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/sched.h>
44 #include <linux/timer.h>
45 #include <linux/string.h>
46 #include <linux/slab.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/init.h>
50 #include <linux/completion.h>
51 #include <linux/devfs_fs_kernel.h>
52 #include <linux/unistd.h>
53 #include <linux/spinlock.h>
54 #include <linux/kmod.h>
55 #include <linux/interrupt.h>
56 #include <linux/notifier.h>
57 #include <linux/cpu.h>
59 #include <scsi/scsi.h>
60 #include <scsi/scsi_cmnd.h>
61 #include <scsi/scsi_dbg.h>
62 #include <scsi/scsi_device.h>
63 #include <scsi/scsi_eh.h>
64 #include <scsi/scsi_host.h>
65 #include <scsi/scsi_tcq.h>
66 #include <scsi/scsi_request.h>
68 #include "scsi_priv.h"
69 #include "scsi_logging.h"
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 * Macro to determine the size of SCSI command. This macro takes vendor
83 * unique commands into account. SCSI commands in groups 6 and 7 are
84 * vendor unique and we will depend upon the command length being
85 * supplied correctly in cmd_len.
87 #define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
88 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
93 unsigned long scsi_pid;
94 static unsigned long serial_number;
97 * Note - the initial logging level can be set here to log events at boot time.
98 * After the system is up, you may enable logging via the /proc interface.
100 unsigned int scsi_logging_level;
101 #if defined(CONFIG_SCSI_LOGGING)
102 EXPORT_SYMBOL(scsi_logging_level);
105 const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] = {
121 EXPORT_SYMBOL(scsi_device_types);
124 * Function: scsi_allocate_request
126 * Purpose: Allocate a request descriptor.
128 * Arguments: device - device for which we want a request
129 * gfp_mask - allocation flags passed to kmalloc
131 * Lock status: No locks assumed to be held. This function is SMP-safe.
133 * Returns: Pointer to request block.
135 struct scsi_request *scsi_allocate_request(struct scsi_device *sdev,
138 const int offset = ALIGN(sizeof(struct scsi_request), 4);
139 const int size = offset + sizeof(struct request);
140 struct scsi_request *sreq;
142 sreq = kmalloc(size, gfp_mask);
143 if (likely(sreq != NULL)) {
144 memset(sreq, 0, size);
145 sreq->sr_request = (struct request *)(((char *)sreq) + offset);
146 sreq->sr_device = sdev;
147 sreq->sr_host = sdev->host;
148 sreq->sr_magic = SCSI_REQ_MAGIC;
149 sreq->sr_data_direction = DMA_BIDIRECTIONAL;
154 EXPORT_SYMBOL(scsi_allocate_request);
156 void __scsi_release_request(struct scsi_request *sreq)
158 struct request *req = sreq->sr_request;
160 /* unlikely because the tag was usually ended earlier by the
161 * mid-layer. However, for layering reasons ULD's don't end
162 * the tag of commands they generate. */
163 if (unlikely(blk_rq_tagged(req))) {
165 struct request_queue *q = req->q;
167 spin_lock_irqsave(q->queue_lock, flags);
168 blk_queue_end_tag(q, req);
169 spin_unlock_irqrestore(q->queue_lock, flags);
173 if (likely(sreq->sr_command != NULL)) {
174 struct scsi_cmnd *cmd = sreq->sr_command;
176 sreq->sr_command = NULL;
177 scsi_next_command(cmd);
182 * Function: scsi_release_request
184 * Purpose: Release a request descriptor.
186 * Arguments: sreq - request to release
188 * Lock status: No locks assumed to be held. This function is SMP-safe.
