Blame view

kernel/linux-rt-4.4.41/include/asm-generic/bitops/lock.h 1.19 KB
5113f6f70   김현기   kernel add
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
  #ifndef _ASM_GENERIC_BITOPS_LOCK_H_
  #define _ASM_GENERIC_BITOPS_LOCK_H_
  
  /**
   * 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 operation is atomic and provides acquire barrier semantics.
   * It can be used to implement bit locks.
   */
  #define test_and_set_bit_lock(nr, addr)	test_and_set_bit(nr, addr)
  
  /**
   * clear_bit_unlock - Clear a bit in memory, for unlock
   * @nr: the bit to set
   * @addr: the address to start counting from
   *
   * This operation is atomic and provides release barrier semantics.
   */
  #define clear_bit_unlock(nr, addr)	\
  do {					\
  	smp_mb__before_atomic();	\
  	clear_bit(nr, addr);		\
  } while (0)
  
  /**
   * __clear_bit_unlock - Clear a bit in memory, for unlock
   * @nr: the bit to set
   * @addr: the address to start counting from
   *
   * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
   * the bits in the word are protected by this lock some archs can use weaker
   * ops to safely unlock.
   *
   * See for example x86's implementation.
   */
  #define __clear_bit_unlock(nr, addr)	\
  do {					\
  	smp_mb__before_atomic();	\
  	clear_bit(nr, addr);		\
  } while (0)
  
  #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */