net: disallow drivers with buggy VLAN accel to register_netdevice()

Instead of jumping aroung bugs that are easily fixed just don't let them in:
affected drivers should be either fixed or have NETIF_F_HW_VLAN_FILTER
removed from advertised features.

Quick grep in drivers/net shows two drivers that have NETIF_F_HW_VLAN_FILTER
but not ndo_vlan_rx_add/kill_vid(), but those are false-positives (features
are commented out).

OTOH two drivers have ndo_vlan_rx_add/kill_vid() implemented but don't
advertise NETIF_F_HW_VLAN_FILTER. Those are:

+ethernet/cisco/enic/enic_main.c
+ethernet/qlogic/qlcnic/qlcnic_main.c
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/8021q/vlan.c

@@ -117,19 +117,12 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
 int vlan_check_real_dev(struct net_device *real_dev, u16 vlan_id)
 {
 	const char *name = real_dev->name;
-	const struct net_device_ops *ops = real_dev->netdev_ops;
 
 	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
 		pr_info("VLANs not supported on %s\n", name);
 		return -EOPNOTSUPP;
 	}
 
-	if ((real_dev->features & NETIF_F_HW_VLAN_FILTER) &&
-	    (!ops->ndo_vlan_rx_add_vid || !ops->ndo_vlan_rx_kill_vid)) {
-		pr_info("Device %s has buggy VLAN hw accel\n", name);
-		return -EOPNOTSUPP;
-	}
-
 	if (vlan_find_dev(real_dev, vlan_id) != NULL)
 		return -EEXIST;
 

net/8021q/vlan_core.c

@@ -224,8 +224,7 @@ static int __vlan_vid_add(struct vlan_info *vlan_info, unsigned short vid,
 	if (!vid_info)
 		return -ENOMEM;
 
-	if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
-	    ops->ndo_vlan_rx_add_vid) {
+	if (dev->features & NETIF_F_HW_VLAN_FILTER) {
 		err =  ops->ndo_vlan_rx_add_vid(dev, vid);
 		if (err) {
 			kfree(vid_info);
@@ -282,8 +281,7 @@ static void __vlan_vid_del(struct vlan_info *vlan_info,
 	unsigned short vid = vid_info->vid;
 	int err;
 
-	if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
-	     ops->ndo_vlan_rx_kill_vid) {
+	if (dev->features & NETIF_F_HW_VLAN_FILTER) {
 		err = ops->ndo_vlan_rx_kill_vid(dev, vid);
 		if (err) {
 			pr_warn("failed to kill vid %d for device %s\n",

net/core/dev.c

@@ -6054,6 +6054,14 @@ int register_netdevice(struct net_device *dev)
 		}
 	}
 
+	if (((dev->hw_features | dev->features) & NETIF_F_HW_VLAN_FILTER) &&
+	    (!dev->netdev_ops->ndo_vlan_rx_add_vid ||
+	     !dev->netdev_ops->ndo_vlan_rx_kill_vid)) {
+		netdev_WARN(dev, "Buggy VLAN acceleration in driver!\n");
+		ret = -EINVAL;
+		goto err_uninit;
+	}
+
 	ret = -EBUSY;
 	if (!dev->ifindex)
 		dev->ifindex = dev_new_index(net);