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Commit 7e5f97d1 authored by Rasmus Villemoes's avatar Rasmus Villemoes Committed by Linus Torvalds
Browse files

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: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c5341ec8

include/linux/bitmap.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

lib/bitmap.c

+5 −2
Original line number Diff line number Diff line
@@ -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);