bridge: netlink: add fdb flush

Simple attribute that flushes the bridge's fdb.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index eaeaac1..9ca9bf8 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -244,6 +244,7 @@
 	IFLA_BR_TOPOLOGY_CHANGE_TIMER,
 	IFLA_BR_GC_TIMER,
 	IFLA_BR_GROUP_ADDR,
+	IFLA_BR_FDB_FLUSH,
 	__IFLA_BR_MAX,
 };
 
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index a05a430..5853c57 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -859,6 +859,9 @@
 		br_recalculate_fwd_mask(br);
 	}
 
+	if (data[IFLA_BR_FDB_FLUSH])
+		br_fdb_flush(br);
+
 	return 0;
 }