Re: [PATCH v2 2/2] drm/crtc: only store the necessary data for set_config rollback

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jun 02, 2016 at 07:27:52PM +0200, Philipp Zabel wrote:
> drm_crtc_helper_set_config only potentially touches connector->encoder
> and encoder->crtc, so we only have to store those for all connectors
> and encoders, respectively.
> 
> Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_crtc_helper.c | 36 ++++++++++++++++++------------------
>  1 file changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
> index 1c4d674..26feb2f 100644
> --- a/drivers/gpu/drm/drm_crtc_helper.c
> +++ b/drivers/gpu/drm/drm_crtc_helper.c
> @@ -528,11 +528,11 @@ drm_crtc_helper_disable(struct drm_crtc *crtc)
>  int drm_crtc_helper_set_config(struct drm_mode_set *set)
>  {
>  	struct drm_device *dev;
> -	struct drm_crtc *new_crtc;
> -	struct drm_encoder *save_encoders, *new_encoder, *encoder;
> +	struct drm_crtc **save_encoder_crtcs, *new_crtc;
> +	struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
>  	bool mode_changed = false; /* if true do a full mode set */
>  	bool fb_changed = false; /* if true and !mode_changed just do a flip */
> -	struct drm_connector *save_connectors, *connector;
> +	struct drm_connector *connector;
>  	int count = 0, ro, fail = 0;
>  	const struct drm_crtc_helper_funcs *crtc_funcs;
>  	struct drm_mode_set save_set;
> @@ -574,15 +574,15 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
>  	 * Allocate space for the backup of all (non-pointer) encoder and
>  	 * connector data.
>  	 */
> -	save_encoders = kzalloc(dev->mode_config.num_encoder *
> -				sizeof(struct drm_encoder), GFP_KERNEL);
> -	if (!save_encoders)
> +	save_encoder_crtcs = kzalloc(dev->mode_config.num_encoder *
> +				sizeof(struct drm_crtc *), GFP_KERNEL);
> +	if (!save_encoder_crtcs)
>  		return -ENOMEM;
>  
> -	save_connectors = kzalloc(dev->mode_config.num_connector *
> -				sizeof(struct drm_connector), GFP_KERNEL);
> -	if (!save_connectors) {
> -		kfree(save_encoders);
> +	save_connector_encoders = kzalloc(dev->mode_config.num_connector *
> +				sizeof(struct drm_encoder *), GFP_KERNEL);
> +	if (!save_connector_encoders) {
> +		kfree(save_encoder_crtcs);
>  		return -ENOMEM;
>  	}
>  
> @@ -593,12 +593,12 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
>  	 */
>  	count = 0;
>  	drm_for_each_encoder(encoder, dev) {
> -		save_encoders[count++] = *encoder;
> +		save_encoder_crtcs[count++] = encoder->crtc;
>  	}
>  
>  	count = 0;
>  	drm_for_each_connector(connector, dev) {
> -		save_connectors[count++] = *connector;
> +		save_connector_encoders[count++] = connector->encoder;
>  	}
>  
>  	save_set.crtc = set->crtc;
> @@ -758,20 +758,20 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
>  		}
>  	}
>  
> -	kfree(save_connectors);
> -	kfree(save_encoders);
> +	kfree(save_connector_encoders);
> +	kfree(save_encoder_crtcs);
>  	return 0;
>  
>  fail:
>  	/* Restore all previous data. */
>  	count = 0;
>  	drm_for_each_encoder(encoder, dev) {
> -		*encoder = save_encoders[count++];
> +		encoder->crtc = save_encoder_crtcs[count++];
>  	}
>  
>  	count = 0;
>  	drm_for_each_connector(connector, dev) {
> -		*connector = save_connectors[count++];
> +		connector->encoder = save_connector_encoders[count++];
>  	}
>  
>  	/* after fail drop reference on all unbound connectors in set, let
> @@ -789,8 +789,8 @@ fail:
>  				      save_set.y, save_set.fb))
>  		DRM_ERROR("failed to restore config after modeset failure\n");
>  
> -	kfree(save_connectors);
> -	kfree(save_encoders);
> +	kfree(save_connector_encoders);
> +	kfree(save_encoder_crtcs);
>  	return ret;
>  }
>  EXPORT_SYMBOL(drm_crtc_helper_set_config);
> -- 
> 2.8.1
> 

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