Revert Backoff [v3]: Rename skb to icmp_skb in tcp_v4_err()

This supplementary patch renames skb to icmp_skb in tcp_v4_err() in order to
disambiguate from another sk_buff variable, which will be introduced
in a separate patch.
Signed-off-by: NDamian Lukowski <damian@tvk.rwth-aachen.de>
Acked-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_ipv4.c

@@ -328,26 +328,26 @@ static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
  *
  */
 
-void tcp_v4_err(struct sk_buff *skb, u32 info)
+void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 {
-	struct iphdr *iph = (struct iphdr *)skb->data;
-	struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
+	struct iphdr *iph = (struct iphdr *)icmp_skb->data;
+	struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
 	struct tcp_sock *tp;
 	struct inet_sock *inet;
-	const int type = icmp_hdr(skb)->type;
-	const int code = icmp_hdr(skb)->code;
+	const int type = icmp_hdr(icmp_skb)->type;
+	const int code = icmp_hdr(icmp_skb)->code;
 	struct sock *sk;
 	__u32 seq;
 	int err;
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net(icmp_skb->dev);
 
-	if (skb->len < (iph->ihl << 2) + 8) {
+	if (icmp_skb->len < (iph->ihl << 2) + 8) {
 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 		return;
 	}
 
 	sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
-			iph->saddr, th->source, inet_iif(skb));
+			iph->saddr, th->source, inet_iif(icmp_skb));
 	if (!sk) {
 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 		return;