Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates page_pool_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 page_pool_iov struct.
page_pool_iov are refcounted and are freed back to the binding when the refcount drops to 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
---
v1: - Rename devmem -> dmabuf (David).
--- include/net/devmem.h | 13 ++++++++++++ include/net/page_pool/helpers.h | 28 +++++++++++++++++++++++++ net/core/dev.c | 37 ++++++++++++++++++++++++++++++++- 3 files changed, 77 insertions(+), 1 deletion(-)
diff --git a/include/net/devmem.h b/include/net/devmem.h index 29ff125f9815..29bc337c7743 100644 --- a/include/net/devmem.h +++ b/include/net/devmem.h @@ -48,6 +48,9 @@ struct netdev_dmabuf_binding { };
#ifdef CONFIG_DMA_SHARED_BUFFER +struct page_pool_iov * +netdev_alloc_dmabuf(struct netdev_dmabuf_binding *binding); +void netdev_free_dmabuf(struct page_pool_iov *ppiov); void __netdev_dmabuf_binding_free(struct netdev_dmabuf_binding *binding); int netdev_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, struct netdev_dmabuf_binding **out); @@ -55,6 +58,16 @@ void netdev_unbind_dmabuf(struct netdev_dmabuf_binding *binding); int netdev_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, struct netdev_dmabuf_binding *binding); #else +static inline struct page_pool_iov * +netdev_alloc_dmabuf(struct netdev_dmabuf_binding *binding) +{ + return NULL; +} + +static inline void netdev_free_dmabuf(struct page_pool_iov *ppiov) +{ +} + static inline void __netdev_dmabuf_binding_free(struct netdev_dmabuf_binding *binding) { diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 7dc65774cde5..8bfc2d43efd4 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -79,6 +79,34 @@ static inline u64 *page_pool_ethtool_stats_get(u64 *data, void *stats) } #endif
+/* page_pool_iov support */ + +static inline struct dmabuf_genpool_chunk_owner * +page_pool_iov_owner(const struct page_pool_iov *ppiov) +{ + return ppiov->owner; +} + +static inline unsigned int page_pool_iov_idx(const struct page_pool_iov *ppiov) +{ + return ppiov - page_pool_iov_owner(ppiov)->ppiovs; +} + +static inline dma_addr_t +page_pool_iov_dma_addr(const struct page_pool_iov *ppiov) +{ + struct dmabuf_genpool_chunk_owner *owner = page_pool_iov_owner(ppiov); + + return owner->base_dma_addr + + ((dma_addr_t)page_pool_iov_idx(ppiov) << PAGE_SHIFT); +} + +static inline struct netdev_dmabuf_binding * +page_pool_iov_binding(const struct page_pool_iov *ppiov) +{ + return page_pool_iov_owner(ppiov)->binding; +} + /** * page_pool_dev_alloc_pages() - allocate a page. * @pool: pool from which to allocate diff --git a/net/core/dev.c b/net/core/dev.c index b8c8be5a912e..30667e4c3b95 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -155,8 +155,8 @@ #include <net/netdev_rx_queue.h> #include <linux/genalloc.h> #include <linux/dma-buf.h> -#include <net/page_pool/types.h> #include <net/devmem.h> +#include <net/page_pool/helpers.h>
#include "dev.h" #include "net-sysfs.h" @@ -2120,6 +2120,41 @@ static int netdev_restart_rx_queue(struct net_device *dev, int rxq_idx) return err; }
+struct page_pool_iov *netdev_alloc_dmabuf(struct netdev_dmabuf_binding *binding) +{ + struct dmabuf_genpool_chunk_owner *owner; + struct page_pool_iov *ppiov; + unsigned long dma_addr; + ssize_t offset; + ssize_t index; + + dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE, + (void **)&owner); + if (!dma_addr) + return NULL; + + offset = dma_addr - owner->base_dma_addr; + index = offset / PAGE_SIZE; + ppiov = &owner->ppiovs[index]; + + netdev_dmabuf_binding_get(binding); + + return ppiov; +} + +void netdev_free_dmabuf(struct page_pool_iov *ppiov) +{ + struct netdev_dmabuf_binding *binding = page_pool_iov_binding(ppiov); + unsigned long dma_addr = page_pool_iov_dma_addr(ppiov); + + refcount_set(&ppiov->refcount, 1); + + if (gen_pool_has_addr(binding->chunk_pool, dma_addr, PAGE_SIZE)) + gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE); + + netdev_dmabuf_binding_put(binding); +} + /* Protected by rtnl_lock() */ static DEFINE_XARRAY_FLAGS(netdev_dmabuf_bindings, XA_FLAGS_ALLOC1);