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f8d5d0cc MW |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * XArray implementation | |
c44aa5e8 MWO |
4 | * Copyright (c) 2017-2018 Microsoft Corporation |
5 | * Copyright (c) 2018-2020 Oracle | |
f8d5d0cc MW |
6 | * Author: Matthew Wilcox <[email protected]> |
7 | */ | |
8 | ||
9b89a035 | 9 | #include <linux/bitmap.h> |
f8d5d0cc | 10 | #include <linux/export.h> |
58d6ea30 MW |
11 | #include <linux/list.h> |
12 | #include <linux/slab.h> | |
f8d5d0cc MW |
13 | #include <linux/xarray.h> |
14 | ||
15 | /* | |
16 | * Coding conventions in this file: | |
17 | * | |
18 | * @xa is used to refer to the entire xarray. | |
19 | * @xas is the 'xarray operation state'. It may be either a pointer to | |
20 | * an xa_state, or an xa_state stored on the stack. This is an unfortunate | |
21 | * ambiguity. | |
22 | * @index is the index of the entry being operated on | |
23 | * @mark is an xa_mark_t; a small number indicating one of the mark bits. | |
24 | * @node refers to an xa_node; usually the primary one being operated on by | |
25 | * this function. | |
26 | * @offset is the index into the slots array inside an xa_node. | |
27 | * @parent refers to the @xa_node closer to the head than @node. | |
28 | * @entry refers to something stored in a slot in the xarray | |
29 | */ | |
30 | ||
58d6ea30 MW |
31 | static inline unsigned int xa_lock_type(const struct xarray *xa) |
32 | { | |
33 | return (__force unsigned int)xa->xa_flags & 3; | |
34 | } | |
35 | ||
36 | static inline void xas_lock_type(struct xa_state *xas, unsigned int lock_type) | |
37 | { | |
38 | if (lock_type == XA_LOCK_IRQ) | |
39 | xas_lock_irq(xas); | |
40 | else if (lock_type == XA_LOCK_BH) | |
41 | xas_lock_bh(xas); | |
42 | else | |
43 | xas_lock(xas); | |
44 | } | |
45 | ||
46 | static inline void xas_unlock_type(struct xa_state *xas, unsigned int lock_type) | |
47 | { | |
48 | if (lock_type == XA_LOCK_IRQ) | |
49 | xas_unlock_irq(xas); | |
50 | else if (lock_type == XA_LOCK_BH) | |
51 | xas_unlock_bh(xas); | |
52 | else | |
53 | xas_unlock(xas); | |
54 | } | |
55 | ||
371c752d MW |
56 | static inline bool xa_track_free(const struct xarray *xa) |
57 | { | |
58 | return xa->xa_flags & XA_FLAGS_TRACK_FREE; | |
59 | } | |
60 | ||
3ccaf57a MW |
61 | static inline bool xa_zero_busy(const struct xarray *xa) |
62 | { | |
63 | return xa->xa_flags & XA_FLAGS_ZERO_BUSY; | |
64 | } | |
65 | ||
9b89a035 MW |
66 | static inline void xa_mark_set(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 void xa_mark_clear(struct xarray *xa, xa_mark_t mark) | |
73 | { | |
74 | if (xa->xa_flags & XA_FLAGS_MARK(mark)) | |
75 | xa->xa_flags &= ~(XA_FLAGS_MARK(mark)); | |
76 | } | |
77 | ||
78 | static inline unsigned long *node_marks(struct xa_node *node, xa_mark_t mark) | |
79 | { | |
80 | return node->marks[(__force unsigned)mark]; | |
81 | } | |
82 | ||
83 | static inline bool node_get_mark(struct xa_node *node, | |
84 | unsigned int offset, xa_mark_t mark) | |
85 | { | |
86 | return test_bit(offset, node_marks(node, mark)); | |
87 | } | |
88 | ||
89 | /* returns true if the bit was set */ | |
90 | static inline bool node_set_mark(struct xa_node *node, unsigned int offset, | |
91 | xa_mark_t mark) | |
92 | { | |
93 | return __test_and_set_bit(offset, node_marks(node, mark)); | |
94 | } | |
95 | ||
96 | /* returns true if the bit was set */ | |
97 | static inline bool node_clear_mark(struct xa_node *node, unsigned int offset, | |
98 | xa_mark_t mark) | |
99 | { | |
100 | return __test_and_clear_bit(offset, node_marks(node, mark)); | |
101 | } | |
102 | ||
103 | static inline bool node_any_mark(struct xa_node *node, xa_mark_t mark) | |
104 | { | |
105 | return !bitmap_empty(node_marks(node, mark), XA_CHUNK_SIZE); | |
106 | } | |
107 | ||
371c752d MW |
108 | static inline void node_mark_all(struct xa_node *node, xa_mark_t mark) |
109 | { | |
110 | bitmap_fill(node_marks(node, mark), XA_CHUNK_SIZE); | |
111 | } | |
112 | ||
58d6ea30 MW |
113 | #define mark_inc(mark) do { \ |
114 | mark = (__force xa_mark_t)((__force unsigned)(mark) + 1); \ | |
115 | } while (0) | |
116 | ||
117 | /* | |
118 | * xas_squash_marks() - Merge all marks to the first entry | |
119 | * @xas: Array operation state. | |
120 | * | |
121 | * Set a mark on the first entry if any entry has it set. Clear marks on | |
122 | * all sibling entries. | |
123 | */ | |
124 | static void xas_squash_marks(const struct xa_state *xas) | |
125 | { | |
126 | unsigned int mark = 0; | |
127 | unsigned int limit = xas->xa_offset + xas->xa_sibs + 1; | |
128 | ||
129 | if (!xas->xa_sibs) | |
130 | return; | |
131 | ||
132 | do { | |
133 | unsigned long *marks = xas->xa_node->marks[mark]; | |
134 | if (find_next_bit(marks, limit, xas->xa_offset + 1) == limit) | |
135 | continue; | |
136 | __set_bit(xas->xa_offset, marks); | |
137 | bitmap_clear(marks, xas->xa_offset + 1, xas->xa_sibs); | |
138 | } while (mark++ != (__force unsigned)XA_MARK_MAX); | |
139 | } | |
140 | ||
ad3d6c72 MW |
141 | /* extracts the offset within this node from the index */ |
142 | static unsigned int get_offset(unsigned long index, struct xa_node *node) | |
143 | { | |
144 | return (index >> node->shift) & XA_CHUNK_MASK; | |
145 | } | |
146 | ||
b803b428 MW |
147 | static void xas_set_offset(struct xa_state *xas) |
148 | { | |
149 | xas->xa_offset = get_offset(xas->xa_index, xas->xa_node); | |
150 | } | |
151 | ||
ad3d6c72 MW |
152 | /* move the index either forwards (find) or backwards (sibling slot) */ |
153 | static void xas_move_index(struct xa_state *xas, unsigned long offset) | |
154 | { | |
155 | unsigned int shift = xas->xa_node->shift; | |
156 | xas->xa_index &= ~XA_CHUNK_MASK << shift; | |
157 | xas->xa_index += offset << shift; | |
158 | } | |
159 | ||
b803b428 MW |
160 | static void xas_advance(struct xa_state *xas) |
161 | { | |
162 | xas->xa_offset++; | |
163 | xas_move_index(xas, xas->xa_offset); | |
164 | } | |
165 | ||
ad3d6c72 MW |
166 | static void *set_bounds(struct xa_state *xas) |
167 | { | |
168 | xas->xa_node = XAS_BOUNDS; | |
169 | return NULL; | |
170 | } | |
171 | ||
172 | /* | |
173 | * Starts a walk. If the @xas is already valid, we assume that it's on | |
174 | * the right path and just return where we've got to. If we're in an | |
175 | * error state, return NULL. If the index is outside the current scope | |
176 | * of the xarray, return NULL without changing @xas->xa_node. Otherwise | |
177 | * set @xas->xa_node to NULL and return the current head of the array. | |
178 | */ | |
179 | static void *xas_start(struct xa_state *xas) | |
180 | { | |
181 | void *entry; | |
182 | ||
183 | if (xas_valid(xas)) | |
184 | return xas_reload(xas); | |
185 | if (xas_error(xas)) | |
186 | return NULL; | |
187 | ||
188 | entry = xa_head(xas->xa); | |
189 | if (!xa_is_node(entry)) { | |
190 | if (xas->xa_index) | |
191 | return set_bounds(xas); | |
192 | } else { | |
193 | if ((xas->xa_index >> xa_to_node(entry)->shift) > XA_CHUNK_MASK) | |
194 | return set_bounds(xas); | |
195 | } | |
196 | ||
197 | xas->xa_node = NULL; | |
198 | return entry; | |
199 | } | |
200 | ||
201 | static void *xas_descend(struct xa_state *xas, struct xa_node *node) | |
202 | { | |
203 | unsigned int offset = get_offset(xas->xa_index, node); | |
204 | void *entry = xa_entry(xas->xa, node, offset); | |
205 | ||
206 | xas->xa_node = node; | |
207 | if (xa_is_sibling(entry)) { | |
208 | offset = xa_to_sibling(entry); | |
209 | entry = xa_entry(xas->xa, node, offset); | |
210 | } | |
211 | ||
212 | xas->xa_offset = offset; | |
213 | return entry; | |
