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lib/radix-tree.c
39.4 KB
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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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* Copyright (C) 2012 Konstantin Khlebnikov |
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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> |
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#include <linux/export.h> |
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#include <linux/radix-tree.h> #include <linux/percpu.h> #include <linux/slab.h> |
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#include <linux/kmemleak.h> |
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#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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#include <linux/preempt.h> /* in_interrupt() */ |
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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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/* |
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* The radix tree is variable-height, so an insert operation not only has * to build the branch to its corresponding item, it also has to build the * branch to existing items if the size has to be increased (by * radix_tree_extend). * * The worst case is a zero height tree with just a single item at index 0, * and then inserting an item at index ULONG_MAX. This requires 2 new branches * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. * Hence: */ #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) /* |
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* Per-cpu pool of preloaded nodes */ struct radix_tree_preload { int nr; |
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/* nodes->private_data points to next preallocated node */ struct radix_tree_node *nodes; |
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}; |
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static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
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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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/** * radix_tree_find_next_bit - find the next set bit in a memory region * * @addr: The address to base the search on * @size: The bitmap size in bits * @offset: The bitnumber to start searching at * * Unrollable variant of find_next_bit() for constant size arrays. * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. * Returns next bit offset, or size if nothing found. */ static __always_inline unsigned long radix_tree_find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset) { if (!__builtin_constant_p(size)) return find_next_bit(addr, size, offset); if (offset < size) { unsigned long tmp; addr += offset / BITS_PER_LONG; tmp = *addr >> (offset % BITS_PER_LONG); if (tmp) return __ffs(tmp) + offset; offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); while (offset < size) { tmp = *++addr; if (tmp) return __ffs(tmp) + offset; offset += BITS_PER_LONG; } } return size; } |
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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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/* * Preload code isn't irq safe and it doesn't make sence to use * preloading in the interrupt anyway as all the allocations have to * be atomic. So just do normal allocation when in interrupt. */ if (!(gfp_mask & __GFP_WAIT) && !in_interrupt()) { |
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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 = this_cpu_ptr(&radix_tree_preloads); |
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if (rtp->nr) { |
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ret = rtp->nodes; rtp->nodes = ret->private_data; ret->private_data = NULL; |
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rtp->nr--; } |
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/* * Update the allocation stack trace as this is more useful * for debugging. */ kmemleak_update_trace(ret); |
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} |
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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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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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static 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(); |
