Automatic merge with /usr/src/ntfs-2.6.git.
[linux-2.6] / 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/interrupt.h>
24 #include <linux/blkdev.h>
25 #include <linux/delay.h>
26
27 #include <scsi/scsi.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_eh.h>
31 #include <scsi/scsi_host.h>
32 #include <scsi/scsi_ioctl.h>
33 #include <scsi/scsi_request.h>
34
35 #include "scsi_priv.h"
36 #include "scsi_logging.h"
37
38 #define SENSE_TIMEOUT           (10*HZ)
39 #define START_UNIT_TIMEOUT      (30*HZ)
40
41 /*
42  * These should *probably* be handled by the host itself.
43  * Since it is allowed to sleep, it probably should.
44  */
45 #define BUS_RESET_SETTLE_TIME   (10)
46 #define HOST_RESET_SETTLE_TIME  (10)
47
48 /* called with shost->host_lock held */
49 void scsi_eh_wakeup(struct Scsi_Host *shost)
50 {
51         if (shost->host_busy == shost->host_failed) {
52                 up(shost->eh_wait);
53                 SCSI_LOG_ERROR_RECOVERY(5,
54                                 printk("Waking error handler thread\n"));
55         }
56 }
57
58 /**
59  * scsi_eh_scmd_add - add scsi cmd to error handling.
60  * @scmd:       scmd to run eh on.
61  * @eh_flag:    optional SCSI_EH flag.
62  *
63  * Return value:
64  *      0 on failure.
65  **/
66 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
67 {
68         struct Scsi_Host *shost = scmd->device->host;
69         unsigned long flags;
70
71         if (shost->eh_wait == NULL)
72                 return 0;
73
74         spin_lock_irqsave(shost->host_lock, flags);
75
76         scsi_eh_eflags_set(scmd, eh_flag);
77         /*
78          * FIXME: Can we stop setting owner and state.
79          */
80         scmd->owner = SCSI_OWNER_ERROR_HANDLER;
81         scmd->state = SCSI_STATE_FAILED;
82         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
83         set_bit(SHOST_RECOVERY, &shost->shost_state);
84         shost->host_failed++;
85         scsi_eh_wakeup(shost);
86         spin_unlock_irqrestore(shost->host_lock, flags);
87         return 1;
88 }
89
90 /**
91  * scsi_add_timer - Start timeout timer for a single scsi command.
92  * @scmd:       scsi command that is about to start running.
93  * @timeout:    amount of time to allow this command to run.
94  * @complete:   timeout function to call if timer isn't canceled.
95  *
96  * Notes:
97  *    This should be turned into an inline function.  Each scsi command
98  *    has its own timer, and as it is added to the queue, we set up the
99  *    timer.  When the command completes, we cancel the timer.
100  **/
101 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
102                     void (*complete)(struct scsi_cmnd *))
103 {
104
105         /*
106          * If the clock was already running for this command, then
107          * first delete the timer.  The timer handling code gets rather
108          * confused if we don't do this.
109          */
110         if (scmd->eh_timeout.function)
111                 del_timer(&scmd->eh_timeout);
112
113         scmd->eh_timeout.data = (unsigned long)scmd;
114         scmd->eh_timeout.expires = jiffies + timeout;
115         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
116
117         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
118                                           " %d, (%p)\n", __FUNCTION__,
119                                           scmd, timeout, complete));
120
121         add_timer(&scmd->eh_timeout);
122 }
123 EXPORT_SYMBOL(scsi_add_timer);
124
125 /**
126  * scsi_delete_timer - Delete/cancel timer for a given function.
127  * @scmd:       Cmd that we are canceling timer for
128  *
129  * Notes:
130  *     This should be turned into an inline function.
131  *
132  * Return value:
133  *     1 if we were able to detach the timer.  0 if we blew it, and the
134  *     timer function has already started to run.
135  **/
136 int scsi_delete_timer(struct scsi_cmnd *scmd)
137 {
138         int rtn;
139
140         rtn = del_timer(&scmd->eh_timeout);
141
142         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
143                                          " rtn: %d\n", __FUNCTION__,
144                                          scmd, rtn));
145
146         scmd->eh_timeout.data = (unsigned long)NULL;
147         scmd->eh_timeout.function = NULL;
148
149         return rtn;
150 }
151 EXPORT_SYMBOL(scsi_delete_timer);
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->hostt->eh_timed_out)
168                 switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
169                 case EH_HANDLED:
170                         __scsi_done(scmd);
171                         return;
172                 case EH_RESET_TIMER:
173                         /* This allows a single retry even of a command
174                          * with allowed == 0 */
175                         if (scmd->retries++ > scmd->allowed)
176                                 break;
177                         scsi_add_timer(scmd, scmd->timeout_per_command,
178                                        scsi_times_out);
179                         return;
180                 case EH_NOT_HANDLED:
181                         break;
182                 }
183
184         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
185                 panic("Error handler thread not present at %p %p %s %d",
186                       scmd, scmd->device->host, __FILE__, __LINE__);
187         }
188 }
189
190 /**
191  * scsi_block_when_processing_errors - Prevent cmds from being queued.
192  * @sdev:       Device on which we are performing recovery.
193  *
194  * Description:
195  *     We block until the host is out of error recovery, and then check to
196  *     see whether the host or the device is offline.
197  *
198  * Return value:
199  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
200  **/
201 int scsi_block_when_processing_errors(struct scsi_device *sdev)
202 {
203         int online;
204
205         wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state)));
206
207         online = scsi_device_online(sdev);
208
209         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
210                                           online));
211
212         return online;
213 }
214 EXPORT_SYMBOL(scsi_block_when_processing_errors);
215
216 #ifdef CONFIG_SCSI_LOGGING
217 /**
218  * scsi_eh_prt_fail_stats - Log info on failures.
219  * @shost:      scsi host being recovered.
220  * @work_q:     Queue of scsi cmds to process.
221  **/
222 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
223                                           struct list_head *work_q)
224 {
225         struct scsi_cmnd *scmd;
226         struct scsi_device *sdev;
227         int total_failures = 0;
228         int cmd_failed = 0;
229         int cmd_cancel = 0;
230         int devices_failed = 0;
231
232         shost_for_each_device(sdev, shost) {
233                 list_for_each_entry(scmd, work_q, eh_entry) {
234                         if (scmd->device == sdev) {
235                                 ++total_failures;
236                                 if (scsi_eh_eflags_chk(scmd,
237                                                        SCSI_EH_CANCEL_CMD))
238                                         ++cmd_cancel;
239                                 else 
240                                         ++cmd_failed;
241                         }
242                 }
243
244                 if (cmd_cancel || cmd_failed) {
245                         SCSI_LOG_ERROR_RECOVERY(3,
246                                 printk("%s: %d:%d:%d:%d cmds failed: %d,"
247                                        " cancel: %d\n",
248                                        __FUNCTION__, shost->host_no,
249                                        sdev->channel, sdev->id, sdev->lun,
250                                        cmd_failed, cmd_cancel));
251                         cmd_cancel = 0;
252                         cmd_failed = 0;
253                         ++devices_failed;
254                 }
255         }
256
257         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
258                                           " devices require eh work\n",
259                                   total_failures, devices_failed));
260 }
261 #endif
262
263 /**
264  * scsi_check_sense - Examine scsi cmd sense
265  * @scmd:       Cmd to have sense checked.
266  *
267  * Return value:
268  *      SUCCESS or FAILED or NEEDS_RETRY
269  *
270  * Notes:
271  *      When a deferred error is detected the current command has
272  *      not been executed and needs retrying.
273  **/
274 static int scsi_check_sense(struct scsi_cmnd *scmd)
275 {
276         struct scsi_sense_hdr sshdr;
277
278         if (! scsi_command_normalize_sense(scmd, &sshdr))
279                 return FAILED;  /* no valid sense data */
280
281         if (scsi_sense_is_deferred(&sshdr))
282                 return NEEDS_RETRY;
283
284         /*
285          * Previous logic looked for FILEMARK, EOM or ILI which are
286          * mainly associated with tapes and returned SUCCESS.
