[linux.git] / block / blk-timeout.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"
#include "blk-mq.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 PTR_ERR_OR_ZERO(dir);
}

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);
		if (val)
			blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
		else
			blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
	}

	return count;
}

#endif /* CONFIG_FAIL_IO_TIMEOUT */

/**
 * 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);
	kblockd_schedule_work(&req->q->timeout_work);
}
EXPORT_SYMBOL_GPL(blk_abort_request);

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);
	}

}
Commit	Line	Data
242f9dcb JA	1	/*
	2	* Functions related to generic timeout handling of requests.
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/blkdev.h>
581d4e28	7	#include <linux/fault-inject.h>
242f9dcb JA	8
242f9dcb JA	9	#include "blk.h"
90415837	10	#include "blk-mq.h"
242f9dcb	11
581d4e28 JA	12	#ifdef CONFIG_FAIL_IO_TIMEOUT
	13
	14	static DECLARE_FAULT_ATTR(fail_io_timeout);
	15
	16	static int __init setup_fail_io_timeout(char *str)
	17	{
	18	return setup_fault_attr(&fail_io_timeout, str);
	19	}
	20	__setup("fail_io_timeout=", setup_fail_io_timeout);
	21
	22	int blk_should_fake_timeout(struct request_queue *q)
	23	{
	24	if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags))
	25	return 0;
	26
	27	return should_fail(&fail_io_timeout, 1);
	28	}
	29
	30	static int __init fail_io_timeout_debugfs(void)
	31	{
dd48c085 AM	32	struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout",
	33	NULL, &fail_io_timeout);
	34
8616ebb1	35	return PTR_ERR_OR_ZERO(dir);
581d4e28 JA	36	}
	37
	38	late_initcall(fail_io_timeout_debugfs);
	39
	40	ssize_t part_timeout_show(struct device dev, struct device_attribute attr,
	41	char *buf)
	42	{
	43	struct gendisk *disk = dev_to_disk(dev);
	44	int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags);
	45
	46	return sprintf(buf, "%d\n", set != 0);
	47	}
	48
	49	ssize_t part_timeout_store(struct device dev, struct device_attribute attr,
	50	const char *buf, size_t count)
	51	{
	52	struct gendisk *disk = dev_to_disk(dev);
	53	int val;
	54
	55	if (count) {
	56	struct request_queue *q = disk->queue;
	57	char p = (char ) buf;
	58
	59	val = simple_strtoul(p, &p, 10);
581d4e28	60	if (val)
8814ce8a	61	blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
581d4e28	62	else
8814ce8a	63	blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
581d4e28 JA	64	}
	65
	66	return count;
	67	}
	68
	69	#endif /* CONFIG_FAIL_IO_TIMEOUT */
	70
242f9dcb JA	71	/**
	72	* blk_abort_request -- Request request recovery for the specified command
	73	* @req: pointer to the request of interest
	74	*
	75	* This function requests that the block layer start recovery for the
	76	* request by deleting the timer and calling the q's timeout function.
	77	* LLDDs who implement their own error recovery MAY ignore the timeout
39795d65	78	* event if they generated blk_abort_request.
242f9dcb JA	79	*/
	80	void blk_abort_request(struct request *req)
	81	{
4316b79e JA	82	/*
	83	* All we need to ensure is that timeout scan takes place
	84	* immediately and that scan sees the new timeout value.
	85	* No need for fancy synchronizations.
	86	*/
079076b3	87	WRITE_ONCE(req->deadline, jiffies);
4316b79e	88	kblockd_schedule_work(&req->q->timeout_work);
242f9dcb JA	89	}
	90	EXPORT_SYMBOL_GPL(blk_abort_request);
	91
0d2602ca JA	92	unsigned long blk_rq_timeout(unsigned long timeout)
	93	{
	94	unsigned long maxt;
	95
	96	maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT);
	97	if (time_after(timeout, maxt))
	98	timeout = maxt;
	99
	100	return timeout;
	101	}
	102
c4a634f4 CH	103	/**
	104	* blk_add_timer - Start timeout timer for a single request
	105	* @req: request that is about to start running.
	106	*
	107	* Notes:
	108	* Each request has its own timer, and as it is added to the queue, we
	109	* set up the timer. When the request completes, we cancel the timer.
	110	*/
	111	void blk_add_timer(struct request *req)
242f9dcb JA	112	{
	113	struct request_queue *q = req->q;
	114	unsigned long expiry;
	115
2eef33e4 TH	116	/*
	117	* Some LLDs, like scsi, peek at the timeout to prevent a
	118	* command from being retried forever.
	119	*/
	120	if (!req->timeout)
242f9dcb	121	req->timeout = q->rq_timeout;
2eef33e4	122
f5e350f0	123	req->rq_flags &= ~RQF_TIMED_OUT;
079076b3 CH	124
	125	expiry = jiffies + req->timeout;
	126	WRITE_ONCE(req->deadline, expiry);
3b627a3f	127
242f9dcb JA	128	/*
242f9dcb JA	129	* If the timer isn't already pending or this timeout is earlier
7838c15b	130	* than an existing one, modify the timer. Round up to next nearest
242f9dcb JA	131	* second.
242f9dcb JA	132	*/
079076b3	133	expiry = blk_rq_timeout(round_jiffies_up(expiry));
242f9dcb JA	134
242f9dcb JA	135	if (!timer_pending(&q->timeout) \|\|
f793aa53 JA	136	time_before(expiry, q->timeout.expires)) {
	137	unsigned long diff = q->timeout.expires - expiry;
	138
	139	/*
	140	* Due to added timer slack to group timers, the timer
	141	* will often be a little in front of what we asked for.
	142	* So apply some tolerance here too, otherwise we keep
	143	* modifying the timer because expires for value X
	144	* will be X + something.
	145	*/
c7bca418	146	if (!timer_pending(&q->timeout) \|\| (diff >= HZ / 2))
f793aa53 JA	147	mod_timer(&q->timeout, expiry);
f793aa53 JA	148	}
320ae51f JA	149
320ae51f JA	150	}