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>
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 761d2d4..db88512 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -113,9 +113,9 @@
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 @@
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;