2 * scsi_error.c Copyright (C) 1997 Eric Youngdale
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.
9 * Restructured scsi_unjam_host and associated functions.
10 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
12 * Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
14 * September 30, 2002 Mike Anderson (andmike@us.ibm.com)
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/timer.h>
20 #include <linux/string.h>
21 #include <linux/slab.h>
22 #include <linux/kernel.h>
23 #include <linux/kthread.h>
24 #include <linux/interrupt.h>
25 #include <linux/blkdev.h>
26 #include <linux/delay.h>
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_dbg.h>
30 #include <scsi/scsi_device.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_transport.h>
33 #include <scsi/scsi_host.h>
34 #include <scsi/scsi_ioctl.h>
35 #include <scsi/scsi_request.h>
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
40 #define SENSE_TIMEOUT (10*HZ)
41 #define START_UNIT_TIMEOUT (30*HZ)
44 * These should *probably* be handled by the host itself.
45 * Since it is allowed to sleep, it probably should.
47 #define BUS_RESET_SETTLE_TIME (10)
48 #define HOST_RESET_SETTLE_TIME (10)
50 /* called with shost->host_lock held */
51 void scsi_eh_wakeup(struct Scsi_Host *shost)
53 if (shost->host_busy == shost->host_failed) {
54 wake_up_process(shost->ehandler);
55 SCSI_LOG_ERROR_RECOVERY(5,
56 printk("Waking error handler thread\n"));
61 * scsi_eh_scmd_add - add scsi cmd to error handling.
62 * @scmd: scmd to run eh on.
63 * @eh_flag: optional SCSI_EH flag.
68 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
70 struct Scsi_Host *shost = scmd->device->host;
77 spin_lock_irqsave(shost->host_lock, flags);
78 if (scsi_host_set_state(shost, SHOST_RECOVERY))
79 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
83 scmd->eh_eflags |= eh_flag;
84 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
86 scsi_eh_wakeup(shost);
88 spin_unlock_irqrestore(shost->host_lock, flags);
93 * scsi_add_timer - Start timeout timer for a single scsi command.
94 * @scmd: scsi command that is about to start running.
95 * @timeout: amount of time to allow this command to run.
96 * @complete: timeout function to call if timer isn't canceled.
99 * This should be turned into an inline function. Each scsi command
100 * has its own timer, and as it is added to the queue, we set up the
101 * timer. When the command completes, we cancel the timer.
103 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
104 void (*complete)(struct scsi_cmnd *))
108 * If the clock was already running for this command, then
109 * first delete the timer. The timer handling code gets rather
110 * confused if we don't do this.
112 if (scmd->eh_timeout.function)
113 del_timer(&scmd->eh_timeout);
115 scmd->eh_timeout.data = (unsigned long)scmd;
116 scmd->eh_timeout.expires = jiffies + timeout;
117 scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
119 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
120 " %d, (%p)\n", __FUNCTION__,
121 scmd, timeout, complete));
123 add_timer(&scmd->eh_timeout);
127 * scsi_delete_timer - Delete/cancel timer for a given function.
128 * @scmd: Cmd that we are canceling timer for
131 * This should be turned into an inline function.
134 * 1 if we were able to detach the timer. 0 if we blew it, and the
135 * timer function has already started to run.
137 int scsi_delete_timer(struct scsi_cmnd *scmd)
141 rtn = del_timer(&scmd->eh_timeout);
143 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
144 " rtn: %d\n", __FUNCTION__,
147 scmd->eh_timeout.data = (unsigned long)NULL;
148 scmd->eh_timeout.function = NULL;
154 * scsi_times_out - Timeout function for normal scsi commands.
155 * @scmd: Cmd that is timing out.
158 * We do not need to lock this. There is the potential for a race
159 * only in that the normal completion handling might run, but if the
160 * normal completion function determines that the timer has already
161 * fired, then it mustn't do anything.
163 void scsi_times_out(struct scsi_cmnd *scmd)
165 scsi_log_completion(scmd, TIMEOUT_ERROR);
167 if (scmd->device->host->transportt->eh_timed_out)
168 switch (scmd->device->host->transportt->eh_timed_out(scmd)) {
173 scsi_add_timer(scmd, scmd->timeout_per_command,
180 if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
181 scmd->result |= DID_TIME_OUT << 16;
187 * scsi_block_when_processing_errors - Prevent cmds from being queued.
188 * @sdev: Device on which we are performing recovery.
191 * We block until the host is out of error recovery, and then check to
192 * see whether the host or the device is offline.
195 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
197 int scsi_block_when_processing_errors(struct scsi_device *sdev)
201 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
203 online = scsi_device_online(sdev);
205 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
210 EXPORT_SYMBOL(scsi_block_when_processing_errors);
212 #ifdef CONFIG_SCSI_LOGGING
214 * scsi_eh_prt_fail_stats - Log info on failures.
215 * @shost: scsi host being recovered.
216 * @work_q: Queue of scsi cmds to process.
