netdev - [PATCH net-next 06/11] tcp: move snd_cwnd & snd_cwnd_cnt init to tcp

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Date:   Thu, 17 Jan 2019 11:23:37 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        Soheil Hassas Yeganeh <soheil@...gle.com>,
        Neal Cardwell <ncardwell@...gle.com>,
        Yuchung Cheng <ycheng@...gle.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 06/11] tcp: move snd_cwnd & snd_cwnd_cnt init to tcp_disconnect()

Passive connections can inherit proper value by cloning,
if we make sure all listeners have the proper values there.

tcp_disconnect() was setting snd_cwnd to 2, which seems
quite obsolete since IW10 adoption.

Also remove an obsolete comment.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/tcp.c           | 2 +-
 net/ipv4/tcp_minisocks.c | 8 --------
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 731b1c6e88a992e51b9e303803444dc255d888fa..3f99ad92eaedb2364e339842365f553fca8922e1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2578,10 +2578,10 @@ int tcp_disconnect(struct sock *sk, int flags)
 	if (tp->write_seq == 0)
 		tp->write_seq = 1;
 	icsk->icsk_backoff = 0;
-	tp->snd_cwnd = 2;
 	icsk->icsk_probes_out = 0;
 	icsk->icsk_rto = TCP_TIMEOUT_INIT;
 	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
+	tp->snd_cwnd = TCP_INIT_CWND;
 	tp->snd_cwnd_cnt = 0;
 	tp->window_clamp = 0;
 	tp->delivered_ce = 0;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 35906b44e2cfa767f760773d0321a992114fee5b..ca96e7da99b6e450a5e881e280ad84137a57409d 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -490,14 +490,6 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 	newtp->last_oow_ack_time = 0;
 	newtp->total_retrans = req->num_retrans;
 
-	/* So many TCP implementations out there (incorrectly) count the
-	 * initial SYN frame in their delayed-ACK and congestion control
-	 * algorithms that we must have the following bandaid to talk
-	 * efficiently to them.  -DaveM
-	 */
-	newtp->snd_cwnd = TCP_INIT_CWND;
-	newtp->snd_cwnd_cnt = 0;
-
 	/* There's a bubble in the pipe until at least the first ACK. */
 	newtp->app_limited = ~0U;
 
-- 
2.20.1.321.g9e740568ce-goog