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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
53static void scsi_eh_done(struct scsi_cmnd *scmd);
54
55/*
56 * These should *probably* be handled by the host itself.
57 * Since it is allowed to sleep, it probably should.
58 */
59#define BUS_RESET_SETTLE_TIME (10)
60#define HOST_RESET_SETTLE_TIME (10)
61
62static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
63static enum scsi_disposition scsi_try_to_abort_cmd(struct scsi_host_template *,
64 struct scsi_cmnd *);
65
66void scsi_eh_wakeup(struct Scsi_Host *shost)
67{
68 lockdep_assert_held(shost->host_lock);
69
70 if (scsi_host_busy(shost) == shost->host_failed) {
71 trace_scsi_eh_wakeup(shost);
72 wake_up_process(shost->ehandler);
73 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
74 "Waking error handler thread\n"));
75 }
76}
77
78/**
79 * scsi_schedule_eh - schedule EH for SCSI host
80 * @shost: SCSI host to invoke error handling on.
81 *
82 * Schedule SCSI EH without scmd.
83 */
84void scsi_schedule_eh(struct Scsi_Host *shost)
85{
86 unsigned long flags;
87
88 spin_lock_irqsave(shost->host_lock, flags);
89
90 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
91 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
92 shost->host_eh_scheduled++;
93 scsi_eh_wakeup(shost);
94 }
95
96 spin_unlock_irqrestore(shost->host_lock, flags);
97}
98EXPORT_SYMBOL_GPL(scsi_schedule_eh);
99
100static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
101{
102 if (!shost->last_reset || shost->eh_deadline == -1)
103 return 0;
104
105 /*
106 * 32bit accesses are guaranteed to be atomic
107 * (on all supported architectures), so instead
108 * of using a spinlock we can as well double check
109 * if eh_deadline has been set to 'off' during the
110 * time_before call.
111 */
112 if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
113 shost->eh_deadline > -1)
114 return 0;
115
116 return 1;
117}
118
119static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
120{
121 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
122 return true;
123
124 return ++cmd->retries <= cmd->allowed;
125}
126
127static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
128{
129 struct scsi_device *sdev = cmd->device;
130 struct Scsi_Host *host = sdev->host;
131
132 if (host->hostt->eh_should_retry_cmd)
133 return host->hostt->eh_should_retry_cmd(cmd);
134
135 return true;
136}
137
138/**
139 * scmd_eh_abort_handler - Handle command aborts
140 * @work: command to be aborted.
141 *
142 * Note: this function must be called only for a command that has timed out.
143 * Because the block layer marks a request as complete before it calls
144 * scsi_times_out(), a .scsi_done() call from the LLD for a command that has
145 * timed out do not have any effect. Hence it is safe to call
146 * scsi_finish_command() from this function.
147 */
148void
149scmd_eh_abort_handler(struct work_struct *work)
150{
151 struct scsi_cmnd *scmd =
152 container_of(work, struct scsi_cmnd, abort_work.work);
153 struct scsi_device *sdev = scmd->device;
154 enum scsi_disposition rtn;
155
156 if (scsi_host_eh_past_deadline(sdev->host)) {
157 SCSI_LOG_ERROR_RECOVERY(3,
158 scmd_printk(KERN_INFO, scmd,
159 "eh timeout, not aborting\n"));
160 } else {
161 SCSI_LOG_ERROR_RECOVERY(3,
162 scmd_printk(KERN_INFO, scmd,
163 "aborting command\n"));
164 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
165 if (rtn == SUCCESS) {
166 set_host_byte(scmd, DID_TIME_OUT);
167 if (scsi_host_eh_past_deadline(sdev->host)) {
168 SCSI_LOG_ERROR_RECOVERY(3,
169 scmd_printk(KERN_INFO, scmd,
170 "eh timeout, not retrying "
171 "aborted command\n"));
172 } else if (!scsi_noretry_cmd(scmd) &&
173 scsi_cmd_retry_allowed(scmd) &&
174 scsi_eh_should_retry_cmd(scmd)) {
175 SCSI_LOG_ERROR_RECOVERY(3,
176 scmd_printk(KERN_WARNING, scmd,
177 "retry aborted command\n"));
178 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
179 return;
180 } else {
181 SCSI_LOG_ERROR_RECOVERY(3,
182 scmd_printk(KERN_WARNING, scmd,
183 "finish aborted command\n"));
184 scsi_finish_command(scmd);
185 return;
186 }
187 } else {
188 SCSI_LOG_ERROR_RECOVERY(3,
189 scmd_printk(KERN_INFO, scmd,
190 "cmd abort %s\n",
191 (rtn == FAST_IO_FAIL) ?
192 "not send" : "failed"));
193 }
194 }
195
196 scsi_eh_scmd_add(scmd);
197}
198
199/**
200 * scsi_abort_command - schedule a command abort
201 * @scmd: scmd to abort.
202 *
203 * We only need to abort commands after a command timeout
204 */
205static int
206scsi_abort_command(struct scsi_cmnd *scmd)
207{
208 struct scsi_device *sdev = scmd->device;
209 struct Scsi_Host *shost = sdev->host;
210 unsigned long flags;
211
212 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
213 /*
214 * Retry after abort failed, escalate to next level.
215 */
216 SCSI_LOG_ERROR_RECOVERY(3,
217 scmd_printk(KERN_INFO, scmd,
218 "previous abort failed\n"));
219 BUG_ON(delayed_work_pending(&scmd->abort_work));
220 return FAILED;
221 }
222
223 spin_lock_irqsave(shost->host_lock, flags);
224 if (shost->eh_deadline != -1 && !shost->last_reset)
225 shost->last_reset = jiffies;
226 spin_unlock_irqrestore(shost->host_lock, flags);
227
228 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
229 SCSI_LOG_ERROR_RECOVERY(3,
230 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
231 queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
232 return SUCCESS;
233}
234
235/**
236 * scsi_eh_reset - call into ->eh_action to reset internal counters
237 * @scmd: scmd to run eh on.
238 *
239 * The scsi driver might be carrying internal state about the
240 * devices, so we need to call into the driver to reset the
241 * internal state once the error handler is started.
242 */
243static void scsi_eh_reset(struct scsi_cmnd *scmd)
244{
245 if (!blk_rq_is_passthrough(scmd->request)) {
246 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
247 if (sdrv->eh_reset)
248 sdrv->eh_reset(scmd);
249 }
250}
251
252static void scsi_eh_inc_host_failed(struct rcu_head *head)
253{
254 struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
255 struct Scsi_Host *shost = scmd->device->host;
256 unsigned long flags;
257
258 spin_lock_irqsave(shost->host_lock, flags);
259 shost->host_failed++;
260 scsi_eh_wakeup(shost);
261 spin_unlock_irqrestore(shost->host_lock, flags);
262}
263
264/**
265 * scsi_eh_scmd_add - add scsi cmd to error handling.
266 * @scmd: scmd to run eh on.
267 */
268void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
269{
270 struct Scsi_Host *shost = scmd->device->host;
271 unsigned long flags;
272 int ret;
273
274 WARN_ON_ONCE(!shost->ehandler);
275
276 spin_lock_irqsave(shost->host_lock, flags);
277 if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
278 ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
279 WARN_ON_ONCE(ret);
280 }
281 if (shost->eh_deadline != -1 && !shost->last_reset)
282 shost->last_reset = jiffies;
283
284 scsi_eh_reset(scmd);
285 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
286 spin_unlock_irqrestore(shost->host_lock, flags);
287 /*
288 * Ensure that all tasks observe the host state change before the
289 * host_failed change.
290 */
291 call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
292}
293
294/**
295 * scsi_times_out - Timeout function for normal scsi commands.
296 * @req: request that is timing out.
297 *
298 * Notes:
299 * We do not need to lock this. There is the potential for a race
300 * only in that the normal completion handling might run, but if the
301 * normal completion function determines that the timer has already
302 * fired, then it mustn't do anything.
303 */
304enum blk_eh_timer_return scsi_times_out(struct request *req)
305{
306 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
307 enum blk_eh_timer_return rtn = BLK_EH_DONE;
308 struct Scsi_Host *host = scmd->device->host;
309
310 trace_scsi_dispatch_cmd_timeout(scmd);
311 scsi_log_completion(scmd, TIMEOUT_ERROR);
312
313 if (host->eh_deadline != -1 && !host->last_reset)
314 host->last_reset = jiffies;
315
316 if (host->hostt->eh_timed_out)
317 rtn = host->hostt->eh_timed_out(scmd);
318
319 if (rtn == BLK_EH_DONE) {
320 /*
321 * Set the command to complete first in order to prevent a real
322 * completion from releasing the command while error handling
323 * is using it. If the command was already completed, then the
324 * lower level driver beat the timeout handler, and it is safe
325 * to return without escalating error recovery.
326 *
327 * If timeout handling lost the race to a real completion, the
328 * block layer may ignore that due to a fake timeout injection,
329 * so return RESET_TIMER to allow error handling another shot
330 * at this command.
331 */
332 if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
333 return BLK_EH_RESET_TIMER;
334 if (scsi_abort_command(scmd) != SUCCESS) {
335 set_host_byte(scmd, DID_TIME_OUT);
336 scsi_eh_scmd_add(scmd);
337 }
338 }
339
340 return rtn;
341}
342
343/**
344 * scsi_block_when_processing_errors - Prevent cmds from being queued.
345 * @sdev: Device on which we are performing recovery.
346 *
347 * Description:
348 * We block until the host is out of error recovery, and then check to
349 * see whether the host or the device is offline.
350 *
351 * Return value:
352 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
353 */
354int scsi_block_when_processing_errors(struct scsi_device *sdev)
355{
356 int online;
357
358 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
359
360 online = scsi_device_online(sdev);
361
362 return online;
363}
364EXPORT_SYMBOL(scsi_block_when_processing_errors);
365
366#ifdef CONFIG_SCSI_LOGGING
367/**
368 * scsi_eh_prt_fail_stats - Log info on failures.
369 * @shost: scsi host being recovered.
370 * @work_q: Queue of scsi cmds to process.
371 */
372static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
373 struct list_head *work_q)
374{
375 struct scsi_cmnd *scmd;
376 struct scsi_device *sdev;
377 int total_failures = 0;
378 int cmd_failed = 0;
379 int cmd_cancel = 0;
380 int devices_failed = 0;
381
382 shost_for_each_device(sdev, shost) {
383 list_for_each_entry(scmd, work_q, eh_entry) {
384 if (scmd->device == sdev) {
385 ++total_failures;
386 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
387 ++cmd_cancel;
388 else
389 ++cmd_failed;
390 }
391 }
392
393 if (cmd_cancel || cmd_failed) {
394 SCSI_LOG_ERROR_RECOVERY(3,
395 shost_printk(KERN_INFO, shost,
396 "%s: cmds failed: %d, cancel: %d\n",
397 __func__, cmd_failed,
398 cmd_cancel));
399 cmd_cancel = 0;
400 cmd_failed = 0;
401 ++devices_failed;
402 }
403 }
404
405 SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
406 "Total of %d commands on %d"
407 " devices require eh work\n",
408 total_failures, devices_failed));
409}
410#endif
411
412 /**
413 * scsi_report_lun_change - Set flag on all *other* devices on the same target
414 * to indicate that a UNIT ATTENTION is expected.
415 * @sdev: Device reporting the UNIT ATTENTION
416 */
417static void scsi_report_lun_change(struct scsi_device *sdev)
418{
419 sdev->sdev_target->expecting_lun_change = 1;
420}
421
422/**
423 * scsi_report_sense - Examine scsi sense information and log messages for
424 * certain conditions, also issue uevents for some of them.
425 * @sdev: Device reporting the sense code
426 * @sshdr: sshdr to be examined
427 */
428static void scsi_report_sense(struct scsi_device *sdev,
429 struct scsi_sense_hdr *sshdr)
430{
431 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
432
433 if (sshdr->sense_key == UNIT_ATTENTION) {
434 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
435 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
436 sdev_printk(KERN_WARNING, sdev,
437 "Inquiry data has changed");
438 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
439 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
440 scsi_report_lun_change(sdev);
441 sdev_printk(KERN_WARNING, sdev,
442 "Warning! Received an indication that the "
443 "LUN assignments on this target have "
444 "changed. The Linux SCSI layer does not "
445 "automatically remap LUN assignments.\n");
446 } else if (sshdr->asc == 0x3f)
447 sdev_printk(KERN_WARNING, sdev,
448 "Warning! Received an indication that the "
449 "operating parameters on this target have "
450 "changed. The Linux SCSI layer does not "
451 "automatically adjust these parameters.\n");
452
453 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
454 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
455 sdev_printk(KERN_WARNING, sdev,
456 "Warning! Received an indication that the "
457 "LUN reached a thin provisioning soft "
458 "threshold.\n");
459 }
460
461 if (sshdr->asc == 0x29) {
462 evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
463 sdev_printk(KERN_WARNING, sdev,
464 "Power-on or device reset occurred\n");
465 }
466
467 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
468 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
469 sdev_printk(KERN_WARNING, sdev,
470 "Mode parameters changed");
471 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
472 evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
473 sdev_printk(KERN_WARNING, sdev,
474 "Asymmetric access state changed");
475 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
476 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
477 sdev_printk(KERN_WARNING, sdev,
478 "Capacity data has changed");
479 } else if (sshdr->asc == 0x2a)
480 sdev_printk(KERN_WARNING, sdev,
481 "Parameters changed");
482 }
483
484 if (evt_type != SDEV_EVT_MAXBITS) {
485 set_bit(evt_type, sdev->pending_events);
486 schedule_work(&sdev->event_work);
487 }
488}
489
490/**
491 * scsi_check_sense - Examine scsi cmd sense
492 * @scmd: Cmd to have sense checked.
493 *
494 * Return value:
495 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
496 *
497 * Notes:
498 * When a deferred error is detected the current command has
499 * not been executed and needs retrying.
500 */
501enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
502{
503 struct scsi_device *sdev = scmd->device;
504 struct scsi_sense_hdr sshdr;
505
506 if (! scsi_command_normalize_sense(scmd, &sshdr))
507 return FAILED; /* no valid sense data */
508
509 scsi_report_sense(sdev, &sshdr);
510
511 if (scsi_sense_is_deferred(&sshdr))
512 return NEEDS_RETRY;
513
514 if (sdev->handler && sdev->handler->check_sense) {
515 enum scsi_disposition rc;
516
517 rc = sdev->handler->check_sense(sdev, &sshdr);
518 if (rc != SCSI_RETURN_NOT_HANDLED)
519 return rc;
520 /* handler does not care. Drop down to default handling */
521 }
522
523 if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
524 /*
525 * nasty: for mid-layer issued TURs, we need to return the
526 * actual sense data without any recovery attempt. For eh
527 * issued ones, we need to try to recover and interpret
528 */
529 return SUCCESS;
530
531 /*
532 * Previous logic looked for FILEMARK, EOM or ILI which are
533 * mainly associated with tapes and returned SUCCESS.
534 */
535 if (sshdr.response_code == 0x70) {
536 /* fixed format */
537 if (scmd->sense_buffer[2] & 0xe0)
538 return SUCCESS;
539 } else {
540 /*
541 * descriptor format: look for "stream commands sense data
542 * descriptor" (see SSC-3). Assume single sense data
543 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
544 */
545 if ((sshdr.additional_length > 3) &&
546 (scmd->sense_buffer[8] == 0x4) &&
547 (scmd->sense_buffer[11] & 0xe0))
548 return SUCCESS;
549 }
550
551 switch (sshdr.sense_key) {
552 case NO_SENSE:
553 return SUCCESS;
554 case RECOVERED_ERROR:
555 return /* soft_error */ SUCCESS;
556
557 case ABORTED_COMMAND:
558 if (sshdr.asc == 0x10) /* DIF */
559 return SUCCESS;
560
561 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
562 return ADD_TO_MLQUEUE;
563 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
564 sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
565 return ADD_TO_MLQUEUE;
566
567 return NEEDS_RETRY;
568 case NOT_READY:
569 case UNIT_ATTENTION:
570 /*
571 * if we are expecting a cc/ua because of a bus reset that we
572 * performed, treat this just as a retry. otherwise this is
573 * information that we should pass up to the upper-level driver
574 * so that we can deal with it there.
575 */
576 if (scmd->device->expecting_cc_ua) {
577 /*
578 * Because some device does not queue unit
579 * attentions correctly, we carefully check
580 * additional sense code and qualifier so as
581 * not to squash media change unit attention.
582 */
583 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
584 scmd->device->expecting_cc_ua = 0;
585 return NEEDS_RETRY;
586 }
587 }
588 /*
589 * we might also expect a cc/ua if another LUN on the target
590 * reported a UA with an ASC/ASCQ of 3F 0E -
591 * REPORTED LUNS DATA HAS CHANGED.
592 */
593 if (scmd->device->sdev_target->expecting_lun_change &&
594 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
595 return NEEDS_RETRY;
596 /*
597 * if the device is in the process of becoming ready, we
598 * should retry.
599 */
600 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
601 return NEEDS_RETRY;
602 /*
603 * if the device is not started, we need to wake
604 * the error handler to start the motor
605 */
606 if (scmd->device->allow_restart &&
607 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
608 return FAILED;
609 /*
610 * Pass the UA upwards for a determination in the completion
611 * functions.
612 */
613 return SUCCESS;
614
615 /* these are not supported */
616 case DATA_PROTECT:
617 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
618 /* Thin provisioning hard threshold reached */
619 set_host_byte(scmd, DID_ALLOC_FAILURE);
620 return SUCCESS;
621 }
622 fallthrough;
623 case COPY_ABORTED:
624 case VOLUME_OVERFLOW:
625 case MISCOMPARE:
626 case BLANK_CHECK:
627 set_host_byte(scmd, DID_TARGET_FAILURE);
628 return SUCCESS;
629
630 case MEDIUM_ERROR:
631 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
632 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
633 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
634 set_host_byte(scmd, DID_MEDIUM_ERROR);
635 return SUCCESS;
636 }
637 return NEEDS_RETRY;
638
639 case HARDWARE_ERROR:
640 if (scmd->device->retry_hwerror)
641 return ADD_TO_MLQUEUE;
642 else
643 set_host_byte(scmd, DID_TARGET_FAILURE);
644 fallthrough;
645
646 case ILLEGAL_REQUEST:
647 if (sshdr.asc == 0x20 || /* Invalid command operation code */
648 sshdr.asc == 0x21 || /* Logical block address out of range */
649 sshdr.asc == 0x22 || /* Invalid function */
650 sshdr.asc == 0x24 || /* Invalid field in cdb */
651 sshdr.asc == 0x26 || /* Parameter value invalid */
652 sshdr.asc == 0x27) { /* Write protected */
653 set_host_byte(scmd, DID_TARGET_FAILURE);
654 }
655 return SUCCESS;
656
657 default:
658 return SUCCESS;
659 }
660}
661EXPORT_SYMBOL_GPL(scsi_check_sense);
662
663static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
664{
665 struct scsi_host_template *sht = sdev->host->hostt;
666 struct scsi_device *tmp_sdev;
667
668 if (!sht->track_queue_depth ||
669 sdev->queue_depth >= sdev->max_queue_depth)
670 return;
671
672 if (time_before(jiffies,
673 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
674 return;
675
676 if (time_before(jiffies,
677 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
678 return;
679
680 /*
681 * Walk all devices of a target and do
682 * ramp up on them.
683 */
684 shost_for_each_device(tmp_sdev, sdev->host) {
685 if (tmp_sdev->channel != sdev->channel ||
686 tmp_sdev->id != sdev->id ||
687 tmp_sdev->queue_depth == sdev->max_queue_depth)
688 continue;
689
690 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
691 sdev->last_queue_ramp_up = jiffies;
692 }
693}
694
695static void scsi_handle_queue_full(struct scsi_device *sdev)
696{
697 struct scsi_host_template *sht = sdev->host->hostt;
698 struct scsi_device *tmp_sdev;
699
700 if (!sht->track_queue_depth)
701 return;
702
703 shost_for_each_device(tmp_sdev, sdev->host) {
704 if (tmp_sdev->channel != sdev->channel ||
705 tmp_sdev->id != sdev->id)
706 continue;
707 /*
708 * We do not know the number of commands that were at
709 * the device when we got the queue full so we start
710 * from the highest possible value and work our way down.
711 */
712 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
713 }
714}
715
716/**
717 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
718 * @scmd: SCSI cmd to examine.
719 *
720 * Notes:
721 * This is *only* called when we are examining the status of commands
722 * queued during error recovery. the main difference here is that we
723 * don't allow for the possibility of retries here, and we are a lot
724 * more restrictive about what we consider acceptable.
725 */
726static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
727{
728 /*
729 * first check the host byte, to see if there is anything in there
730 * that would indicate what we need to do.
731 */
732 if (host_byte(scmd->result) == DID_RESET) {
733 /*
734 * rats. we are already in the error handler, so we now
735 * get to try and figure out what to do next. if the sense
736 * is valid, we have a pretty good idea of what to do.
737 * if not, we mark it as FAILED.
738 */
739 return scsi_check_sense(scmd);
740 }
741 if (host_byte(scmd->result) != DID_OK)
742 return FAILED;
743
744 /*
745 * now, check the status byte to see if this indicates
746 * anything special.
747 */
748 switch (get_status_byte(scmd)) {
749 case SAM_STAT_GOOD:
750 scsi_handle_queue_ramp_up(scmd->device);
751 fallthrough;
752 case SAM_STAT_COMMAND_TERMINATED:
753 return SUCCESS;
754 case SAM_STAT_CHECK_CONDITION:
755 return scsi_check_sense(scmd);
756 case SAM_STAT_CONDITION_MET:
757 case SAM_STAT_INTERMEDIATE:
758 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
759 /*
760 * who knows? FIXME(eric)
761 */
762 return SUCCESS;
763 case SAM_STAT_RESERVATION_CONFLICT:
764 if (scmd->cmnd[0] == TEST_UNIT_READY)
765 /* it is a success, we probed the device and
766 * found it */
767 return SUCCESS;
768 /* otherwise, we failed to send the command */
769 return FAILED;
770 case SAM_STAT_TASK_SET_FULL:
771 scsi_handle_queue_full(scmd->device);
772 fallthrough;
773 case SAM_STAT_BUSY:
774 return NEEDS_RETRY;
775 default:
776 return FAILED;
777 }
778 return FAILED;
779}
780
781/**
782 * scsi_eh_done - Completion function for error handling.
783 * @scmd: Cmd that is done.
784 */
785static void scsi_eh_done(struct scsi_cmnd *scmd)
786{
787 struct completion *eh_action;
788
789 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
790 "%s result: %x\n", __func__, scmd->result));
791
792 eh_action = scmd->device->host->eh_action;
793 if (eh_action)
794 complete(eh_action);
795}
796
797/**
798 * scsi_try_host_reset - ask host adapter to reset itself
799 * @scmd: SCSI cmd to send host reset.
800 */
801static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
802{
803 unsigned long flags;
804 enum scsi_disposition rtn;
805 struct Scsi_Host *host = scmd->device->host;
806 struct scsi_host_template *hostt = host->hostt;
807
808 SCSI_LOG_ERROR_RECOVERY(3,
809 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
810
811 if (!hostt->eh_host_reset_handler)
812 return FAILED;
813
814 rtn = hostt->eh_host_reset_handler(scmd);
815
816 if (rtn == SUCCESS) {
817 if (!hostt->skip_settle_delay)
818 ssleep(HOST_RESET_SETTLE_TIME);
819 spin_lock_irqsave(host->host_lock, flags);
820 scsi_report_bus_reset(host, scmd_channel(scmd));
821 spin_unlock_irqrestore(host->host_lock, flags);
822 }
823
824 return rtn;
825}
826
827/**
828 * scsi_try_bus_reset - ask host to perform a bus reset
829 * @scmd: SCSI cmd to send bus reset.
830 */
831static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
832{
833 unsigned long flags;
834 enum scsi_disposition rtn;
835 struct Scsi_Host *host = scmd->device->host;
836 struct scsi_host_template *hostt = host->hostt;
837
838 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
839 "%s: Snd Bus RST\n", __func__));
840
841 if (!hostt->eh_bus_reset_handler)
842 return FAILED;
843
844 rtn = hostt->eh_bus_reset_handler(scmd);
845
846 if (rtn == SUCCESS) {
847 if (!hostt->skip_settle_delay)
848 ssleep(BUS_RESET_SETTLE_TIME);
849 spin_lock_irqsave(host->host_lock, flags);
850 scsi_report_bus_reset(host, scmd_channel(scmd));
851 spin_unlock_irqrestore(host->host_lock, flags);
852 }
853
854 return rtn;
855}
856
857static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
858{
859 sdev->was_reset = 1;
860 sdev->expecting_cc_ua = 1;
861}
862
863/**
864 * scsi_try_target_reset - Ask host to perform a target reset
865 * @scmd: SCSI cmd used to send a target reset
866 *
867 * Notes:
868 * There is no timeout for this operation. if this operation is
869 * unreliable for a given host, then the host itself needs to put a
870 * timer on it, and set the host back to a consistent state prior to
871 * returning.
872 */
873static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
874{
875 unsigned long flags;
876 enum scsi_disposition rtn;
877 struct Scsi_Host *host = scmd->device->host;
878 struct scsi_host_template *hostt = host->hostt;
879
880 if (!hostt->eh_target_reset_handler)
881 return FAILED;
882
883 rtn = hostt->eh_target_reset_handler(scmd);
884 if (rtn == SUCCESS) {
885 spin_lock_irqsave(host->host_lock, flags);
886 __starget_for_each_device(scsi_target(scmd->device), NULL,
887 __scsi_report_device_reset);
888 spin_unlock_irqrestore(host->host_lock, flags);
889 }
890
891 return rtn;
892}
893
894/**
895 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
896 * @scmd: SCSI cmd used to send BDR
897 *
898 * Notes:
899 * There is no timeout for this operation. if this operation is
900 * unreliable for a given host, then the host itself needs to put a
901 * timer on it, and set the host back to a consistent state prior to
902 * returning.
903 */
904static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
905{
906 enum scsi_disposition rtn;
907 struct scsi_host_template *hostt = scmd->device->host->hostt;
908
909 if (!hostt->eh_device_reset_handler)
910 return FAILED;
911
912 rtn = hostt->eh_device_reset_handler(scmd);
913 if (rtn == SUCCESS)
914 __scsi_report_device_reset(scmd->device, NULL);
915 return rtn;
916}
917
918/**
919 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
920 * @hostt: SCSI driver host template
921 * @scmd: SCSI cmd used to send a target reset
922 *
923 * Return value:
924 * SUCCESS, FAILED, or FAST_IO_FAIL
925 *
926 * Notes:
927 * SUCCESS does not necessarily indicate that the command
928 * has been aborted; it only indicates that the LLDDs
929 * has cleared all references to that command.
930 * LLDDs should return FAILED only if an abort was required
931 * but could not be executed. LLDDs should return FAST_IO_FAIL
932 * if the device is temporarily unavailable (eg due to a
933 * link down on FibreChannel)
934 */
935static enum scsi_disposition
936scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
937{
938 if (!hostt->eh_abort_handler)
939 return FAILED;
940
941 return hostt->eh_abort_handler(scmd);
942}
943
944static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
945{
946 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
947 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
948 if (scsi_try_target_reset(scmd) != SUCCESS)
949 if (scsi_try_bus_reset(scmd) != SUCCESS)
950 scsi_try_host_reset(scmd);
951}
952
953/**
954 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
955 * @scmd: SCSI command structure to hijack
956 * @ses: structure to save restore information
957 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
958 * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
959 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
960 *
961 * This function is used to save a scsi command information before re-execution
962 * as part of the error recovery process. If @sense_bytes is 0 the command
963 * sent must be one that does not transfer any data. If @sense_bytes != 0
964 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
965 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
966 */
967void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
968 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
969{
970 struct scsi_device *sdev = scmd->device;
971
972 /*
973 * We need saved copies of a number of fields - this is because
974 * error handling may need to overwrite these with different values
975 * to run different commands, and once error handling is complete,
976 * we will need to restore these values prior to running the actual
977 * command.
978 */
979 ses->cmd_len = scmd->cmd_len;
980 ses->cmnd = scmd->cmnd;
981 ses->data_direction = scmd->sc_data_direction;
982 ses->sdb = scmd->sdb;
983 ses->result = scmd->result;
984 ses->resid_len = scmd->req.resid_len;
985 ses->underflow = scmd->underflow;
986 ses->prot_op = scmd->prot_op;
987 ses->eh_eflags = scmd->eh_eflags;
988
989 scmd->prot_op = SCSI_PROT_NORMAL;
990 scmd->eh_eflags = 0;
991 scmd->cmnd = ses->eh_cmnd;
992 memset(scmd->cmnd, 0, BLK_MAX_CDB);
993 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
994 scmd->result = 0;
995 scmd->req.resid_len = 0;
996
997 if (sense_bytes) {
998 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
999 sense_bytes);
1000 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1001 scmd->sdb.length);
1002 scmd->sdb.table.sgl = &ses->sense_sgl;
1003 scmd->sc_data_direction = DMA_FROM_DEVICE;
1004 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1005 scmd->cmnd[0] = REQUEST_SENSE;
1006 scmd->cmnd[4] = scmd->sdb.length;
1007 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1008 } else {
1009 scmd->sc_data_direction = DMA_NONE;
1010 if (cmnd) {
1011 BUG_ON(cmnd_size > BLK_MAX_CDB);
1012 memcpy(scmd->cmnd, cmnd, cmnd_size);
1013 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1014 }
1015 }
1016
1017 scmd->underflow = 0;
1018
1019 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1020 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1021 (sdev->lun << 5 & 0xe0);
1022
1023 /*
1024 * Zero the sense buffer. The scsi spec mandates that any
1025 * untransferred sense data should be interpreted as being zero.
1026 */
1027 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1028}
1029EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1030
1031/**
1032 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
1033 * @scmd: SCSI command structure to restore
1034 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
1035 *
1036 * Undo any damage done by above scsi_eh_prep_cmnd().
1037 */
1038void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1039{
1040 /*
1041 * Restore original data
1042 */
1043 scmd->cmd_len = ses->cmd_len;
1044 scmd->cmnd = ses->cmnd;
1045 scmd->sc_data_direction = ses->data_direction;
1046 scmd->sdb = ses->sdb;
1047 scmd->result = ses->result;
1048 scmd->req.resid_len = ses->resid_len;
1049 scmd->underflow = ses->underflow;
1050 scmd->prot_op = ses->prot_op;
1051 scmd->eh_eflags = ses->eh_eflags;
1052}
1053EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1054
1055/**
1056 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1057 * @scmd: SCSI command structure to hijack
1058 * @cmnd: CDB to send
1059 * @cmnd_size: size in bytes of @cmnd
1060 * @timeout: timeout for this request
1061 * @sense_bytes: size of sense data to copy or 0
1062 *
1063 * This function is used to send a scsi command down to a target device
1064 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1065 *
1066 * Return value:
1067 * SUCCESS or FAILED or NEEDS_RETRY
1068 */
1069static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1070 unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1071{
1072 struct scsi_device *sdev = scmd->device;
1073 struct Scsi_Host *shost = sdev->host;
1074 DECLARE_COMPLETION_ONSTACK(done);
1075 unsigned long timeleft = timeout, delay;
1076 struct scsi_eh_save ses;
1077 const unsigned long stall_for = msecs_to_jiffies(100);
1078 int rtn;
1079
1080retry:
1081 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1082 shost->eh_action = &done;
1083
1084 scsi_log_send(scmd);
1085 scmd->scsi_done = scsi_eh_done;
1086
1087 /*
1088 * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1089 * change the SCSI device state after we have examined it and before
1090 * .queuecommand() is called.
1091 */
1092 mutex_lock(&sdev->state_mutex);
1093 while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1094 mutex_unlock(&sdev->state_mutex);
1095 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1096 "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1097 SDEV_BLOCK));
1098 delay = min(timeleft, stall_for);
1099 timeleft -= delay;
1100 msleep(jiffies_to_msecs(delay));
1101 mutex_lock(&sdev->state_mutex);
1102 }
1103 if (sdev->sdev_state != SDEV_BLOCK)
1104 rtn = shost->hostt->queuecommand(shost, scmd);
1105 else
1106 rtn = FAILED;
1107 mutex_unlock(&sdev->state_mutex);
1108
1109 if (rtn) {
1110 if (timeleft > stall_for) {
1111 scsi_eh_restore_cmnd(scmd, &ses);
1112 timeleft -= stall_for;
1113 msleep(jiffies_to_msecs(stall_for));
1114 goto retry;
1115 }
1116 /* signal not to enter either branch of the if () below */
1117 timeleft = 0;
1118 rtn = FAILED;
1119 } else {
1120 timeleft = wait_for_completion_timeout(&done, timeout);
1121 rtn = SUCCESS;
1122 }
1123
1124 shost->eh_action = NULL;
1125
1126 scsi_log_completion(scmd, rtn);
1127
1128 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1129 "%s timeleft: %ld\n",
1130 __func__, timeleft));
1131
1132 /*
1133 * If there is time left scsi_eh_done got called, and we will examine
1134 * the actual status codes to see whether the command actually did
1135 * complete normally, else if we have a zero return and no time left,
1136 * the command must still be pending, so abort it and return FAILED.
1137 * If we never actually managed to issue the command, because
1138 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1139 * value above (so don't execute either branch of the if)
1140 */
1141 if (timeleft) {
1142 rtn = scsi_eh_completed_normally(scmd);
1143 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1144 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1145
1146 switch (rtn) {
1147 case SUCCESS:
1148 case NEEDS_RETRY:
1149 case FAILED:
1150 break;
1151 case ADD_TO_MLQUEUE:
1152 rtn = NEEDS_RETRY;
1153 break;
1154 default:
1155 rtn = FAILED;
1156 break;
1157 }
1158 } else if (rtn != FAILED) {
1159 scsi_abort_eh_cmnd(scmd);
1160 rtn = FAILED;
1161 }
1162
1163 scsi_eh_restore_cmnd(scmd, &ses);
1164
1165 return rtn;
1166}
1167
1168/**
1169 * scsi_request_sense - Request sense data from a particular target.
1170 * @scmd: SCSI cmd for request sense.
1171 *
1172 * Notes:
1173 * Some hosts automatically obtain this information, others require
1174 * that we obtain it on our own. This function will *not* return until
1175 * the command either times out, or it completes.
1176 */
1177static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1178{
1179 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1180}
1181
1182static enum scsi_disposition
1183scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1184{
1185 if (!blk_rq_is_passthrough(scmd->request)) {
1186 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1187 if (sdrv->eh_action)
1188 rtn = sdrv->eh_action(scmd, rtn);
1189 }
1190 return rtn;
1191}
1192
1193/**
1194 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1195 * @scmd: Original SCSI cmd that eh has finished.
1196 * @done_q: Queue for processed commands.
1197 *
1198 * Notes:
1199 * We don't want to use the normal command completion while we are are
1200 * still handling errors - it may cause other commands to be queued,
1201 * and that would disturb what we are doing. Thus we really want to
1202 * keep a list of pending commands for final completion, and once we
1203 * are ready to leave error handling we handle completion for real.
1204 */
1205void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1206{
1207 list_move_tail(&scmd->eh_entry, done_q);
1208}
1209EXPORT_SYMBOL(scsi_eh_finish_cmd);
1210
1211/**
1212 * scsi_eh_get_sense - Get device sense data.
1213 * @work_q: Queue of commands to process.
1214 * @done_q: Queue of processed commands.
1215 *
1216 * Description:
1217 * See if we need to request sense information. if so, then get it
1218 * now, so we have a better idea of what to do.
1219 *
1220 * Notes:
1221 * This has the unfortunate side effect that if a shost adapter does
1222 * not automatically request sense information, we end up shutting
1223 * it down before we request it.
1224 *
1225 * All drivers should request sense information internally these days,
1226 * so for now all I have to say is tough noogies if you end up in here.
1227 *
1228 * XXX: Long term this code should go away, but that needs an audit of
1229 * all LLDDs first.
1230 */
1231int scsi_eh_get_sense(struct list_head *work_q,
1232 struct list_head *done_q)
1233{
1234 struct scsi_cmnd *scmd, *next;
1235 struct Scsi_Host *shost;
1236 enum scsi_disposition rtn;
1237
1238 /*
1239 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1240 * should not get sense.
1241 */
1242 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1243 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1244 SCSI_SENSE_VALID(scmd))
1245 continue;
1246
1247 shost = scmd->device->host;
1248 if (scsi_host_eh_past_deadline(shost)) {
1249 SCSI_LOG_ERROR_RECOVERY(3,
1250 scmd_printk(KERN_INFO, scmd,
1251 "%s: skip request sense, past eh deadline\n",
1252 current->comm));
1253 break;
1254 }
1255 if (!scsi_status_is_check_condition(scmd->result))
1256 /*
1257 * don't request sense if there's no check condition
1258 * status because the error we're processing isn't one
1259 * that has a sense code (and some devices get
1260 * confused by sense requests out of the blue)
1261 */
1262 continue;
1263
1264 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1265 "%s: requesting sense\n",
1266 current->comm));
1267 rtn = scsi_request_sense(scmd);
1268 if (rtn != SUCCESS)
1269 continue;
1270
1271 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1272 "sense requested, result %x\n", scmd->result));
1273 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1274
1275 rtn = scsi_decide_disposition(scmd);
1276
1277 /*
1278 * if the result was normal, then just pass it along to the
1279 * upper level.
1280 */
1281 if (rtn == SUCCESS)
1282 /*
1283 * We don't want this command reissued, just finished
1284 * with the sense data, so set retries to the max
1285 * allowed to ensure it won't get reissued. If the user
1286 * has requested infinite retries, we also want to
1287 * finish this command, so force completion by setting
1288 * retries and allowed to the same value.
1289 */
1290 if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1291 scmd->retries = scmd->allowed = 1;
1292 else
1293 scmd->retries = scmd->allowed;
1294 else if (rtn != NEEDS_RETRY)
1295 continue;
1296
1297 scsi_eh_finish_cmd(scmd, done_q);
1298 }
1299
1300 return list_empty(work_q);
1301}
1302EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1303
1304/**
1305 * scsi_eh_tur - Send TUR to device.
1306 * @scmd: &scsi_cmnd to send TUR
1307 *
1308 * Return value:
1309 * 0 - Device is ready. 1 - Device NOT ready.
1310 */
1311static int scsi_eh_tur(struct scsi_cmnd *scmd)
1312{
1313 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1314 int retry_cnt = 1;
1315 enum scsi_disposition rtn;
1316
1317retry_tur:
1318 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1319 scmd->device->eh_timeout, 0);
1320
1321 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1322 "%s return: %x\n", __func__, rtn));
1323
1324 switch (rtn) {
1325 case NEEDS_RETRY:
1326 if (retry_cnt--)
1327 goto retry_tur;
1328 fallthrough;
1329 case SUCCESS:
1330 return 0;
1331 default:
1332 return 1;
1333 }
1334}
1335
1336/**
1337 * scsi_eh_test_devices - check if devices are responding from error recovery.
1338 * @cmd_list: scsi commands in error recovery.
1339 * @work_q: queue for commands which still need more error recovery
1340 * @done_q: queue for commands which are finished
1341 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1342 *
1343 * Decription:
1344 * Tests if devices are in a working state. Commands to devices now in
1345 * a working state are sent to the done_q while commands to devices which
1346 * are still failing to respond are returned to the work_q for more
1347 * processing.
1348 **/
1349static int scsi_eh_test_devices(struct list_head *cmd_list,
1350 struct list_head *work_q,
1351 struct list_head *done_q, int try_stu)
1352{
1353 struct scsi_cmnd *scmd, *next;
1354 struct scsi_device *sdev;
1355 int finish_cmds;
1356
1357 while (!list_empty(cmd_list)) {
1358 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1359 sdev = scmd->device;
1360
1361 if (!try_stu) {
1362 if (scsi_host_eh_past_deadline(sdev->host)) {
1363 /* Push items back onto work_q */
1364 list_splice_init(cmd_list, work_q);
1365 SCSI_LOG_ERROR_RECOVERY(3,
1366 sdev_printk(KERN_INFO, sdev,
1367 "%s: skip test device, past eh deadline",
1368 current->comm));
1369 break;
1370 }
1371 }
1372
1373 finish_cmds = !scsi_device_online(scmd->device) ||
1374 (try_stu && !scsi_eh_try_stu(scmd) &&
1375 !scsi_eh_tur(scmd)) ||
1376 !scsi_eh_tur(scmd);
1377
1378 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1379 if (scmd->device == sdev) {
1380 if (finish_cmds &&
1381 (try_stu ||
1382 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1383 scsi_eh_finish_cmd(scmd, done_q);
1384 else
1385 list_move_tail(&scmd->eh_entry, work_q);
1386 }
1387 }
1388 return list_empty(work_q);
1389}
1390
1391/**
1392 * scsi_eh_try_stu - Send START_UNIT to device.
1393 * @scmd: &scsi_cmnd to send START_UNIT
1394 *
1395 * Return value:
1396 * 0 - Device is ready. 1 - Device NOT ready.
1397 */
1398static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1399{
1400 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1401
1402 if (scmd->device->allow_restart) {
1403 int i;
1404 enum scsi_disposition rtn = NEEDS_RETRY;
1405
1406 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1407 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1408
1409 if (rtn == SUCCESS)
1410 return 0;
1411 }
1412
1413 return 1;
1414}
1415
1416 /**
1417 * scsi_eh_stu - send START_UNIT if needed
1418 * @shost: &scsi host being recovered.
1419 * @work_q: &list_head for pending commands.
1420 * @done_q: &list_head for processed commands.
1421 *
1422 * Notes:
1423 * If commands are failing due to not ready, initializing command required,
1424 * try revalidating the device, which will end up sending a start unit.
1425 */
1426static int scsi_eh_stu(struct Scsi_Host *shost,
1427 struct list_head *work_q,
1428 struct list_head *done_q)
1429{
1430 struct scsi_cmnd *scmd, *stu_scmd, *next;
1431 struct scsi_device *sdev;
1432
1433 shost_for_each_device(sdev, shost) {
1434 if (scsi_host_eh_past_deadline(shost)) {
1435 SCSI_LOG_ERROR_RECOVERY(3,
1436 sdev_printk(KERN_INFO, sdev,
1437 "%s: skip START_UNIT, past eh deadline\n",
1438 current->comm));
1439 scsi_device_put(sdev);
1440 break;
1441 }
1442 stu_scmd = NULL;
1443 list_for_each_entry(scmd, work_q, eh_entry)
1444 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1445 scsi_check_sense(scmd) == FAILED ) {
1446 stu_scmd = scmd;
1447 break;
1448 }
1449
1450 if (!stu_scmd)
1451 continue;
1452
1453 SCSI_LOG_ERROR_RECOVERY(3,
1454 sdev_printk(KERN_INFO, sdev,
1455 "%s: Sending START_UNIT\n",
1456 current->comm));
1457
1458 if (!scsi_eh_try_stu(stu_scmd)) {
1459 if (!scsi_device_online(sdev) ||
1460 !scsi_eh_tur(stu_scmd)) {
1461 list_for_each_entry_safe(scmd, next,
1462 work_q, eh_entry) {
1463 if (scmd->device == sdev &&
1464 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1465 scsi_eh_finish_cmd(scmd, done_q);
1466 }
1467 }
1468 } else {
1469 SCSI_LOG_ERROR_RECOVERY(3,
1470 sdev_printk(KERN_INFO, sdev,
1471 "%s: START_UNIT failed\n",
1472 current->comm));
1473 }
1474 }
1475
1476 return list_empty(work_q);
1477}
1478
1479
1480/**
1481 * scsi_eh_bus_device_reset - send bdr if needed
1482 * @shost: scsi host being recovered.
1483 * @work_q: &list_head for pending commands.
1484 * @done_q: &list_head for processed commands.
1485 *
1486 * Notes:
1487 * Try a bus device reset. Still, look to see whether we have multiple
1488 * devices that are jammed or not - if we have multiple devices, it
1489 * makes no sense to try bus_device_reset - we really would need to try
1490 * a bus_reset instead.
1491 */
1492static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1493 struct list_head *work_q,
1494 struct list_head *done_q)
1495{
1496 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1497 struct scsi_device *sdev;
1498 enum scsi_disposition rtn;
1499
1500 shost_for_each_device(sdev, shost) {
1501 if (scsi_host_eh_past_deadline(shost)) {
1502 SCSI_LOG_ERROR_RECOVERY(3,
1503 sdev_printk(KERN_INFO, sdev,
1504 "%s: skip BDR, past eh deadline\n",
1505 current->comm));
1506 scsi_device_put(sdev);
1507 break;
1508 }
1509 bdr_scmd = NULL;
1510 list_for_each_entry(scmd, work_q, eh_entry)
1511 if (scmd->device == sdev) {
1512 bdr_scmd = scmd;
1513 break;
1514 }
1515
1516 if (!bdr_scmd)
1517 continue;
1518
1519 SCSI_LOG_ERROR_RECOVERY(3,
1520 sdev_printk(KERN_INFO, sdev,
1521 "%s: Sending BDR\n", current->comm));
1522 rtn = scsi_try_bus_device_reset(bdr_scmd);
1523 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1524 if (!scsi_device_online(sdev) ||
1525 rtn == FAST_IO_FAIL ||
1526 !scsi_eh_tur(bdr_scmd)) {
1527 list_for_each_entry_safe(scmd, next,
1528 work_q, eh_entry) {
1529 if (scmd->device == sdev &&
1530 scsi_eh_action(scmd, rtn) != FAILED)
1531 scsi_eh_finish_cmd(scmd,
1532 done_q);
1533 }
1534 }
1535 } else {
1536 SCSI_LOG_ERROR_RECOVERY(3,
1537 sdev_printk(KERN_INFO, sdev,
1538 "%s: BDR failed\n", current->comm));
1539 }
1540 }
1541
1542 return list_empty(work_q);
1543}
1544
1545/**
1546 * scsi_eh_target_reset - send target reset if needed
1547 * @shost: scsi host being recovered.
1548 * @work_q: &list_head for pending commands.
1549 * @done_q: &list_head for processed commands.
1550 *
1551 * Notes:
1552 * Try a target reset.
1553 */
1554static int scsi_eh_target_reset(struct Scsi_Host *shost,
1555 struct list_head *work_q,
1556 struct list_head *done_q)
1557{
1558 LIST_HEAD(tmp_list);
1559 LIST_HEAD(check_list);
1560
1561 list_splice_init(work_q, &tmp_list);
1562
1563 while (!list_empty(&tmp_list)) {
1564 struct scsi_cmnd *next, *scmd;
1565 enum scsi_disposition rtn;
1566 unsigned int id;
1567
1568 if (scsi_host_eh_past_deadline(shost)) {
1569 /* push back on work queue for further processing */
1570 list_splice_init(&check_list, work_q);
1571 list_splice_init(&tmp_list, work_q);
1572 SCSI_LOG_ERROR_RECOVERY(3,
1573 shost_printk(KERN_INFO, shost,
1574 "%s: Skip target reset, past eh deadline\n",
1575 current->comm));
1576 return list_empty(work_q);
1577 }
1578
1579 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1580 id = scmd_id(scmd);
1581
1582 SCSI_LOG_ERROR_RECOVERY(3,
1583 shost_printk(KERN_INFO, shost,
1584 "%s: Sending target reset to target %d\n",
1585 current->comm, id));
1586 rtn = scsi_try_target_reset(scmd);
1587 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1588 SCSI_LOG_ERROR_RECOVERY(3,
1589 shost_printk(KERN_INFO, shost,
1590 "%s: Target reset failed"
1591 " target: %d\n",
1592 current->comm, id));
1593 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1594 if (scmd_id(scmd) != id)
1595 continue;
1596
1597 if (rtn == SUCCESS)
1598 list_move_tail(&scmd->eh_entry, &check_list);
1599 else if (rtn == FAST_IO_FAIL)
1600 scsi_eh_finish_cmd(scmd, done_q);
1601 else
1602 /* push back on work queue for further processing */
1603 list_move(&scmd->eh_entry, work_q);
1604 }
1605 }
1606
1607 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1608}
1609
1610/**
1611 * scsi_eh_bus_reset - send a bus reset
1612 * @shost: &scsi host being recovered.
1613 * @work_q: &list_head for pending commands.
1614 * @done_q: &list_head for processed commands.
1615 */
1616static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1617 struct list_head *work_q,
1618 struct list_head *done_q)
1619{
1620 struct scsi_cmnd *scmd, *chan_scmd, *next;
1621 LIST_HEAD(check_list);
1622 unsigned int channel;
1623 enum scsi_disposition rtn;
1624
1625 /*
1626 * we really want to loop over the various channels, and do this on
1627 * a channel by channel basis. we should also check to see if any
1628 * of the failed commands are on soft_reset devices, and if so, skip
1629 * the reset.
1630 */
1631
1632 for (channel = 0; channel <= shost->max_channel; channel++) {
1633 if (scsi_host_eh_past_deadline(shost)) {
1634 list_splice_init(&check_list, work_q);
1635 SCSI_LOG_ERROR_RECOVERY(3,
1636 shost_printk(KERN_INFO, shost,
1637 "%s: skip BRST, past eh deadline\n",
1638 current->comm));
1639 return list_empty(work_q);
1640 }
1641
1642 chan_scmd = NULL;
1643 list_for_each_entry(scmd, work_q, eh_entry) {
1644 if (channel == scmd_channel(scmd)) {
1645 chan_scmd = scmd;
1646 break;
1647 /*
1648 * FIXME add back in some support for
1649 * soft_reset devices.
1650 */
1651 }
1652 }
1653
1654 if (!chan_scmd)
1655 continue;
1656 SCSI_LOG_ERROR_RECOVERY(3,
1657 shost_printk(KERN_INFO, shost,
1658 "%s: Sending BRST chan: %d\n",
1659 current->comm, channel));
1660 rtn = scsi_try_bus_reset(chan_scmd);
1661 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1662 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1663 if (channel == scmd_channel(scmd)) {
1664 if (rtn == FAST_IO_FAIL)
1665 scsi_eh_finish_cmd(scmd,
1666 done_q);
1667 else
1668 list_move_tail(&scmd->eh_entry,
1669 &check_list);
1670 }
1671 }
1672 } else {
1673 SCSI_LOG_ERROR_RECOVERY(3,
1674 shost_printk(KERN_INFO, shost,
1675 "%s: BRST failed chan: %d\n",
1676 current->comm, channel));
1677 }
1678 }
1679 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1680}
1681
1682/**
1683 * scsi_eh_host_reset - send a host reset
1684 * @shost: host to be reset.
1685 * @work_q: &list_head for pending commands.
1686 * @done_q: &list_head for processed commands.
1687 */
1688static int scsi_eh_host_reset(struct Scsi_Host *shost,
1689 struct list_head *work_q,
1690 struct list_head *done_q)
1691{
1692 struct scsi_cmnd *scmd, *next;
1693 LIST_HEAD(check_list);
1694 enum scsi_disposition rtn;
1695
1696 if (!list_empty(work_q)) {
1697 scmd = list_entry(work_q->next,
1698 struct scsi_cmnd, eh_entry);
1699
1700 SCSI_LOG_ERROR_RECOVERY(3,
1701 shost_printk(KERN_INFO, shost,
1702 "%s: Sending HRST\n",
1703 current->comm));
1704
1705 rtn = scsi_try_host_reset(scmd);
1706 if (rtn == SUCCESS) {
1707 list_splice_init(work_q, &check_list);
1708 } else if (rtn == FAST_IO_FAIL) {
1709 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1710 scsi_eh_finish_cmd(scmd, done_q);
1711 }
1712 } else {
1713 SCSI_LOG_ERROR_RECOVERY(3,
1714 shost_printk(KERN_INFO, shost,
1715 "%s: HRST failed\n",
1716 current->comm));
1717 }
1718 }
1719 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1720}
1721
1722/**
1723 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1724 * @work_q: &list_head for pending commands.
1725 * @done_q: &list_head for processed commands.
1726 */
1727static void scsi_eh_offline_sdevs(struct list_head *work_q,
1728 struct list_head *done_q)
1729{
1730 struct scsi_cmnd *scmd, *next;
1731 struct scsi_device *sdev;
1732
1733 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1734 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1735 "not ready after error recovery\n");
1736 sdev = scmd->device;
1737
1738 mutex_lock(&sdev->state_mutex);
1739 scsi_device_set_state(sdev, SDEV_OFFLINE);
1740 mutex_unlock(&sdev->state_mutex);
1741
1742 scsi_eh_finish_cmd(scmd, done_q);
1743 }
1744 return;
1745}
1746
1747/**
1748 * scsi_noretry_cmd - determine if command should be failed fast
1749 * @scmd: SCSI cmd to examine.
1750 */
1751int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1752{
1753 switch (host_byte(scmd->result)) {
1754 case DID_OK:
1755 break;
1756 case DID_TIME_OUT:
1757 goto check_type;
1758 case DID_BUS_BUSY:
1759 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1760 case DID_PARITY:
1761 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1762 case DID_ERROR:
1763 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1764 return 0;
1765 fallthrough;
1766 case DID_SOFT_ERROR:
1767 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1768 }
1769
1770 if (!scsi_status_is_check_condition(scmd->result))
1771 return 0;
1772
1773check_type:
1774 /*
1775 * assume caller has checked sense and determined
1776 * the check condition was retryable.
1777 */
1778 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1779 blk_rq_is_passthrough(scmd->request))
1780 return 1;
1781
1782 return 0;
1783}
1784
1785/**
1786 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1787 * @scmd: SCSI cmd to examine.
1788 *
1789 * Notes:
1790 * This is *only* called when we are examining the status after sending
1791 * out the actual data command. any commands that are queued for error
1792 * recovery (e.g. test_unit_ready) do *not* come through here.
1793 *
1794 * When this routine returns failed, it means the error handler thread
1795 * is woken. In cases where the error code indicates an error that
1796 * doesn't require the error handler read (i.e. we don't need to
1797 * abort/reset), this function should return SUCCESS.
1798 */
1799enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1800{
1801 enum scsi_disposition rtn;
1802
1803 /*
1804 * if the device is offline, then we clearly just pass the result back
1805 * up to the top level.
1806 */
1807 if (!scsi_device_online(scmd->device)) {
1808 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1809 "%s: device offline - report as SUCCESS\n", __func__));
1810 return SUCCESS;
1811 }
1812
1813 /*
1814 * first check the host byte, to see if there is anything in there
1815 * that would indicate what we need to do.
1816 */
1817 switch (host_byte(scmd->result)) {
1818 case DID_PASSTHROUGH:
1819 /*
1820 * no matter what, pass this through to the upper layer.
1821 * nuke this special code so that it looks like we are saying
1822 * did_ok.
1823 */
1824 scmd->result &= 0xff00ffff;
1825 return SUCCESS;
1826 case DID_OK:
1827 /*
1828 * looks good. drop through, and check the next byte.
1829 */
1830 break;
1831 case DID_ABORT:
1832 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1833 set_host_byte(scmd, DID_TIME_OUT);
1834 return SUCCESS;
1835 }
1836 fallthrough;
1837 case DID_NO_CONNECT:
1838 case DID_BAD_TARGET:
1839 /*
1840 * note - this means that we just report the status back
1841 * to the top level driver, not that we actually think
1842 * that it indicates SUCCESS.
1843 */
1844 return SUCCESS;
1845 case DID_SOFT_ERROR:
1846 /*
1847 * when the low level driver returns did_soft_error,
1848 * it is responsible for keeping an internal retry counter
1849 * in order to avoid endless loops (db)
1850 */
1851 goto maybe_retry;
1852 case DID_IMM_RETRY:
1853 return NEEDS_RETRY;
1854
1855 case DID_REQUEUE:
1856 return ADD_TO_MLQUEUE;
1857 case DID_TRANSPORT_DISRUPTED:
1858 /*
1859 * LLD/transport was disrupted during processing of the IO.
1860 * The transport class is now blocked/blocking,
1861 * and the transport will decide what to do with the IO
1862 * based on its timers and recovery capablilities if
1863 * there are enough retries.
1864 */
1865 goto maybe_retry;
1866 case DID_TRANSPORT_FAILFAST:
1867 /*
1868 * The transport decided to failfast the IO (most likely
1869 * the fast io fail tmo fired), so send IO directly upwards.
1870 */
1871 return SUCCESS;
1872 case DID_TRANSPORT_MARGINAL:
1873 /*
1874 * caller has decided not to do retries on
1875 * abort success, so send IO directly upwards
1876 */
1877 return SUCCESS;
1878 case DID_ERROR:
1879 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1880 /*
1881 * execute reservation conflict processing code
1882 * lower down
1883 */
1884 break;
1885 fallthrough;
1886 case DID_BUS_BUSY:
1887 case DID_PARITY:
1888 goto maybe_retry;
1889 case DID_TIME_OUT:
1890 /*
1891 * when we scan the bus, we get timeout messages for
1892 * these commands if there is no device available.
1893 * other hosts report did_no_connect for the same thing.
1894 */
1895 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1896 scmd->cmnd[0] == INQUIRY)) {
1897 return SUCCESS;
1898 } else {
1899 return FAILED;
1900 }
1901 case DID_RESET:
1902 return SUCCESS;
1903 default:
1904 return FAILED;
1905 }
1906
1907 /*
1908 * check the status byte to see if this indicates anything special.
1909 */
1910 switch (get_status_byte(scmd)) {
1911 case SAM_STAT_TASK_SET_FULL:
1912 scsi_handle_queue_full(scmd->device);
1913 /*
1914 * the case of trying to send too many commands to a
1915 * tagged queueing device.
1916 */
1917 fallthrough;
1918 case SAM_STAT_BUSY:
1919 /*
1920 * device can't talk to us at the moment. Should only
1921 * occur (SAM-3) when the task queue is empty, so will cause
1922 * the empty queue handling to trigger a stall in the
1923 * device.
1924 */
1925 return ADD_TO_MLQUEUE;
1926 case SAM_STAT_GOOD:
1927 if (scmd->cmnd[0] == REPORT_LUNS)
1928 scmd->device->sdev_target->expecting_lun_change = 0;
1929 scsi_handle_queue_ramp_up(scmd->device);
1930 fallthrough;
1931 case SAM_STAT_COMMAND_TERMINATED:
1932 return SUCCESS;
1933 case SAM_STAT_TASK_ABORTED:
1934 goto maybe_retry;
1935 case SAM_STAT_CHECK_CONDITION:
1936 rtn = scsi_check_sense(scmd);
1937 if (rtn == NEEDS_RETRY)
1938 goto maybe_retry;
1939 /* if rtn == FAILED, we have no sense information;
1940 * returning FAILED will wake the error handler thread
1941 * to collect the sense and redo the decide
1942 * disposition */
1943 return rtn;
1944 case SAM_STAT_CONDITION_MET:
1945 case SAM_STAT_INTERMEDIATE:
1946 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
1947 case SAM_STAT_ACA_ACTIVE:
1948 /*
1949 * who knows? FIXME(eric)
1950 */
1951 return SUCCESS;
1952
1953 case SAM_STAT_RESERVATION_CONFLICT:
1954 sdev_printk(KERN_INFO, scmd->device,
1955 "reservation conflict\n");
1956 set_host_byte(scmd, DID_NEXUS_FAILURE);
1957 return SUCCESS; /* causes immediate i/o error */
1958 default:
1959 return FAILED;
1960 }
1961 return FAILED;
1962
1963maybe_retry:
1964
1965 /* we requeue for retry because the error was retryable, and
1966 * the request was not marked fast fail. Note that above,
1967 * even if the request is marked fast fail, we still requeue
1968 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1969 if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
1970 return NEEDS_RETRY;
1971 } else {
1972 /*
1973 * no more retries - report this one back to upper level.
1974 */
1975 return SUCCESS;
1976 }
1977}
1978
1979static void eh_lock_door_done(struct request *req, blk_status_t status)
1980{
1981 blk_put_request(req);
1982}
1983
1984/**
1985 * scsi_eh_lock_door - Prevent medium removal for the specified device
1986 * @sdev: SCSI device to prevent medium removal
1987 *
1988 * Locking:
1989 * We must be called from process context.
1990 *
1991 * Notes:
1992 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1993 * head of the devices request queue, and continue.
1994 */
1995static void scsi_eh_lock_door(struct scsi_device *sdev)
1996{
1997 struct request *req;
1998 struct scsi_request *rq;
1999
2000 req = blk_get_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
2001 if (IS_ERR(req))
2002 return;
2003 rq = scsi_req(req);
2004
2005 rq->cmd[0] = ALLOW_MEDIUM_REMOVAL;
2006 rq->cmd[1] = 0;
2007 rq->cmd[2] = 0;
2008 rq->cmd[3] = 0;
2009 rq->cmd[4] = SCSI_REMOVAL_PREVENT;
2010 rq->cmd[5] = 0;
2011 rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
2012
2013 req->rq_flags |= RQF_QUIET;
2014 req->timeout = 10 * HZ;
2015 rq->retries = 5;
2016
2017 blk_execute_rq_nowait(NULL, req, 1, eh_lock_door_done);
2018}
2019
2020/**
2021 * scsi_restart_operations - restart io operations to the specified host.
2022 * @shost: Host we are restarting.
2023 *
2024 * Notes:
2025 * When we entered the error handler, we blocked all further i/o to
2026 * this device. we need to 'reverse' this process.
2027 */
2028static void scsi_restart_operations(struct Scsi_Host *shost)
2029{
2030 struct scsi_device *sdev;
2031 unsigned long flags;
2032
2033 /*
2034 * If the door was locked, we need to insert a door lock request
2035 * onto the head of the SCSI request queue for the device. There
2036 * is no point trying to lock the door of an off-line device.
2037 */
2038 shost_for_each_device(sdev, shost) {
2039 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2040 scsi_eh_lock_door(sdev);
2041 sdev->was_reset = 0;
2042 }
2043 }
2044
2045 /*
2046 * next free up anything directly waiting upon the host. this
2047 * will be requests for character device operations, and also for
2048 * ioctls to queued block devices.
2049 */
2050 SCSI_LOG_ERROR_RECOVERY(3,
2051 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2052
2053 spin_lock_irqsave(shost->host_lock, flags);
2054 if (scsi_host_set_state(shost, SHOST_RUNNING))
2055 if (scsi_host_set_state(shost, SHOST_CANCEL))
2056 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2057 spin_unlock_irqrestore(shost->host_lock, flags);
2058
2059 wake_up(&shost->host_wait);
2060
2061 /*
2062 * finally we need to re-initiate requests that may be pending. we will
2063 * have had everything blocked while error handling is taking place, and
2064 * now that error recovery is done, we will need to ensure that these
2065 * requests are started.
2066 */
2067 scsi_run_host_queues(shost);
2068
2069 /*
2070 * if eh is active and host_eh_scheduled is pending we need to re-run
2071 * recovery. we do this check after scsi_run_host_queues() to allow
2072 * everything pent up since the last eh run a chance to make forward
2073 * progress before we sync again. Either we'll immediately re-run
2074 * recovery or scsi_device_unbusy() will wake us again when these
2075 * pending commands complete.
2076 */
2077 spin_lock_irqsave(shost->host_lock, flags);
2078 if (shost->host_eh_scheduled)
2079 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2080 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2081 spin_unlock_irqrestore(shost->host_lock, flags);
2082}
2083
2084/**
2085 * scsi_eh_ready_devs - check device ready state and recover if not.
2086 * @shost: host to be recovered.
2087 * @work_q: &list_head for pending commands.
2088 * @done_q: &list_head for processed commands.
2089 */
2090void scsi_eh_ready_devs(struct Scsi_Host *shost,
2091 struct list_head *work_q,
2092 struct list_head *done_q)
2093{
2094 if (!scsi_eh_stu(shost, work_q, done_q))
2095 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2096 if (!scsi_eh_target_reset(shost, work_q, done_q))
2097 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2098 if (!scsi_eh_host_reset(shost, work_q, done_q))
2099 scsi_eh_offline_sdevs(work_q,
2100 done_q);
2101}
2102EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2103
2104/**
2105 * scsi_eh_flush_done_q - finish processed commands or retry them.
2106 * @done_q: list_head of processed commands.
2107 */
2108void scsi_eh_flush_done_q(struct list_head *done_q)
2109{
2110 struct scsi_cmnd *scmd, *next;
2111
2112 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2113 list_del_init(&scmd->eh_entry);
2114 if (scsi_device_online(scmd->device) &&
2115 !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2116 scsi_eh_should_retry_cmd(scmd)) {
2117 SCSI_LOG_ERROR_RECOVERY(3,
2118 scmd_printk(KERN_INFO, scmd,
2119 "%s: flush retry cmd\n",
2120 current->comm));
2121 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2122 } else {
2123 /*
2124 * If just we got sense for the device (called
2125 * scsi_eh_get_sense), scmd->result is already
2126 * set, do not set DID_TIME_OUT.
2127 */
2128 if (!scmd->result)
2129 scmd->result |= (DID_TIME_OUT << 16);
2130 SCSI_LOG_ERROR_RECOVERY(3,
2131 scmd_printk(KERN_INFO, scmd,
2132 "%s: flush finish cmd\n",
2133 current->comm));
2134 scsi_finish_command(scmd);
2135 }
2136 }
2137}
2138EXPORT_SYMBOL(scsi_eh_flush_done_q);
2139
2140/**
2141 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2142 * @shost: Host to unjam.
2143 *
2144 * Notes:
2145 * When we come in here, we *know* that all commands on the bus have
2146 * either completed, failed or timed out. we also know that no further
2147 * commands are being sent to the host, so things are relatively quiet
2148 * and we have freedom to fiddle with things as we wish.
2149 *
2150 * This is only the *default* implementation. it is possible for
2151 * individual drivers to supply their own version of this function, and
2152 * if the maintainer wishes to do this, it is strongly suggested that
2153 * this function be taken as a template and modified. this function
2154 * was designed to correctly handle problems for about 95% of the
2155 * different cases out there, and it should always provide at least a
2156 * reasonable amount of error recovery.
2157 *
2158 * Any command marked 'failed' or 'timeout' must eventually have
2159 * scsi_finish_cmd() called for it. we do all of the retry stuff
2160 * here, so when we restart the host after we return it should have an
2161 * empty queue.
2162 */
2163static void scsi_unjam_host(struct Scsi_Host *shost)
2164{
2165 unsigned long flags;
2166 LIST_HEAD(eh_work_q);
2167 LIST_HEAD(eh_done_q);
2168
2169 spin_lock_irqsave(shost->host_lock, flags);
2170 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2171 spin_unlock_irqrestore(shost->host_lock, flags);
2172
2173 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2174
2175 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2176 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2177
2178 spin_lock_irqsave(shost->host_lock, flags);
2179 if (shost->eh_deadline != -1)
2180 shost->last_reset = 0;
2181 spin_unlock_irqrestore(shost->host_lock, flags);
2182 scsi_eh_flush_done_q(&eh_done_q);
2183}
2184
2185/**
2186 * scsi_error_handler - SCSI error handler thread
2187 * @data: Host for which we are running.
2188 *
2189 * Notes:
2190 * This is the main error handling loop. This is run as a kernel thread
2191 * for every SCSI host and handles all error handling activity.
2192 */
2193int scsi_error_handler(void *data)
2194{
2195 struct Scsi_Host *shost = data;
2196
2197 /*
2198 * We use TASK_INTERRUPTIBLE so that the thread is not
2199 * counted against the load average as a running process.
2200 * We never actually get interrupted because kthread_run
2201 * disables signal delivery for the created thread.
2202 */
2203 while (true) {
2204 /*
2205 * The sequence in kthread_stop() sets the stop flag first
2206 * then wakes the process. To avoid missed wakeups, the task
2207 * should always be in a non running state before the stop
2208 * flag is checked
2209 */
2210 set_current_state(TASK_INTERRUPTIBLE);
2211 if (kthread_should_stop())
2212 break;
2213
2214 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2215 shost->host_failed != scsi_host_busy(shost)) {
2216 SCSI_LOG_ERROR_RECOVERY(1,
2217 shost_printk(KERN_INFO, shost,
2218 "scsi_eh_%d: sleeping\n",
2219 shost->host_no));
2220 schedule();
2221 continue;
2222 }
2223
2224 __set_current_state(TASK_RUNNING);
2225 SCSI_LOG_ERROR_RECOVERY(1,
2226 shost_printk(KERN_INFO, shost,
2227 "scsi_eh_%d: waking up %d/%d/%d\n",
2228 shost->host_no, shost->host_eh_scheduled,
2229 shost->host_failed,
2230 scsi_host_busy(shost)));
2231
2232 /*
2233 * We have a host that is failing for some reason. Figure out
2234 * what we need to do to get it up and online again (if we can).
2235 * If we fail, we end up taking the thing offline.
2236 */
2237 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2238 SCSI_LOG_ERROR_RECOVERY(1,
2239 shost_printk(KERN_ERR, shost,
2240 "scsi_eh_%d: unable to autoresume\n",
2241 shost->host_no));
2242 continue;
2243 }
2244
2245 if (shost->transportt->eh_strategy_handler)
2246 shost->transportt->eh_strategy_handler(shost);
2247 else
2248 scsi_unjam_host(shost);
2249
2250 /* All scmds have been handled */
2251 shost->host_failed = 0;
2252
2253 /*
2254 * Note - if the above fails completely, the action is to take
2255 * individual devices offline and flush the queue of any
2256 * outstanding requests that may have been pending. When we
2257 * restart, we restart any I/O to any other devices on the bus
2258 * which are still online.
2259 */
2260 scsi_restart_operations(shost);
2261 if (!shost->eh_noresume)
2262 scsi_autopm_put_host(shost);
2263 }
2264 __set_current_state(TASK_RUNNING);
2265
2266 SCSI_LOG_ERROR_RECOVERY(1,
2267 shost_printk(KERN_INFO, shost,
2268 "Error handler scsi_eh_%d exiting\n",
2269 shost->host_no));
2270 shost->ehandler = NULL;
2271 return 0;
2272}
2273
2274/*
2275 * Function: scsi_report_bus_reset()
2276 *
2277 * Purpose: Utility function used by low-level drivers to report that
2278 * they have observed a bus reset on the bus being handled.
2279 *
2280 * Arguments: shost - Host in question
2281 * channel - channel on which reset was observed.
2282 *
2283 * Returns: Nothing
2284 *
2285 * Lock status: Host lock must be held.
2286 *
2287 * Notes: This only needs to be called if the reset is one which
2288 * originates from an unknown location. Resets originated
2289 * by the mid-level itself don't need to call this, but there
2290 * should be no harm.
2291 *
2292 * The main purpose of this is to make sure that a CHECK_CONDITION
2293 * is properly treated.
2294 */
2295void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2296{
2297 struct scsi_device *sdev;
2298
2299 __shost_for_each_device(sdev, shost) {
2300 if (channel == sdev_channel(sdev))
2301 __scsi_report_device_reset(sdev, NULL);
2302 }
2303}
2304EXPORT_SYMBOL(scsi_report_bus_reset);
2305
2306/*
2307 * Function: scsi_report_device_reset()
2308 *
2309 * Purpose: Utility function used by low-level drivers to report that
2310 * they have observed a device reset on the device being handled.
2311 *
2312 * Arguments: shost - Host in question
2313 * channel - channel on which reset was observed
2314 * target - target on which reset was observed
2315 *
2316 * Returns: Nothing
2317 *
2318 * Lock status: Host lock must be held
2319 *
2320 * Notes: This only needs to be called if the reset is one which
2321 * originates from an unknown location. Resets originated
2322 * by the mid-level itself don't need to call this, but there
2323 * should be no harm.
2324 *
2325 * The main purpose of this is to make sure that a CHECK_CONDITION
2326 * is properly treated.
2327 */
2328void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2329{
2330 struct scsi_device *sdev;
2331
2332 __shost_for_each_device(sdev, shost) {
2333 if (channel == sdev_channel(sdev) &&
2334 target == sdev_id(sdev))
2335 __scsi_report_device_reset(sdev, NULL);
2336 }
2337}
2338EXPORT_SYMBOL(scsi_report_device_reset);
2339
2340static void
2341scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2342{
2343}
2344
2345/**
2346 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2347 * @dev: scsi_device to operate on
2348 * @arg: reset type (see sg.h)
2349 */
2350int
2351scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2352{
2353 struct scsi_cmnd *scmd;
2354 struct Scsi_Host *shost = dev->host;
2355 struct request *rq;
2356 unsigned long flags;
2357 int error = 0, val;
2358 enum scsi_disposition rtn;
2359
2360 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2361 return -EACCES;
2362
2363 error = get_user(val, arg);
2364 if (error)
2365 return error;
2366
2367 if (scsi_autopm_get_host(shost) < 0)
2368 return -EIO;
2369
2370 error = -EIO;
2371 rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2372 shost->hostt->cmd_size, GFP_KERNEL);
2373 if (!rq)
2374 goto out_put_autopm_host;
2375 blk_rq_init(NULL, rq);
2376
2377 scmd = (struct scsi_cmnd *)(rq + 1);
2378 scsi_init_command(dev, scmd);
2379 scmd->request = rq;
2380 scmd->cmnd = scsi_req(rq)->cmd;
2381
2382 scmd->scsi_done = scsi_reset_provider_done_command;
2383 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2384
2385 scmd->cmd_len = 0;
2386
2387 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2388
2389 spin_lock_irqsave(shost->host_lock, flags);
2390 shost->tmf_in_progress = 1;
2391 spin_unlock_irqrestore(shost->host_lock, flags);
2392
2393 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2394 case SG_SCSI_RESET_NOTHING:
2395 rtn = SUCCESS;
2396 break;
2397 case SG_SCSI_RESET_DEVICE:
2398 rtn = scsi_try_bus_device_reset(scmd);
2399 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2400 break;
2401 fallthrough;
2402 case SG_SCSI_RESET_TARGET:
2403 rtn = scsi_try_target_reset(scmd);
2404 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2405 break;
2406 fallthrough;
2407 case SG_SCSI_RESET_BUS:
2408 rtn = scsi_try_bus_reset(scmd);
2409 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2410 break;
2411 fallthrough;
2412 case SG_SCSI_RESET_HOST:
2413 rtn = scsi_try_host_reset(scmd);
2414 if (rtn == SUCCESS)
2415 break;
2416 fallthrough;
2417 default:
2418 rtn = FAILED;
2419 break;
2420 }
2421
2422 error = (rtn == SUCCESS) ? 0 : -EIO;
2423
2424 spin_lock_irqsave(shost->host_lock, flags);
2425 shost->tmf_in_progress = 0;
2426 spin_unlock_irqrestore(shost->host_lock, flags);
2427
2428 /*
2429 * be sure to wake up anyone who was sleeping or had their queue
2430 * suspended while we performed the TMF.
2431 */
2432 SCSI_LOG_ERROR_RECOVERY(3,
2433 shost_printk(KERN_INFO, shost,
2434 "waking up host to restart after TMF\n"));
2435
2436 wake_up(&shost->host_wait);
2437 scsi_run_host_queues(shost);
2438
2439 kfree(rq);
2440
2441out_put_autopm_host:
2442 scsi_autopm_put_host(shost);
2443 return error;
2444}
2445
2446bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2447 struct scsi_sense_hdr *sshdr)
2448{
2449 return scsi_normalize_sense(cmd->sense_buffer,
2450 SCSI_SENSE_BUFFERSIZE, sshdr);
2451}
2452EXPORT_SYMBOL(scsi_command_normalize_sense);
2453
2454/**
2455 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2456 * @sense_buffer: byte array of sense data
2457 * @sb_len: number of valid bytes in sense_buffer
2458 * @info_out: pointer to 64 integer where 8 or 4 byte information
2459 * field will be placed if found.
2460 *
2461 * Return value:
2462 * true if information field found, false if not found.
2463 */
2464bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2465 u64 *info_out)
2466{
2467 const u8 * ucp;
2468
2469 if (sb_len < 7)
2470 return false;
2471 switch (sense_buffer[0] & 0x7f) {
2472 case 0x70:
2473 case 0x71:
2474 if (sense_buffer[0] & 0x80) {
2475 *info_out = get_unaligned_be32(&sense_buffer[3]);
2476 return true;
2477 }
2478 return false;
2479 case 0x72:
2480 case 0x73:
2481 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2482 0 /* info desc */);
2483 if (ucp && (0xa == ucp[1])) {
2484 *info_out = get_unaligned_be64(&ucp[4]);
2485 return true;
2486 }
2487 return false;
2488 default:
2489 return false;
2490 }
2491}
2492EXPORT_SYMBOL(scsi_get_sense_info_fld);
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_transport.h>
37#include <scsi/scsi_host.h>
38#include <scsi/scsi_ioctl.h>
39
40#include "scsi_priv.h"
41#include "scsi_logging.h"
42#include "scsi_transport_api.h"
43
44#include <trace/events/scsi.h>
45
46static void scsi_eh_done(struct scsi_cmnd *scmd);
47
48/*
49 * These should *probably* be handled by the host itself.
50 * Since it is allowed to sleep, it probably should.
