4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xu Yang <xu.yang_2@xxxxxxx>
commit b787a3e781759026a6212736ef8e52cf83d1821a upstream.
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>
Link: https://lore.kernel.org/r/20240129093739.2371530-2-xu.yang_2@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/roles/class.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -19,6 +19,7 @@ struct usb_role_switch {
struct device dev;
struct mutex lock; /* device lock*/
enum usb_role role;
+ bool registered;
/* From descriptor */
struct device *usb2_port;
@@ -45,6 +46,9 @@ int usb_role_switch_set_role(struct usb_
if (IS_ERR_OR_NULL(sw))
return 0;
+ if (!sw->registered)
+ return -EOPNOTSUPP;
+
mutex_lock(&sw->lock);
ret = sw->set(sw->dev.parent, role);
@@ -68,7 +72,7 @@ enum usb_role usb_role_switch_get_role(s
{
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);
@@ -276,6 +280,8 @@ usb_role_switch_register(struct device *
return ERR_PTR(ret);
}
+ sw->registered = true;
+
/* TODO: Symlinks for the host port and the device controller. */
return sw;
@@ -290,8 +296,10 @@ EXPORT_SYMBOL_GPL(usb_role_switch_regist
*/
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);
