From 2d31597d37ec8842b9575005190fde2898764628 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 28 Nov 2011 07:42:12 -0500 Subject: [PATCH] lttng: offset alignment header Signed-off-by: Mathieu Desnoyers Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lttng/lib/align.h | 61 +++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 drivers/staging/lttng/lib/align.h diff --git a/drivers/staging/lttng/lib/align.h b/drivers/staging/lttng/lib/align.h new file mode 100644 index 000000000000..0b861000300c --- /dev/null +++ b/drivers/staging/lttng/lib/align.h @@ -0,0 +1,61 @@ +#ifndef _LTTNG_ALIGN_H +#define _LTTNG_ALIGN_H + +/* + * lib/align.h + * + * (C) Copyright 2010-2011 - Mathieu Desnoyers + * + * Dual LGPL v2.1/GPL v2 license. + */ + +#ifdef __KERNEL__ + +#include +#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 -- 2.39.2