218 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
219 struct list_head *work_q)
221 struct scsi_cmnd *scmd;
222 struct scsi_device *sdev;
223 int total_failures = 0;
226 int devices_failed = 0;
228 shost_for_each_device(sdev, shost) {
229 list_for_each_entry(scmd, work_q, eh_entry) {
230 if (scmd->device == sdev) {
232 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
239 if (cmd_cancel || cmd_failed) {
240 SCSI_LOG_ERROR_RECOVERY(3,
241 sdev_printk(KERN_INFO, sdev,
242 "%s: cmds failed: %d, cancel: %d\n",
243 __FUNCTION__, cmd_failed,
251 SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
252 " devices require eh work\n",
253 total_failures, devices_failed));
258 * scsi_check_sense - Examine scsi cmd sense
259 * @scmd: Cmd to have sense checked.
262 * SUCCESS or FAILED or NEEDS_RETRY
265 * When a deferred error is detected the current command has
266 * not been executed and needs retrying.
268 static int scsi_check_sense(struct scsi_cmnd *scmd)
270 struct scsi_sense_hdr sshdr;
272 if (! scsi_command_normalize_sense(scmd, &sshdr))
273 return FAILED; /* no valid sense data */
275 if (scsi_sense_is_deferred(&sshdr))
279 * Previous logic looked for FILEMARK, EOM or ILI which are
280 * mainly associated with tapes and returned SUCCESS.
282 if (sshdr.response_code == 0x70) {
284 if (scmd->sense_buffer[2] & 0xe0)
288 * descriptor format: look for "stream commands sense data
289 * descriptor" (see SSC-3). Assume single sense data
290 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
292 if ((sshdr.additional_length > 3) &&
293 (scmd->sense_buffer[8] == 0x4) &&
294 (scmd->sense_buffer[11] & 0xe0))
298 switch (sshdr.sense_key) {
301 case RECOVERED_ERROR:
302 return /* soft_error */ SUCCESS;
304 case ABORTED_COMMAND:
309 * if we are expecting a cc/ua because of a bus reset that we
310 * performed, treat this just as a retry. otherwise this is
311 * information that we should pass up to the upper-level driver
312 * so that we can deal with it there.
314 if (scmd->device->expecting_cc_ua) {
315 scmd->device->expecting_cc_ua = 0;
319 * if the device is in the process of becoming ready, we
322 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
325 * if the device is not started, we need to wake
326 * the error handler to start the motor
328 if (scmd->device->allow_restart &&
329 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
333 /* these three are not supported */
335 case VOLUME_OVERFLOW:
343 if (scmd->device->retry_hwerror)
348 case ILLEGAL_REQUEST:
357 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
358 * @scmd: SCSI cmd to examine.
361 * This is *only* called when we are examining the status of commands
362 * queued during error recovery. the main difference here is that we
363 * don't allow for the possibility of retries here, and we are a lot
364 * more restrictive about what we consider acceptable.
366 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
369 * first check the host byte, to see if there is anything in there
370 * that would indicate what we need to do.
372 if (host_byte(scmd->result) == DID_RESET) {
374 * rats. we are already in the error handler, so we now
375 * get to try and figure out what to do next. if the sense
376 * is valid, we have a pretty good idea of what to do.
377 * if not, we mark it as FAILED.
379 return scsi_check_sense(scmd);
381 if (host_byte(scmd->result) != DID_OK)
385 * next, check the message byte.
387 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
391 * now, check the status byte to see if this indicates
394 switch (status_byte(scmd->result)) {
396 case COMMAND_TERMINATED:
398 case CHECK_CONDITION:
399 return scsi_check_sense(scmd);
401 case INTERMEDIATE_GOOD:
402 case INTERMEDIATE_C_GOOD:
404 * who knows? FIXME(eric)
409 case RESERVATION_CONFLICT:
417 * scsi_eh_done - Completion function for error handling.
418 * @scmd: Cmd that is done.
420 static void scsi_eh_done(struct scsi_cmnd *scmd)
422 struct completion *eh_action;
424 SCSI_LOG_ERROR_RECOVERY(3,
425 printk("%s scmd: %p result: %x\n",
426 __FUNCTION__, scmd, scmd->result));
428 eh_action = scmd->device->host->eh_action;
434 * scsi_send_eh_cmnd - send a cmd to a device as part of error recovery.
435 * @scmd: SCSI Cmd to send.
436 * @timeout: Timeout for cmd.
439 * SUCCESS or FAILED or NEEDS_RETRY
441 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
443 struct scsi_device *sdev = scmd->device;
444 struct Scsi_Host *shost = sdev->host;
445 DECLARE_COMPLETION(done);
446 unsigned long timeleft;
450 if (sdev->scsi_level <= SCSI_2)
451 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
452 (sdev->lun << 5 & 0xe0);
454 shost->eh_action = &done;
455 scmd->request->rq_status = RQ_SCSI_BUSY;
457 spin_lock_irqsave(shost->host_lock, flags);
459 shost->hostt->queuecommand(scmd, scsi_eh_done);
460 spin_unlock_irqrestore(shost->host_lock, flags);
462 timeleft = wait_for_completion_timeout(&done, timeout);
464 scmd->request->rq_status = RQ_SCSI_DONE;
465 shost->eh_action = NULL;
467 scsi_log_completion(scmd, SUCCESS);
469 SCSI_LOG_ERROR_RECOVERY(3,
470 printk("%s: scmd: %p, timeleft: %ld\n",
471 __FUNCTION__, scmd, timeleft));
474 * If there is time left scsi_eh_done got called, and we will
475 * examine the actual status codes to see whether the command
476 * actually did complete normally, else tell the host to forget
477 * about this command.
