virtio_ring: packed: extract the logic of attach vring

Separate the logic of attach vring, the subsequent patch will call it
separately.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-22-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_ring.c

@@ -1948,6 +1948,15 @@ static void virtqueue_vring_init_packed(struct vring_virtqueue_packed *vring_pac
 	}
 }
 
+static void virtqueue_vring_attach_packed(struct vring_virtqueue *vq,
+					  struct vring_virtqueue_packed *vring_packed)
+{
+	vq->packed = *vring_packed;
+
+	/* Put everything in free lists. */
+	vq->free_head = 0;
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1993,28 +2002,14 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	vq->packed.ring_dma_addr = vring_packed.ring_dma_addr;
-	vq->packed.driver_event_dma_addr = vring_packed.driver_event_dma_addr;
-	vq->packed.device_event_dma_addr = vring_packed.device_event_dma_addr;
-
-	vq->packed.ring_size_in_bytes = vring_packed.ring_size_in_bytes;
-	vq->packed.event_size_in_bytes = vring_packed.event_size_in_bytes;
-
-	vq->packed.vring = vring_packed.vring;
-
 	err = vring_alloc_state_extra_packed(&vring_packed);
 	if (err)
 		goto err_state_extra;
 
-	/* Put everything in free lists. */
-	vq->free_head = 0;
-
-	vq->packed.desc_state = vring_packed.desc_state;
-	vq->packed.desc_extra = vring_packed.desc_extra;
-
 	virtqueue_vring_init_packed(&vring_packed, !!callback);
 
 	virtqueue_init(vq, num);
+	virtqueue_vring_attach_packed(vq, &vring_packed);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);