---

 memhotplug-dave/lib/radix-tree.c |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)

diff -puN lib/radix-tree.c~radix-tree-count lib/radix-tree.c
--- memhotplug/lib/radix-tree.c~radix-tree-count	2006-02-21 10:50:25.000000000 -0800
+++ memhotplug-dave/lib/radix-tree.c	2006-02-21 10:51:00.000000000 -0800
@@ -538,7 +538,9 @@ __lookup(struct radix_tree_root *root, v
 	for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
 		index++;
 		if (slot->slots[i]) {
-			results[nr_found++] = slot->slots[i];
+			if (results)
+				results[nr_found] = slot->slots[i];
+			nr_found++;
 			if (nr_found == max_items)
 				goto out;
 		}
@@ -559,6 +561,9 @@ out:
  *	them at *@results and returns the number of items which were placed at
  *	*@results.
  *
+ *	If *@results is NULL, the function will return a count of pages found,
+ *	without any actual results.
+ *
  *	The implementation is naive.
  */
 unsigned int
@@ -572,10 +577,13 @@ radix_tree_gang_lookup(struct radix_tree
 	while (ret < max_items) {
 		unsigned int nr_found;
 		unsigned long next_index;	/* Index of next search */
+		void *cur_result = NULL;
 
 		if (cur_index > max_index)
 			break;
-		nr_found = __lookup(root, results + ret, cur_index,
+		if (results)
+			cur_result = results + ret;
+		nr_found = __lookup(root, cur_result, cur_index,
 					max_items - ret, &next_index);
 		ret += nr_found;
 		if (next_index == 0)
@@ -586,6 +594,13 @@ radix_tree_gang_lookup(struct radix_tree
 }
 EXPORT_SYMBOL(radix_tree_gang_lookup);
 
+unsigned int
+radix_tree_lookup_count(struct radix_tree_root *root
+			unsigned long first_index)
+{
+	return radix_tree_gang_lookup(root, NULL, first_index, ~0);
+}
+
 /*
  * FIXME: the two tag_get()s here should use find_next_bit() instead of
  * open-coding the search.
_