On Wed, 2018-05-30 at 09:44 -0700, Rustad, Mark D wrote:
> On May 30, 2018, at 9:22 AM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> > > +static int virtio_pci_sriov_configure(struct pci_dev *pci_dev, int
> > > num_vfs)
> > > +{
> > > + struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
> > > + struct virtio_device *vdev = &vp_dev->vdev;
> > > + int (*sriov_configure)(struct pci_dev *pci_dev, int num_vfs);
> > > +
> > > + if (!(vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK))
> > > + return -EBUSY;
> > > +
> > > + if (!__virtio_test_bit(vdev, VIRTIO_F_SR_IOV))
> > > + return -EINVAL;
> > > +
> > > + sriov_configure = pci_sriov_configure_simple;
> > > + if (sriov_configure == NULL)
> > > + return -ENOENT;
> >
> > BTW what is all this trickery in aid of?
>
> When SR-IOV support is not compiled into the kernel,
> pci_sriov_configure_simple is #defined as NULL. This allows it to compile
> in that case, even though there is utterly no way for it to be called in
> that case. It is an alternative to #ifs in the code.
Why even have the call though? I would wrap all of this in an #ifdef
and strip it out since you couldn't support SR-IOV if it isn't present
in the kernel anyway.