287          */
288         if (sshdr.response_code == 0x70) {
289                 /* fixed format */
290                 if (scmd->sense_buffer[2] & 0xe0)
291                         return SUCCESS;
292         } else {
293                 /*
294                  * descriptor format: look for "stream commands sense data
295                  * descriptor" (see SSC-3). Assume single sense data
296                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
297                  */
298                 if ((sshdr.additional_length > 3) &&
299                     (scmd->sense_buffer[8] == 0x4) &&
300                     (scmd->sense_buffer[11] & 0xe0))
301                         return SUCCESS;
302         }
303
304         switch (sshdr.sense_key) {
305         case NO_SENSE:
306                 return SUCCESS;
307         case RECOVERED_ERROR:
308                 return /* soft_error */ SUCCESS;
309
310         case ABORTED_COMMAND:
311                 return NEEDS_RETRY;
312         case NOT_READY:
313         case UNIT_ATTENTION:
314                 /*
315                  * if we are expecting a cc/ua because of a bus reset that we
316                  * performed, treat this just as a retry.  otherwise this is
317                  * information that we should pass up to the upper-level driver
318                  * so that we can deal with it there.
319                  */
320                 if (scmd->device->expecting_cc_ua) {
321                         scmd->device->expecting_cc_ua = 0;
322                         return NEEDS_RETRY;
323                 }
324                 /*
325                  * if the device is in the process of becoming ready, we 
326                  * should retry.
327                  */
328                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
329                         return NEEDS_RETRY;
330                 /*
331                  * if the device is not started, we need to wake
332                  * the error handler to start the motor
333                  */
334                 if (scmd->device->allow_restart &&
335                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
336                         return FAILED;
337                 return SUCCESS;
338
339                 /* these three are not supported */
340         case COPY_ABORTED:
341         case VOLUME_OVERFLOW:
342         case MISCOMPARE:
343                 return SUCCESS;
344
345         case MEDIUM_ERROR:
346                 return NEEDS_RETRY;
347
348         case HARDWARE_ERROR:
349                 if (scmd->device->retry_hwerror)
350                         return NEEDS_RETRY;
351                 else
352                         return SUCCESS;
353
354         case ILLEGAL_REQUEST:
355         case BLANK_CHECK:
356         case DATA_PROTECT:
357         default:
358                 return SUCCESS;
359         }
360 }
361
362 /**
363  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
364  * @scmd:       SCSI cmd to examine.
365  *
366  * Notes:
367  *    This is *only* called when we are examining the status of commands
368  *    queued during error recovery.  the main difference here is that we
369  *    don't allow for the possibility of retries here, and we are a lot
370  *    more restrictive about what we consider acceptable.
371  **/
372 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
373 {
374         /*
375          * first check the host byte, to see if there is anything in there
376          * that would indicate what we need to do.
377          */
378         if (host_byte(scmd->result) == DID_RESET) {
379                 /*
380                  * rats.  we are already in the error handler, so we now
381                  * get to try and figure out what to do next.  if the sense
382                  * is valid, we have a pretty good idea of what to do.
383                  * if not, we mark it as FAILED.
384                  */
385                 return scsi_check_sense(scmd);
386         }
387         if (host_byte(scmd->result) != DID_OK)
388                 return FAILED;
389
390         /*
391          * next, check the message byte.
392          */
393         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
394                 return FAILED;
395
396         /*
397          * now, check the status byte to see if this indicates
398          * anything special.
399          */
400         switch (status_byte(scmd->result)) {
401         case GOOD:
402         case COMMAND_TERMINATED:
403                 return SUCCESS;
404         case CHECK_CONDITION:
405                 return scsi_check_sense(scmd);
406         case CONDITION_GOOD:
407         case INTERMEDIATE_GOOD:
408         case INTERMEDIATE_C_GOOD:
409                 /*
410                  * who knows?  FIXME(eric)
411                  */
412                 return SUCCESS;
413         case BUSY:
414         case QUEUE_FULL:
415         case RESERVATION_CONFLICT:
416         default:
417                 return FAILED;
418         }
419         return FAILED;
420 }
421
422 /**
423  * scsi_eh_times_out - timeout function for error handling.
424  * @scmd:       Cmd that is timing out.
425  *
426  * Notes:
427  *    During error handling, the kernel thread will be sleeping waiting
428  *    for some action to complete on the device.  our only job is to
429  *    record that it timed out, and to wake up the thread.
430  **/
431 static void scsi_eh_times_out(struct scsi_cmnd *scmd)
432 {
433         scsi_eh_eflags_set(scmd, SCSI_EH_REC_TIMEOUT);
434         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
435                                           scmd));
436
437         up(scmd->device->host->eh_action);
438 }
439
440 /**
441  * scsi_eh_done - Completion function for error handling.
442  * @scmd:       Cmd that is done.
443  **/
444 static void scsi_eh_done(struct scsi_cmnd *scmd)
445 {
446         /*
447          * if the timeout handler is already running, then just set the
448          * flag which says we finished late, and return.  we have no
449          * way of stopping the timeout handler from running, so we must
450          * always defer to it.
451          */
452         if (del_timer(&scmd->eh_timeout)) {
453                 scmd->request->rq_status = RQ_SCSI_DONE;
454                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
455
456                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
457                                            __FUNCTION__, scmd, scmd->result));
458
459                 up(scmd->device->host->eh_action);
460         }
461 }
462
463 /**
464  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
465  * @scmd:       SCSI Cmd to send.
466  * @timeout:    Timeout for cmd.
467  *
468  * Notes:
469  *    The initialization of the structures is quite a bit different in
470  *    this case, and furthermore, there is a different completion handler
471  *    vs scsi_dispatch_cmd.
472  * Return value:
473  *    SUCCESS or FAILED or NEEDS_RETRY
474  **/
475 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
476 {
477         struct scsi_device *sdev = scmd->device;
478         struct Scsi_Host *shost = sdev->host;
479         DECLARE_MUTEX_LOCKED(sem);
480         unsigned long flags;
481         int rtn = SUCCESS;
482
483         /*
484          * we will use a queued command if possible, otherwise we will
485          * emulate the queuing and calling of completion function ourselves.
486          */
487         scmd->owner = SCSI_OWNER_LOWLEVEL;
488
489         if (sdev->scsi_level <= SCSI_2)
490                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
491                         (sdev->lun << 5 & 0xe0);
492
493         scsi_add_timer(scmd, timeout, scsi_eh_times_out);
494
495         /*
496          * set up the semaphore so we wait for the command to complete.
497          */
498         shost->eh_action = &sem;
499         scmd->request->rq_status = RQ_SCSI_BUSY;
500
501         spin_lock_irqsave(shost->host_lock, flags);
502         scsi_log_send(scmd);
503         shost->hostt->queuecommand(scmd, scsi_eh_done);
504         spin_unlock_irqrestore(shost->host_lock, flags);
505
506         down(&sem);
507         scsi_log_completion(scmd, SUCCESS);
508
509         shost->eh_action = NULL;
510
511         /*
512          * see if timeout.  if so, tell the host to forget about it.
513          * in other words, we don't want a callback any more.
514          */
515         if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
516                 scsi_eh_eflags_clr(scmd,  SCSI_EH_REC_TIMEOUT);
517                 scmd->owner = SCSI_OWNER_LOWLEVEL;
518
519                 /*
520                  * as far as the low level driver is
521                  * concerned, this command is still active, so
522                  * we must give the low level driver a chance
523                  * to abort it. (db) 
524                  *
525                  * FIXME(eric) - we are not tracking whether we could
526                  * abort a timed out command or not.  not sure how
527                  * we should treat them differently anyways.
528                  */
529                 if (shost->hostt->eh_abort_handler)
530                         shost->hostt->eh_abort_handler(scmd);
531                         
532                 scmd->request->rq_status = RQ_SCSI_DONE;
533                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
534                         
535                 rtn = FAILED;
536         }
537
538         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
539                                           __FUNCTION__, scmd, rtn));
540
541         /*
542          * now examine the actual status codes to see whether the command
543          * actually did complete normally.
544          */
545         if (rtn == SUCCESS) {
546                 rtn = scsi_eh_completed_normally(scmd);
547                 SCSI_LOG_ERROR_RECOVERY(3,
548                         printk("%s: scsi_eh_completed_normally %x\n",
549                                __FUNCTION__, rtn));
550                 switch (rtn) {
551                 case SUCCESS:
552                 case NEEDS_RETRY:
553                 case FAILED:
554                         break;
555                 default:
556                         rtn = FAILED;
557                         break;
558                 }
559         }
560
561         return rtn;
562 }
563
564 /**
565  * scsi_request_sense - Request sense data from a particular target.
566  * @scmd:       SCSI cmd for request sense.
567  *
568  * Notes:
569  *    Some hosts automatically obtain this information, others require
570  *    that we obtain it on our own. This function will *not* return until
571  *    the command either times out, or it completes.
572  **/
573 static int scsi_request_sense(struct scsi_cmnd *scmd)
574 {
575         static unsigned char generic_sense[6] =
576         {REQUEST_SENSE, 0, 0, 0, 252, 0};
577         unsigned char *scsi_result;
578         int saved_result;
579         int rtn;
580
581         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
582
583         scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
584
585
586         if (unlikely(!scsi_result)) {
587                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
588                        __FUNCTION__);
589                 return FAILED;
590         }
591
592         /*
593          * zero the sense buffer.  some host adapters automatically always
594          * request sense, so it is not a good idea that
595          * scmd->request_buffer and scmd->sense_buffer point to the same
596          * address (db).  0 is not a valid sense code. 
597          */
598         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
599         memset(scsi_result, 0, 252);
600
601         saved_result = scmd->result;
602         scmd->request_buffer = scsi_result;
603         scmd->request_bufflen = 252;
604         scmd->use_sg = 0;
605         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
606         scmd->sc_data_direction = DMA_FROM_DEVICE;
607         scmd->underflow = 0;
608
609         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
610
611         /* last chance to have valid sense data */
612         if(!SCSI_SENSE_VALID(scmd)) {
613                 memcpy(scmd->sense_buffer, scmd->request_buffer,
614                        sizeof(scmd->sense_buffer));
615         }
616
617         kfree(scsi_result);
618
619         /*
620          * when we eventually call scsi_finish, we really wish to complete
621          * the original request, so let's restore the original data. (db)
622          */
623         scsi_setup_cmd_retry(scmd);
624         scmd->result = saved_result;
625         return rtn;
626 }
627
628 /**
629  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
630  * @scmd:       Original SCSI cmd that eh has finished.
631  * @done_q:     Queue for processed commands.
632  *
633  * Notes:
634  *    We don't want to use the normal command completion while we are are
635  *    still handling errors - it may cause other commands to be queued,
636  *    and that would disturb what we are doing.  thus we really want to
637  *    keep a list of pending commands for final completion, and once we
638  *    are ready to leave error handling we handle completion for real.
639  **/
640 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
641                                struct list_head *done_q)
642 {
643         scmd->device->host->host_failed--;
644         scmd->state = SCSI_STATE_BHQUEUE;
645
646         scsi_eh_eflags_clr_all(scmd);
647
648         /*
649          * set this back so that the upper level can correctly free up
650          * things.
651          */
652         scsi_setup_cmd_retry(scmd);
653         list_move_tail(&scmd->eh_entry, done_q);
654 }
655
656 /**
657  * scsi_eh_get_sense - Get device sense data.
658  * @work_q:     Queue of commands to process.
659  * @done_q:     Queue of proccessed commands..
660  *
661  * Description:
662  *    See if we need to request sense information.  if so, then get it
663  *    now, so we have a better idea of what to do.  
664  *
665  * Notes:
666  *    This has the unfortunate side effect that if a shost adapter does
667  *    not automatically request sense information, that we end up shutting
668  *    it down before we request it.
669  *
670  *    All drivers should request sense information internally these days,
671  *    so for now all I have to say is tough noogies if you end up in here.
672  *
673  *    XXX: Long term this code should go away, but that needs an audit of
674  *         all LLDDs first.
675  **/
676 static int scsi_eh_get_sense(struct list_head *work_q,
677                              struct list_head *done_q)
678 {
679         struct list_head *lh, *lh_sf;
680         struct scsi_cmnd *scmd;
681         int rtn;
682
683         list_for_each_safe(lh, lh_sf, work_q) {
684                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
685                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
686                     SCSI_SENSE_VALID(scmd))
687                         continue;
688
689                 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
690                                                   " for id: %d\n",
691                                                   current->comm,
692                                                   scmd->device->id));
693                 rtn = scsi_request_sense(scmd);
694                 if (rtn != SUCCESS)
695                         continue;
696
697                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
698                                                   " result %x\n", scmd,
699                                                   scmd->result));
700                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
701
702                 rtn = scsi_decide_disposition(scmd);
703
704                 /*
705                  * if the result was normal, then just pass it along to the
706                  * upper level.
707                  */
708                 if (rtn == SUCCESS)
709                         /* we don't want this command reissued, just
710                          * finished with the sense data, so set
711                          * retries to the max allowed to ensure it
712                          * won't get reissued */
713                         scmd->retries = scmd->allowed;
714                 else if (rtn != NEEDS_RETRY)
715                         continue;
716
717                 scsi_eh_finish_cmd(scmd, done_q);
718         }
719
720         return list_empty(work_q);
721 }
722
723 /**
724  * scsi_try_to_abort_cmd - Ask host to abort a running command.
725  * @scmd:       SCSI cmd to abort from Lower Level.
726  *
727  * Notes:
728  *    This function will not return until the user's completion function
729  *    has been called.  there is no timeout on this operation.  if the
730  *    author of the low-level driver wishes this operation to be timed,
731  *    they can provide this facility themselves.  helper functions in
732  *    scsi_error.c can be supplied to make this easier to do.
733  **/
734 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
735 {
736         if (!scmd->device->host->hostt->eh_abort_handler)
737                 return FAILED;
738
739         /*
740          * scsi_done was called just after the command timed out and before
741          * we had a chance to process it. (db)
742          */
743         if (scmd->serial_number == 0)
744                 return SUCCESS;
745
746         scmd->owner = SCSI_OWNER_LOWLEVEL;
747
748         return scmd->device->host->hostt->eh_abort_handler(scmd);
749 }
750
751 /**
752  * scsi_eh_tur - Send TUR to device.
753  * @scmd:       Scsi cmd to send TUR
754  *
755  * Return value:
756  *    0 - Device is ready. 1 - Device NOT ready.
757  **/
758 static int scsi_eh_tur(struct scsi_cmnd *scmd)
759 {
760         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
761         int retry_cnt = 1, rtn;
762         int saved_result;
763
764 retry_tur:
765         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
766
767         /*
768          * zero the sense buffer.  the scsi spec mandates that any
769          * untransferred sense data should be interpreted as being zero.
770          */
771         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
772
773         saved_result = scmd->result;
774         scmd->request_buffer = NULL;
775         scmd->request_bufflen = 0;
776         scmd->use_sg = 0;
777         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
778         scmd->underflow = 0;
779         scmd->sc_data_direction = DMA_NONE;
780
781         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
782
783         /*
784          * when we eventually call scsi_finish, we really wish to complete
785          * the original request, so let's restore the original data. (db)
786          */
787         scsi_setup_cmd_retry(scmd);
788         scmd->result = saved_result;
789
790         /*
791          * hey, we are done.  let's look to see what happened.
792          */
793         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
794                 __FUNCTION__, scmd, rtn));
795         if (rtn == SUCCESS)
796                 return 0;
797         else if (rtn == NEEDS_RETRY)
798                 if (retry_cnt--)
799                         goto retry_tur;
800         return 1;
801 }
802
803 /**
804  * scsi_eh_abort_cmds - abort canceled commands.
805  * @shost:      scsi host being recovered.
806  * @eh_done_q:  list_head for processed commands.
807  *
808  * Decription:
809  *    Try and see whether or not it makes sense to try and abort the
810  *    running command.  this only works out to be the case if we have one
811  *    command that has timed out.  if the command simply failed, it makes
812  *    no sense to try and abort the command, since as far as the shost
813  *    adapter is concerned, it isn't running.
814  **/
815 static int scsi_eh_abort_cmds(struct list_head *work_q,
816                               struct list_head *done_q)
817 {
818         struct list_head *lh, *lh_sf;
819         struct scsi_cmnd *scmd;
820         int rtn;
821
822         list_for_each_safe(lh, lh_sf, work_q) {
823                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
824                 if (!scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD))
825                         continue;
826                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
827                                                   "0x%p\n", current->comm,
828                                                   scmd));
829                 rtn = scsi_try_to_abort_cmd(scmd);
830                 if (rtn == SUCCESS) {
831                         scsi_eh_eflags_clr(scmd,  SCSI_EH_CANCEL_CMD);
832                         if (!scsi_device_online(scmd->device) ||
833                             !scsi_eh_tur(scmd)) {
834                                 scsi_eh_finish_cmd(scmd, done_q);
835                         }
836                                 
837                 } else
838                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
839                                                           " cmd failed:"
840                                                           "0x%p\n",
841                                                           current->comm,
842                                                           scmd));
843         }
844
845         return list_empty(work_q);
846 }
847
848 /**
849  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
850  * @scmd:       SCSI cmd used to send BDR       
851  *
852  * Notes:
853  *    There is no timeout for this operation.  if this operation is
854  *    unreliable for a given host, then the host itself needs to put a
855  *    timer on it, and set the host back to a consistent state prior to
856  *    returning.
857  **/
858 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
859 {
860         int rtn;
861
862         if (!scmd->device->host->hostt->eh_device_reset_handler)
863                 return FAILED;
864
865         scmd->owner = SCSI_OWNER_LOWLEVEL;
866
867         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
868
869         if (rtn == SUCCESS) {
870                 scmd->device->was_reset = 1;
871                 scmd->device->expecting_cc_ua = 1;
872         }
873
874         return rtn;
875 }
876
877 /**
878  * scsi_eh_try_stu - Send START_UNIT to device.
879  * @scmd:       Scsi cmd to send START_UNIT
880  *
881  * Return value:
882  *    0 - Device is ready. 1 - Device NOT ready.
883  **/
884 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
885 {
886         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
887         int rtn;
888         int saved_result;
889
890         if (!scmd->device->allow_restart)
891                 return 1;
892
893         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
894
895         /*
896          * zero the sense buffer.  the scsi spec mandates that any
897          * untransferred sense data should be interpreted as being zero.
898          */
899         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
900
901         saved_result = scmd->result;
902         scmd->request_buffer = NULL;
903         scmd->request_bufflen = 0;
904         scmd->use_sg = 0;
905         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
906         scmd->underflow = 0;
907         scmd->sc_data_direction = DMA_NONE;
908
909         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
910
911         /*
912          * when we eventually call scsi_finish, we really wish to complete
913          * the original request, so let's restore the original data. (db)
914          */
915         scsi_setup_cmd_retry(scmd);
916         scmd->result = saved_result;
917
918         /*
919          * hey, we are done.  let's look to see what happened.
920          */
921         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
922                 __FUNCTION__, scmd, rtn));
923         if (rtn == SUCCESS)
924                 return 0;
925         return 1;
926 }
927
928  /**
929  * scsi_eh_stu - send START_UNIT if needed
930  * @shost:      scsi host being recovered.
931  * @eh_done_q:  list_head for processed commands.
932  *
933  * Notes:
934  *    If commands are failing due to not ready, initializing command required,
935  *      try revalidating the device, which will end up sending a start unit. 
936  **/
937 static int scsi_eh_stu(struct Scsi_Host *shost,
938                               struct list_head *work_q,
939                               struct list_head *done_q)
940 {
941         struct list_head *lh, *lh_sf;
942         struct scsi_cmnd *scmd, *stu_scmd;
943         struct scsi_device *sdev;
944
945         shost_for_each_device(sdev, shost) {
946                 stu_scmd = NULL;
947                 list_for_each_entry(scmd, work_q, eh_entry)
948                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
949                             scsi_check_sense(scmd) == FAILED ) {
950                                 stu_scmd = scmd;
951                                 break;
952                         }
953
954                 if (!stu_scmd)
955                         continue;
956
957                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
958                                                   " 0x%p\n", current->comm, sdev));
959
960                 if (!scsi_eh_try_stu(stu_scmd)) {
961                         if (!scsi_device_online(sdev) ||
962                             !scsi_eh_tur(stu_scmd)) {
963                                 list_for_each_safe(lh, lh_sf, work_q) {
964                                         scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
965                                         if (scmd->device == sdev)
966                                                 scsi_eh_finish_cmd(scmd, done_q);
967                                 }
968                         }
969                 } else {
970                         SCSI_LOG_ERROR_RECOVERY(3,
971                                                 printk("%s: START_UNIT failed to sdev:"
972                                                        " 0x%p\n", current->comm, sdev));
973                 }
974         }
975
976         return list_empty(work_q);
977 }
978
979
980 /**
981  * scsi_eh_bus_device_reset - send bdr if needed
982  * @shost:      scsi host being recovered.
983  * @eh_done_q:  list_head for processed commands.
984  *
985  * Notes:
986  *    Try a bus device reset.  still, look to see whether we have multiple
987  *    devices that are jammed or not - if we have multiple devices, it
988  *    makes no sense to try bus_device_reset - we really would need to try
989  *    a bus_reset instead. 
990  **/
991 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
992                                     struct list_head *work_q,
993                                     struct list_head *done_q)
994 {
995         struct list_head *lh, *lh_sf;
996         struct scsi_cmnd *scmd, *bdr_scmd;
997         struct scsi_device *sdev;
998         int rtn;
999
1000         shost_for_each_device(sdev, shost) {
1001                 bdr_scmd = NULL;
1002                 list_for_each_entry(scmd, work_q, eh_entry)
1003                         if (scmd->device == sdev) {
1004                                 bdr_scmd = scmd;
1005                                 break;
1006                         }
1007
1008                 if (!bdr_scmd)
1009                         continue;
1010
1011                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1012                                                   " 0x%p\n", current->comm,
1013                                                   sdev));
1014                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1015                 if (rtn == SUCCESS) {
1016                         if (!scsi_device_online(sdev) ||
1017                             !scsi_eh_tur(bdr_scmd)) {
1018                                 list_for_each_safe(lh, lh_sf,
1019                                                    work_q) {
1020                                         scmd = list_entry(lh, struct
1021                                                           scsi_cmnd,
1022                                                           eh_entry);
1023                                         if (scmd->device == sdev)
1024                                                 scsi_eh_finish_cmd(scmd,
1025                                                                    done_q);
1026                                 }
1027                         }
1028                 } else {
1029                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1030                                                           " failed sdev:"
1031                                                           "0x%p\n",
1032                                                           current->comm,
1033                                                            sdev));
1034                 }
1035         }
1036
1037         return list_empty(work_q);
1038 }
1039
1040 /**
1041  * scsi_try_bus_reset - ask host to perform a bus reset
1042  * @scmd:       SCSI cmd to send bus reset.
1043  **/
1044 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
1045 {
1046         unsigned long flags;
1047         int rtn;
1048
1049         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1050                                           __FUNCTION__));
1051         scmd->owner = SCSI_OWNER_LOWLEVEL;
1052
1053         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1054                 return FAILED;
1055
1056         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1057
1058         if (rtn == SUCCESS) {
1059                 if (!scmd->device->host->hostt->skip_settle_delay)
1060                         ssleep(BUS_RESET_SETTLE_TIME);
1061                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1062                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1063                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1064         }
1065
1066         return rtn;
1067 }
1068
1069 /**
1070  * scsi_try_host_reset - ask host adapter to reset itself
1071  * @scmd:       SCSI cmd to send hsot reset.
1072  **/
1073 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1074 {
1075         unsigned long flags;
1076         int rtn;
1077
1078         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1079                                           __FUNCTION__));
1080         scmd->owner = SCSI_OWNER_LOWLEVEL;
1081
1082         if (!scmd->device->host->hostt->eh_host_reset_handler)
1083                 return FAILED;
1084
1085         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1086
1087         if (rtn == SUCCESS) {
1088                 if (!scmd->device->host->hostt->skip_settle_delay)
1089                         ssleep(HOST_RESET_SETTLE_TIME);
1090                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1091                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1092                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1093         }
1094
1095         return rtn;
1096 }
1097
1098 /**
1099  * scsi_eh_bus_reset - send a bus reset 
1100  * @shost:      scsi host being recovered.
1101  * @eh_done_q:  list_head for processed commands.
1102  **/
1103 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1104                              struct list_head *work_q,
1105                              struct list_head *done_q)
1106 {
1107         struct list_head *lh, *lh_sf;
1108         struct scsi_cmnd *scmd;
1109         struct scsi_cmnd *chan_scmd;
1110         unsigned int channel;
1111         int rtn;
1112
1113         /*
1114          * we really want to loop over the various channels, and do this on
1115          * a channel by channel basis.  we should also check to see if any
1116          * of the failed commands are on soft_reset devices, and if so, skip
1117          * the reset.  
1118          */
1119
1120         for (channel = 0; channel <= shost->max_channel; channel++) {
1121                 chan_scmd = NULL;
1122                 list_for_each_entry(scmd, work_q, eh_entry) {
1123                         if (channel == scmd->device->channel) {
1124                                 chan_scmd = scmd;
1125                                 break;
1126                                 /*
1127                                  * FIXME add back in some support for
1128                                  * soft_reset devices.
1129                                  */
1130                         }
1131                 }
1132
1133                 if (!chan_scmd)
1134                         continue;
1135                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1136                                                   " %d\n", current->comm,
1137                                                   channel));
1138                 rtn = scsi_try_bus_reset(chan_scmd);
1139                 if (rtn == SUCCESS) {
1140                         list_for_each_safe(lh, lh_sf, work_q) {
1141                                 scmd = list_entry(lh, struct scsi_cmnd,
1142                                                   eh_entry);
1143                                 if (channel == scmd->device->channel)
1144                                         if (!scsi_device_online(scmd->device) ||
1145                                             !scsi_eh_tur(scmd))
1146                                                 scsi_eh_finish_cmd(scmd,
1147                                                                    done_q);
1148                         }
1149                 } else {
1150                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1151                                                           " failed chan: %d\n",
1152                                                           current->comm,
1153                                                           channel));
1154                 }
1155         }
1156         return list_empty(work_q);
1157 }
1158
1159 /**
1160  * scsi_eh_host_reset - send a host reset 
1161  * @work_q:     list_head for processed commands.
1162  * @done_q:     list_head for processed commands.
1163  **/
1164 static int scsi_eh_host_reset(struct list_head *work_q,
1165                               struct list_head *done_q)
1166 {
1167         int rtn;
1168         struct list_head *lh, *lh_sf;
1169         struct scsi_cmnd *scmd;
1170
1171         if (!list_empty(work_q)) {
1172                 scmd = list_entry(work_q->next,
1173                                   struct scsi_cmnd, eh_entry);
1174
1175                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1176                                                   , current->comm));
1177
1178                 rtn = scsi_try_host_reset(scmd);
1179                 if (rtn == SUCCESS) {
1180                         list_for_each_safe(lh, lh_sf, work_q) {
1181                                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1182                                 if (!scsi_device_online(scmd->device) ||
1183                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1184                                     !scsi_eh_tur(scmd))
1185                                         scsi_eh_finish_cmd(scmd, done_q);
1186                         }
1187                 } else {
1188                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1189                                                           " failed\n",
1190                                                           current->comm));
1191                 }
1192         }
1193         return list_empty(work_q);
1194 }
1195
1196 /**
1197  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1198  * @work_q:     list_head for processed commands.
1199  * @done_q:     list_head for processed commands.
1200  *
1201  **/
1202 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1203                                   struct list_head *done_q)
1204 {
1205         struct list_head *lh, *lh_sf;
1206         struct scsi_cmnd *scmd;
1207
1208         list_for_each_safe(lh, lh_sf, work_q) {
1209                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1210                 printk(KERN_INFO "scsi: Device offlined - not"
1211                                 " ready after error recovery: host"
1212                                 " %d channel %d id %d lun %d\n",
1213                                 scmd->device->host->host_no,
1214                                 scmd->device->channel,
1215                                 scmd->device->id,
1216                                 scmd->device->lun);
1217                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1218                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD)) {
1219                         /*
1220                          * FIXME: Handle lost cmds.
1221                          */
1222                 }
1223                 scsi_eh_finish_cmd(scmd, done_q);
1224         }
1225         return;
1226 }
1227
1228 /**
1229  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1230  * @scmd:       SCSI cmd to examine.
1231  *
1232  * Notes:
1233  *    This is *only* called when we are examining the status after sending
1234  *    out the actual data command.  any commands that are queued for error
1235  *    recovery (e.g. test_unit_ready) do *not* come through here.
1236  *
1237  *    When this routine returns failed, it means the error handler thread
1238  *    is woken.  In cases where the error code indicates an error that
1239  *    doesn't require the error handler read (i.e. we don't need to
1240  *    abort/reset), this function should return SUCCESS.
1241  **/
1242 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1243 {
1244         int rtn;
1245
1246         /*
1247          * if the device is offline, then we clearly just pass the result back
1248          * up to the top level.
1249          */
1250         if (!scsi_device_online(scmd->device)) {
1251                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1252                                                   " as SUCCESS\n",
1253                                                   __FUNCTION__));
1254                 return SUCCESS;
1255         }
1256
1257         /*
1258          * first check the host byte, to see if there is anything in there
1259          * that would indicate what we need to do.
1260          */
1261         switch (host_byte(scmd->result)) {
1262         case DID_PASSTHROUGH:
1263                 /*
1264                  * no matter what, pass this through to the upper layer.
1265                  * nuke this special code so that it looks like we are saying
1266                  * did_ok.
1267                  */
1268                 scmd->result &= 0xff00ffff;
1269                 return SUCCESS;
1270         case DID_OK:
1271                 /*
1272                  * looks good.  drop through, and check the next byte.
1273                  */
1274                 break;
1275         case DID_NO_CONNECT:
1276         case DID_BAD_TARGET:
1277         case DID_ABORT:
1278                 /*
1279                  * note - this means that we just report the status back
1280                  * to the top level driver, not that we actually think
1281                  * that it indicates SUCCESS.
1282                  */
1283                 return SUCCESS;
1284                 /*
1285                  * when the low level driver returns did_soft_error,
1286                  * it is responsible for keeping an internal retry counter 
1287                  * in order to avoid endless loops (db)
1288                  *
1289                  * actually this is a bug in this function here.  we should
1290                  * be mindful of the maximum number of retries specified
1291                  * and not get stuck in a loop.
1292                  */
1293         case DID_SOFT_ERROR:
1294                 goto maybe_retry;
1295         case DID_IMM_RETRY:
1296                 return NEEDS_RETRY;
1297
1298         case DID_REQUEUE:
1299                 return ADD_TO_MLQUEUE;
1300
1301         case DID_ERROR:
1302                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1303                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1304                         /*
1305                          * execute reservation conflict processing code
1306                          * lower down
1307                          */
1308                         break;
1309                 /* fallthrough */
1310
1311         case DID_BUS_BUSY:
1312         case DID_PARITY:
1313                 goto maybe_retry;
1314         case DID_TIME_OUT:
1315                 /*
1316                  * when we scan the bus, we get timeout messages for
1317                  * these commands if there is no device available.
1318                  * other hosts report did_no_connect for the same thing.
1319                  */
1320                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1321                      scmd->cmnd[0] == INQUIRY)) {
1322                         return SUCCESS;
1323                 } else {
1324                         return FAILED;
1325                 }
1326         case DID_RESET:
1327                 return SUCCESS;
1328         default:
1329                 return FAILED;
1330         }
1331
1332         /*
1333          * next, check the message byte.
1334          */
1335         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1336                 return FAILED;
1337
1338         /*
1339          * check the status byte to see if this indicates anything special.
1340          */
1341         switch (status_byte(scmd->result)) {
1342         case QUEUE_FULL:
1343                 /*
1344                  * the case of trying to send too many commands to a
1345                  * tagged queueing device.
1346                  */
1347         case BUSY:
1348                 /*
1349                  * device can't talk to us at the moment.  Should only
1350                  * occur (SAM-3) when the task queue is empty, so will cause
1351                  * the empty queue handling to trigger a stall in the
1352                  * device.
1353                  */
1354                 return ADD_TO_MLQUEUE;
1355         case GOOD:
1356         case COMMAND_TERMINATED:
1357         case TASK_ABORTED:
1358                 return SUCCESS;
1359         case CHECK_CONDITION:
1360                 rtn = scsi_check_sense(scmd);
1361                 if (rtn == NEEDS_RETRY)
1362                         goto maybe_retry;
1363                 /* if rtn == FAILED, we have no sense information;
1364                  * returning FAILED will wake the error handler thread
1365                  * to collect the sense and redo the decide
1366                  * disposition */
1367                 return rtn;
1368         case CONDITION_GOOD:
1369         case INTERMEDIATE_GOOD:
1370         case INTERMEDIATE_C_GOOD:
1371         case ACA_ACTIVE:
1372                 /*
1373                  * who knows?  FIXME(eric)
1374                  */
1375                 return SUCCESS;
1376
1377         case RESERVATION_CONFLICT:
1378                 printk(KERN_INFO "scsi: reservation conflict: host"
1379                                 " %d channel %d id %d lun %d\n",
1380                        scmd->device->host->host_no, scmd->device->channel,
1381                        scmd->device->id, scmd->device->lun);
1382                 return SUCCESS; /* causes immediate i/o error */
1383         default:
1384                 return FAILED;
1385         }
1386         return FAILED;
1387
1388       maybe_retry:
1389
1390         /* we requeue for retry because the error was retryable, and
1391          * the request was not marked fast fail.  Note that above,
1392          * even if the request is marked fast fail, we still requeue
1393          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1394         if ((++scmd->retries) < scmd->allowed 
1395             && !blk_noretry_request(scmd->request)) {
1396                 return NEEDS_RETRY;
1397         } else {
1398                 /*
1399                  * no more retries - report this one back to upper level.
1400                  */
1401                 return SUCCESS;
1402         }
1403 }
1404
1405 /**
1406  * scsi_eh_lock_done - done function for eh door lock request
1407  * @scmd:       SCSI command block for the door lock request
1408  *
1409  * Notes:
1410  *      We completed the asynchronous door lock request, and it has either
1411  *      locked the door or failed.  We must free the command structures
1412  *      associated with this request.
1413  **/
1414 static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
1415 {
1416         struct scsi_request *sreq = scmd->sc_request;
1417
1418         scsi_release_request(sreq);
1419 }
1420
1421
1422 /**
1423  * scsi_eh_lock_door - Prevent medium removal for the specified device
1424  * @sdev:       SCSI device to prevent medium removal
1425  *
1426  * Locking:
1427  *      We must be called from process context; scsi_allocate_request()
1428  *      may sleep.
1429  *
1430  * Notes:
1431  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1432  *      head of the devices request queue, and continue.
1433  *
1434  * Bugs:
1435  *      scsi_allocate_request() may sleep waiting for existing requests to
1436  *      be processed.  However, since we haven't kicked off any request
1437  *      processing for this host, this may deadlock.
1438  *
1439  *      If scsi_allocate_request() fails for what ever reason, we
1440  *      completely forget to lock the door.
1441  **/
1442 static void scsi_eh_lock_door(struct scsi_device *sdev)
1443 {
1444         struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
1445
1446         if (unlikely(!sreq)) {
1447                 printk(KERN_ERR "%s: request allocate failed,"
1448                        "prevent media removal cmd not sent\n", __FUNCTION__);
1449                 return;
1450         }
1451
1452         sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1453         sreq->sr_cmnd[1] = 0;
1454         sreq->sr_cmnd[2] = 0;
1455         sreq->sr_cmnd[3] = 0;
1456         sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
1457         sreq->sr_cmnd[5] = 0;
1458         sreq->sr_data_direction = DMA_NONE;
1459         sreq->sr_bufflen = 0;
1460         sreq->sr_buffer = NULL;
1461         sreq->sr_allowed = 5;
1462         sreq->sr_done = scsi_eh_lock_done;
1463         sreq->sr_timeout_per_command = 10 * HZ;
1464         sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
1465
1466         scsi_insert_special_req(sreq, 1);
1467 }
1468
1469
1470 /**
1471  * scsi_restart_operations - restart io operations to the specified host.
1472  * @shost:      Host we are restarting.
1473  *
1474  * Notes:
1475  *    When we entered the error handler, we blocked all further i/o to
1476  *    this device.  we need to 'reverse' this process.
1477  **/
1478 static void scsi_restart_operations(struct Scsi_Host *shost)
1479 {
1480         struct scsi_device *sdev;
1481
1482         /*
1483          * If the door was locked, we need to insert a door lock request
1484          * onto the head of the SCSI request queue for the device.  There
1485          * is no point trying to lock the door of an off-line device.
1486          */
1487         shost_for_each_device(sdev, shost) {
1488                 if (scsi_device_online(sdev) && sdev->locked)
1489                         scsi_eh_lock_door(sdev);
1490         }
1491
1492         /*
1493          * next free up anything directly waiting upon the host.  this
1494          * will be requests for character device operations, and also for
1495          * ioctls to queued block devices.
1496          */
1497         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1498                                           __FUNCTION__));
1499
1500         clear_bit(SHOST_RECOVERY, &shost->shost_state);
1501
1502         wake_up(&shost->host_wait);
1503
1504         /*
1505          * finally we need to re-initiate requests that may be pending.  we will
1506          * have had everything blocked while error handling is taking place, and
1507          * now that error recovery is done, we will need to ensure that these
1508          * requests are started.
1509          */
1510         scsi_run_host_queues(shost);
1511 }
1512
1513 /**
1514  * scsi_eh_ready_devs - check device ready state and recover if not.
1515  * @shost:      host to be recovered.
1516  * @eh_done_q:  list_head for processed commands.
1517  *
1518  **/
1519 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1520                                struct list_head *work_q,
1521                                struct list_head *done_q)
1522 {
1523         if (!scsi_eh_stu(shost, work_q, done_q))
1524                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1525                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1526                                 if (!scsi_eh_host_reset(work_q, done_q))
1527                                         scsi_eh_offline_sdevs(work_q, done_q);
1528 }
1529
1530 /**
1531  * scsi_eh_flush_done_q - finish processed commands or retry them.
1532  * @done_q:     list_head of processed commands.
1533  *
1534  **/
1535 static void scsi_eh_flush_done_q(struct list_head *done_q)
1536 {
1537         struct list_head *lh, *lh_sf;
1538         struct scsi_cmnd *scmd;
1539
1540         list_for_each_safe(lh, lh_sf, done_q) {
1541                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1542                 list_del_init(lh);
1543                 if (scsi_device_online(scmd->device) &&
1544                     !blk_noretry_request(scmd->request) &&
1545                     (++scmd->retries < scmd->allowed)) {
1546                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1547                                                           " retry cmd: %p\n",
1548                                                           current->comm,
1549                                                           scmd));
1550                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1551                 } else {
1552                         /*
1553                          * If just we got sense for the device (called
1554                          * scsi_eh_get_sense), scmd->result is already
1555                          * set, do not set DRIVER_TIMEOUT.
