Commit 54c8195b authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

iov_iter: optimise bvec iov_iter_advance() 



iov_iter_advance() is heavily used, but implemented through generic
means. For bvecs there is a specifically crafted function for that, so
use bvec_iter_advance() instead, it's faster and slimmer.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ecd7fba0

lib/iov_iter.c

+19 −0
Original line number Diff line number Diff line
@@ -1065,6 +1065,21 @@ static void pipe_advance(struct iov_iter *i, size_t size) 
	pipe_truncate(i);

}



static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)

{

	struct bvec_iter bi;



	bi.bi_size = i->count;

	bi.bi_bvec_done = i->iov_offset;

	bi.bi_idx = 0;

	bvec_iter_advance(i->bvec, &bi, size);



	i->bvec += bi.bi_idx;

	i->nr_segs -= bi.bi_idx;

	i->count = bi.bi_size;

	i->iov_offset = bi.bi_bvec_done;

}



void iov_iter_advance(struct iov_iter *i, size_t size)

{

	if (unlikely(iov_iter_is_pipe(i))) {
@@ -1075,6 +1090,10 @@ void iov_iter_advance(struct iov_iter *i, size_t size) 
		i->count -= size;

		return;

	}

	if (iov_iter_is_bvec(i)) {

		iov_iter_bvec_advance(i, size);

		return;

	}

	iterate_and_advance(i, size, v, 0, 0, 0)

}

EXPORT_SYMBOL(iov_iter_advance);