1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 #ifndef _LINUX_MAPLE_TREE_H 3 #define _LINUX_MAPLE_TREE_H 4 /* 5 * Maple Tree - An RCU-safe adaptive tree for storing ranges 6 * Copyright (c) 2018-2022 Oracle 7 * Authors: Liam R. Howlett <Liam.Howlett@Oracle.com> 8 * Matthew Wilcox <willy@infradead.org> 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/rcupdate.h> 13 #include <linux/spinlock.h> 14 /* #define CONFIG_MAPLE_RCU_DISABLED */ 15 /* #define CONFIG_DEBUG_MAPLE_TREE_VERBOSE */ 16 17 /* 18 * Allocated nodes are mutable until they have been inserted into the tree, 19 * at which time they cannot change their type until they have been removed 20 * from the tree and an RCU grace period has passed. 21 * 22 * Removed nodes have their ->parent set to point to themselves. RCU readers 23 * check ->parent before relying on the value that they loaded from the 24 * slots array. This lets us reuse the slots array for the RCU head. 25 * 26 * Nodes in the tree point to their parent unless bit 0 is set. 27 */ 28 #if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) 29 /* 64bit sizes */ 30 #define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */ 31 #define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */ 32 #define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */ 33 #define MAPLE_ARANGE64_META_MAX 15 /* Out of range for metadata */ 34 #define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1) 35 #else 36 /* 32bit sizes */ 37 #define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */ 38 #define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */ 39 #define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */ 40 #define MAPLE_ARANGE64_META_MAX 31 /* Out of range for metadata */ 41 #define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2) 42 #endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */ 43 44 #define MAPLE_NODE_MASK 255UL 45 46 /* 47 * The node->parent of the root node has bit 0 set and the rest of the pointer 48 * is a pointer to the tree itself. No more bits are available in this pointer 49 * (on m68k, the data structure may only be 2-byte aligned). 50 * 51 * Internal non-root nodes can only have maple_range_* nodes as parents. The 52 * parent pointer is 256B aligned like all other tree nodes. When storing a 32 53 * or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an 54 * extra bit to store the offset. This extra bit comes from a reuse of the last 55 * bit in the node type. This is possible by using bit 1 to indicate if bit 2 56 * is part of the type or the slot. 57 * 58 * Once the type is decided, the decision of an allocation range type or a range 59 * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE 60 * flag. 61 * 62 * Node types: 63 * 0x??1 = Root 64 * 0x?00 = 16 bit nodes 65 * 0x010 = 32 bit nodes 66 * 0x110 = 64 bit nodes 67 * 68 * Slot size and location in the parent pointer: 69 * type : slot location 70 * 0x??1 : Root 71 * 0x?00 : 16 bit values, type in 0-1, slot in 2-6 72 * 0x010 : 32 bit values, type in 0-2, slot in 3-6 73 * 0x110 : 64 bit values, type in 0-2, slot in 3-6 74 */ 75 76 /* 77 * This metadata is used to optimize the gap updating code and in reverse 78 * searching for gaps or any other code that needs to find the end of the data. 79 */ 80 struct maple_metadata { 81 unsigned char end; 82 unsigned char gap; 83 }; 84 85 /* 86 * Leaf nodes do not store pointers to nodes, they store user data. Users may 87 * store almost any bit pattern. As noted above, the optimisation of storing an 88 * entry at 0 in the root pointer cannot be done for data which have the bottom 89 * two bits set to '10'. We also reserve values with the bottom two bits set to 90 * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs 91 * return errnos as a negative errno shifted right by two bits and the bottom 92 * two bits set to '10', and while choosing to store these values in the array 93 * is not an error, it may lead to confusion if you're testing for an error with 94 * mas_is_err(). 95 * 96 * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits 97 * 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now. 98 * 99 * In regular B-Tree terms, pivots are called keys. The term pivot is used to 100 * indicate that the tree is specifying ranges, Pivots may appear in the 101 * subtree with an entry attached to the value whereas keys are unique to a 102 * specific position of a B-tree. Pivot values are inclusive of the slot with 103 * the same index. 104 */ 105 106 struct maple_range_64 { 107 struct maple_pnode *parent; 108 unsigned long pivot[MAPLE_RANGE64_SLOTS - 1]; 109 union { 110 void __rcu *slot[MAPLE_RANGE64_SLOTS]; 111 struct { 112 void __rcu *pad[MAPLE_RANGE64_SLOTS - 1]; 113 struct maple_metadata meta; 114 }; 115 }; 116 }; 117 118 /* 119 * At tree creation time, the user can specify that they're willing to trade off 120 * storing fewer entries in a tree in return for storing more information in 121 * each node. 122 * 123 * The maple tree supports recording the largest range of NULL entries available 124 * in this node, also called gaps. This optimises the tree for allocating a 125 * range. 126 */ 127 struct maple_arange_64 { 128 struct maple_pnode *parent; 129 unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1]; 130 void __rcu *slot[MAPLE_ARANGE64_SLOTS]; 131 unsigned long gap[MAPLE_ARANGE64_SLOTS]; 132 struct maple_metadata meta; 133 }; 134 135 struct maple_alloc { 136 unsigned long total; 137 unsigned char node_count; 138 unsigned int request_count; 139 struct maple_alloc *slot[MAPLE_ALLOC_SLOTS]; 140 }; 141 142 struct maple_topiary { 143 struct maple_pnode *parent; 144 struct maple_enode *next; /* Overlaps the pivot */ 145 }; 146 147 enum maple_type { 148 maple_dense, 149 maple_leaf_64, 150 maple_range_64, 151 maple_arange_64, 152 }; 153 154 155 /** 156 * DOC: Maple tree flags 157 * 158 * * MT_FLAGS_ALLOC_RANGE - Track gaps in this tree 159 * * MT_FLAGS_USE_RCU - Operate in RCU mode 160 * * MT_FLAGS_HEIGHT_OFFSET - The position of the tree height in the flags 161 * * MT_FLAGS_HEIGHT_MASK - The mask for the maple tree height value 162 * * MT_FLAGS_LOCK_MASK - How the mt_lock is used 163 * * MT_FLAGS_LOCK_IRQ - Acquired irq-safe 164 * * MT_FLAGS_LOCK_BH - Acquired bh-safe 165 * * MT_FLAGS_LOCK_EXTERN - mt_lock is not used 166 * 167 * MAPLE_HEIGHT_MAX The largest height that can be stored 168 */ 169 #define MT_FLAGS_ALLOC_RANGE 0x01 170 #define MT_FLAGS_USE_RCU 0x02 171 #define MT_FLAGS_HEIGHT_OFFSET 0x02 172 #define MT_FLAGS_HEIGHT_MASK 0x7C 173 #define MT_FLAGS_LOCK_MASK 0x300 174 #define MT_FLAGS_LOCK_IRQ 0x100 175 #define MT_FLAGS_LOCK_BH 0x200 176 #define MT_FLAGS_LOCK_EXTERN 0x300 177 178 #define MAPLE_HEIGHT_MAX 31 179 180 181 #define MAPLE_NODE_TYPE_MASK 0x0F 182 #define MAPLE_NODE_TYPE_SHIFT 0x03 183 184 #define MAPLE_RESERVED_RANGE 4096 185 186 #ifdef CONFIG_LOCKDEP 187 typedef struct lockdep_map *lockdep_map_p; 188 #define mt_lock_is_held(mt) lock_is_held(mt->ma_external_lock) 189 #define mt_set_external_lock(mt, lock) \ 190 (mt)->ma_external_lock = &(lock)->dep_map 191 #else 192 typedef struct { /* nothing */ } lockdep_map_p; 193 #define mt_lock_is_held(mt) 1 194 #define mt_set_external_lock(mt, lock) do { } while (0) 195 #endif 196 197 /* 198 * If the tree contains a single entry at index 0, it is usually stored in 199 * tree->ma_root. To optimise for the page cache, an entry which ends in '00', 200 * '01' or '11' is stored in the root, but an entry which ends in '10' will be 201 * stored in a node. Bits 3-6 are used to store enum maple_type. 202 * 203 * The flags are used both to store some immutable information about this tree 204 * (set at tree creation time) and dynamic information set under the spinlock. 205 * 206 * Another use of flags are to indicate global states of the tree. This is the 207 * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in 208 * RCU mode. This mode was added to allow the tree to reuse nodes instead of 209 * re-allocating and RCU freeing nodes when there is a single user. 210 */ 211 struct maple_tree { 212 union { 213 spinlock_t ma_lock; 214 lockdep_map_p ma_external_lock; 215 }; 216 void __rcu *ma_root; 217 unsigned int ma_flags; 218 }; 219 220 /** 221 * MTREE_INIT() - Initialize a maple tree 222 * @name: The maple tree name 223 * @__flags: The maple tree flags 224 * 225 */ 226 #define MTREE_INIT(name, __flags) { \ 227 .ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock), \ 228 .ma_flags = __flags, \ 229 .ma_root = NULL, \ 230 } 231 232 /** 233 * MTREE_INIT_EXT() - Initialize a maple tree with an external lock. 234 * @name: The tree name 235 * @__flags: The maple tree flags 236 * @__lock: The external lock 237 */ 238 #ifdef CONFIG_LOCKDEP 239 #define MTREE_INIT_EXT(name, __flags, __lock) { \ 240 .ma_external_lock = &(__lock).dep_map, \ 241 .ma_flags = (__flags), \ 242 .ma_root = NULL, \ 243 } 244 #else 245 #define MTREE_INIT_EXT(name, __flags, __lock) MTREE_INIT(name, __flags) 246 #endif 247 248 #define DEFINE_MTREE(name) \ 249 struct maple_tree name = MTREE_INIT(name, 0) 250 251 #define mtree_lock(mt) spin_lock((&(mt)->ma_lock)) 252 #define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock)) 253 254 /* 255 * The Maple Tree squeezes various bits in at various points which aren't 256 * necessarily obvious. Usually, this is done by observing that pointers are 257 * N-byte aligned and thus the bottom log_2(N) bits are available for use. We 258 * don't use the high bits of pointers to store additional information because 259 * we don't know what bits are unused on any given architecture. 260 * 261 * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8 262 * low bits for our own purposes. Nodes are currently of 4 types: 263 * 1. Single pointer (Range is 0-0) 264 * 2. Non-leaf Allocation Range nodes 265 * 3. Non-leaf Range nodes 266 * 4. Leaf Range nodes All nodes consist of a number of node slots, 267 * pivots, and a parent pointer. 268 */ 269 270 struct maple_node { 271 union { 272 struct { 273 struct maple_pnode *parent; 274 void __rcu *slot[MAPLE_NODE_SLOTS]; 275 }; 276 struct { 277 void *pad; 278 struct rcu_head rcu; 279 struct maple_enode *piv_parent; 280 unsigned char parent_slot; 281 enum maple_type type; 282 unsigned char slot_len; 283 unsigned int ma_flags; 284 }; 285 struct maple_range_64 mr64; 286 struct maple_arange_64 ma64; 287 struct maple_alloc alloc; 288 }; 289 }; 290 291 /* 292 * More complicated stores can cause two nodes to become one or three and 293 * potentially alter the height of the tree. Either half of the tree may need 294 * to be rebalanced against the other. The ma_topiary struct is used to track 295 * which nodes have been 'cut' from the tree so that the change can be done 296 * safely at a later date. This is done to support RCU. 297 */ 298 struct ma_topiary { 299 struct maple_enode *head; 300 struct maple_enode *tail; 301 struct maple_tree *mtree; 302 }; 303 304 void *mtree_load(struct maple_tree *mt, unsigned long index); 305 306 int mtree_insert(struct maple_tree *mt, unsigned long index, 307 void *entry, gfp_t gfp); 308 int mtree_insert_range(struct maple_tree *mt, unsigned long first, 309 unsigned long last, void *entry, gfp_t gfp); 310 int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, 311 void *entry, unsigned long size, unsigned long min, 312 unsigned long max, gfp_t gfp); 313 int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, 314 void *entry, unsigned long size, unsigned long min, 315 unsigned long max, gfp_t gfp); 316 317 int mtree_store_range(struct maple_tree *mt, unsigned long first, 318 unsigned long last, void *entry, gfp_t gfp); 319 int mtree_store(struct maple_tree *mt, unsigned long index, 320 void *entry, gfp_t gfp); 321 void *mtree_erase(struct maple_tree *mt, unsigned long index); 322 323 void mtree_destroy(struct maple_tree *mt); 324 void __mt_destroy(struct maple_tree *mt); 325 326 /** 327 * mtree_empty() - Determine if a tree has any present entries. 328 * @mt: Maple Tree. 329 * 330 * Context: Any context. 331 * Return: %true if the tree contains only NULL pointers. 