Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

blk-merge: fix blk_bio_segment_split

Browse source 
Commit bdced438acd83a(block: setup bi_phys_segments after
splitting) introduces function of computing bio->bi_phys_segments
during bio splitting.

Unfortunately both bio->bi_seg_front_size and bio->bi_seg_back_size
arn't computed, so too many physical segments may be obtained
for one request since both the two are used to check if one segment
across two bios can be possible.

This patch fixes the issue by computing the two variables in
blk_bio_segment_split().

Fixes: bdced438acd83a(block: setup bi_phys_segments after splitting)
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Mark Salter <msalter@redhat.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Ming Lei 2015-11-24 10:35:30 +08:00 committed by Jens Axboe
parent 578270bfbd
commit 02e707424c
1 changed files with 19 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
block/blk-merge.c
View file

@ -76,6 +76,9 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
unsigned seg_size = 0, nsegs = 0, sectors = 0;
unsigned front_seg_size = bio->bi_seg_front_size;
bool do_split = true;
struct bio *new = NULL;
bio_for_each_segment(bv, bio, iter) {
if (sectors + (bv.bv_len >> 9) > queue_max_sectors(q))
@ -111,13 +114,26 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bvprvp = &bvprv;
seg_size = bv.bv_len;
sectors += bv.bv_len >> 9;
if (nsegs == 1 && seg_size > front_seg_size)
front_seg_size = seg_size;
}
*segs = nsegs;
return NULL;
do_split = false;
split:
*segs = nsegs;
return bio_split(bio, sectors, GFP_NOIO, bs);
if (do_split) {
new = bio_split(bio, sectors, GFP_NOIO, bs);
if (new)
bio = new;
}
bio->bi_seg_front_size = front_seg_size;
if (seg_size > bio->bi_seg_back_size)
bio->bi_seg_back_size = seg_size;
return do_split ? new : NULL;
}
void blk_queue_split(struct request_queue *q, struct bio **bio,