git.oblomov.eu Git - linux-2.6/blob - 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/kernel.h>
  22 #include <linux/freezer.h>
  23 #include <linux/kthread.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/delay.h>
  27
  28 #include <scsi/scsi.h>
  29 #include <scsi/scsi_cmnd.h>
  30 #include <scsi/scsi_dbg.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_eh.h>
  33 #include <scsi/scsi_transport.h>
  34 #include <scsi/scsi_host.h>
  35 #include <scsi/scsi_ioctl.h>
  36
  37 #include "scsi_priv.h"
  38 #include "scsi_logging.h"
  39 #include "scsi_transport_api.h"
  40
  41 #define SENSE_TIMEOUT           (10*HZ)
  42
  43 /*
  44  * These should *probably* be handled by the host itself.
  45  * Since it is allowed to sleep, it probably should.
  46  */
  47 #define BUS_RESET_SETTLE_TIME   (10)
  48 #define HOST_RESET_SETTLE_TIME  (10)
  49
  50 /* called with shost->host_lock held */
  51 void scsi_eh_wakeup(struct Scsi_Host *shost)
  52 {
  53         if (shost->host_busy == shost->host_failed) {
  54                 wake_up_process(shost->ehandler);
  55                 SCSI_LOG_ERROR_RECOVERY(5,
  56                                 printk("Waking error handler thread\n"));
  57         }
  58 }
  59
  60 /**
  61  * scsi_schedule_eh - schedule EH for SCSI host
  62  * @shost:      SCSI host to invoke error handling on.
  63  *
  64  * Schedule SCSI EH without scmd.
  65  */
  66 void scsi_schedule_eh(struct Scsi_Host *shost)
  67 {
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(shost->host_lock, flags);
  71
  72         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  73             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  74                 shost->host_eh_scheduled++;
  75                 scsi_eh_wakeup(shost);
  76         }
  77
  78         spin_unlock_irqrestore(shost->host_lock, flags);
  79 }
  80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  81
  82 /**
  83  * scsi_eh_scmd_add - add scsi cmd to error handling.
  84  * @scmd:       scmd to run eh on.
  85  * @eh_flag:    optional SCSI_EH flag.
  86  *
  87  * Return value:
  88  *      0 on failure.
  89  */
  90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  91 {
  92         struct Scsi_Host *shost = scmd->device->host;
  93         unsigned long flags;
  94         int ret = 0;
  95
  96         if (!shost->ehandler)
  97                 return 0;
  98
  99         spin_lock_irqsave(shost->host_lock, flags);
 100         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 101                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 102                         goto out_unlock;
 103
 104         ret = 1;
 105         scmd->eh_eflags |= eh_flag;
 106         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 107         shost->host_failed++;
 108         scsi_eh_wakeup(shost);
 109  out_unlock:
 110         spin_unlock_irqrestore(shost->host_lock, flags);
 111         return ret;
 112 }
 113
 114 /**
 115  * scsi_add_timer - Start timeout timer for a single scsi command.
 116  * @scmd:       scsi command that is about to start running.
 117  * @timeout:    amount of time to allow this command to run.
 118  * @complete:   timeout function to call if timer isn't canceled.
 119  *
 120  * Notes:
 121  *    This should be turned into an inline function.  Each scsi command
 122  *    has its own timer, and as it is added to the queue, we set up the
 123  *    timer.  When the command completes, we cancel the timer.
 124  */
 125 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
 126                     void (*complete)(struct scsi_cmnd *))
 127 {
 128
 129         /*
 130          * If the clock was already running for this command, then
 131          * first delete the timer.  The timer handling code gets rather
 132          * confused if we don't do this.
 133          */
 134         if (scmd->eh_timeout.function)
 135                 del_timer(&scmd->eh_timeout);
 136
 137         scmd->eh_timeout.data = (unsigned long)scmd;
 138         scmd->eh_timeout.expires = jiffies + timeout;
 139         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
 140
 141         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
 142                                           " %d, (%p)\n", __FUNCTION__,
 143                                           scmd, timeout, complete));
 144
 145         add_timer(&scmd->eh_timeout);
 146 }
 147
 148 /**
 149  * scsi_delete_timer - Delete/cancel timer for a given function.
 150  * @scmd:       Cmd that we are canceling timer for
 151  *
 152  * Notes:
 153  *     This should be turned into an inline function.
 154  *
 155  * Return value:
 156  *     1 if we were able to detach the timer.  0 if we blew it, and the
 157  *     timer function has already started to run.
 158  */
 159 int scsi_delete_timer(struct scsi_cmnd *scmd)
 160 {
 161         int rtn;
 162
 163         rtn = del_timer(&scmd->eh_timeout);
 164
 165         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
 166                                          " rtn: %d\n", __FUNCTION__,
 167                                          scmd, rtn));
 168
 169         scmd->eh_timeout.data = (unsigned long)NULL;
 170         scmd->eh_timeout.function = NULL;
 171
 172         return rtn;
 173 }
 174
 175 /**
 176  * scsi_times_out - Timeout function for normal scsi commands.
 177  * @scmd:       Cmd that is timing out.
 178  *
 179  * Notes:
 180  *     We do not need to lock this.  There is the potential for a race
 181  *     only in that the normal completion handling might run, but if the
 182  *     normal completion function determines that the timer has already
 183  *     fired, then it mustn't do anything.
 184  */
 185 void scsi_times_out(struct scsi_cmnd *scmd)
 186 {
 187         enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
 188
 189         scsi_log_completion(scmd, TIMEOUT_ERROR);
 190
 191         if (scmd->device->host->transportt->eh_timed_out)
 192                 eh_timed_out = scmd->device->host->transportt->eh_timed_out;
 193         else if (scmd->device->host->hostt->eh_timed_out)
 194                 eh_timed_out = scmd->device->host->hostt->eh_timed_out;
 195         else
 196                 eh_timed_out = NULL;
 197
 198         if (eh_timed_out)
 199                 switch (eh_timed_out(scmd)) {
 200                 case EH_HANDLED:
 201                         __scsi_done(scmd);
 202                         return;
 203                 case EH_RESET_TIMER:
 204                         scsi_add_timer(scmd, scmd->timeout_per_command,
 205                                        scsi_times_out);
 206                         return;
 207                 case EH_NOT_HANDLED:
 208                         break;
 209                 }
 210
 211         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 212                 scmd->result |= DID_TIME_OUT << 16;
 213                 __scsi_done(scmd);
 214         }
 215 }
 216
 217 /**
 218  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 219  * @sdev:       Device on which we are performing recovery.
 220  *
 221  * Description:
 222  *     We block until the host is out of error recovery, and then check to
 223  *     see whether the host or the device is offline.
 224  *
 225  * Return value:
 226  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 227  */
 228 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 229 {
 230         int online;
 231
 232         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 233
 234         online = scsi_device_online(sdev);
 235
 236         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
 237                                           online));
 238
 239         return online;
 240 }
 241 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 242
 243 #ifdef CONFIG_SCSI_LOGGING
 244 /**
 245  * scsi_eh_prt_fail_stats - Log info on failures.
 246  * @shost:      scsi host being recovered.
 247  * @work_q:     Queue of scsi cmds to process.
