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f8d5d0cc MW |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * XArray implementation | |
4 | * Copyright (c) 2017 Microsoft Corporation | |
5 | * Author: Matthew Wilcox <willy@infradead.org> | |
6 | */ | |
7 | ||
9b89a035 | 8 | #include <linux/bitmap.h> |
f8d5d0cc | 9 | #include <linux/export.h> |
58d6ea30 MW |
10 | #include <linux/list.h> |
11 | #include <linux/slab.h> | |
f8d5d0cc MW |
12 | #include <linux/xarray.h> |
13 | ||
14 | /* | |
15 | * Coding conventions in this file: | |
16 | * | |
17 | * @xa is used to refer to the entire xarray. | |
18 | * @xas is the 'xarray operation state'. It may be either a pointer to | |
19 | * an xa_state, or an xa_state stored on the stack. This is an unfortunate | |
20 | * ambiguity. | |
21 | * @index is the index of the entry being operated on | |
22 | * @mark is an xa_mark_t; a small number indicating one of the mark bits. | |
23 | * @node refers to an xa_node; usually the primary one being operated on by | |
24 | * this function. | |
25 | * @offset is the index into the slots array inside an xa_node. | |
26 | * @parent refers to the @xa_node closer to the head than @node. | |
27 | * @entry refers to something stored in a slot in the xarray | |
28 | */ | |
29 | ||
58d6ea30 MW |
30 | static inline unsigned int xa_lock_type(const struct xarray *xa) |
31 | { | |
32 | return (__force unsigned int)xa->xa_flags & 3; | |
33 | } | |
34 | ||
35 | static inline void xas_lock_type(struct xa_state *xas, unsigned int lock_type) | |
36 | { | |
37 | if (lock_type == XA_LOCK_IRQ) | |
38 | xas_lock_irq(xas); | |
39 | else if (lock_type == XA_LOCK_BH) | |
40 | xas_lock_bh(xas); | |
41 | else | |
42 | xas_lock(xas); | |
43 | } | |
44 | ||
45 | static inline void xas_unlock_type(struct xa_state *xas, unsigned int lock_type) | |
46 | { | |
47 | if (lock_type == XA_LOCK_IRQ) | |
48 | xas_unlock_irq(xas); | |
49 | else if (lock_type == XA_LOCK_BH) | |
50 | xas_unlock_bh(xas); | |
51 | else | |
52 | xas_unlock(xas); | |
53 | } | |
54 | ||
371c752d MW |
55 | static inline bool xa_track_free(const struct xarray *xa) |
56 | { | |
57 | return xa->xa_flags & XA_FLAGS_TRACK_FREE; | |
58 | } | |
59 | ||
9b89a035 MW |
60 | static inline void xa_mark_set(struct xarray *xa, xa_mark_t mark) |
61 | { | |
62 | if (!(xa->xa_flags & XA_FLAGS_MARK(mark))) | |
63 | xa->xa_flags |= XA_FLAGS_MARK(mark); | |
64 | } | |
65 | ||
66 | static inline void xa_mark_clear(struct xarray *xa, xa_mark_t mark) | |
67 | { | |
68 | if (xa->xa_flags & XA_FLAGS_MARK(mark)) | |
69 | xa->xa_flags &= ~(XA_FLAGS_MARK(mark)); | |
70 | } | |
71 | ||
72 | static inline unsigned long *node_marks(struct xa_node *node, xa_mark_t mark) | |
73 | { | |
74 | return node->marks[(__force unsigned)mark]; | |
75 | } | |
76 | ||
77 | static inline bool node_get_mark(struct xa_node *node, | |
78 | unsigned int offset, xa_mark_t mark) | |
79 | { | |
80 | return test_bit(offset, node_marks(node, mark)); | |
81 | } | |
82 | ||
83 | /* returns true if the bit was set */ | |
84 | static inline bool node_set_mark(struct xa_node *node, unsigned int offset, | |
85 | xa_mark_t mark) | |
86 | { | |
87 | return __test_and_set_bit(offset, node_marks(node, mark)); | |
88 | } | |
89 | ||
90 | /* returns true if the bit was set */ | |
91 | static inline bool node_clear_mark(struct xa_node *node, unsigned int offset, | |
92 | xa_mark_t mark) | |
93 | { | |
94 | return __test_and_clear_bit(offset, node_marks(node, mark)); | |
95 | } | |
96 | ||
97 | static inline bool node_any_mark(struct xa_node *node, xa_mark_t mark) | |
98 | { | |
99 | return !bitmap_empty(node_marks(node, mark), XA_CHUNK_SIZE); | |
100 | } | |
101 | ||
371c752d MW |
102 | static inline void node_mark_all(struct xa_node *node, xa_mark_t mark) |
103 | { | |
104 | bitmap_fill(node_marks(node, mark), XA_CHUNK_SIZE); | |
105 | } | |
106 | ||
58d6ea30 MW |
107 | #define mark_inc(mark) do { \ |
108 | mark = (__force xa_mark_t)((__force unsigned)(mark) + 1); \ | |
109 | } while (0) | |
110 | ||
111 | /* | |
112 | * xas_squash_marks() - Merge all marks to the first entry | |
113 | * @xas: Array operation state. | |
114 | * | |
115 | * Set a mark on the first entry if any entry has it set. Clear marks on | |
116 | * all sibling entries. | |
117 | */ | |
118 | static void xas_squash_marks(const struct xa_state *xas) | |
119 | { | |
120 | unsigned int mark = 0; | |
121 | unsigned int limit = xas->xa_offset + xas->xa_sibs + 1; | |
122 | ||
123 | if (!xas->xa_sibs) | |
124 | return; | |
125 | ||
126 | do { | |
127 | unsigned long *marks = xas->xa_node->marks[mark]; | |
128 | if (find_next_bit(marks, limit, xas->xa_offset + 1) == limit) | |
129 | continue; | |
130 | __set_bit(xas->xa_offset, marks); | |
131 | bitmap_clear(marks, xas->xa_offset + 1, xas->xa_sibs); | |
132 | } while (mark++ != (__force unsigned)XA_MARK_MAX); | |
133 | } | |
134 | ||
ad3d6c72 MW |
135 | /* extracts the offset within this node from the index */ |
136 | static unsigned int get_offset(unsigned long index, struct xa_node *node) | |
137 | { | |
138 | return (index >> node->shift) & XA_CHUNK_MASK; | |
139 | } | |
140 | ||
b803b428 MW |
141 | static void xas_set_offset(struct xa_state *xas) |
142 | { | |
143 | xas->xa_offset = get_offset(xas->xa_index, xas->xa_node); | |
144 | } | |
145 | ||
ad3d6c72 MW |
146 | /* move the index either forwards (find) or backwards (sibling slot) */ |
147 | static void xas_move_index(struct xa_state *xas, unsigned long offset) | |
148 | { | |
149 | unsigned int shift = xas->xa_node->shift; | |
150 | xas->xa_index &= ~XA_CHUNK_MASK << shift; | |
151 | xas->xa_index += offset << shift; | |
152 | } | |
153 | ||
b803b428 MW |
154 | static void xas_advance(struct xa_state *xas) |
155 | { | |
156 | xas->xa_offset++; | |
157 | xas_move_index(xas, xas->xa_offset); | |
158 | } | |
159 | ||
ad3d6c72 MW |
160 | static void *set_bounds(struct xa_state *xas) |
161 | { | |
162 | xas->xa_node = XAS_BOUNDS; | |
163 | return NULL; | |
164 | } | |
165 | ||
166 | /* | |
167 | * Starts a walk. If the @xas is already valid, we assume that it's on | |
168 | * the right path and just return where we've got to. If we're in an | |
169 | * error state, return NULL. If the index is outside the current scope | |
170 | * of the xarray, return NULL without changing @xas->xa_node. Otherwise | |
171 | * set @xas->xa_node to NULL and return the current head of the array. | |
172 | */ | |
173 | static void *xas_start(struct xa_state *xas) | |
174 | { | |
175 | void *entry; | |
176 | ||
177 | if (xas_valid(xas)) | |
178 | return xas_reload(xas); | |
179 | if (xas_error(xas)) | |
180 | return NULL; | |
181 | ||
182 | entry = xa_head(xas->xa); | |
183 | if (!xa_is_node(entry)) { | |
184 | if (xas->xa_index) | |
185 | return set_bounds(xas); | |
186 | } else { | |
187 | if ((xas->xa_index >> xa_to_node(entry)->shift) > XA_CHUNK_MASK) | |
188 | return set_bounds(xas); | |
189 | } | |
190 | ||
191 | xas->xa_node = NULL; | |
192 | return entry; | |
193 | } | |
194 | ||
195 | static void *xas_descend(struct xa_state *xas, struct xa_node *node) | |
196 | { | |
197 | unsigned int offset = get_offset(xas->xa_index, node); | |
198 | void *entry = xa_entry(xas->xa, node, offset); | |
199 | ||
200 | xas->xa_node = node; | |
201 | if (xa_is_sibling(entry)) { | |
202 | offset = xa_to_sibling(entry); | |
203 | entry = xa_entry(xas->xa, node, offset); | |
204 | } | |
205 | ||
206 | xas->xa_offset = offset; | |
207 | return entry; | |
208 | } | |
209 | ||
210 | /** | |
211 | * xas_load() - Load an entry from the XArray (advanced). | |
212 | * @xas: XArray operation state. | |
213 | * | |
214 | * Usually walks the @xas to the appropriate state to load the entry | |
215 | * stored at xa_index. However, it will do nothing and return %NULL if | |
216 | * @xas is in an error state. xas_load() will never expand the tree. | |
217 | * | |
218 | * If the xa_state is set up to operate on a multi-index entry, xas_load() | |
219 | * may return %NULL or an internal entry, even if there are entries | |
220 | * present within the range specified by @xas. | |
221 | * | |
222 | * Context: Any context. The caller should hold the xa_lock or the RCU lock. | |
223 | * Return: Usually an entry in the XArray, but see description for exceptions. | |
224 | */ | |
225 | void *xas_load(struct xa_state *xas) | |
226 | { | |
227 | void *entry = xas_start(xas); | |
228 | ||
229 | while (xa_is_node(entry)) { | |
230 | struct xa_node *node = xa_to_node(entry); | |
231 | ||
232 | if (xas->xa_shift > node->shift) | |
233 | break; | |
234 | entry = xas_descend(xas, node); | |
76b4e529 MW |
235 | if (node->shift == 0) |
236 | break; | |
ad3d6c72 MW |
237 | } |
238 | return entry; | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(xas_load); | |
241 | ||
58d6ea30 MW |
242 | /* Move the radix tree node cache here */ |
243 | extern struct kmem_cache *radix_tree_node_cachep; | |
244 | extern void radix_tree_node_rcu_free(struct rcu_head *head); | |
245 | ||
246 | #define XA_RCU_FREE ((struct xarray *)1) | |
247 | ||
248 | static void xa_node_free(struct xa_node *node) | |
249 | { | |
250 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
251 | node->array = XA_RCU_FREE; | |
252 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); | |
253 | } | |
254 | ||
255 | /* | |
256 | * xas_destroy() - Free any resources allocated during the XArray operation. | |
257 | * @xas: XArray operation state. | |
258 | * | |
259 | * This function is now internal-only. | |
260 | */ | |
261 | static void xas_destroy(struct xa_state *xas) | |
262 | { | |
263 | struct xa_node *node = xas->xa_alloc; | |
264 | ||
265 | if (!node) | |
266 | return; | |
267 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
268 | kmem_cache_free(radix_tree_node_cachep, node); | |
269 | xas->xa_alloc = NULL; | |
270 | } | |
271 | ||
272 | /** | |
273 | * xas_nomem() - Allocate memory if needed. | |
274 | * @xas: XArray operation state. | |
275 | * @gfp: Memory allocation flags. | |
276 | * | |
277 | * If we need to add new nodes to the XArray, we try to allocate memory | |
278 | * with GFP_NOWAIT while holding the lock, which will usually succeed. | |
279 | * If it fails, @xas is flagged as needing memory to continue. The caller | |
280 | * should drop the lock and call xas_nomem(). If xas_nomem() succeeds, | |
281 | * the caller should retry the operation. | |
282 | * | |
283 | * Forward progress is guaranteed as one node is allocated here and | |
284 | * stored in the xa_state where it will be found by xas_alloc(). More | |
285 | * nodes will likely be found in the slab allocator, but we do not tie | |
286 | * them up here. | |
287 | * | |
288 | * Return: true if memory was needed, and was successfully allocated. | |
289 | */ | |
290 | bool xas_nomem(struct xa_state *xas, gfp_t gfp) | |
291 | { | |
292 | if (xas->xa_node != XA_ERROR(-ENOMEM)) { | |
293 | xas_destroy(xas); | |
294 | return false; | |
295 | } | |
296 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
297 | if (!xas->xa_alloc) | |
298 | return false; | |
299 | XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); | |
300 | xas->xa_node = XAS_RESTART; | |
301 | return true; | |
302 | } | |
303 | EXPORT_SYMBOL_GPL(xas_nomem); | |
304 | ||
305 | /* | |
306 | * __xas_nomem() - Drop locks and allocate memory if needed. | |
307 | * @xas: XArray operation state. | |
308 | * @gfp: Memory allocation flags. | |
309 | * | |
310 | * Internal variant of xas_nomem(). | |
311 | * | |
312 | * Return: true if memory was needed, and was successfully allocated. | |
313 | */ | |
314 | static bool __xas_nomem(struct xa_state *xas, gfp_t gfp) | |
315 | __must_hold(xas->xa->xa_lock) | |
316 | { | |
317 | unsigned int lock_type = xa_lock_type(xas->xa); | |
318 | ||
319 | if (xas->xa_node != XA_ERROR(-ENOMEM)) { | |
320 | xas_destroy(xas); | |
321 | return false; | |
322 | } | |
323 | if (gfpflags_allow_blocking(gfp)) { | |
324 | xas_unlock_type(xas, lock_type); | |
325 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
326 | xas_lock_type(xas, lock_type); | |
327 | } else { | |
328 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
329 | } | |
330 | if (!xas->xa_alloc) | |
331 | return false; | |
332 | XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); | |
333 | xas->xa_node = XAS_RESTART; | |
334 | return true; | |
335 | } | |
336 | ||
337 | static void xas_update(struct xa_state *xas, struct xa_node *node) | |
338 | { | |
339 | if (xas->xa_update) | |
340 | xas->xa_update(node); | |
341 | else | |
342 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
343 | } | |
344 | ||
345 | static void *xas_alloc(struct xa_state *xas, unsigned int shift) | |
346 | { | |
347 | struct xa_node *parent = xas->xa_node; | |
348 | struct xa_node *node = xas->xa_alloc; | |
349 | ||
350 | if (xas_invalid(xas)) | |
351 | return NULL; | |
352 | ||
353 | if (node) { | |
354 | xas->xa_alloc = NULL; | |
355 | } else { | |
356 | node = kmem_cache_alloc(radix_tree_node_cachep, | |
357 | GFP_NOWAIT | __GFP_NOWARN); | |
358 | if (!node) { | |
359 | xas_set_err(xas, -ENOMEM); | |
360 | return NULL; | |
361 | } | |
362 | } | |
363 | ||
364 | if (parent) { | |
365 | node->offset = xas->xa_offset; | |
366 | parent->count++; | |
367 | XA_NODE_BUG_ON(node, parent->count > XA_CHUNK_SIZE); | |
368 | xas_update(xas, parent); | |
369 | } | |
370 | XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); | |
371 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
372 | node->shift = shift; | |
373 | node->count = 0; | |
374 | node->nr_values = 0; | |
375 | RCU_INIT_POINTER(node->parent, xas->xa_node); | |
376 | node->array = xas->xa; | |
377 | ||
378 | return node; | |
379 | } | |
380 | ||
0e9446c3 MW |
381 | #ifdef CONFIG_XARRAY_MULTI |
382 | /* Returns the number of indices covered by a given xa_state */ | |
383 | static unsigned long xas_size(const struct xa_state *xas) | |
384 | { | |
385 | return (xas->xa_sibs + 1UL) << xas->xa_shift; | |
386 | } | |
387 | #endif | |
388 | ||
58d6ea30 MW |
389 | /* |
390 | * Use this to calculate the maximum index that will need to be created | |
391 | * in order to add the entry described by @xas. Because we cannot store a | |
392 | * multiple-index entry at index 0, the calculation is a little more complex | |
393 | * than you might expect. | |
394 | */ | |
395 | static unsigned long xas_max(struct xa_state *xas) | |
396 | { | |
397 | unsigned long max = xas->xa_index; | |
398 | ||
399 | #ifdef CONFIG_XARRAY_MULTI | |
400 | if (xas->xa_shift || xas->xa_sibs) { | |
0e9446c3 | 401 | unsigned long mask = xas_size(xas) - 1; |
58d6ea30 MW |
402 | max |= mask; |
403 | if (mask == max) | |
404 | max++; | |
405 | } | |
406 | #endif | |
407 | ||
408 | return max; | |
409 | } | |
410 | ||
411 | /* The maximum index that can be contained in the array without expanding it */ | |
412 | static unsigned long max_index(void *entry) | |
413 | { | |
414 | if (!xa_is_node(entry)) | |
415 | return 0; | |
416 | return (XA_CHUNK_SIZE << xa_to_node(entry)->shift) - 1; | |
417 | } | |
418 | ||
419 | static void xas_shrink(struct xa_state *xas) | |
420 | { | |
421 | struct xarray *xa = xas->xa; | |
422 | struct xa_node *node = xas->xa_node; | |
423 | ||
424 | for (;;) { | |
425 | void *entry; | |
426 | ||
427 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
428 | if (node->count != 1) | |
429 | break; | |
430 | entry = xa_entry_locked(xa, node, 0); | |
431 | if (!entry) | |
432 | break; | |
433 | if (!xa_is_node(entry) && node->shift) | |
434 | break; | |
435 | xas->xa_node = XAS_BOUNDS; | |
436 | ||
437 | RCU_INIT_POINTER(xa->xa_head, entry); | |
371c752d MW |
438 | if (xa_track_free(xa) && !node_get_mark(node, 0, XA_FREE_MARK)) |
439 | xa_mark_clear(xa, XA_FREE_MARK); | |
58d6ea30 MW |
440 | |
441 | node->count = 0; | |
442 | node->nr_values = 0; | |
443 | if (!xa_is_node(entry)) | |
444 | RCU_INIT_POINTER(node->slots[0], XA_RETRY_ENTRY); | |
445 | xas_update(xas, node); | |
446 | xa_node_free(node); | |
447 | if (!xa_is_node(entry)) | |
448 | break; | |
449 | node = xa_to_node(entry); | |
450 | node->parent = NULL; | |
451 | } | |
452 | } | |
453 | ||
454 | /* | |
455 | * xas_delete_node() - Attempt to delete an xa_node | |
456 | * @xas: Array operation state. | |
457 | * | |
458 | * Attempts to delete the @xas->xa_node. This will fail if xa->node has | |
459 | * a non-zero reference count. | |
460 | */ | |
461 | static void xas_delete_node(struct xa_state *xas) | |
462 | { | |
463 | struct xa_node *node = xas->xa_node; | |
464 | ||
465 | for (;;) { | |
466 | struct xa_node *parent; | |
467 | ||
468 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
469 | if (node->count) | |
470 | break; | |
471 | ||
472 | parent = xa_parent_locked(xas->xa, node); | |
473 | xas->xa_node = parent; | |
474 | xas->xa_offset = node->offset; | |
475 | xa_node_free(node); | |
476 | ||
477 | if (!parent) { | |
478 | xas->xa->xa_head = NULL; | |
479 | xas->xa_node = XAS_BOUNDS; | |
480 | return; | |
481 | } | |
482 | ||
483 | parent->slots[xas->xa_offset] = NULL; | |
484 | parent->count--; | |
485 | XA_NODE_BUG_ON(parent, parent->count > XA_CHUNK_SIZE); | |
486 | node = parent; | |
487 | xas_update(xas, node); | |
488 | } | |
489 | ||
490 | if (!node->parent) | |
491 | xas_shrink(xas); | |
492 | } | |
493 | ||
494 | /** | |
495 | * xas_free_nodes() - Free this node and all nodes that it references | |
496 | * @xas: Array operation state. | |
497 | * @top: Node to free | |
498 | * | |
499 | * This node has been removed from the tree. We must now free it and all | |
500 | * of its subnodes. There may be RCU walkers with references into the tree, | |
501 | * so we must replace all entries with retry markers. | |
502 | */ | |
503 | static void xas_free_nodes(struct xa_state *xas, struct xa_node *top) | |
504 | { | |
505 | unsigned int offset = 0; | |
506 | struct xa_node *node = top; | |
507 | ||
508 | for (;;) { | |
509 | void *entry = xa_entry_locked(xas->xa, node, offset); | |
510 | ||
76b4e529 | 511 | if (node->shift && xa_is_node(entry)) { |
58d6ea30 MW |
512 | node = xa_to_node(entry); |
513 | offset = 0; | |
514 | continue; | |
515 | } | |
516 | if (entry) | |
517 | RCU_INIT_POINTER(node->slots[offset], XA_RETRY_ENTRY); | |
