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 | cde5353 | 2008-07-04 09:59:22 -0700 | [diff] [blame] | 4 | * Copyright (C) 2005 SGI, Christoph Lameter |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 5 | * Copyright (C) 2006 Nick Piggin |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 6 | * Copyright (C) 2012 Konstantin Khlebnikov |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License as |
| 10 | * published by the Free Software Foundation; either version 2, or (at |
| 11 | * your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, but |
| 14 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program; if not, write to the Free Software |
| 20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 21 | */ |
| 22 | |
| 23 | #include <linux/errno.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/kernel.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 26 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/radix-tree.h> |
| 28 | #include <linux/percpu.h> |
| 29 | #include <linux/slab.h> |
| 30 | #include <linux/notifier.h> |
| 31 | #include <linux/cpu.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 35 | #include <linux/hardirq.h> /* in_interrupt() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
| 37 | |
| 38 | #ifdef __KERNEL__ |
Nick Piggin | cfd9b7d | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 39 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | #else |
| 41 | #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ |
| 42 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
| 44 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) |
| 45 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) |
| 46 | |
| 47 | #define RADIX_TREE_TAG_LONGS \ |
| 48 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) |
| 49 | |
| 50 | struct radix_tree_node { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 51 | unsigned int height; /* Height from the bottom */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | unsigned int count; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 53 | union { |
| 54 | struct radix_tree_node *parent; /* Used when ascending tree */ |
| 55 | struct rcu_head rcu_head; /* Used when freeing node */ |
| 56 | }; |
Arnd Bergmann | a111557 | 2010-02-25 23:43:52 +0100 | [diff] [blame] | 57 | void __rcu *slots[RADIX_TREE_MAP_SIZE]; |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 58 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | }; |
| 60 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame] | 62 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ |
| 63 | RADIX_TREE_MAP_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame] | 65 | /* |
| 66 | * The height_to_maxindex array needs to be one deeper than the maximum |
| 67 | * path as height 0 holds only 1 entry. |
| 68 | */ |
| 69 | 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] | 70 | |
| 71 | /* |
| 72 | * Radix tree node cache. |
| 73 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 74 | static struct kmem_cache *radix_tree_node_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | |
| 76 | /* |
Nick Piggin | 5536805 | 2012-05-29 15:07:34 -0700 | [diff] [blame] | 77 | * The radix tree is variable-height, so an insert operation not only has |
| 78 | * to build the branch to its corresponding item, it also has to build the |
| 79 | * branch to existing items if the size has to be increased (by |
| 80 | * radix_tree_extend). |
| 81 | * |
| 82 | * The worst case is a zero height tree with just a single item at index 0, |
| 83 | * and then inserting an item at index ULONG_MAX. This requires 2 new branches |
| 84 | * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. |
| 85 | * Hence: |
| 86 | */ |
| 87 | #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) |
| 88 | |
| 89 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | * Per-cpu pool of preloaded nodes |
| 91 | */ |
| 92 | struct radix_tree_preload { |
| 93 | int nr; |
Nick Piggin | 5536805 | 2012-05-29 15:07:34 -0700 | [diff] [blame] | 94 | struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | }; |
Harvey Harrison | 8cef7d5 | 2009-01-06 14:40:50 -0800 | [diff] [blame] | 96 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 98 | static inline void *ptr_to_indirect(void *ptr) |
| 99 | { |
| 100 | return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR); |
| 101 | } |
| 102 | |
| 103 | static inline void *indirect_to_ptr(void *ptr) |
| 104 | { |
| 105 | return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); |
| 106 | } |
| 107 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 108 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
| 109 | { |
| 110 | return root->gfp_mask & __GFP_BITS_MASK; |
| 111 | } |
| 112 | |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 113 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
| 114 | int offset) |
| 115 | { |
| 116 | __set_bit(offset, node->tags[tag]); |
| 117 | } |
| 118 | |
| 119 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
| 120 | int offset) |
| 121 | { |
| 122 | __clear_bit(offset, node->tags[tag]); |
| 123 | } |
| 124 | |
| 125 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
| 126 | int offset) |
| 127 | { |
| 128 | return test_bit(offset, node->tags[tag]); |
| 129 | } |
| 130 | |
| 131 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
| 132 | { |
| 133 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
| 134 | } |
| 135 | |
| 136 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) |
| 137 | { |
| 138 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
| 139 | } |
| 140 | |
| 141 | static inline void root_tag_clear_all(struct radix_tree_root *root) |
| 142 | { |
| 143 | root->gfp_mask &= __GFP_BITS_MASK; |
| 144 | } |
| 145 | |
| 146 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) |
| 147 | { |
| 148 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * Returns 1 if any slot in the node has this tag set. |
| 153 | * Otherwise returns 0. |
| 154 | */ |
| 155 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
| 156 | { |
| 157 | int idx; |
| 158 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
| 159 | if (node->tags[tag][idx]) |
| 160 | return 1; |
| 161 | } |
| 162 | return 0; |
| 163 | } |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 164 | |
| 165 | /** |
| 166 | * radix_tree_find_next_bit - find the next set bit in a memory region |
| 167 | * |
| 168 | * @addr: The address to base the search on |
| 169 | * @size: The bitmap size in bits |
| 170 | * @offset: The bitnumber to start searching at |
| 171 | * |
| 172 | * Unrollable variant of find_next_bit() for constant size arrays. |
| 173 | * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. |
| 174 | * Returns next bit offset, or size if nothing found. |
| 175 | */ |
| 176 | static __always_inline unsigned long |
| 177 | radix_tree_find_next_bit(const unsigned long *addr, |
| 178 | unsigned long size, unsigned long offset) |
| 179 | { |
| 180 | if (!__builtin_constant_p(size)) |
| 181 | return find_next_bit(addr, size, offset); |
| 182 | |
| 183 | if (offset < size) { |
| 184 | unsigned long tmp; |
| 185 | |
| 186 | addr += offset / BITS_PER_LONG; |
| 187 | tmp = *addr >> (offset % BITS_PER_LONG); |
| 188 | if (tmp) |
| 189 | return __ffs(tmp) + offset; |
| 190 | offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); |
| 191 | while (offset < size) { |
| 192 | tmp = *++addr; |
| 193 | if (tmp) |
| 194 | return __ffs(tmp) + offset; |
| 195 | offset += BITS_PER_LONG; |
| 196 | } |
| 197 | } |
| 198 | return size; |
| 199 | } |
| 200 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | /* |
| 202 | * This assumes that the caller has performed appropriate preallocation, and |
| 203 | * that the caller has pinned this thread of control to the current CPU. |
| 204 | */ |
| 205 | static struct radix_tree_node * |
| 206 | radix_tree_node_alloc(struct radix_tree_root *root) |
| 207 | { |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 208 | struct radix_tree_node *ret = NULL; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 209 | gfp_t gfp_mask = root_gfp_mask(root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 211 | /* |
| 212 | * Preload code isn't irq safe and it doesn't make sence to use |
| 213 | * preloading in the interrupt anyway as all the allocations have to |
| 214 | * be atomic. So just do normal allocation when in interrupt. |
| 215 | */ |
| 216 | if (!(gfp_mask & __GFP_WAIT) && !in_interrupt()) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | struct radix_tree_preload *rtp; |
| 218 | |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 219 | /* |
| 220 | * Provided the caller has preloaded here, we will always |
