RE: [PATCH iwl-net 04/10] ice: restore the default XPS map after a netdev TC change

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Petr Oros <poros@xxxxxxxxxx>
> Sent: Friday, October 2, 2026 3:08 PM
> To: netdev@xxxxxxxxxxxxxxx
> Cc: Oros, Petr <poros@xxxxxxxxxx>; Nguyen, Anthony L
> <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@xxxxxxxxx>; Andrew Lunn <andrew+netdev@xxxxxxx>;
> David S. Miller <davem@xxxxxxxxxxxxx>; Eric Dumazet
> <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni
> <pabeni@xxxxxxxxxx>; Lobakin, Aleksander
> <aleksander.lobakin@xxxxxxxxx>; Alexei Starovoitov <ast@xxxxxxxxxx>;
> Daniel Borkmann <daniel@xxxxxxxxxxxxx>; Jesper Dangaard Brouer
> <hawk@xxxxxxxxxx>; John Fastabend <john.fastabend@xxxxxxxxx>;
> Stanislav Fomichev <sdf@xxxxxxxxxxx>; Henry Tieman
> <henry.w.tieman@xxxxxxxxx>; Anirudh Venkataramanan
> <anirudh.venkataramanan@xxxxxxxxx>; Michal Swiatkowski
> <michal.swiatkowski@xxxxxxxxxxxxxxx>; Jesse Brandeburg
> <jbrandeb@xxxxxxxxxx>; Preethi Banala <preethi.banala@xxxxxxxxx>;
> Kiran Patil <kiran.patil@xxxxxxxxx>; Dan Nowlin
> <dan.nowlin@xxxxxxxxx>; Stephen Hemminger
> <stephen@xxxxxxxxxxxxxxxxxx>; intel-wired-lan@xxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; bpf@xxxxxxxxxxxxxxx
> Subject: [PATCH iwl-net 04/10] ice: restore the default XPS map after
> a netdev TC change
> 
> ice_cfg_xps_tx_ring() programs the default XPS map only once per ring,
> guarded by ICE_TX_XPS_INIT_DONE. netdev_reset_tc() and
> netdev_set_num_tc() drop all XPS maps of the device, but the bit is
> never cleared, so the default map is not programmed again.
> 
> Since commit 122045ca7704 ("ice: config netdev tc before setting
> queues
> number") ice_vsi_open() calls ice_vsi_cfg_netdev_tc() after the Tx
> queues have been configured, so the map is wiped right after it was
> written on every open and stays empty:
> 
>   # cat /sys/class/net/enp4s0f0np0/queues/tx-*/xps_cpus
>   0000
>   0000
>   ...
> 
> A DCB reconfiguration ends the same way through ice_vsi_cfg_tc().
> 
> Clear ICE_TX_XPS_INIT_DONE in ice_vsi_cfg_netdev_tc(), which resets
> the netdev TC state, and configure the netdev TCs in ice_vsi_open()
> before the Tx queues so the default map is applied after the reset,
> not before it.
> 
> i40e fixed the same stale bit in commit 82e0572b2302 ("i40e: Fix not
> setting default xps_cpus after reset").
> 
> Fixes: 122045ca7704 ("ice: config netdev tc before setting queues
> number")
> Assisted-by: LLM
> Signed-off-by: Petr Oros <poros@xxxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/ice/ice_lib.c  | 6 ++++++
> drivers/net/ethernet/intel/ice/ice_main.c | 6 +++---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c
> b/drivers/net/ethernet/intel/ice/ice_lib.c
> index 5e183314e0d792..416e2d6a6f1709 100644
> --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> @@ -3218,6 +3218,12 @@ void ice_vsi_cfg_netdev_tc(struct ice_vsi *vsi,
> u8 ena_tc)
>  	if (vsi->type == ICE_VSI_CHNL)
>  		return;
> 
> +	if (vsi->tx_rings)
> +		ice_for_each_txq(vsi, i)
> +			if (vsi->tx_rings[i])
> +				clear_bit(ICE_TX_XPS_INIT_DONE,
> +					  vsi->tx_rings[i]->xps_state);
> +
>  	if (!ena_tc) {
>  		netdev_reset_tc(netdev);
>  		return;
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c
> b/drivers/net/ethernet/intel/ice/ice_main.c
> index e62a8f544345a3..8a21f87eb6ca21 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -7559,6 +7559,9 @@ int ice_vsi_open(struct ice_vsi *vsi)
>  	if (err)
>  		goto err_setup_rx;
> 
> +	if (bitmap_empty(pf->txtime_txqs, pf->max_pf_txqs))
> +		ice_vsi_cfg_netdev_tc(vsi, vsi->tc_cfg.ena_tc);
> +
>  	err = ice_vsi_cfg_lan(vsi);
>  	if (err)
>  		goto err_stop_tx;
> @@ -7569,9 +7572,6 @@ int ice_vsi_open(struct ice_vsi *vsi)
>  	if (err)
>  		goto err_stop_tx;
> 
> -	if (bitmap_empty(pf->txtime_txqs, pf->max_pf_txqs))
> -		ice_vsi_cfg_netdev_tc(vsi, vsi->tc_cfg.ena_tc);
> -
>  	if (vsi->type == ICE_VSI_PF || vsi->type == ICE_VSI_SF) {
>  		/* Notify the stack of the actual queue counts. */
>  		err = netif_set_real_num_tx_queues(vsi->netdev, vsi-
> >num_txq);
> --
> 2.55.0

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>