diff options
Diffstat (limited to 'drivers/scsi/scsi.c')
| -rw-r--r-- | drivers/scsi/scsi.c | 858 |
1 files changed, 858 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c new file mode 100644 index 000000000..3cda5d26b --- /dev/null +++ b/drivers/scsi/scsi.c @@ -0,0 +1,858 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 <asm/unaligned.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" + +#define CREATE_TRACE_POINTS +#include <trace/events/scsi.h> + +/* + * Definitions and constants. + */ + +/* + * 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 + +#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 + cmd address + * + * 3: same as 2 + * + * 4: same as 3 + */ + 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: scmd 0x%p\n", cmd); + scsi_print_command(cmd); + } + } +} + +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 + * + * 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)) { + scsi_print_result(cmd, "Done", disposition); + scsi_print_command(cmd); + if (scsi_status_is_check_condition(cmd->result)) + scsi_print_sense(cmd); + if (level > 3) + scmd_printk(KERN_INFO, cmd, + "scsi host busy %d failed %d\n", + scsi_host_busy(cmd->device->host), + cmd->device->host->host_failed); + } + } +} +#endif + +/** + * scsi_finish_command - cleanup and pass command back to upper layer + * @cmd: the command + * + * Description: Pass command off to upper layer for finishing of I/O + * request, waking processes that are waiting on results, + * etc. + */ +void scsi_finish_command(struct scsi_cmnd *cmd) +{ + struct scsi_device *sdev = cmd->device; + struct scsi_target *starget = scsi_target(sdev); + struct Scsi_Host *shost = sdev->host; + struct scsi_driver *drv; + unsigned int good_bytes; + + scsi_device_unbusy(sdev, cmd); + + /* + * Clear the flags that say that the device/target/host is no longer + * capable of accepting new commands. + */ + if (atomic_read(&shost->host_blocked)) + atomic_set(&shost->host_blocked, 0); + if (atomic_read(&starget->target_blocked)) + atomic_set(&starget->target_blocked, 0); + if (atomic_read(&sdev->device_blocked)) + atomic_set(&sdev->device_blocked, 0); + + SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, + "Notifying upper driver of completion " + "(result %x)\n", cmd->result)); + + good_bytes = scsi_bufflen(cmd); + if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { + int old_good_bytes = good_bytes; + drv = scsi_cmd_to_driver(cmd); + if (drv->done) + good_bytes = drv->done(cmd); + /* + * USB may not give sense identifying bad sector and + * simply return a residue instead, so subtract off the + * residue if drv->done() error processing indicates no + * change to the completion length. + */ + if (good_bytes == old_good_bytes) + good_bytes -= scsi_get_resid(cmd); + } + scsi_io_completion(cmd, good_bytes); +} + + +/* + * 4096 is big enough for saturating fast SCSI LUNs. + */ +int scsi_device_max_queue_depth(struct scsi_device *sdev) +{ + return min_t(int, sdev->host->can_queue, 4096); +} + +/** + * scsi_change_queue_depth - change a device's queue depth + * @sdev: SCSI Device in question + * @depth: number of commands allowed to be queued to the driver + * + * Sets the device queue depth and returns the new value. + */ +int scsi_change_queue_depth(struct scsi_device *sdev, int depth) +{ + depth = min_t(int, depth, scsi_device_max_queue_depth(sdev)); + + if (depth > 0) { + sdev->queue_depth = depth; + wmb(); + } + + if (sdev->request_queue) + blk_set_queue_depth(sdev->request_queue, depth); + + sbitmap_resize(&sdev->budget_map, sdev->queue_depth); + + return sdev->queue_depth; +} +EXPORT_SYMBOL(scsi_change_queue_depth); + +/** + * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth + * @sdev: SCSI Device in question + * @depth: Current number of outstanding SCSI commands on this device, + * not counting the one returned as QUEUE_FULL. + * + * Description: This function will track successive QUEUE_FULL events on a + * specific SCSI device to determine if and when there is a + * need to adjust the queue depth on the device. + * + * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, + * -1 - Drop back to untagged operation using host->cmd_per_lun + * as the untagged command depth + * + * Lock Status: None held on entry + * + * Notes: Low level drivers may call this at any time and we will do + * "The Right Thing." We are interrupt context safe. + */ +int scsi_track_queue_full(struct scsi_device *sdev, int depth) +{ + + /* + * Don't let QUEUE_FULLs on the same + * jiffies count, they could all be from + * same event. + */ + if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) + return 0; + + sdev->last_queue_full_time = jiffies; + 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; + + return scsi_change_queue_depth(sdev, depth); +} +EXPORT_SYMBOL(scsi_track_queue_full); + +/** + * scsi_vpd_inquiry - Request a device provide us with a VPD page + * @sdev: The device to ask + * @buffer: Where to put the