LXR linux/include/linux/err.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_ERR_H
   3#define _LINUX_ERR_H
   4
   5#include <linux/compiler.h>
   6#include <linux/types.h>
   7
   8#include <asm/errno.h>
   9
  10/*
  11 * Kernel pointers have redundant information, so we can use a
  12 * scheme where we can return either an error code or a normal
  13 * pointer with the same return value.
  14 *
  15 * This should be a per-architecture thing, to allow different
  16 * error and pointer decisions.
  17 */
  18#define MAX_ERRNO       4095
  19
  20#ifndef __ASSEMBLY__
  21
  22#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
  23
  24static inline void * __must_check ERR_PTR(long error)
  25{
  26        return (void *) error;
  27}
  28
  29static inline long __must_check PTR_ERR(__force const void *ptr)
  30{
  31        return (long) ptr;
  32}
  33
  34static inline bool __must_check IS_ERR(__force const void *ptr)
  35{
  36        return IS_ERR_VALUE((unsigned long)ptr);
  37}
  38
  39static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
  40{
  41        return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
  42}
  43
  44/**
  45 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
  46 * @ptr: The pointer to cast.
  47 *
  48 * Explicitly cast an error-valued pointer to another pointer type in such a
  49 * way as to make it clear that's what's going on.
  50 */
  51static inline void * __must_check ERR_CAST(__force const void *ptr)
  52{
  53        /* cast away the const */
  54        return (void *) ptr;
  55}
  56
  57static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
  58{
  59        if (IS_ERR(ptr))
  60                return PTR_ERR(ptr);
  61        else
  62                return 0;
  63}
  64
  65#endif
  66
  67#endif /* _LINUX_ERR_H */
  68