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 |
Matthew Wilcox | 6b053b8 | 2016-05-20 17:02:58 -0700 | [diff] [blame] | 7 | * Copyright (C) 2016 Intel, Matthew Wilcox |
| 8 | * Copyright (C) 2016 Intel, Ross Zwisler |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * |
| 10 | * This program is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU General Public License as |
| 12 | * published by the Free Software Foundation; either version 2, or (at |
| 13 | * your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, but |
| 16 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 18 | * General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, write to the Free Software |
| 22 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 23 | */ |
| 24 | |
| 25 | #include <linux/errno.h> |
| 26 | #include <linux/init.h> |
| 27 | #include <linux/kernel.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 28 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/radix-tree.h> |
| 30 | #include <linux/percpu.h> |
| 31 | #include <linux/slab.h> |
Catalin Marinas | ce80b06 | 2014-06-06 14:38:18 -0700 | [diff] [blame] | 32 | #include <linux/kmemleak.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #include <linux/notifier.h> |
| 34 | #include <linux/cpu.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/string.h> |
| 36 | #include <linux/bitops.h> |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 37 | #include <linux/rcupdate.h> |
Frederic Weisbecker | 92cf211 | 2015-05-12 16:41:46 +0200 | [diff] [blame] | 38 | #include <linux/preempt.h> /* in_interrupt() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | |
| 40 | |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 41 | /* Number of nodes in fully populated tree of given height */ |
| 42 | static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly; |
| 43 | |
Jeff Moyer | 26fb158 | 2007-10-16 01:24:49 -0700 | [diff] [blame] | 44 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | * Radix tree node cache. |
| 46 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 47 | static struct kmem_cache *radix_tree_node_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
| 49 | /* |
Nick Piggin | 5536805 | 2012-05-29 15:07:34 -0700 | [diff] [blame] | 50 | * The radix tree is variable-height, so an insert operation not only has |
| 51 | * to build the branch to its corresponding item, it also has to build the |
| 52 | * branch to existing items if the size has to be increased (by |
| 53 | * radix_tree_extend). |
| 54 | * |
| 55 | * The worst case is a zero height tree with just a single item at index 0, |
| 56 | * and then inserting an item at index ULONG_MAX. This requires 2 new branches |
| 57 | * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. |
| 58 | * Hence: |
| 59 | */ |
| 60 | #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) |
| 61 | |
| 62 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | * Per-cpu pool of preloaded nodes |
| 64 | */ |
| 65 | struct radix_tree_preload { |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 66 | unsigned nr; |
Kirill A. Shutemov | 9d2a8da | 2015-06-25 15:02:19 -0700 | [diff] [blame] | 67 | /* nodes->private_data points to next preallocated node */ |
| 68 | struct radix_tree_node *nodes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | }; |
Harvey Harrison | 8cef7d5 | 2009-01-06 14:40:50 -0800 | [diff] [blame] | 70 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
Matthew Wilcox | a4db4dc | 2016-05-20 17:03:24 -0700 | [diff] [blame] | 72 | static inline void *node_to_entry(void *ptr) |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 73 | { |
Matthew Wilcox | 30ff46cc | 2016-05-20 17:03:22 -0700 | [diff] [blame] | 74 | return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE); |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 75 | } |
| 76 | |
Matthew Wilcox | a4db4dc | 2016-05-20 17:03:24 -0700 | [diff] [blame] | 77 | #define RADIX_TREE_RETRY node_to_entry(NULL) |
Matthew Wilcox | afe0e39 | 2016-05-20 17:02:17 -0700 | [diff] [blame] | 78 | |
Matthew Wilcox | db050f2 | 2016-05-20 17:01:57 -0700 | [diff] [blame] | 79 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| 80 | /* Sibling slots point directly to another slot in the same node */ |
| 81 | static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) |
| 82 | { |
| 83 | void **ptr = node; |
| 84 | return (parent->slots <= ptr) && |
| 85 | (ptr < parent->slots + RADIX_TREE_MAP_SIZE); |
| 86 | } |
| 87 | #else |
| 88 | static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) |
| 89 | { |
| 90 | return false; |
| 91 | } |
| 92 | #endif |
| 93 | |
| 94 | static inline unsigned long get_slot_offset(struct radix_tree_node *parent, |
| 95 | void **slot) |
| 96 | { |
| 97 | return slot - parent->slots; |
| 98 | } |
| 99 | |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 100 | static unsigned int radix_tree_descend(struct radix_tree_node *parent, |
| 101 | struct radix_tree_node **nodep, unsigned long index) |
Matthew Wilcox | db050f2 | 2016-05-20 17:01:57 -0700 | [diff] [blame] | 102 | { |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 103 | unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; |
Matthew Wilcox | db050f2 | 2016-05-20 17:01:57 -0700 | [diff] [blame] | 104 | void **entry = rcu_dereference_raw(parent->slots[offset]); |
| 105 | |
| 106 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 107 | if (radix_tree_is_internal_node(entry)) { |
Matthew Wilcox | db050f2 | 2016-05-20 17:01:57 -0700 | [diff] [blame] | 108 | unsigned long siboff = get_slot_offset(parent, entry); |
| 109 | if (siboff < RADIX_TREE_MAP_SIZE) { |
| 110 | offset = siboff; |
| 111 | entry = rcu_dereference_raw(parent->slots[offset]); |
| 112 | } |
| 113 | } |
| 114 | #endif |
| 115 | |
| 116 | *nodep = (void *)entry; |
| 117 | return offset; |
| 118 | } |
| 119 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 120 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
| 121 | { |
| 122 | return root->gfp_mask & __GFP_BITS_MASK; |
| 123 | } |
| 124 | |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 125 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
| 126 | int offset) |
| 127 | { |
| 128 | __set_bit(offset, node->tags[tag]); |
| 129 | } |
| 130 | |
| 131 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
| 132 | int offset) |
| 133 | { |
| 134 | __clear_bit(offset, node->tags[tag]); |
| 135 | } |
| 136 | |
| 137 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
| 138 | int offset) |
| 139 | { |
| 140 | return test_bit(offset, node->tags[tag]); |
| 141 | } |
| 142 | |
| 143 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
| 144 | { |
| 145 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
| 146 | } |
| 147 | |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 148 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag) |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 149 | { |
| 150 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
| 151 | } |
| 152 | |
| 153 | static inline void root_tag_clear_all(struct radix_tree_root *root) |
| 154 | { |
| 155 | root->gfp_mask &= __GFP_BITS_MASK; |
| 156 | } |
| 157 | |
| 158 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) |
| 159 | { |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 160 | return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 161 | } |
| 162 | |
Matthew Wilcox | 7b60e9a | 2016-05-20 17:02:23 -0700 | [diff] [blame] | 163 | static inline unsigned root_tags_get(struct radix_tree_root *root) |
| 164 | { |
| 165 | return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; |
| 166 | } |
| 167 | |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 168 | /* |
| 169 | * Returns 1 if any slot in the node has this tag set. |
| 170 | * Otherwise returns 0. |
| 171 | */ |
| 172 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
| 173 | { |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 174 | unsigned idx; |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 175 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
| 176 | if (node->tags[tag][idx]) |
| 177 | return 1; |
| 178 | } |
| 179 | return 0; |
| 180 | } |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 181 | |
| 182 | /** |
| 183 | * radix_tree_find_next_bit - find the next set bit in a memory region |
| 184 | * |
| 185 | * @addr: The address to base the search on |
| 186 | * @size: The bitmap size in bits |
| 187 | * @offset: The bitnumber to start searching at |
| 188 | * |
| 189 | * Unrollable variant of find_next_bit() for constant size arrays. |
| 190 | * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. |
| 191 | * Returns next bit offset, or size if nothing found. |
| 192 | */ |
| 193 | static __always_inline unsigned long |
| 194 | radix_tree_find_next_bit(const unsigned long *addr, |
| 195 | unsigned long size, unsigned long offset) |
| 196 | { |
| 197 | if (!__builtin_constant_p(size)) |
| 198 | return find_next_bit(addr, size, offset); |
| 199 | |
| 200 | if (offset < size) { |
| 201 | unsigned long tmp; |
| 202 | |
| 203 | addr += offset / BITS_PER_LONG; |
| 204 | tmp = *addr >> (offset % BITS_PER_LONG); |
| 205 | if (tmp) |
| 206 | return __ffs(tmp) + offset; |
| 207 | offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); |
| 208 | while (offset < size) { |
| 209 | tmp = *++addr; |
| 210 | if (tmp) |
| 211 | return __ffs(tmp) + offset; |
| 212 | offset += BITS_PER_LONG; |
| 213 | } |
| 214 | } |
| 215 | return size; |
| 216 | } |
| 217 | |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 218 | #ifndef __KERNEL__ |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 219 | static void dump_node(struct radix_tree_node *node, unsigned long index) |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 220 | { |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 221 | unsigned long i; |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 222 | |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 223 | pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d parent %p\n", |
Matthew Wilcox | 0c7fa0a | 2016-05-20 17:03:07 -0700 | [diff] [blame] | 224 | node, node->offset, |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 225 | node->tags[0][0], node->tags[1][0], node->tags[2][0], |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 226 | node->shift, node->count, node->parent); |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 227 | |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 228 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 229 | unsigned long first = index | (i << node->shift); |
| 230 | unsigned long last = first | ((1UL << node->shift) - 1); |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 231 | void *entry = node->slots[i]; |
| 232 | if (!entry) |
| 233 | continue; |
| 234 | if (is_sibling_entry(node, entry)) { |
| 235 | pr_debug("radix sblng %p offset %ld val %p indices %ld-%ld\n", |
| 236 | entry, i, |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 237 | *(void **)entry_to_node(entry), |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 238 | first, last); |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 239 | } else if (!radix_tree_is_internal_node(entry)) { |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 240 | pr_debug("radix entry %p offset %ld indices %ld-%ld\n", |
| 241 | entry, i, first, last); |
| 242 | } else { |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 243 | dump_node(entry_to_node(entry), first); |
Ross Zwisler | 0796c58 | 2016-05-20 17:02:55 -0700 | [diff] [blame] | 244 | } |
| 245 | } |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 246 | } |
| 247 | |
| 248 | /* For debug */ |
| 249 | static void radix_tree_dump(struct radix_tree_root *root) |
| 250 | { |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 251 | pr_debug("radix root: %p rnode %p tags %x\n", |
| 252 | root, root->rnode, |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 253 | root->gfp_mask >> __GFP_BITS_SHIFT); |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 254 | if (!radix_tree_is_internal_node(root->rnode)) |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 255 | return; |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 256 | dump_node(entry_to_node(root->rnode), 0); |
Matthew Wilcox | 7cf19af | 2016-03-17 14:21:57 -0700 | [diff] [blame] | 257 | } |
| 258 | #endif |
| 259 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | /* |
| 261 | * This assumes that the caller has performed appropriate preallocation, and |
| 262 | * that the caller has pinned this thread of control to the current CPU. |
| 263 | */ |
| 264 | static struct radix_tree_node * |
| 265 | radix_tree_node_alloc(struct radix_tree_root *root) |
| 266 | { |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 267 | struct radix_tree_node *ret = NULL; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 268 | gfp_t gfp_mask = root_gfp_mask(root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 270 | /* |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 271 | * Preload code isn't irq safe and it doesn't make sense to use |
| 272 | * preloading during an interrupt anyway as all the allocations have |
| 273 | * to be atomic. So just do normal allocation when in interrupt. |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 274 | */ |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 275 | if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | struct radix_tree_preload *rtp; |
| 277 | |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 278 | /* |
Vladimir Davydov | 58e698a | 2016-03-17 14:18:36 -0700 | [diff] [blame] | 279 | * Even if the caller has preloaded, try to allocate from the |
| 280 | * cache first for the new node to get accounted. |
| 281 | */ |
| 282 | ret = kmem_cache_alloc(radix_tree_node_cachep, |
| 283 | gfp_mask | __GFP_ACCOUNT | __GFP_NOWARN); |
| 284 | if (ret) |
| 285 | goto out; |
| 286 | |
| 287 | /* |
Nick Piggin | e2848a0 | 2008-02-04 22:29:10 -0800 | [diff] [blame] | 288 | * Provided the caller has preloaded here, we will always |
| 289 | * succeed in getting a node here (and never reach |
| 290 | * kmem_cache_alloc) |
| 291 | */ |
Christoph Lameter | 7c8e018 | 2014-06-04 16:07:56 -0700 | [diff] [blame] | 292 | rtp = this_cpu_ptr(&radix_tree_preloads); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | if (rtp->nr) { |
Kirill A. Shutemov | 9d2a8da | 2015-06-25 15:02:19 -0700 | [diff] [blame] | 294 | ret = rtp->nodes; |
| 295 | rtp->nodes = ret->private_data; |
| 296 | ret->private_data = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | rtp->nr--; |
| 298 | } |
Catalin Marinas | ce80b06 | 2014-06-06 14:38:18 -0700 | [diff] [blame] | 299 | /* |
| 300 | * Update the allocation stack trace as this is more useful |
| 301 | * for debugging. |
| 302 | */ |
| 303 | kmemleak_update_trace(ret); |
Vladimir Davydov | 58e698a | 2016-03-17 14:18:36 -0700 | [diff] [blame] | 304 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | } |
Vladimir Davydov | 58e698a | 2016-03-17 14:18:36 -0700 | [diff] [blame] | 306 | ret = kmem_cache_alloc(radix_tree_node_cachep, |
| 307 | gfp_mask | __GFP_ACCOUNT); |
| 308 | out: |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 309 | BUG_ON(radix_tree_is_internal_node(ret)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | return ret; |
| 311 | } |
| 312 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 313 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
| 314 | { |
| 315 | struct radix_tree_node *node = |
| 316 | container_of(head, struct radix_tree_node, rcu_head); |
Dave Chinner | b6dd086 | 2010-08-23 10:33:19 +1000 | [diff] [blame] | 317 | int i; |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 318 | |
| 319 | /* |
| 320 | * must only free zeroed nodes into the slab. radix_tree_shrink |
| 321 | * can leave us with a non-NULL entry in the first slot, so clear |
| 322 | * that here to make sure. |
| 323 | */ |
Dave Chinner | b6dd086 | 2010-08-23 10:33:19 +1000 | [diff] [blame] | 324 | for (i = 0; i < RADIX_TREE_MAX_TAGS; i++) |
| 325 | tag_clear(node, i, 0); |
| 326 | |
Nick Piggin | 643b52b | 2008-06-12 15:21:52 -0700 | [diff] [blame] | 327 | node->slots[0] = NULL; |
| 328 | node->count = 0; |
| 329 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 330 | kmem_cache_free(radix_tree_node_cachep, node); |
| 331 | } |
| 332 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | static inline void |
| 334 | radix_tree_node_free(struct radix_tree_node *node) |
| 335 | { |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 336 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| 341 | * ensure that the addition of a single element in the tree cannot fail. On |
| 342 | * success, return zero, with preemption disabled. On error, return -ENOMEM |
| 343 | * with preemption not disabled. |
David Howells | b34df79 | 2009-11-19 18:11:14 +0000 | [diff] [blame] | 344 | * |
| 345 | * To make use of this facility, the radix tree must be initialised without |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 346 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | */ |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 348 | static int __radix_tree_preload(gfp_t gfp_mask, int nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | { |
| 350 | struct radix_tree_preload *rtp; |
| 351 | struct radix_tree_node *node; |
| 352 | int ret = -ENOMEM; |
| 353 | |
| 354 | preempt_disable(); |
Christoph Lameter | 7c8e018 | 2014-06-04 16:07:56 -0700 | [diff] [blame] | 355 | rtp = this_cpu_ptr(&radix_tree_preloads); |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 356 | while (rtp->nr < nr) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | preempt_enable(); |
Christoph Lameter | 488514d | 2008-04-28 02:12:05 -0700 | [diff] [blame] | 358 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | if (node == NULL) |
| 360 | goto out; |
| 361 | preempt_disable(); |
Christoph Lameter | 7c8e018 | 2014-06-04 16:07:56 -0700 | [diff] [blame] | 362 | rtp = this_cpu_ptr(&radix_tree_preloads); |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 363 | if (rtp->nr < nr) { |
Kirill A. Shutemov | 9d2a8da | 2015-06-25 15:02:19 -0700 | [diff] [blame] | 364 | node->private_data = rtp->nodes; |
| 365 | rtp->nodes = node; |
| 366 | rtp->nr++; |
| 367 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | kmem_cache_free(radix_tree_node_cachep, node); |
Kirill A. Shutemov | 9d2a8da | 2015-06-25 15:02:19 -0700 | [diff] [blame] | 369 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | } |
| 371 | ret = 0; |
| 372 | out: |
| 373 | return ret; |
| 374 | } |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 375 | |
| 376 | /* |
| 377 | * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| 378 | * ensure that the addition of a single element in the tree cannot fail. On |
| 379 | * success, return zero, with preemption disabled. On error, return -ENOMEM |
| 380 | * with preemption not disabled. |
| 381 | * |
| 382 | * To make use of this facility, the radix tree must be initialised without |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 383 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 384 | */ |
| 385 | int radix_tree_preload(gfp_t gfp_mask) |
| 386 | { |
| 387 | /* Warn on non-sensical use... */ |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 388 | WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 389 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 390 | } |
David Chinner | d7f0923 | 2007-07-14 16:05:04 +1000 | [diff] [blame] | 391 | EXPORT_SYMBOL(radix_tree_preload); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | |
Nick Piggin | 6e954b9 | 2006-01-08 01:01:40 -0800 | [diff] [blame] | 393 | /* |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 394 | * The same as above function, except we don't guarantee preloading happens. |
| 395 | * We do it, if we decide it helps. On success, return zero with preemption |
| 396 | * disabled. On error, return -ENOMEM with preemption not disabled. |
| 397 | */ |
| 398 | int radix_tree_maybe_preload(gfp_t gfp_mask) |
| 399 | { |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 400 | if (gfpflags_allow_blocking(gfp_mask)) |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 401 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
Jan Kara | 5e4c0d97 | 2013-09-11 14:26:05 -0700 | [diff] [blame] | 402 | /* Preloading doesn't help anything with this gfp mask, skip it */ |
| 403 | preempt_disable(); |
| 404 | return 0; |
| 405 | } |
| 406 | EXPORT_SYMBOL(radix_tree_maybe_preload); |
| 407 | |
| 408 | /* |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 409 | * The same as function above, but preload number of nodes required to insert |
| 410 | * (1 << order) continuous naturally-aligned elements. |
| 411 | */ |
| 412 | int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order) |
| 413 | { |
| 414 | unsigned long nr_subtrees; |
| 415 | int nr_nodes, subtree_height; |
| 416 | |
| 417 | /* Preloading doesn't help anything with this gfp mask, skip it */ |
| 418 | if (!gfpflags_allow_blocking(gfp_mask)) { |
| 419 | preempt_disable(); |
| 420 | return 0; |
| 421 | } |
| 422 | |
| 423 | /* |
| 424 | * Calculate number and height of fully populated subtrees it takes to |
| 425 | * store (1 << order) elements. |
| 426 | */ |
| 427 | nr_subtrees = 1 << order; |
| 428 | for (subtree_height = 0; nr_subtrees > RADIX_TREE_MAP_SIZE; |
| 429 | subtree_height++) |
| 430 | nr_subtrees >>= RADIX_TREE_MAP_SHIFT; |
| 431 | |
| 432 | /* |
| 433 | * The worst case is zero height tree with a single item at index 0 and |
| 434 | * then inserting items starting at ULONG_MAX - (1 << order). |
| 435 | * |
| 436 | * This requires RADIX_TREE_MAX_PATH nodes to build branch from root to |
| 437 | * 0-index item. |
| 438 | */ |
| 439 | nr_nodes = RADIX_TREE_MAX_PATH; |
| 440 | |
| 441 | /* Plus branch to fully populated subtrees. */ |
| 442 | nr_nodes += RADIX_TREE_MAX_PATH - subtree_height; |
| 443 | |
| 444 | /* Root node is shared. */ |
| 445 | nr_nodes--; |
| 446 | |
| 447 | /* Plus nodes required to build subtrees. */ |
| 448 | nr_nodes += nr_subtrees * height_to_maxnodes[subtree_height]; |
| 449 | |
| 450 | return __radix_tree_preload(gfp_mask, nr_nodes); |
| 451 | } |
| 452 | |
| 453 | /* |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 454 | * The maximum index which can be stored in a radix tree |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | */ |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 456 | static inline unsigned long shift_maxindex(unsigned int shift) |
| 457 | { |
| 458 | return (RADIX_TREE_MAP_SIZE << shift) - 1; |
| 459 | } |
| 460 | |
Matthew Wilcox | 1456a43 | 2016-05-20 17:02:08 -0700 | [diff] [blame] | 461 | static inline unsigned long node_maxindex(struct radix_tree_node *node) |
| 462 | { |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 463 | return shift_maxindex(node->shift); |
Matthew Wilcox | 1456a43 | 2016-05-20 17:02:08 -0700 | [diff] [blame] | 464 | } |
| 465 | |
| 466 | static unsigned radix_tree_load_root(struct radix_tree_root *root, |
| 467 | struct radix_tree_node **nodep, unsigned long *maxindex) |
| 468 | { |
| 469 | struct radix_tree_node *node = rcu_dereference_raw(root->rnode); |
| 470 | |
| 471 | *nodep = node; |
| 472 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 473 | if (likely(radix_tree_is_internal_node(node))) { |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 474 | node = entry_to_node(node); |
Matthew Wilcox | 1456a43 | 2016-05-20 17:02:08 -0700 | [diff] [blame] | 475 | *maxindex = node_maxindex(node); |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 476 | return node->shift + RADIX_TREE_MAP_SHIFT; |
Matthew Wilcox | 1456a43 | 2016-05-20 17:02:08 -0700 | [diff] [blame] | 477 | } |
| 478 | |
| 479 | *maxindex = 0; |
| 480 | return 0; |
| 481 | } |
| 482 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | /* |
| 484 | * Extend a radix tree so it can store key @index. |
| 485 | */ |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 486 | static int radix_tree_extend(struct radix_tree_root *root, |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 487 | unsigned long index, unsigned int shift) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | { |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 489 | struct radix_tree_node *slot; |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 490 | unsigned int maxshift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | int tag; |
| 492 | |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 493 | /* Figure out what the shift should be. */ |
| 494 | maxshift = shift; |
| 495 | while (index > shift_maxindex(maxshift)) |
| 496 | maxshift += RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 498 | slot = root->rnode; |
| 499 | if (!slot) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | do { |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 503 | struct radix_tree_node *node = radix_tree_node_alloc(root); |
| 504 | |
| 505 | if (!node) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | return -ENOMEM; |
| 507 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | /* Propagate the aggregated tag info into the new root */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 509 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 510 | if (root_tag_get(root, tag)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | tag_set(node, tag, 0); |
| 512 | } |
| 513 | |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 514 | BUG_ON(shift > BITS_PER_LONG); |
| 515 | node->shift = shift; |
Matthew Wilcox | 0c7fa0a | 2016-05-20 17:03:07 -0700 | [diff] [blame] | 516 | node->offset = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | node->count = 1; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 518 | node->parent = NULL; |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 519 | if (radix_tree_is_internal_node(slot)) |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 520 | entry_to_node(slot)->parent = node; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 521 | node->slots[0] = slot; |
Matthew Wilcox | a4db4dc | 2016-05-20 17:03:24 -0700 | [diff] [blame] | 522 | slot = node_to_entry(node); |
| 523 | rcu_assign_pointer(root->rnode, slot); |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 524 | shift += RADIX_TREE_MAP_SHIFT; |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 525 | } while (shift <= maxshift); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | out: |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 527 | return maxshift + RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | } |
| 529 | |
| 530 | /** |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 531 | * __radix_tree_create - create a slot in a radix tree |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | * @root: radix tree root |
| 533 | * @index: index key |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 534 | * @order: index occupies 2^order aligned slots |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 535 | * @nodep: returns node |
| 536 | * @slotp: returns slot |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | * |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 538 | * Create, if necessary, and return the node and slot for an item |
| 539 | * at position @index in the radix tree @root. |
| 540 | * |
| 541 | * Until there is more than one item in the tree, no nodes are |
| 542 | * allocated and @root->rnode is used as a direct slot instead of |
| 543 | * pointing to a node, in which case *@nodep will be NULL. |
| 544 | * |
| 545 | * Returns -ENOMEM, or 0 for success. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | */ |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 547 | int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 548 | unsigned order, struct radix_tree_node **nodep, |
| 549 | void ***slotp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | { |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 551 | struct radix_tree_node *node = NULL, *child; |
| 552 | void **slot = (void **)&root->rnode; |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 553 | unsigned long maxindex; |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 554 | unsigned int shift, offset = 0; |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 555 | unsigned long max = index | ((1UL << order) - 1); |
| 556 | |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 557 | shift = radix_tree_load_root(root, &child, &maxindex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | |
| 559 | /* Make sure the tree is high enough. */ |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 560 | if (max > maxindex) { |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 561 | int error = radix_tree_extend(root, max, shift); |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 562 | if (error < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | return error; |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 564 | shift = error; |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 565 | child = root->rnode; |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 566 | if (order == shift) |
Matthew Wilcox | 49ea6eb | 2016-05-20 17:02:11 -0700 | [diff] [blame] | 567 | shift += RADIX_TREE_MAP_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | } |
| 569 | |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 570 | while (shift > order) { |
Matthew Wilcox | c12e51b | 2016-05-20 17:03:10 -0700 | [diff] [blame] | 571 | shift -= RADIX_TREE_MAP_SHIFT; |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 572 | if (child == NULL) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 573 | /* Have to add a child node. */ |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 574 | child = radix_tree_node_alloc(root); |
| 575 | if (!child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | return -ENOMEM; |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 577 | child->shift = shift; |
| 578 | child->offset = offset; |
| 579 | child->parent = node; |
| 580 | rcu_assign_pointer(*slot, node_to_entry(child)); |
| 581 | if (node) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | node->count++; |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 583 | } else if (!radix_tree_is_internal_node(child)) |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 584 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | |
| 586 | /* Go a level down */ |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 587 | node = entry_to_node(child); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 588 | offset = radix_tree_descend(node, &child, index); |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 589 | slot = &node->slots[offset]; |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 590 | } |
| 591 | |
Matthew Wilcox | 57578c2 | 2016-05-20 17:01:54 -0700 | [diff] [blame] | 592 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 593 | /* Insert pointers to the canonical entry */ |
Matthew Wilcox | 3b8c00f | 2016-05-20 17:01:59 -0700 | [diff] [blame] | 594 | if (order > shift) { |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 595 | unsigned i, n = 1 << (order - shift); |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 596 | offset = offset & ~(n - 1); |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 597 | slot = &node->slots[offset]; |
| 598 | child = node_to_entry(slot); |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 599 | for (i = 0; i < n; i++) { |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 600 | if (slot[i]) |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 601 | return -EEXIST; |
| 602 | } |
| 603 | |
| 604 | for (i = 1; i < n; i++) { |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 605 | rcu_assign_pointer(slot[i], child); |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 606 | node->count++; |
| 607 | } |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 608 | } |
Matthew Wilcox | 57578c2 | 2016-05-20 17:01:54 -0700 | [diff] [blame] | 609 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 611 | if (nodep) |
| 612 | *nodep = node; |
| 613 | if (slotp) |
Matthew Wilcox | 89148aa | 2016-05-20 17:03:42 -0700 | [diff] [blame] | 614 | *slotp = slot; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 615 | return 0; |
| 616 | } |
| 617 | |
| 618 | /** |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 619 | * __radix_tree_insert - insert into a radix tree |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 620 | * @root: radix tree root |
| 621 | * @index: index key |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 622 | * @order: key covers the 2^order indices around index |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 623 | * @item: item to insert |
| 624 | * |
| 625 | * Insert an item into the radix tree at position @index. |
| 626 | */ |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 627 | int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, |
| 628 | unsigned order, void *item) |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 629 | { |
| 630 | struct radix_tree_node *node; |
| 631 | void **slot; |
| 632 | int error; |
| 633 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 634 | BUG_ON(radix_tree_is_internal_node(item)); |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 635 | |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 636 | error = __radix_tree_create(root, index, order, &node, &slot); |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 637 | if (error) |
| 638 | return error; |
| 639 | if (*slot != NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | return -EEXIST; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 641 | rcu_assign_pointer(*slot, item); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 642 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 643 | if (node) { |
Matthew Wilcox | 7b60e9a | 2016-05-20 17:02:23 -0700 | [diff] [blame] | 644 | unsigned offset = get_slot_offset(node, slot); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 645 | node->count++; |
Matthew Wilcox | 7b60e9a | 2016-05-20 17:02:23 -0700 | [diff] [blame] | 646 | BUG_ON(tag_get(node, 0, offset)); |
| 647 | BUG_ON(tag_get(node, 1, offset)); |
| 648 | BUG_ON(tag_get(node, 2, offset)); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 649 | } else { |
Matthew Wilcox | 7b60e9a | 2016-05-20 17:02:23 -0700 | [diff] [blame] | 650 | BUG_ON(root_tags_get(root)); |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 651 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | return 0; |
| 654 | } |
Matthew Wilcox | e614523 | 2016-03-17 14:21:54 -0700 | [diff] [blame] | 655 | EXPORT_SYMBOL(__radix_tree_insert); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 657 | /** |
| 658 | * __radix_tree_lookup - lookup an item in a radix tree |
| 659 | * @root: radix tree root |
| 660 | * @index: index key |
| 661 | * @nodep: returns node |
| 662 | * @slotp: returns slot |
| 663 | * |
| 664 | * Lookup and return the item at position @index in the radix |
| 665 | * tree @root. |
| 666 | * |
| 667 | * Until there is more than one item in the tree, no nodes are |
| 668 | * allocated and @root->rnode is used as a direct slot instead of |
| 669 | * pointing to a node, in which case *@nodep will be NULL. |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 670 | */ |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 671 | void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, |
| 672 | struct radix_tree_node **nodep, void ***slotp) |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 673 | { |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 674 | struct radix_tree_node *node, *parent; |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 675 | unsigned long maxindex; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 676 | void **slot; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 677 | |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 678 | restart: |
| 679 | parent = NULL; |
| 680 | slot = (void **)&root->rnode; |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 681 | radix_tree_load_root(root, &node, &maxindex); |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 682 | if (index > maxindex) |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 683 | return NULL; |
| 684 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 685 | while (radix_tree_is_internal_node(node)) { |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 686 | unsigned offset; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 687 | |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 688 | if (node == RADIX_TREE_RETRY) |
| 689 | goto restart; |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 690 | parent = entry_to_node(node); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 691 | offset = radix_tree_descend(parent, &node, index); |
Matthew Wilcox | 8582995 | 2016-05-20 17:02:20 -0700 | [diff] [blame] | 692 | slot = parent->slots + offset; |
| 693 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 694 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 695 | if (nodep) |
| 696 | *nodep = parent; |
| 697 | if (slotp) |
| 698 | *slotp = slot; |
| 699 | return node; |
Huang Shijie | b72b71c | 2009-06-16 15:33:42 -0700 | [diff] [blame] | 700 | } |
| 701 | |
| 702 | /** |
| 703 | * radix_tree_lookup_slot - lookup a slot in a radix tree |
| 704 | * @root: radix tree root |
| 705 | * @index: index key |
| 706 | * |
| 707 | * Returns: the slot corresponding to the position @index in the |
| 708 | * radix tree @root. This is useful for update-if-exists operations. |
| 709 | * |
| 710 | * This function can be called under rcu_read_lock iff the slot is not |
| 711 | * modified by radix_tree_replace_slot, otherwise it must be called |
| 712 | * exclusive from other writers. Any dereference of the slot must be done |
| 713 | * using radix_tree_deref_slot. |
| 714 | */ |
| 715 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) |
| 716 | { |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 717 | void **slot; |
| 718 | |
| 719 | if (!__radix_tree_lookup(root, index, NULL, &slot)) |
| 720 | return NULL; |
| 721 | return slot; |
Hans Reiser | a433136 | 2005-11-07 00:59:29 -0800 | [diff] [blame] | 722 | } |
| 723 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
| 724 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | /** |
| 726 | * radix_tree_lookup - perform lookup operation on a radix tree |
| 727 | * @root: radix tree root |
| 728 | * @index: index key |
| 729 | * |
| 730 | * Lookup the item at the position @index in the radix tree @root. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 731 | * |
| 732 | * This function can be called under rcu_read_lock, however the caller |
| 733 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free |
| 734 | * them safely). No RCU barriers are required to access or modify the |
| 735 | * returned item, however. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | */ |
| 737 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) |
| 738 | { |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 739 | return __radix_tree_lookup(root, index, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | } |
| 741 | EXPORT_SYMBOL(radix_tree_lookup); |
| 742 | |
| 743 | /** |
| 744 | * radix_tree_tag_set - set a tag on a radix tree node |
| 745 | * @root: radix tree root |
| 746 | * @index: index key |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 747 | * @tag: tag index |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 749 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| 750 | * corresponding to @index in the radix tree. From |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | * the root all the way down to the leaf node. |
| 752 | * |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 753 | * Returns the address of the tagged item. Setting a tag on a not-present |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 754 | * item is a bug. |
| 755 | */ |
| 756 | void *radix_tree_tag_set(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 757 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | { |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 759 | struct radix_tree_node *node, *parent; |
| 760 | unsigned long maxindex; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 761 | |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 762 | radix_tree_load_root(root, &node, &maxindex); |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 763 | BUG_ON(index > maxindex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 765 | while (radix_tree_is_internal_node(node)) { |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 766 | unsigned offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 768 | parent = entry_to_node(node); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 769 | offset = radix_tree_descend(parent, &node, index); |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 770 | BUG_ON(!node); |
| 771 | |
| 772 | if (!tag_get(parent, tag, offset)) |
| 773 | tag_set(parent, tag, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 774 | } |
| 775 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 776 | /* set the root's tag bit */ |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 777 | if (!root_tag_get(root, tag)) |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 778 | root_tag_set(root, tag); |
| 779 | |
Ross Zwisler | fb96990 | 2016-05-20 17:02:32 -0700 | [diff] [blame] | 780 | return node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | } |
| 782 | EXPORT_SYMBOL(radix_tree_tag_set); |
| 783 | |
Matthew Wilcox | d604c32 | 2016-05-20 17:03:45 -0700 | [diff] [blame] | 784 | static void node_tag_clear(struct radix_tree_root *root, |
| 785 | struct radix_tree_node *node, |
| 786 | unsigned int tag, unsigned int offset) |
| 787 | { |
| 788 | while (node) { |
| 789 | if (!tag_get(node, tag, offset)) |
| 790 | return; |
| 791 | tag_clear(node, tag, offset); |
| 792 | if (any_tag_set(node, tag)) |
| 793 | return; |
| 794 | |
| 795 | offset = node->offset; |
| 796 | node = node->parent; |
| 797 | } |
| 798 | |
| 799 | /* clear the root's tag bit */ |
| 800 | if (root_tag_get(root, tag)) |
| 801 | root_tag_clear(root, tag); |
| 802 | } |
| 803 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 804 | /** |
| 805 | * radix_tree_tag_clear - clear a tag on a radix tree node |
| 806 | * @root: radix tree root |
| 807 | * @index: index key |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 808 | * @tag: tag index |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 809 | * |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 810 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 811 | * corresponding to @index in the radix tree. If this causes |
| 812 | * the leaf node to have no tags set then clear the tag in the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | * next-to-leaf node, etc. |
| 814 | * |
| 815 | * Returns the address of the tagged item on success, else NULL. ie: |
| 816 | * has the same return value and semantics as radix_tree_lookup(). |
| 817 | */ |
| 818 | void *radix_tree_tag_clear(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 819 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | { |
Ross Zwisler | 00f47b5 | 2016-05-20 17:02:35 -0700 | [diff] [blame] | 821 | struct radix_tree_node *node, *parent; |
| 822 | unsigned long maxindex; |
Hugh Dickins | e2bdb93 | 2012-01-12 17:20:41 -0800 | [diff] [blame] | 823 | int uninitialized_var(offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 824 | |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 825 | radix_tree_load_root(root, &node, &maxindex); |
Ross Zwisler | 00f47b5 | 2016-05-20 17:02:35 -0700 | [diff] [blame] | 826 | if (index > maxindex) |
| 827 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | |
Ross Zwisler | 00f47b5 | 2016-05-20 17:02:35 -0700 | [diff] [blame] | 829 | parent = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 831 | while (radix_tree_is_internal_node(node)) { |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 832 | parent = entry_to_node(node); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 833 | offset = radix_tree_descend(parent, &node, index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 834 | } |
| 835 | |
Matthew Wilcox | d604c32 | 2016-05-20 17:03:45 -0700 | [diff] [blame] | 836 | if (node) |
| 837 | node_tag_clear(root, parent, tag, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 838 | |
Ross Zwisler | 00f47b5 | 2016-05-20 17:02:35 -0700 | [diff] [blame] | 839 | return node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | } |
| 841 | EXPORT_SYMBOL(radix_tree_tag_clear); |
| 842 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 843 | /** |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 844 | * radix_tree_tag_get - get a tag on a radix tree node |
| 845 | * @root: radix tree root |
| 846 | * @index: index key |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 847 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 848 | * |
Marcelo Tosatti | 32605a1 | 2005-09-06 15:16:48 -0700 | [diff] [blame] | 849 | * Return values: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | * |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 851 | * 0: tag not present or not set |
| 852 | * 1: tag set |
David Howells | ce82653 | 2010-04-06 22:36:20 +0100 | [diff] [blame] | 853 | * |
| 854 | * Note that the return value of this function may not be relied on, even if |
| 855 | * the RCU lock is held, unless tag modification and node deletion are excluded |
| 856 | * from concurrency. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | */ |
| 858 | int radix_tree_tag_get(struct radix_tree_root *root, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 859 | unsigned long index, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | { |
Ross Zwisler | 4589ba6 | 2016-05-20 17:02:38 -0700 | [diff] [blame] | 861 | struct radix_tree_node *node, *parent; |
| 862 | unsigned long maxindex; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 864 | if (!root_tag_get(root, tag)) |
| 865 | return 0; |
| 866 | |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 867 | radix_tree_load_root(root, &node, &maxindex); |
Ross Zwisler | 4589ba6 | 2016-05-20 17:02:38 -0700 | [diff] [blame] | 868 | if (index > maxindex) |
| 869 | return 0; |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 870 | if (node == NULL) |
| 871 | return 0; |
| 872 | |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 873 | while (radix_tree_is_internal_node(node)) { |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 874 | unsigned offset; |
Ross Zwisler | 4589ba6 | 2016-05-20 17:02:38 -0700 | [diff] [blame] | 875 | |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 876 | parent = entry_to_node(node); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 877 | offset = radix_tree_descend(parent, &node, index); |
Ross Zwisler | 4589ba6 | 2016-05-20 17:02:38 -0700 | [diff] [blame] | 878 | |
| 879 | if (!node) |
| 880 | return 0; |
| 881 | if (!tag_get(parent, tag, offset)) |
| 882 | return 0; |
| 883 | if (node == RADIX_TREE_RETRY) |
| 884 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | } |
Ross Zwisler | 4589ba6 | 2016-05-20 17:02:38 -0700 | [diff] [blame] | 886 | |
| 887 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 888 | } |
| 889 | EXPORT_SYMBOL(radix_tree_tag_get); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 891 | static inline void __set_iter_shift(struct radix_tree_iter *iter, |
| 892 | unsigned int shift) |
| 893 | { |
| 894 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| 895 | iter->shift = shift; |
| 896 | #endif |
| 897 | } |
| 898 | |
Fengguang Wu | 6df8ba4 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 899 | /** |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 900 | * radix_tree_next_chunk - find next chunk of slots for iteration |
| 901 | * |
| 902 | * @root: radix tree root |
| 903 | * @iter: iterator state |
| 904 | * @flags: RADIX_TREE_ITER_* flags and tag index |
| 905 | * Returns: pointer to chunk first slot, or NULL if iteration is over |
| 906 | */ |
| 907 | void **radix_tree_next_chunk(struct radix_tree_root *root, |
| 908 | struct radix_tree_iter *iter, unsigned flags) |
| 909 | { |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 910 | unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 911 | struct radix_tree_node *node, *child; |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 912 | unsigned long index, offset, maxindex; |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 913 | |
| 914 | if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) |
| 915 | return NULL; |
| 916 | |
| 917 | /* |
| 918 | * Catch next_index overflow after ~0UL. iter->index never overflows |
| 919 | * during iterating; it can be zero only at the beginning. |
| 920 | * And we cannot overflow iter->next_index in a single step, |
| 921 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. |
Konstantin Khlebnikov | fffaee3 | 2012-06-05 21:36:33 +0400 | [diff] [blame] | 922 | * |
| 923 | * This condition also used by radix_tree_next_slot() to stop |
| 924 | * contiguous iterating, and forbid swithing to the next chunk. |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 925 | */ |
| 926 | index = iter->next_index; |
| 927 | if (!index && iter->index) |
| 928 | return NULL; |
| 929 | |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 930 | restart: |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 931 | radix_tree_load_root(root, &child, &maxindex); |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 932 | if (index > maxindex) |
| 933 | return NULL; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 934 | if (!child) |
| 935 | return NULL; |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 936 | |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 937 | if (!radix_tree_is_internal_node(child)) { |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 938 | /* Single-slot tree */ |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 939 | iter->index = index; |
| 940 | iter->next_index = maxindex + 1; |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 941 | iter->tags = 1; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 942 | __set_iter_shift(iter, 0); |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 943 | return (void **)&root->rnode; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 944 | } |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 945 | |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 946 | do { |
| 947 | node = entry_to_node(child); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 948 | offset = radix_tree_descend(node, &child, index); |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 949 | |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 950 | if ((flags & RADIX_TREE_ITER_TAGGED) ? |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 951 | !tag_get(node, tag, offset) : !child) { |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 952 | /* Hole detected */ |
| 953 | if (flags & RADIX_TREE_ITER_CONTIG) |
| 954 | return NULL; |
| 955 | |
| 956 | if (flags & RADIX_TREE_ITER_TAGGED) |
| 957 | offset = radix_tree_find_next_bit( |
| 958 | node->tags[tag], |
| 959 | RADIX_TREE_MAP_SIZE, |
| 960 | offset + 1); |
| 961 | else |
| 962 | while (++offset < RADIX_TREE_MAP_SIZE) { |
Ross Zwisler | 21ef533 | 2016-05-20 17:02:26 -0700 | [diff] [blame] | 963 | void *slot = node->slots[offset]; |
| 964 | if (is_sibling_entry(node, slot)) |
| 965 | continue; |
| 966 | if (slot) |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 967 | break; |
| 968 | } |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 969 | index &= ~node_maxindex(node); |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 970 | index += offset << node->shift; |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 971 | /* Overflow after ~0UL */ |
| 972 | if (!index) |
| 973 | return NULL; |
| 974 | if (offset == RADIX_TREE_MAP_SIZE) |
| 975 | goto restart; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 976 | child = rcu_dereference_raw(node->slots[offset]); |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 977 | } |
| 978 | |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 979 | if ((child == NULL) || (child == RADIX_TREE_RETRY)) |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 980 | goto restart; |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 981 | } while (radix_tree_is_internal_node(child)); |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 982 | |
| 983 | /* Update the iterator state */ |
Matthew Wilcox | 8c1244d | 2016-05-20 17:03:36 -0700 | [diff] [blame] | 984 | iter->index = (index &~ node_maxindex(node)) | (offset << node->shift); |
| 985 | iter->next_index = (index | node_maxindex(node)) + 1; |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 986 | __set_iter_shift(iter, node->shift); |
Konstantin Khlebnikov | 78c1d78 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 987 | |
| 988 | /* Construct iter->tags bit-mask from node->tags[tag] array */ |
| 989 | if (flags & RADIX_TREE_ITER_TAGGED) { |
| 990 | unsigned tag_long, tag_bit; |
| 991 | |
| 992 | tag_long = offset / BITS_PER_LONG; |
| 993 | tag_bit = offset % BITS_PER_LONG; |
| 994 | iter->tags = node->tags[tag][tag_long] >> tag_bit; |
| 995 | /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ |
| 996 | if (tag_long < RADIX_TREE_TAG_LONGS - 1) { |
| 997 | /* Pick tags from next element */ |
| 998 | if (tag_bit) |
| 999 | iter->tags |= node->tags[tag][tag_long + 1] << |
| 1000 | (BITS_PER_LONG - tag_bit); |
| 1001 | /* Clip chunk size, here only BITS_PER_LONG tags */ |
| 1002 | iter->next_index = index + BITS_PER_LONG; |
| 1003 | } |
| 1004 | } |
| 1005 | |
| 1006 | return node->slots + offset; |
| 1007 | } |
| 1008 | EXPORT_SYMBOL(radix_tree_next_chunk); |
| 1009 | |
| 1010 | /** |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1011 | * radix_tree_range_tag_if_tagged - for each item in given range set given |
| 1012 | * tag if item has another tag set |
| 1013 | * @root: radix tree root |
| 1014 | * @first_indexp: pointer to a starting index of a range to scan |
| 1015 | * @last_index: last index of a range to scan |
| 1016 | * @nr_to_tag: maximum number items to tag |
| 1017 | * @iftag: tag index to test |
| 1018 | * @settag: tag index to set if tested tag is set |
| 1019 | * |
| 1020 | * This function scans range of radix tree from first_index to last_index |
| 1021 | * (inclusive). For each item in the range if iftag is set, the function sets |
| 1022 | * also settag. The function stops either after tagging nr_to_tag items or |
| 1023 | * after reaching last_index. |
| 1024 | * |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1025 | * The tags must be set from the leaf level only and propagated back up the |
| 1026 | * path to the root. We must do this so that we resolve the full path before |
| 1027 | * setting any tags on intermediate nodes. If we set tags as we descend, then |
| 1028 | * we can get to the leaf node and find that the index that has the iftag |
| 1029 | * set is outside the range we are scanning. This reults in dangling tags and |
| 1030 | * can lead to problems with later tag operations (e.g. livelocks on lookups). |
| 1031 | * |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1032 | * The function returns the number of leaves where the tag was set and sets |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1033 | * *first_indexp to the first unscanned index. |
Jan Kara | d5ed3a4 | 2010-08-19 14:13:33 -0700 | [diff] [blame] | 1034 | * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must |
| 1035 | * be prepared to handle that. |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1036 | */ |
| 1037 | unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, |
| 1038 | unsigned long *first_indexp, unsigned long last_index, |
| 1039 | unsigned long nr_to_tag, |
| 1040 | unsigned int iftag, unsigned int settag) |
| 1041 | { |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1042 | struct radix_tree_node *parent, *node, *child; |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1043 | unsigned long maxindex; |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1044 | unsigned long tagged = 0; |
| 1045 | unsigned long index = *first_indexp; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1046 | |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1047 | radix_tree_load_root(root, &child, &maxindex); |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1048 | last_index = min(last_index, maxindex); |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1049 | if (index > last_index) |
| 1050 | return 0; |
| 1051 | if (!nr_to_tag) |
| 1052 | return 0; |
| 1053 | if (!root_tag_get(root, iftag)) { |
| 1054 | *first_indexp = last_index + 1; |
| 1055 | return 0; |
| 1056 | } |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1057 | if (!radix_tree_is_internal_node(child)) { |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1058 | *first_indexp = last_index + 1; |
