Re: [PATCH 2/2] net/mlx5: enforce Tx num of segments limitation

["Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>]

On Wed, Aug 23, 2017 at 10:33:58AM +0300, Shahaf Shuler wrote:
> Mellanox NICs has a limitation on the number of mbuf segments a multi
> segment mbuf can have. The max number depends on the Tx offloads requested.
> 
> The current code not enforce such limitation, which might cause
> malformed WQEs to be written to the device.

Avoid acronyms in the commit message (at least on first occurrence), not all
people knows what a WQE is and getting such information is not easy.

> This commit adds verification for the number of mbuf segments posted
> to the device. In case of overflow the packet will not be sent.
> Debug prints were added to help application identify the cause for such
> case.
> 
> Cc: stable@dpdk.org
> 
> Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
> ---
> 
> This patch should be applied only after the series:
> http://dpdk.org/dev/patchwork/patch/27367/
> 
> ---
>  drivers/net/mlx5/mlx5_defs.h         |  3 ++-
>  drivers/net/mlx5/mlx5_prm.h          |  3 +++
>  drivers/net/mlx5/mlx5_rxtx.c         | 30 +++++++++++++++++++++++++++---
>  drivers/net/mlx5/mlx5_rxtx_vec_sse.c |  8 ++++++++
>  drivers/net/mlx5/mlx5_txq.c          | 27 +++++++++++++++++++++++++++
>  5 files changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_prm.h b/drivers/net/mlx5/mlx5_prm.h
> index 608072f7e..87244e7db 100644
> --- a/drivers/net/mlx5/mlx5_prm.h
> +++ b/drivers/net/mlx5/mlx5_prm.h
> @@ -154,6 +154,9 @@
>  /* Default mark value used when none is provided. */
>  #define MLX5_FLOW_MARK_DEFAULT 0xffffff
>  
> +/* Maximum number of DS in WQE. */
> +#define MLX5_MAX_DS (63)
> +

Why the parenthesis?

Thanks,

-- 
Nélio Laranjeiro
6WIND