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lib/radix-tree.c
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/* * Copyright (C) 2001 Momchil Velikov * Portions Copyright (C) 2001 Christoph Hellwig |
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* Copyright (C) 2005 SGI, Christoph Lameter |
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* Copyright (C) 2006 Nick Piggin |
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* * 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> |
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#include <linux/string.h> #include <linux/bitops.h> |
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#include <linux/rcupdate.h> |
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#ifdef __KERNEL__ |
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#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
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#else #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ #endif |
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#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 { |
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unsigned int height; /* Height from the bottom */ |
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unsigned int count; |
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struct rcu_head rcu_head; |
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void __rcu *slots[RADIX_TREE_MAP_SIZE]; |
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unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
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}; struct radix_tree_path { |
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struct radix_tree_node *node; |
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int offset; }; #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) |
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#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ RADIX_TREE_MAP_SHIFT)) |
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|
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/* * 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; |
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/* * Radix tree node cache. */ |
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static struct kmem_cache *radix_tree_node_cachep; |
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/* * Per-cpu pool of preloaded nodes */ struct radix_tree_preload { int nr; struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; }; |
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static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
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|
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static inline void *ptr_to_indirect(void *ptr) { return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR); } static inline void *indirect_to_ptr(void *ptr) { return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); } |
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static inline gfp_t root_gfp_mask(struct radix_tree_root *root) { return root->gfp_mask & __GFP_BITS_MASK; } |
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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; } |
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/* * 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) { |
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struct radix_tree_node *ret = NULL; |
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gfp_t gfp_mask = root_gfp_mask(root); |
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|
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if (!(gfp_mask & __GFP_WAIT)) { |
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struct radix_tree_preload *rtp; |
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/* * Provided the caller has preloaded here, we will always * succeed in getting a node here (and never reach * kmem_cache_alloc) */ |
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rtp = &__get_cpu_var(radix_tree_preloads); if (rtp->nr) { ret = rtp->nodes[rtp->nr - 1]; rtp->nodes[rtp->nr - 1] = NULL; rtp->nr--; } } |
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if (ret == NULL) |
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ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
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|
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BUG_ON(radix_tree_is_indirect_ptr(ret)); |
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return ret; } |
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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); |
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int i; |
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/* * 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. */ |
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for (i = 0; i < RADIX_TREE_MAX_TAGS; i++) tag_clear(node, i, 0); |
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node->slots[0] = NULL; node->count = 0; |
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kmem_cache_free(radix_tree_node_cachep, node); } |
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static inline void radix_tree_node_free(struct radix_tree_node *node) { |
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call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
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} /* * 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. |
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* * To make use of this facility, the radix tree must be initialised without * __GFP_WAIT being passed to INIT_RADIX_TREE(). |
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*/ |
