[PATCH net-next v3 0/3] net: rss: Consider RSS not supported when key and indir sizes are 0

Hi,

This series follows what used to be an stmmac-only series to handle
devices that don't support RSS but still provice the associated ethtool
ops.

There are a few drivers out there that populate the RSS ethtool ops, but
don't always support RSS. stmmac and mvpp2 are such examples.

Following discussions with Jakub on V2, patch 1 makes so that returning
a 0-length key and a 0-size indirection table means "we don't do RSS".

Patch 2 introduces a helper to check for RSS support in stmmac, and
Patch 3 uses it. Patch 3 has been reworked so I haven't applied the
review tags, sorry about that Joe, Lorenzo and Nicolai :( I've drop the
-EOPNOTSUPP return from the rxfh ops as we return 0 on the sizes.

V3:
 - Add patch 1,
 - No changes on patch 2
 - Removed the -EOPNOTSUPP returns on patch 3

V2:
https://lore.kernel.org/r/20260928145043.1228968-1-maxime.chevallier@bootlin.com (local)
 - target net-next
 - Add a dedicated helper, following Nicolai's review.

V1: https://lore.kernel.org/netdev/20260926093343.292181-1-maxime.chevallier@bootlin.com/#t (local)

Maxime Chevallier (3):
  net: rss: Require indir table size or hash key size to support RSS
  net: stmmac: Introduce a helper to check RSS support
  net: stmmac: Don't set or get RSS parameters when not supported

 drivers/net/ethernet/stmicro/stmmac/stmmac.h         | 5 +++++
 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 6 ++++++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c    | 4 ++--
 net/ethtool/ioctl.c                                  | 6 ++++++
 net/ethtool/rss.c                                    | 7 +++++--
 5 files changed, 24 insertions(+), 4 deletions(-)

-- 
2.55.0