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Date: Fri, 09 Apr 2021 10:38:39 +0100
From: Paul Cercueil <paul@...pouillou.net>
To: Masahiro Yamada <masahiroy@...nel.org>
Cc: Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
GPIO SUBSYSTEM <linux-gpio@...r.kernel.org>,
Arnd Bergmann <arnd@...db.de>,
Linus Walleij <linus.walleij@...aro.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-mips@...r.kernel.org
Subject: Re: [PATCH 1/2] linux/kconfig.h: replace IF_ENABLED() with PTR_IF()
in <linux/kernel.h>
Le ven. 9 avril 2021 à 17:30, Masahiro Yamada <masahiroy@...nel.org> a
écrit :
> On Fri, Apr 9, 2021 at 5:15 PM Paul Cercueil <paul@...pouillou.net>
> wrote:
>>
>> Hi Masahiro,
>>
>> Le ven. 9 avril 2021 à 5:58, Masahiro Yamada
>> <masahiroy@...nel.org> a
>> écrit :
>> > <linux/kconfig.h> is included from all the kernel-space source
>> files,
>> > including C, assembly, linker scripts. It is intended to contain
>> > 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.
>> >
>> > Also, <linux/kconfig.h> is no longer self-contained because NULL
>> is
>> > defined in <linux/stddef.h>.
>> >
>> > Move IF_ENABLED() out to <linux/kernel.h> as PTR_IF().
>> >
>> > PTR_IF(IS_ENABLED(CONFIG_FOO), ...) is slightly longer than
>> > IF_ENABLED(CONFIG_FOO, ...), but it is not a big deal because
>> > sub-systems often define dedicated macros such as of_match_ptr(),
>> > pm_ptr() etc. for common use-cases.
>>
>> What's the idea behind changing IF_ENABLED() to PTR_IF()? You didn't
>> explain that. What's wrong with IF_ENABLED()?
>
>
> PTR_IF() is a more generalized variant, which I believe is
> a better fit in <linux/kernel.h>
> The first parameter does not need to be a CONFIG option,
> but any expression.
Fair enough, but we could still have IF_ENABLED as a specialized
variant of PTR_IF:
#define IF_ENABLED(cfg, ptr) PTR_IF(IS_ENABLED(cfg), (ptr))
-Paul
>
>
>> Cheers,
>> -Paul
>>
>> > Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
>> > ---
>> >
>> > drivers/pinctrl/pinctrl-ingenic.c | 20 ++++++++++----------
>> > include/linux/kconfig.h | 6 ------
>> > include/linux/kernel.h | 2 ++
>> > 3 files changed, 12 insertions(+), 16 deletions(-)
>> >
>> > diff --git a/drivers/pinctrl/pinctrl-ingenic.c
>> > b/drivers/pinctrl/pinctrl-ingenic.c
>> > index f2746125b077..b21e2ae4528d 100644
>> > --- a/drivers/pinctrl/pinctrl-ingenic.c
>> > +++ b/drivers/pinctrl/pinctrl-ingenic.c
>> > @@ -2496,43 +2496,43 @@ static int __init
>> > ingenic_pinctrl_probe(struct platform_device *pdev)
>> > static const struct of_device_id ingenic_pinctrl_of_match[] = {
>> > {
>> > .compatible = "ingenic,jz4740-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4740,
>> &jz4740_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4740),
>> &jz4740_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,jz4725b-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4725B,
>> &jz4725b_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4725B),
>> &jz4725b_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,jz4760-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4760,
>> &jz4760_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4760),
>> &jz4760_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,jz4760b-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4760,
>> &jz4760_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4760),
>> &jz4760_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,jz4770-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4770,
>> &jz4770_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4770),
>> &jz4770_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,jz4780-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_JZ4780,
>> &jz4780_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4780),
>> &jz4780_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,x1000-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_X1000,
>> &x1000_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1000),
>> &x1000_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,x1000e-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_X1000,
>> &x1000_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1000),
>> &x1000_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,x1500-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_X1500,
>> &x1500_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1500),
>> &x1500_chip_info)
>> > },
>> > {
>> > .compatible = "ingenic,x1830-pinctrl",
>> > - .data = IF_ENABLED(CONFIG_MACH_X1830,
>> &x1830_chip_info)
>> > + .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1830),
>> &x1830_chip_info)
>> > },
>> > { /* sentinel */ },
>> > };
>> > diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
>> > index 24a59cb06963..cc8fa109cfa3 100644
>> > --- a/include/linux/kconfig.h
>> > +++ b/include/linux/kconfig.h
>> > @@ -70,10 +70,4 @@
>> > */
>> > #define IS_ENABLED(option) __or(IS_BUILTIN(option),
>> > IS_MODULE(option))
>> >
>> > -/*
>> > - * IF_ENABLED(CONFIG_FOO, ptr) evaluates to (ptr) if CONFIG_FOO
>> is
>> > set to 'y'
>> > - * or 'm', NULL otherwise.
>> > - */
>> > -#define IF_ENABLED(option, ptr) (IS_ENABLED(option) ? (ptr) :
>> NULL)
>> > -
>> > #endif /* __LINUX_KCONFIG_H */
>> > diff --git a/include/linux/kernel.h b/include/linux/kernel.h
>> > index 5b7ed6dc99ac..8685ca4cf287 100644
>> > --- a/include/linux/kernel.h
>> > +++ b/include/linux/kernel.h
>> > @@ -38,6 +38,8 @@
>> > #define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned
>> > long)(p), (a)))
>> > #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) -
>> 1)) == 0)
>> >
>> > +#define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
>> > +
>> > /* generic data direction definitions */
>> > #define READ 0
>> > #define WRITE 1
>> > --
>> > 2.27.0
>> >
>>
>>
>
>
> --
> Best Regards
> Masahiro Yamada
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