332 */ 333 static inline bool mtree_empty(const struct maple_tree *mt) 334 { 335 return mt->ma_root == NULL; 336 } 337 338 /* Advanced API */ 339 340 /* 341 * The maple state is defined in the struct ma_state and is used to keep track 342 * of information during operations, and even between operations when using the 343 * advanced API. 344 * 345 * If state->node has bit 0 set then it references a tree location which is not 346 * a node (eg the root). If bit 1 is set, the rest of the bits are a negative 347 * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the 348 * node type. 349 * 350 * state->alloc either has a request number of nodes or an allocated node. If 351 * stat->alloc has a requested number of nodes, the first bit will be set (0x1) 352 * and the remaining bits are the value. If state->alloc is a node, then the 353 * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for 354 * storing more allocated nodes, a total number of nodes allocated, and the 355 * node_count in this node. node_count is the number of allocated nodes in this 356 * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further 357 * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc 358 * by removing a node from the state->alloc node until state->alloc->node_count 359 * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted 360 * to state->alloc. Nodes are pushed onto state->alloc by putting the current 361 * state->alloc into the pushed node's slot[0]. 362 * 363 * The state also contains the implied min/max of the state->node, the depth of 364 * this search, and the offset. The implied min/max are either from the parent 365 * node or are 0-oo for the root node. The depth is incremented or decremented 366 * every time a node is walked down or up. The offset is the slot/pivot of 367 * interest in the node - either for reading or writing. 368 * 369 * When returning a value the maple state index and last respectively contain 370 * the start and end of the range for the entry. Ranges are inclusive in the 371 * Maple Tree. 372 */ 373 struct ma_state { 374 struct maple_tree *tree; /* The tree we're operating in */ 375 unsigned long index; /* The index we're operating on - range start */ 376 unsigned long last; /* The last index we're operating on - range end */ 377 struct maple_enode *node; /* The node containing this entry */ 378 unsigned long min; /* The minimum index of this node - implied pivot min */ 379 unsigned long max; /* The maximum index of this node - implied pivot max */ 380 struct maple_alloc *alloc; /* Allocated nodes for this operation */ 381 unsigned char depth; /* depth of tree descent during write */ 382 unsigned char offset; 383 unsigned char mas_flags; 384 }; 385 386 struct ma_wr_state { 387 struct ma_state *mas; 388 struct maple_node *node; /* Decoded mas->node */ 389 unsigned long r_min; /* range min */ 390 unsigned long r_max; /* range max */ 391 enum maple_type type; /* mas->node type */ 392 unsigned char offset_end; /* The offset where the write ends */ 393 unsigned char node_end; /* mas->node end */ 394 unsigned long *pivots; /* mas->node->pivots pointer */ 395 unsigned long end_piv; /* The pivot at the offset end */ 396 void __rcu **slots; /* mas->node->slots pointer */ 397 void *entry; /* The entry to write */ 398 void *content; /* The existing entry that is being overwritten */ 399 }; 400 401 #define mas_lock(mas) spin_lock(&((mas)->tree->ma_lock)) 402 #define mas_unlock(mas) spin_unlock(&((mas)->tree->ma_lock)) 403 404 405 /* 406 * Special values for ma_state.node. 407 * MAS_START means we have not searched the tree. 408 * MAS_ROOT means we have searched the tree and the entry we found lives in 409 * the root of the tree (ie it has index 0, length 1 and is the only entry in 410 * the tree). 411 * MAS_NONE means we have searched the tree and there is no node in the 412 * tree for this entry. For example, we searched for index 1 in an empty 413 * tree. Or we have a tree which points to a full leaf node and we 414 * searched for an entry which is larger than can be contained in that 415 * leaf node. 416 * MA_ERROR represents an errno. After dropping the lock and attempting 417 * to resolve the error, the walk would have to be restarted from the 418 * top of the tree as the tree may have been modified. 