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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
49static 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
58static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
59static int scsi_try_to_abort_cmd(struct scsi_host_template *,
60 struct scsi_cmnd *);
61
62/* called with shost->host_lock held */
63void 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 */
79void 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}
93EXPORT_SYMBOL_GPL(scsi_schedule_eh);
94
95static 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 */
118void
119scmd_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 */
180static int
181scsi_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 */
231int 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 */
270enum 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 */
311int 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}
324EXPORT_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 */
332static 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 */
377static 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 */
388static 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 */
455static 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
606static 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
638static 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 */
669static 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 */
733static 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 */
749static 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 */
779static 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
805static 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 */
821static 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 */
852static 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 */
883static 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
892static 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 */
915void 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}
976EXPORT_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 */
985void 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}
999EXPORT_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 */
1015static 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
1026retry:
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 */
1101static 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
1106static 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 */
1128void 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}
1134EXPORT_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 */
1156int 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}
1221EXPORT_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 */
1230static 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
1235retry_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 **/
1267static 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 */
1322static 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 */
1371static 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 */
1398static 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 */
1463static 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 */
1524static 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 */
1586static 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 */
1658static 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 */
1697static 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 */
1720int 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
1743check_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 */
1769int 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
1952static 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 */
1968static 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 */
2006static 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 */
2068void 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}
2080EXPORT_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 */
2086void 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}
2116EXPORT_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 */
2141static 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 */
2172int 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 */
2271void 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}
2280EXPORT_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 */
2304void 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}
2314EXPORT_SYMBOL(scsi_report_device_reset);
2315
2316static void
2317scsi_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 */
2326int
2327scsi_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
2414out_put_autopm_host:
2415 scsi_autopm_put_host(shost);
2416 return error;
2417}
2418EXPORT_SYMBOL(scsi_ioctl_reset);
2419
2420bool 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}
2426EXPORT_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 */
2438int 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}
2476EXPORT_SYMBOL(scsi_get_sense_info_fld);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi_error.c Copyright (C) 1997 Eric Youngdale
4 *
5 * SCSI error/timeout handling
6 * Initial versions: Eric Youngdale. Based upon conversations with
7 * Leonard Zubkoff and David Miller at Linux Expo,
8 * ideas originating from all over the place.
9 *
10 * Restructured scsi_unjam_host and associated functions.
11 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
12 *
13 * Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
14 * minor cleanups.
15 * September 30, 2002 Mike Anderson (andmike@us.ibm.com)
16 */
17
18#include <linux/module.h>
19#include <linux/sched.h>
20#include <linux/gfp.h>
21#include <linux/timer.h>
22#include <linux/string.h>
23#include <linux/kernel.h>
24#include <linux/freezer.h>
25#include <linux/kthread.h>
26#include <linux/interrupt.h>
27#include <linux/blkdev.h>
28#include <linux/delay.h>
29#include <linux/jiffies.h>
30
31#include <scsi/scsi.h>
32#include <scsi/scsi_cmnd.h>
33#include <scsi/scsi_dbg.h>
34#include <scsi/scsi_device.h>
35#include <scsi/scsi_driver.h>
36#include <scsi/scsi_eh.h>
37#include <scsi/scsi_common.h>
38#include <scsi/scsi_transport.h>
39#include <scsi/scsi_host.h>
40#include <scsi/scsi_ioctl.h>
41#include <scsi/scsi_dh.h>
42#include <scsi/scsi_devinfo.h>
43#include <scsi/sg.h>
44
45#include "scsi_priv.h"
46#include "scsi_logging.h"
47#include "scsi_transport_api.h"
48
49#include <trace/events/scsi.h>
50
51#include <asm/unaligned.h>
52
53/*
54 * These should *probably* be handled by the host itself.
55 * Since it is allowed to sleep, it probably should.
56 */
57#define BUS_RESET_SETTLE_TIME (10)
58#define HOST_RESET_SETTLE_TIME (10)
59
60static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
61static enum scsi_disposition scsi_try_to_abort_cmd(struct scsi_host_template *,
62 struct scsi_cmnd *);
63
64void scsi_eh_wakeup(struct Scsi_Host *shost)
65{
66 lockdep_assert_held(shost->host_lock);
67
68 if (scsi_host_busy(shost) == shost->host_failed) {
69 trace_scsi_eh_wakeup(shost);
70 wake_up_process(shost->ehandler);
71 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
72 "Waking error handler thread\n"));
73 }
74}
75
76/**
77 * scsi_schedule_eh - schedule EH for SCSI host
78 * @shost: SCSI host to invoke error handling on.
79 *
80 * Schedule SCSI EH without scmd.
81 */
82void scsi_schedule_eh(struct Scsi_Host *shost)
83{
84 unsigned long flags;
85
86 spin_lock_irqsave(shost->host_lock, flags);
87
88 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
89 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
90 shost->host_eh_scheduled++;
91 scsi_eh_wakeup(shost);
92 }
93
94 spin_unlock_irqrestore(shost->host_lock, flags);
95}
96EXPORT_SYMBOL_GPL(scsi_schedule_eh);
97
98static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
99{
100 if (!shost->last_reset || shost->eh_deadline == -1)
101 return 0;
102
103 /*
104 * 32bit accesses are guaranteed to be atomic
105 * (on all supported architectures), so instead
106 * of using a spinlock we can as well double check
107 * if eh_deadline has been set to 'off' during the
108 * time_before call.
109 */
110 if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
111 shost->eh_deadline > -1)
112 return 0;
113
114 return 1;
115}
116
117static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
118{
119 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
120 return true;
121
122 return ++cmd->retries <= cmd->allowed;
123}
124
125static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
126{
127 struct scsi_device *sdev = cmd->device;
128 struct Scsi_Host *host = sdev->host;
129
130 if (host->hostt->eh_should_retry_cmd)
131 return host->hostt->eh_should_retry_cmd(cmd);
132
133 return true;
134}
135
136/**
137 * scmd_eh_abort_handler - Handle command aborts
138 * @work: command to be aborted.
139 *
140 * Note: this function must be called only for a command that has timed out.
141 * Because the block layer marks a request as complete before it calls
142 * scsi_timeout(), a .scsi_done() call from the LLD for a command that has
143 * timed out do not have any effect. Hence it is safe to call
144 * scsi_finish_command() from this function.
145 */
146void
147scmd_eh_abort_handler(struct work_struct *work)
148{
149 struct scsi_cmnd *scmd =
150 container_of(work, struct scsi_cmnd, abort_work.work);
151 struct scsi_device *sdev = scmd->device;
152 struct Scsi_Host *shost = sdev->host;
153 enum scsi_disposition rtn;
154 unsigned long flags;
155
156 if (scsi_host_eh_past_deadline(shost)) {
157 SCSI_LOG_ERROR_RECOVERY(3,
158 scmd_printk(KERN_INFO, scmd,
159 "eh timeout, not aborting\n"));
160 goto out;
161 }
162
163 SCSI_LOG_ERROR_RECOVERY(3,
164 scmd_printk(KERN_INFO, scmd,
165 "aborting command\n"));
166 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
167 if (rtn != SUCCESS) {
168 SCSI_LOG_ERROR_RECOVERY(3,
169 scmd_printk(KERN_INFO, scmd,
170 "cmd abort %s\n",
171 (rtn == FAST_IO_FAIL) ?
172 "not send" : "failed"));
173 goto out;
174 }
175 set_host_byte(scmd, DID_TIME_OUT);
176 if (scsi_host_eh_past_deadline(shost)) {
177 SCSI_LOG_ERROR_RECOVERY(3,
178 scmd_printk(KERN_INFO, scmd,
179 "eh timeout, not retrying "
180 "aborted command\n"));
181 goto out;
182 }
183
184 spin_lock_irqsave(shost->host_lock, flags);
185 list_del_init(&scmd->eh_entry);
186
187 /*
188 * If the abort succeeds, and there is no further
189 * EH action, clear the ->last_reset time.
190 */
191 if (list_empty(&shost->eh_abort_list) &&
192 list_empty(&shost->eh_cmd_q))
193 if (shost->eh_deadline != -1)
194 shost->last_reset = 0;
195
196 spin_unlock_irqrestore(shost->host_lock, flags);
197
198 if (!scsi_noretry_cmd(scmd) &&
199 scsi_cmd_retry_allowed(scmd) &&
200 scsi_eh_should_retry_cmd(scmd)) {
201 SCSI_LOG_ERROR_RECOVERY(3,
202 scmd_printk(KERN_WARNING, scmd,
203 "retry aborted command\n"));
204 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
205 } else {
206 SCSI_LOG_ERROR_RECOVERY(3,
207 scmd_printk(KERN_WARNING, scmd,
208 "finish aborted command\n"));
209 scsi_finish_command(scmd);
210 }
211 return;
212
213out:
214 spin_lock_irqsave(shost->host_lock, flags);
215 list_del_init(&scmd->eh_entry);
216 spin_unlock_irqrestore(shost->host_lock, flags);
217
218 scsi_eh_scmd_add(scmd);
219}
220
221/**
222 * scsi_abort_command - schedule a command abort
223 * @scmd: scmd to abort.
224 *
225 * We only need to abort commands after a command timeout
226 */
227static int
228scsi_abort_command(struct scsi_cmnd *scmd)
229{
230 struct scsi_device *sdev = scmd->device;
231 struct Scsi_Host *shost = sdev->host;
232 unsigned long flags;
233
234 if (!shost->hostt->eh_abort_handler) {
235 /* No abort handler, fail command directly */
236 return FAILED;
237 }
238
239 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
240 /*
241 * Retry after abort failed, escalate to next level.
242 */
243 SCSI_LOG_ERROR_RECOVERY(3,
244 scmd_printk(KERN_INFO, scmd,
245 "previous abort failed\n"));
246 BUG_ON(delayed_work_pending(&scmd->abort_work));
247 return FAILED;
248 }
249
250 spin_lock_irqsave(shost->host_lock, flags);
251 if (shost->eh_deadline != -1 && !shost->last_reset)
252 shost->last_reset = jiffies;
253 BUG_ON(!list_empty(&scmd->eh_entry));
254 list_add_tail(&scmd->eh_entry, &shost->eh_abort_list);
255 spin_unlock_irqrestore(shost->host_lock, flags);
256
257 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
258 SCSI_LOG_ERROR_RECOVERY(3,
259 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
260 queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
261 return SUCCESS;
262}
263
264/**
265 * scsi_eh_reset - call into ->eh_action to reset internal counters
266 * @scmd: scmd to run eh on.
