[mirror_ubuntu-artful-kernel.git] / block / blk-exec.c

/*
 * Functions related to setting various queue properties from drivers
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/sched/sysctl.h>

#include "blk.h"
#include "blk-mq-sched.h"

/**
 * blk_end_sync_rq - executes a completion event on a request
 * @rq: request to complete
 * @error: end I/O status of the request
 */
static void blk_end_sync_rq(struct request *rq, int error)
{
	struct completion *waiting = rq->end_io_data;

	rq->end_io_data = NULL;

	/*
	 * complete last, if this is a stack request the process (and thus
	 * the rq pointer) could be invalid right after this complete()
	 */
	complete(waiting);
}

/**
 * blk_execute_rq_nowait - insert a request into queue for execution
 * @q:		queue to insert the request in
 * @bd_disk:	matching gendisk
 * @rq:		request to insert
 * @at_head:    insert request at head or tail of queue
 * @done:	I/O completion handler
 *
 * Description:
 *    Insert a fully prepared request at the back of the I/O scheduler queue
 *    for execution.  Don't wait for completion.
 *
 * Note:
 *    This function will invoke @done directly if the queue is dead.
 */
void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
			   struct request *rq, int at_head,
			   rq_end_io_fn *done)
{
	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;

	WARN_ON(irqs_disabled());
	WARN_ON(!blk_rq_is_passthrough(rq));

	rq->rq_disk = bd_disk;
	rq->end_io = done;

	/*
	 * don't check dying flag for MQ because the request won't
	 * be reused after dying flag is set
	 */
	if (q->mq_ops) {
		blk_mq_sched_insert_request(rq, at_head, true, false, false);
		return;
	}

	spin_lock_irq(q->queue_lock);

	if (unlikely(blk_queue_dying(q))) {
		rq->rq_flags |= RQF_QUIET;
		rq->errors = -ENXIO;
		__blk_end_request_all(rq, rq->errors);
		spin_unlock_irq(q->queue_lock);
		return;
	}

	__elv_add_request(q, rq, where);
	__blk_run_queue(q);
	spin_unlock_irq(q->queue_lock);
}
EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);

/**
 * blk_execute_rq - insert a request into queue for execution
 * @q:		queue to insert the request in
 * @bd_disk:	matching gendisk
 * @rq:		request to insert
 * @at_head:    insert request at head or tail of queue
 *
 * Description:
 *    Insert a fully prepared request at the back of the I/O scheduler queue
 *    for execution and wait for completion.
 */
int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
		   struct request *rq, int at_head)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	int err = 0;
	unsigned long hang_check;

	rq->end_io_data = &wait;
	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);

	/* Prevent hang_check timer from firing at us during very long I/O */
	hang_check = sysctl_hung_task_timeout_secs;
	if (hang_check)
		while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
	else
		wait_for_completion_io(&wait);

	if (rq->errors)
		err = -EIO;

	return err;
}
EXPORT_SYMBOL(blk_execute_rq);
Commit	Line	Data
86db1e29 JA	1	/*
	2	* Functions related to setting various queue properties from drivers
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/bio.h>
	7	#include <linux/blkdev.h>
320ae51f	8	#include <linux/blk-mq.h>
cf4aebc2	9	#include <linux/sched/sysctl.h>
86db1e29 JA	10
86db1e29 JA	11	#include "blk.h"
bd166ef1	12	#include "blk-mq-sched.h"
86db1e29	13
86db1e29 JA	14	/**
	15	* blk_end_sync_rq - executes a completion event on a request
	16	* @rq: request to complete
710027a4	17	* @error: end I/O status of the request
86db1e29	18	*/
681a561b	19	static void blk_end_sync_rq(struct request *rq, int error)
86db1e29 JA	20	{
	21	struct completion *waiting = rq->end_io_data;
	22
	23	rq->end_io_data = NULL;
86db1e29 JA	24
	25	/*
	26	* complete last, if this is a stack request the process (and thus
	27	* the rq pointer) could be invalid right after this complete()
	28	*/
	29	complete(waiting);
	30	}
86db1e29 JA	31
	32	/**
	33	* blk_execute_rq_nowait - insert a request into queue for execution
	34	* @q: queue to insert the request in
	35	* @bd_disk: matching gendisk
	36	* @rq: request to insert
	37	* @at_head: insert request at head or tail of queue
	38	* @done: I/O completion handler
	39	*
	40	* Description:
710027a4	41	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29	42	* for execution. Don't wait for completion.
e81ca6fe MR	43	*
	44	* Note:
	45	* This function will invoke @done directly if the queue is dead.
86db1e29 JA	46	*/
	47	void blk_execute_rq_nowait(struct request_queue q, struct gendisk bd_disk,
	48	struct request *rq, int at_head,
	49	rq_end_io_fn *done)
	50	{
	51	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
	52
8ba61435	53	WARN_ON(irqs_disabled());
57292b58	54	WARN_ON(!blk_rq_is_passthrough(rq));
e81ca6fe MR	55
	56	rq->rq_disk = bd_disk;
	57	rq->end_io = done;
320ae51f	58
43a5e4e2 ML	59	/*
43a5e4e2 ML	60	* don't check dying flag for MQ because the request won't
68bdf1ac	61	* be reused after dying flag is set
43a5e4e2	62	*/
320ae51f	63	if (q->mq_ops) {
bd6737f1	64	blk_mq_sched_insert_request(rq, at_head, true, false, false);
320ae51f JA	65	return;
	66	}
	67
8ba61435 TH	68	spin_lock_irq(q->queue_lock);
8ba61435 TH	69
3f3299d5	70	if (unlikely(blk_queue_dying(q))) {
e8064021	71	rq->rq_flags \|= RQF_QUIET;
bfe159a5	72	rq->errors = -ENXIO;
7652113c	73	__blk_end_request_all(rq, rq->errors);
e81ca6fe	74	spin_unlock_irq(q->queue_lock);
bfe159a5 JB	75	return;
	76	}
	77
7eaceacc	78	__elv_add_request(q, rq, where);
24ecfbe2	79	__blk_run_queue(q);
86db1e29 JA	80	spin_unlock_irq(q->queue_lock);
	81	}
	82	EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
	83
	84	/**
	85	* blk_execute_rq - insert a request into queue for execution
	86	* @q: queue to insert the request in
	87	* @bd_disk: matching gendisk
	88	* @rq: request to insert
	89	* @at_head: insert request at head or tail of queue
	90	*
	91	* Description:
710027a4	92	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29 JA	93	* for execution and wait for completion.
	94	*/
	95	int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
	96	struct request *rq, int at_head)
	97	{
	98	DECLARE_COMPLETION_ONSTACK(wait);
86db1e29	99	int err = 0;
4b197769	100	unsigned long hang_check;
86db1e29	101
86db1e29 JA	102	rq->end_io_data = &wait;
86db1e29 JA	103	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
4b197769 ML	104
	105	/* Prevent hang_check timer from firing at us during very long I/O */
	106	hang_check = sysctl_hung_task_timeout_secs;
	107	if (hang_check)
5577022f	108	while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
4b197769	109	else
5577022f	110	wait_for_completion_io(&wait);
86db1e29 JA	111
	112	if (rq->errors)
	113	err = -EIO;
	114
	115	return err;
	116	}
86db1e29	117	EXPORT_SYMBOL(blk_execute_rq);