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authorJens Axboe <axboe@kernel.dk>2024-01-12 17:12:20 +0100
committerJens Axboe <axboe@kernel.dk>2024-01-13 05:09:42 +0100
commit7b4f36cd22a65b750b4cb6ac14804fb7d6e6c67d (patch)
tree864387a9062eca7d66d11bcc685c81dc1b9fa7f6 /block/blk-mq.c
parentblk-mq: rename blk_mq_can_use_cached_rq (diff)
downloadlinux-7b4f36cd22a65b750b4cb6ac14804fb7d6e6c67d.tar.xz
linux-7b4f36cd22a65b750b4cb6ac14804fb7d6e6c67d.zip
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 <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>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c16
1 files 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;
}