1 files changed, 40 insertions, 0 deletions

diff --git a/include/linux/util_macros.h b/include/linux/util_macros.h
new file mode 100644
index 000000000000..d5f4fb69dba3
--- /dev/null
+++ b/include/linux/util_macros.h
@@ -0,0 +1,40 @@
+#ifndef _LINUX_HELPER_MACROS_H_
+#define _LINUX_HELPER_MACROS_H_
+
+#define __find_closest(x, a, as, op)                                    \
+({                                                                      \
+        typeof(as) __fc_i, __fc_as = (as) - 1;                          \
+        typeof(x) __fc_x = (x);                                         \
+        typeof(*a) *__fc_a = (a);                                       \
+        for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) {                  \
+                if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] +        \
+                                                __fc_a[__fc_i + 1], 2)) \
+                        break;                                          \
+        }                                                               \
+        (__fc_i);                                                       \
+})
+
+/**
+ * find_closest - locate the closest element in a sorted array
+ * @x: The reference value.
+ * @a: The array in which to look for the closest element. Must be sorted
+ *  in ascending order.
+ * @as: Size of 'a'.
+ *
+ * Returns the index of the element closest to 'x'.
+ */
+#define find_closest(x, a, as) __find_closest(x, a, as, <=)
+
+/**
+ * find_closest_descending - locate the closest element in a sorted array
+ * @x: The reference value.
+ * @a: The array in which to look for the closest element. Must be sorted
+ *  in descending order.
+ * @as: Size of 'a'.
+ *
+ * Similar to find_closest() but 'a' is expected to be sorted in descending
+ * order.
+ */
+#define find_closest_descending(x, a, as) __find_closest(x, a, as, >=)
+
+#endif