ofproto-dpif: Lock rules to prevent eviction.

[sliver-openvswitch.git] / ofproto / ofproto-provider.h

diff --git a/ofproto/ofproto-provider.h b/ofproto/ofproto-provider.h
index 75bcefc..aa262bc 100644 (file)
--- a/ofproto/ofproto-provider.h
+++ b/ofproto/ofproto-provider.h
@@ -76,7 +76,9 @@ struct ofproto {
 
     /* Optimisation for flow expiry.
      * These flows should all be present in tables. */
-    struct list expirable;      /* Expirable 'struct rule"s in all tables. */
+    struct ovs_mutex expirable_mutex;
+    struct list expirable OVS_GUARDED; /* Expirable 'struct rule"s in all
+                                          tables. */
 
     /* Meter table.
      * OpenFlow meters start at 1.  To avoid confusion we leave the first
@@ -228,10 +230,18 @@ struct rule {
     uint16_t idle_timeout OVS_GUARDED; /* In seconds from ->used. */
 
     /* Eviction groups. */
-    bool evictable;              /* If false, prevents eviction. */
     struct heap_node evg_node;   /* In eviction_group's "rules" heap. */
     struct eviction_group *eviction_group; /* NULL if not in any group. */
 
+    /* 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;
+
     struct ofpact *ofpacts;      /* Sequence of "struct ofpacts". */
     unsigned int ofpacts_len;    /* Size of 'ofpacts', in bytes. */
 
@@ -263,8 +273,10 @@ rule_from_cls_rule(const struct cls_rule *cls_rule)
 }
 
 void ofproto_rule_update_used(struct rule *, long long int used);
-void ofproto_rule_expire(struct rule *, uint8_t reason);
-void ofproto_rule_destroy(struct rule *);
+void ofproto_rule_expire(struct rule *rule, uint8_t reason)
+    OVS_RELEASES(rule->evict);
+void ofproto_rule_destroy(struct ofproto *, struct classifier *cls,
+                          struct rule *) OVS_REQ_WRLOCK(cls->rwlock);
 
 bool ofproto_rule_has_out_port(const struct rule *, ofp_port_t out_port);