267 *
268 * The scsi driver might be carrying internal state about the
269 * devices, so we need to call into the driver to reset the
270 * internal state once the error handler is started.
271 */
272static void scsi_eh_reset(struct scsi_cmnd *scmd)
273{
274 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
275 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
276 if (sdrv->eh_reset)
277 sdrv->eh_reset(scmd);
278 }
279}
280
281static void scsi_eh_inc_host_failed(struct rcu_head *head)
282{
283 struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
284 struct Scsi_Host *shost = scmd->device->host;
285 unsigned long flags;
286
287 spin_lock_irqsave(shost->host_lock, flags);
288 shost->host_failed++;
289 scsi_eh_wakeup(shost);
290 spin_unlock_irqrestore(shost->host_lock, flags);
291}
292
293/**
294 * scsi_eh_scmd_add - add scsi cmd to error handling.
295 * @scmd: scmd to run eh on.
296 */
297void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
298{
299 struct Scsi_Host *shost = scmd->device->host;
300 unsigned long flags;
301 int ret;
302
303 WARN_ON_ONCE(!shost->ehandler);
304
305 spin_lock_irqsave(shost->host_lock, flags);
306 if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
307 ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
308 WARN_ON_ONCE(ret);
309 }
310 if (shost->eh_deadline != -1 && !shost->last_reset)
311 shost->last_reset = jiffies;
312
313 scsi_eh_reset(scmd);
314 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
315 spin_unlock_irqrestore(shost->host_lock, flags);
316 /*
317 * Ensure that all tasks observe the host state change before the
318 * host_failed change.
319 */
320 call_rcu_hurry(&scmd->rcu, scsi_eh_inc_host_failed);
321}
322
323/**
324 * scsi_timeout - Timeout function for normal scsi commands.
325 * @req: request that is timing out.
326 *
327 * Notes:
328 * We do not need to lock this. There is the potential for a race
329 * only in that the normal completion handling might run, but if the
330 * normal completion function determines that the timer has already
331 * fired, then it mustn't do anything.
332 */
333enum blk_eh_timer_return scsi_timeout(struct request *req)
334{
335 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
336 struct Scsi_Host *host = scmd->device->host;
337
338 trace_scsi_dispatch_cmd_timeout(scmd);
339 scsi_log_completion(scmd, TIMEOUT_ERROR);
340
341 atomic_inc(&scmd->device->iotmo_cnt);
342 if (host->eh_deadline != -1 && !host->last_reset)
343 host->last_reset = jiffies;
344
345 if (host->hostt->eh_timed_out) {
346 switch (host->hostt->eh_timed_out(scmd)) {
347 case SCSI_EH_DONE:
348 return BLK_EH_DONE;
349 case SCSI_EH_RESET_TIMER:
350 return BLK_EH_RESET_TIMER;
351 case SCSI_EH_NOT_HANDLED:
352 break;
353 }
354 }
355
356 /*
357 * If scsi_done() has already set SCMD_STATE_COMPLETE, do not modify
358 * *scmd.
359 */
360 if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
361 return BLK_EH_DONE;
362 atomic_inc(&scmd->device->iodone_cnt);
363 if (scsi_abort_command(scmd) != SUCCESS) {
364 set_host_byte(scmd, DID_TIME_OUT);
365 scsi_eh_scmd_add(scmd);
366 }
367
368 return BLK_EH_DONE;
369}
370
371/**
372 * scsi_block_when_processing_errors - Prevent cmds from being queued.
373 * @sdev: Device on which we are performing recovery.
374 *
375 * Description:
376 * We block until the host is out of error recovery, and then check to
377 * see whether the host or the device is offline.
378 *
379 * Return value:
380 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
381 */
382int scsi_block_when_processing_errors(struct scsi_device *sdev)
383{
384 int online;
385
386 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
387
388 online = scsi_device_online(sdev);
389
390 return online;
391}
392EXPORT_SYMBOL(scsi_block_when_processing_errors);
393
394#ifdef CONFIG_SCSI_LOGGING
395/**
396 * scsi_eh_prt_fail_stats - Log info on failures.
397 * @shost: scsi host being recovered.
398 * @work_q: Queue of scsi cmds to process.
399 */
400static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
401 struct list_head *work_q)
402{
403 struct scsi_cmnd *scmd;
404 struct scsi_device *sdev;
405 int total_failures = 0;
406 int cmd_failed = 0;
407 int cmd_cancel = 0;
408 int devices_failed = 0;
409
410 shost_for_each_device(sdev, shost) {
411 list_for_each_entry(scmd, work_q, eh_entry) {
412 if (scmd->device == sdev) {
413 ++total_failures;
414 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
415 ++cmd_cancel;
416 else
417 ++cmd_failed;
418 }
419 }
420
421 if (cmd_cancel || cmd_failed) {
422 SCSI_LOG_ERROR_RECOVERY(3,
423 shost_printk(KERN_INFO, shost,
424 "%s: cmds failed: %d, cancel: %d\n",
425 __func__, cmd_failed,
426 cmd_cancel));
427 cmd_cancel = 0;
428 cmd_failed = 0;
429 ++devices_failed;
430 }
431 }
432
433 SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
434 "Total of %d commands on %d"
435 " devices require eh work\n",
436 total_failures, devices_failed));
437}
438#endif
439
440 /**
441 * scsi_report_lun_change - Set flag on all *other* devices on the same target
442 * to indicate that a UNIT ATTENTION is expected.
443 * @sdev: Device reporting the UNIT ATTENTION
444 */
445static void scsi_report_lun_change(struct scsi_device *sdev)
446{
447 sdev->sdev_target->expecting_lun_change = 1;
448}
449
450/**
451 * scsi_report_sense - Examine scsi sense information and log messages for
452 * certain conditions, also issue uevents for some of them.
453 * @sdev: Device reporting the sense code
454 * @sshdr: sshdr to be examined
455 */
456static void scsi_report_sense(struct scsi_device *sdev,
457 struct scsi_sense_hdr *sshdr)
458{
459 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
460
461 if (sshdr->sense_key == UNIT_ATTENTION) {
462 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
463 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
464 sdev_printk(KERN_WARNING, sdev,
465 "Inquiry data has changed");
466 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
467 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
468 scsi_report_lun_change(sdev);
469 sdev_printk(KERN_WARNING, sdev,
470 "LUN assignments on this target have "
471 "changed. The Linux SCSI layer does not "
472 "automatically remap LUN assignments.\n");
473 } else if (sshdr->asc == 0x3f)
474 sdev_printk(KERN_WARNING, sdev,
475 "Operating parameters on this target have "
476 "changed. The Linux SCSI layer does not "
477 "automatically adjust these parameters.\n");
478
479 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
480 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
481 sdev_printk(KERN_WARNING, sdev,
482 "Warning! Received an indication that the "
483 "LUN reached a thin provisioning soft "
484 "threshold.\n");
485 }
486
487 if (sshdr->asc == 0x29) {
488 evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
489 /*
490 * Do not print message if it is an expected side-effect
491 * of runtime PM.
492 */
493 if (!sdev->silence_suspend)
494 sdev_printk(KERN_WARNING, sdev,
495 "Power-on or device reset occurred\n");
496 }
497
498 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
499 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
500 sdev_printk(KERN_WARNING, sdev,
501 "Mode parameters changed");
502 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
503 evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
504 sdev_printk(KERN_WARNING, sdev,
505 "Asymmetric access state changed");
506 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
507 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
508 sdev_printk(KERN_WARNING, sdev,
509 "Capacity data has changed");
510 } else if (sshdr->asc == 0x2a)
511 sdev_printk(KERN_WARNING, sdev,
512 "Parameters changed");
513 }
514
515 if (evt_type != SDEV_EVT_MAXBITS) {
516 set_bit(evt_type, sdev->pending_events);
517 schedule_work(&sdev->event_work);
518 }
519}
520
521static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status)
522{
523 cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
524}
525
526/**
527 * scsi_check_sense - Examine scsi cmd sense
528 * @scmd: Cmd to have sense checked.
529 *
530 * Return value:
531 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
532 *
533 * Notes:
534 * When a deferred error is detected the current command has
535 * not been executed and needs retrying.
536 */
537enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
538{
539 struct scsi_device *sdev = scmd->device;
540 struct scsi_sense_hdr sshdr;
541
542 if (! scsi_command_normalize_sense(scmd, &sshdr))
543 return FAILED; /* no valid sense data */
544
545 scsi_report_sense(sdev, &sshdr);
546
547 if (scsi_sense_is_deferred(&sshdr))
548 return NEEDS_RETRY;
549
550 if (sdev->handler && sdev->handler->check_sense) {
551 enum scsi_disposition rc;
552
553 rc = sdev->handler->check_sense(sdev, &sshdr);
554 if (rc != SCSI_RETURN_NOT_HANDLED)
555 return rc;
556 /* handler does not care. Drop down to default handling */
557 }
558
559 if (scmd->cmnd[0] == TEST_UNIT_READY &&
560 scmd->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER)
561 /*
562 * nasty: for mid-layer issued TURs, we need to return the
563 * actual sense data without any recovery attempt. For eh
564 * issued ones, we need to try to recover and interpret
565 */
566 return SUCCESS;
567
568 /*
569 * Previous logic looked for FILEMARK, EOM or ILI which are
570 * mainly associated with tapes and returned SUCCESS.
571 */
572 if (sshdr.response_code == 0x70) {
573 /* fixed format */
574 if (scmd->sense_buffer[2] & 0xe0)
575 return SUCCESS;
576 } else {
577 /*
578 * descriptor format: look for "stream commands sense data
579 * descriptor" (see SSC-3). Assume single sense data
580 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
581 */
582 if ((sshdr.additional_length > 3) &&
583 (scmd->sense_buffer[8] == 0x4) &&
584 (scmd->sense_buffer[11] & 0xe0))
585 return SUCCESS;
586 }
587
588 switch (sshdr.sense_key) {
589 case NO_SENSE:
590 return SUCCESS;
591 case RECOVERED_ERROR:
592 return /* soft_error */ SUCCESS;
593
594 case ABORTED_COMMAND:
595 if (sshdr.asc == 0x10) /* DIF */
596 return SUCCESS;
597
598 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
599 return ADD_TO_MLQUEUE;
600 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
601 sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
602 return ADD_TO_MLQUEUE;
603
604 return NEEDS_RETRY;
605 case NOT_READY:
606 case UNIT_ATTENTION:
607 /*
608 * if we are expecting a cc/ua because of a bus reset that we
609 * performed, treat this just as a retry. otherwise this is
610 * information that we should pass up to the upper-level driver
611 * so that we can deal with it there.
