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/blkdev.h>
12 #include <linux/completion.h>
13 #include <linux/kernel.h>
14 #include <linux/mempool.h>
15 #include <linux/slab.h>
16 #include <linux/init.h>
17 #include <linux/pci.h>
18 #include <linux/delay.h>
19 #include <linux/hardirq.h>
21 #include <scsi/scsi.h>
22 #include <scsi/scsi_cmnd.h>
23 #include <scsi/scsi_dbg.h>
24 #include <scsi/scsi_device.h>
25 #include <scsi/scsi_driver.h>
26 #include <scsi/scsi_eh.h>
27 #include <scsi/scsi_host.h>
29 #include "scsi_priv.h"
30 #include "scsi_logging.h"
33 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
34 #define SG_MEMPOOL_SIZE 32
36 struct scsi_host_sg_pool
{
39 struct kmem_cache
*slab
;
43 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
44 #error SCSI_MAX_PHYS_SEGMENTS is too small
47 #define SP(x) { x, "sgpool-" #x }
48 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
52 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
54 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
56 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
58 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
59 #error SCSI_MAX_PHYS_SEGMENTS is too large
67 static void scsi_run_queue(struct request_queue
*q
);
70 * Function: scsi_unprep_request()
72 * Purpose: Remove all preparation done for a request, including its
73 * associated scsi_cmnd, so that it can be requeued.
75 * Arguments: req - request to unprepare
77 * Lock status: Assumed that no locks are held upon entry.
81 static void scsi_unprep_request(struct request
*req
)
83 struct scsi_cmnd
*cmd
= req
->special
;
85 req
->cmd_flags
&= ~REQ_DONTPREP
;
88 scsi_put_command(cmd
);
92 * Function: scsi_queue_insert()
94 * Purpose: Insert a command in the midlevel queue.
96 * Arguments: cmd - command that we are adding to queue.
97 * reason - why we are inserting command to queue.
99 * Lock status: Assumed that lock is not held upon entry.
103 * Notes: We do this for one of two cases. Either the host is busy
104 * and it cannot accept any more commands for the time being,
105 * or the device returned QUEUE_FULL and can accept no more
107 * Notes: This could be called either from an interrupt context or a
108 * normal process context.
110 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
112 struct Scsi_Host
*host
= cmd
->device
->host
;
113 struct scsi_device
*device
= cmd
->device
;
114 struct request_queue
*q
= device
->request_queue
;
118 printk("Inserting command %p into mlqueue\n", cmd
));
121 * Set the appropriate busy bit for the device/host.
123 * If the host/device isn't busy, assume that something actually
124 * completed, and that we should be able to queue a command now.
126 * Note that the prior mid-layer assumption that any host could
127 * always queue at least one command is now broken. The mid-layer
128 * will implement a user specifiable stall (see
129 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
130 * if a command is requeued with no other commands outstanding
131 * either for the device or for the host.
133 if (reason
== SCSI_MLQUEUE_HOST_BUSY
)
134 host
->host_blocked
= host
->max_host_blocked
;
135 else if (reason
== SCSI_MLQUEUE_DEVICE_BUSY
)
136 device
->device_blocked
= device
->max_device_blocked
;
139 * Decrement the counters, since these commands are no longer
140 * active on the host/device.
142 scsi_device_unbusy(device
);
145 * Requeue this command. It will go before all other commands
146 * that are already in the queue.
148 * NOTE: there is magic here about the way the queue is plugged if
149 * we have no outstanding commands.
151 * Although we *don't* plug the queue, we call the request
152 * function. The SCSI request function detects the blocked condition
153 * and plugs the queue appropriately.
155 spin_lock_irqsave(q
->queue_lock
, flags
);
156 blk_requeue_request(q
, cmd
->request
);
157 spin_unlock_irqrestore(q
->queue_lock
, flags
);
165 * scsi_execute - insert request and wait for the result
168 * @data_direction: data direction
169 * @buffer: data buffer
170 * @bufflen: len of buffer
171 * @sense: optional sense buffer
172 * @timeout: request timeout in seconds
173 * @retries: number of times to retry request
174 * @flags: or into request flags;
176 * returns the req->errors value which is the the scsi_cmnd result
179 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
180 int data_direction
, void *buffer
, unsigned bufflen
,
181 unsigned char *sense
, int timeout
, int retries
, int flags
)
184 int write
= (data_direction
== DMA_TO_DEVICE
);
185 int ret
= DRIVER_ERROR
<< 24;
187 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
189 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
190 buffer
, bufflen
, __GFP_WAIT
))
193 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
194 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
197 req
->retries
= retries
;
198 req
->timeout
= timeout
;
199 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
200 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
203 * head injection *required* here otherwise quiesce won't work
205 blk_execute_rq(req
->q
, NULL
, req
, 1);
209 blk_put_request(req
);
213 EXPORT_SYMBOL(scsi_execute
);
216 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
217 int data_direction
, void *buffer
, unsigned bufflen
,
218 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
224 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
226 return DRIVER_ERROR
<< 24;
228 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
229 sense
, timeout
, retries
, 0);
231 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
236 EXPORT_SYMBOL(scsi_execute_req
);
238 struct scsi_io_context
{
240 void (*done
)(void *data
, char *sense
, int result
, int resid
);
241 char sense
[SCSI_SENSE_BUFFERSIZE
];
244 static struct kmem_cache
*scsi_io_context_cache
;
246 static void scsi_end_async(struct request
*req
, int uptodate
)
248 struct scsi_io_context
*sioc
= req
->end_io_data
;
251 sioc
->done(sioc
->data
, sioc
->sense
, req
->errors
, req
->data_len
);
253 kmem_cache_free(scsi_io_context_cache
, sioc
);
254 __blk_put_request(req
->q
, req
);
257 static int scsi_merge_bio(struct request
*rq
, struct bio
*bio
)
259 struct request_queue
*q
= rq
->q
;
261 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
262 if (rq_data_dir(rq
) == WRITE
)
263 bio
->bi_rw
|= (1 << BIO_RW
);
264 blk_queue_bounce(q
, &bio
);
267 blk_rq_bio_prep(q
, rq
, bio
);
268 else if (!ll_back_merge_fn(q
, rq
, bio
))
271 rq
->biotail
->bi_next
= bio
;
278 static int scsi_bi_endio(struct bio
*bio
, unsigned int bytes_done
, int error
)
288 * scsi_req_map_sg - map a scatterlist into a request
289 * @rq: request to fill
291 * @nsegs: number of elements
292 * @bufflen: len of buffer
293 * @gfp: memory allocation flags
295 * scsi_req_map_sg maps a scatterlist into a request so that the
296 * request can be sent to the block layer. We do not trust the scatterlist
297 * sent to use, as some ULDs use that struct to only organize the pages.
299 static int scsi_req_map_sg(struct request
*rq
, struct scatterlist
*sgl
,
300 int nsegs
, unsigned bufflen
, gfp_t gfp
)
302 struct request_queue
*q
= rq
->q
;
303 int nr_pages
= (bufflen
+ sgl
[0].offset
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
304 unsigned int data_len
= 0, len
, bytes
, off
;
306 struct bio
*bio
= NULL
;
307 int i
, err
, nr_vecs
= 0;
309 for (i
= 0; i
< nsegs
; i
++) {
316 bytes
= min_t(unsigned int, len
, PAGE_SIZE
- off
);
319 nr_vecs
= min_t(int, BIO_MAX_PAGES
, nr_pages
);
322 bio
= bio_alloc(gfp
, nr_vecs
);
327 bio
->bi_end_io
= scsi_bi_endio
;
330 if (bio_add_pc_page(q
, bio
, page
, bytes
, off
) !=
337 if (bio
->bi_vcnt
>= nr_vecs
) {
338 err
= scsi_merge_bio(rq
, bio
);
340 bio_endio(bio
, bio
->bi_size
, 0);
352 rq
->buffer
= rq
->data
= NULL
;
353 rq
->data_len
= data_len
;
357 while ((bio
= rq
->bio
) != NULL
) {
358 rq
->bio
= bio
->bi_next
;
360 * call endio instead of bio_put incase it was bounced
362 bio_endio(bio
, bio
->bi_size
, 0);
369 * scsi_execute_async - insert request
372 * @cmd_len: length of scsi cdb
373 * @data_direction: data direction
374 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
375 * @bufflen: len of buffer
376 * @use_sg: if buffer is a scatterlist this is the number of elements
377 * @timeout: request timeout in seconds
378 * @retries: number of times to retry request
379 * @flags: or into request flags
381 int scsi_execute_async(struct scsi_device
*sdev
, const unsigned char *cmd
,
382 int cmd_len
, int data_direction
, void *buffer
, unsigned bufflen
,
383 int use_sg
, int timeout
, int retries
, void *privdata
,
384 void (*done
)(void *, char *, int, int), gfp_t gfp
)
387 struct scsi_io_context
*sioc
;
389 int write
= (data_direction
== DMA_TO_DEVICE
);
391 sioc
= kmem_cache_alloc(scsi_io_context_cache
, gfp
);
393 return DRIVER_ERROR
<< 24;
394 memset(sioc
, 0, sizeof(*sioc
));
396 req
= blk_get_request(sdev
->request_queue
, write
, gfp
);
399 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
400 req
->cmd_flags
|= REQ_QUIET
;
403 err
= scsi_req_map_sg(req
, buffer
, use_sg
, bufflen
, gfp
);
405 err
= blk_rq_map_kern(req
->q
, req
, buffer
, bufflen
, gfp
);
410 req
->cmd_len
= cmd_len
;
411 memset(req
->cmd
, 0, BLK_MAX_CDB
); /* ATAPI hates garbage after CDB */
412 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
413 req
->sense
= sioc
->sense
;
415 req
->timeout
= timeout
;
416 req
->retries
= retries
;
417 req
->end_io_data
= sioc
;
419 sioc
->data
= privdata
;
422 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
426 blk_put_request(req
);
428 kmem_cache_free(scsi_io_context_cache
, sioc
);
429 return DRIVER_ERROR
<< 24;
431 EXPORT_SYMBOL_GPL(scsi_execute_async
);
434 * Function: scsi_init_cmd_errh()
436 * Purpose: Initialize cmd fields related to error handling.
438 * Arguments: cmd - command that is ready to be queued.
440 * Notes: This function has the job of initializing a number of
441 * fields related to error handling. Typically this will
442 * be called once for each command, as required.
444 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
446 cmd
->serial_number
= 0;
447 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
448 if (cmd
->cmd_len
== 0)
449 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
452 void scsi_device_unbusy(struct scsi_device
*sdev
)
454 struct Scsi_Host
*shost
= sdev
->host
;
457 spin_lock_irqsave(shost
->host_lock
, flags
);
459 if (unlikely(scsi_host_in_recovery(shost
) &&
460 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
461 scsi_eh_wakeup(shost
);
462 spin_unlock(shost
->host_lock
);
463 spin_lock(sdev
->request_queue
->queue_lock
);
465 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
469 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
470 * and call blk_run_queue for all the scsi_devices on the target -
471 * including current_sdev first.
473 * Called with *no* scsi locks held.
475 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
477 struct Scsi_Host
*shost
= current_sdev
->host
;
478 struct scsi_device
*sdev
, *tmp
;
479 struct scsi_target
*starget
= scsi_target(current_sdev
);
482 spin_lock_irqsave(shost
->host_lock
, flags
);
483 starget
->starget_sdev_user
= NULL
;
484 spin_unlock_irqrestore(shost
->host_lock
, flags
);
487 * Call blk_run_queue for all LUNs on the target, starting with
488 * current_sdev. We race with others (to set starget_sdev_user),
489 * but in most cases, we will be first. Ideally, each LU on the
490 * target would get some limited time or requests on the target.
492 blk_run_queue(current_sdev
->request_queue
);
494 spin_lock_irqsave(shost
->host_lock
, flags
);
495 if (starget
->starget_sdev_user
)
497 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
498 same_target_siblings
) {
499 if (sdev
== current_sdev
)
501 if (scsi_device_get(sdev
))
504 spin_unlock_irqrestore(shost
->host_lock
, flags
);
505 blk_run_queue(sdev
->request_queue
);
506 spin_lock_irqsave(shost
->host_lock
, flags
);
508 scsi_device_put(sdev
);
511 spin_unlock_irqrestore(shost
->host_lock
, flags
);
515 * Function: scsi_run_queue()
517 * Purpose: Select a proper request queue to serve next
519 * Arguments: q - last request's queue
523 * Notes: The previous command was completely finished, start
524 * a new one if possible.
526 static void scsi_run_queue(struct request_queue
*q
)
528 struct scsi_device
*sdev
= q
->queuedata
;
529 struct Scsi_Host
*shost
= sdev
->host
;
532 if (sdev
->single_lun
)
533 scsi_single_lun_run(sdev
);
535 spin_lock_irqsave(shost
->host_lock
, flags
);
536 while (!list_empty(&shost
->starved_list
) &&
537 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
538 !((shost
->can_queue
> 0) &&
539 (shost
->host_busy
>= shost
->can_queue
))) {
541 * As long as shost is accepting commands and we have
542 * starved queues, call blk_run_queue. scsi_request_fn
543 * drops the queue_lock and can add us back to the
546 * host_lock protects the starved_list and starved_entry.
