Message-ID: <ZL/fVF7WetuLgB0l@hera>
Date:   Tue, 25 Jul 2023 17:42:28 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     Yunsheng Lin <linyunsheng@...wei.com>
Cc:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alexander Lobakin <aleksander.lobakin@...el.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Wei Fang <wei.fang@....com>,
        Shenwei Wang <shenwei.wang@....com>,
        Clark Wang <xiaoning.wang@....com>,
        NXP Linux Team <linux-imx@....com>,
        Sunil Goutham <sgoutham@...vell.com>,
        Geetha sowjanya <gakula@...vell.com>,
        Subbaraya Sundeep <sbhatta@...vell.com>,
        hariprasad <hkelam@...vell.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        Felix Fietkau <nbd@....name>,
        Lorenzo Bianconi <lorenzo@...nel.org>,
        Ryder Lee <ryder.lee@...iatek.com>,
        Shayne Chen <shayne.chen@...iatek.com>,
        Sean Wang <sean.wang@...iatek.com>,
        Kalle Valo <kvalo@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        linux-rdma@...r.kernel.org, bpf@...r.kernel.org,
        linux-wireless@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH net-next v2] page_pool: split types and declarations from
 page_pool.h

Hi Yunsheng, all

On Tue, Jul 25, 2023 at 09:12:55PM +0800, Yunsheng Lin wrote:
> Split types and pure function declarations from page_pool.h
> and add them in page_pool/types.h, so that C sources can
> include page_pool.h and headers should generally only include
> page_pool/types.h as suggested by jakub.
>

Apologies for the very late replies, I was on long vacation with limited
internet access.
Yunsheng, since there's been a few mails and I lost track, this is instead of
[0] right? If so, I prefer this approach.  It looks ok on a first quick pass,
I'll have a closer look later.

[0] https://lore.kernel.org/netdev/20230714170853.866018-2-aleksander.lobakin@intel.com/

Thanks
/Ilias

> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
> Suggested-by: Jakub Kicinski <kuba@...nel.org>
> CC: Alexander Lobakin <aleksander.lobakin@...el.com>
> ---
> V2: Move from page_pool_types.h to page_pool/types.h, fix
>     some typo and alphabetic sorting.
> ---
>  MAINTAINERS                                   |   1 +
>  drivers/net/ethernet/engleder/tsnep_main.c    |   1 +
>  drivers/net/ethernet/freescale/fec_main.c     |   1 +
>  .../marvell/octeontx2/nic/otx2_common.c       |   1 +
>  .../ethernet/marvell/octeontx2/nic/otx2_pf.c  |   1 +
>  .../ethernet/mellanox/mlx5/core/en/params.c   |   1 +
>  .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |   1 +
>  drivers/net/wireless/mediatek/mt76/mt76.h     |   1 +
>  include/linux/skbuff.h                        |   2 +-
>  include/net/page_pool.h                       | 192 +----------------
>  include/net/page_pool/types.h                 | 193 ++++++++++++++++++
>  11 files changed, 206 insertions(+), 189 deletions(-)
>  create mode 100644 include/net/page_pool/types.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d0553ad37865..1dbfe7fcb10e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16016,6 +16016,7 @@ L:	netdev@...r.kernel.org
>  S:	Supported
>  F:	Documentation/networking/page_pool.rst
>  F:	include/net/page_pool.h
> +F:	include/net/page_pool_types.h
>  F:	include/trace/events/page_pool.h
>  F:	net/core/page_pool.c
>
> diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
> index 079f9f6ae21a..934b890ba2ab 100644
> --- a/drivers/net/ethernet/engleder/tsnep_main.c
> +++ b/drivers/net/ethernet/engleder/tsnep_main.c
> @@ -28,6 +28,7 @@
>  #include <linux/iopoll.h>
>  #include <linux/bpf.h>
>  #include <linux/bpf_trace.h>
> +#include <net/page_pool.h>
>  #include <net/xdp_sock_drv.h>
>
>  #define TSNEP_RX_OFFSET (max(NET_SKB_PAD, XDP_PACKET_HEADROOM) + NET_IP_ALIGN)
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 03ac7690b5c4..68b79bda632a 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -38,6 +38,7 @@
>  #include <linux/in.h>
>  #include <linux/ip.h>
>  #include <net/ip.h>
> +#include <net/page_pool.h>
>  #include <net/selftests.h>
>  #include <net/tso.h>
>  #include <linux/tcp.h>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> index 8cdd92dd9762..d4f1baf0f987 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> @@ -7,6 +7,7 @@
>
>  #include <linux/interrupt.h>
>  #include <linux/pci.h>
> +#include <net/page_pool.h>
>  #include <net/tso.h>
>  #include <linux/bitfield.h>
>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
> index 9551b422622a..8807e40b1174 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
> @@ -16,6 +16,7 @@
>  #include <linux/bpf.h>
>  #include <linux/bpf_trace.h>
>  #include <linux/bitfield.h>
> +#include <net/page_pool.h>
>
>  #include "otx2_reg.h"
>  #include "otx2_common.h"
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
> index 5ce28ff7685f..0f152f14165b 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
> @@ -6,6 +6,7 @@
>  #include "en/port.h"
>  #include "en_accel/en_accel.h"
>  #include "en_accel/ipsec.h"
> +#include <net/page_pool.h>
>  #include <net/xdp_sock_drv.h>
>
>  static u8 mlx5e_mpwrq_min_page_shift(struct mlx5_core_dev *mdev)
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
> index 40589cebb773..16038c23b7d8 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
> @@ -35,6 +35,7 @@
>  #include "en/xdp.h"
>  #include "en/params.h"
>  #include <linux/bitfield.h>
> +#include <net/page_pool.h>
>
>  int mlx5e_xdp_max_mtu(struct mlx5e_params *params, struct mlx5e_xsk_param *xsk)
>  {
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
> index 6b07b8fafec2..95c16f11d156 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt76.h
> @@ -15,6 +15,7 @@
>  #include <linux/average.h>
>  #include <linux/soc/mediatek/mtk_wed.h>
>  #include <net/mac80211.h>
> +#include <net/page_pool.h>
>  #include "util.h"
>  #include "testmode.h"
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index faaba050f843..864c51c95ac4 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -32,7 +32,7 @@
>  #include <linux/if_packet.h>
>  #include <linux/llist.h>
>  #include <net/flow.h>
> -#include <net/page_pool.h>
> +#include <net/page_pool/types.h>
>  #if IS_ENABLED(CONFIG_NF_CONNTRACK)
>  #include <linux/netfilter/nf_conntrack_common.h>
>  #endif
> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> index f1d5cc1fa13b..dd70474c67cc 100644
> --- a/include/net/page_pool.h
> +++ b/include/net/page_pool.h
> @@ -29,107 +29,9 @@
>  #ifndef _NET_PAGE_POOL_H
>  #define _NET_PAGE_POOL_H
>
> -#include <linux/mm.h> /* Needed by ptr_ring */
> -#include <linux/ptr_ring.h>
> -#include <linux/dma-direction.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_PAGE_FRAG	BIT(2) /* for page frag feature */
> -#define PP_FLAG_ALL		(PP_FLAG_DMA_MAP |\
> -				 PP_FLAG_DMA_SYNC_DEV |\
> -				 PP_FLAG_PAGE_FRAG)
> -
> -/*
> - * 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.
> - *
> - * 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.
> - */
> -#define PP_ALLOC_CACHE_SIZE	128
> -#define PP_ALLOC_CACHE_REFILL	64
> -struct pp_alloc_cache {
> -	u32 count;
> -	struct page *cache[PP_ALLOC_CACHE_SIZE];
> -};
> -
> -struct page_pool_params {
> -	unsigned int	flags;
> -	unsigned int	order;
> -	unsigned int	pool_size;
> -	int		nid;  /* Numa node id to allocate from pages from */
> -	struct device	*dev; /* device, for DMA pre-mapping purposes */
> -	struct napi_struct *napi; /* Sole consumer of pages, otherwise NULL */
> -	enum dma_data_direction dma_dir; /* DMA mapping direction */
> -	unsigned int	max_len; /* max DMA sync memory size */
> -	unsigned int	offset;  /* DMA addr offset */
> -	void (*init_callback)(struct page *page, void *arg);
> -	void *init_arg;
> -};
> -
> -#ifdef CONFIG_PAGE_POOL_STATS
> -struct page_pool_alloc_stats {
> -	u64 fast; /* fast path allocations */
> -	u64 slow; /* slow-path order 0 allocations */
> -	u64 slow_high_order; /* slow-path high order allocations */
> -	u64 empty; /* failed refills due to empty ptr ring, forcing
> -		    * slow path allocation
> -		    */
> -	u64 refill; /* allocations via successful refill */
> -	u64 waive;  /* failed refills due to numa zone mismatch */
> -};
> -
> -struct page_pool_recycle_stats {
> -	u64 cached;	/* recycling placed page in the cache. */
> -	u64 cache_full; /* cache was full */
> -	u64 ring;	/* recycling placed page back into ptr ring */
> -	u64 ring_full;	/* page was released from page-pool because
> -			 * PTR ring was full.
> -			 */
> -	u64 released_refcnt; /* page released because of elevated
> -			      * refcnt
> -			      */
> -};
> -
> -/* This struct wraps the above stats structs so users of the
> - * page_pool_get_stats API can pass a single argument when requesting the
> - * stats for the page pool.
> - */
> -struct page_pool_stats {
> -	struct page_pool_alloc_stats alloc_stats;
> -	struct page_pool_recycle_stats recycle_stats;
> -};
> -
> -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, void *stats);
> -
> -/*
> - * Drivers that wish to harvest page pool stats and report them to users
> - * (perhaps via ethtool, debugfs, or another mechanism) can allocate a
> - * struct page_pool_stats call page_pool_get_stats to get stats for the specified pool.
> - */
> -bool page_pool_get_stats(struct page_pool *pool,
> -			 struct page_pool_stats *stats);
> -#else
> +#include <net/page_pool/types.h>
>
> +#ifndef CONFIG_PAGE_POOL_STATS
>  static inline int page_pool_ethtool_stats_get_count(void)
>  {
>  	return 0;
> @@ -144,72 +46,7 @@ static inline u64 *page_pool_ethtool_stats_get(u64 *data, void *stats)
>  {
>  	return data;
>  }
> -
> -#endif
> -
> -struct page_pool {
> -	struct page_pool_params p;
> -
> -	struct delayed_work release_dw;
> -	void (*disconnect)(void *);
> -	unsigned long defer_start;
> -	unsigned long defer_warn;
> -
> -	u32 pages_state_hold_cnt;
> -	unsigned int frag_offset;
> -	struct page *frag_page;
> -	long frag_users;
> -
> -#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
> -	 * effeciently, it a way that doesn't bounce cache-lines.
> -	 *
> -	 * TODO: Implement bulk return pages into this structure.
> -	 */
> -	struct ptr_ring ring;
> -
> -#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;
> -};
> -
> -struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
>
>  static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
>  {
> @@ -218,9 +55,6 @@ static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
>  	return page_pool_alloc_pages(pool, gfp);
>  }
>
> -struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
> -				  unsigned int size, gfp_t gfp);
> -
>  static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
>  						    unsigned int *offset,
>  						    unsigned int size)
> @@ -239,20 +73,7 @@ inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool)
>  	return pool->p.dma_dir;
>  }
>
> -bool page_pool_return_skb_page(struct page *page, bool napi_safe);
> -
> -struct page_pool *page_pool_create(const struct page_pool_params *params);
> -
> -struct xdp_mem_info;
> -
> -#ifdef CONFIG_PAGE_POOL
> -void page_pool_unlink_napi(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 *),
> -			   struct xdp_mem_info *mem);
> -void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> -			     int count);
> -#else
> +#ifndef CONFIG_PAGE_POOL
>  static inline void page_pool_unlink_napi(struct page_pool *pool)
>  {
>  }
> @@ -261,6 +82,7 @@ static inline void page_pool_destroy(struct page_pool *pool)
>  {
>  }
>
> +struct xdp_mem_info;
>  static inline void page_pool_use_xdp_mem(struct page_pool *pool,
>  					 void (*disconnect)(void *),
>  					 struct xdp_mem_info *mem)
> @@ -273,10 +95,6 @@ static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,
>  }
>  #endif
>
> -void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
