blk-mq: Fix memory leak in blk_mq_init_allocated_queue error handling

If blk_mq_init_allocated_queue->elevator_init_mq fails, need to release
the previously requested resources.

Fixes: d3484991 ("blk-mq-sched: allow setting of default IO scheduler")
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -2846,6 +2846,8 @@ static unsigned int nr_hw_queues(struct blk_mq_tag_set *set)
 struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 						  struct request_queue *q)
 {
+	int ret = -ENOMEM;
+
 	/* mark the queue as mq asap */
 	q->mq_ops = set->ops;
 
@@ -2907,17 +2909,18 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 	blk_mq_map_swqueue(q);
 
 	if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
-		int ret;
-
 		ret = elevator_init_mq(q);
 		if (ret)
-			return ERR_PTR(ret);
+			goto err_tag_set;
 	}
 
 	return q;
 
+err_tag_set:
+	blk_mq_del_queue_tag_set(q);
 err_hctxs:
 	kfree(q->queue_hw_ctx);
+	q->nr_hw_queues = 0;
 err_sys_init:
 	blk_mq_sysfs_deinit(q);
 err_poll: