linux-kernel - Re: [PATCH v2 05/12] software_node: unregister software

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Date:   Mon, 21 Dec 2020 11:21:16 +0200
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Daniel Scally <djrscally@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-media@...r.kernel.org, devel@...ica.org, rjw@...ysocki.net,
        lenb@...nel.org, gregkh@...uxfoundation.org, yong.zhi@...el.com,
        bingbu.cao@...el.com, tian.shu.qiu@...el.com, mchehab@...nel.org,
        robert.moore@...el.com, erik.kaneda@...el.com, pmladek@...e.com,
        rostedt@...dmis.org, sergey.senozhatsky@...il.com,
        andriy.shevchenko@...ux.intel.com, linux@...musvillemoes.dk,
        laurent.pinchart+renesas@...asonboard.com,
        jacopo+renesas@...ndi.org, kieran.bingham+renesas@...asonboard.com,
        linus.walleij@...aro.org, heikki.krogerus@...ux.intel.com,
        kitakar@...il.com, jorhand@...ux.microsoft.com,
        kernel test robot <lkp@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH v2 05/12] software_node: unregister software_nodes in
 reverse order

Hi Daniel,

On Thu, Dec 17, 2020 at 11:43:30PM +0000, Daniel Scally wrote:
> To maintain consistency with software_node_unregister_nodes(), reverse
> the order in which the software_node_unregister_node_group() function
> unregisters nodes.
> 
> Reported-by: kernel test robot <lkp@...el.com>
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Signed-off-by: Daniel Scally <djrscally@...il.com>
> ---
> Changes in v2:
> 
> 	- Initialised i properly
> 
>  drivers/base/swnode.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index cfd1faea48a7..2b90d380039b 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -778,16 +778,22 @@ EXPORT_SYMBOL_GPL(software_node_register_node_group);
>   * software_node_unregister_node_group - Unregister a group of software nodes
>   * @node_group: NULL terminated array of software node pointers to be unregistered
>   *
> - * Unregister multiple software nodes at once.
> + * Unregister multiple software nodes at once. The array will be unwound in
> + * reverse order (I.E. last entry first) and thus if any member of the array
> + * has its .parent member set then they should appear later in the array such
> + * that they are unregistered first.
>   */
>  void software_node_unregister_node_group(const struct software_node **node_group)
>  {
> -	unsigned int i;
> +	unsigned int i = 0;
>  
>  	if (!node_group)
>  		return;
>  
> -	for (i = 0; node_group[i]; i++)
> +	while (node_group[i]->name)

Why is this change made? node_group is a NULL-terminated array, and the
above accesses the name pointer on each entry before checking the entry is
non-NULL. Or do I miss something here?

> +		i++;
> +
> +	while (i--)
>  		software_node_unregister(node_group[i]);
>  }
>  EXPORT_SYMBOL_GPL(software_node_unregister_node_group);

-- 
Regards,

Sakari Ailus