From: Eric Dumazet <edumazet@google.com>
Date: Mon, 16 Apr 2012 23:28:07 +0000 (+0000)
Subject: tcp: fix tcp_grow_window() for large incoming frames
X-Git-Tag: v3.2.17~85
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=f8f811922bb85977a1c30f4788cca14b5741f9b9;hp=829a94ac60173dca2a30b65ea43c5c01150bd233;ds=sidebyside

tcp: fix tcp_grow_window() for large incoming frames

[ Upstream commit 4d846f02392a710f9604892ac3329e628e60a230 ]

tcp_grow_window() has to grow rcv_ssthresh up to window_clamp, allowing
sender to increase its window.

tcp_grow_window() still assumes a tcp frame is under MSS, but its no
longer true with LRO/GRO.

This patch fixes one of the performance issue we noticed with GRO on.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4c46fa7c451d..daedc0714aa6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -334,6 +334,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
 			incr = __tcp_grow_window(sk, skb);
 
 		if (incr) {
+			incr = max_t(int, incr, 2 * skb->len);
 			tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr,
 					       tp->window_clamp);
 			inet_csk(sk)->icsk_ack.quick |= 1;