Re: [dpdk-dev] [PATCH v2] net/mlx5: fix linkage error for glue lib

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

On Wed, Jul 25, 2018 at 04:18:54PM +0300, Shahaf Shuler wrote:
> From: Yaroslav Brustinov <ybrustin@cisco.com>
> 
> addressing a gcc 4.7.2 bug that cannot be reproduced with latter
> versions:
> 
> "bin/ld: Warning: alignment 8 of symbol `mlx5_glue' in
> src/dpdk/drivers/net/mlx5/mlx5_glue.c.21.o is smaller than 16 in
> src/dpdk/drivers/net/mlx5/mlx5_rxq.c.21.o"
> 
> Fix it be forcing the alignment of the glue lib.
> 
> Fixes: 0e83b8e536c1 ("net/mlx5: move rdma-core calls to separate file")
> Cc: stable@dpdk.org
> Cc: nelio.laranjeiro@6wind.com
> Cc: adrien.mazarguil@6wind.com
> 
> Signed-off-by: Yaroslav Brustinov <ybrustin@cisco.com>
> Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>

Except for a couple of minor nits below,

Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

> ---
> On v2:
>  - Forced alignment using alignas to the size of the cacheline.
> 
> ---
>  drivers/net/mlx5/mlx5_glue.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_glue.c b/drivers/net/mlx5/mlx5_glue.c
> index c7965e51fe..705232f614 100644
> --- a/drivers/net/mlx5/mlx5_glue.c
> +++ b/drivers/net/mlx5/mlx5_glue.c
> @@ -6,6 +6,7 @@
>  #include <errno.h>
>  #include <stddef.h>
>  #include <stdint.h>
> +#include <stdalign.h>

You should keep alphabetical order.

>  
>  /*
>   * Not needed by this file; included to work around the lack of off_t
> @@ -23,6 +24,8 @@
>  #pragma GCC diagnostic error "-Wpedantic"
>  #endif
>  
> +#include <rte_config.h>
> +
>  #include "mlx5_autoconf.h"
>  #include "mlx5_glue.h"
>  
> @@ -343,7 +346,8 @@ mlx5_glue_dv_create_qp(struct ibv_context *context,
>  #endif
>  }
>  
> -const struct mlx5_glue *mlx5_glue = &(const struct mlx5_glue){
> +alignas(RTE_CACHE_LINE_SIZE)
> +const struct mlx5_glue *mlx5_glue = &(const struct mlx5_glue) {

Extra space added before opening brace :)

>  	.version = MLX5_GLUE_VERSION,
>  	.fork_init = mlx5_glue_fork_init,
>  	.alloc_pd = mlx5_glue_alloc_pd,
> -- 
> 2.12.0
> 

-- 
Adrien Mazarguil
6WIND