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