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Message-ID: <67fdf851-961d-2f4b-591f-4939e1937e68@wanadoo.fr>
Date:   Tue, 1 Nov 2022 08:47:51 +0100
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Subject: Re: [PATCH RFC V2 1/3] of: dynamic: Add of_create_node() and
 of_destroy_node()
To:     Lizhi Hou <lizhi.hou@amd.com>, linux-pci@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        robh@kernel.org, frowand.list@gmail.com, helgaas@kernel.org
Cc:     clement.leger@bootlin.com, max.zhen@amd.com, sonal.santan@amd.com,
        larry.liu@amd.com, brian.xu@amd.com, stefano.stabellini@xilinx.com,
        trix@redhat.com
References: <1665598440-47410-1-git-send-email-lizhi.hou@amd.com>
 <1665598440-47410-2-git-send-email-lizhi.hou@amd.com>
Content-Language: fr
From:   Christophe JAILLET <christophe.jaillet@wanadoo.fr>
In-Reply-To: <1665598440-47410-2-git-send-email-lizhi.hou@amd.com>
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Precedence: bulk

Le 12/10/2022 à 20:13, Lizhi Hou a écrit :
> of_create_node() creates device node and apply to base tree dynamically.
> The parent device node and full name are required for creating the node.
> And the caller can also provide a property array for the node.
> 
> Inside this function, it creates a changeset. Then the new device node
> and properties are added to the changeset and applied to base tree. The
> pointer of this changeset is saved in device node private data.
> 
> of_destroy_node() removes the node created by of_create_node() from the
> base tree and free it. It gets the changeset pointer from device node
> private data and call of_changeset_destroy() to free everything.
> 
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
> Signed-off-by: Sonal Santan <sonal.santan@amd.com>
> Signed-off-by: Max Zhen <max.zhen@amd.com>
> Signed-off-by: Brian Xu <brian.xu@amd.com>
> ---
>   drivers/of/dynamic.c | 80 ++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/of.h   |  4 +++
>   2 files changed, 84 insertions(+)
> 
> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
> index cd3821a6444f..eca28b723706 100644
> --- a/drivers/of/dynamic.c
> +++ b/drivers/of/dynamic.c
> @@ -934,3 +934,83 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
>   	return 0;
>   }
>   EXPORT_SYMBOL_GPL(of_changeset_action);
> +
> +/**
> + * of_create_node - Dynamically create a device node and apply it to base tree
> + *
> + * @parent: Pointer to parent device node
> + * @full_name: Full name of device node
> + * @props: Pointer to property array
> + *
> + * Return: Pointer to the created device node or NULL in case of an error.
> + */
> +struct device_node *of_create_node(struct device_node *parent,
> +				   const char *full_name,
> +				   struct property *props)
> +{
> +	struct of_changeset *cset;
> +	struct property *new_pp;
> +	struct device_node *np;
> +	int ret, i;
> +
> +	cset = kzalloc(sizeof(*cset), GFP_KERNEL);

Hi,

kmalloc() would be enough. of_changeset_init() below already calls 
memset().

> +	if (!cset)
> +		return NULL;
> +
> +	of_changeset_init(cset);
> +
> +	np = __of_node_dup(NULL, full_name);
> +	if (!np)
> +		goto failed;

'cset' seems to be leaking if __of_node_dup() fails.

> +	np->parent = parent;
> +
> +	ret = of_changeset_attach_node(cset, np);
> +	if (ret)
> +		goto failed;
> +
> +	if (props) {
> +		for (i = 0; props[i].name; i++) {
> +			new_pp = __of_prop_dup(&props[i], GFP_KERNEL);
> +			if (!new_pp)
> +				goto failed;
> +			ret = of_changeset_add_property(cset, np, new_pp);
> +			if (ret) {
> +				kfree(new_pp->name);
> +				kfree(new_pp->value);
> +				kfree(new_pp);
> +				goto failed;
> +			}
> +		}
> +	}
> +
> +	ret = of_changeset_apply(cset);
> +	if (ret)
> +		goto failed;
> +
> +	np->data = cset;
> +
> +	return np;
> +
> +failed:
> +	of_changeset_destroy(cset);
> +	if (np)
> +		of_node_put(np);
> +
> +	return NULL;
> +}
> +
> +/**
> + * of_destroy_node - Destroy a dynamically created device node
> + *
> + * @np: Pointer to dynamically created device node
> + *
> + */
> +void of_destroy_node(struct device_node *np)
> +{
> +	struct of_changeset *cset;
> +
> +	cset = (struct of_changeset *)np->data;
> +	of_changeset_destroy(cset);
> +	of_node_put(np);
> +	kfree(cset);
> +}
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 766d002bddb9..493ef957c1a8 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -1475,6 +1475,10 @@ extern int of_changeset_revert(struct of_changeset *ocs);
>   extern int of_changeset_action(struct of_changeset *ocs,
>   		unsigned long action, struct device_node *np,
>   		struct property *prop);
> +struct device_node *of_create_node(struct device_node *parent,
> +				   const char *full_name,
> +				   struct property *props);
> +void of_destroy_node(struct device_node *np);
>   
>   static inline int of_changeset_attach_node(struct of_changeset *ocs,
>   		struct device_node *np)