Resguardo inicial

linux-7.2.3/include/net/page_pool/helpers.h

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+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * page_pool/helpers.h
+ *	Author:	Jesper Dangaard Brouer <netoptimizer@brouer.com>
+ *	Copyright (C) 2016 Red Hat, Inc.
+ */
+
+/**
+ * DOC: page_pool allocator
+ *
+ * The page_pool allocator is optimized for recycling page or page fragment used
+ * by skb packet and xdp frame.
+ *
+ * Basic use involves replacing any alloc_pages() calls with page_pool_alloc(),
+ * which allocate memory with or without page splitting depending on the
+ * requested memory size.
+ *
+ * If the driver knows that it always requires full pages or its allocations are
+ * always smaller than half a page, it can use one of the more specific API
+ * calls:
+ *
+ * 1. page_pool_alloc_pages(): allocate memory without page splitting when
+ * driver knows that the memory it need is always bigger than half of the page
+ * allocated from page pool. There is no cache line dirtying for 'struct page'
+ * when a page is recycled back to the page pool.
+ *
+ * 2. page_pool_alloc_frag(): allocate memory with page splitting when driver
+ * knows that the memory it need is always smaller than or equal to half of the
+ * page allocated from page pool. Page splitting enables memory saving and thus
+ * avoids TLB/cache miss for data access, but there also is some cost to
+ * implement page splitting, mainly some cache line dirtying/bouncing for
+ * 'struct page' and atomic operation for page->pp_ref_count.
+ *
+ * The API keeps track of in-flight pages, in order to let API users know when
+ * it is safe to free a page_pool object, the API users must call
+ * page_pool_put_page() or page_pool_free_va() to free the page_pool object, or
+ * attach the page_pool object to a page_pool-aware object like skbs marked with
+ * skb_mark_for_recycle().
+ *
+ * page_pool_put_page() may be called multiple times on the same page if a page
+ * is split into multiple fragments. For the last fragment, it will either
+ * recycle the page, or in case of page->_refcount > 1, it will release the DMA
+ * mapping and in-flight state accounting.
+ *
+ * dma_sync_single_range_for_device() is only called for the last fragment when
+ * page_pool is created with PP_FLAG_DMA_SYNC_DEV flag, so it depends on the
+ * last freed fragment to do the sync_for_device operation for all fragments in
+ * the same page when a page is split. The API user must setup pool->p.max_len
+ * and pool->p.offset correctly and ensure that page_pool_put_page() is called
+ * with dma_sync_size being -1 for fragment API.
+ */
+#ifndef _NET_PAGE_POOL_HELPERS_H
+#define _NET_PAGE_POOL_HELPERS_H
+
+#include <linux/dma-mapping.h>
+
+#include <net/page_pool/types.h>
+#include <net/net_debug.h>
+#include <net/netmem.h>
+
+#ifdef CONFIG_PAGE_POOL_STATS
+/* Deprecated driver-facing API, use netlink instead */
+int page_pool_ethtool_stats_get_count(void);
+u8 *page_pool_ethtool_stats_get_strings(u8 *data);
+u64 *page_pool_ethtool_stats_get(u64 *data, const void *stats);
+
+void page_pool_get_stats(const struct page_pool *pool,
+			 struct page_pool_stats *stats);
+#else
+static inline int page_pool_ethtool_stats_get_count(void)
+{
+	return 0;
+}
+
+static inline u8 *page_pool_ethtool_stats_get_strings(u8 *data)
+{
+	return data;
+}
+
+static inline u64 *page_pool_ethtool_stats_get(u64 *data, const void *stats)
+{
+	return data;
+}
+#endif
+
+/**
+ * page_pool_dev_alloc_pages() - allocate a page.
+ * @pool:	pool from which to allocate
+ *
+ * Get a page from the page allocator or page_pool caches.
+ */
+static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
+{
+	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+	return page_pool_alloc_pages(pool, gfp);
+}
+
+/**
+ * page_pool_dev_alloc_frag() - allocate a page fragment.
+ * @pool: pool from which to allocate
+ * @offset: offset to the allocated page
+ * @size: requested size
+ *
+ * Get a page fragment from the page allocator or page_pool caches.
+ *
+ * Return: allocated page fragment, otherwise return NULL.
+ */
+static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
+						    unsigned int *offset,
+						    unsigned int size)
+{
+	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+	return page_pool_alloc_frag(pool, offset, size, gfp);
+}
+
+static inline netmem_ref page_pool_alloc_netmem(struct page_pool *pool,
+						unsigned int *offset,
+						unsigned int *size, gfp_t gfp)
+{
+	unsigned int max_size = PAGE_SIZE << pool->p.order;
+	netmem_ref netmem;
+
+	if ((*size << 1) > max_size) {
+		*size = max_size;
+		*offset = 0;
+		return page_pool_alloc_netmems(pool, gfp);
+	}
+
+	netmem = page_pool_alloc_frag_netmem(pool, offset, *size, gfp);
+	if (unlikely(!netmem))
+		return 0;
+
+	/* There is very likely not enough space for another fragment, so append
+	 * the remaining size to the current fragment to avoid truesize
+	 * underestimate problem.
+	 */
+	if (pool->frag_offset + *size > max_size) {
+		*size = max_size - *offset;
+		pool->frag_offset = max_size;
+	}
+
+	return netmem;
+}
+
+static inline netmem_ref page_pool_dev_alloc_netmem(struct page_pool *pool,
+						    unsigned int *offset,
+						    unsigned int *size)
+{
+	gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;
+
+	return page_pool_alloc_netmem(pool, offset, size, gfp);
+}
+
+static inline netmem_ref page_pool_dev_alloc_netmems(struct page_pool *pool)
+{
+	gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;
+
+	return page_pool_alloc_netmems(pool, gfp);
+}
+
+static inline struct page *page_pool_alloc(struct page_pool *pool,
+					   unsigned int *offset,
+					   unsigned int *size, gfp_t gfp)
+{
+	return netmem_to_page(page_pool_alloc_netmem(pool, offset, size, gfp));
+}
+
+/**
+ * page_pool_dev_alloc() - allocate a page or a page fragment.
+ * @pool: pool from which to allocate
+ * @offset: offset to the allocated page
+ * @size: in as the requested size, out as the allocated size
+ *
+ * Get a page or a page fragment from the page allocator or page_pool caches
+ * depending on the requested size in order to allocate memory with least memory
+ * utilization and performance penalty.
+ *
+ * Return: allocated page or page fragment, otherwise return NULL.
+ */
+static inline struct page *page_pool_dev_alloc(struct page_pool *pool,
+					       unsigned int *offset,
+					       unsigned int *size)
+{
+	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+	return page_pool_alloc(pool, offset, size, gfp);
+}
+
+static inline void *page_pool_alloc_va(struct page_pool *pool,
+				       unsigned int *size, gfp_t gfp)
+{
+	unsigned int offset;
+	struct page *page;
+
+	/* Mask off __GFP_HIGHMEM to ensure we can use page_address() */
+	page = page_pool_alloc(pool, &offset, size, gfp & ~__GFP_HIGHMEM);
+	if (unlikely(!page))
+		return NULL;
+
+	return page_address(page) + offset;
+}
+
+/**
+ * page_pool_dev_alloc_va() - allocate a page or a page fragment and return its
+ *			      va.
+ * @pool: pool from which to allocate
+ * @size: in as the requested size, out as the allocated size
+ *
+ * This is just a thin wrapper around the page_pool_alloc() API, and
+ * it returns va of the allocated page or page fragment.
+ *
+ * Return: the va for the allocated page or page fragment, otherwise return NULL.
+ */
+static inline void *page_pool_dev_alloc_va(struct page_pool *pool,
+					   unsigned int *size)
+{
+	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+	return page_pool_alloc_va(pool, size, gfp);
+}
+
+/**
+ * page_pool_get_dma_dir() - Retrieve the stored DMA direction.
+ * @pool:	pool from which page was allocated
+ *
+ * Get the stored dma direction. A driver might decide to store this locally
+ * and avoid the extra cache line from page_pool to determine the direction.
+ */
+static inline enum dma_data_direction
+page_pool_get_dma_dir(const struct page_pool *pool)
+{
+	return pool->p.dma_dir;
+}
+
+static inline void page_pool_fragment_netmem(netmem_ref netmem, long nr)
+{
+	atomic_long_set(netmem_get_pp_ref_count_ref(netmem), nr);
+}
+
+/**
+ * page_pool_fragment_page() - split a fresh page into fragments
+ * @page:	page to split
+ * @nr:		references to set
+ *
+ * pp_ref_count represents the number of outstanding references to the page,
+ * which will be freed using page_pool APIs (rather than page allocator APIs
+ * like put_page()). Such references are usually held by page_pool-aware
+ * objects like skbs marked for page pool recycling.
