Re: [PATCH v2 03/21] drm: Make drm_connector_register() safe against multiple calls

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, May 30, 2016 at 09:38:21AM +0100, Chris Wilson wrote:
> Protect against drivers that may try to register the connector more
> than once, or who try to unregister it multiple times.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: dri-devel@lists.freedesktop.org
> ---
>  drivers/gpu/drm/drm_crtc.c | 9 +++++++++
>  include/drm/drm_crtc.h     | 1 +
>  2 files changed, 10 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 81641544ac3e..8b9ee921a9e1 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -1030,6 +1030,9 @@ int drm_connector_register(struct drm_connector *connector)
>  {
>  	int ret;
>  
> +	if (connector->registered)
> +		return 0;
> +
>  	ret = drm_sysfs_connector_add(connector);
>  	if (ret)
>  		return ret;
> @@ -1047,6 +1050,7 @@ int drm_connector_register(struct drm_connector *connector)
>  
>  	drm_mode_object_register(connector->dev, &connector->base);
>  
> +	connector->registered = true;
>  	return 0;
>  
>  err_debugfs:
> @@ -1065,11 +1069,16 @@ EXPORT_SYMBOL(drm_connector_register);
>   */
>  void drm_connector_unregister(struct drm_connector *connector)
>  {
> +	if (!connector->registered)
> +		return;
> +
>  	if (connector->funcs->early_unregister)
>  		connector->funcs->early_unregister(connector);
>  
>  	drm_sysfs_connector_remove(connector);
>  	drm_debugfs_connector_remove(connector);
> +
> +	connector->registered = false;
>  }
>  EXPORT_SYMBOL(drm_connector_unregister);
>  
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 77b775cff4e7..35e47eea5ee1 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1212,6 +1212,7 @@ struct drm_connector {
>  	bool interlace_allowed;
>  	bool doublescan_allowed;
>  	bool stereo_allowed;
> +	bool registered;

Needs kerneldoc for this on, with that fixed

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

>  	struct list_head modes; /* list of modes on this connector */
>  
>  	enum drm_connector_status status;
> -- 
> 2.8.1
> 
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> Intel-gfx@lists.freedesktop.org
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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