diff options
Diffstat (limited to 'drivers/scsi/scsi.c')
| -rw-r--r-- | drivers/scsi/scsi.c | 1375 |
1 files changed, 1375 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c new file mode 100644 index 00000000000..2e7ab3ab099 --- /dev/null +++ b/drivers/scsi/scsi.c @@ -0,0 +1,1375 @@ +/* + * 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/sched.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/devfs_fs_kernel.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 <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/scsi_request.h> + +#include "scsi_priv.h" +#include "scsi_logging.h" + + +/* + * 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 + +const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] = { + "Direct-Access ", + "Sequential-Access", + "Printer ", + "Processor ", + "WORM ", + "CD-ROM ", + "Scanner ", + "Optical Device ", + "Medium Changer ", + "Communications ", + "Unknown ", + "Unknown ", + "RAID ", + "Enclosure ", +}; +EXPORT_SYMBOL(scsi_device_types); + +/* + * Function: scsi_allocate_request + * + * Purpose: Allocate a request descriptor. + * + * Arguments: device - device for which we want a request + * gfp_mask - allocation flags passed to kmalloc + * + * Lock status: No locks assumed to be held. This function is SMP-safe. + * + * Returns: Pointer to request block. + */ +struct scsi_request *scsi_allocate_request(struct scsi_device *sdev, + int gfp_mask) +{ + const int offset = ALIGN(sizeof(struct scsi_request), 4); + const int size = offset + sizeof(struct request); + struct scsi_request *sreq; + + sreq = kmalloc(size, gfp_mask); + if (likely(sreq != NULL)) { + memset(sreq, 0, size); + sreq->sr_request = (struct request *)(((char *)sreq) + offset); + sreq->sr_device = sdev; + sreq->sr_host = sdev->host; + sreq->sr_magic = SCSI_REQ_MAGIC; + sreq->sr_data_direction = DMA_BIDIRECTIONAL; + } + + return sreq; +} +EXPORT_SYMBOL(scsi_allocate_request); + +void __scsi_release_request(struct scsi_request *sreq) +{ + struct request *req = sreq->sr_request; + + /* unlikely because the tag was usually ended earlier by the + * mid-layer. However, for layering reasons ULD's don't end + * the tag of commands they generate. */ + if (unlikely(blk_rq_tagged(req))) { + unsigned long flags; + struct request_queue *q = req->q; + + spin_lock_irqsave(q->queue_lock, flags); + blk_queue_end_tag(q, req); + spin_unlock_irqrestore(q->queue_lock, flags); + } + + + if (likely(sreq->sr_command != NULL)) { + struct scsi_cmnd *cmd = sreq->sr_command; + + sreq->sr_command = NULL; + scsi_next_command(cmd); + } +} + +/* + * Function: scsi_release_request + * + * Purpose: Release a request descriptor. + * + * Arguments: sreq - request to release + * + * Lock status: No locks assumed to be held. This function is SMP-safe. + */ +void scsi_release_request(struct scsi_request *sreq) +{ + __scsi_release_request(sreq); + kfree(sreq); +} +EXPORT_SYMBOL(scsi_release_request); + +struct scsi_host_cmd_pool { + kmem_cache_t *slab; + unsigned int users; + char *name; + unsigned int slab_flags; + unsigned int 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 DECLARE_MUTEX(host_cmd_pool_mutex); + +static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, + int 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; +} + +/* + * 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, int 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; + cmd->state = SCSI_STATE_UNUSED; + cmd->owner = SCSI_OWNER_NOBODY; + 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); + } else + put_device(&dev->sdev_gendev); + + return cmd; +} +EXPORT_SYMBOL(scsi_get_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; + struct Scsi_Host *shost = sdev->host; + 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(&cmd->device->list_lock); + /* changing locks here, don't need to restore the irq state */ + spin_lock(&shost->free_list_lock); + 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(&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. + */ + down(&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, NULL); + if (!pool->slab) + goto fail; + } + + pool->users++; + shost->cmd_pool = pool; + up(&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: + up(&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); + } + + down(&host_cmd_pool_mutex); + if (!