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rtp = this_cpu_ptr(&radix_tree_preloads); |
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while (rtp->nr < RADIX_TREE_PRELOAD_SIZE) { |
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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(); |
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rtp = this_cpu_ptr(&radix_tree_preloads); |
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if (rtp->nr < RADIX_TREE_PRELOAD_SIZE) { node->private_data = rtp->nodes; rtp->nodes = node; rtp->nr++; } else { |
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kmem_cache_free(radix_tree_node_cachep, node); |
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} |
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} ret = 0; out: return ret; } |
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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. * * To make use of this facility, the radix tree must be initialised without * __GFP_WAIT being passed to INIT_RADIX_TREE(). */ int radix_tree_preload(gfp_t gfp_mask) { /* Warn on non-sensical use... */ WARN_ON_ONCE(!(gfp_mask & __GFP_WAIT)); return __radix_tree_preload(gfp_mask); } |
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EXPORT_SYMBOL(radix_tree_preload); |
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/* |
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* The same as above function, except we don't guarantee preloading happens. * We do it, if we decide it helps. On success, return zero with preemption * disabled. On error, return -ENOMEM with preemption not disabled. */ int radix_tree_maybe_preload(gfp_t gfp_mask) { if (gfp_mask & __GFP_WAIT) return __radix_tree_preload(gfp_mask); /* Preloading doesn't help anything with this gfp mask, skip it */ preempt_disable(); return 0; } EXPORT_SYMBOL(radix_tree_maybe_preload); /* |
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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; |
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struct radix_tree_node *slot; |
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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; |
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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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/* Increase the height. */ |
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newheight = root->height+1; |
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BUG_ON(newheight & ~RADIX_TREE_HEIGHT_MASK); node->path = newheight; |
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node->count = 1; |
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node->parent = NULL; slot = root->rnode; if (newheight > 1) { slot = indirect_to_ptr(slot); slot->parent = node; } node->slots[0] = slot; |
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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; } /** |
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* __radix_tree_create - create a slot in a radix tree |
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* @root: radix tree root * @index: index key |
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* @nodep: returns node * @slotp: returns slot |
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* |
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* Create, if necessary, and return the node and slot for an item * at position @index in the radix tree @root. * * Until there is more than one item in the tree, no nodes are * allocated and @root->rnode is used as a direct slot instead of * pointing to a node, in which case *@nodep will be NULL. * * Returns -ENOMEM, or 0 for success. |
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*/ |
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int __radix_tree_create(struct radix_tree_root *root, unsigned long index, struct radix_tree_node **nodep, void ***slotp) |
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{ |
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struct radix_tree_node *node = NULL, *slot; |
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unsigned int height, shift, offset; |
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int error; /* 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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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->path = height; |
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slot->parent = node; |
