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authorMatthew Wilcox <willy@linux.intel.com>2016-05-20 17:02:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 17:58:30 -0700
commit1456a439fc2dcc0c3d1a2d7af1fd83962813aaee (patch)
tree48bf013e6dae70a848ad0f501f60855e8d77929d /lib
parentaa5475760235672f316fbf29cdfb82a75016dbdf (diff)
downloadlinux-1456a439fc2dcc0c3d1a2d7af1fd83962813aaee.tar.gz
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@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@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>
Diffstat (limited to 'lib')
-rw-r--r--lib/radix-tree.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 6900f7b67c49..272ce810d29b 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -405,6 +405,29 @@ static inline unsigned long radix_tree_maxindex(unsigned int height)
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.
*/