net: hns: fix device reference leaks

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 2271150b upstream.

Make sure to drop the reference taken by class_find_device() in
hnae_get_handle() on errors and when later releasing the handle.

Fixes: 6fe6611f ("net: add Hisilicon Network Subsystem...")
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Cc: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/ethernet/hisilicon/hns/hnae.c

@@ -331,8 +331,10 @@ struct hnae_handle *hnae_get_handle(struct device *owner_dev,
 		return ERR_PTR(-ENODEV);
 
 	handle = dev->ops->get_handle(dev, port_id);
-	if (IS_ERR(handle))
+	if (IS_ERR(handle)) {
+		put_device(&dev->cls_dev);
 		return handle;
+	}
 
 	handle->dev = dev;
 	handle->owner_dev = owner_dev;
@@ -355,6 +357,8 @@ struct hnae_handle *hnae_get_handle(struct device *owner_dev,
 	for (j = i - 1; j >= 0; j--)
 		hnae_fini_queue(handle->qs[j]);
 
+	put_device(&dev->cls_dev);
+
 	return ERR_PTR(-ENOMEM);
 }
 EXPORT_SYMBOL(hnae_get_handle);
@@ -376,6 +380,8 @@ void hnae_put_handle(struct hnae_handle *h)
 		dev->ops->put_handle(h);
 
 	module_put(dev->owner);
+
+	put_device(&dev->cls_dev);
 }
 EXPORT_SYMBOL(hnae_put_handle);