Re: [PATCH v18 net-next 0/2] octeontx2: mqprio bandwidth offload for NIX TX schedulers

[Jakub Kicinski]

On Tue, 29 Sep 2026 07:59:13 +0530 Ratheesh Kannoth wrote:
> This series adds hardware offload for channel-mode mqprio with
> TC_MQPRIO_SHAPER_BW_RATE on Marvell octeontx2/cn10k PF and VF RVU
> netdevices. Each non-QoS transmit queue is shaped by programming MDQ CIR/PIR
> on the NIX TX scheduler. When bandwidth offload is active, the driver
> allocates one SMQ per queue, parents every MDQ under TL4[0], and maps each
> traffic class min/max rate to the queue(s) in that class.
> 
> The NIX TX scheduler hierarchy cannot be reprogrammed live today, so
> mqprio add, replace, delete, and failed-replace rollback rebuild it by
> bouncing the netdev through ndo_stop()/ndo_open(). That intentionally
> drops in-flight traffic on each change. otx2_mqprio_restart_netdev() clears
> __LINK_STATE_START before ndo_stop() and does not call
> dev_deactivate()/dev_activate(); carrier and TX queues are restored after
> ndo_open() via the normal link-event path when the link is up. Cache the
> active rates and restore MDQ shapers from otx2_mqprio_up() during ndo_open();
> fail closed if restoration fails, leaving ndo_open() unsuccessful and the
> interface administratively down.
> 
> Track mqprio configuration in mq_offload_snap snapshots (TC layout and
> rates). On tc qdisc replace, stage the new configuration while keeping
> the previous snapshot for rollback: failed setup restores the old
> snapshot via netdev restart when the interface is running, successful
> graft is recorded through TC_ROOT_GRAFT, and teardown of the replaced
> qdisc instance commits the staged snapshot without tearing down the live
> offload.
> 
> Patch 1 converts PF/VF and representor flag access to atomic bitops.
> Patch 2 depends on it for safe OTX2_FLAG_INTF_DOWN and OTX2_FLAG_PORT_UP
> updates on asynchronous mbox paths and during the mqprio netdev bounce.
> 
> The driver rejects offload unless the interface is running and the device
> advertises CIR+PIR support. PF and VF RVU netdevices share the same TC
> offload path via ndo_setup_tc / otx2_open(); SDP representors are not
> supported. Per-TC rates are rejected when a traffic class spans more than
> one queue. Concurrent PFC, XDP, SDP rep, or HTB use is blocked, and ethtool
> channel count changes are blocked while mqprio bandwidth offload is active.

coccicheck

drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c:2182:7-74: WARNING avoid newline at end of message in NL_SET_ERR_MSG_MOD

Obviously please still wait for the AI feedback before sending v19
-- 
pw-bot: cr