[UDP]: Defer InDataGrams increment until recvmsg() does checksum

Thanks dave, herbert, gerrit, andi and other people for your
discussion about this problem.

UdpInDatagrams can be confusing because it counts packets that
might be dropped later.
Move UdpInDatagrams into recvmsg() as allowed by the RFC.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ee1cc3f8599f..b0474a618bbe 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -164,6 +164,8 @@ try_again:
         if (err)
                 goto out_free;
 
+        UDP6_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
+
         sock_recv_timestamp(msg, sk, skb);
 
         /* Copy the address. */
@@ -292,7 +294,7 @@ int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
                         UDP6_INC_STATS_BH(UDP_MIB_RCVBUFERRORS, up->pcflag);
                 goto drop;
         }
-        UDP6_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);
+
         return 0;
 drop:
         UDP6_INC_STATS_BH(UDP_MIB_INERRORS, up->pcflag);