547 * scsi_request_fn must get the host_lock before checking
548 * or modifying starved_list or starved_entry.
550 sdev
= list_entry(shost
->starved_list
.next
,
551 struct scsi_device
, starved_entry
);
552 list_del_init(&sdev
->starved_entry
);
553 spin_unlock_irqrestore(shost
->host_lock
, flags
);
556 if (test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
557 !test_and_set_bit(QUEUE_FLAG_REENTER
,
558 &sdev
->request_queue
->queue_flags
)) {
559 blk_run_queue(sdev
->request_queue
);
560 clear_bit(QUEUE_FLAG_REENTER
,
561 &sdev
->request_queue
->queue_flags
);
563 blk_run_queue(sdev
->request_queue
);
565 spin_lock_irqsave(shost
->host_lock
, flags
);
566 if (unlikely(!list_empty(&sdev
->starved_entry
)))
568 * sdev lost a race, and was put back on the
569 * starved list. This is unlikely but without this
570 * in theory we could loop forever.
574 spin_unlock_irqrestore(shost
->host_lock
, flags
);
580 * Function: scsi_requeue_command()
582 * Purpose: Handle post-processing of completed commands.
584 * Arguments: q - queue to operate on
585 * cmd - command that may need to be requeued.
589 * Notes: After command completion, there may be blocks left
590 * over which weren't finished by the previous command
591 * this can be for a number of reasons - the main one is
592 * I/O errors in the middle of the request, in which case
593 * we need to request the blocks that come after the bad
595 * Notes: Upon return, cmd is a stale pointer.
597 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
599 struct request
*req
= cmd
->request
;
602 scsi_unprep_request(req
);
603 spin_lock_irqsave(q
->queue_lock
, flags
);
604 blk_requeue_request(q
, req
);
605 spin_unlock_irqrestore(q
->queue_lock
, flags
);
610 void scsi_next_command(struct scsi_cmnd
*cmd
)
612 struct scsi_device
*sdev
= cmd
->device
;
613 struct request_queue
*q
= sdev
->request_queue
;
615 /* need to hold a reference on the device before we let go of the cmd */
616 get_device(&sdev
->sdev_gendev
);
618 scsi_put_command(cmd
);
621 /* ok to remove device now */
622 put_device(&sdev
->sdev_gendev
);
625 void scsi_run_host_queues(struct Scsi_Host
*shost
)
627 struct scsi_device
*sdev
;
629 shost_for_each_device(sdev
, shost
)
630 scsi_run_queue(sdev
->request_queue
);
634 * Function: scsi_end_request()
636 * Purpose: Post-processing of completed commands (usually invoked at end
637 * of upper level post-processing and scsi_io_completion).
639 * Arguments: cmd - command that is complete.
640 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
641 * bytes - number of bytes of completed I/O
642 * requeue - indicates whether we should requeue leftovers.
644 * Lock status: Assumed that lock is not held upon entry.
646 * Returns: cmd if requeue required, NULL otherwise.
648 * Notes: This is called for block device requests in order to
649 * mark some number of sectors as complete.
651 * We are guaranteeing that the request queue will be goosed
652 * at some point during this call.
653 * Notes: If cmd was requeued, upon return it will be a stale pointer.
655 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
656 int bytes
, int requeue
)
658 request_queue_t
*q
= cmd
->device
->request_queue
;
659 struct request
*req
= cmd
->request
;
663 * If there are blocks left over at the end, set up the command
664 * to queue the remainder of them.
666 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
667 int leftover
= (req
->hard_nr_sectors
<< 9);
669 if (blk_pc_request(req
))
670 leftover
= req
->data_len
;
672 /* kill remainder if no retrys */
673 if (!uptodate
&& blk_noretry_request(req
))
674 end_that_request_chunk(req
, 0, leftover
);
678 * Bleah. Leftovers again. Stick the
679 * leftovers in the front of the
680 * queue, and goose the queue again.
682 scsi_requeue_command(q
, cmd
);
689 add_disk_randomness(req
->rq_disk
);
691 spin_lock_irqsave(q
->queue_lock
, flags
);
692 if (blk_rq_tagged(req
))
693 blk_queue_end_tag(q
, req
);
694 end_that_request_last(req
, uptodate
);
695 spin_unlock_irqrestore(q
->queue_lock
, flags
);
698 * This will goose the queue request function at the end, so we don't
699 * need to worry about launching another command.
701 scsi_next_command(cmd
);
705 struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
707 struct scsi_host_sg_pool
*sgp
;
708 struct scatterlist
*sgl
;
710 BUG_ON(!cmd
->use_sg
);
712 switch (cmd
->use_sg
) {
722 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
726 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
730 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
741 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
742 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
746 EXPORT_SYMBOL(scsi_alloc_sgtable
);
748 void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
750 struct scsi_host_sg_pool
*sgp
;
752 BUG_ON(index
>= SG_MEMPOOL_NR
);
754 sgp
= scsi_sg_pools
+ index
;
755 mempool_free(sgl
, sgp
->pool
);
758 EXPORT_SYMBOL(scsi_free_sgtable
);
761 * Function: scsi_release_buffers()
763 * Purpose: Completion processing for block device I/O requests.
765 * Arguments: cmd - command that we are bailing.
767 * Lock status: Assumed that no lock is held upon entry.
771 * Notes: In the event that an upper level driver rejects a
772 * command, we must release resources allocated during
773 * the __init_io() function. Primarily this would involve
774 * the scatter-gather table, and potentially any bounce
777 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
780 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
783 * Zero these out. They now point to freed memory, and it is
784 * dangerous to hang onto the pointers.
786 cmd
->request_buffer
= NULL
;
787 cmd
->request_bufflen
= 0;
791 * Function: scsi_io_completion()
793 * Purpose: Completion processing for block device I/O requests.
795 * Arguments: cmd - command that is finished.
797 * Lock status: Assumed that no lock is held upon entry.
801 * Notes: This function is matched in terms of capabilities to
802 * the function that created the scatter-gather list.
803 * In other words, if there are no bounce buffers
804 * (the normal case for most drivers), we don't need
805 * the logic to deal with cleaning up afterwards.
807 * We must do one of several things here:
809 * a) Call scsi_end_request. This will finish off the
810 * specified number of sectors. If we are done, the
811 * command block will be released, and the queue
812 * function will be goosed. If we are not done, then
813 * scsi_end_request will directly goose the queue.