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int radix_tree_preload(gfp_t gfp_mask) |
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{ 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(); |
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node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
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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; } |
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EXPORT_SYMBOL(radix_tree_preload); |
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|
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/* |
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* 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; |
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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; } |
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do { |
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unsigned int newheight; |
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if (!(node = radix_tree_node_alloc(root))) return -ENOMEM; /* Increase the height. */ |
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node->slots[0] = indirect_to_ptr(root->rnode); |
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/* Propagate the aggregated tag info into the new root */ |
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for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
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if (root_tag_get(root, tag)) |
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tag_set(node, tag, 0); } |
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newheight = root->height+1; node->height = newheight; |
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node->count = 1; |
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node = ptr_to_indirect(node); |
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rcu_assign_pointer(root->rnode, node); root->height = newheight; |
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} 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) { |
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struct radix_tree_node *node = NULL, *slot; |
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unsigned int height, shift; int offset; int error; |
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BUG_ON(radix_tree_is_indirect_ptr(item)); |
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|
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/* Make sure the tree is high enough. */ |
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if (index > radix_tree_maxindex(root->height)) { |
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error = radix_tree_extend(root, index); if (error) return error; } |
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slot = indirect_to_ptr(root->rnode); |
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|
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height = root->height; shift = (height-1) * RADIX_TREE_MAP_SHIFT; offset = 0; /* uninitialised var warning */ |
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while (height > 0) { |
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if (slot == NULL) { |
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/* Have to add a child node. */ |
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if (!(slot = radix_tree_node_alloc(root))) |
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return -ENOMEM; |
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slot->height = height; |
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if (node) { |
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rcu_assign_pointer(node->slots[offset], slot); |
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node->count++; |
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} else |
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rcu_assign_pointer(root->rnode, ptr_to_indirect(slot)); |
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} /* Go a level down */ offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
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node = slot; slot = node->slots[offset]; |
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shift -= RADIX_TREE_MAP_SHIFT; height--; |
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} |
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|
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if (slot != NULL) |
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return -EEXIST; |
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|
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if (node) { node->count++; |
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rcu_assign_pointer(node->slots[offset], item); |
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BUG_ON(tag_get(node, 0, offset)); BUG_ON(tag_get(node, 1, offset)); } else { |
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rcu_assign_pointer(root->rnode, item); |
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BUG_ON(root_tag_get(root, 0)); BUG_ON(root_tag_get(root, 1)); } |
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return 0; } EXPORT_SYMBOL(radix_tree_insert); |
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/* * is_slot == 1 : search for the slot. * is_slot == 0 : search for the node. |
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*/ |
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static void *radix_tree_lookup_element(struct radix_tree_root *root, unsigned long index, int is_slot) |
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{ unsigned int height, shift; |
