Re: [PATCH net-next 4/6] tcp: remove header prediction
From: Neal Cardwell <ncardwell@google.com>
Date: 2017-08-01 17:24:27
On Sat, Jul 29, 2017 at 9:57 PM, Florian Westphal [off-list ref] wrote:
quoted hunk ↗ jump to hunk
@@ -5519,11 +5347,10 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) if (sock_flag(sk, SOCK_KEEPOPEN)) inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp)); - if (!tp->rx_opt.snd_wscale) - __tcp_fast_path_on(tp, tp->snd_wnd); - else - tp->pred_flags = 0; - + if (!sock_flag(sk, SOCK_DEAD)) { + sk->sk_state_change(sk); + sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); + } }
This patch hunk seems like it introduces a minor bug. It seems like after this change, the sk_state_change() and sk_wake_async() calls for a completed active connection happen twice: once in this new spot inside tcp_finish_connect() and once in the existing code in tcp_rcv_synsent_state_process() immediately after it calls tcp_finish_connect(). I would vote for removing this new code snippet and retaining the old one, in case there are subtle interactions with tcp_rcv_fastopen_synack(), which happens in between the new wake-up location and the old wake-up location. neal