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
56 * range type is done by examining the immutable tree flag for the
57 * MT_FLAGS_ALLOC_RANGE flag.
58 *
59 * Node types:
60 * 0b??1 = Root
61 * 0b?00 = 16 bit nodes
62 * 0b010 = 32 bit nodes
63 * 0b110 = 64 bit nodes
64 *
65 * Slot size and location in the parent pointer:
66 * type : slot location
67 * 0b??1 : Root
68 * 0b?00 : 16 bit values, type in 0-1, slot in 2-6
69 * 0b010 : 32 bit values, type in 0-2, slot in 3-6
70 * 0b110 : 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 */
77struct maple_metadata {
78 unsigned char end; /* end of data */
79 unsigned char gap; /* offset of largest 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
103struct 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 */
124struct 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
132struct 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
139struct maple_topiary {
140 struct maple_pnode *parent;
141 struct maple_enode *next; /* Overlaps the pivot */
142};
143
144enum maple_type {
145 maple_dense,
146 maple_leaf_64,
147 maple_range_64,
148 maple_arange_64,
149};
150
151enum store_type {
152 wr_invalid,
153 wr_new_root,
154 wr_store_root,
155 wr_exact_fit,
156 wr_spanning_store,
157 wr_split_store,
158 wr_rebalance,
159 wr_append,
160 wr_node_store,
161 wr_slot_store,
162};
163
164/**
165 * DOC: Maple tree flags
166 *
167 * * MT_FLAGS_ALLOC_RANGE - Track gaps in this tree
168 * * MT_FLAGS_USE_RCU - Operate in RCU mode
169 * * MT_FLAGS_HEIGHT_OFFSET - The position of the tree height in the flags
170 * * MT_FLAGS_HEIGHT_MASK - The mask for the maple tree height value
171 * * MT_FLAGS_LOCK_MASK - How the mt_lock is used
172 * * MT_FLAGS_LOCK_IRQ - Acquired irq-safe
173 * * MT_FLAGS_LOCK_BH - Acquired bh-safe
174 * * MT_FLAGS_LOCK_EXTERN - mt_lock is not used
175 *
176 * MAPLE_HEIGHT_MAX The largest height that can be stored
177 */
178#define MT_FLAGS_ALLOC_RANGE 0x01
179#define MT_FLAGS_USE_RCU 0x02
180#define MT_FLAGS_HEIGHT_OFFSET 0x02
181#define MT_FLAGS_HEIGHT_MASK 0x7C
182#define MT_FLAGS_LOCK_MASK 0x300
183#define MT_FLAGS_LOCK_IRQ 0x100
184#define MT_FLAGS_LOCK_BH 0x200
185#define MT_FLAGS_LOCK_EXTERN 0x300
186#define MT_FLAGS_ALLOC_WRAPPED 0x0800
187
188#define MAPLE_HEIGHT_MAX 31
189
190
191#define MAPLE_NODE_TYPE_MASK 0x0F
192#define MAPLE_NODE_TYPE_SHIFT 0x03
193
194#define MAPLE_RESERVED_RANGE 4096
195
196#ifdef CONFIG_LOCKDEP
197#define mt_lock_is_held(mt) \
198 (!(mt)->ma_external_lock || lock_is_held((mt)->ma_external_lock))
199
200#define mt_write_lock_is_held(mt) \
201 (!(mt)->ma_external_lock || \
202 lock_is_held_type((mt)->ma_external_lock, 0))
203
204#define mt_set_external_lock(mt, lock) \
205 (mt)->ma_external_lock = &(lock)->dep_map
206
207#define mt_on_stack(mt) (mt).ma_external_lock = NULL
208#else
209#define mt_lock_is_held(mt) 1
210#define mt_write_lock_is_held(mt) 1
211#define mt_set_external_lock(mt, lock) do { } while (0)
212#define mt_on_stack(mt) do { } while (0)
213#endif
214
215/*
216 * If the tree contains a single entry at index 0, it is usually stored in
217 * tree->ma_root. To optimise for the page cache, an entry which ends in '00',
218 * '01' or '11' is stored in the root, but an entry which ends in '10' will be
219 * stored in a node. Bits 3-6 are used to store enum maple_type.
220 *
221 * The flags are used both to store some immutable information about this tree
222 * (set at tree creation time) and dynamic information set under the spinlock.
