Re: [PATCH v2] linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>
From: Stephen Rothwell <hidden>
Date: 2021-05-08 02:00:16
Also in:
linux-gpio, linux-kbuild, lkml
Hi Masahiro, On Thu, 6 May 2021 02:45:15 +0900 Masahiro Yamada [off-list ref] 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.
quoted hunk ↗ jump to hunk
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@kernel.org> --- 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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