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 2
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 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);
266 return blk_rq_append_bio(q, rq, bio);
269 static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error)
279 * scsi_req_map_sg - map a scatterlist into a request
280 * @rq: request to fill
282 * @nsegs: number of elements
283 * @bufflen: len of buffer
284 * @gfp: memory allocation flags
286 * scsi_req_map_sg maps a scatterlist into a request so that the
287 * request can be sent to the block layer. We do not trust the scatterlist
288 * sent to use, as some ULDs use that struct to only organize the pages.
290 static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
291 int nsegs, unsigned bufflen, gfp_t gfp)
293 struct request_queue *q = rq->q;
294 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
295 unsigned int data_len = 0, len, bytes, off;
297 struct bio *bio = NULL;
298 int i, err, nr_vecs = 0;
300 for (i = 0; i < nsegs; i++) {
307 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
310 nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
313 bio = bio_alloc(gfp, nr_vecs);
318 bio->bi_end_io = scsi_bi_endio;
321 if (bio_add_pc_page(q, bio, page, bytes, off) !=
328 if (bio->bi_vcnt >= nr_vecs) {
329 err = scsi_merge_bio(rq, bio);
331 bio_endio(bio, bio->bi_size, 0);
343 rq->buffer = rq->data = NULL;
344 rq->data_len = data_len;
348 while ((bio = rq->bio) != NULL) {
349 rq->bio = bio->bi_next;
351 * call endio instead of bio_put incase it was bounced
353 bio_endio(bio, bio->bi_size, 0);
360 * scsi_execute_async - insert request
363 * @cmd_len: length of scsi cdb
364 * @data_direction: data direction
365 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
366 * @bufflen: len of buffer
367 * @use_sg: if buffer is a scatterlist this is the number of elements
368 * @timeout: request timeout in seconds
369 * @retries: number of times to retry request
370 * @flags: or into request flags
372 int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
373 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
374 int use_sg, int timeout, int retries, void *privdata,
375 void (*done)(void *, char *, int, int), gfp_t gfp)
378 struct scsi_io_context *sioc;
380 int write = (data_direction == DMA_TO_DEVICE);
382 sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
384 return DRIVER_ERROR << 24;
386 req = blk_get_request(sdev->request_queue, write, gfp);
389 req->cmd_type = REQ_TYPE_BLOCK_PC;
390 req->cmd_flags |= REQ_QUIET;
393 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
395 err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
400 req->cmd_len = cmd_len;
401 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
402 memcpy(req->cmd, cmd, req->cmd_len);
403 req->sense = sioc->sense;
405 req->timeout = timeout;
406 req->retries = retries;
407 req->end_io_data = sioc;
409 sioc->data = privdata;
412 blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
416 blk_put_request(req);
418 kmem_cache_free(scsi_io_context_cache, sioc);
419 return DRIVER_ERROR << 24;
421 EXPORT_SYMBOL_GPL(scsi_execute_async);
424 * Function: scsi_init_cmd_errh()
426 * Purpose: Initialize cmd fields related to error handling.
428 * Arguments: cmd - command that is ready to be queued.
430 * Notes: This function has the job of initializing a number of
431 * fields related to error handling. Typically this will
432 * be called once for each command, as required.
434 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
436 cmd->serial_number = 0;
437 memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer);
438 if (cmd->cmd_len == 0)
439 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
442 void scsi_device_unbusy(struct scsi_device *sdev)
444 struct Scsi_Host *shost = sdev->host;
447 spin_lock_irqsave(shost->host_lock, flags);
449 if (unlikely(scsi_host_in_recovery(shost) &&
450 (shost->host_failed || shost->host_eh_scheduled)))
451 scsi_eh_wakeup(shost);
452 spin_unlock(shost->host_lock);
453 spin_lock(sdev->request_queue->queue_lock);
455 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
459 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
460 * and call blk_run_queue for all the scsi_devices on the target -
461 * including current_sdev first.
463 * Called with *no* scsi locks held.
465 static void scsi_single_lun_run(struct scsi_device *current_sdev)
467 struct Scsi_Host *shost = current_sdev->host;
468 struct scsi_device *sdev, *tmp;
469 struct scsi_target *starget = scsi_target(current_sdev);
472 spin_lock_irqsave(shost->host_lock, flags);
473 starget->starget_sdev_user = NULL;
474 spin_unlock_irqrestore(shost->host_lock, flags);
477 * Call blk_run_queue for all LUNs on the target, starting with
478 * current_sdev. We race with others (to set starget_sdev_user),
479 * but in most cases, we will be first. Ideally, each LU on the
480 * target would get some limited time or requests on the target.
482 blk_run_queue(current_sdev->request_queue);
484 spin_lock_irqsave(shost->host_lock, flags);
485 if (starget->starget_sdev_user)
487 list_for_each_entry_safe(sdev, tmp, &starget->devices,
488 same_target_siblings) {
489 if (sdev == current_sdev)
491 if (scsi_device_get(sdev))
494 spin_unlock_irqrestore(shost->host_lock, flags);
495 blk_run_queue(sdev->request_queue);
496 spin_lock_irqsave(shost->host_lock, flags);
498 scsi_device_put(sdev);
501 spin_unlock_irqrestore(shost->host_lock, flags);
505 * Function: scsi_run_queue()
507 * Purpose: Select a proper request queue to serve next
509 * Arguments: q - last request's queue
513 * Notes: The previous command was completely finished, start
514 * a new one if possible.
