[SCSI] add queue_depth ramp up code
[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_times_out - Timeout function for normal scsi commands.
116  * @req:        request that is timing out.
117  *
118  * Notes:
119  *     We do not need to lock this.  There is the potential for a race
120  *     only in that the normal completion handling might run, but if the
121  *     normal completion function determines that the timer has already
122  *     fired, then it mustn't do anything.
123  */
124 enum blk_eh_timer_return scsi_times_out(struct request *req)
125 {
126         struct scsi_cmnd *scmd = req->special;
127         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
128
129         scsi_log_completion(scmd, TIMEOUT_ERROR);
130
131         if (scmd->device->host->transportt->eh_timed_out)
132                 rtn = scmd->device->host->transportt->eh_timed_out(scmd);
133         else if (scmd->device->host->hostt->eh_timed_out)
134                 rtn = scmd->device->host->hostt->eh_timed_out(scmd);
135
136         if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
137                      !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
138                 scmd->result |= DID_TIME_OUT << 16;
139                 rtn = BLK_EH_HANDLED;
140         }
141
142         return rtn;
143 }
144
145 /**
146  * scsi_block_when_processing_errors - Prevent cmds from being queued.
147  * @sdev:       Device on which we are performing recovery.
148  *
149  * Description:
150  *     We block until the host is out of error recovery, and then check to
151  *     see whether the host or the device is offline.
152  *
153  * Return value:
154  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
155  */
156 int scsi_block_when_processing_errors(struct scsi_device *sdev)
157 {
158         int online;
159
160         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
161
162         online = scsi_device_online(sdev);
163
164         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
165                                           online));
166
167         return online;
168 }
169 EXPORT_SYMBOL(scsi_block_when_processing_errors);
170
171 #ifdef CONFIG_SCSI_LOGGING
172 /**
173  * scsi_eh_prt_fail_stats - Log info on failures.
174  * @shost:      scsi host being recovered.
175  * @work_q:     Queue of scsi cmds to process.
176  */
177 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
178                                           struct list_head *work_q)
179 {
180         struct scsi_cmnd *scmd;
181         struct scsi_device *sdev;
182         int total_failures = 0;
183         int cmd_failed = 0;
184         int cmd_cancel = 0;
185         int devices_failed = 0;
186
187         shost_for_each_device(sdev, shost) {
188                 list_for_each_entry(scmd, work_q, eh_entry) {
189                         if (scmd->device == sdev) {
190                                 ++total_failures;
191                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
192                                         ++cmd_cancel;
193                                 else 
194                                         ++cmd_failed;
195                         }
196                 }
197
198                 if (cmd_cancel || cmd_failed) {
199                         SCSI_LOG_ERROR_RECOVERY(3,
200                                 sdev_printk(KERN_INFO, sdev,
201                                             "%s: cmds failed: %d, cancel: %d\n",
202                                             __func__, cmd_failed,
203                                             cmd_cancel));
204                         cmd_cancel = 0;
205                         cmd_failed = 0;
206                         ++devices_failed;
207                 }
208         }
209
210         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
211                                           " devices require eh work\n",
212                                   total_failures, devices_failed));
213 }
214 #endif
215
216 /**
217  * scsi_check_sense - Examine scsi cmd sense
218  * @scmd:       Cmd to have sense checked.
219  *
220  * Return value:
221  *      SUCCESS or FAILED or NEEDS_RETRY
222  *
223  * Notes:
224  *      When a deferred error is detected the current command has
225  *      not been executed and needs retrying.
226  */
227 static int scsi_check_sense(struct scsi_cmnd *scmd)
228 {
229         struct scsi_device *sdev = scmd->device;
230         struct scsi_sense_hdr sshdr;
231
232         if (! scsi_command_normalize_sense(scmd, &sshdr))
233                 return FAILED;  /* no valid sense data */
234
235         if (scsi_sense_is_deferred(&sshdr))
236                 return NEEDS_RETRY;
237
238         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
239                         sdev->scsi_dh_data->scsi_dh->check_sense) {
240                 int rc;
241
242                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
243                 if (rc != SCSI_RETURN_NOT_HANDLED)
244                         return rc;
245                 /* handler does not care. Drop down to default handling */
246         }
247
248         /*
249          * Previous logic looked for FILEMARK, EOM or ILI which are
250          * mainly associated with tapes and returned SUCCESS.
251          */
252         if (sshdr.response_code == 0x70) {
253                 /* fixed format */
254                 if (scmd->sense_buffer[2] & 0xe0)
255                         return SUCCESS;
256         } else {
257                 /*
258                  * descriptor format: look for "stream commands sense data
259                  * descriptor" (see SSC-3). Assume single sense data
260                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
261                  */
262                 if ((sshdr.additional_length > 3) &&
263                     (scmd->sense_buffer[8] == 0x4) &&
264                     (scmd->sense_buffer[11] & 0xe0))
265                         return SUCCESS;
266         }
267
268         switch (sshdr.sense_key) {
269         case NO_SENSE:
270                 return SUCCESS;
271         case RECOVERED_ERROR:
272                 return /* soft_error */ SUCCESS;
273
274         case ABORTED_COMMAND:
275                 if (sshdr.asc == 0x10) /* DIF */
276                         return SUCCESS;
277
278                 return NEEDS_RETRY;
279         case NOT_READY:
280         case UNIT_ATTENTION:
281                 /*
282                  * if we are expecting a cc/ua because of a bus reset that we
283                  * performed, treat this just as a retry.  otherwise this is
284                  * information that we should pass up to the upper-level driver
285                  * so that we can deal with it there.
286                  */
287                 if (scmd->device->expecting_cc_ua) {
288                         scmd->device->expecting_cc_ua = 0;
289                         return NEEDS_RETRY;
290                 }
291                 /*
292                  * if the device is in the process of becoming ready, we 
293                  * should retry.
294                  */
295                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
296                         return NEEDS_RETRY;
297                 /*
298                  * if the device is not started, we need to wake
299                  * the error handler to start the motor
300                  */
301                 if (scmd->device->allow_restart &&
302                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
303                         return FAILED;
304                 return SUCCESS;
305
306                 /* these three are not supported */
307         case COPY_ABORTED:
308         case VOLUME_OVERFLOW:
309         case MISCOMPARE:
310                 return SUCCESS;
311
312         case MEDIUM_ERROR:
313                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
314                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
315                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
316                         return SUCCESS;
317                 }
318                 return NEEDS_RETRY;
319
320         case HARDWARE_ERROR:
321                 if (scmd->device->retry_hwerror)
322                         return ADD_TO_MLQUEUE;
323                 else
324                         return SUCCESS;
325
326         case ILLEGAL_REQUEST:
327         case BLANK_CHECK:
328         case DATA_PROTECT:
329         default:
330                 return SUCCESS;
331         }
332 }
333
334 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
335 {
336         struct scsi_host_template *sht = sdev->host->hostt;
337         struct scsi_device *tmp_sdev;
338
339         if (!sht->change_queue_depth ||
340             sdev->queue_depth >= sdev->max_queue_depth)
341                 return;
342
343         if (time_before(jiffies,
344             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
345                 return;
346
347         if (time_before(jiffies,
348             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
349                 return;
350
351         /*
352          * Walk all devices of a target and do
353          * ramp up on them.
354          */
355         shost_for_each_device(tmp_sdev, sdev->host) {
356                 if (tmp_sdev->channel != sdev->channel ||
357                     tmp_sdev->id != sdev->id ||
358                     tmp_sdev->queue_depth == sdev->max_queue_depth)
359                         continue;
360                 /*
361                  * call back into LLD to increase queue_depth by one
362                  * with ramp up reason code.
363                  */
364                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
365                                         SCSI_QDEPTH_RAMP_UP);
366                 sdev->last_queue_ramp_up = jiffies;
367         }
368 }
369
370 static void scsi_handle_queue_full(struct scsi_device *sdev)
371 {
372         struct scsi_host_template *sht = sdev->host->hostt;
373         struct scsi_device *tmp_sdev;
374
375         if (!sht->change_queue_depth)
376                 return;
377
378         shost_for_each_device(tmp_sdev, sdev->host) {
379                 if (tmp_sdev->channel != sdev->channel ||
380                     tmp_sdev->id != sdev->id)
381                         continue;
382                 /*
383                  * We do not know the number of commands that were at
384                  * the device when we got the queue full so we start
385                  * from the highest possible value and work our way down.
386                  */
387                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
388                                         SCSI_QDEPTH_QFULL);
389         }
390 }
391
392 /**
393  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
394  * @scmd:       SCSI cmd to examine.
395  *
396  * Notes:
397  *    This is *only* called when we are examining the status of commands
398  *    queued during error recovery.  the main difference here is that we
399  *    don't allow for the possibility of retries here, and we are a lot
400  *    more restrictive about what we consider acceptable.
401  */
402 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
403 {
404         /*
405          * first check the host byte, to see if there is anything in there
406          * that would indicate what we need to do.
407          */
408         if (host_byte(scmd->result) == DID_RESET) {
409                 /*
410                  * rats.  we are already in the error handler, so we now
411                  * get to try and figure out what to do next.  if the sense
412                  * is valid, we have a pretty good idea of what to do.
413                  * if not, we mark it as FAILED.
414                  */
415                 return scsi_check_sense(scmd);
416         }
417         if (host_byte(scmd->result) != DID_OK)
418                 return FAILED;
419
420         /*
421          * next, check the message byte.
422          */
423         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
424                 return FAILED;
425
426         /*
427          * now, check the status byte to see if this indicates
428          * anything special.
429          */
430         switch (status_byte(scmd->result)) {
431         case GOOD:
432                 scsi_handle_queue_ramp_up(scmd->device);
433         case COMMAND_TERMINATED:
434                 return SUCCESS;
435         case CHECK_CONDITION:
436                 return scsi_check_sense(scmd);
437         case CONDITION_GOOD:
438         case INTERMEDIATE_GOOD:
439         case INTERMEDIATE_C_GOOD:
440                 /*
441                  * who knows?  FIXME(eric)
442                  */
443                 return SUCCESS;
444         case RESERVATION_CONFLICT:
445                 /*
446                  * let issuer deal with this, it could be just fine
447                  */
448                 return SUCCESS;
449         case QUEUE_FULL:
450                 scsi_handle_queue_full(scmd->device);
451                 /* fall through */
452         case BUSY:
453         default:
454                 return FAILED;
455         }
456         return FAILED;
457 }
458
459 /**
460  * scsi_eh_done - Completion function for error handling.
461  * @scmd:       Cmd that is done.
462  */
463 static void scsi_eh_done(struct scsi_cmnd *scmd)
464 {
465         struct completion     *eh_action;
466
467         SCSI_LOG_ERROR_RECOVERY(3,
468                 printk("%s scmd: %p result: %x\n",
469                         __func__, scmd, scmd->result));
470
471         eh_action = scmd->device->host->eh_action;
472         if (eh_action)
473                 complete(eh_action);
474 }
475
476 /**
477  * scsi_try_host_reset - ask host adapter to reset itself
478  * @scmd:       SCSI cmd to send hsot reset.
479  */
480 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
481 {
482         unsigned long flags;
483         int rtn;
484
485         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
486                                           __func__));
487
488         if (!scmd->device->host->hostt->eh_host_reset_handler)
489                 return FAILED;
490
491         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
492
493         if (rtn == SUCCESS) {
494                 if (!scmd->device->host->hostt->skip_settle_delay)
495                         ssleep(HOST_RESET_SETTLE_TIME);
496                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
497                 scsi_report_bus_reset(scmd->device->host,
498                                       scmd_channel(scmd));
499                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
500         }
501
502         return rtn;
503 }
504
505 /**
506  * scsi_try_bus_reset - ask host to perform a bus reset
507  * @scmd:       SCSI cmd to send bus reset.
508  */
509 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
510 {
511         unsigned long flags;
512         int rtn;
513
514         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
515                                           __func__));
516
517         if (!scmd->device->host->hostt->eh_bus_reset_handler)
518                 return FAILED;
519
520         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
521
522         if (rtn == SUCCESS) {
523                 if (!scmd->device->host->hostt->skip_settle_delay)
524                         ssleep(BUS_RESET_SETTLE_TIME);
525                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
526                 scsi_report_bus_reset(scmd->device->host,
527                                       scmd_channel(scmd));
528                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
529         }
530
531         return rtn;
532 }
533
534 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
535 {
536         sdev->was_reset = 1;
537         sdev->expecting_cc_ua = 1;
538 }
539
540 /**
541  * scsi_try_target_reset - Ask host to perform a target reset
542  * @scmd:       SCSI cmd used to send a target reset
543  *
544  * Notes:
545  *    There is no timeout for this operation.  if this operation is
546  *    unreliable for a given host, then the host itself needs to put a
547  *    timer on it, and set the host back to a consistent state prior to
548  *    returning.
549  */
550 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
551 {
552         unsigned long flags;
553         int rtn;
554
555         if (!scmd->device->host->hostt->eh_target_reset_handler)
556                 return FAILED;
557
558         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
559         if (rtn == SUCCESS) {
560                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
561                 __starget_for_each_device(scsi_target(scmd->device), NULL,
562                                           __scsi_report_device_reset);
563                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
564         }
565
566         return rtn;
567 }
568
569 /**
570  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
571  * @scmd:       SCSI cmd used to send BDR
572  *
573  * Notes:
574  *    There is no timeout for this operation.  if this operation is
575  *    unreliable for a given host, then the host itself needs to put a
576  *    timer on it, and set the host back to a consistent state prior to
577  *    returning.
578  */
579 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
580 {
581         int rtn;
582
583         if (!scmd->device->host->hostt->eh_device_reset_handler)
584                 return FAILED;
585
586         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
587         if (rtn == SUCCESS)
588                 __scsi_report_device_reset(scmd->device, NULL);
589         return rtn;
590 }
591
592 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
593 {
594         if (!scmd->device->host->hostt->eh_abort_handler)
595                 return FAILED;
596
597         return scmd->device->host->hostt->eh_abort_handler(scmd);
598 }
599
600 /**
601  * scsi_try_to_abort_cmd - Ask host to abort a running command.
602  * @scmd:       SCSI cmd to abort from Lower Level.
603  *
604  * Notes:
605  *    This function will not return until the user's completion function
606  *    has been called.  there is no timeout on this operation.  if the
607  *    author of the low-level driver wishes this operation to be timed,
608  *    they can provide this facility themselves.  helper functions in
609  *    scsi_error.c can be supplied to make this easier to do.
610  */
611 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
612 {
613         /*
614          * scsi_done was called just after the command timed out and before
615          * we had a chance to process it. (db)
616          */
617         if (scmd->serial_number == 0)
618                 return SUCCESS;
619         return __scsi_try_to_abort_cmd(scmd);
620 }
621
622 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
623 {
624         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
625                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
626                         if (scsi_try_target_reset(scmd) != SUCCESS)
627                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
628                                         scsi_try_host_reset(scmd);
629 }
630
631 /**
632  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
633  * @scmd:       SCSI command structure to hijack
634  * @ses:        structure to save restore information
635  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
636  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
637  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
638  *
639  * This function is used to save a scsi command information before re-execution
640  * as part of the error recovery process.  If @sense_bytes is 0 the command
641  * sent must be one that does not transfer any data.  If @sense_bytes != 0
642  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
643  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
644  */
645 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
646                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
647 {
648         struct scsi_device *sdev = scmd->device;
649
650         /*
651          * We need saved copies of a number of fields - this is because
652          * error handling may need to overwrite these with different values
653          * to run different commands, and once error handling is complete,
654          * we will need to restore these values prior to running the actual
655          * command.
656          */
657         ses->cmd_len = scmd->cmd_len;
658         ses->cmnd = scmd->cmnd;
659         ses->data_direction = scmd->sc_data_direction;
660         ses->sdb = scmd->sdb;
661         ses->next_rq = scmd->request->next_rq;
662         ses->result = scmd->result;
663         ses->underflow = scmd->underflow;
664         ses->prot_op = scmd->prot_op;
665
666         scmd->prot_op = SCSI_PROT_NORMAL;
667         scmd->cmnd = ses->eh_cmnd;
668         memset(scmd->cmnd, 0, BLK_MAX_CDB);
669         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
670         scmd->request->next_rq = NULL;
671
672         if (sense_bytes) {
673                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
674                                          sense_bytes);
675                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
676                             scmd->sdb.length);
677                 scmd->sdb.table.sgl = &ses->sense_sgl;
678                 scmd->sc_data_direction = DMA_FROM_DEVICE;
679                 scmd->sdb.table.nents = 1;
680                 scmd->cmnd[0] = REQUEST_SENSE;
681                 scmd->cmnd[4] = scmd->sdb.length;
682                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
683         } else {
684                 scmd->sc_data_direction = DMA_NONE;
685                 if (cmnd) {
686                         BUG_ON(cmnd_size > BLK_MAX_CDB);
687                         memcpy(scmd->cmnd, cmnd, cmnd_size);
688                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
689                 }
690         }
691
692         scmd->underflow = 0;
693
694         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
695                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
696                         (sdev->lun << 5 & 0xe0);
697
698         /*
699          * Zero the sense buffer.  The scsi spec mandates that any
700          * untransferred sense data should be interpreted as being zero.
701          */
702         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
703 }
704 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
705
706 /**
707  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
708  * @scmd:       SCSI command structure to restore
709  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
710  *
711  * Undo any damage done by above scsi_eh_prep_cmnd().
712  */
713 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
714 {
715         /*
716          * Restore original data
717          */
718         scmd->cmd_len = ses->cmd_len;
719         scmd->cmnd = ses->cmnd;
720         scmd->sc_data_direction = ses->data_direction;
721         scmd->sdb = ses->sdb;
722         scmd->request->next_rq = ses->next_rq;
723         scmd->result = ses->result;
724         scmd->underflow = ses->underflow;
725         scmd->prot_op = ses->prot_op;
726 }
727 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
728
729 /**
730  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
731  * @scmd:       SCSI command structure to hijack
732  * @cmnd:       CDB to send
733  * @cmnd_size:  size in bytes of @cmnd
734  * @timeout:    timeout for this request
735  * @sense_bytes: size of sense data to copy or 0
736  *
737  * This function is used to send a scsi command down to a target device
738  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
739  *
740  * Return value:
741  *    SUCCESS or FAILED or NEEDS_RETRY
742  */
743 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
744                              int cmnd_size, int timeout, unsigned sense_bytes)
745 {
746         struct scsi_device *sdev = scmd->device;
747         struct Scsi_Host *shost = sdev->host;
748         DECLARE_COMPLETION_ONSTACK(done);
749         unsigned long timeleft;
750         unsigned long flags;
751         struct scsi_eh_save ses;
752         int rtn;
753
754         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
755         shost->eh_action = &done;
756
757         spin_lock_irqsave(shost->host_lock, flags);
758         scsi_log_send(scmd);
759         shost->hostt->queuecommand(scmd, scsi_eh_done);
760         spin_unlock_irqrestore(shost->host_lock, flags);
761
762         timeleft = wait_for_completion_timeout(&done, timeout);
763
764         shost->eh_action = NULL;
765
766         scsi_log_completion(scmd, SUCCESS);
767
768         SCSI_LOG_ERROR_RECOVERY(3,
769                 printk("%s: scmd: %p, timeleft: %ld\n",
770                         __func__, scmd, timeleft));
771
772         /*
773          * If there is time left scsi_eh_done got called, and we will
774          * examine the actual status codes to see whether the command
775          * actually did complete normally, else tell the host to forget
776          * about this command.
777          */
778         if (timeleft) {
779                 rtn = scsi_eh_completed_normally(scmd);
780                 SCSI_LOG_ERROR_RECOVERY(3,
781                         printk("%s: scsi_eh_completed_normally %x\n",
782                                __func__, rtn));
783
784                 switch (rtn) {
785                 case SUCCESS:
786                 case NEEDS_RETRY:
787                 case FAILED:
788                         break;
789                 case ADD_TO_MLQUEUE:
790                         rtn = NEEDS_RETRY;
791                         break;
792                 default:
793                         rtn = FAILED;
794                         break;
795                 }
796         } else {
797                 scsi_abort_eh_cmnd(scmd);
798                 rtn = FAILED;
799         }
800
801         scsi_eh_restore_cmnd(scmd, &ses);
802         return rtn;
803 }
804
805 /**
806  * scsi_request_sense - Request sense data from a particular target.
807  * @scmd:       SCSI cmd for request sense.
808  *
809  * Notes:
810  *    Some hosts automatically obtain this information, others require
811  *    that we obtain it on our own. This function will *not* return until
812  *    the command either times out, or it completes.
813  */
814 static int scsi_request_sense(struct scsi_cmnd *scmd)
815 {
816         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
817 }
818
819 /**
820  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
821  * @scmd:       Original SCSI cmd that eh has finished.
822  * @done_q:     Queue for processed commands.
823  *
824  * Notes:
825  *    We don't want to use the normal command completion while we are are
826  *    still handling errors - it may cause other commands to be queued,
827  *    and that would disturb what we are doing.  Thus we really want to
828  *    keep a list of pending commands for final completion, and once we
829  *    are ready to leave error handling we handle completion for real.
830  */
831 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
832 {
833         scmd->device->host->host_failed--;
834         scmd->eh_eflags = 0;
835         list_move_tail(&scmd->eh_entry, done_q);
836 }
837 EXPORT_SYMBOL(scsi_eh_finish_cmd);
838
839 /**
840  * scsi_eh_get_sense - Get device sense data.
841  * @work_q:     Queue of commands to process.
842  * @done_q:     Queue of processed commands.
843  *
844  * Description:
845  *    See if we need to request sense information.  if so, then get it
846  *    now, so we have a better idea of what to do.  
847  *
848  * Notes:
849  *    This has the unfortunate side effect that if a shost adapter does
850  *    not automatically request sense information, we end up shutting
851  *    it down before we request it.
852  *
853  *    All drivers should request sense information internally these days,
854  *    so for now all I have to say is tough noogies if you end up in here.
855  *
856  *    XXX: Long term this code should go away, but that needs an audit of
857  *         all LLDDs first.
858  */
859 int scsi_eh_get_sense(struct list_head *work_q,
860                       struct list_head *done_q)
861 {
862         struct scsi_cmnd *scmd, *next;
863         int rtn;
864
865         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
866                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
867                     SCSI_SENSE_VALID(scmd))
868                         continue;
869
870                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
871                                                   "%s: requesting sense\n",
872                                                   current->comm));
873                 rtn = scsi_request_sense(scmd);
874                 if (rtn != SUCCESS)
875                         continue;
876
877                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
878                                                   " result %x\n", scmd,
879                                                   scmd->result));
880                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
881
882                 rtn = scsi_decide_disposition(scmd);
883
884                 /*
885                  * if the result was normal, then just pass it along to the
886                  * upper level.
887                  */
888                 if (rtn == SUCCESS)
889                         /* we don't want this command reissued, just
890                          * finished with the sense data, so set
891                          * retries to the max allowed to ensure it
892                          * won't get reissued */
893                         scmd->retries = scmd->allowed;
894                 else if (rtn != NEEDS_RETRY)
895                         continue;
896
897                 scsi_eh_finish_cmd(scmd, done_q);
898         }
899
900         return list_empty(work_q);
901 }
902 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
903
904 /**
905  * scsi_eh_tur - Send TUR to device.
906  * @scmd:       &scsi_cmnd to send TUR
907  *
908  * Return value:
909  *    0 - Device is ready. 1 - Device NOT ready.
910  */
911 static int scsi_eh_tur(struct scsi_cmnd *scmd)
912 {
913         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
914         int retry_cnt = 1, rtn;
915
916 retry_tur:
917         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
918
919         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
920                 __func__, scmd, rtn));
921
922         switch (rtn) {
923         case NEEDS_RETRY:
924                 if (retry_cnt--)
925                         goto retry_tur;
926                 /*FALLTHRU*/
927         case SUCCESS:
928                 return 0;
929         default:
930                 return 1;
931         }
932 }
933
934 /**
935  * scsi_eh_abort_cmds - abort pending commands.
936  * @work_q:     &list_head for pending commands.
937  * @done_q:     &list_head for processed commands.
938  *
939  * Decription:
940  *    Try and see whether or not it makes sense to try and abort the
941  *    running command.  This only works out to be the case if we have one
942  *    command that has timed out.  If the command simply failed, it makes
943  *    no sense to try and abort the command, since as far as the shost
944  *    adapter is concerned, it isn't running.
945  */
946 static int scsi_eh_abort_cmds(struct list_head *work_q,
947                               struct list_head *done_q)
948 {
949         struct scsi_cmnd *scmd, *next;
950         int rtn;
951
952         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
953                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
954                         continue;
955                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
956                                                   "0x%p\n", current->comm,
957                                                   scmd));
958                 rtn = scsi_try_to_abort_cmd(scmd);
959                 if (rtn == SUCCESS) {
960                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
961                         if (!scsi_device_online(scmd->device) ||
962                             !scsi_eh_tur(scmd)) {
963                                 scsi_eh_finish_cmd(scmd, done_q);
964                         }
965                                 
966                 } else
967                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
968                                                           " cmd failed:"
969                                                           "0x%p\n",
970                                                           current->comm,
971                                                           scmd));
972         }
973
974         return list_empty(work_q);
975 }
976
977 /**
978  * scsi_eh_try_stu - Send START_UNIT to device.
979  * @scmd:       &scsi_cmnd to send START_UNIT
980  *
981  * Return value:
982  *    0 - Device is ready. 1 - Device NOT ready.
983  */
984 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
985 {
986         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
987
988         if (scmd->device->allow_restart) {
989                 int i, rtn = NEEDS_RETRY;
990
991                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
992                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
993
994                 if (rtn == SUCCESS)
995                         return 0;
996         }
997
998         return 1;
999 }
1000
1001  /**
1002  * scsi_eh_stu - send START_UNIT if needed
1003  * @shost:      &scsi host being recovered.
1004  * @work_q:     &list_head for pending commands.
1005  * @done_q:     &list_head for processed commands.
1006  *
1007  * Notes:
1008  *    If commands are failing due to not ready, initializing command required,
1009  *      try revalidating the device, which will end up sending a start unit. 
1010  */
1011 static int scsi_eh_stu(struct Scsi_Host *shost,
1012                               struct list_head *work_q,
1013                               struct list_head *done_q)
1014 {
1015         struct scsi_cmnd *scmd, *stu_scmd, *next;
1016         struct scsi_device *sdev;
1017
1018         shost_for_each_device(sdev, shost) {
1019                 stu_scmd = NULL;
1020                 list_for_each_entry(scmd, work_q, eh_entry)
1021                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1022                             scsi_check_sense(scmd) == FAILED ) {
1023                                 stu_scmd = scmd;
1024                                 break;
1025                         }
1026
1027                 if (!stu_scmd)
1028                         continue;
1029
1030                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1031                                                   " 0x%p\n", current->comm, sdev));
1032
1033                 if (!scsi_eh_try_stu(stu_scmd)) {
1034                         if (!scsi_device_online(sdev) ||
1035                             !scsi_eh_tur(stu_scmd)) {
1036                                 list_for_each_entry_safe(scmd, next,
1037                                                           work_q, eh_entry) {
1038                                         if (scmd->device == sdev)
1039                                                 scsi_eh_finish_cmd(scmd, done_q);
1040                                 }
1041                         }
1042                 } else {
1043                         SCSI_LOG_ERROR_RECOVERY(3,
1044                                                 printk("%s: START_UNIT failed to sdev:"
1045                                                        " 0x%p\n", current->comm, sdev));
1046                 }
1047         }
1048
1049         return list_empty(work_q);
1050 }
1051
1052
1053 /**
1054  * scsi_eh_bus_device_reset - send bdr if needed
1055  * @shost:      scsi host being recovered.
1056  * @work_q:     &list_head for pending commands.
1057  * @done_q:     &list_head for processed commands.
1058  *
1059  * Notes:
1060  *    Try a bus device reset.  Still, look to see whether we have multiple
1061  *    devices that are jammed or not - if we have multiple devices, it
1062  *    makes no sense to try bus_device_reset - we really would need to try
1063  *    a bus_reset instead. 
1064  */
1065 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1066                                     struct list_head *work_q,
1067                                     struct list_head *done_q)
1068 {
1069         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1070         struct scsi_device *sdev;
1071         int rtn;
1072
1073         shost_for_each_device(sdev, shost) {
1074                 bdr_scmd = NULL;
1075                 list_for_each_entry(scmd, work_q, eh_entry)
1076                         if (scmd->device == sdev) {
1077                                 bdr_scmd = scmd;
1078                                 break;
1079                         }
1080
1081                 if (!bdr_scmd)
1082                         continue;
1083
1084                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1085                                                   " 0x%p\n", current->comm,
1086                                                   sdev));
1087                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1088                 if (rtn == SUCCESS) {
1089                         if (!scsi_device_online(sdev) ||
1090                             !scsi_eh_tur(bdr_scmd)) {
1091                                 list_for_each_entry_safe(scmd, next,
1092                                                          work_q, eh_entry) {
1093                                         if (scmd->device == sdev)
1094                                                 scsi_eh_finish_cmd(scmd,
1095                                                                    done_q);
1096                                 }
1097                         }
1098                 } else {
1099                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1100                                                           " failed sdev:"
1101                                                           "0x%p\n",
1102                                                           current->comm,
1103                                                            sdev));
1104                 }
1105         }
1106
1107         return list_empty(work_q);
1108 }
1109
1110 /**
1111  * scsi_eh_target_reset - send target reset if needed
1112  * @shost:      scsi host being recovered.
1113  * @work_q:     &list_head for pending commands.
1114  * @done_q:     &list_head for processed commands.
1115  *
1116  * Notes:
1117  *    Try a target reset.
1118  */
1119 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1120                                 struct list_head *work_q,
1121                                 struct list_head *done_q)
1122 {
1123         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1124         unsigned int id = 0;
1125         int rtn;
1126
1127         do {
1128                 tgtr_scmd = NULL;
1129                 list_for_each_entry(scmd, work_q, eh_entry) {
1130                         if (id == scmd_id(scmd)) {
1131                                 tgtr_scmd = scmd;
1132                                 break;
1133                         }
1134                 }
1135                 if (!tgtr_scmd) {
1136                         /* not one exactly equal; find the next highest */
1137                         list_for_each_entry(scmd, work_q, eh_entry) {
1138                                 if (scmd_id(scmd) > id &&
1139                                     (!tgtr_scmd ||
1140                                      scmd_id(tgtr_scmd) > scmd_id(scmd)))
1141                                                 tgtr_scmd = scmd;
1142                         }
1143                 }
1144                 if (!tgtr_scmd)
1145                         /* no more commands, that's it */
1146                         break;
1147
1148                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1149                                                   "to target %d\n",
1150                                                   current->comm, id));
1151                 rtn = scsi_try_target_reset(tgtr_scmd);
1152                 if (rtn == SUCCESS) {
1153                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1154                                 if (id == scmd_id(scmd))
1155                                         if (!scsi_device_online(scmd->device) ||
1156                                             !scsi_eh_tur(tgtr_scmd))
1157                                                 scsi_eh_finish_cmd(scmd,
1158                                                                    done_q);
1159                         }
1160                 } else
1161                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1162                                                           " failed target: "
1163                                                           "%d\n",
1164                                                           current->comm, id));
1165                 id++;
1166         } while(id != 0);
1167
1168         return list_empty(work_q);
1169 }
1170
1171 /**
1172  * scsi_eh_bus_reset - send a bus reset 
1173  * @shost:      &scsi host being recovered.
1174  * @work_q:     &list_head for pending commands.
1175  * @done_q:     &list_head for processed commands.
1176  */
1177 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1178                              struct list_head *work_q,
1179                              struct list_head *done_q)
1180 {
1181         struct scsi_cmnd *scmd, *chan_scmd, *next;
1182         unsigned int channel;
1183         int rtn;
1184
1185         /*
1186          * we really want to loop over the various channels, and do this on
1187          * a channel by channel basis.  we should also check to see if any
1188          * of the failed commands are on soft_reset devices, and if so, skip
1189          * the reset.  
1190          */
1191
1192         for (channel = 0; channel <= shost->max_channel; channel++) {
1193                 chan_scmd = NULL;
1194                 list_for_each_entry(scmd, work_q, eh_entry) {
1195                         if (channel == scmd_channel(scmd)) {
1196                                 chan_scmd = scmd;
1197                                 break;
1198                                 /*
1199                                  * FIXME add back in some support for
1200                                  * soft_reset devices.
1201                                  */
1202                         }
1203                 }
1204
1205                 if (!chan_scmd)
1206                         continue;
1207                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1208                                                   " %d\n", current->comm,
1209                                                   channel));
1210                 rtn = scsi_try_bus_reset(chan_scmd);
1211                 if (rtn == SUCCESS) {
1212                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1213                                 if (channel == scmd_channel(scmd))
1214                                         if (!scsi_device_online(scmd->device) ||
1215                                             !scsi_eh_tur(scmd))
1216                                                 scsi_eh_finish_cmd(scmd,
1217                                                                    done_q);
1218                         }
1219                 } else {
1220                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1221                                                           " failed chan: %d\n",
1222                                                           current->comm,
1223                                                           channel));
1224                 }
1225         }
1226         return list_empty(work_q);
1227 }
1228
1229 /**
1230  * scsi_eh_host_reset - send a host reset 
1231  * @work_q:     list_head for processed commands.
1232  * @done_q:     list_head for processed commands.
1233  */
1234 static int scsi_eh_host_reset(struct list_head *work_q,
1235                               struct list_head *done_q)
1236 {
1237         struct scsi_cmnd *scmd, *next;
1238         int rtn;
1239
1240         if (!list_empty(work_q)) {
1241                 scmd = list_entry(work_q->next,
1242                                   struct scsi_cmnd, eh_entry);
1243
1244                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1245                                                   , current->comm));
1246
1247                 rtn = scsi_try_host_reset(scmd);
1248                 if (rtn == SUCCESS) {
1249                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1250                                 if (!scsi_device_online(scmd->device) ||
1251                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1252                                     !scsi_eh_tur(scmd))
1253                                         scsi_eh_finish_cmd(scmd, done_q);
1254                         }
1255                 } else {
1256                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1257                                                           " failed\n",
1258                                                           current->comm));
1259                 }
1260         }
1261         return list_empty(work_q);
1262 }
1263
1264 /**
1265  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1266  * @work_q:     list_head for processed commands.
1267  * @done_q:     list_head for processed commands.
1268  */
1269 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1270                                   struct list_head *done_q)
1271 {
1272         struct scsi_cmnd *scmd, *next;
1273
1274         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1275                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1276                             "not ready after error recovery\n");
1277                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1278                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1279                         /*
1280                          * FIXME: Handle lost cmds.
1281                          */
1282                 }
1283                 scsi_eh_finish_cmd(scmd, done_q);
1284         }
1285         return;
1286 }
1287
1288 /**
1289  * scsi_noretry_cmd - determinte if command should be failed fast
1290  * @scmd:       SCSI cmd to examine.
1291  */
1292 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1293 {
1294         switch (host_byte(scmd->result)) {
1295         case DID_OK:
1296                 break;
1297         case DID_BUS_BUSY:
1298                 return blk_failfast_transport(scmd->request);
1299         case DID_PARITY:
1300                 return blk_failfast_dev(scmd->request);
1301         case DID_ERROR:
1302                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1303                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1304                         return 0;
1305                 /* fall through */
1306         case DID_SOFT_ERROR:
1307                 return blk_failfast_driver(scmd->request);
1308         }
1309
1310         switch (status_byte(scmd->result)) {
1311         case CHECK_CONDITION:
1312                 /*
1313                  * assume caller has checked sense and determinted
1314                  * the check condition was retryable.
1315                  */
1316                 return blk_failfast_dev(scmd->request);
1317         }
1318
1319         return 0;
1320 }
1321
1322 /**
1323  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1324  * @scmd:       SCSI cmd to examine.
1325  *
1326  * Notes:
1327  *    This is *only* called when we are examining the status after sending
1328  *    out the actual data command.  any commands that are queued for error
1329  *    recovery (e.g. test_unit_ready) do *not* come through here.
1330  *
1331  *    When this routine returns failed, it means the error handler thread
1332  *    is woken.  In cases where the error code indicates an error that
1333  *    doesn't require the error handler read (i.e. we don't need to
1334  *    abort/reset), this function should return SUCCESS.
1335  */
1336 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1337 {
1338         int rtn;
1339
1340         /*
1341          * if the device is offline, then we clearly just pass the result back
1342          * up to the top level.
1343          */
1344         if (!scsi_device_online(scmd->device)) {
1345                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1346                                                   " as SUCCESS\n",
1347                                                   __func__));
1348                 return SUCCESS;
1349         }
1350
1351         /*
1352          * first check the host byte, to see if there is anything in there
1353          * that would indicate what we need to do.
1354          */
1355         switch (host_byte(scmd->result)) {
1356         case DID_PASSTHROUGH:
1357                 /*
1358                  * no matter what, pass this through to the upper layer.
1359                  * nuke this special code so that it looks like we are saying
1360                  * did_ok.
1361                  */
1362                 scmd->result &= 0xff00ffff;
1363                 return SUCCESS;
1364         case DID_OK:
1365                 /*
1366                  * looks good.  drop through, and check the next byte.
1367                  */
1368                 break;
1369         case DID_NO_CONNECT:
1370         case DID_BAD_TARGET:
1371         case DID_ABORT:
1372                 /*
1373                  * note - this means that we just report the status back
1374                  * to the top level driver, not that we actually think
1375                  * that it indicates SUCCESS.
1376                  */
1377                 return SUCCESS;
1378                 /*
1379                  * when the low level driver returns did_soft_error,
1380                  * it is responsible for keeping an internal retry counter 
1381                  * in order to avoid endless loops (db)
1382                  *
1383                  * actually this is a bug in this function here.  we should
1384                  * be mindful of the maximum number of retries specified
1385                  * and not get stuck in a loop.
1386                  */
1387         case DID_SOFT_ERROR:
1388                 goto maybe_retry;
1389         case DID_IMM_RETRY:
1390                 return NEEDS_RETRY;
1391
1392         case DID_REQUEUE:
1393                 return ADD_TO_MLQUEUE;
1394         case DID_TRANSPORT_DISRUPTED:
1395                 /*
1396                  * LLD/transport was disrupted during processing of the IO.
