net: dsa: resolve tagging protocol at parse time

Extend the dsa_port_parse_cpu() function to resolve the tagging protocol
at port parsing time, instead of waiting for the whole tree to be
complete.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 271a97e..283104e 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -511,22 +511,11 @@ static int dsa_port_parse_dsa(struct dsa_port *dp)
 
 static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
 {
-	dp->type = DSA_PORT_TYPE_CPU;
-	dp->master = master;
-
-	return 0;
-}
-
-static int dsa_cpu_parse(struct dsa_port *port, u32 index,
-			 struct dsa_switch_tree *dst,
-			 struct dsa_switch *ds)
-{
+	struct dsa_switch *ds = dp->ds;
+	struct dsa_switch_tree *dst = ds->dst;
 	const struct dsa_device_ops *tag_ops;
 	enum dsa_tag_protocol tag_protocol;
 
-	if (!dst->cpu_dp)
-		dst->cpu_dp = port;
-
 	tag_protocol = ds->ops->get_tag_protocol(ds);
 	tag_ops = dsa_resolve_tag_protocol(tag_protocol);
 	if (IS_ERR(tag_ops)) {
@@ -534,11 +523,21 @@ static int dsa_cpu_parse(struct dsa_port *port, u32 index,
 		return PTR_ERR(tag_ops);
 	}
 
-	dst->cpu_dp->tag_ops = tag_ops;
+	dp->type = DSA_PORT_TYPE_CPU;
+	dp->rcv = tag_ops->rcv;
+	dp->tag_ops = tag_ops;
+	dp->master = master;
+	dp->dst = dst;
 
-	/* Make a few copies for faster access in master receive hot path */
-	dst->cpu_dp->rcv = dst->cpu_dp->tag_ops->rcv;
-	dst->cpu_dp->dst = dst;
+	return 0;
+}
+
+static int dsa_cpu_parse(struct dsa_port *port, u32 index,
+			 struct dsa_switch_tree *dst,
+			 struct dsa_switch *ds)
+{
+	if (!dst->cpu_dp)
+		dst->cpu_dp = port;
 
 	return 0;
 }