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