815 * b) We can just use scsi_requeue_command() here. This would
816 * be used if we just wanted to retry, for example.
818 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
820 int result
= cmd
->result
;
821 int this_count
= cmd
->request_bufflen
;
822 request_queue_t
*q
= cmd
->device
->request_queue
;
823 struct request
*req
= cmd
->request
;
824 int clear_errors
= 1;
825 struct scsi_sense_hdr sshdr
;
827 int sense_deferred
= 0;
829 scsi_release_buffers(cmd
);
832 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
834 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
837 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
838 req
->errors
= result
;
841 if (sense_valid
&& req
->sense
) {
843 * SG_IO wants current and deferred errors
845 int len
= 8 + cmd
->sense_buffer
[7];
847 if (len
> SCSI_SENSE_BUFFERSIZE
)
848 len
= SCSI_SENSE_BUFFERSIZE
;
849 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
850 req
->sense_len
= len
;
853 req
->data_len
= cmd
->resid
;
857 * Next deal with any sectors which we were able to correctly
860 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
862 req
->nr_sectors
, good_bytes
));
863 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
868 /* A number of bytes were successfully read. If there
869 * are leftovers and there is some kind of error
870 * (result != 0), retry the rest.
872 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
875 /* good_bytes = 0, or (inclusive) there were leftovers and
876 * result = 0, so scsi_end_request couldn't retry.
878 if (sense_valid
&& !sense_deferred
) {
879 switch (sshdr
.sense_key
) {
881 if (cmd
->device
->removable
) {
882 /* Detected disc change. Set a bit
883 * and quietly refuse further access.
885 cmd
->device
->changed
= 1;
886 scsi_end_request(cmd
, 0, this_count
, 1);
889 /* Must have been a power glitch, or a
890 * bus reset. Could not have been a
891 * media change, so we just retry the
892 * request and see what happens.
894 scsi_requeue_command(q
, cmd
);
898 case ILLEGAL_REQUEST
:
899 /* If we had an ILLEGAL REQUEST returned, then
900 * we may have performed an unsupported
901 * command. The only thing this should be
902 * would be a ten byte read where only a six
903 * byte read was supported. Also, on a system
904 * where READ CAPACITY failed, we may have
905 * read past the end of the disk.
907 if ((cmd
->device
->use_10_for_rw
&&
908 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
909 (cmd
->cmnd
[0] == READ_10
||
910 cmd
->cmnd
[0] == WRITE_10
)) {
911 cmd
->device
->use_10_for_rw
= 0;
912 /* This will cause a retry with a
915 scsi_requeue_command(q
, cmd
);
918 scsi_end_request(cmd
, 0, this_count
, 1);
923 /* If the device is in the process of becoming
924 * ready, or has a temporary blockage, retry.
926 if (sshdr
.asc
== 0x04) {
927 switch (sshdr
.ascq
) {
928 case 0x01: /* becoming ready */
929 case 0x04: /* format in progress */
930 case 0x05: /* rebuild in progress */
931 case 0x06: /* recalculation in progress */
932 case 0x07: /* operation in progress */
933 case 0x08: /* Long write in progress */
934 case 0x09: /* self test in progress */
935 scsi_requeue_command(q
, cmd
);
941 if (!(req
->cmd_flags
& REQ_QUIET
)) {
942 scmd_printk(KERN_INFO
, cmd
,
943 "Device not ready: ");
944 scsi_print_sense_hdr("", &sshdr
);
946 scsi_end_request(cmd
, 0, this_count
, 1);
948 case VOLUME_OVERFLOW
:
949 if (!(req
->cmd_flags
& REQ_QUIET
)) {
950 scmd_printk(KERN_INFO
, cmd
,
951 "Volume overflow, CDB: ");
952 __scsi_print_command(cmd
->cmnd
);
953 scsi_print_sense("", cmd
);
955 /* See SSC3rXX or current. */
956 scsi_end_request(cmd
, 0, this_count
, 1);
962 if (host_byte(result
) == DID_RESET
) {
963 /* Third party bus reset or reset for error recovery
964 * reasons. Just retry the request and see what
967 scsi_requeue_command(q
, cmd
);
971 if (!(req
->cmd_flags
& REQ_QUIET
)) {
972 scmd_printk(KERN_INFO
, cmd
,
973 "SCSI error: return code = 0x%08x\n",
975 if (driver_byte(result
) & DRIVER_SENSE
)
976 scsi_print_sense("", cmd
);
979 scsi_end_request(cmd
, 0, this_count
, !result
);
981 EXPORT_SYMBOL(scsi_io_completion
);
984 * Function: scsi_init_io()
986 * Purpose: SCSI I/O initialize function.
988 * Arguments: cmd - Command descriptor we wish to initialize
990 * Returns: 0 on success
991 * BLKPREP_DEFER if the failure is retryable
992 * BLKPREP_KILL if the failure is fatal
994 static int scsi_init_io(struct scsi_cmnd
*cmd
)
996 struct request
*req
= cmd
->request
;
997 struct scatterlist
*sgpnt
;
1001 * We used to not use scatter-gather for single segment request,
1002 * but now we do (it makes highmem I/O easier to support without
1005 cmd
->use_sg
= req
->nr_phys_segments
;
1008 * If sg table allocation fails, requeue request later.
1010 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
1011 if (unlikely(!sgpnt
)) {
1012 scsi_unprep_request(req
);
1013 return BLKPREP_DEFER
;
1017 cmd
->request_buffer
= (char *) sgpnt
;
1018 if (blk_pc_request(req
))
1019 cmd
->request_bufflen
= req
->data_len
;
1021 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1024 * Next, walk the list, and fill in the addresses and sizes of
1027 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1028 if (likely(count
<= cmd
->use_sg
)) {
1029 cmd
->use_sg
= count
;
1033 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1034 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1035 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1036 req
->current_nr_sectors
);
1038 /* release the command and kill it */
1039 scsi_release_buffers(cmd
);
1040 scsi_put_command(cmd
);
1041 return BLKPREP_KILL
;
1044 static int scsi_issue_flush_fn(request_queue_t
*q
, struct gendisk
*disk
,
1045 sector_t
*error_sector
)
1047 struct scsi_device
*sdev
= q
->queuedata
;
1048 struct scsi_driver
*drv
;
1050 if (sdev
->sdev_state
!= SDEV_RUNNING
)
1053 drv
= *(struct scsi_driver
**) disk
->private_data
;
1054 if (drv
->issue_flush
)
1055 return drv
->issue_flush(&sdev
->sdev_gendev
, error_sector
);
1060 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1061 struct request
*req
)
1063 struct scsi_cmnd
*cmd
;
1065 if (!req
->special
) {
1066 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1074 /* pull a tag out of the request if we have one */
1075 cmd
->tag
= req
->tag
;
1081 static void scsi_blk_pc_done(struct scsi_cmnd
*cmd
)
1083 BUG_ON(!blk_pc_request(cmd
->request
));
1085 * This will complete the whole command with uptodate=1 so
1086 * as far as the block layer is concerned the command completed
1087 * successfully. Since this is a REQ_BLOCK_PC command the
1088 * caller should check the request's errors value
1090 scsi_io_completion(cmd
, cmd
->request_bufflen
);
1093 static int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1095 struct scsi_cmnd
*cmd
;
1097 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1099 return BLKPREP_DEFER
;
1102 * BLOCK_PC requests may transfer data, in which case they must
1103 * a bio attached to them. Or they might contain a SCSI command
1104 * that does not transfer data, in which case they may optionally
1105 * submit a request without an attached bio.
1110 BUG_ON(!req
->nr_phys_segments
);
1112 ret
= scsi_init_io(cmd
);
1116 BUG_ON(req
->data_len
);
1119 cmd
->request_bufflen
= 0;
1120 cmd
->request_buffer
= NULL
;
1125 BUILD_BUG_ON(sizeof(req
->cmd
) > sizeof(cmd
->cmnd
));
1126 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1127 cmd
->cmd_len
= req
->cmd_len
;
1129 cmd
->sc_data_direction
= DMA_NONE
;
1130 else if (rq_data_dir(req
) == WRITE
)
1131 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1133 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1135 cmd
->transfersize
= req
->data_len
;
1136 cmd
->allowed
= req
->retries
;
1137 cmd
->timeout_per_command
= req
->timeout
;
1138 cmd
->done
= scsi_blk_pc_done
;
1143 * Setup a REQ_TYPE_FS command. These are simple read/write request
1144 * from filesystems that still need to be translated to SCSI CDBs from
1147 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1149 struct scsi_cmnd
*cmd
;
1150 struct scsi_driver
*drv
;
1154 * Filesystem requests must transfer data.
1156 BUG_ON(!req
->nr_phys_segments
);
1158 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1160 return BLKPREP_DEFER
;
1162 ret
= scsi_init_io(cmd
);
1167 * Initialize the actual SCSI command for this request.
1169 drv
= *(struct scsi_driver
**)req
->rq_disk
->private_data
;
1170 if (unlikely(!drv
->init_command(cmd
))) {
1171 scsi_release_buffers(cmd
);
1172 scsi_put_command(cmd
);
1173 return BLKPREP_KILL
;
1179 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1181 struct scsi_device
*sdev
= q
->queuedata
;
1182 int ret
= BLKPREP_OK
;
1185 * If the device is not in running state we will reject some
1188 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1189 switch (sdev
->sdev_state
) {
1192 * If the device is offline we refuse to process any
1193 * commands. The device must be brought online
1194 * before trying any recovery commands.
1196 sdev_printk(KERN_ERR
, sdev
,
1197 "rejecting I/O to offline device\n");
1202 * If the device is fully deleted, we refuse to
1203 * process any commands as well.
1205 sdev_printk(KERN_ERR
, sdev
,
1206 "rejecting I/O to dead device\n");
1212 * If the devices is blocked we defer normal commands.
1214 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1215 ret
= BLKPREP_DEFER
;
1219 * For any other not fully online state we only allow
1220 * special commands. In particular any user initiated
1221 * command is not allowed.
1223 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1228 if (ret
!= BLKPREP_OK
)
1232 switch (req
->cmd_type
) {
1233 case REQ_TYPE_BLOCK_PC
:
1234 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1237 ret
= scsi_setup_fs_cmnd(sdev
, req
);
1241 * All other command types are not supported.
1243 * Note that these days the SCSI subsystem does not use
1244 * REQ_TYPE_SPECIAL requests anymore. These are only used
1245 * (directly or via blk_insert_request) by non-SCSI drivers.
1247 blk_dump_rq_flags(req
, "SCSI bad req");
1255 req
->errors
= DID_NO_CONNECT
<< 16;
1259 * If we defer, the elv_next_request() returns NULL, but the
1260 * queue must be restarted, so we plug here if no returning
1261 * command will automatically do that.
1263 if (sdev
->device_busy
== 0)
1267 req
->cmd_flags
|= REQ_DONTPREP
;
1274 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1277 * Called with the queue_lock held.
1279 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1280 struct scsi_device
*sdev
)
1282 if (sdev
->device_busy
>= sdev
->queue_depth
)
1284 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1286 * unblock after device_blocked iterates to zero
1288 if (--sdev
->device_blocked
== 0) {
1290 sdev_printk(KERN_INFO
, sdev
,
1291 "unblocking device at zero depth\n"));
1297 if (sdev
->device_blocked
)
1304 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1305 * return 0. We must end up running the queue again whenever 0 is
1306 * returned, else IO can hang.
1308 * Called with host_lock held.
1310 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1311 struct Scsi_Host
*shost
,
1312 struct scsi_device
*sdev
)
1314 if (scsi_host_in_recovery(shost
))
1316 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1318 * unblock after host_blocked iterates to zero
1320 if (--shost
->host_blocked
== 0) {
1322 printk("scsi%d unblocking host at zero depth\n",
1329 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1330 shost
->host_blocked
|| shost
->host_self_blocked
) {
1331 if (list_empty(&sdev
->starved_entry
))
1332 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1336 /* We're OK to process the command, so we can't be starved */
1337 if (!list_empty(&sdev
->starved_entry
))
1338 list_del_init(&sdev
->starved_entry
);
1344 * Kill a request for a dead device
1346 static void scsi_kill_request(struct request
*req
, request_queue_t
*q
)
1348 struct scsi_cmnd
*cmd
= req
->special
;
1349 struct scsi_device
*sdev
= cmd
->device
;
1350 struct Scsi_Host
*shost
= sdev
->host
;
1352 blkdev_dequeue_request(req
);
1354 if (unlikely(cmd
== NULL
)) {
1355 printk(KERN_CRIT
"impossible request in %s.\n",
1360 scsi_init_cmd_errh(cmd
);
1361 cmd
->result
= DID_NO_CONNECT
<< 16;
1362 atomic_inc(&cmd
->device
->iorequest_cnt
);
1365 * SCSI request completion path will do scsi_device_unbusy(),
1366 * bump busy counts. To bump the counters, we need to dance
1367 * with the locks as normal issue path does.
1369 sdev
->device_busy
++;
1370 spin_unlock(sdev
->request_queue
->queue_lock
);
1371 spin_lock(shost
->host_lock
);
1373 spin_unlock(shost
->host_lock
);
1374 spin_lock(sdev
->request_queue
->queue_lock
);
1379 static void scsi_softirq_done(struct request
*rq
)
1381 struct scsi_cmnd
*cmd
= rq
->completion_data
;
1382 unsigned long wait_for
= (cmd
->allowed
+ 1) * cmd
->timeout_per_command
;
1385 INIT_LIST_HEAD(&cmd
->eh_entry
);
1387 disposition
= scsi_decide_disposition(cmd
);
1388 if (disposition
!= SUCCESS
&&
1389 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1390 sdev_printk(KERN_ERR
, cmd
->device
,
1391 "timing out command, waited %lus\n",
1393 disposition
= SUCCESS
;
1396 scsi_log_completion(cmd
, disposition
);
1398 switch (disposition
) {
1400 scsi_finish_command(cmd
);
1403 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1405 case ADD_TO_MLQUEUE
:
1406 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1409 if (!scsi_eh_scmd_add(cmd
, 0))
1410 scsi_finish_command(cmd
);
1415 * Function: scsi_request_fn()
1417 * Purpose: Main strategy routine for SCSI.
1419 * Arguments: q - Pointer to actual queue.
1423 * Lock status: IO request lock assumed to be held when called.
1425 static void scsi_request_fn(struct request_queue
*q
)
1427 struct scsi_device
*sdev
= q
->queuedata
;
1428 struct Scsi_Host
*shost
;
1429 struct scsi_cmnd
*cmd
;
1430 struct request
*req
;
1433 printk("scsi: killing requests for dead queue\n");
1434 while ((req
= elv_next_request(q
)) != NULL
)
1435 scsi_kill_request(req
, q
);
1439 if(!get_device(&sdev
->sdev_gendev
))
1440 /* We must be tearing the block queue down already */
1444 * To start with, we keep looping until the queue is empty, or until
1445 * the host is no longer able to accept any more requests.
1448 while (!blk_queue_plugged(q
)) {
1451 * get next queueable request. We do this early to make sure
1452 * that the request is fully prepared even if we cannot
1455 req
= elv_next_request(q
);
1456 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1459 if (unlikely(!scsi_device_online(sdev
))) {
1460 sdev_printk(KERN_ERR
, sdev
,
1461 "rejecting I/O to offline device\n");
1462 scsi_kill_request(req
, q
);
1468 * Remove the request from the request list.
1470 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1471 blkdev_dequeue_request(req
);
1472 sdev
->device_busy
++;
1474 spin_unlock(q
->queue_lock
);
1476 if (unlikely(cmd
== NULL
)) {
1477 printk(KERN_CRIT
"impossible request in %s.\n"
1478 "please mail a stack trace to "
1479 "linux-scsi@vger.kernel.org\n",
1481 blk_dump_rq_flags(req
, "foo");
1484 spin_lock(shost
->host_lock
);
1486 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1488 if (sdev
->single_lun
) {
1489 if (scsi_target(sdev
)->starget_sdev_user
&&
1490 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1492 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1497 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1498 * take the lock again.
1500 spin_unlock_irq(shost
->host_lock
);
1503 * Finally, initialize any error handling parameters, and set up
1504 * the timers for timeouts.
1506 scsi_init_cmd_errh(cmd
);
1509 * Dispatch the command to the low-level driver.
1511 rtn
= scsi_dispatch_cmd(cmd
);
1512 spin_lock_irq(q
->queue_lock
);
1514 /* we're refusing the command; because of
1515 * the way locks get dropped, we need to
1516 * check here if plugging is required */
1517 if(sdev
->device_busy
== 0)
1527 spin_unlock_irq(shost
->host_lock
);
1530 * lock q, handle tag, requeue req, and decrement device_busy. We
1531 * must return with queue_lock held.
1533 * Decrementing device_busy without checking it is OK, as all such
1534 * cases (host limits or settings) should run the queue at some
1537 spin_lock_irq(q
->queue_lock
);
1538 blk_requeue_request(q
, req
);
1539 sdev
->device_busy
--;
1540 if(sdev
->device_busy
== 0)
1543 /* must be careful here...if we trigger the ->remove() function
1544 * we cannot be holding the q lock */
1545 spin_unlock_irq(q
->queue_lock
);
1546 put_device(&sdev
->sdev_gendev
);
1547 spin_lock_irq(q
->queue_lock
);
1550 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1552 struct device
*host_dev
;
1553 u64 bounce_limit
= 0xffffffff;
1555 if (shost
->unchecked_isa_dma
)
1556 return BLK_BOUNCE_ISA
;
1558 * Platforms with virtual-DMA translation
1559 * hardware have no practical limit.
1561 if (!PCI_DMA_BUS_IS_PHYS
)
1562 return BLK_BOUNCE_ANY
;
1564 host_dev
= scsi_get_device(shost
);
1565 if (host_dev
&& host_dev
->dma_mask
)
1566 bounce_limit
= *host_dev
->dma_mask
;
1568 return bounce_limit
;
1570 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1572 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1573 request_fn_proc
*request_fn
)
1575 struct request_queue
*q
;
1577 q
= blk_init_queue(request_fn
, NULL
);
1581 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1582 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1583 blk_queue_max_sectors(q
, shost
->max_sectors
);
1584 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1585 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1587 if (!shost
->use_clustering
)
1588 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1591 EXPORT_SYMBOL(__scsi_alloc_queue
);
1593 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1595 struct request_queue
*q
;
1597 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1601 blk_queue_prep_rq(q
, scsi_prep_fn
);
1602 blk_queue_issue_flush_fn(q
, scsi_issue_flush_fn
);
1603 blk_queue_softirq_done(q
, scsi_softirq_done
);
1607 void scsi_free_queue(struct request_queue
*q
)
1609 blk_cleanup_queue(q
);
1613 * Function: scsi_block_requests()
1615 * Purpose: Utility function used by low-level drivers to prevent further
1616 * commands from being queued to the device.
1618 * Arguments: shost - Host in question
1622 * Lock status: No locks are assumed held.
1624 * Notes: There is no timer nor any other means by which the requests
1625 * get unblocked other than the low-level driver calling
1626 * scsi_unblock_requests().
1628 void scsi_block_requests(struct Scsi_Host
*shost
)
1630 shost
->host_self_blocked
= 1;
1632 EXPORT_SYMBOL(scsi_block_requests
);
1635 * Function: scsi_unblock_requests()
1637 * Purpose: Utility function used by low-level drivers to allow further
1638 * commands from being queued to the device.
