[SCSI] Handle disk devices which can not process medium access commands
[linux-3.10.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/gfp.h>
20 #include <linux/timer.h>
21 #include <linux/string.h>
22 #include <linux/kernel.h>
23 #include <linux/freezer.h>
24 #include <linux/kthread.h>
25 #include <linux/interrupt.h>
26 #include <linux/blkdev.h>
27 #include <linux/delay.h>
28
29 #include <scsi/scsi.h>
30 #include <scsi/scsi_cmnd.h>
31 #include <scsi/scsi_dbg.h>
32 #include <scsi/scsi_device.h>
33 #include <scsi/scsi_driver.h>
34 #include <scsi/scsi_eh.h>
35 #include <scsi/scsi_transport.h>
36 #include <scsi/scsi_host.h>
37 #include <scsi/scsi_ioctl.h>
38
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
41 #include "scsi_transport_api.h"
42
43 #include <trace/events/scsi.h>
44
45 #define SENSE_TIMEOUT           (10*HZ)
46
47 /*
48  * These should *probably* be handled by the host itself.
49  * Since it is allowed to sleep, it probably should.
50  */
51 #define BUS_RESET_SETTLE_TIME   (10)
52 #define HOST_RESET_SETTLE_TIME  (10)
53
54 static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
55
56 /* called with shost->host_lock held */
57 void scsi_eh_wakeup(struct Scsi_Host *shost)
58 {
59         if (shost->host_busy == shost->host_failed) {
60                 trace_scsi_eh_wakeup(shost);
61                 wake_up_process(shost->ehandler);
62                 SCSI_LOG_ERROR_RECOVERY(5,
63                                 printk("Waking error handler thread\n"));
64         }
65 }
66
67 /**
68  * scsi_schedule_eh - schedule EH for SCSI host
69  * @shost:      SCSI host to invoke error handling on.
70  *
71  * Schedule SCSI EH without scmd.
72  */
73 void scsi_schedule_eh(struct Scsi_Host *shost)
74 {
75         unsigned long flags;
76
77         spin_lock_irqsave(shost->host_lock, flags);
78
79         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
80             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
81                 shost->host_eh_scheduled++;
82                 scsi_eh_wakeup(shost);
83         }
84
85         spin_unlock_irqrestore(shost->host_lock, flags);
86 }
87 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
88
89 /**
90  * scsi_eh_scmd_add - add scsi cmd to error handling.
91  * @scmd:       scmd to run eh on.
92  * @eh_flag:    optional SCSI_EH flag.
93  *
94  * Return value:
95  *      0 on failure.
96  */
97 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
98 {
99         struct Scsi_Host *shost = scmd->device->host;
100         unsigned long flags;
101         int ret = 0;
102
103         if (!shost->ehandler)
104                 return 0;
105
106         spin_lock_irqsave(shost->host_lock, flags);
107         if (scsi_host_set_state(shost, SHOST_RECOVERY))
108                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
109                         goto out_unlock;
110
111         ret = 1;
112         scmd->eh_eflags |= eh_flag;
113         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
114         shost->host_failed++;
115         scsi_eh_wakeup(shost);
116  out_unlock:
117         spin_unlock_irqrestore(shost->host_lock, flags);
118         return ret;
119 }
120
121 /**
122  * scsi_times_out - Timeout function for normal scsi commands.
123  * @req:        request that is timing out.
124  *
125  * Notes:
126  *     We do not need to lock this.  There is the potential for a race
127  *     only in that the normal completion handling might run, but if the
128  *     normal completion function determines that the timer has already
129  *     fired, then it mustn't do anything.
130  */
131 enum blk_eh_timer_return scsi_times_out(struct request *req)
132 {
133         struct scsi_cmnd *scmd = req->special;
134         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
135         struct Scsi_Host *host = scmd->device->host;
136
137         trace_scsi_dispatch_cmd_timeout(scmd);
138         scsi_log_completion(scmd, TIMEOUT_ERROR);
139
140         if (host->transportt->eh_timed_out)
141                 rtn = host->transportt->eh_timed_out(scmd);
142         else if (host->hostt->eh_timed_out)
143                 rtn = host->hostt->eh_timed_out(scmd);
144
145         scmd->result |= DID_TIME_OUT << 16;
146
147         if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
148                      !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)))
149                 rtn = BLK_EH_HANDLED;
150
151         return rtn;
152 }
153
154 /**
155  * scsi_block_when_processing_errors - Prevent cmds from being queued.
156  * @sdev:       Device on which we are performing recovery.
157  *
158  * Description:
159  *     We block until the host is out of error recovery, and then check to
160  *     see whether the host or the device is offline.
161  *
162  * Return value:
163  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
164  */
165 int scsi_block_when_processing_errors(struct scsi_device *sdev)
166 {
167         int online;
168
169         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
170
171         online = scsi_device_online(sdev);
172
173         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
174                                           online));
175
176         return online;
177 }
178 EXPORT_SYMBOL(scsi_block_when_processing_errors);
179
180 #ifdef CONFIG_SCSI_LOGGING
181 /**
182  * scsi_eh_prt_fail_stats - Log info on failures.
183  * @shost:      scsi host being recovered.
184  * @work_q:     Queue of scsi cmds to process.
185  */
186 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
187                                           struct list_head *work_q)
188 {
189         struct scsi_cmnd *scmd;
190         struct scsi_device *sdev;
191         int total_failures = 0;
192         int cmd_failed = 0;
193         int cmd_cancel = 0;
194         int devices_failed = 0;
195
196         shost_for_each_device(sdev, shost) {
197                 list_for_each_entry(scmd, work_q, eh_entry) {
198                         if (scmd->device == sdev) {
199                                 ++total_failures;
200                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
201                                         ++cmd_cancel;
202                                 else
203                                         ++cmd_failed;
204                         }
205                 }
206
207                 if (cmd_cancel || cmd_failed) {
208                         SCSI_LOG_ERROR_RECOVERY(3,
209                                 sdev_printk(KERN_INFO, sdev,
210                                             "%s: cmds failed: %d, cancel: %d\n",
211                                             __func__, cmd_failed,
212                                             cmd_cancel));
213                         cmd_cancel = 0;
214                         cmd_failed = 0;
215                         ++devices_failed;
216                 }
217         }
218
219         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
220                                           " devices require eh work\n",
221                                    total_failures, devices_failed));
222 }
223 #endif
224
225 /**
226  * scsi_check_sense - Examine scsi cmd sense
227  * @scmd:       Cmd to have sense checked.
228  *
229  * Return value:
230  *      SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR
231  *
232  * Notes:
233  *      When a deferred error is detected the current command has
234  *      not been executed and needs retrying.
235  */
236 static int scsi_check_sense(struct scsi_cmnd *scmd)
237 {
238         struct scsi_device *sdev = scmd->device;
239         struct scsi_sense_hdr sshdr;
240
241         if (! scsi_command_normalize_sense(scmd, &sshdr))
242                 return FAILED;  /* no valid sense data */
243
244         if (scsi_sense_is_deferred(&sshdr))
245                 return NEEDS_RETRY;
246
247         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
248                         sdev->scsi_dh_data->scsi_dh->check_sense) {
249                 int rc;
250
251                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
252                 if (rc != SCSI_RETURN_NOT_HANDLED)
253                         return rc;
254                 /* handler does not care. Drop down to default handling */
255         }
256
257         /*
258          * Previous logic looked for FILEMARK, EOM or ILI which are
259          * mainly associated with tapes and returned SUCCESS.
260          */
261         if (sshdr.response_code == 0x70) {
262                 /* fixed format */
263                 if (scmd->sense_buffer[2] & 0xe0)
264                         return SUCCESS;
265         } else {
266                 /*
267                  * descriptor format: look for "stream commands sense data
268                  * descriptor" (see SSC-3). Assume single sense data
269                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
270                  */
271                 if ((sshdr.additional_length > 3) &&
272                     (scmd->sense_buffer[8] == 0x4) &&
273                     (scmd->sense_buffer[11] & 0xe0))
274                         return SUCCESS;
275         }
276
277         switch (sshdr.sense_key) {
278         case NO_SENSE:
279                 return SUCCESS;
280         case RECOVERED_ERROR:
281                 return /* soft_error */ SUCCESS;
282
283         case ABORTED_COMMAND:
284                 if (sshdr.asc == 0x10) /* DIF */
285                         return SUCCESS;
286
287                 return NEEDS_RETRY;
288         case NOT_READY:
289         case UNIT_ATTENTION:
290                 /*
291                  * if we are expecting a cc/ua because of a bus reset that we
292                  * performed, treat this just as a retry.  otherwise this is
293                  * information that we should pass up to the upper-level driver
294                  * so that we can deal with it there.
