Re: [PATCH net-next v3 1/4] crypto: caam: Avoid unused imx8m_machine_match variable

[Horia Geanta]

On 7/2/2024 9:56 PM, Breno Leitao wrote:
> If caam module is built without OF support, the compiler returns the
> following warning:
> 
> 	drivers/crypto/caam/ctrl.c:83:34: warning: 'imx8m_machine_match' defined but not used [-Wunused-const-variable=]
> 
> imx8m_machine_match is only referenced by of_match_node(), which is set
> to NULL if CONFIG_OF is not set, as of commit 5762c20593b6b ("dt: Add
> empty of_match_node() macro"):
> 
> 	#define of_match_node(_matches, _node)  NULL
> 
> Do not create imx8m_machine_match if CONFIG_OF is not set.
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202407011309.cpTuOGdg-lkp@xxxxxxxxx/
> Suggested-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  drivers/crypto/caam/ctrl.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
> index bd418dea586d..d4b39184dbdb 100644
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -80,6 +80,7 @@ static void build_deinstantiation_desc(u32 *desc, int handle)
>  	append_jump(desc, JUMP_CLASS_CLASS1 | JUMP_TYPE_HALT);
>  }
>  
> +#ifdef CONFIG_OF
>  static const struct of_device_id imx8m_machine_match[] = {
>  	{ .compatible = "fsl,imx8mm", },
>  	{ .compatible = "fsl,imx8mn", },
> @@ -88,6 +89,7 @@ static const struct of_device_id imx8m_machine_match[] = {
>  	{ .compatible = "fsl,imx8ulp", },
>  	{ }
>  };
> +#endif
>  
Shouldn't using __maybe_unused instead of the ifdeffery be preferred
in this case?

I know my comment comes late (patch has been merged to net-next), sorry for this.
Still I'd like to clarify this for future.

Thanks,
Horia