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_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_eh.h>
33 #include <scsi/scsi_transport.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_ioctl.h>
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_schedule_eh - schedule EH for SCSI host
62 * @shost: SCSI host to invoke error handling on.
64 * Schedule SCSI EH without scmd.
66 void scsi_schedule_eh(struct Scsi_Host *shost)
70 spin_lock_irqsave(shost->host_lock, flags);
72 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
73 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
74 shost->host_eh_scheduled++;
75 scsi_eh_wakeup(shost);
78 spin_unlock_irqrestore(shost->host_lock, flags);
80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
83 * scsi_eh_scmd_add - add scsi cmd to error handling.
84 * @scmd: scmd to run eh on.
85 * @eh_flag: optional SCSI_EH flag.
90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
92 struct Scsi_Host *shost = scmd->device->host;
99 spin_lock_irqsave(shost->host_lock, flags);
100 if (scsi_host_set_state(shost, SHOST_RECOVERY))
101 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
105 scmd->eh_eflags |= eh_flag;
106 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
107 shost->host_failed++;
108 scsi_eh_wakeup(shost);
110 spin_unlock_irqrestore(shost->host_lock, flags);
115 * scsi_add_timer - Start timeout timer for a single scsi command.
116 * @scmd: scsi command that is about to start running.
117 * @timeout: amount of time to allow this command to run.
118 * @complete: timeout function to call if timer isn't canceled.
121 * This should be turned into an inline function. Each scsi command
122 * has its own timer, and as it is added to the queue, we set up the
123 * timer. When the command completes, we cancel the timer.
125 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
126 void (*complete)(struct scsi_cmnd *))
130 * If the clock was already running for this command, then
131 * first delete the timer. The timer handling code gets rather
132 * confused if we don't do this.
134 if (scmd->eh_timeout.function)
135 del_timer(&scmd->eh_timeout);
137 scmd->eh_timeout.data = (unsigned long)scmd;
138 scmd->eh_timeout.expires = jiffies + timeout;
139 scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
141 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
142 " %d, (%p)\n", __FUNCTION__,
143 scmd, timeout, complete));
145 add_timer(&scmd->eh_timeout);
149 * scsi_delete_timer - Delete/cancel timer for a given function.
150 * @scmd: Cmd that we are canceling timer for
153 * This should be turned into an inline function.
156 * 1 if we were able to detach the timer. 0 if we blew it, and the
157 * timer function has already started to run.
159 int scsi_delete_timer(struct scsi_cmnd *scmd)
163 rtn = del_timer(&scmd->eh_timeout);
165 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
166 " rtn: %d\n", __FUNCTION__,
169 scmd->eh_timeout.data = (unsigned long)NULL;
170 scmd->eh_timeout.function = NULL;
176 * scsi_times_out - Timeout function for normal scsi commands.
177 * @scmd: Cmd that is timing out.
180 * We do not need to lock this. There is the potential for a race
181 * only in that the normal completion handling might run, but if the
182 * normal completion function determines that the timer has already
183 * fired, then it mustn't do anything.
185 void scsi_times_out(struct scsi_cmnd *scmd)
187 scsi_log_completion(scmd, TIMEOUT_ERROR);
189 if (scmd->device->host->transportt->eh_timed_out)
190 switch (scmd->device->host->transportt->eh_timed_out(scmd)) {
195 scsi_add_timer(scmd, scmd->timeout_per_command,
202 if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
203 scmd->result |= DID_TIME_OUT << 16;
209 * scsi_block_when_processing_errors - Prevent cmds from being queued.
210 * @sdev: Device on which we are performing recovery.
213 * We block until the host is out of error recovery, and then check to
214 * see whether the host or the device is offline.
217 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
219 int scsi_block_when_processing_errors(struct scsi_device *sdev)
223 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
225 online = scsi_device_online(sdev);
227 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
232 EXPORT_SYMBOL(scsi_block_when_processing_errors);
234 #ifdef CONFIG_SCSI_LOGGING
236 * scsi_eh_prt_fail_stats - Log info on failures.
237 * @shost: scsi host being recovered.
238 * @work_q: Queue of scsi cmds to process.
240 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
241 struct list_head *work_q)
243 struct scsi_cmnd *scmd;
244 struct scsi_device *sdev;
245 int total_failures = 0;
248 int devices_failed = 0;
250 shost_for_each_device(sdev, shost) {
251 list_for_each_entry(scmd, work_q, eh_entry) {
252 if (scmd->device == sdev) {
254 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
261 if (cmd_cancel || cmd_failed) {
262 SCSI_LOG_ERROR_RECOVERY(3,
263 sdev_printk(KERN_INFO, sdev,
264 "%s: cmds failed: %d, cancel: %d\n",
265 __FUNCTION__, cmd_failed,
273 SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
274 " devices require eh work\n",
275 total_failures, devices_failed));
280 * scsi_check_sense - Examine scsi cmd sense
281 * @scmd: Cmd to have sense checked.
284 * SUCCESS or FAILED or NEEDS_RETRY
287 * When a deferred error is detected the current command has
288 * not been executed and needs retrying.
290 static int scsi_check_sense(struct scsi_cmnd *scmd)
292 struct scsi_sense_hdr sshdr;
294 if (! scsi_command_normalize_sense(scmd, &sshdr))
295 return FAILED; /* no valid sense data */
297 if (scsi_sense_is_deferred(&sshdr))
301 * Previous logic looked for FILEMARK, EOM or ILI which are
302 * mainly associated with tapes and returned SUCCESS.
304 if (sshdr.response_code == 0x70) {
306 if (scmd->sense_buffer[2] & 0xe0)
310 * descriptor format: look for "stream commands sense data
311 * descriptor" (see SSC-3). Assume single sense data
312 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
314 if ((sshdr.additional_length > 3) &&
315 (scmd->sense_buffer[8] == 0x4) &&
316 (scmd->sense_buffer[11] & 0xe0))
320 switch (sshdr.sense_key) {
323 case RECOVERED_ERROR:
324 return /* soft_error */ SUCCESS;
326 case ABORTED_COMMAND:
331 * if we are expecting a cc/ua because of a bus reset that we
332 * performed, treat this just as a retry. otherwise this is
333 * information that we should pass up to the upper-level driver
334 * so that we can deal with it there.
336 if (scmd->device->expecting_cc_ua) {
337 scmd->device->expecting_cc_ua = 0;
341 * if the device is in the process of becoming ready, we
344 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
347 * if the device is not started, we need to wake
348 * the error handler to start the motor
350 if (scmd->device->allow_restart &&
351 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
355 /* these three are not supported */
357 case VOLUME_OVERFLOW:
365 if (scmd->device->retry_hwerror)
370 case ILLEGAL_REQUEST:
379 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
380 * @scmd: SCSI cmd to examine.
383 * This is *only* called when we are examining the status of commands
384 * queued during error recovery. the main difference here is that we
385 * don't allow for the possibility of retries here, and we are a lot
386 * more restrictive about what we consider acceptable.
388 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
391 * first check the host byte, to see if there is anything in there
392 * that would indicate what we need to do.
394 if (host_byte(scmd->result) == DID_RESET) {
396 * rats. we are already in the error handler, so we now
397 * get to try and figure out what to do next. if the sense
398 * is valid, we have a pretty good idea of what to do.
399 * if not, we mark it as FAILED.
401 return scsi_check_sense(scmd);
403 if (host_byte(scmd->result) != DID_OK)
407 * next, check the message byte.
409 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
413 * now, check the status byte to see if this indicates
416 switch (status_byte(scmd->result)) {
418 case COMMAND_TERMINATED:
420 case CHECK_CONDITION:
421 return scsi_check_sense(scmd);
423 case INTERMEDIATE_GOOD:
424 case INTERMEDIATE_C_GOOD:
426 * who knows? FIXME(eric)
431 case RESERVATION_CONFLICT:
439 * scsi_eh_done - Completion function for error handling.
440 * @scmd: Cmd that is done.
442 static void scsi_eh_done(struct scsi_cmnd *scmd)
444 struct completion *eh_action;
446 SCSI_LOG_ERROR_RECOVERY(3,
447 printk("%s scmd: %p result: %x\n",
448 __FUNCTION__, scmd, scmd->result));
450 eh_action = scmd->device->host->eh_action;
456 * scsi_send_eh_cmnd - send a cmd to a device as part of error recovery.
457 * @scmd: SCSI Cmd to send.
458 * @timeout: Timeout for cmd.
461 * SUCCESS or FAILED or NEEDS_RETRY
463 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
465 struct scsi_device *sdev = scmd->device;
466 struct Scsi_Host *shost = sdev->host;
467 DECLARE_COMPLETION(done);
468 unsigned long timeleft;
472 if (sdev->scsi_level <= SCSI_2)
473 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
474 (sdev->lun << 5 & 0xe0);
476 shost->eh_action = &done;
478 spin_lock_irqsave(shost->host_lock, flags);
480 shost->hostt->queuecommand(scmd, scsi_eh_done);
481 spin_unlock_irqrestore(shost->host_lock, flags);
483 timeleft = wait_for_completion_timeout(&done, timeout);
485 shost->eh_action = NULL;
487 scsi_log_completion(scmd, SUCCESS);
489 SCSI_LOG_ERROR_RECOVERY(3,
490 printk("%s: scmd: %p, timeleft: %ld\n",
491 __FUNCTION__, scmd, timeleft));
494 * If there is time left scsi_eh_done got called, and we will
495 * examine the actual status codes to see whether the command
496 * actually did complete normally, else tell the host to forget
497 * about this command.
500 rtn = scsi_eh_completed_normally(scmd);
501 SCSI_LOG_ERROR_RECOVERY(3,
502 printk("%s: scsi_eh_completed_normally %x\n",
516 * FIXME(eric) - we are not tracking whether we could
517 * abort a timed out command or not. not sure how
518 * we should treat them differently anyways.
520 if (shost->hostt->eh_abort_handler)
521 shost->hostt->eh_abort_handler(scmd);
529 * scsi_request_sense - Request sense data from a particular target.
530 * @scmd: SCSI cmd for request sense.
533 * Some hosts automatically obtain this information, others require
534 * that we obtain it on our own. This function will *not* return until
535 * the command either times out, or it completes.
537 static int scsi_request_sense(struct scsi_cmnd *scmd)
539 static unsigned char generic_sense[6] =
540 {REQUEST_SENSE, 0, 0, 0, 252, 0};
541 unsigned char *scsi_result;
545 memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
547 scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
550 if (unlikely(!scsi_result)) {
551 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
557 * zero the sense buffer. some host adapters automatically always
558 * request sense, so it is not a good idea that
559 * scmd->request_buffer and scmd->sense_buffer point to the same
560 * address (db). 0 is not a valid sense code.
562 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
563 memset(scsi_result, 0, 252);
565 saved_result = scmd->result;
566 scmd->request_buffer = scsi_result;
567 scmd->request_bufflen = 252;
569 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
570 scmd->sc_data_direction = DMA_FROM_DEVICE;
573 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
575 /* last chance to have valid sense data */
576 if(!SCSI_SENSE_VALID(scmd)) {
577 memcpy(scmd->sense_buffer, scmd->request_buffer,
578 sizeof(scmd->sense_buffer));
584 * when we eventually call scsi_finish, we really wish to complete
585 * the original request, so let's restore the original data. (db)
587 scsi_setup_cmd_retry(scmd);
588 scmd->result = saved_result;
593 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
594 * @scmd: Original SCSI cmd that eh has finished.
595 * @done_q: Queue for processed commands.
598 * We don't want to use the normal command completion while we are are
599 * still handling errors - it may cause other commands to be queued,
600 * and that would disturb what we are doing. thus we really want to
601 * keep a list of pending commands for final completion, and once we
602 * are ready to leave error handling we handle completion for real.
604 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
606 scmd->device->host->host_failed--;
610 * set this back so that the upper level can correctly free up
613 scsi_setup_cmd_retry(scmd);
614 list_move_tail(&scmd->eh_entry, done_q);
616 EXPORT_SYMBOL(scsi_eh_finish_cmd);
619 * scsi_eh_get_sense - Get device sense data.
620 * @work_q: Queue of commands to process.
621 * @done_q: Queue of proccessed commands..
624 * See if we need to request sense information. if so, then get it
625 * now, so we have a better idea of what to do.
628 * This has the unfortunate side effect that if a shost adapter does
629 * not automatically request sense information, that we end up shutting
630 * it down before we request it.
632 * All drivers should request sense information internally these days,
633 * so for now all I have to say is tough noogies if you end up in here.
635 * XXX: Long term this code should go away, but that needs an audit of
638 static int scsi_eh_get_sense(struct list_head *work_q,
639 struct list_head *done_q)
641 struct scsi_cmnd *scmd, *next;
644 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
645 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
646 SCSI_SENSE_VALID(scmd))
649 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
650 "%s: requesting sense\n",
652 rtn = scsi_request_sense(scmd);
656 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
657 " result %x\n", scmd,
659 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
661 rtn = scsi_decide_disposition(scmd);
664 * if the result was normal, then just pass it along to the
668 /* we don't want this command reissued, just
669 * finished with the sense data, so set
670 * retries to the max allowed to ensure it
671 * won't get reissued */
672 scmd->retries = scmd->allowed;
673 else if (rtn != NEEDS_RETRY)
676 scsi_eh_finish_cmd(scmd, done_q);
679 return list_empty(work_q);
683 * scsi_try_to_abort_cmd - Ask host to abort a running command.
684 * @scmd: SCSI cmd to abort from Lower Level.
687 * This function will not return until the user's completion function
688 * has been called. there is no timeout on this operation. if the
689 * author of the low-level driver wishes this operation to be timed,
690 * they can provide this facility themselves. helper functions in
691 * scsi_error.c can be supplied to make this easier to do.
693 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
695 if (!scmd->device->host->hostt->eh_abort_handler)
699 * scsi_done was called just after the command timed out and before
700 * we had a chance to process it. (db)
702 if (scmd->serial_number == 0)
704 return scmd->device->host->hostt->eh_abort_handler(scmd);
708 * scsi_eh_tur - Send TUR to device.
709 * @scmd: Scsi cmd to send TUR
712 * 0 - Device is ready. 1 - Device NOT ready.
714 static int scsi_eh_tur(struct scsi_cmnd *scmd)
716 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
717 int retry_cnt = 1, rtn;
721 memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
724 * zero the sense buffer. the scsi spec mandates that any
725 * untransferred sense data should be interpreted as being zero.
727 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
729 saved_result = scmd->result;
730 scmd->request_buffer = NULL;
731 scmd->request_bufflen = 0;
733 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
735 scmd->sc_data_direction = DMA_NONE;
737 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
740 * when we eventually call scsi_finish, we really wish to complete
741 * the original request, so let's restore the original data. (db)
743 scsi_setup_cmd_retry(scmd);
744 scmd->result = saved_result;
747 * hey, we are done. let's look to see what happened.
