linux/drivers/scsi/scsi.c
Christoph Hellwig cff549e486 scsi: proper state checking and module refcount handling in scsi_device_get
This effectively reverts commits 85b6c7 ("[SCSI] sd: fix cache flushing on
module removal (and individual device removal)" and dc4515ea ("scsi: always
increment reference count").

We now never call scsi_device_get from the shutdown path, and the fact
that we started grabbing reference there in commit 85b6c7 turned out
turned out to create more problems than it solves, and required
workarounds for workarounds for workarounds. Move back to properly checking
the device state and carefully handle module refcounting.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2015-03-19 06:43:15 -07:00

1273 lines
34 KiB
C

/*
* 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 <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
/* sd, scsi core and power management need to coordinate flushing async actions */
ASYNC_DOMAIN(scsi_sd_probe_domain);
EXPORT_SYMBOL(scsi_sd_probe_domain);
/*
* Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
* 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);
/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
* You may not alter any existing entry (although adding new ones is
* encouraged once assigned by ANSI/INCITS T10
*/
static const char *const scsi_device_types[] = {
"Direct-Access ",
"Sequential-Access",
"Printer ",
"Processor ",
"WORM ",
"CD-ROM ",
"Scanner ",
"Optical Device ",
"Medium Changer ",
"Communications ",
"ASC IT8 ",
"ASC IT8 ",
"RAID ",
"Enclosure ",
"Direct-Access-RBC",
"Optical card ",
"Bridge controller",
"Object storage ",
"Automation/Drive ",
"Security Manager ",
"Direct-Access-ZBC",
};
/**
* scsi_device_type - Return 17 char string indicating device type.
* @type: type number to look up
*/
const char * scsi_device_type(unsigned type)
{
if (type == 0x1e)
return "Well-known LUN ";
if (type == 0x1f)
return "No Device ";
if (type >= ARRAY_SIZE(scsi_device_types))
return "Unknown ";
return scsi_device_types[type];
}
EXPORT_SYMBOL(scsi_device_type);
struct scsi_host_cmd_pool {
struct kmem_cache *cmd_slab;
struct kmem_cache *sense_slab;
unsigned int users;
char *cmd_name;
char *sense_name;
unsigned int slab_flags;
gfp_t gfp_mask;
};
static struct scsi_host_cmd_pool scsi_cmd_pool = {
.cmd_name = "scsi_cmd_cache",
.sense_name = "scsi_sense_cache",
.slab_flags = SLAB_HWCACHE_ALIGN,
};
static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
.cmd_name = "scsi_cmd_cache(DMA)",
.sense_name = "scsi_sense_cache(DMA)",
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
.gfp_mask = __GFP_DMA,
};
static DEFINE_MUTEX(host_cmd_pool_mutex);
/**
* scsi_host_free_command - internal function to release a command
* @shost: host to free the command for
* @cmd: command to release
*
* the command must previously have been allocated by
* scsi_host_alloc_command.
*/
static void
scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
struct scsi_host_cmd_pool *pool = shost->cmd_pool;
if (cmd->prot_sdb)
kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
kmem_cache_free(pool->cmd_slab, cmd);
}
/**
* scsi_host_alloc_command - internal function to allocate command
* @shost: SCSI host whose pool to allocate from
* @gfp_mask: mask for the allocation
*
* Returns a fully allocated command with sense buffer and protection
* data buffer (where applicable) or NULL on failure
*/
static struct scsi_cmnd *
scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
{
struct scsi_host_cmd_pool *pool = shost->cmd_pool;
struct scsi_cmnd *cmd;
cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
if (!cmd)
goto fail;
cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
gfp_mask | pool->gfp_mask);
if (!cmd->sense_buffer)
goto fail_free_cmd;
if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
if (!cmd->prot_sdb)
goto fail_free_sense;
}
return cmd;
fail_free_sense:
kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
fail_free_cmd:
kmem_cache_free(pool->cmd_slab, cmd);
fail:
return NULL;
}
/**
* __scsi_get_command - Allocate a struct scsi_cmnd
* @shost: host to transmit command
* @gfp_mask: allocation mask
*
* Description: allocate a struct scsi_cmd from host's slab, recycling from the
* host's free_list if necessary.
*/
static struct scsi_cmnd *
__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
{
struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, 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);
if (cmd) {
void *buf, *prot;
buf = cmd->sense_buffer;
prot = cmd->prot_sdb;
memset(cmd, 0, sizeof(*cmd));
cmd->sense_buffer = buf;
cmd->prot_sdb = prot;
}
}
return cmd;
}
/**
* scsi_get_command - Allocate and setup a scsi command block
* @dev: parent scsi device
* @gfp_mask: allocator flags
*
* Returns: The allocated scsi command structure.
*/
struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
{
struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
unsigned long flags;
if (unlikely(cmd == NULL))
return NULL;
cmd->device = dev;
INIT_LIST_HEAD(&cmd->list);
INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
spin_lock_irqsave(&dev->list_lock, flags);
list_add_tail(&cmd->list, &dev->cmd_list);
spin_unlock_irqrestore(&dev->list_lock, flags);
cmd->jiffies_at_alloc = jiffies;
return cmd;
}
/**
* __scsi_put_command - Free a struct scsi_cmnd
* @shost: dev->host
* @cmd: Command to free
*/
static void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
unsigned long flags;
if (unlikely(list_empty(&shost->free_list))) {
spin_lock_irqsave(&shost->free_list_lock, flags);
if (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))
scsi_host_free_command(shost, cmd);
}
/**
* scsi_put_command - Free a scsi command block
* @cmd: command block to free
*
* Returns: Nothing.
*
* Notes: The command must not belong to any lists.
*/
void scsi_put_command(struct scsi_cmnd *cmd)
{
unsigned long flags;
/* serious error if the command hasn't come from a device list */
spin_lock_irqsave(&cmd->device->list_lock, flags);
BUG_ON(list_empty(&cmd->list));
list_del_init(&cmd->list);
spin_unlock_irqrestore(&cmd->device->list_lock, flags);
BUG_ON(delayed_work_pending(&cmd->abort_work));
__scsi_put_command(cmd->device->host, cmd);
}
static struct scsi_host_cmd_pool *
scsi_find_host_cmd_pool(struct Scsi_Host *shost)
{
if (shost->hostt->cmd_size)
return shost->hostt->cmd_pool;
if (shost->unchecked_isa_dma)
return &scsi_cmd_dma_pool;
return &scsi_cmd_pool;
}
static void
scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
{
kfree(pool->sense_name);
kfree(pool->cmd_name);
kfree(pool);
}
static struct scsi_host_cmd_pool *
scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
{
struct scsi_host_template *hostt = shost->hostt;
struct scsi_host_cmd_pool *pool;
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
if (!pool)
return NULL;
pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->proc_name);
pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->proc_name);
if (!pool->cmd_name || !pool->sense_name) {
scsi_free_host_cmd_pool(pool);
return NULL;
}
pool->slab_flags = SLAB_HWCACHE_ALIGN;
if (shost->unchecked_isa_dma) {
pool->slab_flags |= SLAB_CACHE_DMA;
pool->gfp_mask = __GFP_DMA;
}
if (hostt->cmd_size)
hostt->cmd_pool = pool;
return pool;
}
static struct scsi_host_cmd_pool *
scsi_get_host_cmd_pool(struct Scsi_Host *shost)
{
struct scsi_host_template *hostt = shost->hostt;
struct scsi_host_cmd_pool *retval = NULL, *pool;
size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
/*
* Select a command slab for this host and create it if not
* yet existent.
*/
mutex_lock(&host_cmd_pool_mutex);
pool = scsi_find_host_cmd_pool(shost);
if (!pool) {
pool = scsi_alloc_host_cmd_pool(shost);
if (!pool)
goto out;
}
if (!pool->users) {
pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
pool->slab_flags, NULL);
if (!pool->cmd_slab)
goto out_free_pool;
pool->sense_slab = kmem_cache_create(pool->sense_name,
SCSI_SENSE_BUFFERSIZE, 0,
pool->slab_flags, NULL);
if (!pool->sense_slab)
goto out_free_slab;
}
pool->users++;
retval = pool;
out:
mutex_unlock(&host_cmd_pool_mutex);
return retval;
out_free_slab:
kmem_cache_destroy(pool->cmd_slab);
out_free_pool:
if (hostt->cmd_size) {
scsi_free_host_cmd_pool(pool);
hostt->cmd_pool = NULL;
}
goto out;
}
static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
{
struct scsi_host_template *hostt = shost->hostt;
struct scsi_host_cmd_pool *pool;
mutex_lock(&host_cmd_pool_mutex);
pool = scsi_find_host_cmd_pool(shost);
/*
* This may happen if a driver has a mismatched get and put
* of the command pool; the driver should be implicated in
* the stack trace
*/
BUG_ON(pool->users == 0);
if (!--pool->users) {
kmem_cache_destroy(pool->cmd_slab);
kmem_cache_destroy(pool->sense_slab);
if (hostt->cmd_size) {
scsi_free_host_cmd_pool(pool);
hostt->cmd_pool = NULL;
}
}
mutex_unlock(&host_cmd_pool_mutex);
}
/**
* scsi_setup_command_freelist - Setup the command freelist for a scsi host.
* @shost: host to allocate the freelist for.
*
* Description: The command freelist protects against system-wide out of memory
* deadlock by preallocating one SCSI command structure for each host, so the
* system can always write to a swap file on a device associated with that host.
*
* Returns: Nothing.
*/
int scsi_setup_command_freelist(struct Scsi_Host *shost)
{
const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
struct scsi_cmnd *cmd;
spin_lock_init(&shost->free_list_lock);
INIT_LIST_HEAD(&shost->free_list);
shost->cmd_pool = scsi_get_host_cmd_pool(shost);
if (!shost->cmd_pool)
return -ENOMEM;
/*
* Get one backup command for this host.
