On Fri, Jun 17, 2022 at 06:57:41PM -0700, John Fastabend wrote:
> Maciej Fijalkowski wrote:
> > Add support for NETIF_F_LOOPBACK. This feature can be set via:
> > $ ethtool -K eth0 loopback <on|off>
> >
> > Feature can be useful for local data path tests.
> >
> > CC: Alexandr Lobakin <alexandr.lobakin@xxxxxxxxx>
> > Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> > ---
>
> Patch looks fine one question about that ice_set_features() function
> though.
>
> Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
>
> [...]
>
> > +/**
> > + * ice_set_loopback - turn on/off loopback mode on underlying PF
> > + * @vsi: ptr to VSI
> > + * @ena: flag to indicate the on/off setting
> > + */
> > +static int
> > +ice_set_loopback(struct ice_vsi *vsi, bool ena)
> > +{
> > + bool if_running = netif_running(vsi->netdev);
> > + int ret;
> > +
> > + if (if_running && !test_and_set_bit(ICE_VSI_DOWN, vsi->state)) {
> > + ret = ice_down(vsi);
> > + if (ret) {
> > + netdev_err(vsi->netdev, "Preparing device to toggle loopback failed\n");
> > + return ret;
> > + }
> > + }
> > + ret = ice_aq_set_mac_loopback(&vsi->back->hw, ena, NULL);
> > + if (ret)
> > + netdev_err(vsi->netdev, "Failed to toggle loopback state\n");
> > + if (if_running)
> > + ret = ice_up(vsi);
> > +
> > + return ret;
> > +}
> > +
> > /**
> > * ice_set_features - set the netdev feature flags
> > * @netdev: ptr to the netdev being adjusted
> > @@ -5960,7 +5988,10 @@ ice_set_features(struct net_device *netdev, netdev_features_t features)
> > clear_bit(ICE_FLAG_CLS_FLOWER, pf->flags);
> > }
> >
> > - return 0;
> > + if (changed & NETIF_F_LOOPBACK)
> > + ret = ice_set_loopback(vsi, !!(features & NETIF_F_LOOPBACK));
> > +
> > + return ret;
>
> Unrelated to your patch, but because you are messing with 'ret' here a bit,
> how come you return 0 when ice_is_safe_mode() shouldn't you push that
> error up so the user who is doing the setting knows it didn't actually
> work?
Safe mode is the first thing checked in ice_set_features() and in case it
is set we give the message to user about it and return 0 immediately.
So did you miss the immediate exit or are you suggesting that for safe
mode we should return some error code, not 0 which is interpreted as
'successful' command execution?
>
> > }
> >
> > /**
> > --
> > 2.27.0
> >
>
>
