[SCSI] bnx2fc: Broadcom FCoE offload driver
[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/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_eh.h>
34 #include <scsi/scsi_transport.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi_ioctl.h>
37
38 #include "scsi_priv.h"
39 #include "scsi_logging.h"
40 #include "scsi_transport_api.h"
41
42 #include <trace/events/scsi.h>
43
44 #define SENSE_TIMEOUT           (10*HZ)
45
46 /*
47  * These should *probably* be handled by the host itself.
48  * Since it is allowed to sleep, it probably should.
49  */
50 #define BUS_RESET_SETTLE_TIME   (10)
51 #define HOST_RESET_SETTLE_TIME  (10)
52
53 /* called with shost->host_lock held */
54 void scsi_eh_wakeup(struct Scsi_Host *shost)
55 {
56         if (shost->host_busy == shost->host_failed) {
57                 trace_scsi_eh_wakeup(shost);
58                 wake_up_process(shost->ehandler);
59                 SCSI_LOG_ERROR_RECOVERY(5,
60                                 printk("Waking error handler thread\n"));
61         }
62 }
63
64 /**
65  * scsi_schedule_eh - schedule EH for SCSI host
66  * @shost:      SCSI host to invoke error handling on.
67  *
68  * Schedule SCSI EH without scmd.
69  */
70 void scsi_schedule_eh(struct Scsi_Host *shost)
71 {
72         unsigned long flags;
73
74         spin_lock_irqsave(shost->host_lock, flags);
75
76         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
77             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
78                 shost->host_eh_scheduled++;
79                 scsi_eh_wakeup(shost);
80         }
81
82         spin_unlock_irqrestore(shost->host_lock, flags);
83 }
84 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
85
86 /**
87  * scsi_eh_scmd_add - add scsi cmd to error handling.
88  * @scmd:       scmd to run eh on.
89  * @eh_flag:    optional SCSI_EH flag.
90  *
91  * Return value:
92  *      0 on failure.
93  */
94 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
95 {
96         struct Scsi_Host *shost = scmd->device->host;
97         unsigned long flags;
98         int ret = 0;
99
100         if (!shost->ehandler)
101                 return 0;
102
103         spin_lock_irqsave(shost->host_lock, flags);
104         if (scsi_host_set_state(shost, SHOST_RECOVERY))
105                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
106                         goto out_unlock;
107
108         ret = 1;
109         scmd->eh_eflags |= eh_flag;
110         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
111         shost->host_failed++;
112         scsi_eh_wakeup(shost);
113  out_unlock:
114         spin_unlock_irqrestore(shost->host_lock, flags);
115         return ret;
116 }
117
118 /**
119  * scsi_times_out - Timeout function for normal scsi commands.
120  * @req:        request that is timing out.
121  *
122  * Notes:
123  *     We do not need to lock this.  There is the potential for a race
124  *     only in that the normal completion handling might run, but if the
125  *     normal completion function determines that the timer has already
126  *     fired, then it mustn't do anything.
127  */
128 enum blk_eh_timer_return scsi_times_out(struct request *req)
129 {
130         struct scsi_cmnd *scmd = req->special;
131         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
132
133         trace_scsi_dispatch_cmd_timeout(scmd);
134         scsi_log_completion(scmd, TIMEOUT_ERROR);
135
136         if (scmd->device->host->transportt->eh_timed_out)
137                 rtn = scmd->device->host->transportt->eh_timed_out(scmd);
138         else if (scmd->device->host->hostt->eh_timed_out)
139                 rtn = scmd->device->host->hostt->eh_timed_out(scmd);
140
141         if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
142                      !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
143                 scmd->result |= DID_TIME_OUT << 16;
144                 rtn = BLK_EH_HANDLED;
145         }
146
147         return rtn;
148 }
149
150 /**
151  * scsi_block_when_processing_errors - Prevent cmds from being queued.
152  * @sdev:       Device on which we are performing recovery.
153  *
154  * Description:
155  *     We block until the host is out of error recovery, and then check to
156  *     see whether the host or the device is offline.
157  *
158  * Return value:
159  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
160  */
161 int scsi_block_when_processing_errors(struct scsi_device *sdev)
162 {
163         int online;
164
165         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
166
167         online = scsi_device_online(sdev);
168
169         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
170                                           online));
171
172         return online;
173 }
174 EXPORT_SYMBOL(scsi_block_when_processing_errors);
175
176 #ifdef CONFIG_SCSI_LOGGING
177 /**
178  * scsi_eh_prt_fail_stats - Log info on failures.
179  * @shost:      scsi host being recovered.
180  * @work_q:     Queue of scsi cmds to process.
181  */
182 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
183                                           struct list_head *work_q)
184 {
185         struct scsi_cmnd *scmd;
186         struct scsi_device *sdev;
187         int total_failures = 0;
188         int cmd_failed = 0;
189         int cmd_cancel = 0;
190         int devices_failed = 0;
191
192         shost_for_each_device(sdev, shost) {
193                 list_for_each_entry(scmd, work_q, eh_entry) {
194                         if (scmd->device == sdev) {
195                                 ++total_failures;
196                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
197                                         ++cmd_cancel;
198                                 else 
199                                         ++cmd_failed;
200                         }
201                 }
202
203                 if (cmd_cancel || cmd_failed) {
204                         SCSI_LOG_ERROR_RECOVERY(3,
205                                 sdev_printk(KERN_INFO, sdev,
206                                             "%s: cmds failed: %d, cancel: %d\n",
207                                             __func__, cmd_failed,
208                                             cmd_cancel));
209                         cmd_cancel = 0;
210                         cmd_failed = 0;
211                         ++devices_failed;
212                 }
213         }
214
215         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
216                                           " devices require eh work\n",
217                                   total_failures, devices_failed));
218 }
219 #endif
220
221 /**
222  * scsi_check_sense - Examine scsi cmd sense
223  * @scmd:       Cmd to have sense checked.
224  *
225  * Return value:
226  *      SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR
227  *
228  * Notes:
229  *      When a deferred error is detected the current command has
230  *      not been executed and needs retrying.
231  */
232 static int scsi_check_sense(struct scsi_cmnd *scmd)
233 {
234         struct scsi_device *sdev = scmd->device;
235         struct scsi_sense_hdr sshdr;
236
237         if (! scsi_command_normalize_sense(scmd, &sshdr))
238                 return FAILED;  /* no valid sense data */
239
240         if (scsi_sense_is_deferred(&sshdr))
241                 return NEEDS_RETRY;
242
243         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
244                         sdev->scsi_dh_data->scsi_dh->check_sense) {
245                 int rc;
246
247                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
248                 if (rc != SCSI_RETURN_NOT_HANDLED)
249                         return rc;
250                 /* handler does not care. Drop down to default handling */
251         }
252
253         /*
254          * Previous logic looked for FILEMARK, EOM or ILI which are
255          * mainly associated with tapes and returned SUCCESS.
256          */
257         if (sshdr.response_code == 0x70) {
258                 /* fixed format */
259                 if (scmd->sense_buffer[2] & 0xe0)
260                         return SUCCESS;
261         } else {
262                 /*
263                  * descriptor format: look for "stream commands sense data
264                  * descriptor" (see SSC-3). Assume single sense data
265                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
266                  */
267                 if ((sshdr.additional_length > 3) &&
268                     (scmd->sense_buffer[8] == 0x4) &&
269                     (scmd->sense_buffer[11] & 0xe0))
270                         return SUCCESS;
271         }
272
273         switch (sshdr.sense_key) {
274         case NO_SENSE:
275                 return SUCCESS;
276         case RECOVERED_ERROR:
277                 return /* soft_error */ SUCCESS;
278
279         case ABORTED_COMMAND:
280                 if (sshdr.asc == 0x10) /* DIF */
281                         return SUCCESS;
282
283                 return NEEDS_RETRY;
284         case NOT_READY:
285         case UNIT_ATTENTION:
286                 /*
287                  * if we are expecting a cc/ua because of a bus reset that we
288                  * performed, treat this just as a retry.  otherwise this is
289                  * information that we should pass up to the upper-level driver
290                  * so that we can deal with it there.
