usb: roles: don't get/set_role() when usb_role_switch is unregistered

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@vger.kernel.org
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240129093739.2371530-2-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 2bad038fb9ada3d9b2c1a050ffae6dcfb939f704..70165dd86b5de958ab4f5fe0d1573988977be425 100644 (file)
--- 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);