[NET]: Treat CHECKSUM_PARTIAL as CHECKSUM_UNNECESSARY

When a transmitted packet is looped back directly, CHECKSUM_PARTIAL
maps to the semantics of CHECKSUM_UNNECESSARY.  Therefore we should
treat it as such in the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 2b3be68..f65fcd7 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -368,7 +368,7 @@
 				     skb->len, inet->num, skb->csum))
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
 	}
-	if (skb->ip_summed != CHECKSUM_UNNECESSARY)
+	if (!skb_csum_unnecessary(skb))
 		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
 							 &ipv6_hdr(skb)->daddr,
 							 skb->len,
@@ -421,7 +421,7 @@
 		msg->msg_flags |= MSG_TRUNC;
 	}
 
-	if (skb->ip_summed==CHECKSUM_UNNECESSARY) {
+	if (skb_csum_unnecessary(skb)) {
 		err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 	} else if (msg->msg_flags&MSG_TRUNC) {
 		if (__skb_checksum_complete(skb))
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7e824b9..2b668a6 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1707,8 +1707,7 @@
 	if (!pskb_may_pull(skb, th->doff*4))
 		goto discard_it;
 
-	if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
-	     tcp_v6_checksum_init(skb)))
+	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
 		goto bad_packet;
 
 	th = tcp_hdr(skb);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1e3dfb2..b083c09 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -153,7 +153,7 @@
 			goto csum_copy_err;
 	}
 
-	if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+	if (skb_csum_unnecessary(skb))
 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
 					      msg->msg_iov, copied       );
 	else {
@@ -397,7 +397,7 @@
 			     skb->len, proto, skb->csum))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-	if (skb->ip_summed != CHECKSUM_UNNECESSARY)
+	if (!skb_csum_unnecessary(skb))
 		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
 							 &ipv6_hdr(skb)->daddr,
 							 skb->len, proto, 0));