[PATCH v4 net-next 1/3] net: dsa: track whetever bridges have foreign interfaces in them

[Mattias Forsblad <mattias.forsblad@gmail.com>]

Track if a bridge stack has any foreign interfaces in them.

This patch is based on work done by Vlodimir Oltean.

Signed-off-by: Mattias Forsblad <mattias.forsblad@gmail.com>
---
 include/net/dsa.h  |  1 +
 net/dsa/dsa_priv.h |  1 +
 net/dsa/slave.c    | 88 +++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 81 insertions(+), 9 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 934958fda962..52b6da7d45b3 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -242,6 +242,7 @@ struct dsa_bridge {
 	unsigned int num;
 	bool tx_fwd_offload;
 	refcount_t refcount;
+	u8 have_foreign:1;
 };
 
 struct dsa_port {
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 5d3f4a67dce1..d610776ecd76 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -320,6 +320,7 @@ void dsa_slave_setup_tagger(struct net_device *slave);
 int dsa_slave_change_mtu(struct net_device *dev, int new_mtu);
 int dsa_slave_manage_vlan_filtering(struct net_device *dev,
 				    bool vlan_filtering);
+int dsa_bridge_foreign_dev_update(struct net_device *bridge_dev);
 
 static inline struct dsa_port *dsa_slave_to_port(const struct net_device *dev)
 {
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 41c69a6e7854..feaf64564c6e 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -2485,6 +2485,9 @@ static int dsa_slave_changeupper(struct net_device *dev,
 	struct netlink_ext_ack *extack;
 	int err = NOTIFY_DONE;
 
+	if (!dsa_slave_dev_check(dev))
+		return err;
+
 	extack = netdev_notifier_info_to_extack(&info->info);
 
 	if (netif_is_bridge_master(info->upper_dev)) {
@@ -2539,6 +2542,9 @@ static int dsa_slave_prechangeupper(struct net_device *dev,
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 
+	if (!dsa_slave_dev_check(dev))
+		return NOTIFY_DONE;
+
 	if (netif_is_bridge_master(info->upper_dev) && !info->linking)
 		dsa_port_pre_bridge_leave(dp, info->upper_dev);
 	else if (netif_is_lag_master(info->upper_dev) && !info->linking)
@@ -2559,6 +2565,9 @@ dsa_slave_lag_changeupper(struct net_device *dev,
 	int err = NOTIFY_DONE;
 	struct dsa_port *dp;
 
+	if (!netif_is_lag_master(dev))
+		return err;
+
 	netdev_for_each_lower_dev(dev, lower, iter) {
 		if (!dsa_slave_dev_check(lower))
 			continue;
@@ -2588,6 +2597,9 @@ dsa_slave_lag_prechangeupper(struct net_device *dev,
 	int err = NOTIFY_DONE;
 	struct dsa_port *dp;
 
+	if (!netif_is_lag_master(dev))
+		return err;
+
 	netdev_for_each_lower_dev(dev, lower, iter) {
 		if (!dsa_slave_dev_check(lower))
 			continue;
@@ -2605,6 +2617,18 @@ dsa_slave_lag_prechangeupper(struct net_device *dev,
 	return err;
 }
 
+static int dsa_bridge_changelower(struct net_device *dev,
+				  struct netdev_notifier_changeupper_info *info)
+{
+	int err;
+
+	if (!netif_is_bridge_master(info->upper_dev))
+		return NOTIFY_DONE;
+
+	err = dsa_bridge_foreign_dev_update(info->upper_dev);
+	return notifier_from_errno(err);
+}
+
 static int
 dsa_prevent_bridging_8021q_upper(struct net_device *dev,
 				 struct netdev_notifier_changeupper_info *info)
@@ -2709,22 +2733,33 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 		if (err != NOTIFY_DONE)
 			return err;
 
-		if (dsa_slave_dev_check(dev))
-			return dsa_slave_prechangeupper(dev, ptr);
+		err = dsa_slave_prechangeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
-		if (netif_is_lag_master(dev))
-			return dsa_slave_lag_prechangeupper(dev, ptr);
+		err = dsa_slave_lag_prechangeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
 		break;
 	}
-	case NETDEV_CHANGEUPPER:
-		if (dsa_slave_dev_check(dev))
-			return dsa_slave_changeupper(dev, ptr);
+	case NETDEV_CHANGEUPPER: {
+		int err;
 
-		if (netif_is_lag_master(dev))
-			return dsa_slave_lag_changeupper(dev, ptr);
+		err = dsa_slave_changeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_slave_lag_changeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_bridge_changelower(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
 		break;
+	}
 	case NETDEV_CHANGELOWERSTATE: {
 		struct netdev_notifier_changelowerstate_info *info = ptr;
 		struct dsa_port *dp;
@@ -2877,6 +2912,41 @@ static bool dsa_foreign_dev_check(const struct net_device *dev,
 	return true;
 }
 
+int dsa_bridge_foreign_dev_update(struct net_device *bridge_dev)
+{
+	struct net_device *first_slave, *lower;
+	struct dsa_bridge *bridge = NULL;
+	struct dsa_switch_tree *dst;
+	bool have_foreign = false;
+	struct list_head *iter;
+	struct dsa_port *dp;
+
+	list_for_each_entry(dst, &dsa_tree_list, list) {
+		dsa_tree_for_each_user_port(dp, dst) {
+			if (dsa_port_offloads_bridge_dev(dp, bridge_dev)) {
+				bridge = dp->bridge;
+				first_slave = dp->slave;
+				break;
+			}
+		}
+	}
+
+	/* Bridge with no DSA interface in it */
+	if (!bridge)
+		return 0;
+
+	netdev_for_each_lower_dev(bridge_dev, lower, iter) {
+		if (dsa_foreign_dev_check(first_slave, lower)) {
+			have_foreign = true;
+			break;
+		}
+	}
+
+	bridge->have_foreign = have_foreign;
+
+	return 0;
+}
+
 static int dsa_slave_fdb_event(struct net_device *dev,
 			       struct net_device *orig_dev,
 			       unsigned long event, const void *ctx,
-- 
2.25.1