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

From: Greg Kroah-Hartman
Date: Sun May 24 2020 - 11:30:59 EST


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.kamboju@xxxxxxxxxx>
Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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