4 files changed, 25 insertions, 7 deletions
diff --git a/net/bridge/br.c b/net/bridge/br.c
index 7770481a6506..a3f95ab9d6a3 100644
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -52,7 +52,7 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 
 	switch (event) {
 	case NETDEV_CHANGEMTU:
-		dev_set_mtu(br->dev, br_min_mtu(br));
+		dev_set_mtu(br->dev, br_mtu(br));
 		break;
 
 	case NETDEV_CHANGEADDR:
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 1285ca30ab0a..278fc999d355 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -224,7 +224,7 @@ static void br_get_stats64(struct net_device *dev,
 static int br_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct net_bridge *br = netdev_priv(dev);
-	if (new_mtu > br_min_mtu(br))
+	if (new_mtu > br_mtu(br))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 9ba4ed65c52b..48dc4d2e2be3 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -424,8 +424,18 @@ int br_del_bridge(struct net *net, const char *name)
 	return ret;
 }
 
+static bool min_mtu(int a, int b)
+{
+	return a < b ? 1 : 0;
+}
+
+static bool max_mtu(int a, int b)
+{
+	return a > b ? 1 : 0;
+}
+
 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
-int br_min_mtu(const struct net_bridge *br)
+static int __br_mtu(const struct net_bridge *br, bool (compare_fn)(int, int))
 {
 	const struct net_bridge_port *p;
 	int mtu = 0;
@@ -436,13 +446,21 @@ int br_min_mtu(const struct net_bridge *br)
 		mtu = ETH_DATA_LEN;
 	else {
 		list_for_each_entry(p, &br->port_list, list) {
-			if (!mtu  || p->dev->mtu < mtu)
+			if (!mtu || compare_fn(p->dev->mtu, mtu))
 				mtu = p->dev->mtu;
 		}
 	}
 	return mtu;
 }
 
+int br_mtu(const struct net_bridge *br)
+{
+	if (br->vlan_enabled)
+		return __br_mtu(br, max_mtu);
+	else
+		return __br_mtu(br, min_mtu);
+}
+
 static void br_set_gso_limits(struct net_bridge *br)
 {
 	unsigned int gso_max_size = GSO_MAX_SIZE;
@@ -594,7 +612,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
 	if (changed_addr)
 		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 
-	dev_set_mtu(br->dev, br_min_mtu(br));
+	dev_set_mtu(br->dev, br_mtu(br));
 	br_set_gso_limits(br);
 
 	kobject_uevent(&p->kobj, KOBJ_ADD);
@@ -641,7 +659,7 @@ int br_del_if(struct net_bridge *br, struct net_device *dev)
 	 */
 	del_nbp(p);
 
-	dev_set_mtu(br->dev, br_min_mtu(br));
+	dev_set_mtu(br->dev, br_mtu(br));
 	br_set_gso_limits(br);
 
 	spin_lock_bh(&br->lock);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 8e13a64d8c99..048d5b51813b 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -578,7 +578,7 @@ int br_del_bridge(struct net *net, const char *name);
 int br_add_if(struct net_bridge *br, struct net_device *dev,
 	      struct netlink_ext_ack *extack);
 int br_del_if(struct net_bridge *br, struct net_device *dev);
-int br_min_mtu(const struct net_bridge *br);
+int br_mtu(const struct net_bridge *br);
 netdev_features_t br_features_recompute(struct net_bridge *br,
 					netdev_features_t features);
 void br_port_flags_change(struct net_bridge_port *port, unsigned long mask);