214 | } | |
215 | ||
216 | /** | |
217 | * xas_load() - Load an entry from the XArray (advanced). | |
218 | * @xas: XArray operation state. | |
219 | * | |
220 | * Usually walks the @xas to the appropriate state to load the entry | |
221 | * stored at xa_index. However, it will do nothing and return %NULL if | |
222 | * @xas is in an error state. xas_load() will never expand the tree. | |
223 | * | |
224 | * If the xa_state is set up to operate on a multi-index entry, xas_load() | |
225 | * may return %NULL or an internal entry, even if there are entries | |
226 | * present within the range specified by @xas. | |
227 | * | |
228 | * Context: Any context. The caller should hold the xa_lock or the RCU lock. | |
229 | * Return: Usually an entry in the XArray, but see description for exceptions. | |
230 | */ | |
231 | void *xas_load(struct xa_state *xas) | |
232 | { | |
233 | void *entry = xas_start(xas); | |
234 | ||
235 | while (xa_is_node(entry)) { | |
236 | struct xa_node *node = xa_to_node(entry); | |
237 | ||
238 | if (xas->xa_shift > node->shift) | |
239 | break; | |
240 | entry = xas_descend(xas, node); | |
76b4e529 MW |
241 | if (node->shift == 0) |
242 | break; | |
ad3d6c72 MW |
243 | } |
244 | return entry; | |
245 | } | |
246 | EXPORT_SYMBOL_GPL(xas_load); | |
247 | ||
58d6ea30 MW |
248 | /* Move the radix tree node cache here */ |
249 | extern struct kmem_cache *radix_tree_node_cachep; | |
250 | extern void radix_tree_node_rcu_free(struct rcu_head *head); | |
251 | ||
252 | #define XA_RCU_FREE ((struct xarray *)1) | |
253 | ||
254 | static void xa_node_free(struct xa_node *node) | |
255 | { | |
256 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
257 | node->array = XA_RCU_FREE; | |
258 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); | |
259 | } | |
260 | ||
261 | /* | |
262 | * xas_destroy() - Free any resources allocated during the XArray operation. | |
263 | * @xas: XArray operation state. | |
264 | * | |
265 | * This function is now internal-only. | |
266 | */ | |
267 | static void xas_destroy(struct xa_state *xas) | |
268 | { | |
8fc75643 | 269 | struct xa_node *next, *node = xas->xa_alloc; |
58d6ea30 | 270 | |
8fc75643 MWO |
271 | while (node) { |
272 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
273 | next = rcu_dereference_raw(node->parent); | |
274 | radix_tree_node_rcu_free(&node->rcu_head); | |
275 | xas->xa_alloc = node = next; | |
276 | } | |
58d6ea30 MW |
277 | } |
278 | ||
279 | /** | |
280 | * xas_nomem() - Allocate memory if needed. | |
281 | * @xas: XArray operation state. | |
282 | * @gfp: Memory allocation flags. | |
283 | * | |
284 | * If we need to add new nodes to the XArray, we try to allocate memory | |
285 | * with GFP_NOWAIT while holding the lock, which will usually succeed. | |
286 | * If it fails, @xas is flagged as needing memory to continue. The caller | |
287 | * should drop the lock and call xas_nomem(). If xas_nomem() succeeds, | |
288 | * the caller should retry the operation. | |
289 | * | |
290 | * Forward progress is guaranteed as one node is allocated here and | |
291 | * stored in the xa_state where it will be found by xas_alloc(). More | |
292 | * nodes will likely be found in the slab allocator, but we do not tie | |
293 | * them up here. | |
294 | * | |
295 | * Return: true if memory was needed, and was successfully allocated. | |
296 | */ | |
297 | bool xas_nomem(struct xa_state *xas, gfp_t gfp) | |
298 | { | |
299 | if (xas->xa_node != XA_ERROR(-ENOMEM)) { | |
300 | xas_destroy(xas); | |
301 | return false; | |
302 | } | |
7b785645 JW |
303 | if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT) |
304 | gfp |= __GFP_ACCOUNT; | |
58d6ea30 MW |
305 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); |
306 | if (!xas->xa_alloc) | |
307 | return false; | |
8fc75643 | 308 | xas->xa_alloc->parent = NULL; |
58d6ea30 MW |
309 | XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); |
310 | xas->xa_node = XAS_RESTART; | |
311 | return true; | |
312 | } | |
313 | EXPORT_SYMBOL_GPL(xas_nomem); | |
314 | ||
315 | /* | |
316 | * __xas_nomem() - Drop locks and allocate memory if needed. | |
317 | * @xas: XArray operation state. | |
318 | * @gfp: Memory allocation flags. | |
319 | * | |
320 | * Internal variant of xas_nomem(). | |
321 | * | |
322 | * Return: true if memory was needed, and was successfully allocated. | |
323 | */ | |
324 | static bool __xas_nomem(struct xa_state *xas, gfp_t gfp) | |
325 | __must_hold(xas->xa->xa_lock) | |
326 | { | |
327 | unsigned int lock_type = xa_lock_type(xas->xa); | |
328 | ||
329 | if (xas->xa_node != XA_ERROR(-ENOMEM)) { | |
330 | xas_destroy(xas); | |
331 | return false; | |
332 | } | |
7b785645 JW |
333 | if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT) |
334 | gfp |= __GFP_ACCOUNT; | |
58d6ea30 MW |
335 | if (gfpflags_allow_blocking(gfp)) { |
336 | xas_unlock_type(xas, lock_type); | |
337 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
338 | xas_lock_type(xas, lock_type); | |
339 | } else { | |
340 | xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
341 | } | |
342 | if (!xas->xa_alloc) | |
343 | return false; | |
8fc75643 | 344 | xas->xa_alloc->parent = NULL; |
58d6ea30 MW |
345 | XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); |
346 | xas->xa_node = XAS_RESTART; | |
347 | return true; | |
348 | } | |
349 | ||
350 | static void xas_update(struct xa_state *xas, struct xa_node *node) | |
351 | { | |
352 | if (xas->xa_update) | |
353 | xas->xa_update(node); | |
354 | else | |
355 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
356 | } | |
357 | ||
358 | static void *xas_alloc(struct xa_state *xas, unsigned int shift) | |
359 | { | |
360 | struct xa_node *parent = xas->xa_node; | |
361 | struct xa_node *node = xas->xa_alloc; | |
362 | ||
363 | if (xas_invalid(xas)) | |
364 | return NULL; | |
365 | ||
366 | if (node) { | |
367 | xas->xa_alloc = NULL; | |
368 | } else { | |
7b785645 JW |
369 | gfp_t gfp = GFP_NOWAIT | __GFP_NOWARN; |
370 | ||
371 | if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT) | |
372 | gfp |= __GFP_ACCOUNT; | |
373 | ||
374 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
58d6ea30 MW |
375 | if (!node) { |
376 | xas_set_err(xas, -ENOMEM); | |
377 | return NULL; | |
378 | } | |
379 | } | |
380 | ||
381 | if (parent) { | |
382 | node->offset = xas->xa_offset; | |
383 | parent->count++; | |
384 | XA_NODE_BUG_ON(node, parent->count > XA_CHUNK_SIZE); | |
385 | xas_update(xas, parent); | |
386 | } | |
387 | XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); | |
388 | XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); | |
389 | node->shift = shift; | |
390 | node->count = 0; | |
391 | node->nr_values = 0; | |
392 | RCU_INIT_POINTER(node->parent, xas->xa_node); | |
393 | node->array = xas->xa; | |
394 | ||
395 | return node; | |
396 | } | |
397 | ||
0e9446c3 MW |
398 | #ifdef CONFIG_XARRAY_MULTI |
399 | /* Returns the number of indices covered by a given xa_state */ | |
400 | static unsigned long xas_size(const struct xa_state *xas) | |
401 | { | |
402 | return (xas->xa_sibs + 1UL) << xas->xa_shift; | |
403 | } | |
404 | #endif | |
405 | ||
58d6ea30 MW |
406 | /* |
407 | * Use this to calculate the maximum index that will need to be created | |
408 | * in order to add the entry described by @xas. Because we cannot store a | |
8fc75643 | 409 | * multi-index entry at index 0, the calculation is a little more complex |
58d6ea30 MW |
410 | * than you might expect. |
411 | */ | |
412 | static unsigned long xas_max(struct xa_state *xas) | |
413 | { | |
