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>
75 static void scsi_done(struct scsi_cmnd *cmd);
78 * Definitions and constants.
82 * Note - the initial logging level can be set here to log events at boot time.
83 * After the system is up, you may enable logging via the /proc interface.
85 unsigned int scsi_logging_level;
86 #if defined(CONFIG_SCSI_LOGGING)
87 EXPORT_SYMBOL(scsi_logging_level);
90 /* sd, scsi core and power management need to coordinate flushing async actions */
91 ASYNC_DOMAIN(scsi_sd_probe_domain);
92 EXPORT_SYMBOL(scsi_sd_probe_domain);
95 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
96 * asynchronous system resume operations. It is marked 'exclusive' to avoid
97 * being included in the async_synchronize_full() that is invoked by
100 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
101 EXPORT_SYMBOL(scsi_sd_pm_domain);
103 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
104 * You may not alter any existing entry (although adding new ones is
105 * encouraged once assigned by ANSI/INCITS T10
107 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 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
240 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
242 if (unlikely(!cmd)) {
245 spin_lock_irqsave(&shost->free_list_lock, flags);
246 if (likely(!list_empty(&shost->free_list))) {
247 cmd = list_entry(shost->free_list.next,
248 struct scsi_cmnd, list);
249 list_del_init(&cmd->list);
251 spin_unlock_irqrestore(&shost->free_list_lock, flags);
256 buf = cmd->sense_buffer;
257 prot = cmd->prot_sdb;
259 memset(cmd, 0, sizeof(*cmd));
261 cmd->sense_buffer = buf;
262 cmd->prot_sdb = prot;
268 EXPORT_SYMBOL_GPL(__scsi_get_command);
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;
294 EXPORT_SYMBOL(scsi_get_command);
297 * __scsi_put_command - Free a struct scsi_cmnd
299 * @cmd: Command to free
301 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
305 if (unlikely(list_empty(&shost->free_list))) {
306 spin_lock_irqsave(&shost->free_list_lock, flags);
307 if (list_empty(&shost->free_list)) {
308 list_add(&cmd->list, &shost->free_list);
311 spin_unlock_irqrestore(&shost->free_list_lock, flags);
314 if (likely(cmd != NULL))
315 scsi_host_free_command(shost, cmd);
317 EXPORT_SYMBOL(__scsi_put_command);
320 * scsi_put_command - Free a scsi command block
321 * @cmd: command block to free
325 * Notes: The command must not belong to any lists.
327 void scsi_put_command(struct scsi_cmnd *cmd)
331 /* serious error if the command hasn't come from a device list */
332 spin_lock_irqsave(&cmd->device->list_lock, flags);
333 BUG_ON(list_empty(&cmd->list));
334 list_del_init(&cmd->list);
335 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
337 cancel_delayed_work(&cmd->abort_work);
339 __scsi_put_command(cmd->device->host, cmd);
341 EXPORT_SYMBOL(scsi_put_command);
343 static struct scsi_host_cmd_pool *
344 scsi_find_host_cmd_pool(struct Scsi_Host *shost)
346 if (shost->hostt->cmd_size)
347 return shost->hostt->cmd_pool;
348 if (shost->unchecked_isa_dma)
349 return &scsi_cmd_dma_pool;
350 return &scsi_cmd_pool;
354 scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
356 kfree(pool->sense_name);
357 kfree(pool->cmd_name);
361 static struct scsi_host_cmd_pool *
362 scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
364 struct scsi_host_template *hostt = shost->hostt;
365 struct scsi_host_cmd_pool *pool;
367 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
371 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->name);
372 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->name);
373 if (!pool->cmd_name || !pool->sense_name) {
374 scsi_free_host_cmd_pool(pool);
378 pool->slab_flags = SLAB_HWCACHE_ALIGN;
379 if (shost->unchecked_isa_dma) {
380 pool->slab_flags |= SLAB_CACHE_DMA;
381 pool->gfp_mask = __GFP_DMA;
386 static struct scsi_host_cmd_pool *
387 scsi_get_host_cmd_pool(struct Scsi_Host *shost)
389 struct scsi_host_template *hostt = shost->hostt;
390 struct scsi_host_cmd_pool *retval = NULL, *pool;
391 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
394 * Select a command slab for this host and create it if not
397 mutex_lock(&host_cmd_pool_mutex);
398 pool = scsi_find_host_cmd_pool(shost);
400 pool = scsi_alloc_host_cmd_pool(shost);
406 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
407 pool->slab_flags, NULL);
411 pool->sense_slab = kmem_cache_create(pool->sense_name,
412 SCSI_SENSE_BUFFERSIZE, 0,
413 pool->slab_flags, NULL);
414 if (!pool->sense_slab)
421 mutex_unlock(&host_cmd_pool_mutex);
425 kmem_cache_destroy(pool->cmd_slab);
428 scsi_free_host_cmd_pool(pool);
432 static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
434 struct scsi_host_template *hostt = shost->hostt;
435 struct scsi_host_cmd_pool *pool;
437 mutex_lock(&host_cmd_pool_mutex);
438 pool = scsi_find_host_cmd_pool(shost);
441 * This may happen if a driver has a mismatched get and put
442 * of the command pool; the driver should be implicated in
445 BUG_ON(pool->users == 0);
447 if (!--pool->users) {
448 kmem_cache_destroy(pool->cmd_slab);
449 kmem_cache_destroy(pool->sense_slab);
451 scsi_free_host_cmd_pool(pool);
453 mutex_unlock(&host_cmd_pool_mutex);
457 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
458 * @shost: host to allocate the freelist for.
460 * Description: The command freelist protects against system-wide out of memory
461 * deadlock by preallocating one SCSI command structure for each host, so the
462 * system can always write to a swap file on a device associated with that host.
466 int scsi_setup_command_freelist(struct Scsi_Host *shost)
468 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
469 struct scsi_cmnd *cmd;
471 spin_lock_init(&shost->free_list_lock);
472 INIT_LIST_HEAD(&shost->free_list);
474 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
475 if (!shost->cmd_pool)
479 * Get one backup command for this host.
481 cmd = scsi_host_alloc_command(shost, gfp_mask);
483 scsi_put_host_cmd_pool(shost);
484 shost->cmd_pool = NULL;
487 list_add(&cmd->list, &shost->free_list);
492 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
493 * @shost: host whose freelist is going to be destroyed
495 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
498 * If cmd_pool is NULL the free list was not initialized, so
499 * do not attempt to release resources.
501 if (!shost->cmd_pool)
504 while (!list_empty(&shost->free_list)) {
505 struct scsi_cmnd *cmd;
507 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
508 list_del_init(&cmd->list);
509 scsi_host_free_command(shost, cmd);
511 shost->cmd_pool = NULL;
512 scsi_put_host_cmd_pool(shost);
515 #ifdef CONFIG_SCSI_LOGGING
516 void scsi_log_send(struct scsi_cmnd *cmd)
521 * If ML QUEUE log level is greater than or equal to:
523 * 1: nothing (match completion)
525 * 2: log opcode + command of all commands
527 * 3: same as 2 plus dump cmd address
529 * 4: same as 3 plus dump extra junk
531 if (unlikely(scsi_logging_level)) {
532 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
533 SCSI_LOG_MLQUEUE_BITS);
535 scmd_printk(KERN_INFO, cmd, "Send: ");
537 printk("0x%p ", cmd);
539 scsi_print_command(cmd);
541 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
542 " queuecommand 0x%p\n",
543 scsi_sglist(cmd), scsi_bufflen(cmd),
544 cmd->device->host->hostt->queuecommand);
551 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
556 * If ML COMPLETE log level is greater than or equal to:
558 * 1: log disposition, result, opcode + command, and conditionally
559 * sense data for failures or non SUCCESS dispositions.
561 * 2: same as 1 but for all command completions.
563 * 3: same as 2 plus dump cmd address
565 * 4: same as 3 plus dump extra junk
567 if (unlikely(scsi_logging_level)) {
568 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
569 SCSI_LOG_MLCOMPLETE_BITS);
570 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
572 scmd_printk(KERN_INFO, cmd, "Done: ");
574 printk("0x%p ", cmd);
576 * Dump truncated values, so we usually fit within
579 switch (disposition) {
594 * If called via scsi_times_out.
