Hi Masahiro,
On Thu, 6 May 2021 02:45:15 +0900 Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> <linux/kconfig.h> is included from all the kernel-space source files,
> including C, assembly, linker scripts. It is intended to contain a
> minimal set of macros to evaluate CONFIG options.
>
> IF_ENABLED() is an intruder here because (x ? y : z) is C code, which
> should not be included from assembly files or linker scripts.
Except it doesn't matter unless IF_ENABLED() is used by one of those.
> Also, <linux/kconfig.h> is no longer self-contained because NULL is
> defined in <linux/stddef.h>.
Again, it doesn't matter unless IF_ENABLED() is used.
> Move IF_ENABLED() out to <linux/kernel.h> as PTR_IF(). PTF_IF()
> takes the general boolean expression instead of a CONFIG option
> so that it fits better in <linux/kernel.h>.
>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> ---
>
> Changes in v2:
> - Keep PTF_IF macro in pinctrl-ingenic.c
>
> drivers/pinctrl/pinctrl-ingenic.c | 2 ++
> include/linux/kconfig.h | 6 ------
> include/linux/kernel.h | 2 ++
> 3 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pinctrl/pinctrl-ingenic.c b/drivers/pinctrl/pinctrl-ingenic.c
> index 651a36b9dcc0..0ee69f8e20b2 100644
> --- a/drivers/pinctrl/pinctrl-ingenic.c
> +++ b/drivers/pinctrl/pinctrl-ingenic.c
> @@ -3854,6 +3854,8 @@ static int __init ingenic_pinctrl_probe(struct platform_device *pdev)
> return 0;
> }
>
> +#define IF_ENABLED(cfg, ptr) PTR_IF(IS_ENABLED(cfg), (ptr))
> +
> static const struct of_device_id ingenic_pinctrl_of_match[] = {
> {
> .compatible = "ingenic,jz4730-pinctrl",
You also need to include linux/kernel.h in
drivers/pinctrl/pinctrl-ingenic.c (for completeness).
Also, I don't understand why the use of IF_ENABLED doesn't produce
"defined but not used" warnings (if the function "ptr" is not marked as
__maybe_unused) ...
Also, if there is only one user of IF_ENABLED (and therefore PTR_IF),
why not just put it in that file and save me rebuilding the world again
every day because kernel.h is changed (again). I guess that is going
to happen just because kconfig.h is being changed and that is also
included by everything :-(
Also, is anyone else ever going to use PTR_IF() without having to also
use IS_ENABLED()?
So, in case it is not obvious, I consider this patch unnecessary churn
(as was probably the patch that introduced IF_ENABLED in the first
place).
As an aside, this should not have been added to the kbuild tree in
linux-next until after -rc1 was released ...
--
Cheers,
Stephen Rothwell
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