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         scsi_eh_eflags_set(scmd, eh_flag);
  77         /*
  78          * FIXME: Can we stop setting owner and state.
  79          */
  80         scmd->owner = SCSI_OWNER_ERROR_HANDLER;
  81         scmd->state = SCSI_STATE_FAILED;
  82         /*
  83          * Set the serial_number_at_timeout to the current
  84          * serial_number
  85          */
  86         scmd->serial_number_at_timeout = scmd->serial_number;
  87         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
  88         set_bit(SHOST_RECOVERY, &shost->shost_state);
  89         shost->host_failed++;
  90         scsi_eh_wakeup(shost);
  91         spin_unlock_irqrestore(shost->host_lock, flags);
  92         return 1;
  93 }
  94
  95 /**
  96  * scsi_add_timer - Start timeout timer for a single scsi command.
  97  * @scmd:       scsi command that is about to start running.
  98  * @timeout:    amount of time to allow this command to run.
  99  * @complete:   timeout function to call if timer isn't canceled.
 100  *
 101  * Notes:
 102  *    This should be turned into an inline function.  Each scsi command
 103  *    has its own timer, and as it is added to the queue, we set up the
 104  *    timer.  When the command completes, we cancel the timer.
 105  **/
 106 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
 107                     void (*complete)(struct scsi_cmnd *))
 108 {
 109
 110         /*
 111          * If the clock was already running for this command, then
 112          * first delete the timer.  The timer handling code gets rather
 113          * confused if we don't do this.
 114          */
 115         if (scmd->eh_timeout.function)
 116                 del_timer(&scmd->eh_timeout);
 117
 118         scmd->eh_timeout.data = (unsigned long)scmd;
 119         scmd->eh_timeout.expires = jiffies + timeout;
 120         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
 121
 122         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
 123                                           " %d, (%p)\n", __FUNCTION__,
 124                                           scmd, timeout, complete));
 125
 126         add_timer(&scmd->eh_timeout);
 127 }
 128 EXPORT_SYMBOL(scsi_add_timer);
 129
 130 /**
 131  * scsi_delete_timer - Delete/cancel timer for a given function.
 132  * @scmd:       Cmd that we are canceling timer for
 133  *
 134  * Notes:
 135  *     This should be turned into an inline function.
 136  *
 137  * Return value:
 138  *     1 if we were able to detach the timer.  0 if we blew it, and the
 139  *     timer function has already started to run.
 140  **/
 141 int scsi_delete_timer(struct scsi_cmnd *scmd)
 142 {
 143         int rtn;
 144
 145         rtn = del_timer(&scmd->eh_timeout);
 146
 147         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
 148                                          " rtn: %d\n", __FUNCTION__,
 149                                          scmd, rtn));
 150
 151         scmd->eh_timeout.data = (unsigned long)NULL;
 152         scmd->eh_timeout.function = NULL;
 153
 154         return rtn;
 155 }
 156 EXPORT_SYMBOL(scsi_delete_timer);
 157
 158 /**
 159  * scsi_times_out - Timeout function for normal scsi commands.
 160  * @scmd:       Cmd that is timing out.
 161  *
 162  * Notes:
 163  *     We do not need to lock this.  There is the potential for a race
 164  *     only in that the normal completion handling might run, but if the
 165  *     normal completion function determines that the timer has already
 166  *     fired, then it mustn't do anything.
 167  **/
 168 void scsi_times_out(struct scsi_cmnd *scmd)
 169 {
 170         scsi_log_completion(scmd, TIMEOUT_ERROR);
 171
 172         if (scmd->device->host->hostt->eh_timed_out)
 173                 switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
 174                 case EH_HANDLED:
 175                         __scsi_done(scmd);
 176                         return;
 177                 case EH_RESET_TIMER:
 178                         /* This allows a single retry even of a command
 179                          * with allowed == 0 */
 180                         if (scmd->retries++ > scmd->allowed)
 181                                 break;
 182                         scsi_add_timer(scmd, scmd->timeout_per_command,
 183                                        scsi_times_out);
 184                         return;
 185                 case EH_NOT_HANDLED:
 186                         break;
 187                 }
 188
 189         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 190                 panic("Error handler thread not present at %p %p %s %d",
 191                       scmd, scmd->device->host, __FILE__, __LINE__);
 192         }
 193 }
 194
 195 /**
 196  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 197  * @sdev:       Device on which we are performing recovery.
 198  *
 199  * Description:
 200  *     We block until the host is out of error recovery, and then check to
 201  *     see whether the host or the device is offline.
 202  *
 203  * Return value:
 204  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 205  **/
 206 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 207 {
 208         int online;
 209
 210         wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state)));
 211
 212         online = scsi_device_online(sdev);
 213
 214         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
 215                                           online));
 216
 217         return online;
 218 }
 219 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 220
 221 #ifdef CONFIG_SCSI_LOGGING
 222 /**
 223  * scsi_eh_prt_fail_stats - Log info on failures.
 224  * @shost:      scsi host being recovered.
 225  * @work_q:     Queue of scsi cmds to process.
 226  **/
 227 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 228                                           struct list_head *work_q)
 229 {
 230         struct scsi_cmnd *scmd;
 231         struct scsi_device *sdev;
 232         int total_failures = 0;
 233         int cmd_failed = 0;
 234         int cmd_cancel = 0;
 235         int devices_failed = 0;
 236
 237         shost_for_each_device(sdev, shost) {
 238                 list_for_each_entry(scmd, work_q, eh_entry) {
 239                         if (scmd->device == sdev) {
 240                                 ++total_failures;
 241                                 if (scsi_eh_eflags_chk(scmd,
 242                                                        SCSI_EH_CANCEL_CMD))
 243                                         ++cmd_cancel;
 244                                 else
 245                                         ++cmd_failed;
 246                         }
 247                 }
 248
 249                 if (cmd_cancel || cmd_failed) {
 250                         SCSI_LOG_ERROR_RECOVERY(3,
 251                                 printk("%s: %d:%d:%d:%d cmds failed: %d,"
 252                                        " cancel: %d\n",
 253                                        __FUNCTION__, shost->host_no,
 254                                        sdev->channel, sdev->id, sdev->lun,
 255                                        cmd_failed, cmd_cancel));
 256                         cmd_cancel = 0;
 257                         cmd_failed = 0;
 258                         ++devices_failed;
 259                 }
 260         }
 261
 262         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 263                                           " devices require eh work\n",
 264                                   total_failures, devices_failed));
 265 }
 266 #endif
 267
 268 /**
 269  * scsi_check_sense - Examine scsi cmd sense
 270  * @scmd:       Cmd to have sense checked.
 271  *
 272  * Return value:
 273  *      SUCCESS or FAILED or NEEDS_RETRY
 274  *
 275  * Notes:
 276  *      When a deferred error is detected the current command has
 277  *      not been executed and needs retrying.
 278  **/
 279 static int scsi_check_sense(struct scsi_cmnd *scmd)
 280 {
 281         struct scsi_sense_hdr sshdr;
 282
 283         if (! scsi_command_normalize_sense(scmd, &sshdr))
 284                 return FAILED;  /* no valid sense data */
 285
 286         if (scsi_sense_is_deferred(&sshdr))
 287                 return NEEDS_RETRY;
 288
 289         /*
 290          * Previous logic looked for FILEMARK, EOM or ILI which are
 291          * mainly associated with tapes and returned SUCCESS.
 292          */
 293         if (sshdr.response_code == 0x70) {
 294                 /* fixed format */
 295                 if (scmd->sense_buffer[2] & 0xe0)
 296                         return SUCCESS;
 297         } else {
 298                 /*
 299                  * descriptor format: look for "stream commands sense data
 300                  * descriptor" (see SSC-3). Assume single sense data
 301                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 302                  */
 303                 if ((sshdr.additional_length > 3) &&
 304                     (scmd->sense_buffer[8] == 0x4) &&
 305                     (scmd->sense_buffer[11] & 0xe0))
 306                         return SUCCESS;
 307         }
 308
 309         switch (sshdr.sense_key) {
 310         case NO_SENSE:
 311                 return SUCCESS;
 312         case RECOVERED_ERROR:
 313                 return /* soft_error */ SUCCESS;
 314
 315         case ABORTED_COMMAND:
 316                 return NEEDS_RETRY;
 317         case NOT_READY:
 318         case UNIT_ATTENTION:
 319                 /*
 320                  * if we are expecting a cc/ua because of a bus reset that we
 321                  * performed, treat this just as a retry.  otherwise this is
 322                  * information that we should pass up to the upper-level driver
 323                  * so that we can deal with it there.
 324                  */
 325                 if (scmd->device->expecting_cc_ua) {
 326                         scmd->device->expecting_cc_ua = 0;
 327                         return NEEDS_RETRY;
 328                 }
 329                 /*
 330                  * if the device is in the process of becoming ready, we
 331                  * should retry.
 332                  */
 333                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 334                         return NEEDS_RETRY;
 335                 /*
 336                  * if the device is not started, we need to wake
 337                  * the error handler to start the motor
 338                  */
 339                 if (scmd->device->allow_restart &&
 340                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 341                         return FAILED;
 342                 return SUCCESS;
 343
 344                 /* these three are not supported */
 345         case COPY_ABORTED:
 346         case VOLUME_OVERFLOW:
 347         case MISCOMPARE:
 348                 return SUCCESS;
 349
 350         case MEDIUM_ERROR:
 351                 return NEEDS_RETRY;
 352
 353         case HARDWARE_ERROR:
 354                 if (scmd->device->retry_hwerror)
 355                         return NEEDS_RETRY;
 356                 else
 357                         return SUCCESS;
 358
 359         case ILLEGAL_REQUEST:
 360         case BLANK_CHECK:
 361         case DATA_PROTECT:
 362         default:
 363                 return SUCCESS;
 364         }
 365 }
 366
 367 /**
 368  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 369  * @scmd:       SCSI cmd to examine.
 370  *
 371  * Notes:
 372  *    This is *only* called when we are examining the status of commands
 373  *    queued during error recovery.  the main difference here is that we
 374  *    don't allow for the possibility of retries here, and we are a lot
 375  *    more restrictive about what we consider acceptable.
 376  **/
 377 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 378 {
 379         /*
 380          * first check the host byte, to see if there is anything in there
 381          * that would indicate what we need to do.
 382          */
 383         if (host_byte(scmd->result) == DID_RESET) {
 384                 /*
 385                  * rats.  we are already in the error handler, so we now
 386                  * get to try and figure out what to do next.  if the sense
 387                  * is valid, we have a pretty good idea of what to do.
 388                  * if not, we mark it as FAILED.
 389                  */
 390                 return scsi_check_sense(scmd);
 391         }
 392         if (host_byte(scmd->result) != DID_OK)
 393                 return FAILED;
 394
 395         /*
 396          * next, check the message byte.
 397          */
 398         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 399                 return FAILED;
 400
 401         /*
 402          * now, check the status byte to see if this indicates
 403          * anything special.
 404          */
 405         switch (status_byte(scmd->result)) {
 406         case GOOD:
 407         case COMMAND_TERMINATED:
 408                 return SUCCESS;
 409         case CHECK_CONDITION:
 410                 return scsi_check_sense(scmd);
 411         case CONDITION_GOOD:
 412         case INTERMEDIATE_GOOD:
 413         case INTERMEDIATE_C_GOOD:
 414                 /*
 415                  * who knows?  FIXME(eric)
 416                  */
 417                 return SUCCESS;
 418         case BUSY:
 419         case QUEUE_FULL:
 420         case RESERVATION_CONFLICT:
 421         default:
 422                 return FAILED;
 423         }
 424         return FAILED;
 425 }
 426
 427 /**
 428  * scsi_eh_times_out - timeout function for error handling.
 429  * @scmd:       Cmd that is timing out.
 430  *
 431  * Notes:
 432  *    During error handling, the kernel thread will be sleeping waiting
 433  *    for some action to complete on the device.  our only job is to
 434  *    record that it timed out, and to wake up the thread.
 435  **/
 436 static void scsi_eh_times_out(struct scsi_cmnd *scmd)
 437 {
 438         scsi_eh_eflags_set(scmd, SCSI_EH_REC_TIMEOUT);
 439         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
 440                                           scmd));
 441
 442         if (scmd->device->host->eh_action)
 443                 up(scmd->device->host->eh_action);
 444 }
 445
 446 /**
 447  * scsi_eh_done - Completion function for error handling.
 448  * @scmd:       Cmd that is done.
 449  **/
 450 static void scsi_eh_done(struct scsi_cmnd *scmd)
 451 {
 452         /*
 453          * if the timeout handler is already running, then just set the
 454          * flag which says we finished late, and return.  we have no
 455          * way of stopping the timeout handler from running, so we must
 456          * always defer to it.
 457          */
 458         if (del_timer(&scmd->eh_timeout)) {
 459                 scmd->request->rq_status = RQ_SCSI_DONE;
 460                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
 461
 462                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
 463                                            __FUNCTION__, scmd, scmd->result));
 464
 465                 if (scmd->device->host->eh_action)
 466                         up(scmd->device->host->eh_action);
 467         }
 468 }
 469
 470 /**
 471  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
 472  * @scmd:       SCSI Cmd to send.
 473  * @timeout:    Timeout for cmd.
 474  *
 475  * Notes:
 476  *    The initialization of the structures is quite a bit different in
 477  *    this case, and furthermore, there is a different completion handler
 478  *    vs scsi_dispatch_cmd.
 479  * Return value:
 480  *    SUCCESS or FAILED or NEEDS_RETRY
 481  **/
 482 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
 483 {
 484         struct Scsi_Host *host = scmd->device->host;
 485         DECLARE_MUTEX_LOCKED(sem);
 486         unsigned long flags;
 487         int rtn = SUCCESS;
 488
 489         /*
 490          * we will use a queued command if possible, otherwise we will
 491          * emulate the queuing and calling of completion function ourselves.
 492          */
 493         scmd->owner = SCSI_OWNER_LOWLEVEL;
 494
 495         if (scmd->device->scsi_level <= SCSI_2)
 496                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 497                         (scmd->device->lun << 5 & 0xe0);
 498
 499         scsi_add_timer(scmd, timeout, scsi_eh_times_out);
 500
 501         /*
 502          * set up the semaphore so we wait for the command to complete.
 503          */
 504         scmd->device->host->eh_action = &sem;
 505         scmd->request->rq_status = RQ_SCSI_BUSY;
 506
 507         spin_lock_irqsave(scmd->device->host->host_lock, flags);
 508         scsi_log_send(scmd);
 509         host->hostt->queuecommand(scmd, scsi_eh_done);
 510         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 511
 512         down(&sem);
 513         scsi_log_completion(scmd, SUCCESS);
 514
 515         scmd->device->host->eh_action = NULL;
 516
 517         /*
 518          * see if timeout.  if so, tell the host to forget about it.
 519          * in other words, we don't want a callback any more.
 520          */
 521         if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
 522                 scsi_eh_eflags_clr(scmd,  SCSI_EH_REC_TIMEOUT);
 523                 scmd->owner = SCSI_OWNER_LOWLEVEL;
 524
 525                 /*
 526                  * as far as the low level driver is
 527                  * concerned, this command is still active, so
 528                  * we must give the low level driver a chance
 529                  * to abort it. (db)
 530                  *
 531                  * FIXME(eric) - we are not tracking whether we could
 532                  * abort a timed out command or not.  not sure how
 533                  * we should treat them differently anyways.
 534                  */
 535                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 536                 if (scmd->device->host->hostt->eh_abort_handler)
 537                         scmd->device->host->hostt->eh_abort_handler(scmd);
 538                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 539
 540                 scmd->request->rq_status = RQ_SCSI_DONE;
 541                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
 542
 543                 rtn = FAILED;
 544         }
 545
 546         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
 547                                           __FUNCTION__, scmd, rtn));
 548
 549         /*
 550          * now examine the actual status codes to see whether the command
 551          * actually did complete normally.
 552          */
 553         if (rtn == SUCCESS) {
 554                 rtn = scsi_eh_completed_normally(scmd);
 555                 SCSI_LOG_ERROR_RECOVERY(3,
 556                         printk("%s: scsi_eh_completed_normally %x\n",
 557                                __FUNCTION__, rtn));
 558                 switch (rtn) {
 559                 case SUCCESS:
 560                 case NEEDS_RETRY:
 561                 case FAILED:
 562                         break;
 563                 default:
 564                         rtn = FAILED;
 565                         break;
 566                 }
 567         }
 568
 569         return rtn;
 570 }
 571
 572 /**
 573  * scsi_request_sense - Request sense data from a particular target.
 574  * @scmd:       SCSI cmd for request sense.
 575  *
 576  * Notes:
 577  *    Some hosts automatically obtain this information, others require
 578  *    that we obtain it on our own. This function will *not* return until
 579  *    the command either times out, or it completes.
 580  **/
 581 static int scsi_request_sense(struct scsi_cmnd *scmd)
 582 {
 583         static unsigned char generic_sense[6] =
 584         {REQUEST_SENSE, 0, 0, 0, 252, 0};
 585         unsigned char *scsi_result;
 586         int saved_result;
 587         int rtn;
 588
 589         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
 590
 591         scsi_result = kmalloc(252, GFP_ATOMIC | (scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0);
 592
 593
 594         if (unlikely(!scsi_result)) {
 595                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
 596                        __FUNCTION__);
 597                 return FAILED;
 598         }
 599
 600         /*
 601          * zero the sense buffer.  some host adapters automatically always
 602          * request sense, so it is not a good idea that
 603          * scmd->request_buffer and scmd->sense_buffer point to the same
 604          * address (db).  0 is not a valid sense code.
 605          */
 606         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 607         memset(scsi_result, 0, 252);
 608
 609         saved_result = scmd->result;
 610         scmd->request_buffer = scsi_result;
 611         scmd->request_bufflen = 252;
 612         scmd->use_sg = 0;
 613         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 614         scmd->sc_data_direction = DMA_FROM_DEVICE;
 615         scmd->underflow = 0;
 616
 617         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 618
 619         /* last chance to have valid sense data */
 620         if(!SCSI_SENSE_VALID(scmd)) {
 621                 memcpy(scmd->sense_buffer, scmd->request_buffer,
 622                        sizeof(scmd->sense_buffer));
 623         }
 624
 625         kfree(scsi_result);
 626
 627         /*
 628          * when we eventually call scsi_finish, we really wish to complete
 629          * the original request, so let's restore the original data. (db)
 630          */
 631         scsi_setup_cmd_retry(scmd);
 632         scmd->result = saved_result;
 633         return rtn;
 634 }
 635
 636 /**
 637  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 638  * @scmd:       Original SCSI cmd that eh has finished.
 639  * @done_q:     Queue for processed commands.
 640  *
 641  * Notes:
 642  *    We don't want to use the normal command completion while we are are
 643  *    still handling errors - it may cause other commands to be queued,
 644  *    and that would disturb what we are doing.  thus we really want to
 645  *    keep a list of pending commands for final completion, and once we
 646  *    are ready to leave error handling we handle completion for real.
 647  **/
 648 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
 649                                struct list_head *done_q)
 650 {
 651         scmd->device->host->host_failed--;
 652         scmd->state = SCSI_STATE_BHQUEUE;
 653
 654         scsi_eh_eflags_clr_all(scmd);
 655
 656         /*
 657          * set this back so that the upper level can correctly free up
 658          * things.
 659          */
 660         scsi_setup_cmd_retry(scmd);
 661         list_move_tail(&scmd->eh_entry, done_q);
 662 }
 663
 664 /**
 665  * scsi_eh_get_sense - Get device sense data.
 666  * @work_q:     Queue of commands to process.
 667  * @done_q:     Queue of proccessed commands..
 668  *
 669  * Description:
 670  *    See if we need to request sense information.  if so, then get it
 671  *    now, so we have a better idea of what to do.
 672  *
 673  * Notes:
 674  *    This has the unfortunate side effect that if a shost adapter does
 675  *    not automatically request sense information, that we end up shutting
 676  *    it down before we request it.
 677  *
 678  *    All drivers should request sense information internally these days,
 679  *    so for now all I have to say is tough noogies if you end up in here.
 680  *
 681  *    XXX: Long term this code should go away, but that needs an audit of
 682  *         all LLDDs first.
 683  **/
 684 static int scsi_eh_get_sense(struct list_head *work_q,
 685                              struct list_head *done_q)
 686 {
 687         struct list_head *lh, *lh_sf;
 688         struct scsi_cmnd *scmd;
 689         int rtn;
 690
 691         list_for_each_safe(lh, lh_sf, work_q) {
 692                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 693                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
 694                     SCSI_SENSE_VALID(scmd))
 695                         continue;
 696
 697                 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
 698                                                   " for id: %d\n",
 699                                                   current->comm,
 700                                                   scmd->device->id));
 701                 rtn = scsi_request_sense(scmd);
 702                 if (rtn != SUCCESS)
 703                         continue;
 704
 705                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 706                                                   " result %x\n", scmd,
 707                                                   scmd->result));
 708                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 709
 710                 rtn = scsi_decide_disposition(scmd);
 711
 712                 /*
 713                  * if the result was normal, then just pass it along to the
 714                  * upper level.
 715                  */
 716                 if (rtn == SUCCESS)
 717                         /* we don't want this command reissued, just
 718                          * finished with the sense data, so set
 719                          * retries to the max allowed to ensure it
 720                          * won't get reissued */
 721                         scmd->retries = scmd->allowed;
 722                 else if (rtn != NEEDS_RETRY)
 723                         continue;
 724
 725                 scsi_eh_finish_cmd(scmd, done_q);
 726         }
 727
 728         return list_empty(work_q);
 729 }
 730
 731 /**
 732  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 733  * @scmd:       SCSI cmd to abort from Lower Level.
 734  *
 735  * Notes:
 736  *    This function will not return until the user's completion function
 737  *    has been called.  there is no timeout on this operation.  if the
 738  *    author of the low-level driver wishes this operation to be timed,
 739  *    they can provide this facility themselves.  helper functions in
 740  *    scsi_error.c can be supplied to make this easier to do.
 741  **/
 742 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 743 {
 744         unsigned long flags;
 745         int rtn = FAILED;
 746
 747         if (!scmd->device->host->hostt->eh_abort_handler)
 748                 return rtn;
 749
 750         /*
 751          * scsi_done was called just after the command timed out and before
 752          * we had a chance to process it. (db)
 753          */
 754         if (scmd->serial_number == 0)
 755                 return SUCCESS;
 756
 757         scmd->owner = SCSI_OWNER_LOWLEVEL;
 758
 759         spin_lock_irqsave(scmd->device->host->host_lock, flags);
 760         rtn = scmd->device->host->hostt->eh_abort_handler(scmd);
 761         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 762
 763         return rtn;
 764 }
 765
 766 /**
 767  * scsi_eh_tur - Send TUR to device.
 768  * @scmd:       Scsi cmd to send TUR
 769  *
 770  * Return value:
 771  *    0 - Device is ready. 1 - Device NOT ready.
 772  **/
 773 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 774 {
 775         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 776         int retry_cnt = 1, rtn;
 777
 778 retry_tur:
 779         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
 780
 781         /*
 782          * zero the sense buffer.  the scsi spec mandates that any
 783          * untransferred sense data should be interpreted as being zero.
 784          */
 785         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 786
 787         scmd->request_buffer = NULL;
 788         scmd->request_bufflen = 0;
 789         scmd->use_sg = 0;
 790         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 791         scmd->underflow = 0;
 792         scmd->sc_data_direction = DMA_NONE;
 793
 794         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 795
 796         /*
 797          * when we eventually call scsi_finish, we really wish to complete
 798          * the original request, so let's restore the original data. (db)
 799          */
 800         scsi_setup_cmd_retry(scmd);
 801
 802         /*
 803          * hey, we are done.  let's look to see what happened.
