Commit 9ee47476 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'radix-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev 

* 'radix-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev:
  radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags
  radix-tree: clear all tags in radix_tree_node_rcu_free
parents 76be97c1 144dcfc0

lib/radix-tree.c

+48 −15
Original line number Diff line number Diff line
@@ -174,14 +174,16 @@ static void radix_tree_node_rcu_free(struct rcu_head *head) 
{

	struct radix_tree_node *node =

			container_of(head, struct radix_tree_node, rcu_head);

	int i;



	/*

	 * must only free zeroed nodes into the slab. radix_tree_shrink

	 * can leave us with a non-NULL entry in the first slot, so clear

	 * that here to make sure.

	 */

	tag_clear(node, 0, 0);

	tag_clear(node, 1, 0);

	for (i = 0; i < RADIX_TREE_MAX_TAGS; i++)

		tag_clear(node, i, 0);



	node->slots[0] = NULL;

	node->count = 0;
@@ -623,6 +625,13 @@ EXPORT_SYMBOL(radix_tree_tag_get); 
 * also settag. The function stops either after tagging nr_to_tag items or

 * after reaching last_index.

 *

 * The tags must be set from the leaf level only and propagated back up the

 * path to the root. We must do this so that we resolve the full path before

 * setting any tags on intermediate nodes. If we set tags as we descend, then

 * we can get to the leaf node and find that the index that has the iftag

 * set is outside the range we are scanning. This reults in dangling tags and

 * can lead to problems with later tag operations (e.g. livelocks on lookups).

 *

 * The function returns number of leaves where the tag was set and sets

 * *first_indexp to the first unscanned index.

 * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
@@ -633,9 +642,13 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
		unsigned long nr_to_tag,

		unsigned int iftag, unsigned int settag)

{

	unsigned int height = root->height, shift;

	unsigned long tagged = 0, index = *first_indexp;

	struct radix_tree_node *open_slots[height], *slot;

	unsigned int height = root->height;

	struct radix_tree_path path[height];

	struct radix_tree_path *pathp = path;

	struct radix_tree_node *slot;

	unsigned int shift;

	unsigned long tagged = 0;

	unsigned long index = *first_indexp;



	last_index = min(last_index, radix_tree_maxindex(height));

	if (index > last_index)
@@ -655,6 +668,13 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
	shift = (height - 1) * RADIX_TREE_MAP_SHIFT;

	slot = radix_tree_indirect_to_ptr(root->rnode);



	/*

	 * we fill the path from (root->height - 2) to 0, leaving the index at

	 * (root->height - 1) as a terminator. Zero the node in the terminator

	 * so that we can use this to end walk loops back up the path.

	 */

	path[height - 1].node = NULL;



	for (;;) {

		int offset;
@@ -663,17 +683,30 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
			goto next;

		if (!tag_get(slot, iftag, offset))

			goto next;

		tag_set(slot, settag, offset);

		if (height == 1) {

			tagged++;

			goto next;

		}

		if (height > 1) {

			/* Go down one level */

			height--;

			shift -= RADIX_TREE_MAP_SHIFT;

		open_slots[height] = slot;

			path[height - 1].node = slot;

			path[height - 1].offset = offset;

			slot = slot->slots[offset];

			continue;

		}



		/* tag the leaf */

		tagged++;

		tag_set(slot, settag, offset);



		/* walk back up the path tagging interior nodes */

		pathp = &path[0];

		while (pathp->node) {

			/* stop if we find a node with the tag already set */

			if (tag_get(pathp->node, settag, pathp->offset))

				break;

			tag_set(pathp->node, settag, pathp->offset);

			pathp++;

		}



next:

		/* Go to next item at level determined by 'shift' */

		index = ((index >> shift) + 1) << shift;
@@ -688,7 +721,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
			 * last_index is guaranteed to be in the tree, what

			 * we do below cannot wander astray.

			 */

			slot = open_slots[height];

			slot = path[height - 1].node;

			height++;

			shift += RADIX_TREE_MAP_SHIFT;

		}