radix-tree: create node_tag_set()

Similar to node_tag_clear(), factor node_tag_set() out of
radix_tree_range_tag_if_tagged().

Link: http://lkml.kernel.org/r/1480369871-5271-51-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 8c5911eae5e228417b05e4e880d22145babc2985..a90a4371deb8b0be90d6f6951d927dedd5b6167e 100644 (file)
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -991,6 +991,22 @@ static void node_tag_clear(struct radix_tree_root *root,
                root_tag_clear(root, tag);
 }
 
+static void node_tag_set(struct radix_tree_root *root,
+                               struct radix_tree_node *node,
+                               unsigned int tag, unsigned int offset)
+{
+       while (node) {
+               if (tag_get(node, tag, offset))
+                       return;
+               tag_set(node, tag, offset);
+               offset = node->offset;
+               node = node->parent;
+       }
+
+       if (!root_tag_get(root, tag))
+               root_tag_set(root, tag);
+}
+
 /**
  *     radix_tree_tag_clear - clear a tag on a radix tree node
  *     @root:          radix tree root
@@ -1229,7 +1245,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
                unsigned long nr_to_tag,
                unsigned int iftag, unsigned int settag)
 {
-       struct radix_tree_node *parent, *node, *child;
+       struct radix_tree_node *node, *child;
        unsigned long maxindex;
        unsigned long tagged = 0;
        unsigned long index = *first_indexp;
@@ -1264,22 +1280,8 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
                        continue;
                }
 
-               /* tag the leaf */
                tagged++;
-               tag_set(node, settag, offset);
-
-               /* walk back up the path tagging interior nodes */
-               parent = node;
-               for (;;) {
-                       offset = parent->offset;
-                       parent = parent->parent;
-                       if (!parent)
-                               break;
-                       /* stop if we find a node with the tag already set */
-                       if (tag_get(parent, settag, offset))
-                               break;
-                       tag_set(parent, settag, offset);
-               }
+               node_tag_set(root, node, settag, offset);
  next:
                /* Go to next entry in node */
                index = ((index >> node->shift) + 1) << node->shift;
@@ -1301,12 +1303,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
                if (tagged >= nr_to_tag)
                        break;
        }
-       /*
-        * We need not to tag the root tag if there is no tag which is set with
-        * settag within the range from *first_indexp to last_index.
-        */
-       if (tagged > 0)
-               root_tag_set(root, settag);
+
        *first_indexp = index;
 
        return tagged;