[PATCH net-next 3/8] devlink: Prepare code to fill multiple port function attributes

[Parav Pandit <parav@nvidia.com>]

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>
---
 net/core/devlink.c | 53 +++++++++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index e93730065c57..d152489e48da 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -570,6 +570,31 @@ static int devlink_nl_port_attrs_put(struct sk_buff *msg,
 	return 0;
 }
 
+static int
+devlink_port_function_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)
@@ -577,36 +602,16 @@ devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *por
 	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_function_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);
-- 
2.26.2