Merge branch 'v2.6.25-rc3-lockdep' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / include / linux / log2.h

diff --git a/include/linux/log2.h b/include/linux/log2.h
index c8cf5e8ef1717d40cde2768fd0608f29924b1545..25b808631cd92c50d10cf6a31b2d9b9942b62ac9 100644 (file)
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -190,4 +190,20 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
        __rounddown_pow_of_two(n)               \
  )
 
+/**
+ * order_base_2 - calculate the (rounded up) base 2 order of the argument
+ * @n: parameter
+ *
+ * The first few values calculated by this routine:
+ *  ob2(0) = 0
+ *  ob2(1) = 0
+ *  ob2(2) = 1
+ *  ob2(3) = 2
+ *  ob2(4) = 2
+ *  ob2(5) = 3
+ *  ... and so on.
+ */
+
+#define order_base_2(n) ilog2(roundup_pow_of_two(n))
+
 #endif /* _LINUX_LOG2_H */