devlink: Prepare code to fill multiple port function attributes

Prepare code to fill zero or more port function optional attributes.
Subsequent patch makes use of this to fill more port function
attributes.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Vu Pham <vuhuong@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

net/core/devlink.c

@@ -712,43 +712,49 @@ static int devlink_nl_port_attrs_put(struct sk_buff *msg,
 	return 0;
 }
 
+static int
+devlink_port_fn_hw_addr_fill(struct devlink *devlink, const struct devlink_ops *ops,
+			     struct devlink_port *port, struct sk_buff *msg,
+			     struct netlink_ext_ack *extack, bool *msg_updated)
+{
+	u8 hw_addr[MAX_ADDR_LEN];
+	int hw_addr_len;
+	int err;
+
+	if (!ops->port_function_hw_addr_get)
+		return 0;
+
+	err = ops->port_function_hw_addr_get(devlink, port, hw_addr, &hw_addr_len, extack);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+	err = nla_put(msg, DEVLINK_PORT_FUNCTION_ATTR_HW_ADDR, hw_addr_len, hw_addr);
+	if (err)
+		return err;
+	*msg_updated = true;
+	return 0;
+}
+
 static int
 devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *port,
 				   struct netlink_ext_ack *extack)
 {
 	struct devlink *devlink = port->devlink;
 	const struct devlink_ops *ops;
 	struct nlattr *function_attr;
-	bool empty_nest = true;
-	int err = 0;
+	bool msg_updated = false;
+	int err;
 
 	function_attr = nla_nest_start_noflag(msg, DEVLINK_ATTR_PORT_FUNCTION);
 	if (!function_attr)
 		return -EMSGSIZE;
 
 	ops = devlink->ops;
-	if (ops->port_function_hw_addr_get) {
-		int hw_addr_len;
-		u8 hw_addr[MAX_ADDR_LEN];
-
-		err = ops->port_function_hw_addr_get(devlink, port, hw_addr, &hw_addr_len, extack);
-		if (err == -EOPNOTSUPP) {
-			/* Port function attributes are optional for a port. If port doesn't
-			 * support function attribute, returning -EOPNOTSUPP is not an error.
-			 */
-			err = 0;
-			goto out;
-		} else if (err) {
-			goto out;
-		}
-		err = nla_put(msg, DEVLINK_PORT_FUNCTION_ATTR_HW_ADDR, hw_addr_len, hw_addr);
-		if (err)
-			goto out;
-		empty_nest = false;
-	}
-
-out:
-	if (err || empty_nest)
+	err = devlink_port_fn_hw_addr_fill(devlink, ops, port, msg,
+					   extack, &msg_updated);
+	if (err || !msg_updated)
 		nla_nest_cancel(msg, function_attr);
 	else
 		nla_nest_end(msg, function_attr);
@@ -986,7 +992,6 @@ devlink_port_function_hw_addr_set(struct devlink *devlink, struct devlink_port *
 	const struct devlink_ops *ops;
 	const u8 *hw_addr;
 	int hw_addr_len;
-	int err;
 
 	hw_addr = nla_data(attr);
 	hw_addr_len = nla_len(attr);
@@ -1011,12 +1016,7 @@ devlink_port_function_hw_addr_set(struct devlink *devlink, struct devlink_port *
 		return -EOPNOTSUPP;
 	}
 
-	err = ops->port_function_hw_addr_set(devlink, port, hw_addr, hw_addr_len, extack);
-	if (err)
-		return err;
-
-	devlink_port_notify(port, DEVLINK_CMD_PORT_NEW);
-	return 0;
+	return ops->port_function_hw_addr_set(devlink, port, hw_addr, hw_addr_len, extack);
 }
 
 static int
@@ -1037,6 +1037,8 @@ devlink_port_function_set(struct devlink *devlink, struct devlink_port *port,
 	if (attr)
 		err = devlink_port_function_hw_addr_set(devlink, port, attr, extack);
 
+	if (!err)
+		devlink_port_notify(port, DEVLINK_CMD_PORT_NEW);
 	return err;
 }