> From: Tian, Kevin <kevin.tian@xxxxxxxxx>
> Sent: Thursday, January 19, 2023 5:45 PM
>
> > From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> > Sent: Tuesday, January 17, 2023 9:50 PM
> > static int vfio_device_group_open(struct vfio_device_file *df)
> > {
> > struct vfio_device *device = df->device;
> > + u32 ioas_id;
> > + u32 *pt_id = NULL;
> > int ret;
> >
> > mutex_lock(&device->group->group_lock);
> > @@ -165,6 +167,14 @@ static int vfio_device_group_open(struct
> > vfio_device_file *df)
> > goto err_unlock_group;
> > }
> >
> > + if (device->group->iommufd) {
> > + ret = iommufd_vfio_compat_ioas_id(device->group-
> > >iommufd,
> > + &ioas_id);
> > + if (ret)
> > + goto err_unlock_group;
> > + pt_id = &ioas_id;
> > + }
> > +
> > mutex_lock(&device->dev_set->lock);
> > /*
> > * Here we pass the KVM pointer with the group under the lock. If
> > the
> > @@ -174,7 +184,7 @@ static int vfio_device_group_open(struct
> > vfio_device_file *df)
> > df->kvm = device->group->kvm;
> > df->iommufd = device->group->iommufd;
> >
> > - ret = vfio_device_open(df);
> > + ret = vfio_device_open(df, NULL, pt_id);
>
> having both ioas_id and pt_id in one function is a bit confusing.
>
> Does it read better with below?
>
> if (device->group->iommufd)
> ret = vfio_device_open(df, NULL, &ioas_id);
> else
> ret = vfio_device_open(df, NULL, NULL);
Yes. 😊
> > +/* @pt_id == NULL implies detach */
> > +int vfio_iommufd_attach(struct vfio_device *vdev, u32 *pt_id)
> > +{
> > + lockdep_assert_held(&vdev->dev_set->lock);
> > +
> > + return vdev->ops->attach_ioas(vdev, pt_id);
> > +}
>
> what benefit does this one-line wrapper give actually?
>
> especially pt_id==NULL is checked in the callback instead of in this
> wrapper.
Yep, will just open code in the caller.
Regards,
Yi Liu
