[TCP]: Kill extra cwnd validate in __tcp_push_pending_frames().

The tcp_cwnd_validate() function should only be invoked
if we actually send some frames, yet __tcp_push_pending_frames()
will always invoke it.  tcp_write_xmit() does the call for us,
so the call here can simply be removed.

Also, tcp_write_xmit() can be marked static.

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

1 files changed, 49 insertions, 30 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 5e63ed09658..a6375ca2a59 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -511,35 +511,6 @@ static inline int tcp_skb_is_last(const struct sock *sk,
         return skb->next == (struct sk_buff *)&sk->sk_write_queue;
 }
 
-/* Push out any pending frames which were held back due to
- * TCP_CORK or attempt at coalescing tiny packets.
- * The socket must be locked by the caller.
- */
-void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
-                               unsigned cur_mss, int nonagle)
-{
-        struct sk_buff *skb = sk->sk_send_head;
-
-        if (skb) {
-                if (!tcp_skb_is_last(sk, skb))
-                        nonagle = TCP_NAGLE_PUSH;
-                if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||
-                    tcp_write_xmit(sk, nonagle))
-                        tcp_check_probe_timer(sk, 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;
@@ -841,6 +812,26 @@ unsigned int tcp_current_mss(struct sock *sk, int large)
         return mss_now;
 }
 
+/* Congestion window validation. (RFC2861) */
+
+static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
+{
+        __u32 packets_out = tp->packets_out;
+
+        if (packets_out >= tp->snd_cwnd) {
+                /* Network is feed fully. */
+                tp->snd_cwnd_used = 0;
+                tp->snd_cwnd_stamp = tcp_time_stamp;
+        } else {
+                /* Network starves. */
+                if (tp->packets_out > tp->snd_cwnd_used)
+                        tp->snd_cwnd_used = tp->packets_out;
+
+                if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)
+                        tcp_cwnd_application_limited(sk);
+        }
+}
+
 /* This routine writes packets to the network.  It advances the
  * send_head.  This happens as incoming acks open up the remote
  * window for us.
@@ -848,7 +839,7 @@ unsigned int tcp_current_mss(struct sock *sk, int large)
  * Returns 1, if no segments are in flight and we have queued segments, but
  * cannot send anything now because of SWS or another problem.
  */
-int tcp_write_xmit(struct sock *sk, int nonagle)
+static int tcp_write_xmit(struct sock *sk, int nonagle)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         unsigned int mss_now;
@@ -901,6 +892,34 @@ int tcp_write_xmit(struct sock *sk, int nonagle)
         return 0;
 }
 
+/* Push out any pending frames which were held back due to
+ * TCP_CORK or attempt at coalescing tiny packets.
+ * The socket must be locked by the caller.
+ */
+void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
+                               unsigned cur_mss, int nonagle)
+{
+        struct sk_buff *skb = sk->sk_send_head;
+
+        if (skb) {
+                if (!tcp_skb_is_last(sk, skb))
+                        nonagle = TCP_NAGLE_PUSH;
+                if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||
+                    tcp_write_xmit(sk, nonagle))
+                        tcp_check_probe_timer(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);
+}
+
 /* This function returns the amount that we can raise the
  * usable window based on the following constraints
  *