4.19-stable review patch. If anyone has any objections, please let me know.
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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 @@ -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);