| 1 | #ifndef _LINUX_GENERIC_RADIX_TREE_H
|
| 2 | #define _LINUX_GENERIC_RADIX_TREE_H
|
| 3 |
|
| 4 | |
| 5 | * DOC: Generic radix trees/sparse arrays
|
| 6 | *
|
| 7 | * Very simple and minimalistic, supporting arbitrary size entries up to
|
| 8 | * GENRADIX_NODE_SIZE.
|
| 9 | *
|
| 10 | * A genradix is defined with the type it will store, like so:
|
| 11 | *
|
| 12 | * static GENRADIX(struct foo) foo_genradix;
|
| 13 | *
|
| 14 | * The main operations are:
|
| 15 | *
|
| 16 | * - genradix_init(radix) - initialize an empty genradix
|
| 17 | *
|
| 18 | * - genradix_free(radix) - free all memory owned by the genradix and
|
| 19 | * reinitialize it
|
| 20 | *
|
| 21 | * - genradix_ptr(radix, idx) - gets a pointer to the entry at idx, returning
|
| 22 | * NULL if that entry does not exist
|
| 23 | *
|
| 24 | * - genradix_ptr_alloc(radix, idx, gfp) - gets a pointer to an entry,
|
| 25 | * allocating it if necessary
|
| 26 | *
|
| 27 | * - genradix_for_each(radix, iter, p) - iterate over each entry in a genradix
|
| 28 | *
|
| 29 | * The radix tree allocates one page of entries at a time, so entries may exist
|
| 30 | * that were never explicitly allocated - they will be initialized to all
|
| 31 | * zeroes.
|
| 32 | *
|
| 33 | * Internally, a genradix is just a radix tree of pages, and indexing works in
|
| 34 | * terms of byte offsets. The wrappers in this header file use sizeof on the
|
| 35 | * type the radix contains to calculate a byte offset from the index - see
|
| 36 | * __idx_to_offset.
|
| 37 |
|
| 38 |
|
| 39 | #include <asm/page.h>
|
| 40 | #include <linux/bug.h>
|
| 41 | #include <linux/limits.h>
|
| 42 | #include <linux/log2.h>
|
| 43 | #include <linux/math.h>
|
| 44 | #include <linux/slab.h>
|
| 45 | #include <linux/types.h>
|
| 46 |
|
| 47 | struct genradix_root;
|
| 48 |
|
| 49 | #define GENRADIX_NODE_SHIFT 9
|
| 50 | #define GENRADIX_NODE_SIZE (1U << GENRADIX_NODE_SHIFT)
|
| 51 |
|
| 52 | #define GENRADIX_ARY (GENRADIX_NODE_SIZE / sizeof(struct genradix_node *))
|
| 53 | #define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
|
| 54 |
|
| 55 |
|
| 56 | #define GENRADIX_MAX_DEPTH \
|
| 57 | DIV_ROUND_UP(BITS_PER_LONG - GENRADIX_NODE_SHIFT, GENRADIX_ARY_SHIFT)
|
| 58 |
|
| 59 | #define GENRADIX_DEPTH_MASK \
|
| 60 | ((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
|
| 61 |
|
| 62 | static inline int genradix_depth_shift(unsigned depth)
|
| 63 | {
|
| 64 | return GENRADIX_NODE_SHIFT + GENRADIX_ARY_SHIFT * depth;
|
| 65 | }
|
| 66 |
|
| 67 | |
| 68 | * Returns size (of data, in bytes) that a tree of a given depth holds:
|
| 69 |
|
| 70 | static inline size_t genradix_depth_size(unsigned depth)
|
| 71 | {
|
| 72 | return 1UL << genradix_depth_shift(depth);
|
| 73 | }
|
| 74 |
|
| 75 | static inline unsigned genradix_root_to_depth(struct genradix_root *r)
|
| 76 | {
|
| 77 | return (unsigned long) r & GENRADIX_DEPTH_MASK;
|
| 78 | }
|
| 79 |
|
| 80 | static inline struct genradix_node *genradix_root_to_node(struct genradix_root *r)
|
| 81 | {
|
| 82 | return (void *) ((unsigned long) r & ~GENRADIX_DEPTH_MASK);
|
| 83 | }
|
| 84 |
|
| 85 | struct __genradix {
|
| 86 | struct genradix_root *root;
|
| 87 | };
|
| 88 |
|
| 89 | struct genradix_node {
|
| 90 | union {
|
| 91 |
|
| 92 | struct genradix_node *children[GENRADIX_ARY];
|
| 93 |
|
| 94 |
|
| 95 | u8 data[GENRADIX_NODE_SIZE];
|
| 96 | };
|
| 97 | };
|
| 98 |
|
| 99 | static inline struct genradix_node *genradix_alloc_node(gfp_t gfp_mask)
|
| 100 | {
|
| 101 | return kzalloc(GENRADIX_NODE_SIZE, gfp_mask);
|
| 102 | }
|
| 103 |
|
| 104 | static inline void genradix_free_node(struct genradix_node *node)
|
| 105 | {
|
| 106 | kfree(node);
|
| 107 | }
|
| 108 |
|
| 109 | |
| 110 | * NOTE: currently, sizeof(_type) must not be larger than GENRADIX_NODE_SIZE:
|
| 111 |
|
| 112 |
|
| 113 | #define __GENRADIX_INITIALIZER \
|
| 114 | { \
|
| 115 | .tree = { \
|
| 116 | .root = NULL, \
|
| 117 | } \
|
| 118 | }
|
| 119 |
|
| 120 | |
| 121 | * We use a 0 size array to stash the type we're storing without taking any
|
| 122 | * space at runtime - then the various accessor macros can use typeof() to get
|
| 123 | * to it for casts/sizeof - we also force the alignment so that storing a type
|
| 124 | * with a ridiculous alignment doesn't blow up the alignment or size of the
|
| 125 | * genradix.
|
| 126 |
|
| 127 |
|
| 128 | #define GENRADIX(_type) \
|
| 129 | struct { \
|
| 130 | struct __genradix tree; \
|
| 131 | _type type[0] __aligned(1); \
|
| 132 | }
|
| 133 |
|
| 134 | #define DEFINE_GENRADIX(_name, _type) \
|
| 135 | GENRADIX(_type) _name = __GENRADIX_INITIALIZER
|
| 136 |
|
| 137 | |
| 138 | * genradix_init - initialize a genradix
|
| 139 | * @_radix: genradix to initialize
|
| 140 | *
|
| 141 | * Does not fail
|
| 142 |
|
| 143 | #define genradix_init(_radix) \
|
| 144 | do { \
|
| 145 | *(_radix) = (typeof(*_radix)) __GENRADIX_INITIALIZER; \
|
| 146 | } while (0)
|
| 147 |
|
| 148 | void __genradix_free(struct __genradix *);
|
| 149 |
|
| 150 | |
| 151 | * genradix_free: free all memory owned by a genradix
|
| 152 | * @_radix: the genradix to free
|
| 153 | *
|
| 154 | * After freeing, @_radix will be reinitialized and empty
|
| 155 |
|
| 156 | #define genradix_free(_radix) __genradix_free(&(_radix)->tree)
|
| 157 |
|
| 158 | static inline size_t __idx_to_offset(size_t idx, size_t obj_size)
|
| 159 | {
|
| 160 | if (__builtin_constant_p(obj_size))
|
| 161 | BUILD_BUG_ON(obj_size > GENRADIX_NODE_SIZE);
|
| 162 | else
|
| 163 | BUG_ON(obj_size > GENRADIX_NODE_SIZE);
|
| 164 |
|
| 165 | if (!is_power_of_2(obj_size)) {
|
| 166 | size_t objs_per_page = GENRADIX_NODE_SIZE / obj_size;
|
| 167 |
|
| 168 | return (idx / objs_per_page) * GENRADIX_NODE_SIZE +
|
| 169 | (idx % objs_per_page) * obj_size;
|
| 170 | } else {
|
| 171 | return idx * obj_size;
|
| 172 | }
|
| 173 | }
|
| 174 |
|
| 175 | #define __genradix_cast(_radix) (typeof((_radix)->type[0]) *)
