--- zzzz-none-000/linux-3.10.107/include/asm-generic/bitops/lock.h 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/include/asm-generic/bitops/lock.h 2021-02-04 17:41:59.000000000 +0000 @@ -20,7 +20,7 @@ */ #define clear_bit_unlock(nr, addr) \ do { \ - smp_mb__before_clear_bit(); \ + smp_mb__before_atomic(); \ clear_bit(nr, addr); \ } while (0) @@ -29,16 +29,16 @@ * @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). + * 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(); \ - __clear_bit(nr, addr); \ + smp_mb__before_atomic(); \ + clear_bit(nr, addr); \ } while (0) #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */