Re: [PATCH v2 1/2] common/mlx5: fix build disabling

[Bruce Richardson <bruce.richardson@intel.com>]

On Sun, Oct 30, 2022 at 09:27:21AM +0100, Thomas Monjalon wrote:
> If the dependency common/mlx5 is explicitly disabled,
> but net/mlx5 is not explicitly disabled,
> Meson will read the full recipe of net/mlx5
> and will fail when accessing a variable from common/mlx5:
> drivers/net/mlx5/meson.build:76:4: ERROR: Unknown variable "mlx5_config".
> 
> The solution is to stop parsing net/mlx5 if common/mlx5 is disabled.
> The deps array must be defined before stopping, in order to automatically
> disable the build of net/mlx5 and print the reason.
> 
> The same protection is applied to other mlx5 drivers,
> so it will allow using the variable mlx5_config in future.
> 
> Fixes: 22681deead3e ("net/mlx5/hws: enable hardware steering")
> 
> Reported-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> Tested-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>  drivers/compress/mlx5/meson.build | 5 +++++
>  drivers/crypto/mlx5/meson.build   | 5 +++++
>  drivers/net/mlx5/meson.build      | 5 +++++
>  drivers/regex/mlx5/meson.build    | 5 +++++
>  drivers/vdpa/mlx5/meson.build     | 5 +++++
>  5 files changed, 25 insertions(+)
> 
> diff --git a/drivers/compress/mlx5/meson.build b/drivers/compress/mlx5/meson.build
> index 7aac329986..49ce3aff46 100644
> --- a/drivers/compress/mlx5/meson.build
> +++ b/drivers/compress/mlx5/meson.build
> @@ -9,6 +9,11 @@ endif
>  
>  fmt_name = 'mlx5_compress'
>  deps += ['common_mlx5', 'eal', 'compressdev']
> +if not ('mlx5' in common_drivers)

While this is fine as-is, I think the more usual way for checking the
presence of a component in DPDK is to check dpdk_conf. In this case the
check would be "if not dpdk_conf.has('RTE_COMMON_MLX5')". You may want to
consider using that for consistency.

/Bruce