mirror of https://gitee.com/openkylin/linux.git
46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
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#ifndef _ASM_GENERIC_BITOPS_LOCK_H_
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#define _ASM_GENERIC_BITOPS_LOCK_H_
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/**
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* test_and_set_bit_lock - Set a bit and return its old value, for lock
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is atomic and provides acquire barrier semantics.
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* It can be used to implement bit locks.
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*/
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#define test_and_set_bit_lock(nr, addr) test_and_set_bit(nr, addr)
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/**
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* clear_bit_unlock - Clear a bit in memory, for unlock
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* This operation is atomic and provides release barrier semantics.
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*/
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#define clear_bit_unlock(nr, addr) \
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do { \
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smp_mb__before_clear_bit(); \
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clear_bit(nr, addr); \
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} while (0)
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/**
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* __clear_bit_unlock - Clear a bit in memory, for unlock
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* This operation is like clear_bit_unlock, however it is not atomic.
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* It does provide release barrier semantics so it can be used to unlock
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* a bit lock, however it would only be used if no other CPU can modify
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* any bits in the memory until the lock is released (a good example is
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* if the bit lock itself protects access to the other bits in the word).
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*/
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#define __clear_bit_unlock(nr, addr) \
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do { \
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smp_mb(); \
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__clear_bit(nr, addr); \
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} while (0)
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#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
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