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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
Jani Nikulae47103b2010-05-24 14:33:00 -070022static inline void * __must_check ERR_PTR(long error)
Linus Torvalds1da177e2005-04-16 15:20:36 -070023{
24 return (void *) error;
25}
26
Jani Nikulae47103b2010-05-24 14:33:00 -070027static inline long __must_check PTR_ERR(const void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070028{
29 return (long) ptr;
30}
31
Jani Nikulae47103b2010-05-24 14:33:00 -070032static inline long __must_check IS_ERR(const void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070033{
Linus Torvalds07ab67c2005-05-19 22:43:37 -070034 return IS_ERR_VALUE((unsigned long)ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035}
36
Jani Nikulae47103b2010-05-24 14:33:00 -070037static inline long __must_check IS_ERR_OR_NULL(const void *ptr)
Phil Carmody603c4ba2009-12-14 18:00:29 -080038{
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 */
Jani Nikulae47103b2010-05-24 14:33:00 -070049static inline void * __must_check ERR_CAST(const void *ptr)
David Howellsd1bc8e92008-02-07 00:15:26 -080050{
51 /* cast away the const */
52 return (void *) ptr;
53}
54
Uwe Kleine-Königfa9ee9c2011-03-22 16:34:05 -070055static inline int __must_check PTR_RET(const void *ptr)
56{
57 if (IS_ERR(ptr))
58 return PTR_ERR(ptr);
59 else
60 return 0;
61}
62
Randy Dunlapebba5f92006-09-27 01:50:55 -070063#endif
64
Linus Torvalds1da177e2005-04-16 15:20:36 -070065#endif /* _LINUX_ERR_H */