--shost->cmd_pool->users) + kmem_cache_destroy(shost->cmd_pool->slab); + up(&host_cmd_pool_mutex); +} + +#ifdef CONFIG_SCSI_LOGGING +void scsi_log_send(struct scsi_cmnd *cmd) +{ + unsigned int level; + struct scsi_device *sdev; + + /* + * 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) { + sdev = cmd->device; + printk(KERN_INFO "scsi <%d:%d:%d:%d> send ", + sdev->host->host_no, sdev->channel, sdev->id, + sdev->lun); + if (level > 2) + printk("0x%p ", cmd); + /* + * spaces to match disposition and cmd->result + * output in scsi_log_completion. + */ + printk(" "); + scsi_print_command(cmd); + if (level > 3) { + printk(KERN_INFO "buffer = 0x%p, bufflen = %d," + " done = 0x%p, queuecommand 0x%p\n", + cmd->buffer, cmd->bufflen, + cmd->done, + sdev->host->hostt->queuecommand); + + } + } + } +} + +void scsi_log_completion(struct scsi_cmnd *cmd, int disposition) +{ + unsigned int level; + struct scsi_device *sdev; + + /* + * 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)) { + sdev = cmd->device; + printk(KERN_INFO "scsi <%d:%d:%d:%d> done ", + sdev->host->host_no, sdev->channel, sdev->id, + sdev->lun); + if (level > 2) + printk("0x%p ", cmd); + /* + * Dump truncated values, so we usually fit within + * 80 chars. + */ + switch (disposition) { + case SUCCESS: + printk("SUCCESS"); + break; + case NEEDS_RETRY: + printk("RETRY "); + break; + case ADD_TO_MLQUEUE: + printk("MLQUEUE"); + break; + case FAILED: + printk("FAILED "); + break; + case TIMEOUT_ERROR: + /* + * If called via scsi_times_out. + */ + printk("TIMEOUT"); + break; + default: + printk("UNKNOWN"); + } + printk(" %8x ", cmd->result); + scsi_print_command(cmd); + if (status_byte(cmd->result) & CHECK_CONDITION) { + /* + * XXX The print_sense formatting/prefix + * doesn't match this function. + */ + scsi_print_sense("", cmd); + } + if (level > 3) { + printk(KERN_INFO "scsi host busy %d failed %d\n", + sdev->host->host_busy, + sdev->host->host_failed); + } + } + } +} +#endif + +/* + * Assign a serial number and pid 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++; + + cmd->pid = host->cmd_pid++; + if (cmd->pid == 0) + cmd->pid = host->cmd_pid++; +} + +/* + * 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->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. + */ + + cmd->state = SCSI_STATE_QUEUED; + cmd->owner = SCSI_OWNER_LOWLEVEL; + + 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(test_bit(SHOST_CANCEL, &host->shost_state))) { + 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) { + 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; +} + +/* + * Function: scsi_init_cmd_from_req + * + * Purpose: Queue a SCSI command + * Purpose: Initialize a struct scsi_cmnd from a struct scsi_request + * + * Arguments: cmd - command descriptor. + * sreq - Request from the queue. + * + * Lock status: None needed. + * + * Returns: Nothing. + * + * Notes: Mainly transfer data from the request structure to the + * command structure. The request structure is allocated + * using the normal memory allocator, and requests can pile + * up to more or less any depth. The command structure represents + * a consumable resource, as these are allocated into a pool + * when the SCSI subsystem initializes. The preallocation is + * required so that in low-memory situations a disk I/O request + * won't cause the memory manager to try and write out a page. + * The request structure is generally used by ioctls and character + * devices. + */ +void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq) +{ + sreq->sr_command = cmd; + + cmd->owner = SCSI_OWNER_MIDLEVEL; + cmd->cmd_len = sreq->sr_cmd_len; + cmd->use_sg = sreq->sr_use_sg; + + cmd->request = sreq->sr_request; + memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd)); + cmd->serial_number = 0; + cmd->serial_number_at_timeout = 0; + cmd->bufflen = sreq->sr_bufflen; + cmd->buffer = sreq->sr_buffer; + cmd->retries = 0; + cmd->allowed = sreq->sr_allowed; + cmd->done = sreq->sr_done; + cmd->timeout_per_command = sreq->sr_timeout_per_command; + cmd->sc_data_direction = sreq->sr_data_direction; + cmd->sglist_len = sreq->sr_sglist_len; + cmd->underflow = sreq->sr_underflow; + cmd->sc_request = sreq; + memcpy(cmd->cmnd, sreq->sr_cmnd, sizeof(sreq->sr_cmnd)); + + /* + * Zero the sense buffer. Some host adapters automatically request + * sense on error. 0 is not a valid sense code. + */ + memset(cmd->sense_buffer, 0, sizeof(sreq->sr_sense_buffer)); + cmd->request_buffer = sreq->sr_buffer; + cmd->request_bufflen = sreq->sr_bufflen; + cmd->old_use_sg = cmd->use_sg; + if (cmd->cmd_len == 0) + cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); + cmd->old_cmd_len = cmd->cmd_len; + cmd->sc_old_data_direction = cmd->sc_data_direction; + cmd->old_underflow = cmd->underflow; + + /* + * Start the timer ticking. + */ + cmd->internal_timeout = NORMAL_TIMEOUT; + cmd->abort_reason = 0; + cmd->result = 0; + + SCSI_LOG_MLQUEUE(3, printk("Leaving scsi_init_cmd_from_req()\n")); +} + +/* + * Per-CPU I/O completion queue. + */ +static DEFINE_PER_CPU(struct list_head, scsi_done_q); + +/** + * 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. + */ +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) +{ + unsigned long flags; + + /* + * Set the serial numbers back to zero + */ + cmd->serial_number = 0; + cmd->serial_number_at_timeout = 0; + cmd->state = SCSI_STATE_BHQUEUE; + cmd->owner = SCSI_OWNER_BH_HANDLER; + + atomic_inc(&cmd->device->iodone_cnt); + if (cmd->result) + atomic_inc(&cmd->device->ioerr_cnt); + + /* + * Next, enqueue the command into the done queue. + * It is a per-CPU queue, so we just disable local interrupts + * and need no spinlock. + */ + local_irq_save(flags); + list_add_tail(&cmd->eh_entry, &__get_cpu_var(scsi_done_q)); + raise_softirq_irqoff(SCSI_SOFTIRQ); + local_irq_restore(flags); +} + +/** + * scsi_softirq - Perform post-interrupt processing of finished SCSI commands. + * + * This is the consumer of the done queue. + * + * This is called with all interrupts enabled. This should reduce + * interrupt latency, stack depth, and reentrancy of the low-level + * drivers. + */ +static void scsi_softirq(struct softirq_action *h) +{ + int disposition; + LIST_HEAD(local_q); + + local_irq_disable(); + list_splice_init(&__get_cpu_var(scsi_done_q), &local_q); + local_irq_enable(); + + while (!list_empty(&local_q)) { + struct scsi_cmnd *cmd = list_entry(local_q.next, + struct scsi_cmnd, eh_entry); + list_del_init(&cmd->eh_entry); + + disposition = scsi_decide_disposition(cmd); + scsi_log_completion(cmd, disposition); + switch (disposition) { + case SUCCESS: + scsi_finish_command(cmd); + break; + case NEEDS_RETRY: + scsi_retry_command(cmd); + break; + case ADD_TO_MLQUEUE: + scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); + break; + default: + if (!scsi_eh_scmd_add(cmd, 0)) + scsi_finish_command(cmd); + } + } +} + +/* + * Function: scsi_retry_command + * + * Purpose: Send a command back to the low level to be retried. + * + * Notes: This command is always executed in the context of the + * bottom half handler, or the error handler thread. Low + * level drivers should not become re-entrant as a result of + * this. + */ +int scsi_retry_command(struct scsi_cmnd *cmd) +{ + /* + * Restore the SCSI command state. + */ + scsi_setup_cmd_retry(cmd); + + /* + * Zero the sense information from the last time we tried + * this command. + */ + memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer)); + + return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); +} + +/* + * 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_request *sreq; + + 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, printk("Notifying upper driver of completion " + "for device %d %x\n", sdev->id, cmd->result)); + + cmd->owner = SCSI_OWNER_HIGHLEVEL; + cmd->state = SCSI_STATE_FINISHED; + + /* + * We can get here with use_sg=0, causing a panic in the upper level + */ + cmd->use_sg = cmd->old_use_sg; + + /* + * If there is an associated request structure, copy the data over + * before we call the completion function. + */ + sreq = cmd->sc_request; + if (sreq) { + sreq->sr_result = sreq->sr_command->result; + if (sreq->sr_result) { + memcpy(sreq->sr_sense_buffer, + sreq->sr_command->sense_buffer, + sizeof(sreq->sr_sense_buffer)); + } + } + + 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: + printk(KERN_WARNING "(scsi%d:%d:%d:%d) " + "scsi_adjust_queue_depth, bad queue type, " + "disabled\n", sdev->host->host_no, + sdev->channel, sdev->id, sdev->lun); + 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 || sdev->sdev_state == SDEV_CANCEL) + return -ENXIO; + if (!get_device(&sdev->sdev_gendev)) + return -ENXIO; + if (!try_module_get(sdev->host->hostt->module)) { + put_device(&sdev->sdev_gendev); + return -ENXIO; + } + 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) +{ + module_put(sdev->host->hostt->module); + 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); + +/** + * scsi_device_cancel - cancel outstanding IO to this device + * @sdev: Pointer to struct scsi_device + * @recovery: Boolean instructing function to recover device or not. + * + **/ +int scsi_device_cancel(struct scsi_device *sdev, int recovery) +{ + struct scsi_cmnd *scmd; + LIST_HEAD(active_list); + struct list_head *lh, *lh_sf; + unsigned long flags; + + scsi_device_set_state(sdev, SDEV_CANCEL); + + spin_lock_irqsave(&sdev->list_lock, flags); + list_for_each_entry(scmd, &sdev->cmd_list, list) { + if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) { + /* + * If we are unable to remove the timer, it means + * that the command has already timed out or + * finished. + */ + if (!scsi_delete_timer(scmd)) + continue; + list_add_tail(&scmd->eh_entry, &active_list); + } + } + spin_unlock_irqrestore(&sdev->list_lock, flags); + + if (!list_empty(&active_list)) { + list_for_each_safe(lh, lh_sf, &active_list) { + scmd = list_entry(lh, struct scsi_cmnd, eh_entry); + list_del_init(lh); + if (recovery) { + scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD); + } else { + scmd->result = (DID_ABORT << 16); + scsi_finish_command(scmd); + } + } + } + + return 0; +} +EXPORT_SYMBOL(scsi_device_cancel); + +#ifdef CONFIG_HOTPLUG_CPU +static int scsi_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + int cpu = (unsigned long)hcpu; + + switch(action) { + case CPU_DEAD: + /* Drain scsi_done_q. */ + local_irq_disable(); + list_splice_init(&per_cpu(scsi_done_q, cpu), + &__get_cpu_var(scsi_done_q)); + raise_softirq_irqoff(SCSI_SOFTIRQ); + local_irq_enable(); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block __devinitdata scsi_cpu_nb = { + .notifier_call = scsi_cpu_notify, +}; + +#define register_scsi_cpu() register_cpu_notifier(&scsi_cpu_nb) +#define unregister_scsi_cpu() unregister_cpu_notifier(&scsi_cpu_nb) +#else +#define register_scsi_cpu() +#define unregister_scsi_cpu() +#endif /* CONFIG_HOTPLUG_CPU */ + +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, i; + + 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; + + for (i = 0; i < NR_CPUS; i++) + INIT_LIST_HEAD(&per_cpu(scsi_done_q, i)); + + devfs_mk_dir("scsi"); + open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL); + register_scsi_cpu(); + 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_sysfs_unregister(); + scsi_exit_sysctl(); + scsi_exit_hosts(); + scsi_exit_devinfo(); + devfs_remove("scsi"); + scsi_exit_procfs(); + scsi_exit_queue(); + unregister_scsi_cpu(); +} + +subsys_initcall(init_scsi); +module_exit(exit_scsi); |