Re: [PATCH v2] media:v4l2-async:add debugfs under CONFIG_DEBUG_FS

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Luo,

Thanks for the patch.

On Wed, Jan 21, 2026 at 11:14:56AM +0800, luo.liu wrote:
> All debugfs-related code is guarded by CONFIG_DEBUG_FS to avoid
> bloating the kernel when debugfs is disabled.
> 
> Signed-off-by: luo.liu <luo.liu.linux@163.com>
> ---
>  drivers/media/v4l2-core/v4l2-async.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 1c08bba9ecb9..f6a1a57149ba 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -947,6 +947,7 @@ v4l2_async_nf_name(struct v4l2_async_notifier *notifier)
>  		return "nil";
>  }
>  
> +#ifdef CONFIG_DEBUG_FS
>  static int pending_subdevs_show(struct seq_file *s, void *data)
>  {
>  	struct v4l2_async_notifier *notif;
> @@ -967,20 +968,25 @@ static int pending_subdevs_show(struct seq_file *s, void *data)
>  DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
>  
>  static struct dentry *v4l2_async_debugfs_dir;
> +#endif

This part seems reasonable...

>  
>  static int __init v4l2_async_init(void)
>  {
> +#ifdef CONFIG_DEBUG_FS
>  	v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
>  	debugfs_create_file("pending_async_subdevices", 0444,
>  			    v4l2_async_debugfs_dir, NULL,
>  			    &pending_subdevs_fops);
>  
> +#endif
>  	return 0;
>  }
>  
>  static void __exit v4l2_async_exit(void)
>  {
> +#ifdef CONFIG_DEBUG_FS
>  	debugfs_remove_recursive(v4l2_async_debugfs_dir);
> +#endif
>  }

But are the two latter #if's useful? Looks like the compiler should
optimise these out...

>  
>  subsys_initcall(v4l2_async_init);
> 
> base-commit: d08c85ac8894995d4b0d8fb48d2f6a3e53cd79ab

-- 
Kind regards,

Sakari Ailus