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Commit 79eb63e9 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by Jens Axboe
Browse files

block: Add blk_make_request(), takes bio, returns a request 



New block API:
given a struct bio allocates a new request. This is the parallel of
generic_make_request for BLOCK_PC commands users.

The passed bio may be a chained-bio. The bio is bounced if needed
inside the call to this member.

This is in the effort of un-exporting blk_rq_append_bio().

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
CC: Jeff Garzik <jeff@garzik.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent bc38bf10

block/blk-core.c

+45 −0
Original line number Diff line number Diff line
@@ -890,6 +890,51 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) 
}

EXPORT_SYMBOL(blk_get_request);



/**

 * blk_make_request - given a bio, allocate a corresponding struct request.

 *

 * @bio:  The bio describing the memory mappings that will be submitted for IO.

 *        It may be a chained-bio properly constructed by block/bio layer.

 *

 * blk_make_request is the parallel of generic_make_request for BLOCK_PC

 * type commands. Where the struct request needs to be farther initialized by

 * the caller. It is passed a &struct bio, which describes the memory info of

 * the I/O transfer.

 *

 * The caller of blk_make_request must make sure that bi_io_vec

 * are set to describe the memory buffers. That bio_data_dir() will return

 * the needed direction of the request. (And all bio's in the passed bio-chain

 * are properly set accordingly)

 *

 * If called under none-sleepable conditions, mapped bio buffers must not

 * need bouncing, by calling the appropriate masked or flagged allocator,

 * suitable for the target device. Otherwise the call to blk_queue_bounce will

 * BUG.

 */

struct request *blk_make_request(struct request_queue *q, struct bio *bio,

				 gfp_t gfp_mask)

{

	struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);



	if (unlikely(!rq))

		return ERR_PTR(-ENOMEM);



	for_each_bio(bio) {

		struct bio *bounce_bio = bio;

		int ret;



		blk_queue_bounce(q, &bounce_bio);

		ret = blk_rq_append_bio(q, rq, bounce_bio);

		if (unlikely(ret)) {

			blk_put_request(rq);

			return ERR_PTR(ret);

		}

	}



	return rq;

}

EXPORT_SYMBOL(blk_make_request);



/**

 * blk_requeue_request - put a request back on queue

 * @q:		request queue where request should be inserted

include/linux/blkdev.h

+2 −0
Original line number Diff line number Diff line
@@ -740,6 +740,8 @@ extern void blk_rq_init(struct request_queue *q, struct request *rq); 
extern void blk_put_request(struct request *);

extern void __blk_put_request(struct request_queue *, struct request *);

extern struct request *blk_get_request(struct request_queue *, int, gfp_t);

extern struct request *blk_make_request(struct request_queue *, struct bio *,

					gfp_t);

extern void blk_insert_request(struct request_queue *, struct request *, int, void *);

extern void blk_requeue_request(struct request_queue *, struct request *);

extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);