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
16 /*
17 * Allocated nodes are mutable until they have been inserted into the tree,
18 * at which time they cannot change their type until they have been removed
19 * from the tree and an RCU grace period has passed.
20 *
21 * Removed nodes have their ->parent set to point to themselves. RCU readers
22 * check ->parent before relying on the value that they loaded from the
23 * slots array. This lets us reuse the slots array for the RCU head.
24 *
25 * Nodes in the tree point to their parent unless bit 0 is set.
26 */
27 #if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
28 /* 64bit sizes */
29 #define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */
30 #define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */
31 #define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */
32 #define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1)
33 #else
34 /* 32bit sizes */
35 #define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */
36 #define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */
37 #define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */
38 #define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2)
39 #endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */
40
41 #define MAPLE_NODE_MASK 255UL
42
43 /*
44 * The node->parent of the root node has bit 0 set and the rest of the pointer
45 * is a pointer to the tree itself. No more bits are available in this pointer
46 * (on m68k, the data structure may only be 2-byte aligned).
47 *
48 * Internal non-root nodes can only have maple_range_* nodes as parents. The
49 * parent pointer is 256B aligned like all other tree nodes. When storing a 32
50 * or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an
51 * extra bit to store the offset. This extra bit comes from a reuse of the last
52 * bit in the node type. This is possible by using bit 1 to indicate if bit 2
53 * is part of the type or the slot.
54 *
55 * Once the type is decided, the decision of an allocation range type or a range
56 * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
57 * flag.
58 *
59 * Node types:
60 * 0x??1 = Root
61 * 0x?00 = 16 bit nodes
62 * 0x010 = 32 bit nodes
63 * 0x110 = 64 bit nodes
64 *
65 * Slot size and location in the parent pointer:
66 * type : slot location
67 * 0x??1 : Root
68 * 0x?00 : 16 bit values, type in 0-1, slot in 2-6
69 * 0x010 : 32 bit values, type in 0-2, slot in 3-6
70 * 0x110 : 64 bit values, type in 0-2, slot in 3-6
71 */
72
73 /*
74 * This metadata is used to optimize the gap updating code and in reverse
75 * searching for gaps or any other code that needs to find the end of the data.
76 */
77 struct maple_metadata {
78 unsigned char end;
79 unsigned char gap;
80 };
81
82 /*
83 * Leaf nodes do not store pointers to nodes, they store user data. Users may
84 * store almost any bit pattern. As noted above, the optimisation of storing an
85 * entry at 0 in the root pointer cannot be done for data which have the bottom
86 * two bits set to '10'. We also reserve values with the bottom two bits set to
87 * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs
88 * return errnos as a negative errno shifted right by two bits and the bottom
89 * two bits set to '10', and while choosing to store these values in the array
90 * is not an error, it may lead to confusion if you're testing for an error with
91 * mas_is_err().
92 *
93 * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits
94 * 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now.
95 *
96 * In regular B-Tree terms, pivots are called keys. The term pivot is used to
97 * indicate that the tree is specifying ranges, Pivots may appear in the
98 * subtree with an entry attached to the value whereas keys are unique to a
99 * specific position of a B-tree. Pivot values are inclusive of the slot with
100 * the same index.
101 */
102
103 struct maple_range_64 {
104 struct maple_pnode *parent;
105 unsigned long pivot[MAPLE_RANGE64_SLOTS - 1];
106 union {
107 void __rcu *slot[MAPLE_RANGE64_SLOTS];
108 struct {
109 void __rcu *pad[MAPLE_RANGE64_SLOTS - 1];
110 struct maple_metadata meta;
111 };
112 };
113 };
114
115 /*
116 * At tree creation time, the user can specify that they're willing to trade off
117 * storing fewer entries in a tree in return for storing more information in
118 * each node.
119 *
120 * The maple tree supports recording the largest range of NULL entries available
121 * in this node, also called gaps. This optimises the tree for allocating a
122 * range.
123 */
124 struct maple_arange_64 {
125 struct maple_pnode *parent;
126 unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1];
127 void __rcu *slot[MAPLE_ARANGE64_SLOTS];
128 unsigned long gap[MAPLE_ARANGE64_SLOTS];
129 struct maple_metadata meta;
130 };
131
132 struct maple_alloc {
133 unsigned long total;
134 unsigned char node_count;
135 unsigned int request_count;
136 struct maple_alloc *slot[MAPLE_ALLOC_SLOTS];
137 };
138
139 struct maple_topiary {
140 struct maple_pnode *parent;
141 struct maple_enode *next; /* Overlaps the pivot */
142 };
143
144 enum maple_type {
145 maple_dense,
146 maple_leaf_64,
147 maple_range_64,
148 maple_arange_64,
149 };
150
151
152 /**
153 * DOC: Maple tree flags
154 *
155 * * MT_FLAGS_ALLOC_RANGE - Track gaps in this tree
156 * * MT_FLAGS_USE_RCU - Operate in RCU mode
157 * * MT_FLAGS_HEIGHT_OFFSET - The position of the tree height in the flags
158 * * MT_FLAGS_HEIGHT_MASK - The mask for the maple tree height value
159 * * MT_FLAGS_LOCK_MASK - How the mt_lock is used
160 * * MT_FLAGS_LOCK_IRQ - Acquired irq-safe
161 * * MT_FLAGS_LOCK_BH - Acquired bh-safe
162 * * MT_FLAGS_LOCK_EXTERN - mt_lock is not used
163 *
164 * MAPLE_HEIGHT_MAX The largest height that can be stored
165 */
166 #define MT_FLAGS_ALLOC_RANGE 0x01
167 #define MT_FLAGS_USE_RCU 0x02
168 #define MT_FLAGS_HEIGHT_OFFSET 0x02
169 #define MT_FLAGS_HEIGHT_MASK 0x7C
170 #define MT_FLAGS_LOCK_MASK 0x300
171 #define MT_FLAGS_LOCK_IRQ 0x100
172 #define MT_FLAGS_LOCK_BH 0x200
173 #define MT_FLAGS_LOCK_EXTERN 0x300
174
175 #define MAPLE_HEIGHT_MAX 31
176
177
178 #define MAPLE_NODE_TYPE_MASK 0x0F
179 #define MAPLE_NODE_TYPE_SHIFT 0x03
180
181 #define MAPLE_RESERVED_RANGE 4096
182
183 #ifdef CONFIG_LOCKDEP
184 typedef struct lockdep_map *lockdep_map_p;
185 #define mt_lock_is_held(mt) \
186 (!(mt)->ma_external_lock || lock_is_held((mt)->ma_external_lock))
187
188 #define mt_write_lock_is_held(mt) \
189 (!(mt)->ma_external_lock || \
190 lock_is_held_type((mt)->ma_external_lock, 0))
191
192 #define mt_set_external_lock(mt, lock) \
193 (mt)->ma_external_lock = &(lock)->dep_map
194
195 #define mt_on_stack(mt) (mt).ma_external_lock = NULL
196 #else
197 typedef struct { /* nothing */ } lockdep_map_p;
198 #define mt_lock_is_held(mt) 1
199 #define mt_write_lock_is_held(mt) 1
200 #define mt_set_external_lock(mt, lock) do { } while (0)
201 #define mt_on_stack(mt) do { } while (0)
202 #endif
203
204 /*
205 * If the tree contains a single entry at index 0, it is usually stored in
206 * tree->ma_root. To optimise for the page cache, an entry which ends in '00',
207 * '01' or '11' is stored in the root, but an entry which ends in '10' will be
208 * stored in a node. Bits 3-6 are used to store enum maple_type.
209 *
210 * The flags are used both to store some immutable information about this tree
211 * (set at tree creation time) and dynamic information set under the spinlock.
212 *
213 * Another use of flags are to indicate global states of the tree. This is the
214 * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in
215 * RCU mode. This mode was added to allow the tree to reuse nodes instead of
216 * re-allocating and RCU freeing nodes when there is a single user.
