Commit d0e5fbb0 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: fix bio splitting on max sectors 



After commit e36f6204(block: split bios to maxpossible length),
bio can be splitted in the middle of a vector entry, then it
is easy to split out one bio which size isn't aligned with block
size, especially when the block size is bigger than 512.

This patch fixes the issue by making the max io size aligned
to logical block size.

Fixes: e36f6204(block: split bios to maxpossible length)
Reported-by: default avatarStefan Haberland <sth@linux.vnet.ibm.com>
Cc: Keith Busch <keith.busch@intel.com>
Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent b82dde02

block/blk-merge.c

+19 −7
Original line number Diff line number Diff line
@@ -70,6 +70,18 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q, 
	return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs);

}



static inline unsigned get_max_io_size(struct request_queue *q,

				       struct bio *bio)

{

	unsigned sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector);

	unsigned mask = queue_logical_block_size(q) - 1;



	/* aligned to logical block size */

	sectors &= ~(mask >> 9);



	return sectors;

}



static struct bio *blk_bio_segment_split(struct request_queue *q,

					 struct bio *bio,

					 struct bio_set *bs,
@@ -81,6 +93,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, 
	unsigned front_seg_size = bio->bi_seg_front_size;

	bool do_split = true;

	struct bio *new = NULL;

	const unsigned max_sectors = get_max_io_size(q, bio);



	bio_for_each_segment(bv, bio, iter) {

		/*
@@ -90,20 +103,19 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, 
		if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset))

			goto split;



		if (sectors + (bv.bv_len >> 9) >

				blk_max_size_offset(q, bio->bi_iter.bi_sector)) {

		if (sectors + (bv.bv_len >> 9) > max_sectors) {

			/*

			 * Consider this a new segment if we're splitting in

			 * the middle of this vector.

			 */

			if (nsegs < queue_max_segments(q) &&

			    sectors < blk_max_size_offset(q,

						bio->bi_iter.bi_sector)) {

			    sectors < max_sectors) {

				nsegs++;

				sectors = blk_max_size_offset(q,

						bio->bi_iter.bi_sector);

				sectors = max_sectors;

			}

			if (sectors)

				goto split;

			/* Make this single bvec as the 1st segment */

		}



		if (bvprvp && blk_queue_cluster(q)) {

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