path: root/block/elevator.c
diff options
authorMing Lei <>2018-01-06 16:27:38 +0800
committerJens Axboe <>2018-01-06 09:25:36 -0700
commit24f5a90f0d13a97b51aa79f468143fafea4246bb (patch)
tree4fe0235db1e0e32b1945933df172ca91456ced78 /block/elevator.c
parentc2856ae2f315d754a0b6a268e4c6745b332b42e7 (diff)
blk-mq: quiesce queue during switching io sched and updating nr_requests
Dispatch may still be in-progress after queue is frozen, so we have to quiesce queue before switching IO scheduler and updating nr_requests. Also when switching io schedulers, blk_mq_run_hw_queue() may still be called somewhere(such as from nvme_reset_work()), and io scheduler's per-hctx data may not be setup yet, so cause oops even inside blk_mq_hctx_has_pending(), such as it can be run just between: ret = e->, e); AND ret = e->, i) inside blk_mq_init_sched(). This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue() after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending won't be called if queue is quiesced. Reviewed-by: Christoph Hellwig <> Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen) Reported-by: Yi Zhang <> Tested-by: Yi Zhang <> Signed-off-by: Ming Lei <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/elevator.c')
1 files changed, 2 insertions, 0 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 7bda083..138faeb 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -968,6 +968,7 @@ static int elevator_switch_mq(struct request_queue *q,
int ret;
+ blk_mq_quiesce_queue(q);
if (q->elevator) {
if (q->elevator->registered)
@@ -994,6 +995,7 @@ static int elevator_switch_mq(struct request_queue *q,
blk_add_trace_msg(q, "elv switch: none");
+ blk_mq_unquiesce_queue(q);
return ret;