516 static void scsi_run_queue(struct request_queue *q)
518 struct scsi_device *sdev = q->queuedata;
519 struct Scsi_Host *shost = sdev->host;
522 if (sdev->single_lun)
523 scsi_single_lun_run(sdev);
525 spin_lock_irqsave(shost->host_lock, flags);
526 while (!list_empty(&shost->starved_list) &&
527 !shost->host_blocked && !shost->host_self_blocked &&
528 !((shost->can_queue > 0) &&
529 (shost->host_busy >= shost->can_queue))) {
531 * As long as shost is accepting commands and we have
532 * starved queues, call blk_run_queue. scsi_request_fn
533 * drops the queue_lock and can add us back to the
536 * host_lock protects the starved_list and starved_entry.
537 * scsi_request_fn must get the host_lock before checking
538 * or modifying starved_list or starved_entry.
540 sdev = list_entry(shost->starved_list.next,
541 struct scsi_device, starved_entry);
542 list_del_init(&sdev->starved_entry);
543 spin_unlock_irqrestore(shost->host_lock, flags);
546 if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) &&
547 !test_and_set_bit(QUEUE_FLAG_REENTER,
548 &sdev->request_queue->queue_flags)) {
549 blk_run_queue(sdev->request_queue);
550 clear_bit(QUEUE_FLAG_REENTER,
551 &sdev->request_queue->queue_flags);
553 blk_run_queue(sdev->request_queue);
555 spin_lock_irqsave(shost->host_lock, flags);
556 if (unlikely(!list_empty(&sdev->starved_entry)))
558 * sdev lost a race, and was put back on the
559 * starved list. This is unlikely but without this
560 * in theory we could loop forever.
564 spin_unlock_irqrestore(shost->host_lock, flags);
570 * Function: scsi_requeue_command()
572 * Purpose: Handle post-processing of completed commands.
574 * Arguments: q - queue to operate on
575 * cmd - command that may need to be requeued.
579 * Notes: After command completion, there may be blocks left
580 * over which weren't finished by the previous command
581 * this can be for a number of reasons - the main one is
582 * I/O errors in the middle of the request, in which case
583 * we need to request the blocks that come after the bad
585 * Notes: Upon return, cmd is a stale pointer.
587 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
589 struct request *req = cmd->request;
592 scsi_unprep_request(req);
593 spin_lock_irqsave(q->queue_lock, flags);
594 blk_requeue_request(q, req);
595 spin_unlock_irqrestore(q->queue_lock, flags);
600 void scsi_next_command(struct scsi_cmnd *cmd)
602 struct scsi_device *sdev = cmd->device;
603 struct request_queue *q = sdev->request_queue;
605 /* need to hold a reference on the device before we let go of the cmd */
606 get_device(&sdev->sdev_gendev);
608 scsi_put_command(cmd);
611 /* ok to remove device now */
612 put_device(&sdev->sdev_gendev);
615 void scsi_run_host_queues(struct Scsi_Host *shost)
617 struct scsi_device *sdev;
619 shost_for_each_device(sdev, shost)
620 scsi_run_queue(sdev->request_queue);
624 * Function: scsi_end_request()
626 * Purpose: Post-processing of completed commands (usually invoked at end
627 * of upper level post-processing and scsi_io_completion).
629 * Arguments: cmd - command that is complete.
630 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
631 * bytes - number of bytes of completed I/O
632 * requeue - indicates whether we should requeue leftovers.
634 * Lock status: Assumed that lock is not held upon entry.
636 * Returns: cmd if requeue required, NULL otherwise.
638 * Notes: This is called for block device requests in order to
639 * mark some number of sectors as complete.
641 * We are guaranteeing that the request queue will be goosed
642 * at some point during this call.
643 * Notes: If cmd was requeued, upon return it will be a stale pointer.
645 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
646 int bytes, int requeue)
648 struct request_queue *q = cmd->device->request_queue;
649 struct request *req = cmd->request;
653 * If there are blocks left over at the end, set up the command
654 * to queue the remainder of them.
656 if (end_that_request_chunk(req, uptodate, bytes)) {
657 int leftover = (req->hard_nr_sectors << 9);
659 if (blk_pc_request(req))
660 leftover = req->data_len;
662 /* kill remainder if no retrys */
663 if (!uptodate && blk_noretry_request(req))
664 end_that_request_chunk(req, 0, leftover);
668 * Bleah. Leftovers again. Stick the
669 * leftovers in the front of the
670 * queue, and goose the queue again.
672 scsi_requeue_command(q, cmd);
679 add_disk_randomness(req->rq_disk);
681 spin_lock_irqsave(q->queue_lock, flags);
682 if (blk_rq_tagged(req))
683 blk_queue_end_tag(q, req);
684 end_that_request_last(req, uptodate);
685 spin_unlock_irqrestore(q->queue_lock, flags);
688 * This will goose the queue request function at the end, so we don't
689 * need to worry about launching another command.
691 scsi_next_command(cmd);
695 struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
697 struct scsi_host_sg_pool *sgp;
698 struct scatterlist *sgl;
700 BUG_ON(!cmd->use_sg);
702 switch (cmd->use_sg) {
712 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
716 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
720 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
731 sgp = scsi_sg_pools + cmd->sglist_len;
732 sgl = mempool_alloc(sgp->pool, gfp_mask);
736 EXPORT_SYMBOL(scsi_alloc_sgtable);
738 void scsi_free_sgtable(struct scatterlist *sgl, int index)
740 struct scsi_host_sg_pool *sgp;
742 BUG_ON(index >= SG_MEMPOOL_NR);
744 sgp = scsi_sg_pools + index;
745 mempool_free(sgl, sgp->pool);
748 EXPORT_SYMBOL(scsi_free_sgtable);
751 * Function: scsi_release_buffers()
753 * Purpose: Completion processing for block device I/O requests.
