[Intel-gfx] [PATCH 2/3] drm/i915/gtt: refactor the storage assumptions around paging structures

[Chris Wilson]

Quoting Matthew Auld (2020-01-03 20:00:29)
> We currently assume we have struct pages for the backing storage of our
> paging structures, however in the future we may also want to support
> allocating storage from non-page backed memory, while still being able
> to map it into the kernel address space for CPU access.

Please, let's not put a vfunc this deep / frequent. The next step was to
move this into gt/intel_gtt.c, gt/gen6_ppgtt.c, gt/gen8_ppgtt.c and
possibly gt/gen12_ppgtt.c for future directions.
-Chris