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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_ERR_H
2#define _LINUX_ERR_H
3
4#include <linux/compiler.h>
5
6#include <asm/errno.h>
7
8/*
9 * Kernel pointers have redundant information, so we can use a
10 * scheme where we can return either an error code or a dentry
11 * pointer with the same return value.
12 *
13 * This should be a per-architecture thing, to allow different
14 * error and pointer decisions.
15 */
Ralf Baechlefa798372006-07-01 04:36:25 -070016#define MAX_ERRNO 4095
17
Randy Dunlapebba5f92006-09-27 01:50:55 -070018#ifndef __ASSEMBLY__
19
Ralf Baechlefa798372006-07-01 04:36:25 -070020#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
Linus Torvalds07ab67c2005-05-19 22:43:37 -070021
Linus Torvalds1da177e2005-04-16 15:20:36 -070022static inline void *ERR_PTR(long error)
23{
24 return (void *) error;
25}
26
27static inline long PTR_ERR(const void *ptr)
28{
29 return (long) ptr;
30}
31
32static inline long IS_ERR(const void *ptr)
33{
Linus Torvalds07ab67c2005-05-19 22:43:37 -070034 return IS_ERR_VALUE((unsigned long)ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035}
36
Phil Carmody603c4ba2009-12-14 18:00:29 -080037static inline long IS_ERR_OR_NULL(const void *ptr)
38{
39 return !ptr || IS_ERR_VALUE((unsigned long)ptr);
40}
41
David Howellsd1bc8e92008-02-07 00:15:26 -080042/**
43 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
44 * @ptr: The pointer to cast.
45 *
46 * Explicitly cast an error-valued pointer to another pointer type in such a
47 * way as to make it clear that's what's going on.
48 */
49static inline void *ERR_CAST(const void *ptr)
50{
51 /* cast away the const */
52 return (void *) ptr;
53}
54
Randy Dunlapebba5f92006-09-27 01:50:55 -070055#endif
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#endif /* _LINUX_ERR_H */