linux-kernel - Re: [PATCH v5 2/9] drm/bridge-connector: switch to using drmm allocations

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Date: Mon, 10 Jun 2024 10:04:40 +0200
From: Maxime Ripard <mripard@...nel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Daniel Vetter <daniel@...ll.ch>, Rob Clark <robdclark@...il.com>, 
	Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org, 
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/9] drm/bridge-connector: switch to using drmm
 allocations

Hi,

On Fri, Jun 07, 2024 at 04:22:59PM GMT, Dmitry Baryshkov wrote:
> Turn drm_bridge_connector to using drmm_kzalloc() and
> drmm_connector_init() and drop the custom destroy function. The
> drm_connector_unregister() and fwnode_handle_put() are already handled
> by the drm_connector_cleanup() and so are safe to be dropped.
> 
> Acked-by: Maxime Ripard <mripard@...nel.org>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
>  drivers/gpu/drm/drm_bridge_connector.c | 23 +++++------------------
>  1 file changed, 5 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
> index 982552c9f92c..e093fc8928dc 100644
> --- a/drivers/gpu/drm/drm_bridge_connector.c
> +++ b/drivers/gpu/drm/drm_bridge_connector.c
> @@ -15,6 +15,7 @@
>  #include <drm/drm_connector.h>
>  #include <drm/drm_device.h>
>  #include <drm/drm_edid.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_modeset_helper_vtables.h>
>  #include <drm/drm_probe_helper.h>
>  
> @@ -193,19 +194,6 @@ drm_bridge_connector_detect(struct drm_connector *connector, bool force)
>  	return status;
>  }
>  
> -static void drm_bridge_connector_destroy(struct drm_connector *connector)
> -{
> -	struct drm_bridge_connector *bridge_connector =
> -		to_drm_bridge_connector(connector);
> -
> -	drm_connector_unregister(connector);
> -	drm_connector_cleanup(connector);
> -
> -	fwnode_handle_put(connector->fwnode);
> -
> -	kfree(bridge_connector);
> -}
> -
>  static void drm_bridge_connector_debugfs_init(struct drm_connector *connector,
>  					      struct dentry *root)
>  {
> @@ -224,7 +212,6 @@ static const struct drm_connector_funcs drm_bridge_connector_funcs = {
>  	.reset = drm_atomic_helper_connector_reset,
>  	.detect = drm_bridge_connector_detect,
>  	.fill_modes = drm_helper_probe_single_connector_modes,
> -	.destroy = drm_bridge_connector_destroy,
>  	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
>  	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>  	.debugfs_init = drm_bridge_connector_debugfs_init,
> @@ -328,7 +315,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
>  	int connector_type;
>  	int ret;
>  
> -	bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL);
> +	bridge_connector = drmm_kzalloc(drm, sizeof(*bridge_connector), GFP_KERNEL);

So you make destroy's kfree call unnecessary here ...

>  	if (!bridge_connector)
>  		return ERR_PTR(-ENOMEM);
>  
> @@ -383,9 +370,9 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
>  		return ERR_PTR(-EINVAL);
>  	}
>  
> -	ret = drm_connector_init_with_ddc(drm, connector,
> -					  &drm_bridge_connector_funcs,
> -					  connector_type, ddc);
> +	ret = drmm_connector_init(drm, connector,
> +				  &drm_bridge_connector_funcs,
> +				  connector_type, ddc);

... and here of drm_connector_cleanup.

drm_connector_unregister wasn't needed, so can ignore it, but you leak a reference to
connector->fwnode since you don't call fwnode_handle_put anymore.

We should register a drmm action right below the call to fwnode_handle_get too.

Maxime

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