749 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
750 __FUNCTION__, scmd, rtn));
753 else if (rtn == NEEDS_RETRY) {
762 * scsi_eh_abort_cmds - abort canceled commands.
763 * @shost: scsi host being recovered.
764 * @eh_done_q: list_head for processed commands.
767 * Try and see whether or not it makes sense to try and abort the
768 * running command. this only works out to be the case if we have one
769 * command that has timed out. if the command simply failed, it makes
770 * no sense to try and abort the command, since as far as the shost
771 * adapter is concerned, it isn't running.
773 static int scsi_eh_abort_cmds(struct list_head *work_q,
774 struct list_head *done_q)
776 struct scsi_cmnd *scmd, *next;
779 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
780 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
782 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
783 "0x%p\n", current->comm,
785 rtn = scsi_try_to_abort_cmd(scmd);
786 if (rtn == SUCCESS) {
787 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
788 if (!scsi_device_online(scmd->device) ||
789 !scsi_eh_tur(scmd)) {
790 scsi_eh_finish_cmd(scmd, done_q);
794 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
801 return list_empty(work_q);
805 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
806 * @scmd: SCSI cmd used to send BDR
809 * There is no timeout for this operation. if this operation is
810 * unreliable for a given host, then the host itself needs to put a
811 * timer on it, and set the host back to a consistent state prior to
814 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
818 if (!scmd->device->host->hostt->eh_device_reset_handler)
821 rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
822 if (rtn == SUCCESS) {
823 scmd->device->was_reset = 1;
824 scmd->device->expecting_cc_ua = 1;
831 * scsi_eh_try_stu - Send START_UNIT to device.
832 * @scmd: Scsi cmd to send START_UNIT
835 * 0 - Device is ready. 1 - Device NOT ready.
837 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
839 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
843 if (!scmd->device->allow_restart)
846 memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
849 * zero the sense buffer. the scsi spec mandates that any
850 * untransferred sense data should be interpreted as being zero.
852 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
854 saved_result = scmd->result;
855 scmd->request_buffer = NULL;
856 scmd->request_bufflen = 0;
858 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
860 scmd->sc_data_direction = DMA_NONE;
862 rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
865 * when we eventually call scsi_finish, we really wish to complete
866 * the original request, so let's restore the original data. (db)
868 scsi_setup_cmd_retry(scmd);
869 scmd->result = saved_result;
872 * hey, we are done. let's look to see what happened.
874 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
875 __FUNCTION__, scmd, rtn));
882 * scsi_eh_stu - send START_UNIT if needed
883 * @shost: scsi host being recovered.
884 * @eh_done_q: list_head for processed commands.
887 * If commands are failing due to not ready, initializing command required,
888 * try revalidating the device, which will end up sending a start unit.
890 static int scsi_eh_stu(struct Scsi_Host *shost,
891 struct list_head *work_q,
892 struct list_head *done_q)
894 struct scsi_cmnd *scmd, *stu_scmd, *next;
895 struct scsi_device *sdev;
897 shost_for_each_device(sdev, shost) {
899 list_for_each_entry(scmd, work_q, eh_entry)
900 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
901 scsi_check_sense(scmd) == FAILED ) {
909 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
910 " 0x%p\n", current->comm, sdev));
912 if (!scsi_eh_try_stu(stu_scmd)) {
913 if (!scsi_device_online(sdev) ||
914 !scsi_eh_tur(stu_scmd)) {
915 list_for_each_entry_safe(scmd, next,
917 if (scmd->device == sdev)
918 scsi_eh_finish_cmd(scmd, done_q);
922 SCSI_LOG_ERROR_RECOVERY(3,
923 printk("%s: START_UNIT failed to sdev:"
924 " 0x%p\n", current->comm, sdev));
928 return list_empty(work_q);
933 * scsi_eh_bus_device_reset - send bdr if needed
934 * @shost: scsi host being recovered.
935 * @eh_done_q: list_head for processed commands.
938 * Try a bus device reset. still, look to see whether we have multiple
939 * devices that are jammed or not - if we have multiple devices, it
940 * makes no sense to try bus_device_reset - we really would need to try
941 * a bus_reset instead.
943 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
944 struct list_head *work_q,
945 struct list_head *done_q)
947 struct scsi_cmnd *scmd, *bdr_scmd, *next;
948 struct scsi_device *sdev;
951 shost_for_each_device(sdev, shost) {
953 list_for_each_entry(scmd, work_q, eh_entry)
954 if (scmd->device == sdev) {
962 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
963 " 0x%p\n", current->comm,
965 rtn = scsi_try_bus_device_reset(bdr_scmd);
966 if (rtn == SUCCESS) {
967 if (!scsi_device_online(sdev) ||
968 !scsi_eh_tur(bdr_scmd)) {
969 list_for_each_entry_safe(scmd, next,
971 if (scmd->device == sdev)
972 scsi_eh_finish_cmd(scmd,
977 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
985 return list_empty(work_q);
989 * scsi_try_bus_reset - ask host to perform a bus reset
990 * @scmd: SCSI cmd to send bus reset.
