netlink: add net device refcount tracker to struct ethnl_req_info

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ethtool/netlink.c

@@ -141,6 +141,7 @@ int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info,
 	}
 
 	req_info->dev = dev;
+	netdev_tracker_alloc(dev, &req_info->dev_tracker, GFP_KERNEL);
 	req_info->flags = flags;
 	return 0;
 }
@@ -399,7 +400,7 @@ static int ethnl_default_doit(struct sk_buff *skb, struct genl_info *info)
 		ops->cleanup_data(reply_data);
 
 	genlmsg_end(rskb, reply_payload);
-	dev_put(req_info->dev);
+	dev_put_track(req_info->dev, &req_info->dev_tracker);
 	kfree(reply_data);
 	kfree(req_info);
 	return genlmsg_reply(rskb, info);
@@ -411,7 +412,7 @@ static int ethnl_default_doit(struct sk_buff *skb, struct genl_info *info)
 	if (ops->cleanup_data)
 		ops->cleanup_data(reply_data);
 err_dev:
-	dev_put(req_info->dev);
+	dev_put_track(req_info->dev, &req_info->dev_tracker);
 	kfree(reply_data);
 	kfree(req_info);
 	return ret;
@@ -547,7 +548,7 @@ static int ethnl_default_start(struct netlink_callback *cb)
 		 * same parser as for non-dump (doit) requests is used, it
 		 * would take reference to the device if it finds one
 		 */
-		dev_put(req_info->dev);
+		dev_put_track(req_info->dev, &req_info->dev_tracker);
 		req_info->dev = NULL;
 	}
 	if (ret < 0)
@@ -624,6 +625,7 @@ static void ethnl_default_notify(struct net_device *dev, unsigned int cmd,
 	}
 
 	req_info->dev = dev;
+	netdev_tracker_alloc(dev, &req_info->dev_tracker, GFP_KERNEL);
 	req_info->flags |= ETHTOOL_FLAG_COMPACT_BITSETS;
 
 	ethnl_init_reply_data(reply_data, ops, dev);

net/ethtool/netlink.h

@@ -222,6 +222,7 @@ static inline unsigned int ethnl_reply_header_size(void)
 /**
  * struct ethnl_req_info - base type of request information for GET requests
  * @dev:   network device the request is for (may be null)
+ * @dev_tracker: refcount tracker for @dev reference
  * @flags: request flags common for all request types
  *
  * This is a common base for request specific structures holding data from
@@ -230,6 +231,7 @@ static inline unsigned int ethnl_reply_header_size(void)
  */
 struct ethnl_req_info {
 	struct net_device	*dev;
+	netdevice_tracker	dev_tracker;
 	u32			flags;
 };