 248  */
 249 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 250                                           struct list_head *work_q)
 251 {
 252         struct scsi_cmnd *scmd;
 253         struct scsi_device *sdev;
 254         int total_failures = 0;
 255         int cmd_failed = 0;
 256         int cmd_cancel = 0;
 257         int devices_failed = 0;
 258
 259         shost_for_each_device(sdev, shost) {
 260                 list_for_each_entry(scmd, work_q, eh_entry) {
 261                         if (scmd->device == sdev) {
 262                                 ++total_failures;
 263                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 264                                         ++cmd_cancel;
 265                                 else
 266                                         ++cmd_failed;
 267                         }
 268                 }
 269
 270                 if (cmd_cancel || cmd_failed) {
 271                         SCSI_LOG_ERROR_RECOVERY(3,
 272                                 sdev_printk(KERN_INFO, sdev,
 273                                             "%s: cmds failed: %d, cancel: %d\n",
 274                                             __FUNCTION__, cmd_failed,
 275                                             cmd_cancel));
 276                         cmd_cancel = 0;
 277                         cmd_failed = 0;
 278                         ++devices_failed;
 279                 }
 280         }
 281
 282         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 283                                           " devices require eh work\n",
 284                                   total_failures, devices_failed));
 285 }
 286 #endif
 287
 288 /**
 289  * scsi_check_sense - Examine scsi cmd sense
 290  * @scmd:       Cmd to have sense checked.
 291  *
 292  * Return value:
 293  *      SUCCESS or FAILED or NEEDS_RETRY
 294  *
 295  * Notes:
 296  *      When a deferred error is detected the current command has
 297  *      not been executed and needs retrying.
 298  */
 299 static int scsi_check_sense(struct scsi_cmnd *scmd)
 300 {
 301         struct scsi_sense_hdr sshdr;
 302
 303         if (! scsi_command_normalize_sense(scmd, &sshdr))
 304                 return FAILED;  /* no valid sense data */
 305
 306         if (scsi_sense_is_deferred(&sshdr))
 307                 return NEEDS_RETRY;
 308
 309         /*
 310          * Previous logic looked for FILEMARK, EOM or ILI which are
 311          * mainly associated with tapes and returned SUCCESS.
 312          */
 313         if (sshdr.response_code == 0x70) {
 314                 /* fixed format */
 315                 if (scmd->sense_buffer[2] & 0xe0)
 316                         return SUCCESS;
 317         } else {
 318                 /*
 319                  * descriptor format: look for "stream commands sense data
 320                  * descriptor" (see SSC-3). Assume single sense data
 321                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 322                  */
 323                 if ((sshdr.additional_length > 3) &&
 324                     (scmd->sense_buffer[8] == 0x4) &&
 325                     (scmd->sense_buffer[11] & 0xe0))
 326                         return SUCCESS;
 327         }
 328
 329         switch (sshdr.sense_key) {
 330         case NO_SENSE:
 331                 return SUCCESS;
 332         case RECOVERED_ERROR:
 333                 return /* soft_error */ SUCCESS;
 334
 335         case ABORTED_COMMAND:
 336                 return NEEDS_RETRY;
 337         case NOT_READY:
 338         case UNIT_ATTENTION:
 339                 /*
 340                  * if we are expecting a cc/ua because of a bus reset that we
 341                  * performed, treat this just as a retry.  otherwise this is
 342                  * information that we should pass up to the upper-level driver
 343                  * so that we can deal with it there.
 344                  */
 345                 if (scmd->device->expecting_cc_ua) {
 346                         scmd->device->expecting_cc_ua = 0;
 347                         return NEEDS_RETRY;
 348                 }
 349                 /*
 350                  * if the device is in the process of becoming ready, we
 351                  * should retry.
 352                  */
 353                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 354                         return NEEDS_RETRY;
 355                 /*
 356                  * if the device is not started, we need to wake
 357                  * the error handler to start the motor
 358                  */
 359                 if (scmd->device->allow_restart &&
 360                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 361                         return FAILED;
 362                 return SUCCESS;
 363
 364                 /* these three are not supported */
 365         case COPY_ABORTED:
 366         case VOLUME_OVERFLOW:
 367         case MISCOMPARE:
 368                 return SUCCESS;
 369
 370         case MEDIUM_ERROR:
 371                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 372                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 373                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 374                         return SUCCESS;
 375                 }
 376                 return NEEDS_RETRY;
 377
 378         case HARDWARE_ERROR:
 379                 if (scmd->device->retry_hwerror)
 380                         return NEEDS_RETRY;
 381                 else
 382                         return SUCCESS;
 383
 384         case ILLEGAL_REQUEST:
 385         case BLANK_CHECK:
 386         case DATA_PROTECT:
 387         default:
 388                 return SUCCESS;
 389         }
 390 }
 391
 392 /**
 393  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 394  * @scmd:       SCSI cmd to examine.
 395  *
 396  * Notes:
 397  *    This is *only* called when we are examining the status of commands
 398  *    queued during error recovery.  the main difference here is that we
 399  *    don't allow for the possibility of retries here, and we are a lot
 400  *    more restrictive about what we consider acceptable.
 401  */
 402 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 403 {
 404         /*
 405          * first check the host byte, to see if there is anything in there
 406          * that would indicate what we need to do.
 407          */
 408         if (host_byte(scmd->result) == DID_RESET) {
 409                 /*
 410                  * rats.  we are already in the error handler, so we now
 411                  * get to try and figure out what to do next.  if the sense
 412                  * is valid, we have a pretty good idea of what to do.
 413                  * if not, we mark it as FAILED.
 414                  */
 415                 return scsi_check_sense(scmd);
 416         }
 417         if (host_byte(scmd->result) != DID_OK)
 418                 return FAILED;
 419
 420         /*
 421          * next, check the message byte.
 422          */
 423         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 424                 return FAILED;
 425
 426         /*
 427          * now, check the status byte to see if this indicates
 428          * anything special.
 429          */
 430         switch (status_byte(scmd->result)) {
 431         case GOOD:
 432         case COMMAND_TERMINATED:
 433                 return SUCCESS;
 434         case CHECK_CONDITION:
 435                 return scsi_check_sense(scmd);
 436         case CONDITION_GOOD:
 437         case INTERMEDIATE_GOOD:
 438         case INTERMEDIATE_C_GOOD:
 439                 /*
 440                  * who knows?  FIXME(eric)
 441                  */
 442                 return SUCCESS;
 443         case BUSY:
 444         case QUEUE_FULL:
 445         case RESERVATION_CONFLICT:
 446         default:
 447                 return FAILED;
 448         }
 449         return FAILED;
 450 }
 451
 452 /**
 453  * scsi_eh_done - Completion function for error handling.
 454  * @scmd:       Cmd that is done.
 455  */
 456 static void scsi_eh_done(struct scsi_cmnd *scmd)
 457 {
 458         struct completion     *eh_action;
 459
 460         SCSI_LOG_ERROR_RECOVERY(3,
 461                 printk("%s scmd: %p result: %x\n",
 462                         __FUNCTION__, scmd, scmd->result));
 463
 464         eh_action = scmd->device->host->eh_action;
 465         if (eh_action)
 466                 complete(eh_action);
 467 }
 468
 469 /**
 470  * scsi_try_host_reset - ask host adapter to reset itself
 471  * @scmd:       SCSI cmd to send hsot reset.
 472  */
 473 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 474 {
 475         unsigned long flags;
 476         int rtn;
 477
 478         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
 479                                           __FUNCTION__));
 480
 481         if (!scmd->device->host->hostt->eh_host_reset_handler)
 482                 return FAILED;
 483
 484         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
 485
 486         if (rtn == SUCCESS) {
 487                 if (!scmd->device->host->hostt->skip_settle_delay)
 488                         ssleep(HOST_RESET_SETTLE_TIME);
 489                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 490                 scsi_report_bus_reset(scmd->device->host,
 491                                       scmd_channel(scmd));
 492                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 493         }
 494
 495         return rtn;
 496 }
 497
 498 /**
 499  * scsi_try_bus_reset - ask host to perform a bus reset
 500  * @scmd:       SCSI cmd to send bus reset.
 501  */
 502 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 503 {
 504         unsigned long flags;
 505         int rtn;
 506
 507         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
 508                                           __FUNCTION__));
 509
 510         if (!scmd->device->host->hostt->eh_bus_reset_handler)
 511                 return FAILED;
 512
 513         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
 514
 515         if (rtn == SUCCESS) {
 516                 if (!scmd->device->host->hostt->skip_settle_delay)
 517                         ssleep(BUS_RESET_SETTLE_TIME);
 518                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 519                 scsi_report_bus_reset(scmd->device->host,
 520                                       scmd_channel(scmd));
 521                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 522         }
 523
 524         return rtn;
 525 }
 526
 527 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 528 {
 529         sdev->was_reset = 1;
 530         sdev->expecting_cc_ua = 1;
 531 }
 532
 533 /**
 534  * scsi_try_target_reset - Ask host to perform a target reset
 535  * @scmd:       SCSI cmd used to send a target reset
 536  *
 537  * Notes:
 538  *    There is no timeout for this operation.  if this operation is
 539  *    unreliable for a given host, then the host itself needs to put a
 540  *    timer on it, and set the host back to a consistent state prior to
 541  *    returning.
 542  */
 543 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 544 {
 545         unsigned long flags;
 546         int rtn;
 547
 548         if (!scmd->device->host->hostt->eh_target_reset_handler)
 549                 return FAILED;
 550
 551         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
 552         if (rtn == SUCCESS) {
 553                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 554                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 555                                           __scsi_report_device_reset);
 556                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 557         }
 558
 559         return rtn;
 560 }
 561
 562 /**
 563  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 564  * @scmd:       SCSI cmd used to send BDR
 565  *
 566  * Notes:
 567  *    There is no timeout for this operation.  if this operation is
 568  *    unreliable for a given host, then the host itself needs to put a
 569  *    timer on it, and set the host back to a consistent state prior to
 570  *    returning.
 571  */
 572 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 573 {
 574         int rtn;
 575
 576         if (!scmd->device->host->hostt->eh_device_reset_handler)
 577                 return FAILED;
 578
 579         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 580         if (rtn == SUCCESS)
 581                 __scsi_report_device_reset(scmd->device, NULL);
 582         return rtn;
 583 }
 584
 585 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 586 {
 587         if (!scmd->device->host->hostt->eh_abort_handler)
 588                 return FAILED;
 589
 590         return scmd->device->host->hostt->eh_abort_handler(scmd);
 591 }
 592
 593 /**
 594  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 595  * @scmd:       SCSI cmd to abort from Lower Level.
 596  *
 597  * Notes:
 598  *    This function will not return until the user's completion function
 599  *    has been called.  there is no timeout on this operation.  if the
 600  *    author of the low-level driver wishes this operation to be timed,
 601  *    they can provide this facility themselves.  helper functions in
 602  *    scsi_error.c can be supplied to make this easier to do.
 603  */
 604 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 605 {
 606         /*
 607          * scsi_done was called just after the command timed out and before
 608          * we had a chance to process it. (db)
 609          */
 610         if (scmd->serial_number == 0)
 611                 return SUCCESS;
 612         return __scsi_try_to_abort_cmd(scmd);
 613 }
 614
 615 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 616 {
 617         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
 618                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 619                         if (scsi_try_target_reset(scmd) != SUCCESS)
 620                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 621                                         scsi_try_host_reset(scmd);
 622 }
 623
 624 /**
 625  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
 626  * @scmd:       SCSI command structure to hijack
 627  * @ses:        structure to save restore information
 628  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 629  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 630  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 631  *
 632  * This function is used to save a scsi command information before re-execution
 633  * as part of the error recovery process.  If @sense_bytes is 0 the command
 634  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 635  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 636  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 637  */
 638 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 639                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 640 {
 641         struct scsi_device *sdev = scmd->device;
 642
 643         /*
 644          * We need saved copies of a number of fields - this is because
 645          * error handling may need to overwrite these with different values
 646          * to run different commands, and once error handling is complete,
 647          * we will need to restore these values prior to running the actual
 648          * command.
 649          */
 650         ses->cmd_len = scmd->cmd_len;
 651         ses->cmnd = scmd->cmnd;
 652         ses->data_direction = scmd->sc_data_direction;
 653         ses->sdb = scmd->sdb;
 654         ses->next_rq = scmd->request->next_rq;
 655         ses->result = scmd->result;
 656
 657         scmd->cmnd = ses->eh_cmnd;
 658         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 659         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 660         scmd->request->next_rq = NULL;
 661
 662         if (sense_bytes) {
 663                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 664                                          sense_bytes);
 665                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 666                             scmd->sdb.length);
 667                 scmd->sdb.table.sgl = &ses->sense_sgl;
 668                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 669                 scmd->sdb.table.nents = 1;
 670                 scmd->cmnd[0] = REQUEST_SENSE;
 671                 scmd->cmnd[4] = scmd->sdb.length;
 672                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 673         } else {
 674                 scmd->sc_data_direction = DMA_NONE;
 675                 if (cmnd) {
 676                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 677                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 678                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 679                 }
 680         }
 681
 682         scmd->underflow = 0;
 683
 684         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 685                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 686                         (sdev->lun << 5 & 0xe0);
 687
 688         /*
 689          * Zero the sense buffer.  The scsi spec mandates that any
 690          * untransferred sense data should be interpreted as being zero.
 691          */
 692         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 693 }
 694 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 695
 696 /**
 697  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
 698  * @scmd:       SCSI command structure to restore
 699  * @ses:        saved information from a coresponding call to scsi_prep_eh_cmnd
 700  *
 701  * Undo any damage done by above scsi_prep_eh_cmnd().
 702  */
 703 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 704 {
 705         /*
 706          * Restore original data
 707          */
 708         scmd->cmd_len = ses->cmd_len;
 709         scmd->cmnd = ses->cmnd;
 710         scmd->sc_data_direction = ses->data_direction;
 711         scmd->sdb = ses->sdb;
 712         scmd->request->next_rq = ses->next_rq;
 713         scmd->result = ses->result;
 714 }
 715 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 716
 717 /**
 718  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
 719  * @scmd:       SCSI command structure to hijack
 720  * @cmnd:       CDB to send
 721  * @cmnd_size:  size in bytes of @cmnd
 722  * @timeout:    timeout for this request
 723  * @sense_bytes: size of sense data to copy or 0
 724  *
 725  * This function is used to send a scsi command down to a target device
 726  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 727  *
 728  * Return value:
 729  *    SUCCESS or FAILED or NEEDS_RETRY
 730  */
 731 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 732                              int cmnd_size, int timeout, unsigned sense_bytes)
 733 {
 734         struct scsi_device *sdev = scmd->device;
 735         struct Scsi_Host *shost = sdev->host;
 736         DECLARE_COMPLETION_ONSTACK(done);
 737         unsigned long timeleft;
 738         unsigned long flags;
 739         struct scsi_eh_save ses;
 740         int rtn;
 741
 742         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
 743         shost->eh_action = &done;
 744
 745         spin_lock_irqsave(shost->host_lock, flags);
 746         scsi_log_send(scmd);
 747         shost->hostt->queuecommand(scmd, scsi_eh_done);
 748         spin_unlock_irqrestore(shost->host_lock, flags);
 749
 750         timeleft = wait_for_completion_timeout(&done, timeout);
 751
 752         shost->eh_action = NULL;
 753
 754         scsi_log_completion(scmd, SUCCESS);
 755
 756         SCSI_LOG_ERROR_RECOVERY(3,
 757                 printk("%s: scmd: %p, timeleft: %ld\n",
 758                         __FUNCTION__, scmd, timeleft));
 759
 760         /*
 761          * If there is time left scsi_eh_done got called, and we will
 762          * examine the actual status codes to see whether the command
 763          * actually did complete normally, else tell the host to forget
 764          * about this command.
