[PATCH v10 21/41] virtio_ring: packed: extract the logic of vring init

[Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>]

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

This function completes the variable initialization of packed vring. It
together with the logic of atatch constitutes the initialization of
vring.

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 drivers/virtio/virtio_ring.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index c4a9d6827cf8..8d7c07494f04 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1922,6 +1922,22 @@ static void virtqueue_vring_attach_packed(struct vring_virtqueue *vq,
 	vq->packed.desc_extra = vring->desc_extra;
 }
 
+static void virtqueue_vring_init_packed(struct vring_virtqueue *vq)
+{
+	vq->packed.next_avail_idx = 0;
+	vq->packed.avail_wrap_counter = 1;
+	vq->packed.used_wrap_counter = 1;
+	vq->packed.event_flags_shadow = 0;
+	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
+
+	/* No callback?  Tell other side not to bother us. */
+	if (!vq->vq.callback) {
+		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
+		vq->packed.vring.driver->flags =
+			cpu_to_le16(vq->packed.event_flags_shadow);
+	}
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1958,25 +1974,13 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
 		!context;
 
-	vq->packed.next_avail_idx = 0;
-	vq->packed.avail_wrap_counter = 1;
-	vq->packed.used_wrap_counter = 1;
-	vq->packed.event_flags_shadow = 0;
-	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
-
 	err = vring_alloc_state_extra_packed(&vring);
 	if (err)
 		goto err_state_extra;
 
 	virtqueue_init(vq, num);
 	virtqueue_vring_attach_packed(vq, &vring);
-
-	/* No callback?  Tell other side not to bother us. */
-	if (!callback) {
-		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
-		vq->packed.vring.driver->flags =
-			cpu_to_le16(vq->packed.event_flags_shadow);
-	}
+	virtqueue_vring_init_packed(vq);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);
-- 
2.31.0