+ /* The evict lock is used to prevent rules from being evicted while child
+ * threads are using them to xlate flows. A read lock means the rule is
+ * currently being used. A write lock means the rule is in the process of
+ * being evicted and should be considered gone. A rule will not be evicted
+ * unless both its own and its classifiers write locks are held.
+ * Therefore, while holding a classifier readlock, one can be assured that
+ * even write locked rules are safe. */
+ struct ovs_rwlock evict;
+