Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2001 Momchil Velikov |
| 3 | * Portions Copyright (C) 2001 Christoph Hellwig |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 4 | * Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com> |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 5 | * Copyright (C) 2006 Nick Piggin |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2, or (at |
| 10 | * your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, but |
| 13 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 20 | */ |
| 21 | |
| 22 | #include <linux/errno.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/kernel.h> |
| 25 | #include <linux/module.h> |
| 26 | #include <linux/radix-tree.h> |
| 27 | #include <linux/percpu.h> |
| 28 | #include <linux/slab.h> |
| 29 | #include <linux/notifier.h> |
| 30 | #include <linux/cpu.h> |
| 31 | #include <linux/gfp.h> |
| 32 | #include <linux/string.h> |
| 33 | #include <linux/bitops.h> |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 34 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
| 36 | |
| 37 | #ifdef __KERNEL__ |
Nick Piggin | cfd9b7d | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 38 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | #else |
| 40 | #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ |
| 41 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
| 43 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) |
| 44 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) |
| 45 | |
| 46 | #define RADIX_TREE_TAG_LONGS \ |
| 47 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) |
| 48 | |
| 49 | struct radix_tree_node { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 50 | unsigned int height; /* Height from the bottom */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | unsigned int count; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 52 | struct rcu_head rcu_head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | void *slots[RADIX_TREE_MAP_SIZE]; |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 54 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | }; |
| 56 | |
| 57 | struct radix_tree_path { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 58 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | int offset; |
| 60 | }; |
| 61 | |
| 62 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame^] | 63 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ |
| 64 | RADIX_TREE_MAP_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame^] | 66 | /* |
| 67 | * The height_to_maxindex array needs to be one deeper than the maximum |
| 68 | * path as height 0 holds only 1 entry. |
| 69 | */ |
| 70 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
| 72 | /* |
| 73 | * Radix tree node cache. |
| 74 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 75 | static struct kmem_cache *radix_tree_node_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | |
| 77 | /* |
| 78 | * Per-cpu pool of preloaded nodes |
| 79 | */ |
| 80 | struct radix_tree_preload { |
| 81 | int nr; |
| 82 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; |
| 83 | }; |
| 84 | DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
| 85 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 86 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
| 87 | { |
| 88 | return root->gfp_mask & __GFP_BITS_MASK; |
| 89 | } |
| 90 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | /* |
| 92 | * This assumes that the caller has performed appropriate preallocation, and |
| 93 | * that the caller has pinned this thread of control to the current CPU. |
| 94 | */ |
| 95 | static struct radix_tree_node * |
| 96 | radix_tree_node_alloc(struct radix_tree_root *root) |
| 97 | { |
| 98 | struct radix_tree_node *ret; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 99 | gfp_t gfp_mask = root_gfp_mask(root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 101 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
| 102 | if (ret == NULL && !(gfp_mask & __GFP_WAIT)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | struct radix_tree_preload *rtp; |
| 104 | |
| 105 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 106 | if (rtp->nr) { |
| 107 | ret = rtp->nodes[rtp->nr - 1]; |
| 108 | rtp->nodes[rtp->nr - 1] = NULL; |
| 109 | rtp->nr--; |
| 110 | } |
| 111 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 112 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | return ret; |
| 114 | } |
| 115 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 116 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
| 117 | { |
| 118 | struct radix_tree_node *node = |
| 119 | container_of(head, struct radix_tree_node, rcu_head); |
| 120 | kmem_cache_free(radix_tree_node_cachep, node); |
| 121 | } |
| 122 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | static inline void |
| 124 | radix_tree_node_free(struct radix_tree_node *node) |
| 125 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 126 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | } |
| 128 | |
| 129 | /* |
| 130 | * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| 131 | * ensure that the addition of a single element in the tree cannot fail. On |
| 132 | * success, return zero, with preemption disabled. On error, return -ENOMEM |
| 133 | * with preemption not disabled. |
| 134 | */ |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 135 | int radix_tree_preload(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | { |
| 137 | struct radix_tree_preload *rtp; |
| 138 | struct radix_tree_node *node; |
| 139 | int ret = -ENOMEM; |
| 140 | |
| 141 | preempt_disable(); |
| 142 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 143 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { |
| 144 | preempt_enable(); |
| 145 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
| 146 | if (node == NULL) |
| 147 | goto out; |
| 148 | preempt_disable(); |
| 149 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 150 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) |
| 151 | rtp->nodes[rtp->nr++] = node; |
| 152 | else |
| 153 | kmem_cache_free(radix_tree_node_cachep, node); |
