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>
20 #include <linux/scatterlist.h>
22 #include <scsi/scsi.h>
23 #include <scsi/scsi_cmnd.h>
24 #include <scsi/scsi_dbg.h>
25 #include <scsi/scsi_device.h>
26 #include <scsi/scsi_driver.h>
27 #include <scsi/scsi_eh.h>
28 #include <scsi/scsi_host.h>
30 #include "scsi_priv.h"
31 #include "scsi_logging.h"
34 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
35 #define SG_MEMPOOL_SIZE 2
37 struct scsi_host_sg_pool {
40 struct kmem_cache *slab;
44 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
45 #error SCSI_MAX_PHYS_SEGMENTS is too small
48 #define SP(x) { x, "sgpool-" #x }
49 static struct scsi_host_sg_pool scsi_sg_pools[] = {
53 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
55 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
57 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
59 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
60 #error SCSI_MAX_PHYS_SEGMENTS is too large
68 static void scsi_run_queue(struct request_queue *q);
71 * Function: scsi_unprep_request()
73 * Purpose: Remove all preparation done for a request, including its
74 * associated scsi_cmnd, so that it can be requeued.
76 * Arguments: req - request to unprepare
78 * Lock status: Assumed that no locks are held upon entry.
82 static void scsi_unprep_request(struct request *req)
84 struct scsi_cmnd *cmd = req->special;
86 req->cmd_flags &= ~REQ_DONTPREP;
89 scsi_put_command(cmd);
93 * Function: scsi_queue_insert()
95 * Purpose: Insert a command in the midlevel queue.
97 * Arguments: cmd - command that we are adding to queue.
98 * reason - why we are inserting command to queue.
100 * Lock status: Assumed that lock is not held upon entry.
104 * Notes: We do this for one of two cases. Either the host is busy
105 * and it cannot accept any more commands for the time being,
106 * or the device returned QUEUE_FULL and can accept no more
108 * Notes: This could be called either from an interrupt context or a
109 * normal process context.
111 int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
113 struct Scsi_Host *host = cmd->device->host;
114 struct scsi_device *device = cmd->device;
115 struct request_queue *q = device->request_queue;
119 printk("Inserting command %p into mlqueue\n", cmd));
122 * Set the appropriate busy bit for the device/host.
124 * If the host/device isn't busy, assume that something actually
125 * completed, and that we should be able to queue a command now.
127 * Note that the prior mid-layer assumption that any host could
128 * always queue at least one command is now broken. The mid-layer
129 * will implement a user specifiable stall (see
130 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
131 * if a command is requeued with no other commands outstanding
132 * either for the device or for the host.
134 if (reason == SCSI_MLQUEUE_HOST_BUSY)
135 host->host_blocked = host->max_host_blocked;
136 else if (reason == SCSI_MLQUEUE_DEVICE_BUSY)
137 device->device_blocked = device->max_device_blocked;
140 * Decrement the counters, since these commands are no longer
141 * active on the host/device.
143 scsi_device_unbusy(device);
146 * Requeue this command. It will go before all other commands
147 * that are already in the queue.
149 * NOTE: there is magic here about the way the queue is plugged if
150 * we have no outstanding commands.
152 * Although we *don't* plug the queue, we call the request
153 * function. The SCSI request function detects the blocked condition
154 * and plugs the queue appropriately.
156 spin_lock_irqsave(q->queue_lock, flags);
157 blk_requeue_request(q, cmd->request);
158 spin_unlock_irqrestore(q->queue_lock, flags);
166 * scsi_execute - insert request and wait for the result
169 * @data_direction: data direction
170 * @buffer: data buffer
171 * @bufflen: len of buffer
172 * @sense: optional sense buffer
173 * @timeout: request timeout in seconds
174 * @retries: number of times to retry request
175 * @flags: or into request flags;
177 * returns the req->errors value which is the scsi_cmnd result
180 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
181 int data_direction, void *buffer, unsigned bufflen,
182 unsigned char *sense, int timeout, int retries, int flags)
185 int write = (data_direction == DMA_TO_DEVICE);
186 int ret = DRIVER_ERROR << 24;
188 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
190 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
191 buffer, bufflen, __GFP_WAIT))
194 req->cmd_len = COMMAND_SIZE(cmd[0]);
195 memcpy(req->cmd, cmd, req->cmd_len);
198 req->retries = retries;
199 req->timeout = timeout;
200 req->cmd_type = REQ_TYPE_BLOCK_PC;
201 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
204 * head injection *required* here otherwise quiesce won't work
206 blk_execute_rq(req->q, NULL, req, 1);
210 blk_put_request(req);
214 EXPORT_SYMBOL(scsi_execute);
217 int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
218 int data_direction, void *buffer, unsigned bufflen,
219 struct scsi_sense_hdr *sshdr, int timeout, int retries)
225 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
227 return DRIVER_ERROR << 24;
229 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
230 sense, timeout, retries, 0);
232 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
237 EXPORT_SYMBOL(scsi_execute_req);
239 struct scsi_io_context {
241 void (*done)(void *data, char *sense, int result, int resid);
242 char sense[SCSI_SENSE_BUFFERSIZE];
245 static struct kmem_cache *scsi_io_context_cache;
247 static void scsi_end_async(struct request *req, int uptodate)
249 struct scsi_io_context *sioc = req->end_io_data;
252 sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
254 kmem_cache_free(scsi_io_context_cache, sioc);
255 __blk_put_request(req->q, req);
258 static int scsi_merge_bio(struct request *rq, struct bio *bio)
260 struct request_queue *q = rq->q;
262 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
263 if (rq_data_dir(rq) == WRITE)
264 bio->bi_rw |= (1 << BIO_RW);
265 blk_queue_bounce(q, &bio);
267 return blk_rq_append_bio(q, rq, bio);
270 static void scsi_bi_endio(struct bio *bio, int error)
276 * scsi_req_map_sg - map a scatterlist into a request
277 * @rq: request to fill
279 * @nsegs: number of elements
280 * @bufflen: len of buffer
281 * @gfp: memory allocation flags
283 * scsi_req_map_sg maps a scatterlist into a request so that the
284 * request can be sent to the block layer. We do not trust the scatterlist
285 * sent to use, as some ULDs use that struct to only organize the pages.