480 rtn = scsi_eh_completed_normally(scmd);
481 SCSI_LOG_ERROR_RECOVERY(3,
482 printk("%s: scsi_eh_completed_normally %x\n",
496 * FIXME(eric) - we are not tracking whether we could
497 * abort a timed out command or not. not sure how
498 * we should treat them differently anyways.
500 if (shost->hostt->eh_abort_handler)
501 shost->hostt->eh_abort_handler(scmd);
509 * scsi_request_sense - Request sense data from a particular target.
510 * @scmd: SCSI cmd for request sense.
513 * Some hosts automatically obtain this information, others require
514 * that we obtain it on our own. This function will *not* return until
515 * the command either times out, or it completes.
517 static int scsi_request_sense(struct scsi_cmnd *scmd)
519 static unsigned char generic_sense[6] =
520 {REQUEST_SENSE, 0, 0, 0, 252, 0};
521 unsigned char *scsi_result;
525 memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
527 scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
530 if (unlikely(!scsi_result)) {
531 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
537 * zero the sense buffer. some host adapters automatically always
538 * request sense, so it is not a good idea that
539 * scmd->request_buffer and scmd->sense_buffer point to the same
540 * address (db). 0 is not a valid sense code.
542 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
543 memset(scsi_result, 0, 252);
545 saved_result = scmd->result;
546 scmd->request_buffer = scsi_result;
547 scmd->request_bufflen = 252;
549 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
550 scmd->sc_data_direction = DMA_FROM_DEVICE;
553 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
555 /* last chance to have valid sense data */
556 if(!SCSI_SENSE_VALID(scmd)) {
557 memcpy(scmd->sense_buffer, scmd->request_buffer,
558 sizeof(scmd->sense_buffer));
564 * when we eventually call scsi_finish, we really wish to complete
565 * the original request, so let's restore the original data. (db)
567 scsi_setup_cmd_retry(scmd);
568 scmd->result = saved_result;
573 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
574 * @scmd: Original SCSI cmd that eh has finished.
575 * @done_q: Queue for processed commands.
578 * We don't want to use the normal command completion while we are are
579 * still handling errors - it may cause other commands to be queued,
580 * and that would disturb what we are doing. thus we really want to
581 * keep a list of pending commands for final completion, and once we
582 * are ready to leave error handling we handle completion for real.
584 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
586 scmd->device->host->host_failed--;
590 * set this back so that the upper level can correctly free up
593 scsi_setup_cmd_retry(scmd);
594 list_move_tail(&scmd->eh_entry, done_q);
596 EXPORT_SYMBOL(scsi_eh_finish_cmd);
599 * scsi_eh_get_sense - Get device sense data.
600 * @work_q: Queue of commands to process.
601 * @done_q: Queue of proccessed commands..
604 * See if we need to request sense information. if so, then get it
605 * now, so we have a better idea of what to do.
608 * This has the unfortunate side effect that if a shost adapter does
609 * not automatically request sense information, that we end up shutting
610 * it down before we request it.
612 * All drivers should request sense information internally these days,
613 * so for now all I have to say is tough noogies if you end up in here.
615 * XXX: Long term this code should go away, but that needs an audit of
618 static int scsi_eh_get_sense(struct list_head *work_q,
619 struct list_head *done_q)
621 struct scsi_cmnd *scmd, *next;
624 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
625 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
626 SCSI_SENSE_VALID(scmd))
629 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
630 "%s: requesting sense\n",
632 rtn = scsi_request_sense(scmd);
636 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
637 " result %x\n", scmd,
639 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
641 rtn = scsi_decide_disposition(scmd);
644 * if the result was normal, then just pass it along to the
648 /* we don't want this command reissued, just
649 * finished with the sense data, so set
650 * retries to the max allowed to ensure it
651 * won't get reissued */
652 scmd->retries = scmd->allowed;
653 else if (rtn != NEEDS_RETRY)
656 scsi_eh_finish_cmd(scmd, done_q);
659 return list_empty(work_q);
663 * scsi_try_to_abort_cmd - Ask host to abort a running command.
664 * @scmd: SCSI cmd to abort from Lower Level.
667 * This function will not return until the user's completion function
668 * has been called. there is no timeout on this operation. if the
669 * author of the low-level driver wishes this operation to be timed,
670 * they can provide this facility themselves. helper functions in
671 * scsi_error.c can be supplied to make this easier to do.
673 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
675 if (!scmd->device->host->hostt->eh_abort_handler)
679 * scsi_done was called just after the command timed out and before
680 * we had a chance to process it. (db)
682 if (scmd->serial_number == 0)
684 return scmd->device->host->hostt->eh_abort_handler(scmd);
688 * scsi_eh_tur - Send TUR to device.
689 * @scmd: Scsi cmd to send TUR
692 * 0 - Device is ready. 1 - Device NOT ready.
694 static int scsi_eh_tur(struct scsi_cmnd *scmd)
696 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
697 int retry_cnt = 1, rtn;
701 memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
704 * zero the sense buffer. the scsi spec mandates that any
705 * untransferred sense data should be interpreted as being zero.