| 1059 | root_tag_set(root, settag); |
| 1060 | return 1; |
| 1061 | } |
| 1062 | |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1063 | node = entry_to_node(child); |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1064 | |
| 1065 | for (;;) { |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1066 | unsigned offset = radix_tree_descend(node, &child, index); |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1067 | if (!child) |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1068 | goto next; |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1069 | if (!tag_get(node, iftag, offset)) |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1070 | goto next; |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1071 | /* Sibling slots never have tags set on them */ |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1072 | if (radix_tree_is_internal_node(child)) { |
| 1073 | node = entry_to_node(child); |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1074 | continue; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1075 | } |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1076 | |
| 1077 | /* tag the leaf */ |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1078 | tagged++; |
| 1079 | tag_set(node, settag, offset); |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1080 | |
| 1081 | /* walk back up the path tagging interior nodes */ |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1082 | parent = node; |
| 1083 | for (;;) { |
| 1084 | offset = parent->offset; |
| 1085 | parent = parent->parent; |
| 1086 | if (!parent) |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1087 | break; |
Matthew Wilcox | a8e4da2 | 2016-05-20 17:03:39 -0700 | [diff] [blame] | 1088 | /* stop if we find a node with the tag already set */ |
| 1089 | if (tag_get(parent, settag, offset)) |
| 1090 | break; |
| 1091 | tag_set(parent, settag, offset); |
Dave Chinner | 144dcfc | 2010-08-23 10:33:53 +1000 | [diff] [blame] | 1092 | } |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1093 | next: |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1094 | /* Go to next entry in node */ |
| 1095 | index = ((index >> node->shift) + 1) << node->shift; |
Jan Kara | d5ed3a4 | 2010-08-19 14:13:33 -0700 | [diff] [blame] | 1096 | /* Overflow can happen when last_index is ~0UL... */ |
| 1097 | if (index > last_index || !index) |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1098 | break; |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1099 | offset = (index >> node->shift) & RADIX_TREE_MAP_MASK; |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1100 | while (offset == 0) { |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1101 | /* |
| 1102 | * We've fully scanned this node. Go up. Because |
| 1103 | * last_index is guaranteed to be in the tree, what |
| 1104 | * we do below cannot wander astray. |
| 1105 | */ |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1106 | node = node->parent; |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1107 | offset = (index >> node->shift) & RADIX_TREE_MAP_MASK; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1108 | } |
Matthew Wilcox | 070c5ac | 2016-05-20 17:02:52 -0700 | [diff] [blame] | 1109 | if (is_sibling_entry(node, node->slots[offset])) |
| 1110 | goto next; |
| 1111 | if (tagged >= nr_to_tag) |
| 1112 | break; |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1113 | } |
| 1114 | /* |
Toshiyuki Okajima | ac15ee6 | 2011-01-25 15:07:32 -0800 | [diff] [blame] | 1115 | * We need not to tag the root tag if there is no tag which is set with |
| 1116 | * settag within the range from *first_indexp to last_index. |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1117 | */ |
Toshiyuki Okajima | ac15ee6 | 2011-01-25 15:07:32 -0800 | [diff] [blame] | 1118 | if (tagged > 0) |
| 1119 | root_tag_set(root, settag); |
Jan Kara | ebf8aa4 | 2010-08-09 17:19:11 -0700 | [diff] [blame] | 1120 | *first_indexp = index; |
| 1121 | |
| 1122 | return tagged; |
| 1123 | } |
| 1124 | EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); |
| 1125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | /** |
| 1127 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree |
| 1128 | * @root: radix tree root |
| 1129 | * @results: where the results of the lookup are placed |
| 1130 | * @first_index: start the lookup from this key |
| 1131 | * @max_items: place up to this many items at *results |
| 1132 | * |
| 1133 | * Performs an index-ascending scan of the tree for present items. Places |
| 1134 | * them at *@results and returns the number of items which were placed at |
| 1135 | * *@results. |
| 1136 | * |
| 1137 | * The implementation is naive. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1138 | * |
| 1139 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under |
| 1140 | * rcu_read_lock. In this case, rather than the returned results being |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1141 | * an atomic snapshot of the tree at a single point in time, the |
| 1142 | * semantics of an RCU protected gang lookup are as though multiple |
| 1143 | * radix_tree_lookups have been issued in individual locks, and results |
| 1144 | * stored in 'results'. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1145 | */ |
| 1146 | unsigned int |
| 1147 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, |
| 1148 | unsigned long first_index, unsigned int max_items) |
| 1149 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1150 | struct radix_tree_iter iter; |
| 1151 | void **slot; |
| 1152 | unsigned int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1154 | if (unlikely(!max_items)) |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1155 | return 0; |
| 1156 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1157 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
Matthew Wilcox | 46437f9 | 2016-02-02 16:57:52 -0800 | [diff] [blame] | 1158 | results[ret] = rcu_dereference_raw(*slot); |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1159 | if (!results[ret]) |
| 1160 | continue; |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 1161 | if (radix_tree_is_internal_node(results[ret])) { |
Matthew Wilcox | 46437f9 | 2016-02-02 16:57:52 -0800 | [diff] [blame] | 1162 | slot = radix_tree_iter_retry(&iter); |
| 1163 | continue; |
| 1164 | } |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1165 | if (++ret == max_items) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1167 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1168 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1169 | return ret; |
| 1170 | } |
| 1171 | EXPORT_SYMBOL(radix_tree_gang_lookup); |
| 1172 | |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1173 | /** |
| 1174 | * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree |
| 1175 | * @root: radix tree root |
| 1176 | * @results: where the results of the lookup are placed |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1177 | * @indices: where their indices should be placed (but usually NULL) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1178 | * @first_index: start the lookup from this key |
| 1179 | * @max_items: place up to this many items at *results |
| 1180 | * |
| 1181 | * Performs an index-ascending scan of the tree for present items. Places |
| 1182 | * their slots at *@results and returns the number of items which were |
| 1183 | * placed at *@results. |
| 1184 | * |
| 1185 | * The implementation is naive. |
| 1186 | * |
| 1187 | * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must |
| 1188 | * be dereferenced with radix_tree_deref_slot, and if using only RCU |
| 1189 | * protection, radix_tree_deref_slot may fail requiring a retry. |
| 1190 | */ |
| 1191 | unsigned int |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1192 | radix_tree_gang_lookup_slot(struct radix_tree_root *root, |
| 1193 | void ***results, unsigned long *indices, |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1194 | unsigned long first_index, unsigned int max_items) |
| 1195 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1196 | struct radix_tree_iter iter; |
| 1197 | void **slot; |
| 1198 | unsigned int ret = 0; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1199 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1200 | if (unlikely(!max_items)) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1201 | return 0; |
| 1202 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1203 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
| 1204 | results[ret] = slot; |
Hugh Dickins | 6328650 | 2011-08-03 16:21:18 -0700 | [diff] [blame] | 1205 | if (indices) |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1206 | indices[ret] = iter.index; |
| 1207 | if (++ret == max_items) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1208 | break; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1209 | } |
| 1210 | |
| 1211 | return ret; |
| 1212 | } |
| 1213 | EXPORT_SYMBOL(radix_tree_gang_lookup_slot); |
| 1214 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1215 | /** |
| 1216 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree |
| 1217 | * based on a tag |
| 1218 | * @root: radix tree root |
| 1219 | * @results: where the results of the lookup are placed |
| 1220 | * @first_index: start the lookup from this key |
| 1221 | * @max_items: place up to this many items at *results |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1222 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1223 | * |
| 1224 | * Performs an index-ascending scan of the tree for present items which |
| 1225 | * have the tag indexed by @tag set. Places the items at *@results and |
| 1226 | * returns the number of items which were placed at *@results. |
| 1227 | */ |
| 1228 | unsigned int |
| 1229 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1230 | unsigned long first_index, unsigned int max_items, |
| 1231 | unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1233 | struct radix_tree_iter iter; |
| 1234 | void **slot; |
| 1235 | unsigned int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1236 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1237 | if (unlikely(!max_items)) |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1238 | return 0; |
| 1239 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1240 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
Matthew Wilcox | 46437f9 | 2016-02-02 16:57:52 -0800 | [diff] [blame] | 1241 | results[ret] = rcu_dereference_raw(*slot); |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1242 | if (!results[ret]) |
| 1243 | continue; |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 1244 | if (radix_tree_is_internal_node(results[ret])) { |
Matthew Wilcox | 46437f9 | 2016-02-02 16:57:52 -0800 | [diff] [blame] | 1245 | slot = radix_tree_iter_retry(&iter); |
| 1246 | continue; |
| 1247 | } |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1248 | if (++ret == max_items) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1249 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | } |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1251 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1252 | return ret; |
| 1253 | } |
| 1254 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); |
| 1255 | |
