virtio_ring: split: extract the logic of attach vring

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

virtqueue_vring_init_split() completes the initialization of other
variables of vring split. We can directly use
vq->split = *vring_split to complete attach.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-14-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_ring.c

@@ -957,6 +957,15 @@ static void virtqueue_vring_init_split(struct vring_virtqueue_split *vring_split
 	}
 }
 
+static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
+					 struct vring_virtqueue_split *vring_split)
+{
+	vq->split = *vring_split;
+
+	/* Put everything in free lists. */
+	vq->free_head = 0;
+}
+
 static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
 {
 	struct vring_desc_state_split *state;
@@ -1067,8 +1076,6 @@ static struct virtqueue *vring_create_virtqueue_split(
 		return NULL;
 	}
 
-	to_vvq(vq)->split.queue_dma_addr = vring_split.queue_dma_addr;
-	to_vvq(vq)->split.queue_size_in_bytes = vring_split.queue_size_in_bytes;
 	to_vvq(vq)->we_own_ring = true;
 
 	return vq;
@@ -2317,26 +2324,16 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	vq->split.queue_dma_addr = 0;
-	vq->split.queue_size_in_bytes = 0;
-
-	vq->split.vring = vring_split->vring;
-
 	err = vring_alloc_state_extra_split(vring_split);
 	if (err) {
 		kfree(vq);
 		return NULL;
 	}
 
-	/* Put everything in free lists. */
-	vq->free_head = 0;
-
-	vq->split.desc_state = vring_split->desc_state;
-	vq->split.desc_extra = vring_split->desc_extra;
-
 	virtqueue_vring_init_split(vring_split, vq);
 
 	virtqueue_init(vq, vring_split->vring.num);
+	virtqueue_vring_attach_split(vq, vring_split);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);