2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
10 #include <linux/bio.h>
11 #include <linux/bitops.h>
12 #include <linux/blkdev.h>
13 #include <linux/completion.h>
14 #include <linux/kernel.h>
15 #include <linux/export.h>
16 #include <linux/mempool.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/delay.h>
21 #include <linux/hardirq.h>
22 #include <linux/scatterlist.h>
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_cmnd.h>
26 #include <scsi/scsi_dbg.h>
27 #include <scsi/scsi_device.h>
28 #include <scsi/scsi_driver.h>
29 #include <scsi/scsi_eh.h>
30 #include <scsi/scsi_host.h>
32 #include "scsi_priv.h"
33 #include "scsi_logging.h"
36 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
37 #define SG_MEMPOOL_SIZE 2
39 struct scsi_host_sg_pool
{
42 struct kmem_cache
*slab
;
46 #define SP(x) { x, "sgpool-" __stringify(x) }
47 #if (SCSI_MAX_SG_SEGMENTS < 32)
48 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
50 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
53 #if (SCSI_MAX_SG_SEGMENTS > 32)
55 #if (SCSI_MAX_SG_SEGMENTS > 64)
57 #if (SCSI_MAX_SG_SEGMENTS > 128)
59 #if (SCSI_MAX_SG_SEGMENTS > 256)
60 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
65 SP(SCSI_MAX_SG_SEGMENTS
)
69 struct kmem_cache
*scsi_sdb_cache
;
72 #include <acpi/acpi_bus.h>
74 static bool acpi_scsi_bus_match(struct device
*dev
)
76 return dev
->bus
== &scsi_bus_type
;
79 int scsi_register_acpi_bus_type(struct acpi_bus_type
*bus
)
81 bus
->match
= acpi_scsi_bus_match
;
82 return register_acpi_bus_type(bus
);
84 EXPORT_SYMBOL_GPL(scsi_register_acpi_bus_type
);
86 void scsi_unregister_acpi_bus_type(struct acpi_bus_type
*bus
)
88 unregister_acpi_bus_type(bus
);
90 EXPORT_SYMBOL_GPL(scsi_unregister_acpi_bus_type
);
94 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
95 * not change behaviour from the previous unplug mechanism, experimentation
96 * may prove this needs changing.
98 #define SCSI_QUEUE_DELAY 3
101 * Function: scsi_unprep_request()
103 * Purpose: Remove all preparation done for a request, including its
104 * associated scsi_cmnd, so that it can be requeued.
106 * Arguments: req - request to unprepare
108 * Lock status: Assumed that no locks are held upon entry.
112 static void scsi_unprep_request(struct request
*req
)
114 struct scsi_cmnd
*cmd
= req
->special
;
116 blk_unprep_request(req
);
119 scsi_put_command(cmd
);
123 * __scsi_queue_insert - private queue insertion
124 * @cmd: The SCSI command being requeued
125 * @reason: The reason for the requeue
126 * @unbusy: Whether the queue should be unbusied
128 * This is a private queue insertion. The public interface
129 * scsi_queue_insert() always assumes the queue should be unbusied
130 * because it's always called before the completion. This function is
131 * for a requeue after completion, which should only occur in this
134 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
136 struct Scsi_Host
*host
= cmd
->device
->host
;
137 struct scsi_device
*device
= cmd
->device
;
138 struct scsi_target
*starget
= scsi_target(device
);
139 struct request_queue
*q
= device
->request_queue
;
143 printk("Inserting command %p into mlqueue\n", cmd
));
146 * Set the appropriate busy bit for the device/host.
148 * If the host/device isn't busy, assume that something actually
149 * completed, and that we should be able to queue a command now.
151 * Note that the prior mid-layer assumption that any host could
152 * always queue at least one command is now broken. The mid-layer
153 * will implement a user specifiable stall (see
154 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
155 * if a command is requeued with no other commands outstanding
156 * either for the device or for the host.
159 case SCSI_MLQUEUE_HOST_BUSY
:
160 host
->host_blocked
= host
->max_host_blocked
;
162 case SCSI_MLQUEUE_DEVICE_BUSY
:
163 case SCSI_MLQUEUE_EH_RETRY
:
164 device
->device_blocked
= device
->max_device_blocked
;
166 case SCSI_MLQUEUE_TARGET_BUSY
:
167 starget
->target_blocked
= starget
->max_target_blocked
;
172 * Decrement the counters, since these commands are no longer
173 * active on the host/device.
176 scsi_device_unbusy(device
);
179 * Requeue this command. It will go before all other commands
180 * that are already in the queue. Schedule requeue work under
181 * lock such that the kblockd_schedule_work() call happens
182 * before blk_cleanup_queue() finishes.
184 spin_lock_irqsave(q
->queue_lock
, flags
);
185 blk_requeue_request(q
, cmd
->request
);
186 kblockd_schedule_work(q
, &device
->requeue_work
);
187 spin_unlock_irqrestore(q
->queue_lock
, flags
);
191 * Function: scsi_queue_insert()
193 * Purpose: Insert a command in the midlevel queue.
195 * Arguments: cmd - command that we are adding to queue.
196 * reason - why we are inserting command to queue.
198 * Lock status: Assumed that lock is not held upon entry.
202 * Notes: We do this for one of two cases. Either the host is busy
203 * and it cannot accept any more commands for the time being,
204 * or the device returned QUEUE_FULL and can accept no more
206 * Notes: This could be called either from an interrupt context or a
207 * normal process context.
209 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
211 __scsi_queue_insert(cmd
, reason
, 1);
214 * scsi_execute - insert request and wait for the result
217 * @data_direction: data direction
218 * @buffer: data buffer
219 * @bufflen: len of buffer
220 * @sense: optional sense buffer
221 * @timeout: request timeout in seconds
222 * @retries: number of times to retry request
223 * @flags: or into request flags;
224 * @resid: optional residual length
226 * returns the req->errors value which is the scsi_cmnd result
229 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
230 int data_direction
, void *buffer
, unsigned bufflen
,
231 unsigned char *sense
, int timeout
, int retries
, int flags
,
235 int write
= (data_direction
== DMA_TO_DEVICE
);
236 int ret
= DRIVER_ERROR
<< 24;
238 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
242 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
243 buffer
, bufflen
, __GFP_WAIT
))
246 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
247 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
250 req
->retries
= retries
;
251 req
->timeout
= timeout
;
252 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
253 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
256 * head injection *required* here otherwise quiesce won't work
258 blk_execute_rq(req
->q
, NULL
, req
, 1);
261 * Some devices (USB mass-storage in particular) may transfer
262 * garbage data together with a residue indicating that the data
263 * is invalid. Prevent the garbage from being misinterpreted
264 * and prevent security leaks by zeroing out the excess data.
266 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
267 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
270 *resid
= req
->resid_len
;
273 blk_put_request(req
);
277 EXPORT_SYMBOL(scsi_execute
);
279 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
280 int data_direction
, void *buffer
, unsigned bufflen
,
281 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
282 int *resid
, int flags
)
288 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
290 return DRIVER_ERROR
<< 24;
292 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
293 sense
, timeout
, retries
, flags
, resid
);
295 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
300 EXPORT_SYMBOL(scsi_execute_req_flags
);
303 * Function: scsi_init_cmd_errh()
305 * Purpose: Initialize cmd fields related to error handling.
307 * Arguments: cmd - command that is ready to be queued.
309 * Notes: This function has the job of initializing a number of
310 * fields related to error handling. Typically this will
311 * be called once for each command, as required.
313 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
315 cmd
->serial_number
= 0;
316 scsi_set_resid(cmd
, 0);
317 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
318 if (cmd
->cmd_len
== 0)
319 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
322 void scsi_device_unbusy(struct scsi_device
*sdev
)
324 struct Scsi_Host
*shost
= sdev
->host
;
325 struct scsi_target
*starget
= scsi_target(sdev
);
328 spin_lock_irqsave(shost
->host_lock
, flags
);
330 starget
->target_busy
--;
331 if (unlikely(scsi_host_in_recovery(shost
) &&
332 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
333 scsi_eh_wakeup(shost
);
334 spin_unlock(shost
->host_lock
);
335 spin_lock(sdev
->request_queue
->queue_lock
);
337 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
341 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
342 * and call blk_run_queue for all the scsi_devices on the target -
343 * including current_sdev first.
345 * Called with *no* scsi locks held.
347 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
349 struct Scsi_Host
*shost
= current_sdev
->host
;
350 struct scsi_device
*sdev
, *tmp
;
351 struct scsi_target
*starget
= scsi_target(current_sdev
);
354 spin_lock_irqsave(shost
->host_lock
, flags
);
355 starget
->starget_sdev_user
= NULL
;
356 spin_unlock_irqrestore(shost
->host_lock
, flags
);
359 * Call blk_run_queue for all LUNs on the target, starting with
360 * current_sdev. We race with others (to set starget_sdev_user),
361 * but in most cases, we will be first. Ideally, each LU on the
362 * target would get some limited time or requests on the target.
364 blk_run_queue(current_sdev
->request_queue
);
366 spin_lock_irqsave(shost
->host_lock
, flags
);
367 if (starget
->starget_sdev_user
)
369 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
370 same_target_siblings
) {
371 if (sdev
== current_sdev
)
373 if (scsi_device_get(sdev
))
376 spin_unlock_irqrestore(shost
->host_lock
, flags
);
377 blk_run_queue(sdev
->request_queue
);
378 spin_lock_irqsave(shost
->host_lock
, flags
);
380 scsi_device_put(sdev
);
383 spin_unlock_irqrestore(shost
->host_lock
, flags
);
386 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
388 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
394 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
396 return ((starget
->can_queue
> 0 &&
397 starget
->target_busy
>= starget
->can_queue
) ||
398 starget
->target_blocked
);
401 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
403 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
404 shost
->host_blocked
|| shost
->host_self_blocked
)
411 * Function: scsi_run_queue()
413 * Purpose: Select a proper request queue to serve next
415 * Arguments: q - last request's queue
419 * Notes: The previous command was completely finished, start
420 * a new one if possible.
422 static void scsi_run_queue(struct request_queue
*q
)
424 struct scsi_device
*sdev
= q
->queuedata
;
425 struct Scsi_Host
*shost
;
426 LIST_HEAD(starved_list
);
430 if (scsi_target(sdev
)->single_lun
)
431 scsi_single_lun_run(sdev
);
433 spin_lock_irqsave(shost
->host_lock
, flags
);
434 list_splice_init(&shost
->starved_list
, &starved_list
);
436 while (!list_empty(&starved_list
)) {
437 struct request_queue
*slq
;
440 * As long as shost is accepting commands and we have
441 * starved queues, call blk_run_queue. scsi_request_fn
442 * drops the queue_lock and can add us back to the
445 * host_lock protects the starved_list and starved_entry.
446 * scsi_request_fn must get the host_lock before checking
447 * or modifying starved_list or starved_entry.
449 if (scsi_host_is_busy(shost
))
452 sdev
= list_entry(starved_list
.next
,
453 struct scsi_device
, starved_entry
);
454 list_del_init(&sdev
->starved_entry
);
455 if (scsi_target_is_busy(scsi_target(sdev
))) {
456 list_move_tail(&sdev
->starved_entry
,
457 &shost
->starved_list
);
462 * Once we drop the host lock, a racing scsi_remove_device()
463 * call may remove the sdev from the starved list and destroy
464 * it and the queue. Mitigate by taking a reference to the
465 * queue and never touching the sdev again after we drop the
466 * host lock. Note: if __scsi_remove_device() invokes
467 * blk_cleanup_queue() before the queue is run from this
468 * function then blk_run_queue() will return immediately since
469 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
471 slq
= sdev
->request_queue
;
472 if (!blk_get_queue(slq
))
474 spin_unlock_irqrestore(shost
->host_lock
, flags
);
479 spin_lock_irqsave(shost
->host_lock
, flags
);
481 /* put any unprocessed entries back */
482 list_splice(&starved_list
, &shost
->starved_list
);
483 spin_unlock_irqrestore(shost
->host_lock
, flags
);
488 void scsi_requeue_run_queue(struct work_struct
*work
)
490 struct scsi_device
*sdev
;
491 struct request_queue
*q
;
493 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
494 q
= sdev
->request_queue
;
499 * Function: scsi_requeue_command()
501 * Purpose: Handle post-processing of completed commands.
503 * Arguments: q - queue to operate on
504 * cmd - command that may need to be requeued.
508 * Notes: After command completion, there may be blocks left
509 * over which weren't finished by the previous command
510 * this can be for a number of reasons - the main one is
511 * I/O errors in the middle of the request, in which case
512 * we need to request the blocks that come after the bad
514 * Notes: Upon return, cmd is a stale pointer.
516 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
518 struct scsi_device
*sdev
= cmd
->device
;
519 struct request
*req
= cmd
->request
;
523 * We need to hold a reference on the device to avoid the queue being
524 * killed after the unlock and before scsi_run_queue is invoked which
525 * may happen because scsi_unprep_request() puts the command which
526 * releases its reference on the device.
528 get_device(&sdev
->sdev_gendev
);
530 spin_lock_irqsave(q
->queue_lock
, flags
);
531 scsi_unprep_request(req
);
532 blk_requeue_request(q
, req
);
533 spin_unlock_irqrestore(q
->queue_lock
, flags
);
537 put_device(&sdev
->sdev_gendev
);
540 void scsi_next_command(struct scsi_cmnd
*cmd
)
542 struct scsi_device
*sdev
= cmd
->device
;
543 struct request_queue
*q
= sdev
->request_queue
;
545 /* need to hold a reference on the device before we let go of the cmd */
546 get_device(&sdev
->sdev_gendev
);
548 scsi_put_command(cmd
);
551 /* ok to remove device now */
552 put_device(&sdev
->sdev_gendev
);
555 void scsi_run_host_queues(struct Scsi_Host
*shost
)
557 struct scsi_device
*sdev
;
559 shost_for_each_device(sdev
, shost
)
560 scsi_run_queue(sdev
->request_queue
);
563 static void __scsi_release_buffers(struct scsi_cmnd
*, int);
566 * Function: scsi_end_request()
568 * Purpose: Post-processing of completed commands (usually invoked at end
569 * of upper level post-processing and scsi_io_completion).
571 * Arguments: cmd - command that is complete.
572 * error - 0 if I/O indicates success, < 0 for I/O error.
573 * bytes - number of bytes of completed I/O
574 * requeue - indicates whether we should requeue leftovers.
576 * Lock status: Assumed that lock is not held upon entry.
578 * Returns: cmd if requeue required, NULL otherwise.
580 * Notes: This is called for block device requests in order to
581 * mark some number of sectors as complete.
583 * We are guaranteeing that the request queue will be goosed
584 * at some point during this call.
585 * Notes: If cmd was requeued, upon return it will be a stale pointer.
587 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int error
,
588 int bytes
, int requeue
)
590 struct request_queue
*q
= cmd
->device
->request_queue
;
591 struct request
*req
= cmd
->request
;
594 * If there are blocks left over at the end, set up the command
595 * to queue the remainder of them.
597 if (blk_end_request(req
, error
, bytes
)) {
598 /* kill remainder if no retrys */
599 if (error
&& scsi_noretry_cmd(cmd
))
600 blk_end_request_all(req
, error
);
604 * Bleah. Leftovers again. Stick the
605 * leftovers in the front of the
606 * queue, and goose the queue again.
608 scsi_release_buffers(cmd
);
609 scsi_requeue_command(q
, cmd
);
617 * This will goose the queue request function at the end, so we don't
618 * need to worry about launching another command.
620 __scsi_release_buffers(cmd
, 0);
621 scsi_next_command(cmd
);
625 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
629 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
634 index
= get_count_order(nents
) - 3;
639 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
641 struct scsi_host_sg_pool
*sgp
;
643 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
644 mempool_free(sgl
, sgp
->pool
);
647 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
649 struct scsi_host_sg_pool
*sgp
;
651 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
652 return mempool_alloc(sgp
->pool
, gfp_mask
);
655 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
662 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
663 gfp_mask
, scsi_sg_alloc
);
665 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
671 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
673 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
676 static void __scsi_release_buffers(struct scsi_cmnd
*cmd
, int do_bidi_check
)
679 if (cmd
->sdb
.table
.nents
)
680 scsi_free_sgtable(&cmd
->sdb
);
682 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
684 if (do_bidi_check
&& scsi_bidi_cmnd(cmd
)) {
685 struct scsi_data_buffer
*bidi_sdb
=
686 cmd
->request
->next_rq
->special
;
687 scsi_free_sgtable(bidi_sdb
);
688 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
689 cmd
->request
->next_rq
->special
= NULL
;
692 if (scsi_prot_sg_count(cmd
))
693 scsi_free_sgtable(cmd
->prot_sdb
);
697 * Function: scsi_release_buffers()
699 * Purpose: Completion processing for block device I/O requests.
701 * Arguments: cmd - command that we are bailing.
703 * Lock status: Assumed that no lock is held upon entry.
707 * Notes: In the event that an upper level driver rejects a
708 * command, we must release resources allocated during
709 * the __init_io() function. Primarily this would involve
710 * the scatter-gather table, and potentially any bounce
713 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
715 __scsi_release_buffers(cmd
, 1);
717 EXPORT_SYMBOL(scsi_release_buffers
);
720 * __scsi_error_from_host_byte - translate SCSI error code into errno
721 * @cmd: SCSI command (unused)
722 * @result: scsi error code
724 * Translate SCSI error code into standard UNIX errno.
726 * -ENOLINK temporary transport failure
727 * -EREMOTEIO permanent target failure, do not retry
728 * -EBADE permanent nexus failure, retry on other path
729 * -ENOSPC No write space available
730 * -ENODATA Medium error
731 * -EIO unspecified I/O error
733 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
737 switch(host_byte(result
)) {
738 case DID_TRANSPORT_FAILFAST
:
741 case DID_TARGET_FAILURE
:
742 set_host_byte(cmd
, DID_OK
);
745 case DID_NEXUS_FAILURE
:
746 set_host_byte(cmd
, DID_OK
);
749 case DID_ALLOC_FAILURE
:
750 set_host_byte(cmd
, DID_OK
);
753 case DID_MEDIUM_ERROR
:
754 set_host_byte(cmd
, DID_OK
);
766 * Function: scsi_io_completion()
768 * Purpose: Completion processing for block device I/O requests.
770 * Arguments: cmd - command that is finished.
772 * Lock status: Assumed that no lock is held upon entry.
776 * Notes: This function is matched in terms of capabilities to
777 * the function that created the scatter-gather list.
778 * In other words, if there are no bounce buffers
779 * (the normal case for most drivers), we don't need
780 * the logic to deal with cleaning up afterwards.
782 * We must call scsi_end_request(). This will finish off
783 * the specified number of sectors. If we are done, the
784 * command block will be released and the queue function
785 * will be goosed. If we are not done then we have to
786 * figure out what to do next:
788 * a) We can call scsi_requeue_command(). The request
789 * will be unprepared and put back on the queue. Then
790 * a new command will be created for it. This should
791 * be used if we made forward progress, or if we want
792 * to switch from READ(10) to READ(6) for example.
794 * b) We can call scsi_queue_insert(). The request will
795 * be put back on the queue and retried using the same
796 * command as before, possibly after a delay.
798 * c) We can call blk_end_request() with -EIO to fail
799 * the remainder of the request.
801 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
803 int result
= cmd
->result
;
804 struct request_queue
*q
= cmd
->device
->request_queue
;
805 struct request
*req
= cmd
->request
;
807 struct scsi_sense_hdr sshdr
;
809 int sense_deferred
= 0;
810 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
811 ACTION_DELAYED_RETRY
} action
;
812 char *description
= NULL
;
815 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
817 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
820 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
822 if (sense_valid
&& req
->sense
) {
824 * SG_IO wants current and deferred errors
826 int len
= 8 + cmd
->sense_buffer
[7];
828 if (len
> SCSI_SENSE_BUFFERSIZE
)
829 len
= SCSI_SENSE_BUFFERSIZE
;
830 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
831 req
->sense_len
= len
;
834 error
= __scsi_error_from_host_byte(cmd
, result
);
837 * __scsi_error_from_host_byte may have reset the host_byte
839 req
->errors
= cmd
->result
;
841 req
->resid_len
= scsi_get_resid(cmd
);
843 if (scsi_bidi_cmnd(cmd
)) {
845 * Bidi commands Must be complete as a whole,
846 * both sides at once.
848 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
850 scsi_release_buffers(cmd
);
851 blk_end_request_all(req
, 0);
853 scsi_next_command(cmd
);
858 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
859 BUG_ON(blk_bidi_rq(req
));
862 * Next deal with any sectors which we were able to correctly
865 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
867 blk_rq_sectors(req
), good_bytes
));
870 * Recovered errors need reporting, but they're always treated
871 * as success, so fiddle the result code here. For BLOCK_PC
872 * we already took a copy of the original into rq->errors which
873 * is what gets returned to the user
875 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
876 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
877 * print since caller wants ATA registers. Only occurs on
878 * SCSI ATA PASS_THROUGH commands when CK_COND=1
880 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
882 else if (!(req
->cmd_flags
& REQ_QUIET
))
883 scsi_print_sense("", cmd
);
885 /* BLOCK_PC may have set error */
890 * A number of bytes were successfully read. If there
891 * are leftovers and there is some kind of error
892 * (result != 0), retry the rest.
894 if (scsi_end_request(cmd
, error
, good_bytes
, result
== 0) == NULL
)
897 error
= __scsi_error_from_host_byte(cmd
, result
);
899 if (host_byte(result
) == DID_RESET
) {
900 /* Third party bus reset or reset for error recovery
901 * reasons. Just retry the command and see what
904 action
= ACTION_RETRY
;
905 } else if (sense_valid
&& !sense_deferred
) {
906 switch (sshdr
.sense_key
) {
908 if (cmd
->device
->removable
) {
909 /* Detected disc change. Set a bit
910 * and quietly refuse further access.
912 cmd
->device
->changed
= 1;
913 description
= "Media Changed";
914 action
= ACTION_FAIL
;
916 /* Must have been a power glitch, or a
917 * bus reset. Could not have been a
918 * media change, so we just retry the
919 * command and see what happens.
921 action
= ACTION_RETRY
;
924 case ILLEGAL_REQUEST
:
925 /* If we had an ILLEGAL REQUEST returned, then
926 * we may have performed an unsupported
927 * command. The only thing this should be
928 * would be a ten byte read where only a six
929 * byte read was supported. Also, on a system
930 * where READ CAPACITY failed, we may have
931 * read past the end of the disk.
933 if ((cmd
->device
->use_10_for_rw
&&
934 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
935 (cmd
->cmnd
[0] == READ_10
||
936 cmd
->cmnd
[0] == WRITE_10
)) {
937 /* This will issue a new 6-byte command. */
938 cmd
->device
->use_10_for_rw
= 0;
939 action
= ACTION_REPREP
;
940 } else if (sshdr
.asc
== 0x10) /* DIX */ {
941 description
= "Host Data Integrity Failure";
942 action
= ACTION_FAIL
;
944 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
945 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
946 switch (cmd
->cmnd
[0]) {
948 description
= "Discard failure";
952 if (cmd
->cmnd
[1] & 0x8)
953 description
= "Discard failure";
956 "Write same failure";
959 description
= "Invalid command failure";
962 action
= ACTION_FAIL
;
965 action
= ACTION_FAIL
;
967 case ABORTED_COMMAND
:
968 action
= ACTION_FAIL
;
969 if (sshdr
.asc
== 0x10) { /* DIF */
970 description
= "Target Data Integrity Failure";
975 /* If the device is in the process of becoming
976 * ready, or has a temporary blockage, retry.
978 if (sshdr
.asc
== 0x04) {
979 switch (sshdr
.ascq
) {
980 case 0x01: /* becoming ready */
981 case 0x04: /* format in progress */
982 case 0x05: /* rebuild in progress */
983 case 0x06: /* recalculation in progress */
984 case 0x07: /* operation in progress */
985 case 0x08: /* Long write in progress */
986 case 0x09: /* self test in progress */
987 case 0x14: /* space allocation in progress */
988 action
= ACTION_DELAYED_RETRY
;
991 description
= "Device not ready";
992 action
= ACTION_FAIL
;
996 description
= "Device not ready";
997 action
= ACTION_FAIL
;
1000 case VOLUME_OVERFLOW
:
1001 /* See SSC3rXX or current. */
1002 action
= ACTION_FAIL
;
1005 description
= "Unhandled sense code";
1006 action
= ACTION_FAIL
;
1010 description
= "Unhandled error code";
1011 action
= ACTION_FAIL
;
1016 /* Give up and fail the remainder of the request */
1017 scsi_release_buffers(cmd
);
1018 if (!(req
->cmd_flags
& REQ_QUIET
)) {
1020 scmd_printk(KERN_INFO
, cmd
, "%s\n",
1022 scsi_print_result(cmd
);
1023 if (driver_byte(result
) & DRIVER_SENSE
)
1024 scsi_print_sense("", cmd
);
1025 scsi_print_command(cmd
);
1027 if (blk_end_request_err(req
, error
))
1028 scsi_requeue_command(q
, cmd
);
1030 scsi_next_command(cmd
);
1033 /* Unprep the request and put it back at the head of the queue.
1034 * A new command will be prepared and issued.
1036 scsi_release_buffers(cmd
);
1037 scsi_requeue_command(q
, cmd
);
1040 /* Retry the same command immediately */
1041 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1043 case ACTION_DELAYED_RETRY
:
1044 /* Retry the same command after a delay */
1045 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1050 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
1056 * If sg table allocation fails, requeue request later.
1058 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
1060 return BLKPREP_DEFER
;
1066 * Next, walk the list, and fill in the addresses and sizes of
1069 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1070 BUG_ON(count
> sdb
->table
.nents
);
1071 sdb
->table
.nents
= count
;
1072 sdb
->length
= blk_rq_bytes(req
);
1077 * Function: scsi_init_io()
1079 * Purpose: SCSI I/O initialize function.
1081 * Arguments: cmd - Command descriptor we wish to initialize
1083 * Returns: 0 on success
1084 * BLKPREP_DEFER if the failure is retryable
1085 * BLKPREP_KILL if the failure is fatal
1087 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
1089 struct request
*rq
= cmd
->request
;
1091 int error
= scsi_init_sgtable(rq
, &cmd
->sdb
, gfp_mask
);
1095 if (blk_bidi_rq(rq
)) {
1096 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
1097 scsi_sdb_cache
, GFP_ATOMIC
);
1099 error
= BLKPREP_DEFER
;
1103 rq
->next_rq
->special
= bidi_sdb
;
1104 error
= scsi_init_sgtable(rq
->next_rq
, bidi_sdb
, GFP_ATOMIC
);
1109 if (blk_integrity_rq(rq
)) {
1110 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1113 BUG_ON(prot_sdb
== NULL
);
1114 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1116 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1117 error
= BLKPREP_DEFER
;
1121 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1122 prot_sdb
->table
.sgl
);
1123 BUG_ON(unlikely(count
> ivecs
));
1124 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1126 cmd
->prot_sdb
= prot_sdb
;
1127 cmd
->prot_sdb
->table
.nents
= count
;
1133 scsi_release_buffers(cmd
);
1134 cmd
->request
->special
= NULL
;
1135 scsi_put_command(cmd
);
1138 EXPORT_SYMBOL(scsi_init_io
);
1140 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1141 struct request
*req
)
1143 struct scsi_cmnd
*cmd
;
1145 if (!req
->special
) {
1146 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1154 /* pull a tag out of the request if we have one */
1155 cmd
->tag
= req
->tag
;
1158 cmd
->cmnd
= req
->cmd
;
1159 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1164 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1166 struct scsi_cmnd
*cmd
;
1167 int ret
= scsi_prep_state_check(sdev
, req
);
1169 if (ret
!= BLKPREP_OK
)
1172 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1174 return BLKPREP_DEFER
;
1177 * BLOCK_PC requests may transfer data, in which case they must
1178 * a bio attached to them. Or they might contain a SCSI command
1179 * that does not transfer data, in which case they may optionally
1180 * submit a request without an attached bio.
1185 BUG_ON(!req
->nr_phys_segments
);
1187 ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1191 BUG_ON(blk_rq_bytes(req
));
1193 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1197 cmd
->cmd_len
= req
->cmd_len
;
1198 if (!blk_rq_bytes(req
))
1199 cmd
->sc_data_direction
= DMA_NONE
;
1200 else if (rq_data_dir(req
) == WRITE
)
1201 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1203 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1205 cmd
->transfersize
= blk_rq_bytes(req
);
1206 cmd
->allowed
= req
->retries
;
1209 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1212 * Setup a REQ_TYPE_FS command. These are simple read/write request
1213 * from filesystems that still need to be translated to SCSI CDBs from
1216 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1218 struct scsi_cmnd
*cmd
;
1219 int ret
= scsi_prep_state_check(sdev
, req
);
1221 if (ret
!= BLKPREP_OK
)
1224 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1225 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1226 ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1227 if (ret
!= BLKPREP_OK
)
1232 * Filesystem requests must transfer data.
1234 BUG_ON(!req
->nr_phys_segments
);
1236 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1238 return BLKPREP_DEFER
;
1240 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1241 return scsi_init_io(cmd
, GFP_ATOMIC
);
1243 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1245 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1247 int ret
= BLKPREP_OK
;
1250 * If the device is not in running state we will reject some
1253 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1254 switch (sdev
->sdev_state
) {
1256 case SDEV_TRANSPORT_OFFLINE
:
1258 * If the device is offline we refuse to process any
1259 * commands. The device must be brought online
1260 * before trying any recovery commands.
1262 sdev_printk(KERN_ERR
, sdev
,
1263 "rejecting I/O to offline device\n");
1268 * If the device is fully deleted, we refuse to
1269 * process any commands as well.
1271 sdev_printk(KERN_ERR
, sdev
,
1272 "rejecting I/O to dead device\n");
1277 case SDEV_CREATED_BLOCK
:
1279 * If the devices is blocked we defer normal commands.
1281 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1282 ret
= BLKPREP_DEFER
;
1286 * For any other not fully online state we only allow
1287 * special commands. In particular any user initiated
1288 * command is not allowed.
1290 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1297 EXPORT_SYMBOL(scsi_prep_state_check
);
1299 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1301 struct scsi_device
*sdev
= q
->queuedata
;
1305 req
->errors
= DID_NO_CONNECT
<< 16;
1306 /* release the command and kill it */
1308 struct scsi_cmnd
*cmd
= req
->special
;
1309 scsi_release_buffers(cmd
);
1310 scsi_put_command(cmd
);
1311 req
->special
= NULL
;
1316 * If we defer, the blk_peek_request() returns NULL, but the
1317 * queue must be restarted, so we schedule a callback to happen
1320 if (sdev
->device_busy
== 0)
1321 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1324 req
->cmd_flags
|= REQ_DONTPREP
;
1329 EXPORT_SYMBOL(scsi_prep_return
);
1331 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1333 struct scsi_device
*sdev
= q
->queuedata
;
1334 int ret
= BLKPREP_KILL
;
1336 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1337 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1338 return scsi_prep_return(q
, req
, ret
);
1340 EXPORT_SYMBOL(scsi_prep_fn
);
1343 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1346 * Called with the queue_lock held.
1348 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1349 struct scsi_device
*sdev
)
1351 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1353 * unblock after device_blocked iterates to zero
1355 if (--sdev
->device_blocked
== 0) {
1357 sdev_printk(KERN_INFO
, sdev
,
1358 "unblocking device at zero depth\n"));
1360 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1364 if (scsi_device_is_busy(sdev
))
1372 * scsi_target_queue_ready: checks if there we can send commands to target
1373 * @sdev: scsi device on starget to check.
1375 * Called with the host lock held.
1377 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1378 struct scsi_device
*sdev
)
1380 struct scsi_target
*starget
= scsi_target(sdev
);
1382 if (starget
->single_lun
) {
1383 if (starget
->starget_sdev_user
&&
1384 starget
->starget_sdev_user
!= sdev
)
1386 starget
->starget_sdev_user
= sdev
;
1389 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1391 * unblock after target_blocked iterates to zero
1393 if (--starget
->target_blocked
== 0) {
1394 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1395 "unblocking target at zero depth\n"));
1400 if (scsi_target_is_busy(starget
)) {
1401 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1409 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1410 * return 0. We must end up running the queue again whenever 0 is
1411 * returned, else IO can hang.
1413 * Called with host_lock held.
1415 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1416 struct Scsi_Host
*shost
,
1417 struct scsi_device
*sdev
)
1419 if (scsi_host_in_recovery(shost
))
1421 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1423 * unblock after host_blocked iterates to zero
1425 if (--shost
->host_blocked
== 0) {
1427 printk("scsi%d unblocking host at zero depth\n",
1433 if (scsi_host_is_busy(shost
)) {
1434 if (list_empty(&sdev
->starved_entry
))
1435 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1439 /* We're OK to process the command, so we can't be starved */
1440 if (!list_empty(&sdev
->starved_entry
))
1441 list_del_init(&sdev
->starved_entry
);
1447 * Busy state exporting function for request stacking drivers.
1449 * For efficiency, no lock is taken to check the busy state of
1450 * shost/starget/sdev, since the returned value is not guaranteed and
1451 * may be changed after request stacking drivers call the function,
1452 * regardless of taking lock or not.
1454 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1455 * needs to return 'not busy'. Otherwise, request stacking drivers
1456 * may hold requests forever.
1458 static int scsi_lld_busy(struct request_queue
*q
)
1460 struct scsi_device
*sdev
= q
->queuedata
;
1461 struct Scsi_Host
*shost
;
1463 if (blk_queue_dying(q
))
1469 * Ignore host/starget busy state.
1470 * Since block layer does not have a concept of fairness across
1471 * multiple queues, congestion of host/starget needs to be handled
1474 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1481 * Kill a request for a dead device
1483 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1485 struct scsi_cmnd
*cmd
= req
->special
;
1486 struct scsi_device
*sdev
;
1487 struct scsi_target
*starget
;
1488 struct Scsi_Host
*shost
;
1490 blk_start_request(req
);
1492 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1495 starget
= scsi_target(sdev
);
1497 scsi_init_cmd_errh(cmd
);
1498 cmd
->result
= DID_NO_CONNECT
<< 16;
1499 atomic_inc(&cmd
->device
->iorequest_cnt
);
1502 * SCSI request completion path will do scsi_device_unbusy(),
1503 * bump busy counts. To bump the counters, we need to dance
1504 * with the locks as normal issue path does.
1506 sdev
->device_busy
++;
1507 spin_unlock(sdev
->request_queue
->queue_lock
);
1508 spin_lock(shost
->host_lock
);
1510 starget
->target_busy
++;
1511 spin_unlock(shost
->host_lock
);
1512 spin_lock(sdev
->request_queue
->queue_lock
);
1514 blk_complete_request(req
);
1517 static void scsi_softirq_done(struct request
*rq
)
1519 struct scsi_cmnd
*cmd
= rq
->special
;
1520 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1523 INIT_LIST_HEAD(&cmd
->eh_entry
);
1525 atomic_inc(&cmd
->device
->iodone_cnt
);
1527 atomic_inc(&cmd
->device
->ioerr_cnt
);
1529 disposition
= scsi_decide_disposition(cmd
);
1530 if (disposition
!= SUCCESS
&&
1531 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1532 sdev_printk(KERN_ERR
, cmd
->device
,
1533 "timing out command, waited %lus\n",
1535 disposition
= SUCCESS
;
1538 scsi_log_completion(cmd
, disposition
);
1540 switch (disposition
) {
1542 scsi_finish_command(cmd
);
1545 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1547 case ADD_TO_MLQUEUE
:
1548 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1551 if (!scsi_eh_scmd_add(cmd
, 0))
1552 scsi_finish_command(cmd
);
1557 * Function: scsi_request_fn()
1559 * Purpose: Main strategy routine for SCSI.
1561 * Arguments: q - Pointer to actual queue.
1565 * Lock status: IO request lock assumed to be held when called.
1567 static void scsi_request_fn(struct request_queue
*q
)
1569 struct scsi_device
*sdev
= q
->queuedata
;
1570 struct Scsi_Host
*shost
;
1571 struct scsi_cmnd
*cmd
;
1572 struct request
*req
;
1574 if(!get_device(&sdev
->sdev_gendev
))
1575 /* We must be tearing the block queue down already */
1579 * To start with, we keep looping until the queue is empty, or until
1580 * the host is no longer able to accept any more requests.
1586 * get next queueable request. We do this early to make sure
1587 * that the request is fully prepared even if we cannot
1590 req
= blk_peek_request(q
);
1591 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1594 if (unlikely(!scsi_device_online(sdev
))) {
1595 sdev_printk(KERN_ERR
, sdev
,
1596 "rejecting I/O to offline device\n");
1597 scsi_kill_request(req
, q
);
1603 * Remove the request from the request list.
