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) \ 22do { \ 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) \ 39do { \ 40 smp_mb(); \ 41 __clear_bit(nr, addr); \ 42} while (0) 43 44#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */ 45 46