[PATCH v4 1/4] uapi: Provide DIV_ROUND_CLOSEST()
From: Cristian Ciocaltea <hidden>
Date: 2025-12-19 21:47:30
Also in:
dri-devel, linux-rockchip, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Currently DIV_ROUND_CLOSEST() is only available for the kernel via include/linux/math.h. Expose it to userland as well by adding __KERNEL_DIV_ROUND_CLOSEST() as a common definition in uapi. Additionally, ensure it allows building ISO C applications by switching from the 'typeof' GNU extension to the ISO-friendly __typeof__. Signed-off-by: Cristian Ciocaltea <redacted> --- include/linux/math.h | 18 +----------------- include/uapi/linux/const.h | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/include/linux/math.h b/include/linux/math.h
index 6dc1d1d32fbc..1e8fb3efbc8c 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h@@ -89,23 +89,7 @@ } \ ) -/* - * Divide positive or negative dividend by positive or negative divisor - * and round to closest integer. Result is undefined for negative - * divisors if the dividend variable type is unsigned and for negative - * dividends if the divisor variable type is unsigned. - */ -#define DIV_ROUND_CLOSEST(x, divisor)( \ -{ \ - typeof(x) __x = x; \ - typeof(divisor) __d = divisor; \ - (((typeof(x))-1) > 0 || \ - ((typeof(divisor))-1) > 0 || \ - (((__x) > 0) == ((__d) > 0))) ? \ - (((__x) + ((__d) / 2)) / (__d)) : \ - (((__x) - ((__d) / 2)) / (__d)); \ -} \ -) +#define DIV_ROUND_CLOSEST __KERNEL_DIV_ROUND_CLOSEST /* * Same as above but for u64 dividends. divisor must be a 32-bit * number.
diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h
index b8f629ef135f..471877322f47 100644
--- a/include/uapi/linux/const.h
+++ b/include/uapi/linux/const.h@@ -50,4 +50,21 @@ #define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) +/* + * Divide positive or negative dividend by positive or negative divisor + * and round to closest integer. Result is undefined for negative + * divisors if the dividend variable type is unsigned and for negative + * dividends if the divisor variable type is unsigned. + */ +#define __KERNEL_DIV_ROUND_CLOSEST(x, divisor)( \ +{ \ + __typeof__(x) __x = x; \ + __typeof__(divisor) __d = divisor; \ + (((__typeof__(x))-1) > 0 || \ + ((__typeof__(divisor))-1) > 0 || \ + (((__x) > 0) == ((__d) > 0))) ? \ + (((__x) + ((__d) / 2)) / (__d)) : \ + (((__x) - ((__d) / 2)) / (__d)); \ +} \ +) #endif /* _UAPI_LINUX_CONST_H */
--
2.51.2