/*
* Copyright (C) 2001 Momchil Velikov
* Portions Copyright (C) 2001 Christoph Hellwig
+ * Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
#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)
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 {
- struct radix_tree_node *node, **slot;
+ struct radix_tree_node *node;
int offset;
};
#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)
-static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH];
+static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly;
/*
* Radix tree node cache.
* success, return zero, with preemption disabled. On error, return -ENOMEM
* with preemption not disabled.
*/
-int radix_tree_preload(int gfp_mask)
+int radix_tree_preload(gfp_t gfp_mask)
{
struct radix_tree_preload *rtp;
struct radix_tree_node *node;
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)
{
- if (!test_bit(offset, &node->tags[tag][0]))
- __set_bit(offset, &node->tags[tag][0]);
+ __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][0]);
+ __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][0]);
+ return test_bit(offset, node->tags[tag]);
+}
+
+/*
+ * 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, unsigned int tag)
+{
+ int idx;
+ for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
+ if (node->tags[tag][idx])
+ return 1;
+ }
+ return 0;
}
/*
{
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. */
* 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++) {
- int idx;
-
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
tags[tag] = 0;
- for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
- if (root->rnode->tags[tag][idx]) {
- tags[tag] = 1;
- break;
- }
- }
+ if (any_tag_set(root->rnode, tag))
+ tags[tag] = 1;
}
do {
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);
}
int radix_tree_insert(struct radix_tree_root *root,
unsigned long index, void *item)
{
- struct radix_tree_node *node = NULL, *tmp, **slot;
+ struct radix_tree_node *node = NULL, *slot;
unsigned int height, shift;
int offset;
int error;
return error;
}
- slot = &root->rnode;
+ slot = root->rnode;
height = root->height;
shift = (height-1) * RADIX_TREE_MAP_SHIFT;
offset = 0; /* uninitialised var warning */
- while (height > 0) {
- if (*slot == NULL) {
+ do {
+ if (slot == NULL) {
/* Have to add a child node. */
- if (!(tmp = radix_tree_node_alloc(root)))
+ if (!(slot = radix_tree_node_alloc(root)))
return -ENOMEM;
- *slot = tmp;
- if (node)
+ if (node) {
+ node->slots[offset] = slot;
node->count++;
+ } else
+ root->rnode = slot;
}
/* Go a level down */
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- node = *slot;
- slot = (struct radix_tree_node **)(node->slots + offset);
+ node = slot;
+ slot = node->slots[offset];
shift -= RADIX_TREE_MAP_SHIFT;
height--;
- }
+ } while (height > 0);
- if (*slot != NULL)
+ if (slot != NULL)
return -EEXIST;
- if (node) {
- node->count++;
- BUG_ON(tag_get(node, 0, offset));
- BUG_ON(tag_get(node, 1, offset));
- }
- *slot = item;
+ BUG_ON(!node);
+ node->count++;
+ node->slots[offset] = item;
+ BUG_ON(tag_get(node, 0, offset));
+ BUG_ON(tag_get(node, 1, offset));
+
return 0;
}
EXPORT_SYMBOL(radix_tree_insert);
-/**
- * radix_tree_lookup - perform lookup operation on a radix tree
- * @root: radix tree root
- * @index: index key
- *
- * Lookup the item at the position @index in the radix tree @root.
- */
-void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
+static inline void **__lookup_slot(struct radix_tree_root *root,
+ unsigned long index)
{
unsigned int height, shift;
struct radix_tree_node **slot;
height--;
}
- return *slot;
+ return (void **)slot;
+}
+
+/**
+ * radix_tree_lookup_slot - lookup a slot in a radix tree
+ * @root: radix tree root
+ * @index: index key
+ *
+ * Lookup the slot corresponding to the position @index in the radix tree
+ * @root. This is useful for update-if-exists operations.
+ */
+void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
+{
+ return __lookup_slot(root, index);
+}
+EXPORT_SYMBOL(radix_tree_lookup_slot);
+
+/**
+ * radix_tree_lookup - perform lookup operation on a radix tree
+ * @root: radix tree root
+ * @index: index key
+ *
+ * Lookup the item at the position @index in the radix tree @root.
