From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757498AbcEEQ3g (ORCPT ); Thu, 5 May 2016 12:29:36 -0400 Received: from mout.kundenserver.de ([217.72.192.75]:50694 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756016AbcEEQ3d convert rfc822-to-8bit (ORCPT ); Thu, 5 May 2016 12:29:33 -0400 From: Arnd Bergmann To: Horia =?utf-8?B?R2VhbnTEgw==?= Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/8] asm-generic/io.h: allow barriers in io{read,write}{16,32}be Date: Thu, 05 May 2016 18:29:27 +0200 Message-ID: <4160174.j7y8ElCmf4@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1462462545-27637-1-git-send-email-horia.geanta@nxp.com> References: <1462462435-27403-1-git-send-email-horia.geanta@nxp.com> <1462462545-27637-1-git-send-email-horia.geanta@nxp.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="utf-8" X-Provags-ID: V03:K0:QztPs14IEcMTyJdjRxo2Rwq+EpHhyfdSsidx/PIGLn3CyxA8rde Ft6IYVpEznzcPBdwVNjB5Z6FknKjFbMig2XK150zm4Is/nEw8QfhR8BHNm6d5r8wdxmDcF/ i63ys+0899OrQ0RsphAMXY3sOWyRwJZch02NyI1P3gpzib/05egvU2y+iDqtAX1eyAWR71s fseT9Q+Z9V259w19WKXVA== X-UI-Out-Filterresults: notjunk:1;V01:K0:3OZ/vBpCu7I=:Tmqa+jg4rJYtcnDpWqVKOu lZyHxh4d60v8gbvowRFJgqrzcDTvuopF2leQKcIr+esN8V/SSCsZfn5ZyOJz+JTRjNxou0PUT xj3RNB0QTAMX9LU7Srx1HQsZFpjFl2ebWUOR5+NFTP1ULxPJiQJV+lTAdsiOz/9lgjtL6disa 7o3hQh3acXikIssfJygIgqO7RGvQYTez1Zi8cUgDQBX9skRQUXIV/2IqOiOfMw9DsomldcKYt 0mn7YYSlnnctGwrF9LNFjY+Me0wvFT35xxZMTkXu6HfIaCz9eyQCHMBtY3yP+eNiIEGKEl/kT kJi9D/tijHJY/PjG8zP2rj9e+X7GYAOpbN2P/gQRwriZWa1t/OVmsqTyI5/2OzALRyCBLw7XX LBtIaCNu9rKM1MwTvuYbZo5bCCt3VSl7dbDhtnA8mZXxi8snwCkQBDisuAc4laxzq6J8RTwRW a6r8JpvAdY0zXL9pRe4pkvd7CBcnkFzPvO1lLFtRDADIgEGsqqmWwhfzjb1opYixhE07bkH+T Fdz1CWBR3Y6GLgBFGe0nBNi1ZHJ0iUr5kycd93fg32yhgglvCALR28xg5EmzkGzIZ7Ik2lxdf dqBxL8nHw+DBZJkGW3FG5S5/EnjXtRV+l3Fuwur20MSBgnZmQwlSwm2MCQsHRtBsQImtvY0BE PNN7eVxO8BPmHX6GgvA82GE3b6BEoiezth3AO27kVhXGFHp3M0LKWlA3uuwgFh1EK/NO/HE7a VJez4s0Yvr44O/Qd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 05 May 2016 18:35:45 Horia Geantă wrote: > While reviewing the addition of io{read,write}64be accessors, Arnd > > -finds a potential problem: > "If an architecture overrides readq/writeq to have barriers but does > not override ioread64be/iowrite64be, this will lack the barriers and > behave differently from the little-endian version. I think the only > affected architecture is ARC, since ARM and ARM64 both override the > big-endian accessors to have the correct barriers, and all others > don't use barriers at all." > > -suggests a fix for the same problem in existing code (16/32-bit > accessors); the fix leads "to a double-swap on architectures that > don't override the io{read,write}{16,32}be accessors, but it will > work correctly on all architectures without them having to override > these accessors." > > Suggested-by: Arnd Bergmann > Signed-off-by: Horia Geantă > --- Acked-by: Arnd Bergmann