Re: [PATCH next v2 02/11] minmax: Use _Static_assert() instead of static_assert()

From: Jani Nikula
Date: Mon Feb 26 2024 - 04:58:22 EST


On Sun, 25 Feb 2024, David Laight <David.Laight@xxxxxxxxxx> wrote:
> The wrapper just adds two more lines of error output when the test fails.

There are only a handful of places in kernel code that use
_Static_assert() directly. Nearly 900 instances of static_assert().

Are we now saying it's fine to use _Static_assert() directly all over
the place? People will copy-paste and cargo cult.

BR,
Jani.

>
> Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
> ---
> include/linux/minmax.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> Changes for v2:
> - Typographical and spelling corrections to the commit messages.
> Patches unchanged.
>
> diff --git a/include/linux/minmax.h b/include/linux/minmax.h
> index 63c45865b48a..900eec7a28e5 100644
> --- a/include/linux/minmax.h
> +++ b/include/linux/minmax.h
> @@ -48,7 +48,7 @@
> #define __cmp_once(op, x, y, unique_x, unique_y) ({ \
> typeof(x) unique_x = (x); \
> typeof(y) unique_y = (y); \
> - static_assert(__types_ok(x, y), \
> + _Static_assert(__types_ok(x, y), \
> #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
> __cmp(op, unique_x, unique_y); })
>
> @@ -137,11 +137,11 @@
> typeof(val) unique_val = (val); \
> typeof(lo) unique_lo = (lo); \
> typeof(hi) unique_hi = (hi); \
> - static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
> + _Static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
> (lo) <= (hi), true), \
> "clamp() low limit " #lo " greater than high limit " #hi); \
> - static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
> - static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
> + _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
> + _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
> __clamp(unique_val, unique_lo, unique_hi); })
>
> #define __careful_clamp(val, lo, hi) ({ \

--
Jani Nikula, Intel