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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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slot->path |= offset << RADIX_TREE_HEIGHT_SHIFT; |
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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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if (nodep) *nodep = node; if (slotp) *slotp = node ? node->slots + offset : (void **)&root->rnode; 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; void **slot; int error; BUG_ON(radix_tree_is_indirect_ptr(item)); error = __radix_tree_create(root, index, &node, &slot); if (error) return error; if (*slot != NULL) |
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return -EEXIST; |
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rcu_assign_pointer(*slot, item); |
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if (node) { node->count++; |
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BUG_ON(tag_get(node, 0, index & RADIX_TREE_MAP_MASK)); BUG_ON(tag_get(node, 1, index & RADIX_TREE_MAP_MASK)); |
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} else { |
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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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/** * __radix_tree_lookup - lookup an item in a radix tree * @root: radix tree root * @index: index key * @nodep: returns node * @slotp: returns slot * * Lookup and return the item at position @index in the radix * tree @root. * * Until there is more than one item in the tree, no nodes are * allocated and @root->rnode is used as a direct slot instead of * pointing to a node, in which case *@nodep will be NULL. |
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*/ |
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void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, struct radix_tree_node **nodep, void ***slotp) |
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{ |
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struct radix_tree_node *node, *parent; |
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unsigned int height, shift; |
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void **slot; |
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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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if (nodep) *nodep = NULL; if (slotp) *slotp = (void **)&root->rnode; return node; |
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} |
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node = indirect_to_ptr(node); |
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height = node->path & RADIX_TREE_HEIGHT_MASK; |
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if (index > radix_tree_maxindex(height)) return NULL; |
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shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
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do { |
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parent = node; slot = 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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if (nodep) *nodep = parent; if (slotp) *slotp = slot; return 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) { |
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void **slot; if (!__radix_tree_lookup(root, index, NULL, &slot)) return NULL; return slot; |
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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(root, index, NULL, NULL); |
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|
560 561 562 563 564 565 566 567 568 |
} 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 * |
daff89f32
|
569 570 |
* Set the search tag (which must be < RADIX_TREE_MAX_TAGS) * corresponding to @index in the radix tree. From |
1da177e4c
|
571 572 573 574 575 576 |
* 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, |
daff89f32
|
577 |
unsigned long index, unsigned int tag) |
1da177e4c
|
578 579 |
{ unsigned int height, shift; |
201b6264f
|
580 |
struct radix_tree_node *slot; |
1da177e4c
|
581 582 |
height = root->height; |
4c91c3648
|
583 |
BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4c
|
584 |
|
27d20fddc
|
585 |
slot = indirect_to_ptr(root->rnode); |
612d6c19d
|
586 |
shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4c
|
587 588 589 590 591 |
while (height > 0) { int offset; offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261e
|
592 593 |
if (!tag_get(slot, tag, offset)) tag_set(slot, tag, offset); |
