x25: '< 0' and '>= 0' test on unsigned

skb->len is an unsigned int, so the test in x25_rx_call_request() always
evaluates to true.

len in x25_sendmsg() is unsigned as well. so -ERRORS returned by x25_output()
are not noticed.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/x25/af_x25.c

@@ -951,10 +951,8 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
 	/*
 	 *	Incoming Call User Data.
 	 */
-	if (skb->len >= 0) {
 	skb_copy_from_linear_data(skb, makex25->calluserdata.cuddata, skb->len);
 	makex25->calluserdata.cudlength = skb->len;
-	}
 
 	sk->sk_ack_backlog++;
 
@@ -1122,8 +1120,9 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
 	if (msg->msg_flags & MSG_OOB)
 		skb_queue_tail(&x25->interrupt_out_queue, skb);
 	else {
-		len = x25_output(sk, skb);
-		if (len < 0)
+		rc = x25_output(sk, skb);
+		len = rc;
+		if (rc < 0)
 			kfree_skb(skb);
 		else if (x25->qbitincl)
 			len++;