291                  */
292                 if (scmd->device->expecting_cc_ua) {
293                         scmd->device->expecting_cc_ua = 0;
294                         return NEEDS_RETRY;
295                 }
296                 /*
297                  * if the device is in the process of becoming ready, we 
298                  * should retry.
299                  */
300                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
301                         return NEEDS_RETRY;
302                 /*
303                  * if the device is not started, we need to wake
304                  * the error handler to start the motor
305                  */
306                 if (scmd->device->allow_restart &&
307                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
308                         return FAILED;
309
310                 if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
311                         scmd_printk(KERN_WARNING, scmd,
312                                     "Warning! Received an indication that the "
313                                     "LUN assignments on this target have "
314                                     "changed. The Linux SCSI layer does not "
315                                     "automatically remap LUN assignments.\n");
316                 else if (sshdr.asc == 0x3f)
317                         scmd_printk(KERN_WARNING, scmd,
318                                     "Warning! Received an indication that the "
319                                     "operating parameters on this target have "
320                                     "changed. The Linux SCSI layer does not "
321                                     "automatically adjust these parameters.\n");
322
323                 /*
324                  * Pass the UA upwards for a determination in the completion
325                  * functions.
326                  */
327                 return SUCCESS;
328
329                 /* these are not supported */
330         case COPY_ABORTED:
331         case VOLUME_OVERFLOW:
332         case MISCOMPARE:
333         case BLANK_CHECK:
334         case DATA_PROTECT:
335                 return TARGET_ERROR;
336
337         case MEDIUM_ERROR:
338                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
339                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
340                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
341                         return TARGET_ERROR;
342                 }
343                 return NEEDS_RETRY;
344
345         case HARDWARE_ERROR:
346                 if (scmd->device->retry_hwerror)
347                         return ADD_TO_MLQUEUE;
348                 else
349                         return TARGET_ERROR;
350
351         case ILLEGAL_REQUEST:
352         default:
353                 return SUCCESS;
354         }
355 }
356
357 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
358 {
359         struct scsi_host_template *sht = sdev->host->hostt;
360         struct scsi_device *tmp_sdev;
361
362         if (!sht->change_queue_depth ||
363             sdev->queue_depth >= sdev->max_queue_depth)
364                 return;
365
366         if (time_before(jiffies,
367             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
368                 return;
369
370         if (time_before(jiffies,
371             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
372                 return;
373
374         /*
375          * Walk all devices of a target and do
376          * ramp up on them.
377          */
378         shost_for_each_device(tmp_sdev, sdev->host) {
379                 if (tmp_sdev->channel != sdev->channel ||
380                     tmp_sdev->id != sdev->id ||
381                     tmp_sdev->queue_depth == sdev->max_queue_depth)
382                         continue;
383                 /*
384                  * call back into LLD to increase queue_depth by one
385                  * with ramp up reason code.
386                  */
387                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
388                                         SCSI_QDEPTH_RAMP_UP);
389                 sdev->last_queue_ramp_up = jiffies;
390         }
391 }
392
393 static void scsi_handle_queue_full(struct scsi_device *sdev)
394 {
395         struct scsi_host_template *sht = sdev->host->hostt;
396         struct scsi_device *tmp_sdev;
397
398         if (!sht->change_queue_depth)
399                 return;
400
401         shost_for_each_device(tmp_sdev, sdev->host) {
402                 if (tmp_sdev->channel != sdev->channel ||
403                     tmp_sdev->id != sdev->id)
404                         continue;
405                 /*
406                  * We do not know the number of commands that were at
407                  * the device when we got the queue full so we start
408                  * from the highest possible value and work our way down.
409                  */
410                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
411                                         SCSI_QDEPTH_QFULL);
412         }
413 }
414
415 /**
416  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
417  * @scmd:       SCSI cmd to examine.
418  *
419  * Notes:
420  *    This is *only* called when we are examining the status of commands
421  *    queued during error recovery.  the main difference here is that we
422  *    don't allow for the possibility of retries here, and we are a lot
423  *    more restrictive about what we consider acceptable.
424  */
425 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
426 {
427         /*
428          * first check the host byte, to see if there is anything in there
429          * that would indicate what we need to do.
430          */
431         if (host_byte(scmd->result) == DID_RESET) {
432                 /*
433                  * rats.  we are already in the error handler, so we now
434                  * get to try and figure out what to do next.  if the sense
435                  * is valid, we have a pretty good idea of what to do.
436                  * if not, we mark it as FAILED.
437                  */
438                 return scsi_check_sense(scmd);
439         }
440         if (host_byte(scmd->result) != DID_OK)
441                 return FAILED;
442
443         /*
444          * next, check the message byte.
445          */
446         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
447                 return FAILED;
448
449         /*
450          * now, check the status byte to see if this indicates
451          * anything special.
452          */
453         switch (status_byte(scmd->result)) {
454         case GOOD:
455                 scsi_handle_queue_ramp_up(scmd->device);
456         case COMMAND_TERMINATED:
457                 return SUCCESS;
458         case CHECK_CONDITION:
459                 return scsi_check_sense(scmd);
460         case CONDITION_GOOD:
461         case INTERMEDIATE_GOOD:
462         case INTERMEDIATE_C_GOOD:
463                 /*
464                  * who knows?  FIXME(eric)
465                  */
466                 return SUCCESS;
467         case RESERVATION_CONFLICT:
468                 if (scmd->cmnd[0] == TEST_UNIT_READY)
469                         /* it is a success, we probed the device and
470                          * found it */
471                         return SUCCESS;
472                 /* otherwise, we failed to send the command */
473                 return FAILED;
474         case QUEUE_FULL:
475                 scsi_handle_queue_full(scmd->device);
476                 /* fall through */
477         case BUSY:
478                 return NEEDS_RETRY;
479         default:
480                 return FAILED;
481         }
482         return FAILED;
483 }
484
485 /**
486  * scsi_eh_done - Completion function for error handling.
487  * @scmd:       Cmd that is done.
488  */
489 static void scsi_eh_done(struct scsi_cmnd *scmd)
490 {
491         struct completion     *eh_action;
492
493         SCSI_LOG_ERROR_RECOVERY(3,
494                 printk("%s scmd: %p result: %x\n",
495                         __func__, scmd, scmd->result));
496
497         eh_action = scmd->device->host->eh_action;
498         if (eh_action)
499                 complete(eh_action);
500 }
501
502 /**
503  * scsi_try_host_reset - ask host adapter to reset itself
504  * @scmd:       SCSI cmd to send hsot reset.
505  */
506 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
507 {
508         unsigned long flags;
509         int rtn;
510
511         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
512                                           __func__));
513
514         if (!scmd->device->host->hostt->eh_host_reset_handler)
515                 return FAILED;
516
517         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
518
519         if (rtn == SUCCESS) {
520                 if (!scmd->device->host->hostt->skip_settle_delay)
521                         ssleep(HOST_RESET_SETTLE_TIME);
522                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
523                 scsi_report_bus_reset(scmd->device->host,
524                                       scmd_channel(scmd));
525                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
526         }
527
528         return rtn;
529 }
530
531 /**
532  * scsi_try_bus_reset - ask host to perform a bus reset
533  * @scmd:       SCSI cmd to send bus reset.
534  */
535 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
536 {
537         unsigned long flags;
538         int rtn;
539
540         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
541                                           __func__));
542
543         if (!scmd->device->host->hostt->eh_bus_reset_handler)
544                 return FAILED;
545
546         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
547
548         if (rtn == SUCCESS) {
549                 if (!scmd->device->host->hostt->skip_settle_delay)
550                         ssleep(BUS_RESET_SETTLE_TIME);
551                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
552                 scsi_report_bus_reset(scmd->device->host,
553                                       scmd_channel(scmd));
554                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
555         }
556
557         return rtn;
558 }
559
560 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
561 {
562         sdev->was_reset = 1;
563         sdev->expecting_cc_ua = 1;
564 }
565
566 /**
567  * scsi_try_target_reset - Ask host to perform a target reset
568  * @scmd:       SCSI cmd used to send a target reset
569  *
570  * Notes:
571  *    There is no timeout for this operation.  if this operation is
572  *    unreliable for a given host, then the host itself needs to put a
573  *    timer on it, and set the host back to a consistent state prior to
574  *    returning.
