Re: [PATCH v2 4/6] kvm: Extend irqfd to support level interrupts

[Gleb Natapov <gleb@redhat.com>]

On Thu, Jun 28, 2012 at 01:31:29AM +0300, Michael S. Tsirkin wrote:
> On Wed, Jun 27, 2012 at 04:04:18PM -0600, Alex Williamson wrote:
> > On Wed, 2012-06-27 at 18:26 +0300, Michael S. Tsirkin wrote:
> > > On Tue, Jun 26, 2012 at 11:09:46PM -0600, Alex Williamson wrote:
> > > > @@ -71,6 +130,14 @@ irqfd_inject(struct work_struct *work)
> > > >  	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
> > > >  }
> > > >  
> > > > +static void
> > > > +irqfd_inject_level(struct work_struct *work)
> > > > +{
> > > > +	struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
> > > > +
> > > > +	kvm_set_irq(irqfd->kvm, irqfd->source->id, irqfd->gsi, 1);
> > > > +}
> > > > +
> > > >  /*
> > > >   * Race-free decouple logic (ordering is critical)
> > > >   */
> > > 
> > > 
> > > Why is it safe to ignore return value here?
> > > needs a comment.
> > 
> > Well, it seems like you and Gleb came to the conclusion that it's safe,
> > but I can really follow from the list thread.  Can you explain and I'll
> > add a comment?  Thanks,
> > 
> > Alex
> 
> We merely talked about edge interrupts.
> 
In fact it would have been nice to return -EBUSY when write() to level
irqfd is coalesced.

--
			Gleb.