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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2015-02-13 14:36:13 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-13 21:21:35 -0800 |
| commit | dba94c2553da1928303c2a6c6410247c88cafc1d (patch) | |
| tree | f6721644e3f883db6d2edccffad73756941b8c00 /include/linux/bitmap.h | |
| parent | cfac1d080a00544e5cecd2d7c9ebe3d6a5cc18e6 (diff) | |
| download | lwn-dba94c2553da1928303c2a6c6410247c88cafc1d.tar.gz lwn-dba94c2553da1928303c2a6c6410247c88cafc1d.zip | |
lib: bitmap: change bitmap_shift_left to take unsigned parameters
gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative. Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.
If off >= lim (which requires shift >= nbits), k is initialized with a
large positive value, but since I've let k continue to be signed, the loop
will never run and dst will be zeroed as expected. Inside the loop, k is
guaranteed to be non-negative, so the fact that it is promoted to unsigned
in the various expressions it appears in is harmless.
Also use "shift" and "nbits" consistently for the parameter names.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/bitmap.h')
| -rw-r--r-- | include/linux/bitmap.h | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index c168a807ab9a..5e7f75a6d7d0 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -98,8 +98,8 @@ extern void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int nbits); extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, unsigned int shift, unsigned int nbits); -extern void __bitmap_shift_left(unsigned long *dst, - const unsigned long *src, int shift, int bits); +extern void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, + unsigned int shift, unsigned int nbits); extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int nbits); extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, @@ -322,13 +322,13 @@ static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *s __bitmap_shift_right(dst, src, shift, nbits); } -static inline void bitmap_shift_left(unsigned long *dst, - const unsigned long *src, int n, int nbits) +static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src, + unsigned int shift, unsigned int nbits) { if (small_const_nbits(nbits)) - *dst = (*src << n) & BITMAP_LAST_WORD_MASK(nbits); + *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); else - __bitmap_shift_left(dst, src, n, nbits); + __bitmap_shift_left(dst, src, shift, nbits); } static inline int bitmap_parse(const char *buf, unsigned int buflen, |