+ *
+ * This helper allows the caller to take (set) multiple references to a
+ * freshly allocated page. The page must be freshly allocated (have a
+ * pp_ref_count of 1). This is commonly done by drivers and
+ * "fragment allocators" to save atomic operations - either when they know
+ * upfront how many references they will need; or to take MAX references and
+ * return the unused ones with a single atomic dec(), instead of performing
+ * multiple atomic inc() operations.
+ */
+static inline void page_pool_fragment_page(struct page *page, long nr)
+{
+	page_pool_fragment_netmem(page_to_netmem(page), nr);
+}
+
+static inline long page_pool_unref_netmem(netmem_ref netmem, long nr)
+{
+	atomic_long_t *pp_ref_count = netmem_get_pp_ref_count_ref(netmem);
+	long ret;
+
+	/* If nr == pp_ref_count then we have cleared all remaining
+	 * references to the page:
+	 * 1. 'n == 1': no need to actually overwrite it.
+	 * 2. 'n != 1': overwrite it with one, which is the rare case
+	 *              for pp_ref_count draining.
+	 *
+	 * The main advantage to doing this is that not only we avoid a atomic
+	 * update, as an atomic_read is generally a much cheaper operation than
+	 * an atomic update, especially when dealing with a page that may be
+	 * referenced by only 2 or 3 users; but also unify the pp_ref_count
+	 * handling by ensuring all pages have partitioned into only 1 piece
+	 * initially, and only overwrite it when the page is partitioned into
+	 * more than one piece.
+	 */
+	if (atomic_long_read(pp_ref_count) == nr) {
+		/* As we have ensured nr is always one for constant case using
+		 * the BUILD_BUG_ON(), only need to handle the non-constant case
+		 * here for pp_ref_count draining, which is a rare case.
+		 */
+		BUILD_BUG_ON(__builtin_constant_p(nr) && nr != 1);
+		if (!__builtin_constant_p(nr))
+			atomic_long_set(pp_ref_count, 1);
+
+		return 0;
+	}
+
+	ret = atomic_long_sub_return(nr, pp_ref_count);
+	WARN_ON(ret < 0);
+
+	/* We are the last user here too, reset pp_ref_count back to 1 to
+	 * ensure all pages have been partitioned into 1 piece initially,
+	 * this should be the rare case when the last two fragment users call
+	 * page_pool_unref_page() currently.
+	 */
+	if (unlikely(!ret))
+		atomic_long_set(pp_ref_count, 1);
+
+	return ret;
+}
+
+static inline long page_pool_unref_page(struct page *page, long nr)
+{
+	return page_pool_unref_netmem(page_to_netmem(page), nr);
+}
+
+static inline void page_pool_ref_netmem(netmem_ref netmem)
+{
+	atomic_long_inc(netmem_get_pp_ref_count_ref(netmem));
+}
+
+static inline void page_pool_ref_page(struct page *page)
+{
+	page_pool_ref_netmem(page_to_netmem(page));
+}
+
+static inline bool page_pool_unref_and_test(netmem_ref netmem)
+{
+	/* If page_pool_unref_page() returns 0, we were the last user */
+	return page_pool_unref_netmem(netmem, 1) == 0;
+}
+
+static inline void page_pool_put_netmem(struct page_pool *pool,
+					netmem_ref netmem,
+					unsigned int dma_sync_size,
+					bool allow_direct)
+{
+	/* When page_pool isn't compiled-in, net/core/xdp.c doesn't
+	 * allow registering MEM_TYPE_PAGE_POOL, but shield linker.
+	 */
+#ifdef CONFIG_PAGE_POOL
+	if (!page_pool_unref_and_test(netmem))
+		return;
+
+	page_pool_put_unrefed_netmem(pool, netmem, dma_sync_size, allow_direct);
+#endif
+}
+
+/**
+ * page_pool_put_page() - release a reference to a page pool page
+ * @pool:	pool from which page was allocated
+ * @page:	page to release a reference on
+ * @dma_sync_size: how much of the page may have been touched by the device
+ * @allow_direct: released by the consumer, allow lockless caching
+ *
+ * The outcome of this depends on the page refcnt. If the driver bumps
+ * the refcnt > 1 this will unmap the page. If the page refcnt is 1
+ * the allocator owns the page and will try to recycle it in one of the pool
+ * caches. If PP_FLAG_DMA_SYNC_DEV is set, the page will be synced for_device
+ * using dma_sync_single_range_for_device().
