sunrpc: do not pull udp headers on receive

Commit e6afc8ace6dd modified the udp receive path by pulling the udp
header before queuing an skbuff onto the receive queue.

Sunrpc also calls skb_recv_datagram to dequeue an skb from a udp
socket. Modify this receive path to also no longer expect udp
headers.

Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")

Reported-by: Franklin S Cooper Jr. <fcooper@ti.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 1413cdc..71d6072 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -617,7 +617,7 @@
 	svsk->sk_sk->sk_stamp = skb->tstamp;
 	set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
 
-	len  = skb->len - sizeof(struct udphdr);
+	len  = skb->len;
 	rqstp->rq_arg.len = len;
 
 	rqstp->rq_prot = IPPROTO_UDP;
@@ -641,8 +641,7 @@
 		skb_free_datagram_locked(svsk->sk_sk, skb);
 	} else {
 		/* we can use it in-place */
-		rqstp->rq_arg.head[0].iov_base = skb->data +
-			sizeof(struct udphdr);
+		rqstp->rq_arg.head[0].iov_base = skb->data;
 		rqstp->rq_arg.head[0].iov_len = len;
 		if (skb_checksum_complete(skb))
 			goto out_free;