+ ovs_mutex_unlock(&dpif_mutex);
+}
+
+static void
+dp_class_unref(struct registered_dpif_class *rc)
+{
+ ovs_mutex_lock(&dpif_mutex);
+ ovs_assert(rc->refcount);
+ rc->refcount--;
+ ovs_mutex_unlock(&dpif_mutex);
+}
+
+static struct registered_dpif_class *
+dp_class_lookup(const char *type)
+{
+ struct registered_dpif_class *rc;
+
+ ovs_mutex_lock(&dpif_mutex);
+ rc = shash_find_data(&dpif_classes, type);
+ if (rc) {
+ rc->refcount++;
+ }
+ ovs_mutex_unlock(&dpif_mutex);
+
+ return rc;