devlink: Add a new devlink port split ability attribute and pass to netlink

Add a new attribute that indicates the split ability of devlink port.

Drivers are expected to set it via devlink_port_attrs_set(), before
registering the port.
Signed-off-by: Danielle Ratson <danieller@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -2135,6 +2135,7 @@ static int __mlxsw_core_port_init(struct mlxsw_core *mlxsw_core, u8 local_port,
 
 	attrs.split = split;
 	attrs.lanes = lanes;
+	attrs.splittable = splittable;
 	attrs.flavour = flavour;
 	attrs.phys.port_number = port_number;
 	attrs.phys.split_subport_number = split_port_subnumber;

drivers/net/ethernet/netronome/nfp/nfp_devlink.c

@@ -367,6 +367,7 @@ int nfp_devlink_port_register(struct nfp_app *app, struct nfp_port *port)
 		return ret;
 
 	attrs.split = eth_port.is_split;
+	attrs.splittable = !attrs.split;
 	attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
 	attrs.phys.port_number = eth_port.label_port;
 	attrs.phys.split_subport_number = eth_port.label_subport;

include/net/devlink.h

@@ -68,11 +68,13 @@ struct devlink_port_pci_vf_attrs {
  * struct devlink_port_attrs - devlink port object
  * @flavour: flavour of the port
  * @split: indicates if this is split port
+ * @splittable: indicates if the port can be split.
  * @lanes: maximum number of lanes the port supports. 0 value is not passed to netlink.
  * @switch_id: if the port is part of switch, this is buffer with ID, otherwise this is NULL
  */
 struct devlink_port_attrs {
-	u8 split:1;
+	u8 split:1,
+	   splittable:1;
 	u32 lanes;
 	enum devlink_port_flavour flavour;
 	struct netdev_phys_item_id switch_id;

include/uapi/linux/devlink.h

@@ -456,6 +456,7 @@ enum devlink_attr {
 	DEVLINK_ATTR_INFO_BOARD_SERIAL_NUMBER,	/* string */
 
 	DEVLINK_ATTR_PORT_LANES,			/* u32 */
+	DEVLINK_ATTR_PORT_SPLITTABLE,			/* u8 */
 
 	/* add new attributes above here, update the policy in devlink.c */
 

net/core/devlink.c

@@ -534,6 +534,8 @@ static int devlink_nl_port_attrs_put(struct sk_buff *msg,
 		if (nla_put_u32(msg, DEVLINK_ATTR_PORT_LANES, attrs->lanes))
 			return -EMSGSIZE;
 	}
+	if (nla_put_u8(msg, DEVLINK_ATTR_PORT_SPLITTABLE, attrs->splittable))
+		return -EMSGSIZE;
 	if (nla_put_u16(msg, DEVLINK_ATTR_PORT_FLAVOUR, attrs->flavour))
 		return -EMSGSIZE;
 	switch (devlink_port->attrs.flavour) {
@@ -7547,6 +7549,7 @@ void devlink_port_attrs_set(struct devlink_port *devlink_port,
 	ret = __devlink_port_attrs_set(devlink_port, attrs->flavour);
 	if (ret)
 		return;
+	WARN_ON(attrs->splittable && attrs->split);
 }
 EXPORT_SYMBOL_GPL(devlink_port_attrs_set);