[PATCH 5.4 62/84] usb: roles: dont get/set_role() when usb_role_switch is unregistered

Greg Kroah-Hartman
2024-02-27T14:24:25Z

From: Xu Yang <xu.yang_2@nxp.com>

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@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>
---
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
@@ -20,6 +20,7 @@ struct usb_role_switch {
struct device dev;
struct mutex lock; /* device lock*/
enum usb_role role;
+ bool registered;

/* From descriptor */
struct device *usb2_port;
@@ -46,6 +47,9 @@ 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);
@@ -69,7 +73,7 @@ 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);
@@ -319,6 +323,8 @@ 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;
@@ -333,8 +339,10 @@ 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);