Subject: Re: [PATCH net] ice: Clear default forwarding VSI during VSI release

From: Maciej Fijalkowski <[email-masked]>
Date: Thu, 24 Mar 2022 12:10:51 +0100

On Wed, Mar 23, 2022 at 07:19:55PM +0100, Marcin Szycik wrote:
> 
> 
> On 23-Mar-22 18:54, Ivan Vecera wrote:
> > On Wed, 23 Mar 2022 18:39:11 +0100
> > Marcin Szycik <[email-masked]> wrote:
> > 
> >> On 22-Mar-22 15:25, Ivan Vecera wrote:
> >>> VSI is set as default forwarding one when promisc mode is set for
> >>> PF interface, when PF is switched to switchdev mode or when VF
> >>> driver asks to enable allmulticast or promisc mode for the VF
> >>> interface (when vf-true-promisc-support priv flag is off).
> >>> The third case is buggy because in that case VSI associated with
> >>> VF remains as default one after VF removal.
> >>>
> >>> Reproducer:
> >>> 1. Create VF
> >>>    echo 1 > sys/class/net/ens7f0/device/sriov_numvfs
> >>> 2. Enable allmulticast or promisc mode on VF
> >>>    ip link set ens7f0v0 allmulticast on
> >>>    ip link set ens7f0v0 promisc on
> >>> 3. Delete VF
> >>>    echo 0 > sys/class/net/ens7f0/device/sriov_numvfs
> >>> 4. Try to enable promisc mode on PF
> >>>    ip link set ens7f0 promisc on
> >>>
> >>> Although it looks that promisc mode on PF is enabled the opposite
> >>> is true because ice_vsi_sync_fltr() responsible for IFF_PROMISC
> >>> handling first checks if any other VSI is set as default forwarding
> >>> one and if so the function does not do anything. At this point
> >>> it is not possible to enable promisc mode on PF without re-probe
> >>> device.
> >>>
> >>> To resolve the issue this patch clear default forwarding VSI

tiny nit:
s/clear/clears

Also it's more welcome to use imperative mood.

> >>> during ice_vsi_release() when the VSI to be released is the default
> >>> one.
> >>>
> >>> Fixes: 01b5e89aab49 ("ice: Add VF promiscuous support")
> >>> Signed-off-by: Ivan Vecera <[email-masked]>
> >>> ---
> >>>  drivers/net/ethernet/intel/ice/ice_lib.c | 2 ++
> >>>  1 file changed, 2 insertions(+)
> >>>
> >>> diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
> >>> index 53256aca27c7..20d755822d43 100644
> >>> --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> >>> +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> >>> @@ -3147,6 +3147,8 @@ int ice_vsi_release(struct ice_vsi *vsi)
> >>>  		}
> >>>  	}
> >>>  
> >>> +	if (ice_is_vsi_dflt_vsi(pf->first_sw, vsi))
> >>> +		ice_clear_dflt_vsi(pf->first_sw);  
> >>
> >> It would probably be good to check `ice_clear_dflt_vsi` return code.
> > 
> > Check and report potential warning when error occurs? because we are in ice_vsi_release() so
> > any rollback does not make sense.

I believe that comment wouldn't hurt that it's ok to ignore the retval,
but then again i'm fine with what it is currently :)

Reviewed-by: Maciej Fijalkowski <[email-masked]>

> 
> Right. ice_clear_dflt_vsi already reports errors so it should be good as is.
> LGTM, thanks!
> 
> > 
> > Ivan
> >