[Question] spin_lock in interrupt handler.

[liyu <liyu@ccoss.com.cn>]

Hi, every one in LKML.

   I have one question about how to use spin_lock.

   I read Documentation/spinlocks.txt wrote by Linus. The Lesson 1 and 
2 are simple for me.
But I confused in Lesson 3. The most doublt is why we can not use 
spin_lock_irq*() version in
interrupt handler?

   At i386, I known the interrupt is disabled in interrupt handler. I 
think this feature is
supplied in handware-level. The spin_lock_irqrestore() will use  'sti'  
instruction internal, it will change interrupt mask bit in FLAGS 
register, do this have re-enable interrupt, even in interrput handler? I 
can not sure this.

   Thanks in advanced.

-liyu
  


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