#ifndef __TRACE_STAT_H
  #define __TRACE_STAT_H
  
  #include <linux/seq_file.h>
  
  /*
   * If you want to provide a stat file (one-shot statistics), fill
   * an iterator with stat_start/stat_next and a stat_show callbacks.
   * The others callbacks are optional.
   */
  struct tracer_stat {
  	/* The name of your stat file */
  	const char		*name;
  	/* Iteration over statistic entries */

  	void			*(*stat_start)(struct tracer_stat *trace);

  	void			*(*stat_next)(void *prev, int idx);
  	/* Compare two entries for stats sorting */
  	int			(*stat_cmp)(void *p1, void *p2);
  	/* Print a stat entry */
  	int			(*stat_show)(struct seq_file *s, void *p);

  	/* Release an entry */
  	void			(*stat_release)(void *stat);

  	/* Print the headers of your stat entries */
  	int			(*stat_headers)(struct seq_file *s);
  };
  
  /*
   * Destroy or create a stat file
   */
  extern int register_stat_tracer(struct tracer_stat *trace);
  extern void unregister_stat_tracer(struct tracer_stat *trace);
  
  #endif /* __TRACE_STAT_H */