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Commit d58275bc authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

radix-tree: Store a pointer to the root in each node 



Instead of having this mysterious private_data in each radix_tree_node,
store a pointer to the root, which can be useful for debugging.  This also
relieves the mm code from the duty of updating it.

Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
parent 1293d5c5

include/linux/radix-tree.h

+1 −1
Original line number Diff line number Diff line
@@ -96,7 +96,7 @@ struct radix_tree_node { 
	unsigned char	count;		/* Total entry count */

	unsigned char	exceptional;	/* Exceptional entry count */

	struct radix_tree_node *parent;		/* Used when ascending tree */

	void *private_data;			/* For tree user */

	struct radix_tree_root *root;		/* The tree we belong to */

	union {

		struct list_head private_list;	/* For tree user */

		struct rcu_head	rcu_head;	/* Used when freeing node */

lib/radix-tree.c

+8 −6
Original line number Diff line number Diff line
@@ -374,6 +374,7 @@ static void ida_dump(struct ida *ida) 
 */

static struct radix_tree_node *

radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,

			struct radix_tree_root *root,

			unsigned int shift, unsigned int offset,

			unsigned int count, unsigned int exceptional)

{
@@ -419,11 +420,12 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, 
out:

	BUG_ON(radix_tree_is_internal_node(ret));

	if (ret) {

		ret->parent = parent;

		ret->shift = shift;

		ret->offset = offset;

		ret->count = count;

		ret->exceptional = exceptional;

		ret->parent = parent;

		ret->root = root;

	}

	return ret;

}
@@ -631,7 +633,7 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, 


	do {

		struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,

								shift, 0, 1, 0);

							root, shift, 0, 1, 0);

		if (!node)

			return -ENOMEM;
@@ -828,7 +830,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, 
		shift -= RADIX_TREE_MAP_SHIFT;

		if (child == NULL) {

			/* Have to add a child node.  */

			child = radix_tree_node_alloc(gfp, node, shift,

			child = radix_tree_node_alloc(gfp, node, root, shift,

							offset, 0, 0);

			if (!child)

				return -ENOMEM;
@@ -1330,7 +1332,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, 


	for (;;) {

		if (node->shift > order) {

			child = radix_tree_node_alloc(gfp, node,

			child = radix_tree_node_alloc(gfp, node, root,

					node->shift - RADIX_TREE_MAP_SHIFT,

					offset, 0, 0);

			if (!child)
@@ -2152,8 +2154,8 @@ void **idr_get_free(struct radix_tree_root *root, 
		shift -= RADIX_TREE_MAP_SHIFT;

		if (child == NULL) {

			/* Have to add a child node.  */

			child = radix_tree_node_alloc(gfp, node, shift, offset,

							0, 0);

			child = radix_tree_node_alloc(gfp, node, root, shift,

							offset, 0, 0);

			if (!child)

				return ERR_PTR(-ENOMEM);

			all_tag_set(child, IDR_FREE);

mm/workingset.c

+2 −4
Original line number Diff line number Diff line
@@ -354,10 +354,8 @@ void workingset_update_node(struct radix_tree_node *node, void *private) 
	 * as node->private_list is protected by &mapping->tree_lock.

	 */

	if (node->count && node->count == node->exceptional) {

		if (list_empty(&node->private_list)) {

			node->private_data = mapping;

		if (list_empty(&node->private_list))

			list_lru_add(&shadow_nodes, &node->private_list);

		}

	} else {

		if (!list_empty(&node->private_list))

			list_lru_del(&shadow_nodes, &node->private_list);
@@ -435,7 +433,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, 
	 */



	node = container_of(item, struct radix_tree_node, private_list);

	mapping = node->private_data;

	mapping = container_of(node->root, struct address_space, page_tree);



	/* Coming from the list, invert the lock order */

	if (!spin_trylock(&mapping->tree_lock)) {