Re: [PATCH 07/11] drm/i915: stop using kmap in i915_gem_object_map

[Tvrtko Ursulin]

On 24/09/2020 14:58, Christoph Hellwig wrote:
> kmap for !PageHighmem is just a convoluted way to say page_address,
> and kunmap is a no-op in that case.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_pages.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> index d6eeefab3d018b..6550c0bc824ea2 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> @@ -162,8 +162,6 @@ static void unmap_object(struct drm_i915_gem_object *obj, void *ptr)
>   {
>   	if (is_vmalloc_addr(ptr))
>   		vunmap(ptr);
> -	else
> -		kunmap(kmap_to_page(ptr));
>   }
>   
>   struct sg_table *
> @@ -277,11 +275,10 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
>   		 * forever.
>   		 *
>   		 * So if the page is beyond the 32b boundary, make an explicit
> -		 * vmap. On 64b, this check will be optimised away as we can
> -		 * directly kmap any page on the system.
> +		 * vmap.
>   		 */
>   		if (!PageHighMem(page))
> -			return kmap(page);
> +			return page_address(page);
>   	}
>   
>   	mem = stack;

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>

Regards,

Tvrtko