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"
71 static void scsi_done(struct scsi_cmnd *cmd);
72 static int scsi_retry_command(struct scsi_cmnd *cmd);
75 * Definitions and constants.
78 #define MIN_RESET_DELAY (2*HZ)
80 /* Do not call reset on error if we just did a reset within 15 sec. */
81 #define MIN_RESET_PERIOD (15*HZ)
84 * Macro to determine the size of SCSI command. This macro takes vendor
85 * unique commands into account. SCSI commands in groups 6 and 7 are
86 * vendor unique and we will depend upon the command length being
87 * supplied correctly in cmd_len.
89 #define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
90 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
93 * Note - the initial logging level can be set here to log events at boot time.
94 * After the system is up, you may enable logging via the /proc interface.
96 unsigned int scsi_logging_level;
97 #if defined(CONFIG_SCSI_LOGGING)
98 EXPORT_SYMBOL(scsi_logging_level);
101 const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] = {
117 EXPORT_SYMBOL(scsi_device_types);
120 * Function: scsi_allocate_request
122 * Purpose: Allocate a request descriptor.
124 * Arguments: device - device for which we want a request
125 * gfp_mask - allocation flags passed to kmalloc
127 * Lock status: No locks assumed to be held. This function is SMP-safe.
129 * Returns: Pointer to request block.
131 struct scsi_request *scsi_allocate_request(struct scsi_device *sdev,
134 const int offset = ALIGN(sizeof(struct scsi_request), 4);
135 const int size = offset + sizeof(struct request);
136 struct scsi_request *sreq;
138 sreq = kmalloc(size, gfp_mask);
139 if (likely(sreq != NULL)) {
140 memset(sreq, 0, size);
141 sreq->sr_request = (struct request *)(((char *)sreq) + offset);
142 sreq->sr_device = sdev;
143 sreq->sr_host = sdev->host;
144 sreq->sr_magic = SCSI_REQ_MAGIC;
145 sreq->sr_data_direction = DMA_BIDIRECTIONAL;
150 EXPORT_SYMBOL(scsi_allocate_request);
152 void __scsi_release_request(struct scsi_request *sreq)
154 struct request *req = sreq->sr_request;
156 /* unlikely because the tag was usually ended earlier by the
157 * mid-layer. However, for layering reasons ULD's don't end
158 * the tag of commands they generate. */
159 if (unlikely(blk_rq_tagged(req))) {
161 struct request_queue *q = req->q;
163 spin_lock_irqsave(q->queue_lock, flags);
164 blk_queue_end_tag(q, req);
165 spin_unlock_irqrestore(q->queue_lock, flags);
169 if (likely(sreq->sr_command != NULL)) {
170 struct scsi_cmnd *cmd = sreq->sr_command;
172 sreq->sr_command = NULL;
173 scsi_next_command(cmd);
178 * Function: scsi_release_request
180 * Purpose: Release a request descriptor.
182 * Arguments: sreq - request to release
184 * Lock status: No locks assumed to be held. This function is SMP-safe.
186 void scsi_release_request(struct scsi_request *sreq)
188 __scsi_release_request(sreq);
191 EXPORT_SYMBOL(scsi_release_request);
193 struct scsi_host_cmd_pool {
197 unsigned int slab_flags;
198 unsigned int gfp_mask;
201 static struct scsi_host_cmd_pool scsi_cmd_pool = {
202 .name = "scsi_cmd_cache",
203 .slab_flags = SLAB_HWCACHE_ALIGN,
206 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
207 .name = "scsi_cmd_cache(DMA)",
208 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
209 .gfp_mask = __GFP_DMA,
212 static DECLARE_MUTEX(host_cmd_pool_mutex);
214 static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost,
217 struct scsi_cmnd *cmd;
219 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
220 gfp_mask | shost->cmd_pool->gfp_mask);
222 if (unlikely(!cmd)) {
225 spin_lock_irqsave(&shost->free_list_lock, flags);
226 if (likely(!list_empty(&shost->free_list))) {
227 cmd = list_entry(shost->free_list.next,
228 struct scsi_cmnd, list);
229 list_del_init(&cmd->list);
231 spin_unlock_irqrestore(&shost->free_list_lock, flags);
238 * Function: scsi_get_command()
240 * Purpose: Allocate and setup a scsi command block
242 * Arguments: dev - parent scsi device
243 * gfp_mask- allocator flags
245 * Returns: The allocated scsi command structure.
