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Make bitmask 'and' operators return a result code

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When 'and'ing two bitmasks (where 'andnot' is a variation on it), some
cases want to know whether the result is the empty set or not.  In
particular, the TLB IPI sending code wants to do cpumask operations and
determine if there are any CPU's left in the final set.

So this just makes the bitmask (and cpumask) functions return a boolean
for whether the result has any bits set.

Cc: stable@kernel.org (2.6.30, needed by TLB shootdown fix)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
2009-08-21 09:26:15 -07:00
parent 83d349f35e
commit f4b0373b26
3 changed files with 26 additions and 24 deletions
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12
lib/bitmap.c
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@@ -179,14 +179,16 @@ void __bitmap_shift_left(unsigned long *dst,
}
EXPORT_SYMBOL(__bitmap_shift_left);
void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
unsigned long result = 0;
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & bitmap2[k];
result |= (dst[k] = bitmap1[k] & bitmap2[k]);
return result != 0;
}
EXPORT_SYMBOL(__bitmap_and);
@@ -212,14 +214,16 @@ void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
}
EXPORT_SYMBOL(__bitmap_xor);
void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
unsigned long result = 0;
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & ~bitmap2[k];
result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
return result != 0;
}
EXPORT_SYMBOL(__bitmap_andnot);