190 void scsi_release_request(struct scsi_request *sreq)
192 __scsi_release_request(sreq);
195 EXPORT_SYMBOL(scsi_release_request);
197 struct scsi_host_cmd_pool {
201 unsigned int slab_flags;
202 unsigned int gfp_mask;
205 static struct scsi_host_cmd_pool scsi_cmd_pool = {
206 .name = "scsi_cmd_cache",
207 .slab_flags = SLAB_HWCACHE_ALIGN,
210 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
211 .name = "scsi_cmd_cache(DMA)",
212 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
213 .gfp_mask = __GFP_DMA,
216 static DECLARE_MUTEX(host_cmd_pool_mutex);
218 static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost,
221 struct scsi_cmnd *cmd;
223 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
224 gfp_mask | shost->cmd_pool->gfp_mask);
226 if (unlikely(!cmd)) {
229 spin_lock_irqsave(&shost->free_list_lock, flags);
230 if (likely(!list_empty(&shost->free_list))) {
231 cmd = list_entry(shost->free_list.next,
232 struct scsi_cmnd, list);
233 list_del_init(&cmd->list);
235 spin_unlock_irqrestore(&shost->free_list_lock, flags);
242 * Function: scsi_get_command()
244 * Purpose: Allocate and setup a scsi command block
246 * Arguments: dev - parent scsi device
247 * gfp_mask- allocator flags
249 * Returns: The allocated scsi command structure.
251 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, int gfp_mask)
253 struct scsi_cmnd *cmd;
255 /* Bail if we can't get a reference to the device */
256 if (!get_device(&dev->sdev_gendev))
259 cmd = __scsi_get_command(dev->host, gfp_mask);
261 if (likely(cmd != NULL)) {
264 memset(cmd, 0, sizeof(*cmd));
266 cmd->state = SCSI_STATE_UNUSED;
267 cmd->owner = SCSI_OWNER_NOBODY;
268 init_timer(&cmd->eh_timeout);
269 INIT_LIST_HEAD(&cmd->list);
270 spin_lock_irqsave(&dev->list_lock, flags);
271 list_add_tail(&cmd->list, &dev->cmd_list);
272 spin_unlock_irqrestore(&dev->list_lock, flags);
274 put_device(&dev->sdev_gendev);
278 EXPORT_SYMBOL(scsi_get_command);
281 * Function: scsi_put_command()
283 * Purpose: Free a scsi command block
285 * Arguments: cmd - command block to free
289 * Notes: The command must not belong to any lists.
291 void scsi_put_command(struct scsi_cmnd *cmd)
293 struct scsi_device *sdev = cmd->device;
294 struct Scsi_Host *shost = sdev->host;
297 /* serious error if the command hasn't come from a device list */
298 spin_lock_irqsave(&cmd->device->list_lock, flags);
299 BUG_ON(list_empty(&cmd->list));
300 list_del_init(&cmd->list);
301 spin_unlock(&cmd->device->list_lock);
302 /* changing locks here, don't need to restore the irq state */
303 spin_lock(&shost->free_list_lock);
304 if (unlikely(list_empty(&shost->free_list))) {
305 list_add(&cmd->list, &shost->free_list);
308 spin_unlock_irqrestore(&shost->free_list_lock, flags);
310 if (likely(cmd != NULL))
311 kmem_cache_free(shost->cmd_pool->slab, cmd);
313 put_device(&sdev->sdev_gendev);
315 EXPORT_SYMBOL(scsi_put_command);
318 * Function: scsi_setup_command_freelist()
320 * Purpose: Setup the command freelist for a scsi host.
322 * Arguments: shost - host to allocate the freelist for.
326 int scsi_setup_command_freelist(struct Scsi_Host *shost)
328 struct scsi_host_cmd_pool *pool;
329 struct scsi_cmnd *cmd;
331 spin_lock_init(&shost->free_list_lock);
332 INIT_LIST_HEAD(&shost->free_list);
335 * Select a command slab for this host and create it if not
338 down(&host_cmd_pool_mutex);
339 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
341 pool->slab = kmem_cache_create(pool->name,
342 sizeof(struct scsi_cmnd), 0,
343 pool->slab_flags, NULL, NULL);
349 shost->cmd_pool = pool;
350 up(&host_cmd_pool_mutex);
353 * Get one backup command for this host.
