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yaml
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r: 281152
b: refs/heads/master
c: 2d31597
h: refs/heads/master
v: v3
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Mathieu Desnoyers authored and Greg Kroah-Hartman committed Nov 29, 2011
1 parent cc7547b commit 580c88f
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: a643061cb861ebb18e0292b7510dd9879b598ae0
refs/heads/master: 2d31597d37ec8842b9575005190fde2898764628
61 changes: 61 additions & 0 deletions trunk/drivers/staging/lttng/lib/align.h
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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

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