调用spin_lock_irqsave(&chip>lock,flags); 的下层实现是什么？

调用spin_lock_irqsave(&chip->lock,flags); 的下层实现是什么？

#define spin_lock_irqsave(lock, flags) \

do { \

typecheck(unsigned long, flags); \

flags = _spin_lock_irqsave(lock); \

} while (0)
 

 

/*

* Check at compile time that something is of a particular type.

* Always evaluates to 1 so you may use it easily in comparisons.

*/

#define typecheck(type,x) \

({ type __dummy; \

typeof(x) __dummy2; \

(void)(&__dummy == &__dummy2); \

1; \

})

 

#define _spin_lock_irqsave(lock) __spin_lock_irqsave(lock)


static inline unsigned long __spin_lock_irqsave(spinlock_t *lock)

{

unsigned long flags;

local_irq_save(flags);

preempt_disable();

spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);

/*

* On lockdep we dont want the hand-coded irq-enable of

* _raw_spin_lock_flags() code, because lockdep assumes

* that interrupts are not re-enabled during lock-acquire:

*/

#ifdef CONFIG_LOCKDEP

LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);

#else

_raw_spin_lock_flags(lock, &flags);

#endif

return flags;

}
 

为了避免卷入过多的宏定义当中，展开级别暂时停留于此，后面我们将进行最终的展开，展开定义如下所示：

do { ( { unsigned long __dummy ;

typeof ( flags ) __dummy2 ;

( void ) ( & __dummy == & __dummy2 ) ; 1 ; } ) ;

flags = __spin_lock_irqsave ( & chip -> lock ) ;

} while ( 0 )