[PATCH] SCSI: make scsi_implement_eh() generic API for SCSI transports
[linux-2.6.git] / drivers / scsi / scsi_error.c
1 /*
2  *  scsi_error.c Copyright (C) 1997 Eric Youngdale
3  *
4  *  SCSI error/timeout handling
5  *      Initial versions: Eric Youngdale.  Based upon conversations with
6  *                        Leonard Zubkoff and David Miller at Linux Expo, 
7  *                        ideas originating from all over the place.
8  *
9  *      Restructured scsi_unjam_host and associated functions.
10  *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
11  *
12  *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
13  *      minor  cleanups.
14  *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
15  */
16
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/timer.h>
20 #include <linux/string.h>
21 #include <linux/slab.h>
22 #include <linux/kernel.h>
23 #include <linux/kthread.h>
24 #include <linux/interrupt.h>
25 #include <linux/blkdev.h>
26 #include <linux/delay.h>
27
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_dbg.h>
30 #include <scsi/scsi_device.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_transport.h>
33 #include <scsi/scsi_host.h>
34 #include <scsi/scsi_ioctl.h>
35 #include <scsi/scsi_request.h>
36
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
39
40 #define SENSE_TIMEOUT           (10*HZ)
41 #define START_UNIT_TIMEOUT      (30*HZ)
42
43 /*
44  * These should *probably* be handled by the host itself.
45  * Since it is allowed to sleep, it probably should.
46  */
47 #define BUS_RESET_SETTLE_TIME   (10)
48 #define HOST_RESET_SETTLE_TIME  (10)
49
50 /* called with shost->host_lock held */
51 void scsi_eh_wakeup(struct Scsi_Host *shost)
52 {
53         if (shost->host_busy == shost->host_failed) {
54                 wake_up_process(shost->ehandler);
55                 SCSI_LOG_ERROR_RECOVERY(5,
56                                 printk("Waking error handler thread\n"));
57         }
58 }
59
60 /**
61  * scsi_schedule_eh - schedule EH for SCSI host
62  * @shost:      SCSI host to invoke error handling on.
63  *
64  * Schedule SCSI EH without scmd.
65  **/
66 void scsi_schedule_eh(struct Scsi_Host *shost)
67 {
68         unsigned long flags;
69
70         spin_lock_irqsave(shost->host_lock, flags);
71
72         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
73             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
74                 shost->host_eh_scheduled++;
75                 scsi_eh_wakeup(shost);
76         }
77
78         spin_unlock_irqrestore(shost->host_lock, flags);
79 }
80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
81
82 /**
83  * scsi_eh_scmd_add - add scsi cmd to error handling.
84  * @scmd:       scmd to run eh on.
85  * @eh_flag:    optional SCSI_EH flag.
86  *
87  * Return value:
88  *      0 on failure.
89  **/
90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
91 {
92         struct Scsi_Host *shost = scmd->device->host;
93         unsigned long flags;
94         int ret = 0;
95
96         if (!shost->ehandler)
97                 return 0;
98
99         spin_lock_irqsave(shost->host_lock, flags);
100         if (scsi_host_set_state(shost, SHOST_RECOVERY))
101                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
102                         goto out_unlock;
103
104         ret = 1;
105         scmd->eh_eflags |= eh_flag;
106         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
107         shost->host_failed++;
108         scsi_eh_wakeup(shost);
109  out_unlock:
110         spin_unlock_irqrestore(shost->host_lock, flags);
111         return ret;
112 }
113
114 /**
115  * scsi_add_timer - Start timeout timer for a single scsi command.
116  * @scmd:       scsi command that is about to start running.
117  * @timeout:    amount of time to allow this command to run.
118  * @complete:   timeout function to call if timer isn't canceled.
119  *
120  * Notes:
121  *    This should be turned into an inline function.  Each scsi command
122  *    has its own timer, and as it is added to the queue, we set up the
123  *    timer.  When the command completes, we cancel the timer.
124  **/
125 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
126                     void (*complete)(struct scsi_cmnd *))
127 {
128
129         /*
130          * If the clock was already running for this command, then
131          * first delete the timer.  The timer handling code gets rather
132          * confused if we don't do this.
133          */
134         if (scmd->eh_timeout.function)
135                 del_timer(&scmd->eh_timeout);
136
137         scmd->eh_timeout.data = (unsigned long)scmd;
138         scmd->eh_timeout.expires = jiffies + timeout;
139         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
140
141         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
142                                           " %d, (%p)\n", __FUNCTION__,
143                                           scmd, timeout, complete));
144
145         add_timer(&scmd->eh_timeout);
146 }
147
148 /**
149  * scsi_delete_timer - Delete/cancel timer for a given function.
150  * @scmd:       Cmd that we are canceling timer for
151  *
152  * Notes:
153  *     This should be turned into an inline function.
154  *
155  * Return value:
156  *     1 if we were able to detach the timer.  0 if we blew it, and the
157  *     timer function has already started to run.
158  **/
159 int scsi_delete_timer(struct scsi_cmnd *scmd)
160 {
161         int rtn;
162
163         rtn = del_timer(&scmd->eh_timeout);
164
165         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
166                                          " rtn: %d\n", __FUNCTION__,
167                                          scmd, rtn));
168
169         scmd->eh_timeout.data = (unsigned long)NULL;
170         scmd->eh_timeout.function = NULL;
171
172         return rtn;
173 }
174
175 /**
176  * scsi_times_out - Timeout function for normal scsi commands.
177  * @scmd:       Cmd that is timing out.
178  *
179  * Notes:
180  *     We do not need to lock this.  There is the potential for a race
181  *     only in that the normal completion handling might run, but if the
182  *     normal completion function determines that the timer has already
183  *     fired, then it mustn't do anything.
184  **/
185 void scsi_times_out(struct scsi_cmnd *scmd)
186 {
187         scsi_log_completion(scmd, TIMEOUT_ERROR);
188
189         if (scmd->device->host->transportt->eh_timed_out)
190                 switch (scmd->device->host->transportt->eh_timed_out(scmd)) {
191                 case EH_HANDLED:
192                         __scsi_done(scmd);
193                         return;
194                 case EH_RESET_TIMER:
195                         scsi_add_timer(scmd, scmd->timeout_per_command,
196                                        scsi_times_out);
197                         return;
198                 case EH_NOT_HANDLED:
199                         break;
200                 }
201
202         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
203                 scmd->result |= DID_TIME_OUT << 16;
204                 __scsi_done(scmd);
205         }
206 }
207
208 /**
209  * scsi_block_when_processing_errors - Prevent cmds from being queued.
210  * @sdev:       Device on which we are performing recovery.
211  *
212  * Description:
213  *     We block until the host is out of error recovery, and then check to
214  *     see whether the host or the device is offline.
215  *
216  * Return value:
217  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
218  **/
219 int scsi_block_when_processing_errors(struct scsi_device *sdev)
220 {
221         int online;
222
223         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
224
225         online = scsi_device_online(sdev);
226
227         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
228                                           online));
229
230         return online;
231 }
232 EXPORT_SYMBOL(scsi_block_when_processing_errors);
233
234 #ifdef CONFIG_SCSI_LOGGING
235 /**
236  * scsi_eh_prt_fail_stats - Log info on failures.
237  * @shost:      scsi host being recovered.
238  * @work_q:     Queue of scsi cmds to process.
239  **/
240 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
241                                           struct list_head *work_q)
242 {
243         struct scsi_cmnd *scmd;
244         struct scsi_device *sdev;
245         int total_failures = 0;
246         int cmd_failed = 0;
247         int cmd_cancel = 0;
248         int devices_failed = 0;
249
250         shost_for_each_device(sdev, shost) {
251                 list_for_each_entry(scmd, work_q, eh_entry) {
252                         if (scmd->device == sdev) {
253                                 ++total_failures;
254                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
255                                         ++cmd_cancel;
256                                 else 
257                                         ++cmd_failed;
258                         }
259                 }
260
261                 if (cmd_cancel || cmd_failed) {
262                         SCSI_LOG_ERROR_RECOVERY(3,
263                                 sdev_printk(KERN_INFO, sdev,
264                                             "%s: cmds failed: %d, cancel: %d\n",
265                                             __FUNCTION__, cmd_failed,
266                                             cmd_cancel));
267                         cmd_cancel = 0;
268                         cmd_failed = 0;
269                         ++devices_failed;
270                 }
271         }
272
273         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
274                                           " devices require eh work\n",
275                                   total_failures, devices_failed));
276 }
277 #endif
278
279 /**
280  * scsi_check_sense - Examine scsi cmd sense
281  * @scmd:       Cmd to have sense checked.
282  *
283  * Return value:
284  *      SUCCESS or FAILED or NEEDS_RETRY
285  *
286  * Notes:
287  *      When a deferred error is detected the current command has
288  *      not been executed and needs retrying.
289  **/
290 static int scsi_check_sense(struct scsi_cmnd *scmd)
291 {
292         struct scsi_sense_hdr sshdr;
293
294         if (! scsi_command_normalize_sense(scmd, &sshdr))
295                 return FAILED;  /* no valid sense data */
296
297         if (scsi_sense_is_deferred(&sshdr))
298                 return NEEDS_RETRY;
299
300         /*
301          * Previous logic looked for FILEMARK, EOM or ILI which are
302          * mainly associated with tapes and returned SUCCESS.
303          */
304         if (sshdr.response_code == 0x70) {
305                 /* fixed format */
306                 if (scmd->sense_buffer[2] & 0xe0)
307                         return SUCCESS;
308         } else {
309                 /*
310                  * descriptor format: look for "stream commands sense data
311                  * descriptor" (see SSC-3). Assume single sense data
312                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
313                  */
314                 if ((sshdr.additional_length > 3) &&
315                     (scmd->sense_buffer[8] == 0x4) &&
316                     (scmd->sense_buffer[11] & 0xe0))
317                         return SUCCESS;
318         }
319
320         switch (sshdr.sense_key) {
321         case NO_SENSE:
322                 return SUCCESS;
323         case RECOVERED_ERROR:
324                 return /* soft_error */ SUCCESS;
325
326         case ABORTED_COMMAND:
327                 return NEEDS_RETRY;
328         case NOT_READY:
329         case UNIT_ATTENTION:
330                 /*
331                  * if we are expecting a cc/ua because of a bus reset that we
332                  * performed, treat this just as a retry.  otherwise this is
333                  * information that we should pass up to the upper-level driver
334                  * so that we can deal with it there.
335                  */
336                 if (scmd->device->expecting_cc_ua) {
337                         scmd->device->expecting_cc_ua = 0;
338                         return NEEDS_RETRY;
339                 }
340                 /*
341                  * if the device is in the process of becoming ready, we 
342                  * should retry.
343                  */
344                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
345                         return NEEDS_RETRY;
346                 /*
347                  * if the device is not started, we need to wake
348                  * the error handler to start the motor
349                  */
350                 if (scmd->device->allow_restart &&
351                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
352                         return FAILED;
353                 return SUCCESS;
354
355                 /* these three are not supported */
356         case COPY_ABORTED:
357         case VOLUME_OVERFLOW:
358         case MISCOMPARE:
359                 return SUCCESS;
360
361         case MEDIUM_ERROR:
362                 return NEEDS_RETRY;
363
364         case HARDWARE_ERROR:
365                 if (scmd->device->retry_hwerror)
366                         return NEEDS_RETRY;
367                 else
368                         return SUCCESS;
369
370         case ILLEGAL_REQUEST:
371         case BLANK_CHECK:
372         case DATA_PROTECT:
373         default:
374                 return SUCCESS;
375         }
376 }
377
378 /**
379  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
380  * @scmd:       SCSI cmd to examine.
381  *
382  * Notes:
383  *    This is *only* called when we are examining the status of commands
384  *    queued during error recovery.  the main difference here is that we
385  *    don't allow for the possibility of retries here, and we are a lot
386  *    more restrictive about what we consider acceptable.
387  **/
388 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
389 {
390         /*
391          * first check the host byte, to see if there is anything in there
392          * that would indicate what we need to do.
393          */
394         if (host_byte(scmd->result) == DID_RESET) {
395                 /*
396                  * rats.  we are already in the error handler, so we now
397                  * get to try and figure out what to do next.  if the sense
398                  * is valid, we have a pretty good idea of what to do.
399                  * if not, we mark it as FAILED.
400                  */
401                 return scsi_check_sense(scmd);
402         }
403         if (host_byte(scmd->result) != DID_OK)
404                 return FAILED;
405
406         /*
407          * next, check the message byte.
408          */
409         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
410                 return FAILED;
411
412         /*
413          * now, check the status byte to see if this indicates
414          * anything special.
415          */
416         switch (status_byte(scmd->result)) {
417         case GOOD:
418         case COMMAND_TERMINATED:
419                 return SUCCESS;
420         case CHECK_CONDITION:
421                 return scsi_check_sense(scmd);
422         case CONDITION_GOOD:
423         case INTERMEDIATE_GOOD:
424         case INTERMEDIATE_C_GOOD:
425                 /*
426                  * who knows?  FIXME(eric)
427                  */
428                 return SUCCESS;
429         case BUSY:
430         case QUEUE_FULL:
431         case RESERVATION_CONFLICT:
432         default:
433                 return FAILED;
434         }
435         return FAILED;
436 }
437
438 /**
439  * scsi_eh_done - Completion function for error handling.
440  * @scmd:       Cmd that is done.
441  **/
442 static void scsi_eh_done(struct scsi_cmnd *scmd)
443 {
444         struct completion     *eh_action;
445
446         SCSI_LOG_ERROR_RECOVERY(3,
447                 printk("%s scmd: %p result: %x\n",
448                         __FUNCTION__, scmd, scmd->result));
449
450         eh_action = scmd->device->host->eh_action;
451         if (eh_action)
452                 complete(eh_action);
453 }
454
455 /**
456  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
457  * @scmd:       SCSI Cmd to send.
458  * @timeout:    Timeout for cmd.
459  *
460  * Return value:
461  *    SUCCESS or FAILED or NEEDS_RETRY
462  **/
463 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
464 {
465         struct scsi_device *sdev = scmd->device;
466         struct Scsi_Host *shost = sdev->host;
467         DECLARE_COMPLETION(done);
468         unsigned long timeleft;
469         unsigned long flags;
470         int rtn;
471
472         if (sdev->scsi_level <= SCSI_2)
473                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
474                         (sdev->lun << 5 & 0xe0);
475
476         shost->eh_action = &done;
477         scmd->request->rq_status = RQ_SCSI_BUSY;
478
479         spin_lock_irqsave(shost->host_lock, flags);
480         scsi_log_send(scmd);
481         shost->hostt->queuecommand(scmd, scsi_eh_done);
482         spin_unlock_irqrestore(shost->host_lock, flags);
483
484         timeleft = wait_for_completion_timeout(&done, timeout);
485
486         scmd->request->rq_status = RQ_SCSI_DONE;
487         shost->eh_action = NULL;
488
489         scsi_log_completion(scmd, SUCCESS);
490
491         SCSI_LOG_ERROR_RECOVERY(3,
492                 printk("%s: scmd: %p, timeleft: %ld\n",
493                         __FUNCTION__, scmd, timeleft));
494
495         /*
496          * If there is time left scsi_eh_done got called, and we will
497          * examine the actual status codes to see whether the command
498          * actually did complete normally, else tell the host to forget
499          * about this command.
500          */
501         if (timeleft) {
502                 rtn = scsi_eh_completed_normally(scmd);
503                 SCSI_LOG_ERROR_RECOVERY(3,
504                         printk("%s: scsi_eh_completed_normally %x\n",
505                                __FUNCTION__, rtn));
506
507                 switch (rtn) {
508                 case SUCCESS:
509                 case NEEDS_RETRY:
510                 case FAILED:
511                         break;
512                 default:
513                         rtn = FAILED;
514                         break;
515                 }
516         } else {
517                 /*
518                  * FIXME(eric) - we are not tracking whether we could
519                  * abort a timed out command or not.  not sure how
520                  * we should treat them differently anyways.
521                  */
522                 if (shost->hostt->eh_abort_handler)
523                         shost->hostt->eh_abort_handler(scmd);
524                 rtn = FAILED;
525         }
526
527         return rtn;
528 }
529
530 /**
531  * scsi_request_sense - Request sense data from a particular target.
532  * @scmd:       SCSI cmd for request sense.
533  *
534  * Notes:
535  *    Some hosts automatically obtain this information, others require
536  *    that we obtain it on our own. This function will *not* return until
537  *    the command either times out, or it completes.
538  **/
539 static int scsi_request_sense(struct scsi_cmnd *scmd)
540 {
541         static unsigned char generic_sense[6] =
542         {REQUEST_SENSE, 0, 0, 0, 252, 0};
543         unsigned char *scsi_result;
544         int saved_result;
545         int rtn;
546
547         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
548
549         scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
550
551
552         if (unlikely(!scsi_result)) {
553                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
554                        __FUNCTION__);
555                 return FAILED;
556         }
557
558         /*
559          * zero the sense buffer.  some host adapters automatically always
560          * request sense, so it is not a good idea that
561          * scmd->request_buffer and scmd->sense_buffer point to the same
562          * address (db).  0 is not a valid sense code. 
563          */
564         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
565         memset(scsi_result, 0, 252);
566
567         saved_result = scmd->result;
568         scmd->request_buffer = scsi_result;
569         scmd->request_bufflen = 252;
570         scmd->use_sg = 0;
571         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
572         scmd->sc_data_direction = DMA_FROM_DEVICE;
573         scmd->underflow = 0;
574
575         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
576
577         /* last chance to have valid sense data */
578         if(!SCSI_SENSE_VALID(scmd)) {
579                 memcpy(scmd->sense_buffer, scmd->request_buffer,
580                        sizeof(scmd->sense_buffer));
581         }
582
583         kfree(scsi_result);
584
585         /*
586          * when we eventually call scsi_finish, we really wish to complete
587          * the original request, so let's restore the original data. (db)
588          */
589         scsi_setup_cmd_retry(scmd);
590         scmd->result = saved_result;
591         return rtn;
592 }
593
594 /**
595  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
596  * @scmd:       Original SCSI cmd that eh has finished.
597  * @done_q:     Queue for processed commands.
598  *
599  * Notes:
600  *    We don't want to use the normal command completion while we are are
601  *    still handling errors - it may cause other commands to be queued,
602  *    and that would disturb what we are doing.  thus we really want to
603  *    keep a list of pending commands for final completion, and once we
604  *    are ready to leave error handling we handle completion for real.
605  **/
606 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
607 {
608         scmd->device->host->host_failed--;
609         scmd->eh_eflags = 0;
610
611         /*
612          * set this back so that the upper level can correctly free up
613          * things.
614          */
615         scsi_setup_cmd_retry(scmd);
616         list_move_tail(&scmd->eh_entry, done_q);
617 }
618 EXPORT_SYMBOL(scsi_eh_finish_cmd);
619
620 /**
621  * scsi_eh_get_sense - Get device sense data.
622  * @work_q:     Queue of commands to process.
623  * @done_q:     Queue of proccessed commands..
624  *
625  * Description:
626  *    See if we need to request sense information.  if so, then get it
627  *    now, so we have a better idea of what to do.  
628  *
629  * Notes:
630  *    This has the unfortunate side effect that if a shost adapter does
631  *    not automatically request sense information, that we end up shutting
632  *    it down before we request it.
633  *
634  *    All drivers should request sense information internally these days,
635  *    so for now all I have to say is tough noogies if you end up in here.
636  *
637  *    XXX: Long term this code should go away, but that needs an audit of
638  *         all LLDDs first.
639  **/
640 static int scsi_eh_get_sense(struct list_head *work_q,
641                              struct list_head *done_q)
642 {
643         struct scsi_cmnd *scmd, *next;
644         int rtn;
645
646         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
647                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
648                     SCSI_SENSE_VALID(scmd))
649                         continue;
650
651                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
652                                                   "%s: requesting sense\n",
653                                                   current->comm));
654                 rtn = scsi_request_sense(scmd);
655                 if (rtn != SUCCESS)
656                         continue;
657
658                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
659                                                   " result %x\n", scmd,
660                                                   scmd->result));
661                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
662
663                 rtn = scsi_decide_disposition(scmd);
664
665                 /*
666                  * if the result was normal, then just pass it along to the
667                  * upper level.
668                  */
669                 if (rtn == SUCCESS)
670                         /* we don't want this command reissued, just
671                          * finished with the sense data, so set
672                          * retries to the max allowed to ensure it
673                          * won't get reissued */
674                         scmd->retries = scmd->allowed;
675                 else if (rtn != NEEDS_RETRY)
676                         continue;
677
678                 scsi_eh_finish_cmd(scmd, done_q);
679         }
680
681         return list_empty(work_q);
682 }
683
684 /**
685  * scsi_try_to_abort_cmd - Ask host to abort a running command.
686  * @scmd:       SCSI cmd to abort from Lower Level.
687  *
688  * Notes:
689  *    This function will not return until the user's completion function
690  *    has been called.  there is no timeout on this operation.  if the
691  *    author of the low-level driver wishes this operation to be timed,
692  *    they can provide this facility themselves.  helper functions in
693  *    scsi_error.c can be supplied to make this easier to do.
694  **/
695 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
696 {
697         if (!scmd->device->host->hostt->eh_abort_handler)
698                 return FAILED;
699
700         /*
701          * scsi_done was called just after the command timed out and before
702          * we had a chance to process it. (db)
703          */
704         if (scmd->serial_number == 0)
705                 return SUCCESS;
706         return scmd->device->host->hostt->eh_abort_handler(scmd);
707 }
708
709 /**
710  * scsi_eh_tur - Send TUR to device.
711  * @scmd:       Scsi cmd to send TUR
712  *
713  * Return value:
714  *    0 - Device is ready. 1 - Device NOT ready.
715  **/
716 static int scsi_eh_tur(struct scsi_cmnd *scmd)
717 {
718         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
719         int retry_cnt = 1, rtn;
720         int saved_result;
721
722 retry_tur:
723         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
724
725         /*
726          * zero the sense buffer.  the scsi spec mandates that any
727          * untransferred sense data should be interpreted as being zero.
728          */
729         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
730
731         saved_result = scmd->result;
732         scmd->request_buffer = NULL;
733         scmd->request_bufflen = 0;
734         scmd->use_sg = 0;
735         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
736         scmd->underflow = 0;
737         scmd->sc_data_direction = DMA_NONE;
738
739         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
740
741         /*
742          * when we eventually call scsi_finish, we really wish to complete
743          * the original request, so let's restore the original data. (db)
744          */
745         scsi_setup_cmd_retry(scmd);
746         scmd->result = saved_result;
747
748         /*
749          * hey, we are done.  let's look to see what happened.
750          */
751         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
752                 __FUNCTION__, scmd, rtn));
753         if (rtn == SUCCESS)
754                 return 0;
755         else if (rtn == NEEDS_RETRY) {
756                 if (retry_cnt--)
757                         goto retry_tur;
758                 return 0;
759         }
760         return 1;
761 }
762
763 /**
764  * scsi_eh_abort_cmds - abort canceled commands.
765  * @shost:      scsi host being recovered.
766  * @eh_done_q:  list_head for processed commands.
767  *
768  * Decription:
769  *    Try and see whether or not it makes sense to try and abort the
770  *    running command.  this only works out to be the case if we have one
771  *    command that has timed out.  if the command simply failed, it makes
772  *    no sense to try and abort the command, since as far as the shost
773  *    adapter is concerned, it isn't running.
774  **/
775 static int scsi_eh_abort_cmds(struct list_head *work_q,
776                               struct list_head *done_q)
777 {
778         struct scsi_cmnd *scmd, *next;
779         int rtn;
780
781         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
782                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
783                         continue;
784                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
785                                                   "0x%p\n", current->comm,
786                                                   scmd));
787                 rtn = scsi_try_to_abort_cmd(scmd);
788                 if (rtn == SUCCESS) {
789                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
790                         if (!scsi_device_online(scmd->device) ||
791                             !scsi_eh_tur(scmd)) {
792                                 scsi_eh_finish_cmd(scmd, done_q);
793                         }
794                                 
795                 } else
796                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
797                                                           " cmd failed:"
798                                                           "0x%p\n",
799                                                           current->comm,
800                                                           scmd));
801         }
802
803         return list_empty(work_q);
804 }
805
806 /**
807  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
808  * @scmd:       SCSI cmd used to send BDR       
809  *
810  * Notes:
811  *    There is no timeout for this operation.  if this operation is
812  *    unreliable for a given host, then the host itself needs to put a
813  *    timer on it, and set the host back to a consistent state prior to
814  *    returning.
815  **/
816 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
817 {
818         int rtn;
819
820         if (!scmd->device->host->hostt->eh_device_reset_handler)
821                 return FAILED;
822
823         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
824         if (rtn == SUCCESS) {
825                 scmd->device->was_reset = 1;
826                 scmd->device->expecting_cc_ua = 1;
827         }
828
829         return rtn;
830 }
831
832 /**
833  * scsi_eh_try_stu - Send START_UNIT to device.
834  * @scmd:       Scsi cmd to send START_UNIT
835  *
836  * Return value:
837  *    0 - Device is ready. 1 - Device NOT ready.
838  **/
839 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
840 {
841         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
842         int rtn;
843         int saved_result;
844
845         if (!scmd->device->allow_restart)
846                 return 1;
847
848         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
849
850         /*
851          * zero the sense buffer.  the scsi spec mandates that any
852          * untransferred sense data should be interpreted as being zero.
853          */
854         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
855
856         saved_result = scmd->result;
857         scmd->request_buffer = NULL;
858         scmd->request_bufflen = 0;
859         scmd->use_sg = 0;
860         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
861         scmd->underflow = 0;
862         scmd->sc_data_direction = DMA_NONE;
863
864         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
865
866         /*
867          * when we eventually call scsi_finish, we really wish to complete
868          * the original request, so let's restore the original data. (db)
869          */
870         scsi_setup_cmd_retry(scmd);
871         scmd->result = saved_result;
872
873         /*
874          * hey, we are done.  let's look to see what happened.
875          */
876         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
877                 __FUNCTION__, scmd, rtn));
878         if (rtn == SUCCESS)
879                 return 0;
880         return 1;
881 }
882
883  /**
884  * scsi_eh_stu - send START_UNIT if needed
885  * @shost:      scsi host being recovered.
886  * @eh_done_q:  list_head for processed commands.
887  *
888  * Notes:
889  *    If commands are failing due to not ready, initializing command required,
890  *      try revalidating the device, which will end up sending a start unit. 
891  **/
892 static int scsi_eh_stu(struct Scsi_Host *shost,
893                               struct list_head *work_q,
894                               struct list_head *done_q)
895 {
896         struct scsi_cmnd *scmd, *stu_scmd, *next;
897         struct scsi_device *sdev;
898
899         shost_for_each_device(sdev, shost) {
900                 stu_scmd = NULL;
901                 list_for_each_entry(scmd, work_q, eh_entry)
902                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
903                             scsi_check_sense(scmd) == FAILED ) {
904                                 stu_scmd = scmd;
905                                 break;
906                         }
907
908                 if (!stu_scmd)
909                         continue;
910
911                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
912                                                   " 0x%p\n", current->comm, sdev));
913
914                 if (!scsi_eh_try_stu(stu_scmd)) {
915                         if (!scsi_device_online(sdev) ||
916                             !scsi_eh_tur(stu_scmd)) {
917                                 list_for_each_entry_safe(scmd, next,
918                                                           work_q, eh_entry) {
919                                         if (scmd->device == sdev)
920                                                 scsi_eh_finish_cmd(scmd, done_q);
921                                 }
922                         }
923                 } else {
924                         SCSI_LOG_ERROR_RECOVERY(3,
925                                                 printk("%s: START_UNIT failed to sdev:"
926                                                        " 0x%p\n", current->comm, sdev));
927                 }
928         }
929
930         return list_empty(work_q);
931 }
932
933
934 /**
935  * scsi_eh_bus_device_reset - send bdr if needed
936  * @shost:      scsi host being recovered.
937  * @eh_done_q:  list_head for processed commands.
938  *
939  * Notes:
940  *    Try a bus device reset.  still, look to see whether we have multiple
941  *    devices that are jammed or not - if we have multiple devices, it
942  *    makes no sense to try bus_device_reset - we really would need to try
943  *    a bus_reset instead. 
944  **/
945 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
946                                     struct list_head *work_q,
947                                     struct list_head *done_q)
948 {
949         struct scsi_cmnd *scmd, *bdr_scmd, *next;
950         struct scsi_device *sdev;
951         int rtn;
952
953         shost_for_each_device(sdev, shost) {
954                 bdr_scmd = NULL;
955                 list_for_each_entry(scmd, work_q, eh_entry)
956                         if (scmd->device == sdev) {
957                                 bdr_scmd = scmd;
958                                 break;
959                         }
960
961                 if (!bdr_scmd)
962                         continue;
963
964                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
965                                                   " 0x%p\n", current->comm,
966                                                   sdev));
967                 rtn = scsi_try_bus_device_reset(bdr_scmd);
968                 if (rtn == SUCCESS) {
969                         if (!scsi_device_online(sdev) ||
970                             !scsi_eh_tur(bdr_scmd)) {
971                                 list_for_each_entry_safe(scmd, next,
972                                                          work_q, eh_entry) {
973                                         if (scmd->device == sdev)
974                                                 scsi_eh_finish_cmd(scmd,
975                                                                    done_q);
976                                 }
977                         }
978                 } else {
979                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
980                                                           " failed sdev:"
981                                                           "0x%p\n",
982                                                           current->comm,
983                                                            sdev));
984                 }
985         }
986
987         return list_empty(work_q);
988 }
989
990 /**
991  * scsi_try_bus_reset - ask host to perform a bus reset
992  * @scmd:       SCSI cmd to send bus reset.
993  **/
994 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
995 {
996         unsigned long flags;
997         int rtn;
998
999         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1000                                           __FUNCTION__));
1001
1002         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1003                 return FAILED;
1004
1005         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1006
1007         if (rtn == SUCCESS) {
1008                 if (!scmd->device->host->hostt->skip_settle_delay)
1009                         ssleep(BUS_RESET_SETTLE_TIME);
1010                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1011                 scsi_report_bus_reset(scmd->device->host,
1012                                       scmd_channel(scmd));
1013                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1014         }
1015
1016         return rtn;
1017 }
1018
1019 /**
1020  * scsi_try_host_reset - ask host adapter to reset itself
1021  * @scmd:       SCSI cmd to send hsot reset.
1022  **/
1023 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1024 {
1025         unsigned long flags;
1026         int rtn;
1027
1028         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1029                                           __FUNCTION__));
1030
1031         if (!scmd->device->host->hostt->eh_host_reset_handler)
1032                 return FAILED;
1033
1034         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1035
1036         if (rtn == SUCCESS) {
1037                 if (!scmd->device->host->hostt->skip_settle_delay)
1038                         ssleep(HOST_RESET_SETTLE_TIME);
1039                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1040                 scsi_report_bus_reset(scmd->device->host,
1041                                       scmd_channel(scmd));
1042                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1043         }
1044
1045         return rtn;
1046 }
1047
1048 /**
1049  * scsi_eh_bus_reset - send a bus reset 
1050  * @shost:      scsi host being recovered.
1051  * @eh_done_q:  list_head for processed commands.
1052  **/
1053 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1054                              struct list_head *work_q,
1055                              struct list_head *done_q)
1056 {
1057         struct scsi_cmnd *scmd, *chan_scmd, *next;
1058         unsigned int channel;
1059         int rtn;
1060
1061         /*
1062          * we really want to loop over the various channels, and do this on
1063          * a channel by channel basis.  we should also check to see if any
1064          * of the failed commands are on soft_reset devices, and if so, skip
1065          * the reset.  
1066          */
1067
1068         for (channel = 0; channel <= shost->max_channel; channel++) {
1069                 chan_scmd = NULL;
1070                 list_for_each_entry(scmd, work_q, eh_entry) {
1071                         if (channel == scmd_channel(scmd)) {
1072                                 chan_scmd = scmd;
1073                                 break;
1074                                 /*
1075                                  * FIXME add back in some support for
1076                                  * soft_reset devices.
1077                                  */
1078                         }
1079                 }
1080
1081                 if (!chan_scmd)
1082                         continue;
1083                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1084                                                   " %d\n", current->comm,
1085                                                   channel));
1086                 rtn = scsi_try_bus_reset(chan_scmd);
1087                 if (rtn == SUCCESS) {
1088                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1089                                 if (channel == scmd_channel(scmd))
1090                                         if (!scsi_device_online(scmd->device) ||
1091                                             !scsi_eh_tur(scmd))
1092                                                 scsi_eh_finish_cmd(scmd,
1093                                                                    done_q);
1094                         }
1095                 } else {
1096                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1097                                                           " failed chan: %d\n",
1098                                                           current->comm,
1099                                                           channel));
1100                 }
1101         }
1102         return list_empty(work_q);
1103 }
1104
1105 /**
1106  * scsi_eh_host_reset - send a host reset 
1107  * @work_q:     list_head for processed commands.
1108  * @done_q:     list_head for processed commands.
1109  **/
1110 static int scsi_eh_host_reset(struct list_head *work_q,
1111                               struct list_head *done_q)
1112 {
1113         struct scsi_cmnd *scmd, *next;
1114         int rtn;
1115
1116         if (!list_empty(work_q)) {
1117                 scmd = list_entry(work_q->next,
1118                                   struct scsi_cmnd, eh_entry);
1119
1120                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1121                                                   , current->comm));
1122
1123                 rtn = scsi_try_host_reset(scmd);
1124                 if (rtn == SUCCESS) {
1125                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1126                                 if (!scsi_device_online(scmd->device) ||
1127                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1128                                     !scsi_eh_tur(scmd))
1129                                         scsi_eh_finish_cmd(scmd, done_q);
1130                         }
1131                 } else {
1132                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1133                                                           " failed\n",
1134                                                           current->comm));
1135                 }
1136         }
1137         return list_empty(work_q);
1138 }
1139
1140 /**
1141  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1142  * @work_q:     list_head for processed commands.
1143  * @done_q:     list_head for processed commands.
1144  *
1145  **/
1146 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1147                                   struct list_head *done_q)
1148 {
1149         struct scsi_cmnd *scmd, *next;
1150
1151         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1152                 sdev_printk(KERN_INFO, scmd->device,
1153                             "scsi: Device offlined - not"
1154                             " ready after error recovery\n");
1155                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1156                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1157                         /*
1158                          * FIXME: Handle lost cmds.
1159                          */
1160                 }
1161                 scsi_eh_finish_cmd(scmd, done_q);
1162         }
1163         return;
1164 }
1165
1166 /**
1167  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1168  * @scmd:       SCSI cmd to examine.
1169  *
1170  * Notes:
1171  *    This is *only* called when we are examining the status after sending
1172  *    out the actual data command.  any commands that are queued for error
1173  *    recovery (e.g. test_unit_ready) do *not* come through here.
1174  *
1175  *    When this routine returns failed, it means the error handler thread
1176  *    is woken.  In cases where the error code indicates an error that
1177  *    doesn't require the error handler read (i.e. we don't need to
1178  *    abort/reset), this function should return SUCCESS.
1179  **/
1180 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1181 {
1182         int rtn;
1183
1184         /*
1185          * if the device is offline, then we clearly just pass the result back
1186          * up to the top level.
1187          */
1188         if (!scsi_device_online(scmd->device)) {
1189                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1190                                                   " as SUCCESS\n",
1191                                                   __FUNCTION__));
1192                 return SUCCESS;
1193         }
1194
1195         /*
1196          * first check the host byte, to see if there is anything in there
1197          * that would indicate what we need to do.
1198          */
1199         switch (host_byte(scmd->result)) {
1200         case DID_PASSTHROUGH:
1201                 /*
1202                  * no matter what, pass this through to the upper layer.
1203                  * nuke this special code so that it looks like we are saying
1204                  * did_ok.
1205                  */
1206                 scmd->result &= 0xff00ffff;
1207                 return SUCCESS;
1208         case DID_OK:
1209                 /*
1210                  * looks good.  drop through, and check the next byte.
1211                  */
1212                 break;
1213         case DID_NO_CONNECT:
1214         case DID_BAD_TARGET:
1215         case DID_ABORT:
1216                 /*
1217                  * note - this means that we just report the status back
1218                  * to the top level driver, not that we actually think
1219                  * that it indicates SUCCESS.
1220                  */
1221                 return SUCCESS;
1222                 /*
1223                  * when the low level driver returns did_soft_error,
1224                  * it is responsible for keeping an internal retry counter 
1225                  * in order to avoid endless loops (db)
1226                  *
1227                  * actually this is a bug in this function here.  we should
1228                  * be mindful of the maximum number of retries specified
1229                  * and not get stuck in a loop.