707 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
709 saved_result = scmd->result;
710 scmd->request_buffer = NULL;
711 scmd->request_bufflen = 0;
713 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
715 scmd->sc_data_direction = DMA_NONE;
717 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
720 * when we eventually call scsi_finish, we really wish to complete
721 * the original request, so let's restore the original data. (db)
723 scsi_setup_cmd_retry(scmd);
724 scmd->result = saved_result;
727 * hey, we are done. let's look to see what happened.
729 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
730 __FUNCTION__, scmd, rtn));
733 else if (rtn == NEEDS_RETRY) {
742 * scsi_eh_abort_cmds - abort canceled commands.
743 * @shost: scsi host being recovered.
744 * @eh_done_q: list_head for processed commands.
747 * Try and see whether or not it makes sense to try and abort the
748 * running command. this only works out to be the case if we have one
749 * command that has timed out. if the command simply failed, it makes
750 * no sense to try and abort the command, since as far as the shost
751 * adapter is concerned, it isn't running.
753 static int scsi_eh_abort_cmds(struct list_head *work_q,
754 struct list_head *done_q)
756 struct scsi_cmnd *scmd, *next;
759 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
760 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
762 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
763 "0x%p\n", current->comm,
765 rtn = scsi_try_to_abort_cmd(scmd);
766 if (rtn == SUCCESS) {
767 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
768 if (!scsi_device_online(scmd->device) ||
769 !scsi_eh_tur(scmd)) {
770 scsi_eh_finish_cmd(scmd, done_q);
774 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
781 return list_empty(work_q);
785 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
786 * @scmd: SCSI cmd used to send BDR
789 * There is no timeout for this operation. if this operation is
790 * unreliable for a given host, then the host itself needs to put a
791 * timer on it, and set the host back to a consistent state prior to
794 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
798 if (!scmd->device->host->hostt->eh_device_reset_handler)
801 rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
802 if (rtn == SUCCESS) {
803 scmd->device->was_reset = 1;
804 scmd->device->expecting_cc_ua = 1;
811 * scsi_eh_try_stu - Send START_UNIT to device.
812 * @scmd: Scsi cmd to send START_UNIT
815 * 0 - Device is ready. 1 - Device NOT ready.
817 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
819 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
823 if (!scmd->device->allow_restart)
826 memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
829 * zero the sense buffer. the scsi spec mandates that any
830 * untransferred sense data should be interpreted as being zero.
832 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
834 saved_result = scmd->result;
835 scmd->request_buffer = NULL;
836 scmd->request_bufflen = 0;
838 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
840 scmd->sc_data_direction = DMA_NONE;
842 rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
845 * when we eventually call scsi_finish, we really wish to complete
846 * the original request, so let's restore the original data. (db)
848 scsi_setup_cmd_retry(scmd);
849 scmd->result = saved_result;
852 * hey, we are done. let's look to see what happened.
854 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
855 __FUNCTION__, scmd, rtn));
862 * scsi_eh_stu - send START_UNIT if needed
863 * @shost: scsi host being recovered.
864 * @eh_done_q: list_head for processed commands.
867 * If commands are failing due to not ready, initializing command required,
868 * try revalidating the device, which will end up sending a start unit.
870 static int scsi_eh_stu(struct Scsi_Host *shost,
871 struct list_head *work_q,
872 struct list_head *done_q)
874 struct scsi_cmnd *scmd, *stu_scmd, *next;
875 struct scsi_device *sdev;
877 shost_for_each_device(sdev, shost) {
879 list_for_each_entry(scmd, work_q, eh_entry)
880 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
881 scsi_check_sense(scmd) == FAILED ) {
889 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
890 " 0x%p\n", current->comm, sdev));
892 if (!scsi_eh_try_stu(stu_scmd)) {
893 if (!scsi_device_online(sdev) ||
894 !scsi_eh_tur(stu_scmd)) {
895 list_for_each_entry_safe(scmd, next,
897 if (scmd->device == sdev)
898 scsi_eh_finish_cmd(scmd, done_q);
902 SCSI_LOG_ERROR_RECOVERY(3,
903 printk("%s: START_UNIT failed to sdev:"
904 " 0x%p\n", current->comm, sdev));
908 return list_empty(work_q);
913 * scsi_eh_bus_device_reset - send bdr if needed
914 * @shost: scsi host being recovered.
915 * @eh_done_q: list_head for processed commands.
918 * Try a bus device reset. still, look to see whether we have multiple
919 * devices that are jammed or not - if we have multiple devices, it
920 * makes no sense to try bus_device_reset - we really would need to try
921 * a bus_reset instead.
923 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
924 struct list_head *work_q,
925 struct list_head *done_q)
927 struct scsi_cmnd *scmd, *bdr_scmd, *next;
928 struct scsi_device *sdev;
931 shost_for_each_device(sdev, shost) {
933 list_for_each_entry(scmd, work_q, eh_entry)
934 if (scmd->device == sdev) {
942 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
943 " 0x%p\n", current->comm,
945 rtn = scsi_try_bus_device_reset(bdr_scmd);
946 if (rtn == SUCCESS) {
947 if (!scsi_device_online(sdev) ||
948 !scsi_eh_tur(bdr_scmd)) {
949 list_for_each_entry_safe(scmd, next,
951 if (scmd->device == sdev)
952 scsi_eh_finish_cmd(scmd,
957 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
965 return list_empty(work_q);
969 * scsi_try_bus_reset - ask host to perform a bus reset
970 * @scmd: SCSI cmd to send bus reset.
