Re: [PATCH 1/2] linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>

[Masahiro Yamada]

On Fri, Apr 9, 2021 at 5:15 PM Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:
>
> Hi Masahiro,
>
> Le ven. 9 avril 2021 à 5:58, Masahiro Yamada <masahiroy@xxxxxxxxxx> 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.







> Cheers,
> -Paul
>
> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > ---
> >
> >  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