[RFC PATCH kernel] powerpc/xive: Drop deregistered irqs

[Benjamin Herrenschmidt]

On Sun, 2019-07-14 at 21:44 +0200, Cédric Le Goater wrote:
> > Well, best is probably to do just that though, but call it something
> > like ppc_md.orphan_irq() or something like that instead. Another option
> > as you mention is to try to scrub queues, but that's trickier to do due
> > to the lockless nature of the queue handling.
> 
> When the IRQ is shutdown, couldn't we cleanup the CPU EQ by filtering 
> all the dangling entries, and replacing them with zeroes ? That would
> be alternative 1, but I don't think we need to scan all cpus. The last
> target should be enough.

It's a bit tricky due to the lockless nature of the queues...

Cheers,
Ben.