result + * @page: Which Vital Product Data to return + * @len: The length of the buffer + * + * This is an internal helper function. You probably want to use + * scsi_get_vpd_page instead. + * + * Returns size of the vpd page on success or a negative error number. + */ +static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, + u8 page, unsigned len) +{ + int result; + unsigned char cmd[16]; + + if (len < 4) + return -EINVAL; + + cmd[0] = INQUIRY; + cmd[1] = 1; /* EVPD */ + cmd[2] = page; + cmd[3] = len >> 8; + cmd[4] = len & 0xff; + cmd[5] = 0; /* Control byte */ + + /* + * I'm not convinced we need to try quite this hard to get VPD, but + * all the existing users tried this hard. + */ + result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, + len, NULL, 30 * HZ, 3, NULL); + if (result) + return -EIO; + + /* + * Sanity check that we got the page back that we asked for and that + * the page size is not 0. + */ + if (buffer[1] != page) + return -EIO; + + result = get_unaligned_be16(&buffer[2]); + if (!result) + return -EIO; + + return result + 4; +} + +static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page) +{ + unsigned char vpd_header[SCSI_VPD_HEADER_SIZE] __aligned(4); + int result; + + if (sdev->no_vpd_size) + return SCSI_DEFAULT_VPD_LEN; + + /* + * Fetch the VPD page header to find out how big the page + * is. This is done to prevent problems on legacy devices + * which can not handle allocation lengths as large as + * potentially requested by the caller. + */ + result = scsi_vpd_inquiry(sdev, vpd_header, page, sizeof(vpd_header)); + if (result < 0) + return 0; + + if (result < SCSI_VPD_HEADER_SIZE) { + dev_warn_once(&sdev->sdev_gendev, + "%s: short VPD page 0x%02x length: %d bytes\n", + __func__, page, result); + return 0; + } + + return result; +} + +/** + * scsi_get_vpd_page - Get Vital Product Data from a SCSI device + * @sdev: The device to ask + * @page: Which Vital Product Data to return + * @buf: where to store the VPD + * @buf_len: number of bytes in the VPD buffer area + * + * SCSI devices may optionally supply Vital Product Data. Each 'page' + * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). + * If the device supports this VPD page, this routine fills @buf + * with the data from that page and return 0. If the VPD page is not + * supported or its content cannot be retrieved, -EINVAL is returned. + */ +int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, + int buf_len) +{ + int result, vpd_len; + + if (!scsi_device_supports_vpd(sdev)) + return -EINVAL; + + vpd_len = scsi_get_vpd_size(sdev, page); + if (vpd_len <= 0) + return -EINVAL; + + vpd_len = min(vpd_len, buf_len); + + /* + * Fetch the actual page. Since the appropriate size was reported + * by the device it is now safe to ask for something bigger. + */ + memset(buf, 0, buf_len); + result = scsi_vpd_inquiry(sdev, buf, page, vpd_len); + if (result < 0) + return -EINVAL; + else if (result > vpd_len) + dev_warn_once(&sdev->sdev_gendev, + "%s: VPD page 0x%02x result %d > %d bytes\n", + __func__, page, result, vpd_len); + + return 0; +} +EXPORT_SYMBOL_GPL(scsi_get_vpd_page); + +/** + * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device + * @sdev: The device to ask + * @page: Which Vital Product Data to return + * + * Returns %NULL upon failure. + */ +static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) +{ + struct scsi_vpd *vpd_buf; + int vpd_len, result; + + vpd_len = scsi_get_vpd_size(sdev, page); + if (vpd_len <= 0) + return NULL; + +retry_pg: + /* + * Fetch the actual page. Since the appropriate size was reported + * by the device it is now safe to ask for something bigger. + */ + vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); + if (!vpd_buf) + return NULL; + + result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); + if (result < 0) { + kfree(vpd_buf); + return NULL; + } + if (result > vpd_len) { + dev_warn_once(&sdev->sdev_gendev, + "%s: VPD page 0x%02x result %d > %d bytes\n", + __func__, page, result, vpd_len); + vpd_len = result; + kfree(vpd_buf); + goto retry_pg; + } + + vpd_buf->len = result; + + return vpd_buf; +} + +static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, + struct scsi_vpd __rcu **sdev_vpd_buf) +{ + struct scsi_vpd *vpd_buf; + + vpd_buf = scsi_get_vpd_buf(sdev, page); + if (!vpd_buf) + return; + + mutex_lock(&sdev->inquiry_mutex); + vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf, + lockdep_is_held(&sdev->inquiry_mutex)); + mutex_unlock(&sdev->inquiry_mutex); + + if (vpd_buf) + kfree_rcu(vpd_buf, rcu); +} + +/** + * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure + * @sdev: The device to ask + * + * Attach the 'Device Identification' VPD page (0x83) and the + * 'Unit Serial Number' VPD page (0x80) to a SCSI device + * structure. This information can be used to identify the device + * uniquely. + */ +void scsi_attach_vpd(struct scsi_device *sdev) +{ + int i; + struct scsi_vpd *vpd_buf; + + if (!scsi_device_supports_vpd(sdev)) + return; + + /* Ask for all the pages supported by this device */ + vpd_buf = scsi_get_vpd_buf(sdev, 0); + if (!vpd_buf) + return; + + for (i = 4; i < vpd_buf->len; i++) { + if (vpd_buf->data[i] == 0x0) + scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0); + if (vpd_buf->data[i] == 0x80) + scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); + if (vpd_buf->data[i] == 0x83) + scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); + if (vpd_buf->data[i] == 0x89) + scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89); + if (vpd_buf->data[i] == 0xb0) + scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0); + if (vpd_buf->data[i] == 0xb1) + scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1); + if (vpd_buf->data[i] == 0xb2) + scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2); + } + kfree(vpd_buf); +} + +/** + * scsi_report_opcode - Find out if a given command opcode is supported + * @sdev: scsi device to query + * @buffer: scratch buffer (must be at least 20 bytes long) + * @len: length of buffer + * @opcode: opcode for command to look up + * + * Uses the REPORT SUPPORTED OPERATION CODES to look up the given + * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is + * unsupported and 1 if the device claims to support the command. + */ +int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, + unsigned int len, unsigned char opcode) +{ + unsigned char cmd[16]; + struct scsi_sense_hdr sshdr; + int result, request_len; + + if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) + return -EINVAL; + + /* RSOC header + size of command we are asking about */ + request_len = 4 + COMMAND_SIZE(opcode); + if (request_len > len) { + dev_warn_once(&sdev->sdev_gendev, + "%s: len %u bytes, opcode 0x%02x needs %u\n", + __func__, len, opcode, request_len); + return -EINVAL; + } + + memset(cmd, 0, 16); + cmd[0] = MAINTENANCE_IN; + cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; + cmd[2] = 1; /* One command format */ + cmd[3] = opcode; + put_unaligned_be32(request_len, &cmd[6]); + memset(buffer, 0, len); + + result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, + request_len, &sshdr, 30 * HZ, 3, NULL); + + if (result < 0) + return result; + if (result && scsi_sense_valid(&sshdr) && + sshdr.sense_key == ILLEGAL_REQUEST && + (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) + return -EINVAL; + + if ((buffer[1] & 3) == 3) /* Command supported */ + return 1; + + return 0; +} +EXPORT_SYMBOL(scsi_report_opcode); + +/** + * scsi_device_get - get an additional reference to a scsi_device + * @sdev: device to get a reference to + * + * Description: Gets a reference to the scsi_device and increments the use count + * of the underlying LLDD module. You must hold host_lock of the + * parent Scsi_Host or already have a reference when calling this. + * + * This will fail if a device is deleted or cancelled, or when the LLD module + * is in the process of being unloaded. + */ +int scsi_device_get(struct scsi_device *sdev) +{ + if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) + goto fail; + if (!get_device(&sdev->sdev_gendev)) + goto fail; + if (!try_module_get(sdev->host->hostt->module)) + goto fail_put_device; + return 0; + +fail_put_device: + put_device(&sdev->sdev_gendev); +fail: + return -ENXIO; +} +EXPORT_SYMBOL(scsi_device_get); + +/** + * scsi_device_put - release a reference to a scsi_device + * @sdev: device to release a reference on. + * + * Description: Release a reference to the scsi_device and decrements the use + * count of the underlying LLDD module. The device is freed once the last + * user vanishes. + */ +void scsi_device_put(struct scsi_device *sdev) +{ + struct module *mod = sdev->host->hostt->module; + + put_device(&sdev->sdev_gendev); + module_put(mod); +} +EXPORT_SYMBOL(scsi_device_put); + +/* helper for shost_for_each_device, see that for documentation */ +struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, + struct scsi_device *prev) +{ + struct list_head *list = (prev ? &prev->siblings : &shost->__devices); + struct scsi_device *next = NULL; + unsigned long flags; + + spin_lock_irqsave(shost->host_lock, flags); + while (list->next != &shost->__devices) { + next = list_entry(list->next, struct scsi_device, siblings); + /* skip devices that we can't get a reference to */ + if (!scsi_device_get(next)) + break; + next = NULL; + list = list->next; + } + spin_unlock_irqrestore(shost->host_lock, flags); + + if (prev) + scsi_device_put(prev); + return next; +} +EXPORT_SYMBOL(__scsi_iterate_devices); + +/** + * starget_for_each_device - helper to walk all devices of a target + * @starget: target whose devices we want to iterate over. + * @data: Opaque passed to each function call. + * @fn: Function to call on each device + * + * This traverses over each device of @starget. The devices have + * a reference that must be released by scsi_host_put when breaking + * out of the loop. + */ +void