From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Subject: radix-tree: introduce radix_tree_load_root()
All the tree walking functions start with some variant of this code;
centralise it in one place so we're not chasing subtly different bugs
everywhere.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Kirill Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/radix-tree.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff -puN lib/radix-tree.c~radix-tree-introduce-radix_tree_load_root lib/radix-tree.c
--- a/lib/radix-tree.c~radix-tree-introduce-radix_tree_load_root
+++ a/lib/radix-tree.c
@@ -405,6 +405,29 @@ static inline unsigned long radix_tree_m
return height_to_maxindex[height];
}
+static inline unsigned long node_maxindex(struct radix_tree_node *node)
+{
+ return radix_tree_maxindex(node->path & RADIX_TREE_HEIGHT_MASK);
+}
+
+static unsigned radix_tree_load_root(struct radix_tree_root *root,
+ struct radix_tree_node **nodep, unsigned long *maxindex)
+{
+ struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
+
+ *nodep = node;
+
+ if (likely(radix_tree_is_indirect_ptr(node))) {
+ node = indirect_to_ptr(node);
+ *maxindex = node_maxindex(node);
+ return (node->path & RADIX_TREE_HEIGHT_MASK) *
+ RADIX_TREE_MAP_SHIFT;
+ }
+
+ *maxindex = 0;
+ return 0;
+}
+
/*
* Extend a radix tree so it can store key @index.
*/
_
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
