2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
12 * Bug correction thanks go to :
13 * Rik Faith <faith@cs.unc.edu>
14 * Tommy Thorn <tthorn>
15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 * add scatter-gather, multiple outstanding request, and other
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
24 * Added request_module("scsi_hostadapter") for kerneld:
25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 * Bjorn Ekwall <bj0rn@blox.se>
29 * Major improvements to the timeout, abort, and reset processing,
30 * as well as performance modifications for large queue depths by
31 * Leonard N. Zubkoff <lnz@dandelion.com>
33 * Converted cli() code to spinlocks, Ingo Molnar
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 * out_of_space hacks, D. Gilbert (dpg) 990608
40 #include <linux/module.h>
41 #include <linux/moduleparam.h>
42 #include <linux/kernel.h>
43 #include <linux/timer.h>
44 #include <linux/string.h>
45 #include <linux/slab.h>
46 #include <linux/blkdev.h>
47 #include <linux/delay.h>
48 #include <linux/init.h>
49 #include <linux/completion.h>
50 #include <linux/unistd.h>
51 #include <linux/spinlock.h>
52 #include <linux/kmod.h>
53 #include <linux/interrupt.h>
54 #include <linux/notifier.h>
55 #include <linux/cpu.h>
56 #include <linux/mutex.h>
57 #include <linux/async.h>
58 #include <asm/unaligned.h>
60 #include <scsi/scsi.h>
61 #include <scsi/scsi_cmnd.h>
62 #include <scsi/scsi_dbg.h>
63 #include <scsi/scsi_device.h>
64 #include <scsi/scsi_driver.h>
65 #include <scsi/scsi_eh.h>
66 #include <scsi/scsi_host.h>
67 #include <scsi/scsi_tcq.h>
69 #include "scsi_priv.h"
70 #include "scsi_logging.h"
72 #define CREATE_TRACE_POINTS
73 #include <trace/events/scsi.h>
76 * Definitions and constants.
80 * Note - the initial logging level can be set here to log events at boot time.
81 * After the system is up, you may enable logging via the /proc interface.
83 unsigned int scsi_logging_level;
84 #if defined(CONFIG_SCSI_LOGGING)
85 EXPORT_SYMBOL(scsi_logging_level);
88 /* sd, scsi core and power management need to coordinate flushing async actions */
89 ASYNC_DOMAIN(scsi_sd_probe_domain);
90 EXPORT_SYMBOL(scsi_sd_probe_domain);
93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
94 * asynchronous system resume operations. It is marked 'exclusive' to avoid
95 * being included in the async_synchronize_full() that is invoked by
98 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
99 EXPORT_SYMBOL(scsi_sd_pm_domain);
101 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
102 * You may not alter any existing entry (although adding new ones is
103 * encouraged once assigned by ANSI/INCITS T10
105 static const char *const scsi_device_types[] = {
130 * scsi_device_type - Return 17 char string indicating device type.
131 * @type: type number to look up
134 const char * scsi_device_type(unsigned type)
137 return "Well-known LUN ";
140 if (type >= ARRAY_SIZE(scsi_device_types))
142 return scsi_device_types[type];
145 EXPORT_SYMBOL(scsi_device_type);
147 struct scsi_host_cmd_pool {
148 struct kmem_cache *cmd_slab;
149 struct kmem_cache *sense_slab;
153 unsigned int slab_flags;
157 static struct scsi_host_cmd_pool scsi_cmd_pool = {
158 .cmd_name = "scsi_cmd_cache",
159 .sense_name = "scsi_sense_cache",
160 .slab_flags = SLAB_HWCACHE_ALIGN,
163 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
164 .cmd_name = "scsi_cmd_cache(DMA)",
165 .sense_name = "scsi_sense_cache(DMA)",
166 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
167 .gfp_mask = __GFP_DMA,
170 static DEFINE_MUTEX(host_cmd_pool_mutex);
173 * scsi_host_free_command - internal function to release a command
174 * @shost: host to free the command for
175 * @cmd: command to release
177 * the command must previously have been allocated by
178 * scsi_host_alloc_command.
181 scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
183 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
186 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
187 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
188 kmem_cache_free(pool->cmd_slab, cmd);
192 * scsi_host_alloc_command - internal function to allocate command
193 * @shost: SCSI host whose pool to allocate from
194 * @gfp_mask: mask for the allocation
196 * Returns a fully allocated command with sense buffer and protection
197 * data buffer (where applicable) or NULL on failure
199 static struct scsi_cmnd *
200 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
202 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
203 struct scsi_cmnd *cmd;
205 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
209 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
210 gfp_mask | pool->gfp_mask);
211 if (!cmd->sense_buffer)
214 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
215 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
217 goto fail_free_sense;
223 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
225 kmem_cache_free(pool->cmd_slab, cmd);
231 * __scsi_get_command - Allocate a struct scsi_cmnd
232 * @shost: host to transmit command
233 * @gfp_mask: allocation mask
235 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
236 * host's free_list if necessary.
238 static struct scsi_cmnd *
239 __scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
241 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
243 if (unlikely(!cmd)) {
246 spin_lock_irqsave(&shost->free_list_lock, flags);
247 if (likely(!list_empty(&shost->free_list))) {
248 cmd = list_entry(shost->free_list.next,
249 struct scsi_cmnd, list);
250 list_del_init(&cmd->list);
252 spin_unlock_irqrestore(&shost->free_list_lock, flags);
257 buf = cmd->sense_buffer;
258 prot = cmd->prot_sdb;
260 memset(cmd, 0, sizeof(*cmd));
262 cmd->sense_buffer = buf;
263 cmd->prot_sdb = prot;
271 * scsi_get_command - Allocate and setup a scsi command block
272 * @dev: parent scsi device
273 * @gfp_mask: allocator flags
275 * Returns: The allocated scsi command structure.
277 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
279 struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
282 if (unlikely(cmd == NULL))
286 INIT_LIST_HEAD(&cmd->list);
287 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
288 spin_lock_irqsave(&dev->list_lock, flags);
289 list_add_tail(&cmd->list, &dev->cmd_list);
290 spin_unlock_irqrestore(&dev->list_lock, flags);
291 cmd->jiffies_at_alloc = jiffies;
296 * __scsi_put_command - Free a struct scsi_cmnd
298 * @cmd: Command to free
300 static void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
304 if (unlikely(list_empty(&shost->free_list))) {
305 spin_lock_irqsave(&shost->free_list_lock, flags);
306 if (list_empty(&shost->free_list)) {
307 list_add(&cmd->list, &shost->free_list);
310 spin_unlock_irqrestore(&shost->free_list_lock, flags);
313 if (likely(cmd != NULL))
314 scsi_host_free_command(shost, cmd);
318 * scsi_put_command - Free a scsi command block
319 * @cmd: command block to free
323 * Notes: The command must not belong to any lists.
325 void scsi_put_command(struct scsi_cmnd *cmd)
329 /* serious error if the command hasn't come from a device list */
330 spin_lock_irqsave(&cmd->device->list_lock, flags);
331 BUG_ON(list_empty(&cmd->list));
332 list_del_init(&cmd->list);
333 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
335 BUG_ON(delayed_work_pending(&cmd->abort_work));
337 __scsi_put_command(cmd->device->host, cmd);
340 static struct scsi_host_cmd_pool *
341 scsi_find_host_cmd_pool(struct Scsi_Host *shost)
343 if (shost->hostt->cmd_size)
344 return shost->hostt->cmd_pool;
345 if (shost->unchecked_isa_dma)
346 return &scsi_cmd_dma_pool;
347 return &scsi_cmd_pool;
351 scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
353 kfree(pool->sense_name);
354 kfree(pool->cmd_name);
358 static struct scsi_host_cmd_pool *
359 scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
361 struct scsi_host_template *hostt = shost->hostt;
362 struct scsi_host_cmd_pool *pool;
364 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