 804          */
 805         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 806                 __FUNCTION__, scmd, rtn));
 807         if (rtn == SUCCESS)
 808                 return 0;
 809         else if (rtn == NEEDS_RETRY)
 810                 if (retry_cnt--)
 811                         goto retry_tur;
 812         return 1;
 813 }
 814
 815 /**
 816  * scsi_eh_abort_cmds - abort canceled commands.
 817  * @shost:      scsi host being recovered.
 818  * @eh_done_q:  list_head for processed commands.
 819  *
 820  * Decription:
 821  *    Try and see whether or not it makes sense to try and abort the
 822  *    running command.  this only works out to be the case if we have one
 823  *    command that has timed out.  if the command simply failed, it makes
 824  *    no sense to try and abort the command, since as far as the shost
 825  *    adapter is concerned, it isn't running.
 826  **/
 827 static int scsi_eh_abort_cmds(struct list_head *work_q,
 828                               struct list_head *done_q)
 829 {
 830         struct list_head *lh, *lh_sf;
 831         struct scsi_cmnd *scmd;
 832         int rtn;
 833
 834         list_for_each_safe(lh, lh_sf, work_q) {
 835                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 836                 if (!scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD))
 837                         continue;
 838                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 839                                                   "0x%p\n", current->comm,
 840                                                   scmd));
 841                 rtn = scsi_try_to_abort_cmd(scmd);
 842                 if (rtn == SUCCESS) {
 843                         scsi_eh_eflags_clr(scmd,  SCSI_EH_CANCEL_CMD);
 844                         if (!scsi_device_online(scmd->device) ||
 845                             !scsi_eh_tur(scmd)) {
 846                                 scsi_eh_finish_cmd(scmd, done_q);
 847                         }
 848
 849                 } else
 850                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 851                                                           " cmd failed:"
 852                                                           "0x%p\n",
 853                                                           current->comm,
 854                                                           scmd));
 855         }
 856
 857         return list_empty(work_q);
 858 }
 859
 860 /**
 861  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 862  * @scmd:       SCSI cmd used to send BDR
 863  *
 864  * Notes:
 865  *    There is no timeout for this operation.  if this operation is
 866  *    unreliable for a given host, then the host itself needs to put a
 867  *    timer on it, and set the host back to a consistent state prior to
 868  *    returning.
 869  **/
 870 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 871 {
 872         unsigned long flags;
 873         int rtn = FAILED;
 874
 875         if (!scmd->device->host->hostt->eh_device_reset_handler)
 876                 return rtn;
 877
 878         scmd->owner = SCSI_OWNER_LOWLEVEL;
 879
 880         spin_lock_irqsave(scmd->device->host->host_lock, flags);
 881         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 882         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 883
 884         if (rtn == SUCCESS) {
 885                 scmd->device->was_reset = 1;
 886                 scmd->device->expecting_cc_ua = 1;
 887         }
 888
 889         return rtn;
 890 }
 891
 892 /**
 893  * scsi_eh_try_stu - Send START_UNIT to device.
 894  * @scmd:       Scsi cmd to send START_UNIT
 895  *
 896  * Return value:
 897  *    0 - Device is ready. 1 - Device NOT ready.
 898  **/
 899 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 900 {
 901         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 902         int rtn;
 903
 904         if (!scmd->device->allow_restart)
 905                 return 1;
 906
 907         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
 908
 909         /*
 910          * zero the sense buffer.  the scsi spec mandates that any
 911          * untransferred sense data should be interpreted as being zero.
 912          */
 913         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 914
 915         scmd->request_buffer = NULL;
 916         scmd->request_bufflen = 0;
 917         scmd->use_sg = 0;
 918         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 919         scmd->underflow = 0;
 920         scmd->sc_data_direction = DMA_NONE;
 921
 922         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
 923
 924         /*
 925          * when we eventually call scsi_finish, we really wish to complete
 926          * the original request, so let's restore the original data. (db)
 927          */
 928         scsi_setup_cmd_retry(scmd);
 929
 930         /*
 931          * hey, we are done.  let's look to see what happened.
 932          */
 933         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 934                 __FUNCTION__, scmd, rtn));
 935         if (rtn == SUCCESS)
 936                 return 0;
 937         return 1;
 938 }
 939
 940  /**
 941  * scsi_eh_stu - send START_UNIT if needed
 942  * @shost:      scsi host being recovered.
 943  * @eh_done_q:  list_head for processed commands.
 944  *
 945  * Notes:
 946  *    If commands are failing due to not ready, initializing command required,
 947  *      try revalidating the device, which will end up sending a start unit.
 948  **/
 949 static int scsi_eh_stu(struct Scsi_Host *shost,
 950                               struct list_head *work_q,
 951                               struct list_head *done_q)
 952 {
 953         struct list_head *lh, *lh_sf;
 954         struct scsi_cmnd *scmd, *stu_scmd;
 955         struct scsi_device *sdev;
 956
 957         shost_for_each_device(sdev, shost) {
 958                 stu_scmd = NULL;
 959                 list_for_each_entry(scmd, work_q, eh_entry)
 960                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 961                             scsi_check_sense(scmd) == FAILED ) {
 962                                 stu_scmd = scmd;
 963                                 break;
 964                         }
 965
 966                 if (!stu_scmd)
 967                         continue;
 968
 969                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 970                                                   " 0x%p\n", current->comm, sdev));
 971
 972                 if (!scsi_eh_try_stu(stu_scmd)) {
 973                         if (!scsi_device_online(sdev) ||
 974                             !scsi_eh_tur(stu_scmd)) {
 975                                 list_for_each_safe(lh, lh_sf, work_q) {
 976                                         scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 977                                         if (scmd->device == sdev)
 978                                                 scsi_eh_finish_cmd(scmd, done_q);
 979                                 }
 980                         }
 981                 } else {
 982                         SCSI_LOG_ERROR_RECOVERY(3,
 983                                                 printk("%s: START_UNIT failed to sdev:"
 984                                                        " 0x%p\n", current->comm, sdev));
 985                 }
 986         }
 987
 988         return list_empty(work_q);
 989 }
 990
 991
 992 /**
 993  * scsi_eh_bus_device_reset - send bdr if needed
 994  * @shost:      scsi host being recovered.
 995  * @eh_done_q:  list_head for processed commands.
 996  *
 997  * Notes:
 998  *    Try a bus device reset.  still, look to see whether we have multiple
 999  *    devices that are jammed or not - if we have multiple devices, it
1000  *    makes no sense to try bus_device_reset - we really would need to try
1001  *    a bus_reset instead.
1002  **/
1003 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1004                                     struct list_head *work_q,
1005                                     struct list_head *done_q)
1006 {
1007         struct list_head *lh, *lh_sf;
1008         struct scsi_cmnd *scmd, *bdr_scmd;
1009         struct scsi_device *sdev;
1010         int rtn;
1011
1012         shost_for_each_device(sdev, shost) {
1013                 bdr_scmd = NULL;
1014                 list_for_each_entry(scmd, work_q, eh_entry)
1015                         if (scmd->device == sdev) {
1016                                 bdr_scmd = scmd;
1017                                 break;
1018                         }
1019
1020                 if (!bdr_scmd)
1021                         continue;
1022
1023                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1024                                                   " 0x%p\n", current->comm,
1025                                                   sdev));
1026                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1027                 if (rtn == SUCCESS) {
1028                         if (!scsi_device_online(sdev) ||
1029                             !scsi_eh_tur(bdr_scmd)) {
1030                                 list_for_each_safe(lh, lh_sf,
1031                                                    work_q) {
1032                                         scmd = list_entry(lh, struct
1033                                                           scsi_cmnd,
1034                                                           eh_entry);
1035                                         if (scmd->device == sdev)
1036                                                 scsi_eh_finish_cmd(scmd,
1037                                                                    done_q);
1038                                 }
1039                         }
1040                 } else {
1041                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1042                                                           " failed sdev:"
1043                                                           "0x%p\n",
1044                                                           current->comm,
1045                                                            sdev));
1046                 }
1047         }
1048
1049         return list_empty(work_q);
1050 }
1051
1052 /**
1053  * scsi_try_bus_reset - ask host to perform a bus reset
1054  * @scmd:       SCSI cmd to send bus reset.
