LXR linux/include/linux/err.h

   1#ifndef _LINUX_ERR_H
   2#define _LINUX_ERR_H
   3
   4#include <linux/compiler.h>
   5#include <linux/types.h>
   6
   7#include <asm/errno.h>
   8
   9/*
  10 * Kernel pointers have redundant information, so we can use a
  11 * scheme where we can return either an error code or a normal
  12 * pointer with the same return value.
  13 *
  14 * This should be a per-architecture thing, to allow different
  15 * error and pointer decisions.
  16 */
  17#define MAX_ERRNO       4095
  18
  19#ifndef __ASSEMBLY__
  20
  21#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
  22
  23static inline void * __must_check ERR_PTR(long error)
  24{
  25        return (void *) error;
  26}
  27
  28static inline long __must_check PTR_ERR(__force const void *ptr)
  29{
  30        return (long) ptr;
  31}
  32
  33static inline bool __must_check IS_ERR(__force const void *ptr)
  34{
  35        return IS_ERR_VALUE((unsigned long)ptr);
  36}
  37
  38static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
  39{
  40        return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
  41}
  42
  43/**
  44 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
  45 * @ptr: The pointer to cast.
  46 *
  47 * Explicitly cast an error-valued pointer to another pointer type in such a
  48 * way as to make it clear that's what's going on.
  49 */
  50static inline void * __must_check ERR_CAST(__force const void *ptr)
  51{
  52        /* cast away the const */
  53        return (void *) ptr;
  54}
  55
  56static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
  57{
  58        if (IS_ERR(ptr))
  59                return PTR_ERR(ptr);
  60        else
  61                return 0;
  62}
  63
  64/* Deprecated */
  65#define PTR_RET(p) PTR_ERR_OR_ZERO(p)
  66
  67#endif
  68
  69#endif /* _LINUX_ERR_H */
  70