From: John Heffner <johnwheffner@gmail.com>
Date: Tue, 29 Apr 2008 10:13:52 +0000 (-0700)
Subject: tcp: Limit cwnd growth when deferring for GSO
X-Git-Tag: v2.6.25.7~21
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=413b0a22cad909f8cf86299ecf37d34df5d1eb38;p=thirdparty%2Fkernel%2Fstable.git

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 bfb1996bd99ff..fde71461e2279 100644
--- 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);
 }