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>

4 files changed, 85 insertions, 88 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 619cd081339e..66de492117ad 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1143,6 +1143,7 @@ static int mv88e6xxx_pri_setup(struct mv88e6xxx_chip *chip)
 
 static int mv88e6xxx_devmap_setup(struct mv88e6xxx_chip *chip)
 {
+	struct dsa_switch *ds = chip->ds;
 	int target, port;
 	int err;
 
@@ -1151,10 +1152,9 @@ static int mv88e6xxx_devmap_setup(struct mv88e6xxx_chip *chip)
 
 	/* Initialize the routing port to the 32 possible target devices */
 	for (target = 0; target < 32; target++) {
-		port = 0x1f;
-		if (target < DSA_MAX_SWITCHES)
-			if (chip->ds->rtable[target] != DSA_RTABLE_NONE)
-				port = chip->ds->rtable[target];
+		port = dsa_routing_port(ds, target);
+		if (port == ds->num_ports)
+			port = 0x1f;
 
 		err = mv88e6xxx_g2_device_mapping_write(chip, target, port);
 		if (err)
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 */
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index e7aae96b54bb..ff2fa3950c62 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -45,6 +45,8 @@ static struct dsa_switch_tree *dsa_tree_alloc(int index)
 
 	dst->index = index;
 
+	INIT_LIST_HEAD(&dst->rtable);
+
 	INIT_LIST_HEAD(&dst->ports);
 
 	INIT_LIST_HEAD(&dst->list);
@@ -122,6 +124,31 @@ static struct dsa_port *dsa_tree_find_port_by_node(struct dsa_switch_tree *dst,
 	return NULL;
 }
 
+struct dsa_link *dsa_link_touch(struct dsa_port *dp, struct dsa_port *link_dp)
+{
+	struct dsa_switch *ds = dp->ds;
+	struct dsa_switch_tree *dst;
+	struct dsa_link *dl;
+
+	dst = ds->dst;
+
+	list_for_each_entry(dl, &dst->rtable, list)
+		if (dl->dp == dp && dl->link_dp == link_dp)
+			return dl;
+
+	dl = kzalloc(sizeof(*dl), GFP_KERNEL);
+	if (!dl)
+		return NULL;
+
+	dl->dp = dp;
+	dl->link_dp = link_dp;
+
+	INIT_LIST_HEAD(&dl->list);
+	list_add_tail(&dl->list, &dst->rtable);
+
+	return dl;
+}
+
 static bool dsa_port_setup_routing_table(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
@@ -129,6 +156,7 @@ static bool dsa_port_setup_routing_table(struct dsa_port *dp)
 	struct device_node *dn = dp->dn;
 	struct of_phandle_iterator it;
 	struct dsa_port *link_dp;
+	struct dsa_link *dl;
 	int err;
 
 	of_for_each_phandle(&it, err, dn, "link", NULL, 0) {
@@ -138,24 +166,23 @@ static bool dsa_port_setup_routing_table(struct dsa_port *dp)
 			return false;
 		}
 
-		ds->rtable[link_dp->ds->index] = dp->index;
+		dl = dsa_link_touch(dp, link_dp);
+		if (!dl) {
+			of_node_put(it.node);
+			return false;
+		}
 	}
 
 	return true;
 }
 
-static bool dsa_switch_setup_routing_table(struct dsa_switch *ds)
+static bool dsa_tree_setup_routing_table(struct dsa_switch_tree *dst)
 {
-	struct dsa_switch_tree *dst = ds->dst;
 	bool complete = true;
 	struct dsa_port *dp;
-	int i;
-
-	for (i = 0; i < DSA_MAX_SWITCHES; i++)
-		ds->rtable[i] = DSA_RTABLE_NONE;
 
 	list_for_each_entry(dp, &dst->ports, list) {
-		if (dp->ds == ds && dsa_port_is_dsa(dp)) {
+		if (dsa_port_is_dsa(dp)) {
 			complete = dsa_port_setup_routing_table(dp);
 			if (!complete)
 				break;
@@ -165,25 +192,6 @@ static bool dsa_switch_setup_routing_table(struct dsa_switch *ds)
 	return complete;
 }
 
-static bool dsa_tree_setup_routing_table(struct dsa_switch_tree *dst)
-{
-	struct dsa_switch *ds;
-	bool complete = true;
-	int device;
-
-	for (device = 0; device < DSA_MAX_SWITCHES; device++) {
-		ds = dst->ds[device];
-		if (!ds)
-			continue;
-
-		complete = dsa_switch_setup_routing_table(ds);
-		if (!complete)
-			break;
-	}
-
-	return complete;
-}
-
 static struct dsa_port *dsa_tree_find_first_cpu(struct dsa_switch_tree *dst)
 {
 	struct dsa_port *dp;
@@ -544,6 +552,8 @@ teardown_default_cpu:
 
 static void dsa_tree_teardown(struct dsa_switch_tree *dst)
 {
+	struct dsa_link *dl, *next;
+
 	if (!dst->setup)
 		return;
 
@@ -553,41 +563,16 @@ static void dsa_tree_teardown(struct dsa_switch_tree *dst)
 
 	dsa_tree_teardown_default_cpu(dst);
 
+	list_for_each_entry_safe(dl, next, &dst->rtable, list) {
+		list_del(&dl->list);
+		kfree(dl);
+	}
+
 	pr_info("DSA: tree %d torn down\n", dst->index);
 
 	dst->setup = false;
 }
 
-static void dsa_tree_remove_switch(struct dsa_switch_tree *dst,
-				   unsigned int index)
-{
-	dsa_tree_teardown(dst);
-
-	dst->ds[index] = NULL;
-	dsa_tree_put(dst);
-}
-
-static int dsa_tree_add_switch(struct dsa_switch_tree *dst,
-			       struct dsa_switch *ds)
-{
-	unsigned int index = ds->index;
-	int err;
-
-	if (dst->ds[index])
-		return -EBUSY;
-
-	dsa_tree_get(dst);
-	dst->ds[index] = ds;
-
-	err = dsa_tree_setup(dst);
-	if (err) {
-		dst->ds[index] = NULL;
-		dsa_tree_put(dst);
-	}
-
-	return err;
-}
-
 static struct dsa_port *dsa_port_touch(struct dsa_switch *ds, int index)
 {
 	struct dsa_switch_tree *dst = ds->dst;
@@ -726,8 +711,6 @@ static int dsa_switch_parse_member_of(struct dsa_switch *ds,
 		return sz;
 
 	ds->index = m[1];
-	if (ds->index >= DSA_MAX_SWITCHES)
-		return -EINVAL;
 
 	ds->dst = dsa_tree_touch(m[0]);
 	if (!ds->dst)
@@ -838,15 +821,9 @@ static int dsa_switch_parse(struct dsa_switch *ds, struct dsa_chip_data *cd)
 	return dsa_switch_parse_ports(ds, cd);
 }
 
-static int dsa_switch_add(struct dsa_switch *ds)
-{
-	struct dsa_switch_tree *dst = ds->dst;
-
-	return dsa_tree_add_switch(dst, ds);
-}
-
 static int dsa_switch_probe(struct dsa_switch *ds)
 {
+	struct dsa_switch_tree *dst;
 	struct dsa_chip_data *pdata;
 	struct device_node *np;
 	int err;
@@ -870,7 +847,13 @@ static int dsa_switch_probe(struct dsa_switch *ds)
 	if (err)
 		return err;
 
-	return dsa_switch_add(ds);
+	dst = ds->dst;
+	dsa_tree_get(dst);
+	err = dsa_tree_setup(dst);
+	if (err)
+		dsa_tree_put(dst);
+
+	return err;
 }
 
 int dsa_register_switch(struct dsa_switch *ds)
@@ -889,7 +872,6 @@ EXPORT_SYMBOL_GPL(dsa_register_switch);
 static void dsa_switch_remove(struct dsa_switch *ds)
 {
 	struct dsa_switch_tree *dst = ds->dst;
-	unsigned int index = ds->index;
 	struct dsa_port *dp, *next;
 
 	list_for_each_entry_safe(dp, next, &dst->ports, list) {
@@ -897,7 +879,8 @@ static void dsa_switch_remove(struct dsa_switch *ds)
 		kfree(dp);
 	}
 
-	dsa_tree_remove_switch(dst, index);
+	dsa_tree_teardown(dst);
+	dsa_tree_put(dst);
 }
 
 void dsa_unregister_switch(struct dsa_switch *ds)
diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index bf91fc55fc44..bc5cb91bf052 100644
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -31,15 +31,14 @@
  *	Must be transmitted as zero and ignored on receive.
  *
  * SWITCH_ID - VID[8:6]:
- *	Index of switch within DSA tree. Must be between 0 and
- *	DSA_MAX_SWITCHES - 1.
+ *	Index of switch within DSA tree. Must be between 0 and 7.
  *
  * RSV - VID[5:4]:
  *	To be used for further expansion of PORT or for other purposes.
  *	Must be transmitted as zero and ignored on receive.
  *
  * PORT - VID[3:0]:
- *	Index of switch port. Must be between 0 and DSA_MAX_PORTS - 1.
+ *	Index of switch port. Must be between 0 and 15.
  */
 
 #define DSA_8021Q_DIR_SHIFT		10