Re: [PATCH v9 22/32] virtio_pci: queue_reset: extract the logic of active vq for modern pci

Xuan Zhuo
2022-04-14T06:25:02Z

On Tue, 12 Apr 2022 14:58:19 +0800, Jason Wang <jasowang@redhat.com> wrote:
>
> 在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> > Introduce vp_active_vq() to configure vring to backend after vq attach
> > vring. And configure vq vector if necessary.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> > drivers/virtio/virtio_pci_modern.c | 46 ++++++++++++++++++------------
> > 1 file changed, 28 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > index 86d301f272b8..49a4493732cf 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -176,6 +176,29 @@ static void vp_reset(struct virtio_device *vdev)
> > vp_disable_cbs(vdev);
> > }
> >
> > +static int vp_active_vq(struct virtqueue *vq, u16 msix_vec)
> > +{
> > + struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > + unsigned long index;
> > +
> > + index = vq->index;
> > +
> > + /* activate the queue */
> > + vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
> > + vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
> > + virtqueue_get_avail_addr(vq),
> > + virtqueue_get_used_addr(vq));
> > +
> > + if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
> > + msix_vec = vp_modern_queue_vector(mdev, index, msix_vec);
> > + if (msix_vec == VIRTIO_MSI_NO_VECTOR)
> > + return -EBUSY;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> > {
> > return vp_modern_config_vector(&vp_dev->mdev, vector);
> > @@ -220,32 +243,19 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> >
> > vq->num_max = num;
> >
> > - /* activate the queue */
> > - vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
> > - vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
> > - virtqueue_get_avail_addr(vq),
> > - virtqueue_get_used_addr(vq));
> > + err = vp_active_vq(vq, msix_vec);
> > + if (err)
> > + goto err;
> >
> > vq->priv = (void __force *)vp_modern_map_vq_notify(mdev, index, NULL);
> > if (!vq->priv) {
> > err = -ENOMEM;
> > - goto err_map_notify;
> > - }
> > -
> > - if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
> > - msix_vec = vp_modern_queue_vector(mdev, index, msix_vec);
> > - if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
> > - err = -EBUSY;
> > - goto err_assign_vector;
> > - }
> > + goto err;
> > }
> >
> > return vq;
> >
> > -err_assign_vector:
> > - if (!mdev->notify_base)
> > - pci_iounmap(mdev->pci_dev, (void __iomem __force *)vq->priv);
>
>
> We need keep this or anything I missed?

I think so, after modification, vp_modern_map_vq_notify is the last step before
returning vq. If it fails, then vq->priv is equal to NULL, so there is no need
to execute pci_iounmap.

Did I miss something?

Thanks.

>
> Thanks
>
>
> > -err_map_notify:
> > +err:
> > vring_del_virtqueue(vq);
> > return ERR_PTR(err);
> > }
>