linux-kernel - Re: [PATCH] iio: core: use debugfs_remove

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Date:   Sun, 15 Dec 2019 16:25:25 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Lars-Peter Clausen <lars@...afoo.de>
Subject: Re: [PATCH] iio: core: use debugfs_remove_recursive() on IIO unload

On Wed, 11 Dec 2019 16:59:03 +0200
Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:

> From: Lars-Peter Clausen <lars@...afoo.de>
> 
> The debugfs dir may have multiple files/dirs attached to it. Use
> debugfs_remove_recursive() to clean it up when the IIO module unloads.
> 
> Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> ---
> 
> Note: note sure if this needs a Fixes tag. It's been in here for ages now,
>       so it may not be a big issue.

There is some argument in favour of doing this as a defensive measure, but
in current IIO debugfs directories are only created by drivers that call
(indirectly) iio_device_register_debugfs and those must call
(again indirectly) iio_device_unregister_debugfs which has called
the recursive free on everything in their directories.  So unless something
very odd is going on this isn't a bug.

Am I missing something?


> 
>  drivers/iio/industrialio-core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 9a3579943574..dab67cb69fe6 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -292,7 +292,7 @@ static void __exit iio_exit(void)
>  	if (iio_devt)
>  		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
>  	bus_unregister(&iio_bus_type);
> -	debugfs_remove(iio_debugfs_dentry);
> +	debugfs_remove_recursive(iio_debugfs_dentry);
>  }
>  
>  #if defined(CONFIG_DEBUG_FS)