1397                  * The transport class is now blocked/blocking,
1398                  * and the transport will decide what to do with the IO
1399                  * based on its timers and recovery capablilities if
1400                  * there are enough retries.
1401                  */
1402                 goto maybe_retry;
1403         case DID_TRANSPORT_FAILFAST:
1404                 /*
1405                  * The transport decided to failfast the IO (most likely
1406                  * the fast io fail tmo fired), so send IO directly upwards.
1407                  */
1408                 return SUCCESS;
1409         case DID_ERROR:
1410                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1411                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1412                         /*
1413                          * execute reservation conflict processing code
1414                          * lower down
1415                          */
1416                         break;
1417                 /* fallthrough */
1418
1419         case DID_BUS_BUSY:
1420         case DID_PARITY:
1421                 goto maybe_retry;
1422         case DID_TIME_OUT:
1423                 /*
1424                  * when we scan the bus, we get timeout messages for
1425                  * these commands if there is no device available.
1426                  * other hosts report did_no_connect for the same thing.
1427                  */
1428                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1429                      scmd->cmnd[0] == INQUIRY)) {
1430                         return SUCCESS;
1431                 } else {
1432                         return FAILED;
1433                 }
1434         case DID_RESET:
1435                 return SUCCESS;
1436         default:
1437                 return FAILED;
1438         }
1439
1440         /*
1441          * next, check the message byte.
1442          */
1443         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1444                 return FAILED;
1445
1446         /*
1447          * check the status byte to see if this indicates anything special.
1448          */
1449         switch (status_byte(scmd->result)) {
1450         case QUEUE_FULL:
1451                 scsi_handle_queue_full(scmd->device);
1452                 /*
1453                  * the case of trying to send too many commands to a
1454                  * tagged queueing device.
1455                  */
1456         case BUSY:
1457                 /*
1458                  * device can't talk to us at the moment.  Should only
1459                  * occur (SAM-3) when the task queue is empty, so will cause
1460                  * the empty queue handling to trigger a stall in the
1461                  * device.
1462                  */
1463                 return ADD_TO_MLQUEUE;
1464         case GOOD:
1465                 scsi_handle_queue_ramp_up(scmd->device);
1466         case COMMAND_TERMINATED:
1467                 return SUCCESS;
1468         case TASK_ABORTED:
1469                 goto maybe_retry;
1470         case CHECK_CONDITION:
1471                 rtn = scsi_check_sense(scmd);
1472                 if (rtn == NEEDS_RETRY)
1473                         goto maybe_retry;
1474                 /* if rtn == FAILED, we have no sense information;
1475                  * returning FAILED will wake the error handler thread
1476                  * to collect the sense and redo the decide
1477                  * disposition */
1478                 return rtn;
1479         case CONDITION_GOOD:
1480         case INTERMEDIATE_GOOD:
1481         case INTERMEDIATE_C_GOOD:
1482         case ACA_ACTIVE:
1483                 /*
1484                  * who knows?  FIXME(eric)
1485                  */
1486                 return SUCCESS;
1487
1488         case RESERVATION_CONFLICT:
1489                 sdev_printk(KERN_INFO, scmd->device,
1490                             "reservation conflict\n");
1491                 return SUCCESS; /* causes immediate i/o error */
1492         default:
1493                 return FAILED;
1494         }
1495         return FAILED;
1496
1497       maybe_retry:
1498
1499         /* we requeue for retry because the error was retryable, and
1500          * the request was not marked fast fail.  Note that above,
1501          * even if the request is marked fast fail, we still requeue
1502          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1503         if ((++scmd->retries) <= scmd->allowed
1504             && !scsi_noretry_cmd(scmd)) {
1505                 return NEEDS_RETRY;
1506         } else {
1507                 /*
1508                  * no more retries - report this one back to upper level.
1509                  */
1510                 return SUCCESS;
1511         }
1512 }
1513
1514 static void eh_lock_door_done(struct request *req, int uptodate)
1515 {
1516         __blk_put_request(req->q, req);
1517 }
1518
1519 /**
1520  * scsi_eh_lock_door - Prevent medium removal for the specified device
1521  * @sdev:       SCSI device to prevent medium removal
1522  *
1523  * Locking:
1524  *      We must be called from process context.
1525  *
1526  * Notes:
1527  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1528  *      head of the devices request queue, and continue.
1529  */
1530 static void scsi_eh_lock_door(struct scsi_device *sdev)
1531 {
1532         struct request *req;
1533
1534         /*
1535          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1536          * request becomes available
1537          */
1538         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1539
1540         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1541         req->cmd[1] = 0;
1542         req->cmd[2] = 0;
1543         req->cmd[3] = 0;
1544         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1545         req->cmd[5] = 0;
1546
1547         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1548
1549         req->cmd_type = REQ_TYPE_BLOCK_PC;
1550         req->cmd_flags |= REQ_QUIET;
1551         req->timeout = 10 * HZ;
1552         req->retries = 5;
1553
1554         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1555 }
1556
1557 /**
1558  * scsi_restart_operations - restart io operations to the specified host.
1559  * @shost:      Host we are restarting.
1560  *
1561  * Notes:
1562  *    When we entered the error handler, we blocked all further i/o to
1563  *    this device.  we need to 'reverse' this process.
1564  */
1565 static void scsi_restart_operations(struct Scsi_Host *shost)
1566 {
1567         struct scsi_device *sdev;
1568         unsigned long flags;
1569
1570         /*
1571          * If the door was locked, we need to insert a door lock request
1572          * onto the head of the SCSI request queue for the device.  There
1573          * is no point trying to lock the door of an off-line device.
1574          */
1575         shost_for_each_device(sdev, shost) {
1576                 if (scsi_device_online(sdev) && sdev->locked)
1577                         scsi_eh_lock_door(sdev);
1578         }
1579
1580         /*
1581          * next free up anything directly waiting upon the host.  this
1582          * will be requests for character device operations, and also for
1583          * ioctls to queued block devices.
1584          */
1585         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1586                                           __func__));
1587
1588         spin_lock_irqsave(shost->host_lock, flags);
1589         if (scsi_host_set_state(shost, SHOST_RUNNING))
1590                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1591                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1592         spin_unlock_irqrestore(shost->host_lock, flags);
1593
1594         wake_up(&shost->host_wait);
1595
1596         /*
1597          * finally we need to re-initiate requests that may be pending.  we will
1598          * have had everything blocked while error handling is taking place, and
1599          * now that error recovery is done, we will need to ensure that these
1600          * requests are started.
1601          */
1602         scsi_run_host_queues(shost);
1603 }
1604
1605 /**
1606  * scsi_eh_ready_devs - check device ready state and recover if not.
1607  * @shost:      host to be recovered.
1608  * @work_q:     &list_head for pending commands.
1609  * @done_q:     &list_head for processed commands.
1610  */
1611 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1612                         struct list_head *work_q,
1613                         struct list_head *done_q)
1614 {
1615         if (!scsi_eh_stu(shost, work_q, done_q))
1616                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1617                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1618                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1619                                         if (!scsi_eh_host_reset(work_q, done_q))
1620                                                 scsi_eh_offline_sdevs(work_q,
1621                                                                       done_q);
1622 }
1623 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1624
1625 /**
1626  * scsi_eh_flush_done_q - finish processed commands or retry them.
1627  * @done_q:     list_head of processed commands.
1628  */
1629 void scsi_eh_flush_done_q(struct list_head *done_q)
1630 {
1631         struct scsi_cmnd *scmd, *next;
1632
1633         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1634                 list_del_init(&scmd->eh_entry);
1635                 if (scsi_device_online(scmd->device) &&
1636                     !scsi_noretry_cmd(scmd) &&
1637                     (++scmd->retries <= scmd->allowed)) {
1638                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1639                                                           " retry cmd: %p\n",
1640                                                           current->comm,
1641                                                           scmd));
1642                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1643                 } else {
1644                         /*
1645                          * If just we got sense for the device (called
1646                          * scsi_eh_get_sense), scmd->result is already
1647                          * set, do not set DRIVER_TIMEOUT.
1648                          */
1649                         if (!scmd->result)
1650                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1651                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1652                                                         " cmd: %p\n",
1653                                                         current->comm, scmd));
1654                         scsi_finish_command(scmd);
1655                 }
1656         }
1657 }
1658 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1659
1660 /**
1661  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1662  * @shost:      Host to unjam.
1663  *
1664  * Notes:
1665  *    When we come in here, we *know* that all commands on the bus have
1666  *    either completed, failed or timed out.  we also know that no further
1667  *    commands are being sent to the host, so things are relatively quiet
1668  *    and we have freedom to fiddle with things as we wish.
1669  *
1670  *    This is only the *default* implementation.  it is possible for
1671  *    individual drivers to supply their own version of this function, and
1672  *    if the maintainer wishes to do this, it is strongly suggested that
1673  *    this function be taken as a template and modified.  this function
1674  *    was designed to correctly handle problems for about 95% of the
1675  *    different cases out there, and it should always provide at least a
1676  *    reasonable amount of error recovery.
1677  *
1678  *    Any command marked 'failed' or 'timeout' must eventually have
1679  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1680  *    here, so when we restart the host after we return it should have an
1681  *    empty queue.
1682  */
1683 static void scsi_unjam_host(struct Scsi_Host *shost)
1684 {
1685         unsigned long flags;
1686         LIST_HEAD(eh_work_q);
1687         LIST_HEAD(eh_done_q);
1688
1689         spin_lock_irqsave(shost->host_lock, flags);
1690         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1691         spin_unlock_irqrestore(shost->host_lock, flags);
1692
1693         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1694
1695         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1696                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1697                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1698
1699         scsi_eh_flush_done_q(&eh_done_q);
1700 }
1701
1702 /**
1703  * scsi_error_handler - SCSI error handler thread
1704  * @data:       Host for which we are running.
1705  *
1706  * Notes:
1707  *    This is the main error handling loop.  This is run as a kernel thread
1708  *    for every SCSI host and handles all error handling activity.
1709  */
1710 int scsi_error_handler(void *data)
1711 {
1712         struct Scsi_Host *shost = data;
1713
1714         /*
1715          * We use TASK_INTERRUPTIBLE so that the thread is not
1716          * counted against the load average as a running process.
1717          * We never actually get interrupted because kthread_run
1718          * disables signal delivery for the created thread.
1719          */
1720         set_current_state(TASK_INTERRUPTIBLE);
1721         while (!kthread_should_stop()) {
1722                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1723                     shost->host_failed != shost->host_busy) {
1724                         SCSI_LOG_ERROR_RECOVERY(1,
1725                                 printk("Error handler scsi_eh_%d sleeping\n",
1726                                         shost->host_no));
1727                         schedule();
1728                         set_current_state(TASK_INTERRUPTIBLE);
1729                         continue;
1730                 }
1731
1732                 __set_current_state(TASK_RUNNING);
1733                 SCSI_LOG_ERROR_RECOVERY(1,
1734                         printk("Error handler scsi_eh_%d waking up\n",
1735                                 shost->host_no));
1736
1737                 /*
1738                  * We have a host that is failing for some reason.  Figure out
1739                  * what we need to do to get it up and online again (if we can).
1740                  * If we fail, we end up taking the thing offline.
1741                  */
1742                 if (shost->transportt->eh_strategy_handler)
1743                         shost->transportt->eh_strategy_handler(shost);
1744                 else
1745                         scsi_unjam_host(shost);
1746
1747                 /*
1748                  * Note - if the above fails completely, the action is to take
1749                  * individual devices offline and flush the queue of any
1750                  * outstanding requests that may have been pending.  When we
1751                  * restart, we restart any I/O to any other devices on the bus
1752                  * which are still online.
1753                  */
1754                 scsi_restart_operations(shost);
1755                 set_current_state(TASK_INTERRUPTIBLE);
1756         }
1757         __set_current_state(TASK_RUNNING);
1758
1759         SCSI_LOG_ERROR_RECOVERY(1,
1760                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1761         shost->ehandler = NULL;
1762         return 0;
1763 }
1764
1765 /*
1766  * Function:    scsi_report_bus_reset()
1767  *
1768  * Purpose:     Utility function used by low-level drivers to report that
1769  *              they have observed a bus reset on the bus being handled.
1770  *
1771  * Arguments:   shost       - Host in question
1772  *              channel     - channel on which reset was observed.
1773  *
1774  * Returns:     Nothing
1775  *
1776  * Lock status: Host lock must be held.
1777  *
1778  * Notes:       This only needs to be called if the reset is one which
1779  *              originates from an unknown location.  Resets originated
1780  *              by the mid-level itself don't need to call this, but there
1781  *              should be no harm.
1782  *
1783  *              The main purpose of this is to make sure that a CHECK_CONDITION
1784  *              is properly treated.
1785  */
1786 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1787 {
1788         struct scsi_device *sdev;
1789
1790         __shost_for_each_device(sdev, shost) {
1791                 if (channel == sdev_channel(sdev))
1792                         __scsi_report_device_reset(sdev, NULL);
1793         }
1794 }
1795 EXPORT_SYMBOL(scsi_report_bus_reset);
1796
1797 /*
1798  * Function:    scsi_report_device_reset()
1799  *
1800  * Purpose:     Utility function used by low-level drivers to report that
1801  *              they have observed a device reset on the device being handled.
1802  *
1803  * Arguments:   shost       - Host in question
1804  *              channel     - channel on which reset was observed
1805  *              target      - target on which reset was observed
1806  *
1807  * Returns:     Nothing
1808  *
1809  * Lock status: Host lock must be held
1810  *
1811  * Notes:       This only needs to be called if the reset is one which
1812  *              originates from an unknown location.  Resets originated
1813  *              by the mid-level itself don't need to call this, but there
1814  *              should be no harm.
1815  *
1816  *              The main purpose of this is to make sure that a CHECK_CONDITION
1817  *              is properly treated.
1818  */
1819 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1820 {
1821         struct scsi_device *sdev;
1822
1823         __shost_for_each_device(sdev, shost) {
1824                 if (channel == sdev_channel(sdev) &&
1825                     target == sdev_id(sdev))
1826                         __scsi_report_device_reset(sdev, NULL);
1827         }
1828 }
1829 EXPORT_SYMBOL(scsi_report_device_reset);
1830
1831 static void
1832 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1833 {
1834 }
1835
1836 /*
1837  * Function:    scsi_reset_provider
1838  *
1839  * Purpose:     Send requested reset to a bus or device at any phase.
1840  *
1841  * Arguments:   device  - device to send reset to
1842  *              flag - reset type (see scsi.h)
1843  *
1844  * Returns:     SUCCESS/FAILURE.
1845  *
1846  * Notes:       This is used by the SCSI Generic driver to provide
1847  *              Bus/Device reset capability.
1848  */
1849 int
1850 scsi_reset_provider(struct scsi_device *dev, int flag)
1851 {
1852         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1853         struct Scsi_Host *shost = dev->host;
1854         struct request req;
1855         unsigned long flags;
1856         int rtn;
1857
1858         blk_rq_init(NULL, &req);
1859         scmd->request = &req;
1860
1861         scmd->cmnd = req.cmd;
1862
1863         scmd->scsi_done         = scsi_reset_provider_done_command;
1864         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1865
1866         scmd->cmd_len                   = 0;
1867
1868         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1869
1870         spin_lock_irqsave(shost->host_lock, flags);
1871         shost->tmf_in_progress = 1;
1872         spin_unlock_irqrestore(shost->host_lock, flags);
1873
1874         switch (flag) {
1875         case SCSI_TRY_RESET_DEVICE:
1876                 rtn = scsi_try_bus_device_reset(scmd);
1877                 if (rtn == SUCCESS)
1878                         break;
1879                 /* FALLTHROUGH */
1880         case SCSI_TRY_RESET_TARGET:
1881                 rtn = scsi_try_target_reset(scmd);
1882                 if (rtn == SUCCESS)
1883                         break;
1884                 /* FALLTHROUGH */
1885         case SCSI_TRY_RESET_BUS:
1886                 rtn = scsi_try_bus_reset(scmd);
1887                 if (rtn == SUCCESS)
1888                         break;
1889                 /* FALLTHROUGH */
1890         case SCSI_TRY_RESET_HOST:
1891                 rtn = scsi_try_host_reset(scmd);
1892                 break;
1893         default:
1894                 rtn = FAILED;
1895         }
1896
1897         spin_lock_irqsave(shost->host_lock, flags);
1898         shost->tmf_in_progress = 0;
1899         spin_unlock_irqrestore(shost->host_lock, flags);
1900
1901         /*
1902          * be sure to wake up anyone who was sleeping or had their queue
1903          * suspended while we performed the TMF.
1904          */
1905         SCSI_LOG_ERROR_RECOVERY(3,
1906                 printk("%s: waking up host to restart after TMF\n",
1907                 __func__));
1908
1909         wake_up(&shost->host_wait);
1910
1911         scsi_run_host_queues(shost);
1912
1913         scsi_next_command(scmd);
1914         return rtn;
1915 }
1916 EXPORT_SYMBOL(scsi_reset_provider);
1917
1918 /**
1919  * scsi_normalize_sense - normalize main elements from either fixed or
1920  *                      descriptor sense data format into a common format.
1921  *
1922  * @sense_buffer:       byte array containing sense data returned by device
1923  * @sb_len:             number of valid bytes in sense_buffer
1924  * @sshdr:              pointer to instance of structure that common
1925  *                      elements are written to.
1926  *
1927  * Notes:
1928  *      The "main elements" from sense data are: response_code, sense_key,
1929  *      asc, ascq and additional_length (only for descriptor format).
1930  *
1931  *      Typically this function can be called after a device has
1932  *      responded to a SCSI command with the CHECK_CONDITION status.
1933  *
1934  * Return value:
1935  *      1 if valid sense data information found, else 0;
1936  */
1937 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1938                          struct scsi_sense_hdr *sshdr)
1939 {
1940         if (!sense_buffer || !sb_len)
1941                 return 0;
1942
1943         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1944
1945         sshdr->response_code = (sense_buffer[0] & 0x7f);
1946
1947         if (!scsi_sense_valid(sshdr))
1948                 return 0;
1949
1950         if (sshdr->response_code >= 0x72) {
1951                 /*
1952                  * descriptor format
1953                  */
1954                 if (sb_len > 1)
1955                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1956                 if (sb_len > 2)
1957                         sshdr->asc = sense_buffer[2];
1958                 if (sb_len > 3)
1959                         sshdr->ascq = sense_buffer[3];
1960                 if (sb_len > 7)
1961                         sshdr->additional_length = sense_buffer[7];
1962         } else {
1963                 /* 
1964                  * fixed format
1965                  */
1966                 if (sb_len > 2)
1967                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1968                 if (sb_len > 7) {
1969                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1970                                          sb_len : (sense_buffer[7] + 8);
1971                         if (sb_len > 12)
1972                                 sshdr->asc = sense_buffer[12];
1973                         if (sb_len > 13)
1974                                 sshdr->ascq = sense_buffer[13];
1975                 }
1976         }
1977
1978         return 1;
1979 }
1980 EXPORT_SYMBOL(scsi_normalize_sense);
1981
1982 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1983                                  struct scsi_sense_hdr *sshdr)
1984 {
1985         return scsi_normalize_sense(cmd->sense_buffer,
1986                         SCSI_SENSE_BUFFERSIZE, sshdr);
1987 }
1988 EXPORT_SYMBOL(scsi_command_normalize_sense);
1989
1990 /**
1991  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1992  * @sense_buffer:       byte array of descriptor format sense data
1993  * @sb_len:             number of valid bytes in sense_buffer
1994  * @desc_type:          value of descriptor type to find
1995  *                      (e.g. 0 -> information)
1996  *
1997  * Notes:
1998  *      only valid when sense data is in descriptor format
1999  *
2000  * Return value:
2001  *      pointer to start of (first) descriptor if found else NULL
2002  */
2003 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2004                                 int desc_type)
2005 {
2006         int add_sen_len, add_len, desc_len, k;
2007         const u8 * descp;
2008
2009         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2010                 return NULL;
2011         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2012                 return NULL;
2013         add_sen_len = (add_sen_len < (sb_len - 8)) ?
2014                         add_sen_len : (sb_len - 8);
2015         descp = &sense_buffer[8];
2016         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2017                 descp += desc_len;
2018                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2019                 desc_len = add_len + 2;
2020                 if (descp[0] == desc_type)
2021                         return descp;
2022                 if (add_len < 0) // short descriptor ??
2023                         break;
2024         }
2025         return NULL;
2026 }
2027 EXPORT_SYMBOL(scsi_sense_desc_find);
2028
2029 /**
2030  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2031  * @sense_buffer:       byte array of sense data
2032  * @sb_len:             number of valid bytes in sense_buffer
2033  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2034  *                      field will be placed if found.
2035  *
2036  * Return value:
2037  *      1 if information field found, 0 if not found.
2038  */
2039 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2040                             u64 * info_out)
2041 {
2042         int j;
2043         const u8 * ucp;
2044         u64 ull;
2045
2046         if (sb_len < 7)
2047                 return 0;
2048         switch (sense_buffer[0] & 0x7f) {
2049         case 0x70:
2050         case 0x71:
2051                 if (sense_buffer[0] & 0x80) {
2052                         *info_out = (sense_buffer[3] << 24) +
2053                                     (sense_buffer[4] << 16) +
2054                                     (sense_buffer[5] << 8) + sense_buffer[6];
2055                         return 1;
2056                 } else
2057                         return 0;
2058         case 0x72:
2059         case 0x73:
2060                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2061                                            0 /* info desc */);
2062                 if (ucp && (0xa == ucp[1])) {
2063                         ull = 0;
2064                         for (j = 0; j < 8; ++j) {
2065                                 if (j > 0)
2066                                         ull <<= 8;
2067                                 ull |= ucp[4 + j];
2068                         }
2069                         *info_out = ull;
2070                         return 1;
2071                 } else
2072                         return 0;
2073         default:
2074                 return 0;
2075         }
2076 }
2077 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2078
2079 /**
2080  * scsi_build_sense_buffer - build sense data in a buffer
2081  * @desc:       Sense format (non zero == descriptor format,
2082  *              0 == fixed format)
2083  * @buf:        Where to build sense data
2084  * @key:        Sense key
2085  * @asc:        Additional sense code
2086  * @ascq:       Additional sense code qualifier
2087  *
2088  **/
2089 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2090 {
2091         if (desc) {
2092                 buf[0] = 0x72;  /* descriptor, current */
2093                 buf[1] = key;
2094                 buf[2] = asc;
2095                 buf[3] = ascq;
2096                 buf[7] = 0;
2097         } else {
2098                 buf[0] = 0x70;  /* fixed, current */
2099                 buf[2] = key;
2100                 buf[7] = 0xa;
2101                 buf[12] = asc;
2102                 buf[13] = ascq;
2103         }
2104 }
2105 EXPORT_SYMBOL(scsi_build_sense_buffer);