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struct radix_tree_node *node, **slot; |
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|
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node = rcu_dereference_raw(root->rnode); |
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if (node == NULL) |
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return NULL; |
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if (!radix_tree_is_indirect_ptr(node)) { |
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if (index > 0) return NULL; |
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return is_slot ? (void *)&root->rnode : node; |
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} |
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node = indirect_to_ptr(node); |
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height = node->height; if (index > radix_tree_maxindex(height)) return NULL; |
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|
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shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
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|
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do { slot = (struct radix_tree_node **) (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); |
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node = rcu_dereference_raw(*slot); |
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if (node == NULL) |
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return NULL; |
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shift -= RADIX_TREE_MAP_SHIFT; height--; |
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} while (height > 0); |
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|
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return is_slot ? (void *)slot : indirect_to_ptr(node); |
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} /** * 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) { return (void **)radix_tree_lookup_element(root, index, 1); |
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} |
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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. |
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* * 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. |
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*/ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) { |
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return radix_tree_lookup_element(root, index, 0); |
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} 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 * |
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* Set the search tag (which must be < RADIX_TREE_MAX_TAGS) * corresponding to @index in the radix tree. From |
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* 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, |
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unsigned long index, unsigned int tag) |
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{ unsigned int height, shift; |
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struct radix_tree_node *slot; |
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height = root->height; |
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BUG_ON(index > radix_tree_maxindex(height)); |
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|
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slot = indirect_to_ptr(root->rnode); |
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shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
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while (height > 0) { int offset; offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
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if (!tag_get(slot, tag, offset)) tag_set(slot, tag, offset); |
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slot = slot->slots[offset]; BUG_ON(slot == NULL); |
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shift -= RADIX_TREE_MAP_SHIFT; height--; } |
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467 468 469 |
/* set the root's tag bit */ if (slot && !root_tag_get(root, tag)) root_tag_set(root, tag); |
201b6264f [PATCH] radix-tre... |
470 |
return slot; |
1da177e4c Linux-2.6.12-rc2 |
471 472 473 474 475 476 477 478 479 |
} 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 * |
daff89f32 [PATCH] radix-tre... |
480 481 |
* Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) * corresponding to @index in the radix tree. If |
1da177e4c Linux-2.6.12-rc2 |
482 483 484 485 486 487 488 |
* 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, |
daff89f32 [PATCH] radix-tre... |
489 |
unsigned long index, unsigned int tag) |
1da177e4c Linux-2.6.12-rc2 |
490 |
{ |
26fb1589c fix the max path ... |
491 492 493 494 495 |
/* * 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; |
612d6c19d [PATCH] radix-tre... |
496 |
struct radix_tree_node *slot = NULL; |
1da177e4c Linux-2.6.12-rc2 |
497 |
unsigned int height, shift; |
1da177e4c Linux-2.6.12-rc2 |
498 499 500 501 502 503 504 |
height = root->height; if (index > radix_tree_maxindex(height)) goto out; shift = (height - 1) * RADIX_TREE_MAP_SHIFT; pathp->node = NULL; |
27d20fddc radix-tree: fix R... |
505 |
slot = indirect_to_ptr(root->rnode); |
1da177e4c Linux-2.6.12-rc2 |
506 507 508 |
while (height > 0) { int offset; |
201b6264f [PATCH] radix-tre... |
509 |
if (slot == NULL) |
1da177e4c Linux-2.6.12-rc2 |
510 511 512 513 |
goto out; offset = (index >> shift) & RADIX_TREE_MAP_MASK; pathp[1].offset = offset; |
201b6264f [PATCH] radix-tre... |
514 515 |
pathp[1].node = slot; slot = slot->slots[offset]; |
1da177e4c Linux-2.6.12-rc2 |
516 517 518 519 |
pathp++; shift -= RADIX_TREE_MAP_SHIFT; height--; } |
612d6c19d [PATCH] radix-tre... |
520 |
if (slot == NULL) |
1da177e4c Linux-2.6.12-rc2 |
521 |
goto out; |
612d6c19d [PATCH] radix-tre... |
522 |
while (pathp->node) { |
d5274261e [PATCH] radix tre... |
523 524 |
if (!tag_get(pathp->node, tag, pathp->offset)) goto out; |
201b6264f [PATCH] radix-tre... |
525 |
tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e9 [PATCH] radix tre... |
526 527 |
if (any_tag_set(pathp->node, tag)) goto out; |
1da177e4c Linux-2.6.12-rc2 |
528 |
pathp--; |
612d6c19d [PATCH] radix-tre... |
529 530 531 532 533 |
} /* clear the root's tag bit */ if (root_tag_get(root, tag)) root_tag_clear(root, tag); |
1da177e4c Linux-2.6.12-rc2 |
534 |
out: |
612d6c19d [PATCH] radix-tre... |
535 |
return slot; |
1da177e4c Linux-2.6.12-rc2 |
536 537 |
} EXPORT_SYMBOL(radix_tree_tag_clear); |
1da177e4c Linux-2.6.12-rc2 |
538 |
/** |
32605a181 [PATCH] radix_tag... |
539 540 541 |
* radix_tree_tag_get - get a tag on a radix tree node * @root: radix tree root * @index: index key |
daff89f32 [PATCH] radix-tre... |
542 |
* @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4c Linux-2.6.12-rc2 |
543 |
* |
32605a181 [PATCH] radix_tag... |
544 |
* Return values: |
1da177e4c Linux-2.6.12-rc2 |
545 |
* |
612d6c19d [PATCH] radix-tre... |
546 547 |
* 0: tag not present or not set * 1: tag set |
ce82653d6 radix_tree_tag_ge... |
548 549 550 551 |
* * Note that the return value of this function may not be relied on, even if * the RCU lock is held, unless tag modification and node deletion are excluded * from concurrency. |
1da177e4c Linux-2.6.12-rc2 |
552 553 |
*/ int radix_tree_tag_get(struct radix_tree_root *root, |
daff89f32 [PATCH] radix-tre... |
554 |
unsigned long index, unsigned int tag) |
1da177e4c Linux-2.6.12-rc2 |
555 556 |
{ unsigned int height, shift; |
7cf9c2c76 [PATCH] radix-tre... |
557 |
struct radix_tree_node *node; |
1da177e4c Linux-2.6.12-rc2 |
558 |
int saw_unset_tag = 0; |
612d6c19d [PATCH] radix-tre... |
559 560 561 |
/* check the root's tag bit */ if (!root_tag_get(root, tag)) return 0; |
2676a58c9 radix-tree: Disab... |
562 |
node = rcu_dereference_raw(root->rnode); |
7cf9c2c76 [PATCH] radix-tre... |
563 564 |
if (node == NULL) return 0; |
c0bc9875b radix-tree: use i... |
565 |
if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c76 [PATCH] radix-tre... |
566 |
return (index == 0); |
27d20fddc radix-tree: fix R... |
567 |
node = indirect_to_ptr(node); |
7cf9c2c76 [PATCH] radix-tre... |
568 569 570 571 |
height = node->height; if (index > radix_tree_maxindex(height)) return 0; |
612d6c19d [PATCH] radix-tre... |
572 |
|
1da177e4c Linux-2.6.12-rc2 |
573 |
shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4c Linux-2.6.12-rc2 |
574 575 576 |
for ( ; ; ) { int offset; |
7cf9c2c76 [PATCH] radix-tre... |
577 |
if (node == NULL) |
1da177e4c Linux-2.6.12-rc2 |
578 579 580 581 582 583 584 585 |
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. */ |
7cf9c2c76 [PATCH] radix-tre... |
586 |
if (!tag_get(node, tag, offset)) |
1da177e4c Linux-2.6.12-rc2 |
587 |
saw_unset_tag = 1; |
ce82653d6 radix_tree_tag_ge... |
588 589 |
if (height == 1) return !!tag_get(node, tag, offset); |
2676a58c9 radix-tree: Disab... |
590 |
node = rcu_dereference_raw(node->slots[offset]); |
1da177e4c Linux-2.6.12-rc2 |
591 592 593 594 595 |
shift -= RADIX_TREE_MAP_SHIFT; height--; } } EXPORT_SYMBOL(radix_tree_tag_get); |
1da177e4c Linux-2.6.12-rc2 |
596 |
|
6df8ba4f8 radixtree: introd... |
597 |
/** |
ebf8aa44b radix-tree: omple... |
598 599 600 601 602 603 604 605 606 607 608 609 610 611 |
* radix_tree_range_tag_if_tagged - for each item in given range set given * tag if item has another tag set * @root: radix tree root * @first_indexp: pointer to a starting index of a range to scan * @last_index: last index of a range to scan * @nr_to_tag: maximum number items to tag * @iftag: tag index to test * @settag: tag index to set if tested tag is set * * This function scans range of radix tree from first_index to last_index * (inclusive). For each item in the range if iftag is set, the function sets * also settag. The function stops either after tagging nr_to_tag items or * after reaching last_index. * |
144dcfc01 radix-tree: radix... |
612 613 614 615 616 617 618 |
* The tags must be set from the leaf level only and propagated back up the * path to the root. We must do this so that we resolve the full path before * setting any tags on intermediate nodes. If we set tags as we descend, then * we can get to the leaf node and find that the index that has the iftag * set is outside the range we are scanning. This reults in dangling tags and * can lead to problems with later tag operations (e.g. livelocks on lookups). * |
ebf8aa44b radix-tree: omple... |
619 620 |
* The function returns number of leaves where the tag was set and sets * *first_indexp to the first unscanned index. |
d5ed3a4af lib/radix-tree.c:... |
621 622 |
* WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must * be prepared to handle that. |
ebf8aa44b radix-tree: omple... |
623 624 625 626 627 628 |
*/ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, unsigned long *first_indexp, unsigned long last_index, unsigned long nr_to_tag, unsigned int iftag, unsigned int settag) { |
144dcfc01 radix-tree: radix... |
629 630 631 632 633 634 635 |
unsigned int height = root->height; struct radix_tree_path path[height]; struct radix_tree_path *pathp = path; struct radix_tree_node *slot; unsigned int shift; unsigned long tagged = 0; unsigned long index = *first_indexp; |
ebf8aa44b radix-tree: omple... |
636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 |
last_index = min(last_index, radix_tree_maxindex(height)); if (index > last_index) return 0; if (!nr_to_tag) return 0; if (!root_tag_get(root, iftag)) { *first_indexp = last_index + 1; return 0; } if (height == 0) { *first_indexp = last_index + 1; root_tag_set(root, settag); return 1; } shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
27d20fddc radix-tree: fix R... |
653 |
slot = indirect_to_ptr(root->rnode); |
ebf8aa44b radix-tree: omple... |
654 |
|
144dcfc01 radix-tree: radix... |
655 656 657 658 659 660 |
/* * we fill the path from (root->height - 2) to 0, leaving the index at * (root->height - 1) as a terminator. Zero the node in the terminator * so that we can use this to end walk loops back up the path. */ path[height - 1].node = NULL; |
ebf8aa44b radix-tree: omple... |
661 662 663 664 665 666 667 668 |
for (;;) { int offset; offset = (index >> shift) & RADIX_TREE_MAP_MASK; if (!slot->slots[offset]) goto next; if (!tag_get(slot, iftag, offset)) goto next; |
144dcfc01 radix-tree: radix... |
669 670 671 672 673 674 675 676 677 678 679 680 |
if (height > 1) { /* Go down one level */ height--; shift -= RADIX_TREE_MAP_SHIFT; path[height - 1].node = slot; path[height - 1].offset = offset; slot = slot->slots[offset]; continue; } /* tag the leaf */ tagged++; |
ebf8aa44b radix-tree: omple... |
681 |
tag_set(slot, settag, offset); |
144dcfc01 radix-tree: radix... |
682 683 684 685 686 687 688 689 690 |
/* walk back up the path tagging interior nodes */ pathp = &path[0]; while (pathp->node) { /* stop if we find a node with the tag already set */ if (tag_get(pathp->node, settag, pathp->offset)) break; tag_set(pathp->node, settag, pathp->offset); pathp++; |
ebf8aa44b radix-tree: omple... |
691 |
} |
144dcfc01 radix-tree: radix... |
692 |
|
ebf8aa44b radix-tree: omple... |
693 694 695 |
next: /* Go to next item at level determined by 'shift' */ index = ((index >> shift) + 1) << shift; |
d5ed3a4af lib/radix-tree.c:... |
696 697 |
/* Overflow can happen when last_index is ~0UL... */ if (index > last_index || !index) |
ebf8aa44b radix-tree: omple... |
698 699 700 701 702 703 704 705 706 |
break; if (tagged >= nr_to_tag) break; while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) { /* * We've fully scanned this node. Go up. Because * last_index is guaranteed to be in the tree, what * we do below cannot wander astray. */ |
144dcfc01 radix-tree: radix... |
707 |
slot = path[height - 1].node; |
ebf8aa44b radix-tree: omple... |
708 709 710 711 712 |
height++; shift += RADIX_TREE_MAP_SHIFT; } } /* |
ac15ee691 radix_tree: radix... |
713 714 |
* We need not to tag the root tag if there is no tag which is set with * settag within the range from *first_indexp to last_index. |
ebf8aa44b radix-tree: omple... |
715 |
*/ |
ac15ee691 radix_tree: radix... |
716 717 |
if (tagged > 0) root_tag_set(root, settag); |
ebf8aa44b radix-tree: omple... |
718 719 720 721 722 723 724 725 |
*first_indexp = index; return tagged; } EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); /** |
6df8ba4f8 radixtree: introd... |
726 727 728 729 730 731 732 733 734 735 |
* 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' |
8e6bdb7f8 trivial: radix-tr... |
736 |
* will be true). In rare cases of index wrap-around, 0 will be returned. |
6df8ba4f8 radixtree: introd... |
737 738 |
* * radix_tree_next_hole may be called under rcu_read_lock. However, like |
8e6bdb7f8 trivial: radix-tr... |
739 740 741 742 743 |
* 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. |
6df8ba4f8 radixtree: introd... |
744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 |
*/ 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); |
dc566127d radix-tree: add r... |
761 762 763 764 765 766 767 768 769 770 771 |
/** * radix_tree_prev_hole - find the prev hole (not-present entry) * @root: tree root * @index: index key * @max_scan: maximum range to search * * Search backwards in the range [max(index-max_scan+1, 0), index] * for the first hole. * * Returns: the index of the hole if found, otherwise returns an index * outside of the set specified (in which case 'index - return >= max_scan' |
edcd1d843 radix-tree: fix r... |
772 |
* will be true). In rare cases of wrap-around, ULONG_MAX will be returned. |
dc566127d radix-tree: add r... |
773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 |
* * 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 10, then subsequently a hole is created at index 5, * radix_tree_prev_hole covering both indexes may return 5 if called under * rcu_read_lock. */ unsigned long radix_tree_prev_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--; |
edcd1d843 radix-tree: fix r... |
790 |
if (index == ULONG_MAX) |
dc566127d radix-tree: add r... |
791 792 793 794 795 796 |
break; } return index; } EXPORT_SYMBOL(radix_tree_prev_hole); |
1da177e4c Linux-2.6.12-rc2 |
797 |
static unsigned int |
47feff2c8 radix-tree: add g... |
798 |
__lookup(struct radix_tree_node *slot, void ***results, unsigned long index, |
1da177e4c Linux-2.6.12-rc2 |
799 800 801 |
unsigned int max_items, unsigned long *next_index) { unsigned int nr_found = 0; |
201b6264f [PATCH] radix-tre... |
802 |
unsigned int shift, height; |
201b6264f [PATCH] radix-tre... |
803 |
unsigned long i; |
7cf9c2c76 [PATCH] radix-tre... |
804 805 |
height = slot->height; if (height == 0) |
201b6264f [PATCH] radix-tre... |
806 |
goto out; |
1da177e4c Linux-2.6.12-rc2 |
807 |
shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4c Linux-2.6.12-rc2 |
808 |
|
201b6264f [PATCH] radix-tre... |
809 |
for ( ; height > 1; height--) { |
7cf9c2c76 [PATCH] radix-tre... |
810 811 |
i = (index >> shift) & RADIX_TREE_MAP_MASK; for (;;) { |
1da177e4c Linux-2.6.12-rc2 |
812 813 814 815 816 817 |
if (slot->slots[i] != NULL) break; index &= ~((1UL << shift) - 1); index += 1UL << shift; if (index == 0) goto out; /* 32-bit wraparound */ |
7cf9c2c76 [PATCH] radix-tre... |
818 819 820 |
i++; if (i == RADIX_TREE_MAP_SIZE) goto out; |
1da177e4c Linux-2.6.12-rc2 |
821 |
} |
1da177e4c Linux-2.6.12-rc2 |
822 |
|
1da177e4c Linux-2.6.12-rc2 |
823 |
shift -= RADIX_TREE_MAP_SHIFT; |
2676a58c9 radix-tree: Disab... |
824 |
slot = rcu_dereference_raw(slot->slots[i]); |
7cf9c2c76 [PATCH] radix-tre... |
825 826 |
if (slot == NULL) goto out; |
1da177e4c Linux-2.6.12-rc2 |
827 |
} |
201b6264f [PATCH] radix-tre... |
828 829 830 831 |
/* Bottom level: grab some items */ for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { index++; |
47feff2c8 radix-tree: add g... |
832 833 |
if (slot->slots[i]) { results[nr_found++] = &(slot->slots[i]); |
201b6264f [PATCH] radix-tre... |
834 835 836 837 |
if (nr_found == max_items) goto out; } } |
1da177e4c Linux-2.6.12-rc2 |
838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 |
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. |
7cf9c2c76 [PATCH] radix-tre... |
855 856 857 858 859 860 |
* * 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'. |
1da177e4c Linux-2.6.12-rc2 |
861 862 863 864 865 |
*/ unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items) { |
7cf9c2c76 [PATCH] radix-tre... |
866 867 |
unsigned long max_index; struct radix_tree_node *node; |
1da177e4c Linux-2.6.12-rc2 |
868 |
unsigned long cur_index = first_index; |
7cf9c2c76 [PATCH] radix-tre... |
869 |
unsigned int ret; |
2676a58c9 radix-tree: Disab... |
870 |
node = rcu_dereference_raw(root->rnode); |
7cf9c2c76 [PATCH] radix-tre... |
871 872 |
if (!node) return 0; |
1da177e4c Linux-2.6.12-rc2 |
873 |
|
c0bc9875b radix-tree: use i... |
874 |
if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c76 [PATCH] radix-tre... |
875 876 |
if (first_index > 0) return 0; |
c0bc9875b radix-tree: use i... |
877 |
results[0] = node; |
7cf9c2c76 [PATCH] radix-tre... |
878 879 |
return 1; } |
27d20fddc radix-tree: fix R... |
880 |
node = indirect_to_ptr(node); |
7cf9c2c76 [PATCH] radix-tre... |
881 882 883 884 |
max_index = radix_tree_maxindex(node->height); ret = 0; |
1da177e4c Linux-2.6.12-rc2 |
885 |
while (ret < max_items) { |
47feff2c8 radix-tree: add g... |
886 |
unsigned int nr_found, slots_found, i; |
1da177e4c Linux-2.6.12-rc2 |
887 888 889 890 |
unsigned long next_index; /* Index of next search */ if (cur_index > max_index) break; |
47feff2c8 radix-tree: add g... |
891 |
slots_found = __lookup(node, (void ***)results + ret, cur_index, |
1da177e4c Linux-2.6.12-rc2 |
892 |
max_items - ret, &next_index); |
47feff2c8 radix-tree: add g... |
893 894 895 896 897 898 |
nr_found = 0; for (i = 0; i < slots_found; i++) { struct radix_tree_node *slot; slot = *(((void ***)results)[ret + i]); if (!slot) continue; |
27d20fddc radix-tree: fix R... |
899 900 |
results[ret + nr_found] = indirect_to_ptr(rcu_dereference_raw(slot)); |
47feff2c8 radix-tree: add g... |
901 902 |
nr_found++; } |
1da177e4c Linux-2.6.12-rc2 |
903 904 905 906 907 |
ret += nr_found; if (next_index == 0) break; cur_index = next_index; } |
7cf9c2c76 [PATCH] radix-tre... |
908 |
|
1da177e4c Linux-2.6.12-rc2 |
909 910 911 |
return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup); |
47feff2c8 radix-tree: add g... |
912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 |
/** * 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; |
2676a58c9 radix-tree: Disab... |
937 |
node = rcu_dereference_raw(root->rnode); |
47feff2c8 radix-tree: add g... |
938 939 940 941 942 943 944 945 946 |
if (!node) return 0; if (!radix_tree_is_indirect_ptr(node)) { if (first_index > 0) return 0; results[0] = (void **)&root->rnode; return 1; } |
27d20fddc radix-tree: fix R... |
947 |
node = indirect_to_ptr(node); |
47feff2c8 radix-tree: add g... |
948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 |
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); |
1da177e4c Linux-2.6.12-rc2 |
969 970 971 972 973 |
/* * FIXME: the two tag_get()s here should use find_next_bit() instead of * open-coding the search. */ static unsigned int |
47feff2c8 radix-tree: add g... |
974 |
__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index, |
daff89f32 [PATCH] radix-tre... |
975 |
unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4c Linux-2.6.12-rc2 |
976 977 |
{ unsigned int nr_found = 0; |
7cf9c2c76 [PATCH] radix-tre... |
978 |
unsigned int shift, height; |
1da177e4c Linux-2.6.12-rc2 |
979 |
|
7cf9c2c76 [PATCH] radix-tre... |
980 981 |
height = slot->height; if (height == 0) |
612d6c19d [PATCH] radix-tre... |
982 |
goto out; |
7cf9c2c76 [PATCH] radix-tre... |
983 |
shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4c Linux-2.6.12-rc2 |
984 |
|
7cf9c2c76 [PATCH] radix-tre... |
985 986 |
while (height > 0) { unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; |
1da177e4c Linux-2.6.12-rc2 |
987 |
|
7cf9c2c76 [PATCH] radix-tre... |
988 989 |
for (;;) { if (tag_get(slot, tag, i)) |
1da177e4c Linux-2.6.12-rc2 |
990 |
break; |
1da177e4c Linux-2.6.12-rc2 |
991 992 993 994 |
index &= ~((1UL << shift) - 1); index += 1UL << shift; if (index == 0) goto out; /* 32-bit wraparound */ |
7cf9c2c76 [PATCH] radix-tre... |
995 996 997 |
i++; if (i == RADIX_TREE_MAP_SIZE) goto out; |
1da177e4c Linux-2.6.12-rc2 |
998 |
} |
1da177e4c Linux-2.6.12-rc2 |
999 1000 1001 1002 1003 1004 |
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++; |
7cf9c2c76 [PATCH] radix-tre... |
1005 1006 |
if (!tag_get(slot, tag, j)) continue; |
7cf9c2c76 [PATCH] radix-tre... |
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 |
/* * 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). */ |
47feff2c8 radix-tree: add g... |
1017 1018 |
if (slot->slots[j]) { results[nr_found++] = &(slot->slots[j]); |
1da177e4c Linux-2.6.12-rc2 |
1019 1020 1021 1022 1023 1024 |
if (nr_found == max_items) goto out; } } } shift -= RADIX_TREE_MAP_SHIFT; |