1055  **/
1056 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
1057 {
1058         unsigned long flags;
1059         int rtn;
1060
1061         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1062                                           __FUNCTION__));
1063         scmd->owner = SCSI_OWNER_LOWLEVEL;
1064         scmd->serial_number_at_timeout = scmd->serial_number;
1065
1066         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1067                 return FAILED;
1068
1069         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1070         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1071         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1072
1073         if (rtn == SUCCESS) {
1074                 if (!scmd->device->host->hostt->skip_settle_delay)
1075                         ssleep(BUS_RESET_SETTLE_TIME);
1076                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1077                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1078                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1079         }
1080
1081         return rtn;
1082 }
1083
1084 /**
1085  * scsi_try_host_reset - ask host adapter to reset itself
1086  * @scmd:       SCSI cmd to send hsot reset.
1087  **/
1088 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1089 {
1090         unsigned long flags;
1091         int rtn;
1092
1093         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1094                                           __FUNCTION__));
1095         scmd->owner = SCSI_OWNER_LOWLEVEL;
1096         scmd->serial_number_at_timeout = scmd->serial_number;
1097
1098         if (!scmd->device->host->hostt->eh_host_reset_handler)
1099                 return FAILED;
1100
1101         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1102         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1103         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1104
1105         if (rtn == SUCCESS) {
1106                 if (!scmd->device->host->hostt->skip_settle_delay)
1107                         ssleep(HOST_RESET_SETTLE_TIME);
1108                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1109                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1110                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1111         }
1112
1113         return rtn;
1114 }
1115
1116 /**
1117  * scsi_eh_bus_reset - send a bus reset
1118  * @shost:      scsi host being recovered.
1119  * @eh_done_q:  list_head for processed commands.
1120  **/
1121 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1122                              struct list_head *work_q,
1123                              struct list_head *done_q)
1124 {
1125         struct list_head *lh, *lh_sf;
1126         struct scsi_cmnd *scmd;
1127         struct scsi_cmnd *chan_scmd;
1128         unsigned int channel;
1129         int rtn;
1130
1131         /*
1132          * we really want to loop over the various channels, and do this on
1133          * a channel by channel basis.  we should also check to see if any
1134          * of the failed commands are on soft_reset devices, and if so, skip
1135          * the reset.
1136          */
1137
1138         for (channel = 0; channel <= shost->max_channel; channel++) {
1139                 chan_scmd = NULL;
1140                 list_for_each_entry(scmd, work_q, eh_entry) {
1141                         if (channel == scmd->device->channel) {
1142                                 chan_scmd = scmd;
1143                                 break;
1144                                 /*
1145                                  * FIXME add back in some support for
1146                                  * soft_reset devices.
1147                                  */
1148                         }
1149                 }
1150
1151                 if (!chan_scmd)
1152                         continue;
1153                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1154                                                   " %d\n", current->comm,
1155                                                   channel));
1156                 rtn = scsi_try_bus_reset(chan_scmd);
1157                 if (rtn == SUCCESS) {
1158                         list_for_each_safe(lh, lh_sf, work_q) {
1159                                 scmd = list_entry(lh, struct scsi_cmnd,
1160                                                   eh_entry);
1161                                 if (channel == scmd->device->channel)
1162                                         if (!scsi_device_online(scmd->device) ||
1163                                             !scsi_eh_tur(scmd))
1164                                                 scsi_eh_finish_cmd(scmd,
1165                                                                    done_q);
1166                         }
1167                 } else {
1168                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1169                                                           " failed chan: %d\n",
1170                                                           current->comm,
1171                                                           channel));
1172                 }
1173         }
1174         return list_empty(work_q);
1175 }
1176
1177 /**
1178  * scsi_eh_host_reset - send a host reset
1179  * @work_q:     list_head for processed commands.
1180  * @done_q:     list_head for processed commands.
1181  **/
1182 static int scsi_eh_host_reset(struct list_head *work_q,
1183                               struct list_head *done_q)
1184 {
1185         int rtn;
1186         struct list_head *lh, *lh_sf;
1187         struct scsi_cmnd *scmd;
1188
1189         if (!list_empty(work_q)) {
1190                 scmd = list_entry(work_q->next,
1191                                   struct scsi_cmnd, eh_entry);
1192
1193                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1194                                                   , current->comm));
1195
1196                 rtn = scsi_try_host_reset(scmd);
1197                 if (rtn == SUCCESS) {
1198                         list_for_each_safe(lh, lh_sf, work_q) {
1199                                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1200                                 if (!scsi_device_online(scmd->device) ||
1201                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1202                                     !scsi_eh_tur(scmd))
1203                                         scsi_eh_finish_cmd(scmd, done_q);
1204                         }
1205                 } else {
1206                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1207                                                           " failed\n",
1208                                                           current->comm));
1209                 }
1210         }
1211         return list_empty(work_q);
1212 }
1213
1214 /**
1215  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1216  * @work_q:     list_head for processed commands.
1217  * @done_q:     list_head for processed commands.
1218  *
1219  **/
1220 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1221                                   struct list_head *done_q)
1222 {
1223         struct list_head *lh, *lh_sf;
1224         struct scsi_cmnd *scmd;
1225
1226         list_for_each_safe(lh, lh_sf, work_q) {
1227                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1228                 printk(KERN_INFO "scsi: Device offlined - not"
1229                                 " ready after error recovery: host"
1230                                 " %d channel %d id %d lun %d\n",
1231                                 scmd->device->host->host_no,
1232                                 scmd->device->channel,
1233                                 scmd->device->id,
1234                                 scmd->device->lun);
1235                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1236                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD)) {
1237                         /*
1238                          * FIXME: Handle lost cmds.
1239                          */
1240                 }
1241                 scsi_eh_finish_cmd(scmd, done_q);
1242         }
1243         return;
1244 }
1245
1246 /**
1247  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1248  * @scmd:       SCSI cmd to examine.
1249  *
1250  * Notes:
1251  *    This is *only* called when we are examining the status after sending
1252  *    out the actual data command.  any commands that are queued for error
1253  *    recovery (e.g. test_unit_ready) do *not* come through here.
1254  *
1255  *    When this routine returns failed, it means the error handler thread
1256  *    is woken.  In cases where the error code indicates an error that
1257  *    doesn't require the error handler read (i.e. we don't need to
1258  *    abort/reset), this function should return SUCCESS.
1259  **/
1260 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1261 {
1262         int rtn;
1263
1264         /*
1265          * if the device is offline, then we clearly just pass the result back
1266          * up to the top level.
1267          */
1268         if (!scsi_device_online(scmd->device)) {
1269                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1270                                                   " as SUCCESS\n",
1271                                                   __FUNCTION__));
1272                 return SUCCESS;
1273         }
1274
1275         /*
1276          * first check the host byte, to see if there is anything in there
1277          * that would indicate what we need to do.
1278          */
1279         switch (host_byte(scmd->result)) {
1280         case DID_PASSTHROUGH:
1281                 /*
1282                  * no matter what, pass this through to the upper layer.
1283                  * nuke this special code so that it looks like we are saying
1284                  * did_ok.
1285                  */
1286                 scmd->result &= 0xff00ffff;
1287                 return SUCCESS;
1288         case DID_OK:
1289                 /*
1290                  * looks good.  drop through, and check the next byte.
1291                  */
1292                 break;
1293         case DID_NO_CONNECT:
1294         case DID_BAD_TARGET:
1295         case DID_ABORT:
1296                 /*
1297                  * note - this means that we just report the status back
1298                  * to the top level driver, not that we actually think
1299                  * that it indicates SUCCESS.
1300                  */
1301                 return SUCCESS;
1302                 /*
1303                  * when the low level driver returns did_soft_error,
1304                  * it is responsible for keeping an internal retry counter
1305                  * in order to avoid endless loops (db)
1306                  *
1307                  * actually this is a bug in this function here.  we should
1308                  * be mindful of the maximum number of retries specified
1309                  * and not get stuck in a loop.
