| 1 |
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| 2 | #ifndef _LINUX_ERR_H
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| 3 | #define _LINUX_ERR_H
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| 4 |
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| 5 | #include <linux/compiler.h>
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| 6 | #include <linux/types.h>
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| 7 |
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| 8 | #include <asm/errno.h>
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| 9 |
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| 10 | |
| 11 | * Kernel pointers have redundant information, so we can use a
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| 12 | * scheme where we can return either an error code or a normal
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| 13 | * pointer with the same return value.
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| 14 | *
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| 15 | * This should be a per-architecture thing, to allow different
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| 16 | * error and pointer decisions.
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| 17 |
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| 18 | #define MAX_ERRNO 4095
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| 19 |
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| 20 | #ifndef __ASSEMBLY__
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| 21 |
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| 22 | |
| 23 | * IS_ERR_VALUE - Detect an error pointer.
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| 24 | * @x: The pointer to check.
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| 25 | *
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| 26 | * Like IS_ERR(), but does not generate a compiler warning if result is unused.
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| 27 |
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| 28 | #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
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| 29 |
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| 30 | |
| 31 | * ERR_PTR - Create an error pointer.
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| 32 | * @error: A negative error code.
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| 33 | *
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| 34 | * Encodes @error into a pointer value. Users should consider the result
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| 35 | * opaque and not assume anything about how the error is encoded.
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| 36 | *
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| 37 | * Return: A pointer with @error encoded within its value.
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| 38 |
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| 39 | static inline void * __must_check ERR_PTR(long error)
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| 40 | {
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| 41 | return (void *) error;
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| 42 | }
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| 43 |
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| 44 | |
| 45 | * PTR_ERR - Extract the error code from an error pointer.
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| 46 | * @ptr: An error pointer.
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| 47 | * Return: The error code within @ptr.
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| 48 |
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| 49 | static inline long __must_check PTR_ERR(__force const void *ptr)
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| 50 | {
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| 51 | return (long) ptr;
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| 52 | }
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| 53 |
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| 54 | |
| 55 | * IS_ERR - Detect an error pointer.
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| 56 | * @ptr: The pointer to check.
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| 57 | * Return: true if @ptr is an error pointer, false otherwise.
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| 58 |
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| 59 | static inline bool __must_check IS_ERR(__force const void *ptr)
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| 60 | {
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| 61 | return IS_ERR_VALUE((unsigned long)ptr);
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| 62 | }
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| 63 |
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| 64 | |
| 65 | * IS_ERR_OR_NULL - Detect an error pointer or a null pointer.
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| 66 | * @ptr: The pointer to check.
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| 67 | *
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| 68 | * Like IS_ERR(), but also returns true for a null pointer.
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| 69 |
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| 70 | static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
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| 71 | {
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| 72 | return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
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| 73 | }
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| 74 |
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| 75 | |
| 76 | * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
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| 77 | * @ptr: The pointer to cast.
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| 78 | *
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| 79 | * Explicitly cast an error-valued pointer to another pointer type in such a
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| 80 | * way as to make it clear that's what's going on.
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| 81 |
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| 82 | static inline void * __must_check ERR_CAST(__force const void *ptr)
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| 83 | {
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| 84 |
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| 85 | return (void *) ptr;
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| 86 | }
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| 87 |
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| 88 | |
| 89 | * PTR_ERR_OR_ZERO - Extract the error code from a pointer if it has one.
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| 90 | * @ptr: A potential error pointer.
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| 91 | *
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| 92 | * Convenience function that can be used inside a function that returns
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| 93 | * an error code to propagate errors received as error pointers.
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| 94 | * For example, ``return PTR_ERR_OR_ZERO(ptr);`` replaces:
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| 95 | *
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| 96 | * .. code-block:: c
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| 97 | *
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| 98 | * if (IS_ERR(ptr))
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| 99 | * return PTR_ERR(ptr);
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| 100 | * else
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| 101 | * return 0;
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| 102 | *
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| 103 | * Return: The error code within @ptr if it is an error pointer; 0 otherwise.
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| 104 |
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| 105 | static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
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| 106 | {
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| 107 | if (IS_ERR(ptr))
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| 108 | return PTR_ERR(ptr);
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| 109 | else
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| 110 | return 0;
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| 111 | }
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| 112 |
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| 113 | #endif
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| 114 |
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| 115 | #endif
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