[Intel-gfx] [PATCH 8/8] drm: Remove redundant NULL check during atomic plane commit

[Ville Syrjälä]

On Wed, Apr 26, 2017 at 04:40:13PM +0300, Imre Deak wrote:
> plane_state can't be NULL anywhere in this function, so the NULL check
> at the end is redundant, remove it.
> 
> Cc: dri-devel at lists.freedesktop.org
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/drm_plane_helper.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
> index 9854a50..2c27f6f 100644
> --- a/drivers/gpu/drm/drm_plane_helper.c
> +++ b/drivers/gpu/drm/drm_plane_helper.c
> @@ -511,12 +511,10 @@ int drm_plane_helper_commit(struct drm_plane *plane,
>  	if (plane_funcs->cleanup_fb)
>  		plane_funcs->cleanup_fb(plane, plane_state);
>  out:
> -	if (plane_state) {
> -		if (plane->funcs->atomic_destroy_state)
> -			plane->funcs->atomic_destroy_state(plane, plane_state);
> -		else
> -			drm_atomic_helper_plane_destroy_state(plane, plane_state);
> -	}
> +	if (plane->funcs->atomic_destroy_state)
> +		plane->funcs->atomic_destroy_state(plane, plane_state);
> +	else
> +		drm_atomic_helper_plane_destroy_state(plane, plane_state);

Hmm. If plane->state was NULL, then we could swap that with plane_state,
and thus plane_state could become NULL. But that would actually oops in
drm_atomic_plane_disabling() already, so yeah, no way this could work.

My only concern is the buggy drm_atomic_helper_plane_reset() which can't
fail gracefully if the kmalloc fails. But failure that would probably
lead to explosions all over anyway.

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>


>  
>  	return ret;
>  }
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC