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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2015-02-13 14:36:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-13 21:21:35 -0800 |
| commit | cfac1d080a00544e5cecd2d7c9ebe3d6a5cc18e6 (patch) | |
| tree | 8f5d99e331fbd14fedaff8b58625ee4fd5e8190a /lib | |
| parent | 97fb8e940bc56b157517c812c9c6cbfc83d48d78 (diff) | |
| download | lwn-cfac1d080a00544e5cecd2d7c9ebe3d6a5cc18e6.tar.gz lwn-cfac1d080a00544e5cecd2d7c9ebe3d6a5cc18e6.zip | |
lib: bitmap: yet another simplification in __bitmap_shift_right
If left is 0, we can just let mask be ~0UL, so that anding with it is a
no-op. Conveniently, BITMAP_LAST_WORD_MASK provides precisely what we
need, and we can eliminate left.
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 'lib')
| -rw-r--r-- | lib/bitmap.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 761d2d4989ee..db88512c3451 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -113,9 +113,9 @@ EXPORT_SYMBOL(__bitmap_complement); void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, unsigned shift, unsigned nbits) { - unsigned k, lim = BITS_TO_LONGS(nbits), left = nbits % BITS_PER_LONG; + unsigned k, lim = BITS_TO_LONGS(nbits); unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; - unsigned long mask = (1UL << left) - 1; + unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); for (k = 0; off + k < lim; ++k) { unsigned long upper, lower; @@ -127,12 +127,12 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, upper = 0; else { upper = src[off + k + 1]; - if (off + k + 1 == lim - 1 && left) + if (off + k + 1 == lim - 1) upper &= mask; upper <<= (BITS_PER_LONG - rem); } lower = src[off + k]; - if (left && off + k == lim - 1) + if (off + k == lim - 1) lower &= mask; lower >>= rem; dst[k] = lower | upper; |