Merge branch 'master' into upstream
[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_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_eh.h>
33 #include <scsi/scsi_transport.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_ioctl.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
478         spin_lock_irqsave(shost->host_lock, flags);
479         scsi_log_send(scmd);
480         shost->hostt->queuecommand(scmd, scsi_eh_done);
481         spin_unlock_irqrestore(shost->host_lock, flags);
482
483         timeleft = wait_for_completion_timeout(&done, timeout);
484
485         shost->eh_action = NULL;
486
487         scsi_log_completion(scmd, SUCCESS);
488
489         SCSI_LOG_ERROR_RECOVERY(3,
490                 printk("%s: scmd: %p, timeleft: %ld\n",
491                         __FUNCTION__, scmd, timeleft));
492
493         /*
494          * If there is time left scsi_eh_done got called, and we will
495          * examine the actual status codes to see whether the command
496          * actually did complete normally, else tell the host to forget
497          * about this command.
498          */
499         if (timeleft) {
500                 rtn = scsi_eh_completed_normally(scmd);
501                 SCSI_LOG_ERROR_RECOVERY(3,
502                         printk("%s: scsi_eh_completed_normally %x\n",
503                                __FUNCTION__, rtn));
504
505                 switch (rtn) {
506                 case SUCCESS:
507                 case NEEDS_RETRY:
508                 case FAILED:
509                         break;
510                 default:
511                         rtn = FAILED;
512                         break;
513                 }
514         } else {
515                 /*
516                  * FIXME(eric) - we are not tracking whether we could
517                  * abort a timed out command or not.  not sure how
518                  * we should treat them differently anyways.
519                  */
520                 if (shost->hostt->eh_abort_handler)
521                         shost->hostt->eh_abort_handler(scmd);
522                 rtn = FAILED;
523         }
524
525         return rtn;
526 }
527
528 /**
529  * scsi_request_sense - Request sense data from a particular target.
530  * @scmd:       SCSI cmd for request sense.
531  *
532  * Notes:
533  *    Some hosts automatically obtain this information, others require
534  *    that we obtain it on our own. This function will *not* return until
535  *    the command either times out, or it completes.
536  **/
537 static int scsi_request_sense(struct scsi_cmnd *scmd)
538 {
539         static unsigned char generic_sense[6] =
540         {REQUEST_SENSE, 0, 0, 0, 252, 0};
541         unsigned char *scsi_result;
542         int saved_result;
543         int rtn;
544
545         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
546
547         scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
548
549
550         if (unlikely(!scsi_result)) {
551                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
552                        __FUNCTION__);
553                 return FAILED;
554         }
555
556         /*
557          * zero the sense buffer.  some host adapters automatically always
558          * request sense, so it is not a good idea that
559          * scmd->request_buffer and scmd->sense_buffer point to the same
560          * address (db).  0 is not a valid sense code. 
561          */
562         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
563         memset(scsi_result, 0, 252);
564
565         saved_result = scmd->result;
566         scmd->request_buffer = scsi_result;
567         scmd->request_bufflen = 252;
568         scmd->use_sg = 0;
569         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
570         scmd->sc_data_direction = DMA_FROM_DEVICE;
571         scmd->underflow = 0;
572
573         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
574
575         /* last chance to have valid sense data */
576         if(!SCSI_SENSE_VALID(scmd)) {
577                 memcpy(scmd->sense_buffer, scmd->request_buffer,
578                        sizeof(scmd->sense_buffer));
579         }
580
581         kfree(scsi_result);
582
583         /*
584          * when we eventually call scsi_finish, we really wish to complete
585          * the original request, so let's restore the original data. (db)
586          */
587         scsi_setup_cmd_retry(scmd);
588         scmd->result = saved_result;
589         return rtn;
590 }
591
592 /**
593  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
594  * @scmd:       Original SCSI cmd that eh has finished.
595  * @done_q:     Queue for processed commands.
596  *
597  * Notes:
598  *    We don't want to use the normal command completion while we are are
599  *    still handling errors - it may cause other commands to be queued,
600  *    and that would disturb what we are doing.  thus we really want to
601  *    keep a list of pending commands for final completion, and once we
602  *    are ready to leave error handling we handle completion for real.
603  **/
604 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
605 {
606         scmd->device->host->host_failed--;
607         scmd->eh_eflags = 0;
608
609         /*
610          * set this back so that the upper level can correctly free up
611          * things.
612          */
613         scsi_setup_cmd_retry(scmd);
614         list_move_tail(&scmd->eh_entry, done_q);
615 }
616 EXPORT_SYMBOL(scsi_eh_finish_cmd);
617
618 /**
619  * scsi_eh_get_sense - Get device sense data.
620  * @work_q:     Queue of commands to process.
621  * @done_q:     Queue of proccessed commands..
622  *
623  * Description:
624  *    See if we need to request sense information.  if so, then get it
625  *    now, so we have a better idea of what to do.  
626  *
627  * Notes:
628  *    This has the unfortunate side effect that if a shost adapter does
629  *    not automatically request sense information, that we end up shutting
630  *    it down before we request it.
631  *
632  *    All drivers should request sense information internally these days,
633  *    so for now all I have to say is tough noogies if you end up in here.
634  *
635  *    XXX: Long term this code should go away, but that needs an audit of
636  *         all LLDDs first.
637  **/
638 static int scsi_eh_get_sense(struct list_head *work_q,
639                              struct list_head *done_q)
640 {
641         struct scsi_cmnd *scmd, *next;
642         int rtn;
643
644         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
645                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
646                     SCSI_SENSE_VALID(scmd))
647                         continue;
648
649                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
650                                                   "%s: requesting sense\n",
651                                                   current->comm));
652                 rtn = scsi_request_sense(scmd);
653                 if (rtn != SUCCESS)
654                         continue;
655
656                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
657                                                   " result %x\n", scmd,
658                                                   scmd->result));
659                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
660
661                 rtn = scsi_decide_disposition(scmd);
662
663                 /*
664                  * if the result was normal, then just pass it along to the
665                  * upper level.
666                  */
667                 if (rtn == SUCCESS)
668                         /* we don't want this command reissued, just
669                          * finished with the sense data, so set
670                          * retries to the max allowed to ensure it
671                          * won't get reissued */
672                         scmd->retries = scmd->allowed;
673                 else if (rtn != NEEDS_RETRY)
674                         continue;
675
676                 scsi_eh_finish_cmd(scmd, done_q);
677         }
678
679         return list_empty(work_q);
680 }
681
682 /**
683  * scsi_try_to_abort_cmd - Ask host to abort a running command.
684  * @scmd:       SCSI cmd to abort from Lower Level.
685  *
686  * Notes:
687  *    This function will not return until the user's completion function
688  *    has been called.  there is no timeout on this operation.  if the
689  *    author of the low-level driver wishes this operation to be timed,
690  *    they can provide this facility themselves.  helper functions in
691  *    scsi_error.c can be supplied to make this easier to do.
692  **/
693 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
694 {
695         if (!scmd->device->host->hostt->eh_abort_handler)
696                 return FAILED;
697
698         /*
699          * scsi_done was called just after the command timed out and before
700          * we had a chance to process it. (db)
701          */
702         if (scmd->serial_number == 0)
703                 return SUCCESS;
704         return scmd->device->host->hostt->eh_abort_handler(scmd);
705 }
706
707 /**
708  * scsi_eh_tur - Send TUR to device.
709  * @scmd:       Scsi cmd to send TUR
710  *
711  * Return value:
712  *    0 - Device is ready. 1 - Device NOT ready.
713  **/
714 static int scsi_eh_tur(struct scsi_cmnd *scmd)
715 {
716         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
717         int retry_cnt = 1, rtn;
718         int saved_result;
719
720 retry_tur:
721         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
722
723         /*
724          * zero the sense buffer.  the scsi spec mandates that any
725          * untransferred sense data should be interpreted as being zero.
726          */
727         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
728
729         saved_result = scmd->result;
730         scmd->request_buffer = NULL;
731         scmd->request_bufflen = 0;
732         scmd->use_sg = 0;
733         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
734         scmd->underflow = 0;
735         scmd->sc_data_direction = DMA_NONE;
736
737         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
738
739         /*
740          * when we eventually call scsi_finish, we really wish to complete
741          * the original request, so let's restore the original data. (db)
742          */
743         scsi_setup_cmd_retry(scmd);
744         scmd->result = saved_result;
745
746         /*
747          * hey, we are done.  let's look to see what happened.
748          */
749         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
750                 __FUNCTION__, scmd, rtn));
751         if (rtn == SUCCESS)
752                 return 0;
753         else if (rtn == NEEDS_RETRY) {
754                 if (retry_cnt--)
755                         goto retry_tur;
756                 return 0;
757         }
758         return 1;
759 }
760
761 /**
762  * scsi_eh_abort_cmds - abort canceled commands.
763  * @shost:      scsi host being recovered.
764  * @eh_done_q:  list_head for processed commands.
765  *
766  * Decription:
767  *    Try and see whether or not it makes sense to try and abort the
768  *    running command.  this only works out to be the case if we have one
769  *    command that has timed out.  if the command simply failed, it makes
770  *    no sense to try and abort the command, since as far as the shost
771  *    adapter is concerned, it isn't running.
772  **/
773 static int scsi_eh_abort_cmds(struct list_head *work_q,
774                               struct list_head *done_q)
775 {
776         struct scsi_cmnd *scmd, *next;
777         int rtn;
778
779         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
780                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
781                         continue;
782                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
783                                                   "0x%p\n", current->comm,
784                                                   scmd));
785                 rtn = scsi_try_to_abort_cmd(scmd);
786                 if (rtn == SUCCESS) {
787                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
788                         if (!scsi_device_online(scmd->device) ||
789                             !scsi_eh_tur(scmd)) {
790                                 scsi_eh_finish_cmd(scmd, done_q);
791                         }
792                                 
793                 } else
794                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
795                                                           " cmd failed:"
796                                                           "0x%p\n",
797                                                           current->comm,
798                                                           scmd));
799         }
800
801         return list_empty(work_q);
802 }
803
804 /**
805  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
806  * @scmd:       SCSI cmd used to send BDR       
807  *
808  * Notes:
809  *    There is no timeout for this operation.  if this operation is
810  *    unreliable for a given host, then the host itself needs to put a
811  *    timer on it, and set the host back to a consistent state prior to
812  *    returning.
813  **/
814 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
815 {
816         int rtn;
817
818         if (!scmd->device->host->hostt->eh_device_reset_handler)
819                 return FAILED;
820
821         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
822         if (rtn == SUCCESS) {
823                 scmd->device->was_reset = 1;
824                 scmd->device->expecting_cc_ua = 1;
825         }
826
827         return rtn;
828 }
829
830 /**
831  * scsi_eh_try_stu - Send START_UNIT to device.
832  * @scmd:       Scsi cmd to send START_UNIT
833  *
834  * Return value:
835  *    0 - Device is ready. 1 - Device NOT ready.
