vduse: Cleanup the old kernel states after reset failure

We should cleanup the old kernel states e.g. interrupt callback
no matter whether the userspace handle the reset correctly or not
since virtio-vdpa can't handle the reset failure now.

Otherwise, the old state might be used after reset which might
break something, e.g. the old interrupt callback might be triggered
by userspace after reset, which can break the virtio device driver.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20210906142158.181-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

drivers/vdpa/vdpa_user/vduse_dev.c

@@ -665,13 +665,11 @@ static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
 static int vduse_vdpa_reset(struct vdpa_device *vdpa)
 {
 	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
-
-	if (vduse_dev_set_status(dev, 0))
-		return -EIO;
+	int ret = vduse_dev_set_status(dev, 0);
 
 	vduse_dev_reset(dev);
 
-	return 0;
+	return ret;
 }
 
 static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)