diff options
| -rw-r--r-- | block/blk-core.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 4234332aa23c..6373febc7716 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -669,6 +669,15 @@ int blk_queue_enter(struct request_queue *q, bool nowait) if (nowait) return -EBUSY; + /* + * read pair of barrier in blk_mq_freeze_queue_start(), + * we need to order reading __PERCPU_REF_DEAD flag of + * .q_usage_counter and reading .mq_freeze_depth, + * otherwise the following wait may never return if the + * two reads are reordered. + */ + smp_rmb(); + ret = wait_event_interruptible(q->mq_freeze_wq, !atomic_read(&q->mq_freeze_depth) || blk_queue_dying(q)); |