[PATCH 2/2] bio: optimise bvec iteration
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2020-11-24 18:01:59
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
__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: Pavel Begunkov <asml.silence@gmail.com> --- block/bio.c | 4 ++-- include/linux/bio.h | 17 +++++++++++++++-- 2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index fa01bef35bb1..8e718920457a 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -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);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index c6d765382926..d55d53c49ae4 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h@@ -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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2.24.0