bridge: add tracepoint in br_fdb_update

This extends bridge fdb table tracepoints to also cover
learned fdb entries in the br_fdb_update path. Note that
unlike other tracepoints I have moved this to when the fdb
is modified because this is in the datapath and can generate
a lot of noise in the trace output. br_fdb_update is also called
from added_by_user context in the NTF_USE case which is already
traced ..hence the !added_by_user check.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/trace/events/bridge.h

@@ -92,6 +92,37 @@ TRACE_EVENT(fdb_delete,
 		  __entry->addr[4], __entry->addr[5], __entry->vid)
 );
 
+TRACE_EVENT(br_fdb_update,
+
+	TP_PROTO(struct net_bridge *br, struct net_bridge_port *source,
+		 const unsigned char *addr, u16 vid, bool added_by_user),
+
+	TP_ARGS(br, source, addr, vid, added_by_user),
+
+	TP_STRUCT__entry(
+		__string(br_dev, br->dev->name)
+		__string(dev, source->dev->name)
+		__array(unsigned char, addr, ETH_ALEN)
+		__field(u16, vid)
+		__field(bool, added_by_user)
+	),
+
+	TP_fast_assign(
+		__assign_str(br_dev, br->dev->name);
+		__assign_str(dev, source->dev->name);
+		memcpy(__entry->addr, addr, ETH_ALEN);
+		__entry->vid = vid;
+		__entry->added_by_user = added_by_user;
+	),
+
+	TP_printk("br_dev %s source %s addr %02x:%02x:%02x:%02x:%02x:%02x vid %u added_by_user %d",
+		  __get_str(br_dev), __get_str(dev), __entry->addr[0],
+		  __entry->addr[1], __entry->addr[2], __entry->addr[3],
+		  __entry->addr[4], __entry->addr[5], __entry->vid,
+		  __entry->added_by_user)
+);
+
+
 #endif /* _TRACE_BRIDGE_H */
 
 /* This part must be outside protection */

net/bridge/br_fdb.c

@@ -583,9 +583,11 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 				fdb->updated = now;
 			if (unlikely(added_by_user))
 				fdb->added_by_user = 1;
-			if (unlikely(fdb_modified))
+			if (unlikely(fdb_modified)) {
+				trace_br_fdb_update(br, source, addr, vid, added_by_user);
 				fdb_notify(br, fdb, RTM_NEWNEIGH);
 			}
+		}
 	} else {
 		spin_lock(&br->hash_lock);
 		if (likely(!fdb_find_rcu(head, addr, vid))) {
@@ -593,6 +595,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 			if (fdb) {
 				if (unlikely(added_by_user))
 					fdb->added_by_user = 1;
+				trace_br_fdb_update(br, source, addr, vid, added_by_user);
 				fdb_notify(br, fdb, RTM_NEWNEIGH);
 			}
 		}

net/core/net-traces.c

@@ -42,6 +42,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(fib6_table_lookup);
 EXPORT_TRACEPOINT_SYMBOL_GPL(br_fdb_add);
 EXPORT_TRACEPOINT_SYMBOL_GPL(br_fdb_external_learn_add);
 EXPORT_TRACEPOINT_SYMBOL_GPL(fdb_delete);
+EXPORT_TRACEPOINT_SYMBOL_GPL(br_fdb_update);
 #endif
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);