From 4a7f6009441144783e5925551c72e3f2e1b0839b Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 12 Jan 2017 22:11:41 -0800 Subject: tcp: remove thin_dupack feature Thin stream DUPACK is to start fast recovery on only one DUPACK provided the connection is a thin stream (i.e., low inflight). But this older feature is now subsumed with RACK. If a connection receives only a single DUPACK, RACK would arm a reordering timer and soon starts fast recovery instead of timeout if no further ACKs are received. The socket option (THIN_DUPACK) is kept as a nop for compatibility. Note that this patch does not change another thin-stream feature which enables linear RTO. Although it might be good to generalize that in the future (i.e., linear RTO for the first say 3 retries). Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'net/ipv4/tcp.c') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index d9023e8ed53e..aba6ea76338e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2474,9 +2474,6 @@ static int do_tcp_setsockopt(struct sock *sk, int level, case TCP_THIN_DUPACK: if (val < 0 || val > 1) err = -EINVAL; - else { - tp->thin_dupack = val; - } break; case TCP_REPAIR: @@ -2966,8 +2963,9 @@ static int do_tcp_getsockopt(struct sock *sk, int level, case TCP_THIN_LINEAR_TIMEOUTS: val = tp->thin_lto; break; + case TCP_THIN_DUPACK: - val = tp->thin_dupack; + val = 0; break; case TCP_REPAIR: -- cgit v1.2.3