6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
[ 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@lst.de Fixes: 900e08075202 ("block: move queue enter logic into blk_mq_submit_bio()") Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }