mac-learning: Reference count 'struct mac_learning".

Signed-off-by: Ethan Jackson <ethan@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

4 files changed, 25 insertions, 6 deletions

diff --git a/lib/learning-switch.c b/lib/learning-switch.c
index 426cb375c..f2b331904 100644
--- a/lib/learning-switch.c
+++ b/lib/learning-switch.c
@@ -237,7 +237,7 @@ lswitch_destroy(struct lswitch *sw)
             free(node);
         }
         shash_destroy(&sw->queue_names);
-        mac_learning_destroy(sw->ml);
+        mac_learning_unref(sw->ml);
         rconn_packet_counter_destroy(sw->queued);
         free(sw);
     }
diff --git a/lib/mac-learning.c b/lib/mac-learning.c
index f9b3171cf..ca0ccb8e1 100644
--- a/lib/mac-learning.c
+++ b/lib/mac-learning.c
@@ -124,14 +124,31 @@ mac_learning_create(unsigned int idle_time)
     ml->idle_time = normalize_idle_time(idle_time);
     ml->max_entries = MAC_DEFAULT_MAX;
     tag_set_init(&ml->tags);
+    ml->ref_cnt = 1;
     return ml;
 }
 
-/* Destroys MAC learning table 'ml'. */
-void
-mac_learning_destroy(struct mac_learning *ml)
+struct mac_learning *
+mac_learning_ref(const struct mac_learning *ml_)
 {
+    struct mac_learning *ml = CONST_CAST(struct mac_learning *, ml_);
     if (ml) {
+        ovs_assert(ml->ref_cnt > 0);
+        ml->ref_cnt++;
+    }
+    return ml;
+}
+
+/* Unreferences (and possibly destroys) MAC learning table 'ml'. */
+void
+mac_learning_unref(struct mac_learning *ml)
+{
+    if (!ml) {
+        return;
+    }
+
+    ovs_assert(ml->ref_cnt > 0);
+    if (!--ml->ref_cnt) {
         struct mac_entry *e, *next;
 
         HMAP_FOR_EACH_SAFE (e, next, hmap_node, &ml->table) {
diff --git a/lib/mac-learning.h b/lib/mac-learning.h
index 9feca0057..06e99f3db 100644
--- a/lib/mac-learning.h
+++ b/lib/mac-learning.h
@@ -86,11 +86,13 @@ struct mac_learning {
     unsigned int idle_time;     /* Max age before deleting an entry. */
     size_t max_entries;         /* Max number of learned MACs. */
     struct tag_set tags;        /* Tags which have changed. */
+    int ref_cnt;
 };
 
 /* Basics. */
 struct mac_learning *mac_learning_create(unsigned int idle_time);
-void mac_learning_destroy(struct mac_learning *);
+struct mac_learning *mac_learning_ref(const struct mac_learning *);
+void mac_learning_unref(struct mac_learning *);
 
 void mac_learning_run(struct mac_learning *, struct tag_set *);
 void mac_learning_wait(struct mac_learning *);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 87b44f25c..d0e1b4c05 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1197,7 +1197,7 @@ destruct(struct ofproto *ofproto_)
     netflow_destroy(ofproto->netflow);
     dpif_sflow_destroy(ofproto->sflow);
     hmap_destroy(&ofproto->bundles);
-    mac_learning_destroy(ofproto->ml);
+    mac_learning_unref(ofproto->ml);
 
     classifier_destroy(&ofproto->facets);