From: Neal Cardwell <ncardwell@google.com>
Date: Wed, 16 Nov 2011 08:58:05 +0000 (+0000)
Subject: tcp: skip cwnd moderation in TCP_CA_Open in tcp_try_to_open
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8cd6d6162d998da579d40a1ee061bf8ce1610ff8;p=linux-beck.git

tcp: skip cwnd moderation in TCP_CA_Open in tcp_try_to_open

The problem: Senders were overriding cwnd values picked during an undo
by calling tcp_moderate_cwnd() in tcp_try_to_open().

The fix: Don't moderate cwnd in tcp_try_to_open() if we're in
TCP_CA_Open, since doing so is generally unnecessary and specifically
would override a DSACK-based undo of a cwnd reduction made in fast
recovery.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a4efdd7cf5a1..78dd38cd5496 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2881,7 +2881,8 @@ static void tcp_try_to_open(struct sock *sk, int flag)
 
 	if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) {
 		tcp_try_keep_open(sk);
-		tcp_moderate_cwnd(tp);
+		if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open)
+			tcp_moderate_cwnd(tp);
 	} else {
 		tcp_cwnd_down(sk, flag);
 	}