[NET]: Detect hardware rx checksum faults correctly

Here is the patch that introduces the generic skb_checksum_complete
which also checks for hardware RX checksum faults.  If that happens,
it'll call netdev_rx_csum_fault which currently prints out a stack
trace with the device name.  In future it can turn off RX checksum.

I've converted every spot under net/ that does RX checksum checks to
use skb_checksum_complete or __skb_checksum_complete with the
exceptions of:

* Those places where checksums are done bit by bit.  These will call
netdev_rx_csum_fault directly.

* The following have not been completely checked/converted:

ipmr
ip_vs
netfilter
dccp

This patch is based on patches and suggestions from Stephen Hemminger
and David S. Miller.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 6 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index f16e7cdd615..e50e7cf4373 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -623,12 +623,9 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 		/* we can use it in-place */
 		rqstp->rq_arg.head[0].iov_base = skb->data + sizeof(struct udphdr);
 		rqstp->rq_arg.head[0].iov_len = len;
-		if (skb->ip_summed != CHECKSUM_UNNECESSARY) {
-			if ((unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum))) {
-				skb_free_datagram(svsk->sk_sk, skb);
-				return 0;
-			}
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		if (skb_checksum_complete(skb)) {
+			skb_free_datagram(svsk->sk_sk, skb);
+			return 0;
 		}
 		rqstp->rq_skbuff = skb;
 	}