/* * scsi.c Copyright (C) 1992 Drew Eckhardt * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale * Copyright (C) 2002, 2003 Christoph Hellwig * * generic mid-level SCSI driver * Initial versions: Drew Eckhardt * Subsequent revisions: Eric Youngdale * * <drew@colorado.edu> * * Bug correction thanks go to : * Rik Faith <faith@cs.unc.edu> * Tommy Thorn <tthorn> * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de> * * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to * add scatter-gather, multiple outstanding request, and other * enhancements. * * Native multichannel, wide scsi, /proc/scsi and hot plugging * support added by Michael Neuffer <mike@i-connect.net> * * Added request_module("scsi_hostadapter") for kerneld: * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf) * Bjorn Ekwall <bj0rn@blox.se> * (changed to kmod) * * Major improvements to the timeout, abort, and reset processing, * as well as performance modifications for large queue depths by * Leonard N. Zubkoff <lnz@dandelion.com> * * Converted cli() code to spinlocks, Ingo Molnar * * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli * * out_of_space hacks, D. Gilbert (dpg) 990608 */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/kernel.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/blkdev.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/completion.h> #include <linux/unistd.h> #include <linux/spinlock.h> #include <linux/kmod.h> #include <linux/interrupt.h> #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/mutex.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_dbg.h> #include <scsi/scsi_device.h> #include <scsi/scsi_driver.h> #include <scsi/scsi_eh.h> #include <scsi/scsi_host.h> #include <scsi/scsi_tcq.h> #include "scsi_priv.h" #include "scsi_logging.h" static void scsi_done(struct scsi_cmnd *cmd); /* * Definitions and constants. */ #define MIN_RESET_DELAY (2*HZ) /* Do not call reset on error if we just did a reset within 15 sec. */ #define MIN_RESET_PERIOD (15*HZ) /* * Note - the initial logging level can be set here to log events at boot time. * After the system is up, you may enable logging via the /proc interface. */ unsigned int scsi_logging_level; #if defined(CONFIG_SCSI_LOGGING) EXPORT_SYMBOL(scsi_logging_level); #endif /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI. * You may not alter any existing entry (although adding new ones is * encouraged once assigned by ANSI/INCITS T10 */ static const char *const scsi_device_types[] = { "Direct-Access ", "Sequential-Access", "Printer ", "Processor ", "WORM ", "CD-ROM ", "Scanner ", "Optical Device ", "Medium Changer ", "Communications ", "ASC IT8 ", "ASC IT8 ", "RAID ", "Enclosure ", "Direct-Access-RBC", "Optical card ", "Bridge controller", "Object storage ", "Automation/Drive ", }; /** * scsi_device_type - Return 17 char string indicating device type. * @type: type number to look up */ const char * scsi_device_type(unsigned type) { if (type == 0x1e) return "Well-known LUN "; if (type == 0x1f) return "No Device "; if (type >= ARRAY_SIZE(scsi_device_types)) return "Unknown "; return scsi_device_types[type]; } EXPORT_SYMBOL(scsi_device_type); struct scsi_host_cmd_pool { struct kmem_cache *cmd_slab; struct kmem_cache *sense_slab; unsigned int users; char *cmd_name; char *sense_name; unsigned int slab_flags; gfp_t gfp_mask; }; static struct scsi_host_cmd_pool scsi_cmd_pool = { .cmd_name = "scsi_cmd_cache", .sense_name = "scsi_sense_cache", .slab_flags = SLAB_HWCACHE_ALIGN, }; static struct scsi_host_cmd_pool scsi_cmd_dma_pool = { .cmd_name = "scsi_cmd_cache(DMA)", .sense_name = "scsi_sense_cache(DMA)", .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA, .gfp_mask = __GFP_DMA, }; static DEFINE_MUTEX(host_cmd_pool_mutex); /** * scsi_pool_alloc_command - internal function to get a fully allocated command * @pool: slab pool to allocate the command from * @gfp_mask: mask for the allocation * * Returns a fully allocated command (with the allied sense buffer) or * NULL on failure */ static struct scsi_cmnd * scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask) { struct scsi_cmnd *cmd; cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask); if (!cmd) return NULL; cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab, gfp_mask | pool->gfp_mask); if (!cmd->sense_buffer) { kmem_cache_free(pool->cmd_slab, cmd); return NULL; } return cmd; } /** * scsi_pool_free_command - internal function to release a command * @pool: slab pool to allocate the command from * @cmd: command to release * * the command must previously have been allocated by * scsi_pool_alloc_command. */ static void scsi_pool_free_command(struct scsi_host_cmd_pool *pool, struct scsi_cmnd *cmd) { if (cmd->prot_sdb) kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb); kmem_cache_free(pool->sense_slab, cmd->sense_buffer); kmem_cache_free(pool->cmd_slab, cmd); } /** * scsi_host_alloc_command - internal function to allocate command * @shost: SCSI host whose pool to allocate from * @gfp_mask: mask for the allocation * * Returns a fully allocated command with sense buffer and protection * data buffer (where applicable) or NULL on failure */ static struct scsi_cmnd * scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask) { struct scsi_cmnd *cmd; cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask); if (!cmd) return NULL; if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) { cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask); if (!cmd->prot_sdb) { scsi_pool_free_command(shost->cmd_pool, cmd); return NULL; } } return cmd; } /** * __scsi_get_command - Allocate a struct scsi_cmnd * @shost: host to transmit command * @gfp_mask: allocation mask * * Description: allocate a struct scsi_cmd from host's slab, recycling from the * host's free_list if necessary. */ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask) { struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask); if (unlikely(!cmd)) { unsigned long flags; spin_lock_irqsave(&shost->free_list_lock, flags); if (likely(!list_empty(&shost->free_list))) { cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list); list_del_init(&cmd->list); } spin_unlock_irqrestore(&shost->free_list_lock, flags); if (cmd) { void *buf, *prot; buf = cmd->sense_buffer; prot = cmd->prot_sdb; memset(cmd, 0, sizeof(*cmd)); cmd->sense_buffer = buf; cmd->prot_sdb = prot; } } return cmd; } EXPORT_SYMBOL_GPL(__scsi_get_command); /** * scsi_get_command - Allocate and setup a scsi command block * @dev: parent scsi device * @gfp_mask: allocator flags * * Returns: The allocated scsi command structure. */ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) { struct scsi_cmnd *cmd; /* Bail if we can't get a reference to the device */ if (!get_device(&dev->sdev_gendev)) return NULL; cmd = __scsi_get_command(dev->host, gfp_mask); if (likely(cmd != NULL)) { unsigned long flags; cmd->device = dev; INIT_LIST_HEAD(&cmd->list); spin_lock_irqsave(&dev->list_lock, flags); list_add_tail(&cmd->list, &dev->cmd_list); spin_unlock_irqrestore(&dev->list_lock, flags); cmd->jiffies_at_alloc = jiffies; } else put_device(&dev->sdev_gendev); return cmd; } EXPORT_SYMBOL(scsi_get_command); /** * __scsi_put_command - Free a struct scsi_cmnd * @shost: dev->host * @cmd: Command to free * @dev: parent scsi device */ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd, struct device *dev) { unsigned long flags; /* changing locks here, don't need to restore the irq state */ spin_lock_irqsave(&shost->free_list_lock, flags); if (unlikely(list_empty(&shost->free_list))) { list_add(&cmd->list, &shost->free_list); cmd = NULL; } spin_unlock_irqrestore(&shost->free_list_lock, flags); if (likely(cmd != NULL)) scsi_pool_free_command(shost->cmd_pool, cmd); put_device(dev); } EXPORT_SYMBOL(__scsi_put_command); /** * scsi_put_command - Free a scsi command block * @cmd: command block to free * * Returns: Nothing. * * Notes: The command must not belong to any lists. */ void scsi_put_command(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; unsigned long flags; /* serious error if the command hasn't come from a device list */ spin_lock_irqsave(&cmd->device->list_lock, flags); BUG_ON(list_empty(&cmd->list)); list_del_init(&cmd->list); spin_unlock_irqrestore(&cmd->device->list_lock, flags); __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev); } EXPORT_SYMBOL(scsi_put_command); static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask) { struct scsi_host_cmd_pool *retval = NULL, *pool; /* * Select a command slab for this host and create it if not * yet existent. */ mutex_lock(&host_cmd_pool_mutex); pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool : &scsi_cmd_pool; if (!pool->users) { pool->cmd_slab = kmem_cache_create(pool->cmd_name, sizeof(struct scsi_cmnd), 0, pool->slab_flags, NULL); if (!pool->cmd_slab) goto fail; pool->sense_slab = kmem_cache_create(pool->sense_name, SCSI_SENSE_BUFFERSIZE, 0, pool->slab_flags, NULL); if (!pool->sense_slab) { kmem_cache_destroy(pool->cmd_slab); goto fail; } } pool->users++; retval = pool; fail: mutex_unlock(&host_cmd_pool_mutex); return retval; } static void scsi_put_host_cmd_pool(gfp_t gfp_mask) { struct scsi_host_cmd_pool *pool; mutex_lock(&host_cmd_pool_mutex); pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool : &scsi_cmd_pool; /* * This may happen if a driver has a mismatched get and put * of the command pool; the driver should be implicated in * the stack trace */ BUG_ON(pool->users == 0); if (!--pool->users) { kmem_cache_destroy(pool->cmd_slab); kmem_cache_destroy(pool->sense_slab); } mutex_unlock(&host_cmd_pool_mutex); } /** * scsi_allocate_command - get a fully allocated SCSI command * @gfp_mask: allocation mask * * This function is for use outside of the normal host based pools. * It allocates the relevant command and takes an additional reference * on the pool it used. This function *must* be paired with * scsi_free_command which also has the identical mask, otherwise the * free pool counts will eventually go wrong and you'll trigger a bug. * * This function should *only* be used by drivers that need a static * command allocation at start of day for internal functions. */ struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask) { struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask); if (!pool) return NULL; return scsi_pool_alloc_command(pool, gfp_mask); } EXPORT_SYMBOL(scsi_allocate_command); /** * scsi_free_command - free a command allocated by scsi_allocate_command * @gfp_mask: mask used in the original allocation * @cmd: command to free * * Note: using the original allocation mask is vital because that's * what determines which command pool we use to free the command. Any * mismatch will cause the system to BUG eventually. */ void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd) { struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask); /* * this could trigger if the mask to scsi_allocate_command * doesn't match this mask. Otherwise we're guaranteed that this * succeeds because scsi_allocate_command must have taken a reference * on the pool */ BUG_ON(!pool); scsi_pool_free_command(pool, cmd); /* * scsi_put_host_cmd_pool is called twice; once to release the * reference we took above, and once to release the reference * originally taken by scsi_allocate_command */ scsi_put_host_cmd_pool(gfp_mask); scsi_put_host_cmd_pool(gfp_mask); } EXPORT_SYMBOL(scsi_free_command); /** * scsi_setup_command_freelist - Setup the command freelist for a scsi host. * @shost: host to allocate the freelist for. * * Description: The command freelist protects against system-wide out of memory * deadlock by preallocating one SCSI command structure for each host, so the * system can always write to a swap file on a device associated with that host. * * Returns: Nothing. */ int scsi_setup_command_freelist(struct Scsi_Host *shost) { struct scsi_cmnd *cmd; const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL; spin_lock_init(&shost->free_list_lock); INIT_LIST_HEAD(&shost->free_list); shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask); if (!shost->cmd_pool) return -ENOMEM; /* * Get one backup command for this host. */ cmd = scsi_host_alloc_command(shost, gfp_mask); if (!cmd) { scsi_put_host_cmd_pool(gfp_mask); shost->cmd_pool = NULL; return -ENOMEM; } list_add(&cmd->list, &shost->free_list); return 0; } /** * scsi_destroy_command_freelist - Release the command freelist for a scsi host. * @shost: host whose freelist is going to be destroyed */ void scsi_destroy_command_freelist(struct Scsi_Host *shost) { /* * If cmd_pool is NULL the free list was not initialized, so * do not attempt to release resources. */ if (!shost->cmd_pool) return; while (!list_empty(&shost->free_list)) { struct scsi_cmnd *cmd; cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list); list_del_init(&cmd->list); scsi_pool_free_command(shost->cmd_pool, cmd); } shost->cmd_pool = NULL; scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL); } #ifdef CONFIG_SCSI_LOGGING void scsi_log_send(struct scsi_cmnd *cmd) { unsigned int level; /* * If ML QUEUE log level is greater than or equal to: * * 1: nothing (match completion) * * 2: log opcode + command of all commands * * 3: same as 2 plus dump cmd address * * 4: same as 3 