#ifndef __LINUX_CPU_RMAP_H
  #define __LINUX_CPU_RMAP_H

  /*
   * cpu_rmap.c: CPU affinity reverse-map support
   * Copyright 2011 Solarflare Communications Inc.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation, incorporated herein by reference.
   */
  
  #include <linux/cpumask.h>
  #include <linux/gfp.h>
  #include <linux/slab.h>

  #include <linux/kref.h>

  
  /**
   * struct cpu_rmap - CPU affinity reverse-map

   * @refcount: kref for object

   * @size: Number of objects to be reverse-mapped
   * @used: Number of objects added
   * @obj: Pointer to array of object pointers
   * @near: For each CPU, the index and distance to the nearest object,
   *      based on affinity masks
   */
  struct cpu_rmap {

  	struct kref	refcount;

  	u16		size, used;
  	void		**obj;
  	struct {
  		u16	index;
  		u16	dist;
  	}		near[0];
  };
  #define CPU_RMAP_DIST_INF 0xffff
  
  extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);

  extern int cpu_rmap_put(struct cpu_rmap *rmap);

  
  extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
  extern int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
  			   const struct cpumask *affinity);
  
  static inline u16 cpu_rmap_lookup_index(struct cpu_rmap *rmap, unsigned int cpu)
  {
  	return rmap->near[cpu].index;
  }
  
  static inline void *cpu_rmap_lookup_obj(struct cpu_rmap *rmap, unsigned int cpu)
  {
  	return rmap->obj[rmap->near[cpu].index];
  }

  /**
   * alloc_irq_cpu_rmap - allocate CPU affinity reverse-map for IRQs
   * @size: Number of objects to be mapped
   *
   * Must be called in process context.
   */
  static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size)
  {
  	return alloc_cpu_rmap(size, GFP_KERNEL);
  }
  extern void free_irq_cpu_rmap(struct cpu_rmap *rmap);
  
  extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq);

  #endif /* __LINUX_CPU_RMAP_H */