linux-kernel - [PATCH v3 4/5] of: dynamic: add of_node

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Date:   Mon, 20 Jun 2022 12:41:22 +0200
From:   Clément Léger <clement.leger@...tlin.com>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Nathan Lynch <nathanl@...ux.ibm.com>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Daniel Henrique Barboza <danielhb413@...il.com>,
        David Gibson <david@...son.dropbear.id.au>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Ohhoon Kwon <ohoono.kwon@...sung.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        YueHaibing <yuehaibing@...wei.com>
Cc:     Clément Léger <clement.leger@...tlin.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org,
        Allan Nielsen <allan.nielsen@...rochip.com>,
        Horatiu Vultur <horatiu.vultur@...rochip.com>,
        Steen Hegelund <steen.hegelund@...rochip.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Lizhi Hou <lizhi.hou@...inx.com>
Subject: [PATCH v3 4/5] of: dynamic: add of_node_alloc()

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 | 53 ++++++++++++++++++++++++++++++++++----------
 include/linux/of.h   |  5 +++++
 2 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 9e29000571d1..422dfaa5aaa5 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -359,7 +359,9 @@ void of_node_release(struct kobject *kobj)
 	property_list_free(node->deadprops);
 	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);
 }
@@ -426,6 +428,42 @@ struct property *of_property_alloc(const char *name, const void *value,
 }
 EXPORT_SYMBOL(of_property_alloc);
 
+/**
+ * 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_node_dup() - Duplicate or create an empty device node dynamically.
  * @np:		if not NULL, contains properties to be duplicated in new node
@@ -442,24 +480,15 @@ 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) {
 		struct property *pp, *new_pp;
 		for_each_property_of_node(np, pp) {
-			new_pp = __of_prop_dup(pp, GFP_KERNEL);
+			new_pp = __of_prop_dup(pp);
 			if (!new_pp)
 				goto err_prop;
 			if (__of_add_property(node, new_pp)) {
diff --git a/include/linux/of.h b/include/linux/of.h
index 157248a77c4e..650b1ac0075b 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1464,6 +1464,7 @@ enum of_reconfig_change {
 };
 
 #ifdef CONFIG_OF_DYNAMIC
+struct device_node *of_node_alloc(const char *name);
 struct property *of_property_alloc(const char *name, const void *value,
 				   size_t len);
 void of_property_free(const struct property *prop);
@@ -1512,6 +1513,10 @@ 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
 struct property *of_property_alloc(const char *name, const void *value,
-- 
2.36.1