51 */
52#define BUS_RESET_SETTLE_TIME (10)
53#define HOST_RESET_SETTLE_TIME (10)
54
55static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
56static int scsi_try_to_abort_cmd(struct scsi_host_template *,
57 struct scsi_cmnd *);
58
59/* called with shost->host_lock held */
60void scsi_eh_wakeup(struct Scsi_Host *shost)
61{
62 if (shost->host_busy == shost->host_failed) {
63 trace_scsi_eh_wakeup(shost);
64 wake_up_process(shost->ehandler);
65 SCSI_LOG_ERROR_RECOVERY(5,
66 printk("Waking error handler thread\n"));
67 }
68}
69
70/**
71 * scsi_schedule_eh - schedule EH for SCSI host
72 * @shost: SCSI host to invoke error handling on.
73 *
74 * Schedule SCSI EH without scmd.
75 */
76void scsi_schedule_eh(struct Scsi_Host *shost)
77{
78 unsigned long flags;
79
80 spin_lock_irqsave(shost->host_lock, flags);
81
82 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
83 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
84 shost->host_eh_scheduled++;
85 scsi_eh_wakeup(shost);
86 }
87
88 spin_unlock_irqrestore(shost->host_lock, flags);
89}
90EXPORT_SYMBOL_GPL(scsi_schedule_eh);
91
92static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
93{
94 if (!shost->last_reset || shost->eh_deadline == -1)
95 return 0;
96
97 /*
98 * 32bit accesses are guaranteed to be atomic
99 * (on all supported architectures), so instead
100 * of using a spinlock we can as well double check
101 * if eh_deadline has been set to 'off' during the
102 * time_before call.
103 */
104 if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
105 shost->eh_deadline > -1)
106 return 0;
107
108 return 1;
109}
110
111/**
112 * scmd_eh_abort_handler - Handle command aborts
113 * @work: command to be aborted.
114 */
115void
116scmd_eh_abort_handler(struct work_struct *work)
117{
118 struct scsi_cmnd *scmd =
119 container_of(work, struct scsi_cmnd, abort_work.work);
120 struct scsi_device *sdev = scmd->device;
121 int rtn;
122
123 if (scsi_host_eh_past_deadline(sdev->host)) {
124 SCSI_LOG_ERROR_RECOVERY(3,
125 scmd_printk(KERN_INFO, scmd,
126 "scmd %p eh timeout, not aborting\n",
127 scmd));
128 } else {
129 SCSI_LOG_ERROR_RECOVERY(3,
130 scmd_printk(KERN_INFO, scmd,
131 "aborting command %p\n", scmd));
132 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
133 if (rtn == SUCCESS) {
134 scmd->result |= DID_TIME_OUT << 16;
135 if (scsi_host_eh_past_deadline(sdev->host)) {
136 SCSI_LOG_ERROR_RECOVERY(3,
137 scmd_printk(KERN_INFO, scmd,
138 "scmd %p eh timeout, "
139 "not retrying aborted "
140 "command\n", scmd));
141 } else if (!scsi_noretry_cmd(scmd) &&
142 (++scmd->retries <= scmd->allowed)) {
143 SCSI_LOG_ERROR_RECOVERY(3,
144 scmd_printk(KERN_WARNING, scmd,
145 "scmd %p retry "
146 "aborted command\n", scmd));
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 "scmd %p finish "
153 "aborted command\n", scmd));
154 scsi_finish_command(scmd);
155 return;
156 }
157 } else {
158 SCSI_LOG_ERROR_RECOVERY(3,
159 scmd_printk(KERN_INFO, scmd,
160 "scmd %p abort failed, rtn %d\n",
161 scmd, rtn));
162 }
163 }
164
165 if (!scsi_eh_scmd_add(scmd, 0)) {
166 SCSI_LOG_ERROR_RECOVERY(3,
167 scmd_printk(KERN_WARNING, scmd,
168 "scmd %p terminate "
169 "aborted command\n", scmd));
170 scmd->result |= DID_TIME_OUT << 16;
171 scsi_finish_command(scmd);
172 }
173}
174
175/**
176 * scsi_abort_command - schedule a command abort
177 * @scmd: scmd to abort.
178 *
179 * We only need to abort commands after a command timeout
180 */
181static int
182scsi_abort_command(struct scsi_cmnd *scmd)
183{
184 struct scsi_device *sdev = scmd->device;
185 struct Scsi_Host *shost = sdev->host;
186 unsigned long flags;
187
188 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
189 /*
190 * Retry after abort failed, escalate to next level.
191 */
192 scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
193 SCSI_LOG_ERROR_RECOVERY(3,
194 scmd_printk(KERN_INFO, scmd,
195 "scmd %p previous abort failed\n", scmd));
196 cancel_delayed_work(&scmd->abort_work);
197 return FAILED;
198 }
199
200 /*
201 * Do not try a command abort if
202 * SCSI EH has already started.
203 */
204 spin_lock_irqsave(shost->host_lock, flags);
205 if (scsi_host_in_recovery(shost)) {
206 spin_unlock_irqrestore(shost->host_lock, flags);
207 SCSI_LOG_ERROR_RECOVERY(3,
208 scmd_printk(KERN_INFO, scmd,
209 "scmd %p not aborting, host in recovery\n",
210 scmd));
211 return FAILED;
212 }
213
214 if (shost->eh_deadline != -1 && !shost->last_reset)
215 shost->last_reset = jiffies;
216 spin_unlock_irqrestore(shost->host_lock, flags);
217
218 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
219 SCSI_LOG_ERROR_RECOVERY(3,
220 scmd_printk(KERN_INFO, scmd,
221 "scmd %p abort scheduled\n", scmd));
222 queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
223 return SUCCESS;
224}
225
226/**
227 * scsi_eh_scmd_add - add scsi cmd to error handling.
228 * @scmd: scmd to run eh on.
229 * @eh_flag: optional SCSI_EH flag.
230 *
231 * Return value:
232 * 0 on failure.
233 */
234int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
235{
236 struct Scsi_Host *shost = scmd->device->host;
237 unsigned long flags;
238 int ret = 0;
239
240 if (!shost->ehandler)
241 return 0;
242
243 spin_lock_irqsave(shost->host_lock, flags);
244 if (scsi_host_set_state(shost, SHOST_RECOVERY))
245 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
246 goto out_unlock;
247
248 if (shost->eh_deadline != -1 && !shost->last_reset)
249 shost->last_reset = jiffies;
250
251 ret = 1;
252 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
253 eh_flag &= ~SCSI_EH_CANCEL_CMD;
254 scmd->eh_eflags |= eh_flag;
255 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
256 shost->host_failed++;
257 scsi_eh_wakeup(shost);
258 out_unlock:
259 spin_unlock_irqrestore(shost->host_lock, flags);
260 return ret;
261}
262
263/**
264 * scsi_times_out - Timeout function for normal scsi commands.
265 * @req: request that is timing out.
266 *
267 * Notes:
268 * We do not need to lock this. There is the potential for a race
269 * only in that the normal completion handling might run, but if the
270 * normal completion function determines that the timer has already
271 * fired, then it mustn't do anything.
272 */
273enum blk_eh_timer_return scsi_times_out(struct request *req)
274{
275 struct scsi_cmnd *scmd = req->special;
276 enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
277 struct Scsi_Host *host = scmd->device->host;
278
279 trace_scsi_dispatch_cmd_timeout(scmd);
280 scsi_log_completion(scmd, TIMEOUT_ERROR);
281
282 if (host->eh_deadline != -1 && !host->last_reset)
283 host->last_reset = jiffies;
284
285 if (host->transportt->eh_timed_out)
286 rtn = host->transportt->eh_timed_out(scmd);
287 else if (host->hostt->eh_timed_out)
288 rtn = host->hostt->eh_timed_out(scmd);
289
290 if (rtn == BLK_EH_NOT_HANDLED && !host->hostt->no_async_abort)
291 if (scsi_abort_command(scmd) == SUCCESS)
292 return BLK_EH_NOT_HANDLED;
293
294 scmd->result |= DID_TIME_OUT << 16;
295
296 if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
297 !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)))
298 rtn = BLK_EH_HANDLED;
299
300 return rtn;
301}
302
303/**
304 * scsi_block_when_processing_errors - Prevent cmds from being queued.
305 * @sdev: Device on which we are performing recovery.
306 *
307 * Description:
308 * We block until the host is out of error recovery, and then check to
309 * see whether the host or the device is offline.
310 *
311 * Return value:
312 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
313 */
314int scsi_block_when_processing_errors(struct scsi_device *sdev)
315{
316 int online;
317
318 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
319
320 online = scsi_device_online(sdev);
321
322 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
323 online));
324
325 return online;
326}
327EXPORT_SYMBOL(scsi_block_when_processing_errors);
328
329#ifdef CONFIG_SCSI_LOGGING
330/**
331 * scsi_eh_prt_fail_stats - Log info on failures.
332 * @shost: scsi host being recovered.
333 * @work_q: Queue of scsi cmds to process.
334 */
335static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
336 struct list_head *work_q)
337{
338 struct scsi_cmnd *scmd;
339 struct scsi_device *sdev;
340 int total_failures = 0;
341 int cmd_failed = 0;
342 int cmd_cancel = 0;
343 int devices_failed = 0;
344
345 shost_for_each_device(sdev, shost) {
346 list_for_each_entry(scmd, work_q, eh_entry) {
347 if (scmd->device == sdev) {
348 ++total_failures;
349 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
350 ++cmd_cancel;
351 else
352 ++cmd_failed;
353 }
354 }
355
356 if (cmd_cancel || cmd_failed) {
357 SCSI_LOG_ERROR_RECOVERY(3,
358 sdev_printk(KERN_INFO, sdev,
359 "%s: cmds failed: %d, cancel: %d\n",
360 __func__, cmd_failed,
361 cmd_cancel));
362 cmd_cancel = 0;
363 cmd_failed = 0;
364 ++devices_failed;
365 }
366 }
367
368 SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
369 " devices require eh work\n",
370 total_failures, devices_failed));
371}
372#endif
373
374 /**
375 * scsi_report_lun_change - Set flag on all *other* devices on the same target
376 * to indicate that a UNIT ATTENTION is expected.
377 * @sdev: Device reporting the UNIT ATTENTION
378 */
379static void scsi_report_lun_change(struct scsi_device *sdev)
380{
381 sdev->sdev_target->expecting_lun_change = 1;
382}
383
384/**
385 * scsi_report_sense - Examine scsi sense information and log messages for
386 * certain conditions, also issue uevents for some of them.
387 * @sdev: Device reporting the sense code
388 * @sshdr: sshdr to be examined
389 */
390static void scsi_report_sense(struct scsi_device *sdev,
391 struct scsi_sense_hdr *sshdr)
392{
393 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
394
395 if (sshdr->sense_key == UNIT_ATTENTION) {
396 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
397 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
398 sdev_printk(KERN_WARNING, sdev,
399 "Inquiry data has changed");
400 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
401 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
402 scsi_report_lun_change(sdev);
403 sdev_printk(KERN_WARNING, sdev,
404 "Warning! Received an indication that the "
405 "LUN assignments on this target have "
406 "changed. The Linux SCSI layer does not "
407 "automatically remap LUN assignments.\n");
408 } else if (sshdr->asc == 0x3f)
409 sdev_printk(KERN_WARNING, sdev,
410 "Warning! Received an indication that the "
411 "operating parameters on this target have "
412 "changed. The Linux SCSI layer does not "
413 "automatically adjust these parameters.\n");
414
415 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
416 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
417 sdev_printk(KERN_WARNING, sdev,
418 "Warning! Received an indication that the "
419 "LUN reached a thin provisioning soft "
420 "threshold.\n");
421 }
422
423 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
424 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
425 sdev_printk(KERN_WARNING, sdev,
426 "Mode parameters changed");
427 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
428 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
429 sdev_printk(KERN_WARNING, sdev,
430 "Capacity data has changed");
431 } else if (sshdr->asc == 0x2a)
432 sdev_printk(KERN_WARNING, sdev,
433 "Parameters changed");
434 }
435
436 if (evt_type != SDEV_EVT_MAXBITS) {
437 set_bit(evt_type, sdev->pending_events);
438 schedule_work(&sdev->event_work);
439 }
440}
441
442/**
443 * scsi_check_sense - Examine scsi cmd sense
444 * @scmd: Cmd to have sense checked.
445 *
446 * Return value:
447 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
448 *
449 * Notes:
450 * When a deferred error is detected the current command has
451 * not been executed and needs retrying.
452 */
453static int scsi_check_sense(struct scsi_cmnd *scmd)
454{
455 struct scsi_device *sdev = scmd->device;
456 struct scsi_sense_hdr sshdr;
457
458 if (! scsi_command_normalize_sense(scmd, &sshdr))
459 return FAILED; /* no valid sense data */
460
461 if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
462 /*
463 * nasty: for mid-layer issued TURs, we need to return the
464 * actual sense data without any recovery attempt. For eh
465 * issued ones, we need to try to recover and interpret
466 */
467 return SUCCESS;
468
469 scsi_report_sense(sdev, &sshdr);
470
471 if (scsi_sense_is_deferred(&sshdr))
472 return NEEDS_RETRY;
473
474 if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
475 sdev->scsi_dh_data->scsi_dh->check_sense) {
476 int rc;
477
478 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
479 if (rc != SCSI_RETURN_NOT_HANDLED)
480 return rc;
481 /* handler does not care. Drop down to default handling */
482 }
483
484 /*
485 * Previous logic looked for FILEMARK, EOM or ILI which are
486 * mainly associated with tapes and returned SUCCESS.
487 */
488 if (sshdr.response_code == 0x70) {
489 /* fixed format */
490 if (scmd->sense_buffer[2] & 0xe0)
491 return SUCCESS;
492 } else {
493 /*
494 * descriptor format: look for "stream commands sense data
495 * descriptor" (see SSC-3). Assume single sense data
496 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
497 */
498 if ((sshdr.additional_length > 3) &&
499 (scmd->sense_buffer[8] == 0x4) &&
500 (scmd->sense_buffer[11] & 0xe0))
501 return SUCCESS;
502 }
503
504 switch (sshdr.sense_key) {
505 case NO_SENSE:
506 return SUCCESS;
507 case RECOVERED_ERROR:
508 return /* soft_error */ SUCCESS;
509
510 case ABORTED_COMMAND:
511 if (sshdr.asc == 0x10) /* DIF */
512 return SUCCESS;
513
514 return NEEDS_RETRY;
515 case NOT_READY:
516 case UNIT_ATTENTION:
517 /*
518 * if we are expecting a cc/ua because of a bus reset that we
519 * performed, treat this just as a retry. otherwise this is
520 * information that we should pass up to the upper-level driver
521 * so that we can deal with it there.
522 */
523 if (scmd->device->expecting_cc_ua) {
524 /*
525 * Because some device does not queue unit
526 * attentions correctly, we carefully check
527 * additional sense code and qualifier so as
528 * not to squash media change unit attention.
529 */
530 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
531 scmd->device->expecting_cc_ua = 0;
532 return NEEDS_RETRY;
533 }
534 }
535 /*
536 * we might also expect a cc/ua if another LUN on the target
537 * reported a UA with an ASC/ASCQ of 3F 0E -
538 * REPORTED LUNS DATA HAS CHANGED.
539 */
540 if (scmd->device->sdev_target->expecting_lun_change &&
541 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
542 return NEEDS_RETRY;
543 /*
544 * if the device is in the process of becoming ready, we
545 * should retry.
546 */
547 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
548 return NEEDS_RETRY;
549 /*
550 * if the device is not started, we need to wake
551 * the error handler to start the motor
552 */
553 if (scmd->device->allow_restart &&
554 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
555 return FAILED;
556 /*
557 * Pass the UA upwards for a determination in the completion
558 * functions.
559 */
560 return SUCCESS;
561
562 /* these are not supported */
563 case DATA_PROTECT:
564 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
565 /* Thin provisioning hard threshold reached */
566 set_host_byte(scmd, DID_ALLOC_FAILURE);
567 return SUCCESS;
568 }
569 case COPY_ABORTED:
570 case VOLUME_OVERFLOW:
571 case MISCOMPARE:
572 case BLANK_CHECK:
573 set_host_byte(scmd, DID_TARGET_FAILURE);
574 return SUCCESS;
575
576 case MEDIUM_ERROR:
577 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
578 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
579 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
580 set_host_byte(scmd, DID_MEDIUM_ERROR);
581 return SUCCESS;
582 }
583 return NEEDS_RETRY;
584
585 case HARDWARE_ERROR:
586 if (scmd->device->retry_hwerror)
587 return ADD_TO_MLQUEUE;
588 else
589 set_host_byte(scmd, DID_TARGET_FAILURE);
590
591 case ILLEGAL_REQUEST:
592 if (sshdr.asc == 0x20 || /* Invalid command operation code */
593 sshdr.asc == 0x21 || /* Logical block address out of range */
594 sshdr.asc == 0x24 || /* Invalid field in cdb */
595 sshdr.asc == 0x26) { /* Parameter value invalid */
596 set_host_byte(scmd, DID_TARGET_FAILURE);
597 }
598 return SUCCESS;
599
600 default:
601 return SUCCESS;
602 }
603}
604
605static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
606{
607 struct scsi_host_template *sht = sdev->host->hostt;
608 struct scsi_device *tmp_sdev;
609
610 if (!sht->change_queue_depth ||
611 sdev->queue_depth >= sdev->max_queue_depth)
612 return;
613
614 if (time_before(jiffies,
615 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
616 return;
617
618 if (time_before(jiffies,
619 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
620 return;
621
622 /*
623 * Walk all devices of a target and do
624 * ramp up on them.
625 */
626 shost_for_each_device(tmp_sdev, sdev->host) {
627 if (tmp_sdev->channel != sdev->channel ||
628 tmp_sdev->id != sdev->id ||
629 tmp_sdev->queue_depth == sdev->max_queue_depth)
630 continue;
631 /*
632 * call back into LLD to increase queue_depth by one
633 * with ramp up reason code.
634 */
635 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
636 SCSI_QDEPTH_RAMP_UP);
637 sdev->last_queue_ramp_up = jiffies;
638 }
639}
640
641static void scsi_handle_queue_full(struct scsi_device *sdev)
642{
643 struct scsi_host_template *sht = sdev->host->hostt;
644 struct scsi_device *tmp_sdev;
645
646 if (!sht->change_queue_depth)
647 return;
648
649 shost_for_each_device(tmp_sdev, sdev->host) {
650 if (tmp_sdev->channel != sdev->channel ||
651 tmp_sdev->id != sdev->id)
652 continue;
653 /*
654 * We do not know the number of commands that were at
655 * the device when we got the queue full so we start
656 * from the highest possible value and work our way down.
657 */
658 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
659 SCSI_QDEPTH_QFULL);
660 }
661}
662
663/**
664 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
665 * @scmd: SCSI cmd to examine.
666 *
667 * Notes:
668 * This is *only* called when we are examining the status of commands
669 * queued during error recovery. the main difference here is that we
670 * don't allow for the possibility of retries here, and we are a lot
671 * more restrictive about what we consider acceptable.
672 */
673static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
674{
675 /*
676 * first check the host byte, to see if there is anything in there
677 * that would indicate what we need to do.
678 */
679 if (host_byte(scmd->result) == DID_RESET) {
680 /*
681 * rats. we are already in the error handler, so we now
682 * get to try and figure out what to do next. if the sense
683 * is valid, we have a pretty good idea of what to do.
684 * if not, we mark it as FAILED.
685 */
686 return scsi_check_sense(scmd);
687 }
688 if (host_byte(scmd->result) != DID_OK)
689 return FAILED;
690
691 /*
692 * next, check the message byte.
693 */
694 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
695 return FAILED;
696
697 /*
698 * now, check the status byte to see if this indicates
699 * anything special.
700 */
701 switch (status_byte(scmd->result)) {
702 case GOOD:
703 scsi_handle_queue_ramp_up(scmd->device);
704 case COMMAND_TERMINATED:
705 return SUCCESS;
706 case CHECK_CONDITION:
707 return scsi_check_sense(scmd);
708 case CONDITION_GOOD:
709 case INTERMEDIATE_GOOD:
710 case INTERMEDIATE_C_GOOD:
711 /*
712 * who knows? FIXME(eric)
713 */
714 return SUCCESS;
715 case RESERVATION_CONFLICT:
716 if (scmd->cmnd[0] == TEST_UNIT_READY)
717 /* it is a success, we probed the device and
718 * found it */
719 return SUCCESS;
720 /* otherwise, we failed to send the command */
721 return FAILED;
722 case QUEUE_FULL:
723 scsi_handle_queue_full(scmd->device);
724 /* fall through */
725 case BUSY:
726 return NEEDS_RETRY;
727 default:
728 return FAILED;
729 }
730 return FAILED;
731}
732
733/**
734 * scsi_eh_done - Completion function for error handling.
735 * @scmd: Cmd that is done.
736 */
737static void scsi_eh_done(struct scsi_cmnd *scmd)
738{
739 struct completion *eh_action;
740
741 SCSI_LOG_ERROR_RECOVERY(3,
742 printk("%s scmd: %p result: %x\n",
743 __func__, scmd, scmd->result));
744
745 eh_action = scmd->device->host->eh_action;
746 if (eh_action)
747 complete(eh_action);
748}
749
750/**
751 * scsi_try_host_reset - ask host adapter to reset itself
752 * @scmd: SCSI cmd to send host reset.
753 */
754static int scsi_try_host_reset(struct scsi_cmnd *scmd)
755{
756 unsigned long flags;
757 int rtn;
758 struct Scsi_Host *host = scmd->device->host;
759 struct scsi_host_template *hostt = host->hostt;
760
761 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
762 __func__));
763
764 if (!hostt->eh_host_reset_handler)
765 return FAILED;
766
767 rtn = hostt->eh_host_reset_handler(scmd);
768
769 if (rtn == SUCCESS) {
770 if (!hostt->skip_settle_delay)
771 ssleep(HOST_RESET_SETTLE_TIME);
772 spin_lock_irqsave(host->host_lock, flags);
773 scsi_report_bus_reset(host, scmd_channel(scmd));
774 spin_unlock_irqrestore(host->host_lock, flags);
775 }
776
777 return rtn;
778}
779
780/**
781 * scsi_try_bus_reset - ask host to perform a bus reset
782 * @scmd: SCSI cmd to send bus reset.
783 */
784static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
785{
786 unsigned long flags;
787 int rtn;
788 struct Scsi_Host *host = scmd->device->host;
789 struct scsi_host_template *hostt = host->hostt;
790
791 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
792 __func__));
793
794 if (!hostt->eh_bus_reset_handler)
795 return FAILED;
796
797 rtn = hostt->eh_bus_reset_handler(scmd);
798
799 if (rtn == SUCCESS) {
800 if (!hostt->skip_settle_delay)
801 ssleep(BUS_RESET_SETTLE_TIME);
802 spin_lock_irqsave(host->host_lock, flags);
803 scsi_report_bus_reset(host, scmd_channel(scmd));
804 spin_unlock_irqrestore(host->host_lock, flags);
805 }
806
807 return rtn;
808}
809
810static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
811{
812 sdev->was_reset = 1;
813 sdev->expecting_cc_ua = 1;
814}
815
816/**
817 * scsi_try_target_reset - Ask host to perform a target reset
818 * @scmd: SCSI cmd used to send a target reset
819 *
820 * Notes:
821 * There is no timeout for this operation. if this operation is
822 * unreliable for a given host, then the host itself needs to put a
823 * timer on it, and set the host back to a consistent state prior to
824 * returning.
825 */
826static int scsi_try_target_reset(struct scsi_cmnd *scmd)
827{
828 unsigned long flags;
829 int rtn;
830 struct Scsi_Host *host = scmd->device->host;
831 struct scsi_host_template *hostt = host->hostt;
832
833 if (!hostt->eh_target_reset_handler)
834 return FAILED;
835
836 rtn = hostt->eh_target_reset_handler(scmd);
837 if (rtn == SUCCESS) {
838 spin_lock_irqsave(host->host_lock, flags);
839 __starget_for_each_device(scsi_target(scmd->device), NULL,
840 __scsi_report_device_reset);
841 spin_unlock_irqrestore(host->host_lock, flags);
842 }
843
844 return rtn;
845}
846
847/**
848 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
849 * @scmd: SCSI cmd used to send BDR
850 *
851 * Notes:
852 * There is no timeout for this operation. if this operation is
853 * unreliable for a given host, then the host itself needs to put a
854 * timer on it, and set the host back to a consistent state prior to
855 * returning.
856 */
857static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
858{
859 int rtn;
860 struct scsi_host_template *hostt = scmd->device->host->hostt;
861
862 if (!hostt->eh_device_reset_handler)
863 return FAILED;
864
865 rtn = hostt->eh_device_reset_handler(scmd);
866 if (rtn == SUCCESS)
867 __scsi_report_device_reset(scmd->device, NULL);
868 return rtn;
869}
870
871static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
872{
873 if (!hostt->eh_abort_handler)
874 return FAILED;
875
876 return hostt->eh_abort_handler(scmd);
877}
878
879static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
880{
881 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
882 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
883 if (scsi_try_target_reset(scmd) != SUCCESS)
884 if (scsi_try_bus_reset(scmd) != SUCCESS)
885 scsi_try_host_reset(scmd);
886}
887
888/**
889 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
890 * @scmd: SCSI command structure to hijack
891 * @ses: structure to save restore information
892 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
893 * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
894 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
895 *
896 * This function is used to save a scsi command information before re-execution
897 * as part of the error recovery process. If @sense_bytes is 0 the command
898 * sent must be one that does not transfer any data. If @sense_bytes != 0
899 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
900 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
901 */
902void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
903 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
904{
905 struct scsi_device *sdev = scmd->device;
906
907 /*
908 * We need saved copies of a number of fields - this is because
909 * error handling may need to overwrite these with different values
910 * to run different commands, and once error handling is complete,
911 * we will need to restore these values prior to running the actual
912 * command.
913 */
914 ses->cmd_len = scmd->cmd_len;
915 ses->cmnd = scmd->cmnd;
916 ses->data_direction = scmd->sc_data_direction;
917 ses->sdb = scmd->sdb;
918 ses->next_rq = scmd->request->next_rq;
919 ses->result = scmd->result;
920 ses->underflow = scmd->underflow;
921 ses->prot_op = scmd->prot_op;
922
923 scmd->prot_op = SCSI_PROT_NORMAL;
924 scmd->eh_eflags = 0;
925 scmd->cmnd = ses->eh_cmnd;
926 memset(scmd->cmnd, 0, BLK_MAX_CDB);
927 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
928 scmd->request->next_rq = NULL;
929 scmd->result = 0;
930
931 if (sense_bytes) {
932 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
933 sense_bytes);
934 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
935 scmd->sdb.length);
936 scmd->sdb.table.sgl = &ses->sense_sgl;
937 scmd->sc_data_direction = DMA_FROM_DEVICE;
938 scmd->sdb.table.nents = 1;
939 scmd->cmnd[0] = REQUEST_SENSE;
940 scmd->cmnd[4] = scmd->sdb.length;
941 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
942 } else {
943 scmd->sc_data_direction = DMA_NONE;
944 if (cmnd) {
945 BUG_ON(cmnd_size > BLK_MAX_CDB);
946 memcpy(scmd->cmnd, cmnd, cmnd_size);
947 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
948 }
949 }
950
951 scmd->underflow = 0;
952
953 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
954 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
955 (sdev->lun << 5 & 0xe0);
956
957 /*
958 * Zero the sense buffer. The scsi spec mandates that any
959 * untransferred sense data should be interpreted as being zero.
960 */
961 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
962}
963EXPORT_SYMBOL(scsi_eh_prep_cmnd);
964
965/**
966 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
967 * @scmd: SCSI command structure to restore
968 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
969 *
970 * Undo any damage done by above scsi_eh_prep_cmnd().
971 */
972void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
973{
974 /*
975 * Restore original data
976 */
977 scmd->cmd_len = ses->cmd_len;
978 scmd->cmnd = ses->cmnd;
979 scmd->sc_data_direction = ses->data_direction;
980 scmd->sdb = ses->sdb;
981 scmd->request->next_rq = ses->next_rq;
982 scmd->result = ses->result;
983 scmd->underflow = ses->underflow;
984 scmd->prot_op = ses->prot_op;
985}
986EXPORT_SYMBOL(scsi_eh_restore_cmnd);
987
988/**
989 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
990 * @scmd: SCSI command structure to hijack
991 * @cmnd: CDB to send
992 * @cmnd_size: size in bytes of @cmnd
993 * @timeout: timeout for this request
994 * @sense_bytes: size of sense data to copy or 0
995 *
996 * This function is used to send a scsi command down to a target device
997 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
998 *
999 * Return value:
1000 * SUCCESS or FAILED or NEEDS_RETRY
1001 */
1002static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
1003 int cmnd_size, int timeout, unsigned sense_bytes)
1004{
1005 struct scsi_device *sdev = scmd->device;
1006 struct Scsi_Host *shost = sdev->host;
1007 DECLARE_COMPLETION_ONSTACK(done);
1008 unsigned long timeleft = timeout;
1009 struct scsi_eh_save ses;
1010 const unsigned long stall_for = msecs_to_jiffies(100);
1011 int rtn;
1012
1013retry:
1014 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1015 shost->eh_action = &done;
1016
1017 scsi_log_send(scmd);
1018 scmd->scsi_done = scsi_eh_done;
1019 rtn = shost->hostt->queuecommand(shost, scmd);
1020 if (rtn) {
1021 if (timeleft > stall_for) {
1022 scsi_eh_restore_cmnd(scmd, &ses);
1023 timeleft -= stall_for;
1024 msleep(jiffies_to_msecs(stall_for));
1025 goto retry;
1026 }
1027 /* signal not to enter either branch of the if () below */
1028 timeleft = 0;
1029 rtn = NEEDS_RETRY;
1030 } else {
1031 timeleft = wait_for_completion_timeout(&done, timeout);
1032 }
1033
1034 shost->eh_action = NULL;
1035
1036 scsi_log_completion(scmd, rtn);
1037
1038 SCSI_LOG_ERROR_RECOVERY(3,
1039 printk("%s: scmd: %p, timeleft: %ld\n",
1040 __func__, scmd, timeleft));
1041
1042 /*
1043 * If there is time left scsi_eh_done got called, and we will examine
1044 * the actual status codes to see whether the command actually did
1045 * complete normally, else if we have a zero return and no time left,
1046 * the command must still be pending, so abort it and return FAILED.
1047 * If we never actually managed to issue the command, because
1048 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1049 * value above (so don't execute either branch of the if)
1050 */
1051 if (timeleft) {
1052 rtn = scsi_eh_completed_normally(scmd);
1053 SCSI_LOG_ERROR_RECOVERY(3,
1054 printk("%s: scsi_eh_completed_normally %x\n",
1055 __func__, rtn));
1056
1057 switch (rtn) {
1058 case SUCCESS:
1059 case NEEDS_RETRY:
1060 case FAILED:
1061 break;
1062 case ADD_TO_MLQUEUE:
1063 rtn = NEEDS_RETRY;
1064 break;
1065 default:
1066 rtn = FAILED;
1067 break;
1068 }
1069 } else if (!rtn) {
1070 scsi_abort_eh_cmnd(scmd);
1071 rtn = FAILED;
1072 }
1073
1074 scsi_eh_restore_cmnd(scmd, &ses);
1075
1076 return rtn;
1077}
1078
1079/**
1080 * scsi_request_sense - Request sense data from a particular target.
1081 * @scmd: SCSI cmd for request sense.
1082 *
1083 * Notes:
1084 * Some hosts automatically obtain this information, others require
1085 * that we obtain it on our own. This function will *not* return until
1086 * the command either times out, or it completes.
1087 */
1088static int scsi_request_sense(struct scsi_cmnd *scmd)
1089{
1090 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1091}
1092
1093static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
1094{
1095 if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
1096 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1097 if (sdrv->eh_action)
1098 rtn = sdrv->eh_action(scmd, rtn);
1099 }
1100 return rtn;
1101}
1102
1103/**
1104 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1105 * @scmd: Original SCSI cmd that eh has finished.
1106 * @done_q: Queue for processed commands.
1107 *
1108 * Notes:
1109 * We don't want to use the normal command completion while we are are
1110 * still handling errors - it may cause other commands to be queued,
1111 * and that would disturb what we are doing. Thus we really want to
1112 * keep a list of pending commands for final completion, and once we
1113 * are ready to leave error handling we handle completion for real.
1114 */
1115void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1116{
1117 scmd->device->host->host_failed--;
1118 scmd->eh_eflags = 0;
1119 list_move_tail(&scmd->eh_entry, done_q);
1120}
1121EXPORT_SYMBOL(scsi_eh_finish_cmd);
1122
1123/**
1124 * scsi_eh_get_sense - Get device sense data.
1125 * @work_q: Queue of commands to process.
1126 * @done_q: Queue of processed commands.
1127 *
1128 * Description:
1129 * See if we need to request sense information. if so, then get it
1130 * now, so we have a better idea of what to do.
1131 *
1132 * Notes:
1133 * This has the unfortunate side effect that if a shost adapter does
1134 * not automatically request sense information, we end up shutting
1135 * it down before we request it.
1136 *
1137 * All drivers should request sense information internally these days,
1138 * so for now all I have to say is tough noogies if you end up in here.
1139 *
1140 * XXX: Long term this code should go away, but that needs an audit of
1141 * all LLDDs first.
1142 */
1143int scsi_eh_get_sense(struct list_head *work_q,
1144 struct list_head *done_q)
1145{
1146 struct scsi_cmnd *scmd, *next;
1147 struct Scsi_Host *shost;
1148 int rtn;
1149
1150 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1151 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
1152 SCSI_SENSE_VALID(scmd))
1153 continue;
1154
1155 shost = scmd->device->host;
1156 if (scsi_host_eh_past_deadline(shost)) {
1157 SCSI_LOG_ERROR_RECOVERY(3,
1158 shost_printk(KERN_INFO, shost,
1159 "skip %s, past eh deadline\n",
1160 __func__));
1161 break;
1162 }
1163 if (status_byte(scmd->result) != CHECK_CONDITION)
1164 /*
1165 * don't request sense if there's no check condition
1166 * status because the error we're processing isn't one
1167 * that has a sense code (and some devices get
1168 * confused by sense requests out of the blue)
1169 */
1170 continue;
1171
1172 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1173 "%s: requesting sense\n",
1174 current->comm));
1175 rtn = scsi_request_sense(scmd);
1176 if (rtn != SUCCESS)
1177 continue;
1178
1179 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
1180 " result %x\n", scmd,
1181 scmd->result));
1182 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
1183
1184 rtn = scsi_decide_disposition(scmd);
1185
1186 /*
1187 * if the result was normal, then just pass it along to the
1188 * upper level.
1189 */
1190 if (rtn == SUCCESS)
1191 /* we don't want this command reissued, just
1192 * finished with the sense data, so set
1193 * retries to the max allowed to ensure it
1194 * won't get reissued */
1195 scmd->retries = scmd->allowed;
1196 else if (rtn != NEEDS_RETRY)
1197 continue;
1198
1199 scsi_eh_finish_cmd(scmd, done_q);
1200 }
1201
1202 return list_empty(work_q);
1203}
1204EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1205
1206/**
1207 * scsi_eh_tur - Send TUR to device.
1208 * @scmd: &scsi_cmnd to send TUR
1209 *
1210 * Return value:
1211 * 0 - Device is ready. 1 - Device NOT ready.
1212 */
1213static int scsi_eh_tur(struct scsi_cmnd *scmd)
1214{
1215 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1216 int retry_cnt = 1, rtn;
1217
1218retry_tur:
1219 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1220 scmd->device->eh_timeout, 0);
1221
1222 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
1223 __func__, scmd, rtn));
1224
1225 switch (rtn) {
1226 case NEEDS_RETRY:
1227 if (retry_cnt--)
1228 goto retry_tur;
1229 /*FALLTHRU*/
1230 case SUCCESS:
1231 return 0;
1232 default:
1233 return 1;
1234 }
1235}
1236
1237/**
1238 * scsi_eh_test_devices - check if devices are responding from error recovery.
1239 * @cmd_list: scsi commands in error recovery.
1240 * @work_q: queue for commands which still need more error recovery
1241 * @done_q: queue for commands which are finished
1242 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1243 *
1244 * Decription:
1245 * Tests if devices are in a working state. Commands to devices now in
1246 * a working state are sent to the done_q while commands to devices which
1247 * are still failing to respond are returned to the work_q for more
1248 * processing.
1249 **/
1250static int scsi_eh_test_devices(struct list_head *cmd_list,
1251 struct list_head *work_q,
1252 struct list_head *done_q, int try_stu)
1253{
1254 struct scsi_cmnd *scmd, *next;
1255 struct scsi_device *sdev;
1256 int finish_cmds;
1257
1258 while (!list_empty(cmd_list)) {
1259 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1260 sdev = scmd->device;
1261
1262 if (!try_stu) {
1263 if (scsi_host_eh_past_deadline(sdev->host)) {
1264 /* Push items back onto work_q */
1265 list_splice_init(cmd_list, work_q);
1266 SCSI_LOG_ERROR_RECOVERY(3,
1267 shost_printk(KERN_INFO, sdev->host,
1268 "skip %s, past eh deadline",
1269 __func__));
1270 break;
1271 }
1272 }
1273
1274 finish_cmds = !scsi_device_online(scmd->device) ||
1275 (try_stu && !scsi_eh_try_stu(scmd) &&
1276 !scsi_eh_tur(scmd)) ||
1277 !scsi_eh_tur(scmd);
1278
1279 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1280 if (scmd->device == sdev) {
1281 if (finish_cmds &&
1282 (try_stu ||
1283 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1284 scsi_eh_finish_cmd(scmd, done_q);
1285 else
1286 list_move_tail(&scmd->eh_entry, work_q);
1287 }
1288 }
1289 return list_empty(work_q);
1290}
1291
1292
1293/**
1294 * scsi_eh_abort_cmds - abort pending commands.
1295 * @work_q: &list_head for pending commands.
1296 * @done_q: &list_head for processed commands.
1297 *
1298 * Decription:
1299 * Try and see whether or not it makes sense to try and abort the
1300 * running command. This only works out to be the case if we have one
1301 * command that has timed out. If the command simply failed, it makes
1302 * no sense to try and abort the command, since as far as the shost
1303 * adapter is concerned, it isn't running.
1304 */
1305static int scsi_eh_abort_cmds(struct list_head *work_q,
1306 struct list_head *done_q)
1307{
1308 struct scsi_cmnd *scmd, *next;
1309 LIST_HEAD(check_list);
1310 int rtn;
1311 struct Scsi_Host *shost;
1312
1313 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1314 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1315 continue;
1316 shost = scmd->device->host;
1317 if (scsi_host_eh_past_deadline(shost)) {
1318 list_splice_init(&check_list, work_q);
1319 SCSI_LOG_ERROR_RECOVERY(3,
1320 shost_printk(KERN_INFO, shost,
1321 "skip %s, past eh deadline\n",
1322 __func__));
1323 return list_empty(work_q);
1324 }
1325 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
1326 "0x%p\n", current->comm,
1327 scmd));
1328 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1329 if (rtn == FAILED) {
1330 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
1331 " cmd failed:"
1332 "0x%p\n",
1333 current->comm,
1334 scmd));
1335 list_splice_init(&check_list, work_q);
1336 return list_empty(work_q);
1337 }
1338 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1339 if (rtn == FAST_IO_FAIL)
1340 scsi_eh_finish_cmd(scmd, done_q);
1341 else
1342 list_move_tail(&scmd->eh_entry, &check_list);
1343 }
1344
1345 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1346}
1347
1348/**
1349 * scsi_eh_try_stu - Send START_UNIT to device.
1350 * @scmd: &scsi_cmnd to send START_UNIT
1351 *
1352 * Return value:
1353 * 0 - Device is ready. 1 - Device NOT ready.
1354 */
1355static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1356{
1357 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1358
1359 if (scmd->device->allow_restart) {
1360 int i, rtn = NEEDS_RETRY;
1361
1362 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1363 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1364
1365 if (rtn == SUCCESS)
1366 return 0;
1367 }
1368
1369 return 1;
1370}
1371
1372 /**
1373 * scsi_eh_stu - send START_UNIT if needed
1374 * @shost: &scsi host being recovered.
1375 * @work_q: &list_head for pending commands.
1376 * @done_q: &list_head for processed commands.
1377 *
1378 * Notes:
1379 * If commands are failing due to not ready, initializing command required,
1380 * try revalidating the device, which will end up sending a start unit.
1381 */
1382static int scsi_eh_stu(struct Scsi_Host *shost,
1383 struct list_head *work_q,
1384 struct list_head *done_q)
1385{
1386 struct scsi_cmnd *scmd, *stu_scmd, *next;
1387 struct scsi_device *sdev;
1388
1389 shost_for_each_device(sdev, shost) {
1390 if (scsi_host_eh_past_deadline(shost)) {
1391 SCSI_LOG_ERROR_RECOVERY(3,
1392 shost_printk(KERN_INFO, shost,
1393 "skip %s, past eh deadline\n",
1394 __func__));
1395 break;
1396 }
1397 stu_scmd = NULL;
1398 list_for_each_entry(scmd, work_q, eh_entry)
1399 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1400 scsi_check_sense(scmd) == FAILED ) {
1401 stu_scmd = scmd;
1402 break;
1403 }
1404
1405 if (!stu_scmd)
1406 continue;
1407
1408 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1409 " 0x%p\n", current->comm, sdev));
1410
1411 if (!scsi_eh_try_stu(stu_scmd)) {
1412 if (!scsi_device_online(sdev) ||
1413 !scsi_eh_tur(stu_scmd)) {
1414 list_for_each_entry_safe(scmd, next,
1415 work_q, eh_entry) {
1416 if (scmd->device == sdev &&
1417 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1418 scsi_eh_finish_cmd(scmd, done_q);
1419 }
1420 }
1421 } else {
1422 SCSI_LOG_ERROR_RECOVERY(3,
1423 printk("%s: START_UNIT failed to sdev:"
1424 " 0x%p\n", current->comm, sdev));
1425 }
1426 }
1427
1428 return list_empty(work_q);
1429}
1430
1431
1432/**
1433 * scsi_eh_bus_device_reset - send bdr if needed
1434 * @shost: scsi host being recovered.
1435 * @work_q: &list_head for pending commands.
1436 * @done_q: &list_head for processed commands.
1437 *
1438 * Notes:
1439 * Try a bus device reset. Still, look to see whether we have multiple
1440 * devices that are jammed or not - if we have multiple devices, it
1441 * makes no sense to try bus_device_reset - we really would need to try
1442 * a bus_reset instead.
1443 */
1444static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1445 struct list_head *work_q,
1446 struct list_head *done_q)
1447{
1448 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1449 struct scsi_device *sdev;
1450 int rtn;
1451
1452 shost_for_each_device(sdev, shost) {
1453 if (scsi_host_eh_past_deadline(shost)) {
1454 SCSI_LOG_ERROR_RECOVERY(3,
1455 shost_printk(KERN_INFO, shost,
1456 "skip %s, past eh deadline\n",
1457 __func__));
1458 break;
1459 }
1460 bdr_scmd = NULL;
1461 list_for_each_entry(scmd, work_q, eh_entry)
1462 if (scmd->device == sdev) {
1463 bdr_scmd = scmd;
1464 break;
1465 }
1466
1467 if (!bdr_scmd)
1468 continue;
1469
1470 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1471 " 0x%p\n", current->comm,
1472 sdev));
1473 rtn = scsi_try_bus_device_reset(bdr_scmd);
1474 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1475 if (!scsi_device_online(sdev) ||
1476 rtn == FAST_IO_FAIL ||
1477 !scsi_eh_tur(bdr_scmd)) {
1478 list_for_each_entry_safe(scmd, next,
1479 work_q, eh_entry) {
1480 if (scmd->device == sdev &&
1481 scsi_eh_action(scmd, rtn) != FAILED)
1482 scsi_eh_finish_cmd(scmd,
1483 done_q);
1484 }
1485 }
1486 } else {
1487 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1488 " failed sdev:"
1489 "0x%p\n",
1490 current->comm,
1491 sdev));
1492 }
1493 }
1494
1495 return list_empty(work_q);
1496}
1497
1498/**
1499 * scsi_eh_target_reset - send target reset if needed
1500 * @shost: scsi host being recovered.
1501 * @work_q: &list_head for pending commands.
1502 * @done_q: &list_head for processed commands.
1503 *
1504 * Notes:
1505 * Try a target reset.
1506 */
1507static int scsi_eh_target_reset(struct Scsi_Host *shost,
1508 struct list_head *work_q,
1509 struct list_head *done_q)
1510{
1511 LIST_HEAD(tmp_list);
1512 LIST_HEAD(check_list);
1513
1514 list_splice_init(work_q, &tmp_list);
1515
1516 while (!list_empty(&tmp_list)) {
1517 struct scsi_cmnd *next, *scmd;
1518 int rtn;
1519 unsigned int id;
1520
1521 if (scsi_host_eh_past_deadline(shost)) {
1522 /* push back on work queue for further processing */
1523 list_splice_init(&check_list, work_q);
1524 list_splice_init(&tmp_list, work_q);
1525 SCSI_LOG_ERROR_RECOVERY(3,
1526 shost_printk(KERN_INFO, shost,
1527 "skip %s, past eh deadline\n",
1528 __func__));
1529 return list_empty(work_q);
1530 }
1531
1532 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1533 id = scmd_id(scmd);
1534
1535 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1536 "to target %d\n",
1537 current->comm, id));
1538 rtn = scsi_try_target_reset(scmd);
1539 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1540 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1541 " failed target: "
1542 "%d\n",
1543 current->comm, id));
1544 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1545 if (scmd_id(scmd) != id)
1546 continue;
1547
1548 if (rtn == SUCCESS)
1549 list_move_tail(&scmd->eh_entry, &check_list);
1550 else if (rtn == FAST_IO_FAIL)
1551 scsi_eh_finish_cmd(scmd, done_q);
1552 else
1553 /* push back on work queue for further processing */
1554 list_move(&scmd->eh_entry, work_q);
1555 }
1556 }
1557
1558 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1559}
1560
1561/**
1562 * scsi_eh_bus_reset - send a bus reset
1563 * @shost: &scsi host being recovered.
1564 * @work_q: &list_head for pending commands.
1565 * @done_q: &list_head for processed commands.
1566 */
1567static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1568 struct list_head *work_q,
1569 struct list_head *done_q)
1570{
1571 struct scsi_cmnd *scmd, *chan_scmd, *next;
1572 LIST_HEAD(check_list);
1573 unsigned int channel;
1574 int rtn;
1575
1576 /*
1577 * we really want to loop over the various channels, and do this on
1578 * a channel by channel basis. we should also check to see if any
1579 * of the failed commands are on soft_reset devices, and if so, skip
1580 * the reset.
1581 */
1582
1583 for (channel = 0; channel <= shost->max_channel; channel++) {
1584 if (scsi_host_eh_past_deadline(shost)) {
1585 list_splice_init(&check_list, work_q);
1586 SCSI_LOG_ERROR_RECOVERY(3,
1587 shost_printk(KERN_INFO, shost,
1588 "skip %s, past eh deadline\n",
1589 __func__));
1590 return list_empty(work_q);
1591 }
1592
1593 chan_scmd = NULL;
1594 list_for_each_entry(scmd, work_q, eh_entry) {
1595 if (channel == scmd_channel(scmd)) {
1596 chan_scmd = scmd;
1597 break;
1598 /*
1599 * FIXME add back in some support for
1600 * soft_reset devices.
1601 */
1602 }
1603 }
1604
1605 if (!chan_scmd)
1606 continue;
1607 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1608 " %d\n", current->comm,
1609 channel));
1610 rtn = scsi_try_bus_reset(chan_scmd);
1611 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1612 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1613 if (channel == scmd_channel(scmd)) {
1614 if (rtn == FAST_IO_FAIL)
1615 scsi_eh_finish_cmd(scmd,
1616 done_q);
1617 else
1618 list_move_tail(&scmd->eh_entry,
1619 &check_list);
1620 }
1621 }
1622 } else {
1623 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1624 " failed chan: %d\n",
1625 current->comm,
1626 channel));
1627 }
1628 }
1629 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1630}
1631
1632/**
1633 * scsi_eh_host_reset - send a host reset
1634 * @work_q: list_head for processed commands.
1635 * @done_q: list_head for processed commands.
1636 */
1637static int scsi_eh_host_reset(struct list_head *work_q,
1638 struct list_head *done_q)
1639{
1640 struct scsi_cmnd *scmd, *next;
1641 LIST_HEAD(check_list);
1642 int rtn;
1643
1644 if (!list_empty(work_q)) {
1645 scmd = list_entry(work_q->next,
1646 struct scsi_cmnd, eh_entry);
1647
1648 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1649 , current->comm));
1650
1651 rtn = scsi_try_host_reset(scmd);
1652 if (rtn == SUCCESS) {
1653 list_splice_init(work_q, &check_list);
1654 } else if (rtn == FAST_IO_FAIL) {
1655 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1656 scsi_eh_finish_cmd(scmd, done_q);
1657 }
1658 } else {
1659 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1660 " failed\n",
1661 current->comm));
1662 }
1663 }
1664 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1665}
1666
1667/**
1668 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1669 * @work_q: list_head for processed commands.
1670 * @done_q: list_head for processed commands.
1671 */
1672static void scsi_eh_offline_sdevs(struct list_head *work_q,
1673 struct list_head *done_q)
1674{
1675 struct scsi_cmnd *scmd, *next;
1676
1677 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1678 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1679 "not ready after error recovery\n");
1680 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1681 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1682 /*
1683 * FIXME: Handle lost cmds.
1684 */
1685 }
1686 scsi_eh_finish_cmd(scmd, done_q);
1687 }
1688 return;
1689}
1690
1691/**
1692 * scsi_noretry_cmd - determine if command should be failed fast
1693 * @scmd: SCSI cmd to examine.
1694 */
1695int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1696{
1697 switch (host_byte(scmd->result)) {
1698 case DID_OK:
1699 break;
1700 case DID_TIME_OUT:
1701 goto check_type;
1702 case DID_BUS_BUSY:
1703 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1704 case DID_PARITY:
1705 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1706 case DID_ERROR:
1707 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1708 status_byte(scmd->result) == RESERVATION_CONFLICT)
1709 return 0;
1710 /* fall through */
1711 case DID_SOFT_ERROR:
1712 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1713 }
1714
1715 if (status_byte(scmd->result) != CHECK_CONDITION)
1716 return 0;
1717
1718check_type:
1719 /*
1720 * assume caller has checked sense and determined
1721 * the check condition was retryable.
1722 */
1723 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1724 scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1725 return 1;
1726 else
1727 return 0;
1728}
1729
1730/**
1731 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1732 * @scmd: SCSI cmd to examine.
1733 *
1734 * Notes:
1735 * This is *only* called when we are examining the status after sending
1736 * out the actual data command. any commands that are queued for error
1737 * recovery (e.g. test_unit_ready) do *not* come through here.
1738 *
1739 * When this routine returns failed, it means the error handler thread
1740 * is woken. In cases where the error code indicates an error that
1741 * doesn't require the error handler read (i.e. we don't need to
1742 * abort/reset), this function should return SUCCESS.
1743 */
1744int scsi_decide_disposition(struct scsi_cmnd *scmd)
1745{
1746 int rtn;
1747
1748 /*
1749 * if the device is offline, then we clearly just pass the result back
1750 * up to the top level.
1751 */
1752 if (!scsi_device_online(scmd->device)) {
1753 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1754 " as SUCCESS\n",
1755 __func__));
1756 return SUCCESS;
1757 }
1758
1759 /*
1760 * first check the host byte, to see if there is anything in there
1761 * that would indicate what we need to do.
1762 */
1763 switch (host_byte(scmd->result)) {
1764 case DID_PASSTHROUGH:
1765 /*
1766 * no matter what, pass this through to the upper layer.
1767 * nuke this special code so that it looks like we are saying
1768 * did_ok.
1769 */
1770 scmd->result &= 0xff00ffff;
1771 return SUCCESS;
1772 case DID_OK:
1773 /*
1774 * looks good. drop through, and check the next byte.
1775 */
1776 break;
1777 case DID_ABORT:
1778 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1779 scmd->result |= DID_TIME_OUT << 16;
1780 return SUCCESS;
1781 }
1782 case DID_NO_CONNECT:
1783 case DID_BAD_TARGET:
1784 /*
1785 * note - this means that we just report the status back
1786 * to the top level driver, not that we actually think
1787 * that it indicates SUCCESS.
1788 */
1789 return SUCCESS;
1790 /*
1791 * when the low level driver returns did_soft_error,
1792 * it is responsible for keeping an internal retry counter
1793 * in order to avoid endless loops (db)
1794 *
1795 * actually this is a bug in this function here. we should
1796 * be mindful of the maximum number of retries specified
1797 * and not get stuck in a loop.
1798 */
1799 case DID_SOFT_ERROR:
1800 goto maybe_retry;
1801 case DID_IMM_RETRY:
1802 return NEEDS_RETRY;
1803
1804 case DID_REQUEUE:
1805 return ADD_TO_MLQUEUE;
1806 case DID_TRANSPORT_DISRUPTED:
1807 /*
1808 * LLD/transport was disrupted during processing of the IO.
1809 * The transport class is now blocked/blocking,
1810 * and the transport will decide what to do with the IO
1811 * based on its timers and recovery capablilities if
1812 * there are enough retries.
1813 */
1814 goto maybe_retry;
1815 case DID_TRANSPORT_FAILFAST:
1816 /*
1817 * The transport decided to failfast the IO (most likely
1818 * the fast io fail tmo fired), so send IO directly upwards.
1819 */
1820 return SUCCESS;
1821 case DID_ERROR:
1822 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1823 status_byte(scmd->result) == RESERVATION_CONFLICT)
1824 /*
1825 * execute reservation conflict processing code
1826 * lower down
1827 */
1828 break;
1829 /* fallthrough */
1830 case DID_BUS_BUSY:
1831 case DID_PARITY:
1832 goto maybe_retry;
1833 case DID_TIME_OUT:
1834 /*
1835 * when we scan the bus, we get timeout messages for
1836 * these commands if there is no device available.
1837 * other hosts report did_no_connect for the same thing.
1838 */
1839 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1840 scmd->cmnd[0] == INQUIRY)) {
1841 return SUCCESS;
1842 } else {
1843 return FAILED;
1844 }
1845 case DID_RESET:
1846 return SUCCESS;
1847 default:
1848 return FAILED;
1849 }
1850
1851 /*
1852 * next, check the message byte.
1853 */
1854 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1855 return FAILED;
1856
1857 /*
1858 * check the status byte to see if this indicates anything special.
1859 */
1860 switch (status_byte(scmd->result)) {
1861 case QUEUE_FULL:
1862 scsi_handle_queue_full(scmd->device);
1863 /*
1864 * the case of trying to send too many commands to a
1865 * tagged queueing device.
1866 */
1867 case BUSY:
1868 /*
1869 * device can't talk to us at the moment. Should only
1870 * occur (SAM-3) when the task queue is empty, so will cause
1871 * the empty queue handling to trigger a stall in the
1872 * device.
1873 */
1874 return ADD_TO_MLQUEUE;
1875 case GOOD:
1876 if (scmd->cmnd[0] == REPORT_LUNS)
1877 scmd->device->sdev_target->expecting_lun_change = 0;
1878 scsi_handle_queue_ramp_up(scmd->device);
1879 case COMMAND_TERMINATED:
1880 return SUCCESS;
1881 case TASK_ABORTED:
1882 goto maybe_retry;
1883 case CHECK_CONDITION:
1884 rtn = scsi_check_sense(scmd);
1885 if (rtn == NEEDS_RETRY)
1886 goto maybe_retry;
1887 /* if rtn == FAILED, we have no sense information;
1888 * returning FAILED will wake the error handler thread
1889 * to collect the sense and redo the decide
1890 * disposition */
1891 return rtn;
1892 case CONDITION_GOOD:
1893 case INTERMEDIATE_GOOD:
1894 case INTERMEDIATE_C_GOOD:
1895 case ACA_ACTIVE:
1896 /*
1897 * who knows? FIXME(eric)
1898 */
1899 return SUCCESS;
1900
1901 case RESERVATION_CONFLICT:
1902 sdev_printk(KERN_INFO, scmd->device,
1903 "reservation conflict\n");
1904 set_host_byte(scmd, DID_NEXUS_FAILURE);
1905 return SUCCESS; /* causes immediate i/o error */
1906 default:
1907 return FAILED;
1908 }
1909 return FAILED;
1910
1911 maybe_retry:
1912
1913 /* we requeue for retry because the error was retryable, and
1914 * the request was not marked fast fail. Note that above,
1915 * even if the request is marked fast fail, we still requeue
1916 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1917 if ((++scmd->retries) <= scmd->allowed
1918 && !scsi_noretry_cmd(scmd)) {
1919 return NEEDS_RETRY;
1920 } else {
1921 /*
1922 * no more retries - report this one back to upper level.
1923 */
1924 return SUCCESS;
1925 }
1926}
1927
1928static void eh_lock_door_done(struct request *req, int uptodate)
1929{
1930 __blk_put_request(req->q, req);
1931}
1932
1933/**
1934 * scsi_eh_lock_door - Prevent medium removal for the specified device
1935 * @sdev: SCSI device to prevent medium removal
1936 *
1937 * Locking:
1938 * We must be called from process context.
1939 *
1940 * Notes:
1941 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1942 * head of the devices request queue, and continue.
1943 */
1944static void scsi_eh_lock_door(struct scsi_device *sdev)
1945{
1946 struct request *req;
1947
1948 /*
1949 * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1950 * request becomes available
1951 */
1952 req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1953
1954 req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1955 req->cmd[1] = 0;
1956 req->cmd[2] = 0;
1957 req->cmd[3] = 0;
1958 req->cmd[4] = SCSI_REMOVAL_PREVENT;
1959 req->cmd[5] = 0;
1960
1961 req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1962
1963 req->cmd_type = REQ_TYPE_BLOCK_PC;
1964 req->cmd_flags |= REQ_QUIET;
1965 req->timeout = 10 * HZ;
1966 req->retries = 5;
1967
1968 blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1969}
1970
1971/**
1972 * scsi_restart_operations - restart io operations to the specified host.
1973 * @shost: Host we are restarting.
1974 *
1975 * Notes:
1976 * When we entered the error handler, we blocked all further i/o to
1977 * this device. we need to 'reverse' this process.
1978 */
1979static void scsi_restart_operations(struct Scsi_Host *shost)
1980{
1981 struct scsi_device *sdev;
1982 unsigned long flags;
1983
1984 /*
1985 * If the door was locked, we need to insert a door lock request
1986 * onto the head of the SCSI request queue for the device. There
1987 * is no point trying to lock the door of an off-line device.
1988 */
1989 shost_for_each_device(sdev, shost) {
1990 if (scsi_device_online(sdev) && sdev->locked)
1991 scsi_eh_lock_door(sdev);
1992 }
1993
1994 /*
1995 * next free up anything directly waiting upon the host. this
1996 * will be requests for character device operations, and also for
1997 * ioctls to queued block devices.
1998 */
1999 SCSI_LOG_ERROR_RECOVERY(3,
2000 printk("scsi_eh_%d waking up host to restart\n",
2001 shost->host_no));
2002
2003 spin_lock_irqsave(shost->host_lock, flags);
2004 if (scsi_host_set_state(shost, SHOST_RUNNING))
2005 if (scsi_host_set_state(shost, SHOST_CANCEL))
2006 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2007 spin_unlock_irqrestore(shost->host_lock, flags);
2008
2009 wake_up(&shost->host_wait);
2010
2011 /*
2012 * finally we need to re-initiate requests that may be pending. we will
2013 * have had everything blocked while error handling is taking place, and
2014 * now that error recovery is done, we will need to ensure that these
2015 * requests are started.
2016 */
2017 scsi_run_host_queues(shost);
2018
2019 /*
2020 * if eh is active and host_eh_scheduled is pending we need to re-run
2021 * recovery. we do this check after scsi_run_host_queues() to allow
2022 * everything pent up since the last eh run a chance to make forward
2023 * progress before we sync again. Either we'll immediately re-run
2024 * recovery or scsi_device_unbusy() will wake us again when these
2025 * pending commands complete.
2026 */
2027 spin_lock_irqsave(shost->host_lock, flags);
2028 if (shost->host_eh_scheduled)
2029 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2030 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2031 spin_unlock_irqrestore(shost->host_lock, flags);
2032}
2033
2034/**
2035 * scsi_eh_ready_devs - check device ready state and recover if not.
2036 * @shost: host to be recovered.
2037 * @work_q: &list_head for pending commands.
2038 * @done_q: &list_head for processed commands.
2039 */
2040void scsi_eh_ready_devs(struct Scsi_Host *shost,
2041 struct list_head *work_q,
2042 struct list_head *done_q)
2043{
2044 if (!scsi_eh_stu(shost, work_q, done_q))
2045 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2046 if (!scsi_eh_target_reset(shost, work_q, done_q))
2047 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2048 if (!scsi_eh_host_reset(work_q, done_q))
2049 scsi_eh_offline_sdevs(work_q,
2050 done_q);
2051}
2052EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2053
2054/**
2055 * scsi_eh_flush_done_q - finish processed commands or retry them.
2056 * @done_q: list_head of processed commands.
2057 */
2058void scsi_eh_flush_done_q(struct list_head *done_q)
2059{
2060 struct scsi_cmnd *scmd, *next;
2061
2062 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2063 list_del_init(&scmd->eh_entry);
2064 if (scsi_device_online(scmd->device) &&
2065 !scsi_noretry_cmd(scmd) &&
2066 (++scmd->retries <= scmd->allowed)) {
2067 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
2068 " retry cmd: %p\n",
2069 current->comm,
2070 scmd));
2071 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2072 } else {
2073 /*
2074 * If just we got sense for the device (called
2075 * scsi_eh_get_sense), scmd->result is already
2076 * set, do not set DRIVER_TIMEOUT.
2077 */
2078 if (!scmd->result)
2079 scmd->result |= (DRIVER_TIMEOUT << 24);
2080 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
2081 " cmd: %p\n",
2082 current->comm, scmd));
2083 scsi_finish_command(scmd);
2084 }
2085 }
2086}
2087EXPORT_SYMBOL(scsi_eh_flush_done_q);
2088
2089/**
2090 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2091 * @shost: Host to unjam.
2092 *
2093 * Notes:
2094 * When we come in here, we *know* that all commands on the bus have
2095 * either completed, failed or timed out. we also know that no further
2096 * commands are being sent to the host, so things are relatively quiet
2097 * and we have freedom to fiddle with things as we wish.
2098 *
2099 * This is only the *default* implementation. it is possible for
2100 * individual drivers to supply their own version of this function, and
2101 * if the maintainer wishes to do this, it is strongly suggested that
2102 * this function be taken as a template and modified. this function
2103 * was designed to correctly handle problems for about 95% of the
2104 * different cases out there, and it should always provide at least a
2105 * reasonable amount of error recovery.
2106 *
2107 * Any command marked 'failed' or 'timeout' must eventually have
2108 * scsi_finish_cmd() called for it. we do all of the retry stuff
2109 * here, so when we restart the host after we return it should have an
2110 * empty queue.
2111 */
2112static void scsi_unjam_host(struct Scsi_Host *shost)
2113{
2114 unsigned long flags;
2115 LIST_HEAD(eh_work_q);
2116 LIST_HEAD(eh_done_q);
2117
2118 spin_lock_irqsave(shost->host_lock, flags);
2119 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2120 spin_unlock_irqrestore(shost->host_lock, flags);
2121
2122 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2123
2124 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2125 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
2126 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2127
2128 spin_lock_irqsave(shost->host_lock, flags);
2129 if (shost->eh_deadline != -1)
2130 shost->last_reset = 0;
2131 spin_unlock_irqrestore(shost->host_lock, flags);
2132 scsi_eh_flush_done_q(&eh_done_q);
2133}
2134
2135/**
2136 * scsi_error_handler - SCSI error handler thread
2137 * @data: Host for which we are running.
2138 *
2139 * Notes:
2140 * This is the main error handling loop. This is run as a kernel thread
2141 * for every SCSI host and handles all error handling activity.
2142 */
2143int scsi_error_handler(void *data)
2144{
2145 struct Scsi_Host *shost = data;
2146
2147 /*
2148 * We use TASK_INTERRUPTIBLE so that the thread is not
2149 * counted against the load average as a running process.
2150 * We never actually get interrupted because kthread_run
2151 * disables signal delivery for the created thread.
2152 */
2153 while (!kthread_should_stop()) {
2154 set_current_state(TASK_INTERRUPTIBLE);
2155 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2156 shost->host_failed != shost->host_busy) {
2157 SCSI_LOG_ERROR_RECOVERY(1,
2158 printk("scsi_eh_%d: sleeping\n",
2159 shost->host_no));
2160 schedule();
2161 continue;
2162 }
2163
2164 __set_current_state(TASK_RUNNING);
2165 SCSI_LOG_ERROR_RECOVERY(1,
2166 printk("scsi_eh_%d: waking up %d/%d/%d\n",
2167 shost->host_no, shost->host_eh_scheduled,
2168 shost->host_failed, shost->host_busy));
2169
2170 /*
2171 * We have a host that is failing for some reason. Figure out
2172 * what we need to do to get it up and online again (if we can).
2173 * If we fail, we end up taking the thing offline.
2174 */
2175 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2176 SCSI_LOG_ERROR_RECOVERY(1,
2177 printk(KERN_ERR "Error handler scsi_eh_%d "
2178 "unable to autoresume\n",
2179 shost->host_no));
2180 continue;
2181 }
2182
2183 if (shost->transportt->eh_strategy_handler)
2184 shost->transportt->eh_strategy_handler(shost);
2185 else
2186 scsi_unjam_host(shost);
2187
2188 /*
2189 * Note - if the above fails completely, the action is to take
2190 * individual devices offline and flush the queue of any
2191 * outstanding requests that may have been pending. When we
2192 * restart, we restart any I/O to any other devices on the bus
2193 * which are still online.
2194 */
2195 scsi_restart_operations(shost);
2196 if (!shost->eh_noresume)
2197 scsi_autopm_put_host(shost);
2198 }
2199 __set_current_state(TASK_RUNNING);
2200
2201 SCSI_LOG_ERROR_RECOVERY(1,
2202 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
2203 shost->ehandler = NULL;
2204 return 0;
2205}
2206
2207/*
2208 * Function: scsi_report_bus_reset()
2209 *
2210 * Purpose: Utility function used by low-level drivers to report that
2211 * they have observed a bus reset on the bus being handled.
2212 *
2213 * Arguments: shost - Host in question
2214 * channel - channel on which reset was observed.
2215 *
2216 * Returns: Nothing
2217 *
2218 * Lock status: Host lock must be held.
2219 *
2220 * Notes: This only needs to be called if the reset is one which
2221 * originates from an unknown location. Resets originated
2222 * by the mid-level itself don't need to call this, but there
2223 * should be no harm.
2224 *
2225 * The main purpose of this is to make sure that a CHECK_CONDITION
2226 * is properly treated.
2227 */
2228void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2229{
2230 struct scsi_device *sdev;
2231
2232 __shost_for_each_device(sdev, shost) {
2233 if (channel == sdev_channel(sdev))
2234 __scsi_report_device_reset(sdev, NULL);
2235 }
2236}
2237EXPORT_SYMBOL(scsi_report_bus_reset);
2238
2239/*
2240 * Function: scsi_report_device_reset()
2241 *
2242 * Purpose: Utility function used by low-level drivers to report that
2243 * they have observed a device reset on the device being handled.
2244 *
2245 * Arguments: shost - Host in question
2246 * channel - channel on which reset was observed
2247 * target - target on which reset was observed
2248 *
2249 * Returns: Nothing
2250 *
2251 * Lock status: Host lock must be held
2252 *
2253 * Notes: This only needs to be called if the reset is one which
2254 * originates from an unknown location. Resets originated
2255 * by the mid-level itself don't need to call this, but there
2256 * should be no harm.
2257 *
2258 * The main purpose of this is to make sure that a CHECK_CONDITION
2259 * is properly treated.
2260 */
2261void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2262{
2263 struct scsi_device *sdev;
2264
2265 __shost_for_each_device(sdev, shost) {
2266 if (channel == sdev_channel(sdev) &&
2267 target == sdev_id(sdev))
2268 __scsi_report_device_reset(sdev, NULL);
2269 }
2270}
2271EXPORT_SYMBOL(scsi_report_device_reset);
2272
2273static void
2274scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2275{
2276}
2277
2278/*
2279 * Function: scsi_reset_provider
2280 *
2281 * Purpose: Send requested reset to a bus or device at any phase.
2282 *
2283 * Arguments: device - device to send reset to
2284 * flag - reset type (see scsi.h)
2285 *
2286 * Returns: SUCCESS/FAILURE.
2287 *
2288 * Notes: This is used by the SCSI Generic driver to provide
2289 * Bus/Device reset capability.
2290 */
2291int
2292scsi_reset_provider(struct scsi_device *dev, int flag)
2293{
2294 struct scsi_cmnd *scmd;
2295 struct Scsi_Host *shost = dev->host;
2296 struct request req;
2297 unsigned long flags;
2298 int rtn;
2299
2300 if (scsi_autopm_get_host(shost) < 0)
2301 return FAILED;
2302
2303 if (!get_device(&dev->sdev_gendev)) {
2304 rtn = FAILED;
2305 goto out_put_autopm_host;
2306 }
2307
2308 scmd = scsi_get_command(dev, GFP_KERNEL);
2309 blk_rq_init(NULL, &req);
2310 scmd->request = &req;
2311
2312 scmd->cmnd = req.cmd;
2313
2314 scmd->scsi_done = scsi_reset_provider_done_command;
2315 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2316
2317 scmd->cmd_len = 0;
2318
2319 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2320
2321 spin_lock_irqsave(shost->host_lock, flags);
2322 shost->tmf_in_progress = 1;
2323 spin_unlock_irqrestore(shost->host_lock, flags);
2324
2325 switch (flag) {
2326 case SCSI_TRY_RESET_DEVICE:
2327 rtn = scsi_try_bus_device_reset(scmd);
2328 if (rtn == SUCCESS)
2329 break;
2330 /* FALLTHROUGH */
2331 case SCSI_TRY_RESET_TARGET:
2332 rtn = scsi_try_target_reset(scmd);
2333 if (rtn == SUCCESS)
2334 break;
2335 /* FALLTHROUGH */
2336 case SCSI_TRY_RESET_BUS:
2337 rtn = scsi_try_bus_reset(scmd);
2338 if (rtn == SUCCESS)
2339 break;
2340 /* FALLTHROUGH */
2341 case SCSI_TRY_RESET_HOST:
2342 rtn = scsi_try_host_reset(scmd);
2343 break;
2344 default:
2345 rtn = FAILED;
2346 }
2347
2348 spin_lock_irqsave(shost->host_lock, flags);
2349 shost->tmf_in_progress = 0;
2350 spin_unlock_irqrestore(shost->host_lock, flags);
2351
2352 /*
2353 * be sure to wake up anyone who was sleeping or had their queue
2354 * suspended while we performed the TMF.
2355 */
2356 SCSI_LOG_ERROR_RECOVERY(3,
2357 printk("%s: waking up host to restart after TMF\n",
2358 __func__));
2359
2360 wake_up(&shost->host_wait);
2361
2362 scsi_run_host_queues(shost);
2363
2364 scsi_next_command(scmd);
2365out_put_autopm_host:
2366 scsi_autopm_put_host(shost);
2367 return rtn;
2368}
2369EXPORT_SYMBOL(scsi_reset_provider);
2370
2371/**
2372 * scsi_normalize_sense - normalize main elements from either fixed or
2373 * descriptor sense data format into a common format.
2374 *
2375 * @sense_buffer: byte array containing sense data returned by device
2376 * @sb_len: number of valid bytes in sense_buffer
2377 * @sshdr: pointer to instance of structure that common
2378 * elements are written to.
2379 *
2380 * Notes:
2381 * The "main elements" from sense data are: response_code, sense_key,
2382 * asc, ascq and additional_length (only for descriptor format).
2383 *
2384 * Typically this function can be called after a device has
2385 * responded to a SCSI command with the CHECK_CONDITION status.
2386 *
2387 * Return value:
2388 * 1 if valid sense data information found, else 0;
2389 */
2390int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
2391 struct scsi_sense_hdr *sshdr)
2392{
2393 if (!sense_buffer || !sb_len)
2394 return 0;
2395
2396 memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
2397
2398 sshdr->response_code = (sense_buffer[0] & 0x7f);
2399
2400 if (!scsi_sense_valid(sshdr))
2401 return 0;
2402
2403 if (sshdr->response_code >= 0x72) {
2404 /*
2405 * descriptor format
2406 */
2407 if (sb_len > 1)
2408 sshdr->sense_key = (sense_buffer[1] & 0xf);
2409 if (sb_len > 2)
2410 sshdr->asc = sense_buffer[2];
2411 if (sb_len > 3)
2412 sshdr->ascq = sense_buffer[3];
2413 if (sb_len > 7)
2414 sshdr->additional_length = sense_buffer[7];
2415 } else {
2416 /*
2417 * fixed format
2418 */
2419 if (sb_len > 2)
2420 sshdr->sense_key = (sense_buffer[2] & 0xf);
2421 if (sb_len > 7) {
2422 sb_len = (sb_len < (sense_buffer[7] + 8)) ?
2423 sb_len : (sense_buffer[7] + 8);
2424 if (sb_len > 12)
2425 sshdr->asc = sense_buffer[12];
2426 if (sb_len > 13)
2427 sshdr->ascq = sense_buffer[13];
2428 }
2429 }
2430
2431 return 1;
2432}
2433EXPORT_SYMBOL(scsi_normalize_sense);
2434
2435int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
2436 struct scsi_sense_hdr *sshdr)
2437{
2438 return scsi_normalize_sense(cmd->sense_buffer,
2439 SCSI_SENSE_BUFFERSIZE, sshdr);
2440}
2441EXPORT_SYMBOL(scsi_command_normalize_sense);
2442
2443/**
2444 * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
2445 * @sense_buffer: byte array of descriptor format sense data
2446 * @sb_len: number of valid bytes in sense_buffer
2447 * @desc_type: value of descriptor type to find
2448 * (e.g. 0 -> information)
2449 *
2450 * Notes:
2451 * only valid when sense data is in descriptor format
2452 *
2453 * Return value:
2454 * pointer to start of (first) descriptor if found else NULL
2455 */
2456const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2457 int desc_type)
2458{
2459 int add_sen_len, add_len, desc_len, k;
2460 const u8 * descp;
2461
2462 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2463 return NULL;
2464 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2465 return NULL;
2466 add_sen_len = (add_sen_len < (sb_len - 8)) ?
2467 add_sen_len : (sb_len - 8);
2468 descp = &sense_buffer[8];
2469 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2470 descp += desc_len;
2471 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2472 desc_len = add_len + 2;
2473 if (descp[0] == desc_type)
2474 return descp;
2475 if (add_len < 0) // short descriptor ??
2476 break;
2477 }
2478 return NULL;
2479}
2480EXPORT_SYMBOL(scsi_sense_desc_find);
2481
2482/**
2483 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2484 * @sense_buffer: byte array of sense data
2485 * @sb_len: number of valid bytes in sense_buffer
2486 * @info_out: pointer to 64 integer where 8 or 4 byte information
2487 * field will be placed if found.
2488 *
2489 * Return value:
2490 * 1 if information field found, 0 if not found.
2491 */
2492int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2493 u64 * info_out)
2494{
2495 int j;
2496 const u8 * ucp;
2497 u64 ull;
2498
2499 if (sb_len < 7)
2500 return 0;
2501 switch (sense_buffer[0] & 0x7f) {
2502 case 0x70:
2503 case 0x71:
2504 if (sense_buffer[0] & 0x80) {
2505 *info_out = (sense_buffer[3] << 24) +
2506 (sense_buffer[4] << 16) +
2507 (sense_buffer[5] << 8) + sense_buffer[6];
2508 return 1;
2509 } else
2510 return 0;
2511 case 0x72:
2512 case 0x73:
2513 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2514 0 /* info desc */);
2515 if (ucp && (0xa == ucp[1])) {
2516 ull = 0;
2517 for (j = 0; j < 8; ++j) {
2518 if (j > 0)
2519 ull <<= 8;
2520 ull |= ucp[4 + j];
2521 }
2522 *info_out = ull;
2523 return 1;
2524 } else
2525 return 0;
2526 default:
2527 return 0;
2528 }
2529}
2530EXPORT_SYMBOL(scsi_get_sense_info_fld);
2531
2532/**
2533 * scsi_build_sense_buffer - build sense data in a buffer
2534 * @desc: Sense format (non zero == descriptor format,
2535 * 0 == fixed format)
2536 * @buf: Where to build sense data
2537 * @key: Sense key
2538 * @asc: Additional sense code
2539 * @ascq: Additional sense code qualifier
2540 *
2541 **/
2542void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2543{
2544 if (desc) {
2545 buf[0] = 0x72; /* descriptor, current */
2546 buf[1] = key;
2547 buf[2] = asc;
2548 buf[3] = ascq;
2549 buf[7] = 0;
2550 } else {
2551 buf[0] = 0x70; /* fixed, current */
2552 buf[2] = key;
2553 buf[7] = 0xa;
2554 buf[12] = asc;
2555 buf[13] = ascq;
2556 }
2557}
2558EXPORT_SYMBOL(scsi_build_sense_buffer);