1640 * Arguments: shost - Host in question
1644 * Lock status: No locks are assumed held.
1646 * Notes: There is no timer nor any other means by which the requests
1647 * get unblocked other than the low-level driver calling
1648 * scsi_unblock_requests().
1650 * This is done as an API function so that changes to the
1651 * internals of the scsi mid-layer won't require wholesale
1652 * changes to drivers that use this feature.
1654 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1656 shost
->host_self_blocked
= 0;
1657 scsi_run_host_queues(shost
);
1659 EXPORT_SYMBOL(scsi_unblock_requests
);
1661 int __init
scsi_init_queue(void)
1665 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1666 sizeof(struct scsi_io_context
),
1668 if (!scsi_io_context_cache
) {
1669 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1673 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1674 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1675 int size
= sgp
->size
* sizeof(struct scatterlist
);
1677 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1678 SLAB_HWCACHE_ALIGN
, NULL
, NULL
);
1680 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1684 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1687 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1695 void scsi_exit_queue(void)
1699 kmem_cache_destroy(scsi_io_context_cache
);
1701 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1702 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1703 mempool_destroy(sgp
->pool
);
1704 kmem_cache_destroy(sgp
->slab
);
1709 * scsi_mode_select - issue a mode select
1710 * @sdev: SCSI device to be queried
1711 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1712 * @sp: Save page bit (0 == don't save, 1 == save)
1713 * @modepage: mode page being requested
1714 * @buffer: request buffer (may not be smaller than eight bytes)
1715 * @len: length of request buffer.
1716 * @timeout: command timeout
1717 * @retries: number of retries before failing
1718 * @data: returns a structure abstracting the mode header data
1719 * @sense: place to put sense data (or NULL if no sense to be collected).
1720 * must be SCSI_SENSE_BUFFERSIZE big.
1722 * Returns zero if successful; negative error number or scsi
1727 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1728 unsigned char *buffer
, int len
, int timeout
, int retries
,
1729 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1731 unsigned char cmd
[10];
1732 unsigned char *real_buffer
;
1735 memset(cmd
, 0, sizeof(cmd
));
1736 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1738 if (sdev
->use_10_for_ms
) {
1741 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1744 memcpy(real_buffer
+ 8, buffer
, len
);
1748 real_buffer
[2] = data
->medium_type
;
1749 real_buffer
[3] = data
->device_specific
;
1750 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1752 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1753 real_buffer
[7] = data
->block_descriptor_length
;
1755 cmd
[0] = MODE_SELECT_10
;
1759 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1763 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1766 memcpy(real_buffer
+ 4, buffer
, len
);
1769 real_buffer
[1] = data
->medium_type
;
1770 real_buffer
[2] = data
->device_specific
;
1771 real_buffer
[3] = data
->block_descriptor_length
;
1774 cmd
[0] = MODE_SELECT
;
1778 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1779 sshdr
, timeout
, retries
);
1783 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1786 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1787 * six bytes if necessary.
1788 * @sdev: SCSI device to be queried
1789 * @dbd: set if mode sense will allow block descriptors to be returned
1790 * @modepage: mode page being requested
1791 * @buffer: request buffer (may not be smaller than eight bytes)
1792 * @len: length of request buffer.
1793 * @timeout: command timeout
1794 * @retries: number of retries before failing
1795 * @data: returns a structure abstracting the mode header data
1796 * @sense: place to put sense data (or NULL if no sense to be collected).
1797 * must be SCSI_SENSE_BUFFERSIZE big.
1799 * Returns zero if unsuccessful, or the header offset (either 4
1800 * or 8 depending on whether a six or ten byte command was
1801 * issued) if successful.
1804 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1805 unsigned char *buffer
, int len
, int timeout
, int retries
,
1806 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1808 unsigned char cmd
[12];
1812 struct scsi_sense_hdr my_sshdr
;
1814 memset(data
, 0, sizeof(*data
));
1815 memset(&cmd
[0], 0, 12);
1816 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1819 /* caller might not be interested in sense, but we need it */
1824 use_10_for_ms
= sdev
->use_10_for_ms
;
1826 if (use_10_for_ms
) {
1830 cmd
[0] = MODE_SENSE_10
;
1837 cmd
[0] = MODE_SENSE
;
1842 memset(buffer
, 0, len
);
1844 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1845 sshdr
, timeout
, retries
);
1847 /* This code looks awful: what it's doing is making sure an
1848 * ILLEGAL REQUEST sense return identifies the actual command
1849 * byte as the problem. MODE_SENSE commands can return
1850 * ILLEGAL REQUEST if the code page isn't supported */
1852 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1853 (driver_byte(result
) & DRIVER_SENSE
)) {
1854 if (scsi_sense_valid(sshdr
)) {
1855 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1856 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1858 * Invalid command operation code
1860 sdev
->use_10_for_ms
= 0;
1866 if(scsi_status_is_good(result
)) {
1867 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1868 (modepage
== 6 || modepage
== 8))) {
1869 /* Initio breakage? */
1872 data
->medium_type
= 0;
1873 data
->device_specific
= 0;
1875 data
->block_descriptor_length
= 0;
1876 } else if(use_10_for_ms
) {
1877 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1878 data
->medium_type
= buffer
[2];
1879 data
->device_specific
= buffer
[3];
1880 data
->longlba
= buffer
[4] & 0x01;
1881 data
->block_descriptor_length
= buffer
[6]*256
1884 data
->length
= buffer
[0] + 1;
1885 data
->medium_type
= buffer
[1];
1886 data
->device_specific
= buffer
[2];
1887 data
->block_descriptor_length
= buffer
[3];
1889 data
->header_length
= header_length
;
1894 EXPORT_SYMBOL(scsi_mode_sense
);
1897 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1900 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1902 struct scsi_sense_hdr sshdr
;
1905 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1908 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1910 if ((scsi_sense_valid(&sshdr
)) &&
1911 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1912 (sshdr
.sense_key
== NOT_READY
))) {
1919 EXPORT_SYMBOL(scsi_test_unit_ready
);
1922 * scsi_device_set_state - Take the given device through the device
1924 * @sdev: scsi device to change the state of.
1925 * @state: state to change to.
1927 * Returns zero if unsuccessful or an error if the requested
1928 * transition is illegal.