836  **/
837 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
838 {
839         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
840         int rtn;
841         int saved_result;
842
843         if (!scmd->device->allow_restart)
844                 return 1;
845
846         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
847
848         /*
849          * zero the sense buffer.  the scsi spec mandates that any
850          * untransferred sense data should be interpreted as being zero.
851          */
852         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
853
854         saved_result = scmd->result;
855         scmd->request_buffer = NULL;
856         scmd->request_bufflen = 0;
857         scmd->use_sg = 0;
858         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
859         scmd->underflow = 0;
860         scmd->sc_data_direction = DMA_NONE;
861
862         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
863
864         /*
865          * when we eventually call scsi_finish, we really wish to complete
866          * the original request, so let's restore the original data. (db)
867          */
868         scsi_setup_cmd_retry(scmd);
869         scmd->result = saved_result;
870
871         /*
872          * hey, we are done.  let's look to see what happened.
873          */
874         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
875                 __FUNCTION__, scmd, rtn));
876         if (rtn == SUCCESS)
877                 return 0;
878         return 1;
879 }
880
881  /**
882  * scsi_eh_stu - send START_UNIT if needed
883  * @shost:      scsi host being recovered.
884  * @eh_done_q:  list_head for processed commands.
885  *
886  * Notes:
887  *    If commands are failing due to not ready, initializing command required,
888  *      try revalidating the device, which will end up sending a start unit. 
889  **/
890 static int scsi_eh_stu(struct Scsi_Host *shost,
891                               struct list_head *work_q,
892                               struct list_head *done_q)
893 {
894         struct scsi_cmnd *scmd, *stu_scmd, *next;
895         struct scsi_device *sdev;
896
897         shost_for_each_device(sdev, shost) {
898                 stu_scmd = NULL;
899                 list_for_each_entry(scmd, work_q, eh_entry)
900                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
901                             scsi_check_sense(scmd) == FAILED ) {
902                                 stu_scmd = scmd;
903                                 break;
904                         }
905
906                 if (!stu_scmd)
907                         continue;
908
909                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
910                                                   " 0x%p\n", current->comm, sdev));
911
912                 if (!scsi_eh_try_stu(stu_scmd)) {
913                         if (!scsi_device_online(sdev) ||
914                             !scsi_eh_tur(stu_scmd)) {
915                                 list_for_each_entry_safe(scmd, next,
916                                                           work_q, eh_entry) {
917                                         if (scmd->device == sdev)
918                                                 scsi_eh_finish_cmd(scmd, done_q);
919                                 }
920                         }
921                 } else {
922                         SCSI_LOG_ERROR_RECOVERY(3,
923                                                 printk("%s: START_UNIT failed to sdev:"
924                                                        " 0x%p\n", current->comm, sdev));
925                 }
926         }
927
928         return list_empty(work_q);
929 }
930
931
932 /**
933  * scsi_eh_bus_device_reset - send bdr if needed
934  * @shost:      scsi host being recovered.
935  * @eh_done_q:  list_head for processed commands.
936  *
937  * Notes:
938  *    Try a bus device reset.  still, look to see whether we have multiple
939  *    devices that are jammed or not - if we have multiple devices, it
940  *    makes no sense to try bus_device_reset - we really would need to try
941  *    a bus_reset instead. 
942  **/
943 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
944                                     struct list_head *work_q,
945                                     struct list_head *done_q)
946 {
947         struct scsi_cmnd *scmd, *bdr_scmd, *next;
948         struct scsi_device *sdev;
949         int rtn;
950
951         shost_for_each_device(sdev, shost) {
952                 bdr_scmd = NULL;
953                 list_for_each_entry(scmd, work_q, eh_entry)
954                         if (scmd->device == sdev) {
955                                 bdr_scmd = scmd;
956                                 break;
957                         }
958
959                 if (!bdr_scmd)
960                         continue;
961
962                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
963                                                   " 0x%p\n", current->comm,
964                                                   sdev));
965                 rtn = scsi_try_bus_device_reset(bdr_scmd);
966                 if (rtn == SUCCESS) {
967                         if (!scsi_device_online(sdev) ||
968                             !scsi_eh_tur(bdr_scmd)) {
969                                 list_for_each_entry_safe(scmd, next,
970                                                          work_q, eh_entry) {
971                                         if (scmd->device == sdev)
972                                                 scsi_eh_finish_cmd(scmd,
973                                                                    done_q);
974                                 }
975                         }
976                 } else {
977                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
978                                                           " failed sdev:"
979                                                           "0x%p\n",
980                                                           current->comm,
981                                                            sdev));
982                 }
983         }
984
985         return list_empty(work_q);
986 }
987
988 /**
989  * scsi_try_bus_reset - ask host to perform a bus reset
990  * @scmd:       SCSI cmd to send bus reset.
991  **/
992 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
993 {
994         unsigned long flags;
995         int rtn;
996
997         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
998                                           __FUNCTION__));
999
1000         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1001                 return FAILED;
1002
1003         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1004
1005         if (rtn == SUCCESS) {
1006                 if (!scmd->device->host->hostt->skip_settle_delay)
1007                         ssleep(BUS_RESET_SETTLE_TIME);
1008                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1009                 scsi_report_bus_reset(scmd->device->host,
1010                                       scmd_channel(scmd));
1011                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1012         }
1013
1014         return rtn;
1015 }
1016
1017 /**
1018  * scsi_try_host_reset - ask host adapter to reset itself
1019  * @scmd:       SCSI cmd to send hsot reset.
