Commit d9b1103b authored by Daniel Scally's avatar Daniel Scally Committed by Mauro Carvalho Chehab
Browse files

media: software_node: Enforce parent before child ordering of nodes arrays 



Registering software_nodes with the .parent member set to point to a
currently unregistered software_node has the potential for problems,
so enforce parent -> child ordering in arrays passed in to
software_node_register_nodes().

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
software_node_unregister_nodes() unregisters software_nodes.

Suggested-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarDaniel Scally <djrscally@gmail.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent acd418bf

drivers/base/swnode.c

+30 −12
Original line number Diff line number Diff line
@@ -692,7 +692,11 @@ swnode_register(const struct software_node *node, struct swnode *parent, 
 * software_node_register_nodes - Register an array of software nodes

 * @nodes: Zero terminated array of software nodes to be registered

 *

 * Register multiple software nodes at once.

 * Register multiple software nodes at once. If any node in the array

 * has its .parent pointer set (which can only be to another software_node),

 * then its parent **must** have been registered before it is; either outside

 * of this function or by ordering the array such that parent comes before

 * child.

 */

int software_node_register_nodes(const struct software_node *nodes)

{
@@ -700,14 +704,23 @@ int software_node_register_nodes(const struct software_node *nodes) 
	int i;



	for (i = 0; nodes[i].name; i++) {

		ret = software_node_register(&nodes[i]);

		if (ret) {

			software_node_unregister_nodes(nodes);

			return ret;

		const struct software_node *parent = nodes[i].parent;



		if (parent && !software_node_to_swnode(parent)) {

			ret = -EINVAL;

			goto err_unregister_nodes;

		}



		ret = software_node_register(&nodes[i]);

		if (ret)

			goto err_unregister_nodes;

	}



	return 0;



err_unregister_nodes:

	software_node_unregister_nodes(nodes);

	return ret;

}

EXPORT_SYMBOL_GPL(software_node_register_nodes);
@@ -715,18 +728,23 @@ 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

 *

 * Unregister multiple software nodes at once.

 * Unregister multiple software nodes at once. 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.

 *

 * 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);