[mirror_ubuntu-zesty-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 "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.
 */
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());
	spin_lock_irq(q->queue_lock);

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

	rq->rq_disk = bd_disk;
	rq->end_io = done;
	__elv_add_request(q, rq, where);
	__blk_run_queue(q);
	/* the queue is stopped so it won't be run */
	if (rq->cmd_type == REQ_TYPE_PM_RESUME)
		q->request_fn(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_timeout(&wait, hang_check * (HZ/2)));
	else
		wait_for_completion(&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>
	8
	9	#include "blk.h"
	10
	11	/*
	12	* for max sense size
	13	*/
	14	#include <scsi/scsi_cmnd.h>
	15
	16	/**
	17	* blk_end_sync_rq - executes a completion event on a request
	18	* @rq: request to complete
710027a4	19	* @error: end I/O status of the request
86db1e29	20	*/
681a561b	21	static void blk_end_sync_rq(struct request *rq, int error)
86db1e29 JA	22	{
	23	struct completion *waiting = rq->end_io_data;
	24
	25	rq->end_io_data = NULL;
	26	__blk_put_request(rq->q, rq);
	27
	28	/*
	29	* complete last, if this is a stack request the process (and thus
	30	* the rq pointer) could be invalid right after this complete()
	31	*/
	32	complete(waiting);
	33	}
86db1e29 JA	34
	35	/**
	36	* blk_execute_rq_nowait - insert a request into queue for execution
	37	* @q: queue to insert the request in
	38	* @bd_disk: matching gendisk
	39	* @rq: request to insert
	40	* @at_head: insert request at head or tail of queue
	41	* @done: I/O completion handler
	42	*
	43	* Description:
710027a4	44	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29 JA	45	* for execution. Don't wait for completion.
	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 TH	53	WARN_ON(irqs_disabled());
	54	spin_lock_irq(q->queue_lock);
	55
34f6055c	56	if (unlikely(blk_queue_dead(q))) {
8ba61435	57	spin_unlock_irq(q->queue_lock);
bfe159a5 JB	58	rq->errors = -ENXIO;
	59	if (rq->end_io)
	60	rq->end_io(rq, rq->errors);
	61	return;
	62	}
	63
86db1e29	64	rq->rq_disk = bd_disk;
86db1e29	65	rq->end_io = done;
7eaceacc	66	__elv_add_request(q, rq, where);
24ecfbe2	67	__blk_run_queue(q);
addd0a09	68	/* the queue is stopped so it won't be run */
33659ebb	69	if (rq->cmd_type == REQ_TYPE_PM_RESUME)
9a2d43b7	70	q->request_fn(q);
86db1e29 JA	71	spin_unlock_irq(q->queue_lock);
	72	}
	73	EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
	74
	75	/**
	76	* blk_execute_rq - insert a request into queue for execution
	77	* @q: queue to insert the request in
	78	* @bd_disk: matching gendisk
	79	* @rq: request to insert
	80	* @at_head: insert request at head or tail of queue
	81	*
	82	* Description:
710027a4	83	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29 JA	84	* for execution and wait for completion.
	85	*/
	86	int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
	87	struct request *rq, int at_head)
	88	{
	89	DECLARE_COMPLETION_ONSTACK(wait);
	90	char sense[SCSI_SENSE_BUFFERSIZE];
	91	int err = 0;
4b197769	92	unsigned long hang_check;
86db1e29 JA	93
	94	/*
	95	* we need an extra reference to the request, so we can look at
	96	* it after io completion
	97	*/
	98	rq->ref_count++;
	99
	100	if (!rq->sense) {
	101	memset(sense, 0, sizeof(sense));
	102	rq->sense = sense;
	103	rq->sense_len = 0;
	104	}
	105
	106	rq->end_io_data = &wait;
	107	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
4b197769 ML	108
	109	/* Prevent hang_check timer from firing at us during very long I/O */
	110	hang_check = sysctl_hung_task_timeout_secs;
	111	if (hang_check)
	112	while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
	113	else
	114	wait_for_completion(&wait);
86db1e29 JA	115
	116	if (rq->errors)
	117	err = -EIO;
	118
	119	return err;
	120	}
86db1e29	121	EXPORT_SYMBOL(blk_execute_rq);