tux3: Update libklib/libklib.h for v4.19

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

fs/tux3/user/libklib/libklib.h

@@ -70,7 +70,23 @@
  * arguments just once each.
  */
 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
+/**
+ * round_up - round up to next specified power of 2
+ * @x: the value to round
+ * @y: multiple to round up to (must be a power of 2)
+ *
+ * Rounds @x up to next multiple of @y (which must be a power of 2).
+ * To perform arbitrary rounding up, use roundup() below.
+ */
 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+/**
+ * round_down - round down to next specified power of 2
+ * @x: the value to round
+ * @y: multiple to round down to (must be a power of 2)
+ *
+ * Rounds @x down to next multiple of @y (which must be a power of 2).
+ * To perform arbitrary rounding down, use rounddown() below.
+ */
 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 
 /**
@@ -84,6 +100,37 @@
 
 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
 
+/**
+ * roundup - round up to the next specified multiple
+ * @x: the value to up
+ * @y: multiple to round up to
+ *
+ * Rounds @x up to next multiple of @y. If @y will always be a power
+ * of 2, consider using the faster round_up().
+ *
+ * The `const' here prevents gcc-3.3 from calling __divdi3
+ */
+#define roundup(x, y) (					\
+{							\
+	const typeof(y) __y = y;			\
+	(((x) + (__y - 1)) / __y) * __y;		\
+}							\
+)
+/**
+ * rounddown - round down to next specified multiple
+ * @x: the value to round
+ * @y: multiple to round down to
+ *
+ * Rounds @x down to next multiple of @y. If @y will always be a power
+ * of 2, consider using the faster round_down().
+ */
+#define rounddown(x, y) (				\
+{							\
+	typeof(x) __x = (x);				\
+	__x - (__x % (y));				\
+}							\
+)
+
 /*
  * min()/max()/clamp() macros must accomplish three things:
  *