!360 [sync] PR-338: Fix virtio-gpu free issues

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/338 
 
This PR is to backport upstream fix for virtio-gpu free issues on probe failure

issues:
First appearance in stratovirt test as a guest：
issue number：I66GGJ
Corresponding Kernel Issue
issue number：I688N6 
 
Link:https://gitee.com/openeuler/kernel/pulls/360 

Reviewed-by: Kevin Zhu <zhukeqian1@huawei.com> 
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> 
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> 

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -122,11 +122,13 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
 
 	ret = drm_dev_register(dev, 0);
 	if (ret)
-		goto err_free;
+		goto err_deinit;
 
 	drm_fbdev_generic_setup(vdev->priv, 32);
 	return 0;
 
+err_deinit:
+	virtio_gpu_deinit(dev);
 err_free:
 	drm_dev_put(dev);
 	return ret;

drivers/gpu/drm/virtio/virtgpu_kms.c

@@ -240,6 +240,9 @@ void virtio_gpu_release(struct drm_device *dev)
 {
 	struct virtio_gpu_device *vgdev = dev->dev_private;
 
+	if (!vgdev)
+		return;
+
 	virtio_gpu_modeset_fini(vgdev);
 	virtio_gpu_free_vbufs(vgdev);
 	virtio_gpu_cleanup_cap_cache(vgdev);