[PATCH] drm/lease: look at ->universal_planes only once

[Daniel Vetter]

On Mon, Nov 05, 2018 at 11:12:11AM +0100, Daniel Vetter wrote:
> It's lockless, and userspace might chance it underneath us. That's not
> really a problem, all userspace gets is a slightly dysfunctional
> lease with the current code. But this might change, and gcc might
> decide to reload a few too many times, and then boom. So better safe
> than sorry.
> 
> v2: Remove the now unused lessor_priv argument from validate_lease()
> (Keith).
> 
> v3: Actually add everything ... silly me.
> 
> Cc: Keith Packard <keithp at keithp.com>
> Cc: Dave Airlie <airlied at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

All pulled in with CI approving and Keith's irc-ack on this one here.
-Daniel

> ---
>  drivers/gpu/drm/drm_lease.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
> index 3b0342a45ae9..3650d3c46718 100644
> --- a/drivers/gpu/drm/drm_lease.c
> +++ b/drivers/gpu/drm/drm_lease.c
> @@ -353,9 +353,9 @@ void drm_lease_revoke(struct drm_master *top)
>  }
>  
>  static int validate_lease(struct drm_device *dev,
> -			  struct drm_file *lessor_priv,
>  			  int object_count,
> -			  struct drm_mode_object **objects)
> +			  struct drm_mode_object **objects,
> +			  bool universal_planes)
>  {
>  	int o;
>  	int has_crtc = -1;
> @@ -372,14 +372,14 @@ static int validate_lease(struct drm_device *dev,
>  		if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)
>  			has_connector = o;
>  
> -		if (lessor_priv->universal_planes) {
> +		if (universal_planes) {
>  			if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)
>  				has_plane = o;
>  		}
>  	}
>  	if (has_crtc == -1 || has_connector == -1)
>  		return -EINVAL;
> -	if (lessor_priv->universal_planes && has_plane == -1)
> +	if (universal_planes && has_plane == -1)
>  		return -EINVAL;
>  	return 0;
>  }
> @@ -393,6 +393,8 @@ static int fill_object_idr(struct drm_device *dev,
>  	struct drm_mode_object **objects;
>  	u32 o;
>  	int ret;
> +	bool universal_planes = READ_ONCE(lessor_priv->universal_planes);
> +
>  	objects = kcalloc(object_count, sizeof(struct drm_mode_object *),
>  			  GFP_KERNEL);
>  	if (!objects)
> @@ -421,7 +423,7 @@ static int fill_object_idr(struct drm_device *dev,
>  		}
>  	}
>  
> -	ret = validate_lease(dev, lessor_priv, object_count, objects);
> +	ret = validate_lease(dev, object_count, objects, universal_planes);
>  	if (ret) {
>  		DRM_DEBUG_LEASE("lease validation failed\n");
>  		goto out_free_objects;
> @@ -448,7 +450,7 @@ static int fill_object_idr(struct drm_device *dev,
>  					object_id, ret);
>  			goto out_free_objects;
>  		}
> -		if (obj->type == DRM_MODE_OBJECT_CRTC && !lessor_priv->universal_planes) {
> +		if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
>  			struct drm_crtc *crtc = obj_to_crtc(obj);
>  			ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);
>  			if (ret < 0) {
> -- 
> 2.14.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch