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);
94 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
95 * You may not alter any existing entry (although adding new ones is
96 * encouraged once assigned by ANSI/INCITS T10
98 static const char *const scsi_device_types[] = {
121 * scsi_device_type - Return 17 char string indicating device type.
122 * @type: type number to look up
125 const char * scsi_device_type(unsigned type)
128 return "Well-known LUN ";
131 if (type >= ARRAY_SIZE(scsi_device_types))
133 return scsi_device_types[type];
136 EXPORT_SYMBOL(scsi_device_type);
138 struct scsi_host_cmd_pool {
139 struct kmem_cache *cmd_slab;
140 struct kmem_cache *sense_slab;
144 unsigned int slab_flags;
148 static struct scsi_host_cmd_pool scsi_cmd_pool = {
149 .cmd_name = "scsi_cmd_cache",
150 .sense_name = "scsi_sense_cache",
151 .slab_flags = SLAB_HWCACHE_ALIGN,
154 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
155 .cmd_name = "scsi_cmd_cache(DMA)",
156 .sense_name = "scsi_sense_cache(DMA)",
157 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
158 .gfp_mask = __GFP_DMA,
161 static DEFINE_MUTEX(host_cmd_pool_mutex);
164 * scsi_host_free_command - internal function to release a command
165 * @shost: host to free the command for
166 * @cmd: command to release
168 * the command must previously have been allocated by
169 * scsi_host_alloc_command.
172 scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
174 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
177 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
178 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
179 kmem_cache_free(pool->cmd_slab, cmd);
183 * scsi_host_alloc_command - internal function to allocate command
184 * @shost: SCSI host whose pool to allocate from
185 * @gfp_mask: mask for the allocation
187 * Returns a fully allocated command with sense buffer and protection
188 * data buffer (where applicable) or NULL on failure
190 static struct scsi_cmnd *
191 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
193 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
194 struct scsi_cmnd *cmd;
196 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
200 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
201 gfp_mask | pool->gfp_mask);
202 if (!cmd->sense_buffer)
205 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
206 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
208 goto fail_free_sense;
214 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
216 kmem_cache_free(pool->cmd_slab, cmd);
222 * __scsi_get_command - Allocate a struct scsi_cmnd
223 * @shost: host to transmit command
224 * @gfp_mask: allocation mask
226 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
227 * host's free_list if necessary.
229 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
231 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
233 if (unlikely(!cmd)) {
236 spin_lock_irqsave(&shost->free_list_lock, flags);
237 if (likely(!list_empty(&shost->free_list))) {
238 cmd = list_entry(shost->free_list.next,
239 struct scsi_cmnd, list);
240 list_del_init(&cmd->list);
242 spin_unlock_irqrestore(&shost->free_list_lock, flags);
247 buf = cmd->sense_buffer;
248 prot = cmd->prot_sdb;
250 memset(cmd, 0, sizeof(*cmd));
252 cmd->sense_buffer = buf;
253 cmd->prot_sdb = prot;
259 EXPORT_SYMBOL_GPL(__scsi_get_command);
262 * scsi_get_command - Allocate and setup a scsi command block
263 * @dev: parent scsi device
264 * @gfp_mask: allocator flags
266 * Returns: The allocated scsi command structure.
268 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
270 struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
273 if (unlikely(cmd == NULL))
277 INIT_LIST_HEAD(&cmd->list);
278 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
279 spin_lock_irqsave(&dev->list_lock, flags);
280 list_add_tail(&cmd->list, &dev->cmd_list);
281 spin_unlock_irqrestore(&dev->list_lock, flags);
282 cmd->jiffies_at_alloc = jiffies;
285 EXPORT_SYMBOL(scsi_get_command);
288 * __scsi_put_command - Free a struct scsi_cmnd
290 * @cmd: Command to free
292 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
296 if (unlikely(list_empty(&shost->free_list))) {
297 spin_lock_irqsave(&shost->free_list_lock, flags);
298 if (list_empty(&shost->free_list)) {
299 list_add(&cmd->list, &shost->free_list);
302 spin_unlock_irqrestore(&shost->free_list_lock, flags);
305 if (likely(cmd != NULL))
306 scsi_host_free_command(shost, cmd);
308 EXPORT_SYMBOL(__scsi_put_command);
311 * scsi_put_command - Free a scsi command block
312 * @cmd: command block to free
316 * Notes: The command must not belong to any lists.
