Implement a few updates to Jakub's RFC memory provider[1] API to make it suitable for device memory TCP:
1. Currently for devmem TCP the driver's netdev_rx_queue holds a reference to the netdev_dmabuf_binding struct and needs to pass that to the page_pool's memory provider somehow. For PoC purposes, create a pp->mp_priv field that is set by the driver. Likely needs a better API (likely dependent on the general memory provider API). 2. The current memory_provider API gives the memory_provider the option to override put_page(), but tries page_pool_clear_pp_info() after the memory provider has released the page. IMO if the page freeing is delegated to the provider then the page_pool should not modify the page after release_page() has been called. [1]: https://lore.kernel.org/netdev/20230707183935.997267-1-k...@kernel.org/ Signed-off-by: Mina Almasry <almasrym...@google.com> --- include/net/page_pool.h | 1 + net/core/page_pool.c | 7 ++++--- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index 13ae7f668c9e..e395f82e182b 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -78,6 +78,7 @@ struct page_pool_params { struct device *dev; /* device, for DMA pre-mapping purposes */ struct napi_struct *napi; /* Sole consumer of pages, otherwise NULL */ u8 memory_provider; /* haaacks! should be user-facing */ + void *mp_priv; /* argument to pass to the memory provider */ enum dma_data_direction dma_dir; /* DMA mapping direction */ unsigned int max_len; /* max DMA sync memory size */ unsigned int offset; /* DMA addr offset */ diff --git a/net/core/page_pool.c b/net/core/page_pool.c index d50f6728e4f6..df3f431fcff3 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -241,6 +241,7 @@ static int page_pool_init(struct page_pool *pool, goto free_ptr_ring; } + pool->mp_priv = pool->p.mp_priv; if (pool->mp_ops) { err = pool->mp_ops->init(pool); if (err) { @@ -564,16 +565,16 @@ void page_pool_return_page(struct page_pool *pool, struct page *page) else __page_pool_release_page_dma(pool, page); - page_pool_clear_pp_info(page); - /* This may be the last page returned, releasing the pool, so * it is not safe to reference pool afterwards. */ count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt); trace_page_pool_state_release(pool, page, count); - if (put) + if (put) { + page_pool_clear_pp_info(page); put_page(page); + } /* An optimization would be to call __free_pages(page, pool->p.order) * knowing page is not part of page-cache (thus avoiding a * __page_cache_release() call). -- 2.41.0.640.ga95def55d0-goog
