Commit 22b56c29 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

bio: optimise bvec iteration 



__bio_for_each_bvec(), __bio_for_each_segment() and bio_copy_data_iter()
fall under conditions of bvec_iter_advance_single(), which is a faster
and slimmer version of bvec_iter_advance(). Add
bio_advance_iter_single() and convert them.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 6b6667aa

block/bio.c

+2 −2
Original line number Diff line number Diff line
@@ -1212,8 +1212,8 @@ void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, 


		flush_dcache_page(dst_bv.bv_page);



		bio_advance_iter(src, src_iter, bytes);

		bio_advance_iter(dst, dst_iter, bytes);

		bio_advance_iter_single(src, src_iter, bytes);

		bio_advance_iter_single(dst, dst_iter, bytes);

	}

}

EXPORT_SYMBOL(bio_copy_data_iter);

include/linux/bio.h

+15 −2
Original line number Diff line number Diff line
@@ -148,11 +148,24 @@ static inline void bio_advance_iter(const struct bio *bio, 
		/* TODO: It is reasonable to complete bio with error here. */

}



/* @bytes should be less or equal to bvec[i->bi_idx].bv_len */

static inline void bio_advance_iter_single(const struct bio *bio,

					   struct bvec_iter *iter,

					   unsigned int bytes)

{

	iter->bi_sector += bytes >> 9;



	if (bio_no_advance_iter(bio))

		iter->bi_size -= bytes;

	else

		bvec_iter_advance_single(bio->bi_io_vec, iter, bytes);

}



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

	for (iter = (start);						\

	     (iter).bi_size &&						\

		((bvl = bio_iter_iovec((bio), (iter))), 1);		\

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

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



#define bio_for_each_segment(bvl, bio, iter)				\

	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
@@ -161,7 +174,7 @@ static inline void bio_advance_iter(const struct bio *bio, 
	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))

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



/* iterate over multi-page bvec */

#define bio_for_each_bvec(bvl, bio, iter)			\

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