[PATCH 4.9 010/148] virtio: release virtio index when fail to device_register

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: weiping zhang <zwp10758@xxxxxxxxx>

commit e60ea67bb60459b95a50a156296041a13e0e380e upstream.

index can be reused by other virtio device.

Signed-off-by: weiping zhang <zhangweiping@xxxxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/virtio/virtio.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -323,6 +323,8 @@ int register_virtio_device(struct virtio
 	/* device_register() causes the bus infrastructure to look for a
 	 * matching driver. */
 	err = device_register(&dev->dev);
+	if (err)
+		ida_simple_remove(&virtio_index_ida, dev->index);
 out:
 	if (err)
 		add_status(dev, VIRTIO_CONFIG_S_FAILED);