[TCP]: Move FRTO checks out from write queue abstraction funcs

Better place exists in update_send_head (other non-queue related
adjustments are done there as well) which is the only caller of
tcp_advance_send_head (now that the bogus call from mtu_probe is
gone).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -1236,14 +1236,9 @@ static inline struct sk_buff *tcp_send_head(struct sock *sk)
 
 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
-
 	sk->sk_send_head = skb->next;
 	if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
 		sk->sk_send_head = NULL;
-	/* Don't override Nagle indefinately with F-RTO */
-	if (tp->frto_counter == 2)
-		tp->frto_counter = 3;
 }
 
 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)

net/ipv4/tcp_output.c

@@ -80,6 +80,10 @@ static void update_send_head(struct sock *sk, struct sk_buff *skb)
 	tcp_advance_send_head(sk, skb);
 	tp->snd_nxt = TCP_SKB_CB(skb)->end_seq;
 	tcp_packets_out_inc(sk, skb);
+
+	/* Don't override Nagle indefinately with F-RTO */
+	if (tp->frto_counter == 2)
+		tp->frto_counter = 3;
 }
 
 /* SND.NXT, if window was not shrunk.