Re: [PATCH mlx5-next 1/6] net/mlx5: Enable SW-defined RoCEv2 UDP source port

[Saeed Mahameed <saeedm@mellanox.com>]

On Wed, 2020-03-18 at 11:52 +0200, Leon Romanovsky wrote:
> From: Mark Zhang <markz@mellanox.com>
> 
> When this is enabled, UDP source port for RoCEv2 packets are defined
> by software instead of firmware.
> 
> Signed-off-by: Mark Zhang <markz@mellanox.com>
> Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> ---
>  .../net/ethernet/mellanox/mlx5/core/main.c    | 39
> +++++++++++++++++++
>  include/linux/mlx5/mlx5_ifc.h                 |  5 ++-
>  2 files changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index 6b38ec72215a..bdc73370297b 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -585,6 +585,39 @@ static int handle_hca_cap(struct mlx5_core_dev
> *dev)
>  	return err;
>  }
>  
> +static int handle_hca_cap_roce(struct mlx5_core_dev *dev)
> +{
> +	int set_sz = MLX5_ST_SZ_BYTES(set_hca_cap_in);
> +	void *set_hca_cap;
> +	void *set_ctx;
> +	int err;
> +
> +	if (!MLX5_CAP_GEN(dev, roce))
> +		return 0;
> +
> +	err = mlx5_core_get_caps(dev, MLX5_CAP_ROCE);
> +	if (err)
> +		return err;
> +
> +	if (MLX5_CAP_ROCE(dev, sw_r_roce_src_udp_port) ||
> +	    !MLX5_CAP_ROCE_MAX(dev, sw_r_roce_src_udp_port))
> +		return 0;
> +
> +	set_ctx = kzalloc(set_sz, GFP_KERNEL);
> +	if (!set_ctx)
> +		return -ENOMEM;
> +

all the sisters of this function allocate this and free it
consecutively, why not allocate it from outside once, pass it to all
handle_hca_cap_xyz functions, each one will memset it and reuse it.
see below.

> +	set_hca_cap = MLX5_ADDR_OF(set_hca_cap_in, set_ctx,
> capability);
> +	memcpy(set_hca_cap, dev->caps.hca_cur[MLX5_CAP_ROCE],
> +	       MLX5_ST_SZ_BYTES(roce_cap));
> +	MLX5_SET(roce_cap, set_hca_cap, sw_r_roce_src_udp_port, 1);
> +
> +	err = set_caps(dev, set_ctx, set_sz,
> MLX5_SET_HCA_CAP_OP_MOD_ROCE);
> +

Do we really need to fail the whole driver if we just try to set a non
mandatory cap ?

> +	kfree(set_ctx);
> +	return err;
> +}
> +
>  static int set_hca_cap(struct mlx5_core_dev *dev)
>  {
>  	int err;

let's allocate the set_ctx in this parent function and pass it to all
hca cap handlers;

set_sz = MLX5_ST_SZ_BYTES(set_hca_cap_in);
set_ctx = kzalloc(set_sz, GFP_KERNEL);

> @@ -607,6 +640,12 @@ static int set_hca_cap(struct mlx5_core_dev
> *dev)
>  		goto out;
>  	}
>  
> +	err = handle_hca_cap_roce(dev);
> +	if (err) {
> +		mlx5_core_err(dev, "handle_hca_cap_roce failed\n");
> +		goto out;
> +	}
> +
>  out:
>  	return err;
>  }
> diff --git a/include/linux/mlx5/mlx5_ifc.h
> b/include/linux/mlx5/mlx5_ifc.h
> index 208bf1127be7..bb217c3f30da 100644
> --- a/include/linux/mlx5/mlx5_ifc.h
> +++ b/include/linux/mlx5/mlx5_ifc.h
> @@ -74,6 +74,7 @@ enum {
>  	MLX5_SET_HCA_CAP_OP_MOD_GENERAL_DEVICE        = 0x0,
>  	MLX5_SET_HCA_CAP_OP_MOD_ODP                   = 0x2,
>  	MLX5_SET_HCA_CAP_OP_MOD_ATOMIC                = 0x3,
> +	MLX5_SET_HCA_CAP_OP_MOD_ROCE                  = 0x4,
>  };
>  
>  enum {
> @@ -902,7 +903,9 @@ struct
> mlx5_ifc_per_protocol_networking_offload_caps_bits {
>  
>  struct mlx5_ifc_roce_cap_bits {
>  	u8         roce_apm[0x1];
> -	u8         reserved_at_1[0x1f];
> +	u8         reserved_at_1[0x3];
> +	u8         sw_r_roce_src_udp_port[0x1];
> +	u8         reserved_at_5[0x1b];
>  
>  	u8         reserved_at_20[0x60];
>