[PATCH 3/6] drm: Refactor drm_core_init error path

[Dmitry Baryshkov]

On Sun, Sep 08, 2024 at 02:10:30PM GMT, Heiner Kallweit wrote:
> These changes make the error path a little more robust, because exit
> steps in drm_core_exit() don't have to ensure any longer that they
> work properly even if the associated init step wasn't executed.

Please use imperative style when describing changes. E.g. "Do this and
that because of ABCDEF". See
Documentation/process/submitting-patches.rst

> In addition these changes allow to annotate a few functions as __exit,
> saving some memory if drm is built-in.

This should be a separate commit.

> 
> Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
> ---
>  drivers/accel/drm_accel.c                |  2 +-
>  drivers/gpu/drm/drm_drv.c                | 18 ++++++++++++------
>  drivers/gpu/drm/drm_panic.c              |  4 ++--
>  drivers/gpu/drm/drm_privacy_screen_x86.c |  2 +-
>  drivers/gpu/drm/drm_sysfs.c              |  2 --
>  5 files changed, 16 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/accel/drm_accel.c b/drivers/accel/drm_accel.c
> index aa826033b..25fdbea36 100644
> --- a/drivers/accel/drm_accel.c
> +++ b/drivers/accel/drm_accel.c
> @@ -191,7 +191,7 @@ static const struct file_operations accel_stub_fops = {
>  	.llseek = noop_llseek,
>  };
>  
> -void accel_core_exit(void)
> +void __exit accel_core_exit(void)
>  {
>  	unregister_chrdev(ACCEL_MAJOR, "accel");
>  	debugfs_remove(accel_debugfs_root);
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index ac30b0ec9..ea59994e5 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -1062,7 +1062,7 @@ static const struct file_operations drm_stub_fops = {
>  	.llseek = noop_llseek,
>  };
>  
> -static void drm_core_exit(void)
> +static void __exit drm_core_exit(void)
>  {
>  	drm_privacy_screen_lookup_exit();
>  	drm_panic_exit();
> @@ -1084,18 +1084,18 @@ static int __init drm_core_init(void)
>  	ret = drm_sysfs_init();
>  	if (ret < 0) {
>  		DRM_ERROR("Cannot create DRM class: %d\n", ret);
> -		goto error;
> +		goto err_ida;
>  	}
>  
>  	drm_debugfs_root = debugfs_create_dir("dri", NULL);
>  
>  	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
>  	if (ret < 0)
> -		goto error;
> +		goto err_debugfs;
>  
>  	ret = accel_core_init();
>  	if (ret < 0)
> -		goto error;
> +		goto err_chrdev;
>  
>  	drm_panic_init();
>  
> @@ -1106,8 +1106,14 @@ static int __init drm_core_init(void)
>  	DRM_DEBUG("Initialized\n");
>  	return 0;
>  
> -error:
> -	drm_core_exit();
> +err_chrdev:
> +	unregister_chrdev(DRM_MAJOR, "drm");
> +err_debugfs:
> +	debugfs_remove(drm_debugfs_root);
> +	drm_sysfs_destroy();
> +err_ida:
> +	WARN_ON(!xa_empty(&drm_minors_xa));
> +	drm_connector_ida_destroy();
>  	return ret;
>  }
>  
> diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
> index 74412b7bf..d00fdb12d 100644
> --- a/drivers/gpu/drm/drm_panic.c
> +++ b/drivers/gpu/drm/drm_panic.c
> @@ -679,7 +679,7 @@ static void __init drm_panic_qr_init(void)
>  				   GFP_KERNEL);
>  }
>  
> -static void drm_panic_qr_exit(void)
> +static void __exit drm_panic_qr_exit(void)
>  {
>  	kfree(qrbuf1);
>  	qrbuf1 = NULL;
> @@ -1058,7 +1058,7 @@ void __init drm_panic_init(void)
>  /**
>   * drm_panic_exit() - Free the resources taken by drm_panic_exit()
>   */
> -void drm_panic_exit(void)
> +void __exit drm_panic_exit(void)
>  {
>  	drm_panic_qr_exit();
>  }
> diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c
> index 72ed40e49..6be96a0cc 100644
> --- a/drivers/gpu/drm/drm_privacy_screen_x86.c
> +++ b/drivers/gpu/drm/drm_privacy_screen_x86.c
> @@ -98,7 +98,7 @@ void __init drm_privacy_screen_lookup_init(void)
>  	}
>  }
>  
> -void drm_privacy_screen_lookup_exit(void)
> +void __exit drm_privacy_screen_lookup_exit(void)
>  {
>  	if (arch_lookup.provider)
>  		drm_privacy_screen_lookup_remove(&arch_lookup);
> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> index a713f0500..f8577043e 100644
> --- a/drivers/gpu/drm/drm_sysfs.c
> +++ b/drivers/gpu/drm/drm_sysfs.c
> @@ -155,8 +155,6 @@ int drm_sysfs_init(void)
>   */
>  void drm_sysfs_destroy(void)
>  {
> -	if (IS_ERR_OR_NULL(drm_class))
> -		return;
>  	drm_sysfs_acpi_unregister();
>  	class_destroy(drm_class);
>  	drm_class = NULL;
> -- 
> 2.46.0
> 
> 

-- 
With best wishes
Dmitry