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kernel-aes67/drivers/scsi/scsi.c

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// 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_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
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;
}
enum scsi_vpd_parameters {
SCSI_VPD_HEADER_SIZE = 4,
SCSI_VPD_LIST_SIZE = 36,
};
static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
{
unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
int result;
if (sdev->no_vpd_size)
return SCSI_DEFAULT_VPD_LEN;
/*
* Fetch the supported pages VPD and validate that the requested page
* number is present.
*/
if (page != 0) {
result = scsi_vpd_inquiry(sdev, vpd, 0, sizeof(vpd));
if (result < SCSI_VPD_HEADER_SIZE)
return 0;
result -= SCSI_VPD_HEADER_SIZE;
if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
return 0;
}
/*
* 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, page, SCSI_VPD_HEADER_SIZE);
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);
if (vpd_buf->data[i] == 0xb7)
scsi_update_vpd_page(sdev, 0xb7, &sdev->vpd_pgb7);
}
kfree(vpd_buf);
}
/**
* scsi_report_opcode - Find out if a given command is supported
* @sdev: scsi device to query
* @buffer: scratch buffer (must be at least 20 bytes long)
* @len: length of buffer
* @opcode: opcode for the command to look up
* @sa: service action for the command to look up
*
* Uses the REPORT SUPPORTED OPERATION CODES to check support for the
* command identified with @opcode and @sa. If the command does not
* have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
* 0 if the command is not supported 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 short sa)
{
unsigned char cmd[16];
struct scsi_sense_hdr sshdr;
int result, request_len;
const struct scsi_exec_args exec_args = {
.sshdr = &sshdr,
};
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;
if (!sa) {
cmd[2] = 1; /* One command format */
cmd[3] = opcode;
} else {
cmd[2] = 3; /* One command format with service action */
cmd[3] = opcode;
put_unaligned_be16(sa, &cmd[4]);
}
put_unaligned_be32(request_len, &cmd[6]);
memset(buffer, 0, len);
result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer,
request_len, 30 * HZ, 3, &exec_args);
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);
#define SCSI_CDL_CHECK_BUF_LEN 64
static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
unsigned char *buf)
{
int ret;
u8 cdlp;
/* Check operation code */
ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
if (ret <= 0)
return false;
if ((buf[1] & 0x03) != 0x03)
return false;
/*
* See SPC-6, One_command parameter data format for
* REPORT SUPPORTED OPERATION CODES. We have the following cases
* depending on rwcdlp (buf[0] & 0x01) value:
* - rwcdlp == 0: then cdlp indicates support for the A mode page when
* it is equal to 1 and for the B mode page when it is
* equal to 2.
* - rwcdlp == 1: then cdlp indicates support for the T2A mode page
* when it is equal to 1 and for the T2B mode page when
* it is equal to 2.
* Overall, to detect support for command duration limits, we only need
* to check that cdlp is 1 or 2.
*/
cdlp = (buf[1] & 0x18) >> 3;
return cdlp == 0x01 || cdlp == 0x02;
}
/**
* scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
* @sdev: The device to check
*/
void scsi_cdl_check(struct scsi_device *sdev)
{
bool cdl_supported;
unsigned char *buf;
/*
* Support for CDL was defined in SPC-5. Ignore devices reporting an
* lower SPC version. This also avoids problems with old drives choking
* on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
* service action specified, as done in scsi_cdl_check_cmd().
*/
if (sdev->scsi_level < SCSI_SPC_5) {
sdev->cdl_supported = 0;
return;
}
buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
if (!buf) {
sdev->cdl_supported = 0;
return;
}
/* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
cdl_supported =
scsi_cdl_check_cmd(sdev, READ_16, 0, buf) ||
scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) ||
scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
if (cdl_supported) {
/*
* We have CDL support: force the use of READ16/WRITE16.
* READ32 and WRITE32 will be used for devices that support
* the T10_PI_TYPE2_PROTECTION protection type.
*/
sdev->use_16_for_rw = 1;
sdev->use_10_for_rw = 0;
sdev->cdl_supported = 1;
} else {
sdev->cdl_supported = 0;
}
kfree(buf);
}
/**
* scsi_cdl_enable - Enable or disable a SCSI device supports for Command
* Duration Limits
* @sdev: The target device
* @enable: the target state
*/
int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
{
struct scsi_mode_data data;
struct scsi_sense_hdr sshdr;
struct scsi_vpd *vpd;
bool is_ata = false;
char buf[64];
int ret;
if (!sdev->cdl_supported)
return -EOPNOTSUPP;
rcu_read_lock();
vpd = rcu_dereference(sdev->vpd_pg89);
if (vpd)
is_ata = true;
rcu_read_unlock();
/*
* For ATA devices, CDL needs to be enabled with a SET FEATURES command.
*/
if (is_ata) {
char *buf_data;
int len;
ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
5 * HZ, 3, &data, NULL);
if (ret)
return -EINVAL;
/* Enable CDL using the ATA feature page */
len = min_t(size_t, sizeof(buf),
data.length - data.header_length -
data.block_descriptor_length);
buf_data = buf + data.header_length +
data.block_descriptor_length;
if (enable)
buf_data[4] = 0x02;
else
buf_data[4] = 0;
ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
&data, &sshdr);
if (ret) {
if (ret > 0 && scsi_sense_valid(&sshdr))
scsi_print_sense_hdr(sdev,
dev_name(&sdev->sdev_gendev), &sshdr);
return ret;
}
}
sdev->cdl_enable = enable;
return 0;
}
/**
* 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 (!try_module_get(sdev->host->hostt->module))
goto fail;
if (!get_device(&sdev->sdev_gendev))
goto fail_put_module;
return 0;
fail_put_module:
module_put(sdev->host->hostt->module);
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);
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