net: ipv4: use skb_list_walk_safe helper for gso segments

This is a straight-forward conversion case for the new function, keeping
the flow of the existing code as intact as possible.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ip_output.c

@@ -240,8 +240,8 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s
 static int ip_finish_output_gso(struct net *net, struct sock *sk,
 				struct sk_buff *skb, unsigned int mtu)
 {
+	struct sk_buff *segs, *nskb;
 	netdev_features_t features;
-	struct sk_buff *segs;
 	int ret = 0;
 
 	/* common case: seglen is <= mtu
@@ -272,8 +272,7 @@ static int ip_finish_output_gso(struct net *net, struct sock *sk,
 
 	consume_skb(skb);
 
-	do {
-		struct sk_buff *nskb = segs->next;
+	skb_list_walk_safe(segs, segs, nskb) {
 		int err;
 
 		skb_mark_not_on_list(segs);
@@ -281,8 +280,7 @@ static int ip_finish_output_gso(struct net *net, struct sock *sk,
 
 		if (err && ret == 0)
 			ret = err;
-		segs = nskb;
-	} while (segs);
+	}
 
 	return ret;
 }