From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751982AbeEBP4y (ORCPT ); Wed, 2 May 2018 11:56:54 -0400 Received: from ale.deltatee.com ([207.54.116.67]:46764 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750954AbeEBP4u (ORCPT ); Wed, 2 May 2018 11:56:50 -0400 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 , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson References: <20180423233046.21476-1-logang@deltatee.com> From: Logan Gunthorpe Message-ID: <805645c1-ea40-2e57-88eb-5dd34e579b2e@deltatee.com> Date: Wed, 2 May 2018 09:56:09 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: 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, axboe@kernel.dk, 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 v4 00/14] Copy Offload in NVMe Fabrics with P2P PCI Memory 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christian, On 5/2/2018 5:51 AM, Christian König wrote: > it would be rather nice to have if you could separate out the functions > to detect if peer2peer is possible between two devices. This would essentially be pci_p2pdma_distance() in the existing patchset. It returns the sum of the distance between a list of clients and a P2PDMA provider. It returns -1 if peer2peer is not possible between the devices (presently this means they are not behind the same root port). Logan