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>
58 #include <scsi/scsi.h>
59 #include <scsi/scsi_cmnd.h>
60 #include <scsi/scsi_dbg.h>
61 #include <scsi/scsi_device.h>
62 #include <scsi/scsi_driver.h>
63 #include <scsi/scsi_eh.h>
64 #include <scsi/scsi_host.h>
65 #include <scsi/scsi_tcq.h>
67 #include "scsi_priv.h"
68 #include "scsi_logging.h"
70 static void scsi_done(struct scsi_cmnd *cmd);
73 * Definitions and constants.
76 #define MIN_RESET_DELAY (2*HZ)
78 /* Do not call reset on error if we just did a reset within 15 sec. */
79 #define MIN_RESET_PERIOD (15*HZ)
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 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
91 * You may not alter any existing entry (although adding new ones is
92 * encouraged once assigned by ANSI/INCITS T10
94 static const char *const scsi_device_types[] = {
117 * scsi_device_type - Return 17 char string indicating device type.
118 * @type: type number to look up
121 const char * scsi_device_type(unsigned type)
124 return "Well-known LUN ";
127 if (type >= ARRAY_SIZE(scsi_device_types))
129 return scsi_device_types[type];
132 EXPORT_SYMBOL(scsi_device_type);
134 struct scsi_host_cmd_pool {
135 struct kmem_cache *cmd_slab;
136 struct kmem_cache *sense_slab;
140 unsigned int slab_flags;
144 static struct scsi_host_cmd_pool scsi_cmd_pool = {
145 .cmd_name = "scsi_cmd_cache",
146 .sense_name = "scsi_sense_cache",
147 .slab_flags = SLAB_HWCACHE_ALIGN,
150 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
151 .cmd_name = "scsi_cmd_cache(DMA)",
152 .sense_name = "scsi_sense_cache(DMA)",
153 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
154 .gfp_mask = __GFP_DMA,
157 static DEFINE_MUTEX(host_cmd_pool_mutex);
160 * scsi_pool_alloc_command - internal function to get a fully allocated command
161 * @pool: slab pool to allocate the command from
162 * @gfp_mask: mask for the allocation
164 * Returns a fully allocated command (with the allied sense buffer) or
167 static struct scsi_cmnd *
168 scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
170 struct scsi_cmnd *cmd;
172 cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
176 memset(cmd, 0, sizeof(*cmd));
178 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
179 gfp_mask | pool->gfp_mask);
180 if (!cmd->sense_buffer) {
181 kmem_cache_free(pool->cmd_slab, cmd);
189 * scsi_pool_free_command - internal function to release a command
190 * @pool: slab pool to allocate the command from
191 * @cmd: command to release
193 * the command must previously have been allocated by
194 * scsi_pool_alloc_command.
197 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
198 struct scsi_cmnd *cmd)
201 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
203 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
204 kmem_cache_free(pool->cmd_slab, cmd);
208 * scsi_host_alloc_command - internal function to allocate command
209 * @shost: SCSI host whose pool to allocate from
210 * @gfp_mask: mask for the allocation
212 * Returns a fully allocated command with sense buffer and protection
213 * data buffer (where applicable) or NULL on failure
215 static struct scsi_cmnd *
216 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
218 struct scsi_cmnd *cmd;
220 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
224 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
225 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
227 if (!cmd->prot_sdb) {
228 scsi_pool_free_command(shost->cmd_pool, cmd);
237 * __scsi_get_command - Allocate a struct scsi_cmnd
238 * @shost: host to transmit command
239 * @gfp_mask: allocation mask
241 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
242 * host's free_list if necessary.
244 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
246 struct scsi_cmnd *cmd;
249 cmd = scsi_host_alloc_command(shost, gfp_mask);
251 if (unlikely(!cmd)) {
254 spin_lock_irqsave(&shost->free_list_lock, flags);
255 if (likely(!list_empty(&shost->free_list))) {
256 cmd = list_entry(shost->free_list.next,
257 struct scsi_cmnd, list);
258 list_del_init(&cmd->list);
260 spin_unlock_irqrestore(&shost->free_list_lock, flags);
263 buf = cmd->sense_buffer;
264 memset(cmd, 0, sizeof(*cmd));
265 cmd->sense_buffer = buf;
271 EXPORT_SYMBOL_GPL(__scsi_get_command);
274 * scsi_get_command - Allocate and setup a scsi command block
275 * @dev: parent scsi device
276 * @gfp_mask: allocator flags
278 * Returns: The allocated scsi command structure.
280 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
282 struct scsi_cmnd *cmd;
284 /* Bail if we can't get a reference to the device */
285 if (!get_device(&dev->sdev_gendev))
288 cmd = __scsi_get_command(dev->host, gfp_mask);
290 if (likely(cmd != NULL)) {
294 init_timer(&cmd->eh_timeout);
295 INIT_LIST_HEAD(&cmd->list);
296 spin_lock_irqsave(&dev->list_lock, flags);
297 list_add_tail(&cmd->list, &dev->cmd_list);
298 spin_unlock_irqrestore(&dev->list_lock, flags);
299 cmd->jiffies_at_alloc = jiffies;
301 put_device(&dev->sdev_gendev);
305 EXPORT_SYMBOL(scsi_get_command);
308 * __scsi_put_command - Free a struct scsi_cmnd
310 * @cmd: Command to free
311 * @dev: parent scsi device
313 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
318 /* changing locks here, don't need to restore the irq state */
319 spin_lock_irqsave(&shost->free_list_lock, flags);
320 if (unlikely(list_empty(&shost->free_list))) {
321 list_add(&cmd->list, &shost->free_list);
324 spin_unlock_irqrestore(&shost->free_list_lock, flags);
326 if (likely(cmd != NULL))
327 scsi_pool_free_command(shost->cmd_pool, cmd);
331 EXPORT_SYMBOL(__scsi_put_command);
334 * scsi_put_command - Free a scsi command block
335 * @cmd: command block to free
339 * Notes: The command must not belong to any lists.
341 void scsi_put_command(struct scsi_cmnd *cmd)
343 struct scsi_device *sdev = cmd->device;
346 /* serious error if the command hasn't come from a device list */
347 spin_lock_irqsave(&cmd->device->list_lock, flags);
348 BUG_ON(list_empty(&cmd->list));
349 list_del_init(&cmd->list);
350 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
352 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
354 EXPORT_SYMBOL(scsi_put_command);
356 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
358 struct scsi_host_cmd_pool *retval = NULL, *pool;
360 * Select a command slab for this host and create it if not
363 mutex_lock(&host_cmd_pool_mutex);
364 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
367 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
368 sizeof(struct scsi_cmnd), 0,
369 pool->slab_flags, NULL);
373 pool->sense_slab = kmem_cache_create(pool->sense_name,
374 SCSI_SENSE_BUFFERSIZE, 0,
375 pool->slab_flags, NULL);
376 if (!pool->sense_slab) {
377 kmem_cache_destroy(pool->cmd_slab);
385 mutex_unlock(&host_cmd_pool_mutex);
389 static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
391 struct scsi_host_cmd_pool *pool;
393 mutex_lock(&host_cmd_pool_mutex);
394 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
397 * This may happen if a driver has a mismatched get and put
398 * of the command pool; the driver should be implicated in
401 BUG_ON(pool->users == 0);
403 if (!--pool->users) {
404 kmem_cache_destroy(pool->cmd_slab);
405 kmem_cache_destroy(pool->sense_slab);
407 mutex_unlock(&host_cmd_pool_mutex);
411 * scsi_allocate_command - get a fully allocated SCSI command
412 * @gfp_mask: allocation mask
414 * This function is for use outside of the normal host based pools.
415 * It allocates the relevant command and takes an additional reference
416 * on the pool it used. This function *must* be paired with
417 * scsi_free_command which also has the identical mask, otherwise the
418 * free pool counts will eventually go wrong and you'll trigger a bug.
420 * This function should *only* be used by drivers that need a static
421 * command allocation at start of day for internal functions.
423 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
425 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
430 return scsi_pool_alloc_command(pool, gfp_mask);
432 EXPORT_SYMBOL(scsi_allocate_command);
435 * scsi_free_command - free a command allocated by scsi_allocate_command
436 * @gfp_mask: mask used in the original allocation
437 * @cmd: command to free
439 * Note: using the original allocation mask is vital because that's
440 * what determines which command pool we use to free the command. Any
441 * mismatch will cause the system to BUG eventually.
