net: Postpone skb_clear_delivery_time() until knowing the skb is delivered locally

The previous patches handled the delivery_time in the ingress path
before the routing decision is made.  This patch can postpone clearing
delivery_time in a skb until knowing it is delivered locally and also
set the (rcv) timestamp if needed.  This patch moves the
skb_clear_delivery_time() from dev.c to ip_local_deliver_finish()
and ip6_input_finish().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -5220,10 +5220,8 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 			goto out;
 	}
 
-	if (skb_skip_tc_classify(skb)) {
-		skb_clear_delivery_time(skb);
+	if (skb_skip_tc_classify(skb))
 		goto skip_classify;
-	}
 
 	if (pfmemalloc)
 		goto skip_taps;
@@ -5252,14 +5250,12 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 			goto another_round;
 		if (!skb)
 			goto out;
-		skb_clear_delivery_time(skb);
 
 		nf_skip_egress(skb, false);
 		if (nf_ingress(skb, &pt_prev, &ret, orig_dev) < 0)
 			goto out;
-	} else
+	}
 #endif
-		skb_clear_delivery_time(skb);
 	skb_reset_redirect(skb);
 skip_classify:
 	if (pfmemalloc && !skb_pfmemalloc_protocol(skb))

net/ipv4/ip_input.c

@@ -226,6 +226,7 @@ void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol)
 
 static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
+	skb_clear_delivery_time(skb);
 	__skb_pull(skb, skb_network_header_len(skb));
 
 	rcu_read_lock();

net/ipv6/ip6_input.c

@@ -459,6 +459,7 @@ void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
 
 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
+	skb_clear_delivery_time(skb);
 	rcu_read_lock();
 	ip6_protocol_deliver_rcu(net, skb, 0, false);
 	rcu_read_unlock();