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 
ERR_PTR(long error)24 static inline void * __must_check ERR_PTR(long error)
25 {
26 	return (void *) error;
27 }
28 
PTR_ERR(__force const void * ptr)29 static inline long __must_check PTR_ERR(__force const void *ptr)
30 {
31 	return (long) ptr;
32 }
33 
IS_ERR(__force const void * ptr)34 static inline bool __must_check IS_ERR(__force const void *ptr)
35 {
36 	return IS_ERR_VALUE((unsigned long)ptr);
37 }
38 
IS_ERR_OR_NULL(__force const void * ptr)39 static 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  */
ERR_CAST(__force const void * ptr)51 static inline void * __must_check ERR_CAST(__force const void *ptr)
52 {
53 	/* cast away the const */
54 	return (void *) ptr;
55 }
56 
PTR_ERR_OR_ZERO(__force const void * ptr)57 static 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 /* Deprecated */
66 #define PTR_RET(p) PTR_ERR_OR_ZERO(p)
67 
68 #endif
69 
70 #endif /* _LINUX_ERR_H */
71