443 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
445 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
448 * this could trigger if the mask to scsi_allocate_command
449 * doesn't match this mask. Otherwise we're guaranteed that this
450 * succeeds because scsi_allocate_command must have taken a reference
455 scsi_pool_free_command(pool, cmd);
457 * scsi_put_host_cmd_pool is called twice; once to release the
458 * reference we took above, and once to release the reference
459 * originally taken by scsi_allocate_command
461 scsi_put_host_cmd_pool(gfp_mask);
462 scsi_put_host_cmd_pool(gfp_mask);
464 EXPORT_SYMBOL(scsi_free_command);
467 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
468 * @shost: host to allocate the freelist for.
470 * Description: The command freelist protects against system-wide out of memory
471 * deadlock by preallocating one SCSI command structure for each host, so the
472 * system can always write to a swap file on a device associated with that host.
476 int scsi_setup_command_freelist(struct Scsi_Host *shost)
478 struct scsi_cmnd *cmd;
479 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
481 spin_lock_init(&shost->free_list_lock);
482 INIT_LIST_HEAD(&shost->free_list);
484 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
486 if (!shost->cmd_pool)
490 * Get one backup command for this host.
492 cmd = scsi_host_alloc_command(shost, gfp_mask);
494 scsi_put_host_cmd_pool(gfp_mask);
495 shost->cmd_pool = NULL;
498 list_add(&cmd->list, &shost->free_list);
503 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
504 * @shost: host whose freelist is going to be destroyed
506 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
509 * If cmd_pool is NULL the free list was not initialized, so
510 * do not attempt to release resources.
512 if (!shost->cmd_pool)
515 while (!list_empty(&shost->free_list)) {
516 struct scsi_cmnd *cmd;
518 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
519 list_del_init(&cmd->list);
520 scsi_pool_free_command(shost->cmd_pool, cmd);
522 shost->cmd_pool = NULL;
523 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
526 #ifdef CONFIG_SCSI_LOGGING
527 void scsi_log_send(struct scsi_cmnd *cmd)
532 * If ML QUEUE log level is greater than or equal to:
534 * 1: nothing (match completion)
536 * 2: log opcode + command of all commands
538 * 3: same as 2 plus dump cmd address
540 * 4: same as 3 plus dump extra junk
542 if (unlikely(scsi_logging_level)) {
543 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
544 SCSI_LOG_MLQUEUE_BITS);
546 scmd_printk(KERN_INFO, cmd, "Send: ");
548 printk("0x%p ", cmd);
550 scsi_print_command(cmd);
552 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
553 " queuecommand 0x%p\n",
554 scsi_sglist(cmd), scsi_bufflen(cmd),
555 cmd->device->host->hostt->queuecommand);
562 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
567 * If ML COMPLETE log level is greater than or equal to:
569 * 1: log disposition, result, opcode + command, and conditionally
570 * sense data for failures or non SUCCESS dispositions.
572 * 2: same as 1 but for all command completions.
574 * 3: same as 2 plus dump cmd address
576 * 4: same as 3 plus dump extra junk
578 if (unlikely(scsi_logging_level)) {
579 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
580 SCSI_LOG_MLCOMPLETE_BITS);
581 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
583 scmd_printk(KERN_INFO, cmd, "Done: ");
585 printk("0x%p ", cmd);
587 * Dump truncated values, so we usually fit within
590 switch (disposition) {
605 * If called via scsi_times_out.
612 scsi_print_result(cmd);
613 scsi_print_command(cmd);
614 if (status_byte(cmd->result) & CHECK_CONDITION)
615 scsi_print_sense("", cmd);
617 scmd_printk(KERN_INFO, cmd,
618 "scsi host busy %d failed %d\n",
619 cmd->device->host->host_busy,
620 cmd->device->host->host_failed);
627 * scsi_cmd_get_serial - Assign a serial number to a command
628 * @host: the scsi host
629 * @cmd: command to assign serial number to
631 * Description: a serial number identifies a request for error recovery
632 * and debugging purposes. Protected by the Host_Lock of host.
634 static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
636 cmd->serial_number = host->cmd_serial_number++;
637 if (cmd->serial_number == 0)
638 cmd->serial_number = host->cmd_serial_number++;
642 * scsi_dispatch_command - Dispatch a command to the low-level driver.
643 * @cmd: command block we are dispatching.
645 * Return: nonzero return request was rejected and device's queue needs to be
648 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
650 struct Scsi_Host *host = cmd->device->host;
651 unsigned long flags = 0;
652 unsigned long timeout;
655 /* check if the device is still usable */
656 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
657 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
658 * returns an immediate error upwards, and signals
659 * that the device is no longer present */
660 cmd->result = DID_NO_CONNECT << 16;
661 atomic_inc(&cmd->device->iorequest_cnt);
663 /* return 0 (because the command has been processed) */
667 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
668 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
670 * in SDEV_BLOCK, the command is just put back on the device
671 * queue. The suspend state has already blocked the queue so
672 * future requests should not occur until the device
673 * transitions out of the suspend state.
675 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
677 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
680 * NOTE: rtn is still zero here because we don't need the
681 * queue to be plugged on return (it's already stopped)
687 * If SCSI-2 or lower, store the LUN value in cmnd.
689 if (cmd->device->scsi_level <= SCSI_2 &&
690 cmd->device->scsi_level != SCSI_UNKNOWN) {
691 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
692 (cmd->device->lun << 5 & 0xe0);
696 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
697 * we can avoid the drive not being ready.
699 timeout = host->last_reset + MIN_RESET_DELAY;
701 if (host->resetting && time_before(jiffies, timeout)) {
702 int ticks_remaining = timeout - jiffies;
704 * NOTE: This may be executed from within an interrupt
705 * handler! This is bad, but for now, it'll do. The irq
706 * level of the interrupt handler has been masked out by the
707 * platform dependent interrupt handling code already, so the
708 * sti() here will not cause another call to the SCSI host's
709 * interrupt handler (assuming there is one irq-level per
712 while (--ticks_remaining >= 0)
713 mdelay(1 + 999 / HZ);
718 * AK: unlikely race here: for some reason the timer could
719 * expire before the serial number is set up below.
721 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
726 * We will use a queued command if possible, otherwise we will
727 * emulate the queuing and calling of completion function ourselves.
729 atomic_inc(&cmd->device->iorequest_cnt);
732 * Before we queue this command, check if the command
733 * length exceeds what the host adapter can handle.
735 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
737 printk("queuecommand : command too long. "
738 "cdb_size=%d host->max_cmd_len=%d\n",
739 cmd->cmd_len, cmd->device->host->max_cmd_len));
740 cmd->result = (DID_ABORT << 16);
746 spin_lock_irqsave(host->host_lock, flags);
747 scsi_cmd_get_serial(host, cmd);
749 if (unlikely(host->shost_state == SHOST_DEL)) {
750 cmd->result = (DID_NO_CONNECT << 16);
753 rtn = host->hostt->queuecommand(cmd, scsi_done);
755 spin_unlock_irqrestore(host->host_lock, flags);
757 if (scsi_delete_timer(cmd)) {
758 atomic_inc(&cmd->device->iodone_cnt);
759 scsi_queue_insert(cmd,
760 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
761 rtn : SCSI_MLQUEUE_HOST_BUSY);
764 printk("queuecommand : request rejected\n"));
768 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
773 * scsi_req_abort_cmd -- Request command recovery for the specified command
774 * @cmd: pointer to the SCSI command of interest
776 * This function requests that SCSI Core start recovery for the
777 * command by deleting the timer and adding the command to the eh
778 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
779 * implement their own error recovery MAY ignore the timeout event if
780 * they generated scsi_req_abort_cmd.
782 void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
784 if (!scsi_delete_timer(cmd))
788 EXPORT_SYMBOL(scsi_req_abort_cmd);
791 * scsi_done - Enqueue the finished SCSI command into the done queue.
792 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
793 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
795 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
796 * which regains ownership of the SCSI command (de facto) from a LLDD, and
797 * enqueues the command to the done queue for further processing.
799 * This is the producer of the done queue who enqueues at the tail.
801 * This function is interrupt context safe.
803 static void scsi_done(struct scsi_cmnd *cmd)
806 * We don't have to worry about this one timing out anymore.
