tcp: Limit cwnd growth when deferring for GSO

[ upstream commit: 246eb2af060fc32650f07203c02bdc0456ad76c7 ]

This fixes inappropriately large cwnd growth on sender-limited flows
when GSO is enabled, limiting cwnd growth to 64k.

[ Backport to 2.6.25 by replacing sk->sk_gso_max_size with 65536 -DaveM ]

Signed-off-by: John Heffner <johnwheffner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index bfb1996bd99ff420af679d181017834f24d7b888..fde71461e22799ec27034dd4953cfc0187cfdef4 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -287,7 +287,8 @@ int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
 
        left = tp->snd_cwnd - in_flight;
        if (sk_can_gso(sk) &&
-           left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd)
+           left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd &&
+           left * tp->mss_cache < 65536)
                return 1;
        return left <= tcp_max_burst(tp);
 }