295                  */
296                 if (scmd->device->expecting_cc_ua) {
297                         /*
298                          * Because some device does not queue unit
299                          * attentions correctly, we carefully check
300                          * additional sense code and qualifier so as
301                          * not to squash media change unit attention.
302                          */
303                         if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
304                                 scmd->device->expecting_cc_ua = 0;
305                                 return NEEDS_RETRY;
306                         }
307                 }
308                 /*
309                  * if the device is in the process of becoming ready, we
310                  * should retry.
311                  */
312                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
313                         return NEEDS_RETRY;
314                 /*
315                  * if the device is not started, we need to wake
316                  * the error handler to start the motor
317                  */
318                 if (scmd->device->allow_restart &&
319                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
320                         return FAILED;
321
322                 if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
323                         scmd_printk(KERN_WARNING, scmd,
324                                     "Warning! Received an indication that the "
325                                     "LUN assignments on this target have "
326                                     "changed. The Linux SCSI layer does not "
327                                     "automatically remap LUN assignments.\n");
328                 else if (sshdr.asc == 0x3f)
329                         scmd_printk(KERN_WARNING, scmd,
330                                     "Warning! Received an indication that the "
331                                     "operating parameters on this target have "
332                                     "changed. The Linux SCSI layer does not "
333                                     "automatically adjust these parameters.\n");
334
335                 if (sshdr.asc == 0x38 && sshdr.ascq == 0x07)
336                         scmd_printk(KERN_WARNING, scmd,
337                                     "Warning! Received an indication that the "
338                                     "LUN reached a thin provisioning soft "
339                                     "threshold.\n");
340
341                 /*
342                  * Pass the UA upwards for a determination in the completion
343                  * functions.
344                  */
345                 return SUCCESS;
346
347                 /* these are not supported */
348         case COPY_ABORTED:
349         case VOLUME_OVERFLOW:
350         case MISCOMPARE:
351         case BLANK_CHECK:
352         case DATA_PROTECT:
353                 return TARGET_ERROR;
354
355         case MEDIUM_ERROR:
356                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
357                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
358                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
359                         return TARGET_ERROR;
360                 }
361                 return NEEDS_RETRY;
362
363         case HARDWARE_ERROR:
364                 if (scmd->device->retry_hwerror)
365                         return ADD_TO_MLQUEUE;
366                 else
367                         return TARGET_ERROR;
368
369         case ILLEGAL_REQUEST:
370                 if (sshdr.asc == 0x20 || /* Invalid command operation code */
371                     sshdr.asc == 0x21 || /* Logical block address out of range */
372                     sshdr.asc == 0x24 || /* Invalid field in cdb */
373                     sshdr.asc == 0x26) { /* Parameter value invalid */
374                         return TARGET_ERROR;
375                 }
376                 return SUCCESS;
377
378         default:
379                 return SUCCESS;
380         }
381 }
382
383 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
384 {
385         struct scsi_host_template *sht = sdev->host->hostt;
386         struct scsi_device *tmp_sdev;
387
388         if (!sht->change_queue_depth ||
389             sdev->queue_depth >= sdev->max_queue_depth)
390                 return;
391
392         if (time_before(jiffies,
393             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
394                 return;
395
396         if (time_before(jiffies,
397             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
398                 return;
399
400         /*
401          * Walk all devices of a target and do
402          * ramp up on them.
403          */
404         shost_for_each_device(tmp_sdev, sdev->host) {
405                 if (tmp_sdev->channel != sdev->channel ||
406                     tmp_sdev->id != sdev->id ||
407                     tmp_sdev->queue_depth == sdev->max_queue_depth)
408                         continue;
409                 /*
410                  * call back into LLD to increase queue_depth by one
411                  * with ramp up reason code.
412                  */
413                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
414                                         SCSI_QDEPTH_RAMP_UP);
415                 sdev->last_queue_ramp_up = jiffies;
416         }
417 }
418
419 static void scsi_handle_queue_full(struct scsi_device *sdev)
420 {
421         struct scsi_host_template *sht = sdev->host->hostt;
422         struct scsi_device *tmp_sdev;
423
424         if (!sht->change_queue_depth)
425                 return;
426
427         shost_for_each_device(tmp_sdev, sdev->host) {
428                 if (tmp_sdev->channel != sdev->channel ||
429                     tmp_sdev->id != sdev->id)
430                         continue;
431                 /*
432                  * We do not know the number of commands that were at
433                  * the device when we got the queue full so we start
434                  * from the highest possible value and work our way down.
435                  */
436                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
437                                         SCSI_QDEPTH_QFULL);
438         }
439 }
440
441 /**
442  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
443  * @scmd:       SCSI cmd to examine.
444  *
445  * Notes:
446  *    This is *only* called when we are examining the status of commands
447  *    queued during error recovery.  the main difference here is that we
448  *    don't allow for the possibility of retries here, and we are a lot
449  *    more restrictive about what we consider acceptable.
450  */
451 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
452 {
453         /*
454          * first check the host byte, to see if there is anything in there
455          * that would indicate what we need to do.
456          */
457         if (host_byte(scmd->result) == DID_RESET) {
458                 /*
459                  * rats.  we are already in the error handler, so we now
460                  * get to try and figure out what to do next.  if the sense
461                  * is valid, we have a pretty good idea of what to do.
462                  * if not, we mark it as FAILED.
463                  */
464                 return scsi_check_sense(scmd);
465         }
466         if (host_byte(scmd->result) != DID_OK)
467                 return FAILED;
468
469         /*
470          * next, check the message byte.
471          */
472         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
473                 return FAILED;
474
475         /*
476          * now, check the status byte to see if this indicates
477          * anything special.
478          */
479         switch (status_byte(scmd->result)) {
480         case GOOD:
481                 scsi_handle_queue_ramp_up(scmd->device);
482         case COMMAND_TERMINATED:
483                 return SUCCESS;
484         case CHECK_CONDITION:
485                 return scsi_check_sense(scmd);
486         case CONDITION_GOOD:
487         case INTERMEDIATE_GOOD:
488         case INTERMEDIATE_C_GOOD:
489                 /*
490                  * who knows?  FIXME(eric)
491                  */
492                 return SUCCESS;
493         case RESERVATION_CONFLICT:
494                 if (scmd->cmnd[0] == TEST_UNIT_READY)
495                         /* it is a success, we probed the device and
496                          * found it */
497                         return SUCCESS;
498                 /* otherwise, we failed to send the command */
499                 return FAILED;
500         case QUEUE_FULL:
501                 scsi_handle_queue_full(scmd->device);
502                 /* fall through */
503         case BUSY:
504                 return NEEDS_RETRY;
505         default:
506                 return FAILED;
507         }
508         return FAILED;
509 }
510
511 /**
512  * scsi_eh_done - Completion function for error handling.
513  * @scmd:       Cmd that is done.
514  */
515 static void scsi_eh_done(struct scsi_cmnd *scmd)
516 {
517         struct completion *eh_action;
518
519         SCSI_LOG_ERROR_RECOVERY(3,
520                 printk("%s scmd: %p result: %x\n",
521                         __func__, scmd, scmd->result));
522
523         eh_action = scmd->device->host->eh_action;
524         if (eh_action)
525                 complete(eh_action);
526 }
527
528 /**
529  * scsi_try_host_reset - ask host adapter to reset itself
530  * @scmd:       SCSI cmd to send hsot reset.
531  */
532 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
533 {
534         unsigned long flags;
535         int rtn;
536         struct Scsi_Host *host = scmd->device->host;
537         struct scsi_host_template *hostt = host->hostt;
538
539         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
540                                           __func__));
541
542         if (!hostt->eh_host_reset_handler)
543                 return FAILED;
544
545         rtn = hostt->eh_host_reset_handler(scmd);
546
547         if (rtn == SUCCESS) {
548                 if (!hostt->skip_settle_delay)
549                         ssleep(HOST_RESET_SETTLE_TIME);
550                 spin_lock_irqsave(host->host_lock, flags);
551                 scsi_report_bus_reset(host, scmd_channel(scmd));
552                 spin_unlock_irqrestore(host->host_lock, flags);
553         }
554
555         return rtn;
556 }
557
558 /**
559  * scsi_try_bus_reset - ask host to perform a bus reset
560  * @scmd:       SCSI cmd to send bus reset.
561  */
562 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
563 {
564         unsigned long flags;
565         int rtn;
566         struct Scsi_Host *host = scmd->device->host;
567         struct scsi_host_template *hostt = host->hostt;
568
569         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
570                                           __func__));
571
572         if (!hostt->eh_bus_reset_handler)
573                 return FAILED;
574
575         rtn = hostt->eh_bus_reset_handler(scmd);
576
577         if (rtn == SUCCESS) {
578                 if (!hostt->skip_settle_delay)
579                         ssleep(BUS_RESET_SETTLE_TIME);
580                 spin_lock_irqsave(host->host_lock, flags);
581                 scsi_report_bus_reset(host, scmd_channel(scmd));
582                 spin_unlock_irqrestore(host->host_lock, flags);
583         }
584
585         return rtn;
586 }
587
588 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
589 {
590         sdev->was_reset = 1;
591         sdev->expecting_cc_ua = 1;
592 }
593
594 /**
595  * scsi_try_target_reset - Ask host to perform a target reset
596  * @scmd:       SCSI cmd used to send a target reset
597  *
598  * Notes:
599  *    There is no timeout for this operation.  if this operation is
600  *    unreliable for a given host, then the host itself needs to put a
601  *    timer on it, and set the host back to a consistent state prior to
602  *    returning.
603  */
604 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
605 {
606         unsigned long flags;
607         int rtn;
608         struct Scsi_Host *host = scmd->device->host;
609         struct scsi_host_template *hostt = host->hostt;
610
611         if (!hostt->eh_target_reset_handler)
612                 return FAILED;
613
614         rtn = hostt->eh_target_reset_handler(scmd);
615         if (rtn == SUCCESS) {
616                 spin_lock_irqsave(host->host_lock, flags);
617                 __starget_for_each_device(scsi_target(scmd->device), NULL,
618                                           __scsi_report_device_reset);
619                 spin_unlock_irqrestore(host->host_lock, flags);
620         }
621
622         return rtn;
623 }
624
625 /**
626  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
627  * @scmd:       SCSI cmd used to send BDR
628  *
629  * Notes:
630  *    There is no timeout for this operation.  if this operation is
631  *    unreliable for a given host, then the host itself needs to put a
632  *    timer on it, and set the host back to a consistent state prior to
633  *    returning.
634  */
635 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
636 {
637         int rtn;
638         struct scsi_host_template *hostt = scmd->device->host->hostt;
639
640         if (!hostt->eh_device_reset_handler)
641                 return FAILED;
642
643         rtn = hostt->eh_device_reset_handler(scmd);
644         if (rtn == SUCCESS)
645                 __scsi_report_device_reset(scmd->device, NULL);
646         return rtn;
647 }
648
649 static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
650 {
651         if (!hostt->eh_abort_handler)
652                 return FAILED;
653
654         return hostt->eh_abort_handler(scmd);
655 }
656
657 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
658 {
659         if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
660                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
661                         if (scsi_try_target_reset(scmd) != SUCCESS)
662                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
663                                         scsi_try_host_reset(scmd);
664 }
665
666 /**
667  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
668  * @scmd:       SCSI command structure to hijack
669  * @ses:        structure to save restore information
670  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
671  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
672  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
673  *
674  * This function is used to save a scsi command information before re-execution
675  * as part of the error recovery process.  If @sense_bytes is 0 the command
676  * sent must be one that does not transfer any data.  If @sense_bytes != 0
677  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
678  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
679  */
680 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
681                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
682 {
683         struct scsi_device *sdev = scmd->device;
684
685         /*
686          * We need saved copies of a number of fields - this is because
687          * error handling may need to overwrite these with different values
688          * to run different commands, and once error handling is complete,
689          * we will need to restore these values prior to running the actual
690          * command.
691          */
692         ses->cmd_len = scmd->cmd_len;
693         ses->cmnd = scmd->cmnd;
694         ses->data_direction = scmd->sc_data_direction;
695         ses->sdb = scmd->sdb;
696         ses->next_rq = scmd->request->next_rq;
697         ses->result = scmd->result;
698         ses->underflow = scmd->underflow;
699         ses->prot_op = scmd->prot_op;
700
701         scmd->prot_op = SCSI_PROT_NORMAL;
702         scmd->cmnd = ses->eh_cmnd;
703         memset(scmd->cmnd, 0, BLK_MAX_CDB);
704         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
705         scmd->request->next_rq = NULL;
706
707         if (sense_bytes) {
708                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
709                                          sense_bytes);
710                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
711                             scmd->sdb.length);
712                 scmd->sdb.table.sgl = &ses->sense_sgl;
713                 scmd->sc_data_direction = DMA_FROM_DEVICE;
714                 scmd->sdb.table.nents = 1;
715                 scmd->cmnd[0] = REQUEST_SENSE;
716                 scmd->cmnd[4] = scmd->sdb.length;
717                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
718         } else {
719                 scmd->sc_data_direction = DMA_NONE;
720                 if (cmnd) {
721                         BUG_ON(cmnd_size > BLK_MAX_CDB);
722                         memcpy(scmd->cmnd, cmnd, cmnd_size);
723                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
724                 }
725         }
726
727         scmd->underflow = 0;
728
729         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
730                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
731                         (sdev->lun << 5 & 0xe0);
732
733         /*
734          * Zero the sense buffer.  The scsi spec mandates that any
735          * untransferred sense data should be interpreted as being zero.
736          */
737         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
738 }
739 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
740
741 /**
742  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
743  * @scmd:       SCSI command structure to restore
744  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
745  *
746  * Undo any damage done by above scsi_eh_prep_cmnd().
747  */
748 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
749 {
750         /*
751          * Restore original data
752          */
753         scmd->cmd_len = ses->cmd_len;
754         scmd->cmnd = ses->cmnd;
755         scmd->sc_data_direction = ses->data_direction;
756         scmd->sdb = ses->sdb;
757         scmd->request->next_rq = ses->next_rq;
758         scmd->result = ses->result;
759         scmd->underflow = ses->underflow;
760         scmd->prot_op = ses->prot_op;
761 }
762 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
763
764 /**
765  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
766  * @scmd:       SCSI command structure to hijack
767  * @cmnd:       CDB to send
768  * @cmnd_size:  size in bytes of @cmnd
769  * @timeout:    timeout for this request
770  * @sense_bytes: size of sense data to copy or 0
771  *
772  * This function is used to send a scsi command down to a target device
773  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
774  *
775  * Return value:
776  *    SUCCESS or FAILED or NEEDS_RETRY
777  */
778 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
779                              int cmnd_size, int timeout, unsigned sense_bytes)
780 {
781         struct scsi_device *sdev = scmd->device;
782         struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
783         struct Scsi_Host *shost = sdev->host;
784         DECLARE_COMPLETION_ONSTACK(done);
785         unsigned long timeleft;
786         struct scsi_eh_save ses;
787         int rtn;
788
789         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
790         shost->eh_action = &done;
791
792         scsi_log_send(scmd);
793         scmd->scsi_done = scsi_eh_done;
794         shost->hostt->queuecommand(shost, scmd);
795
796         timeleft = wait_for_completion_timeout(&done, timeout);
797
798         shost->eh_action = NULL;
799
800         scsi_log_completion(scmd, SUCCESS);
801
802         SCSI_LOG_ERROR_RECOVERY(3,
803                 printk("%s: scmd: %p, timeleft: %ld\n",
804                         __func__, scmd, timeleft));
805
806         /*
807          * If there is time left scsi_eh_done got called, and we will
808          * examine the actual status codes to see whether the command
809          * actually did complete normally, else tell the host to forget
810          * about this command.
811          */
812         if (timeleft) {
813                 rtn = scsi_eh_completed_normally(scmd);
814                 SCSI_LOG_ERROR_RECOVERY(3,
815                         printk("%s: scsi_eh_completed_normally %x\n",
816                                __func__, rtn));
817
818                 switch (rtn) {
819                 case SUCCESS:
820                 case NEEDS_RETRY:
821                 case FAILED:
822                 case TARGET_ERROR:
823                         break;
824                 case ADD_TO_MLQUEUE:
825                         rtn = NEEDS_RETRY;
826                         break;
827                 default:
828                         rtn = FAILED;
829                         break;
830                 }
831         } else {
832                 scsi_abort_eh_cmnd(scmd);
833                 rtn = FAILED;
834         }
835
836         scsi_eh_restore_cmnd(scmd, &ses);
837
838         if (sdrv->eh_action)
839                 rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
840
841         return rtn;
842 }
843
844 /**
845  * scsi_request_sense - Request sense data from a particular target.
846  * @scmd:       SCSI cmd for request sense.
847  *
848  * Notes:
849  *    Some hosts automatically obtain this information, others require
850  *    that we obtain it on our own. This function will *not* return until
851  *    the command either times out, or it completes.
852  */
853 static int scsi_request_sense(struct scsi_cmnd *scmd)
854 {
855         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
856 }
857
858 /**
859  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
860  * @scmd:       Original SCSI cmd that eh has finished.
861  * @done_q:     Queue for processed commands.
862  *
863  * Notes:
864  *    We don't want to use the normal command completion while we are are
865  *    still handling errors - it may cause other commands to be queued,
866  *    and that would disturb what we are doing.  Thus we really want to
867  *    keep a list of pending commands for final completion, and once we
868  *    are ready to leave error handling we handle completion for real.
869  */
870 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
871 {
872         scmd->device->host->host_failed--;
873         scmd->eh_eflags = 0;
874         list_move_tail(&scmd->eh_entry, done_q);
875 }
876 EXPORT_SYMBOL(scsi_eh_finish_cmd);
877
878 /**
879  * scsi_eh_get_sense - Get device sense data.
880  * @work_q:     Queue of commands to process.
881  * @done_q:     Queue of processed commands.
882  *
883  * Description:
884  *    See if we need to request sense information.  if so, then get it
885  *    now, so we have a better idea of what to do.
886  *
887  * Notes:
888  *    This has the unfortunate side effect that if a shost adapter does
889  *    not automatically request sense information, we end up shutting
890  *    it down before we request it.
891  *
892  *    All drivers should request sense information internally these days,
893  *    so for now all I have to say is tough noogies if you end up in here.
894  *
895  *    XXX: Long term this code should go away, but that needs an audit of
896  *         all LLDDs first.
897  */
898 int scsi_eh_get_sense(struct list_head *work_q,
899                       struct list_head *done_q)
900 {
901         struct scsi_cmnd *scmd, *next;
902         int rtn;
903
904         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
905                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
906                     SCSI_SENSE_VALID(scmd))
907                         continue;
908
909                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
910                                                   "%s: requesting sense\n",
911                                                   current->comm));
912                 rtn = scsi_request_sense(scmd);
913                 if (rtn != SUCCESS)
914                         continue;
915
916                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
917                                                   " result %x\n", scmd,
918                                                   scmd->result));
919                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
920
921                 rtn = scsi_decide_disposition(scmd);
922
923                 /*
924                  * if the result was normal, then just pass it along to the
925                  * upper level.
926                  */
927                 if (rtn == SUCCESS)
928                         /* we don't want this command reissued, just
929                          * finished with the sense data, so set
930                          * retries to the max allowed to ensure it
931                          * won't get reissued */
932                         scmd->retries = scmd->allowed;
933                 else if (rtn != NEEDS_RETRY)
934                         continue;
935
936                 scsi_eh_finish_cmd(scmd, done_q);
937         }
938
939         return list_empty(work_q);
940 }
941 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
942
943 /**
944  * scsi_eh_tur - Send TUR to device.
945  * @scmd:       &scsi_cmnd to send TUR
946  *
947  * Return value:
948  *    0 - Device is ready. 1 - Device NOT ready.
949  */
950 static int scsi_eh_tur(struct scsi_cmnd *scmd)
951 {
952         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
953         int retry_cnt = 1, rtn;
954
955 retry_tur:
956         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
957
958         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
959                 __func__, scmd, rtn));
960
961         switch (rtn) {
962         case NEEDS_RETRY:
963                 if (retry_cnt--)
964                         goto retry_tur;
965                 /*FALLTHRU*/
966         case SUCCESS:
967                 return 0;
968         default:
969                 return 1;
970         }
971 }
972
973 /**
974  * scsi_eh_test_devices - check if devices are responding from error recovery.
975  * @cmd_list:   scsi commands in error recovery.
976  * @work_q:     queue for commands which still need more error recovery
977  * @done_q:     queue for commands which are finished
978  * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
979  *
980  * Decription:
981  *    Tests if devices are in a working state.  Commands to devices now in
982  *    a working state are sent to the done_q while commands to devices which
983  *    are still failing to respond are returned to the work_q for more
984  *    processing.
985  **/
986 static int scsi_eh_test_devices(struct list_head *cmd_list,
987                                 struct list_head *work_q,
988                                 struct list_head *done_q, int try_stu)
989 {
990         struct scsi_cmnd *scmd, *next;
991         struct scsi_device *sdev;
992         int finish_cmds;
993
994         while (!list_empty(cmd_list)) {
995                 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
996                 sdev = scmd->device;
997
998                 finish_cmds = !scsi_device_online(scmd->device) ||
999                         (try_stu && !scsi_eh_try_stu(scmd) &&
1000                          !scsi_eh_tur(scmd)) ||
1001                         !scsi_eh_tur(scmd);
1002
1003                 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1004                         if (scmd->device == sdev) {
1005                                 if (finish_cmds)
1006                                         scsi_eh_finish_cmd(scmd, done_q);
1007                                 else
1008                                         list_move_tail(&scmd->eh_entry, work_q);
1009                         }
1010         }
1011         return list_empty(work_q);
1012 }
1013
1014
1015 /**
1016  * scsi_eh_abort_cmds - abort pending commands.
1017  * @work_q:     &list_head for pending commands.
1018  * @done_q:     &list_head for processed commands.
1019  *
1020  * Decription:
1021  *    Try and see whether or not it makes sense to try and abort the
1022  *    running command.  This only works out to be the case if we have one
1023  *    command that has timed out.  If the command simply failed, it makes
1024  *    no sense to try and abort the command, since as far as the shost
1025  *    adapter is concerned, it isn't running.
1026  */
1027 static int scsi_eh_abort_cmds(struct list_head *work_q,
1028                               struct list_head *done_q)
1029 {
1030         struct scsi_cmnd *scmd, *next;
1031         LIST_HEAD(check_list);
1032         int rtn;
1033
1034         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1035                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1036                         continue;
1037                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
1038                                                   "0x%p\n", current->comm,
1039                                                   scmd));
1040                 rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
1041                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1042                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1043                         if (rtn == FAST_IO_FAIL)
1044                                 scsi_eh_finish_cmd(scmd, done_q);
1045                         else
1046                                 list_move_tail(&scmd->eh_entry, &check_list);
1047                 } else
1048                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
1049                                                           " cmd failed:"
1050                                                           "0x%p\n",
1051                                                           current->comm,
1052                                                           scmd));
1053         }
1054
1055         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1056 }
1057
1058 /**
1059  * scsi_eh_try_stu - Send START_UNIT to device.
1060  * @scmd:       &scsi_cmnd to send START_UNIT
1061  *
1062  * Return value:
1063  *    0 - Device is ready. 1 - Device NOT ready.
1064  */
1065 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1066 {
1067         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1068
1069         if (scmd->device->allow_restart) {
1070                 int i, rtn = NEEDS_RETRY;
1071
1072                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1073                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1074
1075                 if (rtn == SUCCESS)
1076                         return 0;
1077         }
1078
1079         return 1;
1080 }
1081
1082  /**
1083  * scsi_eh_stu - send START_UNIT if needed
1084  * @shost:      &scsi host being recovered.
1085  * @work_q:     &list_head for pending commands.
1086  * @done_q:     &list_head for processed commands.
1087  *
1088  * Notes:
1089  *    If commands are failing due to not ready, initializing command required,
1090  *      try revalidating the device, which will end up sending a start unit.
1091  */
1092 static int scsi_eh_stu(struct Scsi_Host *shost,
1093                               struct list_head *work_q,
1094                               struct list_head *done_q)
1095 {
1096         struct scsi_cmnd *scmd, *stu_scmd, *next;
1097         struct scsi_device *sdev;
1098
1099         shost_for_each_device(sdev, shost) {
1100                 stu_scmd = NULL;
1101                 list_for_each_entry(scmd, work_q, eh_entry)
1102                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1103                             scsi_check_sense(scmd) == FAILED ) {
1104                                 stu_scmd = scmd;
1105                                 break;
1106                         }
1107
1108                 if (!stu_scmd)
1109                         continue;
1110
1111                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1112                                                   " 0x%p\n", current->comm, sdev));
1113
1114                 if (!scsi_eh_try_stu(stu_scmd)) {
1115                         if (!scsi_device_online(sdev) ||
1116                             !scsi_eh_tur(stu_scmd)) {
1117                                 list_for_each_entry_safe(scmd, next,
1118                                                           work_q, eh_entry) {
1119                                         if (scmd->device == sdev)
1120                                                 scsi_eh_finish_cmd(scmd, done_q);
1121                                 }
1122                         }
1123                 } else {
1124                         SCSI_LOG_ERROR_RECOVERY(3,
1125                                                 printk("%s: START_UNIT failed to sdev:"
1126                                                        " 0x%p\n", current->comm, sdev));
1127                 }
1128         }
1129
1130         return list_empty(work_q);
1131 }
1132
1133
1134 /**
1135  * scsi_eh_bus_device_reset - send bdr if needed
1136  * @shost:      scsi host being recovered.
1137  * @work_q:     &list_head for pending commands.
1138  * @done_q:     &list_head for processed commands.
1139  *
1140  * Notes:
1141  *    Try a bus device reset.  Still, look to see whether we have multiple
1142  *    devices that are jammed or not - if we have multiple devices, it
1143  *    makes no sense to try bus_device_reset - we really would need to try
1144  *    a bus_reset instead.
1145  */
1146 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1147                                     struct list_head *work_q,
1148                                     struct list_head *done_q)
1149 {
1150         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1151         struct scsi_device *sdev;
1152         int rtn;
1153
1154         shost_for_each_device(sdev, shost) {
1155                 bdr_scmd = NULL;
1156                 list_for_each_entry(scmd, work_q, eh_entry)
1157                         if (scmd->device == sdev) {
1158                                 bdr_scmd = scmd;
1159                                 break;
1160                         }
1161
1162                 if (!bdr_scmd)
1163                         continue;
1164
1165                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1166                                                   " 0x%p\n", current->comm,
1167                                                   sdev));
1168                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1169                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1170                         if (!scsi_device_online(sdev) ||
1171                             rtn == FAST_IO_FAIL ||
1172                             !scsi_eh_tur(bdr_scmd)) {
1173                                 list_for_each_entry_safe(scmd, next,
1174                                                          work_q, eh_entry) {
1175                                         if (scmd->device == sdev)
1176                                                 scsi_eh_finish_cmd(scmd,
1177                                                                    done_q);
1178                                 }
1179                         }
1180                 } else {
1181                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1182                                                           " failed sdev:"
1183                                                           "0x%p\n",
1184                                                           current->comm,
1185                                                            sdev));
1186                 }
1187         }
1188
1189         return list_empty(work_q);
1190 }
1191
1192 /**
1193  * scsi_eh_target_reset - send target reset if needed
1194  * @shost:      scsi host being recovered.
1195  * @work_q:     &list_head for pending commands.
1196  * @done_q:     &list_head for processed commands.
1197  *
1198  * Notes:
1199  *    Try a target reset.
1200  */
1201 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1202                                 struct list_head *work_q,
1203                                 struct list_head *done_q)
1204 {
1205         LIST_HEAD(tmp_list);
1206         LIST_HEAD(check_list);
1207
1208         list_splice_init(work_q, &tmp_list);
1209
1210         while (!list_empty(&tmp_list)) {
1211                 struct scsi_cmnd *next, *scmd;
1212                 int rtn;
1213                 unsigned int id;
1214
1215                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1216                 id = scmd_id(scmd);
1217
1218                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1219                                                   "to target %d\n",
1220                                                   current->comm, id));
1221                 rtn = scsi_try_target_reset(scmd);
1222                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1223                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1224                                                           " failed target: "
1225                                                           "%d\n",
1226                                                           current->comm, id));
1227                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1228                         if (scmd_id(scmd) != id)
1229                                 continue;
1230
1231                         if (rtn == SUCCESS)
1232                                 list_move_tail(&scmd->eh_entry, &check_list);
1233                         else if (rtn == FAST_IO_FAIL)
1234                                 scsi_eh_finish_cmd(scmd, done_q);
1235                         else
1236                                 /* push back on work queue for further processing */
1237                                 list_move(&scmd->eh_entry, work_q);
1238                 }
1239         }
1240
1241         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1242 }
1243
1244 /**
1245  * scsi_eh_bus_reset - send a bus reset
1246  * @shost:      &scsi host being recovered.
1247  * @work_q:     &list_head for pending commands.
1248  * @done_q:     &list_head for processed commands.
1249  */
1250 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1251                              struct list_head *work_q,
1252                              struct list_head *done_q)
1253 {
1254         struct scsi_cmnd *scmd, *chan_scmd, *next;
1255         LIST_HEAD(check_list);
1256         unsigned int channel;
1257         int rtn;
1258
1259         /*
1260          * we really want to loop over the various channels, and do this on
1261          * a channel by channel basis.  we should also check to see if any
1262          * of the failed commands are on soft_reset devices, and if so, skip
1263          * the reset.
1264          */
1265
1266         for (channel = 0; channel <= shost->max_channel; channel++) {
1267                 chan_scmd = NULL;
1268                 list_for_each_entry(scmd, work_q, eh_entry) {
1269                         if (channel == scmd_channel(scmd)) {
1270                                 chan_scmd = scmd;
1271                                 break;
1272                                 /*
1273                                  * FIXME add back in some support for
1274                                  * soft_reset devices.
1275                                  */
1276                         }
1277                 }
1278
1279                 if (!chan_scmd)
1280                         continue;
1281                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1282                                                   " %d\n", current->comm,
1283                                                   channel));
1284                 rtn = scsi_try_bus_reset(chan_scmd);
1285                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1286                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1287                                 if (channel == scmd_channel(scmd)) {
1288                                         if (rtn == FAST_IO_FAIL)
1289                                                 scsi_eh_finish_cmd(scmd,
1290                                                                    done_q);
1291                                         else
1292                                                 list_move_tail(&scmd->eh_entry,
1293                                                                &check_list);
1294                                 }
1295                         }
1296                 } else {
1297                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1298                                                           " failed chan: %d\n",
1299                                                           current->comm,
1300                                                           channel));
1301                 }
1302         }
1303         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1304 }
1305
1306 /**
1307  * scsi_eh_host_reset - send a host reset
1308  * @work_q:     list_head for processed commands.
1309  * @done_q:     list_head for processed commands.
1310  */
1311 static int scsi_eh_host_reset(struct list_head *work_q,
1312                               struct list_head *done_q)
1313 {
1314         struct scsi_cmnd *scmd, *next;
1315         LIST_HEAD(check_list);
1316         int rtn;
1317
1318         if (!list_empty(work_q)) {
1319                 scmd = list_entry(work_q->next,
1320                                   struct scsi_cmnd, eh_entry);
1321
1322                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1323                                                   , current->comm));
1324
1325                 rtn = scsi_try_host_reset(scmd);
1326                 if (rtn == SUCCESS) {
1327                         list_splice_init(work_q, &check_list);
1328                 } else if (rtn == FAST_IO_FAIL) {
1329                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1330                                         scsi_eh_finish_cmd(scmd, done_q);
1331                         }
1332                 } else {
1333                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1334                                                           " failed\n",
1335                                                           current->comm));
1336                 }
1337         }
1338         return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1339 }
1340
1341 /**
1342  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1343  * @work_q:     list_head for processed commands.
1344  * @done_q:     list_head for processed commands.
1345  */
1346 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1347                                   struct list_head *done_q)
1348 {
1349         struct scsi_cmnd *scmd, *next;
1350
1351         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1352                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1353                             "not ready after error recovery\n");
1354                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1355                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1356                         /*
1357                          * FIXME: Handle lost cmds.
1358                          */
1359                 }
1360                 scsi_eh_finish_cmd(scmd, done_q);
1361         }
1362         return;
1363 }
1364
1365 /**
1366  * scsi_noretry_cmd - determinte if command should be failed fast
1367  * @scmd:       SCSI cmd to examine.
1368  */
1369 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1370 {
1371         switch (host_byte(scmd->result)) {
1372         case DID_OK:
1373                 break;
1374         case DID_BUS_BUSY:
1375                 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1376         case DID_PARITY:
1377                 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1378         case DID_ERROR:
1379                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1380                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1381                         return 0;
1382                 /* fall through */
1383         case DID_SOFT_ERROR:
1384                 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1385         }
1386
1387         switch (status_byte(scmd->result)) {
1388         case CHECK_CONDITION:
1389                 /*
1390                  * assume caller has checked sense and determinted
1391                  * the check condition was retryable.
1392                  */
1393                 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1394                     scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1395                         return 1;
1396         }
1397
1398         return 0;
1399 }
1400
1401 /**
1402  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1403  * @scmd:       SCSI cmd to examine.
1404  *
1405  * Notes:
1406  *    This is *only* called when we are examining the status after sending
1407  *    out the actual data command.  any commands that are queued for error
1408  *    recovery (e.g. test_unit_ready) do *not* come through here.
1409  *
1410  *    When this routine returns failed, it means the error handler thread
1411  *    is woken.  In cases where the error code indicates an error that
1412  *    doesn't require the error handler read (i.e. we don't need to
1413  *    abort/reset), this function should return SUCCESS.
1414  */
1415 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1416 {
1417         int rtn;
1418
1419         /*
1420          * if the device is offline, then we clearly just pass the result back
1421          * up to the top level.
1422          */
1423         if (!scsi_device_online(scmd->device)) {
1424                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1425                                                   " as SUCCESS\n",
1426                                                   __func__));
1427                 return SUCCESS;
1428         }
1429
1430         /*
1431          * first check the host byte, to see if there is anything in there
1432          * that would indicate what we need to do.
