net: dsa: tag_8021q: Change order of rx_vid setup

The 802.1Q tagging performs an unbalanced setup in terms of RX VIDs on
the CPU port. For the ingress path of a 802.1Q switch to work, the RX
VID of a port needs to be seen as tagged egress on the CPU port.

While configuring the other front-panel ports to be part of this VID,
for bridge scenarios, the untagged flag is applied even on the CPU port
in dsa_switch_vlan_add.  This happens because DSA applies the same flags
on the CPU port as on the (bridge-controlled) slave ports, and the
effect in this case is that the CPU port tagged settings get deleted.

Instead of fixing DSA by introducing a way to control VLAN flags on the
CPU port (and hence stop inheriting from the slave ports) - a hard,
perhaps intractable problem - avoid this situation by moving the setup
part of the RX VID on the CPU port after all the other front-panel ports
have been added to the VID.

Fixes: f9bbe4477c30 ("net: dsa: Optional VLAN-based port separation for switches without tagging")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index 8ae48c7..4adec6b 100644 (file)
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -128,10 +128,7 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
                u16 flags;
 
                if (i == upstream)
-                       /* CPU port needs to see this port's RX VID
-                        * as tagged egress.
-                        */
-                       flags = 0;
+                       continue;
                else if (i == port)
                        /* The RX VID is pvid on this port */
                        flags = BRIDGE_VLAN_INFO_UNTAGGED |
@@ -150,6 +147,20 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
                        return err;
                }
        }
+
+       /* CPU port needs to see this port's RX VID
+        * as tagged egress.
+        */
+       if (enabled)
+               err = dsa_port_vid_add(upstream_dp, rx_vid, 0);
+       else
+               err = dsa_port_vid_del(upstream_dp, rx_vid);
+       if (err) {
+               dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n",
+                       rx_vid, port, err);
+               return err;
+       }
+
        /* Finally apply the TX VID on this port and on the CPU port */
        if (enabled)
                err = dsa_port_vid_add(dp, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED);