[PATCH] math64: prevent double calculation of DIV64_U64_ROUND_UP() arguments

[Roman Gushchin]

Cause the DIV64_U64_ROUND_UP(ll, d) macro to cache
the result of (d) expression in a local variable to
avoid double calculation, which might bring unexpected
side effects.

Signed-off-by: Roman Gushchin <guro@xxxxxx>
---
 include/linux/math64.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/math64.h b/include/linux/math64.h
index 94af3d9c73e7..bb2c84afb80c 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -281,6 +281,7 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
 }
 #endif /* mul_u64_u32_div */
 
-#define DIV64_U64_ROUND_UP(ll, d)	div64_u64((ll) + (d) - 1, (d))
+#define DIV64_U64_ROUND_UP(ll, d)	\
+	({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })
 
 #endif /* _LINUX_MATH64_H */
-- 
2.17.1