From: tip-bot for Paul Walmsley <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org,
torvalds@linux-foundation.org, peterz@infradead.org,
arnd@arndb.de, akpm@linux-foundation.org, tglx@linutronix.de,
pwalmsley@nvidia.com
Subject: [tip:core/types] bitops: Fix signedness of compile-time hweight implementations
Date: Mon, 10 Feb 2014 05:30:28 -0800 [thread overview]
Message-ID: <tip-c32fa99f0b4252633aa464e28d1cb925bd2a79df@git.kernel.org> (raw)
In-Reply-To: <alpine.DEB.2.02.1312180459580.30198@tamien>
Commit-ID: c32fa99f0b4252633aa464e28d1cb925bd2a79df
Gitweb: http://git.kernel.org/tip/c32fa99f0b4252633aa464e28d1cb925bd2a79df
Author: Paul Walmsley <pwalmsley@nvidia.com>
AuthorDate: Wed, 18 Dec 2013 05:02:14 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 9 Feb 2014 13:39:26 +0100
bitops: Fix signedness of compile-time hweight implementations
Enabling '-Wsign-compare' compiler warnings on code that includes
include/linux/bitops.h can generate the following warning:
In file included from include/linux/kernel.h:10:0,
from <random filename>:48:
include/linux/bitops.h: In function 'hweight_long':
include/linux/bitops.h:77:26: error: signed and unsigned type in conditional expression [-Werror=sign-compare]
(converted to an error with -Werror)
This is due to the use of the logical negation operator '!' in the
__const_hweight8 macro in include/asm-generic/bitops/const_hweight.h.
The use of that operator here results in a signed value.
Fix by explicitly casting the __const_hweight8 macro expansion to
'unsigned int'. While here, clean up several checkpatch.pl warnings.
Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1312180459580.30198@tamien
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/asm-generic/bitops/const_hweight.h | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/include/asm-generic/bitops/const_hweight.h b/include/asm-generic/bitops/const_hweight.h
index fa2a50b..0a7e066 100644
--- a/include/asm-generic/bitops/const_hweight.h
+++ b/include/asm-generic/bitops/const_hweight.h
@@ -5,14 +5,15 @@
* Compile time versions of __arch_hweightN()
*/
#define __const_hweight8(w) \
- ( (!!((w) & (1ULL << 0))) + \
- (!!((w) & (1ULL << 1))) + \
- (!!((w) & (1ULL << 2))) + \
- (!!((w) & (1ULL << 3))) + \
- (!!((w) & (1ULL << 4))) + \
- (!!((w) & (1ULL << 5))) + \
- (!!((w) & (1ULL << 6))) + \
- (!!((w) & (1ULL << 7))) )
+ ((unsigned int) \
+ ((!!((w) & (1ULL << 0))) + \
+ (!!((w) & (1ULL << 1))) + \
+ (!!((w) & (1ULL << 2))) + \
+ (!!((w) & (1ULL << 3))) + \
+ (!!((w) & (1ULL << 4))) + \
+ (!!((w) & (1ULL << 5))) + \
+ (!!((w) & (1ULL << 6))) + \
+ (!!((w) & (1ULL << 7)))))
#define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 ))
#define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
prev parent reply other threads:[~2014-02-10 13:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-18 13:02 [PATCH] bitops: fix signedness of compile-time hweight implementations Paul Walmsley
2013-12-18 13:02 ` Paul Walmsley
2014-01-22 17:19 ` Paul Walmsley
2014-01-22 17:47 ` Peter Zijlstra
2014-02-10 13:30 ` tip-bot for Paul Walmsley [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=tip-c32fa99f0b4252633aa464e28d1cb925bd2a79df@git.kernel.org \
--to=tipbot@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=pwalmsley@nvidia.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.