mempool.h

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/*
 * memory buffer pool support
 */
#ifndef _LINUX_MEMPOOL_H
#define _LINUX_MEMPOOL_H

#include <linux/wait.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_s {
    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;

extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
            mempool_free_t *free_fn, void *pool_data);
extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
            mempool_free_t *free_fn, void *pool_data,
            gfp_t gfp_mask, int nid);

extern int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask);
extern void mempool_destroy(mempool_t *pool);
extern void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask);
extern void mempool_free(void *element, mempool_t *pool);

/*
 * A mempool_alloc_t and mempool_free_t that get the memory from
 * a slab that is passed in through pool_data.
 */
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data);
void mempool_free_slab(void *element, void *pool_data);
static inline mempool_t *
mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
{
    return 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);
static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
{
    return mempool_create(min_nr, mempool_kmalloc, mempool_kfree,
                  (void *) 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);
static inline mempool_t *mempool_create_page_pool(int min_nr, int order)
{
    return mempool_create(min_nr, mempool_alloc_pages, mempool_free_pages,
                  (void *)(long)order);
}

#endif /* _LINUX_MEMPOOL_H */