Re: [PATCH v1] usb: roles: add lockdep class key to struct usb_role_switch

[Amit Sunil Dhamne]

On 8/13/24 9:49 PM, Greg KH wrote:
> On Tue, Aug 13, 2024 at 03:42:11PM -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>
> > ---
> >   drivers/usb/roles/class.c | 15 +++++++++++++++
> >   1 file changed, 15 insertions(+)
> >
> > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> > index d7aa913ceb8a..807a8f18ec20 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 +34,10 @@ struct usb_role_switch {
> >   	usb_role_switch_set_t set;
> >   	usb_role_switch_get_t get;
> >   	bool allow_userspace_control;
> > +
> > +#ifdef CONFIG_LOCKDEP
> > +	struct lock_class_key key;
> > +#endif
> Please do not put #ifdef lines in .c files, they are not needed for this
> change to work properly, right?
That's right. I will correct it in the next revision.
> checkpatch should have complained about this...

Unfortunately it didn't complain.

Thanks,

Amit

> thanks,
>
> greg k-h