Path: csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod From: Borislav Petkov Newsgroups: linux.kernel Subject: Re: Question Regarding ERMS memcpy Date: Mon, 06 Mar 2017 15:10:04 +0100 Message-ID: References: X-Original-To: hpa@zytor.com MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: NeoMutt/20170113 (1.7.2) Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 24 Organization: linux.* mail to news gateway X-Original-Cc: Logan Gunthorpe , Linus Torvalds , Thomas Gleixner , Ingo Molnar , Tony Luck , Al Viro , the arch/x86 maintainers , Linux Kernel Mailing List X-Original-Date: Mon, 6 Mar 2017 15:00:02 +0100 X-Original-Message-ID: <20170306140002.ilw3bpzpm3xzf5pk@pd.tnic> X-Original-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> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1593384 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) --