Subject: Re: [net PATCH 1/2] ipv4: Restore fib_trie_flush_external function and fix call ordering

From: "Duyck, Alexander H" <[email-masked]>
Date: Tue, 15 Nov 2016 20:29:09 +0000

On Tue, 2016-11-15 at 20:51 +0100, Jiri Pirko wrote:
> Tue, Nov 15, 2016 at 11:46:06AM CET, [email-masked] wrote:
> > 
> > The patch that removed the FIB offload infrastructure was a bit too
> > aggressive and also removed code needed to clean up us splitting the table
> > if additional rules were added.  Specifically the function
> > fib_trie_flush_external was called at the end of a new rule being added to
> > flush the foreign trie entries from the main trie.
> > 
> > I updated the code so that we only call fib_trie_flush_external on the main
> > table so that we flush the entries for local from main.  This way we don't
> > call it for every rule change which is what was happening previously.
> 
> Well, the function was introduced by:
> 
> commit 104616e74e0b464d449fdd2ee2f547d2fad71610
> Author: Scott Feldman <[email-masked]>
> Date:   Thu Mar 5 21:21:16 2015 -0800
> 
>     switchdev: don't support custom ip rules, for now
>     
>     Keep switchdev FIB offload model simple for now and don't allow custom ip
>     rules.
> 
> Why this was not needed before? What changed in between:
> 104616e74e0b464d449fdd2ee2f547d2fad71610 ("switchdev: don't support custom ip rules, for now")
> and
> 347e3b28c1ba2 ("switchdev: remove FIB offload infrastructure")

We collapsed the two tables into one in commit 0ddcf43d5d4a ("ipv4: FIB
Local/MAIN table collapse") which was submitted the next day.  Scott
and I were working on things at the same time and the
fib_table_flush_external function was something we had worked out that
would allow him to take care of his use case and me to take care of
cleaning up the tables after unmerging.

- Alex