radix-tree: rewrite radix_tree_tag_clear

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

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 24 deletions

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 5234a95024a3..ee56562e0a2d 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -768,44 +768,40 @@ EXPORT_SYMBOL(radix_tree_tag_set);
 void *radix_tree_tag_clear(struct radix_tree_root *root,
                         unsigned long index, unsigned int tag)
 {
-        struct radix_tree_node *node = NULL;
-        struct radix_tree_node *slot = NULL;
-        unsigned int height, shift;
+        struct radix_tree_node *node, *parent;
+        unsigned long maxindex;
+        unsigned int shift;
         int uninitialized_var(offset);
 
-        height = root->height;
-        if (index > radix_tree_maxindex(height))
-                goto out;
-
-        shift = height * RADIX_TREE_MAP_SHIFT;
-        slot = root->rnode;
+        shift = radix_tree_load_root(root, &node, &maxindex);
+        if (index > maxindex)
+                return NULL;
 
-        while (shift) {
-                if (slot == NULL)
-                        goto out;
-                if (!radix_tree_is_indirect_ptr(slot))
-                        break;
-                slot = indirect_to_ptr(slot);
+        parent = NULL;
 
+        while (radix_tree_is_indirect_ptr(node)) {
                 shift -= RADIX_TREE_MAP_SHIFT;
                 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
-                node = slot;
-                slot = slot->slots[offset];
+
+                parent = indirect_to_ptr(node);
+                offset = radix_tree_descend(parent, &node, offset);
         }
 
-        if (slot == NULL)
+        if (node == NULL)
                 goto out;
 
-        while (node) {
-                if (!tag_get(node, tag, offset))
+        index >>= shift;
+
+        while (parent) {
+                if (!tag_get(parent, tag, offset))
                         goto out;
-                tag_clear(node, tag, offset);
-                if (any_tag_set(node, tag))
+                tag_clear(parent, tag, offset);
+                if (any_tag_set(parent, tag))
                         goto out;
 
                 index >>= RADIX_TREE_MAP_SHIFT;
                 offset = index & RADIX_TREE_MAP_MASK;
-                node = node->parent;
+                parent = parent->parent;
         }
 
         /* clear the root's tag bit */
@@ -813,7 +809,7 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
                 root_tag_clear(root, tag);
 
 out:
-        return slot;
+        return node;
 }
 EXPORT_SYMBOL(radix_tree_tag_clear);