287 static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
288 int nsegs, unsigned bufflen, gfp_t gfp)
290 struct request_queue *q = rq->q;
291 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
292 unsigned int data_len = bufflen, len, bytes, off;
293 struct scatterlist *sg;
295 struct bio *bio = NULL;
296 int i, err, nr_vecs = 0;
298 for_each_sg(sgl, sg, nsegs, i) {
304 while (len > 0 && data_len > 0) {
306 * sg sends a scatterlist that is larger than
307 * the data_len it wants transferred for certain
310 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
311 bytes = min(bytes, data_len);
314 nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
317 bio = bio_alloc(gfp, nr_vecs);
322 bio->bi_end_io = scsi_bi_endio;
325 if (bio_add_pc_page(q, bio, page, bytes, off) !=
332 if (bio->bi_vcnt >= nr_vecs) {
333 err = scsi_merge_bio(rq, bio);
348 rq->buffer = rq->data = NULL;
349 rq->data_len = bufflen;
353 while ((bio = rq->bio) != NULL) {
354 rq->bio = bio->bi_next;
356 * call endio instead of bio_put incase it was bounced
365 * scsi_execute_async - insert request
368 * @cmd_len: length of scsi cdb
369 * @data_direction: data direction
370 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
371 * @bufflen: len of buffer
372 * @use_sg: if buffer is a scatterlist this is the number of elements
373 * @timeout: request timeout in seconds
374 * @retries: number of times to retry request
375 * @flags: or into request flags
377 int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
378 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
379 int use_sg, int timeout, int retries, void *privdata,
380 void (*done)(void *, char *, int, int), gfp_t gfp)
383 struct scsi_io_context *sioc;
385 int write = (data_direction == DMA_TO_DEVICE);
387 sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
389 return DRIVER_ERROR << 24;
391 req = blk_get_request(sdev->request_queue, write, gfp);
394 req->cmd_type = REQ_TYPE_BLOCK_PC;
395 req->cmd_flags |= REQ_QUIET;
398 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
400 err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
405 req->cmd_len = cmd_len;
406 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
407 memcpy(req->cmd, cmd, req->cmd_len);
408 req->sense = sioc->sense;
410 req->timeout = timeout;
411 req->retries = retries;
412 req->end_io_data = sioc;
414 sioc->data = privdata;
417 blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
421 blk_put_request(req);
423 kmem_cache_free(scsi_io_context_cache, sioc);
424 return DRIVER_ERROR << 24;
426 EXPORT_SYMBOL_GPL(scsi_execute_async);
429 * Function: scsi_init_cmd_errh()
431 * Purpose: Initialize cmd fields related to error handling.
433 * Arguments: cmd - command that is ready to be queued.
435 * Notes: This function has the job of initializing a number of
436 * fields related to error handling. Typically this will
437 * be called once for each command, as required.
439 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
441 cmd->serial_number = 0;
443 memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer);
444 if (cmd->cmd_len == 0)
445 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
448 void scsi_device_unbusy(struct scsi_device *sdev)
450 struct Scsi_Host *shost = sdev->host;
453 spin_lock_irqsave(shost->host_lock, flags);
455 if (unlikely(scsi_host_in_recovery(shost) &&
456 (shost->host_failed || shost->host_eh_scheduled)))
457 scsi_eh_wakeup(shost);
458 spin_unlock(shost->host_lock);
459 spin_lock(sdev->request_queue->queue_lock);
461 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
465 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
466 * and call blk_run_queue for all the scsi_devices on the target -
467 * including current_sdev first.
469 * Called with *no* scsi locks held.
471 static void scsi_single_lun_run(struct scsi_device *current_sdev)
473 struct Scsi_Host *shost = current_sdev->host;
474 struct scsi_device *sdev, *tmp;
475 struct scsi_target *starget = scsi_target(current_sdev);
478 spin_lock_irqsave(shost->host_lock, flags);
479 starget->starget_sdev_user = NULL;
480 spin_unlock_irqrestore(shost->host_lock, flags);
483 * Call blk_run_queue for all LUNs on the target, starting with
484 * current_sdev. We race with others (to set starget_sdev_user),
485 * but in most cases, we will be first. Ideally, each LU on the
486 * target would get some limited time or requests on the target.
488 blk_run_queue(current_sdev->request_queue);
490 spin_lock_irqsave(shost->host_lock, flags);
491 if (starget->starget_sdev_user)
493 list_for_each_entry_safe(sdev, tmp, &starget->devices,
494 same_target_siblings) {
495 if (sdev == current_sdev)
497 if (scsi_device_get(sdev))
500 spin_unlock_irqrestore(shost->host_lock, flags);
501 blk_run_queue(sdev->request_queue);
502 spin_lock_irqsave(shost->host_lock, flags);
504 scsi_device_put(sdev);
507 spin_unlock_irqrestore(shost->host_lock, flags);
511 * Function: scsi_run_queue()
513 * Purpose: Select a proper request queue to serve next
515 * Arguments: q - last request's queue
519 * Notes: The previous command was completely finished, start
520 * a new one if possible.
522 static void scsi_run_queue(struct request_queue *q)
524 struct scsi_device *sdev = q->queuedata;
525 struct Scsi_Host *shost = sdev->host;
528 if (sdev->single_lun)
529 scsi_single_lun_run(sdev);
531 spin_lock_irqsave(shost->host_lock, flags);
532 while (!list_empty(&shost->starved_list) &&
533 !shost->host_blocked && !shost->host_self_blocked &&
534 !((shost->can_queue > 0) &&
535 (shost->host_busy >= shost->can_queue))) {
537 * As long as shost is accepting commands and we have
538 * starved queues, call blk_run_queue. scsi_request_fn
539 * drops the queue_lock and can add us back to the
542 * host_lock protects the starved_list and starved_entry.
543 * scsi_request_fn must get the host_lock before checking
544 * or modifying starved_list or starved_entry.
546 sdev = list_entry(shost->starved_list.next,
547 struct scsi_device, starved_entry);
548 list_del_init(&sdev->starved_entry);
549 spin_unlock_irqrestore(shost->host_lock, flags);
552 if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) &&
553 !test_and_set_bit(QUEUE_FLAG_REENTER,
554 &sdev->request_queue->queue_flags)) {
555 blk_run_queue(sdev->request_queue);
556 clear_bit(QUEUE_FLAG_REENTER,
557 &sdev->request_queue->queue_flags);
559 blk_run_queue(sdev->request_queue);
561 spin_lock_irqsave(shost->host_lock, flags);
562 if (unlikely(!list_empty(&sdev->starved_entry)))
564 * sdev lost a race, and was put back on the
565 * starved list. This is unlikely but without this
566 * in theory we could loop forever.
570 spin_unlock_irqrestore(shost->host_lock, flags);
576 * Function: scsi_requeue_command()
578 * Purpose: Handle post-processing of completed commands.
580 * Arguments: q - queue to operate on
581 * cmd - command that may need to be requeued.
585 * Notes: After command completion, there may be blocks left
586 * over which weren't finished by the previous command
587 * this can be for a number of reasons - the main one is
588 * I/O errors in the middle of the request, in which case
589 * we need to request the blocks that come after the bad
591 * Notes: Upon return, cmd is a stale pointer.
593 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
595 struct request *req = cmd->request;
598 scsi_unprep_request(req);
599 spin_lock_irqsave(q->queue_lock, flags);
600 blk_requeue_request(q, req);
601 spin_unlock_irqrestore(q->queue_lock, flags);
606 void scsi_next_command(struct scsi_cmnd *cmd)
608 struct scsi_device *sdev = cmd->device;
609 struct request_queue *q = sdev->request_queue;
611 /* need to hold a reference on the device before we let go of the cmd */
612 get_device(&sdev->sdev_gendev);
614 scsi_put_command(cmd);
617 /* ok to remove device now */
618 put_device(&sdev->sdev_gendev);
621 void scsi_run_host_queues(struct Scsi_Host *shost)
623 struct scsi_device *sdev;
625 shost_for_each_device(sdev, shost)
626 scsi_run_queue(sdev->request_queue);
630 * Function: scsi_end_request()
632 * Purpose: Post-processing of completed commands (usually invoked at end
633 * of upper level post-processing and scsi_io_completion).
635 * Arguments: cmd - command that is complete.
636 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
637 * bytes - number of bytes of completed I/O
638 * requeue - indicates whether we should requeue leftovers.
640 * Lock status: Assumed that lock is not held upon entry.
642 * Returns: cmd if requeue required, NULL otherwise.
644 * Notes: This is called for block device requests in order to
645 * mark some number of sectors as complete.
647 * We are guaranteeing that the request queue will be goosed
648 * at some point during this call.
649 * Notes: If cmd was requeued, upon return it will be a stale pointer.
651 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
652 int bytes, int requeue)
654 struct request_queue *q = cmd->device->request_queue;
655 struct request *req = cmd->request;
659 * If there are blocks left over at the end, set up the command
660 * to queue the remainder of them.
662 if (end_that_request_chunk(req, uptodate, bytes)) {
663 int leftover = (req->hard_nr_sectors << 9);
665 if (blk_pc_request(req))
666 leftover = req->data_len;
668 /* kill remainder if no retrys */
669 if (!uptodate && blk_noretry_request(req))
670 end_that_request_chunk(req, 0, leftover);
674 * Bleah. Leftovers again. Stick the
675 * leftovers in the front of the
676 * queue, and goose the queue again.
678 scsi_requeue_command(q, cmd);
685 add_disk_randomness(req->rq_disk);
687 spin_lock_irqsave(q->queue_lock, flags);
688 if (blk_rq_tagged(req))
689 blk_queue_end_tag(q, req);
690 end_that_request_last(req, uptodate);
691 spin_unlock_irqrestore(q->queue_lock, flags);
694 * This will goose the queue request function at the end, so we don't
695 * need to worry about launching another command.
697 scsi_next_command(cmd);
701 struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
703 struct scsi_host_sg_pool *sgp;
704 struct scatterlist *sgl;
706 BUG_ON(!cmd->use_sg);
708 switch (cmd->use_sg) {
718 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
722 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
726 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
737 sgp = scsi_sg_pools + cmd->sglist_len;
738 sgl = mempool_alloc(sgp->pool, gfp_mask);
742 EXPORT_SYMBOL(scsi_alloc_sgtable);
744 void scsi_free_sgtable(struct scsi_cmnd *cmd)
746 struct scatterlist *sgl = cmd->request_buffer;
747 struct scsi_host_sg_pool *sgp;
749 BUG_ON(cmd->sglist_len >= SG_MEMPOOL_NR);
751 sgp = scsi_sg_pools + cmd->sglist_len;
752 mempool_free(sgl, sgp->pool);
755 EXPORT_SYMBOL(scsi_free_sgtable);
758 * Function: scsi_release_buffers()
760 * Purpose: Completion processing for block device I/O requests.
762 * Arguments: cmd - command that we are bailing.
764 * Lock status: Assumed that no lock is held upon entry.
768 * Notes: In the event that an upper level driver rejects a
769 * command, we must release resources allocated during
770 * the __init_io() function. Primarily this would involve
771 * the scatter-gather table, and potentially any bounce
774 static void scsi_release_buffers(struct scsi_cmnd *cmd)
777 scsi_free_sgtable(cmd);
780 * Zero these out. They now point to freed memory, and it is
781 * dangerous to hang onto the pointers.
783 cmd->request_buffer = NULL;
784 cmd->request_bufflen = 0;
788 * Function: scsi_io_completion()
790 * Purpose: Completion processing for block device I/O requests.
792 * Arguments: cmd - command that is finished.
794 * Lock status: Assumed that no lock is held upon entry.
798 * Notes: This function is matched in terms of capabilities to
799 * the function that created the scatter-gather list.
800 * In other words, if there are no bounce buffers
801 * (the normal case for most drivers), we don't need
802 * the logic to deal with cleaning up afterwards.
804 * We must do one of several things here:
806 * a) Call scsi_end_request. This will finish off the
807 * specified number of sectors. If we are done, the
808 * command block will be released, and the queue
809 * function will be goosed. If we are not done, then
810 * scsi_end_request will directly goose the queue.
812 * b) We can just use scsi_requeue_command() here. This would
813 * be used if we just wanted to retry, for example.
815 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
817 int result = cmd->result;
818 int this_count = cmd->request_bufflen;
819 struct request_queue *q = cmd->device->request_queue;
820 struct request *req = cmd->request;
821 int clear_errors = 1;
822 struct scsi_sense_hdr sshdr;
824 int sense_deferred = 0;
826 scsi_release_buffers(cmd);
829 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
831 sense_deferred = scsi_sense_is_deferred(&sshdr);
834 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
835 req->errors = result;
838 if (sense_valid && req->sense) {
840 * SG_IO wants current and deferred errors
842 int len = 8 + cmd->sense_buffer[7];
844 if (len > SCSI_SENSE_BUFFERSIZE)
845 len = SCSI_SENSE_BUFFERSIZE;
846 memcpy(req->sense, cmd->sense_buffer, len);
847 req->sense_len = len;
850 req->data_len = cmd->resid;
854 * Next deal with any sectors which we were able to correctly
857 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
859 req->nr_sectors, good_bytes));
860 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
865 /* A number of bytes were successfully read. If there
866 * are leftovers and there is some kind of error
867 * (result != 0), retry the rest.
869 if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL)
872 /* good_bytes = 0, or (inclusive) there were leftovers and
873 * result = 0, so scsi_end_request couldn't retry.
875 if (sense_valid && !sense_deferred) {
876 switch (sshdr.sense_key) {
878 if (cmd->device->removable) {
879 /* Detected disc change. Set a bit
880 * and quietly refuse further access.
882 cmd->device->changed = 1;
883 scsi_end_request(cmd, 0, this_count, 1);
886 /* Must have been a power glitch, or a
887 * bus reset. Could not have been a
888 * media change, so we just retry the
889 * request and see what happens.
891 scsi_requeue_command(q, cmd);
895 case ILLEGAL_REQUEST:
896 /* If we had an ILLEGAL REQUEST returned, then
897 * we may have performed an unsupported
898 * command. The only thing this should be
899 * would be a ten byte read where only a six
900 * byte read was supported. Also, on a system
901 * where READ CAPACITY failed, we may have
902 * read past the end of the disk.
904 if ((cmd->device->use_10_for_rw &&
905 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
906 (cmd->cmnd[0] == READ_10 ||
907 cmd->cmnd[0] == WRITE_10)) {
908 cmd->device->use_10_for_rw = 0;
909 /* This will cause a retry with a
912 scsi_requeue_command(q, cmd);
915 scsi_end_request(cmd, 0, this_count, 1);
920 /* If the device is in the process of becoming
921 * ready, or has a temporary blockage, retry.
923 if (sshdr.asc == 0x04) {
924 switch (sshdr.ascq) {
925 case 0x01: /* becoming ready */
926 case 0x04: /* format in progress */
927 case 0x05: /* rebuild in progress */
928 case 0x06: /* recalculation in progress */
929 case 0x07: /* operation in progress */
930 case 0x08: /* Long write in progress */
931 case 0x09: /* self test in progress */
932 scsi_requeue_command(q, cmd);
938 if (!(req->cmd_flags & REQ_QUIET))
939 scsi_cmd_print_sense_hdr(cmd,
943 scsi_end_request(cmd, 0, this_count, 1);
945 case VOLUME_OVERFLOW:
946 if (!(req->cmd_flags & REQ_QUIET)) {
947 scmd_printk(KERN_INFO, cmd,
948 "Volume overflow, CDB: ");
949 __scsi_print_command(cmd->cmnd);
950 scsi_print_sense("", cmd);
952 /* See SSC3rXX or current. */
953 scsi_end_request(cmd, 0, this_count, 1);
959 if (host_byte(result) == DID_RESET) {
960 /* Third party bus reset or reset for error recovery
961 * reasons. Just retry the request and see what
964 scsi_requeue_command(q, cmd);
968 if (!(req->cmd_flags & REQ_QUIET)) {
969 scsi_print_result(cmd);
970 if (driver_byte(result) & DRIVER_SENSE)
971 scsi_print_sense("", cmd);
974 scsi_end_request(cmd, 0, this_count, !result);
978 * Function: scsi_init_io()
980 * Purpose: SCSI I/O initialize function.
982 * Arguments: cmd - Command descriptor we wish to initialize
984 * Returns: 0 on success
985 * BLKPREP_DEFER if the failure is retryable
986 * BLKPREP_KILL if the failure is fatal
988 static int scsi_init_io(struct scsi_cmnd *cmd)
990 struct request *req = cmd->request;
991 struct scatterlist *sgpnt;
995 * We used to not use scatter-gather for single segment request,
996 * but now we do (it makes highmem I/O easier to support without
999 cmd->use_sg = req->nr_phys_segments;
1002 * If sg table allocation fails, requeue request later.
1004 sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
1005 if (unlikely(!sgpnt)) {
1006 scsi_unprep_request(req);
1007 return BLKPREP_DEFER;
1011 cmd->request_buffer = (char *) sgpnt;
1012 if (blk_pc_request(req))
1013 cmd->request_bufflen = req->data_len;
1015 cmd->request_bufflen = req->nr_sectors << 9;
1018 * Next, walk the list, and fill in the addresses and sizes of
1021 count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
1022 if (likely(count <= cmd->use_sg)) {
1023 cmd->use_sg = count;
1027 printk(KERN_ERR "Incorrect number of segments after building list\n");
1028 printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg);
1029 printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
1030 req->current_nr_sectors);
1032 return BLKPREP_KILL;
1035 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1036 struct request *req)
1038 struct scsi_cmnd *cmd;
1040 if (!req->special) {
1041 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1049 /* pull a tag out of the request if we have one */
1050 cmd->tag = req->tag;
1056 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1058 struct scsi_cmnd *cmd;
1059 int ret = scsi_prep_state_check(sdev, req);
1061 if (ret != BLKPREP_OK)
1064 cmd = scsi_get_cmd_from_req(sdev, req);
1066 return BLKPREP_DEFER;
1069 * BLOCK_PC requests may transfer data, in which case they must
1070 * a bio attached to them. Or they might contain a SCSI command
1071 * that does not transfer data, in which case they may optionally
1072 * submit a request without an attached bio.
1077 BUG_ON(!req->nr_phys_segments);
1079 ret = scsi_init_io(cmd);
1083 BUG_ON(req->data_len);
1086 cmd->request_bufflen = 0;
1087 cmd->request_buffer = NULL;
1092 BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
1093 memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
1094 cmd->cmd_len = req->cmd_len;
1096 cmd->sc_data_direction = DMA_NONE;
1097 else if (rq_data_dir(req) == WRITE)
1098 cmd->sc_data_direction = DMA_TO_DEVICE;
1100 cmd->sc_data_direction = DMA_FROM_DEVICE;
1102 cmd->transfersize = req->data_len;
1103 cmd->allowed = req->retries;
1104 cmd->timeout_per_command = req->timeout;
1107 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
1110 * Setup a REQ_TYPE_FS command. These are simple read/write request
1111 * from filesystems that still need to be translated to SCSI CDBs from
1114 int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1116 struct scsi_cmnd *cmd;
1117 int ret = scsi_prep_state_check(sdev, req);
1119 if (ret != BLKPREP_OK)
1122 * Filesystem requests must transfer data.
1124 BUG_ON(!req->nr_phys_segments);
1126 cmd = scsi_get_cmd_from_req(sdev, req);
1128 return BLKPREP_DEFER;
1130 return scsi_init_io(cmd);
1132 EXPORT_SYMBOL(scsi_setup_fs_cmnd);
1134 int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1136 int ret = BLKPREP_OK;
1139 * If the device is not in running state we will reject some
1142 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1143 switch (sdev->sdev_state) {
1146 * If the device is offline we refuse to process any
1147 * commands. The device must be brought online
1148 * before trying any recovery commands.
1150 sdev_printk(KERN_ERR, sdev,
1151 "rejecting I/O to offline device\n");
1156 * If the device is fully deleted, we refuse to
1157 * process any commands as well.
1159 sdev_printk(KERN_ERR, sdev,
1160 "rejecting I/O to dead device\n");
1166 * If the devices is blocked we defer normal commands.
1168 if (!(req->cmd_flags & REQ_PREEMPT))
1169 ret = BLKPREP_DEFER;
1173 * For any other not fully online state we only allow
1174 * special commands. In particular any user initiated
1175 * command is not allowed.
1177 if (!(req->cmd_flags & REQ_PREEMPT))
1184 EXPORT_SYMBOL(scsi_prep_state_check);
1186 int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1188 struct scsi_device *sdev = q->queuedata;
1192 req->errors = DID_NO_CONNECT << 16;
1193 /* release the command and kill it */
1195 struct scsi_cmnd *cmd = req->special;
1196 scsi_release_buffers(cmd);
1197 scsi_put_command(cmd);
1198 req->special = NULL;
1203 * If we defer, the elv_next_request() returns NULL, but the
1204 * queue must be restarted, so we plug here if no returning
1205 * command will automatically do that.
1207 if (sdev->device_busy == 0)
1211 req->cmd_flags |= REQ_DONTPREP;
1216 EXPORT_SYMBOL(scsi_prep_return);
1218 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1220 struct scsi_device *sdev = q->queuedata;
1221 int ret = BLKPREP_KILL;
1223 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1224 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1225 return scsi_prep_return(q, req, ret);
1229 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1232 * Called with the queue_lock held.
1234 static inline int scsi_dev_queue_ready(struct request_queue *q,
1235 struct scsi_device *sdev)
1237 if (sdev->device_busy >= sdev->queue_depth)
1239 if (sdev->device_busy == 0 && sdev->device_blocked) {
1241 * unblock after device_blocked iterates to zero
1243 if (--sdev->device_blocked == 0) {
1245 sdev_printk(KERN_INFO, sdev,
1246 "unblocking device at zero depth\n"));
1252 if (sdev->device_blocked)
1259 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1260 * return 0. We must end up running the queue again whenever 0 is
1261 * returned, else IO can hang.
1263 * Called with host_lock held.
1265 static inline int scsi_host_queue_ready(struct request_queue *q,
1266 struct Scsi_Host *shost,
1267 struct scsi_device *sdev)
1269 if (scsi_host_in_recovery(shost))
1271 if (shost->host_busy == 0 && shost->host_blocked) {
1273 * unblock after host_blocked iterates to zero
1275 if (--shost->host_blocked == 0) {
1277 printk("scsi%d unblocking host at zero depth\n",
1284 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
1285 shost->host_blocked || shost->host_self_blocked) {
1286 if (list_empty(&sdev->starved_entry))
1287 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1291 /* We're OK to process the command, so we can't be starved */
1292 if (!list_empty(&sdev->starved_entry))
1293 list_del_init(&sdev->starved_entry);
1299 * Kill a request for a dead device
1301 static void scsi_kill_request(struct request *req, struct request_queue *q)
1303 struct scsi_cmnd *cmd = req->special;
1304 struct scsi_device *sdev = cmd->device;
1305 struct Scsi_Host *shost = sdev->host;
1307 blkdev_dequeue_request(req);
1309 if (unlikely(cmd == NULL)) {
1310 printk(KERN_CRIT "impossible request in %s.\n",
1315 scsi_init_cmd_errh(cmd);
1316 cmd->result = DID_NO_CONNECT << 16;
1317 atomic_inc(&cmd->device->iorequest_cnt);
1320 * SCSI request completion path will do scsi_device_unbusy(),
1321 * bump busy counts. To bump the counters, we need to dance
1322 * with the locks as normal issue path does.
1324 sdev->device_busy++;
1325 spin_unlock(sdev->request_queue->queue_lock);
1326 spin_lock(shost->host_lock);
1328 spin_unlock(shost->host_lock);
1329 spin_lock(sdev->request_queue->queue_lock);
1334 static void scsi_softirq_done(struct request *rq)
1336 struct scsi_cmnd *cmd = rq->completion_data;
1337 unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
1340 INIT_LIST_HEAD(&cmd->eh_entry);
1342 disposition = scsi_decide_disposition(cmd);
1343 if (disposition != SUCCESS &&
1344 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1345 sdev_printk(KERN_ERR, cmd->device,
1346 "timing out command, waited %lus\n",
1348 disposition = SUCCESS;
1351 scsi_log_completion(cmd, disposition);
1353 switch (disposition) {
1355 scsi_finish_command(cmd);
1358 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1360 case ADD_TO_MLQUEUE:
1361 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1364 if (!scsi_eh_scmd_add(cmd, 0))
1365 scsi_finish_command(cmd);
1370 * Function: scsi_request_fn()
1372 * Purpose: Main strategy routine for SCSI.
1374 * Arguments: q - Pointer to actual queue.
1378 * Lock status: IO request lock assumed to be held when called.
