lib: bitmap: remove redundant code from __bitmap_shift_left
The first of these conditionals is completely redundant: If k == lim-1, we
must have off==0, so the second conditional will also trigger and then it
wouldn't matter if upper had some high bits set. But the second
conditional is in fact also redundant, since it only serves to clear out
some high-order "don't care" bits of dst, about which no guarantee is
made.
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 36e380d..a13c7f4 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -159,7 +159,7 @@
unsigned int shift, unsigned int nbits)
{
int k;
- unsigned int lim = BITS_TO_LONGS(nbits), left = nbits % BITS_PER_LONG;
+ unsigned int lim = BITS_TO_LONGS(nbits);
unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
for (k = lim - off - 1; k >= 0; --k) {
unsigned long upper, lower;
@@ -172,13 +172,8 @@
lower = src[k - 1] >> (BITS_PER_LONG - rem);
else
lower = 0;
- upper = src[k];
- if (left && k == lim - 1)
- upper &= (1UL << left) - 1;
- upper <<= rem;
+ upper = src[k] << rem;
dst[k + off] = lower | upper;
- if (left && k + off == lim - 1)
- dst[k + off] &= (1UL << left) - 1;
}
if (off)
memset(dst, 0, off*sizeof(unsigned long));