223 *
224 * Another use of flags are to indicate global states of the tree. This is the
225 * case with the MT_FLAGS_USE_RCU flag, which indicates the tree is currently in
226 * RCU mode. This mode was added to allow the tree to reuse nodes instead of
227 * re-allocating and RCU freeing nodes when there is a single user.
228 */
229struct maple_tree {
230 union {
231 spinlock_t ma_lock;
232#ifdef CONFIG_LOCKDEP
233 struct lockdep_map *ma_external_lock;
234#endif
235 };
236 unsigned int ma_flags;
237 void __rcu *ma_root;
238};
239
240/**
241 * MTREE_INIT() - Initialize a maple tree
242 * @name: The maple tree name
243 * @__flags: The maple tree flags
244 *
245 */
246#define MTREE_INIT(name, __flags) { \
247 .ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock), \
248 .ma_flags = __flags, \
249 .ma_root = NULL, \
250}
251
252/**
253 * MTREE_INIT_EXT() - Initialize a maple tree with an external lock.
254 * @name: The tree name
255 * @__flags: The maple tree flags
256 * @__lock: The external lock
257 */
258#ifdef CONFIG_LOCKDEP
259#define MTREE_INIT_EXT(name, __flags, __lock) { \
260 .ma_external_lock = &(__lock).dep_map, \
261 .ma_flags = (__flags), \
262 .ma_root = NULL, \
263}
264#else
265#define MTREE_INIT_EXT(name, __flags, __lock) MTREE_INIT(name, __flags)
266#endif
267
268#define DEFINE_MTREE(name) \
269 struct maple_tree name = MTREE_INIT(name, 0)
270
271#define mtree_lock(mt) spin_lock((&(mt)->ma_lock))
272#define mtree_lock_nested(mas, subclass) \
273 spin_lock_nested((&(mt)->ma_lock), subclass)
274#define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock))
275
276/*
277 * The Maple Tree squeezes various bits in at various points which aren't
278 * necessarily obvious. Usually, this is done by observing that pointers are
279 * N-byte aligned and thus the bottom log_2(N) bits are available for use. We
280 * don't use the high bits of pointers to store additional information because
281 * we don't know what bits are unused on any given architecture.
282 *
283 * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
284 * low bits for our own purposes. Nodes are currently of 4 types:
285 * 1. Single pointer (Range is 0-0)
286 * 2. Non-leaf Allocation Range nodes
287 * 3. Non-leaf Range nodes
288 * 4. Leaf Range nodes All nodes consist of a number of node slots,
289 * pivots, and a parent pointer.
290 */
291
292struct maple_node {
293 union {
294 struct {
295 struct maple_pnode *parent;
296 void __rcu *slot[MAPLE_NODE_SLOTS];
297 };
298 struct {
299 void *pad;
300 struct rcu_head rcu;
301 struct maple_enode *piv_parent;
302 unsigned char parent_slot;
303 enum maple_type type;
304 unsigned char slot_len;
305 unsigned int ma_flags;
306 };
307 struct maple_range_64 mr64;
308 struct maple_arange_64 ma64;
309 struct maple_alloc alloc;
310 };
311};
312
313/*
314 * More complicated stores can cause two nodes to become one or three and
315 * potentially alter the height of the tree. Either half of the tree may need
316 * to be rebalanced against the other. The ma_topiary struct is used to track
317 * which nodes have been 'cut' from the tree so that the change can be done
318 * safely at a later date. This is done to support RCU.
319 */
320struct ma_topiary {
321 struct maple_enode *head;
322 struct maple_enode *tail;
323 struct maple_tree *mtree;
324};
325
326void *mtree_load(struct maple_tree *mt, unsigned long index);
327
328int mtree_insert(struct maple_tree *mt, unsigned long index,
329 void *entry, gfp_t gfp);
330int mtree_insert_range(struct maple_tree *mt, unsigned long first,
331 unsigned long last, void *entry, gfp_t gfp);
332int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
333 void *entry, unsigned long size, unsigned long min,
334 unsigned long max, gfp_t gfp);
335int mtree_alloc_cyclic(struct maple_tree *mt, unsigned long *startp,
336 void *entry, unsigned long range_lo, unsigned long range_hi,
337 unsigned long *next, gfp_t gfp);
338int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
339 void *entry, unsigned long size, unsigned long min,
340 unsigned long max, gfp_t gfp);
341
342int mtree_store_range(struct maple_tree *mt, unsigned long first,
343 unsigned long last, void *entry, gfp_t gfp);
344int mtree_store(struct maple_tree *mt, unsigned long index,
345 void *entry, gfp_t gfp);
346void *mtree_erase(struct maple_tree *mt, unsigned long index);
347
348int mtree_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp);
349int __mt_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp);
350
351void mtree_destroy(struct maple_tree *mt);
352void __mt_destroy(struct maple_tree *mt);
353
354/**
355 * mtree_empty() - Determine if a tree has any present entries.
356 * @mt: Maple Tree.
357 *
358 * Context: Any context.
359 * Return: %true if the tree contains only NULL pointers.
360 */
361static inline bool mtree_empty(const struct maple_tree *mt)
362{
363 return mt->ma_root == NULL;
364}
365
366/* Advanced API */
367
368/*
369 * Maple State Status
370 * ma_active means the maple state is pointing to a node and offset and can
371 * continue operating on the tree.
372 * ma_start means we have not searched the tree.
373 * ma_root means we have searched the tree and the entry we found lives in
374 * the root of the tree (ie it has index 0, length 1 and is the only entry in
375 * the tree).
376 * ma_none means we have searched the tree and there is no node in the
377 * tree for this entry. For example, we searched for index 1 in an empty
378 * tree. Or we have a tree which points to a full leaf node and we
379 * searched for an entry which is larger than can be contained in that
380 * leaf node.
381 * ma_pause means the data within the maple state may be stale, restart the
382 * operation
383 * ma_overflow means the search has reached the upper limit of the search
384 * ma_underflow means the search has reached the lower limit of the search
385 * ma_error means there was an error, check the node for the error number.
386 */
387enum maple_status {
388 ma_active,
389 ma_start,
390 ma_root,
391 ma_none,
392 ma_pause,
393 ma_overflow,
394 ma_underflow,
395 ma_error,
396};
397
398/*
399 * The maple state is defined in the struct ma_state and is used to keep track
400 * of information during operations, and even between operations when using the
401 * advanced API.
402 *
403 * If state->node has bit 0 set then it references a tree location which is not
404 * a node (eg the root). If bit 1 is set, the rest of the bits are a negative
405 * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the
406 * node type.
407 *
408 * state->alloc either has a request number of nodes or an allocated node. If
409 * stat->alloc has a requested number of nodes, the first bit will be set (0x1)
410 * and the remaining bits are the value. If state->alloc is a node, then the
411 * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for
412 * storing more allocated nodes, a total number of nodes allocated, and the
413 * node_count in this node. node_count is the number of allocated nodes in this
414 * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
415 * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc
416 * by removing a node from the state->alloc node until state->alloc->node_count
417 * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
418 * to state->alloc. Nodes are pushed onto state->alloc by putting the current
419 * state->alloc into the pushed node's slot[0].
420 *
421 * The state also contains the implied min/max of the state->node, the depth of
422 * this search, and the offset. The implied min/max are either from the parent
423 * node or are 0-oo for the root node. The depth is incremented or decremented
424 * every time a node is walked down or up. The offset is the slot/pivot of
425 * interest in the node - either for reading or writing.
426 *
427 * When returning a value the maple state index and last respectively contain
428 * the start and end of the range for the entry. Ranges are inclusive in the
429 * Maple Tree.
430 *
431 * The status of the state is used to determine how the next action should treat
432 * the state. For instance, if the status is ma_start then the next action
433 * should start at the root of the tree and walk down. If the status is
434 * ma_pause then the node may be stale data and should be discarded. If the
435 * status is ma_overflow, then the last action hit the upper limit.
436 *
437 */
438struct ma_state {
439 struct maple_tree *tree; /* The tree we're operating in */
440 unsigned long index; /* The index we're operating on - range start */
441 unsigned long last; /* The last index we're operating on - range end */
442 struct maple_enode *node; /* The node containing this entry */
443 unsigned long min; /* The minimum index of this node - implied pivot min */
444 unsigned long max; /* The maximum index of this node - implied pivot max */
445 struct slab_sheaf *sheaf; /* Allocated nodes for this operation */
446 struct maple_node *alloc; /* A single allocated node for fast path writes */
447 unsigned long node_request; /* The number of nodes to allocate for this operation */
448 enum maple_status status; /* The status of the state (active, start, none, etc) */
449 unsigned char depth; /* depth of tree descent during write */
450 unsigned char offset;
451 unsigned char mas_flags;
452 unsigned char end; /* The end of the node */
453 enum store_type store_type; /* The type of store needed for this operation */
454};
455
456struct ma_wr_state {
457 struct ma_state *mas;
458 struct maple_node *node; /* Decoded mas->node */
459 unsigned long r_min; /* range min */
460 unsigned long r_max; /* range max */
461 enum maple_type type; /* mas->node type */
462 unsigned char offset_end; /* The offset where the write ends */
463 unsigned long *pivots; /* mas->node->pivots pointer */
464 unsigned long end_piv; /* The pivot at the offset end */
465 void __rcu **slots; /* mas->node->slots pointer */
466 void *entry; /* The entry to write */
467 void *content; /* The existing entry that is being overwritten */
468 unsigned char vacant_height; /* Height of lowest node with free space */
469 unsigned char sufficient_height;/* Height of lowest node with min sufficiency + 1 nodes */
470};
471
472#define mas_lock(mas) spin_lock(&((mas)->tree->ma_lock))
473#define mas_lock_nested(mas, subclass) \
474 spin_lock_nested(&((mas)->tree->ma_lock), subclass)
475#define mas_unlock(mas) spin_unlock(&((mas)->tree->ma_lock))
476
477/*
478 * Special values for ma_state.node.
479 * MA_ERROR represents an errno. After dropping the lock and attempting
480 * to resolve the error, the walk would have to be restarted from the
481 * top of the tree as the tree may have been modified.
482 */
483#define MA_ERROR(err) \
484 ((struct maple_enode *)(((unsigned long)err << 2) | 2UL))
485
486/*
487 * When changing MA_STATE, remember to also change rust/kernel/maple_tree.rs
488 */
489#define MA_STATE(name, mt, first, end) \
490 struct ma_state name = { \
491 .tree = mt, \
492 .index = first, \
493 .last = end, \
494 .node = NULL, \
495 .status = ma_start, \
496 .min = 0, \
497 .max = ULONG_MAX, \
498 .sheaf = NULL, \
499 .alloc = NULL, \
500 .node_request = 0, \
501 .mas_flags = 0, \
502 .store_type = wr_invalid, \
503 }
504
505#define MA_WR_STATE(name, ma_state, wr_entry) \
506 struct ma_wr_state name = { \
507 .mas = ma_state, \
508 .content = NULL, \
509 .entry = wr_entry, \
510 .vacant_height = 0, \
511 .sufficient_height = 0 \
512 }
513
514#define MA_TOPIARY(name, tree) \
515 struct ma_topiary name = { \
516 .head = NULL, \
517 .tail = NULL, \
518 .mtree = tree, \
519 }
520
521void *mas_walk(struct ma_state *mas);
522void *mas_store(struct ma_state *mas, void *entry);
523void *mas_erase(struct ma_state *mas);
524int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp);
525void mas_store_prealloc(struct ma_state *mas, void *entry);
526void *mas_find(struct ma_state *mas, unsigned long max);
527void *mas_find_range(struct ma_state *mas, unsigned long max);
528void *mas_find_rev(struct ma_state *mas, unsigned long min);
529void *mas_find_range_rev(struct ma_state *mas, unsigned long max);
530int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp);
531int mas_alloc_cyclic(struct ma_state *mas, unsigned long *startp,
532 void *entry, unsigned long range_lo, unsigned long range_hi,
533 unsigned long *next, gfp_t gfp);
534
535bool mas_nomem(struct ma_state *mas, gfp_t gfp);
536void mas_pause(struct ma_state *mas);
537void maple_tree_init(void);
538void mas_destroy(struct ma_state *mas);
539int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries);
540
541void *mas_prev(struct ma_state *mas, unsigned long min);
542void *mas_prev_range(struct ma_state *mas, unsigned long max);
543void *mas_next(struct ma_state *mas, unsigned long max);
544void *mas_next_range(struct ma_state *mas, unsigned long max);
545
546int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max,
547 unsigned long size);
548/*
549 * This finds an empty area from the highest address to the lowest.
