[linux-2.6-block.git] / include / linux / err.h

#ifndef _LINUX_ERR_H
#define _LINUX_ERR_H

#include <linux/compiler.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 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 *) error;
}

static inline long PTR_ERR(const void *ptr)
{
	return (long) ptr;
}

static inline long IS_ERR(const void *ptr)
{
	return IS_ERR_VALUE((unsigned long)ptr);
}

static inline long IS_ERR_OR_NULL(const void *ptr)
{
	return !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 *ERR_CAST(const void *ptr)
{
	/* cast away the const */
	return (void *) ptr;
}

#endif

#endif /* _LINUX_ERR_H */
Commit	Line	Data
1da177e4 LT	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	*/
fa79837d RB	16	#define MAX_ERRNO 4095
fa79837d RB	17
ebba5f9f RD	18	#ifndef __ASSEMBLY__
ebba5f9f RD	19
fa79837d	20	#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
07ab67c8	21
1da177e4 LT	22	static inline void *ERR_PTR(long error)
	23	{
	24	return (void *) error;
	25	}
	26
	27	static inline long PTR_ERR(const void *ptr)
	28	{
	29	return (long) ptr;
	30	}
	31
	32	static inline long IS_ERR(const void *ptr)
	33	{
07ab67c8	34	return IS_ERR_VALUE((unsigned long)ptr);
1da177e4 LT	35	}
1da177e4 LT	36
603c4ba9 PC	37	static inline long IS_ERR_OR_NULL(const void *ptr)
	38	{
	39	return !ptr \|\| IS_ERR_VALUE((unsigned long)ptr);
	40	}
	41
d1bc8e95 DH	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 ERR_CAST(const void ptr)
	50	{
	51	/* cast away the const */
	52	return (void *) ptr;
	53	}
	54
ebba5f9f RD	55	#endif
ebba5f9f RD	56
1da177e4	57	#endif /* _LINUX_ERR_H */