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

Daniel Scally
2020-11-30T13:34:24Z

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>
---
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);
--
2.25.1