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authorRasmus Villemoes <linux@rasmusvillemoes.dk>2014-08-06 16:10:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-06 18:01:27 -0700
commit7e5f97d1927f41affa21aa5b321865ceab1994ce (patch)
tree671aaafdac301ef670434667f4b157cd127d8525
parentc5341ec8904ebff50f365a2626da6ab525d63b9e (diff)
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lib: bitmap: add missing mask in bitmap_and
Apparently, bitmap_and is supposed to return whether the new bitmap is empty. But it didn't take potential garbage bits in the last word into account. 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>
-rw-r--r--include/linux/bitmap.h2
-rw-r--r--lib/bitmap.c7
2 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 75df61d9ecfb..3399a9ecd991 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -191,7 +191,7 @@ static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
if (small_const_nbits(nbits))
- return (*dst = *src1 & *src2) != 0;
+ return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
return __bitmap_and(dst, src1, src2, nbits);
}
diff --git a/lib/bitmap.c b/lib/bitmap.c
index faaf7206d4cf..ce2ec80bf431 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -185,11 +185,14 @@ int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int bits)
{
unsigned int k;
- unsigned int nr = BITS_TO_LONGS(bits);
+ unsigned int lim = bits/BITS_PER_LONG;
unsigned long result = 0;
- for (k = 0; k < nr; k++)
+ for (k = 0; k < lim; k++)
result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+ if (bits % BITS_PER_LONG)
+ result |= (dst[k] = bitmap1[k] & bitmap2[k] &
+ BITMAP_LAST_WORD_MASK(bits));
return result != 0;
}
EXPORT_SYMBOL(__bitmap_and);