From d0e5fbb01a67e400e82fefe4896ea40c6447ab98 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 23 Jan 2016 08:05:33 +0800 Subject: [PATCH] block: fix bio splitting on max sectors After commit e36f62042880(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: e36f62042880(block: split bios to maxpossible length) Reported-by: Stefan Haberland Cc: Keith Busch Suggested-by: Linus Torvalds Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-merge.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 1699df5..888a7fe 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -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; } - goto split; + if (sectors) + goto split; + /* Make this single bvec as the 1st segment */ } if (bvprvp && blk_queue_cluster(q)) { -- 2.7.4