992 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
997 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1000 if (!scmd->device->host->hostt->eh_bus_reset_handler)
1003 rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1005 if (rtn == SUCCESS) {
1006 if (!scmd->device->host->hostt->skip_settle_delay)
1007 ssleep(BUS_RESET_SETTLE_TIME);
1008 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1009 scsi_report_bus_reset(scmd->device->host,
1010 scmd_channel(scmd));
1011 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1018 * scsi_try_host_reset - ask host adapter to reset itself
1019 * @scmd: SCSI cmd to send hsot reset.
1021 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1023 unsigned long flags;
1026 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1029 if (!scmd->device->host->hostt->eh_host_reset_handler)
1032 rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1034 if (rtn == SUCCESS) {
1035 if (!scmd->device->host->hostt->skip_settle_delay)
1036 ssleep(HOST_RESET_SETTLE_TIME);
1037 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1038 scsi_report_bus_reset(scmd->device->host,
1039 scmd_channel(scmd));
1040 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1047 * scsi_eh_bus_reset - send a bus reset
1048 * @shost: scsi host being recovered.
1049 * @eh_done_q: list_head for processed commands.
1051 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1052 struct list_head *work_q,
1053 struct list_head *done_q)
1055 struct scsi_cmnd *scmd, *chan_scmd, *next;
1056 unsigned int channel;
1060 * we really want to loop over the various channels, and do this on
1061 * a channel by channel basis. we should also check to see if any
1062 * of the failed commands are on soft_reset devices, and if so, skip
1066 for (channel = 0; channel <= shost->max_channel; channel++) {
1068 list_for_each_entry(scmd, work_q, eh_entry) {
1069 if (channel == scmd_channel(scmd)) {
1073 * FIXME add back in some support for
1074 * soft_reset devices.
1081 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1082 " %d\n", current->comm,
1084 rtn = scsi_try_bus_reset(chan_scmd);
1085 if (rtn == SUCCESS) {
1086 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1087 if (channel == scmd_channel(scmd))
1088 if (!scsi_device_online(scmd->device) ||
1090 scsi_eh_finish_cmd(scmd,
1094 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1095 " failed chan: %d\n",
1100 return list_empty(work_q);
1104 * scsi_eh_host_reset - send a host reset
1105 * @work_q: list_head for processed commands.
1106 * @done_q: list_head for processed commands.
1108 static int scsi_eh_host_reset(struct list_head *work_q,
1109 struct list_head *done_q)
1111 struct scsi_cmnd *scmd, *next;
1114 if (!list_empty(work_q)) {
1115 scmd = list_entry(work_q->next,
1116 struct scsi_cmnd, eh_entry);
1118 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1121 rtn = scsi_try_host_reset(scmd);
1122 if (rtn == SUCCESS) {
1123 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1124 if (!scsi_device_online(scmd->device) ||
1125 (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1127 scsi_eh_finish_cmd(scmd, done_q);
1130 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1135 return list_empty(work_q);
1139 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1140 * @work_q: list_head for processed commands.
1141 * @done_q: list_head for processed commands.
1144 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1145 struct list_head *done_q)
1147 struct scsi_cmnd *scmd, *next;
1149 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1150 sdev_printk(KERN_INFO, scmd->device,
1151 "scsi: Device offlined - not"
1152 " ready after error recovery\n");
1153 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1154 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1156 * FIXME: Handle lost cmds.
1159 scsi_eh_finish_cmd(scmd, done_q);
1165 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1166 * @scmd: SCSI cmd to examine.
1169 * This is *only* called when we are examining the status after sending
1170 * out the actual data command. any commands that are queued for error
1171 * recovery (e.g. test_unit_ready) do *not* come through here.
1173 * When this routine returns failed, it means the error handler thread
1174 * is woken. In cases where the error code indicates an error that
1175 * doesn't require the error handler read (i.e. we don't need to
1176 * abort/reset), this function should return SUCCESS.
1178 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1183 * if the device is offline, then we clearly just pass the result back
1184 * up to the top level.
1186 if (!scsi_device_online(scmd->device)) {
1187 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1194 * first check the host byte, to see if there is anything in there
1195 * that would indicate what we need to do.
1197 switch (host_byte(scmd->result)) {
1198 case DID_PASSTHROUGH:
1200 * no matter what, pass this through to the upper layer.
1201 * nuke this special code so that it looks like we are saying
1204 scmd->result &= 0xff00ffff;
1208 * looks good. drop through, and check the next byte.
1211 case DID_NO_CONNECT:
1212 case DID_BAD_TARGET:
1215 * note - this means that we just report the status back
1216 * to the top level driver, not that we actually think
1217 * that it indicates SUCCESS.
1221 * when the low level driver returns did_soft_error,
1222 * it is responsible for keeping an internal retry counter
1223 * in order to avoid endless loops (db)
1225 * actually this is a bug in this function here. we should
1226 * be mindful of the maximum number of retries specified
1227 * and not get stuck in a loop.
1229 case DID_SOFT_ERROR:
1235 return ADD_TO_MLQUEUE;
1238 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1239 status_byte(scmd->result) == RESERVATION_CONFLICT)
1241 * execute reservation conflict processing code
1252 * when we scan the bus, we get timeout messages for
1253 * these commands if there is no device available.
