On 12/18/23 02:40, Mina Almasry wrote:
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@xxxxxxxxxx> Signed-off-by: Kaiyuan Zhang <kaiyuanz@xxxxxxxxxx> Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> ---
...
+ +static bool mp_dmabuf_devmem_release_page(struct page_pool *pool, + struct netmem *netmem) +{ + WARN_ON_ONCE(!netmem_is_net_iov(netmem)); + + page_pool_clear_pp_info(netmem); + + netdev_free_dmabuf(netmem_to_net_iov(netmem)); + + /* We don't want the page pool put_page()ing our net_iovs. */ + return false; +} + +const struct memory_provider_ops dmabuf_devmem_ops = { + .init = mp_dmabuf_devmem_init, + .destroy = mp_dmabuf_devmem_destroy, + .alloc_pages = mp_dmabuf_devmem_alloc_pages, + .release_page = mp_dmabuf_devmem_release_page, +}; +EXPORT_SYMBOL(dmabuf_devmem_ops);
It might make sense to move all these functions together with new code from core/dev.c into a new file -- Pavel Begunkov