1145         int rtn;
1146         struct list_head *lh, *lh_sf;
1147         struct scsi_cmnd *scmd;
1148
1149         if (!list_empty(work_q)) {
1150                 scmd = list_entry(work_q->next,
1151                                   struct scsi_cmnd, eh_entry);
1152
1153                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1154                                                   , current->comm));
1155
1156                 rtn = scsi_try_host_reset(scmd);
1157                 if (rtn == SUCCESS) {
1158                         list_for_each_safe(lh, lh_sf, work_q) {
1159                                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1160                                 if (!scsi_device_online(scmd->device) ||
1161                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1162                                     !scsi_eh_tur(scmd))
1163                                         scsi_eh_finish_cmd(scmd, done_q);
1164                         }
1165                 } else {
1166                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1167                                                           " failed\n",
1168                                                           current->comm));
1169                 }
1170         }
1171         return list_empty(work_q);
1172 }
1173
1174 /**
1175  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1176  * @work_q:     list_head for processed commands.
1177  * @done_q:     list_head for processed commands.
1178  *
1179  **/
1180 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1181                                   struct list_head *done_q)
1182 {
1183         struct list_head *lh, *lh_sf;
1184         struct scsi_cmnd *scmd;
1185
1186         list_for_each_safe(lh, lh_sf, work_q) {
1187                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1188                 printk(KERN_INFO "scsi: Device offlined - not"
1189                                 " ready after error recovery: host"
1190                                 " %d channel %d id %d lun %d\n",
1191                                 scmd->device->host->host_no,
1192                                 scmd->device->channel,
1193                                 scmd->device->id,
1194                                 scmd->device->lun);
1195                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1196                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1197                         /*
1198                          * FIXME: Handle lost cmds.
1199                          */
1200                 }
1201                 scsi_eh_finish_cmd(scmd, done_q);
1202         }
1203         return;
1204 }
1205
1206 /**
1207  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1208  * @scmd:       SCSI cmd to examine.
1209  *
1210  * Notes:
1211  *    This is *only* called when we are examining the status after sending
1212  *    out the actual data command.  any commands that are queued for error
1213  *    recovery (e.g. test_unit_ready) do *not* come through here.
1214  *
1215  *    When this routine returns failed, it means the error handler thread
1216  *    is woken.  In cases where the error code indicates an error that
1217  *    doesn't require the error handler read (i.e. we don't need to
1218  *    abort/reset), this function should return SUCCESS.
1219  **/
1220 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1221 {
1222         int rtn;
1223
1224         /*
1225          * if the device is offline, then we clearly just pass the result back
1226          * up to the top level.
1227          */
1228         if (!scsi_device_online(scmd->device)) {
1229                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1230                                                   " as SUCCESS\n",
1231                                                   __FUNCTION__));
1232                 return SUCCESS;
1233         }
1234
1235         /*
1236          * first check the host byte, to see if there is anything in there
1237          * that would indicate what we need to do.
1238          */
1239         switch (host_byte(scmd->result)) {
1240         case DID_PASSTHROUGH:
1241                 /*
1242                  * no matter what, pass this through to the upper layer.
1243                  * nuke this special code so that it looks like we are saying
1244                  * did_ok.
1245                  */
1246                 scmd->result &= 0xff00ffff;
1247                 return SUCCESS;
1248         case DID_OK:
1249                 /*
1250                  * looks good.  drop through, and check the next byte.
1251                  */
1252                 break;
1253         case DID_NO_CONNECT:
1254         case DID_BAD_TARGET:
1255         case DID_ABORT:
1256                 /*
1257                  * note - this means that we just report the status back
1258                  * to the top level driver, not that we actually think
1259                  * that it indicates SUCCESS.
1260                  */
1261                 return SUCCESS;
1262                 /*
1263                  * when the low level driver returns did_soft_error,
1264                  * it is responsible for keeping an internal retry counter
1265                  * in order to avoid endless loops (db)
1266                  *
1267                  * actually this is a bug in this function here.  we should
1268                  * be mindful of the maximum number of retries specified
1269                  * and not get stuck in a loop.
