• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 #ifndef _ASM_GENERIC_BITOPS_LOCK_H_
2 #define _ASM_GENERIC_BITOPS_LOCK_H_
3 
4 /**
5  * test_and_set_bit_lock - Set a bit and return its old value, for lock
6  * @nr: Bit to set
7  * @addr: Address to count from
8  *
9  * This operation is atomic and provides acquire barrier semantics.
10  * It can be used to implement bit locks.
11  */
12 #define test_and_set_bit_lock(nr, addr)	test_and_set_bit(nr, addr)
13 
14 /**
15  * clear_bit_unlock - Clear a bit in memory, for unlock
16  * @nr: the bit to set
17  * @addr: the address to start counting from
18  *
19  * This operation is atomic and provides release barrier semantics.
20  */
21 #define clear_bit_unlock(nr, addr)	\
22 do {					\
23 	smp_mb__before_clear_bit();	\
24 	clear_bit(nr, addr);		\
25 } while (0)
26 
27 /**
28  * __clear_bit_unlock - Clear a bit in memory, for unlock
29  * @nr: the bit to set
30  * @addr: the address to start counting from
31  *
32  * This operation is like clear_bit_unlock, however it is not atomic.
33  * It does provide release barrier semantics so it can be used to unlock
34  * a bit lock, however it would only be used if no other CPU can modify
35  * any bits in the memory until the lock is released (a good example is
36  * if the bit lock itself protects access to the other bits in the word).
37  */
38 #define __clear_bit_unlock(nr, addr)	\
39 do {					\
40 	smp_mb();			\
41 	__clear_bit(nr, addr);		\
42 } while (0)
43 
44 #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
45 
46