| 154 | } |
| 155 | ret = 0; |
| 156 | out: |
| 157 | return ret; |
| 158 | } |
David Chinner | d7f0923 | 2007-07-14 16:05:04 +1000 | [diff] [blame] | 159 | EXPORT_SYMBOL(radix_tree_preload); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 161 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
| 162 | int offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | { |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 164 | __set_bit(offset, node->tags[tag]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |
| 166 | |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 167 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
| 168 | int offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | { |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 170 | __clear_bit(offset, node->tags[tag]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | } |
| 172 | |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 173 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
| 174 | int offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | { |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 176 | return test_bit(offset, node->tags[tag]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | } |
| 178 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 179 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
| 180 | { |
Al Viro | 20241ad | 2006-10-10 22:47:57 +0100 | [diff] [blame] | 181 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 182 | } |
| 183 | |
| 184 | |
| 185 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) |
| 186 | { |
Al Viro | 20241ad | 2006-10-10 22:47:57 +0100 | [diff] [blame] | 187 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 188 | } |
| 189 | |
| 190 | static inline void root_tag_clear_all(struct radix_tree_root *root) |
| 191 | { |
| 192 | root->gfp_mask &= __GFP_BITS_MASK; |
| 193 | } |
| 194 | |
| 195 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) |
| 196 | { |
Al Viro | 20241ad | 2006-10-10 22:47:57 +0100 | [diff] [blame] | 197 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 198 | } |
| 199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | /* |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 201 | * Returns 1 if any slot in the node has this tag set. |
| 202 | * Otherwise returns 0. |
| 203 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 204 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 205 | { |
| 206 | int idx; |
| 207 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
| 208 | if (node->tags[tag][idx]) |
| 209 | return 1; |
| 210 | } |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | * Return the maximum key which can be store into a |
| 216 | * radix tree with height HEIGHT. |
| 217 | */ |
| 218 | static inline unsigned long radix_tree_maxindex(unsigned int height) |
| 219 | { |
| 220 | return height_to_maxindex[height]; |
| 221 | } |
| 222 | |
| 223 | /* |
| 224 | * Extend a radix tree so it can store key @index. |
| 225 | */ |
| 226 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) |
| 227 | { |
| 228 | struct radix_tree_node *node; |
| 229 | unsigned int height; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | int tag; |
| 231 | |
| 232 | /* Figure out what the height should be. */ |
| 233 | height = root->height + 1; |
| 234 | while (index > radix_tree_maxindex(height)) |
| 235 | height++; |
| 236 | |
| 237 | if (root->rnode == NULL) { |
| 238 | root->height = height; |
| 239 | goto out; |
| 240 | } |
| 241 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | do { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 243 | unsigned int newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | if (!(node = radix_tree_node_alloc(root))) |
| 245 | return -ENOMEM; |
| 246 | |
| 247 | /* Increase the height. */ |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 248 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | |
| 250 | /* Propagate the aggregated tag info into the new root */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 251 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 252 | if (root_tag_get(root, tag)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | tag_set(node, tag, 0); |
| 254 | } |
| 255 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 256 | newheight = root->height+1; |
| 257 | node->height = newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | node->count = 1; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 259 | node = radix_tree_ptr_to_indirect(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 260 | rcu_assign_pointer(root->rnode, node); |
| 261 | root->height = newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | } while (height > root->height); |
| 263 | out: |
| 264 | return 0; |
| 265 | } |
| 266 | |
| 267 | /** |
| 268 | * radix_tree_insert - insert into a radix tree |
| 269 | * @root: radix tree root |
| 270 | * @index: index key |
| 271 | * @item: item to insert |
| 272 | * |
| 273 | * Insert an item into the radix tree at position @index. |
| 274 | */ |
| 275 | int radix_tree_insert(struct radix_tree_root *root, |
| 276 | unsigned long index, void *item) |
| 277 | { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 278 | struct radix_tree_node *node = NULL, *slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | unsigned int height, shift; |
| 280 | int offset; |
| 281 | int error; |
| 282 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 283 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 284 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | /* Make sure the tree is high enough. */ |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 286 | if (index > radix_tree_maxindex(root->height)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | error = radix_tree_extend(root, index); |
| 288 | if (error) |
| 289 | return error; |
| 290 | } |
| 291 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 292 | slot = radix_tree_indirect_to_ptr(root->rnode); |
| 293 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | height = root->height; |
| 295 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 296 | |