368 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->proc_name);
369 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->proc_name);
370 if (!pool->cmd_name || !pool->sense_name) {
371 scsi_free_host_cmd_pool(pool);
375 pool->slab_flags = SLAB_HWCACHE_ALIGN;
376 if (shost->unchecked_isa_dma) {
377 pool->slab_flags |= SLAB_CACHE_DMA;
378 pool->gfp_mask = __GFP_DMA;
382 hostt->cmd_pool = pool;
387 static struct scsi_host_cmd_pool *
388 scsi_get_host_cmd_pool(struct Scsi_Host *shost)
390 struct scsi_host_template *hostt = shost->hostt;
391 struct scsi_host_cmd_pool *retval = NULL, *pool;
392 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
395 * Select a command slab for this host and create it if not
398 mutex_lock(&host_cmd_pool_mutex);
399 pool = scsi_find_host_cmd_pool(shost);
401 pool = scsi_alloc_host_cmd_pool(shost);
407 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
408 pool->slab_flags, NULL);
412 pool->sense_slab = kmem_cache_create(pool->sense_name,
413 SCSI_SENSE_BUFFERSIZE, 0,
414 pool->slab_flags, NULL);
415 if (!pool->sense_slab)
422 mutex_unlock(&host_cmd_pool_mutex);
426 kmem_cache_destroy(pool->cmd_slab);
428 if (hostt->cmd_size) {
429 scsi_free_host_cmd_pool(pool);
430 hostt->cmd_pool = NULL;
435 static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
437 struct scsi_host_template *hostt = shost->hostt;
438 struct scsi_host_cmd_pool *pool;
440 mutex_lock(&host_cmd_pool_mutex);
441 pool = scsi_find_host_cmd_pool(shost);
444 * This may happen if a driver has a mismatched get and put
445 * of the command pool; the driver should be implicated in
448 BUG_ON(pool->users == 0);
450 if (!--pool->users) {
451 kmem_cache_destroy(pool->cmd_slab);
452 kmem_cache_destroy(pool->sense_slab);
453 if (hostt->cmd_size) {
454 scsi_free_host_cmd_pool(pool);
455 hostt->cmd_pool = NULL;
458 mutex_unlock(&host_cmd_pool_mutex);
462 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
463 * @shost: host to allocate the freelist for.
465 * Description: The command freelist protects against system-wide out of memory
466 * deadlock by preallocating one SCSI command structure for each host, so the
467 * system can always write to a swap file on a device associated with that host.
471 int scsi_setup_command_freelist(struct Scsi_Host *shost)
473 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
474 struct scsi_cmnd *cmd;
476 spin_lock_init(&shost->free_list_lock);
477 INIT_LIST_HEAD(&shost->free_list);
479 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
480 if (!shost->cmd_pool)
484 * Get one backup command for this host.
486 cmd = scsi_host_alloc_command(shost, gfp_mask);
488 scsi_put_host_cmd_pool(shost);
489 shost->cmd_pool = NULL;
492 list_add(&cmd->list, &shost->free_list);
497 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
498 * @shost: host whose freelist is going to be destroyed
500 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
503 * If cmd_pool is NULL the free list was not initialized, so
504 * do not attempt to release resources.
506 if (!shost->cmd_pool)
509 while (!list_empty(&shost->free_list)) {
510 struct scsi_cmnd *cmd;
512 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
513 list_del_init(&cmd->list);
514 scsi_host_free_command(shost, cmd);
516 shost->cmd_pool = NULL;
517 scsi_put_host_cmd_pool(shost);
520 #ifdef CONFIG_SCSI_LOGGING
521 void scsi_log_send(struct scsi_cmnd *cmd)
526 * If ML QUEUE log level is greater than or equal to:
528 * 1: nothing (match completion)
530 * 2: log opcode + command of all commands
532 * 3: same as 2 plus dump cmd address
534 * 4: same as 3 plus dump extra junk
536 if (unlikely(scsi_logging_level)) {
537 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
538 SCSI_LOG_MLQUEUE_BITS);
540 scmd_printk(KERN_INFO, cmd, "Send: ");
542 printk("0x%p ", cmd);
544 scsi_print_command(cmd);
546 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
547 " queuecommand 0x%p\n",
548 scsi_sglist(cmd), scsi_bufflen(cmd),
549 cmd->device->host->hostt->queuecommand);
556 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
561 * If ML COMPLETE log level is greater than or equal to:
563 * 1: log disposition, result, opcode + command, and conditionally
564 * sense data for failures or non SUCCESS dispositions.
566 * 2: same as 1 but for all command completions.
568 * 3: same as 2 plus dump cmd address
570 * 4: same as 3 plus dump extra junk
572 if (unlikely(scsi_logging_level)) {
573 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
574 SCSI_LOG_MLCOMPLETE_BITS);
575 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
577 scmd_printk(KERN_INFO, cmd, "Done: ");
579 printk("0x%p ", cmd);
581 * Dump truncated values, so we usually fit within
584 switch (disposition) {
599 * If called via scsi_times_out.
606 scsi_print_result(cmd);
607 scsi_print_command(cmd);
608 if (status_byte(cmd->result) & CHECK_CONDITION)
609 scsi_print_sense("", cmd);
611 scmd_printk(KERN_INFO, cmd,
612 "scsi host busy %d failed %d\n",
613 atomic_read(&cmd->device->host->host_busy),
614 cmd->device->host->host_failed);
621 * scsi_cmd_get_serial - Assign a serial number to a command
622 * @host: the scsi host
623 * @cmd: command to assign serial number to
625 * Description: a serial number identifies a request for error recovery
626 * and debugging purposes. Protected by the Host_Lock of host.
628 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
630 cmd->serial_number = host->cmd_serial_number++;
631 if (cmd->serial_number == 0)
632 cmd->serial_number = host->cmd_serial_number++;
634 EXPORT_SYMBOL(scsi_cmd_get_serial);
637 * scsi_dispatch_command - Dispatch a command to the low-level driver.
638 * @cmd: command block we are dispatching.
640 * Return: nonzero return request was rejected and device's queue needs to be
643 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
645 struct Scsi_Host *host = cmd->device->host;
648 atomic_inc(&cmd->device->iorequest_cnt);
650 /* check if the device is still usable */
651 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
652 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
653 * returns an immediate error upwards, and signals
654 * that the device is no longer present */
655 cmd->result = DID_NO_CONNECT << 16;
659 /* Check to see if the scsi lld made this device blocked. */
660 if (unlikely(scsi_device_blocked(cmd->device))) {
662 * in blocked state, the command is just put back on
663 * the device queue. The suspend state has already
664 * blocked the queue so future requests should not
665 * occur until the device transitions out of the
668 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
669 "queuecommand : device blocked\n"));
670 return SCSI_MLQUEUE_DEVICE_BUSY;
674 * If SCSI-2 or lower, store the LUN value in cmnd.
676 if (cmd->device->scsi_level <= SCSI_2 &&
677 cmd->device->scsi_level != SCSI_UNKNOWN) {
678 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
679 (cmd->device->lun << 5 & 0xe0);
685 * Before we queue this command, check if the command
686 * length exceeds what the host adapter can handle.
688 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
689 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
690 "queuecommand : command too long. "
691 "cdb_size=%d host->max_cmd_len=%d\n",
692 cmd->cmd_len, cmd->device->host->max_cmd_len));
693 cmd->result = (DID_ABORT << 16);
697 if (unlikely(host->shost_state == SHOST_DEL)) {
698 cmd->result = (DID_NO_CONNECT << 16);
703 trace_scsi_dispatch_cmd_start(cmd);
704 rtn = host->hostt->queuecommand(host, cmd);
706 trace_scsi_dispatch_cmd_error(cmd, rtn);
707 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
708 rtn != SCSI_MLQUEUE_TARGET_BUSY)
709 rtn = SCSI_MLQUEUE_HOST_BUSY;
711 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
712 "queuecommand : request rejected\n"));
722 * scsi_finish_command - cleanup and pass command back to upper layer
725 * Description: Pass command off to upper layer for finishing of I/O
726 * request, waking processes that are waiting on results,
729 void scsi_finish_command(struct scsi_cmnd *cmd)
731 struct scsi_device *sdev = cmd->device;
732 struct scsi_target *starget = scsi_target(sdev);
733 struct Scsi_Host *shost = sdev->host;
734 struct scsi_driver *drv;
735 unsigned int good_bytes;
737 scsi_device_unbusy(sdev);
740 * Clear the flags that say that the device/target/host is no longer
741 * capable of accepting new commands.
