1 files changed, 55 insertions, 0 deletions

diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
new file mode 100644
index 000000000000..d08302d2a42c
--- /dev/null
+++ b/lib/find_next_bit.c
@@ -0,0 +1,55 @@
+/* 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/bitops.h>
+
+int find_next_bit(const unsigned long *addr, int size, int offset)
+{
+        const unsigned long *base;
+        const int NBITS = sizeof(*addr) * 8;
+        unsigned long tmp;
+
+        base = addr;
+        if (offset) {
+                int suboffset;
+
+                addr += offset / NBITS;
+
+                suboffset = offset % NBITS;
+                if (suboffset) {
+                        tmp = *addr;
+                        tmp >>= suboffset;
+                        if (tmp)
+                                goto finish;
+                }
+
+                addr++;
+        }
+
+        while ((tmp = *addr) == 0)
+                addr++;
+
+        offset = (addr - base) * NBITS;
+
+ finish:
+        /* count the remaining bits without using __ffs() since that takes a 32-bit arg */
+        while (!(tmp & 0xff)) {
+                offset += 8;
+                tmp >>= 8;
+        }
+
+        while (!(tmp & 1)) {
+                offset++;
+                tmp >>= 1;
+        }
+
+        return offset;
+}