755 * Arguments: cmd - command that we are bailing.
757 * Lock status: Assumed that no lock is held upon entry.
761 * Notes: In the event that an upper level driver rejects a
762 * command, we must release resources allocated during
763 * the __init_io() function. Primarily this would involve
764 * the scatter-gather table, and potentially any bounce
767 static void scsi_release_buffers(struct scsi_cmnd *cmd)
770 scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
773 * Zero these out. They now point to freed memory, and it is
774 * dangerous to hang onto the pointers.
776 cmd->request_buffer = NULL;
777 cmd->request_bufflen = 0;
781 * Function: scsi_io_completion()
783 * Purpose: Completion processing for block device I/O requests.
785 * Arguments: cmd - command that is finished.
787 * Lock status: Assumed that no lock is held upon entry.
791 * Notes: This function is matched in terms of capabilities to
792 * the function that created the scatter-gather list.
793 * In other words, if there are no bounce buffers
794 * (the normal case for most drivers), we don't need
795 * the logic to deal with cleaning up afterwards.
797 * We must do one of several things here:
799 * a) Call scsi_end_request. This will finish off the
800 * specified number of sectors. If we are done, the
801 * command block will be released, and the queue
802 * function will be goosed. If we are not done, then
803 * scsi_end_request will directly goose the queue.
805 * b) We can just use scsi_requeue_command() here. This would
806 * be used if we just wanted to retry, for example.
808 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
810 int result = cmd->result;
811 int this_count = cmd->request_bufflen;
812 struct request_queue *q = cmd->device->request_queue;
813 struct request *req = cmd->request;
814 int clear_errors = 1;
815 struct scsi_sense_hdr sshdr;
817 int sense_deferred = 0;
819 scsi_release_buffers(cmd);
822 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
824 sense_deferred = scsi_sense_is_deferred(&sshdr);
827 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
828 req->errors = result;
831 if (sense_valid && req->sense) {
833 * SG_IO wants current and deferred errors
835 int len = 8 + cmd->sense_buffer[7];
837 if (len > SCSI_SENSE_BUFFERSIZE)
838 len = SCSI_SENSE_BUFFERSIZE;
839 memcpy(req->sense, cmd->sense_buffer, len);
840 req->sense_len = len;
843 req->data_len = cmd->resid;
847 * Next deal with any sectors which we were able to correctly
850 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
852 req->nr_sectors, good_bytes));
853 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
858 /* A number of bytes were successfully read. If there
859 * are leftovers and there is some kind of error
860 * (result != 0), retry the rest.
862 if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL)
865 /* good_bytes = 0, or (inclusive) there were leftovers and
866 * result = 0, so scsi_end_request couldn't retry.
868 if (sense_valid && !sense_deferred) {
869 switch (sshdr.sense_key) {
871 if (cmd->device->removable) {
872 /* Detected disc change. Set a bit
873 * and quietly refuse further access.
875 cmd->device->changed = 1;
876 scsi_end_request(cmd, 0, this_count, 1);
879 /* Must have been a power glitch, or a
880 * bus reset. Could not have been a
881 * media change, so we just retry the
882 * request and see what happens.
884 scsi_requeue_command(q, cmd);
888 case ILLEGAL_REQUEST:
889 /* If we had an ILLEGAL REQUEST returned, then
890 * we may have performed an unsupported
891 * command. The only thing this should be
892 * would be a ten byte read where only a six
893 * byte read was supported. Also, on a system
894 * where READ CAPACITY failed, we may have
895 * read past the end of the disk.
897 if ((cmd->device->use_10_for_rw &&
898 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
899 (cmd->cmnd[0] == READ_10 ||
900 cmd->cmnd[0] == WRITE_10)) {
901 cmd->device->use_10_for_rw = 0;
902 /* This will cause a retry with a
905 scsi_requeue_command(q, cmd);
908 scsi_end_request(cmd, 0, this_count, 1);
913 /* If the device is in the process of becoming
914 * ready, or has a temporary blockage, retry.
916 if (sshdr.asc == 0x04) {
917 switch (sshdr.ascq) {
918 case 0x01: /* becoming ready */
919 case 0x04: /* format in progress */
920 case 0x05: /* rebuild in progress */
921 case 0x06: /* recalculation in progress */
922 case 0x07: /* operation in progress */
923 case 0x08: /* Long write in progress */
924 case 0x09: /* self test in progress */
925 scsi_requeue_command(q, cmd);
931 if (!(req->cmd_flags & REQ_QUIET)) {
932 scmd_printk(KERN_INFO, cmd,
933 "Device not ready: ");
934 scsi_print_sense_hdr("", &sshdr);
936 scsi_end_request(cmd, 0, this_count, 1);
938 case VOLUME_OVERFLOW:
939 if (!(req->cmd_flags & REQ_QUIET)) {
940 scmd_printk(KERN_INFO, cmd,
941 "Volume overflow, CDB: ");
942 __scsi_print_command(cmd->cmnd);
943 scsi_print_sense("", cmd);
945 /* See SSC3rXX or current. */
946 scsi_end_request(cmd, 0, this_count, 1);
952 if (host_byte(result) == DID_RESET) {
953 /* Third party bus reset or reset for error recovery
954 * reasons. Just retry the request and see what
957 scsi_requeue_command(q, cmd);
961 if (!(req->cmd_flags & REQ_QUIET)) {
962 scsi_print_result(cmd);
963 if (driver_byte(result) & DRIVER_SENSE)
964 scsi_print_sense("", cmd);
967 scsi_end_request(cmd, 0, this_count, !result);
969 EXPORT_SYMBOL(scsi_io_completion);
972 * Function: scsi_init_io()
974 * Purpose: SCSI I/O initialize function.
976 * Arguments: cmd - Command descriptor we wish to initialize
978 * Returns: 0 on success
979 * BLKPREP_DEFER if the failure is retryable
980 * BLKPREP_KILL if the failure is fatal
982 static int scsi_init_io(struct scsi_cmnd *cmd)
984 struct request *req = cmd->request;
985 struct scatterlist *sgpnt;
989 * We used to not use scatter-gather for single segment request,
990 * but now we do (it makes highmem I/O easier to support without
993 cmd->use_sg = req->nr_phys_segments;
996 * If sg table allocation fails, requeue request later.
998 sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
999 if (unlikely(!sgpnt)) {
1000 scsi_unprep_request(req);
1001 return BLKPREP_DEFER;
1005 cmd->request_buffer = (char *) sgpnt;
1006 if (blk_pc_request(req))
1007 cmd->request_bufflen = req->data_len;
1009 cmd->request_bufflen = req->nr_sectors << 9;
1012 * Next, walk the list, and fill in the addresses and sizes of
1015 count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
1016 if (likely(count <= cmd->use_sg)) {
1017 cmd->use_sg = count;
1021 printk(KERN_ERR "Incorrect number of segments after building list\n");
1022 printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg);
1023 printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
1024 req->current_nr_sectors);
1026 /* release the command and kill it */
1027 scsi_release_buffers(cmd);
1028 scsi_put_command(cmd);
1029 return BLKPREP_KILL;
1032 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1033 struct request *req)
1035 struct scsi_cmnd *cmd;
1037 if (!req->special) {
1038 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1046 /* pull a tag out of the request if we have one */
1047 cmd->tag = req->tag;
1053 static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
1055 BUG_ON(!blk_pc_request(cmd->request));
1057 * This will complete the whole command with uptodate=1 so
1058 * as far as the block layer is concerned the command completed
1059 * successfully. Since this is a REQ_BLOCK_PC command the
1060 * caller should check the request's errors value
1062 scsi_io_completion(cmd, cmd->request_bufflen);
1065 static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1067 struct scsi_cmnd *cmd;
1069 cmd = scsi_get_cmd_from_req(sdev, req);
1071 return BLKPREP_DEFER;
1074 * BLOCK_PC requests may transfer data, in which case they must
1075 * a bio attached to them. Or they might contain a SCSI command
1076 * that does not transfer data, in which case they may optionally
1077 * submit a request without an attached bio.
1082 BUG_ON(!req->nr_phys_segments);
1084 ret = scsi_init_io(cmd);
1088 BUG_ON(req->data_len);
1091 cmd->request_bufflen = 0;
1092 cmd->request_buffer = NULL;
1097 BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
1098 memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
1099 cmd->cmd_len = req->cmd_len;
1101 cmd->sc_data_direction = DMA_NONE;
1102 else if (rq_data_dir(req) == WRITE)
1103 cmd->sc_data_direction = DMA_TO_DEVICE;
1105 cmd->sc_data_direction = DMA_FROM_DEVICE;
1107 cmd->transfersize = req->data_len;
1108 cmd->allowed = req->retries;
1109 cmd->timeout_per_command = req->timeout;
1110 cmd->done = scsi_blk_pc_done;
1115 * Setup a REQ_TYPE_FS command. These are simple read/write request
1116 * from filesystems that still need to be translated to SCSI CDBs from
1119 static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1121 struct scsi_cmnd *cmd;
1122 struct scsi_driver *drv;
1126 * Filesystem requests must transfer data.
1128 BUG_ON(!req->nr_phys_segments);
1130 cmd = scsi_get_cmd_from_req(sdev, req);
1132 return BLKPREP_DEFER;
1134 ret = scsi_init_io(cmd);
1139 * Initialize the actual SCSI command for this request.
1141 drv = *(struct scsi_driver **)req->rq_disk->private_data;
1142 if (unlikely(!drv->init_command(cmd))) {
1143 scsi_release_buffers(cmd);
1144 scsi_put_command(cmd);
1145 return BLKPREP_KILL;
1151 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1153 struct scsi_device *sdev = q->queuedata;
1154 int ret = BLKPREP_OK;
1157 * If the device is not in running state we will reject some
1160 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1161 switch (sdev->sdev_state) {
1164 * If the device is offline we refuse to process any
1165 * commands. The device must be brought online
1166 * before trying any recovery commands.
1168 sdev_printk(KERN_ERR, sdev,
1169 "rejecting I/O to offline device\n");
1174 * If the device is fully deleted, we refuse to
1175 * process any commands as well.
1177 sdev_printk(KERN_ERR, sdev,
1178 "rejecting I/O to dead device\n");
1184 * If the devices is blocked we defer normal commands.
1186 if (!(req->cmd_flags & REQ_PREEMPT))
1187 ret = BLKPREP_DEFER;
1191 * For any other not fully online state we only allow
1192 * special commands. In particular any user initiated
1193 * command is not allowed.
1195 if (!(req->cmd_flags & REQ_PREEMPT))
1200 if (ret != BLKPREP_OK)
1204 switch (req->cmd_type) {
1205 case REQ_TYPE_BLOCK_PC:
1206 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1209 ret = scsi_setup_fs_cmnd(sdev, req);
1213 * All other command types are not supported.
1215 * Note that these days the SCSI subsystem does not use
1216 * REQ_TYPE_SPECIAL requests anymore. These are only used
1217 * (directly or via blk_insert_request) by non-SCSI drivers.
1219 blk_dump_rq_flags(req, "SCSI bad req");
1227 req->errors = DID_NO_CONNECT << 16;
1231 * If we defer, the elv_next_request() returns NULL, but the
1232 * queue must be restarted, so we plug here if no returning
1233 * command will automatically do that.
1235 if (sdev->device_busy == 0)
1239 req->cmd_flags |= REQ_DONTPREP;
1246 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1249 * Called with the queue_lock held.
1251 static inline int scsi_dev_queue_ready(struct request_queue *q,
1252 struct scsi_device *sdev)
1254 if (sdev->device_busy >= sdev->queue_depth)
1256 if (sdev->device_busy == 0 && sdev->device_blocked) {
1258 * unblock after device_blocked iterates to zero
1260 if (--sdev->device_blocked == 0) {
1262 sdev_printk(KERN_INFO, sdev,
1263 "unblocking device at zero depth\n"));
1269 if (sdev->device_blocked)
1276 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1277 * return 0. We must end up running the queue again whenever 0 is
1278 * returned, else IO can hang.
1280 * Called with host_lock held.
1282 static inline int scsi_host_queue_ready(struct request_queue *q,
1283 struct Scsi_Host *shost,
1284 struct scsi_device *sdev)
1286 if (scsi_host_in_recovery(shost))
1288 if (shost->host_busy == 0 && shost->host_blocked) {
1290 * unblock after host_blocked iterates to zero
1292 if (--shost->host_blocked == 0) {
1294 printk("scsi%d unblocking host at zero depth\n",
1301 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
1302 shost->host_blocked || shost->host_self_blocked) {
1303 if (list_empty(&sdev->starved_entry))
1304 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1308 /* We're OK to process the command, so we can't be starved */
1309 if (!list_empty(&sdev->starved_entry))
1310 list_del_init(&sdev->starved_entry);
1316 * Kill a request for a dead device
1318 static void scsi_kill_request(struct request *req, struct request_queue *q)
1320 struct scsi_cmnd *cmd = req->special;
1321 struct scsi_device *sdev = cmd->device;
1322 struct Scsi_Host *shost = sdev->host;
1324 blkdev_dequeue_request(req);
1326 if (unlikely(cmd == NULL)) {
1327 printk(KERN_CRIT "impossible request in %s.\n",
1332 scsi_init_cmd_errh(cmd);
1333 cmd->result = DID_NO_CONNECT << 16;
1334 atomic_inc(&cmd->device->iorequest_cnt);
1337 * SCSI request completion path will do scsi_device_unbusy(),
1338 * bump busy counts. To bump the counters, we need to dance
1339 * with the locks as normal issue path does.
1341 sdev->device_busy++;
1342 spin_unlock(sdev->request_queue->queue_lock);
1343 spin_lock(shost->host_lock);
1345 spin_unlock(shost->host_lock);
1346 spin_lock(sdev->request_queue->queue_lock);
1351 static void scsi_softirq_done(struct request *rq)
1353 struct scsi_cmnd *cmd = rq->completion_data;
1354 unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
1357 INIT_LIST_HEAD(&cmd->eh_entry);
1359 disposition = scsi_decide_disposition(cmd);
1360 if (disposition != SUCCESS &&
1361 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1362 sdev_printk(KERN_ERR, cmd->device,
1363 "timing out command, waited %lus\n",
1365 disposition = SUCCESS;
1368 scsi_log_completion(cmd, disposition);
1370 switch (disposition) {
1372 scsi_finish_command(cmd);
1375 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1377 case ADD_TO_MLQUEUE:
1378 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1381 if (!scsi_eh_scmd_add(cmd, 0))
1382 scsi_finish_command(cmd);
1387 * Function: scsi_request_fn()
1389 * Purpose: Main strategy routine for SCSI.
1391 * Arguments: q - Pointer to actual queue.
1395 * Lock status: IO request lock assumed to be held when called.
1397 static void scsi_request_fn(struct request_queue *q)
1399 struct scsi_device *sdev = q->queuedata;
1400 struct Scsi_Host *shost;
1401 struct scsi_cmnd *cmd;
1402 struct request *req;
1405 printk("scsi: killing requests for dead queue\n");
1406 while ((req = elv_next_request(q)) != NULL)
1407 scsi_kill_request(req, q);
1411 if(!get_device(&sdev->sdev_gendev))
1412 /* We must be tearing the block queue down already */
1416 * To start with, we keep looping until the queue is empty, or until
1417 * the host is no longer able to accept any more requests.
1420 while (!blk_queue_plugged(q)) {
1423 * get next queueable request. We do this early to make sure
1424 * that the request is fully prepared even if we cannot
1427 req = elv_next_request(q);
1428 if (!req || !scsi_dev_queue_ready(q, sdev))
1431 if (unlikely(!scsi_device_online(sdev))) {
1432 sdev_printk(KERN_ERR, sdev,
1433 "rejecting I/O to offline device\n");
1434 scsi_kill_request(req, q);
1440 * Remove the request from the request list.
1442 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1443 blkdev_dequeue_request(req);
1444 sdev->device_busy++;
1446 spin_unlock(q->queue_lock);
1448 if (unlikely(cmd == NULL)) {
1449 printk(KERN_CRIT "impossible request in %s.\n"
1450 "please mail a stack trace to "
1451 "linux-scsi@vger.kernel.org\n",
1453 blk_dump_rq_flags(req, "foo");
1456 spin_lock(shost->host_lock);
1458 if (!scsi_host_queue_ready(q, shost, sdev))
1460 if (sdev->single_lun) {
1461 if (scsi_target(sdev)->starget_sdev_user &&
1462 scsi_target(sdev)->starget_sdev_user != sdev)
1464 scsi_target(sdev)->starget_sdev_user = sdev;
1469 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1470 * take the lock again.
1472 spin_unlock_irq(shost->host_lock);
1475 * Finally, initialize any error handling parameters, and set up
1476 * the timers for timeouts.
1478 scsi_init_cmd_errh(cmd);
1481 * Dispatch the command to the low-level driver.
1483 rtn = scsi_dispatch_cmd(cmd);
1484 spin_lock_irq(q->queue_lock);
1486 /* we're refusing the command; because of
1487 * the way locks get dropped, we need to
1488 * check here if plugging is required */
1489 if(sdev->device_busy == 0)
1499 spin_unlock_irq(shost->host_lock);
1502 * lock q, handle tag, requeue req, and decrement device_busy. We
1503 * must return with queue_lock held.
1505 * Decrementing device_busy without checking it is OK, as all such
1506 * cases (host limits or settings) should run the queue at some
1509 spin_lock_irq(q->queue_lock);
1510 blk_requeue_request(q, req);
1511 sdev->device_busy--;
1512 if(sdev->device_busy == 0)
1515 /* must be careful here...if we trigger the ->remove() function
1516 * we cannot be holding the q lock */
1517 spin_unlock_irq(q->queue_lock);
1518 put_device(&sdev->sdev_gendev);
1519 spin_lock_irq(q->queue_lock);
1522 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1524 struct device *host_dev;
1525 u64 bounce_limit = 0xffffffff;
1527 if (shost->unchecked_isa_dma)
1528 return BLK_BOUNCE_ISA;
1530 * Platforms with virtual-DMA translation
1531 * hardware have no practical limit.
1533 if (!PCI_DMA_BUS_IS_PHYS)
1534 return BLK_BOUNCE_ANY;
1536 host_dev = scsi_get_device(shost);
1537 if (host_dev && host_dev->dma_mask)
1538 bounce_limit = *host_dev->dma_mask;
1540 return bounce_limit;
1542 EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1544 struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1545 request_fn_proc *request_fn)
1547 struct request_queue *q;
1549 q = blk_init_queue(request_fn, NULL);
1553 blk_queue_max_hw_segments(q, shost->sg_tablesize);
1554 blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS);
1555 blk_queue_max_sectors(q, shost->max_sectors);
1556 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1557 blk_queue_segment_boundary(q, shost->dma_boundary);
1559 if (!shost->use_clustering)
1560 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
1563 EXPORT_SYMBOL(__scsi_alloc_queue);
1565 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1567 struct request_queue *q;
1569 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1573 blk_queue_prep_rq(q, scsi_prep_fn);
1574 blk_queue_softirq_done(q, scsi_softirq_done);
1578 void scsi_free_queue(struct request_queue *q)
1580 blk_cleanup_queue(q);
1584 * Function: scsi_block_requests()
1586 * Purpose: Utility function used by low-level drivers to prevent further
1587 * commands from being queued to the device.
1589 * Arguments: shost - Host in question
1593 * Lock status: No locks are assumed held.
1595 * Notes: There is no timer nor any other means by which the requests
1596 * get unblocked other than the low-level driver calling
1597 * scsi_unblock_requests().
1599 void scsi_block_requests(struct Scsi_Host *shost)
1601 shost->host_self_blocked = 1;
1603 EXPORT_SYMBOL(scsi_block_requests);
1606 * Function: scsi_unblock_requests()
1608 * Purpose: Utility function used by low-level drivers to allow further
1609 * commands from being queued to the device.
1611 * Arguments: shost - Host in question
1615 * Lock status: No locks are assumed held.
1617 * Notes: There is no timer nor any other means by which the requests
1618 * get unblocked other than the low-level driver calling
1619 * scsi_unblock_requests().
1621 * This is done as an API function so that changes to the
1622 * internals of the scsi mid-layer won't require wholesale
1623 * changes to drivers that use this feature.
1625 void scsi_unblock_requests(struct Scsi_Host *shost)
1627 shost->host_self_blocked = 0;
1628 scsi_run_host_queues(shost);
1630 EXPORT_SYMBOL(scsi_unblock_requests);
1632 int __init scsi_init_queue(void)
1636 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1637 sizeof(struct scsi_io_context),
1639 if (!scsi_io_context_cache) {
1640 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1644 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1645 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1646 int size = sgp->size * sizeof(struct scatterlist);
1648 sgp->slab = kmem_cache_create(sgp->name, size, 0,
1649 SLAB_HWCACHE_ALIGN, NULL);
1651 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1655 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1658 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1666 void scsi_exit_queue(void)
1670 kmem_cache_destroy(scsi_io_context_cache);
1672 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1673 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1674 mempool_destroy(sgp->pool);
1675 kmem_cache_destroy(sgp->slab);
1680 * scsi_mode_select - issue a mode select
1681 * @sdev: SCSI device to be queried
1682 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1683 * @sp: Save page bit (0 == don't save, 1 == save)
1684 * @modepage: mode page being requested
1685 * @buffer: request buffer (may not be smaller than eight bytes)
1686 * @len: length of request buffer.
1687 * @timeout: command timeout
1688 * @retries: number of retries before failing
1689 * @data: returns a structure abstracting the mode header data
1690 * @sense: place to put sense data (or NULL if no sense to be collected).
1691 * must be SCSI_SENSE_BUFFERSIZE big.
1693 * Returns zero if successful; negative error number or scsi
1698 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1699 unsigned char *buffer, int len, int timeout, int retries,
1700 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1702 unsigned char cmd[10];
1703 unsigned char *real_buffer;
1706 memset(cmd, 0, sizeof(cmd));
1707 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1709 if (sdev->use_10_for_ms) {
1712 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1715 memcpy(real_buffer + 8, buffer, len);
1719 real_buffer[2] = data->medium_type;
1720 real_buffer[3] = data->device_specific;
1721 real_buffer[4] = data->longlba ? 0x01 : 0;
1723 real_buffer[6] = data->block_descriptor_length >> 8;
1724 real_buffer[7] = data->block_descriptor_length;
1726 cmd[0] = MODE_SELECT_10;
1730 if (len > 255 || data->block_descriptor_length > 255 ||
1734 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1737 memcpy(real_buffer + 4, buffer, len);
1740 real_buffer[1] = data->medium_type;
1741 real_buffer[2] = data->device_specific;
1742 real_buffer[3] = data->block_descriptor_length;
1745 cmd[0] = MODE_SELECT;
1749 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1750 sshdr, timeout, retries);
1754 EXPORT_SYMBOL_GPL(scsi_mode_select);
1757 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1758 * six bytes if necessary.
1759 * @sdev: SCSI device to be queried
1760 * @dbd: set if mode sense will allow block descriptors to be returned
1761 * @modepage: mode page being requested
1762 * @buffer: request buffer (may not be smaller than eight bytes)
1763 * @len: length of request buffer.
1764 * @timeout: command timeout
1765 * @retries: number of retries before failing
1766 * @data: returns a structure abstracting the mode header data
1767 * @sense: place to put sense data (or NULL if no sense to be collected).
1768 * must be SCSI_SENSE_BUFFERSIZE big.
1770 * Returns zero if unsuccessful, or the header offset (either 4
1771 * or 8 depending on whether a six or ten byte command was
1772 * issued) if successful.
1775 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
1776 unsigned char *buffer, int len, int timeout, int retries,
1777 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1779 unsigned char cmd[12];
1783 struct scsi_sense_hdr my_sshdr;
1785 memset(data, 0, sizeof(*data));
1786 memset(&cmd[0], 0, 12);
1787 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1790 /* caller might not be interested in sense, but we need it */
1795 use_10_for_ms = sdev->use_10_for_ms;
1797 if (use_10_for_ms) {
1801 cmd[0] = MODE_SENSE_10;
1808 cmd[0] = MODE_SENSE;
1813 memset(buffer, 0, len);
1815 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1816 sshdr, timeout, retries);
1818 /* This code looks awful: what it's doing is making sure an
1819 * ILLEGAL REQUEST sense return identifies the actual command
1820 * byte as the problem. MODE_SENSE commands can return
1821 * ILLEGAL REQUEST if the code page isn't supported */
1823 if (use_10_for_ms && !scsi_status_is_good(result) &&
1824 (driver_byte(result) & DRIVER_SENSE)) {
1825 if (scsi_sense_valid(sshdr)) {
1826 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1827 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
1829 * Invalid command operation code
1831 sdev->use_10_for_ms = 0;
1837 if(scsi_status_is_good(result)) {
1838 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1839 (modepage == 6 || modepage == 8))) {
1840 /* Initio breakage? */
1843 data->medium_type = 0;
1844 data->device_specific = 0;
1846 data->block_descriptor_length = 0;
1847 } else if(use_10_for_ms) {
1848 data->length = buffer[0]*256 + buffer[1] + 2;
1849 data->medium_type = buffer[2];
1850 data->device_specific = buffer[3];
1851 data->longlba = buffer[4] & 0x01;
1852 data->block_descriptor_length = buffer[6]*256
1855 data->length = buffer[0] + 1;
1856 data->medium_type = buffer[1];
1857 data->device_specific = buffer[2];
1858 data->block_descriptor_length = buffer[3];
1860 data->header_length = header_length;
1865 EXPORT_SYMBOL(scsi_mode_sense);
1868 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries)
1871 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1873 struct scsi_sense_hdr sshdr;
1876 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr,
1879 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
1881 if ((scsi_sense_valid(&sshdr)) &&
1882 ((sshdr.sense_key == UNIT_ATTENTION) ||
1883 (sshdr.sense_key == NOT_READY))) {
1890 EXPORT_SYMBOL(scsi_test_unit_ready);
1893 * scsi_device_set_state - Take the given device through the device
1895 * @sdev: scsi device to change the state of.
1896 * @state: state to change to.
1898 * Returns zero if unsuccessful or an error if the requested
1899 * transition is illegal.
1902 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
1904 enum scsi_device_state oldstate = sdev->sdev_state;
1906 if (state == oldstate)
1911 /* There are no legal states that come back to
1912 * created. This is the manually initialised start
1986 sdev->sdev_state = state;
1990 SCSI_LOG_ERROR_RECOVERY(1,
1991 sdev_printk(KERN_ERR, sdev,
1992 "Illegal state transition %s->%s\n",
1993 scsi_device_state_name(oldstate),
1994 scsi_device_state_name(state))
1998 EXPORT_SYMBOL(scsi_device_set_state);
2001 * scsi_device_quiesce - Block user issued commands.
2002 * @sdev: scsi device to quiesce.
2004 * This works by trying to transition to the SDEV_QUIESCE state
2005 * (which must be a legal transition). When the device is in this
2006 * state, only special requests will be accepted, all others will
2007 * be deferred. Since special requests may also be requeued requests,
2008 * a successful return doesn't guarantee the device will be
2009 * totally quiescent.
2011 * Must be called with user context, may sleep.
2013 * Returns zero if unsuccessful or an error if not.
2016 scsi_device_quiesce(struct scsi_device *sdev)
2018 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2022 scsi_run_queue(sdev->request_queue);
2023 while (sdev->device_busy) {
2024 msleep_interruptible(200);
2025 scsi_run_queue(sdev->request_queue);
2029 EXPORT_SYMBOL(scsi_device_quiesce);
2032 * scsi_device_resume - Restart user issued commands to a quiesced device.
