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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: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Kiyoshi Ueda 2007-12-11 17:51:46 -05:00 committed by Jens Axboe
parent aaa04c28cb
commit e3a04fe34a
2 changed files with 37 additions and 5 deletions
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40
block/ll_rw_blk.c
View File

@ -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);

2
include/linux/blkdev.h
View File

@ -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);