diff --git a/block/elevator.c b/block/elevator.c index 4400eb8fe54f..2e18513dcd73 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -723,6 +723,7 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, int ret; unsigned int memflags; struct request_queue *q = disk->queue; + struct blk_mq_tag_set *set = q->tag_set; /* * If the attribute needs to load a module, do it before freezing the @@ -734,6 +735,7 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, elv_iosched_load_module(name); + down_read(&set->update_nr_hwq_lock); memflags = blk_mq_freeze_queue(q); mutex_lock(&q->elevator_lock); ret = elevator_change(q, name); @@ -741,6 +743,7 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, ret = count; mutex_unlock(&q->elevator_lock); blk_mq_unfreeze_queue(q, memflags); + up_read(&set->update_nr_hwq_lock); return ret; }