Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1456a439 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

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: default avatarMatthew Wilcox <willy@linux.intel.com>
Reviewed-by: default avatarRoss 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aa547576

lib/radix-tree.c

+23 −0
Original line number Diff line number Diff line
@@ -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.

 */