word-at-a-time: simplify big-endian zero_bytemask macro

This is simpler and cleaner.  Depending on architecture, a smart
compiler may or may not generate the same code.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 789ce9dca8007ab5d7c72b9a174a29243817ac32)
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --git a/include/asm-generic/word-at-a-time.h b/include/asm-generic/word-at-a-time.h
index d96deb443f18403d50e813f7a82a478e92a6d064..94f9ea8abcae35af8ca36560403fbd25facb7c65 100644 (file)
--- a/include/asm-generic/word-at-a-time.h
+++ b/include/asm-generic/word-at-a-time.h
@@ -50,7 +50,7 @@ static inline bool has_zero(unsigned long val, unsigned long *data, const struct
 }
 
 #ifndef zero_bytemask
-#define zero_bytemask(mask) (~0ul << __fls(mask) << 1)
+#define zero_bytemask(mask) (~1ul << __fls(mask))
 #endif
 
 #endif /* _ASM_WORD_AT_A_TIME_H */