Re: [PATCH RFC V2 1/3] of: dynamic: Add of_create_node() and of_destroy_node()

[Lizhi Hou]

On 11/1/22 00:47, Christophe JAILLET wrote:
> 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@xxxxxxx>
> > Signed-off-by: Sonal Santan <sonal.santan@xxxxxxx>
> > Signed-off-by: Max Zhen <max.zhen@xxxxxxx>
> > Signed-off-by: Brian Xu <brian.xu@xxxxxxx>
> > ---
> >   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().
Ok.
> > +    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.

Will fix this. Thanks.


Lizhi

> > +    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)