 765          */
 766         if (timeleft) {
 767                 rtn = scsi_eh_completed_normally(scmd);
 768                 SCSI_LOG_ERROR_RECOVERY(3,
 769                         printk("%s: scsi_eh_completed_normally %x\n",
 770                                __FUNCTION__, rtn));
 771
 772                 switch (rtn) {
 773                 case SUCCESS:
 774                 case NEEDS_RETRY:
 775                 case FAILED:
 776                         break;
 777                 default:
 778                         rtn = FAILED;
 779                         break;
 780                 }
 781         } else {
 782                 scsi_abort_eh_cmnd(scmd);
 783                 rtn = FAILED;
 784         }
 785
 786         scsi_eh_restore_cmnd(scmd, &ses);
 787         return rtn;
 788 }
 789
 790 /**
 791  * scsi_request_sense - Request sense data from a particular target.
 792  * @scmd:       SCSI cmd for request sense.
 793  *
 794  * Notes:
 795  *    Some hosts automatically obtain this information, others require
 796  *    that we obtain it on our own. This function will *not* return until
 797  *    the command either times out, or it completes.
 798  */
 799 static int scsi_request_sense(struct scsi_cmnd *scmd)
 800 {
 801         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 802 }
 803
 804 /**
 805  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 806  * @scmd:       Original SCSI cmd that eh has finished.
 807  * @done_q:     Queue for processed commands.
 808  *
 809  * Notes:
 810  *    We don't want to use the normal command completion while we are are
 811  *    still handling errors - it may cause other commands to be queued,
 812  *    and that would disturb what we are doing.  Thus we really want to
 813  *    keep a list of pending commands for final completion, and once we
 814  *    are ready to leave error handling we handle completion for real.
 815  */
 816 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 817 {
 818         scmd->device->host->host_failed--;
 819         scmd->eh_eflags = 0;
 820         list_move_tail(&scmd->eh_entry, done_q);
 821 }
 822 EXPORT_SYMBOL(scsi_eh_finish_cmd);
 823
 824 /**
 825  * scsi_eh_get_sense - Get device sense data.
 826  * @work_q:     Queue of commands to process.
 827  * @done_q:     Queue of processed commands.
 828  *
 829  * Description:
 830  *    See if we need to request sense information.  if so, then get it
 831  *    now, so we have a better idea of what to do.
 832  *
 833  * Notes:
 834  *    This has the unfortunate side effect that if a shost adapter does
 835  *    not automatically request sense information, we end up shutting
 836  *    it down before we request it.
 837  *
 838  *    All drivers should request sense information internally these days,
 839  *    so for now all I have to say is tough noogies if you end up in here.
 840  *
 841  *    XXX: Long term this code should go away, but that needs an audit of
 842  *         all LLDDs first.
 843  */
 844 int scsi_eh_get_sense(struct list_head *work_q,
 845                       struct list_head *done_q)
 846 {
 847         struct scsi_cmnd *scmd, *next;
 848         int rtn;
 849
 850         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 851                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 852                     SCSI_SENSE_VALID(scmd))
 853                         continue;
 854
 855                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 856                                                   "%s: requesting sense\n",
 857                                                   current->comm));
 858                 rtn = scsi_request_sense(scmd);
 859                 if (rtn != SUCCESS)
 860                         continue;
 861
 862                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 863                                                   " result %x\n", scmd,
 864                                                   scmd->result));
 865                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 866
 867                 rtn = scsi_decide_disposition(scmd);
 868
 869                 /*
 870                  * if the result was normal, then just pass it along to the
 871                  * upper level.
 872                  */
 873                 if (rtn == SUCCESS)
 874                         /* we don't want this command reissued, just
 875                          * finished with the sense data, so set
 876                          * retries to the max allowed to ensure it
 877                          * won't get reissued */
 878                         scmd->retries = scmd->allowed;
 879                 else if (rtn != NEEDS_RETRY)
 880                         continue;
 881
 882                 scsi_eh_finish_cmd(scmd, done_q);
 883         }
 884
 885         return list_empty(work_q);
 886 }
 887 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 888
 889 /**
 890  * scsi_eh_tur - Send TUR to device.
 891  * @scmd:       &scsi_cmnd to send TUR
 892  *
 893  * Return value:
 894  *    0 - Device is ready. 1 - Device NOT ready.
 895  */
 896 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 897 {
 898         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 899         int retry_cnt = 1, rtn;
 900
 901 retry_tur:
 902         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 903
 904         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 905                 __FUNCTION__, scmd, rtn));
 906
 907         switch (rtn) {
 908         case NEEDS_RETRY:
 909                 if (retry_cnt--)
 910                         goto retry_tur;
 911                 /*FALLTHRU*/
 912         case SUCCESS:
 913                 return 0;
 914         default:
 915                 return 1;
 916         }
 917 }
 918
 919 /**
 920  * scsi_eh_abort_cmds - abort pending commands.
 921  * @work_q:     &list_head for pending commands.
 922  * @done_q:     &list_head for processed commands.
 923  *
 924  * Decription:
 925  *    Try and see whether or not it makes sense to try and abort the
 926  *    running command.  This only works out to be the case if we have one
 927  *    command that has timed out.  If the command simply failed, it makes
 928  *    no sense to try and abort the command, since as far as the shost
 929  *    adapter is concerned, it isn't running.
 930  */
 931 static int scsi_eh_abort_cmds(struct list_head *work_q,
 932                               struct list_head *done_q)
 933 {
 934         struct scsi_cmnd *scmd, *next;
 935         int rtn;
 936
 937         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 938                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 939                         continue;
 940                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 941                                                   "0x%p\n", current->comm,
 942                                                   scmd));
 943                 rtn = scsi_try_to_abort_cmd(scmd);
 944                 if (rtn == SUCCESS) {
 945                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 946                         if (!scsi_device_online(scmd->device) ||
 947                             !scsi_eh_tur(scmd)) {
 948                                 scsi_eh_finish_cmd(scmd, done_q);
 949                         }
 950
 951                 } else
 952                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 953                                                           " cmd failed:"
 954                                                           "0x%p\n",
 955                                                           current->comm,
 956                                                           scmd));
 957         }
 958
 959         return list_empty(work_q);
 960 }
 961
 962 /**
 963  * scsi_eh_try_stu - Send START_UNIT to device.
 964  * @scmd:       &scsi_cmnd to send START_UNIT
 965  *
 966  * Return value:
 967  *    0 - Device is ready. 1 - Device NOT ready.
 968  */
 969 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 970 {
 971         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 972
 973         if (scmd->device->allow_restart) {
 974                 int i, rtn = NEEDS_RETRY;
 975
 976                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
 977                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
 978                                                 scmd->device->timeout, 0);
 979
 980                 if (rtn == SUCCESS)
 981                         return 0;
 982         }
 983
 984         return 1;
 985 }
 986
 987  /**
 988  * scsi_eh_stu - send START_UNIT if needed
 989  * @shost:      &scsi host being recovered.
 990  * @work_q:     &list_head for pending commands.
 991  * @done_q:     &list_head for processed commands.
 992  *
 993  * Notes:
 994  *    If commands are failing due to not ready, initializing command required,
 995  *      try revalidating the device, which will end up sending a start unit.
 996  */
 997 static int scsi_eh_stu(struct Scsi_Host *shost,
 998                               struct list_head *work_q,
 999                               struct list_head *done_q)
1000 {
1001         struct scsi_cmnd *scmd, *stu_scmd, *next;
1002         struct scsi_device *sdev;
1003
1004         shost_for_each_device(sdev, shost) {
1005                 stu_scmd = NULL;
1006                 list_for_each_entry(scmd, work_q, eh_entry)
1007                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1008                             scsi_check_sense(scmd) == FAILED ) {
1009                                 stu_scmd = scmd;
1010                                 break;
1011                         }
1012
1013                 if (!stu_scmd)
1014                         continue;
1015
1016                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1017                                                   " 0x%p\n", current->comm, sdev));
1018
1019                 if (!scsi_eh_try_stu(stu_scmd)) {
1020                         if (!scsi_device_online(sdev) ||
1021                             !scsi_eh_tur(stu_scmd)) {
1022                                 list_for_each_entry_safe(scmd, next,
1023                                                           work_q, eh_entry) {
1024                                         if (scmd->device == sdev)
1025                                                 scsi_eh_finish_cmd(scmd, done_q);
1026                                 }
1027                         }
1028                 } else {
1029                         SCSI_LOG_ERROR_RECOVERY(3,
1030                                                 printk("%s: START_UNIT failed to sdev:"
1031                                                        " 0x%p\n", current->comm, sdev));
1032                 }
1033         }
1034
1035         return list_empty(work_q);
1036 }
1037
1038
1039 /**
1040  * scsi_eh_bus_device_reset - send bdr if needed
1041  * @shost:      scsi host being recovered.
1042  * @work_q:     &list_head for pending commands.
1043  * @done_q:     &list_head for processed commands.
1044  *
1045  * Notes:
1046  *    Try a bus device reset.  Still, look to see whether we have multiple
1047  *    devices that are jammed or not - if we have multiple devices, it
1048  *    makes no sense to try bus_device_reset - we really would need to try
1049  *    a bus_reset instead.
1050  */
1051 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1052                                     struct list_head *work_q,
1053                                     struct list_head *done_q)
1054 {
1055         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1056         struct scsi_device *sdev;
1057         int rtn;
1058
1059         shost_for_each_device(sdev, shost) {
1060                 bdr_scmd = NULL;
1061                 list_for_each_entry(scmd, work_q, eh_entry)
1062                         if (scmd->device == sdev) {
1063                                 bdr_scmd = scmd;
1064                                 break;
1065                         }
1066
1067                 if (!bdr_scmd)
1068                         continue;
1069
1070                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1071                                                   " 0x%p\n", current->comm,
1072                                                   sdev));
1073                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1074                 if (rtn == SUCCESS) {
1075                         if (!scsi_device_online(sdev) ||
1076                             !scsi_eh_tur(bdr_scmd)) {
1077                                 list_for_each_entry_safe(scmd, next,
1078                                                          work_q, eh_entry) {
1079                                         if (scmd->device == sdev)
1080                                                 scsi_eh_finish_cmd(scmd,
1081                                                                    done_q);
1082                                 }
1083                         }
1084                 } else {
1085                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1086                                                           " failed sdev:"
1087                                                           "0x%p\n",
1088                                                           current->comm,
1089                                                            sdev));
1090                 }
1091         }
1092
1093         return list_empty(work_q);
1094 }
1095
1096 /**
1097  * scsi_eh_target_reset - send target reset if needed
1098  * @shost:      scsi host being recovered.
1099  * @work_q:     &list_head for pending commands.
1100  * @done_q:     &list_head for processed commands.
1101  *
1102  * Notes:
1103  *    Try a target reset.
1104  */
1105 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1106                                 struct list_head *work_q,
1107                                 struct list_head *done_q)
1108 {
1109         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1110         unsigned int id;
1111         int rtn;
1112
1113         for (id = 0; id <= shost->max_id; id++) {
1114                 tgtr_scmd = NULL;
1115                 list_for_each_entry(scmd, work_q, eh_entry) {
1116                         if (id == scmd_id(scmd)) {
1117                                 tgtr_scmd = scmd;
1118                                 break;
1119                         }
1120                 }
1121                 if (!tgtr_scmd)
1122                         continue;
1123
1124                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1125                                                   "to target %d\n",
1126                                                   current->comm, id));
1127                 rtn = scsi_try_target_reset(tgtr_scmd);
1128                 if (rtn == SUCCESS) {
1129                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1130                                 if (id == scmd_id(scmd))
1131                                         if (!scsi_device_online(scmd->device) ||
1132                                             !scsi_eh_tur(tgtr_scmd))
1133                                                 scsi_eh_finish_cmd(scmd,
1134                                                                    done_q);
1135                         }
1136                 } else
1137                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1138                                                           " failed target: "
1139                                                           "%d\n",
1140                                                           current->comm, id));
1141         }
1142
1143         return list_empty(work_q);
1144 }
1145
1146 /**
1147  * scsi_eh_bus_reset - send a bus reset
1148  * @shost:      &scsi host being recovered.
1149  * @work_q:     &list_head for pending commands.
1150  * @done_q:     &list_head for processed commands.
1151  */
1152 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1153                              struct list_head *work_q,
1154                              struct list_head *done_q)
1155 {
1156         struct scsi_cmnd *scmd, *chan_scmd, *next;
1157         unsigned int channel;
1158         int rtn;
1159
1160         /*
1161          * we really want to loop over the various channels, and do this on
1162          * a channel by channel basis.  we should also check to see if any
1163          * of the failed commands are on soft_reset devices, and if so, skip
1164          * the reset.
1165          */
1166
1167         for (channel = 0; channel <= shost->max_channel; channel++) {
1168                 chan_scmd = NULL;
1169                 list_for_each_entry(scmd, work_q, eh_entry) {
1170                         if (channel == scmd_channel(scmd)) {
1171                                 chan_scmd = scmd;
1172                                 break;
1173                                 /*
1174                                  * FIXME add back in some support for
1175                                  * soft_reset devices.
1176                                  */
1177                         }
1178                 }
1179
1180                 if (!chan_scmd)
1181                         continue;
1182                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1183                                                   " %d\n", current->comm,
1184                                                   channel));
1185                 rtn = scsi_try_bus_reset(chan_scmd);
1186                 if (rtn == SUCCESS) {
1187                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1188                                 if (channel == scmd_channel(scmd))
1189                                         if (!scsi_device_online(scmd->device) ||
1190                                             !scsi_eh_tur(scmd))
1191                                                 scsi_eh_finish_cmd(scmd,
1192                                                                    done_q);
1193                         }
1194                 } else {
1195                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1196                                                           " failed chan: %d\n",
1197                                                           current->comm,
1198                                                           channel));
1199                 }
1200         }
1201         return list_empty(work_q);
1202 }
1203
1204 /**
1205  * scsi_eh_host_reset - send a host reset
1206  * @work_q:     list_head for processed commands.
1207  * @done_q:     list_head for processed commands.
1208  */
1209 static int scsi_eh_host_reset(struct list_head *work_q,
1210                               struct list_head *done_q)
1211 {
1212         struct scsi_cmnd *scmd, *next;
1213         int rtn;
1214
1215         if (!list_empty(work_q)) {
1216                 scmd = list_entry(work_q->next,
1217                                   struct scsi_cmnd, eh_entry);
1218
1219                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1220                                                   , current->comm));
1221
1222                 rtn = scsi_try_host_reset(scmd);
1223                 if (rtn == SUCCESS) {
1224                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1225                                 if (!scsi_device_online(scmd->device) ||
1226                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1227                                     !scsi_eh_tur(scmd))
1228                                         scsi_eh_finish_cmd(scmd, done_q);
1229                         }
1230                 } else {
1231                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1232                                                           " failed\n",
1233                                                           current->comm));
1234                 }
1235         }
1236         return list_empty(work_q);
1237 }
1238
1239 /**
1240  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1241  * @work_q:     list_head for processed commands.
1242  * @done_q:     list_head for processed commands.
1243  */
1244 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1245                                   struct list_head *done_q)
1246 {
1247         struct scsi_cmnd *scmd, *next;
1248
1249         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1250                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1251                             "not ready after error recovery\n");
1252                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1253                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1254                         /*
1255                          * FIXME: Handle lost cmds.
1256                          */
1257                 }
1258                 scsi_eh_finish_cmd(scmd, done_q);
1259         }
1260         return;
1261 }
1262
1263 /**
1264  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1265  * @scmd:       SCSI cmd to examine.