1605 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1606 blk_start_request(req
);
1607 sdev
->device_busy
++;
1609 spin_unlock(q
->queue_lock
);
1611 if (unlikely(cmd
== NULL
)) {
1612 printk(KERN_CRIT
"impossible request in %s.\n"
1613 "please mail a stack trace to "
1614 "linux-scsi@vger.kernel.org\n",
1616 blk_dump_rq_flags(req
, "foo");
1619 spin_lock(shost
->host_lock
);
1622 * We hit this when the driver is using a host wide
1623 * tag map. For device level tag maps the queue_depth check
1624 * in the device ready fn would prevent us from trying
1625 * to allocate a tag. Since the map is a shared host resource
1626 * we add the dev to the starved list so it eventually gets
1627 * a run when a tag is freed.
1629 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1630 if (list_empty(&sdev
->starved_entry
))
1631 list_add_tail(&sdev
->starved_entry
,
1632 &shost
->starved_list
);
1636 if (!scsi_target_queue_ready(shost
, sdev
))
1639 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1642 scsi_target(sdev
)->target_busy
++;
1646 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1647 * take the lock again.
1649 spin_unlock_irq(shost
->host_lock
);
1652 * Finally, initialize any error handling parameters, and set up
1653 * the timers for timeouts.
1655 scsi_init_cmd_errh(cmd
);
1658 * Dispatch the command to the low-level driver.
1660 rtn
= scsi_dispatch_cmd(cmd
);
1661 spin_lock_irq(q
->queue_lock
);
1669 spin_unlock_irq(shost
->host_lock
);
1672 * lock q, handle tag, requeue req, and decrement device_busy. We
1673 * must return with queue_lock held.
1675 * Decrementing device_busy without checking it is OK, as all such
1676 * cases (host limits or settings) should run the queue at some
1679 spin_lock_irq(q
->queue_lock
);
1680 blk_requeue_request(q
, req
);
1681 sdev
->device_busy
--;
1683 if (sdev
->device_busy
== 0)
1684 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1686 /* must be careful here...if we trigger the ->remove() function
1687 * we cannot be holding the q lock */
1688 spin_unlock_irq(q
->queue_lock
);
1689 put_device(&sdev
->sdev_gendev
);
1690 spin_lock_irq(q
->queue_lock
);
1693 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1695 struct device
*host_dev
;
1696 u64 bounce_limit
= 0xffffffff;
1698 if (shost
->unchecked_isa_dma
)
1699 return BLK_BOUNCE_ISA
;
1701 * Platforms with virtual-DMA translation
1702 * hardware have no practical limit.
1704 if (!PCI_DMA_BUS_IS_PHYS
)
1705 return BLK_BOUNCE_ANY
;
1707 host_dev
= scsi_get_device(shost
);
1708 if (host_dev
&& host_dev
->dma_mask
)
1709 bounce_limit
= *host_dev
->dma_mask
;
1711 return bounce_limit
;
1713 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1715 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1716 request_fn_proc
*request_fn
)
1718 struct request_queue
*q
;
1719 struct device
*dev
= shost
->dma_dev
;
1721 q
= blk_init_queue(request_fn
, NULL
);
1726 * this limit is imposed by hardware restrictions
1728 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
1729 SCSI_MAX_SG_CHAIN_SEGMENTS
));
1731 if (scsi_host_prot_dma(shost
)) {
1732 shost
->sg_prot_tablesize
=
1733 min_not_zero(shost
->sg_prot_tablesize
,
1734 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
1735 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
1736 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
1739 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
1740 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1741 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1742 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1744 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1746 if (!shost
->use_clustering
)
1747 q
->limits
.cluster
= 0;
1750 * set a reasonable default alignment on word boundaries: the
1751 * host and device may alter it using
1752 * blk_queue_update_dma_alignment() later.
1754 blk_queue_dma_alignment(q
, 0x03);
1758 EXPORT_SYMBOL(__scsi_alloc_queue
);
1760 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1762 struct request_queue
*q
;
1764 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1768 blk_queue_prep_rq(q
, scsi_prep_fn
);
1769 blk_queue_softirq_done(q
, scsi_softirq_done
);
1770 blk_queue_rq_timed_out(q
, scsi_times_out
);
1771 blk_queue_lld_busy(q
, scsi_lld_busy
);
1776 * Function: scsi_block_requests()
1778 * Purpose: Utility function used by low-level drivers to prevent further
1779 * commands from being queued to the device.
1781 * Arguments: shost - Host in question
1785 * Lock status: No locks are assumed held.
1787 * Notes: There is no timer nor any other means by which the requests
1788 * get unblocked other than the low-level driver calling
1789 * scsi_unblock_requests().
1791 void scsi_block_requests(struct Scsi_Host
*shost
)
1793 shost
->host_self_blocked
= 1;
1795 EXPORT_SYMBOL(scsi_block_requests
);
1798 * Function: scsi_unblock_requests()
1800 * Purpose: Utility function used by low-level drivers to allow further
1801 * commands from being queued to the device.
1803 * Arguments: shost - Host in question
1807 * Lock status: No locks are assumed held.
1809 * Notes: There is no timer nor any other means by which the requests
1810 * get unblocked other than the low-level driver calling
1811 * scsi_unblock_requests().
1813 * This is done as an API function so that changes to the
1814 * internals of the scsi mid-layer won't require wholesale
1815 * changes to drivers that use this feature.
1817 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1819 shost
->host_self_blocked
= 0;
1820 scsi_run_host_queues(shost
);
1822 EXPORT_SYMBOL(scsi_unblock_requests
);
1824 int __init
scsi_init_queue(void)
1828 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1829 sizeof(struct scsi_data_buffer
),
1831 if (!scsi_sdb_cache
) {
1832 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1836 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1837 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1838 int size
= sgp
->size
* sizeof(struct scatterlist
);
1840 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1841 SLAB_HWCACHE_ALIGN
, NULL
);
1843 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1848 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1851 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1860 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1861 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1863 mempool_destroy(sgp
->pool
);
1865 kmem_cache_destroy(sgp
->slab
);
1867 kmem_cache_destroy(scsi_sdb_cache
);
1872 void scsi_exit_queue(void)
1876 kmem_cache_destroy(scsi_sdb_cache
);
1878 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1879 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1880 mempool_destroy(sgp
->pool
);
1881 kmem_cache_destroy(sgp
->slab
);
1886 * scsi_mode_select - issue a mode select
1887 * @sdev: SCSI device to be queried
1888 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1889 * @sp: Save page bit (0 == don't save, 1 == save)
1890 * @modepage: mode page being requested
1891 * @buffer: request buffer (may not be smaller than eight bytes)
1892 * @len: length of request buffer.
1893 * @timeout: command timeout
1894 * @retries: number of retries before failing
1895 * @data: returns a structure abstracting the mode header data
1896 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1897 * must be SCSI_SENSE_BUFFERSIZE big.
1899 * Returns zero if successful; negative error number or scsi
1904 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1905 unsigned char *buffer
, int len
, int timeout
, int retries
,
1906 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1908 unsigned char cmd
[10];
1909 unsigned char *real_buffer
;
1912 memset(cmd
, 0, sizeof(cmd
));
1913 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1915 if (sdev
->use_10_for_ms
) {
1918 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1921 memcpy(real_buffer
+ 8, buffer
, len
);
1925 real_buffer
[2] = data
->medium_type
;
1926 real_buffer
[3] = data
->device_specific
;
1927 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1929 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1930 real_buffer
[7] = data
->block_descriptor_length
;
1932 cmd
[0] = MODE_SELECT_10
;
1936 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1940 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1943 memcpy(real_buffer
+ 4, buffer
, len
);
1946 real_buffer
[1] = data
->medium_type
;
1947 real_buffer
[2] = data
->device_specific
;
1948 real_buffer
[3] = data
->block_descriptor_length
;
1951 cmd
[0] = MODE_SELECT
;
1955 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1956 sshdr
, timeout
, retries
, NULL
);
1960 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1963 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1964 * @sdev: SCSI device to be queried
1965 * @dbd: set if mode sense will allow block descriptors to be returned
1966 * @modepage: mode page being requested
1967 * @buffer: request buffer (may not be smaller than eight bytes)
1968 * @len: length of request buffer.
