In other words, this patch set makes MAB work and breaks everything
else.
I'm willing to investigate exactly what is it that breaks the other
selftest, but not today. It may be related to the "RTNETLINK answers:
File exists"
messages, which themselves come from the commands
| bridge fdb add 00:01:02:03:04:01 dev lan2 master static
If I were to randomly guess at almost 4AM in the morning, it has to do
with
"bridge fdb add" rather than the "bridge fdb replace" that's used for
the MAB selftest. The fact I pointed out a few revisions ago, that MAB
needs to be opt-in, is now coming back to bite us. Since it's not
opt-in, the mv88e6xxx driver always creates locked FDB entries, and
when
we try to "bridge fdb add", the kernel says "hey, the FDB entry is
already there!". Is that it?
Yes, that sounds like a reasonable explanation, as it adds 'ext learned,
offloaded' entries. If you try and replace the 'add' with 'replace' in
those tests, does it work?
As for how to opt into MAB. Hmm. MAB seems to be essentially CPU
assisted learning, which creates locked FDB entries. I wonder whether
we
should reconsider the position that address learning makes no sense on
locked ports, and say that "+locked -learning" means no MAB, and
"+locked +learning" means MAB? This would make a bunch of things more
natural to handle in the kernel, and would also give us the opt-in we
need.
I have done the one and then the other. We need to have some final
decision on this point. And remember that this gave rise to an extra
patch to fix link-local learning if learning is turned on on a locked
port, which resulted in the decision to allways have learning off on
locked ports.
Side note, the VTU and ATU member violation printks annoy me so badly.
They aren't stating something super useful and they're a DoS attack
vector in itself, even if they're rate limited. I wonder whether we
could just turn the prints into a set of ethtool counters and call it a
day?
Sounds like a good idea to me. :-)
