[PATCH] scsi: remove meaningless scsi_cmnd->serial_number_at_timeout field
[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/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         if (scmd->device->host->eh_action)
438                 up(scmd->device->host->eh_action);
439 }
440
441 /**
442  * scsi_eh_done - Completion function for error handling.
443  * @scmd:       Cmd that is done.
444  **/
445 static void scsi_eh_done(struct scsi_cmnd *scmd)
446 {
447         /*
448          * if the timeout handler is already running, then just set the
449          * flag which says we finished late, and return.  we have no
450          * way of stopping the timeout handler from running, so we must
451          * always defer to it.
452          */
453         if (del_timer(&scmd->eh_timeout)) {
454                 scmd->request->rq_status = RQ_SCSI_DONE;
455                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
456
457                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
458                                            __FUNCTION__, scmd, scmd->result));
459
460                 if (scmd->device->host->eh_action)
461                         up(scmd->device->host->eh_action);
462         }
463 }
464
465 /**
466  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
467  * @scmd:       SCSI Cmd to send.
468  * @timeout:    Timeout for cmd.
469  *
470  * Notes:
471  *    The initialization of the structures is quite a bit different in
472  *    this case, and furthermore, there is a different completion handler
473  *    vs scsi_dispatch_cmd.
474  * Return value:
475  *    SUCCESS or FAILED or NEEDS_RETRY
476  **/
477 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
478 {
479         struct Scsi_Host *host = scmd->device->host;
480         DECLARE_MUTEX_LOCKED(sem);
481         unsigned long flags;
482         int rtn = SUCCESS;
483
484         /*
485          * we will use a queued command if possible, otherwise we will
486          * emulate the queuing and calling of completion function ourselves.
487          */
488         scmd->owner = SCSI_OWNER_LOWLEVEL;
489
490         if (scmd->device->scsi_level <= SCSI_2)
491                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
492                         (scmd->device->lun << 5 & 0xe0);
493
494         scsi_add_timer(scmd, timeout, scsi_eh_times_out);
495
496         /*
497          * set up the semaphore so we wait for the command to complete.
498          */
499         scmd->device->host->eh_action = &sem;
500         scmd->request->rq_status = RQ_SCSI_BUSY;
501
502         spin_lock_irqsave(scmd->device->host->host_lock, flags);
503         scsi_log_send(scmd);
504         host->hostt->queuecommand(scmd, scsi_eh_done);
505         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
506
507         down(&sem);
508         scsi_log_completion(scmd, SUCCESS);
509
510         scmd->device->host->eh_action = NULL;
511
512         /*
513          * see if timeout.  if so, tell the host to forget about it.
514          * in other words, we don't want a callback any more.
515          */
516         if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
517                 scsi_eh_eflags_clr(scmd,  SCSI_EH_REC_TIMEOUT);
518                 scmd->owner = SCSI_OWNER_LOWLEVEL;
519
520                 /*
521                  * as far as the low level driver is
522                  * concerned, this command is still active, so
523                  * we must give the low level driver a chance
524                  * to abort it. (db) 
525                  *
526                  * FIXME(eric) - we are not tracking whether we could
527                  * abort a timed out command or not.  not sure how
528                  * we should treat them differently anyways.
529                  */
530                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
531                 if (scmd->device->host->hostt->eh_abort_handler)
532                         scmd->device->host->hostt->eh_abort_handler(scmd);
533                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
534                         
535                 scmd->request->rq_status = RQ_SCSI_DONE;
536                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
537                         
538                 rtn = FAILED;
539         }
540
541         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
542                                           __FUNCTION__, scmd, rtn));
543
544         /*
545          * now examine the actual status codes to see whether the command
546          * actually did complete normally.
547          */
548         if (rtn == SUCCESS) {
549                 rtn = scsi_eh_completed_normally(scmd);
550                 SCSI_LOG_ERROR_RECOVERY(3,
551                         printk("%s: scsi_eh_completed_normally %x\n",
552                                __FUNCTION__, rtn));
553                 switch (rtn) {
554                 case SUCCESS:
555                 case NEEDS_RETRY:
556                 case FAILED:
557                         break;
558                 default:
559                         rtn = FAILED;
560                         break;
561                 }
562         }
563
564         return rtn;
565 }
566
567 /**
568  * scsi_request_sense - Request sense data from a particular target.
569  * @scmd:       SCSI cmd for request sense.
570  *
571  * Notes:
572  *    Some hosts automatically obtain this information, others require
573  *    that we obtain it on our own. This function will *not* return until
574  *    the command either times out, or it completes.
575  **/
576 static int scsi_request_sense(struct scsi_cmnd *scmd)
577 {
578         static unsigned char generic_sense[6] =
579         {REQUEST_SENSE, 0, 0, 0, 252, 0};
580         unsigned char *scsi_result;
581         int saved_result;
582         int rtn;
583
584         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
585
586         scsi_result = kmalloc(252, GFP_ATOMIC | (scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0);
587
588
589         if (unlikely(!scsi_result)) {
590                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
591                        __FUNCTION__);
592                 return FAILED;
593         }
594
595         /*
596          * zero the sense buffer.  some host adapters automatically always
597          * request sense, so it is not a good idea that
598          * scmd->request_buffer and scmd->sense_buffer point to the same
599          * address (db).  0 is not a valid sense code. 
600          */
601         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
602         memset(scsi_result, 0, 252);
603
604         saved_result = scmd->result;
605         scmd->request_buffer = scsi_result;
606         scmd->request_bufflen = 252;
607         scmd->use_sg = 0;
608         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
609         scmd->sc_data_direction = DMA_FROM_DEVICE;
610         scmd->underflow = 0;
611
612         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
613
614         /* last chance to have valid sense data */
615         if(!SCSI_SENSE_VALID(scmd)) {
616                 memcpy(scmd->sense_buffer, scmd->request_buffer,
617                        sizeof(scmd->sense_buffer));
618         }
619
620         kfree(scsi_result);
621
622         /*
623          * when we eventually call scsi_finish, we really wish to complete
624          * the original request, so let's restore the original data. (db)
625          */
626         scsi_setup_cmd_retry(scmd);
627         scmd->result = saved_result;
628         return rtn;
629 }
630
631 /**
632  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
633  * @scmd:       Original SCSI cmd that eh has finished.
634  * @done_q:     Queue for processed commands.
