[PATCH v3 1/2] vhost: destroy device when all vqs are inactive

[Kangjie Xu <kangjie.xu@linux.alibaba.com>]

We change the behavior of vhost_user_get_vring_base(). Previosly,
destroying a virtqueue will cause the whole device to be destroyed.
The behavior is not specified in the vhost-user protocol.

Thus, we refactor this part. The device will be destroyed only when
all virtqueues in the device are going to be destroyed.

This helps us to simplify the implementation when resetting a virtqueue.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 lib/vhost/vhost_user.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 4ad28bac45..a9f0709f94 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2088,10 +2088,16 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 {
 	struct virtio_net *dev = *pdev;
 	struct vhost_virtqueue *vq = dev->virtqueue[ctx->msg.payload.state.index];
+	uint32_t i, num_live_vring = 0;
 	uint64_t val;
 
-	/* We have to stop the queue (virtio) if it is running. */
-	vhost_destroy_device_notify(dev);
+	/* Stop the device when vq is the last active queue */
+	for (i = 0; i < dev->nr_vring; i++)
+		if (dev->virtqueue[i]->access_ok)
+			num_live_vring++;
+
+	if (num_live_vring == 1 && vq->access_ok)
+		vhost_destroy_device_notify(dev);
 
 	dev->flags &= ~VIRTIO_DEV_READY;
 	dev->flags &= ~VIRTIO_DEV_VDPA_CONFIGURED;
-- 
2.32.0