ipvlan: play well with macvlan device

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 <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index feb185389a87ed03cf24449dcf3b3121d72e5108..a66ff81970087b852d3c275d97a90826182ab866 100644 (file)
--- 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;