From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F09FC433F4 for ; Fri, 31 Aug 2018 19:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D33FA2083B for ; Fri, 31 Aug 2018 19:12:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D33FA2083B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbeHaXVF (ORCPT ); Fri, 31 Aug 2018 19:21:05 -0400 Received: from ale.deltatee.com ([207.54.116.67]:48140 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727201AbeHaXVF (ORCPT ); Fri, 31 Aug 2018 19:21:05 -0400 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1fvopp-0006bO-E0; Fri, 31 Aug 2018 13:11:58 -0600 To: =?UTF-8?Q?Christian_K=c3=b6nig?= , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-block@vger.kernel.org Cc: Stephen Bates , Christoph Hellwig , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , Jonathan Corbet References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-7-logang@deltatee.com> <98bff500-4e4c-3a34-6762-16ef4b076d90@amd.com> <6820d451-9591-1979-00bf-60c65fc4f136@deltatee.com> <30411655-9b90-749e-857f-318dac7cccbf@amd.com> From: Logan Gunthorpe Message-ID: <9452ee6c-e989-d178-cd51-f29782ad9b31@deltatee.com> Date: Fri, 31 Aug 2018 13:11:48 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <30411655-9b90-749e-857f-318dac7cccbf@amd.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: corbet@lwn.net, alex.williamson@redhat.com, benh@kernel.crashing.org, jglisse@redhat.com, dan.j.williams@intel.com, maxg@mellanox.com, jgg@mellanox.com, bhelgaas@google.com, sagi@grimberg.me, keith.busch@intel.com, hch@lst.de, sbates@raithlin.com, linux-block@vger.kernel.org, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, christian.koenig@amd.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v5 06/13] PCI/P2PDMA: Add P2P DMA driver writer's documentation X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 31/08/18 11:38 AM, Christian König wrote: > If you can separate out adding the detection I can take a look adding > this with my DMA-buf P2P efforts. Oh, maybe my previous email wasn't clear, but I'd say that detection is already separate from ZONE_DEVICE. Nothing really needs to be changed. I just think you'll probably want to write you're own function similar to pci_p2pdma_distance that perhaps just takes two pci_devs instead of the list of clients as is needed by nvme-of-like users. To enable a whitelist we just have to handle the case where upstream_bridge_distance() returns -1 and check if the devices are in the same root complex with supported root ports before deciding the transaction is not supported. Logan