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From: Rolf Eike Beer <eike-kernel@sf-tec.de>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	stable@kernel.org
Subject: [PATCH] Fix roundup_pow_of_two(1)
Date: Thu, 17 May 2007 23:56:56 +0200	[thread overview]
Message-ID: <200705172356.57620.eike-kernel@sf-tec.de> (raw)

Fix roundup_pow_of_two(1)

1 is a power of two, therefore roundup_pow_of_two(1) should return 1. It does
in case the argument is a variable but in case it's a constant it behaves
wrong and returns 0. Probably nobody ever did it so this was never noticed.

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>

---
commit 01ceeffac83011f0b5021013cc4abd1c4f291df5
tree 7da59df51617d7cebd55e4361019181645a17e10
parent ab35916f807eb4f2019a208e96cb0bddbb91dfc3
author Rolf Eike Beer <eike-kernel@sf-tec.de> Thu, 17 May 2007 23:43:54 +0200
committer Rolf Eike Beer <eike-kernel@sf-tec.de> Thu, 17 May 2007 23:43:54 +0200

 include/linux/log2.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/log2.h b/include/linux/log2.h
index 57e641e..1b8a2c1 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -159,7 +159,7 @@ unsigned long __roundup_pow_of_two(unsigned long n)
 #define roundup_pow_of_two(n)			\
 (						\
 	__builtin_constant_p(n) ? (		\
-		(n == 1) ? 0 :			\
+		(n == 1) ? 1 :			\
 		(1UL << (ilog2((n) - 1) + 1))	\
 				   ) :		\
 	__roundup_pow_of_two(n)			\

             reply	other threads:[~2007-05-18  8:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-17 21:56 Rolf Eike Beer [this message]
2007-06-04 11:49 ` [PATCH] Fix roundup_pow_of_two(1) Adrian Bunk
2007-06-04 12:13   ` Rolf Eike Beer
2007-06-04 13:17     ` Adrian Bunk
2007-06-04 12:33   ` Jiri Kosina

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