|
| 176 | #define __genradix_obj_size(_radix) sizeof((_radix)->type[0])
|
| 177 | #define __genradix_objs_per_page(_radix) \
|
| 178 | (GENRADIX_NODE_SIZE / sizeof((_radix)->type[0]))
|
| 179 | #define __genradix_page_remainder(_radix) \
|
| 180 | (GENRADIX_NODE_SIZE % sizeof((_radix)->type[0]))
|
| 181 |
|
| 182 | #define __genradix_idx_to_offset(_radix, _idx) \
|
| 183 | __idx_to_offset(_idx, __genradix_obj_size(_radix))
|
| 184 |
|
| 185 | static inline void *__genradix_ptr_inlined(struct __genradix *radix, size_t offset)
|
| 186 | {
|
| 187 | struct genradix_root *r = READ_ONCE(radix->root);
|
| 188 | struct genradix_node *n = genradix_root_to_node(r);
|
| 189 | unsigned level = genradix_root_to_depth(r);
|
| 190 | unsigned shift = genradix_depth_shift(level);
|
| 191 |
|
| 192 | if (unlikely(ilog2(offset) >= genradix_depth_shift(level)))
|
| 193 | return NULL;
|
| 194 |
|
| 195 | while (n && shift > GENRADIX_NODE_SHIFT) {
|
| 196 | shift -= GENRADIX_ARY_SHIFT;
|
| 197 | n = n->children[offset >> shift];
|
| 198 | offset &= (1UL << shift) - 1;
|
| 199 | }
|
| 200 |
|
| 201 | return n ? &n->data[offset] : NULL;
|
| 202 | }
|
| 203 |
|
| 204 | #define genradix_ptr_inlined(_radix, _idx) \
|
| 205 | (__genradix_cast(_radix) \
|
| 206 | __genradix_ptr_inlined(&(_radix)->tree, \
|
| 207 | __genradix_idx_to_offset(_radix, _idx)))
|
| 208 |
|
| 209 | void *__genradix_ptr(struct __genradix *, size_t);
|
| 210 |
|
| 211 | |
| 212 | * genradix_ptr - get a pointer to a genradix entry
|
| 213 | * @_radix: genradix to access
|
| 214 | * @_idx: index to fetch
|
| 215 | *
|
| 216 | * Returns a pointer to entry at @_idx, or NULL if that entry does not exist.
|
| 217 |
|
| 218 | #define genradix_ptr(_radix, _idx) \
|
| 219 | (__genradix_cast(_radix) \
|
| 220 | __genradix_ptr(&(_radix)->tree, \
|
| 221 | __genradix_idx_to_offset(_radix, _idx)))
|
| 222 |
|
| 223 | void *__genradix_ptr_alloc(struct __genradix *, size_t,
|
| 224 | struct genradix_node **, gfp_t);
|
| 225 |
|
| 226 | #define genradix_ptr_alloc_inlined(_radix, _idx, _gfp) \
|
| 227 | (__genradix_cast(_radix) \
|
| 228 | (__genradix_ptr_inlined(&(_radix)->tree, \
|
| 229 | __genradix_idx_to_offset(_radix, _idx)) ?: \
|
| 230 | __genradix_ptr_alloc(&(_radix)->tree, \
|
| 231 | __genradix_idx_to_offset(_radix, _idx), \
|
| 232 | NULL, _gfp)))
|
| 233 |
|
| 234 | #define genradix_ptr_alloc_preallocated_inlined(_radix, _idx, _new_node, _gfp)\
|
| 235 | (__genradix_cast(_radix) \
|
| 236 | (__genradix_ptr_inlined(&(_radix)->tree, \
|
| 237 | __genradix_idx_to_offset(_radix, _idx)) ?: \
|
| 238 | __genradix_ptr_alloc(&(_radix)->tree, \
|
| 239 | __genradix_idx_to_offset(_radix, _idx), \
|
| 240 | _new_node, _gfp)))
|
| 241 |
|
| 242 | |
| 243 | * genradix_ptr_alloc - get a pointer to a genradix entry, allocating it
|
| 244 | * if necessary
|
| 245 | * @_radix: genradix to access
|
| 246 | * @_idx: index to fetch
|
| 247 | * @_gfp: gfp mask
|