518 | offset++; | |
519 | while (offset == XA_CHUNK_SIZE) { | |
520 | struct xa_node *parent; | |
521 | ||
522 | parent = xa_parent_locked(xas->xa, node); | |
523 | offset = node->offset + 1; | |
524 | node->count = 0; | |
525 | node->nr_values = 0; | |
526 | xas_update(xas, node); | |
527 | xa_node_free(node); | |
528 | if (node == top) | |
529 | return; | |
530 | node = parent; | |
531 | } | |
532 | } | |
533 | } | |
534 | ||
535 | /* | |
536 | * xas_expand adds nodes to the head of the tree until it has reached | |
537 | * sufficient height to be able to contain @xas->xa_index | |
538 | */ | |
539 | static int xas_expand(struct xa_state *xas, void *head) | |
540 | { | |
541 | struct xarray *xa = xas->xa; | |
542 | struct xa_node *node = NULL; | |
543 | unsigned int shift = 0; | |
544 | unsigned long max = xas_max(xas); | |
545 | ||
546 | if (!head) { | |
547 | if (max == 0) | |
548 | return 0; | |
549 | while ((max >> shift) >= XA_CHUNK_SIZE) | |
550 | shift += XA_CHUNK_SHIFT; | |
551 | return shift + XA_CHUNK_SHIFT; | |
552 | } else if (xa_is_node(head)) { | |
553 | node = xa_to_node(head); | |
554 | shift = node->shift + XA_CHUNK_SHIFT; | |
555 | } | |
556 | xas->xa_node = NULL; | |
557 | ||
558 | while (max > max_index(head)) { | |
559 | xa_mark_t mark = 0; | |
560 | ||
561 | XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); | |
562 | node = xas_alloc(xas, shift); | |
563 | if (!node) | |
564 | return -ENOMEM; | |
565 | ||
566 | node->count = 1; | |
567 | if (xa_is_value(head)) | |
568 | node->nr_values = 1; | |
569 | RCU_INIT_POINTER(node->slots[0], head); | |
570 | ||
571 | /* Propagate the aggregated mark info to the new child */ | |
572 | for (;;) { | |
371c752d MW |
573 | if (xa_track_free(xa) && mark == XA_FREE_MARK) { |
574 | node_mark_all(node, XA_FREE_MARK); | |
575 | if (!xa_marked(xa, XA_FREE_MARK)) { | |
576 | node_clear_mark(node, 0, XA_FREE_MARK); | |
577 | xa_mark_set(xa, XA_FREE_MARK); | |
578 | } | |
579 | } else if (xa_marked(xa, mark)) { | |
58d6ea30 | 580 | node_set_mark(node, 0, mark); |
371c752d | 581 | } |
58d6ea30 MW |
582 | if (mark == XA_MARK_MAX) |
583 | break; | |
584 | mark_inc(mark); | |
585 | } | |
586 | ||
587 | /* | |
588 | * Now that the new node is fully initialised, we can add | |
589 | * it to the tree | |
590 | */ | |
591 | if (xa_is_node(head)) { | |
592 | xa_to_node(head)->offset = 0; | |
593 | rcu_assign_pointer(xa_to_node(head)->parent, node); | |
594 | } | |
595 | head = xa_mk_node(node); | |
596 | rcu_assign_pointer(xa->xa_head, head); | |
597 | xas_update(xas, node); | |
598 | ||
599 | shift += XA_CHUNK_SHIFT; | |
600 | } | |
601 | ||
602 | xas->xa_node = node; | |
603 | return shift; | |
604 | } | |
605 | ||
606 | /* | |
607 | * xas_create() - Create a slot to store an entry in. | |
608 | * @xas: XArray operation state. | |
76b4e529 | 609 | * @allow_root: %true if we can store the entry in the root directly |
58d6ea30 MW |
610 | * |
611 | * Most users will not need to call this function directly, as it is called | |
612 | * by xas_store(). It is useful for doing conditional store operations | |
613 | * (see the xa_cmpxchg() implementation for an example). | |
614 | * | |
615 | * Return: If the slot already existed, returns the contents of this slot. | |
804dfaf0 MW |
616 | * If the slot was newly created, returns %NULL. If it failed to create the |
617 | * slot, returns %NULL and indicates the error in @xas. | |
58d6ea30 | 618 | */ |
76b4e529 | 619 | static void *xas_create(struct xa_state *xas, bool allow_root) |
58d6ea30 MW |
620 | { |
621 | struct xarray *xa = xas->xa; | |
622 | void *entry; | |
623 | void __rcu **slot; | |
624 | struct xa_node *node = xas->xa_node; | |
625 | int shift; | |
626 | unsigned int order = xas->xa_shift; | |
627 | ||
628 | if (xas_top(node)) { | |
629 | entry = xa_head_locked(xa); | |
630 | xas->xa_node = NULL; | |
631 | shift = xas_expand(xas, entry); | |
632 | if (shift < 0) | |
633 | return NULL; | |
76b4e529 MW |
634 | if (!shift && !allow_root) |
635 | shift = XA_CHUNK_SHIFT; | |
58d6ea30 MW |
636 | entry = xa_head_locked(xa); |
637 | slot = &xa->xa_head; | |
638 | } else if (xas_error(xas)) { | |
639 | return NULL; | |
640 | } else if (node) { | |
641 | unsigned int offset = xas->xa_offset; | |
642 | ||
643 | shift = node->shift; | |
644 | entry = xa_entry_locked(xa, node, offset); | |
645 | slot = &node->slots[offset]; | |
646 | } else { | |
647 | shift = 0; | |
648 | entry = xa_head_locked(xa); | |
649 | slot = &xa->xa_head; | |
650 | } | |
651 | ||
652 | while (shift > order) { | |
653 | shift -= XA_CHUNK_SHIFT; | |
654 | if (!entry) { | |
655 | node = xas_alloc(xas, shift); | |
656 | if (!node) | |
657 | break; | |
371c752d MW |
658 | if (xa_track_free(xa)) |
659 | node_mark_all(node, XA_FREE_MARK); | |
58d6ea30 MW |
660 | rcu_assign_pointer(*slot, xa_mk_node(node)); |
661 | } else if (xa_is_node(entry)) { | |
662 | node = xa_to_node(entry); | |
663 | } else { | |
664 | break; | |
665 | } | |
666 | entry = xas_descend(xas, node); | |
667 | slot = &node->slots[xas->xa_offset]; | |
668 | } | |
669 | ||
670 | return entry; | |
671 | } | |
672 | ||
2264f513 MW |
673 | /** |
674 | * xas_create_range() - Ensure that stores to this range will succeed | |
675 | * @xas: XArray operation state. | |
676 | * | |
677 | * Creates all of the slots in the range covered by @xas. Sets @xas to | |
678 | * create single-index entries and positions it at the beginning of the | |
679 | * range. This is for the benefit of users which have not yet been | |
680 | * converted to use multi-index entries. | |
681 | */ | |
682 | void xas_create_range(struct xa_state *xas) | |
683 | { | |
684 | unsigned long index = xas->xa_index; | |
685 | unsigned char shift = xas->xa_shift; | |
686 | unsigned char sibs = xas->xa_sibs; | |
687 | ||
688 | xas->xa_index |= ((sibs + 1) << shift) - 1; | |
689 | if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift) | |
690 | xas->xa_offset |= sibs; | |
691 | xas->xa_shift = 0; | |
692 | xas->xa_sibs = 0; | |
693 | ||
694 | for (;;) { | |
76b4e529 | 695 | xas_create(xas, true); |
2264f513 MW |
696 | if (xas_error(xas)) |
697 | goto restore; | |
698 | if (xas->xa_index <= (index | XA_CHUNK_MASK)) | |
699 | goto success; | |
700 | xas->xa_index -= XA_CHUNK_SIZE; | |
701 | ||
702 | for (;;) { | |
703 | struct xa_node *node = xas->xa_node; | |
704 | xas->xa_node = xa_parent_locked(xas->xa, node); | |
705 | xas->xa_offset = node->offset - 1; | |
706 | if (node->offset != 0) | |
707 | break; | |
708 | } | |
709 | } | |
710 | ||
711 | restore: | |
712 | xas->xa_shift = shift; | |
713 | xas->xa_sibs = sibs; | |
714 | xas->xa_index = index; | |
715 | return; | |
716 | success: | |
717 | xas->xa_index = index; | |
718 | if (xas->xa_node) | |
719 | xas_set_offset(xas); | |
720 | } | |
721 | EXPORT_SYMBOL_GPL(xas_create_range); | |
722 | ||
58d6ea30 MW |
723 | static void update_node(struct xa_state *xas, struct xa_node *node, |
724 | int count, int values) | |
725 | { | |
726 | if (!node || (!count && !values)) | |
727 | return; | |
728 | ||
729 | node->count += count; | |
730 | node->nr_values += values; | |
731 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
732 | XA_NODE_BUG_ON(node, node->nr_values > XA_CHUNK_SIZE); | |
733 | xas_update(xas, node); | |
734 | if (count < 0) | |
735 | xas_delete_node(xas); | |
736 | } | |
737 | ||
738 | /** | |
739 | * xas_store() - Store this entry in the XArray. | |
740 | * @xas: XArray operation state. | |
741 | * @entry: New entry. | |
742 | * | |
743 | * If @xas is operating on a multi-index entry, the entry returned by this | |
744 | * function is essentially meaningless (it may be an internal entry or it | |
745 | * may be %NULL, even if there are non-NULL entries at some of the indices | |
746 | * covered by the range). This is not a problem for any current users, | |
747 | * and can be changed if needed. | |
748 | * | |
749 | * Return: The old entry at this index. | |
750 | */ | |
751 | void *xas_store(struct xa_state *xas, void *entry) | |
752 | { | |
753 | struct xa_node *node; | |
754 | void __rcu **slot = &xas->xa->xa_head; | |
755 | unsigned int offset, max; | |
756 | int count = 0; | |
757 | int values = 0; | |
758 | void *first, *next; | |
759 | bool value = xa_is_value(entry); | |
760 | ||
761 | if (entry) | |
76b4e529 | 762 | first = xas_create(xas, !xa_is_node(entry)); |
58d6ea30 MW |
763 | else |
764 | first = xas_load(xas); | |
765 | ||
766 | if (xas_invalid(xas)) | |
767 | return first; | |
768 | node = xas->xa_node; | |
769 | if (node && (xas->xa_shift < node->shift)) | |
770 | xas->xa_sibs = 0; | |
771 | if ((first == entry) && !xas->xa_sibs) | |
772 | return first; | |
773 | ||
774 | next = first; | |
775 | offset = xas->xa_offset; | |
776 | max = xas->xa_offset + xas->xa_sibs; | |
777 | if (node) { | |
778 | slot = &node->slots[offset]; | |
779 | if (xas->xa_sibs) | |
780 | xas_squash_marks(xas); | |
781 | } | |
782 | if (!entry) | |
783 | xas_init_marks(xas); | |
784 | ||
785 | for (;;) { | |
786 | /* | |
787 | * Must clear the marks before setting the entry to NULL, | |