318 void scsi_put_command(struct scsi_cmnd *cmd)
322 /* serious error if the command hasn't come from a device list */
323 spin_lock_irqsave(&cmd->device->list_lock, flags);
324 BUG_ON(list_empty(&cmd->list));
325 list_del_init(&cmd->list);
326 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
328 cancel_delayed_work(&cmd->abort_work);
330 __scsi_put_command(cmd->device->host, cmd);
332 EXPORT_SYMBOL(scsi_put_command);
334 static struct scsi_host_cmd_pool *
335 scsi_find_host_cmd_pool(struct Scsi_Host *shost)
337 if (shost->hostt->cmd_size)
338 return shost->hostt->cmd_pool;
339 if (shost->unchecked_isa_dma)
340 return &scsi_cmd_dma_pool;
341 return &scsi_cmd_pool;
345 scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
347 kfree(pool->sense_name);
348 kfree(pool->cmd_name);
352 static struct scsi_host_cmd_pool *
353 scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
355 struct scsi_host_template *hostt = shost->hostt;
356 struct scsi_host_cmd_pool *pool;
358 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
362 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->name);
363 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->name);
364 if (!pool->cmd_name || !pool->sense_name) {
365 scsi_free_host_cmd_pool(pool);
369 pool->slab_flags = SLAB_HWCACHE_ALIGN;
370 if (shost->unchecked_isa_dma) {
371 pool->slab_flags |= SLAB_CACHE_DMA;
372 pool->gfp_mask = __GFP_DMA;
377 static struct scsi_host_cmd_pool *
378 scsi_get_host_cmd_pool(struct Scsi_Host *shost)
380 struct scsi_host_template *hostt = shost->hostt;
381 struct scsi_host_cmd_pool *retval = NULL, *pool;
382 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
385 * Select a command slab for this host and create it if not
388 mutex_lock(&host_cmd_pool_mutex);
389 pool = scsi_find_host_cmd_pool(shost);
391 pool = scsi_alloc_host_cmd_pool(shost);
397 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
398 pool->slab_flags, NULL);
402 pool->sense_slab = kmem_cache_create(pool->sense_name,
403 SCSI_SENSE_BUFFERSIZE, 0,
404 pool->slab_flags, NULL);
405 if (!pool->sense_slab)
412 mutex_unlock(&host_cmd_pool_mutex);
416 kmem_cache_destroy(pool->cmd_slab);
419 scsi_free_host_cmd_pool(pool);
423 static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
425 struct scsi_host_template *hostt = shost->hostt;
426 struct scsi_host_cmd_pool *pool;
428 mutex_lock(&host_cmd_pool_mutex);
429 pool = scsi_find_host_cmd_pool(shost);
432 * This may happen if a driver has a mismatched get and put
433 * of the command pool; the driver should be implicated in
436 BUG_ON(pool->users == 0);
438 if (!--pool->users) {
439 kmem_cache_destroy(pool->cmd_slab);
440 kmem_cache_destroy(pool->sense_slab);
442 scsi_free_host_cmd_pool(pool);
444 mutex_unlock(&host_cmd_pool_mutex);
448 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
449 * @shost: host to allocate the freelist for.
451 * Description: The command freelist protects against system-wide out of memory
452 * deadlock by preallocating one SCSI command structure for each host, so the
453 * system can always write to a swap file on a device associated with that host.
457 int scsi_setup_command_freelist(struct Scsi_Host *shost)
459 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
460 struct scsi_cmnd *cmd;
462 spin_lock_init(&shost->free_list_lock);
463 INIT_LIST_HEAD(&shost->free_list);
465 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
466 if (!shost->cmd_pool)
470 * Get one backup command for this host.
472 cmd = scsi_host_alloc_command(shost, gfp_mask);
474 scsi_put_host_cmd_pool(shost);
475 shost->cmd_pool = NULL;
478 list_add(&cmd->list, &shost->free_list);
483 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
484 * @shost: host whose freelist is going to be destroyed
486 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
489 * If cmd_pool is NULL the free list was not initialized, so
490 * do not attempt to release resources.
