On 08 Jan 12:32, Leon Romanovsky wrote:
On Thu, Jan 05, 2023 at 04:58:22PM -0800, Saeed Mahameed wrote:
On 04 Jan 10:11, Leon Romanovsky wrote:
> From: Or Har-Toov <ohartoov@xxxxxxxxxx>
>
> Using query_sepcial_contexts in order to get the correct value of
> terminate_scatter_list_mkey, as FW will change it in some configurations.
> This is done one time when the device is loading and the value is being
> saved in the device context.
>
> Signed-off-by: Or Har-Toov <ohartoov@xxxxxxxxxx>
> Reviewed-by: Michael Guralnik <michaelgur@xxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> ---
> .../net/ethernet/mellanox/mlx5/core/en_main.c | 2 +-
> .../net/ethernet/mellanox/mlx5/core/main.c | 27 +++++++++++++++++++
> include/linux/mlx5/driver.h | 1 +
> 3 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> index c76f15505a76..33d7a7095988 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> @@ -826,7 +826,7 @@ static int mlx5e_alloc_rq(struct mlx5e_params *params,
> if (rq->wqe.info.num_frags < (1 << rq->wqe.info.log_num_frags)) {
> wqe->data[f].byte_count = 0;
> wqe->data[f].lkey =
> - MLX5_TERMINATE_SCATTER_LIST_LKEY;
> + mdev->terminate_scatter_list_mkey;
> wqe->data[f].addr = 0;
> }
> }
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index 7f5db13e3550..d39d758744a0 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -1221,6 +1221,28 @@ static int mlx5_function_teardown(struct mlx5_core_dev *dev, bool boot)
> return 0;
> }
>
> +static int mlx5_get_terminate_scatter_list_mkey(struct mlx5_core_dev *dev)
> +{
> + u32 out[MLX5_ST_SZ_DW(query_special_contexts_out)] = {};
> + u32 in[MLX5_ST_SZ_DW(query_special_contexts_in)] = {};
> + int err;
> +
> + MLX5_SET(query_special_contexts_in, in, opcode,
> + MLX5_CMD_OP_QUERY_SPECIAL_CONTEXTS);
> + err = mlx5_cmd_exec_inout(dev, query_special_contexts, in, out);
> + if (err)
> + return err;
> +
> + if (MLX5_CAP_GEN(dev, terminate_scatter_list_mkey)) {
Why did you execute the command unconditionally if the output is only read
conditionally?
early exit before executing the command, older FW might fail and driver will
be unusable ..
According to the documentation, this functionality was forever, but you
are presenting valid concern.
> + dev->terminate_scatter_list_mkey =
> + cpu_to_be32(MLX5_GET(query_special_contexts_out, out,
> + terminate_scatter_list_mkey));
> + return 0;
> + }
> + dev->terminate_scatter_list_mkey = MLX5_TERMINATE_SCATTER_LIST_LKEY;
Another concern, what happens with old driver that is using the hardcoded
value with newer fw ? will it fail ? will it be accepted ?
It will be accepted and everything will work without glitches.
FW keeps backward compatibility and use MLX5_TERMINATE_SCATTER_LIST_LKEY
internally as a default.
Then please don't change mlx5e to use mdev->terminate_scatter_list_mkey in
this patch, just keep it as is and have a separate patch to change mlx5e.
