radix tree test harness

This code is mostly from Andrew Morton and Nick Piggin; tarball downloaded
from http://ozlabs.org/~akpm/rtth.tar.gz with sha1sum
0ce679db9ec047296b5d1ff7a1dfaa03a7bef1bd

Some small modifications were necessary to the test harness to fix the
build with the current Linux source code.

I also made minor modifications to automatically test the radix-tree.c
and radix-tree.h files that are in the current source tree, as opposed
to a copied and slightly modified version.  I am sure more could be done
to tidy up the harness, as well as adding more tests.

[koct9i@gmail.com: fix compilation]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/find_next_bit.c b/tools/testing/radix-tree/find_next_bit.c
new file mode 100644
index 000000000000..d1c2178bb2d4
--- /dev/null
+++ b/tools/testing/radix-tree/find_next_bit.c
@@ -0,0 +1,57 @@
+/* find_next_bit.c: fallback find next bit implementation
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/bitops.h>
+
+#define BITOP_WORD(nr)          ((nr) / BITS_PER_LONG)
+
+/*
+ * Find the next set bit in a memory region.
+ */
+unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
+                            unsigned long offset)
+{
+        const unsigned long *p = addr + BITOP_WORD(offset);
+        unsigned long result = offset & ~(BITS_PER_LONG-1);
+        unsigned long tmp;
+
+        if (offset >= size)
+                return size;
+        size -= result;
+        offset %= BITS_PER_LONG;
+        if (offset) {
+                tmp = *(p++);
+                tmp &= (~0UL << offset);
+                if (size < BITS_PER_LONG)
+                        goto found_first;
+                if (tmp)
+                        goto found_middle;
+                size -= BITS_PER_LONG;
+                result += BITS_PER_LONG;
+        }
+        while (size & ~(BITS_PER_LONG-1)) {
+                if ((tmp = *(p++)))
+                        goto found_middle;
+                result += BITS_PER_LONG;
+                size -= BITS_PER_LONG;
+        }
+        if (!size)
+                return result;
+        tmp = *p;
+
+found_first:
+        tmp &= (~0UL >> (BITS_PER_LONG - size));
+        if (tmp == 0UL)         /* Are any bits set? */
+                return result + size;   /* Nope. */
+found_middle:
+        return result + __ffs(tmp);
+}