+ */
+static inline void page_pool_put_page(struct page_pool *pool,
+				      struct page *page,
+				      unsigned int dma_sync_size,
+				      bool allow_direct)
+{
+	page_pool_put_netmem(pool, page_to_netmem(page), dma_sync_size,
+			     allow_direct);
+}
+
+static inline void page_pool_put_full_netmem(struct page_pool *pool,
+					     netmem_ref netmem,
+					     bool allow_direct)
+{
+	page_pool_put_netmem(pool, netmem, -1, allow_direct);
+}
+
+/**
+ * page_pool_put_full_page() - release a reference on a page pool page
+ * @pool:	pool from which page was allocated
+ * @page:	page to release a reference on
+ * @allow_direct: released by the consumer, allow lockless caching
+ *
+ * Similar to page_pool_put_page(), but will DMA sync the entire memory area
+ * as configured in &page_pool_params.max_len.
+ */
+static inline void page_pool_put_full_page(struct page_pool *pool,
+					   struct page *page, bool allow_direct)
+{
+	page_pool_put_netmem(pool, page_to_netmem(page), -1, allow_direct);
+}
+
+/**
+ * page_pool_recycle_direct() - release a reference on a page pool page
+ * @pool:	pool from which page was allocated
+ * @page:	page to release a reference on
+ *
+ * Similar to page_pool_put_full_page() but caller must guarantee safe context
+ * (e.g NAPI), since it will recycle the page directly into the pool fast cache.
+ */
+static inline void page_pool_recycle_direct(struct page_pool *pool,
+					    struct page *page)
+{
+	page_pool_put_full_page(pool, page, true);
+}
+
+static inline void page_pool_recycle_direct_netmem(struct page_pool *pool,
+						   netmem_ref netmem)
+{
+	page_pool_put_full_netmem(pool, netmem, true);
+}
+
+#define PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA	\
+		(sizeof(dma_addr_t) > sizeof(unsigned long))
+
+/**
+ * page_pool_free_va() - free a va into the page_pool
+ * @pool: pool from which va was allocated
+ * @va: va to be freed
+ * @allow_direct: freed by the consumer, allow lockless caching
+ *
+ * Free a va allocated from page_pool_allo_va().
+ */
+static inline void page_pool_free_va(struct page_pool *pool, void *va,
+				     bool allow_direct)
+{
+	page_pool_put_page(pool, virt_to_head_page(va), -1, allow_direct);
+}
+
+static inline dma_addr_t page_pool_get_dma_addr_netmem(netmem_ref netmem)
+{
+	dma_addr_t ret = netmem_get_dma_addr(netmem);
+
+	if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA)
+		ret <<= PAGE_SHIFT;
+
+	return ret;
+}
+
+/**
+ * page_pool_get_dma_addr() - Retrieve the stored DMA address.
+ * @page:	page allocated from a page pool
+ *
+ * Fetch the DMA address of the page. The page pool to which the page belongs
+ * must had been created with PP_FLAG_DMA_MAP.
+ */
+static inline dma_addr_t page_pool_get_dma_addr(const struct page *page)
+{
+	return page_pool_get_dma_addr_netmem(page_to_netmem(page));
+}
+
+static inline void __page_pool_dma_sync_for_cpu(const struct page_pool *pool,
+						const dma_addr_t dma_addr,
+						u32 offset, u32 dma_sync_size)
+{
+	dma_sync_single_range_for_cpu(pool->p.dev, dma_addr,
+				      offset + pool->p.offset, dma_sync_size,
+				      page_pool_get_dma_dir(pool));
+}
+
+/**
+ * page_pool_dma_sync_for_cpu - sync Rx page for CPU after it's written by HW
+ * @pool: &page_pool the @page belongs to
+ * @page: page to sync
+ * @offset: offset from page start to "hard" start if using PP frags
+ * @dma_sync_size: size of the data written to the page
+ *
+ * Can be used as a shorthand to sync Rx pages before accessing them in the
+ * driver. Caller must ensure the pool was created with ``PP_FLAG_DMA_MAP``.
+ * Note that this version performs DMA sync unconditionally, even if the
+ * associated PP doesn't perform sync-for-device.
+ */
+static inline void page_pool_dma_sync_for_cpu(const struct page_pool *pool,
+					      const struct page *page,
+					      u32 offset, u32 dma_sync_size)
+{
+	__page_pool_dma_sync_for_cpu(pool, page_pool_get_dma_addr(page), offset,
+				     dma_sync_size);
+}
+
+static inline void
+page_pool_dma_sync_netmem_for_cpu(const struct page_pool *pool,
+				  const netmem_ref netmem, u32 offset,
+				  u32 dma_sync_size)
+{
+	if (!pool->dma_sync_for_cpu)
+		return;
+
+	__page_pool_dma_sync_for_cpu(pool,
+				     page_pool_get_dma_addr_netmem(netmem),
+				     offset, dma_sync_size);
+}
+
+static inline void page_pool_get(struct page_pool *pool)
+{
+	refcount_inc(&pool->user_cnt);
+}
+
+static inline bool page_pool_put(struct page_pool *pool)
+{
+	return refcount_dec_and_test(&pool->user_cnt);
+}
+
+static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
+{
+	if (unlikely(pool->p.nid != new_nid))
+		page_pool_update_nid(pool, new_nid);
+}
+
+/**
+ * page_pool_is_unreadable() - will allocated buffers be unreadable for the CPU
+ * @pool: queried page pool
+ *
+ * Check if page pool will return buffers which are unreadable to the CPU /
+ * kernel. This will only be the case if user space bound a memory provider (mp)
+ * which returns unreadable memory to the queue served by the page pool.
+ * If %PP_FLAG_ALLOW_UNREADABLE_NETMEM was set but there is no mp bound
+ * this helper will return false. See also netif_rxq_has_unreadable_mp().
+ *
+ * Return: true if memory allocated by the page pool may be unreadable
+ */
+static inline bool page_pool_is_unreadable(struct page_pool *pool)
+{
+	return !!pool->mp_ops;
+}
+
+#endif /* _NET_PAGE_POOL_HELPERS_H */

linux-7.2.3/include/net/page_pool/memory_provider.h

@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_PAGE_POOL_MEMORY_PROVIDER_H
+#define _NET_PAGE_POOL_MEMORY_PROVIDER_H
+
+#include <net/netmem.h>
+#include <net/page_pool/types.h>
+
+struct netdev_rx_queue;
+struct netlink_ext_ack;
+struct sk_buff;
+
+struct memory_provider_ops {
+	netmem_ref (*alloc_netmems)(struct page_pool *pool, gfp_t gfp);
+	bool (*release_netmem)(struct page_pool *pool, netmem_ref netmem);
+	int (*init)(struct page_pool *pool);
+	void (*destroy)(struct page_pool *pool);
+	int (*nl_fill)(void *mp_priv, struct sk_buff *rsp,
+		       struct netdev_rx_queue *rxq);
+	void (*uninstall)(void *mp_priv, struct netdev_rx_queue *rxq);
+};
+
+bool net_mp_niov_set_dma_addr(struct net_iov *niov, dma_addr_t addr);
+void net_mp_niov_set_page_pool(struct page_pool *pool, struct net_iov *niov);
+void net_mp_niov_clear_page_pool(struct net_iov *niov);
+
+int netif_mp_open_rxq(struct net_device *dev, unsigned int rxq_idx,
+		      const struct pp_memory_provider_params *p,
+		      struct netlink_ext_ack *extack);
+void netif_mp_close_rxq(struct net_device *dev, unsigned int rxq_idx,
+			const struct pp_memory_provider_params *old_p);
+
+/**
+  * net_mp_netmem_place_in_cache() - give a netmem to a page pool
+  * @pool:      the page pool to place the netmem into
+  * @netmem:    netmem to give
+  *
+  * Push an accounted netmem into the page pool's allocation cache. The caller
+  * must ensure that there is space in the cache. It should only be called off
+  * the mp_ops->alloc_netmems() path.
+  */
+static inline void net_mp_netmem_place_in_cache(struct page_pool *pool,
+						netmem_ref netmem)
+{
+	pool->alloc.cache[pool->alloc.count++] = netmem;
+}
+
+#endif

linux-7.2.3/include/net/page_pool/types.h

@@ -0,0 +1,320 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _NET_PAGE_POOL_TYPES_H
+#define _NET_PAGE_POOL_TYPES_H
+
+#include <linux/dma-direction.h>
+#include <linux/ptr_ring.h>
+#include <linux/types.h>
+#include <linux/xarray.h>
+#include <net/netmem.h>
+
+#define PP_FLAG_DMA_MAP		BIT(0) /* Should page_pool do the DMA
+					* map/unmap
+					*/
+#define PP_FLAG_DMA_SYNC_DEV	BIT(1) /* If set all pages that the driver gets
+					* from page_pool will be
+					* DMA-synced-for-device according to
+					* the length provided by the device
+					* driver.
+					* Please note DMA-sync-for-CPU is still
+					* device driver responsibility
+					*/
+#define PP_FLAG_SYSTEM_POOL	BIT(2) /* Global system page_pool */
+
+/* Allow unreadable (net_iov backed) netmem in this page_pool. Drivers setting
+ * this must be able to support unreadable netmem, where netmem_address() would
+ * return NULL. This flag should not be set for header page_pools.
+ *
+ * If the driver sets PP_FLAG_ALLOW_UNREADABLE_NETMEM, it should also set
+ * page_pool_params.slow.queue_idx.
+ */
+#define PP_FLAG_ALLOW_UNREADABLE_NETMEM BIT(3)
+
+#define PP_FLAG_ALL		(PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV | \
+				 PP_FLAG_SYSTEM_POOL | PP_FLAG_ALLOW_UNREADABLE_NETMEM)
+
+/* Index limit to stay within PP_DMA_INDEX_BITS for DMA indices */
+#define PP_DMA_INDEX_LIMIT XA_LIMIT(1, BIT(PP_DMA_INDEX_BITS) - 1)
+
+/*
+ * Fast allocation side cache array/stack
+ *
+ * The cache size and refill watermark is related to the network
+ * use-case.  The NAPI budget is 64 packets.  After a NAPI poll the RX
+ * ring is usually refilled and the max consumed elements will be 64,
+ * thus a natural max size of objects needed in the cache.
+ * The refill watermark is set to 64 for 4KB pages,
+ * and scales to balance its size in bytes across page sizes.
+ *
+ * Keeping room for more objects, is due to XDP_DROP use-case.  As
+ * XDP_DROP allows the opportunity to recycle objects directly into
+ * this array, as it shares the same softirq/NAPI protection.  If
+ * cache is already full (or partly full) then the XDP_DROP recycles
+ * would have to take a slower code path.
+ */
+#if PAGE_SIZE >= SZ_64K
+#define PP_ALLOC_CACHE_REFILL	4
+#elif PAGE_SIZE >= SZ_16K
+#define PP_ALLOC_CACHE_REFILL	16
+#else
+#define PP_ALLOC_CACHE_REFILL	64
+#endif
+
+#define PP_ALLOC_CACHE_SIZE	(PP_ALLOC_CACHE_REFILL * 2)
+struct pp_alloc_cache {
+	u32 count;
+	netmem_ref cache[PP_ALLOC_CACHE_SIZE];
+};
+
+/**
+ * struct page_pool_params - page pool parameters
+ * @fast:	params accessed frequently on hotpath
+ * @order:	2^order pages on allocation
+ * @pool_size:	size of the ptr_ring
+ * @nid:	NUMA node id to allocate from pages from
+ * @dev:	device, for DMA pre-mapping purposes
+ * @napi:	NAPI which is the sole consumer of pages, otherwise NULL
+ * @dma_dir:	DMA mapping direction
+ * @max_len:	max DMA sync memory size for PP_FLAG_DMA_SYNC_DEV
+ * @offset:	DMA sync address offset for PP_FLAG_DMA_SYNC_DEV
+ * @slow:	params with slowpath access only (initialization and Netlink)
+ * @netdev:	netdev this pool will serve (leave as NULL if none or multiple)
+ * @queue_idx:	queue idx this page_pool is being created for.
+ * @flags:	PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_SYSTEM_POOL,
+ *		PP_FLAG_ALLOW_UNREADABLE_NETMEM.
+ */
+struct page_pool_params {
+	struct_group_tagged(page_pool_params_fast, fast,
+		unsigned int	order;
+		unsigned int	pool_size;
+		int		nid;
+		struct device	*dev;
+		struct napi_struct *napi;
+		enum dma_data_direction dma_dir;
+		unsigned int	max_len;
+		unsigned int	offset;
+	);
+	struct_group_tagged(page_pool_params_slow, slow,
+		struct net_device *netdev;
+		unsigned int queue_idx;
+		unsigned int	flags;
+/* private: used by test code only */
+		void (*init_callback)(netmem_ref netmem, void *arg);
+		void *init_arg;
+	);
+};
+
+#ifdef CONFIG_PAGE_POOL_STATS
+/**
+ * struct page_pool_alloc_stats - allocation statistics
+ * @fast:	successful fast path allocations
+ * @slow:	slow path order-0 allocations
+ * @slow_high_order: slow path high order allocations
+ * @empty:	ptr ring is empty, so a slow path allocation was forced
+ * @refill:	an allocation which triggered a refill of the cache
+ * @waive:	pages obtained from the ptr ring that cannot be added to
+ *		the cache due to a NUMA mismatch
+ */
+struct page_pool_alloc_stats {
+	u64 fast;
+	u64 slow;
+	u64 slow_high_order;
+	u64 empty;
+	u64 refill;
+	u64 waive;
+};
+
+/**
+ * struct page_pool_recycle_stats - recycling (freeing) statistics
+ * @cached:	recycling placed page in the page pool cache
+ * @cache_full:	page pool cache was full
+ * @ring:	page placed into the ptr ring
+ * @ring_full:	page released from page pool because the ptr ring was full
+ * @released_refcnt:	page released (and not recycled) because refcnt > 1
+ */
+struct page_pool_recycle_stats {
+	u64 cached;
+	u64 cache_full;
+	u64 ring;
+	u64 ring_full;
+	u64 released_refcnt;
+};
+
+/**
+ * struct page_pool_stats - combined page pool use statistics
+ * @alloc_stats:	see struct page_pool_alloc_stats
+ * @recycle_stats:	see struct page_pool_recycle_stats
+ *
+ * Wrapper struct for combining page pool stats with different storage
+ * requirements.
+ */
+struct page_pool_stats {
+	struct page_pool_alloc_stats alloc_stats;
+	struct page_pool_recycle_stats recycle_stats;
+};
+#endif
+
+/* The whole frag API block must stay within one cacheline. On 32-bit systems,
+ * sizeof(long) == sizeof(int), so that the block size is ``3 * sizeof(long)``.
+ * On 64-bit systems, the actual size is ``2 * sizeof(long) + sizeof(int)``.
+ * The closest pow-2 to both of them is ``4 * sizeof(long)``, so just use that
+ * one for simplicity.
+ * Having it aligned to a cacheline boundary may be excessive and doesn't bring
+ * any good.
+ */
+#define PAGE_POOL_FRAG_GROUP_ALIGN	(4 * sizeof(long))
+
+struct memory_provider_ops;
+
+struct pp_memory_provider_params {
+	void *mp_priv;
+	const struct memory_provider_ops *mp_ops;
+	u32 rx_page_size;
+};
+
+struct page_pool {
+	struct page_pool_params_fast p;
+
+	int cpuid;
+	u32 pages_state_hold_cnt;
+
+	bool has_init_callback:1;	/* slow::init_callback is set */
+	bool dma_map:1;			/* Perform DMA mapping */
+	bool dma_sync:1;		/* Perform DMA sync for device */
+	bool dma_sync_for_cpu:1;	/* Perform DMA sync for cpu */
+#ifdef CONFIG_PAGE_POOL_STATS
+	bool system:1;			/* This is a global percpu pool */
+#endif
+
+	__cacheline_group_begin_aligned(frag, PAGE_POOL_FRAG_GROUP_ALIGN);
+	long frag_users;
+	netmem_ref frag_page;
+	unsigned int frag_offset;
+	__cacheline_group_end_aligned(frag, PAGE_POOL_FRAG_GROUP_ALIGN);
+
+	struct delayed_work release_dw;
+	void (*disconnect)(void *pool);
+	unsigned long defer_start;
+	unsigned long defer_warn;
+
+#ifdef CONFIG_PAGE_POOL_STATS
+	/* these stats are incremented while in softirq context */
+	struct page_pool_alloc_stats alloc_stats;
+#endif
+	u32 xdp_mem_id;
+
+	/*
+	 * Data structure for allocation side
+	 *
+	 * Drivers allocation side usually already perform some kind
+	 * of resource protection.  Piggyback on this protection, and
+	 * require driver to protect allocation side.
+	 *
+	 * For NIC drivers this means, allocate a page_pool per
+	 * RX-queue. As the RX-queue is already protected by
+	 * Softirq/BH scheduling and napi_schedule. NAPI schedule
+	 * guarantee that a single napi_struct will only be scheduled
+	 * on a single CPU (see napi_schedule).
+	 */
+	struct pp_alloc_cache alloc ____cacheline_aligned_in_smp;
+
+	/* Data structure for storing recycled pages.
+	 *
+	 * Returning/freeing pages is more complicated synchronization
+	 * wise, because free's can happen on remote CPUs, with no
+	 * association with allocation resource.
+	 *
+	 * Use ptr_ring, as it separates consumer and producer
+	 * efficiently, it a way that doesn't bounce cache-lines.
+	 *
+	 * TODO: Implement bulk return pages into this structure.
+	 */
+	struct ptr_ring ring;
+
+	void *mp_priv;
+	const struct memory_provider_ops *mp_ops;
+
+	struct xarray dma_mapped;
+
+#ifdef CONFIG_PAGE_POOL_STATS
+	/* recycle stats are per-cpu to avoid locking */
+	struct page_pool_recycle_stats __percpu *recycle_stats;
+#endif
+	atomic_t pages_state_release_cnt;
+
+	/* A page_pool is strictly tied to a single RX-queue being
+	 * protected by NAPI, due to above pp_alloc_cache. This
+	 * refcnt serves purpose is to simplify drivers error handling.
+	 */
+	refcount_t user_cnt;
+
+	u64 destroy_cnt;
+
+	/* Slow/Control-path information follows */
+	struct page_pool_params_slow slow;
+	/* User-facing fields, protected by page_pools_lock */
+	struct {
+		struct hlist_node list;
+		ktime_t detach_time;
+		u32 id;
+	} user;
+};
+
+struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
+netmem_ref page_pool_alloc_netmems(struct page_pool *pool, gfp_t gfp);
+struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
+				  unsigned int size, gfp_t gfp);
+netmem_ref page_pool_alloc_frag_netmem(struct page_pool *pool,
+				       unsigned int *offset, unsigned int size,
+				       gfp_t gfp);
+struct page_pool *page_pool_create(const struct page_pool_params *params);
+struct page_pool *page_pool_create_percpu(const struct page_pool_params *params,
+					  int cpuid);
+
+struct xdp_mem_info;
+
+#ifdef CONFIG_PAGE_POOL
+void page_pool_enable_direct_recycling(struct page_pool *pool,
+				       struct napi_struct *napi);
+void page_pool_disable_direct_recycling(struct page_pool *pool);
+void page_pool_destroy(struct page_pool *pool);
+void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
+			   const struct xdp_mem_info *mem);
+void page_pool_put_netmem_bulk(netmem_ref *data, u32 count);
+#else
+static inline void page_pool_destroy(struct page_pool *pool)
+{
+}
+
+static inline void page_pool_use_xdp_mem(struct page_pool *pool,
+					 void (*disconnect)(void *),
+					 const struct xdp_mem_info *mem)
+{
+}
+
+static inline void page_pool_put_netmem_bulk(netmem_ref *data, u32 count)
+{
+}
+#endif
+
+void page_pool_put_unrefed_netmem(struct page_pool *pool, netmem_ref netmem,
+				  unsigned int dma_sync_size,
+				  bool allow_direct);
+void page_pool_put_unrefed_page(struct page_pool *pool, struct page *page,
+				unsigned int dma_sync_size,
+				bool allow_direct);
+
+static inline bool is_page_pool_compiled_in(void)
+{
+#ifdef CONFIG_PAGE_POOL
+	return true;
+#else
+	return false;
+#endif
+}
+
+/* Caller must provide appropriate safe context, e.g. NAPI. */
+void page_pool_update_nid(struct page_pool *pool, int new_nid);
+
+#endif /* _NET_PAGE_POOL_H */