knfsd: simplify a 'while' condition in svcsock.c

This while loop has an overly complex condition, which performs a couple of
assignments.  This hurts readability.

We don't really need a loop at all.  We can just return -EAGAIN and (providing
we set SK_DATA), the function will be called again.

So discard the loop, make the complex conditional become a few clear function
calls, and hopefully improve readability.
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

net/sunrpc/svcsock.c

@@ -788,15 +788,20 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 	}
 
 	clear_bit(SK_DATA, &svsk->sk_flags);
-	while ((err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
-				     0, 0, MSG_PEEK | MSG_DONTWAIT)) < 0 ||
-	       (skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err)) == NULL) {
-		if (err == -EAGAIN) {
-			svc_sock_received(svsk);
-			return err;
-		}
+	skb = NULL;
+	err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
+			     0, 0, MSG_PEEK | MSG_DONTWAIT);
+	if (err >= 0)
+		skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err);
+
+	if (skb == NULL) {
+		if (err != -EAGAIN) {
 			/* possibly an icmp error */
 			dprintk("svc: recvfrom returned error %d\n", -err);
+			set_bit(SK_DATA, &svsk->sk_flags);
+		}
+		svc_sock_received(svsk);
+		return -EAGAIN;
 	}
 	rqstp->rq_addrlen = sizeof(rqstp->rq_addr);
 	if (skb->tstamp.tv64 == 0) {