743 if (atomic_read(&shost->host_blocked))
744 atomic_set(&shost->host_blocked, 0);
745 if (atomic_read(&starget->target_blocked))
746 atomic_set(&starget->target_blocked, 0);
747 if (atomic_read(&sdev->device_blocked))
748 atomic_set(&sdev->device_blocked, 0);
751 * If we have valid sense information, then some kind of recovery
752 * must have taken place. Make a note of this.
754 if (SCSI_SENSE_VALID(cmd))
755 cmd->result |= (DRIVER_SENSE << 24);
757 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
758 "Notifying upper driver of completion "
759 "(result %x)\n", cmd->result));
761 good_bytes = scsi_bufflen(cmd);
762 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
763 int old_good_bytes = good_bytes;
764 drv = scsi_cmd_to_driver(cmd);
766 good_bytes = drv->done(cmd);
768 * USB may not give sense identifying bad sector and
769 * simply return a residue instead, so subtract off the
770 * residue if drv->done() error processing indicates no
771 * change to the completion length.
773 if (good_bytes == old_good_bytes)
774 good_bytes -= scsi_get_resid(cmd);
776 scsi_io_completion(cmd, good_bytes);
780 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
781 * @sdev: SCSI Device in question
782 * @tagged: Do we use tagged queueing (non-0) or do we treat
783 * this device as an untagged device (0)
784 * @tags: Number of tags allowed if tagged queueing enabled,
785 * or number of commands the low level driver can
786 * queue up in non-tagged mode (as per cmd_per_lun).
790 * Lock Status: None held on entry
792 * Notes: Low level drivers may call this at any time and we will do
793 * the right thing depending on whether or not the device is
794 * currently active and whether or not it even has the
795 * command blocks built yet.
797 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
802 * refuse to set tagged depth to an unworkable size
807 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
810 * Check to see if the queue is managed by the block layer.
811 * If it is, and we fail to adjust the depth, exit.
813 * Do not resize the tag map if it is a host wide share bqt,
814 * because the size should be the hosts's can_queue. If there
815 * is more IO than the LLD's can_queue (so there are not enuogh
816 * tags) request_fn's host queue ready check will handle it.
818 if (!shost_use_blk_mq(sdev->host) && !sdev->host->bqt) {
819 if (blk_queue_tagged(sdev->request_queue) &&
820 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
824 sdev->queue_depth = tags;
827 sdev->ordered_tags = 0;
828 sdev->simple_tags = 0;
830 case MSG_ORDERED_TAG:
831 sdev->ordered_tags = 1;
832 sdev->simple_tags = 1;
835 sdev->ordered_tags = 0;
836 sdev->simple_tags = 1;
839 sdev->ordered_tags = 0;
840 sdev->simple_tags = 0;
841 sdev_printk(KERN_WARNING, sdev,
842 "scsi_adjust_queue_depth, bad queue type, "
846 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
848 EXPORT_SYMBOL(scsi_adjust_queue_depth);
851 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
852 * @sdev: SCSI Device in question
853 * @depth: Current number of outstanding SCSI commands on this device,
854 * not counting the one returned as QUEUE_FULL.
856 * Description: This function will track successive QUEUE_FULL events on a
857 * specific SCSI device to determine if and when there is a
858 * need to adjust the queue depth on the device.
860 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
861 * -1 - Drop back to untagged operation using host->cmd_per_lun
862 * as the untagged command depth
864 * Lock Status: None held on entry
866 * Notes: Low level drivers may call this at any time and we will do
867 * "The Right Thing." We are interrupt context safe.
