linux - lib/maple

7268 lines · 181.2 KiB

1	// SPDX-License-Identifier: GPL-2.0+
2	/*
3	* Maple Tree implementation
4	* Copyright (c) 2018-2022 Oracle Corporation
5	* Authors: Liam R. Howlett <[email protected]>
6	* Matthew Wilcox <[email protected]>
7	*/
8
9	/*
10	* DOC: Interesting implementation details of the Maple Tree
11	*
12	* Each node type has a number of slots for entries and a number of slots for
13	* pivots. In the case of dense nodes, the pivots are implied by the position
14	* and are simply the slot index + the minimum of the node.
15	*
16	* In regular B-Tree terms, pivots are called keys. The term pivot is used to
17	* indicate that the tree is specifying ranges, Pivots may appear in the
18	* subtree with an entry attached to the value where as keys are unique to a
19	* specific position of a B-tree. Pivot values are inclusive of the slot with
20	* the same index.
21	*
22	*
23	* The following illustrates the layout of a range64 nodes slots and pivots.
24	*
25	*
26	* Slots -> \| 0 \| 1 \| 2 \| ... \| 12 \| 13 \| 14 \| 15 \|
27	* ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬
28	* │ │ │ │ │ │ │ │ └─ Implied maximum
29	* │ │ │ │ │ │ │ └─ Pivot 14
30	* │ │ │ │ │ │ └─ Pivot 13
31	* │ │ │ │ │ └─ Pivot 12
32	* │ │ │ │ └─ Pivot 11
33	* │ │ │ └─ Pivot 2
34	* │ │ └─ Pivot 1
35	* │ └─ Pivot 0
36	* └─ Implied minimum
37	*
38	* Slot contents:
39	* Internal (non-leaf) nodes contain pointers to other nodes.
40	* Leaf nodes contain entries.
41	*
42	* The location of interest is often referred to as an offset. All offsets have
43	* a slot, but the last offset has an implied pivot from the node above (or
44	* UINT_MAX for the root node.
45	*
46	* Ranges complicate certain write activities. When modifying any of
47	* the B-tree variants, it is known that one entry will either be added or
48	* deleted. When modifying the Maple Tree, one store operation may overwrite
49	* the entire data set, or one half of the tree, or the middle half of the tree.
50	*
51	*/
52
53
54	#include <linux/maple_tree.h>
55	#include <linux/xarray.h>
56	#include <linux/types.h>
57	#include <linux/export.h>
58	#include <linux/slab.h>
59	#include <linux/limits.h>
60	#include <asm/barrier.h>
61
62	#define CREATE_TRACE_POINTS
63	#include <trace/events/maple_tree.h>
64
65	#define MA_ROOT_PARENT 1
66
67	/*
68	* Maple state flags
69	* * MA_STATE_BULK - Bulk insert mode
70	* * MA_STATE_REBALANCE - Indicate a rebalance during bulk insert
71	* * MA_STATE_PREALLOC - Preallocated nodes, WARN_ON allocation
72	*/
73	#define MA_STATE_BULK 1
74	#define MA_STATE_REBALANCE 2
75	#define MA_STATE_PREALLOC 4
76
77	#define ma_parent_ptr(x) ((struct maple_pnode *)(x))
78	#define mas_tree_parent(x) ((unsigned long)(x->tree) \| MA_ROOT_PARENT)
79	#define ma_mnode_ptr(x) ((struct maple_node *)(x))
80	#define ma_enode_ptr(x) ((struct maple_enode *)(x))
81	static struct kmem_cache *maple_node_cache;
82
83	#ifdef CONFIG_DEBUG_MAPLE_TREE
84	static const unsigned long mt_max[] = {
85	[maple_dense] = MAPLE_NODE_SLOTS,
86	[maple_leaf_64] = ULONG_MAX,
87	[maple_range_64] = ULONG_MAX,
88	[maple_arange_64] = ULONG_MAX,
89	};
90	#define mt_node_max(x) mt_max[mte_node_type(x)]
91	#endif
92
93	static const unsigned char mt_slots[] = {
94	[maple_dense] = MAPLE_NODE_SLOTS,
95	[maple_leaf_64] = MAPLE_RANGE64_SLOTS,
96	[maple_range_64] = MAPLE_RANGE64_SLOTS,
97	[maple_arange_64] = MAPLE_ARANGE64_SLOTS,
98	};
99	#define mt_slot_count(x) mt_slots[mte_node_type(x)]
100
101	static const unsigned char mt_pivots[] = {
102	[maple_dense] = 0,
103	[maple_leaf_64] = MAPLE_RANGE64_SLOTS - 1,
104	[maple_range_64] = MAPLE_RANGE64_SLOTS - 1,
105	[maple_arange_64] = MAPLE_ARANGE64_SLOTS - 1,
106	};
107	#define mt_pivot_count(x) mt_pivots[mte_node_type(x)]
108
109	static const unsigned char mt_min_slots[] = {
110	[maple_dense] = MAPLE_NODE_SLOTS / 2,
111	[maple_leaf_64] = (MAPLE_RANGE64_SLOTS / 2) - 2,
112	[maple_range_64] = (MAPLE_RANGE64_SLOTS / 2) - 2,
113	[maple_arange_64] = (MAPLE_ARANGE64_SLOTS / 2) - 1,
114	};
115	#define mt_min_slot_count(x) mt_min_slots[mte_node_type(x)]
116
117	#define MAPLE_BIG_NODE_SLOTS (MAPLE_RANGE64_SLOTS * 2 + 2)
118	#define MAPLE_BIG_NODE_GAPS (MAPLE_ARANGE64_SLOTS * 2 + 1)
119
120	struct maple_big_node {
121	struct maple_pnode *parent;
122	unsigned long pivot[MAPLE_BIG_NODE_SLOTS - 1];
123	union {
124	struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS];
125	struct {
126	unsigned long padding[MAPLE_BIG_NODE_GAPS];
127	unsigned long gap[MAPLE_BIG_NODE_GAPS];
128	};
129	};
130	unsigned char b_end;
131	enum maple_type type;
132	};
133
134	/*
135	* The maple_subtree_state is used to build a tree to replace a segment of an
136	* existing tree in a more atomic way. Any walkers of the older tree will hit a
137	* dead node and restart on updates.
138	*/
139	struct maple_subtree_state {
140	struct ma_state orig_l; / Original left side of subtree */
141	struct ma_state orig_r; / Original right side of subtree */
142	struct ma_state l; / New left side of subtree */
143	struct ma_state m; / New middle of subtree (rare) */
144	struct ma_state r; / New right side of subtree */
145	struct ma_topiary free; / nodes to be freed */
146	struct ma_topiary destroy; / Nodes to be destroyed (walked and freed) */
147	struct maple_big_node *bn;
148	};
149
150	#ifdef CONFIG_KASAN_STACK
151	/* Prevent mas_wr_bnode() from exceeding the stack frame limit */
152	#define noinline_for_kasan noinline_for_stack
153	#else
154	#define noinline_for_kasan inline
155	#endif
156
157	/* Functions */
158	static inline struct maple_node *mt_alloc_one(gfp_t gfp)
159	{
160	return kmem_cache_alloc(maple_node_cache, gfp);
161	}
162
163	static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes)
164	{
165	return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes);
166	}
167
168	static inline void mt_free_bulk(size_t size, void __rcu **nodes)
169	{
170	kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes);
171	}
172
173	static void mt_free_rcu(struct rcu_head *head)
174	{
175	struct maple_node *node = container_of(head, struct maple_node, rcu);
176
177	kmem_cache_free(maple_node_cache, node);
178	}
179
180	/*
181	* ma_free_rcu() - Use rcu callback to free a maple node
182	* @node: The node to free
183	*
184	* The maple tree uses the parent pointer to indicate this node is no longer in
185	* use and will be freed.
186	*/
187	static void ma_free_rcu(struct maple_node *node)
188	{
189	WARN_ON(node->parent != ma_parent_ptr(node));
190	call_rcu(&node->rcu, mt_free_rcu);
191	}
192
193	static void mas_set_height(struct ma_state *mas)
194	{
195	unsigned int new_flags = mas->tree->ma_flags;
196
197	new_flags &= ~MT_FLAGS_HEIGHT_MASK;
198	MAS_BUG_ON(mas, mas->depth > MAPLE_HEIGHT_MAX);
199	new_flags \|= mas->depth << MT_FLAGS_HEIGHT_OFFSET;
200	mas->tree->ma_flags = new_flags;
201	}
202
203	static unsigned int mas_mt_height(struct ma_state *mas)
204	{
205	return mt_height(mas->tree);
206	}
207
208	static inline enum maple_type mte_node_type(const struct maple_enode *entry)
209	{
210	return ((unsigned long)entry >> MAPLE_NODE_TYPE_SHIFT) &
211	MAPLE_NODE_TYPE_MASK;
212	}
213
214	static inline bool ma_is_dense(const enum maple_type type)
215	{
216	return type < maple_leaf_64;
217	}
218
219	static inline bool ma_is_leaf(const enum maple_type type)
220	{
221	return type < maple_range_64;
222	}
223
224	static inline bool mte_is_leaf(const struct maple_enode *entry)
225	{
226	return ma_is_leaf(mte_node_type(entry));
227	}
228
229	/*
230	* We also reserve values with the bottom two bits set to '10' which are
231	* below 4096
232	*/
233	static inline bool mt_is_reserved(const void *entry)
234	{
235	return ((unsigned long)entry < MAPLE_RESERVED_RANGE) &&
236	xa_is_internal(entry);
237	}
238
239	static inline void mas_set_err(struct ma_state *mas, long err)
240	{
241	mas->node = MA_ERROR(err);
242	}
243
244	static inline bool mas_is_ptr(const struct ma_state *mas)
245	{
246	return mas->node == MAS_ROOT;
247	}
248
249	static inline bool mas_is_start(const struct ma_state *mas)
250	{
251	return mas->node == MAS_START;
252	}
253
254	bool mas_is_err(struct ma_state *mas)
255	{
256	return xa_is_err(mas->node);
257	}
258
259	static __always_inline bool mas_is_overflow(struct ma_state *mas)
260	{
261	if (unlikely(mas->node == MAS_OVERFLOW))
262	return true;
263
264	return false;
265	}
266
267	static __always_inline bool mas_is_underflow(struct ma_state *mas)
268	{
269	if (unlikely(mas->node == MAS_UNDERFLOW))
270	return true;
271
272	return false;
273	}
274
275	static inline bool mas_searchable(struct ma_state *mas)
276	{
277	if (mas_is_none(mas))
278	return false;
279
280	if (mas_is_ptr(mas))
281	return false;
282
283	return true;
284	}
285
286	static inline struct maple_node mte_to_node(const struct maple_enode entry)
287	{
288	return (struct maple_node *)((unsigned long)entry & ~MAPLE_NODE_MASK);
289	}
290
291	/*
292	* mte_to_mat() - Convert a maple encoded node to a maple topiary node.
293	* @entry: The maple encoded node
294	*
295	* Return: a maple topiary pointer
296	*/
297	static inline struct maple_topiary mte_to_mat(const struct maple_enode entry)
298	{
299	return (struct maple_topiary *)
300	((unsigned long)entry & ~MAPLE_NODE_MASK);
301	}
302
303	/*
304	* mas_mn() - Get the maple state node.
305	* @mas: The maple state
306	*
307	* Return: the maple node (not encoded - bare pointer).
308	*/
309	static inline struct maple_node mas_mn(const struct ma_state mas)
310	{
311	return mte_to_node(mas->node);
312	}
313
314	/*
315	* mte_set_node_dead() - Set a maple encoded node as dead.
316	* @mn: The maple encoded node.
317	*/
318	static inline void mte_set_node_dead(struct maple_enode *mn)
319	{
320	mte_to_node(mn)->parent = ma_parent_ptr(mte_to_node(mn));
321	smp_wmb(); /* Needed for RCU */
322	}
323
324	/* Bit 1 indicates the root is a node */
325	#define MAPLE_ROOT_NODE 0x02
326	/* maple_type stored bit 3-6 */
327	#define MAPLE_ENODE_TYPE_SHIFT 0x03
328	/* Bit 2 means a NULL somewhere below */
329	#define MAPLE_ENODE_NULL 0x04
330
331	static inline struct maple_enode mt_mk_node(const struct maple_node node,
332	enum maple_type type)
333	{
334	return (void *)((unsigned long)node \|
335	(type << MAPLE_ENODE_TYPE_SHIFT) \| MAPLE_ENODE_NULL);
336	}
337
338	static inline void mte_mk_root(const struct maple_enode node)
339	{
340	return (void *)((unsigned long)node \| MAPLE_ROOT_NODE);
341	}
342
343	static inline void mte_safe_root(const struct maple_enode node)
344	{
345	return (void *)((unsigned long)node & ~MAPLE_ROOT_NODE);
346	}
347
348	static inline void mte_set_full(const struct maple_enode node)
349	{
350	return (void *)((unsigned long)node & ~MAPLE_ENODE_NULL);
351	}
352
353	static inline void mte_clear_full(const struct maple_enode node)
354	{
355	return (void *)((unsigned long)node \| MAPLE_ENODE_NULL);
356	}
357
358	static inline bool mte_has_null(const struct maple_enode *node)
359	{
360	return (unsigned long)node & MAPLE_ENODE_NULL;
361	}
362
363	static inline bool ma_is_root(struct maple_node *node)
364	{
365	return ((unsigned long)node->parent & MA_ROOT_PARENT);
366	}
367
368	static inline bool mte_is_root(const struct maple_enode *node)
369	{
370	return ma_is_root(mte_to_node(node));
371	}
372
373	static inline bool mas_is_root_limits(const struct ma_state *mas)
374	{
375	return !mas->min && mas->max == ULONG_MAX;
376	}
377
378	static inline bool mt_is_alloc(struct maple_tree *mt)
379	{
380	return (mt->ma_flags & MT_FLAGS_ALLOC_RANGE);
381	}
382
383	/*
384	* The Parent Pointer
385	* Excluding root, the parent pointer is 256B aligned like all other tree nodes.
386	* When storing a 32 or 64 bit values, the offset can fit into 5 bits. The 16
387	* bit values need an extra bit to store the offset. This extra bit comes from
388	* a reuse of the last bit in the node type. This is possible by using bit 1 to
389	* indicate if bit 2 is part of the type or the slot.
390	*
391	* Note types:
392	* 0x??1 = Root
393	* 0x?00 = 16 bit nodes
394	* 0x010 = 32 bit nodes
395	* 0x110 = 64 bit nodes
396	*
397	* Slot size and alignment
398	* 0b??1 : Root
399	* 0b?00 : 16 bit values, type in 0-1, slot in 2-7
400	* 0b010 : 32 bit values, type in 0-2, slot in 3-7
401	* 0b110 : 64 bit values, type in 0-2, slot in 3-7
402	*/
403
404	#define MAPLE_PARENT_ROOT 0x01
405
406	#define MAPLE_PARENT_SLOT_SHIFT 0x03
407	#define MAPLE_PARENT_SLOT_MASK 0xF8
408
409	#define MAPLE_PARENT_16B_SLOT_SHIFT 0x02
410	#define MAPLE_PARENT_16B_SLOT_MASK 0xFC
411
412	#define MAPLE_PARENT_RANGE64 0x06
413	#define MAPLE_PARENT_RANGE32 0x04
414	#define MAPLE_PARENT_NOT_RANGE16 0x02
415
416	/*
417	* mte_parent_shift() - Get the parent shift for the slot storage.
418	* @parent: The parent pointer cast as an unsigned long
419	* Return: The shift into that pointer to the star to of the slot
420	*/
421	static inline unsigned long mte_parent_shift(unsigned long parent)
422	{
423	/* Note bit 1 == 0 means 16B */
424	if (likely(parent & MAPLE_PARENT_NOT_RANGE16))
425	return MAPLE_PARENT_SLOT_SHIFT;
426
427	return MAPLE_PARENT_16B_SLOT_SHIFT;
428	}
429
430	/*
431	* mte_parent_slot_mask() - Get the slot mask for the parent.
432	* @parent: The parent pointer cast as an unsigned long.
433	* Return: The slot mask for that parent.
434	*/
435	static inline unsigned long mte_parent_slot_mask(unsigned long parent)
436	{
437	/* Note bit 1 == 0 means 16B */
438	if (likely(parent & MAPLE_PARENT_NOT_RANGE16))
439	return MAPLE_PARENT_SLOT_MASK;
440
441	return MAPLE_PARENT_16B_SLOT_MASK;
442	}
443
444	/*
445	* mas_parent_type() - Return the maple_type of the parent from the stored
446	* parent type.
447	* @mas: The maple state
448	* @enode: The maple_enode to extract the parent's enum
449	* Return: The node->parent maple_type
450	*/
451	static inline
452	enum maple_type mas_parent_type(struct ma_state mas, struct maple_enode enode)
453	{
454	unsigned long p_type;
455
456	p_type = (unsigned long)mte_to_node(enode)->parent;
457	if (WARN_ON(p_type & MAPLE_PARENT_ROOT))
458	return 0;
459
460	p_type &= MAPLE_NODE_MASK;
461	p_type &= ~mte_parent_slot_mask(p_type);
462	switch (p_type) {
463	case MAPLE_PARENT_RANGE64: /* or MAPLE_PARENT_ARANGE64 */
464	if (mt_is_alloc(mas->tree))
465	return maple_arange_64;
466	return maple_range_64;
467	}
468
469	return 0;
470	}
471
472	/*
473	* mas_set_parent() - Set the parent node and encode the slot
474	* @enode: The encoded maple node.
475	* @parent: The encoded maple node that is the parent of @enode.
476	* @slot: The slot that @enode resides in @parent.
477	*
478	* Slot number is encoded in the enode->parent bit 3-6 or 2-6, depending on the
479	* parent type.
480	*/
481	static inline
482	void mas_set_parent(struct ma_state mas, struct maple_enode enode,
483	const struct maple_enode *parent, unsigned char slot)
484	{
485	unsigned long val = (unsigned long)parent;
486	unsigned long shift;
487	unsigned long type;
488	enum maple_type p_type = mte_node_type(parent);
489
490	MAS_BUG_ON(mas, p_type == maple_dense);
491	MAS_BUG_ON(mas, p_type == maple_leaf_64);
492
493	switch (p_type) {
494	case maple_range_64:
495	case maple_arange_64:
496	shift = MAPLE_PARENT_SLOT_SHIFT;
497	type = MAPLE_PARENT_RANGE64;
498	break;
499	default:
500	case maple_dense:
501	case maple_leaf_64:
502	shift = type = 0;
503	break;
504	}
505
506	val &= ~MAPLE_NODE_MASK; /* Clear all node metadata in parent */
507	val \|= (slot << shift) \| type;
508	mte_to_node(enode)->parent = ma_parent_ptr(val);
509	}
510
511	/*
512	* mte_parent_slot() - get the parent slot of @enode.
513	* @enode: The encoded maple node.
514	*
515	* Return: The slot in the parent node where @enode resides.
516	*/
517	static inline unsigned int mte_parent_slot(const struct maple_enode *enode)
518	{
519	unsigned long val = (unsigned long)mte_to_node(enode)->parent;
520
521	if (val & MA_ROOT_PARENT)
522	return 0;
523
524	/*
525	* Okay to use MAPLE_PARENT_16B_SLOT_MASK as the last bit will be lost
526	* by shift if the parent shift is MAPLE_PARENT_SLOT_SHIFT
527	*/
528	return (val & MAPLE_PARENT_16B_SLOT_MASK) >> mte_parent_shift(val);
529	}
530
531	/*
532	* mte_parent() - Get the parent of @node.
533	* @node: The encoded maple node.
534	*
535	* Return: The parent maple node.
536	*/
537	static inline struct maple_node mte_parent(const struct maple_enode enode)
538	{
539	return (void *)((unsigned long)
540	(mte_to_node(enode)->parent) & ~MAPLE_NODE_MASK);
541	}
542
543	/*
544	* ma_dead_node() - check if the @enode is dead.
545	* @enode: The encoded maple node
546	*
547	* Return: true if dead, false otherwise.
548	*/
549	static inline bool ma_dead_node(const struct maple_node *node)
550	{
551	struct maple_node *parent;
552
553	/* Do not reorder reads from the node prior to the parent check */
554	smp_rmb();
555	parent = (void *)((unsigned long) node->parent & ~MAPLE_NODE_MASK);
556	return (parent == node);
557	}
558
559	/*
560	* mte_dead_node() - check if the @enode is dead.
561	* @enode: The encoded maple node
562	*
563	* Return: true if dead, false otherwise.
564	*/
565	static inline bool mte_dead_node(const struct maple_enode *enode)
566	{
567	struct maple_node parent, node;
568
569	node = mte_to_node(enode);
570	/* Do not reorder reads from the node prior to the parent check */
571	smp_rmb();
572	parent = mte_parent(enode);
573	return (parent == node);
574	}
575
576	/*
577	* mas_allocated() - Get the number of nodes allocated in a maple state.
578	* @mas: The maple state
579	*
580	* The ma_state alloc member is overloaded to hold a pointer to the first
581	* allocated node or to the number of requested nodes to allocate. If bit 0 is
582	* set, then the alloc contains the number of requested nodes. If there is an
583	* allocated node, then the total allocated nodes is in that node.
584	*
585	* Return: The total number of nodes allocated
586	*/
587	static inline unsigned long mas_allocated(const struct ma_state *mas)
588	{
589	if (!mas->alloc \|\| ((unsigned long)mas->alloc & 0x1))
590	return 0;
591
592	return mas->alloc->total;
593	}
594
595	/*
596	* mas_set_alloc_req() - Set the requested number of allocations.
597	* @mas: the maple state
598	* @count: the number of allocations.
599	*
600	* The requested number of allocations is either in the first allocated node,
601	* located in @mas->alloc->request_count, or directly in @mas->alloc if there is
602	* no allocated node. Set the request either in the node or do the necessary
603	* encoding to store in @mas->alloc directly.
604	*/
605	static inline void mas_set_alloc_req(struct ma_state *mas, unsigned long count)
606	{
607	if (!mas->alloc \|\| ((unsigned long)mas->alloc & 0x1)) {
608	if (!count)
609	mas->alloc = NULL;
610	else
611	mas->alloc = (struct maple_alloc *)(((count) << 1U) \| 1U);
612	return;
613	}
614
615	mas->alloc->request_count = count;
616	}
617
618	/*
619	* mas_alloc_req() - get the requested number of allocations.
620	* @mas: The maple state
621	*
622	* The alloc count is either stored directly in @mas, or in
623	* @mas->alloc->request_count if there is at least one node allocated. Decode
624	* the request count if it's stored directly in @mas->alloc.
625	*
626	* Return: The allocation request count.
627	*/
628	static inline unsigned int mas_alloc_req(const struct ma_state *mas)
629	{
630	if ((unsigned long)mas->alloc & 0x1)
631	return (unsigned long)(mas->alloc) >> 1;
632	else if (mas->alloc)
633	return mas->alloc->request_count;
634	return 0;
635	}
636
637	/*
638	* ma_pivots() - Get a pointer to the maple node pivots.
639	* @node - the maple node
640	* @type - the node type
641	*
642	* In the event of a dead node, this array may be %NULL
643	*
644	* Return: A pointer to the maple node pivots
645	*/
646	static inline unsigned long ma_pivots(struct maple_node node,
647	enum maple_type type)
648	{
649	switch (type) {
650	case maple_arange_64:
651	return node->ma64.pivot;
652	case maple_range_64:
653	case maple_leaf_64:
654	return node->mr64.pivot;
655	case maple_dense:
656	return NULL;
657	}
658	return NULL;
659	}
660
661	/*
662	* ma_gaps() - Get a pointer to the maple node gaps.
663	* @node - the maple node
664	* @type - the node type
665	*
666	* Return: A pointer to the maple node gaps
667	*/
668	static inline unsigned long ma_gaps(struct maple_node node,
669	enum maple_type type)
670	{
671	switch (type) {
672	case maple_arange_64:
673	return node->ma64.gap;
674	case maple_range_64:
675	case maple_leaf_64:
676	case maple_dense:
677	return NULL;
678	}
679	return NULL;
680	}
681
682	/*
683	* mas_pivot() - Get the pivot at @piv of the maple encoded node.
684	* @mas: The maple state.
685	* @piv: The pivot.
686	*
687	* Return: the pivot at @piv of @mn.
688	*/
689	static inline unsigned long mas_pivot(struct ma_state *mas, unsigned char piv)
690	{
691	struct maple_node *node = mas_mn(mas);
692	enum maple_type type = mte_node_type(mas->node);
693
694	if (MAS_WARN_ON(mas, piv >= mt_pivots[type])) {
695	mas_set_err(mas, -EIO);
696	return 0;
697	}
698
699	switch (type) {
700	case maple_arange_64:
701	return node->ma64.pivot[piv];
702	case maple_range_64:
703	case maple_leaf_64:
704	return node->mr64.pivot[piv];
705	case maple_dense:
706	return 0;
707	}
708	return 0;
709	}
710
711	/*
712	* mas_safe_pivot() - get the pivot at @piv or mas->max.
713	* @mas: The maple state
714	* @pivots: The pointer to the maple node pivots
715	* @piv: The pivot to fetch
716	* @type: The maple node type
717	*
718	* Return: The pivot at @piv within the limit of the @pivots array, @mas->max
719	* otherwise.
720	*/
721	static inline unsigned long
722	mas_safe_pivot(const struct ma_state mas, unsigned long pivots,
723	unsigned char piv, enum maple_type type)
724	{
725	if (piv >= mt_pivots[type])
726	return mas->max;
727
728	return pivots[piv];
729	}
730
731	/*
732	* mas_safe_min() - Return the minimum for a given offset.
733	* @mas: The maple state
734	* @pivots: The pointer to the maple node pivots
735	* @offset: The offset into the pivot array
736	*
737	* Return: The minimum range value that is contained in @offset.
738	*/
739	static inline unsigned long
740	mas_safe_min(struct ma_state mas, unsigned long pivots, unsigned char offset)
741	{
742	if (likely(offset))
743	return pivots[offset - 1] + 1;
744
745	return mas->min;
746	}
747
748	/*
749	* mte_set_pivot() - Set a pivot to a value in an encoded maple node.
750	* @mn: The encoded maple node
751	* @piv: The pivot offset
752	* @val: The value of the pivot
753	*/
754	static inline void mte_set_pivot(struct maple_enode *mn, unsigned char piv,
755	unsigned long val)
756	{
757	struct maple_node *node = mte_to_node(mn);
758	enum maple_type type = mte_node_type(mn);
759
760	BUG_ON(piv >= mt_pivots[type]);
761	switch (type) {
762	default:
763	case maple_range_64:
764	case maple_leaf_64:
765	node->mr64.pivot[piv] = val;
766	break;
767	case maple_arange_64:
768	node->ma64.pivot[piv] = val;
769	break;
770	case maple_dense:
771	break;
772	}
773
774	}
775
776	/*
777	* ma_slots() - Get a pointer to the maple node slots.
778	* @mn: The maple node
779	* @mt: The maple node type
780	*
781	* Return: A pointer to the maple node slots
782	*/
783	static inline void __rcu *ma_slots(struct maple_node mn, enum maple_type mt)
784	{
785	switch (mt) {
786	default:
787	case maple_arange_64:
788	return mn->ma64.slot;
789	case maple_range_64:
790	case maple_leaf_64:
791	return mn->mr64.slot;
792	case maple_dense:
793	return mn->slot;
794	}
795	}
796
797	static inline bool mt_write_locked(const struct maple_tree *mt)
798	{
799	return mt_external_lock(mt) ? mt_write_lock_is_held(mt) :
800	lockdep_is_held(&mt->ma_lock);
801	}
802
803	static inline bool mt_locked(const struct maple_tree *mt)
804	{
805	return mt_external_lock(mt) ? mt_lock_is_held(mt) :
806	lockdep_is_held(&mt->ma_lock);
807	}
808
809	static inline void mt_slot(const struct maple_tree mt,
810	void __rcu **slots, unsigned char offset)
811	{
812	return rcu_dereference_check(slots[offset], mt_locked(mt));
813	}
814
815	static inline void mt_slot_locked(struct maple_tree mt, void __rcu **slots,
816	unsigned char offset)
817	{
818	return rcu_dereference_protected(slots[offset], mt_write_locked(mt));
819	}
820	/*
821	* mas_slot_locked() - Get the slot value when holding the maple tree lock.
822	* @mas: The maple state
823	* @slots: The pointer to the slots
824	* @offset: The offset into the slots array to fetch
825	*
826	* Return: The entry stored in @slots at the @offset.
827	*/
828	static inline void mas_slot_locked(struct ma_state mas, void __rcu **slots,
829	unsigned char offset)
830	{
831	return mt_slot_locked(mas->tree, slots, offset);
832	}
833
834	/*
835	* mas_slot() - Get the slot value when not holding the maple tree lock.
836	* @mas: The maple state
837	* @slots: The pointer to the slots
838	* @offset: The offset into the slots array to fetch
839	*
840	* Return: The entry stored in @slots at the @offset
841	*/
842	static inline void mas_slot(struct ma_state mas, void __rcu **slots,
843	unsigned char offset)
844	{
845	return mt_slot(mas->tree, slots, offset);
846	}
847
848	/*
849	* mas_root() - Get the maple tree root.
850	* @mas: The maple state.
851	*
852	* Return: The pointer to the root of the tree
853	*/
854	static inline void mas_root(struct ma_state mas)
855	{
856	return rcu_dereference_check(mas->tree->ma_root, mt_locked(mas->tree));
857	}
858
859	static inline void mt_root_locked(struct maple_tree mt)
860	{
861	return rcu_dereference_protected(mt->ma_root, mt_write_locked(mt));
862	}
863
864	/*
865	* mas_root_locked() - Get the maple tree root when holding the maple tree lock.
866	* @mas: The maple state.
867	*
868	* Return: The pointer to the root of the tree
869	*/
870	static inline void mas_root_locked(struct ma_state mas)
871	{
872	return mt_root_locked(mas->tree);
873	}
874
875	static inline struct maple_metadata ma_meta(struct maple_node mn,
876	enum maple_type mt)
877	{
878	switch (mt) {
879	case maple_arange_64:
880	return &mn->ma64.meta;
881	default:
882	return &mn->mr64.meta;
883	}
884	}
885
886	/*
887	* ma_set_meta() - Set the metadata information of a node.
888	* @mn: The maple node
889	* @mt: The maple node type
890	* @offset: The offset of the highest sub-gap in this node.
891	* @end: The end of the data in this node.
892	*/
893	static inline void ma_set_meta(struct maple_node *mn, enum maple_type mt,
894	unsigned char offset, unsigned char end)
895	{
896	struct maple_metadata *meta = ma_meta(mn, mt);
897
898	meta->gap = offset;
899	meta->end = end;
900	}
901
902	/*
903	* mt_clear_meta() - clear the metadata information of a node, if it exists
904	* @mt: The maple tree
905	* @mn: The maple node
906	* @type: The maple node type
907	* @offset: The offset of the highest sub-gap in this node.
908	* @end: The end of the data in this node.
909	*/
910	static inline void mt_clear_meta(struct maple_tree mt, struct maple_node mn,
911	enum maple_type type)
912	{
913	struct maple_metadata *meta;
914	unsigned long *pivots;
915	void __rcu **slots;
916	void *next;
917
918	switch (type) {
919	case maple_range_64:
920	pivots = mn->mr64.pivot;
921	if (unlikely(pivots[MAPLE_RANGE64_SLOTS - 2])) {
922	slots = mn->mr64.slot;
923	next = mt_slot_locked(mt, slots,
924	MAPLE_RANGE64_SLOTS - 1);
925	if (unlikely((mte_to_node(next) &&
926	mte_node_type(next))))
927	return; /* no metadata, could be node */
928	}
929	fallthrough;
930	case maple_arange_64:
931	meta = ma_meta(mn, type);
932	break;
933	default:
934	return;
935	}
936
937	meta->gap = 0;
938	meta->end = 0;
939	}
940
941	/*
942	* ma_meta_end() - Get the data end of a node from the metadata
943	* @mn: The maple node
944	* @mt: The maple node type
945	*/
946	static inline unsigned char ma_meta_end(struct maple_node *mn,
947	enum maple_type mt)
948	{
949	struct maple_metadata *meta = ma_meta(mn, mt);
950
951	return meta->end;
952	}
953
954	/*
955	* ma_meta_gap() - Get the largest gap location of a node from the metadata
956	* @mn: The maple node
957	* @mt: The maple node type
958	*/
959	static inline unsigned char ma_meta_gap(struct maple_node *mn,
960	enum maple_type mt)
961	{
962	return mn->ma64.meta.gap;
963	}
964
965	/*
966	* ma_set_meta_gap() - Set the largest gap location in a nodes metadata
967	* @mn: The maple node
968	* @mn: The maple node type
969	* @offset: The location of the largest gap.
970	*/
971	static inline void ma_set_meta_gap(struct maple_node *mn, enum maple_type mt,
972	unsigned char offset)
973	{
974
975	struct maple_metadata *meta = ma_meta(mn, mt);
976
977	meta->gap = offset;
978	}
979
980	/*
981	* mat_add() - Add a @dead_enode to the ma_topiary of a list of dead nodes.
982	* @mat - the ma_topiary, a linked list of dead nodes.
983	* @dead_enode - the node to be marked as dead and added to the tail of the list
984	*
985	* Add the @dead_enode to the linked list in @mat.
986	*/
987	static inline void mat_add(struct ma_topiary *mat,
988	struct maple_enode *dead_enode)
989	{
990	mte_set_node_dead(dead_enode);
991	mte_to_mat(dead_enode)->next = NULL;
992	if (!mat->tail) {
993	mat->tail = mat->head = dead_enode;
994	return;
995	}
996
997	mte_to_mat(mat->tail)->next = dead_enode;
998	mat->tail = dead_enode;
999	}
1000
1001	static void mt_free_walk(struct rcu_head *head);
1002	static void mt_destroy_walk(struct maple_enode enode, struct maple_tree mt,
1003	bool free);
1004	/*
1005	* mas_mat_destroy() - Free all nodes and subtrees in a dead list.
1006	* @mas - the maple state
1007	* @mat - the ma_topiary linked list of dead nodes to free.
1008	*
1009	* Destroy walk a dead list.
1010	*/
1011	static void mas_mat_destroy(struct ma_state mas, struct ma_topiary mat)
1012	{
1013	struct maple_enode *next;
1014	struct maple_node *node;
1015	bool in_rcu = mt_in_rcu(mas->tree);
1016
1017	while (mat->head) {
1018	next = mte_to_mat(mat->head)->next;
1019	node = mte_to_node(mat->head);
1020	mt_destroy_walk(mat->head, mas->tree, !in_rcu);
1021	if (in_rcu)
1022	call_rcu(&node->rcu, mt_free_walk);
1023	mat->head = next;
1024	}
1025	}
1026	/*
1027	* mas_descend() - Descend into the slot stored in the ma_state.
1028	* @mas - the maple state.
1029	*
1030	* Note: Not RCU safe, only use in write side or debug code.
1031	*/
1032	static inline void mas_descend(struct ma_state *mas)
1033	{
1034	enum maple_type type;
1035	unsigned long *pivots;
1036	struct maple_node *node;
1037	void __rcu **slots;
1038
1039	node = mas_mn(mas);
1040	type = mte_node_type(mas->node);
1041	pivots = ma_pivots(node, type);
1042	slots = ma_slots(node, type);
1043
1044	if (mas->offset)
1045	mas->min = pivots[mas->offset - 1] + 1;
1046	mas->max = mas_safe_pivot(mas, pivots, mas->offset, type);
1047	mas->node = mas_slot(mas, slots, mas->offset);
1048	}
1049
1050	/*
1051	* mte_set_gap() - Set a maple node gap.
1052	* @mn: The encoded maple node
1053	* @gap: The offset of the gap to set
1054	* @val: The gap value
1055	*/
1056	static inline void mte_set_gap(const struct maple_enode *mn,
1057	unsigned char gap, unsigned long val)
1058	{
1059	switch (mte_node_type(mn)) {
1060	default:
1061	break;
1062	case maple_arange_64:
1063	mte_to_node(mn)->ma64.gap[gap] = val;
1064	break;
1065	}
1066	}
1067
1068	/*
1069	* mas_ascend() - Walk up a level of the tree.
1070	* @mas: The maple state
1071	*
1072	* Sets the @mas->max and @mas->min to the correct values when walking up. This
1073	* may cause several levels of walking up to find the correct min and max.
1074	* May find a dead node which will cause a premature return.
1075	* Return: 1 on dead node, 0 otherwise
1076	*/
1077	static int mas_ascend(struct ma_state *mas)
1078	{
1079	struct maple_enode p_enode; / parent enode. */
1080	struct maple_enode a_enode; / ancestor enode. */
1081	struct maple_node a_node; / ancestor node. */
1082	struct maple_node p_node; / parent node. */
1083	unsigned char a_slot;
1084	enum maple_type a_type;
1085	unsigned long min, max;
1086	unsigned long *pivots;
1087	bool set_max = false, set_min = false;
1088
1089	a_node = mas_mn(mas);
1090	if (ma_is_root(a_node)) {
1091	mas->offset = 0;
1092	return 0;
1093	}
1094
1095	p_node = mte_parent(mas->node);
1096	if (unlikely(a_node == p_node))
1097	return 1;
1098
1099	a_type = mas_parent_type(mas, mas->node);
1100	mas->offset = mte_parent_slot(mas->node);
1101	a_enode = mt_mk_node(p_node, a_type);
1102
1103	/* Check to make sure all parent information is still accurate */
1104	if (p_node != mte_parent(mas->node))
1105	return 1;
1106
1107	mas->node = a_enode;
1108
1109	if (mte_is_root(a_enode)) {
1110	mas->max = ULONG_MAX;
1111	mas->min = 0;
1112	return 0;
1113	}
1114
1115	if (!mas->min)
1116	set_min = true;
1117
1118	if (mas->max == ULONG_MAX)
1119	set_max = true;
1120
1121	min = 0;
1122	max = ULONG_MAX;
1123	do {
1124	p_enode = a_enode;
1125	a_type = mas_parent_type(mas, p_enode);
1126	a_node = mte_parent(p_enode);
1127	a_slot = mte_parent_slot(p_enode);
1128	a_enode = mt_mk_node(a_node, a_type);
1129	pivots = ma_pivots(a_node, a_type);
1130
1131	if (unlikely(ma_dead_node(a_node)))
1132	return 1;
1133
1134	if (!set_min && a_slot) {
1135	set_min = true;
1136	min = pivots[a_slot - 1] + 1;
1137	}
1138
1139	if (!set_max && a_slot < mt_pivots[a_type]) {
1140	set_max = true;
1141	max = pivots[a_slot];
1142	}
1143
1144	if (unlikely(ma_dead_node(a_node)))
1145	return 1;
1146
1147	if (unlikely(ma_is_root(a_node)))
1148	break;
1149
1150	} while (!set_min \|\| !set_max);
1151
1152	mas->max = max;
1153	mas->min = min;
1154	return 0;
1155	}
1156
1157	/*
1158	* mas_pop_node() - Get a previously allocated maple node from the maple state.
1159	* @mas: The maple state
1160	*
1161	* Return: A pointer to a maple node.
1162	*/
1163	static inline struct maple_node mas_pop_node(struct ma_state mas)
1164	{
1165	struct maple_alloc ret, node = mas->alloc;
1166	unsigned long total = mas_allocated(mas);
1167	unsigned int req = mas_alloc_req(mas);
1168
1169	/* nothing or a request pending. */
1170	if (WARN_ON(!total))
1171	return NULL;
1172
1173	if (total == 1) {
1174	/* single allocation in this ma_state */
1175	mas->alloc = NULL;
1176	ret = node;
1177	goto single_node;
1178	}
1179
1180	if (node->node_count == 1) {
1181	/* Single allocation in this node. */
1182	mas->alloc = node->slot[0];
1183	mas->alloc->total = node->total - 1;
1184	ret = node;
1185	goto new_head;
1186	}
1187	node->total--;
1188	ret = node->slot[--node->node_count];
1189	node->slot[node->node_count] = NULL;
1190
1191	single_node:
1192	new_head:
1193	if (req) {
1194	req++;
1195	mas_set_alloc_req(mas, req);
1196	}
1197
1198	memset(ret, 0, sizeof(*ret));
1199	return (struct maple_node *)ret;
1200	}
1201
1202	/*
1203	* mas_push_node() - Push a node back on the maple state allocation.
1204	* @mas: The maple state
1205	* @used: The used maple node
1206	*
1207	* Stores the maple node back into @mas->alloc for reuse. Updates allocated and
1208	* requested node count as necessary.
1209	*/
1210	static inline void mas_push_node(struct ma_state mas, struct maple_node used)
1211	{
1212	struct maple_alloc reuse = (struct maple_alloc )used;
1213	struct maple_alloc *head = mas->alloc;
1214	unsigned long count;
1215	unsigned int requested = mas_alloc_req(mas);
1216
1217	count = mas_allocated(mas);
1218
1219	reuse->request_count = 0;
1220	reuse->node_count = 0;
1221	if (count && (head->node_count < MAPLE_ALLOC_SLOTS)) {
1222	head->slot[head->node_count++] = reuse;
1223	head->total++;
1224	goto done;
1225	}
1226
1227	reuse->total = 1;
1228	if ((head) && !((unsigned long)head & 0x1)) {
1229	reuse->slot[0] = head;
1230	reuse->node_count = 1;
1231	reuse->total += head->total;
1232	}
1233
1234	mas->alloc = reuse;
1235	done:
1236	if (requested > 1)
1237	mas_set_alloc_req(mas, requested - 1);
1238	}
1239
1240	/*
1241	* mas_alloc_nodes() - Allocate nodes into a maple state
1242	* @mas: The maple state
1243	* @gfp: The GFP Flags
1244	*/
1245	static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
1246	{
1247	struct maple_alloc *node;
1248	unsigned long allocated = mas_allocated(mas);
1249	unsigned int requested = mas_alloc_req(mas);
1250	unsigned int count;
1251	void **slots = NULL;
1252	unsigned int max_req = 0;
1253
1254	if (!requested)
1255	return;
1256
1257	mas_set_alloc_req(mas, 0);
1258	if (mas->mas_flags & MA_STATE_PREALLOC) {
1259	if (allocated)
1260	return;
1261	WARN_ON(!allocated);
1262	}
1263
1264	if (!allocated \|\| mas->alloc->node_count == MAPLE_ALLOC_SLOTS) {
1265	node = (struct maple_alloc *)mt_alloc_one(gfp);
1266	if (!node)
1267	goto nomem_one;
1268
1269	if (allocated) {
1270	node->slot[0] = mas->alloc;
1271	node->node_count = 1;
1272	} else {
1273	node->node_count = 0;
1274	}
1275
1276	mas->alloc = node;
1277	node->total = ++allocated;
1278	requested--;
1279	}
1280
1281	node = mas->alloc;
1282	node->request_count = 0;
1283	while (requested) {
1284	max_req = MAPLE_ALLOC_SLOTS - node->node_count;
1285	slots = (void **)&node->slot[node->node_count];
1286	max_req = min(requested, max_req);
1287	count = mt_alloc_bulk(gfp, max_req, slots);
1288	if (!count)
1289	goto nomem_bulk;
1290
1291	if (node->node_count == 0) {
1292	node->slot[0]->node_count = 0;
1293	node->slot[0]->request_count = 0;
1294	}
1295
1296	node->node_count += count;
1297	allocated += count;
1298	node = node->slot[0];
1299	requested -= count;
1300	}
1301	mas->alloc->total = allocated;
1302	return;
1303
1304	nomem_bulk:
1305	/* Clean up potential freed allocations on bulk failure */
1306	memset(slots, 0, max_req * sizeof(unsigned long));
1307	nomem_one:
1308	mas_set_alloc_req(mas, requested);
1309	if (mas->alloc && !(((unsigned long)mas->alloc & 0x1)))
1310	mas->alloc->total = allocated;
1311	mas_set_err(mas, -ENOMEM);
1312	}
1313
1314	/*
1315	* mas_free() - Free an encoded maple node
1316	* @mas: The maple state
1317	* @used: The encoded maple node to free.
1318	*
1319	* Uses rcu free if necessary, pushes @used back on the maple state allocations
1320	* otherwise.
1321	*/
1322	static inline void mas_free(struct ma_state mas, struct maple_enode used)
1323	{
1324	struct maple_node *tmp = mte_to_node(used);
1325
1326	if (mt_in_rcu(mas->tree))
1327	ma_free_rcu(tmp);
1328	else
1329	mas_push_node(mas, tmp);
1330	}
1331
1332	/*
1333	* mas_node_count() - Check if enough nodes are allocated and request more if
1334	* there is not enough nodes.
1335	* @mas: The maple state
1336	* @count: The number of nodes needed
1337	* @gfp: the gfp flags
1338	*/
1339	static void mas_node_count_gfp(struct ma_state *mas, int count, gfp_t gfp)
1340	{
1341	unsigned long allocated = mas_allocated(mas);
1342
1343	if (allocated < count) {
1344	mas_set_alloc_req(mas, count - allocated);
1345	mas_alloc_nodes(mas, gfp);
1346	}
1347	}
1348
1349	/*
1350	* mas_node_count() - Check if enough nodes are allocated and request more if
1351	* there is not enough nodes.
1352	* @mas: The maple state
1353	* @count: The number of nodes needed
1354	*
1355	* Note: Uses GFP_NOWAIT \| __GFP_NOWARN for gfp flags.
1356	*/
1357	static void mas_node_count(struct ma_state *mas, int count)
1358	{
1359	return mas_node_count_gfp(mas, count, GFP_NOWAIT \| __GFP_NOWARN);
1360	}
1361
1362	/*
1363	* mas_start() - Sets up maple state for operations.
1364	* @mas: The maple state.
1365	*
1366	* If mas->node == MAS_START, then set the min, max and depth to
1367	* defaults.
1368	*
1369	* Return:
1370	* - If mas->node is an error or not MAS_START, return NULL.
1371	* - If it's an empty tree: NULL & mas->node == MAS_NONE
1372	* - If it's a single entry: The entry & mas->node == MAS_ROOT
1373	* - If it's a tree: NULL & mas->node == safe root node.
1374	*/
1375	static inline struct maple_enode mas_start(struct ma_state mas)
1376	{
1377	if (likely(mas_is_start(mas))) {
1378	struct maple_enode *root;
1379
1380	mas->min = 0;
1381	mas->max = ULONG_MAX;
1382
1383	retry:
1384	mas->depth = 0;
1385	root = mas_root(mas);
1386	/* Tree with nodes */
1387	if (likely(xa_is_node(root))) {
1388	mas->depth = 1;
1389	mas->node = mte_safe_root(root);
1390	mas->offset = 0;
1391	if (mte_dead_node(mas->node))
1392	goto retry;
1393
1394	return NULL;
1395	}
1396
1397	/* empty tree */
1398	if (unlikely(!root)) {
1399	mas->node = MAS_NONE;
1400	mas->offset = MAPLE_NODE_SLOTS;
1401	return NULL;
1402	}
1403
1404	/* Single entry tree */
1405	mas->node = MAS_ROOT;
1406	mas->offset = MAPLE_NODE_SLOTS;
1407
1408	/* Single entry tree. */
1409	if (mas->index > 0)
1410	return NULL;
1411
1412	return root;
1413	}
1414
1415	return NULL;
1416	}
1417
1418	/*
1419	* ma_data_end() - Find the end of the data in a node.
1420	* @node: The maple node
1421	* @type: The maple node type
1422	* @pivots: The array of pivots in the node
1423	* @max: The maximum value in the node
1424	*
1425	* Uses metadata to find the end of the data when possible.
1426	* Return: The zero indexed last slot with data (may be null).
1427	*/
1428	static inline unsigned char ma_data_end(struct maple_node *node,
1429	enum maple_type type,
1430	unsigned long *pivots,
1431	unsigned long max)
1432	{
1433	unsigned char offset;
1434
1435	if (!pivots)
1436	return 0;
1437
1438	if (type == maple_arange_64)
1439	return ma_meta_end(node, type);
1440
1441	offset = mt_pivots[type] - 1;
1442	if (likely(!pivots[offset]))
1443	return ma_meta_end(node, type);
1444
1445	if (likely(pivots[offset] == max))
1446	return offset;
1447
1448	return mt_pivots[type];
1449	}
1450
1451	/*
1452	* mas_data_end() - Find the end of the data (slot).
1453	* @mas: the maple state
1454	*
1455	* This method is optimized to check the metadata of a node if the node type
1456	* supports data end metadata.
1457	*
1458	* Return: The zero indexed last slot with data (may be null).
1459	*/
1460	static inline unsigned char mas_data_end(struct ma_state *mas)
1461	{
1462	enum maple_type type;
1463	struct maple_node *node;
1464	unsigned char offset;
1465	unsigned long *pivots;
1466
1467	type = mte_node_type(mas->node);
1468	node = mas_mn(mas);
1469	if (type == maple_arange_64)
1470	return ma_meta_end(node, type);
1471
1472	pivots = ma_pivots(node, type);
1473	if (unlikely(ma_dead_node(node)))
1474	return 0;
1475
1476	offset = mt_pivots[type] - 1;
1477	if (likely(!pivots[offset]))
1478	return ma_meta_end(node, type);
1479
1480	if (likely(pivots[offset] == mas->max))
1481	return offset;
1482
1483	return mt_pivots[type];
1484	}
1485
1486	/*
1487	* mas_leaf_max_gap() - Returns the largest gap in a leaf node
1488	* @mas - the maple state
1489	*
1490	* Return: The maximum gap in the leaf.
1491	*/
1492	static unsigned long mas_leaf_max_gap(struct ma_state *mas)
1493	{
1494	enum maple_type mt;
1495	unsigned long pstart, gap, max_gap;
1496	struct maple_node *mn;
1497	unsigned long *pivots;
1498	void __rcu **slots;
1499	unsigned char i;
1500	unsigned char max_piv;
1501
1502	mt = mte_node_type(mas->node);
1503	mn = mas_mn(mas);
1504	slots = ma_slots(mn, mt);
1505	max_gap = 0;
1506	if (unlikely(ma_is_dense(mt))) {
1507	gap = 0;
1508	for (i = 0; i < mt_slots[mt]; i++) {
1509	if (slots[i]) {
1510	if (gap > max_gap)
1511	max_gap = gap;
1512	gap = 0;
1513	} else {
1514	gap++;
1515	}
1516	}
1517	if (gap > max_gap)
1518	max_gap = gap;
1519	return max_gap;
1520	}
1521
1522	/*
1523	* Check the first implied pivot optimizes the loop below and slot 1 may
1524	* be skipped if there is a gap in slot 0.
1525	*/
1526	pivots = ma_pivots(mn, mt);
1527	if (likely(!slots[0])) {
1528	max_gap = pivots[0] - mas->min + 1;
1529	i = 2;
1530	} else {
1531	i = 1;
1532	}
1533
1534	/* reduce max_piv as the special case is checked before the loop */
1535	max_piv = ma_data_end(mn, mt, pivots, mas->max) - 1;
1536	/*
1537	* Check end implied pivot which can only be a gap on the right most
1538	* node.
1539	*/
1540	if (unlikely(mas->max == ULONG_MAX) && !slots[max_piv + 1]) {
1541	gap = ULONG_MAX - pivots[max_piv];
1542	if (gap > max_gap)
1543	max_gap = gap;
1544	}
1545
1546	for (; i <= max_piv; i++) {
1547	/* data == no gap. */
1548	if (likely(slots[i]))
1549	continue;
1550
1551	pstart = pivots[i - 1];
1552	gap = pivots[i] - pstart;
1553	if (gap > max_gap)
1554	max_gap = gap;
1555
1556	/* There cannot be two gaps in a row. */
1557	i++;
1558	}
1559	return max_gap;
1560	}
1561
1562	/*
1563	* ma_max_gap() - Get the maximum gap in a maple node (non-leaf)
1564	* @node: The maple node
1565	* @gaps: The pointer to the gaps
1566	* @mt: The maple node type
1567	* @*off: Pointer to store the offset location of the gap.
1568	*
1569	* Uses the metadata data end to scan backwards across set gaps.
1570	*
1571	* Return: The maximum gap value
1572	*/
1573	static inline unsigned long
1574	ma_max_gap(struct maple_node node, unsigned long gaps, enum maple_type mt,
1575	unsigned char *off)
1576	{
1577	unsigned char offset, i;
1578	unsigned long max_gap = 0;
1579
1580	i = offset = ma_meta_end(node, mt);
1581	do {
1582	if (gaps[i] > max_gap) {
1583	max_gap = gaps[i];
1584	offset = i;
1585	}
1586	} while (i--);
1587
1588	*off = offset;
1589	return max_gap;
1590	}
1591
1592	/*
1593	* mas_max_gap() - find the largest gap in a non-leaf node and set the slot.
1594	* @mas: The maple state.
1595	*
1596	* Return: The gap value.
1597	*/
1598	static inline unsigned long mas_max_gap(struct ma_state *mas)
1599	{
1600	unsigned long *gaps;
1601	unsigned char offset;
1602	enum maple_type mt;
1603	struct maple_node *node;
1604
1605	mt = mte_node_type(mas->node);
1606	if (ma_is_leaf(mt))
1607	return mas_leaf_max_gap(mas);
1608
1609	node = mas_mn(mas);
1610	MAS_BUG_ON(mas, mt != maple_arange_64);
1611	offset = ma_meta_gap(node, mt);
1612	gaps = ma_gaps(node, mt);
1613	return gaps[offset];
1614	}
1615
1616	/*
1617	* mas_parent_gap() - Set the parent gap and any gaps above, as needed
1618	* @mas: The maple state
1619	* @offset: The gap offset in the parent to set
1620	* @new: The new gap value.
1621	*
1622	* Set the parent gap then continue to set the gap upwards, using the metadata
1623	* of the parent to see if it is necessary to check the node above.
1624	*/
1625	static inline void mas_parent_gap(struct ma_state *mas, unsigned char offset,
1626	unsigned long new)
1627	{
1628	unsigned long meta_gap = 0;
1629	struct maple_node *pnode;
1630	struct maple_enode *penode;
1631	unsigned long *pgaps;
1632	unsigned char meta_offset;
1633	enum maple_type pmt;
1634
1635	pnode = mte_parent(mas->node);
1636	pmt = mas_parent_type(mas, mas->node);
1637	penode = mt_mk_node(pnode, pmt);
1638	pgaps = ma_gaps(pnode, pmt);
1639
1640	ascend:
1641	MAS_BUG_ON(mas, pmt != maple_arange_64);
1642	meta_offset = ma_meta_gap(pnode, pmt);
1643	meta_gap = pgaps[meta_offset];
1644
1645	pgaps[offset] = new;
1646
1647	if (meta_gap == new)
1648	return;
1649
1650	if (offset != meta_offset) {
1651	if (meta_gap > new)
1652	return;
1653
1654	ma_set_meta_gap(pnode, pmt, offset);
1655	} else if (new < meta_gap) {
1656	new = ma_max_gap(pnode, pgaps, pmt, &meta_offset);
1657	ma_set_meta_gap(pnode, pmt, meta_offset);
1658	}
1659
1660	if (ma_is_root(pnode))
1661	return;
1662
1663	/* Go to the parent node. */
1664	pnode = mte_parent(penode);
1665	pmt = mas_parent_type(mas, penode);
1666	pgaps = ma_gaps(pnode, pmt);
1667	offset = mte_parent_slot(penode);
1668	penode = mt_mk_node(pnode, pmt);
1669	goto ascend;
1670	}
1671
1672	/*
1673	* mas_update_gap() - Update a nodes gaps and propagate up if necessary.
1674	* @mas - the maple state.
1675	*/
1676	static inline void mas_update_gap(struct ma_state *mas)
1677	{
1678	unsigned char pslot;
1679	unsigned long p_gap;
1680	unsigned long max_gap;
1681
1682	if (!mt_is_alloc(mas->tree))
1683	return;
1684
1685	if (mte_is_root(mas->node))
1686	return;
1687
1688	max_gap = mas_max_gap(mas);
1689
1690	pslot = mte_parent_slot(mas->node);
1691	p_gap = ma_gaps(mte_parent(mas->node),
1692	mas_parent_type(mas, mas->node))[pslot];
1693
1694	if (p_gap != max_gap)
1695	mas_parent_gap(mas, pslot, max_gap);
1696	}
1697
1698	/*
1699	* mas_adopt_children() - Set the parent pointer of all nodes in @parent to
1700	* @parent with the slot encoded.
1701	* @mas - the maple state (for the tree)
1702	* @parent - the maple encoded node containing the children.
1703	*/
1704	static inline void mas_adopt_children(struct ma_state *mas,
1705	struct maple_enode *parent)
1706	{
1707	enum maple_type type = mte_node_type(parent);
1708	struct maple_node *node = mte_to_node(parent);
1709	void __rcu **slots = ma_slots(node, type);
1710	unsigned long *pivots = ma_pivots(node, type);
1711	struct maple_enode *child;
1712	unsigned char offset;
1713
1714	offset = ma_data_end(node, type, pivots, mas->max);
1715	do {
1716	child = mas_slot_locked(mas, slots, offset);
1717	mas_set_parent(mas, child, parent, offset);
1718	} while (offset--);
1719	}
1720
1721	/*
1722	* mas_put_in_tree() - Put a new node in the tree, smp_wmb(), and mark the old
1723	* node as dead.
1724	* @mas - the maple state with the new node
1725	* @old_enode - The old maple encoded node to replace.
1726	*/
1727	static inline void mas_put_in_tree(struct ma_state *mas,
1728	struct maple_enode *old_enode)
1729	__must_hold(mas->tree->ma_lock)
1730	{
1731	unsigned char offset;
1732	void __rcu **slots;
1733
1734	if (mte_is_root(mas->node)) {
1735	mas_mn(mas)->parent = ma_parent_ptr(mas_tree_parent(mas));
1736	rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
1737	mas_set_height(mas);
1738	} else {
1739
1740	offset = mte_parent_slot(mas->node);
1741	slots = ma_slots(mte_parent(mas->node),
1742	mas_parent_type(mas, mas->node));
1743	rcu_assign_pointer(slots[offset], mas->node);
1744	}
1745
1746	mte_set_node_dead(old_enode);
1747	}
1748
1749	/*
1750	* mas_replace_node() - Replace a node by putting it in the tree, marking it
1751	* dead, and freeing it.
1752	* the parent encoding to locate the maple node in the tree.
1753	* @mas - the ma_state with @mas->node pointing to the new node.
1754	* @old_enode - The old maple encoded node.
1755	*/
1756	static inline void mas_replace_node(struct ma_state *mas,
1757	struct maple_enode *old_enode)
1758	__must_hold(mas->tree->ma_lock)
1759	{
1760	mas_put_in_tree(mas, old_enode);
1761	mas_free(mas, old_enode);
1762	}
1763
1764	/*
1765	* mas_find_child() - Find a child who has the parent @mas->node.
1766	* @mas: the maple state with the parent.
1767	* @child: the maple state to store the child.
1768	*/
1769	static inline bool mas_find_child(struct ma_state mas, struct ma_state child)
1770	__must_hold(mas->tree->ma_lock)
1771	{
1772	enum maple_type mt;
1773	unsigned char offset;
1774	unsigned char end;
1775	unsigned long *pivots;
1776	struct maple_enode *entry;
1777	struct maple_node *node;
1778	void __rcu **slots;
1779
1780	mt = mte_node_type(mas->node);
1781	node = mas_mn(mas);
1782	slots = ma_slots(node, mt);
1783	pivots = ma_pivots(node, mt);
1784	end = ma_data_end(node, mt, pivots, mas->max);
1785	for (offset = mas->offset; offset <= end; offset++) {
1786	entry = mas_slot_locked(mas, slots, offset);
1787	if (mte_parent(entry) == node) {
1788	child = mas;
1789	mas->offset = offset + 1;
1790	child->offset = offset;
1791	mas_descend(child);
1792	child->offset = 0;
1793	return true;
1794	}
1795	}
1796	return false;
1797	}
1798
1799	/*
1800	* mab_shift_right() - Shift the data in mab right. Note, does not clean out the
1801	* old data or set b_node->b_end.
1802	* @b_node: the maple_big_node
1803	* @shift: the shift count
1804	*/
1805	static inline void mab_shift_right(struct maple_big_node *b_node,
1806	unsigned char shift)
1807	{
1808	unsigned long size = b_node->b_end * sizeof(unsigned long);
1809
1810	memmove(b_node->pivot + shift, b_node->pivot, size);
1811	memmove(b_node->slot + shift, b_node->slot, size);
1812	if (b_node->type == maple_arange_64)
1813	memmove(b_node->gap + shift, b_node->gap, size);
1814	}
1815
1816	/*
1817	* mab_middle_node() - Check if a middle node is needed (unlikely)
1818	* @b_node: the maple_big_node that contains the data.
1819	* @size: the amount of data in the b_node
1820	* @split: the potential split location
1821	* @slot_count: the size that can be stored in a single node being considered.
1822	*
1823	* Return: true if a middle node is required.
1824	*/
1825	static inline bool mab_middle_node(struct maple_big_node *b_node, int split,
1826	unsigned char slot_count)
1827	{
1828	unsigned char size = b_node->b_end;
1829
1830	if (size >= 2 * slot_count)
1831	return true;
1832
1833	if (!b_node->slot[split] && (size >= 2 * slot_count - 1))
1834	return true;
1835
1836	return false;
1837	}
1838
1839	/*
1840	* mab_no_null_split() - ensure the split doesn't fall on a NULL
1841	* @b_node: the maple_big_node with the data
1842	* @split: the suggested split location
1843	* @slot_count: the number of slots in the node being considered.
1844	*
1845	* Return: the split location.
1846	*/
1847	static inline int mab_no_null_split(struct maple_big_node *b_node,
1848	unsigned char split, unsigned char slot_count)
1849	{
1850	if (!b_node->slot[split]) {
1851	/*
1852	* If the split is less than the max slot && the right side will
1853	* still be sufficient, then increment the split on NULL.
1854	*/
1855	if ((split < slot_count - 1) &&
1856	(b_node->b_end - split) > (mt_min_slots[b_node->type]))
1857	split++;
1858	else
1859	split--;
1860	}
1861	return split;
1862	}
1863
1864	/*
1865	* mab_calc_split() - Calculate the split location and if there needs to be two
1866	* splits.
1867	* @bn: The maple_big_node with the data
1868	* @mid_split: The second split, if required. 0 otherwise.
1869	*
1870	* Return: The first split location. The middle split is set in @mid_split.
1871	*/
1872	static inline int mab_calc_split(struct ma_state *mas,
1873	struct maple_big_node bn, unsigned char mid_split, unsigned long min)
1874	{
1875	unsigned char b_end = bn->b_end;
1876	int split = b_end / 2; /* Assume equal split. */
1877	unsigned char slot_min, slot_count = mt_slots[bn->type];
1878
1879	/*
1880	* To support gap tracking, all NULL entries are kept together and a node cannot
1881	* end on a NULL entry, with the exception of the left-most leaf. The
1882	* limitation means that the split of a node must be checked for this condition
1883	* and be able to put more data in one direction or the other.
1884	*/
1885	if (unlikely((mas->mas_flags & MA_STATE_BULK))) {
1886	*mid_split = 0;
1887	split = b_end - mt_min_slots[bn->type];
1888
1889	if (!ma_is_leaf(bn->type))
1890	return split;
1891
1892	mas->mas_flags \|= MA_STATE_REBALANCE;
1893	if (!bn->slot[split])
1894	split--;
1895	return split;
1896	}
1897
1898	/*
1899	* Although extremely rare, it is possible to enter what is known as the 3-way
1900	* split scenario. The 3-way split comes about by means of a store of a range
1901	* that overwrites the end and beginning of two full nodes. The result is a set
1902	* of entries that cannot be stored in 2 nodes. Sometimes, these two nodes can
1903	* also be located in different parent nodes which are also full. This can
1904	* carry upwards all the way to the root in the worst case.
1905	*/
1906	if (unlikely(mab_middle_node(bn, split, slot_count))) {
1907	split = b_end / 3;
1908	mid_split = split 2;
1909	} else {
1910	slot_min = mt_min_slots[bn->type];
1911
1912	*mid_split = 0;
1913	/*
1914	* Avoid having a range less than the slot count unless it
1915	* causes one node to be deficient.
1916	* NOTE: mt_min_slots is 1 based, b_end and split are zero.
1917	*/
1918	while ((split < slot_count - 1) &&
1919	((bn->pivot[split] - min) < slot_count - 1) &&
1920	(b_end - split > slot_min))
1921	split++;
1922	}
1923
1924	/* Avoid ending a node on a NULL entry */
1925	split = mab_no_null_split(bn, split, slot_count);
1926
1927	if (unlikely(*mid_split))
1928	mid_split = mab_no_null_split(bn, mid_split, slot_count);
1929
1930	return split;
1931	}
1932
1933	/*
1934	* mas_mab_cp() - Copy data from a maple state inclusively to a maple_big_node
1935	* and set @b_node->b_end to the next free slot.
1936	* @mas: The maple state
1937	* @mas_start: The starting slot to copy
1938	* @mas_end: The end slot to copy (inclusively)
1939	* @b_node: The maple_big_node to place the data
1940	* @mab_start: The starting location in maple_big_node to store the data.
1941	*/
1942	static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start,
1943	unsigned char mas_end, struct maple_big_node *b_node,
1944	unsigned char mab_start)
1945	{
1946	enum maple_type mt;
1947	struct maple_node *node;
1948	void __rcu **slots;
1949	unsigned long pivots, gaps;
1950	int i = mas_start, j = mab_start;
1951	unsigned char piv_end;
1952
1953	node = mas_mn(mas);
1954	mt = mte_node_type(mas->node);
1955	pivots = ma_pivots(node, mt);
1956	if (!i) {
1957	b_node->pivot[j] = pivots[i++];
1958	if (unlikely(i > mas_end))
1959	goto complete;
1960	j++;
1961	}
1962
1963	piv_end = min(mas_end, mt_pivots[mt]);
1964	for (; i < piv_end; i++, j++) {
1965	b_node->pivot[j] = pivots[i];
1966	if (unlikely(!b_node->pivot[j]))
1967	break;
1968
1969	if (unlikely(mas->max == b_node->pivot[j]))
1970	goto complete;
1971	}
1972
1973	if (likely(i <= mas_end))
1974	b_node->pivot[j] = mas_safe_pivot(mas, pivots, i, mt);
1975
1976	complete:
1977	b_node->b_end = ++j;
1978	j -= mab_start;
1979	slots = ma_slots(node, mt);
1980	memcpy(b_node->slot + mab_start, slots + mas_start, sizeof(void ) j);
1981	if (!ma_is_leaf(mt) && mt_is_alloc(mas->tree)) {
1982	gaps = ma_gaps(node, mt);
1983	memcpy(b_node->gap + mab_start, gaps + mas_start,
1984	sizeof(unsigned long) * j);
1985	}
1986	}
1987
1988	/*
1989	* mas_leaf_set_meta() - Set the metadata of a leaf if possible.
1990	* @mas: The maple state
1991	* @node: The maple node
1992	* @pivots: pointer to the maple node pivots
1993	* @mt: The maple type
1994	* @end: The assumed end
1995	*
1996	* Note, end may be incremented within this function but not modified at the
1997	* source. This is fine since the metadata is the last thing to be stored in a
1998	* node during a write.
1999	*/
2000	static inline void mas_leaf_set_meta(struct ma_state *mas,
2001	struct maple_node node, unsigned long pivots,
2002	enum maple_type mt, unsigned char end)
2003	{
2004	/* There is no room for metadata already */
2005	if (mt_pivots[mt] <= end)
2006	return;
2007
2008	if (pivots[end] && pivots[end] < mas->max)
2009	end++;
2010
2011	if (end < mt_slots[mt] - 1)
2012	ma_set_meta(node, mt, 0, end);
2013	}
2014
2015	/*
2016	* mab_mas_cp() - Copy data from maple_big_node to a maple encoded node.
2017	* @b_node: the maple_big_node that has the data
2018	* @mab_start: the start location in @b_node.
2019	* @mab_end: The end location in @b_node (inclusively)
2020	* @mas: The maple state with the maple encoded node.
2021	*/
2022	static inline void mab_mas_cp(struct maple_big_node *b_node,
2023	unsigned char mab_start, unsigned char mab_end,
2024	struct ma_state *mas, bool new_max)
2025	{
2026	int i, j = 0;
2027	enum maple_type mt = mte_node_type(mas->node);
2028	struct maple_node *node = mte_to_node(mas->node);
2029	void __rcu **slots = ma_slots(node, mt);
2030	unsigned long *pivots = ma_pivots(node, mt);
2031	unsigned long *gaps = NULL;
2032	unsigned char end;
2033
2034	if (mab_end - mab_start > mt_pivots[mt])
2035	mab_end--;
2036
2037	if (!pivots[mt_pivots[mt] - 1])
2038	slots[mt_pivots[mt]] = NULL;
2039
2040	i = mab_start;
2041	do {
2042	pivots[j++] = b_node->pivot[i++];
2043	} while (i <= mab_end && likely(b_node->pivot[i]));
2044
2045	memcpy(slots, b_node->slot + mab_start,
2046	sizeof(void ) (i - mab_start));
2047
2048	if (new_max)
2049	mas->max = b_node->pivot[i - 1];
2050
2051	end = j - 1;
2052	if (likely(!ma_is_leaf(mt) && mt_is_alloc(mas->tree))) {
2053	unsigned long max_gap = 0;
2054	unsigned char offset = 0;
2055
2056	gaps = ma_gaps(node, mt);
2057	do {
2058	gaps[--j] = b_node->gap[--i];
2059	if (gaps[j] > max_gap) {
2060	offset = j;
2061	max_gap = gaps[j];
2062	}
2063	} while (j);
2064
2065	ma_set_meta(node, mt, offset, end);
2066	} else {
2067	mas_leaf_set_meta(mas, node, pivots, mt, end);
2068	}
2069	}
2070
2071	/*
2072	* mas_bulk_rebalance() - Rebalance the end of a tree after a bulk insert.
2073	* @mas: The maple state
2074	* @end: The maple node end
2075	* @mt: The maple node type
2076	*/
2077	static inline void mas_bulk_rebalance(struct ma_state *mas, unsigned char end,
2078	enum maple_type mt)
2079	{
2080	if (!(mas->mas_flags & MA_STATE_BULK))
2081	return;
2082
2083	if (mte_is_root(mas->node))
2084	return;
2085
2086	if (end > mt_min_slots[mt]) {
2087	mas->mas_flags &= ~MA_STATE_REBALANCE;
2088	return;
2089	}
2090	}
2091
2092	/*
2093	* mas_store_b_node() - Store an @entry into the b_node while also copying the
2094	* data from a maple encoded node.
2095	* @wr_mas: the maple write state
2096	* @b_node: the maple_big_node to fill with data
2097	* @offset_end: the offset to end copying
2098	*
2099	* Return: The actual end of the data stored in @b_node
2100	*/
2101	static noinline_for_kasan void mas_store_b_node(struct ma_wr_state *wr_mas,
2102	struct maple_big_node *b_node, unsigned char offset_end)
2103	{
2104	unsigned char slot;
2105	unsigned char b_end;
2106	/* Possible underflow of piv will wrap back to 0 before use. */
2107	unsigned long piv;
2108	struct ma_state *mas = wr_mas->mas;
2109
2110	b_node->type = wr_mas->type;
2111	b_end = 0;
2112	slot = mas->offset;
2113	if (slot) {
2114	/* Copy start data up to insert. */
2115	mas_mab_cp(mas, 0, slot - 1, b_node, 0);
2116	b_end = b_node->b_end;
2117	piv = b_node->pivot[b_end - 1];
2118	} else
2119	piv = mas->min - 1;
2120
2121	if (piv + 1 < mas->index) {
2122	/* Handle range starting after old range */
2123	b_node->slot[b_end] = wr_mas->content;
2124	if (!wr_mas->content)
2125	b_node->gap[b_end] = mas->index - 1 - piv;
2126	b_node->pivot[b_end++] = mas->index - 1;
2127	}
2128
2129	/* Store the new entry. */
2130	mas->offset = b_end;
2131	b_node->slot[b_end] = wr_mas->entry;
2132	b_node->pivot[b_end] = mas->last;
2133
2134	/* Appended. */
2135	if (mas->last >= mas->max)
2136	goto b_end;
2137
2138	/* Handle new range ending before old range ends */
2139	piv = mas_safe_pivot(mas, wr_mas->pivots, offset_end, wr_mas->type);
2140	if (piv > mas->last) {
2141	if (piv == ULONG_MAX)
2142	mas_bulk_rebalance(mas, b_node->b_end, wr_mas->type);
2143
2144	if (offset_end != slot)
2145	wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
2146	offset_end);
2147
2148	b_node->slot[++b_end] = wr_mas->content;
2149	if (!wr_mas->content)
2150	b_node->gap[b_end] = piv - mas->last + 1;
2151	b_node->pivot[b_end] = piv;
2152	}
2153
2154	slot = offset_end + 1;
2155	if (slot > wr_mas->node_end)
2156	goto b_end;
2157
2158	/* Copy end data to the end of the node. */
2159	mas_mab_cp(mas, slot, wr_mas->node_end + 1, b_node, ++b_end);
2160	b_node->b_end--;
2161	return;
2162
2163	b_end:
2164	b_node->b_end = b_end;
2165	}
2166
2167	/*
2168	* mas_prev_sibling() - Find the previous node with the same parent.
2169	* @mas: the maple state
2170	*
2171	* Return: True if there is a previous sibling, false otherwise.
2172	*/
2173	static inline bool mas_prev_sibling(struct ma_state *mas)
2174	{
2175	unsigned int p_slot = mte_parent_slot(mas->node);
2176
2177	if (mte_is_root(mas->node))
2178	return false;
2179
2180	if (!p_slot)
2181	return false;
2182
2183	mas_ascend(mas);
2184	mas->offset = p_slot - 1;
2185	mas_descend(mas);
2186	return true;
2187	}
2188
2189	/*
2190	* mas_next_sibling() - Find the next node with the same parent.
2191	* @mas: the maple state
2192	*
2193	* Return: true if there is a next sibling, false otherwise.
2194	*/
2195	static inline bool mas_next_sibling(struct ma_state *mas)
2196	{
2197	MA_STATE(parent, mas->tree, mas->index, mas->last);
2198
2199	if (mte_is_root(mas->node))
2200	return false;
2201
2202	parent = *mas;
2203	mas_ascend(&parent);
2204	parent.offset = mte_parent_slot(mas->node) + 1;
2205	if (parent.offset > mas_data_end(&parent))
2206	return false;
2207
2208	*mas = parent;
2209	mas_descend(mas);
2210	return true;
2211	}
2212
2213	/*
2214	* mte_node_or_node() - Return the encoded node or MAS_NONE.
2215	* @enode: The encoded maple node.
2216	*
2217	* Shorthand to avoid setting %NULLs in the tree or maple_subtree_state.
2218	*
2219	* Return: @enode or MAS_NONE
2220	*/
2221	static inline struct maple_enode mte_node_or_none(struct maple_enode enode)
2222	{
2223	if (enode)
2224	return enode;
2225
2226	return ma_enode_ptr(MAS_NONE);
2227	}
2228
2229	/*
2230	* mas_wr_node_walk() - Find the correct offset for the index in the @mas.
2231	* @wr_mas: The maple write state
2232	*
2233	* Uses mas_slot_locked() and does not need to worry about dead nodes.
2234	*/
2235	static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas)
2236	{
2237	struct ma_state *mas = wr_mas->mas;
2238	unsigned char count, offset;
2239
2240	if (unlikely(ma_is_dense(wr_mas->type))) {
2241	wr_mas->r_max = wr_mas->r_min = mas->index;
2242	mas->offset = mas->index = mas->min;
2243	return;
2244	}
2245
2246	wr_mas->node = mas_mn(wr_mas->mas);
2247	wr_mas->pivots = ma_pivots(wr_mas->node, wr_mas->type);
2248	count = wr_mas->node_end = ma_data_end(wr_mas->node, wr_mas->type,
2249	wr_mas->pivots, mas->max);
2250	offset = mas->offset;
2251
2252	while (offset < count && mas->index > wr_mas->pivots[offset])
2253	offset++;
2254
2255	wr_mas->r_max = offset < count ? wr_mas->pivots[offset] : mas->max;
2256	wr_mas->r_min = mas_safe_min(mas, wr_mas->pivots, offset);
2257	wr_mas->offset_end = mas->offset = offset;
2258	}
2259
2260	/*
2261	* mast_rebalance_next() - Rebalance against the next node
2262	* @mast: The maple subtree state
2263	* @old_r: The encoded maple node to the right (next node).
2264	*/
2265	static inline void mast_rebalance_next(struct maple_subtree_state *mast)
2266	{
2267	unsigned char b_end = mast->bn->b_end;
2268
2269	mas_mab_cp(mast->orig_r, 0, mt_slot_count(mast->orig_r->node),
2270	mast->bn, b_end);
2271	mast->orig_r->last = mast->orig_r->max;
2272	}
2273
2274	/*
2275	* mast_rebalance_prev() - Rebalance against the previous node
2276	* @mast: The maple subtree state
2277	* @old_l: The encoded maple node to the left (previous node)
2278	*/
2279	static inline void mast_rebalance_prev(struct maple_subtree_state *mast)
2280	{
2281	unsigned char end = mas_data_end(mast->orig_l) + 1;
2282	unsigned char b_end = mast->bn->b_end;
2283
2284	mab_shift_right(mast->bn, end);
2285	mas_mab_cp(mast->orig_l, 0, end - 1, mast->bn, 0);
2286	mast->l->min = mast->orig_l->min;
2287	mast->orig_l->index = mast->orig_l->min;
2288	mast->bn->b_end = end + b_end;
2289	mast->l->offset += end;
2290	}
2291
2292	/*
2293	* mast_spanning_rebalance() - Rebalance nodes with nearest neighbour favouring
2294	* the node to the right. Checking the nodes to the right then the left at each
2295	* level upwards until root is reached.
2296	* Data is copied into the @mast->bn.
2297	* @mast: The maple_subtree_state.
2298	*/
2299	static inline
2300	bool mast_spanning_rebalance(struct maple_subtree_state *mast)
2301	{
2302	struct ma_state r_tmp = *mast->orig_r;
2303	struct ma_state l_tmp = *mast->orig_l;
2304	unsigned char depth = 0;
2305
2306	r_tmp = *mast->orig_r;
2307	l_tmp = *mast->orig_l;
2308	do {
2309	mas_ascend(mast->orig_r);
2310	mas_ascend(mast->orig_l);
2311	depth++;
2312	if (mast->orig_r->offset < mas_data_end(mast->orig_r)) {
2313	mast->orig_r->offset++;
2314	do {
2315	mas_descend(mast->orig_r);
2316	mast->orig_r->offset = 0;
2317	} while (--depth);
2318
2319	mast_rebalance_next(mast);
2320	*mast->orig_l = l_tmp;
2321	return true;
2322	} else if (mast->orig_l->offset != 0) {
2323	mast->orig_l->offset--;
2324	do {
2325	mas_descend(mast->orig_l);
2326	mast->orig_l->offset =
2327	mas_data_end(mast->orig_l);
2328	} while (--depth);
2329
2330	mast_rebalance_prev(mast);
2331	*mast->orig_r = r_tmp;
2332	return true;
2333	}
2334	} while (!mte_is_root(mast->orig_r->node));
2335
2336	*mast->orig_r = r_tmp;
2337	*mast->orig_l = l_tmp;
2338	return false;
2339	}
2340
2341	/*
2342	* mast_ascend() - Ascend the original left and right maple states.
2343	* @mast: the maple subtree state.
2344	*
2345	* Ascend the original left and right sides. Set the offsets to point to the
2346	* data already in the new tree (@mast->l and @mast->r).
2347	*/
2348	static inline void mast_ascend(struct maple_subtree_state *mast)
2349	{
2350	MA_WR_STATE(wr_mas, mast->orig_r, NULL);
2351	mas_ascend(mast->orig_l);
2352	mas_ascend(mast->orig_r);
2353
2354	mast->orig_r->offset = 0;
2355	mast->orig_r->index = mast->r->max;
2356	/* last should be larger than or equal to index */
2357	if (mast->orig_r->last < mast->orig_r->index)
2358	mast->orig_r->last = mast->orig_r->index;
2359
2360	wr_mas.type = mte_node_type(mast->orig_r->node);
2361	mas_wr_node_walk(&wr_mas);
2362	/* Set up the left side of things */
2363	mast->orig_l->offset = 0;
2364	mast->orig_l->index = mast->l->min;
2365	wr_mas.mas = mast->orig_l;
2366	wr_mas.type = mte_node_type(mast->orig_l->node);
2367	mas_wr_node_walk(&wr_mas);
2368
2369	mast->bn->type = wr_mas.type;
2370	}
2371
2372	/*
2373	* mas_new_ma_node() - Create and return a new maple node. Helper function.
2374	* @mas: the maple state with the allocations.
2375	* @b_node: the maple_big_node with the type encoding.
2376	*
2377	* Use the node type from the maple_big_node to allocate a new node from the
2378	* ma_state. This function exists mainly for code readability.
2379	*
2380	* Return: A new maple encoded node
2381	*/
2382	static inline struct maple_enode
2383	mas_new_ma_node(struct ma_state mas, struct maple_big_node *b_node)
2384	{
2385	return mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), b_node->type);
2386	}
2387
2388	/*
2389	* mas_mab_to_node() - Set up right and middle nodes
2390	*
2391	* @mas: the maple state that contains the allocations.
2392	* @b_node: the node which contains the data.
2393	* @left: The pointer which will have the left node
2394	* @right: The pointer which may have the right node
2395	* @middle: the pointer which may have the middle node (rare)
2396	* @mid_split: the split location for the middle node
2397	*
2398	* Return: the split of left.
2399	*/
2400	static inline unsigned char mas_mab_to_node(struct ma_state *mas,
2401	struct maple_big_node b_node, struct maple_enode *left,
2402	struct maple_enode right, struct maple_enode middle,
2403	unsigned char *mid_split, unsigned long min)
2404	{
2405	unsigned char split = 0;
2406	unsigned char slot_count = mt_slots[b_node->type];
2407
2408	*left = mas_new_ma_node(mas, b_node);
2409	*right = NULL;
2410	*middle = NULL;
2411	*mid_split = 0;
2412
2413	if (b_node->b_end < slot_count) {
2414	split = b_node->b_end;
2415	} else {
2416	split = mab_calc_split(mas, b_node, mid_split, min);
2417	*right = mas_new_ma_node(mas, b_node);
2418	}
2419
2420	if (*mid_split)
2421	*middle = mas_new_ma_node(mas, b_node);
2422
2423	return split;
2424
2425	}
2426
2427	/*
2428	* mab_set_b_end() - Add entry to b_node at b_node->b_end and increment the end
2429	* pointer.
2430	* @b_node - the big node to add the entry
2431	* @mas - the maple state to get the pivot (mas->max)
2432	* @entry - the entry to add, if NULL nothing happens.
2433	*/
2434	static inline void mab_set_b_end(struct maple_big_node *b_node,
2435	struct ma_state *mas,
2436	void *entry)
2437	{
2438	if (!entry)
2439	return;
2440
2441	b_node->slot[b_node->b_end] = entry;
2442	if (mt_is_alloc(mas->tree))
2443	b_node->gap[b_node->b_end] = mas_max_gap(mas);
2444	b_node->pivot[b_node->b_end++] = mas->max;
2445	}
2446
2447	/*
2448	* mas_set_split_parent() - combine_then_separate helper function. Sets the parent
2449	* of @mas->node to either @left or @right, depending on @slot and @split
2450	*
2451	* @mas - the maple state with the node that needs a parent
2452	* @left - possible parent 1
2453	* @right - possible parent 2
2454	* @slot - the slot the mas->node was placed
2455	* @split - the split location between @left and @right
2456	*/
2457	static inline void mas_set_split_parent(struct ma_state *mas,
2458	struct maple_enode *left,
2459	struct maple_enode *right,
2460	unsigned char *slot, unsigned char split)
2461	{
2462	if (mas_is_none(mas))
2463	return;
2464
2465	if ((*slot) <= split)
2466	mas_set_parent(mas, mas->node, left, *slot);
2467	else if (right)
2468	mas_set_parent(mas, mas->node, right, (*slot) - split - 1);
2469
2470	(*slot)++;
2471	}
2472
2473	/*
2474	* mte_mid_split_check() - Check if the next node passes the mid-split
2475	* @**l: Pointer to left encoded maple node.
2476	* @**m: Pointer to middle encoded maple node.
2477	* @**r: Pointer to right encoded maple node.
2478	* @slot: The offset
2479	* @*split: The split location.
2480	* @mid_split: The middle split.
2481	*/
2482	static inline void mte_mid_split_check(struct maple_enode **l,
2483	struct maple_enode **r,
2484	struct maple_enode *right,
2485	unsigned char slot,
2486	unsigned char *split,
2487	unsigned char mid_split)
2488	{
2489	if (*r == right)
2490	return;
2491
2492	if (slot < mid_split)
2493	return;
2494
2495	l = r;
2496	*r = right;
2497	*split = mid_split;
2498	}
2499
2500	/*
2501	* mast_set_split_parents() - Helper function to set three nodes parents. Slot
2502	* is taken from @mast->l.
2503	* @mast - the maple subtree state
2504	* @left - the left node
2505	* @right - the right node
2506	* @split - the split location.
2507	*/
2508	static inline void mast_set_split_parents(struct maple_subtree_state *mast,
2509	struct maple_enode *left,
2510	struct maple_enode *middle,
2511	struct maple_enode *right,
2512	unsigned char split,
2513	unsigned char mid_split)
2514	{
2515	unsigned char slot;
2516	struct maple_enode *l = left;
2517	struct maple_enode *r = right;
2518
2519	if (mas_is_none(mast->l))
2520	return;
2521
2522	if (middle)
2523	r = middle;
2524
2525	slot = mast->l->offset;
2526
2527	mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
2528	mas_set_split_parent(mast->l, l, r, &slot, split);
2529
2530	mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
2531	mas_set_split_parent(mast->m, l, r, &slot, split);
2532
2533	mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
2534	mas_set_split_parent(mast->r, l, r, &slot, split);
2535	}
2536
2537	/*
2538	* mas_topiary_node() - Dispose of a singe node
2539	* @mas: The maple state for pushing nodes
2540	* @enode: The encoded maple node
2541	* @in_rcu: If the tree is in rcu mode
2542	*
2543	* The node will either be RCU freed or pushed back on the maple state.
2544	*/
2545	static inline void mas_topiary_node(struct ma_state *mas,
2546	struct maple_enode *enode, bool in_rcu)
2547	{
2548	struct maple_node *tmp;
2549
2550	if (enode == MAS_NONE)
2551	return;
2552
2553	tmp = mte_to_node(enode);
2554	mte_set_node_dead(enode);
2555	if (in_rcu)
2556	ma_free_rcu(tmp);
2557	else
2558	mas_push_node(mas, tmp);
2559	}
2560
2561	/*
2562	* mas_topiary_replace() - Replace the data with new data, then repair the
2563	* parent links within the new tree. Iterate over the dead sub-tree and collect
2564	* the dead subtrees and topiary the nodes that are no longer of use.
2565	*
2566	* The new tree will have up to three children with the correct parent. Keep
2567	* track of the new entries as they need to be followed to find the next level
2568	* of new entries.
2569	*
2570	* The old tree will have up to three children with the old parent. Keep track
2571	* of the old entries as they may have more nodes below replaced. Nodes within
2572	* [index, last] are dead subtrees, others need to be freed and followed.
2573	*
2574	* @mas: The maple state pointing at the new data
2575	* @old_enode: The maple encoded node being replaced
2576	*
2577	*/
2578	static inline void mas_topiary_replace(struct ma_state *mas,
2579	struct maple_enode *old_enode)
2580	{
2581	struct ma_state tmp[3], tmp_next[3];
2582	MA_TOPIARY(subtrees, mas->tree);
2583	bool in_rcu;
2584	int i, n;
2585
2586	/* Place data in tree & then mark node as old */
2587	mas_put_in_tree(mas, old_enode);
2588
2589	/* Update the parent pointers in the tree */
2590	tmp[0] = *mas;
2591	tmp[0].offset = 0;
2592	tmp[1].node = MAS_NONE;
2593	tmp[2].node = MAS_NONE;
2594	while (!mte_is_leaf(tmp[0].node)) {
2595	n = 0;
2596	for (i = 0; i < 3; i++) {
2597	if (mas_is_none(&tmp[i]))
2598	continue;
2599
2600	while (n < 3) {
2601	if (!mas_find_child(&tmp[i], &tmp_next[n]))
2602	break;
2603	n++;
2604	}
2605
2606	mas_adopt_children(&tmp[i], tmp[i].node);
2607	}
2608
2609	if (MAS_WARN_ON(mas, n == 0))
2610	break;
2611
2612	while (n < 3)
2613	tmp_next[n++].node = MAS_NONE;
2614
2615	for (i = 0; i < 3; i++)
2616	tmp[i] = tmp_next[i];
2617	}
2618
2619	/* Collect the old nodes that need to be discarded */
2620	if (mte_is_leaf(old_enode))
2621	return mas_free(mas, old_enode);
2622
2623	tmp[0] = *mas;
2624	tmp[0].offset = 0;
2625	tmp[0].node = old_enode;
2626	tmp[1].node = MAS_NONE;
2627	tmp[2].node = MAS_NONE;
2628	in_rcu = mt_in_rcu(mas->tree);
2629	do {
2630	n = 0;
2631	for (i = 0; i < 3; i++) {
2632	if (mas_is_none(&tmp[i]))
2633	continue;
2634
2635	while (n < 3) {
2636	if (!mas_find_child(&tmp[i], &tmp_next[n]))
2637	break;
2638
2639	if ((tmp_next[n].min >= tmp_next->index) &&
2640	(tmp_next[n].max <= tmp_next->last)) {
2641	mat_add(&subtrees, tmp_next[n].node);
2642	tmp_next[n].node = MAS_NONE;
2643	} else {
2644	n++;
2645	}
2646	}
2647	}
2648
2649	if (MAS_WARN_ON(mas, n == 0))
2650	break;
2651
2652	while (n < 3)
2653	tmp_next[n++].node = MAS_NONE;
2654
2655	for (i = 0; i < 3; i++) {
2656	mas_topiary_node(mas, tmp[i].node, in_rcu);
2657	tmp[i] = tmp_next[i];
2658	}
2659	} while (!mte_is_leaf(tmp[0].node));
2660
2661	for (i = 0; i < 3; i++)
2662	mas_topiary_node(mas, tmp[i].node, in_rcu);
2663
2664	mas_mat_destroy(mas, &subtrees);
2665	}
2666
2667	/*
2668	* mas_wmb_replace() - Write memory barrier and replace
2669	* @mas: The maple state
2670	* @old: The old maple encoded node that is being replaced.
2671	*
2672	* Updates gap as necessary.
2673	*/
2674	static inline void mas_wmb_replace(struct ma_state *mas,
2675	struct maple_enode *old_enode)
2676	{
2677	/* Insert the new data in the tree */
2678	mas_topiary_replace(mas, old_enode);
2679
2680	if (mte_is_leaf(mas->node))
2681	return;
2682
2683	mas_update_gap(mas);
2684	}
2685
2686	/*
2687	* mast_cp_to_nodes() - Copy data out to nodes.
2688	* @mast: The maple subtree state
2689	* @left: The left encoded maple node
2690	* @middle: The middle encoded maple node
2691	* @right: The right encoded maple node
2692	* @split: The location to split between left and (middle ? middle : right)
2693	* @mid_split: The location to split between middle and right.
2694	*/
2695	static inline void mast_cp_to_nodes(struct maple_subtree_state *mast,
2696	struct maple_enode left, struct maple_enode middle,
2697	struct maple_enode *right, unsigned char split, unsigned char mid_split)
2698	{
2699	bool new_lmax = true;
2700
2701	mast->l->node = mte_node_or_none(left);
2702	mast->m->node = mte_node_or_none(middle);
2703	mast->r->node = mte_node_or_none(right);
2704
2705	mast->l->min = mast->orig_l->min;
2706	if (split == mast->bn->b_end) {
2707	mast->l->max = mast->orig_r->max;
2708	new_lmax = false;
2709	}
2710
2711	mab_mas_cp(mast->bn, 0, split, mast->l, new_lmax);
2712
2713	if (middle) {
2714	mab_mas_cp(mast->bn, 1 + split, mid_split, mast->m, true);
2715	mast->m->min = mast->bn->pivot[split] + 1;
2716	split = mid_split;
2717	}
2718
2719	mast->r->max = mast->orig_r->max;
2720	if (right) {
2721	mab_mas_cp(mast->bn, 1 + split, mast->bn->b_end, mast->r, false);
2722	mast->r->min = mast->bn->pivot[split] + 1;
2723	}
2724	}
2725
2726	/*
2727	* mast_combine_cp_left - Copy in the original left side of the tree into the
2728	* combined data set in the maple subtree state big node.
2729	* @mast: The maple subtree state
2730	*/
2731	static inline void mast_combine_cp_left(struct maple_subtree_state *mast)
2732	{
2733	unsigned char l_slot = mast->orig_l->offset;
2734
2735	if (!l_slot)
2736	return;
2737
2738	mas_mab_cp(mast->orig_l, 0, l_slot - 1, mast->bn, 0);
2739	}
2740
2741	/*
2742	* mast_combine_cp_right: Copy in the original right side of the tree into the
2743	* combined data set in the maple subtree state big node.
2744	* @mast: The maple subtree state
2745	*/
2746	static inline void mast_combine_cp_right(struct maple_subtree_state *mast)
2747	{
2748	if (mast->bn->pivot[mast->bn->b_end - 1] >= mast->orig_r->max)
2749	return;
2750
2751	mas_mab_cp(mast->orig_r, mast->orig_r->offset + 1,
2752	mt_slot_count(mast->orig_r->node), mast->bn,
2753	mast->bn->b_end);
2754	mast->orig_r->last = mast->orig_r->max;
2755	}
2756
2757	/*
2758	* mast_sufficient: Check if the maple subtree state has enough data in the big
2759	* node to create at least one sufficient node
2760	* @mast: the maple subtree state
2761	*/
2762	static inline bool mast_sufficient(struct maple_subtree_state *mast)
2763	{
2764	if (mast->bn->b_end > mt_min_slot_count(mast->orig_l->node))
2765	return true;
2766
2767	return false;
2768	}
2769
2770	/*
2771	* mast_overflow: Check if there is too much data in the subtree state for a
2772	* single node.
2773	* @mast: The maple subtree state
2774	*/
2775	static inline bool mast_overflow(struct maple_subtree_state *mast)
2776	{
2777	if (mast->bn->b_end >= mt_slot_count(mast->orig_l->node))
2778	return true;
2779
2780	return false;
2781	}
2782
2783	static inline void mtree_range_walk(struct ma_state mas)
2784	{
2785	unsigned long *pivots;
2786	unsigned char offset;
2787	struct maple_node *node;
2788	struct maple_enode next, last;
2789	enum maple_type type;
2790	void __rcu **slots;
2791	unsigned char end;
2792	unsigned long max, min;
2793	unsigned long prev_max, prev_min;
2794
2795	next = mas->node;
2796	min = mas->min;
2797	max = mas->max;
2798	do {
2799	offset = 0;
2800	last = next;
2801	node = mte_to_node(next);
2802	type = mte_node_type(next);
2803	pivots = ma_pivots(node, type);
2804	end = ma_data_end(node, type, pivots, max);
2805	if (unlikely(ma_dead_node(node)))
2806	goto dead_node;
2807
2808	if (pivots[offset] >= mas->index) {
2809	prev_max = max;
2810	prev_min = min;
2811	max = pivots[offset];
2812	goto next;
2813	}
2814
2815	do {
2816	offset++;
2817	} while ((offset < end) && (pivots[offset] < mas->index));
2818
2819	prev_min = min;
2820	min = pivots[offset - 1] + 1;
2821	prev_max = max;
2822	if (likely(offset < end && pivots[offset]))
2823	max = pivots[offset];
2824
2825	next:
2826	slots = ma_slots(node, type);
2827	next = mt_slot(mas->tree, slots, offset);
2828	if (unlikely(ma_dead_node(node)))
2829	goto dead_node;
2830	} while (!ma_is_leaf(type));
2831
2832	mas->offset = offset;
2833	mas->index = min;
2834	mas->last = max;
2835	mas->min = prev_min;
2836	mas->max = prev_max;
2837	mas->node = last;
2838	return (void *)next;
2839
2840	dead_node:
2841	mas_reset(mas);
2842	return NULL;
2843	}
2844
2845	/*
2846	* mas_spanning_rebalance() - Rebalance across two nodes which may not be peers.
2847	* @mas: The starting maple state
2848	* @mast: The maple_subtree_state, keeps track of 4 maple states.
2849	* @count: The estimated count of iterations needed.
2850	*
2851	* Follow the tree upwards from @l_mas and @r_mas for @count, or until the root
2852	* is hit. First @b_node is split into two entries which are inserted into the
2853	* next iteration of the loop. @b_node is returned populated with the final
2854	* iteration. @mas is used to obtain allocations. orig_l_mas keeps track of the
2855	* nodes that will remain active by using orig_l_mas->index and orig_l_mas->last
2856	* to account of what has been copied into the new sub-tree. The update of
2857	* orig_l_mas->last is used in mas_consume to find the slots that will need to
2858	* be either freed or destroyed. orig_l_mas->depth keeps track of the height of
2859	* the new sub-tree in case the sub-tree becomes the full tree.
2860	*
2861	* Return: the number of elements in b_node during the last loop.
2862	*/
2863	static int mas_spanning_rebalance(struct ma_state *mas,
2864	struct maple_subtree_state *mast, unsigned char count)
2865	{
2866	unsigned char split, mid_split;
2867	unsigned char slot = 0;
2868	struct maple_enode left = NULL, middle = NULL, *right = NULL;
2869	struct maple_enode *old_enode;
2870
2871	MA_STATE(l_mas, mas->tree, mas->index, mas->index);
2872	MA_STATE(r_mas, mas->tree, mas->index, mas->last);
2873	MA_STATE(m_mas, mas->tree, mas->index, mas->index);
2874
2875	/*
2876	* The tree needs to be rebalanced and leaves need to be kept at the same level.
2877	* Rebalancing is done by use of the ``struct maple_topiary``.
2878	*/
2879	mast->l = &l_mas;
2880	mast->m = &m_mas;
2881	mast->r = &r_mas;
2882	l_mas.node = r_mas.node = m_mas.node = MAS_NONE;
2883
2884	/* Check if this is not root and has sufficient data. */
2885	if (((mast->orig_l->min != 0) \|\| (mast->orig_r->max != ULONG_MAX)) &&
2886	unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type]))
2887	mast_spanning_rebalance(mast);
2888
2889	l_mas.depth = 0;
2890
2891	/*
2892	* Each level of the tree is examined and balanced, pushing data to the left or
2893	* right, or rebalancing against left or right nodes is employed to avoid
2894	* rippling up the tree to limit the amount of churn. Once a new sub-section of
2895	* the tree is created, there may be a mix of new and old nodes. The old nodes
2896	* will have the incorrect parent pointers and currently be in two trees: the
2897	* original tree and the partially new tree. To remedy the parent pointers in
2898	* the old tree, the new data is swapped into the active tree and a walk down
2899	* the tree is performed and the parent pointers are updated.
2900	* See mas_topiary_replace() for more information.
2901	*/
2902	while (count--) {
2903	mast->bn->b_end--;
2904	mast->bn->type = mte_node_type(mast->orig_l->node);
2905	split = mas_mab_to_node(mas, mast->bn, &left, &right, &middle,
2906	&mid_split, mast->orig_l->min);
2907	mast_set_split_parents(mast, left, middle, right, split,
2908	mid_split);
2909	mast_cp_to_nodes(mast, left, middle, right, split, mid_split);
2910
2911	/*
2912	* Copy data from next level in the tree to mast->bn from next
2913	* iteration
2914	*/
2915	memset(mast->bn, 0, sizeof(struct maple_big_node));
2916	mast->bn->type = mte_node_type(left);
2917	l_mas.depth++;
2918
2919	/* Root already stored in l->node. */
2920	if (mas_is_root_limits(mast->l))
2921	goto new_root;
2922
2923	mast_ascend(mast);
2924	mast_combine_cp_left(mast);
2925	l_mas.offset = mast->bn->b_end;
2926	mab_set_b_end(mast->bn, &l_mas, left);
2927	mab_set_b_end(mast->bn, &m_mas, middle);
2928	mab_set_b_end(mast->bn, &r_mas, right);
2929
2930	/* Copy anything necessary out of the right node. */
2931	mast_combine_cp_right(mast);
2932	mast->orig_l->last = mast->orig_l->max;
2933
2934	if (mast_sufficient(mast))
2935	continue;
2936
2937	if (mast_overflow(mast))
2938	continue;
2939
2940	/* May be a new root stored in mast->bn */
2941	if (mas_is_root_limits(mast->orig_l))
2942	break;
2943
2944	mast_spanning_rebalance(mast);
2945
2946	/* rebalancing from other nodes may require another loop. */
2947	if (!count)
2948	count++;
2949	}
2950
2951	l_mas.node = mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)),
2952	mte_node_type(mast->orig_l->node));
2953	l_mas.depth++;
2954	mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, &l_mas, true);
2955	mas_set_parent(mas, left, l_mas.node, slot);
2956	if (middle)
2957	mas_set_parent(mas, middle, l_mas.node, ++slot);
2958
2959	if (right)
2960	mas_set_parent(mas, right, l_mas.node, ++slot);
2961
2962	if (mas_is_root_limits(mast->l)) {
2963	new_root:
2964	mas_mn(mast->l)->parent = ma_parent_ptr(mas_tree_parent(mas));
2965	while (!mte_is_root(mast->orig_l->node))
2966	mast_ascend(mast);
2967	} else {
2968	mas_mn(&l_mas)->parent = mas_mn(mast->orig_l)->parent;
2969	}
2970
2971	old_enode = mast->orig_l->node;
2972	mas->depth = l_mas.depth;
2973	mas->node = l_mas.node;
2974	mas->min = l_mas.min;
2975	mas->max = l_mas.max;
2976	mas->offset = l_mas.offset;
2977	mas_wmb_replace(mas, old_enode);
2978	mtree_range_walk(mas);
2979	return mast->bn->b_end;
2980	}
2981
2982	/*
2983	* mas_rebalance() - Rebalance a given node.
2984	* @mas: The maple state
2985	* @b_node: The big maple node.
2986	*
2987	* Rebalance two nodes into a single node or two new nodes that are sufficient.
2988	* Continue upwards until tree is sufficient.
2989	*
2990	* Return: the number of elements in b_node during the last loop.
2991	*/
2992	static inline int mas_rebalance(struct ma_state *mas,
2993	struct maple_big_node *b_node)
2994	{
2995	char empty_count = mas_mt_height(mas);
2996	struct maple_subtree_state mast;
2997	unsigned char shift, b_end = ++b_node->b_end;
2998
2999	MA_STATE(l_mas, mas->tree, mas->index, mas->last);
3000	MA_STATE(r_mas, mas->tree, mas->index, mas->last);
3001
3002	trace_ma_op(__func__, mas);
3003
3004	/*
3005	* Rebalancing occurs if a node is insufficient. Data is rebalanced
3006	* against the node to the right if it exists, otherwise the node to the
3007	* left of this node is rebalanced against this node. If rebalancing
3008	* causes just one node to be produced instead of two, then the parent
3009	* is also examined and rebalanced if it is insufficient. Every level
3010	* tries to combine the data in the same way. If one node contains the
3011	* entire range of the tree, then that node is used as a new root node.
3012	*/
3013	mas_node_count(mas, empty_count * 2 - 1);
3014	if (mas_is_err(mas))
3015	return 0;
3016
3017	mast.orig_l = &l_mas;
3018	mast.orig_r = &r_mas;
3019	mast.bn = b_node;
3020	mast.bn->type = mte_node_type(mas->node);
3021
3022	l_mas = r_mas = *mas;
3023
3024	if (mas_next_sibling(&r_mas)) {
3025	mas_mab_cp(&r_mas, 0, mt_slot_count(r_mas.node), b_node, b_end);
3026	r_mas.last = r_mas.index = r_mas.max;
3027	} else {
3028	mas_prev_sibling(&l_mas);
3029	shift = mas_data_end(&l_mas) + 1;
3030	mab_shift_right(b_node, shift);
3031	mas->offset += shift;
3032	mas_mab_cp(&l_mas, 0, shift - 1, b_node, 0);
3033	b_node->b_end = shift + b_end;
3034	l_mas.index = l_mas.last = l_mas.min;
3035	}
3036
3037	return mas_spanning_rebalance(mas, &mast, empty_count);
3038	}
3039
3040	/*
3041	* mas_destroy_rebalance() - Rebalance left-most node while destroying the maple
3042	* state.
3043	* @mas: The maple state
3044	* @end: The end of the left-most node.
3045	*
3046	* During a mass-insert event (such as forking), it may be necessary to
3047	* rebalance the left-most node when it is not sufficient.
3048	*/
3049	static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end)
3050	{
3051	enum maple_type mt = mte_node_type(mas->node);
3052	struct maple_node reuse, newnode, parent, new_left, left, *node;
3053	struct maple_enode eparent, old_eparent;
3054	unsigned char offset, tmp, split = mt_slots[mt] / 2;
3055	void __rcu l_slots, slots;
3056	unsigned long l_pivs, pivs, gap;
3057	bool in_rcu = mt_in_rcu(mas->tree);
3058
3059	MA_STATE(l_mas, mas->tree, mas->index, mas->last);
3060
3061	l_mas = *mas;
3062	mas_prev_sibling(&l_mas);
3063
3064	/* set up node. */
3065	if (in_rcu) {
3066	/* Allocate for both left and right as well as parent. */
3067	mas_node_count(mas, 3);
3068	if (mas_is_err(mas))
3069	return;
3070
3071	newnode = mas_pop_node(mas);
3072	} else {
3073	newnode = &reuse;
3074	}
3075
3076	node = mas_mn(mas);
3077	newnode->parent = node->parent;
3078	slots = ma_slots(newnode, mt);
3079	pivs = ma_pivots(newnode, mt);
3080	left = mas_mn(&l_mas);
3081	l_slots = ma_slots(left, mt);
3082	l_pivs = ma_pivots(left, mt);
3083	if (!l_slots[split])
3084	split++;
3085	tmp = mas_data_end(&l_mas) - split;
3086
3087	memcpy(slots, l_slots + split + 1, sizeof(void ) tmp);
3088	memcpy(pivs, l_pivs + split + 1, sizeof(unsigned long) * tmp);
3089	pivs[tmp] = l_mas.max;
3090	memcpy(slots + tmp, ma_slots(node, mt), sizeof(void ) end);
3091	memcpy(pivs + tmp, ma_pivots(node, mt), sizeof(unsigned long) * end);
3092
3093	l_mas.max = l_pivs[split];
3094	mas->min = l_mas.max + 1;
3095	old_eparent = mt_mk_node(mte_parent(l_mas.node),
3096	mas_parent_type(&l_mas, l_mas.node));
3097	tmp += end;
3098	if (!in_rcu) {
3099	unsigned char max_p = mt_pivots[mt];
3100	unsigned char max_s = mt_slots[mt];
3101
3102	if (tmp < max_p)
3103	memset(pivs + tmp, 0,
3104	sizeof(unsigned long) * (max_p - tmp));
3105
3106	if (tmp < mt_slots[mt])
3107	memset(slots + tmp, 0, sizeof(void ) (max_s - tmp));
3108
3109	memcpy(node, newnode, sizeof(struct maple_node));
3110	ma_set_meta(node, mt, 0, tmp - 1);
3111	mte_set_pivot(old_eparent, mte_parent_slot(l_mas.node),
3112	l_pivs[split]);
3113
3114	/* Remove data from l_pivs. */
3115	tmp = split + 1;
3116	memset(l_pivs + tmp, 0, sizeof(unsigned long) * (max_p - tmp));
3117	memset(l_slots + tmp, 0, sizeof(void ) (max_s - tmp));
3118	ma_set_meta(left, mt, 0, split);
3119	eparent = old_eparent;
3120
3121	goto done;
3122	}
3123
3124	/* RCU requires replacing both l_mas, mas, and parent. */
3125	mas->node = mt_mk_node(newnode, mt);
3126	ma_set_meta(newnode, mt, 0, tmp);
3127
3128	new_left = mas_pop_node(mas);
3129	new_left->parent = left->parent;
3130	mt = mte_node_type(l_mas.node);
3131	slots = ma_slots(new_left, mt);
3132	pivs = ma_pivots(new_left, mt);
3133	memcpy(slots, l_slots, sizeof(void ) split);
3134	memcpy(pivs, l_pivs, sizeof(unsigned long) * split);
3135	ma_set_meta(new_left, mt, 0, split);
3136	l_mas.node = mt_mk_node(new_left, mt);
3137
3138	/* replace parent. */
3139	offset = mte_parent_slot(mas->node);
3140	mt = mas_parent_type(&l_mas, l_mas.node);
3141	parent = mas_pop_node(mas);
3142	slots = ma_slots(parent, mt);
3143	pivs = ma_pivots(parent, mt);
3144	memcpy(parent, mte_to_node(old_eparent), sizeof(struct maple_node));
3145	rcu_assign_pointer(slots[offset], mas->node);
3146	rcu_assign_pointer(slots[offset - 1], l_mas.node);
3147	pivs[offset - 1] = l_mas.max;
3148	eparent = mt_mk_node(parent, mt);
3149	done:
3150	gap = mas_leaf_max_gap(mas);
3151	mte_set_gap(eparent, mte_parent_slot(mas->node), gap);
3152	gap = mas_leaf_max_gap(&l_mas);
3153	mte_set_gap(eparent, mte_parent_slot(l_mas.node), gap);
3154	mas_ascend(mas);
3155
3156	if (in_rcu) {
3157	mas_replace_node(mas, old_eparent);
3158	mas_adopt_children(mas, mas->node);
3159	}
3160
3161	mas_update_gap(mas);
3162	}
3163
3164	/*
3165	* mas_split_final_node() - Split the final node in a subtree operation.
3166	* @mast: the maple subtree state
3167	* @mas: The maple state
3168	* @height: The height of the tree in case it's a new root.
3169	*/
3170	static inline bool mas_split_final_node(struct maple_subtree_state *mast,
3171	struct ma_state *mas, int height)
3172	{
3173	struct maple_enode *ancestor;
3174
3175	if (mte_is_root(mas->node)) {
3176	if (mt_is_alloc(mas->tree))
3177	mast->bn->type = maple_arange_64;
3178	else
3179	mast->bn->type = maple_range_64;
3180	mas->depth = height;
3181	}
3182	/*
3183	* Only a single node is used here, could be root.
3184	* The Big_node data should just fit in a single node.
3185	*/
3186	ancestor = mas_new_ma_node(mas, mast->bn);
3187	mas_set_parent(mas, mast->l->node, ancestor, mast->l->offset);
3188	mas_set_parent(mas, mast->r->node, ancestor, mast->r->offset);
3189	mte_to_node(ancestor)->parent = mas_mn(mas)->parent;
3190
3191	mast->l->node = ancestor;
3192	mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, mast->l, true);
3193	mas->offset = mast->bn->b_end - 1;
3194	return true;
3195	}
3196
3197	/*
3198	* mast_fill_bnode() - Copy data into the big node in the subtree state
3199	* @mast: The maple subtree state
3200	* @mas: the maple state
3201	* @skip: The number of entries to skip for new nodes insertion.
3202	*/
3203	static inline void mast_fill_bnode(struct maple_subtree_state *mast,
3204	struct ma_state *mas,
3205	unsigned char skip)
3206	{
3207	bool cp = true;
3208	unsigned char split;
3209
3210	memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap));
3211	memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot));
3212	memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot));
3213	mast->bn->b_end = 0;
3214
3215	if (mte_is_root(mas->node)) {
3216	cp = false;
3217	} else {
3218	mas_ascend(mas);
3219	mas->offset = mte_parent_slot(mas->node);
3220	}
3221
3222	if (cp && mast->l->offset)
3223	mas_mab_cp(mas, 0, mast->l->offset - 1, mast->bn, 0);
3224
3225	split = mast->bn->b_end;
3226	mab_set_b_end(mast->bn, mast->l, mast->l->node);
3227	mast->r->offset = mast->bn->b_end;
3228	mab_set_b_end(mast->bn, mast->r, mast->r->node);
3229	if (mast->bn->pivot[mast->bn->b_end - 1] == mas->max)
3230	cp = false;
3231
3232	if (cp)
3233	mas_mab_cp(mas, split + skip, mt_slot_count(mas->node) - 1,
3234	mast->bn, mast->bn->b_end);
3235
3236	mast->bn->b_end--;
3237	mast->bn->type = mte_node_type(mas->node);
3238	}
3239
3240	/*
3241	* mast_split_data() - Split the data in the subtree state big node into regular
3242	* nodes.
3243	* @mast: The maple subtree state
3244	* @mas: The maple state
3245	* @split: The location to split the big node
3246	*/
3247	static inline void mast_split_data(struct maple_subtree_state *mast,
3248	struct ma_state *mas, unsigned char split)
3249	{
3250	unsigned char p_slot;
3251
3252	mab_mas_cp(mast->bn, 0, split, mast->l, true);
3253	mte_set_pivot(mast->r->node, 0, mast->r->max);
3254	mab_mas_cp(mast->bn, split + 1, mast->bn->b_end, mast->r, false);
3255	mast->l->offset = mte_parent_slot(mas->node);
3256	mast->l->max = mast->bn->pivot[split];
3257	mast->r->min = mast->l->max + 1;
3258	if (mte_is_leaf(mas->node))
3259	return;
3260
3261	p_slot = mast->orig_l->offset;
3262	mas_set_split_parent(mast->orig_l, mast->l->node, mast->r->node,
3263	&p_slot, split);
3264	mas_set_split_parent(mast->orig_r, mast->l->node, mast->r->node,
3265	&p_slot, split);
3266	}
3267
3268	/*
3269	* mas_push_data() - Instead of splitting a node, it is beneficial to push the
3270	* data to the right or left node if there is room.
3271	* @mas: The maple state
3272	* @height: The current height of the maple state
3273	* @mast: The maple subtree state
3274	* @left: Push left or not.
3275	*
3276	* Keeping the height of the tree low means faster lookups.
3277	*
3278	* Return: True if pushed, false otherwise.
3279	*/
3280	static inline bool mas_push_data(struct ma_state *mas, int height,
3281	struct maple_subtree_state *mast, bool left)
3282	{
3283	unsigned char slot_total = mast->bn->b_end;
3284	unsigned char end, space, split;
3285
3286	MA_STATE(tmp_mas, mas->tree, mas->index, mas->last);
3287	tmp_mas = *mas;
3288	tmp_mas.depth = mast->l->depth;
3289
3290	if (left && !mas_prev_sibling(&tmp_mas))
3291	return false;
3292	else if (!left && !mas_next_sibling(&tmp_mas))
3293	return false;
3294
3295	end = mas_data_end(&tmp_mas);
3296	slot_total += end;
3297	space = 2 * mt_slot_count(mas->node) - 2;
3298	/* -2 instead of -1 to ensure there isn't a triple split */
3299	if (ma_is_leaf(mast->bn->type))
3300	space--;
3301
3302	if (mas->max == ULONG_MAX)
3303	space--;
3304
3305	if (slot_total >= space)
3306	return false;
3307
3308	/* Get the data; Fill mast->bn */
3309	mast->bn->b_end++;
3310	if (left) {
3311	mab_shift_right(mast->bn, end + 1);
3312	mas_mab_cp(&tmp_mas, 0, end, mast->bn, 0);
3313	mast->bn->b_end = slot_total + 1;
3314	} else {
3315	mas_mab_cp(&tmp_mas, 0, end, mast->bn, mast->bn->b_end);
3316	}
3317
3318	/* Configure mast for splitting of mast->bn */
3319	split = mt_slots[mast->bn->type] - 2;
3320	if (left) {
3321	/* Switch mas to prev node */
3322	*mas = tmp_mas;
3323	/* Start using mast->l for the left side. */
3324	tmp_mas.node = mast->l->node;
3325	*mast->l = tmp_mas;
3326	} else {
3327	tmp_mas.node = mast->r->node;
3328	*mast->r = tmp_mas;
3329	split = slot_total - split;
3330	}
3331	split = mab_no_null_split(mast->bn, split, mt_slots[mast->bn->type]);
3332	/* Update parent slot for split calculation. */
3333	if (left)
3334	mast->orig_l->offset += end + 1;
3335
3336	mast_split_data(mast, mas, split);
3337	mast_fill_bnode(mast, mas, 2);
3338	mas_split_final_node(mast, mas, height + 1);
3339	return true;
3340	}
3341
3342	/*
3343	* mas_split() - Split data that is too big for one node into two.
3344	* @mas: The maple state
3345	* @b_node: The maple big node
3346	* Return: 1 on success, 0 on failure.
3347	*/
3348	static int mas_split(struct ma_state mas, struct maple_big_node b_node)
3349	{
3350	struct maple_subtree_state mast;
3351	int height = 0;
3352	unsigned char mid_split, split = 0;
3353	struct maple_enode *old;
3354
3355	/*
3356	* Splitting is handled differently from any other B-tree; the Maple
3357	* Tree splits upwards. Splitting up means that the split operation
3358	* occurs when the walk of the tree hits the leaves and not on the way
3359	* down. The reason for splitting up is that it is impossible to know
3360	* how much space will be needed until the leaf is (or leaves are)
3361	* reached. Since overwriting data is allowed and a range could
3362	* overwrite more than one range or result in changing one entry into 3
3363	* entries, it is impossible to know if a split is required until the
3364	* data is examined.
3365	*
3366	* Splitting is a balancing act between keeping allocations to a minimum
3367	* and avoiding a 'jitter' event where a tree is expanded to make room
3368	* for an entry followed by a contraction when the entry is removed. To
3369	* accomplish the balance, there are empty slots remaining in both left
3370	* and right nodes after a split.
3371	*/
3372	MA_STATE(l_mas, mas->tree, mas->index, mas->last);
3373	MA_STATE(r_mas, mas->tree, mas->index, mas->last);
3374	MA_STATE(prev_l_mas, mas->tree, mas->index, mas->last);
3375	MA_STATE(prev_r_mas, mas->tree, mas->index, mas->last);
3376
3377	trace_ma_op(__func__, mas);
3378	mas->depth = mas_mt_height(mas);
3379	/* Allocation failures will happen early. */
3380	mas_node_count(mas, 1 + mas->depth * 2);
3381	if (mas_is_err(mas))
3382	return 0;
3383
3384	mast.l = &l_mas;
3385	mast.r = &r_mas;
3386	mast.orig_l = &prev_l_mas;
3387	mast.orig_r = &prev_r_mas;
3388	mast.bn = b_node;
3389
3390	while (height++ <= mas->depth) {
3391	if (mt_slots[b_node->type] > b_node->b_end) {
3392	mas_split_final_node(&mast, mas, height);
3393	break;
3394	}
3395
3396	l_mas = r_mas = *mas;
3397	l_mas.node = mas_new_ma_node(mas, b_node);
3398	r_mas.node = mas_new_ma_node(mas, b_node);
3399	/*
3400	* Another way that 'jitter' is avoided is to terminate a split up early if the
3401	* left or right node has space to spare. This is referred to as "pushing left"
3402	* or "pushing right" and is similar to the B* tree, except the nodes left or
3403	* right can rarely be reused due to RCU, but the ripple upwards is halted which
3404	* is a significant savings.
3405	*/
3406	/* Try to push left. */
3407	if (mas_push_data(mas, height, &mast, true))
3408	break;
3409
3410	/* Try to push right. */
3411	if (mas_push_data(mas, height, &mast, false))
3412	break;
3413
3414	split = mab_calc_split(mas, b_node, &mid_split, prev_l_mas.min);
3415	mast_split_data(&mast, mas, split);
3416	/*
3417	* Usually correct, mab_mas_cp in the above call overwrites
3418	* r->max.
3419	*/
3420	mast.r->max = mas->max;
3421	mast_fill_bnode(&mast, mas, 1);
3422	prev_l_mas = *mast.l;
3423	prev_r_mas = *mast.r;
3424	}
3425
3426	/* Set the original node as dead */
3427	old = mas->node;
3428	mas->node = l_mas.node;
3429	mas_wmb_replace(mas, old);
3430	mtree_range_walk(mas);
3431	return 1;
3432	}
3433
3434	/*
3435	* mas_reuse_node() - Reuse the node to store the data.
3436	* @wr_mas: The maple write state
3437	* @bn: The maple big node
3438	* @end: The end of the data.
3439	*
3440	* Will always return false in RCU mode.
3441	*
3442	* Return: True if node was reused, false otherwise.
3443	*/
3444	static inline bool mas_reuse_node(struct ma_wr_state *wr_mas,
3445	struct maple_big_node *bn, unsigned char end)
3446	{
3447	/* Need to be rcu safe. */
3448	if (mt_in_rcu(wr_mas->mas->tree))
3449	return false;
3450
3451	if (end > bn->b_end) {
3452	int clear = mt_slots[wr_mas->type] - bn->b_end;
3453
3454	memset(wr_mas->slots + bn->b_end, 0, sizeof(void ) clear--);
3455	memset(wr_mas->pivots + bn->b_end, 0, sizeof(void ) clear);
3456	}
3457	mab_mas_cp(bn, 0, bn->b_end, wr_mas->mas, false);
3458	return true;
3459	}
3460
3461	/*
3462	* mas_commit_b_node() - Commit the big node into the tree.
3463	* @wr_mas: The maple write state
3464	* @b_node: The maple big node
3465	* @end: The end of the data.
3466	*/
3467	static noinline_for_kasan int mas_commit_b_node(struct ma_wr_state *wr_mas,
3468	struct maple_big_node *b_node, unsigned char end)
3469	{
3470	struct maple_node *node;
3471	struct maple_enode *old_enode;
3472	unsigned char b_end = b_node->b_end;
3473	enum maple_type b_type = b_node->type;
3474
3475	old_enode = wr_mas->mas->node;
3476	if ((b_end < mt_min_slots[b_type]) &&
3477	(!mte_is_root(old_enode)) &&
3478	(mas_mt_height(wr_mas->mas) > 1))
3479	return mas_rebalance(wr_mas->mas, b_node);
3480
3481	if (b_end >= mt_slots[b_type])
3482	return mas_split(wr_mas->mas, b_node);
3483
3484	if (mas_reuse_node(wr_mas, b_node, end))
3485	goto reuse_node;
3486
3487	mas_node_count(wr_mas->mas, 1);
3488	if (mas_is_err(wr_mas->mas))
3489	return 0;
3490
3491	node = mas_pop_node(wr_mas->mas);
3492	node->parent = mas_mn(wr_mas->mas)->parent;
3493	wr_mas->mas->node = mt_mk_node(node, b_type);
3494	mab_mas_cp(b_node, 0, b_end, wr_mas->mas, false);
3495	mas_replace_node(wr_mas->mas, old_enode);
3496	reuse_node:
3497	mas_update_gap(wr_mas->mas);
3498	return 1;
3499	}
3500
3501	/*
3502	* mas_root_expand() - Expand a root to a node
3503	* @mas: The maple state
3504	* @entry: The entry to store into the tree
3505	*/
3506	static inline int mas_root_expand(struct ma_state mas, void entry)
3507	{
3508	void *contents = mas_root_locked(mas);
3509	enum maple_type type = maple_leaf_64;
3510	struct maple_node *node;
3511	void __rcu **slots;
3512	unsigned long *pivots;
3513	int slot = 0;
3514
3515	mas_node_count(mas, 1);
3516	if (unlikely(mas_is_err(mas)))
3517	return 0;
3518
3519	node = mas_pop_node(mas);
3520	pivots = ma_pivots(node, type);
3521	slots = ma_slots(node, type);
3522	node->parent = ma_parent_ptr(mas_tree_parent(mas));
3523	mas->node = mt_mk_node(node, type);
3524
3525	if (mas->index) {
3526	if (contents) {
3527	rcu_assign_pointer(slots[slot], contents);
3528	if (likely(mas->index > 1))
3529	slot++;
3530	}
3531	pivots[slot++] = mas->index - 1;
3532	}
3533
3534	rcu_assign_pointer(slots[slot], entry);
3535	mas->offset = slot;
3536	pivots[slot] = mas->last;
3537	if (mas->last != ULONG_MAX)
3538	pivots[++slot] = ULONG_MAX;
3539
3540	mas->depth = 1;
3541	mas_set_height(mas);
3542	ma_set_meta(node, maple_leaf_64, 0, slot);
3543	/* swap the new root into the tree */
3544	rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
3545	return slot;
3546	}
3547
3548	static inline void mas_store_root(struct ma_state mas, void entry)
3549	{
3550	if (likely((mas->last != 0) \|\| (mas->index != 0)))
3551	mas_root_expand(mas, entry);
3552	else if (((unsigned long) (entry) & 3) == 2)
3553	mas_root_expand(mas, entry);
3554	else {
3555	rcu_assign_pointer(mas->tree->ma_root, entry);
3556	mas->node = MAS_START;
3557	}
3558	}
3559
3560	/*
3561	* mas_is_span_wr() - Check if the write needs to be treated as a write that
3562	* spans the node.
3563	* @mas: The maple state
3564	* @piv: The pivot value being written
3565	* @type: The maple node type
3566	* @entry: The data to write
3567	*
3568	* Spanning writes are writes that start in one node and end in another OR if
3569	* the write of a %NULL will cause the node to end with a %NULL.
3570	*
3571	* Return: True if this is a spanning write, false otherwise.
3572	*/
3573	static bool mas_is_span_wr(struct ma_wr_state *wr_mas)
3574	{
3575	unsigned long max = wr_mas->r_max;
3576	unsigned long last = wr_mas->mas->last;
3577	enum maple_type type = wr_mas->type;
3578	void *entry = wr_mas->entry;
3579
3580	/* Contained in this pivot, fast path */
3581	if (last < max)
3582	return false;
3583
3584	if (ma_is_leaf(type)) {
3585	max = wr_mas->mas->max;
3586	if (last < max)
3587	return false;
3588	}
3589
3590	if (last == max) {
3591	/*
3592	* The last entry of leaf node cannot be NULL unless it is the
3593	* rightmost node (writing ULONG_MAX), otherwise it spans slots.
3594	*/
3595	if (entry \|\| last == ULONG_MAX)
3596	return false;
3597	}
3598
3599	trace_ma_write(__func__, wr_mas->mas, wr_mas->r_max, entry);
3600	return true;
3601	}
3602
3603	static inline void mas_wr_walk_descend(struct ma_wr_state *wr_mas)
3604	{
3605	wr_mas->type = mte_node_type(wr_mas->mas->node);
3606	mas_wr_node_walk(wr_mas);
3607	wr_mas->slots = ma_slots(wr_mas->node, wr_mas->type);
3608	}
3609
3610	static inline void mas_wr_walk_traverse(struct ma_wr_state *wr_mas)
3611	{
3612	wr_mas->mas->max = wr_mas->r_max;
3613	wr_mas->mas->min = wr_mas->r_min;
3614	wr_mas->mas->node = wr_mas->content;
3615	wr_mas->mas->offset = 0;
3616	wr_mas->mas->depth++;
3617	}
3618	/*
3619	* mas_wr_walk() - Walk the tree for a write.
3620	* @wr_mas: The maple write state
3621	*
3622	* Uses mas_slot_locked() and does not need to worry about dead nodes.
3623	*
3624	* Return: True if it's contained in a node, false on spanning write.
3625	*/
3626	static bool mas_wr_walk(struct ma_wr_state *wr_mas)
3627	{
3628	struct ma_state *mas = wr_mas->mas;
3629
3630	while (true) {
3631	mas_wr_walk_descend(wr_mas);
3632	if (unlikely(mas_is_span_wr(wr_mas)))
3633	return false;
3634
3635	wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
3636	mas->offset);
3637	if (ma_is_leaf(wr_mas->type))
3638	return true;
3639
3640	mas_wr_walk_traverse(wr_mas);
3641	}
3642
3643	return true;
3644	}
3645
3646	static bool mas_wr_walk_index(struct ma_wr_state *wr_mas)
3647	{
3648	struct ma_state *mas = wr_mas->mas;
3649
3650	while (true) {
3651	mas_wr_walk_descend(wr_mas);
3652	wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
3653	mas->offset);
3654	if (ma_is_leaf(wr_mas->type))
3655	return true;
3656	mas_wr_walk_traverse(wr_mas);
3657
3658	}
3659	return true;
3660	}
3661	/*
3662	* mas_extend_spanning_null() - Extend a store of a %NULL to include surrounding %NULLs.
3663	* @l_wr_mas: The left maple write state
3664	* @r_wr_mas: The right maple write state
3665	*/
3666	static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas,
3667	struct ma_wr_state *r_wr_mas)
3668	{
3669	struct ma_state *r_mas = r_wr_mas->mas;
3670	struct ma_state *l_mas = l_wr_mas->mas;
3671	unsigned char l_slot;
3672
3673	l_slot = l_mas->offset;
3674	if (!l_wr_mas->content)
3675	l_mas->index = l_wr_mas->r_min;
3676
3677	if ((l_mas->index == l_wr_mas->r_min) &&
3678	(l_slot &&
3679	!mas_slot_locked(l_mas, l_wr_mas->slots, l_slot - 1))) {
3680	if (l_slot > 1)
3681	l_mas->index = l_wr_mas->pivots[l_slot - 2] + 1;
3682	else
3683	l_mas->index = l_mas->min;
3684
3685	l_mas->offset = l_slot - 1;
3686	}
3687
3688	if (!r_wr_mas->content) {
3689	if (r_mas->last < r_wr_mas->r_max)
3690	r_mas->last = r_wr_mas->r_max;
3691	r_mas->offset++;
3692	} else if ((r_mas->last == r_wr_mas->r_max) &&
3693	(r_mas->last < r_mas->max) &&
3694	!mas_slot_locked(r_mas, r_wr_mas->slots, r_mas->offset + 1)) {
3695	r_mas->last = mas_safe_pivot(r_mas, r_wr_mas->pivots,
3696	r_wr_mas->type, r_mas->offset + 1);
3697	r_mas->offset++;
3698	}
3699	}
3700
3701	static inline void mas_state_walk(struct ma_state mas)
3702	{
3703	void *entry;
3704
3705	entry = mas_start(mas);
3706	if (mas_is_none(mas))
3707	return NULL;
3708
3709	if (mas_is_ptr(mas))
3710	return entry;
3711
3712	return mtree_range_walk(mas);
3713	}
3714
3715	/*
3716	* mtree_lookup_walk() - Internal quick lookup that does not keep maple state up
3717	* to date.
3718	*
3719	* @mas: The maple state.
3720	*
3721	* Note: Leaves mas in undesirable state.
3722	* Return: The entry for @mas->index or %NULL on dead node.
3723	*/
3724	static inline void mtree_lookup_walk(struct ma_state mas)
3725	{
3726	unsigned long *pivots;
3727	unsigned char offset;
3728	struct maple_node *node;
3729	struct maple_enode *next;
3730	enum maple_type type;
3731	void __rcu **slots;
3732	unsigned char end;
3733	unsigned long max;
3734
3735	next = mas->node;
3736	max = ULONG_MAX;
3737	do {
3738	offset = 0;
3739	node = mte_to_node(next);
3740	type = mte_node_type(next);
3741	pivots = ma_pivots(node, type);
3742	end = ma_data_end(node, type, pivots, max);
3743	if (unlikely(ma_dead_node(node)))
3744	goto dead_node;
3745	do {
3746	if (pivots[offset] >= mas->index) {
3747	max = pivots[offset];
3748	break;
3749	}
3750	} while (++offset < end);
3751
3752	slots = ma_slots(node, type);
3753	next = mt_slot(mas->tree, slots, offset);
3754	if (unlikely(ma_dead_node(node)))
3755	goto dead_node;
3756	} while (!ma_is_leaf(type));
3757
3758	return (void *)next;
3759
3760	dead_node:
3761	mas_reset(mas);
3762	return NULL;
3763	}
3764
3765	static void mte_destroy_walk(struct maple_enode , struct maple_tree );
3766	/*
3767	* mas_new_root() - Create a new root node that only contains the entry passed
3768	* in.
3769	* @mas: The maple state
3770	* @entry: The entry to store.
3771	*
3772	* Only valid when the index == 0 and the last == ULONG_MAX
3773	*
3774	* Return 0 on error, 1 on success.
3775	*/
3776	static inline int mas_new_root(struct ma_state mas, void entry)
3777	{
3778	struct maple_enode *root = mas_root_locked(mas);
3779	enum maple_type type = maple_leaf_64;
3780	struct maple_node *node;
3781	void __rcu **slots;
3782	unsigned long *pivots;
3783
3784	if (!entry && !mas->index && mas->last == ULONG_MAX) {
3785	mas->depth = 0;
3786	mas_set_height(mas);
3787	rcu_assign_pointer(mas->tree->ma_root, entry);
3788	mas->node = MAS_START;
3789	goto done;
3790	}
3791
3792	mas_node_count(mas, 1);
3793	if (mas_is_err(mas))
3794	return 0;
3795
3796	node = mas_pop_node(mas);
3797	pivots = ma_pivots(node, type);
3798	slots = ma_slots(node, type);
3799	node->parent = ma_parent_ptr(mas_tree_parent(mas));
3800	mas->node = mt_mk_node(node, type);
3801	rcu_assign_pointer(slots[0], entry);
3802	pivots[0] = mas->last;
3803	mas->depth = 1;
3804	mas_set_height(mas);
3805	rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
3806
3807	done:
3808	if (xa_is_node(root))
3809	mte_destroy_walk(root, mas->tree);
3810
3811	return 1;
3812	}
3813	/*
3814	* mas_wr_spanning_store() - Create a subtree with the store operation completed
3815	* and new nodes where necessary, then place the sub-tree in the actual tree.
3816	* Note that mas is expected to point to the node which caused the store to
3817	* span.
3818	* @wr_mas: The maple write state
3819	*
3820	* Return: 0 on error, positive on success.
3821	*/
3822	static inline int mas_wr_spanning_store(struct ma_wr_state *wr_mas)
3823	{
3824	struct maple_subtree_state mast;
3825	struct maple_big_node b_node;
3826	struct ma_state *mas;
3827	unsigned char height;
3828
3829	/* Left and Right side of spanning store */
3830	MA_STATE(l_mas, NULL, 0, 0);
3831	MA_STATE(r_mas, NULL, 0, 0);
3832	MA_WR_STATE(r_wr_mas, &r_mas, wr_mas->entry);
3833	MA_WR_STATE(l_wr_mas, &l_mas, wr_mas->entry);
3834
3835	/*
3836	* A store operation that spans multiple nodes is called a spanning
3837	* store and is handled early in the store call stack by the function
3838	* mas_is_span_wr(). When a spanning store is identified, the maple
3839	* state is duplicated. The first maple state walks the left tree path
3840	* to ``index``, the duplicate walks the right tree path to ``last``.
3841	* The data in the two nodes are combined into a single node, two nodes,
3842	* or possibly three nodes (see the 3-way split above). A ``NULL``
3843	* written to the last entry of a node is considered a spanning store as
3844	* a rebalance is required for the operation to complete and an overflow
3845	* of data may happen.
3846	*/
3847	mas = wr_mas->mas;
3848	trace_ma_op(__func__, mas);
3849
3850	if (unlikely(!mas->index && mas->last == ULONG_MAX))
3851	return mas_new_root(mas, wr_mas->entry);
3852	/*
3853	* Node rebalancing may occur due to this store, so there may be three new
3854	* entries per level plus a new root.
3855	*/
3856	height = mas_mt_height(mas);
3857	mas_node_count(mas, 1 + height * 3);
3858	if (mas_is_err(mas))
3859	return 0;
3860
3861	/*
3862	* Set up right side. Need to get to the next offset after the spanning
3863	* store to ensure it's not NULL and to combine both the next node and
3864	* the node with the start together.
3865	*/
3866	r_mas = *mas;
3867	/* Avoid overflow, walk to next slot in the tree. */
3868	if (r_mas.last + 1)
3869	r_mas.last++;
3870
3871	r_mas.index = r_mas.last;
3872	mas_wr_walk_index(&r_wr_mas);
3873	r_mas.last = r_mas.index = mas->last;
3874
3875	/* Set up left side. */
3876	l_mas = *mas;
3877	mas_wr_walk_index(&l_wr_mas);
3878
3879	if (!wr_mas->entry) {
3880	mas_extend_spanning_null(&l_wr_mas, &r_wr_mas);
3881	mas->offset = l_mas.offset;
3882	mas->index = l_mas.index;
3883	mas->last = l_mas.last = r_mas.last;
3884	}
3885
3886	/* expanding NULLs may make this cover the entire range */
3887	if (!l_mas.index && r_mas.last == ULONG_MAX) {
3888	mas_set_range(mas, 0, ULONG_MAX);
3889	return mas_new_root(mas, wr_mas->entry);
3890	}
3891
3892	memset(&b_node, 0, sizeof(struct maple_big_node));
3893	/* Copy l_mas and store the value in b_node. */
3894	mas_store_b_node(&l_wr_mas, &b_node, l_wr_mas.node_end);
3895	/* Copy r_mas into b_node. */
3896	if (r_mas.offset <= r_wr_mas.node_end)
3897	mas_mab_cp(&r_mas, r_mas.offset, r_wr_mas.node_end,
3898	&b_node, b_node.b_end + 1);
3899	else
3900	b_node.b_end++;
3901
3902	/* Stop spanning searches by searching for just index. */
3903	l_mas.index = l_mas.last = mas->index;
3904
3905	mast.bn = &b_node;
3906	mast.orig_l = &l_mas;
3907	mast.orig_r = &r_mas;
3908	/* Combine l_mas and r_mas and split them up evenly again. */
3909	return mas_spanning_rebalance(mas, &mast, height + 1);
3910	}
3911
3912	/*
3913	* mas_wr_node_store() - Attempt to store the value in a node
3914	* @wr_mas: The maple write state
3915	*
3916	* Attempts to reuse the node, but may allocate.
3917	*
3918	* Return: True if stored, false otherwise
3919	*/
3920	static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas,
3921	unsigned char new_end)
3922	{
3923	struct ma_state *mas = wr_mas->mas;
3924	void __rcu **dst_slots;
3925	unsigned long *dst_pivots;
3926	unsigned char dst_offset, offset_end = wr_mas->offset_end;
3927	struct maple_node reuse, *newnode;
3928	unsigned char copy_size, node_pivots = mt_pivots[wr_mas->type];
3929	bool in_rcu = mt_in_rcu(mas->tree);
3930
3931	/* Check if there is enough data. The room is enough. */
3932	if (!mte_is_root(mas->node) && (new_end <= mt_min_slots[wr_mas->type]) &&
3933	!(mas->mas_flags & MA_STATE_BULK))
3934	return false;
3935
3936	if (mas->last == wr_mas->end_piv)
3937	offset_end++; /* don't copy this offset */
3938	else if (unlikely(wr_mas->r_max == ULONG_MAX))
3939	mas_bulk_rebalance(mas, wr_mas->node_end, wr_mas->type);
3940
3941	/* set up node. */
3942	if (in_rcu) {
3943	mas_node_count(mas, 1);
3944	if (mas_is_err(mas))
3945	return false;
3946
3947	newnode = mas_pop_node(mas);
3948	} else {
3949	memset(&reuse, 0, sizeof(struct maple_node));
3950	newnode = &reuse;
3951	}
3952
3953	newnode->parent = mas_mn(mas)->parent;
3954	dst_pivots = ma_pivots(newnode, wr_mas->type);
3955	dst_slots = ma_slots(newnode, wr_mas->type);
3956	/* Copy from start to insert point */
3957	memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset);
3958	memcpy(dst_slots, wr_mas->slots, sizeof(void ) mas->offset);
3959
3960	/* Handle insert of new range starting after old range */
3961	if (wr_mas->r_min < mas->index) {
3962	rcu_assign_pointer(dst_slots[mas->offset], wr_mas->content);
3963	dst_pivots[mas->offset++] = mas->index - 1;
3964	}
3965
3966	/* Store the new entry and range end. */
3967	if (mas->offset < node_pivots)
3968	dst_pivots[mas->offset] = mas->last;
3969	rcu_assign_pointer(dst_slots[mas->offset], wr_mas->entry);
3970
3971	/*
3972	* this range wrote to the end of the node or it overwrote the rest of
3973	* the data
3974	*/
3975	if (offset_end > wr_mas->node_end)
3976	goto done;
3977
3978	dst_offset = mas->offset + 1;
3979	/* Copy to the end of node if necessary. */
3980	copy_size = wr_mas->node_end - offset_end + 1;
3981	memcpy(dst_slots + dst_offset, wr_mas->slots + offset_end,
3982	sizeof(void ) copy_size);
3983	memcpy(dst_pivots + dst_offset, wr_mas->pivots + offset_end,
3984	sizeof(unsigned long) * (copy_size - 1));
3985
3986	if (new_end < node_pivots)
3987	dst_pivots[new_end] = mas->max;
3988
3989	done:
3990	mas_leaf_set_meta(mas, newnode, dst_pivots, maple_leaf_64, new_end);
3991	if (in_rcu) {
3992	struct maple_enode *old_enode = mas->node;
3993
3994	mas->node = mt_mk_node(newnode, wr_mas->type);
3995	mas_replace_node(mas, old_enode);
3996	} else {
3997	memcpy(wr_mas->node, newnode, sizeof(struct maple_node));
3998	}
3999	trace_ma_write(__func__, mas, 0, wr_mas->entry);
4000	mas_update_gap(mas);
4001	return true;
4002	}
4003
4004	/*
4005	* mas_wr_slot_store: Attempt to store a value in a slot.
4006	* @wr_mas: the maple write state
4007	*
4008	* Return: True if stored, false otherwise
4009	*/
4010	static inline bool mas_wr_slot_store(struct ma_wr_state *wr_mas)
4011	{
4012	struct ma_state *mas = wr_mas->mas;
4013	unsigned char offset = mas->offset;
4014	void __rcu **slots = wr_mas->slots;
4015	bool gap = false;
4016
4017	gap \|= !mt_slot_locked(mas->tree, slots, offset);
4018	gap \|= !mt_slot_locked(mas->tree, slots, offset + 1);
4019
4020	if (wr_mas->offset_end - offset == 1) {
4021	if (mas->index == wr_mas->r_min) {
4022	/* Overwriting the range and a part of the next one */
4023	rcu_assign_pointer(slots[offset], wr_mas->entry);
4024	wr_mas->pivots[offset] = mas->last;
4025	} else {
4026	/* Overwriting a part of the range and the next one */
4027	rcu_assign_pointer(slots[offset + 1], wr_mas->entry);
4028	wr_mas->pivots[offset] = mas->index - 1;
4029	mas->offset++; /* Keep mas accurate. */
4030	}
4031	} else if (!mt_in_rcu(mas->tree)) {
4032	/*
4033	* Expand the range, only partially overwriting the previous and
4034	* next ranges
4035	*/
4036	gap \|= !mt_slot_locked(mas->tree, slots, offset + 2);
4037	rcu_assign_pointer(slots[offset + 1], wr_mas->entry);
4038	wr_mas->pivots[offset] = mas->index - 1;
4039	wr_mas->pivots[offset + 1] = mas->last;
4040	mas->offset++; /* Keep mas accurate. */
4041	} else {
4042	return false;
4043	}
4044
4045	trace_ma_write(__func__, mas, 0, wr_mas->entry);
4046	/*
4047	* Only update gap when the new entry is empty or there is an empty
4048	* entry in the original two ranges.
4049	*/
4050	if (!wr_mas->entry \|\| gap)
4051	mas_update_gap(mas);
4052
4053	return true;
4054	}
4055
4056	static inline void mas_wr_extend_null(struct ma_wr_state *wr_mas)
4057	{
4058	struct ma_state *mas = wr_mas->mas;
4059
4060	if (!wr_mas->slots[wr_mas->offset_end]) {
4061	/* If this one is null, the next and prev are not */
4062	mas->last = wr_mas->end_piv;
4063	} else {
4064	/* Check next slot(s) if we are overwriting the end */
4065	if ((mas->last == wr_mas->end_piv) &&
4066	(wr_mas->node_end != wr_mas->offset_end) &&
4067	!wr_mas->slots[wr_mas->offset_end + 1]) {
4068	wr_mas->offset_end++;
4069	if (wr_mas->offset_end == wr_mas->node_end)
4070	mas->last = mas->max;
4071	else
4072	mas->last = wr_mas->pivots[wr_mas->offset_end];
4073	wr_mas->end_piv = mas->last;
4074	}
4075	}
4076
4077	if (!wr_mas->content) {
4078	/* If this one is null, the next and prev are not */
4079	mas->index = wr_mas->r_min;
4080	} else {
4081	/* Check prev slot if we are overwriting the start */
4082	if (mas->index == wr_mas->r_min && mas->offset &&
4083	!wr_mas->slots[mas->offset - 1]) {
4084	mas->offset--;
4085	wr_mas->r_min = mas->index =
4086	mas_safe_min(mas, wr_mas->pivots, mas->offset);
4087	wr_mas->r_max = wr_mas->pivots[mas->offset];
4088	}
4089	}
4090	}
4091
4092	static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas)
4093	{
4094	while ((wr_mas->offset_end < wr_mas->node_end) &&
4095	(wr_mas->mas->last > wr_mas->pivots[wr_mas->offset_end]))
4096	wr_mas->offset_end++;
4097
4098	if (wr_mas->offset_end < wr_mas->node_end)
4099	wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end];
4100	else
4101	wr_mas->end_piv = wr_mas->mas->max;
4102
4103	if (!wr_mas->entry)
4104	mas_wr_extend_null(wr_mas);
4105	}
4106
4107	static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
4108	{
4109	struct ma_state *mas = wr_mas->mas;
4110	unsigned char new_end = wr_mas->node_end + 2;
4111
4112	new_end -= wr_mas->offset_end - mas->offset;
4113	if (wr_mas->r_min == mas->index)
4114	new_end--;
4115
4116	if (wr_mas->end_piv == mas->last)
4117	new_end--;
4118
4119	return new_end;
4120	}
4121
4122	/*
4123	* mas_wr_append: Attempt to append
4124	* @wr_mas: the maple write state
4125	* @new_end: The end of the node after the modification
4126	*
4127	* This is currently unsafe in rcu mode since the end of the node may be cached
4128	* by readers while the node contents may be updated which could result in
4129	* inaccurate information.
4130	*
4131	* Return: True if appended, false otherwise
4132	*/
4133	static inline bool mas_wr_append(struct ma_wr_state *wr_mas,
4134	unsigned char new_end)
4135	{
4136	struct ma_state *mas;
4137	void __rcu **slots;
4138	unsigned char end;
4139
4140	mas = wr_mas->mas;
4141	if (mt_in_rcu(mas->tree))
4142	return false;
4143
4144	if (mas->offset != wr_mas->node_end)
4145	return false;
4146
4147	end = wr_mas->node_end;
4148	if (mas->offset != end)
4149	return false;
4150
4151	if (new_end < mt_pivots[wr_mas->type]) {
4152	wr_mas->pivots[new_end] = wr_mas->pivots[end];
4153	ma_set_meta(wr_mas->node, wr_mas->type, 0, new_end);
4154	}
4155
4156	slots = wr_mas->slots;
4157	if (new_end == end + 1) {
4158	if (mas->last == wr_mas->r_max) {
4159	/* Append to end of range */
4160	rcu_assign_pointer(slots[new_end], wr_mas->entry);
4161	wr_mas->pivots[end] = mas->index - 1;
4162	mas->offset = new_end;
4163	} else {
4164	/* Append to start of range */
4165	rcu_assign_pointer(slots[new_end], wr_mas->content);
4166	wr_mas->pivots[end] = mas->last;
4167	rcu_assign_pointer(slots[end], wr_mas->entry);
4168	}
4169	} else {
4170	/* Append to the range without touching any boundaries. */
4171	rcu_assign_pointer(slots[new_end], wr_mas->content);
4172	wr_mas->pivots[end + 1] = mas->last;
4173	rcu_assign_pointer(slots[end + 1], wr_mas->entry);
4174	wr_mas->pivots[end] = mas->index - 1;
4175	mas->offset = end + 1;
4176	}
4177
4178	if (!wr_mas->content \|\| !wr_mas->entry)
4179	mas_update_gap(mas);
4180
4181	trace_ma_write(__func__, mas, new_end, wr_mas->entry);
4182	return true;
4183	}
4184
4185	/*
4186	* mas_wr_bnode() - Slow path for a modification.
4187	* @wr_mas: The write maple state
4188	*
4189	* This is where split, rebalance end up.
4190	*/
4191	static void mas_wr_bnode(struct ma_wr_state *wr_mas)
4192	{
4193	struct maple_big_node b_node;
4194
4195	trace_ma_write(__func__, wr_mas->mas, 0, wr_mas->entry);
4196	memset(&b_node, 0, sizeof(struct maple_big_node));
4197	mas_store_b_node(wr_mas, &b_node, wr_mas->offset_end);
4198	mas_commit_b_node(wr_mas, &b_node, wr_mas->node_end);
4199	}
4200
4201	static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
4202	{
4203	struct ma_state *mas = wr_mas->mas;
4204	unsigned char new_end;
4205
4206	/* Direct replacement */
4207	if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) {
4208	rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);
4209	if (!!wr_mas->entry ^ !!wr_mas->content)
4210	mas_update_gap(mas);
4211	return;
4212	}
4213
4214	/*
4215	* new_end exceeds the size of the maple node and cannot enter the fast
4216	* path.
4217	*/
4218	new_end = mas_wr_new_end(wr_mas);
4219	if (new_end >= mt_slots[wr_mas->type])
4220	goto slow_path;
4221
4222	/* Attempt to append */
4223	if (mas_wr_append(wr_mas, new_end))
4224	return;
4225
4226	if (new_end == wr_mas->node_end && mas_wr_slot_store(wr_mas))
4227	return;
4228
4229	if (mas_wr_node_store(wr_mas, new_end))
4230	return;
4231
4232	if (mas_is_err(mas))
4233	return;
4234
4235	slow_path:
4236	mas_wr_bnode(wr_mas);
4237	}
4238
4239	/*
4240	* mas_wr_store_entry() - Internal call to store a value
4241	* @mas: The maple state
4242	* @entry: The entry to store.
4243	*
4244	* Return: The contents that was stored at the index.
4245	*/
4246	static inline void mas_wr_store_entry(struct ma_wr_state wr_mas)
4247	{
4248	struct ma_state *mas = wr_mas->mas;
4249
4250	wr_mas->content = mas_start(mas);
4251	if (mas_is_none(mas) \|\| mas_is_ptr(mas)) {
4252	mas_store_root(mas, wr_mas->entry);
4253	return wr_mas->content;
4254	}
4255
4256	if (unlikely(!mas_wr_walk(wr_mas))) {
4257	mas_wr_spanning_store(wr_mas);
4258	return wr_mas->content;
4259	}
4260
4261	/* At this point, we are at the leaf node that needs to be altered. */
4262	mas_wr_end_piv(wr_mas);
4263	/* New root for a single pointer */
4264	if (unlikely(!mas->index && mas->last == ULONG_MAX)) {
4265	mas_new_root(mas, wr_mas->entry);
4266	return wr_mas->content;
4267	}
4268
4269	mas_wr_modify(wr_mas);
4270	return wr_mas->content;
4271	}
4272
4273	/**
4274	* mas_insert() - Internal call to insert a value
4275	* @mas: The maple state
4276	* @entry: The entry to store
4277	*
4278	* Return: %NULL or the contents that already exists at the requested index
4279	* otherwise. The maple state needs to be checked for error conditions.
4280	*/
4281	static inline void mas_insert(struct ma_state mas, void *entry)
4282	{
4283	MA_WR_STATE(wr_mas, mas, entry);
4284
4285	/*
4286	* Inserting a new range inserts either 0, 1, or 2 pivots within the
4287	* tree. If the insert fits exactly into an existing gap with a value
4288	* of NULL, then the slot only needs to be written with the new value.
4289	* If the range being inserted is adjacent to another range, then only a
4290	* single pivot needs to be inserted (as well as writing the entry). If
4291	* the new range is within a gap but does not touch any other ranges,
4292	* then two pivots need to be inserted: the start - 1, and the end. As
4293	* usual, the entry must be written. Most operations require a new node
4294	* to be allocated and replace an existing node to ensure RCU safety,
4295	* when in RCU mode. The exception to requiring a newly allocated node
4296	* is when inserting at the end of a node (appending). When done
4297	* carefully, appending can reuse the node in place.
4298	*/
4299	wr_mas.content = mas_start(mas);
4300	if (wr_mas.content)
4301	goto exists;
4302
4303	if (mas_is_none(mas) \|\| mas_is_ptr(mas)) {
4304	mas_store_root(mas, entry);
4305	return NULL;
4306	}
4307
4308	/* spanning writes always overwrite something */
4309	if (!mas_wr_walk(&wr_mas))
4310	goto exists;
4311
4312	/* At this point, we are at the leaf node that needs to be altered. */
4313	wr_mas.offset_end = mas->offset;
4314	wr_mas.end_piv = wr_mas.r_max;
4315
4316	if (wr_mas.content \|\| (mas->last > wr_mas.r_max))
4317	goto exists;
4318
4319	if (!entry)
4320	return NULL;
4321
4322	mas_wr_modify(&wr_mas);
4323	return wr_mas.content;
4324
4325	exists:
4326	mas_set_err(mas, -EEXIST);
4327	return wr_mas.content;
4328
4329	}
4330
4331	static inline void mas_rewalk(struct ma_state *mas, unsigned long index)
4332	{
4333	retry:
4334	mas_set(mas, index);
4335	mas_state_walk(mas);
4336	if (mas_is_start(mas))
4337	goto retry;
4338	}
4339
4340	static inline bool mas_rewalk_if_dead(struct ma_state *mas,
4341	struct maple_node *node, const unsigned long index)
4342	{
4343	if (unlikely(ma_dead_node(node))) {
4344	mas_rewalk(mas, index);
4345	return true;
4346	}
4347	return false;
4348	}
4349
4350	/*
4351	* mas_prev_node() - Find the prev non-null entry at the same level in the
4352	* tree. The prev value will be mas->node[mas->offset] or MAS_NONE.
4353	* @mas: The maple state
4354	* @min: The lower limit to search
4355	*
4356	* The prev node value will be mas->node[mas->offset] or MAS_NONE.
4357	* Return: 1 if the node is dead, 0 otherwise.
4358	*/
4359	static inline int mas_prev_node(struct ma_state *mas, unsigned long min)
4360	{
4361	enum maple_type mt;
4362	int offset, level;
4363	void __rcu **slots;
4364	struct maple_node *node;
4365	unsigned long *pivots;
4366	unsigned long max;
4367
4368	node = mas_mn(mas);
4369	if (!mas->min)
4370	goto no_entry;
4371
4372	max = mas->min - 1;
4373	if (max < min)
4374	goto no_entry;
4375
4376	level = 0;
4377	do {
4378	if (ma_is_root(node))
4379	goto no_entry;
4380
4381	/* Walk up. */
4382	if (unlikely(mas_ascend(mas)))
4383	return 1;
4384	offset = mas->offset;
4385	level++;
4386	node = mas_mn(mas);
4387	} while (!offset);
4388
4389	offset--;
4390	mt = mte_node_type(mas->node);
4391	while (level > 1) {
4392	level--;
4393	slots = ma_slots(node, mt);
4394	mas->node = mas_slot(mas, slots, offset);
4395	if (unlikely(ma_dead_node(node)))
4396	return 1;
4397
4398	mt = mte_node_type(mas->node);
4399	node = mas_mn(mas);
4400	pivots = ma_pivots(node, mt);
4401	offset = ma_data_end(node, mt, pivots, max);
4402	if (unlikely(ma_dead_node(node)))
4403	return 1;
4404	}
4405
4406	slots = ma_slots(node, mt);
4407	mas->node = mas_slot(mas, slots, offset);
4408	pivots = ma_pivots(node, mt);
4409	if (unlikely(ma_dead_node(node)))
4410	return 1;
4411
4412	if (likely(offset))
4413	mas->min = pivots[offset - 1] + 1;
4414	mas->max = max;
4415	mas->offset = mas_data_end(mas);
4416	if (unlikely(mte_dead_node(mas->node)))
4417	return 1;
4418
4419	return 0;
4420
4421	no_entry:
4422	if (unlikely(ma_dead_node(node)))
4423	return 1;
4424
4425	mas->node = MAS_NONE;
4426	return 0;
4427	}
4428
4429	/*
4430	* mas_prev_slot() - Get the entry in the previous slot
4431	*
4432	* @mas: The maple state
4433	* @max: The minimum starting range
4434	* @empty: Can be empty
4435	* @set_underflow: Set the @mas->node to underflow state on limit.
4436	*
4437	* Return: The entry in the previous slot which is possibly NULL
4438	*/
4439	static void mas_prev_slot(struct ma_state mas, unsigned long min, bool empty,
4440	bool set_underflow)
4441	{
4442	void *entry;
4443	void __rcu **slots;
4444	unsigned long pivot;
4445	enum maple_type type;
4446	unsigned long *pivots;
4447	struct maple_node *node;
4448	unsigned long save_point = mas->index;
4449
4450	retry:
4451	node = mas_mn(mas);
4452	type = mte_node_type(mas->node);
4453	pivots = ma_pivots(node, type);
4454	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4455	goto retry;
4456
4457	if (mas->min <= min) {
4458	pivot = mas_safe_min(mas, pivots, mas->offset);
4459
4460	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4461	goto retry;
4462
4463	if (pivot <= min)
4464	goto underflow;
4465	}
4466
4467	again:
4468	if (likely(mas->offset)) {
4469	mas->offset--;
4470	mas->last = mas->index - 1;
4471	mas->index = mas_safe_min(mas, pivots, mas->offset);
4472	} else {
4473	if (mas_prev_node(mas, min)) {
4474	mas_rewalk(mas, save_point);
4475	goto retry;
4476	}
4477
4478	if (mas_is_none(mas))
4479	goto underflow;
4480
4481	mas->last = mas->max;
4482	node = mas_mn(mas);
4483	type = mte_node_type(mas->node);
4484	pivots = ma_pivots(node, type);
4485	mas->index = pivots[mas->offset - 1] + 1;
4486	}
4487
4488	slots = ma_slots(node, type);
4489	entry = mas_slot(mas, slots, mas->offset);
4490	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4491	goto retry;
4492
4493	if (likely(entry))
4494	return entry;
4495
4496	if (!empty) {
4497	if (mas->index <= min)
4498	goto underflow;
4499
4500	goto again;
4501	}
4502
4503	return entry;
4504
4505	underflow:
4506	if (set_underflow)
4507	mas->node = MAS_UNDERFLOW;
4508	return NULL;
4509	}
4510
4511	/*
4512	* mas_next_node() - Get the next node at the same level in the tree.
4513	* @mas: The maple state
4514	* @max: The maximum pivot value to check.
4515	*
4516	* The next value will be mas->node[mas->offset] or MAS_NONE.
4517	* Return: 1 on dead node, 0 otherwise.
4518	*/
4519	static inline int mas_next_node(struct ma_state mas, struct maple_node node,
4520	unsigned long max)
4521	{
4522	unsigned long min;
4523	unsigned long *pivots;
4524	struct maple_enode *enode;
4525	int level = 0;
4526	unsigned char node_end;
4527	enum maple_type mt;
4528	void __rcu **slots;
4529
4530	if (mas->max >= max)
4531	goto no_entry;
4532
4533	min = mas->max + 1;
4534	level = 0;
4535	do {
4536	if (ma_is_root(node))
4537	goto no_entry;
4538
4539	/* Walk up. */
4540	if (unlikely(mas_ascend(mas)))
4541	return 1;
4542
4543	level++;
4544	node = mas_mn(mas);
4545	mt = mte_node_type(mas->node);
4546	pivots = ma_pivots(node, mt);
4547	node_end = ma_data_end(node, mt, pivots, mas->max);
4548	if (unlikely(ma_dead_node(node)))
4549	return 1;
4550
4551	} while (unlikely(mas->offset == node_end));
4552
4553	slots = ma_slots(node, mt);
4554	mas->offset++;
4555	enode = mas_slot(mas, slots, mas->offset);
4556	if (unlikely(ma_dead_node(node)))
4557	return 1;
4558
4559	if (level > 1)
4560	mas->offset = 0;
4561
4562	while (unlikely(level > 1)) {
4563	level--;
4564	mas->node = enode;
4565	node = mas_mn(mas);
4566	mt = mte_node_type(mas->node);
4567	slots = ma_slots(node, mt);
4568	enode = mas_slot(mas, slots, 0);
4569	if (unlikely(ma_dead_node(node)))
4570	return 1;
4571	}
4572
4573	if (!mas->offset)
4574	pivots = ma_pivots(node, mt);
4575
4576	mas->max = mas_safe_pivot(mas, pivots, mas->offset, mt);
4577	if (unlikely(ma_dead_node(node)))
4578	return 1;
4579
4580	mas->node = enode;
4581	mas->min = min;
4582	return 0;
4583
4584	no_entry:
4585	if (unlikely(ma_dead_node(node)))
4586	return 1;
4587
4588	mas->node = MAS_NONE;
4589	return 0;
4590	}
4591
4592	/*
4593	* mas_next_slot() - Get the entry in the next slot
4594	*
4595	* @mas: The maple state
4596	* @max: The maximum starting range
4597	* @empty: Can be empty
4598	* @set_overflow: Should @mas->node be set to overflow when the limit is
4599	* reached.
4600	*
4601	* Return: The entry in the next slot which is possibly NULL
4602	*/
4603	static void mas_next_slot(struct ma_state mas, unsigned long max, bool empty,
4604	bool set_overflow)
4605	{
4606	void __rcu **slots;
4607	unsigned long *pivots;
4608	unsigned long pivot;
4609	enum maple_type type;
4610	struct maple_node *node;
4611	unsigned char data_end;
4612	unsigned long save_point = mas->last;
4613	void *entry;
4614
4615	retry:
4616	node = mas_mn(mas);
4617	type = mte_node_type(mas->node);
4618	pivots = ma_pivots(node, type);
4619	data_end = ma_data_end(node, type, pivots, mas->max);
4620	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4621	goto retry;
4622
4623	if (mas->max >= max) {
4624	if (likely(mas->offset < data_end))
4625	pivot = pivots[mas->offset];
4626	else
4627	goto overflow;
4628
4629	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4630	goto retry;
4631
4632	if (pivot >= max)
4633	goto overflow;
4634	}
4635
4636	if (likely(mas->offset < data_end)) {
4637	mas->index = pivots[mas->offset] + 1;
4638	again:
4639	mas->offset++;
4640	if (likely(mas->offset < data_end))
4641	mas->last = pivots[mas->offset];
4642	else
4643	mas->last = mas->max;
4644	} else {
4645	if (mas_next_node(mas, node, max)) {
4646	mas_rewalk(mas, save_point);
4647	goto retry;
4648	}
4649
4650	if (WARN_ON_ONCE(mas_is_none(mas))) {
4651	mas->node = MAS_OVERFLOW;
4652	return NULL;
4653	goto overflow;
4654	}
4655
4656	mas->offset = 0;
4657	mas->index = mas->min;
4658	node = mas_mn(mas);
4659	type = mte_node_type(mas->node);
4660	pivots = ma_pivots(node, type);
4661	mas->last = pivots[0];
4662	}
4663
4664	slots = ma_slots(node, type);
4665	entry = mt_slot(mas->tree, slots, mas->offset);
4666	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
4667	goto retry;
4668
4669	if (entry)
4670	return entry;
4671
4672	if (!empty) {
4673	if (mas->last >= max)
4674	goto overflow;
4675
4676	mas->index = mas->last + 1;
4677	/* Node cannot end on NULL, so it's safe to short-cut here */
4678	goto again;
4679	}
4680
4681	return entry;
4682
4683	overflow:
4684	if (set_overflow)
4685	mas->node = MAS_OVERFLOW;
4686	return NULL;
4687	}
4688
4689	/*
4690	* mas_next_entry() - Internal function to get the next entry.
4691	* @mas: The maple state
4692	* @limit: The maximum range start.
4693	*
4694	* Set the @mas->node to the next entry and the range_start to
4695	* the beginning value for the entry. Does not check beyond @limit.
4696	* Sets @mas->index and @mas->last to the range, Does not update @mas->index and
4697	* @mas->last on overflow.
4698	* Restarts on dead nodes.
4699	*
4700	* Return: the next entry or %NULL.
4701	*/
4702	static inline void mas_next_entry(struct ma_state mas, unsigned long limit)
4703	{
4704	if (mas->last >= limit) {
4705	mas->node = MAS_OVERFLOW;
4706	return NULL;
4707	}
4708
4709	return mas_next_slot(mas, limit, false, true);
4710	}
4711
4712	/*
4713	* mas_rev_awalk() - Internal function. Reverse allocation walk. Find the
4714	* highest gap address of a given size in a given node and descend.
4715	* @mas: The maple state
4716	* @size: The needed size.
4717	*
4718	* Return: True if found in a leaf, false otherwise.
4719	*
4720	*/
4721	static bool mas_rev_awalk(struct ma_state *mas, unsigned long size,
4722	unsigned long gap_min, unsigned long gap_max)
4723	{
4724	enum maple_type type = mte_node_type(mas->node);
4725	struct maple_node *node = mas_mn(mas);
4726	unsigned long pivots, gaps;
4727	void __rcu **slots;
4728	unsigned long gap = 0;
4729	unsigned long max, min;
4730	unsigned char offset;
4731
4732	if (unlikely(mas_is_err(mas)))
4733	return true;
4734
4735	if (ma_is_dense(type)) {
4736	/* dense nodes. */
4737	mas->offset = (unsigned char)(mas->index - mas->min);
4738	return true;
4739	}
4740
4741	pivots = ma_pivots(node, type);
4742	slots = ma_slots(node, type);
4743	gaps = ma_gaps(node, type);
4744	offset = mas->offset;
4745	min = mas_safe_min(mas, pivots, offset);
4746	/* Skip out of bounds. */
4747	while (mas->last < min)
4748	min = mas_safe_min(mas, pivots, --offset);
4749
4750	max = mas_safe_pivot(mas, pivots, offset, type);
4751	while (mas->index <= max) {
4752	gap = 0;
4753	if (gaps)
4754	gap = gaps[offset];
4755	else if (!mas_slot(mas, slots, offset))
4756	gap = max - min + 1;
4757
4758	if (gap) {
4759	if ((size <= gap) && (size <= mas->last - min + 1))
4760	break;
4761
4762	if (!gaps) {
4763	/* Skip the next slot, it cannot be a gap. */
4764	if (offset < 2)
4765	goto ascend;
4766
4767	offset -= 2;
4768	max = pivots[offset];
4769	min = mas_safe_min(mas, pivots, offset);
4770	continue;
4771	}
4772	}
4773
4774	if (!offset)
4775	goto ascend;
4776
4777	offset--;
4778	max = min - 1;
4779	min = mas_safe_min(mas, pivots, offset);
4780	}
4781
4782	if (unlikely((mas->index > max) \|\| (size - 1 > max - mas->index)))
4783	goto no_space;
4784
4785	if (unlikely(ma_is_leaf(type))) {
4786	mas->offset = offset;
4787	*gap_min = min;
4788	*gap_max = min + gap - 1;
4789	return true;
4790	}
4791
4792	/* descend, only happens under lock. */
4793	mas->node = mas_slot(mas, slots, offset);
4794	mas->min = min;
4795	mas->max = max;
4796	mas->offset = mas_data_end(mas);
4797	return false;
4798
4799	ascend:
4800	if (!mte_is_root(mas->node))
4801	return false;
4802
4803	no_space:
4804	mas_set_err(mas, -EBUSY);
4805	return false;
4806	}
4807
4808	static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size)
4809	{
4810	enum maple_type type = mte_node_type(mas->node);
4811	unsigned long pivot, min, gap = 0;
4812	unsigned char offset, data_end;
4813	unsigned long gaps, pivots;
4814	void __rcu **slots;
4815	struct maple_node *node;
4816	bool found = false;
4817
4818	if (ma_is_dense(type)) {
4819	mas->offset = (unsigned char)(mas->index - mas->min);
4820	return true;
4821	}
4822
4823	node = mas_mn(mas);
4824	pivots = ma_pivots(node, type);
4825	slots = ma_slots(node, type);
4826	gaps = ma_gaps(node, type);
4827	offset = mas->offset;
4828	min = mas_safe_min(mas, pivots, offset);
4829	data_end = ma_data_end(node, type, pivots, mas->max);
4830	for (; offset <= data_end; offset++) {
4831	pivot = mas_safe_pivot(mas, pivots, offset, type);
4832
4833	/* Not within lower bounds */
4834	if (mas->index > pivot)
4835	goto next_slot;
4836
4837	if (gaps)
4838	gap = gaps[offset];
4839	else if (!mas_slot(mas, slots, offset))
4840	gap = min(pivot, mas->last) - max(mas->index, min) + 1;
4841	else
4842	goto next_slot;
4843
4844	if (gap >= size) {
4845	if (ma_is_leaf(type)) {
4846	found = true;
4847	goto done;
4848	}
4849	if (mas->index <= pivot) {
4850	mas->node = mas_slot(mas, slots, offset);
4851	mas->min = min;
4852	mas->max = pivot;
4853	offset = 0;
4854	break;
4855	}
4856	}
4857	next_slot:
4858	min = pivot + 1;
4859	if (mas->last <= pivot) {
4860	mas_set_err(mas, -EBUSY);
4861	return true;
4862	}
4863	}
4864
4865	if (mte_is_root(mas->node))
4866	found = true;
4867	done:
4868	mas->offset = offset;
4869	return found;
4870	}
4871
4872	/**
4873	* mas_walk() - Search for @mas->index in the tree.
4874	* @mas: The maple state.
4875	*
4876	* mas->index and mas->last will be set to the range if there is a value. If
4877	* mas->node is MAS_NONE, reset to MAS_START.
4878	*
4879	* Return: the entry at the location or %NULL.
4880	*/
4881	void mas_walk(struct ma_state mas)
4882	{
4883	void *entry;
4884
4885	if (!mas_is_active(mas) \|\| !mas_is_start(mas))
4886	mas->node = MAS_START;
4887	retry:
4888	entry = mas_state_walk(mas);
4889	if (mas_is_start(mas)) {
4890	goto retry;
4891	} else if (mas_is_none(mas)) {
4892	mas->index = 0;
4893	mas->last = ULONG_MAX;
4894	} else if (mas_is_ptr(mas)) {
4895	if (!mas->index) {
4896	mas->last = 0;
4897	return entry;
4898	}
4899
4900	mas->index = 1;
4901	mas->last = ULONG_MAX;
4902	mas->node = MAS_NONE;
4903	return NULL;
4904	}
4905
4906	return entry;
4907	}
4908	EXPORT_SYMBOL_GPL(mas_walk);
4909
4910	static inline bool mas_rewind_node(struct ma_state *mas)
4911	{
4912	unsigned char slot;
4913
4914	do {
4915	if (mte_is_root(mas->node)) {
4916	slot = mas->offset;
4917	if (!slot)
4918	return false;
4919	} else {
4920	mas_ascend(mas);
4921	slot = mas->offset;
4922	}
4923	} while (!slot);
4924
4925	mas->offset = --slot;
4926	return true;
4927	}
4928
4929	/*
4930	* mas_skip_node() - Internal function. Skip over a node.
4931	* @mas: The maple state.
4932	*
4933	* Return: true if there is another node, false otherwise.
4934	*/
4935	static inline bool mas_skip_node(struct ma_state *mas)
4936	{
4937	if (mas_is_err(mas))
4938	return false;
4939
4940	do {
4941	if (mte_is_root(mas->node)) {
4942	if (mas->offset >= mas_data_end(mas)) {
4943	mas_set_err(mas, -EBUSY);
4944	return false;
4945	}
4946	} else {
4947	mas_ascend(mas);
4948	}
4949	} while (mas->offset >= mas_data_end(mas));
4950
4951	mas->offset++;
4952	return true;
4953	}
4954
4955	/*
4956	* mas_awalk() - Allocation walk. Search from low address to high, for a gap of
4957	* @size
4958	* @mas: The maple state
4959	* @size: The size of the gap required
4960	*
4961	* Search between @mas->index and @mas->last for a gap of @size.
4962	*/
4963	static inline void mas_awalk(struct ma_state *mas, unsigned long size)
4964	{
4965	struct maple_enode *last = NULL;
4966
4967	/*
4968	* There are 4 options:
4969	* go to child (descend)
4970	* go back to parent (ascend)
4971	* no gap found. (return, slot == MAPLE_NODE_SLOTS)
4972	* found the gap. (return, slot != MAPLE_NODE_SLOTS)
4973	*/
4974	while (!mas_is_err(mas) && !mas_anode_descend(mas, size)) {
4975	if (last == mas->node)
4976	mas_skip_node(mas);
4977	else
4978	last = mas->node;
4979	}
4980	}
4981
4982	/*
4983	* mas_sparse_area() - Internal function. Return upper or lower limit when
4984	* searching for a gap in an empty tree.
4985	* @mas: The maple state
4986	* @min: the minimum range
4987	* @max: The maximum range
4988	* @size: The size of the gap
4989	* @fwd: Searching forward or back
4990	*/
4991	static inline int mas_sparse_area(struct ma_state *mas, unsigned long min,
4992	unsigned long max, unsigned long size, bool fwd)
4993	{
4994	if (!unlikely(mas_is_none(mas)) && min == 0) {
4995	min++;
4996	/*
4997	* At this time, min is increased, we need to recheck whether
4998	* the size is satisfied.
4999	*/
5000	if (min > max \|\| max - min + 1 < size)
5001	return -EBUSY;
5002	}
5003	/* mas_is_ptr */
5004
5005	if (fwd) {
5006	mas->index = min;
5007	mas->last = min + size - 1;
5008	} else {
5009	mas->last = max;
5010	mas->index = max - size + 1;
5011	}
5012	return 0;
5013	}
5014
5015	/*
5016	* mas_empty_area() - Get the lowest address within the range that is
5017	* sufficient for the size requested.
5018	* @mas: The maple state
5019	* @min: The lowest value of the range
5020	* @max: The highest value of the range
5021	* @size: The size needed
5022	*/
5023	int mas_empty_area(struct ma_state *mas, unsigned long min,
5024	unsigned long max, unsigned long size)
5025	{
5026	unsigned char offset;
5027	unsigned long *pivots;
5028	enum maple_type mt;
5029
5030	if (min > max)
5031	return -EINVAL;
5032
5033	if (size == 0 \|\| max - min < size - 1)
5034	return -EINVAL;
5035
5036	if (mas_is_start(mas))
5037	mas_start(mas);
5038	else if (mas->offset >= 2)
5039	mas->offset -= 2;
5040	else if (!mas_skip_node(mas))
5041	return -EBUSY;
5042
5043	/* Empty set */
5044	if (mas_is_none(mas) \|\| mas_is_ptr(mas))
5045	return mas_sparse_area(mas, min, max, size, true);
5046
5047	/* The start of the window can only be within these values */
5048	mas->index = min;
5049	mas->last = max;
5050	mas_awalk(mas, size);
5051
5052	if (unlikely(mas_is_err(mas)))
5053	return xa_err(mas->node);
5054
5055	offset = mas->offset;
5056	if (unlikely(offset == MAPLE_NODE_SLOTS))
5057	return -EBUSY;
5058
5059	mt = mte_node_type(mas->node);
5060	pivots = ma_pivots(mas_mn(mas), mt);
5061	min = mas_safe_min(mas, pivots, offset);
5062	if (mas->index < min)
5063	mas->index = min;
5064	mas->last = mas->index + size - 1;
5065	return 0;
5066	}
5067	EXPORT_SYMBOL_GPL(mas_empty_area);
5068
5069	/*
5070	* mas_empty_area_rev() - Get the highest address within the range that is
5071	* sufficient for the size requested.
5072	* @mas: The maple state
5073	* @min: The lowest value of the range
5074	* @max: The highest value of the range
5075	* @size: The size needed
5076	*/
5077	int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
5078	unsigned long max, unsigned long size)
5079	{
5080	struct maple_enode *last = mas->node;
5081
5082	if (min > max)
5083	return -EINVAL;
5084
5085	if (size == 0 \|\| max - min < size - 1)
5086	return -EINVAL;
5087
5088	if (mas_is_start(mas)) {
5089	mas_start(mas);
5090	mas->offset = mas_data_end(mas);
5091	} else if (mas->offset >= 2) {
5092	mas->offset -= 2;
5093	} else if (!mas_rewind_node(mas)) {
5094	return -EBUSY;
5095	}
5096
5097	/* Empty set. */
5098	if (mas_is_none(mas) \|\| mas_is_ptr(mas))
5099	return mas_sparse_area(mas, min, max, size, false);
5100
5101	/* The start of the window can only be within these values. */
5102	mas->index = min;
5103	mas->last = max;
5104
5105	while (!mas_rev_awalk(mas, size, &min, &max)) {
5106	if (last == mas->node) {
5107	if (!mas_rewind_node(mas))
5108	return -EBUSY;
5109	} else {
5110	last = mas->node;
5111	}
5112	}
5113
5114	if (mas_is_err(mas))
5115	return xa_err(mas->node);
5116
5117	if (unlikely(mas->offset == MAPLE_NODE_SLOTS))
5118	return -EBUSY;
5119
5120	/* Trim the upper limit to the max. */
5121	if (max < mas->last)
5122	mas->last = max;
5123
5124	mas->index = mas->last - size + 1;
5125	return 0;
5126	}
5127	EXPORT_SYMBOL_GPL(mas_empty_area_rev);
5128
5129	/*
5130	* mte_dead_leaves() - Mark all leaves of a node as dead.
5131	* @mas: The maple state
5132	* @slots: Pointer to the slot array
5133	* @type: The maple node type
5134	*
5135	* Must hold the write lock.
5136	*
5137	* Return: The number of leaves marked as dead.
5138	*/
5139	static inline
5140	unsigned char mte_dead_leaves(struct maple_enode enode, struct maple_tree mt,
5141	void __rcu **slots)
5142	{
5143	struct maple_node *node;
5144	enum maple_type type;
5145	void *entry;
5146	int offset;
5147
5148	for (offset = 0; offset < mt_slot_count(enode); offset++) {
5149	entry = mt_slot(mt, slots, offset);
5150	type = mte_node_type(entry);
5151	node = mte_to_node(entry);
5152	/* Use both node and type to catch LE & BE metadata */
5153	if (!node \|\| !type)
5154	break;
5155
5156	mte_set_node_dead(entry);
5157	node->type = type;
5158	rcu_assign_pointer(slots[offset], node);
5159	}
5160
5161	return offset;
5162	}
5163
5164	/**
5165	* mte_dead_walk() - Walk down a dead tree to just before the leaves
5166	* @enode: The maple encoded node
5167	* @offset: The starting offset
5168	*
5169	* Note: This can only be used from the RCU callback context.
5170	*/
5171	static void __rcu mte_dead_walk(struct maple_enode enode, unsigned char offset)
5172	{
5173	struct maple_node node, next;
5174	void __rcu **slots = NULL;
5175
5176	next = mte_to_node(*enode);
5177	do {
5178	*enode = ma_enode_ptr(next);
5179	node = mte_to_node(*enode);
5180	slots = ma_slots(node, node->type);
5181	next = rcu_dereference_protected(slots[offset],
5182	lock_is_held(&rcu_callback_map));
5183	offset = 0;
5184	} while (!ma_is_leaf(next->type));
5185
5186	return slots;
5187	}
5188
5189	/**
5190	* mt_free_walk() - Walk & free a tree in the RCU callback context
5191	* @head: The RCU head that's within the node.
5192	*
5193	* Note: This can only be used from the RCU callback context.
5194	*/
5195	static void mt_free_walk(struct rcu_head *head)
5196	{
5197	void __rcu **slots;
5198	struct maple_node node, start;
5199	struct maple_enode *enode;
5200	unsigned char offset;
5201	enum maple_type type;
5202
5203	node = container_of(head, struct maple_node, rcu);
5204
5205	if (ma_is_leaf(node->type))
5206	goto free_leaf;
5207
5208	start = node;
5209	enode = mt_mk_node(node, node->type);
5210	slots = mte_dead_walk(&enode, 0);
5211	node = mte_to_node(enode);
5212	do {
5213	mt_free_bulk(node->slot_len, slots);
5214	offset = node->parent_slot + 1;
5215	enode = node->piv_parent;
5216	if (mte_to_node(enode) == node)
5217	goto free_leaf;
5218
5219	type = mte_node_type(enode);
5220	slots = ma_slots(mte_to_node(enode), type);
5221	if ((offset < mt_slots[type]) &&
5222	rcu_dereference_protected(slots[offset],
5223	lock_is_held(&rcu_callback_map)))
5224	slots = mte_dead_walk(&enode, offset);
5225	node = mte_to_node(enode);
5226	} while ((node != start) \|\| (node->slot_len < offset));
5227
5228	slots = ma_slots(node, node->type);
5229	mt_free_bulk(node->slot_len, slots);
5230
5231	free_leaf:
5232	mt_free_rcu(&node->rcu);
5233	}
5234
5235	static inline void __rcu mte_destroy_descend(struct maple_enode enode,
5236	struct maple_tree mt, struct maple_enode prev, unsigned char offset)
5237	{
5238	struct maple_node *node;
5239	struct maple_enode next = enode;
5240	void __rcu **slots = NULL;
5241	enum maple_type type;
5242	unsigned char next_offset = 0;
5243
5244	do {
5245	*enode = next;
5246	node = mte_to_node(*enode);
5247	type = mte_node_type(*enode);
5248	slots = ma_slots(node, type);
5249	next = mt_slot_locked(mt, slots, next_offset);
5250	if ((mte_dead_node(next)))
5251	next = mt_slot_locked(mt, slots, ++next_offset);
5252
5253	mte_set_node_dead(*enode);
5254	node->type = type;
5255	node->piv_parent = prev;
5256	node->parent_slot = offset;
5257	offset = next_offset;
5258	next_offset = 0;
5259	prev = *enode;
5260	} while (!mte_is_leaf(next));
5261
5262	return slots;
5263	}
5264
5265	static void mt_destroy_walk(struct maple_enode enode, struct maple_tree mt,
5266	bool free)
5267	{
5268	void __rcu **slots;
5269	struct maple_node *node = mte_to_node(enode);
5270	struct maple_enode *start;
5271
5272	if (mte_is_leaf(enode)) {
5273	node->type = mte_node_type(enode);
5274	goto free_leaf;
5275	}
5276
5277	start = enode;
5278	slots = mte_destroy_descend(&enode, mt, start, 0);
5279	node = mte_to_node(enode); // Updated in the above call.
5280	do {
5281	enum maple_type type;
5282	unsigned char offset;
5283	struct maple_enode parent, tmp;
5284
5285	node->slot_len = mte_dead_leaves(enode, mt, slots);
5286	if (free)
5287	mt_free_bulk(node->slot_len, slots);
5288	offset = node->parent_slot + 1;
5289	enode = node->piv_parent;
5290	if (mte_to_node(enode) == node)
5291	goto free_leaf;
5292
5293	type = mte_node_type(enode);
5294	slots = ma_slots(mte_to_node(enode), type);
5295	if (offset >= mt_slots[type])
5296	goto next;
5297
5298	tmp = mt_slot_locked(mt, slots, offset);
5299	if (mte_node_type(tmp) && mte_to_node(tmp)) {
5300	parent = enode;
5301	enode = tmp;
5302	slots = mte_destroy_descend(&enode, mt, parent, offset);
5303	}
5304	next:
5305	node = mte_to_node(enode);
5306	} while (start != enode);
5307
5308	node = mte_to_node(enode);
5309	node->slot_len = mte_dead_leaves(enode, mt, slots);
5310	if (free)
5311	mt_free_bulk(node->slot_len, slots);
5312
5313	free_leaf:
5314	if (free)
5315	mt_free_rcu(&node->rcu);
5316	else
5317	mt_clear_meta(mt, node, node->type);
5318	}
5319
5320	/*
5321	* mte_destroy_walk() - Free a tree or sub-tree.
5322	* @enode: the encoded maple node (maple_enode) to start
5323	* @mt: the tree to free - needed for node types.
5324	*
5325	* Must hold the write lock.
5326	*/
5327	static inline void mte_destroy_walk(struct maple_enode *enode,
5328	struct maple_tree *mt)
5329	{
5330	struct maple_node *node = mte_to_node(enode);
5331
5332	if (mt_in_rcu(mt)) {
5333	mt_destroy_walk(enode, mt, false);
5334	call_rcu(&node->rcu, mt_free_walk);
5335	} else {
5336	mt_destroy_walk(enode, mt, true);
5337	}
5338	}
5339
5340	static void mas_wr_store_setup(struct ma_wr_state *wr_mas)
5341	{
5342	if (!mas_is_active(wr_mas->mas)) {
5343	if (mas_is_start(wr_mas->mas))
5344	return;
5345
5346	if (unlikely(mas_is_paused(wr_mas->mas)))
5347	goto reset;
5348
5349	if (unlikely(mas_is_none(wr_mas->mas)))
5350	goto reset;
5351
5352	if (unlikely(mas_is_overflow(wr_mas->mas)))
5353	goto reset;
5354
5355	if (unlikely(mas_is_underflow(wr_mas->mas)))
5356	goto reset;
5357	}
5358
5359	/*
5360	* A less strict version of mas_is_span_wr() where we allow spanning
5361	* writes within this node. This is to stop partial walks in
5362	* mas_prealloc() from being reset.
5363	*/
5364	if (wr_mas->mas->last > wr_mas->mas->max)
5365	goto reset;
5366
5367	if (wr_mas->entry)
5368	return;
5369
5370	if (mte_is_leaf(wr_mas->mas->node) &&
5371	wr_mas->mas->last == wr_mas->mas->max)
5372	goto reset;
5373
5374	return;
5375
5376	reset:
5377	mas_reset(wr_mas->mas);
5378	}
5379
5380	/* Interface */
5381
5382	/**
5383	* mas_store() - Store an @entry.
5384	* @mas: The maple state.
5385	* @entry: The entry to store.
5386	*
5387	* The @mas->index and @mas->last is used to set the range for the @entry.
5388	* Note: The @mas should have pre-allocated entries to ensure there is memory to
5389	* store the entry. Please see mas_expected_entries()/mas_destroy() for more details.
5390	*
5391	* Return: the first entry between mas->index and mas->last or %NULL.
5392	*/
5393	void mas_store(struct ma_state mas, void *entry)
5394	{
5395	MA_WR_STATE(wr_mas, mas, entry);
5396
5397	trace_ma_write(__func__, mas, 0, entry);
5398	#ifdef CONFIG_DEBUG_MAPLE_TREE
5399	if (MAS_WARN_ON(mas, mas->index > mas->last))
5400	pr_err("Error %lX > %lX %p\n", mas->index, mas->last, entry);
5401
5402	if (mas->index > mas->last) {
5403	mas_set_err(mas, -EINVAL);
5404	return NULL;
5405	}
5406
5407	#endif
5408
5409	/*
5410	* Storing is the same operation as insert with the added caveat that it
5411	* can overwrite entries. Although this seems simple enough, one may
5412	* want to examine what happens if a single store operation was to
5413	* overwrite multiple entries within a self-balancing B-Tree.
5414	*/
5415	mas_wr_store_setup(&wr_mas);
5416	mas_wr_store_entry(&wr_mas);
5417	return wr_mas.content;
5418	}
5419	EXPORT_SYMBOL_GPL(mas_store);
5420
5421	/**
5422	* mas_store_gfp() - Store a value into the tree.
5423	* @mas: The maple state
5424	* @entry: The entry to store
5425	* @gfp: The GFP_FLAGS to use for allocations if necessary.
5426	*
5427	* Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
5428	* be allocated.
5429	*/
5430	int mas_store_gfp(struct ma_state mas, void entry, gfp_t gfp)
5431	{
5432	MA_WR_STATE(wr_mas, mas, entry);
5433
5434	mas_wr_store_setup(&wr_mas);
5435	trace_ma_write(__func__, mas, 0, entry);
5436	retry:
5437	mas_wr_store_entry(&wr_mas);
5438	if (unlikely(mas_nomem(mas, gfp)))
5439	goto retry;
5440
5441	if (unlikely(mas_is_err(mas)))
5442	return xa_err(mas->node);
5443
5444	return 0;
5445	}
5446	EXPORT_SYMBOL_GPL(mas_store_gfp);
5447
5448	/**
5449	* mas_store_prealloc() - Store a value into the tree using memory
5450	* preallocated in the maple state.
5451	* @mas: The maple state
5452	* @entry: The entry to store.
5453	*/
5454	void mas_store_prealloc(struct ma_state mas, void entry)
5455	{
5456	MA_WR_STATE(wr_mas, mas, entry);
5457
5458	mas_wr_store_setup(&wr_mas);
5459	trace_ma_write(__func__, mas, 0, entry);
5460	mas_wr_store_entry(&wr_mas);
5461	MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas));
5462	mas_destroy(mas);
5463	}
5464	EXPORT_SYMBOL_GPL(mas_store_prealloc);
5465
5466	/**
5467	* mas_preallocate() - Preallocate enough nodes for a store operation
5468	* @mas: The maple state
5469	* @entry: The entry that will be stored
5470	* @gfp: The GFP_FLAGS to use for allocations.
5471	*
5472	* Return: 0 on success, -ENOMEM if memory could not be allocated.
5473	*/
5474	int mas_preallocate(struct ma_state mas, void entry, gfp_t gfp)
5475	{
5476	MA_WR_STATE(wr_mas, mas, entry);
5477	unsigned char node_size;
5478	int request = 1;
5479	int ret;
5480
5481
5482	if (unlikely(!mas->index && mas->last == ULONG_MAX))
5483	goto ask_now;
5484
5485	mas_wr_store_setup(&wr_mas);
5486	wr_mas.content = mas_start(mas);
5487	/* Root expand */
5488	if (unlikely(mas_is_none(mas) \|\| mas_is_ptr(mas)))
5489	goto ask_now;
5490
5491	if (unlikely(!mas_wr_walk(&wr_mas))) {
5492	/* Spanning store, use worst case for now */
5493	request = 1 + mas_mt_height(mas) * 3;
5494	goto ask_now;
5495	}
5496
5497	/* At this point, we are at the leaf node that needs to be altered. */
5498	/* Exact fit, no nodes needed. */
5499	if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
5500	return 0;
5501
5502	mas_wr_end_piv(&wr_mas);
5503	node_size = mas_wr_new_end(&wr_mas);
5504
5505	/* Slot store, does not require additional nodes */
5506	if (node_size == wr_mas.node_end) {
5507	/* reuse node */
5508	if (!mt_in_rcu(mas->tree))
5509	return 0;
5510	/* shifting boundary */
5511	if (wr_mas.offset_end - mas->offset == 1)
5512	return 0;
5513	}
5514
5515	if (node_size >= mt_slots[wr_mas.type]) {
5516	/* Split, worst case for now. */
5517	request = 1 + mas_mt_height(mas) * 2;
5518	goto ask_now;
5519	}
5520
5521	/* New root needs a singe node */
5522	if (unlikely(mte_is_root(mas->node)))
5523	goto ask_now;
5524
5525	/* Potential spanning rebalance collapsing a node, use worst-case */
5526	if (node_size - 1 <= mt_min_slots[wr_mas.type])
5527	request = mas_mt_height(mas) * 2 - 1;
5528
5529	/* node store, slot store needs one node */
5530	ask_now:
5531	mas_node_count_gfp(mas, request, gfp);
5532	mas->mas_flags \|= MA_STATE_PREALLOC;
5533	if (likely(!mas_is_err(mas)))
5534	return 0;
5535
5536	mas_set_alloc_req(mas, 0);
5537	ret = xa_err(mas->node);
5538	mas_reset(mas);
5539	mas_destroy(mas);
5540	mas_reset(mas);
5541	return ret;
5542	}
5543	EXPORT_SYMBOL_GPL(mas_preallocate);
5544
5545	/*
5546	* mas_destroy() - destroy a maple state.
5547	* @mas: The maple state
5548	*
5549	* Upon completion, check the left-most node and rebalance against the node to
5550	* the right if necessary. Frees any allocated nodes associated with this maple
5551	* state.
5552	*/
5553	void mas_destroy(struct ma_state *mas)
5554	{
5555	struct maple_alloc *node;
5556	unsigned long total;
5557
5558	/*
5559	* When using mas_for_each() to insert an expected number of elements,
5560	* it is possible that the number inserted is less than the expected
5561	* number. To fix an invalid final node, a check is performed here to
5562	* rebalance the previous node with the final node.
5563	*/
5564	if (mas->mas_flags & MA_STATE_REBALANCE) {
5565	unsigned char end;
5566
5567	mas_start(mas);
5568	mtree_range_walk(mas);
5569	end = mas_data_end(mas) + 1;
5570	if (end < mt_min_slot_count(mas->node) - 1)
5571	mas_destroy_rebalance(mas, end);
5572
5573	mas->mas_flags &= ~MA_STATE_REBALANCE;
5574	}
5575	mas->mas_flags &= ~(MA_STATE_BULK\|MA_STATE_PREALLOC);
5576
5577	total = mas_allocated(mas);
5578	while (total) {
5579	node = mas->alloc;
5580	mas->alloc = node->slot[0];
5581	if (node->node_count > 1) {
5582	size_t count = node->node_count - 1;
5583
5584	mt_free_bulk(count, (void __rcu **)&node->slot[1]);
5585	total -= count;
5586	}
5587	kmem_cache_free(maple_node_cache, node);
5588	total--;
5589	}
5590
5591	mas->alloc = NULL;
5592	}
5593	EXPORT_SYMBOL_GPL(mas_destroy);
5594
5595	/*
5596	* mas_expected_entries() - Set the expected number of entries that will be inserted.
5597	* @mas: The maple state
5598	* @nr_entries: The number of expected entries.
5599	*
5600	* This will attempt to pre-allocate enough nodes to store the expected number
5601	* of entries. The allocations will occur using the bulk allocator interface
5602	* for speed. Please call mas_destroy() on the @mas after inserting the entries
5603	* to ensure any unused nodes are freed.
5604	*
5605	* Return: 0 on success, -ENOMEM if memory could not be allocated.
5606	*/
5607	int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries)
5608	{
5609	int nonleaf_cap = MAPLE_ARANGE64_SLOTS - 2;
5610	struct maple_enode *enode = mas->node;
5611	int nr_nodes;
5612	int ret;
5613
5614	/*
5615	* Sometimes it is necessary to duplicate a tree to a new tree, such as
5616	* forking a process and duplicating the VMAs from one tree to a new
5617	* tree. When such a situation arises, it is known that the new tree is
5618	* not going to be used until the entire tree is populated. For
5619	* performance reasons, it is best to use a bulk load with RCU disabled.
5620	* This allows for optimistic splitting that favours the left and reuse
5621	* of nodes during the operation.
5622	*/
5623
5624	/* Optimize splitting for bulk insert in-order */
5625	mas->mas_flags \|= MA_STATE_BULK;
5626
5627	/*
5628	* Avoid overflow, assume a gap between each entry and a trailing null.
5629	* If this is wrong, it just means allocation can happen during
5630	* insertion of entries.
5631	*/
5632	nr_nodes = max(nr_entries, nr_entries * 2 + 1);
5633	if (!mt_is_alloc(mas->tree))
5634	nonleaf_cap = MAPLE_RANGE64_SLOTS - 2;
5635
5636	/* Leaves; reduce slots to keep space for expansion */
5637	nr_nodes = DIV_ROUND_UP(nr_nodes, MAPLE_RANGE64_SLOTS - 2);
5638	/* Internal nodes */
5639	nr_nodes += DIV_ROUND_UP(nr_nodes, nonleaf_cap);
5640	/* Add working room for split (2 nodes) + new parents */
5641	mas_node_count_gfp(mas, nr_nodes + 3, GFP_KERNEL);
5642
5643	/* Detect if allocations run out */
5644	mas->mas_flags \|= MA_STATE_PREALLOC;
5645
5646	if (!mas_is_err(mas))
5647	return 0;
5648
5649	ret = xa_err(mas->node);
5650	mas->node = enode;
5651	mas_destroy(mas);
5652	return ret;
5653
5654	}
5655	EXPORT_SYMBOL_GPL(mas_expected_entries);
5656
5657	static inline bool mas_next_setup(struct ma_state *mas, unsigned long max,
5658	void **entry)
5659	{
5660	bool was_none = mas_is_none(mas);
5661
5662	if (unlikely(mas->last >= max)) {
5663	mas->node = MAS_OVERFLOW;
5664	return true;
5665	}
5666
5667	if (mas_is_active(mas))
5668	return false;
5669
5670	if (mas_is_none(mas) \|\| mas_is_paused(mas)) {
5671	mas->node = MAS_START;
5672	} else if (mas_is_overflow(mas)) {
5673	/* Overflowed before, but the max changed */
5674	mas->node = MAS_START;
5675	} else if (mas_is_underflow(mas)) {
5676	mas->node = MAS_START;
5677	*entry = mas_walk(mas);
5678	if (*entry)
5679	return true;
5680	}
5681
5682	if (mas_is_start(mas))
5683	entry = mas_walk(mas); / Retries on dead nodes handled by mas_walk */
5684
5685	if (mas_is_ptr(mas)) {
5686	*entry = NULL;
5687	if (was_none && mas->index == 0) {
5688	mas->index = mas->last = 0;
5689	return true;
5690	}
5691	mas->index = 1;
5692	mas->last = ULONG_MAX;
5693	mas->node = MAS_NONE;
5694	return true;
5695	}
5696
5697	if (mas_is_none(mas))
5698	return true;
5699
5700	return false;
5701	}
5702
5703	/**
5704	* mas_next() - Get the next entry.
5705	* @mas: The maple state
5706	* @max: The maximum index to check.
5707	*
5708	* Returns the next entry after @mas->index.
5709	* Must hold rcu_read_lock or the write lock.
5710	* Can return the zero entry.
5711	*
5712	* Return: The next entry or %NULL
5713	*/
5714	void mas_next(struct ma_state mas, unsigned long max)
5715	{
5716	void *entry = NULL;
5717
5718	if (mas_next_setup(mas, max, &entry))
5719	return entry;
5720
5721	/* Retries on dead nodes handled by mas_next_slot */
5722	return mas_next_slot(mas, max, false, true);
5723	}
5724	EXPORT_SYMBOL_GPL(mas_next);
5725
5726	/**
5727	* mas_next_range() - Advance the maple state to the next range
5728	* @mas: The maple state
5729	* @max: The maximum index to check.
5730	*
5731	* Sets @mas->index and @mas->last to the range.
5732	* Must hold rcu_read_lock or the write lock.
5733	* Can return the zero entry.
5734	*
5735	* Return: The next entry or %NULL
5736	*/
5737	void mas_next_range(struct ma_state mas, unsigned long max)
5738	{
5739	void *entry = NULL;
5740
5741	if (mas_next_setup(mas, max, &entry))
5742	return entry;
5743
5744	/* Retries on dead nodes handled by mas_next_slot */
5745	return mas_next_slot(mas, max, true, true);
5746	}
5747	EXPORT_SYMBOL_GPL(mas_next_range);
5748
5749	/**
5750	* mt_next() - get the next value in the maple tree
5751	* @mt: The maple tree
5752	* @index: The start index
5753	* @max: The maximum index to check
5754	*
5755	* Takes RCU read lock internally to protect the search, which does not
5756	* protect the returned pointer after dropping RCU read lock.
5757	* See also: Documentation/core-api/maple_tree.rst
5758	*
5759	* Return: The entry higher than @index or %NULL if nothing is found.
5760	*/
5761	void mt_next(struct maple_tree mt, unsigned long index, unsigned long max)
5762	{
5763	void *entry = NULL;
5764	MA_STATE(mas, mt, index, index);
5765
5766	rcu_read_lock();
5767	entry = mas_next(&mas, max);
5768	rcu_read_unlock();
5769	return entry;
5770	}
5771	EXPORT_SYMBOL_GPL(mt_next);
5772
5773	static inline bool mas_prev_setup(struct ma_state *mas, unsigned long min,
5774	void **entry)
5775	{
5776	if (unlikely(mas->index <= min)) {
5777	mas->node = MAS_UNDERFLOW;
5778	return true;
5779	}
5780
5781	if (mas_is_active(mas))
5782	return false;
5783
5784	if (mas_is_overflow(mas)) {
5785	mas->node = MAS_START;
5786	*entry = mas_walk(mas);
5787	if (*entry)
5788	return true;
5789	}
5790
5791	if (mas_is_none(mas) \|\| mas_is_paused(mas)) {
5792	mas->node = MAS_START;
5793	} else if (mas_is_underflow(mas)) {
5794	/* underflowed before but the min changed */
5795	mas->node = MAS_START;
5796	}
5797
5798	if (mas_is_start(mas))
5799	mas_walk(mas);
5800
5801	if (unlikely(mas_is_ptr(mas))) {
5802	if (!mas->index)
5803	goto none;
5804	mas->index = mas->last = 0;
5805	*entry = mas_root(mas);
5806	return true;
5807	}
5808
5809	if (mas_is_none(mas)) {
5810	if (mas->index) {
5811	/* Walked to out-of-range pointer? */
5812	mas->index = mas->last = 0;
5813	mas->node = MAS_ROOT;
5814	*entry = mas_root(mas);
5815	return true;
5816	}
5817	return true;
5818	}
5819
5820	return false;
5821
5822	none:
5823	mas->node = MAS_NONE;
5824	return true;
5825	}
5826
5827	/**
5828	* mas_prev() - Get the previous entry
5829	* @mas: The maple state
5830	* @min: The minimum value to check.
5831	*
5832	* Must hold rcu_read_lock or the write lock.
5833	* Will reset mas to MAS_START if the node is MAS_NONE. Will stop on not
5834	* searchable nodes.
5835	*
5836	* Return: the previous value or %NULL.
5837	*/
5838	void mas_prev(struct ma_state mas, unsigned long min)
5839	{
5840	void *entry = NULL;
5841
5842	if (mas_prev_setup(mas, min, &entry))
5843	return entry;
5844
5845	return mas_prev_slot(mas, min, false, true);
5846	}
5847	EXPORT_SYMBOL_GPL(mas_prev);
5848
5849	/**
5850	* mas_prev_range() - Advance to the previous range
5851	* @mas: The maple state
5852	* @min: The minimum value to check.
5853	*
5854	* Sets @mas->index and @mas->last to the range.
5855	* Must hold rcu_read_lock or the write lock.
5856	* Will reset mas to MAS_START if the node is MAS_NONE. Will stop on not
5857	* searchable nodes.
5858	*
5859	* Return: the previous value or %NULL.
5860	*/
5861	void mas_prev_range(struct ma_state mas, unsigned long min)
5862	{
5863	void *entry = NULL;
5864
5865	if (mas_prev_setup(mas, min, &entry))
5866	return entry;
5867
5868	return mas_prev_slot(mas, min, true, true);
5869	}
5870	EXPORT_SYMBOL_GPL(mas_prev_range);
5871
5872	/**
5873	* mt_prev() - get the previous value in the maple tree
5874	* @mt: The maple tree
5875	* @index: The start index
5876	* @min: The minimum index to check
5877	*
5878	* Takes RCU read lock internally to protect the search, which does not
5879	* protect the returned pointer after dropping RCU read lock.
5880	* See also: Documentation/core-api/maple_tree.rst
5881	*
5882	* Return: The entry before @index or %NULL if nothing is found.
5883	*/
5884	void mt_prev(struct maple_tree mt, unsigned long index, unsigned long min)
5885	{
5886	void *entry = NULL;
5887	MA_STATE(mas, mt, index, index);
5888
5889	rcu_read_lock();
5890	entry = mas_prev(&mas, min);
5891	rcu_read_unlock();
5892	return entry;
5893	}
5894	EXPORT_SYMBOL_GPL(mt_prev);
5895
5896	/**
5897	* mas_pause() - Pause a mas_find/mas_for_each to drop the lock.
5898	* @mas: The maple state to pause
5899	*
5900	* Some users need to pause a walk and drop the lock they're holding in
5901	* order to yield to a higher priority thread or carry out an operation
5902	* on an entry. Those users should call this function before they drop
5903	* the lock. It resets the @mas to be suitable for the next iteration
5904	* of the loop after the user has reacquired the lock. If most entries
5905	* found during a walk require you to call mas_pause(), the mt_for_each()
5906	* iterator may be more appropriate.
5907	*
5908	*/
5909	void mas_pause(struct ma_state *mas)
5910	{
5911	mas->node = MAS_PAUSE;
5912	}
5913	EXPORT_SYMBOL_GPL(mas_pause);
5914
5915	/**
5916	* mas_find_setup() - Internal function to set up mas_find*().
5917	* @mas: The maple state
5918	* @max: The maximum index
5919	* @entry: Pointer to the entry
5920	*
5921	* Returns: True if entry is the answer, false otherwise.
5922	*/
5923	static inline bool mas_find_setup(struct ma_state *mas, unsigned long max,
5924	void **entry)
5925	{
5926	if (mas_is_active(mas)) {
5927	if (mas->last < max)
5928	return false;
5929
5930	return true;
5931	}
5932
5933	if (mas_is_paused(mas)) {
5934	if (unlikely(mas->last >= max))
5935	return true;
5936
5937	mas->index = ++mas->last;
5938	mas->node = MAS_START;
5939	} else if (mas_is_none(mas)) {
5940	if (unlikely(mas->last >= max))
5941	return true;
5942
5943	mas->index = mas->last;
5944	mas->node = MAS_START;
5945	} else if (mas_is_overflow(mas) \|\| mas_is_underflow(mas)) {
5946	if (mas->index > max) {
5947	mas->node = MAS_OVERFLOW;
5948	return true;
5949	}
5950
5951	mas->node = MAS_START;
5952	}
5953
5954	if (mas_is_start(mas)) {
5955	/* First run or continue */
5956	if (mas->index > max)
5957	return true;
5958
5959	*entry = mas_walk(mas);
5960	if (*entry)
5961	return true;
5962
5963	}
5964
5965	if (unlikely(!mas_searchable(mas))) {
5966	if (unlikely(mas_is_ptr(mas)))
5967	goto ptr_out_of_range;
5968
5969	return true;
5970	}
5971
5972	if (mas->index == max)
5973	return true;
5974
5975	return false;
5976
5977	ptr_out_of_range:
5978	mas->node = MAS_NONE;
5979	mas->index = 1;
5980	mas->last = ULONG_MAX;
5981	return true;
5982	}
5983
5984	/**
5985	* mas_find() - On the first call, find the entry at or after mas->index up to
5986	* %max. Otherwise, find the entry after mas->index.
5987	* @mas: The maple state
5988	* @max: The maximum value to check.
5989	*
5990	* Must hold rcu_read_lock or the write lock.
5991	* If an entry exists, last and index are updated accordingly.
5992	* May set @mas->node to MAS_NONE.
5993	*
5994	* Return: The entry or %NULL.
5995	*/
5996	void mas_find(struct ma_state mas, unsigned long max)
5997	{
5998	void *entry = NULL;
5999
6000	if (mas_find_setup(mas, max, &entry))
6001	return entry;
6002
6003	/* Retries on dead nodes handled by mas_next_slot */
6004	return mas_next_slot(mas, max, false, false);
6005	}
6006	EXPORT_SYMBOL_GPL(mas_find);
6007
6008	/**
6009	* mas_find_range() - On the first call, find the entry at or after
6010	* mas->index up to %max. Otherwise, advance to the next slot mas->index.
6011	* @mas: The maple state
6012	* @max: The maximum value to check.
6013	*
6014	* Must hold rcu_read_lock or the write lock.
6015	* If an entry exists, last and index are updated accordingly.
6016	* May set @mas->node to MAS_NONE.
6017	*
6018	* Return: The entry or %NULL.
6019	*/
6020	void mas_find_range(struct ma_state mas, unsigned long max)
6021	{
6022	void *entry = NULL;
6023
6024	if (mas_find_setup(mas, max, &entry))
6025	return entry;
6026
6027	/* Retries on dead nodes handled by mas_next_slot */
6028	return mas_next_slot(mas, max, true, false);
6029	}
6030	EXPORT_SYMBOL_GPL(mas_find_range);
6031
6032	/**
6033	* mas_find_rev_setup() - Internal function to set up mas_find_*_rev()
6034	* @mas: The maple state
6035	* @min: The minimum index
6036	* @entry: Pointer to the entry
6037	*
6038	* Returns: True if entry is the answer, false otherwise.
6039	*/
6040	static inline bool mas_find_rev_setup(struct ma_state *mas, unsigned long min,
6041	void **entry)
6042	{
6043	if (mas_is_active(mas)) {
6044	if (mas->index > min)
6045	return false;
6046
6047	return true;
6048	}
6049
6050	if (mas_is_paused(mas)) {
6051	if (unlikely(mas->index <= min)) {
6052	mas->node = MAS_NONE;
6053	return true;
6054	}
6055	mas->node = MAS_START;
6056	mas->last = --mas->index;
6057	} else if (mas_is_none(mas)) {
6058	if (mas->index <= min)
6059	goto none;
6060
6061	mas->last = mas->index;
6062	mas->node = MAS_START;
6063	} else if (mas_is_underflow(mas) \|\| mas_is_overflow(mas)) {
6064	if (mas->last <= min) {
6065	mas->node = MAS_UNDERFLOW;
6066	return true;
6067	}
6068
6069	mas->node = MAS_START;
6070	}
6071
6072	if (mas_is_start(mas)) {
6073	/* First run or continue */
6074	if (mas->index < min)
6075	return true;
6076
6077	*entry = mas_walk(mas);
6078	if (*entry)
6079	return true;
6080	}
6081
6082	if (unlikely(!mas_searchable(mas))) {
6083	if (mas_is_ptr(mas))
6084	goto none;
6085
6086	if (mas_is_none(mas)) {
6087	/*
6088	* Walked to the location, and there was nothing so the
6089	* previous location is 0.
6090	*/
6091	mas->last = mas->index = 0;
6092	mas->node = MAS_ROOT;
6093	*entry = mas_root(mas);
6094	return true;
6095	}
6096	}
6097
6098	if (mas->index < min)
6099	return true;
6100
6101	return false;
6102
6103	none:
6104	mas->node = MAS_NONE;
6105	return true;
6106	}
6107
6108	/**
6109	* mas_find_rev: On the first call, find the first non-null entry at or below
6110	* mas->index down to %min. Otherwise find the first non-null entry below
6111	* mas->index down to %min.
6112	* @mas: The maple state
6113	* @min: The minimum value to check.
6114	*
6115	* Must hold rcu_read_lock or the write lock.
6116	* If an entry exists, last and index are updated accordingly.
6117	* May set @mas->node to MAS_NONE.
6118	*
6119	* Return: The entry or %NULL.
6120	*/
6121	void mas_find_rev(struct ma_state mas, unsigned long min)
6122	{
6123	void *entry = NULL;
6124
6125	if (mas_find_rev_setup(mas, min, &entry))
6126	return entry;
6127
6128	/* Retries on dead nodes handled by mas_prev_slot */
6129	return mas_prev_slot(mas, min, false, false);
6130
6131	}
6132	EXPORT_SYMBOL_GPL(mas_find_rev);
6133
6134	/**
6135	* mas_find_range_rev: On the first call, find the first non-null entry at or
6136	* below mas->index down to %min. Otherwise advance to the previous slot after
6137	* mas->index down to %min.
6138	* @mas: The maple state
6139	* @min: The minimum value to check.
6140	*
6141	* Must hold rcu_read_lock or the write lock.
6142	* If an entry exists, last and index are updated accordingly.
6143	* May set @mas->node to MAS_NONE.
6144	*
6145	* Return: The entry or %NULL.
6146	*/
6147	void mas_find_range_rev(struct ma_state mas, unsigned long min)
6148	{
6149	void *entry = NULL;
6150
6151	if (mas_find_rev_setup(mas, min, &entry))
6152	return entry;
6153
6154	/* Retries on dead nodes handled by mas_prev_slot */
6155	return mas_prev_slot(mas, min, true, false);
6156	}
6157	EXPORT_SYMBOL_GPL(mas_find_range_rev);
6158
6159	/**
6160	* mas_erase() - Find the range in which index resides and erase the entire
6161	* range.
6162	* @mas: The maple state
6163	*
6164	* Must hold the write lock.
6165	* Searches for @mas->index, sets @mas->index and @mas->last to the range and
6166	* erases that range.
6167	*
6168	* Return: the entry that was erased or %NULL, @mas->index and @mas->last are updated.
6169	*/
6170	void mas_erase(struct ma_state mas)
6171	{
6172	void *entry;
6173	MA_WR_STATE(wr_mas, mas, NULL);
6174
6175	if (mas_is_none(mas) \|\| mas_is_paused(mas))
6176	mas->node = MAS_START;
6177
6178	/* Retry unnecessary when holding the write lock. */
6179	entry = mas_state_walk(mas);
6180	if (!entry)
6181	return NULL;
6182
6183	write_retry:
6184	/* Must reset to ensure spanning writes of last slot are detected */
6185	mas_reset(mas);
6186	mas_wr_store_setup(&wr_mas);
6187	mas_wr_store_entry(&wr_mas);
6188	if (mas_nomem(mas, GFP_KERNEL))
6189	goto write_retry;
6190
6191	return entry;
6192	}
6193	EXPORT_SYMBOL_GPL(mas_erase);
6194
6195	/**
6196	* mas_nomem() - Check if there was an error allocating and do the allocation
6197	* if necessary If there are allocations, then free them.
6198	* @mas: The maple state
6199	* @gfp: The GFP_FLAGS to use for allocations
6200	* Return: true on allocation, false otherwise.
6201	*/
6202	bool mas_nomem(struct ma_state *mas, gfp_t gfp)
6203	__must_hold(mas->tree->ma_lock)
6204	{
6205	if (likely(mas->node != MA_ERROR(-ENOMEM))) {
6206	mas_destroy(mas);
6207	return false;
6208	}
6209
6210	if (gfpflags_allow_blocking(gfp) && !mt_external_lock(mas->tree)) {
6211	mtree_unlock(mas->tree);
6212	mas_alloc_nodes(mas, gfp);
6213	mtree_lock(mas->tree);
6214	} else {
6215	mas_alloc_nodes(mas, gfp);
6216	}
6217
6218	if (!mas_allocated(mas))
6219	return false;
6220
6221	mas->node = MAS_START;
6222	return true;
6223	}
6224
6225	void __init maple_tree_init(void)
6226	{
6227	maple_node_cache = kmem_cache_create("maple_node",
6228	sizeof(struct maple_node), sizeof(struct maple_node),
6229	SLAB_PANIC, NULL);
6230	}
6231
6232	/**
6233	* mtree_load() - Load a value stored in a maple tree
6234	* @mt: The maple tree
6235	* @index: The index to load
6236	*
6237	* Return: the entry or %NULL
6238	*/
6239	void mtree_load(struct maple_tree mt, unsigned long index)
6240	{
6241	MA_STATE(mas, mt, index, index);
6242	void *entry;
6243
6244	trace_ma_read(__func__, &mas);
6245	rcu_read_lock();
6246	retry:
6247	entry = mas_start(&mas);
6248	if (unlikely(mas_is_none(&mas)))
6249	goto unlock;
6250
6251	if (unlikely(mas_is_ptr(&mas))) {
6252	if (index)
6253	entry = NULL;
6254
6255	goto unlock;
6256	}
6257
6258	entry = mtree_lookup_walk(&mas);
6259	if (!entry && unlikely(mas_is_start(&mas)))
6260	goto retry;
6261	unlock:
6262	rcu_read_unlock();
6263	if (xa_is_zero(entry))
6264	return NULL;
6265
6266	return entry;
6267	}
6268	EXPORT_SYMBOL(mtree_load);
6269
6270	/**
6271	* mtree_store_range() - Store an entry at a given range.
6272	* @mt: The maple tree
6273	* @index: The start of the range
6274	* @last: The end of the range
6275	* @entry: The entry to store
6276	* @gfp: The GFP_FLAGS to use for allocations
6277	*
6278	* Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
6279	* be allocated.
6280	*/
6281	int mtree_store_range(struct maple_tree *mt, unsigned long index,
6282	unsigned long last, void *entry, gfp_t gfp)
6283	{
6284	MA_STATE(mas, mt, index, last);
6285	MA_WR_STATE(wr_mas, &mas, entry);
6286
6287	trace_ma_write(__func__, &mas, 0, entry);
6288	if (WARN_ON_ONCE(xa_is_advanced(entry)))
6289	return -EINVAL;
6290
6291	if (index > last)
6292	return -EINVAL;
6293
6294	mtree_lock(mt);
6295	retry:
6296	mas_wr_store_entry(&wr_mas);
6297	if (mas_nomem(&mas, gfp))
6298	goto retry;
6299
6300	mtree_unlock(mt);
6301	if (mas_is_err(&mas))
6302	return xa_err(mas.node);
6303
6304	return 0;
6305	}
6306	EXPORT_SYMBOL(mtree_store_range);
6307
6308	/**
6309	* mtree_store() - Store an entry at a given index.
6310	* @mt: The maple tree
6311	* @index: The index to store the value
6312	* @entry: The entry to store
6313	* @gfp: The GFP_FLAGS to use for allocations
6314	*
6315	* Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
6316	* be allocated.
6317	*/
6318	int mtree_store(struct maple_tree mt, unsigned long index, void entry,
6319	gfp_t gfp)
6320	{
6321	return mtree_store_range(mt, index, index, entry, gfp);
6322	}
6323	EXPORT_SYMBOL(mtree_store);
6324
6325	/**
6326	* mtree_insert_range() - Insert an entry at a given range if there is no value.
6327	* @mt: The maple tree
6328	* @first: The start of the range
6329	* @last: The end of the range
6330	* @entry: The entry to store
6331	* @gfp: The GFP_FLAGS to use for allocations.
6332	*
6333	* Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid
6334	* request, -ENOMEM if memory could not be allocated.
6335	*/
6336	int mtree_insert_range(struct maple_tree *mt, unsigned long first,
6337	unsigned long last, void *entry, gfp_t gfp)
6338	{
6339	MA_STATE(ms, mt, first, last);
6340
6341	if (WARN_ON_ONCE(xa_is_advanced(entry)))
6342	return -EINVAL;
6343
6344	if (first > last)
6345	return -EINVAL;
6346
6347	mtree_lock(mt);
6348	retry:
6349	mas_insert(&ms, entry);
6350	if (mas_nomem(&ms, gfp))
6351	goto retry;
6352
6353	mtree_unlock(mt);
6354	if (mas_is_err(&ms))
6355	return xa_err(ms.node);
6356
6357	return 0;
6358	}
6359	EXPORT_SYMBOL(mtree_insert_range);
6360
6361	/**
6362	* mtree_insert() - Insert an entry at a given index if there is no value.
6363	* @mt: The maple tree
6364	* @index : The index to store the value
6365	* @entry: The entry to store
6366	* @gfp: The GFP_FLAGS to use for allocations.
6367	*
6368	* Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid
6369	* request, -ENOMEM if memory could not be allocated.
6370	*/
6371	int mtree_insert(struct maple_tree mt, unsigned long index, void entry,
6372	gfp_t gfp)
6373	{
6374	return mtree_insert_range(mt, index, index, entry, gfp);
6375	}
6376	EXPORT_SYMBOL(mtree_insert);
6377
6378	int mtree_alloc_range(struct maple_tree mt, unsigned long startp,
6379	void *entry, unsigned long size, unsigned long min,
6380	unsigned long max, gfp_t gfp)
6381	{
6382	int ret = 0;
6383
6384	MA_STATE(mas, mt, 0, 0);
6385	if (!mt_is_alloc(mt))
6386	return -EINVAL;
6387
6388	if (WARN_ON_ONCE(mt_is_reserved(entry)))
6389	return -EINVAL;
6390
6391	mtree_lock(mt);
6392	retry:
6393	ret = mas_empty_area(&mas, min, max, size);
6394	if (ret)
6395	goto unlock;
6396
6397	mas_insert(&mas, entry);
6398	/*
6399	* mas_nomem() may release the lock, causing the allocated area
6400	* to be unavailable, so try to allocate a free area again.
6401	*/
6402	if (mas_nomem(&mas, gfp))
6403	goto retry;
6404
6405	if (mas_is_err(&mas))
6406	ret = xa_err(mas.node);
6407	else
6408	*startp = mas.index;
6409
6410	unlock:
6411	mtree_unlock(mt);
6412	return ret;
6413	}
6414	EXPORT_SYMBOL(mtree_alloc_range);
6415
6416	int mtree_alloc_rrange(struct maple_tree mt, unsigned long startp,
6417	void *entry, unsigned long size, unsigned long min,
6418	unsigned long max, gfp_t gfp)
6419	{
6420	int ret = 0;
6421
6422	MA_STATE(mas, mt, 0, 0);
6423	if (!mt_is_alloc(mt))
6424	return -EINVAL;
6425
6426	if (WARN_ON_ONCE(mt_is_reserved(entry)))
6427	return -EINVAL;
6428
6429	mtree_lock(mt);
6430	retry:
6431	ret = mas_empty_area_rev(&mas, min, max, size);
6432	if (ret)
6433	goto unlock;
6434
6435	mas_insert(&mas, entry);
6436	/*
6437	* mas_nomem() may release the lock, causing the allocated area
6438	* to be unavailable, so try to allocate a free area again.
6439	*/
6440	if (mas_nomem(&mas, gfp))
6441	goto retry;
6442
6443	if (mas_is_err(&mas))
6444	ret = xa_err(mas.node);
6445	else
6446	*startp = mas.index;
6447
6448	unlock:
6449	mtree_unlock(mt);
6450	return ret;
6451	}
6452	EXPORT_SYMBOL(mtree_alloc_rrange);
6453
6454	/**
6455	* mtree_erase() - Find an index and erase the entire range.
6456	* @mt: The maple tree
6457	* @index: The index to erase
6458	*
6459	* Erasing is the same as a walk to an entry then a store of a NULL to that
6460	* ENTIRE range. In fact, it is implemented as such using the advanced API.
6461	*
6462	* Return: The entry stored at the @index or %NULL
6463	*/
6464	void mtree_erase(struct maple_tree mt, unsigned long index)
6465	{
6466	void *entry = NULL;
6467
6468	MA_STATE(mas, mt, index, index);
6469	trace_ma_op(__func__, &mas);
6470
6471	mtree_lock(mt);
6472	entry = mas_erase(&mas);
6473	mtree_unlock(mt);
6474
6475	return entry;
6476	}
6477	EXPORT_SYMBOL(mtree_erase);
6478
6479	/**
6480	* __mt_destroy() - Walk and free all nodes of a locked maple tree.
6481	* @mt: The maple tree
6482	*
6483	* Note: Does not handle locking.
6484	*/
6485	void __mt_destroy(struct maple_tree *mt)
6486	{
6487	void *root = mt_root_locked(mt);
6488
6489	rcu_assign_pointer(mt->ma_root, NULL);
6490	if (xa_is_node(root))
6491	mte_destroy_walk(root, mt);
6492
6493	mt->ma_flags = 0;
6494	}
6495	EXPORT_SYMBOL_GPL(__mt_destroy);
6496
6497	/**
6498	* mtree_destroy() - Destroy a maple tree
6499	* @mt: The maple tree
6500	*
6501	* Frees all resources used by the tree. Handles locking.
6502	*/
6503	void mtree_destroy(struct maple_tree *mt)
6504	{
6505	mtree_lock(mt);
6506	__mt_destroy(mt);
6507	mtree_unlock(mt);
6508	}
6509	EXPORT_SYMBOL(mtree_destroy);
6510
6511	/**
6512	* mt_find() - Search from the start up until an entry is found.
6513	* @mt: The maple tree
6514	* @index: Pointer which contains the start location of the search
6515	* @max: The maximum value of the search range
6516	*
6517	* Takes RCU read lock internally to protect the search, which does not
6518	* protect the returned pointer after dropping RCU read lock.
6519	* See also: Documentation/core-api/maple_tree.rst
6520	*
6521	* In case that an entry is found @index is updated to point to the next
6522	* possible entry independent whether the found entry is occupying a
6523	* single index or a range if indices.
6524	*
6525	* Return: The entry at or after the @index or %NULL
6526	*/
6527	void mt_find(struct maple_tree mt, unsigned long *index, unsigned long max)
6528	{
6529	MA_STATE(mas, mt, index, index);
6530	void *entry;
6531	#ifdef CONFIG_DEBUG_MAPLE_TREE
6532	unsigned long copy = *index;
6533	#endif
6534
6535	trace_ma_read(__func__, &mas);
6536
6537	if ((*index) > max)
6538	return NULL;
6539
6540	rcu_read_lock();
6541	retry:
6542	entry = mas_state_walk(&mas);
6543	if (mas_is_start(&mas))
6544	goto retry;
6545
6546	if (unlikely(xa_is_zero(entry)))
6547	entry = NULL;
6548
6549	if (entry)
6550	goto unlock;
6551
6552	while (mas_searchable(&mas) && (mas.last < max)) {
6553	entry = mas_next_entry(&mas, max);
6554	if (likely(entry && !xa_is_zero(entry)))
6555	break;
6556	}
6557
6558	if (unlikely(xa_is_zero(entry)))
6559	entry = NULL;
6560	unlock:
6561	rcu_read_unlock();
6562	if (likely(entry)) {
6563	*index = mas.last + 1;
6564	#ifdef CONFIG_DEBUG_MAPLE_TREE
6565	if (MT_WARN_ON(mt, (index) && ((index) <= copy)))
6566	pr_err("index not increased! %lx <= %lx\n",
6567	*index, copy);
6568	#endif
6569	}
6570
6571	return entry;
6572	}
6573	EXPORT_SYMBOL(mt_find);
6574
6575	/**
6576	* mt_find_after() - Search from the start up until an entry is found.
6577	* @mt: The maple tree
6578	* @index: Pointer which contains the start location of the search
6579	* @max: The maximum value to check
6580	*
6581	* Same as mt_find() except that it checks @index for 0 before
6582	* searching. If @index == 0, the search is aborted. This covers a wrap
6583	* around of @index to 0 in an iterator loop.
6584	*
6585	* Return: The entry at or after the @index or %NULL
6586	*/
6587	void mt_find_after(struct maple_tree mt, unsigned long *index,
6588	unsigned long max)
6589	{
6590	if (!(*index))
6591	return NULL;
6592
6593	return mt_find(mt, index, max);
6594	}
6595	EXPORT_SYMBOL(mt_find_after);
6596
6597	#ifdef CONFIG_DEBUG_MAPLE_TREE
6598	atomic_t maple_tree_tests_run;
6599	EXPORT_SYMBOL_GPL(maple_tree_tests_run);
6600	atomic_t maple_tree_tests_passed;
6601	EXPORT_SYMBOL_GPL(maple_tree_tests_passed);
6602
6603	#ifndef __KERNEL__
6604	extern void kmem_cache_set_non_kernel(struct kmem_cache *, unsigned int);
6605	void mt_set_non_kernel(unsigned int val)
6606	{
6607	kmem_cache_set_non_kernel(maple_node_cache, val);
6608	}
6609
6610	extern unsigned long kmem_cache_get_alloc(struct kmem_cache *);
6611	unsigned long mt_get_alloc_size(void)
6612	{
6613	return kmem_cache_get_alloc(maple_node_cache);
6614	}
6615
6616	extern void kmem_cache_zero_nr_tallocated(struct kmem_cache *);
6617	void mt_zero_nr_tallocated(void)
6618	{
6619	kmem_cache_zero_nr_tallocated(maple_node_cache);
6620	}
6621
6622	extern unsigned int kmem_cache_nr_tallocated(struct kmem_cache *);
6623	unsigned int mt_nr_tallocated(void)
6624	{
6625	return kmem_cache_nr_tallocated(maple_node_cache);
6626	}
6627
6628	extern unsigned int kmem_cache_nr_allocated(struct kmem_cache *);
6629	unsigned int mt_nr_allocated(void)
6630	{
6631	return kmem_cache_nr_allocated(maple_node_cache);
6632	}
6633
6634	/*
6635	* mas_dead_node() - Check if the maple state is pointing to a dead node.
6636	* @mas: The maple state
6637	* @index: The index to restore in @mas.
6638	*
6639	* Used in test code.
6640	* Return: 1 if @mas has been reset to MAS_START, 0 otherwise.
6641	*/
6642	static inline int mas_dead_node(struct ma_state *mas, unsigned long index)
6643	{
6644	if (unlikely(!mas_searchable(mas) \|\| mas_is_start(mas)))
6645	return 0;
6646
6647	if (likely(!mte_dead_node(mas->node)))
6648	return 0;
6649
6650	mas_rewalk(mas, index);
6651	return 1;
6652	}
6653
6654	void mt_cache_shrink(void)
6655	{
6656	}
6657	#else
6658	/*
6659	* mt_cache_shrink() - For testing, don't use this.
6660	*
6661	* Certain testcases can trigger an OOM when combined with other memory
6662	* debugging configuration options. This function is used to reduce the
6663	* possibility of an out of memory even due to kmem_cache objects remaining
6664	* around for longer than usual.
6665	*/
6666	void mt_cache_shrink(void)
6667	{
6668	kmem_cache_shrink(maple_node_cache);
6669
6670	}
6671	EXPORT_SYMBOL_GPL(mt_cache_shrink);
6672
6673	#endif /* not defined __KERNEL__ */
6674	/*
6675	* mas_get_slot() - Get the entry in the maple state node stored at @offset.
6676	* @mas: The maple state
6677	* @offset: The offset into the slot array to fetch.
6678	*
6679	* Return: The entry stored at @offset.
6680	*/
6681	static inline struct maple_enode mas_get_slot(struct ma_state mas,
6682	unsigned char offset)
6683	{
6684	return mas_slot(mas, ma_slots(mas_mn(mas), mte_node_type(mas->node)),
6685	offset);
6686	}
6687
6688	/* Depth first search, post-order */
6689	static void mas_dfs_postorder(struct ma_state *mas, unsigned long max)
6690	{
6691
6692	struct maple_enode p = MAS_NONE, mn = mas->node;
6693	unsigned long p_min, p_max;
6694
6695	mas_next_node(mas, mas_mn(mas), max);
6696	if (!mas_is_none(mas))
6697	return;
6698
6699	if (mte_is_root(mn))
6700	return;
6701
6702	mas->node = mn;
6703	mas_ascend(mas);
6704	do {
6705	p = mas->node;
6706	p_min = mas->min;
6707	p_max = mas->max;
6708	mas_prev_node(mas, 0);
6709	} while (!mas_is_none(mas));
6710
6711	mas->node = p;
6712	mas->max = p_max;
6713	mas->min = p_min;
6714	}
6715
6716	/* Tree validations */
6717	static void mt_dump_node(const struct maple_tree mt, void entry,
6718	unsigned long min, unsigned long max, unsigned int depth,
6719	enum mt_dump_format format);
6720	static void mt_dump_range(unsigned long min, unsigned long max,
6721	unsigned int depth, enum mt_dump_format format)
6722	{
6723	static const char spaces[] = " ";
6724
6725	switch(format) {
6726	case mt_dump_hex:
6727	if (min == max)
6728	pr_info("%.s%lx: ", depth 2, spaces, min);
6729	else
6730	pr_info("%.s%lx-%lx: ", depth 2, spaces, min, max);
6731	break;
6732	default:
6733	case mt_dump_dec:
6734	if (min == max)
6735	pr_info("%.s%lu: ", depth 2, spaces, min);
6736	else
6737	pr_info("%.s%lu-%lu: ", depth 2, spaces, min, max);
6738	}
6739	}
6740
6741	static void mt_dump_entry(void *entry, unsigned long min, unsigned long max,
6742	unsigned int depth, enum mt_dump_format format)
6743	{
6744	mt_dump_range(min, max, depth, format);
6745
6746	if (xa_is_value(entry))
6747	pr_cont("value %ld (0x%lx) [%p]\n", xa_to_value(entry),
6748	xa_to_value(entry), entry);
6749	else if (xa_is_zero(entry))
6750	pr_cont("zero (%ld)\n", xa_to_internal(entry));
6751	else if (mt_is_reserved(entry))
6752	pr_cont("UNKNOWN ENTRY (%p)\n", entry);
6753	else
6754	pr_cont("%p\n", entry);
6755	}
6756
6757	static void mt_dump_range64(const struct maple_tree mt, void entry,
6758	unsigned long min, unsigned long max, unsigned int depth,
6759	enum mt_dump_format format)
6760	{
6761	struct maple_range_64 *node = &mte_to_node(entry)->mr64;
6762	bool leaf = mte_is_leaf(entry);
6763	unsigned long first = min;
6764	int i;
6765
6766	pr_cont(" contents: ");
6767	for (i = 0; i < MAPLE_RANGE64_SLOTS - 1; i++) {
6768	switch(format) {
6769	case mt_dump_hex:
6770	pr_cont("%p %lX ", node->slot[i], node->pivot[i]);
6771	break;
6772	default:
6773	case mt_dump_dec:
6774	pr_cont("%p %lu ", node->slot[i], node->pivot[i]);
6775	}
6776	}
6777	pr_cont("%p\n", node->slot[i]);
6778	for (i = 0; i < MAPLE_RANGE64_SLOTS; i++) {
6779	unsigned long last = max;
6780
6781	if (i < (MAPLE_RANGE64_SLOTS - 1))
6782	last = node->pivot[i];
6783	else if (!node->slot[i] && max != mt_node_max(entry))
6784	break;
6785	if (last == 0 && i > 0)
6786	break;
6787	if (leaf)
6788	mt_dump_entry(mt_slot(mt, node->slot, i),
6789	first, last, depth + 1, format);
6790	else if (node->slot[i])
6791	mt_dump_node(mt, mt_slot(mt, node->slot, i),
6792	first, last, depth + 1, format);
6793
6794	if (last == max)
6795	break;
6796	if (last > max) {
6797	switch(format) {
6798	case mt_dump_hex:
6799	pr_err("node %p last (%lx) > max (%lx) at pivot %d!\n",
6800	node, last, max, i);
6801	break;
6802	default:
6803	case mt_dump_dec:
6804	pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n",
6805	node, last, max, i);
6806	}
6807	}
6808	first = last + 1;
6809	}
6810	}
6811
6812	static void mt_dump_arange64(const struct maple_tree mt, void entry,
6813	unsigned long min, unsigned long max, unsigned int depth,
6814	enum mt_dump_format format)
6815	{
6816	struct maple_arange_64 *node = &mte_to_node(entry)->ma64;
6817	bool leaf = mte_is_leaf(entry);
6818	unsigned long first = min;
6819	int i;
6820
6821	pr_cont(" contents: ");
6822	for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) {
6823	switch (format) {
6824	case mt_dump_hex:
6825	pr_cont("%lx ", node->gap[i]);
6826	break;
6827	default:
6828	case mt_dump_dec:
6829	pr_cont("%lu ", node->gap[i]);
6830	}
6831	}
6832	pr_cont("\| %02X %02X\| ", node->meta.end, node->meta.gap);
6833	for (i = 0; i < MAPLE_ARANGE64_SLOTS - 1; i++) {
6834	switch (format) {
6835	case mt_dump_hex:
6836	pr_cont("%p %lX ", node->slot[i], node->pivot[i]);
6837	break;
6838	default:
6839	case mt_dump_dec:
6840	pr_cont("%p %lu ", node->slot[i], node->pivot[i]);
6841	}
6842	}
6843	pr_cont("%p\n", node->slot[i]);
6844	for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) {
6845	unsigned long last = max;
6846
6847	if (i < (MAPLE_ARANGE64_SLOTS - 1))
6848	last = node->pivot[i];
6849	else if (!node->slot[i])
6850	break;
6851	if (last == 0 && i > 0)
6852	break;
6853	if (leaf)
6854	mt_dump_entry(mt_slot(mt, node->slot, i),
6855	first, last, depth + 1, format);
6856	else if (node->slot[i])
6857	mt_dump_node(mt, mt_slot(mt, node->slot, i),
6858	first, last, depth + 1, format);
6859
6860	if (last == max)
6861	break;
6862	if (last > max) {
6863	pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n",
6864	node, last, max, i);
6865	break;
6866	}
6867	first = last + 1;
6868	}
6869	}
6870
6871	static void mt_dump_node(const struct maple_tree mt, void entry,
6872	unsigned long min, unsigned long max, unsigned int depth,
6873	enum mt_dump_format format)
6874	{
6875	struct maple_node *node = mte_to_node(entry);
6876	unsigned int type = mte_node_type(entry);
6877	unsigned int i;
6878
6879	mt_dump_range(min, max, depth, format);
6880
6881	pr_cont("node %p depth %d type %d parent %p", node, depth, type,
6882	node ? node->parent : NULL);
6883	switch (type) {
6884	case maple_dense:
6885	pr_cont("\n");
6886	for (i = 0; i < MAPLE_NODE_SLOTS; i++) {
6887	if (min + i > max)
6888	pr_cont("OUT OF RANGE: ");
6889	mt_dump_entry(mt_slot(mt, node->slot, i),
6890	min + i, min + i, depth, format);
6891	}
6892	break;
6893	case maple_leaf_64:
6894	case maple_range_64:
6895	mt_dump_range64(mt, entry, min, max, depth, format);
6896	break;
6897	case maple_arange_64:
6898	mt_dump_arange64(mt, entry, min, max, depth, format);
6899	break;
6900
6901	default:
6902	pr_cont(" UNKNOWN TYPE\n");
6903	}
6904	}
6905
6906	void mt_dump(const struct maple_tree *mt, enum mt_dump_format format)
6907	{
6908	void *entry = rcu_dereference_check(mt->ma_root, mt_locked(mt));
6909
6910	pr_info("maple_tree(%p) flags %X, height %u root %p\n",
6911	mt, mt->ma_flags, mt_height(mt), entry);
6912	if (!xa_is_node(entry))
6913	mt_dump_entry(entry, 0, 0, 0, format);
6914	else if (entry)
6915	mt_dump_node(mt, entry, 0, mt_node_max(entry), 0, format);
6916	}
6917	EXPORT_SYMBOL_GPL(mt_dump);
6918
6919	/*
6920	* Calculate the maximum gap in a node and check if that's what is reported in
6921	* the parent (unless root).
6922	*/
6923	static void mas_validate_gaps(struct ma_state *mas)
6924	{
6925	struct maple_enode *mte = mas->node;
6926	struct maple_node p_mn, node = mte_to_node(mte);
6927	enum maple_type mt = mte_node_type(mas->node);
6928	unsigned long gap = 0, max_gap = 0;
6929	unsigned long p_end, p_start = mas->min;
6930	unsigned char p_slot, offset;
6931	unsigned long *gaps = NULL;
6932	unsigned long *pivots = ma_pivots(node, mt);
6933	unsigned int i;
6934
6935	if (ma_is_dense(mt)) {
6936	for (i = 0; i < mt_slot_count(mte); i++) {
6937	if (mas_get_slot(mas, i)) {
6938	if (gap > max_gap)
6939	max_gap = gap;
6940	gap = 0;
6941	continue;
6942	}
6943	gap++;
6944	}
6945	goto counted;
6946	}
6947
6948	gaps = ma_gaps(node, mt);
6949	for (i = 0; i < mt_slot_count(mte); i++) {
6950	p_end = mas_safe_pivot(mas, pivots, i, mt);
6951
6952	if (!gaps) {
6953	if (!mas_get_slot(mas, i))
6954	gap = p_end - p_start + 1;
6955	} else {
6956	void *entry = mas_get_slot(mas, i);
6957
6958	gap = gaps[i];
6959	MT_BUG_ON(mas->tree, !entry);
6960
6961	if (gap > p_end - p_start + 1) {
6962	pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n",
6963	mas_mn(mas), i, gap, p_end, p_start,
6964	p_end - p_start + 1);
6965	MT_BUG_ON(mas->tree, gap > p_end - p_start + 1);
6966	}
6967	}
6968
6969	if (gap > max_gap)
6970	max_gap = gap;
6971
6972	p_start = p_end + 1;
6973	if (p_end >= mas->max)
6974	break;
6975	}
6976
6977	counted:
6978	if (mt == maple_arange_64) {
6979	offset = ma_meta_gap(node, mt);
6980	if (offset > i) {
6981	pr_err("gap offset %p[%u] is invalid\n", node, offset);
6982	MT_BUG_ON(mas->tree, 1);
6983	}
6984
6985	if (gaps[offset] != max_gap) {
6986	pr_err("gap %p[%u] is not the largest gap %lu\n",
6987	node, offset, max_gap);
6988	MT_BUG_ON(mas->tree, 1);
6989	}
6990
6991	MT_BUG_ON(mas->tree, !gaps);
6992	for (i++ ; i < mt_slot_count(mte); i++) {
6993	if (gaps[i] != 0) {
6994	pr_err("gap %p[%u] beyond node limit != 0\n",
6995	node, i);
6996	MT_BUG_ON(mas->tree, 1);
6997	}
6998	}
6999	}
7000
7001	if (mte_is_root(mte))
7002	return;
7003
7004	p_slot = mte_parent_slot(mas->node);
7005	p_mn = mte_parent(mte);
7006	MT_BUG_ON(mas->tree, max_gap > mas->max);
7007	if (ma_gaps(p_mn, mas_parent_type(mas, mte))[p_slot] != max_gap) {
7008	pr_err("gap %p[%u] != %lu\n", p_mn, p_slot, max_gap);
7009	mt_dump(mas->tree, mt_dump_hex);
7010	MT_BUG_ON(mas->tree, 1);
7011	}
7012	}
7013
7014	static void mas_validate_parent_slot(struct ma_state *mas)
7015	{
7016	struct maple_node *parent;
7017	struct maple_enode *node;
7018	enum maple_type p_type;
7019	unsigned char p_slot;
7020	void __rcu **slots;
7021	int i;
7022
7023	if (mte_is_root(mas->node))
7024	return;
7025
7026	p_slot = mte_parent_slot(mas->node);
7027	p_type = mas_parent_type(mas, mas->node);
7028	parent = mte_parent(mas->node);
7029	slots = ma_slots(parent, p_type);
7030	MT_BUG_ON(mas->tree, mas_mn(mas) == parent);
7031
7032	/* Check prev/next parent slot for duplicate node entry */
7033
7034	for (i = 0; i < mt_slots[p_type]; i++) {
7035	node = mas_slot(mas, slots, i);
7036	if (i == p_slot) {
7037	if (node != mas->node)
7038	pr_err("parent %p[%u] does not have %p\n",
7039	parent, i, mas_mn(mas));
7040	MT_BUG_ON(mas->tree, node != mas->node);
7041	} else if (node == mas->node) {
7042	pr_err("Invalid child %p at parent %p[%u] p_slot %u\n",
7043	mas_mn(mas), parent, i, p_slot);
7044	MT_BUG_ON(mas->tree, node == mas->node);
7045	}
7046	}
7047	}
7048
7049	static void mas_validate_child_slot(struct ma_state *mas)
7050	{
7051	enum maple_type type = mte_node_type(mas->node);
7052	void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
7053	unsigned long *pivots = ma_pivots(mte_to_node(mas->node), type);
7054	struct maple_enode *child;
7055	unsigned char i;
7056
7057	if (mte_is_leaf(mas->node))
7058	return;
7059
7060	for (i = 0; i < mt_slots[type]; i++) {
7061	child = mas_slot(mas, slots, i);
7062
7063	if (!child) {
7064	pr_err("Non-leaf node lacks child at %p[%u]\n",
7065	mas_mn(mas), i);
7066	MT_BUG_ON(mas->tree, 1);
7067	}
7068
7069	if (mte_parent_slot(child) != i) {
7070	pr_err("Slot error at %p[%u]: child %p has pslot %u\n",
7071	mas_mn(mas), i, mte_to_node(child),
7072	mte_parent_slot(child));
7073	MT_BUG_ON(mas->tree, 1);
7074	}
7075
7076	if (mte_parent(child) != mte_to_node(mas->node)) {
7077	pr_err("child %p has parent %p not %p\n",
7078	mte_to_node(child), mte_parent(child),
7079	mte_to_node(mas->node));
7080	MT_BUG_ON(mas->tree, 1);
7081	}
7082
7083	if (i < mt_pivots[type] && pivots[i] == mas->max)
7084	break;
7085	}
7086	}
7087
7088	/*
7089	* Validate all pivots are within mas->min and mas->max, check metadata ends
7090	* where the maximum ends and ensure there is no slots or pivots set outside of
7091	* the end of the data.
7092	*/
7093	static void mas_validate_limits(struct ma_state *mas)
7094	{
7095	int i;
7096	unsigned long prev_piv = 0;
7097	enum maple_type type = mte_node_type(mas->node);
7098	void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
7099	unsigned long *pivots = ma_pivots(mas_mn(mas), type);
7100
7101	for (i = 0; i < mt_slots[type]; i++) {
7102	unsigned long piv;
7103
7104	piv = mas_safe_pivot(mas, pivots, i, type);
7105
7106	if (!piv && (i != 0)) {
7107	pr_err("Missing node limit pivot at %p[%u]",
7108	mas_mn(mas), i);
7109	MAS_WARN_ON(mas, 1);
7110	}
7111
7112	if (prev_piv > piv) {
7113	pr_err("%p[%u] piv %lu < prev_piv %lu\n",
7114	mas_mn(mas), i, piv, prev_piv);
7115	MAS_WARN_ON(mas, piv < prev_piv);
7116	}
7117
7118	if (piv < mas->min) {
7119	pr_err("%p[%u] %lu < %lu\n", mas_mn(mas), i,
7120	piv, mas->min);
7121	MAS_WARN_ON(mas, piv < mas->min);
7122	}
7123	if (piv > mas->max) {
7124	pr_err("%p[%u] %lu > %lu\n", mas_mn(mas), i,
7125	piv, mas->max);
7126	MAS_WARN_ON(mas, piv > mas->max);
7127	}
7128	prev_piv = piv;
7129	if (piv == mas->max)
7130	break;
7131	}
7132
7133	if (mas_data_end(mas) != i) {
7134	pr_err("node%p: data_end %u != the last slot offset %u\n",
7135	mas_mn(mas), mas_data_end(mas), i);
7136	MT_BUG_ON(mas->tree, 1);
7137	}
7138
7139	for (i += 1; i < mt_slots[type]; i++) {
7140	void *entry = mas_slot(mas, slots, i);
7141
7142	if (entry && (i != mt_slots[type] - 1)) {
7143	pr_err("%p[%u] should not have entry %p\n", mas_mn(mas),
7144	i, entry);
7145	MT_BUG_ON(mas->tree, entry != NULL);
7146	}
7147
7148	if (i < mt_pivots[type]) {
7149	unsigned long piv = pivots[i];
7150
7151	if (!piv)
7152	continue;
7153
7154	pr_err("%p[%u] should not have piv %lu\n",
7155	mas_mn(mas), i, piv);
7156	MAS_WARN_ON(mas, i < mt_pivots[type] - 1);
7157	}
7158	}
7159	}
7160
7161	static void mt_validate_nulls(struct maple_tree *mt)
7162	{
7163	void entry, last = (void *)1;
7164	unsigned char offset = 0;
7165	void __rcu **slots;
7166	MA_STATE(mas, mt, 0, 0);
7167
7168	mas_start(&mas);
7169	if (mas_is_none(&mas) \|\| (mas.node == MAS_ROOT))
7170	return;
7171
7172	while (!mte_is_leaf(mas.node))
7173	mas_descend(&mas);
7174
7175	slots = ma_slots(mte_to_node(mas.node), mte_node_type(mas.node));
7176	do {
7177	entry = mas_slot(&mas, slots, offset);
7178	if (!last && !entry) {
7179	pr_err("Sequential nulls end at %p[%u]\n",
7180	mas_mn(&mas), offset);
7181	}
7182	MT_BUG_ON(mt, !last && !entry);
7183	last = entry;
7184	if (offset == mas_data_end(&mas)) {
7185	mas_next_node(&mas, mas_mn(&mas), ULONG_MAX);
7186	if (mas_is_none(&mas))
7187	return;
7188	offset = 0;
7189	slots = ma_slots(mte_to_node(mas.node),
7190	mte_node_type(mas.node));
7191	} else {
7192	offset++;
7193	}
7194
7195	} while (!mas_is_none(&mas));
7196	}
7197
7198	/*
7199	* validate a maple tree by checking:
7200	* 1. The limits (pivots are within mas->min to mas->max)
7201	* 2. The gap is correctly set in the parents
7202	*/
7203	void mt_validate(struct maple_tree *mt)
7204	{
7205	unsigned char end;
7206
7207	MA_STATE(mas, mt, 0, 0);
7208	rcu_read_lock();
7209	mas_start(&mas);
7210	if (!mas_searchable(&mas))
7211	goto done;
7212
7213	while (!mte_is_leaf(mas.node))
7214	mas_descend(&mas);
7215
7216	while (!mas_is_none(&mas)) {
7217	MAS_WARN_ON(&mas, mte_dead_node(mas.node));
7218	end = mas_data_end(&mas);
7219	if (MAS_WARN_ON(&mas, (end < mt_min_slot_count(mas.node)) &&
7220	(mas.max != ULONG_MAX))) {
7221	pr_err("Invalid size %u of %p\n", end, mas_mn(&mas));
7222	}
7223
7224	mas_validate_parent_slot(&mas);
7225	mas_validate_limits(&mas);
7226	mas_validate_child_slot(&mas);
7227	if (mt_is_alloc(mt))
7228	mas_validate_gaps(&mas);
7229	mas_dfs_postorder(&mas, ULONG_MAX);
7230	}
7231	mt_validate_nulls(mt);
7232	done:
7233	rcu_read_unlock();
7234
7235	}
7236	EXPORT_SYMBOL_GPL(mt_validate);
7237
7238	void mas_dump(const struct ma_state *mas)
7239	{
7240	pr_err("MAS: tree=%p enode=%p ", mas->tree, mas->node);
7241	if (mas_is_none(mas))
7242	pr_err("(MAS_NONE) ");
7243	else if (mas_is_ptr(mas))
7244	pr_err("(MAS_ROOT) ");
7245	else if (mas_is_start(mas))
7246	pr_err("(MAS_START) ");
7247	else if (mas_is_paused(mas))
7248	pr_err("(MAS_PAUSED) ");
7249
7250	pr_err("[%u] index=%lx last=%lx\n", mas->offset, mas->index, mas->last);
7251	pr_err(" min=%lx max=%lx alloc=%p, depth=%u, flags=%x\n",
7252	mas->min, mas->max, mas->alloc, mas->depth, mas->mas_flags);
7253	if (mas->index > mas->last)
7254	pr_err("Check index & last\n");
7255	}
7256	EXPORT_SYMBOL_GPL(mas_dump);
7257
7258	void mas_wr_dump(const struct ma_wr_state *wr_mas)
7259	{
7260	pr_err("WR_MAS: node=%p r_min=%lx r_max=%lx\n",
7261	wr_mas->node, wr_mas->r_min, wr_mas->r_max);
7262	pr_err(" type=%u off_end=%u, node_end=%u, end_piv=%lx\n",
7263	wr_mas->type, wr_mas->offset_end, wr_mas->node_end,
7264	wr_mas->end_piv);
7265	}
7266	EXPORT_SYMBOL_GPL(mas_wr_dump);
7267
7268	#endif /* CONFIG_DEBUG_MAPLE_TREE */