net: udp: use skb_list_walk_safe helper for gso segments

This is a straight-forward conversion case for the new function,
iterating over the return value from udp_rcv_segment, which actually is
a wrapper around skb_gso_segment.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/udp.c

@@ -2104,8 +2104,7 @@ static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_SGO_CB_OFFSET);
 	__skb_push(skb, -skb_mac_offset(skb));
 	segs = udp_rcv_segment(sk, skb, true);
-	for (skb = segs; skb; skb = next) {
-		next = skb->next;
+	skb_list_walk_safe(segs, skb, next) {
 		__skb_pull(skb, skb_transport_offset(skb));
 		ret = udp_queue_rcv_one_skb(sk, skb);
 		if (ret > 0)

net/ipv6/udp.c

@@ -690,8 +690,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 	__skb_push(skb, -skb_mac_offset(skb));
 	segs = udp_rcv_segment(sk, skb, false);
-	for (skb = segs; skb; skb = next) {
-		next = skb->next;
+	skb_list_walk_safe(segs, skb, next) {
 		__skb_pull(skb, skb_transport_offset(skb));
 
 		ret = udpv6_queue_rcv_one_skb(sk, skb);