201b6264f
|
594 595 |
slot = slot->slots[offset]; BUG_ON(slot == NULL); |
1da177e4c
|
596 597 598 |
shift -= RADIX_TREE_MAP_SHIFT; height--; } |
612d6c19d
|
599 600 601 |
/* set the root's tag bit */ if (slot && !root_tag_get(root, tag)) root_tag_set(root, tag); |
201b6264f
|
602 |
return slot; |
1da177e4c
|
603 604 605 606 607 608 609 610 611 |
} 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
|
612 613 |
* Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) * corresponding to @index in the radix tree. If |
1da177e4c
|
614 615 616 617 618 619 620 |
* 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
|
621 |
unsigned long index, unsigned int tag) |
1da177e4c
|
622 |
{ |
e2bdb933a
|
623 |
struct radix_tree_node *node = NULL; |
612d6c19d
|
624 |
struct radix_tree_node *slot = NULL; |
1da177e4c
|
625 |
unsigned int height, shift; |
e2bdb933a
|
626 |
int uninitialized_var(offset); |
1da177e4c
|
627 628 629 630 |
height = root->height; if (index > radix_tree_maxindex(height)) goto out; |
e2bdb933a
|
631 |
shift = height * RADIX_TREE_MAP_SHIFT; |
27d20fddc
|
632 |
slot = indirect_to_ptr(root->rnode); |
1da177e4c
|
633 |
|
e2bdb933a
|
634 |
while (shift) { |
201b6264f
|
635 |
if (slot == NULL) |
1da177e4c
|
636 |
goto out; |
e2bdb933a
|
637 |
shift -= RADIX_TREE_MAP_SHIFT; |
1da177e4c
|
638 |
offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
e2bdb933a
|
639 |
node = slot; |
201b6264f
|
640 |
slot = slot->slots[offset]; |
1da177e4c
|
641 |
} |
612d6c19d
|
642 |
if (slot == NULL) |
1da177e4c
|
643 |
goto out; |
e2bdb933a
|
644 645 |
while (node) { if (!tag_get(node, tag, offset)) |
d5274261e
|
646 |
goto out; |
e2bdb933a
|
647 648 |
tag_clear(node, tag, offset); if (any_tag_set(node, tag)) |
6e954b9e9
|
649 |
goto out; |
e2bdb933a
|
650 651 652 653 |
index >>= RADIX_TREE_MAP_SHIFT; offset = index & RADIX_TREE_MAP_MASK; node = node->parent; |
612d6c19d
|
654 655 656 657 658 |
} /* clear the root's tag bit */ if (root_tag_get(root, tag)) root_tag_clear(root, tag); |
1da177e4c
|
659 |
out: |
612d6c19d
|
660 |
return slot; |
1da177e4c
|
661 662 |
} EXPORT_SYMBOL(radix_tree_tag_clear); |
1da177e4c
|
663 |
/** |
32605a181
|
664 665 666 |
* radix_tree_tag_get - get a tag on a radix tree node * @root: radix tree root * @index: index key |
daff89f32
|
667 |
* @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4c
|
668 |
* |
32605a181
|
669 |
* Return values: |
1da177e4c
|
670 |
* |
612d6c19d
|
671 672 |
* 0: tag not present or not set * 1: tag set |
ce82653d6
|
673 674 675 676 |
* * 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
|
677 678 |
*/ int radix_tree_tag_get(struct radix_tree_root *root, |
daff89f32
|
679 |
unsigned long index, unsigned int tag) |
1da177e4c
|
680 681 |
{ unsigned int height, shift; |
7cf9c2c76
|
682 |
struct radix_tree_node *node; |
1da177e4c
|
683 |
|
612d6c19d
|
684 685 686 |
/* check the root's tag bit */ if (!root_tag_get(root, tag)) return 0; |
2676a58c9
|
687 |
node = rcu_dereference_raw(root->rnode); |
7cf9c2c76
|
688 689 |
if (node == NULL) return 0; |
c0bc9875b
|
690 |
if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c76
|
691 |
return (index == 0); |
27d20fddc
|
692 |
node = indirect_to_ptr(node); |
7cf9c2c76
|
693 |
|
449dd6984
|
694 |
height = node->path & RADIX_TREE_HEIGHT_MASK; |
7cf9c2c76
|
695 696 |
if (index > radix_tree_maxindex(height)) return 0; |
612d6c19d
|
697 |
|
1da177e4c
|
698 |
shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4c
|
699 700 701 |
for ( ; ; ) { int offset; |
7cf9c2c76
|
702 |
if (node == NULL) |
1da177e4c
|
703 704 705 |
return 0; offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
7cf9c2c76
|
706 |
if (!tag_get(node, tag, offset)) |
3fa36acbc
|
707 |
return 0; |
ce82653d6
|
708 |
if (height == 1) |
3fa36acbc
|
709 |
return 1; |
2676a58c9
|
710 |
node = rcu_dereference_raw(node->slots[offset]); |
1da177e4c
|
711 712 713 714 715 |
shift -= RADIX_TREE_MAP_SHIFT; height--; } } EXPORT_SYMBOL(radix_tree_tag_get); |
1da177e4c
|
716 |
|
6df8ba4f8
|
717 |
/** |
78c1d7848
|
718 719 720 721 722 723 724 725 726 727 728 729 |
* radix_tree_next_chunk - find next chunk of slots for iteration * * @root: radix tree root * @iter: iterator state * @flags: RADIX_TREE_ITER_* flags and tag index * Returns: pointer to chunk first slot, or NULL if iteration is over */ void **radix_tree_next_chunk(struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned flags) { unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK; struct radix_tree_node *rnode, *node; |
449dd6984
|
730 |