1270                  */
1271         case DID_SOFT_ERROR:
1272                 goto maybe_retry;
1273         case DID_IMM_RETRY:
1274                 return NEEDS_RETRY;
1275
1276         case DID_REQUEUE:
1277                 return ADD_TO_MLQUEUE;
1278
1279         case DID_ERROR:
1280                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1281                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1282                         /*
1283                          * execute reservation conflict processing code
1284                          * lower down
1285                          */
1286                         break;
1287                 /* fallthrough */
1288
1289         case DID_BUS_BUSY:
1290         case DID_PARITY:
1291                 goto maybe_retry;
1292         case DID_TIME_OUT:
1293                 /*
1294                  * when we scan the bus, we get timeout messages for
1295                  * these commands if there is no device available.
1296                  * other hosts report did_no_connect for the same thing.
1297                  */
1298                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1299                      scmd->cmnd[0] == INQUIRY)) {
1300                         return SUCCESS;
1301                 } else {
1302                         return FAILED;
1303                 }
1304         case DID_RESET:
1305                 return SUCCESS;
1306         default:
1307                 return FAILED;
1308         }
1309
1310         /*
1311          * next, check the message byte.
1312          */
1313         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1314                 return FAILED;
1315
1316         /*
1317          * check the status byte to see if this indicates anything special.
1318          */
1319         switch (status_byte(scmd->result)) {
1320         case QUEUE_FULL:
1321                 /*
1322                  * the case of trying to send too many commands to a
1323                  * tagged queueing device.
1324                  */
1325         case BUSY:
1326                 /*
1327                  * device can't talk to us at the moment.  Should only
1328                  * occur (SAM-3) when the task queue is empty, so will cause
1329                  * the empty queue handling to trigger a stall in the
1330                  * device.
1331                  */
1332                 return ADD_TO_MLQUEUE;
1333         case GOOD:
1334         case COMMAND_TERMINATED:
1335         case TASK_ABORTED:
1336                 return SUCCESS;
1337         case CHECK_CONDITION:
1338                 rtn = scsi_check_sense(scmd);
1339                 if (rtn == NEEDS_RETRY)
1340                         goto maybe_retry;
1341                 /* if rtn == FAILED, we have no sense information;
1342                  * returning FAILED will wake the error handler thread
1343                  * to collect the sense and redo the decide
1344                  * disposition */
1345                 return rtn;
1346         case CONDITION_GOOD:
1347         case INTERMEDIATE_GOOD:
1348         case INTERMEDIATE_C_GOOD:
1349         case ACA_ACTIVE:
1350                 /*
1351                  * who knows?  FIXME(eric)
1352                  */
1353                 return SUCCESS;
1354
1355         case RESERVATION_CONFLICT:
1356                 printk(KERN_INFO "scsi: reservation conflict: host"
1357                                 " %d channel %d id %d lun %d\n",
1358                        scmd->device->host->host_no, scmd->device->channel,
1359                        scmd->device->id, scmd->device->lun);
1360                 return SUCCESS; /* causes immediate i/o error */
1361         default:
1362                 return FAILED;
1363         }
1364         return FAILED;
1365
1366       maybe_retry:
1367
1368         /* we requeue for retry because the error was retryable, and
1369          * the request was not marked fast fail.  Note that above,
1370          * even if the request is marked fast fail, we still requeue
1371          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1372         if ((++scmd->retries) < scmd->allowed
1373             && !blk_noretry_request(scmd->request)) {
1374                 return NEEDS_RETRY;
1375         } else {
1376                 /*
1377                  * no more retries - report this one back to upper level.
1378                  */
1379                 return SUCCESS;
1380         }
1381 }
1382
1383 /**
1384  * scsi_eh_lock_done - done function for eh door lock request
1385  * @scmd:       SCSI command block for the door lock request
1386  *
1387  * Notes:
1388  *      We completed the asynchronous door lock request, and it has either
1389  *      locked the door or failed.  We must free the command structures
1390  *      associated with this request.
1391  **/
1392 static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
1393 {
1394         struct scsi_request *sreq = scmd->sc_request;
1395
1396         scsi_release_request(sreq);
1397 }
1398
1399
1400 /**
1401  * scsi_eh_lock_door - Prevent medium removal for the specified device
1402  * @sdev:       SCSI device to prevent medium removal
1403  *
1404  * Locking:
1405  *      We must be called from process context; scsi_allocate_request()
1406  *      may sleep.
1407  *
1408  * Notes:
1409  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1410  *      head of the devices request queue, and continue.
1411  *
1412  * Bugs:
1413  *      scsi_allocate_request() may sleep waiting for existing requests to
1414  *      be processed.  However, since we haven't kicked off any request
1415  *      processing for this host, this may deadlock.
1416  *
1417  *      If scsi_allocate_request() fails for what ever reason, we
1418  *      completely forget to lock the door.
1419  **/
1420 static void scsi_eh_lock_door(struct scsi_device *sdev)
1421 {
1422         struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
1423
1424         if (unlikely(!sreq)) {
1425                 printk(KERN_ERR "%s: request allocate failed,"
1426                        "prevent media removal cmd not sent\n", __FUNCTION__);
1427                 return;
1428         }
1429
1430         sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1431         sreq->sr_cmnd[1] = 0;
1432         sreq->sr_cmnd[2] = 0;
1433         sreq->sr_cmnd[3] = 0;
1434         sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
1435         sreq->sr_cmnd[5] = 0;
1436         sreq->sr_data_direction = DMA_NONE;
1437         sreq->sr_bufflen = 0;
1438         sreq->sr_buffer = NULL;
1439         sreq->sr_allowed = 5;
1440         sreq->sr_done = scsi_eh_lock_done;
1441         sreq->sr_timeout_per_command = 10 * HZ;
1442         sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
1443
1444         scsi_insert_special_req(sreq, 1);
1445 }
1446
1447
1448 /**
1449  * scsi_restart_operations - restart io operations to the specified host.
1450  * @shost:      Host we are restarting.
1451  *
1452  * Notes:
1453  *    When we entered the error handler, we blocked all further i/o to
1454  *    this device.  we need to 'reverse' this process.
1455  **/
1456 static void scsi_restart_operations(struct Scsi_Host *shost)
1457 {
1458         struct scsi_device *sdev;
1459
1460         /*
1461          * If the door was locked, we need to insert a door lock request
1462          * onto the head of the SCSI request queue for the device.  There
1463          * is no point trying to lock the door of an off-line device.
1464          */
1465         shost_for_each_device(sdev, shost) {
1466                 if (scsi_device_online(sdev) && sdev->locked)
1467                         scsi_eh_lock_door(sdev);
1468         }
1469
1470         /*
1471          * next free up anything directly waiting upon the host.  this
1472          * will be requests for character device operations, and also for
1473          * ioctls to queued block devices.
1474          */
1475         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1476                                           __FUNCTION__));
1477
1478         clear_bit(SHOST_RECOVERY, &shost->shost_state);
1479
1480         wake_up(&shost->host_wait);
1481
1482         /*
1483          * finally we need to re-initiate requests that may be pending.  we will
1484          * have had everything blocked while error handling is taking place, and
1485          * now that error recovery is done, we will need to ensure that these
1486          * requests are started.
1487          */
1488         scsi_run_host_queues(shost);
1489 }
1490
1491 /**
1492  * scsi_eh_ready_devs - check device ready state and recover if not.
1493  * @shost:      host to be recovered.
1494  * @eh_done_q:  list_head for processed commands.
1495  *
1496  **/
1497 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1498                                struct list_head *work_q,
1499                                struct list_head *done_q)
1500 {
1501         if (!scsi_eh_stu(shost, work_q, done_q))
1502                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1503                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1504                                 if (!scsi_eh_host_reset(work_q, done_q))
1505                                         scsi_eh_offline_sdevs(work_q, done_q);
1506 }
1507
1508 /**
1509  * scsi_eh_flush_done_q - finish processed commands or retry them.
1510  * @done_q:     list_head of processed commands.
