Vladimir Oltean 276d37eb44 net: mscc: ocelot: fix tagged VLAN refusal while under a VLAN-unaware bridge
Currently the following set of commands fails:

$ ip link add br0 type bridge # vlan_filtering 0
$ ip link set swp0 master br0
$ bridge vlan
port              vlan-id
swp0              1 PVID Egress Untagged
$ bridge vlan add dev swp0 vid 10
Error: mscc_ocelot_switch_lib: Port with more than one egress-untagged VLAN cannot have egress-tagged VLANs.

Dumping ocelot->vlans, one can see that the 2 egress-untagged VLANs on swp0 are
vid 1 (the bridge PVID) and vid 4094, a PVID used privately by the driver for
VLAN-unaware bridging. So this is why bridge vid 10 is refused, despite
'bridge vlan' showing a single egress untagged VLAN.

As mentioned in the comment added, having this private VLAN does not impose
restrictions to the hardware configuration, yet it is a bookkeeping problem.

There are 2 possible solutions.

One is to make the functions that operate on VLAN-unaware pvids:
- ocelot_add_vlan_unaware_pvid()
- ocelot_del_vlan_unaware_pvid()
- ocelot_port_setup_dsa_8021q_cpu()
- ocelot_port_teardown_dsa_8021q_cpu()
call something different than ocelot_vlan_member_(add|del)(), the latter being
the real problem, because it allocates a struct ocelot_bridge_vlan *vlan which
it adds to ocelot->vlans. We don't really *need* the private VLANs in
ocelot->vlans, it's just that we have the extra convenience of having the
vlan->portmask cached in software (whereas without these structures, we'd have
to create a raw ocelot_vlant_rmw_mask() procedure which reads back the current
port mask from hardware).

The other solution is to filter out the private VLANs from
ocelot_port_num_untagged_vlans(), since they aren't what callers care about.
We only need to do this to the mentioned function and not to
ocelot_port_num_tagged_vlans(), because private VLANs are never egress-tagged.

Nothing else seems to be broken in either solution, but the first one requires
more rework which will conflict with the net-next change  36a0bf4435 ("net:
mscc: ocelot: set up tag_8021q CPU ports independent of user port affinity"),
and I'd like to avoid that. So go with the other one.

Fixes: 54c3198460 ("net: mscc: ocelot: enforce FDB isolation when VLAN-unaware")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220927122042.1100231-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-28 19:03:28 -07:00
2022-09-18 13:44:14 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 3.3 GiB
Languages
C 97.5%
Assembly 1%
Shell 0.6%
Python 0.3%
Makefile 0.3%