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From:   Jason Wang <jasowang@redhat.com>
Date:   Wed, 12 Jan 2022 15:52:52 +0800
Message-ID: <CACGkMEs6u7o4pX4ahvnfPByt1BrSfmaFfEKm5pQJsjjH+XHYxw@mail.gmail.com>
Subject: Re: [PATCH] virtio_vdpa: Support surprise removal of virtio vdpa device
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     =?UTF-8?B?5p2O5Lic5Y2H?= <lidongsheng@dayudpu.com>,
        virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Wed, Jan 12, 2022 at 2:30 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Wed, Jan 12, 2022 at 10:23:07AM +0800, Jason Wang wrote:
> > On Tue, Jan 11, 2022 at 7:52 PM Michael S. Tsirkin <mst@redhat.com> wro=
te:
> > >
> > > On Tue, Jan 11, 2022 at 11:36:42AM +0800, =E6=9D=8E=E4=B8=9C=E5=8D=87=
 wrote:
> > > > When virtio vdpa device removed, the abnormal damage of the device =
cannot be
> > > > perceived normally, which will cause problems similar to:
> > > >
> > > > 43bb40c5b926
> > >
> > >
> > > Should include the subject of the patch too.
> > >
> > > > Hence, add the ability to abort the command on surprise removal
> > > >
> > > > Signed-off-by: dongsheng li <lidongsheng@dayudpu.com>
> > >
> > > When removing gracefully,
> > > I am not sure we should break device unconditionally like this
> > > before giving drivers a chance to clean up.
> > > Should we just do it for surprise removal?
> >
> > That requires a new method to query whether it's a surprise removal.
> >
> > Thanks
>
> We can check pci_device_is_present like virtio does.

Though the PCI device is the main user, we are vdpa transport that is
unaware of the type of its parent.

So it looks to me we need a new method and PCI parent and do call this
function when needed.

Thanks

>
> > >
> > > > ---
> > > >  drivers/virtio/virtio_vdpa.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_v=
dpa.c
> > > > index 4a9ddb44b2a7..fd930409d190 100644
> > > > --- a/drivers/virtio/virtio_vdpa.c
> > > > +++ b/drivers/virtio/virtio_vdpa.c
> > > > @@ -374,6 +374,7 @@ static void virtio_vdpa_remove(struct vdpa_devi=
ce *vdpa)
> > > >  {
> > > >   struct virtio_vdpa_device *vd_dev =3D vdpa_get_drvdata(vdpa);
> > > >
> > > > + virtio_break_device(vd_dev->vdev);
> > > >   unregister_virtio_device(&vd_dev->vdev);
> > > >  }
> > > >
> > > > --
> > > > 2.17.1
> > >
>