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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_ERR_H
#define _LINUX_ERR_H
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/errno.h>
/*
* Kernel pointers have redundant information, so we can use a
* scheme where we can return either an error code or a normal
* pointer with the same return value.
*
* This should be a per-architecture thing, to allow different
* error and pointer decisions.
*/
#define MAX_ERRNO 4095
#ifndef __ASSEMBLY__
/**
* IS_ERR_VALUE - Detect an error pointer.
* @x: The pointer to check.
*
* Like IS_ERR(), but does not generate a compiler warning if result is unused.
*/
#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
/**
* ERR_PTR - Create an error pointer.
* @error: A negative error code.
*
* Encodes @error into a pointer value. Users should consider the result
* opaque and not assume anything about how the error is encoded.
*
* Return: A pointer with @error encoded within its value.
*/
static inline void * __must_check ERR_PTR(long error)
{
return (void *) error;
}
/* Return the pointer in the percpu address space. */
#define ERR_PTR_PCPU(error) ((void __percpu *)(unsigned long)ERR_PTR(error))
/**
* PTR_ERR - Extract the error code from an error pointer.
* @ptr: An error pointer.
* Return: The error code within @ptr.
*/
static inline long __must_check PTR_ERR(__force const void *ptr)
{
return (long) ptr;
}
/* Read an error pointer from the percpu address space. */
#define PTR_ERR_PCPU(ptr) (PTR_ERR((const void *)(__force const unsigned long)(ptr)))
/**
* IS_ERR - Detect an error pointer.
* @ptr: The pointer to check.
* Return: true if @ptr is an error pointer, false otherwise.
*/
static inline bool __must_check IS_ERR(__force const void *ptr)
{
return IS_ERR_VALUE((unsigned long)ptr);
}
/* Read an error pointer from the percpu address space. */
#define IS_ERR_PCPU(ptr) (IS_ERR((const void *)(__force const unsigned long)(ptr)))
/**
* IS_ERR_OR_NULL - Detect an error pointer or a null pointer.
* @ptr: The pointer to check.
*
* Like IS_ERR(), but also returns true for a null pointer.
*/
static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
{
return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
}
/**
* ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
* @ptr: The pointer to cast.
*
* Explicitly cast an error-valued pointer to another pointer type in such a
* way as to make it clear that's what's going on.
*/
static inline void * __must_check ERR_CAST(__force const void *ptr)
{
/* cast away the const */
return (void *) ptr;
}
/**
* PTR_ERR_OR_ZERO - Extract the error code from a pointer if it has one.
* @ptr: A potential error pointer.
*
* Convenience function that can be used inside a function that returns
* an error code to propagate errors received as error pointers.
* For example, ``return PTR_ERR_OR_ZERO(ptr);`` replaces:
*
* .. code-block:: c
*
* if (IS_ERR(ptr))
* return PTR_ERR(ptr);
* else
* return 0;
*
* Return: The error code within @ptr if it is an error pointer; 0 otherwise.
*/
static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
{
if (IS_ERR(ptr))
return PTR_ERR(ptr);
else
return 0;
}
#endif
#endif /* _LINUX_ERR_H */
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