788 | * otherwise xas_for_each_marked may find a NULL entry and | |
789 | * stop early. rcu_assign_pointer contains a release barrier | |
790 | * so the mark clearing will appear to happen before the | |
791 | * entry is set to NULL. | |
792 | */ | |
793 | rcu_assign_pointer(*slot, entry); | |
794 | if (xa_is_node(next)) | |
795 | xas_free_nodes(xas, xa_to_node(next)); | |
796 | if (!node) | |
797 | break; | |
798 | count += !next - !entry; | |
799 | values += !xa_is_value(first) - !value; | |
800 | if (entry) { | |
801 | if (offset == max) | |
802 | break; | |
803 | if (!xa_is_sibling(entry)) | |
804 | entry = xa_mk_sibling(xas->xa_offset); | |
805 | } else { | |
806 | if (offset == XA_CHUNK_MASK) | |
807 | break; | |
808 | } | |
809 | next = xa_entry_locked(xas->xa, node, ++offset); | |
810 | if (!xa_is_sibling(next)) { | |
811 | if (!entry && (offset > max)) | |
812 | break; | |
813 | first = next; | |
814 | } | |
815 | slot++; | |
816 | } | |
817 | ||
818 | update_node(xas, node, count, values); | |
819 | return first; | |
820 | } | |
821 | EXPORT_SYMBOL_GPL(xas_store); | |
822 | ||
9b89a035 MW |
823 | /** |
824 | * xas_get_mark() - Returns the state of this mark. | |
825 | * @xas: XArray operation state. | |
826 | * @mark: Mark number. | |
827 | * | |
828 | * Return: true if the mark is set, false if the mark is clear or @xas | |
829 | * is in an error state. | |
830 | */ | |
831 | bool xas_get_mark(const struct xa_state *xas, xa_mark_t mark) | |
832 | { | |
833 | if (xas_invalid(xas)) | |
834 | return false; | |
835 | if (!xas->xa_node) | |
836 | return xa_marked(xas->xa, mark); | |
837 | return node_get_mark(xas->xa_node, xas->xa_offset, mark); | |
838 | } | |
839 | EXPORT_SYMBOL_GPL(xas_get_mark); | |
840 | ||
841 | /** | |
842 | * xas_set_mark() - Sets the mark on this entry and its parents. | |
843 | * @xas: XArray operation state. | |
844 | * @mark: Mark number. | |
845 | * | |
846 | * Sets the specified mark on this entry, and walks up the tree setting it | |
847 | * on all the ancestor entries. Does nothing if @xas has not been walked to | |
848 | * an entry, or is in an error state. | |
849 | */ | |
850 | void xas_set_mark(const struct xa_state *xas, xa_mark_t mark) | |
851 | { | |
852 | struct xa_node *node = xas->xa_node; | |
853 | unsigned int offset = xas->xa_offset; | |
854 | ||
855 | if (xas_invalid(xas)) | |
856 | return; | |
857 | ||
858 | while (node) { | |
859 | if (node_set_mark(node, offset, mark)) | |
860 | return; | |
861 | offset = node->offset; | |
862 | node = xa_parent_locked(xas->xa, node); | |
863 | } | |
864 | ||
865 | if (!xa_marked(xas->xa, mark)) | |
866 | xa_mark_set(xas->xa, mark); | |
867 | } | |
868 | EXPORT_SYMBOL_GPL(xas_set_mark); | |
869 | ||
870 | /** | |
871 | * xas_clear_mark() - Clears the mark on this entry and its parents. | |
872 | * @xas: XArray operation state. | |
873 | * @mark: Mark number. | |
874 | * | |
875 | * Clears the specified mark on this entry, and walks back to the head | |
876 | * attempting to clear it on all the ancestor entries. Does nothing if | |
877 | * @xas has not been walked to an entry, or is in an error state. | |
878 | */ | |
879 | void xas_clear_mark(const struct xa_state *xas, xa_mark_t mark) | |
880 | { | |
881 | struct xa_node *node = xas->xa_node; | |
882 | unsigned int offset = xas->xa_offset; | |
883 | ||
884 | if (xas_invalid(xas)) | |
885 | return; | |
886 | ||
887 | while (node) { | |
888 | if (!node_clear_mark(node, offset, mark)) | |
889 | return; | |
890 | if (node_any_mark(node, mark)) | |
891 | return; | |
892 | ||
893 | offset = node->offset; | |
894 | node = xa_parent_locked(xas->xa, node); | |
895 | } | |
896 | ||
897 | if (xa_marked(xas->xa, mark)) | |
898 | xa_mark_clear(xas->xa, mark); | |
899 | } | |
900 | EXPORT_SYMBOL_GPL(xas_clear_mark); | |
901 | ||
58d6ea30 MW |
902 | /** |
903 | * xas_init_marks() - Initialise all marks for the entry | |
904 | * @xas: Array operations state. | |
905 | * | |
906 | * Initialise all marks for the entry specified by @xas. If we're tracking | |
907 | * free entries with a mark, we need to set it on all entries. All other | |
908 | * marks are cleared. | |
909 | * | |
910 | * This implementation is not as efficient as it could be; we may walk | |
911 | * up the tree multiple times. | |
912 | */ | |
913 | void xas_init_marks(const struct xa_state *xas) | |
914 | { | |
915 | xa_mark_t mark = 0; | |
916 | ||
917 | for (;;) { | |
371c752d MW |
918 | if (xa_track_free(xas->xa) && mark == XA_FREE_MARK) |
919 | xas_set_mark(xas, mark); | |
920 | else | |
921 | xas_clear_mark(xas, mark); | |
58d6ea30 MW |
922 | if (mark == XA_MARK_MAX) |
923 | break; | |
924 | mark_inc(mark); | |
925 | } | |
926 | } | |
927 | EXPORT_SYMBOL_GPL(xas_init_marks); | |
928 | ||
b803b428 MW |
929 | /** |
930 | * xas_pause() - Pause a walk to drop a lock. | |
931 | * @xas: XArray operation state. | |
932 | * | |
933 | * Some users need to pause a walk and drop the lock they're holding in | |
934 | * order to yield to a higher priority thread or carry out an operation | |
935 | * on an entry. Those users should call this function before they drop | |
936 | * the lock. It resets the @xas to be suitable for the next iteration | |
937 | * of the loop after the user has reacquired the lock. If most entries | |
938 | * found during a walk require you to call xas_pause(), the xa_for_each() | |
939 | * iterator may be more appropriate. | |
940 | * | |
941 | * Note that xas_pause() only works for forward iteration. If a user needs | |
942 | * to pause a reverse iteration, we will need a xas_pause_rev(). | |
943 | */ | |
944 | void xas_pause(struct xa_state *xas) | |
945 | { | |
946 | struct xa_node *node = xas->xa_node; | |
947 | ||
948 | if (xas_invalid(xas)) | |
949 | return; | |
950 | ||
951 | if (node) { | |
952 | unsigned int offset = xas->xa_offset; | |
953 | while (++offset < XA_CHUNK_SIZE) { | |
954 | if (!xa_is_sibling(xa_entry(xas->xa, node, offset))) | |
955 | break; | |
956 | } | |
957 | xas->xa_index += (offset - xas->xa_offset) << node->shift; | |
958 | } else { | |
959 | xas->xa_index++; | |
960 | } | |
961 | xas->xa_node = XAS_RESTART; | |
962 | } | |
963 | EXPORT_SYMBOL_GPL(xas_pause); | |
964 | ||
64d3e9a9 MW |
965 | /* |
966 | * __xas_prev() - Find the previous entry in the XArray. | |
967 | * @xas: XArray operation state. | |
968 | * | |
969 | * Helper function for xas_prev() which handles all the complex cases | |
970 | * out of line. | |
971 | */ | |
972 | void *__xas_prev(struct xa_state *xas) | |
973 | { | |
974 | void *entry; | |
975 | ||
976 | if (!xas_frozen(xas->xa_node)) | |
977 | xas->xa_index--; | |
978 | if (xas_not_node(xas->xa_node)) | |
979 | return xas_load(xas); | |
980 | ||
981 | if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) | |
982 | xas->xa_offset--; | |
983 | ||
984 | while (xas->xa_offset == 255) { | |
985 | xas->xa_offset = xas->xa_node->offset - 1; | |
986 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
987 | if (!xas->xa_node) | |
988 | return set_bounds(xas); | |
989 | } | |
990 | ||
991 | for (;;) { | |
992 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
993 | if (!xa_is_node(entry)) | |
994 | return entry; | |
995 | ||
996 | xas->xa_node = xa_to_node(entry); | |
997 | xas_set_offset(xas); | |
998 | } | |
999 | } | |
1000 | EXPORT_SYMBOL_GPL(__xas_prev); | |
1001 | ||
1002 | /* | |
1003 | * __xas_next() - Find the next entry in the XArray. | |
1004 | * @xas: XArray operation state. | |
1005 | * | |
1006 | * Helper function for xas_next() which handles all the complex cases | |
1007 | * out of line. | |
1008 | */ | |
1009 | void *__xas_next(struct xa_state *xas) | |
1010 | { | |
1011 | void *entry; | |
1012 | ||
1013 | if (!xas_frozen(xas->xa_node)) | |
1014 | xas->xa_index++; | |
1015 | if (xas_not_node(xas->xa_node)) | |
1016 | return xas_load(xas); | |
1017 | ||
1018 | if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) | |
1019 | xas->xa_offset++; | |
1020 | ||
1021 | while (xas->xa_offset == XA_CHUNK_SIZE) { | |
1022 | xas->xa_offset = xas->xa_node->offset + 1; | |
1023 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1024 | if (!xas->xa_node) | |
1025 | return set_bounds(xas); | |
1026 | } | |
1027 | ||
1028 | for (;;) { | |
1029 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1030 | if (!xa_is_node(entry)) | |
1031 | return entry; | |
1032 | ||
1033 | xas->xa_node = xa_to_node(entry); | |
1034 | xas_set_offset(xas); | |
1035 | } | |
1036 | } | |
1037 | EXPORT_SYMBOL_GPL(__xas_next); | |
1038 | ||
b803b428 MW |
1039 | /** |
1040 | * xas_find() - Find the next present entry in the XArray. | |
1041 | * @xas: XArray operation state. | |
1042 | * @max: Highest index to return. | |
1043 | * | |
1044 | * If the @xas has not yet been walked to an entry, return the entry | |
1045 | * which has an index >= xas.xa_index. If it has been walked, the entry | |
1046 | * currently being pointed at has been processed, and so we move to the | |
1047 | * next entry. | |
1048 | * | |
1049 | * If no entry is found and the array is smaller than @max, the iterator | |
1050 | * is set to the smallest index not yet in the array. This allows @xas | |
1051 | * to be immediately passed to xas_store(). | |
1052 | * | |
1053 | * Return: The entry, if found, otherwise %NULL. | |
1054 | */ | |
1055 | void *xas_find(struct xa_state *xas, unsigned long max) | |
1056 | { | |
1057 | void *entry; | |
1058 | ||
1059 | if (xas_error(xas)) | |
1060 | return NULL; | |
1061 | ||
1062 | if (!xas->xa_node) { | |
1063 | xas->xa_index = 1; | |
1064 | return set_bounds(xas); | |
1065 | } else if (xas_top(xas->xa_node)) { | |
1066 | entry = xas_load(xas); | |
1067 | if (entry || xas_not_node(xas->xa_node)) | |
1068 | return entry; | |
1069 | } else if (!xas->xa_node->shift && | |
1070 | xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK)) { | |
1071 | xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1; | |
1072 | } | |
1073 | ||
1074 | xas_advance(xas); | |
1075 | ||
1076 | while (xas->xa_node && (xas->xa_index <= max)) { | |
1077 | if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { | |
1078 | xas->xa_offset = xas->xa_node->offset + 1; | |
1079 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1080 | continue; | |
1081 | } | |
1082 | ||
1083 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1084 | if (xa_is_node(entry)) { | |
1085 | xas->xa_node = xa_to_node(entry); | |
1086 | xas->xa_offset = 0; | |
1087 | continue; | |
1088 | } | |
1089 | if (entry && !xa_is_sibling(entry)) | |
1090 | return entry; | |
1091 | ||
1092 | xas_advance(xas); | |
1093 | } | |
1094 | ||
1095 | if (!xas->xa_node) | |
1096 | xas->xa_node = XAS_BOUNDS; | |
1097 | return NULL; | |
1098 | } | |
1099 | EXPORT_SYMBOL_GPL(xas_find); | |
1100 | ||
1101 | /** | |
1102 | * xas_find_marked() - Find the next marked entry in the XArray. | |
1103 | * @xas: XArray operation state. | |
1104 | * @max: Highest index to return. | |
1105 | * @mark: Mark number to search for. | |
1106 | * | |
1107 | * If the @xas has not yet been walked to an entry, return the marked entry | |
1108 | * which has an index >= xas.xa_index. If it has been walked, the entry | |
1109 | * currently being pointed at has been processed, and so we return the | |
1110 | * first marked entry with an index > xas.xa_index. | |
1111 | * | |
1112 | * If no marked entry is found and the array is smaller than @max, @xas is | |
1113 | * set to the bounds state and xas->xa_index is set to the smallest index | |
1114 | * not yet in the array. This allows @xas to be immediately passed to | |
1115 | * xas_store(). | |
1116 | * | |
1117 | * If no entry is found before @max is reached, @xas is set to the restart | |
1118 | * state. | |
1119 | * | |
1120 | * Return: The entry, if found, otherwise %NULL. | |
1121 | */ | |
1122 | void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark) | |
1123 | { | |
1124 | bool advance = true; | |
1125 | unsigned int offset; | |
1126 | void *entry; | |
1127 | ||
1128 | if (xas_error(xas)) | |
1129 | return NULL; | |
1130 | ||
1131 | if (!xas->xa_node) { | |
1132 | xas->xa_index = 1; | |
1133 | goto out; | |
1134 | } else if (xas_top(xas->xa_node)) { | |
1135 | advance = false; | |
1136 | entry = xa_head(xas->xa); | |
1137 | xas->xa_node = NULL; | |
1138 | if (xas->xa_index > max_index(entry)) | |
48483614 | 1139 | goto out; |
b803b428 MW |
1140 | if (!xa_is_node(entry)) { |
1141 | if (xa_marked(xas->xa, mark)) | |
1142 | return entry; | |
1143 | xas->xa_index = 1; | |
1144 | goto out; | |
1145 | } | |
1146 | xas->xa_node = xa_to_node(entry); | |
1147 | xas->xa_offset = xas->xa_index >> xas->xa_node->shift; | |
1148 | } | |
1149 | ||
1150 | while (xas->xa_index <= max) { | |
1151 | if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { | |
1152 | xas->xa_offset = xas->xa_node->offset + 1; | |
1153 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1154 | if (!xas->xa_node) | |
1155 | break; | |
1156 | advance = false; | |
1157 | continue; | |
1158 | } | |
1159 | ||
1160 | if (!advance) { | |
1161 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1162 | if (xa_is_sibling(entry)) { | |
1163 | xas->xa_offset = xa_to_sibling(entry); | |
1164 | xas_move_index(xas, xas->xa_offset); | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | offset = xas_find_chunk(xas, advance, mark); | |
1169 | if (offset > xas->xa_offset) { | |
1170 | advance = false; | |
1171 | xas_move_index(xas, offset); | |
1172 | /* Mind the wrap */ | |
1173 | if ((xas->xa_index - 1) >= max) | |
1174 | goto max; | |
1175 | xas->xa_offset = offset; | |
1176 | if (offset == XA_CHUNK_SIZE) | |
1177 | continue; | |
1178 | } | |
1179 | ||
1180 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1181 | if (!xa_is_node(entry)) | |
1182 | return entry; | |
1183 | xas->xa_node = xa_to_node(entry); | |
1184 | xas_set_offset(xas); | |
1185 | } | |
1186 | ||
1187 | out: | |
48483614 | 1188 | if (xas->xa_index > max) |
b803b428 | 1189 | goto max; |
48483614 | 1190 | return set_bounds(xas); |
b803b428 MW |
1191 | max: |
1192 | xas->xa_node = XAS_RESTART; | |
1193 | return NULL; | |
1194 | } | |
1195 | EXPORT_SYMBOL_GPL(xas_find_marked); | |
1196 | ||
4e99d4e9 MW |
1197 | /** |
1198 | * xas_find_conflict() - Find the next present entry in a range. | |
1199 | * @xas: XArray operation state. | |
1200 | * | |
1201 | * The @xas describes both a range and a position within that range. | |
1202 | * | |
1203 | * Context: Any context. Expects xa_lock to be held. | |
1204 | * Return: The next entry in the range covered by @xas or %NULL. | |
1205 | */ | |
1206 | void *xas_find_conflict(struct xa_state *xas) | |
1207 | { | |
1208 | void *curr; | |
1209 | ||
1210 | if (xas_error(xas)) | |
1211 | return NULL; | |
1212 | ||
1213 | if (!xas->xa_node) | |
1214 | return NULL; | |
1215 | ||
1216 | if (xas_top(xas->xa_node)) { | |
1217 | curr = xas_start(xas); | |
1218 | if (!curr) | |
1219 | return NULL; | |
1220 | while (xa_is_node(curr)) { | |
1221 | struct xa_node *node = xa_to_node(curr); | |
1222 | curr = xas_descend(xas, node); | |
1223 | } | |
1224 | if (curr) | |
1225 | return curr; | |
1226 | } | |
1227 | ||
1228 | if (xas->xa_node->shift > xas->xa_shift) | |
1229 | return NULL; | |
1230 | ||
1231 | for (;;) { | |
1232 | if (xas->xa_node->shift == xas->xa_shift) { | |
1233 | if ((xas->xa_offset & xas->xa_sibs) == xas->xa_sibs) | |
1234 | break; | |
1235 | } else if (xas->xa_offset == XA_CHUNK_MASK) { | |
1236 | xas->xa_offset = xas->xa_node->offset; | |
1237 | xas->xa_node = xa_parent_locked(xas->xa, xas->xa_node); | |
1238 | if (!xas->xa_node) | |
1239 | break; | |
1240 | continue; | |
1241 | } | |
1242 | curr = xa_entry_locked(xas->xa, xas->xa_node, ++xas->xa_offset); | |
1243 | if (xa_is_sibling(curr)) | |
1244 | continue; | |
1245 | while (xa_is_node(curr)) { | |
1246 | xas->xa_node = xa_to_node(curr); | |
1247 | xas->xa_offset = 0; | |
1248 | curr = xa_entry_locked(xas->xa, xas->xa_node, 0); | |
1249 | } | |
1250 | if (curr) | |
1251 | return curr; | |
1252 | } | |
1253 | xas->xa_offset -= xas->xa_sibs; | |
1254 | return NULL; | |
1255 | } | |
1256 | EXPORT_SYMBOL_GPL(xas_find_conflict); | |
1257 | ||
ad3d6c72 MW |
1258 | /** |
1259 | * xa_load() - Load an entry from an XArray. | |
1260 | * @xa: XArray. | |
1261 | * @index: index into array. | |
1262 | * | |
1263 | * Context: Any context. Takes and releases the RCU lock. | |
1264 | * Return: The entry at @index in @xa. | |
1265 | */ | |
1266 | void *xa_load(struct xarray *xa, unsigned long index) | |
1267 | { | |
1268 | XA_STATE(xas, xa, index); | |
1269 | void *entry; | |
1270 | ||
1271 | rcu_read_lock(); | |
1272 | do { | |
1273 | entry = xas_load(&xas); | |
9f14d4f1 MW |
1274 | if (xa_is_zero(entry)) |
1275 | entry = NULL; | |
ad3d6c72 MW |
1276 | } while (xas_retry(&xas, entry)); |
1277 | rcu_read_unlock(); | |
1278 | ||
1279 | return entry; | |
1280 | } | |
1281 | EXPORT_SYMBOL(xa_load); | |
1282 | ||
58d6ea30 MW |
1283 | static void *xas_result(struct xa_state *xas, void *curr) |
1284 | { | |
9f14d4f1 MW |
1285 | if (xa_is_zero(curr)) |
1286 | return NULL; | |
58d6ea30 MW |
1287 | if (xas_error(xas)) |
1288 | curr = xas->xa_node; | |
1289 | return curr; | |
1290 | } | |
1291 | ||
1292 | /** | |
1293 | * __xa_erase() - Erase this entry from the XArray while locked. | |
1294 | * @xa: XArray. | |
1295 | * @index: Index into array. | |
1296 | * | |
809ab937 MW |
1297 | * After this function returns, loading from @index will return %NULL. |
1298 | * If the index is part of a multi-index entry, all indices will be erased | |
1299 | * and none of the entries will be part of a multi-index entry. | |
58d6ea30 | 1300 | * |
809ab937 MW |
1301 | * Context: Any context. Expects xa_lock to be held on entry. |
1302 | * Return: The entry which used to be at this index. | |
58d6ea30 MW |
1303 | */ |
1304 | void *__xa_erase(struct xarray *xa, unsigned long index) | |
1305 | { | |
1306 | XA_STATE(xas, xa, index); | |
1307 | return xas_result(&xas, xas_store(&xas, NULL)); | |
1308 | } | |
9ee5a3b7 | 1309 | EXPORT_SYMBOL(__xa_erase); |
58d6ea30 | 1310 | |
9c16bb88 MW |
1311 | /** |
1312 | * xa_erase() - Erase this entry from the XArray. | |
1313 | * @xa: XArray. | |
1314 | * @index: Index of entry. | |
1315 | * | |
809ab937 MW |
1316 | * After this function returns, loading from @index will return %NULL. |
1317 | * If the index is part of a multi-index entry, all indices will be erased | |
1318 | * and none of the entries will be part of a multi-index entry. | |
9c16bb88 MW |
1319 | * |
1320 | * Context: Any context. Takes and releases the xa_lock. | |
1321 | * Return: The entry which used to be at this index. | |
1322 | */ | |
1323 | void *xa_erase(struct xarray *xa, unsigned long index) | |
1324 | { | |
1325 | void *entry; | |
1326 | ||
1327 | xa_lock(xa); | |
1328 | entry = __xa_erase(xa, index); | |
1329 | xa_unlock(xa); | |
1330 | ||
1331 | return entry; | |
1332 | } | |
1333 | EXPORT_SYMBOL(xa_erase); | |
1334 | ||
58d6ea30 | 1335 | /** |
611f3186 | 1336 | * __xa_store() - Store this entry in the XArray. |
58d6ea30 MW |
1337 | * @xa: XArray. |
1338 | * @index: Index into array. | |
1339 | * @entry: New entry. | |
1340 | * @gfp: Memory allocation flags. | |
1341 | * | |
611f3186 MW |
1342 | * You must already be holding the xa_lock when calling this function. |
1343 | * It will drop the lock if needed to allocate memory, and then reacquire | |
1344 | * it afterwards. | |
58d6ea30 | 1345 | * |
611f3186 MW |
1346 | * Context: Any context. Expects xa_lock to be held on entry. May |
1347 | * release and reacquire xa_lock if @gfp flags permit. | |
1348 | * Return: The old entry at this index or xa_err() if an error happened. | |
58d6ea30 | 1349 | */ |
611f3186 | 1350 | void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) |
58d6ea30 MW |
1351 | { |
1352 | XA_STATE(xas, xa, index); | |
1353 | void *curr; | |
1354 | ||
76b4e529 | 1355 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
58d6ea30 | 1356 | return XA_ERROR(-EINVAL); |
d9c48043 MW |
1357 | if (xa_track_free(xa) && !entry) |
1358 | entry = XA_ZERO_ENTRY; | |
58d6ea30 MW |
1359 | |
1360 | do { | |
58d6ea30 | 1361 | curr = xas_store(&xas, entry); |
d9c48043 | 1362 | if (xa_track_free(xa)) |
371c752d | 1363 | xas_clear_mark(&xas, XA_FREE_MARK); |
611f3186 | 1364 | } while (__xas_nomem(&xas, gfp)); |
58d6ea30 MW |
1365 | |
1366 | return xas_result(&xas, curr); | |
1367 | } | |
611f3186 | 1368 | EXPORT_SYMBOL(__xa_store); |
58d6ea30 MW |
1369 | |
1370 | /** | |
611f3186 | 1371 | * xa_store() - Store this entry in the XArray. |
58d6ea30 MW |
1372 | * @xa: XArray. |
1373 | * @index: Index into array. | |
1374 | * @entry: New entry. | |
1375 | * @gfp: Memory allocation flags. | |
1376 | * | |
611f3186 MW |
1377 | * After this function returns, loads from this index will return @entry. |
1378 | * Storing into an existing multislot entry updates the entry of every index. | |
1379 | * The marks associated with @index are unaffected unless @entry is %NULL. | |
58d6ea30 | 1380 | * |
611f3186 MW |
1381 | * Context: Any context. Takes and releases the xa_lock. |
1382 | * May sleep if the @gfp flags permit. | |
1383 | * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry | |
1384 | * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation | |
1385 | * failed. | |
58d6ea30 | 1386 | */ |
611f3186 | 1387 | void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) |
58d6ea30 | 1388 | { |
58d6ea30 MW |
1389 | void *curr; |
1390 | ||
611f3186 MW |
1391 | xa_lock(xa); |
1392 | curr = __xa_store(xa, index, entry, gfp); | |
1393 | xa_unlock(xa); | |
58d6ea30 | 1394 | |
611f3186 | 1395 | return curr; |
58d6ea30 | 1396 | } |
611f3186 | 1397 | EXPORT_SYMBOL(xa_store); |
58d6ea30 | 1398 | |
41aec91f MW |
1399 | /** |
1400 | * __xa_cmpxchg() - Store this entry in the XArray. | |
1401 | * @xa: XArray. | |
1402 | * @index: Index into array. | |
1403 | * @old: Old value to test against. | |
1404 | * @entry: New entry. | |
1405 | * @gfp: Memory allocation flags. | |
1406 | * | |
1407 | * You must already be holding the xa_lock when calling this function. | |
1408 | * It will drop the lock if needed to allocate memory, and then reacquire | |
1409 | * it afterwards. | |
1410 | * | |
1411 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1412 | * release and reacquire xa_lock if @gfp flags permit. | |
1413 | * Return: The old entry at this index or xa_err() if an error happened. | |
1414 | */ | |
1415 | void *__xa_cmpxchg(struct xarray *xa, unsigned long index, | |
1416 | void *old, void *entry, gfp_t gfp) | |
1417 | { | |
1418 | XA_STATE(xas, xa, index); | |
1419 | void *curr; | |
1420 | ||
76b4e529 | 1421 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
41aec91f | 1422 | return XA_ERROR(-EINVAL); |
d9c48043 MW |
1423 | if (xa_track_free(xa) && !entry) |
1424 | entry = XA_ZERO_ENTRY; | |
41aec91f MW |
1425 | |
1426 | do { | |
1427 | curr = xas_load(&xas); | |
9f14d4f1 MW |
1428 | if (curr == XA_ZERO_ENTRY) |
1429 | curr = NULL; | |
371c752d | 1430 | if (curr == old) { |
41aec91f | 1431 | xas_store(&xas, entry); |
d9c48043 | 1432 | if (xa_track_free(xa)) |
371c752d MW |
1433 | xas_clear_mark(&xas, XA_FREE_MARK); |
1434 | } | |
41aec91f MW |
1435 | } while (__xas_nomem(&xas, gfp)); |
1436 | ||
1437 | return xas_result(&xas, curr); | |
1438 | } | |
1439 | EXPORT_SYMBOL(__xa_cmpxchg); | |
1440 | ||
b0606fed MW |
1441 | /** |
1442 | * __xa_insert() - Store this entry in the XArray if no entry is present. | |
1443 | * @xa: XArray. | |
1444 | * @index: Index into array. | |
1445 | * @entry: New entry. | |
1446 | * @gfp: Memory allocation flags. | |
1447 | * | |
1448 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) | |
1449 | * if no entry is present. Inserting will fail if a reserved entry is | |
1450 | * present, even though loading from this index will return NULL. | |
1451 | * | |
1452 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1453 | * release and reacquire xa_lock if @gfp flags permit. | |
1454 | * Return: 0 if the store succeeded. -EEXIST if another entry was present. | |
1455 | * -ENOMEM if memory could not be allocated. | |
1456 | */ | |
1457 | int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) | |
1458 | { | |
1459 | XA_STATE(xas, xa, index); | |
1460 | void *curr; | |
1461 | ||
1462 | if (WARN_ON_ONCE(xa_is_advanced(entry))) | |
1463 | return -EINVAL; | |
1464 | if (!entry) | |
1465 | entry = XA_ZERO_ENTRY; | |
1466 | ||
1467 | do { | |
1468 | curr = xas_load(&xas); | |
1469 | if (!curr) { | |
1470 | xas_store(&xas, entry); | |
1471 | if (xa_track_free(xa)) | |
1472 | xas_clear_mark(&xas, XA_FREE_MARK); | |
1473 | } else { | |
1474 | xas_set_err(&xas, -EEXIST); | |
1475 | } | |
1476 | } while (__xas_nomem(&xas, gfp)); | |
1477 | ||
1478 | return xas_error(&xas); | |
1479 | } | |
1480 | EXPORT_SYMBOL(__xa_insert); | |
1481 | ||
9f14d4f1 | 1482 | /** |
4c0608f4 | 1483 | * __xa_reserve() - Reserve this index in the XArray. |
9f14d4f1 MW |
1484 | * @xa: XArray. |
1485 | * @index: Index into array. | |
1486 | * @gfp: Memory allocation flags. | |
1487 | * | |
1488 | * Ensures there is somewhere to store an entry at @index in the array. | |
1489 | * If there is already something stored at @index, this function does | |
1490 | * nothing. If there was nothing there, the entry is marked as reserved. | |
4c0608f4 | 1491 | * Loading from a reserved entry returns a %NULL pointer. |
9f14d4f1 MW |
1492 | * |
1493 | * If you do not use the entry that you have reserved, call xa_release() | |
1494 | * or xa_erase() to free any unnecessary memory. | |
1495 | * | |
4c0608f4 MW |
1496 | * Context: Any context. Expects the xa_lock to be held on entry. May |
1497 | * release the lock, sleep and reacquire the lock if the @gfp flags permit. | |
9f14d4f1 MW |
1498 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
1499 | */ | |
4c0608f4 | 1500 | int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) |
9f14d4f1 MW |
1501 | { |
1502 | XA_STATE(xas, xa, index); | |
9f14d4f1 MW |
1503 | void *curr; |
1504 | ||
1505 | do { | |
9f14d4f1 | 1506 | curr = xas_load(&xas); |
d9c48043 | 1507 | if (!curr) { |
9f14d4f1 | 1508 | xas_store(&xas, XA_ZERO_ENTRY); |
d9c48043 MW |
1509 | if (xa_track_free(xa)) |
1510 | xas_clear_mark(&xas, XA_FREE_MARK); | |
1511 | } | |
4c0608f4 | 1512 | } while (__xas_nomem(&xas, gfp)); |
9f14d4f1 MW |
1513 | |
1514 | return xas_error(&xas); | |
1515 | } | |
4c0608f4 | 1516 | EXPORT_SYMBOL(__xa_reserve); |
9f14d4f1 | 1517 | |
0e9446c3 MW |
1518 | #ifdef CONFIG_XARRAY_MULTI |
1519 | static void xas_set_range(struct xa_state *xas, unsigned long first, | |
1520 | unsigned long last) | |
1521 | { | |
1522 | unsigned int shift = 0; | |
1523 | unsigned long sibs = last - first; | |
1524 | unsigned int offset = XA_CHUNK_MASK; | |
1525 | ||
1526 | xas_set(xas, first); | |
1527 | ||
1528 | while ((first & XA_CHUNK_MASK) == 0) { | |
1529 | if (sibs < XA_CHUNK_MASK) | |
1530 | break; | |
1531 | if ((sibs == XA_CHUNK_MASK) && (offset < XA_CHUNK_MASK)) | |
1532 | break; | |
1533 | shift += XA_CHUNK_SHIFT; | |
1534 | if (offset == XA_CHUNK_MASK) | |
1535 | offset = sibs & XA_CHUNK_MASK; | |
1536 | sibs >>= XA_CHUNK_SHIFT; | |
1537 | first >>= XA_CHUNK_SHIFT; | |
1538 | } | |
1539 | ||
1540 | offset = first & XA_CHUNK_MASK; | |
