Commit fd7d8d42 authored Mar 17, 2019 by Ming Lei Committed by Jens Axboe Apr 01, 2019

block: don't merge adjacent bvecs to one segment in bio blk_queue_split

For normal filesystem IO, each page is added via blk_add_page(),
in which bvec(page) merge has been handled already, and basically
not possible to merge two adjacent bvecs in one bio.

So not try to merge two adjacent bvecs in blk_queue_split().

Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent db5ebd6e

block/blk-merge.c

+0 −17

Original line number	Diff line number	Diff line
		@@ -267,23 +267,6 @@ static struct bio blk_bio_segment_split(struct request_queue q,
		goto split;
		}

		if (bvprvp) {
		if (seg_size + bv.bv_len > queue_max_segment_size(q))
		goto new_segment;
		if (!biovec_phys_mergeable(q, bvprvp, &bv))
		goto new_segment;

		seg_size += bv.bv_len;
		bvprv = bv;
		bvprvp = &bvprv;
		sectors += bv.bv_len >> 9;

		if (nsegs == 1 && seg_size > front_seg_size)
		front_seg_size = seg_size;

		continue;
		}
		new_segment:
		if (nsegs == max_segs)
		goto split;

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