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/types.h>
  16
  17 struct dcookie_user;
  18
  19 /**
  20  * dcookie_register - register a user of dcookies
  21  *
  22  * Register as a dcookie user. Returns %NULL on failure.
  23  */
  24 struct dcookie_user * dcookie_register(void);
  25
  26 /**
  27  * dcookie_unregister - unregister a user of dcookies
  28  *
  29  * Unregister as a dcookie user. This may invalidate
  30  * any dcookie values returned from get_dcookie().
  31  */
  32 void dcookie_unregister(struct dcookie_user * user);
  33
  34 /**
  35  * get_dcookie - acquire a dcookie
  36  *
  37  * Convert the given dentry/vfsmount pair into
  38  * a cookie value.
  39  *
  40  * Returns -EINVAL if no living task has registered as a
  41  * dcookie user.
  42  *
  43  * Returns 0 on success, with *cookie filled in
  44  */
  45 int get_dcookie(struct dentry * dentry, struct vfsmount * vfsmnt,
  46         unsigned long * cookie);
  47
  48 #else
  49
  50 static inline struct dcookie_user * dcookie_register(void)
  51 {
  52         return NULL;
  53 }
  54
  55 static inline void dcookie_unregister(struct dcookie_user * user)
  56 {
  57         return;
  58 }
  59
  60 static inline int get_dcookie(struct dentry * dentry,
  61         struct vfsmount * vfsmnt, unsigned long * cookie)
  62 {
  63         return -ENOSYS;
  64 }
  65
  66 #endif /* CONFIG_PROFILING */
  67
  68 #endif /* DCOOKIES_H */