1230                  */
1231         case DID_SOFT_ERROR:
1232                 goto maybe_retry;
1233         case DID_IMM_RETRY:
1234                 return NEEDS_RETRY;
1235
1236         case DID_REQUEUE:
1237                 return ADD_TO_MLQUEUE;
1238
1239         case DID_ERROR:
1240                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1241                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1242                         /*
1243                          * execute reservation conflict processing code
1244                          * lower down
1245                          */
1246                         break;
1247                 /* fallthrough */
1248
1249         case DID_BUS_BUSY:
1250         case DID_PARITY:
1251                 goto maybe_retry;
1252         case DID_TIME_OUT:
1253                 /*
1254                  * when we scan the bus, we get timeout messages for
1255                  * these commands if there is no device available.
1256                  * other hosts report did_no_connect for the same thing.
1257                  */
1258                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1259                      scmd->cmnd[0] == INQUIRY)) {
1260                         return SUCCESS;
1261                 } else {
1262                         return FAILED;
1263                 }
1264         case DID_RESET:
1265                 return SUCCESS;
1266         default:
1267                 return FAILED;
1268         }
1269
1270         /*
1271          * next, check the message byte.
1272          */
1273         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1274                 return FAILED;
1275
1276         /*
1277          * check the status byte to see if this indicates anything special.
1278          */
1279         switch (status_byte(scmd->result)) {
1280         case QUEUE_FULL:
1281                 /*
1282                  * the case of trying to send too many commands to a
1283                  * tagged queueing device.
1284                  */
1285         case BUSY:
1286                 /*
1287                  * device can't talk to us at the moment.  Should only
1288                  * occur (SAM-3) when the task queue is empty, so will cause
1289                  * the empty queue handling to trigger a stall in the
1290                  * device.
1291                  */
1292                 return ADD_TO_MLQUEUE;
1293         case GOOD:
1294         case COMMAND_TERMINATED:
1295         case TASK_ABORTED:
1296                 return SUCCESS;
1297         case CHECK_CONDITION:
1298                 rtn = scsi_check_sense(scmd);
1299                 if (rtn == NEEDS_RETRY)
1300                         goto maybe_retry;
1301                 /* if rtn == FAILED, we have no sense information;
1302                  * returning FAILED will wake the error handler thread
1303                  * to collect the sense and redo the decide
1304                  * disposition */
1305                 return rtn;
1306         case CONDITION_GOOD:
1307         case INTERMEDIATE_GOOD:
1308         case INTERMEDIATE_C_GOOD:
1309         case ACA_ACTIVE:
1310                 /*
1311                  * who knows?  FIXME(eric)
1312                  */
1313                 return SUCCESS;
1314
1315         case RESERVATION_CONFLICT:
1316                 sdev_printk(KERN_INFO, scmd->device,
1317                             "reservation conflict\n");
1318                 return SUCCESS; /* causes immediate i/o error */
1319         default:
1320                 return FAILED;
1321         }
1322         return FAILED;
1323
1324       maybe_retry:
1325
1326         /* we requeue for retry because the error was retryable, and
1327          * the request was not marked fast fail.  Note that above,
1328          * even if the request is marked fast fail, we still requeue
1329          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1330         if ((++scmd->retries) <= scmd->allowed
1331             && !blk_noretry_request(scmd->request)) {
1332                 return NEEDS_RETRY;
1333         } else {
1334                 /*
1335                  * no more retries - report this one back to upper level.
1336                  */
1337                 return SUCCESS;
1338         }
1339 }
1340
1341 /**
1342  * scsi_eh_lock_door - Prevent medium removal for the specified device
1343  * @sdev:       SCSI device to prevent medium removal
1344  *
1345  * Locking:
1346  *      We must be called from process context; scsi_allocate_request()
1347  *      may sleep.
1348  *
1349  * Notes:
1350  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1351  *      head of the devices request queue, and continue.
1352  *
1353  * Bugs:
1354  *      scsi_allocate_request() may sleep waiting for existing requests to
1355  *      be processed.  However, since we haven't kicked off any request
1356  *      processing for this host, this may deadlock.
1357  *
1358  *      If scsi_allocate_request() fails for what ever reason, we
1359  *      completely forget to lock the door.
1360  **/
1361 static void scsi_eh_lock_door(struct scsi_device *sdev)
1362 {
1363         unsigned char cmnd[MAX_COMMAND_SIZE];
1364
1365         cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1366         cmnd[1] = 0;
1367         cmnd[2] = 0;
1368         cmnd[3] = 0;
1369         cmnd[4] = SCSI_REMOVAL_PREVENT;
1370         cmnd[5] = 0;
1371
1372         scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1373                            5, NULL, NULL, GFP_KERNEL);
1374 }
1375
1376
1377 /**
1378  * scsi_restart_operations - restart io operations to the specified host.
1379  * @shost:      Host we are restarting.
1380  *
1381  * Notes:
1382  *    When we entered the error handler, we blocked all further i/o to
1383  *    this device.  we need to 'reverse' this process.
1384  **/
1385 static void scsi_restart_operations(struct Scsi_Host *shost)
1386 {
1387         struct scsi_device *sdev;
1388         unsigned long flags;
1389
1390         /*
1391          * If the door was locked, we need to insert a door lock request
1392          * onto the head of the SCSI request queue for the device.  There
1393          * is no point trying to lock the door of an off-line device.
1394          */
1395         shost_for_each_device(sdev, shost) {
1396                 if (scsi_device_online(sdev) && sdev->locked)
1397                         scsi_eh_lock_door(sdev);
1398         }
1399
1400         /*
1401          * next free up anything directly waiting upon the host.  this
1402          * will be requests for character device operations, and also for
1403          * ioctls to queued block devices.
1404          */
1405         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1406                                           __FUNCTION__));
1407
1408         spin_lock_irqsave(shost->host_lock, flags);
1409         if (scsi_host_set_state(shost, SHOST_RUNNING))
1410                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1411                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1412         spin_unlock_irqrestore(shost->host_lock, flags);
1413
1414         wake_up(&shost->host_wait);
1415
1416         /*
1417          * finally we need to re-initiate requests that may be pending.  we will
1418          * have had everything blocked while error handling is taking place, and
1419          * now that error recovery is done, we will need to ensure that these
1420          * requests are started.
1421          */
1422         scsi_run_host_queues(shost);
1423 }
1424
1425 /**
1426  * scsi_eh_ready_devs - check device ready state and recover if not.
1427  * @shost:      host to be recovered.
1428  * @eh_done_q:  list_head for processed commands.
1429  *
1430  **/
1431 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1432                                struct list_head *work_q,
1433                                struct list_head *done_q)
1434 {
1435         if (!scsi_eh_stu(shost, work_q, done_q))
1436                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1437                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1438                                 if (!scsi_eh_host_reset(work_q, done_q))
1439                                         scsi_eh_offline_sdevs(work_q, done_q);
1440 }
1441
1442 /**
1443  * scsi_eh_flush_done_q - finish processed commands or retry them.
1444  * @done_q:     list_head of processed commands.
1445  *
1446  **/
1447 void scsi_eh_flush_done_q(struct list_head *done_q)
1448 {
1449         struct scsi_cmnd *scmd, *next;
1450
1451         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1452                 list_del_init(&scmd->eh_entry);
1453                 if (scsi_device_online(scmd->device) &&
1454                     !blk_noretry_request(scmd->request) &&
1455                     (++scmd->retries <= scmd->allowed)) {
1456                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1457                                                           " retry cmd: %p\n",
1458                                                           current->comm,
1459                                                           scmd));
1460                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1461                 } else {
1462                         /*
1463                          * If just we got sense for the device (called
1464                          * scsi_eh_get_sense), scmd->result is already
1465                          * set, do not set DRIVER_TIMEOUT.
1466                          */
1467                         if (!scmd->result)
1468                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1469                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1470                                                         " cmd: %p\n",
1471                                                         current->comm, scmd));
1472                         scsi_finish_command(scmd);
1473                 }
1474         }
1475 }
1476 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1477
1478 /**
1479  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1480  * @shost:      Host to unjam.
1481  *
1482  * Notes:
1483  *    When we come in here, we *know* that all commands on the bus have
1484  *    either completed, failed or timed out.  we also know that no further
1485  *    commands are being sent to the host, so things are relatively quiet
1486  *    and we have freedom to fiddle with things as we wish.
1487  *
1488  *    This is only the *default* implementation.  it is possible for
1489  *    individual drivers to supply their own version of this function, and
1490  *    if the maintainer wishes to do this, it is strongly suggested that
1491  *    this function be taken as a template and modified.  this function
1492  *    was designed to correctly handle problems for about 95% of the
1493  *    different cases out there, and it should always provide at least a
1494  *    reasonable amount of error recovery.
1495  *
1496  *    Any command marked 'failed' or 'timeout' must eventually have
1497  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1498  *    here, so when we restart the host after we return it should have an
1499  *    empty queue.
1500  **/
1501 static void scsi_unjam_host(struct Scsi_Host *shost)
1502 {
1503         unsigned long flags;
1504         LIST_HEAD(eh_work_q);
1505         LIST_HEAD(eh_done_q);
1506
1507         spin_lock_irqsave(shost->host_lock, flags);
1508         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1509         spin_unlock_irqrestore(shost->host_lock, flags);
1510
1511         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1512
1513         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1514                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1515                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1516
1517         scsi_eh_flush_done_q(&eh_done_q);
1518 }
1519
1520 /**
1521  * scsi_error_handler - SCSI error handler thread
1522  * @data:       Host for which we are running.
1523  *
1524  * Notes:
1525  *    This is the main error handling loop.  This is run as a kernel thread
1526  *    for every SCSI host and handles all error handling activity.
1527  **/
1528 int scsi_error_handler(void *data)
1529 {
1530         struct Scsi_Host *shost = data;
1531
1532         current->flags |= PF_NOFREEZE;
1533
1534         /*
1535          * We use TASK_INTERRUPTIBLE so that the thread is not
1536          * counted against the load average as a running process.
1537          * We never actually get interrupted because kthread_run
1538          * disables singal delivery for the created thread.
1539          */
1540         set_current_state(TASK_INTERRUPTIBLE);
1541         while (!kthread_should_stop()) {
1542                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1543                     shost->host_failed != shost->host_busy) {
1544                         SCSI_LOG_ERROR_RECOVERY(1,
1545                                 printk("Error handler scsi_eh_%d sleeping\n",
1546                                         shost->host_no));
1547                         schedule();
1548                         set_current_state(TASK_INTERRUPTIBLE);
1549                         continue;
1550                 }
1551
1552                 __set_current_state(TASK_RUNNING);
1553                 SCSI_LOG_ERROR_RECOVERY(1,
1554                         printk("Error handler scsi_eh_%d waking up\n",
1555                                 shost->host_no));
1556
1557                 /*
1558                  * We have a host that is failing for some reason.  Figure out
1559                  * what we need to do to get it up and online again (if we can).
1560                  * If we fail, we end up taking the thing offline.
1561                  */
1562                 if (shost->transportt->eh_strategy_handler)
1563                         shost->transportt->eh_strategy_handler(shost);
1564                 else
1565                         scsi_unjam_host(shost);
1566
1567                 /*
1568                  * Note - if the above fails completely, the action is to take
1569                  * individual devices offline and flush the queue of any
1570                  * outstanding requests that may have been pending.  When we
1571                  * restart, we restart any I/O to any other devices on the bus
1572                  * which are still online.
1573                  */
1574                 scsi_restart_operations(shost);
1575                 set_current_state(TASK_INTERRUPTIBLE);
1576         }
1577         __set_current_state(TASK_RUNNING);
1578
1579         SCSI_LOG_ERROR_RECOVERY(1,
1580                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1581         shost->ehandler = NULL;
1582         return 0;
1583 }
1584
1585 /*
1586  * Function:    scsi_report_bus_reset()
1587  *
1588  * Purpose:     Utility function used by low-level drivers to report that
1589  *              they have observed a bus reset on the bus being handled.
1590  *
1591  * Arguments:   shost       - Host in question
1592  *              channel     - channel on which reset was observed.
1593  *
1594  * Returns:     Nothing
1595  *
1596  * Lock status: Host lock must be held.
1597  *
1598  * Notes:       This only needs to be called if the reset is one which
1599  *              originates from an unknown location.  Resets originated
1600  *              by the mid-level itself don't need to call this, but there
1601  *              should be no harm.
1602  *
1603  *              The main purpose of this is to make sure that a CHECK_CONDITION
1604  *              is properly treated.
1605  */
1606 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1607 {
1608         struct scsi_device *sdev;
1609
1610         __shost_for_each_device(sdev, shost) {
1611                 if (channel == sdev_channel(sdev)) {
1612                         sdev->was_reset = 1;
1613                         sdev->expecting_cc_ua = 1;
1614                 }
1615         }
1616 }
1617 EXPORT_SYMBOL(scsi_report_bus_reset);
1618
1619 /*
1620  * Function:    scsi_report_device_reset()
1621  *
1622  * Purpose:     Utility function used by low-level drivers to report that
1623  *              they have observed a device reset on the device being handled.
1624  *
1625  * Arguments:   shost       - Host in question
1626  *              channel     - channel on which reset was observed
1627  *              target      - target on which reset was observed
1628  *
1629  * Returns:     Nothing
1630  *
1631  * Lock status: Host lock must be held
1632  *
1633  * Notes:       This only needs to be called if the reset is one which
1634  *              originates from an unknown location.  Resets originated
1635  *              by the mid-level itself don't need to call this, but there
1636  *              should be no harm.
1637  *
1638  *              The main purpose of this is to make sure that a CHECK_CONDITION
1639  *              is properly treated.
1640  */
1641 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1642 {
1643         struct scsi_device *sdev;
1644
1645         __shost_for_each_device(sdev, shost) {
1646                 if (channel == sdev_channel(sdev) &&
1647                     target == sdev_id(sdev)) {
1648                         sdev->was_reset = 1;
1649                         sdev->expecting_cc_ua = 1;
1650                 }
1651         }
1652 }
1653 EXPORT_SYMBOL(scsi_report_device_reset);
1654
1655 static void
1656 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1657 {
1658 }
1659
1660 /*
1661  * Function:    scsi_reset_provider
1662  *
1663  * Purpose:     Send requested reset to a bus or device at any phase.
1664  *
1665  * Arguments:   device  - device to send reset to
1666  *              flag - reset type (see scsi.h)
1667  *
1668  * Returns:     SUCCESS/FAILURE.
1669  *
1670  * Notes:       This is used by the SCSI Generic driver to provide
1671  *              Bus/Device reset capability.
