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author | Peter Xu <peterx@redhat.com> | 2018-08-22 15:19:56 +0800 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-08-22 16:48:36 +0200 |
commit | 07a262cc7c586e3f385a61b8870b0913bf31309a (patch) | |
tree | 811be68591ad09d41e9a898c5ae95912d8491392 | |
parent | 024d83cadc6b2af027e473720f3c3da97496c318 (diff) |
tools: introduce test_and_clear_bit
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>
-rw-r--r-- | tools/include/linux/bitmap.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h index 63440cc8d618..e63662db131b 100644 --- a/tools/include/linux/bitmap.h +++ b/tools/include/linux/bitmap.h @@ -97,6 +97,23 @@ static inline int test_and_set_bit(int nr, unsigned long *addr) } /** + * 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 */ |