unsigned long index, offset, height; |
78c1d7848
|
731 732 733 734 735 736 737 738 739 |
if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) return NULL; /* * Catch next_index overflow after ~0UL. iter->index never overflows * during iterating; it can be zero only at the beginning. * And we cannot overflow iter->next_index in a single step, * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. |
fffaee365
|
740 741 742 |
* * This condition also used by radix_tree_next_slot() to stop * contiguous iterating, and forbid swithing to the next chunk. |
78c1d7848
|
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 |
*/ index = iter->next_index; if (!index && iter->index) return NULL; rnode = rcu_dereference_raw(root->rnode); if (radix_tree_is_indirect_ptr(rnode)) { rnode = indirect_to_ptr(rnode); } else if (rnode && !index) { /* Single-slot tree */ iter->index = 0; iter->next_index = 1; iter->tags = 1; return (void **)&root->rnode; } else return NULL; restart: |
449dd6984
|
761 762 |
height = rnode->path & RADIX_TREE_HEIGHT_MASK; shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
78c1d7848
|
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 |
offset = index >> shift; /* Index outside of the tree */ if (offset >= RADIX_TREE_MAP_SIZE) return NULL; node = rnode; while (1) { if ((flags & RADIX_TREE_ITER_TAGGED) ? !test_bit(offset, node->tags[tag]) : !node->slots[offset]) { /* Hole detected */ if (flags & RADIX_TREE_ITER_CONTIG) return NULL; if (flags & RADIX_TREE_ITER_TAGGED) offset = radix_tree_find_next_bit( node->tags[tag], RADIX_TREE_MAP_SIZE, offset + 1); else while (++offset < RADIX_TREE_MAP_SIZE) { if (node->slots[offset]) break; } index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1); index += offset << shift; /* Overflow after ~0UL */ if (!index) return NULL; if (offset == RADIX_TREE_MAP_SIZE) goto restart; } /* This is leaf-node */ if (!shift) break; node = rcu_dereference_raw(node->slots[offset]); if (node == NULL) goto restart; shift -= RADIX_TREE_MAP_SHIFT; offset = (index >> shift) & RADIX_TREE_MAP_MASK; } /* Update the iterator state */ iter->index = index; iter->next_index = (index | RADIX_TREE_MAP_MASK) + 1; /* Construct iter->tags bit-mask from node->tags[tag] array */ if (flags & RADIX_TREE_ITER_TAGGED) { unsigned tag_long, tag_bit; tag_long = offset / BITS_PER_LONG; tag_bit = offset % BITS_PER_LONG; iter->tags = node->tags[tag][tag_long] >> tag_bit; /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ if (tag_long < RADIX_TREE_TAG_LONGS - 1) { /* Pick tags from next element */ if (tag_bit) iter->tags |= node->tags[tag][tag_long + 1] << (BITS_PER_LONG - tag_bit); /* Clip chunk size, here only BITS_PER_LONG tags */ iter->next_index = index + BITS_PER_LONG; } } return node->slots + offset; } EXPORT_SYMBOL(radix_tree_next_chunk); /** |
ebf8aa44b
|
835 836 837 838 839 840 841 842 843 844 845 846 847 848 |
* 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
|
849 850 851 852 853 854 855 |
* 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
|
856 857 |
* The function returns number of leaves where the tag was set and sets * *first_indexp to the first unscanned index. |
d5ed3a4af
|
858 859 |
* WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must * be prepared to handle that. |
ebf8aa44b
|
860 861 862 863 864 865 |
*/ 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
|
866 |
unsigned int height = root->height; |
e2bdb933a
|
867 |
struct radix_tree_node *node = NULL; |
144dcfc01
|
868 869 870 871 |
struct radix_tree_node *slot; unsigned int shift; unsigned long tagged = 0; unsigned long index = *first_indexp; |
ebf8aa44b
|
872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 |
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
|
889 |
slot = indirect_to_ptr(root->rnode); |
ebf8aa44b
|
890 891 |
for (;;) { |
e2bdb933a
|
892 |
unsigned long upindex; |
ebf8aa44b
|
893 894 895 896 897 898 899 |
int offset; offset = (index >> shift) & RADIX_TREE_MAP_MASK; if (!slot->slots[offset]) goto next; if (!tag_get(slot, iftag, offset)) goto next; |
e2bdb933a
|
900 |
if (shift) { |
144dcfc01
|
901 |
/* Go down one level */ |
144dcfc01
|
902 |
shift -= RADIX_TREE_MAP_SHIFT; |
e2bdb933a
|
903 |
node = slot; |
144dcfc01
|
904 905 906 907 908 909 |
slot = slot->slots[offset]; continue; } /* tag the leaf */ tagged++; |
ebf8aa44b
|
910 |
tag_set(slot, settag, offset); |
144dcfc01
|
911 912 |
/* walk back up the path tagging interior nodes */ |
e2bdb933a
|
913 914 915 916 |
upindex = index; while (node) { upindex >>= RADIX_TREE_MAP_SHIFT; offset = upindex & RADIX_TREE_MAP_MASK; |
144dcfc01
|
917 |
/* stop if we find a node with the tag already set */ |
e2bdb933a
|
918 |
if (tag_get(node, settag, offset)) |
144dcfc01
|
919 |
break; |
e2bdb933a
|
920 921 |
tag_set(node, settag, offset); node = node->parent; |
ebf8aa44b
|
922 |
} |
144dcfc01
|
923 |
|
e2bdb933a
|
924 925 926 927 928 929 930 931 |
/* * Small optimization: now clear that node pointer. * Since all of this slot's ancestors now have the tag set * from setting it above, we have no further need to walk * back up the tree setting tags, until we update slot to * point to another radix_tree_node. */ node = NULL; |
ebf8aa44b
|
932 933 934 |
next: /* Go to next item at level determined by 'shift' */ index = ((index >> shift) + 1) << shift; |
d5ed3a4af
|
935 936 |
/* Overflow can happen when last_index is ~0UL... */ if (index > last_index || !index) |
ebf8aa44b
|
937 938 939 940 941 942 943 944 945 |
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. */ |
e2bdb933a
|
946 |
slot = slot->parent; |
ebf8aa44b
|
947 948 949 950 |
shift += RADIX_TREE_MAP_SHIFT; } } /* |
ac15ee691
|
951 952 |
* 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
|
953 |
*/ |
ac15ee691
|
954 955 |
if (tagged > 0) root_tag_set(root, settag); |
ebf8aa44b
|
956 957 958 959 960 |
*first_indexp = index; return tagged; } EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); |
1da177e4c
|
961 962 963 964 965 966 967 968 969 970 971 972 |
/** * 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
|
973 974 975 976 977 978 |
* * 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
|
979 980 981 982 983 |
*/ unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items) { |
cebbd29e1
|
984 985 986 |
struct radix_tree_iter iter; void **slot; unsigned int ret = 0; |
7cf9c2c76
|
987 |
|
cebbd29e1
|
988 |
if (unlikely(!max_items)) |
7cf9c2c76
|
989 |
return 0; |
1da177e4c
|
990 |
|
cebbd29e1
|
991 992 993 994 995 |
radix_tree_for_each_slot(slot, root, &iter, first_index) { results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); if (!results[ret]) continue; if (++ret == max_items) |
1da177e4c
|
996 |
break; |
1da177e4c
|
997 |
} |
7cf9c2c76
|
998 |
|
1da177e4c
|
999 1000 1001 |
return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup); |
47feff2c8
|
1002 1003 1004 1005 |
/** * 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 |
6328650bb
|
1006 |
* @indices: where their indices should be placed (but usually NULL) |
47feff2c8
|
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 |
* @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 |
6328650bb
|
1021 1022 |
radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results, unsigned long *indices, |
47feff2c8
|
1023 1024 |
unsigned long first_index, unsigned int max_items) { |
cebbd29e1
|
1025 1026 1027 |
struct radix_tree_iter iter; void **slot; unsigned int ret = 0; |
47feff2c8
|
1028 |
|
cebbd29e1
|
1029 |
if (unlikely(!max_items)) |
47feff2c8
|
1030 |
return 0; |
cebbd29e1
|
1031 1032 |
radix_tree_for_each_slot(slot, root, &iter, first_index) { results[ret] = slot; |
6328650bb
|
1033 |
if (indices) |
cebbd29e1
|
1034 1035 |
indices[ret] = iter.index; if (++ret == max_items) |
47feff2c8
|
1036 |
break; |
47feff2c8
|
1037 1038 1039 1040 1041 |
} return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup_slot); |
1da177e4c
|
1042 1043 1044 1045 1046 1047 1048 |
/** * 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
|
1049 |
* @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4c
|
1050 1051 1052 1053 1054 1055 1056 |
* * 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
|
1057 1058 |
unsigned long first_index, unsigned int max_items, unsigned int tag) |
1da177e4c
|
1059 |
{ |
cebbd29e1
|
1060 1061 1062 |
struct radix_tree_iter iter; void **slot; unsigned int ret = 0; |
612d6c19d
|
1063 |
|
cebbd29e1
|
1064 |
if (unlikely(!max_items)) |
7cf9c2c76
|
1065 |
return 0; |
cebbd29e1
|
1066 1067 1068 1069 1070 |
radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); if (!results[ret]) continue; if (++ret == max_items) |
1da177e4c
|
1071 |
break; |
1da177e4c
|
1072 |
} |
7cf9c2c76
|
1073 |
|
1da177e4c
|
1074 1075 1076 1077 1078 |
return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup_tag); /** |
47feff2c8
|
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 |
* 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) { |
cebbd29e1
|
1096 1097 1098 |
struct radix_tree_iter iter; void **slot; unsigned int ret = 0; |
47feff2c8
|
1099 |
|
cebbd29e1
|
1100 |
if (unlikely(!max_items)) |
47feff2c8
