[PATCH 4.4 58/79] tcp: remove DELAYED ACK events in DCTCP

Greg Kroah-Hartman
2018-08-23T08:01:24Z

From: Yuchung Cheng <ycheng@google.com>

[ Upstream commit a69258f7aa2623e0930212f09c586fd06674ad79 ]

After fixing the way DCTCP tracking delayed ACKs, the delayed-ACK
related callbacks are no longer needed

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/tcp.h | 2 --
net/ipv4/tcp_dctcp.c | 25 -------------------------
net/ipv4/tcp_output.c | 4 ----
3 files changed, 31 deletions(-)

--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -821,8 +821,6 @@ enum tcp_ca_event {
CA_EVENT_LOSS, /* loss timeout */
CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
- CA_EVENT_DELAYED_ACK, /* Delayed ack is sent */
- CA_EVENT_NON_DELAYED_ACK,
};

/* Information about inbound ACK, passed to cong_ops->in_ack_event() */
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -55,7 +55,6 @@ struct dctcp {
u32 dctcp_alpha;
u32 next_seq;
u32 ce_state;
- u32 delayed_ack_reserved;
u32 loss_cwnd;
};

@@ -96,7 +95,6 @@ static void dctcp_init(struct sock *sk)

ca->dctcp_alpha = min(dctcp_alpha_on_init, DCTCP_MAX_ALPHA);

- ca->delayed_ack_reserved = 0;
ca->loss_cwnd = 0;
ca->ce_state = 0;

@@ -230,25 +228,6 @@ static void dctcp_state(struct sock *sk,
}
}

-static void dctcp_update_ack_reserved(struct sock *sk, enum tcp_ca_event ev)
-{
- struct dctcp *ca = inet_csk_ca(sk);
-
- switch (ev) {
- case CA_EVENT_DELAYED_ACK:
- if (!ca->delayed_ack_reserved)
- ca->delayed_ack_reserved = 1;
- break;
- case CA_EVENT_NON_DELAYED_ACK:
- if (ca->delayed_ack_reserved)
- ca->delayed_ack_reserved = 0;
- break;
- default:
- /* Don't care for the rest. */
- break;
- }
-}
-
static void dctcp_cwnd_event(struct sock *sk, enum tcp_ca_event ev)
{
switch (ev) {
@@ -258,10 +237,6 @@ static void dctcp_cwnd_event(struct sock
case CA_EVENT_ECN_NO_CE:
dctcp_ce_state_1_to_0(sk);
break;
- case CA_EVENT_DELAYED_ACK:
- case CA_EVENT_NON_DELAYED_ACK:
- dctcp_update_ack_reserved(sk, ev);
- break;
default:
/* Don't care for the rest. */
break;
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3316,8 +3316,6 @@ void tcp_send_delayed_ack(struct sock *s
int ato = icsk->icsk_ack.ato;
unsigned long timeout;

- tcp_ca_event(sk, CA_EVENT_DELAYED_ACK);
-
if (ato > TCP_DELACK_MIN) {
const struct tcp_sock *tp = tcp_sk(sk);
int max_ato = HZ / 2;
@@ -3374,8 +3372,6 @@ void __tcp_send_ack(struct sock *sk, u32
if (sk->sk_state == TCP_CLOSE)
return;

- tcp_ca_event(sk, CA_EVENT_NON_DELAYED_ACK);
-
/* We are not putting this on the write queue, so
* tcp_transmit_skb() will set the ownership to this
* sock.