Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio fixes from Michael Tsirkin:
"Fixes and cleanups:

- A couple of mlx5 fixes related to cvq

- A couple of reverts dropping useless code (code that used it got
reverted earlier)"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vdpa: mlx5: synchronize driver status with CVQ
vdpa: mlx5: prevent cvq work from hogging CPU
Revert "virtio_config: introduce a new .enable_cbs method"
Revert "virtio: use virtio_device_ready() in virtio_device_restore()"

drivers/vdpa/mlx5/net/mlx5_vnet.c

···
 	u32 cur_num_vqs;
 	struct notifier_block nb;
 	struct vdpa_callback config_cb;
+	struct mlx5_vdpa_wq_ent cvq_ent;
 };
 
 static void free_resources(struct mlx5_vdpa_net *ndev);
···
 	mvdev = wqent->mvdev;
 	ndev = to_mlx5_vdpa_ndev(mvdev);
 	cvq = &mvdev->cvq;
+
+	mutex_lock(&ndev->reslock);
+
+	if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
+		goto out;
+
 	if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)))
 		goto out;
 
···
 
 		if (vringh_need_notify_iotlb(&cvq->vring))
 			vringh_notify(&cvq->vring);
+
+		queue_work(mvdev->wq, &wqent->work);
+		break;
 	}
+
 out:
-	kfree(wqent);
+	mutex_unlock(&ndev->reslock);
 }
 
 static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
···
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	struct mlx5_vdpa_virtqueue *mvq;
-	struct mlx5_vdpa_wq_ent *wqent;
 
 	if (!is_index_valid(mvdev, idx))
 		return;
···
 		if (!mvdev->wq || !mvdev->cvq.ready)
 			return;
 
-		wqent = kzalloc(sizeof(*wqent), GFP_ATOMIC);
-		if (!wqent)
-			return;
-
-		wqent->mvdev = mvdev;
-		INIT_WORK(&wqent->work, mlx5_cvq_kick_handler);
-		queue_work(mvdev->wq, &wqent->work);
+		queue_work(mvdev->wq, &ndev->cvq_ent.work);
 		return;
 	}
 
···
 		goto err_mr;
 
 	if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
-		return 0;
+		goto err_mr;
 
 	restore_channels_info(ndev);
 	err = setup_driver(mvdev);
···
 	return err;
 }
 
+/* reslock must be held for this function */
 static int setup_driver(struct mlx5_vdpa_dev *mvdev)
 {
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	int err;
 
-	mutex_lock(&ndev->reslock);
+	WARN_ON(!mutex_is_locked(&ndev->reslock));
+
 	if (ndev->setup) {
 		mlx5_vdpa_warn(mvdev, "setup driver called for already setup driver\n");
 		err = 0;
···
 		goto err_fwd;
 	}
 	ndev->setup = true;
-	mutex_unlock(&ndev->reslock);
 
 	return 0;
 
···
 err_rqt:
 	teardown_virtqueues(ndev);
 out:
-	mutex_unlock(&ndev->reslock);
 	return err;
 }
 
+/* reslock must be held for this function */
 static void teardown_driver(struct mlx5_vdpa_net *ndev)
 {
-	mutex_lock(&ndev->reslock);
+
+	WARN_ON(!mutex_is_locked(&ndev->reslock));
+
 	if (!ndev->setup)
-		goto out;
+		return;
 
 	remove_fwd_to_tir(ndev);
 	destroy_tir(ndev);
 	destroy_rqt(ndev);
 	teardown_virtqueues(ndev);
 	ndev->setup = false;
-out:
-	mutex_unlock(&ndev->reslock);
 }
 
 static void clear_vqs_ready(struct mlx5_vdpa_net *ndev)
···
 
 	print_status(mvdev, status, true);
 
+	mutex_lock(&ndev->reslock);
+
 	if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) {
 		if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
 			err = setup_driver(mvdev);
···
 			}
 		} else {
 			mlx5_vdpa_warn(mvdev, "did not expect DRIVER_OK to be cleared\n");
-			return;
+			goto err_clear;
 		}
 	}
 
 	ndev->mvdev.status = status;
+	mutex_unlock(&ndev->reslock);
 	return;
 
 err_setup:
 	mlx5_vdpa_destroy_mr(&ndev->mvdev);
 	ndev->mvdev.status |= VIRTIO_CONFIG_S_FAILED;
+err_clear:
+	mutex_unlock(&ndev->reslock);
 }
 
 static int mlx5_vdpa_reset(struct vdpa_device *vdev)
···
 
 	print_status(mvdev, 0, true);
 	mlx5_vdpa_info(mvdev, "performing device reset\n");
+
+	mutex_lock(&ndev->reslock);
 	teardown_driver(ndev);
 	clear_vqs_ready(ndev);
 	mlx5_vdpa_destroy_mr(&ndev->mvdev);
···
 		if (mlx5_vdpa_create_mr(mvdev, NULL))
 			mlx5_vdpa_warn(mvdev, "create MR failed\n");
 	}
+	mutex_unlock(&ndev->reslock);
 
 	return 0;
 }
···
 static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	bool change_map;
 	int err;
+
+	mutex_lock(&ndev->reslock);
 
 	err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map);
 	if (err) {
 		mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
-		return err;
+		goto err;
 	}
 
 	if (change_map)
-		return mlx5_vdpa_change_map(mvdev, iotlb);
+		err = mlx5_vdpa_change_map(mvdev, iotlb);
 
-	return 0;
+err:
+	mutex_unlock(&ndev->reslock);
+	return err;
 }
 
 static void mlx5_vdpa_free(struct vdpa_device *vdev)
···
 	if (err)
 		goto err_mr;
 
+	ndev->cvq_ent.mvdev = mvdev;
+	INIT_WORK(&ndev->cvq_ent.work, mlx5_cvq_kick_handler);
 	mvdev->wq = create_singlethread_workqueue("mlx5_vdpa_wq");
 	if (!mvdev->wq) {
 		err = -ENOMEM;

drivers/virtio/virtio.c

···
 			goto err;
 	}
 
-	/* If restore didn't do it, mark device DRIVER_OK ourselves. */
-	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
-		virtio_device_ready(dev);
+	/* Finally, tell the device we're all set */
+	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
 
 	virtio_config_enable(dev);
 

include/linux/virtio_config.h

···
  *       any of @get/@set, @get_status/@set_status, or @get_features/
  *       @finalize_features are NOT safe to be called from an atomic
  *       context.
- * @enable_cbs: enable the callbacks
- *      vdev: the virtio_device
  * @get: read the value of a configuration field
  *	vdev: the virtio_device
  *	offset: the offset of the configuration field
···
  */
 typedef void vq_callback_t(struct virtqueue *);
 struct virtio_config_ops {
-	void (*enable_cbs)(struct virtio_device *vdev);
 	void (*get)(struct virtio_device *vdev, unsigned offset,
 		    void *buf, unsigned len);
 	void (*set)(struct virtio_device *vdev, unsigned offset,
···
 void virtio_device_ready(struct virtio_device *dev)
 {
 	unsigned status = dev->config->get_status(dev);
-
-	if (dev->config->enable_cbs)
-                  dev->config->enable_cbs(dev);
 
 	BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);