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authorEric Dumazet <edumazet@google.com>2015-09-25 07:39:09 -0700
committerDavid S. Miller <davem@davemloft.net>2015-09-25 13:00:36 -0700
commitb1964b5fce389a5660139ca39c25ff294da07b4f (patch)
tree9e165bbd7f65719fa9f1330fe33edfa3f49b3e67 /net/ipv4/tcp_minisocks.c
parentb40cf18ef7961b6d67732e234780586590510ce1 (diff)
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/ipv4/tcp_minisocks.c')
-rw-r--r--net/ipv4/tcp_minisocks.c28
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,