612 */
613 if (scmd->device->expecting_cc_ua) {
614 /*
615 * Because some device does not queue unit
616 * attentions correctly, we carefully check
617 * additional sense code and qualifier so as
618 * not to squash media change unit attention.
619 */
620 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
621 scmd->device->expecting_cc_ua = 0;
622 return NEEDS_RETRY;
623 }
624 }
625 /*
626 * we might also expect a cc/ua if another LUN on the target
627 * reported a UA with an ASC/ASCQ of 3F 0E -
628 * REPORTED LUNS DATA HAS CHANGED.
629 */
630 if (scmd->device->sdev_target->expecting_lun_change &&
631 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
632 return NEEDS_RETRY;
633 /*
634 * if the device is in the process of becoming ready, we
635 * should retry.
636 */
637 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
638 return NEEDS_RETRY;
639 /*
640 * if the device is not started, we need to wake
641 * the error handler to start the motor
642 */
643 if (scmd->device->allow_restart &&
644 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
645 return FAILED;
646 /*
647 * Pass the UA upwards for a determination in the completion
648 * functions.
649 */
650 return SUCCESS;
651
652 /* these are not supported */
653 case DATA_PROTECT:
654 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
655 /* Thin provisioning hard threshold reached */
656 set_scsi_ml_byte(scmd, SCSIML_STAT_NOSPC);
657 return SUCCESS;
658 }
659 fallthrough;
660 case COPY_ABORTED:
661 case VOLUME_OVERFLOW:
662 case MISCOMPARE:
663 case BLANK_CHECK:
664 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
665 return SUCCESS;
666
667 case MEDIUM_ERROR:
668 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
669 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
670 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
671 set_scsi_ml_byte(scmd, SCSIML_STAT_MED_ERROR);
672 return SUCCESS;
673 }
674 return NEEDS_RETRY;
675
676 case HARDWARE_ERROR:
677 if (scmd->device->retry_hwerror)
678 return ADD_TO_MLQUEUE;
679 else
680 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
681 fallthrough;
682
683 case ILLEGAL_REQUEST:
684 if (sshdr.asc == 0x20 || /* Invalid command operation code */
685 sshdr.asc == 0x21 || /* Logical block address out of range */
686 sshdr.asc == 0x22 || /* Invalid function */
687 sshdr.asc == 0x24 || /* Invalid field in cdb */
688 sshdr.asc == 0x26 || /* Parameter value invalid */
689 sshdr.asc == 0x27) { /* Write protected */
690 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
691 }
692 return SUCCESS;
693
694 default:
695 return SUCCESS;
696 }
697}
698EXPORT_SYMBOL_GPL(scsi_check_sense);
699
700static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
701{
702 struct scsi_host_template *sht = sdev->host->hostt;
703 struct scsi_device *tmp_sdev;
704
705 if (!sht->track_queue_depth ||
706 sdev->queue_depth >= sdev->max_queue_depth)
707 return;
708
709 if (time_before(jiffies,
710 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
711 return;
712
713 if (time_before(jiffies,
714 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
715 return;
716
717 /*
718 * Walk all devices of a target and do
719 * ramp up on them.
720 */
721 shost_for_each_device(tmp_sdev, sdev->host) {
722 if (tmp_sdev->channel != sdev->channel ||
723 tmp_sdev->id != sdev->id ||
724 tmp_sdev->queue_depth == sdev->max_queue_depth)
725 continue;
726
727 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
728 sdev->last_queue_ramp_up = jiffies;
729 }
730}
731
732static void scsi_handle_queue_full(struct scsi_device *sdev)
733{
734 struct scsi_host_template *sht = sdev->host->hostt;
735 struct scsi_device *tmp_sdev;
736
737 if (!sht->track_queue_depth)
738 return;
739
740 shost_for_each_device(tmp_sdev, sdev->host) {
741 if (tmp_sdev->channel != sdev->channel ||
742 tmp_sdev->id != sdev->id)
743 continue;
744 /*
745 * We do not know the number of commands that were at
746 * the device when we got the queue full so we start
747 * from the highest possible value and work our way down.
748 */
749 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
750 }
751}
752
753/**
754 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
755 * @scmd: SCSI cmd to examine.
756 *
757 * Notes:
758 * This is *only* called when we are examining the status of commands
759 * queued during error recovery. the main difference here is that we
760 * don't allow for the possibility of retries here, and we are a lot
761 * more restrictive about what we consider acceptable.
762 */
763static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
764{
765 /*
766 * first check the host byte, to see if there is anything in there
767 * that would indicate what we need to do.
768 */
769 if (host_byte(scmd->result) == DID_RESET) {
770 /*
771 * rats. we are already in the error handler, so we now
772 * get to try and figure out what to do next. if the sense
773 * is valid, we have a pretty good idea of what to do.
774 * if not, we mark it as FAILED.
775 */
776 return scsi_check_sense(scmd);
777 }
778 if (host_byte(scmd->result) != DID_OK)
779 return FAILED;
780
781 /*
782 * now, check the status byte to see if this indicates
783 * anything special.
784 */
785 switch (get_status_byte(scmd)) {
786 case SAM_STAT_GOOD:
787 scsi_handle_queue_ramp_up(scmd->device);
788 fallthrough;
789 case SAM_STAT_COMMAND_TERMINATED:
790 return SUCCESS;
791 case SAM_STAT_CHECK_CONDITION:
792 return scsi_check_sense(scmd);
793 case SAM_STAT_CONDITION_MET:
794 case SAM_STAT_INTERMEDIATE:
795 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
796 /*
797 * who knows? FIXME(eric)
798 */
799 return SUCCESS;
800 case SAM_STAT_RESERVATION_CONFLICT:
801 if (scmd->cmnd[0] == TEST_UNIT_READY)
802 /* it is a success, we probed the device and
803 * found it */
804 return SUCCESS;
805 /* otherwise, we failed to send the command */
806 return FAILED;
807 case SAM_STAT_TASK_SET_FULL:
808 scsi_handle_queue_full(scmd->device);
809 fallthrough;
810 case SAM_STAT_BUSY:
811 return NEEDS_RETRY;
812 default:
813 return FAILED;
814 }
815 return FAILED;
816}
817
818/**
819 * scsi_eh_done - Completion function for error handling.
820 * @scmd: Cmd that is done.
821 */
822void scsi_eh_done(struct scsi_cmnd *scmd)
823{
824 struct completion *eh_action;
825
826 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
827 "%s result: %x\n", __func__, scmd->result));
828
829 eh_action = scmd->device->host->eh_action;
830 if (eh_action)
831 complete(eh_action);
832}
833
834/**
835 * scsi_try_host_reset - ask host adapter to reset itself
836 * @scmd: SCSI cmd to send host reset.
837 */
838static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
839{
840 unsigned long flags;
841 enum scsi_disposition rtn;
842 struct Scsi_Host *host = scmd->device->host;
843 struct scsi_host_template *hostt = host->hostt;
844
845 SCSI_LOG_ERROR_RECOVERY(3,
846 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
847
848 if (!hostt->eh_host_reset_handler)
849 return FAILED;
850
851 rtn = hostt->eh_host_reset_handler(scmd);
852
853 if (rtn == SUCCESS) {
854 if (!hostt->skip_settle_delay)
855 ssleep(HOST_RESET_SETTLE_TIME);
856 spin_lock_irqsave(host->host_lock, flags);
857 scsi_report_bus_reset(host, scmd_channel(scmd));
858 spin_unlock_irqrestore(host->host_lock, flags);
859 }
860
861 return rtn;
862}
863
864/**
865 * scsi_try_bus_reset - ask host to perform a bus reset
866 * @scmd: SCSI cmd to send bus reset.
867 */
868static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
869{
870 unsigned long flags;
871 enum scsi_disposition rtn;
872 struct Scsi_Host *host = scmd->device->host;
873 struct scsi_host_template *hostt = host->hostt;
874
875 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
876 "%s: Snd Bus RST\n", __func__));
877
878 if (!hostt->eh_bus_reset_handler)
879 return FAILED;
880
881 rtn = hostt->eh_bus_reset_handler(scmd);
882
883 if (rtn == SUCCESS) {
884 if (!hostt->skip_settle_delay)
885 ssleep(BUS_RESET_SETTLE_TIME);
886 spin_lock_irqsave(host->host_lock, flags);
887 scsi_report_bus_reset(host, scmd_channel(scmd));
888 spin_unlock_irqrestore(host->host_lock, flags);
889 }
890
891 return rtn;
892}
893
894static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
895{
896 sdev->was_reset = 1;
897 sdev->expecting_cc_ua = 1;
898}
899
900/**
901 * scsi_try_target_reset - Ask host to perform a target reset
902 * @scmd: SCSI cmd used to send a target reset
903 *
904 * Notes:
905 * There is no timeout for this operation. if this operation is
906 * unreliable for a given host, then the host itself needs to put a
907 * timer on it, and set the host back to a consistent state prior to
908 * returning.
909 */
910static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
911{
912 unsigned long flags;
913 enum scsi_disposition rtn;
914 struct Scsi_Host *host = scmd->device->host;
915 struct scsi_host_template *hostt = host->hostt;
916
917 if (!hostt->eh_target_reset_handler)
918 return FAILED;
919
920 rtn = hostt->eh_target_reset_handler(scmd);
921 if (rtn == SUCCESS) {
922 spin_lock_irqsave(host->host_lock, flags);
923 __starget_for_each_device(scsi_target(scmd->device), NULL,
924 __scsi_report_device_reset);
925 spin_unlock_irqrestore(host->host_lock, flags);
926 }
927
928 return rtn;
929}
930
931/**
932 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
933 * @scmd: SCSI cmd used to send BDR
934 *
935 * Notes:
936 * There is no timeout for this operation. if this operation is
937 * unreliable for a given host, then the host itself needs to put a
938 * timer on it, and set the host back to a consistent state prior to
939 * returning.