807 * If we are unable to remove the timer, then the command
808 * has already timed out. In which case, we have no choice but to
809 * let the timeout function run, as we have no idea where in fact
810 * that function could really be. It might be on another processor,
813 if (!scsi_delete_timer(cmd))
818 /* Private entry to scsi_done() to complete a command when the timer
819 * isn't running --- used by scsi_times_out */
820 void __scsi_done(struct scsi_cmnd *cmd)
822 struct request *rq = cmd->request;
825 * Set the serial numbers back to zero
827 cmd->serial_number = 0;
829 atomic_inc(&cmd->device->iodone_cnt);
831 atomic_inc(&cmd->device->ioerr_cnt);
836 * The uptodate/nbytes values don't matter, as we allow partial
837 * completes and thus will check this in the softirq callback
839 rq->completion_data = cmd;
840 blk_complete_request(rq);
843 /* Move this to a header if it becomes more generally useful */
844 static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
846 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
850 * scsi_finish_command - cleanup and pass command back to upper layer
853 * Description: Pass command off to upper layer for finishing of I/O
854 * request, waking processes that are waiting on results,
857 void scsi_finish_command(struct scsi_cmnd *cmd)
859 struct scsi_device *sdev = cmd->device;
860 struct Scsi_Host *shost = sdev->host;
861 struct scsi_driver *drv;
862 unsigned int good_bytes;
864 scsi_device_unbusy(sdev);
867 * Clear the flags which say that the device/host is no longer
868 * capable of accepting new commands. These are set in scsi_queue.c
869 * for both the queue full condition on a device, and for a
870 * host full condition on the host.
872 * XXX(hch): What about locking?
874 shost->host_blocked = 0;
875 sdev->device_blocked = 0;
878 * If we have valid sense information, then some kind of recovery
879 * must have taken place. Make a note of this.
881 if (SCSI_SENSE_VALID(cmd))
882 cmd->result |= (DRIVER_SENSE << 24);
884 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
885 "Notifying upper driver of completion "
886 "(result %x)\n", cmd->result));
888 good_bytes = scsi_bufflen(cmd);
889 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
890 int old_good_bytes = good_bytes;
891 drv = scsi_cmd_to_driver(cmd);
893 good_bytes = drv->done(cmd);
895 * USB may not give sense identifying bad sector and
896 * simply return a residue instead, so subtract off the
897 * residue if drv->done() error processing indicates no
898 * change to the completion length.
900 if (good_bytes == old_good_bytes)
901 good_bytes -= scsi_get_resid(cmd);
903 scsi_io_completion(cmd, good_bytes);
905 EXPORT_SYMBOL(scsi_finish_command);
908 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
909 * @sdev: SCSI Device in question
910 * @tagged: Do we use tagged queueing (non-0) or do we treat
911 * this device as an untagged device (0)
912 * @tags: Number of tags allowed if tagged queueing enabled,
913 * or number of commands the low level driver can
914 * queue up in non-tagged mode (as per cmd_per_lun).
918 * Lock Status: None held on entry
920 * Notes: Low level drivers may call this at any time and we will do
921 * the right thing depending on whether or not the device is
922 * currently active and whether or not it even has the
923 * command blocks built yet.
925 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
930 * refuse to set tagged depth to an unworkable size
935 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
938 * Check to see if the queue is managed by the block layer.
939 * If it is, and we fail to adjust the depth, exit.
941 * Do not resize the tag map if it is a host wide share bqt,
942 * because the size should be the hosts's can_queue. If there
943 * is more IO than the LLD's can_queue (so there are not enuogh
944 * tags) request_fn's host queue ready check will handle it.
946 if (!sdev->host->bqt) {
947 if (blk_queue_tagged(sdev->request_queue) &&
948 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
952 sdev->queue_depth = tags;
954 case MSG_ORDERED_TAG:
955 sdev->ordered_tags = 1;
956 sdev->simple_tags = 1;
959 sdev->ordered_tags = 0;
960 sdev->simple_tags = 1;
963 sdev_printk(KERN_WARNING, sdev,
964 "scsi_adjust_queue_depth, bad queue type, "
967 sdev->ordered_tags = sdev->simple_tags = 0;
968 sdev->queue_depth = tags;
972 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
974 EXPORT_SYMBOL(scsi_adjust_queue_depth);
977 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
978 * @sdev: SCSI Device in question
979 * @depth: Current number of outstanding SCSI commands on this device,
980 * not counting the one returned as QUEUE_FULL.
