diff mbox series

[net-next,1/3] tcp: do not overshoot window_clamp in tcp_rcv_space_adjust()

Message ID 20171211015504.26551-2-edumazet@google.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series tcp: better receiver autotuning | expand

Commit Message

Eric Dumazet Dec. 11, 2017, 1:55 a.m. UTC 
While rcvbuf is properly clamped by tcp_rmem[2], rcvwin
is left to a potentially too big value.

It has no serious effect, since :
1) tcp_grow_window() has very strict checks.
2) window_clamp can be mangled by user space to any value anyway.

tcp_init_buffer_space() and companions use tcp_full_space(),
we use tcp_win_from_space() to avoid reloading sk->sk_rcvbuf

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Wei Wang <weiwan@google.com>
---
 net/ipv4/tcp_input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Neal Cardwell Dec. 11, 2017, 5:47 p.m. UTC | #1 
On Sun, Dec 10, 2017 at 8:55 PM, Eric Dumazet <edumazet@google.com> wrote:
>
> While rcvbuf is properly clamped by tcp_rmem[2], rcvwin
> is left to a potentially too big value.
>
> It has no serious effect, since :
> 1) tcp_grow_window() has very strict checks.
> 2) window_clamp can be mangled by user space to any value anyway.
>
> tcp_init_buffer_space() and companions use tcp_full_space(),
> we use tcp_win_from_space() to avoid reloading sk->sk_rcvbuf
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
> Acked-by: Wei Wang <weiwan@google.com>
> ---

Acked-by: Neal Cardwell <ncardwell@google.com>

Thanks, Eric!

neal
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9550cc42de2d9ba4cca6d961a2a3bca501755a69..746a6773c482f5d419ddc9d7c9d52949cbb74cfb 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -631,7 +631,7 @@  void tcp_rcv_space_adjust(struct sock *sk)
 			sk->sk_rcvbuf = rcvbuf;
 
 			/* Make the window clamp follow along.  */
-			tp->window_clamp = rcvwin;
+			tp->window_clamp = tcp_win_from_space(sk, rcvbuf);
 		}
 	}
 	tp->rcvq_space.space = copied;