Re: [PATCH net-next 0/4] netlink: add 'bitmap' attribute type and API

From: Jakub Kicinski
Date: Thu Jul 21 2022 - 14:13:49 EST


On Thu, 21 Jul 2022 17:59:46 +0200 Alexander Lobakin wrote:
> BTW, Ethtool bitsets provide similar functionality, but it operates
> with u32s (u64 is more convenient and optimal on most platforms) and
> Netlink bitmaps is a generic interface providing policies and data
> verification (Ethtool bitsets are declared simply as %NLA_BINARY),
> generic getters/setters etc.

Are you saying we don't need the other two features ethtool bitmaps
provide? Masking and compact vs named representations?

I think that straight up bitmap with a fixed word is awkward and leads
to too much boilerplate code. People will avoid using it. What about
implementing a bigint type instead? Needing more than 64b is extremely
rare, so in 99% of the cases the code outside of parsing can keep using
its u8/u16/u32.