Re: [PATCH 5/9] vdso: Split linux/minmax.h

Christophe Leroy
2024-09-04T17:17:32Z

Le 03/09/2024 à 17:14, Vincenzo Frascino a écrit :
> The VDSO implementation includes headers from outside of the
> vdso/ namespace.
>
> Split linux/minmax.h to make sure that the generic library
> uses only the allowed namespace.

It is probably easier to just don't use min_t() in VDSO. Can be open
coded without impeeding readability.

>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason A. Donenfeld <Jason@zx2c4.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> ---
> include/linux/minmax.h | 28 +---------------------------
> include/vdso/minmax.h | 38 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 27 deletions(-)
> create mode 100644 include/vdso/minmax.h
>
> diff --git a/include/linux/minmax.h b/include/linux/minmax.h
> index 98008dd92153..846e3fa65c96 100644
> --- a/include/linux/minmax.h
> +++ b/include/linux/minmax.h
> @@ -6,6 +6,7 @@
> #include <linux/compiler.h>
> #include <linux/const.h>
> #include <linux/types.h>
> +#include <vdso/minmax.h>
>
> /*
> * min()/max()/clamp() macros must accomplish three things:
> @@ -84,17 +85,6 @@
> #define __types_ok3(x,y,z,ux,uy,uz) \
> (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))
>
> -#define __cmp_op_min <
> -#define __cmp_op_max >
> -
> -#define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y))
> -
> -#define __cmp_once_unique(op, type, x, y, ux, uy) \
> - ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); })
> -
> -#define __cmp_once(op, type, x, y) \
> - __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
> -
> #define __careful_cmp_once(op, x, y, ux, uy) ({ \
> __auto_type ux = (x); __auto_type uy = (y); \
> BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \
> @@ -204,22 +194,6 @@
> * Or not use min/max/clamp at all, of course.
> */
>
> -/**
> - * min_t - return minimum of two values, using the specified type
> - * @type: data type to use
> - * @x: first value
> - * @y: second value
> - */
> -#define min_t(type, x, y) __cmp_once(min, type, x, y)
> -
> -/**
> - * max_t - return maximum of two values, using the specified type
> - * @type: data type to use
> - * @x: first value
> - * @y: second value
> - */
> -#define max_t(type, x, y) __cmp_once(max, type, x, y)
> -
> /*
> * Do not check the array parameter using __must_be_array().
> * In the following legit use-case where the "array" passed is a simple pointer,
> diff --git a/include/vdso/minmax.h b/include/vdso/minmax.h
> new file mode 100644
> index 000000000000..26724f34c513
> --- /dev/null
> +++ b/include/vdso/minmax.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __VDSO_MINMAX_H
> +#define __VDSO_MINMAX_H
> +
> +#ifndef __ASSEMBLY__
> +
> +#include <linux/compiler.h>
> +
> +#define __cmp_op_min <
> +#define __cmp_op_max >
> +
> +#define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y))
> +
> +#define __cmp_once_unique(op, type, x, y, ux, uy) \
> + ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); })
> +
> +#define __cmp_once(op, type, x, y) \
> + __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
> +
> +/**
> + * min_t - return minimum of two values, using the specified type
> + * @type: data type to use
> + * @x: first value
> + * @y: second value
> + */
> +#define min_t(type, x, y) __cmp_once(min, type, x, y)
> +
> +/**
> + * max_t - return maximum of two values, using the specified type
> + * @type: data type to use
> + * @x: first value
> + * @y: second value
> + */
> +#define max_t(type, x, y) __cmp_once(max, type, x, y)
> +
> +#endif /* !__ASSEMBLY__ */
> +
> +#endif /* __VDSO_MINMAX_H */