1433          */
1434         switch (host_byte(scmd->result)) {
1435         case DID_PASSTHROUGH:
1436                 /*
1437                  * no matter what, pass this through to the upper layer.
1438                  * nuke this special code so that it looks like we are saying
1439                  * did_ok.
1440                  */
1441                 scmd->result &= 0xff00ffff;
1442                 return SUCCESS;
1443         case DID_OK:
1444                 /*
1445                  * looks good.  drop through, and check the next byte.
1446                  */
1447                 break;
1448         case DID_NO_CONNECT:
1449         case DID_BAD_TARGET:
1450         case DID_ABORT:
1451                 /*
1452                  * note - this means that we just report the status back
1453                  * to the top level driver, not that we actually think
1454                  * that it indicates SUCCESS.
1455                  */
1456                 return SUCCESS;
1457                 /*
1458                  * when the low level driver returns did_soft_error,
1459                  * it is responsible for keeping an internal retry counter
1460                  * in order to avoid endless loops (db)
1461                  *
1462                  * actually this is a bug in this function here.  we should
1463                  * be mindful of the maximum number of retries specified
1464                  * and not get stuck in a loop.
1465                  */
1466         case DID_SOFT_ERROR:
1467                 goto maybe_retry;
1468         case DID_IMM_RETRY:
1469                 return NEEDS_RETRY;
1470
1471         case DID_REQUEUE:
1472                 return ADD_TO_MLQUEUE;
1473         case DID_TRANSPORT_DISRUPTED:
1474                 /*
1475                  * LLD/transport was disrupted during processing of the IO.
1476                  * The transport class is now blocked/blocking,
1477                  * and the transport will decide what to do with the IO
1478                  * based on its timers and recovery capablilities if
1479                  * there are enough retries.
1480                  */
1481                 goto maybe_retry;
1482         case DID_TRANSPORT_FAILFAST:
1483                 /*
1484                  * The transport decided to failfast the IO (most likely
1485                  * the fast io fail tmo fired), so send IO directly upwards.
1486                  */
1487                 return SUCCESS;
1488         case DID_ERROR:
1489                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1490                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1491                         /*
1492                          * execute reservation conflict processing code
1493                          * lower down
1494                          */
1495                         break;
1496                 /* fallthrough */
1497         case DID_BUS_BUSY:
1498         case DID_PARITY:
1499                 goto maybe_retry;
1500         case DID_TIME_OUT:
1501                 /*
1502                  * when we scan the bus, we get timeout messages for
1503                  * these commands if there is no device available.
1504                  * other hosts report did_no_connect for the same thing.
1505                  */
1506                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1507                      scmd->cmnd[0] == INQUIRY)) {
1508                         return SUCCESS;
1509                 } else {
1510                         return FAILED;
1511                 }
1512         case DID_RESET:
1513                 return SUCCESS;
1514         default:
1515                 return FAILED;
1516         }
1517
1518         /*
1519          * next, check the message byte.
1520          */
1521         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1522                 return FAILED;
1523
1524         /*
1525          * check the status byte to see if this indicates anything special.
1526          */
1527         switch (status_byte(scmd->result)) {
1528         case QUEUE_FULL:
1529                 scsi_handle_queue_full(scmd->device);
1530                 /*
1531                  * the case of trying to send too many commands to a
1532                  * tagged queueing device.
1533                  */
1534         case BUSY:
1535                 /*
1536                  * device can't talk to us at the moment.  Should only
1537                  * occur (SAM-3) when the task queue is empty, so will cause
1538                  * the empty queue handling to trigger a stall in the
1539                  * device.
1540                  */
1541                 return ADD_TO_MLQUEUE;
1542         case GOOD:
1543                 scsi_handle_queue_ramp_up(scmd->device);
1544         case COMMAND_TERMINATED:
1545                 return SUCCESS;
1546         case TASK_ABORTED:
1547                 goto maybe_retry;
1548         case CHECK_CONDITION:
1549                 rtn = scsi_check_sense(scmd);
1550                 if (rtn == NEEDS_RETRY)
1551                         goto maybe_retry;
1552                 else if (rtn == TARGET_ERROR) {
1553                         /*
1554                          * Need to modify host byte to signal a
1555                          * permanent target failure
1556                          */
1557                         set_host_byte(scmd, DID_TARGET_FAILURE);
1558                         rtn = SUCCESS;
1559                 }
1560                 /* if rtn == FAILED, we have no sense information;
1561                  * returning FAILED will wake the error handler thread
1562                  * to collect the sense and redo the decide
1563                  * disposition */
1564                 return rtn;
1565         case CONDITION_GOOD:
1566         case INTERMEDIATE_GOOD:
1567         case INTERMEDIATE_C_GOOD:
1568         case ACA_ACTIVE:
1569                 /*
1570                  * who knows?  FIXME(eric)
1571                  */
1572                 return SUCCESS;
1573
1574         case RESERVATION_CONFLICT:
1575                 sdev_printk(KERN_INFO, scmd->device,
1576                             "reservation conflict\n");
1577                 set_host_byte(scmd, DID_NEXUS_FAILURE);
1578                 return SUCCESS; /* causes immediate i/o error */
1579         default:
1580                 return FAILED;
1581         }
1582         return FAILED;
1583
1584       maybe_retry:
1585
1586         /* we requeue for retry because the error was retryable, and
1587          * the request was not marked fast fail.  Note that above,
1588          * even if the request is marked fast fail, we still requeue
1589          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1590         if ((++scmd->retries) <= scmd->allowed
1591             && !scsi_noretry_cmd(scmd)) {
1592                 return NEEDS_RETRY;
1593         } else {
1594                 /*
1595                  * no more retries - report this one back to upper level.
1596                  */
1597                 return SUCCESS;
1598         }
1599 }
1600
1601 static void eh_lock_door_done(struct request *req, int uptodate)
1602 {
1603         __blk_put_request(req->q, req);
1604 }
1605
1606 /**
1607  * scsi_eh_lock_door - Prevent medium removal for the specified device
1608  * @sdev:       SCSI device to prevent medium removal
1609  *
1610  * Locking:
1611  *      We must be called from process context.
1612  *
1613  * Notes:
1614  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1615  *      head of the devices request queue, and continue.
1616  */
1617 static void scsi_eh_lock_door(struct scsi_device *sdev)
1618 {
1619         struct request *req;
1620
1621         /*
1622          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1623          * request becomes available
1624          */
1625         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1626
1627         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1628         req->cmd[1] = 0;
1629         req->cmd[2] = 0;
1630         req->cmd[3] = 0;
1631         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1632         req->cmd[5] = 0;
1633
1634         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1635
1636         req->cmd_type = REQ_TYPE_BLOCK_PC;
1637         req->cmd_flags |= REQ_QUIET;
1638         req->timeout = 10 * HZ;
1639         req->retries = 5;
1640
1641         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1642 }
1643
1644 /**
1645  * scsi_restart_operations - restart io operations to the specified host.
1646  * @shost:      Host we are restarting.
1647  *
1648  * Notes:
1649  *    When we entered the error handler, we blocked all further i/o to
1650  *    this device.  we need to 'reverse' this process.
1651  */
1652 static void scsi_restart_operations(struct Scsi_Host *shost)
1653 {
1654         struct scsi_device *sdev;
1655         unsigned long flags;
1656
1657         /*
1658          * If the door was locked, we need to insert a door lock request
1659          * onto the head of the SCSI request queue for the device.  There
1660          * is no point trying to lock the door of an off-line device.
1661          */
1662         shost_for_each_device(sdev, shost) {
1663                 if (scsi_device_online(sdev) && sdev->locked)
1664                         scsi_eh_lock_door(sdev);
1665         }
1666
1667         /*
1668          * next free up anything directly waiting upon the host.  this
1669          * will be requests for character device operations, and also for
1670          * ioctls to queued block devices.
1671          */
1672         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1673                                           __func__));
1674
1675         spin_lock_irqsave(shost->host_lock, flags);
1676         if (scsi_host_set_state(shost, SHOST_RUNNING))
1677                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1678                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1679         spin_unlock_irqrestore(shost->host_lock, flags);
1680
1681         wake_up(&shost->host_wait);
1682
1683         /*
1684          * finally we need to re-initiate requests that may be pending.  we will
1685          * have had everything blocked while error handling is taking place, and
1686          * now that error recovery is done, we will need to ensure that these
1687          * requests are started.
1688          */
1689         scsi_run_host_queues(shost);
1690 }
1691
1692 /**
1693  * scsi_eh_ready_devs - check device ready state and recover if not.
1694  * @shost:      host to be recovered.
1695  * @work_q:     &list_head for pending commands.
1696  * @done_q:     &list_head for processed commands.
1697  */
1698 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1699                         struct list_head *work_q,
1700                         struct list_head *done_q)
1701 {
1702         if (!scsi_eh_stu(shost, work_q, done_q))
1703                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1704                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1705                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1706                                         if (!scsi_eh_host_reset(work_q, done_q))
1707                                                 scsi_eh_offline_sdevs(work_q,
1708                                                                       done_q);
1709 }
1710 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1711
1712 /**
1713  * scsi_eh_flush_done_q - finish processed commands or retry them.
1714  * @done_q:     list_head of processed commands.
1715  */
1716 void scsi_eh_flush_done_q(struct list_head *done_q)
1717 {
1718         struct scsi_cmnd *scmd, *next;
1719
1720         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1721                 list_del_init(&scmd->eh_entry);
1722                 if (scsi_device_online(scmd->device) &&
1723                     !scsi_noretry_cmd(scmd) &&
1724                     (++scmd->retries <= scmd->allowed)) {
1725                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1726                                                           " retry cmd: %p\n",
1727                                                           current->comm,
1728                                                           scmd));
1729                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1730                 } else {
1731                         /*
1732                          * If just we got sense for the device (called
1733                          * scsi_eh_get_sense), scmd->result is already
1734                          * set, do not set DRIVER_TIMEOUT.
1735                          */
1736                         if (!scmd->result)
1737                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1738                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1739                                                         " cmd: %p\n",
1740                                                         current->comm, scmd));
1741                         scsi_finish_command(scmd);
1742                 }
1743         }
1744 }
1745 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1746
1747 /**
1748  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1749  * @shost:      Host to unjam.
1750  *
1751  * Notes:
1752  *    When we come in here, we *know* that all commands on the bus have
1753  *    either completed, failed or timed out.  we also know that no further
1754  *    commands are being sent to the host, so things are relatively quiet
1755  *    and we have freedom to fiddle with things as we wish.
1756  *
1757  *    This is only the *default* implementation.  it is possible for
1758  *    individual drivers to supply their own version of this function, and
1759  *    if the maintainer wishes to do this, it is strongly suggested that
1760  *    this function be taken as a template and modified.  this function
1761  *    was designed to correctly handle problems for about 95% of the
1762  *    different cases out there, and it should always provide at least a
1763  *    reasonable amount of error recovery.
1764  *
1765  *    Any command marked 'failed' or 'timeout' must eventually have
1766  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1767  *    here, so when we restart the host after we return it should have an
1768  *    empty queue.
1769  */
1770 static void scsi_unjam_host(struct Scsi_Host *shost)
1771 {
1772         unsigned long flags;
1773         LIST_HEAD(eh_work_q);
1774         LIST_HEAD(eh_done_q);
1775
1776         spin_lock_irqsave(shost->host_lock, flags);
1777         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1778         spin_unlock_irqrestore(shost->host_lock, flags);
1779
1780         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1781
1782         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1783                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1784                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1785
1786         scsi_eh_flush_done_q(&eh_done_q);
1787 }
1788
1789 /**
1790  * scsi_error_handler - SCSI error handler thread
1791  * @data:       Host for which we are running.
1792  *
1793  * Notes:
1794  *    This is the main error handling loop.  This is run as a kernel thread
1795  *    for every SCSI host and handles all error handling activity.
1796  */
1797 int scsi_error_handler(void *data)
1798 {
1799         struct Scsi_Host *shost = data;
1800
1801         /*
1802          * We use TASK_INTERRUPTIBLE so that the thread is not
1803          * counted against the load average as a running process.
1804          * We never actually get interrupted because kthread_run
1805          * disables signal delivery for the created thread.
1806          */
1807         set_current_state(TASK_INTERRUPTIBLE);
1808         while (!kthread_should_stop()) {
1809                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1810                     shost->host_failed != shost->host_busy) {
1811                         SCSI_LOG_ERROR_RECOVERY(1,
1812                                 printk("Error handler scsi_eh_%d sleeping\n",
1813                                         shost->host_no));
1814                         schedule();
1815                         set_current_state(TASK_INTERRUPTIBLE);
1816                         continue;
1817                 }
1818
1819                 __set_current_state(TASK_RUNNING);
1820                 SCSI_LOG_ERROR_RECOVERY(1,
1821                         printk("Error handler scsi_eh_%d waking up\n",
1822                                 shost->host_no));
1823
1824                 /*
1825                  * We have a host that is failing for some reason.  Figure out
1826                  * what we need to do to get it up and online again (if we can).
1827                  * If we fail, we end up taking the thing offline.
1828                  */
1829                 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
1830                         SCSI_LOG_ERROR_RECOVERY(1,
1831                                 printk(KERN_ERR "Error handler scsi_eh_%d "
1832                                                 "unable to autoresume\n",
1833                                                 shost->host_no));
1834                         continue;
1835                 }
1836
1837                 if (shost->transportt->eh_strategy_handler)
1838                         shost->transportt->eh_strategy_handler(shost);
1839                 else
1840                         scsi_unjam_host(shost);
1841
1842                 /*
1843                  * Note - if the above fails completely, the action is to take
1844                  * individual devices offline and flush the queue of any
1845                  * outstanding requests that may have been pending.  When we
1846                  * restart, we restart any I/O to any other devices on the bus
1847                  * which are still online.
1848                  */
1849                 scsi_restart_operations(shost);
1850                 if (!shost->eh_noresume)
1851                         scsi_autopm_put_host(shost);
1852                 set_current_state(TASK_INTERRUPTIBLE);
1853         }
1854         __set_current_state(TASK_RUNNING);
1855
1856         SCSI_LOG_ERROR_RECOVERY(1,
1857                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1858         shost->ehandler = NULL;
1859         return 0;
1860 }
1861
1862 /*
1863  * Function:    scsi_report_bus_reset()
1864  *
1865  * Purpose:     Utility function used by low-level drivers to report that
1866  *              they have observed a bus reset on the bus being handled.
1867  *
1868  * Arguments:   shost       - Host in question
1869  *              channel     - channel on which reset was observed.
1870  *
1871  * Returns:     Nothing
1872  *
1873  * Lock status: Host lock must be held.
1874  *
1875  * Notes:       This only needs to be called if the reset is one which
1876  *              originates from an unknown location.  Resets originated
1877  *              by the mid-level itself don't need to call this, but there
1878  *              should be no harm.
1879  *
1880  *              The main purpose of this is to make sure that a CHECK_CONDITION
1881  *              is properly treated.
1882  */
1883 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1884 {
1885         struct scsi_device *sdev;
1886
1887         __shost_for_each_device(sdev, shost) {
1888                 if (channel == sdev_channel(sdev))
1889                         __scsi_report_device_reset(sdev, NULL);
1890         }
1891 }
1892 EXPORT_SYMBOL(scsi_report_bus_reset);
1893
1894 /*
1895  * Function:    scsi_report_device_reset()
1896  *
1897  * Purpose:     Utility function used by low-level drivers to report that
1898  *              they have observed a device reset on the device being handled.
1899  *
1900  * Arguments:   shost       - Host in question
1901  *              channel     - channel on which reset was observed
1902  *              target      - target on which reset was observed
1903  *
1904  * Returns:     Nothing
1905  *
1906  * Lock status: Host lock must be held
1907  *
1908  * Notes:       This only needs to be called if the reset is one which
1909  *              originates from an unknown location.  Resets originated
1910  *              by the mid-level itself don't need to call this, but there
1911  *              should be no harm.
1912  *
1913  *              The main purpose of this is to make sure that a CHECK_CONDITION
1914  *              is properly treated.
1915  */
1916 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1917 {
1918         struct scsi_device *sdev;
1919
1920         __shost_for_each_device(sdev, shost) {
1921                 if (channel == sdev_channel(sdev) &&
1922                     target == sdev_id(sdev))
1923                         __scsi_report_device_reset(sdev, NULL);
1924         }
1925 }
1926 EXPORT_SYMBOL(scsi_report_device_reset);
1927
1928 static void
1929 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1930 {
1931 }
1932
1933 /*
1934  * Function:    scsi_reset_provider
1935  *
1936  * Purpose:     Send requested reset to a bus or device at any phase.
1937  *
1938  * Arguments:   device  - device to send reset to
1939  *              flag - reset type (see scsi.h)
1940  *
1941  * Returns:     SUCCESS/FAILURE.
1942  *
1943  * Notes:       This is used by the SCSI Generic driver to provide
1944  *              Bus/Device reset capability.
1945  */
1946 int
1947 scsi_reset_provider(struct scsi_device *dev, int flag)
1948 {
1949         struct scsi_cmnd *scmd;
1950         struct Scsi_Host *shost = dev->host;
1951         struct request req;
1952         unsigned long flags;
1953         int rtn;
1954
1955         if (scsi_autopm_get_host(shost) < 0)
1956                 return FAILED;
1957
1958         scmd = scsi_get_command(dev, GFP_KERNEL);
1959         blk_rq_init(NULL, &req);
1960         scmd->request = &req;
1961
1962         scmd->cmnd = req.cmd;
1963
1964         scmd->scsi_done         = scsi_reset_provider_done_command;
1965         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1966
1967         scmd->cmd_len                   = 0;
1968
1969         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1970
1971         spin_lock_irqsave(shost->host_lock, flags);
1972         shost->tmf_in_progress = 1;
1973         spin_unlock_irqrestore(shost->host_lock, flags);
1974
1975         switch (flag) {
1976         case SCSI_TRY_RESET_DEVICE:
1977                 rtn = scsi_try_bus_device_reset(scmd);
1978                 if (rtn == SUCCESS)
1979                         break;
1980                 /* FALLTHROUGH */
1981         case SCSI_TRY_RESET_TARGET:
1982                 rtn = scsi_try_target_reset(scmd);
1983                 if (rtn == SUCCESS)
1984                         break;
1985                 /* FALLTHROUGH */
1986         case SCSI_TRY_RESET_BUS:
1987                 rtn = scsi_try_bus_reset(scmd);
1988                 if (rtn == SUCCESS)
1989                         break;
1990                 /* FALLTHROUGH */
1991         case SCSI_TRY_RESET_HOST:
1992                 rtn = scsi_try_host_reset(scmd);
1993                 break;
1994         default:
1995                 rtn = FAILED;
1996         }
1997
1998         spin_lock_irqsave(shost->host_lock, flags);
1999         shost->tmf_in_progress = 0;
2000         spin_unlock_irqrestore(shost->host_lock, flags);
2001
2002         /*
2003          * be sure to wake up anyone who was sleeping or had their queue
2004          * suspended while we performed the TMF.
2005          */
2006         SCSI_LOG_ERROR_RECOVERY(3,
2007                 printk("%s: waking up host to restart after TMF\n",
2008                 __func__));
2009
2010         wake_up(&shost->host_wait);
2011
2012         scsi_run_host_queues(shost);
2013
2014         scsi_next_command(scmd);
2015         scsi_autopm_put_host(shost);
2016         return rtn;
2017 }
2018 EXPORT_SYMBOL(scsi_reset_provider);
2019
2020 /**
2021  * scsi_normalize_sense - normalize main elements from either fixed or
2022  *                      descriptor sense data format into a common format.
2023  *
2024  * @sense_buffer:       byte array containing sense data returned by device
2025  * @sb_len:             number of valid bytes in sense_buffer
2026  * @sshdr:              pointer to instance of structure that common
2027  *                      elements are written to.
2028  *
2029  * Notes:
2030  *      The "main elements" from sense data are: response_code, sense_key,
2031  *      asc, ascq and additional_length (only for descriptor format).
2032  *
2033  *      Typically this function can be called after a device has
2034  *      responded to a SCSI command with the CHECK_CONDITION status.
2035  *
2036  * Return value:
2037  *      1 if valid sense data information found, else 0;
2038  */
2039 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
2040                          struct scsi_sense_hdr *sshdr)
2041 {
2042         if (!sense_buffer || !sb_len)
2043                 return 0;
2044
2045         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
2046
2047         sshdr->response_code = (sense_buffer[0] & 0x7f);
2048
2049         if (!scsi_sense_valid(sshdr))
2050                 return 0;
2051
2052         if (sshdr->response_code >= 0x72) {
2053                 /*
2054                  * descriptor format
2055                  */
2056                 if (sb_len > 1)
2057                         sshdr->sense_key = (sense_buffer[1] & 0xf);
2058                 if (sb_len > 2)
2059                         sshdr->asc = sense_buffer[2];
2060                 if (sb_len > 3)
2061                         sshdr->ascq = sense_buffer[3];
2062                 if (sb_len > 7)
2063                         sshdr->additional_length = sense_buffer[7];
2064         } else {
2065                 /*
2066                  * fixed format
2067                  */
2068                 if (sb_len > 2)
2069                         sshdr->sense_key = (sense_buffer[2] & 0xf);
2070                 if (sb_len > 7) {
2071                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
2072                                          sb_len : (sense_buffer[7] + 8);
2073                         if (sb_len > 12)
2074                                 sshdr->asc = sense_buffer[12];
2075                         if (sb_len > 13)
2076                                 sshdr->ascq = sense_buffer[13];
2077                 }
2078         }
2079
2080         return 1;
2081 }
2082 EXPORT_SYMBOL(scsi_normalize_sense);
2083
2084 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
2085                                  struct scsi_sense_hdr *sshdr)
2086 {
2087         return scsi_normalize_sense(cmd->sense_buffer,
2088                         SCSI_SENSE_BUFFERSIZE, sshdr);
2089 }
2090 EXPORT_SYMBOL(scsi_command_normalize_sense);
2091
2092 /**
2093  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
2094  * @sense_buffer:       byte array of descriptor format sense data
2095  * @sb_len:             number of valid bytes in sense_buffer
2096  * @desc_type:          value of descriptor type to find
2097  *                      (e.g. 0 -> information)
2098  *
2099  * Notes:
2100  *      only valid when sense data is in descriptor format
2101  *
2102  * Return value:
2103  *      pointer to start of (first) descriptor if found else NULL
2104  */
2105 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2106                                 int desc_type)
2107 {
2108         int add_sen_len, add_len, desc_len, k;
2109         const u8 * descp;
2110
2111         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2112                 return NULL;
2113         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2114                 return NULL;
2115         add_sen_len = (add_sen_len < (sb_len - 8)) ?
2116                         add_sen_len : (sb_len - 8);
2117         descp = &sense_buffer[8];
2118         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2119                 descp += desc_len;
2120                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2121                 desc_len = add_len + 2;
2122                 if (descp[0] == desc_type)
2123                         return descp;
2124                 if (add_len < 0) // short descriptor ??
2125                         break;
2126         }
2127         return NULL;
2128 }
2129 EXPORT_SYMBOL(scsi_sense_desc_find);
2130
2131 /**
2132  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2133  * @sense_buffer:       byte array of sense data
2134  * @sb_len:             number of valid bytes in sense_buffer
2135  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2136  *                      field will be placed if found.
2137  *
2138  * Return value:
2139  *      1 if information field found, 0 if not found.
2140  */
2141 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2142                             u64 * info_out)
2143 {
2144         int j;
2145         const u8 * ucp;
2146         u64 ull;
2147
2148         if (sb_len < 7)
2149                 return 0;
2150         switch (sense_buffer[0] & 0x7f) {
2151         case 0x70:
2152         case 0x71:
2153                 if (sense_buffer[0] & 0x80) {
2154                         *info_out = (sense_buffer[3] << 24) +
2155                                     (sense_buffer[4] << 16) +
2156                                     (sense_buffer[5] << 8) + sense_buffer[6];
2157                         return 1;
2158                 } else
2159                         return 0;
2160         case 0x72:
2161         case 0x73:
2162                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2163                                            0 /* info desc */);
2164                 if (ucp && (0xa == ucp[1])) {
2165                         ull = 0;
2166                         for (j = 0; j < 8; ++j) {
2167                                 if (j > 0)
2168                                         ull <<= 8;
2169                                 ull |= ucp[4 + j];
2170                         }
2171                         *info_out = ull;
2172                         return 1;
2173                 } else
2174                         return 0;
2175         default:
2176                 return 0;
2177         }
2178 }
2179 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2180
2181 /**
2182  * scsi_build_sense_buffer - build sense data in a buffer
2183  * @desc:       Sense format (non zero == descriptor format,
2184  *              0 == fixed format)
2185  * @buf:        Where to build sense data
2186  * @key:        Sense key
2187  * @asc:        Additional sense code
2188  * @ascq:       Additional sense code qualifier
2189  *
2190  **/
2191 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2192 {
2193         if (desc) {
2194                 buf[0] = 0x72;  /* descriptor, current */
2195                 buf[1] = key;
2196                 buf[2] = asc;
2197                 buf[3] = ascq;
2198                 buf[7] = 0;
2199         } else {
2200                 buf[0] = 0x70;  /* fixed, current */
2201                 buf[2] = key;
2202                 buf[7] = 0xa;
2203                 buf[12] = asc;
2204                 buf[13] = ascq;
2205         }
2206 }
2207 EXPORT_SYMBOL(scsi_build_sense_buffer);