Loading...
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);
1/*
2 * scsi_error.c Copyright (C) 1997 Eric Youngdale
3 *
4 * SCSI error/timeout handling
5 * Initial versions: Eric Youngdale. Based upon conversations with
6 * Leonard Zubkoff and David Miller at Linux Expo,
7 * ideas originating from all over the place.
8 *
9 * Restructured scsi_unjam_host and associated functions.
10 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
11 *
12 * Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
13 * minor cleanups.
14 * September 30, 2002 Mike Anderson (andmike@us.ibm.com)
15 */
16
17#include <linux/module.h>
18#include <linux/sched.h>
19#include <linux/gfp.h>
20#include <linux/timer.h>
21#include <linux/string.h>
22#include <linux/kernel.h>
23#include <linux/freezer.h>
24#include <linux/kthread.h>
25#include <linux/interrupt.h>
26#include <linux/blkdev.h>
27#include <linux/delay.h>
28#include <linux/jiffies.h>
29
30#include <scsi/scsi.h>
31#include <scsi/scsi_cmnd.h>
32#include <scsi/scsi_dbg.h>
33#include <scsi/scsi_device.h>
34#include <scsi/scsi_driver.h>
35#include <scsi/scsi_eh.h>
36#include <scsi/scsi_common.h>
37#include <scsi/scsi_transport.h>
38#include <scsi/scsi_host.h>
39#include <scsi/scsi_ioctl.h>
40#include <scsi/scsi_dh.h>
41#include <scsi/sg.h>
42
43#include "scsi_priv.h"
44#include "scsi_logging.h"
45#include "scsi_transport_api.h"
46
47#include <trace/events/scsi.h>
48
49static void scsi_eh_done(struct scsi_cmnd *scmd);
50
51/*
52 * These should *probably* be handled by the host itself.
53 * Since it is allowed to sleep, it probably should.
54 */
55#define BUS_RESET_SETTLE_TIME (10)
56#define HOST_RESET_SETTLE_TIME (10)
57
58static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
59static int scsi_try_to_abort_cmd(struct scsi_host_template *,
60 struct scsi_cmnd *);
61
62/* called with shost->host_lock held */
63void scsi_eh_wakeup(struct Scsi_Host *shost)
64{
65 if (atomic_read(&shost->host_busy) == shost->host_failed) {
66 trace_scsi_eh_wakeup(shost);
67 wake_up_process(shost->ehandler);
68 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
69 "Waking error handler thread\n"));
70 }
71}
72
73/**
74 * scsi_schedule_eh - schedule EH for SCSI host
75 * @shost: SCSI host to invoke error handling on.
76 *
77 * Schedule SCSI EH without scmd.
78 */
79void scsi_schedule_eh(struct Scsi_Host *shost)
80{
81 unsigned long flags;
82
83 spin_lock_irqsave(shost->host_lock, flags);
84
85 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
86 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
87 shost->host_eh_scheduled++;
88 scsi_eh_wakeup(shost);
89 }
90
91 spin_unlock_irqrestore(shost->host_lock, flags);
92}
93EXPORT_SYMBOL_GPL(scsi_schedule_eh);
94
95static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
96{
97 if (!shost->last_reset || shost->eh_deadline == -1)
98 return 0;
99
100 /*
101 * 32bit accesses are guaranteed to be atomic
102 * (on all supported architectures), so instead
103 * of using a spinlock we can as well double check
104 * if eh_deadline has been set to 'off' during the
105 * time_before call.
106 */
107 if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
108 shost->eh_deadline > -1)
109 return 0;
110
111 return 1;
112}
113
114/**
115 * scmd_eh_abort_handler - Handle command aborts
116 * @work: command to be aborted.
117 */
118void
119scmd_eh_abort_handler(struct work_struct *work)
120{
121 struct scsi_cmnd *scmd =
122 container_of(work, struct scsi_cmnd, abort_work.work);
123 struct scsi_device *sdev = scmd->device;
124 int rtn;
125
126 if (scsi_host_eh_past_deadline(sdev->host)) {
127 SCSI_LOG_ERROR_RECOVERY(3,
128 scmd_printk(KERN_INFO, scmd,
129 "eh timeout, not aborting\n"));
130 } else {
131 SCSI_LOG_ERROR_RECOVERY(3,
132 scmd_printk(KERN_INFO, scmd,
133 "aborting command\n"));
134 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
135 if (rtn == SUCCESS) {
136 set_host_byte(scmd, DID_TIME_OUT);
137 if (scsi_host_eh_past_deadline(sdev->host)) {
138 SCSI_LOG_ERROR_RECOVERY(3,
139 scmd_printk(KERN_INFO, scmd,
140 "eh timeout, not retrying "
141 "aborted command\n"));
142 } else if (!scsi_noretry_cmd(scmd) &&
143 (++scmd->retries <= scmd->allowed)) {
144 SCSI_LOG_ERROR_RECOVERY(3,
145 scmd_printk(KERN_WARNING, scmd,
146 "retry aborted command\n"));
147 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
148 return;
149 } else {
150 SCSI_LOG_ERROR_RECOVERY(3,
151 scmd_printk(KERN_WARNING, scmd,
152 "finish aborted command\n"));
153 scsi_finish_command(scmd);
154 return;
155 }
156 } else {
157 SCSI_LOG_ERROR_RECOVERY(3,
158 scmd_printk(KERN_INFO, scmd,
159 "cmd abort %s\n",
160 (rtn == FAST_IO_FAIL) ?
161 "not send" : "failed"));
162 }
163 }
164
165 if (!scsi_eh_scmd_add(scmd, 0)) {
166 SCSI_LOG_ERROR_RECOVERY(3,
167 scmd_printk(KERN_WARNING, scmd,
168 "terminate aborted command\n"));
169 set_host_byte(scmd, DID_TIME_OUT);
170 scsi_finish_command(scmd);
171 }
172}
173
174/**
175 * scsi_abort_command - schedule a command abort
176 * @scmd: scmd to abort.
177 *
178 * We only need to abort commands after a command timeout
179 */
180static int
181scsi_abort_command(struct scsi_cmnd *scmd)
182{
183 struct scsi_device *sdev = scmd->device;
184 struct Scsi_Host *shost = sdev->host;
185 unsigned long flags;
186
187 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
188 /*
189 * Retry after abort failed, escalate to next level.
190 */
191 scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
192 SCSI_LOG_ERROR_RECOVERY(3,
193 scmd_printk(KERN_INFO, scmd,
194 "previous abort failed\n"));
195 BUG_ON(delayed_work_pending(&scmd->abort_work));
196 return FAILED;
197 }
198
199 /*
200 * Do not try a command abort if
201 * SCSI EH has already started.
202 */
203 spin_lock_irqsave(shost->host_lock, flags);
204 if (scsi_host_in_recovery(shost)) {
205 spin_unlock_irqrestore(shost->host_lock, flags);
206 SCSI_LOG_ERROR_RECOVERY(3,
207 scmd_printk(KERN_INFO, scmd,
208 "not aborting, host in recovery\n"));
209 return FAILED;
210 }
211
212 if (shost->eh_deadline != -1 && !shost->last_reset)
213 shost->last_reset = jiffies;
214 spin_unlock_irqrestore(shost->host_lock, flags);
215
216 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
217 SCSI_LOG_ERROR_RECOVERY(3,
218 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
219 queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
220 return SUCCESS;
221}
222
223/**
224 * scsi_eh_scmd_add - add scsi cmd to error handling.
225 * @scmd: scmd to run eh on.
226 * @eh_flag: optional SCSI_EH flag.
227 *
228 * Return value:
229 * 0 on failure.
230 */
231int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
232{
233 struct Scsi_Host *shost = scmd->device->host;
234 unsigned long flags;
235 int ret = 0;
236
237 if (!shost->ehandler)
238 return 0;
239
240 spin_lock_irqsave(shost->host_lock, flags);
241 if (scsi_host_set_state(shost, SHOST_RECOVERY))
242 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
243 goto out_unlock;
244
245 if (shost->eh_deadline != -1 && !shost->last_reset)
246 shost->last_reset = jiffies;
247
248 ret = 1;
249 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
250 eh_flag &= ~SCSI_EH_CANCEL_CMD;
251 scmd->eh_eflags |= eh_flag;
252 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
253 shost->host_failed++;
254 scsi_eh_wakeup(shost);
255 out_unlock:
256 spin_unlock_irqrestore(shost->host_lock, flags);
257 return ret;
258}
259
260/**
261 * scsi_times_out - Timeout function for normal scsi commands.
262 * @req: request that is timing out.
263 *
264 * Notes:
265 * We do not need to lock this. There is the potential for a race
266 * only in that the normal completion handling might run, but if the
267 * normal completion function determines that the timer has already
268 * fired, then it mustn't do anything.
269 */
270enum blk_eh_timer_return scsi_times_out(struct request *req)
271{
272 struct scsi_cmnd *scmd = req->special;
273 enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
274 struct Scsi_Host *host = scmd->device->host;
275
276 trace_scsi_dispatch_cmd_timeout(scmd);
277 scsi_log_completion(scmd, TIMEOUT_ERROR);
278
279 if (host->eh_deadline != -1 && !host->last_reset)
280 host->last_reset = jiffies;
281
282 if (host->transportt->eh_timed_out)
283 rtn = host->transportt->eh_timed_out(scmd);
284 else if (host->hostt->eh_timed_out)
285 rtn = host->hostt->eh_timed_out(scmd);
286
287 if (rtn == BLK_EH_NOT_HANDLED) {
288 if (!host->hostt->no_async_abort &&
289 scsi_abort_command(scmd) == SUCCESS)
290 return BLK_EH_NOT_HANDLED;
291
292 set_host_byte(scmd, DID_TIME_OUT);
293 if (!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))
294 rtn = BLK_EH_HANDLED;
295 }
296
297 return rtn;
298}
299
300/**
301 * scsi_block_when_processing_errors - Prevent cmds from being queued.
