diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-09-25 17:39:09 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-09-25 23:00:36 +0300 |
| commit | b1964b5fce389a5660139ca39c25ff294da07b4f (patch) | |
| tree | 9e165bbd7f65719fa9f1330fe33edfa3f49b3e67 /net | |
| parent | b40cf18ef7961b6d67732e234780586590510ce1 (diff) | |
| download | linux-b1964b5fce389a5660139ca39c25ff294da07b4f.tar.xz | |
tcp: constify tcp_openreq_init_rwin()
Soon, listener socket wont be locked when tcp_openreq_init_rwin()
is called. We need to read socket fields once, as their value
could change under us.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 85830bb92d04..e0a87c238882 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -362,27 +362,35 @@ void tcp_twsk_destructor(struct sock *sk) } EXPORT_SYMBOL_GPL(tcp_twsk_destructor); +/* Warning : This function is called without sk_listener being locked. + * Be sure to read socket fields once, as their value could change under us. + */ void tcp_openreq_init_rwin(struct request_sock *req, - struct sock *sk, struct dst_entry *dst) + const struct sock *sk_listener, + const struct dst_entry *dst) { struct inet_request_sock *ireq = inet_rsk(req); - struct tcp_sock *tp = tcp_sk(sk); - __u8 rcv_wscale; + const struct tcp_sock *tp = tcp_sk(sk_listener); + u16 user_mss = READ_ONCE(tp->rx_opt.user_mss); + int full_space = tcp_full_space(sk_listener); int mss = dst_metric_advmss(dst); + u32 window_clamp; + __u8 rcv_wscale; - if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss) - mss = tp->rx_opt.user_mss; + if (user_mss && user_mss < mss) + mss = user_mss; + window_clamp = READ_ONCE(tp->window_clamp); /* Set this up on the first call only */ - req->window_clamp = tp->window_clamp ? : dst_metric(dst, RTAX_WINDOW); + req->window_clamp = window_clamp ? : dst_metric(dst, RTAX_WINDOW); /* limit the window selection if the user enforce a smaller rx buffer */ - if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && - (req->window_clamp > tcp_full_space(sk) || req->window_clamp == 0)) - req->window_clamp = tcp_full_space(sk); + if (sk_listener->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->window_clamp > full_space || req->window_clamp == 0)) + req->window_clamp = full_space; /* tcp_full_space because it is guaranteed to be the first packet */ - tcp_select_initial_window(tcp_full_space(sk), + tcp_select_initial_window(full_space, mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0), &req->rcv_wnd, &req->window_clamp, |