[linux.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/sched/sysctl.h>

#include "blk.h"

/*
 * for max sense size
 */
#include <scsi/scsi_cmnd.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;
	__blk_put_request(rq->q, rq);

	/*
	 * 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;
	bool is_pm_resume;

	WARN_ON(irqs_disabled());

	rq->rq_disk = bd_disk;
	rq->end_io = done;
	/*
	 * need to check this before __blk_run_queue(), because rq can
	 * be freed before that returns.
	 */
	is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;

	spin_lock_irq(q->queue_lock);

	if (unlikely(blk_queue_dying(q))) {
		rq->errors = -ENXIO;
		if (rq->end_io)
			rq->end_io(rq, rq->errors);
		spin_unlock_irq(q->queue_lock);
		return;
	}

	__elv_add_request(q, rq, where);
	__blk_run_queue(q);
	/* the queue is stopped so it won't be run */
	if (is_pm_resume)
		__blk_run_queue_uncond(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);
	char sense[SCSI_SENSE_BUFFERSIZE];
	int err = 0;
	unsigned long hang_check;

	/*
	 * we need an extra reference to the request, so we can look at
	 * it after io completion
	 */
	rq->ref_count++;

	if (!rq->sense) {
		memset(sense, 0, sizeof(sense));
		rq->sense = sense;
		rq->sense_len = 0;
	}

	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>
cf4aebc2	8	#include <linux/sched/sysctl.h>
86db1e29 JA	9
	10	#include "blk.h"
	11
	12	/*
	13	* for max sense size
	14	*/
	15	#include <scsi/scsi_cmnd.h>
	16
	17	/**
	18	* blk_end_sync_rq - executes a completion event on a request
	19	* @rq: request to complete
710027a4	20	* @error: end I/O status of the request
86db1e29	21	*/
681a561b	22	static void blk_end_sync_rq(struct request *rq, int error)
86db1e29 JA	23	{
	24	struct completion *waiting = rq->end_io_data;
	25
	26	rq->end_io_data = NULL;
	27	__blk_put_request(rq->q, rq);
	28
	29	/*
	30	* complete last, if this is a stack request the process (and thus
	31	* the rq pointer) could be invalid right after this complete()
	32	*/
	33	complete(waiting);
	34	}
86db1e29 JA	35
	36	/**
	37	* blk_execute_rq_nowait - insert a request into queue for execution
	38	* @q: queue to insert the request in
	39	* @bd_disk: matching gendisk
	40	* @rq: request to insert
	41	* @at_head: insert request at head or tail of queue
	42	* @done: I/O completion handler
	43	*
	44	* Description:
710027a4	45	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29	46	* for execution. Don't wait for completion.
e81ca6fe MR	47	*
	48	* Note:
	49	* This function will invoke @done directly if the queue is dead.
86db1e29 JA	50	*/
	51	void blk_execute_rq_nowait(struct request_queue q, struct gendisk bd_disk,
	52	struct request *rq, int at_head,
	53	rq_end_io_fn *done)
	54	{
	55	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
893d290f	56	bool is_pm_resume;
86db1e29	57
8ba61435	58	WARN_ON(irqs_disabled());
e81ca6fe MR	59
	60	rq->rq_disk = bd_disk;
	61	rq->end_io = done;
893d290f RD	62	/*
	63	* need to check this before __blk_run_queue(), because rq can
	64	* be freed before that returns.
	65	*/
	66	is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
e81ca6fe	67
8ba61435 TH	68	spin_lock_irq(q->queue_lock);
8ba61435 TH	69
3f3299d5	70	if (unlikely(blk_queue_dying(q))) {
bfe159a5 JB	71	rq->errors = -ENXIO;
	72	if (rq->end_io)
	73	rq->end_io(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);
addd0a09	80	/* the queue is stopped so it won't be run */
893d290f	81	if (is_pm_resume)
c246e80d	82	__blk_run_queue_uncond(q);
86db1e29 JA	83	spin_unlock_irq(q->queue_lock);
	84	}
	85	EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
	86
	87	/**
	88	* blk_execute_rq - insert a request into queue for execution
	89	* @q: queue to insert the request in
	90	* @bd_disk: matching gendisk
	91	* @rq: request to insert
	92	* @at_head: insert request at head or tail of queue
	93	*
	94	* Description:
710027a4	95	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29 JA	96	* for execution and wait for completion.
	97	*/
	98	int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
	99	struct request *rq, int at_head)
	100	{
	101	DECLARE_COMPLETION_ONSTACK(wait);
	102	char sense[SCSI_SENSE_BUFFERSIZE];
	103	int err = 0;
4b197769	104	unsigned long hang_check;
86db1e29 JA	105
	106	/*
	107	* we need an extra reference to the request, so we can look at
	108	* it after io completion
	109	*/
	110	rq->ref_count++;
	111
	112	if (!rq->sense) {
	113	memset(sense, 0, sizeof(sense));
	114	rq->sense = sense;
	115	rq->sense_len = 0;
	116	}
	117
	118	rq->end_io_data = &wait;
	119	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
4b197769 ML	120
	121	/* Prevent hang_check timer from firing at us during very long I/O */
	122	hang_check = sysctl_hung_task_timeout_secs;
	123	if (hang_check)
5577022f	124	while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
4b197769	125	else
5577022f	126	wait_for_completion_io(&wait);
86db1e29 JA	127
	128	if (rq->errors)
	129	err = -EIO;
	130
	131	return err;
	132	}
86db1e29	133	EXPORT_SYMBOL(blk_execute_rq);