Re: [PATCH net-next] net: dsa: Remove indirect function call for flow dissection

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Thu,  2 Jan 2020 15:36:53 -0800

We only need "static" information to be given for DSA flow dissection,
so replace the expensive call to .flow_dissect() with an integer giving
us the offset into the packet array of bytes that we must de-reference
to obtain the protocol number. The overhead was alreayd available from
the dsa_device_ops structure so use that directly.

The presence of a flow_dissect callback used to indicate that the DSA
tagger supported returning that information,we now encode this with a
proto_off value of DSA_PROTO_OFF_UNPSEC if the tagger does not support
providing that information yet.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
Changes since RFC:

- use a constant instead of the "magic" -1
- update all tag drivers and build test correctly

At the very least the typos need to be fixed, so marking this changes
requested in patchwork just FYI...