From mboxrd@z Thu Jan  1 00:00:00 1970
From: Scott Feldman <sfeldma@gmail.com>
Subject: Re: [net-next PATCH v1 08/11] net: rocker: add get flow API operation
Date: Mon, 5 Jan 2015 23:40:05 -0800
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Cc: Thomas Graf <tgraf@suug.ch>,
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To: John Fastabend <john.fastabend@gmail.com>
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On Wed, Dec 31, 2014 at 11:48 AM, John Fastabend
<john.fastabend@gmail.com> wrote:
> Add operations to get flows. I wouldn't mind cleaning this code
> up a bit but my first attempt to do this used macros which shortered
> the code up but when I was done I decided it just made the code
> unreadable and unmaintainable.
>
> I might think about it a bit more but this implementation albeit
> a bit long and repeatative is easier to understand IMO.

Dang, you put a lot of work into this one.

Something doesn't feel right though.  In this case, rocker driver just
happened to have cached all the flow/group stuff in hash tables in
software, so you don't need to query thru to the device to extract the
if_flow info.  What doesn't feel right is all the work need in the
driver.  For each and every driver.  get_flows needs to go above
driver, somehow.

Seems the caller of if_flow already knows the flows pushed down with
add_flows/del_flows, and with the err handling can't mess it up.

Is one use-case for get_flows to recover from a fatal OS/driver crash,
and to rely on hardware to recover flow set?  In this rocker example,
that's not going to work because driver didn't get thru to device to
get_flows.  I think I'd like to know more about the use-cases of
get_flows.

-scott