1541 | if (offset + sibs > XA_CHUNK_MASK) | |
1542 | sibs = XA_CHUNK_MASK - offset; | |
1543 | if ((((first + sibs + 1) << shift) - 1) > last) | |
1544 | sibs -= 1; | |
1545 | ||
1546 | xas->xa_shift = shift; | |
1547 | xas->xa_sibs = sibs; | |
1548 | } | |
1549 | ||
1550 | /** | |
1551 | * xa_store_range() - Store this entry at a range of indices in the XArray. | |
1552 | * @xa: XArray. | |
1553 | * @first: First index to affect. | |
1554 | * @last: Last index to affect. | |
1555 | * @entry: New entry. | |
1556 | * @gfp: Memory allocation flags. | |
1557 | * | |
1558 | * After this function returns, loads from any index between @first and @last, | |
1559 | * inclusive will return @entry. | |
1560 | * Storing into an existing multislot entry updates the entry of every index. | |
1561 | * The marks associated with @index are unaffected unless @entry is %NULL. | |
1562 | * | |
1563 | * Context: Process context. Takes and releases the xa_lock. May sleep | |
1564 | * if the @gfp flags permit. | |
1565 | * Return: %NULL on success, xa_err(-EINVAL) if @entry cannot be stored in | |
1566 | * an XArray, or xa_err(-ENOMEM) if memory allocation failed. | |
1567 | */ | |
1568 | void *xa_store_range(struct xarray *xa, unsigned long first, | |
1569 | unsigned long last, void *entry, gfp_t gfp) | |
1570 | { | |
1571 | XA_STATE(xas, xa, 0); | |
1572 | ||
1573 | if (WARN_ON_ONCE(xa_is_internal(entry))) | |
1574 | return XA_ERROR(-EINVAL); | |
1575 | if (last < first) | |
1576 | return XA_ERROR(-EINVAL); | |
1577 | ||
1578 | do { | |
1579 | xas_lock(&xas); | |
1580 | if (entry) { | |
44a4a66b MW |
1581 | unsigned int order = BITS_PER_LONG; |
1582 | if (last + 1) | |
1583 | order = __ffs(last + 1); | |
0e9446c3 | 1584 | xas_set_order(&xas, last, order); |
76b4e529 | 1585 | xas_create(&xas, true); |
0e9446c3 MW |
1586 | if (xas_error(&xas)) |
1587 | goto unlock; | |
1588 | } | |
1589 | do { | |
1590 | xas_set_range(&xas, first, last); | |
1591 | xas_store(&xas, entry); | |
1592 | if (xas_error(&xas)) | |
1593 | goto unlock; | |
1594 | first += xas_size(&xas); | |
1595 | } while (first <= last); | |
1596 | unlock: | |
1597 | xas_unlock(&xas); | |
1598 | } while (xas_nomem(&xas, gfp)); | |
1599 | ||
1600 | return xas_result(&xas, NULL); | |
1601 | } | |
1602 | EXPORT_SYMBOL(xa_store_range); | |
1603 | #endif /* CONFIG_XARRAY_MULTI */ | |
1604 | ||
371c752d MW |
1605 | /** |
1606 | * __xa_alloc() - Find somewhere to store this entry in the XArray. | |
1607 | * @xa: XArray. | |
1608 | * @id: Pointer to ID. | |
1609 | * @max: Maximum ID to allocate (inclusive). | |
1610 | * @entry: New entry. | |
1611 | * @gfp: Memory allocation flags. | |
1612 | * | |
1613 | * Allocates an unused ID in the range specified by @id and @max. | |
1614 | * Updates the @id pointer with the index, then stores the entry at that | |
1615 | * index. A concurrent lookup will not see an uninitialised @id. | |
1616 | * | |
1617 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1618 | * release and reacquire xa_lock if @gfp flags permit. | |
1619 | * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if | |
1620 | * there is no more space in the XArray. | |
1621 | */ | |
1622 | int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) | |
1623 | { | |
1624 | XA_STATE(xas, xa, 0); | |
1625 | int err; | |
1626 | ||
76b4e529 | 1627 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
371c752d MW |
1628 | return -EINVAL; |
1629 | if (WARN_ON_ONCE(!xa_track_free(xa))) | |
1630 | return -EINVAL; | |
1631 | ||
1632 | if (!entry) | |
1633 | entry = XA_ZERO_ENTRY; | |
1634 | ||
1635 | do { | |
1636 | xas.xa_index = *id; | |
1637 | xas_find_marked(&xas, max, XA_FREE_MARK); | |
1638 | if (xas.xa_node == XAS_RESTART) | |
1639 | xas_set_err(&xas, -ENOSPC); | |
1640 | xas_store(&xas, entry); | |
1641 | xas_clear_mark(&xas, XA_FREE_MARK); | |
1642 | } while (__xas_nomem(&xas, gfp)); | |
1643 | ||
1644 | err = xas_error(&xas); | |
1645 | if (!err) | |
1646 | *id = xas.xa_index; | |
1647 | return err; | |
1648 | } | |
1649 | EXPORT_SYMBOL(__xa_alloc); | |
1650 | ||
9b89a035 MW |
1651 | /** |
1652 | * __xa_set_mark() - Set this mark on this entry while locked. | |
1653 | * @xa: XArray. | |
1654 | * @index: Index of entry. | |
1655 | * @mark: Mark number. | |
1656 | * | |
804dfaf0 | 1657 | * Attempting to set a mark on a %NULL entry does not succeed. |
9b89a035 MW |
1658 | * |
1659 | * Context: Any context. Expects xa_lock to be held on entry. | |
1660 | */ | |
1661 | void __xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1662 | { | |
1663 | XA_STATE(xas, xa, index); | |
1664 | void *entry = xas_load(&xas); | |
1665 | ||
1666 | if (entry) | |
1667 | xas_set_mark(&xas, mark); | |
1668 | } | |
9ee5a3b7 | 1669 | EXPORT_SYMBOL(__xa_set_mark); |
9b89a035 MW |
1670 | |
1671 | /** | |
1672 | * __xa_clear_mark() - Clear this mark on this entry while locked. | |
1673 | * @xa: XArray. | |
1674 | * @index: Index of entry. | |
1675 | * @mark: Mark number. | |
1676 | * | |
1677 | * Context: Any context. Expects xa_lock to be held on entry. | |
1678 | */ | |
1679 | void __xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1680 | { | |
1681 | XA_STATE(xas, xa, index); | |
1682 | void *entry = xas_load(&xas); | |
1683 | ||
1684 | if (entry) | |
1685 | xas_clear_mark(&xas, mark); | |
1686 | } | |
9ee5a3b7 | 1687 | EXPORT_SYMBOL(__xa_clear_mark); |
9b89a035 MW |
1688 | |
1689 | /** | |
1690 | * xa_get_mark() - Inquire whether this mark is set on this entry. | |
1691 | * @xa: XArray. | |
1692 | * @index: Index of entry. | |
1693 | * @mark: Mark number. | |
1694 | * | |
1695 | * This function uses the RCU read lock, so the result may be out of date | |
1696 | * by the time it returns. If you need the result to be stable, use a lock. | |
1697 | * | |
1698 | * Context: Any context. Takes and releases the RCU lock. | |
1699 | * Return: True if the entry at @index has this mark set, false if it doesn't. | |
1700 | */ | |
1701 | bool xa_get_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1702 | { | |
1703 | XA_STATE(xas, xa, index); | |
1704 | void *entry; | |
1705 | ||
1706 | rcu_read_lock(); | |
1707 | entry = xas_start(&xas); | |
1708 | while (xas_get_mark(&xas, mark)) { | |
1709 | if (!xa_is_node(entry)) | |
1710 | goto found; | |
1711 | entry = xas_descend(&xas, xa_to_node(entry)); | |
1712 | } | |
1713 | rcu_read_unlock(); | |
1714 | return false; | |
1715 | found: | |
1716 | rcu_read_unlock(); | |
1717 | return true; | |
1718 | } | |
1719 | EXPORT_SYMBOL(xa_get_mark); | |
1720 | ||
1721 | /** | |
1722 | * xa_set_mark() - Set this mark on this entry. | |
1723 | * @xa: XArray. | |
1724 | * @index: Index of entry. | |
1725 | * @mark: Mark number. | |
1726 | * | |
804dfaf0 | 1727 | * Attempting to set a mark on a %NULL entry does not succeed. |
9b89a035 MW |
1728 | * |
1729 | * Context: Process context. Takes and releases the xa_lock. | |
1730 | */ | |
1731 | void xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1732 | { | |
1733 | xa_lock(xa); | |
1734 | __xa_set_mark(xa, index, mark); | |
1735 | xa_unlock(xa); | |
1736 | } | |
1737 | EXPORT_SYMBOL(xa_set_mark); | |
1738 | ||
1739 | /** | |
1740 | * xa_clear_mark() - Clear this mark on this entry. | |
1741 | * @xa: XArray. | |
1742 | * @index: Index of entry. | |
1743 | * @mark: Mark number. | |
1744 | * | |
1745 | * Clearing a mark always succeeds. | |
1746 | * | |
1747 | * Context: Process context. Takes and releases the xa_lock. | |
1748 | */ | |
1749 | void xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1750 | { | |
1751 | xa_lock(xa); | |
1752 | __xa_clear_mark(xa, index, mark); | |
1753 | xa_unlock(xa); | |
1754 | } | |
1755 | EXPORT_SYMBOL(xa_clear_mark); | |
1756 | ||
b803b428 MW |
1757 | /** |
1758 | * xa_find() - Search the XArray for an entry. | |
1759 | * @xa: XArray. | |
1760 | * @indexp: Pointer to an index. | |
1761 | * @max: Maximum index to search to. | |
1762 | * @filter: Selection criterion. | |
1763 | * | |
1764 | * Finds the entry in @xa which matches the @filter, and has the lowest | |
1765 | * index that is at least @indexp and no more than @max. | |
1766 | * If an entry is found, @indexp is updated to be the index of the entry. | |
1767 | * This function is protected by the RCU read lock, so it may not find | |
1768 | * entries which are being simultaneously added. It will not return an | |
1769 | * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). | |
1770 | * | |
1771 | * Context: Any context. Takes and releases the RCU lock. | |
1772 | * Return: The entry, if found, otherwise %NULL. | |
1773 | */ | |
1774 | void *xa_find(struct xarray *xa, unsigned long *indexp, | |
1775 | unsigned long max, xa_mark_t filter) | |
1776 | { | |
1777 | XA_STATE(xas, xa, *indexp); | |
1778 | void *entry; | |
1779 | ||
1780 | rcu_read_lock(); | |
1781 | do { | |
1782 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
1783 | entry = xas_find_marked(&xas, max, filter); | |
1784 | else | |
1785 | entry = xas_find(&xas, max); | |
1786 | } while (xas_retry(&xas, entry)); | |
1787 | rcu_read_unlock(); | |
1788 | ||
1789 | if (entry) | |
1790 | *indexp = xas.xa_index; | |
