Re: [PATCH rdma-next 3/3] IB/mlx5: Introduce a new mini-CQE format

[Jason Gunthorpe <jgg@mellanox.com>]

On Mon, May 28, 2018 at 07:52:03PM +0300, Yishai Hadas wrote:
> On 5/28/2018 7:11 PM, Jason Gunthorpe wrote:
> >On Sun, May 27, 2018 at 01:42:34PM +0300, Leon Romanovsky wrote:
> >>From: Yonatan Cohen <yonatanc@mellanox.com>
> >>
> >>The new mini-CQE format includes the stride index, byte count and
> >>packet checksum.
> >>Stride index is needed for striding WQ feature.
> >>This patch exposes this capability and enables its setting
> >>via mlx5 UHW data as part of query device and cq creation.
> >>
> >>Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
> >>Reviewed-by: Guy Levi <guyle@mellanox.com>
> >>Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
> >>Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> >>  drivers/infiniband/hw/mlx5/cq.c   | 42 +++++++++++++++++++++++++++++----------
> >>  drivers/infiniband/hw/mlx5/main.c |  4 ++++
> >>  include/uapi/rdma/mlx5-abi.h      |  2 +-
> >>  3 files changed, 37 insertions(+), 11 deletions(-)
> >>
> >>diff --git a/drivers/infiniband/hw/mlx5/cq.c b/drivers/infiniband/hw/mlx5/cq.c
> >>index 7b4ce1a19de0..ad39d64b8108 100644
> >>+++ b/drivers/infiniband/hw/mlx5/cq.c
> >>@@ -751,6 +751,28 @@ static int alloc_cq_frag_buf(struct mlx5_ib_dev *dev,
> >>  	return 0;
> >>  }
> >>+enum {
> >>+	MLX5_CQE_RES_FORMAT_HASH = 0,
> >>+	MLX5_CQE_RES_FORMAT_CSUM = 1,
> >>+	MLX5_CQE_RES_FORMAT_CSUM_STRIDX = 3,
> >>+};
> >
> >What is this??
> 
> Those are mlx5 device values not uapi.
> 
> >>+static int mini_cqe_res_format_to_hw(struct mlx5_ib_dev *dev, u8 format)
> >>+{
> >>+	switch (format) {
> >>+	case MLX5_IB_CQE_RES_FORMAT_HASH:
> >>+		return MLX5_CQE_RES_FORMAT_HASH;
> >
> >Used here..
> 
> This is some conversion between the uapi to the device values.
> 
> >>+		mini_cqe_format =
> >>+			mini_cqe_res_format_to_hw(dev,
> >>+						  ucmd.cqe_comp_res_format);
> >
> >And format comes from a ucmd, so that enum is upai.
> 
> Correct, see mlx5-abi.h as part of this patch.
> 
> >Put it in the right place and put the right comment beside
> >struct mlx5_ib_create_cq's cqe_comp_res_format..
> >
> >And what is wrong with the user space patches? Where is the update to
> >enum mlx5dv_cqe_comp_res_format ? And why is this wrong?
> >
> 
> See the first patch from below PR [1], it brings the new enum value to the
> user area as part of kernel-headers/rdma/mlx5-abi.h.
> 
> [1] https://github.com/linux-rdma/rdma-core/pull/337
> 
> >struct mlx5dv_cq_init_attr {
> >         uint64_t comp_mask; /* Use enum mlx5dv_cq_init_attr_mask */
> >         uint8_t cqe_comp_res_format; /* Use enum mlx5dv_cqe_comp_res_format */
> >                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> 
> The user space uses the DV prefix (e.g. MLX5DV_CQE_RES_FORMAT_CSUM_STRIDX),
> no change from previous flags around enum mlx5dv_cqe_comp_res_format.

This still needs eventual cleaning up in the verbs_abi.h way.

But OK, this is not what I thought.

Jason