Re: [PATCH v3 2/4] genirq: Inform handler about line sharing state

Thomas Gleixner
2010-12-15T09:48:57Z

On Wed, 15 Dec 2010, Jan Kiszka wrote:
> Am 15.12.2010 09:05, Thomas Gleixner wrote:
> > On Wed, 15 Dec 2010, Jan Kiszka wrote:
> >
> >> Am 14.12.2010 22:46, Thomas Gleixner wrote:
> >>> On Mon, 13 Dec 2010, Jan Kiszka wrote:
> >>>> From: Jan Kiszka <jan.kiszka@siemens.com>
> >>>> chip_bus_lock(desc);
> >>>> retval = __setup_irq(irq, desc, action);
> >>>> chip_bus_sync_unlock(desc);
> >>>>
> >>>> - if (retval)
> >>>> + if (retval) {
> >>>> + if (desc->action && !desc->action->next)
> >>>> + desc->irq_data.drv_status &= ~IRQS_SHARED;
> >>>
> >>> This is redundant. IRQS_SHARED gets set in a code path where all
> >>> checks are done already.
> >>
> >> Nope, it's also set before entry of __setup_irq in case we call an
> >> IRQF_ADAPTIVE handler.
> >>
> >> We need to set it that early as we may race with IRQ events for the
> >> already registered handler happening between the sharing notification
> >> and the actual registration of the second handler.
> >
> > Hmm, ok. Though the MAKE_SHAREABLE flag should be sufficient to do the
> > notification.
>
> For notification, yes. But we need SHARED once we reenable the line
> after the notification.

Darn. Will think more about it.