sched/x86: Fix overflow in cyc2ns_offset

[linux-flexiantxendom0.git] / include / linux / kernel.h

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e8b1597..a70783d 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -85,6 +85,19 @@
 }                                                      \
 )
 
+/*
+ * Multiplies an integer by a fraction, while avoiding unnecessary
+ * overflow or loss of precision.
+ */
+#define mult_frac(x, numer, denom)(                    \
+{                                                      \
+       typeof(x) quot = (x) / (denom);                 \
+       typeof(x) rem  = (x) % (denom);                 \
+       (quot * (numer)) + ((rem * (numer)) / (denom)); \
+}                                                      \
+)
+
+
 #define _RET_IP_               (unsigned long)__builtin_return_address(0)
 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })