selftests: forwarding: generalize bail_on_lldpad from mlxsw

mlxsw selftests often invoke a bail_on_lldpad() helper to make sure LLDPAD
is not running, to prevent conflicts between the QoS configuration applied
through TC or DCB command line tool, and the DCB configuration that LLDPAD
might apply. This helper might be useful to others. Move the function to
lib.sh, and parameterize to make reusable in other contexts.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mlxsw: Use shapers in QOS tests instead of forcing speed

QOS tests create congestion and verify the switch behavior. To create
congestion, they need to have more traffic than the port can handle, so
some of them force 1Gbps speed.

The tests assume that 1Gbps speed is supported, otherwise, they will fail.
Spectrum-4 ASIC will not support this speed in all ports, so to be able
to run QOS tests there, some adjustments are required. Use shapers to
limit the traffic instead of forcing speed. Note that for several ports,
the speed configuration is just for autoneg issues, so shaper is not needed
instead.

In tests that already use shapers, set the existing shaper to be a child of
a new TBF shaper which is added as a root qdisc and acts as a port shaper.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: devlink_lib: Split devlink_..._set() into save & set

Changing pool type from static to dynamic causes reinterpretation of
threshold values. They therefore need to be saved before pool type is
changed, then the pool type can be changed, and then the new values need
to be set up.

For that reason, set cannot subsume save, because it would be saving the
wrong thing, with possibly a nonsensical value, and restore would then fail
to restore the nonsensical value.

Thus extract a _save() from each of the relevant _set()'s. This way it is
possible to save everything up front, then to tweak it, and then restore in
the required order.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: forwarding: ETS: Use Qdisc counters

Currently the SW-datapath ETS selftests use "ip link" stats to obtain the
number of packets that went through a given band. mlxsw then uses ethtool
per-priority counters.

Instead, change both to use qdiscs. In SW datapath this is the obvious
choice, and now that mlxsw offloads FIFO, this should work on the offloaded
datapath as well. This has the effect of verifying that the FIFO offload
works.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: forwarding: sch_ets: Add test coverage for ETS Qdisc

This tests the newly-added ETS Qdisc. It runs two to three streams of
traffic, each with a different priority. ETS Qdisc is supposed to allocate
bandwidth according to the DRR algorithm and given weights. After running
the traffic for a while, counters are compared for each stream to check
that the expected ratio is in fact observed.

In order for the DRR process to kick in, a traffic bottleneck must exist in
the first place. In slow path, such bottleneck can be implemented by
wrapping the ETS Qdisc inside a TBF or other shaper. This might however
make the configuration unoffloadable. Instead, on HW datapath, the
bottleneck would be set up by lowering port speed and configuring shared
buffer suitably.

Therefore the test is structured as a core component that implements the
testing, with two wrapper scripts that implement the details of slow path
resp. fast path configuration.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>