Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756145AbcCOLGr (ORCPT ); Tue, 15 Mar 2016 07:06:47 -0400 Received: from casper.infradead.org ([85.118.1.10]:52164 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754777AbcCOLGh (ORCPT ); Tue, 15 Mar 2016 07:06:37 -0400 Date: Tue, 15 Mar 2016 12:06:33 +0100 From: Peter Zijlstra To: Ingo Molnar Cc: Linus Torvalds , Linux Kernel Mailing List , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Thomas Gleixner , Andrew Morton Subject: Re: [PATCH] atomic: Fix bugs in 'fetch_or()' and rename it to 'xchg_or()' Message-ID: <20160315110633.GV6344@twins.programming.kicks-ass.net> References: <20160314123200.GA15971@gmail.com> <20160315093245.GA7943@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160315093245.GA7943@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 934 Lines: 26 On Tue, Mar 15, 2016 at 10:32:45AM +0100, Ingo Molnar wrote: > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 969e6704c3c9..851631899352 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -264,7 +264,7 @@ static void tick_nohz_dep_set_all(unsigned long *dep, > { > unsigned long prev; > > - prev = fetch_or(dep, BIT_MASK(bit)); > + prev = xchg_or(dep, BIT_MASK(bit)); > if (!prev) > tick_nohz_full_kick_all(); > } > @@ -294,7 +294,7 @@ void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit) > > ts = per_cpu_ptr(&tick_cpu_sched, cpu); > > - prev = fetch_or(&ts->tick_dep_mask, BIT_MASK(bit)); > + prev = xchg_or(&ts->tick_dep_mask, BIT_MASK(bit)); > if (!prev) { > preempt_disable(); > /* Perf needs local kick that is NMI safe */ Those should probably also use BIT(), BIT_MASK() is specifically for bitmasks, and should be combined with BIT_WORD().