940 */
941static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
942{
943 enum scsi_disposition rtn;
944 struct scsi_host_template *hostt = scmd->device->host->hostt;
945
946 if (!hostt->eh_device_reset_handler)
947 return FAILED;
948
949 rtn = hostt->eh_device_reset_handler(scmd);
950 if (rtn == SUCCESS)
951 __scsi_report_device_reset(scmd->device, NULL);
952 return rtn;
953}
954
955/**
956 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
957 * @hostt: SCSI driver host template
958 * @scmd: SCSI cmd used to send a target reset
959 *
960 * Return value:
961 * SUCCESS, FAILED, or FAST_IO_FAIL
962 *
963 * Notes:
964 * SUCCESS does not necessarily indicate that the command
965 * has been aborted; it only indicates that the LLDDs
966 * has cleared all references to that command.
967 * LLDDs should return FAILED only if an abort was required
968 * but could not be executed. LLDDs should return FAST_IO_FAIL
969 * if the device is temporarily unavailable (eg due to a
970 * link down on FibreChannel)
971 */
972static enum scsi_disposition
973scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
974{
975 if (!hostt->eh_abort_handler)
976 return FAILED;
977
978 return hostt->eh_abort_handler(scmd);
979}
980
981static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
982{
983 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
984 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
985 if (scsi_try_target_reset(scmd) != SUCCESS)
986 if (scsi_try_bus_reset(scmd) != SUCCESS)
987 scsi_try_host_reset(scmd);
988}
989
990/**
991 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
992 * @scmd: SCSI command structure to hijack
993 * @ses: structure to save restore information
994 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
995 * @cmnd_size: size in bytes of @cmnd (must be <= MAX_COMMAND_SIZE)
996 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
997 *
998 * This function is used to save a scsi command information before re-execution
999 * as part of the error recovery process. If @sense_bytes is 0 the command
1000 * sent must be one that does not transfer any data. If @sense_bytes != 0
1001 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
1002 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
1003 */
1004void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
1005 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
1006{
1007 struct scsi_device *sdev = scmd->device;
1008
1009 /*
1010 * We need saved copies of a number of fields - this is because
1011 * error handling may need to overwrite these with different values
1012 * to run different commands, and once error handling is complete,
1013 * we will need to restore these values prior to running the actual
1014 * command.
1015 */
1016 ses->cmd_len = scmd->cmd_len;
1017 ses->data_direction = scmd->sc_data_direction;
1018 ses->sdb = scmd->sdb;
1019 ses->result = scmd->result;
1020 ses->resid_len = scmd->resid_len;
1021 ses->underflow = scmd->underflow;
1022 ses->prot_op = scmd->prot_op;
1023 ses->eh_eflags = scmd->eh_eflags;
1024
1025 scmd->prot_op = SCSI_PROT_NORMAL;
1026 scmd->eh_eflags = 0;
1027 memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd));
1028 memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
1029 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1030 scmd->result = 0;
1031 scmd->resid_len = 0;
1032
1033 if (sense_bytes) {
1034 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
1035 sense_bytes);
1036 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1037 scmd->sdb.length);
1038 scmd->sdb.table.sgl = &ses->sense_sgl;
1039 scmd->sc_data_direction = DMA_FROM_DEVICE;
1040 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1041 scmd->cmnd[0] = REQUEST_SENSE;
1042 scmd->cmnd[4] = scmd->sdb.length;
1043 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1044 } else {
1045 scmd->sc_data_direction = DMA_NONE;
1046 if (cmnd) {
1047 BUG_ON(cmnd_size > sizeof(scmd->cmnd));
1048 memcpy(scmd->cmnd, cmnd, cmnd_size);
1049 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1050 }
1051 }
1052
1053 scmd->underflow = 0;
1054
1055 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1056 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1057 (sdev->lun << 5 & 0xe0);
1058
1059 /*
1060 * Zero the sense buffer. The scsi spec mandates that any
1061 * untransferred sense data should be interpreted as being zero.
1062 */
1063 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1064}
1065EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1066
1067/**
1068 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
1069 * @scmd: SCSI command structure to restore
1070 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
1071 *
1072 * Undo any damage done by above scsi_eh_prep_cmnd().
1073 */
1074void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1075{
1076 /*
1077 * Restore original data
1078 */
1079 scmd->cmd_len = ses->cmd_len;
1080 memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd));
1081 scmd->sc_data_direction = ses->data_direction;
1082 scmd->sdb = ses->sdb;
1083 scmd->result = ses->result;
1084 scmd->resid_len = ses->resid_len;
1085 scmd->underflow = ses->underflow;
1086 scmd->prot_op = ses->prot_op;
1087 scmd->eh_eflags = ses->eh_eflags;
1088}
1089EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1090
1091/**
1092 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1093 * @scmd: SCSI command structure to hijack
1094 * @cmnd: CDB to send
1095 * @cmnd_size: size in bytes of @cmnd
1096 * @timeout: timeout for this request
1097 * @sense_bytes: size of sense data to copy or 0
1098 *
1099 * This function is used to send a scsi command down to a target device
1100 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1101 *
1102 * Return value:
1103 * SUCCESS or FAILED or NEEDS_RETRY
1104 */
1105static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1106 unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1107{
1108 struct scsi_device *sdev = scmd->device;
1109 struct Scsi_Host *shost = sdev->host;
1110 DECLARE_COMPLETION_ONSTACK(done);
1111 unsigned long timeleft = timeout, delay;
1112 struct scsi_eh_save ses;
1113 const unsigned long stall_for = msecs_to_jiffies(100);
1114 int rtn;
1115
1116retry:
1117 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1118 shost->eh_action = &done;
1119
1120 scsi_log_send(scmd);
1121 scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
1122
1123 /*
1124 * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1125 * change the SCSI device state after we have examined it and before
1126 * .queuecommand() is called.
1127 */
1128 mutex_lock(&sdev->state_mutex);
1129 while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1130 mutex_unlock(&sdev->state_mutex);
1131 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1132 "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1133 SDEV_BLOCK));
1134 delay = min(timeleft, stall_for);
1135 timeleft -= delay;
1136 msleep(jiffies_to_msecs(delay));
1137 mutex_lock(&sdev->state_mutex);
1138 }
1139 if (sdev->sdev_state != SDEV_BLOCK)
1140 rtn = shost->hostt->queuecommand(shost, scmd);
1141 else
1142 rtn = FAILED;
1143 mutex_unlock(&sdev->state_mutex);
1144
1145 if (rtn) {
1146 if (timeleft > stall_for) {
1147 scsi_eh_restore_cmnd(scmd, &ses);
1148
1149 timeleft -= stall_for;
1150 msleep(jiffies_to_msecs(stall_for));
1151 goto retry;
1152 }
1153 /* signal not to enter either branch of the if () below */
1154 timeleft = 0;
1155 rtn = FAILED;
1156 } else {
1157 timeleft = wait_for_completion_timeout(&done, timeout);
1158 rtn = SUCCESS;
1159 }
1160
1161 shost->eh_action = NULL;
1162
1163 scsi_log_completion(scmd, rtn);
1164
1165 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1166 "%s timeleft: %ld\n",
1167 __func__, timeleft));
1168
1169 /*
1170 * If there is time left scsi_eh_done got called, and we will examine
1171 * the actual status codes to see whether the command actually did
1172 * complete normally, else if we have a zero return and no time left,
1173 * the command must still be pending, so abort it and return FAILED.
1174 * If we never actually managed to issue the command, because
1175 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1176 * value above (so don't execute either branch of the if)
1177 */
1178 if (timeleft) {
1179 rtn = scsi_eh_completed_normally(scmd);
1180 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1181 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1182
1183 switch (rtn) {
1184 case SUCCESS:
1185 case NEEDS_RETRY:
1186 case FAILED:
1187 break;
1188 case ADD_TO_MLQUEUE:
1189 rtn = NEEDS_RETRY;
1190 break;
1191 default:
1192 rtn = FAILED;
1193 break;
1194 }
1195 } else if (rtn != FAILED) {
1196 scsi_abort_eh_cmnd(scmd);
1197 rtn = FAILED;
1198 }
1199
1200 scsi_eh_restore_cmnd(scmd, &ses);
1201
1202 return rtn;
1203}
1204
1205/**
1206 * scsi_request_sense - Request sense data from a particular target.
1207 * @scmd: SCSI cmd for request sense.
1208 *
1209 * Notes:
1210 * Some hosts automatically obtain this information, others require
1211 * that we obtain it on our own. This function will *not* return until
1212 * the command either times out, or it completes.
1213 */
1214static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1215{
1216 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1217}
1218
1219static enum scsi_disposition
1220scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1221{
1222 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
1223 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1224 if (sdrv->eh_action)
1225 rtn = sdrv->eh_action(scmd, rtn);
1226 }
1227 return rtn;
1228}
1229
1230/**
1231 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1232 * @scmd: Original SCSI cmd that eh has finished.
1233 * @done_q: Queue for processed commands.
1234 *
1235 * Notes:
1236 * We don't want to use the normal command completion while we are are
1237 * still handling errors - it may cause other commands to be queued,
1238 * and that would disturb what we are doing. Thus we really want to
1239 * keep a list of pending commands for final completion, and once we
1240 * are ready to leave error handling we handle completion for real.
1241 */
1242void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1243{
1244 list_move_tail(&scmd->eh_entry, done_q);
1245}
1246EXPORT_SYMBOL(scsi_eh_finish_cmd);
1247
1248/**
1249 * scsi_eh_get_sense - Get device sense data.
1250 * @work_q: Queue of commands to process.
1251 * @done_q: Queue of processed commands.
1252 *
1253 * Description:
1254 * See if we need to request sense information. if so, then get it
1255 * now, so we have a better idea of what to do.
1256 *
1257 * Notes:
1258 * This has the unfortunate side effect that if a shost adapter does
1259 * not automatically request sense information, we end up shutting
1260 * it down before we request it.
1261 *
1262 * All drivers should request sense information internally these days,
1263 * so for now all I have to say is tough noogies if you end up in here.
1264 *
1265 * XXX: Long term this code should go away, but that needs an audit of
1266 * all LLDDs first.
1267 */
1268int scsi_eh_get_sense(struct list_head *work_q,
1269 struct list_head *done_q)
1270{
1271 struct scsi_cmnd *scmd, *next;
1272 struct Scsi_Host *shost;
1273 enum scsi_disposition rtn;
1274
1275 /*
1276 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1277 * should not get sense.
1278 */
1279 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1280 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1281 SCSI_SENSE_VALID(scmd))
1282 continue;
1283
1284 shost = scmd->device->host;
1285 if (scsi_host_eh_past_deadline(shost)) {
1286 SCSI_LOG_ERROR_RECOVERY(3,
1287 scmd_printk(KERN_INFO, scmd,
1288 "%s: skip request sense, past eh deadline\n",
1289 current->comm));
1290 break;
1291 }
1292 if (!scsi_status_is_check_condition(scmd->result))
1293 /*
1294 * don't request sense if there's no check condition
1295 * status because the error we're processing isn't one
1296 * that has a sense code (and some devices get
1297 * confused by sense requests out of the blue)
1298 */
1299 continue;
1300
1301 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1302 "%s: requesting sense\n",
1303 current->comm));
1304 rtn = scsi_request_sense(scmd);
1305 if (rtn != SUCCESS)
1306 continue;
1307
1308 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1309 "sense requested, result %x\n", scmd->result));
1310 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1311
1312 rtn = scsi_decide_disposition(scmd);
1313
1314 /*
1315 * if the result was normal, then just pass it along to the
1316 * upper level.
1317 */
1318 if (rtn == SUCCESS)
1319 /*
1320 * We don't want this command reissued, just finished
1321 * with the sense data, so set retries to the max
1322 * allowed to ensure it won't get reissued. If the user
1323 * has requested infinite retries, we also want to
1324 * finish this command, so force completion by setting
1325 * retries and allowed to the same value.
1326 */
1327 if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1328 scmd->retries = scmd->allowed = 1;
1329 else
1330 scmd->retries = scmd->allowed;
1331 else if (rtn != NEEDS_RETRY)
1332 continue;
1333
1334 scsi_eh_finish_cmd(scmd, done_q);
1335 }
1336
1337 return list_empty(work_q);
1338}
1339EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1340
1341/**
1342 * scsi_eh_tur - Send TUR to device.
1343 * @scmd: &scsi_cmnd to send TUR
1344 *
1345 * Return value:
1346 * 0 - Device is ready. 1 - Device NOT ready.
1347 */
1348static int scsi_eh_tur(struct scsi_cmnd *scmd)
1349{
1350 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1351 int retry_cnt = 1;
1352 enum scsi_disposition rtn;
1353
1354retry_tur:
1355 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1356 scmd->device->eh_timeout, 0);
1357
1358 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1359 "%s return: %x\n", __func__, rtn));
1360
1361 switch (rtn) {
1362 case NEEDS_RETRY:
1363 if (retry_cnt--)
1364 goto retry_tur;
1365 fallthrough;
1366 case SUCCESS:
1367 return 0;
1368 default:
1369 return 1;
1370 }
1371}
1372
1373/**
1374 * scsi_eh_test_devices - check if devices are responding from error recovery.
1375 * @cmd_list: scsi commands in error recovery.
1376 * @work_q: queue for commands which still need more error recovery
1377 * @done_q: queue for commands which are finished
1378 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1379 *
1380 * Decription:
1381 * Tests if devices are in a working state. Commands to devices now in
1382 * a working state are sent to the done_q while commands to devices which
1383 * are still failing to respond are returned to the work_q for more
1384 * processing.
1385 **/
1386static int scsi_eh_test_devices(struct list_head *cmd_list,
1387 struct list_head *work_q,
1388 struct list_head *done_q, int try_stu)
1389{
1390 struct scsi_cmnd *scmd, *next;
1391 struct scsi_device *sdev;
1392 int finish_cmds;
1393
1394 while (!list_empty(cmd_list)) {
1395 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1396 sdev = scmd->device;
1397
1398 if (!try_stu) {
1399 if (scsi_host_eh_past_deadline(sdev->host)) {
1400 /* Push items back onto work_q */
1401 list_splice_init(cmd_list, work_q);
1402 SCSI_LOG_ERROR_RECOVERY(3,
1403 sdev_printk(KERN_INFO, sdev,
1404 "%s: skip test device, past eh deadline",
1405 current->comm));
1406 break;
1407 }
1408 }
1409
1410 finish_cmds = !scsi_device_online(scmd->device) ||
1411 (try_stu && !scsi_eh_try_stu(scmd) &&
1412 !scsi_eh_tur(scmd)) ||
1413 !scsi_eh_tur(scmd);
1414
1415 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1416 if (scmd->device == sdev) {
1417 if (finish_cmds &&
1418 (try_stu ||
1419 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1420 scsi_eh_finish_cmd(scmd, done_q);
1421 else
1422 list_move_tail(&scmd->eh_entry, work_q);
1423 }
1424 }
1425 return list_empty(work_q);
1426}
1427
1428/**
1429 * scsi_eh_try_stu - Send START_UNIT to device.
1430 * @scmd: &scsi_cmnd to send START_UNIT
1431 *
1432 * Return value:
1433 * 0 - Device is ready. 1 - Device NOT ready.
1434 */
1435static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1436{
1437 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1438
1439 if (scmd->device->allow_restart) {
1440 int i;
1441 enum scsi_disposition rtn = NEEDS_RETRY;
1442
1443 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1444 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
1445 scmd->device->eh_timeout, 0);
1446
1447 if (rtn == SUCCESS)
1448 return 0;
1449 }
1450
1451 return 1;
1452}
1453
1454 /**
1455 * scsi_eh_stu - send START_UNIT if needed
1456 * @shost: &scsi host being recovered.
1457 * @work_q: &list_head for pending commands.
1458 * @done_q: &list_head for processed commands.
1459 *
1460 * Notes:
1461 * If commands are failing due to not ready, initializing command required,
1462 * try revalidating the device, which will end up sending a start unit.
1463 */
1464static int scsi_eh_stu(struct Scsi_Host *shost,
1465 struct list_head *work_q,
1466 struct list_head *done_q)
1467{
1468 struct scsi_cmnd *scmd, *stu_scmd, *next;
1469 struct scsi_device *sdev;
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 START_UNIT, past eh deadline\n",
1476 current->comm));
1477 scsi_device_put(sdev);
1478 break;
1479 }
1480 stu_scmd = NULL;
1481 list_for_each_entry(scmd, work_q, eh_entry)
1482 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1483 scsi_check_sense(scmd) == FAILED ) {
1484 stu_scmd = scmd;
1485 break;
1486 }
1487
1488 if (!stu_scmd)
1489 continue;
1490
1491 SCSI_LOG_ERROR_RECOVERY(3,
1492 sdev_printk(KERN_INFO, sdev,
1493 "%s: Sending START_UNIT\n",
1494 current->comm));
1495
1496 if (!scsi_eh_try_stu(stu_scmd)) {
1497 if (!scsi_device_online(sdev) ||
1498 !scsi_eh_tur(stu_scmd)) {
1499 list_for_each_entry_safe(scmd, next,
1500 work_q, eh_entry) {
1501 if (scmd->device == sdev &&
1502 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1503 scsi_eh_finish_cmd(scmd, done_q);
1504 }
1505 }
1506 } else {
1507 SCSI_LOG_ERROR_RECOVERY(3,
1508 sdev_printk(KERN_INFO, sdev,
1509 "%s: START_UNIT failed\n",
1510 current->comm));
1511 }
1512 }
1513
1514 return list_empty(work_q);
1515}
1516
1517
1518/**
1519 * scsi_eh_bus_device_reset - send bdr if needed
1520 * @shost: scsi host being recovered.
1521 * @work_q: &list_head for pending commands.
1522 * @done_q: &list_head for processed commands.
1523 *
1524 * Notes:
1525 * Try a bus device reset. Still, look to see whether we have multiple
1526 * devices that are jammed or not - if we have multiple devices, it
1527 * makes no sense to try bus_device_reset - we really would need to try
1528 * a bus_reset instead.
1529 */
1530static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1531 struct list_head *work_q,
1532 struct list_head *done_q)
1533{
1534 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1535 struct scsi_device *sdev;
1536 enum scsi_disposition rtn;
1537
1538 shost_for_each_device(sdev, shost) {
1539 if (scsi_host_eh_past_deadline(shost)) {
1540 SCSI_LOG_ERROR_RECOVERY(3,
1541 sdev_printk(KERN_INFO, sdev,
1542 "%s: skip BDR, past eh deadline\n",
1543 current->comm));
1544 scsi_device_put(sdev);
1545 break;
1546 }
1547 bdr_scmd = NULL;
1548 list_for_each_entry(scmd, work_q, eh_entry)
1549 if (scmd->device == sdev) {
1550 bdr_scmd = scmd;
1551 break;
1552 }
1553
1554 if (!bdr_scmd)
1555 continue;
1556
1557 SCSI_LOG_ERROR_RECOVERY(3,
1558 sdev_printk(KERN_INFO, sdev,
1559 "%s: Sending BDR\n", current->comm));
1560 rtn = scsi_try_bus_device_reset(bdr_scmd);
1561 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1562 if (!scsi_device_online(sdev) ||
1563 rtn == FAST_IO_FAIL ||
1564 !scsi_eh_tur(bdr_scmd)) {
1565 list_for_each_entry_safe(scmd, next,
1566 work_q, eh_entry) {
1567 if (scmd->device == sdev &&
1568 scsi_eh_action(scmd, rtn) != FAILED)
1569 scsi_eh_finish_cmd(scmd,
1570 done_q);
1571 }
1572 }
1573 } else {
1574 SCSI_LOG_ERROR_RECOVERY(3,
1575 sdev_printk(KERN_INFO, sdev,
1576 "%s: BDR failed\n", current->comm));
1577 }
1578 }
1579
1580 return list_empty(work_q);
1581}
1582
1583/**
1584 * scsi_eh_target_reset - send target reset if needed
1585 * @shost: scsi host being recovered.
1586 * @work_q: &list_head for pending commands.
1587 * @done_q: &list_head for processed commands.
1588 *
1589 * Notes:
1590 * Try a target reset.
