devlink: hold the instance lock in port_split / port_unsplit callbacks

Let the core take the devlink instance lock around port splitting
and remove the now redundant locking in the drivers.

Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -2025,7 +2025,6 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 			       struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
-	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port_mapping port_mapping;
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	enum mlxsw_reg_pmtdb_status status;
@@ -2063,7 +2062,6 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 
 	port_mapping = mlxsw_sp_port->mapping;
 
-	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2077,13 +2075,11 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to create split ports\n");
 		goto err_port_split_create;
 	}
-	devl_unlock(devlink);
 
 	return 0;
 
 err_port_split_create:
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
-	devl_unlock(devlink);
 	return err;
 }
 
@@ -2091,7 +2087,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 				 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
-	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	char pmtdb_pl[MLXSW_REG_PMTDB_LEN];
 	unsigned int count;
@@ -2123,7 +2118,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 		return err;
 	}
 
-	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2132,7 +2126,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 	}
 
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
-	devl_unlock(devlink);
 
 	return 0;
 }

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

@@ -70,29 +70,21 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	devl_lock(devlink);
-
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
 	rtnl_unlock();
 	if (ret)
-		goto out;
+		return ret;
 
-	if (eth_port.port_lanes % count) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (eth_port.port_lanes % count)
+		return -EINVAL;
 
 	/* Special case the 100G CXP -> 2x40G split */
 	lanes = eth_port.port_lanes / count;
 	if (eth_port.lanes == 10 && count == 2)
 		lanes = 8 / count;
 
-	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
-out:
-	devl_unlock(devlink);
-
-	return ret;
+	return nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 }
 
 static int
@@ -104,29 +96,21 @@ nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	devl_lock(devlink);
-
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
 	rtnl_unlock();
 	if (ret)
-		goto out;
+		return ret;
 
-	if (!eth_port.is_split) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!eth_port.is_split)
+		return -EINVAL;
 
 	/* Special case the 100G CXP -> 2x40G unsplit */
 	lanes = eth_port.port_lanes;
 	if (eth_port.port_lanes == 8)
 		lanes = 10;
 
-	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
-out:
-	devl_unlock(devlink);
-
-	return ret;
+	return nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 }
 
 static int

net/core/devlink.c

@@ -8672,14 +8672,12 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_split_doit,
 		.flags = GENL_ADMIN_PERM,
-		.internal_flags = DEVLINK_NL_FLAG_NO_LOCK,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_UNSPLIT,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_unsplit_doit,
 		.flags = GENL_ADMIN_PERM,
-		.internal_flags = DEVLINK_NL_FLAG_NO_LOCK,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_NEW,