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linux/net/core/devmem.c

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netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: page_pool: create hooks for custom memory providers A spin off from the original page pool memory providers patch by Jakub, which allows extending page pools with custom allocators. One of such providers is devmem TCP, and the other is io_uring zerocopy added in following patches. Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/ Co-developed-by: Jakub Kicinski <kuba@kernel.org> # initial mp proposal Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:15 -08:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
memory-provider: dmabuf devmem memory provider Implement a memory provider that allocates dmabuf devmem in the form of net_iov. The provider receives a reference to the struct netdev_dmabuf_binding via the pool->mp_priv pointer. The driver needs to set this pointer for the provider in the net_iov. The provider obtains a reference on the netdev_dmabuf_binding which guarantees the binding and the underlying mapping remains alive until the provider is destroyed. Usage of PP_FLAG_DMA_MAP is required for this memory provide such that the page_pool can provide the driver with the dma-addrs of the devmem. Support for PP_FLAG_DMA_SYNC_DEV is omitted for simplicity & p.order != 0. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-7-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:50 +00:00
page_pool: devmem support Convert netmem to be a union of struct page and struct netmem. Overload the LSB of struct netmem* to indicate that it's a net_iov, otherwise it's a page. Currently these entries in struct page are rented by the page_pool and used exclusively by the net stack: struct { unsigned long pp_magic; struct page_pool *pp; unsigned long _pp_mapping_pad; unsigned long dma_addr; atomic_long_t pp_ref_count; }; Mirror these (and only these) entries into struct net_iov and implement netmem helpers that can access these common fields regardless of whether the underlying type is page or net_iov. Implement checks for net_iov in netmem helpers which delegate to mm APIs, to ensure net_iov are never passed to the mm stack. Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-6-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:49 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: page_pool: create hooks for custom memory providers A spin off from the original page pool memory providers patch by Jakub, which allows extending page pools with custom allocators. One of such providers is devmem TCP, and the other is io_uring zerocopy added in following patches. Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/ Co-developed-by: Jakub Kicinski <kuba@kernel.org> # initial mp proposal Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:15 -08:00
net: prepare for non devmem TCP memory providers There is a good bunch of places in generic paths assuming that the only page pool memory provider is devmem TCP. As we want to reuse the net_iov and provider infrastructure, we need to patch it up and explicitly check the provider type when we branch into devmem TCP code. Reviewed-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-9-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:19 -08:00
netmem: add niov->type attribute to distinguish different net_iov types Later patches in the series adds TX net_iovs where there is no pp associated, so we can't rely on niov->pp->mp_ops to tell what is the type of the net_iov. Add a type enum to the net_iov which tells us the net_iov type. Signed-off-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250508004830.4100853-2-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:21 +00:00
net: prepare for non devmem TCP memory providers There is a good bunch of places in generic paths assuming that the only page pool memory provider is devmem TCP. As we want to reuse the net_iov and provider infrastructure, we need to patch it up and explicitly check the provider type when we branch into devmem TCP code. Reviewed-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-9-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:19 -08:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: fix DMA direction on unmapping Looks like we always unmap the DMA_BUF with DMA_FROM_DEVICE direction. While at it unexport __net_devmem_dmabuf_binding_free(), it's internal. Found by code inspection. Fixes: bd61848900bf ("net: devmem: Implement TX path") Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250801011335.2267515-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-31 18:13:35 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
page_pool: devmem support Convert netmem to be a union of struct page and struct netmem. Overload the LSB of struct netmem* to indicate that it's a net_iov, otherwise it's a page. Currently these entries in struct page are rented by the page_pool and used exclusively by the net stack: struct { unsigned long pp_magic; struct page_pool *pp; unsigned long _pp_mapping_pad; unsigned long dma_addr; atomic_long_t pp_ref_count; }; Mirror these (and only these) entries into struct net_iov and implement netmem helpers that can access these common fields regardless of whether the underlying type is page or net_iov. Implement checks for net_iov in netmem helpers which delegate to mm APIs, to ensure net_iov are never passed to the mm stack. Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-6-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:49 +00:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
net: prefix devmem specific helpers Add prefixes to all helpers that are specific to devmem TCP, i.e. net_iov_binding[_id]. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-3-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:13 -08:00
netdev: netdevice devmem allocator Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:48 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: avoid false positive warnings in __net_mp_close_rxq() Commit under Fixes solved the problem of spurious warnings when we uninstall an MP from a device while its down. The __net_mp_close_rxq() which is used by io_uring was not fixed. Move the fix over and reuse __net_mp_close_rxq() in the devmem path. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: a70f891e0fa0 ("net: devmem: do not WARN conditionally after netdev_rx_queue_restart()") Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250403013405.2827250-3-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:05 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: avoid false positive warnings in __net_mp_close_rxq() Commit under Fixes solved the problem of spurious warnings when we uninstall an MP from a device while its down. The __net_mp_close_rxq() which is used by io_uring was not fixed. Move the fix over and reuse __net_mp_close_rxq() in the devmem path. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: a70f891e0fa0 ("net: devmem: do not WARN conditionally after netdev_rx_queue_restart()") Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250403013405.2827250-3-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:05 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: move mp dev config validation to __net_mp_open_rxq() devmem code performs a number of safety checks to avoid having to reimplement all of them in the drivers. Move those to __net_mp_open_rxq() and reuse that function for binding to make sure that io_uring ZC also benefits from them. While at it rename the queue ID variable to rxq_idx in __net_mp_open_rxq(), we touch most of the relevant lines. The XArray insertion is reordered after the netdev_rx_queue_restart() call, otherwise we'd need to duplicate the queue index check or risk inserting an invalid pointer. The XArray allocation failures should be extremely rare. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: 6e18ed929d3b ("net: add helpers for setting a memory provider on an rx queue") Link: https://patch.msgid.link/20250403013405.2827250-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:04 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: move mp dev config validation to __net_mp_open_rxq() devmem code performs a number of safety checks to avoid having to reimplement all of them in the drivers. Move those to __net_mp_open_rxq() and reuse that function for binding to make sure that io_uring ZC also benefits from them. While at it rename the queue ID variable to rxq_idx in __net_mp_open_rxq(), we touch most of the relevant lines. The XArray insertion is reordered after the netdev_rx_queue_restart() call, otherwise we'd need to duplicate the queue index check or risk inserting an invalid pointer. The XArray allocation failures should be extremely rare. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: 6e18ed929d3b ("net: add helpers for setting a memory provider on an rx queue") Link: https://patch.msgid.link/20250403013405.2827250-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:04 -07:00
net: devmem: add ring parameter filtering If driver doesn't support ring parameter or tcp-data-split configuration is not sufficient, the devmem should not be set up. Before setup the devmem, tcp-data-split should be ON and hds-thresh value should be 0. Tested-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Taehee Yoo <ap420073@gmail.com> Link: https://patch.msgid.link/20250114142852.3364986-4-ap420073@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-14 14:28:45 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: move mp dev config validation to __net_mp_open_rxq() devmem code performs a number of safety checks to avoid having to reimplement all of them in the drivers. Move those to __net_mp_open_rxq() and reuse that function for binding to make sure that io_uring ZC also benefits from them. While at it rename the queue ID variable to rxq_idx in __net_mp_open_rxq(), we touch most of the relevant lines. The XArray insertion is reordered after the netdev_rx_queue_restart() call, otherwise we'd need to duplicate the queue index check or risk inserting an invalid pointer. The XArray allocation failures should be extremely rare. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: 6e18ed929d3b ("net: add helpers for setting a memory provider on an rx queue") Link: https://patch.msgid.link/20250403013405.2827250-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:04 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: move mp dev config validation to __net_mp_open_rxq() devmem code performs a number of safety checks to avoid having to reimplement all of them in the drivers. Move those to __net_mp_open_rxq() and reuse that function for binding to make sure that io_uring ZC also benefits from them. While at it rename the queue ID variable to rxq_idx in __net_mp_open_rxq(), we touch most of the relevant lines. The XArray insertion is reordered after the netdev_rx_queue_restart() call, otherwise we'd need to duplicate the queue index check or risk inserting an invalid pointer. The XArray allocation failures should be extremely rare. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Fixes: 6e18ed929d3b ("net: add helpers for setting a memory provider on an rx queue") Link: https://patch.msgid.link/20250403013405.2827250-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-02 18:34:04 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: pull out dma_dev out of net_devmem_bind_dmabuf Fetch the DMA device before calling net_devmem_bind_dmabuf() and pass it on as a parameter. This is needed for an upcoming change which will read the DMA device per queue. This patch has no functional changes. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-7-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:59 +03:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: move list_add to net_devmem_bind_dmabuf. It's annoying for the list_add to be outside net_devmem_bind_dmabuf, but the list_del is in net_devmem_unbind_dmabuf. Make it consistent by having both the list_add/del be inside the net_devmem_[un]bind_dmabuf. Cc: ap420073@gmail.com Signed-off-by: Mina Almasry <almasrymina@google.com> Tested-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250523230524.1107879-2-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-23 23:05:17 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: get netdev DMA device via new API Switch to the new API for fetching DMA devices for a netdev. The API is called with queue index 0 for now which is equivalent with the previous behavior. This patch will allow devmem to work with devices where the DMA device is not stored in the parent device. mlx5 SFs are an example of such a device. Multi-PF netdevs are still problematic (as they were before this change). Upcoming patches will address this for the rx binding. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-5-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:57 +03:00
net: devmem: pull out dma_dev out of net_devmem_bind_dmabuf Fetch the DMA device before calling net_devmem_bind_dmabuf() and pass it on as a parameter. This is needed for an upcoming change which will read the DMA device per queue. This patch has no functional changes. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-7-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:59 +03:00
net: devmem: get netdev DMA device via new API Switch to the new API for fetching DMA devices for a netdev. The API is called with queue index 0 for now which is equivalent with the previous behavior. This patch will allow devmem to work with devices where the DMA device is not stored in the parent device. mlx5 SFs are an example of such a device. Multi-PF netdevs are still problematic (as they were before this change). Upcoming patches will address this for the rx binding. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-5-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:57 +03:00
net: devmem: pull out dma_dev out of net_devmem_bind_dmabuf Fetch the DMA device before calling net_devmem_bind_dmabuf() and pass it on as a parameter. This is needed for an upcoming change which will read the DMA device per queue. This patch has no functional changes. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-7-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:59 +03:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: fix kernel panic when netlink socket close after module unload Kernel panic occurs when a devmem TCP socket is closed after NIC module is unloaded. This is Devmem TCP unregistration scenarios. number is an order. (a)netlink socket close (b)pp destroy (c)uninstall result 1 2 3 OK 1 3 2 (d)Impossible 2 1 3 OK 3 1 2 (e)Kernel panic 2 3 1 (d)Impossible 3 2 1 (d)Impossible (a) netdev_nl_sock_priv_destroy() is called when devmem TCP socket is closed. (b) page_pool_destroy() is called when the interface is down. (c) mp_ops->uninstall() is called when an interface is unregistered. (d) There is no scenario in mp_ops->uninstall() is called before page_pool_destroy(). Because unregister_netdevice_many_notify() closes interfaces first and then calls mp_ops->uninstall(). (e) netdev_nl_sock_priv_destroy() accesses struct net_device to acquire netdev_lock(). But if the interface module has already been removed, net_device pointer is invalid, so it causes kernel panic. In summary, there are only 3 possible scenarios. A. sk close -> pp destroy -> uninstall. B. pp destroy -> sk close -> uninstall. C. pp destroy -> uninstall -> sk close. Case C is a kernel panic scenario. In order to fix this problem, It makes mp_dmabuf_devmem_uninstall() set binding->dev to NULL. It indicates an bound net_device was unregistered. It makes netdev_nl_sock_priv_destroy() do not acquire netdev_lock() if binding->dev is NULL. A new binding->lock is added to protect a dev of a binding. So, lock ordering is like below. priv->lock netdev_lock(dev) binding->lock Tests: Scenario A: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 kill $pid ip link set $interface down modprobe -rv $module Scenario B: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 ip link set $interface down kill $pid modprobe -rv $module Scenario C: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 modprobe -rv $module sleep 5 kill $pid Splat looks like: Oops: general protection fault, probably for non-canonical address 0xdffffc001fffa9f7: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI KASAN: probably user-memory-access in range [0x00000000fffd4fb8-0x00000000fffd4fbf] CPU: 0 UID: 0 PID: 2041 Comm: ncdevmem Tainted: G B W 6.15.0-rc1+ #2 PREEMPT(undef) 0947ec89efa0fd68838b78e36aa1617e97ff5d7f Tainted: [B]=BAD_PAGE, [W]=WARN RIP: 0010:__mutex_lock (./include/linux/sched.h:2244 kernel/locking/mutex.c:400 kernel/locking/mutex.c:443 kernel/locking/mutex.c:605 kernel/locking/mutex.c:746) Code: ea 03 80 3c 02 00 0f 85 4f 13 00 00 49 8b 1e 48 83 e3 f8 74 6a 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 34 48 89 fa 48 c1 ea 03 <0f> b6 f RSP: 0018:ffff88826f7ef730 EFLAGS: 00010203 RAX: dffffc0000000000 RBX: 00000000fffd4f88 RCX: ffffffffaa9bc811 RDX: 000000001fffa9f7 RSI: 0000000000000008 RDI: 00000000fffd4fbc RBP: ffff88826f7ef8b0 R08: 0000000000000000 R09: ffffed103e6aa1a4 R10: 0000000000000007 R11: ffff88826f7ef442 R12: fffffbfff669f65e R13: ffff88812a830040 R14: ffff8881f3550d20 R15: 00000000fffd4f88 FS: 0000000000000000(0000) GS:ffff888866c05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563bed0cb288 CR3: 00000001a7c98000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <TASK> ... netdev_nl_sock_priv_destroy (net/core/netdev-genl.c:953 (discriminator 3)) genl_release (net/netlink/genetlink.c:653 net/netlink/genetlink.c:694 net/netlink/genetlink.c:705) ... netlink_release (net/netlink/af_netlink.c:737) ... __sock_release (net/socket.c:647) sock_close (net/socket.c:1393) Fixes: 1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250514154028.1062909-1-ap420073@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-14 15:40:28 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: fix DMA direction on unmapping Looks like we always unmap the DMA_BUF with DMA_FROM_DEVICE direction. While at it unexport __net_devmem_dmabuf_binding_free(), it's internal. Found by code inspection. Fixes: bd61848900bf ("net: devmem: Implement TX path") Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250801011335.2267515-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-31 18:13:35 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: get netdev DMA device via new API Switch to the new API for fetching DMA devices for a netdev. The API is called with queue index 0 for now which is equivalent with the previous behavior. This patch will allow devmem to work with devices where the DMA device is not stored in the parent device. mlx5 SFs are an example of such a device. Multi-PF netdevs are still problematic (as they were before this change). Upcoming patches will address this for the rx binding. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250827144017.1529208-5-dtatulea@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-27 17:39:57 +03:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
netmem: add niov->type attribute to distinguish different net_iov types Later patches in the series adds TX net_iovs where there is no pp associated, so we can't rely on niov->pp->mp_ops to tell what is the type of the net_iov. Add a type enum to the net_iov which tells us the net_iov type. Signed-off-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250508004830.4100853-2-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:21 +00:00
net: generalise net_iov chunk owners Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner, which serves as a useful abstraction to share data and provide a context. However, it's too devmem specific, and we want to reuse it for other memory providers, and for that we need to decouple net_iov from devmem. Make net_iov to point to a new base structure called net_iov_area, which dmabuf_genpool_chunk_owner extends. Reviewed-by: Mina Almasry <almasrymina@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:14 -08:00
page_pool: devmem support Convert netmem to be a union of struct page and struct netmem. Overload the LSB of struct netmem* to indicate that it's a net_iov, otherwise it's a page. Currently these entries in struct page are rented by the page_pool and used exclusively by the net stack: struct { unsigned long pp_magic; struct page_pool *pp; unsigned long _pp_mapping_pad; unsigned long dma_addr; atomic_long_t pp_ref_count; }; Mirror these (and only these) entries into struct net_iov and implement netmem helpers that can access these common fields regardless of whether the underlying type is page or net_iov. Implement checks for net_iov in netmem helpers which delegate to mm APIs, to ensure net_iov are never passed to the mm stack. Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-6-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:49 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: move list_add to net_devmem_bind_dmabuf. It's annoying for the list_add to be outside net_devmem_bind_dmabuf, but the list_del is in net_devmem_unbind_dmabuf. Make it consistent by having both the list_add/del be inside the net_devmem_[un]bind_dmabuf. Cc: ap420073@gmail.com Signed-off-by: Mina Almasry <almasrymina@google.com> Tested-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250523230524.1107879-2-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-23 23:05:17 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: fix DMA direction on unmapping Looks like we always unmap the DMA_BUF with DMA_FROM_DEVICE direction. While at it unexport __net_devmem_dmabuf_binding_free(), it's internal. Found by code inspection. Fixes: bd61848900bf ("net: devmem: Implement TX path") Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20250801011335.2267515-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-31 18:13:35 -07:00
