[dpdk-dev] [PATCH] net/mlx5: fix debug variable initialization

[Ferruh Yigit]

On 11/4/2021 12:23 PM, Gregory Etelson wrote:
> Use `__rte_unused` macro to mask a debug variable instead of `#ifdef`.
> This way, if the variable is used in a macro, it does not depend on
> how the macro is expanded.
> 
> Fixes: 91f0e029ce5f ("net/mlx5: translate flex item pattern into matcher")
> Signed-off-by: Gregory Etelson <getelson at nvidia.com>
> ---
>   drivers/net/mlx5/mlx5_flow_flex.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_flex.c b/drivers/net/mlx5/mlx5_flow_flex.c
> index bdfa383c45..be0f9821ce 100644
> --- a/drivers/net/mlx5/mlx5_flow_flex.c
> +++ b/drivers/net/mlx5/mlx5_flow_flex.c
> @@ -222,9 +222,7 @@ mlx5_flex_flow_translate_item(struct rte_eth_dev *dev,
>   			      const struct rte_flow_item *item,
>   			      bool is_inner)
>   {
> -#ifdef RTE_LIBRTE_MLX5_DEBUG
> -	struct mlx5_priv *priv = dev->data->dev_private;
> -#endif
> +	__rte_unused struct mlx5_priv *priv = dev->data->dev_private;

Marking the variable as unused to silence compiler for some cases,
but it is indeed used, what about something like this (inspired by
sfc code):

  #if defined(RTE_LIBRTE_MLX5_DEBUG) || defined(RTE_ENABLE_ASSERT)
    struct mlx5_priv *priv = dev->data->dev_private;
  #endif

>   	const struct rte_flow_item_flex *spec, *mask;
>   	void *misc4_m = MLX5_ADDR_OF(fte_match_param, matcher,
>   				     misc_parameters_4);
>