+/*
+ * The caller must pass in a device that has the kref held and the refcount
+ * released. If the device is in cur_net and still registered then it is moved
+ * into net.
+ */
+static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net,
+ struct net *net)
+{
+ int ret2 = -EINVAL;
+ int ret;
+
+ mutex_lock(&device->unregistration_lock);
+
+ /*
+ * If a device not under ib_device_get() or the unregistration_lock
+ * the namespace can be changed, or it can be unregistered. Check
+ * again under the lock.
+ */
+ if (refcount_read(&device->refcount) == 0 ||
+ !net_eq(cur_net, read_pnet(&device->coredev.rdma_net))) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ kobject_uevent(&device->dev.kobj, KOBJ_REMOVE);
+ disable_device(device);
+
+ /*
+ * At this point no one can be using the device, so it is safe to
+ * change the namespace.
+ */
+ write_pnet(&device->coredev.rdma_net, net);
+
+ /*
+ * Currently rdma devices are system wide unique. So the device name
+ * is guaranteed free in the new namespace. Publish the new namespace
+ * at the sysfs level.
+ */
+ down_read(&devices_rwsem);
+ ret = device_rename(&device->dev, dev_name(&device->dev));
+ up_read(&devices_rwsem);
+ if (ret) {
+ dev_warn(&device->dev,
+ "%s: Couldn't rename device after namespace change\n",
+ __func__);
+ /* Try and put things back and re-enable the device */
+ write_pnet(&device->coredev.rdma_net, cur_net);
+ }
+
+ ret2 = enable_device_and_get(device);
+ if (ret2)
+ /*
+ * This shouldn't really happen, but if it does, let the user
+ * retry at later point. So don't disable the device.
+ */
+ dev_warn(&device->dev,
+ "%s: Couldn't re-enable device after namespace change\n",
+ __func__);
+ kobject_uevent(&device->dev.kobj, KOBJ_ADD);
+ ib_device_put(device);
+out:
+ mutex_unlock(&device->unregistration_lock);
+ if (ret)
+ return ret;
+ return ret2;
+}
+