| 297 | offset = 0; /* uninitialised var warning */ |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 298 | while (height > 0) { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 299 | if (slot == NULL) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | /* Have to add a child node. */ |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 301 | if (!(slot = radix_tree_node_alloc(root))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | return -ENOMEM; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 303 | slot->height = height; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 304 | if (node) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 305 | rcu_assign_pointer(node->slots[offset], slot); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | node->count++; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 307 | } else |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 308 | rcu_assign_pointer(root->rnode, |
| 309 | radix_tree_ptr_to_indirect(slot)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | } |
| 311 | |
| 312 | /* Go a level down */ |
| 313 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 314 | node = slot; |
| 315 | slot = node->slots[offset]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | shift -= RADIX_TREE_MAP_SHIFT; |
| 317 | height--; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 318 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 320 | if (slot != NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | return -EEXIST; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 322 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 323 | if (node) { |
| 324 | node->count++; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 325 | rcu_assign_pointer(node->slots[offset], item); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 326 | BUG_ON(tag_get(node, 0, offset)); |
| 327 | BUG_ON(tag_get(node, 1, offset)); |
| 328 | } else { |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 329 | rcu_assign_pointer(root->rnode, item); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 330 | BUG_ON(root_tag_get(root, 0)); |
| 331 | BUG_ON(root_tag_get(root, 1)); |
| 332 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | return 0; |
| 335 | } |
| 336 | EXPORT_SYMBOL(radix_tree_insert); |
| 337 | |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 338 | /** |
| 339 | * radix_tree_lookup_slot - lookup a slot in a radix tree |
| 340 | * @root: radix tree root |
| 341 | * @index: index key |
| 342 | * |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 343 | * Returns: the slot corresponding to the position @index in the |
| 344 | * radix tree @root. This is useful for update-if-exists operations. |
| 345 | * |
| 346 | * This function cannot be called under rcu_read_lock, it must be |
| 347 | * excluded from writers, as must the returned slot for subsequent |
| 348 | * use by radix_tree_deref_slot() and radix_tree_replace slot. |
| 349 | * Caller must hold tree write locked across slot lookup and |
| 350 | * replace. |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 351 | */ |
| 352 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) |
| 353 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 354 | unsigned int height, shift; |
| 355 | struct radix_tree_node *node, **slot; |
| 356 | |
| 357 | node = root->rnode; |
| 358 | if (node == NULL) |
| 359 | return NULL; |
| 360 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 361 | if (!radix_tree_is_indirect_ptr(node)) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 362 | if (index > 0) |
| 363 | return NULL; |
| 364 | return (void **)&root->rnode; |
| 365 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 366 | node = radix_tree_indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 367 | |
| 368 | height = node->height; |
| 369 | if (index > radix_tree_maxindex(height)) |
| 370 | return NULL; |
| 371 | |
| 372 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 373 | |
| 374 | do { |
| 375 | slot = (struct radix_tree_node **) |
| 376 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); |
| 377 | node = *slot; |
| 378 | if (node == NULL) |
| 379 | return NULL; |
| 380 | |
| 381 | shift -= RADIX_TREE_MAP_SHIFT; |
| 382 | height--; |
| 383 | } while (height > 0); |
| 384 | |
| 385 | return (void **)slot; |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 386 | } |
| 387 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
| 388 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | /** |
| 390 | * radix_tree_lookup - perform lookup operation on a radix tree |
| 391 | * @root: radix tree root |
| 392 | * @index: index key |
| 393 | * |
| 394 | * Lookup the item at the position @index in the radix tree @root. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 395 | * |
| 396 | * This function can be called under rcu_read_lock, however the caller |
| 397 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free |
| 398 | * them safely). No RCU barriers are required to access or modify the |
| 399 | * returned item, however. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | */ |
| 401 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) |
| 402 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 403 | unsigned int height, shift; |
| 404 | struct radix_tree_node *node, **slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 406 | node = rcu_dereference(root->rnode); |
| 407 | if (node == NULL) |
| 408 | return NULL; |
| 409 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 410 | if (!radix_tree_is_indirect_ptr(node)) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 411 | if (index > 0) |
| 412 | return NULL; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 413 | return node; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 414 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 415 | node = radix_tree_indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 416 | |
| 417 | height = node->height; |
| 418 | if (index > radix_tree_maxindex(height)) |
| 419 | return NULL; |
| 420 | |
| 421 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 422 | |
| 423 | do { |
| 424 | slot = (struct radix_tree_node **) |
| 425 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); |
| 426 | node = rcu_dereference(*slot); |
| 427 | if (node == NULL) |
| 428 | return NULL; |
| 429 | |
| 430 | shift -= RADIX_TREE_MAP_SHIFT; |
| 431 | height--; |
| 432 | } while (height > 0); |
| 433 | |
| 434 | return node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | } |
| 436 | EXPORT_SYMBOL(radix_tree_lookup); |
| 437 | |
| 438 | /** |
| 439 | * radix_tree_tag_set - set a tag on a radix tree node |
| 440 | * @root: radix tree root |
| 441 | * @index: index key |
| 442 | * @tag: tag index |
| 443 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 444 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| 445 | * corresponding to @index in the radix tree. From |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | * the root all the way down to the leaf node. |
| 447 | * |
| 448 | * Returns the address of the tagged item. Setting a tag on a not-present |
| 449 | * item is a bug. |
| 450 | */ |
| 451 | void *radix_tree_tag_set(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 452 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | { |
| 454 | unsigned int height, shift; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 455 | struct radix_tree_node *slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | |
| 457 | height = root->height; |
Peter Zijlstra | 4c91c36 | 2006-06-23 02:03:25 -0700 | [diff] [blame] | 458 | BUG_ON(index > radix_tree_maxindex(height)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 460 | slot = radix_tree_indirect_to_ptr(root->rnode); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 461 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | |
| 463 | while (height > 0) { |
| 464 | int offset; |
| 465 | |
| 466 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 467 | if (!tag_get(slot, tag, offset)) |
| 468 | tag_set(slot, tag, offset); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 469 | slot = slot->slots[offset]; |
| 470 | BUG_ON(slot == NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | shift -= RADIX_TREE_MAP_SHIFT; |
| 472 | height--; |
| 473 | } |
| 474 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 475 | /* set the root's tag bit */ |
| 476 | if (slot && !root_tag_get(root, tag)) |
| 477 | root_tag_set(root, tag); |
| 478 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 479 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | } |
| 481 | EXPORT_SYMBOL(radix_tree_tag_set); |
| 482 | |
| 483 | /** |
| 484 | * radix_tree_tag_clear - clear a tag on a radix tree node |
| 485 | * @root: radix tree root |
| 486 | * @index: index key |
| 487 | * @tag: tag index |
| 488 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 489 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| 490 | * corresponding to @index in the radix tree. If |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | * this causes the leaf node to have no tags set then clear the tag in the |
| 492 | * next-to-leaf node, etc. |
| 493 | * |
| 494 | * Returns the address of the tagged item on success, else NULL. ie: |
| 495 | * has the same return value and semantics as radix_tree_lookup(). |
| 496 | */ |
| 497 | void *radix_tree_tag_clear(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 498 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 499 | { |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame^] | 500 | /* |
| 501 | * The radix tree path needs to be one longer than the maximum path |
| 502 | * since the "list" is null terminated. |
| 503 | */ |
| 504 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 505 | struct radix_tree_node *slot = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | unsigned int height, shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | |
| 508 | height = root->height; |
| 509 | if (index > radix_tree_maxindex(height)) |
| 510 | goto out; |
| 511 | |
| 512 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
| 513 | pathp->node = NULL; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 514 | slot = radix_tree_indirect_to_ptr(root->rnode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | |
| 516 | while (height > 0) { |
| 517 | int offset; |
| 518 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 519 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | goto out; |
| 521 | |
| 522 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 523 | pathp[1].offset = offset; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 524 | pathp[1].node = slot; |
| 525 | slot = slot->slots[offset]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | pathp++; |
| 527 | shift -= RADIX_TREE_MAP_SHIFT; |
| 528 | height--; |
| 529 | } |
| 530 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 531 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | goto out; |
| 533 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 534 | while (pathp->node) { |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 535 | if (!tag_get(pathp->node, tag, pathp->offset)) |
| 536 | goto out; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 537 | tag_clear(pathp->node, tag, pathp->offset); |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 538 | if (any_tag_set(pathp->node, tag)) |
| 539 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | pathp--; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 541 | } |
| 542 | |
| 543 | /* clear the root's tag bit */ |
| 544 | if (root_tag_get(root, tag)) |
| 545 | root_tag_clear(root, tag); |
| 546 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | out: |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 548 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | } |
| 550 | EXPORT_SYMBOL(radix_tree_tag_clear); |
| 551 | |
| 552 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ |
| 553 | /** |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 554 | * radix_tree_tag_get - get a tag on a radix tree node |
| 555 | * @root: radix tree root |
| 556 | * @index: index key |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 557 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | * |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 559 | * Return values: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | * |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 561 | * 0: tag not present or not set |
| 562 | * 1: tag set |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | */ |
| 564 | int radix_tree_tag_get(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 565 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | { |
| 567 | unsigned int height, shift; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 568 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | int saw_unset_tag = 0; |
| 570 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 571 | /* check the root's tag bit */ |
| 572 | if (!root_tag_get(root, tag)) |
| 573 | return 0; |
| 574 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 575 | node = rcu_dereference(root->rnode); |
| 576 | if (node == NULL) |
| 577 | return 0; |
| 578 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 579 | if (!radix_tree_is_indirect_ptr(node)) |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 580 | return (index == 0); |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 581 | node = radix_tree_indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 582 | |
| 583 | height = node->height; |
| 584 | if (index > radix_tree_maxindex(height)) |
| 585 | return 0; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 586 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | |
| 589 | for ( ; ; ) { |
| 590 | int offset; |
| 591 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 592 | if (node == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | return 0; |
| 594 | |
| 595 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 596 | |
| 597 | /* |
| 598 | * This is just a debug check. Later, we can bale as soon as |
| 599 | * we see an unset tag. |
| 600 | */ |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 601 | if (!tag_get(node, tag, offset)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | saw_unset_tag = 1; |
| 603 | if (height == 1) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 604 | int ret = tag_get(node, tag, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | |
| 606 | BUG_ON(ret && saw_unset_tag); |
Wu Fengguang | e5dcd90 | 2006-06-25 05:48:14 -0700 | [diff] [blame] | 607 | return !!ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 609 | node = rcu_dereference(node->slots[offset]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | shift -= RADIX_TREE_MAP_SHIFT; |
| 611 | height--; |
| 612 | } |
| 613 | } |
| 614 | EXPORT_SYMBOL(radix_tree_tag_get); |
| 615 | #endif |
| 616 | |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 617 | /** |
| 618 | * radix_tree_next_hole - find the next hole (not-present entry) |
| 619 | * @root: tree root |
| 620 | * @index: index key |
| 621 | * @max_scan: maximum range to search |
| 622 | * |
| 623 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest |
| 624 | * indexed hole. |
| 625 | * |
| 626 | * Returns: the index of the hole if found, otherwise returns an index |
| 627 | * outside of the set specified (in which case 'return - index >= max_scan' |
| 628 | * will be true). |
| 629 | * |
| 630 | * radix_tree_next_hole may be called under rcu_read_lock. However, like |
| 631 | * radix_tree_gang_lookup, this will not atomically search a snapshot of the |
| 632 | * tree at a single point in time. For example, if a hole is created at index |
| 633 | * 5, then subsequently a hole is created at index 10, radix_tree_next_hole |
| 634 | * covering both indexes may return 10 if called under rcu_read_lock. |
| 635 | */ |
| 636 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, |
| 637 | unsigned long index, unsigned long max_scan) |
| 638 | { |
| 639 | unsigned long i; |
| 640 | |
| 641 | for (i = 0; i < max_scan; i++) { |
| 642 | if (!radix_tree_lookup(root, index)) |
| 643 | break; |
| 644 | index++; |
| 645 | if (index == 0) |
| 646 | break; |
| 647 | } |
| 648 | |
| 649 | return index; |
| 650 | } |
| 651 | EXPORT_SYMBOL(radix_tree_next_hole); |
| 652 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | static unsigned int |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 654 | __lookup(struct radix_tree_node *slot, void **results, unsigned long index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | unsigned int max_items, unsigned long *next_index) |
| 656 | { |
| 657 | unsigned int nr_found = 0; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 658 | unsigned int shift, height; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 659 | unsigned long i; |
| 660 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 661 | height = slot->height; |
| 662 | if (height == 0) |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 663 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 666 | for ( ; height > 1; height--) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 667 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 668 | for (;;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | if (slot->slots[i] != NULL) |
| 670 | break; |
| 671 | index &= ~((1UL << shift) - 1); |
| 672 | index += 1UL << shift; |
| 673 | if (index == 0) |
| 674 | goto out; /* 32-bit wraparound */ |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 675 | i++; |
| 676 | if (i == RADIX_TREE_MAP_SIZE) |
| 677 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | shift -= RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 681 | slot = rcu_dereference(slot->slots[i]); |
| 682 | if (slot == NULL) |
| 683 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | } |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 685 | |
| 686 | /* Bottom level: grab some items */ |
| 687 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 688 | struct radix_tree_node *node; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 689 | index++; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 690 | node = slot->slots[i]; |
| 691 | if (node) { |
| 692 | results[nr_found++] = rcu_dereference(node); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 693 | if (nr_found == max_items) |
| 694 | goto out; |
| 695 | } |
| 696 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | out: |
| 698 | *next_index = index; |
| 699 | return nr_found; |
| 700 | } |
| 701 | |
| 702 | /** |
| 703 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree |
| 704 | * @root: radix tree root |
| 705 | * @results: where the results of the lookup are placed |
| 706 | * @first_index: start the lookup from this key |
| 707 | * @max_items: place up to this many items at *results |
| 708 | * |
| 709 | * Performs an index-ascending scan of the tree for present items. Places |
| 710 | * them at *@results and returns the number of items which were placed at |
| 711 | * *@results. |
| 712 | * |
| 713 | * The implementation is naive. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 714 | * |
| 715 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under |
| 716 | * rcu_read_lock. In this case, rather than the returned results being |
| 717 | * an atomic snapshot of the tree at a single point in time, the semantics |
| 718 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups |
| 719 | * have been issued in individual locks, and results stored in 'results'. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | */ |
| 721 | unsigned int |
| 722 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, |
| 723 | unsigned long first_index, unsigned int max_items) |
| 724 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 725 | unsigned long max_index; |
| 726 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | unsigned long cur_index = first_index; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 728 | unsigned int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 730 | node = rcu_dereference(root->rnode); |
| 731 | if (!node) |
| 732 | return 0; |
| 733 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 734 | if (!radix_tree_is_indirect_ptr(node)) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 735 | if (first_index > 0) |
| 736 | return 0; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 737 | results[0] = node; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 738 | return 1; |
| 739 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 740 | node = radix_tree_indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 741 | |
| 742 | max_index = radix_tree_maxindex(node->height); |
| 743 | |
| 744 | ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 745 | while (ret < max_items) { |
| 746 | unsigned int nr_found; |
| 747 | unsigned long next_index; /* Index of next search */ |
| 748 | |
| 749 | if (cur_index > max_index) |
| 750 | break; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 751 | nr_found = __lookup(node, results + ret, cur_index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | max_items - ret, &next_index); |
| 753 | ret += nr_found; |
| 754 | if (next_index == 0) |
| 755 | break; |
| 756 | cur_index = next_index; |
| 757 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 758 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | return ret; |
| 760 | } |
| 761 | EXPORT_SYMBOL(radix_tree_gang_lookup); |
| 762 | |
| 763 | /* |
| 764 | * FIXME: the two tag_get()s here should use find_next_bit() instead of |
| 765 | * open-coding the search. |
| 766 | */ |
| 767 | static unsigned int |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 768 | __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 769 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | { |
| 771 | unsigned int nr_found = 0; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 772 | unsigned int shift, height; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 774 | height = slot->height; |
| 775 | if (height == 0) |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 776 | goto out; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 777 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 778 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 779 | while (height > 0) { |
| 780 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 782 | for (;;) { |
| 783 | if (tag_get(slot, tag, i)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | index &= ~((1UL << shift) - 1); |
| 786 | index += 1UL << shift; |
| 787 | if (index == 0) |
| 788 | goto out; /* 32-bit wraparound */ |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 789 | i++; |
| 790 | if (i == RADIX_TREE_MAP_SIZE) |
| 791 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | height--; |
| 794 | if (height == 0) { /* Bottom level: grab some items */ |
| 795 | unsigned long j = index & RADIX_TREE_MAP_MASK; |
| 796 | |
| 797 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 798 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | index++; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 800 | if (!tag_get(slot, tag, j)) |
| 801 | continue; |
| 802 | node = slot->slots[j]; |
| 803 | /* |
| 804 | * Even though the tag was found set, we need to |
| 805 | * recheck that we have a non-NULL node, because |
| 806 | * if this lookup is lockless, it may have been |
| 807 | * subsequently deleted. |
| 808 | * |
| 809 | * Similar care must be taken in any place that |
| 810 | * lookup ->slots[x] without a lock (ie. can't |
| 811 | * rely on its value remaining the same). |
| 812 | */ |
| 813 | if (node) { |
| 814 | node = rcu_dereference(node); |
| 815 | results[nr_found++] = node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 816 | if (nr_found == max_items) |
| 817 | goto out; |
| 818 | } |
| 819 | } |
| 820 | } |
| 821 | shift -= RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 822 | slot = rcu_dereference(slot->slots[i]); |
| 823 | if (slot == NULL) |
| 824 | break; |
| 825 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | out: |
| 827 | *next_index = index; |
| 828 | return nr_found; |
| 829 | } |
| 830 | |
| 831 | /** |
| 832 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree |
| 833 | * based on a tag |
| 834 | * @root: radix tree root |
| 835 | * @results: where the results of the lookup are placed |
| 836 | * @first_index: start the lookup from this key |
| 837 | * @max_items: place up to this many items at *results |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 838 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | * |
| 840 | * Performs an index-ascending scan of the tree for present items which |
| 841 | * have the tag indexed by @tag set. Places the items at *@results and |
| 842 | * returns the number of items which were placed at *@results. |
| 843 | */ |
| 844 | unsigned int |
| 845 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 846 | unsigned long first_index, unsigned int max_items, |
| 847 | unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 848 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 849 | struct radix_tree_node *node; |
| 850 | unsigned long max_index; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | unsigned long cur_index = first_index; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 852 | unsigned int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 853 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 854 | /* check the root's tag bit */ |
| 855 | if (!root_tag_get(root, tag)) |
| 856 | return 0; |
| 857 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 858 | node = rcu_dereference(root->rnode); |
| 859 | if (!node) |
| 860 | return 0; |
| 861 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 862 | if (!radix_tree_is_indirect_ptr(node)) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 863 | if (first_index > 0) |
| 864 | return 0; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 865 | results[0] = node; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 866 | return 1; |
| 867 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 868 | node = radix_tree_indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 869 | |
| 870 | max_index = radix_tree_maxindex(node->height); |
| 871 | |
| 872 | ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | while (ret < max_items) { |
| 874 | unsigned int nr_found; |
| 875 | unsigned long next_index; /* Index of next search */ |
| 876 | |
| 877 | if (cur_index > max_index) |
| 878 | break; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 879 | nr_found = __lookup_tag(node, results + ret, cur_index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 880 | max_items - ret, &next_index, tag); |
| 881 | ret += nr_found; |
| 882 | if (next_index == 0) |
| 883 | break; |
| 884 | cur_index = next_index; |
| 885 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 886 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | return ret; |
| 888 | } |
| 889 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); |
| 890 | |
| 891 | /** |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 892 | * radix_tree_shrink - shrink height of a radix tree to minimal |
| 893 | * @root radix tree root |
| 894 | */ |
| 895 | static inline void radix_tree_shrink(struct radix_tree_root *root) |
| 896 | { |
| 897 | /* try to shrink tree height */ |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 898 | while (root->height > 0) { |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 899 | struct radix_tree_node *to_free = root->rnode; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 900 | void *newptr; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 901 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 902 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
| 903 | to_free = radix_tree_indirect_to_ptr(to_free); |
| 904 | |
| 905 | /* |
| 906 | * The candidate node has more than one child, or its child |
| 907 | * is not at the leftmost slot, we cannot shrink. |
| 908 | */ |
| 909 | if (to_free->count != 1) |
| 910 | break; |
| 911 | if (!to_free->slots[0]) |
| 912 | break; |
| 913 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 914 | /* |
| 915 | * We don't need rcu_assign_pointer(), since we are simply |
| 916 | * moving the node from one part of the tree to another. If |
| 917 | * it was safe to dereference the old pointer to it |
| 918 | * (to_free->slots[0]), it will be safe to dereference the new |
| 919 | * one (root->rnode). |
| 920 | */ |
| 921 | newptr = to_free->slots[0]; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 922 | if (root->height > 1) |
| 923 | newptr = radix_tree_ptr_to_indirect(newptr); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 924 | root->rnode = newptr; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 925 | root->height--; |
| 926 | /* must only free zeroed nodes into the slab */ |
| 927 | tag_clear(to_free, 0, 0); |
| 928 | tag_clear(to_free, 1, 0); |
| 929 | to_free->slots[0] = NULL; |
| 930 | to_free->count = 0; |
| 931 | radix_tree_node_free(to_free); |
| 932 | } |
| 933 | } |
| 934 | |
| 935 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | * radix_tree_delete - delete an item from a radix tree |
| 937 | * @root: radix tree root |
| 938 | * @index: index key |
| 939 | * |
| 940 | * Remove the item at @index from the radix tree rooted at @root. |
| 941 | * |
| 942 | * Returns the address of the deleted item, or NULL if it was not present. |
| 943 | */ |
| 944 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) |
| 945 | { |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame^] | 946 | /* |
| 947 | * The radix tree path needs to be one longer than the maximum path |
| 948 | * since the "list" is null terminated. |
| 949 | */ |
| 950 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 951 | struct radix_tree_node *slot = NULL; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 952 | struct radix_tree_node *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 953 | unsigned int height, shift; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 954 | int tag; |
| 955 | int offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 956 | |
| 957 | height = root->height; |
| 958 | if (index > radix_tree_maxindex(height)) |
| 959 | goto out; |
| 960 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 961 | slot = root->rnode; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 962 | if (height == 0) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 963 | root_tag_clear_all(root); |
| 964 | root->rnode = NULL; |
| 965 | goto out; |
