LXR linux/include/linux/dcookies.h

   1/*
   2 * dcookies.h
   3 *
   4 * Persistent cookie-path mappings
   5 *
   6 * Copyright 2002 John Levon <levon@movementarian.org>
   7 */
   8
   9#ifndef DCOOKIES_H
  10#define DCOOKIES_H
  11 
  12
  13#ifdef CONFIG_PROFILING
  14 
  15#include <linux/dcache.h>
  16#include <linux/types.h>
  17 
  18struct dcookie_user;
  19struct path;
  20 
  21/**
  22 * dcookie_register - register a user of dcookies
  23 *
  24 * Register as a dcookie user. Returns %NULL on failure.
  25 */
  26struct dcookie_user * dcookie_register(void);
  27
  28/**
  29 * dcookie_unregister - unregister a user of dcookies
  30 *
  31 * Unregister as a dcookie user. This may invalidate
  32 * any dcookie values returned from get_dcookie().
  33 */
  34void dcookie_unregister(struct dcookie_user * user);
  35  
  36/**
  37 * get_dcookie - acquire a dcookie
  38 *
  39 * Convert the given dentry/vfsmount pair into
  40 * a cookie value.
  41 *
  42 * Returns -EINVAL if no living task has registered as a
  43 * dcookie user.
  44 *
  45 * Returns 0 on success, with *cookie filled in
  46 */
  47int get_dcookie(struct path *path, unsigned long *cookie);
  48
  49#else
  50
  51static inline struct dcookie_user * dcookie_register(void)
  52{
  53        return NULL;
  54}
  55
  56static inline void dcookie_unregister(struct dcookie_user * user)
  57{
  58        return;
  59}
  60
  61static inline int get_dcookie(struct path *path, unsigned long *cookie)
  62{
  63        return -ENOSYS;
  64}
  65
  66#endif /* CONFIG_PROFILING */
  67
  68#endif /* DCOOKIES_H */
  69