|
1101 |
return 0; |
cebbd29e1
|
1102 1103 1104 |
radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { results[ret] = slot; if (++ret == max_items) |
47feff2c8
|
1105 |
break; |
47feff2c8
|
1106 1107 1108 1109 1110 |
} return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); |
e504f3fdd
|
1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 |
#if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP) #include <linux/sched.h> /* for cond_resched() */ /* * This linear search is at present only useful to shmem_unuse_inode(). */ static unsigned long __locate(struct radix_tree_node *slot, void *item, unsigned long index, unsigned long *found_index) { unsigned int shift, height; unsigned long i; |
449dd6984
|
1122 |
height = slot->path & RADIX_TREE_HEIGHT_MASK; |
e504f3fdd
|
1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 |
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_raw(slot->slots[i]); if (slot == NULL) goto out; } /* Bottom level: check items */ for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { if (slot->slots[i] == item) { *found_index = index + i; index = 0; goto out; } } index += RADIX_TREE_MAP_SIZE; out: return index; } /** * radix_tree_locate_item - search through radix tree for item * @root: radix tree root * @item: item to be found * * Returns index where item was found, or -1 if not found. * Caller must hold no lock (since this time-consuming function needs * to be preemptible), and must check afterwards if item is still there. */ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) { struct radix_tree_node *node; unsigned long max_index; unsigned long cur_index = 0; unsigned long found_index = -1; do { rcu_read_lock(); node = rcu_dereference_raw(root->rnode); if (!radix_tree_is_indirect_ptr(node)) { rcu_read_unlock(); if (node == item) found_index = 0; break; } node = indirect_to_ptr(node); |
449dd6984
|
1185 1186 |
max_index = radix_tree_maxindex(node->path & RADIX_TREE_HEIGHT_MASK); |
5f30fc94c
|
1187 1188 |
if (cur_index > max_index) { rcu_read_unlock(); |
e504f3fdd
|
1189 |
break; |
5f30fc94c
|
1190 |
} |
e504f3fdd
|
1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 |
cur_index = __locate(node, item, cur_index, &found_index); rcu_read_unlock(); cond_resched(); } while (cur_index != 0 && cur_index <= max_index); return found_index; } #else unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) { return -1; } #endif /* CONFIG_SHMEM && CONFIG_SWAP */ |
47feff2c8
|
1205 1206 |
/** |
a5f51c966
|
1207 1208 1209 1210 1211 1212 |
* 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
|
1213 |
while (root->height > 0) { |
a5f51c966
|
1214 |
struct radix_tree_node *to_free = root->rnode; |
e2bdb933a
|
1215 |
struct radix_tree_node *slot; |
a5f51c966
|
1216 |
|
c0bc9875b
|
1217 |
BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
27d20fddc
|
1218 |
to_free = indirect_to_ptr(to_free); |
c0bc9875b
|
1219 1220 1221 1222 1223 1224 1225 1226 1227 |
/* * 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
|
1228 1229 |
/* * We don't need rcu_assign_pointer(), since we are simply |
27d20fddc
|
1230 1231 |
* moving the node from one part of the tree to another: if it * was safe to dereference the old pointer to it |
7cf9c2c76
|
1232 |
* (to_free->slots[0]), it will be safe to dereference the new |
27d20fddc
|
1233 |
* one (root->rnode) as far as dependent read barriers go. |
7cf9c2c76
|
1234 |
*/ |
e2bdb933a
|
1235 1236 1237 1238 1239 1240 |
slot = to_free->slots[0]; if (root->height > 1) { slot->parent = NULL; slot = ptr_to_indirect(slot); } root->rnode = slot; |
a5f51c966
|
1241 |
root->height--; |
27d20fddc
|
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 |
/* * 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
|
1264 1265 1266 1267 1268 |
radix_tree_node_free(to_free); } } /** |
139e56166
|
1269 1270 |
* __radix_tree_delete_node - try to free node after clearing a slot * @root: radix tree root |
139e56166
|
1271 1272 1273 1274 1275 1276 1277 1278 |
* @node: node containing @index * * After clearing the slot at @index in @node from radix tree * rooted at @root, call this function to attempt freeing the * node and shrinking the tree. * * Returns %true if @node was freed, %false otherwise. */ |
449dd6984
|
1279 |
bool __radix_tree_delete_node(struct radix_tree_root *root, |
139e56166
|
1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 |
struct radix_tree_node *node) { bool deleted = false; do { struct radix_tree_node *parent; if (node->count) { if (node == indirect_to_ptr(root->rnode)) { radix_tree_shrink(root); if (root->height == 0) deleted = true; } return deleted; } parent = node->parent; if (parent) { |
