> From: Tian, Kevin <kevin.tian@xxxxxxxxx>
> Sent: Thursday, January 19, 2023 5:55 PM
>
> > From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> > Sent: Tuesday, January 17, 2023 9:50 PM
> >
> > @@ -17,7 +17,11 @@ struct vfio_device;
> > struct vfio_container;
> >
> > struct vfio_device_file {
> > + /* static fields, init per allocation */
> > struct vfio_device *device;
> > + bool single_open;
>
> I wonder whether the readability is better by renaming this
> to 'cdev', e.g.:
>
> /*
> * Device cdev path cannot support multiple device open since
> * it doesn't have a secure way for it. So a second device
> * open attempt should be failed if the caller is from a cdev
> * path or the device has already been opened by a cdev path.
> */
> if (device->open_count != 0 &&
> (df->cdev || device->single_open))
> return -EINVAL;
>
> /*
> * group path supports multiple device open, while cdev doesn't.
> * So use vfio_device_group_close() for !singel_open case.
> */
> if (!df->cdev)
> vfio_device_group_close(df);
>
> because from device file p.o.v we just want to differentiate cdev
> vs. group interface. With this change we even don't need the
> comment for the last condition check.
>
> it's fine to have device->single_open as it's kind of a status bit
> set in the cdev path to prevent more opens on this device.
Ok.
Regards,
Yi Liu
