Messages in this thread | | | From | "Rustad, Mark D" <> | Subject | Re: [PATCH] virtio_pci: support enabling VFs | Date | Wed, 30 May 2018 17:11:37 +0000 |
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On May 30, 2018, at 9:54 AM, Duyck, Alexander H <alexander.h.duyck@intel.com> wrote:
> 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@redhat.com> 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.
I am inclined to agree. In this case, the presence of #ifdefs I think would be clearer. As written, someone will want to get rid of the pointer only to create a build problem when SR-IOV is not configured.
-- Mark Rustad, Networking Division, Intel Corporation [unhandled content-type:application/pgp-signature] | |