diff options
Diffstat (limited to 'include/asm-x86/bitops_32.h')
-rw-r--r-- | include/asm-x86/bitops_32.h | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/include/asm-x86/bitops_32.h b/include/asm-x86/bitops_32.h index 3268a341cf49..0b40f6d20bea 100644 --- a/include/asm-x86/bitops_32.h +++ b/include/asm-x86/bitops_32.h @@ -80,6 +80,20 @@ static inline void clear_bit(int nr, volatile unsigned long * addr) :"Ir" (nr)); } +/* + * clear_bit_unlock - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * clear_bit() is atomic and implies release semantics before the memory + * operation. It can be used for an unlock. + */ +static inline void clear_bit_unlock(unsigned long nr, volatile unsigned long *addr) +{ + barrier(); + clear_bit(nr, addr); +} + static inline void __clear_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( @@ -87,6 +101,25 @@ static inline void __clear_bit(int nr, volatile unsigned long * addr) :"+m" (ADDR) :"Ir" (nr)); } + +/* + * __clear_bit_unlock - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * __clear_bit() is non-atomic and implies release semantics before the memory + * operation. It can be used for an unlock if no other CPUs can concurrently + * modify other bits in the word. + * + * No memory barrier is required here, because x86 cannot reorder stores past + * older loads. Same principle as spin_unlock. + */ +static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr) +{ + barrier(); + __clear_bit(nr, addr); +} + #define smp_mb__before_clear_bit() barrier() #define smp_mb__after_clear_bit() barrier() @@ -146,6 +179,18 @@ static inline int test_and_set_bit(int nr, volatile unsigned long * addr) } /** + * test_and_set_bit_lock - Set a bit and return its old value for lock + * @nr: Bit to set + * @addr: Address to count from + * + * This is the same as test_and_set_bit on x86. + */ +static inline int test_and_set_bit_lock(int nr, volatile unsigned long *addr) +{ + return test_and_set_bit(nr, addr); +} + +/** * __test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from @@ -406,7 +451,6 @@ static inline int fls(int x) } #include <asm-generic/bitops/hweight.h> -#include <asm-generic/bitops/lock.h> #endif /* __KERNEL__ */ |