247 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, int gfp_mask)
249 struct scsi_cmnd *cmd;
251 /* Bail if we can't get a reference to the device */
252 if (!get_device(&dev->sdev_gendev))
255 cmd = __scsi_get_command(dev->host, gfp_mask);
257 if (likely(cmd != NULL)) {
260 memset(cmd, 0, sizeof(*cmd));
262 init_timer(&cmd->eh_timeout);
263 INIT_LIST_HEAD(&cmd->list);
264 spin_lock_irqsave(&dev->list_lock, flags);
265 list_add_tail(&cmd->list, &dev->cmd_list);
266 spin_unlock_irqrestore(&dev->list_lock, flags);
268 put_device(&dev->sdev_gendev);
272 EXPORT_SYMBOL(scsi_get_command);
275 * Function: scsi_put_command()
277 * Purpose: Free a scsi command block
279 * Arguments: cmd - command block to free
283 * Notes: The command must not belong to any lists.
285 void scsi_put_command(struct scsi_cmnd *cmd)
287 struct scsi_device *sdev = cmd->device;
288 struct Scsi_Host *shost = sdev->host;
291 /* serious error if the command hasn't come from a device list */
292 spin_lock_irqsave(&cmd->device->list_lock, flags);
293 BUG_ON(list_empty(&cmd->list));
294 list_del_init(&cmd->list);
295 spin_unlock(&cmd->device->list_lock);
296 /* changing locks here, don't need to restore the irq state */
297 spin_lock(&shost->free_list_lock);
298 if (unlikely(list_empty(&shost->free_list))) {
299 list_add(&cmd->list, &shost->free_list);
302 spin_unlock_irqrestore(&shost->free_list_lock, flags);
304 if (likely(cmd != NULL))
305 kmem_cache_free(shost->cmd_pool->slab, cmd);
307 put_device(&sdev->sdev_gendev);
309 EXPORT_SYMBOL(scsi_put_command);
312 * Function: scsi_setup_command_freelist()
314 * Purpose: Setup the command freelist for a scsi host.
316 * Arguments: shost - host to allocate the freelist for.
320 int scsi_setup_command_freelist(struct Scsi_Host *shost)
322 struct scsi_host_cmd_pool *pool;
323 struct scsi_cmnd *cmd;
325 spin_lock_init(&shost->free_list_lock);
326 INIT_LIST_HEAD(&shost->free_list);
329 * Select a command slab for this host and create it if not
332 down(&host_cmd_pool_mutex);
333 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
335 pool->slab = kmem_cache_create(pool->name,
336 sizeof(struct scsi_cmnd), 0,
337 pool->slab_flags, NULL, NULL);
343 shost->cmd_pool = pool;
344 up(&host_cmd_pool_mutex);
347 * Get one backup command for this host.
349 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
350 GFP_KERNEL | shost->cmd_pool->gfp_mask);
353 list_add(&cmd->list, &shost->free_list);
358 kmem_cache_destroy(pool->slab);
361 up(&host_cmd_pool_mutex);
367 * Function: scsi_destroy_command_freelist()
369 * Purpose: Release the command freelist for a scsi host.
371 * Arguments: shost - host that's freelist is going to be destroyed
373 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
375 while (!list_empty(&shost->free_list)) {
376 struct scsi_cmnd *cmd;
378 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
379 list_del_init(&cmd->list);
380 kmem_cache_free(shost->cmd_pool->slab, cmd);
383 down(&host_cmd_pool_mutex);
384 if (!--shost->cmd_pool->users)
385 kmem_cache_destroy(shost->cmd_pool->slab);
386 up(&host_cmd_pool_mutex);
389 #ifdef CONFIG_SCSI_LOGGING
390 void scsi_log_send(struct scsi_cmnd *cmd)
393 struct scsi_device *sdev;
396 * If ML QUEUE log level is greater than or equal to:
398 * 1: nothing (match completion)
400 * 2: log opcode + command of all commands
402 * 3: same as 2 plus dump cmd address
404 * 4: same as 3 plus dump extra junk
406 if (unlikely(scsi_logging_level)) {
407 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
408 SCSI_LOG_MLQUEUE_BITS);
411 printk(KERN_INFO "scsi <%d:%d:%d:%d> send ",
412 sdev->host->host_no, sdev->channel, sdev->id,
415 printk("0x%p ", cmd);
417 * spaces to match disposition and cmd->result
418 * output in scsi_log_completion.
421 scsi_print_command(cmd);
423 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
424 " done = 0x%p, queuecommand 0x%p\n",
425 cmd->buffer, cmd->bufflen,
427 sdev->host->hostt->queuecommand);
434 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
437 struct scsi_device *sdev;
440 * If ML COMPLETE log level is greater than or equal to:
442 * 1: log disposition, result, opcode + command, and conditionally
443 * sense data for failures or non SUCCESS dispositions.
445 * 2: same as 1 but for all command completions.
447 * 3: same as 2 plus dump cmd address
449 * 4: same as 3 plus dump extra junk
451 if (unlikely(scsi_logging_level)) {
452 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
453 SCSI_LOG_MLCOMPLETE_BITS);
454 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
457 printk(KERN_INFO "scsi <%d:%d:%d:%d> done ",
458 sdev->host->host_no, sdev->channel, sdev->id,
461 printk("0x%p ", cmd);
463 * Dump truncated values, so we usually fit within
466 switch (disposition) {
481 * If called via scsi_times_out.
488 printk(" %8x ", cmd->result);
489 scsi_print_command(cmd);
490 if (status_byte(cmd->result) & CHECK_CONDITION) {
492 * XXX The scsi_print_sense formatting/prefix
493 * doesn't match this function.
495 scsi_print_sense("", cmd);
498 printk(KERN_INFO "scsi host busy %d failed %d\n",
499 sdev->host->host_busy,
500 sdev->host->host_failed);
508 * Assign a serial number and pid to the request for error recovery
509 * and debugging purposes. Protected by the Host_Lock of host.
511 static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
513 cmd->serial_number = host->cmd_serial_number++;
514 if (cmd->serial_number == 0)
515 cmd->serial_number = host->cmd_serial_number++;
517 cmd->pid = host->cmd_pid++;
519 cmd->pid = host->cmd_pid++;
523 * Function: scsi_dispatch_command
525 * Purpose: Dispatch a command to the low-level driver.
527 * Arguments: cmd - command block we are dispatching.
531 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
533 struct Scsi_Host *host = cmd->device->host;
534 unsigned long flags = 0;
535 unsigned long timeout;
538 /* check if the device is still usable */
539 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
540 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
541 * returns an immediate error upwards, and signals
542 * that the device is no longer present */
543 cmd->result = DID_NO_CONNECT << 16;
544 atomic_inc(&cmd->device->iorequest_cnt);
546 /* return 0 (because the command has been processed) */
550 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
551 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
553 * in SDEV_BLOCK, the command is just put back on the device
554 * queue. The suspend state has already blocked the queue so
555 * future requests should not occur until the device
556 * transitions out of the suspend state.
558 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
560 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
563 * NOTE: rtn is still zero here because we don't need the
564 * queue to be plugged on return (it's already stopped)
570 * If SCSI-2 or lower, store the LUN value in cmnd.
572 if (cmd->device->scsi_level <= SCSI_2) {
573 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
574 (cmd->device->lun << 5 & 0xe0);
578 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
579 * we can avoid the drive not being ready.
