[TCP]: Fixes IW > 2 cases when TCP is application limited

Whenever a transfer is application limited, we are allowed at least
initial window worth of data per window unless cwnd is previously
less than that.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 738dad9f7d49..104af5d5bcbc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3541,7 +3541,8 @@ void tcp_cwnd_application_limited(struct sock *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 win_used = max(tp->snd_cwnd_used, 2U);
+                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;