[Intel-gfx] [PATCH v2 2/2] drm/i915/userptr: fix size calculation

[Chris Wilson]

Quoting Matthew Auld (2020-01-16 20:31:50)
> If we create a rather large userptr object(e.g 1ULL << 32) we might
> shift past the type-width of num_pages: (int)num_pages << PAGE_SHIFT,
> resulting in a totally bogus sg_table, which fortunately will eventually
> manifest as:
> 
> gen8_ppgtt_insert_huge:463 GEM_BUG_ON(iter->sg->length < page_size)
> kernel BUG at drivers/gpu/drm/i915/gt/gen8_ppgtt.c:463!
> 
> v2: more unsigned long
>     prefer I915_GTT_PAGE_SIZE
> 
> Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl")
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

Split into 2 and
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris