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tools: introduce test_and_clear_bit

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We have test_and_set_bit but not test_and_clear_bit.  Add it.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Xu
2018-08-22 15:19:56 +08:00
committed by Paolo Bonzini
parent 024d83cadc
commit 07a262cc7c
1 changed files with 17 additions and 0 deletions
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17
tools/include/linux/bitmap.h
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@@ -96,6 +96,23 @@ static inline int test_and_set_bit(int nr, unsigned long *addr)
return (old & mask) != 0; 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 * bitmap_alloc - Allocate bitmap
* @nbits: Number of bits * @nbits: Number of bits