Re: [PATCH v1 1/2] kstrtox: Make _parse_integer() take variadic arguments

[David Laight <david.laight.linux@gmail.com>]

On Tue,  2 Jun 2026 22:29:46 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> Instead of having different functions that just use default parameters,
> combine those to use variadic arguments, so the user may call it using
> the same name.

Adding a default final parameter can be done generically:

#define one(v) v
#define first(v, ...) v
#define dflt(d, ...) first(__VA_OPT__(one(__VA_ARGS__) ,) d)

int foo(int, int);
#define foo(a, ...) foo(a, dflt(42, ## __VA_ARGS__))

See: https://godbolt.org/z/x5aao7reK

-- David

> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  lib/kstrtox.c | 6 ------
>  lib/kstrtox.h | 9 ++++++++-
>  2 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/kstrtox.c b/lib/kstrtox.c
> index edc4eb7c1bca..adc03e27e4a2 100644
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -94,12 +94,6 @@ unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned lon
>  	return rv | overflow;
>  }
>  
> -noinline
> -unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
> -{
> -	return _parse_integer_limit(s, base, p, INT_MAX);
> -}
> -
>  static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
>  {
>  	unsigned long long _res;
> diff --git a/lib/kstrtox.h b/lib/kstrtox.h
> index 158c400ca865..6c7ca3b67429 100644
> --- a/lib/kstrtox.h
> +++ b/lib/kstrtox.h
> @@ -2,10 +2,17 @@
>  #ifndef _LIB_KSTRTOX_H
>  #define _LIB_KSTRTOX_H
>  
> +#include <linux/args.h>
> +
>  #define KSTRTOX_OVERFLOW	(1U << 31)
>  const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
>  unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *res,
>  				  size_t max_chars);
> -unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res);
> +
> +#define _parse_integer0(s, base, res, ...)						\
> +	_parse_integer_limit(s, base, res, INT_MAX);
> +
> +#define _parse_integer(s, base, res, ...)						\
> +	CONCATENATE(_parse_integer, COUNT_ARGS(__VA_ARGS__))(s, base, res, __VA_ARGS__)
>  
>  #endif