blob: 8aa68fae96ad8d87b41890cc8a77654a60feecbc [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
* 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"
#include "blk-mq.h"
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 PTR_ERR_OR_ZERO(dir);
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);
if (val)
blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
return count;
* 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_request.
void blk_abort_request(struct request *req)
* All we need to ensure is that timeout scan takes place
* immediately and that scan sees the new timeout value.
* No need for fancy synchronizations.
WRITE_ONCE(req->deadline, jiffies);
unsigned long blk_rq_timeout(unsigned long timeout)
unsigned long maxt;
maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT);
if (time_after(timeout, maxt))
timeout = maxt;
return timeout;
* 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;
* 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->rq_flags &= ~RQF_TIMED_OUT;
expiry = jiffies + req->timeout;
WRITE_ONCE(req->deadline, expiry);
* 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 = blk_rq_timeout(round_jiffies_up(expiry));
if (!timer_pending(&q->timeout) ||
time_before(expiry, q->timeout.expires)) {
unsigned long diff = q->timeout.expires - expiry;
* Due to added timer slack to group timers, the timer
* will often be a little in front of what we asked for.
* So apply some tolerance here too, otherwise we keep
* modifying the timer because expires for value X
* will be X + something.
if (!timer_pending(&q->timeout) || (diff >= HZ / 2))
mod_timer(&q->timeout, expiry);