On Tue, Jul 30, 2019 at 4:08 PM Saeed Mahameed <sae...@mellanox.com> wrote:
>
> On Tue, 2019-07-30 at 11:52 -0400, Willem de Bruijn wrote:
> > On Mon, Jul 29, 2019 at 7:50 PM Saeed Mahameed <sae...@mellanox.com>
> > wrote:
> > > From: Huy Nguyen <h...@mellanox.com>
> > >
> > > When user enables LRO via ethtool and if the RQ mode is legacy,
> > > mlx5e_fix_features drops the request without any explanation.
> > > Add netdev_warn to cover this case.
> > >
> > > Fixes: 6c3a823e1e9c ("net/mlx5e: RX, Remove HW LRO support in
> > > legacy RQ")
> > > Signed-off-by: Huy Nguyen <h...@mellanox.com>
> > > Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
> > > ---
> > > drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > > b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > > index 47eea6b3a1c3..776eb46d263d 100644
> > > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > > @@ -3788,9 +3788,10 @@ static netdev_features_t
> > > mlx5e_fix_features(struct net_device *netdev,
> > > netdev_warn(netdev, "Dropping C-tag vlan
> > > stripping offload due to S-tag vlan\n");
> > > }
> > > if (!MLX5E_GET_PFLAG(params, MLX5E_PFLAG_RX_STRIDING_RQ)) {
> > > - features &= ~NETIF_F_LRO;
> > > - if (params->lro_en)
> > > + if (features & NETIF_F_LRO) {
> > > netdev_warn(netdev, "Disabling LRO, not
> > > supported in legacy RQ\n");
> >
> > This warns about "Disabling LRO" on an enable request?
> >
>
> no, this warning appears only when lro is already enabled and might
> conflict with any other feature requested by user (hence
> mlx5e_fix_features), e.g when moving away from striding rq in this
> example, we will force lro to off.
Ok. The previous commit mentioned "totally remove LRO support in
Legacy RQ". This handles the additional case when moving a queue into
legacy mode that still had LRO enabled. I see.
>
>
> > More fundamentally, it appears that the device does not advertise
> > the feature as configurable in netdev_hw_features as of commit
> > 6c3a823e1e9c ("net/mlx5e: RX, Remove HW LRO support in
> > legacy RQ"), so shouldn't this be caught by the device driver
> > independent ethtool code?
>
> when hw doesn't support MLX5E_PFLAG_RX_STRIDING_RQ then yes, you will
> never hit this code path, but when hw does support
> MLX5E_PFLAG_RX_STRIDING_RQ and you want to turn striding rq off, then
> lro will be forced to off (if it was enabled in first space) and a
> warning msg will be shown.
Got it, thanks.