+ */
+void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
+{
+ void **slot;
+
+ slot = __lookup_slot(root, index);
+ return slot != NULL ? *slot : NULL;
}
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;
+ struct radix_tree_node *slot;
height = root->height;
if (index > radix_tree_maxindex(height))
return NULL;
shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
- slot = &root->rnode;
+ slot = root->rnode;
while (height > 0) {
int offset;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- tag_set(*slot, tag, offset);
- slot = (struct radix_tree_node **)((*slot)->slots + offset);
- BUG_ON(*slot == NULL);
+ if (!tag_get(slot, tag, offset))
+ tag_set(slot, tag, offset);
+ slot = slot->slots[offset];
+ BUG_ON(slot == NULL);
shift -= RADIX_TREE_MAP_SHIFT;
height--;
}
- return *slot;
+ return slot;
}
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.
*
* 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;
unsigned int height, shift;
void *ret = NULL;
shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
pathp->node = NULL;
- pathp->slot = &root->rnode;
+ slot = root->rnode;
while (height > 0) {
int offset;
- if (*pathp->slot == NULL)
+ if (slot == NULL)
goto out;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
pathp[1].offset = offset;
- pathp[1].node = *pathp[0].slot;
- pathp[1].slot = (struct radix_tree_node **)
- (pathp[1].node->slots + offset);
+ pathp[1].node = slot;
+ slot = slot->slots[offset];
pathp++;
shift -= RADIX_TREE_MAP_SHIFT;
height--;
}
- ret = *pathp[0].slot;
+ ret = slot;
if (ret == NULL)
goto out;
do {
- int idx;
-
- tag_clear(pathp[0].node, tag, pathp[0].offset);
- for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
- if (pathp[0].node->tags[tag][idx])
- goto out;
- }
+ if (!tag_get(pathp->node, tag, pathp->offset))
+ goto out;
+ tag_clear(pathp->node, tag, pathp->offset);
+ if (any_tag_set(pathp->node, tag))
+ goto out;
pathp--;
- } while (pathp[0].node);
+ } while (pathp->node);
out:
return ret;
}
#ifndef __KERNEL__ /* Only the test harness uses this at present */
/**
- * radix_tree_tag_get - get a tag on a radix tree node
- * @root: radix tree root
- * @index: index key
- * @tag: tag index
+ * radix_tree_tag_get - get a tag on a radix tree node
+ * @root: radix tree root
+ * @index: index key
+ * @tag: tag index (< RADIX_TREE_MAX_TAGS)
*
- * Return the search tag corresponging to @index in the radix tree.
+ * Return values:
*
- * Returns zero if the tag is unset, or if there is no corresponding item
- * in the tree.
+ * 0: tag not present
+ * 1: tag present, set
+ * -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;
+ struct radix_tree_node *slot;
int saw_unset_tag = 0;
height = root->height;
return 0;
shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
- slot = &root->rnode;
+ slot = root->rnode;
for ( ; ; ) {
int offset;
- if (*slot == NULL)
+ if (slot == NULL)
return 0;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
* This is just a debug check. Later, we can bale as soon as
* we see an unset tag.
*/
- if (!tag_get(*slot, tag, offset))
+ if (!tag_get(slot, tag, offset))
saw_unset_tag = 1;
if (height == 1) {
- int ret = tag_get(*slot, tag, offset);
+ int ret = tag_get(slot, tag, offset);
BUG_ON(ret && saw_unset_tag);
- return ret;
+ return ret ? 1 : -1;
}
- slot = (struct radix_tree_node **)((*slot)->slots + offset);
+ slot = slot->slots[offset];
shift -= RADIX_TREE_MAP_SHIFT;
height--;
}
unsigned int max_items, unsigned long *next_index)
{
unsigned int nr_found = 0;
- unsigned int shift;
- unsigned int height = root->height;
+ unsigned int shift, height;
struct radix_tree_node *slot;
+ unsigned long i;
+
+ height = root->height;
+ if (height == 0)
+ goto out;
shift = (height-1) * RADIX_TREE_MAP_SHIFT;
slot = root->rnode;
- while (height > 0) {
- unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK;
+ for ( ; height > 1; height--) {
- for ( ; i < RADIX_TREE_MAP_SIZE; i++) {
+ for (i = (index >> shift) & RADIX_TREE_MAP_MASK ;
+ i < RADIX_TREE_MAP_SIZE; i++) {
if (slot->slots[i] != NULL)
break;
index &= ~((1UL << shift) - 1);
}
if (i == RADIX_TREE_MAP_SIZE)
goto out;
- height--;
- if (height == 0) { /* Bottom level: grab some items */
- unsigned long j = index & RADIX_TREE_MAP_MASK;
- for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
- index++;
- if (slot->slots[j]) {
- results[nr_found++] = slot->slots[j];
- if (nr_found == max_items)
- goto out;
- }
- }
- }
shift -= RADIX_TREE_MAP_SHIFT;
slot = slot->slots[i];
}
+
+ /* Bottom level: grab some items */
+ for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
+ index++;
+ if (slot->slots[i]) {
+ results[nr_found++] = slot->slots[i];
+ if (nr_found == max_items)
+ goto out;
+ }
+ }
out:
*next_index = index;
return nr_found;
*/
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;
* @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
*/
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;
}
EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
+/**
+ * radix_tree_shrink - shrink height of a radix tree to minimal
+ * @root radix tree root
+ */
+static inline void radix_tree_shrink(struct radix_tree_root *root)
+{
+ /* try to shrink tree height */
+ while (root->height > 1 &&
+ root->rnode->count == 1 &&
+ root->rnode->slots[0]) {
+ struct radix_tree_node *to_free = root->rnode;
+
+ root->rnode = to_free->slots[0];
+ root->height--;
+ /* must only free zeroed nodes into the slab */
+ tag_clear(to_free, 0, 0);
+ tag_clear(to_free, 1, 0);
+ to_free->slots[0] = NULL;
+ to_free->count = 0;
+ radix_tree_node_free(to_free);
+ }
+}
+
/**
* radix_tree_delete - delete an item from a radix tree
* @root: radix tree root
{
struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
struct radix_tree_path *orig_pathp;
+ 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;
height = root->height;
if (index > radix_tree_maxindex(height))
shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
pathp->node = NULL;
- pathp->slot = &root->rnode;
-
- while (height > 0) {
- int offset;
+ slot = root->rnode;
- if (*pathp->slot == NULL)
+ for ( ; height > 0; height--) {
+ if (slot == NULL)
goto out;
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- pathp[1].offset = offset;
- pathp[1].node = *pathp[0].slot;
- pathp[1].slot = (struct radix_tree_node **)
- (pathp[1].node->slots + offset);
pathp++;
+ offset = (index >> shift) & RADIX_TREE_MAP_MASK;
+ pathp->offset = offset;
+ pathp->node = slot;
+ slot = slot->slots[offset];
shift -= RADIX_TREE_MAP_SHIFT;
- height--;
}
- ret = *pathp[0].slot;
+ ret = slot;
if (ret == NULL)
goto out;
/*
* Clear all tags associated with the just-deleted item
*/
- memset(tags, 0, sizeof(tags));
- do {
- int tag;
-
- nr_cleared_tags = RADIX_TREE_TAGS;
- for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
- int idx;
+ nr_cleared_tags = 0;
+ 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);
+ if (!any_tag_set(pathp->node, tag)) {
+ tags[tag] = 0;
+ nr_cleared_tags++;
+ }
+ }
+ }
+ for (pathp--; nr_cleared_tags && pathp->node; pathp--) {
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
if (tags[tag])
continue;
- tag_clear(pathp[0].node, tag, pathp[0].offset);
-
- for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
- if (pathp[0].node->tags[tag][idx]) {
- tags[tag] = 1;
- nr_cleared_tags--;
- break;
- }
+ tag_clear(pathp->node, tag, pathp->offset);
+ if (any_tag_set(pathp->node, tag)) {
+ tags[tag] = 1;
+ nr_cleared_tags--;
}
}
- pathp--;
- } while (pathp[0].node && nr_cleared_tags);
+ }
- pathp = orig_pathp;
- *pathp[0].slot = NULL;
- while (pathp[0].node && --pathp[0].node->count == 0) {
- pathp--;
- BUG_ON(*pathp[0].slot == NULL);
- *pathp[0].slot = NULL;
- radix_tree_node_free(pathp[1].node);
+ /* Now free the nodes we do not need anymore */
+ for (pathp = orig_pathp; pathp->node; pathp--) {
+ pathp->node->slots[pathp->offset] = NULL;
+ pathp->node->count--;
+
+ if (pathp->node->count) {
+ if (pathp->node == root->rnode)
+ radix_tree_shrink(root);
+ goto out;
+ }
+
+ /* Node with zero slots in use so free it */
+ radix_tree_node_free(pathp->node);
}
- if (root->rnode == NULL)
- root->height = 0;
+ root->rnode = NULL;
+ root->height = 0;
out:
return ret;
}
* @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)
{
- int idx;
-
- if (!root->rnode)
- return 0;
- for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
- if (root->rnode->tags[tag][idx])
- return 1;
- }
- return 0;
+ struct radix_tree_node *rnode;
+ rnode = root->rnode;
+ if (!rnode)
+ return 0;
+ return any_tag_set(rnode, tag);
}
EXPORT_SYMBOL(radix_tree_tagged);
git://git.onelab.eu / linux-2.6.git / blobdiff