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>
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@ -191,7 +191,7 @@ static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
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const unsigned long *src2, unsigned int nbits)
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{
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if (small_const_nbits(nbits))
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return (*dst = *src1 & *src2) != 0;
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return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
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return __bitmap_and(dst, src1, src2, nbits);
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}
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@ -185,11 +185,14 @@ int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, unsigned int bits)
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{
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unsigned int k;
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unsigned int nr = BITS_TO_LONGS(bits);
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unsigned int lim = bits/BITS_PER_LONG;
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unsigned long result = 0;
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for (k = 0; k < nr; k++)
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for (k = 0; k < lim; k++)
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result |= (dst[k] = bitmap1[k] & bitmap2[k]);
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if (bits % BITS_PER_LONG)
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result |= (dst[k] = bitmap1[k] & bitmap2[k] &
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BITMAP_LAST_WORD_MASK(bits));
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return result != 0;
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}
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EXPORT_SYMBOL(__bitmap_and);
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