1254 * other hosts report did_no_connect for the same thing.
1256 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1257 scmd->cmnd[0] == INQUIRY)) {
1269 * next, check the message byte.
1271 if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1275 * check the status byte to see if this indicates anything special.
1277 switch (status_byte(scmd->result)) {
1280 * the case of trying to send too many commands to a
1281 * tagged queueing device.
1285 * device can't talk to us at the moment. Should only
1286 * occur (SAM-3) when the task queue is empty, so will cause
1287 * the empty queue handling to trigger a stall in the
1290 return ADD_TO_MLQUEUE;
1292 case COMMAND_TERMINATED:
1295 case CHECK_CONDITION:
1296 rtn = scsi_check_sense(scmd);
1297 if (rtn == NEEDS_RETRY)
1299 /* if rtn == FAILED, we have no sense information;
1300 * returning FAILED will wake the error handler thread
1301 * to collect the sense and redo the decide
1304 case CONDITION_GOOD:
1305 case INTERMEDIATE_GOOD:
1306 case INTERMEDIATE_C_GOOD:
1309 * who knows? FIXME(eric)
1313 case RESERVATION_CONFLICT:
1314 sdev_printk(KERN_INFO, scmd->device,
1315 "reservation conflict\n");
1316 return SUCCESS; /* causes immediate i/o error */
1324 /* we requeue for retry because the error was retryable, and
1325 * the request was not marked fast fail. Note that above,
1326 * even if the request is marked fast fail, we still requeue
1327 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1328 if ((++scmd->retries) <= scmd->allowed
1329 && !blk_noretry_request(scmd->request)) {
1333 * no more retries - report this one back to upper level.
1340 * scsi_eh_lock_door - Prevent medium removal for the specified device
1341 * @sdev: SCSI device to prevent medium removal
1344 * We must be called from process context; scsi_allocate_request()
1348 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1349 * head of the devices request queue, and continue.
1352 * scsi_allocate_request() may sleep waiting for existing requests to
1353 * be processed. However, since we haven't kicked off any request
1354 * processing for this host, this may deadlock.
1356 * If scsi_allocate_request() fails for what ever reason, we
1357 * completely forget to lock the door.
1359 static void scsi_eh_lock_door(struct scsi_device *sdev)
1361 unsigned char cmnd[MAX_COMMAND_SIZE];
1363 cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1367 cmnd[4] = SCSI_REMOVAL_PREVENT;
1370 scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1371 5, NULL, NULL, GFP_KERNEL);
1376 * scsi_restart_operations - restart io operations to the specified host.
1377 * @shost: Host we are restarting.
1380 * When we entered the error handler, we blocked all further i/o to
1381 * this device. we need to 'reverse' this process.
1383 static void scsi_restart_operations(struct Scsi_Host *shost)
1385 struct scsi_device *sdev;
1386 unsigned long flags;
1389 * If the door was locked, we need to insert a door lock request
1390 * onto the head of the SCSI request queue for the device. There
1391 * is no point trying to lock the door of an off-line device.
1393 shost_for_each_device(sdev, shost) {
1394 if (scsi_device_online(sdev) && sdev->locked)
1395 scsi_eh_lock_door(sdev);
1399 * next free up anything directly waiting upon the host. this
1400 * will be requests for character device operations, and also for
1401 * ioctls to queued block devices.
1403 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1406 spin_lock_irqsave(shost->host_lock, flags);
1407 if (scsi_host_set_state(shost, SHOST_RUNNING))
1408 if (scsi_host_set_state(shost, SHOST_CANCEL))
1409 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1410 spin_unlock_irqrestore(shost->host_lock, flags);
1412 wake_up(&shost->host_wait);
1415 * finally we need to re-initiate requests that may be pending. we will
1416 * have had everything blocked while error handling is taking place, and
1417 * now that error recovery is done, we will need to ensure that these
1418 * requests are started.
1420 scsi_run_host_queues(shost);
1424 * scsi_eh_ready_devs - check device ready state and recover if not.
1425 * @shost: host to be recovered.
1426 * @eh_done_q: list_head for processed commands.
1429 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1430 struct list_head *work_q,
1431 struct list_head *done_q)
1433 if (!scsi_eh_stu(shost, work_q, done_q))
1434 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1435 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1436 if (!scsi_eh_host_reset(work_q, done_q))
1437 scsi_eh_offline_sdevs(work_q, done_q);
1441 * scsi_eh_flush_done_q - finish processed commands or retry them.
1442 * @done_q: list_head of processed commands.
1445 void scsi_eh_flush_done_q(struct list_head *done_q)
1447 struct scsi_cmnd *scmd, *next;
1449 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1450 list_del_init(&scmd->eh_entry);
1451 if (scsi_device_online(scmd->device) &&
1452 !blk_noretry_request(scmd->request) &&
1453 (++scmd->retries <= scmd->allowed)) {
1454 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1458 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1461 * If just we got sense for the device (called
1462 * scsi_eh_get_sense), scmd->result is already
1463 * set, do not set DRIVER_TIMEOUT.
