linux/include/linux/mempool.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * memory buffer pool support
 */
#ifndef _LINUX_MEMPOOL_H
#define _LINUX_MEMPOOL_H

#include <linux/sched.h>
#include <linux/alloc_tag.h>
#include <linux/wait.h>
#include <linux/compiler.h>

struct kmem_cache;

typedef void * (mempool_alloc_t)(gfp_t gfp_mask, void *pool_data);
typedef void (mempool_free_t)(void *element, void *pool_data);

typedef struct mempool {
	spinlock_t lock;
	int min_nr;		/* nr of elements at *elements */
	int curr_nr;		/* Current nr of elements at *elements */
	void **elements;

	void *pool_data;
	mempool_alloc_t *alloc;
	mempool_free_t *free;
	wait_queue_head_t wait;
} mempool_t;

static inline bool mempool_initialized(struct mempool *pool)
{
	return pool->elements != NULL;
}

static inline bool mempool_is_saturated(struct mempool *pool)
{
	return READ_ONCE(pool->curr_nr) >= pool->min_nr;
}

void mempool_exit(struct mempool *pool);
int mempool_init_node(struct mempool *pool, int min_nr,
		mempool_alloc_t *alloc_fn, mempool_free_t *free_fn,
		void *pool_data, gfp_t gfp_mask, int node_id);
int mempool_init_noprof(struct mempool *pool, int min_nr,
		mempool_alloc_t *alloc_fn, mempool_free_t *free_fn,
		void *pool_data);
#define mempool_init(...)						\
	alloc_hooks(mempool_init_noprof(__VA_ARGS__))

struct mempool *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
		mempool_free_t *free_fn, void *pool_data);
struct mempool *mempool_create_node_noprof(int min_nr,
		mempool_alloc_t *alloc_fn, mempool_free_t *free_fn,
		void *pool_data, gfp_t gfp_mask, int nid);
#define mempool_create_node(...)					\
	alloc_hooks(mempool_create_node_noprof(__VA_ARGS__))

#define mempool_create(_min_nr, _alloc_fn, _free_fn, _pool_data)	\
	mempool_create_node(_min_nr, _alloc_fn, _free_fn, _pool_data,	\
			    GFP_KERNEL, NUMA_NO_NODE)

int mempool_resize(struct mempool *pool, int new_min_nr);
void mempool_destroy(struct mempool *pool);

void *mempool_alloc_noprof(struct mempool *pool, gfp_t gfp_mask) __malloc;
#define mempool_alloc(...)						\
	alloc_hooks(mempool_alloc_noprof(__VA_ARGS__))
int mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,
		unsigned int count);
#define mempool_alloc_bulk(...)						\
	alloc_hooks(mempool_alloc_bulk_noprof(__VA_ARGS__))

/*
 * Allocate a new element without dipping into the pool's reserves or
 * waiting.  Returns NULL on failure.
 */
#define mempool_alloc_noreserve(_pool, _gfp)				\
	alloc_hooks((_pool)->alloc(_gfp, (_pool)->pool_data))

void *mempool_alloc_preallocated(struct mempool *pool) __malloc;
void mempool_free(void *element, struct mempool *pool);
unsigned int mempool_free_bulk(struct mempool *pool, void **elem,
		unsigned int count);

/*
 * A mempool_alloc_t and mempool_free_t that get the memory from
 * a slab cache that is passed in through pool_data.
 * Note: the slab cache may not have a ctor function.
 */
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data);
void mempool_free_slab(void *element, void *pool_data);

#define mempool_init_slab_pool(_pool, _min_nr, _kc)			\
	mempool_init(_pool, (_min_nr), mempool_alloc_slab, mempool_free_slab, (void *)(_kc))
#define mempool_create_slab_pool(_min_nr, _kc)			\
	mempool_create((_min_nr), mempool_alloc_slab, mempool_free_slab, (void *)(_kc))

/*
 * a mempool_alloc_t and a mempool_free_t to kmalloc and kfree the
 * amount of memory specified by pool_data
 */
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data);
void mempool_kfree(void *element, void *pool_data);

#define mempool_init_kmalloc_pool(_pool, _min_nr, _size)		\
	mempool_init(_pool, (_min_nr), mempool_kmalloc, mempool_kfree,	\
		     (void *)(unsigned long)(_size))
#define mempool_create_kmalloc_pool(_min_nr, _size)			\
	mempool_create((_min_nr), mempool_kmalloc, mempool_kfree,	\
		       (void *)(unsigned long)(_size))

/*
 * A mempool_alloc_t and mempool_free_t for a simple page allocator that
 * allocates pages of the order specified by pool_data
 */
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data);
void mempool_free_pages(void *element, void *pool_data);

#define mempool_init_page_pool(_pool, _min_nr, _order)			\
	mempool_init(_pool, (_min_nr), mempool_alloc_pages,		\
		     mempool_free_pages, (void *)(long)(_order))
#define mempool_create_page_pool(_min_nr, _order)			\
	mempool_create((_min_nr), mempool_alloc_pages,			\
		       mempool_free_pages, (void *)(long)(_order))

#endif /* _LINUX_MEMPOOL_H */