From 5528e568a760442e0ec8fd2dea1f0791875a066b Mon Sep 17 00:00:00 2001 From: John Heffner Date: Fri, 5 May 2006 17:41:44 -0700 Subject: [PATCH] [TCP]: Fix snd_cwnd adjustments in tcp_highspeed.c Xiaoliang (David) Wei wrote: > Hi gurus, > > I am reading the code of tcp_highspeed.c in the kernel and have a > question on the hstcp_cong_avoid function, specifically the following > AI part (line 136~143 in net/ipv4/tcp_highspeed.c ): > > /* Do additive increase */ > if (tp->snd_cwnd < tp->snd_cwnd_clamp) { > tp->snd_cwnd_cnt += ca->ai; > if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { > tp->snd_cwnd++; > tp->snd_cwnd_cnt -= tp->snd_cwnd; > } > } > > In this part, when (tp->snd_cwnd_cnt == tp->snd_cwnd), > snd_cwnd_cnt will be -1... snd_cwnd_cnt is defined as u16, will this > small chance of getting -1 becomes a problem? > Shall we change it by reversing the order of the cwnd++ and cwnd_cnt -= > cwnd? Absolutely correct. Thanks. Signed-off-by: John Heffner Signed-off-by: David S. Miller --- net/ipv4/tcp_highspeed.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c index e0e9d1383c..b72fa55dfb 100644 --- a/net/ipv4/tcp_highspeed.c +++ b/net/ipv4/tcp_highspeed.c @@ -137,8 +137,8 @@ static void hstcp_cong_avoid(struct sock *sk, u32 adk, u32 rtt, if (tp->snd_cwnd < tp->snd_cwnd_clamp) { tp->snd_cwnd_cnt += ca->ai; if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { - tp->snd_cwnd++; tp->snd_cwnd_cnt -= tp->snd_cwnd; + tp->snd_cwnd++; } } } -- 2.39.5