vhost: get available vring entries

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Acked-by: Changchun Ouyang <changchun.ouyang@intel.com>
[Thomas: split patch]

diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index 0e9c473..73423dd 100644 (file)
--- a/lib/librte_vhost/rte_virtio_net.h
+++ b/lib/librte_vhost/rte_virtio_net.h
@@ -119,6 +119,12 @@ struct virtio_net_device_ops {
        void (* destroy_device) (volatile struct virtio_net *); /* Remove device. */
 };
 
+static inline uint16_t __attribute__((always_inline))
+rte_vring_available_entries(struct virtio_net *dev, uint16_t queue_id)
+{
+       struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
+       return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx_res;
+}
 
 /**
  * Function to convert guest physical addresses to vhost virtual addresses.