| 248 | *
|
| 249 | * Returns a pointer to entry at @_idx, or NULL on allocation failure
|
| 250 |
|
| 251 | #define genradix_ptr_alloc(_radix, _idx, _gfp) \
|
| 252 | (__genradix_cast(_radix) \
|
| 253 | __genradix_ptr_alloc(&(_radix)->tree, \
|
| 254 | __genradix_idx_to_offset(_radix, _idx), \
|
| 255 | NULL, _gfp))
|
| 256 |
|
| 257 | #define genradix_ptr_alloc_preallocated(_radix, _idx, _new_node, _gfp)\
|
| 258 | (__genradix_cast(_radix) \
|
| 259 | __genradix_ptr_alloc(&(_radix)->tree, \
|
| 260 | __genradix_idx_to_offset(_radix, _idx), \
|
| 261 | _new_node, _gfp))
|
| 262 |
|
| 263 | struct genradix_iter {
|
| 264 | size_t offset;
|
| 265 | size_t pos;
|
| 266 | };
|
| 267 |
|
| 268 | |
| 269 | * genradix_iter_init - initialize a genradix_iter
|
| 270 | * @_radix: genradix that will be iterated over
|
| 271 | * @_idx: index to start iterating from
|
| 272 |
|
| 273 | #define genradix_iter_init(_radix, _idx) \
|
| 274 | ((struct genradix_iter) { \
|
| 275 | .pos = (_idx), \
|
| 276 | .offset = __genradix_idx_to_offset((_radix), (_idx)),\
|
| 277 | })
|
| 278 |
|
| 279 | void *__genradix_iter_peek(struct genradix_iter *, struct __genradix *, size_t);
|
| 280 |
|
| 281 | |
| 282 | * genradix_iter_peek - get first entry at or above iterator's current
|
| 283 | * position
|
| 284 | * @_iter: a genradix_iter
|
| 285 | * @_radix: genradix being iterated over
|
| 286 | *
|
| 287 | * If no more entries exist at or above @_iter's current position, returns NULL
|
| 288 |
|
| 289 | #define genradix_iter_peek(_iter, _radix) \
|
| 290 | (__genradix_cast(_radix) \
|
| 291 | __genradix_iter_peek(_iter, &(_radix)->tree, \
|
| 292 | __genradix_objs_per_page(_radix)))
|
| 293 |
|
| 294 | void *__genradix_iter_peek_prev(struct genradix_iter *, struct __genradix *,
|
| 295 | size_t, size_t);
|
| 296 |
|
| 297 | |
| 298 | * genradix_iter_peek_prev - get first entry at or below iterator's current
|
| 299 | * position
|
| 300 | * @_iter: a genradix_iter
|
| 301 | * @_radix: genradix being iterated over
|
| 302 | *
|
| 303 | * If no more entries exist at or below @_iter's current position, returns NULL
|
| 304 |
|
| 305 | #define genradix_iter_peek_prev(_iter, _radix) \
|
| 306 | (__genradix_cast(_radix) \
|
| 307 | __genradix_iter_peek_prev(_iter, &(_radix)->tree, \
|
| 308 | __genradix_objs_per_page(_radix), \
|
| 309 | __genradix_obj_size(_radix) + \
|
| 310 | __genradix_page_remainder(_radix)))
|
| 311 |
|
| 312 | static inline void __genradix_iter_advance(struct genradix_iter *iter,
|
| 313 | size_t obj_size)
|
| 314 | {
|
| 315 | if (iter->offset + obj_size < iter->offset) {
|
| 316 | iter->offset = SIZE_MAX;
|
| 317 | iter->pos = SIZE_MAX;
|
| 318 | return;
|
| 319 | }
|
| 320 |
|
| 321 | iter->offset += obj_size;
|
| 322 |
|
| 323 | if (!is_power_of_2(obj_size) &&
|
| 324 | (iter->offset & (GENRADIX_NODE_SIZE - 1)) + obj_size > GENRADIX_NODE_SIZE)
|
| 325 | iter->offset = round_up(iter->offset, GENRADIX_NODE_SIZE);
|
| 326 |
|
| 327 | iter->pos++;
|
| 328 | }
|
| 329 |
|
| 330 | #define genradix_iter_advance(_iter, _radix) \
|
| 331 | __genradix_iter_advance(_iter, __genradix_obj_size(_radix))
|
| 332 |
|
| 333 | static inline void __genradix_iter_rewind(struct genradix_iter *iter,
|
| 334 | size_t obj_size)
|
| 335 | {
|
| 336 | if (iter->offset == 0 ||
|
| 337 | iter->offset == SIZE_MAX) {
|
| 338 | iter->offset = SIZE_MAX;
|
| 339 | return;
|
| 340 | }
|
| 341 |
|
| 342 | if ((iter->offset & (GENRADIX_NODE_SIZE - 1)) == 0)
|
| 343 | iter->offset -= GENRADIX_NODE_SIZE % obj_size;
|
| 344 |
|
| 345 | iter->offset -= obj_size;
|
| 346 | iter->pos--;
|
| 347 | }
|
| 348 |
|
| 349 | #define genradix_iter_rewind(_iter, _radix) \
|
| 350 | __genradix_iter_rewind(_iter, __genradix_obj_size(_radix))
|
| 351 |
|
| 352 | #define genradix_for_each_from(_radix, _iter, _p, _start) \
|
| 353 | for (_iter = genradix_iter_init(_radix, _start); \
|
| 354 | (_p = genradix_iter_peek(&_iter, _radix)) != NULL; \
|
| 355 | genradix_iter_advance(&_iter, _radix))
|
| 356 |
|
| 357 | |
| 358 | * genradix_for_each - iterate over entry in a genradix
|
| 359 | * @_radix: genradix to iterate over
|
| 360 | * @_iter: a genradix_iter to track current position
|
| 361 | * @_p: pointer to genradix entry type
|
| 362 | *
|
| 363 | * On every iteration, @_p will point to the current entry, and @_iter.pos
|
| 364 | * will be the current entry's index.
|
| 365 |
|
| 366 | #define genradix_for_each(_radix, _iter, _p) \
|
| 367 | genradix_for_each_from(_radix, _iter, _p, 0)
|
| 368 |
|
| 369 | #define genradix_last_pos(_radix) \
|
| 370 | (SIZE_MAX / GENRADIX_NODE_SIZE * __genradix_objs_per_page(_radix) - 1)
|
| 371 |
|
| 372 | |
| 373 | * genradix_for_each_reverse - iterate over entry in a genradix, reverse order
|
| 374 | * @_radix: genradix to iterate over
|
| 375 | * @_iter: a genradix_iter to track current position
|
| 376 | * @_p: pointer to genradix entry type
|
| 377 | *
|
| 378 | * On every iteration, @_p will point to the current entry, and @_iter.pos
|
| 379 | * will be the current entry's index.
|
| 380 |
|
| 381 | #define genradix_for_each_reverse(_radix, _iter, _p) \
|
| 382 | for (_iter = genradix_iter_init(_radix, genradix_last_pos(_radix));\
|
| 383 | (_p = genradix_iter_peek_prev(&_iter, _radix)) != NULL;\
|
| 384 | genradix_iter_rewind(&_iter, _radix))
|
| 385 |
|
| 386 | int __genradix_prealloc(struct __genradix *, size_t, gfp_t);
|
| 387 |
|
| 388 | |
| 389 | * genradix_prealloc - preallocate entries in a generic radix tree
|
| 390 | * @_radix: genradix to preallocate
|
| 391 | * @_nr: number of entries to preallocate
|
| 392 | * @_gfp: gfp mask
|
| 393 | *
|
| 394 | * Returns 0 on success, -ENOMEM on failure
|
| 395 |
|
| 396 | #define genradix_prealloc(_radix, _nr, _gfp) \
|
| 397 | __genradix_prealloc(&(_radix)->tree, \
|
| 398 | __genradix_idx_to_offset(_radix, _nr + 1),\
|
| 399 | _gfp)
|
| 400 |
|
| 401 |
|
| 402 | #endif
|