From c19d292af95c4d99dc4d761515a44fb533271839 Mon Sep 17 00:00:00 2001
From: Neal Cardwell <ncardwell@google.com>
Date: Wed, 16 Nov 2011 08:58:02 +0000
Subject: [PATCH] --- yaml --- r: 277981 b: refs/heads/master c:
 5628adf1a0ff39b9e76e1a8e1c94dadabfd46914 h: refs/heads/master i:   277979:
 ca66eeb40a7d7b0ccb4b1cfba00cdc329d14fe78 v: v3

---
 [refs]                     | 2 +-
 trunk/net/ipv4/tcp_input.c | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index ac63156d9798..9083d15df039 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7d2b55f80d62b6b4b72d9ef4318a2a49df3e2830
+refs/heads/master: 5628adf1a0ff39b9e76e1a8e1c94dadabfd46914
diff --git a/trunk/net/ipv4/tcp_input.c b/trunk/net/ipv4/tcp_input.c
index f772aaa4319e..b49e41864037 100644
--- a/trunk/net/ipv4/tcp_input.c
+++ b/trunk/net/ipv4/tcp_input.c
@@ -3788,6 +3788,10 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	return 1;
 
 no_queue:
+	/* If data was DSACKed, see if we can undo a cwnd reduction. */
+	if (flag & FLAG_DSACKING_ACK)
+		tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked,
+				      is_dupack, flag);
 	/* If this ack opens up a zero window, clear backoff.  It was
 	 * being used to time the probes, and is probably far higher than
 	 * it needs to be for normal retransmission.