Message-ID: <437D92C5.1060902@ccoss.com.cn>
Date: Fri, 18 Nov 2005 16:37:25 +0800
From: liyu <liyu@ccoss.com.cn>
Reply-To: liyu@ccoss.com.cn
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CC: LKML <linux-kernel@vger.kernel.org>
Subject: [Question] spin_lock in interrupt handler.
References: <4379B5EB.40709@ccoss.com.cn> <437A8867.8080809@ccoss.com.cn> <437C2133.2030103@ccoss.com.cn> <200511172057.33131.kernel@kolivas.org>
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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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