software node: implement software_node_unregister()

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")
Cc: stable <stable@vger.kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20200524153041.2361-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 1 deletions

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