1266  *
1267  * Notes:
1268  *    This is *only* called when we are examining the status after sending
1269  *    out the actual data command.  any commands that are queued for error
1270  *    recovery (e.g. test_unit_ready) do *not* come through here.
1271  *
1272  *    When this routine returns failed, it means the error handler thread
1273  *    is woken.  In cases where the error code indicates an error that
1274  *    doesn't require the error handler read (i.e. we don't need to
1275  *    abort/reset), this function should return SUCCESS.
1276  */
1277 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1278 {
1279         int rtn;
1280
1281         /*
1282          * if the device is offline, then we clearly just pass the result back
1283          * up to the top level.
1284          */
1285         if (!scsi_device_online(scmd->device)) {
1286                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1287                                                   " as SUCCESS\n",
1288                                                   __FUNCTION__));
1289                 return SUCCESS;
1290         }
1291
1292         /*
1293          * first check the host byte, to see if there is anything in there
1294          * that would indicate what we need to do.
1295          */
1296         switch (host_byte(scmd->result)) {
1297         case DID_PASSTHROUGH:
1298                 /*
1299                  * no matter what, pass this through to the upper layer.
1300                  * nuke this special code so that it looks like we are saying
1301                  * did_ok.
1302                  */
1303                 scmd->result &= 0xff00ffff;
1304                 return SUCCESS;
1305         case DID_OK:
1306                 /*
1307                  * looks good.  drop through, and check the next byte.
1308                  */
1309                 break;
1310         case DID_NO_CONNECT:
1311         case DID_BAD_TARGET:
1312         case DID_ABORT:
1313                 /*
1314                  * note - this means that we just report the status back
1315                  * to the top level driver, not that we actually think
1316                  * that it indicates SUCCESS.
1317                  */
1318                 return SUCCESS;
1319                 /*
1320                  * when the low level driver returns did_soft_error,
1321                  * it is responsible for keeping an internal retry counter
1322                  * in order to avoid endless loops (db)
1323                  *
1324                  * actually this is a bug in this function here.  we should
1325                  * be mindful of the maximum number of retries specified
1326                  * and not get stuck in a loop.
1327                  */
1328         case DID_SOFT_ERROR:
1329                 goto maybe_retry;
1330         case DID_IMM_RETRY:
1331                 return NEEDS_RETRY;
1332
1333         case DID_REQUEUE:
1334                 return ADD_TO_MLQUEUE;
1335
1336         case DID_ERROR:
1337                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1338                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1339                         /*
1340                          * execute reservation conflict processing code
1341                          * lower down
1342                          */
1343                         break;
1344                 /* fallthrough */
1345
1346         case DID_BUS_BUSY:
1347         case DID_PARITY:
1348                 goto maybe_retry;
1349         case DID_TIME_OUT:
1350                 /*
1351                  * when we scan the bus, we get timeout messages for
1352                  * these commands if there is no device available.
1353                  * other hosts report did_no_connect for the same thing.
1354                  */
1355                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1356                      scmd->cmnd[0] == INQUIRY)) {
1357                         return SUCCESS;
1358                 } else {
1359                         return FAILED;
1360                 }
1361         case DID_RESET:
1362                 return SUCCESS;
1363         default:
1364                 return FAILED;
1365         }
1366
1367         /*
1368          * next, check the message byte.
1369          */
1370         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1371                 return FAILED;
1372
1373         /*
1374          * check the status byte to see if this indicates anything special.
1375          */
1376         switch (status_byte(scmd->result)) {
1377         case QUEUE_FULL:
1378                 /*
1379                  * the case of trying to send too many commands to a
1380                  * tagged queueing device.
1381                  */
1382         case BUSY:
1383                 /*
1384                  * device can't talk to us at the moment.  Should only
1385                  * occur (SAM-3) when the task queue is empty, so will cause
1386                  * the empty queue handling to trigger a stall in the
1387                  * device.
1388                  */
1389                 return ADD_TO_MLQUEUE;
1390         case GOOD:
1391         case COMMAND_TERMINATED:
1392         case TASK_ABORTED:
1393                 return SUCCESS;
1394         case CHECK_CONDITION:
1395                 rtn = scsi_check_sense(scmd);
1396                 if (rtn == NEEDS_RETRY)
1397                         goto maybe_retry;
1398                 /* if rtn == FAILED, we have no sense information;
1399                  * returning FAILED will wake the error handler thread
1400                  * to collect the sense and redo the decide
1401                  * disposition */
1402                 return rtn;
1403         case CONDITION_GOOD:
1404         case INTERMEDIATE_GOOD:
1405         case INTERMEDIATE_C_GOOD:
1406         case ACA_ACTIVE:
1407                 /*
1408                  * who knows?  FIXME(eric)
1409                  */
1410                 return SUCCESS;
1411
1412         case RESERVATION_CONFLICT:
1413                 sdev_printk(KERN_INFO, scmd->device,
1414                             "reservation conflict\n");
1415                 return SUCCESS; /* causes immediate i/o error */
1416         default:
1417                 return FAILED;
1418         }
1419         return FAILED;
1420
1421       maybe_retry:
1422
1423         /* we requeue for retry because the error was retryable, and
1424          * the request was not marked fast fail.  Note that above,
1425          * even if the request is marked fast fail, we still requeue
1426          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1427         if ((++scmd->retries) <= scmd->allowed
1428             && !blk_noretry_request(scmd->request)) {
1429                 return NEEDS_RETRY;
1430         } else {
1431                 /*
1432                  * no more retries - report this one back to upper level.
1433                  */
1434                 return SUCCESS;
1435         }
1436 }
1437
1438 /**
1439  * scsi_eh_lock_door - Prevent medium removal for the specified device
1440  * @sdev:       SCSI device to prevent medium removal
1441  *
1442  * Locking:
1443  *      We must be called from process context; scsi_allocate_request()
1444  *      may sleep.
1445  *
1446  * Notes:
1447  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1448  *      head of the devices request queue, and continue.
1449  *
1450  * Bugs:
1451  *      scsi_allocate_request() may sleep waiting for existing requests to
1452  *      be processed.  However, since we haven't kicked off any request
1453  *      processing for this host, this may deadlock.
1454  *
1455  *      If scsi_allocate_request() fails for what ever reason, we
1456  *      completely forget to lock the door.
1457  */
1458 static void scsi_eh_lock_door(struct scsi_device *sdev)
1459 {
1460         unsigned char cmnd[MAX_COMMAND_SIZE];
1461
1462         cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1463         cmnd[1] = 0;
1464         cmnd[2] = 0;
1465         cmnd[3] = 0;
1466         cmnd[4] = SCSI_REMOVAL_PREVENT;
1467         cmnd[5] = 0;
1468
1469         scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1470                            5, NULL, NULL, GFP_KERNEL);
1471 }
1472
1473
1474 /**
1475  * scsi_restart_operations - restart io operations to the specified host.
1476  * @shost:      Host we are restarting.
1477  *
1478  * Notes:
1479  *    When we entered the error handler, we blocked all further i/o to
1480  *    this device.  we need to 'reverse' this process.
1481  */
1482 static void scsi_restart_operations(struct Scsi_Host *shost)
1483 {
1484         struct scsi_device *sdev;
1485         unsigned long flags;
1486
1487         /*
1488          * If the door was locked, we need to insert a door lock request
1489          * onto the head of the SCSI request queue for the device.  There
1490          * is no point trying to lock the door of an off-line device.
1491          */
1492         shost_for_each_device(sdev, shost) {
1493                 if (scsi_device_online(sdev) && sdev->locked)
1494                         scsi_eh_lock_door(sdev);
1495         }
1496
1497         /*
1498          * next free up anything directly waiting upon the host.  this
1499          * will be requests for character device operations, and also for
1500          * ioctls to queued block devices.
