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Commit 4589ba6d authored by Ross Zwisler's avatar Ross Zwisler Committed by Linus Torvalds
Browse files

radix-tree: rewrite radix_tree_tag_get 



Use the new multi-order support functions to rewrite
radix_tree_tag_get()

Signed-off-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarMatthew Wilcox <willy@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 00f47b58

lib/radix-tree.c

+18 −26
Original line number Diff line number Diff line
@@ -831,45 +831,37 @@ EXPORT_SYMBOL(radix_tree_tag_clear); 
int radix_tree_tag_get(struct radix_tree_root *root,

			unsigned long index, unsigned int tag)

{

	unsigned int height, shift;

	struct radix_tree_node *node;

	struct radix_tree_node *node, *parent;

	unsigned long maxindex;

	unsigned int shift;



	/* check the root's tag bit */

	if (!root_tag_get(root, tag))

		return 0;



	node = rcu_dereference_raw(root->rnode);

	shift = radix_tree_load_root(root, &node, &maxindex);

	if (index > maxindex)

		return 0;

	if (node == NULL)

		return 0;



	if (!radix_tree_is_indirect_ptr(node))

		return (index == 0);

	node = indirect_to_ptr(node);



	height = node->path & RADIX_TREE_HEIGHT_MASK;

	if (index > radix_tree_maxindex(height))

		return 0;

	while (radix_tree_is_indirect_ptr(node)) {

		int offset;



	shift = (height - 1) * RADIX_TREE_MAP_SHIFT;

		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;



	for ( ; ; ) {

		int offset;

		parent = indirect_to_ptr(node);

		offset = radix_tree_descend(parent, &node, offset);



		if (node == NULL)

		if (!node)

			return 0;

		node = indirect_to_ptr(node);



		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		if (!tag_get(node, tag, offset))

		if (!tag_get(parent, tag, offset))

			return 0;

		if (height == 1)

			return 1;

		node = rcu_dereference_raw(node->slots[offset]);

		if (!radix_tree_is_indirect_ptr(node))

			return 1;

		shift -= RADIX_TREE_MAP_SHIFT;

		height--;

		if (node == RADIX_TREE_RETRY)

			break;

	}



	return 1;

}

EXPORT_SYMBOL(radix_tree_tag_get);