[PATCH 07/12] drm: drop redundant drm_file->is_master

[Daniel Vetter]

On Wed, Jul 23, 2014 at 05:26:42PM +0200, David Herrmann wrote:
> The drm_file->is_master field is redundant as it's equivalent to:
>     drm_file->master && drm_file->master == drm_file->minor->master
> 
> 1) "=>"
>   Whenever we set drm_file->is_master, we also set:
>       drm_file->minor->master = drm_file->master;
> 
>   Whenever we clear drm_file->is_master, we also call:
>       drm_master_put(&drm_file->minor->master);
>   which implicitly clears it to NULL.
> 
> 2) "<="
>   minor->master cannot be set if it is non-NULL. Therefore, it stays as
>   is unless a file drops it.
> 
>   If minor->master is NULL, it is only set by places that also adjust
>   drm_file->is_master.
> 
> Therefore, we can safely drop is_master and replace it by an inline helper
> that matches:
>     drm_file->master && drm_file->master == drm_file->minor->master
> 
> Signed-off-by: David Herrmann <dh.herrmann at gmail.com>

Docbook for drm_is_master is missing, otherwise Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

And one question below which doesn't really matter for this patch here.
See below
-Daniel

[snip]

> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index d91e09f..e1bb585 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -387,8 +387,6 @@ struct drm_prime_file_private {
>  struct drm_file {
>  	unsigned always_authenticated :1;
>  	unsigned authenticated :1;
> -	/* Whether we're master for a minor. Protected by master_mutex */
> -	unsigned is_master :1;
>  	/* true when the client has asked us to expose stereo 3D mode flags */
>  	unsigned stereo_allowed :1;
>  	/*
> @@ -1034,7 +1032,7 @@ struct drm_device {
>  	/** \name Locks */
>  	/*@{ */
>  	struct mutex struct_mutex;	/**< For others */
> -	struct mutex master_mutex;      /**< For drm_minor::master and drm_file::is_master */
> +	struct mutex master_mutex;      /**< For drm_minor::master */
>  	/*@} */
>  
>  	/** \name Usage Counters */
> @@ -1172,6 +1170,11 @@ static inline bool drm_is_primary_client(const struct drm_file *file_priv)
>  	return file_priv->minor->type == DRM_MINOR_LEGACY;
>  }
>  

Docbook here please ...
> +static inline bool drm_is_master(const struct drm_file *file)
> +{

Hm, we don't have any means to synchronize is_master checks with
concurrent ioctls and stuff. Do we care? Orthogonal issue really.

> +	return file->master && file->master == file->minor->master;
> +}
> +
>  /******************************************************************/
>  /** \name Internal function definitions */
>  /*@{*/
> -- 
> 2.0.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch