Implement a memory provider that allocates dmabuf devmem page_pool_iovs. Support of PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, and PP_FLAG_PAGE_FRAG is omitted. PP_FLAG_DMA_MAP is irrelevant as dma-buf devmem is already mapped. The other flags are omitted for simplicity. 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 page_pool_params. 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. Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: Kaiyuan Zhang <kaiyuanz@xxxxxxxxxx> Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> --- include/net/page_pool.h | 58 ++++++++++++++++++++++++++++++ net/core/page_pool.c | 79 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 137 insertions(+) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index e395f82e182b..537eb36115ed 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -32,6 +32,7 @@ #include <linux/mm.h> /* Needed by ptr_ring */ #include <linux/ptr_ring.h> #include <linux/dma-direction.h> +#include <net/net_debug.h> #define PP_FLAG_DMA_MAP BIT(0) /* Should page_pool do the DMA * map/unmap @@ -157,6 +158,7 @@ enum pp_memory_provider_type { PP_MP_HUGE_SPLIT, /* 2MB, online page alloc */ PP_MP_HUGE, /* 2MB, all memory pre-allocated */ PP_MP_HUGE_1G, /* 1G pages, MEP, pre-allocated */ + PP_MP_DMABUF_DEVMEM, /* dmabuf devmem provider */ }; struct pp_memory_provider_ops { @@ -170,9 +172,15 @@ extern const struct pp_memory_provider_ops basic_ops; extern const struct pp_memory_provider_ops hugesp_ops; extern const struct pp_memory_provider_ops huge_ops; extern const struct pp_memory_provider_ops huge_1g_ops; +extern const struct pp_memory_provider_ops dmabuf_devmem_ops; /* page_pool_iov support */ +/* We overload the LSB of the struct page pointer to indicate whether it's + * a page or page_pool_iov. + */ +#define PP_DEVMEM 0x01UL + /* Owner of the dma-buf chunks inserted into the gen pool. Each scatterlist * entry from the dmabuf is inserted into the genpool as a chunk, and needs * this owner struct to keep track of some metadata necessary to create @@ -196,6 +204,8 @@ struct page_pool_iov { struct dmabuf_genpool_chunk_owner *owner; refcount_t refcount; + + struct page_pool *pp; }; static inline struct dmabuf_genpool_chunk_owner * @@ -218,12 +228,60 @@ page_pool_iov_dma_addr(const struct page_pool_iov *ppiov) ((dma_addr_t)page_pool_iov_idx(ppiov) << PAGE_SHIFT); } +static inline unsigned long +page_pool_iov_virtual_addr(const struct page_pool_iov *ppiov) +{ + struct dmabuf_genpool_chunk_owner *owner = page_pool_iov_owner(ppiov); + + return owner->base_virtual + + ((unsigned long)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; } +static inline int page_pool_iov_refcount(const struct page_pool_iov *ppiov) +{ + return refcount_read(&ppiov->refcount); +} + +static inline void page_pool_iov_get_many(struct page_pool_iov *ppiov, + unsigned int count) +{ + refcount_add(count, &ppiov->refcount); +} + +void __page_pool_iov_free(struct page_pool_iov *ppiov); + +static inline void page_pool_iov_put_many(struct page_pool_iov *ppiov, + unsigned int count) +{ + if (!refcount_sub_and_test(count, &ppiov->refcount)) + return; + + __page_pool_iov_free(ppiov); +} + +/* page pool mm helpers */ + +static inline bool page_is_page_pool_iov(const struct page *page) +{ + return (unsigned long)page & PP_DEVMEM; +} + +static inline struct page_pool_iov *page_to_page_pool_iov(struct page *page) +{ + if (page_is_page_pool_iov(page)) + return (struct page_pool_iov *)((unsigned long)page & + ~PP_DEVMEM); + + DEBUG_NET_WARN_ON_ONCE(true); + return NULL; +} + struct page_pool { struct page_pool_params p; diff --git a/net/core/page_pool.c b/net/core/page_pool.c index df3f431fcff3..0a7c08d748b8 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -20,6 +20,7 @@ #include <linux/poison.h> #include <linux/ethtool.h> #include <linux/netdevice.h> +#include <linux/genalloc.h> #include <trace/events/page_pool.h> @@ -236,6 +237,9 @@ static int page_pool_init(struct page_pool *pool, case PP_MP_HUGE_1G: pool->mp_ops = &huge_1g_ops; break; + case PP_MP_DMABUF_DEVMEM: + pool->mp_ops = &dmabuf_devmem_ops; + break; default: err = -EINVAL; goto free_ptr_ring; @@ -1006,6 +1010,15 @@ bool page_pool_return_skb_page(struct page *page, bool napi_safe) } EXPORT_SYMBOL(page_pool_return_skb_page); +void __page_pool_iov_free(struct page_pool_iov *ppiov) +{ + if (ppiov->pp->mp_ops != &dmabuf_devmem_ops) + return; + + netdev_free_devmem(ppiov); +} +EXPORT_SYMBOL_GPL(__page_pool_iov_free); + /*********************** * Mem provider hack * ***********************/ @@ -1538,3 +1551,69 @@ const struct pp_memory_provider_ops huge_1g_ops = { .alloc_pages = mp_huge_1g_alloc_pages, .release_page = mp_huge_1g_release, }; + +/*** "Dmabuf devmem memory provider" ***/ + +static int mp_dmabuf_devmem_init(struct page_pool *pool) +{ + struct netdev_dmabuf_binding *binding = pool->mp_priv; + + if (!binding) + return -EINVAL; + + if (pool->p.flags & PP_FLAG_DMA_MAP || + pool->p.flags & PP_FLAG_DMA_SYNC_DEV || + pool->p.flags & PP_FLAG_PAGE_FRAG) + return -EOPNOTSUPP; + + netdev_devmem_binding_get(binding); + return 0; +} + +static struct page *mp_dmabuf_devmem_alloc_pages(struct page_pool *pool, + gfp_t gfp) +{ + struct netdev_dmabuf_binding *binding = pool->mp_priv; + struct page_pool_iov *ppiov; + + ppiov = netdev_alloc_devmem(binding); + if (!ppiov) + return NULL; + + ppiov->pp = pool; + pool->pages_state_hold_cnt++; + trace_page_pool_state_hold(pool, (struct page *)ppiov, + pool->pages_state_hold_cnt); + ppiov = (struct page_pool_iov *)((unsigned long)ppiov | PP_DEVMEM); + + return (struct page *)ppiov; +} + +static void mp_dmabuf_devmem_destroy(struct page_pool *pool) +{ + struct netdev_dmabuf_binding *binding = pool->mp_priv; + + netdev_devmem_binding_put(binding); +} + +static bool mp_dmabuf_devmem_release_page(struct page_pool *pool, + struct page *page) +{ + struct page_pool_iov *ppiov; + + if (WARN_ON_ONCE(!page_is_page_pool_iov(page))) + return false; + + ppiov = page_to_page_pool_iov(page); + page_pool_iov_put_many(ppiov, 1); + /* We don't want the page pool put_page()ing our page_pool_iovs. */ + return false; +} + +const struct pp_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); -- 2.41.0.640.ga95def55d0-goog