550 * AKA "Topdown" version,
551 */
552int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
553 unsigned long max, unsigned long size);
554
555static inline void mas_init(struct ma_state *mas, struct maple_tree *tree,
556 unsigned long addr)
557{
558 memset(s: mas, c: 0, n: sizeof(struct ma_state));
559 mas->tree = tree;
560 mas->index = mas->last = addr;
561 mas->max = ULONG_MAX;
562 mas->status = ma_start;
563 mas->node = NULL;
564}
565
566static inline bool mas_is_active(struct ma_state *mas)
567{
568 return mas->status == ma_active;
569}
570
571static inline bool mas_is_err(struct ma_state *mas)
572{
573 return mas->status == ma_error;
574}
575
576/**
577 * mas_reset() - Reset a Maple Tree operation state.
578 * @mas: Maple Tree operation state.
579 *
580 * Resets the error or walk state of the @mas so future walks of the
581 * array will start from the root. Use this if you have dropped the
582 * lock and want to reuse the ma_state.
583 *
584 * Context: Any context.
585 */
586static __always_inline void mas_reset(struct ma_state *mas)
587{
588 mas->status = ma_start;
589 mas->node = NULL;
590}
591
592/**
593 * mas_for_each() - Iterate over a range of the maple tree.
594 * @__mas: Maple Tree operation state (maple_state)
595 * @__entry: Entry retrieved from the tree
596 * @__max: maximum index to retrieve from the tree
597 *
598 * When returned, mas->index and mas->last will hold the entire range for the
599 * entry.
600 *
601 * Note: may return the zero entry.
602 */
603#define mas_for_each(__mas, __entry, __max) \
604 while (((__entry) = mas_find((__mas), (__max))) != NULL)
605
606/**
607 * mas_for_each_rev() - Iterate over a range of the maple tree in reverse order.
608 * @__mas: Maple Tree operation state (maple_state)
609 * @__entry: Entry retrieved from the tree
610 * @__min: minimum index to retrieve from the tree
611 *
612 * When returned, mas->index and mas->last will hold the entire range for the
613 * entry.
614 *
615 * Note: may return the zero entry.
616 */
617#define mas_for_each_rev(__mas, __entry, __min) \
618 while (((__entry) = mas_find_rev((__mas), (__min))) != NULL)
619
620#ifdef CONFIG_DEBUG_MAPLE_TREE
621enum mt_dump_format {
622 mt_dump_dec,
623 mt_dump_hex,
624};
625
626extern atomic_t maple_tree_tests_run;
627extern atomic_t maple_tree_tests_passed;
628
629void mt_dump(const struct maple_tree *mt, enum mt_dump_format format);
630void mas_dump(const struct ma_state *mas);
631void mas_wr_dump(const struct ma_wr_state *wr_mas);
632void mt_validate(struct maple_tree *mt);
633void mt_cache_shrink(void);
634#define MT_BUG_ON(__tree, __x) do { \
635 atomic_inc(&maple_tree_tests_run); \
636 if (__x) { \
637 pr_info("BUG at %s:%d (%u)\n", \
638 __func__, __LINE__, __x); \
639 mt_dump(__tree, mt_dump_hex); \
640 pr_info("Pass: %u Run:%u\n", \
641 atomic_read(&maple_tree_tests_passed), \
642 atomic_read(&maple_tree_tests_run)); \
643 dump_stack(); \
644 } else { \
645 atomic_inc(&maple_tree_tests_passed); \
646 } \
647} while (0)
648
649#define MAS_BUG_ON(__mas, __x) do { \
650 atomic_inc(&maple_tree_tests_run); \
651 if (__x) { \
652 pr_info("BUG at %s:%d (%u)\n", \
653 __func__, __LINE__, __x); \
654 mas_dump(__mas); \
655 mt_dump((__mas)->tree, mt_dump_hex); \
656 pr_info("Pass: %u Run:%u\n", \
657 atomic_read(&maple_tree_tests_passed), \
658 atomic_read(&maple_tree_tests_run)); \
659 dump_stack(); \
