udp: remove unreachable ufo branches

Remove two references to ufo in the udp send path that are no longer
reachable now that ufo has been removed.

Commit 85f1bd9a7b5a ("udp: consistently apply ufo or fragmentation")
is a fix to ufo. It is safe to revert what remains of it.

Also, no skb can enter ip_append_page with skb_is_gso true now that
skb_shinfo(skb)->gso_type is no longer set in ip_append_page/_data.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_output.c

@@ -1223,15 +1223,11 @@ ssize_t	ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 	cork->length += size;
 
 	while (size > 0) {
-		if (skb_is_gso(skb)) {
-			len = size;
-		} else {
+		/* Check if the remaining data fits into current packet. */
+		len = mtu - skb->len;
+		if (len < size)
+			len = maxfraglen - skb->len;
 
-			/* Check if the remaining data fits into current packet. */
-			len = mtu - skb->len;
-			if (len < size)
-				len = maxfraglen - skb->len;
-		}
 		if (len <= 0) {
 			struct sk_buff *skb_prev;
 			int alloclen;

net/ipv4/udp.c

@@ -809,7 +809,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 	if (is_udplite)  				 /*     UDP-Lite      */
 		csum = udplite_csum(skb);
 
-	else if (sk->sk_no_check_tx && !skb_is_gso(skb)) {   /* UDP csum off */
+	else if (sk->sk_no_check_tx) {			 /* UDP csum off */
 
 		skb->ip_summed = CHECKSUM_NONE;
 		goto send;