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