*/
cmd = scsi_host_alloc_command(shost, gfp_mask);
if (!cmd) {
scsi_put_host_cmd_pool(shost);
shost->cmd_pool = NULL;
return -ENOMEM;
}
list_add(&cmd->list, &shost->free_list);
return 0;
}
/**
* scsi_destroy_command_freelist - Release the command freelist for a scsi host.
* @shost: host whose freelist is going to be destroyed
*/
void scsi_destroy_command_freelist(struct Scsi_Host *shost)
{
/*
* If cmd_pool is NULL the free list was not initialized, so
* do not attempt to release resources.
*/
if (!shost->cmd_pool)
return;
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);
scsi_host_free_command(shost, cmd);
}
shost->cmd_pool = NULL;
scsi_put_host_cmd_pool(shost);
}
#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",
atomic_read(&cmd->device->host->host_busy),
cmd->device->host->host_failed);
}
}
}
#endif
/**
* scsi_cmd_get_serial - Assign a serial number to a command
* @host: the scsi host
* @cmd: command to assign serial number to
*
* Description: a serial number identifies a request for error recovery
* and debugging purposes. Protected by the Host_Lock of host.
*/
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++;
}
EXPORT_SYMBOL(scsi_cmd_get_serial);
/**
* 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);
/*
* 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 (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
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)
{
unsigned long flags;
if (depth <= 0)
goto out;
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.
*
* Do not resize the tag map if it is a host wide share bqt,
* because the size should be the hosts's can_queue. If there
* is more IO than the LLD's can_queue (so there are not enuogh
* tags) request_fn's host queue ready check will handle it.
*/
if (!shost_use_blk_mq(sdev->host) && !sdev->host->bqt) {
if (blk_queue_tagged(sdev->request_queue) &&
blk_queue_resize_tags(sdev->request_queue, depth) != 0)
goto out_unlock;
}
sdev->queue_depth = depth;
out_unlock:
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
out:
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_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 result, i;
int vpd_len = SCSI_VPD_PG_LEN;
int pg80_supported = 0;
int pg83_supported = 0;
unsigned char *vpd_buf;
if (sdev->skip_vpd_pages)
return;
retry_pg0:
vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
if (!vpd_buf)
return;
/* Ask for all the pages supported by this device */
result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
if (result < 0) {
kfree(vpd_buf);
return;
}
if (result > vpd_len) {
vpd_len = result;
kfree(vpd_buf);
goto retry_pg0;
}
for (i = 4; i < result; i++) {
if (vpd_buf[i] == 0x80)
pg80_supported = 1;
if (vpd_buf[i] == 0x83)
pg83_supported = 1;
}
kfree(vpd_buf);
vpd_len = SCSI_VPD_PG_LEN;
if (pg80_supported) {
retry_pg80:
vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
if (!vpd_buf)
return;
result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
if (result < 0) {
kfree(vpd_buf);
return;
}
if (result > vpd_len) {
vpd_len = result;
kfree(vpd_buf);
goto retry_pg80;
}
sdev->vpd_pg80_len = result;
sdev->vpd_pg80 = vpd_buf;
vpd_len = SCSI_VPD_PG_LEN;
}
if (pg83_supported) {
retry_pg83:
vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
if (!vpd_buf)
return;
result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
if (result < 0) {
kfree(vpd_buf);
return;
}
if (result > vpd_len) {
vpd_len = result;
kfree(vpd_buf);
goto retry_pg83;
}
sdev->vpd_pg83_len = result;
sdev->vpd_pg83 = 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)
{
module_put(sdev->host->hostt->module);
put_device(&sdev->sdev_gendev);
}
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->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");
#ifdef CONFIG_SCSI_MQ_DEFAULT
bool scsi_use_blk_mq = true;
#else
bool scsi_use_blk_mq = false;
#endif
module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
static int __init init_scsi(void)
{
int error;
error = scsi_init_queue();
if (error)
return error;
error = scsi_init_procfs();
if (error)
goto cleanup_queue;
error = scsi_init_devinfo();
if (error)
goto cleanup_procfs;
error = scsi_init_hosts();
if (error)
goto cleanup_devlist;
error = scsi_init_sysctl();
if (error)
goto cleanup_hosts;
error = scsi_sysfs_register();
if (error)
goto cleanup_sysctl;
scsi_netlink_init();
printk(KERN_NOTICE "SCSI subsystem initialized\n");
return 0;
cleanup_sysctl:
scsi_exit_sysctl();
cleanup_hosts:
scsi_exit_hosts();
cleanup_devlist:
scsi_exit_devinfo();
cleanup_procfs:
scsi_exit_procfs();
cleanup_queue:
scsi_exit_queue();
printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
-error);
return error;
}
static void __exit exit_scsi(void)
{
scsi_netlink_exit();
scsi_sysfs_unregister();
scsi_exit_sysctl();
scsi_exit_hosts();
scsi_exit_devinfo();
scsi_exit_procfs();
scsi_exit_queue();
async_unregister_domain(&scsi_sd_probe_domain);
}
subsys_initcall(init_scsi);
module_exit(exit_scsi);