982 * Description: This function will track successive QUEUE_FULL events on a
983 * specific SCSI device to determine if and when there is a
984 * need to adjust the queue depth on the device.
986 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
987 * -1 - Drop back to untagged operation using host->cmd_per_lun
988 * as the untagged command depth
990 * Lock Status: None held on entry
992 * Notes: Low level drivers may call this at any time and we will do
993 * "The Right Thing." We are interrupt context safe.
995 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
997 if ((jiffies >> 4) == sdev->last_queue_full_time)
1000 sdev->last_queue_full_time = (jiffies >> 4);
1001 if (sdev->last_queue_full_depth != depth) {
1002 sdev->last_queue_full_count = 1;
1003 sdev->last_queue_full_depth = depth;
1005 sdev->last_queue_full_count++;
1008 if (sdev->last_queue_full_count <= 10)
1010 if (sdev->last_queue_full_depth < 8) {
1011 /* Drop back to untagged */
1012 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
1016 if (sdev->ordered_tags)
1017 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
1019 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
1022 EXPORT_SYMBOL(scsi_track_queue_full);
1025 * scsi_device_get - get an additional reference to a scsi_device
1026 * @sdev: device to get a reference to
1028 * Description: Gets a reference to the scsi_device and increments the use count
1029 * of the underlying LLDD module. You must hold host_lock of the
1030 * parent Scsi_Host or already have a reference when calling this.
1032 int scsi_device_get(struct scsi_device *sdev)
1034 if (sdev->sdev_state == SDEV_DEL)
1036 if (!get_device(&sdev->sdev_gendev))
1038 /* We can fail this if we're doing SCSI operations
1039 * from module exit (like cache flush) */
1040 try_module_get(sdev->host->hostt->module);
1044 EXPORT_SYMBOL(scsi_device_get);
1047 * scsi_device_put - release a reference to a scsi_device
1048 * @sdev: device to release a reference on.
1050 * Description: Release a reference to the scsi_device and decrements the use
1051 * count of the underlying LLDD module. The device is freed once the last
1054 void scsi_device_put(struct scsi_device *sdev)
1056 #ifdef CONFIG_MODULE_UNLOAD
1057 struct module *module = sdev->host->hostt->module;
1059 /* The module refcount will be zero if scsi_device_get()
1060 * was called from a module removal routine */
1061 if (module && module_refcount(module) != 0)
1064 put_device(&sdev->sdev_gendev);
1066 EXPORT_SYMBOL(scsi_device_put);
1068 /* helper for shost_for_each_device, see that for documentation */
1069 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1070 struct scsi_device *prev)
1072 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1073 struct scsi_device *next = NULL;
1074 unsigned long flags;
1076 spin_lock_irqsave(shost->host_lock, flags);
1077 while (list->next != &shost->__devices) {
1078 next = list_entry(list->next, struct scsi_device, siblings);
1079 /* skip devices that we can't get a reference to */
1080 if (!scsi_device_get(next))
1085 spin_unlock_irqrestore(shost->host_lock, flags);
1088 scsi_device_put(prev);
1091 EXPORT_SYMBOL(__scsi_iterate_devices);
1094 * starget_for_each_device - helper to walk all devices of a target
1095 * @starget: target whose devices we want to iterate over.
1096 * @data: Opaque passed to each function call.
1097 * @fn: Function to call on each device
1099 * This traverses over each device of @starget. The devices have
1100 * a reference that must be released by scsi_host_put when breaking
1103 void starget_for_each_device(struct scsi_target *starget, void *data,
1104 void (*fn)(struct scsi_device *, void *))
1106 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1107 struct scsi_device *sdev;
1109 shost_for_each_device(sdev, shost) {
1110 if ((sdev->channel == starget->channel) &&
1111 (sdev->id == starget->id))
1115 EXPORT_SYMBOL(starget_for_each_device);
1118 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1119 * @starget: target whose devices we want to iterate over.
1120 * @data: parameter for callback @fn()
1121 * @fn: callback function that is invoked for each device
1123 * This traverses over each device of @starget. It does _not_
1124 * take a reference on the scsi_device, so the whole loop must be
1125 * protected by shost->host_lock.
1127 * Note: The only reason why drivers would want to use this is because
1128 * they need to access the device list in irq context. Otherwise you
1129 * really want to use starget_for_each_device instead.