1591 */
1592static int scsi_eh_target_reset(struct Scsi_Host *shost,
1593 struct list_head *work_q,
1594 struct list_head *done_q)
1595{
1596 LIST_HEAD(tmp_list);
1597 LIST_HEAD(check_list);
1598
1599 list_splice_init(work_q, &tmp_list);
1600
1601 while (!list_empty(&tmp_list)) {
1602 struct scsi_cmnd *next, *scmd;
1603 enum scsi_disposition rtn;
1604 unsigned int id;
1605
1606 if (scsi_host_eh_past_deadline(shost)) {
1607 /* push back on work queue for further processing */
1608 list_splice_init(&check_list, work_q);
1609 list_splice_init(&tmp_list, work_q);
1610 SCSI_LOG_ERROR_RECOVERY(3,
1611 shost_printk(KERN_INFO, shost,
1612 "%s: Skip target reset, past eh deadline\n",
1613 current->comm));
1614 return list_empty(work_q);
1615 }
1616
1617 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1618 id = scmd_id(scmd);
1619
1620 SCSI_LOG_ERROR_RECOVERY(3,
1621 shost_printk(KERN_INFO, shost,
1622 "%s: Sending target reset to target %d\n",
1623 current->comm, id));
1624 rtn = scsi_try_target_reset(scmd);
1625 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1626 SCSI_LOG_ERROR_RECOVERY(3,
1627 shost_printk(KERN_INFO, shost,
1628 "%s: Target reset failed"
1629 " target: %d\n",
1630 current->comm, id));
1631 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1632 if (scmd_id(scmd) != id)
1633 continue;
1634
1635 if (rtn == SUCCESS)
1636 list_move_tail(&scmd->eh_entry, &check_list);
1637 else if (rtn == FAST_IO_FAIL)
1638 scsi_eh_finish_cmd(scmd, done_q);
1639 else
1640 /* push back on work queue for further processing */
1641 list_move(&scmd->eh_entry, work_q);
1642 }
1643 }
1644
1645 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1646}
1647
1648/**
1649 * scsi_eh_bus_reset - send a bus reset
1650 * @shost: &scsi host being recovered.
1651 * @work_q: &list_head for pending commands.
1652 * @done_q: &list_head for processed commands.
1653 */
1654static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1655 struct list_head *work_q,
1656 struct list_head *done_q)
1657{
1658 struct scsi_cmnd *scmd, *chan_scmd, *next;
1659 LIST_HEAD(check_list);
1660 unsigned int channel;
1661 enum scsi_disposition rtn;
1662
1663 /*
1664 * we really want to loop over the various channels, and do this on
1665 * a channel by channel basis. we should also check to see if any
1666 * of the failed commands are on soft_reset devices, and if so, skip
1667 * the reset.
1668 */
1669
1670 for (channel = 0; channel <= shost->max_channel; channel++) {
1671 if (scsi_host_eh_past_deadline(shost)) {
1672 list_splice_init(&check_list, work_q);
1673 SCSI_LOG_ERROR_RECOVERY(3,
1674 shost_printk(KERN_INFO, shost,
1675 "%s: skip BRST, past eh deadline\n",
1676 current->comm));
1677 return list_empty(work_q);
1678 }
1679
1680 chan_scmd = NULL;
1681 list_for_each_entry(scmd, work_q, eh_entry) {
1682 if (channel == scmd_channel(scmd)) {
1683 chan_scmd = scmd;
1684 break;
1685 /*
1686 * FIXME add back in some support for
1687 * soft_reset devices.
1688 */
1689 }
1690 }
1691
1692 if (!chan_scmd)
1693 continue;
1694 SCSI_LOG_ERROR_RECOVERY(3,
1695 shost_printk(KERN_INFO, shost,
1696 "%s: Sending BRST chan: %d\n",
1697 current->comm, channel));
1698 rtn = scsi_try_bus_reset(chan_scmd);
1699 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1700 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1701 if (channel == scmd_channel(scmd)) {
1702 if (rtn == FAST_IO_FAIL)
1703 scsi_eh_finish_cmd(scmd,
1704 done_q);
1705 else
1706 list_move_tail(&scmd->eh_entry,
1707 &check_list);
1708 }
1709 }
1710 } else {
1711 SCSI_LOG_ERROR_RECOVERY(3,
1712 shost_printk(KERN_INFO, shost,
1713 "%s: BRST failed chan: %d\n",
1714 current->comm, channel));
1715 }
1716 }
1717 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1718}
1719
1720/**
1721 * scsi_eh_host_reset - send a host reset
1722 * @shost: host to be reset.
1723 * @work_q: &list_head for pending commands.
1724 * @done_q: &list_head for processed commands.
1725 */
1726static int scsi_eh_host_reset(struct Scsi_Host *shost,
1727 struct list_head *work_q,
1728 struct list_head *done_q)
1729{
1730 struct scsi_cmnd *scmd, *next;
1731 LIST_HEAD(check_list);
1732 enum scsi_disposition rtn;
1733
1734 if (!list_empty(work_q)) {
1735 scmd = list_entry(work_q->next,
1736 struct scsi_cmnd, eh_entry);
1737
1738 SCSI_LOG_ERROR_RECOVERY(3,
1739 shost_printk(KERN_INFO, shost,
1740 "%s: Sending HRST\n",
1741 current->comm));
1742
1743 rtn = scsi_try_host_reset(scmd);
1744 if (rtn == SUCCESS) {
1745 list_splice_init(work_q, &check_list);
1746 } else if (rtn == FAST_IO_FAIL) {
1747 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1748 scsi_eh_finish_cmd(scmd, done_q);
1749 }
1750 } else {
1751 SCSI_LOG_ERROR_RECOVERY(3,
1752 shost_printk(KERN_INFO, shost,
1753 "%s: HRST failed\n",
1754 current->comm));
1755 }
1756 }
1757 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1758}
1759
1760/**
1761 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1762 * @work_q: &list_head for pending commands.
1763 * @done_q: &list_head for processed commands.
1764 */
1765static void scsi_eh_offline_sdevs(struct list_head *work_q,
1766 struct list_head *done_q)
1767{
1768 struct scsi_cmnd *scmd, *next;
1769 struct scsi_device *sdev;
1770
1771 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1772 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1773 "not ready after error recovery\n");
1774 sdev = scmd->device;
1775
1776 mutex_lock(&sdev->state_mutex);
1777 scsi_device_set_state(sdev, SDEV_OFFLINE);
1778 mutex_unlock(&sdev->state_mutex);
1779
1780 scsi_eh_finish_cmd(scmd, done_q);
1781 }
1782 return;
1783}
1784
1785/**
1786 * scsi_noretry_cmd - determine if command should be failed fast
1787 * @scmd: SCSI cmd to examine.
1788 */
1789bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
1790{
1791 struct request *req = scsi_cmd_to_rq(scmd);
1792
1793 switch (host_byte(scmd->result)) {
1794 case DID_OK:
1795 break;
1796 case DID_TIME_OUT:
1797 goto check_type;
1798 case DID_BUS_BUSY:
1799 return !!(req->cmd_flags & REQ_FAILFAST_TRANSPORT);
1800 case DID_PARITY:
1801 return !!(req->cmd_flags & REQ_FAILFAST_DEV);
1802 case DID_ERROR:
1803 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1804 return false;
1805 fallthrough;
1806 case DID_SOFT_ERROR:
1807 return !!(req->cmd_flags & REQ_FAILFAST_DRIVER);
1808 }
1809
1810 if (!scsi_status_is_check_condition(scmd->result))
1811 return false;
1812
1813check_type:
1814 /*
1815 * assume caller has checked sense and determined
1816 * the check condition was retryable.
1817 */
1818 if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(req))
1819 return true;
1820
1821 return false;
1822}
1823
1824/**
1825 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1826 * @scmd: SCSI cmd to examine.
1827 *
1828 * Notes:
1829 * This is *only* called when we are examining the status after sending
1830 * out the actual data command. any commands that are queued for error
1831 * recovery (e.g. test_unit_ready) do *not* come through here.
1832 *
1833 * When this routine returns failed, it means the error handler thread
1834 * is woken. In cases where the error code indicates an error that
1835 * doesn't require the error handler read (i.e. we don't need to
1836 * abort/reset), this function should return SUCCESS.
1837 */
1838enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1839{
1840 enum scsi_disposition rtn;
1841
1842 /*
1843 * if the device is offline, then we clearly just pass the result back
1844 * up to the top level.
1845 */
1846 if (!scsi_device_online(scmd->device)) {
1847 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1848 "%s: device offline - report as SUCCESS\n", __func__));
1849 return SUCCESS;
1850 }
1851
1852 /*
1853 * first check the host byte, to see if there is anything in there
1854 * that would indicate what we need to do.
1855 */
1856 switch (host_byte(scmd->result)) {
1857 case DID_PASSTHROUGH:
1858 /*
1859 * no matter what, pass this through to the upper layer.
1860 * nuke this special code so that it looks like we are saying
1861 * did_ok.
1862 */
1863 scmd->result &= 0xff00ffff;
1864 return SUCCESS;
1865 case DID_OK:
1866 /*
1867 * looks good. drop through, and check the next byte.
1868 */
1869 break;
1870 case DID_ABORT:
1871 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1872 set_host_byte(scmd, DID_TIME_OUT);
1873 return SUCCESS;
1874 }
1875 fallthrough;
1876 case DID_NO_CONNECT:
1877 case DID_BAD_TARGET:
1878 /*
1879 * note - this means that we just report the status back
1880 * to the top level driver, not that we actually think
1881 * that it indicates SUCCESS.
1882 */
1883 return SUCCESS;
1884 case DID_SOFT_ERROR:
1885 /*
1886 * when the low level driver returns did_soft_error,
1887 * it is responsible for keeping an internal retry counter
1888 * in order to avoid endless loops (db)
1889 */
1890 goto maybe_retry;
1891 case DID_IMM_RETRY:
1892 return NEEDS_RETRY;
1893
1894 case DID_REQUEUE:
1895 return ADD_TO_MLQUEUE;
1896 case DID_TRANSPORT_DISRUPTED:
1897 /*
1898 * LLD/transport was disrupted during processing of the IO.
1899 * The transport class is now blocked/blocking,
1900 * and the transport will decide what to do with the IO
1901 * based on its timers and recovery capablilities if
1902 * there are enough retries.
1903 */
1904 goto maybe_retry;
1905 case DID_TRANSPORT_FAILFAST:
1906 /*
1907 * The transport decided to failfast the IO (most likely
1908 * the fast io fail tmo fired), so send IO directly upwards.
