On Wed, Jan 24, 2024 at 02:45:54PM +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.
>
> Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
>
> ---
> Changes in v2:
> - new patch during test patch 1
> - add registered flag
> ---
> 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;
What's to prevent this from changing right after you check it?
And why is this patch not cc: stable and have a fixes tag if it resolves
a real issue for people?
thanks,
greg k-h