302 * @sdev: Device on which we are performing recovery.
303 *
304 * Description:
305 * We block until the host is out of error recovery, and then check to
306 * see whether the host or the device is offline.
307 *
308 * Return value:
309 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
310 */
311int scsi_block_when_processing_errors(struct scsi_device *sdev)
312{
313 int online;
314
315 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
316
317 online = scsi_device_online(sdev);
318
319 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_INFO, sdev,
320 "%s: rtn: %d\n", __func__, online));
321
322 return online;
323}
324EXPORT_SYMBOL(scsi_block_when_processing_errors);
325
326#ifdef CONFIG_SCSI_LOGGING
327/**
328 * scsi_eh_prt_fail_stats - Log info on failures.
329 * @shost: scsi host being recovered.
330 * @work_q: Queue of scsi cmds to process.
331 */
332static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
333 struct list_head *work_q)
334{
335 struct scsi_cmnd *scmd;
336 struct scsi_device *sdev;
337 int total_failures = 0;
338 int cmd_failed = 0;
339 int cmd_cancel = 0;
340 int devices_failed = 0;
341
342 shost_for_each_device(sdev, shost) {
343 list_for_each_entry(scmd, work_q, eh_entry) {
344 if (scmd->device == sdev) {
345 ++total_failures;
346 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
347 ++cmd_cancel;
348 else
349 ++cmd_failed;
350 }
351 }
352
353 if (cmd_cancel || cmd_failed) {
354 SCSI_LOG_ERROR_RECOVERY(3,
355 shost_printk(KERN_INFO, shost,
356 "%s: cmds failed: %d, cancel: %d\n",
357 __func__, cmd_failed,
358 cmd_cancel));
359 cmd_cancel = 0;
360 cmd_failed = 0;
361 ++devices_failed;
362 }
363 }
364
365 SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
366 "Total of %d commands on %d"
367 " devices require eh work\n",
368 total_failures, devices_failed));
369}
370#endif
371
372 /**
373 * scsi_report_lun_change - Set flag on all *other* devices on the same target
374 * to indicate that a UNIT ATTENTION is expected.
375 * @sdev: Device reporting the UNIT ATTENTION
376 */
377static void scsi_report_lun_change(struct scsi_device *sdev)
378{
379 sdev->sdev_target->expecting_lun_change = 1;
380}
381
382/**
383 * scsi_report_sense - Examine scsi sense information and log messages for
384 * certain conditions, also issue uevents for some of them.
385 * @sdev: Device reporting the sense code
386 * @sshdr: sshdr to be examined
387 */
388static void scsi_report_sense(struct scsi_device *sdev,
389 struct scsi_sense_hdr *sshdr)
390{
391 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
392
393 if (sshdr->sense_key == UNIT_ATTENTION) {
394 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
395 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
396 sdev_printk(KERN_WARNING, sdev,
397 "Inquiry data has changed");
398 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
399 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
400 scsi_report_lun_change(sdev);
401 sdev_printk(KERN_WARNING, sdev,
402 "Warning! Received an indication that the "
403 "LUN assignments on this target have "
404 "changed. The Linux SCSI layer does not "
405 "automatically remap LUN assignments.\n");
406 } else if (sshdr->asc == 0x3f)
407 sdev_printk(KERN_WARNING, sdev,
408 "Warning! Received an indication that the "
409 "operating parameters on this target have "
410 "changed. The Linux SCSI layer does not "
411 "automatically adjust these parameters.\n");
412
413 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
414 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
415 sdev_printk(KERN_WARNING, sdev,
416 "Warning! Received an indication that the "
417 "LUN reached a thin provisioning soft "
418 "threshold.\n");
419 }
420
421 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
422 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
423 sdev_printk(KERN_WARNING, sdev,
424 "Mode parameters changed");
425 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
426 evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
427 sdev_printk(KERN_WARNING, sdev,
428 "Asymmetric access state changed");
429 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
430 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
431 sdev_printk(KERN_WARNING, sdev,
432 "Capacity data has changed");
433 } else if (sshdr->asc == 0x2a)
434 sdev_printk(KERN_WARNING, sdev,
435 "Parameters changed");
436 }
437
438 if (evt_type != SDEV_EVT_MAXBITS) {
439 set_bit(evt_type, sdev->pending_events);
440 schedule_work(&sdev->event_work);
441 }
442}
443
444/**
445 * scsi_check_sense - Examine scsi cmd sense
446 * @scmd: Cmd to have sense checked.
447 *
448 * Return value:
449 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
450 *
451 * Notes:
452 * When a deferred error is detected the current command has
453 * not been executed and needs retrying.
454 */
455int scsi_check_sense(struct scsi_cmnd *scmd)
456{
457 struct scsi_device *sdev = scmd->device;
458 struct scsi_sense_hdr sshdr;
459
460 if (! scsi_command_normalize_sense(scmd, &sshdr))
461 return FAILED; /* no valid sense data */
462
463 scsi_report_sense(sdev, &sshdr);
464
465 if (scsi_sense_is_deferred(&sshdr))
466 return NEEDS_RETRY;
467
468 if (sdev->handler && sdev->handler->check_sense) {
469 int rc;
470
471 rc = sdev->handler->check_sense(sdev, &sshdr);
472 if (rc != SCSI_RETURN_NOT_HANDLED)
473 return rc;
474 /* handler does not care. Drop down to default handling */
475 }
476
477 if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
478 /*
479 * nasty: for mid-layer issued TURs, we need to return the
480 * actual sense data without any recovery attempt. For eh
481 * issued ones, we need to try to recover and interpret
482 */
483 return SUCCESS;
484
485 /*
486 * Previous logic looked for FILEMARK, EOM or ILI which are
487 * mainly associated with tapes and returned SUCCESS.
488 */
489 if (sshdr.response_code == 0x70) {
490 /* fixed format */
491 if (scmd->sense_buffer[2] & 0xe0)
492 return SUCCESS;
493 } else {
494 /*
495 * descriptor format: look for "stream commands sense data
496 * descriptor" (see SSC-3). Assume single sense data
497 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
498 */
499 if ((sshdr.additional_length > 3) &&
500 (scmd->sense_buffer[8] == 0x4) &&
501 (scmd->sense_buffer[11] & 0xe0))
502 return SUCCESS;
503 }
504
505 switch (sshdr.sense_key) {
506 case NO_SENSE:
507 return SUCCESS;
508 case RECOVERED_ERROR:
509 return /* soft_error */ SUCCESS;
510
511 case ABORTED_COMMAND:
512 if (sshdr.asc == 0x10) /* DIF */
513 return SUCCESS;
514
515 return NEEDS_RETRY;
516 case NOT_READY:
517 case UNIT_ATTENTION:
518 /*
519 * if we are expecting a cc/ua because of a bus reset that we
520 * performed, treat this just as a retry. otherwise this is
521 * information that we should pass up to the upper-level driver
522 * so that we can deal with it there.
523 */
524 if (scmd->device->expecting_cc_ua) {
525 /*
526 * Because some device does not queue unit
527 * attentions correctly, we carefully check
528 * additional sense code and qualifier so as
529 * not to squash media change unit attention.
530 */
531 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
532 scmd->device->expecting_cc_ua = 0;
533 return NEEDS_RETRY;
534 }
535 }
536 /*
537 * we might also expect a cc/ua if another LUN on the target
538 * reported a UA with an ASC/ASCQ of 3F 0E -
539 * REPORTED LUNS DATA HAS CHANGED.
540 */
541 if (scmd->device->sdev_target->expecting_lun_change &&
542 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
543 return NEEDS_RETRY;
544 /*
545 * if the device is in the process of becoming ready, we
546 * should retry.
547 */
548 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
549 return NEEDS_RETRY;
550 /*
551 * if the device is not started, we need to wake
552 * the error handler to start the motor
553 */
554 if (scmd->device->allow_restart &&
555 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
556 return FAILED;
557 /*
558 * Pass the UA upwards for a determination in the completion
559 * functions.
560 */
561 return SUCCESS;
562
563 /* these are not supported */
564 case DATA_PROTECT:
565 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
566 /* Thin provisioning hard threshold reached */
567 set_host_byte(scmd, DID_ALLOC_FAILURE);
568 return SUCCESS;
569 }
570 case COPY_ABORTED:
571 case VOLUME_OVERFLOW:
572 case MISCOMPARE:
573 case BLANK_CHECK:
574 set_host_byte(scmd, DID_TARGET_FAILURE);
575 return SUCCESS;
576
577 case MEDIUM_ERROR:
578 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
579 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
580 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
581 set_host_byte(scmd, DID_MEDIUM_ERROR);
582 return SUCCESS;
583 }
584 return NEEDS_RETRY;
585
586 case HARDWARE_ERROR:
587 if (scmd->device->retry_hwerror)
588 return ADD_TO_MLQUEUE;
589 else
590 set_host_byte(scmd, DID_TARGET_FAILURE);
591
592 case ILLEGAL_REQUEST:
593 if (sshdr.asc == 0x20 || /* Invalid command operation code */
594 sshdr.asc == 0x21 || /* Logical block address out of range */
595 sshdr.asc == 0x24 || /* Invalid field in cdb */
596 sshdr.asc == 0x26) { /* Parameter value invalid */
597 set_host_byte(scmd, DID_TARGET_FAILURE);
598 }
599 return SUCCESS;
600
601 default:
602 return SUCCESS;
603 }
604}
605EXPORT_SYMBOL_GPL(scsi_check_sense);
606
607static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
608{
609 struct scsi_host_template *sht = sdev->host->hostt;
610 struct scsi_device *tmp_sdev;
611
612 if (!sht->track_queue_depth ||
613 sdev->queue_depth >= sdev->max_queue_depth)
614 return;
615
616 if (time_before(jiffies,
617 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
618 return;
619
620 if (time_before(jiffies,
621 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
622 return;
623
624 /*
625 * Walk all devices of a target and do
626 * ramp up on them.
627 */
628 shost_for_each_device(tmp_sdev, sdev->host) {
629 if (tmp_sdev->channel != sdev->channel ||
630 tmp_sdev->id != sdev->id ||
631 tmp_sdev->queue_depth == sdev->max_queue_depth)
632 continue;
633
634 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
635 sdev->last_queue_ramp_up = jiffies;
636 }
637}
638
639static void scsi_handle_queue_full(struct scsi_device *sdev)
640{
641 struct scsi_host_template *sht = sdev->host->hostt;
642 struct scsi_device *tmp_sdev;
643
644 if (!sht->track_queue_depth)
645 return;
646
647 shost_for_each_device(tmp_sdev, sdev->host) {
648 if (tmp_sdev->channel != sdev->channel ||
649 tmp_sdev->id != sdev->id)
650 continue;
651 /*
652 * We do not know the number of commands that were at
653 * the device when we got the queue full so we start
654 * from the highest possible value and work our way down.
655 */
656 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
657 }
658}
659
660/**
661 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
662 * @scmd: SCSI cmd to examine.
663 *
664 * Notes:
665 * This is *only* called when we are examining the status of commands
666 * queued during error recovery. the main difference here is that we
667 * don't allow for the possibility of retries here, and we are a lot
668 * more restrictive about what we consider acceptable.
669 */
670static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
671{
672 /*
673 * first check the host byte, to see if there is anything in there
674 * that would indicate what we need to do.
675 */
676 if (host_byte(scmd->result) == DID_RESET) {
677 /*
678 * rats. we are already in the error handler, so we now
679 * get to try and figure out what to do next. if the sense
680 * is valid, we have a pretty good idea of what to do.
681 * if not, we mark it as FAILED.
682 */
683 return scsi_check_sense(scmd);
684 }
685 if (host_byte(scmd->result) != DID_OK)
686 return FAILED;
687
688 /*
689 * next, check the message byte.
690 */
691 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
692 return FAILED;
693
694 /*
695 * now, check the status byte to see if this indicates
696 * anything special.
697 */
698 switch (status_byte(scmd->result)) {
699 case GOOD:
700 scsi_handle_queue_ramp_up(scmd->device);
701 case COMMAND_TERMINATED:
702 return SUCCESS;
703 case CHECK_CONDITION:
704 return scsi_check_sense(scmd);
705 case CONDITION_GOOD:
706 case INTERMEDIATE_GOOD:
707 case INTERMEDIATE_C_GOOD:
708 /*
709 * who knows? FIXME(eric)
710 */
711 return SUCCESS;
712 case RESERVATION_CONFLICT:
713 if (scmd->cmnd[0] == TEST_UNIT_READY)
714 /* it is a success, we probed the device and
715 * found it */
716 return SUCCESS;
717 /* otherwise, we failed to send the command */
718 return FAILED;
719 case QUEUE_FULL:
720 scsi_handle_queue_full(scmd->device);
721 /* fall through */
722 case BUSY:
723 return NEEDS_RETRY;
724 default:
725 return FAILED;
726 }
727 return FAILED;
728}
729
730/**
731 * scsi_eh_done - Completion function for error handling.
732 * @scmd: Cmd that is done.
733 */
734static void scsi_eh_done(struct scsi_cmnd *scmd)
735{
736 struct completion *eh_action;
737
738 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
739 "%s result: %x\n", __func__, scmd->result));
740
741 eh_action = scmd->device->host->eh_action;
742 if (eh_action)
743 complete(eh_action);
744}
745
746/**
747 * scsi_try_host_reset - ask host adapter to reset itself
748 * @scmd: SCSI cmd to send host reset.
749 */
750static int scsi_try_host_reset(struct scsi_cmnd *scmd)
751{
752 unsigned long flags;
753 int rtn;
754 struct Scsi_Host *host = scmd->device->host;
755 struct scsi_host_template *hostt = host->hostt;
756
757 SCSI_LOG_ERROR_RECOVERY(3,
758 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
759
760 if (!hostt->eh_host_reset_handler)
761 return FAILED;
762
763 rtn = hostt->eh_host_reset_handler(scmd);
764
765 if (rtn == SUCCESS) {
766 if (!hostt->skip_settle_delay)
767 ssleep(HOST_RESET_SETTLE_TIME);
768 spin_lock_irqsave(host->host_lock, flags);
769 scsi_report_bus_reset(host, scmd_channel(scmd));
770 spin_unlock_irqrestore(host->host_lock, flags);
771 }
772
773 return rtn;
774}
775
776/**
777 * scsi_try_bus_reset - ask host to perform a bus reset
778 * @scmd: SCSI cmd to send bus reset.
779 */
780static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
781{
782 unsigned long flags;
783 int rtn;
784 struct Scsi_Host *host = scmd->device->host;
785 struct scsi_host_template *hostt = host->hostt;
786
787 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
788 "%s: Snd Bus RST\n", __func__));
789
790 if (!hostt->eh_bus_reset_handler)
791 return FAILED;
792
793 rtn = hostt->eh_bus_reset_handler(scmd);
794
795 if (rtn == SUCCESS) {
796 if (!hostt->skip_settle_delay)
797 ssleep(BUS_RESET_SETTLE_TIME);
798 spin_lock_irqsave(host->host_lock, flags);
799 scsi_report_bus_reset(host, scmd_channel(scmd));
800 spin_unlock_irqrestore(host->host_lock, flags);
801 }
802
803 return rtn;
804}
805
806static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
807{
808 sdev->was_reset = 1;
809 sdev->expecting_cc_ua = 1;
810}
811
812/**
813 * scsi_try_target_reset - Ask host to perform a target reset
814 * @scmd: SCSI cmd used to send a target reset
815 *
816 * Notes:
817 * There is no timeout for this operation. if this operation is
818 * unreliable for a given host, then the host itself needs to put a
819 * timer on it, and set the host back to a consistent state prior to
820 * returning.
821 */
822static int scsi_try_target_reset(struct scsi_cmnd *scmd)
823{
824 unsigned long flags;
825 int rtn;
826 struct Scsi_Host *host = scmd->device->host;
827 struct scsi_host_template *hostt = host->hostt;
828
829 if (!hostt->eh_target_reset_handler)
830 return FAILED;
831
832 rtn = hostt->eh_target_reset_handler(scmd);
833 if (rtn == SUCCESS) {
834 spin_lock_irqsave(host->host_lock, flags);
835 __starget_for_each_device(scsi_target(scmd->device), NULL,
836 __scsi_report_device_reset);
837 spin_unlock_irqrestore(host->host_lock, flags);
838 }
839
840 return rtn;
841}
842
843/**
844 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
845 * @scmd: SCSI cmd used to send BDR
846 *
847 * Notes:
848 * There is no timeout for this operation. if this operation is
849 * unreliable for a given host, then the host itself needs to put a
850 * timer on it, and set the host back to a consistent state prior to
851 * returning.
852 */
853static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
854{
855 int rtn;
856 struct scsi_host_template *hostt = scmd->device->host->hostt;
857
858 if (!hostt->eh_device_reset_handler)
859 return FAILED;
860
861 rtn = hostt->eh_device_reset_handler(scmd);
862 if (rtn == SUCCESS)
863 __scsi_report_device_reset(scmd->device, NULL);
864 return rtn;
865}
866
867/**
868 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
869 * @hostt: SCSI driver host template
870 * @scmd: SCSI cmd used to send a target reset
871 *
872 * Return value:
873 * SUCCESS, FAILED, or FAST_IO_FAIL
874 *
875 * Notes:
876 * SUCCESS does not necessarily indicate that the command
877 * has been aborted; it only indicates that the LLDDs
878 * has cleared all references to that command.
879 * LLDDs should return FAILED only if an abort was required
880 * but could not be executed. LLDDs should return FAST_IO_FAIL
881 * if the device is temporarily unavailable (eg due to a
882 * link down on FibreChannel)
883 */
884static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt,
885 struct scsi_cmnd *scmd)
886{
887 if (!hostt->eh_abort_handler)
888 return FAILED;
889
890 return hostt->eh_abort_handler(scmd);
891}
892
893static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
894{
895 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
896 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
897 if (scsi_try_target_reset(scmd) != SUCCESS)
898 if (scsi_try_bus_reset(scmd) != SUCCESS)
899 scsi_try_host_reset(scmd);
900}
901
902/**
903 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
904 * @scmd: SCSI command structure to hijack
905 * @ses: structure to save restore information
906 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
907 * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
908 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
909 *
910 * This function is used to save a scsi command information before re-execution
911 * as part of the error recovery process. If @sense_bytes is 0 the command
912 * sent must be one that does not transfer any data. If @sense_bytes != 0
913 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
914 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
915 */
916void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
917 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
918{
919 struct scsi_device *sdev = scmd->device;
920
921 /*
922 * We need saved copies of a number of fields - this is because
923 * error handling may need to overwrite these with different values
924 * to run different commands, and once error handling is complete,
925 * we will need to restore these values prior to running the actual
926 * command.
927 */
928 ses->cmd_len = scmd->cmd_len;
929 ses->cmnd = scmd->cmnd;
930 ses->data_direction = scmd->sc_data_direction;
931 ses->sdb = scmd->sdb;
932 ses->next_rq = scmd->request->next_rq;
933 ses->result = scmd->result;
934 ses->underflow = scmd->underflow;
935 ses->prot_op = scmd->prot_op;
936
937 scmd->prot_op = SCSI_PROT_NORMAL;
938 scmd->eh_eflags = 0;
939 scmd->cmnd = ses->eh_cmnd;
940 memset(scmd->cmnd, 0, BLK_MAX_CDB);
941 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
942 scmd->request->next_rq = NULL;
943 scmd->result = 0;
944
945 if (sense_bytes) {
946 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
947 sense_bytes);
948 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
949 scmd->sdb.length);
950 scmd->sdb.table.sgl = &ses->sense_sgl;
951 scmd->sc_data_direction = DMA_FROM_DEVICE;
952 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
953 scmd->cmnd[0] = REQUEST_SENSE;
954 scmd->cmnd[4] = scmd->sdb.length;
955 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
956 } else {
957 scmd->sc_data_direction = DMA_NONE;
958 if (cmnd) {
959 BUG_ON(cmnd_size > BLK_MAX_CDB);
960 memcpy(scmd->cmnd, cmnd, cmnd_size);
961 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
962 }
963 }
964
965 scmd->underflow = 0;
966
967 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
968 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
969 (sdev->lun << 5 & 0xe0);
970
971 /*
972 * Zero the sense buffer. The scsi spec mandates that any
973 * untransferred sense data should be interpreted as being zero.
974 */
975 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
976}
977EXPORT_SYMBOL(scsi_eh_prep_cmnd);
978
979/**
980 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
981 * @scmd: SCSI command structure to restore
982 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
983 *
984 * Undo any damage done by above scsi_eh_prep_cmnd().
985 */
986void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
987{
988 /*
989 * Restore original data
990 */
991 scmd->cmd_len = ses->cmd_len;
992 scmd->cmnd = ses->cmnd;
993 scmd->sc_data_direction = ses->data_direction;
994 scmd->sdb = ses->sdb;
995 scmd->request->next_rq = ses->next_rq;
996 scmd->result = ses->result;
997 scmd->underflow = ses->underflow;
998 scmd->prot_op = ses->prot_op;
999}
1000EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1001
1002/**
1003 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1004 * @scmd: SCSI command structure to hijack
1005 * @cmnd: CDB to send
1006 * @cmnd_size: size in bytes of @cmnd
1007 * @timeout: timeout for this request
1008 * @sense_bytes: size of sense data to copy or 0
1009 *
1010 * This function is used to send a scsi command down to a target device
1011 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1012 *
1013 * Return value:
1014 * SUCCESS or FAILED or NEEDS_RETRY
1015 */
1016static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
1017 int cmnd_size, int timeout, unsigned sense_bytes)
1018{
1019 struct scsi_device *sdev = scmd->device;
1020 struct Scsi_Host *shost = sdev->host;
1021 DECLARE_COMPLETION_ONSTACK(done);
1022 unsigned long timeleft = timeout;
1023 struct scsi_eh_save ses;
1024 const unsigned long stall_for = msecs_to_jiffies(100);
1025 int rtn;
1026
1027retry:
1028 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1029 shost->eh_action = &done;
1030
1031 scsi_log_send(scmd);
1032 scmd->scsi_done = scsi_eh_done;
1033 rtn = shost->hostt->queuecommand(shost, scmd);
1034 if (rtn) {
1035 if (timeleft > stall_for) {
1036 scsi_eh_restore_cmnd(scmd, &ses);
1037 timeleft -= stall_for;
1038 msleep(jiffies_to_msecs(stall_for));
1039 goto retry;
1040 }
1041 /* signal not to enter either branch of the if () below */
1042 timeleft = 0;
1043 rtn = FAILED;
1044 } else {
1045 timeleft = wait_for_completion_timeout(&done, timeout);
1046 rtn = SUCCESS;
1047 }
1048
1049 shost->eh_action = NULL;
1050
1051 scsi_log_completion(scmd, rtn);
1052
1053 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1054 "%s timeleft: %ld\n",
1055 __func__, timeleft));
1056
1057 /*
1058 * If there is time left scsi_eh_done got called, and we will examine
1059 * the actual status codes to see whether the command actually did
1060 * complete normally, else if we have a zero return and no time left,
1061 * the command must still be pending, so abort it and return FAILED.
1062 * If we never actually managed to issue the command, because
1063 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1064 * value above (so don't execute either branch of the if)
1065 */
1066 if (timeleft) {
1067 rtn = scsi_eh_completed_normally(scmd);
1068 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1069 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1070
1071 switch (rtn) {
1072 case SUCCESS:
1073 case NEEDS_RETRY:
1074 case FAILED:
1075 break;
1076 case ADD_TO_MLQUEUE:
1077 rtn = NEEDS_RETRY;
1078 break;
1079 default:
1080 rtn = FAILED;
1081 break;
1082 }
1083 } else if (rtn != FAILED) {
1084 scsi_abort_eh_cmnd(scmd);
1085 rtn = FAILED;
1086 }
1087
1088 scsi_eh_restore_cmnd(scmd, &ses);
1089
1090 return rtn;
1091}
1092
1093/**
1094 * scsi_request_sense - Request sense data from a particular target.
1095 * @scmd: SCSI cmd for request sense.
1096 *
1097 * Notes:
1098 * Some hosts automatically obtain this information, others require
1099 * that we obtain it on our own. This function will *not* return until
1100 * the command either times out, or it completes.
1101 */
1102static int scsi_request_sense(struct scsi_cmnd *scmd)
1103{
1104 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1105}
1106
1107static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
1108{
1109 if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
1110 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1111 if (sdrv->eh_action)
1112 rtn = sdrv->eh_action(scmd, rtn);
1113 }
1114 return rtn;
1115}
1116
1117/**
1118 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1119 * @scmd: Original SCSI cmd that eh has finished.
1120 * @done_q: Queue for processed commands.
1121 *
1122 * Notes:
1123 * We don't want to use the normal command completion while we are are
1124 * still handling errors - it may cause other commands to be queued,
1125 * and that would disturb what we are doing. Thus we really want to
1126 * keep a list of pending commands for final completion, and once we
1127 * are ready to leave error handling we handle completion for real.
1128 */
1129void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1130{
1131 scmd->eh_eflags = 0;
1132 list_move_tail(&scmd->eh_entry, done_q);
1133}
1134EXPORT_SYMBOL(scsi_eh_finish_cmd);
1135
1136/**
1137 * scsi_eh_get_sense - Get device sense data.
1138 * @work_q: Queue of commands to process.
1139 * @done_q: Queue of processed commands.
1140 *
1141 * Description:
1142 * See if we need to request sense information. if so, then get it
1143 * now, so we have a better idea of what to do.
1144 *
1145 * Notes:
1146 * This has the unfortunate side effect that if a shost adapter does
1147 * not automatically request sense information, we end up shutting
1148 * it down before we request it.
1149 *
1150 * All drivers should request sense information internally these days,
1151 * so for now all I have to say is tough noogies if you end up in here.
1152 *
1153 * XXX: Long term this code should go away, but that needs an audit of
1154 * all LLDDs first.
1155 */
1156int scsi_eh_get_sense(struct list_head *work_q,
1157 struct list_head *done_q)
1158{
1159 struct scsi_cmnd *scmd, *next;
1160 struct Scsi_Host *shost;
1161 int rtn;
1162
1163 /*
1164 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1165 * should not get sense.
1166 */
1167 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1168 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
1169 (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1170 SCSI_SENSE_VALID(scmd))
1171 continue;
1172
1173 shost = scmd->device->host;
1174 if (scsi_host_eh_past_deadline(shost)) {
1175 SCSI_LOG_ERROR_RECOVERY(3,
1176 scmd_printk(KERN_INFO, scmd,
1177 "%s: skip request sense, past eh deadline\n",
1178 current->comm));
1179 break;
1180 }
1181 if (status_byte(scmd->result) != CHECK_CONDITION)
1182 /*
1183 * don't request sense if there's no check condition
1184 * status because the error we're processing isn't one
1185 * that has a sense code (and some devices get
1186 * confused by sense requests out of the blue)
1187 */
1188 continue;
1189
1190 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1191 "%s: requesting sense\n",
1192 current->comm));
1193 rtn = scsi_request_sense(scmd);
1194 if (rtn != SUCCESS)
1195 continue;
1196
1197 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1198 "sense requested, result %x\n", scmd->result));
1199 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1200
1201 rtn = scsi_decide_disposition(scmd);
1202
1203 /*
1204 * if the result was normal, then just pass it along to the
1205 * upper level.
1206 */
1207 if (rtn == SUCCESS)
1208 /* we don't want this command reissued, just
1209 * finished with the sense data, so set
1210 * retries to the max allowed to ensure it
1211 * won't get reissued */
1212 scmd->retries = scmd->allowed;
1213 else if (rtn != NEEDS_RETRY)
1214 continue;
1215
1216 scsi_eh_finish_cmd(scmd, done_q);
1217 }
1218
1219 return list_empty(work_q);
1220}
1221EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1222
1223/**
1224 * scsi_eh_tur - Send TUR to device.
1225 * @scmd: &scsi_cmnd to send TUR
1226 *
1227 * Return value:
1228 * 0 - Device is ready. 1 - Device NOT ready.
1229 */
1230static int scsi_eh_tur(struct scsi_cmnd *scmd)
1231{
1232 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1233 int retry_cnt = 1, rtn;
1234
1235retry_tur:
1236 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1237 scmd->device->eh_timeout, 0);
1238
1239 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1240 "%s return: %x\n", __func__, rtn));
1241
1242 switch (rtn) {
1243 case NEEDS_RETRY:
1244 if (retry_cnt--)
1245 goto retry_tur;
1246 /*FALLTHRU*/
1247 case SUCCESS:
1248 return 0;
1249 default:
1250 return 1;
1251 }
1252}
1253
1254/**
1255 * scsi_eh_test_devices - check if devices are responding from error recovery.
1256 * @cmd_list: scsi commands in error recovery.
1257 * @work_q: queue for commands which still need more error recovery
1258 * @done_q: queue for commands which are finished
1259 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1260 *
1261 * Decription:
1262 * Tests if devices are in a working state. Commands to devices now in
1263 * a working state are sent to the done_q while commands to devices which
1264 * are still failing to respond are returned to the work_q for more
1265 * processing.
1266 **/
1267static int scsi_eh_test_devices(struct list_head *cmd_list,
1268 struct list_head *work_q,
1269 struct list_head *done_q, int try_stu)
1270{
1271 struct scsi_cmnd *scmd, *next;
1272 struct scsi_device *sdev;
1273 int finish_cmds;
1274
1275 while (!list_empty(cmd_list)) {
1276 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1277 sdev = scmd->device;
1278
1279 if (!try_stu) {
1280 if (scsi_host_eh_past_deadline(sdev->host)) {
1281 /* Push items back onto work_q */
1282 list_splice_init(cmd_list, work_q);
1283 SCSI_LOG_ERROR_RECOVERY(3,
1284 sdev_printk(KERN_INFO, sdev,
1285 "%s: skip test device, past eh deadline",
1286 current->comm));
1287 break;
1288 }
1289 }
1290
1291 finish_cmds = !scsi_device_online(scmd->device) ||
1292 (try_stu && !scsi_eh_try_stu(scmd) &&
1293 !scsi_eh_tur(scmd)) ||
1294 !scsi_eh_tur(scmd);
1295
1296 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1297 if (scmd->device == sdev) {
1298 if (finish_cmds &&
1299 (try_stu ||
1300 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1301 scsi_eh_finish_cmd(scmd, done_q);
1302 else
1303 list_move_tail(&scmd->eh_entry, work_q);
1304 }
1305 }
1306 return list_empty(work_q);
1307}
1308
1309
1310/**
1311 * scsi_eh_abort_cmds - abort pending commands.
1312 * @work_q: &list_head for pending commands.
1313 * @done_q: &list_head for processed commands.
1314 *
1315 * Decription:
1316 * Try and see whether or not it makes sense to try and abort the
1317 * running command. This only works out to be the case if we have one
1318 * command that has timed out. If the command simply failed, it makes
1319 * no sense to try and abort the command, since as far as the shost
1320 * adapter is concerned, it isn't running.
1321 */
1322static int scsi_eh_abort_cmds(struct list_head *work_q,
1323 struct list_head *done_q)
1324{
1325 struct scsi_cmnd *scmd, *next;
1326 LIST_HEAD(check_list);
1327 int rtn;
1328 struct Scsi_Host *shost;
1329
1330 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1331 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1332 continue;
1333 shost = scmd->device->host;
1334 if (scsi_host_eh_past_deadline(shost)) {
1335 list_splice_init(&check_list, work_q);
1336 SCSI_LOG_ERROR_RECOVERY(3,
1337 scmd_printk(KERN_INFO, scmd,
1338 "%s: skip aborting cmd, past eh deadline\n",
1339 current->comm));
1340 return list_empty(work_q);
1341 }
1342 SCSI_LOG_ERROR_RECOVERY(3,
1343 scmd_printk(KERN_INFO, scmd,
1344 "%s: aborting cmd\n", current->comm));
1345 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1346 if (rtn == FAILED) {
1347 SCSI_LOG_ERROR_RECOVERY(3,
1348 scmd_printk(KERN_INFO, scmd,
1349 "%s: aborting cmd failed\n",
1350 current->comm));
1351 list_splice_init(&check_list, work_q);
1352 return list_empty(work_q);
1353 }
1354 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1355 if (rtn == FAST_IO_FAIL)
1356 scsi_eh_finish_cmd(scmd, done_q);
1357 else
1358 list_move_tail(&scmd->eh_entry, &check_list);
1359 }
1360
1361 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1362}
1363
1364/**
1365 * scsi_eh_try_stu - Send START_UNIT to device.
1366 * @scmd: &scsi_cmnd to send START_UNIT
1367 *
1368 * Return value:
1369 * 0 - Device is ready. 1 - Device NOT ready.
1370 */
1371static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1372{
1373 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1374
1375 if (scmd->device->allow_restart) {
1376 int i, rtn = NEEDS_RETRY;
1377
1378 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1379 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1380
1381 if (rtn == SUCCESS)
1382 return 0;
1383 }
1384
1385 return 1;
1386}
1387
1388 /**
1389 * scsi_eh_stu - send START_UNIT if needed
1390 * @shost: &scsi host being recovered.
1391 * @work_q: &list_head for pending commands.
1392 * @done_q: &list_head for processed commands.
1393 *
1394 * Notes:
1395 * If commands are failing due to not ready, initializing command required,
1396 * try revalidating the device, which will end up sending a start unit.
1397 */
1398static int scsi_eh_stu(struct Scsi_Host *shost,
1399 struct list_head *work_q,
1400 struct list_head *done_q)
1401{
1402 struct scsi_cmnd *scmd, *stu_scmd, *next;
1403 struct scsi_device *sdev;
1404
1405 shost_for_each_device(sdev, shost) {
1406 if (scsi_host_eh_past_deadline(shost)) {
1407 SCSI_LOG_ERROR_RECOVERY(3,
1408 sdev_printk(KERN_INFO, sdev,
1409 "%s: skip START_UNIT, past eh deadline\n",
1410 current->comm));
1411 break;
1412 }
1413 stu_scmd = NULL;
1414 list_for_each_entry(scmd, work_q, eh_entry)
1415 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1416 scsi_check_sense(scmd) == FAILED ) {
1417 stu_scmd = scmd;
1418 break;
1419 }
1420
1421 if (!stu_scmd)
1422 continue;
1423
1424 SCSI_LOG_ERROR_RECOVERY(3,
1425 sdev_printk(KERN_INFO, sdev,
1426 "%s: Sending START_UNIT\n",
1427 current->comm));
1428
1429 if (!scsi_eh_try_stu(stu_scmd)) {
1430 if (!scsi_device_online(sdev) ||
1431 !scsi_eh_tur(stu_scmd)) {
1432 list_for_each_entry_safe(scmd, next,
1433 work_q, eh_entry) {
1434 if (scmd->device == sdev &&
1435 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1436 scsi_eh_finish_cmd(scmd, done_q);
1437 }
1438 }
1439 } else {
1440 SCSI_LOG_ERROR_RECOVERY(3,
1441 sdev_printk(KERN_INFO, sdev,
1442 "%s: START_UNIT failed\n",
1443 current->comm));
1444 }
1445 }
1446
1447 return list_empty(work_q);
1448}
1449
1450
1451/**
1452 * scsi_eh_bus_device_reset - send bdr if needed
1453 * @shost: scsi host being recovered.
1454 * @work_q: &list_head for pending commands.
1455 * @done_q: &list_head for processed commands.
1456 *
1457 * Notes:
1458 * Try a bus device reset. Still, look to see whether we have multiple
1459 * devices that are jammed or not - if we have multiple devices, it
1460 * makes no sense to try bus_device_reset - we really would need to try
1461 * a bus_reset instead.
1462 */
1463static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1464 struct list_head *work_q,
1465 struct list_head *done_q)
1466{
1467 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1468 struct scsi_device *sdev;
1469 int rtn;
1470
1471 shost_for_each_device(sdev, shost) {
1472 if (scsi_host_eh_past_deadline(shost)) {
1473 SCSI_LOG_ERROR_RECOVERY(3,
1474 sdev_printk(KERN_INFO, sdev,
1475 "%s: skip BDR, past eh deadline\n",
1476 current->comm));
1477 break;
1478 }
1479 bdr_scmd = NULL;
1480 list_for_each_entry(scmd, work_q, eh_entry)
1481 if (scmd->device == sdev) {
1482 bdr_scmd = scmd;
1483 break;
1484 }
1485
1486 if (!bdr_scmd)
1487 continue;
1488
1489 SCSI_LOG_ERROR_RECOVERY(3,
1490 sdev_printk(KERN_INFO, sdev,
1491 "%s: Sending BDR\n", current->comm));
1492 rtn = scsi_try_bus_device_reset(bdr_scmd);
1493 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1494 if (!scsi_device_online(sdev) ||
1495 rtn == FAST_IO_FAIL ||
1496 !scsi_eh_tur(bdr_scmd)) {
1497 list_for_each_entry_safe(scmd, next,
1498 work_q, eh_entry) {
1499 if (scmd->device == sdev &&
1500 scsi_eh_action(scmd, rtn) != FAILED)
1501 scsi_eh_finish_cmd(scmd,
1502 done_q);
1503 }
1504 }
1505 } else {
1506 SCSI_LOG_ERROR_RECOVERY(3,
1507 sdev_printk(KERN_INFO, sdev,
1508 "%s: BDR failed\n", current->comm));
1509 }
1510 }
1511
1512 return list_empty(work_q);
1513}
1514
1515/**
1516 * scsi_eh_target_reset - send target reset if needed
1517 * @shost: scsi host being recovered.
1518 * @work_q: &list_head for pending commands.
1519 * @done_q: &list_head for processed commands.
1520 *
1521 * Notes:
1522 * Try a target reset.
1523 */
1524static int scsi_eh_target_reset(struct Scsi_Host *shost,
1525 struct list_head *work_q,
1526 struct list_head *done_q)
1527{
1528 LIST_HEAD(tmp_list);
1529 LIST_HEAD(check_list);
1530
1531 list_splice_init(work_q, &tmp_list);
1532
1533 while (!list_empty(&tmp_list)) {
1534 struct scsi_cmnd *next, *scmd;
1535 int rtn;
1536 unsigned int id;
1537
1538 if (scsi_host_eh_past_deadline(shost)) {
1539 /* push back on work queue for further processing */
1540 list_splice_init(&check_list, work_q);
1541 list_splice_init(&tmp_list, work_q);
1542 SCSI_LOG_ERROR_RECOVERY(3,
1543 shost_printk(KERN_INFO, shost,
1544 "%s: Skip target reset, past eh deadline\n",
1545 current->comm));
1546 return list_empty(work_q);
1547 }
1548
1549 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1550 id = scmd_id(scmd);
1551
1552 SCSI_LOG_ERROR_RECOVERY(3,
1553 shost_printk(KERN_INFO, shost,
1554 "%s: Sending target reset to target %d\n",
1555 current->comm, id));
1556 rtn = scsi_try_target_reset(scmd);
1557 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1558 SCSI_LOG_ERROR_RECOVERY(3,
1559 shost_printk(KERN_INFO, shost,
1560 "%s: Target reset failed"
1561 " target: %d\n",
1562 current->comm, id));
1563 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1564 if (scmd_id(scmd) != id)
1565 continue;
1566
1567 if (rtn == SUCCESS)
1568 list_move_tail(&scmd->eh_entry, &check_list);
1569 else if (rtn == FAST_IO_FAIL)
1570 scsi_eh_finish_cmd(scmd, done_q);
1571 else
1572 /* push back on work queue for further processing */
1573 list_move(&scmd->eh_entry, work_q);
1574 }
1575 }
1576
1577 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1578}
1579
1580/**
1581 * scsi_eh_bus_reset - send a bus reset
1582 * @shost: &scsi host being recovered.
