linux-kernel - [PATCH RFC 1/2] of: dynamic: add of_node

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Date:   Mon, 29 Aug 2022 14:43:36 -0700
From:   Lizhi Hou <lizhi.hou@....com>
To:     <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <robh@...nel.org>,
        <frowand.list@...il.com>, <helgaas@...nel.org>
CC:     Clément Léger <clement.leger@...tlin.com>,
        <max.zhen@....com>, <sonal.santan@....com>, <larry.liu@....com>,
        <brian.xu@....com>, <stefano.stabellini@...inx.com>,
        <trix@...hat.com>
Subject: [PATCH RFC 1/2] of: dynamic: add of_node_alloc()

From: Clément Léger <clement.leger@...tlin.com>

Add of_node_alloc() which allows to create nodes. The node full_name
field is allocated as part of the node allocation and the kfree() for
this field is checked at release time to allow users using their own
allocated name.

Signed-off-by: Clément Léger <clement.leger@...tlin.com>
---
 drivers/of/dynamic.c | 50 +++++++++++++++++++++++++++++++++++---------
 include/linux/of.h   |  7 +++++++
 2 files changed, 47 insertions(+), 10 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index cd3821a6444f..0e08283fd4fd 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -362,10 +362,49 @@ void of_node_release(struct kobject *kobj)
 	fwnode_links_purge(of_fwnode_handle(node));
 
 	kfree(node->full_name);
+	if (node->full_name != (const char *)(node + 1))
+		kfree(node->full_name);
+
 	kfree(node->data);
 	kfree(node);
 }
 
+/**
+ * of_node_alloc - Allocate a node dynamically.
+ * @name:	Node name
+ *
+ * Create a node by dynamically allocating the memory of both the
+ * node structure and the node name & contents. The node's
+ * flags have the OF_DYNAMIC & OF_DETACHED bit set so that we can
+ * differentiate between dynamically allocated nodes and not.
+ *
+ * Return: The newly allocated node or NULL on out of memory error.
+ */
+struct device_node *of_node_alloc(const char *name)
+{
+	struct device_node *node;
+	int name_len = 0;
+
+	if (name)
+		name_len = strlen(name) + 1;
+
+	node = kzalloc(sizeof(*node) + name_len, GFP_KERNEL);
+	if (!node)
+		return NULL;
+
+	if (name) {
+		node->full_name = (const char *)(node + 1);
+		strcpy((char *)node->full_name, name);
+	}
+
+	of_node_set_flag(node, OF_DYNAMIC);
+	of_node_set_flag(node, OF_DETACHED);
+	of_node_init(node);
+
+	return node;
+}
+EXPORT_SYMBOL(of_node_alloc);
+
 /**
  * __of_prop_dup - Copy a property dynamically.
  * @prop:	Property to copy
@@ -426,18 +465,9 @@ struct device_node *__of_node_dup(const struct device_node *np,
 {
 	struct device_node *node;
 
-	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	node = of_node_alloc(full_name);
 	if (!node)
 		return NULL;
-	node->full_name = kstrdup(full_name, GFP_KERNEL);
-	if (!node->full_name) {
-		kfree(node);
-		return NULL;
-	}
-
-	of_node_set_flag(node, OF_DYNAMIC);
-	of_node_set_flag(node, OF_DETACHED);
-	of_node_init(node);
 
 	/* Iterate over and duplicate all properties */
 	if (np) {
diff --git a/include/linux/of.h b/include/linux/of.h
index 766d002bddb9..fc71e0355f05 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1462,6 +1462,8 @@ enum of_reconfig_change {
 };
 
 #ifdef CONFIG_OF_DYNAMIC
+struct device_node *of_node_alloc(const char *name);
+
 extern int of_reconfig_notifier_register(struct notifier_block *);
 extern int of_reconfig_notifier_unregister(struct notifier_block *);
 extern int of_reconfig_notify(unsigned long, struct of_reconfig_data *rd);
@@ -1506,6 +1508,11 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
 	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
 }
 #else /* CONFIG_OF_DYNAMIC */
+static inline struct device_node *of_node_alloc(const char *name)
+{
+	return NULL;
+}
+
 static inline int of_reconfig_notifier_register(struct notifier_block *nb)
 {
 	return -EINVAL;
-- 
2.27.0