575  */
576 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
577 {
578         unsigned long flags;
579         int rtn;
580
581         if (!scmd->device->host->hostt->eh_target_reset_handler)
582                 return FAILED;
583
584         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
585         if (rtn == SUCCESS) {
586                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
587                 __starget_for_each_device(scsi_target(scmd->device), NULL,
588                                           __scsi_report_device_reset);
589                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
590         }
591
592         return rtn;
593 }
594
595 /**
596  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
597  * @scmd:       SCSI cmd used to send BDR
598  *
599  * Notes:
600  *    There is no timeout for this operation.  if this operation is
601  *    unreliable for a given host, then the host itself needs to put a
602  *    timer on it, and set the host back to a consistent state prior to
603  *    returning.
604  */
605 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
606 {
607         int rtn;
608
609         if (!scmd->device->host->hostt->eh_device_reset_handler)
610                 return FAILED;
611
612         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
613         if (rtn == SUCCESS)
614                 __scsi_report_device_reset(scmd->device, NULL);
615         return rtn;
616 }
617
618 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
619 {
620         if (!scmd->device->host->hostt->eh_abort_handler)
621                 return FAILED;
622
623         return scmd->device->host->hostt->eh_abort_handler(scmd);
624 }
625
626 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
627 {
628         if (scsi_try_to_abort_cmd(scmd) != SUCCESS)
629                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
630                         if (scsi_try_target_reset(scmd) != SUCCESS)
631                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
632                                         scsi_try_host_reset(scmd);
633 }
634
635 /**
636  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
637  * @scmd:       SCSI command structure to hijack
638  * @ses:        structure to save restore information
639  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
640  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
641  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
642  *
643  * This function is used to save a scsi command information before re-execution
644  * as part of the error recovery process.  If @sense_bytes is 0 the command
645  * sent must be one that does not transfer any data.  If @sense_bytes != 0
646  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
647  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
648  */
649 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
650                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
651 {
652         struct scsi_device *sdev = scmd->device;
653
654         /*
655          * We need saved copies of a number of fields - this is because
656          * error handling may need to overwrite these with different values
657          * to run different commands, and once error handling is complete,
658          * we will need to restore these values prior to running the actual
659          * command.
660          */
661         ses->cmd_len = scmd->cmd_len;
662         ses->cmnd = scmd->cmnd;
663         ses->data_direction = scmd->sc_data_direction;
664         ses->sdb = scmd->sdb;
665         ses->next_rq = scmd->request->next_rq;
666         ses->result = scmd->result;
667         ses->underflow = scmd->underflow;
668         ses->prot_op = scmd->prot_op;
669
670         scmd->prot_op = SCSI_PROT_NORMAL;
671         scmd->cmnd = ses->eh_cmnd;
672         memset(scmd->cmnd, 0, BLK_MAX_CDB);
673         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
674         scmd->request->next_rq = NULL;
675
676         if (sense_bytes) {
677                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
678                                          sense_bytes);
679                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
680                             scmd->sdb.length);
681                 scmd->sdb.table.sgl = &ses->sense_sgl;
682                 scmd->sc_data_direction = DMA_FROM_DEVICE;
683                 scmd->sdb.table.nents = 1;
684                 scmd->cmnd[0] = REQUEST_SENSE;
685                 scmd->cmnd[4] = scmd->sdb.length;
686                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
687         } else {
688                 scmd->sc_data_direction = DMA_NONE;
689                 if (cmnd) {
690                         BUG_ON(cmnd_size > BLK_MAX_CDB);
691                         memcpy(scmd->cmnd, cmnd, cmnd_size);
692                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
693                 }
694         }
695
696         scmd->underflow = 0;
697
698         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
699                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
700                         (sdev->lun << 5 & 0xe0);
701
702         /*
703          * Zero the sense buffer.  The scsi spec mandates that any
704          * untransferred sense data should be interpreted as being zero.
705          */
706         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
707 }
708 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
709
710 /**
711  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
712  * @scmd:       SCSI command structure to restore
713  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
714  *
715  * Undo any damage done by above scsi_eh_prep_cmnd().
716  */
717 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
718 {
719         /*
720          * Restore original data
721          */
722         scmd->cmd_len = ses->cmd_len;
723         scmd->cmnd = ses->cmnd;
724         scmd->sc_data_direction = ses->data_direction;
725         scmd->sdb = ses->sdb;
726         scmd->request->next_rq = ses->next_rq;
727         scmd->result = ses->result;
728         scmd->underflow = ses->underflow;
729         scmd->prot_op = ses->prot_op;
730 }
731 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
732
733 /**
734  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
735  * @scmd:       SCSI command structure to hijack
736  * @cmnd:       CDB to send
737  * @cmnd_size:  size in bytes of @cmnd
738  * @timeout:    timeout for this request
739  * @sense_bytes: size of sense data to copy or 0
740  *
741  * This function is used to send a scsi command down to a target device
742  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
743  *
744  * Return value:
745  *    SUCCESS or FAILED or NEEDS_RETRY
746  */
747 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
748                              int cmnd_size, int timeout, unsigned sense_bytes)
749 {
750         struct scsi_device *sdev = scmd->device;
751         struct Scsi_Host *shost = sdev->host;
752         DECLARE_COMPLETION_ONSTACK(done);
753         unsigned long timeleft;
754         struct scsi_eh_save ses;
755         int rtn;
756
757         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
758         shost->eh_action = &done;
759
760         scsi_log_send(scmd);
761         scmd->scsi_done = scsi_eh_done;
762         shost->hostt->queuecommand(shost, scmd);
763
764         timeleft = wait_for_completion_timeout(&done, timeout);
765
766         shost->eh_action = NULL;
767
768         scsi_log_completion(scmd, SUCCESS);
769
770         SCSI_LOG_ERROR_RECOVERY(3,
771                 printk("%s: scmd: %p, timeleft: %ld\n",
772                         __func__, scmd, timeleft));
773
774         /*
775          * If there is time left scsi_eh_done got called, and we will
776          * examine the actual status codes to see whether the command
777          * actually did complete normally, else tell the host to forget
778          * about this command.
779          */
780         if (timeleft) {
781                 rtn = scsi_eh_completed_normally(scmd);
782                 SCSI_LOG_ERROR_RECOVERY(3,
783                         printk("%s: scsi_eh_completed_normally %x\n",
784                                __func__, rtn));
785
786                 switch (rtn) {
787                 case SUCCESS:
788                 case NEEDS_RETRY:
789                 case FAILED:
790                 case TARGET_ERROR:
791                         break;
792                 case ADD_TO_MLQUEUE:
793                         rtn = NEEDS_RETRY;
794                         break;
795                 default:
796                         rtn = FAILED;
797                         break;
798                 }
799         } else {
800                 scsi_abort_eh_cmnd(scmd);
801                 rtn = FAILED;
802         }
803
804         scsi_eh_restore_cmnd(scmd, &ses);
805         return rtn;
806 }
807
808 /**
809  * scsi_request_sense - Request sense data from a particular target.
810  * @scmd:       SCSI cmd for request sense.
811  *
812  * Notes:
813  *    Some hosts automatically obtain this information, others require
814  *    that we obtain it on our own. This function will *not* return until
815  *    the command either times out, or it completes.
816  */
817 static int scsi_request_sense(struct scsi_cmnd *scmd)
818 {
819         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
820 }
821
822 /**
823  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
824  * @scmd:       Original SCSI cmd that eh has finished.
825  * @done_q:     Queue for processed commands.
826  *
827  * Notes:
828  *    We don't want to use the normal command completion while we are are
829  *    still handling errors - it may cause other commands to be queued,
830  *    and that would disturb what we are doing.  Thus we really want to
831  *    keep a list of pending commands for final completion, and once we
832  *    are ready to leave error handling we handle completion for real.
833  */
834 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
835 {
836         scmd->device->host->host_failed--;
837         scmd->eh_eflags = 0;
838         list_move_tail(&scmd->eh_entry, done_q);
839 }
840 EXPORT_SYMBOL(scsi_eh_finish_cmd);
841
842 /**
843  * scsi_eh_get_sense - Get device sense data.
844  * @work_q:     Queue of commands to process.
845  * @done_q:     Queue of processed commands.