1501          */
1502         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1503                                           __FUNCTION__));
1504
1505         spin_lock_irqsave(shost->host_lock, flags);
1506         if (scsi_host_set_state(shost, SHOST_RUNNING))
1507                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1508                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1509         spin_unlock_irqrestore(shost->host_lock, flags);
1510
1511         wake_up(&shost->host_wait);
1512
1513         /*
1514          * finally we need to re-initiate requests that may be pending.  we will
1515          * have had everything blocked while error handling is taking place, and
1516          * now that error recovery is done, we will need to ensure that these
1517          * requests are started.
1518          */
1519         scsi_run_host_queues(shost);
1520 }
1521
1522 /**
1523  * scsi_eh_ready_devs - check device ready state and recover if not.
1524  * @shost:      host to be recovered.
1525  * @work_q:     &list_head for pending commands.
1526  * @done_q:     &list_head for processed commands.
1527  */
1528 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1529                         struct list_head *work_q,
1530                         struct list_head *done_q)
1531 {
1532         if (!scsi_eh_stu(shost, work_q, done_q))
1533                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1534                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1535                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1536                                         if (!scsi_eh_host_reset(work_q, done_q))
1537                                                 scsi_eh_offline_sdevs(work_q,
1538                                                                       done_q);
1539 }
1540 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1541
1542 /**
1543  * scsi_eh_flush_done_q - finish processed commands or retry them.
1544  * @done_q:     list_head of processed commands.
1545  */
1546 void scsi_eh_flush_done_q(struct list_head *done_q)
1547 {
1548         struct scsi_cmnd *scmd, *next;
1549
1550         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1551                 list_del_init(&scmd->eh_entry);
1552                 if (scsi_device_online(scmd->device) &&
1553                     !blk_noretry_request(scmd->request) &&
1554                     (++scmd->retries <= scmd->allowed)) {
1555                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1556                                                           " retry cmd: %p\n",
1557                                                           current->comm,
1558                                                           scmd));
1559                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1560                 } else {
1561                         /*
1562                          * If just we got sense for the device (called
1563                          * scsi_eh_get_sense), scmd->result is already
1564                          * set, do not set DRIVER_TIMEOUT.
1565                          */
1566                         if (!scmd->result)
1567                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1568                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1569                                                         " cmd: %p\n",
1570                                                         current->comm, scmd));
1571                         scsi_finish_command(scmd);
1572                 }
1573         }
1574 }
1575 EXPORT_SYMBOL(scsi_eh_flush_done_q);
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 - SCSI error handler thread
1621  * @data:       Host for which we are running.
1622  *
1623  * Notes:
1624  *    This is the main error handling loop.  This is run as a kernel thread
1625  *    for every SCSI host and handles all error handling activity.
1626  */
1627 int scsi_error_handler(void *data)
1628 {
1629         struct Scsi_Host *shost = data;
1630
1631         /*
1632          * We use TASK_INTERRUPTIBLE so that the thread is not
1633          * counted against the load average as a running process.
1634          * We never actually get interrupted because kthread_run
1635          * disables singal delivery for the created thread.
1636          */
1637         set_current_state(TASK_INTERRUPTIBLE);
1638         while (!kthread_should_stop()) {
1639                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1640                     shost->host_failed != shost->host_busy) {
1641                         SCSI_LOG_ERROR_RECOVERY(1,
1642                                 printk("Error handler scsi_eh_%d sleeping\n",
1643                                         shost->host_no));
1644                         schedule();
1645                         set_current_state(TASK_INTERRUPTIBLE);
1646                         continue;
1647                 }
1648
1649                 __set_current_state(TASK_RUNNING);
1650                 SCSI_LOG_ERROR_RECOVERY(1,
1651                         printk("Error handler scsi_eh_%d waking up\n",
1652                                 shost->host_no));
1653
1654                 /*
1655                  * We have a host that is failing for some reason.  Figure out
1656                  * what we need to do to get it up and online again (if we can).
1657                  * If we fail, we end up taking the thing offline.
1658                  */
1659                 if (shost->transportt->eh_strategy_handler)
1660                         shost->transportt->eh_strategy_handler(shost);
1661                 else
1662                         scsi_unjam_host(shost);
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                 set_current_state(TASK_INTERRUPTIBLE);
1673         }
1674         __set_current_state(TASK_RUNNING);
1675
1676         SCSI_LOG_ERROR_RECOVERY(1,
1677                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1678         shost->ehandler = NULL;
1679         return 0;
1680 }
1681
1682 /*
1683  * Function:    scsi_report_bus_reset()
1684  *
1685  * Purpose:     Utility function used by low-level drivers to report that
1686  *              they have observed a bus reset on the bus being handled.
1687  *
1688  * Arguments:   shost       - Host in question
1689  *              channel     - channel on which reset was observed.
1690  *
1691  * Returns:     Nothing
1692  *
1693  * Lock status: Host lock must be held.
1694  *
1695  * Notes:       This only needs to be called if the reset is one which
1696  *              originates from an unknown location.  Resets originated
1697  *              by the mid-level itself don't need to call this, but there
1698  *              should be no harm.
1699  *
1700  *              The main purpose of this is to make sure that a CHECK_CONDITION
1701  *              is properly treated.
1702  */
1703 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1704 {
1705         struct scsi_device *sdev;
1706
1707         __shost_for_each_device(sdev, shost) {
1708                 if (channel == sdev_channel(sdev))
1709                         __scsi_report_device_reset(sdev, NULL);
1710         }
1711 }
1712 EXPORT_SYMBOL(scsi_report_bus_reset);
1713
1714 /*
1715  * Function:    scsi_report_device_reset()
1716  *
1717  * Purpose:     Utility function used by low-level drivers to report that
1718  *              they have observed a device reset on the device being handled.
1719  *
1720  * Arguments:   shost       - Host in question
1721  *              channel     - channel on which reset was observed
1722  *              target      - target on which reset was observed
1723  *
1724  * Returns:     Nothing
1725  *
1726  * Lock status: Host lock must be held
1727  *
1728  * Notes:       This only needs to be called if the reset is one which
1729  *              originates from an unknown location.  Resets originated
1730  *              by the mid-level itself don't need to call this, but there
1731  *              should be no harm.
1732  *
1733  *              The main purpose of this is to make sure that a CHECK_CONDITION
1734  *              is properly treated.
1735  */
1736 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1737 {
1738         struct scsi_device *sdev;
1739
1740         __shost_for_each_device(sdev, shost) {
1741                 if (channel == sdev_channel(sdev) &&
1742                     target == sdev_id(sdev))
1743                         __scsi_report_device_reset(sdev, NULL);
1744         }
1745 }
1746 EXPORT_SYMBOL(scsi_report_device_reset);
1747
1748 static void
1749 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1750 {
1751 }
1752
1753 /*
1754  * Function:    scsi_reset_provider
1755  *
1756  * Purpose:     Send requested reset to a bus or device at any phase.
1757  *
1758  * Arguments:   device  - device to send reset to
1759  *              flag - reset type (see scsi.h)
1760  *
1761  * Returns:     SUCCESS/FAILURE.
1762  *
1763  * Notes:       This is used by the SCSI Generic driver to provide
1764  *              Bus/Device reset capability.