netdev: support binding dma-buf to netdevice Add a netdev_dmabuf_binding struct which represents the dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to rx queues on the netdevice. On the binding, the dma_buf_attach & dma_buf_map_attachment will occur. The entries in the sg_table from mapping will be inserted into a genpool to make it ready for allocation. The chunks in the genpool are owned by a dmabuf_chunk_owner struct which holds the dma-buf offset of the base of the chunk and the dma_addr of the chunk. Both are needed to use allocations that come from this chunk. We create a new type that represents an allocation from the genpool: net_iov. We setup the net_iov allocation size in the genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally allocated by the page pool and given to the drivers. The user can unbind the dmabuf from the netdevice by closing the netlink socket that established the binding. We do this so that the binding is automatically unbound even if the userspace process crashes. The binding and unbinding leaves an indicator in struct netdev_rx_queue that the given queue is bound, and the binding is actuated by resetting the rx queue using the queue API. The netdev_dmabuf_binding struct is refcounted, and releases its resources only when all the refs are released. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:47 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: add get_netmem/put_netmem support Currently net_iovs support only pp ref counts, and do not support a page ref equivalent. This is fine for the RX path as net_iovs are used exclusively with the pp and only pp refcounting is needed there. The TX path however does not use pp ref counts, thus, support for get_page/put_page equivalent is needed for netmem. Support get_netmem/put_netmem. Check the type of the netmem before passing it to page or net_iov specific code to obtain a page ref equivalent. For dmabuf net_iovs, we obtain a ref on the underlying binding. This ensures the entire binding doesn't disappear until all the net_iovs have been put_netmem'ed. We do not need to track the refcount of individual dmabuf net_iovs as we don't allocate/free them from a pool similar to what the buddy allocator does for pages. This code is written to be extensible by other net_iov implementers. get_netmem/put_netmem will check the type of the netmem and route it to the correct helper: pages -> [get|put]_page() dmabuf net_iovs -> net_devmem_[get|put]_net_iov() new net_iovs -> new helpers Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-3-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:22 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
net: devmem: refresh devmem TX dst in case of route invalidation The zero-copy Device Memory (Devmem) transmit path relies on the socket's route cache (`dst_entry`) to validate that the packet is being sent via the network device to which the DMA buffer was bound. However, this check incorrectly fails and returns `-ENODEV` if the socket's route cache entry (`dst`) is merely missing or expired (`dst == NULL`). This scenario is observed during network events, such as when flow steering rules are deleted, leading to a temporary route cache invalidation. This patch fixes -ENODEV error for `net_devmem_get_binding()` by doing the following: 1. It attempts to rebuild the route via `rebuild_header()` if the route is initially missing (`dst == NULL`). This allows the TCP/IP stack to recover from transient route cache misses. 2. It uses `rcu_read_lock()` and `dst_dev_rcu()` to safely access the network device pointer (`dst_dev`) from the route, preventing use-after-free conditions if the device is concurrently removed. 3. It maintains the critical safety check by validating that the retrieved destination device (`dst_dev`) is exactly the device registered in the Devmem binding (`binding->dev`). These changes prevent unnecessary ENODEV failures while maintaining the critical safety requirement that the Devmem resources are only used on the bound network device. Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com> Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Vedant Mathur <vedantmathur@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Shivaji Kant <shivajikant@google.com> Link: https://patch.msgid.link/20251029065420.3489943-1-shivajikant@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 06:54:19 +00:00
net: devmem: Implement TX path Augment dmabuf binding to be able to handle TX. Additional to all the RX binding, we also create tx_vec needed for the TX path. Provide API for sendmsg to be able to send dmabufs bound to this device: - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY implementation, while disabling instances where MSG_ZEROCOPY falls back to copying. We additionally pipe the binding down to the new zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems instead of the traditional page netmems. We also special case skb_frag_dma_map to return the dma-address of these dmabuf net_iovs instead of attempting to map pages. The TX path may release the dmabuf in a context where we cannot wait. This happens when the user unbinds a TX dmabuf while there are still references to its netmems in the TX path. In that case, the netmems will be put_netmem'd from a context where we can't unmap the dmabuf, Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd. Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat of the implementation came from devmem TCP RFC v1[1], which included the TX path, but Stan did all the rebasing on top of netmem/net_iov. Cc: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-08 00:48:24 +00:00
memory-provider: dmabuf devmem memory provider Implement a memory provider that allocates dmabuf devmem in the form of net_iov. The provider receives a reference to the struct netdev_dmabuf_binding via the pool->mp_priv pointer. The driver needs to set this pointer for the provider in the net_iov. The provider obtains a reference on the netdev_dmabuf_binding which guarantees the binding and the underlying mapping remains alive until the provider is destroyed. Usage of PP_FLAG_DMA_MAP is required for this memory provide such that the page_pool can provide the driver with the dma-addrs of the devmem. Support for PP_FLAG_DMA_SYNC_DEV is omitted for simplicity & p.order != 0. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-7-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:50 +00:00
page_pool: Set `dma_sync` to false for devmem memory provider Move the `dma_map` and `dma_sync` checks to `page_pool_init` to make them generic. Set dma_sync to false for devmem memory provider because the dma_sync APIs should not be used for dma_buf backed devmem memory provider. Cc: Jason Gunthorpe <jgg@ziepe.ca> Signed-off-by: Samiullah Khawaja <skhawaja@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20241211212033.1684197-4-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-11 21:20:30 +00:00
page_pool: disable sync for cpu for dmabuf memory provider dmabuf dma-addresses should not be dma_sync'd for CPU/device. Typically its the driver responsibility to dma_sync for CPU, but the driver should not dma_sync for CPU if the netmem is actually coming from a dmabuf memory provider. The page_pool already exposes a helper for dma_sync_for_cpu: page_pool_dma_sync_for_cpu. Upgrade this existing helper to handle netmem, and have it skip dma_sync if the memory is from a dmabuf memory provider. Drivers should migrate to using this helper when adding support for netmem. Also minimize the impact on the dma syncing performance for pages. Special case the dma-sync path for pages to not go through the overhead checks for dma-syncing and conversion to netmem. Cc: Alexander Lobakin <aleksander.lobakin@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Signed-off-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20241211212033.1684197-5-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-11 21:20:31 +00:00
memory-provider: dmabuf devmem memory provider Implement a memory provider that allocates dmabuf devmem in the form of net_iov. The provider receives a reference to the struct netdev_dmabuf_binding via the pool->mp_priv pointer. The driver needs to set this pointer for the provider in the net_iov. The provider obtains a reference on the netdev_dmabuf_binding which guarantees the binding and the underlying mapping remains alive until the provider is destroyed. Usage of PP_FLAG_DMA_MAP is required for this memory provide such that the page_pool can provide the driver with the dma-addrs of the devmem. Support for PP_FLAG_DMA_SYNC_DEV is omitted for simplicity & p.order != 0. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-7-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-10 17:14:50 +00:00
net: page_pool: create hooks for custom memory providers A spin off from the original page pool memory providers patch by Jakub, which allows extending page pools with custom allocators. One of such providers is devmem TCP, and the other is io_uring zerocopy added in following patches. Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/ Co-developed-by: Jakub Kicinski <kuba@kernel.org> # initial mp proposal Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:15 -08:00
net: page_pool: add callback for mp info printing Add a mandatory callback that prints information about the memory provider to netlink. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-7-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:17 -08:00
net: page_pool: add a mp hook to unregister_netdevice* Devmem TCP needs a hook in unregister_netdevice_many_notify() to upkeep the set tracking queues it's bound to, i.e. ->bound_rxqs. Instead of devmem sticking directly out of the genetic path, add a mp function. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-8-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:18 -08:00
net: devmem: fix kernel panic when netlink socket close after module unload Kernel panic occurs when a devmem TCP socket is closed after NIC module is unloaded. This is Devmem TCP unregistration scenarios. number is an order. (a)netlink socket close (b)pp destroy (c)uninstall result 1 2 3 OK 1 3 2 (d)Impossible 2 1 3 OK 3 1 2 (e)Kernel panic 2 3 1 (d)Impossible 3 2 1 (d)Impossible (a) netdev_nl_sock_priv_destroy() is called when devmem TCP socket is closed. (b) page_pool_destroy() is called when the interface is down. (c) mp_ops->uninstall() is called when an interface is unregistered. (d) There is no scenario in mp_ops->uninstall() is called before page_pool_destroy(). Because unregister_netdevice_many_notify() closes interfaces first and then calls mp_ops->uninstall(). (e) netdev_nl_sock_priv_destroy() accesses struct net_device to acquire netdev_lock(). But if the interface module has already been removed, net_device pointer is invalid, so it causes kernel panic. In summary, there are only 3 possible scenarios. A. sk close -> pp destroy -> uninstall. B. pp destroy -> sk close -> uninstall. C. pp destroy -> uninstall -> sk close. Case C is a kernel panic scenario. In order to fix this problem, It makes mp_dmabuf_devmem_uninstall() set binding->dev to NULL. It indicates an bound net_device was unregistered. It makes netdev_nl_sock_priv_destroy() do not acquire netdev_lock() if binding->dev is NULL. A new binding->lock is added to protect a dev of a binding. So, lock ordering is like below. priv->lock netdev_lock(dev) binding->lock Tests: Scenario A: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 kill $pid ip link set $interface down modprobe -rv $module Scenario B: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 ip link set $interface down kill $pid modprobe -rv $module Scenario C: ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \ -v 7 -t 1 -q 1 & pid=$! sleep 10 modprobe -rv $module sleep 5 kill $pid Splat looks like: Oops: general protection fault, probably for non-canonical address 0xdffffc001fffa9f7: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI KASAN: probably user-memory-access in range [0x00000000fffd4fb8-0x00000000fffd4fbf] CPU: 0 UID: 0 PID: 2041 Comm: ncdevmem Tainted: G B W 6.15.0-rc1+ #2 PREEMPT(undef) 0947ec89efa0fd68838b78e36aa1617e97ff5d7f Tainted: [B]=BAD_PAGE, [W]=WARN RIP: 0010:__mutex_lock (./include/linux/sched.h:2244 kernel/locking/mutex.c:400 kernel/locking/mutex.c:443 kernel/locking/mutex.c:605 kernel/locking/mutex.c:746) Code: ea 03 80 3c 02 00 0f 85 4f 13 00 00 49 8b 1e 48 83 e3 f8 74 6a 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 34 48 89 fa 48 c1 ea 03 <0f> b6 f RSP: 0018:ffff88826f7ef730 EFLAGS: 00010203 RAX: dffffc0000000000 RBX: 00000000fffd4f88 RCX: ffffffffaa9bc811 RDX: 000000001fffa9f7 RSI: 0000000000000008 RDI: 00000000fffd4fbc RBP: ffff88826f7ef8b0 R08: 0000000000000000 R09: ffffed103e6aa1a4 R10: 0000000000000007 R11: ffff88826f7ef442 R12: fffffbfff669f65e R13: ffff88812a830040 R14: ffff8881f3550d20 R15: 00000000fffd4f88 FS: 0000000000000000(0000) GS:ffff888866c05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563bed0cb288 CR3: 00000001a7c98000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <TASK> ... netdev_nl_sock_priv_destroy (net/core/netdev-genl.c:953 (discriminator 3)) genl_release (net/netlink/genetlink.c:653 net/netlink/genetlink.c:694 net/netlink/genetlink.c:705) ... netlink_release (net/netlink/af_netlink.c:737) ... __sock_release (net/socket.c:647) sock_close (net/socket.c:1393) Fixes: 1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250514154028.1062909-1-ap420073@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-14 15:40:28 +00:00
net: page_pool: add a mp hook to unregister_netdevice* Devmem TCP needs a hook in unregister_netdevice_many_notify() to upkeep the set tracking queues it's bound to, i.e. ->bound_rxqs. Instead of devmem sticking directly out of the genetic path, add a mp function. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-8-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:18 -08:00
net: page_pool: create hooks for custom memory providers A spin off from the original page pool memory providers patch by Jakub, which allows extending page pools with custom allocators. One of such providers is devmem TCP, and the other is io_uring zerocopy added in following patches. Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/ Co-developed-by: Jakub Kicinski <kuba@kernel.org> # initial mp proposal Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:15 -08:00
net: page_pool: add callback for mp info printing Add a mandatory callback that prints information about the memory provider to netlink. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-7-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:17 -08:00
net: page_pool: add a mp hook to unregister_netdevice* Devmem TCP needs a hook in unregister_netdevice_many_notify() to upkeep the set tracking queues it's bound to, i.e. ->bound_rxqs. Instead of devmem sticking directly out of the genetic path, add a mp function. Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-8-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:18 -08:00
net: page_pool: create hooks for custom memory providers A spin off from the original page pool memory providers patch by Jakub, which allows extending page pools with custom allocators. One of such providers is devmem TCP, and the other is io_uring zerocopy added in following patches. Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/ Co-developed-by: Jakub Kicinski <kuba@kernel.org> # initial mp proposal Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-04 13:56:15 -08:00