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1#ifndef _LINUX_ERR_H
2#define _LINUX_ERR_H
3
4#include <linux/compiler.h>
5#include <linux/compat.h>
6
7#include <linux/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 dentry
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 *ERR_PTR(long error)
24{
25 return (void *)(CONFIG_ERR_PTR_OFFSET + error);
26}
27
28static inline long PTR_ERR(const void *ptr)
29{
30 return ((long)ptr - CONFIG_ERR_PTR_OFFSET);
31}
32
33static inline long IS_ERR(const void *ptr)
34{
35 return IS_ERR_VALUE((unsigned long)PTR_ERR(ptr));
36}
37
38static inline bool IS_ERR_OR_NULL(const void *ptr)
39{
40 return !ptr || IS_ERR_VALUE((unsigned long)PTR_ERR(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
56#endif
57
58#endif /* _LINUX_ERR_H */