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Nick Piggin26333572007-10-18 03:06:39 -07001#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) \
22do { \
Peter Zijlstra4e857c52014-03-17 18:06:10 +010023 smp_mb__before_atomic(); \
Nick Piggin26333572007-10-18 03:06:39 -070024 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) \
39do { \
40 smp_mb(); \
41 __clear_bit(nr, addr); \
42} while (0)
43
44#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
45