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linux-next/block/blk-timeout.c
Akinobu Mita dd48c085c1 fault-injection: add ability to export fault_attr in arbitrary directory
init_fault_attr_dentries() is used to export fault_attr via debugfs.
But it can only export it in debugfs root directory.

Per Forlin is working on mmc_fail_request which adds support to inject
data errors after a completed host transfer in MMC subsystem.

The fault_attr for mmc_fail_request should be defined per mmc host and
export it in debugfs directory per mmc host like
/sys/kernel/debug/mmc0/mmc_fail_request.

init_fault_attr_dentries() doesn't help for mmc_fail_request.  So this
introduces fault_create_debugfs_attr() which is able to create a
directory in the arbitrary directory and replace
init_fault_attr_dentries().

[akpm@linux-foundation.org: extraneous semicolon, per Randy]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Per Forlin <per.forlin@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-03 14:25:20 -10:00

241 lines
5.6 KiB
C

/*
* Functions related to generic timeout handling of requests.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/fault-inject.h>
#include "blk.h"
#ifdef CONFIG_FAIL_IO_TIMEOUT
static DECLARE_FAULT_ATTR(fail_io_timeout);
static int __init setup_fail_io_timeout(char *str)
{
return setup_fault_attr(&fail_io_timeout, str);
}
__setup("fail_io_timeout=", setup_fail_io_timeout);
int blk_should_fake_timeout(struct request_queue *q)
{
if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags))
return 0;
return should_fail(&fail_io_timeout, 1);
}
static int __init fail_io_timeout_debugfs(void)
{
struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout",
NULL, &fail_io_timeout);
return IS_ERR(dir) ? PTR_ERR(dir) : 0;
}
late_initcall(fail_io_timeout_debugfs);
ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags);
return sprintf(buf, "%d\n", set != 0);
}
ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct gendisk *disk = dev_to_disk(dev);
int val;
if (count) {
struct request_queue *q = disk->queue;
char *p = (char *) buf;
val = simple_strtoul(p, &p, 10);
spin_lock_irq(q->queue_lock);
if (val)
queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
else
queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
spin_unlock_irq(q->queue_lock);
}
return count;
}
#endif /* CONFIG_FAIL_IO_TIMEOUT */
/*
* blk_delete_timer - Delete/cancel timer for a given function.
* @req: request that we are canceling timer for
*
*/
void blk_delete_timer(struct request *req)
{
list_del_init(&req->timeout_list);
}
static void blk_rq_timed_out(struct request *req)
{
struct request_queue *q = req->q;
enum blk_eh_timer_return ret;
ret = q->rq_timed_out_fn(req);
switch (ret) {
case BLK_EH_HANDLED:
__blk_complete_request(req);
break;
case BLK_EH_RESET_TIMER:
blk_clear_rq_complete(req);
blk_add_timer(req);
break;
case BLK_EH_NOT_HANDLED:
/*
* LLD handles this for now but in the future
* we can send a request msg to abort the command
* and we can move more of the generic scsi eh code to
* the blk layer.
*/
break;
default:
printk(KERN_ERR "block: bad eh return: %d\n", ret);
break;
}
}
void blk_rq_timed_out_timer(unsigned long data)
{
struct request_queue *q = (struct request_queue *) data;
unsigned long flags, next = 0;
struct request *rq, *tmp;
int next_set = 0;
spin_lock_irqsave(q->queue_lock, flags);
list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
if (time_after_eq(jiffies, rq->deadline)) {
list_del_init(&rq->timeout_list);
/*
* Check if we raced with end io completion
*/
if (blk_mark_rq_complete(rq))
continue;
blk_rq_timed_out(rq);
} else if (!next_set || time_after(next, rq->deadline)) {
next = rq->deadline;
next_set = 1;
}
}
if (next_set)
mod_timer(&q->timeout, round_jiffies_up(next));
spin_unlock_irqrestore(q->queue_lock, flags);
}
/**
* blk_abort_request -- Request request recovery for the specified command
* @req: pointer to the request of interest
*
* This function requests that the block layer start recovery for the
* request by deleting the timer and calling the q's timeout function.
* LLDDs who implement their own error recovery MAY ignore the timeout
* event if they generated blk_abort_req. Must hold queue lock.
*/
void blk_abort_request(struct request *req)
{
if (blk_mark_rq_complete(req))
return;
blk_delete_timer(req);
blk_rq_timed_out(req);
}
EXPORT_SYMBOL_GPL(blk_abort_request);
/**
* blk_add_timer - Start timeout timer for a single request
* @req: request that is about to start running.
*
* Notes:
* Each request has its own timer, and as it is added to the queue, we
* set up the timer. When the request completes, we cancel the timer.
*/
void blk_add_timer(struct request *req)
{
struct request_queue *q = req->q;
unsigned long expiry;
if (!q->rq_timed_out_fn)
return;
BUG_ON(!list_empty(&req->timeout_list));
BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
/*
* Some LLDs, like scsi, peek at the timeout to prevent a
* command from being retried forever.
*/
if (!req->timeout)
req->timeout = q->rq_timeout;
req->deadline = jiffies + req->timeout;
list_add_tail(&req->timeout_list, &q->timeout_list);
/*
* If the timer isn't already pending or this timeout is earlier
* than an existing one, modify the timer. Round up to next nearest
* second.
*/
expiry = round_jiffies_up(req->deadline);
if (!timer_pending(&q->timeout) ||
time_before(expiry, q->timeout.expires))
mod_timer(&q->timeout, expiry);
}
/**
* blk_abort_queue -- Abort all request on given queue
* @queue: pointer to queue
*
*/
void blk_abort_queue(struct request_queue *q)
{
unsigned long flags;
struct request *rq, *tmp;
LIST_HEAD(list);
/*
* Not a request based block device, nothing to abort
*/
if (!q->request_fn)
return;
spin_lock_irqsave(q->queue_lock, flags);
elv_abort_queue(q);
/*
* Splice entries to local list, to avoid deadlocking if entries
* get readded to the timeout list by error handling
*/
list_splice_init(&q->timeout_list, &list);
list_for_each_entry_safe(rq, tmp, &list, timeout_list)
blk_abort_request(rq);
/*
* Occasionally, blk_abort_request() will return without
* deleting the element from the list. Make sure we add those back
* instead of leaving them on the local stack list.
*/
list_splice(&list, &q->timeout_list);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL_GPL(blk_abort_queue);