| /* |
| * 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_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," |
| " done = 0x%p, queuecommand 0x%p\n", |
| scsi_sglist(cmd), scsi_bufflen(cmd), |
| cmd->done, |
| 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); |
| } |
| |
| /* |
| * 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; |
| |
| 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)); |
| |
| cmd->done(cmd); |
| } |
| 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 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. |
| * |
| * 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 |
| * |
| * 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); |