From 7b4f36cd22a65b750b4cb6ac14804fb7d6e6c67d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 12 Jan 2024 09:12:20 -0700 Subject: [PATCH] block: ensure we hold a queue reference when using queue limits 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 Fixes: 900e08075202 ("block: move queue enter logic into blk_mq_submit_bio()") Reviewed-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- 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 f57b86d6de6a..e02c4b1af8c5 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2964,12 +2964,6 @@ 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) { @@ -2978,6 +2972,11 @@ 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)) @@ -2988,6 +2987,11 @@ 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; }