Re: [PATCH v3 1/9] usb: typec: Copy everything from struct typec_capability during registration

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Oct 08, 2019 at 02:13:42PM +0300, Heikki Krogerus wrote:
> Copying everything from struct typec_capability to struct
> typec_port during port registration. This will make sure
> that under no circumstances the driver can change the values
> in the struct typec_capability that the port uses.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/usb/typec/class.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 94a3eda62add..0bbf10c8ad58 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -52,6 +52,7 @@ struct typec_port {
>  	struct typec_switch		*sw;
>  	struct typec_mux		*mux;
>  
> +	const struct typec_capability	*orig_cap; /* to be removed */
>  	const struct typec_capability	*cap;
>  };
>  
> @@ -968,7 +969,7 @@ preferred_role_store(struct device *dev, struct device_attribute *attr,
>  			return -EINVAL;
>  	}
>  
> -	ret = port->cap->try_role(port->cap, role);
> +	ret = port->cap->try_role(port->orig_cap, role);
>  	if (ret)
>  		return ret;
>  
> @@ -1014,7 +1015,7 @@ static ssize_t data_role_store(struct device *dev,
>  		goto unlock_and_ret;
>  	}
>  
> -	ret = port->cap->dr_set(port->cap, ret);
> +	ret = port->cap->dr_set(port->orig_cap, ret);
>  	if (ret)
>  		goto unlock_and_ret;
>  
> @@ -1071,7 +1072,7 @@ static ssize_t power_role_store(struct device *dev,
>  		goto unlock_and_ret;
>  	}
>  
> -	ret = port->cap->pr_set(port->cap, ret);
> +	ret = port->cap->pr_set(port->orig_cap, ret);
>  	if (ret)
>  		goto unlock_and_ret;
>  
> @@ -1119,7 +1120,7 @@ port_type_store(struct device *dev, struct device_attribute *attr,
>  		goto unlock_and_ret;
>  	}
>  
> -	ret = port->cap->port_type_set(port->cap, type);
> +	ret = port->cap->port_type_set(port->orig_cap, type);
>  	if (ret)
>  		goto unlock_and_ret;
>  
> @@ -1184,7 +1185,7 @@ static ssize_t vconn_source_store(struct device *dev,
>  	if (ret)
>  		return ret;
>  
> -	ret = port->cap->vconn_set(port->cap, (enum typec_role)source);
> +	ret = port->cap->vconn_set(port->orig_cap, (enum typec_role)source);
>  	if (ret)
>  		return ret;
>  
> @@ -1278,6 +1279,7 @@ static void typec_release(struct device *dev)
>  	ida_destroy(&port->mode_ids);
>  	typec_switch_put(port->sw);
>  	typec_mux_put(port->mux);
> +	kfree(port->cap);
>  	kfree(port);
>  }
>  
> @@ -1579,9 +1581,10 @@ struct typec_port *typec_register_port(struct device *parent,
>  	mutex_init(&port->port_type_lock);
>  
>  	port->id = id;
> -	port->cap = cap;
> +	port->orig_cap = cap;
>  	port->port_type = cap->type;
>  	port->prefer_role = cap->prefer_role;
> +	port->cap = kmemdup(cap, sizeof(*cap), GFP_KERNEL);

I just realized ... unfortunately kmemdup() can return NULL.

>  
>  	device_initialize(&port->dev);
>  	port->dev.class = typec_class;
> -- 
> 2.23.0
>