1511  *
1512  **/
1513 static void scsi_eh_flush_done_q(struct list_head *done_q)
1514 {
1515         struct list_head *lh, *lh_sf;
1516         struct scsi_cmnd *scmd;
1517
1518         list_for_each_safe(lh, lh_sf, done_q) {
1519                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1520                 list_del_init(lh);
1521                 if (scsi_device_online(scmd->device) &&
1522                     !blk_noretry_request(scmd->request) &&
1523                     (++scmd->retries < scmd->allowed)) {
1524                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1525                                                           " retry cmd: %p\n",
1526                                                           current->comm,
1527                                                           scmd));
1528                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1529                 } else {
1530                         /*
1531                          * If just we got sense for the device (called
1532                          * scsi_eh_get_sense), scmd->result is already
1533                          * set, do not set DRIVER_TIMEOUT.
1534                          */
1535                         if (!scmd->result)
1536                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1537                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1538                                                         " cmd: %p\n",
1539                                                         current->comm, scmd));
1540                         scsi_finish_command(scmd);
1541                 }
1542         }
1543 }
1544
1545 /**
1546  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1547  * @shost:      Host to unjam.
1548  *
1549  * Notes:
1550  *    When we come in here, we *know* that all commands on the bus have
1551  *    either completed, failed or timed out.  we also know that no further
1552  *    commands are being sent to the host, so things are relatively quiet
1553  *    and we have freedom to fiddle with things as we wish.
1554  *
1555  *    This is only the *default* implementation.  it is possible for
1556  *    individual drivers to supply their own version of this function, and
1557  *    if the maintainer wishes to do this, it is strongly suggested that
1558  *    this function be taken as a template and modified.  this function
1559  *    was designed to correctly handle problems for about 95% of the
1560  *    different cases out there, and it should always provide at least a
1561  *    reasonable amount of error recovery.
1562  *
1563  *    Any command marked 'failed' or 'timeout' must eventually have
1564  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1565  *    here, so when we restart the host after we return it should have an
1566  *    empty queue.
1567  **/
1568 static void scsi_unjam_host(struct Scsi_Host *shost)
1569 {
1570         unsigned long flags;
1571         LIST_HEAD(eh_work_q);
1572         LIST_HEAD(eh_done_q);
1573
1574         spin_lock_irqsave(shost->host_lock, flags);
1575         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1576         spin_unlock_irqrestore(shost->host_lock, flags);
1577
1578         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1579
1580         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1581                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1582                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1583
1584         scsi_eh_flush_done_q(&eh_done_q);
1585 }
1586
1587 /**
1588  * scsi_error_handler - Handle errors/timeouts of SCSI cmds.
1589  * @data:       Host for which we are running.
1590  *
1591  * Notes:
1592  *    This is always run in the context of a kernel thread.  The idea is
1593  *    that we start this thing up when the kernel starts up (one per host
1594  *    that we detect), and it immediately goes to sleep and waits for some
1595  *    event (i.e. failure).  When this takes place, we have the job of
1596  *    trying to unjam the bus and restarting things.
1597  **/
1598 int scsi_error_handler(void *data)
1599 {
1600         struct Scsi_Host *shost = (struct Scsi_Host *) data;
1601         int rtn;
1602         DECLARE_MUTEX_LOCKED(sem);
1603
1604         /*
1605          *    Flush resources
1606          */
1607
1608         daemonize("scsi_eh_%d", shost->host_no);
1609
1610         current->flags |= PF_NOFREEZE;
1611
1612         shost->eh_wait = &sem;
1613         shost->ehandler = current;
1614
1615         /*
1616          * Wake up the thread that created us.
1617          */
1618         SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
1619                                           " scsi_eh_%d\n",shost->host_no));
1620
1621         complete(shost->eh_notify);
1622
1623         while (1) {
1624                 /*
1625                  * If we get a signal, it means we are supposed to go
1626                  * away and die.  This typically happens if the user is
1627                  * trying to unload a module.
1628                  */
1629                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1630                                                   " scsi_eh_%d"
1631                                                   " sleeping\n",shost->host_no));
1632
1633                 /*
1634                  * Note - we always use down_interruptible with the semaphore
1635                  * even if the module was loaded as part of the kernel.  The
1636                  * reason is that down() will cause this thread to be counted
1637                  * in the load average as a running process, and down
1638                  * interruptible doesn't.  Given that we need to allow this
1639                  * thread to die if the driver was loaded as a module, using
1640                  * semaphores isn't unreasonable.
1641                  */
1642                 down_interruptible(&sem);
1643                 if (shost->eh_kill)
1644                         break;
1645
1646                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1647                                                   " scsi_eh_%d waking"
1648                                                   " up\n",shost->host_no));
1649
1650                 shost->eh_active = 1;
1651
1652                 /*
1653                  * We have a host that is failing for some reason.  Figure out
1654                  * what we need to do to get it up and online again (if we can).
1655                  * If we fail, we end up taking the thing offline.
1656                  */
1657                 if (shost->hostt->eh_strategy_handler)
1658                         rtn = shost->hostt->eh_strategy_handler(shost);
1659                 else
1660                         scsi_unjam_host(shost);
1661
1662                 shost->eh_active = 0;
1663
1664                 /*
1665                  * Note - if the above fails completely, the action is to take
1666                  * individual devices offline and flush the queue of any
1667                  * outstanding requests that may have been pending.  When we
1668                  * restart, we restart any I/O to any other devices on the bus
1669                  * which are still online.
1670                  */
1671                 scsi_restart_operations(shost);
1672
1673         }
1674
1675         SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
1676                                           " exiting\n",shost->host_no));
1677
1678         /*
1679          * Make sure that nobody tries to wake us up again.
1680          */
1681         shost->eh_wait = NULL;
1682
1683         /*
1684          * Knock this down too.  From this point on, the host is flying
1685          * without a pilot.  If this is because the module is being unloaded,
1686          * that's fine.  If the user sent a signal to this thing, we are
1687          * potentially in real danger.
1688          */
1689         shost->eh_active = 0;
1690         shost->ehandler = NULL;
1691
1692         /*
1693          * If anyone is waiting for us to exit (i.e. someone trying to unload
1694          * a driver), then wake up that process to let them know we are on
1695          * the way out the door.
1696          */
1697         complete_and_exit(shost->eh_notify, 0);
1698         return 0;
1699 }
1700
1701 /*
1702  * Function:    scsi_report_bus_reset()
1703  *
1704  * Purpose:     Utility function used by low-level drivers to report that
1705  *              they have observed a bus reset on the bus being handled.
1706  *
1707  * Arguments:   shost       - Host in question
1708  *              channel     - channel on which reset was observed.
1709  *
1710  * Returns:     Nothing
1711  *
1712  * Lock status: Host lock must be held.
1713  *
1714  * Notes:       This only needs to be called if the reset is one which
1715  *              originates from an unknown location.  Resets originated
1716  *              by the mid-level itself don't need to call this, but there
1717  *              should be no harm.
1718  *
1719  *              The main purpose of this is to make sure that a CHECK_CONDITION
1720  *              is properly treated.
1721  */
1722 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1723 {
1724         struct scsi_device *sdev;
1725
1726         __shost_for_each_device(sdev, shost) {
1727                 if (channel == sdev->channel) {
1728                         sdev->was_reset = 1;
1729                         sdev->expecting_cc_ua = 1;
1730                 }
1731         }
1732 }
1733 EXPORT_SYMBOL(scsi_report_bus_reset);
1734
1735 /*
1736  * Function:    scsi_report_device_reset()
1737  *
1738  * Purpose:     Utility function used by low-level drivers to report that
1739  *              they have observed a device reset on the device being handled.
1740  *
1741  * Arguments:   shost       - Host in question
1742  *              channel     - channel on which reset was observed
1743  *              target      - target on which reset was observed
1744  *
1745  * Returns:     Nothing
1746  *
1747  * Lock status: Host lock must be held
1748  *
1749  * Notes:       This only needs to be called if the reset is one which
1750  *              originates from an unknown location.  Resets originated
1751  *              by the mid-level itself don't need to call this, but there
1752  *              should be no harm.
1753  *
1754  *              The main purpose of this is to make sure that a CHECK_CONDITION
1755  *              is properly treated.