449dd6984
|
1298 |
unsigned int offset; |
139e56166
|
1299 |
|
449dd6984
|
1300 1301 |
offset = node->path >> RADIX_TREE_HEIGHT_SHIFT; parent->slots[offset] = NULL; |
139e56166
|
1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 |
parent->count--; } else { root_tag_clear_all(root); root->height = 0; root->rnode = NULL; } radix_tree_node_free(node); deleted = true; node = parent; } while (node); return deleted; } /** |
53c59f262
|
1319 |
* radix_tree_delete_item - delete an item from a radix tree |
1da177e4c
|
1320 1321 |
* @root: radix tree root * @index: index key |
53c59f262
|
1322 |
* @item: expected item |
1da177e4c
|
1323 |
* |
53c59f262
|
1324 |
* Remove @item at @index from the radix tree rooted at @root. |
1da177e4c
|
1325 |
* |
53c59f262
|
1326 1327 |
* Returns the address of the deleted item, or NULL if it was not present * or the entry at the given @index was not @item. |
1da177e4c
|
1328 |
*/ |
53c59f262
|
1329 1330 |
void *radix_tree_delete_item(struct radix_tree_root *root, unsigned long index, void *item) |
1da177e4c
|
1331 |
{ |
139e56166
|
1332 1333 1334 1335 |
struct radix_tree_node *node; unsigned int offset; void **slot; void *entry; |
d5274261e
|
1336 |
int tag; |
1da177e4c
|
1337 |
|
139e56166
|
1338 1339 1340 |
entry = __radix_tree_lookup(root, index, &node, &slot); if (!entry) return NULL; |
1da177e4c
|
1341 |
|
139e56166
|
1342 1343 1344 1345 |
if (item && entry != item) return NULL; if (!node) { |
612d6c19d
|
1346 1347 |
root_tag_clear_all(root); root->rnode = NULL; |
139e56166
|
1348 |
return entry; |
612d6c19d
|
1349 |
} |
1da177e4c
|
1350 |
|
139e56166
|
1351 |
offset = index & RADIX_TREE_MAP_MASK; |
53c59f262
|
1352 |
|
1da177e4c
|
1353 |
/* |
e2bdb933a
|
1354 1355 |
* Clear all tags associated with the item to be deleted. * This way of doing it would be inefficient, but seldom is any set. |
1da177e4c
|
1356 |
*/ |
daff89f32
|
1357 |
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
e2bdb933a
|
1358 |
if (tag_get(node, tag, offset)) |
612d6c19d
|
1359 |
radix_tree_tag_clear(root, index, tag); |
d5274261e
|
1360 |
} |
1da177e4c
|
1361 |
|
139e56166
|
1362 1363 |
node->slots[offset] = NULL; node->count--; |
e2bdb933a
|
1364 |
|
449dd6984
|
1365 |
__radix_tree_delete_node(root, node); |
612d6c19d
|
1366 |
|
139e56166
|
1367 |
return entry; |
1da177e4c
|
1368 |
} |
53c59f262
|
1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 |
EXPORT_SYMBOL(radix_tree_delete_item); /** * 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) { return radix_tree_delete_item(root, index, NULL); } |
1da177e4c
|
1384 1385 1386 1387 1388 1389 1390 |
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
|
1391 |
int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4c
|
1392 |
{ |
612d6c19d
|
1393 |
return root_tag_get(root, tag); |
1da177e4c
|
1394 1395 1396 1397 |
} EXPORT_SYMBOL(radix_tree_tagged); static void |
449dd6984
|
1398 |
radix_tree_node_ctor(void *arg) |
1da177e4c
|
1399 |
{ |
449dd6984
|
1400 1401 1402 1403 |
struct radix_tree_node *node = arg; memset(node, 0, sizeof(*node)); INIT_LIST_HEAD(&node->private_list); |
1da177e4c
|
1404 1405 1406 1407 |
} static __init unsigned long __maxindex(unsigned int height) { |
430d275a3
|
1408 1409 1410 1411 1412 1413 1414 1415 |
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
|
1416 1417 1418 1419 1420 1421 1422 1423 1424 |
} 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
|
1425 1426 1427 1428 1429 1430 |
static int radix_tree_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { int cpu = (long)hcpu; struct radix_tree_preload *rtp; |
9d2a8da00
|
1431 |
struct radix_tree_node *node; |
1da177e4c
|
1432 1433 |
/* Free per-cpu pool of perloaded nodes */ |
8bb784428
|
1434 |
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4c
|
1435 1436 |
rtp = &per_cpu(radix_tree_preloads, cpu); while (rtp->nr) { |
9d2a8da00
|
1437 1438 1439 1440 |
node = rtp->nodes; rtp->nodes = node->private_data; kmem_cache_free(radix_tree_node_cachep, node); rtp->nr--; |
1da177e4c
|
1441 1442 1443 1444 |
} } return NOTIFY_OK; } |
1da177e4c
|
1445 1446 1447 1448 1449 |
void __init radix_tree_init(void) { radix_tree_node_cachep = kmem_cache_create("radix_tree_node", sizeof(struct radix_tree_node), 0, |
488514d17
|
1450 1451 |
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, radix_tree_node_ctor); |
1da177e4c
|
1452 1453 1454 |
radix_tree_init_maxindex(); hotcpu_notifier(radix_tree_callback, 0); } |