601 scsi_print_result(cmd);
602 scsi_print_command(cmd);
603 if (status_byte(cmd->result) & CHECK_CONDITION)
604 scsi_print_sense("", cmd);
606 scmd_printk(KERN_INFO, cmd,
607 "scsi host busy %d failed %d\n",
608 cmd->device->host->host_busy,
609 cmd->device->host->host_failed);
616 * scsi_cmd_get_serial - Assign a serial number to a command
617 * @host: the scsi host
618 * @cmd: command to assign serial number to
620 * Description: a serial number identifies a request for error recovery
621 * and debugging purposes. Protected by the Host_Lock of host.
623 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
625 cmd->serial_number = host->cmd_serial_number++;
626 if (cmd->serial_number == 0)
627 cmd->serial_number = host->cmd_serial_number++;
629 EXPORT_SYMBOL(scsi_cmd_get_serial);
632 * scsi_dispatch_command - Dispatch a command to the low-level driver.
633 * @cmd: command block we are dispatching.
635 * Return: nonzero return request was rejected and device's queue needs to be
638 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
640 struct Scsi_Host *host = cmd->device->host;
643 atomic_inc(&cmd->device->iorequest_cnt);
645 /* check if the device is still usable */
646 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
647 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
648 * returns an immediate error upwards, and signals
649 * that the device is no longer present */
650 cmd->result = DID_NO_CONNECT << 16;
652 /* return 0 (because the command has been processed) */
656 /* Check to see if the scsi lld made this device blocked. */
657 if (unlikely(scsi_device_blocked(cmd->device))) {
659 * in blocked state, the command is just put back on
660 * the device queue. The suspend state has already
661 * blocked the queue so future requests should not
662 * occur until the device transitions out of the
666 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
668 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
671 * NOTE: rtn is still zero here because we don't need the
672 * queue to be plugged on return (it's already stopped)
678 * If SCSI-2 or lower, store the LUN value in cmnd.
680 if (cmd->device->scsi_level <= SCSI_2 &&
681 cmd->device->scsi_level != SCSI_UNKNOWN) {
682 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
683 (cmd->device->lun << 5 & 0xe0);
689 * Before we queue this command, check if the command
690 * length exceeds what the host adapter can handle.
692 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
694 printk("queuecommand : command too long. "
695 "cdb_size=%d host->max_cmd_len=%d\n",
696 cmd->cmd_len, cmd->device->host->max_cmd_len));
697 cmd->result = (DID_ABORT << 16);
703 if (unlikely(host->shost_state == SHOST_DEL)) {
704 cmd->result = (DID_NO_CONNECT << 16);
707 trace_scsi_dispatch_cmd_start(cmd);
708 cmd->scsi_done = scsi_done;
709 rtn = host->hostt->queuecommand(host, cmd);
713 trace_scsi_dispatch_cmd_error(cmd, rtn);
714 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
715 rtn != SCSI_MLQUEUE_TARGET_BUSY)
716 rtn = SCSI_MLQUEUE_HOST_BUSY;
718 scsi_queue_insert(cmd, rtn);
721 printk("queuecommand : request rejected\n"));
725 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
730 * scsi_done - Invoke completion on finished SCSI command.
731 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
732 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
734 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
735 * which regains ownership of the SCSI command (de facto) from a LLDD, and
736 * calls blk_complete_request() for further processing.
738 * This function is interrupt context safe.
740 static void scsi_done(struct scsi_cmnd *cmd)
742 trace_scsi_dispatch_cmd_done(cmd);
743 blk_complete_request(cmd->request);
747 * scsi_finish_command - cleanup and pass command back to upper layer
750 * Description: Pass command off to upper layer for finishing of I/O
751 * request, waking processes that are waiting on results,
754 void scsi_finish_command(struct scsi_cmnd *cmd)
756 struct scsi_device *sdev = cmd->device;
757 struct scsi_target *starget = scsi_target(sdev);
758 struct Scsi_Host *shost = sdev->host;
759 struct scsi_driver *drv;
760 unsigned int good_bytes;
762 scsi_device_unbusy(sdev);
765 * Clear the flags which say that the device/host is no longer
766 * capable of accepting new commands. These are set in scsi_queue.c
767 * for both the queue full condition on a device, and for a
768 * host full condition on the host.
