[SCSI] scsi_dh: add infrastructure for SCSI Device Handlers
[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/kernel.h>
22 #include <linux/freezer.h>
23 #include <linux/kthread.h>
24 #include <linux/interrupt.h>
25 #include <linux/blkdev.h>
26 #include <linux/delay.h>
27
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_eh.h>
33 #include <scsi/scsi_transport.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_ioctl.h>
36
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
39 #include "scsi_transport_api.h"
40
41 #define SENSE_TIMEOUT           (10*HZ)
42
43 /*
44  * These should *probably* be handled by the host itself.
45  * Since it is allowed to sleep, it probably should.
46  */
47 #define BUS_RESET_SETTLE_TIME   (10)
48 #define HOST_RESET_SETTLE_TIME  (10)
49
50 /* called with shost->host_lock held */
51 void scsi_eh_wakeup(struct Scsi_Host *shost)
52 {
53         if (shost->host_busy == shost->host_failed) {
54                 wake_up_process(shost->ehandler);
55                 SCSI_LOG_ERROR_RECOVERY(5,
56                                 printk("Waking error handler thread\n"));
57         }
58 }
59
60 /**
61  * scsi_schedule_eh - schedule EH for SCSI host
62  * @shost:      SCSI host to invoke error handling on.
63  *
64  * Schedule SCSI EH without scmd.
65  */
66 void scsi_schedule_eh(struct Scsi_Host *shost)
67 {
68         unsigned long flags;
69
70         spin_lock_irqsave(shost->host_lock, flags);
71
72         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
73             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
74                 shost->host_eh_scheduled++;
75                 scsi_eh_wakeup(shost);
76         }
77
78         spin_unlock_irqrestore(shost->host_lock, flags);
79 }
80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
81
82 /**
83  * scsi_eh_scmd_add - add scsi cmd to error handling.
84  * @scmd:       scmd to run eh on.
85  * @eh_flag:    optional SCSI_EH flag.
86  *
87  * Return value:
88  *      0 on failure.
89  */
90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
91 {
92         struct Scsi_Host *shost = scmd->device->host;
93         unsigned long flags;
94         int ret = 0;
95
96         if (!shost->ehandler)
97                 return 0;
98
99         spin_lock_irqsave(shost->host_lock, flags);
100         if (scsi_host_set_state(shost, SHOST_RECOVERY))
101                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
102                         goto out_unlock;
103
104         ret = 1;
105         scmd->eh_eflags |= eh_flag;
106         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
107         shost->host_failed++;
108         scsi_eh_wakeup(shost);
109  out_unlock:
110         spin_unlock_irqrestore(shost->host_lock, flags);
111         return ret;
112 }
113
114 /**
115  * scsi_add_timer - Start timeout timer for a single scsi command.
116  * @scmd:       scsi command that is about to start running.
117  * @timeout:    amount of time to allow this command to run.
118  * @complete:   timeout function to call if timer isn't canceled.
119  *
120  * Notes:
121  *    This should be turned into an inline function.  Each scsi command
122  *    has its own timer, and as it is added to the queue, we set up the
123  *    timer.  When the command completes, we cancel the timer.
124  */
125 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
126                     void (*complete)(struct scsi_cmnd *))
127 {
128
129         /*
130          * If the clock was already running for this command, then
131          * first delete the timer.  The timer handling code gets rather
132          * confused if we don't do this.
133          */
134         if (scmd->eh_timeout.function)
135                 del_timer(&scmd->eh_timeout);
136
137         scmd->eh_timeout.data = (unsigned long)scmd;
138         scmd->eh_timeout.expires = jiffies + timeout;
139         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
140
141         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
142                                           " %d, (%p)\n", __FUNCTION__,
143                                           scmd, timeout, complete));
144
145         add_timer(&scmd->eh_timeout);
146 }
147
148 /**
149  * scsi_delete_timer - Delete/cancel timer for a given function.
150  * @scmd:       Cmd that we are canceling timer for
151  *
152  * Notes:
153  *     This should be turned into an inline function.
154  *
155  * Return value:
156  *     1 if we were able to detach the timer.  0 if we blew it, and the
157  *     timer function has already started to run.
158  */
159 int scsi_delete_timer(struct scsi_cmnd *scmd)
160 {
161         int rtn;
162
163         rtn = del_timer(&scmd->eh_timeout);
164
165         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
166                                          " rtn: %d\n", __FUNCTION__,
167                                          scmd, rtn));
168
169         scmd->eh_timeout.data = (unsigned long)NULL;
170         scmd->eh_timeout.function = NULL;
171
172         return rtn;
173 }
174
175 /**
176  * scsi_times_out - Timeout function for normal scsi commands.
177  * @scmd:       Cmd that is timing out.
178  *
179  * Notes:
180  *     We do not need to lock this.  There is the potential for a race
181  *     only in that the normal completion handling might run, but if the
182  *     normal completion function determines that the timer has already
183  *     fired, then it mustn't do anything.
184  */
185 void scsi_times_out(struct scsi_cmnd *scmd)
186 {
187         enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
188
189         scsi_log_completion(scmd, TIMEOUT_ERROR);
190
191         if (scmd->device->host->transportt->eh_timed_out)
192                 eh_timed_out = scmd->device->host->transportt->eh_timed_out;
193         else if (scmd->device->host->hostt->eh_timed_out)
194                 eh_timed_out = scmd->device->host->hostt->eh_timed_out;
195         else
196                 eh_timed_out = NULL;
197
198         if (eh_timed_out)
199                 switch (eh_timed_out(scmd)) {
200                 case EH_HANDLED:
201                         __scsi_done(scmd);
202                         return;
203                 case EH_RESET_TIMER:
204                         scsi_add_timer(scmd, scmd->timeout_per_command,
205                                        scsi_times_out);
206                         return;
207                 case EH_NOT_HANDLED:
208                         break;
209                 }
210
211         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
212                 scmd->result |= DID_TIME_OUT << 16;
213                 __scsi_done(scmd);
214         }
215 }
216
217 /**
218  * scsi_block_when_processing_errors - Prevent cmds from being queued.
219  * @sdev:       Device on which we are performing recovery.
220  *
221  * Description:
222  *     We block until the host is out of error recovery, and then check to
223  *     see whether the host or the device is offline.
224  *
225  * Return value:
226  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
227  */
228 int scsi_block_when_processing_errors(struct scsi_device *sdev)
229 {
230         int online;
231
232         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
233
234         online = scsi_device_online(sdev);
235
236         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
237                                           online));
238
239         return online;
240 }
241 EXPORT_SYMBOL(scsi_block_when_processing_errors);
242
243 #ifdef CONFIG_SCSI_LOGGING
244 /**
245  * scsi_eh_prt_fail_stats - Log info on failures.
246  * @shost:      scsi host being recovered.
247  * @work_q:     Queue of scsi cmds to process.
248  */
249 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
250                                           struct list_head *work_q)
251 {
252         struct scsi_cmnd *scmd;
253         struct scsi_device *sdev;
254         int total_failures = 0;
255         int cmd_failed = 0;
256         int cmd_cancel = 0;
257         int devices_failed = 0;
258
259         shost_for_each_device(sdev, shost) {
260                 list_for_each_entry(scmd, work_q, eh_entry) {
261                         if (scmd->device == sdev) {
262                                 ++total_failures;
263                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
264                                         ++cmd_cancel;
265                                 else 
266                                         ++cmd_failed;
267                         }
268                 }
269
270                 if (cmd_cancel || cmd_failed) {
271                         SCSI_LOG_ERROR_RECOVERY(3,
272                                 sdev_printk(KERN_INFO, sdev,
273                                             "%s: cmds failed: %d, cancel: %d\n",
274                                             __FUNCTION__, cmd_failed,
275                                             cmd_cancel));
276                         cmd_cancel = 0;
277                         cmd_failed = 0;
278                         ++devices_failed;
279                 }
280         }
281
282         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
283                                           " devices require eh work\n",
284                                   total_failures, devices_failed));
285 }
286 #endif
287
288 /**
289  * scsi_check_sense - Examine scsi cmd sense
290  * @scmd:       Cmd to have sense checked.
291  *
292  * Return value:
293  *      SUCCESS or FAILED or NEEDS_RETRY
294  *
295  * Notes:
296  *      When a deferred error is detected the current command has
297  *      not been executed and needs retrying.
298  */
299 static int scsi_check_sense(struct scsi_cmnd *scmd)
300 {
301         struct scsi_device *sdev = scmd->device;
302         struct scsi_sense_hdr sshdr;
303
304         if (! scsi_command_normalize_sense(scmd, &sshdr))
305                 return FAILED;  /* no valid sense data */
306
307         if (scsi_sense_is_deferred(&sshdr))
308                 return NEEDS_RETRY;
309
310         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
311                         sdev->scsi_dh_data->scsi_dh->check_sense) {
312                 int rc;
313
314                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
315                 if (rc != SCSI_RETURN_NOT_HANDLED)
316                         return rc;
317                 /* handler does not care. Drop down to default handling */
318         }
319
320         /*
321          * Previous logic looked for FILEMARK, EOM or ILI which are
322          * mainly associated with tapes and returned SUCCESS.
323          */
324         if (sshdr.response_code == 0x70) {
325                 /* fixed format */
326                 if (scmd->sense_buffer[2] & 0xe0)
327                         return SUCCESS;
328         } else {
329                 /*
330                  * descriptor format: look for "stream commands sense data
331                  * descriptor" (see SSC-3). Assume single sense data
332                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
333                  */
334                 if ((sshdr.additional_length > 3) &&
335                     (scmd->sense_buffer[8] == 0x4) &&
336                     (scmd->sense_buffer[11] & 0xe0))
337                         return SUCCESS;
338         }
339
340         switch (sshdr.sense_key) {
341         case NO_SENSE:
342                 return SUCCESS;
343         case RECOVERED_ERROR:
344                 return /* soft_error */ SUCCESS;
345
346         case ABORTED_COMMAND:
347                 return NEEDS_RETRY;
348         case NOT_READY:
349         case UNIT_ATTENTION:
350                 /*
351                  * if we are expecting a cc/ua because of a bus reset that we
352                  * performed, treat this just as a retry.  otherwise this is
353                  * information that we should pass up to the upper-level driver
354                  * so that we can deal with it there.
355                  */
356                 if (scmd->device->expecting_cc_ua) {
357                         scmd->device->expecting_cc_ua = 0;
358                         return NEEDS_RETRY;
359                 }
360                 /*
361                  * if the device is in the process of becoming ready, we 
362                  * should retry.
363                  */
364                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
365                         return NEEDS_RETRY;
366                 /*
367                  * if the device is not started, we need to wake
368                  * the error handler to start the motor
369                  */
370                 if (scmd->device->allow_restart &&
371                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
372                         return FAILED;
373                 return SUCCESS;
374
375                 /* these three are not supported */
376         case COPY_ABORTED:
377         case VOLUME_OVERFLOW:
378         case MISCOMPARE:
379                 return SUCCESS;
380
381         case MEDIUM_ERROR:
382                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
383                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
384                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
385                         return SUCCESS;
386                 }
387                 return NEEDS_RETRY;
388
389         case HARDWARE_ERROR:
390                 if (scmd->device->retry_hwerror)
391                         return NEEDS_RETRY;
392                 else
393                         return SUCCESS;
394
395         case ILLEGAL_REQUEST:
396         case BLANK_CHECK:
397         case DATA_PROTECT:
398         default:
399                 return SUCCESS;
400         }
401 }
402
403 /**
404  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
405  * @scmd:       SCSI cmd to examine.
406  *
407  * Notes:
408  *    This is *only* called when we are examining the status of commands
409  *    queued during error recovery.  the main difference here is that we
410  *    don't allow for the possibility of retries here, and we are a lot
411  *    more restrictive about what we consider acceptable.
412  */
413 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
414 {
415         /*
416          * first check the host byte, to see if there is anything in there
417          * that would indicate what we need to do.
418          */
419         if (host_byte(scmd->result) == DID_RESET) {
420                 /*
421                  * rats.  we are already in the error handler, so we now
422                  * get to try and figure out what to do next.  if the sense
423                  * is valid, we have a pretty good idea of what to do.
424                  * if not, we mark it as FAILED.
425                  */
426                 return scsi_check_sense(scmd);
427         }
428         if (host_byte(scmd->result) != DID_OK)
429                 return FAILED;
430
431         /*
432          * next, check the message byte.
433          */
434         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
435                 return FAILED;
436
437         /*
438          * now, check the status byte to see if this indicates
439          * anything special.
440          */
441         switch (status_byte(scmd->result)) {
442         case GOOD:
443         case COMMAND_TERMINATED:
444                 return SUCCESS;
445         case CHECK_CONDITION:
446                 return scsi_check_sense(scmd);
447         case CONDITION_GOOD:
448         case INTERMEDIATE_GOOD:
449         case INTERMEDIATE_C_GOOD:
450                 /*
451                  * who knows?  FIXME(eric)
452                  */
453                 return SUCCESS;
454         case BUSY:
455         case QUEUE_FULL:
456         case RESERVATION_CONFLICT:
457         default:
458                 return FAILED;
459         }
460         return FAILED;
461 }
462
463 /**
464  * scsi_eh_done - Completion function for error handling.
465  * @scmd:       Cmd that is done.
466  */
467 static void scsi_eh_done(struct scsi_cmnd *scmd)
468 {
469         struct completion     *eh_action;
470
471         SCSI_LOG_ERROR_RECOVERY(3,
472                 printk("%s scmd: %p result: %x\n",
473                         __FUNCTION__, scmd, scmd->result));
474
475         eh_action = scmd->device->host->eh_action;
476         if (eh_action)
477                 complete(eh_action);
478 }
479
480 /**
481  * scsi_try_host_reset - ask host adapter to reset itself
482  * @scmd:       SCSI cmd to send hsot reset.
483  */
484 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
485 {
486         unsigned long flags;
487         int rtn;
488
489         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
490                                           __FUNCTION__));
491
492         if (!scmd->device->host->hostt->eh_host_reset_handler)
493                 return FAILED;
494
495         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
496
497         if (rtn == SUCCESS) {
498                 if (!scmd->device->host->hostt->skip_settle_delay)
499                         ssleep(HOST_RESET_SETTLE_TIME);
500                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
501                 scsi_report_bus_reset(scmd->device->host,
502                                       scmd_channel(scmd));
503                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
504         }
505
506         return rtn;
507 }
508
509 /**
510  * scsi_try_bus_reset - ask host to perform a bus reset
511  * @scmd:       SCSI cmd to send bus reset.
512  */
513 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
514 {
515         unsigned long flags;
516         int rtn;
517
518         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
519                                           __FUNCTION__));
520
521         if (!scmd->device->host->hostt->eh_bus_reset_handler)
522                 return FAILED;
523
524         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
525
526         if (rtn == SUCCESS) {
527                 if (!scmd->device->host->hostt->skip_settle_delay)
528                         ssleep(BUS_RESET_SETTLE_TIME);
529                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
530                 scsi_report_bus_reset(scmd->device->host,
531                                       scmd_channel(scmd));
532                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
533         }
534
535         return rtn;
536 }
537
538 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
539 {
540         sdev->was_reset = 1;
541         sdev->expecting_cc_ua = 1;
542 }
543
544 /**
545  * scsi_try_target_reset - Ask host to perform a target reset
546  * @scmd:       SCSI cmd used to send a target reset
547  *
548  * Notes:
549  *    There is no timeout for this operation.  if this operation is
550  *    unreliable for a given host, then the host itself needs to put a
551  *    timer on it, and set the host back to a consistent state prior to
552  *    returning.
