From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752744AbbC0Vuk (ORCPT ); Fri, 27 Mar 2015 17:50:40 -0400 Received: from smtprelay0179.hostedemail.com ([216.40.44.179]:46937 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751850AbbC0Vug (ORCPT ); Fri, 27 Mar 2015 17:50:36 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 50,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::,RULES_HIT:41:69:355:379:541:800:960:967:968:973:988:989:1260:1263:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2194:2199:2393:2525:2553:2560:2563:2682:2685:2859:2897:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3352:3770:3865:3866:3867:3868:3870:3871:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:4605:5007:6261:7266:8599:9025:9108:9121:10004:10400:10848:11026:11233:11658:11914:12043:12262:12438:12517:12519:12555:12679:12740:13069:13311:13357:13846:14094:14096:14394:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: nail44_516758bb0837 X-Filterd-Recvd-Size: 2626 Date: Fri, 27 Mar 2015 17:50:33 -0400 From: Steven Rostedt To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , stable@vger.kernel.org, Uwe Kleine-Koenig Subject: [PATCH] ring-buffer: Remove duplicate use of '&' in recursive code Message-ID: <20150327175033.66ca3553@gandalf.local.home> In-Reply-To: References: <20150325130011.709478161@goodmis.org> <20150325130037.896265791@goodmis.org> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Steven Rostedt (Red Hat) (1): ring-buffer: Remove duplicate use of '&' in recursive code ---- kernel/trace/ring_buffer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --------------------------- commit 7eb867195b9f3990da60738b1f26d0a71f37f77f Author: Steven Rostedt (Red Hat) Date: Fri Mar 27 17:39:49 2015 -0400 ring-buffer: Remove duplicate use of '&' in recursive code A clean up of the recursive protection code changed val = this_cpu_read(current_context); val--; val &= this_cpu_read(current_context); to val = this_cpu_read(current_context); val &= val & (val - 1); Which has a duplicate use of '&' as the above is the same as val = val & (val - 1); Actually, it would be best to remove that line altogether and just add it to where it is used. Link: http://lkml.kernel.org/alpine.DEB.2.11.1503271423580.23114@gentwo.org Suggested-by: Christoph Lameter Signed-off-by: Steven Rostedt diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 922048a0f7ea..93caf56567cb 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2705,8 +2705,7 @@ static __always_inline void trace_recursive_unlock(void) { unsigned int val = __this_cpu_read(current_context); - val &= val & (val - 1); - __this_cpu_write(current_context, val); + __this_cpu_write(current_context, val & (val - 1)); } #else