net: bridge: ignore switchdev events for LAG ports which didn't request replay

There is a slight inconvenience in the switchdev replay helpers added
recently, and this is when:

ip link add br0 type bridge
ip link add bond0 type bond
ip link set bond0 master br0
bridge vlan add dev bond0 vid 100
ip link set swp0 master bond0
ip link set swp1 master bond0

Since the underlying driver (currently only DSA) asks for a replay of
VLANs when swp0 and swp1 join the LAG because it is bridged, what will
happen is that DSA will try to react twice on the VLAN event for swp0.
This is not really a huge problem right now, because most drivers accept
duplicates since the bridge itself does, but it will become a problem
when we add support for replaying switchdev object deletions.

Let's fix this by adding a blank void *ctx in the replay helpers, which
will be passed on by the bridge in the switchdev notifications. If the
context is NULL, everything is the same as before. But if the context is
populated with a valid pointer, the underlying switchdev driver
(currently DSA) can use the pointer to 'see through' the bridge port
(which in the example above is bond0) and 'know' that the event is only
for a particular physical port offloading that bridge port, and not for
all of them.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 3 deletions

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index b8d3ddfe5853..9d164a518e38 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -728,7 +728,7 @@ static inline size_t fdb_nlmsg_size(void)
 
 static int br_fdb_replay_one(struct notifier_block *nb,
 			     struct net_bridge_fdb_entry *fdb,
-			     struct net_device *dev)
+			     struct net_device *dev, const void *ctx)
 {
 	struct switchdev_notifier_fdb_info item;
 	int err;
@@ -739,13 +739,14 @@ static int br_fdb_replay_one(struct notifier_block *nb,
 	item.offloaded = test_bit(BR_FDB_OFFLOADED, &fdb->flags);
 	item.is_local = test_bit(BR_FDB_LOCAL, &fdb->flags);
 	item.info.dev = dev;
+	item.info.ctx = ctx;
 
 	err = nb->notifier_call(nb, SWITCHDEV_FDB_ADD_TO_DEVICE, &item);
 	return notifier_to_errno(err);
 }
 
 int br_fdb_replay(struct net_device *br_dev, struct net_device *dev,
-		  struct notifier_block *nb)
+		  const void *ctx, struct notifier_block *nb)
 {
 	struct net_bridge_fdb_entry *fdb;
 	struct net_bridge *br;
@@ -766,7 +767,7 @@ int br_fdb_replay(struct net_device *br_dev, struct net_device *dev,
 		if (dst_dev != br_dev && dst_dev != dev)
 			continue;
 
-		err = br_fdb_replay_one(nb, fdb, dst_dev);
+		err = br_fdb_replay_one(nb, fdb, dst_dev, ctx);
 		if (err)
 			break;
 	}