553  */
554 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
555 {
556         unsigned long flags;
557         int rtn;
558
559         if (!scmd->device->host->hostt->eh_target_reset_handler)
560                 return FAILED;
561
562         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
563         if (rtn == SUCCESS) {
564                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
565                 __starget_for_each_device(scsi_target(scmd->device), NULL,
566                                           __scsi_report_device_reset);
567                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
568         }
569
570         return rtn;
571 }
572
573 /**
574  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
575  * @scmd:       SCSI cmd used to send BDR
576  *
577  * Notes:
578  *    There is no timeout for this operation.  if this operation is
579  *    unreliable for a given host, then the host itself needs to put a
580  *    timer on it, and set the host back to a consistent state prior to
581  *    returning.
582  */
583 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
584 {
585         int rtn;
586
587         if (!scmd->device->host->hostt->eh_device_reset_handler)
588                 return FAILED;
589
590         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
591         if (rtn == SUCCESS)
592                 __scsi_report_device_reset(scmd->device, NULL);
593         return rtn;
594 }
595
596 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
597 {
598         if (!scmd->device->host->hostt->eh_abort_handler)
599                 return FAILED;
600
601         return scmd->device->host->hostt->eh_abort_handler(scmd);
602 }
603
604 /**
605  * scsi_try_to_abort_cmd - Ask host to abort a running command.
606  * @scmd:       SCSI cmd to abort from Lower Level.
607  *
608  * Notes:
609  *    This function will not return until the user's completion function
610  *    has been called.  there is no timeout on this operation.  if the
611  *    author of the low-level driver wishes this operation to be timed,
612  *    they can provide this facility themselves.  helper functions in
613  *    scsi_error.c can be supplied to make this easier to do.
614  */
615 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
616 {
617         /*
618          * scsi_done was called just after the command timed out and before
619          * we had a chance to process it. (db)
620          */
621         if (scmd->serial_number == 0)
622                 return SUCCESS;
623         return __scsi_try_to_abort_cmd(scmd);
624 }
625
626 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
627 {
628         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
629                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
630                         if (scsi_try_target_reset(scmd) != SUCCESS)
631                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
632                                         scsi_try_host_reset(scmd);
633 }
634
635 /**
636  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
637  * @scmd:       SCSI command structure to hijack
638  * @ses:        structure to save restore information
639  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
640  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
641  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
642  *
643  * This function is used to save a scsi command information before re-execution
644  * as part of the error recovery process.  If @sense_bytes is 0 the command
645  * sent must be one that does not transfer any data.  If @sense_bytes != 0
646  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
647  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
648  */
649 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
650                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
651 {
652         struct scsi_device *sdev = scmd->device;
653
654         /*
655          * We need saved copies of a number of fields - this is because
656          * error handling may need to overwrite these with different values
657          * to run different commands, and once error handling is complete,
658          * we will need to restore these values prior to running the actual
659          * command.
660          */
661         ses->cmd_len = scmd->cmd_len;
662         ses->cmnd = scmd->cmnd;
663         ses->data_direction = scmd->sc_data_direction;
664         ses->sdb = scmd->sdb;
665         ses->next_rq = scmd->request->next_rq;
666         ses->result = scmd->result;
667
668         scmd->cmnd = ses->eh_cmnd;
669         memset(scmd->cmnd, 0, BLK_MAX_CDB);
670         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
671         scmd->request->next_rq = NULL;
672
673         if (sense_bytes) {
674                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
675                                          sense_bytes);
676                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
677                             scmd->sdb.length);
678                 scmd->sdb.table.sgl = &ses->sense_sgl;
679                 scmd->sc_data_direction = DMA_FROM_DEVICE;
680                 scmd->sdb.table.nents = 1;
681                 scmd->cmnd[0] = REQUEST_SENSE;
682                 scmd->cmnd[4] = scmd->sdb.length;
683                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
684         } else {
685                 scmd->sc_data_direction = DMA_NONE;
686                 if (cmnd) {
687                         BUG_ON(cmnd_size > BLK_MAX_CDB);
688                         memcpy(scmd->cmnd, cmnd, cmnd_size);
689                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
690                 }
691         }
692
693         scmd->underflow = 0;
694
695         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
696                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
697                         (sdev->lun << 5 & 0xe0);
698
699         /*
700          * Zero the sense buffer.  The scsi spec mandates that any
701          * untransferred sense data should be interpreted as being zero.
702          */
703         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
704 }
705 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
706
707 /**
708  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
709  * @scmd:       SCSI command structure to restore
710  * @ses:        saved information from a coresponding call to scsi_prep_eh_cmnd
711  *
712  * Undo any damage done by above scsi_prep_eh_cmnd().
713  */
714 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
715 {
716         /*
717          * Restore original data
718          */
719         scmd->cmd_len = ses->cmd_len;
720         scmd->cmnd = ses->cmnd;
721         scmd->sc_data_direction = ses->data_direction;
722         scmd->sdb = ses->sdb;
723         scmd->request->next_rq = ses->next_rq;
724         scmd->result = ses->result;
725 }
726 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
727
728 /**
729  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
730  * @scmd:       SCSI command structure to hijack
731  * @cmnd:       CDB to send
732  * @cmnd_size:  size in bytes of @cmnd
733  * @timeout:    timeout for this request
734  * @sense_bytes: size of sense data to copy or 0
735  *
736  * This function is used to send a scsi command down to a target device
737  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
738  *
739  * Return value:
740  *    SUCCESS or FAILED or NEEDS_RETRY
741  */
742 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
743                              int cmnd_size, int timeout, unsigned sense_bytes)
744 {
745         struct scsi_device *sdev = scmd->device;
746         struct Scsi_Host *shost = sdev->host;
747         DECLARE_COMPLETION_ONSTACK(done);
748         unsigned long timeleft;
749         unsigned long flags;
750         struct scsi_eh_save ses;
751         int rtn;
752
753         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
754         shost->eh_action = &done;
755
756         spin_lock_irqsave(shost->host_lock, flags);
757         scsi_log_send(scmd);
758         shost->hostt->queuecommand(scmd, scsi_eh_done);
759         spin_unlock_irqrestore(shost->host_lock, flags);
760
761         timeleft = wait_for_completion_timeout(&done, timeout);
762
763         shost->eh_action = NULL;
764
765         scsi_log_completion(scmd, SUCCESS);
766
767         SCSI_LOG_ERROR_RECOVERY(3,
768                 printk("%s: scmd: %p, timeleft: %ld\n",
769                         __FUNCTION__, scmd, timeleft));
770
771         /*
772          * If there is time left scsi_eh_done got called, and we will
773          * examine the actual status codes to see whether the command
774          * actually did complete normally, else tell the host to forget
775          * about this command.
776          */
777         if (timeleft) {
778                 rtn = scsi_eh_completed_normally(scmd);
779                 SCSI_LOG_ERROR_RECOVERY(3,
780                         printk("%s: scsi_eh_completed_normally %x\n",
781                                __FUNCTION__, rtn));
782
783                 switch (rtn) {
784                 case SUCCESS:
785                 case NEEDS_RETRY:
786                 case FAILED:
787                         break;
788                 default:
789                         rtn = FAILED;
790                         break;
791                 }
792         } else {
793                 scsi_abort_eh_cmnd(scmd);
794                 rtn = FAILED;
795         }
796
797         scsi_eh_restore_cmnd(scmd, &ses);
798         return rtn;
799 }
800
801 /**
802  * scsi_request_sense - Request sense data from a particular target.
803  * @scmd:       SCSI cmd for request sense.
804  *
805  * Notes:
806  *    Some hosts automatically obtain this information, others require
807  *    that we obtain it on our own. This function will *not* return until
808  *    the command either times out, or it completes.
809  */
810 static int scsi_request_sense(struct scsi_cmnd *scmd)
811 {
812         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
813 }
814
815 /**
816  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
817  * @scmd:       Original SCSI cmd that eh has finished.
818  * @done_q:     Queue for processed commands.
819  *
820  * Notes:
821  *    We don't want to use the normal command completion while we are are
822  *    still handling errors - it may cause other commands to be queued,
823  *    and that would disturb what we are doing.  Thus we really want to
824  *    keep a list of pending commands for final completion, and once we
825  *    are ready to leave error handling we handle completion for real.
826  */
827 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
828 {
829         scmd->device->host->host_failed--;
830         scmd->eh_eflags = 0;
831         list_move_tail(&scmd->eh_entry, done_q);
832 }
833 EXPORT_SYMBOL(scsi_eh_finish_cmd);
834
835 /**
836  * scsi_eh_get_sense - Get device sense data.
837  * @work_q:     Queue of commands to process.
838  * @done_q:     Queue of processed commands.
839  *
840  * Description:
841  *    See if we need to request sense information.  if so, then get it
842  *    now, so we have a better idea of what to do.  
843  *
844  * Notes:
845  *    This has the unfortunate side effect that if a shost adapter does
846  *    not automatically request sense information, we end up shutting
847  *    it down before we request it.
848  *
849  *    All drivers should request sense information internally these days,
850  *    so for now all I have to say is tough noogies if you end up in here.
851  *
852  *    XXX: Long term this code should go away, but that needs an audit of
853  *         all LLDDs first.
854  */
855 int scsi_eh_get_sense(struct list_head *work_q,
856                       struct list_head *done_q)
857 {
858         struct scsi_cmnd *scmd, *next;
859         int rtn;
860
861         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
862                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
863                     SCSI_SENSE_VALID(scmd))
864                         continue;
865
866                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
867                                                   "%s: requesting sense\n",
868                                                   current->comm));
869                 rtn = scsi_request_sense(scmd);
870                 if (rtn != SUCCESS)
871                         continue;
872
873                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
874                                                   " result %x\n", scmd,
875                                                   scmd->result));
876                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
877
878                 rtn = scsi_decide_disposition(scmd);
879
880                 /*
881                  * if the result was normal, then just pass it along to the
882                  * upper level.
883                  */
884                 if (rtn == SUCCESS)
885                         /* we don't want this command reissued, just
886                          * finished with the sense data, so set
887                          * retries to the max allowed to ensure it
888                          * won't get reissued */
889                         scmd->retries = scmd->allowed;
890                 else if (rtn != NEEDS_RETRY)
891                         continue;
892
893                 scsi_eh_finish_cmd(scmd, done_q);
894         }
895
896         return list_empty(work_q);
897 }
898 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
899
900 /**
901  * scsi_eh_tur - Send TUR to device.
902  * @scmd:       &scsi_cmnd to send TUR
903  *
904  * Return value:
905  *    0 - Device is ready. 1 - Device NOT ready.
906  */
907 static int scsi_eh_tur(struct scsi_cmnd *scmd)
908 {
909         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
910         int retry_cnt = 1, rtn;
911
912 retry_tur:
913         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
914
915         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
916                 __FUNCTION__, scmd, rtn));
917
918         switch (rtn) {
919         case NEEDS_RETRY:
920                 if (retry_cnt--)
921                         goto retry_tur;
922                 /*FALLTHRU*/
923         case SUCCESS:
924                 return 0;
925         default:
926                 return 1;
927         }
928 }
929
930 /**
931  * scsi_eh_abort_cmds - abort pending commands.
932  * @work_q:     &list_head for pending commands.
933  * @done_q:     &list_head for processed commands.
934  *
935  * Decription:
936  *    Try and see whether or not it makes sense to try and abort the
937  *    running command.  This only works out to be the case if we have one
938  *    command that has timed out.  If the command simply failed, it makes
939  *    no sense to try and abort the command, since as far as the shost
940  *    adapter is concerned, it isn't running.
941  */
942 static int scsi_eh_abort_cmds(struct list_head *work_q,
943                               struct list_head *done_q)
944 {
945         struct scsi_cmnd *scmd, *next;
946         int rtn;
947
948         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
949                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
950                         continue;
951                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
952                                                   "0x%p\n", current->comm,
953                                                   scmd));
954                 rtn = scsi_try_to_abort_cmd(scmd);
955                 if (rtn == SUCCESS) {
956                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
957                         if (!scsi_device_online(scmd->device) ||
958                             !scsi_eh_tur(scmd)) {
959                                 scsi_eh_finish_cmd(scmd, done_q);
960                         }
961                                 
962                 } else
963                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
964                                                           " cmd failed:"
965                                                           "0x%p\n",
966                                                           current->comm,
967                                                           scmd));
968         }
969
970         return list_empty(work_q);
971 }
972
973 /**
974  * scsi_eh_try_stu - Send START_UNIT to device.
975  * @scmd:       &scsi_cmnd to send START_UNIT
976  *
977  * Return value:
978  *    0 - Device is ready. 1 - Device NOT ready.
979  */
980 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
981 {
982         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
983
984         if (scmd->device->allow_restart) {
985                 int i, rtn = NEEDS_RETRY;
986
987                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
988                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
989                                                 scmd->device->timeout, 0);
990
991                 if (rtn == SUCCESS)
992                         return 0;
993         }
994
995         return 1;
996 }
997
998  /**
999  * scsi_eh_stu - send START_UNIT if needed
1000  * @shost:      &scsi host being recovered.
1001  * @work_q:     &list_head for pending commands.
1002  * @done_q:     &list_head for processed commands.
1003  *
1004  * Notes:
1005  *    If commands are failing due to not ready, initializing command required,
1006  *      try revalidating the device, which will end up sending a start unit. 
1007  */
1008 static int scsi_eh_stu(struct Scsi_Host *shost,
1009                               struct list_head *work_q,
1010                               struct list_head *done_q)
1011 {
1012         struct scsi_cmnd *scmd, *stu_scmd, *next;
1013         struct scsi_device *sdev;
1014
1015         shost_for_each_device(sdev, shost) {
1016                 stu_scmd = NULL;
1017                 list_for_each_entry(scmd, work_q, eh_entry)
1018                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1019                             scsi_check_sense(scmd) == FAILED ) {
1020                                 stu_scmd = scmd;
1021                                 break;
1022                         }
1023
1024                 if (!stu_scmd)
1025                         continue;
1026
1027                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1028                                                   " 0x%p\n", current->comm, sdev));
1029
1030                 if (!scsi_eh_try_stu(stu_scmd)) {
1031                         if (!scsi_device_online(sdev) ||
1032                             !scsi_eh_tur(stu_scmd)) {
1033                                 list_for_each_entry_safe(scmd, next,
1034                                                           work_q, eh_entry) {
1035                                         if (scmd->device == sdev)
1036                                                 scsi_eh_finish_cmd(scmd, done_q);
1037                                 }
1038                         }
1039                 } else {
1040                         SCSI_LOG_ERROR_RECOVERY(3,
1041                                                 printk("%s: START_UNIT failed to sdev:"
1042                                                        " 0x%p\n", current->comm, sdev));
1043                 }
1044         }
1045
1046         return list_empty(work_q);
1047 }
1048
1049
1050 /**
1051  * scsi_eh_bus_device_reset - send bdr if needed
1052  * @shost:      scsi host being recovered.
1053  * @work_q:     &list_head for pending commands.
1054  * @done_q:     &list_head for processed commands.
1055  *
1056  * Notes:
1057  *    Try a bus device reset.  Still, look to see whether we have multiple
1058  *    devices that are jammed or not - if we have multiple devices, it
1059  *    makes no sense to try bus_device_reset - we really would need to try
1060  *    a bus_reset instead. 
1061  */
1062 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1063                                     struct list_head *work_q,
1064                                     struct list_head *done_q)
1065 {
1066         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1067         struct scsi_device *sdev;
1068         int rtn;
1069
1070         shost_for_each_device(sdev, shost) {
1071                 bdr_scmd = NULL;
1072                 list_for_each_entry(scmd, work_q, eh_entry)
1073                         if (scmd->device == sdev) {
1074                                 bdr_scmd = scmd;
1075                                 break;
1076                         }
1077
1078                 if (!bdr_scmd)
1079                         continue;
1080
1081                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1082                                                   " 0x%p\n", current->comm,
1083                                                   sdev));
1084                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1085                 if (rtn == SUCCESS) {
1086                         if (!scsi_device_online(sdev) ||
1087                             !scsi_eh_tur(bdr_scmd)) {
1088                                 list_for_each_entry_safe(scmd, next,
1089                                                          work_q, eh_entry) {
1090                                         if (scmd->device == sdev)
1091                                                 scsi_eh_finish_cmd(scmd,
1092                                                                    done_q);
1093                                 }
1094                         }
1095                 } else {
1096                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1097                                                           " failed sdev:"
1098                                                           "0x%p\n",
1099                                                           current->comm,
1100                                                            sdev));
1101                 }
1102         }
1103
1104         return list_empty(work_q);
1105 }
1106
1107 /**
1108  * scsi_eh_target_reset - send target reset if needed
1109  * @shost:      scsi host being recovered.
1110  * @work_q:     &list_head for pending commands.
1111  * @done_q:     &list_head for processed commands.
1112  *
1113  * Notes:
1114  *    Try a target reset.
1115  */
1116 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1117                                 struct list_head *work_q,
1118                                 struct list_head *done_q)
1119 {
1120         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1121         unsigned int id;
1122         int rtn;
1123
1124         for (id = 0; id <= shost->max_id; id++) {
1125                 tgtr_scmd = NULL;
1126                 list_for_each_entry(scmd, work_q, eh_entry) {
1127                         if (id == scmd_id(scmd)) {
1128                                 tgtr_scmd = scmd;
1129                                 break;
1130                         }
1131                 }
1132                 if (!tgtr_scmd)
1133                         continue;
1134
1135                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1136                                                   "to target %d\n",
1137                                                   current->comm, id));
1138                 rtn = scsi_try_target_reset(tgtr_scmd);
1139                 if (rtn == SUCCESS) {
1140                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1141                                 if (id == scmd_id(scmd))
1142                                         if (!scsi_device_online(scmd->device) ||
1143                                             !scsi_eh_tur(tgtr_scmd))
1144                                                 scsi_eh_finish_cmd(scmd,
1145                                                                    done_q);
1146                         }
1147                 } else
1148                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1149                                                           " failed target: "
1150                                                           "%d\n",
1151                                                           current->comm, id));
1152         }
1153
1154         return list_empty(work_q);
1155 }
1156
1157 /**
1158  * scsi_eh_bus_reset - send a bus reset 
1159  * @shost:      &scsi host being recovered.
1160  * @work_q:     &list_head for pending commands.
1161  * @done_q:     &list_head for processed commands.
1162  */
1163 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1164                              struct list_head *work_q,
1165                              struct list_head *done_q)
1166 {
1167         struct scsi_cmnd *scmd, *chan_scmd, *next;
1168         unsigned int channel;
1169         int rtn;
1170
1171         /*
1172          * we really want to loop over the various channels, and do this on
1173          * a channel by channel basis.  we should also check to see if any
1174          * of the failed commands are on soft_reset devices, and if so, skip
1175          * the reset.  
1176          */
1177
1178         for (channel = 0; channel <= shost->max_channel; channel++) {
1179                 chan_scmd = NULL;
1180                 list_for_each_entry(scmd, work_q, eh_entry) {
1181                         if (channel == scmd_channel(scmd)) {
1182                                 chan_scmd = scmd;
1183                                 break;
1184                                 /*
1185                                  * FIXME add back in some support for
1186                                  * soft_reset devices.
1187                                  */
1188                         }
1189                 }
1190
1191                 if (!chan_scmd)
1192                         continue;
1193                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1194                                                   " %d\n", current->comm,
1195                                                   channel));
1196                 rtn = scsi_try_bus_reset(chan_scmd);
1197                 if (rtn == SUCCESS) {
1198                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1199                                 if (channel == scmd_channel(scmd))
1200                                         if (!scsi_device_online(scmd->device) ||
1201                                             !scsi_eh_tur(scmd))
1202                                                 scsi_eh_finish_cmd(scmd,
1203                                                                    done_q);
1204                         }
1205                 } else {
1206                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1207                                                           " failed chan: %d\n",
1208                                                           current->comm,
1209                                                           channel));
1210                 }
1211         }
1212         return list_empty(work_q);
1213 }
1214
1215 /**
1216  * scsi_eh_host_reset - send a host reset 
1217  * @work_q:     list_head for processed commands.
1218  * @done_q:     list_head for processed commands.
1219  */
1220 static int scsi_eh_host_reset(struct list_head *work_q,
1221                               struct list_head *done_q)
1222 {
1223         struct scsi_cmnd *scmd, *next;
1224         int rtn;
1225
1226         if (!list_empty(work_q)) {
1227                 scmd = list_entry(work_q->next,
1228                                   struct scsi_cmnd, eh_entry);
1229
1230                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1231                                                   , current->comm));
1232
1233                 rtn = scsi_try_host_reset(scmd);
1234                 if (rtn == SUCCESS) {
1235                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1236                                 if (!scsi_device_online(scmd->device) ||
1237                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1238                                     !scsi_eh_tur(scmd))
1239                                         scsi_eh_finish_cmd(scmd, done_q);
1240                         }
1241                 } else {
1242                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1243                                                           " failed\n",
1244                                                           current->comm));
1245                 }
1246         }
1247         return list_empty(work_q);
1248 }
1249
1250 /**
1251  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1252  * @work_q:     list_head for processed commands.
1253  * @done_q:     list_head for processed commands.
1254  */
1255 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1256                                   struct list_head *done_q)
1257 {
1258         struct scsi_cmnd *scmd, *next;
1259
1260         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1261                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1262                             "not ready after error recovery\n");
1263                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1264                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1265                         /*
1266                          * FIXME: Handle lost cmds.
1267                          */
1268                 }
1269                 scsi_eh_finish_cmd(scmd, done_q);
1270         }
1271         return;
1272 }
1273
1274 /**
1275  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1276  * @scmd:       SCSI cmd to examine.
1277  *
1278  * Notes:
1279  *    This is *only* called when we are examining the status after sending
1280  *    out the actual data command.  any commands that are queued for error
1281  *    recovery (e.g. test_unit_ready) do *not* come through here.
1282  *
1283  *    When this routine returns failed, it means the error handler thread
1284  *    is woken.  In cases where the error code indicates an error that
1285  *    doesn't require the error handler read (i.e. we don't need to
1286  *    abort/reset), this function should return SUCCESS.
1287  */
1288 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1289 {
1290         int rtn;
1291
1292         /*
1293          * if the device is offline, then we clearly just pass the result back
1294          * up to the top level.
1295          */
1296         if (!scsi_device_online(scmd->device)) {
1297                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1298                                                   " as SUCCESS\n",
1299                                                   __FUNCTION__));
1300                 return SUCCESS;
1301         }
1302
1303         /*
1304          * first check the host byte, to see if there is anything in there
1305          * that would indicate what we need to do.
1306          */
1307         switch (host_byte(scmd->result)) {
1308         case DID_PASSTHROUGH:
1309                 /*
1310                  * no matter what, pass this through to the upper layer.
1311                  * nuke this special code so that it looks like we are saying
1312                  * did_ok.
