Re: [PATCH mlx5-next 12/12] net/mlx5: Set ODP SRQ support in firmware

[Jason Gunthorpe <jgg@ziepe.ca>]

On Sun, Feb 03, 2019 at 11:03:11AM +0200, Leon Romanovsky wrote:
> On Thu, Jan 31, 2019 at 04:28:44PM -0700, Jason Gunthorpe wrote:
> > On Tue, Jan 22, 2019 at 08:48:51AM +0200, Leon Romanovsky wrote:
> > > From: Moni Shoua <monis@mellanox.com>
> > >
> > > To avoid compatibility issue with older kernels the firmware doesn't
> > > allow SRQ to work with ODP unless kernel asks for it.
> > >
> > > Signed-off-by: Moni Shoua <monis@mellanox.com>
> > > Reviewed-by: Majd Dibbiny <majd@mellanox.com>
> > > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > >  .../net/ethernet/mellanox/mlx5/core/main.c    | 53 +++++++++++++++++++
> > >  include/linux/mlx5/device.h                   |  3 ++
> > >  include/linux/mlx5/mlx5_ifc.h                 |  1 +
> > >  3 files changed, 57 insertions(+)
> > >
> > > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> > > index be81b319b0dc..b3a76df0cf6c 100644
> > > +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> > > @@ -459,6 +459,53 @@ static int handle_hca_cap_atomic(struct mlx5_core_dev *dev)
> > >  	return err;
> > >  }
> > >
> > > +static int handle_hca_cap_odp(struct mlx5_core_dev *dev)
> > > +{
> > > +	void *set_ctx;
> > > +	void *set_hca_cap;
> > > +	int set_sz = MLX5_ST_SZ_BYTES(set_hca_cap_in);
> > > +	int err;
> > > +
> > > +	if (!MLX5_CAP_GEN(dev, pg))
> > > +		return 0;
> >
> > Should a
> >
> >     if (IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING))
> >              return 0;
> >
> > Be here?
> 
> We had similar discussion in mlx5_ib main.c, but here we are talking
> about mlx5_core code, which from my point of view should represent the
> real HW capabilities without relation to kernel compilation mode.

This switch is to tell the FW that the mlx5_ib module supports the new
protocol - so having it in core code at all is really weird. I assume
there is some startup sequence reason?

Since the modularity is already wrecked it seems like an odd
reason not to add the if..

Jason