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lib: bitmap: add missing mask in bitmap_andnot 

Apparently, bitmap_andnot 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>
This commit is contained in:
Rasmus Villemoes 2014-08-06 16:10:24 -07:00 committed by Linus Torvalds
parent 7e5f97d192
commit 74e7653190
2 changed files with 6 additions and 3 deletions
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2
include/linux/bitmap.h
View File

@ -217,7 +217,7 @@ static inline int bitmap_andnot(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_andnot(dst, src1, src2, nbits);
}

7
lib/bitmap.c
View File

@ -223,11 +223,14 @@ int __bitmap_andnot(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_andnot);