Re: [PATCH] virtio-vdpa: Fix unchecked call to NULL set_vq_affinity

[Michael S. Tsirkin]

On Fri, May 12, 2023 at 12:51:21PM +0000, Dragos Tatulea wrote:
> On Thu, 2023-05-04 at 14:51 -0400, Michael S. Tsirkin wrote:
> > On Thu, May 04, 2023 at 01:08:54PM -0400, Feng Liu wrote:
> > > 
> > > 
> > > On 2023-05-04 a.m.9:50, Dragos Tatulea wrote:
> > > > External email: Use caution opening links or attachments
> > > > 
> > > > 
> > > > The referenced patch calls set_vq_affinity without checking if the op is
> > > > valid. This patch adds the check.
> > > > 
> > > > Fixes: 3dad56823b53 ("virtio-vdpa: Support interrupt affinity spreading
> > > > mechanism")
> > > > Reviewed-by: Gal Pressman <gal@xxxxxxxxxx>
> > > > Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> > > > ---
> > > >   drivers/virtio/virtio_vdpa.c | 4 +++-
> > > >   1 file changed, 3 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> > > > index eb6aee8c06b2..989e2d7184ce 100644
> > > > --- a/drivers/virtio/virtio_vdpa.c
> > > > +++ b/drivers/virtio/virtio_vdpa.c
> > > > @@ -385,7 +385,9 @@ static int virtio_vdpa_find_vqs(struct virtio_device
> > > > *vdev, unsigned int nvqs,
> > > >                          err = PTR_ERR(vqs[i]);
> > > >                          goto err_setup_vq;
> > > >                  }
> > > > -               ops->set_vq_affinity(vdpa, i, &masks[i]);
> > > > +
> > > > +               if (ops->set_vq_affinity)
> > > > +                       ops->set_vq_affinity(vdpa, i, &masks[i]);
> > > if ops->set_vq_affinity is NULL, should give an error code to err, and
> > > return err
> > 
> > Given we ignore return code, hardly seems like a critical thing to do.
> > Is it really important? affinity is an optimization isn't it?
> > 
> > > > 
> set_vq_affinity is optional so it's not an error if the op is not implemented.
> 
> Is there anything else that needs to be done for this fix?
> 
> Thanks,
> Dragos
> 

no, it's queued already.