635  *
636  * Notes:
637  *    We don't want to use the normal command completion while we are are
638  *    still handling errors - it may cause other commands to be queued,
639  *    and that would disturb what we are doing.  thus we really want to
640  *    keep a list of pending commands for final completion, and once we
641  *    are ready to leave error handling we handle completion for real.
642  **/
643 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
644                                struct list_head *done_q)
645 {
646         scmd->device->host->host_failed--;
647         scmd->state = SCSI_STATE_BHQUEUE;
648
649         scsi_eh_eflags_clr_all(scmd);
650
651         /*
652          * set this back so that the upper level can correctly free up
653          * things.
654          */
655         scsi_setup_cmd_retry(scmd);
656         list_move_tail(&scmd->eh_entry, done_q);
657 }
658
659 /**
660  * scsi_eh_get_sense - Get device sense data.
661  * @work_q:     Queue of commands to process.
662  * @done_q:     Queue of proccessed commands..
663  *
664  * Description:
665  *    See if we need to request sense information.  if so, then get it
666  *    now, so we have a better idea of what to do.  
667  *
668  * Notes:
669  *    This has the unfortunate side effect that if a shost adapter does
670  *    not automatically request sense information, that we end up shutting
671  *    it down before we request it.
672  *
673  *    All drivers should request sense information internally these days,
674  *    so for now all I have to say is tough noogies if you end up in here.
675  *
676  *    XXX: Long term this code should go away, but that needs an audit of
677  *         all LLDDs first.
678  **/
679 static int scsi_eh_get_sense(struct list_head *work_q,
680                              struct list_head *done_q)
681 {
682         struct list_head *lh, *lh_sf;
683         struct scsi_cmnd *scmd;
684         int rtn;
685
686         list_for_each_safe(lh, lh_sf, work_q) {
687                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
688                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
689                     SCSI_SENSE_VALID(scmd))
690                         continue;
691
692                 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
693                                                   " for id: %d\n",
694                                                   current->comm,
695                                                   scmd->device->id));
696                 rtn = scsi_request_sense(scmd);
697                 if (rtn != SUCCESS)
698                         continue;
699
700                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
701                                                   " result %x\n", scmd,
702                                                   scmd->result));
703                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
704
705                 rtn = scsi_decide_disposition(scmd);
706
707                 /*
708                  * if the result was normal, then just pass it along to the
709                  * upper level.
710                  */
711                 if (rtn == SUCCESS)
712                         /* we don't want this command reissued, just
713                          * finished with the sense data, so set
714                          * retries to the max allowed to ensure it
715                          * won't get reissued */
716                         scmd->retries = scmd->allowed;
717                 else if (rtn != NEEDS_RETRY)
718                         continue;
719
720                 scsi_eh_finish_cmd(scmd, done_q);
721         }
722
723         return list_empty(work_q);
724 }
725
726 /**
727  * scsi_try_to_abort_cmd - Ask host to abort a running command.
728  * @scmd:       SCSI cmd to abort from Lower Level.
729  *
730  * Notes:
731  *    This function will not return until the user's completion function
732  *    has been called.  there is no timeout on this operation.  if the
733  *    author of the low-level driver wishes this operation to be timed,
734  *    they can provide this facility themselves.  helper functions in
735  *    scsi_error.c can be supplied to make this easier to do.
736  **/
737 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
738 {
739         unsigned long flags;
740         int rtn = FAILED;
741
742         if (!scmd->device->host->hostt->eh_abort_handler)
743                 return rtn;
744
745         /*
746          * scsi_done was called just after the command timed out and before
747          * we had a chance to process it. (db)
748          */
749         if (scmd->serial_number == 0)
750                 return SUCCESS;
751
752         scmd->owner = SCSI_OWNER_LOWLEVEL;
753
754         spin_lock_irqsave(scmd->device->host->host_lock, flags);
755         rtn = scmd->device->host->hostt->eh_abort_handler(scmd);
756         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
757
758         return rtn;
759 }
760
761 /**
762  * scsi_eh_tur - Send TUR to device.
763  * @scmd:       Scsi cmd to send TUR
764  *
765  * Return value:
766  *    0 - Device is ready. 1 - Device NOT ready.
767  **/
768 static int scsi_eh_tur(struct scsi_cmnd *scmd)
769 {
770         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
771         int retry_cnt = 1, rtn;
772
773 retry_tur:
774         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
775
776         /*
777          * zero the sense buffer.  the scsi spec mandates that any
778          * untransferred sense data should be interpreted as being zero.
779          */
780         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
781
782         scmd->request_buffer = NULL;
783         scmd->request_bufflen = 0;
784         scmd->use_sg = 0;
785         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
786         scmd->underflow = 0;
787         scmd->sc_data_direction = DMA_NONE;
788
789         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
790
791         /*
792          * when we eventually call scsi_finish, we really wish to complete
793          * the original request, so let's restore the original data. (db)
794          */
795         scsi_setup_cmd_retry(scmd);
796
797         /*
798          * hey, we are done.  let's look to see what happened.
799          */
800         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
801                 __FUNCTION__, scmd, rtn));
802         if (rtn == SUCCESS)
803                 return 0;
804         else if (rtn == NEEDS_RETRY)
805                 if (retry_cnt--)
806                         goto retry_tur;
807         return 1;
808 }
809
810 /**
811  * scsi_eh_abort_cmds - abort canceled commands.
812  * @shost:      scsi host being recovered.
813  * @eh_done_q:  list_head for processed commands.
814  *
815  * Decription:
816  *    Try and see whether or not it makes sense to try and abort the
817  *    running command.  this only works out to be the case if we have one
818  *    command that has timed out.  if the command simply failed, it makes
819  *    no sense to try and abort the command, since as far as the shost
820  *    adapter is concerned, it isn't running.
821  **/
822 static int scsi_eh_abort_cmds(struct list_head *work_q,
823                               struct list_head *done_q)
824 {
825         struct list_head *lh, *lh_sf;
826         struct scsi_cmnd *scmd;
827         int rtn;
828
829         list_for_each_safe(lh, lh_sf, work_q) {
830                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
831                 if (!scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD))
832                         continue;
833                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
834                                                   "0x%p\n", current->comm,
835                                                   scmd));
836                 rtn = scsi_try_to_abort_cmd(scmd);
837                 if (rtn == SUCCESS) {
838                         scsi_eh_eflags_clr(scmd,  SCSI_EH_CANCEL_CMD);
839                         if (!scsi_device_online(scmd->device) ||
840                             !scsi_eh_tur(scmd)) {
841                                 scsi_eh_finish_cmd(scmd, done_q);
842                         }
843                                 
844                 } else
845                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
846                                                           " cmd failed:"
847                                                           "0x%p\n",
848                                                           current->comm,
849                                                           scmd));
850         }
851
852         return list_empty(work_q);
853 }
854
855 /**
856  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
857  * @scmd:       SCSI cmd used to send BDR       
858  *
859  * Notes:
860  *    There is no timeout for this operation.  if this operation is
861  *    unreliable for a given host, then the host itself needs to put a
862  *    timer on it, and set the host back to a consistent state prior to
863  *    returning.
864  **/
865 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
866 {
867         unsigned long flags;
868         int rtn = FAILED;
869
870         if (!scmd->device->host->hostt->eh_device_reset_handler)
871                 return rtn;
872
873         scmd->owner = SCSI_OWNER_LOWLEVEL;
874
875         spin_lock_irqsave(scmd->device->host->host_lock, flags);
876         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
877         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
878
879         if (rtn == SUCCESS) {
880                 scmd->device->was_reset = 1;
881                 scmd->device->expecting_cc_ua = 1;
882         }
883
884         return rtn;
885 }
886
887 /**
888  * scsi_eh_try_stu - Send START_UNIT to device.
889  * @scmd:       Scsi cmd to send START_UNIT
890  *
891  * Return value:
892  *    0 - Device is ready. 1 - Device NOT ready.
893  **/
894 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
895 {
896         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
897         int rtn;
898
899         if (!scmd->device->allow_restart)
900                 return 1;
901
902         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
903
904         /*
905          * zero the sense buffer.  the scsi spec mandates that any
906          * untransferred sense data should be interpreted as being zero.
907          */
908         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
909
910         scmd->request_buffer = NULL;
911         scmd->request_bufflen = 0;
912         scmd->use_sg = 0;
913         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
914         scmd->underflow = 0;
915         scmd->sc_data_direction = DMA_NONE;
916
917         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
918
919         /*
920          * when we eventually call scsi_finish, we really wish to complete
921          * the original request, so let's restore the original data. (db)
922          */
923         scsi_setup_cmd_retry(scmd);
924
925         /*
926          * hey, we are done.  let's look to see what happened.
927          */
928         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
929                 __FUNCTION__, scmd, rtn));
930         if (rtn == SUCCESS)
931                 return 0;
932         return 1;
933 }
934
935  /**
936  * scsi_eh_stu - send START_UNIT if needed
937  * @shost:      scsi host being recovered.
938  * @eh_done_q:  list_head for processed commands.
939  *
940  * Notes:
941  *    If commands are failing due to not ready, initializing command required,
942  *      try revalidating the device, which will end up sending a start unit. 
943  **/
944 static int scsi_eh_stu(struct Scsi_Host *shost,
945                               struct list_head *work_q,
946                               struct list_head *done_q)
947 {
948         struct list_head *lh, *lh_sf;
949         struct scsi_cmnd *scmd, *stu_scmd;
950         struct scsi_device *sdev;
951
952         shost_for_each_device(sdev, shost) {
953                 stu_scmd = NULL;
954                 list_for_each_entry(scmd, work_q, eh_entry)
955                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
956                             scsi_check_sense(scmd) == FAILED ) {
957                                 stu_scmd = scmd;
958                                 break;
959                         }
960
961                 if (!stu_scmd)
962                         continue;
963
964                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
965                                                   " 0x%p\n", current->comm, sdev));
966
967                 if (!scsi_eh_try_stu(stu_scmd)) {
968                         if (!scsi_device_online(sdev) ||
969                             !scsi_eh_tur(stu_scmd)) {
970                                 list_for_each_safe(lh, lh_sf, work_q) {
971                                         scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
972                                         if (scmd->device == sdev)
973                                                 scsi_eh_finish_cmd(scmd, done_q);
974                                 }
975                         }
976                 } else {
977                         SCSI_LOG_ERROR_RECOVERY(3,
978                                                 printk("%s: START_UNIT failed to sdev:"
979                                                        " 0x%p\n", current->comm, sdev));
980                 }
981         }
982
983         return list_empty(work_q);
984 }
985
986
987 /**
988  * scsi_eh_bus_device_reset - send bdr if needed
989  * @shost:      scsi host being recovered.
990  * @eh_done_q:  list_head for processed commands.
991  *
992  * Notes:
993  *    Try a bus device reset.  still, look to see whether we have multiple
994  *    devices that are jammed or not - if we have multiple devices, it
995  *    makes no sense to try bus_device_reset - we really would need to try
996  *    a bus_reset instead. 
997  **/
998 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
999                                     struct list_head *work_q,
1000                                     struct list_head *done_q)
1001 {
1002         struct list_head *lh, *lh_sf;
1003         struct scsi_cmnd *scmd, *bdr_scmd;
1004         struct scsi_device *sdev;
1005         int rtn;
1006
1007         shost_for_each_device(sdev, shost) {
1008                 bdr_scmd = NULL;
1009                 list_for_each_entry(scmd, work_q, eh_entry)
1010                         if (scmd->device == sdev) {
1011                                 bdr_scmd = scmd;
1012                                 break;
1013                         }
1014
1015                 if (!bdr_scmd)
1016                         continue;
1017
1018                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1019                                                   " 0x%p\n", current->comm,
1020                                                   sdev));
1021                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1022                 if (rtn == SUCCESS) {
1023                         if (!scsi_device_online(sdev) ||
1024                             !scsi_eh_tur(bdr_scmd)) {
1025                                 list_for_each_safe(lh, lh_sf,
1026                                                    work_q) {
1027                                         scmd = list_entry(lh, struct
1028                                                           scsi_cmnd,
1029                                                           eh_entry);
1030                                         if (scmd->device == sdev)
1031                                                 scsi_eh_finish_cmd(scmd,
1032                                                                    done_q);
1033                                 }
1034                         }
1035                 } else {
1036                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1037                                                           " failed sdev:"
1038                                                           "0x%p\n",
1039                                                           current->comm,
1040                                                            sdev));
1041                 }
1042         }
1043
1044         return list_empty(work_q);
1045 }
1046
1047 /**
1048  * scsi_try_bus_reset - ask host to perform a bus reset
1049  * @scmd:       SCSI cmd to send bus reset.
