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Commit 07a262cc authored by Peter Xu's avatar Peter Xu Committed by Paolo Bonzini
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tools: introduce test_and_clear_bit



We have test_and_set_bit but not test_and_clear_bit.  Add it.

Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 024d83ca
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+17 −0
Original line number Diff line number Diff line
@@ -96,6 +96,23 @@ static inline int test_and_set_bit(int nr, unsigned long *addr)
	return (old & mask) != 0;
}

/**
 * test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 */
static inline int test_and_clear_bit(int nr, unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
	unsigned long old;

	old = *p;
	*p = old & ~mask;

	return (old & mask) != 0;
}

/**
 * bitmap_alloc - Allocate bitmap
 * @nbits: Number of bits