ipvlan: play well with macvlan device

Mahesh Bandewar · davem330 · commit 764e433b3c43 · 2014-12-09T16:10:06.000-05:00
If a device is already a macvlan port then refuse to use it as
an ipvlan port in the early stage of port creation.

	thost1:~# ip link add link eth0 mvl0 type macvlan
	thost1:~# echo $?
	0
	thost1:~# ip link add link eth0 ipvl0 type ipvlan
	RTNETLINK answers: Device or resource busy
	thost1:~# echo $?
	2
	thost1:~#

Signed-off-by: Mahesh Bandewar &lt;maheshb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
@@ -38,6 +38,12 @@ static int ipvlan_port_create(struct net_device *dev)
 		netdev_err(dev, "Master is either lo or non-ether device\n");
 		return -EINVAL;
 	}
+
+	if (netif_is_macvlan_port(dev)) {
+		netdev_err(dev, "Master is a macvlan port.\n");
+		return -EBUSY;
+	}
+
 	port = kzalloc(sizeof(struct ipvl_port), GFP_KERNEL);
 	if (!port)
 		return -ENOMEM;