972 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
977 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
980 if (!scmd->device->host->hostt->eh_bus_reset_handler)
983 rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
985 if (rtn == SUCCESS) {
986 if (!scmd->device->host->hostt->skip_settle_delay)
987 ssleep(BUS_RESET_SETTLE_TIME);
988 spin_lock_irqsave(scmd->device->host->host_lock, flags);
989 scsi_report_bus_reset(scmd->device->host,
991 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
998 * scsi_try_host_reset - ask host adapter to reset itself
999 * @scmd: SCSI cmd to send hsot reset.
1001 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1003 unsigned long flags;
1006 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1009 if (!scmd->device->host->hostt->eh_host_reset_handler)
1012 rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1014 if (rtn == SUCCESS) {
1015 if (!scmd->device->host->hostt->skip_settle_delay)
1016 ssleep(HOST_RESET_SETTLE_TIME);
1017 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1018 scsi_report_bus_reset(scmd->device->host,
1019 scmd_channel(scmd));
1020 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1027 * scsi_eh_bus_reset - send a bus reset
1028 * @shost: scsi host being recovered.
1029 * @eh_done_q: list_head for processed commands.
1031 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1032 struct list_head *work_q,
1033 struct list_head *done_q)
1035 struct scsi_cmnd *scmd, *chan_scmd, *next;
1036 unsigned int channel;
1040 * we really want to loop over the various channels, and do this on
1041 * a channel by channel basis. we should also check to see if any
1042 * of the failed commands are on soft_reset devices, and if so, skip
1046 for (channel = 0; channel <= shost->max_channel; channel++) {
1048 list_for_each_entry(scmd, work_q, eh_entry) {
1049 if (channel == scmd_channel(scmd)) {
1053 * FIXME add back in some support for
1054 * soft_reset devices.
1061 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1062 " %d\n", current->comm,
1064 rtn = scsi_try_bus_reset(chan_scmd);
1065 if (rtn == SUCCESS) {
1066 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1067 if (channel == scmd_channel(scmd))
1068 if (!scsi_device_online(scmd->device) ||
1070 scsi_eh_finish_cmd(scmd,
1074 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1075 " failed chan: %d\n",
1080 return list_empty(work_q);
1084 * scsi_eh_host_reset - send a host reset
1085 * @work_q: list_head for processed commands.
1086 * @done_q: list_head for processed commands.
1088 static int scsi_eh_host_reset(struct list_head *work_q,
1089 struct list_head *done_q)
1091 struct scsi_cmnd *scmd, *next;
1094 if (!list_empty(work_q)) {
1095 scmd = list_entry(work_q->next,
1096 struct scsi_cmnd, eh_entry);
1098 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1101 rtn = scsi_try_host_reset(scmd);
1102 if (rtn == SUCCESS) {
1103 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1104 if (!scsi_device_online(scmd->device) ||
1105 (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1107 scsi_eh_finish_cmd(scmd, done_q);
1110 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1115 return list_empty(work_q);
1119 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1120 * @work_q: list_head for processed commands.
1121 * @done_q: list_head for processed commands.
1124 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1125 struct list_head *done_q)
1127 struct scsi_cmnd *scmd, *next;
1129 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1130 sdev_printk(KERN_INFO, scmd->device,
1131 "scsi: Device offlined - not"
1132 " ready after error recovery\n");
1133 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1134 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1136 * FIXME: Handle lost cmds.
1139 scsi_eh_finish_cmd(scmd, done_q);
1145 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1146 * @scmd: SCSI cmd to examine.
1149 * This is *only* called when we are examining the status after sending
1150 * out the actual data command. any commands that are queued for error
1151 * recovery (e.g. test_unit_ready) do *not* come through here.
1153 * When this routine returns failed, it means the error handler thread
1154 * is woken. In cases where the error code indicates an error that
1155 * doesn't require the error handler read (i.e. we don't need to
1156 * abort/reset), this function should return SUCCESS.
1158 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1163 * if the device is offline, then we clearly just pass the result back
1164 * up to the top level.
1166 if (!scsi_device_online(scmd->device)) {
1167 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1174 * first check the host byte, to see if there is anything in there
1175 * that would indicate what we need to do.
1177 switch (host_byte(scmd->result)) {
1178 case DID_PASSTHROUGH:
1180 * no matter what, pass this through to the upper layer.
1181 * nuke this special code so that it looks like we are saying
1184 scmd->result &= 0xff00ffff;
1188 * looks good. drop through, and check the next byte.
1191 case DID_NO_CONNECT:
1192 case DID_BAD_TARGET:
1195 * note - this means that we just report the status back
1196 * to the top level driver, not that we actually think
1197 * that it indicates SUCCESS.
1201 * when the low level driver returns did_soft_error,
1202 * it is responsible for keeping an internal retry counter
1203 * in order to avoid endless loops (db)
1205 * actually this is a bug in this function here. we should
1206 * be mindful of the maximum number of retries specified
1207 * and not get stuck in a loop.
1209 case DID_SOFT_ERROR:
1215 return ADD_TO_MLQUEUE;
1218 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1219 status_byte(scmd->result) == RESERVATION_CONFLICT)
1221 * execute reservation conflict processing code
1232 * when we scan the bus, we get timeout messages for
1233 * these commands if there is no device available.