1556                          */
1557                         if (!scmd->result)
1558                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1559                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1560                                                         " cmd: %p\n",
1561                                                         current->comm, scmd));
1562                         scsi_finish_command(scmd);
1563                 }
1564         }
1565 }
1566
1567 /**
1568  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1569  * @shost:      Host to unjam.
1570  *
1571  * Notes:
1572  *    When we come in here, we *know* that all commands on the bus have
1573  *    either completed, failed or timed out.  we also know that no further
1574  *    commands are being sent to the host, so things are relatively quiet
1575  *    and we have freedom to fiddle with things as we wish.
1576  *
1577  *    This is only the *default* implementation.  it is possible for
1578  *    individual drivers to supply their own version of this function, and
1579  *    if the maintainer wishes to do this, it is strongly suggested that
1580  *    this function be taken as a template and modified.  this function
1581  *    was designed to correctly handle problems for about 95% of the
1582  *    different cases out there, and it should always provide at least a
1583  *    reasonable amount of error recovery.
1584  *
1585  *    Any command marked 'failed' or 'timeout' must eventually have
1586  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1587  *    here, so when we restart the host after we return it should have an
1588  *    empty queue.
1589  **/
1590 static void scsi_unjam_host(struct Scsi_Host *shost)
1591 {
1592         unsigned long flags;
1593         LIST_HEAD(eh_work_q);
1594         LIST_HEAD(eh_done_q);
1595
1596         spin_lock_irqsave(shost->host_lock, flags);
1597         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1598         spin_unlock_irqrestore(shost->host_lock, flags);
1599
1600         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1601
1602         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1603                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1604                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1605
1606         scsi_eh_flush_done_q(&eh_done_q);
1607 }
1608
1609 /**
1610  * scsi_error_handler - Handle errors/timeouts of SCSI cmds.
1611  * @data:       Host for which we are running.
1612  *
1613  * Notes:
1614  *    This is always run in the context of a kernel thread.  The idea is
1615  *    that we start this thing up when the kernel starts up (one per host
1616  *    that we detect), and it immediately goes to sleep and waits for some
1617  *    event (i.e. failure).  When this takes place, we have the job of
1618  *    trying to unjam the bus and restarting things.
1619  **/
1620 int scsi_error_handler(void *data)
1621 {
1622         struct Scsi_Host *shost = (struct Scsi_Host *) data;
1623         int rtn;
1624         DECLARE_MUTEX_LOCKED(sem);
1625
1626         /*
1627          *    Flush resources
1628          */
1629
1630         daemonize("scsi_eh_%d", shost->host_no);
1631
1632         current->flags |= PF_NOFREEZE;
1633
1634         shost->eh_wait = &sem;
1635         shost->ehandler = current;
1636
1637         /*
1638          * Wake up the thread that created us.
1639          */
1640         SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
1641                                           " scsi_eh_%d\n",shost->host_no));
1642
1643         complete(shost->eh_notify);
1644
1645         while (1) {
1646                 /*
1647                  * If we get a signal, it means we are supposed to go
1648                  * away and die.  This typically happens if the user is
1649                  * trying to unload a module.
1650                  */
1651                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1652                                                   " scsi_eh_%d"
1653                                                   " sleeping\n",shost->host_no));
1654
1655                 /*
1656                  * Note - we always use down_interruptible with the semaphore
1657                  * even if the module was loaded as part of the kernel.  The
1658                  * reason is that down() will cause this thread to be counted
1659                  * in the load average as a running process, and down
1660                  * interruptible doesn't.  Given that we need to allow this
1661                  * thread to die if the driver was loaded as a module, using
1662                  * semaphores isn't unreasonable.
1663                  */
1664                 down_interruptible(&sem);
1665                 if (shost->eh_kill)
1666                         break;
1667
1668                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1669                                                   " scsi_eh_%d waking"
1670                                                   " up\n",shost->host_no));
1671
1672                 shost->eh_active = 1;
1673
1674                 /*
1675                  * We have a host that is failing for some reason.  Figure out
1676                  * what we need to do to get it up and online again (if we can).
1677                  * If we fail, we end up taking the thing offline.
1678                  */
1679                 if (shost->hostt->eh_strategy_handler) 
1680                         rtn = shost->hostt->eh_strategy_handler(shost);
1681                 else
1682                         scsi_unjam_host(shost);
1683
1684                 shost->eh_active = 0;
1685
1686                 /*
1687                  * Note - if the above fails completely, the action is to take
1688                  * individual devices offline and flush the queue of any
1689                  * outstanding requests that may have been pending.  When we
1690                  * restart, we restart any I/O to any other devices on the bus
1691                  * which are still online.
1692                  */
1693                 scsi_restart_operations(shost);
1694
1695         }
1696
1697         SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
1698                                           " exiting\n",shost->host_no));
1699
1700         /*
1701          * Make sure that nobody tries to wake us up again.
1702          */
1703         shost->eh_wait = NULL;
1704
1705         /*
1706          * Knock this down too.  From this point on, the host is flying
1707          * without a pilot.  If this is because the module is being unloaded,
1708          * that's fine.  If the user sent a signal to this thing, we are
1709          * potentially in real danger.
1710          */
1711         shost->eh_active = 0;
1712         shost->ehandler = NULL;
1713
1714         /*
1715          * If anyone is waiting for us to exit (i.e. someone trying to unload
1716          * a driver), then wake up that process to let them know we are on
1717          * the way out the door.
1718          */
1719         complete_and_exit(shost->eh_notify, 0);
1720         return 0;
1721 }
1722
1723 /*
1724  * Function:    scsi_report_bus_reset()
1725  *
1726  * Purpose:     Utility function used by low-level drivers to report that
1727  *              they have observed a bus reset on the bus being handled.
1728  *
1729  * Arguments:   shost       - Host in question
1730  *              channel     - channel on which reset was observed.
1731  *
1732  * Returns:     Nothing
1733  *
1734  * Lock status: Host lock must be held.
1735  *
1736  * Notes:       This only needs to be called if the reset is one which
1737  *              originates from an unknown location.  Resets originated
1738  *              by the mid-level itself don't need to call this, but there
1739  *              should be no harm.
1740  *
1741  *              The main purpose of this is to make sure that a CHECK_CONDITION
1742  *              is properly treated.
1743  */
1744 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1745 {
1746         struct scsi_device *sdev;
1747
1748         __shost_for_each_device(sdev, shost) {
1749                 if (channel == sdev->channel) {
1750                         sdev->was_reset = 1;
1751                         sdev->expecting_cc_ua = 1;
1752                 }
1753         }
1754 }
1755 EXPORT_SYMBOL(scsi_report_bus_reset);
1756
1757 /*
1758  * Function:    scsi_report_device_reset()
1759  *
1760  * Purpose:     Utility function used by low-level drivers to report that
1761  *              they have observed a device reset on the device being handled.
1762  *
1763  * Arguments:   shost       - Host in question
1764  *              channel     - channel on which reset was observed
1765  *              target      - target on which reset was observed
1766  *
1767  * Returns:     Nothing
1768  *
1769  * Lock status: Host lock must be held
1770  *
1771  * Notes:       This only needs to be called if the reset is one which
1772  *              originates from an unknown location.  Resets originated
1773  *              by the mid-level itself don't need to call this, but there
1774  *              should be no harm.
1775  *
1776  *              The main purpose of this is to make sure that a CHECK_CONDITION
1777  *              is properly treated.
1778  */
1779 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1780 {
1781         struct scsi_device *sdev;
1782
1783         __shost_for_each_device(sdev, shost) {
1784                 if (channel == sdev->channel &&
1785                     target == sdev->id) {
1786                         sdev->was_reset = 1;
1787                         sdev->expecting_cc_ua = 1;
1788                 }
1789         }
1790 }
1791 EXPORT_SYMBOL(scsi_report_device_reset);
1792
1793 static void
1794 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1795 {
1796 }
1797
1798 /*
1799  * Function:    scsi_reset_provider
1800  *
1801  * Purpose:     Send requested reset to a bus or device at any phase.
1802  *
1803  * Arguments:   device  - device to send reset to
1804  *              flag - reset type (see scsi.h)
1805  *
1806  * Returns:     SUCCESS/FAILURE.
1807  *
1808  * Notes:       This is used by the SCSI Generic driver to provide
1809  *              Bus/Device reset capability.
1810  */
1811 int
1812 scsi_reset_provider(struct scsi_device *dev, int flag)
1813 {
1814         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1815         struct request req;
1816         int rtn;
1817
1818         scmd->request = &req;
1819         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1820         scmd->request->rq_status        = RQ_SCSI_BUSY;
1821         scmd->state                     = SCSI_STATE_INITIALIZING;
1822         scmd->owner                     = SCSI_OWNER_MIDLEVEL;
1823     
1824         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1825     
1826         scmd->scsi_done         = scsi_reset_provider_done_command;
1827         scmd->done                      = NULL;
1828         scmd->buffer                    = NULL;
1829         scmd->bufflen                   = 0;
1830         scmd->request_buffer            = NULL;
1831         scmd->request_bufflen           = 0;
1832         scmd->abort_reason              = DID_ABORT;
1833
1834         scmd->cmd_len                   = 0;
1835
1836         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1837         scmd->sc_request                = NULL;
1838         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1839
1840         init_timer(&scmd->eh_timeout);
1841
1842         /*
1843          * Sometimes the command can get back into the timer chain,
1844          * so use the pid as an identifier.
1845          */
1846         scmd->pid                       = 0;
1847
1848         switch (flag) {
1849         case SCSI_TRY_RESET_DEVICE:
1850                 rtn = scsi_try_bus_device_reset(scmd);
1851                 if (rtn == SUCCESS)
1852                         break;
1853                 /* FALLTHROUGH */
1854         case SCSI_TRY_RESET_BUS:
1855                 rtn = scsi_try_bus_reset(scmd);
1856                 if (rtn == SUCCESS)
1857                         break;
1858                 /* FALLTHROUGH */
1859         case SCSI_TRY_RESET_HOST:
1860                 rtn = scsi_try_host_reset(scmd);
1861                 break;
1862         default:
1863                 rtn = FAILED;
1864         }
1865
1866         scsi_next_command(scmd);
1867         return rtn;
1868 }
1869 EXPORT_SYMBOL(scsi_reset_provider);
1870
1871 /**
1872  * scsi_normalize_sense - normalize main elements from either fixed or
1873  *                      descriptor sense data format into a common format.
1874  *
1875  * @sense_buffer:       byte array containing sense data returned by device
1876  * @sb_len:             number of valid bytes in sense_buffer
1877  * @sshdr:              pointer to instance of structure that common
1878  *                      elements are written to.
1879  *
1880  * Notes:
1881  *      The "main elements" from sense data are: response_code, sense_key,
1882  *      asc, ascq and additional_length (only for descriptor format).
1883  *
1884  *      Typically this function can be called after a device has
1885  *      responded to a SCSI command with the CHECK_CONDITION status.
1886  *
1887  * Return value:
1888  *      1 if valid sense data information found, else 0;
1889  **/
1890 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1891                          struct scsi_sense_hdr *sshdr)
1892 {
1893         if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
1894                 return 0;
1895
1896         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1897
1898         sshdr->response_code = (sense_buffer[0] & 0x7f);
1899         if (sshdr->response_code >= 0x72) {
1900                 /*
1901                  * descriptor format
1902                  */
1903                 if (sb_len > 1)
1904                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1905                 if (sb_len > 2)
1906                         sshdr->asc = sense_buffer[2];
1907                 if (sb_len > 3)
1908                         sshdr->ascq = sense_buffer[3];
1909                 if (sb_len > 7)
1910                         sshdr->additional_length = sense_buffer[7];
1911         } else {
1912                 /* 
1913                  * fixed format
1914                  */
1915                 if (sb_len > 2)
1916                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1917                 if (sb_len > 7) {
1918                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1919                                          sb_len : (sense_buffer[7] + 8);
1920                         if (sb_len > 12)
1921                                 sshdr->asc = sense_buffer[12];
1922                         if (sb_len > 13)
1923                                 sshdr->ascq = sense_buffer[13];
1924                 }
1925         }
1926
1927         return 1;
1928 }
1929 EXPORT_SYMBOL(scsi_normalize_sense);
1930
1931 int scsi_request_normalize_sense(struct scsi_request *sreq,
1932                                  struct scsi_sense_hdr *sshdr)
1933 {
1934         return scsi_normalize_sense(sreq->sr_sense_buffer,
1935                         sizeof(sreq->sr_sense_buffer), sshdr);
1936 }
1937 EXPORT_SYMBOL(scsi_request_normalize_sense);
1938
1939 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1940                                  struct scsi_sense_hdr *sshdr)
1941 {
1942         return scsi_normalize_sense(cmd->sense_buffer,
1943                         sizeof(cmd->sense_buffer), sshdr);
1944 }
1945 EXPORT_SYMBOL(scsi_command_normalize_sense);
1946
1947 /**
1948  * scsi_sense_desc_find - search for a given descriptor type in
1949  *                      descriptor sense data format.
1950  *
1951  * @sense_buffer:       byte array of descriptor format sense data
1952  * @sb_len:             number of valid bytes in sense_buffer
1953  * @desc_type:          value of descriptor type to find
1954  *                      (e.g. 0 -> information)
1955  *
1956  * Notes:
1957  *      only valid when sense data is in descriptor format
1958  *
1959  * Return value:
1960  *      pointer to start of (first) descriptor if found else NULL
1961  **/
1962 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1963                                 int desc_type)
1964 {
1965         int add_sen_len, add_len, desc_len, k;
1966         const u8 * descp;
1967
1968         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1969                 return NULL;
1970         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1971                 return NULL;
1972         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1973                         add_sen_len : (sb_len - 8);
1974         descp = &sense_buffer[8];
1975         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1976                 descp += desc_len;
1977                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1978                 desc_len = add_len + 2;
1979                 if (descp[0] == desc_type)
1980                         return descp;
1981                 if (add_len < 0) // short descriptor ??
1982                         break;
1983         }
1984         return NULL;
1985 }
1986 EXPORT_SYMBOL(scsi_sense_desc_find);
1987
1988 /**
1989  * scsi_get_sense_info_fld - attempts to get information field from
1990  *                      sense data (either fixed or descriptor format)
1991  *
1992  * @sense_buffer:       byte array of sense data
1993  * @sb_len:             number of valid bytes in sense_buffer
1994  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1995  *                      field will be placed if found.
1996  *
1997  * Return value:
1998  *      1 if information field found, 0 if not found.
1999  **/
2000 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2001                             u64 * info_out)
2002 {
2003         int j;
2004         const u8 * ucp;
2005         u64 ull;
2006
2007         if (sb_len < 7)
2008                 return 0;
2009         switch (sense_buffer[0] & 0x7f) {
2010         case 0x70:
2011         case 0x71:
2012                 if (sense_buffer[0] & 0x80) {
2013                         *info_out = (sense_buffer[3] << 24) +
2014                                     (sense_buffer[4] << 16) +
2015                                     (sense_buffer[5] << 8) + sense_buffer[6];
2016                         return 1;
2017                 } else
2018                         return 0;
2019         case 0x72:
2020         case 0x73:
2021                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2022                                            0 /* info desc */);
2023                 if (ucp && (0xa == ucp[1])) {
2024                         ull = 0;
2025                         for (j = 0; j < 8; ++j) {
2026                                 if (j > 0)
2027                                         ull <<= 8;
2028                                 ull |= ucp[4 + j];
2029                         }
2030                         *info_out = ull;
2031                         return 1;
2032                 } else
2033                         return 0;
2034         default:
2035                 return 0;
2036         }
2037 }
2038 EXPORT_SYMBOL(scsi_get_sense_info_fld);