[PATCH net-next] net/ncsi: Add generic netlink family

[David Miller]

From: Samuel Mendoza-Jonas <sam at mendozajonas.com>
Date: Fri, 23 Feb 2018 15:15:18 +1100

> + * @NCSI_CMD_SET_INTERFACE: set preferred package and channel combination.
> + *	Requires NCSI_ATTR_IFINDEX and the preferred NCSI_ATTR_PACKAGE_ID and
> + *	optionally the preferred NCSI_ATTR_CHANNEL_ID. If neither IDs are
> + *	specified the setting is cleared.

I think clearing the setting when the required attributes are missing
is dangerous behavior.

It is ambiguous whether the user intended the setting to be cleared,
or was in error and forgot to supply the attribute due to a bug.