diff options
Diffstat (limited to 'libdde_linux26/contrib/lib/radix-tree.c')
| -rw-r--r-- | libdde_linux26/contrib/lib/radix-tree.c | 1240 |
1 files changed, 0 insertions, 1240 deletions
diff --git a/libdde_linux26/contrib/lib/radix-tree.c b/libdde_linux26/contrib/lib/radix-tree.c deleted file mode 100644 index 4bb42a03..00000000 --- a/libdde_linux26/contrib/lib/radix-tree.c +++ /dev/null @@ -1,1240 +0,0 @@ -/* - * Copyright (C) 2001 Momchil Velikov - * Portions Copyright (C) 2001 Christoph Hellwig - * Copyright (C) 2005 SGI, Christoph Lameter - * Copyright (C) 2006 Nick Piggin - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2, or (at - * your option) any later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ - -#include <linux/errno.h> -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/radix-tree.h> -#include <linux/percpu.h> -#include <linux/slab.h> -#include <linux/notifier.h> -#include <linux/cpu.h> -#include <linux/gfp.h> -#include <linux/string.h> -#include <linux/bitops.h> -#include <linux/rcupdate.h> - - -#ifdef __KERNEL__ -#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) -#else -#define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ -#endif - -#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) -#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) - -#define RADIX_TREE_TAG_LONGS \ - ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) - -struct radix_tree_node { - unsigned int height; /* Height from the bottom */ - unsigned int count; - struct rcu_head rcu_head; - void *slots[RADIX_TREE_MAP_SIZE]; - unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; -}; - -struct radix_tree_path { - struct radix_tree_node *node; - int offset; -}; - -#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) -#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ - RADIX_TREE_MAP_SHIFT)) - -/* - * The height_to_maxindex array needs to be one deeper than the maximum - * path as height 0 holds only 1 entry. - */ -static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; - -/* - * Radix tree node cache. - */ -static struct kmem_cache *radix_tree_node_cachep; - -/* - * Per-cpu pool of preloaded nodes - */ -struct radix_tree_preload { - int nr; - struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; -}; -static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; - -static inline gfp_t root_gfp_mask(struct radix_tree_root *root) -{ - return root->gfp_mask & __GFP_BITS_MASK; -} - -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, unsigned int tag, - int offset) -{ - __clear_bit(offset, node->tags[tag]); -} - -static inline int tag_get(struct radix_tree_node *node, unsigned int tag, - int offset) -{ - return test_bit(offset, node->tags[tag]); -} - -static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) -{ - root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); -} - -static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) -{ - root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); -} - -static inline void root_tag_clear_all(struct radix_tree_root *root) -{ - root->gfp_mask &= __GFP_BITS_MASK; -} - -static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) -{ - return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); -} - -/* - * 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; -} -/* - * This assumes that the caller has performed appropriate preallocation, and - * that the caller has pinned this thread of control to the current CPU. - */ -static struct radix_tree_node * -radix_tree_node_alloc(struct radix_tree_root *root) -{ - struct radix_tree_node *ret = NULL; - gfp_t gfp_mask = root_gfp_mask(root); - - if (!(gfp_mask & __GFP_WAIT)) { - struct radix_tree_preload *rtp; - - /* - * Provided the caller has preloaded here, we will always - * succeed in getting a node here (and never reach - * kmem_cache_alloc) - */ - rtp = &__get_cpu_var(radix_tree_preloads); - if (rtp->nr) { - ret = rtp->nodes[rtp->nr - 1]; - rtp->nodes[rtp->nr - 1] = NULL; - rtp->nr--; - } - } - if (ret == NULL) - ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); - - BUG_ON(radix_tree_is_indirect_ptr(ret)); - return ret; -} - -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); - - /* - * 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); - node->slots[0] = NULL; - node->count = 0; - - kmem_cache_free(radix_tree_node_cachep, node); -} - -static inline void -radix_tree_node_free(struct radix_tree_node *node) -{ - call_rcu(&node->rcu_head, radix_tree_node_rcu_free); -} - -/* - * Load up this CPU's radix_tree_node buffer with sufficient objects to - * ensure that the addition of a single element in the tree cannot fail. On - * success, return zero, with preemption disabled. On error, return -ENOMEM - * with preemption not disabled. - */ -int radix_tree_preload(gfp_t gfp_mask) -{ - struct radix_tree_preload *rtp; - struct radix_tree_node *node; - int ret = -ENOMEM; - - preempt_disable(); - rtp = &__get_cpu_var(radix_tree_preloads); - while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { - preempt_enable(); - node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); - if (node == NULL) - goto out; - preempt_disable(); - rtp = &__get_cpu_var(radix_tree_preloads); - if (rtp->nr < ARRAY_SIZE(rtp->nodes)) - rtp->nodes[rtp->nr++] = node; - else - kmem_cache_free(radix_tree_node_cachep, node); - } - ret = 0; -out: - return ret; -} -EXPORT_SYMBOL(radix_tree_preload); - -/* - * Return the maximum key which can be store into a - * radix tree with height HEIGHT. - */ -static inline unsigned long radix_tree_maxindex(unsigned int height) -{ - return height_to_maxindex[height]; -} - -/* - * Extend a radix tree so it can store key @index. - */ -static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) -{ - struct radix_tree_node *node; - unsigned int height; - int tag; - - /* Figure out what the height should be. */ - height = root->height + 1; - while (index > radix_tree_maxindex(height)) - height++; - - if (root->rnode == NULL) { - root->height = height; - goto out; - } - - do { - unsigned int newheight; - if (!(node = radix_tree_node_alloc(root))) - return -ENOMEM; - - /* Increase the height. */ - node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); - - /* Propagate the aggregated tag info into the new root */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { - if (root_tag_get(root, tag)) - tag_set(node, tag, 0); - } - - newheight = root->height+1; - node->height = newheight; - node->count = 1; - node = radix_tree_ptr_to_indirect(node); - rcu_assign_pointer(root->rnode, node); - root->height = newheight; - } while (height > root->height); -out: - return 0; -} - -/** - * radix_tree_insert - insert into a radix tree - * @root: radix tree root - * @index: index key - * @item: item to insert - * - * Insert an item into the radix tree at position @index. - */ -int radix_tree_insert(struct radix_tree_root *root, - unsigned long index, void *item) -{ - struct radix_tree_node *node = NULL, *slot; - unsigned int height, shift; - int offset; - int error; - - BUG_ON(radix_tree_is_indirect_ptr(item)); - - /* Make sure the tree is high enough. */ - if (index > radix_tree_maxindex(root->height)) { - error = radix_tree_extend(root, index); - if (error) - return error; - } - - slot = radix_tree_indirect_to_ptr(root->rnode); - - height = root->height; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - offset = 0; /* uninitialised var warning */ - while (height > 0) { - if (slot == NULL) { - /* Have to add a child node. */ - if (!(slot = radix_tree_node_alloc(root))) - return -ENOMEM; - slot->height = height; - if (node) { - rcu_assign_pointer(node->slots[offset], slot); - node->count++; - } else - rcu_assign_pointer(root->rnode, - radix_tree_ptr_to_indirect(slot)); - } - - /* Go a level down */ - offset = (index >> shift) & RADIX_TREE_MAP_MASK; - node = slot; - slot = node->slots[offset]; - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } - - if (slot != NULL) - return -EEXIST; - - if (node) { - node->count++; - rcu_assign_pointer(node->slots[offset], item); - BUG_ON(tag_get(node, 0, offset)); - BUG_ON(tag_get(node, 1, offset)); - } else { - rcu_assign_pointer(root->rnode, item); - BUG_ON(root_tag_get(root, 0)); - BUG_ON(root_tag_get(root, 1)); - } - - return 0; -} -EXPORT_SYMBOL(radix_tree_insert); - -/** - * radix_tree_lookup_slot - lookup a slot in a radix tree - * @root: radix tree root - * @index: index key - * - * Returns: the slot corresponding to the position @index in the - * radix tree @root. This is useful for update-if-exists operations. - * - * This function can be called under rcu_read_lock iff the slot is not - * modified by radix_tree_replace_slot, otherwise it must be called - * exclusive from other writers. Any dereference of the slot must be done - * using radix_tree_deref_slot. - */ -void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) -{ - unsigned int height, shift; - struct radix_tree_node *node, **slot; - - node = rcu_dereference(root->rnode); - if (node == NULL) - return NULL; - - if (!radix_tree_is_indirect_ptr(node)) { - if (index > 0) - return NULL; - return (void **)&root->rnode; - } - node = radix_tree_indirect_to_ptr(node); - - height = node->height; - if (index > radix_tree_maxindex(height)) - return NULL; - - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - do { - slot = (struct radix_tree_node **) - (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); - node = rcu_dereference(*slot); - if (node == NULL) - return NULL; - - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } while (height > 0); - - return (void **)slot; -} -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. - * - * This function can be called under rcu_read_lock, however the caller - * must manage lifetimes of leaf nodes (eg. RCU may also be used to free - * them safely). No RCU barriers are required to access or modify the - * returned item, however. - */ -void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) -{ - unsigned int height, shift; - struct radix_tree_node *node, **slot; - - node = rcu_dereference(root->rnode); - if (node == NULL) - return NULL; - - if (!radix_tree_is_indirect_ptr(node)) { - if (index > 0) - return NULL; - return node; - } - node = radix_tree_indirect_to_ptr(node); - - height = node->height; - if (index > radix_tree_maxindex(height)) - return NULL; - - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - do { - slot = (struct radix_tree_node **) - (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); - node = rcu_dereference(*slot); - if (node == NULL) - return NULL; - - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } while (height > 0); - - return node; -} -EXPORT_SYMBOL(radix_tree_lookup); - -/** - * radix_tree_tag_set - set a tag on a radix tree node - * @root: radix tree root - * @index: index key - * @tag: tag index - * - * 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, unsigned int tag) -{ - unsigned int height, shift; - struct radix_tree_node *slot; - - height = root->height; - BUG_ON(index > radix_tree_maxindex(height)); - - slot = radix_tree_indirect_to_ptr(root->rnode); - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - - while (height > 0) { - int offset; - - offset = (index >> shift) & RADIX_TREE_MAP_MASK; - 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--; - } - - /* set the root's tag bit */ - if (slot && !root_tag_get(root, tag)) - root_tag_set(root, tag); - - return slot; -} -EXPORT_SYMBOL(radix_tree_tag_set); - -/** - * radix_tree_tag_clear - clear a tag on a radix tree node - * @root: radix tree root - * @index: index key - * @tag: tag index - * - * 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. - * - * Returns the address of the tagged item on success, else NULL. ie: - * has the same return value and semantics as radix_tree_lookup(). - */ -void *radix_tree_tag_clear(struct radix_tree_root *root, - unsigned long index, unsigned int tag) -{ - /* - * The radix tree path needs to be one longer than the maximum path - * since the "list" is null terminated. - */ - struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; - struct radix_tree_node *slot = NULL; - unsigned int height, shift; - - height = root->height; - if (index > radix_tree_maxindex(height)) - goto out; - - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - pathp->node = NULL; - slot = radix_tree_indirect_to_ptr(root->rnode); - - while (height > 0) { - int offset; - - if (slot == NULL) - goto out; - - offset = (index >> shift) & RADIX_TREE_MAP_MASK; - pathp[1].offset = offset; - pathp[1].node = slot; - slot = slot->slots[offset]; - pathp++; - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } - - if (slot == NULL) - goto out; - - while (pathp->node) { - 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--; - } - - /* clear the root's tag bit */ - if (root_tag_get(root, tag)) - root_tag_clear(root, tag); - -out: - return slot; -} -EXPORT_SYMBOL(radix_tree_tag_clear); - -#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_MAX_TAGS) - * - * Return values: - * - * 0: tag not present or not set - * 1: tag set - */ -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; - int saw_unset_tag = 0; - - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - node = rcu_dereference(root->rnode); - if (node == NULL) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) - return (index == 0); - node = radix_tree_indirect_to_ptr(node); - - height = node->height; - if (index > radix_tree_maxindex(height)) - return 0; - - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - - for ( ; ; ) { - int offset; - - if (node == 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(node, tag, offset)) - saw_unset_tag = 1; - if (height == 1) { - int ret = tag_get(node, tag, offset); - - BUG_ON(ret && saw_unset_tag); - return !!ret; - } - node = rcu_dereference(node->slots[offset]); - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } -} -EXPORT_SYMBOL(radix_tree_tag_get); -#endif - -/** - * radix_tree_next_hole - find the next hole (not-present entry) - * @root: tree root - * @index: index key - * @max_scan: maximum range to search - * - * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest - * indexed hole. - * - * Returns: the index of the hole if found, otherwise returns an index - * outside of the set specified (in which case 'return - index >= max_scan' - * will be true). In rare cases of index wrap-around, 0 will be returned. - * - * radix_tree_next_hole may be called under rcu_read_lock. However, like - * radix_tree_gang_lookup, this will not atomically search a snapshot of - * the tree at a single point in time. For example, if a hole is created - * at index 5, then subsequently a hole is created at index 10, - * radix_tree_next_hole covering both indexes may return 10 if called - * under rcu_read_lock. - */ -unsigned long radix_tree_next_hole(struct radix_tree_root *root, - unsigned long index, unsigned long max_scan) -{ - unsigned long i; - - for (i = 0; i < max_scan; i++) { - if (!radix_tree_lookup(root, index)) - break; - index++; - if (index == 0) - break; - } - - return index; -} -EXPORT_SYMBOL(radix_tree_next_hole); - -static unsigned int -__lookup(struct radix_tree_node *slot, void ***results, unsigned long index, - unsigned int max_items, unsigned long *next_index) -{ - unsigned int nr_found = 0; - unsigned int shift, height; - unsigned long i; - - height = slot->height; - if (height == 0) - goto out; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - for ( ; height > 1; height--) { - i = (index >> shift) & RADIX_TREE_MAP_MASK; - for (;;) { - if (slot->slots[i] != NULL) - break; - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - i++; - if (i == RADIX_TREE_MAP_SIZE) - goto out; - } - - shift -= RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference(slot->slots[i]); - if (slot == NULL) - goto out; - } - - /* 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; -} - -/** - * radix_tree_gang_lookup - perform multiple lookup on a radix tree - * @root: radix tree root - * @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 - * - * Performs an index-ascending scan of the tree for present items. Places - * them at *@results and returns the number of items which were placed at - * *@results. - * - * The implementation is naive. - * - * Like radix_tree_lookup, radix_tree_gang_lookup may be called under - * rcu_read_lock. In this case, rather than the returned results being - * an atomic snapshot of the tree at a single point in time, the semantics - * of an RCU protected gang lookup are as though multiple radix_tree_lookups - * have been issued in individual locks, and results stored in 'results'. - */ -unsigned int -radix_tree_gang_lookup(struct radix_tree_root *root, void **results, - unsigned long first_index, unsigned int max_items) -{ - unsigned long max_index; - struct radix_tree_node *node; - unsigned long cur_index = first_index; - unsigned int ret; - - node = rcu_dereference(root->rnode); - if (!node) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = node; - return 1; - } - node = radix_tree_indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int nr_found, slots_found, i; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup(node, (void ***)results + ret, cur_index, - max_items - ret, &next_index); - nr_found = 0; - for (i = 0; i < slots_found; i++) { - struct radix_tree_node *slot; - slot = *(((void ***)results)[ret + i]); - if (!slot) - continue; - results[ret + nr_found] = rcu_dereference(slot); - nr_found++; - } - ret += nr_found; - if (next_index == 0) - break; - cur_index = next_index; - } - - return ret; -} -EXPORT_SYMBOL(radix_tree_gang_lookup); - -/** - * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree - * @root: radix tree root - * @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 - * - * Performs an index-ascending scan of the tree for present items. Places - * their slots at *@results and returns the number of items which were - * placed at *@results. - * - * The implementation is naive. - * - * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must - * be dereferenced with radix_tree_deref_slot, and if using only RCU - * protection, radix_tree_deref_slot may fail requiring a retry. - */ -unsigned int -radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results, - unsigned long first_index, unsigned int max_items) -{ - unsigned