1050  **/
1051 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
1052 {
1053         unsigned long flags;
1054         int rtn;
1055
1056         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1057                                           __FUNCTION__));
1058         scmd->owner = SCSI_OWNER_LOWLEVEL;
1059
1060         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1061                 return FAILED;
1062
1063         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1064         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1065         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1066
1067         if (rtn == SUCCESS) {
1068                 if (!scmd->device->host->hostt->skip_settle_delay)
1069                         ssleep(BUS_RESET_SETTLE_TIME);
1070                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1071                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1072                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1073         }
1074
1075         return rtn;
1076 }
1077
1078 /**
1079  * scsi_try_host_reset - ask host adapter to reset itself
1080  * @scmd:       SCSI cmd to send hsot reset.
1081  **/
1082 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1083 {
1084         unsigned long flags;
1085         int rtn;
1086
1087         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1088                                           __FUNCTION__));
1089         scmd->owner = SCSI_OWNER_LOWLEVEL;
1090
1091         if (!scmd->device->host->hostt->eh_host_reset_handler)
1092                 return FAILED;
1093
1094         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1095         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1096         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1097
1098         if (rtn == SUCCESS) {
1099                 if (!scmd->device->host->hostt->skip_settle_delay)
1100                         ssleep(HOST_RESET_SETTLE_TIME);
1101                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1102                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1103                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1104         }
1105
1106         return rtn;
1107 }
1108
1109 /**
1110  * scsi_eh_bus_reset - send a bus reset 
1111  * @shost:      scsi host being recovered.
1112  * @eh_done_q:  list_head for processed commands.
1113  **/
1114 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1115                              struct list_head *work_q,
1116                              struct list_head *done_q)
1117 {
1118         struct list_head *lh, *lh_sf;
1119         struct scsi_cmnd *scmd;
1120         struct scsi_cmnd *chan_scmd;
1121         unsigned int channel;
1122         int rtn;
1123
1124         /*
1125          * we really want to loop over the various channels, and do this on
1126          * a channel by channel basis.  we should also check to see if any
1127          * of the failed commands are on soft_reset devices, and if so, skip
1128          * the reset.  
1129          */
1130
1131         for (channel = 0; channel <= shost->max_channel; channel++) {
1132                 chan_scmd = NULL;
1133                 list_for_each_entry(scmd, work_q, eh_entry) {
1134                         if (channel == scmd->device->channel) {
1135                                 chan_scmd = scmd;
1136                                 break;
1137                                 /*
1138                                  * FIXME add back in some support for
1139                                  * soft_reset devices.
1140                                  */
1141                         }
1142                 }
1143
1144                 if (!chan_scmd)
1145                         continue;
1146                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1147                                                   " %d\n", current->comm,
1148                                                   channel));
1149                 rtn = scsi_try_bus_reset(chan_scmd);
1150                 if (rtn == SUCCESS) {
1151                         list_for_each_safe(lh, lh_sf, work_q) {
1152                                 scmd = list_entry(lh, struct scsi_cmnd,
1153                                                   eh_entry);
1154                                 if (channel == scmd->device->channel)
1155                                         if (!scsi_device_online(scmd->device) ||
1156                                             !scsi_eh_tur(scmd))
1157                                                 scsi_eh_finish_cmd(scmd,
1158                                                                    done_q);
1159                         }
1160                 } else {
1161                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1162                                                           " failed chan: %d\n",
1163                                                           current->comm,
1164                                                           channel));
1165                 }
1166         }
1167         return list_empty(work_q);
1168 }
1169
1170 /**
1171  * scsi_eh_host_reset - send a host reset 
1172  * @work_q:     list_head for processed commands.
1173  * @done_q:     list_head for processed commands.
1174  **/
1175 static int scsi_eh_host_reset(struct list_head *work_q,
1176                               struct list_head *done_q)
1177 {
1178         int rtn;
1179         struct list_head *lh, *lh_sf;
1180         struct scsi_cmnd *scmd;
1181
1182         if (!list_empty(work_q)) {
1183                 scmd = list_entry(work_q->next,
1184                                   struct scsi_cmnd, eh_entry);
1185
1186                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1187                                                   , current->comm));
1188
1189                 rtn = scsi_try_host_reset(scmd);
1190                 if (rtn == SUCCESS) {
1191                         list_for_each_safe(lh, lh_sf, work_q) {
1192                                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1193                                 if (!scsi_device_online(scmd->device) ||
1194                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1195                                     !scsi_eh_tur(scmd))
1196                                         scsi_eh_finish_cmd(scmd, done_q);
1197                         }
1198                 } else {
1199                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1200                                                           " failed\n",
1201                                                           current->comm));
1202                 }
1203         }
1204         return list_empty(work_q);
1205 }
1206
1207 /**
1208  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1209  * @work_q:     list_head for processed commands.
1210  * @done_q:     list_head for processed commands.
1211  *
1212  **/
1213 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1214                                   struct list_head *done_q)
1215 {
1216         struct list_head *lh, *lh_sf;
1217         struct scsi_cmnd *scmd;
1218
1219         list_for_each_safe(lh, lh_sf, work_q) {
1220                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1221                 printk(KERN_INFO "scsi: Device offlined - not"
1222                                 " ready after error recovery: host"
1223                                 " %d channel %d id %d lun %d\n",
1224                                 scmd->device->host->host_no,
1225                                 scmd->device->channel,
1226                                 scmd->device->id,
1227                                 scmd->device->lun);
1228                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1229                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD)) {
1230                         /*
1231                          * FIXME: Handle lost cmds.
1232                          */
1233                 }
1234                 scsi_eh_finish_cmd(scmd, done_q);
1235         }
1236         return;
1237 }
1238
1239 /**
1240  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1241  * @scmd:       SCSI cmd to examine.
1242  *
1243  * Notes:
1244  *    This is *only* called when we are examining the status after sending
1245  *    out the actual data command.  any commands that are queued for error
1246  *    recovery (e.g. test_unit_ready) do *not* come through here.
1247  *
1248  *    When this routine returns failed, it means the error handler thread
1249  *    is woken.  In cases where the error code indicates an error that
1250  *    doesn't require the error handler read (i.e. we don't need to
1251  *    abort/reset), this function should return SUCCESS.
1252  **/
1253 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1254 {
1255         int rtn;
1256
1257         /*
1258          * if the device is offline, then we clearly just pass the result back
1259          * up to the top level.
1260          */
1261         if (!scsi_device_online(scmd->device)) {
1262                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1263                                                   " as SUCCESS\n",
1264                                                   __FUNCTION__));
1265                 return SUCCESS;
1266         }
1267
1268         /*
1269          * first check the host byte, to see if there is anything in there
1270          * that would indicate what we need to do.
1271          */
1272         switch (host_byte(scmd->result)) {
1273         case DID_PASSTHROUGH:
1274                 /*
1275                  * no matter what, pass this through to the upper layer.
1276                  * nuke this special code so that it looks like we are saying
1277                  * did_ok.
1278                  */
1279                 scmd->result &= 0xff00ffff;
1280                 return SUCCESS;
1281         case DID_OK:
1282                 /*
1283                  * looks good.  drop through, and check the next byte.
1284                  */
1285                 break;
1286         case DID_NO_CONNECT:
1287         case DID_BAD_TARGET:
1288         case DID_ABORT:
1289                 /*
1290                  * note - this means that we just report the status back
1291                  * to the top level driver, not that we actually think
1292                  * that it indicates SUCCESS.
1293                  */
1294                 return SUCCESS;
1295                 /*
1296                  * when the low level driver returns did_soft_error,
1297                  * it is responsible for keeping an internal retry counter 
1298                  * in order to avoid endless loops (db)
1299                  *
1300                  * actually this is a bug in this function here.  we should
1301                  * be mindful of the maximum number of retries specified
1302                  * and not get stuck in a loop.
1303                  */
1304         case DID_SOFT_ERROR:
1305                 goto maybe_retry;
1306         case DID_IMM_RETRY:
1307                 return NEEDS_RETRY;
1308
1309         case DID_ERROR:
1310                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1311                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1312                         /*
1313                          * execute reservation conflict processing code
1314                          * lower down
1315                          */
1316                         break;
1317                 /* fallthrough */
1318
1319         case DID_BUS_BUSY:
1320         case DID_PARITY:
1321                 goto maybe_retry;
1322         case DID_TIME_OUT:
1323                 /*
1324                  * when we scan the bus, we get timeout messages for
1325                  * these commands if there is no device available.
1326                  * other hosts report did_no_connect for the same thing.
1327                  */
1328                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1329                      scmd->cmnd[0] == INQUIRY)) {
1330                         return SUCCESS;
1331                 } else {
1332                         return FAILED;
1333                 }
1334         case DID_RESET:
1335                 return SUCCESS;
1336         default:
1337                 return FAILED;
1338         }
1339
1340         /*
1341          * next, check the message byte.
1342          */
1343         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1344                 return FAILED;
1345
1346         /*
1347          * check the status byte to see if this indicates anything special.
1348          */
1349         switch (status_byte(scmd->result)) {
1350         case QUEUE_FULL:
1351                 /*
1352                  * the case of trying to send too many commands to a
1353                  * tagged queueing device.
1354                  */
1355         case BUSY:
1356                 /*
1357                  * device can't talk to us at the moment.  Should only
1358                  * occur (SAM-3) when the task queue is empty, so will cause
1359                  * the empty queue handling to trigger a stall in the
1360                  * device.
1361                  */
1362                 return ADD_TO_MLQUEUE;
1363         case GOOD:
1364         case COMMAND_TERMINATED:
1365         case TASK_ABORTED:
1366                 return SUCCESS;
1367         case CHECK_CONDITION:
1368                 rtn = scsi_check_sense(scmd);
1369                 if (rtn == NEEDS_RETRY)
1370                         goto maybe_retry;
1371                 /* if rtn == FAILED, we have no sense information;
1372                  * returning FAILED will wake the error handler thread
1373                  * to collect the sense and redo the decide
1374                  * disposition */
1375                 return rtn;
1376         case CONDITION_GOOD:
1377         case INTERMEDIATE_GOOD:
1378         case INTERMEDIATE_C_GOOD:
1379         case ACA_ACTIVE:
1380                 /*
1381                  * who knows?  FIXME(eric)
1382                  */
1383                 return SUCCESS;
1384
1385         case RESERVATION_CONFLICT:
1386                 printk(KERN_INFO "scsi: reservation conflict: host"
1387                                 " %d channel %d id %d lun %d\n",
1388                        scmd->device->host->host_no, scmd->device->channel,
1389                        scmd->device->id, scmd->device->lun);
1390                 return SUCCESS; /* causes immediate i/o error */
1391         default:
1392                 return FAILED;
1393         }
1394         return FAILED;
1395
1396       maybe_retry:
1397
1398         /* we requeue for retry because the error was retryable, and
1399          * the request was not marked fast fail.  Note that above,
1400          * even if the request is marked fast fail, we still requeue
1401          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1402         if ((++scmd->retries) < scmd->allowed 
1403             && !blk_noretry_request(scmd->request)) {
1404                 return NEEDS_RETRY;
1405         } else {
1406                 /*
1407                  * no more retries - report this one back to upper level.
1408                  */
1409                 return SUCCESS;
1410         }
1411 }
1412
1413 /**
1414  * scsi_eh_lock_done - done function for eh door lock request
1415  * @scmd:       SCSI command block for the door lock request
1416  *
1417  * Notes:
1418  *      We completed the asynchronous door lock request, and it has either
1419  *      locked the door or failed.  We must free the command structures
1420  *      associated with this request.
1421  **/
1422 static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
1423 {
1424         struct scsi_request *sreq = scmd->sc_request;
1425
1426         scsi_release_request(sreq);
1427 }
1428
1429
1430 /**
1431  * scsi_eh_lock_door - Prevent medium removal for the specified device
1432  * @sdev:       SCSI device to prevent medium removal
1433  *
1434  * Locking:
1435  *      We must be called from process context; scsi_allocate_request()
1436  *      may sleep.
1437  *
1438  * Notes:
1439  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1440  *      head of the devices request queue, and continue.
1441  *
1442  * Bugs:
1443  *      scsi_allocate_request() may sleep waiting for existing requests to
1444  *      be processed.  However, since we haven't kicked off any request
1445  *      processing for this host, this may deadlock.
1446  *
1447  *      If scsi_allocate_request() fails for what ever reason, we
1448  *      completely forget to lock the door.
1449  **/
1450 static void scsi_eh_lock_door(struct scsi_device *sdev)
1451 {
1452         struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
1453
1454         if (unlikely(!sreq)) {
1455                 printk(KERN_ERR "%s: request allocate failed,"
1456                        "prevent media removal cmd not sent\n", __FUNCTION__);
1457                 return;
1458         }
1459
1460         sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1461         sreq->sr_cmnd[1] = 0;
1462         sreq->sr_cmnd[2] = 0;
1463         sreq->sr_cmnd[3] = 0;
1464         sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
1465         sreq->sr_cmnd[5] = 0;
1466         sreq->sr_data_direction = DMA_NONE;
1467         sreq->sr_bufflen = 0;
1468         sreq->sr_buffer = NULL;
1469         sreq->sr_allowed = 5;
1470         sreq->sr_done = scsi_eh_lock_done;
1471         sreq->sr_timeout_per_command = 10 * HZ;
1472         sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
1473
1474         scsi_insert_special_req(sreq, 1);
1475 }
1476
1477
1478 /**
1479  * scsi_restart_operations - restart io operations to the specified host.
1480  * @shost:      Host we are restarting.
1481  *
1482  * Notes:
1483  *    When we entered the error handler, we blocked all further i/o to
1484  *    this device.  we need to 'reverse' this process.
1485  **/
1486 static void scsi_restart_operations(struct Scsi_Host *shost)
1487 {
1488         struct scsi_device *sdev;
1489
1490         /*
1491          * If the door was locked, we need to insert a door lock request
1492          * onto the head of the SCSI request queue for the device.  There
1493          * is no point trying to lock the door of an off-line device.
1494          */
1495         shost_for_each_device(sdev, shost) {
1496                 if (scsi_device_online(sdev) && sdev->locked)
1497                         scsi_eh_lock_door(sdev);
1498         }
1499
1500         /*
1501          * next free up anything directly waiting upon the host.  this
1502          * will be requests for character device operations, and also for
1503          * ioctls to queued block devices.
1504          */
1505         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1506                                           __FUNCTION__));
1507
1508         clear_bit(SHOST_RECOVERY, &shost->shost_state);
1509
1510         wake_up(&shost->host_wait);
1511
1512         /*
1513          * finally we need to re-initiate requests that may be pending.  we will
1514          * have had everything blocked while error handling is taking place, and
1515          * now that error recovery is done, we will need to ensure that these
1516          * requests are started.
1517          */
1518         scsi_run_host_queues(shost);
1519 }
1520
1521 /**
1522  * scsi_eh_ready_devs - check device ready state and recover if not.
1523  * @shost:      host to be recovered.
1524  * @eh_done_q:  list_head for processed commands.
1525  *
1526  **/
1527 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1528                                struct list_head *work_q,
1529                                struct list_head *done_q)
1530 {
1531         if (!scsi_eh_stu(shost, work_q, done_q))
1532                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1533                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1534                                 if (!scsi_eh_host_reset(work_q, done_q))
1535                                         scsi_eh_offline_sdevs(work_q, done_q);
1536 }
1537
1538 /**
1539  * scsi_eh_flush_done_q - finish processed commands or retry them.
1540  * @done_q:     list_head of processed commands.
1541  *
1542  **/
1543 static void scsi_eh_flush_done_q(struct list_head *done_q)
1544 {
1545         struct list_head *lh, *lh_sf;
1546         struct scsi_cmnd *scmd;
1547
1548         list_for_each_safe(lh, lh_sf, done_q) {
1549                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1550                 list_del_init(lh);
1551                 if (scsi_device_online(scmd->device) &&
1552                     !blk_noretry_request(scmd->request) &&
1553                     (++scmd->retries < scmd->allowed)) {
1554                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1555                                                           " retry cmd: %p\n",
1556                                                           current->comm,
1557                                                           scmd));
1558                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1559                 } else {
1560                         if (!scmd->result)
1561                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1562                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1563                                                         " cmd: %p\n",
1564                                                         current->comm, scmd));
1565                         scsi_finish_command(scmd);
1566                 }
1567         }
1568 }
1569
1570 /**
1571  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1572  * @shost:      Host to unjam.
1573  *
1574  * Notes:
1575  *    When we come in here, we *know* that all commands on the bus have
1576  *    either completed, failed or timed out.  we also know that no further
1577  *    commands are being sent to the host, so things are relatively quiet
1578  *    and we have freedom to fiddle with things as we wish.
1579  *
1580  *    This is only the *default* implementation.  it is possible for
1581  *    individual drivers to supply their own version of this function, and
1582  *    if the maintainer wishes to do this, it is strongly suggested that
1583  *    this function be taken as a template and modified.  this function
1584  *    was designed to correctly handle problems for about 95% of the
1585  *    different cases out there, and it should always provide at least a
1586  *    reasonable amount of error recovery.
1587  *
1588  *    Any command marked 'failed' or 'timeout' must eventually have
1589  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1590  *    here, so when we restart the host after we return it should have an
1591  *    empty queue.
1592  **/
1593 static void scsi_unjam_host(struct Scsi_Host *shost)
1594 {
1595         unsigned long flags;
1596         LIST_HEAD(eh_work_q);
1597         LIST_HEAD(eh_done_q);
1598
1599         spin_lock_irqsave(shost->host_lock, flags);
1600         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1601         spin_unlock_irqrestore(shost->host_lock, flags);
1602
1603         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1604
1605         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1606                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1607                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1608
1609         scsi_eh_flush_done_q(&eh_done_q);
1610 }
1611
1612 /**
1613  * scsi_error_handler - Handle errors/timeouts of SCSI cmds.
1614  * @data:       Host for which we are running.
1615  *
1616  * Notes:
1617  *    This is always run in the context of a kernel thread.  The idea is
1618  *    that we start this thing up when the kernel starts up (one per host
1619  *    that we detect), and it immediately goes to sleep and waits for some
1620  *    event (i.e. failure).  When this takes place, we have the job of
1621  *    trying to unjam the bus and restarting things.
1622  **/
1623 int scsi_error_handler(void *data)
1624 {
1625         struct Scsi_Host *shost = (struct Scsi_Host *) data;
1626         int rtn;
1627         DECLARE_MUTEX_LOCKED(sem);
1628
1629         /*
1630          *    Flush resources
1631          */
1632
1633         daemonize("scsi_eh_%d", shost->host_no);
1634
1635         current->flags |= PF_NOFREEZE;
1636
1637         shost->eh_wait = &sem;
1638         shost->ehandler = current;
1639
1640         /*
1641          * Wake up the thread that created us.
1642          */
1643         SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
1644                                           " scsi_eh_%d\n",shost->host_no));
1645
1646         complete(shost->eh_notify);
1647
1648         while (1) {
1649                 /*
1650                  * If we get a signal, it means we are supposed to go
1651                  * away and die.  This typically happens if the user is
1652                  * trying to unload a module.