2676a58c9 radix-tree: Disab... |
1025 |
slot = rcu_dereference_raw(slot->slots[i]); |
7cf9c2c76 [PATCH] radix-tre... |
1026 1027 1028 |
if (slot == NULL) break; } |
1da177e4c Linux-2.6.12-rc2 |
1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 |
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 |
daff89f32 [PATCH] radix-tre... |
1041 |
* @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4c Linux-2.6.12-rc2 |
1042 1043 1044 1045 1046 1047 1048 |
* * 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, |
daff89f32 [PATCH] radix-tre... |
1049 1050 |
unsigned long first_index, unsigned int max_items, unsigned int tag) |
1da177e4c Linux-2.6.12-rc2 |
1051 |
{ |
7cf9c2c76 [PATCH] radix-tre... |
1052 1053 |
struct radix_tree_node *node; unsigned long max_index; |
1da177e4c Linux-2.6.12-rc2 |
1054 |
unsigned long cur_index = first_index; |
7cf9c2c76 [PATCH] radix-tre... |
1055 |
unsigned int ret; |
1da177e4c Linux-2.6.12-rc2 |
1056 |
|
612d6c19d [PATCH] radix-tre... |
1057 1058 1059 |
/* check the root's tag bit */ if (!root_tag_get(root, tag)) return 0; |
2676a58c9 radix-tree: Disab... |
1060 |
node = rcu_dereference_raw(root->rnode); |
7cf9c2c76 [PATCH] radix-tre... |
1061 1062 |
if (!node) return 0; |
c0bc9875b radix-tree: use i... |
1063 |
if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c76 [PATCH] radix-tre... |
1064 1065 |
if (first_index > 0) return 0; |
c0bc9875b radix-tree: use i... |
1066 |
results[0] = node; |
7cf9c2c76 [PATCH] radix-tre... |
1067 1068 |
return 1; } |
27d20fddc radix-tree: fix R... |
1069 |
node = indirect_to_ptr(node); |
7cf9c2c76 [PATCH] radix-tre... |
1070 1071 1072 1073 |
max_index = radix_tree_maxindex(node->height); ret = 0; |
1da177e4c Linux-2.6.12-rc2 |
1074 |
while (ret < max_items) { |
47feff2c8 radix-tree: add g... |
1075 |
unsigned int nr_found, slots_found, i; |
1da177e4c Linux-2.6.12-rc2 |
1076 1077 1078 1079 |
unsigned long next_index; /* Index of next search */ if (cur_index > max_index) break; |
47feff2c8 radix-tree: add g... |
1080 1081 1082 1083 1084 1085 1086 1087 |
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; |
27d20fddc radix-tree: fix R... |
1088 1089 |
results[ret + nr_found] = indirect_to_ptr(rcu_dereference_raw(slot)); |
47feff2c8 radix-tree: add g... |
1090 1091 |
nr_found++; } |
1da177e4c Linux-2.6.12-rc2 |
1092 1093 1094 1095 1096 |
ret += nr_found; if (next_index == 0) break; cur_index = next_index; } |
7cf9c2c76 [PATCH] radix-tre... |
1097 |
|
1da177e4c Linux-2.6.12-rc2 |
1098 1099 1100 1101 1102 |
return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup_tag); /** |
47feff2c8 radix-tree: add g... |
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 |
* 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; |
2676a58c9 radix-tree: Disab... |
1128 |
node = rcu_dereference_raw(root->rnode); |
47feff2c8 radix-tree: add g... |
1129 1130 1131 1132 1133 1134 1135 1136 1137 |
if (!node) return 0; if (!radix_tree_is_indirect_ptr(node)) { if (first_index > 0) return 0; results[0] = (void **)&root->rnode; return 1; } |
27d20fddc radix-tree: fix R... |
1138 |
node = indirect_to_ptr(node); |
47feff2c8 radix-tree: add g... |
1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 |
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); /** |
a5f51c966 [PATCH] radix-tre... |
1163 1164 1165 1166 1167 1168 |
* 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 */ |
c0bc9875b radix-tree: use i... |
1169 |
while (root->height > 0) { |
a5f51c966 [PATCH] radix-tre... |
1170 |
struct radix_tree_node *to_free = root->rnode; |
7cf9c2c76 [PATCH] radix-tre... |
1171 |
void *newptr; |
a5f51c966 [PATCH] radix-tre... |
1172 |
|
c0bc9875b radix-tree: use i... |
1173 |
BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
27d20fddc radix-tree: fix R... |
1174 |
to_free = indirect_to_ptr(to_free); |
c0bc9875b radix-tree: use i... |
1175 1176 1177 1178 1179 1180 1181 1182 1183 |
/* * 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; |
7cf9c2c76 [PATCH] radix-tre... |
1184 1185 |
/* * We don't need rcu_assign_pointer(), since we are simply |
27d20fddc radix-tree: fix R... |
1186 1187 |
* moving the node from one part of the tree to another: if it * was safe to dereference the old pointer to it |
7cf9c2c76 [PATCH] radix-tre... |
1188 |
* (to_free->slots[0]), it will be safe to dereference the new |
27d20fddc radix-tree: fix R... |
1189 |
* one (root->rnode) as far as dependent read barriers go. |
7cf9c2c76 [PATCH] radix-tre... |
1190 1191 |
*/ newptr = to_free->slots[0]; |
c0bc9875b radix-tree: use i... |
1192 |
if (root->height > 1) |
27d20fddc radix-tree: fix R... |
1193 |
newptr = ptr_to_indirect(newptr); |
7cf9c2c76 [PATCH] radix-tre... |
1194 |
root->rnode = newptr; |
a5f51c966 [PATCH] radix-tre... |
1195 |
root->height--; |
27d20fddc radix-tree: fix R... |
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 |
/* * We have a dilemma here. The node's slot[0] must not be * NULLed in case there are concurrent lookups expecting to * find the item. However if this was a bottom-level node, * then it may be subject to the slot pointer being visible * to callers dereferencing it. If item corresponding to * slot[0] is subsequently deleted, these callers would expect * their slot to become empty sooner or later. * * For example, lockless pagecache will look up a slot, deref * the page pointer, and if the page is 0 refcount it means it * was concurrently deleted from pagecache so try the deref * again. Fortunately there is already a requirement for logic * to retry the entire slot lookup -- the indirect pointer * problem (replacing direct root node with an indirect pointer * also results in a stale slot). So tag the slot as indirect * to force callers to retry. */ if (root->height == 0) *((unsigned long *)&to_free->slots[0]) |= RADIX_TREE_INDIRECT_PTR; |
a5f51c966 [PATCH] radix-tre... |
1218 1219 1220 1221 1222 |
radix_tree_node_free(to_free); } } /** |
1da177e4c Linux-2.6.12-rc2 |
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 |
* 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) { |
26fb1589c fix the max path ... |
1233 1234 1235 1236 1237 |
/* * 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; |
612d6c19d [PATCH] radix-tre... |
1238 |
struct radix_tree_node *slot = NULL; |
7cf9c2c76 [PATCH] radix-tre... |
1239 |
struct radix_tree_node *to_free; |
1da177e4c Linux-2.6.12-rc2 |
1240 |
unsigned int height, shift; |
d5274261e [PATCH] radix tre... |
1241 1242 |
int tag; int offset; |
1da177e4c Linux-2.6.12-rc2 |
1243 1244 1245 1246 |
height = root->height; if (index > radix_tree_maxindex(height)) goto out; |
612d6c19d [PATCH] radix-tre... |
1247 |
slot = root->rnode; |
c0bc9875b radix-tree: use i... |
1248 |
if (height == 0) { |
612d6c19d [PATCH] radix-tre... |
1249 1250 1251 1252 |
root_tag_clear_all(root); root->rnode = NULL; goto out; } |
27d20fddc radix-tree: fix R... |
1253 |
slot = indirect_to_ptr(slot); |
612d6c19d [PATCH] radix-tre... |
1254 |
|
1da177e4c Linux-2.6.12-rc2 |
1255 1256 |
shift = (height - 1) * RADIX_TREE_MAP_SHIFT; pathp->node = NULL; |
1da177e4c Linux-2.6.12-rc2 |
1257 |
|
612d6c19d [PATCH] radix-tre... |
1258 |
do { |
201b6264f [PATCH] radix-tre... |
1259 |
if (slot == NULL) |
1da177e4c Linux-2.6.12-rc2 |
1260 |
goto out; |
d5274261e [PATCH] radix tre... |
1261 |
pathp++; |
1da177e4c Linux-2.6.12-rc2 |
1262 |
offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261e [PATCH] radix tre... |
1263 1264 |
pathp->offset = offset; pathp->node = slot; |
201b6264f [PATCH] radix-tre... |
1265 |
slot = slot->slots[offset]; |
1da177e4c Linux-2.6.12-rc2 |
1266 |
shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19d [PATCH] radix-tre... |
1267 1268 |
height--; } while (height > 0); |
1da177e4c Linux-2.6.12-rc2 |
1269 |
|
612d6c19d [PATCH] radix-tre... |
1270 |
if (slot == NULL) |
1da177e4c Linux-2.6.12-rc2 |
1271 |
goto out; |
1da177e4c Linux-2.6.12-rc2 |
1272 1273 1274 |
/* * Clear all tags associated with the just-deleted item */ |
daff89f32 [PATCH] radix-tre... |
1275 |
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19d [PATCH] radix-tre... |
1276 1277 |
if (tag_get(pathp->node, tag, pathp->offset)) radix_tree_tag_clear(root, index, tag); |
d5274261e [PATCH] radix tre... |
1278 |
} |
1da177e4c Linux-2.6.12-rc2 |
1279 |
|
7cf9c2c76 [PATCH] radix-tre... |
1280 |
to_free = NULL; |
201b6264f [PATCH] radix-tre... |
1281 |
/* Now free the nodes we do not need anymore */ |
612d6c19d [PATCH] radix-tre... |
1282 |
while (pathp->node) { |
201b6264f [PATCH] radix-tre... |
1283 |
pathp->node->slots[pathp->offset] = NULL; |
a5f51c966 [PATCH] radix-tre... |
1284 |
pathp->node->count--; |
7cf9c2c76 [PATCH] radix-tre... |
1285 1286 1287 1288 1289 1290 |
/* * 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); |
a5f51c966 [PATCH] radix-tre... |
1291 1292 |
if (pathp->node->count) { |
27d20fddc radix-tree: fix R... |
1293 |
if (pathp->node == indirect_to_ptr(root->rnode)) |
a5f51c966 [PATCH] radix-tre... |
1294 |
radix_tree_shrink(root); |
201b6264f [PATCH] radix-tre... |
1295 |
goto out; |
a5f51c966 [PATCH] radix-tre... |
1296 |
} |
201b6264f [PATCH] radix-tre... |
1297 1298 |
/* Node with zero slots in use so free it */ |
7cf9c2c76 [PATCH] radix-tre... |
1299 |
to_free = pathp->node; |
612d6c19d [PATCH] radix-tre... |
1300 |
pathp--; |
7cf9c2c76 [PATCH] radix-tre... |
1301 |
|
1da177e4c Linux-2.6.12-rc2 |
1302 |
} |
612d6c19d [PATCH] radix-tre... |
1303 |
root_tag_clear_all(root); |
201b6264f [PATCH] radix-tre... |
1304 |
root->height = 0; |
612d6c19d [PATCH] radix-tre... |
1305 |
root->rnode = NULL; |
7cf9c2c76 [PATCH] radix-tre... |
1306 1307 |
if (to_free) radix_tree_node_free(to_free); |
612d6c19d [PATCH] radix-tre... |
1308 |
|
1da177e4c Linux-2.6.12-rc2 |
1309 |
out: |
612d6c19d [PATCH] radix-tre... |
1310 |
return slot; |
1da177e4c Linux-2.6.12-rc2 |
1311 1312 1313 1314 1315 1316 1317 1318 |
} 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 */ |
daff89f32 [PATCH] radix-tre... |
1319 |
int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4c Linux-2.6.12-rc2 |
1320 |
{ |
612d6c19d [PATCH] radix-tre... |
1321 |
return root_tag_get(root, tag); |
1da177e4c Linux-2.6.12-rc2 |
1322 1323 1324 1325 |
} EXPORT_SYMBOL(radix_tree_tagged); static void |
51cc50685 SL*B: drop kmem c... |
1326 |
radix_tree_node_ctor(void *node) |
1da177e4c Linux-2.6.12-rc2 |
1327 1328 1329 1330 1331 1332 |
{ memset(node, 0, sizeof(struct radix_tree_node)); } static __init unsigned long __maxindex(unsigned int height) { |
430d275a3 avoid negative (a... |
1333 1334 1335 1336 1337 1338 1339 1340 |
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; |
1da177e4c Linux-2.6.12-rc2 |
1341 1342 1343 1344 1345 1346 1347 1348 1349 |
} 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); } |
1da177e4c Linux-2.6.12-rc2 |
1350 1351 1352 1353 1354 1355 1356 1357 |
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 */ |
8bb784428 Add suspend-relat... |
1358 |
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4c Linux-2.6.12-rc2 |
1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 |
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; } |
1da177e4c Linux-2.6.12-rc2 |
1369 1370 1371 1372 1373 |
void __init radix_tree_init(void) { radix_tree_node_cachep = kmem_cache_create("radix_tree_node", sizeof(struct radix_tree_node), 0, |
488514d17 Remove set_migrat... |
1374 1375 |
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, radix_tree_node_ctor); |
1da177e4c Linux-2.6.12-rc2 |
1376 1377 1378 |
radix_tree_init_maxindex(); hotcpu_notifier(radix_tree_callback, 0); } |