581 timeout = host->last_reset + MIN_RESET_DELAY;
583 if (host->resetting && time_before(jiffies, timeout)) {
584 int ticks_remaining = timeout - jiffies;
586 * NOTE: This may be executed from within an interrupt
587 * handler! This is bad, but for now, it'll do. The irq
588 * level of the interrupt handler has been masked out by the
589 * platform dependent interrupt handling code already, so the
590 * sti() here will not cause another call to the SCSI host's
591 * interrupt handler (assuming there is one irq-level per
594 while (--ticks_remaining >= 0)
595 mdelay(1 + 999 / HZ);
600 * AK: unlikely race here: for some reason the timer could
601 * expire before the serial number is set up below.
603 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
608 * We will use a queued command if possible, otherwise we will
609 * emulate the queuing and calling of completion function ourselves.
611 atomic_inc(&cmd->device->iorequest_cnt);
614 * Before we queue this command, check if the command
615 * length exceeds what the host adapter can handle.
617 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
619 printk("queuecommand : command too long.\n"));
620 cmd->result = (DID_ABORT << 16);
626 spin_lock_irqsave(host->host_lock, flags);
627 scsi_cmd_get_serial(host, cmd);
629 if (unlikely(test_bit(SHOST_CANCEL, &host->shost_state))) {
630 cmd->result = (DID_NO_CONNECT << 16);
633 rtn = host->hostt->queuecommand(cmd, scsi_done);
635 spin_unlock_irqrestore(host->host_lock, flags);
637 if (scsi_delete_timer(cmd)) {
638 atomic_inc(&cmd->device->iodone_cnt);
639 scsi_queue_insert(cmd,
640 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
641 rtn : SCSI_MLQUEUE_HOST_BUSY);
644 printk("queuecommand : request rejected\n"));
648 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
653 * Function: scsi_init_cmd_from_req
655 * Purpose: Queue a SCSI command
656 * Purpose: Initialize a struct scsi_cmnd from a struct scsi_request
658 * Arguments: cmd - command descriptor.
659 * sreq - Request from the queue.
661 * Lock status: None needed.
665 * Notes: Mainly transfer data from the request structure to the
666 * command structure. The request structure is allocated
667 * using the normal memory allocator, and requests can pile
668 * up to more or less any depth. The command structure represents
669 * a consumable resource, as these are allocated into a pool
670 * when the SCSI subsystem initializes. The preallocation is
671 * required so that in low-memory situations a disk I/O request
672 * won't cause the memory manager to try and write out a page.
673 * The request structure is generally used by ioctls and character
676 void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq)
678 sreq->sr_command = cmd;
680 cmd->cmd_len = sreq->sr_cmd_len;
681 cmd->use_sg = sreq->sr_use_sg;
683 cmd->request = sreq->sr_request;
684 memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd));
685 cmd->serial_number = 0;
686 cmd->bufflen = sreq->sr_bufflen;
687 cmd->buffer = sreq->sr_buffer;
689 cmd->allowed = sreq->sr_allowed;
690 cmd->done = sreq->sr_done;
691 cmd->timeout_per_command = sreq->sr_timeout_per_command;
692 cmd->sc_data_direction = sreq->sr_data_direction;
693 cmd->sglist_len = sreq->sr_sglist_len;
694 cmd->underflow = sreq->sr_underflow;
695 cmd->sc_request = sreq;
696 memcpy(cmd->cmnd, sreq->sr_cmnd, sizeof(sreq->sr_cmnd));
699 * Zero the sense buffer. Some host adapters automatically request
700 * sense on error. 0 is not a valid sense code.
702 memset(cmd->sense_buffer, 0, sizeof(sreq->sr_sense_buffer));
703 cmd->request_buffer = sreq->sr_buffer;
704 cmd->request_bufflen = sreq->sr_bufflen;
705 cmd->old_use_sg = cmd->use_sg;
706 if (cmd->cmd_len == 0)
707 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
708 cmd->old_cmd_len = cmd->cmd_len;
709 cmd->sc_old_data_direction = cmd->sc_data_direction;
710 cmd->old_underflow = cmd->underflow;
713 * Start the timer ticking.
