Commit 2fc016c5bd8a ("linux/const.h: Add _BITUL() and _BITULL()")
introduced _BITUL() and _BITULL(). Its git-log says the difference
from the already existing BIT() are:
1. The namespace is such that they can be used in uapi definitions.
2. The type is set with the _AC() macro to allow it to be used in
assembly.
3. The type is explicitly specified to be UL or ULL.
However, I found _BITUL() is mostly used in kernel-space since it is
handy to share headers between C and assembly. If we only need '2.',
we can improve the existing BIT() for use in assembly, allowing us to
avoid unnecessary underscore prefixes.
Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com>
---
V2: https://patchwork.kernel.org/patch/9498271/
Changes in v3: None
Changes in v2: None
include/linux/bitops.h | 3 +--
include/linux/const.h | 3 +++
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 4cac4e1..8a856be 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -1,11 +1,10 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_BITOPS_H
#define _LINUX_BITOPS_H
+#include <linux/const.h>
#include <asm/types.h>
#ifdef __KERNEL__
-#define BIT(nr) (1UL << (nr))
-#define BIT_ULL(nr) (1ULL << (nr))
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BIT_ULL_MASK(nr) (1ULL << ((nr) % BITS_PER_LONG_LONG))
diff --git a/include/linux/const.h b/include/linux/const.h
index 7b55a55..200892d 100644
--- a/include/linux/const.h
+++ b/include/linux/const.h
@@ -6,4 +6,7 @@
#define UL(x) (_UL(x))
#define ULL(x) (_ULL(x))
+#define BIT(x) (_BITUL(x))
+#define BIT_ULL(x) (_BITULL(x))
+
#endif /* _LINUX_CONST_H */
--
2.7.4