1653                  */
1654                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1655                                                   " scsi_eh_%d"
1656                                                   " sleeping\n",shost->host_no));
1657
1658                 /*
1659                  * Note - we always use down_interruptible with the semaphore
1660                  * even if the module was loaded as part of the kernel.  The
1661                  * reason is that down() will cause this thread to be counted
1662                  * in the load average as a running process, and down
1663                  * interruptible doesn't.  Given that we need to allow this
1664                  * thread to die if the driver was loaded as a module, using
1665                  * semaphores isn't unreasonable.
1666                  */
1667                 down_interruptible(&sem);
1668                 if (shost->eh_kill)
1669                         break;
1670
1671                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1672                                                   " scsi_eh_%d waking"
1673                                                   " up\n",shost->host_no));
1674
1675                 shost->eh_active = 1;
1676
1677                 /*
1678                  * We have a host that is failing for some reason.  Figure out
1679                  * what we need to do to get it up and online again (if we can).
1680                  * If we fail, we end up taking the thing offline.
1681                  */
1682                 if (shost->hostt->eh_strategy_handler) 
1683                         rtn = shost->hostt->eh_strategy_handler(shost);
1684                 else
1685                         scsi_unjam_host(shost);
1686
1687                 shost->eh_active = 0;
1688
1689                 /*
1690                  * Note - if the above fails completely, the action is to take
1691                  * individual devices offline and flush the queue of any
1692                  * outstanding requests that may have been pending.  When we
1693                  * restart, we restart any I/O to any other devices on the bus
1694                  * which are still online.
1695                  */
1696                 scsi_restart_operations(shost);
1697
1698         }
1699
1700         SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
1701                                           " exiting\n",shost->host_no));
1702
1703         /*
1704          * Make sure that nobody tries to wake us up again.
1705          */
1706         shost->eh_wait = NULL;
1707
1708         /*
1709          * Knock this down too.  From this point on, the host is flying
1710          * without a pilot.  If this is because the module is being unloaded,
1711          * that's fine.  If the user sent a signal to this thing, we are
1712          * potentially in real danger.
1713          */
1714         shost->eh_active = 0;
1715         shost->ehandler = NULL;
1716
1717         /*
1718          * If anyone is waiting for us to exit (i.e. someone trying to unload
1719          * a driver), then wake up that process to let them know we are on
1720          * the way out the door.
1721          */
1722         complete_and_exit(shost->eh_notify, 0);
1723         return 0;
1724 }
1725
1726 /*
1727  * Function:    scsi_report_bus_reset()
1728  *
1729  * Purpose:     Utility function used by low-level drivers to report that
1730  *              they have observed a bus reset on the bus being handled.
1731  *
1732  * Arguments:   shost       - Host in question
1733  *              channel     - channel on which reset was observed.
1734  *
1735  * Returns:     Nothing
1736  *
1737  * Lock status: Host lock must be held.
1738  *
1739  * Notes:       This only needs to be called if the reset is one which
1740  *              originates from an unknown location.  Resets originated
1741  *              by the mid-level itself don't need to call this, but there
1742  *              should be no harm.
1743  *
1744  *              The main purpose of this is to make sure that a CHECK_CONDITION
1745  *              is properly treated.
1746  */
1747 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1748 {
1749         struct scsi_device *sdev;
1750
1751         __shost_for_each_device(sdev, shost) {
1752                 if (channel == sdev->channel) {
1753                         sdev->was_reset = 1;
1754                         sdev->expecting_cc_ua = 1;
1755                 }
1756         }
1757 }
1758 EXPORT_SYMBOL(scsi_report_bus_reset);
1759
1760 /*
1761  * Function:    scsi_report_device_reset()
1762  *
1763  * Purpose:     Utility function used by low-level drivers to report that
1764  *              they have observed a device reset on the device being handled.
1765  *
1766  * Arguments:   shost       - Host in question
1767  *              channel     - channel on which reset was observed
1768  *              target      - target on which reset was observed
1769  *
1770  * Returns:     Nothing
1771  *
1772  * Lock status: Host lock must be held
1773  *
1774  * Notes:       This only needs to be called if the reset is one which
1775  *              originates from an unknown location.  Resets originated
1776  *              by the mid-level itself don't need to call this, but there
1777  *              should be no harm.
1778  *
1779  *              The main purpose of this is to make sure that a CHECK_CONDITION
1780  *              is properly treated.
1781  */
1782 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1783 {
1784         struct scsi_device *sdev;
1785
1786         __shost_for_each_device(sdev, shost) {
1787                 if (channel == sdev->channel &&
1788                     target == sdev->id) {
1789                         sdev->was_reset = 1;
1790                         sdev->expecting_cc_ua = 1;
1791                 }
1792         }
1793 }
1794 EXPORT_SYMBOL(scsi_report_device_reset);
1795
1796 static void
1797 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1798 {
1799 }
1800
1801 /*
1802  * Function:    scsi_reset_provider
1803  *
1804  * Purpose:     Send requested reset to a bus or device at any phase.
1805  *
1806  * Arguments:   device  - device to send reset to
1807  *              flag - reset type (see scsi.h)
1808  *
1809  * Returns:     SUCCESS/FAILURE.
1810  *
1811  * Notes:       This is used by the SCSI Generic driver to provide
1812  *              Bus/Device reset capability.
1813  */
1814 int
1815 scsi_reset_provider(struct scsi_device *dev, int flag)
1816 {
1817         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1818         struct request req;
1819         int rtn;
1820
1821         scmd->request = &req;
1822         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1823         scmd->request->rq_status        = RQ_SCSI_BUSY;
1824         scmd->state                     = SCSI_STATE_INITIALIZING;
1825         scmd->owner                     = SCSI_OWNER_MIDLEVEL;
1826     
1827         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1828     
1829         scmd->scsi_done         = scsi_reset_provider_done_command;
1830         scmd->done                      = NULL;
1831         scmd->buffer                    = NULL;
1832         scmd->bufflen                   = 0;
1833         scmd->request_buffer            = NULL;
1834         scmd->request_bufflen           = 0;
1835         scmd->abort_reason              = DID_ABORT;
1836
1837         scmd->cmd_len                   = 0;
1838
1839         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1840         scmd->sc_request                = NULL;
1841         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1842
1843         init_timer(&scmd->eh_timeout);
1844
1845         /*
1846          * Sometimes the command can get back into the timer chain,
1847          * so use the pid as an identifier.