1313                  */
1314                 scmd->result &= 0xff00ffff;
1315                 return SUCCESS;
1316         case DID_OK:
1317                 /*
1318                  * looks good.  drop through, and check the next byte.
1319                  */
1320                 break;
1321         case DID_NO_CONNECT:
1322         case DID_BAD_TARGET:
1323         case DID_ABORT:
1324                 /*
1325                  * note - this means that we just report the status back
1326                  * to the top level driver, not that we actually think
1327                  * that it indicates SUCCESS.
1328                  */
1329                 return SUCCESS;
1330                 /*
1331                  * when the low level driver returns did_soft_error,
1332                  * it is responsible for keeping an internal retry counter 
1333                  * in order to avoid endless loops (db)
1334                  *
1335                  * actually this is a bug in this function here.  we should
1336                  * be mindful of the maximum number of retries specified
1337                  * and not get stuck in a loop.
1338                  */
1339         case DID_SOFT_ERROR:
1340                 goto maybe_retry;
1341         case DID_IMM_RETRY:
1342                 return NEEDS_RETRY;
1343
1344         case DID_REQUEUE:
1345                 return ADD_TO_MLQUEUE;
1346
1347         case DID_ERROR:
1348                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1349                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1350                         /*
1351                          * execute reservation conflict processing code
1352                          * lower down
1353                          */
1354                         break;
1355                 /* fallthrough */
1356
1357         case DID_BUS_BUSY:
1358         case DID_PARITY:
1359                 goto maybe_retry;
1360         case DID_TIME_OUT:
1361                 /*
1362                  * when we scan the bus, we get timeout messages for
1363                  * these commands if there is no device available.
1364                  * other hosts report did_no_connect for the same thing.
1365                  */
1366                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1367                      scmd->cmnd[0] == INQUIRY)) {
1368                         return SUCCESS;
1369                 } else {
1370                         return FAILED;
1371                 }
1372         case DID_RESET:
1373                 return SUCCESS;
1374         default:
1375                 return FAILED;
1376         }
1377
1378         /*
1379          * next, check the message byte.
1380          */
1381         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1382                 return FAILED;
1383
1384         /*
1385          * check the status byte to see if this indicates anything special.
1386          */
1387         switch (status_byte(scmd->result)) {
1388         case QUEUE_FULL:
1389                 /*
1390                  * the case of trying to send too many commands to a
1391                  * tagged queueing device.
1392                  */
1393         case BUSY:
1394                 /*
1395                  * device can't talk to us at the moment.  Should only
1396                  * occur (SAM-3) when the task queue is empty, so will cause
1397                  * the empty queue handling to trigger a stall in the
1398                  * device.
1399                  */
1400                 return ADD_TO_MLQUEUE;
1401         case GOOD:
1402         case COMMAND_TERMINATED:
1403         case TASK_ABORTED:
1404                 return SUCCESS;
1405         case CHECK_CONDITION:
1406                 rtn = scsi_check_sense(scmd);
1407                 if (rtn == NEEDS_RETRY)
1408                         goto maybe_retry;
1409                 /* if rtn == FAILED, we have no sense information;
1410                  * returning FAILED will wake the error handler thread
1411                  * to collect the sense and redo the decide
1412                  * disposition */
1413                 return rtn;
1414         case CONDITION_GOOD:
1415         case INTERMEDIATE_GOOD:
1416         case INTERMEDIATE_C_GOOD:
1417         case ACA_ACTIVE:
1418                 /*
1419                  * who knows?  FIXME(eric)
1420                  */
1421                 return SUCCESS;
1422
1423         case RESERVATION_CONFLICT:
1424                 sdev_printk(KERN_INFO, scmd->device,
1425                             "reservation conflict\n");
1426                 return SUCCESS; /* causes immediate i/o error */
1427         default:
1428                 return FAILED;
1429         }
1430         return FAILED;
1431
1432       maybe_retry:
1433
1434         /* we requeue for retry because the error was retryable, and
1435          * the request was not marked fast fail.  Note that above,
1436          * even if the request is marked fast fail, we still requeue
1437          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1438         if ((++scmd->retries) <= scmd->allowed
1439             && !blk_noretry_request(scmd->request)) {
1440                 return NEEDS_RETRY;
1441         } else {
1442                 /*
1443                  * no more retries - report this one back to upper level.
1444                  */
1445                 return SUCCESS;
1446         }
1447 }
1448
1449 /**
1450  * scsi_eh_lock_door - Prevent medium removal for the specified device
1451  * @sdev:       SCSI device to prevent medium removal
1452  *
1453  * Locking:
1454  *      We must be called from process context; scsi_allocate_request()
1455  *      may sleep.
1456  *
1457  * Notes:
1458  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1459  *      head of the devices request queue, and continue.
1460  *
1461  * Bugs:
1462  *      scsi_allocate_request() may sleep waiting for existing requests to
1463  *      be processed.  However, since we haven't kicked off any request
1464  *      processing for this host, this may deadlock.
1465  *
1466  *      If scsi_allocate_request() fails for what ever reason, we
1467  *      completely forget to lock the door.
1468  */
1469 static void scsi_eh_lock_door(struct scsi_device *sdev)
1470 {
1471         unsigned char cmnd[MAX_COMMAND_SIZE];
1472
1473         cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1474         cmnd[1] = 0;
1475         cmnd[2] = 0;
1476         cmnd[3] = 0;
1477         cmnd[4] = SCSI_REMOVAL_PREVENT;
1478         cmnd[5] = 0;
1479
1480         scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1481                            5, NULL, NULL, GFP_KERNEL);
1482 }
1483
1484
1485 /**
1486  * scsi_restart_operations - restart io operations to the specified host.
1487  * @shost:      Host we are restarting.
1488  *
1489  * Notes:
1490  *    When we entered the error handler, we blocked all further i/o to
1491  *    this device.  we need to 'reverse' this process.
1492  */
1493 static void scsi_restart_operations(struct Scsi_Host *shost)
1494 {
1495         struct scsi_device *sdev;
1496         unsigned long flags;
1497
1498         /*
1499          * If the door was locked, we need to insert a door lock request
1500          * onto the head of the SCSI request queue for the device.  There
1501          * is no point trying to lock the door of an off-line device.
1502          */
1503         shost_for_each_device(sdev, shost) {
1504                 if (scsi_device_online(sdev) && sdev->locked)
1505                         scsi_eh_lock_door(sdev);
1506         }
1507
1508         /*
1509          * next free up anything directly waiting upon the host.  this
1510          * will be requests for character device operations, and also for
1511          * ioctls to queued block devices.
1512          */
1513         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1514                                           __FUNCTION__));
1515
1516         spin_lock_irqsave(shost->host_lock, flags);
1517         if (scsi_host_set_state(shost, SHOST_RUNNING))
1518                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1519                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1520         spin_unlock_irqrestore(shost->host_lock, flags);
1521
1522         wake_up(&shost->host_wait);
1523
1524         /*
1525          * finally we need to re-initiate requests that may be pending.  we will
1526          * have had everything blocked while error handling is taking place, and
1527          * now that error recovery is done, we will need to ensure that these
1528          * requests are started.
1529          */
1530         scsi_run_host_queues(shost);
1531 }
1532
1533 /**
1534  * scsi_eh_ready_devs - check device ready state and recover if not.
1535  * @shost:      host to be recovered.
1536  * @work_q:     &list_head for pending commands.
1537  * @done_q:     &list_head for processed commands.
1538  */
1539 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1540                         struct list_head *work_q,
1541                         struct list_head *done_q)
1542 {
1543         if (!scsi_eh_stu(shost, work_q, done_q))
1544                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1545                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1546                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1547                                         if (!scsi_eh_host_reset(work_q, done_q))
1548                                                 scsi_eh_offline_sdevs(work_q,
1549                                                                       done_q);
1550 }
1551 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1552
1553 /**
1554  * scsi_eh_flush_done_q - finish processed commands or retry them.
1555  * @done_q:     list_head of processed commands.
1556  */
1557 void scsi_eh_flush_done_q(struct list_head *done_q)
1558 {
1559         struct scsi_cmnd *scmd, *next;
1560
1561         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1562                 list_del_init(&scmd->eh_entry);
1563                 if (scsi_device_online(scmd->device) &&
1564                     !blk_noretry_request(scmd->request) &&
1565                     (++scmd->retries <= scmd->allowed)) {
1566                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1567                                                           " retry cmd: %p\n",
1568                                                           current->comm,
1569                                                           scmd));
1570                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1571                 } else {
1572                         /*
1573                          * If just we got sense for the device (called
1574                          * scsi_eh_get_sense), scmd->result is already
1575                          * set, do not set DRIVER_TIMEOUT.
1576                          */
1577                         if (!scmd->result)
1578                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1579                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1580                                                         " cmd: %p\n",
1581                                                         current->comm, scmd));
1582                         scsi_finish_command(scmd);
1583                 }
1584         }
1585 }
1586 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1587
1588 /**
1589  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1590  * @shost:      Host to unjam.
1591  *
1592  * Notes:
1593  *    When we come in here, we *know* that all commands on the bus have
1594  *    either completed, failed or timed out.  we also know that no further
1595  *    commands are being sent to the host, so things are relatively quiet
1596  *    and we have freedom to fiddle with things as we wish.
1597  *
1598  *    This is only the *default* implementation.  it is possible for
1599  *    individual drivers to supply their own version of this function, and
1600  *    if the maintainer wishes to do this, it is strongly suggested that
1601  *    this function be taken as a template and modified.  this function
1602  *    was designed to correctly handle problems for about 95% of the
1603  *    different cases out there, and it should always provide at least a
1604  *    reasonable amount of error recovery.
1605  *
1606  *    Any command marked 'failed' or 'timeout' must eventually have
1607  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1608  *    here, so when we restart the host after we return it should have an
1609  *    empty queue.
1610  */
1611 static void scsi_unjam_host(struct Scsi_Host *shost)
1612 {
1613         unsigned long flags;
1614         LIST_HEAD(eh_work_q);
1615         LIST_HEAD(eh_done_q);
1616
1617         spin_lock_irqsave(shost->host_lock, flags);
1618         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1619         spin_unlock_irqrestore(shost->host_lock, flags);
1620
1621         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1622
1623         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1624                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1625                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1626
1627         scsi_eh_flush_done_q(&eh_done_q);
1628 }
1629
1630 /**
1631  * scsi_error_handler - SCSI error handler thread
1632  * @data:       Host for which we are running.
1633  *
1634  * Notes:
1635  *    This is the main error handling loop.  This is run as a kernel thread
1636  *    for every SCSI host and handles all error handling activity.
1637  */
1638 int scsi_error_handler(void *data)
1639 {
1640         struct Scsi_Host *shost = data;
1641
1642         /*
1643          * We use TASK_INTERRUPTIBLE so that the thread is not
1644          * counted against the load average as a running process.
1645          * We never actually get interrupted because kthread_run
1646          * disables singal delivery for the created thread.
1647          */
1648         set_current_state(TASK_INTERRUPTIBLE);
1649         while (!kthread_should_stop()) {
1650                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1651                     shost->host_failed != shost->host_busy) {
1652                         SCSI_LOG_ERROR_RECOVERY(1,
1653                                 printk("Error handler scsi_eh_%d sleeping\n",
1654                                         shost->host_no));
1655                         schedule();
1656                         set_current_state(TASK_INTERRUPTIBLE);
1657                         continue;
1658                 }
1659
1660                 __set_current_state(TASK_RUNNING);
1661                 SCSI_LOG_ERROR_RECOVERY(1,
1662                         printk("Error handler scsi_eh_%d waking up\n",
1663                                 shost->host_no));
1664
1665                 /*
1666                  * We have a host that is failing for some reason.  Figure out
1667                  * what we need to do to get it up and online again (if we can).
1668                  * If we fail, we end up taking the thing offline.
1669                  */
1670                 if (shost->transportt->eh_strategy_handler)
1671                         shost->transportt->eh_strategy_handler(shost);
1672                 else
1673                         scsi_unjam_host(shost);
1674
1675                 /*
1676                  * Note - if the above fails completely, the action is to take
1677                  * individual devices offline and flush the queue of any
1678                  * outstanding requests that may have been pending.  When we
1679                  * restart, we restart any I/O to any other devices on the bus
1680                  * which are still online.
1681                  */
1682                 scsi_restart_operations(shost);
1683                 set_current_state(TASK_INTERRUPTIBLE);
1684         }
1685         __set_current_state(TASK_RUNNING);
1686
1687         SCSI_LOG_ERROR_RECOVERY(1,
1688                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1689         shost->ehandler = NULL;
1690         return 0;
1691 }
1692
1693 /*
1694  * Function:    scsi_report_bus_reset()
1695  *
1696  * Purpose:     Utility function used by low-level drivers to report that
1697  *              they have observed a bus reset on the bus being handled.
1698  *
1699  * Arguments:   shost       - Host in question
1700  *              channel     - channel on which reset was observed.
1701  *
1702  * Returns:     Nothing
1703  *
1704  * Lock status: Host lock must be held.
1705  *
1706  * Notes:       This only needs to be called if the reset is one which
1707  *              originates from an unknown location.  Resets originated
1708  *              by the mid-level itself don't need to call this, but there
1709  *              should be no harm.
1710  *
1711  *              The main purpose of this is to make sure that a CHECK_CONDITION
1712  *              is properly treated.
1713  */
1714 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1715 {
1716         struct scsi_device *sdev;
1717
1718         __shost_for_each_device(sdev, shost) {
1719                 if (channel == sdev_channel(sdev))
1720                         __scsi_report_device_reset(sdev, NULL);
1721         }
1722 }
1723 EXPORT_SYMBOL(scsi_report_bus_reset);
1724
1725 /*
1726  * Function:    scsi_report_device_reset()
1727  *
1728  * Purpose:     Utility function used by low-level drivers to report that
1729  *              they have observed a device reset on the device being handled.
1730  *
1731  * Arguments:   shost       - Host in question
1732  *              channel     - channel on which reset was observed
1733  *              target      - target 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_device_reset(struct Scsi_Host *shost, int channel, int target)
1748 {
1749         struct scsi_device *sdev;
1750
1751         __shost_for_each_device(sdev, shost) {
1752                 if (channel == sdev_channel(sdev) &&
1753                     target == sdev_id(sdev))
1754                         __scsi_report_device_reset(sdev, NULL);
1755         }
1756 }
1757 EXPORT_SYMBOL(scsi_report_device_reset);
1758
1759 static void
1760 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1761 {
1762 }
1763
1764 /*
1765  * Function:    scsi_reset_provider
1766  *
1767  * Purpose:     Send requested reset to a bus or device at any phase.
1768  *
1769  * Arguments:   device  - device to send reset to
1770  *              flag - reset type (see scsi.h)
1771  *
1772  * Returns:     SUCCESS/FAILURE.
1773  *
1774  * Notes:       This is used by the SCSI Generic driver to provide
1775  *              Bus/Device reset capability.
1776  */
1777 int
1778 scsi_reset_provider(struct scsi_device *dev, int flag)
1779 {
1780         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1781         struct Scsi_Host *shost = dev->host;
1782         struct request req;
1783         unsigned long flags;
1784         int rtn;
1785
1786         blk_rq_init(NULL, &req);
1787         scmd->request = &req;
1788         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1789
1790         scmd->cmnd = req.cmd;
1791
1792         scmd->scsi_done         = scsi_reset_provider_done_command;
1793         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1794
1795         scmd->cmd_len                   = 0;
1796
1797         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1798
1799         init_timer(&scmd->eh_timeout);
1800
1801         spin_lock_irqsave(shost->host_lock, flags);
1802         shost->tmf_in_progress = 1;
1803         spin_unlock_irqrestore(shost->host_lock, flags);
1804
1805         switch (flag) {
1806         case SCSI_TRY_RESET_DEVICE:
1807                 rtn = scsi_try_bus_device_reset(scmd);
1808                 if (rtn == SUCCESS)
1809                         break;
1810                 /* FALLTHROUGH */
1811         case SCSI_TRY_RESET_TARGET:
1812                 rtn = scsi_try_target_reset(scmd);
1813                 if (rtn == SUCCESS)
1814                         break;
1815                 /* FALLTHROUGH */
1816         case SCSI_TRY_RESET_BUS:
1817                 rtn = scsi_try_bus_reset(scmd);
1818                 if (rtn == SUCCESS)
1819                         break;
1820                 /* FALLTHROUGH */
1821         case SCSI_TRY_RESET_HOST:
1822                 rtn = scsi_try_host_reset(scmd);
1823                 break;
1824         default:
1825                 rtn = FAILED;
1826         }
1827
1828         spin_lock_irqsave(shost->host_lock, flags);
1829         shost->tmf_in_progress = 0;
1830         spin_unlock_irqrestore(shost->host_lock, flags);
1831
1832         /*
1833          * be sure to wake up anyone who was sleeping or had their queue
1834          * suspended while we performed the TMF.
1835          */
1836         SCSI_LOG_ERROR_RECOVERY(3,
1837                 printk("%s: waking up host to restart after TMF\n",
1838                 __FUNCTION__));
1839
1840         wake_up(&shost->host_wait);
1841
1842         scsi_run_host_queues(shost);
1843
1844         scsi_next_command(scmd);
1845         return rtn;
1846 }
1847 EXPORT_SYMBOL(scsi_reset_provider);
1848
1849 /**
1850  * scsi_normalize_sense - normalize main elements from either fixed or
1851  *                      descriptor sense data format into a common format.
1852  *
1853  * @sense_buffer:       byte array containing sense data returned by device
1854  * @sb_len:             number of valid bytes in sense_buffer
1855  * @sshdr:              pointer to instance of structure that common
1856  *                      elements are written to.
1857  *
1858  * Notes:
1859  *      The "main elements" from sense data are: response_code, sense_key,
1860  *      asc, ascq and additional_length (only for descriptor format).
1861  *
1862  *      Typically this function can be called after a device has
1863  *      responded to a SCSI command with the CHECK_CONDITION status.
1864  *
1865  * Return value:
1866  *      1 if valid sense data information found, else 0;
1867  */
1868 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1869                          struct scsi_sense_hdr *sshdr)
1870 {
1871         if (!sense_buffer || !sb_len)
1872                 return 0;
1873
1874         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1875
1876         sshdr->response_code = (sense_buffer[0] & 0x7f);
1877
1878         if (!scsi_sense_valid(sshdr))
1879                 return 0;
1880
1881         if (sshdr->response_code >= 0x72) {
1882                 /*
1883                  * descriptor format
1884                  */
1885                 if (sb_len > 1)
1886                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1887                 if (sb_len > 2)
1888                         sshdr->asc = sense_buffer[2];
1889                 if (sb_len > 3)
1890                         sshdr->ascq = sense_buffer[3];
1891                 if (sb_len > 7)
1892                         sshdr->additional_length = sense_buffer[7];
1893         } else {
1894                 /* 
1895                  * fixed format
1896                  */
1897                 if (sb_len > 2)
1898                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1899                 if (sb_len > 7) {
1900                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1901                                          sb_len : (sense_buffer[7] + 8);
1902                         if (sb_len > 12)
1903                                 sshdr->asc = sense_buffer[12];
1904                         if (sb_len > 13)
1905                                 sshdr->ascq = sense_buffer[13];
1906                 }
1907         }
1908
1909         return 1;
1910 }
1911 EXPORT_SYMBOL(scsi_normalize_sense);
1912
1913 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1914                                  struct scsi_sense_hdr *sshdr)
1915 {
1916         return scsi_normalize_sense(cmd->sense_buffer,
1917                         SCSI_SENSE_BUFFERSIZE, sshdr);
1918 }
1919 EXPORT_SYMBOL(scsi_command_normalize_sense);
1920
1921 /**
1922  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1923  * @sense_buffer:       byte array of descriptor format sense data
1924  * @sb_len:             number of valid bytes in sense_buffer
1925  * @desc_type:          value of descriptor type to find
1926  *                      (e.g. 0 -> information)
1927  *
1928  * Notes:
1929  *      only valid when sense data is in descriptor format
1930  *
1931  * Return value:
1932  *      pointer to start of (first) descriptor if found else NULL
1933  */
1934 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1935                                 int desc_type)
1936 {
1937         int add_sen_len, add_len, desc_len, k;
1938         const u8 * descp;
1939
1940         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1941                 return NULL;
1942         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1943                 return NULL;
1944         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1945                         add_sen_len : (sb_len - 8);
1946         descp = &sense_buffer[8];
1947         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1948                 descp += desc_len;
1949                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1950                 desc_len = add_len + 2;
1951                 if (descp[0] == desc_type)
1952                         return descp;
1953                 if (add_len < 0) // short descriptor ??
1954                         break;
1955         }
1956         return NULL;
1957 }
1958 EXPORT_SYMBOL(scsi_sense_desc_find);
1959
1960 /**
1961  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
1962  * @sense_buffer:       byte array of sense data
1963  * @sb_len:             number of valid bytes in sense_buffer
1964  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1965  *                      field will be placed if found.
1966  *
1967  * Return value:
1968  *      1 if information field found, 0 if not found.
1969  */
1970 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1971                             u64 * info_out)
1972 {
1973         int j;
1974         const u8 * ucp;
1975         u64 ull;
1976
1977         if (sb_len < 7)
1978                 return 0;
1979         switch (sense_buffer[0] & 0x7f) {
1980         case 0x70:
1981         case 0x71:
1982                 if (sense_buffer[0] & 0x80) {
1983                         *info_out = (sense_buffer[3] << 24) +
1984                                     (sense_buffer[4] << 16) +
1985                                     (sense_buffer[5] << 8) + sense_buffer[6];
1986                         return 1;
1987                 } else
1988                         return 0;
1989         case 0x72:
1990         case 0x73:
1991                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1992                                            0 /* info desc */);
1993                 if (ucp && (0xa == ucp[1])) {
1994                         ull = 0;
1995                         for (j = 0; j < 8; ++j) {
1996                                 if (j > 0)
1997                                         ull <<= 8;
1998                                 ull |= ucp[4 + j];
1999                         }
2000                         *info_out = ull;
2001                         return 1;
2002                 } else
2003                         return 0;
2004         default:
2005                 return 0;
2006         }
2007 }
2008 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2009
2010 /**
2011  * scsi_build_sense_buffer - build sense data in a buffer
2012  * @desc:       Sense format (non zero == descriptor format,
2013  *              0 == fixed format)
2014  * @buf:        Where to build sense data
2015  * @key:        Sense key
2016  * @asc:        Additional sense code
2017  * @ascq:       Additional sense code qualifier
2018  *
2019  **/
2020 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2021 {
2022         if (desc) {
2023                 buf[0] = 0x72;  /* descriptor, current */
2024                 buf[1] = key;
2025                 buf[2] = asc;
2026                 buf[3] = ascq;
2027                 buf[7] = 0;
2028         } else {
2029                 buf[0] = 0x70;  /* fixed, current */
2030                 buf[2] = key;
2031                 buf[7] = 0xa;
2032                 buf[12] = asc;
2033                 buf[13] = ascq;
2034         }
2035 }
2036 EXPORT_SYMBOL(scsi_build_sense_buffer);