660 } else { \
661 atomic_inc(&maple_tree_tests_passed); \
662 } \
663} while (0)
664
665#define MAS_WR_BUG_ON(__wrmas, __x) do { \
666 atomic_inc(&maple_tree_tests_run); \
667 if (__x) { \
668 pr_info("BUG at %s:%d (%u)\n", \
669 __func__, __LINE__, __x); \
670 mas_wr_dump(__wrmas); \
671 mas_dump((__wrmas)->mas); \
672 mt_dump((__wrmas)->mas->tree, mt_dump_hex); \
673 pr_info("Pass: %u Run:%u\n", \
674 atomic_read(&maple_tree_tests_passed), \
675 atomic_read(&maple_tree_tests_run)); \
676 dump_stack(); \
677 } else { \
678 atomic_inc(&maple_tree_tests_passed); \
679 } \
680} while (0)
681
682#define MT_WARN_ON(__tree, __x) ({ \
683 int ret = !!(__x); \
684 atomic_inc(&maple_tree_tests_run); \
685 if (ret) { \
686 pr_info("WARN at %s:%d (%u)\n", \
687 __func__, __LINE__, __x); \
688 mt_dump(__tree, mt_dump_hex); \
689 pr_info("Pass: %u Run:%u\n", \
690 atomic_read(&maple_tree_tests_passed), \
691 atomic_read(&maple_tree_tests_run)); \
692 dump_stack(); \
693 } else { \
694 atomic_inc(&maple_tree_tests_passed); \
695 } \
696 unlikely(ret); \
697})
698
699#define MAS_WARN_ON(__mas, __x) ({ \
700 int ret = !!(__x); \
701 atomic_inc(&maple_tree_tests_run); \
702 if (ret) { \
703 pr_info("WARN at %s:%d (%u)\n", \
704 __func__, __LINE__, __x); \
705 mas_dump(__mas); \
706 mt_dump((__mas)->tree, mt_dump_hex); \
707 pr_info("Pass: %u Run:%u\n", \
708 atomic_read(&maple_tree_tests_passed), \
709 atomic_read(&maple_tree_tests_run)); \
710 dump_stack(); \
711 } else { \
712 atomic_inc(&maple_tree_tests_passed); \
713 } \
714 unlikely(ret); \
715})
716
717#define MAS_WR_WARN_ON(__wrmas, __x) ({ \
718 int ret = !!(__x); \
719 atomic_inc(&maple_tree_tests_run); \
720 if (ret) { \
721 pr_info("WARN at %s:%d (%u)\n", \
722 __func__, __LINE__, __x); \
723 mas_wr_dump(__wrmas); \
724 mas_dump((__wrmas)->mas); \
725 mt_dump((__wrmas)->mas->tree, mt_dump_hex); \
726 pr_info("Pass: %u Run:%u\n", \
727 atomic_read(&maple_tree_tests_passed), \
728 atomic_read(&maple_tree_tests_run)); \
729 dump_stack(); \
730 } else { \
731 atomic_inc(&maple_tree_tests_passed); \
732 } \
733 unlikely(ret); \
734})
735#else
736#define MT_BUG_ON(__tree, __x) BUG_ON(__x)
737#define MAS_BUG_ON(__mas, __x) BUG_ON(__x)
738#define MAS_WR_BUG_ON(__mas, __x) BUG_ON(__x)
739#define MT_WARN_ON(__tree, __x) WARN_ON(__x)
740#define MAS_WARN_ON(__mas, __x) WARN_ON(__x)
741#define MAS_WR_WARN_ON(__mas, __x) WARN_ON(__x)
742#endif /* CONFIG_DEBUG_MAPLE_TREE */
743
744/**
745 * __mas_set_range() - Set up Maple Tree operation state to a sub-range of the
746 * current location.
747 * @mas: Maple Tree operation state.
748 * @start: New start of range in the Maple Tree.
749 * @last: New end of range in the Maple Tree.
750 *
751 * set the internal maple state values to a sub-range.
752 * Please use mas_set_range() if you do not know where you are in the tree.
753 */
754static inline void __mas_set_range(struct ma_state *mas, unsigned long start,
755 unsigned long last)
756{
757 /* Ensure the range starts within the current slot */
758 MAS_WARN_ON(mas, mas_is_active(mas) &&
759 (mas->index > start || mas->last < start));
760 mas->index = start;
761 mas->last = last;
762}
763
764/**
765 * mas_set_range() - Set up Maple Tree operation state for a different index.
766 * @mas: Maple Tree operation state.
767 * @start: New start of range in the Maple Tree.
768 * @last: New end of range in the Maple Tree.
