diff options
Diffstat (limited to 'include/asm-x86/bitops_64.h')
| -rw-r--r-- | include/asm-x86/bitops_64.h | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/include/asm-x86/bitops_64.h b/include/asm-x86/bitops_64.h index dacaa5f..b4d4794 100644 --- a/include/asm-x86/bitops_64.h +++ b/include/asm-x86/bitops_64.h @@ -72,6 +72,20 @@ static __inline__ void clear_bit(int nr, volatile void * addr) :"dIr" (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 void * addr) { __asm__ __volatile__( @@ -80,6 +94,24 @@ static __inline__ void __clear_bit(int nr, volatile void * addr) :"dIr" (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() @@ -137,6 +169,15 @@ static __inline__ int test_and_set_bit(int nr, volatile void * 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 + */ +#define test_and_set_bit_lock test_and_set_bit + +/** * __test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from @@ -412,7 +453,6 @@ static __inline__ int fls(int x) #define ARCH_HAS_FAST_MULTIPLIER 1 #include <asm-generic/bitops/hweight.h> -#include <asm-generic/bitops/lock.h> #endif /* __KERNEL__ */ |