netdev - Re: [PATCH v3 iwl-net 5/8] ice: toggle netif

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Date: Wed, 26 Jun 2024 14:21:39 +0200
From: Michal Kubiak <michal.kubiak@...el.com>
To: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
CC: <intel-wired-lan@...ts.osuosl.org>, <netdev@...r.kernel.org>,
	<anthony.l.nguyen@...el.com>, <magnus.karlsson@...el.com>,
	<larysa.zaremba@...el.com>, <jacob.e.keller@...el.com>, Shannon Nelson
	<shannon.nelson@....com>, Chandan Kumar Rout <chandanx.rout@...el.com>
Subject: Re: [PATCH v3 iwl-net 5/8] ice: toggle netif_carrier when setting up
 XSK pool

On Tue, Jun 04, 2024 at 03:21:52PM +0200, Maciej Fijalkowski wrote:
> This so we prevent Tx timeout issues. One of conditions checked on
> running in the background dev_watchdog() is netif_carrier_ok(), so let
> us turn it off when we disable the queues that belong to a q_vector
> where XSK pool is being configured.
> 
> Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
> Reviewed-by: Shannon Nelson <shannon.nelson@....com>
> Tested-by: Chandan Kumar Rout <chandanx.rout@...el.com> (A Contingent Worker at Intel)
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_xsk.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index 8ca7ff1a7e7f..21df6888961b 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -180,6 +180,7 @@ static int ice_qp_dis(struct ice_vsi *vsi, u16 q_idx)
>  	}
>  
>  	synchronize_net();
> +	netif_carrier_off(vsi->netdev);
>  	netif_tx_stop_queue(netdev_get_tx_queue(vsi->netdev, q_idx));
>  
>  	ice_qvec_dis_irq(vsi, rx_ring, q_vector);
> @@ -249,6 +250,7 @@ static int ice_qp_ena(struct ice_vsi *vsi, u16 q_idx)
>  	ice_qvec_ena_irq(vsi, q_vector);
>  
>  	netif_tx_start_queue(netdev_get_tx_queue(vsi->netdev, q_idx));
> +	netif_carrier_on(vsi->netdev);

I would add checking the physical link state before calling
'netif_carrier_on()'. Please consider the scenario that the link is
going physically *down* during the XSk pool configuration.
In such a case we can wrongly set "carrier_on" uncoditionally.
Please take a look at the followng suggestion:

	ice_get_link_status(vsi->port_info, &link_up);
	if (link_up)
 		netif_carrier_on(vsi->netdev);

Thanks,
Michal