[PATCH net-next 8/8] tcp: refactor setting the initial congestion window

[Yuchung Cheng]

Relocate the congestion window initialization from tcp_init_metrics()
to tcp_init_transfer() to improve code readability.

Signed-off-by: Yuchung Cheng <ych...@google.com>
Signed-off-by: Neal Cardwell <ncardw...@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soh...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
 net/ipv4/tcp.c         | 12 ------------
 net/ipv4/tcp_input.c   | 26 ++++++++++++++++++++++++++
 net/ipv4/tcp_metrics.c | 10 ----------
 3 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f7567a3698eb..1fa15beb8380 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -457,18 +457,6 @@ void tcp_init_sock(struct sock *sk)
 }
 EXPORT_SYMBOL(tcp_init_sock);
 
-void tcp_init_transfer(struct sock *sk, int bpf_op)
-{
-       struct inet_connection_sock *icsk = inet_csk(sk);
-
-       tcp_mtup_init(sk);
-       icsk->icsk_af_ops->rebuild_header(sk);
-       tcp_init_metrics(sk);
-       tcp_call_bpf(sk, bpf_op, 0, NULL);
-       tcp_init_congestion_control(sk);
-       tcp_init_buffer_space(sk);
-}
-
 static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
 {
        struct sk_buff *skb = tcp_write_queue_tail(sk);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 706a99ec73f6..077d9abdfcf5 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5647,6 +5647,32 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff 
*skb)
 }
 EXPORT_SYMBOL(tcp_rcv_established);
 
+void tcp_init_transfer(struct sock *sk, int bpf_op)
+{
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       tcp_mtup_init(sk);
+       icsk->icsk_af_ops->rebuild_header(sk);
+       tcp_init_metrics(sk);
+
+       /* Initialize the congestion window to start the transfer.
+        * Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
+        * retransmitted. In light of RFC6298 more aggressive 1sec
+        * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
+        * retransmission has occurred.
+        */
+       if (tp->total_retrans > 1 && tp->undo_marker)
+               tp->snd_cwnd = 1;
+       else
+               tp->snd_cwnd = tcp_init_cwnd(tp, __sk_dst_get(sk));
+       tp->snd_cwnd_stamp = tcp_jiffies32;
+
+       tcp_call_bpf(sk, bpf_op, 0, NULL);
+       tcp_init_congestion_control(sk);
+       tcp_init_buffer_space(sk);
+}
+
 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index d4d687330e2b..c4848e7a0aad 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -512,16 +512,6 @@ void tcp_init_metrics(struct sock *sk)
 
                inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
        }
-       /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
-        * retransmitted. In light of RFC6298 more aggressive 1sec
-        * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
-        * retransmission has occurred.
-        */
-       if (tp->total_retrans > 1 && tp->undo_marker)
-               tp->snd_cwnd = 1;
-       else
-               tp->snd_cwnd = tcp_init_cwnd(tp, dst);
-       tp->snd_cwnd_stamp = tcp_jiffies32;
 }
 
 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
-- 
2.21.0.593.g511ec345e18-goog