Re: [PATCH] swiotlb: ensure io_tlb_default_mem spinlock always initialised

[Christoph Hellwig]

On Mon, Jul 11, 2022 at 11:07:17AM +0100, Robin Murphy wrote:
> If none of your peripherals should need SWIOTLB, then the fact that
> you're ending up in swiotlb_map() at all is a clear sign that
> something's wrong. Most likely someone's forgotten to set their DMA
> masks correctly.

Yes.

>
> However, by inspection it seems we do have a bug here as well, for which
> the correct fix should be as below. The fireworks you're *supposed* to
> get in that situation are considerably louder and more obvious than a
> DEBUG_SPINLOCK complaint ;)

This looks sensible, I'll pick it up.