Re: [RFC net-next 1/4] doc/netlink: Add batch op definitions to netlink-raw schema

[Donald Hunter <donald.hunter@gmail.com>]

Jakub Kicinski <kuba@kernel.org> writes:

> On Sun, 25 Feb 2024 17:46:16 +0000 Donald Hunter wrote:
>> The nftables netlink families use batch operations for create update and
>> delete operations. Extend the netlink-raw schema so that operations can
>> be marked as batch ops. Add definitions of the begin-batch and end-batch
>> messages.
>> 
>> The begin/end messages themselves are defined as ordinary ops, but there
>> are new attributes that describe the op name and parameters for the
>> begin/end messages.
>> 
>> The section of yaml spec that defines the begin/end ops looks like this;
>> the newtable op is marked 'is-batch: true' so the message needs to be
>> wrapped with 'batch-begin(res-id: 10)' and batch-end(res-id: 10) messages:
>
> I'm not familiar with nftables nl. Can you explain what the batch ops
> are for and how they function?
>
> Begin / end makes it sound like some form of a transaction, is it?

Yes, it's handled as a transaction, containing multiple messages wrapped
in BATCH_BEGIN / BATCH_END in a single skb.

The transaction batching could be implemented without any schema changes
by just adding multi-message capability to ynl. Then it would be the
caller's responsibility to specify the right begin / end messages.