1756  */
1757 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1758 {
1759         struct scsi_device *sdev;
1760
1761         __shost_for_each_device(sdev, shost) {
1762                 if (channel == sdev->channel &&
1763                     target == sdev->id) {
1764                         sdev->was_reset = 1;
1765                         sdev->expecting_cc_ua = 1;
1766                 }
1767         }
1768 }
1769 EXPORT_SYMBOL(scsi_report_device_reset);
1770
1771 static void
1772 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1773 {
1774 }
1775
1776 /*
1777  * Function:    scsi_reset_provider
1778  *
1779  * Purpose:     Send requested reset to a bus or device at any phase.
1780  *
1781  * Arguments:   device  - device to send reset to
1782  *              flag - reset type (see scsi.h)
1783  *
1784  * Returns:     SUCCESS/FAILURE.
1785  *
1786  * Notes:       This is used by the SCSI Generic driver to provide
1787  *              Bus/Device reset capability.
1788  */
1789 int
1790 scsi_reset_provider(struct scsi_device *dev, int flag)
1791 {
1792         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1793         struct request req;
1794         int rtn;
1795
1796         scmd->request = &req;
1797         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1798         scmd->request->rq_status        = RQ_SCSI_BUSY;
1799
1800         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1801
1802         scmd->scsi_done         = scsi_reset_provider_done_command;
1803         scmd->done                      = NULL;
1804         scmd->buffer                    = NULL;
1805         scmd->bufflen                   = 0;
1806         scmd->request_buffer            = NULL;
1807         scmd->request_bufflen           = 0;
1808
1809         scmd->cmd_len                   = 0;
1810
1811         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1812         scmd->sc_request                = NULL;
1813         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1814
1815         init_timer(&scmd->eh_timeout);
1816
1817         /*
1818          * Sometimes the command can get back into the timer chain,
1819          * so use the pid as an identifier.
1820          */
1821         scmd->pid                       = 0;
1822
1823         switch (flag) {
1824         case SCSI_TRY_RESET_DEVICE:
1825                 rtn = scsi_try_bus_device_reset(scmd);
1826                 if (rtn == SUCCESS)
1827                         break;
1828                 /* FALLTHROUGH */
1829         case SCSI_TRY_RESET_BUS:
1830                 rtn = scsi_try_bus_reset(scmd);
1831                 if (rtn == SUCCESS)
1832                         break;
1833                 /* FALLTHROUGH */
1834         case SCSI_TRY_RESET_HOST:
1835                 rtn = scsi_try_host_reset(scmd);
1836                 break;
1837         default:
1838                 rtn = FAILED;
1839         }
1840
1841         scsi_next_command(scmd);
1842         return rtn;
1843 }
1844 EXPORT_SYMBOL(scsi_reset_provider);
1845
1846 /**
1847  * scsi_normalize_sense - normalize main elements from either fixed or
1848  *                      descriptor sense data format into a common format.
1849  *
1850  * @sense_buffer:       byte array containing sense data returned by device
1851  * @sb_len:             number of valid bytes in sense_buffer
1852  * @sshdr:              pointer to instance of structure that common
1853  *                      elements are written to.
1854  *
1855  * Notes:
1856  *      The "main elements" from sense data are: response_code, sense_key,
1857  *      asc, ascq and additional_length (only for descriptor format).
1858  *
1859  *      Typically this function can be called after a device has
1860  *      responded to a SCSI command with the CHECK_CONDITION status.
