Hi Laurent,

On Mon, Dec 14, 2020 at 10:52:04PM +0200, Laurent Pinchart wrote:
> devm_kzalloc() is the wrong API to allocate encoders, as the lifetime of
> the encoders is tied to the DRM device, not the device to driver
> binding. drmm_kzalloc() isn't a good option either, as it would result
> in the encoder being freed before being unregistered during the managed
> cleanup of the DRM objects. Use a plain kzalloc(), and register a drmm
> action to cleanup the encoder.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>

Reviewed-by: Jacopo Mondi <jacopo+rene...@jmondi.org>

Thanks
  j

> ---
>  drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 47 ++++++++++++++---------
>  1 file changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c 
> b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> index e4bac47caf16..55a0ecf45ebb 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> @@ -8,12 +8,13 @@
>   */
>
>  #include <linux/export.h>
> +#include <linux/slab.h>
>
>  #include <drm/drm_bridge.h>
>  #include <drm/drm_crtc.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_modeset_helper_vtables.h>
>  #include <drm/drm_panel.h>
> -#include <drm/drm_simple_kms_helper.h>
>
>  #include "rcar_du_drv.h"
>  #include "rcar_du_encoder.h"
> @@ -44,6 +45,17 @@ static unsigned int rcar_du_encoder_count_ports(struct 
> device_node *node)
>       return num_ports;
>  }
>
> +static const struct drm_encoder_funcs rcar_du_encoder_funcs = {
> +};
> +
> +static void rcar_du_encoder_release(struct drm_device *dev, void *res)
> +{
> +     struct rcar_du_encoder *renc = res;
> +
> +     drm_encoder_cleanup(&renc->base);
> +     kfree(renc);
> +}
> +
>  int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>                        enum rcar_du_output output,
>                        struct device_node *enc_node)
> @@ -53,7 +65,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>       struct drm_bridge *bridge;
>       int ret;
>
> -     renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL);
> +     renc = kzalloc(sizeof(*renc), GFP_KERNEL);
>       if (renc == NULL)
>               return -ENOMEM;
>
> @@ -75,20 +87,20 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>
>               if (IS_ERR(panel)) {
>                       ret = PTR_ERR(panel);
> -                     goto done;
> +                     goto error;
>               }
>
>               bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel,
>                                                        
> DRM_MODE_CONNECTOR_DPI);
>               if (IS_ERR(bridge)) {
>                       ret = PTR_ERR(bridge);
> -                     goto done;
> +                     goto error;
>               }
>       } else {
>               bridge = of_drm_find_bridge(enc_node);
>               if (!bridge) {
>                       ret = -EPROBE_DEFER;
> -                     goto done;
> +                     goto error;
>               }
>
>               if (output == RCAR_DU_OUTPUT_LVDS0 ||
> @@ -103,28 +115,27 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>       if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
>               if (rcar_lvds_dual_link(bridge)) {
>                       ret = -ENOLINK;
> -                     goto done;
> +                     goto error;
>               }
>       }
>
> -     ret = drm_simple_encoder_init(rcdu->ddev, encoder,
> -                                   DRM_MODE_ENCODER_NONE);
> +     ret = drm_encoder_init(rcdu->ddev, encoder, &rcar_du_encoder_funcs,
> +                            DRM_MODE_ENCODER_NONE, NULL);
>       if (ret < 0)
> -             goto done;
> +             goto error;
> +
> +     ret = drmm_add_action_or_reset(rcdu->ddev, rcar_du_encoder_release,
> +                                    renc);
> +     if (ret)
> +             return ret;
>
>       /*
>        * Attach the bridge to the encoder. The bridge will create the
>        * connector.
>        */
> -     ret = drm_bridge_attach(encoder, bridge, NULL, 0);
> -     if (ret) {
> -             drm_encoder_cleanup(encoder);
> -             return ret;
> -     }
> -
> -done:
> -     if (ret < 0)
> -             devm_kfree(rcdu->dev, renc);
> +     return drm_bridge_attach(encoder, bridge, NULL, 0);
>
> +error:
> +     kfree(renc);
>       return ret;
>  }
> --
> Regards,
>
> Laurent Pinchart
>
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