Implement a memory provider that allocates dmabuf devmem page_pool_iovs.
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.
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.
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: - static_branch check in page_is_page_pool_iov() (Willem & Paolo). - PP_DEVMEM -> PP_IOV (David). - Require PP_FLAG_DMA_MAP (Jakub).
--- include/net/page_pool/helpers.h | 47 +++++++++++++++++ include/net/page_pool/types.h | 9 ++++ net/core/page_pool.c | 89 ++++++++++++++++++++++++++++++++- 3 files changed, 144 insertions(+), 1 deletion(-)
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 8bfc2d43efd4..00197f14aa87 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -53,6 +53,8 @@ #define _NET_PAGE_POOL_HELPERS_H
#include <net/page_pool/types.h> +#include <net/net_debug.h> +#include <net/devmem.h>
#ifdef CONFIG_PAGE_POOL_STATS /* Deprecated driver-facing API, use netlink instead */ @@ -92,6 +94,11 @@ static inline unsigned int page_pool_iov_idx(const struct page_pool_iov *ppiov) return ppiov - page_pool_iov_owner(ppiov)->ppiovs; }
+static inline u32 page_pool_iov_binding_id(const struct page_pool_iov *ppiov) +{ + return page_pool_iov_owner(ppiov)->binding->id; +} + static inline dma_addr_t page_pool_iov_dma_addr(const struct page_pool_iov *ppiov) { @@ -107,6 +114,46 @@ 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 */ + +DECLARE_STATIC_KEY_FALSE(page_pool_mem_providers); +static inline bool page_is_page_pool_iov(const struct page *page) +{ + return static_branch_unlikely(&page_pool_mem_providers) && + (unsigned long)page & PP_IOV; +} + +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_IOV); + + DEBUG_NET_WARN_ON_ONCE(true); + return NULL; +} + /** * page_pool_dev_alloc_pages() - allocate a page. * @pool: pool from which to allocate diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h index 44faee7a7b02..136930a238de 100644 --- a/include/net/page_pool/types.h +++ b/include/net/page_pool/types.h @@ -134,8 +134,15 @@ struct memory_provider_ops { bool (*release_page)(struct page_pool *pool, struct page *page); };
+extern const struct 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_IOV 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 @@ -159,6 +166,8 @@ struct page_pool_iov { struct dmabuf_genpool_chunk_owner *owner;
refcount_t refcount; + + struct page_pool *pp; };
struct page_pool { diff --git a/net/core/page_pool.c b/net/core/page_pool.c index f5c84d2a4510..423c88564a00 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -12,6 +12,7 @@
#include <net/page_pool/helpers.h> #include <net/xdp.h> +#include <net/netdev_rx_queue.h>
#include <linux/dma-direction.h> #include <linux/dma-mapping.h> @@ -20,12 +21,15 @@ #include <linux/poison.h> #include <linux/ethtool.h> #include <linux/netdevice.h> +#include <linux/genalloc.h> +#include <net/devmem.h>
#include <trace/events/page_pool.h>
#include "page_pool_priv.h"
-static DEFINE_STATIC_KEY_FALSE(page_pool_mem_providers); +DEFINE_STATIC_KEY_FALSE(page_pool_mem_providers); +EXPORT_SYMBOL(page_pool_mem_providers);
#define DEFER_TIME (msecs_to_jiffies(1000)) #define DEFER_WARN_INTERVAL (60 * HZ) @@ -175,6 +179,7 @@ static void page_pool_producer_unlock(struct page_pool *pool, static int page_pool_init(struct page_pool *pool, const struct page_pool_params *params) { + struct netdev_dmabuf_binding *binding = NULL; unsigned int ring_qsize = 1024; /* Default */ int err;
@@ -237,6 +242,14 @@ static int page_pool_init(struct page_pool *pool, /* Driver calling page_pool_create() also call page_pool_destroy() */ refcount_set(&pool->user_cnt, 1);
+ if (pool->p.queue) + binding = READ_ONCE(pool->p.queue->binding); + + if (binding) { + pool->mp_ops = &dmabuf_devmem_ops; + pool->mp_priv = binding; + } + if (pool->mp_ops) { err = pool->mp_ops->init(pool); if (err) { @@ -1020,3 +1033,77 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid) } } EXPORT_SYMBOL(page_pool_update_nid); + +void __page_pool_iov_free(struct page_pool_iov *ppiov) +{ + if (WARN_ON(ppiov->pp->mp_ops != &dmabuf_devmem_ops)) + return; + + netdev_free_dmabuf(ppiov); +} +EXPORT_SYMBOL_GPL(__page_pool_iov_free); + +/*** "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)) + return -EOPNOTSUPP; + + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) + return -EOPNOTSUPP; + + netdev_dmabuf_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_dmabuf(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); + return (struct page *)((unsigned long)ppiov | PP_IOV); +} + +static void mp_dmabuf_devmem_destroy(struct page_pool *pool) +{ + struct netdev_dmabuf_binding *binding = pool->mp_priv; + + netdev_dmabuf_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 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);