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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-502a1d9ee19sm71855641cf.14.2026.01.19.08.46.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jan 2026 08:46:20 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vhsOR-00000005IML-2VzR; Mon, 19 Jan 2026 12:46:19 -0400 Date: Mon, 19 Jan 2026 12:46:19 -0400 From: Jason Gunthorpe To: Thomas =?utf-8?Q?Hellstr=C3=B6m?= Cc: Leon Romanovsky , Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , Alex Deucher , David Airlie , Simona Vetter , Gerd Hoffmann , Dmitry Osipenko , Gurchetan Singh , Chia-I Wu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lucas De Marchi , Rodrigo Vivi , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, virtualization@lists.linux.dev, intel-xe@lists.freedesktop.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, kvm@vger.kernel.org Subject: Re: [PATCH v2 2/4] dma-buf: Document revoke semantics Message-ID: <20260119164619.GG961572@ziepe.ca> References: <20260118-dmabuf-revoke-v2-0-a03bb27c0875@nvidia.com> <20260118-dmabuf-revoke-v2-2-a03bb27c0875@nvidia.com> <8bc75706c18c410f9564805c487907aba0aab627.camel@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8bc75706c18c410f9564805c487907aba0aab627.camel@linux.intel.com> On Sun, Jan 18, 2026 at 03:29:02PM +0100, Thomas Hellström wrote: > Why would the importer want to verify the exporter's support for > revocation? If the exporter doesn't support it, the only consequence > would be that invalidate_mappings() would never be called, and that > dma_buf_pin() is a NOP. Besides, dma_buf_pin() would not return an > error if the exporter doesn't implement the pin() callback? I think the comment and commit message should be clarified that dma_buf_attachment_is_revoke() is called by the exporter. The purpose is for the exporter that wants to call move_notify() on a pinned DMABUF to determine if the importer is going to support it. Jason