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[207.54.116.67]) by mx.google.com with ESMTPS id m28si2583869jal.16.2019.01.29.12.43.15 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 29 Jan 2019 12:43:15 -0800 (PST) Received-SPF: pass (google.com: domain of logang@deltatee.com designates 207.54.116.67 as permitted sender) client-ip=207.54.116.67; Authentication-Results: mx.google.com; spf=pass (google.com: domain of logang@deltatee.com designates 207.54.116.67 as permitted sender) smtp.mailfrom=logang@deltatee.com Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1goaDn-0006jl-FD; Tue, 29 Jan 2019 13:43:04 -0700 To: Jerome Glisse Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , "Rafael J . Wysocki" , Bjorn Helgaas , Christian Koenig , Felix Kuehling , Jason Gunthorpe , linux-pci@vger.kernel.org, dri-devel@lists.freedesktop.org, Christoph Hellwig , Marek Szyprowski , Robin Murphy , Joerg Roedel , iommu@lists.linux-foundation.org References: <20190129174728.6430-1-jglisse@redhat.com> <20190129174728.6430-4-jglisse@redhat.com> <20190129191120.GE3176@redhat.com> <20190129194418.GG3176@redhat.com> From: Logan Gunthorpe Message-ID: Date: Tue, 29 Jan 2019 13:43:02 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190129194418.GG3176@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: iommu@lists.linux-foundation.org, jroedel@suse.de, robin.murphy@arm.com, m.szyprowski@samsung.com, hch@lst.de, dri-devel@lists.freedesktop.org, linux-pci@vger.kernel.org, jgg@mellanox.com, Felix.Kuehling@amd.com, christian.koenig@amd.com, bhelgaas@google.com, rafael@kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, jglisse@redhat.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [RFC PATCH 3/5] mm/vma: add support for peer to peer to device vma 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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2019-01-29 12:44 p.m., Jerome Glisse wrote: >> I'd suggest [1] should be a part of the patchset so we can actually see >> a user of the stuff you're adding. > > I did not wanted to clutter patchset with device driver specific usage > of this. As the API can be reason about in abstract way. It's hard to reason about an interface when you can't see what all the layers want to do with it. Most maintainers (I'd hope) would certainly never merge code that has no callers, and for much the same reason, I'd rather not review patches that don't have real use case examples. Logan