bridge: switchdev: Notify about VLAN protocol changes

Drivers that support bridge offload need to be notified about changes to
the bridge's VLAN protocol so that they could react accordingly and
potentially veto the change.

Add a new switchdev attribute to communicate the change to drivers.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/switchdev.h

@@ -38,6 +38,7 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_PORT_MROUTER,
 	SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
 	SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING,
+	SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL,
 	SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED,
 	SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
 #if IS_ENABLED(CONFIG_BRIDGE_MRP)
@@ -58,6 +59,7 @@ struct switchdev_attr {
 		bool mrouter;				/* PORT_MROUTER */
 		clock_t ageing_time;			/* BRIDGE_AGEING_TIME */
 		bool vlan_filtering;			/* BRIDGE_VLAN_FILTERING */
+		u16 vlan_protocol;			/* BRIDGE_VLAN_PROTOCOL */
 		bool mc_disabled;			/* MC_DISABLED */
 #if IS_ENABLED(CONFIG_BRIDGE_MRP)
 		u8 mrp_port_state;			/* MRP_PORT_STATE */

net/bridge/br_vlan.c

@@ -854,15 +854,25 @@ EXPORT_SYMBOL_GPL(br_vlan_get_proto);
 
 int __br_vlan_set_proto(struct net_bridge *br, __be16 proto)
 {
+	struct switchdev_attr attr = {
+		.orig_dev = br->dev,
+		.id = SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL,
+		.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP,
+		.u.vlan_protocol = ntohs(proto),
+	};
 	int err = 0;
 	struct net_bridge_port *p;
 	struct net_bridge_vlan *vlan;
 	struct net_bridge_vlan_group *vg;
-	__be16 oldproto;
+	__be16 oldproto = br->vlan_proto;
 
 	if (br->vlan_proto == proto)
 		return 0;
 
+	err = switchdev_port_attr_set(br->dev, &attr);
+	if (err && err != -EOPNOTSUPP)
+		return err;
+
 	/* Add VLANs for the new proto to the device filter. */
 	list_for_each_entry(p, &br->port_list, list) {
 		vg = nbp_vlan_group(p);
@@ -873,7 +883,6 @@ int __br_vlan_set_proto(struct net_bridge *br, __be16 proto)
 		}
 	}
 
-	oldproto = br->vlan_proto;
 	br->vlan_proto = proto;
 
 	recalculate_group_addr(br);
@@ -889,6 +898,9 @@ int __br_vlan_set_proto(struct net_bridge *br, __be16 proto)
 	return 0;
 
 err_filt:
+	attr.u.vlan_protocol = ntohs(oldproto);
+	switchdev_port_attr_set(br->dev, &attr);
+
 	list_for_each_entry_continue_reverse(vlan, &vg->vlan_list, vlist)
 		vlan_vid_del(p->dev, proto, vlan->vid);