| 221 | * succeed in getting a node here (and never reach |
| 222 | * kmem_cache_alloc) |
| 223 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 225 | if (rtp->nr) { |
| 226 | ret = rtp->nodes[rtp->nr - 1]; |
| 227 | rtp->nodes[rtp->nr - 1] = NULL; |
| 228 | rtp->nr--; |
| 229 | } |
| 230 | } |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 231 | if (ret == NULL) |
Christoph Lameter | 488514d | 2008-04-28 02:12:05 -0700 | [diff] [blame] | 232 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 233 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 234 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | return ret; |
| 236 | } |
| 237 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 238 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
| 239 | { |
| 240 | struct radix_tree_node *node = |
| 241 | container_of(head, struct radix_tree_node, rcu_head); |
Dave Chinner | b6dd086 | 2010-08-23 10:33:19 +1000 | [diff] [blame] | 242 | int i; |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 243 | |
| 244 | /* |
| 245 | * must only free zeroed nodes into the slab. radix_tree_shrink |
| 246 | * can leave us with a non-NULL entry in the first slot, so clear |
| 247 | * that here to make sure. |
| 248 | */ |
Dave Chinner | b6dd086 | 2010-08-23 10:33:19 +1000 | [diff] [blame] | 249 | for (i = 0; i < RADIX_TREE_MAX_TAGS; i++) |
| 250 | tag_clear(node, i, 0); |
| 251 | |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 252 | node->slots[0] = NULL; |
| 253 | node->count = 0; |
| 254 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 255 | kmem_cache_free(radix_tree_node_cachep, node); |
| 256 | } |
| 257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | static inline void |
| 259 | radix_tree_node_free(struct radix_tree_node *node) |
| 260 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 261 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | } |
| 263 | |
| 264 | /* |
| 265 | * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| 266 | * ensure that the addition of a single element in the tree cannot fail. On |
| 267 | * success, return zero, with preemption disabled. On error, return -ENOMEM |
| 268 | * with preemption not disabled. |
David Howells | b34df79 | 2009-11-19 18:11:14 +0000 | [diff] [blame] | 269 | * |
| 270 | * To make use of this facility, the radix tree must be initialised without |
| 271 | * __GFP_WAIT being passed to INIT_RADIX_TREE(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | */ |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 273 | static int __radix_tree_preload(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | { |
| 275 | struct radix_tree_preload *rtp; |
| 276 | struct radix_tree_node *node; |
| 277 | int ret = -ENOMEM; |
| 278 | |
| 279 | preempt_disable(); |
| 280 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 281 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { |
| 282 | preempt_enable(); |
Christoph Lameter | 488514d | 2008-04-28 02:12:05 -0700 | [diff] [blame] | 283 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | if (node == NULL) |
| 285 | goto out; |
| 286 | preempt_disable(); |
| 287 | rtp = &__get_cpu_var(radix_tree_preloads); |
| 288 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) |
| 289 | rtp->nodes[rtp->nr++] = node; |
| 290 | else |
| 291 | kmem_cache_free(radix_tree_node_cachep, node); |
| 292 | } |
| 293 | ret = 0; |
| 294 | out: |
| 295 | return ret; |
| 296 | } |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 297 | |
| 298 | /* |
| 299 | * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| 300 | * ensure that the addition of a single element in the tree cannot fail. On |
| 301 | * success, return zero, with preemption disabled. On error, return -ENOMEM |
| 302 | * with preemption not disabled. |
| 303 | * |
| 304 | * To make use of this facility, the radix tree must be initialised without |
| 305 | * __GFP_WAIT being passed to INIT_RADIX_TREE(). |
| 306 | */ |
| 307 | int radix_tree_preload(gfp_t gfp_mask) |
| 308 | { |
| 309 | /* Warn on non-sensical use... */ |
| 310 | WARN_ON_ONCE(!(gfp_mask & __GFP_WAIT)); |
| 311 | return __radix_tree_preload(gfp_mask); |
| 312 | } |
David Chinner | d7f0923 | 2007-07-14 16:05:04 +1000 | [diff] [blame] | 313 | EXPORT_SYMBOL(radix_tree_preload); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 315 | /* |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 316 | * The same as above function, except we don't guarantee preloading happens. |
| 317 | * We do it, if we decide it helps. On success, return zero with preemption |
| 318 | * disabled. On error, return -ENOMEM with preemption not disabled. |
| 319 | */ |
| 320 | int radix_tree_maybe_preload(gfp_t gfp_mask) |
| 321 | { |
| 322 | if (gfp_mask & __GFP_WAIT) |
| 323 | return __radix_tree_preload(gfp_mask); |
| 324 | /* Preloading doesn't help anything with this gfp mask, skip it */ |
| 325 | preempt_disable(); |
| 326 | return 0; |
| 327 | } |
| 328 | EXPORT_SYMBOL(radix_tree_maybe_preload); |
| 329 | |
| 330 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | * Return the maximum key which can be store into a |
| 332 | * radix tree with height HEIGHT. |
| 333 | */ |
| 334 | static inline unsigned long radix_tree_maxindex(unsigned int height) |
| 335 | { |
| 336 | return height_to_maxindex[height]; |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Extend a radix tree so it can store key @index. |
| 341 | */ |
| 342 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) |
| 343 | { |
| 344 | struct radix_tree_node *node; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 345 | struct radix_tree_node *slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | unsigned int height; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | int tag; |
| 348 | |
| 349 | /* Figure out what the height should be. */ |
| 350 | height = root->height + 1; |
| 351 | while (index > radix_tree_maxindex(height)) |
| 352 | height++; |
| 353 | |
| 354 | if (root->rnode == NULL) { |
| 355 | root->height = height; |
| 356 | goto out; |
| 357 | } |
| 358 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | do { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 360 | unsigned int newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | if (!(node = radix_tree_node_alloc(root))) |
| 362 | return -ENOMEM; |
| 363 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | /* Propagate the aggregated tag info into the new root */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 365 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 366 | if (root_tag_get(root, tag)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | tag_set(node, tag, 0); |
| 368 | } |
| 369 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 370 | /* Increase the height. */ |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 371 | newheight = root->height+1; |
| 372 | node->height = newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | node->count = 1; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 374 | node->parent = NULL; |
| 375 | slot = root->rnode; |
| 376 | if (newheight > 1) { |
| 377 | slot = indirect_to_ptr(slot); |
| 378 | slot->parent = node; |
| 379 | } |
| 380 | node->slots[0] = slot; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 381 | node = ptr_to_indirect(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 382 | rcu_assign_pointer(root->rnode, node); |
| 383 | root->height = newheight; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } while (height > root->height); |
| 385 | out: |
| 386 | return 0; |
| 387 | } |
| 388 | |
| 389 | /** |
| 390 | * radix_tree_insert - insert into a radix tree |
| 391 | * @root: radix tree root |
| 392 | * @index: index key |
| 393 | * @item: item to insert |
| 394 | * |
| 395 | * Insert an item into the radix tree at position @index. |
| 396 | */ |
| 397 | int radix_tree_insert(struct radix_tree_root *root, |
| 398 | unsigned long index, void *item) |
| 399 | { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 400 | struct radix_tree_node *node = NULL, *slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | unsigned int height, shift; |
| 402 | int offset; |
| 403 | int error; |
| 404 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 405 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 406 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | /* Make sure the tree is high enough. */ |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 408 | if (index > radix_tree_maxindex(root->height)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | error = radix_tree_extend(root, index); |
| 410 | if (error) |
| 411 | return error; |
| 412 | } |
| 413 | |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 414 | slot = indirect_to_ptr(root->rnode); |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 415 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | height = root->height; |
| 417 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 418 | |
| 419 | offset = 0; /* uninitialised var warning */ |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 420 | while (height > 0) { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 421 | if (slot == NULL) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | /* Have to add a child node. */ |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 423 | if (!(slot = radix_tree_node_alloc(root))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | return -ENOMEM; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 425 | slot->height = height; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 426 | slot->parent = node; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 427 | if (node) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 428 | rcu_assign_pointer(node->slots[offset], slot); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | node->count++; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 430 | } else |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 431 | rcu_assign_pointer(root->rnode, ptr_to_indirect(slot)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | } |
| 433 | |
| 434 | /* Go a level down */ |
| 435 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 436 | node = slot; |
| 437 | slot = node->slots[offset]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | shift -= RADIX_TREE_MAP_SHIFT; |
| 439 | height--; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 440 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 442 | if (slot != NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | return -EEXIST; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 444 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 445 | if (node) { |
| 446 | node->count++; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 447 | rcu_assign_pointer(node->slots[offset], item); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 448 | BUG_ON(tag_get(node, 0, offset)); |
| 449 | BUG_ON(tag_get(node, 1, offset)); |
| 450 | } else { |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 451 | rcu_assign_pointer(root->rnode, item); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 452 | BUG_ON(root_tag_get(root, 0)); |
| 453 | BUG_ON(root_tag_get(root, 1)); |
| 454 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | return 0; |
| 457 | } |
| 458 | EXPORT_SYMBOL(radix_tree_insert); |
| 459 | |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 460 | /* |
| 461 | * is_slot == 1 : search for the slot. |
| 462 | * is_slot == 0 : search for the node. |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 463 | */ |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 464 | static void *radix_tree_lookup_element(struct radix_tree_root *root, |
| 465 | unsigned long index, int is_slot) |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 466 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 467 | unsigned int height, shift; |
| 468 | struct radix_tree_node *node, **slot; |
| 469 | |
Paul E. McKenney | 2676a58 | 2010-02-22 17:04:54 -0800 | [diff] [blame] | 470 | node = rcu_dereference_raw(root->rnode); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 471 | if (node == NULL) |
| 472 | return NULL; |
| 473 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 474 | if (!radix_tree_is_indirect_ptr(node)) { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 475 | if (index > 0) |
| 476 | return NULL; |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 477 | return is_slot ? (void *)&root->rnode : node; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 478 | } |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 479 | node = indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 480 | |
| 481 | height = node->height; |
| 482 | if (index > radix_tree_maxindex(height)) |
| 483 | return NULL; |
| 484 | |
| 485 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 486 | |
| 487 | do { |
| 488 | slot = (struct radix_tree_node **) |
| 489 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); |
Paul E. McKenney | 2676a58 | 2010-02-22 17:04:54 -0800 | [diff] [blame] | 490 | node = rcu_dereference_raw(*slot); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 491 | if (node == NULL) |
| 492 | return NULL; |
| 493 | |
| 494 | shift -= RADIX_TREE_MAP_SHIFT; |
| 495 | height--; |
| 496 | } while (height > 0); |
| 497 | |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 498 | return is_slot ? (void *)slot : indirect_to_ptr(node); |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 499 | } |
| 500 | |
| 501 | /** |
| 502 | * radix_tree_lookup_slot - lookup a slot in a radix tree |
| 503 | * @root: radix tree root |
| 504 | * @index: index key |
| 505 | * |
| 506 | * Returns: the slot corresponding to the position @index in the |
| 507 | * radix tree @root. This is useful for update-if-exists operations. |
| 508 | * |
| 509 | * This function can be called under rcu_read_lock iff the slot is not |
| 510 | * modified by radix_tree_replace_slot, otherwise it must be called |
| 511 | * exclusive from other writers. Any dereference of the slot must be done |
| 512 | * using radix_tree_deref_slot. |
| 513 | */ |
| 514 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) |
| 515 | { |
| 516 | return (void **)radix_tree_lookup_element(root, index, 1); |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 517 | } |
| 518 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
| 519 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | /** |
| 521 | * radix_tree_lookup - perform lookup operation on a radix tree |
| 522 | * @root: radix tree root |
| 523 | * @index: index key |
| 524 | * |
| 525 | * Lookup the item at the position @index in the radix tree @root. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 526 | * |
| 527 | * This function can be called under rcu_read_lock, however the caller |
| 528 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free |
| 529 | * them safely). No RCU barriers are required to access or modify the |
| 530 | * returned item, however. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | */ |
| 532 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) |
| 533 | { |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 534 | return radix_tree_lookup_element(root, index, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | } |
| 536 | EXPORT_SYMBOL(radix_tree_lookup); |
| 537 | |
| 538 | /** |
| 539 | * radix_tree_tag_set - set a tag on a radix tree node |
| 540 | * @root: radix tree root |
| 541 | * @index: index key |
| 542 | * @tag: tag index |
| 543 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 544 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| 545 | * corresponding to @index in the radix tree. From |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | * the root all the way down to the leaf node. |
| 547 | * |
| 548 | * Returns the address of the tagged item. Setting a tag on a not-present |
| 549 | * item is a bug. |
| 550 | */ |
| 551 | void *radix_tree_tag_set(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 552 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | { |
| 554 | unsigned int height, shift; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 555 | struct radix_tree_node *slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | |
| 557 | height = root->height; |
Peter Zijlstra | 4c91c36 | 2006-06-23 02:03:25 -0700 | [diff] [blame] | 558 | BUG_ON(index > radix_tree_maxindex(height)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 560 | slot = indirect_to_ptr(root->rnode); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 561 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | |
| 563 | while (height > 0) { |
| 564 | int offset; |
| 565 | |
| 566 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 567 | if (!tag_get(slot, tag, offset)) |
| 568 | tag_set(slot, tag, offset); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 569 | slot = slot->slots[offset]; |
| 570 | BUG_ON(slot == NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | shift -= RADIX_TREE_MAP_SHIFT; |
| 572 | height--; |
| 573 | } |
| 574 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 575 | /* set the root's tag bit */ |
| 576 | if (slot && !root_tag_get(root, tag)) |
| 577 | root_tag_set(root, tag); |
| 578 | |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 579 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | } |
| 581 | EXPORT_SYMBOL(radix_tree_tag_set); |
| 582 | |
| 583 | /** |
| 584 | * radix_tree_tag_clear - clear a tag on a radix tree node |
| 585 | * @root: radix tree root |
| 586 | * @index: index key |
| 587 | * @tag: tag index |
| 588 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 589 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| 590 | * corresponding to @index in the radix tree. If |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | * this causes the leaf node to have no tags set then clear the tag in the |
| 592 | * next-to-leaf node, etc. |
| 593 | * |
| 594 | * Returns the address of the tagged item on success, else NULL. ie: |
| 595 | * has the same return value and semantics as radix_tree_lookup(). |
| 596 | */ |
| 597 | void *radix_tree_tag_clear(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 598 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | { |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 600 | struct radix_tree_node *node = NULL; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 601 | struct radix_tree_node *slot = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | unsigned int height, shift; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 603 | int uninitialized_var(offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | |
| 605 | height = root->height; |
| 606 | if (index > radix_tree_maxindex(height)) |
| 607 | goto out; |
| 608 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 609 | shift = height * RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 610 | slot = indirect_to_ptr(root->rnode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 612 | while (shift) { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 613 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | goto out; |
| 615 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | shift -= RADIX_TREE_MAP_SHIFT; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 617 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 618 | node = slot; |
| 619 | slot = slot->slots[offset]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | } |
| 621 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 622 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | goto out; |
| 624 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 625 | while (node) { |
| 626 | if (!tag_get(node, tag, offset)) |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 627 | goto out; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 628 | tag_clear(node, tag, offset); |
| 629 | if (any_tag_set(node, tag)) |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 630 | goto out; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 631 | |
| 632 | index >>= RADIX_TREE_MAP_SHIFT; |
| 633 | offset = index & RADIX_TREE_MAP_MASK; |
| 634 | node = node->parent; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 635 | } |
| 636 | |
| 637 | /* clear the root's tag bit */ |
| 638 | if (root_tag_get(root, tag)) |
| 639 | root_tag_clear(root, tag); |
| 640 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | out: |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 642 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | } |
| 644 | EXPORT_SYMBOL(radix_tree_tag_clear); |
| 645 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | /** |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 647 | * radix_tree_tag_get - get a tag on a radix tree node |
| 648 | * @root: radix tree root |
| 649 | * @index: index key |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 650 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | * |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 652 | * Return values: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | * |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 654 | * 0: tag not present or not set |
| 655 | * 1: tag set |
David Howells | ce82653 | 2010-04-06 22:36:20 +0100 | [diff] [blame] | 656 | * |
| 657 | * Note that the return value of this function may not be relied on, even if |
| 658 | * the RCU lock is held, unless tag modification and node deletion are excluded |
| 659 | * from concurrency. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | */ |
| 661 | int radix_tree_tag_get(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 662 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | { |
| 664 | unsigned int height, shift; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 665 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 667 | /* check the root's tag bit */ |
| 668 | if (!root_tag_get(root, tag)) |
| 669 | return 0; |
| 670 | |
Paul E. McKenney | 2676a58 | 2010-02-22 17:04:54 -0800 | [diff] [blame] | 671 | node = rcu_dereference_raw(root->rnode); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 672 | if (node == NULL) |
| 673 | return 0; |
| 674 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 675 | if (!radix_tree_is_indirect_ptr(node)) |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 676 | return (index == 0); |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 677 | node = indirect_to_ptr(node); |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 678 | |
| 679 | height = node->height; |
| 680 | if (index > radix_tree_maxindex(height)) |
| 681 | return 0; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 682 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | |
| 685 | for ( ; ; ) { |
| 686 | int offset; |
| 687 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 688 | if (node == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 689 | return 0; |
| 690 | |
| 691 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 692 | if (!tag_get(node, tag, offset)) |
Hugh Dickins | 3fa36ac | 2011-10-31 17:07:02 -0700 | [diff] [blame] | 693 | return 0; |
David Howells | ce82653 | 2010-04-06 22:36:20 +0100 | [diff] [blame] | 694 | if (height == 1) |
Hugh Dickins | 3fa36ac | 2011-10-31 17:07:02 -0700 | [diff] [blame] | 695 | return 1; |
Paul E. McKenney | 2676a58 | 2010-02-22 17:04:54 -0800 | [diff] [blame] | 696 | node = rcu_dereference_raw(node->slots[offset]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | shift -= RADIX_TREE_MAP_SHIFT; |
| 698 | height--; |
| 699 | } |
| 700 | } |
| 701 | EXPORT_SYMBOL(radix_tree_tag_get); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 703 | /** |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 704 | * radix_tree_next_chunk - find next chunk of slots for iteration |
| 705 | * |
| 706 | * @root: radix tree root |
| 707 | * @iter: iterator state |
| 708 | * @flags: RADIX_TREE_ITER_* flags and tag index |
| 709 | * Returns: pointer to chunk first slot, or NULL if iteration is over |
| 710 | */ |
| 711 | void **radix_tree_next_chunk(struct radix_tree_root *root, |
| 712 | struct radix_tree_iter *iter, unsigned flags) |
| 713 | { |
| 714 | unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK; |
| 715 | struct radix_tree_node *rnode, *node; |
| 716 | unsigned long index, offset; |
| 717 | |
| 718 | if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) |
| 719 | return NULL; |
| 720 | |
| 721 | /* |
| 722 | * Catch next_index overflow after ~0UL. iter->index never overflows |
| 723 | * during iterating; it can be zero only at the beginning. |
| 724 | * And we cannot overflow iter->next_index in a single step, |
| 725 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. |
Konstantin Khlebnikov | fffaee3 | 2012-06-05 21:36:33 +0400 | [diff] [blame] | 726 | * |
| 727 | * This condition also used by radix_tree_next_slot() to stop |
| 728 | * contiguous iterating, and forbid swithing to the next chunk. |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 729 | */ |
| 730 | index = iter->next_index; |
| 731 | if (!index && iter->index) |
| 732 | return NULL; |
| 733 | |
| 734 | rnode = rcu_dereference_raw(root->rnode); |
| 735 | if (radix_tree_is_indirect_ptr(rnode)) { |
| 736 | rnode = indirect_to_ptr(rnode); |
| 737 | } else if (rnode && !index) { |
| 738 | /* Single-slot tree */ |
| 739 | iter->index = 0; |
| 740 | iter->next_index = 1; |
| 741 | iter->tags = 1; |
| 742 | return (void **)&root->rnode; |
| 743 | } else |
| 744 | return NULL; |
| 745 | |
| 746 | restart: |
| 747 | shift = (rnode->height - 1) * RADIX_TREE_MAP_SHIFT; |
| 748 | offset = index >> shift; |
| 749 | |
| 750 | /* Index outside of the tree */ |
| 751 | if (offset >= RADIX_TREE_MAP_SIZE) |
| 752 | return NULL; |
| 753 | |
| 754 | node = rnode; |
| 755 | while (1) { |
| 756 | if ((flags & RADIX_TREE_ITER_TAGGED) ? |
| 757 | !test_bit(offset, node->tags[tag]) : |
| 758 | !node->slots[offset]) { |
| 759 | /* Hole detected */ |
| 760 | if (flags & RADIX_TREE_ITER_CONTIG) |
| 761 | return NULL; |
| 762 | |
| 763 | if (flags & RADIX_TREE_ITER_TAGGED) |
| 764 | offset = radix_tree_find_next_bit( |
| 765 | node->tags[tag], |
| 766 | RADIX_TREE_MAP_SIZE, |
| 767 | offset + 1); |
| 768 | else |
| 769 | while (++offset < RADIX_TREE_MAP_SIZE) { |
| 770 | if (node->slots[offset]) |
| 771 | break; |
| 772 | } |
| 773 | index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1); |
| 774 | index += offset << shift; |
| 775 | /* Overflow after ~0UL */ |
| 776 | if (!index) |
| 777 | return NULL; |
| 778 | if (offset == RADIX_TREE_MAP_SIZE) |
| 779 | goto restart; |
| 780 | } |
| 781 | |
| 782 | /* This is leaf-node */ |
| 783 | if (!shift) |
| 784 | break; |
| 785 | |
| 786 | node = rcu_dereference_raw(node->slots[offset]); |
| 787 | if (node == NULL) |
| 788 | goto restart; |
| 789 | shift -= RADIX_TREE_MAP_SHIFT; |
| 790 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 791 | } |
| 792 | |
| 793 | /* Update the iterator state */ |
| 794 | iter->index = index; |
| 795 | iter->next_index = (index | RADIX_TREE_MAP_MASK) + 1; |
| 796 | |
| 797 | /* Construct iter->tags bit-mask from node->tags[tag] array */ |
| 798 | if (flags & RADIX_TREE_ITER_TAGGED) { |
| 799 | unsigned tag_long, tag_bit; |
| 800 | |
| 801 | tag_long = offset / BITS_PER_LONG; |
| 802 | tag_bit = offset % BITS_PER_LONG; |
| 803 | iter->tags = node->tags[tag][tag_long] >> tag_bit; |
| 804 | /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ |
| 805 | if (tag_long < RADIX_TREE_TAG_LONGS - 1) { |
| 806 | /* Pick tags from next element */ |
| 807 | if (tag_bit) |
| 808 | iter->tags |= node->tags[tag][tag_long + 1] << |
| 809 | (BITS_PER_LONG - tag_bit); |
| 810 | /* Clip chunk size, here only BITS_PER_LONG tags */ |
| 811 | iter->next_index = index + BITS_PER_LONG; |
| 812 | } |
| 813 | } |
| 814 | |
| 815 | return node->slots + offset; |
| 816 | } |
| 817 | EXPORT_SYMBOL(radix_tree_next_chunk); |
| 818 | |
| 819 | /** |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 820 | * radix_tree_range_tag_if_tagged - for each item in given range set given |
| 821 | * tag if item has another tag set |
| 822 | * @root: radix tree root |
| 823 | * @first_indexp: pointer to a starting index of a range to scan |
| 824 | * @last_index: last index of a range to scan |
| 825 | * @nr_to_tag: maximum number items to tag |
| 826 | * @iftag: tag index to test |
| 827 | * @settag: tag index to set if tested tag is set |
| 828 | * |
| 829 | * This function scans range of radix tree from first_index to last_index |
| 830 | * (inclusive). For each item in the range if iftag is set, the function sets |
| 831 | * also settag. The function stops either after tagging nr_to_tag items or |
| 832 | * after reaching last_index. |
| 833 | * |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 834 | * The tags must be set from the leaf level only and propagated back up the |
| 835 | * path to the root. We must do this so that we resolve the full path before |
| 836 | * setting any tags on intermediate nodes. If we set tags as we descend, then |
| 837 | * we can get to the leaf node and find that the index that has the iftag |
| 838 | * set is outside the range we are scanning. This reults in dangling tags and |
| 839 | * can lead to problems with later tag operations (e.g. livelocks on lookups). |
| 840 | * |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 841 | * The function returns number of leaves where the tag was set and sets |
| 842 | * *first_indexp to the first unscanned index. |
Jan Kara | d5ed3a4 | 2010-08-19 14:13:33 -0700 | [diff] [blame] | 843 | * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must |
| 844 | * be prepared to handle that. |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 845 | */ |
| 846 | unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, |
| 847 | unsigned long *first_indexp, unsigned long last_index, |
| 848 | unsigned long nr_to_tag, |
| 849 | unsigned int iftag, unsigned int settag) |
| 850 | { |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 851 | unsigned int height = root->height; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 852 | struct radix_tree_node *node = NULL; |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 853 | struct radix_tree_node *slot; |
| 854 | unsigned int shift; |
| 855 | unsigned long tagged = 0; |
| 856 | unsigned long index = *first_indexp; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 857 | |
| 858 | last_index = min(last_index, radix_tree_maxindex(height)); |
| 859 | if (index > last_index) |
| 860 | return 0; |
| 861 | if (!nr_to_tag) |
| 862 | return 0; |
| 863 | if (!root_tag_get(root, iftag)) { |
| 864 | *first_indexp = last_index + 1; |
| 865 | return 0; |
| 866 | } |
| 867 | if (height == 0) { |
| 868 | *first_indexp = last_index + 1; |
| 869 | root_tag_set(root, settag); |
| 870 | return 1; |
| 871 | } |
| 872 | |
| 873 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 874 | slot = indirect_to_ptr(root->rnode); |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 875 | |
| 876 | for (;;) { |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 877 | unsigned long upindex; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 878 | int offset; |
| 879 | |
| 880 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 881 | if (!slot->slots[offset]) |
| 882 | goto next; |
| 883 | if (!tag_get(slot, iftag, offset)) |
| 884 | goto next; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 885 | if (shift) { |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 886 | /* Go down one level */ |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 887 | shift -= RADIX_TREE_MAP_SHIFT; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 888 | node = slot; |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 889 | slot = slot->slots[offset]; |
| 890 | continue; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 891 | } |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 892 | |
| 893 | /* tag the leaf */ |
| 894 | tagged++; |
| 895 | tag_set(slot, settag, offset); |
| 896 | |
| 897 | /* walk back up the path tagging interior nodes */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 898 | upindex = index; |
| 899 | while (node) { |
| 900 | upindex >>= RADIX_TREE_MAP_SHIFT; |
| 901 | offset = upindex & RADIX_TREE_MAP_MASK; |
| 902 | |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 903 | /* stop if we find a node with the tag already set */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 904 | if (tag_get(node, settag, offset)) |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 905 | break; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 906 | tag_set(node, settag, offset); |
| 907 | node = node->parent; |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 908 | } |
| 909 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 910 | /* |
| 911 | * Small optimization: now clear that node pointer. |
| 912 | * Since all of this slot's ancestors now have the tag set |
| 913 | * from setting it above, we have no further need to walk |
| 914 | * back up the tree setting tags, until we update slot to |
| 915 | * point to another radix_tree_node. |
| 916 | */ |
| 917 | node = NULL; |
| 918 | |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 919 | next: |
| 920 | /* Go to next item at level determined by 'shift' */ |
| 921 | index = ((index >> shift) + 1) << shift; |
Jan Kara | d5ed3a4 | 2010-08-19 14:13:33 -0700 | [diff] [blame] | 922 | /* Overflow can happen when last_index is ~0UL... */ |
| 923 | if (index > last_index || !index) |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 924 | break; |
| 925 | if (tagged >= nr_to_tag) |
| 926 | break; |
| 927 | while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) { |
| 928 | /* |
| 929 | * We've fully scanned this node. Go up. Because |
| 930 | * last_index is guaranteed to be in the tree, what |
| 931 | * we do below cannot wander astray. |
| 932 | */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 933 | slot = slot->parent; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 934 | shift += RADIX_TREE_MAP_SHIFT; |
| 935 | } |
| 936 | } |
| 937 | /* |
Toshiyuki Okajima | ac15ee6 | 2011-01-25 15:07:32 -0800 | [diff] [blame] | 938 | * We need not to tag the root tag if there is no tag which is set with |
| 939 | * settag within the range from *first_indexp to last_index. |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 940 | */ |
Toshiyuki Okajima | ac15ee6 | 2011-01-25 15:07:32 -0800 | [diff] [blame] | 941 | if (tagged > 0) |
| 942 | root_tag_set(root, settag); |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 943 | *first_indexp = index; |
| 944 | |
| 945 | return tagged; |
| 946 | } |
| 947 | EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); |
| 948 | |
| 949 | |
| 950 | /** |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 951 | * radix_tree_next_hole - find the next hole (not-present entry) |