355 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
356 GFP_KERNEL | shost->cmd_pool->gfp_mask);
359 list_add(&cmd->list, &shost->free_list);
364 kmem_cache_destroy(pool->slab);
367 up(&host_cmd_pool_mutex);
373 * Function: scsi_destroy_command_freelist()
375 * Purpose: Release the command freelist for a scsi host.
377 * Arguments: shost - host that's freelist is going to be destroyed
379 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
381 while (!list_empty(&shost->free_list)) {
382 struct scsi_cmnd *cmd;
384 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
385 list_del_init(&cmd->list);
386 kmem_cache_free(shost->cmd_pool->slab, cmd);
389 down(&host_cmd_pool_mutex);
390 if (!--shost->cmd_pool->users)
391 kmem_cache_destroy(shost->cmd_pool->slab);
392 up(&host_cmd_pool_mutex);
395 #ifdef CONFIG_SCSI_LOGGING
396 void scsi_log_send(struct scsi_cmnd *cmd)
399 struct scsi_device *sdev;
402 * If ML QUEUE log level is greater than or equal to:
404 * 1: nothing (match completion)
406 * 2: log opcode + command of all commands
408 * 3: same as 2 plus dump cmd address
410 * 4: same as 3 plus dump extra junk
412 if (unlikely(scsi_logging_level)) {
413 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
414 SCSI_LOG_MLQUEUE_BITS);
417 printk(KERN_INFO "scsi <%d:%d:%d:%d> send ",
418 sdev->host->host_no, sdev->channel, sdev->id,
421 printk("0x%p ", cmd);
423 * spaces to match disposition and cmd->result
424 * output in scsi_log_completion.
427 scsi_print_command(cmd);
429 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
430 " done = 0x%p, queuecommand 0x%p\n",
431 cmd->buffer, cmd->bufflen,
433 sdev->host->hostt->queuecommand);
440 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
443 struct scsi_device *sdev;
446 * If ML COMPLETE log level is greater than or equal to:
448 * 1: log disposition, result, opcode + command, and conditionally
449 * sense data for failures or non SUCCESS dispositions.
451 * 2: same as 1 but for all command completions.
453 * 3: same as 2 plus dump cmd address
455 * 4: same as 3 plus dump extra junk
457 if (unlikely(scsi_logging_level)) {
458 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
459 SCSI_LOG_MLCOMPLETE_BITS);
460 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
463 printk(KERN_INFO "scsi <%d:%d:%d:%d> done ",
464 sdev->host->host_no, sdev->channel, sdev->id,
467 printk("0x%p ", cmd);
469 * Dump truncated values, so we usually fit within
472 switch (disposition) {
487 * If called via scsi_times_out.
494 printk(" %8x ", cmd->result);
495 scsi_print_command(cmd);
496 if (status_byte(cmd->result) & CHECK_CONDITION) {
498 * XXX The print_sense formatting/prefix
499 * doesn't match this function.
501 scsi_print_sense("", cmd);
504 printk(KERN_INFO "scsi host busy %d failed %d\n",
505 sdev->host->host_busy,
506 sdev->host->host_failed);
514 * Function: scsi_dispatch_command
516 * Purpose: Dispatch a command to the low-level driver.
518 * Arguments: cmd - command block we are dispatching.
522 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
524 struct Scsi_Host *host = cmd->device->host;
525 unsigned long flags = 0;
526 unsigned long timeout;
529 /* check if the device is still usable */
530 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
531 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
532 * returns an immediate error upwards, and signals
533 * that the device is no longer present */
534 cmd->result = DID_NO_CONNECT << 16;
536 /* return 0 (because the command has been processed) */
540 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
541 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
543 * in SDEV_BLOCK, the command is just put back on the device
544 * queue. The suspend state has already blocked the queue so
545 * future requests should not occur until the device
546 * transitions out of the suspend state.
548 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
550 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
553 * NOTE: rtn is still zero here because we don't need the
554 * queue to be plugged on return (it's already stopped)
559 /* Assign a unique nonzero serial_number. */
560 /* XXX(hch): this is racy */
561 if (++serial_number == 0)
563 cmd->serial_number = serial_number;
564 cmd->pid = scsi_pid++;
567 * If SCSI-2 or lower, store the LUN value in cmnd.
