| 1 | #ifndef _LINUX_ERR_H |
| 2 | #define _LINUX_ERR_H |
| 3 | |
| 4 | #include <linux/compiler.h> |
| 5 | #include <linux/types.h> |
| 6 | |
| 7 | #include <asm/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 normal |
| 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 | |
| 23 | static inline void * __must_check ERR_PTR(long error) |
| 24 | { |
| 25 | return (void *) error; |
| 26 | } |
| 27 | |
| 28 | static inline long __must_check PTR_ERR(__force const void *ptr) |
| 29 | { |
| 30 | return (long) ptr; |
| 31 | } |
| 32 | |
| 33 | static inline bool __must_check IS_ERR(__force const void *ptr) |
| 34 | { |
| 35 | return IS_ERR_VALUE((unsigned long)ptr); |
| 36 | } |
| 37 | |
| 38 | static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr) |
| 39 | { |
| 40 | return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)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 | */ |
| 50 | static inline void * __must_check ERR_CAST(__force const void *ptr) |
| 51 | { |
| 52 | /* cast away the const */ |
| 53 | return (void *) ptr; |
| 54 | } |
| 55 | |
| 56 | static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) |
| 57 | { |
| 58 | if (IS_ERR(ptr)) |
| 59 | return PTR_ERR(ptr); |
| 60 | else |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | /* Deprecated */ |
| 65 | #define PTR_RET(p) PTR_ERR_OR_ZERO(p) |
| 66 | |
| 67 | #endif |
| 68 | |
| 69 | #endif /* _LINUX_ERR_H */ |