217 */
218 struct maple_tree {
219 union {
220 spinlock_t ma_lock;
221 lockdep_map_p ma_external_lock;
222 };
223 unsigned int ma_flags;
224 void __rcu *ma_root;
225 };
226
227 /**
228 * MTREE_INIT() - Initialize a maple tree
229 * @name: The maple tree name
230 * @__flags: The maple tree flags
231 *
232 */
233 #define MTREE_INIT(name, __flags) { \
234 .ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock), \
235 .ma_flags = __flags, \
236 .ma_root = NULL, \
237 }
238
239 /**
240 * MTREE_INIT_EXT() - Initialize a maple tree with an external lock.
241 * @name: The tree name
242 * @__flags: The maple tree flags
243 * @__lock: The external lock
244 */
245 #ifdef CONFIG_LOCKDEP
246 #define MTREE_INIT_EXT(name, __flags, __lock) { \
247 .ma_external_lock = &(__lock).dep_map, \
248 .ma_flags = (__flags), \
249 .ma_root = NULL, \
250 }
251 #else
252 #define MTREE_INIT_EXT(name, __flags, __lock) MTREE_INIT(name, __flags)
253 #endif
254
255 #define DEFINE_MTREE(name) \
256 struct maple_tree name = MTREE_INIT(name, 0)
257
258 #define mtree_lock(mt) spin_lock((&(mt)->ma_lock))
259 #define mtree_lock_nested(mas, subclass) \
260 spin_lock_nested((&(mt)->ma_lock), subclass)
261 #define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock))
262
263 /*
264 * The Maple Tree squeezes various bits in at various points which aren't
265 * necessarily obvious. Usually, this is done by observing that pointers are
266 * N-byte aligned and thus the bottom log_2(N) bits are available for use. We
267 * don't use the high bits of pointers to store additional information because
268 * we don't know what bits are unused on any given architecture.
269 *
270 * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
271 * low bits for our own purposes. Nodes are currently of 4 types:
272 * 1. Single pointer (Range is 0-0)
273 * 2. Non-leaf Allocation Range nodes
274 * 3. Non-leaf Range nodes
275 * 4. Leaf Range nodes All nodes consist of a number of node slots,
276 * pivots, and a parent pointer.
277 */
278
279 struct maple_node {
280 union {
281 struct {
282 struct maple_pnode *parent;
283 void __rcu *slot[MAPLE_NODE_SLOTS];
284 };
285 struct {
286 void *pad;
287 struct rcu_head rcu;
288 struct maple_enode *piv_parent;
289 unsigned char parent_slot;
290 enum maple_type type;
291 unsigned char slot_len;
292 unsigned int ma_flags;
293 };
294 struct maple_range_64 mr64;
295 struct maple_arange_64 ma64;
296 struct maple_alloc alloc;
297 };
298 };
299
300 /*
301 * More complicated stores can cause two nodes to become one or three and
302 * potentially alter the height of the tree. Either half of the tree may need
303 * to be rebalanced against the other. The ma_topiary struct is used to track
304 * which nodes have been 'cut' from the tree so that the change can be done
305 * safely at a later date. This is done to support RCU.
306 */
307 struct ma_topiary {
308 struct maple_enode *head;
309 struct maple_enode *tail;
310 struct maple_tree *mtree;
311 };
312
313 void *mtree_load(struct maple_tree *mt, unsigned long index);
314
315 int mtree_insert(struct maple_tree *mt, unsigned long index,
316 void *entry, gfp_t gfp);
317 int mtree_insert_range(struct maple_tree *mt, unsigned long first,
318 unsigned long last, void *entry, gfp_t gfp);
319 int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
320 void *entry, unsigned long size, unsigned long min,
321 unsigned long max, gfp_t gfp);
322 int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
323 void *entry, unsigned long size, unsigned long min,
324 unsigned long max, gfp_t gfp);
325
326 int mtree_store_range(struct maple_tree *mt, unsigned long first,
327 unsigned long last, void *entry, gfp_t gfp);
328 int mtree_store(struct maple_tree *mt, unsigned long index,
329 void *entry, gfp_t gfp);
330 void *mtree_erase(struct maple_tree *mt, unsigned long index);
331
332 int mtree_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp);
333 int __mt_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp);
334
335 void mtree_destroy(struct maple_tree *mt);
336 void __mt_destroy(struct maple_tree *mt);
337
338 /**
339 * mtree_empty() - Determine if a tree has any present entries.
340 * @mt: Maple Tree.
341 *
342 * Context: Any context.
343 * Return: %true if the tree contains only NULL pointers.
344 */
mtree_empty(const struct maple_tree * mt)345 static inline bool mtree_empty(const struct maple_tree *mt)
346 {
347 return mt->ma_root == NULL;
348 }
349
350 /* Advanced API */
351
352 /*
353 * The maple state is defined in the struct ma_state and is used to keep track
354 * of information during operations, and even between operations when using the
355 * advanced API.
356 *
357 * If state->node has bit 0 set then it references a tree location which is not
358 * a node (eg the root). If bit 1 is set, the rest of the bits are a negative
359 * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the
360 * node type.
361 *
362 * state->alloc either has a request number of nodes or an allocated node. If
363 * stat->alloc has a requested number of nodes, the first bit will be set (0x1)
364 * and the remaining bits are the value. If state->alloc is a node, then the
365 * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for
366 * storing more allocated nodes, a total number of nodes allocated, and the
367 * node_count in this node. node_count is the number of allocated nodes in this
368 * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
369 * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc
370 * by removing a node from the state->alloc node until state->alloc->node_count
371 * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
372 * to state->alloc. Nodes are pushed onto state->alloc by putting the current
373 * state->alloc into the pushed node's slot[0].
374 *
375 * The state also contains the implied min/max of the state->node, the depth of
376 * this search, and the offset. The implied min/max are either from the parent
377 * node or are 0-oo for the root node. The depth is incremented or decremented
378 * every time a node is walked down or up. The offset is the slot/pivot of
379 * interest in the node - either for reading or writing.
380 *
381 * When returning a value the maple state index and last respectively contain
382 * the start and end of the range for the entry. Ranges are inclusive in the
383 * Maple Tree.
384 */
385 struct ma_state {
386 struct maple_tree *tree; /* The tree we're operating in */
387 unsigned long index; /* The index we're operating on - range start */
388 unsigned long last; /* The last index we're operating on - range end */
389 struct maple_enode *node; /* The node containing this entry */
390 unsigned long min; /* The minimum index of this node - implied pivot min */
391 unsigned long max; /* The maximum index of this node - implied pivot max */
392 struct maple_alloc *alloc; /* Allocated nodes for this operation */
393 unsigned char depth; /* depth of tree descent during write */
394 unsigned char offset;
395 unsigned char mas_flags;
396 };
397
398 struct ma_wr_state {
399 struct ma_state *mas;
400 struct maple_node *node; /* Decoded mas->node */
401 unsigned long r_min; /* range min */
402 unsigned long r_max; /* range max */
403 enum maple_type type; /* mas->node type */
404 unsigned char offset_end; /* The offset where the write ends */
405 unsigned char node_end; /* mas->node end */
406 unsigned long *pivots; /* mas->node->pivots pointer */
407 unsigned long end_piv; /* The pivot at the offset end */
408 void __rcu **slots; /* mas->node->slots pointer */
409 void *entry; /* The entry to write */
410 void *content; /* The existing entry that is being overwritten */
411 };
412
413 #define mas_lock(mas) spin_lock(&((mas)->tree->ma_lock))
414 #define mas_lock_nested(mas, subclass) \
415 spin_lock_nested(&((mas)->tree->ma_lock), subclass)
416 #define mas_unlock(mas) spin_unlock(&((mas)->tree->ma_lock))
417
418
419 /*
420 * Special values for ma_state.node.
421 * MAS_START means we have not searched the tree.
422 * MAS_ROOT means we have searched the tree and the entry we found lives in
423 * the root of the tree (ie it has index 0, length 1 and is the only entry in
424 * the tree).
425 * MAS_NONE means we have searched the tree and there is no node in the
426 * tree for this entry. For example, we searched for index 1 in an empty
427 * tree. Or we have a tree which points to a full leaf node and we
428 * searched for an entry which is larger than can be contained in that
429 * leaf node.
430 * MA_ERROR represents an errno. After dropping the lock and attempting
431 * to resolve the error, the walk would have to be restarted from the
432 * top of the tree as the tree may have been modified.
433 */
434 #define MAS_START ((struct maple_enode *)1UL)
435 #define MAS_ROOT ((struct maple_enode *)5UL)
436 #define MAS_NONE ((struct maple_enode *)9UL)
437 #define MAS_PAUSE ((struct maple_enode *)17UL)
438 #define MAS_OVERFLOW ((struct maple_enode *)33UL)
439 #define MAS_UNDERFLOW ((struct maple_enode *)65UL)
440 #define MA_ERROR(err) \
441 ((struct maple_enode *)(((unsigned long)err << 2) | 2UL))
442
443 #define MA_STATE(name, mt, first, end) \
444 struct ma_state name = { \
445 .tree = mt, \
446 .index = first, \
447 .last = end, \
448 .node = MAS_START, \
449 .min = 0, \
450 .max = ULONG_MAX, \
451 .alloc = NULL, \
452 .mas_flags = 0, \
453 }
454
455 #define MA_WR_STATE(name, ma_state, wr_entry) \
456 struct ma_wr_state name = { \
457 .mas = ma_state, \
458 .content = NULL, \
459 .entry = wr_entry, \
460 }
461
462 #define MA_TOPIARY(name, tree) \
463 struct ma_topiary name = { \
464 .head = NULL, \
465 .tail = NULL, \
466 .mtree = tree, \
467 }
468
469 void *mas_walk(struct ma_state *mas);
470 void *mas_store(struct ma_state *mas, void *entry);
471 void *mas_erase(struct ma_state *mas);
472 int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp);
473 void mas_store_prealloc(struct ma_state *mas, void *entry);
474 void *mas_find(struct ma_state *mas, unsigned long max);
475 void *mas_find_range(struct ma_state *mas, unsigned long max);
476 void *mas_find_rev(struct ma_state *mas, unsigned long min);
477 void *mas_find_range_rev(struct ma_state *mas, unsigned long max);
478 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp);
479 bool mas_is_err(struct ma_state *mas);
480
481 bool mas_nomem(struct ma_state *mas, gfp_t gfp);
482 void mas_pause(struct ma_state *mas);
483 void maple_tree_init(void);
484 void mas_destroy(struct ma_state *mas);
485 int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries);
486
487 void *mas_prev(struct ma_state *mas, unsigned long min);
488 void *mas_prev_range(struct ma_state *mas, unsigned long max);
489 void *mas_next(struct ma_state *mas, unsigned long max);
490 void *mas_next_range(struct ma_state *mas, unsigned long max);
491
492 int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max,
493 unsigned long size);
494 /*
495 * This finds an empty area from the highest address to the lowest.
496 * AKA "Topdown" version,
497 */
498 int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
499 unsigned long max, unsigned long size);
500
mas_init(struct ma_state * mas,struct maple_tree * tree,unsigned long addr)501 static inline void mas_init(struct ma_state *mas, struct maple_tree *tree,
502 unsigned long addr)
503 {
504 memset(mas, 0, sizeof(struct ma_state));
505 mas->tree = tree;
506 mas->index = mas->last = addr;
507 mas->max = ULONG_MAX;
508 mas->node = MAS_START;
509 }
510
511 /* Checks if a mas has not found anything */
mas_is_none(const struct ma_state * mas)512 static inline bool mas_is_none(const struct ma_state *mas)
513 {
514 return mas->node == MAS_NONE;
515 }
516
517 /* Checks if a mas has been paused */
mas_is_paused(const struct ma_state * mas)518 static inline bool mas_is_paused(const struct ma_state *mas)
519 {
520 return mas->node == MAS_PAUSE;
521 }
522
523 /* Check if the mas is pointing to a node or not */
mas_is_active(struct ma_state * mas)524 static inline bool mas_is_active(struct ma_state *mas)
525 {
526 if ((unsigned long)mas->node >= MAPLE_RESERVED_RANGE)
527 return true;
528
529 return false;
530 }
531
532 /**
533 * mas_reset() - Reset a Maple Tree operation state.
534 * @mas: Maple Tree operation state.
535 *
536 * Resets the error or walk state of the @mas so future walks of the
537 * array will start from the root. Use this if you have dropped the
538 * lock and want to reuse the ma_state.
539 *
540 * Context: Any context.
541 */
mas_reset(struct ma_state * mas)542 static inline void mas_reset(struct ma_state *mas)
543 {
544 mas->node = MAS_START;
545 }
546
547 /**
548 * mas_for_each() - Iterate over a range of the maple tree.
549 * @__mas: Maple Tree operation state (maple_state)
550 * @__entry: Entry retrieved from the tree
551 * @__max: maximum index to retrieve from the tree
552 *
553 * When returned, mas->index and mas->last will hold the entire range for the
554 * entry.
555 *
556 * Note: may return the zero entry.
557 */
558 #define mas_for_each(__mas, __entry, __max) \
559 while (((__entry) = mas_find((__mas), (__max))) != NULL)
560 /**
561 * __mas_set_range() - Set up Maple Tree operation state to a sub-range of the
562 * current location.
563 * @mas: Maple Tree operation state.
564 * @start: New start of range in the Maple Tree.
565 * @last: New end of range in the Maple Tree.
566 *
567 * set the internal maple state values to a sub-range.
568 * Please use mas_set_range() if you do not know where you are in the tree.
569 */
__mas_set_range(struct ma_state * mas,unsigned long start,unsigned long last)570 static inline void __mas_set_range(struct ma_state *mas, unsigned long start,
571 unsigned long last)
572 {
573 mas->index = start;
574 mas->last = last;
575 }
576
577 /**
578 * mas_set_range() - Set up Maple Tree operation state for a different index.
579 * @mas: Maple Tree operation state.
580 * @start: New start of range in the Maple Tree.
581 * @last: New end of range in the Maple Tree.
582 *
583 * Move the operation state to refer to a different range. This will
584 * have the effect of starting a walk from the top; see mas_next()
585 * to move to an adjacent index.
586 */
587 static inline
mas_set_range(struct ma_state * mas,unsigned long start,unsigned long last)588 void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last)
589 {
590 __mas_set_range(mas, start, last);
591 mas->node = MAS_START;
592 }
593
594 /**
595 * mas_set() - Set up Maple Tree operation state for a different index.
596 * @mas: Maple Tree operation state.
597 * @index: New index into the Maple Tree.
598 *
599 * Move the operation state to refer to a different index. This will
600 * have the effect of starting a walk from the top; see mas_next()
601 * to move to an adjacent index.
602 */
mas_set(struct ma_state * mas,unsigned long index)603 static inline void mas_set(struct ma_state *mas, unsigned long index)
604 {
605
606 mas_set_range(mas, index, index);
607 }
608
mt_external_lock(const struct maple_tree * mt)609 static inline bool mt_external_lock(const struct maple_tree *mt)
610 {
611 return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN;
612 }
613
614 /**
615 * mt_init_flags() - Initialise an empty maple tree with flags.
616 * @mt: Maple Tree
617 * @flags: maple tree flags.
618 *
619 * If you need to initialise a Maple Tree with special flags (eg, an
620 * allocation tree), use this function.
621 *
622 * Context: Any context.
623 */
mt_init_flags(struct maple_tree * mt,unsigned int flags)624 static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags)
625 {
626 mt->ma_flags = flags;
627 if (!mt_external_lock(mt))
628 spin_lock_init(&mt->ma_lock);
629 rcu_assign_pointer(mt->ma_root, NULL);
630 }
631
632 /**
633 * mt_init() - Initialise an empty maple tree.
634 * @mt: Maple Tree
635 *
636 * An empty Maple Tree.
637 *
638 * Context: Any context.
639 */
mt_init(struct maple_tree * mt)640 static inline void mt_init(struct maple_tree *mt)
641 {
642 mt_init_flags(mt, 0);
643 }
644
mt_in_rcu(struct maple_tree * mt)645 static inline bool mt_in_rcu(struct maple_tree *mt)
646 {
647 #ifdef CONFIG_MAPLE_RCU_DISABLED
648 return false;
649 #endif
650 return mt->ma_flags & MT_FLAGS_USE_RCU;
651 }
652
653 /**
654 * mt_clear_in_rcu() - Switch the tree to non-RCU mode.
655 * @mt: The Maple Tree
656 */
mt_clear_in_rcu(struct maple_tree * mt)657 static inline void mt_clear_in_rcu(struct maple_tree *mt)
658 {
659 if (!mt_in_rcu(mt))
660 return;
661
662 if (mt_external_lock(mt)) {
663 WARN_ON(!mt_lock_is_held(mt));
664 mt->ma_flags &= ~MT_FLAGS_USE_RCU;
665 } else {
666 mtree_lock(mt);
667 mt->ma_flags &= ~MT_FLAGS_USE_RCU;
668 mtree_unlock(mt);
669 }
670 }
671
672 /**
673 * mt_set_in_rcu() - Switch the tree to RCU safe mode.
674 * @mt: The Maple Tree
675 */
mt_set_in_rcu(struct maple_tree * mt)676 static inline void mt_set_in_rcu(struct maple_tree *mt)
677 {
678 if (mt_in_rcu(mt))
679 return;
680
681 if (mt_external_lock(mt)) {
682 WARN_ON(!mt_lock_is_held(mt));
683 mt->ma_flags |= MT_FLAGS_USE_RCU;
684 } else {
685 mtree_lock(mt);
686 mt->ma_flags |= MT_FLAGS_USE_RCU;
687 mtree_unlock(mt);
688 }
689 }
690
mt_height(const struct maple_tree * mt)691 static inline unsigned int mt_height(const struct maple_tree *mt)
692 {
693 return (mt->ma_flags & MT_FLAGS_HEIGHT_MASK) >> MT_FLAGS_HEIGHT_OFFSET;
694 }
695
696 void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max);
697 void *mt_find_after(struct maple_tree *mt, unsigned long *index,
698 unsigned long max);
699 void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min);
700 void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max);
701
702 /**
703 * mt_for_each - Iterate over each entry starting at index until max.
704 * @__tree: The Maple Tree
705 * @__entry: The current entry
706 * @__index: The index to start the search from. Subsequently used as iterator.
707 * @__max: The maximum limit for @index
708 *
709 * This iterator skips all entries, which resolve to a NULL pointer,
710 * e.g. entries which has been reserved with XA_ZERO_ENTRY.
711 */
712 #define mt_for_each(__tree, __entry, __index, __max) \
713 for (__entry = mt_find(__tree, &(__index), __max); \
714 __entry; __entry = mt_find_after(__tree, &(__index), __max))
715
716
717 #ifdef CONFIG_DEBUG_MAPLE_TREE
718 enum mt_dump_format {
719 mt_dump_dec,
720 mt_dump_hex,
721 };
722
723 extern atomic_t maple_tree_tests_run;
724 extern atomic_t maple_tree_tests_passed;
725
726 void mt_dump(const struct maple_tree *mt, enum mt_dump_format format);
727 void mas_dump(const struct ma_state *mas);
728 void mas_wr_dump(const struct ma_wr_state *wr_mas);
729 void mt_validate(struct maple_tree *mt);
730 void mt_cache_shrink(void);
731 #define MT_BUG_ON(__tree, __x) do { \
732 atomic_inc(&maple_tree_tests_run); \
733 if (__x) { \
734 pr_info("BUG at %s:%d (%u)\n", \
735 __func__, __LINE__, __x); \
736 mt_dump(__tree, mt_dump_hex); \
737 pr_info("Pass: %u Run:%u\n", \
738 atomic_read(&maple_tree_tests_passed), \
739 atomic_read(&maple_tree_tests_run)); \
740 dump_stack(); \
741 } else { \
742 atomic_inc(&maple_tree_tests_passed); \
743 } \
744 } while (0)
745
746 #define MAS_BUG_ON(__mas, __x) do { \
747 atomic_inc(&maple_tree_tests_run); \
748 if (__x) { \
749 pr_info("BUG at %s:%d (%u)\n", \
750 __func__, __LINE__, __x); \
751 mas_dump(__mas); \
752 mt_dump((__mas)->tree, mt_dump_hex); \
753 pr_info("Pass: %u Run:%u\n", \
754 atomic_read(&maple_tree_tests_passed), \
755 atomic_read(&maple_tree_tests_run)); \
756 dump_stack(); \
757 } else { \
758 atomic_inc(&maple_tree_tests_passed); \
759 } \
760 } while (0)
761
762 #define MAS_WR_BUG_ON(__wrmas, __x) do { \
763 atomic_inc(&maple_tree_tests_run); \
764 if (__x) { \
765 pr_info("BUG at %s:%d (%u)\n", \
766 __func__, __LINE__, __x); \
767 mas_wr_dump(__wrmas); \
768 mas_dump((__wrmas)->mas); \
769 mt_dump((__wrmas)->mas->tree, mt_dump_hex); \
770 pr_info("Pass: %u Run:%u\n", \
771 atomic_read(&maple_tree_tests_passed), \
772 atomic_read(&maple_tree_tests_run)); \
773 dump_stack(); \
774 } else { \
775 atomic_inc(&maple_tree_tests_passed); \
776 } \
777 } while (0)
778
779 #define MT_WARN_ON(__tree, __x) ({ \
780 int ret = !!(__x); \
781 atomic_inc(&maple_tree_tests_run); \
782 if (ret) { \
783 pr_info("WARN at %s:%d (%u)\n", \
784 __func__, __LINE__, __x); \
785 mt_dump(__tree, mt_dump_hex); \
786 pr_info("Pass: %u Run:%u\n", \
787 atomic_read(&maple_tree_tests_passed), \
788 atomic_read(&maple_tree_tests_run)); \
789 dump_stack(); \
790 } else { \
791 atomic_inc(&maple_tree_tests_passed); \
792 } \
793 unlikely(ret); \
794 })
795
796 #define MAS_WARN_ON(__mas, __x) ({ \
797 int ret = !!(__x); \
798 atomic_inc(&maple_tree_tests_run); \
799 if (ret) { \
800 pr_info("WARN at %s:%d (%u)\n", \
801 __func__, __LINE__, __x); \
802 mas_dump(__mas); \
803 mt_dump((__mas)->tree, mt_dump_hex); \
804 pr_info("Pass: %u Run:%u\n", \
805 atomic_read(&maple_tree_tests_passed), \
806 atomic_read(&maple_tree_tests_run)); \
807 dump_stack(); \
808 } else { \
809 atomic_inc(&maple_tree_tests_passed); \
810 } \
811 unlikely(ret); \
812 })
813
814 #define MAS_WR_WARN_ON(__wrmas, __x) ({ \
815 int ret = !!(__x); \
816 atomic_inc(&maple_tree_tests_run); \
817 if (ret) { \
818 pr_info("WARN at %s:%d (%u)\n", \
819 __func__, __LINE__, __x); \
820 mas_wr_dump(__wrmas); \
821 mas_dump((__wrmas)->mas); \
822 mt_dump((__wrmas)->mas->tree, mt_dump_hex); \
823 pr_info("Pass: %u Run:%u\n", \
824 atomic_read(&maple_tree_tests_passed), \
825 atomic_read(&maple_tree_tests_run)); \
826 dump_stack(); \
827 } else { \
828 atomic_inc(&maple_tree_tests_passed); \
829 } \
830 unlikely(ret); \
831 })
832 #else
833 #define MT_BUG_ON(__tree, __x) BUG_ON(__x)
834 #define MAS_BUG_ON(__mas, __x) BUG_ON(__x)
835 #define MAS_WR_BUG_ON(__mas, __x) BUG_ON(__x)
836 #define MT_WARN_ON(__tree, __x) WARN_ON(__x)
837 #define MAS_WARN_ON(__mas, __x) WARN_ON(__x)
838 #define MAS_WR_WARN_ON(__mas, __x) WARN_ON(__x)
839 #endif /* CONFIG_DEBUG_MAPLE_TREE */
840
841 #endif /*_LINUX_MAPLE_TREE_H */
842