/* * 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) /* * Macro to determine the size of SCSI command. This macro takes vendor * unique commands into account. SCSI commands in groups 6 and 7 are * vendor unique and we will depend upon the command length being * supplied correctly in cmd_len. */ #define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \ COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len) /* * 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 ", }; 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 *slab; unsigned int users; char *name; unsigned int slab_flags; gfp_t gfp_mask; }; static struct scsi_host_cmd_pool scsi_cmd_pool = { .name = "scsi_cmd_cache", .slab_flags = SLAB_HWCACHE_ALIGN, }; static struct scsi_host_cmd_pool scsi_cmd_dma_pool = { .name = "scsi_cmd_cache(DMA)", .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA, .gfp_mask = __GFP_DMA, }; static DEFINE_MUTEX(host_cmd_pool_mutex); struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask) { struct scsi_cmnd *cmd; cmd = kmem_cache_alloc(shost->cmd_pool->slab, gfp_mask | shost->cmd_pool->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); } return cmd; } EXPORT_SYMBOL_GPL(__scsi_get_command); /* * Function: scsi_get_command() * * Purpose: Allocate and setup a scsi command block * * Arguments: 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; memset(cmd, 0, sizeof(*cmd)); cmd->device = dev; init_timer(&cmd->eh_timeout); 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); 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)) kmem_cache_free(shost->cmd_pool->slab, cmd); put_device(dev); } EXPORT_SYMBOL(__scsi_put_command); /* * Function: scsi_put_command() * * Purpose: Free a scsi command block * * Arguments: 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); /* * Function: scsi_setup_command_freelist() * * Purpose: Setup the command freelist for a scsi host. * * Arguments: shost - host to allocate the freelist for. * * Returns: Nothing. */ int scsi_setup_command_freelist(struct Scsi_Host *shost) { struct scsi_host_cmd_pool *pool; struct scsi_cmnd *cmd; spin_lock_init(&shost->free_list_lock); INIT_LIST_HEAD(&shost->free_list); /* * Select a command slab for this host and create it if not * yet existant. */ mutex_lock(&host_cmd_pool_mutex); pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool); if (!pool->users) { pool->slab = kmem_cache_create(pool->name, sizeof(struct scsi_cmnd), 0, pool->slab_flags, NULL); if (!pool->slab) goto fail; } pool->users++; shost->cmd_pool = pool; mutex_unlock(&host_cmd_pool_mutex); /* * Get one backup command for this host. */ cmd = kmem_cache_alloc(shost->cmd_pool->slab, GFP_KERNEL | shost->cmd_pool->gfp_mask); if (!cmd) goto fail2; list_add(&cmd->list, &shost->free_list); return 0; fail2: if (!--pool->users) kmem_cache_destroy(pool->slab); return -ENOMEM; fail: mutex_unlock(&host_cmd_pool_mutex); return -ENOMEM; } /* * Function: scsi_destroy_command_freelist() * * Purpose: Release the command freelist for a scsi host. * * Arguments: shost - host that's freelist is going to be destroyed */ void scsi_destroy_command_freelist(struct Scsi_Host *shost) { 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); kmem_cache_free(shost->cmd_pool->slab, cmd); } mutex_lock(&host_cmd_pool_mutex); if (!--shost->cmd_pool->users) kmem_cache_destroy(shost->cmd_pool->slab); mutex_unlock(&host_cmd_pool_mutex); } #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 /* * Assign a serial number to the 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++; } /* * Function: scsi_dispatch_command * * Purpose: Dispatch a command to the low-level driver. * * Arguments: cmd - command block we are dispatching. * * Notes: */ 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; /* 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; atomic_inc(&cmd->device->iorequest_cnt); __scsi_done(cmd); /* return 0 (because the command has been processed) */ goto out; } /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */ if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) { /* * in SDEV_BLOCK, 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; } /* * AK: unlikely race here: for some reason the timer could * expire before the serial number is set up below. */ scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out); scsi_log_send(cmd); /* * We will use a queued command if possible, otherwise we will * emulate the queuing and calling of completion function ourselves. */ atomic_inc(&cmd->device->iorequest_cnt); /* * Before we queue this command, check if the command * length exceeds what the host adapter can handle. */ if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) { SCSI_LOG_MLQUEUE(3, printk("queuecommand : command too long.