1791 | return entry; | |
1792 | } | |
1793 | EXPORT_SYMBOL(xa_find); | |
1794 | ||
1795 | /** | |
1796 | * xa_find_after() - Search the XArray for a present entry. | |
1797 | * @xa: XArray. | |
1798 | * @indexp: Pointer to an index. | |
1799 | * @max: Maximum index to search to. | |
1800 | * @filter: Selection criterion. | |
1801 | * | |
1802 | * Finds the entry in @xa which matches the @filter and has the lowest | |
1803 | * index that is above @indexp and no more than @max. | |
1804 | * If an entry is found, @indexp is updated to be the index of the entry. | |
1805 | * This function is protected by the RCU read lock, so it may miss entries | |
1806 | * which are being simultaneously added. It will not return an | |
1807 | * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). | |
1808 | * | |
1809 | * Context: Any context. Takes and releases the RCU lock. | |
1810 | * Return: The pointer, if found, otherwise %NULL. | |
1811 | */ | |
1812 | void *xa_find_after(struct xarray *xa, unsigned long *indexp, | |
1813 | unsigned long max, xa_mark_t filter) | |
1814 | { | |
1815 | XA_STATE(xas, xa, *indexp + 1); | |
1816 | void *entry; | |
1817 | ||
1818 | rcu_read_lock(); | |
1819 | for (;;) { | |
1820 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
1821 | entry = xas_find_marked(&xas, max, filter); | |
1822 | else | |
1823 | entry = xas_find(&xas, max); | |
8229706e MW |
1824 | if (xas.xa_node == XAS_BOUNDS) |
1825 | break; | |
b803b428 MW |
1826 | if (xas.xa_shift) { |
1827 | if (xas.xa_index & ((1UL << xas.xa_shift) - 1)) | |
1828 | continue; | |
1829 | } else { | |
1830 | if (xas.xa_offset < (xas.xa_index & XA_CHUNK_MASK)) | |
1831 | continue; | |
1832 | } | |
1833 | if (!xas_retry(&xas, entry)) | |
1834 | break; | |
1835 | } | |
1836 | rcu_read_unlock(); | |
1837 | ||
1838 | if (entry) | |
1839 | *indexp = xas.xa_index; | |
1840 | return entry; | |
1841 | } | |
1842 | EXPORT_SYMBOL(xa_find_after); | |
1843 | ||
80a0a1a9 MW |
1844 | static unsigned int xas_extract_present(struct xa_state *xas, void **dst, |
1845 | unsigned long max, unsigned int n) | |
1846 | { | |
1847 | void *entry; | |
1848 | unsigned int i = 0; | |
1849 | ||
1850 | rcu_read_lock(); | |
1851 | xas_for_each(xas, entry, max) { | |
1852 | if (xas_retry(xas, entry)) | |
1853 | continue; | |
1854 | dst[i++] = entry; | |
1855 | if (i == n) | |
1856 | break; | |
1857 | } | |
1858 | rcu_read_unlock(); | |
1859 | ||
1860 | return i; | |
1861 | } | |
1862 | ||
1863 | static unsigned int xas_extract_marked(struct xa_state *xas, void **dst, | |
1864 | unsigned long max, unsigned int n, xa_mark_t mark) | |
1865 | { | |
1866 | void *entry; | |
1867 | unsigned int i = 0; | |
1868 | ||
1869 | rcu_read_lock(); | |
1870 | xas_for_each_marked(xas, entry, max, mark) { | |
1871 | if (xas_retry(xas, entry)) | |
1872 | continue; | |
1873 | dst[i++] = entry; | |
1874 | if (i == n) | |
1875 | break; | |
1876 | } | |
1877 | rcu_read_unlock(); | |
1878 | ||
1879 | return i; | |
1880 | } | |
1881 | ||
1882 | /** | |
1883 | * xa_extract() - Copy selected entries from the XArray into a normal array. | |
1884 | * @xa: The source XArray to copy from. | |
1885 | * @dst: The buffer to copy entries into. | |
1886 | * @start: The first index in the XArray eligible to be selected. | |
1887 | * @max: The last index in the XArray eligible to be selected. | |
1888 | * @n: The maximum number of entries to copy. | |
1889 | * @filter: Selection criterion. | |
1890 | * | |
1891 | * Copies up to @n entries that match @filter from the XArray. The | |
1892 | * copied entries will have indices between @start and @max, inclusive. | |
1893 | * | |
1894 | * The @filter may be an XArray mark value, in which case entries which are | |
1895 | * marked with that mark will be copied. It may also be %XA_PRESENT, in | |
804dfaf0 | 1896 | * which case all entries which are not %NULL will be copied. |
80a0a1a9 MW |
1897 | * |
1898 | * The entries returned may not represent a snapshot of the XArray at a | |
1899 | * moment in time. For example, if another thread stores to index 5, then | |
1900 | * index 10, calling xa_extract() may return the old contents of index 5 | |
1901 | * and the new contents of index 10. Indices not modified while this | |
1902 | * function is running will not be skipped. | |
1903 | * | |
1904 | * If you need stronger guarantees, holding the xa_lock across calls to this | |
1905 | * function will prevent concurrent modification. | |
1906 | * | |
1907 | * Context: Any context. Takes and releases the RCU lock. | |
1908 | * Return: The number of entries copied. | |
1909 | */ | |
1910 | unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, | |
1911 | unsigned long max, unsigned int n, xa_mark_t filter) | |
1912 | { | |
1913 | XA_STATE(xas, xa, start); | |
1914 | ||
1915 | if (!n) | |
1916 | return 0; | |
1917 | ||
1918 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
1919 | return xas_extract_marked(&xas, dst, max, n, filter); | |
1920 | return xas_extract_present(&xas, dst, max, n); | |
1921 | } | |
1922 | EXPORT_SYMBOL(xa_extract); | |
1923 | ||
687149fc MW |
1924 | /** |
1925 | * xa_destroy() - Free all internal data structures. | |
1926 | * @xa: XArray. | |
1927 | * | |
1928 | * After calling this function, the XArray is empty and has freed all memory | |
1929 | * allocated for its internal data structures. You are responsible for | |
1930 | * freeing the objects referenced by the XArray. | |
1931 | * | |
1932 | * Context: Any context. Takes and releases the xa_lock, interrupt-safe. | |
1933 | */ | |
1934 | void xa_destroy(struct xarray *xa) | |
1935 | { | |
1936 | XA_STATE(xas, xa, 0); | |
1937 | unsigned long flags; | |
1938 | void *entry; | |
1939 | ||
1940 | xas.xa_node = NULL; | |
1941 | xas_lock_irqsave(&xas, flags); | |
1942 | entry = xa_head_locked(xa); | |
1943 | RCU_INIT_POINTER(xa->xa_head, NULL); | |
1944 | xas_init_marks(&xas); | |
1945 | /* lockdep checks we're still holding the lock in xas_free_nodes() */ | |
1946 | if (xa_is_node(entry)) | |
1947 | xas_free_nodes(&xas, xa_to_node(entry)); | |
1948 | xas_unlock_irqrestore(&xas, flags); | |
1949 | } | |
1950 | EXPORT_SYMBOL(xa_destroy); | |
1951 | ||
ad3d6c72 MW |
1952 | #ifdef XA_DEBUG |
1953 | void xa_dump_node(const struct xa_node *node) | |
1954 | { | |
1955 | unsigned i, j; | |
1956 | ||
1957 | if (!node) | |
1958 | return; | |
1959 | if ((unsigned long)node & 3) { | |
1960 | pr_cont("node %px\n", node); | |
1961 | return; | |
1962 | } | |
1963 | ||
1964 | pr_cont("node %px %s %d parent %px shift %d count %d values %d " | |
1965 | "array %px list %px %px marks", | |
1966 | node, node->parent ? "offset" : "max", node->offset, | |
1967 | node->parent, node->shift, node->count, node->nr_values, | |
1968 | node->array, node->private_list.prev, node->private_list.next); | |
1969 | for (i = 0; i < XA_MAX_MARKS; i++) | |
1970 | for (j = 0; j < XA_MARK_LONGS; j++) | |
1971 | pr_cont(" %lx", node->marks[i][j]); | |
1972 | pr_cont("\n"); | |
1973 | } | |
1974 | ||
1975 | void xa_dump_index(unsigned long index, unsigned int shift) | |
1976 | { | |
1977 | if (!shift) | |
1978 | pr_info("%lu: ", index); | |
1979 | else if (shift >= BITS_PER_LONG) | |
1980 | pr_info("0-%lu: ", ~0UL); | |
1981 | else | |
1982 | pr_info("%lu-%lu: ", index, index | ((1UL << shift) - 1)); | |
1983 | } | |
1984 | ||
1985 | void xa_dump_entry(const void *entry, unsigned long index, unsigned long shift) | |
1986 | { | |
1987 | if (!entry) | |
1988 | return; | |
1989 | ||
1990 | xa_dump_index(index, shift); | |
1991 | ||
1992 | if (xa_is_node(entry)) { | |
1993 | if (shift == 0) { | |
1994 | pr_cont("%px\n", entry); | |
1995 | } else { | |
1996 | unsigned long i; | |
1997 | struct xa_node *node = xa_to_node(entry); | |
1998 | xa_dump_node(node); | |
1999 | for (i = 0; i < XA_CHUNK_SIZE; i++) | |
2000 | xa_dump_entry(node->slots[i], | |
2001 | index + (i << node->shift), node->shift); | |
2002 | } | |
2003 | } else if (xa_is_value(entry)) | |
2004 | pr_cont("value %ld (0x%lx) [%px]\n", xa_to_value(entry), | |
2005 | xa_to_value(entry), entry); | |
2006 | else if (!xa_is_internal(entry)) | |
2007 | pr_cont("%px\n", entry); | |
2008 | else if (xa_is_retry(entry)) | |
2009 | pr_cont("retry (%ld)\n", xa_to_internal(entry)); | |
2010 | else if (xa_is_sibling(entry)) | |
2011 | pr_cont("sibling (slot %ld)\n", xa_to_sibling(entry)); | |
9f14d4f1 MW |
2012 | else if (xa_is_zero(entry)) |
2013 | pr_cont("zero (%ld)\n", xa_to_internal(entry)); | |
ad3d6c72 MW |
2014 | else |
2015 | pr_cont("UNKNOWN ENTRY (%px)\n", entry); | |
2016 | } | |
2017 | ||
2018 | void xa_dump(const struct xarray *xa) | |
2019 | { | |
2020 | void *entry = xa->xa_head; | |
2021 | unsigned int shift = 0; | |
2022 | ||
2023 | pr_info("xarray: %px head %px flags %x marks %d %d %d\n", xa, entry, | |
9b89a035 MW |
2024 | xa->xa_flags, xa_marked(xa, XA_MARK_0), |
2025 | xa_marked(xa, XA_MARK_1), xa_marked(xa, XA_MARK_2)); | |
ad3d6c72 MW |
2026 | if (xa_is_node(entry)) |
2027 | shift = xa_to_node(entry)->shift + XA_CHUNK_SHIFT; | |
2028 | xa_dump_entry(entry, 0, shift); | |
2029 | } | |
2030 | #endif |