1931 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1933 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1935 if (state
== oldstate
)
1940 /* There are no legal states that come back to
1941 * created. This is the manually initialised start
2015 sdev
->sdev_state
= state
;
2019 SCSI_LOG_ERROR_RECOVERY(1,
2020 sdev_printk(KERN_ERR
, sdev
,
2021 "Illegal state transition %s->%s\n",
2022 scsi_device_state_name(oldstate
),
2023 scsi_device_state_name(state
))
2027 EXPORT_SYMBOL(scsi_device_set_state
);
2030 * scsi_device_quiesce - Block user issued commands.
2031 * @sdev: scsi device to quiesce.
2033 * This works by trying to transition to the SDEV_QUIESCE state
2034 * (which must be a legal transition). When the device is in this
2035 * state, only special requests will be accepted, all others will
2036 * be deferred. Since special requests may also be requeued requests,
2037 * a successful return doesn't guarantee the device will be
2038 * totally quiescent.
2040 * Must be called with user context, may sleep.
2042 * Returns zero if unsuccessful or an error if not.
2045 scsi_device_quiesce(struct scsi_device
*sdev
)
2047 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2051 scsi_run_queue(sdev
->request_queue
);
2052 while (sdev
->device_busy
) {
2053 msleep_interruptible(200);
2054 scsi_run_queue(sdev
->request_queue
);
2058 EXPORT_SYMBOL(scsi_device_quiesce
);
2061 * scsi_device_resume - Restart user issued commands to a quiesced device.
2062 * @sdev: scsi device to resume.
2064 * Moves the device from quiesced back to running and restarts the
2067 * Must be called with user context, may sleep.
2070 scsi_device_resume(struct scsi_device
*sdev
)
2072 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2074 scsi_run_queue(sdev
->request_queue
);
2076 EXPORT_SYMBOL(scsi_device_resume
);
2079 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2081 scsi_device_quiesce(sdev
);
2085 scsi_target_quiesce(struct scsi_target
*starget
)
2087 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2089 EXPORT_SYMBOL(scsi_target_quiesce
);
2092 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2094 scsi_device_resume(sdev
);
2098 scsi_target_resume(struct scsi_target
*starget
)
2100 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2102 EXPORT_SYMBOL(scsi_target_resume
);
2105 * scsi_internal_device_block - internal function to put a device
2106 * temporarily into the SDEV_BLOCK state
2107 * @sdev: device to block
2109 * Block request made by scsi lld's to temporarily stop all
2110 * scsi commands on the specified device. Called from interrupt
2111 * or normal process context.
2113 * Returns zero if successful or error if not
2116 * This routine transitions the device to the SDEV_BLOCK state
2117 * (which must be a legal transition). When the device is in this
2118 * state, all commands are deferred until the scsi lld reenables
2119 * the device with scsi_device_unblock or device_block_tmo fires.
2120 * This routine assumes the host_lock is held on entry.
2123 scsi_internal_device_block(struct scsi_device
*sdev
)
2125 request_queue_t
*q
= sdev
->request_queue
;
2126 unsigned long flags
;
2129 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2134 * The device has transitioned to SDEV_BLOCK. Stop the
2135 * block layer from calling the midlayer with this device's
2138 spin_lock_irqsave(q
->queue_lock
, flags
);
2140 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2144 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2147 * scsi_internal_device_unblock - resume a device after a block request
2148 * @sdev: device to resume
2150 * Called by scsi lld's or the midlayer to restart the device queue
2151 * for the previously suspended scsi device. Called from interrupt or
2152 * normal process context.
2154 * Returns zero if successful or error if not.
2157 * This routine transitions the device to the SDEV_RUNNING state
2158 * (which must be a legal transition) allowing the midlayer to
2159 * goose the queue for this device. This routine assumes the
2160 * host_lock is held upon entry.
2163 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2165 request_queue_t
*q
= sdev
->request_queue
;
2167 unsigned long flags
;
2170 * Try to transition the scsi device to SDEV_RUNNING
2171 * and goose the device queue if successful.
2173 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2177 spin_lock_irqsave(q
->queue_lock
, flags
);
2179 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2183 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2186 device_block(struct scsi_device
*sdev
, void *data
)
2188 scsi_internal_device_block(sdev
);
2192 target_block(struct device
*dev
, void *data
)
2194 if (scsi_is_target_device(dev
))
2195 starget_for_each_device(to_scsi_target(dev
), NULL
,
2201 scsi_target_block(struct device
*dev
)
2203 if (scsi_is_target_device(dev
))
2204 starget_for_each_device(to_scsi_target(dev
), NULL
,
2207 device_for_each_child(dev
, NULL
, target_block
);
2209 EXPORT_SYMBOL_GPL(scsi_target_block
);
2212 device_unblock(struct scsi_device
*sdev
, void *data
)
2214 scsi_internal_device_unblock(sdev
);
2218 target_unblock(struct device
*dev
, void *data
)
2220 if (scsi_is_target_device(dev
))
2221 starget_for_each_device(to_scsi_target(dev
), NULL
,
2227 scsi_target_unblock(struct device
*dev
)
2229 if (scsi_is_target_device(dev
))
2230 starget_for_each_device(to_scsi_target(dev
), NULL
,
2233 device_for_each_child(dev
, NULL
, target_unblock
);
2235 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2238 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2239 * @sg: scatter-gather list
2240 * @sg_count: number of segments in sg
2241 * @offset: offset in bytes into sg, on return offset into the mapped area
2242 * @len: bytes to map, on return number of bytes mapped
2244 * Returns virtual address of the start of the mapped page
2246 void *scsi_kmap_atomic_sg(struct scatterlist
*sg
, int sg_count
,
2247 size_t *offset
, size_t *len
)
2250 size_t sg_len
= 0, len_complete
= 0;
2253 for (i
= 0; i
< sg_count
; i
++) {
2254 len_complete
= sg_len
; /* Complete sg-entries */
2255 sg_len
+= sg
[i
].length
;
2256 if (sg_len
> *offset
)
2260 if (unlikely(i
== sg_count
)) {
2261 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2263 __FUNCTION__
, sg_len
, *offset
, sg_count
);
2268 /* Offset starting from the beginning of first page in this sg-entry */
2269 *offset
= *offset
- len_complete
+ sg
[i
].offset
;
2271 /* Assumption: contiguous pages can be accessed as "page + i" */
2272 page
= nth_page(sg
[i
].page
, (*offset
>> PAGE_SHIFT
));
2273 *offset
&= ~PAGE_MASK
;
2275 /* Bytes in this sg-entry from *offset to the end of the page */
2276 sg_len
= PAGE_SIZE
- *offset
;
2280 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2282 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2285 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2286 * mapped with scsi_kmap_atomic_sg
2287 * @virt: virtual address to be unmapped
2289 void scsi_kunmap_atomic_sg(void *virt
)
2291 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2293 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);