Merge tag 'ntb-4.6' of git://github.com/jonmason/ntb
[linux-2.6-microblaze.git] / 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/gfp.h>
20 #include <linux/timer.h>
21 #include <linux/string.h>
22 #include <linux/kernel.h>
23 #include <linux/freezer.h>
24 #include <linux/kthread.h>
25 #include <linux/interrupt.h>
26 #include <linux/blkdev.h>
27 #include <linux/delay.h>
28 #include <linux/jiffies.h>
29
30 #include <scsi/scsi.h>
31 #include <scsi/scsi_cmnd.h>
32 #include <scsi/scsi_dbg.h>
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_driver.h>
35 #include <scsi/scsi_eh.h>
36 #include <scsi/scsi_common.h>
37 #include <scsi/scsi_transport.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_ioctl.h>
40 #include <scsi/scsi_dh.h>
41 #include <scsi/sg.h>
42
43 #include "scsi_priv.h"
44 #include "scsi_logging.h"
45 #include "scsi_transport_api.h"
46
47 #include <trace/events/scsi.h>
48
49 static void scsi_eh_done(struct scsi_cmnd *scmd);
50
51 /*
52  * These should *probably* be handled by the host itself.
53  * Since it is allowed to sleep, it probably should.
54  */
55 #define BUS_RESET_SETTLE_TIME   (10)
56 #define HOST_RESET_SETTLE_TIME  (10)
57
58 static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
59 static int scsi_try_to_abort_cmd(struct scsi_host_template *,
60                                  struct scsi_cmnd *);
61
62 /* called with shost->host_lock held */
63 void scsi_eh_wakeup(struct Scsi_Host *shost)
64 {
65         if (atomic_read(&shost->host_busy) == shost->host_failed) {
66                 trace_scsi_eh_wakeup(shost);
67                 wake_up_process(shost->ehandler);
68                 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
69                         "Waking error handler thread\n"));
70         }
71 }
72
73 /**
74  * scsi_schedule_eh - schedule EH for SCSI host
75  * @shost:      SCSI host to invoke error handling on.
76  *
77  * Schedule SCSI EH without scmd.
78  */
79 void scsi_schedule_eh(struct Scsi_Host *shost)
80 {
81         unsigned long flags;
82
83         spin_lock_irqsave(shost->host_lock, flags);
84
85         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
86             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
87                 shost->host_eh_scheduled++;
88                 scsi_eh_wakeup(shost);
89         }
90
91         spin_unlock_irqrestore(shost->host_lock, flags);
92 }
93 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
94
95 static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
96 {
97         if (!shost->last_reset || shost->eh_deadline == -1)
98                 return 0;
99
100         /*
101          * 32bit accesses are guaranteed to be atomic
102          * (on all supported architectures), so instead
103          * of using a spinlock we can as well double check
104          * if eh_deadline has been set to 'off' during the
105          * time_before call.
106          */
107         if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
108             shost->eh_deadline > -1)
109                 return 0;
110
111         return 1;
112 }
113
114 /**
115  * scmd_eh_abort_handler - Handle command aborts
116  * @work:       command to be aborted.
117  */
118 void
119 scmd_eh_abort_handler(struct work_struct *work)
120 {
121         struct scsi_cmnd *scmd =
122                 container_of(work, struct scsi_cmnd, abort_work.work);
123         struct scsi_device *sdev = scmd->device;
124         int rtn;
125
126         if (scsi_host_eh_past_deadline(sdev->host)) {
127                 SCSI_LOG_ERROR_RECOVERY(3,
128                         scmd_printk(KERN_INFO, scmd,
129                                     "eh timeout, not aborting\n"));
130         } else {
131                 SCSI_LOG_ERROR_RECOVERY(3,
132                         scmd_printk(KERN_INFO, scmd,
133                                     "aborting command\n"));
134                 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
135                 if (rtn == SUCCESS) {
136                         set_host_byte(scmd, DID_TIME_OUT);
137                         if (scsi_host_eh_past_deadline(sdev->host)) {
138                                 SCSI_LOG_ERROR_RECOVERY(3,
139                                         scmd_printk(KERN_INFO, scmd,
140                                                     "eh timeout, not retrying "
141                                                     "aborted command\n"));
142                         } else if (!scsi_noretry_cmd(scmd) &&
143                             (++scmd->retries <= scmd->allowed)) {
144                                 SCSI_LOG_ERROR_RECOVERY(3,
145                                         scmd_printk(KERN_WARNING, scmd,
146                                                     "retry aborted command\n"));
147                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
148                                 return;
149                         } else {
150                                 SCSI_LOG_ERROR_RECOVERY(3,
151                                         scmd_printk(KERN_WARNING, scmd,
152                                                     "finish aborted command\n"));
153                                 scsi_finish_command(scmd);
154                                 return;
155                         }
156                 } else {
157                         SCSI_LOG_ERROR_RECOVERY(3,
158                                 scmd_printk(KERN_INFO, scmd,
159                                             "cmd abort %s\n",
160                                             (rtn == FAST_IO_FAIL) ?
161                                             "not send" : "failed"));
162                 }
163         }
164
165         if (!scsi_eh_scmd_add(scmd, 0)) {
166                 SCSI_LOG_ERROR_RECOVERY(3,
167                         scmd_printk(KERN_WARNING, scmd,
168                                     "terminate aborted command\n"));
169                 set_host_byte(scmd, DID_TIME_OUT);
170                 scsi_finish_command(scmd);
171         }
172 }
173
174 /**
175  * scsi_abort_command - schedule a command abort
176  * @scmd:       scmd to abort.
177  *
178  * We only need to abort commands after a command timeout
179  */
180 static int
181 scsi_abort_command(struct scsi_cmnd *scmd)
182 {
183         struct scsi_device *sdev = scmd->device;
184         struct Scsi_Host *shost = sdev->host;
185         unsigned long flags;
186
187         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
188                 /*
189                  * Retry after abort failed, escalate to next level.
190                  */
191                 scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
192                 SCSI_LOG_ERROR_RECOVERY(3,
193                         scmd_printk(KERN_INFO, scmd,
194                                     "previous abort failed\n"));
195                 BUG_ON(delayed_work_pending(&scmd->abort_work));
196                 return FAILED;
197         }
198
199         /*
200          * Do not try a command abort if
201          * SCSI EH has already started.
202          */
203         spin_lock_irqsave(shost->host_lock, flags);
204         if (scsi_host_in_recovery(shost)) {
205                 spin_unlock_irqrestore(shost->host_lock, flags);
206                 SCSI_LOG_ERROR_RECOVERY(3,
207                         scmd_printk(KERN_INFO, scmd,
208                                     "not aborting, host in recovery\n"));
209                 return FAILED;
210         }
211
212         if (shost->eh_deadline != -1 && !shost->last_reset)
213                 shost->last_reset = jiffies;
214         spin_unlock_irqrestore(shost->host_lock, flags);
215
216         scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
217         SCSI_LOG_ERROR_RECOVERY(3,
218                 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
219         queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
220         return SUCCESS;
221 }
222
223 /**
224  * scsi_eh_scmd_add - add scsi cmd to error handling.
225  * @scmd:       scmd to run eh on.
226  * @eh_flag:    optional SCSI_EH flag.
227  *
228  * Return value:
229  *      0 on failure.
230  */
231 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
232 {
233         struct Scsi_Host *shost = scmd->device->host;
234         unsigned long flags;
235         int ret = 0;
236
237         if (!shost->ehandler)
238                 return 0;
239
240         spin_lock_irqsave(shost->host_lock, flags);
241         if (scsi_host_set_state(shost, SHOST_RECOVERY))
242                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
243                         goto out_unlock;
244
245         if (shost->eh_deadline != -1 && !shost->last_reset)
246                 shost->last_reset = jiffies;
247
248         ret = 1;
249         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
250                 eh_flag &= ~SCSI_EH_CANCEL_CMD;
251         scmd->eh_eflags |= eh_flag;
252         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
253         shost->host_failed++;
254         scsi_eh_wakeup(shost);
255  out_unlock:
256         spin_unlock_irqrestore(shost->host_lock, flags);
257         return ret;
258 }
259
260 /**
261  * scsi_times_out - Timeout function for normal scsi commands.
262  * @req:        request that is timing out.
263  *
264  * Notes:
265  *     We do not need to lock this.  There is the potential for a race
266  *     only in that the normal completion handling might run, but if the
267  *     normal completion function determines that the timer has already
268  *     fired, then it mustn't do anything.
269  */
270 enum blk_eh_timer_return scsi_times_out(struct request *req)
271 {
272         struct scsi_cmnd *scmd = req->special;
273         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
274         struct Scsi_Host *host = scmd->device->host;
275
276         trace_scsi_dispatch_cmd_timeout(scmd);
277         scsi_log_completion(scmd, TIMEOUT_ERROR);
278
279         if (host->eh_deadline != -1 && !host->last_reset)
280                 host->last_reset = jiffies;
281
282         if (host->transportt->eh_timed_out)
283                 rtn = host->transportt->eh_timed_out(scmd);
284         else if (host->hostt->eh_timed_out)
285                 rtn = host->hostt->eh_timed_out(scmd);
286
287         if (rtn == BLK_EH_NOT_HANDLED) {
288                 if (!host->hostt->no_async_abort &&
289                     scsi_abort_command(scmd) == SUCCESS)
290                         return BLK_EH_NOT_HANDLED;
291
292                 set_host_byte(scmd, DID_TIME_OUT);
293                 if (!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))
294                         rtn = BLK_EH_HANDLED;
295         }
296
297         return rtn;
298 }
299
300 /**
301  * scsi_block_when_processing_errors - Prevent cmds from being queued.
302  * @sdev:       Device on which we are performing recovery.
303  *
304  * Description:
305  *     We block until the host is out of error recovery, and then check to
306  *     see whether the host or the device is offline.
307  *
308  * Return value:
309  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
310  */
311 int scsi_block_when_processing_errors(struct scsi_device *sdev)
312 {
313         int online;
314
315         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
316
317         online = scsi_device_online(sdev);
318
319         SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_INFO, sdev,
320                 "%s: rtn: %d\n", __func__, online));
321
322         return online;
323 }
324 EXPORT_SYMBOL(scsi_block_when_processing_errors);
325
326 #ifdef CONFIG_SCSI_LOGGING
327 /**
328  * scsi_eh_prt_fail_stats - Log info on failures.
