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#ifndef _LINUX_ERR_H
#define _LINUX_ERR_H
#include <linux/compiler.h>
#include <linux/compat.h>
#include <linux/errno.h>
/*
* Kernel pointers have redundant information, so we can use a
* scheme where we can return either an error code or a dentry
* 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__
#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
static inline void *ERR_PTR(long error)
{
return (void *)(CONFIG_ERR_PTR_OFFSET + error);
}
static inline long PTR_ERR(const void *ptr)
{
return ((long)ptr - CONFIG_ERR_PTR_OFFSET);
}
static inline long IS_ERR(const void *ptr)
{
return IS_ERR_VALUE((unsigned long)PTR_ERR(ptr));
}
static inline bool IS_ERR_OR_NULL(const void *ptr)
{
return !ptr || IS_ERR_VALUE((unsigned long)PTR_ERR(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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