1466 scmd->result |= (DRIVER_TIMEOUT << 24);
1467 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1469 current->comm, scmd));
1470 scsi_finish_command(scmd);
1474 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1477 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1478 * @shost: Host to unjam.
1481 * When we come in here, we *know* that all commands on the bus have
1482 * either completed, failed or timed out. we also know that no further
1483 * commands are being sent to the host, so things are relatively quiet
1484 * and we have freedom to fiddle with things as we wish.
1486 * This is only the *default* implementation. it is possible for
1487 * individual drivers to supply their own version of this function, and
1488 * if the maintainer wishes to do this, it is strongly suggested that
1489 * this function be taken as a template and modified. this function
1490 * was designed to correctly handle problems for about 95% of the
1491 * different cases out there, and it should always provide at least a
1492 * reasonable amount of error recovery.
1494 * Any command marked 'failed' or 'timeout' must eventually have
1495 * scsi_finish_cmd() called for it. we do all of the retry stuff
1496 * here, so when we restart the host after we return it should have an
1499 static void scsi_unjam_host(struct Scsi_Host *shost)
1501 unsigned long flags;
1502 LIST_HEAD(eh_work_q);
1503 LIST_HEAD(eh_done_q);
1505 spin_lock_irqsave(shost->host_lock, flags);
1506 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1507 spin_unlock_irqrestore(shost->host_lock, flags);
1509 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1511 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1512 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1513 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1515 scsi_eh_flush_done_q(&eh_done_q);
1519 * scsi_error_handler - SCSI error handler thread
1520 * @data: Host for which we are running.
1523 * This is the main error handling loop. This is run as a kernel thread
1524 * for every SCSI host and handles all error handling activity.
1526 int scsi_error_handler(void *data)
1528 struct Scsi_Host *shost = data;
1530 current->flags |= PF_NOFREEZE;
1533 * We use TASK_INTERRUPTIBLE so that the thread is not
1534 * counted against the load average as a running process.
1535 * We never actually get interrupted because kthread_run
1536 * disables singal delivery for the created thread.
1538 set_current_state(TASK_INTERRUPTIBLE);
1539 while (!kthread_should_stop()) {
1540 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1541 shost->host_failed != shost->host_busy) {
1542 SCSI_LOG_ERROR_RECOVERY(1,
1543 printk("Error handler scsi_eh_%d sleeping\n",
1546 set_current_state(TASK_INTERRUPTIBLE);
1550 __set_current_state(TASK_RUNNING);
1551 SCSI_LOG_ERROR_RECOVERY(1,
1552 printk("Error handler scsi_eh_%d waking up\n",
1556 * We have a host that is failing for some reason. Figure out
1557 * what we need to do to get it up and online again (if we can).
1558 * If we fail, we end up taking the thing offline.
1560 if (shost->transportt->eh_strategy_handler)
1561 shost->transportt->eh_strategy_handler(shost);
1563 scsi_unjam_host(shost);
1566 * Note - if the above fails completely, the action is to take
1567 * individual devices offline and flush the queue of any
1568 * outstanding requests that may have been pending. When we
1569 * restart, we restart any I/O to any other devices on the bus
1570 * which are still online.
1572 scsi_restart_operations(shost);
1573 set_current_state(TASK_INTERRUPTIBLE);
1575 __set_current_state(TASK_RUNNING);
1577 SCSI_LOG_ERROR_RECOVERY(1,
1578 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1579 shost->ehandler = NULL;
1584 * Function: scsi_report_bus_reset()
1586 * Purpose: Utility function used by low-level drivers to report that
1587 * they have observed a bus reset on the bus being handled.
1589 * Arguments: shost - Host in question
1590 * channel - channel on which reset was observed.
1594 * Lock status: Host lock must be held.
1596 * Notes: This only needs to be called if the reset is one which
1597 * originates from an unknown location. Resets originated
1598 * by the mid-level itself don't need to call this, but there
1599 * should be no harm.
1601 * The main purpose of this is to make sure that a CHECK_CONDITION
1602 * is properly treated.
1604 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1606 struct scsi_device *sdev;
1608 __shost_for_each_device(sdev, shost) {
1609 if (channel == sdev_channel(sdev)) {
1610 sdev->was_reset = 1;
1611 sdev->expecting_cc_ua = 1;
1615 EXPORT_SYMBOL(scsi_report_bus_reset);
1618 * Function: scsi_report_device_reset()
1620 * Purpose: Utility function used by low-level drivers to report that
1621 * they have observed a device reset on the device being handled.
1623 * Arguments: shost - Host in question
1624 * channel - channel on which reset was observed
1625 * target - target on which reset was observed
1629 * Lock status: Host lock must be held
1631 * Notes: This only needs to be called if the reset is one which
1632 * originates from an unknown location. Resets originated
1633 * by the mid-level itself don't need to call this, but there
1634 * should be no harm.
1636 * The main purpose of this is to make sure that a CHECK_CONDITION
1637 * is properly treated.
