diff options
Diffstat (limited to 'fs/btrfs/radix-tree.c')
| -rw-r--r-- | fs/btrfs/radix-tree.c | 836 |
1 files changed, 0 insertions, 836 deletions
diff --git a/fs/btrfs/radix-tree.c b/fs/btrfs/radix-tree.c deleted file mode 100644 index baa25ca..0000000 --- a/fs/btrfs/radix-tree.c +++ /dev/null @@ -1,836 +0,0 @@ -/* - * 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 - * 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 "kerncompat.h" -#include "radix-tree.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 count; - 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 (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) - -static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; - -/* - * Per-cpu pool of preloaded nodes - */ -struct radix_tree_preload { - int nr; - struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; -}; -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 int internal_nodes = 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; - ret = malloc(sizeof(struct radix_tree_node)); - if (ret) { - memset(ret, 0, sizeof(struct radix_tree_node)); - internal_nodes++; - } - return ret; -} - -static inline void -radix_tree_node_free(struct radix_tree_node *node) -{ - internal_nodes--; - free(node); -} - -/* - * 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 = radix_tree_node_alloc(NULL); - 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 - radix_tree_node_free(node); - } - ret = 0; -out: - return ret; -} - -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; -} - -/* - * 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 { - if (!(node = radix_tree_node_alloc(root))) - return -ENOMEM; - - /* Increase the height. */ - node->slots[0] = 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); - } - - node->count = 1; - root->rnode = node; - root->height++; - } 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; - - /* 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 = 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; - 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 = node->slots[offset]; - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } - - if (slot != NULL) - return -EEXIST; - - if (node) { - node->count++; - node->slots[offset] = item; - BUG_ON(tag_get(node, 0, offset)); - BUG_ON(tag_get(node, 1, offset)); - } else { - root->rnode = item; - BUG_ON(root_tag_get(root, 0)); - BUG_ON(root_tag_get(root, 1)); - } - - return 0; -} - -static inline void **__lookup_slot(struct radix_tree_root *root, - unsigned long index) -{ - unsigned int height, shift; - struct radix_tree_node **slot; - - height = root->height; - - if (index > radix_tree_maxindex(height)) - return NULL; - - if (height == 0 && root->rnode) - return (void **)&root->rnode; - - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - slot = &root->rnode; - - while (height > 0) { - if (*slot == NULL) - return NULL; - - slot = (struct radix_tree_node **) - ((*slot)->slots + - ((index >> shift) & RADIX_TREE_MAP_MASK)); - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } - - 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); -} - -/** - * 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; -} - -/** - * 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 = 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; -} - -/** - * 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) -{ - struct radix_tree_path path[RADIX_TREE_MAX_PATH], *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 = 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; -} - -#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 *slot; - int saw_unset_tag = 0; - - height = root->height; - if (index > radix_tree_maxindex(height)) - return 0; - - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - if (height == 0) - return 1; - - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - slot = root->rnode; - - for ( ; ; ) { - int offset; - - 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)) - saw_unset_tag = 1; - if (height == 1) { - int ret = tag_get(slot, tag, offset); - - BUG_ON(ret && saw_unset_tag); - return !!ret; - } - slot = slot->slots[offset]; - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } -} -#endif - -static unsigned int -__lookup(struct radix_tree_root *root, void **results, unsigned long index, - unsigned int max_items, unsigned long *next_index) -{ - unsigned int nr_found = 0; - unsigned int shift, height; - struct radix_tree_node *slot; - unsigned long i; - - height = root->height; - if (height == 0) { - if (root->rnode && index == 0) - results[nr_found++] = root->rnode; - goto out; - } - - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - slot = root->rnode; - - for ( ; height > 1; height--) { - - for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; - i < RADIX_TREE_MAP_SIZE; i++) { - if (slot->slots[i] != NULL) - break; - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - } - if (i == RADIX_TREE_MAP_SIZE) - 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; -} - -/** - * 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. - */ -unsigned int -radix_tree_gang_lookup(struct radix_tree_root *root, void **results, - unsigned long first_index, unsigned int max_items) -{ - const unsigned long max_index = radix_tree_maxindex(root->height); - unsigned long cur_index = first_index; - unsigned int ret = 0; - - while (ret < max_items) { - unsigned int nr_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - nr_found = __lookup(root, results + ret, cur_index, - max_items - ret, &next_index); - ret += nr_found; - if (next_index == 0) - break; - cur_index = next_index; - } - return ret; -} - -/* - * 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_root *root, void **results, unsigned long index, - unsigned int max_items, unsigned long *next_index, unsigned int tag) -{ - unsigned int nr_found = 0; - unsigned int shift; - unsigned int height = root->height; - struct radix_tree_node *slot; - - if (height == 0) { - if (root->rnode && index == 0) - results[nr_found++] = root->rnode; - goto out; - } - - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; - slot = root->rnode; - - do { - unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; - - for ( ; i < RADIX_TREE_MAP_SIZE; i++) { - if (tag_get(slot, tag, i)) { - BUG_ON(slot->slots[i] == NULL); - break; - } - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - } - 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)) { - BUG_ON(slot->slots[j] == NULL); - results[nr_found++] = slot->slots[j]; - if (nr_found == max_items) - goto out; - } - } - } - shift -= RADIX_TREE_MAP_SHIFT; - slot = slot->slots[i]; - } while (height > 0); -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) -{ - const unsigned long max_index = radix_tree_maxindex(root->height); - unsigned long cur_index = first_index; - unsigned int ret = 0; - - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - while (ret < max_items) { - unsigned int nr_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - nr_found = __lookup_tag(root, results + ret, cur_index, - max_items - ret, &next_index, tag); - ret += nr_found; - if (next_index == 0) - break; - cur_index = next_index; - } - return ret; -} - -/** - * 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 && - 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 - * @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) -{ - struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; - struct radix_tree_node *slot = NULL; - 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->rnode) { - root_tag_clear_all(root); - root->rnode = NULL; - goto out; - } - - 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); - } - - /* Now free the nodes we do not need anymore */ - while (pathp->node) { - 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); - - pathp--; - } - root_tag_clear_all(root); - root->height = 0; - root->rnode = NULL; - -out: - return slot; -} - -/** - * 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); -} - -static unsigned long __maxindex(unsigned int height) -{ - unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; - unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; - - if (tmp >= RADIX_TREE_INDEX_BITS) - index = ~0UL; - return index; -} - -static 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); -} - -void radix_tree_init(void) -{ - radix_tree_init_maxindex(); -} |
