Re: [PATCH RFC 1/2] of: dynamic: add of_node_alloc()

Frank Rowand
2022-09-16T23:15:44Z

On 8/29/22 16:43, Lizhi Hou wrote:
> From: Clément Léger <clement.leger@bootlin.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@bootlin.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);
> +

Why free node->full_name a second time?

> kfree(node->data);k> 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)
> +{

The body of this function is already implemented by __of_node_dup(NULL, ...)

> + 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;