From: Jianchao Wang <jianchao.w.wang@oracle.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Jianchao Wang <jianchao.w.wang@oracle.com>
Subject: [PATCH] block: move sanity checking ahead of bi_front/back_seg_size updating
Date: Sat, 16 Sep 2017 07:10:30 +0800 [thread overview]
Message-ID: <1505517030-29287-1-git-send-email-jianchao.w.wang@oracle.com> (raw)
If the bio_integrity_merge_rq() return false or nr_phys_segments exceeds
the max_segments, the merging fails, but the bi_front/back_seg_size may
have been modified. To avoid it, move the sanity checking ahead.
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
block/blk-merge.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 99038830..14b6e37 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -553,6 +553,7 @@ static bool req_no_special_merge(struct request *req)
static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
struct request *next)
{
+ bool contig;
int total_phys_segments;
unsigned int seg_size =
req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size;
@@ -575,13 +576,9 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
return 0;
total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
- if (blk_phys_contig_segment(q, req->biotail, next->bio)) {
- if (req->nr_phys_segments == 1)
- req->bio->bi_seg_front_size = seg_size;
- if (next->nr_phys_segments == 1)
- next->biotail->bi_seg_back_size = seg_size;
+ contig = blk_phys_contig_segment(q, req->biotail, next->bio);
+ if (contig)
total_phys_segments--;
- }
if (total_phys_segments > queue_max_segments(q))
return 0;
@@ -589,6 +586,13 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
if (blk_integrity_merge_rq(q, req, next) == false)
return 0;
+ if (contig) {
+ if (req->nr_phys_segments == 1)
+ req->bio->bi_seg_front_size = seg_size;
+ if (next->nr_phys_segments == 1)
+ next->biotail->bi_seg_back_size = seg_size;
+ }
+
/* Merge is OK... */
req->nr_phys_segments = total_phys_segments;
return 1;
--
2.7.4
next reply other threads:[~2017-09-15 7:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 23:10 Jianchao Wang [this message]
2017-09-18 23:51 ` Christoph Hellwig
2017-09-19 0:55 ` jianchao.wang
2017-09-19 14:36 ` Christoph Hellwig
2017-09-20 1:38 ` jianchao.wang
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