| 952 | * @root: tree root |
| 953 | * @index: index key |
| 954 | * @max_scan: maximum range to search |
| 955 | * |
| 956 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest |
| 957 | * indexed hole. |
| 958 | * |
| 959 | * Returns: the index of the hole if found, otherwise returns an index |
| 960 | * outside of the set specified (in which case 'return - index >= max_scan' |
Wu Fengguang | 8e6bdb7 | 2008-11-27 11:42:22 +0100 | [diff] [blame] | 961 | * will be true). In rare cases of index wrap-around, 0 will be returned. |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 962 | * |
| 963 | * radix_tree_next_hole may be called under rcu_read_lock. However, like |
Wu Fengguang | 8e6bdb7 | 2008-11-27 11:42:22 +0100 | [diff] [blame] | 964 | * radix_tree_gang_lookup, this will not atomically search a snapshot of |
| 965 | * the tree at a single point in time. For example, if a hole is created |
| 966 | * at index 5, then subsequently a hole is created at index 10, |
| 967 | * radix_tree_next_hole covering both indexes may return 10 if called |
| 968 | * under rcu_read_lock. |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 969 | */ |
| 970 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, |
| 971 | unsigned long index, unsigned long max_scan) |
| 972 | { |
| 973 | unsigned long i; |
| 974 | |
| 975 | for (i = 0; i < max_scan; i++) { |
| 976 | if (!radix_tree_lookup(root, index)) |
| 977 | break; |
| 978 | index++; |
| 979 | if (index == 0) |
| 980 | break; |
| 981 | } |
| 982 | |
| 983 | return index; |
| 984 | } |
| 985 | EXPORT_SYMBOL(radix_tree_next_hole); |
| 986 | |
Wu Fengguang | dc56612 | 2009-06-16 15:31:32 -0700 | [diff] [blame] | 987 | /** |
| 988 | * radix_tree_prev_hole - find the prev hole (not-present entry) |
| 989 | * @root: tree root |
| 990 | * @index: index key |
| 991 | * @max_scan: maximum range to search |
| 992 | * |
| 993 | * Search backwards in the range [max(index-max_scan+1, 0), index] |
| 994 | * for the first hole. |
| 995 | * |
| 996 | * Returns: the index of the hole if found, otherwise returns an index |
| 997 | * outside of the set specified (in which case 'index - return >= max_scan' |
Cesar Eduardo Barros | edcd1d8 | 2010-05-26 14:44:27 -0700 | [diff] [blame] | 998 | * will be true). In rare cases of wrap-around, ULONG_MAX will be returned. |
Wu Fengguang | dc56612 | 2009-06-16 15:31:32 -0700 | [diff] [blame] | 999 | * |
| 1000 | * radix_tree_next_hole may be called under rcu_read_lock. However, like |
| 1001 | * radix_tree_gang_lookup, this will not atomically search a snapshot of |
| 1002 | * the tree at a single point in time. For example, if a hole is created |
| 1003 | * at index 10, then subsequently a hole is created at index 5, |
| 1004 | * radix_tree_prev_hole covering both indexes may return 5 if called under |
| 1005 | * rcu_read_lock. |
| 1006 | */ |
| 1007 | unsigned long radix_tree_prev_hole(struct radix_tree_root *root, |
| 1008 | unsigned long index, unsigned long max_scan) |
| 1009 | { |
| 1010 | unsigned long i; |
| 1011 | |
| 1012 | for (i = 0; i < max_scan; i++) { |
| 1013 | if (!radix_tree_lookup(root, index)) |
| 1014 | break; |
| 1015 | index--; |
Cesar Eduardo Barros | edcd1d8 | 2010-05-26 14:44:27 -0700 | [diff] [blame] | 1016 | if (index == ULONG_MAX) |
Wu Fengguang | dc56612 | 2009-06-16 15:31:32 -0700 | [diff] [blame] | 1017 | break; |
| 1018 | } |
| 1019 | |
| 1020 | return index; |
| 1021 | } |
| 1022 | EXPORT_SYMBOL(radix_tree_prev_hole); |
| 1023 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | /** |
| 1025 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree |
| 1026 | * @root: radix tree root |
| 1027 | * @results: where the results of the lookup are placed |
| 1028 | * @first_index: start the lookup from this key |
| 1029 | * @max_items: place up to this many items at *results |
| 1030 | * |
| 1031 | * Performs an index-ascending scan of the tree for present items. Places |
| 1032 | * them at *@results and returns the number of items which were placed at |
| 1033 | * *@results. |
| 1034 | * |
| 1035 | * The implementation is naive. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1036 | * |
| 1037 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under |
| 1038 | * rcu_read_lock. In this case, rather than the returned results being |
| 1039 | * an atomic snapshot of the tree at a single point in time, the semantics |
| 1040 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups |
| 1041 | * have been issued in individual locks, and results stored in 'results'. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | */ |
| 1043 | unsigned int |
| 1044 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, |
| 1045 | unsigned long first_index, unsigned int max_items) |
| 1046 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1047 | struct radix_tree_iter iter; |
| 1048 | void **slot; |
| 1049 | unsigned int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1050 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1051 | if (unlikely(!max_items)) |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1052 | return 0; |
| 1053 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1054 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
| 1055 | results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); |
| 1056 | if (!results[ret]) |
| 1057 | continue; |
| 1058 | if (++ret == max_items) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1060 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1061 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | return ret; |
| 1063 | } |
| 1064 | EXPORT_SYMBOL(radix_tree_gang_lookup); |
| 1065 | |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1066 | /** |
| 1067 | * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree |
| 1068 | * @root: radix tree root |
| 1069 | * @results: where the results of the lookup are placed |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1070 | * @indices: where their indices should be placed (but usually NULL) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1071 | * @first_index: start the lookup from this key |
| 1072 | * @max_items: place up to this many items at *results |
| 1073 | * |
| 1074 | * Performs an index-ascending scan of the tree for present items. Places |
| 1075 | * their slots at *@results and returns the number of items which were |
| 1076 | * placed at *@results. |
| 1077 | * |
| 1078 | * The implementation is naive. |
| 1079 | * |
| 1080 | * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must |
| 1081 | * be dereferenced with radix_tree_deref_slot, and if using only RCU |
| 1082 | * protection, radix_tree_deref_slot may fail requiring a retry. |
| 1083 | */ |
| 1084 | unsigned int |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1085 | radix_tree_gang_lookup_slot(struct radix_tree_root *root, |
| 1086 | void ***results, unsigned long *indices, |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1087 | unsigned long first_index, unsigned int max_items) |
| 1088 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1089 | struct radix_tree_iter iter; |
| 1090 | void **slot; |
| 1091 | unsigned int ret = 0; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1092 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1093 | if (unlikely(!max_items)) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1094 | return 0; |
| 1095 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1096 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
| 1097 | results[ret] = slot; |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1098 | if (indices) |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1099 | indices[ret] = iter.index; |
| 1100 | if (++ret == max_items) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1101 | break; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1102 | } |
| 1103 | |
| 1104 | return ret; |
| 1105 | } |
| 1106 | EXPORT_SYMBOL(radix_tree_gang_lookup_slot); |
| 1107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | /** |
| 1109 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree |
| 1110 | * based on a tag |
| 1111 | * @root: radix tree root |
| 1112 | * @results: where the results of the lookup are placed |
| 1113 | * @first_index: start the lookup from this key |
| 1114 | * @max_items: place up to this many items at *results |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1115 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | * |
| 1117 | * Performs an index-ascending scan of the tree for present items which |
| 1118 | * have the tag indexed by @tag set. Places the items at *@results and |
| 1119 | * returns the number of items which were placed at *@results. |
| 1120 | */ |
| 1121 | unsigned int |
| 1122 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1123 | unsigned long first_index, unsigned int max_items, |
| 1124 | unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1126 | struct radix_tree_iter iter; |
| 1127 | void **slot; |
| 1128 | unsigned int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1130 | if (unlikely(!max_items)) |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1131 | return 0; |
| 1132 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1133 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
| 1134 | results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); |
| 1135 | if (!results[ret]) |
| 1136 | continue; |
| 1137 | if (++ret == max_items) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | return ret; |
| 1142 | } |
| 1143 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); |
| 1144 | |
| 1145 | /** |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1146 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a |
| 1147 | * radix tree based on a tag |
| 1148 | * @root: radix tree root |
| 1149 | * @results: where the results of the lookup are placed |
| 1150 | * @first_index: start the lookup from this key |
| 1151 | * @max_items: place up to this many items at *results |
| 1152 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
| 1153 | * |
| 1154 | * Performs an index-ascending scan of the tree for present items which |
| 1155 | * have the tag indexed by @tag set. Places the slots at *@results and |
| 1156 | * returns the number of slots which were placed at *@results. |
| 1157 | */ |
| 1158 | unsigned int |
| 1159 | radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, |
| 1160 | unsigned long first_index, unsigned int max_items, |
| 1161 | unsigned int tag) |
| 1162 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1163 | struct radix_tree_iter iter; |
| 1164 | void **slot; |
| 1165 | unsigned int ret = 0; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1166 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1167 | if (unlikely(!max_items)) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1168 | return 0; |
| 1169 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1170 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
| 1171 | results[ret] = slot; |
| 1172 | if (++ret == max_items) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1173 | break; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1174 | } |
| 1175 | |
| 1176 | return ret; |
| 1177 | } |
| 1178 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); |
| 1179 | |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1180 | #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP) |
| 1181 | #include <linux/sched.h> /* for cond_resched() */ |
| 1182 | |
| 1183 | /* |
| 1184 | * This linear search is at present only useful to shmem_unuse_inode(). |
| 1185 | */ |
| 1186 | static unsigned long __locate(struct radix_tree_node *slot, void *item, |
| 1187 | unsigned long index, unsigned long *found_index) |
| 1188 | { |
| 1189 | unsigned int shift, height; |
| 1190 | unsigned long i; |
| 1191 | |
| 1192 | height = slot->height; |
| 1193 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
| 1194 | |
| 1195 | for ( ; height > 1; height--) { |
| 1196 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 1197 | for (;;) { |
| 1198 | if (slot->slots[i] != NULL) |
| 1199 | break; |
| 1200 | index &= ~((1UL << shift) - 1); |
| 1201 | index += 1UL << shift; |
| 1202 | if (index == 0) |
| 1203 | goto out; /* 32-bit wraparound */ |
| 1204 | i++; |
| 1205 | if (i == RADIX_TREE_MAP_SIZE) |
| 1206 | goto out; |
| 1207 | } |
| 1208 | |
| 1209 | shift -= RADIX_TREE_MAP_SHIFT; |
| 1210 | slot = rcu_dereference_raw(slot->slots[i]); |
| 1211 | if (slot == NULL) |
| 1212 | goto out; |
| 1213 | } |
| 1214 | |
| 1215 | /* Bottom level: check items */ |
| 1216 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { |
| 1217 | if (slot->slots[i] == item) { |
| 1218 | *found_index = index + i; |
| 1219 | index = 0; |
| 1220 | goto out; |
| 1221 | } |
| 1222 | } |
| 1223 | index += RADIX_TREE_MAP_SIZE; |
| 1224 | out: |
| 1225 | return index; |
| 1226 | } |
| 1227 | |
| 1228 | /** |
| 1229 | * radix_tree_locate_item - search through radix tree for item |
| 1230 | * @root: radix tree root |
| 1231 | * @item: item to be found |
| 1232 | * |
| 1233 | * Returns index where item was found, or -1 if not found. |
| 1234 | * Caller must hold no lock (since this time-consuming function needs |
| 1235 | * to be preemptible), and must check afterwards if item is still there. |
| 1236 | */ |
| 1237 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) |
| 1238 | { |
| 1239 | struct radix_tree_node *node; |
| 1240 | unsigned long max_index; |
| 1241 | unsigned long cur_index = 0; |
| 1242 | unsigned long found_index = -1; |
| 1243 | |
| 1244 | do { |
| 1245 | rcu_read_lock(); |
| 1246 | node = rcu_dereference_raw(root->rnode); |
| 1247 | if (!radix_tree_is_indirect_ptr(node)) { |
| 1248 | rcu_read_unlock(); |
| 1249 | if (node == item) |
| 1250 | found_index = 0; |
| 1251 | break; |
| 1252 | } |
| 1253 | |
| 1254 | node = indirect_to_ptr(node); |
| 1255 | max_index = radix_tree_maxindex(node->height); |
| 1256 | if (cur_index > max_index) |
| 1257 | break; |
| 1258 | |
| 1259 | cur_index = __locate(node, item, cur_index, &found_index); |
| 1260 | rcu_read_unlock(); |
| 1261 | cond_resched(); |
| 1262 | } while (cur_index != 0 && cur_index <= max_index); |
| 1263 | |
| 1264 | return found_index; |
| 1265 | } |
| 1266 | #else |
| 1267 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) |
| 1268 | { |
| 1269 | return -1; |
| 1270 | } |
| 1271 | #endif /* CONFIG_SHMEM && CONFIG_SWAP */ |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1272 | |
| 1273 | /** |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1274 | * radix_tree_shrink - shrink height of a radix tree to minimal |
| 1275 | * @root radix tree root |
| 1276 | */ |
| 1277 | static inline void radix_tree_shrink(struct radix_tree_root *root) |
| 1278 | { |
| 1279 | /* try to shrink tree height */ |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1280 | while (root->height > 0) { |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1281 | struct radix_tree_node *to_free = root->rnode; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1282 | struct radix_tree_node *slot; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1283 | |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1284 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1285 | to_free = indirect_to_ptr(to_free); |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1286 | |
| 1287 | /* |
| 1288 | * The candidate node has more than one child, or its child |
| 1289 | * is not at the leftmost slot, we cannot shrink. |
| 1290 | */ |
| 1291 | if (to_free->count != 1) |
| 1292 | break; |
| 1293 | if (!to_free->slots[0]) |
| 1294 | break; |
| 1295 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1296 | /* |
| 1297 | * We don't need rcu_assign_pointer(), since we are simply |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1298 | * moving the node from one part of the tree to another: if it |
| 1299 | * was safe to dereference the old pointer to it |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1300 | * (to_free->slots[0]), it will be safe to dereference the new |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1301 | * one (root->rnode) as far as dependent read barriers go. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1302 | */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1303 | slot = to_free->slots[0]; |
| 1304 | if (root->height > 1) { |
| 1305 | slot->parent = NULL; |
| 1306 | slot = ptr_to_indirect(slot); |
| 1307 | } |
| 1308 | root->rnode = slot; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1309 | root->height--; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1310 | |
| 1311 | /* |
| 1312 | * We have a dilemma here. The node's slot[0] must not be |
| 1313 | * NULLed in case there are concurrent lookups expecting to |
| 1314 | * find the item. However if this was a bottom-level node, |
| 1315 | * then it may be subject to the slot pointer being visible |
| 1316 | * to callers dereferencing it. If item corresponding to |
| 1317 | * slot[0] is subsequently deleted, these callers would expect |
| 1318 | * their slot to become empty sooner or later. |
| 1319 | * |
| 1320 | * For example, lockless pagecache will look up a slot, deref |
| 1321 | * the page pointer, and if the page is 0 refcount it means it |
| 1322 | * was concurrently deleted from pagecache so try the deref |
| 1323 | * again. Fortunately there is already a requirement for logic |
