[TCP]: Move __tcp_data_snd_check into tcp_output.c

It reimplements portions of tcp_snd_check(), so it
we move it to tcp_output.c we can consolidate it's
logic much easier in a later change.

Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -849,6 +849,7 @@ extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
 /* tcp_output.c */
 
 extern int tcp_write_xmit(struct sock *, int nonagle);
+extern void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb);
 extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
 				      unsigned cur_mss, int nonagle);
 extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp);

net/ipv4/tcp_input.c

@@ -3346,16 +3346,6 @@ static inline void tcp_check_space(struct sock *sk)
 	}
 }
 
-static void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-
-	if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||
-	    tcp_packets_in_flight(tp) >= tp->snd_cwnd ||
-	    tcp_write_xmit(sk, tp->nonagle))
-		tcp_check_probe_timer(sk, tp);
-}
-
 static __inline__ void tcp_data_snd_check(struct sock *sk)
 {
 	struct sk_buff *skb = sk->sk_send_head;

net/ipv4/tcp_output.c

@@ -530,6 +530,16 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
 	tcp_cwnd_validate(sk, tp);
 }
 
+void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||
+	    tcp_packets_in_flight(tp) >= tp->snd_cwnd ||
+	    tcp_write_xmit(sk, tp->nonagle))
+		tcp_check_probe_timer(sk, tp);
+}
+
 int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp)
 {
 	struct sk_buff *skb = sk->sk_send_head;