1672  */
1673 int
1674 scsi_reset_provider(struct scsi_device *dev, int flag)
1675 {
1676         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1677         struct request req;
1678         int rtn;
1679
1680         scmd->request = &req;
1681         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1682         scmd->request->rq_status        = RQ_SCSI_BUSY;
1683
1684         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1685     
1686         scmd->scsi_done         = scsi_reset_provider_done_command;
1687         scmd->done                      = NULL;
1688         scmd->buffer                    = NULL;
1689         scmd->bufflen                   = 0;
1690         scmd->request_buffer            = NULL;
1691         scmd->request_bufflen           = 0;
1692
1693         scmd->cmd_len                   = 0;
1694
1695         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1696         scmd->sc_request                = NULL;
1697         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1698
1699         init_timer(&scmd->eh_timeout);
1700
1701         /*
1702          * Sometimes the command can get back into the timer chain,
1703          * so use the pid as an identifier.
1704          */
1705         scmd->pid                       = 0;
1706
1707         switch (flag) {
1708         case SCSI_TRY_RESET_DEVICE:
1709                 rtn = scsi_try_bus_device_reset(scmd);
1710                 if (rtn == SUCCESS)
1711                         break;
1712                 /* FALLTHROUGH */
1713         case SCSI_TRY_RESET_BUS:
1714                 rtn = scsi_try_bus_reset(scmd);
1715                 if (rtn == SUCCESS)
1716                         break;
1717                 /* FALLTHROUGH */
1718         case SCSI_TRY_RESET_HOST:
1719                 rtn = scsi_try_host_reset(scmd);
1720                 break;
1721         default:
1722                 rtn = FAILED;
1723         }
1724
1725         scsi_next_command(scmd);
1726         return rtn;
1727 }
1728 EXPORT_SYMBOL(scsi_reset_provider);
1729
1730 /**
1731  * scsi_normalize_sense - normalize main elements from either fixed or
1732  *                      descriptor sense data format into a common format.
1733  *
1734  * @sense_buffer:       byte array containing sense data returned by device
1735  * @sb_len:             number of valid bytes in sense_buffer
1736  * @sshdr:              pointer to instance of structure that common
1737  *                      elements are written to.
1738  *
1739  * Notes:
1740  *      The "main elements" from sense data are: response_code, sense_key,
1741  *      asc, ascq and additional_length (only for descriptor format).
1742  *
1743  *      Typically this function can be called after a device has
1744  *      responded to a SCSI command with the CHECK_CONDITION status.
1745  *
1746  * Return value:
1747  *      1 if valid sense data information found, else 0;
1748  **/
1749 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1750                          struct scsi_sense_hdr *sshdr)
1751 {
1752         if (!sense_buffer || !sb_len)
1753                 return 0;
1754
1755         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1756
1757         sshdr->response_code = (sense_buffer[0] & 0x7f);
1758
1759         if (!scsi_sense_valid(sshdr))
1760                 return 0;
1761
1762         if (sshdr->response_code >= 0x72) {
1763                 /*
1764                  * descriptor format
1765                  */
1766                 if (sb_len > 1)
1767                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1768                 if (sb_len > 2)
1769                         sshdr->asc = sense_buffer[2];
1770                 if (sb_len > 3)
1771                         sshdr->ascq = sense_buffer[3];
1772                 if (sb_len > 7)
1773                         sshdr->additional_length = sense_buffer[7];
1774         } else {
1775                 /* 
1776                  * fixed format
1777                  */
1778                 if (sb_len > 2)
1779                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1780                 if (sb_len > 7) {
1781                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1782                                          sb_len : (sense_buffer[7] + 8);
1783                         if (sb_len > 12)
1784                                 sshdr->asc = sense_buffer[12];
1785                         if (sb_len > 13)
1786                                 sshdr->ascq = sense_buffer[13];
1787                 }
1788         }
1789
1790         return 1;
1791 }
1792 EXPORT_SYMBOL(scsi_normalize_sense);
1793
1794 int scsi_request_normalize_sense(struct scsi_request *sreq,
1795                                  struct scsi_sense_hdr *sshdr)
1796 {
1797         return scsi_normalize_sense(sreq->sr_sense_buffer,
1798                         sizeof(sreq->sr_sense_buffer), sshdr);
1799 }
1800 EXPORT_SYMBOL(scsi_request_normalize_sense);
1801
1802 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1803                                  struct scsi_sense_hdr *sshdr)
1804 {
1805         return scsi_normalize_sense(cmd->sense_buffer,
1806                         sizeof(cmd->sense_buffer), sshdr);
1807 }
1808 EXPORT_SYMBOL(scsi_command_normalize_sense);
1809
1810 /**
1811  * scsi_sense_desc_find - search for a given descriptor type in
1812  *                      descriptor sense data format.
1813  *
1814  * @sense_buffer:       byte array of descriptor format sense data
1815  * @sb_len:             number of valid bytes in sense_buffer
1816  * @desc_type:          value of descriptor type to find
1817  *                      (e.g. 0 -> information)
1818  *
1819  * Notes:
1820  *      only valid when sense data is in descriptor format
1821  *
1822  * Return value:
1823  *      pointer to start of (first) descriptor if found else NULL
1824  **/
1825 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1826                                 int desc_type)
1827 {
1828         int add_sen_len, add_len, desc_len, k;
1829         const u8 * descp;
1830
1831         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1832                 return NULL;
1833         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1834                 return NULL;
1835         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1836                         add_sen_len : (sb_len - 8);
1837         descp = &sense_buffer[8];
1838         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1839                 descp += desc_len;
1840                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1841                 desc_len = add_len + 2;
1842                 if (descp[0] == desc_type)
1843                         return descp;
1844                 if (add_len < 0) // short descriptor ??
1845                         break;
1846         }
1847         return NULL;
1848 }
1849 EXPORT_SYMBOL(scsi_sense_desc_find);
1850
1851 /**
1852  * scsi_get_sense_info_fld - attempts to get information field from
1853  *                      sense data (either fixed or descriptor format)
1854  *
1855  * @sense_buffer:       byte array of sense data
1856  * @sb_len:             number of valid bytes in sense_buffer
1857  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1858  *                      field will be placed if found.
1859  *
1860  * Return value:
1861  *      1 if information field found, 0 if not found.
1862  **/
1863 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1864                             u64 * info_out)
1865 {
1866         int j;
1867         const u8 * ucp;
1868         u64 ull;
1869
1870         if (sb_len < 7)
1871                 return 0;
1872         switch (sense_buffer[0] & 0x7f) {
1873         case 0x70:
1874         case 0x71:
1875                 if (sense_buffer[0] & 0x80) {
1876                         *info_out = (sense_buffer[3] << 24) +
1877                                     (sense_buffer[4] << 16) +
1878                                     (sense_buffer[5] << 8) + sense_buffer[6];
1879                         return 1;
1880                 } else
1881                         return 0;
1882         case 0x72:
1883         case 0x73:
1884                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1885                                            0 /* info desc */);
1886                 if (ucp && (0xa == ucp[1])) {
1887                         ull = 0;
1888                         for (j = 0; j < 8; ++j) {
1889                                 if (j > 0)
1890                                         ull <<= 8;
1891                                 ull |= ucp[4 + j];
1892                         }
1893                         *info_out = ull;
1894                         return 1;
1895                 } else
1896                         return 0;
1897         default:
1898                 return 0;
1899         }
1900 }
1901 EXPORT_SYMBOL(scsi_get_sense_info_fld);