[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / asm-generic / bitops / lock.h

#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_clear_bit();	\
	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
 *
 * This operation is like clear_bit_unlock, however it is not atomic.
 * It does provide release barrier semantics so it can be used to unlock
 * a bit lock, however it would only be used if no other CPU can modify
 * any bits in the memory until the lock is released (a good example is
 * if the bit lock itself protects access to the other bits in the word).
 */
#define __clear_bit_unlock(nr, addr)	\
do {					\
	smp_mb();			\
	__clear_bit(nr, addr);		\
} while (0)

#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
Commit	Line	Data
26333576 NP	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