[net-next-2.6.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;

	rq->rq_disk = bd_disk;
	rq->end_io = done;
	WARN_ON(irqs_disabled());
	spin_lock_irq(q->queue_lock);
	__elv_add_request(q, rq, where, 1);
	__generic_unplug_device(q);
	/* the queue is stopped so it won't be plugged+unplugged */
	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
	53	rq->rq_disk = bd_disk;
86db1e29 JA	54	rq->end_io = done;
	55	WARN_ON(irqs_disabled());
	56	spin_lock_irq(q->queue_lock);
	57	__elv_add_request(q, rq, where, 1);
	58	__generic_unplug_device(q);
9a2d43b7	59	/* the queue is stopped so it won't be plugged+unplugged */
33659ebb	60	if (rq->cmd_type == REQ_TYPE_PM_RESUME)
9a2d43b7	61	q->request_fn(q);
86db1e29 JA	62	spin_unlock_irq(q->queue_lock);
	63	}
	64	EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
	65
	66	/**
	67	* blk_execute_rq - insert a request into queue for execution
	68	* @q: queue to insert the request in
	69	* @bd_disk: matching gendisk
	70	* @rq: request to insert
	71	* @at_head: insert request at head or tail of queue
	72	*
	73	* Description:
710027a4	74	* Insert a fully prepared request at the back of the I/O scheduler queue
86db1e29 JA	75	* for execution and wait for completion.
	76	*/
	77	int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
	78	struct request *rq, int at_head)
	79	{
	80	DECLARE_COMPLETION_ONSTACK(wait);
	81	char sense[SCSI_SENSE_BUFFERSIZE];
	82	int err = 0;
4b197769	83	unsigned long hang_check;
86db1e29 JA	84
	85	/*
	86	* we need an extra reference to the request, so we can look at
	87	* it after io completion
	88	*/
	89	rq->ref_count++;
	90
	91	if (!rq->sense) {
	92	memset(sense, 0, sizeof(sense));
	93	rq->sense = sense;
	94	rq->sense_len = 0;
	95	}
	96
	97	rq->end_io_data = &wait;
	98	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
4b197769 ML	99
	100	/* Prevent hang_check timer from firing at us during very long I/O */
	101	hang_check = sysctl_hung_task_timeout_secs;
	102	if (hang_check)
	103	while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
	104	else
	105	wait_for_completion(&wait);
86db1e29 JA	106
	107	if (rq->errors)
	108	err = -EIO;
	109
	110	return err;
	111	}
86db1e29	112	EXPORT_SYMBOL(blk_execute_rq);