plus dump extra junk */ if (unlikely(scsi_logging_level)) { level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT, SCSI_LOG_MLQUEUE_BITS); if (level > 1) { scmd_printk(KERN_INFO, cmd, "Send: "); if (level > 2) printk("0x%p ", cmd); printk("\n"); scsi_print_command(cmd); if (level > 3) { printk(KERN_INFO "buffer = 0x%p, bufflen = %d," " queuecommand 0x%p\n", scsi_sglist(cmd), scsi_bufflen(cmd), cmd->device->host->hostt->queuecommand); } } } } void scsi_log_completion(struct scsi_cmnd *cmd, int disposition) { unsigned int level; /* * If ML COMPLETE log level is greater than or equal to: * * 1: log disposition, result, opcode + command, and conditionally * sense data for failures or non SUCCESS dispositions. * * 2: same as 1 but for all command completions. * * 3: same as 2 plus dump cmd address * * 4: same as 3 plus dump extra junk */ if (unlikely(scsi_logging_level)) { level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, SCSI_LOG_MLCOMPLETE_BITS); if (((level > 0) && (cmd->result || disposition != SUCCESS)) || (level > 1)) { scmd_printk(KERN_INFO, cmd, "Done: "); if (level > 2) printk("0x%p ", cmd); /* * Dump truncated values, so we usually fit within * 80 chars. */ switch (disposition) { case SUCCESS: printk("SUCCESS\n"); break; case NEEDS_RETRY: printk("RETRY\n"); break; case ADD_TO_MLQUEUE: printk("MLQUEUE\n"); break; case FAILED: printk("FAILED\n"); break; case TIMEOUT_ERROR: /* * If called via scsi_times_out. */ printk("TIMEOUT\n"); break; default: printk("UNKNOWN\n"); } scsi_print_result(cmd); scsi_print_command(cmd); if (status_byte(cmd->result) & CHECK_CONDITION) scsi_print_sense("", cmd); if (level > 3) scmd_printk(KERN_INFO, cmd, "scsi host busy %d failed %d\n", cmd->device->host->host_busy, cmd->device->host->host_failed); } } } #endif /** * scsi_cmd_get_serial - Assign a serial number to a command * @host: the scsi host * @cmd: command to assign serial number to * * Description: a serial number identifies a request for error recovery * and debugging purposes. Protected by the Host_Lock of host. */ static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd) { cmd->serial_number = host->cmd_serial_number++; if (cmd->serial_number == 0) cmd->serial_number = host->cmd_serial_number++; } /** * scsi_dispatch_command - Dispatch a command to the low-level driver. * @cmd: command block we are dispatching. * * Return: nonzero return request was rejected and device's queue needs to be * plugged. */ int scsi_dispatch_cmd(struct scsi_cmnd *cmd) { struct Scsi_Host *host = cmd->device->host; unsigned long flags = 0; unsigned long timeout; int rtn = 0; atomic_inc(&cmd->device->iorequest_cnt); /* check if the device is still usable */ if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { /* in SDEV_DEL we error all commands. DID_NO_CONNECT * returns an immediate error upwards, and signals * that the device is no longer present */ cmd->result = DID_NO_CONNECT << 16; scsi_done(cmd); /* return 0 (because the command has been processed) */ goto out; } /* Check to see if the scsi lld made this device blocked. */ if (unlikely(scsi_device_blocked(cmd->device))) { /* * in blocked state, the command is just put back on * the device queue. The suspend state has already * blocked the queue so future requests should not * occur until the device transitions out of the * suspend state. */ scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n")); /* * NOTE: rtn is still zero here because we don't need the * queue to be plugged on return (it's already stopped) */ goto out; } /* * If SCSI-2 or lower, store the LUN value in cmnd. */ if (cmd->device->scsi_level <= SCSI_2 && cmd->device->scsi_level != SCSI_UNKNOWN) { cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | (cmd->device->lun << 5 & 0xe0); } /* * We will wait MIN_RESET_DELAY clock ticks after the last reset so * we can avoid the drive not being ready. */ timeout = host->last_reset + MIN_RESET_DELAY; if (host->resetting && time_before(jiffies, timeout)) { int ticks_remaining = timeout - jiffies; /* * NOTE: This may be executed from within an interrupt * handler! This is bad, but for now, it'll do. The irq * level of the interrupt handler has been masked out by the * platform dependent interrupt handling code already, so the * sti() here will not cause another call to the SCSI host's * interrupt handler (assuming there is one irq-level per * host). */ while (--ticks_remaining >= 0) mdelay(1 + 999 / HZ); host->resetting = 0; } scsi_log_send(cmd); /* * Before we queue this command, check if the command * length exceeds what the host adapter can handle. */ if (cmd->cmd_len > cmd->device->host->max_cmd_len) { SCSI_LOG_MLQUEUE(3, printk("queuecommand : command too long. " "cdb_size=%d host->max_cmd_len=%d\n", cmd->cmd_len, cmd->device->host->max_cmd_len)); cmd->result = (DID_ABORT << 16); scsi_done(cmd); goto out; } spin_lock_irqsave(host->host_lock, flags); /* * AK: unlikely race here: for some reason the timer could * expire before the serial number is set up below. * * TODO: kill serial or move to blk layer */ scsi_cmd_get_serial(host, cmd); if (unlikely(host->shost_state == SHOST_DEL)) { cmd->result = (DID_NO_CONNECT << 16); scsi_done(cmd); } else { rtn = host->hostt->queuecommand(cmd, scsi_done); } spin_unlock_irqrestore(host->host_lock, flags); if (rtn) { if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && rtn != SCSI_MLQUEUE_TARGET_BUSY) rtn = SCSI_MLQUEUE_HOST_BUSY; scsi_queue_insert(cmd, rtn); SCSI_LOG_MLQUEUE(3, printk("queuecommand : request rejected\n")); } out: SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n")); return rtn; } /** * scsi_done - Enqueue the finished SCSI command into the done queue. * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives * ownership back to SCSI Core -- i.e. the LLDD has finished with it. * * Description: This function is the mid-level's (SCSI Core) interrupt routine, * which regains ownership of the SCSI command (de facto) from a LLDD, and * enqueues the command to the done queue for further processing. * * This is the producer of the done queue who enqueues at the tail. * * This function is interrupt context safe. */ static void scsi_done(struct scsi_cmnd *cmd) { blk_complete_request(cmd->request); } /* Move this to a header if it becomes more generally useful */ static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd) { return *(struct scsi_driver **)cmd->request->rq_disk->private_data; } /** * scsi_finish_command - cleanup and pass command back to upper layer * @cmd: the command * * Description: Pass command off to upper layer for finishing of I/O * request, waking processes that are waiting on results, * etc. */ void scsi_finish_command(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct scsi_target *starget = scsi_target(sdev); struct Scsi_Host *shost = sdev->host; struct scsi_driver *drv; unsigned int good_bytes; scsi_device_unbusy(sdev); /* * Clear the flags which say that the device/host is no longer * capable of accepting new commands. These are set in scsi_queue.c * for both the queue full condition on a device, and for a * host full condition on the host. * * XXX(hch): What about locking? */ shost->host_blocked = 0; starget->target_blocked = 0; sdev->device_blocked = 0; /* * If we have valid sense information, then some kind of recovery * must have taken place. Make a note of this. */ if (SCSI_SENSE_VALID(cmd)) cmd->result |= (DRIVER_SENSE << 24); SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, "Notifying upper driver of completion " "(result %x)\n", cmd->result)); good_bytes = scsi_bufflen(cmd); if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) { int old_good_bytes = good_bytes; drv = scsi_cmd_to_driver(cmd); if (drv->done) good_bytes = drv->done(cmd); /* * USB may not give sense identifying bad sector and * simply return a residue instead, so subtract off the * residue if drv->done() error processing indicates no * change to the completion length. */ if (good_bytes == old_good_bytes) good_bytes -= scsi_get_resid(cmd); } scsi_io_completion(cmd, good_bytes); } EXPORT_SYMBOL(scsi_finish_command); /** * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth * @sdev: SCSI Device in question * @tagged: Do we use tagged queueing (non-0) or do we treat * this device as an untagged device (0) * @tags: Number of tags allowed if tagged queueing enabled, * or number of commands the low level driver can * queue up in non-tagged mode (as per cmd_per_lun). * * Returns: Nothing * * Lock Status: None held on entry * * Notes: Low level drivers may call this at any time and we will do * the right thing depending on whether or not the device is * currently active and whether or not it even has the * command blocks built yet. */ void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags) { unsigned long flags; /* * refuse to set tagged depth to an