1969 * @timeout: command timeout
1970 * @retries: number of retries before failing
1971 * @data: returns a structure abstracting the mode header data
1972 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1973 * must be SCSI_SENSE_BUFFERSIZE big.
1975 * Returns zero if unsuccessful, or the header offset (either 4
1976 * or 8 depending on whether a six or ten byte command was
1977 * issued) if successful.
1980 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1981 unsigned char *buffer
, int len
, int timeout
, int retries
,
1982 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1984 unsigned char cmd
[12];
1988 struct scsi_sense_hdr my_sshdr
;
1990 memset(data
, 0, sizeof(*data
));
1991 memset(&cmd
[0], 0, 12);
1992 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1995 /* caller might not be interested in sense, but we need it */
2000 use_10_for_ms
= sdev
->use_10_for_ms
;
2002 if (use_10_for_ms
) {
2006 cmd
[0] = MODE_SENSE_10
;
2013 cmd
[0] = MODE_SENSE
;
2018 memset(buffer
, 0, len
);
2020 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2021 sshdr
, timeout
, retries
, NULL
);
2023 /* This code looks awful: what it's doing is making sure an
2024 * ILLEGAL REQUEST sense return identifies the actual command
2025 * byte as the problem. MODE_SENSE commands can return
2026 * ILLEGAL REQUEST if the code page isn't supported */
2028 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2029 (driver_byte(result
) & DRIVER_SENSE
)) {
2030 if (scsi_sense_valid(sshdr
)) {
2031 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2032 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2034 * Invalid command operation code
2036 sdev
->use_10_for_ms
= 0;
2042 if(scsi_status_is_good(result
)) {
2043 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2044 (modepage
== 6 || modepage
== 8))) {
2045 /* Initio breakage? */
2048 data
->medium_type
= 0;
2049 data
->device_specific
= 0;
2051 data
->block_descriptor_length
= 0;
2052 } else if(use_10_for_ms
) {
2053 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2054 data
->medium_type
= buffer
[2];
2055 data
->device_specific
= buffer
[3];
2056 data
->longlba
= buffer
[4] & 0x01;
2057 data
->block_descriptor_length
= buffer
[6]*256
2060 data
->length
= buffer
[0] + 1;
2061 data
->medium_type
= buffer
[1];
2062 data
->device_specific
= buffer
[2];
2063 data
->block_descriptor_length
= buffer
[3];
2065 data
->header_length
= header_length
;
2070 EXPORT_SYMBOL(scsi_mode_sense
);
2073 * scsi_test_unit_ready - test if unit is ready
2074 * @sdev: scsi device to change the state of.
2075 * @timeout: command timeout
2076 * @retries: number of retries before failing
2077 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2078 * returning sense. Make sure that this is cleared before passing
2081 * Returns zero if unsuccessful or an error if TUR failed. For
2082 * removable media, UNIT_ATTENTION sets ->changed flag.
2085 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2086 struct scsi_sense_hdr
*sshdr_external
)
2089 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2091 struct scsi_sense_hdr
*sshdr
;
2094 if (!sshdr_external
)
2095 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2097 sshdr
= sshdr_external
;
2099 /* try to eat the UNIT_ATTENTION if there are enough retries */
2101 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2102 timeout
, retries
, NULL
);
2103 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2104 sshdr
->sense_key
== UNIT_ATTENTION
)
2106 } while (scsi_sense_valid(sshdr
) &&
2107 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2109 if (!sshdr_external
)
2113 EXPORT_SYMBOL(scsi_test_unit_ready
);
2116 * scsi_device_set_state - Take the given device through the device state model.
2117 * @sdev: scsi device to change the state of.
2118 * @state: state to change to.
2120 * Returns zero if unsuccessful or an error if the requested
2121 * transition is illegal.
2124 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2126 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2128 if (state
== oldstate
)
2134 case SDEV_CREATED_BLOCK
:
2145 case SDEV_TRANSPORT_OFFLINE
:
2158 case SDEV_TRANSPORT_OFFLINE
:
2166 case SDEV_TRANSPORT_OFFLINE
:
2181 case SDEV_CREATED_BLOCK
:
2188 case SDEV_CREATED_BLOCK
:
2203 case SDEV_TRANSPORT_OFFLINE
:
2216 case SDEV_TRANSPORT_OFFLINE
:
2218 case SDEV_CREATED_BLOCK
:
2226 sdev
->sdev_state
= state
;
2230 SCSI_LOG_ERROR_RECOVERY(1,
2231 sdev_printk(KERN_ERR
, sdev
,
2232 "Illegal state transition %s->%s\n",
2233 scsi_device_state_name(oldstate
),
2234 scsi_device_state_name(state
))
2238 EXPORT_SYMBOL(scsi_device_set_state
);
2241 * sdev_evt_emit - emit a single SCSI device uevent
2242 * @sdev: associated SCSI device
2243 * @evt: event to emit
2245 * Send a single uevent (scsi_event) to the associated scsi_device.
2247 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2252 switch (evt
->evt_type
) {
2253 case SDEV_EVT_MEDIA_CHANGE
:
2254 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2256 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2257 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2259 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2260 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2262 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2263 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2265 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2266 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2268 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2269 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2278 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2282 * sdev_evt_thread - send a uevent for each scsi event
2283 * @work: work struct for scsi_device
2285 * Dispatch queued events to their associated scsi_device kobjects
2288 void scsi_evt_thread(struct work_struct
*work
)
2290 struct scsi_device
*sdev
;
2291 enum scsi_device_event evt_type
;
2292 LIST_HEAD(event_list
);
2294 sdev
= container_of(work
, struct scsi_device
, event_work
);
2296 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2297 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2298 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2301 struct scsi_event
*evt
;
2302 struct list_head
*this, *tmp
;
2303 unsigned long flags
;
2305 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2306 list_splice_init(&sdev
->event_list
, &event_list
);
2307 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2309 if (list_empty(&event_list
))
2312 list_for_each_safe(this, tmp
, &event_list
) {
2313 evt
= list_entry(this, struct scsi_event
, node
);
2314 list_del(&evt
->node
);
2315 scsi_evt_emit(sdev
, evt
);
2322 * sdev_evt_send - send asserted event to uevent thread
2323 * @sdev: scsi_device event occurred on
2324 * @evt: event to send
2326 * Assert scsi device event asynchronously.
2328 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2330 unsigned long flags
;
2333 /* FIXME: currently this check eliminates all media change events
2334 * for polled devices. Need to update to discriminate between AN
2335 * and polled events */
2336 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2342 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2343 list_add_tail(&evt
->node
, &sdev
->event_list
);
2344 schedule_work(&sdev
->event_work
);
2345 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2347 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2350 * sdev_evt_alloc - allocate a new scsi event
2351 * @evt_type: type of event to allocate
2352 * @gfpflags: GFP flags for allocation
2354 * Allocates and returns a new scsi_event.
