[PATCH v2 net-next 2/8] net: bridge: switchdev: differentiate new VLANs from changed ones

[Vladimir Oltean <vladimir.oltean@nxp.com>]

br_switchdev_port_vlan_add() currently emits a SWITCHDEV_PORT_OBJ_ADD
event with a SWITCHDEV_OBJ_ID_PORT_VLAN for 2 distinct cases:

- a struct net_bridge_vlan got created
- an existing struct net_bridge_vlan was modified

This makes it impossible for switchdev drivers to properly balance
PORT_OBJ_ADD with PORT_OBJ_DEL events, so if we want to allow that to
happen, we must provide a way for drivers to distinguish between a
VLAN with changed flags and a new one.

Annotate struct switchdev_obj_port_vlan with a "bool changed" that
distinguishes the 2 cases above. If the VLAN is changed, also provide
the old flags such that the driver can determine which flags were
actually changed.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: patch is new, logically replaces the need for "net: bridge:
        vlan: notify a switchdev deletion when modifying flags of
        existing VLAN"

 include/net/switchdev.h   |  6 ++++++
 net/bridge/br_private.h   |  6 ++++--
 net/bridge/br_switchdev.c |  3 +++
 net/bridge/br_vlan.c      | 12 +++++++-----
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index d353793dfeb5..24ec1f82a521 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -79,8 +79,14 @@ struct switchdev_obj {
 /* SWITCHDEV_OBJ_ID_PORT_VLAN */
 struct switchdev_obj_port_vlan {
 	struct switchdev_obj obj;
+	/* Valid only if @changed is set */
+	u16 old_flags;
 	u16 flags;
 	u16 vid;
+	/* If set, the notifier signifies a change of flags for
+	 * a VLAN that already exists.
+	 */
+	bool changed;
 };
 
 #define SWITCHDEV_OBJ_PORT_VLAN(OBJ) \
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 2661dda1a92b..633cc048c590 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1985,6 +1985,7 @@ void br_switchdev_mdb_notify(struct net_device *dev,
 			     struct net_bridge_port_group *pg,
 			     int type);
 int br_switchdev_port_vlan_add(struct net_device *dev, u16 vid, u16 flags,
+			       bool changed, u16 old_flags,
 			       struct netlink_ext_ack *extack);
 int br_switchdev_port_vlan_del(struct net_device *dev, u16 vid);
 void br_switchdev_init(struct net_bridge *br);
@@ -2052,8 +2053,9 @@ static inline int br_switchdev_set_port_flag(struct net_bridge_port *p,
 	return 0;
 }
 
-static inline int br_switchdev_port_vlan_add(struct net_device *dev,
-					     u16 vid, u16 flags,
+static inline int br_switchdev_port_vlan_add(struct net_device *dev, u16 vid,
+					     u16 flags, bool changed,
+					     u16 old_flags,
 					     struct netlink_ext_ack *extack)
 {
 	return -EOPNOTSUPP;
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index f8fbaaa7c501..f36f60766478 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -160,6 +160,7 @@ br_switchdev_fdb_notify(struct net_bridge *br,
 }
 
 int br_switchdev_port_vlan_add(struct net_device *dev, u16 vid, u16 flags,
+			       bool changed, u16 old_flags,
 			       struct netlink_ext_ack *extack)
 {
 	struct switchdev_obj_port_vlan v = {
@@ -167,6 +168,8 @@ int br_switchdev_port_vlan_add(struct net_device *dev, u16 vid, u16 flags,
 		.obj.id = SWITCHDEV_OBJ_ID_PORT_VLAN,
 		.flags = flags,
 		.vid = vid,
+		.changed = changed,
+		.old_flags = old_flags,
 	};
 
 	return switchdev_port_obj_add(dev, &v.obj, extack);
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index c5355695c976..6f3ee4d8fea8 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -105,7 +105,7 @@ static int __vlan_vid_add(struct net_device *dev, struct net_bridge *br,
 	/* Try switchdev op first. In case it is not supported, fallback to
 	 * 8021q add.
 	 */
-	err = br_switchdev_port_vlan_add(dev, v->vid, flags, extack);
+	err = br_switchdev_port_vlan_add(dev, v->vid, flags, false, 0, extack);
 	if (err == -EOPNOTSUPP)
 		return vlan_vid_add(dev, br->vlan_proto, v->vid);
 	v->priv_flags |= BR_VLFLAG_ADDED_BY_SWITCHDEV;
@@ -297,7 +297,8 @@ static int __vlan_add(struct net_bridge_vlan *v, u16 flags,
 		}
 		br_multicast_port_ctx_init(p, v, &v->port_mcast_ctx);
 	} else {
-		err = br_switchdev_port_vlan_add(dev, v->vid, flags, extack);
+		err = br_switchdev_port_vlan_add(dev, v->vid, flags, false, 0,
+						 extack);
 		if (err && err != -EOPNOTSUPP)
 			goto out;
 		br_multicast_ctx_init(br, v, &v->br_mcast_ctx);
@@ -688,7 +689,7 @@ static int br_vlan_add_existing(struct net_bridge *br,
 	*changed = __vlan_flags_would_change(vlan, flags);
 	if (*changed) {
 		err = br_switchdev_port_vlan_add(br->dev, vlan->vid, flags,
-						 extack);
+						 true, vlan->flags, extack);
 		if (err && err != -EOPNOTSUPP)
 			return err;
 	}
@@ -1266,8 +1267,9 @@ int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags,
 		*changed = __vlan_flags_would_change(vlan, flags);
 		if (*changed) {
 			/* Pass the flags to the hardware bridge */
-			ret = br_switchdev_port_vlan_add(port->dev, vid,
-							 flags, extack);
+			ret = br_switchdev_port_vlan_add(port->dev, vid, flags,
+							 true, vlan->flags,
+							 extack);
 			if (ret && ret != -EOPNOTSUPP)
 				return ret;
 		}
-- 
2.25.1