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  • Paul Walmsley's avatar
    bitops: Fix signedness of compile-time hweight implementations · c32fa99f
    Paul Walmsley authored
    
    
    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: default avatarPaul 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: default avatarPeter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1312180459580.30198@tamien
    
    
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    c32fa99f