1380 static void scsi_request_fn(struct request_queue *q)
1382 struct scsi_device *sdev = q->queuedata;
1383 struct Scsi_Host *shost;
1384 struct scsi_cmnd *cmd;
1385 struct request *req;
1388 printk("scsi: killing requests for dead queue\n");
1389 while ((req = elv_next_request(q)) != NULL)
1390 scsi_kill_request(req, q);
1394 if(!get_device(&sdev->sdev_gendev))
1395 /* We must be tearing the block queue down already */
1399 * To start with, we keep looping until the queue is empty, or until
1400 * the host is no longer able to accept any more requests.
1403 while (!blk_queue_plugged(q)) {
1406 * get next queueable request. We do this early to make sure
1407 * that the request is fully prepared even if we cannot
1410 req = elv_next_request(q);
1411 if (!req || !scsi_dev_queue_ready(q, sdev))
1414 if (unlikely(!scsi_device_online(sdev))) {
1415 sdev_printk(KERN_ERR, sdev,
1416 "rejecting I/O to offline device\n");
1417 scsi_kill_request(req, q);
1423 * Remove the request from the request list.
1425 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1426 blkdev_dequeue_request(req);
1427 sdev->device_busy++;
1429 spin_unlock(q->queue_lock);
1431 if (unlikely(cmd == NULL)) {
1432 printk(KERN_CRIT "impossible request in %s.\n"
1433 "please mail a stack trace to "
1434 "linux-scsi@vger.kernel.org\n",
1436 blk_dump_rq_flags(req, "foo");
1439 spin_lock(shost->host_lock);
1441 if (!scsi_host_queue_ready(q, shost, sdev))
1443 if (sdev->single_lun) {
1444 if (scsi_target(sdev)->starget_sdev_user &&
1445 scsi_target(sdev)->starget_sdev_user != sdev)
1447 scsi_target(sdev)->starget_sdev_user = sdev;
1452 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1453 * take the lock again.
1455 spin_unlock_irq(shost->host_lock);
1458 * Finally, initialize any error handling parameters, and set up
1459 * the timers for timeouts.
1461 scsi_init_cmd_errh(cmd);
1464 * Dispatch the command to the low-level driver.
1466 rtn = scsi_dispatch_cmd(cmd);
1467 spin_lock_irq(q->queue_lock);
1469 /* we're refusing the command; because of
1470 * the way locks get dropped, we need to
1471 * check here if plugging is required */
1472 if(sdev->device_busy == 0)
1482 spin_unlock_irq(shost->host_lock);
1485 * lock q, handle tag, requeue req, and decrement device_busy. We
1486 * must return with queue_lock held.
1488 * Decrementing device_busy without checking it is OK, as all such
1489 * cases (host limits or settings) should run the queue at some
1492 spin_lock_irq(q->queue_lock);
1493 blk_requeue_request(q, req);
1494 sdev->device_busy--;
1495 if(sdev->device_busy == 0)
1498 /* must be careful here...if we trigger the ->remove() function
1499 * we cannot be holding the q lock */
1500 spin_unlock_irq(q->queue_lock);
1501 put_device(&sdev->sdev_gendev);
1502 spin_lock_irq(q->queue_lock);
1505 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1507 struct device *host_dev;
1508 u64 bounce_limit = 0xffffffff;
1510 if (shost->unchecked_isa_dma)
1511 return BLK_BOUNCE_ISA;
1513 * Platforms with virtual-DMA translation
1514 * hardware have no practical limit.
1516 if (!PCI_DMA_BUS_IS_PHYS)
1517 return BLK_BOUNCE_ANY;
1519 host_dev = scsi_get_device(shost);
1520 if (host_dev && host_dev->dma_mask)
1521 bounce_limit = *host_dev->dma_mask;
1523 return bounce_limit;
1525 EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1527 struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1528 request_fn_proc *request_fn)
1530 struct request_queue *q;
1532 q = blk_init_queue(request_fn, NULL);
1536 blk_queue_max_hw_segments(q, shost->sg_tablesize);
1537 blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS);
1538 blk_queue_max_sectors(q, shost->max_sectors);
1539 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1540 blk_queue_segment_boundary(q, shost->dma_boundary);
1542 if (!shost->use_clustering)
1543 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
1546 EXPORT_SYMBOL(__scsi_alloc_queue);
1548 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1550 struct request_queue *q;
1552 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1556 blk_queue_prep_rq(q, scsi_prep_fn);
1557 blk_queue_softirq_done(q, scsi_softirq_done);
1561 void scsi_free_queue(struct request_queue *q)
1563 blk_cleanup_queue(q);
1567 * Function: scsi_block_requests()
1569 * Purpose: Utility function used by low-level drivers to prevent further
1570 * commands from being queued to the device.
1572 * Arguments: shost - Host in question
1576 * Lock status: No locks are assumed held.
1578 * Notes: There is no timer nor any other means by which the requests
1579 * get unblocked other than the low-level driver calling
1580 * scsi_unblock_requests().
1582 void scsi_block_requests(struct Scsi_Host *shost)
1584 shost->host_self_blocked = 1;
1586 EXPORT_SYMBOL(scsi_block_requests);
1589 * Function: scsi_unblock_requests()
1591 * Purpose: Utility function used by low-level drivers to allow further
1592 * commands from being queued to the device.
1594 * Arguments: shost - Host in question
1598 * Lock status: No locks are assumed held.
1600 * Notes: There is no timer nor any other means by which the requests
1601 * get unblocked other than the low-level driver calling
1602 * scsi_unblock_requests().
1604 * This is done as an API function so that changes to the
1605 * internals of the scsi mid-layer won't require wholesale
1606 * changes to drivers that use this feature.
1608 void scsi_unblock_requests(struct Scsi_Host *shost)
1610 shost->host_self_blocked = 0;
1611 scsi_run_host_queues(shost);
1613 EXPORT_SYMBOL(scsi_unblock_requests);
1615 int __init scsi_init_queue(void)
1619 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1620 sizeof(struct scsi_io_context),
1622 if (!scsi_io_context_cache) {
1623 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1627 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1628 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1629 int size = sgp->size * sizeof(struct scatterlist);
1631 sgp->slab = kmem_cache_create(sgp->name, size, 0,
1632 SLAB_HWCACHE_ALIGN, NULL);
1634 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1638 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1641 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1649 void scsi_exit_queue(void)
1653 kmem_cache_destroy(scsi_io_context_cache);
1655 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1656 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1657 mempool_destroy(sgp->pool);
1658 kmem_cache_destroy(sgp->slab);
1663 * scsi_mode_select - issue a mode select
1664 * @sdev: SCSI device to be queried
1665 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1666 * @sp: Save page bit (0 == don't save, 1 == save)
1667 * @modepage: mode page being requested
1668 * @buffer: request buffer (may not be smaller than eight bytes)
1669 * @len: length of request buffer.