846  *
847  * Description:
848  *    See if we need to request sense information.  if so, then get it
849  *    now, so we have a better idea of what to do.  
850  *
851  * Notes:
852  *    This has the unfortunate side effect that if a shost adapter does
853  *    not automatically request sense information, we end up shutting
854  *    it down before we request it.
855  *
856  *    All drivers should request sense information internally these days,
857  *    so for now all I have to say is tough noogies if you end up in here.
858  *
859  *    XXX: Long term this code should go away, but that needs an audit of
860  *         all LLDDs first.
861  */
862 int scsi_eh_get_sense(struct list_head *work_q,
863                       struct list_head *done_q)
864 {
865         struct scsi_cmnd *scmd, *next;
866         int rtn;
867
868         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
869                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
870                     SCSI_SENSE_VALID(scmd))
871                         continue;
872
873                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
874                                                   "%s: requesting sense\n",
875                                                   current->comm));
876                 rtn = scsi_request_sense(scmd);
877                 if (rtn != SUCCESS)
878                         continue;
879
880                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
881                                                   " result %x\n", scmd,
882                                                   scmd->result));
883                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
884
885                 rtn = scsi_decide_disposition(scmd);
886
887                 /*
888                  * if the result was normal, then just pass it along to the
889                  * upper level.
890                  */
891                 if (rtn == SUCCESS)
892                         /* we don't want this command reissued, just
893                          * finished with the sense data, so set
894                          * retries to the max allowed to ensure it
895                          * won't get reissued */
896                         scmd->retries = scmd->allowed;
897                 else if (rtn != NEEDS_RETRY)
898                         continue;
899
900                 scsi_eh_finish_cmd(scmd, done_q);
901         }
902
903         return list_empty(work_q);
904 }
905 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
906
907 /**
908  * scsi_eh_tur - Send TUR to device.
909  * @scmd:       &scsi_cmnd to send TUR
910  *
911  * Return value:
912  *    0 - Device is ready. 1 - Device NOT ready.
913  */
914 static int scsi_eh_tur(struct scsi_cmnd *scmd)
915 {
916         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
917         int retry_cnt = 1, rtn;
918
919 retry_tur:
920         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
921
922         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
923                 __func__, scmd, rtn));
924
925         switch (rtn) {
926         case NEEDS_RETRY:
927                 if (retry_cnt--)
928                         goto retry_tur;
929                 /*FALLTHRU*/
930         case SUCCESS:
931                 return 0;
932         default:
933                 return 1;
934         }
935 }
936
937 /**
938  * scsi_eh_abort_cmds - abort pending commands.
939  * @work_q:     &list_head for pending commands.
940  * @done_q:     &list_head for processed commands.
941  *
942  * Decription:
943  *    Try and see whether or not it makes sense to try and abort the
944  *    running command.  This only works out to be the case if we have one
945  *    command that has timed out.  If the command simply failed, it makes
946  *    no sense to try and abort the command, since as far as the shost
947  *    adapter is concerned, it isn't running.
948  */
949 static int scsi_eh_abort_cmds(struct list_head *work_q,
950                               struct list_head *done_q)
951 {
952         struct scsi_cmnd *scmd, *next;
953         int rtn;
954
955         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
956                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
957                         continue;
958                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
959                                                   "0x%p\n", current->comm,
960                                                   scmd));
961                 rtn = scsi_try_to_abort_cmd(scmd);
962                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
963                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
964                         if (!scsi_device_online(scmd->device) ||
965                             rtn == FAST_IO_FAIL ||
966                             !scsi_eh_tur(scmd)) {
967                                 scsi_eh_finish_cmd(scmd, done_q);
968                         }
969                                 
970                 } else
971                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
972                                                           " cmd failed:"
973                                                           "0x%p\n",
974                                                           current->comm,
975                                                           scmd));
976         }
977
978         return list_empty(work_q);
979 }
980
981 /**
982  * scsi_eh_try_stu - Send START_UNIT to device.
983  * @scmd:       &scsi_cmnd to send START_UNIT
984  *
985  * Return value:
986  *    0 - Device is ready. 1 - Device NOT ready.
987  */
988 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
989 {
990         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
991
992         if (scmd->device->allow_restart) {
993                 int i, rtn = NEEDS_RETRY;
994
995                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
996                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
997
998                 if (rtn == SUCCESS)
999                         return 0;
1000         }
1001
1002         return 1;
1003 }
1004
1005  /**
1006  * scsi_eh_stu - send START_UNIT if needed
1007  * @shost:      &scsi host being recovered.
1008  * @work_q:     &list_head for pending commands.
1009  * @done_q:     &list_head for processed commands.
1010  *
1011  * Notes:
1012  *    If commands are failing due to not ready, initializing command required,
1013  *      try revalidating the device, which will end up sending a start unit. 
1014  */
1015 static int scsi_eh_stu(struct Scsi_Host *shost,
1016                               struct list_head *work_q,
1017                               struct list_head *done_q)
1018 {
1019         struct scsi_cmnd *scmd, *stu_scmd, *next;
1020         struct scsi_device *sdev;
1021
1022         shost_for_each_device(sdev, shost) {
1023                 stu_scmd = NULL;
1024                 list_for_each_entry(scmd, work_q, eh_entry)
1025                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1026                             scsi_check_sense(scmd) == FAILED ) {
1027                                 stu_scmd = scmd;
1028                                 break;
1029                         }
1030
1031                 if (!stu_scmd)
1032                         continue;
1033
1034                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1035                                                   " 0x%p\n", current->comm, sdev));
1036
1037                 if (!scsi_eh_try_stu(stu_scmd)) {
1038                         if (!scsi_device_online(sdev) ||
1039                             !scsi_eh_tur(stu_scmd)) {
1040                                 list_for_each_entry_safe(scmd, next,
1041                                                           work_q, eh_entry) {
1042                                         if (scmd->device == sdev)
1043                                                 scsi_eh_finish_cmd(scmd, done_q);
1044                                 }
1045                         }
1046                 } else {
1047                         SCSI_LOG_ERROR_RECOVERY(3,
1048                                                 printk("%s: START_UNIT failed to sdev:"
1049                                                        " 0x%p\n", current->comm, sdev));
1050                 }
1051         }
1052
1053         return list_empty(work_q);
1054 }
1055
1056
1057 /**
1058  * scsi_eh_bus_device_reset - send bdr if needed
1059  * @shost:      scsi host being recovered.
1060  * @work_q:     &list_head for pending commands.
1061  * @done_q:     &list_head for processed commands.
1062  *
1063  * Notes:
1064  *    Try a bus device reset.  Still, look to see whether we have multiple
1065  *    devices that are jammed or not - if we have multiple devices, it
1066  *    makes no sense to try bus_device_reset - we really would need to try
1067  *    a bus_reset instead. 
1068  */
1069 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1070                                     struct list_head *work_q,
1071                                     struct list_head *done_q)
1072 {
1073         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1074         struct scsi_device *sdev;
1075         int rtn;
1076
1077         shost_for_each_device(sdev, shost) {
1078                 bdr_scmd = NULL;
1079                 list_for_each_entry(scmd, work_q, eh_entry)
1080                         if (scmd->device == sdev) {
1081                                 bdr_scmd = scmd;
1082                                 break;
1083                         }
1084
1085                 if (!bdr_scmd)
1086                         continue;
1087
1088                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1089                                                   " 0x%p\n", current->comm,
1090                                                   sdev));
1091                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1092                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1093                         if (!scsi_device_online(sdev) ||
1094                             rtn == FAST_IO_FAIL ||
1095                             !scsi_eh_tur(bdr_scmd)) {
1096                                 list_for_each_entry_safe(scmd, next,
1097                                                          work_q, eh_entry) {
1098                                         if (scmd->device == sdev)
1099                                                 scsi_eh_finish_cmd(scmd,
1100                                                                    done_q);
1101                                 }
1102                         }
1103                 } else {
1104                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1105                                                           " failed sdev:"
1106                                                           "0x%p\n",
1107                                                           current->comm,
1108                                                            sdev));
1109                 }
1110         }
1111
1112         return list_empty(work_q);
1113 }
1114
1115 /**
1116  * scsi_eh_target_reset - send target reset if needed
1117  * @shost:      scsi host being recovered.
1118  * @work_q:     &list_head for pending commands.
1119  * @done_q:     &list_head for processed commands.
1120  *
1121  * Notes:
1122  *    Try a target reset.
1123  */
1124 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1125                                 struct list_head *work_q,
1126                                 struct list_head *done_q)
1127 {
1128         LIST_HEAD(tmp_list);
1129
1130         list_splice_init(work_q, &tmp_list);
1131
1132         while (!list_empty(&tmp_list)) {
1133                 struct scsi_cmnd *next, *scmd;
1134                 int rtn;
1135                 unsigned int id;
1136
1137                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1138                 id = scmd_id(scmd);
1139
1140                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1141                                                   "to target %d\n",
1142                                                   current->comm, id));
1143                 rtn = scsi_try_target_reset(scmd);
1144                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1145                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1146                                                           " failed target: "
1147                                                           "%d\n",
1148                                                           current->comm, id));
1149                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1150                         if (scmd_id(scmd) != id)
1151                                 continue;
1152
1153                         if ((rtn == SUCCESS || rtn == FAST_IO_FAIL)
1154                             && (!scsi_device_online(scmd->device) ||
1155                                  rtn == FAST_IO_FAIL || !scsi_eh_tur(scmd)))
1156                                 scsi_eh_finish_cmd(scmd, done_q);
1157                         else
1158                                 /* push back on work queue for further processing */
1159                                 list_move(&scmd->eh_entry, work_q);
1160                 }
1161         }
1162
1163         return list_empty(work_q);
1164 }
1165
1166 /**
1167  * scsi_eh_bus_reset - send a bus reset 
1168  * @shost:      &scsi host being recovered.
1169  * @work_q:     &list_head for pending commands.
1170  * @done_q:     &list_head for processed commands.
1171  */
1172 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1173                              struct list_head *work_q,
1174                              struct list_head *done_q)
1175 {
1176         struct scsi_cmnd *scmd, *chan_scmd, *next;
1177         unsigned int channel;
1178         int rtn;
1179
1180         /*
1181          * we really want to loop over the various channels, and do this on
1182          * a channel by channel basis.  we should also check to see if any
1183          * of the failed commands are on soft_reset devices, and if so, skip
1184          * the reset.  
1185          */
1186
1187         for (channel = 0; channel <= shost->max_channel; channel++) {
1188                 chan_scmd = NULL;
1189                 list_for_each_entry(scmd, work_q, eh_entry) {
1190                         if (channel == scmd_channel(scmd)) {
1191                                 chan_scmd = scmd;
1192                                 break;
1193                                 /*
1194                                  * FIXME add back in some support for
1195                                  * soft_reset devices.
1196                                  */
1197                         }
1198                 }
1199
1200                 if (!chan_scmd)
1201                         continue;
1202                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1203                                                   " %d\n", current->comm,
1204                                                   channel));
1205                 rtn = scsi_try_bus_reset(chan_scmd);
1206                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1207                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1208                                 if (channel == scmd_channel(scmd))
1209                                         if (!scsi_device_online(scmd->device) ||
1210                                             rtn == FAST_IO_FAIL ||
1211                                             !scsi_eh_tur(scmd))
1212                                                 scsi_eh_finish_cmd(scmd,
1213                                                                    done_q);
1214                         }
1215                 } else {
1216                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1217                                                           " failed chan: %d\n",
1218                                                           current->comm,
1219                                                           channel));
1220                 }
1221         }
1222         return list_empty(work_q);
1223 }
1224
1225 /**
1226  * scsi_eh_host_reset - send a host reset 
1227  * @work_q:     list_head for processed commands.
1228  * @done_q:     list_head for processed commands.
1229  */
1230 static int scsi_eh_host_reset(struct list_head *work_q,
1231                               struct list_head *done_q)
1232 {
1233         struct scsi_cmnd *scmd, *next;
1234         int rtn;
1235
1236         if (!list_empty(work_q)) {
1237                 scmd = list_entry(work_q->next,
1238                                   struct scsi_cmnd, eh_entry);
1239
1240                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1241                                                   , current->comm));
1242
1243                 rtn = scsi_try_host_reset(scmd);
1244                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1245                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1246                                 if (!scsi_device_online(scmd->device) ||
1247                                     rtn == FAST_IO_FAIL ||
1248                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1249                                     !scsi_eh_tur(scmd))
1250                                         scsi_eh_finish_cmd(scmd, done_q);
1251                         }
1252                 } else {
1253                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1254                                                           " failed\n",
1255                                                           current->comm));
1256                 }
1257         }
1258         return list_empty(work_q);
1259 }
1260
1261 /**
1262  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1263  * @work_q:     list_head for processed commands.
1264  * @done_q:     list_head for processed commands.
1265  */
1266 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1267                                   struct list_head *done_q)
1268 {
1269         struct scsi_cmnd *scmd, *next;
1270
1271         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1272                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1273                             "not ready after error recovery\n");
1274                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1275                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1276                         /*
1277                          * FIXME: Handle lost cmds.
1278                          */
1279                 }
1280                 scsi_eh_finish_cmd(scmd, done_q);
1281         }
1282         return;
1283 }
1284
1285 /**
1286  * scsi_noretry_cmd - determinte if command should be failed fast
1287  * @scmd:       SCSI cmd to examine.
1288  */
1289 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1290 {
1291         switch (host_byte(scmd->result)) {
1292         case DID_OK:
1293                 break;
1294         case DID_BUS_BUSY:
1295                 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1296         case DID_PARITY:
1297                 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1298         case DID_ERROR:
1299                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1300                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1301                         return 0;
1302                 /* fall through */
1303         case DID_SOFT_ERROR:
1304                 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1305         }
1306
1307         switch (status_byte(scmd->result)) {
1308         case CHECK_CONDITION:
1309                 /*
1310                  * assume caller has checked sense and determinted
1311                  * the check condition was retryable.
1312                  */
1313                 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1314                     scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1315                         return 1;
1316         }
1317
1318         return 0;
1319 }
1320
1321 /**
1322  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1323  * @scmd:       SCSI cmd to examine.
1324  *
1325  * Notes:
1326  *    This is *only* called when we are examining the status after sending
1327  *    out the actual data command.  any commands that are queued for error
1328  *    recovery (e.g. test_unit_ready) do *not* come through here.
1329  *
1330  *    When this routine returns failed, it means the error handler thread
1331  *    is woken.  In cases where the error code indicates an error that
1332  *    doesn't require the error handler read (i.e. we don't need to
1333  *    abort/reset), this function should return SUCCESS.
1334  */
1335 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1336 {
1337         int rtn;
1338
1339         /*
1340          * if the device is offline, then we clearly just pass the result back
1341          * up to the top level.
1342          */
1343         if (!scsi_device_online(scmd->device)) {
1344                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1345                                                   " as SUCCESS\n",
1346                                                   __func__));
1347                 return SUCCESS;
1348         }
1349
1350         /*
1351          * first check the host byte, to see if there is anything in there
1352          * that would indicate what we need to do.
1353          */
1354         switch (host_byte(scmd->result)) {
1355         case DID_PASSTHROUGH:
1356                 /*
1357                  * no matter what, pass this through to the upper layer.
1358                  * nuke this special code so that it looks like we are saying
1359                  * did_ok.
1360                  */
1361                 scmd->result &= 0xff00ffff;
1362                 return SUCCESS;
1363         case DID_OK:
1364                 /*
1365                  * looks good.  drop through, and check the next byte.
1366                  */
1367                 break;
1368         case DID_NO_CONNECT:
1369         case DID_BAD_TARGET:
1370         case DID_ABORT:
1371                 /*
1372                  * note - this means that we just report the status back
1373                  * to the top level driver, not that we actually think
1374                  * that it indicates SUCCESS.
1375                  */
1376                 return SUCCESS;
1377                 /*
1378                  * when the low level driver returns did_soft_error,
1379                  * it is responsible for keeping an internal retry counter 
1380                  * in order to avoid endless loops (db)
1381                  *
1382                  * actually this is a bug in this function here.  we should
1383                  * be mindful of the maximum number of retries specified
1384                  * and not get stuck in a loop.
