net: bridge: fdb: eliminate extra port state tests from fast-path

When commit df1c0b8468b3 ("[BRIDGE]: Packets leaking out of
disabled/blocked ports.") introduced the port state tests in
br_fdb_update() it was to avoid learning/refreshing from STP BPDUs, it was
also used to avoid learning/refreshing from user-space with NTF_USE. Those
two tests are done for every packet entering the bridge if it's learning,
but for the fast-path we already have them checked in br_handle_frame() and
is unnecessary to do it again. Thus push the checks to the unlikely cases
and drop them from br_fdb_update(), the new nbp_state_should_learn() helper
is used to determine if the port state allows br_fdb_update() to be called.
The two places which need to do it manually are:
 - user-space add call with NTF_USE set
 - link-local packet learning done in __br_handle_local_finish()

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 08742bff9bf0..36b0367ca1e0 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -500,6 +500,11 @@ static inline bool br_vlan_should_use(const struct net_bridge_vlan *v)
 	return true;
 }
 
+static inline bool nbp_state_should_learn(const struct net_bridge_port *p)
+{
+	return p->state == BR_STATE_LEARNING || p->state == BR_STATE_FORWARDING;
+}
+
 static inline int br_opt_get(const struct net_bridge *br,
 			     enum net_bridge_opts opt)
 {