patch "software node: implement software_node_unregister()" added to driver-core-testing

patch "software node: implement software_node_unregister()" added to driver-core-testing

[gregkh]

This is a note to let you know that I've just added the patch titled

    software node: implement software_node_unregister()

to my driver-core git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the driver-core-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


From 46d26819a5056f4831649c5887ad5c71a16d86f7 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sun, 24 May 2020 17:30:40 +0200
Subject: 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>
---
 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