1234 * other hosts report did_no_connect for the same thing.
1236 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1237 scmd->cmnd[0] == INQUIRY)) {
1249 * next, check the message byte.
1251 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1255 * check the status byte to see if this indicates anything special.
1257 switch (status_byte(scmd->result)) {
1260 * the case of trying to send too many commands to a
1261 * tagged queueing device.
1265 * device can't talk to us at the moment. Should only
1266 * occur (SAM-3) when the task queue is empty, so will cause
1267 * the empty queue handling to trigger a stall in the
1270 return ADD_TO_MLQUEUE;
1272 case COMMAND_TERMINATED:
1275 case CHECK_CONDITION:
1276 rtn = scsi_check_sense(scmd);
1277 if (rtn == NEEDS_RETRY)
1279 /* if rtn == FAILED, we have no sense information;
1280 * returning FAILED will wake the error handler thread
1281 * to collect the sense and redo the decide
1284 case CONDITION_GOOD:
1285 case INTERMEDIATE_GOOD:
1286 case INTERMEDIATE_C_GOOD:
1289 * who knows? FIXME(eric)
1293 case RESERVATION_CONFLICT:
1294 sdev_printk(KERN_INFO, scmd->device,
1295 "reservation conflict\n");
1296 return SUCCESS; /* causes immediate i/o error */
1304 /* we requeue for retry because the error was retryable, and
1305 * the request was not marked fast fail. Note that above,
1306 * even if the request is marked fast fail, we still requeue
1307 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1308 if ((++scmd->retries) <= scmd->allowed
1309 && !blk_noretry_request(scmd->request)) {
1313 * no more retries - report this one back to upper level.
1320 * scsi_eh_lock_door - Prevent medium removal for the specified device
1321 * @sdev: SCSI device to prevent medium removal
1324 * We must be called from process context; scsi_allocate_request()
1328 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1329 * head of the devices request queue, and continue.
1332 * scsi_allocate_request() may sleep waiting for existing requests to
1333 * be processed. However, since we haven't kicked off any request
1334 * processing for this host, this may deadlock.
1336 * If scsi_allocate_request() fails for what ever reason, we
1337 * completely forget to lock the door.
1339 static void scsi_eh_lock_door(struct scsi_device *sdev)
1341 unsigned char cmnd[MAX_COMMAND_SIZE];
1343 cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1347 cmnd[4] = SCSI_REMOVAL_PREVENT;
1350 scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1351 5, NULL, NULL, GFP_KERNEL);
1356 * scsi_restart_operations - restart io operations to the specified host.
1357 * @shost: Host we are restarting.
1360 * When we entered the error handler, we blocked all further i/o to
1361 * this device. we need to 'reverse' this process.
1363 static void scsi_restart_operations(struct Scsi_Host *shost)
1365 struct scsi_device *sdev;
1366 unsigned long flags;
1369 * If the door was locked, we need to insert a door lock request
1370 * onto the head of the SCSI request queue for the device. There
1371 * is no point trying to lock the door of an off-line device.
1373 shost_for_each_device(sdev, shost) {
1374 if (scsi_device_online(sdev) && sdev->locked)
1375 scsi_eh_lock_door(sdev);
1379 * next free up anything directly waiting upon the host. this
1380 * will be requests for character device operations, and also for
1381 * ioctls to queued block devices.
1383 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1386 spin_lock_irqsave(shost->host_lock, flags);
1387 if (scsi_host_set_state(shost, SHOST_RUNNING))
1388 if (scsi_host_set_state(shost, SHOST_CANCEL))
1389 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1390 spin_unlock_irqrestore(shost->host_lock, flags);
1392 wake_up(&shost->host_wait);
1395 * finally we need to re-initiate requests that may be pending. we will
1396 * have had everything blocked while error handling is taking place, and
1397 * now that error recovery is done, we will need to ensure that these
1398 * requests are started.
1400 scsi_run_host_queues(shost);
1404 * scsi_eh_ready_devs - check device ready state and recover if not.
1405 * @shost: host to be recovered.
1406 * @eh_done_q: list_head for processed commands.
1409 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1410 struct list_head *work_q,
1411 struct list_head *done_q)
1413 if (!scsi_eh_stu(shost, work_q, done_q))
1414 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1415 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1416 if (!scsi_eh_host_reset(work_q, done_q))
1417 scsi_eh_offline_sdevs(work_q, done_q);
1421 * scsi_eh_flush_done_q - finish processed commands or retry them.
1422 * @done_q: list_head of processed commands.
1425 void scsi_eh_flush_done_q(struct list_head *done_q)
1427 struct scsi_cmnd *scmd, *next;
1429 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1430 list_del_init(&scmd->eh_entry);
1431 if (scsi_device_online(scmd->device) &&
1432 !blk_noretry_request(scmd->request) &&
1433 (++scmd->retries <= scmd->allowed)) {
1434 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1438 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1441 * If just we got sense for the device (called
1442 * scsi_eh_get_sense), scmd->result is already
1443 * set, do not set DRIVER_TIMEOUT.
1446 scmd->result |= (DRIVER_TIMEOUT << 24);
1447 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1449 current->comm, scmd));
1450 scsi_finish_command(scmd);
1454 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1457 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1458 * @shost: Host to unjam.
