/*
   * Copyright (c) 2006-2007 Silicon Graphics, Inc.
   * All Rights Reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #ifndef __XFS_MRU_CACHE_H__
  #define __XFS_MRU_CACHE_H__
  
  
  /* Function pointer type for callback to free a client's data pointer. */
  typedef void (*xfs_mru_cache_free_func_t)(unsigned long, void*);
  
  typedef struct xfs_mru_cache
  {
  	struct radix_tree_root	store;     /* Core storage data structure.  */
  	struct list_head	*lists;    /* Array of lists, one per grp.  */
  	struct list_head	reap_list; /* Elements overdue for reaping. */
  	spinlock_t		lock;      /* Lock to protect this struct.  */
  	unsigned int		grp_count; /* Number of discrete groups.    */
  	unsigned int		grp_time;  /* Time period spanned by grps.  */
  	unsigned int		lru_grp;   /* Group containing time zero.   */
  	unsigned long		time_zero; /* Time first element was added. */

  	xfs_mru_cache_free_func_t free_func; /* Function pointer for freeing. */
  	struct delayed_work	work;      /* Workqueue data for reaping.   */

  	unsigned int		queued;	   /* work has been queued */

  } xfs_mru_cache_t;
  
  int xfs_mru_cache_init(void);
  void xfs_mru_cache_uninit(void);
  int xfs_mru_cache_create(struct xfs_mru_cache **mrup, unsigned int lifetime_ms,
  			     unsigned int grp_count,
  			     xfs_mru_cache_free_func_t free_func);

  void xfs_mru_cache_destroy(struct xfs_mru_cache *mru);
  int xfs_mru_cache_insert(struct xfs_mru_cache *mru, unsigned long key,
  				void *value);
  void * xfs_mru_cache_remove(struct xfs_mru_cache *mru, unsigned long key);
  void xfs_mru_cache_delete(struct xfs_mru_cache *mru, unsigned long key);
  void *xfs_mru_cache_lookup(struct xfs_mru_cache *mru, unsigned long key);

  void xfs_mru_cache_done(struct xfs_mru_cache *mru);
  
  #endif /* __XFS_MRU_CACHE_H__ */