1131 void __starget_for_each_device(struct scsi_target *starget, void *data,
1132 void (*fn)(struct scsi_device *, void *))
1134 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1135 struct scsi_device *sdev;
1137 __shost_for_each_device(sdev, shost) {
1138 if ((sdev->channel == starget->channel) &&
1139 (sdev->id == starget->id))
1143 EXPORT_SYMBOL(__starget_for_each_device);
1146 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1147 * @starget: SCSI target pointer
1148 * @lun: SCSI Logical Unit Number
1150 * Description: Looks up the scsi_device with the specified @lun for a given
1151 * @starget. The returned scsi_device does not have an additional
1152 * reference. You must hold the host's host_lock over this call and
1153 * any access to the returned scsi_device.
1155 * Note: The only reason why drivers should use this is because
1156 * they need to access the device list in irq context. Otherwise you
1157 * really want to use scsi_device_lookup_by_target instead.
1159 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1162 struct scsi_device *sdev;
1164 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1165 if (sdev->lun ==lun)
1171 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1174 * scsi_device_lookup_by_target - find a device given the target
1175 * @starget: SCSI target pointer
1176 * @lun: SCSI Logical Unit Number
1178 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1179 * for a given host. The returned scsi_device has an additional reference that
1180 * needs to be released with scsi_device_put once you're done with it.
1182 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1185 struct scsi_device *sdev;
1186 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1187 unsigned long flags;
1189 spin_lock_irqsave(shost->host_lock, flags);
1190 sdev = __scsi_device_lookup_by_target(starget, lun);
1191 if (sdev && scsi_device_get(sdev))
1193 spin_unlock_irqrestore(shost->host_lock, flags);
1197 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1200 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1201 * @shost: SCSI host pointer
1202 * @channel: SCSI channel (zero if only one channel)
1203 * @id: SCSI target number (physical unit number)
1204 * @lun: SCSI Logical Unit Number
1206 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1207 * for a given host. The returned scsi_device does not have an additional
1208 * reference. You must hold the host's host_lock over this call and any access
1209 * to the returned scsi_device.
1211 * Note: The only reason why drivers would want to use this is because
1212 * they need to access the device list in irq context. Otherwise you
1213 * really want to use scsi_device_lookup instead.
1215 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1216 uint channel, uint id, uint lun)
1218 struct scsi_device *sdev;
1220 list_for_each_entry(sdev, &shost->__devices, siblings) {
1221 if (sdev->channel == channel && sdev->id == id &&
1228 EXPORT_SYMBOL(__scsi_device_lookup);
1231 * scsi_device_lookup - find a device given the host
1232 * @shost: SCSI host pointer
1233 * @channel: SCSI channel (zero if only one channel)
1234 * @id: SCSI target number (physical unit number)
1235 * @lun: SCSI Logical Unit Number
1237 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1238 * for a given host. The returned scsi_device has an additional reference that
1239 * needs to be released with scsi_device_put once you're done with it.
1241 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1242 uint channel, uint id, uint lun)
1244 struct scsi_device *sdev;
1245 unsigned long flags;
1247 spin_lock_irqsave(shost->host_lock, flags);
1248 sdev = __scsi_device_lookup(shost, channel, id, lun);
1249 if (sdev && scsi_device_get(sdev))
1251 spin_unlock_irqrestore(shost->host_lock, flags);
1255 EXPORT_SYMBOL(scsi_device_lookup);
1257 MODULE_DESCRIPTION("SCSI core");
1258 MODULE_LICENSE("GPL");
1260 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1261 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1263 static int __init init_scsi(void)
1267 error = scsi_init_queue();
1270 error = scsi_init_procfs();
1273 error = scsi_init_devinfo();
1275 goto cleanup_procfs;
1276 error = scsi_init_hosts();
1278 goto cleanup_devlist;
1279 error = scsi_init_sysctl();
1282 error = scsi_sysfs_register();
1284 goto cleanup_sysctl;
1286 scsi_netlink_init();
1288 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1296 scsi_exit_devinfo();
1301 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1306 static void __exit exit_scsi(void)
1308 scsi_netlink_exit();
1309 scsi_sysfs_unregister();
1312 scsi_exit_devinfo();
1317 subsys_initcall(init_scsi);
1318 module_exit(exit_scsi);