long max_index; - struct radix_tree_node *node; - unsigned long cur_index = first_index; - unsigned int ret; - - node = rcu_dereference(root->rnode); - if (!node) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = (void **)&root->rnode; - return 1; - } - node = radix_tree_indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int slots_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup(node, results + ret, cur_index, - max_items - ret, &next_index); - ret += slots_found; - if (next_index == 0) - break; - cur_index = next_index; - } - - return ret; -} -EXPORT_SYMBOL(radix_tree_gang_lookup_slot); - -/* - * FIXME: the two tag_get()s here should use find_next_bit() instead of - * open-coding the search. - */ -static unsigned int -__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index, - unsigned int max_items, unsigned long *next_index, unsigned int tag) -{ - unsigned int nr_found = 0; - unsigned int shift, height; - - height = slot->height; - if (height == 0) - goto out; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - while (height > 0) { - unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; - - for (;;) { - if (tag_get(slot, tag, i)) - break; - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - i++; - 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 (!tag_get(slot, tag, j)) - continue; - /* - * Even though the tag was found set, we need to - * recheck that we have a non-NULL node, because - * if this lookup is lockless, it may have been - * subsequently deleted. - * - * Similar care must be taken in any place that - * lookup ->slots[x] without a lock (ie. can't - * rely on its value remaining the same). - */ - if (slot->slots[j]) { - results[nr_found++] = &(slot->slots[j]); - if (nr_found == max_items) - goto out; - } - } - } - shift -= RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference(slot->slots[i]); - if (slot == NULL) - break; - } -out: - *next_index = index; - return nr_found; -} - -/** - * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree - * based on a tag - * @root: radix tree root - * @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 (< 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 - * returns the number of items which were placed at *@results. - */ -unsigned int -radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, - unsigned long first_index, unsigned int max_items, - unsigned int tag) -{ - struct radix_tree_node *node; - unsigned long max_index; - unsigned long cur_index = first_index; - unsigned int ret; - - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - node = rcu_dereference(root->rnode); - if (!node) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = node; - return 1; - } - node = radix_tree_indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int nr_found, slots_found, i; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup_tag(node, (void ***)results + ret, - cur_index, max_items - ret, &next_index, tag); - nr_found = 0; - for (i = 0; i < slots_found; i++) { - struct radix_tree_node *slot; - slot = *(((void ***)results)[ret + i]); - if (!slot) - continue; - results[ret + nr_found] = rcu_dereference(slot); - nr_found++; - } - ret += nr_found; - if (next_index == 0) - break; - cur_index = next_index; - } - - return ret; -} -EXPORT_SYMBOL(radix_tree_gang_lookup_tag); - -/** - * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a - * radix tree based on a tag - * @root: radix tree root - * @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 (< 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 slots at *@results and - * returns the number of slots which were placed at *@results. - */ -unsigned int -radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, - unsigned long first_index, unsigned int max_items, - unsigned int tag) -{ - struct radix_tree_node *node; - unsigned long max_index; - unsigned long cur_index = first_index; - unsigned int ret; - - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - node = rcu_dereference(root->rnode); - if (!node) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = (void **)&root->rnode; - return 1; - } - node = radix_tree_indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int slots_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup_tag(node, results + ret, - cur_index, max_items - ret, &next_index, tag); - ret += slots_found; - if (next_index == 0) - break; - cur_index = next_index; - } - - return ret; -} -EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); - - -/** - * 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 > 0) { - struct radix_tree_node *to_free = root->rnode; - void *newptr; - - BUG_ON(!radix_tree_is_indirect_ptr(to_free)); - to_free = radix_tree_indirect_to_ptr(to_free); - - /* - * The candidate node has more than one child, or its child - * is not at the leftmost slot, we cannot shrink. - */ - if (to_free->count != 1) - break; - if (!to_free->slots[0]) - break; - - /* - * We don't need rcu_assign_pointer(), since we are simply - * moving the node from one part of the tree to another. If - * it was safe to dereference the old pointer to it - * (to_free->slots[0]), it will be safe to dereference the new - * one (root->rnode). - */ - newptr = to_free->slots[0]; - if (root->height > 1) - newptr = radix_tree_ptr_to_indirect(newptr); - root->rnode = newptr; - root->height--; - radix_tree_node_free(to_free); - } -} - -/** - * radix_tree_delete - delete an item from a radix tree - * @root: radix tree root - * @index: index key - * - * Remove the item at @index from the radix tree rooted at @root. - * - * Returns the address of the deleted item, or NULL if it was not present. - */ -void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) -{ - /* - * The radix tree path needs to be one longer than the maximum path - * since the "list" is null terminated. - */ - struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; - struct radix_tree_node *slot = NULL; - struct radix_tree_node *to_free; - unsigned int height, shift; - int tag; - int offset; - - height = root->height; - if (index > radix_tree_maxindex(height)) - goto out; - - slot = root->rnode; - if (height == 0) { - root_tag_clear_all(root); - root->rnode = NULL; - goto out; - } - slot = radix_tree_indirect_to_ptr(slot); - - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - pathp->node = NULL; - - do { - if (slot == NULL) - goto out; - - pathp++; - offset = (index >> shift) & RADIX_TREE_MAP_MASK; - pathp->offset = offset; - pathp->node = slot; - slot = slot->slots[offset]; - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } while (height > 0); - - if (slot == NULL) - goto out; - - /* - * Clear all tags associated with the just-deleted item - */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { - if (tag_get(pathp->node, tag, pathp->offset)) - radix_tree_tag_clear(root, index, tag); - } - - to_free = NULL; - /* Now free the nodes we do not need anymore */ - while (pathp->node) { - pathp->node->slots[pathp->offset] = NULL; - pathp->node->count--; - /* - * Queue the node for deferred freeing after the - * last reference to it disappears (set NULL, above). - */ - if (to_free) - radix_tree_node_free(to_free); - - if (pathp->node->count) { - if (pathp->node == - radix_tree_indirect_to_ptr(root->rnode)) - radix_tree_shrink(root); - goto out; - } - - /* Node with zero slots in use so free it */ - to_free = pathp->node; - pathp--; - - } - root_tag_clear_all(root); - root->height = 0; - root->rnode = NULL; - if (to_free) - radix_tree_node_free(to_free); - -out: - return slot; -} -EXPORT_SYMBOL(radix_tree_delete); - -/** - * radix_tree_tagged - test whether any items in the tree are tagged - * @root: radix tree root - * @tag: tag to test - */ -int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) -{ - return root_tag_get(root, tag); -} -EXPORT_SYMBOL(radix_tree_tagged); - -static void -radix_tree_node_ctor(void *node) -{ - memset(node, 0, sizeof(struct radix_tree_node)); -} - -static __init unsigned long __maxindex(unsigned int height) -{ - unsigned int width = height * RADIX_TREE_MAP_SHIFT; - int shift = RADIX_TREE_INDEX_BITS - width; - - if (shift < 0) - return ~0UL; - if (shift >= BITS_PER_LONG) - return 0UL; - return ~0UL >> shift; -} - -static __init void radix_tree_init_maxindex(void) -{ - unsigned int i; - - for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) - height_to_maxindex[i] = __maxindex(i); -} - -static int radix_tree_callback(struct notifier_block *nfb, - unsigned long action, - void *hcpu) -{ - int cpu = (long)hcpu; - struct radix_tree_preload *rtp; - - /* Free per-cpu pool of perloaded nodes */ - if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { - rtp = &per_cpu(radix_tree_preloads, cpu); - while (rtp->nr) { - kmem_cache_free(radix_tree_node_cachep, - rtp->nodes[rtp->nr-1]); - rtp->nodes[rtp->nr-1] = NULL; - rtp->nr--; - } - } - return NOTIFY_OK; -} - -void __init radix_tree_init(void) -{ - radix_tree_node_cachep = kmem_cache_create("radix_tree_node", - sizeof(struct radix_tree_node), 0, - SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, - radix_tree_node_ctor); - radix_tree_init_maxindex(); - hotcpu_notifier(radix_tree_callback, 0); -} |