Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756135AbdDQQ5M (ORCPT ); Mon, 17 Apr 2017 12:57:12 -0400 Received: from mail-pg0-f51.google.com ([74.125.83.51]:32854 "EHLO mail-pg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755880AbdDQQ5G (ORCPT ); Mon, 17 Apr 2017 12:57:06 -0400 Date: Mon, 17 Apr 2017 09:57:04 -0700 From: Matthias Kaehlcke To: Dmitry Torokhov Cc: John Stultz , Thomas Gleixner , "linux-kernel@vger.kernel.org" , Grant Grundler , Greg Hackmann , Michael Davidson Subject: Re: [PATCH] clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK Message-ID: <20170417165704.GO28657@google.com> References: <20170411191705.84616-1-mka@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1215 Lines: 33 Hi Dmitry, El Fri, Apr 14, 2017 at 09:02:03PM -0700 Dmitry Torokhov ha dit: > On Tue, Apr 11, 2017 at 12:17 PM, Matthias Kaehlcke wrote: > > Besides reusing existing code this removes the special case handling > > for 64-bit masks, which causes clang to raise a shift count overflow > > warning due to https://bugs.llvm.org//show_bug.cgi?id=10030. > > > > Suggested-by: Dmitry Torokhov > > Signed-off-by: Matthias Kaehlcke > > --- > > include/linux/clocksource.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h > > index cfc75848a35d..06e604b9e9dc 100644 > > --- a/include/linux/clocksource.h > > +++ b/include/linux/clocksource.h > > @@ -120,7 +120,7 @@ struct clocksource { > > #define CLOCK_SOURCE_RESELECT 0x100 > > > > /* simplify initialization of mask field */ > > -#define CLOCKSOURCE_MASK(bits) (u64)((bits) < 64 ? ((1ULL<<(bits))-1) : -1) > > +#define CLOCKSOURCE_MASK(bits) (u64)GENMASK_ULL((bits) - 1, 0) > > I do not think cast to u64 is needed for GENMASK_ULL. Indeed, it is not needed, I will update the patch Thanks! Matthias