1909 */
1910 return SUCCESS;
1911 case DID_TRANSPORT_MARGINAL:
1912 /*
1913 * caller has decided not to do retries on
1914 * abort success, so send IO directly upwards
1915 */
1916 return SUCCESS;
1917 case DID_ERROR:
1918 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1919 /*
1920 * execute reservation conflict processing code
1921 * lower down
1922 */
1923 break;
1924 fallthrough;
1925 case DID_BUS_BUSY:
1926 case DID_PARITY:
1927 goto maybe_retry;
1928 case DID_TIME_OUT:
1929 /*
1930 * when we scan the bus, we get timeout messages for
1931 * these commands if there is no device available.
1932 * other hosts report did_no_connect for the same thing.
1933 */
1934 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1935 scmd->cmnd[0] == INQUIRY)) {
1936 return SUCCESS;
1937 } else {
1938 return FAILED;
1939 }
1940 case DID_RESET:
1941 return SUCCESS;
1942 default:
1943 return FAILED;
1944 }
1945
1946 /*
1947 * check the status byte to see if this indicates anything special.
1948 */
1949 switch (get_status_byte(scmd)) {
1950 case SAM_STAT_TASK_SET_FULL:
1951 scsi_handle_queue_full(scmd->device);
1952 /*
1953 * the case of trying to send too many commands to a
1954 * tagged queueing device.
1955 */
1956 fallthrough;
1957 case SAM_STAT_BUSY:
1958 /*
1959 * device can't talk to us at the moment. Should only
1960 * occur (SAM-3) when the task queue is empty, so will cause
1961 * the empty queue handling to trigger a stall in the
1962 * device.
1963 */
1964 return ADD_TO_MLQUEUE;
1965 case SAM_STAT_GOOD:
1966 if (scmd->cmnd[0] == REPORT_LUNS)
1967 scmd->device->sdev_target->expecting_lun_change = 0;
1968 scsi_handle_queue_ramp_up(scmd->device);
1969 fallthrough;
1970 case SAM_STAT_COMMAND_TERMINATED:
1971 return SUCCESS;
1972 case SAM_STAT_TASK_ABORTED:
1973 goto maybe_retry;
1974 case SAM_STAT_CHECK_CONDITION:
1975 rtn = scsi_check_sense(scmd);
1976 if (rtn == NEEDS_RETRY)
1977 goto maybe_retry;
1978 /* if rtn == FAILED, we have no sense information;
1979 * returning FAILED will wake the error handler thread
1980 * to collect the sense and redo the decide
1981 * disposition */
1982 return rtn;
1983 case SAM_STAT_CONDITION_MET:
1984 case SAM_STAT_INTERMEDIATE:
1985 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
1986 case SAM_STAT_ACA_ACTIVE:
1987 /*
1988 * who knows? FIXME(eric)
1989 */
1990 return SUCCESS;
1991
1992 case SAM_STAT_RESERVATION_CONFLICT:
1993 sdev_printk(KERN_INFO, scmd->device,
1994 "reservation conflict\n");
1995 set_scsi_ml_byte(scmd, SCSIML_STAT_RESV_CONFLICT);
1996 return SUCCESS; /* causes immediate i/o error */
1997 }
1998 return FAILED;
1999
2000maybe_retry:
2001
2002 /* we requeue for retry because the error was retryable, and
2003 * the request was not marked fast fail. Note that above,
2004 * even if the request is marked fast fail, we still requeue
2005 * for queue congestion conditions (QUEUE_FULL or BUSY) */
2006 if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
2007 return NEEDS_RETRY;
2008 } else {
2009 /*
2010 * no more retries - report this one back to upper level.
2011 */
2012 return SUCCESS;
2013 }
2014}
2015
2016static enum rq_end_io_ret eh_lock_door_done(struct request *req,
2017 blk_status_t status)
2018{
2019 blk_mq_free_request(req);
2020 return RQ_END_IO_NONE;
2021}
2022
2023/**
2024 * scsi_eh_lock_door - Prevent medium removal for the specified device
2025 * @sdev: SCSI device to prevent medium removal
2026 *
2027 * Locking:
2028 * We must be called from process context.
2029 *
2030 * Notes:
2031 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
2032 * head of the devices request queue, and continue.
2033 */
2034static void scsi_eh_lock_door(struct scsi_device *sdev)
2035{
2036 struct scsi_cmnd *scmd;
2037 struct request *req;
2038
2039 req = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
2040 if (IS_ERR(req))
2041 return;
2042 scmd = blk_mq_rq_to_pdu(req);
2043
2044 scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL;
2045 scmd->cmnd[1] = 0;
2046 scmd->cmnd[2] = 0;
2047 scmd->cmnd[3] = 0;
2048 scmd->cmnd[4] = SCSI_REMOVAL_PREVENT;
2049 scmd->cmnd[5] = 0;
2050 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
2051 scmd->allowed = 5;
2052
2053 req->rq_flags |= RQF_QUIET;
2054 req->timeout = 10 * HZ;
2055 req->end_io = eh_lock_door_done;
2056
2057 blk_execute_rq_nowait(req, true);
2058}
2059
2060/**
2061 * scsi_restart_operations - restart io operations to the specified host.
2062 * @shost: Host we are restarting.
2063 *
2064 * Notes:
2065 * When we entered the error handler, we blocked all further i/o to
2066 * this device. we need to 'reverse' this process.
2067 */
2068static void scsi_restart_operations(struct Scsi_Host *shost)
2069{
2070 struct scsi_device *sdev;
2071 unsigned long flags;
2072
2073 /*
2074 * If the door was locked, we need to insert a door lock request
2075 * onto the head of the SCSI request queue for the device. There
2076 * is no point trying to lock the door of an off-line device.
2077 */
2078 shost_for_each_device(sdev, shost) {
2079 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2080 scsi_eh_lock_door(sdev);
2081 sdev->was_reset = 0;
2082 }
2083 }
2084
2085 /*
2086 * next free up anything directly waiting upon the host. this
2087 * will be requests for character device operations, and also for
2088 * ioctls to queued block devices.
2089 */
2090 SCSI_LOG_ERROR_RECOVERY(3,
2091 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2092
2093 spin_lock_irqsave(shost->host_lock, flags);
2094 if (scsi_host_set_state(shost, SHOST_RUNNING))
2095 if (scsi_host_set_state(shost, SHOST_CANCEL))
2096 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2097 spin_unlock_irqrestore(shost->host_lock, flags);
2098
2099 wake_up(&shost->host_wait);
2100
2101 /*
2102 * finally we need to re-initiate requests that may be pending. we will
2103 * have had everything blocked while error handling is taking place, and
2104 * now that error recovery is done, we will need to ensure that these
2105 * requests are started.
2106 */
2107 scsi_run_host_queues(shost);
2108
2109 /*
2110 * if eh is active and host_eh_scheduled is pending we need to re-run
2111 * recovery. we do this check after scsi_run_host_queues() to allow
2112 * everything pent up since the last eh run a chance to make forward
2113 * progress before we sync again. Either we'll immediately re-run
2114 * recovery or scsi_device_unbusy() will wake us again when these
2115 * pending commands complete.
2116 */
2117 spin_lock_irqsave(shost->host_lock, flags);
2118 if (shost->host_eh_scheduled)
2119 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2120 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2121 spin_unlock_irqrestore(shost->host_lock, flags);
2122}
2123
2124/**
2125 * scsi_eh_ready_devs - check device ready state and recover if not.
2126 * @shost: host to be recovered.
2127 * @work_q: &list_head for pending commands.
2128 * @done_q: &list_head for processed commands.
2129 */
2130void scsi_eh_ready_devs(struct Scsi_Host *shost,
2131 struct list_head *work_q,
2132 struct list_head *done_q)
2133{
2134 if (!scsi_eh_stu(shost, work_q, done_q))
2135 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2136 if (!scsi_eh_target_reset(shost, work_q, done_q))
2137 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2138 if (!scsi_eh_host_reset(shost, work_q, done_q))
2139 scsi_eh_offline_sdevs(work_q,
2140 done_q);
2141}
2142EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2143
2144/**
2145 * scsi_eh_flush_done_q - finish processed commands or retry them.
2146 * @done_q: list_head of processed commands.
2147 */
2148void scsi_eh_flush_done_q(struct list_head *done_q)
2149{
2150 struct scsi_cmnd *scmd, *next;
2151
2152 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2153 list_del_init(&scmd->eh_entry);
2154 if (scsi_device_online(scmd->device) &&
2155 !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2156 scsi_eh_should_retry_cmd(scmd)) {
2157 SCSI_LOG_ERROR_RECOVERY(3,
2158 scmd_printk(KERN_INFO, scmd,
2159 "%s: flush retry cmd\n",
2160 current->comm));
2161 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2162 } else {
2163 /*
2164 * If just we got sense for the device (called
2165 * scsi_eh_get_sense), scmd->result is already
2166 * set, do not set DID_TIME_OUT.
2167 */
2168 if (!scmd->result)
2169 scmd->result |= (DID_TIME_OUT << 16);
2170 SCSI_LOG_ERROR_RECOVERY(3,
2171 scmd_printk(KERN_INFO, scmd,
2172 "%s: flush finish cmd\n",
2173 current->comm));
2174 scsi_finish_command(scmd);
2175 }
2176 }
2177}
2178EXPORT_SYMBOL(scsi_eh_flush_done_q);
2179
2180/**
2181 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2182 * @shost: Host to unjam.
2183 *
2184 * Notes:
2185 * When we come in here, we *know* that all commands on the bus have
2186 * either completed, failed or timed out. we also know that no further
2187 * commands are being sent to the host, so things are relatively quiet
2188 * and we have freedom to fiddle with things as we wish.
2189 *
2190 * This is only the *default* implementation. it is possible for
2191 * individual drivers to supply their own version of this function, and
2192 * if the maintainer wishes to do this, it is strongly suggested that
2193 * this function be taken as a template and modified. this function
2194 * was designed to correctly handle problems for about 95% of the
2195 * different cases out there, and it should always provide at least a
2196 * reasonable amount of error recovery.
2197 *
2198 * Any command marked 'failed' or 'timeout' must eventually have
2199 * scsi_finish_cmd() called for it. we do all of the retry stuff
2200 * here, so when we restart the host after we return it should have an
2201 * empty queue.
