Merge branch 'add-tx-push-buf-len-param-to-ethtool'

Shay Agroskin says:

====================
Add tx push buf len param to ethtool

This patchset adds a new sub-configuration to ethtool get/set queue
params (ethtool -g) called 'tx-push-buf-len'.

This configuration specifies the maximum number of bytes of a
transmitted packet a driver can push directly to the underlying
device ('push' mode). The motivation for pushing some of the bytes to
the device has the advantages of

- Allowing a smart device to take fast actions based on the packet's
  header
- Reducing latency for small packets that can be copied completely into
  the device

This new param is practically similar to tx-copybreak value that can be
set using ethtool's tunable but conceptually serves a different purpose.
While tx-copybreak is used to reduce the overhead of DMA mapping and
makes no sense to use if less than the whole segment gets copied,
tx-push-buf-len allows to improve performance by analyzing the packet's
data (usually headers) before performing the DMA operation.

The configuration can be queried and set using the commands:

    $ ethtool -g [interface]

    # ethtool -G [interface] tx-push-buf-len [number of bytes]

This patchset also adds support for the new configuration in ENA driver
for which this parameter ensures efficient resources management on the
device side.
====================

Link: https://lore.kernel.org/r/20230323163610.1281468-1-shayagr@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>