| 966 | } |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 967 | slot = radix_tree_indirect_to_ptr(slot); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 968 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
| 970 | pathp->node = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 972 | do { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 973 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | goto out; |
| 975 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | pathp++; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 977 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 978 | pathp->offset = offset; |
| 979 | pathp->node = slot; |
| 980 | slot = slot->slots[offset]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | shift -= RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 982 | height--; |
| 983 | } while (height > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 984 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 985 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 986 | goto out; |
| 987 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 988 | /* |
| 989 | * Clear all tags associated with the just-deleted item |
| 990 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 991 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 992 | if (tag_get(pathp->node, tag, pathp->offset)) |
| 993 | radix_tree_tag_clear(root, index, tag); |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 994 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 996 | to_free = NULL; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 997 | /* Now free the nodes we do not need anymore */ |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 998 | while (pathp->node) { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 999 | pathp->node->slots[pathp->offset] = NULL; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1000 | pathp->node->count--; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1001 | /* |
| 1002 | * Queue the node for deferred freeing after the |
| 1003 | * last reference to it disappears (set NULL, above). |
| 1004 | */ |
| 1005 | if (to_free) |
| 1006 | radix_tree_node_free(to_free); |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1007 | |
| 1008 | if (pathp->node->count) { |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1009 | if (pathp->node == |
| 1010 | radix_tree_indirect_to_ptr(root->rnode)) |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1011 | radix_tree_shrink(root); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1012 | goto out; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1013 | } |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1014 | |
| 1015 | /* Node with zero slots in use so free it */ |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1016 | to_free = pathp->node; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1017 | pathp--; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1018 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1019 | } |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1020 | root_tag_clear_all(root); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1021 | root->height = 0; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1022 | root->rnode = NULL; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1023 | if (to_free) |
| 1024 | radix_tree_node_free(to_free); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1025 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | out: |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1027 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | } |
| 1029 | EXPORT_SYMBOL(radix_tree_delete); |
| 1030 | |
| 1031 | /** |
| 1032 | * radix_tree_tagged - test whether any items in the tree are tagged |
| 1033 | * @root: radix tree root |
| 1034 | * @tag: tag to test |
| 1035 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1036 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1038 | return root_tag_get(root, tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | } |
| 1040 | EXPORT_SYMBOL(radix_tree_tagged); |
| 1041 | |
| 1042 | static void |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 1043 | radix_tree_node_ctor(void *node, struct kmem_cache *cachep, unsigned long flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | { |
| 1045 | memset(node, 0, sizeof(struct radix_tree_node)); |
| 1046 | } |
| 1047 | |
| 1048 | static __init unsigned long __maxindex(unsigned int height) |
| 1049 | { |
| 1050 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; |
| 1051 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; |
| 1052 | |
| 1053 | if (tmp >= RADIX_TREE_INDEX_BITS) |
| 1054 | index = ~0UL; |
| 1055 | return index; |
| 1056 | } |
| 1057 | |
| 1058 | static __init void radix_tree_init_maxindex(void) |
| 1059 | { |
| 1060 | unsigned int i; |
| 1061 | |
| 1062 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) |
| 1063 | height_to_maxindex[i] = __maxindex(i); |
| 1064 | } |
| 1065 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | static int radix_tree_callback(struct notifier_block *nfb, |
| 1067 | unsigned long action, |
| 1068 | void *hcpu) |
| 1069 | { |
| 1070 | int cpu = (long)hcpu; |
| 1071 | struct radix_tree_preload *rtp; |
| 1072 | |
| 1073 | /* Free per-cpu pool of perloaded nodes */ |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 1074 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | rtp = &per_cpu(radix_tree_preloads, cpu); |
| 1076 | while (rtp->nr) { |
| 1077 | kmem_cache_free(radix_tree_node_cachep, |
| 1078 | rtp->nodes[rtp->nr-1]); |
| 1079 | rtp->nodes[rtp->nr-1] = NULL; |
| 1080 | rtp->nr--; |
| 1081 | } |
| 1082 | } |
| 1083 | return NOTIFY_OK; |
| 1084 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | |
| 1086 | void __init radix_tree_init(void) |
| 1087 | { |
| 1088 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
| 1089 | sizeof(struct radix_tree_node), 0, |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 1090 | SLAB_PANIC, radix_tree_node_ctor); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | radix_tree_init_maxindex(); |
| 1092 | hotcpu_notifier(radix_tree_callback, 0); |
| 1093 | } |