From 7f590657937f1c59163ff14a13062439a18e4a37 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Fri, 13 Feb 2015 14:36:19 -0800
Subject: [PATCH] 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>
---
lib/bitmap.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 36e380da00c5..a13c7f4e325a 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -159,7 +159,7 @@ void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
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 @@ void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
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));