2033 * @sdev: scsi device to resume.
2035 * Moves the device from quiesced back to running and restarts the
2038 * Must be called with user context, may sleep.
2041 scsi_device_resume(struct scsi_device *sdev)
2043 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2045 scsi_run_queue(sdev->request_queue);
2047 EXPORT_SYMBOL(scsi_device_resume);
2050 device_quiesce_fn(struct scsi_device *sdev, void *data)
2052 scsi_device_quiesce(sdev);
2056 scsi_target_quiesce(struct scsi_target *starget)
2058 starget_for_each_device(starget, NULL, device_quiesce_fn);
2060 EXPORT_SYMBOL(scsi_target_quiesce);
2063 device_resume_fn(struct scsi_device *sdev, void *data)
2065 scsi_device_resume(sdev);
2069 scsi_target_resume(struct scsi_target *starget)
2071 starget_for_each_device(starget, NULL, device_resume_fn);
2073 EXPORT_SYMBOL(scsi_target_resume);
2076 * scsi_internal_device_block - internal function to put a device
2077 * temporarily into the SDEV_BLOCK state
2078 * @sdev: device to block
2080 * Block request made by scsi lld's to temporarily stop all
2081 * scsi commands on the specified device. Called from interrupt
2082 * or normal process context.
2084 * Returns zero if successful or error if not
2087 * This routine transitions the device to the SDEV_BLOCK state
2088 * (which must be a legal transition). When the device is in this
2089 * state, all commands are deferred until the scsi lld reenables
2090 * the device with scsi_device_unblock or device_block_tmo fires.
2091 * This routine assumes the host_lock is held on entry.
2094 scsi_internal_device_block(struct scsi_device *sdev)
2096 struct request_queue *q = sdev->request_queue;
2097 unsigned long flags;
2100 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2105 * The device has transitioned to SDEV_BLOCK. Stop the
2106 * block layer from calling the midlayer with this device's
2109 spin_lock_irqsave(q->queue_lock, flags);
2111 spin_unlock_irqrestore(q->queue_lock, flags);
2115 EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2118 * scsi_internal_device_unblock - resume a device after a block request
2119 * @sdev: device to resume
2121 * Called by scsi lld's or the midlayer to restart the device queue
2122 * for the previously suspended scsi device. Called from interrupt or
2123 * normal process context.
2125 * Returns zero if successful or error if not.
2128 * This routine transitions the device to the SDEV_RUNNING state
2129 * (which must be a legal transition) allowing the midlayer to
2130 * goose the queue for this device. This routine assumes the
2131 * host_lock is held upon entry.
2134 scsi_internal_device_unblock(struct scsi_device *sdev)
2136 struct request_queue *q = sdev->request_queue;
2138 unsigned long flags;
2141 * Try to transition the scsi device to SDEV_RUNNING
2142 * and goose the device queue if successful.
2144 err = scsi_device_set_state(sdev, SDEV_RUNNING);
2148 spin_lock_irqsave(q->queue_lock, flags);
2150 spin_unlock_irqrestore(q->queue_lock, flags);
2154 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2157 device_block(struct scsi_device *sdev, void *data)
2159 scsi_internal_device_block(sdev);
2163 target_block(struct device *dev, void *data)
2165 if (scsi_is_target_device(dev))
2166 starget_for_each_device(to_scsi_target(dev), NULL,
2172 scsi_target_block(struct device *dev)
2174 if (scsi_is_target_device(dev))
2175 starget_for_each_device(to_scsi_target(dev), NULL,
2178 device_for_each_child(dev, NULL, target_block);
2180 EXPORT_SYMBOL_GPL(scsi_target_block);
2183 device_unblock(struct scsi_device *sdev, void *data)
2185 scsi_internal_device_unblock(sdev);
2189 target_unblock(struct device *dev, void *data)
2191 if (scsi_is_target_device(dev))
2192 starget_for_each_device(to_scsi_target(dev), NULL,
2198 scsi_target_unblock(struct device *dev)
2200 if (scsi_is_target_device(dev))
2201 starget_for_each_device(to_scsi_target(dev), NULL,
2204 device_for_each_child(dev, NULL, target_unblock);
2206 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2209 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2210 * @sg: scatter-gather list
2211 * @sg_count: number of segments in sg
2212 * @offset: offset in bytes into sg, on return offset into the mapped area
2213 * @len: bytes to map, on return number of bytes mapped
2215 * Returns virtual address of the start of the mapped page
2217 void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
2218 size_t *offset, size_t *len)
2221 size_t sg_len = 0, len_complete = 0;
2224 WARN_ON(!irqs_disabled());
2226 for (i = 0; i < sg_count; i++) {
2227 len_complete = sg_len; /* Complete sg-entries */
2228 sg_len += sg[i].length;
2229 if (sg_len > *offset)
2233 if (unlikely(i == sg_count)) {
2234 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2236 __FUNCTION__, sg_len, *offset, sg_count);
2241 /* Offset starting from the beginning of first page in this sg-entry */
2242 *offset = *offset - len_complete + sg[i].offset;
2244 /* Assumption: contiguous pages can be accessed as "page + i" */
2245 page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));
2246 *offset &= ~PAGE_MASK;
2248 /* Bytes in this sg-entry from *offset to the end of the page */
2249 sg_len = PAGE_SIZE - *offset;
2253 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2255 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2258 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2259 * mapped with scsi_kmap_atomic_sg
2260 * @virt: virtual address to be unmapped
2262 void scsi_kunmap_atomic_sg(void *virt)
2264 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2266 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);