[Question] spin_lock in interrupt handler.

From: liyu
Date: Fri Nov 18 2005 - 03:36:57 EST

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.


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