Merge branch 'net-dsa-replace-routing-tables-with-a-list'

Vivien Didelot says:

====================
net: dsa: replace routing tables with a list

This branch gets rid of the ds->rtable static arrays in favor of
a single dst->rtable list. This allows us to move away from the
DSA_MAX_SWITCHES limitation and simplify the switch fabric setup.

Changes in v2:
  - fix the reverse christmas for David
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 12 deletions

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 9aba326abb64..e4c697b95c70 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -123,10 +123,8 @@ struct dsa_switch_tree {
 	/* List of switch ports */
 	struct list_head ports;
 
-	/*
-	 * Data for the individual switch chips.
-	 */
-	struct dsa_switch	*ds[DSA_MAX_SWITCHES];
+	/* List of DSA links composing the routing table */
+	struct list_head rtable;
 };
 
 /* TC matchall action types, only mirroring for now */
@@ -214,6 +212,17 @@ struct dsa_port {
 	bool setup;
 };
 
+/* TODO: ideally DSA ports would have a single dp->link_dp member,
+ * and no dst->rtable nor this struct dsa_link would be needed,
+ * but this would require some more complex tree walking,
+ * so keep it stupid at the moment and list them all.
+ */
+struct dsa_link {
+	struct dsa_port *dp;
+	struct dsa_port *link_dp;
+	struct list_head list;
+};
+
 struct dsa_switch {
 	bool setup;
 
@@ -245,13 +254,6 @@ struct dsa_switch {
 	const struct dsa_switch_ops	*ops;
 
 	/*
-	 * An array of which element [a] indicates which port on this
-	 * switch should be used to send packets to that are destined
-	 * for switch a. Can be NULL if there is only one switch chip.
-	 */
-	s8		rtable[DSA_MAX_SWITCHES];
-
-	/*
 	 * Slave mii_bus and devices for the individual ports.
 	 */
 	u32			phys_mii_mask;
@@ -324,6 +326,19 @@ static inline u32 dsa_user_ports(struct dsa_switch *ds)
 	return mask;
 }
 
+/* Return the local port used to reach an arbitrary switch device */
+static inline unsigned int dsa_routing_port(struct dsa_switch *ds, int device)
+{
+	struct dsa_switch_tree *dst = ds->dst;
+	struct dsa_link *dl;
+
+	list_for_each_entry(dl, &dst->rtable, list)
+		if (dl->dp->ds == ds && dl->link_dp->ds->index == device)
+			return dl->dp->index;
+
+	return ds->num_ports;
+}
+
 /* Return the local port used to reach an arbitrary switch port */
 static inline unsigned int dsa_towards_port(struct dsa_switch *ds, int device,
 					    int port)
@@ -331,7 +346,7 @@ static inline unsigned int dsa_towards_port(struct dsa_switch *ds, int device,
 	if (device == ds->index)
 		return port;
 	else
-		return ds->rtable[device];
+		return dsa_routing_port(ds, device);
 }
 
 /* Return the local port used to reach the dedicated CPU port */