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[73.158.218.242]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-2446cb0dd5bsm16573385ad.63.2025.08.15.08.31.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Aug 2025 08:31:06 -0700 (PDT) Date: Fri, 15 Aug 2025 08:31:05 -0700 From: Stanislav Fomichev To: Dragos Tatulea Cc: almasrymina@google.com, asml.silence@gmail.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jens Axboe , Saeed Mahameed , Tariq Toukan , Mark Bloch , Leon Romanovsky , Andrew Lunn , cratiu@nvidia.com, parav@nvidia.com, Christoph Hellwig , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [RFC net-next v3 0/7] devmem/io_uring: allow more flexibility for ZC DMA devices Message-ID: References: <20250815110401.2254214-2-dtatulea@nvidia.com> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250815110401.2254214-2-dtatulea@nvidia.com> On 08/15, Dragos Tatulea wrote: > For TCP zerocopy rx (io_uring, devmem), there is an assumption that the > parent device can do DMA. However that is not always the case: > - Scalable Function netdevs [1] have the DMA device in the grandparent. > - For Multi-PF netdevs [2] queues can be associated to different DMA > devices. > > The series adds an API for getting the DMA device for a netdev queue. > Drivers that have special requirements can implement the newly added > queue management op. Otherwise the parent will still be used as before. > > This series continues with switching to this API for io_uring zcrx and > devmem and adds a ndo_queue_dma_dev op for mlx5. > > The last part of the series changes devmem rx bind to get the DMA device > per queue and blocks the case when multiple queues use different DMA > devices. The tx bind is left as is. > > [1] Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst > [2] Documentation/networking/multi-pf-netdev.rst > > Signed-off-by: Dragos Tatulea > > ---- > Changes sice v2 [3]: > - Downgraded to RFC status until consensus is reached. > - Implemented more generic approach as discussed during > v2 review. > - Refactor devmem to get DMA device for multiple rx queues for > multi PF netdev support. > - Renamed series with a more generic name. > > Changes since v1 [2]: > - Dropped the Fixes tag. > - Added more documentation as requeseted. > - Renamed the patch title to better reflect its purpose. > > Changes since RFC [1]: > - Upgraded from RFC status. > - Dropped driver specific bits for generic solution. > - Implemented single patch as a fix as requested in RFC. > - Handling of multi-PF netdevs will be handled in a subsequent patch > series. > > [1] RFC: https://lore.kernel.org/all/20250702172433.1738947-2-dtatulea@nvidia.com/ > [2] v1: https://lore.kernel.org/all/20250709124059.516095-2-dtatulea@nvidia.com/ > [3] v2: https://lore.kernel.org/all/20250711092634.2733340-2-dtatulea@nvidia.com/ > --- > Dragos Tatulea (7): > queue_api: add support for fetching per queue DMA dev [..] > io_uring/zcrx: add support for custom DMA devices Did something happen to 2/7? I don't see it in my mailbox and in the lore..