1765  */
1766 int
1767 scsi_reset_provider(struct scsi_device *dev, int flag)
1768 {
1769         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1770         struct Scsi_Host *shost = dev->host;
1771         struct request req;
1772         unsigned long flags;
1773         int rtn;
1774
1775         blk_rq_init(NULL, &req);
1776         scmd->request = &req;
1777         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1778
1779         scmd->cmnd = req.cmd;
1780
1781         scmd->scsi_done         = scsi_reset_provider_done_command;
1782         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1783
1784         scmd->cmd_len                   = 0;
1785
1786         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1787
1788         init_timer(&scmd->eh_timeout);
1789
1790         spin_lock_irqsave(shost->host_lock, flags);
1791         shost->tmf_in_progress = 1;
1792         spin_unlock_irqrestore(shost->host_lock, flags);
1793
1794         switch (flag) {
1795         case SCSI_TRY_RESET_DEVICE:
1796                 rtn = scsi_try_bus_device_reset(scmd);
1797                 if (rtn == SUCCESS)
1798                         break;
1799                 /* FALLTHROUGH */
1800         case SCSI_TRY_RESET_TARGET:
1801                 rtn = scsi_try_target_reset(scmd);
1802                 if (rtn == SUCCESS)
1803                         break;
1804                 /* FALLTHROUGH */
1805         case SCSI_TRY_RESET_BUS:
1806                 rtn = scsi_try_bus_reset(scmd);
1807                 if (rtn == SUCCESS)
1808                         break;
1809                 /* FALLTHROUGH */
1810         case SCSI_TRY_RESET_HOST:
1811                 rtn = scsi_try_host_reset(scmd);
1812                 break;
1813         default:
1814                 rtn = FAILED;
1815         }
1816
1817         spin_lock_irqsave(shost->host_lock, flags);
1818         shost->tmf_in_progress = 0;
1819         spin_unlock_irqrestore(shost->host_lock, flags);
1820
1821         /*
1822          * be sure to wake up anyone who was sleeping or had their queue
1823          * suspended while we performed the TMF.
1824          */
1825         SCSI_LOG_ERROR_RECOVERY(3,
1826                 printk("%s: waking up host to restart after TMF\n",
1827                 __FUNCTION__));
1828
1829         wake_up(&shost->host_wait);
1830
1831         scsi_run_host_queues(shost);
1832
1833         scsi_next_command(scmd);
1834         return rtn;
1835 }
1836 EXPORT_SYMBOL(scsi_reset_provider);
1837
1838 /**
1839  * scsi_normalize_sense - normalize main elements from either fixed or
1840  *                      descriptor sense data format into a common format.
1841  *
1842  * @sense_buffer:       byte array containing sense data returned by device
1843  * @sb_len:             number of valid bytes in sense_buffer
1844  * @sshdr:              pointer to instance of structure that common
1845  *                      elements are written to.
1846  *
1847  * Notes:
1848  *      The "main elements" from sense data are: response_code, sense_key,
1849  *      asc, ascq and additional_length (only for descriptor format).
1850  *
1851  *      Typically this function can be called after a device has
1852  *      responded to a SCSI command with the CHECK_CONDITION status.
1853  *
1854  * Return value:
1855  *      1 if valid sense data information found, else 0;
1856  */
1857 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1858                          struct scsi_sense_hdr *sshdr)
1859 {
1860         if (!sense_buffer || !sb_len)
1861                 return 0;
1862
1863         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1864
1865         sshdr->response_code = (sense_buffer[0] & 0x7f);
1866
1867         if (!scsi_sense_valid(sshdr))
1868                 return 0;
1869
1870         if (sshdr->response_code >= 0x72) {
1871                 /*
1872                  * descriptor format
1873                  */
1874                 if (sb_len > 1)
1875                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1876                 if (sb_len > 2)
1877                         sshdr->asc = sense_buffer[2];
1878                 if (sb_len > 3)
1879                         sshdr->ascq = sense_buffer[3];
1880                 if (sb_len > 7)
1881                         sshdr->additional_length = sense_buffer[7];
1882         } else {
1883                 /*
1884                  * fixed format
1885                  */
1886                 if (sb_len > 2)
1887                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1888                 if (sb_len > 7) {
1889                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1890                                          sb_len : (sense_buffer[7] + 8);
1891                         if (sb_len > 12)
1892                                 sshdr->asc = sense_buffer[12];
1893                         if (sb_len > 13)
1894                                 sshdr->ascq = sense_buffer[13];
1895                 }
1896         }
1897
1898         return 1;
1899 }
1900 EXPORT_SYMBOL(scsi_normalize_sense);
1901
1902 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1903                                  struct scsi_sense_hdr *sshdr)
1904 {
1905         return scsi_normalize_sense(cmd->sense_buffer,
1906                         SCSI_SENSE_BUFFERSIZE, sshdr);
1907 }
1908 EXPORT_SYMBOL(scsi_command_normalize_sense);
1909
1910 /**
1911  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1912  * @sense_buffer:       byte array of descriptor format sense data
1913  * @sb_len:             number of valid bytes in sense_buffer
1914  * @desc_type:          value of descriptor type to find
1915  *                      (e.g. 0 -> information)
1916  *
1917  * Notes:
1918  *      only valid when sense data is in descriptor format
1919  *
1920  * Return value:
1921  *      pointer to start of (first) descriptor if found else NULL
1922  */
1923 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1924                                 int desc_type)
1925 {
1926         int add_sen_len, add_len, desc_len, k;
1927         const u8 * descp;
1928
1929         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1930                 return NULL;
1931         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1932                 return NULL;
1933         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1934                         add_sen_len : (sb_len - 8);
1935         descp = &sense_buffer[8];
1936         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1937                 descp += desc_len;
1938                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1939                 desc_len = add_len + 2;
1940                 if (descp[0] == desc_type)
1941                         return descp;
1942                 if (add_len < 0) // short descriptor ??
1943                         break;
1944         }
1945         return NULL;
1946 }
1947 EXPORT_SYMBOL(scsi_sense_desc_find);
1948
1949 /**
1950  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
1951  * @sense_buffer:       byte array of sense data
1952  * @sb_len:             number of valid bytes in sense_buffer
1953  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1954  *                      field will be placed if found.
1955  *
1956  * Return value:
1957  *      1 if information field found, 0 if not found.
1958  */
1959 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1960                             u64 * info_out)
1961 {
1962         int j;
1963         const u8 * ucp;
1964         u64 ull;
1965
1966         if (sb_len < 7)
1967                 return 0;
1968         switch (sense_buffer[0] & 0x7f) {
1969         case 0x70:
1970         case 0x71:
1971                 if (sense_buffer[0] & 0x80) {
1972                         *info_out = (sense_buffer[3] << 24) +
1973                                     (sense_buffer[4] << 16) +
1974                                     (sense_buffer[5] << 8) + sense_buffer[6];
1975                         return 1;
1976                 } else
1977                         return 0;
1978         case 0x72:
1979         case 0x73:
1980                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1981                                            0 /* info desc */);
1982                 if (ucp && (0xa == ucp[1])) {
1983                         ull = 0;
1984                         for (j = 0; j < 8; ++j) {
1985                                 if (j > 0)
1986                                         ull <<= 8;
1987                                 ull |= ucp[4 + j];
1988                         }
1989                         *info_out = ull;
1990                         return 1;
1991                 } else
1992                         return 0;
1993         default:
1994                 return 0;
1995         }
1996 }
1997 EXPORT_SYMBOL(scsi_get_sense_info_fld);
1998
1999 /**
2000  * scsi_build_sense_buffer - build sense data in a buffer
2001  * @desc:       Sense format (non zero == descriptor format,
2002  *              0 == fixed format)
2003  * @buf:        Where to build sense data
2004  * @key:        Sense key
2005  * @asc:        Additional sense code
2006  * @ascq:       Additional sense code qualifier
2007  *
2008  **/
2009 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2010 {
2011         if (desc) {
2012                 buf[0] = 0x72;  /* descriptor, current */
2013                 buf[1] = key;
2014                 buf[2] = asc;
2015                 buf[3] = ascq;
2016                 buf[7] = 0;
2017         } else {
2018                 buf[0] = 0x70;  /* fixed, current */
2019                 buf[2] = key;
2020                 buf[7] = 0xa;
2021                 buf[12] = asc;
2022                 buf[13] = ascq;
2023         }
2024 }
2025 EXPORT_SYMBOL(scsi_build_sense_buffer);