492 if (!shost->cmd_pool)
495 while (!list_empty(&shost->free_list)) {
496 struct scsi_cmnd *cmd;
498 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
499 list_del_init(&cmd->list);
500 scsi_host_free_command(shost, cmd);
502 shost->cmd_pool = NULL;
503 scsi_put_host_cmd_pool(shost);
506 #ifdef CONFIG_SCSI_LOGGING
507 void scsi_log_send(struct scsi_cmnd *cmd)
512 * If ML QUEUE log level is greater than or equal to:
514 * 1: nothing (match completion)
516 * 2: log opcode + command of all commands
518 * 3: same as 2 plus dump cmd address
520 * 4: same as 3 plus dump extra junk
522 if (unlikely(scsi_logging_level)) {
523 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
524 SCSI_LOG_MLQUEUE_BITS);
526 scmd_printk(KERN_INFO, cmd, "Send: ");
528 printk("0x%p ", cmd);
530 scsi_print_command(cmd);
532 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
533 " queuecommand 0x%p\n",
534 scsi_sglist(cmd), scsi_bufflen(cmd),
535 cmd->device->host->hostt->queuecommand);
542 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
547 * If ML COMPLETE log level is greater than or equal to:
549 * 1: log disposition, result, opcode + command, and conditionally
550 * sense data for failures or non SUCCESS dispositions.
552 * 2: same as 1 but for all command completions.
554 * 3: same as 2 plus dump cmd address
556 * 4: same as 3 plus dump extra junk
558 if (unlikely(scsi_logging_level)) {
559 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
560 SCSI_LOG_MLCOMPLETE_BITS);
561 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
563 scmd_printk(KERN_INFO, cmd, "Done: ");
565 printk("0x%p ", cmd);
567 * Dump truncated values, so we usually fit within
570 switch (disposition) {
585 * If called via scsi_times_out.
592 scsi_print_result(cmd);
593 scsi_print_command(cmd);
594 if (status_byte(cmd->result) & CHECK_CONDITION)
595 scsi_print_sense("", cmd);
597 scmd_printk(KERN_INFO, cmd,
598 "scsi host busy %d failed %d\n",
599 cmd->device->host->host_busy,
600 cmd->device->host->host_failed);
607 * scsi_cmd_get_serial - Assign a serial number to a command
608 * @host: the scsi host
609 * @cmd: command to assign serial number to
611 * Description: a serial number identifies a request for error recovery
612 * and debugging purposes. Protected by the Host_Lock of host.
614 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
616 cmd->serial_number = host->cmd_serial_number++;
617 if (cmd->serial_number == 0)
618 cmd->serial_number = host->cmd_serial_number++;
620 EXPORT_SYMBOL(scsi_cmd_get_serial);
623 * scsi_dispatch_command - Dispatch a command to the low-level driver.
624 * @cmd: command block we are dispatching.
626 * Return: nonzero return request was rejected and device's queue needs to be
629 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
631 struct Scsi_Host *host = cmd->device->host;
634 atomic_inc(&cmd->device->iorequest_cnt);
636 /* check if the device is still usable */
637 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
638 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
639 * returns an immediate error upwards, and signals
640 * that the device is no longer present */
641 cmd->result = DID_NO_CONNECT << 16;
643 /* return 0 (because the command has been processed) */
647 /* Check to see if the scsi lld made this device blocked. */
648 if (unlikely(scsi_device_blocked(cmd->device))) {
650 * in blocked state, the command is just put back on
651 * the device queue. The suspend state has already
652 * blocked the queue so future requests should not
653 * occur until the device transitions out of the
657 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
659 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
662 * NOTE: rtn is still zero here because we don't need the
663 * queue to be plugged on return (it's already stopped)
669 * If SCSI-2 or lower, store the LUN value in cmnd.
671 if (cmd->device->scsi_level <= SCSI_2 &&
672 cmd->device->scsi_level != SCSI_UNKNOWN) {
673 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
674 (cmd->device->lun << 5 & 0xe0);
680 * Before we queue this command, check if the command
681 * length exceeds what the host adapter can handle.
683 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
685 printk("queuecommand : command too long. "
686 "cdb_size=%d host->max_cmd_len=%d\n",
687 cmd->cmd_len, cmd->device->host->max_cmd_len));
688 cmd->result = (DID_ABORT << 16);
694 if (unlikely(host->shost_state == SHOST_DEL)) {
695 cmd->result = (DID_NO_CONNECT << 16);
698 trace_scsi_dispatch_cmd_start(cmd);
699 cmd->scsi_done = scsi_done;
700 rtn = host->hostt->queuecommand(host, cmd);
704 trace_scsi_dispatch_cmd_error(cmd, rtn);
705 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
706 rtn != SCSI_MLQUEUE_TARGET_BUSY)
707 rtn = SCSI_MLQUEUE_HOST_BUSY;
709 scsi_queue_insert(cmd, rtn);
712 printk("queuecommand : request rejected\n"));
716 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
721 * scsi_done - Invoke completion on finished SCSI command.
722 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
723 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
725 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
726 * which regains ownership of the SCSI command (de facto) from a LLDD, and
727 * calls blk_complete_request() for further processing.
729 * This function is interrupt context safe.
731 static void scsi_done(struct scsi_cmnd *cmd)
733 trace_scsi_dispatch_cmd_done(cmd);
734 blk_complete_request(cmd->request);
738 * scsi_finish_command - cleanup and pass command back to upper layer
741 * Description: Pass command off to upper layer for finishing of I/O
742 * request, waking processes that are waiting on results,
745 void scsi_finish_command(struct scsi_cmnd *cmd)
747 struct scsi_device *sdev = cmd->device;
748 struct scsi_target *starget = scsi_target(sdev);
749 struct Scsi_Host *shost = sdev->host;
750 struct scsi_driver *drv;
751 unsigned int good_bytes;
753 scsi_device_unbusy(sdev);
756 * Clear the flags which say that the device/host is no longer
757 * capable of accepting new commands. These are set in scsi_queue.c
758 * for both the queue full condition on a device, and for a
759 * host full condition on the host.
761 * XXX(hch): What about locking?
763 shost->host_blocked = 0;
764 starget->target_blocked = 0;
765 sdev->device_blocked = 0;
768 * If we have valid sense information, then some kind of recovery
769 * must have taken place. Make a note of this.
771 if (SCSI_SENSE_VALID(cmd))
772 cmd->result |= (DRIVER_SENSE << 24);
774 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
775 "Notifying upper driver of completion "
776 "(result %x)\n", cmd->result));
778 good_bytes = scsi_bufflen(cmd);
779 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
780 int old_good_bytes = good_bytes;
781 drv = scsi_cmd_to_driver(cmd);
783 good_bytes = drv->done(cmd);
785 * USB may not give sense identifying bad sector and
786 * simply return a residue instead, so subtract off the
787 * residue if drv->done() error processing indicates no
788 * change to the completion length.
790 if (good_bytes == old_good_bytes)
791 good_bytes -= scsi_get_resid(cmd);
793 scsi_io_completion(cmd, good_bytes);
795 EXPORT_SYMBOL(scsi_finish_command);
798 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
799 * @sdev: SCSI Device in question
800 * @tagged: Do we use tagged queueing (non-0) or do we treat
801 * this device as an untagged device (0)
802 * @tags: Number of tags allowed if tagged queueing enabled,
803 * or number of commands the low level driver can
804 * queue up in non-tagged mode (as per cmd_per_lun).
808 * Lock Status: None held on entry
810 * Notes: Low level drivers may call this at any time and we will do
811 * the right thing depending on whether or not the device is
812 * currently active and whether or not it even has the
813 * command blocks built yet.
815 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
820 * refuse to set tagged depth to an unworkable size
825 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
828 * Check to see if the queue is managed by the block layer.
829 * If it is, and we fail to adjust the depth, exit.
831 * Do not resize the tag map if it is a host wide share bqt,
832 * because the size should be the hosts's can_queue. If there
833 * is more IO than the LLD's can_queue (so there are not enuogh
834 * tags) request_fn's host queue ready check will handle it.
836 if (!sdev->host->bqt) {
837 if (blk_queue_tagged(sdev->request_queue) &&
838 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
842 sdev->queue_depth = tags;
844 case MSG_ORDERED_TAG:
845 sdev->ordered_tags = 1;
846 sdev->simple_tags = 1;
849 sdev->ordered_tags = 0;
850 sdev->simple_tags = 1;
853 sdev_printk(KERN_WARNING, sdev,
854 "scsi_adjust_queue_depth, bad queue type, "
857 sdev->ordered_tags = sdev->simple_tags = 0;
858 sdev->queue_depth = tags;
862 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
864 EXPORT_SYMBOL(scsi_adjust_queue_depth);
867 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
868 * @sdev: SCSI Device in question
869 * @depth: Current number of outstanding SCSI commands on this device,
870 * not counting the one returned as QUEUE_FULL.
872 * Description: This function will track successive QUEUE_FULL events on a
873 * specific SCSI device to determine if and when there is a
874 * need to adjust the queue depth on the device.
876 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
877 * -1 - Drop back to untagged operation using host->cmd_per_lun
878 * as the untagged command depth
880 * Lock Status: None held on entry
882 * Notes: Low level drivers may call this at any time and we will do
883 * "The Right Thing." We are interrupt context safe.
885 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
889 * Don't let QUEUE_FULLs on the same
890 * jiffies count, they could all be from
893 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
896 sdev->last_queue_full_time = jiffies;
897 if (sdev->last_queue_full_depth != depth) {
898 sdev->last_queue_full_count = 1;
899 sdev->last_queue_full_depth = depth;
901 sdev->last_queue_full_count++;
904 if (sdev->last_queue_full_count <= 10)
906 if (sdev->last_queue_full_depth < 8) {
907 /* Drop back to untagged */
908 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
912 if (sdev->ordered_tags)
913 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
915 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
918 EXPORT_SYMBOL(scsi_track_queue_full);
921 * scsi_vpd_inquiry - Request a device provide us with a VPD page
922 * @sdev: The device to ask
923 * @buffer: Where to put the result
924 * @page: Which Vital Product Data to return
925 * @len: The length of the buffer
927 * This is an internal helper function. You probably want to use
928 * scsi_get_vpd_page instead.
930 * Returns size of the vpd page on success or a negative error number.
932 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
933 u8 page, unsigned len)
936 unsigned char cmd[16];
942 cmd[1] = 1; /* EVPD */
946 cmd[5] = 0; /* Control byte */
949 * I'm not convinced we need to try quite this hard to get VPD, but
950 * all the existing users tried this hard.
952 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
953 len, NULL, 30 * HZ, 3, NULL);
957 /* Sanity check that we got the page back that we asked for */
958 if (buffer[1] != page)
961 return get_unaligned_be16(&buffer[2]) + 4;
965 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
966 * @sdev: The device to ask
967 * @page: Which Vital Product Data to return
968 * @buf: where to store the VPD
969 * @buf_len: number of bytes in the VPD buffer area
971 * SCSI devices may optionally supply Vital Product Data. Each 'page'
972 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
973 * If the device supports this VPD page, this routine returns a pointer
974 * to a buffer containing the data from that page. The caller is
975 * responsible for calling kfree() on this pointer when it is no longer
976 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
978 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
983 if (sdev->skip_vpd_pages)
986 /* Ask for all the pages supported by this device */
987 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
991 /* If the user actually wanted this page, we can skip the rest */
995 for (i = 4; i < min(result, buf_len); i++)
999 if (i < result && i >= buf_len)
1000 /* ran off the end of the buffer, give us benefit of doubt */
1002 /* The device claims it doesn't support the requested page */
1006 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1015 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1018 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
1019 * @sdev: The device to ask
1021 * Attach the 'Device Identification' VPD page (0x83) and the
1022 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
1023 * structure. This information can be used to identify the device
1026 void scsi_attach_vpd(struct scsi_device *sdev)
1029 int vpd_len = SCSI_VPD_PG_LEN;
1030 int pg80_supported = 0;
1031 int pg83_supported = 0;
1032 unsigned char *vpd_buf;
1034 if (sdev->skip_vpd_pages)
1037 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1041 /* Ask for all the pages supported by this device */
1042 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
1047 if (result > vpd_len) {
1053 for (i = 4; i < result; i++) {
1054 if (vpd_buf[i] == 0x80)
1056 if (vpd_buf[i] == 0x83)
1060 vpd_len = SCSI_VPD_PG_LEN;
1062 if (pg80_supported) {
1064 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1068 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
1073 if (result > vpd_len) {
1078 sdev->vpd_pg80_len = result;
1079 sdev->vpd_pg80 = vpd_buf;
1080 vpd_len = SCSI_VPD_PG_LEN;
1083 if (pg83_supported) {
1085 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1089 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
1094 if (result > vpd_len) {
1099 sdev->vpd_pg83_len = result;
1100 sdev->vpd_pg83 = vpd_buf;
1105 * scsi_report_opcode - Find out if a given command opcode is supported
1106 * @sdev: scsi device to query
1107 * @buffer: scratch buffer (must be at least 20 bytes long)
1108 * @len: length of buffer
1109 * @opcode: opcode for command to look up
1111 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1112 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1113 * unsupported and 1 if the device claims to support the command.
1115 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1116 unsigned int len, unsigned char opcode)
1118 unsigned char cmd[16];
1119 struct scsi_sense_hdr sshdr;
1122 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1126 cmd[0] = MAINTENANCE_IN;
1127 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1128 cmd[2] = 1; /* One command format */
1130 put_unaligned_be32(len, &cmd[6]);
1131 memset(buffer, 0, len);
1133 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1134 &sshdr, 30 * HZ, 3, NULL);
1136 if (result && scsi_sense_valid(&sshdr) &&
1137 sshdr.sense_key == ILLEGAL_REQUEST &&
1138 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1141 if ((buffer[1] & 3) == 3) /* Command supported */
1146 EXPORT_SYMBOL(scsi_report_opcode);
1149 * scsi_device_get - get an additional reference to a scsi_device
1150 * @sdev: device to get a reference to
1152 * Description: Gets a reference to the scsi_device and increments the use count
1153 * of the underlying LLDD module. You must hold host_lock of the
1154 * parent Scsi_Host or already have a reference when calling this.
1156 int scsi_device_get(struct scsi_device *sdev)
1158 if (sdev->sdev_state == SDEV_DEL)
1160 if (!get_device(&sdev->sdev_gendev))
1162 /* We can fail this if we're doing SCSI operations
1163 * from module exit (like cache flush) */
1164 try_module_get(sdev->host->hostt->module);
1168 EXPORT_SYMBOL(scsi_device_get);
1171 * scsi_device_put - release a reference to a scsi_device
1172 * @sdev: device to release a reference on.
1174 * Description: Release a reference to the scsi_device and decrements the use
1175 * count of the underlying LLDD module. The device is freed once the last
1178 void scsi_device_put(struct scsi_device *sdev)
1180 #ifdef CONFIG_MODULE_UNLOAD
1181 struct module *module = sdev->host->hostt->module;
1183 /* The module refcount will be zero if scsi_device_get()
1184 * was called from a module removal routine */
1185 if (module && module_refcount(module) != 0)
1188 put_device(&sdev->sdev_gendev);
1190 EXPORT_SYMBOL(scsi_device_put);
1192 /* helper for shost_for_each_device, see that for documentation */
1193 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1194 struct scsi_device *prev)
1196 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1197 struct scsi_device *next = NULL;
1198 unsigned long flags;
1200 spin_lock_irqsave(shost->host_lock, flags);
1201 while (list->next != &shost->__devices) {
1202 next = list_entry(list->next, struct scsi_device, siblings);
1203 /* skip devices that we can't get a reference to */
1204 if (!scsi_device_get(next))
1209 spin_unlock_irqrestore(shost->host_lock, flags);
1212 scsi_device_put(prev);
1215 EXPORT_SYMBOL(__scsi_iterate_devices);
1218 * starget_for_each_device - helper to walk all devices of a target
1219 * @starget: target whose devices we want to iterate over.
1220 * @data: Opaque passed to each function call.
1221 * @fn: Function to call on each device
1223 * This traverses over each device of @starget. The devices have
1224 * a reference that must be released by scsi_host_put when breaking
1227 void starget_for_each_device(struct scsi_target *starget, void *data,
1228 void (*fn)(struct scsi_device *, void *))
1230 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1231 struct scsi_device *sdev;
1233 shost_for_each_device(sdev, shost) {
1234 if ((sdev->channel == starget->channel) &&
1235 (sdev->id == starget->id))
1239 EXPORT_SYMBOL(starget_for_each_device);
1242 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1243 * @starget: target whose devices we want to iterate over.
1244 * @data: parameter for callback @fn()
1245 * @fn: callback function that is invoked for each device
1247 * This traverses over each device of @starget. It does _not_
1248 * take a reference on the scsi_device, so the whole loop must be
1249 * protected by shost->host_lock.
1251 * Note: The only reason why drivers would want to use this is because
1252 * they need to access the device list in irq context. Otherwise you
1253 * really want to use starget_for_each_device instead.
1255 void __starget_for_each_device(struct scsi_target *starget, void *data,
1256 void (*fn)(struct scsi_device *, void *))
1258 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1259 struct scsi_device *sdev;
1261 __shost_for_each_device(sdev, shost) {
1262 if ((sdev->channel == starget->channel) &&
1263 (sdev->id == starget->id))
1267 EXPORT_SYMBOL(__starget_for_each_device);
1270 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1271 * @starget: SCSI target pointer
1272 * @lun: SCSI Logical Unit Number
1274 * Description: Looks up the scsi_device with the specified @lun for a given
1275 * @starget. The returned scsi_device does not have an additional
1276 * reference. You must hold the host's host_lock over this call and
1277 * any access to the returned scsi_device. A scsi_device in state
1278 * SDEV_DEL is skipped.
1280 * Note: The only reason why drivers should use this is because
1281 * they need to access the device list in irq context. Otherwise you
1282 * really want to use scsi_device_lookup_by_target instead.
1284 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1287 struct scsi_device *sdev;
1289 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1290 if (sdev->sdev_state == SDEV_DEL)
1292 if (sdev->lun ==lun)
1298 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1301 * scsi_device_lookup_by_target - find a device given the target
1302 * @starget: SCSI target pointer
1303 * @lun: SCSI Logical Unit Number
1305 * Description: Looks up the scsi_device with the specified @lun for a given
1306 * @starget. The returned scsi_device has an additional reference that
1307 * needs to be released with scsi_device_put once you're done with it.
1309 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1312 struct scsi_device *sdev;
1313 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1314 unsigned long flags;
1316 spin_lock_irqsave(shost->host_lock, flags);
1317 sdev = __scsi_device_lookup_by_target(starget, lun);
1318 if (sdev && scsi_device_get(sdev))
1320 spin_unlock_irqrestore(shost->host_lock, flags);
1324 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1327 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1328 * @shost: SCSI host pointer
1329 * @channel: SCSI channel (zero if only one channel)
1330 * @id: SCSI target number (physical unit number)
1331 * @lun: SCSI Logical Unit Number
1333 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1334 * for a given host. The returned scsi_device does not have an additional
1335 * reference. You must hold the host's host_lock over this call and any access
1336 * to the returned scsi_device.
1338 * Note: The only reason why drivers would want to use this is because
1339 * they need to access the device list in irq context. Otherwise you
1340 * really want to use scsi_device_lookup instead.
1342 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1343 uint channel, uint id, uint lun)
1345 struct scsi_device *sdev;
1347 list_for_each_entry(sdev, &shost->__devices, siblings) {
1348 if (sdev->channel == channel && sdev->id == id &&
1355 EXPORT_SYMBOL(__scsi_device_lookup);
1358 * scsi_device_lookup - find a device given the host
1359 * @shost: SCSI host pointer
1360 * @channel: SCSI channel (zero if only one channel)
1361 * @id: SCSI target number (physical unit number)
1362 * @lun: SCSI Logical Unit Number
1364 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1365 * for a given host. The returned scsi_device has an additional reference that
1366 * needs to be released with scsi_device_put once you're done with it.
1368 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1369 uint channel, uint id, uint lun)
1371 struct scsi_device *sdev;
1372 unsigned long flags;
1374 spin_lock_irqsave(shost->host_lock, flags);
1375 sdev = __scsi_device_lookup(shost, channel, id, lun);
1376 if (sdev && scsi_device_get(sdev))
1378 spin_unlock_irqrestore(shost->host_lock, flags);
1382 EXPORT_SYMBOL(scsi_device_lookup);
1384 MODULE_DESCRIPTION("SCSI core");
1385 MODULE_LICENSE("GPL");
1387 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1388 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1390 static int __init init_scsi(void)
1394 error = scsi_init_queue();
1397 error = scsi_init_procfs();
1400 error = scsi_init_devinfo();
1402 goto cleanup_procfs;
1403 error = scsi_init_hosts();
1405 goto cleanup_devlist;
1406 error = scsi_init_sysctl();
1409 error = scsi_sysfs_register();
1411 goto cleanup_sysctl;
1413 scsi_netlink_init();
1415 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1423 scsi_exit_devinfo();
1428 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1433 static void __exit exit_scsi(void)
1435 scsi_netlink_exit();
1436 scsi_sysfs_unregister();
1439 scsi_exit_devinfo();
1442 async_unregister_domain(&scsi_sd_probe_domain);
1445 subsys_initcall(init_scsi);
1446 module_exit(exit_scsi);