769 *
770 * Move the operation state to refer to a different range. This will
771 * have the effect of starting a walk from the top; see mas_next()
772 * to move to an adjacent index.
773 */
774static inline
775void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last)
776{
777 mas_reset(mas);
778 __mas_set_range(mas, start, last);
779}
780
781/**
782 * mas_set() - Set up Maple Tree operation state for a different index.
783 * @mas: Maple Tree operation state.
784 * @index: New index into the Maple Tree.
785 *
786 * Move the operation state to refer to a different index. This will
787 * have the effect of starting a walk from the top; see mas_next()
788 * to move to an adjacent index.
789 */
790static inline void mas_set(struct ma_state *mas, unsigned long index)
791{
792
793 mas_set_range(mas, start: index, last: index);
794}
795
796static inline bool mt_external_lock(const struct maple_tree *mt)
797{
798 return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN;
799}
800
801/**
802 * mt_init_flags() - Initialise an empty maple tree with flags.
803 * @mt: Maple Tree
804 * @flags: maple tree flags.
805 *
806 * If you need to initialise a Maple Tree with special flags (eg, an
807 * allocation tree), use this function.
808 *
809 * Context: Any context.
810 */
811static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags)
812{
813 mt->ma_flags = flags;
814 if (!mt_external_lock(mt))
815 spin_lock_init(&mt->ma_lock);
816 rcu_assign_pointer(mt->ma_root, NULL);
817}
818
819/**
820 * mt_init() - Initialise an empty maple tree.
821 * @mt: Maple Tree
822 *
823 * An empty Maple Tree.
824 *
825 * Context: Any context.
826 */
827static inline void mt_init(struct maple_tree *mt)
828{
829 mt_init_flags(mt, flags: 0);
830}
831
832static inline bool mt_in_rcu(struct maple_tree *mt)
833{
834#ifdef CONFIG_MAPLE_RCU_DISABLED
835 return false;
836#endif
837 return mt->ma_flags & MT_FLAGS_USE_RCU;
838}
839
840/**
841 * mt_clear_in_rcu() - Switch the tree to non-RCU mode.
842 * @mt: The Maple Tree
843 */
844static inline void mt_clear_in_rcu(struct maple_tree *mt)
845{
846 if (!mt_in_rcu(mt))
847 return;
848
849 if (mt_external_lock(mt)) {
850 WARN_ON(!mt_lock_is_held(mt));
851 mt->ma_flags &= ~MT_FLAGS_USE_RCU;
852 } else {
853 mtree_lock(mt);
854 mt->ma_flags &= ~MT_FLAGS_USE_RCU;
855 mtree_unlock(mt);
856 }
857}
858
859/**
860 * mt_set_in_rcu() - Switch the tree to RCU safe mode.
861 * @mt: The Maple Tree
862 */
863static inline void mt_set_in_rcu(struct maple_tree *mt)
864{
865 if (mt_in_rcu(mt))
866 return;
867
868 if (mt_external_lock(mt)) {
869 WARN_ON(!mt_lock_is_held(mt));
870 mt->ma_flags |= MT_FLAGS_USE_RCU;
871 } else {
872 mtree_lock(mt);
873 mt->ma_flags |= MT_FLAGS_USE_RCU;
874 mtree_unlock(mt);
875 }
876}
877
878static inline unsigned int mt_height(const struct maple_tree *mt)
879{
880 return (mt->ma_flags & MT_FLAGS_HEIGHT_MASK) >> MT_FLAGS_HEIGHT_OFFSET;
881}
882
883void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max);
884void *mt_find_after(struct maple_tree *mt, unsigned long *index,
885 unsigned long max);
886void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min);
887void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max);
888
889/**
890 * mt_for_each - Iterate over each entry starting at index until max.
891 * @__tree: The Maple Tree
892 * @__entry: The current entry
893 * @__index: The index to start the search from. Subsequently used as iterator.
894 * @__max: The maximum limit for @index
895 *
896 * This iterator skips all entries, which resolve to a NULL pointer,
897 * e.g. entries which has been reserved with XA_ZERO_ENTRY.
898 */
899#define mt_for_each(__tree, __entry, __index, __max) \
900 for (__entry = mt_find(__tree, &(__index), __max); \
901 __entry; __entry = mt_find_after(__tree, &(__index), __max))
902
903#endif /*_LINUX_MAPLE_TREE_H */
904