1461 * When we come in here, we *know* that all commands on the bus have
1462 * either completed, failed or timed out. we also know that no further
1463 * commands are being sent to the host, so things are relatively quiet
1464 * and we have freedom to fiddle with things as we wish.
1466 * This is only the *default* implementation. it is possible for
1467 * individual drivers to supply their own version of this function, and
1468 * if the maintainer wishes to do this, it is strongly suggested that
1469 * this function be taken as a template and modified. this function
1470 * was designed to correctly handle problems for about 95% of the
1471 * different cases out there, and it should always provide at least a
1472 * reasonable amount of error recovery.
1474 * Any command marked 'failed' or 'timeout' must eventually have
1475 * scsi_finish_cmd() called for it. we do all of the retry stuff
1476 * here, so when we restart the host after we return it should have an
1479 static void scsi_unjam_host(struct Scsi_Host *shost)
1481 unsigned long flags;
1482 LIST_HEAD(eh_work_q);
1483 LIST_HEAD(eh_done_q);
1485 spin_lock_irqsave(shost->host_lock, flags);
1486 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1487 spin_unlock_irqrestore(shost->host_lock, flags);
1489 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1491 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1492 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1493 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1495 scsi_eh_flush_done_q(&eh_done_q);
1499 * scsi_error_handler - SCSI error handler thread
1500 * @data: Host for which we are running.
1503 * This is the main error handling loop. This is run as a kernel thread
1504 * for every SCSI host and handles all error handling activity.
1506 int scsi_error_handler(void *data)
1508 struct Scsi_Host *shost = data;
1510 current->flags |= PF_NOFREEZE;
1513 * We use TASK_INTERRUPTIBLE so that the thread is not
1514 * counted against the load average as a running process.
1515 * We never actually get interrupted because kthread_run
1516 * disables singal delivery for the created thread.
1518 set_current_state(TASK_INTERRUPTIBLE);
1519 while (!kthread_should_stop()) {
1520 if (shost->host_failed == 0 ||
1521 shost->host_failed != shost->host_busy) {
1522 SCSI_LOG_ERROR_RECOVERY(1,
1523 printk("Error handler scsi_eh_%d sleeping\n",
1526 set_current_state(TASK_INTERRUPTIBLE);
1530 __set_current_state(TASK_RUNNING);
1531 SCSI_LOG_ERROR_RECOVERY(1,
1532 printk("Error handler scsi_eh_%d waking up\n",
1536 * We have a host that is failing for some reason. Figure out
1537 * what we need to do to get it up and online again (if we can).
1538 * If we fail, we end up taking the thing offline.
1540 if (shost->transportt->eh_strategy_handler)
1541 shost->transportt->eh_strategy_handler(shost);
1543 scsi_unjam_host(shost);
1546 * Note - if the above fails completely, the action is to take
1547 * individual devices offline and flush the queue of any
1548 * outstanding requests that may have been pending. When we
1549 * restart, we restart any I/O to any other devices on the bus
1550 * which are still online.
1552 scsi_restart_operations(shost);
1553 set_current_state(TASK_INTERRUPTIBLE);
1555 __set_current_state(TASK_RUNNING);
1557 SCSI_LOG_ERROR_RECOVERY(1,
1558 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1559 shost->ehandler = NULL;
1564 * Function: scsi_report_bus_reset()
1566 * Purpose: Utility function used by low-level drivers to report that
1567 * they have observed a bus reset on the bus being handled.
1569 * Arguments: shost - Host in question
1570 * channel - channel on which reset was observed.
1574 * Lock status: Host lock must be held.
1576 * Notes: This only needs to be called if the reset is one which
1577 * originates from an unknown location. Resets originated
1578 * by the mid-level itself don't need to call this, but there
1579 * should be no harm.
1581 * The main purpose of this is to make sure that a CHECK_CONDITION
1582 * is properly treated.
1584 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1586 struct scsi_device *sdev;
1588 __shost_for_each_device(sdev, shost) {
1589 if (channel == sdev_channel(sdev)) {
1590 sdev->was_reset = 1;
1591 sdev->expecting_cc_ua = 1;
1595 EXPORT_SYMBOL(scsi_report_bus_reset);
1598 * Function: scsi_report_device_reset()
1600 * Purpose: Utility function used by low-level drivers to report that
1601 * they have observed a device reset on the device being handled.
1603 * Arguments: shost - Host in question
1604 * channel - channel on which reset was observed
1605 * target - target on which reset was observed
1609 * Lock status: Host lock must be held
1611 * Notes: This only needs to be called if the reset is one which
1612 * originates from an unknown location. Resets originated
1613 * by the mid-level itself don't need to call this, but there
1614 * should be no harm.
1616 * The main purpose of this is to make sure that a CHECK_CONDITION
1617 * is properly treated.
1619 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1621 struct scsi_device *sdev;
1623 __shost_for_each_device(sdev, shost) {
1624 if (channel == sdev_channel(sdev) &&
1625 target == sdev_id(sdev)) {
1626 sdev->was_reset = 1;
1627 sdev->expecting_cc_ua = 1;
1631 EXPORT_SYMBOL(scsi_report_device_reset);
1634 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1639 * Function: scsi_reset_provider
1641 * Purpose: Send requested reset to a bus or device at any phase.
1643 * Arguments: device - device to send reset to
1644 * flag - reset type (see scsi.h)
1646 * Returns: SUCCESS/FAILURE.
1648 * Notes: This is used by the SCSI Generic driver to provide
1649 * Bus/Device reset capability.
1652 scsi_reset_provider(struct scsi_device *dev, int flag)
1654 struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1658 scmd->request = &req;
1659 memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1660 scmd->request->rq_status = RQ_SCSI_BUSY;
1662 memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1664 scmd->scsi_done = scsi_reset_provider_done_command;
1666 scmd->buffer = NULL;
1668 scmd->request_buffer = NULL;
1669 scmd->request_bufflen = 0;
1673 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
1674 scmd->sc_request = NULL;
1675 scmd->sc_magic = SCSI_CMND_MAGIC;
1677 init_timer(&scmd->eh_timeout);
1680 * Sometimes the command can get back into the timer chain,
1681 * so use the pid as an identifier.
1686 case SCSI_TRY_RESET_DEVICE:
1687 rtn = scsi_try_bus_device_reset(scmd);
1691 case SCSI_TRY_RESET_BUS:
1692 rtn = scsi_try_bus_reset(scmd);
1696 case SCSI_TRY_RESET_HOST:
1697 rtn = scsi_try_host_reset(scmd);
1703 scsi_next_command(scmd);
1706 EXPORT_SYMBOL(scsi_reset_provider);
1709 * scsi_normalize_sense - normalize main elements from either fixed or
1710 * descriptor sense data format into a common format.
1712 * @sense_buffer: byte array containing sense data returned by device
1713 * @sb_len: number of valid bytes in sense_buffer
1714 * @sshdr: pointer to instance of structure that common
1715 * elements are written to.
1718 * The "main elements" from sense data are: response_code, sense_key,
1719 * asc, ascq and additional_length (only for descriptor format).
1721 * Typically this function can be called after a device has
1722 * responded to a SCSI command with the CHECK_CONDITION status.
1725 * 1 if valid sense data information found, else 0;
1727 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1728 struct scsi_sense_hdr *sshdr)
1730 if (!sense_buffer || !sb_len)
1733 memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1735 sshdr->response_code = (sense_buffer[0] & 0x7f);
1737 if (!scsi_sense_valid(sshdr))
1740 if (sshdr->response_code >= 0x72) {
1745 sshdr->sense_key = (sense_buffer[1] & 0xf);
1747 sshdr->asc = sense_buffer[2];
1749 sshdr->ascq = sense_buffer[3];
1751 sshdr->additional_length = sense_buffer[7];
1757 sshdr->sense_key = (sense_buffer[2] & 0xf);
1759 sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1760 sb_len : (sense_buffer[7] + 8);
1762 sshdr->asc = sense_buffer[12];
1764 sshdr->ascq = sense_buffer[13];
1770 EXPORT_SYMBOL(scsi_normalize_sense);
1772 int scsi_request_normalize_sense(struct scsi_request *sreq,
1773 struct scsi_sense_hdr *sshdr)
1775 return scsi_normalize_sense(sreq->sr_sense_buffer,
1776 sizeof(sreq->sr_sense_buffer), sshdr);
1778 EXPORT_SYMBOL(scsi_request_normalize_sense);
1780 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1781 struct scsi_sense_hdr *sshdr)
1783 return scsi_normalize_sense(cmd->sense_buffer,
1784 sizeof(cmd->sense_buffer), sshdr);
1786 EXPORT_SYMBOL(scsi_command_normalize_sense);
1789 * scsi_sense_desc_find - search for a given descriptor type in
1790 * descriptor sense data format.
1792 * @sense_buffer: byte array of descriptor format sense data
1793 * @sb_len: number of valid bytes in sense_buffer
1794 * @desc_type: value of descriptor type to find
1795 * (e.g. 0 -> information)
1798 * only valid when sense data is in descriptor format
1801 * pointer to start of (first) descriptor if found else NULL
1803 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1806 int add_sen_len, add_len, desc_len, k;
1809 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1811 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1813 add_sen_len = (add_sen_len < (sb_len - 8)) ?
1814 add_sen_len : (sb_len - 8);
1815 descp = &sense_buffer[8];
1816 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1818 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1819 desc_len = add_len + 2;
1820 if (descp[0] == desc_type)
1822 if (add_len < 0) // short descriptor ??
1827 EXPORT_SYMBOL(scsi_sense_desc_find);
1830 * scsi_get_sense_info_fld - attempts to get information field from
1831 * sense data (either fixed or descriptor format)
1833 * @sense_buffer: byte array of sense data
1834 * @sb_len: number of valid bytes in sense_buffer
1835 * @info_out: pointer to 64 integer where 8 or 4 byte information
1836 * field will be placed if found.
1839 * 1 if information field found, 0 if not found.
1841 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1850 switch (sense_buffer[0] & 0x7f) {
1853 if (sense_buffer[0] & 0x80) {
1854 *info_out = (sense_buffer[3] << 24) +
1855 (sense_buffer[4] << 16) +
1856 (sense_buffer[5] << 8) + sense_buffer[6];
1862 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1864 if (ucp && (0xa == ucp[1])) {
1866 for (j = 0; j < 8; ++j) {
1879 EXPORT_SYMBOL(scsi_get_sense_info_fld);