net: dsa: mv88e6xxx: share the same default FDB

For hardware cross-chip bridging to work, user ports *and* DSA ports
need to share a common address database, in order to switch a frame to
the correct interconnected device.

This is currently working for VLAN filtering aware systems, since Linux
will implement a bridge group as a 802.1Q VLAN, which has its own FDB,
including DSA and CPU links as members.

However when the system doesn't support VLAN filtering, Linux only
relies on the port-based VLAN to implement a bridge group.

To fix hardware cross-chip bridging for such systems, set the same
default address database 0 for user and DSA ports, instead of giving
them all a different default database.

Note that the bridging code prevents frames to egress between unbridged
ports, and flushes FDB entries of a port when changing its STP state.

Also note that the FID 0 is special and means "all" for ATU operations,
but it's OK since it is used as a default forwarding address database.

Fixes: 2db9ce1fd9a3 ("net: dsa: mv88e6xxx: assign default FDB to ports")
Fixes: 466dfa077022 ("net: dsa: mv88e6xxx: assign dynamic FDB to bridges")
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 169c948..a290402 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -2181,27 +2181,10 @@ int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
                               struct net_device *bridge)
 {
        struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
-       u16 fid;
        int i, err;
 
        mutex_lock(&ps->smi_mutex);
 
-       /* Get or create the bridge FID and assign it to the port */
-       for (i = 0; i < ps->num_ports; ++i)
-               if (ps->ports[i].bridge_dev == bridge)
-                       break;
-
-       if (i < ps->num_ports)
-               err = _mv88e6xxx_port_fid_get(ds, i, &fid);
-       else
-               err = _mv88e6xxx_fid_new(ds, &fid);
-       if (err)
-               goto unlock;
-
-       err = _mv88e6xxx_port_fid_set(ds, port, fid);
-       if (err)
-               goto unlock;
-
        /* Assign the bridge and remap each port's VLANTable */
        ps->ports[port].bridge_dev = bridge;
 
@@ -2213,7 +2196,6 @@ int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
                }
        }
 
-unlock:
        mutex_unlock(&ps->smi_mutex);
 
        return err;
@@ -2223,16 +2205,10 @@ void mv88e6xxx_port_bridge_leave(struct dsa_switch *ds, int port)
 {
        struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
        struct net_device *bridge = ps->ports[port].bridge_dev;
-       u16 fid;
        int i;
 
        mutex_lock(&ps->smi_mutex);
 
-       /* Give the port a fresh Filtering Information Database */
-       if (_mv88e6xxx_fid_new(ds, &fid) ||
-           _mv88e6xxx_port_fid_set(ds, port, fid))
-               netdev_warn(ds->ports[port], "failed to assign a new FID\n");
-
        /* Unassign the bridge and remap each port's VLANTable */
        ps->ports[port].bridge_dev = NULL;
 
@@ -2558,11 +2534,11 @@ static int mv88e6xxx_setup_port(struct dsa_switch *ds, int port)
        if (ret)
                goto abort;
 
-       /* Port based VLAN map: give each port its own address
+       /* Port based VLAN map: give each port the same default address
         * database, and allow bidirectional communication between the
         * CPU and DSA port(s), and the other ports.
         */
-       ret = _mv88e6xxx_port_fid_set(ds, port, port + 1);
+       ret = _mv88e6xxx_port_fid_set(ds, port, 0);
        if (ret)
                goto abort;