869 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
873 * Don't let QUEUE_FULLs on the same
874 * jiffies count, they could all be from
877 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
880 sdev->last_queue_full_time = jiffies;
881 if (sdev->last_queue_full_depth != depth) {
882 sdev->last_queue_full_count = 1;
883 sdev->last_queue_full_depth = depth;
885 sdev->last_queue_full_count++;
888 if (sdev->last_queue_full_count <= 10)
890 if (sdev->last_queue_full_depth < 8) {
891 /* Drop back to untagged */
892 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
896 if (sdev->ordered_tags)
897 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
899 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
902 EXPORT_SYMBOL(scsi_track_queue_full);
905 * scsi_vpd_inquiry - Request a device provide us with a VPD page
906 * @sdev: The device to ask
907 * @buffer: Where to put the result
908 * @page: Which Vital Product Data to return
909 * @len: The length of the buffer
911 * This is an internal helper function. You probably want to use
912 * scsi_get_vpd_page instead.
914 * Returns size of the vpd page on success or a negative error number.
916 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
917 u8 page, unsigned len)
920 unsigned char cmd[16];
926 cmd[1] = 1; /* EVPD */
930 cmd[5] = 0; /* Control byte */
933 * I'm not convinced we need to try quite this hard to get VPD, but
934 * all the existing users tried this hard.
936 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
937 len, NULL, 30 * HZ, 3, NULL);
941 /* Sanity check that we got the page back that we asked for */
942 if (buffer[1] != page)
945 return get_unaligned_be16(&buffer[2]) + 4;
949 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
950 * @sdev: The device to ask
951 * @page: Which Vital Product Data to return
952 * @buf: where to store the VPD
953 * @buf_len: number of bytes in the VPD buffer area
955 * SCSI devices may optionally supply Vital Product Data. Each 'page'
956 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
957 * If the device supports this VPD page, this routine returns a pointer
958 * to a buffer containing the data from that page. The caller is
959 * responsible for calling kfree() on this pointer when it is no longer
960 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
962 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
967 if (sdev->skip_vpd_pages)
970 /* Ask for all the pages supported by this device */
971 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
975 /* If the user actually wanted this page, we can skip the rest */
979 for (i = 4; i < min(result, buf_len); i++)
983 if (i < result && i >= buf_len)
984 /* ran off the end of the buffer, give us benefit of doubt */
986 /* The device claims it doesn't support the requested page */
990 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
999 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1002 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
1003 * @sdev: The device to ask
1005 * Attach the 'Device Identification' VPD page (0x83) and the
1006 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
1007 * structure. This information can be used to identify the device
1010 void scsi_attach_vpd(struct scsi_device *sdev)
1013 int vpd_len = SCSI_VPD_PG_LEN;
1014 int pg80_supported = 0;
1015 int pg83_supported = 0;
1016 unsigned char *vpd_buf;
1018 if (sdev->skip_vpd_pages)
1021 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1025 /* Ask for all the pages supported by this device */
1026 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
1031 if (result > vpd_len) {
1037 for (i = 4; i < result; i++) {
1038 if (vpd_buf[i] == 0x80)
1040 if (vpd_buf[i] == 0x83)
1044 vpd_len = SCSI_VPD_PG_LEN;
1046 if (pg80_supported) {
1048 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1052 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
1057 if (result > vpd_len) {
1062 sdev->vpd_pg80_len = result;
1063 sdev->vpd_pg80 = vpd_buf;
1064 vpd_len = SCSI_VPD_PG_LEN;
1067 if (pg83_supported) {
1069 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1073 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
1078 if (result > vpd_len) {
1083 sdev->vpd_pg83_len = result;
1084 sdev->vpd_pg83 = vpd_buf;
1089 * scsi_report_opcode - Find out if a given command opcode is supported
1090 * @sdev: scsi device to query
1091 * @buffer: scratch buffer (must be at least 20 bytes long)
1092 * @len: length of buffer
1093 * @opcode: opcode for command to look up
1095 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1096 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1097 * unsupported and 1 if the device claims to support the command.