1385                  */
1386         case DID_SOFT_ERROR:
1387                 goto maybe_retry;
1388         case DID_IMM_RETRY:
1389                 return NEEDS_RETRY;
1390
1391         case DID_REQUEUE:
1392                 return ADD_TO_MLQUEUE;
1393         case DID_TRANSPORT_DISRUPTED:
1394                 /*
1395                  * LLD/transport was disrupted during processing of the IO.
1396                  * The transport class is now blocked/blocking,
1397                  * and the transport will decide what to do with the IO
1398                  * based on its timers and recovery capablilities if
1399                  * there are enough retries.
1400                  */
1401                 goto maybe_retry;
1402         case DID_TRANSPORT_FAILFAST:
1403                 /*
1404                  * The transport decided to failfast the IO (most likely
1405                  * the fast io fail tmo fired), so send IO directly upwards.
1406                  */
1407                 return SUCCESS;
1408         case DID_ERROR:
1409                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1410                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1411                         /*
1412                          * execute reservation conflict processing code
1413                          * lower down
1414                          */
1415                         break;
1416                 /* fallthrough */
1417
1418         case DID_BUS_BUSY:
1419         case DID_PARITY:
1420                 goto maybe_retry;
1421         case DID_TIME_OUT:
1422                 /*
1423                  * when we scan the bus, we get timeout messages for
1424                  * these commands if there is no device available.
1425                  * other hosts report did_no_connect for the same thing.
1426                  */
1427                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1428                      scmd->cmnd[0] == INQUIRY)) {
1429                         return SUCCESS;
1430                 } else {
1431                         return FAILED;
1432                 }
1433         case DID_RESET:
1434                 return SUCCESS;
1435         default:
1436                 return FAILED;
1437         }
1438
1439         /*
1440          * next, check the message byte.
1441          */
1442         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1443                 return FAILED;
1444
1445         /*
1446          * check the status byte to see if this indicates anything special.
1447          */
1448         switch (status_byte(scmd->result)) {
1449         case QUEUE_FULL:
1450                 scsi_handle_queue_full(scmd->device);
1451                 /*
1452                  * the case of trying to send too many commands to a
1453                  * tagged queueing device.
1454                  */
1455         case BUSY:
1456                 /*
1457                  * device can't talk to us at the moment.  Should only
1458                  * occur (SAM-3) when the task queue is empty, so will cause
1459                  * the empty queue handling to trigger a stall in the
1460                  * device.
1461                  */
1462                 return ADD_TO_MLQUEUE;
1463         case GOOD:
1464                 scsi_handle_queue_ramp_up(scmd->device);
1465         case COMMAND_TERMINATED:
1466                 return SUCCESS;
1467         case TASK_ABORTED:
1468                 goto maybe_retry;
1469         case CHECK_CONDITION:
1470                 rtn = scsi_check_sense(scmd);
1471                 if (rtn == NEEDS_RETRY)
1472                         goto maybe_retry;
1473                 else if (rtn == TARGET_ERROR) {
1474                         /*
1475                          * Need to modify host byte to signal a
1476                          * permanent target failure
1477                          */
1478                         scmd->result |= (DID_TARGET_FAILURE << 16);
1479                         rtn = SUCCESS;
1480                 }
1481                 /* if rtn == FAILED, we have no sense information;
1482                  * returning FAILED will wake the error handler thread
1483                  * to collect the sense and redo the decide
1484                  * disposition */
1485                 return rtn;
1486         case CONDITION_GOOD:
1487         case INTERMEDIATE_GOOD:
1488         case INTERMEDIATE_C_GOOD:
1489         case ACA_ACTIVE:
1490                 /*
1491                  * who knows?  FIXME(eric)
1492                  */
1493                 return SUCCESS;
1494
1495         case RESERVATION_CONFLICT:
1496                 sdev_printk(KERN_INFO, scmd->device,
1497                             "reservation conflict\n");
1498                 scmd->result |= (DID_NEXUS_FAILURE << 16);
1499                 return SUCCESS; /* causes immediate i/o error */
1500         default:
1501                 return FAILED;
1502         }
1503         return FAILED;
1504
1505       maybe_retry:
1506
1507         /* we requeue for retry because the error was retryable, and
1508          * the request was not marked fast fail.  Note that above,
1509          * even if the request is marked fast fail, we still requeue
1510          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1511         if ((++scmd->retries) <= scmd->allowed
1512             && !scsi_noretry_cmd(scmd)) {
1513                 return NEEDS_RETRY;
1514         } else {
1515                 /*
1516                  * no more retries - report this one back to upper level.
1517                  */
1518                 return SUCCESS;
1519         }
1520 }
1521
1522 static void eh_lock_door_done(struct request *req, int uptodate)
1523 {
1524         __blk_put_request(req->q, req);
1525 }
1526
1527 /**
1528  * scsi_eh_lock_door - Prevent medium removal for the specified device
1529  * @sdev:       SCSI device to prevent medium removal
1530  *
1531  * Locking:
1532  *      We must be called from process context.
1533  *
1534  * Notes:
1535  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1536  *      head of the devices request queue, and continue.
1537  */
1538 static void scsi_eh_lock_door(struct scsi_device *sdev)
1539 {
1540         struct request *req;
1541
1542         /*
1543          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1544          * request becomes available
1545          */
1546         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1547
1548         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1549         req->cmd[1] = 0;
1550         req->cmd[2] = 0;
1551         req->cmd[3] = 0;
1552         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1553         req->cmd[5] = 0;
1554
1555         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1556
1557         req->cmd_type = REQ_TYPE_BLOCK_PC;
1558         req->cmd_flags |= REQ_QUIET;
1559         req->timeout = 10 * HZ;
1560         req->retries = 5;
1561
1562         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1563 }
1564
1565 /**
1566  * scsi_restart_operations - restart io operations to the specified host.
1567  * @shost:      Host we are restarting.
1568  *
1569  * Notes:
1570  *    When we entered the error handler, we blocked all further i/o to
1571  *    this device.  we need to 'reverse' this process.
1572  */
1573 static void scsi_restart_operations(struct Scsi_Host *shost)
1574 {
1575         struct scsi_device *sdev;
1576         unsigned long flags;
1577
1578         /*
1579          * If the door was locked, we need to insert a door lock request
1580          * onto the head of the SCSI request queue for the device.  There
1581          * is no point trying to lock the door of an off-line device.
1582          */
1583         shost_for_each_device(sdev, shost) {
1584                 if (scsi_device_online(sdev) && sdev->locked)
1585                         scsi_eh_lock_door(sdev);
1586         }
1587
1588         /*
1589          * next free up anything directly waiting upon the host.  this
1590          * will be requests for character device operations, and also for
1591          * ioctls to queued block devices.
1592          */
1593         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1594                                           __func__));
1595
1596         spin_lock_irqsave(shost->host_lock, flags);
1597         if (scsi_host_set_state(shost, SHOST_RUNNING))
1598                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1599                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1600         spin_unlock_irqrestore(shost->host_lock, flags);
1601
1602         wake_up(&shost->host_wait);
1603
1604         /*
1605          * finally we need to re-initiate requests that may be pending.  we will
1606          * have had everything blocked while error handling is taking place, and
1607          * now that error recovery is done, we will need to ensure that these
1608          * requests are started.
1609          */
1610         scsi_run_host_queues(shost);
1611 }
1612
1613 /**
1614  * scsi_eh_ready_devs - check device ready state and recover if not.
1615  * @shost:      host to be recovered.
1616  * @work_q:     &list_head for pending commands.
1617  * @done_q:     &list_head for processed commands.
1618  */
1619 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1620                         struct list_head *work_q,
1621                         struct list_head *done_q)
1622 {
1623         if (!scsi_eh_stu(shost, work_q, done_q))
1624                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1625                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1626                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1627                                         if (!scsi_eh_host_reset(work_q, done_q))
1628                                                 scsi_eh_offline_sdevs(work_q,
1629                                                                       done_q);
1630 }
1631 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1632
1633 /**
1634  * scsi_eh_flush_done_q - finish processed commands or retry them.
1635  * @done_q:     list_head of processed commands.
1636  */
1637 void scsi_eh_flush_done_q(struct list_head *done_q)
1638 {
1639         struct scsi_cmnd *scmd, *next;
1640
1641         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1642                 list_del_init(&scmd->eh_entry);
1643                 if (scsi_device_online(scmd->device) &&
1644                     !scsi_noretry_cmd(scmd) &&
1645                     (++scmd->retries <= scmd->allowed)) {
1646                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1647                                                           " retry cmd: %p\n",
1648                                                           current->comm,
1649                                                           scmd));
1650                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1651                 } else {
1652                         /*
1653                          * If just we got sense for the device (called
1654                          * scsi_eh_get_sense), scmd->result is already
1655                          * set, do not set DRIVER_TIMEOUT.
1656                          */
1657                         if (!scmd->result)
1658                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1659                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1660                                                         " cmd: %p\n",
1661                                                         current->comm, scmd));
1662                         scsi_finish_command(scmd);
1663                 }
1664         }
1665 }
1666 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1667
1668 /**
1669  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1670  * @shost:      Host to unjam.
1671  *
1672  * Notes:
1673  *    When we come in here, we *know* that all commands on the bus have
1674  *    either completed, failed or timed out.  we also know that no further
1675  *    commands are being sent to the host, so things are relatively quiet
1676  *    and we have freedom to fiddle with things as we wish.
1677  *
1678  *    This is only the *default* implementation.  it is possible for
1679  *    individual drivers to supply their own version of this function, and
1680  *    if the maintainer wishes to do this, it is strongly suggested that
1681  *    this function be taken as a template and modified.  this function
1682  *    was designed to correctly handle problems for about 95% of the
1683  *    different cases out there, and it should always provide at least a
1684  *    reasonable amount of error recovery.
1685  *
1686  *    Any command marked 'failed' or 'timeout' must eventually have
1687  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1688  *    here, so when we restart the host after we return it should have an
1689  *    empty queue.
1690  */
1691 static void scsi_unjam_host(struct Scsi_Host *shost)
1692 {
1693         unsigned long flags;
1694         LIST_HEAD(eh_work_q);
1695         LIST_HEAD(eh_done_q);
1696
1697         spin_lock_irqsave(shost->host_lock, flags);
1698         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1699         spin_unlock_irqrestore(shost->host_lock, flags);
1700
1701         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1702
1703         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1704                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1705                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1706
1707         scsi_eh_flush_done_q(&eh_done_q);
1708 }
1709
1710 /**
1711  * scsi_error_handler - SCSI error handler thread
1712  * @data:       Host for which we are running.
1713  *
1714  * Notes:
1715  *    This is the main error handling loop.  This is run as a kernel thread
1716  *    for every SCSI host and handles all error handling activity.
1717  */
1718 int scsi_error_handler(void *data)
1719 {
1720         struct Scsi_Host *shost = data;
1721
1722         /*
1723          * We use TASK_INTERRUPTIBLE so that the thread is not
1724          * counted against the load average as a running process.
1725          * We never actually get interrupted because kthread_run
1726          * disables signal delivery for the created thread.
1727          */
1728         set_current_state(TASK_INTERRUPTIBLE);
1729         while (!kthread_should_stop()) {
1730                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1731                     shost->host_failed != shost->host_busy) {
1732                         SCSI_LOG_ERROR_RECOVERY(1,
1733                                 printk("Error handler scsi_eh_%d sleeping\n",
1734                                         shost->host_no));
1735                         schedule();
1736                         set_current_state(TASK_INTERRUPTIBLE);
1737                         continue;
1738                 }
1739
1740                 __set_current_state(TASK_RUNNING);
1741                 SCSI_LOG_ERROR_RECOVERY(1,
1742                         printk("Error handler scsi_eh_%d waking up\n",
1743                                 shost->host_no));
1744
1745                 /*
1746                  * We have a host that is failing for some reason.  Figure out
1747                  * what we need to do to get it up and online again (if we can).
1748                  * If we fail, we end up taking the thing offline.
1749                  */
1750                 if (scsi_autopm_get_host(shost) != 0) {
1751                         SCSI_LOG_ERROR_RECOVERY(1,
1752                                 printk(KERN_ERR "Error handler scsi_eh_%d "
1753                                                 "unable to autoresume\n",
1754                                                 shost->host_no));
1755                         continue;
1756                 }
1757
1758                 if (shost->transportt->eh_strategy_handler)
1759                         shost->transportt->eh_strategy_handler(shost);
1760                 else
1761                         scsi_unjam_host(shost);
1762
1763                 /*
1764                  * Note - if the above fails completely, the action is to take
1765                  * individual devices offline and flush the queue of any
1766                  * outstanding requests that may have been pending.  When we
1767                  * restart, we restart any I/O to any other devices on the bus
1768                  * which are still online.
1769                  */
1770                 scsi_restart_operations(shost);
1771                 scsi_autopm_put_host(shost);
1772                 set_current_state(TASK_INTERRUPTIBLE);
1773         }
1774         __set_current_state(TASK_RUNNING);
1775
1776         SCSI_LOG_ERROR_RECOVERY(1,
1777                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1778         shost->ehandler = NULL;
1779         return 0;
1780 }
1781
1782 /*
1783  * Function:    scsi_report_bus_reset()
1784  *
1785  * Purpose:     Utility function used by low-level drivers to report that
1786  *              they have observed a bus reset on the bus being handled.
1787  *
1788  * Arguments:   shost       - Host in question
1789  *              channel     - channel on which reset was observed.
1790  *
1791  * Returns:     Nothing
1792  *
1793  * Lock status: Host lock must be held.
1794  *
1795  * Notes:       This only needs to be called if the reset is one which
1796  *              originates from an unknown location.  Resets originated
1797  *              by the mid-level itself don't need to call this, but there
1798  *              should be no harm.
1799  *
1800  *              The main purpose of this is to make sure that a CHECK_CONDITION
1801  *              is properly treated.
1802  */
1803 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1804 {
1805         struct scsi_device *sdev;
1806
1807         __shost_for_each_device(sdev, shost) {
1808                 if (channel == sdev_channel(sdev))
1809                         __scsi_report_device_reset(sdev, NULL);
1810         }
1811 }
1812 EXPORT_SYMBOL(scsi_report_bus_reset);
1813
1814 /*
1815  * Function:    scsi_report_device_reset()
1816  *
1817  * Purpose:     Utility function used by low-level drivers to report that
1818  *              they have observed a device reset on the device being handled.
1819  *
1820  * Arguments:   shost       - Host in question
1821  *              channel     - channel on which reset was observed
1822  *              target      - target on which reset was observed
1823  *
1824  * Returns:     Nothing
1825  *
1826  * Lock status: Host lock must be held
1827  *
1828  * Notes:       This only needs to be called if the reset is one which
1829  *              originates from an unknown location.  Resets originated
1830  *              by the mid-level itself don't need to call this, but there
1831  *              should be no harm.
1832  *
1833  *              The main purpose of this is to make sure that a CHECK_CONDITION
1834  *              is properly treated.
1835  */
1836 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1837 {
1838         struct scsi_device *sdev;
1839
1840         __shost_for_each_device(sdev, shost) {
1841                 if (channel == sdev_channel(sdev) &&
1842                     target == sdev_id(sdev))
1843                         __scsi_report_device_reset(sdev, NULL);
1844         }
1845 }
1846 EXPORT_SYMBOL(scsi_report_device_reset);
1847
1848 static void
1849 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1850 {
1851 }
1852
1853 /*
1854  * Function:    scsi_reset_provider
1855  *
1856  * Purpose:     Send requested reset to a bus or device at any phase.
1857  *
1858  * Arguments:   device  - device to send reset to
1859  *              flag - reset type (see scsi.h)
1860  *
1861  * Returns:     SUCCESS/FAILURE.
1862  *
1863  * Notes:       This is used by the SCSI Generic driver to provide
1864  *              Bus/Device reset capability.
1865  */
1866 int
1867 scsi_reset_provider(struct scsi_device *dev, int flag)
1868 {
1869         struct scsi_cmnd *scmd;
1870         struct Scsi_Host *shost = dev->host;
1871         struct request req;
1872         unsigned long flags;
1873         int rtn;
1874
1875         if (scsi_autopm_get_host(shost) < 0)
1876                 return FAILED;
1877
1878         scmd = scsi_get_command(dev, GFP_KERNEL);
1879         blk_rq_init(NULL, &req);
1880         scmd->request = &req;
1881
1882         scmd->cmnd = req.cmd;
1883
1884         scmd->scsi_done         = scsi_reset_provider_done_command;
1885         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1886
1887         scmd->cmd_len                   = 0;
1888
1889         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1890
1891         spin_lock_irqsave(shost->host_lock, flags);
1892         shost->tmf_in_progress = 1;
1893         spin_unlock_irqrestore(shost->host_lock, flags);
1894
1895         switch (flag) {
1896         case SCSI_TRY_RESET_DEVICE:
1897                 rtn = scsi_try_bus_device_reset(scmd);
1898                 if (rtn == SUCCESS)
1899                         break;
1900                 /* FALLTHROUGH */
1901         case SCSI_TRY_RESET_TARGET:
1902                 rtn = scsi_try_target_reset(scmd);
1903                 if (rtn == SUCCESS)
1904                         break;
1905                 /* FALLTHROUGH */
1906         case SCSI_TRY_RESET_BUS:
1907                 rtn = scsi_try_bus_reset(scmd);
1908                 if (rtn == SUCCESS)
1909                         break;
1910                 /* FALLTHROUGH */
1911         case SCSI_TRY_RESET_HOST:
1912                 rtn = scsi_try_host_reset(scmd);
1913                 break;
1914         default:
1915                 rtn = FAILED;
1916         }
1917
1918         spin_lock_irqsave(shost->host_lock, flags);
1919         shost->tmf_in_progress = 0;
1920         spin_unlock_irqrestore(shost->host_lock, flags);
1921
1922         /*
1923          * be sure to wake up anyone who was sleeping or had their queue
1924          * suspended while we performed the TMF.
1925          */
1926         SCSI_LOG_ERROR_RECOVERY(3,
1927                 printk("%s: waking up host to restart after TMF\n",
1928                 __func__));
1929
1930         wake_up(&shost->host_wait);
1931
1932         scsi_run_host_queues(shost);
1933
1934         scsi_next_command(scmd);
1935         scsi_autopm_put_host(shost);
1936         return rtn;
1937 }
1938 EXPORT_SYMBOL(scsi_reset_provider);
1939
1940 /**
1941  * scsi_normalize_sense - normalize main elements from either fixed or
1942  *                      descriptor sense data format into a common format.
1943  *
1944  * @sense_buffer:       byte array containing sense data returned by device
1945  * @sb_len:             number of valid bytes in sense_buffer
1946  * @sshdr:              pointer to instance of structure that common
1947  *                      elements are written to.
1948  *
1949  * Notes:
1950  *      The "main elements" from sense data are: response_code, sense_key,
1951  *      asc, ascq and additional_length (only for descriptor format).
1952  *
1953  *      Typically this function can be called after a device has
1954  *      responded to a SCSI command with the CHECK_CONDITION status.
1955  *
1956  * Return value:
1957  *      1 if valid sense data information found, else 0;
1958  */
1959 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1960                          struct scsi_sense_hdr *sshdr)
1961 {
1962         if (!sense_buffer || !sb_len)
1963                 return 0;
1964
1965         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1966
1967         sshdr->response_code = (sense_buffer[0] & 0x7f);
1968
1969         if (!scsi_sense_valid(sshdr))
1970                 return 0;
1971
1972         if (sshdr->response_code >= 0x72) {
1973                 /*
1974                  * descriptor format
1975                  */
1976                 if (sb_len > 1)
1977                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1978                 if (sb_len > 2)
1979                         sshdr->asc = sense_buffer[2];
1980                 if (sb_len > 3)
1981                         sshdr->ascq = sense_buffer[3];
1982                 if (sb_len > 7)
1983                         sshdr->additional_length = sense_buffer[7];
1984         } else {
1985                 /* 
1986                  * fixed format
1987                  */
1988                 if (sb_len > 2)
1989                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1990                 if (sb_len > 7) {
1991                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1992                                          sb_len : (sense_buffer[7] + 8);
1993                         if (sb_len > 12)
1994                                 sshdr->asc = sense_buffer[12];
1995                         if (sb_len > 13)
1996                                 sshdr->ascq = sense_buffer[13];
1997                 }
1998         }
1999
2000         return 1;
2001 }
2002 EXPORT_SYMBOL(scsi_normalize_sense);
2003
2004 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
2005                                  struct scsi_sense_hdr *sshdr)
2006 {
2007         return scsi_normalize_sense(cmd->sense_buffer,
2008                         SCSI_SENSE_BUFFERSIZE, sshdr);
2009 }
2010 EXPORT_SYMBOL(scsi_command_normalize_sense);
2011
2012 /**
2013  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
2014  * @sense_buffer:       byte array of descriptor format sense data
2015  * @sb_len:             number of valid bytes in sense_buffer
2016  * @desc_type:          value of descriptor type to find
2017  *                      (e.g. 0 -> information)
2018  *
2019  * Notes:
2020  *      only valid when sense data is in descriptor format
2021  *
2022  * Return value:
2023  *      pointer to start of (first) descriptor if found else NULL
2024  */
2025 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2026                                 int desc_type)
2027 {
2028         int add_sen_len, add_len, desc_len, k;
2029         const u8 * descp;
2030
2031         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2032                 return NULL;
2033         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2034                 return NULL;
2035         add_sen_len = (add_sen_len < (sb_len - 8)) ?
2036                         add_sen_len : (sb_len - 8);
2037         descp = &sense_buffer[8];
2038         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2039                 descp += desc_len;
2040                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2041                 desc_len = add_len + 2;
2042                 if (descp[0] == desc_type)
2043                         return descp;
2044                 if (add_len < 0) // short descriptor ??
2045                         break;
2046         }
2047         return NULL;
2048 }
2049 EXPORT_SYMBOL(scsi_sense_desc_find);
2050
2051 /**
2052  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2053  * @sense_buffer:       byte array of sense data
2054  * @sb_len:             number of valid bytes in sense_buffer
2055  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2056  *                      field will be placed if found.
2057  *
2058  * Return value:
2059  *      1 if information field found, 0 if not found.
2060  */
2061 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2062                             u64 * info_out)
2063 {
2064         int j;
2065         const u8 * ucp;
2066         u64 ull;
2067
2068         if (sb_len < 7)
2069                 return 0;
2070         switch (sense_buffer[0] & 0x7f) {
2071         case 0x70:
2072         case 0x71:
2073                 if (sense_buffer[0] & 0x80) {
2074                         *info_out = (sense_buffer[3] << 24) +
2075                                     (sense_buffer[4] << 16) +
2076                                     (sense_buffer[5] << 8) + sense_buffer[6];
2077                         return 1;
2078                 } else
2079                         return 0;
2080         case 0x72:
2081         case 0x73:
2082                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2083                                            0 /* info desc */);
2084                 if (ucp && (0xa == ucp[1])) {
2085                         ull = 0;
2086                         for (j = 0; j < 8; ++j) {
2087                                 if (j > 0)
2088                                         ull <<= 8;
2089                                 ull |= ucp[4 + j];
2090                         }
2091                         *info_out = ull;
2092                         return 1;
2093                 } else
2094                         return 0;
2095         default:
2096                 return 0;
2097         }
2098 }
2099 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2100
2101 /**
2102  * scsi_build_sense_buffer - build sense data in a buffer
2103  * @desc:       Sense format (non zero == descriptor format,
2104  *              0 == fixed format)
2105  * @buf:        Where to build sense data
2106  * @key:        Sense key
2107  * @asc:        Additional sense code
2108  * @ascq:       Additional sense code qualifier
2109  *
2110  **/
2111 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2112 {
2113         if (desc) {
2114                 buf[0] = 0x72;  /* descriptor, current */
2115                 buf[1] = key;
2116                 buf[2] = asc;
2117                 buf[3] = ascq;
2118                 buf[7] = 0;
2119         } else {
2120                 buf[0] = 0x70;  /* fixed, current */
2121                 buf[2] = key;
2122                 buf[7] = 0xa;
2123                 buf[12] = asc;
2124                 buf[13] = ascq;
2125         }
2126 }
2127 EXPORT_SYMBOL(scsi_build_sense_buffer);