- * We keep two dummy nodes in the queue to distinguish between empty queue
- * state and intermediate state while a dummy node dequeue/requeue is
- * being performed. Dequeue retry if it detects that it would be
- * dequeueing the last node (it means a dummy node dequeue-requeue is in
- * progress). This ensures that there is always at least one node in
- * the queue. In a situation where the two dummy nodes are being
- * requeued (they therefore don't appear in the queue at a given
- * moment), we are certain that there is at least one non-dummy node in
- * the queue (ensured by the test for NULL next node upon dequeue).
+ * Dequeue retry if it detects that it would be dequeueing the last node
+ * (it means a dummy node dequeue-requeue is in progress). This ensures
+ * that there is always at least one node in the queue.