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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_GENERIC_BITOPS_LOCK_H_
3#define _ASM_GENERIC_BITOPS_LOCK_H_
4
5/**
6 * test_and_set_bit_lock - Set a bit and return its old value, for lock
7 * @nr: Bit to set
8 * @addr: Address to count from
9 *
10 * This operation is atomic and provides acquire barrier semantics if
11 * the returned value is 0.
12 * It can be used to implement bit locks.
13 */
14#define test_and_set_bit_lock(nr, addr) test_and_set_bit(nr, addr)
15
16/**
17 * clear_bit_unlock - Clear a bit in memory, for unlock
18 * @nr: the bit to set
19 * @addr: the address to start counting from
20 *
21 * This operation is atomic and provides release barrier semantics.
22 */
23#define clear_bit_unlock(nr, addr) \
24do { \
25 smp_mb__before_atomic(); \
26 clear_bit(nr, addr); \
27} while (0)
28
29/**
30 * __clear_bit_unlock - Clear a bit in memory, for unlock
31 * @nr: the bit to set
32 * @addr: the address to start counting from
33 *
34 * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
35 * the bits in the word are protected by this lock some archs can use weaker
36 * ops to safely unlock.
37 *
38 * See for example x86's implementation.
39 */
40#define __clear_bit_unlock(nr, addr) \
41do { \
42 smp_mb__before_atomic(); \
43 clear_bit(nr, addr); \
44} while (0)
45
46#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
47