[PATCH 22/30] radix-tree: Rewrite radix_tree_tag_set

[Matthew Wilcox]

From: Ross Zwisler <ross.zwis...@linux.intel.com>

Use the new multi-order support functions to rewrite radix_tree_tag_set()

Signed-off-by: Ross Zwisler <ross.zwis...@linux.intel.com>
Signed-off-by: Matthew Wilcox <wi...@linux.intel.com>
---
 lib/radix-tree.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index efcb8ed4b96b..6d9b328705a1 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -729,35 +729,32 @@ EXPORT_SYMBOL(radix_tree_lookup);
 void *radix_tree_tag_set(struct radix_tree_root *root,
                        unsigned long index, unsigned int tag)
 {
-       unsigned int height, shift;
-       struct radix_tree_node *slot;
-
-       height = root->height;
-       BUG_ON(index > radix_tree_maxindex(height));
+       struct radix_tree_node *node, *parent;
+       unsigned long maxindex;
+       unsigned int shift;
 
-       slot = indirect_to_ptr(root->rnode);
-       shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
+       shift = radix_tree_load_root(root, &node, &maxindex);
+       BUG_ON(index > maxindex);
 
-       while (height > 0) {
-               int offset;
+       while (radix_tree_is_indirect_ptr(node)) {
+               unsigned offset;
 
-               offset = (index >> shift) & RADIX_TREE_MAP_MASK;
-               if (!tag_get(slot, tag, offset))
-                       tag_set(slot, tag, offset);
-               slot = slot->slots[offset];
-               BUG_ON(slot == NULL);
-               if (!radix_tree_is_indirect_ptr(slot))
-                       break;
-               slot = indirect_to_ptr(slot);
                shift -= RADIX_TREE_MAP_SHIFT;
-               height--;
+               offset = (index >> shift) & RADIX_TREE_MAP_MASK;
+
+               parent = indirect_to_ptr(node);
+               offset = radix_tree_descend(parent, &node, offset);
+               BUG_ON(!node);
+
+               if (!tag_get(parent, tag, offset))
+                       tag_set(parent, tag, offset);
        }
 
        /* set the root's tag bit */
-       if (slot && !root_tag_get(root, tag))
+       if (!root_tag_get(root, tag))
                root_tag_set(root, tag);
 
-       return slot;
+       return node;
 }
 EXPORT_SYMBOL(radix_tree_tag_set);
 
-- 
2.8.0.rc3