Re: [linux-sunxi] [PATCH 3/3] drm/sun4i: Fix component unbinding and component master deletion

From: Chen-Yu Tsai
Date: Thu Apr 18 2019 - 11:04:00 EST


On Thu, Apr 18, 2019 at 6:27 AM Paul Kocialkowski
<paul.kocialkowski@xxxxxxxxxxx> wrote:
>
> For our component-backed driver to be properly removed, we need to
> delete the component master in sun4i_drv_remove and make sure to call
> component_unbind_all in the master's unbind so that all components are
> unbound when the master is.
>
> Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support")
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/sun4i/sun4i_drv.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
> index af07291544a4..0ea365e54de1 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_drv.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
> @@ -137,6 +137,8 @@ static void sun4i_drv_unbind(struct device *dev)
> drm_mode_config_cleanup(drm);
> of_reserved_mem_device_release(dev);
> drm_dev_put(drm);
> +
> + component_unbind_all(dev, NULL);

Shouldn't this be before drm_dev_put? Everything being in reverse order
of the complement calls in the bind function and all. The component
drivers might still be using the drm dev before they are unbound.

ChenYu

> }
>
> static const struct component_master_ops sun4i_drv_master_ops = {
> @@ -385,6 +387,8 @@ static int sun4i_drv_probe(struct platform_device *pdev)
>
> static int sun4i_drv_remove(struct platform_device *pdev)
> {
> + component_master_del(&pdev->dev, &sun4i_drv_master_ops);
> +
> return 0;
> }
>
> --
> 2.21.0
>
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