| 1 | #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 | */ |
| 16 | #define MAX_ERRNO 4095 |
| 17 | |
| 18 | #ifndef __ASSEMBLY__ |
| 19 | |
| 20 | #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) |
| 21 | |
| 22 | static inline void * __must_check ERR_PTR(long error) |
| 23 | { |
| 24 | return (void *) error; |
| 25 | } |
| 26 | |
| 27 | static inline long __must_check PTR_ERR(const void *ptr) |
| 28 | { |
| 29 | return (long) ptr; |
| 30 | } |
| 31 | |
| 32 | static inline long __must_check IS_ERR(const void *ptr) |
| 33 | { |
| 34 | return IS_ERR_VALUE((unsigned long)ptr); |
| 35 | } |
| 36 | |
| 37 | static inline long __must_check IS_ERR_OR_NULL(const void *ptr) |
| 38 | { |
| 39 | return !ptr || IS_ERR_VALUE((unsigned long)ptr); |
| 40 | } |
| 41 | |
| 42 | /** |
| 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 | */ |
| 49 | static inline void * __must_check ERR_CAST(const void *ptr) |
| 50 | { |
| 51 | /* cast away the const */ |
| 52 | return (void *) ptr; |
| 53 | } |
| 54 | |
| 55 | static 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 | |
| 63 | #endif |
| 64 | |
| 65 | #endif /* _LINUX_ERR_H */ |