Revert "net: maintain namespace isolation between vlan and real device"

This reverts commit 8a83a00b.

It causes regressions for S390 devices, because it does an
unconditional DST drop on SKBs for vlans and the QETH device
needs the neighbour entry hung off the DST for certain things
on transmit.

Arnd can't remember exactly why he even needed this change.

Conflicts:

	drivers/net/macvlan.c
	net/8021q/vlan_dev.c
	net/core/dev.c
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -259,7 +259,7 @@ static int macvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
 
 xmit_world:
 	skb->ip_summed = ip_summed;
-	skb_set_dev(skb, vlan->lowerdev);
+	skb->dev = vlan->lowerdev;
 	return dev_queue_xmit(skb);
 }
 

include/linux/netdevice.h

@@ -1403,15 +1403,6 @@ static inline bool netdev_uses_dsa_tags(struct net_device *dev)
 	return 0;
 }
 
-#ifndef CONFIG_NET_NS
-static inline void skb_set_dev(struct sk_buff *skb, struct net_device *dev)
-{
-	skb->dev = dev;
-}
-#else /* CONFIG_NET_NS */
-void skb_set_dev(struct sk_buff *skb, struct net_device *dev);
-#endif
-
 static inline bool netdev_uses_trailer_tags(struct net_device *dev)
 {
 #ifdef CONFIG_NET_DSA_TAG_TRAILER

net/8021q/vlan_dev.c

@@ -157,7 +157,7 @@ static netdev_tx_t vlan_dev_hard_start_xmit(struct sk_buff *skb,
 		skb = __vlan_hwaccel_put_tag(skb, vlan_tci);
 	}
 
-	skb_set_dev(skb, vlan_dev_priv(dev)->real_dev);
+	skb->dev = vlan_dev_priv(dev)->real_dev;
 	len = skb->len;
 	if (netpoll_tx_running(dev))
 		return skb->dev->netdev_ops->ndo_start_xmit(skb, skb->dev);

net/core/dev.c

@@ -1617,10 +1617,14 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
 		return NET_RX_DROP;
 	}
 	skb->skb_iif = 0;
-	skb_set_dev(skb, dev);
+	skb->dev = dev;
+	skb_dst_drop(skb);
 	skb->tstamp.tv64 = 0;
 	skb->pkt_type = PACKET_HOST;
 	skb->protocol = eth_type_trans(skb, dev);
+	skb->mark = 0;
+	secpath_reset(skb);
+	nf_reset(skb);
 	return netif_rx(skb);
 }
 EXPORT_SYMBOL_GPL(dev_forward_skb);
@@ -1869,36 +1873,6 @@ void netif_device_attach(struct net_device *dev)
 }
 EXPORT_SYMBOL(netif_device_attach);
 
-/**
- * skb_dev_set -- assign a new device to a buffer
- * @skb: buffer for the new device
- * @dev: network device
- *
- * If an skb is owned by a device already, we have to reset
- * all data private to the namespace a device belongs to
- * before assigning it a new device.
- */
-#ifdef CONFIG_NET_NS
-void skb_set_dev(struct sk_buff *skb, struct net_device *dev)
-{
-	skb_dst_drop(skb);
-	if (skb->dev && !net_eq(dev_net(skb->dev), dev_net(dev))) {
-		secpath_reset(skb);
-		nf_reset(skb);
-		skb_init_secmark(skb);
-		skb->mark = 0;
-		skb->priority = 0;
-		skb->nf_trace = 0;
-		skb->ipvs_property = 0;
-#ifdef CONFIG_NET_SCHED
-		skb->tc_index = 0;
-#endif
-	}
-	skb->dev = dev;
-}
-EXPORT_SYMBOL(skb_set_dev);
-#endif /* CONFIG_NET_NS */
-
 static void skb_warn_bad_offload(const struct sk_buff *skb)
 {
 	static const netdev_features_t null_features = 0;