[PATCH v9 16/32] virtio_ring: packed: introduce virtqueue_reinit_packed()

[Xuan Zhuo]

Introduce a function to initialize vq without allocating new ring,
desc_state, desc_extra.

Subsequent patches will call this function after reset vq to
reinitialize vq.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index c783eb272468..9a4f2db718bd 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1971,6 +1971,27 @@ static void vring_virtqueue_init_packed(struct vring_virtqueue *vq,
 	}
 }
 
+static void virtqueue_reinit_packed(struct vring_virtqueue *vq)
+{
+	struct virtio_device *vdev = vq->vq.vdev;
+	int size, i;
+
+	memset(vq->packed.vring.device, 0, vq->packed.event_size_in_bytes);
+	memset(vq->packed.vring.driver, 0, vq->packed.event_size_in_bytes);
+	memset(vq->packed.vring.desc, 0, vq->packed.ring_size_in_bytes);
+
+	size = sizeof(struct vring_desc_state_packed) * vq->packed.vring.num;
+	memset(vq->packed.desc_state, 0, size);
+
+	size = sizeof(struct vring_desc_extra) * vq->packed.vring.num;
+	memset(vq->packed.desc_extra, 0, size);
+
+	for (i = 0; i < vq->packed.vring.num - 1; i++)
+		vq->packed.desc_extra[i].next = i + 1;
+
+	vring_virtqueue_init_packed(vq, vdev);
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
-- 
2.31.0