1639 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1641 struct scsi_device *sdev;
1643 __shost_for_each_device(sdev, shost) {
1644 if (channel == sdev_channel(sdev) &&
1645 target == sdev_id(sdev)) {
1646 sdev->was_reset = 1;
1647 sdev->expecting_cc_ua = 1;
1651 EXPORT_SYMBOL(scsi_report_device_reset);
1654 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1659 * Function: scsi_reset_provider
1661 * Purpose: Send requested reset to a bus or device at any phase.
1663 * Arguments: device - device to send reset to
1664 * flag - reset type (see scsi.h)
1666 * Returns: SUCCESS/FAILURE.
1668 * Notes: This is used by the SCSI Generic driver to provide
1669 * Bus/Device reset capability.
1672 scsi_reset_provider(struct scsi_device *dev, int flag)
1674 struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1678 scmd->request = &req;
1679 memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1681 memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1683 scmd->scsi_done = scsi_reset_provider_done_command;
1685 scmd->buffer = NULL;
1687 scmd->request_buffer = NULL;
1688 scmd->request_bufflen = 0;
1692 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
1694 init_timer(&scmd->eh_timeout);
1697 * Sometimes the command can get back into the timer chain,
1698 * so use the pid as an identifier.
1703 case SCSI_TRY_RESET_DEVICE:
1704 rtn = scsi_try_bus_device_reset(scmd);
1708 case SCSI_TRY_RESET_BUS:
1709 rtn = scsi_try_bus_reset(scmd);
1713 case SCSI_TRY_RESET_HOST:
1714 rtn = scsi_try_host_reset(scmd);
1720 scsi_next_command(scmd);
1723 EXPORT_SYMBOL(scsi_reset_provider);
1726 * scsi_normalize_sense - normalize main elements from either fixed or
1727 * descriptor sense data format into a common format.
1729 * @sense_buffer: byte array containing sense data returned by device
1730 * @sb_len: number of valid bytes in sense_buffer
1731 * @sshdr: pointer to instance of structure that common
1732 * elements are written to.
1735 * The "main elements" from sense data are: response_code, sense_key,
1736 * asc, ascq and additional_length (only for descriptor format).
1738 * Typically this function can be called after a device has
1739 * responded to a SCSI command with the CHECK_CONDITION status.
1742 * 1 if valid sense data information found, else 0;
1744 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1745 struct scsi_sense_hdr *sshdr)
1747 if (!sense_buffer || !sb_len)
1750 memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1752 sshdr->response_code = (sense_buffer[0] & 0x7f);
1754 if (!scsi_sense_valid(sshdr))
1757 if (sshdr->response_code >= 0x72) {
1762 sshdr->sense_key = (sense_buffer[1] & 0xf);
1764 sshdr->asc = sense_buffer[2];
1766 sshdr->ascq = sense_buffer[3];
1768 sshdr->additional_length = sense_buffer[7];
1774 sshdr->sense_key = (sense_buffer[2] & 0xf);
1776 sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1777 sb_len : (sense_buffer[7] + 8);
1779 sshdr->asc = sense_buffer[12];
1781 sshdr->ascq = sense_buffer[13];
1787 EXPORT_SYMBOL(scsi_normalize_sense);
1789 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1790 struct scsi_sense_hdr *sshdr)
1792 return scsi_normalize_sense(cmd->sense_buffer,
1793 sizeof(cmd->sense_buffer), sshdr);
1795 EXPORT_SYMBOL(scsi_command_normalize_sense);
1798 * scsi_sense_desc_find - search for a given descriptor type in
1799 * descriptor sense data format.
1801 * @sense_buffer: byte array of descriptor format sense data
1802 * @sb_len: number of valid bytes in sense_buffer
1803 * @desc_type: value of descriptor type to find
1804 * (e.g. 0 -> information)
1807 * only valid when sense data is in descriptor format
1810 * pointer to start of (first) descriptor if found else NULL
1812 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1815 int add_sen_len, add_len, desc_len, k;
1818 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1820 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1822 add_sen_len = (add_sen_len < (sb_len - 8)) ?
1823 add_sen_len : (sb_len - 8);
1824 descp = &sense_buffer[8];
1825 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1827 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1828 desc_len = add_len + 2;
1829 if (descp[0] == desc_type)
1831 if (add_len < 0) // short descriptor ??
1836 EXPORT_SYMBOL(scsi_sense_desc_find);
1839 * scsi_get_sense_info_fld - attempts to get information field from
1840 * sense data (either fixed or descriptor format)
1842 * @sense_buffer: byte array of sense data
1843 * @sb_len: number of valid bytes in sense_buffer
1844 * @info_out: pointer to 64 integer where 8 or 4 byte information
1845 * field will be placed if found.
1848 * 1 if information field found, 0 if not found.
1850 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1859 switch (sense_buffer[0] & 0x7f) {
1862 if (sense_buffer[0] & 0x80) {
1863 *info_out = (sense_buffer[3] << 24) +
1864 (sense_buffer[4] << 16) +
1865 (sense_buffer[5] << 8) + sense_buffer[6];
1871 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1873 if (ucp && (0xa == ucp[1])) {
1875 for (j = 0; j < 8; ++j) {
1888 EXPORT_SYMBOL(scsi_get_sense_info_fld);