[patch 27/47] tcp: Limit cwnd growth when deferring for GSO

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: John Heffner <johnwheffner@xxxxxxxxx>

[ 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@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 net/ipv4/tcp_cong.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -287,7 +287,8 @@ int tcp_is_cwnd_limited(const struct soc
 
 	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);
 }

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