Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754217AbdCFOAm (ORCPT ); Mon, 6 Mar 2017 09:00:42 -0500 Received: from mx2.suse.de ([195.135.220.15]:33422 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754178AbdCFOAX (ORCPT ); Mon, 6 Mar 2017 09:00:23 -0500 Date: Mon, 6 Mar 2017 15:00:02 +0100 From: Borislav Petkov To: hpa@zytor.com Cc: Logan Gunthorpe , Linus Torvalds , Thomas Gleixner , Ingo Molnar , Tony Luck , Al Viro , the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: Question Regarding ERMS memcpy Message-ID: <20170306140002.ilw3bpzpm3xzf5pk@pd.tnic> References: <20170305001447.kcxignj3nsq35vci@pd.tnic> <20170305003349.6kgq4ovj7ipezfxu@pd.tnic> <20170305095059.l4od2yjqm5yxx6ln@pd.tnic> <20170305195432.6occvwaujq3l4ejl@pd.tnic> <5be40886-b468-d828-f948-2ad99b95a230@deltatee.com> <20170306133327.usksddtpum7fftqs@pd.tnic> <86022C23-30AA-4501-ABEE-1154CB4FF61D@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <86022C23-30AA-4501-ABEE-1154CB4FF61D@zytor.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 682 Lines: 24 On Mon, Mar 06, 2017 at 05:41:22AM -0800, hpa@zytor.com wrote: > It isn't really that straightforward IMO. > > For UC memory transaction size really needs to be specified explicitly > at all times and should be part of the API, rather than implicit. > > For WC/WT/WB device memory, the ordinary memcpy is valid and > preferred. I'm practically partially reverting 6175ddf06b61 ("x86: Clean up mem*io functions.") Are you saying, this was wrong before too? Maybe it was wrong, strictly speaking, but maybe that was good enough for our purposes... -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --