Re: Get rid of IRQF_DISABLED - (was [PATCH] genirq: warn aboutIRQF_SHARED|IRQF_DISABLED)

From: Thomas Gleixner
Date: Mon Nov 30 2009 - 09:26:28 EST


On Mon, 30 Nov 2009, Peter Zijlstra wrote:
> On Mon, 2009-11-30 at 14:54 +0100, Thomas Gleixner wrote:
> > The correct solution IMNSHO is to get rid of IRQF_DISABLED and run
> > interrupt handlers always with interrupts disabled and require them
> > not to reenable interrupts themself.
> >
> > Thoughts ?
>
> I'm all for removing that brain damage:
>
> http://lkml.org/lkml/2009/3/2/33

Darn, I knew that we discussed that before, but my memory tricked me
into believing that it was years ago :)

> We should convert the broken hardware PIO and 3com interrupt things to
> threaded interrupts, and simply mandate all IRQ handlers run short and
> with IRQs disabled.

The ide stuff seems to be the only one which uses
local_irq_enable_in_hardirq() so that at least it tripped over lockdep
already.

What's the 3com wreckage about ?

> Except I guess that will upset some of the IRQ priority folks, like
> power, where they (iirc) have a stack per irq prio level.

Is that actually used ? Ben ?

> But its not like the core kernel knows about these nesting rules and can
> actually track any of that muck.

True.

tglx

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