On Thu, Aug 22, 2024 at 03:37:15PM -0700, Amit Sunil Dhamne wrote:
> There can be multiple role switch devices running on a platform. Given
> that lockdep is not capable of differentiating between locks of
> different instances, false positive warnings for circular locking are
> reported. To prevent this, register unique lockdep key for each of the
> individual instances.
>
> Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> Reviewed-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> v1->v2
> - Avoid usage of ifdefs.
> v2->v3
> - Removed redundancies.
> - Completed peer review and added reviewer signature.
> ---
> drivers/usb/roles/class.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index d7aa913ceb8a..7aca1ef7f44c 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -11,6 +11,7 @@
> #include <linux/usb/role.h>
> #include <linux/property.h>
> #include <linux/device.h>
> +#include <linux/lockdep.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> #include <linux/slab.h>
> @@ -33,6 +34,8 @@ struct usb_role_switch {
> usb_role_switch_set_t set;
> usb_role_switch_get_t get;
> bool allow_userspace_control;
> +
> + struct lock_class_key key;
> };
>
> #define to_role_switch(d) container_of(d, struct usb_role_switch, dev)
> @@ -396,6 +399,9 @@ usb_role_switch_register(struct device *parent,
>
> sw->registered = true;
>
> + lockdep_register_key(&sw->key);
> + lockdep_set_class(&sw->lock, &sw->key);
> +
> /* TODO: Symlinks for the host port and the device controller. */
>
> return sw;
> @@ -412,6 +418,9 @@ void usb_role_switch_unregister(struct usb_role_switch *sw)
> {
> if (IS_ERR_OR_NULL(sw))
> return;
> +
> + lockdep_unregister_key(&sw->key);
> +
> sw->registered = false;
> if (dev_fwnode(&sw->dev))
> component_del(&sw->dev, &connector_ops);
>
> base-commit: ca7df2c7bb5f83fe46aa9ce998b7352c6b28f3a1
> --
> 2.46.0.184.g6999bdac58-goog
--
heikki