| 1256 | /** |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1257 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a |
| 1258 | * radix tree based on a tag |
| 1259 | * @root: radix tree root |
| 1260 | * @results: where the results of the lookup are placed |
| 1261 | * @first_index: start the lookup from this key |
| 1262 | * @max_items: place up to this many items at *results |
| 1263 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
| 1264 | * |
| 1265 | * Performs an index-ascending scan of the tree for present items which |
| 1266 | * have the tag indexed by @tag set. Places the slots at *@results and |
| 1267 | * returns the number of slots which were placed at *@results. |
| 1268 | */ |
| 1269 | unsigned int |
| 1270 | radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, |
| 1271 | unsigned long first_index, unsigned int max_items, |
| 1272 | unsigned int tag) |
| 1273 | { |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1274 | struct radix_tree_iter iter; |
| 1275 | void **slot; |
| 1276 | unsigned int ret = 0; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1277 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1278 | if (unlikely(!max_items)) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1279 | return 0; |
| 1280 | |
Konstantin Khlebnikov | cebbd29 | 2012-03-28 14:42:53 -0700 | [diff] [blame] | 1281 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
| 1282 | results[ret] = slot; |
| 1283 | if (++ret == max_items) |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1284 | break; |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1285 | } |
| 1286 | |
| 1287 | return ret; |
| 1288 | } |
| 1289 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); |
| 1290 | |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1291 | #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP) |
| 1292 | #include <linux/sched.h> /* for cond_resched() */ |
| 1293 | |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1294 | struct locate_info { |
| 1295 | unsigned long found_index; |
| 1296 | bool stop; |
| 1297 | }; |
| 1298 | |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1299 | /* |
| 1300 | * This linear search is at present only useful to shmem_unuse_inode(). |
| 1301 | */ |
| 1302 | static unsigned long __locate(struct radix_tree_node *slot, void *item, |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1303 | unsigned long index, struct locate_info *info) |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1304 | { |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1305 | unsigned long i; |
| 1306 | |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1307 | do { |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1308 | unsigned int shift = slot->shift; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1309 | |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1310 | for (i = (index >> shift) & RADIX_TREE_MAP_MASK; |
| 1311 | i < RADIX_TREE_MAP_SIZE; |
| 1312 | i++, index += (1UL << shift)) { |
| 1313 | struct radix_tree_node *node = |
| 1314 | rcu_dereference_raw(slot->slots[i]); |
| 1315 | if (node == RADIX_TREE_RETRY) |
| 1316 | goto out; |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 1317 | if (!radix_tree_is_internal_node(node)) { |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1318 | if (node == item) { |
| 1319 | info->found_index = index; |
| 1320 | info->stop = true; |
| 1321 | goto out; |
| 1322 | } |
| 1323 | continue; |
| 1324 | } |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 1325 | node = entry_to_node(node); |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1326 | if (is_sibling_entry(slot, node)) |
| 1327 | continue; |
| 1328 | slot = node; |
| 1329 | break; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1330 | } |
Matthew Wilcox | 9e85d81 | 2016-05-20 17:03:48 -0700 | [diff] [blame] | 1331 | } while (i < RADIX_TREE_MAP_SIZE); |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1332 | |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1333 | out: |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1334 | if ((index == 0) && (i == RADIX_TREE_MAP_SIZE)) |
| 1335 | info->stop = true; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1336 | return index; |
| 1337 | } |
| 1338 | |
| 1339 | /** |
| 1340 | * radix_tree_locate_item - search through radix tree for item |
| 1341 | * @root: radix tree root |
| 1342 | * @item: item to be found |
| 1343 | * |
| 1344 | * Returns index where item was found, or -1 if not found. |
| 1345 | * Caller must hold no lock (since this time-consuming function needs |
| 1346 | * to be preemptible), and must check afterwards if item is still there. |
| 1347 | */ |
| 1348 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) |
| 1349 | { |
| 1350 | struct radix_tree_node *node; |
| 1351 | unsigned long max_index; |
| 1352 | unsigned long cur_index = 0; |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1353 | struct locate_info info = { |
| 1354 | .found_index = -1, |
| 1355 | .stop = false, |
| 1356 | }; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1357 | |
| 1358 | do { |
| 1359 | rcu_read_lock(); |
| 1360 | node = rcu_dereference_raw(root->rnode); |
Matthew Wilcox | b194d16 | 2016-05-20 17:03:30 -0700 | [diff] [blame] | 1361 | if (!radix_tree_is_internal_node(node)) { |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1362 | rcu_read_unlock(); |
| 1363 | if (node == item) |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1364 | info.found_index = 0; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1365 | break; |
| 1366 | } |
| 1367 | |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 1368 | node = entry_to_node(node); |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1369 | |
| 1370 | max_index = node_maxindex(node); |
Hugh Dickins | 5f30fc9 | 2014-03-03 15:38:23 -0800 | [diff] [blame] | 1371 | if (cur_index > max_index) { |
| 1372 | rcu_read_unlock(); |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1373 | break; |
Hugh Dickins | 5f30fc9 | 2014-03-03 15:38:23 -0800 | [diff] [blame] | 1374 | } |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1375 | |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1376 | cur_index = __locate(node, item, cur_index, &info); |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1377 | rcu_read_unlock(); |
| 1378 | cond_resched(); |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1379 | } while (!info.stop && cur_index <= max_index); |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1380 | |
Matthew Wilcox | 0a2efc6 | 2016-05-20 17:02:46 -0700 | [diff] [blame] | 1381 | return info.found_index; |
Hugh Dickins | e504f3f | 2011-08-03 16:21:27 -0700 | [diff] [blame] | 1382 | } |
| 1383 | #else |
| 1384 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) |
| 1385 | { |
| 1386 | return -1; |
| 1387 | } |
| 1388 | #endif /* CONFIG_SHMEM && CONFIG_SWAP */ |
Nick Piggin | 47feff2 | 2008-07-25 19:45:29 -0700 | [diff] [blame] | 1389 | |
| 1390 | /** |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 1391 | * radix_tree_shrink - shrink radix tree to minimum height |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1392 | * @root radix tree root |
| 1393 | */ |
Matthew Wilcox | fb20901 | 2016-05-20 17:03:13 -0700 | [diff] [blame] | 1394 | static inline bool radix_tree_shrink(struct radix_tree_root *root) |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1395 | { |
Matthew Wilcox | fb20901 | 2016-05-20 17:03:13 -0700 | [diff] [blame] | 1396 | bool shrunk = false; |
| 1397 | |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 1398 | for (;;) { |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1399 | struct radix_tree_node *node = root->rnode; |
| 1400 | struct radix_tree_node *child; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1401 | |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1402 | if (!radix_tree_is_internal_node(node)) |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 1403 | break; |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1404 | node = entry_to_node(node); |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1405 | |
| 1406 | /* |
| 1407 | * The candidate node has more than one child, or its child |
Matthew Wilcox | d089126 | 2016-05-20 17:03:19 -0700 | [diff] [blame] | 1408 | * is not at the leftmost slot, or the child is a multiorder |
| 1409 | * entry, we cannot shrink. |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1410 | */ |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1411 | if (node->count != 1) |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1412 | break; |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1413 | child = node->slots[0]; |
| 1414 | if (!child) |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1415 | break; |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1416 | if (!radix_tree_is_internal_node(child) && node->shift) |
Matthew Wilcox | afe0e39 | 2016-05-20 17:02:17 -0700 | [diff] [blame] | 1417 | break; |
| 1418 | |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1419 | if (radix_tree_is_internal_node(child)) |
| 1420 | entry_to_node(child)->parent = NULL; |
Nick Piggin | c0bc987 | 2007-10-16 01:24:42 -0700 | [diff] [blame] | 1421 | |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1422 | /* |
| 1423 | * We don't need rcu_assign_pointer(), since we are simply |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1424 | * moving the node from one part of the tree to another: if it |
| 1425 | * was safe to dereference the old pointer to it |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1426 | * (node->slots[0]), it will be safe to dereference the new |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1427 | * one (root->rnode) as far as dependent read barriers go. |
Nick Piggin | 7cf9c2c | 2006-12-06 20:33:44 -0800 | [diff] [blame] | 1428 | */ |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1429 | root->rnode = child; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1430 | |
| 1431 | /* |
| 1432 | * We have a dilemma here. The node's slot[0] must not be |
| 1433 | * NULLed in case there are concurrent lookups expecting to |
| 1434 | * find the item. However if this was a bottom-level node, |
| 1435 | * then it may be subject to the slot pointer being visible |
| 1436 | * to callers dereferencing it. If item corresponding to |
| 1437 | * slot[0] is subsequently deleted, these callers would expect |
| 1438 | * their slot to become empty sooner or later. |
| 1439 | * |
| 1440 | * For example, lockless pagecache will look up a slot, deref |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1441 | * the page pointer, and if the page has 0 refcount it means it |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1442 | * was concurrently deleted from pagecache so try the deref |
| 1443 | * again. Fortunately there is already a requirement for logic |
| 1444 | * to retry the entire slot lookup -- the indirect pointer |
| 1445 | * problem (replacing direct root node with an indirect pointer |
| 1446 | * also results in a stale slot). So tag the slot as indirect |
| 1447 | * to force callers to retry. |
| 1448 | */ |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1449 | if (!radix_tree_is_internal_node(child)) |
| 1450 | node->slots[0] = RADIX_TREE_RETRY; |
Nick Piggin | 27d20fd | 2010-11-11 14:05:19 -0800 | [diff] [blame] | 1451 | |
Matthew Wilcox | af49a63 | 2016-05-20 17:03:33 -0700 | [diff] [blame] | 1452 | radix_tree_node_free(node); |
