[PATCH 1/2] software node: implement software_node_unregister()

[Greg Kroah-Hartman]

Sometimes it is better to unregister individual nodes instead of trying
to do them all at once with software_node_unregister_nodes(), so create
software_node_unregister() so that you can unregister them one at a
time.

This is especially important when creating nodes in a hierarchy, with
parent -> children representations.  Children always need to be removed
before a parent is, as the swnode logic assumes this is going to be the
case.

Fix up the lib/test_printf.c fwnode_pointer() test which to use this new
function as it had the problem of tearing things down in the backwards
order.

Fixes: f1ce39df508d ("lib/test_printf: Add tests for %pfw printk modifier")
Reported-by: Naresh Kamboju <naresh.kamb...@linaro.org>
Reported-by: kernel test robot <rong.a.c...@intel.com>
Cc: stable <sta...@vger.kernel.org>
Cc: Andy Shevchenko <andriy.shevche...@linux.intel.com>
Cc: Brendan Higgins <brendanhigg...@google.com>
Cc: Dmitry Torokhov <dmitry.torok...@gmail.com>
Cc: Heikki Krogerus <heikki.kroge...@linux.intel.com>
Cc: Petr Mladek <pmla...@suse.com>
Cc: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Cc: Randy Dunlap <rdun...@infradead.org>
Cc: Rasmus Villemoes <li...@rasmusvillemoes.dk>
Cc: Sakari Ailus <sakari.ai...@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/base/swnode.c    | 27 +++++++++++++++++++++------
 include/linux/property.h |  1 +
 lib/test_printf.c        |  4 +++-
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index de8d3543e8fe..770b1f47a625 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -712,17 +712,18 @@ EXPORT_SYMBOL_GPL(software_node_register_nodes);
  * @nodes: Zero terminated array of software nodes to be unregistered
  *
  * 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.
  */
 void software_node_unregister_nodes(const struct software_node *nodes)
 {
-       struct swnode *swnode;
        int i;
 
-       for (i = 0; nodes[i].name; i++) {
-               swnode = software_node_to_swnode(&nodes[i]);
-               if (swnode)
-                       fwnode_remove_software_node(&swnode->fwnode);
-       }
+       for (i = 0; nodes[i].name; i++)
+               software_node_unregister(&nodes[i]);
 }
 EXPORT_SYMBOL_GPL(software_node_unregister_nodes);
 
@@ -741,6 +742,20 @@ int software_node_register(const struct software_node 
*node)
 }
 EXPORT_SYMBOL_GPL(software_node_register);
 
+/**
+ * software_node_unregister - Unregister static software node
+ * @node: The software node to be unregistered
+ */
+void software_node_unregister(const struct software_node *node)
+{
+       struct swnode *swnode;
+
+       swnode = software_node_to_swnode(node);
+       if (swnode)
+               fwnode_remove_software_node(&swnode->fwnode);
+}
+EXPORT_SYMBOL_GPL(software_node_unregister);
+
 struct fwnode_handle *
 fwnode_create_software_node(const struct property_entry *properties,
                            const struct fwnode_handle *parent)
diff --git a/include/linux/property.h b/include/linux/property.h
index d86de017c689..0d4099b4ce1f 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -441,6 +441,7 @@ int software_node_register_nodes(const struct software_node 
*nodes);
 void software_node_unregister_nodes(const struct software_node *nodes);
 
 int software_node_register(const struct software_node *node);
+void software_node_unregister(const struct software_node *node);
 
 int software_node_notify(struct device *dev, unsigned long action);
 
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 6b1622f4d7c2..fc63b8959d42 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -637,7 +637,9 @@ static void __init fwnode_pointer(void)
        test(second_name, "%pfwP", software_node_fwnode(&softnodes[1]));
        test(third_name, "%pfwP", software_node_fwnode(&softnodes[2]));
 
-       software_node_unregister_nodes(softnodes);
+       software_node_unregister(&softnodes[2]);
+       software_node_unregister(&softnodes[1]);
+       software_node_unregister(&softnodes[0]);
 }
 
 static void __init
-- 
2.26.2