+/* replace an old entry atomically.
+ */
+static inline void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
+{
+ _new->next = old->next;
+ _new->prev = old->prev;
+ rcu_assign_pointer(_new->prev->next, _new);
+ _new->next->prev = _new;
+}