net: dsa: tag_sja1105: stop asking the sja1105 driver in sja1105_xmit_tpid

[mirror_ubuntu-jammy-kernel.git] / net / dsa / tag_sja1105.c

diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index a49308fbd19f4f0f03c70d1485e144626a4f1c0e..c054f48541c8d621ca018cb94016193789e66c37 100644 (file)
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -133,14 +133,44 @@ static struct sk_buff *sja1105_defer_xmit(struct dsa_port *dp,
        return NULL;
 }
 
+/* Send VLAN tags with a TPID that blends in with whatever VLAN protocol a
+ * bridge spanning ports of this switch might have.
+ */
 static u16 sja1105_xmit_tpid(struct dsa_port *dp)
 {
-       struct sja1105_port *sp = dp->priv;
+       struct dsa_switch *ds = dp->ds;
+       struct dsa_port *other_dp;
+       u16 proto;
+
+       /* Since VLAN awareness is global, then if this port is VLAN-unaware,
+        * all ports are. Use the VLAN-unaware TPID used for tag_8021q.
+        */
+       if (!dsa_port_is_vlan_filtering(dp))
+               return ETH_P_SJA1105;
+
+       /* Port is VLAN-aware, so there is a bridge somewhere (a single one,
+        * we're sure about that). It may not be on this port though, so we
+        * need to find it.
+        */
+       list_for_each_entry(other_dp, &ds->dst->ports, list) {
+               if (other_dp->ds != ds)
+                       continue;
+
+               if (!other_dp->bridge_dev)
+                       continue;
+
+               /* Error is returned only if CONFIG_BRIDGE_VLAN_FILTERING,
+                * which seems pointless to handle, as our port cannot become
+                * VLAN-aware in that case.
+                */
+               br_vlan_get_proto(other_dp->bridge_dev, &proto);
+
+               return proto;
+       }
 
-       if (unlikely(!dsa_port_is_sja1105(dp)))
-               return ETH_P_8021Q;
+       WARN_ONCE(1, "Port is VLAN-aware but cannot find associated bridge!\n");
 
-       return sp->xmit_tpid;
+       return ETH_P_SJA1105;
 }
 
 static struct sk_buff *sja1105_imprecise_xmit(struct sk_buff *skb,