717 SCSI_LOG_MLQUEUE(3, printk("Leaving scsi_init_cmd_from_req()\n"));
721 * Per-CPU I/O completion queue.
723 static DEFINE_PER_CPU(struct list_head, scsi_done_q);
726 * scsi_done - Enqueue the finished SCSI command into the done queue.
727 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
728 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
730 * This function is the mid-level's (SCSI Core) interrupt routine, which
731 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
732 * the command to the done queue for further processing.
734 * This is the producer of the done queue who enqueues at the tail.
736 * This function is interrupt context safe.
738 static void scsi_done(struct scsi_cmnd *cmd)
741 * We don't have to worry about this one timing out any more.
742 * If we are unable to remove the timer, then the command
743 * has already timed out. In which case, we have no choice but to
744 * let the timeout function run, as we have no idea where in fact
745 * that function could really be. It might be on another processor,
748 if (!scsi_delete_timer(cmd))
753 /* Private entry to scsi_done() to complete a command when the timer
754 * isn't running --- used by scsi_times_out */
755 void __scsi_done(struct scsi_cmnd *cmd)
760 * Set the serial numbers back to zero
762 cmd->serial_number = 0;
764 atomic_inc(&cmd->device->iodone_cnt);
766 atomic_inc(&cmd->device->ioerr_cnt);
769 * Next, enqueue the command into the done queue.
770 * It is a per-CPU queue, so we just disable local interrupts
771 * and need no spinlock.
773 local_irq_save(flags);
774 list_add_tail(&cmd->eh_entry, &__get_cpu_var(scsi_done_q));
775 raise_softirq_irqoff(SCSI_SOFTIRQ);
776 local_irq_restore(flags);
780 * scsi_softirq - Perform post-interrupt processing of finished SCSI commands.
782 * This is the consumer of the done queue.
784 * This is called with all interrupts enabled. This should reduce
785 * interrupt latency, stack depth, and reentrancy of the low-level
788 static void scsi_softirq(struct softirq_action *h)
794 list_splice_init(&__get_cpu_var(scsi_done_q), &local_q);
797 while (!list_empty(&local_q)) {
798 struct scsi_cmnd *cmd = list_entry(local_q.next,
799 struct scsi_cmnd, eh_entry);
800 list_del_init(&cmd->eh_entry);
802 disposition = scsi_decide_disposition(cmd);
803 scsi_log_completion(cmd, disposition);
804 switch (disposition) {
806 scsi_finish_command(cmd);
809 scsi_retry_command(cmd);
812 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
815 if (!scsi_eh_scmd_add(cmd, 0))
816 scsi_finish_command(cmd);
822 * Function: scsi_retry_command
824 * Purpose: Send a command back to the low level to be retried.
826 * Notes: This command is always executed in the context of the
827 * bottom half handler, or the error handler thread. Low
828 * level drivers should not become re-entrant as a result of
831 static int scsi_retry_command(struct scsi_cmnd *cmd)
834 * Restore the SCSI command state.
836 scsi_setup_cmd_retry(cmd);
839 * Zero the sense information from the last time we tried
842 memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
844 return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
848 * Function: scsi_finish_command
850 * Purpose: Pass command off to upper layer for finishing of I/O
851 * request, waking processes that are waiting on results,
854 void scsi_finish_command(struct scsi_cmnd *cmd)
856 struct scsi_device *sdev = cmd->device;
857 struct Scsi_Host *shost = sdev->host;
858 struct scsi_request *sreq;
860 scsi_device_unbusy(sdev);
863 * Clear the flags which say that the device/host is no longer
864 * capable of accepting new commands. These are set in scsi_queue.c
865 * for both the queue full condition on a device, and for a
866 * host full condition on the host.
868 * XXX(hch): What about locking?
870 shost->host_blocked = 0;
871 sdev->device_blocked = 0;
874 * If we have valid sense information, then some kind of recovery
875 * must have taken place. Make a note of this.
