[PATCH net 0/3] ENETC GSO fixes

[Vladimir Oltean <vladimir.oltean@nxp.com>]

Sashiko derailed me from "[PATCH v5 net 0/4] Fix short frame
transmission in enetc":
https://lore.kernel.org/netdev/20261021145314.1435049-1-vladimir.oltean@nxp.com/

which also touches the driver GSO code path, so I'm making a detour
to fix 3 unrelated issues there (which I could all reproduce using
LLM-produced programs).

The main highlight of this series is the introduction of
.ndo_features_check() for enetc, which runs for every transmitted skb.
Each patch makes its implementation more and more complex.

These patches all assume that at .ndo_features_check() time,
skb_shinfo(skb)->gso_segs is set properly. There might be issues there,
see commit 67b0cca9ba88 ("net: validate xmit skbs in generic_xdp_tx()")
which fixes one case which led to gso_segs reaching the driver while
being zero. For some reason it was merged to net-next though.

Running a bidirectional eno0 <-> swp0 forwarding of raw IPv4 64B packets
(no GRO or GSO) on LS1028A-QDS rather than some micro-benchmark,
I am not seeing a noticeable performance degradation. It is in the
noise margin.
Before: 7440 Kpps ingress, 586 Kpps egress
After: 7440 Kpps ingress, 588 Kpps egress

Vladimir Oltean (3):
  net: enetc: let core segment GSO super-skb when TSO would not fit the
    TX ring
  net: enetc: reserve VLAN extension BDs for software TSO
  net: enetc: let core segment GSO super-skb when headers exceed
    TSO_HEADER_SIZE

 drivers/net/ethernet/freescale/enetc/enetc.c  | 52 +++++++++++++++++--
 drivers/net/ethernet/freescale/enetc/enetc.h  |  3 ++
 .../net/ethernet/freescale/enetc/enetc4_pf.c  |  1 +
 .../net/ethernet/freescale/enetc/enetc_pf.c   |  1 +
 .../net/ethernet/freescale/enetc/enetc_vf.c   |  2 +
 5 files changed, 54 insertions(+), 5 deletions(-)

-- 
2.53.0