unworkable size */ if (tags <= 0) return; spin_lock_irqsave(sdev->request_queue->queue_lock, flags); /* * Check to see if the queue is managed by the block layer. * If it is, and we fail to adjust the depth, exit. * * Do not resize the tag map if it is a host wide share bqt, * because the size should be the hosts's can_queue. If there * is more IO than the LLD's can_queue (so there are not enuogh * tags) request_fn's host queue ready check will handle it. */ if (!sdev->host->bqt) { if (blk_queue_tagged(sdev->request_queue) && blk_queue_resize_tags(sdev->request_queue, tags) != 0) goto out; } sdev->queue_depth = tags; switch (tagged) { case MSG_ORDERED_TAG: sdev->ordered_tags = 1; sdev->simple_tags = 1; break; case MSG_SIMPLE_TAG: sdev->ordered_tags = 0; sdev->simple_tags = 1; break; default: sdev_printk(KERN_WARNING, sdev, "scsi_adjust_queue_depth, bad queue type, " "disabled\n"); case 0: sdev->ordered_tags = sdev->simple_tags = 0; sdev->queue_depth = tags; break; } out: spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); } EXPORT_SYMBOL(scsi_adjust_queue_depth); /** * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth * @sdev: SCSI Device in question * @depth: Current number of outstanding SCSI commands on this device, * not counting the one returned as QUEUE_FULL. * * Description: This function will track successive QUEUE_FULL events on a * specific SCSI device to determine if and when there is a * need to adjust the queue depth on the device. * * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, * -1 - Drop back to untagged operation using host->cmd_per_lun * as the untagged command depth * * Lock Status: None held on entry * * Notes: Low level drivers may call this at any time and we will do * "The Right Thing." We are interrupt context safe. */ int scsi_track_queue_full(struct scsi_device *sdev, int depth) { if ((jiffies >> 4) == sdev->last_queue_full_time) return 0; sdev->last_queue_full_time = (jiffies >> 4); if (sdev->last_queue_full_depth != depth) { sdev->last_queue_full_count = 1; sdev->last_queue_full_depth = depth; } else { sdev->last_queue_full_count++; } if (sdev->last_queue_full_count <= 10) return 0; if (sdev->last_queue_full_depth < 8) { /* Drop back to untagged */ scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun); return -1; } if (sdev->ordered_tags) scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth); else scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth); return depth; } EXPORT_SYMBOL(scsi_track_queue_full); /** * scsi_vpd_inquiry - Request a device provide us with a VPD page * @sdev: The device to ask * @buffer: Where to put the result * @page: Which Vital Product Data to return * @len: The length of the buffer * * This is an internal helper function. You probably want to use * scsi_get_vpd_page instead. * * Returns 0 on success or a negative error number. */ static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, u8 page, unsigned len) { int result; unsigned char cmd[16]; cmd[0] = INQUIRY; cmd[1] = 1; /* EVPD */ cmd[2] = page; cmd[3] = len >> 8; cmd[4] = len & 0xff; cmd[5] = 0; /* Control byte */ /* * I'm not convinced we need to try quite this hard to get VPD, but * all the existing users tried this hard. */ result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, NULL, 30 * HZ, 3, NULL); if (result) return result; /* Sanity check that we got the page back that we asked for */ if (buffer[1] != page) return -EIO; return 0; } /** * scsi_get_vpd_page - Get Vital Product Data from a SCSI device * @sdev: The device to ask * @page: Which Vital Product Data to return * * SCSI devices may optionally supply Vital Product Data. Each 'page' * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). * If the device supports this VPD page, this routine returns a pointer * to a buffer containing the data from that page. The caller is * responsible for calling kfree() on this pointer when it is no longer * needed. If we cannot retrieve the VPD page this routine returns %NULL. */ unsigned char *scsi_get_vpd_page(struct scsi_device *sdev, u8 page) { int i, result; unsigned int len; const unsigned int init_vpd_len = 255; unsigned char *buf = kmalloc(init_vpd_len, GFP_KERNEL); if (!buf) return NULL; /* Ask for all the pages supported by this device */ result = scsi_vpd_inquiry(sdev, buf, 0, init_vpd_len); if (result) goto fail; /* If the user actually wanted this page, we can skip the rest */ if (page == 0) return buf; for (i = 0; i < buf[3]; i++) if (buf[i + 4] == page) goto found; /* The device claims it doesn't support the requested page */ goto fail; found: result = scsi_vpd_inquiry(sdev, buf, page, 255); if (result) goto fail; /* * Some pages are longer than 255 bytes. The actual length of * the page is returned in the header. */ len = ((buf[2] << 8) | buf[3]) + 4; if (len <= init_vpd_len) return buf; kfree(buf); buf = kmalloc(len, GFP_KERNEL); result = scsi_vpd_inquiry(sdev, buf, page, len); if (result) goto fail; return buf; fail: kfree(buf); return NULL; } EXPORT_SYMBOL_GPL(scsi_get_vpd_page); /** * scsi_device_get - get an additional reference to a scsi_device * @sdev: device to get a reference to * * Description: Gets a reference to the scsi_device and increments the use count * of the underlying LLDD module. You must hold host_lock of the * parent Scsi_Host or already have a reference when calling this. */ int scsi_device_get(struct scsi_device *sdev) { if (sdev->sdev_state == SDEV_DEL) return -ENXIO; if (!get_device(&sdev->sdev_gendev)) return -ENXIO; /* We can fail this if we're doing SCSI operations * from module exit (like cache flush) */ try_module_get(sdev->host->hostt->module); return 0; } EXPORT_SYMBOL(scsi_device_get); /** * scsi_device_put - release a reference to a scsi_device * @sdev: device to release a reference on. * * Description: Release a reference to the scsi_device and decrements the use * count of the underlying LLDD module. The device is freed once the last * user vanishes. */ void scsi_device_put(struct scsi_device *sdev) { #ifdef CONFIG_MODULE_UNLOAD struct module *module = sdev->host->hostt->module; /* The module refcount will be zero if scsi_device_get() * was called from a module removal routine */ if (module && module_refcount(module) != 0) module_put(module); #endif put_device(&sdev->sdev_gendev); } EXPORT_SYMBOL(scsi_device_put); /* helper for shost_for_each_device, see that for documentation */ struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, struct scsi_device *prev) { struct list_head *list = (prev ? &prev->siblings : &shost->__devices); struct scsi_device *next = NULL; unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); while (list->next != &shost->__devices) { next = list_entry(list->next, struct scsi_device, siblings); /* skip devices that we can't get a reference to */ if (!scsi_device_get(next)) break; next = NULL; list = list->next; } spin_unlock_irqrestore(shost->host_lock, flags); if (prev) scsi_device_put(prev); return next; } EXPORT_SYMBOL(__scsi_iterate_devices); /** * starget_for_each_device - helper to walk all devices of a target * @starget: target whose devices we want to iterate over. * @data: Opaque passed to each function call. * @fn: Function to call on each device * * This traverses over each device of @starget. The devices have * a reference that must be released by scsi_host_put when breaking * out of the loop. */ void starget_for_each_device(struct scsi_target *starget, void *data, void (*fn)(struct scsi_device *, void *)) { struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); struct scsi_device *sdev; shost_for_each_device(sdev, shost) { if ((sdev->channel == starget->channel) && (sdev->id == starget->id)) fn(sdev, data); } } EXPORT_SYMBOL(starget_for_each_device); /** * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) * @starget: target whose devices we want to iterate over. * @data: parameter for callback @fn() * @fn: callback function that is invoked for each device * * This traverses over each device of @starget. It does _not_ * take a reference on the scsi_device, so the whole loop must be * protected by shost->host_lock. * * Note: The only reason why drivers would want to use this is because * they need to access the device list in irq context. Otherwise you * really want to use starget_for_each_device instead. **/ void __starget_for_each_device(struct scsi_target *starget, void *data, void (*fn)(struct scsi_device *, void *)) { struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); struct scsi_device *sdev; __shost_for_each_device(sdev, shost) { if ((sdev->channel == starget->channel) && (sdev->id == starget->id)) fn(sdev, data); } } EXPORT_SYMBOL(__starget_for_each_device); /** * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) * @starget: SCSI target pointer * @lun: SCSI Logical Unit Number * * Description: Looks up the scsi_device with the specified @lun for a given * @starget. The returned scsi_device does not have an additional * reference. You must hold the host's host_lock over this call and * any access to the returned scsi_device. A scsi_device in state * SDEV_DEL is skipped. * * Note: The only reason why drivers should use this is because * they need to access the device list in irq context. Otherwise you * really want to use scsi_device_lookup_by_target instead. **/ struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, uint lun) { struct scsi_device *sdev; list_for_each_entry(sdev, &starget->devices, same_target_siblings) { if (sdev->sdev_state == SDEV_DEL) continue; if (sdev->lun ==lun) return sdev; } return NULL; } EXPORT_SYMBOL(__scsi_device_lookup_by_target); /** * scsi_device_lookup_by_target - find a device given the target * @starget: SCSI target pointer * @lun: SCSI Logical Unit Number * * Description: Looks up the scsi_device with the specified @lun for a given * @starget. The returned scsi_device has an additional reference that * needs to be released with scsi_device_put once you're done with it. **/ struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, uint lun) { struct scsi_device *sdev; struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); sdev = __scsi_device_lookup_by_target(starget, lun); if (sdev && scsi_device_get(sdev)) sdev = NULL; spin_unlock_irqrestore(shost->host_lock, flags); return sdev; } EXPORT_SYMBOL(scsi_device_lookup_by_target); /** * __scsi_device_lookup - find a device given the host (UNLOCKED) * @shost: SCSI host pointer * @channel: SCSI channel (zero if only one channel) * @id: SCSI target number (physical unit number) * @lun: SCSI Logical Unit Number * * Description: Looks up the scsi_device with the specified @channel, @id, @lun * for a given host. The returned scsi_device does not have an additional * reference. You must hold the host's host_lock over this call and any access * to the returned scsi_device. * * Note: The only reason why drivers would want to use this is because * they need to access the device list in irq context. Otherwise you * really want to use scsi_device_lookup instead. **/ struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, uint channel, uint id, uint lun) { struct scsi_device *sdev; list_for_each_entry(sdev, &shost->__devices, siblings) { if (sdev->channel == channel && sdev->id == id && sdev->lun ==lun) return sdev; } return NULL; } EXPORT_SYMBOL(__scsi_device_lookup); /** * scsi_device_lookup - find a device given the host * @shost: SCSI host pointer * @channel: SCSI channel (zero if only one channel) * @id: SCSI target number (physical unit number) * @lun: SCSI Logical Unit Number * * Description: Looks up the scsi_device with the specified @channel, @id, @lun * for a given host. The returned scsi_device has an additional reference that * needs to be released with scsi_device_put once you're done with it. **/ struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, uint channel, uint id, uint lun) { struct scsi_device *sdev; unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); sdev = __scsi_device_lookup(shost, channel, id, lun); if (sdev && scsi_device_get(sdev)) sdev = NULL; spin_unlock_irqrestore(shost->host_lock, flags); return sdev; } EXPORT_SYMBOL(scsi_device_lookup); MODULE_DESCRIPTION("SCSI core"); MODULE_LICENSE("GPL"); module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); static int __init init_scsi(void) { int error; error = scsi_init_queue(); if (error) return error; error = scsi_init_procfs(); if (error) goto cleanup_queue; error = scsi_init_devinfo(); if (error) goto cleanup_procfs; error = scsi_init_hosts(); if (error) goto cleanup_devlist; error = scsi_init_sysctl(); if (error) goto cleanup_hosts; error = scsi_sysfs_register(); if (error) goto cleanup_sysctl; scsi_netlink_init(); printk(KERN_NOTICE "SCSI subsystem initialized\n"); return 0; cleanup_sysctl: scsi_exit_sysctl(); cleanup_hosts: scsi_exit_hosts(); cleanup_devlist: scsi_exit_devinfo(); cleanup_procfs: scsi_exit_procfs(); cleanup_queue: scsi_exit_queue(); printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", -error); return error; } static void __exit exit_scsi(void) { scsi_netlink_exit(); scsi_sysfs_unregister(); scsi_exit_sysctl(); scsi_exit_hosts(); scsi_exit_devinfo(); scsi_exit_procfs(); scsi_exit_queue(); } subsys_initcall(init_scsi); module_exit(exit_scsi);