|  | // 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 | 
|  | * | 
|  | *  <[email protected]> | 
|  | * | 
|  | *  Bug correction thanks go to : | 
|  | *      Rik Faith <[email protected]> | 
|  | *      Tommy Thorn <tthorn> | 
|  | *      Thomas Wuensche <[email protected]> | 
|  | * | 
|  | *  Modified by Eric Youngdale [email protected] or [email protected] to | 
|  | *  add scatter-gather, multiple outstanding request, and other | 
|  | *  enhancements. | 
|  | * | 
|  | *  Native multichannel, wide scsi, /proc/scsi and hot plugging | 
|  | *  support added by Michael Neuffer <[email protected]> | 
|  | * | 
|  | *  Added request_module("scsi_hostadapter") for kerneld: | 
|  | *  (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf) | 
|  | *  Bjorn Ekwall  <[email protected]> | 
|  | *  (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 <[email protected]> | 
|  | * | 
|  | *  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 <linux/async.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 | 
|  |  | 
|  | /* | 
|  | * Domain for asynchronous system resume operations.  It is marked 'exclusive' | 
|  | * to avoid being included in the async_synchronize_full() that is invoked by | 
|  | * dpm_resume(). | 
|  | */ | 
|  | ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain); | 
|  | EXPORT_SYMBOL(scsi_sd_pm_domain); | 
|  |  | 
|  | #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 (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", | 
|  | 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); | 
|  |  | 
|  | /* | 
|  | * If we have valid sense information, then some kind of recovery | 
|  | * must have taken place.  Make a note of this. | 
|  | */ | 
|  | if (SCSI_SENSE_VALID(cmd)) | 
|  | cmd->result |= (DRIVER_SENSE << 24); | 
|  |  | 
|  | SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, | 
|  | "Notifying upper driver of completion " | 
|  | "(result %x)\n", cmd->result)); | 
|  |  | 
|  | good_bytes = scsi_bufflen(cmd); | 
|  | if (!blk_rq_is_passthrough(cmd->request)) { | 
|  | 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); | 
|  | } | 
|  |  | 
|  | /** | 
|  | * 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) | 
|  | { | 
|  | if (depth > 0) { | 
|  | sdev->queue_depth = depth; | 
|  | wmb(); | 
|  | } | 
|  |  | 
|  | if (sdev->request_queue) | 
|  | blk_set_queue_depth(sdev->request_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 */ | 
|  | if (buffer[1] != page) | 
|  | return -EIO; | 
|  |  | 
|  | return get_unaligned_be16(&buffer[2]) + 4; | 
|  | } | 
|  |  | 
|  | /** | 
|  | * 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 returns a pointer | 
|  | * to a buffer containing the data from that page.  The caller is | 
|  | * responsible for calling kfree() on this pointer when it is no longer | 
|  | * needed.  If we cannot retrieve the VPD page this routine returns %NULL. | 
|  | */ | 
|  | int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, | 
|  | int buf_len) | 
|  | { | 
|  | int i, result; | 
|  |  | 
|  | if (sdev->skip_vpd_pages) | 
|  | goto fail; | 
|  |  | 
|  | /* Ask for all the pages supported by this device */ | 
|  | result = scsi_vpd_inquiry(sdev, buf, 0, buf_len); | 
|  | if (result < 4) | 
|  | goto fail; | 
|  |  | 
|  | /* If the user actually wanted this page, we can skip the rest */ | 
|  | if (page == 0) | 
|  | return 0; | 
|  |  | 
|  | for (i = 4; i < min(result, buf_len); i++) | 
|  | if (buf[i] == page) | 
|  | goto found; | 
|  |  | 
|  | if (i < result && i >= buf_len) | 
|  | /* ran off the end of the buffer, give us benefit of doubt */ | 
|  | goto found; | 
|  | /* The device claims it doesn't support the requested page */ | 
|  | goto fail; | 
|  |  | 
|  | found: | 
|  | result = scsi_vpd_inquiry(sdev, buf, page, buf_len); | 
|  | if (result < 0) | 
|  | goto fail; | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | fail: | 
|  | return -EINVAL; | 
|  | } | 
|  | 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 = SCSI_VPD_PG_LEN, result; | 
|  |  | 
|  | retry_pg: | 
|  | 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) { | 
|  | 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); | 
|  | } | 
|  | 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; | 
|  |  | 
|  | if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) | 
|  | 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(len, &cmd[6]); | 
|  | memset(buffer, 0, len); | 
|  |  | 
|  | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, | 
|  | &sshdr, 30 * HZ, 3, NULL); | 
|  |  | 
|  | 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); |