Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753835AbcLFQjM (ORCPT ); Tue, 6 Dec 2016 11:39:12 -0500 Received: from quartz.orcorp.ca ([184.70.90.242]:55287 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753761AbcLFQjI (ORCPT ); Tue, 6 Dec 2016 11:39:08 -0500 Date: Tue, 6 Dec 2016 09:38:50 -0700 From: Jason Gunthorpe To: Stephen Bates Cc: Dan Williams , Logan Gunthorpe , Haggai Eran , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@ml01.01.org" , "christian.koenig@amd.com" , "Suravee.Suthikulpanit@amd.com" , "John.Bridgman@amd.com" , "Alexander.Deucher@amd.com" , "Linux-media@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Max Gurtovoy , "linux-pci@vger.kernel.org" , "serguei.sagalovitch@amd.com" , "Paul.Blinzer@amd.com" , "Felix.Kuehling@amd.com" , "ben.sander@amd.com" Subject: Re: Enabling peer to peer device transactions for PCIe devices Message-ID: <20161206163850.GC28066@obsidianresearch.com> References: <5f5b7989-84f5-737e-47c8-831f752d6280@deltatee.com> <61a2fb07344aacd81111449d222de66e.squirrel@webmail.raithlin.com> <20161205171830.GB27784@obsidianresearch.com> <20161205180231.GA28133@obsidianresearch.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.156 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 591 Lines: 12 > > I'm not opposed to mapping /dev/nvmeX. However, the lookup is trivial > > to accomplish in sysfs through /sys/dev/char to find the sysfs path of the > > device-dax instance under the nvme device, or if you already have the nvme > > sysfs path the dax instance(s) will appear under the "dax" sub-directory. > > Personally I think mapping the dax resource in the sysfs tree is a nice > way to do this and a bit more intuitive than mapping a /dev/nvmeX. It is still not at all clear to me what userpsace is supposed to do with this on nvme.. How is the CMB usable from userspace? Jason