1020  **/
1021 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1022 {
1023         unsigned long flags;
1024         int rtn;
1025
1026         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1027                                           __FUNCTION__));
1028
1029         if (!scmd->device->host->hostt->eh_host_reset_handler)
1030                 return FAILED;
1031
1032         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1033
1034         if (rtn == SUCCESS) {
1035                 if (!scmd->device->host->hostt->skip_settle_delay)
1036                         ssleep(HOST_RESET_SETTLE_TIME);
1037                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1038                 scsi_report_bus_reset(scmd->device->host,
1039                                       scmd_channel(scmd));
1040                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1041         }
1042
1043         return rtn;
1044 }
1045
1046 /**
1047  * scsi_eh_bus_reset - send a bus reset 
1048  * @shost:      scsi host being recovered.
1049  * @eh_done_q:  list_head for processed commands.
1050  **/
1051 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1052                              struct list_head *work_q,
1053                              struct list_head *done_q)
1054 {
1055         struct scsi_cmnd *scmd, *chan_scmd, *next;
1056         unsigned int channel;
1057         int rtn;
1058
1059         /*
1060          * we really want to loop over the various channels, and do this on
1061          * a channel by channel basis.  we should also check to see if any
1062          * of the failed commands are on soft_reset devices, and if so, skip
1063          * the reset.  
1064          */
1065
1066         for (channel = 0; channel <= shost->max_channel; channel++) {
1067                 chan_scmd = NULL;
1068                 list_for_each_entry(scmd, work_q, eh_entry) {
1069                         if (channel == scmd_channel(scmd)) {
1070                                 chan_scmd = scmd;
1071                                 break;
1072                                 /*
1073                                  * FIXME add back in some support for
1074                                  * soft_reset devices.
1075                                  */
1076                         }
1077                 }
1078
1079                 if (!chan_scmd)
1080                         continue;
1081                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1082                                                   " %d\n", current->comm,
1083                                                   channel));
1084                 rtn = scsi_try_bus_reset(chan_scmd);
1085                 if (rtn == SUCCESS) {
1086                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1087                                 if (channel == scmd_channel(scmd))
1088                                         if (!scsi_device_online(scmd->device) ||
1089                                             !scsi_eh_tur(scmd))
1090                                                 scsi_eh_finish_cmd(scmd,
1091                                                                    done_q);
1092                         }
1093                 } else {
1094                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1095                                                           " failed chan: %d\n",
1096                                                           current->comm,
1097                                                           channel));
1098                 }
1099         }
1100         return list_empty(work_q);
1101 }
1102
1103 /**
1104  * scsi_eh_host_reset - send a host reset 
1105  * @work_q:     list_head for processed commands.
1106  * @done_q:     list_head for processed commands.
1107  **/
1108 static int scsi_eh_host_reset(struct list_head *work_q,
1109                               struct list_head *done_q)
1110 {
1111         struct scsi_cmnd *scmd, *next;
1112         int rtn;
1113
1114         if (!list_empty(work_q)) {
1115                 scmd = list_entry(work_q->next,
1116                                   struct scsi_cmnd, eh_entry);
1117
1118                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1119                                                   , current->comm));
1120
1121                 rtn = scsi_try_host_reset(scmd);
1122                 if (rtn == SUCCESS) {
1123                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1124                                 if (!scsi_device_online(scmd->device) ||
1125                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1126                                     !scsi_eh_tur(scmd))
1127                                         scsi_eh_finish_cmd(scmd, done_q);
1128                         }
1129                 } else {
1130                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1131                                                           " failed\n",
1132                                                           current->comm));
1133                 }
1134         }
1135         return list_empty(work_q);
1136 }
1137
1138 /**
1139  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1140  * @work_q:     list_head for processed commands.
1141  * @done_q:     list_head for processed commands.
1142  *
1143  **/
1144 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1145                                   struct list_head *done_q)
1146 {
1147         struct scsi_cmnd *scmd, *next;
1148
1149         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1150                 sdev_printk(KERN_INFO, scmd->device,
1151                             "scsi: Device offlined - not"
1152                             " ready after error recovery\n");
1153                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1154                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1155                         /*
1156                          * FIXME: Handle lost cmds.
1157                          */
1158                 }
1159                 scsi_eh_finish_cmd(scmd, done_q);
1160         }
1161         return;
1162 }
1163
1164 /**
1165  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1166  * @scmd:       SCSI cmd to examine.
1167  *
1168  * Notes:
1169  *    This is *only* called when we are examining the status after sending
1170  *    out the actual data command.  any commands that are queued for error
1171  *    recovery (e.g. test_unit_ready) do *not* come through here.
1172  *
1173  *    When this routine returns failed, it means the error handler thread
1174  *    is woken.  In cases where the error code indicates an error that
1175  *    doesn't require the error handler read (i.e. we don't need to
1176  *    abort/reset), this function should return SUCCESS.
1177  **/
1178 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1179 {
1180         int rtn;
1181
1182         /*
1183          * if the device is offline, then we clearly just pass the result back
1184          * up to the top level.
1185          */
1186         if (!scsi_device_online(scmd->device)) {
1187                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1188                                                   " as SUCCESS\n",
1189                                                   __FUNCTION__));
1190                 return SUCCESS;
1191         }
1192
1193         /*
1194          * first check the host byte, to see if there is anything in there
1195          * that would indicate what we need to do.
1196          */
1197         switch (host_byte(scmd->result)) {
1198         case DID_PASSTHROUGH:
1199                 /*
1200                  * no matter what, pass this through to the upper layer.
1201                  * nuke this special code so that it looks like we are saying
1202                  * did_ok.
1203                  */
1204                 scmd->result &= 0xff00ffff;
1205                 return SUCCESS;
1206         case DID_OK:
1207                 /*
1208                  * looks good.  drop through, and check the next byte.
1209                  */
1210                 break;
1211         case DID_NO_CONNECT:
1212         case DID_BAD_TARGET:
1213         case DID_ABORT:
1214                 /*
1215                  * note - this means that we just report the status back
1216                  * to the top level driver, not that we actually think
1217                  * that it indicates SUCCESS.
1218                  */
1219                 return SUCCESS;
1220                 /*
1221                  * when the low level driver returns did_soft_error,
1222                  * it is responsible for keeping an internal retry counter 
1223                  * in order to avoid endless loops (db)
1224                  *
1225                  * actually this is a bug in this function here.  we should
1226                  * be mindful of the maximum number of retries specified
1227                  * and not get stuck in a loop.
1228                  */
1229         case DID_SOFT_ERROR:
1230                 goto maybe_retry;
1231         case DID_IMM_RETRY:
1232                 return NEEDS_RETRY;
1233
1234         case DID_REQUEUE:
1235                 return ADD_TO_MLQUEUE;
1236
1237         case DID_ERROR:
1238                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1239                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1240                         /*
1241                          * execute reservation conflict processing code
1242                          * lower down
1243                          */
1244                         break;
1245                 /* fallthrough */
1246
1247         case DID_BUS_BUSY:
1248         case DID_PARITY:
1249                 goto maybe_retry;
1250         case DID_TIME_OUT:
1251                 /*
1252                  * when we scan the bus, we get timeout messages for
1253                  * these commands if there is no device available.
1254                  * other hosts report did_no_connect for the same thing.
1255                  */
1256                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1257                      scmd->cmnd[0] == INQUIRY)) {
1258                         return SUCCESS;
1259                 } else {
1260                         return FAILED;
1261                 }
1262         case DID_RESET:
1263                 return SUCCESS;
1264         default:
1265                 return FAILED;
1266         }
1267
1268         /*
1269          * next, check the message byte.
1270          */
1271         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1272                 return FAILED;
1273
1274         /*
1275          * check the status byte to see if this indicates anything special.
1276          */
1277         switch (status_byte(scmd->result)) {
1278         case QUEUE_FULL:
1279                 /*
1280                  * the case of trying to send too many commands to a
1281                  * tagged queueing device.
1282                  */
1283         case BUSY:
1284                 /*
1285                  * device can't talk to us at the moment.  Should only
1286                  * occur (SAM-3) when the task queue is empty, so will cause
1287                  * the empty queue handling to trigger a stall in the
1288                  * device.
1289                  */
1290                 return ADD_TO_MLQUEUE;
1291         case GOOD:
1292         case COMMAND_TERMINATED:
1293         case TASK_ABORTED:
1294                 return SUCCESS;
1295         case CHECK_CONDITION:
1296                 rtn = scsi_check_sense(scmd);
1297                 if (rtn == NEEDS_RETRY)
1298                         goto maybe_retry;
1299                 /* if rtn == FAILED, we have no sense information;
1300                  * returning FAILED will wake the error handler thread
1301                  * to collect the sense and redo the decide
1302                  * disposition */
1303                 return rtn;
1304         case CONDITION_GOOD:
1305         case INTERMEDIATE_GOOD:
1306         case INTERMEDIATE_C_GOOD:
1307         case ACA_ACTIVE:
1308                 /*
1309                  * who knows?  FIXME(eric)
1310                  */
1311                 return SUCCESS;
1312
1313         case RESERVATION_CONFLICT:
1314                 sdev_printk(KERN_INFO, scmd->device,
1315                             "reservation conflict\n");
1316                 return SUCCESS; /* causes immediate i/o error */
1317         default:
1318                 return FAILED;
1319         }
1320         return FAILED;
1321
1322       maybe_retry:
1323
1324         /* we requeue for retry because the error was retryable, and
1325          * the request was not marked fast fail.  Note that above,
1326          * even if the request is marked fast fail, we still requeue
1327          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1328         if ((++scmd->retries) <= scmd->allowed
1329             && !blk_noretry_request(scmd->request)) {
1330                 return NEEDS_RETRY;
1331         } else {
1332                 /*
1333                  * no more retries - report this one back to upper level.
1334                  */
1335                 return SUCCESS;
1336         }
1337 }
1338
1339 /**
1340  * scsi_eh_lock_door - Prevent medium removal for the specified device
1341  * @sdev:       SCSI device to prevent medium removal
1342  *
1343  * Locking:
1344  *      We must be called from process context; scsi_allocate_request()
1345  *      may sleep.
1346  *
1347  * Notes:
1348  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1349  *      head of the devices request queue, and continue.
1350  *
1351  * Bugs:
1352  *      scsi_allocate_request() may sleep waiting for existing requests to
1353  *      be processed.  However, since we haven't kicked off any request
1354  *      processing for this host, this may deadlock.
1355  *
1356  *      If scsi_allocate_request() fails for what ever reason, we
1357  *      completely forget to lock the door.
1358  **/
1359 static void scsi_eh_lock_door(struct scsi_device *sdev)
1360 {
1361         unsigned char cmnd[MAX_COMMAND_SIZE];
1362
1363         cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1364         cmnd[1] = 0;
1365         cmnd[2] = 0;
1366         cmnd[3] = 0;
1367         cmnd[4] = SCSI_REMOVAL_PREVENT;
1368         cmnd[5] = 0;
1369
1370         scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1371                            5, NULL, NULL, GFP_KERNEL);
1372 }
1373
1374
1375 /**
1376  * scsi_restart_operations - restart io operations to the specified host.
1377  * @shost:      Host we are restarting.
1378  *
1379  * Notes:
1380  *    When we entered the error handler, we blocked all further i/o to
1381  *    this device.  we need to 'reverse' this process.