1583 * @work_q: &list_head for pending commands.
1584 * @done_q: &list_head for processed commands.
1585 */
1586static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1587 struct list_head *work_q,
1588 struct list_head *done_q)
1589{
1590 struct scsi_cmnd *scmd, *chan_scmd, *next;
1591 LIST_HEAD(check_list);
1592 unsigned int channel;
1593 int rtn;
1594
1595 /*
1596 * we really want to loop over the various channels, and do this on
1597 * a channel by channel basis. we should also check to see if any
1598 * of the failed commands are on soft_reset devices, and if so, skip
1599 * the reset.
1600 */
1601
1602 for (channel = 0; channel <= shost->max_channel; channel++) {
1603 if (scsi_host_eh_past_deadline(shost)) {
1604 list_splice_init(&check_list, work_q);
1605 SCSI_LOG_ERROR_RECOVERY(3,
1606 shost_printk(KERN_INFO, shost,
1607 "%s: skip BRST, past eh deadline\n",
1608 current->comm));
1609 return list_empty(work_q);
1610 }
1611
1612 chan_scmd = NULL;
1613 list_for_each_entry(scmd, work_q, eh_entry) {
1614 if (channel == scmd_channel(scmd)) {
1615 chan_scmd = scmd;
1616 break;
1617 /*
1618 * FIXME add back in some support for
1619 * soft_reset devices.
1620 */
1621 }
1622 }
1623
1624 if (!chan_scmd)
1625 continue;
1626 SCSI_LOG_ERROR_RECOVERY(3,
1627 shost_printk(KERN_INFO, shost,
1628 "%s: Sending BRST chan: %d\n",
1629 current->comm, channel));
1630 rtn = scsi_try_bus_reset(chan_scmd);
1631 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1632 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1633 if (channel == scmd_channel(scmd)) {
1634 if (rtn == FAST_IO_FAIL)
1635 scsi_eh_finish_cmd(scmd,
1636 done_q);
1637 else
1638 list_move_tail(&scmd->eh_entry,
1639 &check_list);
1640 }
1641 }
1642 } else {
1643 SCSI_LOG_ERROR_RECOVERY(3,
1644 shost_printk(KERN_INFO, shost,
1645 "%s: BRST failed chan: %d\n",
1646 current->comm, channel));
1647 }
1648 }
1649 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1650}
1651
1652/**
1653 * scsi_eh_host_reset - send a host reset
1654 * @shost: host to be reset.
1655 * @work_q: &list_head for pending commands.
1656 * @done_q: &list_head for processed commands.
1657 */
1658static int scsi_eh_host_reset(struct Scsi_Host *shost,
1659 struct list_head *work_q,
1660 struct list_head *done_q)
1661{
1662 struct scsi_cmnd *scmd, *next;
1663 LIST_HEAD(check_list);
1664 int rtn;
1665
1666 if (!list_empty(work_q)) {
1667 scmd = list_entry(work_q->next,
1668 struct scsi_cmnd, eh_entry);
1669
1670 SCSI_LOG_ERROR_RECOVERY(3,
1671 shost_printk(KERN_INFO, shost,
1672 "%s: Sending HRST\n",
1673 current->comm));
1674
1675 rtn = scsi_try_host_reset(scmd);
1676 if (rtn == SUCCESS) {
1677 list_splice_init(work_q, &check_list);
1678 } else if (rtn == FAST_IO_FAIL) {
1679 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1680 scsi_eh_finish_cmd(scmd, done_q);
1681 }
1682 } else {
1683 SCSI_LOG_ERROR_RECOVERY(3,
1684 shost_printk(KERN_INFO, shost,
1685 "%s: HRST failed\n",
1686 current->comm));
1687 }
1688 }
1689 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1690}
1691
1692/**
1693 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1694 * @work_q: &list_head for pending commands.
1695 * @done_q: &list_head for processed commands.
1696 */
1697static void scsi_eh_offline_sdevs(struct list_head *work_q,
1698 struct list_head *done_q)
1699{
1700 struct scsi_cmnd *scmd, *next;
1701
1702 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1703 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1704 "not ready after error recovery\n");
1705 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1706 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1707 /*
1708 * FIXME: Handle lost cmds.
1709 */
1710 }
1711 scsi_eh_finish_cmd(scmd, done_q);
1712 }
1713 return;
1714}
1715
1716/**
1717 * scsi_noretry_cmd - determine if command should be failed fast
1718 * @scmd: SCSI cmd to examine.
1719 */
1720int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1721{
1722 switch (host_byte(scmd->result)) {
1723 case DID_OK:
1724 break;
1725 case DID_TIME_OUT:
1726 goto check_type;
1727 case DID_BUS_BUSY:
1728 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1729 case DID_PARITY:
1730 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1731 case DID_ERROR:
1732 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1733 status_byte(scmd->result) == RESERVATION_CONFLICT)
1734 return 0;
1735 /* fall through */
1736 case DID_SOFT_ERROR:
1737 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1738 }
1739
1740 if (status_byte(scmd->result) != CHECK_CONDITION)
1741 return 0;
1742
1743check_type:
1744 /*
1745 * assume caller has checked sense and determined
1746 * the check condition was retryable.
1747 */
1748 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1749 scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1750 return 1;
1751 else
1752 return 0;
1753}
1754
1755/**
1756 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1757 * @scmd: SCSI cmd to examine.
1758 *
1759 * Notes:
1760 * This is *only* called when we are examining the status after sending
1761 * out the actual data command. any commands that are queued for error
1762 * recovery (e.g. test_unit_ready) do *not* come through here.
1763 *
1764 * When this routine returns failed, it means the error handler thread
1765 * is woken. In cases where the error code indicates an error that
1766 * doesn't require the error handler read (i.e. we don't need to
1767 * abort/reset), this function should return SUCCESS.
1768 */
1769int scsi_decide_disposition(struct scsi_cmnd *scmd)
1770{
1771 int rtn;
1772
1773 /*
1774 * if the device is offline, then we clearly just pass the result back
1775 * up to the top level.
1776 */
1777 if (!scsi_device_online(scmd->device)) {
1778 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1779 "%s: device offline - report as SUCCESS\n", __func__));
1780 return SUCCESS;
1781 }
1782
1783 /*
1784 * first check the host byte, to see if there is anything in there
1785 * that would indicate what we need to do.
1786 */
1787 switch (host_byte(scmd->result)) {
1788 case DID_PASSTHROUGH:
1789 /*
1790 * no matter what, pass this through to the upper layer.
1791 * nuke this special code so that it looks like we are saying
1792 * did_ok.
1793 */
1794 scmd->result &= 0xff00ffff;
1795 return SUCCESS;
1796 case DID_OK:
1797 /*
1798 * looks good. drop through, and check the next byte.
1799 */
1800 break;
1801 case DID_ABORT:
1802 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1803 set_host_byte(scmd, DID_TIME_OUT);
1804 return SUCCESS;
1805 }
1806 case DID_NO_CONNECT:
1807 case DID_BAD_TARGET:
1808 /*
1809 * note - this means that we just report the status back
1810 * to the top level driver, not that we actually think
1811 * that it indicates SUCCESS.
1812 */
1813 return SUCCESS;
1814 /*
1815 * when the low level driver returns did_soft_error,
1816 * it is responsible for keeping an internal retry counter
1817 * in order to avoid endless loops (db)
1818 *
1819 * actually this is a bug in this function here. we should
1820 * be mindful of the maximum number of retries specified
1821 * and not get stuck in a loop.
1822 */
1823 case DID_SOFT_ERROR:
1824 goto maybe_retry;
1825 case DID_IMM_RETRY:
1826 return NEEDS_RETRY;
1827
1828 case DID_REQUEUE:
1829 return ADD_TO_MLQUEUE;
1830 case DID_TRANSPORT_DISRUPTED:
1831 /*
1832 * LLD/transport was disrupted during processing of the IO.
1833 * The transport class is now blocked/blocking,
1834 * and the transport will decide what to do with the IO
1835 * based on its timers and recovery capablilities if
1836 * there are enough retries.
1837 */
1838 goto maybe_retry;
1839 case DID_TRANSPORT_FAILFAST:
1840 /*
1841 * The transport decided to failfast the IO (most likely
1842 * the fast io fail tmo fired), so send IO directly upwards.
1843 */
1844 return SUCCESS;
1845 case DID_ERROR:
1846 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1847 status_byte(scmd->result) == RESERVATION_CONFLICT)
1848 /*
1849 * execute reservation conflict processing code
1850 * lower down
1851 */
1852 break;
1853 /* fallthrough */
1854 case DID_BUS_BUSY:
1855 case DID_PARITY:
1856 goto maybe_retry;
1857 case DID_TIME_OUT:
1858 /*
1859 * when we scan the bus, we get timeout messages for
1860 * these commands if there is no device available.
1861 * other hosts report did_no_connect for the same thing.
1862 */
1863 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1864 scmd->cmnd[0] == INQUIRY)) {
1865 return SUCCESS;
1866 } else {
1867 return FAILED;
1868 }
1869 case DID_RESET:
1870 return SUCCESS;
1871 default:
1872 return FAILED;
1873 }
1874
1875 /*
1876 * next, check the message byte.
1877 */
1878 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1879 return FAILED;
1880
1881 /*
1882 * check the status byte to see if this indicates anything special.
1883 */
1884 switch (status_byte(scmd->result)) {
1885 case QUEUE_FULL:
1886 scsi_handle_queue_full(scmd->device);
1887 /*
1888 * the case of trying to send too many commands to a
1889 * tagged queueing device.
1890 */
1891 case BUSY:
1892 /*
1893 * device can't talk to us at the moment. Should only
1894 * occur (SAM-3) when the task queue is empty, so will cause
1895 * the empty queue handling to trigger a stall in the
1896 * device.
1897 */
1898 return ADD_TO_MLQUEUE;
1899 case GOOD:
1900 if (scmd->cmnd[0] == REPORT_LUNS)
1901 scmd->device->sdev_target->expecting_lun_change = 0;
1902 scsi_handle_queue_ramp_up(scmd->device);
1903 case COMMAND_TERMINATED:
1904 return SUCCESS;
1905 case TASK_ABORTED:
1906 goto maybe_retry;
1907 case CHECK_CONDITION:
1908 rtn = scsi_check_sense(scmd);
1909 if (rtn == NEEDS_RETRY)
1910 goto maybe_retry;
1911 /* if rtn == FAILED, we have no sense information;
1912 * returning FAILED will wake the error handler thread
1913 * to collect the sense and redo the decide
1914 * disposition */
1915 return rtn;
1916 case CONDITION_GOOD:
1917 case INTERMEDIATE_GOOD:
1918 case INTERMEDIATE_C_GOOD:
1919 case ACA_ACTIVE:
1920 /*
1921 * who knows? FIXME(eric)
1922 */
1923 return SUCCESS;
1924
1925 case RESERVATION_CONFLICT:
1926 sdev_printk(KERN_INFO, scmd->device,
1927 "reservation conflict\n");
1928 set_host_byte(scmd, DID_NEXUS_FAILURE);
1929 return SUCCESS; /* causes immediate i/o error */
1930 default:
1931 return FAILED;
1932 }
1933 return FAILED;
1934
1935 maybe_retry:
1936
1937 /* we requeue for retry because the error was retryable, and
1938 * the request was not marked fast fail. Note that above,
1939 * even if the request is marked fast fail, we still requeue
1940 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1941 if ((++scmd->retries) <= scmd->allowed
1942 && !scsi_noretry_cmd(scmd)) {
1943 return NEEDS_RETRY;
1944 } else {
1945 /*
1946 * no more retries - report this one back to upper level.
1947 */
1948 return SUCCESS;
1949 }
1950}
1951
1952static void eh_lock_door_done(struct request *req, int uptodate)
1953{
1954 __blk_put_request(req->q, req);
1955}
1956
1957/**
1958 * scsi_eh_lock_door - Prevent medium removal for the specified device
1959 * @sdev: SCSI device to prevent medium removal
1960 *
1961 * Locking:
1962 * We must be called from process context.
1963 *
1964 * Notes:
1965 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1966 * head of the devices request queue, and continue.
1967 */
1968static void scsi_eh_lock_door(struct scsi_device *sdev)
1969{
1970 struct request *req;
1971
1972 /*
1973 * blk_get_request with GFP_KERNEL (__GFP_RECLAIM) sleeps until a
1974 * request becomes available
1975 */
1976 req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1977 if (IS_ERR(req))
1978 return;
1979
1980 blk_rq_set_block_pc(req);
1981
1982 req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1983 req->cmd[1] = 0;
1984 req->cmd[2] = 0;
1985 req->cmd[3] = 0;
1986 req->cmd[4] = SCSI_REMOVAL_PREVENT;
1987 req->cmd[5] = 0;
1988
1989 req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1990
1991 req->rq_flags |= RQF_QUIET;
1992 req->timeout = 10 * HZ;
1993 req->retries = 5;
1994
1995 blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1996}
1997
1998/**
1999 * scsi_restart_operations - restart io operations to the specified host.
2000 * @shost: Host we are restarting.
2001 *
2002 * Notes:
2003 * When we entered the error handler, we blocked all further i/o to
2004 * this device. we need to 'reverse' this process.
2005 */
2006static void scsi_restart_operations(struct Scsi_Host *shost)
2007{
2008 struct scsi_device *sdev;
2009 unsigned long flags;
2010
2011 /*
2012 * If the door was locked, we need to insert a door lock request
2013 * onto the head of the SCSI request queue for the device. There
2014 * is no point trying to lock the door of an off-line device.
2015 */
2016 shost_for_each_device(sdev, shost) {
2017 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2018 scsi_eh_lock_door(sdev);
2019 sdev->was_reset = 0;
2020 }
2021 }
2022
2023 /*
2024 * next free up anything directly waiting upon the host. this
2025 * will be requests for character device operations, and also for
2026 * ioctls to queued block devices.
2027 */
2028 SCSI_LOG_ERROR_RECOVERY(3,
2029 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2030
2031 spin_lock_irqsave(shost->host_lock, flags);
2032 if (scsi_host_set_state(shost, SHOST_RUNNING))
2033 if (scsi_host_set_state(shost, SHOST_CANCEL))
2034 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2035 spin_unlock_irqrestore(shost->host_lock, flags);
2036
2037 wake_up(&shost->host_wait);
2038
2039 /*
2040 * finally we need to re-initiate requests that may be pending. we will
2041 * have had everything blocked while error handling is taking place, and
2042 * now that error recovery is done, we will need to ensure that these
2043 * requests are started.
2044 */
2045 scsi_run_host_queues(shost);
2046
2047 /*
2048 * if eh is active and host_eh_scheduled is pending we need to re-run
2049 * recovery. we do this check after scsi_run_host_queues() to allow
2050 * everything pent up since the last eh run a chance to make forward
2051 * progress before we sync again. Either we'll immediately re-run
2052 * recovery or scsi_device_unbusy() will wake us again when these
2053 * pending commands complete.
2054 */
2055 spin_lock_irqsave(shost->host_lock, flags);
2056 if (shost->host_eh_scheduled)
2057 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2058 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2059 spin_unlock_irqrestore(shost->host_lock, flags);
2060}
2061
2062/**
2063 * scsi_eh_ready_devs - check device ready state and recover if not.
2064 * @shost: host to be recovered.
2065 * @work_q: &list_head for pending commands.
2066 * @done_q: &list_head for processed commands.
2067 */
2068void scsi_eh_ready_devs(struct Scsi_Host *shost,
2069 struct list_head *work_q,
2070 struct list_head *done_q)
2071{
2072 if (!scsi_eh_stu(shost, work_q, done_q))
2073 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2074 if (!scsi_eh_target_reset(shost, work_q, done_q))
2075 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2076 if (!scsi_eh_host_reset(shost, work_q, done_q))
2077 scsi_eh_offline_sdevs(work_q,
2078 done_q);
2079}
2080EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2081
2082/**
2083 * scsi_eh_flush_done_q - finish processed commands or retry them.
2084 * @done_q: list_head of processed commands.
2085 */
2086void scsi_eh_flush_done_q(struct list_head *done_q)
2087{
2088 struct scsi_cmnd *scmd, *next;
2089
2090 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2091 list_del_init(&scmd->eh_entry);
2092 if (scsi_device_online(scmd->device) &&
2093 !scsi_noretry_cmd(scmd) &&
2094 (++scmd->retries <= scmd->allowed)) {
2095 SCSI_LOG_ERROR_RECOVERY(3,
2096 scmd_printk(KERN_INFO, scmd,
2097 "%s: flush retry cmd\n",
2098 current->comm));
2099 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2100 } else {
2101 /*
2102 * If just we got sense for the device (called
2103 * scsi_eh_get_sense), scmd->result is already
2104 * set, do not set DRIVER_TIMEOUT.
2105 */
2106 if (!scmd->result)
2107 scmd->result |= (DRIVER_TIMEOUT << 24);
2108 SCSI_LOG_ERROR_RECOVERY(3,
2109 scmd_printk(KERN_INFO, scmd,
2110 "%s: flush finish cmd\n",
2111 current->comm));
2112 scsi_finish_command(scmd);
2113 }
2114 }
2115}
2116EXPORT_SYMBOL(scsi_eh_flush_done_q);
2117
2118/**
2119 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2120 * @shost: Host to unjam.
2121 *
2122 * Notes:
2123 * When we come in here, we *know* that all commands on the bus have
2124 * either completed, failed or timed out. we also know that no further
2125 * commands are being sent to the host, so things are relatively quiet
2126 * and we have freedom to fiddle with things as we wish.
2127 *
2128 * This is only the *default* implementation. it is possible for
2129 * individual drivers to supply their own version of this function, and
2130 * if the maintainer wishes to do this, it is strongly suggested that
2131 * this function be taken as a template and modified. this function
2132 * was designed to correctly handle problems for about 95% of the
2133 * different cases out there, and it should always provide at least a
2134 * reasonable amount of error recovery.
2135 *
2136 * Any command marked 'failed' or 'timeout' must eventually have
2137 * scsi_finish_cmd() called for it. we do all of the retry stuff
2138 * here, so when we restart the host after we return it should have an
2139 * empty queue.
2140 */
2141static void scsi_unjam_host(struct Scsi_Host *shost)
2142{
2143 unsigned long flags;
2144 LIST_HEAD(eh_work_q);
2145 LIST_HEAD(eh_done_q);
2146
2147 spin_lock_irqsave(shost->host_lock, flags);
2148 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2149 spin_unlock_irqrestore(shost->host_lock, flags);
2150
2151 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2152
2153 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2154 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
2155 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2156
2157 spin_lock_irqsave(shost->host_lock, flags);
2158 if (shost->eh_deadline != -1)
2159 shost->last_reset = 0;
2160 spin_unlock_irqrestore(shost->host_lock, flags);
2161 scsi_eh_flush_done_q(&eh_done_q);
2162}
2163
2164/**
2165 * scsi_error_handler - SCSI error handler thread
2166 * @data: Host for which we are running.
2167 *
2168 * Notes:
2169 * This is the main error handling loop. This is run as a kernel thread
2170 * for every SCSI host and handles all error handling activity.