1848          */
1849         scmd->pid                       = 0;
1850
1851         switch (flag) {
1852         case SCSI_TRY_RESET_DEVICE:
1853                 rtn = scsi_try_bus_device_reset(scmd);
1854                 if (rtn == SUCCESS)
1855                         break;
1856                 /* FALLTHROUGH */
1857         case SCSI_TRY_RESET_BUS:
1858                 rtn = scsi_try_bus_reset(scmd);
1859                 if (rtn == SUCCESS)
1860                         break;
1861                 /* FALLTHROUGH */
1862         case SCSI_TRY_RESET_HOST:
1863                 rtn = scsi_try_host_reset(scmd);
1864                 break;
1865         default:
1866                 rtn = FAILED;
1867         }
1868
1869         scsi_delete_timer(scmd);
1870         scsi_next_command(scmd);
1871         return rtn;
1872 }
1873 EXPORT_SYMBOL(scsi_reset_provider);
1874
1875 /**
1876  * scsi_normalize_sense - normalize main elements from either fixed or
1877  *                      descriptor sense data format into a common format.
1878  *
1879  * @sense_buffer:       byte array containing sense data returned by device
1880  * @sb_len:             number of valid bytes in sense_buffer
1881  * @sshdr:              pointer to instance of structure that common
1882  *                      elements are written to.
1883  *
1884  * Notes:
1885  *      The "main elements" from sense data are: response_code, sense_key,
1886  *      asc, ascq and additional_length (only for descriptor format).
1887  *
1888  *      Typically this function can be called after a device has
1889  *      responded to a SCSI command with the CHECK_CONDITION status.
1890  *
1891  * Return value:
1892  *      1 if valid sense data information found, else 0;
1893  **/
1894 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1895                          struct scsi_sense_hdr *sshdr)
1896 {
1897         if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
1898                 return 0;
1899
1900         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1901
1902         sshdr->response_code = (sense_buffer[0] & 0x7f);
1903         if (sshdr->response_code >= 0x72) {
1904                 /*
1905                  * descriptor format
1906                  */
1907                 if (sb_len > 1)
1908                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1909                 if (sb_len > 2)
1910                         sshdr->asc = sense_buffer[2];
1911                 if (sb_len > 3)
1912                         sshdr->ascq = sense_buffer[3];
1913                 if (sb_len > 7)
1914                         sshdr->additional_length = sense_buffer[7];
1915         } else {
1916                 /* 
1917                  * fixed format
1918                  */
1919                 if (sb_len > 2)
1920                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1921                 if (sb_len > 7) {
1922                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1923                                          sb_len : (sense_buffer[7] + 8);
1924                         if (sb_len > 12)
1925                                 sshdr->asc = sense_buffer[12];
1926                         if (sb_len > 13)
1927                                 sshdr->ascq = sense_buffer[13];
1928                 }
1929         }
1930
1931         return 1;
1932 }
1933 EXPORT_SYMBOL(scsi_normalize_sense);
1934
1935 int scsi_request_normalize_sense(struct scsi_request *sreq,
1936                                  struct scsi_sense_hdr *sshdr)
1937 {
1938         return scsi_normalize_sense(sreq->sr_sense_buffer,
1939                         sizeof(sreq->sr_sense_buffer), sshdr);
1940 }
1941 EXPORT_SYMBOL(scsi_request_normalize_sense);
1942
1943 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1944                                  struct scsi_sense_hdr *sshdr)
1945 {
1946         return scsi_normalize_sense(cmd->sense_buffer,
1947                         sizeof(cmd->sense_buffer), sshdr);
1948 }
1949 EXPORT_SYMBOL(scsi_command_normalize_sense);
1950
1951 /**
1952  * scsi_sense_desc_find - search for a given descriptor type in
1953  *                      descriptor sense data format.
1954  *
1955  * @sense_buffer:       byte array of descriptor format sense data
1956  * @sb_len:             number of valid bytes in sense_buffer
1957  * @desc_type:          value of descriptor type to find
1958  *                      (e.g. 0 -> information)
1959  *
1960  * Notes:
1961  *      only valid when sense data is in descriptor format
1962  *
1963  * Return value:
1964  *      pointer to start of (first) descriptor if found else NULL
1965  **/
1966 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1967                                 int desc_type)
1968 {
1969         int add_sen_len, add_len, desc_len, k;
1970         const u8 * descp;
1971
1972         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1973                 return NULL;
1974         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1975                 return NULL;
1976         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1977                         add_sen_len : (sb_len - 8);
1978         descp = &sense_buffer[8];
1979         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1980                 descp += desc_len;
1981                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1982                 desc_len = add_len + 2;
1983                 if (descp[0] == desc_type)
1984                         return descp;
1985                 if (add_len < 0) // short descriptor ??
1986                         break;
1987         }
1988         return NULL;
1989 }
1990 EXPORT_SYMBOL(scsi_sense_desc_find);
1991
1992 /**
1993  * scsi_get_sense_info_fld - attempts to get information field from
1994  *                      sense data (either fixed or descriptor format)
1995  *
1996  * @sense_buffer:       byte array of sense data
1997  * @sb_len:             number of valid bytes in sense_buffer
1998  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1999  *                      field will be placed if found.
2000  *
2001  * Return value:
2002  *      1 if information field found, 0 if not found.
2003  **/
2004 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2005                             u64 * info_out)
2006 {
2007         int j;
2008         const u8 * ucp;
2009         u64 ull;
2010
2011         if (sb_len < 7)
2012                 return 0;
2013         switch (sense_buffer[0] & 0x7f) {
2014         case 0x70:
2015         case 0x71:
2016                 if (sense_buffer[0] & 0x80) {
2017                         *info_out = (sense_buffer[3] << 24) +
2018                                     (sense_buffer[4] << 16) +
2019                                     (sense_buffer[5] << 8) + sense_buffer[6];
2020                         return 1;
2021                 } else
2022                         return 0;
2023         case 0x72:
2024         case 0x73:
2025                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2026                                            0 /* info desc */);
2027                 if (ucp && (0xa == ucp[1])) {
2028                         ull = 0;
2029                         for (j = 0; j < 8; ++j) {
2030                                 if (j > 0)
2031                                         ull <<= 8;
2032                                 ull |= ucp[4 + j];
2033                         }
2034                         *info_out = ull;
2035                         return 1;
2036                 } else
2037                         return 0;
2038         default:
2039                 return 0;
2040         }
2041 }
2042 EXPORT_SYMBOL(scsi_get_sense_info_fld);