1310                  */
1311         case DID_SOFT_ERROR:
1312                 goto maybe_retry;
1313         case DID_IMM_RETRY:
1314                 return NEEDS_RETRY;
1315
1316         case DID_ERROR:
1317                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1318                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1319                         /*
1320                          * execute reservation conflict processing code
1321                          * lower down
1322                          */
1323                         break;
1324                 /* fallthrough */
1325
1326         case DID_BUS_BUSY:
1327         case DID_PARITY:
1328                 goto maybe_retry;
1329         case DID_TIME_OUT:
1330                 /*
1331                  * when we scan the bus, we get timeout messages for
1332                  * these commands if there is no device available.
1333                  * other hosts report did_no_connect for the same thing.
1334                  */
1335                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1336                      scmd->cmnd[0] == INQUIRY)) {
1337                         return SUCCESS;
1338                 } else {
1339                         return FAILED;
1340                 }
1341         case DID_RESET:
1342                 return SUCCESS;
1343         default:
1344                 return FAILED;
1345         }
1346
1347         /*
1348          * next, check the message byte.
1349          */
1350         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1351                 return FAILED;
1352
1353         /*
1354          * check the status byte to see if this indicates anything special.
1355          */
1356         switch (status_byte(scmd->result)) {
1357         case QUEUE_FULL:
1358                 /*
1359                  * the case of trying to send too many commands to a
1360                  * tagged queueing device.
1361                  */
1362         case BUSY:
1363                 /*
1364                  * device can't talk to us at the moment.  Should only
1365                  * occur (SAM-3) when the task queue is empty, so will cause
1366                  * the empty queue handling to trigger a stall in the
1367                  * device.
1368                  */
1369                 return ADD_TO_MLQUEUE;
1370         case GOOD:
1371         case COMMAND_TERMINATED:
1372         case TASK_ABORTED:
1373                 return SUCCESS;
1374         case CHECK_CONDITION:
1375                 rtn = scsi_check_sense(scmd);
1376                 if (rtn == NEEDS_RETRY)
1377                         goto maybe_retry;
1378                 /* if rtn == FAILED, we have no sense information;
1379                  * returning FAILED will wake the error handler thread
1380                  * to collect the sense and redo the decide
1381                  * disposition */
1382                 return rtn;
1383         case CONDITION_GOOD:
1384         case INTERMEDIATE_GOOD:
1385         case INTERMEDIATE_C_GOOD:
1386         case ACA_ACTIVE:
1387                 /*
1388                  * who knows?  FIXME(eric)
1389                  */
1390                 return SUCCESS;
1391
1392         case RESERVATION_CONFLICT:
1393                 printk(KERN_INFO "scsi: reservation conflict: host"
1394                                 " %d channel %d id %d lun %d\n",
1395                        scmd->device->host->host_no, scmd->device->channel,
1396                        scmd->device->id, scmd->device->lun);
1397                 return SUCCESS; /* causes immediate i/o error */
1398         default:
1399                 return FAILED;
1400         }
1401         return FAILED;
1402
1403       maybe_retry:
1404
1405         /* we requeue for retry because the error was retryable, and
1406          * the request was not marked fast fail.  Note that above,
1407          * even if the request is marked fast fail, we still requeue
1408          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1409         if ((++scmd->retries) < scmd->allowed
1410             && !blk_noretry_request(scmd->request)) {
1411                 return NEEDS_RETRY;
1412         } else {
1413                 /*
1414                  * no more retries - report this one back to upper level.
1415                  */
1416                 return SUCCESS;
1417         }
1418 }
1419
1420 /**
1421  * scsi_eh_lock_done - done function for eh door lock request
1422  * @scmd:       SCSI command block for the door lock request
1423  *
1424  * Notes:
1425  *      We completed the asynchronous door lock request, and it has either
1426  *      locked the door or failed.  We must free the command structures
1427  *      associated with this request.
1428  **/
1429 static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
1430 {
1431         struct scsi_request *sreq = scmd->sc_request;
1432
1433         scsi_release_request(sreq);
1434 }
1435
1436
1437 /**
1438  * scsi_eh_lock_door - Prevent medium removal for the specified device
1439  * @sdev:       SCSI device to prevent medium removal
1440  *
1441  * Locking:
1442  *      We must be called from process context; scsi_allocate_request()
1443  *      may sleep.
1444  *
1445  * Notes:
1446  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1447  *      head of the devices request queue, and continue.
1448  *
1449  * Bugs:
1450  *      scsi_allocate_request() may sleep waiting for existing requests to
1451  *      be processed.  However, since we haven't kicked off any request
1452  *      processing for this host, this may deadlock.
1453  *
1454  *      If scsi_allocate_request() fails for what ever reason, we
1455  *      completely forget to lock the door.
1456  **/
1457 static void scsi_eh_lock_door(struct scsi_device *sdev)
1458 {
1459         struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
1460
1461         if (unlikely(!sreq)) {
1462                 printk(KERN_ERR "%s: request allocate failed,"
1463                        "prevent media removal cmd not sent\n", __FUNCTION__);
1464                 return;
1465         }
1466
1467         sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1468         sreq->sr_cmnd[1] = 0;
1469         sreq->sr_cmnd[2] = 0;
1470         sreq->sr_cmnd[3] = 0;
1471         sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
1472         sreq->sr_cmnd[5] = 0;
1473         sreq->sr_data_direction = DMA_NONE;
1474         sreq->sr_bufflen = 0;
1475         sreq->sr_buffer = NULL;
1476         sreq->sr_allowed = 5;
1477         sreq->sr_done = scsi_eh_lock_done;
1478         sreq->sr_timeout_per_command = 10 * HZ;
1479         sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
1480
1481         scsi_insert_special_req(sreq, 1);
1482 }
1483
1484
1485 /**
1486  * scsi_restart_operations - restart io operations to the specified host.
1487  * @shost:      Host we are restarting.
1488  *
1489  * Notes:
1490  *    When we entered the error handler, we blocked all further i/o to
1491  *    this device.  we need to 'reverse' this process.
1492  **/
1493 static void scsi_restart_operations(struct Scsi_Host *shost)
1494 {
1495         struct scsi_device *sdev;
1496
1497         /*
1498          * If the door was locked, we need to insert a door lock request
1499          * onto the head of the SCSI request queue for the device.  There
1500          * is no point trying to lock the door of an off-line device.
1501          */
1502         shost_for_each_device(sdev, shost) {
1503                 if (scsi_device_online(sdev) && sdev->locked)
1504                         scsi_eh_lock_door(sdev);
1505         }
1506
1507         /*
1508          * next free up anything directly waiting upon the host.  this
1509          * will be requests for character device operations, and also for
1510          * ioctls to queued block devices.
1511          */
1512         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1513                                           __FUNCTION__));
1514
1515         clear_bit(SHOST_RECOVERY, &shost->shost_state);
1516
1517         wake_up(&shost->host_wait);
1518
1519         /*
1520          * finally we need to re-initiate requests that may be pending.  we will
1521          * have had everything blocked while error handling is taking place, and
1522          * now that error recovery is done, we will need to ensure that these
1523          * requests are started.
1524          */
1525         scsi_run_host_queues(shost);
1526 }
1527
1528 /**
1529  * scsi_eh_ready_devs - check device ready state and recover if not.
1530  * @shost:      host to be recovered.
1531  * @eh_done_q:  list_head for processed commands.
1532  *
1533  **/
1534 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1535                                struct list_head *work_q,
1536                                struct list_head *done_q)
1537 {
1538         if (!scsi_eh_stu(shost, work_q, done_q))
1539                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1540                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1541                                 if (!scsi_eh_host_reset(work_q, done_q))
1542                                         scsi_eh_offline_sdevs(work_q, done_q);
1543 }
1544
1545 /**
1546  * scsi_eh_flush_done_q - finish processed commands or retry them.
1547  * @done_q:     list_head of processed commands.
1548  *
1549  **/
1550 static void scsi_eh_flush_done_q(struct list_head *done_q)
1551 {
1552         struct list_head *lh, *lh_sf;
1553         struct scsi_cmnd *scmd;
1554
1555         list_for_each_safe(lh, lh_sf, done_q) {
1556                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1557                 list_del_init(lh);
1558                 if (scsi_device_online(scmd->device) &&
1559                     !blk_noretry_request(scmd->request) &&
1560                     (++scmd->retries < scmd->allowed)) {
1561                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1562                                                           " retry cmd: %p\n",
1563                                                           current->comm,
1564                                                           scmd));
1565                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1566                 } else {
1567                         if (!scmd->result)
1568                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1569                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1570                                                         " cmd: %p\n",
1571                                                         current->comm, scmd));
1572                         scsi_finish_command(scmd);
1573                 }
1574         }
1575 }
1576
1577 /**
1578  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1579  * @shost:      Host to unjam.
1580  *
1581  * Notes:
1582  *    When we come in here, we *know* that all commands on the bus have
1583  *    either completed, failed or timed out.  we also know that no further
1584  *    commands are being sent to the host, so things are relatively quiet
1585  *    and we have freedom to fiddle with things as we wish.
1586  *
1587  *    This is only the *default* implementation.  it is possible for
1588  *    individual drivers to supply their own version of this function, and
1589  *    if the maintainer wishes to do this, it is strongly suggested that
1590  *    this function be taken as a template and modified.  this function
1591  *    was designed to correctly handle problems for about 95% of the
1592  *    different cases out there, and it should always provide at least a
1593  *    reasonable amount of error recovery.
1594  *
1595  *    Any command marked 'failed' or 'timeout' must eventually have
1596  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1597  *    here, so when we restart the host after we return it should have an
1598  *    empty queue.
1599  **/
1600 static void scsi_unjam_host(struct Scsi_Host *shost)
1601 {
1602         unsigned long flags;
1603         LIST_HEAD(eh_work_q);
1604         LIST_HEAD(eh_done_q);
1605
1606         spin_lock_irqsave(shost->host_lock, flags);
1607         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1608         spin_unlock_irqrestore(shost->host_lock, flags);
1609
1610         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1611
1612         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1613                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1614                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1615
1616         scsi_eh_flush_done_q(&eh_done_q);
1617 }
1618
1619 /**
1620  * scsi_error_handler - Handle errors/timeouts of SCSI cmds.
1621  * @data:       Host for which we are running.
1622  *
1623  * Notes:
1624  *    This is always run in the context of a kernel thread.  The idea is
1625  *    that we start this thing up when the kernel starts up (one per host
1626  *    that we detect), and it immediately goes to sleep and waits for some
1627  *    event (i.e. failure).  When this takes place, we have the job of
1628  *    trying to unjam the bus and restarting things.
1629  **/
1630 int scsi_error_handler(void *data)
1631 {
1632         struct Scsi_Host *shost = (struct Scsi_Host *) data;
1633         int rtn;
1634         DECLARE_MUTEX_LOCKED(sem);
1635
1636         /*
1637          *    Flush resources
1638          */
1639
1640         daemonize("scsi_eh_%d", shost->host_no);
1641
1642         current->flags |= PF_NOFREEZE;
1643
1644         shost->eh_wait = &sem;
1645         shost->ehandler = current;
1646
1647         /*
1648          * Wake up the thread that created us.
1649          */
1650         SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
1651                                           " scsi_eh_%d\n",shost->host_no));
1652
1653         complete(shost->eh_notify);
1654
1655         while (1) {
1656                 /*
1657                  * If we get a signal, it means we are supposed to go
1658                  * away and die.  This typically happens if the user is
1659                  * trying to unload a module.
1660                  */
1661                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1662                                                   " scsi_eh_%d"
1663                                                   " sleeping\n",shost->host_no));
1664
1665                 /*
1666                  * Note - we always use down_interruptible with the semaphore
1667                  * even if the module was loaded as part of the kernel.  The
1668                  * reason is that down() will cause this thread to be counted
1669                  * in the load average as a running process, and down
1670                  * interruptible doesn't.  Given that we need to allow this
1671                  * thread to die if the driver was loaded as a module, using
1672                  * semaphores isn't unreasonable.
1673                  */
1674                 down_interruptible(&sem);
1675                 if (shost->eh_kill)
1676                         break;
1677
1678                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1679                                                   " scsi_eh_%d waking"
1680                                                   " up\n",shost->host_no));
1681
1682                 shost->eh_active = 1;
1683
1684                 /*
1685                  * We have a host that is failing for some reason.  Figure out
1686                  * what we need to do to get it up and online again (if we can).
1687                  * If we fail, we end up taking the thing offline.
1688                  */
1689                 if (shost->hostt->eh_strategy_handler)
1690                         rtn = shost->hostt->eh_strategy_handler(shost);
1691                 else
1692                         scsi_unjam_host(shost);
1693
1694                 shost->eh_active = 0;
1695
1696                 /*
1697                  * Note - if the above fails completely, the action is to take
1698                  * individual devices offline and flush the queue of any
1699                  * outstanding requests that may have been pending.  When we
1700                  * restart, we restart any I/O to any other devices on the bus
1701                  * which are still online.
1702                  */
1703                 scsi_restart_operations(shost);
1704
1705         }
1706
1707         SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
1708                                           " exiting\n",shost->host_no));
1709
1710         /*
1711          * Make sure that nobody tries to wake us up again.
1712          */
1713         shost->eh_wait = NULL;
1714
1715         /*
1716          * Knock this down too.  From this point on, the host is flying
1717          * without a pilot.  If this is because the module is being unloaded,
1718          * that's fine.  If the user sent a signal to this thing, we are
1719          * potentially in real danger.
1720          */
1721         shost->eh_active = 0;
1722         shost->ehandler = NULL;
1723
1724         /*
1725          * If anyone is waiting for us to exit (i.e. someone trying to unload
1726          * a driver), then wake up that process to let them know we are on
1727          * the way out the door.
1728          */
1729         complete_and_exit(shost->eh_notify, 0);
1730         return 0;
1731 }
1732
1733 /*
1734  * Function:    scsi_report_bus_reset()
1735  *
1736  * Purpose:     Utility function used by low-level drivers to report that
1737  *              they have observed a bus reset on the bus being handled.
1738  *
1739  * Arguments:   shost       - Host in question
1740  *              channel     - channel on which reset was observed.
1741  *
1742  * Returns:     Nothing
1743  *
1744  * Lock status: Host lock must be held.
1745  *
1746  * Notes:       This only needs to be called if the reset is one which
1747  *              originates from an unknown location.  Resets originated
1748  *              by the mid-level itself don't need to call this, but there
1749  *              should be no harm.
1750  *
1751  *              The main purpose of this is to make sure that a CHECK_CONDITION
1752  *              is properly treated.
1753  */
1754 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1755 {
1756         struct scsi_device *sdev;
1757
1758         __shost_for_each_device(sdev, shost) {
1759                 if (channel == sdev->channel) {
1760                         sdev->was_reset = 1;
1761                         sdev->expecting_cc_ua = 1;
1762                 }
1763         }
1764 }
1765 EXPORT_SYMBOL(scsi_report_bus_reset);
1766
1767 /*
1768  * Function:    scsi_report_device_reset()
1769  *
1770  * Purpose:     Utility function used by low-level drivers to report that
1771  *              they have observed a device reset on the device being handled.
1772  *
1773  * Arguments:   shost       - Host in question
1774  *              channel     - channel on which reset was observed
1775  *              target      - target on which reset was observed
1776  *
1777  * Returns:     Nothing
1778  *
1779  * Lock status: Host lock must be held
1780  *
1781  * Notes:       This only needs to be called if the reset is one which
1782  *              originates from an unknown location.  Resets originated
1783  *              by the mid-level itself don't need to call this, but there
1784  *              should be no harm.
1785  *
1786  *              The main purpose of this is to make sure that a CHECK_CONDITION
1787  *              is properly treated.
1788  */
1789 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1790 {
1791         struct scsi_device *sdev;
1792
1793         __shost_for_each_device(sdev, shost) {
1794                 if (channel == sdev->channel &&
1795                     target == sdev->id) {
1796                         sdev->was_reset = 1;
1797                         sdev->expecting_cc_ua = 1;
1798                 }
1799         }
1800 }
1801 EXPORT_SYMBOL(scsi_report_device_reset);
1802
1803 static void
1804 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1805 {
1806 }
1807
1808 /*
1809  * Function:    scsi_reset_provider
1810  *
1811  * Purpose:     Send requested reset to a bus or device at any phase.
1812  *
1813  * Arguments:   device  - device to send reset to
1814  *              flag - reset type (see scsi.h)
1815  *
1816  * Returns:     SUCCESS/FAILURE.
1817  *
1818  * Notes:       This is used by the SCSI Generic driver to provide
1819  *              Bus/Device reset capability.
1820  */
1821 int
1822 scsi_reset_provider(struct scsi_device *dev, int flag)
1823 {
1824         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1825         struct request req;
1826         int rtn;
1827
1828         scmd->request = &req;
1829         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1830         scmd->request->rq_status        = RQ_SCSI_BUSY;
1831         scmd->state                     = SCSI_STATE_INITIALIZING;
1832         scmd->owner                     = SCSI_OWNER_MIDLEVEL;
1833
1834         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1835
1836         scmd->scsi_done         = scsi_reset_provider_done_command;
1837         scmd->done                      = NULL;
1838         scmd->buffer                    = NULL;
1839         scmd->bufflen                   = 0;
1840         scmd->request_buffer            = NULL;
1841         scmd->request_bufflen           = 0;
1842         scmd->internal_timeout          = NORMAL_TIMEOUT;
1843         scmd->abort_reason              = DID_ABORT;
1844
1845         scmd->cmd_len                   = 0;
1846
1847         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1848         scmd->sc_request                = NULL;
1849         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1850
1851         init_timer(&scmd->eh_timeout);
1852
1853         /*
1854          * Sometimes the command can get back into the timer chain,
1855          * so use the pid as an identifier.
1856          */
1857         scmd->pid                       = 0;
1858
1859         switch (flag) {
1860         case SCSI_TRY_RESET_DEVICE:
1861                 rtn = scsi_try_bus_device_reset(scmd);
1862                 if (rtn == SUCCESS)
1863                         break;
1864                 /* FALLTHROUGH */
1865         case SCSI_TRY_RESET_BUS:
1866                 rtn = scsi_try_bus_reset(scmd);
1867                 if (rtn == SUCCESS)
1868                         break;
1869                 /* FALLTHROUGH */
1870         case SCSI_TRY_RESET_HOST:
1871                 rtn = scsi_try_host_reset(scmd);
1872                 break;
1873         default:
1874                 rtn = FAILED;
1875         }
1876
1877         scsi_delete_timer(scmd);
1878         scsi_next_command(scmd);
1879         return rtn;
1880 }
1881 EXPORT_SYMBOL(scsi_reset_provider);
1882
1883 /**
1884  * scsi_normalize_sense - normalize main elements from either fixed or
1885  *                      descriptor sense data format into a common format.
1886  *
1887  * @sense_buffer:       byte array containing sense data returned by device
1888  * @sb_len:             number of valid bytes in sense_buffer
1889  * @sshdr:              pointer to instance of structure that common
1890  *                      elements are written to.
1891  *
1892  * Notes:
1893  *      The "main elements" from sense data are: response_code, sense_key,
1894  *      asc, ascq and additional_length (only for descriptor format).
1895  *
1896  *      Typically this function can be called after a device has
1897  *      responded to a SCSI command with the CHECK_CONDITION status.
1898  *
1899  * Return value:
1900  *      1 if valid sense data information found, else 0;
1901  **/
1902 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1903                          struct scsi_sense_hdr *sshdr)
1904 {
1905         if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
1906                 return 0;
1907
1908         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1909
1910         sshdr->response_code = (sense_buffer[0] & 0x7f);
1911         if (sshdr->response_code >= 0x72) {
1912                 /*
1913                  * descriptor format
1914                  */
1915                 if (sb_len > 1)
1916                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1917                 if (sb_len > 2)
1918                         sshdr->asc = sense_buffer[2];
1919                 if (sb_len > 3)
1920                         sshdr->ascq = sense_buffer[3];
1921                 if (sb_len > 7)
1922                         sshdr->additional_length = sense_buffer[7];
1923         } else {
1924                 /*
1925                  * fixed format
1926                  */
1927                 if (sb_len > 2)
1928                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1929                 if (sb_len > 7) {
1930                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1931                                          sb_len : (sense_buffer[7] + 8);
1932                         if (sb_len > 12)
1933                                 sshdr->asc = sense_buffer[12];
1934                         if (sb_len > 13)
1935                                 sshdr->ascq = sense_buffer[13];
1936                 }
1937         }
1938
1939         return 1;
1940 }
1941 EXPORT_SYMBOL(scsi_normalize_sense);
1942
1943 int scsi_request_normalize_sense(struct scsi_request *sreq,
1944                                  struct scsi_sense_hdr *sshdr)
1945 {
1946         return scsi_normalize_sense(sreq->sr_sense_buffer,
1947                         sizeof(sreq->sr_sense_buffer), sshdr);
1948 }
1949 EXPORT_SYMBOL(scsi_request_normalize_sense);
1950
1951 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1952                                  struct scsi_sense_hdr *sshdr)
1953 {
1954         return scsi_normalize_sense(cmd->sense_buffer,
1955                         sizeof(cmd->sense_buffer), sshdr);
1956 }
1957 EXPORT_SYMBOL(scsi_command_normalize_sense);
1958
1959 /**
1960  * scsi_sense_desc_find - search for a given descriptor type in
1961  *                      descriptor sense data format.
1962  *
1963  * @sense_buffer:       byte array of descriptor format sense data
1964  * @sb_len:             number of valid bytes in sense_buffer
1965  * @desc_type:          value of descriptor type to find
1966  *                      (e.g. 0 -> information)
1967  *
1968  * Notes:
1969  *      only valid when sense data is in descriptor format
1970  *
1971  * Return value:
1972  *      pointer to start of (first) descriptor if found else NULL
1973  **/
1974 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1975                                 int desc_type)
1976 {
1977         int add_sen_len, add_len, desc_len, k;
1978         const u8 * descp;
1979
1980         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1981                 return NULL;
1982         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1983                 return NULL;
1984         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1985                         add_sen_len : (sb_len - 8);
1986         descp = &sense_buffer[8];
1987         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1988                 descp += desc_len;
1989                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1990                 desc_len = add_len + 2;
1991                 if (descp[0] == desc_type)
1992                         return descp;
1993                 if (add_len < 0) // short descriptor ??
1994                         break;
1995         }
1996         return NULL;
1997 }
1998 EXPORT_SYMBOL(scsi_sense_desc_find);
1999
2000 /**
2001  * scsi_get_sense_info_fld - attempts to get information field from
2002  *                      sense data (either fixed or descriptor format)
2003  *
2004  * @sense_buffer:       byte array of sense data
2005  * @sb_len:             number of valid bytes in sense_buffer
2006  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2007  *                      field will be placed if found.
2008  *
2009  * Return value:
2010  *      1 if information field found, 0 if not found.
2011  **/
2012 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2013                             u64 * info_out)
2014 {
2015         int j;
2016         const u8 * ucp;
2017         u64 ull;
2018
2019         if (sb_len < 7)
2020                 return 0;
2021         switch (sense_buffer[0] & 0x7f) {
2022         case 0x70:
2023         case 0x71:
2024                 if (sense_buffer[0] & 0x80) {
2025                         *info_out = (sense_buffer[3] << 24) +
2026                                     (sense_buffer[4] << 16) +
2027                                     (sense_buffer[5] << 8) + sense_buffer[6];
2028                         return 1;
2029                 } else
2030                         return 0;
2031         case 0x72:
2032         case 0x73:
2033                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2034                                            0 /* info desc */);
2035                 if (ucp && (0xa == ucp[1])) {
2036                         ull = 0;
2037                         for (j = 0; j < 8; ++j) {
2038                                 if (j > 0)
2039                                         ull <<= 8;
2040                                 ull |= ucp[4 + j];
2041                         }
2042                         *info_out = ull;
2043                         return 1;
2044                 } else
2045                         return 0;
2046         default:
2047                 return 0;
2048         }
2049 }
2050 EXPORT_SYMBOL(scsi_get_sense_info_fld);