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Commit d18d9174 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: introduce bio_for_each_bvec() and rq_for_each_bvec() 



bio_for_each_bvec() is used for iterating over multi-page bvec for bio
split & merge code.

rq_for_each_bvec() can be used for drivers which may handle the
multi-page bvec directly, so far loop is one perfect use case.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3d75ca0a

include/linux/bio.h

+10 −0
Original line number Diff line number Diff line
@@ -156,6 +156,16 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter, 
#define bio_for_each_segment(bvl, bio, iter)				\

	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)



#define __bio_for_each_bvec(bvl, bio, iter, start)		\

	for (iter = (start);						\

	     (iter).bi_size &&						\

		((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \

	     bio_advance_iter((bio), &(iter), (bvl).bv_len))



/* iterate over multi-page bvec */

#define bio_for_each_bvec(bvl, bio, iter)			\

	__bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)



#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)



static inline unsigned bio_segments(struct bio *bio)

include/linux/blkdev.h

+4 −0
Original line number Diff line number Diff line
@@ -792,6 +792,10 @@ struct req_iterator { 
	__rq_for_each_bio(_iter.bio, _rq)			\

		bio_for_each_segment(bvl, _iter.bio, _iter.iter)



#define rq_for_each_bvec(bvl, _rq, _iter)			\

	__rq_for_each_bio(_iter.bio, _rq)			\

		bio_for_each_bvec(bvl, _iter.bio, _iter.iter)



#define rq_iter_last(bvec, _iter)				\

		(_iter.bio->bi_next == NULL &&			\

		 bio_iter_last(bvec, _iter.iter))