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

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Message-ID: <ZnwdMw1TgvFG1Quc@boxer>
Date: Wed, 26 Jun 2024 15:52:51 +0200
From: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To: Michal Kubiak <michal.kubiak@...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 Wed, Jun 26, 2024 at 02:21:39PM +0200, Michal Kubiak wrote:
> 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);

Will include this in v4. Worth mentioning that it is safe to do so as
there is always a service task that will turn carrier on for us.

> 
> Thanks,
> Michal