net: dsa: Handle MST state changes

Add the usual trampoline functionality from the generic DSA layer down
to the drivers for MST state changes.

When a state changes to disabled/blocking/listening, make sure to fast
age any dynamic entries in the affected VLANs (those controlled by the
MSTI in question).
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/dsa.h

@@ -957,7 +957,10 @@ struct dsa_switch_ops {
 				     struct dsa_bridge bridge);
 	void	(*port_stp_state_set)(struct dsa_switch *ds, int port,
 				      u8 state);
+	int	(*port_mst_state_set)(struct dsa_switch *ds, int port,
+				      const struct switchdev_mst_state *state);
 	void	(*port_fast_age)(struct dsa_switch *ds, int port);
+	int	(*port_vlan_fast_age)(struct dsa_switch *ds, int port, u16 vid);
 	int	(*port_pre_bridge_flags)(struct dsa_switch *ds, int port,
 					 struct switchdev_brport_flags flags,
 					 struct netlink_ext_ack *extack);

net/dsa/dsa_priv.h

@@ -215,6 +215,9 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops);
 int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state,
+			   struct netlink_ext_ack *extack);
 int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy);
 int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy);
 void dsa_port_disable_rt(struct dsa_port *dp);

net/dsa/port.c

@@ -30,12 +30,11 @@ static int dsa_port_notify(const struct dsa_port *dp, unsigned long e, void *v)
 	return dsa_tree_notify(dp->ds->dst, e, v);
 }
 
-static void dsa_port_notify_bridge_fdb_flush(const struct dsa_port *dp)
+static void dsa_port_notify_bridge_fdb_flush(const struct dsa_port *dp, u16 vid)
 {
 	struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
 	struct switchdev_notifier_fdb_info info = {
-		/* flush all VLANs */
-		.vid = 0,
+		.vid = vid,
 	};
 
 	/* When the port becomes standalone it has already left the bridge.
@@ -57,7 +56,42 @@ static void dsa_port_fast_age(const struct dsa_port *dp)
 
 	ds->ops->port_fast_age(ds, dp->index);
 
-	dsa_port_notify_bridge_fdb_flush(dp);
+	/* flush all VLANs */
+	dsa_port_notify_bridge_fdb_flush(dp, 0);
+}
+
+static int dsa_port_vlan_fast_age(const struct dsa_port *dp, u16 vid)
+{
+	struct dsa_switch *ds = dp->ds;
+	int err;
+
+	if (!ds->ops->port_vlan_fast_age)
+		return -EOPNOTSUPP;
+
+	err = ds->ops->port_vlan_fast_age(ds, dp->index, vid);
+
+	if (!err)
+		dsa_port_notify_bridge_fdb_flush(dp, vid);
+
+	return err;
+}
+
+static int dsa_port_msti_fast_age(const struct dsa_port *dp, u16 msti)
+{
+	DECLARE_BITMAP(vids, VLAN_N_VID) = { 0 };
+	int err, vid;
+
+	err = br_mst_get_info(dsa_port_bridge_dev_get(dp), msti, vids);
+	if (err)
+		return err;
+
+	for_each_set_bit(vid, vids, VLAN_N_VID) {
+		err = dsa_port_vlan_fast_age(dp, vid);
+		if (err)
+			return err;
+	}
+
+	return 0;
 }
 
 static bool dsa_port_can_configure_learning(struct dsa_port *dp)
@@ -118,6 +152,42 @@ static void dsa_port_set_state_now(struct dsa_port *dp, u8 state,
 		pr_err("DSA: failed to set STP state %u (%d)\n", state, err);
 }
 
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state,
+			   struct netlink_ext_ack *extack)
+{
+	struct dsa_switch *ds = dp->ds;
+	u8 prev_state;
+	int err;
+
+	if (!ds->ops->port_mst_state_set)
+		return -EOPNOTSUPP;
+
+	err = br_mst_get_state(dsa_port_to_bridge_port(dp), state->msti,
+			       &prev_state);
+	if (err)
+		return err;
+
+	err = ds->ops->port_mst_state_set(ds, dp->index, state);
+	if (err)
+		return err;
+
+	if (!(dp->learning &&
+	      (prev_state == BR_STATE_LEARNING ||
+	       prev_state == BR_STATE_FORWARDING) &&
+	      (state->state == BR_STATE_DISABLED ||
+	       state->state == BR_STATE_BLOCKING ||
+	       state->state == BR_STATE_LISTENING)))
+		return 0;
+
+	err = dsa_port_msti_fast_age(dp, state->msti);
+	if (err)
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Unable to flush associated VLANs");
+
+	return 0;
+}
+
 int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy)
 {
 	struct dsa_switch *ds = dp->ds;
@@ -326,6 +396,8 @@ static bool dsa_port_supports_mst(struct dsa_port *dp)
 	struct dsa_switch *ds = dp->ds;
 
 	return ds->ops->vlan_msti_set &&
+		ds->ops->port_mst_state_set &&
+		ds->ops->port_vlan_fast_age &&
 		dsa_port_can_configure_learning(dp);
 }
 
@@ -749,10 +821,7 @@ int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock)
 int dsa_port_mst_enable(struct dsa_port *dp, bool on,
 			struct netlink_ext_ack *extack)
 {
-	if (!on)
-		return 0;
-
-	if (!dsa_port_supports_mst(dp)) {
+	if (on && !dsa_port_supports_mst(dp)) {
 		NL_SET_ERR_MSG_MOD(extack, "Hardware does not support MST");
 		return -EINVAL;
 	}

net/dsa/slave.c

@@ -451,6 +451,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev, const void *ctx,
 
 		ret = dsa_port_set_state(dp, attr->u.stp_state, true);
 		break;
+	case SWITCHDEV_ATTR_ID_PORT_MST_STATE:
+		if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
+			return -EOPNOTSUPP;
+
+		ret = dsa_port_set_mst_state(dp, &attr->u.mst_state, extack);
+		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
 		if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
 			return -EOPNOTSUPP;