On Tue, 13 Jun 2023 14:42:46 +0000
"Liu, Yi L" <yi.l.liu@xxxxxxxxx> wrote:
> > From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > Sent: Tuesday, June 13, 2023 10:40 PM
> >
> > On Tue, 13 Jun 2023 14:28:43 +0000
> > "Liu, Yi L" <yi.l.liu@xxxxxxxxx> wrote:
> >
> > > > From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > > > Sent: Tuesday, June 13, 2023 10:18 PM
> > >
> > > > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> > > > > > > index 83cc5dc28b7a..e80a8ac86e46 100644
> > > > > > > --- a/include/linux/vfio.h
> > > > > > > +++ b/include/linux/vfio.h
> > > > > > > @@ -66,6 +66,7 @@ struct vfio_device {
> > > > > > > struct iommufd_device *iommufd_device;
> > > > > > > bool iommufd_attached;
> > > > > > > #endif
> > > > > > > + bool cdev_opened:1;
> > > > > >
> > > > > > Perhaps a more strongly defined data type here as well and roll
> > > > > > iommufd_attached into the same bit field scheme.
> > > > >
> > > > > Ok, then needs to make iommufd_attached always defined.
> > > >
> > > > That does not follow. Thanks,
> > >
> > > Well, I meant the iommufd_attached now is defined only when
> > > CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs
> > > to change this.
> >
> > Understood, but I don't think it's true. If defined we use one more
> > bit of the bit field, which is a consideration when we approach filling
> > it, but we're not using bit-shift operations to address these bits, so
> > why does it matter if one has compiler conditional usage? Thanks,
>
> Aha, I see. So you are suggesting something like the below. Is it?
>
> #if IS_ENABLED(CONFIG_IOMMUFD)
> struct iommufd_device *iommufd_device;
> u8 iommufd_attached:1;
> #endif
> u8 cdev_opened:1;
Precisely. Thanks,
Alex