877 if (SCSI_SENSE_VALID(cmd))
878 cmd->result |= (DRIVER_SENSE << 24);
880 SCSI_LOG_MLCOMPLETE(4, printk("Notifying upper driver of completion "
881 "for device %d %x\n", sdev->id, cmd->result));
884 * We can get here with use_sg=0, causing a panic in the upper level
886 cmd->use_sg = cmd->old_use_sg;
889 * If there is an associated request structure, copy the data over
890 * before we call the completion function.
892 sreq = cmd->sc_request;
894 sreq->sr_result = sreq->sr_command->result;
895 if (sreq->sr_result) {
896 memcpy(sreq->sr_sense_buffer,
897 sreq->sr_command->sense_buffer,
898 sizeof(sreq->sr_sense_buffer));
904 EXPORT_SYMBOL(scsi_finish_command);
907 * Function: scsi_adjust_queue_depth()
909 * Purpose: Allow low level drivers to tell us to change the queue depth
910 * on a specific SCSI device
912 * Arguments: sdev - SCSI Device in question
913 * tagged - Do we use tagged queueing (non-0) or do we treat
914 * this device as an untagged device (0)
915 * tags - Number of tags allowed if tagged queueing enabled,
916 * or number of commands the low level driver can
917 * queue up in non-tagged mode (as per cmd_per_lun).
921 * Lock Status: None held on entry
923 * Notes: Low level drivers may call this at any time and we will do
924 * the right thing depending on whether or not the device is
925 * currently active and whether or not it even has the
926 * command blocks built yet.
928 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
933 * refuse to set tagged depth to an unworkable size
938 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
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_irqrestore(sdev->request_queue->queue_lock, flags);
969 EXPORT_SYMBOL(scsi_adjust_queue_depth);
972 * Function: scsi_track_queue_full()
974 * Purpose: This function will track successive QUEUE_FULL events on a
975 * specific SCSI device to determine if and when there is a
976 * need to adjust the queue depth on the device.
978 * Arguments: sdev - SCSI Device in question
979 * depth - Current number of outstanding SCSI commands on
980 * this device, not counting the one returned as
983 * Returns: 0 - No change needed
984 * >0 - Adjust queue depth to this new depth
985 * -1 - Drop back to untagged operation using host->cmd_per_lun
986 * as the untagged command depth
988 * Lock Status: None held on entry
990 * Notes: Low level drivers may call this at any time and we will do
991 * "The Right Thing." We are interrupt context safe.
993 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
995 if ((jiffies >> 4) == sdev->last_queue_full_time)
998 sdev->last_queue_full_time = (jiffies >> 4);
999 if (sdev->last_queue_full_depth != depth) {
1000 sdev->last_queue_full_count = 1;
1001 sdev->last_queue_full_depth = depth;
1003 sdev->last_queue_full_count++;
1006 if (sdev->last_queue_full_count <= 10)
1008 if (sdev->last_queue_full_depth < 8) {
1009 /* Drop back to untagged */
1010 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
1014 if (sdev->ordered_tags)
1015 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
1017 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
1020 EXPORT_SYMBOL(scsi_track_queue_full);
1023 * scsi_device_get - get an addition reference to a scsi_device
1024 * @sdev: device to get a reference to
1026 * Gets a reference to the scsi_device and increments the use count
1027 * of the underlying LLDD module. You must hold host_lock of the
1028 * parent Scsi_Host or already have a reference when calling this.
1030 int scsi_device_get(struct scsi_device *sdev)
1032 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
1034 if (!get_device(&sdev->sdev_gendev))
1036 if (!try_module_get(sdev->host->hostt->module)) {
1037 put_device(&sdev->sdev_gendev);
1042 EXPORT_SYMBOL(scsi_device_get);
1045 * scsi_device_put - release a reference to a scsi_device
1046 * @sdev: device to release a reference on.
1048 * Release a reference to the scsi_device and decrements the use count
1049 * of the underlying LLDD module. The device is freed once the last
1052 void scsi_device_put(struct scsi_device *sdev)
1054 module_put(sdev->host->hostt->module);
1055 put_device(&sdev->sdev_gendev);
1057 EXPORT_SYMBOL(scsi_device_put);
1059 /* helper for shost_for_each_device, thus not documented */
1060 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1061 struct scsi_device *prev)
1063 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1064 struct scsi_device *next = NULL;
1065 unsigned long flags;
1067 spin_lock_irqsave(shost->host_lock, flags);
1068 while (list->next != &shost->__devices) {
1069 next = list_entry(list->next, struct scsi_device, siblings);
1070 /* skip devices that we can't get a reference to */
1071 if (!scsi_device_get(next))
1076 spin_unlock_irqrestore(shost->host_lock, flags);
1079 scsi_device_put(prev);
1082 EXPORT_SYMBOL(__scsi_iterate_devices);
1085 * starget_for_each_device - helper to walk all devices of a target
1086 * @starget: target whose devices we want to iterate over.
1088 * This traverses over each devices of @shost. The devices have
1089 * a reference that must be released by scsi_host_put when breaking
1092 void starget_for_each_device(struct scsi_target *starget, void * data,
1093 void (*fn)(struct scsi_device *, void *))
1095 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1096 struct scsi_device *sdev;
1098 shost_for_each_device(sdev, shost) {
1099 if ((sdev->channel == starget->channel) &&
1100 (sdev->id == starget->id))
1104 EXPORT_SYMBOL(starget_for_each_device);
1107 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1108 * @starget: SCSI target pointer
1109 * @lun: SCSI Logical Unit Number
1111 * Looks up the scsi_device with the specified @lun for a give
1112 * @starget. The returned scsi_device does not have an additional
1113 * reference. You must hold the host's host_lock over this call and
1114 * any access to the returned scsi_device.
1116 * Note: The only reason why drivers would want to use this is because
1117 * they're need to access the device list in irq context. Otherwise you
1118 * really want to use scsi_device_lookup_by_target instead.
1120 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1123 struct scsi_device *sdev;
1125 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1126 if (sdev->lun ==lun)
1132 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1135 * scsi_device_lookup_by_target - find a device given the target
1136 * @starget: SCSI target pointer
1137 * @lun: SCSI Logical Unit Number
1139 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1140 * give host. The returned scsi_device has an additional reference that
1141 * needs to be release with scsi_host_put once you're done with it.
1143 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1146 struct scsi_device *sdev;
1147 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1148 unsigned long flags;
1150 spin_lock_irqsave(shost->host_lock, flags);
1151 sdev = __scsi_device_lookup_by_target(starget, lun);
1152 if (sdev && scsi_device_get(sdev))
1154 spin_unlock_irqrestore(shost->host_lock, flags);
1158 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1161 * scsi_device_lookup - find a device given the host (UNLOCKED)
1162 * @shost: SCSI host pointer
1163 * @channel: SCSI channel (zero if only one channel)
1164 * @pun: SCSI target number (physical unit number)
1165 * @lun: SCSI Logical Unit Number
1167 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1168 * give host. The returned scsi_device does not have an additional reference.
1169 * You must hold the host's host_lock over this call and any access to the
1170 * returned scsi_device.
1172 * Note: The only reason why drivers would want to use this is because
1173 * they're need to access the device list in irq context. Otherwise you
1174 * really want to use scsi_device_lookup instead.
1176 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1177 uint channel, uint id, uint lun)
1179 struct scsi_device *sdev;
1181 list_for_each_entry(sdev, &shost->__devices, siblings) {
1182 if (sdev->channel == channel && sdev->id == id &&
1189 EXPORT_SYMBOL(__scsi_device_lookup);
1192 * scsi_device_lookup - find a device given the host
1193 * @shost: SCSI host pointer
1194 * @channel: SCSI channel (zero if only one channel)
1195 * @id: SCSI target number (physical unit number)
1196 * @lun: SCSI Logical Unit Number
1198 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1199 * give host. The returned scsi_device has an additional reference that
1200 * needs to be release with scsi_host_put once you're done with it.
1202 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1203 uint channel, uint id, uint lun)
1205 struct scsi_device *sdev;
1206 unsigned long flags;
1208 spin_lock_irqsave(shost->host_lock, flags);
1209 sdev = __scsi_device_lookup(shost, channel, id, lun);
1210 if (sdev && scsi_device_get(sdev))
1212 spin_unlock_irqrestore(shost->host_lock, flags);
1216 EXPORT_SYMBOL(scsi_device_lookup);
1219 * scsi_device_cancel - cancel outstanding IO to this device
1220 * @sdev: Pointer to struct scsi_device
1221 * @recovery: Boolean instructing function to recover device or not.
1224 int scsi_device_cancel(struct scsi_device *sdev, int recovery)
1226 struct scsi_cmnd *scmd;
1227 LIST_HEAD(active_list);
1228 struct list_head *lh, *lh_sf;
1229 unsigned long flags;
1231 scsi_device_set_state(sdev, SDEV_CANCEL);
1233 spin_lock_irqsave(&sdev->list_lock, flags);
1234 list_for_each_entry(scmd, &sdev->cmd_list, list) {
1235 if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) {
1237 * If we are unable to remove the timer, it means
1238 * that the command has already timed out or
1241 if (!scsi_delete_timer(scmd))
1243 list_add_tail(&scmd->eh_entry, &active_list);
1246 spin_unlock_irqrestore(&sdev->list_lock, flags);
1248 if (!list_empty(&active_list)) {
1249 list_for_each_safe(lh, lh_sf, &active_list) {
1250 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1253 scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
1255 scmd->result = (DID_ABORT << 16);
1256 scsi_finish_command(scmd);
1263 EXPORT_SYMBOL(scsi_device_cancel);
1265 #ifdef CONFIG_HOTPLUG_CPU
1266 static int scsi_cpu_notify(struct notifier_block *self,
1267 unsigned long action, void *hcpu)
1269 int cpu = (unsigned long)hcpu;
1273 /* Drain scsi_done_q. */
1274 local_irq_disable();
1275 list_splice_init(&per_cpu(scsi_done_q, cpu),
1276 &__get_cpu_var(scsi_done_q));
1277 raise_softirq_irqoff(SCSI_SOFTIRQ);
1286 static struct notifier_block __devinitdata scsi_cpu_nb = {
1287 .notifier_call = scsi_cpu_notify,
1290 #define register_scsi_cpu() register_cpu_notifier(&scsi_cpu_nb)
1291 #define unregister_scsi_cpu() unregister_cpu_notifier(&scsi_cpu_nb)
1293 #define register_scsi_cpu()
1294 #define unregister_scsi_cpu()
1295 #endif /* CONFIG_HOTPLUG_CPU */
1297 MODULE_DESCRIPTION("SCSI core");
1298 MODULE_LICENSE("GPL");
1300 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1301 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1303 static int __init init_scsi(void)
1307 error = scsi_init_queue();
1310 error = scsi_init_procfs();
1313 error = scsi_init_devinfo();
1315 goto cleanup_procfs;
1316 error = scsi_init_hosts();
1318 goto cleanup_devlist;
1319 error = scsi_init_sysctl();
1322 error = scsi_sysfs_register();
1324 goto cleanup_sysctl;
1326 for (i = 0; i < NR_CPUS; i++)
1327 INIT_LIST_HEAD(&per_cpu(scsi_done_q, i));
1329 devfs_mk_dir("scsi");
1330 open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL);
1331 register_scsi_cpu();
1332 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1340 scsi_exit_devinfo();
1345 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1350 static void __exit exit_scsi(void)
1352 scsi_sysfs_unregister();
1355 scsi_exit_devinfo();
1356 devfs_remove("scsi");
1359 unregister_scsi_cpu();
1362 subsys_initcall(init_scsi);
1363 module_exit(exit_scsi);