On Mon, Jan 29, 2024 at 05:37:39PM +0800, Xu Yang wrote:
> There is a possibility that usb_role_switch device is unregistered before
> the user put usb_role_switch. In this case, the user may still want to
> get/set_role() since the user can't sense the changes of usb_role_switch.
>
> This will add a flag to show if usb_role_switch is already registered and
> avoid unwanted behaviors.
>
> Fixes: fde0aa6c175a ("usb: common: Small class for USB role switches")
> cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> Changes in v2:
> - new patch during test patch 1
> - add registered flag
> Changes in v3:
> - add fix tag and stable list
> ---
> drivers/usb/roles/class.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index 2bad038fb9ad..70165dd86b5d 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -23,6 +23,7 @@ struct usb_role_switch {
> struct mutex lock; /* device lock*/
> struct module *module; /* the module this device depends on */
> enum usb_role role;
> + bool registered;
>
> /* From descriptor */
> struct device *usb2_port;
> @@ -49,6 +50,9 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)
> if (IS_ERR_OR_NULL(sw))
> return 0;
>
> + if (!sw->registered)
> + return -EOPNOTSUPP;
> +
> mutex_lock(&sw->lock);
>
> ret = sw->set(sw, role);
> @@ -74,7 +78,7 @@ enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
> {
> enum usb_role role;
>
> - if (IS_ERR_OR_NULL(sw))
> + if (IS_ERR_OR_NULL(sw) || !sw->registered)
> return USB_ROLE_NONE;
>
> mutex_lock(&sw->lock);
> @@ -357,6 +361,8 @@ usb_role_switch_register(struct device *parent,
> return ERR_PTR(ret);
> }
>
> + sw->registered = true;
> +
> /* TODO: Symlinks for the host port and the device controller. */
>
> return sw;
> @@ -371,8 +377,10 @@ EXPORT_SYMBOL_GPL(usb_role_switch_register);
> */
> void usb_role_switch_unregister(struct usb_role_switch *sw)
> {
> - if (!IS_ERR_OR_NULL(sw))
> + if (!IS_ERR_OR_NULL(sw)) {
> + sw->registered = false;
> device_unregister(&sw->dev);
> + }
> }
> EXPORT_SYMBOL_GPL(usb_role_switch_unregister);
>
> --
> 2.34.1
--
heikki
