net: bridge: BROPT_FDB_LOCAL_VLAN_0: On bridge changeaddr, skip per-VLAN FDBs

When BROPT_FDB_LOCAL_VLAN_0 is enabled, the local FDB entries for the
bridge itself should not be created per-VLAN, but instead only on VLAN 0.
When the bridge address changes, the local FDB entries need to be updated,
which is done in br_fdb_change_mac_address().

Bail out early when in VLAN-0 mode, so that the per-VLAN FDB entries are
not created. The per-VLAN walk is only done afterwards.

Reviewed-by: Ido Schimmel <[email protected]>
Signed-off-by: Petr Machata <[email protected]>
Acked-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/0bd432cf91921ef7c4ed0e129de1d1cd358c716b.1757004393.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <[email protected]>

Author: pmachata

net/bridge/br_fdb.c

@@ -503,6 +503,9 @@ void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_fdb_entry *f;
 	struct net_bridge_vlan *v;
+	bool local_vlan_0;
+
+	local_vlan_0 = br_opt_get(br, BROPT_FDB_LOCAL_VLAN_0);
 
 	spin_lock_bh(&br->hash_lock);
 
@@ -514,7 +517,7 @@ void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
 
 	fdb_add_local(br, NULL, newaddr, 0);
 	vg = br_vlan_group(br);
-	if (!vg || !vg->num_vlans)
+	if (!vg || !vg->num_vlans || local_vlan_0)
 		goto out;
 	/* Now remove and add entries for every VLAN configured on the
 	 * bridge.  This function runs under RTNL so the bitmap will not