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uapi: Provide DIV_ROUND_CLOSEST() 

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__.

Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Diederik de Haas <diederik@cknow-tech.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://patch.msgid.link/20260303-rk3588-bgcolor-v8-1-fee377037ad1@collabora.com
Signed-off-by: Daniel Stone <daniels@collabora.com>
master
Cristian Ciocaltea 2026-03-03 21:24:17 +02:00 committed by Daniel Stone
parent 25854131c0
commit de9e2b3d88
2 changed files with 19 additions and 17 deletions
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18
include/linux/math.h
View File

@ -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.

18
include/uapi/linux/const.h
View File

@ -50,4 +50,22 @@
#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 */