netdev - Re: Netlink NLM_F_DUMP

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Date:   Wed, 22 Jun 2022 13:12:18 +0200
From:   Ismael Luceno <iluceno@...e.de>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Paolo Abeni <pabeni@...hat.com>,
        David Ahern <dsahern@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: Netlink NLM_F_DUMP_INTR flag lost

On Fri, 17 Jun 2022 15:01:10 +0200
Ismael Luceno <iluceno@...e.de> wrote:
> On Thu, 16 Jun 2022 17:16:12 -0700
> Jakub Kicinski <kuba@...nel.org> wrote:
<...>
> > That's iterating over protocols, AFAICT, we don't guarantee
> > consistency across protocols.  
> 
> That's reasonable, I was just wondering about it because it does seem
> reasonable that the flags affect only the packets describing the table
> whose dump got interrupted...

So, just for clarification:


Scenario 1:
- 64 KB packet is filled.
- protocol table shrinks
- Next iteration finds it's done
- next protocol clears the seq, so nothing is flaged
- ...
- NLMSG_DONE (not flagged)

Scenario 2:
- 64 KB packet is filled.
- protocol table shrinks
- Next iteration finds it's done
- NLMSG_DONE (flagged with NLM_F_DUMP_INTR)

So, in order to break as little as possible, I was thinking about
introducing a new packet iff it happens we have to signal INTR between
protocols.

Does that sound good?

-- 
Ismael Luceno
SUSE L3 Support