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authorYuchung Cheng <ycheng@google.com>2017-01-12 22:11:41 -0800
committerDavid S. Miller <davem@davemloft.net>2017-01-13 22:37:16 -0500
commit4a7f6009441144783e5925551c72e3f2e1b0839b (patch)
tree41e521496a3c78abfcabb41f4a20f4f8c535887e /net/ipv4/tcp.c
parentac229dca7e4e582114e1ec9765fda0915aa58468 (diff)
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 <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c6
1 files changed, 2 insertions, 4 deletions
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: