block: call rq_qos_exit() after queue is frozen

rq_qos_exit() removes the current q->rq_qos, this action has to be
done after queue is frozen, otherwise the IO queue path may never
be waken up, then IO hang is caused.

So fixes this issue by moving rq_qos_exit() after queue is frozen.

Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index bc6ea87d10e02cffcaedec7cc9d4567d88cdd6b6..26a5dac80ed9898a14d6da3d637f25f77fda53e7 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -785,6 +785,9 @@ void blk_cleanup_queue(struct request_queue *q)
         * prevent that q->request_fn() gets invoked after draining finished.
         */
        blk_freeze_queue(q);
+
+       rq_qos_exit(q);
+
        spin_lock_irq(lock);
        queue_flag_set(QUEUE_FLAG_DEAD, q);
        spin_unlock_irq(lock);

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 0641533597f1b2cc389e6579a986d6df17115646..844a454a7b3a60a0c3186b589ab12daad0e9b3b8 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -1007,8 +1007,6 @@ void blk_unregister_queue(struct gendisk *disk)
        kobject_del(&q->kobj);
        blk_trace_remove_sysfs(disk_to_dev(disk));
 
-       rq_qos_exit(q);
-
        mutex_lock(&q->sysfs_lock);
        if (q->request_fn || (q->mq_ops && q->elevator))
                elv_unregister_queue(q);