starget_for_each_device(struct scsi_target *starget, void *data, + void (*fn)(struct scsi_device *, void *)) +{ + struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); + struct scsi_device *sdev; + + shost_for_each_device(sdev, shost) { + if ((sdev->channel == starget->channel) && + (sdev->id == starget->id)) + fn(sdev, data); + } +} +EXPORT_SYMBOL(starget_for_each_device); + +/** + * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) + * @starget: target whose devices we want to iterate over. + * @data: parameter for callback @fn() + * @fn: callback function that is invoked for each device + * + * This traverses over each device of @starget. It does _not_ + * take a reference on the scsi_device, so the whole loop must be + * protected by shost->host_lock. + * + * Note: The only reason why drivers would want to use this is because + * they need to access the device list in irq context. Otherwise you + * really want to use starget_for_each_device instead. + **/ +void __starget_for_each_device(struct scsi_target *starget, void *data, + void (*fn)(struct scsi_device *, void *)) +{ + struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); + struct scsi_device *sdev; + + __shost_for_each_device(sdev, shost) { + if ((sdev->channel == starget->channel) && + (sdev->id == starget->id)) + fn(sdev, data); + } +} +EXPORT_SYMBOL(__starget_for_each_device); + +/** + * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) + * @starget: SCSI target pointer + * @lun: SCSI Logical Unit Number + * + * Description: Looks up the scsi_device with the specified @lun for a given + * @starget. The returned scsi_device does not have an additional + * reference. You must hold the host's host_lock over this call and + * any access to the returned scsi_device. A scsi_device in state + * SDEV_DEL is skipped. + * + * Note: The only reason why drivers should use this is because + * they need to access the device list in irq context. Otherwise you + * really want to use scsi_device_lookup_by_target instead. + **/ +struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, + u64 lun) +{ + struct scsi_device *sdev; + + list_for_each_entry(sdev, &starget->devices, same_target_siblings) { + if (sdev->sdev_state == SDEV_DEL) + continue; + if (sdev->lun ==lun) + return sdev; + } + + return NULL; +} +EXPORT_SYMBOL(__scsi_device_lookup_by_target); + +/** + * scsi_device_lookup_by_target - find a device given the target + * @starget: SCSI target pointer + * @lun: SCSI Logical Unit Number + * + * Description: Looks up the scsi_device with the specified @lun for a given + * @starget. The returned scsi_device has an additional reference that + * needs to be released with scsi_device_put once you're done with it. + **/ +struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, + u64 lun) +{ + struct scsi_device *sdev; + struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); + unsigned long flags; + + spin_lock_irqsave(shost->host_lock, flags); + sdev = __scsi_device_lookup_by_target(starget, lun); + if (sdev && scsi_device_get(sdev)) + sdev = NULL; + spin_unlock_irqrestore(shost->host_lock, flags); + + return sdev; +} +EXPORT_SYMBOL(scsi_device_lookup_by_target); + +/** + * __scsi_device_lookup - find a device given the host (UNLOCKED) + * @shost: SCSI host pointer + * @channel: SCSI channel (zero if only one channel) + * @id: SCSI target number (physical unit number) + * @lun: SCSI Logical Unit Number + * + * Description: Looks up the scsi_device with the specified @channel, @id, @lun + * for a given host. The returned scsi_device does not have an additional + * reference. You must hold the host's host_lock over this call and any access + * to the returned scsi_device. + * + * Note: The only reason why drivers would want to use this is because + * they need to access the device list in irq context. Otherwise you + * really want to use scsi_device_lookup instead. + **/ +struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, + uint channel, uint id, u64 lun) +{ + struct scsi_device *sdev; + + list_for_each_entry(sdev, &shost->__devices, siblings) { + if (sdev->sdev_state == SDEV_DEL) + continue; + if (sdev->channel == channel && sdev->id == id && + sdev->lun ==lun) + return sdev; + } + + return NULL; +} +EXPORT_SYMBOL(__scsi_device_lookup); + +/** + * scsi_device_lookup - find a device given the host + * @shost: SCSI host pointer + * @channel: SCSI channel (zero if only one channel) + * @id: SCSI target number (physical unit number) + * @lun: SCSI Logical Unit Number + * + * Description: Looks up the scsi_device with the specified @channel, @id, @lun + * for a given host. The returned scsi_device has an additional reference that + * needs to be released with scsi_device_put once you're done with it. + **/ +struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, + uint channel, uint id, u64 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_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); |