6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jens Axboe <axboe@xxxxxxxxx>
[ Upstream commit 7b4f36cd22a65b750b4cb6ac14804fb7d6e6c67d ]
q_usage_counter is the only thing preventing us from the limits changing
under us in __bio_split_to_limits, but blk_mq_submit_bio doesn't hold
it while calling into it.
Move the splitting inside the region where we know we've got a queue
reference. Ideally this could still remain a shared section of code, but
let's keep the fix simple and defer any refactoring here to later.
Reported-by: Christoph Hellwig <hch@xxxxxx>
Fixes: 900e08075202 ("block: move queue enter logic into blk_mq_submit_bio()")
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
block/blk-mq.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 368f1947c895..b3f99dda4530 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2946,12 +2946,6 @@ void blk_mq_submit_bio(struct bio *bio)
blk_status_t ret;
bio = blk_queue_bounce(bio, q);
- if (bio_may_exceed_limits(bio, &q->limits)) {
- bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
- if (!bio)
- return;
- }
-
bio_set_ioprio(bio);
if (plug) {
@@ -2960,6 +2954,11 @@ void blk_mq_submit_bio(struct bio *bio)
rq = NULL;
}
if (rq) {
+ if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
+ bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
+ if (!bio)
+ return;
+ }
if (!bio_integrity_prep(bio))
return;
if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
@@ -2970,6 +2969,11 @@ void blk_mq_submit_bio(struct bio *bio)
} else {
if (unlikely(bio_queue_enter(bio)))
return;
+ if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
+ bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
+ if (!bio)
+ goto fail;
+ }
if (!bio_integrity_prep(bio))
goto fail;
}
--
2.43.0
