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Commit e3a04fe3 authored by Kiyoshi Ueda's avatar Kiyoshi Ueda Committed by Jens Axboe
Browse files

blk_end_request: add bidi completion interface (take 4) 



This patch adds a variant of the interface, blk_end_bidi_request(),
which completes a bidi request.

Bidi request must be completed as a whole, both rq and rq->next_rq
at once.  So the interface has 2 arguments for completion size.

As for ->end_io, only rq->end_io is called (rq->next_rq->end_io is not
called).  So if special completion handling is needed, the handler
must be set to rq->end_io.
And the handler must take care of freeing next_rq too, since
the interface doesn't care of it if rq->end_io is not NULL.

Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent aaa04c28

block/ll_rw_blk.c

+35 −5
Original line number Diff line number Diff line
@@ -3821,6 +3821,9 @@ static void complete_request(struct request *rq, int error) 
	if (blk_queued_rq(rq))

		blkdev_dequeue_request(rq);



	if (blk_bidi_rq(rq) && !rq->end_io)

		__blk_put_request(rq->next_rq->q, rq->next_rq);



	end_that_request_last(rq, uptodate);

}
@@ -3828,14 +3831,15 @@ static void complete_request(struct request *rq, int error) 
 * blk_end_io - Generic end_io function to complete a request.

 * @rq:           the request being processed

 * @error:        0 for success, < 0 for error

 * @nr_bytes:     number of bytes to complete

 * @nr_bytes:     number of bytes to complete @rq

 * @bidi_bytes:   number of bytes to complete @rq->next_rq

 * @drv_callback: function called between completion of bios in the request

 *                and completion of the request.

 *                If the callback returns non 0, this helper returns without

 *                completion of the request.

 *

 * Description:

 *     Ends I/O on a number of bytes attached to @rq.

 *     Ends I/O on a number of bytes attached to @rq and @rq->next_rq.

 *     If @rq has leftover, sets it up for the next range of segments.

 *

 * Return:
@@ -3843,7 +3847,7 @@ static void complete_request(struct request *rq, int error) 
 *     1 - this request is not freed yet, it still has pending buffers.

 **/

static int blk_end_io(struct request *rq, int error, int nr_bytes,

		      int (drv_callback)(struct request *))

		      int bidi_bytes, int (drv_callback)(struct request *))

{

	struct request_queue *q = rq->q;

	unsigned long flags = 0UL;
@@ -3858,6 +3862,11 @@ static int blk_end_io(struct request *rq, int error, int nr_bytes, 
	if (blk_fs_request(rq) || blk_pc_request(rq)) {

		if (__end_that_request_first(rq, uptodate, nr_bytes))

			return 1;



		/* Bidi request must be completed as a whole */

		if (blk_bidi_rq(rq) &&

		    __end_that_request_first(rq->next_rq, uptodate, bidi_bytes))

			return 1;

	}



	/* Special feature for tricky drivers */
@@ -3889,7 +3898,7 @@ static int blk_end_io(struct request *rq, int error, int nr_bytes, 
 **/

int blk_end_request(struct request *rq, int error, int nr_bytes)

{

	return blk_end_io(rq, error, nr_bytes, NULL);

	return blk_end_io(rq, error, nr_bytes, 0, NULL);

}

EXPORT_SYMBOL_GPL(blk_end_request);
@@ -3929,6 +3938,27 @@ int __blk_end_request(struct request *rq, int error, int nr_bytes) 
}

EXPORT_SYMBOL_GPL(__blk_end_request);



/**

 * blk_end_bidi_request - Helper function for drivers to complete bidi request.

 * @rq:         the bidi request being processed

 * @error:      0 for success, < 0 for error

 * @nr_bytes:   number of bytes to complete @rq

 * @bidi_bytes: number of bytes to complete @rq->next_rq

 *

 * Description:

 *     Ends I/O on a number of bytes attached to @rq and @rq->next_rq.

 *

 * Return:

 *     0 - we are done with this request

 *     1 - still buffers pending for this request

 **/

int blk_end_bidi_request(struct request *rq, int error, int nr_bytes,

			 int bidi_bytes)

{

	return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL);

}

EXPORT_SYMBOL_GPL(blk_end_bidi_request);



/**

 * blk_end_request_callback - Special helper function for tricky drivers

 * @rq:           the request being processed
@@ -3957,7 +3987,7 @@ EXPORT_SYMBOL_GPL(__blk_end_request); 
int blk_end_request_callback(struct request *rq, int error, int nr_bytes,

			     int (drv_callback)(struct request *))

{

	return blk_end_io(rq, error, nr_bytes, drv_callback);

	return blk_end_io(rq, error, nr_bytes, 0, drv_callback);

}

EXPORT_SYMBOL_GPL(blk_end_request_callback);

include/linux/blkdev.h

+2 −0
Original line number Diff line number Diff line
@@ -728,6 +728,8 @@ static inline void blk_run_address_space(struct address_space *mapping) 
 */

extern int blk_end_request(struct request *rq, int error, int nr_bytes);

extern int __blk_end_request(struct request *rq, int error, int nr_bytes);

extern int blk_end_bidi_request(struct request *rq, int error, int nr_bytes,

				int bidi_bytes);

extern int end_that_request_first(struct request *, int, int);

extern int end_that_request_chunk(struct request *, int, int);

extern void end_that_request_last(struct request *, int);