1382  **/
1383 static void scsi_restart_operations(struct Scsi_Host *shost)
1384 {
1385         struct scsi_device *sdev;
1386         unsigned long flags;
1387
1388         /*
1389          * If the door was locked, we need to insert a door lock request
1390          * onto the head of the SCSI request queue for the device.  There
1391          * is no point trying to lock the door of an off-line device.
1392          */
1393         shost_for_each_device(sdev, shost) {
1394                 if (scsi_device_online(sdev) && sdev->locked)
1395                         scsi_eh_lock_door(sdev);
1396         }
1397
1398         /*
1399          * next free up anything directly waiting upon the host.  this
1400          * will be requests for character device operations, and also for
1401          * ioctls to queued block devices.
1402          */
1403         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1404                                           __FUNCTION__));
1405
1406         spin_lock_irqsave(shost->host_lock, flags);
1407         if (scsi_host_set_state(shost, SHOST_RUNNING))
1408                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1409                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1410         spin_unlock_irqrestore(shost->host_lock, flags);
1411
1412         wake_up(&shost->host_wait);
1413
1414         /*
1415          * finally we need to re-initiate requests that may be pending.  we will
1416          * have had everything blocked while error handling is taking place, and
1417          * now that error recovery is done, we will need to ensure that these
1418          * requests are started.
1419          */
1420         scsi_run_host_queues(shost);
1421 }
1422
1423 /**
1424  * scsi_eh_ready_devs - check device ready state and recover if not.
1425  * @shost:      host to be recovered.
1426  * @eh_done_q:  list_head for processed commands.
1427  *
1428  **/
1429 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1430                                struct list_head *work_q,
1431                                struct list_head *done_q)
1432 {
1433         if (!scsi_eh_stu(shost, work_q, done_q))
1434                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1435                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1436                                 if (!scsi_eh_host_reset(work_q, done_q))
1437                                         scsi_eh_offline_sdevs(work_q, done_q);
1438 }
1439
1440 /**
1441  * scsi_eh_flush_done_q - finish processed commands or retry them.
1442  * @done_q:     list_head of processed commands.
1443  *
1444  **/
1445 void scsi_eh_flush_done_q(struct list_head *done_q)
1446 {
1447         struct scsi_cmnd *scmd, *next;
1448
1449         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1450                 list_del_init(&scmd->eh_entry);
1451                 if (scsi_device_online(scmd->device) &&
1452                     !blk_noretry_request(scmd->request) &&
1453                     (++scmd->retries <= scmd->allowed)) {
1454                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1455                                                           " retry cmd: %p\n",
1456                                                           current->comm,
1457                                                           scmd));
1458                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1459                 } else {
1460                         /*
1461                          * If just we got sense for the device (called
1462                          * scsi_eh_get_sense), scmd->result is already
1463                          * set, do not set DRIVER_TIMEOUT.
1464                          */
1465                         if (!scmd->result)
1466                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1467                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1468                                                         " cmd: %p\n",
1469                                                         current->comm, scmd));
1470                         scsi_finish_command(scmd);
1471                 }
1472         }
1473 }
1474 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1475
1476 /**
1477  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1478  * @shost:      Host to unjam.
1479  *
1480  * Notes:
1481  *    When we come in here, we *know* that all commands on the bus have
1482  *    either completed, failed or timed out.  we also know that no further
1483  *    commands are being sent to the host, so things are relatively quiet
1484  *    and we have freedom to fiddle with things as we wish.
1485  *
1486  *    This is only the *default* implementation.  it is possible for
1487  *    individual drivers to supply their own version of this function, and
1488  *    if the maintainer wishes to do this, it is strongly suggested that
1489  *    this function be taken as a template and modified.  this function
1490  *    was designed to correctly handle problems for about 95% of the
1491  *    different cases out there, and it should always provide at least a
1492  *    reasonable amount of error recovery.
1493  *
1494  *    Any command marked 'failed' or 'timeout' must eventually have
1495  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1496  *    here, so when we restart the host after we return it should have an
1497  *    empty queue.
1498  **/
1499 static void scsi_unjam_host(struct Scsi_Host *shost)
1500 {
1501         unsigned long flags;
1502         LIST_HEAD(eh_work_q);
1503         LIST_HEAD(eh_done_q);
1504
1505         spin_lock_irqsave(shost->host_lock, flags);
1506         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1507         spin_unlock_irqrestore(shost->host_lock, flags);
1508
1509         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1510
1511         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1512                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1513                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1514
1515         scsi_eh_flush_done_q(&eh_done_q);
1516 }
1517
1518 /**
1519  * scsi_error_handler - SCSI error handler thread
1520  * @data:       Host for which we are running.
1521  *
1522  * Notes:
1523  *    This is the main error handling loop.  This is run as a kernel thread
1524  *    for every SCSI host and handles all error handling activity.
1525  **/
1526 int scsi_error_handler(void *data)
1527 {
1528         struct Scsi_Host *shost = data;
1529
1530         current->flags |= PF_NOFREEZE;
1531
1532         /*
1533          * We use TASK_INTERRUPTIBLE so that the thread is not
1534          * counted against the load average as a running process.
1535          * We never actually get interrupted because kthread_run
1536          * disables singal delivery for the created thread.
1537          */
1538         set_current_state(TASK_INTERRUPTIBLE);
1539         while (!kthread_should_stop()) {
1540                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1541                     shost->host_failed != shost->host_busy) {
1542                         SCSI_LOG_ERROR_RECOVERY(1,
1543                                 printk("Error handler scsi_eh_%d sleeping\n",
1544                                         shost->host_no));
1545                         schedule();
1546                         set_current_state(TASK_INTERRUPTIBLE);
1547                         continue;
1548                 }
1549
1550                 __set_current_state(TASK_RUNNING);
1551                 SCSI_LOG_ERROR_RECOVERY(1,
1552                         printk("Error handler scsi_eh_%d waking up\n",
1553                                 shost->host_no));
1554
1555                 /*
1556                  * We have a host that is failing for some reason.  Figure out
1557                  * what we need to do to get it up and online again (if we can).
1558                  * If we fail, we end up taking the thing offline.
1559                  */
1560                 if (shost->transportt->eh_strategy_handler)
1561                         shost->transportt->eh_strategy_handler(shost);
1562                 else
1563                         scsi_unjam_host(shost);
1564
1565                 /*
1566                  * Note - if the above fails completely, the action is to take
1567                  * individual devices offline and flush the queue of any
1568                  * outstanding requests that may have been pending.  When we
1569                  * restart, we restart any I/O to any other devices on the bus
1570                  * which are still online.
1571                  */
1572                 scsi_restart_operations(shost);
1573                 set_current_state(TASK_INTERRUPTIBLE);
1574         }
1575         __set_current_state(TASK_RUNNING);
1576
1577         SCSI_LOG_ERROR_RECOVERY(1,
1578                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1579         shost->ehandler = NULL;
1580         return 0;
1581 }
1582
1583 /*
1584  * Function:    scsi_report_bus_reset()
1585  *
1586  * Purpose:     Utility function used by low-level drivers to report that
1587  *              they have observed a bus reset on the bus being handled.
1588  *
1589  * Arguments:   shost       - Host in question
1590  *              channel     - channel on which reset was observed.
1591  *
1592  * Returns:     Nothing
1593  *
1594  * Lock status: Host lock must be held.
1595  *
1596  * Notes:       This only needs to be called if the reset is one which
1597  *              originates from an unknown location.  Resets originated
1598  *              by the mid-level itself don't need to call this, but there
1599  *              should be no harm.
1600  *
1601  *              The main purpose of this is to make sure that a CHECK_CONDITION
1602  *              is properly treated.
1603  */
1604 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1605 {
1606         struct scsi_device *sdev;
1607
1608         __shost_for_each_device(sdev, shost) {
1609                 if (channel == sdev_channel(sdev)) {
1610                         sdev->was_reset = 1;
1611                         sdev->expecting_cc_ua = 1;
1612                 }
1613         }
1614 }
1615 EXPORT_SYMBOL(scsi_report_bus_reset);
1616
1617 /*
1618  * Function:    scsi_report_device_reset()
1619  *
1620  * Purpose:     Utility function used by low-level drivers to report that
1621  *              they have observed a device reset on the device being handled.
1622  *
1623  * Arguments:   shost       - Host in question
1624  *              channel     - channel on which reset was observed
1625  *              target      - target on which reset was observed
1626  *
1627  * Returns:     Nothing
1628  *
1629  * Lock status: Host lock must be held
1630  *
1631  * Notes:       This only needs to be called if the reset is one which
1632  *              originates from an unknown location.  Resets originated
1633  *              by the mid-level itself don't need to call this, but there
1634  *              should be no harm.
1635  *
1636  *              The main purpose of this is to make sure that a CHECK_CONDITION
1637  *              is properly treated.
1638  */
1639 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1640 {
1641         struct scsi_device *sdev;
1642
1643         __shost_for_each_device(sdev, shost) {
1644                 if (channel == sdev_channel(sdev) &&
1645                     target == sdev_id(sdev)) {
1646                         sdev->was_reset = 1;
1647                         sdev->expecting_cc_ua = 1;
1648                 }
1649         }
1650 }
1651 EXPORT_SYMBOL(scsi_report_device_reset);
1652
1653 static void
1654 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1655 {
1656 }
1657
1658 /*
1659  * Function:    scsi_reset_provider
1660  *
1661  * Purpose:     Send requested reset to a bus or device at any phase.
1662  *
1663  * Arguments:   device  - device to send reset to
1664  *              flag - reset type (see scsi.h)
1665  *
1666  * Returns:     SUCCESS/FAILURE.
1667  *
1668  * Notes:       This is used by the SCSI Generic driver to provide
1669  *              Bus/Device reset capability.
1670  */
1671 int
1672 scsi_reset_provider(struct scsi_device *dev, int flag)
1673 {
1674         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1675         struct request req;
1676         int rtn;
1677
1678         scmd->request = &req;
1679         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1680
1681         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1682     
1683         scmd->scsi_done         = scsi_reset_provider_done_command;
1684         scmd->done                      = NULL;
1685         scmd->buffer                    = NULL;
1686         scmd->bufflen                   = 0;
1687         scmd->request_buffer            = NULL;
1688         scmd->request_bufflen           = 0;
1689
1690         scmd->cmd_len                   = 0;
1691
1692         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1693
1694         init_timer(&scmd->eh_timeout);
1695
1696         /*
1697          * Sometimes the command can get back into the timer chain,
1698          * so use the pid as an identifier.
1699          */
1700         scmd->pid                       = 0;
1701
1702         switch (flag) {
1703         case SCSI_TRY_RESET_DEVICE:
1704                 rtn = scsi_try_bus_device_reset(scmd);
1705                 if (rtn == SUCCESS)
1706                         break;
1707                 /* FALLTHROUGH */
1708         case SCSI_TRY_RESET_BUS:
1709                 rtn = scsi_try_bus_reset(scmd);
1710                 if (rtn == SUCCESS)
1711                         break;
1712                 /* FALLTHROUGH */
1713         case SCSI_TRY_RESET_HOST:
1714                 rtn = scsi_try_host_reset(scmd);
1715                 break;
1716         default:
1717                 rtn = FAILED;
1718         }
1719
1720         scsi_next_command(scmd);
1721         return rtn;
1722 }
1723 EXPORT_SYMBOL(scsi_reset_provider);
1724
1725 /**
1726  * scsi_normalize_sense - normalize main elements from either fixed or
1727  *                      descriptor sense data format into a common format.
1728  *
1729  * @sense_buffer:       byte array containing sense data returned by device
1730  * @sb_len:             number of valid bytes in sense_buffer
1731  * @sshdr:              pointer to instance of structure that common
1732  *                      elements are written to.
1733  *
1734  * Notes:
1735  *      The "main elements" from sense data are: response_code, sense_key,
1736  *      asc, ascq and additional_length (only for descriptor format).
1737  *
1738  *      Typically this function can be called after a device has
1739  *      responded to a SCSI command with the CHECK_CONDITION status.
1740  *
1741  * Return value:
1742  *      1 if valid sense data information found, else 0;
1743  **/
1744 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1745                          struct scsi_sense_hdr *sshdr)
1746 {
1747         if (!sense_buffer || !sb_len)
1748                 return 0;
1749
1750         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1751
1752         sshdr->response_code = (sense_buffer[0] & 0x7f);
1753
1754         if (!scsi_sense_valid(sshdr))
1755                 return 0;
1756
1757         if (sshdr->response_code >= 0x72) {
1758                 /*
1759                  * descriptor format
1760                  */
1761                 if (sb_len > 1)
1762                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1763                 if (sb_len > 2)
1764                         sshdr->asc = sense_buffer[2];
1765                 if (sb_len > 3)
1766                         sshdr->ascq = sense_buffer[3];
1767                 if (sb_len > 7)
1768                         sshdr->additional_length = sense_buffer[7];
1769         } else {
1770                 /* 
1771                  * fixed format
1772                  */
1773                 if (sb_len > 2)
1774                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1775                 if (sb_len > 7) {
1776                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1777                                          sb_len : (sense_buffer[7] + 8);
1778                         if (sb_len > 12)
1779                                 sshdr->asc = sense_buffer[12];
1780                         if (sb_len > 13)
1781                                 sshdr->ascq = sense_buffer[13];
1782                 }
1783         }
1784
1785         return 1;
1786 }
1787 EXPORT_SYMBOL(scsi_normalize_sense);
1788
1789 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1790                                  struct scsi_sense_hdr *sshdr)
1791 {
1792         return scsi_normalize_sense(cmd->sense_buffer,
1793                         sizeof(cmd->sense_buffer), sshdr);
1794 }
1795 EXPORT_SYMBOL(scsi_command_normalize_sense);
1796
1797 /**
1798  * scsi_sense_desc_find - search for a given descriptor type in
1799  *                      descriptor sense data format.
1800  *
1801  * @sense_buffer:       byte array of descriptor format sense data
1802  * @sb_len:             number of valid bytes in sense_buffer
1803  * @desc_type:          value of descriptor type to find
1804  *                      (e.g. 0 -> information)
1805  *
1806  * Notes:
1807  *      only valid when sense data is in descriptor format
1808  *
1809  * Return value:
1810  *      pointer to start of (first) descriptor if found else NULL
1811  **/
1812 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1813                                 int desc_type)
1814 {
1815         int add_sen_len, add_len, desc_len, k;
1816         const u8 * descp;
1817
1818         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1819                 return NULL;
1820         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1821                 return NULL;
1822         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1823                         add_sen_len : (sb_len - 8);
1824         descp = &sense_buffer[8];
1825         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1826                 descp += desc_len;
1827                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1828                 desc_len = add_len + 2;
1829                 if (descp[0] == desc_type)
1830                         return descp;
1831                 if (add_len < 0) // short descriptor ??
1832                         break;
1833         }
1834         return NULL;
1835 }
1836 EXPORT_SYMBOL(scsi_sense_desc_find);
1837
1838 /**
1839  * scsi_get_sense_info_fld - attempts to get information field from
1840  *                      sense data (either fixed or descriptor format)
1841  *
1842  * @sense_buffer:       byte array of sense data
1843  * @sb_len:             number of valid bytes in sense_buffer
1844  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1845  *                      field will be placed if found.
1846  *
1847  * Return value:
1848  *      1 if information field found, 0 if not found.
1849  **/
1850 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1851                             u64 * info_out)
1852 {
1853         int j;
1854         const u8 * ucp;
1855         u64 ull;
1856
1857         if (sb_len < 7)
1858                 return 0;
1859         switch (sense_buffer[0] & 0x7f) {
1860         case 0x70:
1861         case 0x71:
1862                 if (sense_buffer[0] & 0x80) {
1863                         *info_out = (sense_buffer[3] << 24) +
1864                                     (sense_buffer[4] << 16) +
1865                                     (sense_buffer[5] << 8) + sense_buffer[6];
1866                         return 1;
1867                 } else
1868                         return 0;
1869         case 0x72:
1870         case 0x73:
1871                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1872                                            0 /* info desc */);
1873                 if (ucp && (0xa == ucp[1])) {
1874                         ull = 0;
1875                         for (j = 0; j < 8; ++j) {
1876                                 if (j > 0)
1877                                         ull <<= 8;
1878                                 ull |= ucp[4 + j];
1879                         }
1880                         *info_out = ull;
1881                         return 1;
1882                 } else
1883                         return 0;
1884         default:
1885                 return 0;
1886         }
1887 }
1888 EXPORT_SYMBOL(scsi_get_sense_info_fld);