include/asm-generic/bitops/lock.h

   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.
  11  * It can be used to implement bit locks.
  12  */
  13 #define test_and_set_bit_lock(nr, addr) test_and_set_bit(nr, addr)
  14
  15 /**
  16  * clear_bit_unlock - Clear a bit in memory, for unlock
  17  * @nr: the bit to set
  18  * @addr: the address to start counting from
  19  *
  20  * This operation is atomic and provides release barrier semantics.
  21  */
  22 #define clear_bit_unlock(nr, addr)      \
  23 do {                                    \
  24         smp_mb__before_atomic();        \
  25         clear_bit(nr, addr);            \
  26 } while (0)
  27
  28 /**
  29  * __clear_bit_unlock - Clear a bit in memory, for unlock
  30  * @nr: the bit to set
  31  * @addr: the address to start counting from
  32  *
  33  * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
  34  * the bits in the word are protected by this lock some archs can use weaker
  35  * ops to safely unlock.
  36  *
  37  * See for example x86's implementation.
  38  */
  39 #define __clear_bit_unlock(nr, addr)    \
  40 do {                                    \
  41         smp_mb__before_atomic();        \
  42         clear_bit(nr, addr);            \
  43 } while (0)
  44
  45 #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
  46