net: sk_drops consolidation part 2

- skb_kill_datagram() can increment sk->sk_drops itself, not callers.

- UDP on IPV4 & IPV6 dropped frames (because of bad checksum or policy checks) increment sk_drops

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ec5c7a7..4274c1c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -867,6 +867,7 @@
 		udp_lib_checksum_complete(skb)) {
 		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
 				 IS_UDPLITE(sk));
+		atomic_inc(&sk->sk_drops);
 		__skb_unlink(skb, rcvq);
 		__skb_queue_tail(&list_kill, skb);
 	}
@@ -1186,6 +1187,7 @@
 
 drop:
 	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+	atomic_inc(&sk->sk_drops);
 	kfree_skb(skb);
 	return -1;
 }