struct Qdisc *qdisc_default = _qdisc_default;
 
        if (qdisc) {
+               spinlock_t *root_lock = qdisc_root_lock(qdisc);
+
                dev_queue->qdisc = qdisc_default;
                dev_queue->qdisc_sleeping = qdisc_default;
 
+               spin_lock(root_lock);
                qdisc_destroy(qdisc);
+               spin_unlock(root_lock);
        }
 }
 
 void dev_shutdown(struct net_device *dev)
 {
-       qdisc_lock_tree(dev);
        netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
        shutdown_scheduler_queue(dev, &dev->rx_queue, NULL);
        BUG_TRAP(!timer_pending(&dev->watchdog_timer));
-       qdisc_unlock_tree(dev);
 }