From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C421C25B47 for ; Wed, 25 Oct 2023 10:30:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234771AbjJYKaa (ORCPT ); Wed, 25 Oct 2023 06:30:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232584AbjJYKa3 (ORCPT ); Wed, 25 Oct 2023 06:30:29 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B44D4BB; Wed, 25 Oct 2023 03:30:26 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ED2332F4; Wed, 25 Oct 2023 03:31:07 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.69.205]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F31B23F738; Wed, 25 Oct 2023 03:30:24 -0700 (PDT) Date: Wed, 25 Oct 2023 11:30:20 +0100 From: Mark Rutland To: Masami Hiramatsu Cc: Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "wuqiang . matt" , Peter Zijlstra , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH] locking/atomic: sh: Use generic_cmpxchg_local for arch_cmpxchg_local() Message-ID: References: <169815917362.8695.13904684741526725648.stgit@devnote2> <20231025084255.bc70b9d0e5af9f6f3d2d4735@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231025084255.bc70b9d0e5af9f6f3d2d4735@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Wed, Oct 25, 2023 at 08:42:55AM +0900, Masami Hiramatsu wrote: > On Tue, 24 Oct 2023 16:08:12 +0100 > Mark Rutland wrote: > > > On Tue, Oct 24, 2023 at 11:52:54PM +0900, Masami Hiramatsu (Google) wrote: > > > From: Masami Hiramatsu (Google) > > > > > > Use generic_cmpxchg_local() for arch_cmpxchg_local() implementation > > > in SH architecture because it does not implement arch_cmpxchg_local(). > > > > I do not think this is correct. > > > > The implementation in is UP-only (and it only > > disables interrupts), whereas arch/sh can be built SMP. We should probably add > > some guards into for that as we have in > > . > > Isn't cmpxchg_local for the data which only needs to ensure to do cmpxchg > on local CPU? > So I think it doesn't care about the other CPUs (IOW, it should not touched by > other CPUs), so it only considers UP case. E.g. on x86, arch_cmpxchg_local() is > defined as raw "cmpxchg" without lock prefix. > > #define __cmpxchg_local(ptr, old, new, size) \ > __raw_cmpxchg((ptr), (old), (new), (size), "") > Yes, you're right; sorry for the noise. For your original patch: Acked-by: Mark Rutland Mark. > > Thank you, > > > > > > I think the right thing to do here is to define arch_cmpxchg_local() in terms > > of arch_cmpxchg(), i.e. at the bottom of arch/sh's add: > > > > #define arch_cmpxchg_local arch_cmpxchg > > > > Mark. > > > > > > > > Reported-by: kernel test robot > > > Closes: https://lore.kernel.org/oe-kbuild-all/202310241310.Ir5uukOG-lkp@intel.com/ > > > Signed-off-by: Masami Hiramatsu (Google) > > > --- > > > arch/sh/include/asm/cmpxchg.h | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h > > > index 288f6f38d98f..e920e61fb817 100644 > > > --- a/arch/sh/include/asm/cmpxchg.h > > > +++ b/arch/sh/include/asm/cmpxchg.h > > > @@ -71,4 +71,6 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old, > > > (unsigned long)_n_, sizeof(*(ptr))); \ > > > }) > > > > > > +#include > > > + > > > #endif /* __ASM_SH_CMPXCHG_H */ > > > > > > -- > Masami Hiramatsu (Google)