Commit 7ca44303 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
Browse files

block: add a bio_reuse helper 



Add a helper to allow an existing bio to be resubmitted without
having to re-add the payload.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJens Axboe <axboe@kernel.dk>
Reviewed-by: default avatarHans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent cf9b52fa

block/bio.c

+34 −0
Original line number Diff line number Diff line
@@ -311,6 +311,40 @@ void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf) 
}

EXPORT_SYMBOL(bio_reset);



/**

 * bio_reuse - reuse a bio with the payload left intact

 * @bio:	bio to reuse

 * @opf:	operation and flags for the next I/O

 *

 * Allow reusing an existing bio for another operation with all set up

 * fields including the payload, device and end_io handler left intact.

 *

 * Typically used when @bio is first used to read data which is then written

 * to another location without modification.  @bio must not be in-flight and

 * owned by the caller.  Can't be used for cloned bios.

 *

 * Note: Can't be used when @bio has integrity or blk-crypto contexts for now.

 * Feel free to add that support when you need it, though.

 */

void bio_reuse(struct bio *bio, blk_opf_t opf)

{

	unsigned short vcnt = bio->bi_vcnt, i;

	bio_end_io_t *end_io = bio->bi_end_io;

	void *private = bio->bi_private;



	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));

	WARN_ON_ONCE(bio_integrity(bio));

	WARN_ON_ONCE(bio_has_crypt_ctx(bio));



	bio_reset(bio, bio->bi_bdev, opf);

	for (i = 0; i < vcnt; i++)

		bio->bi_iter.bi_size += bio->bi_io_vec[i].bv_len;

	bio->bi_vcnt = vcnt;

	bio->bi_private = private;

	bio->bi_end_io = end_io;

}

EXPORT_SYMBOL_GPL(bio_reuse);



static struct bio *__bio_chain_endio(struct bio *bio)

{

	struct bio *parent = bio->bi_private;

include/linux/bio.h

+1 −0
Original line number Diff line number Diff line
@@ -414,6 +414,7 @@ static inline void bio_init_inline(struct bio *bio, struct block_device *bdev, 
}

extern void bio_uninit(struct bio *);

void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf);

void bio_reuse(struct bio *bio, blk_opf_t opf);

void bio_chain(struct bio *, struct bio *);



int __must_check bio_add_page(struct bio *bio, struct page *page, unsigned len,