770 * XXX(hch): What about locking?
772 shost->host_blocked = 0;
773 starget->target_blocked = 0;
774 sdev->device_blocked = 0;
777 * If we have valid sense information, then some kind of recovery
778 * must have taken place. Make a note of this.
780 if (SCSI_SENSE_VALID(cmd))
781 cmd->result |= (DRIVER_SENSE << 24);
783 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
784 "Notifying upper driver of completion "
785 "(result %x)\n", cmd->result));
787 good_bytes = scsi_bufflen(cmd);
788 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
789 int old_good_bytes = good_bytes;
790 drv = scsi_cmd_to_driver(cmd);
792 good_bytes = drv->done(cmd);
794 * USB may not give sense identifying bad sector and
795 * simply return a residue instead, so subtract off the
796 * residue if drv->done() error processing indicates no
797 * change to the completion length.
799 if (good_bytes == old_good_bytes)
800 good_bytes -= scsi_get_resid(cmd);
802 scsi_io_completion(cmd, good_bytes);
804 EXPORT_SYMBOL(scsi_finish_command);
807 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
808 * @sdev: SCSI Device in question
809 * @tagged: Do we use tagged queueing (non-0) or do we treat
810 * this device as an untagged device (0)
811 * @tags: Number of tags allowed if tagged queueing enabled,
812 * or number of commands the low level driver can
813 * queue up in non-tagged mode (as per cmd_per_lun).
817 * Lock Status: None held on entry
819 * Notes: Low level drivers may call this at any time and we will do
820 * the right thing depending on whether or not the device is
821 * currently active and whether or not it even has the
822 * command blocks built yet.
824 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
829 * refuse to set tagged depth to an unworkable size
834 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
837 * Check to see if the queue is managed by the block layer.
838 * If it is, and we fail to adjust the depth, exit.
840 * Do not resize the tag map if it is a host wide share bqt,
841 * because the size should be the hosts's can_queue. If there
842 * is more IO than the LLD's can_queue (so there are not enuogh
843 * tags) request_fn's host queue ready check will handle it.
845 if (!sdev->host->bqt) {
846 if (blk_queue_tagged(sdev->request_queue) &&
847 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
851 sdev->queue_depth = tags;
853 case MSG_ORDERED_TAG:
854 sdev->ordered_tags = 1;
855 sdev->simple_tags = 1;
858 sdev->ordered_tags = 0;
859 sdev->simple_tags = 1;
862 sdev_printk(KERN_WARNING, sdev,
863 "scsi_adjust_queue_depth, bad queue type, "
866 sdev->ordered_tags = sdev->simple_tags = 0;
867 sdev->queue_depth = tags;
871 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
873 EXPORT_SYMBOL(scsi_adjust_queue_depth);
876 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
877 * @sdev: SCSI Device in question
878 * @depth: Current number of outstanding SCSI commands on this device,
879 * not counting the one returned as QUEUE_FULL.
881 * Description: This function will track successive QUEUE_FULL events on a
882 * specific SCSI device to determine if and when there is a
883 * need to adjust the queue depth on the device.
885 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
886 * -1 - Drop back to untagged operation using host->cmd_per_lun
887 * as the untagged command depth
889 * Lock Status: None held on entry
891 * Notes: Low level drivers may call this at any time and we will do
892 * "The Right Thing." We are interrupt context safe.
894 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
898 * Don't let QUEUE_FULLs on the same
899 * jiffies count, they could all be from
902 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
905 sdev->last_queue_full_time = jiffies;
906 if (sdev->last_queue_full_depth != depth) {
907 sdev->last_queue_full_count = 1;
908 sdev->last_queue_full_depth = depth;
910 sdev->last_queue_full_count++;
913 if (sdev->last_queue_full_count <= 10)
915 if (sdev->last_queue_full_depth < 8) {
916 /* Drop back to untagged */
917 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
921 if (sdev->ordered_tags)
922 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
924 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
927 EXPORT_SYMBOL(scsi_track_queue_full);
930 * scsi_vpd_inquiry - Request a device provide us with a VPD page
931 * @sdev: The device to ask
932 * @buffer: Where to put the result
933 * @page: Which Vital Product Data to return
934 * @len: The length of the buffer
936 * This is an internal helper function. You probably want to use
937 * scsi_get_vpd_page instead.
939 * Returns size of the vpd page on success or a negative error number.
941 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
942 u8 page, unsigned len)
945 unsigned char cmd[16];
951 cmd[1] = 1; /* EVPD */
955 cmd[5] = 0; /* Control byte */
958 * I'm not convinced we need to try quite this hard to get VPD, but
959 * all the existing users tried this hard.
961 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
962 len, NULL, 30 * HZ, 3, NULL);
966 /* Sanity check that we got the page back that we asked for */
967 if (buffer[1] != page)
970 return get_unaligned_be16(&buffer[2]) + 4;
974 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
975 * @sdev: The device to ask
976 * @page: Which Vital Product Data to return
977 * @buf: where to store the VPD
978 * @buf_len: number of bytes in the VPD buffer area
980 * SCSI devices may optionally supply Vital Product Data. Each 'page'
981 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
982 * If the device supports this VPD page, this routine returns a pointer
983 * to a buffer containing the data from that page. The caller is
984 * responsible for calling kfree() on this pointer when it is no longer
985 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
987 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
992 if (sdev->skip_vpd_pages)
995 /* Ask for all the pages supported by this device */
996 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1000 /* If the user actually wanted this page, we can skip the rest */
1004 for (i = 4; i < min(result, buf_len); i++)
1008 if (i < result && i >= buf_len)
1009 /* ran off the end of the buffer, give us benefit of doubt */
1011 /* The device claims it doesn't support the requested page */
1015 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1024 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1027 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
1028 * @sdev: The device to ask
1030 * Attach the 'Device Identification' VPD page (0x83) and the
1031 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
1032 * structure. This information can be used to identify the device
1035 void scsi_attach_vpd(struct scsi_device *sdev)
1038 int vpd_len = SCSI_VPD_PG_LEN;
1039 int pg80_supported = 0;
1040 int pg83_supported = 0;
1041 unsigned char *vpd_buf;
1043 if (sdev->skip_vpd_pages)
1046 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1050 /* Ask for all the pages supported by this device */
1051 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
1056 if (result > vpd_len) {
1062 for (i = 4; i < result; i++) {
1063 if (vpd_buf[i] == 0x80)
1065 if (vpd_buf[i] == 0x83)
1069 vpd_len = SCSI_VPD_PG_LEN;
1071 if (pg80_supported) {
1073 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1077 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
1082 if (result > vpd_len) {
1087 sdev->vpd_pg80_len = result;
1088 sdev->vpd_pg80 = vpd_buf;
1089 vpd_len = SCSI_VPD_PG_LEN;
1092 if (pg83_supported) {
1094 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1098 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
1103 if (result > vpd_len) {
1108 sdev->vpd_pg83_len = result;
1109 sdev->vpd_pg83 = vpd_buf;
1114 * scsi_report_opcode - Find out if a given command opcode is supported
1115 * @sdev: scsi device to query
1116 * @buffer: scratch buffer (must be at least 20 bytes long)
1117 * @len: length of buffer
1118 * @opcode: opcode for command to look up
1120 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1121 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1122 * unsupported and 1 if the device claims to support the command.
