1 files changed, 23 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/bitmap.c b/tools/testing/radix-tree/bitmap.c
new file mode 100644
index 000000000000..66ec4a24a203
--- /dev/null
+++ b/tools/testing/radix-tree/bitmap.c
@@ -0,0 +1,23 @@
+/* lib/bitmap.c pulls in at least two other files. */
+
+#include <linux/bitmap.h>
+
+void bitmap_clear(unsigned long *map, unsigned int start, int len)
+{
+        unsigned long *p = map + BIT_WORD(start);
+        const unsigned int size = start + len;
+        int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+        unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+        while (len - bits_to_clear >= 0) {
+                *p &= ~mask_to_clear;
+                len -= bits_to_clear;
+                bits_to_clear = BITS_PER_LONG;
+                mask_to_clear = ~0UL;
+                p++;
+        }
+        if (len) {
+                mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+                *p &= ~mask_to_clear;
+        }
+}