tcp: make tcp_cwnd_application_limited() static

Make tcp_cwnd_application_limited() static and move it from tcp_input.c to
tcp_output.c

Signed-off-by: Weiping Pan <wpan@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 025e25093984..29dde97c3c41 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1387,6 +1387,28 @@ unsigned int tcp_current_mss(struct sock *sk)
         return mss_now;
 }
 
+/* RFC2861, slow part. Adjust cwnd, after it was not full during one rto.
+ * As additional protections, we do not touch cwnd in retransmission phases,
+ * and if application hit its sndbuf limit recently.
+ */
+static void tcp_cwnd_application_limited(struct sock *sk)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+
+        if (inet_csk(sk)->icsk_ca_state == TCP_CA_Open &&
+            sk->sk_socket && !test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
+                /* Limited by application or receiver window. */
+                u32 init_win = tcp_init_cwnd(tp, __sk_dst_get(sk));
+                u32 win_used = max(tp->snd_cwnd_used, init_win);
+                if (win_used < tp->snd_cwnd) {
+                        tp->snd_ssthresh = tcp_current_ssthresh(sk);
+                        tp->snd_cwnd = (tp->snd_cwnd + win_used) >> 1;
+                }
+                tp->snd_cwnd_used = 0;
+        }
+        tp->snd_cwnd_stamp = tcp_time_stamp;
+}
+
 /* Congestion window validation. (RFC2861) */
 static void tcp_cwnd_validate(struct sock *sk)
 {