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linux/net/core/netdev_queues.c

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queue_api: add support for fetching per queue DMA dev For zerocopy (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. This patch introduces the a queue based interface for allowing drivers to expose a different DMA device for zerocopy. [1] Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst [2] Documentation/networking/multi-pf-netdev.rst Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-3-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:55 +03:00
net: Implement netdev_nl_queue_create_doit Implement netdev_nl_queue_create_doit which creates a new rx queue in a virtual netdev and then leases it to a rx queue in a physical netdev. Example with ynl client: # ynl --family netdev --output-json --do queue-create \ --json '{"ifindex": 8, "type": "rx", "lease": {"ifindex": 4, "queue": {"type": "rx", "id": 15}}}' {'id': 1} Note that the netdevice locking order is always from the virtual to the physical device. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Co-developed-by: David Wei <dw@davidwei.uk> Signed-off-by: David Wei <dw@davidwei.uk> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-3-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:19 +02:00
queue_api: add support for fetching per queue DMA dev For zerocopy (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. This patch introduces the a queue based interface for allowing drivers to expose a different DMA device for zerocopy. [1] Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst [2] Documentation/networking/multi-pf-netdev.rst Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-3-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:55 +03:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
queue_api: add support for fetching per queue DMA dev For zerocopy (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. This patch introduces the a queue based interface for allowing drivers to expose a different DMA device for zerocopy. [1] Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst [2] Documentation/networking/multi-pf-netdev.rst Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-3-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:55 +03:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
net: remove the netif_get_rx_queue_lease_locked() helpers The netif_get_rx_queue_lease_locked() API hides the locking and the descend onto the leased queue. Making the code harder to follow (at least to me). Remove the API and open code the descend a bit. Most of the code now looks like: if (!leased) return __helper(x); hw_rxq = .. netdev_lock(hw_rxq->dev); ret = __helper(x); netdev_unlock(hw_rxq->dev); return ret; Of course if we have more code paths that need the wrapping we may need to revisit. For now, IMHO, having to know what netif_get_rx_queue_lease_locked() does is not worth the 20LoC it saves. Link: https://patch.msgid.link/20260408151251.72bd2482@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-08 15:12:51 -07:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
net: expect instance lock in netdev_queue_get_dma_dev() netdev_queue_get_dma_dev() uses "compat" locking assert which wants either the rtnl_lock or netdev instance lock. This is not right, the callers are taking the instance lock unconditionally. All entry points for queue config are purely instance locked. In other words the callers use netdev_get_by_index_lock(), not netdev_get_by_index_lock_ops_compat(). All the state we will access is effectively instance lock protected (it's const for devices which are not ops-locked). Update the assert to avoid false positive warnings. Cc: stable@vger.kernel.org Fixes: b6c5f9454ef34 ("io_uring/zcrx: call netdev_queue_get_dma_dev() under instance lock") Reported-by: syzbot+a78926bdac2adb52dc0e@syzkaller.appspotmail.com Reviewed-by: Simon Horman <horms@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://patch.msgid.link/20260806225627.3998672-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-06 15:56:26 -07:00
net: remove the netif_get_rx_queue_lease_locked() helpers The netif_get_rx_queue_lease_locked() API hides the locking and the descend onto the leased queue. Making the code harder to follow (at least to me). Remove the API and open code the descend a bit. Most of the code now looks like: if (!leased) return __helper(x); hw_rxq = .. netdev_lock(hw_rxq->dev); ret = __helper(x); netdev_unlock(hw_rxq->dev); return ret; Of course if we have more code paths that need the wrapping we may need to revisit. For now, IMHO, having to know what netif_get_rx_queue_lease_locked() does is not worth the 20LoC it saves. Link: https://patch.msgid.link/20260408151251.72bd2482@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-08 15:12:51 -07:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
net: remove the netif_get_rx_queue_lease_locked() helpers The netif_get_rx_queue_lease_locked() API hides the locking and the descend onto the leased queue. Making the code harder to follow (at least to me). Remove the API and open code the descend a bit. Most of the code now looks like: if (!leased) return __helper(x); hw_rxq = .. netdev_lock(hw_rxq->dev); ret = __helper(x); netdev_unlock(hw_rxq->dev); return ret; Of course if we have more code paths that need the wrapping we may need to revisit. For now, IMHO, having to know what netif_get_rx_queue_lease_locked() does is not worth the 20LoC it saves. Link: https://patch.msgid.link/20260408151251.72bd2482@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-08 15:12:51 -07:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
net: remove the netif_get_rx_queue_lease_locked() helpers The netif_get_rx_queue_lease_locked() API hides the locking and the descend onto the leased queue. Making the code harder to follow (at least to me). Remove the API and open code the descend a bit. Most of the code now looks like: if (!leased) return __helper(x); hw_rxq = .. netdev_lock(hw_rxq->dev); ret = __helper(x); netdev_unlock(hw_rxq->dev); return ret; Of course if we have more code paths that need the wrapping we may need to revisit. For now, IMHO, having to know what netif_get_rx_queue_lease_locked() does is not worth the 20LoC it saves. Link: https://patch.msgid.link/20260408151251.72bd2482@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-08 15:12:51 -07:00
net: Proxy netdev_queue_get_dma_dev for leased queues Extend netdev_queue_get_dma_dev to return the physical device of the real rxq for DMA in case the queue was leased. This allows memory providers like io_uring zero-copy or devmem to bind to the physically leased rxq via virtual devices such as netkit. Signed-off-by: David Wei <dw@davidwei.uk> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-8-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:24 +02:00
net: Implement netdev_nl_queue_create_doit Implement netdev_nl_queue_create_doit which creates a new rx queue in a virtual netdev and then leases it to a rx queue in a physical netdev. Example with ynl client: # ynl --family netdev --output-json --do queue-create \ --json '{"ifindex": 8, "type": "rx", "lease": {"ifindex": 4, "queue": {"type": "rx", "id": 15}}}' {'id': 1} Note that the netdevice locking order is always from the virtual to the physical device. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Co-developed-by: David Wei <dw@davidwei.uk> Signed-off-by: David Wei <dw@davidwei.uk> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260402231031.447597-3-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-03 01:10:19 +02:00