1670 * @timeout: command timeout
1671 * @retries: number of retries before failing
1672 * @data: returns a structure abstracting the mode header data
1673 * @sense: place to put sense data (or NULL if no sense to be collected).
1674 * must be SCSI_SENSE_BUFFERSIZE big.
1676 * Returns zero if successful; negative error number or scsi
1681 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1682 unsigned char *buffer, int len, int timeout, int retries,
1683 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1685 unsigned char cmd[10];
1686 unsigned char *real_buffer;
1689 memset(cmd, 0, sizeof(cmd));
1690 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1692 if (sdev->use_10_for_ms) {
1695 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1698 memcpy(real_buffer + 8, buffer, len);
1702 real_buffer[2] = data->medium_type;
1703 real_buffer[3] = data->device_specific;
1704 real_buffer[4] = data->longlba ? 0x01 : 0;
1706 real_buffer[6] = data->block_descriptor_length >> 8;
1707 real_buffer[7] = data->block_descriptor_length;
1709 cmd[0] = MODE_SELECT_10;
1713 if (len > 255 || data->block_descriptor_length > 255 ||
1717 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1720 memcpy(real_buffer + 4, buffer, len);
1723 real_buffer[1] = data->medium_type;
1724 real_buffer[2] = data->device_specific;
1725 real_buffer[3] = data->block_descriptor_length;
1728 cmd[0] = MODE_SELECT;
1732 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1733 sshdr, timeout, retries);
1737 EXPORT_SYMBOL_GPL(scsi_mode_select);
1740 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1741 * six bytes if necessary.
1742 * @sdev: SCSI device to be queried
1743 * @dbd: set if mode sense will allow block descriptors to be returned
1744 * @modepage: mode page being requested
1745 * @buffer: request buffer (may not be smaller than eight bytes)
1746 * @len: length of request buffer.
1747 * @timeout: command timeout
1748 * @retries: number of retries before failing
1749 * @data: returns a structure abstracting the mode header data
1750 * @sense: place to put sense data (or NULL if no sense to be collected).
1751 * must be SCSI_SENSE_BUFFERSIZE big.
1753 * Returns zero if unsuccessful, or the header offset (either 4
1754 * or 8 depending on whether a six or ten byte command was
1755 * issued) if successful.
1758 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
1759 unsigned char *buffer, int len, int timeout, int retries,
1760 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1762 unsigned char cmd[12];
1766 struct scsi_sense_hdr my_sshdr;
1768 memset(data, 0, sizeof(*data));
1769 memset(&cmd[0], 0, 12);
1770 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1773 /* caller might not be interested in sense, but we need it */
1778 use_10_for_ms = sdev->use_10_for_ms;
1780 if (use_10_for_ms) {
1784 cmd[0] = MODE_SENSE_10;
1791 cmd[0] = MODE_SENSE;
1796 memset(buffer, 0, len);
1798 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1799 sshdr, timeout, retries);
1801 /* This code looks awful: what it's doing is making sure an
1802 * ILLEGAL REQUEST sense return identifies the actual command
1803 * byte as the problem. MODE_SENSE commands can return
1804 * ILLEGAL REQUEST if the code page isn't supported */
1806 if (use_10_for_ms && !scsi_status_is_good(result) &&
1807 (driver_byte(result) & DRIVER_SENSE)) {
1808 if (scsi_sense_valid(sshdr)) {
1809 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1810 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
1812 * Invalid command operation code
1814 sdev->use_10_for_ms = 0;
1820 if(scsi_status_is_good(result)) {
1821 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1822 (modepage == 6 || modepage == 8))) {
1823 /* Initio breakage? */
1826 data->medium_type = 0;
1827 data->device_specific = 0;
1829 data->block_descriptor_length = 0;
1830 } else if(use_10_for_ms) {
1831 data->length = buffer[0]*256 + buffer[1] + 2;
1832 data->medium_type = buffer[2];
1833 data->device_specific = buffer[3];
1834 data->longlba = buffer[4] & 0x01;
1835 data->block_descriptor_length = buffer[6]*256
1838 data->length = buffer[0] + 1;
1839 data->medium_type = buffer[1];
1840 data->device_specific = buffer[2];
1841 data->block_descriptor_length = buffer[3];
1843 data->header_length = header_length;
1848 EXPORT_SYMBOL(scsi_mode_sense);
1851 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries)
1854 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1856 struct scsi_sense_hdr sshdr;
1859 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr,
1862 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
1864 if ((scsi_sense_valid(&sshdr)) &&
1865 ((sshdr.sense_key == UNIT_ATTENTION) ||
1866 (sshdr.sense_key == NOT_READY))) {
1873 EXPORT_SYMBOL(scsi_test_unit_ready);
1876 * scsi_device_set_state - Take the given device through the device
1878 * @sdev: scsi device to change the state of.
1879 * @state: state to change to.
1881 * Returns zero if unsuccessful or an error if the requested
1882 * transition is illegal.
1885 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
1887 enum scsi_device_state oldstate = sdev->sdev_state;
1889 if (state == oldstate)
1894 /* There are no legal states that come back to
1895 * created. This is the manually initialised start
1969 sdev->sdev_state = state;
1973 SCSI_LOG_ERROR_RECOVERY(1,
1974 sdev_printk(KERN_ERR, sdev,
1975 "Illegal state transition %s->%s\n",
1976 scsi_device_state_name(oldstate),
1977 scsi_device_state_name(state))
1981 EXPORT_SYMBOL(scsi_device_set_state);
1984 * scsi_device_quiesce - Block user issued commands.
1985 * @sdev: scsi device to quiesce.
1987 * This works by trying to transition to the SDEV_QUIESCE state
1988 * (which must be a legal transition). When the device is in this
1989 * state, only special requests will be accepted, all others will
1990 * be deferred. Since special requests may also be requeued requests,
1991 * a successful return doesn't guarantee the device will be
1992 * totally quiescent.
1994 * Must be called with user context, may sleep.
1996 * Returns zero if unsuccessful or an error if not.
1999 scsi_device_quiesce(struct scsi_device *sdev)
2001 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2005 scsi_run_queue(sdev->request_queue);
2006 while (sdev->device_busy) {
2007 msleep_interruptible(200);
2008 scsi_run_queue(sdev->request_queue);
2012 EXPORT_SYMBOL(scsi_device_quiesce);
2015 * scsi_device_resume - Restart user issued commands to a quiesced device.
2016 * @sdev: scsi device to resume.
2018 * Moves the device from quiesced back to running and restarts the
2021 * Must be called with user context, may sleep.
2024 scsi_device_resume(struct scsi_device *sdev)
2026 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2028 scsi_run_queue(sdev->request_queue);
2030 EXPORT_SYMBOL(scsi_device_resume);
2033 device_quiesce_fn(struct scsi_device *sdev, void *data)
2035 scsi_device_quiesce(sdev);
2039 scsi_target_quiesce(struct scsi_target *starget)
2041 starget_for_each_device(starget, NULL, device_quiesce_fn);
2043 EXPORT_SYMBOL(scsi_target_quiesce);
2046 device_resume_fn(struct scsi_device *sdev, void *data)
2048 scsi_device_resume(sdev);
2052 scsi_target_resume(struct scsi_target *starget)
2054 starget_for_each_device(starget, NULL, device_resume_fn);
2056 EXPORT_SYMBOL(scsi_target_resume);
2059 * scsi_internal_device_block - internal function to put a device
2060 * temporarily into the SDEV_BLOCK state
2061 * @sdev: device to block
2063 * Block request made by scsi lld's to temporarily stop all
2064 * scsi commands on the specified device. Called from interrupt
2065 * or normal process context.
2067 * Returns zero if successful or error if not
2070 * This routine transitions the device to the SDEV_BLOCK state
2071 * (which must be a legal transition). When the device is in this
2072 * state, all commands are deferred until the scsi lld reenables
2073 * the device with scsi_device_unblock or device_block_tmo fires.
2074 * This routine assumes the host_lock is held on entry.
2077 scsi_internal_device_block(struct scsi_device *sdev)
2079 struct request_queue *q = sdev->request_queue;
2080 unsigned long flags;
2083 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2088 * The device has transitioned to SDEV_BLOCK. Stop the
2089 * block layer from calling the midlayer with this device's
2092 spin_lock_irqsave(q->queue_lock, flags);
2094 spin_unlock_irqrestore(q->queue_lock, flags);
2098 EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2101 * scsi_internal_device_unblock - resume a device after a block request
2102 * @sdev: device to resume
2104 * Called by scsi lld's or the midlayer to restart the device queue
2105 * for the previously suspended scsi device. Called from interrupt or
2106 * normal process context.
2108 * Returns zero if successful or error if not.
2111 * This routine transitions the device to the SDEV_RUNNING state
2112 * (which must be a legal transition) allowing the midlayer to
2113 * goose the queue for this device. This routine assumes the
2114 * host_lock is held upon entry.
2117 scsi_internal_device_unblock(struct scsi_device *sdev)
2119 struct request_queue *q = sdev->request_queue;
2121 unsigned long flags;
2124 * Try to transition the scsi device to SDEV_RUNNING
2125 * and goose the device queue if successful.
2127 err = scsi_device_set_state(sdev, SDEV_RUNNING);
2131 spin_lock_irqsave(q->queue_lock, flags);
2133 spin_unlock_irqrestore(q->queue_lock, flags);
2137 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2140 device_block(struct scsi_device *sdev, void *data)
2142 scsi_internal_device_block(sdev);
2146 target_block(struct device *dev, void *data)
2148 if (scsi_is_target_device(dev))
2149 starget_for_each_device(to_scsi_target(dev), NULL,
2155 scsi_target_block(struct device *dev)
2157 if (scsi_is_target_device(dev))
2158 starget_for_each_device(to_scsi_target(dev), NULL,
2161 device_for_each_child(dev, NULL, target_block);
2163 EXPORT_SYMBOL_GPL(scsi_target_block);
2166 device_unblock(struct scsi_device *sdev, void *data)
2168 scsi_internal_device_unblock(sdev);
2172 target_unblock(struct device *dev, void *data)
2174 if (scsi_is_target_device(dev))
2175 starget_for_each_device(to_scsi_target(dev), NULL,
2181 scsi_target_unblock(struct device *dev)
2183 if (scsi_is_target_device(dev))
2184 starget_for_each_device(to_scsi_target(dev), NULL,
2187 device_for_each_child(dev, NULL, target_unblock);
2189 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2192 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2193 * @sg: scatter-gather list
2194 * @sg_count: number of segments in sg
2195 * @offset: offset in bytes into sg, on return offset into the mapped area
2196 * @len: bytes to map, on return number of bytes mapped
2198 * Returns virtual address of the start of the mapped page
2200 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2201 size_t *offset, size_t *len)
2204 size_t sg_len = 0, len_complete = 0;
2205 struct scatterlist *sg;
2208 WARN_ON(!irqs_disabled());
2210 for_each_sg(sgl, sg, sg_count, i) {
2211 len_complete = sg_len; /* Complete sg-entries */
2212 sg_len += sg->length;
2213 if (sg_len > *offset)
2217 if (unlikely(i == sg_count)) {
2218 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2220 __FUNCTION__, sg_len, *offset, sg_count);
2225 /* Offset starting from the beginning of first page in this sg-entry */
2226 *offset = *offset - len_complete + sg->offset;
2228 /* Assumption: contiguous pages can be accessed as "page + i" */
2229 page = nth_page(sg->page, (*offset >> PAGE_SHIFT));
2230 *offset &= ~PAGE_MASK;
2232 /* Bytes in this sg-entry from *offset to the end of the page */
2233 sg_len = PAGE_SIZE - *offset;
2237 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2239 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2242 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2243 * mapped with scsi_kmap_atomic_sg
2244 * @virt: virtual address to be unmapped
2246 void scsi_kunmap_atomic_sg(void *virt)
2248 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2250 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);