1099 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1100 unsigned int len, unsigned char opcode)
1102 unsigned char cmd[16];
1103 struct scsi_sense_hdr sshdr;
1106 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1110 cmd[0] = MAINTENANCE_IN;
1111 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1112 cmd[2] = 1; /* One command format */
1114 put_unaligned_be32(len, &cmd[6]);
1115 memset(buffer, 0, len);
1117 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1118 &sshdr, 30 * HZ, 3, NULL);
1120 if (result && scsi_sense_valid(&sshdr) &&
1121 sshdr.sense_key == ILLEGAL_REQUEST &&
1122 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1125 if ((buffer[1] & 3) == 3) /* Command supported */
1130 EXPORT_SYMBOL(scsi_report_opcode);
1133 * scsi_device_get - get an additional reference to a scsi_device
1134 * @sdev: device to get a reference to
1136 * Description: Gets a reference to the scsi_device and increments the use count
1137 * of the underlying LLDD module. You must hold host_lock of the
1138 * parent Scsi_Host or already have a reference when calling this.
1140 int scsi_device_get(struct scsi_device *sdev)
1142 if (sdev->sdev_state == SDEV_DEL)
1144 if (!get_device(&sdev->sdev_gendev))
1146 /* We can fail this if we're doing SCSI operations
1147 * from module exit (like cache flush) */
1148 try_module_get(sdev->host->hostt->module);
1152 EXPORT_SYMBOL(scsi_device_get);
1155 * scsi_device_put - release a reference to a scsi_device
1156 * @sdev: device to release a reference on.
1158 * Description: Release a reference to the scsi_device and decrements the use
1159 * count of the underlying LLDD module. The device is freed once the last
1162 void scsi_device_put(struct scsi_device *sdev)
1164 #ifdef CONFIG_MODULE_UNLOAD
1165 struct module *module = sdev->host->hostt->module;
1167 /* The module refcount will be zero if scsi_device_get()
1168 * was called from a module removal routine */
1169 if (module && module_refcount(module) != 0)
1172 put_device(&sdev->sdev_gendev);
1174 EXPORT_SYMBOL(scsi_device_put);
1176 /* helper for shost_for_each_device, see that for documentation */
1177 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1178 struct scsi_device *prev)
1180 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1181 struct scsi_device *next = NULL;
1182 unsigned long flags;
1184 spin_lock_irqsave(shost->host_lock, flags);
1185 while (list->next != &shost->__devices) {
1186 next = list_entry(list->next, struct scsi_device, siblings);
1187 /* skip devices that we can't get a reference to */
1188 if (!scsi_device_get(next))
1193 spin_unlock_irqrestore(shost->host_lock, flags);
1196 scsi_device_put(prev);
1199 EXPORT_SYMBOL(__scsi_iterate_devices);
1202 * starget_for_each_device - helper to walk all devices of a target
1203 * @starget: target whose devices we want to iterate over.
1204 * @data: Opaque passed to each function call.
1205 * @fn: Function to call on each device
1207 * This traverses over each device of @starget. The devices have
1208 * a reference that must be released by scsi_host_put when breaking
1211 void starget_for_each_device(struct scsi_target *starget, void *data,
1212 void (*fn)(struct scsi_device *, void *))
1214 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1215 struct scsi_device *sdev;
1217 shost_for_each_device(sdev, shost) {
1218 if ((sdev->channel == starget->channel) &&
1219 (sdev->id == starget->id))
1223 EXPORT_SYMBOL(starget_for_each_device);
1226 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1227 * @starget: target whose devices we want to iterate over.
1228 * @data: parameter for callback @fn()
1229 * @fn: callback function that is invoked for each device
1231 * This traverses over each device of @starget. It does _not_
1232 * take a reference on the scsi_device, so the whole loop must be
1233 * protected by shost->host_lock.
1235 * Note: The only reason why drivers would want to use this is because
1236 * they need to access the device list in irq context. Otherwise you
1237 * really want to use starget_for_each_device instead.
1239 void __starget_for_each_device(struct scsi_target *starget, void *data,
1240 void (*fn)(struct scsi_device *, void *))
1242 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1243 struct scsi_device *sdev;
1245 __shost_for_each_device(sdev, shost) {
1246 if ((sdev->channel == starget->channel) &&
1247 (sdev->id == starget->id))
1251 EXPORT_SYMBOL(__starget_for_each_device);
1254 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1255 * @starget: SCSI target pointer
1256 * @lun: SCSI Logical Unit Number
1258 * Description: Looks up the scsi_device with the specified @lun for a given
1259 * @starget. The returned scsi_device does not have an additional
1260 * reference. You must hold the host's host_lock over this call and
1261 * any access to the returned scsi_device. A scsi_device in state
1262 * SDEV_DEL is skipped.
