lkml.org 
[lkml]   [2009]   [Aug]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC patch 2/3] genirq: Add buslock support for irq chips on slow busses
On Fri, 14 Aug 2009, Peter Zijlstra wrote:
> On Thu, 2009-08-13 at 19:40 +0000, Thomas Gleixner wrote:
> >
> > +/**
> > + * disable_slowbus_irq - disable an slowbus irq and wait for completion
> > + * @irq: Interrupt to disable
> > + *
> > + * Disable the selected interrupt line. Enables and Disables are
> > + * nested.
> > + * This function waits for any pending IRQ handlers for this interrupt
> > + * to complete before returning. If you use this function while
> > + * holding a resource the IRQ handler may need you will deadlock.
> > + *
> > + * This function must not be called from IRQ context.
> > + */
> > +void disable_slowbus_irq(unsigned int irq)
> > +{
> > + struct irq_desc *desc = irq_to_desc(irq);
> > +
> > + if (!desc || !desc->chip || !desc->chip->bus_lock)
> > + return;
> > +
> > + desc->chip->bus_lock(irq);
> > + disable_irq_nosync(irq);
> > + if (desc->action)
> > + synchronize_irq(irq);
> > + desc->chip->bus_sync_unlock(irq);
> > +}
> > +EXPORT_SYMBOL(disable_slowbus_irq);
>
> Should we also not check that desc->chip->bus_lock is not set for the
> regular function disable_irq()?
>
> It seems to me mixing disable_irq() and disable_slowbus_irq() is a
> recipe for disaster.
>
> Same for the other slowbus functions of course.

Yeah, that's what I wanted to avoid with the first version, which did
the conditional locking and did not require a separate API, but Ingo
frowned upon the conditional lock.

Thanks,

tglx



\
 
 \ /
  Last update: 2009-08-14 11:07    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site