Re: [PATCH v2 1/6] software node: Free resources explicitly when swnode_register() fails

From: Heikki Krogerus
Date: Wed Mar 31 2021 - 07:07:03 EST


On Mon, Mar 29, 2021 at 06:12:02PM +0300, Andy Shevchenko wrote:
> Currently we have a slightly twisted logic in swnode_register().
> It frees resources that it doesn't allocate on error path and
> in once case it relies on the ->release() implementation.
>
> Untwist the logic by freeing resources explicitly when swnode_register()
> fails. Currently it happens only in fwnode_create_software_node().
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

It all looks OK to me. FWIW, for the whole series:

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
> v2: no changes
> drivers/base/swnode.c | 29 +++++++++++++++++------------
> 1 file changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index fa3719ef80e4..456f5fe58b58 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -767,22 +767,19 @@ swnode_register(const struct software_node *node, struct swnode *parent,
> int ret;
>
> swnode = kzalloc(sizeof(*swnode), GFP_KERNEL);
> - if (!swnode) {
> - ret = -ENOMEM;
> - goto out_err;
> - }
> + if (!swnode)
> + return ERR_PTR(-ENOMEM);
>
> ret = ida_simple_get(parent ? &parent->child_ids : &swnode_root_ids,
> 0, 0, GFP_KERNEL);
> if (ret < 0) {
> kfree(swnode);
> - goto out_err;
> + return ERR_PTR(ret);
> }
>
> swnode->id = ret;
> swnode->node = node;
> swnode->parent = parent;
> - swnode->allocated = allocated;
> swnode->kobj.kset = swnode_kset;
> fwnode_init(&swnode->fwnode, &software_node_ops);
>
> @@ -803,16 +800,17 @@ swnode_register(const struct software_node *node, struct swnode *parent,
> return ERR_PTR(ret);
> }
>
> + /*
> + * Assign the flag only in the successful case, so
> + * the above kobject_put() won't mess up with properties.
> + */
> + swnode->allocated = allocated;
> +
> if (parent)
> list_add_tail(&swnode->entry, &parent->children);
>
> kobject_uevent(&swnode->kobj, KOBJ_ADD);
> return &swnode->fwnode;
> -
> -out_err:
> - if (allocated)
> - property_entries_free(node->properties);
> - return ERR_PTR(ret);
> }
>
> /**
> @@ -963,6 +961,7 @@ struct fwnode_handle *
> fwnode_create_software_node(const struct property_entry *properties,
> const struct fwnode_handle *parent)
> {
> + struct fwnode_handle *fwnode;
> struct software_node *node;
> struct swnode *p = NULL;
> int ret;
> @@ -987,7 +986,13 @@ fwnode_create_software_node(const struct property_entry *properties,
>
> node->parent = p ? p->node : NULL;
>
> - return swnode_register(node, p, 1);
> + fwnode = swnode_register(node, p, 1);
> + if (IS_ERR(fwnode)) {
> + property_entries_free(node->properties);
> + kfree(node);
> + }
> +
> + return fwnode;
> }
> EXPORT_SYMBOL_GPL(fwnode_create_software_node);
>
> --
> 2.30.2

thanks,

--
heikki