[PATCH RESEND net-next v2 1/5] tcp: fix stretch ACK bugs in BIC

From: Pengcheng Yang
Date: Mon Mar 16 2020 - 02:55:44 EST


Changes BIC to properly handle stretch ACKs in additive
increase mode by passing in the count of ACKed packets
to tcp_cong_avoid_ai().

Signed-off-by: Pengcheng Yang <yangpc@xxxxxxxxxx>
---
net/ipv4/tcp_bic.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c
index 645cc30..f5f588b 100644
--- a/net/ipv4/tcp_bic.c
+++ b/net/ipv4/tcp_bic.c
@@ -145,12 +145,13 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
if (!tcp_is_cwnd_limited(sk))
return;

- if (tcp_in_slow_start(tp))
- tcp_slow_start(tp, acked);
- else {
- bictcp_update(ca, tp->snd_cwnd);
- tcp_cong_avoid_ai(tp, ca->cnt, 1);
+ if (tcp_in_slow_start(tp)) {
+ acked = tcp_slow_start(tp, acked);
+ if (!acked)
+ return;
}
+ bictcp_update(ca, tp->snd_cwnd);
+ tcp_cong_avoid_ai(tp, ca->cnt, acked);
}

/*
--
1.8.3.1