diff --git a/sys/compat/linuxkpi/common/include/linux/math64.h b/sys/compat/linuxkpi/common/include/linux/math64.h
--- a/sys/compat/linuxkpi/common/include/linux/math64.h
+++ b/sys/compat/linuxkpi/common/include/linux/math64.h
@@ -31,6 +31,7 @@
 #define	_LINUXKPI_LINUX_MATH64_H
 
 #include <sys/stdint.h>
+#include <linux/log2.h>
 
 #define	do_div(n, base) ({			\
 	uint32_t __base = (base);		\
@@ -108,6 +109,41 @@
 	return ((x / div) * y + (rem * y) / div);
 }
 
+static inline uint64_t
+mul_u64_u64_div_u64(uint64_t x, uint64_t y, uint64_t z)
+{
+	uint64_t res;
+
+	res = 0;
+	/* Overflow on x * y possible? */
+	if ((ilog2(x) + ilog2(y)) > 62) {
+		uint64_t remainder;
+		int d;
+
+		/*
+		 * Do: (y / z) * x;  y = y % z.
+		 * If we overflow the result will never fit. Otherwise the final
+		 * div64_u64() will do the x * y / z missing we already prepared
+		 * for the final result of (y % z) * x / z in addition to res.
+		 */
+		res = div64_u64_rem(y, z, &remainder);
+		res *= x;
+		y = remainder;
+
+		/* Re-check with new y. */
+		d = ilog2(x) + ilog2(y) - 62;
+		if (d > 0) {
+			/* We cannot help anymore. Reduce precision. */
+			y >>= d;
+			z >>= d;
+			/* Avoid div0. */
+			if (z == 0)
+				return (res);
+		}
+	}
+	return (res + div64_u64(x * y, z));
+}
+
 static inline uint64_t
 mul_u64_u32_shr(uint64_t x, uint32_t y, unsigned int shift)
 {