net: restore tx timestamping for accelerated vlans

Since commit 9b22ea5
( net: fix packet socket delivery in rx irq handler )

We lost rx timestamping of packets received on accelerated vlans.

Effect is that tcpdump on real dev can show strange timings, since it gets rx timestamps
too late (ie at skb dequeueing time, not at skb queueing time)

14:47:26.986871 IP 192.168.20.110 > 192.168.20.141: icmp 64: echo request seq 1
14:47:26.986786 IP 192.168.20.141 > 192.168.20.110: icmp 64: echo reply seq 1

14:47:27.986888 IP 192.168.20.110 > 192.168.20.141: icmp 64: echo request seq 2
14:47:27.986781 IP 192.168.20.141 > 192.168.20.110: icmp 64: echo reply seq 2

14:47:28.986896 IP 192.168.20.110 > 192.168.20.141: icmp 64: echo request seq 3
14:47:28.986780 IP 192.168.20.141 > 192.168.20.110: icmp 64: echo reply seq 3

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2288,16 +2288,16 @@ int netif_receive_skb(struct sk_buff *skb)
 	int ret = NET_RX_DROP;
 	__be16 type;
 
+	if (!skb->tstamp.tv64)
+		net_timestamp(skb);
+
 	if (skb->vlan_tci && vlan_hwaccel_do_receive(skb))
 		return NET_RX_SUCCESS;
 
 	/* if we've gotten here through NAPI, check netpoll */
 	if (netpoll_receive_skb(skb))
 		return NET_RX_DROP;
 
-	if (!skb->tstamp.tv64)
-		net_timestamp(skb);
-
 	if (!skb->iif)
 		skb->iif = skb->dev->ifindex;