net: dsa: fix switchdev objects on bridge master mistakenly being applied on ports

Tobias reports that after the blamed patch, VLAN objects being added to
a bridge device are being added to all slave ports instead (swp2, swp3).

ip link add br0 type bridge vlan_filtering 1
ip link set swp2 master br0
ip link set swp3 master br0
bridge vlan add dev br0 vid 100 self

This is because the fix was too broad: we made dsa_port_offloads_netdev
say "yes, I offload the br0 bridge" for all slave ports, but we didn't
add the checks whether the switchdev object was in fact meant for the
physical port or for the bridge itself. So we are reacting on events in
a way in which we shouldn't.

The reason why the fix was too broad is because the question itself,
"does this DSA port offload this netdev", was too broad in the first
place. The solution is to disambiguate the question and separate it into
two different functions, one to be called for each switchdev attribute /
object that has an orig_dev == net_bridge (dsa_port_offloads_bridge),
and the other for orig_dev == net_bridge_port (*_offloads_bridge_port).

In the case of VLAN objects on the bridge interface, this solves the
problem because we know that VLAN objects are per bridge port and not
per bridge. And when orig_dev is equal to the net_bridge, we offload it
as a bridge, but not as a bridge port; that's how we are able to skip
reacting on those events. Note that this is compatible with future plans
to have explicit offloading of VLAN objects on the bridge interface as a
bridge port (in DSA, this signifies that we should add that VLAN towards
the CPU port).

Fixes: 99b8202b179f ("net: dsa: fix SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING getting ignored")
Reported-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Tobias Waldekranz <tobias@waldekranz.com>
Tested-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 11 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 2eeaa42f2e08..9d4b0e9b1aa1 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -230,8 +230,8 @@ int dsa_port_hsr_join(struct dsa_port *dp, struct net_device *hsr);
 void dsa_port_hsr_leave(struct dsa_port *dp, struct net_device *hsr);
 extern const struct phylink_mac_ops dsa_port_phylink_mac_ops;
 
-static inline bool dsa_port_offloads_netdev(struct dsa_port *dp,
-					    struct net_device *dev)
+static inline bool dsa_port_offloads_bridge_port(struct dsa_port *dp,
+						 struct net_device *dev)
 {
 	/* Switchdev offloading can be configured on: */
 
@@ -241,12 +241,6 @@ static inline bool dsa_port_offloads_netdev(struct dsa_port *dp,
 		 */
 		return true;
 
-	if (dp->bridge_dev == dev)
-		/* DSA ports connected to a bridge, and event was emitted
-		 * for the bridge.
-		 */
-		return true;
-
 	if (dp->lag_dev == dev)
 		/* DSA ports connected to a bridge via a LAG */
 		return true;
@@ -254,14 +248,23 @@ static inline bool dsa_port_offloads_netdev(struct dsa_port *dp,
 	return false;
 }
 
+static inline bool dsa_port_offloads_bridge(struct dsa_port *dp,
+					    struct net_device *bridge_dev)
+{
+	/* DSA ports connected to a bridge, and event was emitted
+	 * for the bridge.
+	 */
+	return dp->bridge_dev == bridge_dev;
+}
+
 /* Returns true if any port of this tree offloads the given net_device */
-static inline bool dsa_tree_offloads_netdev(struct dsa_switch_tree *dst,
-					    struct net_device *dev)
+static inline bool dsa_tree_offloads_bridge_port(struct dsa_switch_tree *dst,
+						 struct net_device *dev)
 {
 	struct dsa_port *dp;
 
 	list_for_each_entry(dp, &dst->ports, list)
-		if (dsa_port_offloads_netdev(dp, dev))
+		if (dsa_port_offloads_bridge_port(dp, dev))
 			return true;
 
 	return false;