329  * @shost:      scsi host being recovered.
330  * @work_q:     Queue of scsi cmds to process.
331  */
332 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
333                                           struct list_head *work_q)
334 {
335         struct scsi_cmnd *scmd;
336         struct scsi_device *sdev;
337         int total_failures = 0;
338         int cmd_failed = 0;
339         int cmd_cancel = 0;
340         int devices_failed = 0;
341
342         shost_for_each_device(sdev, shost) {
343                 list_for_each_entry(scmd, work_q, eh_entry) {
344                         if (scmd->device == sdev) {
345                                 ++total_failures;
346                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
347                                         ++cmd_cancel;
348                                 else
349                                         ++cmd_failed;
350                         }
351                 }
352
353                 if (cmd_cancel || cmd_failed) {
354                         SCSI_LOG_ERROR_RECOVERY(3,
355                                 shost_printk(KERN_INFO, shost,
356                                             "%s: cmds failed: %d, cancel: %d\n",
357                                             __func__, cmd_failed,
358                                             cmd_cancel));
359                         cmd_cancel = 0;
360                         cmd_failed = 0;
361                         ++devices_failed;
362                 }
363         }
364
365         SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
366                                    "Total of %d commands on %d"
367                                    " devices require eh work\n",
368                                    total_failures, devices_failed));
369 }
370 #endif
371
372  /**
373  * scsi_report_lun_change - Set flag on all *other* devices on the same target
374  *                          to indicate that a UNIT ATTENTION is expected.
375  * @sdev:       Device reporting the UNIT ATTENTION
376  */
377 static void scsi_report_lun_change(struct scsi_device *sdev)
378 {
379         sdev->sdev_target->expecting_lun_change = 1;
380 }
381
382 /**
383  * scsi_report_sense - Examine scsi sense information and log messages for
384  *                     certain conditions, also issue uevents for some of them.
385  * @sdev:       Device reporting the sense code
386  * @sshdr:      sshdr to be examined
387  */
388 static void scsi_report_sense(struct scsi_device *sdev,
389                               struct scsi_sense_hdr *sshdr)
390 {
391         enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
392
393         if (sshdr->sense_key == UNIT_ATTENTION) {
394                 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
395                         evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
396                         sdev_printk(KERN_WARNING, sdev,
397                                     "Inquiry data has changed");
398                 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
399                         evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
400                         scsi_report_lun_change(sdev);
401                         sdev_printk(KERN_WARNING, sdev,
402                                     "Warning! Received an indication that the "
403                                     "LUN assignments on this target have "
404                                     "changed. The Linux SCSI layer does not "
405                                     "automatically remap LUN assignments.\n");
406                 } else if (sshdr->asc == 0x3f)
407                         sdev_printk(KERN_WARNING, sdev,
408                                     "Warning! Received an indication that the "
409                                     "operating parameters on this target have "
410                                     "changed. The Linux SCSI layer does not "
411                                     "automatically adjust these parameters.\n");
412
413                 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
414                         evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
415                         sdev_printk(KERN_WARNING, sdev,
416                                     "Warning! Received an indication that the "
417                                     "LUN reached a thin provisioning soft "
418                                     "threshold.\n");
419                 }
420
421                 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
422                         evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
423                         sdev_printk(KERN_WARNING, sdev,
424                                     "Mode parameters changed");
425                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
426                         evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
427                         sdev_printk(KERN_WARNING, sdev,
428                                     "Asymmetric access state changed");
429                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
430                         evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
431                         sdev_printk(KERN_WARNING, sdev,
432                                     "Capacity data has changed");
433                 } else if (sshdr->asc == 0x2a)
434                         sdev_printk(KERN_WARNING, sdev,
435                                     "Parameters changed");
436         }
437
438         if (evt_type != SDEV_EVT_MAXBITS) {
439                 set_bit(evt_type, sdev->pending_events);
440                 schedule_work(&sdev->event_work);
441         }
442 }
443
444 /**
445  * scsi_check_sense - Examine scsi cmd sense
446  * @scmd:       Cmd to have sense checked.
447  *
448  * Return value:
449  *      SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
450  *
451  * Notes:
452  *      When a deferred error is detected the current command has
453  *      not been executed and needs retrying.
454  */
455 static int scsi_check_sense(struct scsi_cmnd *scmd)
456 {
457         struct scsi_device *sdev = scmd->device;
458         struct scsi_sense_hdr sshdr;
459
460         if (! scsi_command_normalize_sense(scmd, &sshdr))
461                 return FAILED;  /* no valid sense data */
462
463         scsi_report_sense(sdev, &sshdr);
464
465         if (scsi_sense_is_deferred(&sshdr))
466                 return NEEDS_RETRY;
467
468         if (sdev->handler && sdev->handler->check_sense) {
469                 int rc;
470
471                 rc = sdev->handler->check_sense(sdev, &sshdr);
472                 if (rc != SCSI_RETURN_NOT_HANDLED)
473                         return rc;
474                 /* handler does not care. Drop down to default handling */
475         }
476
477         if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
478                 /*
479                  * nasty: for mid-layer issued TURs, we need to return the
480                  * actual sense data without any recovery attempt.  For eh
481                  * issued ones, we need to try to recover and interpret
482                  */
483                 return SUCCESS;
484
485         /*
486          * Previous logic looked for FILEMARK, EOM or ILI which are
487          * mainly associated with tapes and returned SUCCESS.
488          */
489         if (sshdr.response_code == 0x70) {
490                 /* fixed format */
491                 if (scmd->sense_buffer[2] & 0xe0)
492                         return SUCCESS;
493         } else {
494                 /*
495                  * descriptor format: look for "stream commands sense data
496                  * descriptor" (see SSC-3). Assume single sense data
497                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
498                  */
499                 if ((sshdr.additional_length > 3) &&
500                     (scmd->sense_buffer[8] == 0x4) &&
501                     (scmd->sense_buffer[11] & 0xe0))
502                         return SUCCESS;
503         }
504
505         switch (sshdr.sense_key) {
506         case NO_SENSE:
507                 return SUCCESS;
508         case RECOVERED_ERROR:
509                 return /* soft_error */ SUCCESS;
510
511         case ABORTED_COMMAND:
512                 if (sshdr.asc == 0x10) /* DIF */
513                         return SUCCESS;
514
515                 return NEEDS_RETRY;
516         case NOT_READY:
517         case UNIT_ATTENTION:
518                 /*
519                  * if we are expecting a cc/ua because of a bus reset that we
520                  * performed, treat this just as a retry.  otherwise this is
521                  * information that we should pass up to the upper-level driver
522                  * so that we can deal with it there.
523                  */
524                 if (scmd->device->expecting_cc_ua) {
525                         /*
526                          * Because some device does not queue unit
527                          * attentions correctly, we carefully check
528                          * additional sense code and qualifier so as
529                          * not to squash media change unit attention.
530                          */
531                         if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
532                                 scmd->device->expecting_cc_ua = 0;
533                                 return NEEDS_RETRY;
534                         }
535                 }
536                 /*
537                  * we might also expect a cc/ua if another LUN on the target
538                  * reported a UA with an ASC/ASCQ of 3F 0E -
539                  * REPORTED LUNS DATA HAS CHANGED.
540                  */
541                 if (scmd->device->sdev_target->expecting_lun_change &&
542                     sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
543                         return NEEDS_RETRY;
544                 /*
545                  * if the device is in the process of becoming ready, we
546                  * should retry.
547                  */
548                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
549                         return NEEDS_RETRY;
550                 /*
551                  * if the device is not started, we need to wake
552                  * the error handler to start the motor
553                  */
554                 if (scmd->device->allow_restart &&
555                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
556                         return FAILED;
557                 /*
558                  * Pass the UA upwards for a determination in the completion
559                  * functions.
560                  */
561                 return SUCCESS;
562
563                 /* these are not supported */
564         case DATA_PROTECT:
565                 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
566                         /* Thin provisioning hard threshold reached */
567                         set_host_byte(scmd, DID_ALLOC_FAILURE);
568                         return SUCCESS;
569                 }
570         case COPY_ABORTED:
571         case VOLUME_OVERFLOW:
572         case MISCOMPARE:
573         case BLANK_CHECK:
574                 set_host_byte(scmd, DID_TARGET_FAILURE);
575                 return SUCCESS;
576
577         case MEDIUM_ERROR:
578                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
579                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
580                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
581                         set_host_byte(scmd, DID_MEDIUM_ERROR);
582                         return SUCCESS;
583                 }
584                 return NEEDS_RETRY;
585
586         case HARDWARE_ERROR:
587                 if (scmd->device->retry_hwerror)
588                         return ADD_TO_MLQUEUE;
589                 else
590                         set_host_byte(scmd, DID_TARGET_FAILURE);
591
592         case ILLEGAL_REQUEST:
593                 if (sshdr.asc == 0x20 || /* Invalid command operation code */
594                     sshdr.asc == 0x21 || /* Logical block address out of range */
595                     sshdr.asc == 0x24 || /* Invalid field in cdb */
596                     sshdr.asc == 0x26) { /* Parameter value invalid */
597                         set_host_byte(scmd, DID_TARGET_FAILURE);
598                 }
599                 return SUCCESS;
600
601         default:
602                 return SUCCESS;
603         }
604 }
605
606 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
607 {
608         struct scsi_host_template *sht = sdev->host->hostt;
609         struct scsi_device *tmp_sdev;
610
611         if (!sht->track_queue_depth ||
612             sdev->queue_depth >= sdev->max_queue_depth)
613                 return;
614
615         if (time_before(jiffies,
616             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
617                 return;
618
619         if (time_before(jiffies,
620             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
621                 return;
622
623         /*
624          * Walk all devices of a target and do
625          * ramp up on them.
