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

Thomas Gleixner
2010-12-15T08:05:25Z

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.

Thanks,

tglx