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

source code of linux/include/linux/err.h