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Subject: Re: Various bug fixes and improvements - where to put?
From: Linus Nielsen Feltzing (linus_at_haxx.se)
Date: 2004-03-02


[IDC]Dragon wrote:
>>I don't understand what the intention in replacing cli() / sti()
>>by set_irq_level() really is. The comment says that cli() / sti()
>>are not safe.
>
>
> I didn't understand this either, and it seems I have not yet compiled this
> into the version I'm running, else I may have noticed the drag.
> They should be inline functions.

Yes, they should be inline.

The reason that cli()/sti() was unsafe is because they disregarded the
current interrupt level. The sti() function always set the interrupt
level to 0, which is a disaster if called from an interrupt, or when the
interrupt is already disabled, like when you nest the calls.

Linus

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