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>

diff --git a/include/linux/math.h b/include/linux/math.h
index 6dc1d1d32fbc81889e0f8dc3b3ad4178628206a3..1e8fb3efbc8ce9099e11f43db6ff3088f1570e46 100644 (file)
--- 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 b8f629ef135f356f552b9aa9dd73356167503134..565f309b9df8b158b8c5f91ccec25b55e957480d 100644 (file)
--- a/include/uapi/linux/const.h
+++ b/include/uapi/linux/const.h
@@ -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 */