Re: [PATCH 05/18] software_node: Alter software_node_unregister_nodes() to unregister the array in reverse order

Laurent Pinchart
2020-11-30T16:15:42Z

Hi Daniel,

Thank you for the patch.

On Mon, Nov 30, 2020 at 01:31:16PM +0000, Daniel Scally wrote:
> Software nodes that are children of another software node should be
> unregistered before their parent. To allow easy unregistering of an array
> of software_nodes ordered parent to child, reverse the order in which
> this function unregisters software_nodes.
>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> Changes since RFC v3:
>
> Switched this functionality from a new function to replacing
> the existing software_nodes_unregister_nodes()
>
> drivers/base/swnode.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index af7930b3679e..d39e1c76d98d 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -720,20 +720,25 @@ EXPORT_SYMBOL_GPL(software_node_register_nodes);
>
> /**
> * software_node_unregister_nodes - Unregister an array of software nodes
> - * @nodes: Zero terminated array of software nodes to be unregistered
> + * @nodes: Zero terminated array of software nodes to be unregistered. If
> + * parent pointers are set up in any of the software nodes then the array
> + * MUST be ordered such that parents come before their children.
> *
> * Unregister multiple software nodes at once.
> *
> - * NOTE: Be careful using this call if the nodes had parent pointers set up in
> - * them before registering. If so, it is wiser to remove the nodes
> - * individually, in the correct order (child before parent) instead of relying
> - * on the sequential order of the list of nodes in the array.
> + * NOTE: If you are uncertain whether the array is ordered such that
> + * parents will be unregistered before their children, it is wiser to
> + * remove the nodes individually, in the correct order (child before
> + * parent).
> */
> void software_node_unregister_nodes(const struct software_node *nodes)
> {
> - int i;
> + unsigned int i = 0;
> +
> + while (nodes[i].name)
> + i++;
>
> - for (i = 0; nodes[i].name; i++)
> + while (i--)
> software_node_unregister(&nodes[i]);
> }
> EXPORT_SYMBOL_GPL(software_node_unregister_nodes);

--
Regards,

Laurent Pinchart