Re: [PATCH V3 1/3] vhost-vdpa: flush workers on suspend

[Steven Sistare]

On 5/20/2024 10:28 PM, Jason Wang wrote:
> On Mon, May 20, 2024 at 11:21 PM Steve Sistare
> <steven.sistare@xxxxxxxxxx> wrote:
> > Flush to guarantee no workers are running when suspend returns.
> >
> > Fixes: f345a0143b4d ("vhost-vdpa: uAPI to suspend the device")
> > Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
> > Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> > ---
> >   drivers/vhost/vdpa.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index ba52d128aeb7..189596caaec9 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -594,6 +594,7 @@ static long vhost_vdpa_suspend(struct vhost_vdpa *v)
> >          struct vdpa_device *vdpa = v->vdpa;
> >          const struct vdpa_config_ops *ops = vdpa->config;
> >          int ret;
> > +       struct vhost_dev *vdev = &v->vdev;
> >
> >          if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
> >                  return 0;
> > @@ -601,6 +602,8 @@ static long vhost_vdpa_suspend(struct vhost_vdpa *v)
> >          if (!ops->suspend)
> >                  return -EOPNOTSUPP;
> >
> > +       vhost_dev_flush(vdev);
>
> vhost-vDPA doesn't use workers, see:
>
>          vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
>                         vhost_vdpa_process_iotlb_msg);
>
> So I wonder if this is a must.

True, but I am adding this to be future proof.  I could instead log a warning
or an error message if vhost_vdpa_suspend is called and v->vdev.use_worker=true,
but IMO we should just fix it, given that the fix is trivial.

- Steve