\n")); cmd->result = (DID_ABORT << 16); scsi_done(cmd); goto out; } spin_lock_irqsave(host->host_lock, flags); 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 (scsi_delete_timer(cmd)) { atomic_inc(&cmd->device->iodone_cnt); scsi_queue_insert(cmd, (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ? rtn : SCSI_MLQUEUE_HOST_BUSY); } SCSI_LOG_MLQUEUE(3, printk("queuecommand : request rejected\n")); } out: SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n")); return rtn; } /** * scsi_req_abort_cmd -- Request command recovery for the specified command * cmd: pointer to the SCSI command of interest * * This function requests that SCSI Core start recovery for the * command by deleting the timer and adding the command to the eh * queue. It can be called by either LLDDs or SCSI Core. LLDDs who * implement their own error recovery MAY ignore the timeout event if * they generated scsi_req_abort_cmd. */ void scsi_req_abort_cmd(struct scsi_cmnd *cmd) { if (!scsi_delete_timer(cmd)) return; scsi_times_out(cmd); } EXPORT_SYMBOL(scsi_req_abort_cmd); /** * 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. * * 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) { /* * We don't have to worry about this one timing out any more. * If we are unable to remove the timer, then the command * has already timed out. In which case, we have no choice but to * let the timeout function run, as we have no idea where in fact * that function could really be. It might be on another processor, * etc, etc. */ if (!scsi_delete_timer(cmd)) return; __scsi_done(cmd); } /* Private entry to scsi_done() to complete a command when the timer * isn't running --- used by scsi_times_out */ void __scsi_done(struct scsi_cmnd *cmd) { struct request *rq = cmd->request; /* * Set the serial numbers back to zero */ cmd->serial_number = 0; atomic_inc(&cmd->device->iodone_cnt); if (cmd->result) atomic_inc(&cmd->device->ioerr_cnt); BUG_ON(!rq); /* * The uptodate/nbytes values don't matter, as we allow partial * completes and thus will check this in the softirq callback */ rq->completion_data = cmd; blk_complete_request(rq); } /* 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; } /* * Function: scsi_finish_command * * Purpose: 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_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; 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 = cmd->request_bufflen; if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) { drv = scsi_cmd_to_driver(cmd); if (drv->done) good_bytes = drv->done(cmd); } scsi_io_completion(cmd, good_bytes); } EXPORT_SYMBOL(scsi_finish_command); /* * Function: scsi_adjust_queue_depth() * * Purpose: Allow low level drivers to tell us to change the queue depth * on a specific SCSI device * * Arguments: 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 */ 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); /* * Function: scsi_track_queue_full() * * Purpose: 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. * * Arguments: sdev - SCSI Device in question * depth - Current number of outstanding SCSI commands on * this device, not counting the one returned as * QUEUE_FULL. * * 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_device_get - get an addition reference to a scsi_device * @sdev: device to get a reference to * * 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. * * 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, thus not documented */ 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. * * This traverses over each devices of @shost. 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); /** * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) * @starget: SCSI target pointer * @lun: SCSI Logical Unit Number * * Looks up the scsi_device with the specified @lun for a give * @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. * * Note: The only reason why drivers would want to use this is because * they're 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->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 * * Looks up the scsi_device with the specified @channel, @id, @lun for a * give host. The returned scsi_device has an additional reference that * needs to be release with scsi_host_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) * @pun: SCSI target number (physical unit number) * @lun: SCSI Logical Unit Number * * Looks up the scsi_device with the specified @channel, @id, @lun for a * give 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're 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 * * Looks up the scsi_device with the specified @channel, @id, @lun for a * give host. The returned scsi_device has an additional reference that * needs to be release with scsi_host_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);