LXR linux/include/linux/dcookies.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * dcookies.h
   4 *
   5 * Persistent cookie-path mappings
   6 *
   7 * Copyright 2002 John Levon <levon@movementarian.org>
   8 */
   9
  10#ifndef DCOOKIES_H
  11#define DCOOKIES_H
  12 
  13
  14#ifdef CONFIG_PROFILING
  15 
  16#include <linux/dcache.h>
  17#include <linux/types.h>
  18 
  19struct dcookie_user;
  20struct path;
  21 
  22/**
  23 * dcookie_register - register a user of dcookies
  24 *
  25 * Register as a dcookie user. Returns %NULL on failure.
  26 */
  27struct dcookie_user * dcookie_register(void);
  28
  29/**
  30 * dcookie_unregister - unregister a user of dcookies
  31 *
  32 * Unregister as a dcookie user. This may invalidate
  33 * any dcookie values returned from get_dcookie().
  34 */
  35void dcookie_unregister(struct dcookie_user * user);
  36  
  37/**
  38 * get_dcookie - acquire a dcookie
  39 *
  40 * Convert the given dentry/vfsmount pair into
  41 * a cookie value.
  42 *
  43 * Returns -EINVAL if no living task has registered as a
  44 * dcookie user.
  45 *
  46 * Returns 0 on success, with *cookie filled in
  47 */
  48int get_dcookie(const struct path *path, unsigned long *cookie);
  49
  50#else
  51
  52static inline struct dcookie_user * dcookie_register(void)
  53{
  54        return NULL;
  55}
  56
  57static inline void dcookie_unregister(struct dcookie_user * user)
  58{
  59        return;
  60}
  61
  62static inline int get_dcookie(const struct path *path, unsigned long *cookie)
  63{
  64        return -ENOSYS;
  65}
  66
  67#endif /* CONFIG_PROFILING */
  68
  69#endif /* DCOOKIES_H */
  70