RE: [PATCH v6 20/24] vfio: Add cdev for vfio_device

Liu, Yi L
2023-03-10T10:00:10Z

> From: Tian, Kevin <kevin.tian@intel.com>
> Sent: Friday, March 10, 2023 4:49 PM
>
> > From: Liu, Yi L <yi.l.liu@intel.com>
> > Sent: Wednesday, March 8, 2023 9:29 PM
> >
> > + /*
> > + * Placing it before vfio_device_put_registration() to prevent
> > + * new registration refcount increment by
> > VFIO_GROUP_GET_DEVICE_FD
> > + * during the unregister time.
> > + */
> > + vfio_device_group_unregister(device);
> > +
> > + /*
> > + * Balances vfio_device_add() in the register path. Placing it before
> > + * vfio_device_put_registration() to prevent new registration
> refcount
> > + * increment by the device cdev open during the unregister time.
> > + */
> > + vfio_device_del(device);
> > +
>
> What about below?
>
> /*
> * Cleanup to pair with the register path. Must be done
> * before vfio_device_put_registration () to avoid racing with
> * a new registration.
> */
> vfio_device_group_unregister(device);
> vfio_device_del(device);

new registration is bit confusing. Maybe "new registration refcount
increment by userspace".

Regards,
Yi Liu