| 1324 | * to retry the entire slot lookup -- the indirect pointer |
| 1325 | * problem (replacing direct root node with an indirect pointer |
| 1326 | * also results in a stale slot). So tag the slot as indirect |
| 1327 | * to force callers to retry. |
| 1328 | */ |
| 1329 | if (root->height == 0) |
| 1330 | *((unsigned long *)&to_free->slots[0]) |= |
| 1331 | RADIX_TREE_INDIRECT_PTR; |
| 1332 | |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1333 | radix_tree_node_free(to_free); |
| 1334 | } |
| 1335 | } |
| 1336 | |
| 1337 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1338 | * radix_tree_delete - delete an item from a radix tree |
| 1339 | * @root: radix tree root |
| 1340 | * @index: index key |
| 1341 | * |
| 1342 | * Remove the item at @index from the radix tree rooted at @root. |
| 1343 | * |
| 1344 | * Returns the address of the deleted item, or NULL if it was not present. |
| 1345 | */ |
| 1346 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) |
| 1347 | { |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1348 | struct radix_tree_node *node = NULL; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1349 | struct radix_tree_node *slot = NULL; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1350 | struct radix_tree_node *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1351 | unsigned int height, shift; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1352 | int tag; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1353 | int uninitialized_var(offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1354 | |
| 1355 | height = root->height; |
| 1356 | if (index > radix_tree_maxindex(height)) |
| 1357 | goto out; |
| 1358 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1359 | slot = root->rnode; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1360 | if (height == 0) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1361 | root_tag_clear_all(root); |
| 1362 | root->rnode = NULL; |
| 1363 | goto out; |
| 1364 | } |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1365 | slot = indirect_to_ptr(slot); |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1366 | shift = height * RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1367 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1368 | do { |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1369 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1370 | goto out; |
| 1371 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1372 | shift -= RADIX_TREE_MAP_SHIFT; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1373 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 1374 | node = slot; |
| 1375 | slot = slot->slots[offset]; |
| 1376 | } while (shift); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1377 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1378 | if (slot == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1379 | goto out; |
| 1380 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1381 | /* |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1382 | * Clear all tags associated with the item to be deleted. |
| 1383 | * This way of doing it would be inefficient, but seldom is any set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1384 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1385 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1386 | if (tag_get(node, tag, offset)) |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1387 | radix_tree_tag_clear(root, index, tag); |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1388 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1389 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1390 | to_free = NULL; |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1391 | /* Now free the nodes we do not need anymore */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1392 | while (node) { |
| 1393 | node->slots[offset] = NULL; |
| 1394 | node->count--; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1395 | /* |
| 1396 | * Queue the node for deferred freeing after the |
| 1397 | * last reference to it disappears (set NULL, above). |
| 1398 | */ |
| 1399 | if (to_free) |
| 1400 | radix_tree_node_free(to_free); |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1401 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1402 | if (node->count) { |
| 1403 | if (node == indirect_to_ptr(root->rnode)) |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1404 | radix_tree_shrink(root); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1405 | goto out; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1406 | } |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1407 | |
| 1408 | /* Node with zero slots in use so free it */ |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1409 | to_free = node; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1410 | |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1411 | index >>= RADIX_TREE_MAP_SHIFT; |
| 1412 | offset = index & RADIX_TREE_MAP_MASK; |
| 1413 | node = node->parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | } |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 1415 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1416 | root_tag_clear_all(root); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1417 | root->height = 0; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1418 | root->rnode = NULL; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1419 | if (to_free) |
| 1420 | radix_tree_node_free(to_free); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1421 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1422 | out: |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1423 | return slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1424 | } |
| 1425 | EXPORT_SYMBOL(radix_tree_delete); |
| 1426 | |
| 1427 | /** |
| 1428 | * radix_tree_tagged - test whether any items in the tree are tagged |
| 1429 | * @root: radix tree root |
| 1430 | * @tag: tag to test |
| 1431 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1432 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1433 | { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1434 | return root_tag_get(root, tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | } |
| 1436 | EXPORT_SYMBOL(radix_tree_tagged); |
| 1437 | |
| 1438 | static void |
Alexey Dobriyan | 51cc506 | 2008-07-25 19:45:34 -0700 | [diff] [blame] | 1439 | radix_tree_node_ctor(void *node) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1440 | { |
| 1441 | memset(node, 0, sizeof(struct radix_tree_node)); |
| 1442 | } |
| 1443 | |
| 1444 | static __init unsigned long __maxindex(unsigned int height) |
| 1445 | { |
Peter Lund | 430d275 | 2007-10-16 23:29:35 -0700 | [diff] [blame] | 1446 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
| 1447 | int shift = RADIX_TREE_INDEX_BITS - width; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1448 | |
Peter Lund | 430d275 | 2007-10-16 23:29:35 -0700 | [diff] [blame] | 1449 | if (shift < 0) |
| 1450 | return ~0UL; |
| 1451 | if (shift >= BITS_PER_LONG) |
| 1452 | return 0UL; |
| 1453 | return ~0UL >> shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1454 | } |
| 1455 | |
| 1456 | static __init void radix_tree_init_maxindex(void) |
| 1457 | { |
| 1458 | unsigned int i; |
| 1459 | |
| 1460 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) |
| 1461 | height_to_maxindex[i] = __maxindex(i); |
| 1462 | } |
| 1463 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1464 | static int radix_tree_callback(struct notifier_block *nfb, |
| 1465 | unsigned long action, |
| 1466 | void *hcpu) |
| 1467 | { |
| 1468 | int cpu = (long)hcpu; |
| 1469 | struct radix_tree_preload *rtp; |
| 1470 | |
| 1471 | /* Free per-cpu pool of perloaded nodes */ |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 1472 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1473 | rtp = &per_cpu(radix_tree_preloads, cpu); |
| 1474 | while (rtp->nr) { |
| 1475 | kmem_cache_free(radix_tree_node_cachep, |
| 1476 | rtp->nodes[rtp->nr-1]); |
| 1477 | rtp->nodes[rtp->nr-1] = NULL; |
| 1478 | rtp->nr--; |
| 1479 | } |
| 1480 | } |
| 1481 | return NOTIFY_OK; |
| 1482 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | |
| 1484 | void __init radix_tree_init(void) |
| 1485 | { |
| 1486 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
| 1487 | sizeof(struct radix_tree_node), 0, |
Christoph Lameter | 488514d | 2008-04-28 02:12:05 -0700 | [diff] [blame] | 1488 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
| 1489 | radix_tree_node_ctor); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1490 | radix_tree_init_maxindex(); |
| 1491 | hotcpu_notifier(radix_tree_callback, 0); |
| 1492 | } |