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Commit daff89f3 authored by Jonathan Corbet's avatar Jonathan Corbet Committed by Linus Torvalds
Browse files

[PATCH] radix-tree documentation cleanups 



Documentation changes to help radix tree users avoid overrunning the tags
array.  RADIX_TREE_TAGS moves to linux/radix-tree.h and is now known as
RADIX_TREE_MAX_TAGS (Nick Piggin's idea).  Tag parameters are changed to
unsigned, and some comments are updated.

Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 57070d01

include/linux/radix-tree.h

+8 −5
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ do { \ 
	(root)->rnode = NULL;						\

} while (0)



#define RADIX_TREE_MAX_TAGS 2



int radix_tree_insert(struct radix_tree_root *, unsigned long, void *);

void *radix_tree_lookup(struct radix_tree_root *, unsigned long);

void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
@@ -55,15 +57,16 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results, 
int radix_tree_preload(gfp_t gfp_mask);

void radix_tree_init(void);

void *radix_tree_tag_set(struct radix_tree_root *root,

			unsigned long index, int tag);

			unsigned long index, unsigned int tag);

void *radix_tree_tag_clear(struct radix_tree_root *root,

			unsigned long index, int tag);

			unsigned long index, unsigned int tag);

int radix_tree_tag_get(struct radix_tree_root *root,

			unsigned long index, int tag);

			unsigned long index, unsigned int tag);

unsigned int

radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,

		unsigned long first_index, unsigned int max_items, int tag);

int radix_tree_tagged(struct radix_tree_root *root, int tag);

		unsigned long first_index, unsigned int max_items,

		unsigned int tag);

int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag);



static inline void radix_tree_preload_end(void)

{

lib/radix-tree.c

+27 −22
Original line number Diff line number Diff line
@@ -37,7 +37,6 @@ 
#else

#define RADIX_TREE_MAP_SHIFT	3	/* For more stressful testing */

#endif

#define RADIX_TREE_TAGS		2



#define RADIX_TREE_MAP_SIZE	(1UL << RADIX_TREE_MAP_SHIFT)

#define RADIX_TREE_MAP_MASK	(RADIX_TREE_MAP_SIZE-1)
@@ -48,7 +47,7 @@ 
struct radix_tree_node {

	unsigned int	count;

	void		*slots[RADIX_TREE_MAP_SIZE];

	unsigned long	tags[RADIX_TREE_TAGS][RADIX_TREE_TAG_LONGS];

	unsigned long	tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];

};



struct radix_tree_path {
@@ -135,17 +134,20 @@ int radix_tree_preload(gfp_t gfp_mask) 
	return ret;

}



static inline void tag_set(struct radix_tree_node *node, int tag, int offset)

static inline void tag_set(struct radix_tree_node *node, unsigned int tag,

		int offset)

{

	__set_bit(offset, node->tags[tag]);

}



static inline void tag_clear(struct radix_tree_node *node, int tag, int offset)

static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,

		int offset)

{

	__clear_bit(offset, node->tags[tag]);

}



static inline int tag_get(struct radix_tree_node *node, int tag, int offset)

static inline int tag_get(struct radix_tree_node *node, unsigned int tag,

		int offset)

{

	return test_bit(offset, node->tags[tag]);

}
@@ -154,7 +156,7 @@ static inline int tag_get(struct radix_tree_node *node, int tag, int offset) 
 * Returns 1 if any slot in the node has this tag set.

 * Otherwise returns 0.

 */

static inline int any_tag_set(struct radix_tree_node *node, int tag)

static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)

{

	int idx;

	for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
@@ -180,7 +182,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) 
{

	struct radix_tree_node *node;

	unsigned int height;

	char tags[RADIX_TREE_TAGS];

	char tags[RADIX_TREE_MAX_TAGS];

	int tag;



	/* Figure out what the height should be.  */
@@ -197,7 +199,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) 
	 * Prepare the tag status of the top-level node for propagation

	 * into the newly-pushed top-level node(s)

	 */

	for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {

	for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {

		tags[tag] = 0;

		if (any_tag_set(root->rnode, tag))

			tags[tag] = 1;
@@ -211,7 +213,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) 
		node->slots[0] = root->rnode;



		/* Propagate the aggregated tag info into the new root */

		for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {

		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {

			if (tags[tag])

				tag_set(node, tag, 0);

		}
@@ -349,14 +351,15 @@ EXPORT_SYMBOL(radix_tree_lookup); 
 *	@index:		index key

 *	@tag: 		tag index

 *

 *	Set the search tag corresponging to @index in the radix tree.  From

 *	Set the search tag (which must be < RADIX_TREE_MAX_TAGS)

 *	corresponding to @index in the radix tree.  From

 *	the root all the way down to the leaf node.