1124 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1125 unsigned int len, unsigned char opcode)
1127 unsigned char cmd[16];
1128 struct scsi_sense_hdr sshdr;
1131 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1135 cmd[0] = MAINTENANCE_IN;
1136 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1137 cmd[2] = 1; /* One command format */
1139 put_unaligned_be32(len, &cmd[6]);
1140 memset(buffer, 0, len);
1142 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1143 &sshdr, 30 * HZ, 3, NULL);
1145 if (result && scsi_sense_valid(&sshdr) &&
1146 sshdr.sense_key == ILLEGAL_REQUEST &&
1147 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1150 if ((buffer[1] & 3) == 3) /* Command supported */
1155 EXPORT_SYMBOL(scsi_report_opcode);
1158 * scsi_device_get - get an additional reference to a scsi_device
1159 * @sdev: device to get a reference to
1161 * Description: Gets a reference to the scsi_device and increments the use count
1162 * of the underlying LLDD module. You must hold host_lock of the
1163 * parent Scsi_Host or already have a reference when calling this.
1165 int scsi_device_get(struct scsi_device *sdev)
1167 if (sdev->sdev_state == SDEV_DEL)
1169 if (!get_device(&sdev->sdev_gendev))
1171 /* We can fail this if we're doing SCSI operations
1172 * from module exit (like cache flush) */
1173 try_module_get(sdev->host->hostt->module);
1177 EXPORT_SYMBOL(scsi_device_get);
1180 * scsi_device_put - release a reference to a scsi_device
1181 * @sdev: device to release a reference on.
1183 * Description: Release a reference to the scsi_device and decrements the use
1184 * count of the underlying LLDD module. The device is freed once the last
1187 void scsi_device_put(struct scsi_device *sdev)
1189 #ifdef CONFIG_MODULE_UNLOAD
1190 struct module *module = sdev->host->hostt->module;
1192 /* The module refcount will be zero if scsi_device_get()
1193 * was called from a module removal routine */
1194 if (module && module_refcount(module) != 0)
1197 put_device(&sdev->sdev_gendev);
1199 EXPORT_SYMBOL(scsi_device_put);
1201 /* helper for shost_for_each_device, see that for documentation */
1202 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1203 struct scsi_device *prev)
1205 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1206 struct scsi_device *next = NULL;
1207 unsigned long flags;
1209 spin_lock_irqsave(shost->host_lock, flags);
1210 while (list->next != &shost->__devices) {
1211 next = list_entry(list->next, struct scsi_device, siblings);
1212 /* skip devices that we can't get a reference to */
1213 if (!scsi_device_get(next))
1218 spin_unlock_irqrestore(shost->host_lock, flags);
1221 scsi_device_put(prev);
1224 EXPORT_SYMBOL(__scsi_iterate_devices);
1227 * starget_for_each_device - helper to walk all devices of a target
1228 * @starget: target whose devices we want to iterate over.
1229 * @data: Opaque passed to each function call.
1230 * @fn: Function to call on each device
1232 * This traverses over each device of @starget. The devices have
1233 * a reference that must be released by scsi_host_put when breaking
1236 void starget_for_each_device(struct scsi_target *starget, void *data,
1237 void (*fn)(struct scsi_device *, void *))
1239 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1240 struct scsi_device *sdev;
1242 shost_for_each_device(sdev, shost) {
1243 if ((sdev->channel == starget->channel) &&
1244 (sdev->id == starget->id))
1248 EXPORT_SYMBOL(starget_for_each_device);
1251 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1252 * @starget: target whose devices we want to iterate over.
1253 * @data: parameter for callback @fn()
1254 * @fn: callback function that is invoked for each device
1256 * This traverses over each device of @starget. It does _not_
1257 * take a reference on the scsi_device, so the whole loop must be
1258 * protected by shost->host_lock.
1260 * Note: The only reason why drivers would want to use this is because
1261 * they need to access the device list in irq context. Otherwise you
1262 * really want to use starget_for_each_device instead.
1264 void __starget_for_each_device(struct scsi_target *starget, void *data,
1265 void (*fn)(struct scsi_device *, void *))
1267 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1268 struct scsi_device *sdev;
1270 __shost_for_each_device(sdev, shost) {
1271 if ((sdev->channel == starget->channel) &&
1272 (sdev->id == starget->id))
1276 EXPORT_SYMBOL(__starget_for_each_device);
1279 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1280 * @starget: SCSI target pointer
1281 * @lun: SCSI Logical Unit Number
1283 * Description: Looks up the scsi_device with the specified @lun for a given
1284 * @starget. The returned scsi_device does not have an additional
1285 * reference. You must hold the host's host_lock over this call and
1286 * any access to the returned scsi_device. A scsi_device in state
1287 * SDEV_DEL is skipped.
1289 * Note: The only reason why drivers should use this is because
1290 * they need to access the device list in irq context. Otherwise you
1291 * really want to use scsi_device_lookup_by_target instead.
1293 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1296 struct scsi_device *sdev;
1298 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1299 if (sdev->sdev_state == SDEV_DEL)
1301 if (sdev->lun ==lun)
1307 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1310 * scsi_device_lookup_by_target - find a device given the target
1311 * @starget: SCSI target pointer
1312 * @lun: SCSI Logical Unit Number
1314 * Description: Looks up the scsi_device with the specified @lun for a given
1315 * @starget. The returned scsi_device has an additional reference that
1316 * needs to be released with scsi_device_put once you're done with it.
1318 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1321 struct scsi_device *sdev;
1322 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1323 unsigned long flags;
1325 spin_lock_irqsave(shost->host_lock, flags);
1326 sdev = __scsi_device_lookup_by_target(starget, lun);
1327 if (sdev && scsi_device_get(sdev))
1329 spin_unlock_irqrestore(shost->host_lock, flags);
1333 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1336 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1337 * @shost: SCSI host pointer
1338 * @channel: SCSI channel (zero if only one channel)
1339 * @id: SCSI target number (physical unit number)
1340 * @lun: SCSI Logical Unit Number
1342 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1343 * for a given host. The returned scsi_device does not have an additional
1344 * reference. You must hold the host's host_lock over this call and any access
1345 * to the returned scsi_device.
1347 * Note: The only reason why drivers would want to use this is because
1348 * they need to access the device list in irq context. Otherwise you
1349 * really want to use scsi_device_lookup instead.
1351 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1352 uint channel, uint id, uint lun)
1354 struct scsi_device *sdev;
1356 list_for_each_entry(sdev, &shost->__devices, siblings) {
1357 if (sdev->channel == channel && sdev->id == id &&
1364 EXPORT_SYMBOL(__scsi_device_lookup);
1367 * scsi_device_lookup - find a device given the host
1368 * @shost: SCSI host pointer
1369 * @channel: SCSI channel (zero if only one channel)
1370 * @id: SCSI target number (physical unit number)
1371 * @lun: SCSI Logical Unit Number
1373 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1374 * for a given host. The returned scsi_device has an additional reference that
1375 * needs to be released with scsi_device_put once you're done with it.
1377 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1378 uint channel, uint id, uint lun)
1380 struct scsi_device *sdev;
1381 unsigned long flags;
1383 spin_lock_irqsave(shost->host_lock, flags);
1384 sdev = __scsi_device_lookup(shost, channel, id, lun);
1385 if (sdev && scsi_device_get(sdev))
1387 spin_unlock_irqrestore(shost->host_lock, flags);
1391 EXPORT_SYMBOL(scsi_device_lookup);
1393 MODULE_DESCRIPTION("SCSI core");
1394 MODULE_LICENSE("GPL");
1396 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1397 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1399 static int __init init_scsi(void)
1403 error = scsi_init_queue();
1406 error = scsi_init_procfs();
1409 error = scsi_init_devinfo();
1411 goto cleanup_procfs;
1412 error = scsi_init_hosts();
1414 goto cleanup_devlist;
1415 error = scsi_init_sysctl();
1418 error = scsi_sysfs_register();
1420 goto cleanup_sysctl;
1422 scsi_netlink_init();
1424 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1432 scsi_exit_devinfo();
1437 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1442 static void __exit exit_scsi(void)
1444 scsi_netlink_exit();
1445 scsi_sysfs_unregister();
1448 scsi_exit_devinfo();
1451 async_unregister_domain(&scsi_sd_probe_domain);
1454 subsys_initcall(init_scsi);
1455 module_exit(exit_scsi);