of_overlay_remove_all() which will remove every single one in the correct
order.
+In addition, there is the option to register notifiers that get called on
+overlay operations. See of_overlay_notifier_register/unregister and
+enum of_overlay_notify_action for details.
+
+Note that a notifier callback is not supposed to store pointers to a device
+tree node or its content beyond OF_OVERLAY_POST_REMOVE corresponding to the
+respective node it received.
+
Overlay DTS Format
------------------
static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain);
+/**
+ * of_overlay_notifier_register() - Register notifier for overlay operations
+ * @nb: Notifier block to register
+ *
+ * Register for notification on overlay operations on device tree nodes. The
+ * reported actions definied by @of_reconfig_change. The notifier callback
+ * furthermore receives a pointer to the affected device tree node.
+ *
+ * Note that a notifier callback is not supposed to store pointers to a device
+ * tree node or its content beyond @OF_OVERLAY_POST_REMOVE corresponding to the
+ * respective node it received.
+ */
int of_overlay_notifier_register(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&overlay_notify_chain, nb);
}
EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
+/**
+ * of_overlay_notifier_register() - Unregister notifier for overlay operations
+ * @nb: Notifier block to unregister
+ */
int of_overlay_notifier_unregister(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&overlay_notify_chain, nb);
of_node_put(ovcs->fragments[i].overlay);
}
kfree(ovcs->fragments);
-
/*
- * TODO
- *
- * would like to: kfree(ovcs->overlay_tree);
- * but can not since drivers may have pointers into this data
- *
- * would like to: kfree(ovcs->fdt);
- * but can not since drivers may have pointers into this data
+ * There should be no live pointers into ovcs->overlay_tree and
+ * ovcs->fdt due to the policy that overlay notifiers are not allowed
+ * to retain pointers into the overlay devicetree.
*/
-
+ kfree(ovcs->overlay_tree);
+ kfree(ovcs->fdt);
kfree(ovcs);
}