1861  *
1862  * Return value:
1863  *      1 if valid sense data information found, else 0;
1864  **/
1865 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1866                          struct scsi_sense_hdr *sshdr)
1867 {
1868         if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
1869                 return 0;
1870
1871         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1872
1873         sshdr->response_code = (sense_buffer[0] & 0x7f);
1874         if (sshdr->response_code >= 0x72) {
1875                 /*
1876                  * descriptor format
1877                  */
1878                 if (sb_len > 1)
1879                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1880                 if (sb_len > 2)
1881                         sshdr->asc = sense_buffer[2];
1882                 if (sb_len > 3)
1883                         sshdr->ascq = sense_buffer[3];
1884                 if (sb_len > 7)
1885                         sshdr->additional_length = sense_buffer[7];
1886         } else {
1887                 /*
1888                  * fixed format
1889                  */
1890                 if (sb_len > 2)
1891                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1892                 if (sb_len > 7) {
1893                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1894                                          sb_len : (sense_buffer[7] + 8);
1895                         if (sb_len > 12)
1896                                 sshdr->asc = sense_buffer[12];
1897                         if (sb_len > 13)
1898                                 sshdr->ascq = sense_buffer[13];
1899                 }
1900         }
1901
1902         return 1;
1903 }
1904 EXPORT_SYMBOL(scsi_normalize_sense);
1905
1906 int scsi_request_normalize_sense(struct scsi_request *sreq,
1907                                  struct scsi_sense_hdr *sshdr)
1908 {
1909         return scsi_normalize_sense(sreq->sr_sense_buffer,
1910                         sizeof(sreq->sr_sense_buffer), sshdr);
1911 }
1912 EXPORT_SYMBOL(scsi_request_normalize_sense);
1913
1914 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1915                                  struct scsi_sense_hdr *sshdr)
1916 {
1917         return scsi_normalize_sense(cmd->sense_buffer,
1918                         sizeof(cmd->sense_buffer), sshdr);
1919 }
1920 EXPORT_SYMBOL(scsi_command_normalize_sense);
1921
1922 /**
1923  * scsi_sense_desc_find - search for a given descriptor type in
1924  *                      descriptor sense data format.
1925  *
1926  * @sense_buffer:       byte array of descriptor format sense data
1927  * @sb_len:             number of valid bytes in sense_buffer
1928  * @desc_type:          value of descriptor type to find
1929  *                      (e.g. 0 -> information)
1930  *
1931  * Notes:
1932  *      only valid when sense data is in descriptor format
1933  *
1934  * Return value:
1935  *      pointer to start of (first) descriptor if found else NULL
1936  **/
1937 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1938                                 int desc_type)
1939 {
1940         int add_sen_len, add_len, desc_len, k;
1941         const u8 * descp;
1942
1943         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1944                 return NULL;
1945         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1946                 return NULL;
1947         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1948                         add_sen_len : (sb_len - 8);
1949         descp = &sense_buffer[8];
1950         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1951                 descp += desc_len;
1952                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1953                 desc_len = add_len + 2;
1954                 if (descp[0] == desc_type)
1955                         return descp;
1956                 if (add_len < 0) // short descriptor ??
1957                         break;
1958         }
1959         return NULL;
1960 }
1961 EXPORT_SYMBOL(scsi_sense_desc_find);
1962
1963 /**
1964  * scsi_get_sense_info_fld - attempts to get information field from
1965  *                      sense data (either fixed or descriptor format)
1966  *
1967  * @sense_buffer:       byte array of sense data
1968  * @sb_len:             number of valid bytes in sense_buffer
1969  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1970  *                      field will be placed if found.
1971  *
1972  * Return value:
1973  *      1 if information field found, 0 if not found.
1974  **/
1975 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1976                             u64 * info_out)
1977 {
1978         int j;
1979         const u8 * ucp;
1980         u64 ull;
1981
1982         if (sb_len < 7)
1983                 return 0;
1984         switch (sense_buffer[0] & 0x7f) {
1985         case 0x70:
1986         case 0x71:
1987                 if (sense_buffer[0] & 0x80) {
1988                         *info_out = (sense_buffer[3] << 24) +
1989                                     (sense_buffer[4] << 16) +
1990                                     (sense_buffer[5] << 8) + sense_buffer[6];
1991                         return 1;
1992                 } else
1993                         return 0;
1994         case 0x72:
1995         case 0x73:
1996                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1997                                            0 /* info desc */);
1998                 if (ucp && (0xa == ucp[1])) {
1999                         ull = 0;
2000                         for (j = 0; j < 8; ++j) {
2001                                 if (j > 0)
2002                                         ull <<= 8;
2003                                 ull |= ucp[4 + j];
2004                         }
2005                         *info_out = ull;
2006                         return 1;
2007                 } else
2008                         return 0;
2009         default:
2010                 return 0;
2011         }
2012 }
2013 EXPORT_SYMBOL(scsi_get_sense_info_fld);