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, 3 insertions, 5 deletions

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 284b3662d234..4877a0db16c6 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -566,11 +566,6 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 	if (hold_time(br) == 0)
 		return;
 
-	/* ignore packets unless we are using this port */
-	if (!(source->state == BR_STATE_LEARNING ||
-	      source->state == BR_STATE_FORWARDING))
-		return;
-
 	fdb = fdb_find_rcu(&br->fdb_hash_tbl, addr, vid);
 	if (likely(fdb)) {
 		/* attempt to update an entry for a local interface */
@@ -886,6 +881,9 @@ static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
 				br->dev->name);
 			return -EINVAL;
 		}
+		if (!nbp_state_should_learn(p))
+			return 0;
+
 		local_bh_disable();
 		rcu_read_lock();
 		br_fdb_update(br, p, addr, vid, BIT(BR_FDB_ADDED_BY_USER));