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

On Mon, 2019-02-04 at 14:23 -0700, Jason Gunthorpe wrote:

On Sun, Feb 03, 2019 at 11:03:11AM +0200, Leon Romanovsky wrote:

quoted

On Thu, Jan 31, 2019 at 04:28:44PM -0700, Jason Gunthorpe wrote:

quoted

On Tue, Jan 22, 2019 at 08:48:51AM +0200, Leon Romanovsky wrote:

quoted

From: Moni Shoua <redacted>

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 <redacted>
Reviewed-by: Majd Dibbiny <redacted>
Signed-off-by: Leon Romanovsky <redacted>
 .../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?

Yes, sadly this must be in startup, set_hca_cap requests must come
prior to init_hca command.

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

Agree, even better, let's compile out the whole function. I would even
consider having a separate file in mlx5/core for IB related start-up
procedures :).

Jason