Merge branch 'gred-add-offload-support'

Jakub Kicinski says:

====================
gred: add offload support

This series adds support for GRED offload in the nfp driver.  So
far we have only supported the RED Qdisc offload, but we need a
way to differentiate traffic types e.g. based on DSCP marking.

It may seem like PRIO+RED is a good match for this job, however,
(a) we don't need strict priority behaviour of PRIO, and (b) PRIO
uses the legacy way of mapping ToS fields to bands, which is quite
awkward and limitting.

The less commonly used GRED Qdisc is a better much for the scenario,
it allows multiple sets of RED parameters and queue lengths to be
maintained with a single FIFO queue.  This is exactly how nfp offload
behaves.  We use a trivial u32 classifier to assign packets to virtual
queues.

There is also the minor advantage that GRED can't have its child
changed, therefore limitting ways in which the configuration of SW
path can diverge from HW offload.

Last patch of the series adds support for (G)RED in non-ECN mode,
where packets are dropped instead of marked.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>