2171 */
2172int scsi_error_handler(void *data)
2173{
2174 struct Scsi_Host *shost = data;
2175
2176 /*
2177 * We use TASK_INTERRUPTIBLE so that the thread is not
2178 * counted against the load average as a running process.
2179 * We never actually get interrupted because kthread_run
2180 * disables signal delivery for the created thread.
2181 */
2182 while (true) {
2183 /*
2184 * The sequence in kthread_stop() sets the stop flag first
2185 * then wakes the process. To avoid missed wakeups, the task
2186 * should always be in a non running state before the stop
2187 * flag is checked
2188 */
2189 set_current_state(TASK_INTERRUPTIBLE);
2190 if (kthread_should_stop())
2191 break;
2192
2193 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2194 shost->host_failed != atomic_read(&shost->host_busy)) {
2195 SCSI_LOG_ERROR_RECOVERY(1,
2196 shost_printk(KERN_INFO, shost,
2197 "scsi_eh_%d: sleeping\n",
2198 shost->host_no));
2199 schedule();
2200 continue;
2201 }
2202
2203 __set_current_state(TASK_RUNNING);
2204 SCSI_LOG_ERROR_RECOVERY(1,
2205 shost_printk(KERN_INFO, shost,
2206 "scsi_eh_%d: waking up %d/%d/%d\n",
2207 shost->host_no, shost->host_eh_scheduled,
2208 shost->host_failed,
2209 atomic_read(&shost->host_busy)));
2210
2211 /*
2212 * We have a host that is failing for some reason. Figure out
2213 * what we need to do to get it up and online again (if we can).
2214 * If we fail, we end up taking the thing offline.
2215 */
2216 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2217 SCSI_LOG_ERROR_RECOVERY(1,
2218 shost_printk(KERN_ERR, shost,
2219 "scsi_eh_%d: unable to autoresume\n",
2220 shost->host_no));
2221 continue;
2222 }
2223
2224 if (shost->transportt->eh_strategy_handler)
2225 shost->transportt->eh_strategy_handler(shost);
2226 else
2227 scsi_unjam_host(shost);
2228
2229 /* All scmds have been handled */
2230 shost->host_failed = 0;
2231
2232 /*
2233 * Note - if the above fails completely, the action is to take
2234 * individual devices offline and flush the queue of any
2235 * outstanding requests that may have been pending. When we
2236 * restart, we restart any I/O to any other devices on the bus
2237 * which are still online.
2238 */
2239 scsi_restart_operations(shost);
2240 if (!shost->eh_noresume)
2241 scsi_autopm_put_host(shost);
2242 }
2243 __set_current_state(TASK_RUNNING);
2244
2245 SCSI_LOG_ERROR_RECOVERY(1,
2246 shost_printk(KERN_INFO, shost,
2247 "Error handler scsi_eh_%d exiting\n",
2248 shost->host_no));
2249 shost->ehandler = NULL;
2250 return 0;
2251}
2252
2253/*
2254 * Function: scsi_report_bus_reset()
2255 *
2256 * Purpose: Utility function used by low-level drivers to report that
2257 * they have observed a bus reset on the bus being handled.
2258 *
2259 * Arguments: shost - Host in question
2260 * channel - channel on which reset was observed.
2261 *
2262 * Returns: Nothing
2263 *
2264 * Lock status: Host lock must be held.
2265 *
2266 * Notes: This only needs to be called if the reset is one which
2267 * originates from an unknown location. Resets originated
2268 * by the mid-level itself don't need to call this, but there
2269 * should be no harm.
2270 *
2271 * The main purpose of this is to make sure that a CHECK_CONDITION
2272 * is properly treated.
2273 */
2274void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2275{
2276 struct scsi_device *sdev;
2277
2278 __shost_for_each_device(sdev, shost) {
2279 if (channel == sdev_channel(sdev))
2280 __scsi_report_device_reset(sdev, NULL);
2281 }
2282}
2283EXPORT_SYMBOL(scsi_report_bus_reset);
2284
2285/*
2286 * Function: scsi_report_device_reset()
2287 *
2288 * Purpose: Utility function used by low-level drivers to report that
2289 * they have observed a device reset on the device being handled.
2290 *
2291 * Arguments: shost - Host in question
2292 * channel - channel on which reset was observed
2293 * target - target on which reset was observed
2294 *
2295 * Returns: Nothing
2296 *
2297 * Lock status: Host lock must be held
2298 *
2299 * Notes: This only needs to be called if the reset is one which
2300 * originates from an unknown location. Resets originated
2301 * by the mid-level itself don't need to call this, but there
2302 * should be no harm.
2303 *
2304 * The main purpose of this is to make sure that a CHECK_CONDITION
2305 * is properly treated.
2306 */
2307void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2308{
2309 struct scsi_device *sdev;
2310
2311 __shost_for_each_device(sdev, shost) {
2312 if (channel == sdev_channel(sdev) &&
2313 target == sdev_id(sdev))
2314 __scsi_report_device_reset(sdev, NULL);
2315 }
2316}
2317EXPORT_SYMBOL(scsi_report_device_reset);
2318
2319static void
2320scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2321{
2322}
2323
2324/**
2325 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2326 * @dev: scsi_device to operate on
2327 * @arg: reset type (see sg.h)
2328 */
2329int
2330scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2331{
2332 struct scsi_cmnd *scmd;
2333 struct Scsi_Host *shost = dev->host;
2334 struct request req;
2335 unsigned long flags;
2336 int error = 0, rtn, val;
2337
2338 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2339 return -EACCES;
2340
2341 error = get_user(val, arg);
2342 if (error)
2343 return error;
2344
2345 if (scsi_autopm_get_host(shost) < 0)
2346 return -EIO;
2347
2348 error = -EIO;
2349 scmd = scsi_get_command(dev, GFP_KERNEL);
2350 if (!scmd)
2351 goto out_put_autopm_host;
2352
2353 blk_rq_init(NULL, &req);
2354 scmd->request = &req;
2355
2356 scmd->cmnd = req.cmd;
2357
2358 scmd->scsi_done = scsi_reset_provider_done_command;
2359 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2360
2361 scmd->cmd_len = 0;
2362
2363 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2364
2365 spin_lock_irqsave(shost->host_lock, flags);
2366 shost->tmf_in_progress = 1;
2367 spin_unlock_irqrestore(shost->host_lock, flags);
2368
2369 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2370 case SG_SCSI_RESET_NOTHING:
2371 rtn = SUCCESS;
2372 break;
2373 case SG_SCSI_RESET_DEVICE:
2374 rtn = scsi_try_bus_device_reset(scmd);
2375 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2376 break;
2377 /* FALLTHROUGH */
2378 case SG_SCSI_RESET_TARGET:
2379 rtn = scsi_try_target_reset(scmd);
2380 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2381 break;
2382 /* FALLTHROUGH */
2383 case SG_SCSI_RESET_BUS:
2384 rtn = scsi_try_bus_reset(scmd);
2385 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2386 break;
2387 /* FALLTHROUGH */
2388 case SG_SCSI_RESET_HOST:
2389 rtn = scsi_try_host_reset(scmd);
2390 if (rtn == SUCCESS)
2391 break;
2392 default:
2393 /* FALLTHROUGH */
2394 rtn = FAILED;
2395 break;
2396 }
2397
2398 error = (rtn == SUCCESS) ? 0 : -EIO;
2399
2400 spin_lock_irqsave(shost->host_lock, flags);
2401 shost->tmf_in_progress = 0;
2402 spin_unlock_irqrestore(shost->host_lock, flags);
2403
2404 /*
2405 * be sure to wake up anyone who was sleeping or had their queue
2406 * suspended while we performed the TMF.
2407 */
2408 SCSI_LOG_ERROR_RECOVERY(3,
2409 shost_printk(KERN_INFO, shost,
2410 "waking up host to restart after TMF\n"));
2411
2412 wake_up(&shost->host_wait);
2413 scsi_run_host_queues(shost);
2414
2415 scsi_put_command(scmd);
2416
2417out_put_autopm_host:
2418 scsi_autopm_put_host(shost);
2419 return error;
2420}
2421EXPORT_SYMBOL(scsi_ioctl_reset);
2422
2423bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2424 struct scsi_sense_hdr *sshdr)
2425{
2426 return scsi_normalize_sense(cmd->sense_buffer,
2427 SCSI_SENSE_BUFFERSIZE, sshdr);
2428}
2429EXPORT_SYMBOL(scsi_command_normalize_sense);
2430
2431/**
2432 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2433 * @sense_buffer: byte array of sense data
2434 * @sb_len: number of valid bytes in sense_buffer
2435 * @info_out: pointer to 64 integer where 8 or 4 byte information
2436 * field will be placed if found.
2437 *
2438 * Return value:
2439 * 1 if information field found, 0 if not found.
2440 */
2441int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2442 u64 * info_out)
2443{
2444 int j;
2445 const u8 * ucp;
2446 u64 ull;
2447
2448 if (sb_len < 7)
2449 return 0;
2450 switch (sense_buffer[0] & 0x7f) {
2451 case 0x70:
2452 case 0x71:
2453 if (sense_buffer[0] & 0x80) {
2454 *info_out = (sense_buffer[3] << 24) +
2455 (sense_buffer[4] << 16) +
2456 (sense_buffer[5] << 8) + sense_buffer[6];
2457 return 1;
2458 } else
2459 return 0;
2460 case 0x72:
2461 case 0x73:
2462 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2463 0 /* info desc */);
2464 if (ucp && (0xa == ucp[1])) {
2465 ull = 0;
2466 for (j = 0; j < 8; ++j) {
2467 if (j > 0)
2468 ull <<= 8;
2469 ull |= ucp[4 + j];
2470 }
2471 *info_out = ull;
2472 return 1;
2473 } else
2474 return 0;
2475 default:
2476 return 0;
2477 }
2478}
2479EXPORT_SYMBOL(scsi_get_sense_info_fld);