Matthew Wilcox | fb20901 | 2016-05-20 17:03:13 -0700 | [diff] [blame] | 1453 | shrunk = true; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1454 | } |
Matthew Wilcox | fb20901 | 2016-05-20 17:03:13 -0700 | [diff] [blame] | 1455 | |
| 1456 | return shrunk; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1457 | } |
| 1458 | |
| 1459 | /** |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1460 | * __radix_tree_delete_node - try to free node after clearing a slot |
| 1461 | * @root: radix tree root |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1462 | * @node: node containing @index |
| 1463 | * |
| 1464 | * After clearing the slot at @index in @node from radix tree |
| 1465 | * rooted at @root, call this function to attempt freeing the |
| 1466 | * node and shrinking the tree. |
| 1467 | * |
| 1468 | * Returns %true if @node was freed, %false otherwise. |
| 1469 | */ |
Johannes Weiner | 449dd69 | 2014-04-03 14:47:56 -0700 | [diff] [blame] | 1470 | bool __radix_tree_delete_node(struct radix_tree_root *root, |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1471 | struct radix_tree_node *node) |
| 1472 | { |
| 1473 | bool deleted = false; |
| 1474 | |
| 1475 | do { |
| 1476 | struct radix_tree_node *parent; |
| 1477 | |
| 1478 | if (node->count) { |
Matthew Wilcox | 4dd6c09 | 2016-05-20 17:03:27 -0700 | [diff] [blame] | 1479 | if (node == entry_to_node(root->rnode)) |
Matthew Wilcox | fb20901 | 2016-05-20 17:03:13 -0700 | [diff] [blame] | 1480 | deleted |= radix_tree_shrink(root); |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1481 | return deleted; |
| 1482 | } |
| 1483 | |
| 1484 | parent = node->parent; |
| 1485 | if (parent) { |
Matthew Wilcox | 0c7fa0a | 2016-05-20 17:03:07 -0700 | [diff] [blame] | 1486 | parent->slots[node->offset] = NULL; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1487 | parent->count--; |
| 1488 | } else { |
| 1489 | root_tag_clear_all(root); |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1490 | root->rnode = NULL; |
| 1491 | } |
| 1492 | |
| 1493 | radix_tree_node_free(node); |
| 1494 | deleted = true; |
| 1495 | |
| 1496 | node = parent; |
| 1497 | } while (node); |
| 1498 | |
| 1499 | return deleted; |
| 1500 | } |
| 1501 | |
Matthew Wilcox | 57578c2 | 2016-05-20 17:01:54 -0700 | [diff] [blame] | 1502 | static inline void delete_sibling_entries(struct radix_tree_node *node, |
| 1503 | void *ptr, unsigned offset) |
| 1504 | { |
| 1505 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| 1506 | int i; |
| 1507 | for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { |
| 1508 | if (node->slots[offset + i] != ptr) |
| 1509 | break; |
| 1510 | node->slots[offset + i] = NULL; |
| 1511 | node->count--; |
| 1512 | } |
| 1513 | #endif |
| 1514 | } |
| 1515 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1516 | /** |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1517 | * radix_tree_delete_item - delete an item from a radix tree |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | * @root: radix tree root |
| 1519 | * @index: index key |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1520 | * @item: expected item |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1521 | * |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1522 | * Remove @item at @index from the radix tree rooted at @root. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1523 | * |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1524 | * Returns the address of the deleted item, or NULL if it was not present |
| 1525 | * or the entry at the given @index was not @item. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1526 | */ |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1527 | void *radix_tree_delete_item(struct radix_tree_root *root, |
| 1528 | unsigned long index, void *item) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1529 | { |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1530 | struct radix_tree_node *node; |
Matthew Wilcox | 57578c2 | 2016-05-20 17:01:54 -0700 | [diff] [blame] | 1531 | unsigned int offset; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1532 | void **slot; |
| 1533 | void *entry; |
Nick Piggin | d527426 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1534 | int tag; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1535 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1536 | entry = __radix_tree_lookup(root, index, &node, &slot); |
| 1537 | if (!entry) |
| 1538 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1539 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1540 | if (item && entry != item) |
| 1541 | return NULL; |
| 1542 | |
| 1543 | if (!node) { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1544 | root_tag_clear_all(root); |
| 1545 | root->rnode = NULL; |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1546 | return entry; |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1547 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1548 | |
Matthew Wilcox | 29e0967 | 2016-05-20 17:02:02 -0700 | [diff] [blame] | 1549 | offset = get_slot_offset(node, slot); |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1550 | |
Matthew Wilcox | d604c32 | 2016-05-20 17:03:45 -0700 | [diff] [blame] | 1551 | /* Clear all tags associated with the item to be deleted. */ |
| 1552 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| 1553 | node_tag_clear(root, node, tag, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1554 | |
Matthew Wilcox | a4db4dc | 2016-05-20 17:03:24 -0700 | [diff] [blame] | 1555 | delete_sibling_entries(node, node_to_entry(slot), offset); |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1556 | node->slots[offset] = NULL; |
| 1557 | node->count--; |
Nick Piggin | a5f51c9 | 2006-01-08 01:01:41 -0800 | [diff] [blame] | 1558 | |
Johannes Weiner | 449dd69 | 2014-04-03 14:47:56 -0700 | [diff] [blame] | 1559 | __radix_tree_delete_node(root, node); |
Christoph Lameter | 201b626 | 2005-09-06 15:16:46 -0700 | [diff] [blame] | 1560 | |
Johannes Weiner | 139e561 | 2014-04-03 14:47:54 -0700 | [diff] [blame] | 1561 | return entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | } |
Johannes Weiner | 53c59f2 | 2014-04-03 14:47:39 -0700 | [diff] [blame] | 1563 | EXPORT_SYMBOL(radix_tree_delete_item); |
| 1564 | |
| 1565 | /** |
| 1566 | * radix_tree_delete - delete an item from a radix tree |
| 1567 | * @root: radix tree root |
| 1568 | * @index: index key |
| 1569 | * |
| 1570 | * Remove the item at @index from the radix tree rooted at @root. |
| 1571 | * |
| 1572 | * Returns the address of the deleted item, or NULL if it was not present. |
| 1573 | */ |
| 1574 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) |
| 1575 | { |
| 1576 | return radix_tree_delete_item(root, index, NULL); |
| 1577 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1578 | EXPORT_SYMBOL(radix_tree_delete); |
| 1579 | |
Matthew Wilcox | d604c32 | 2016-05-20 17:03:45 -0700 | [diff] [blame] | 1580 | struct radix_tree_node *radix_tree_replace_clear_tags( |
| 1581 | struct radix_tree_root *root, |
| 1582 | unsigned long index, void *entry) |
| 1583 | { |
| 1584 | struct radix_tree_node *node; |
| 1585 | void **slot; |
| 1586 | |
| 1587 | __radix_tree_lookup(root, index, &node, &slot); |
| 1588 | |
| 1589 | if (node) { |
| 1590 | unsigned int tag, offset = get_slot_offset(node, slot); |
| 1591 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| 1592 | node_tag_clear(root, node, tag, offset); |
| 1593 | } else { |
| 1594 | /* Clear root node tags */ |
| 1595 | root->gfp_mask &= __GFP_BITS_MASK; |
| 1596 | } |
| 1597 | |
| 1598 | radix_tree_replace_slot(slot, entry); |
| 1599 | return node; |
| 1600 | } |
| 1601 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1602 | /** |
| 1603 | * radix_tree_tagged - test whether any items in the tree are tagged |
| 1604 | * @root: radix tree root |
| 1605 | * @tag: tag to test |
| 1606 | */ |
Jonathan Corbet | daff89f | 2006-03-25 03:08:05 -0800 | [diff] [blame] | 1607 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | { |
Nick Piggin | 612d6c1 | 2006-06-23 02:03:22 -0700 | [diff] [blame] | 1609 | return root_tag_get(root, tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1610 | } |
| 1611 | EXPORT_SYMBOL(radix_tree_tagged); |
| 1612 | |
| 1613 | static void |
Johannes Weiner | 449dd69 | 2014-04-03 14:47:56 -0700 | [diff] [blame] | 1614 | radix_tree_node_ctor(void *arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1615 | { |
Johannes Weiner | 449dd69 | 2014-04-03 14:47:56 -0700 | [diff] [blame] | 1616 | struct radix_tree_node *node = arg; |
| 1617 | |
| 1618 | memset(node, 0, sizeof(*node)); |
| 1619 | INIT_LIST_HEAD(&node->private_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1620 | } |
| 1621 | |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 1622 | static __init unsigned long __maxindex(unsigned int height) |
| 1623 | { |
| 1624 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
| 1625 | int shift = RADIX_TREE_INDEX_BITS - width; |
| 1626 | |
| 1627 | if (shift < 0) |
| 1628 | return ~0UL; |
| 1629 | if (shift >= BITS_PER_LONG) |
| 1630 | return 0UL; |
| 1631 | return ~0UL >> shift; |
| 1632 | } |
| 1633 | |
| 1634 | static __init void radix_tree_init_maxnodes(void) |
| 1635 | { |
| 1636 | unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1]; |
| 1637 | unsigned int i, j; |
| 1638 | |
| 1639 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) |
| 1640 | height_to_maxindex[i] = __maxindex(i); |
| 1641 | for (i = 0; i < ARRAY_SIZE(height_to_maxnodes); i++) { |
| 1642 | for (j = i; j > 0; j--) |
| 1643 | height_to_maxnodes[i] += height_to_maxindex[j - 1] + 1; |
| 1644 | } |
| 1645 | } |
| 1646 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | static int radix_tree_callback(struct notifier_block *nfb, |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1648 | unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1649 | { |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1650 | int cpu = (long)hcpu; |
| 1651 | struct radix_tree_preload *rtp; |
| 1652 | struct radix_tree_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1653 | |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1654 | /* Free per-cpu pool of preloaded nodes */ |
| 1655 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
| 1656 | rtp = &per_cpu(radix_tree_preloads, cpu); |
| 1657 | while (rtp->nr) { |
Kirill A. Shutemov | 9d2a8da | 2015-06-25 15:02:19 -0700 | [diff] [blame] | 1658 | node = rtp->nodes; |
| 1659 | rtp->nodes = node->private_data; |
| 1660 | kmem_cache_free(radix_tree_node_cachep, node); |
| 1661 | rtp->nr--; |
Matthew Wilcox | 2fcd900 | 2016-05-20 17:03:04 -0700 | [diff] [blame] | 1662 | } |
| 1663 | } |
| 1664 | return NOTIFY_OK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1665 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1666 | |
| 1667 | void __init radix_tree_init(void) |
| 1668 | { |
| 1669 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
| 1670 | sizeof(struct radix_tree_node), 0, |
Christoph Lameter | 488514d | 2008-04-28 02:12:05 -0700 | [diff] [blame] | 1671 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
| 1672 | radix_tree_node_ctor); |
Kirill A. Shutemov | c78c66d | 2016-07-26 15:26:02 -0700 | [diff] [blame] | 1673 | radix_tree_init_maxnodes(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1674 | hotcpu_notifier(radix_tree_callback, 0); |
| 1675 | } |