569 if (cmd->device->scsi_level <= SCSI_2) {
570 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
571 (cmd->device->lun << 5 & 0xe0);
575 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
576 * we can avoid the drive not being ready.
578 timeout = host->last_reset + MIN_RESET_DELAY;
580 if (host->resetting && time_before(jiffies, timeout)) {
581 int ticks_remaining = timeout - jiffies;
583 * NOTE: This may be executed from within an interrupt
584 * handler! This is bad, but for now, it'll do. The irq
585 * level of the interrupt handler has been masked out by the
586 * platform dependent interrupt handling code already, so the
587 * sti() here will not cause another call to the SCSI host's
588 * interrupt handler (assuming there is one irq-level per
591 while (--ticks_remaining >= 0)
592 mdelay(1 + 999 / HZ);
596 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
601 * We will use a queued command if possible, otherwise we will
602 * emulate the queuing and calling of completion function ourselves.
605 cmd->state = SCSI_STATE_QUEUED;
606 cmd->owner = SCSI_OWNER_LOWLEVEL;
609 * Before we queue this command, check if the command
610 * length exceeds what the host adapter can handle.
612 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
614 printk("queuecommand : command too long.\n"));
615 cmd->result = (DID_ABORT << 16);
621 spin_lock_irqsave(host->host_lock, flags);
622 if (unlikely(test_bit(SHOST_CANCEL, &host->shost_state))) {
623 cmd->result = (DID_NO_CONNECT << 16);
626 rtn = host->hostt->queuecommand(cmd, scsi_done);
628 spin_unlock_irqrestore(host->host_lock, flags);
630 scsi_queue_insert(cmd,
631 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
632 rtn : SCSI_MLQUEUE_HOST_BUSY);
634 printk("queuecommand : request rejected\n"));
638 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
643 * Function: scsi_init_cmd_from_req
645 * Purpose: Queue a SCSI command
646 * Purpose: Initialize a struct scsi_cmnd from a struct scsi_request
648 * Arguments: cmd - command descriptor.
649 * sreq - Request from the queue.
651 * Lock status: None needed.
655 * Notes: Mainly transfer data from the request structure to the
656 * command structure. The request structure is allocated
657 * using the normal memory allocator, and requests can pile
658 * up to more or less any depth. The command structure represents
659 * a consumable resource, as these are allocated into a pool
660 * when the SCSI subsystem initializes. The preallocation is
661 * required so that in low-memory situations a disk I/O request
662 * won't cause the memory manager to try and write out a page.
663 * The request structure is generally used by ioctls and character
666 void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq)
668 sreq->sr_command = cmd;
670 cmd->owner = SCSI_OWNER_MIDLEVEL;
671 cmd->cmd_len = sreq->sr_cmd_len;
672 cmd->use_sg = sreq->sr_use_sg;
674 cmd->request = sreq->sr_request;
675 memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd));
676 cmd->serial_number = 0;
677 cmd->serial_number_at_timeout = 0;
678 cmd->bufflen = sreq->sr_bufflen;
679 cmd->buffer = sreq->sr_buffer;
681 cmd->allowed = sreq->sr_allowed;
682 cmd->done = sreq->sr_done;
683 cmd->timeout_per_command = sreq->sr_timeout_per_command;
684 cmd->sc_data_direction = sreq->sr_data_direction;
685 cmd->sglist_len = sreq->sr_sglist_len;
686 cmd->underflow = sreq->sr_underflow;
687 cmd->sc_request = sreq;
688 memcpy(cmd->cmnd, sreq->sr_cmnd, sizeof(sreq->sr_cmnd));
691 * Zero the sense buffer. Some host adapters automatically request
692 * sense on error. 0 is not a valid sense code.
694 memset(cmd->sense_buffer, 0, sizeof(sreq->sr_sense_buffer));
695 cmd->request_buffer = sreq->sr_buffer;
696 cmd->request_bufflen = sreq->sr_bufflen;
697 cmd->old_use_sg = cmd->use_sg;
698 if (cmd->cmd_len == 0)
699 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
700 cmd->old_cmd_len = cmd->cmd_len;
701 cmd->sc_old_data_direction = cmd->sc_data_direction;
702 cmd->old_underflow = cmd->underflow;
705 * Start the timer ticking.
707 cmd->internal_timeout = NORMAL_TIMEOUT;
708 cmd->abort_reason = 0;
711 SCSI_LOG_MLQUEUE(3, printk("Leaving scsi_init_cmd_from_req()\n"));
715 * Per-CPU I/O completion queue.
717 static DEFINE_PER_CPU(struct list_head, scsi_done_q);
720 * scsi_done - Enqueue the finished SCSI command into the done queue.
721 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
722 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
724 * This function is the mid-level's (SCSI Core) interrupt routine, which
725 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
726 * the command to the done queue for further processing.
728 * This is the producer of the done queue who enqueues at the tail.
730 * This function is interrupt context safe.
732 void scsi_done(struct scsi_cmnd *cmd)
735 * We don't have to worry about this one timing out any more.
736 * If we are unable to remove the timer, then the command
737 * has already timed out. In which case, we have no choice but to
738 * let the timeout function run, as we have no idea where in fact
739 * that function could really be. It might be on another processor,
742 if (!scsi_delete_timer(cmd))
747 /* Private entry to scsi_done() to complete a command when the timer
748 * isn't running --- used by scsi_times_out */
749 void __scsi_done(struct scsi_cmnd *cmd)
754 * Set the serial numbers back to zero
756 cmd->serial_number = 0;
757 cmd->serial_number_at_timeout = 0;
758 cmd->state = SCSI_STATE_BHQUEUE;
759 cmd->owner = SCSI_OWNER_BH_HANDLER;
762 * Next, enqueue the command into the done queue.
763 * It is a per-CPU queue, so we just disable local interrupts
764 * and need no spinlock.
766 local_irq_save(flags);
767 list_add_tail(&cmd->eh_entry, &__get_cpu_var(scsi_done_q));
768 raise_softirq_irqoff(SCSI_SOFTIRQ);
769 local_irq_restore(flags);
773 * scsi_softirq - Perform post-interrupt processing of finished SCSI commands.
775 * This is the consumer of the done queue.
777 * This is called with all interrupts enabled. This should reduce
778 * interrupt latency, stack depth, and reentrancy of the low-level
781 static void scsi_softirq(struct softirq_action *h)
787 list_splice_init(&__get_cpu_var(scsi_done_q), &local_q);
790 while (!list_empty(&local_q)) {
791 struct scsi_cmnd *cmd = list_entry(local_q.next,
792 struct scsi_cmnd, eh_entry);
793 list_del_init(&cmd->eh_entry);
795 disposition = scsi_decide_disposition(cmd);
796 scsi_log_completion(cmd, disposition);
797 switch (disposition) {
799 scsi_finish_command(cmd);
802 scsi_retry_command(cmd);
805 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
808 if (!scsi_eh_scmd_add(cmd, 0))
809 scsi_finish_command(cmd);
815 * Function: scsi_retry_command
817 * Purpose: Send a command back to the low level to be retried.
819 * Notes: This command is always executed in the context of the
820 * bottom half handler, or the error handler thread. Low
821 * level drivers should not become re-entrant as a result of
824 int scsi_retry_command(struct scsi_cmnd *cmd)
827 * Restore the SCSI command state.
829 scsi_setup_cmd_retry(cmd);
832 * Zero the sense information from the last time we tried
835 memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
837 return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
841 * Function: scsi_finish_command
843 * Purpose: Pass command off to upper layer for finishing of I/O
844 * request, waking processes that are waiting on results,
847 void scsi_finish_command(struct scsi_cmnd *cmd)
849 struct scsi_device *sdev = cmd->device;
850 struct Scsi_Host *shost = sdev->host;
851 struct scsi_request *sreq;
853 scsi_device_unbusy(sdev);
856 * Clear the flags which say that the device/host is no longer
857 * capable of accepting new commands. These are set in scsi_queue.c
858 * for both the queue full condition on a device, and for a
859 * host full condition on the host.
861 * XXX(hch): What about locking?
863 shost->host_blocked = 0;
864 sdev->device_blocked = 0;
867 * If we have valid sense information, then some kind of recovery
868 * must have taken place. Make a note of this.
870 if (SCSI_SENSE_VALID(cmd))
871 cmd->result |= (DRIVER_SENSE << 24);
873 SCSI_LOG_MLCOMPLETE(4, printk("Notifying upper driver of completion "
874 "for device %d %x\n", sdev->id, cmd->result));
876 cmd->owner = SCSI_OWNER_HIGHLEVEL;
877 cmd->state = SCSI_STATE_FINISHED;
880 * We can get here with use_sg=0, causing a panic in the upper level
882 cmd->use_sg = cmd->old_use_sg;
885 * If there is an associated request structure, copy the data over
886 * before we call the completion function.
888 sreq = cmd->sc_request;
890 sreq->sr_result = sreq->sr_command->result;
891 if (sreq->sr_result) {
892 memcpy(sreq->sr_sense_buffer,
893 sreq->sr_command->sense_buffer,
894 sizeof(sreq->sr_sense_buffer));
900 EXPORT_SYMBOL(scsi_finish_command);
903 * Function: scsi_adjust_queue_depth()
905 * Purpose: Allow low level drivers to tell us to change the queue depth
906 * on a specific SCSI device
908 * Arguments: sdev - SCSI Device in question
909 * tagged - Do we use tagged queueing (non-0) or do we treat
910 * this device as an untagged device (0)
911 * tags - Number of tags allowed if tagged queueing enabled,
912 * or number of commands the low level driver can
913 * queue up in non-tagged mode (as per cmd_per_lun).
917 * Lock Status: None held on entry
919 * Notes: Low level drivers may call this at any time and we will do
920 * the right thing depending on whether or not the device is
921 * currently active and whether or not it even has the
922 * command blocks built yet.
924 * XXX(hch): What exactly is device_request_lock trying to protect?
926 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
928 static DEFINE_SPINLOCK(device_request_lock);
932 * refuse to set tagged depth to an unworkable size
937 spin_lock_irqsave(&device_request_lock, flags);
938 spin_lock(sdev->request_queue->queue_lock);
940 /* Check to see if the queue is managed by the block layer
941 * if it is, and we fail to adjust the depth, exit */
942 if (blk_queue_tagged(sdev->request_queue) &&
943 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
946 sdev->queue_depth = tags;
948 case MSG_ORDERED_TAG:
949 sdev->ordered_tags = 1;
950 sdev->simple_tags = 1;
953 sdev->ordered_tags = 0;
954 sdev->simple_tags = 1;
957 printk(KERN_WARNING "(scsi%d:%d:%d:%d) "
958 "scsi_adjust_queue_depth, bad queue type, "
959 "disabled\n", sdev->host->host_no,
960 sdev->channel, sdev->id, sdev->lun);
962 sdev->ordered_tags = sdev->simple_tags = 0;
963 sdev->queue_depth = tags;
967 spin_unlock(sdev->request_queue->queue_lock);
968 spin_unlock_irqrestore(&device_request_lock, flags);
970 EXPORT_SYMBOL(scsi_adjust_queue_depth);
973 * Function: scsi_track_queue_full()
975 * Purpose: This function will track successive QUEUE_FULL events on a
976 * specific SCSI device to determine if and when there is a
977 * need to adjust the queue depth on the device.
979 * Arguments: sdev - SCSI Device in question
980 * depth - Current number of outstanding SCSI commands on
981 * this device, not counting the one returned as
984 * Returns: 0 - No change needed
985 * >0 - Adjust queue depth to this new depth
986 * -1 - Drop back to untagged operation using host->cmd_per_lun
987 * as the untagged command depth
989 * Lock Status: None held on entry
991 * Notes: Low level drivers may call this at any time and we will do
992 * "The Right Thing." We are interrupt context safe.
994 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
996 if ((jiffies >> 4) == sdev->last_queue_full_time)
999 sdev->last_queue_full_time = (jiffies >> 4);
1000 if (sdev->last_queue_full_depth != depth) {
1001 sdev->last_queue_full_count = 1;
1002 sdev->last_queue_full_depth = depth;
1004 sdev->last_queue_full_count++;
1007 if (sdev->last_queue_full_count <= 10)
1009 if (sdev->last_queue_full_depth < 8) {
1010 /* Drop back to untagged */
1011 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
1015 if (sdev->ordered_tags)
1016 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
1018 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
1021 EXPORT_SYMBOL(scsi_track_queue_full);
1024 * scsi_device_get - get an addition reference to a scsi_device
1025 * @sdev: device to get a reference to
1027 * Gets a reference to the scsi_device and increments the use count
1028 * of the underlying LLDD module. You must hold host_lock of the
1029 * parent Scsi_Host or already have a reference when calling this.
1031 int scsi_device_get(struct scsi_device *sdev)
1033 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
1035 if (!get_device(&sdev->sdev_gendev))
1037 if (!try_module_get(sdev->host->hostt->module)) {
1038 put_device(&sdev->sdev_gendev);
1043 EXPORT_SYMBOL(scsi_device_get);
1046 * scsi_device_put - release a reference to a scsi_device
1047 * @sdev: device to release a reference on.
1049 * Release a reference to the scsi_device and decrements the use count
1050 * of the underlying LLDD module. The device is freed once the last
1053 void scsi_device_put(struct scsi_device *sdev)
1055 module_put(sdev->host->hostt->module);
1056 put_device(&sdev->sdev_gendev);
1058 EXPORT_SYMBOL(scsi_device_put);
1060 /* helper for shost_for_each_device, thus not documented */
1061 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1062 struct scsi_device *prev)
1064 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1065 struct scsi_device *next = NULL;
1066 unsigned long flags;
1068 spin_lock_irqsave(shost->host_lock, flags);
1069 while (list->next != &shost->__devices) {
1070 next = list_entry(list->next, struct scsi_device, siblings);
1071 /* skip devices that we can't get a reference to */
1072 if (!scsi_device_get(next))
1077 spin_unlock_irqrestore(shost->host_lock, flags);
1080 scsi_device_put(prev);
1083 EXPORT_SYMBOL(__scsi_iterate_devices);
1086 * starget_for_each_device - helper to walk all devices of a target
1087 * @starget: target whose devices we want to iterate over.
1089 * This traverses over each devices of @shost. The devices have
1090 * a reference that must be released by scsi_host_put when breaking
1093 void starget_for_each_device(struct scsi_target *starget, void * data,
1094 void (*fn)(struct scsi_device *, void *))
1096 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1097 struct scsi_device *sdev;
1099 shost_for_each_device(sdev, shost) {
1100 if ((sdev->channel == starget->channel) &&
1101 (sdev->id == starget->id))
1105 EXPORT_SYMBOL(starget_for_each_device);
1108 * scsi_device_lookup - find a device given the host (UNLOCKED)
1109 * @shost: SCSI host pointer
1110 * @channel: SCSI channel (zero if only one channel)
1111 * @pun: SCSI target number (physical unit number)
1112 * @lun: SCSI Logical Unit Number
1114 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1115 * give host. The returned scsi_device does not have an additional reference.
1116 * You must hold the host's host_lock over this call and any access to the
1117 * returned scsi_device.
1119 * Note: The only reason why drivers would want to use this is because
1120 * they're need to access the device list in irq context. Otherwise you
1121 * really want to use scsi_device_lookup instead.
1123 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1124 uint channel, uint id, uint lun)
1126 struct scsi_device *sdev;
1128 list_for_each_entry(sdev, &shost->__devices, siblings) {
1129 if (sdev->channel == channel && sdev->id == id &&
1136 EXPORT_SYMBOL(__scsi_device_lookup);
1139 * scsi_device_lookup - find a device given the host
1140 * @shost: SCSI host pointer
1141 * @channel: SCSI channel (zero if only one channel)
1142 * @id: SCSI target number (physical unit number)
1143 * @lun: SCSI Logical Unit Number
1145 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1146 * give host. The returned scsi_device has an additional reference that
1147 * needs to be release with scsi_host_put once you're done with it.
