Re: [PATCH v7 07/15] swiotlb: Update is_swiotlb_active to add a struct device argument

[Christoph Hellwig]

> +	if (is_swiotlb_active(NULL)) {

Passing a NULL argument to this doesn't make sense.  They all should have
a struct device at hand, you'll just need to dig for it.

And this function should be about to go away anyway, but until then we
need to do this properly.