2202 */
2203static void scsi_unjam_host(struct Scsi_Host *shost)
2204{
2205 unsigned long flags;
2206 LIST_HEAD(eh_work_q);
2207 LIST_HEAD(eh_done_q);
2208
2209 spin_lock_irqsave(shost->host_lock, flags);
2210 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2211 spin_unlock_irqrestore(shost->host_lock, flags);
2212
2213 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2214
2215 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2216 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2217
2218 spin_lock_irqsave(shost->host_lock, flags);
2219 if (shost->eh_deadline != -1)
2220 shost->last_reset = 0;
2221 spin_unlock_irqrestore(shost->host_lock, flags);
2222 scsi_eh_flush_done_q(&eh_done_q);
2223}
2224
2225/**
2226 * scsi_error_handler - SCSI error handler thread
2227 * @data: Host for which we are running.
2228 *
2229 * Notes:
2230 * This is the main error handling loop. This is run as a kernel thread
2231 * for every SCSI host and handles all error handling activity.
2232 */
2233int scsi_error_handler(void *data)
2234{
2235 struct Scsi_Host *shost = data;
2236
2237 /*
2238 * We use TASK_INTERRUPTIBLE so that the thread is not
2239 * counted against the load average as a running process.
2240 * We never actually get interrupted because kthread_run
2241 * disables signal delivery for the created thread.
2242 */
2243 while (true) {
2244 /*
2245 * The sequence in kthread_stop() sets the stop flag first
2246 * then wakes the process. To avoid missed wakeups, the task
2247 * should always be in a non running state before the stop
2248 * flag is checked
2249 */
2250 set_current_state(TASK_INTERRUPTIBLE);
2251 if (kthread_should_stop())
2252 break;
2253
2254 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2255 shost->host_failed != scsi_host_busy(shost)) {
2256 SCSI_LOG_ERROR_RECOVERY(1,
2257 shost_printk(KERN_INFO, shost,
2258 "scsi_eh_%d: sleeping\n",
2259 shost->host_no));
2260 schedule();
2261 continue;
2262 }
2263
2264 __set_current_state(TASK_RUNNING);
2265 SCSI_LOG_ERROR_RECOVERY(1,
2266 shost_printk(KERN_INFO, shost,
2267 "scsi_eh_%d: waking up %d/%d/%d\n",
2268 shost->host_no, shost->host_eh_scheduled,
2269 shost->host_failed,
2270 scsi_host_busy(shost)));
2271
2272 /*
2273 * We have a host that is failing for some reason. Figure out
2274 * what we need to do to get it up and online again (if we can).
2275 * If we fail, we end up taking the thing offline.
2276 */
2277 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2278 SCSI_LOG_ERROR_RECOVERY(1,
2279 shost_printk(KERN_ERR, shost,
2280 "scsi_eh_%d: unable to autoresume\n",
2281 shost->host_no));
2282 continue;
2283 }
2284
2285 if (shost->transportt->eh_strategy_handler)
2286 shost->transportt->eh_strategy_handler(shost);
2287 else
2288 scsi_unjam_host(shost);
2289
2290 /* All scmds have been handled */
2291 shost->host_failed = 0;
2292
2293 /*
2294 * Note - if the above fails completely, the action is to take
2295 * individual devices offline and flush the queue of any
2296 * outstanding requests that may have been pending. When we
2297 * restart, we restart any I/O to any other devices on the bus
2298 * which are still online.
2299 */
2300 scsi_restart_operations(shost);
2301 if (!shost->eh_noresume)
2302 scsi_autopm_put_host(shost);
2303 }
2304 __set_current_state(TASK_RUNNING);
2305
2306 SCSI_LOG_ERROR_RECOVERY(1,
2307 shost_printk(KERN_INFO, shost,
2308 "Error handler scsi_eh_%d exiting\n",
2309 shost->host_no));
2310 shost->ehandler = NULL;
2311 return 0;
2312}
2313
2314/*
2315 * Function: scsi_report_bus_reset()
2316 *
2317 * Purpose: Utility function used by low-level drivers to report that
2318 * they have observed a bus reset on the bus being handled.
2319 *
2320 * Arguments: shost - Host in question
2321 * channel - channel on which reset was observed.
2322 *
2323 * Returns: Nothing
2324 *
2325 * Lock status: Host lock must be held.
2326 *
2327 * Notes: This only needs to be called if the reset is one which
2328 * originates from an unknown location. Resets originated
2329 * by the mid-level itself don't need to call this, but there
2330 * should be no harm.
2331 *
2332 * The main purpose of this is to make sure that a CHECK_CONDITION
2333 * is properly treated.
2334 */
2335void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2336{
2337 struct scsi_device *sdev;
2338
2339 __shost_for_each_device(sdev, shost) {
2340 if (channel == sdev_channel(sdev))
2341 __scsi_report_device_reset(sdev, NULL);
2342 }
2343}
2344EXPORT_SYMBOL(scsi_report_bus_reset);
2345
2346/*
2347 * Function: scsi_report_device_reset()
2348 *
2349 * Purpose: Utility function used by low-level drivers to report that
2350 * they have observed a device reset on the device being handled.
2351 *
2352 * Arguments: shost - Host in question
2353 * channel - channel on which reset was observed
2354 * target - target on which reset was observed
2355 *
2356 * Returns: Nothing
2357 *
2358 * Lock status: Host lock must be held
2359 *
2360 * Notes: This only needs to be called if the reset is one which
2361 * originates from an unknown location. Resets originated
2362 * by the mid-level itself don't need to call this, but there
2363 * should be no harm.
2364 *
2365 * The main purpose of this is to make sure that a CHECK_CONDITION
2366 * is properly treated.
2367 */
2368void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2369{
2370 struct scsi_device *sdev;
2371
2372 __shost_for_each_device(sdev, shost) {
2373 if (channel == sdev_channel(sdev) &&
2374 target == sdev_id(sdev))
2375 __scsi_report_device_reset(sdev, NULL);
2376 }
2377}
2378EXPORT_SYMBOL(scsi_report_device_reset);
2379
2380/**
2381 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2382 * @dev: scsi_device to operate on
2383 * @arg: reset type (see sg.h)
2384 */
2385int
2386scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2387{
2388 struct scsi_cmnd *scmd;
2389 struct Scsi_Host *shost = dev->host;
2390 struct request *rq;
2391 unsigned long flags;
2392 int error = 0, val;
2393 enum scsi_disposition rtn;
2394
2395 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2396 return -EACCES;
2397
2398 error = get_user(val, arg);
2399 if (error)
2400 return error;
2401
2402 if (scsi_autopm_get_host(shost) < 0)
2403 return -EIO;
2404
2405 error = -EIO;
2406 rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2407 shost->hostt->cmd_size, GFP_KERNEL);
2408 if (!rq)
2409 goto out_put_autopm_host;
2410 blk_rq_init(NULL, rq);
2411
2412 scmd = (struct scsi_cmnd *)(rq + 1);
2413 scsi_init_command(dev, scmd);
2414
2415 scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
2416 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2417
2418 scmd->cmd_len = 0;
2419
2420 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2421
2422 spin_lock_irqsave(shost->host_lock, flags);
2423 shost->tmf_in_progress = 1;
2424 spin_unlock_irqrestore(shost->host_lock, flags);
2425
2426 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2427 case SG_SCSI_RESET_NOTHING:
2428 rtn = SUCCESS;
2429 break;
2430 case SG_SCSI_RESET_DEVICE:
2431 rtn = scsi_try_bus_device_reset(scmd);
2432 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2433 break;
2434 fallthrough;
2435 case SG_SCSI_RESET_TARGET:
2436 rtn = scsi_try_target_reset(scmd);
2437 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2438 break;
2439 fallthrough;
2440 case SG_SCSI_RESET_BUS:
2441 rtn = scsi_try_bus_reset(scmd);
2442 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2443 break;
2444 fallthrough;
2445 case SG_SCSI_RESET_HOST:
2446 rtn = scsi_try_host_reset(scmd);
2447 if (rtn == SUCCESS)
2448 break;
2449 fallthrough;
2450 default:
2451 rtn = FAILED;
2452 break;
2453 }
2454
2455 error = (rtn == SUCCESS) ? 0 : -EIO;
2456
2457 spin_lock_irqsave(shost->host_lock, flags);
2458 shost->tmf_in_progress = 0;
2459 spin_unlock_irqrestore(shost->host_lock, flags);
2460
2461 /*
2462 * be sure to wake up anyone who was sleeping or had their queue
2463 * suspended while we performed the TMF.
2464 */
2465 SCSI_LOG_ERROR_RECOVERY(3,
2466 shost_printk(KERN_INFO, shost,
2467 "waking up host to restart after TMF\n"));
2468
2469 wake_up(&shost->host_wait);
2470 scsi_run_host_queues(shost);
2471
2472 kfree(rq);
2473
2474out_put_autopm_host:
2475 scsi_autopm_put_host(shost);
2476 return error;
2477}
2478
2479bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2480 struct scsi_sense_hdr *sshdr)
2481{
2482 return scsi_normalize_sense(cmd->sense_buffer,
2483 SCSI_SENSE_BUFFERSIZE, sshdr);
2484}
2485EXPORT_SYMBOL(scsi_command_normalize_sense);
2486
2487/**
2488 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2489 * @sense_buffer: byte array of sense data
2490 * @sb_len: number of valid bytes in sense_buffer
2491 * @info_out: pointer to 64 integer where 8 or 4 byte information
2492 * field will be placed if found.
2493 *
2494 * Return value:
2495 * true if information field found, false if not found.
2496 */
2497bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2498 u64 *info_out)
2499{
2500 const u8 * ucp;
2501
2502 if (sb_len < 7)
2503 return false;
2504 switch (sense_buffer[0] & 0x7f) {
2505 case 0x70:
2506 case 0x71:
2507 if (sense_buffer[0] & 0x80) {
2508 *info_out = get_unaligned_be32(&sense_buffer[3]);
2509 return true;
2510 }
2511 return false;
2512 case 0x72:
2513 case 0x73:
2514 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2515 0 /* info desc */);
2516 if (ucp && (0xa == ucp[1])) {
2517 *info_out = get_unaligned_be64(&ucp[4]);
2518 return true;
2519 }
2520 return false;
2521 default:
2522 return false;
2523 }
2524}
2525EXPORT_SYMBOL(scsi_get_sense_info_fld);