From 07a262cc7c586e3f385a61b8870b0913bf31309a Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 22 Aug 2018 15:19:56 +0800 Subject: [PATCH] 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 Signed-off-by: Paolo Bonzini --- tools/include/linux/bitmap.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) 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 @@ -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