linux-kernel - Re: [PATCH] drm/auth: Move master pointer from drm_device to drm

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Date:   Thu, 17 Jun 2021 21:17:48 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Qiang Ma <maqianga@...ontech.com>
Cc:     maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        tzimmermann@...e.de, airlied@...ux.ie, daniel@...ll.ch,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/auth: Move master pointer from drm_device to drm_file

On Thu, Jun 17, 2021 at 05:47:33PM +0800, Qiang Ma wrote:
> The drm_file pointer clears to zero during multi-user switching,
> so it needs to call drm_new_set_master for master pointer from drm_file.

That sounds like a bug. drm_file->master should be always the same -
either you become a new stand-alone thing, our you get linked to the
current master.

Or I'm completely missing what you're trying to fix here.
-Daniel

> 
> Signed-off-by: Qiang Ma <maqianga@...ontech.com>
> ---
>  drivers/gpu/drm/drm_auth.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
> index f2d46b7ac6f9..02431af6d0c5 100644
> --- a/drivers/gpu/drm/drm_auth.c
> +++ b/drivers/gpu/drm/drm_auth.c
> @@ -302,7 +302,7 @@ int drm_master_open(struct drm_file *file_priv)
>  	/* if there is no current master make this fd it, but do not create
>  	 * any master object for render clients */
>  	mutex_lock(&dev->master_mutex);
> -	if (!dev->master)
> +	if (!file_priv->master)
>  		ret = drm_new_set_master(dev, file_priv);
>  	else
>  		file_priv->master = drm_master_get(dev->master);
> -- 
> 2.20.1
> 
> 
> 

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