> -				  unsigned int dma_sync_size,
> -				  bool allow_direct);
> -
>  /* pp_frag_count represents the number of writers who can update the page
>   * either by updating skb->data or via DMA mappings for the device.
>   * We can't rely on the page refcnt for that as we don't know who might be
> @@ -385,8 +203,6 @@ static inline bool page_pool_put(struct page_pool *pool)
>  	return refcount_dec_and_test(&pool->user_cnt);
>  }
>
> -/* Caller must provide appropriate safe context, e.g. NAPI. */
> -void page_pool_update_nid(struct page_pool *pool, int new_nid);
>  static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
>  {
>  	if (unlikely(pool->p.nid != new_nid))
> diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
> new file mode 100644
> index 000000000000..1d54ba0708db
> --- /dev/null
> +++ b/include/net/page_pool/types.h
> @@ -0,0 +1,193 @@
> +/* 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>
> +
> +#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_PAGE_FRAG	BIT(2) /* for page frag feature */
> +#define PP_FLAG_ALL		(PP_FLAG_DMA_MAP |\
> +				 PP_FLAG_DMA_SYNC_DEV |\
> +				 PP_FLAG_PAGE_FRAG)
> +
> +/*
> + * 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.
> + *
> + * 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.
> + */
> +#define PP_ALLOC_CACHE_SIZE	128
> +#define PP_ALLOC_CACHE_REFILL	64
> +struct pp_alloc_cache {
> +	u32 count;
> +	struct page *cache[PP_ALLOC_CACHE_SIZE];
> +};
> +
> +struct page_pool_params {
> +	unsigned int	flags;
> +	unsigned int	order;
> +	unsigned int	pool_size;
> +	int		nid;  /* Numa node id to allocate from pages from */
> +	struct device	*dev; /* device, for DMA pre-mapping purposes */
> +	struct napi_struct *napi; /* Sole consumer of pages, otherwise NULL */
> +	enum dma_data_direction dma_dir; /* DMA mapping direction */
> +	unsigned int	max_len; /* max DMA sync memory size */
> +	unsigned int	offset;  /* DMA addr offset */
> +	void (*init_callback)(struct page *page, void *arg);
> +	void *init_arg;
> +};
> +
> +#ifdef CONFIG_PAGE_POOL_STATS
> +struct page_pool_alloc_stats {
> +	u64 fast; /* fast path allocations */
> +	u64 slow; /* slow-path order 0 allocations */
> +	u64 slow_high_order; /* slow-path high order allocations */
> +	u64 empty; /* failed refills due to empty ptr ring, forcing
> +		    * slow path allocation
> +		    */
> +	u64 refill; /* allocations via successful refill */
> +	u64 waive;  /* failed refills due to numa zone mismatch */
> +};
> +
> +struct page_pool_recycle_stats {
> +	u64 cached;	/* recycling placed page in the cache. */
> +	u64 cache_full; /* cache was full */
> +	u64 ring;	/* recycling placed page back into ptr ring */
> +	u64 ring_full;	/* page was released from page-pool because
> +			 * PTR ring was full.
> +			 */
> +	u64 released_refcnt; /* page released because of elevated
> +			      * refcnt
> +			      */
> +};
> +
> +/* This struct wraps the above stats structs so users of the
> + * page_pool_get_stats API can pass a single argument when requesting the
> + * stats for the page pool.
> + */
> +struct page_pool_stats {
> +	struct page_pool_alloc_stats alloc_stats;
> +	struct page_pool_recycle_stats recycle_stats;
> +};
> +
> +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, void *stats);
> +
> +/*
> + * Drivers that wish to harvest page pool stats and report them to users
> + * (perhaps via ethtool, debugfs, or another mechanism) can allocate a
> + * struct page_pool_stats call page_pool_get_stats to get stats for the
> + * specified pool.
> + */
> +bool page_pool_get_stats(struct page_pool *pool,
> +			 struct page_pool_stats *stats);
> +#endif
> +
> +struct page_pool {
> +	struct page_pool_params p;
> +
> +	struct delayed_work release_dw;
> +	void (*disconnect)(void *);
> +	unsigned long defer_start;
> +	unsigned long defer_warn;
> +
> +	u32 pages_state_hold_cnt;
> +	unsigned int frag_offset;
> +	struct page *frag_page;
> +	long frag_users;
> +
> +#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;
> +
> +#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;
> +};
> +
> +struct page *page_pool_alloc_pages(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);
> +bool page_pool_return_skb_page(struct page *page, bool napi_safe);
> +struct page_pool *page_pool_create(const struct page_pool_params *params);
> +
> +#ifdef CONFIG_PAGE_POOL
> +void page_pool_unlink_napi(struct page_pool *pool);
> +void page_pool_destroy(struct page_pool *pool);
> +
> +struct xdp_mem_info;
> +void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
> +			   struct xdp_mem_info *mem);
> +void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> +			     int count);
> +#endif
> +
> +void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
> +				  unsigned int dma_sync_size,
> +				  bool allow_direct);
> +
> +/* 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 */
> --
> 2.33.0
>

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