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| author | Matthew Wilcox <willy@linux.intel.com> | 2016-05-20 17:02:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-20 17:58:30 -0700 |
| commit | 1456a439fc2dcc0c3d1a2d7af1fd83962813aaee (patch) | |
| tree | 48bf013e6dae70a848ad0f501f60855e8d77929d | |
| parent | aa5475760235672f316fbf29cdfb82a75016dbdf (diff) | |
| download | linux-1456a439fc2dcc0c3d1a2d7af1fd83962813aaee.tar.gz linux-1456a439fc2dcc0c3d1a2d7af1fd83962813aaee.tar.bz2 linux-1456a439fc2dcc0c3d1a2d7af1fd83962813aaee.zip | |
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>
| -rw-r--r-- | lib/radix-tree.c | 23 |
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. */ |