626          */
627         shost_for_each_device(tmp_sdev, sdev->host) {
628                 if (tmp_sdev->channel != sdev->channel ||
629                     tmp_sdev->id != sdev->id ||
630                     tmp_sdev->queue_depth == sdev->max_queue_depth)
631                         continue;
632
633                 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
634                 sdev->last_queue_ramp_up = jiffies;
635         }
636 }
637
638 static void scsi_handle_queue_full(struct scsi_device *sdev)
639 {
640         struct scsi_host_template *sht = sdev->host->hostt;
641         struct scsi_device *tmp_sdev;
642
643         if (!sht->track_queue_depth)
644                 return;
645
646         shost_for_each_device(tmp_sdev, sdev->host) {
647                 if (tmp_sdev->channel != sdev->channel ||
648                     tmp_sdev->id != sdev->id)
649                         continue;
650                 /*
651                  * We do not know the number of commands that were at
652                  * the device when we got the queue full so we start
653                  * from the highest possible value and work our way down.
654                  */
655                 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
656         }
657 }
658
659 /**
660  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
661  * @scmd:       SCSI cmd to examine.
662  *
663  * Notes:
664  *    This is *only* called when we are examining the status of commands
665  *    queued during error recovery.  the main difference here is that we
666  *    don't allow for the possibility of retries here, and we are a lot
667  *    more restrictive about what we consider acceptable.
668  */
669 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
670 {
671         /*
672          * first check the host byte, to see if there is anything in there
673          * that would indicate what we need to do.
674          */
675         if (host_byte(scmd->result) == DID_RESET) {
676                 /*
677                  * rats.  we are already in the error handler, so we now
678                  * get to try and figure out what to do next.  if the sense
679                  * is valid, we have a pretty good idea of what to do.
680                  * if not, we mark it as FAILED.
681                  */
682                 return scsi_check_sense(scmd);
683         }
684         if (host_byte(scmd->result) != DID_OK)
685                 return FAILED;
686
687         /*
688          * next, check the message byte.
689          */
690         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
691                 return FAILED;
692
693         /*
694          * now, check the status byte to see if this indicates
695          * anything special.
696          */
697         switch (status_byte(scmd->result)) {
698         case GOOD:
699                 scsi_handle_queue_ramp_up(scmd->device);
700         case COMMAND_TERMINATED:
701                 return SUCCESS;
702         case CHECK_CONDITION:
703                 return scsi_check_sense(scmd);
704         case CONDITION_GOOD:
705         case INTERMEDIATE_GOOD:
706         case INTERMEDIATE_C_GOOD:
707                 /*
708                  * who knows?  FIXME(eric)
709                  */
710                 return SUCCESS;
711         case RESERVATION_CONFLICT:
712                 if (scmd->cmnd[0] == TEST_UNIT_READY)
713                         /* it is a success, we probed the device and
714                          * found it */
715                         return SUCCESS;
716                 /* otherwise, we failed to send the command */
717                 return FAILED;
718         case QUEUE_FULL:
719                 scsi_handle_queue_full(scmd->device);
720                 /* fall through */
721         case BUSY:
722                 return NEEDS_RETRY;
723         default:
724                 return FAILED;
725         }
726         return FAILED;
727 }
728
729 /**
730  * scsi_eh_done - Completion function for error handling.
731  * @scmd:       Cmd that is done.
732  */
733 static void scsi_eh_done(struct scsi_cmnd *scmd)
734 {
735         struct completion *eh_action;
736
737         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
738                         "%s result: %x\n", __func__, scmd->result));
739
740         eh_action = scmd->device->host->eh_action;
741         if (eh_action)
742                 complete(eh_action);
743 }
744
745 /**
746  * scsi_try_host_reset - ask host adapter to reset itself
747  * @scmd:       SCSI cmd to send host reset.
748  */
749 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
750 {
751         unsigned long flags;
752         int rtn;
753         struct Scsi_Host *host = scmd->device->host;
754         struct scsi_host_template *hostt = host->hostt;
755
756         SCSI_LOG_ERROR_RECOVERY(3,
757                 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
758
759         if (!hostt->eh_host_reset_handler)
760                 return FAILED;
761
762         rtn = hostt->eh_host_reset_handler(scmd);
763
764         if (rtn == SUCCESS) {
765                 if (!hostt->skip_settle_delay)
766                         ssleep(HOST_RESET_SETTLE_TIME);
767                 spin_lock_irqsave(host->host_lock, flags);
768                 scsi_report_bus_reset(host, scmd_channel(scmd));
769                 spin_unlock_irqrestore(host->host_lock, flags);
770         }
771
772         return rtn;
773 }
774
775 /**
776  * scsi_try_bus_reset - ask host to perform a bus reset
777  * @scmd:       SCSI cmd to send bus reset.
778  */
779 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
780 {
781         unsigned long flags;
782         int rtn;
783         struct Scsi_Host *host = scmd->device->host;
784         struct scsi_host_template *hostt = host->hostt;
785
786         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
787                 "%s: Snd Bus RST\n", __func__));
788
789         if (!hostt->eh_bus_reset_handler)
790                 return FAILED;
791
792         rtn = hostt->eh_bus_reset_handler(scmd);
793
794         if (rtn == SUCCESS) {
795                 if (!hostt->skip_settle_delay)
796                         ssleep(BUS_RESET_SETTLE_TIME);
797                 spin_lock_irqsave(host->host_lock, flags);
798                 scsi_report_bus_reset(host, scmd_channel(scmd));
799                 spin_unlock_irqrestore(host->host_lock, flags);
800         }
801
802         return rtn;
803 }
804
805 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
806 {
807         sdev->was_reset = 1;
808         sdev->expecting_cc_ua = 1;
809 }
810
811 /**
812  * scsi_try_target_reset - Ask host to perform a target reset
813  * @scmd:       SCSI cmd used to send a target reset
814  *
815  * Notes:
816  *    There is no timeout for this operation.  if this operation is
817  *    unreliable for a given host, then the host itself needs to put a
818  *    timer on it, and set the host back to a consistent state prior to
819  *    returning.
820  */
821 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
822 {
823         unsigned long flags;
824         int rtn;
825         struct Scsi_Host *host = scmd->device->host;
826         struct scsi_host_template *hostt = host->hostt;
827
828         if (!hostt->eh_target_reset_handler)
829                 return FAILED;
830
831         rtn = hostt->eh_target_reset_handler(scmd);
832         if (rtn == SUCCESS) {
833                 spin_lock_irqsave(host->host_lock, flags);
834                 __starget_for_each_device(scsi_target(scmd->device), NULL,
835                                           __scsi_report_device_reset);
836                 spin_unlock_irqrestore(host->host_lock, flags);
837         }
838
839         return rtn;
840 }
841
842 /**
843  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
844  * @scmd:       SCSI cmd used to send BDR
845  *
846  * Notes:
847  *    There is no timeout for this operation.  if this operation is
848  *    unreliable for a given host, then the host itself needs to put a
849  *    timer on it, and set the host back to a consistent state prior to
850  *    returning.
851  */
852 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
853 {
854         int rtn;
855         struct scsi_host_template *hostt = scmd->device->host->hostt;
856
857         if (!hostt->eh_device_reset_handler)
858                 return FAILED;
859
860         rtn = hostt->eh_device_reset_handler(scmd);
861         if (rtn == SUCCESS)
862                 __scsi_report_device_reset(scmd->device, NULL);
863         return rtn;
864 }
865
866 /**
867  * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
868  * @hostt:      SCSI driver host template
869  * @scmd:       SCSI cmd used to send a target reset
870  *
871  * Return value:
872  *      SUCCESS, FAILED, or FAST_IO_FAIL
873  *
874  * Notes:
875  *    SUCCESS does not necessarily indicate that the command
876  *    has been aborted; it only indicates that the LLDDs
877  *    has cleared all references to that command.
878  *    LLDDs should return FAILED only if an abort was required
879  *    but could not be executed. LLDDs should return FAST_IO_FAIL
880  *    if the device is temporarily unavailable (eg due to a
881  *    link down on FibreChannel)
882  */
883 static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt,
884                                  struct scsi_cmnd *scmd)
885 {
886         if (!hostt->eh_abort_handler)
887                 return FAILED;
888
889         return hostt->eh_abort_handler(scmd);
890 }
891
892 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
893 {
894         if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
895                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
896                         if (scsi_try_target_reset(scmd) != SUCCESS)
897                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
898                                         scsi_try_host_reset(scmd);
899 }
900
901 /**
902  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
903  * @scmd:       SCSI command structure to hijack
904  * @ses:        structure to save restore information
905  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
906  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
907  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
908  *
909  * This function is used to save a scsi command information before re-execution
910  * as part of the error recovery process.  If @sense_bytes is 0 the command
911  * sent must be one that does not transfer any data.  If @sense_bytes != 0
912  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
913  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
914  */
915 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
916                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
917 {
918         struct scsi_device *sdev = scmd->device;
919
920         /*
921          * We need saved copies of a number of fields - this is because
922          * error handling may need to overwrite these with different values
923          * to run different commands, and once error handling is complete,
924          * we will need to restore these values prior to running the actual
925          * command.
926          */
927         ses->cmd_len = scmd->cmd_len;
928         ses->cmnd = scmd->cmnd;
929         ses->data_direction = scmd->sc_data_direction;
930         ses->sdb = scmd->sdb;
931         ses->next_rq = scmd->request->next_rq;
932         ses->result = scmd->result;
933         ses->underflow = scmd->underflow;
934         ses->prot_op = scmd->prot_op;
935
936         scmd->prot_op = SCSI_PROT_NORMAL;
937         scmd->eh_eflags = 0;
938         scmd->cmnd = ses->eh_cmnd;
939         memset(scmd->cmnd, 0, BLK_MAX_CDB);
940         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
941         scmd->request->next_rq = NULL;
942         scmd->result = 0;
943
944         if (sense_bytes) {
945                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
946                                          sense_bytes);
947                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
948                             scmd->sdb.length);
949                 scmd->sdb.table.sgl = &ses->sense_sgl;
950                 scmd->sc_data_direction = DMA_FROM_DEVICE;
951                 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
952                 scmd->cmnd[0] = REQUEST_SENSE;
953                 scmd->cmnd[4] = scmd->sdb.length;
954                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
955         } else {
956                 scmd->sc_data_direction = DMA_NONE;
957                 if (cmnd) {
958                         BUG_ON(cmnd_size > BLK_MAX_CDB);
959                         memcpy(scmd->cmnd, cmnd, cmnd_size);
960                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
961                 }
962         }
963
964         scmd->underflow = 0;
965
966         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
967                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
968                         (sdev->lun << 5 & 0xe0);
969
970         /*
971          * Zero the sense buffer.  The scsi spec mandates that any
972          * untransferred sense data should be interpreted as being zero.
973          */
974         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
975 }
976 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
977
978 /**
979  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
980  * @scmd:       SCSI command structure to restore
981  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
982  *
983  * Undo any damage done by above scsi_eh_prep_cmnd().
984  */
985 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
986 {
987         /*
988          * Restore original data
989          */
990         scmd->cmd_len = ses->cmd_len;
991         scmd->cmnd = ses->cmnd;
992         scmd->sc_data_direction = ses->data_direction;
993         scmd->sdb = ses->sdb;
994         scmd->request->next_rq = ses->next_rq;
995         scmd->result = ses->result;
996         scmd->underflow = ses->underflow;
997         scmd->prot_op = ses->prot_op;
998 }
999 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1000
1001 /**
1002  * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
1003  * @scmd:       SCSI command structure to hijack
1004  * @cmnd:       CDB to send
1005  * @cmnd_size:  size in bytes of @cmnd
1006  * @timeout:    timeout for this request
1007  * @sense_bytes: size of sense data to copy or 0
1008  *
1009  * This function is used to send a scsi command down to a target device
1010  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1011  *
1012  * Return value:
1013  *    SUCCESS or FAILED or NEEDS_RETRY
1014  */
1015 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
1016                              int cmnd_size, int timeout, unsigned sense_bytes)
1017 {
1018         struct scsi_device *sdev = scmd->device;
1019         struct Scsi_Host *shost = sdev->host;
1020         DECLARE_COMPLETION_ONSTACK(done);
1021         unsigned long timeleft = timeout;
1022         struct scsi_eh_save ses;
1023         const unsigned long stall_for = msecs_to_jiffies(100);
1024         int rtn;
1025
1026 retry:
1027         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1028         shost->eh_action = &done;
1029
1030         scsi_log_send(scmd);
1031         scmd->scsi_done = scsi_eh_done;
1032         rtn = shost->hostt->queuecommand(shost, scmd);
1033         if (rtn) {
1034                 if (timeleft > stall_for) {
1035                         scsi_eh_restore_cmnd(scmd, &ses);
1036                         timeleft -= stall_for;
1037                         msleep(jiffies_to_msecs(stall_for));
1038                         goto retry;
1039                 }
1040                 /* signal not to enter either branch of the if () below */
1041                 timeleft = 0;
1042                 rtn = FAILED;
1043         } else {
1044                 timeleft = wait_for_completion_timeout(&done, timeout);
1045                 rtn = SUCCESS;
1046         }
1047
1048         shost->eh_action = NULL;
1049
1050         scsi_log_completion(scmd, rtn);
1051
1052         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1053                         "%s timeleft: %ld\n",
1054                         __func__, timeleft));
1055
1056         /*
1057          * If there is time left scsi_eh_done got called, and we will examine
1058          * the actual status codes to see whether the command actually did
1059          * complete normally, else if we have a zero return and no time left,
1060          * the command must still be pending, so abort it and return FAILED.
1061          * If we never actually managed to issue the command, because
1062          * ->queuecommand() kept returning non zero, use the rtn = FAILED
1063          * value above (so don't execute either branch of the if)
1064          */
1065         if (timeleft) {
1066                 rtn = scsi_eh_completed_normally(scmd);
1067                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1068                         "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1069
1070                 switch (rtn) {
1071                 case SUCCESS:
1072                 case NEEDS_RETRY:
1073                 case FAILED:
1074                         break;
1075                 case ADD_TO_MLQUEUE:
1076                         rtn = NEEDS_RETRY;
1077                         break;
1078                 default:
1079                         rtn = FAILED;
1080                         break;
1081                 }
1082         } else if (rtn != FAILED) {
1083                 scsi_abort_eh_cmnd(scmd);
1084                 rtn = FAILED;
1085         }
1086
1087         scsi_eh_restore_cmnd(scmd, &ses);
1088
1089         return rtn;
1090 }
1091
1092 /**
1093  * scsi_request_sense - Request sense data from a particular target.
1094  * @scmd:       SCSI cmd for request sense.
1095  *
1096  * Notes:
1097  *    Some hosts automatically obtain this information, others require
1098  *    that we obtain it on our own. This function will *not* return until
1099  *    the command either times out, or it completes.
1100  */
1101 static int scsi_request_sense(struct scsi_cmnd *scmd)
1102 {
1103         return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1104 }
1105
1106 static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
1107 {
1108         if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
1109                 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1110                 if (sdrv->eh_action)
1111                         rtn = sdrv->eh_action(scmd, rtn);
1112         }
1113         return rtn;
1114 }
1115
1116 /**
1117  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1118  * @scmd:       Original SCSI cmd that eh has finished.
1119  * @done_q:     Queue for processed commands.
1120  *
1121  * Notes:
1122  *    We don't want to use the normal command completion while we are are
1123  *    still handling errors - it may cause other commands to be queued,
1124  *    and that would disturb what we are doing.  Thus we really want to
1125  *    keep a list of pending commands for final completion, and once we
1126  *    are ready to leave error handling we handle completion for real.
1127  */
1128 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1129 {
1130         scmd->device->host->host_failed--;
1131         scmd->eh_eflags = 0;
1132         list_move_tail(&scmd->eh_entry, done_q);
1133 }
1134 EXPORT_SYMBOL(scsi_eh_finish_cmd);
1135
1136 /**
1137  * scsi_eh_get_sense - Get device sense data.
1138  * @work_q:     Queue of commands to process.
1139  * @done_q:     Queue of processed commands.
1140  *
1141  * Description:
1142  *    See if we need to request sense information.  if so, then get it
1143  *    now, so we have a better idea of what to do.
1144  *
1145  * Notes:
1146  *    This has the unfortunate side effect that if a shost adapter does
1147  *    not automatically request sense information, we end up shutting
1148  *    it down before we request it.
1149  *
1150  *    All drivers should request sense information internally these days,
1151  *    so for now all I have to say is tough noogies if you end up in here.
1152  *
1153  *    XXX: Long term this code should go away, but that needs an audit of
1154  *         all LLDDs first.
1155  */
1156 int scsi_eh_get_sense(struct list_head *work_q,
1157                       struct list_head *done_q)
1158 {
1159         struct scsi_cmnd *scmd, *next;
1160         struct Scsi_Host *shost;
1161         int rtn;
1162
1163         /*
1164          * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1165          * should not get sense.
1166          */
1167         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1168                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
1169                     (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1170                     SCSI_SENSE_VALID(scmd))
1171                         continue;
1172
1173                 shost = scmd->device->host;
1174                 if (scsi_host_eh_past_deadline(shost)) {
1175                         SCSI_LOG_ERROR_RECOVERY(3,
1176                                 scmd_printk(KERN_INFO, scmd,
1177                                             "%s: skip request sense, past eh deadline\n",
1178                                              current->comm));
1179                         break;
1180                 }
1181                 if (status_byte(scmd->result) != CHECK_CONDITION)
1182                         /*
1183                          * don't request sense if there's no check condition
1184                          * status because the error we're processing isn't one
1185                          * that has a sense code (and some devices get
1186                          * confused by sense requests out of the blue)
1187                          */
1188                         continue;
1189
1190                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1191                                                   "%s: requesting sense\n",
1192                                                   current->comm));
1193                 rtn = scsi_request_sense(scmd);
1194                 if (rtn != SUCCESS)
1195                         continue;
1196
1197                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1198                         "sense requested, result %x\n", scmd->result));
1199                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1200
1201                 rtn = scsi_decide_disposition(scmd);
1202
1203                 /*
1204                  * if the result was normal, then just pass it along to the
1205                  * upper level.
1206                  */
1207                 if (rtn == SUCCESS)
1208                         /* we don't want this command reissued, just
1209                          * finished with the sense data, so set
1210                          * retries to the max allowed to ensure it
1211                          * won't get reissued */
1212                         scmd->retries = scmd->allowed;
1213                 else if (rtn != NEEDS_RETRY)
1214                         continue;
1215
1216                 scsi_eh_finish_cmd(scmd, done_q);
1217         }
1218
1219         return list_empty(work_q);
1220 }
1221 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1222
1223 /**
1224  * scsi_eh_tur - Send TUR to device.
1225  * @scmd:       &scsi_cmnd to send TUR
1226  *
1227  * Return value:
1228  *    0 - Device is ready. 1 - Device NOT ready.
1229  */
1230 static int scsi_eh_tur(struct scsi_cmnd *scmd)
1231 {
1232         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1233         int retry_cnt = 1, rtn;
1234
1235 retry_tur:
1236         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1237                                 scmd->device->eh_timeout, 0);
1238
1239         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1240                 "%s return: %x\n", __func__, rtn));
1241
1242         switch (rtn) {
1243         case NEEDS_RETRY:
1244                 if (retry_cnt--)
1245                         goto retry_tur;
1246                 /*FALLTHRU*/
1247         case SUCCESS:
1248                 return 0;
1249         default:
1250                 return 1;
1251         }
1252 }
1253
1254 /**
1255  * scsi_eh_test_devices - check if devices are responding from error recovery.
1256  * @cmd_list:   scsi commands in error recovery.
1257  * @work_q:     queue for commands which still need more error recovery
1258  * @done_q:     queue for commands which are finished
1259  * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
1260  *
1261  * Decription:
1262  *    Tests if devices are in a working state.  Commands to devices now in
1263  *    a working state are sent to the done_q while commands to devices which
1264  *    are still failing to respond are returned to the work_q for more
1265  *    processing.
1266  **/
1267 static int scsi_eh_test_devices(struct list_head *cmd_list,
1268                                 struct list_head *work_q,
1269                                 struct list_head *done_q, int try_stu)
1270 {
1271         struct scsi_cmnd *scmd, *next;
1272         struct scsi_device *sdev;
1273         int finish_cmds;
1274
1275         while (!list_empty(cmd_list)) {
1276                 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1277                 sdev = scmd->device;
1278
1279                 if (!try_stu) {
1280                         if (scsi_host_eh_past_deadline(sdev->host)) {
1281                                 /* Push items back onto work_q */
1282                                 list_splice_init(cmd_list, work_q);
1283                                 SCSI_LOG_ERROR_RECOVERY(3,
1284                                         sdev_printk(KERN_INFO, sdev,
1285                                                     "%s: skip test device, past eh deadline",
1286                                                     current->comm));
1287                                 break;
1288                         }
1289                 }
1290
1291                 finish_cmds = !scsi_device_online(scmd->device) ||
1292                         (try_stu && !scsi_eh_try_stu(scmd) &&
1293                          !scsi_eh_tur(scmd)) ||
1294                         !scsi_eh_tur(scmd);
1295
1296                 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1297                         if (scmd->device == sdev) {
1298                                 if (finish_cmds &&
1299                                     (try_stu ||
1300                                      scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1301                                         scsi_eh_finish_cmd(scmd, done_q);
1302                                 else
1303                                         list_move_tail(&scmd->eh_entry, work_q);
1304                         }
1305         }
1306         return list_empty(work_q);
1307 }
1308
1309
1310 /**
1311  * scsi_eh_abort_cmds - abort pending commands.
1312  * @work_q:     &list_head for pending commands.
1313  * @done_q:     &list_head for processed commands.
1314  *
1315  * Decription:
1316  *    Try and see whether or not it makes sense to try and abort the
1317  *    running command.  This only works out to be the case if we have one
1318  *    command that has timed out.  If the command simply failed, it makes
1319  *    no sense to try and abort the command, since as far as the shost
1320  *    adapter is concerned, it isn't running.
1321  */
1322 static int scsi_eh_abort_cmds(struct list_head *work_q,
1323                               struct list_head *done_q)
1324 {
1325         struct scsi_cmnd *scmd, *next;
1326         LIST_HEAD(check_list);
1327         int rtn;
1328         struct Scsi_Host *shost;
1329
1330         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1331                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1332                         continue;
1333                 shost = scmd->device->host;
1334                 if (scsi_host_eh_past_deadline(shost)) {
1335                         list_splice_init(&check_list, work_q);
1336                         SCSI_LOG_ERROR_RECOVERY(3,
1337                                 scmd_printk(KERN_INFO, scmd,
1338                                             "%s: skip aborting cmd, past eh deadline\n",
1339                                             current->comm));
1340                         return list_empty(work_q);
1341                 }
1342                 SCSI_LOG_ERROR_RECOVERY(3,
1343                         scmd_printk(KERN_INFO, scmd,
1344                                      "%s: aborting cmd\n", current->comm));
1345                 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1346                 if (rtn == FAILED) {
1347                         SCSI_LOG_ERROR_RECOVERY(3,
1348                                 scmd_printk(KERN_INFO, scmd,
1349                                             "%s: aborting cmd failed\n",
1350                                              current->comm));
1351                         list_splice_init(&check_list, work_q);
1352                         return list_empty(work_q);
1353                 }
1354                 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1355                 if (rtn == FAST_IO_FAIL)
1356                         scsi_eh_finish_cmd(scmd, done_q);
1357                 else
1358                         list_move_tail(&scmd->eh_entry, &check_list);
1359         }
1360
1361         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1362 }
1363
1364 /**
1365  * scsi_eh_try_stu - Send START_UNIT to device.
1366  * @scmd:       &scsi_cmnd to send START_UNIT
1367  *
1368  * Return value:
1369  *    0 - Device is ready. 1 - Device NOT ready.
1370  */
1371 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1372 {
1373         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1374
1375         if (scmd->device->allow_restart) {
1376                 int i, rtn = NEEDS_RETRY;
1377
1378                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1379                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1380
1381                 if (rtn == SUCCESS)
1382                         return 0;
1383         }
1384
1385         return 1;
1386 }
1387
1388  /**
1389  * scsi_eh_stu - send START_UNIT if needed
1390  * @shost:      &scsi host being recovered.
1391  * @work_q:     &list_head for pending commands.
1392  * @done_q:     &list_head for processed commands.
1393  *
1394  * Notes:
1395  *    If commands are failing due to not ready, initializing command required,
1396  *      try revalidating the device, which will end up sending a start unit.
1397  */
1398 static int scsi_eh_stu(struct Scsi_Host *shost,
1399                               struct list_head *work_q,
1400                               struct list_head *done_q)
1401 {
1402         struct scsi_cmnd *scmd, *stu_scmd, *next;
1403         struct scsi_device *sdev;
1404
1405         shost_for_each_device(sdev, shost) {
1406                 if (scsi_host_eh_past_deadline(shost)) {
1407                         SCSI_LOG_ERROR_RECOVERY(3,
1408                                 sdev_printk(KERN_INFO, sdev,
1409                                             "%s: skip START_UNIT, past eh deadline\n",
1410                                             current->comm));
1411                         break;
1412                 }
1413                 stu_scmd = NULL;
1414                 list_for_each_entry(scmd, work_q, eh_entry)
1415                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1416                             scsi_check_sense(scmd) == FAILED ) {
1417                                 stu_scmd = scmd;
1418                                 break;
1419                         }
1420
1421                 if (!stu_scmd)
1422                         continue;
1423
1424                 SCSI_LOG_ERROR_RECOVERY(3,
1425                         sdev_printk(KERN_INFO, sdev,
1426                                      "%s: Sending START_UNIT\n",
1427                                     current->comm));
1428
1429                 if (!scsi_eh_try_stu(stu_scmd)) {
1430                         if (!scsi_device_online(sdev) ||
1431                             !scsi_eh_tur(stu_scmd)) {
1432                                 list_for_each_entry_safe(scmd, next,
1433                                                           work_q, eh_entry) {
1434                                         if (scmd->device == sdev &&
1435                                             scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1436                                                 scsi_eh_finish_cmd(scmd, done_q);
1437                                 }
1438                         }
1439                 } else {
1440                         SCSI_LOG_ERROR_RECOVERY(3,
1441                                 sdev_printk(KERN_INFO, sdev,
1442                                             "%s: START_UNIT failed\n",
1443                                             current->comm));
1444                 }
1445         }
1446
1447         return list_empty(work_q);
1448 }
1449
1450
1451 /**
1452  * scsi_eh_bus_device_reset - send bdr if needed
1453  * @shost:      scsi host being recovered.
1454  * @work_q:     &list_head for pending commands.
1455  * @done_q:     &list_head for processed commands.
1456  *
1457  * Notes:
1458  *    Try a bus device reset.  Still, look to see whether we have multiple
1459  *    devices that are jammed or not - if we have multiple devices, it
1460  *    makes no sense to try bus_device_reset - we really would need to try
1461  *    a bus_reset instead.
1462  */
1463 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1464                                     struct list_head *work_q,
1465                                     struct list_head *done_q)
1466 {
1467         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1468         struct scsi_device *sdev;
1469         int rtn;
1470
1471         shost_for_each_device(sdev, shost) {
1472                 if (scsi_host_eh_past_deadline(shost)) {
1473                         SCSI_LOG_ERROR_RECOVERY(3,
1474                                 sdev_printk(KERN_INFO, sdev,
1475                                             "%s: skip BDR, past eh deadline\n",
1476                                              current->comm));
1477                         break;
1478                 }
1479                 bdr_scmd = NULL;
1480                 list_for_each_entry(scmd, work_q, eh_entry)
1481                         if (scmd->device == sdev) {
1482                                 bdr_scmd = scmd;
1483                                 break;
1484                         }
1485
1486                 if (!bdr_scmd)
1487                         continue;
1488
1489                 SCSI_LOG_ERROR_RECOVERY(3,
1490                         sdev_printk(KERN_INFO, sdev,
1491                                      "%s: Sending BDR\n", current->comm));
1492                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1493                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1494                         if (!scsi_device_online(sdev) ||
1495                             rtn == FAST_IO_FAIL ||
1496                             !scsi_eh_tur(bdr_scmd)) {
1497                                 list_for_each_entry_safe(scmd, next,
1498                                                          work_q, eh_entry) {
1499                                         if (scmd->device == sdev &&
1500                                             scsi_eh_action(scmd, rtn) != FAILED)
1501                                                 scsi_eh_finish_cmd(scmd,
1502                                                                    done_q);
1503                                 }
1504                         }
1505                 } else {
1506                         SCSI_LOG_ERROR_RECOVERY(3,
1507                                 sdev_printk(KERN_INFO, sdev,
1508                                             "%s: BDR failed\n", current->comm));
1509                 }
1510         }
1511
1512         return list_empty(work_q);
1513 }
1514
1515 /**
1516  * scsi_eh_target_reset - send target reset if needed
1517  * @shost:      scsi host being recovered.
1518  * @work_q:     &list_head for pending commands.
1519  * @done_q:     &list_head for processed commands.
1520  *
1521  * Notes:
1522  *    Try a target reset.
1523  */
1524 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1525                                 struct list_head *work_q,
1526                                 struct list_head *done_q)
1527 {
1528         LIST_HEAD(tmp_list);
1529         LIST_HEAD(check_list);
1530
1531         list_splice_init(work_q, &tmp_list);
1532
1533         while (!list_empty(&tmp_list)) {
1534                 struct scsi_cmnd *next, *scmd;
1535                 int rtn;
1536                 unsigned int id;
1537
1538                 if (scsi_host_eh_past_deadline(shost)) {
1539                         /* push back on work queue for further processing */
1540                         list_splice_init(&check_list, work_q);
1541                         list_splice_init(&tmp_list, work_q);
1542                         SCSI_LOG_ERROR_RECOVERY(3,
1543                                 shost_printk(KERN_INFO, shost,
1544                                             "%s: Skip target reset, past eh deadline\n",
1545                                              current->comm));
1546                         return list_empty(work_q);
1547                 }
1548
1549                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1550                 id = scmd_id(scmd);
1551
1552                 SCSI_LOG_ERROR_RECOVERY(3,
1553                         shost_printk(KERN_INFO, shost,
1554                                      "%s: Sending target reset to target %d\n",
1555                                      current->comm, id));
1556                 rtn = scsi_try_target_reset(scmd);
1557                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1558                         SCSI_LOG_ERROR_RECOVERY(3,
1559                                 shost_printk(KERN_INFO, shost,
1560                                              "%s: Target reset failed"
1561                                              " target: %d\n",
1562                                              current->comm, id));
1563                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1564                         if (scmd_id(scmd) != id)
1565                                 continue;
1566
1567                         if (rtn == SUCCESS)
1568                                 list_move_tail(&scmd->eh_entry, &check_list);
1569                         else if (rtn == FAST_IO_FAIL)
1570                                 scsi_eh_finish_cmd(scmd, done_q);
1571                         else
1572                                 /* push back on work queue for further processing */
1573                                 list_move(&scmd->eh_entry, work_q);
1574                 }
1575         }
1576
1577         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1578 }
1579
1580 /**
1581  * scsi_eh_bus_reset - send a bus reset
1582  * @shost:      &scsi host being recovered.
1583  * @work_q:     &list_head for pending commands.
1584  * @done_q:     &list_head for processed commands.
1585  */
1586 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1587                              struct list_head *work_q,
1588                              struct list_head *done_q)
1589 {
1590         struct scsi_cmnd *scmd, *chan_scmd, *next;
1591         LIST_HEAD(check_list);
1592         unsigned int channel;
1593         int rtn;
1594
1595         /*
1596          * we really want to loop over the various channels, and do this on
1597          * a channel by channel basis.  we should also check to see if any
1598          * of the failed commands are on soft_reset devices, and if so, skip
1599          * the reset.
1600          */
1601
1602         for (channel = 0; channel <= shost->max_channel; channel++) {
1603                 if (scsi_host_eh_past_deadline(shost)) {
1604                         list_splice_init(&check_list, work_q);
1605                         SCSI_LOG_ERROR_RECOVERY(3,
1606                                 shost_printk(KERN_INFO, shost,
1607                                             "%s: skip BRST, past eh deadline\n",
1608                                              current->comm));
1609                         return list_empty(work_q);
1610                 }
1611
1612                 chan_scmd = NULL;
1613                 list_for_each_entry(scmd, work_q, eh_entry) {
1614                         if (channel == scmd_channel(scmd)) {
1615                                 chan_scmd = scmd;
1616                                 break;
1617                                 /*
1618                                  * FIXME add back in some support for
1619                                  * soft_reset devices.
1620                                  */
1621                         }
1622                 }
1623
1624                 if (!chan_scmd)
1625                         continue;
1626                 SCSI_LOG_ERROR_RECOVERY(3,
1627                         shost_printk(KERN_INFO, shost,
1628                                      "%s: Sending BRST chan: %d\n",
1629                                      current->comm, channel));
1630                 rtn = scsi_try_bus_reset(chan_scmd);
1631                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1632                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1633                                 if (channel == scmd_channel(scmd)) {
1634                                         if (rtn == FAST_IO_FAIL)
1635                                                 scsi_eh_finish_cmd(scmd,
1636                                                                    done_q);
1637                                         else
1638                                                 list_move_tail(&scmd->eh_entry,
1639                                                                &check_list);
1640                                 }
1641                         }
1642                 } else {
1643                         SCSI_LOG_ERROR_RECOVERY(3,
1644                                 shost_printk(KERN_INFO, shost,
1645                                              "%s: BRST failed chan: %d\n",
1646                                              current->comm, channel));
1647                 }
1648         }
1649         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1650 }
1651
1652 /**
1653  * scsi_eh_host_reset - send a host reset
1654  * @shost:      host to be reset.
1655  * @work_q:     &list_head for pending commands.
1656  * @done_q:     &list_head for processed commands.
1657  */
1658 static int scsi_eh_host_reset(struct Scsi_Host *shost,
1659                               struct list_head *work_q,
1660                               struct list_head *done_q)
1661 {
1662         struct scsi_cmnd *scmd, *next;
1663         LIST_HEAD(check_list);
1664         int rtn;
1665
1666         if (!list_empty(work_q)) {
1667                 scmd = list_entry(work_q->next,
1668                                   struct scsi_cmnd, eh_entry);
1669
1670                 SCSI_LOG_ERROR_RECOVERY(3,
1671                         shost_printk(KERN_INFO, shost,
1672                                      "%s: Sending HRST\n",
1673                                      current->comm));
1674
1675                 rtn = scsi_try_host_reset(scmd);
1676                 if (rtn == SUCCESS) {
1677                         list_splice_init(work_q, &check_list);
1678                 } else if (rtn == FAST_IO_FAIL) {
1679                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1680                                         scsi_eh_finish_cmd(scmd, done_q);
1681                         }
1682                 } else {
1683                         SCSI_LOG_ERROR_RECOVERY(3,
1684                                 shost_printk(KERN_INFO, shost,
1685                                              "%s: HRST failed\n",
1686                                              current->comm));
1687                 }
1688         }
1689         return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1690 }
1691
1692 /**
1693  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1694  * @work_q:     &list_head for pending commands.
1695  * @done_q:     &list_head for processed commands.
1696  */
1697 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1698                                   struct list_head *done_q)
1699 {
1700         struct scsi_cmnd *scmd, *next;
1701
1702         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1703                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1704                             "not ready after error recovery\n");
1705                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1706                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1707                         /*
1708                          * FIXME: Handle lost cmds.
1709                          */
1710                 }
1711                 scsi_eh_finish_cmd(scmd, done_q);
1712         }
1713         return;
1714 }
1715
1716 /**
1717  * scsi_noretry_cmd - determine if command should be failed fast
1718  * @scmd:       SCSI cmd to examine.
1719  */
1720 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1721 {
1722         switch (host_byte(scmd->result)) {
1723         case DID_OK:
1724                 break;
1725         case DID_TIME_OUT:
1726                 goto check_type;
1727         case DID_BUS_BUSY:
1728                 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1729         case DID_PARITY:
1730                 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1731         case DID_ERROR:
1732                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1733                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1734                         return 0;
1735                 /* fall through */
1736         case DID_SOFT_ERROR:
1737                 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1738         }
1739
1740         if (status_byte(scmd->result) != CHECK_CONDITION)
1741                 return 0;
1742
1743 check_type:
1744         /*
1745          * assume caller has checked sense and determined
1746          * the check condition was retryable.
1747          */
1748         if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1749             scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1750                 return 1;
1751         else
1752                 return 0;
1753 }
1754
1755 /**
1756  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1757  * @scmd:       SCSI cmd to examine.
1758  *
1759  * Notes:
1760  *    This is *only* called when we are examining the status after sending
1761  *    out the actual data command.  any commands that are queued for error
1762  *    recovery (e.g. test_unit_ready) do *not* come through here.
1763  *
1764  *    When this routine returns failed, it means the error handler thread
1765  *    is woken.  In cases where the error code indicates an error that
1766  *    doesn't require the error handler read (i.e. we don't need to
1767  *    abort/reset), this function should return SUCCESS.
1768  */
1769 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1770 {
1771         int rtn;
1772
1773         /*
1774          * if the device is offline, then we clearly just pass the result back
1775          * up to the top level.
1776          */
1777         if (!scsi_device_online(scmd->device)) {
1778                 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1779                         "%s: device offline - report as SUCCESS\n", __func__));
1780                 return SUCCESS;
1781         }
1782
1783         /*
1784          * first check the host byte, to see if there is anything in there
1785          * that would indicate what we need to do.
1786          */
1787         switch (host_byte(scmd->result)) {
1788         case DID_PASSTHROUGH:
1789                 /*
1790                  * no matter what, pass this through to the upper layer.
1791                  * nuke this special code so that it looks like we are saying
1792                  * did_ok.
1793                  */
1794                 scmd->result &= 0xff00ffff;
1795                 return SUCCESS;
1796         case DID_OK:
1797                 /*
1798                  * looks good.  drop through, and check the next byte.
1799                  */
1800                 break;
1801         case DID_ABORT:
1802                 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1803                         set_host_byte(scmd, DID_TIME_OUT);
1804                         return SUCCESS;
1805                 }
1806         case DID_NO_CONNECT:
1807         case DID_BAD_TARGET:
1808                 /*
1809                  * note - this means that we just report the status back
1810                  * to the top level driver, not that we actually think
1811                  * that it indicates SUCCESS.
1812                  */
1813                 return SUCCESS;
1814                 /*
1815                  * when the low level driver returns did_soft_error,
1816                  * it is responsible for keeping an internal retry counter
1817                  * in order to avoid endless loops (db)
1818                  *
1819                  * actually this is a bug in this function here.  we should
1820                  * be mindful of the maximum number of retries specified
1821                  * and not get stuck in a loop.
1822                  */
1823         case DID_SOFT_ERROR:
1824                 goto maybe_retry;
1825         case DID_IMM_RETRY:
1826                 return NEEDS_RETRY;
1827
1828         case DID_REQUEUE:
1829                 return ADD_TO_MLQUEUE;
1830         case DID_TRANSPORT_DISRUPTED:
1831                 /*
1832                  * LLD/transport was disrupted during processing of the IO.
1833                  * The transport class is now blocked/blocking,
1834                  * and the transport will decide what to do with the IO
1835                  * based on its timers and recovery capablilities if
1836                  * there are enough retries.
1837                  */
1838                 goto maybe_retry;
1839         case DID_TRANSPORT_FAILFAST:
1840                 /*
1841                  * The transport decided to failfast the IO (most likely
1842                  * the fast io fail tmo fired), so send IO directly upwards.
1843                  */
1844                 return SUCCESS;
1845         case DID_ERROR:
1846                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1847                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1848                         /*
1849                          * execute reservation conflict processing code
1850                          * lower down
1851                          */
1852                         break;
1853                 /* fallthrough */
1854         case DID_BUS_BUSY:
1855         case DID_PARITY:
1856                 goto maybe_retry;
1857         case DID_TIME_OUT:
1858                 /*
1859                  * when we scan the bus, we get timeout messages for
1860                  * these commands if there is no device available.
1861                  * other hosts report did_no_connect for the same thing.
1862                  */
1863                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1864                      scmd->cmnd[0] == INQUIRY)) {
1865                         return SUCCESS;
1866                 } else {
1867                         return FAILED;
1868                 }
1869         case DID_RESET:
1870                 return SUCCESS;
1871         default:
1872                 return FAILED;
1873         }
1874
1875         /*
1876          * next, check the message byte.
1877          */
1878         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1879                 return FAILED;
1880
1881         /*
1882          * check the status byte to see if this indicates anything special.
1883          */
1884         switch (status_byte(scmd->result)) {
1885         case QUEUE_FULL:
1886                 scsi_handle_queue_full(scmd->device);
1887                 /*
1888                  * the case of trying to send too many commands to a
1889                  * tagged queueing device.
1890                  */
1891         case BUSY:
1892                 /*
1893                  * device can't talk to us at the moment.  Should only
1894                  * occur (SAM-3) when the task queue is empty, so will cause
1895                  * the empty queue handling to trigger a stall in the
1896                  * device.
1897                  */
1898                 return ADD_TO_MLQUEUE;
1899         case GOOD:
1900                 if (scmd->cmnd[0] == REPORT_LUNS)
1901                         scmd->device->sdev_target->expecting_lun_change = 0;
1902                 scsi_handle_queue_ramp_up(scmd->device);
1903         case COMMAND_TERMINATED:
1904                 return SUCCESS;
1905         case TASK_ABORTED:
1906                 goto maybe_retry;
1907         case CHECK_CONDITION:
1908                 rtn = scsi_check_sense(scmd);
1909                 if (rtn == NEEDS_RETRY)
1910                         goto maybe_retry;
1911                 /* if rtn == FAILED, we have no sense information;
1912                  * returning FAILED will wake the error handler thread
1913                  * to collect the sense and redo the decide
1914                  * disposition */
1915                 return rtn;
1916         case CONDITION_GOOD:
1917         case INTERMEDIATE_GOOD:
1918         case INTERMEDIATE_C_GOOD:
1919         case ACA_ACTIVE:
1920                 /*
1921                  * who knows?  FIXME(eric)
1922                  */
1923                 return SUCCESS;
1924
1925         case RESERVATION_CONFLICT:
1926                 sdev_printk(KERN_INFO, scmd->device,
1927                             "reservation conflict\n");
1928                 set_host_byte(scmd, DID_NEXUS_FAILURE);
1929                 return SUCCESS; /* causes immediate i/o error */
1930         default:
1931                 return FAILED;
1932         }
1933         return FAILED;
1934
1935       maybe_retry:
1936
1937         /* we requeue for retry because the error was retryable, and
1938          * the request was not marked fast fail.  Note that above,
1939          * even if the request is marked fast fail, we still requeue
1940          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1941         if ((++scmd->retries) <= scmd->allowed
1942             && !scsi_noretry_cmd(scmd)) {
1943                 return NEEDS_RETRY;
1944         } else {
1945                 /*
1946                  * no more retries - report this one back to upper level.
1947                  */
1948                 return SUCCESS;
1949         }
1950 }
1951
1952 static void eh_lock_door_done(struct request *req, int uptodate)
1953 {
1954         __blk_put_request(req->q, req);
1955 }
1956
1957 /**
1958  * scsi_eh_lock_door - Prevent medium removal for the specified device
1959  * @sdev:       SCSI device to prevent medium removal
1960  *
1961  * Locking:
1962  *      We must be called from process context.
1963  *
1964  * Notes:
1965  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1966  *      head of the devices request queue, and continue.
1967  */
1968 static void scsi_eh_lock_door(struct scsi_device *sdev)
1969 {
1970         struct request *req;
1971
1972         /*
1973          * blk_get_request with GFP_KERNEL (__GFP_RECLAIM) sleeps until a
1974          * request becomes available
1975          */
1976         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1977         if (IS_ERR(req))
1978                 return;
1979
1980         blk_rq_set_block_pc(req);
1981
1982         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1983         req->cmd[1] = 0;
1984         req->cmd[2] = 0;
1985         req->cmd[3] = 0;
1986         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1987         req->cmd[5] = 0;
1988
1989         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1990
1991         req->cmd_flags |= REQ_QUIET;
1992         req->timeout = 10 * HZ;
1993         req->retries = 5;
1994
1995         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1996 }
1997
1998 /**
1999  * scsi_restart_operations - restart io operations to the specified host.
2000  * @shost:      Host we are restarting.
2001  *
2002  * Notes:
2003  *    When we entered the error handler, we blocked all further i/o to
2004  *    this device.  we need to 'reverse' this process.
2005  */
2006 static void scsi_restart_operations(struct Scsi_Host *shost)
2007 {
2008         struct scsi_device *sdev;
2009         unsigned long flags;
2010
2011         /*
2012          * If the door was locked, we need to insert a door lock request
2013          * onto the head of the SCSI request queue for the device.  There
2014          * is no point trying to lock the door of an off-line device.
2015          */
2016         shost_for_each_device(sdev, shost) {
2017                 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2018                         scsi_eh_lock_door(sdev);
2019                         sdev->was_reset = 0;
2020                 }
2021         }
2022
2023         /*
2024          * next free up anything directly waiting upon the host.  this
2025          * will be requests for character device operations, and also for
2026          * ioctls to queued block devices.
2027          */
2028         SCSI_LOG_ERROR_RECOVERY(3,
2029                 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2030
2031         spin_lock_irqsave(shost->host_lock, flags);
2032         if (scsi_host_set_state(shost, SHOST_RUNNING))
2033                 if (scsi_host_set_state(shost, SHOST_CANCEL))
2034                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2035         spin_unlock_irqrestore(shost->host_lock, flags);
2036
2037         wake_up(&shost->host_wait);
2038
2039         /*
2040          * finally we need to re-initiate requests that may be pending.  we will
2041          * have had everything blocked while error handling is taking place, and
2042          * now that error recovery is done, we will need to ensure that these
2043          * requests are started.
2044          */
2045         scsi_run_host_queues(shost);
2046
2047         /*
2048          * if eh is active and host_eh_scheduled is pending we need to re-run
2049          * recovery.  we do this check after scsi_run_host_queues() to allow
2050          * everything pent up since the last eh run a chance to make forward
2051          * progress before we sync again.  Either we'll immediately re-run
2052          * recovery or scsi_device_unbusy() will wake us again when these
2053          * pending commands complete.
2054          */
2055         spin_lock_irqsave(shost->host_lock, flags);
2056         if (shost->host_eh_scheduled)
2057                 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2058                         WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2059         spin_unlock_irqrestore(shost->host_lock, flags);
2060 }
2061
2062 /**
2063  * scsi_eh_ready_devs - check device ready state and recover if not.
2064  * @shost:      host to be recovered.
2065  * @work_q:     &list_head for pending commands.
2066  * @done_q:     &list_head for processed commands.
2067  */
2068 void scsi_eh_ready_devs(struct Scsi_Host *shost,
2069                         struct list_head *work_q,
2070                         struct list_head *done_q)
2071 {
2072         if (!scsi_eh_stu(shost, work_q, done_q))
2073                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2074                         if (!scsi_eh_target_reset(shost, work_q, done_q))
2075                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2076                                         if (!scsi_eh_host_reset(shost, work_q, done_q))
2077                                                 scsi_eh_offline_sdevs(work_q,
2078                                                                       done_q);
2079 }
2080 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2081
2082 /**
2083  * scsi_eh_flush_done_q - finish processed commands or retry them.
2084  * @done_q:     list_head of processed commands.
2085  */
2086 void scsi_eh_flush_done_q(struct list_head *done_q)
2087 {
2088         struct scsi_cmnd *scmd, *next;
2089
2090         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2091                 list_del_init(&scmd->eh_entry);
2092                 if (scsi_device_online(scmd->device) &&
2093                     !scsi_noretry_cmd(scmd) &&
2094                     (++scmd->retries <= scmd->allowed)) {
2095                         SCSI_LOG_ERROR_RECOVERY(3,
2096                                 scmd_printk(KERN_INFO, scmd,
2097                                              "%s: flush retry cmd\n",
2098                                              current->comm));
2099                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2100                 } else {
2101                         /*
2102                          * If just we got sense for the device (called
2103                          * scsi_eh_get_sense), scmd->result is already
2104                          * set, do not set DRIVER_TIMEOUT.
2105                          */
2106                         if (!scmd->result)
2107                                 scmd->result |= (DRIVER_TIMEOUT << 24);
2108                         SCSI_LOG_ERROR_RECOVERY(3,
2109                                 scmd_printk(KERN_INFO, scmd,
2110                                              "%s: flush finish cmd\n",
2111                                              current->comm));
2112                         scsi_finish_command(scmd);
2113                 }
2114         }
2115 }
2116 EXPORT_SYMBOL(scsi_eh_flush_done_q);
2117
2118 /**
2119  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2120  * @shost:      Host to unjam.
2121  *
2122  * Notes:
2123  *    When we come in here, we *know* that all commands on the bus have
2124  *    either completed, failed or timed out.  we also know that no further
2125  *    commands are being sent to the host, so things are relatively quiet
2126  *    and we have freedom to fiddle with things as we wish.
2127  *
2128  *    This is only the *default* implementation.  it is possible for
2129  *    individual drivers to supply their own version of this function, and
2130  *    if the maintainer wishes to do this, it is strongly suggested that
2131  *    this function be taken as a template and modified.  this function
2132  *    was designed to correctly handle problems for about 95% of the
2133  *    different cases out there, and it should always provide at least a
2134  *    reasonable amount of error recovery.
2135  *
2136  *    Any command marked 'failed' or 'timeout' must eventually have
2137  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
2138  *    here, so when we restart the host after we return it should have an
2139  *    empty queue.
2140  */
2141 static void scsi_unjam_host(struct Scsi_Host *shost)
2142 {
2143         unsigned long flags;
2144         LIST_HEAD(eh_work_q);
2145         LIST_HEAD(eh_done_q);
2146
2147         spin_lock_irqsave(shost->host_lock, flags);
2148         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2149         spin_unlock_irqrestore(shost->host_lock, flags);
2150
2151         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2152
2153         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2154                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
2155                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2156
2157         spin_lock_irqsave(shost->host_lock, flags);
2158         if (shost->eh_deadline != -1)
2159                 shost->last_reset = 0;
2160         spin_unlock_irqrestore(shost->host_lock, flags);
2161         scsi_eh_flush_done_q(&eh_done_q);
2162 }
2163
2164 /**
2165  * scsi_error_handler - SCSI error handler thread
2166  * @data:       Host for which we are running.
2167  *
2168  * Notes:
2169  *    This is the main error handling loop.  This is run as a kernel thread
2170  *    for every SCSI host and handles all error handling activity.
2171  */
2172 int scsi_error_handler(void *data)
2173 {
2174         struct Scsi_Host *shost = data;
2175
2176         /*
2177          * We use TASK_INTERRUPTIBLE so that the thread is not
2178          * counted against the load average as a running process.
2179          * We never actually get interrupted because kthread_run
2180          * disables signal delivery for the created thread.
2181          */
2182         while (true) {
2183                 /*
2184                  * The sequence in kthread_stop() sets the stop flag first
2185                  * then wakes the process.  To avoid missed wakeups, the task
2186                  * should always be in a non running state before the stop
2187                  * flag is checked
2188                  */
2189                 set_current_state(TASK_INTERRUPTIBLE);
2190                 if (kthread_should_stop())
2191                         break;
2192
2193                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2194                     shost->host_failed != atomic_read(&shost->host_busy)) {
2195                         SCSI_LOG_ERROR_RECOVERY(1,
2196                                 shost_printk(KERN_INFO, shost,
2197                                              "scsi_eh_%d: sleeping\n",
2198                                              shost->host_no));
2199                         schedule();
2200                         continue;
2201                 }
2202
2203                 __set_current_state(TASK_RUNNING);
2204                 SCSI_LOG_ERROR_RECOVERY(1,
2205                         shost_printk(KERN_INFO, shost,
2206                                      "scsi_eh_%d: waking up %d/%d/%d\n",
2207                                      shost->host_no, shost->host_eh_scheduled,
2208                                      shost->host_failed,
2209                                      atomic_read(&shost->host_busy)));
2210
2211                 /*
2212                  * We have a host that is failing for some reason.  Figure out
2213                  * what we need to do to get it up and online again (if we can).
2214                  * If we fail, we end up taking the thing offline.
2215                  */
2216                 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2217                         SCSI_LOG_ERROR_RECOVERY(1,
2218                                 shost_printk(KERN_ERR, shost,
2219                                              "scsi_eh_%d: unable to autoresume\n",
2220                                              shost->host_no));
2221                         continue;
2222                 }
2223
2224                 if (shost->transportt->eh_strategy_handler)
2225                         shost->transportt->eh_strategy_handler(shost);
2226                 else
2227                         scsi_unjam_host(shost);
2228
2229                 /*
2230                  * Note - if the above fails completely, the action is to take
2231                  * individual devices offline and flush the queue of any
2232                  * outstanding requests that may have been pending.  When we
2233                  * restart, we restart any I/O to any other devices on the bus
2234                  * which are still online.
2235                  */
2236                 scsi_restart_operations(shost);
2237                 if (!shost->eh_noresume)
2238                         scsi_autopm_put_host(shost);
2239         }
2240         __set_current_state(TASK_RUNNING);
2241
2242         SCSI_LOG_ERROR_RECOVERY(1,
2243                 shost_printk(KERN_INFO, shost,
2244                              "Error handler scsi_eh_%d exiting\n",
2245                              shost->host_no));
2246         shost->ehandler = NULL;
2247         return 0;
2248 }
2249
2250 /*
2251  * Function:    scsi_report_bus_reset()
2252  *
2253  * Purpose:     Utility function used by low-level drivers to report that
2254  *              they have observed a bus reset on the bus being handled.
2255  *
2256  * Arguments:   shost       - Host in question
2257  *              channel     - channel on which reset was observed.
2258  *
2259  * Returns:     Nothing
2260  *
2261  * Lock status: Host lock must be held.
2262  *
2263  * Notes:       This only needs to be called if the reset is one which
2264  *              originates from an unknown location.  Resets originated
2265  *              by the mid-level itself don't need to call this, but there
2266  *              should be no harm.
2267  *
2268  *              The main purpose of this is to make sure that a CHECK_CONDITION
2269  *              is properly treated.
2270  */
2271 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2272 {
2273         struct scsi_device *sdev;
2274
2275         __shost_for_each_device(sdev, shost) {
2276                 if (channel == sdev_channel(sdev))
2277                         __scsi_report_device_reset(sdev, NULL);
2278         }
2279 }
2280 EXPORT_SYMBOL(scsi_report_bus_reset);
2281
2282 /*
2283  * Function:    scsi_report_device_reset()
2284  *
2285  * Purpose:     Utility function used by low-level drivers to report that
2286  *              they have observed a device reset on the device being handled.
2287  *
2288  * Arguments:   shost       - Host in question
2289  *              channel     - channel on which reset was observed
2290  *              target      - target on which reset was observed
2291  *
2292  * Returns:     Nothing
2293  *
2294  * Lock status: Host lock must be held
2295  *
2296  * Notes:       This only needs to be called if the reset is one which
2297  *              originates from an unknown location.  Resets originated
2298  *              by the mid-level itself don't need to call this, but there
2299  *              should be no harm.
2300  *
2301  *              The main purpose of this is to make sure that a CHECK_CONDITION
2302  *              is properly treated.
2303  */
2304 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2305 {
2306         struct scsi_device *sdev;
2307
2308         __shost_for_each_device(sdev, shost) {
2309                 if (channel == sdev_channel(sdev) &&
2310                     target == sdev_id(sdev))
2311                         __scsi_report_device_reset(sdev, NULL);
2312         }
2313 }
2314 EXPORT_SYMBOL(scsi_report_device_reset);
2315
2316 static void
2317 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2318 {
2319 }
2320
2321 /**
2322  * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2323  * @dev:        scsi_device to operate on
2324  * @arg:        reset type (see sg.h)
2325  */
2326 int
2327 scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2328 {
2329         struct scsi_cmnd *scmd;
2330         struct Scsi_Host *shost = dev->host;
2331         struct request req;
2332         unsigned long flags;
2333         int error = 0, rtn, val;
2334
2335         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2336                 return -EACCES;
2337
2338         error = get_user(val, arg);
2339         if (error)
2340                 return error;
2341
2342         if (scsi_autopm_get_host(shost) < 0)
2343                 return -EIO;
2344
2345         error = -EIO;
2346         scmd = scsi_get_command(dev, GFP_KERNEL);
2347         if (!scmd)
2348                 goto out_put_autopm_host;
2349
2350         blk_rq_init(NULL, &req);
2351         scmd->request = &req;
2352
2353         scmd->cmnd = req.cmd;
2354
2355         scmd->scsi_done         = scsi_reset_provider_done_command;
2356         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2357
2358         scmd->cmd_len                   = 0;
2359
2360         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
2361
2362         spin_lock_irqsave(shost->host_lock, flags);
2363         shost->tmf_in_progress = 1;
2364         spin_unlock_irqrestore(shost->host_lock, flags);
2365
2366         switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2367         case SG_SCSI_RESET_NOTHING:
2368                 rtn = SUCCESS;
2369                 break;
2370         case SG_SCSI_RESET_DEVICE:
2371                 rtn = scsi_try_bus_device_reset(scmd);
2372                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2373                         break;
2374                 /* FALLTHROUGH */
2375         case SG_SCSI_RESET_TARGET:
2376                 rtn = scsi_try_target_reset(scmd);
2377                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2378                         break;
2379                 /* FALLTHROUGH */
2380         case SG_SCSI_RESET_BUS:
2381                 rtn = scsi_try_bus_reset(scmd);
2382                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2383                         break;
2384                 /* FALLTHROUGH */
2385         case SG_SCSI_RESET_HOST:
2386                 rtn = scsi_try_host_reset(scmd);
2387                 if (rtn == SUCCESS)
2388                         break;
2389         default:
2390                 /* FALLTHROUGH */
2391                 rtn = FAILED;
2392                 break;
2393         }
2394
2395         error = (rtn == SUCCESS) ? 0 : -EIO;
2396
2397         spin_lock_irqsave(shost->host_lock, flags);
2398         shost->tmf_in_progress = 0;
2399         spin_unlock_irqrestore(shost->host_lock, flags);
2400
2401         /*
2402          * be sure to wake up anyone who was sleeping or had their queue
2403          * suspended while we performed the TMF.
2404          */
2405         SCSI_LOG_ERROR_RECOVERY(3,
2406                 shost_printk(KERN_INFO, shost,
2407                              "waking up host to restart after TMF\n"));
2408
2409         wake_up(&shost->host_wait);
2410         scsi_run_host_queues(shost);
2411
2412         scsi_put_command(scmd);
2413
2414 out_put_autopm_host:
2415         scsi_autopm_put_host(shost);
2416         return error;
2417 }
2418 EXPORT_SYMBOL(scsi_ioctl_reset);
2419
2420 bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2421                                   struct scsi_sense_hdr *sshdr)
2422 {
2423         return scsi_normalize_sense(cmd->sense_buffer,
2424                         SCSI_SENSE_BUFFERSIZE, sshdr);
2425 }
2426 EXPORT_SYMBOL(scsi_command_normalize_sense);
2427
2428 /**
2429  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2430  * @sense_buffer:       byte array of sense data
2431  * @sb_len:             number of valid bytes in sense_buffer
2432  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2433  *                      field will be placed if found.
2434  *
2435  * Return value:
2436  *      1 if information field found, 0 if not found.
2437  */
2438 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2439                             u64 * info_out)
2440 {
2441         int j;
2442         const u8 * ucp;
2443         u64 ull;
2444
2445         if (sb_len < 7)
2446                 return 0;
2447         switch (sense_buffer[0] & 0x7f) {
2448         case 0x70:
2449         case 0x71:
2450                 if (sense_buffer[0] & 0x80) {
2451                         *info_out = (sense_buffer[3] << 24) +
2452                                     (sense_buffer[4] << 16) +
2453                                     (sense_buffer[5] << 8) + sense_buffer[6];
2454                         return 1;
2455                 } else
2456                         return 0;
2457         case 0x72:
2458         case 0x73:
2459                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2460                                            0 /* info desc */);
2461                 if (ucp && (0xa == ucp[1])) {
2462                         ull = 0;
2463                         for (j = 0; j < 8; ++j) {
2464                                 if (j > 0)
2465                                         ull <<= 8;
2466                                 ull |= ucp[4 + j];
2467                         }
2468                         *info_out = ull;
2469                         return 1;
2470                 } else
2471                         return 0;
2472         default:
2473                 return 0;
2474         }
2475 }
2476 EXPORT_SYMBOL(scsi_get_sense_info_fld);