Commit-ID: c32fa99f0b4252633aa464e28d1cb925bd2a79df
Gitweb: http://git.kernel.org/tip/c32fa99f0b4252633aa464e28d1cb925bd2a79df
Author: Paul Walmsley <[email protected]>
AuthorDate: Wed, 18 Dec 2013 05:02:14 -0800
Committer: Ingo Molnar <[email protected]>
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 <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1312180459580.30198@tamien
Signed-off-by: Ingo Molnar <[email protected]>
---
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))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