 *

 *	Returns the address of the tagged item.   Setting a tag on a not-present

 *	item is a bug.

 */

void *radix_tree_tag_set(struct radix_tree_root *root,

			unsigned long index, int tag)

			unsigned long index, unsigned int tag)

{

	unsigned int height, shift;

	struct radix_tree_node *slot;
@@ -390,7 +393,8 @@ EXPORT_SYMBOL(radix_tree_tag_set); 
 *	@index:		index key

 *	@tag: 		tag index

 *

 *	Clear the search tag corresponging to @index in the radix tree.  If

 *	Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)

 *	corresponding to @index in the radix tree.  If

 *	this causes the leaf node to have no tags set then clear the tag in the

 *	next-to-leaf node, etc.

 *
@@ -398,7 +402,7 @@ EXPORT_SYMBOL(radix_tree_tag_set); 
 *	has the same return value and semantics as radix_tree_lookup().

 */

void *radix_tree_tag_clear(struct radix_tree_root *root,

			unsigned long index, int tag)

			unsigned long index, unsigned int tag)

{

	struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;

	struct radix_tree_node *slot;
@@ -450,7 +454,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); 
 * radix_tree_tag_get - get a tag on a radix tree node

 * @root:		radix tree root

 * @index:		index key

 * @tag: 		tag index

 * @tag: 		tag index (< RADIX_TREE_MAX_TAGS)

 *

 * Return values:

 *
@@ -459,7 +463,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); 
 * -1: tag present, unset

 */

int radix_tree_tag_get(struct radix_tree_root *root,

			unsigned long index, int tag)

			unsigned long index, unsigned int tag)

{

	unsigned int height, shift;

	struct radix_tree_node *slot;
@@ -592,7 +596,7 @@ EXPORT_SYMBOL(radix_tree_gang_lookup); 
 */

static unsigned int

__lookup_tag(struct radix_tree_root *root, void **results, unsigned long index,

	unsigned int max_items, unsigned long *next_index, int tag)

	unsigned int max_items, unsigned long *next_index, unsigned int tag)

{

	unsigned int nr_found = 0;

	unsigned int shift;
@@ -646,7 +650,7 @@ __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, 
 *	@results:	where the results of the lookup are placed

 *	@first_index:	start the lookup from this key

 *	@max_items:	place up to this many items at *results

 *	@tag:		the tag index

 *	@tag:		the tag index (< RADIX_TREE_MAX_TAGS)

 *

 *	Performs an index-ascending scan of the tree for present items which

 *	have the tag indexed by @tag set.  Places the items at *@results and
@@ -654,7 +658,8 @@ __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, 
 */

unsigned int

radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,

		unsigned long first_index, unsigned int max_items, int tag)

		unsigned long first_index, unsigned int max_items,

		unsigned int tag)

{

	const unsigned long max_index = radix_tree_maxindex(root->height);

	unsigned long cur_index = first_index;
@@ -716,7 +721,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) 
	struct radix_tree_node *slot;

	unsigned int height, shift;

	void *ret = NULL;

	char tags[RADIX_TREE_TAGS];

	char tags[RADIX_TREE_MAX_TAGS];

	int nr_cleared_tags;

	int tag;

	int offset;
@@ -751,7 +756,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) 
	 * Clear all tags associated with the just-deleted item

	 */

	nr_cleared_tags = 0;

	for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {

	for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {

		tags[tag] = 1;

		if (tag_get(pathp->node, tag, pathp->offset)) {

			tag_clear(pathp->node, tag, pathp->offset);
@@ -763,7 +768,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) 
	}



	for (pathp--; nr_cleared_tags && pathp->node; pathp--) {

		for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {

		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {

			if (tags[tag])

				continue;
@@ -801,7 +806,7 @@ EXPORT_SYMBOL(radix_tree_delete); 
 *	@root:		radix tree root

 *	@tag:		tag to test

 */

int radix_tree_tagged(struct radix_tree_root *root, int tag)

int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)

{

  	struct radix_tree_node *rnode;

  	rnode = root->rnode;