[PATCH 4.14 149/159] tcp: fix under-evaluated ssthresh in TCP Vegas

Greg Kroah-Hartman
2017-12-22T09:05:53Z

From: Hoang Tran <tranviethoang.vn@gmail.com>

[ Upstream commit cf5d74b85ef40c202c76d90959db4d850f301b95 ]

With the commit 76174004a0f19785 (tcp: do not slow start when cwnd equals
ssthresh), the comparison to the reduced cwnd in tcp_vegas_ssthresh() would
under-evaluate the ssthresh.

Signed-off-by: Hoang Tran <hoang.tran@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/tcp_vegas.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -158,7 +158,7 @@ EXPORT_SYMBOL_GPL(tcp_vegas_cwnd_event);

static inline u32 tcp_vegas_ssthresh(struct tcp_sock *tp)
{
- return min(tp->snd_ssthresh, tp->snd_cwnd-1);
+ return min(tp->snd_ssthresh, tp->snd_cwnd);
}

static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked)