From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35619 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753696AbcHRN4L (ORCPT ); Thu, 18 Aug 2016 09:56:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yue Cao , Eric Dumazet , Linus Torvalds , Yuchung Cheng , Neal Cardwell , "David S. Miller" , Chas Williams , Willy Tarreau Subject: [PATCH 3.14 01/46] tcp: make challenge acks faster Date: Thu, 18 Aug 2016 15:54:23 +0200 Message-Id: <20160818135442.667643165@linuxfoundation.org> In-Reply-To: <20160818135442.457400364@linuxfoundation.org> References: <20160818135442.457400364@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman When backporting upstream commit 75ff39ccc1bd ("tcp: make challenge acks less predictable") I negelected to use the correct ACCESS* type macros. This fixes that up to hopefully speed things up a bit more. Thanks to Chas Wiliams for the 3.10 backport which reminded me of this. Cc: Yue Cao Cc: Eric Dumazet Cc: Linus Torvalds Cc: Yuchung Cheng Cc: Neal Cardwell Cc: Neal Cardwell Cc: Yuchung Cheng Cc: David S. Miller Cc: Chas Williams Cc: Willy Tarreau Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3299,12 +3299,12 @@ static void tcp_send_challenge_ack(struc u32 half = (sysctl_tcp_challenge_ack_limit + 1) >> 1; challenge_timestamp = now; - challenge_count = half + + ACCESS_ONCE(challenge_count) = half + prandom_u32_max(sysctl_tcp_challenge_ack_limit); } - count = challenge_count; + count = ACCESS_ONCE(challenge_count); if (count > 0) { - challenge_count = count - 1; + ACCESS_ONCE(challenge_count) = count - 1; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK); tcp_send_ack(sk); }