[Intel-gfx] [PATCH 07/14] drm: Only do the hw.lock cleanup in master_relase for !MODESET

[Chris Wilson]

On Tue, Jun 14, 2016 at 08:51:02PM +0200, Daniel Vetter wrote:
> Another place gone where modern drivers could have hit
> dev->struct_mutex.
> 
> To avoid too deeply nesting control flow rework it a bit.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_auth.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
> index e015a7edb154..a58b2eb0d004 100644
> --- a/drivers/gpu/drm/drm_auth.c
> +++ b/drivers/gpu/drm/drm_auth.c
> @@ -246,11 +246,14 @@ int drm_master_open(struct drm_file *file_priv)
>  void drm_master_release(struct drm_file *file_priv)
>  {
>  	struct drm_device *dev = file_priv->minor->dev;
> +	struct drm_master *master = file_priv->master;
> +

Spare newline.

>  	mutex_lock(&dev->master_mutex);
> -	if (file_priv->is_master) {
> -		struct drm_master *master = file_priv->master;
> +	if (!file_priv->is_master)
> +		goto out_unlock;
>  
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET)) {
>  		/*
>  		 * Since the master is disappearing, so is the
>  		 * possibility to lock.
> @@ -264,19 +267,20 @@ void drm_master_release(struct drm_file *file_priv)
>  			wake_up_interruptible_all(&master->lock.lock_queue);
>  		}
>  		mutex_unlock(&dev->struct_mutex);
> +	}
>  
> -		if (file_priv->minor->master == file_priv->master) {
> -			/* drop the reference held my the minor */
> -			if (dev->driver->master_drop)
> -				dev->driver->master_drop(dev, file_priv, true);
> -			drm_master_put(&file_priv->minor->master);
> -		}
> +	if (file_priv->minor->master == file_priv->master) {
> +		/* drop the reference held my the minor */
> +		if (dev->driver->master_drop)
> +			dev->driver->master_drop(dev, file_priv, true);
> +		drm_master_put(&file_priv->minor->master);
>  	}
>  
>  	/* drop the master reference held by the file priv */
>  	if (file_priv->master)
>  		drm_master_put(&file_priv->master);
>  	file_priv->is_master = 0;
> +out_unlock:

This changes the reference counting, and from my quick scan we can have
a reference on file_priv->master but file_priv->is_master == 0.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre