driver: macvlan: Destroy new macvlan port if macvlan_common_newlink failed.

When there is no existing macvlan port in lowdev, one new macvlan port
would be created. But it doesn't be destoried when something failed later.
It casues some memleak.

Now add one flag to indicate if new macvlan port is created.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -1278,6 +1278,7 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 	struct net_device *lowerdev;
 	int err;
 	int macmode;
+	bool create = false;
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
@@ -1304,12 +1305,18 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 		err = macvlan_port_create(lowerdev);
 		if (err < 0)
 			return err;
+		create = true;
 	}
 	port = macvlan_port_get_rtnl(lowerdev);
 
 	/* Only 1 macvlan device can be created in passthru mode */
-	if (port->passthru)
-		return -EINVAL;
+	if (port->passthru) {
+		/* The macvlan port must be not created this time,
+		 * still goto destroy_macvlan_port for readability.
+		 */
+		err = -EINVAL;
+		goto destroy_macvlan_port;
+	}
 
 	vlan->lowerdev = lowerdev;
 	vlan->dev      = dev;
@@ -1325,24 +1332,28 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 		vlan->flags = nla_get_u16(data[IFLA_MACVLAN_FLAGS]);
 
 	if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
-		if (port->count)
-			return -EINVAL;
+		if (port->count) {
+			err = -EINVAL;
+			goto destroy_macvlan_port;
+		}
 		port->passthru = true;
 		eth_hw_addr_inherit(dev, lowerdev);
 	}
 
 	if (data && data[IFLA_MACVLAN_MACADDR_MODE]) {
-		if (vlan->mode != MACVLAN_MODE_SOURCE)
-			return -EINVAL;
+		if (vlan->mode != MACVLAN_MODE_SOURCE) {
+			err = -EINVAL;
+			goto destroy_macvlan_port;
+		}
 		macmode = nla_get_u32(data[IFLA_MACVLAN_MACADDR_MODE]);
 		err = macvlan_changelink_sources(vlan, macmode, data);
 		if (err)
-			return err;
+			goto destroy_macvlan_port;
 	}
 
 	err = register_netdevice(dev);
 	if (err < 0)
-		return err;
+		goto destroy_macvlan_port;
 
 	dev->priv_flags |= IFF_MACVLAN;
 	err = netdev_upper_dev_link(lowerdev, dev);
@@ -1357,7 +1368,9 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 
 unregister_netdev:
 	unregister_netdevice(dev);
-
+destroy_macvlan_port:
+	if (create)
+		macvlan_port_destroy(port->dev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(macvlan_common_newlink);