2356 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2359 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2363 evt
->evt_type
= evt_type
;
2364 INIT_LIST_HEAD(&evt
->node
);
2366 /* evt_type-specific initialization, if any */
2368 case SDEV_EVT_MEDIA_CHANGE
:
2369 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2370 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2371 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2372 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2373 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2381 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2384 * sdev_evt_send_simple - send asserted event to uevent thread
2385 * @sdev: scsi_device event occurred on
2386 * @evt_type: type of event to send
2387 * @gfpflags: GFP flags for allocation
2389 * Assert scsi device event asynchronously, given an event type.
2391 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2392 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2394 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2396 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2401 sdev_evt_send(sdev
, evt
);
2403 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2406 * scsi_device_quiesce - Block user issued commands.
2407 * @sdev: scsi device to quiesce.
2409 * This works by trying to transition to the SDEV_QUIESCE state
2410 * (which must be a legal transition). When the device is in this
2411 * state, only special requests will be accepted, all others will
2412 * be deferred. Since special requests may also be requeued requests,
2413 * a successful return doesn't guarantee the device will be
2414 * totally quiescent.
2416 * Must be called with user context, may sleep.
2418 * Returns zero if unsuccessful or an error if not.
2421 scsi_device_quiesce(struct scsi_device
*sdev
)
2423 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2427 scsi_run_queue(sdev
->request_queue
);
2428 while (sdev
->device_busy
) {
2429 msleep_interruptible(200);
2430 scsi_run_queue(sdev
->request_queue
);
2434 EXPORT_SYMBOL(scsi_device_quiesce
);
2437 * scsi_device_resume - Restart user issued commands to a quiesced device.
2438 * @sdev: scsi device to resume.
2440 * Moves the device from quiesced back to running and restarts the
2443 * Must be called with user context, may sleep.
2445 void scsi_device_resume(struct scsi_device
*sdev
)
2447 /* check if the device state was mutated prior to resume, and if
2448 * so assume the state is being managed elsewhere (for example
2449 * device deleted during suspend)
2451 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2452 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2454 scsi_run_queue(sdev
->request_queue
);
2456 EXPORT_SYMBOL(scsi_device_resume
);
2459 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2461 scsi_device_quiesce(sdev
);
2465 scsi_target_quiesce(struct scsi_target
*starget
)
2467 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2469 EXPORT_SYMBOL(scsi_target_quiesce
);
2472 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2474 scsi_device_resume(sdev
);
2478 scsi_target_resume(struct scsi_target
*starget
)
2480 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2482 EXPORT_SYMBOL(scsi_target_resume
);
2485 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2486 * @sdev: device to block
2488 * Block request made by scsi lld's to temporarily stop all
2489 * scsi commands on the specified device. Called from interrupt
2490 * or normal process context.
2492 * Returns zero if successful or error if not
2495 * This routine transitions the device to the SDEV_BLOCK state
2496 * (which must be a legal transition). When the device is in this
2497 * state, all commands are deferred until the scsi lld reenables
2498 * the device with scsi_device_unblock or device_block_tmo fires.
2501 scsi_internal_device_block(struct scsi_device
*sdev
)
2503 struct request_queue
*q
= sdev
->request_queue
;
2504 unsigned long flags
;
2507 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2509 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2516 * The device has transitioned to SDEV_BLOCK. Stop the
2517 * block layer from calling the midlayer with this device's
2520 spin_lock_irqsave(q
->queue_lock
, flags
);
2522 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2526 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2529 * scsi_internal_device_unblock - resume a device after a block request
2530 * @sdev: device to resume
2531 * @new_state: state to set devices to after unblocking
2533 * Called by scsi lld's or the midlayer to restart the device queue
2534 * for the previously suspended scsi device. Called from interrupt or
2535 * normal process context.
2537 * Returns zero if successful or error if not.
2540 * This routine transitions the device to the SDEV_RUNNING state
2541 * or to one of the offline states (which must be a legal transition)
2542 * allowing the midlayer to goose the queue for this device.
2545 scsi_internal_device_unblock(struct scsi_device
*sdev
,
2546 enum scsi_device_state new_state
)
2548 struct request_queue
*q
= sdev
->request_queue
;
2549 unsigned long flags
;
2552 * Try to transition the scsi device to SDEV_RUNNING or one of the
2553 * offlined states and goose the device queue if successful.
2555 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
2556 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
2557 sdev
->sdev_state
= new_state
;
2558 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
2559 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
2560 new_state
== SDEV_OFFLINE
)
2561 sdev
->sdev_state
= new_state
;
2563 sdev
->sdev_state
= SDEV_CREATED
;
2564 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
2565 sdev
->sdev_state
!= SDEV_OFFLINE
)
2568 spin_lock_irqsave(q
->queue_lock
, flags
);
2570 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2574 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2577 device_block(struct scsi_device
*sdev
, void *data
)
2579 scsi_internal_device_block(sdev
);
2583 target_block(struct device
*dev
, void *data
)
2585 if (scsi_is_target_device(dev
))
2586 starget_for_each_device(to_scsi_target(dev
), NULL
,
2592 scsi_target_block(struct device
*dev
)
2594 if (scsi_is_target_device(dev
))
2595 starget_for_each_device(to_scsi_target(dev
), NULL
,
2598 device_for_each_child(dev
, NULL
, target_block
);
2600 EXPORT_SYMBOL_GPL(scsi_target_block
);
2603 device_unblock(struct scsi_device
*sdev
, void *data
)
2605 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
2609 target_unblock(struct device
*dev
, void *data
)
2611 if (scsi_is_target_device(dev
))
2612 starget_for_each_device(to_scsi_target(dev
), data
,
2618 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
2620 if (scsi_is_target_device(dev
))
2621 starget_for_each_device(to_scsi_target(dev
), &new_state
,
2624 device_for_each_child(dev
, &new_state
, target_unblock
);
2626 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2629 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2630 * @sgl: scatter-gather list
2631 * @sg_count: number of segments in sg
2632 * @offset: offset in bytes into sg, on return offset into the mapped area
2633 * @len: bytes to map, on return number of bytes mapped
2635 * Returns virtual address of the start of the mapped page
2637 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2638 size_t *offset
, size_t *len
)
2641 size_t sg_len
= 0, len_complete
= 0;
2642 struct scatterlist
*sg
;
2645 WARN_ON(!irqs_disabled());
2647 for_each_sg(sgl
, sg
, sg_count
, i
) {
2648 len_complete
= sg_len
; /* Complete sg-entries */
2649 sg_len
+= sg
->length
;
2650 if (sg_len
> *offset
)
2654 if (unlikely(i
== sg_count
)) {
2655 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2657 __func__
, sg_len
, *offset
, sg_count
);
2662 /* Offset starting from the beginning of first page in this sg-entry */
2663 *offset
= *offset
- len_complete
+ sg
->offset
;
2665 /* Assumption: contiguous pages can be accessed as "page + i" */
2666 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2667 *offset
&= ~PAGE_MASK
;
2669 /* Bytes in this sg-entry from *offset to the end of the page */
2670 sg_len
= PAGE_SIZE
- *offset
;
2674 return kmap_atomic(page
);
2676 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2679 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2680 * @virt: virtual address to be unmapped
2682 void scsi_kunmap_atomic_sg(void *virt
)
2684 kunmap_atomic(virt
);
2686 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
2688 void sdev_disable_disk_events(struct scsi_device
*sdev
)
2690 atomic_inc(&sdev
->disk_events_disable_depth
);
2692 EXPORT_SYMBOL(sdev_disable_disk_events
);
2694 void sdev_enable_disk_events(struct scsi_device
*sdev
)
2696 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
2698 atomic_dec(&sdev
->disk_events_disable_depth
);
2700 EXPORT_SYMBOL(sdev_enable_disk_events
);