/*
   * 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, 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 */