419 */ 420 #define MAS_START ((struct maple_enode *)1UL) 421 #define MAS_ROOT ((struct maple_enode *)5UL) 422 #define MAS_NONE ((struct maple_enode *)9UL) 423 #define MAS_PAUSE ((struct maple_enode *)17UL) 424 #define MA_ERROR(err) \ 425 ((struct maple_enode *)(((unsigned long)err << 2) | 2UL)) 426 427 #define MA_STATE(name, mt, first, end) \ 428 struct ma_state name = { \ 429 .tree = mt, \ 430 .index = first, \ 431 .last = end, \ 432 .node = MAS_START, \ 433 .min = 0, \ 434 .max = ULONG_MAX, \ 435 .alloc = NULL, \ 436 } 437 438 #define MA_WR_STATE(name, ma_state, wr_entry) \ 439 struct ma_wr_state name = { \ 440 .mas = ma_state, \ 441 .content = NULL, \ 442 .entry = wr_entry, \ 443 } 444 445 #define MA_TOPIARY(name, tree) \ 446 struct ma_topiary name = { \ 447 .head = NULL, \ 448 .tail = NULL, \ 449 .mtree = tree, \ 450 } 451 452 void *mas_walk(struct ma_state *mas); 453 void *mas_store(struct ma_state *mas, void *entry); 454 void *mas_erase(struct ma_state *mas); 455 int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp); 456 void mas_store_prealloc(struct ma_state *mas, void *entry); 457 void *mas_find(struct ma_state *mas, unsigned long max); 458 void *mas_find_rev(struct ma_state *mas, unsigned long min); 459 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp); 460 bool mas_is_err(struct ma_state *mas); 461 462 bool mas_nomem(struct ma_state *mas, gfp_t gfp); 463 void mas_pause(struct ma_state *mas); 464 void maple_tree_init(void); 465 void mas_destroy(struct ma_state *mas); 466 int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries); 467 468 void *mas_prev(struct ma_state *mas, unsigned long min); 469 void *mas_next(struct ma_state *mas, unsigned long max); 470 471 int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max, 472 unsigned long size); 473 474 /* Checks if a mas has not found anything */ 475 static inline bool mas_is_none(struct ma_state *mas) 476 { 477 return mas->node == MAS_NONE; 478 } 479 480 /* Checks if a mas has been paused */ 481 static inline bool mas_is_paused(struct ma_state *mas) 482 { 483 return mas->node == MAS_PAUSE; 484 } 485 486 void mas_dup_tree(struct ma_state *oldmas, struct ma_state *mas); 487 void mas_dup_store(struct ma_state *mas, void *entry); 488 489 /* 490 * This finds an empty area from the highest address to the lowest. 491 * AKA "Topdown" version, 492 */ 493 int mas_empty_area_rev(struct ma_state *mas, unsigned long min, 494 unsigned long max, unsigned long size); 495 /** 496 * mas_reset() - Reset a Maple Tree operation state. 497 * @mas: Maple Tree operation state. 498 * 499 * Resets the error or walk state of the @mas so future walks of the 500 * array will start from the root. Use this if you have dropped the 501 * lock and want to reuse the ma_state. 502 * 503 * Context: Any context. 504 */ 505 static inline void mas_reset(struct ma_state *mas) 506 { 507 mas->node = MAS_START; 508 } 509 510 /** 511 * mas_for_each() - Iterate over a range of the maple tree. 512 * @__mas: Maple Tree operation state (maple_state) 513 * @__entry: Entry retrieved from the tree 514 * @__max: maximum index to retrieve from the tree 515 * 516 * When returned, mas->index and mas->last will hold the entire range for the 517 * entry. 518 * 519 * Note: may return the zero entry. 520 * 521 */ 522 #define mas_for_each(__mas, __entry, __max) \ 523 while (((__entry) = mas_find((__mas), (__max))) != NULL) 524 525 526 /** 527 * mas_set_range() - Set up Maple Tree operation state for a different index. 528 * @mas: Maple Tree operation state. 529 * @start: New start of range in the Maple Tree. 530 * @last: New end of range in the Maple Tree. 531 * 532 * Move the operation state to refer to a different range. This will 533 * have the effect of starting a walk from the top; see mas_next() 534 * to move to an adjacent index. 535 */ 536 static inline 537 void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last) 538 { 539 mas->index = start; 540 mas->last = last; 541 mas->node = MAS_START; 542 } 543 544 /** 545 * mas_set() - Set up Maple Tree operation state for a different index. 546 * @mas: Maple Tree operation state. 547 * @index: New index into the Maple Tree. 548 * 549 * Move the operation state to refer to a different index. This will 550 * have the effect of starting a walk from the top; see mas_next() 551 * to move to an adjacent index. 552 */ 553 static inline void mas_set(struct ma_state *mas, unsigned long index) 554 { 555 556 mas_set_range(mas, index, index); 557 } 558 559 static inline bool mt_external_lock(const struct maple_tree *mt) 560 { 561 return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN; 562 } 563 564 /** 565 * mt_init_flags() - Initialise an empty maple tree with flags. 566 * @mt: Maple Tree 567 * @flags: maple tree flags. 568 * 569 * If you need to initialise a Maple Tree with special flags (eg, an 570 * allocation tree), use this function. 571 * 572 * Context: Any context. 573 */ 574 static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags) 575 { 576 mt->ma_flags = flags; 577 if (!mt_external_lock(mt)) 578 spin_lock_init(&mt->ma_lock); 579 rcu_assign_pointer(mt->ma_root, NULL); 580 } 581 582 /** 583 * mt_init() - Initialise an empty maple tree. 584 * @mt: Maple Tree 585 * 586 * An empty Maple Tree. 587 * 588 * Context: Any context. 589 */ 590 static inline void mt_init(struct maple_tree *mt) 591 { 592 mt_init_flags(mt, 0); 593 } 594 595 static inline bool mt_in_rcu(struct maple_tree *mt) 596 { 597 #ifdef CONFIG_MAPLE_RCU_DISABLED 598 return false; 599 #endif 600 return mt->ma_flags & MT_FLAGS_USE_RCU; 601 } 602 603 /** 604 * mt_clear_in_rcu() - Switch the tree to non-RCU mode. 605 * @mt: The Maple Tree 606 */ 607 static inline void mt_clear_in_rcu(struct maple_tree *mt) 608 { 609 if (!mt_in_rcu(mt)) 610 return; 611 612 if (mt_external_lock(mt)) { 613 BUG_ON(!mt_lock_is_held(mt)); 614 mt->ma_flags &= ~MT_FLAGS_USE_RCU; 615 } else { 616 mtree_lock(mt); 617 mt->ma_flags &= ~MT_FLAGS_USE_RCU; 618 mtree_unlock(mt); 619 } 620 } 621 622 /** 623 * mt_set_in_rcu() - Switch the tree to RCU safe mode. 624 * @mt: The Maple Tree 625 */ 626 static inline void mt_set_in_rcu(struct maple_tree *mt) 627 { 628 if (mt_in_rcu(mt)) 629 return; 630 631 if (mt_external_lock(mt)) { 632 BUG_ON(!mt_lock_is_held(mt)); 633 mt->ma_flags |= MT_FLAGS_USE_RCU; 634 } else { 635 mtree_lock(mt); 636 mt->ma_flags |= MT_FLAGS_USE_RCU; 637 mtree_unlock(mt); 638 } 639 } 640 641 static inline unsigned int mt_height(const struct maple_tree *mt) 642 643 { 644 return (mt->ma_flags & MT_FLAGS_HEIGHT_MASK) >> MT_FLAGS_HEIGHT_OFFSET; 645 } 646 647 void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max); 648 void *mt_find_after(struct maple_tree *mt, unsigned long *index, 649 unsigned long max); 650 void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min); 651 void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max); 652 653 /** 654 * mt_for_each - Iterate over each entry starting at index until max. 655 * @__tree: The Maple Tree 656 * @__entry: The current entry 657 * @__index: The index to update to track the location in the tree 658 * @__max: The maximum limit for @index 659 * 660 * Note: Will not return the zero entry. 661 */ 662 #define mt_for_each(__tree, __entry, __index, __max) \ 663 for (__entry = mt_find(__tree, &(__index), __max); \ 664 __entry; __entry = mt_find_after(__tree, &(__index), __max)) 665 666 667 #ifdef CONFIG_DEBUG_MAPLE_TREE 668 extern atomic_t maple_tree_tests_run; 669 extern atomic_t maple_tree_tests_passed; 670 671 void mt_dump(const struct maple_tree *mt); 672 void mt_validate(struct maple_tree *mt); 673 void mt_cache_shrink(void); 674 #define MT_BUG_ON(__tree, __x) do { \ 675 atomic_inc(&maple_tree_tests_run); \ 676 if (__x) { \ 677 pr_info("BUG at %s:%d (%u)\n", \ 678 __func__, __LINE__, __x); \ 679 mt_dump(__tree); \ 680 pr_info("Pass: %u Run:%u\n", \ 681 atomic_read(&maple_tree_tests_passed), \ 682 atomic_read(&maple_tree_tests_run)); \ 683 dump_stack(); \ 684 } else { \ 685 atomic_inc(&maple_tree_tests_passed); \ 686 } \ 687 } while (0) 688 #else 689 #define MT_BUG_ON(__tree, __x) BUG_ON(__x) 690 #endif /* CONFIG_DEBUG_MAPLE_TREE */ 691 692 #endif /*_LINUX_MAPLE_TREE_H */ 693