Re: [RFC] add struct hw_interrupt_type->release

[Christoph Hellwig <hch@infradead.org>]

On Wed, Oct 20, 2004 at 07:26:30PM -0700, Chris Wedgwood wrote:
> On Tue, Oct 19, 2004 at 07:31:56PM -0700, Chris Wedgwood wrote:
> 
> > +++ b/kernel/irq/manage.c	2004-10-19 17:47:40 -07:00
> > @@ -260,6 +260,7 @@
> >  				else
> >  					desc->handler->disable(irq);
> >  			}
>                        ^^^
> > +			platform_free_irq_notify(irq, dev_id);
> >  			spin_unlock_irqrestore(&desc->lock,flags);
> >  			unregister_handler_proc(irq, action);
> >  
> 
> On Wed, Oct 20, 2004 at 02:07:15PM +0100, Christoph Hellwig wrote:
> 
> > This looks rather bogus to me.  What prevents UML from doing it's
> > work at the struct hw_interrupt_type level?
> 
> the ^^^ marked part reads something like if (!desc->action) { ... }
> presumably meaning the shutdown/disable is only done when the very
> last user of an interrupt source is removed
> 
> UML needs to be notified when *any* user is removed so either need
> some way to tell the generic code this or perhaps we could introduce
> another op to hw_interrupt_type along the lines of ->release like
> this:

Care to explain why it needs that?  How exactly is UML using hardirqs,
they seems to fit very badly into the concept of a usermode kernel if
you ask me.  Maybe UML would be better off to not use hardirqs at all,
ala s390.