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: v3.0.30~5
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=6a0e69cea2ec1499224067989470d3c929dbd67e;p=users%2Fdwmw2%2Flinux.git

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 104b02e3ee2a6..c3a9f033ef345 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -328,6 +328,7 @@ static void tcp_grow_window(struct sock *sk, 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;