+ /*
+ * bfqq does not exist any longer, so it cannot be woken by
+ * any other queue, and cannot wake any other queue. Then bfqq
+ * must be removed from the woken list of its possible waker
+ * queue, and all queues in the woken list of bfqq must stop
+ * having a waker queue. Strictly speaking, these updates
+ * should be performed when bfqq remains with no I/O source
+ * attached to it, which happens before bfqq gets freed. In
+ * particular, this happens when the last process associated
+ * with bfqq exits or gets associated with a different
+ * queue. However, both events lead to bfqq being freed soon,
+ * and dangling references would come out only after bfqq gets
+ * freed. So these updates are done here, as a simple and safe
+ * way to handle all cases.
+ */
+ /* remove bfqq from woken list */
+ if (!hlist_unhashed(&bfqq->woken_list_node))
+ hlist_del_init(&bfqq->woken_list_node);
+
+ /* reset waker for all queues in woken list */
+ hlist_for_each_entry_safe(item, n, &bfqq->woken_list,
+ woken_list_node) {
+ item->waker_bfqq = NULL;
+ bfq_clear_bfqq_has_waker(item);
+ hlist_del_init(&item->woken_list_node);
+ }
+