1264 * Note: The only reason why drivers should use this is because
1265 * they need to access the device list in irq context. Otherwise you
1266 * really want to use scsi_device_lookup_by_target instead.
1268 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1271 struct scsi_device *sdev;
1273 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1274 if (sdev->sdev_state == SDEV_DEL)
1276 if (sdev->lun ==lun)
1282 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1285 * scsi_device_lookup_by_target - find a device given the target
1286 * @starget: SCSI target pointer
1287 * @lun: SCSI Logical Unit Number
1289 * Description: Looks up the scsi_device with the specified @lun for a given
1290 * @starget. The returned scsi_device has an additional reference that
1291 * needs to be released with scsi_device_put once you're done with it.
1293 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1296 struct scsi_device *sdev;
1297 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1298 unsigned long flags;
1300 spin_lock_irqsave(shost->host_lock, flags);
1301 sdev = __scsi_device_lookup_by_target(starget, lun);
1302 if (sdev && scsi_device_get(sdev))
1304 spin_unlock_irqrestore(shost->host_lock, flags);
1308 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1311 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1312 * @shost: SCSI host pointer
1313 * @channel: SCSI channel (zero if only one channel)
1314 * @id: SCSI target number (physical unit number)
1315 * @lun: SCSI Logical Unit Number
1317 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1318 * for a given host. The returned scsi_device does not have an additional
1319 * reference. You must hold the host's host_lock over this call and any access
1320 * to the returned scsi_device.
1322 * Note: The only reason why drivers would want to use this is because
1323 * they need to access the device list in irq context. Otherwise you
1324 * really want to use scsi_device_lookup instead.
1326 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1327 uint channel, uint id, u64 lun)
1329 struct scsi_device *sdev;
1331 list_for_each_entry(sdev, &shost->__devices, siblings) {
1332 if (sdev->channel == channel && sdev->id == id &&
1339 EXPORT_SYMBOL(__scsi_device_lookup);
1342 * scsi_device_lookup - find a device given the host
1343 * @shost: SCSI host pointer
1344 * @channel: SCSI channel (zero if only one channel)
1345 * @id: SCSI target number (physical unit number)
1346 * @lun: SCSI Logical Unit Number
1348 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1349 * for a given host. The returned scsi_device has an additional reference that
1350 * needs to be released with scsi_device_put once you're done with it.
1352 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1353 uint channel, uint id, u64 lun)
1355 struct scsi_device *sdev;
1356 unsigned long flags;
1358 spin_lock_irqsave(shost->host_lock, flags);
1359 sdev = __scsi_device_lookup(shost, channel, id, lun);
1360 if (sdev && scsi_device_get(sdev))
1362 spin_unlock_irqrestore(shost->host_lock, flags);
1366 EXPORT_SYMBOL(scsi_device_lookup);
1368 MODULE_DESCRIPTION("SCSI core");
1369 MODULE_LICENSE("GPL");
1371 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1372 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1374 bool scsi_use_blk_mq = false;
1375 module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
1377 static int __init init_scsi(void)
1381 error = scsi_init_queue();
1384 error = scsi_init_procfs();
1387 error = scsi_init_devinfo();
1389 goto cleanup_procfs;
1390 error = scsi_init_hosts();
1392 goto cleanup_devlist;
1393 error = scsi_init_sysctl();
1396 error = scsi_sysfs_register();
1398 goto cleanup_sysctl;
1400 scsi_netlink_init();
1402 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1410 scsi_exit_devinfo();
1415 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1420 static void __exit exit_scsi(void)
1422 scsi_netlink_exit();
1423 scsi_sysfs_unregister();
1426 scsi_exit_devinfo();
1429 async_unregister_domain(&scsi_sd_probe_domain);
1432 subsys_initcall(init_scsi);
1433 module_exit(exit_scsi);