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SubjectRe: [patch 3/3] genirq: introduce IRQF_ALLOW_NESTED flag for request_irq()
On Tue, 16 Mar 2010 09:36:59 +0100
Marc Zyngier <maz@misterjones.org> wrote:

> On Sat, 13 Mar 2010 20:56:19 +0100 (CET), Thomas Gleixner
> <tglx@linutronix.de> wrote:
>
> Hi Thomas,
>
> > In general I have no objections, but one thing bothers me. We have no
> > way to let a driver know whether it runs in a nested threaded context
> > or in hard irq context. There might be (future) drivers which would be
> > happy to know that to apply context dependent optimizations etc.
> >
> > What about a new function which solves your problem and returns that
> > information ? Something along the line:
> >
> > int request_any_context_irq(....)
> > {
> > ...
> > if (desc->status & IRQ_NESTED_THREAD) {
> > ret = request_threaded_irq();
> > if (!ret)
> > ret = IRQ_IS_NESTED;
> >
> > } else {
> > .....
> > ret = IRQ_IS_NONTHREADED;
> > else
> > ret = IRQ_IS_THREADED;
> >
> > }
> > ...
> > return ret;
> > }
> >
> > You get the idea, right ?
> >
> > It's a bit more code, but less magic and more flexible for further use
> > cases.
>
> What about the attached (sorry, webmail crap) patch? I deliberately left
> IS_THREADED out of the picture, as I have the feeling that the caller has
> to know if it really wants a threaded handler, and I couldn't see a way to
> guess its intent.
>
> Please note that this patch has only been compile-tested, as I'm traveling
> for the rest of the week and don't have access to my boards.
>
> Thanks,
>
> M.

Any comment on this?

Thanks,

M.
--
I'm the slime oozin' out from your TV set...


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