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lttng: offset alignment header

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Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Mathieu Desnoyers
2011-11-28 07:42:12 -05:00
committed by Greg Kroah-Hartman
parent a643061cb8
commit 2d31597d37
1 changed files with 61 additions and 0 deletions
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61
drivers/staging/lttng/lib/align.h Normal file
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#ifndef _LTTNG_ALIGN_H
#define _LTTNG_ALIGN_H
/*
* lib/align.h
*
* (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* Dual LGPL v2.1/GPL v2 license.
*/
#ifdef __KERNEL__
#include <linux/types.h>
#include "bug.h"
#define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
#define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask))
#define PTR_ALIGN_FLOOR(p, a) \
((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
/*
* Align pointer on natural object alignment.
*/
#define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj)))
#define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))
/**
* offset_align - Calculate the offset needed to align an object on its natural
* alignment towards higher addresses.
* @align_drift: object offset from an "alignment"-aligned address.
* @alignment: natural object alignment. Must be non-zero, power of 2.
*
* Returns the offset that must be added to align towards higher
* addresses.
*/
#define offset_align(align_drift, alignment) \
({ \
BUILD_RUNTIME_BUG_ON((alignment) == 0 \
|| ((alignment) & ((alignment) - 1))); \
(((alignment) - (align_drift)) & ((alignment) - 1)); \
})
/**
* offset_align_floor - Calculate the offset needed to align an object
* on its natural alignment towards lower addresses.
* @align_drift: object offset from an "alignment"-aligned address.
* @alignment: natural object alignment. Must be non-zero, power of 2.
*
* Returns the offset that must be substracted to align towards lower addresses.
*/
#define offset_align_floor(align_drift, alignment) \
({ \
BUILD_RUNTIME_BUG_ON((alignment) == 0 \
|| ((alignment) & ((alignment) - 1))); \
(((align_drift) - (alignment)) & ((alignment) - 1); \
})
#endif /* __KERNEL__ */
#endif