1149 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1150 uint channel, uint id, uint lun)
1152 struct scsi_device *sdev;
1153 unsigned long flags;
1155 spin_lock_irqsave(shost->host_lock, flags);
1156 sdev = __scsi_device_lookup(shost, channel, id, lun);
1157 if (sdev && scsi_device_get(sdev))
1159 spin_unlock_irqrestore(shost->host_lock, flags);
1163 EXPORT_SYMBOL(scsi_device_lookup);
1166 * scsi_device_cancel - cancel outstanding IO to this device
1167 * @sdev: Pointer to struct scsi_device
1168 * @recovery: Boolean instructing function to recover device or not.
1171 int scsi_device_cancel(struct scsi_device *sdev, int recovery)
1173 struct scsi_cmnd *scmd;
1174 LIST_HEAD(active_list);
1175 struct list_head *lh, *lh_sf;
1176 unsigned long flags;
1178 scsi_device_set_state(sdev, SDEV_CANCEL);
1180 spin_lock_irqsave(&sdev->list_lock, flags);
1181 list_for_each_entry(scmd, &sdev->cmd_list, list) {
1182 if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) {
1184 * If we are unable to remove the timer, it means
1185 * that the command has already timed out or
1188 if (!scsi_delete_timer(scmd))
1190 list_add_tail(&scmd->eh_entry, &active_list);
1193 spin_unlock_irqrestore(&sdev->list_lock, flags);
1195 if (!list_empty(&active_list)) {
1196 list_for_each_safe(lh, lh_sf, &active_list) {
1197 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1200 scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
1202 scmd->result = (DID_ABORT << 16);
1203 scsi_finish_command(scmd);
1210 EXPORT_SYMBOL(scsi_device_cancel);
1212 #ifdef CONFIG_HOTPLUG_CPU
1213 static int scsi_cpu_notify(struct notifier_block *self,
1214 unsigned long action, void *hcpu)
1216 int cpu = (unsigned long)hcpu;
1220 /* Drain scsi_done_q. */
1221 local_irq_disable();
1222 list_splice_init(&per_cpu(scsi_done_q, cpu),
1223 &__get_cpu_var(scsi_done_q));
1224 raise_softirq_irqoff(SCSI_SOFTIRQ);
1233 static struct notifier_block __devinitdata scsi_cpu_nb = {
1234 .notifier_call = scsi_cpu_notify,
1237 #define register_scsi_cpu() register_cpu_notifier(&scsi_cpu_nb)
1238 #define unregister_scsi_cpu() unregister_cpu_notifier(&scsi_cpu_nb)
1240 #define register_scsi_cpu()
1241 #define unregister_scsi_cpu()
1242 #endif /* CONFIG_HOTPLUG_CPU */
1244 MODULE_DESCRIPTION("SCSI core");
1245 MODULE_LICENSE("GPL");
1247 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1248 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1250 static int __init init_scsi(void)
1254 error = scsi_init_queue();
1257 error = scsi_init_procfs();
1260 error = scsi_init_devinfo();
1262 goto cleanup_procfs;
1263 error = scsi_init_hosts();
1265 goto cleanup_devlist;
1266 error = scsi_init_sysctl();
1269 error = scsi_sysfs_register();
1271 goto cleanup_sysctl;
1273 for (i = 0; i < NR_CPUS; i++)
1274 INIT_LIST_HEAD(&per_cpu(scsi_done_q, i));
1276 devfs_mk_dir("scsi");
1277 open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL);
1278 register_scsi_cpu();
1279 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1287 scsi_exit_devinfo();
1292 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1297 static void __exit exit_scsi(void)
1299 scsi_sysfs_unregister();
1302 scsi_exit_devinfo();
1303 devfs_remove("scsi");
1306 unregister_scsi_cpu();
1309 subsys_initcall(init_scsi);
1310 module_exit(exit_scsi);