414 | unsigned long max = xas->xa_index; | |
415 | ||
416 | #ifdef CONFIG_XARRAY_MULTI | |
417 | if (xas->xa_shift || xas->xa_sibs) { | |
0e9446c3 | 418 | unsigned long mask = xas_size(xas) - 1; |
58d6ea30 MW |
419 | max |= mask; |
420 | if (mask == max) | |
421 | max++; | |
422 | } | |
423 | #endif | |
424 | ||
425 | return max; | |
426 | } | |
427 | ||
428 | /* The maximum index that can be contained in the array without expanding it */ | |
429 | static unsigned long max_index(void *entry) | |
430 | { | |
431 | if (!xa_is_node(entry)) | |
432 | return 0; | |
433 | return (XA_CHUNK_SIZE << xa_to_node(entry)->shift) - 1; | |
434 | } | |
435 | ||
436 | static void xas_shrink(struct xa_state *xas) | |
437 | { | |
438 | struct xarray *xa = xas->xa; | |
439 | struct xa_node *node = xas->xa_node; | |
440 | ||
441 | for (;;) { | |
442 | void *entry; | |
443 | ||
444 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
445 | if (node->count != 1) | |
446 | break; | |
447 | entry = xa_entry_locked(xa, node, 0); | |
448 | if (!entry) | |
449 | break; | |
450 | if (!xa_is_node(entry) && node->shift) | |
451 | break; | |
3ccaf57a MW |
452 | if (xa_is_zero(entry) && xa_zero_busy(xa)) |
453 | entry = NULL; | |
58d6ea30 MW |
454 | xas->xa_node = XAS_BOUNDS; |
455 | ||
456 | RCU_INIT_POINTER(xa->xa_head, entry); | |
371c752d MW |
457 | if (xa_track_free(xa) && !node_get_mark(node, 0, XA_FREE_MARK)) |
458 | xa_mark_clear(xa, XA_FREE_MARK); | |
58d6ea30 MW |
459 | |
460 | node->count = 0; | |
461 | node->nr_values = 0; | |
462 | if (!xa_is_node(entry)) | |
463 | RCU_INIT_POINTER(node->slots[0], XA_RETRY_ENTRY); | |
464 | xas_update(xas, node); | |
465 | xa_node_free(node); | |
466 | if (!xa_is_node(entry)) | |
467 | break; | |
468 | node = xa_to_node(entry); | |
469 | node->parent = NULL; | |
470 | } | |
471 | } | |
472 | ||
473 | /* | |
474 | * xas_delete_node() - Attempt to delete an xa_node | |
475 | * @xas: Array operation state. | |
476 | * | |
477 | * Attempts to delete the @xas->xa_node. This will fail if xa->node has | |
478 | * a non-zero reference count. | |
479 | */ | |
480 | static void xas_delete_node(struct xa_state *xas) | |
481 | { | |
482 | struct xa_node *node = xas->xa_node; | |
483 | ||
484 | for (;;) { | |
485 | struct xa_node *parent; | |
486 | ||
487 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
488 | if (node->count) | |
489 | break; | |
490 | ||
491 | parent = xa_parent_locked(xas->xa, node); | |
492 | xas->xa_node = parent; | |
493 | xas->xa_offset = node->offset; | |
494 | xa_node_free(node); | |
495 | ||
496 | if (!parent) { | |
497 | xas->xa->xa_head = NULL; | |
498 | xas->xa_node = XAS_BOUNDS; | |
499 | return; | |
500 | } | |
501 | ||
502 | parent->slots[xas->xa_offset] = NULL; | |
503 | parent->count--; | |
504 | XA_NODE_BUG_ON(parent, parent->count > XA_CHUNK_SIZE); | |
505 | node = parent; | |
506 | xas_update(xas, node); | |
507 | } | |
508 | ||
509 | if (!node->parent) | |
510 | xas_shrink(xas); | |
511 | } | |
512 | ||
513 | /** | |
514 | * xas_free_nodes() - Free this node and all nodes that it references | |
515 | * @xas: Array operation state. | |
516 | * @top: Node to free | |
517 | * | |
518 | * This node has been removed from the tree. We must now free it and all | |
519 | * of its subnodes. There may be RCU walkers with references into the tree, | |
520 | * so we must replace all entries with retry markers. | |
521 | */ | |
522 | static void xas_free_nodes(struct xa_state *xas, struct xa_node *top) | |
523 | { | |
524 | unsigned int offset = 0; | |
525 | struct xa_node *node = top; | |
526 | ||
527 | for (;;) { | |
528 | void *entry = xa_entry_locked(xas->xa, node, offset); | |
529 | ||
76b4e529 | 530 | if (node->shift && xa_is_node(entry)) { |
58d6ea30 MW |
531 | node = xa_to_node(entry); |
532 | offset = 0; | |
533 | continue; | |
534 | } | |
535 | if (entry) | |
536 | RCU_INIT_POINTER(node->slots[offset], XA_RETRY_ENTRY); | |
537 | offset++; | |
538 | while (offset == XA_CHUNK_SIZE) { | |
539 | struct xa_node *parent; | |
540 | ||
541 | parent = xa_parent_locked(xas->xa, node); | |
542 | offset = node->offset + 1; | |
543 | node->count = 0; | |
544 | node->nr_values = 0; | |
545 | xas_update(xas, node); | |
546 | xa_node_free(node); | |
547 | if (node == top) | |
548 | return; | |
549 | node = parent; | |
550 | } | |
551 | } | |
552 | } | |
553 | ||
554 | /* | |
555 | * xas_expand adds nodes to the head of the tree until it has reached | |
556 | * sufficient height to be able to contain @xas->xa_index | |
557 | */ | |
558 | static int xas_expand(struct xa_state *xas, void *head) | |
559 | { | |
560 | struct xarray *xa = xas->xa; | |
561 | struct xa_node *node = NULL; | |
562 | unsigned int shift = 0; | |
563 | unsigned long max = xas_max(xas); | |
564 | ||
565 | if (!head) { | |
566 | if (max == 0) | |
567 | return 0; | |
568 | while ((max >> shift) >= XA_CHUNK_SIZE) | |
569 | shift += XA_CHUNK_SHIFT; | |
570 | return shift + XA_CHUNK_SHIFT; | |
571 | } else if (xa_is_node(head)) { | |
572 | node = xa_to_node(head); | |
573 | shift = node->shift + XA_CHUNK_SHIFT; | |
574 | } | |
575 | xas->xa_node = NULL; | |
576 | ||
577 | while (max > max_index(head)) { | |
578 | xa_mark_t mark = 0; | |
579 | ||
580 | XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); | |
581 | node = xas_alloc(xas, shift); | |
582 | if (!node) | |
583 | return -ENOMEM; | |
584 | ||
585 | node->count = 1; | |
586 | if (xa_is_value(head)) | |
587 | node->nr_values = 1; | |
588 | RCU_INIT_POINTER(node->slots[0], head); | |
589 | ||
590 | /* Propagate the aggregated mark info to the new child */ | |
591 | for (;;) { | |
371c752d MW |
592 | if (xa_track_free(xa) && mark == XA_FREE_MARK) { |
593 | node_mark_all(node, XA_FREE_MARK); | |
594 | if (!xa_marked(xa, XA_FREE_MARK)) { | |
595 | node_clear_mark(node, 0, XA_FREE_MARK); | |
596 | xa_mark_set(xa, XA_FREE_MARK); | |
597 | } | |
598 | } else if (xa_marked(xa, mark)) { | |
58d6ea30 | 599 | node_set_mark(node, 0, mark); |
371c752d | 600 | } |
58d6ea30 MW |
601 | if (mark == XA_MARK_MAX) |
602 | break; | |
603 | mark_inc(mark); | |
604 | } | |
605 | ||
606 | /* | |
607 | * Now that the new node is fully initialised, we can add | |
608 | * it to the tree | |
609 | */ | |
610 | if (xa_is_node(head)) { | |
611 | xa_to_node(head)->offset = 0; | |
612 | rcu_assign_pointer(xa_to_node(head)->parent, node); | |
613 | } | |
614 | head = xa_mk_node(node); | |
615 | rcu_assign_pointer(xa->xa_head, head); | |
616 | xas_update(xas, node); | |
617 | ||
618 | shift += XA_CHUNK_SHIFT; | |
619 | } | |
620 | ||
621 | xas->xa_node = node; | |
622 | return shift; | |
623 | } | |
624 | ||
625 | /* | |
626 | * xas_create() - Create a slot to store an entry in. | |
627 | * @xas: XArray operation state. | |
76b4e529 | 628 | * @allow_root: %true if we can store the entry in the root directly |
58d6ea30 MW |
629 | * |
630 | * Most users will not need to call this function directly, as it is called | |
631 | * by xas_store(). It is useful for doing conditional store operations | |
632 | * (see the xa_cmpxchg() implementation for an example). | |
633 | * | |
634 | * Return: If the slot already existed, returns the contents of this slot. | |
804dfaf0 MW |
635 | * If the slot was newly created, returns %NULL. If it failed to create the |
636 | * slot, returns %NULL and indicates the error in @xas. | |
58d6ea30 | 637 | */ |
76b4e529 | 638 | static void *xas_create(struct xa_state *xas, bool allow_root) |
58d6ea30 MW |
639 | { |
640 | struct xarray *xa = xas->xa; | |
641 | void *entry; | |
642 | void __rcu **slot; | |
643 | struct xa_node *node = xas->xa_node; | |
644 | int shift; | |
645 | unsigned int order = xas->xa_shift; | |
646 | ||
647 | if (xas_top(node)) { | |
648 | entry = xa_head_locked(xa); | |
649 | xas->xa_node = NULL; | |
3ccaf57a MW |
650 | if (!entry && xa_zero_busy(xa)) |
651 | entry = XA_ZERO_ENTRY; | |
58d6ea30 MW |
652 | shift = xas_expand(xas, entry); |
653 | if (shift < 0) | |
654 | return NULL; | |
76b4e529 MW |
655 | if (!shift && !allow_root) |
656 | shift = XA_CHUNK_SHIFT; | |
58d6ea30 MW |
657 | entry = xa_head_locked(xa); |
658 | slot = &xa->xa_head; | |
659 | } else if (xas_error(xas)) { | |
660 | return NULL; | |
661 | } else if (node) { | |
662 | unsigned int offset = xas->xa_offset; | |
663 | ||
664 | shift = node->shift; | |
665 | entry = xa_entry_locked(xa, node, offset); | |
666 | slot = &node->slots[offset]; | |
667 | } else { | |
668 | shift = 0; | |
669 | entry = xa_head_locked(xa); | |
670 | slot = &xa->xa_head; | |
671 | } | |
672 | ||
673 | while (shift > order) { | |
674 | shift -= XA_CHUNK_SHIFT; | |
675 | if (!entry) { | |
676 | node = xas_alloc(xas, shift); | |
677 | if (!node) | |
678 | break; | |
371c752d MW |
679 | if (xa_track_free(xa)) |
680 | node_mark_all(node, XA_FREE_MARK); | |
58d6ea30 MW |
681 | rcu_assign_pointer(*slot, xa_mk_node(node)); |
682 | } else if (xa_is_node(entry)) { | |
683 | node = xa_to_node(entry); | |
684 | } else { | |
685 | break; | |
686 | } | |
687 | entry = xas_descend(xas, node); | |
688 | slot = &node->slots[xas->xa_offset]; | |
689 | } | |
690 | ||
691 | return entry; | |
692 | } | |
693 | ||
2264f513 MW |
694 | /** |
695 | * xas_create_range() - Ensure that stores to this range will succeed | |
696 | * @xas: XArray operation state. | |
697 | * | |
698 | * Creates all of the slots in the range covered by @xas. Sets @xas to | |
699 | * create single-index entries and positions it at the beginning of the | |
700 | * range. This is for the benefit of users which have not yet been | |
701 | * converted to use multi-index entries. | |
702 | */ | |
703 | void xas_create_range(struct xa_state *xas) | |
704 | { | |
705 | unsigned long index = xas->xa_index; | |
706 | unsigned char shift = xas->xa_shift; | |
707 | unsigned char sibs = xas->xa_sibs; | |
708 | ||
84c34df1 | 709 | xas->xa_index |= ((sibs + 1UL) << shift) - 1; |
2264f513 MW |
710 | if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift) |
711 | xas->xa_offset |= sibs; | |
712 | xas->xa_shift = 0; | |
713 | xas->xa_sibs = 0; | |
714 | ||
715 | for (;;) { | |
76b4e529 | 716 | xas_create(xas, true); |
2264f513 MW |
717 | if (xas_error(xas)) |
718 | goto restore; | |
719 | if (xas->xa_index <= (index | XA_CHUNK_MASK)) | |
720 | goto success; | |
721 | xas->xa_index -= XA_CHUNK_SIZE; | |
722 | ||
723 | for (;;) { | |
724 | struct xa_node *node = xas->xa_node; | |
725 | xas->xa_node = xa_parent_locked(xas->xa, node); | |
726 | xas->xa_offset = node->offset - 1; | |
727 | if (node->offset != 0) | |
728 | break; | |
729 | } | |
730 | } | |
731 | ||
732 | restore: | |
733 | xas->xa_shift = shift; | |
734 | xas->xa_sibs = sibs; | |
735 | xas->xa_index = index; | |
736 | return; | |
737 | success: | |
738 | xas->xa_index = index; | |
739 | if (xas->xa_node) | |
740 | xas_set_offset(xas); | |
741 | } | |
742 | EXPORT_SYMBOL_GPL(xas_create_range); | |
743 | ||
58d6ea30 MW |
744 | static void update_node(struct xa_state *xas, struct xa_node *node, |
745 | int count, int values) | |
746 | { | |
747 | if (!node || (!count && !values)) | |
748 | return; | |
749 | ||
750 | node->count += count; | |
751 | node->nr_values += values; | |
752 | XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); | |
753 | XA_NODE_BUG_ON(node, node->nr_values > XA_CHUNK_SIZE); | |
754 | xas_update(xas, node); | |
755 | if (count < 0) | |
756 | xas_delete_node(xas); | |
757 | } | |
758 | ||
759 | /** | |
760 | * xas_store() - Store this entry in the XArray. | |
761 | * @xas: XArray operation state. | |
762 | * @entry: New entry. | |
763 | * | |
764 | * If @xas is operating on a multi-index entry, the entry returned by this | |
765 | * function is essentially meaningless (it may be an internal entry or it | |
766 | * may be %NULL, even if there are non-NULL entries at some of the indices | |
767 | * covered by the range). This is not a problem for any current users, | |
768 | * and can be changed if needed. | |
769 | * | |
770 | * Return: The old entry at this index. | |
771 | */ | |
772 | void *xas_store(struct xa_state *xas, void *entry) | |
773 | { | |
774 | struct xa_node *node; | |
775 | void __rcu **slot = &xas->xa->xa_head; | |
776 | unsigned int offset, max; | |
777 | int count = 0; | |
778 | int values = 0; | |
779 | void *first, *next; | |
780 | bool value = xa_is_value(entry); | |
781 | ||
4a5c8d89 MW |
782 | if (entry) { |
783 | bool allow_root = !xa_is_node(entry) && !xa_is_zero(entry); | |
784 | first = xas_create(xas, allow_root); | |
785 | } else { | |
58d6ea30 | 786 | first = xas_load(xas); |
4a5c8d89 | 787 | } |
58d6ea30 MW |
788 | |
789 | if (xas_invalid(xas)) | |
790 | return first; | |
791 | node = xas->xa_node; | |
792 | if (node && (xas->xa_shift < node->shift)) | |
793 | xas->xa_sibs = 0; | |
794 | if ((first == entry) && !xas->xa_sibs) | |
795 | return first; | |
796 | ||
797 | next = first; | |
798 | offset = xas->xa_offset; | |
799 | max = xas->xa_offset + xas->xa_sibs; | |
800 | if (node) { | |
801 | slot = &node->slots[offset]; | |
802 | if (xas->xa_sibs) | |
803 | xas_squash_marks(xas); | |
804 | } | |
805 | if (!entry) | |
806 | xas_init_marks(xas); | |
807 | ||
808 | for (;;) { | |
809 | /* | |
810 | * Must clear the marks before setting the entry to NULL, | |
811 | * otherwise xas_for_each_marked may find a NULL entry and | |
812 | * stop early. rcu_assign_pointer contains a release barrier | |
813 | * so the mark clearing will appear to happen before the | |
814 | * entry is set to NULL. | |
815 | */ | |
816 | rcu_assign_pointer(*slot, entry); | |
2fbe967b | 817 | if (xa_is_node(next) && (!node || node->shift)) |
58d6ea30 MW |
818 | xas_free_nodes(xas, xa_to_node(next)); |
819 | if (!node) | |
820 | break; | |
821 | count += !next - !entry; | |
822 | values += !xa_is_value(first) - !value; | |
823 | if (entry) { | |
824 | if (offset == max) | |
825 | break; | |
826 | if (!xa_is_sibling(entry)) | |
827 | entry = xa_mk_sibling(xas->xa_offset); | |
828 | } else { | |
829 | if (offset == XA_CHUNK_MASK) | |
830 | break; | |
831 | } | |
832 | next = xa_entry_locked(xas->xa, node, ++offset); | |
833 | if (!xa_is_sibling(next)) { | |
834 | if (!entry && (offset > max)) | |
835 | break; | |
836 | first = next; | |
837 | } | |
838 | slot++; | |
839 | } | |
840 | ||
841 | update_node(xas, node, count, values); | |
842 | return first; | |
843 | } | |
844 | EXPORT_SYMBOL_GPL(xas_store); | |
845 | ||
9b89a035 MW |
846 | /** |
847 | * xas_get_mark() - Returns the state of this mark. | |
848 | * @xas: XArray operation state. | |
849 | * @mark: Mark number. | |
850 | * | |
851 | * Return: true if the mark is set, false if the mark is clear or @xas | |
852 | * is in an error state. | |
853 | */ | |
854 | bool xas_get_mark(const struct xa_state *xas, xa_mark_t mark) | |
855 | { | |
856 | if (xas_invalid(xas)) | |
857 | return false; | |
858 | if (!xas->xa_node) | |
859 | return xa_marked(xas->xa, mark); | |
860 | return node_get_mark(xas->xa_node, xas->xa_offset, mark); | |
861 | } | |
862 | EXPORT_SYMBOL_GPL(xas_get_mark); | |
863 | ||
864 | /** | |
865 | * xas_set_mark() - Sets the mark on this entry and its parents. | |
866 | * @xas: XArray operation state. | |
867 | * @mark: Mark number. | |
868 | * | |
869 | * Sets the specified mark on this entry, and walks up the tree setting it | |
870 | * on all the ancestor entries. Does nothing if @xas has not been walked to | |
871 | * an entry, or is in an error state. | |
872 | */ | |
873 | void xas_set_mark(const struct xa_state *xas, xa_mark_t mark) | |
874 | { | |
875 | struct xa_node *node = xas->xa_node; | |
876 | unsigned int offset = xas->xa_offset; | |
877 | ||
878 | if (xas_invalid(xas)) | |
879 | return; | |
880 | ||
881 | while (node) { | |
882 | if (node_set_mark(node, offset, mark)) | |
883 | return; | |
884 | offset = node->offset; | |
885 | node = xa_parent_locked(xas->xa, node); | |
886 | } | |
887 | ||
888 | if (!xa_marked(xas->xa, mark)) | |
889 | xa_mark_set(xas->xa, mark); | |
890 | } | |
891 | EXPORT_SYMBOL_GPL(xas_set_mark); | |
892 | ||
893 | /** | |
894 | * xas_clear_mark() - Clears the mark on this entry and its parents. | |
895 | * @xas: XArray operation state. | |
896 | * @mark: Mark number. | |
897 | * | |
898 | * Clears the specified mark on this entry, and walks back to the head | |
899 | * attempting to clear it on all the ancestor entries. Does nothing if | |
900 | * @xas has not been walked to an entry, or is in an error state. | |
901 | */ | |
902 | void xas_clear_mark(const struct xa_state *xas, xa_mark_t mark) | |
903 | { | |
904 | struct xa_node *node = xas->xa_node; | |
905 | unsigned int offset = xas->xa_offset; | |
906 | ||
907 | if (xas_invalid(xas)) | |
908 | return; | |
909 | ||
910 | while (node) { | |
911 | if (!node_clear_mark(node, offset, mark)) | |
912 | return; | |
913 | if (node_any_mark(node, mark)) | |
914 | return; | |
915 | ||
916 | offset = node->offset; | |
917 | node = xa_parent_locked(xas->xa, node); | |
918 | } | |
919 | ||
920 | if (xa_marked(xas->xa, mark)) | |
921 | xa_mark_clear(xas->xa, mark); | |
922 | } | |
923 | EXPORT_SYMBOL_GPL(xas_clear_mark); | |
924 | ||
58d6ea30 MW |
925 | /** |
926 | * xas_init_marks() - Initialise all marks for the entry | |
927 | * @xas: Array operations state. | |
928 | * | |
929 | * Initialise all marks for the entry specified by @xas. If we're tracking | |
930 | * free entries with a mark, we need to set it on all entries. All other | |
931 | * marks are cleared. | |
932 | * | |
933 | * This implementation is not as efficient as it could be; we may walk | |
934 | * up the tree multiple times. | |
935 | */ | |
936 | void xas_init_marks(const struct xa_state *xas) | |
937 | { | |
938 | xa_mark_t mark = 0; | |
939 | ||
940 | for (;;) { | |
371c752d MW |
941 | if (xa_track_free(xas->xa) && mark == XA_FREE_MARK) |
942 | xas_set_mark(xas, mark); | |
943 | else | |
944 | xas_clear_mark(xas, mark); | |
58d6ea30 MW |
945 | if (mark == XA_MARK_MAX) |
946 | break; | |
947 | mark_inc(mark); | |
948 | } | |
949 | } | |
950 | EXPORT_SYMBOL_GPL(xas_init_marks); | |
951 | ||
8fc75643 MWO |
952 | #ifdef CONFIG_XARRAY_MULTI |
953 | static unsigned int node_get_marks(struct xa_node *node, unsigned int offset) | |
954 | { | |
955 | unsigned int marks = 0; | |
956 | xa_mark_t mark = XA_MARK_0; | |
957 | ||
958 | for (;;) { | |
959 | if (node_get_mark(node, offset, mark)) | |
960 | marks |= 1 << (__force unsigned int)mark; | |
961 | if (mark == XA_MARK_MAX) | |
962 | break; | |
963 | mark_inc(mark); | |
964 | } | |
965 | ||
966 | return marks; | |
967 | } | |
968 | ||
969 | static void node_set_marks(struct xa_node *node, unsigned int offset, | |
970 | struct xa_node *child, unsigned int marks) | |
971 | { | |
972 | xa_mark_t mark = XA_MARK_0; | |
973 | ||
974 | for (;;) { | |
975 | if (marks & (1 << (__force unsigned int)mark)) { | |
976 | node_set_mark(node, offset, mark); | |
977 | if (child) | |
978 | node_mark_all(child, mark); | |
979 | } | |
980 | if (mark == XA_MARK_MAX) | |
981 | break; | |
982 | mark_inc(mark); | |
983 | } | |
984 | } | |
985 | ||
986 | /** | |
987 | * xas_split_alloc() - Allocate memory for splitting an entry. | |
988 | * @xas: XArray operation state. | |
989 | * @entry: New entry which will be stored in the array. | |
990 | * @order: New entry order. | |
991 | * @gfp: Memory allocation flags. | |
992 | * | |
993 | * This function should be called before calling xas_split(). | |
994 | * If necessary, it will allocate new nodes (and fill them with @entry) | |
995 | * to prepare for the upcoming split of an entry of @order size into | |
996 | * entries of the order stored in the @xas. | |
997 | * | |
998 | * Context: May sleep if @gfp flags permit. | |
999 | */ | |
1000 | void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order, | |
1001 | gfp_t gfp) | |
1002 | { | |
1003 | unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; | |
1004 | unsigned int mask = xas->xa_sibs; | |
1005 | ||
1006 | /* XXX: no support for splitting really large entries yet */ | |
1007 | if (WARN_ON(xas->xa_shift + 2 * XA_CHUNK_SHIFT < order)) | |
1008 | goto nomem; | |
1009 | if (xas->xa_shift + XA_CHUNK_SHIFT > order) | |
1010 | return; | |
1011 | ||
1012 | do { | |
1013 | unsigned int i; | |
1014 | void *sibling; | |
1015 | struct xa_node *node; | |
1016 | ||
1017 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp); | |
1018 | if (!node) | |
1019 | goto nomem; | |
1020 | node->array = xas->xa; | |
1021 | for (i = 0; i < XA_CHUNK_SIZE; i++) { | |
1022 | if ((i & mask) == 0) { | |
1023 | RCU_INIT_POINTER(node->slots[i], entry); | |
1024 | sibling = xa_mk_sibling(0); | |
1025 | } else { | |
1026 | RCU_INIT_POINTER(node->slots[i], sibling); | |
1027 | } | |
1028 | } | |
1029 | RCU_INIT_POINTER(node->parent, xas->xa_alloc); | |
1030 | xas->xa_alloc = node; | |
1031 | } while (sibs-- > 0); | |
1032 | ||
1033 | return; | |
1034 | nomem: | |
1035 | xas_destroy(xas); | |
1036 | xas_set_err(xas, -ENOMEM); | |
1037 | } | |
1038 | EXPORT_SYMBOL_GPL(xas_split_alloc); | |
1039 | ||
1040 | /** | |
1041 | * xas_split() - Split a multi-index entry into smaller entries. | |
1042 | * @xas: XArray operation state. | |
1043 | * @entry: New entry to store in the array. | |
1044 | * @order: New entry order. | |
1045 | * | |
1046 | * The value in the entry is copied to all the replacement entries. | |
1047 | * | |
1048 | * Context: Any context. The caller should hold the xa_lock. | |
1049 | */ | |
1050 | void xas_split(struct xa_state *xas, void *entry, unsigned int order) | |
1051 | { | |
1052 | unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; | |
1053 | unsigned int offset, marks; | |
1054 | struct xa_node *node; | |
1055 | void *curr = xas_load(xas); | |
1056 | int values = 0; | |
1057 | ||
1058 | node = xas->xa_node; | |
1059 | if (xas_top(node)) | |
1060 | return; | |
1061 | ||
1062 | marks = node_get_marks(node, xas->xa_offset); | |
1063 | ||
1064 | offset = xas->xa_offset + sibs; | |
1065 | do { | |
1066 | if (xas->xa_shift < node->shift) { | |
1067 | struct xa_node *child = xas->xa_alloc; | |
1068 | ||
1069 | xas->xa_alloc = rcu_dereference_raw(child->parent); | |
1070 | child->shift = node->shift - XA_CHUNK_SHIFT; | |
1071 | child->offset = offset; | |
1072 | child->count = XA_CHUNK_SIZE; | |
1073 | child->nr_values = xa_is_value(entry) ? | |
1074 | XA_CHUNK_SIZE : 0; | |
1075 | RCU_INIT_POINTER(child->parent, node); | |
1076 | node_set_marks(node, offset, child, marks); | |
1077 | rcu_assign_pointer(node->slots[offset], | |
1078 | xa_mk_node(child)); | |
1079 | if (xa_is_value(curr)) | |
1080 | values--; | |
1081 | } else { | |
1082 | unsigned int canon = offset - xas->xa_sibs; | |
1083 | ||
1084 | node_set_marks(node, canon, NULL, marks); | |
1085 | rcu_assign_pointer(node->slots[canon], entry); | |
1086 | while (offset > canon) | |
1087 | rcu_assign_pointer(node->slots[offset--], | |
1088 | xa_mk_sibling(canon)); | |
1089 | values += (xa_is_value(entry) - xa_is_value(curr)) * | |
1090 | (xas->xa_sibs + 1); | |
1091 | } | |
1092 | } while (offset-- > xas->xa_offset); | |
1093 | ||
1094 | node->nr_values += values; | |
1095 | } | |
1096 | EXPORT_SYMBOL_GPL(xas_split); | |
1097 | #endif | |
1098 | ||
b803b428 MW |
1099 | /** |
1100 | * xas_pause() - Pause a walk to drop a lock. | |
1101 | * @xas: XArray operation state. | |
1102 | * | |
1103 | * Some users need to pause a walk and drop the lock they're holding in | |
1104 | * order to yield to a higher priority thread or carry out an operation | |
1105 | * on an entry. Those users should call this function before they drop | |
1106 | * the lock. It resets the @xas to be suitable for the next iteration | |
1107 | * of the loop after the user has reacquired the lock. If most entries | |
1108 | * found during a walk require you to call xas_pause(), the xa_for_each() | |
1109 | * iterator may be more appropriate. | |
1110 | * | |
1111 | * Note that xas_pause() only works for forward iteration. If a user needs | |
1112 | * to pause a reverse iteration, we will need a xas_pause_rev(). | |
1113 | */ | |
1114 | void xas_pause(struct xa_state *xas) | |
1115 | { | |
1116 | struct xa_node *node = xas->xa_node; | |
1117 | ||
1118 | if (xas_invalid(xas)) | |
1119 | return; | |
1120 | ||
82a22311 | 1121 | xas->xa_node = XAS_RESTART; |
b803b428 | 1122 | if (node) { |
c36d451a | 1123 | unsigned long offset = xas->xa_offset; |
b803b428 MW |
1124 | while (++offset < XA_CHUNK_SIZE) { |
1125 | if (!xa_is_sibling(xa_entry(xas->xa, node, offset))) | |
1126 | break; | |
1127 | } | |
1128 | xas->xa_index += (offset - xas->xa_offset) << node->shift; | |
82a22311 MWO |
1129 | if (xas->xa_index == 0) |
1130 | xas->xa_node = XAS_BOUNDS; | |
b803b428 MW |
1131 | } else { |
1132 | xas->xa_index++; | |
1133 | } | |
b803b428 MW |
1134 | } |
1135 | EXPORT_SYMBOL_GPL(xas_pause); | |
1136 | ||
64d3e9a9 MW |
1137 | /* |
1138 | * __xas_prev() - Find the previous entry in the XArray. | |
1139 | * @xas: XArray operation state. | |
1140 | * | |
1141 | * Helper function for xas_prev() which handles all the complex cases | |
1142 | * out of line. | |
1143 | */ | |
1144 | void *__xas_prev(struct xa_state *xas) | |
1145 | { | |
1146 | void *entry; | |
1147 | ||
1148 | if (!xas_frozen(xas->xa_node)) | |
1149 | xas->xa_index--; | |
91abab83 MWO |
1150 | if (!xas->xa_node) |
1151 | return set_bounds(xas); | |
64d3e9a9 MW |
1152 | if (xas_not_node(xas->xa_node)) |
1153 | return xas_load(xas); | |
1154 | ||
1155 | if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) | |
1156 | xas->xa_offset--; | |
1157 | ||
1158 | while (xas->xa_offset == 255) { | |
1159 | xas->xa_offset = xas->xa_node->offset - 1; | |
1160 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1161 | if (!xas->xa_node) | |
1162 | return set_bounds(xas); | |
1163 | } | |
1164 | ||
1165 | for (;;) { | |
1166 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1167 | if (!xa_is_node(entry)) | |
1168 | return entry; | |
1169 | ||
1170 | xas->xa_node = xa_to_node(entry); | |
1171 | xas_set_offset(xas); | |
1172 | } | |
1173 | } | |
1174 | EXPORT_SYMBOL_GPL(__xas_prev); | |
1175 | ||
1176 | /* | |
1177 | * __xas_next() - Find the next entry in the XArray. | |
1178 | * @xas: XArray operation state. | |
1179 | * | |
1180 | * Helper function for xas_next() which handles all the complex cases | |
1181 | * out of line. | |
1182 | */ | |
1183 | void *__xas_next(struct xa_state *xas) | |
1184 | { | |
1185 | void *entry; | |
1186 | ||
1187 | if (!xas_frozen(xas->xa_node)) | |
1188 | xas->xa_index++; | |
91abab83 MWO |
1189 | if (!xas->xa_node) |
1190 | return set_bounds(xas); | |
64d3e9a9 MW |
1191 | if (xas_not_node(xas->xa_node)) |
1192 | return xas_load(xas); | |
1193 | ||
1194 | if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) | |
1195 | xas->xa_offset++; | |
1196 | ||
1197 | while (xas->xa_offset == XA_CHUNK_SIZE) { | |
1198 | xas->xa_offset = xas->xa_node->offset + 1; | |
1199 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1200 | if (!xas->xa_node) | |
1201 | return set_bounds(xas); | |
1202 | } | |
1203 | ||
1204 | for (;;) { | |
1205 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1206 | if (!xa_is_node(entry)) | |
1207 | return entry; | |
1208 | ||
1209 | xas->xa_node = xa_to_node(entry); | |
1210 | xas_set_offset(xas); | |
1211 | } | |
1212 | } | |
1213 | EXPORT_SYMBOL_GPL(__xas_next); | |
1214 | ||
b803b428 MW |
1215 | /** |
1216 | * xas_find() - Find the next present entry in the XArray. | |
1217 | * @xas: XArray operation state. | |
1218 | * @max: Highest index to return. | |
1219 | * | |
1220 | * If the @xas has not yet been walked to an entry, return the entry | |
1221 | * which has an index >= xas.xa_index. If it has been walked, the entry | |
1222 | * currently being pointed at has been processed, and so we move to the | |
1223 | * next entry. | |
1224 | * | |
1225 | * If no entry is found and the array is smaller than @max, the iterator | |
1226 | * is set to the smallest index not yet in the array. This allows @xas | |
1227 | * to be immediately passed to xas_store(). | |
1228 | * | |
1229 | * Return: The entry, if found, otherwise %NULL. | |
1230 | */ | |
1231 | void *xas_find(struct xa_state *xas, unsigned long max) | |
1232 | { | |
1233 | void *entry; | |
1234 | ||
82a22311 | 1235 | if (xas_error(xas) || xas->xa_node == XAS_BOUNDS) |
b803b428 | 1236 | return NULL; |
c44aa5e8 MWO |
1237 | if (xas->xa_index > max) |
1238 | return set_bounds(xas); | |
b803b428 MW |
1239 | |
1240 | if (!xas->xa_node) { | |
1241 | xas->xa_index = 1; | |
1242 | return set_bounds(xas); | |
82a22311 | 1243 | } else if (xas->xa_node == XAS_RESTART) { |
b803b428 MW |
1244 | entry = xas_load(xas); |
1245 | if (entry || xas_not_node(xas->xa_node)) | |
1246 | return entry; | |
1247 | } else if (!xas->xa_node->shift && | |
1248 | xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK)) { | |
1249 | xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1; | |
1250 | } | |
1251 | ||
1252 | xas_advance(xas); | |
1253 | ||
1254 | while (xas->xa_node && (xas->xa_index <= max)) { | |
1255 | if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { | |
1256 | xas->xa_offset = xas->xa_node->offset + 1; | |
1257 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1258 | continue; | |
1259 | } | |
1260 | ||
1261 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1262 | if (xa_is_node(entry)) { | |
1263 | xas->xa_node = xa_to_node(entry); | |
1264 | xas->xa_offset = 0; | |
1265 | continue; | |
1266 | } | |
1267 | if (entry && !xa_is_sibling(entry)) | |
1268 | return entry; | |
1269 | ||
1270 | xas_advance(xas); | |
1271 | } | |
1272 | ||
1273 | if (!xas->xa_node) | |
1274 | xas->xa_node = XAS_BOUNDS; | |
1275 | return NULL; | |
1276 | } | |
1277 | EXPORT_SYMBOL_GPL(xas_find); | |
1278 | ||
1279 | /** | |
1280 | * xas_find_marked() - Find the next marked entry in the XArray. | |
1281 | * @xas: XArray operation state. | |
1282 | * @max: Highest index to return. | |
1283 | * @mark: Mark number to search for. | |
1284 | * | |
1285 | * If the @xas has not yet been walked to an entry, return the marked entry | |
1286 | * which has an index >= xas.xa_index. If it has been walked, the entry | |
1287 | * currently being pointed at has been processed, and so we return the | |
1288 | * first marked entry with an index > xas.xa_index. | |
1289 | * | |
1290 | * If no marked entry is found and the array is smaller than @max, @xas is | |
1291 | * set to the bounds state and xas->xa_index is set to the smallest index | |
1292 | * not yet in the array. This allows @xas to be immediately passed to | |
1293 | * xas_store(). | |
1294 | * | |
1295 | * If no entry is found before @max is reached, @xas is set to the restart | |
1296 | * state. | |
1297 | * | |
1298 | * Return: The entry, if found, otherwise %NULL. | |
1299 | */ | |
1300 | void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark) | |
1301 | { | |
1302 | bool advance = true; | |
1303 | unsigned int offset; | |
1304 | void *entry; | |
1305 | ||
1306 | if (xas_error(xas)) | |
1307 | return NULL; | |
c44aa5e8 MWO |
1308 | if (xas->xa_index > max) |
1309 | goto max; | |
b803b428 MW |
1310 | |
1311 | if (!xas->xa_node) { | |
1312 | xas->xa_index = 1; | |
1313 | goto out; | |
1314 | } else if (xas_top(xas->xa_node)) { | |
1315 | advance = false; | |
1316 | entry = xa_head(xas->xa); | |
1317 | xas->xa_node = NULL; | |
1318 | if (xas->xa_index > max_index(entry)) | |
48483614 | 1319 | goto out; |
b803b428 MW |
1320 | if (!xa_is_node(entry)) { |
1321 | if (xa_marked(xas->xa, mark)) | |
1322 | return entry; | |
1323 | xas->xa_index = 1; | |
1324 | goto out; | |
1325 | } | |
1326 | xas->xa_node = xa_to_node(entry); | |
1327 | xas->xa_offset = xas->xa_index >> xas->xa_node->shift; | |
1328 | } | |
1329 | ||
1330 | while (xas->xa_index <= max) { | |
1331 | if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { | |
1332 | xas->xa_offset = xas->xa_node->offset + 1; | |
1333 | xas->xa_node = xa_parent(xas->xa, xas->xa_node); | |
1334 | if (!xas->xa_node) | |
1335 | break; | |
1336 | advance = false; | |
1337 | continue; | |
1338 | } | |
1339 | ||
1340 | if (!advance) { | |
1341 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
1342 | if (xa_is_sibling(entry)) { | |
1343 | xas->xa_offset = xa_to_sibling(entry); | |
1344 | xas_move_index(xas, xas->xa_offset); | |
1345 | } | |
1346 | } | |
1347 | ||
1348 | offset = xas_find_chunk(xas, advance, mark); | |
1349 | if (offset > xas->xa_offset) { | |
1350 | advance = false; | |
1351 | xas_move_index(xas, offset); | |
1352 | /* Mind the wrap */ | |
1353 | if ((xas->xa_index - 1) >= max) | |
1354 | goto max; | |
1355 | xas->xa_offset = offset; | |
1356 | if (offset == XA_CHUNK_SIZE) | |
1357 | continue; | |
1358 | } | |
1359 | ||
1360 | entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); | |
7e934cf5 MWO |
1361 | if (!entry && !(xa_track_free(xas->xa) && mark == XA_FREE_MARK)) |
1362 | continue; | |
b803b428 MW |
1363 | if (!xa_is_node(entry)) |
1364 | return entry; | |
1365 | xas->xa_node = xa_to_node(entry); | |
1366 | xas_set_offset(xas); | |
1367 | } | |
1368 | ||
1369 | out: | |
48483614 | 1370 | if (xas->xa_index > max) |
b803b428 | 1371 | goto max; |
48483614 | 1372 | return set_bounds(xas); |
b803b428 MW |
1373 | max: |
1374 | xas->xa_node = XAS_RESTART; | |
1375 | return NULL; | |
1376 | } | |
1377 | EXPORT_SYMBOL_GPL(xas_find_marked); | |
1378 | ||
4e99d4e9 MW |
1379 | /** |
1380 | * xas_find_conflict() - Find the next present entry in a range. | |
1381 | * @xas: XArray operation state. | |
1382 | * | |
1383 | * The @xas describes both a range and a position within that range. | |
1384 | * | |
1385 | * Context: Any context. Expects xa_lock to be held. | |
1386 | * Return: The next entry in the range covered by @xas or %NULL. | |
1387 | */ | |
1388 | void *xas_find_conflict(struct xa_state *xas) | |
1389 | { | |
1390 | void *curr; | |
1391 | ||
1392 | if (xas_error(xas)) | |
1393 | return NULL; | |
1394 | ||
1395 | if (!xas->xa_node) | |
1396 | return NULL; | |
1397 | ||
1398 | if (xas_top(xas->xa_node)) { | |
1399 | curr = xas_start(xas); | |
1400 | if (!curr) | |
1401 | return NULL; | |
1402 | while (xa_is_node(curr)) { | |
1403 | struct xa_node *node = xa_to_node(curr); | |
1404 | curr = xas_descend(xas, node); | |
1405 | } | |
1406 | if (curr) | |
1407 | return curr; | |
1408 | } | |
1409 | ||
1410 | if (xas->xa_node->shift > xas->xa_shift) | |
1411 | return NULL; | |
1412 | ||
1413 | for (;;) { | |
1414 | if (xas->xa_node->shift == xas->xa_shift) { | |
1415 | if ((xas->xa_offset & xas->xa_sibs) == xas->xa_sibs) | |
1416 | break; | |
1417 | } else if (xas->xa_offset == XA_CHUNK_MASK) { | |
1418 | xas->xa_offset = xas->xa_node->offset; | |
1419 | xas->xa_node = xa_parent_locked(xas->xa, xas->xa_node); | |
1420 | if (!xas->xa_node) | |
1421 | break; | |
1422 | continue; | |
1423 | } | |
1424 | curr = xa_entry_locked(xas->xa, xas->xa_node, ++xas->xa_offset); | |
1425 | if (xa_is_sibling(curr)) | |
1426 | continue; | |
1427 | while (xa_is_node(curr)) { | |
1428 | xas->xa_node = xa_to_node(curr); | |
1429 | xas->xa_offset = 0; | |
1430 | curr = xa_entry_locked(xas->xa, xas->xa_node, 0); | |
1431 | } | |
1432 | if (curr) | |
1433 | return curr; | |
1434 | } | |
1435 | xas->xa_offset -= xas->xa_sibs; | |
1436 | return NULL; | |
1437 | } | |
1438 | EXPORT_SYMBOL_GPL(xas_find_conflict); | |
1439 | ||
ad3d6c72 MW |
1440 | /** |
1441 | * xa_load() - Load an entry from an XArray. | |
1442 | * @xa: XArray. | |
1443 | * @index: index into array. | |
1444 | * | |
1445 | * Context: Any context. Takes and releases the RCU lock. | |
1446 | * Return: The entry at @index in @xa. | |
1447 | */ | |
1448 | void *xa_load(struct xarray *xa, unsigned long index) | |
1449 | { | |
1450 | XA_STATE(xas, xa, index); | |
1451 | void *entry; | |
1452 | ||
1453 | rcu_read_lock(); | |
1454 | do { | |
1455 | entry = xas_load(&xas); | |
9f14d4f1 MW |
1456 | if (xa_is_zero(entry)) |
1457 | entry = NULL; | |
ad3d6c72 MW |
1458 | } while (xas_retry(&xas, entry)); |
1459 | rcu_read_unlock(); | |
1460 | ||
1461 | return entry; | |
1462 | } | |
1463 | EXPORT_SYMBOL(xa_load); | |
1464 | ||
58d6ea30 MW |
1465 | static void *xas_result(struct xa_state *xas, void *curr) |
1466 | { | |
9f14d4f1 MW |
1467 | if (xa_is_zero(curr)) |
1468 | return NULL; | |
58d6ea30 MW |
1469 | if (xas_error(xas)) |
1470 | curr = xas->xa_node; | |
1471 | return curr; | |
1472 | } | |
1473 | ||
1474 | /** | |
1475 | * __xa_erase() - Erase this entry from the XArray while locked. | |
1476 | * @xa: XArray. | |
1477 | * @index: Index into array. | |
1478 | * | |
809ab937 MW |
1479 | * After this function returns, loading from @index will return %NULL. |
1480 | * If the index is part of a multi-index entry, all indices will be erased | |
1481 | * and none of the entries will be part of a multi-index entry. | |
58d6ea30 | 1482 | * |
809ab937 MW |
1483 | * Context: Any context. Expects xa_lock to be held on entry. |
1484 | * Return: The entry which used to be at this index. | |
58d6ea30 MW |
1485 | */ |
1486 | void *__xa_erase(struct xarray *xa, unsigned long index) | |
1487 | { | |
1488 | XA_STATE(xas, xa, index); | |
1489 | return xas_result(&xas, xas_store(&xas, NULL)); | |
1490 | } | |
9ee5a3b7 | 1491 | EXPORT_SYMBOL(__xa_erase); |
58d6ea30 | 1492 | |
9c16bb88 MW |
1493 | /** |
1494 | * xa_erase() - Erase this entry from the XArray. | |
1495 | * @xa: XArray. | |
1496 | * @index: Index of entry. | |
1497 | * | |
809ab937 MW |
1498 | * After this function returns, loading from @index will return %NULL. |
1499 | * If the index is part of a multi-index entry, all indices will be erased | |
1500 | * and none of the entries will be part of a multi-index entry. | |
9c16bb88 MW |
1501 | * |
1502 | * Context: Any context. Takes and releases the xa_lock. | |
1503 | * Return: The entry which used to be at this index. | |
1504 | */ | |
1505 | void *xa_erase(struct xarray *xa, unsigned long index) | |
1506 | { | |
1507 | void *entry; | |
1508 | ||
1509 | xa_lock(xa); | |
1510 | entry = __xa_erase(xa, index); | |
1511 | xa_unlock(xa); | |
1512 | ||
1513 | return entry; | |
1514 | } | |
1515 | EXPORT_SYMBOL(xa_erase); | |
1516 | ||
58d6ea30 | 1517 | /** |
611f3186 | 1518 | * __xa_store() - Store this entry in the XArray. |
58d6ea30 MW |
1519 | * @xa: XArray. |
1520 | * @index: Index into array. | |
1521 | * @entry: New entry. | |
1522 | * @gfp: Memory allocation flags. | |
1523 | * | |
611f3186 MW |
1524 | * You must already be holding the xa_lock when calling this function. |
1525 | * It will drop the lock if needed to allocate memory, and then reacquire | |
1526 | * it afterwards. | |
58d6ea30 | 1527 | * |
611f3186 MW |
1528 | * Context: Any context. Expects xa_lock to be held on entry. May |
1529 | * release and reacquire xa_lock if @gfp flags permit. | |
1530 | * Return: The old entry at this index or xa_err() if an error happened. | |
58d6ea30 | 1531 | */ |
611f3186 | 1532 | void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) |
58d6ea30 MW |
1533 | { |
1534 | XA_STATE(xas, xa, index); | |
1535 | void *curr; | |
1536 | ||
76b4e529 | 1537 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
58d6ea30 | 1538 | return XA_ERROR(-EINVAL); |
d9c48043 MW |
1539 | if (xa_track_free(xa) && !entry) |
1540 | entry = XA_ZERO_ENTRY; | |
58d6ea30 MW |
1541 | |
1542 | do { | |
58d6ea30 | 1543 | curr = xas_store(&xas, entry); |
d9c48043 | 1544 | if (xa_track_free(xa)) |
371c752d | 1545 | xas_clear_mark(&xas, XA_FREE_MARK); |
611f3186 | 1546 | } while (__xas_nomem(&xas, gfp)); |
58d6ea30 MW |
1547 | |
1548 | return xas_result(&xas, curr); | |
1549 | } | |
611f3186 | 1550 | EXPORT_SYMBOL(__xa_store); |
58d6ea30 MW |
1551 | |
1552 | /** | |
611f3186 | 1553 | * xa_store() - Store this entry in the XArray. |
58d6ea30 MW |
1554 | * @xa: XArray. |
1555 | * @index: Index into array. | |
1556 | * @entry: New entry. | |
1557 | * @gfp: Memory allocation flags. | |
1558 | * | |
611f3186 | 1559 | * After this function returns, loads from this index will return @entry. |
8fc75643 | 1560 | * Storing into an existing multi-index entry updates the entry of every index. |
611f3186 | 1561 | * The marks associated with @index are unaffected unless @entry is %NULL. |
58d6ea30 | 1562 | * |
611f3186 MW |
1563 | * Context: Any context. Takes and releases the xa_lock. |
1564 | * May sleep if the @gfp flags permit. | |
1565 | * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry | |
1566 | * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation | |
1567 | * failed. | |
58d6ea30 | 1568 | */ |
611f3186 | 1569 | void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) |
58d6ea30 | 1570 | { |
58d6ea30 MW |
1571 | void *curr; |
1572 | ||
611f3186 MW |
1573 | xa_lock(xa); |
1574 | curr = __xa_store(xa, index, entry, gfp); | |
1575 | xa_unlock(xa); | |
58d6ea30 | 1576 | |
611f3186 | 1577 | return curr; |
58d6ea30 | 1578 | } |
611f3186 | 1579 | EXPORT_SYMBOL(xa_store); |
58d6ea30 | 1580 | |
41aec91f MW |
1581 | /** |
1582 | * __xa_cmpxchg() - Store this entry in the XArray. | |
1583 | * @xa: XArray. | |
1584 | * @index: Index into array. | |
1585 | * @old: Old value to test against. | |
1586 | * @entry: New entry. | |
1587 | * @gfp: Memory allocation flags. | |
1588 | * | |
1589 | * You must already be holding the xa_lock when calling this function. | |
1590 | * It will drop the lock if needed to allocate memory, and then reacquire | |
1591 | * it afterwards. | |
1592 | * | |
1593 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1594 | * release and reacquire xa_lock if @gfp flags permit. | |
1595 | * Return: The old entry at this index or xa_err() if an error happened. | |
1596 | */ | |
1597 | void *__xa_cmpxchg(struct xarray *xa, unsigned long index, | |
1598 | void *old, void *entry, gfp_t gfp) | |
1599 | { | |
1600 | XA_STATE(xas, xa, index); | |
1601 | void *curr; | |
1602 | ||
76b4e529 | 1603 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
41aec91f MW |
1604 | return XA_ERROR(-EINVAL); |
1605 | ||
1606 | do { | |
1607 | curr = xas_load(&xas); | |
371c752d | 1608 | if (curr == old) { |
41aec91f | 1609 | xas_store(&xas, entry); |
b38f6c50 | 1610 | if (xa_track_free(xa) && entry && !curr) |
371c752d MW |
1611 | xas_clear_mark(&xas, XA_FREE_MARK); |
1612 | } | |
41aec91f MW |
1613 | } while (__xas_nomem(&xas, gfp)); |
1614 | ||
1615 | return xas_result(&xas, curr); | |
1616 | } | |
1617 | EXPORT_SYMBOL(__xa_cmpxchg); | |
1618 | ||
b0606fed MW |
1619 | /** |
1620 | * __xa_insert() - Store this entry in the XArray if no entry is present. | |
1621 | * @xa: XArray. | |
1622 | * @index: Index into array. | |
1623 | * @entry: New entry. | |
1624 | * @gfp: Memory allocation flags. | |
1625 | * | |
1626 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) | |
1627 | * if no entry is present. Inserting will fail if a reserved entry is | |
1628 | * present, even though loading from this index will return NULL. | |
1629 | * | |
1630 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1631 | * release and reacquire xa_lock if @gfp flags permit. | |
fd9dc93e | 1632 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
b0606fed MW |
1633 | * -ENOMEM if memory could not be allocated. |
1634 | */ | |
1635 | int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) | |
1636 | { | |
1637 | XA_STATE(xas, xa, index); | |
1638 | void *curr; | |
1639 | ||
1640 | if (WARN_ON_ONCE(xa_is_advanced(entry))) | |
1641 | return -EINVAL; | |
1642 | if (!entry) | |
1643 | entry = XA_ZERO_ENTRY; | |
1644 | ||
1645 | do { | |
1646 | curr = xas_load(&xas); | |
1647 | if (!curr) { | |
1648 | xas_store(&xas, entry); | |
1649 | if (xa_track_free(xa)) | |
1650 | xas_clear_mark(&xas, XA_FREE_MARK); | |
1651 | } else { | |
fd9dc93e | 1652 | xas_set_err(&xas, -EBUSY); |
b0606fed MW |
1653 | } |
1654 | } while (__xas_nomem(&xas, gfp)); | |
1655 | ||
1656 | return xas_error(&xas); | |
1657 | } | |
1658 | EXPORT_SYMBOL(__xa_insert); | |
1659 | ||
0e9446c3 MW |
1660 | #ifdef CONFIG_XARRAY_MULTI |
1661 | static void xas_set_range(struct xa_state *xas, unsigned long first, | |
1662 | unsigned long last) | |
1663 | { | |
1664 | unsigned int shift = 0; | |
1665 | unsigned long sibs = last - first; | |
1666 | unsigned int offset = XA_CHUNK_MASK; | |
1667 | ||
1668 | xas_set(xas, first); | |
1669 | ||
1670 | while ((first & XA_CHUNK_MASK) == 0) { | |
1671 | if (sibs < XA_CHUNK_MASK) | |
1672 | break; | |
1673 | if ((sibs == XA_CHUNK_MASK) && (offset < XA_CHUNK_MASK)) | |
1674 | break; | |
1675 | shift += XA_CHUNK_SHIFT; | |
1676 | if (offset == XA_CHUNK_MASK) | |
1677 | offset = sibs & XA_CHUNK_MASK; | |
1678 | sibs >>= XA_CHUNK_SHIFT; | |
1679 | first >>= XA_CHUNK_SHIFT; | |
1680 | } | |
1681 | ||
1682 | offset = first & XA_CHUNK_MASK; | |
1683 | if (offset + sibs > XA_CHUNK_MASK) | |
1684 | sibs = XA_CHUNK_MASK - offset; | |
1685 | if ((((first + sibs + 1) << shift) - 1) > last) | |
1686 | sibs -= 1; | |
1687 | ||
1688 | xas->xa_shift = shift; | |
1689 | xas->xa_sibs = sibs; | |
1690 | } | |
1691 | ||
1692 | /** | |
1693 | * xa_store_range() - Store this entry at a range of indices in the XArray. | |
1694 | * @xa: XArray. | |
1695 | * @first: First index to affect. | |
1696 | * @last: Last index to affect. | |
1697 | * @entry: New entry. | |
1698 | * @gfp: Memory allocation flags. | |
1699 | * | |
1700 | * After this function returns, loads from any index between @first and @last, | |
1701 | * inclusive will return @entry. | |
8fc75643 | 1702 | * Storing into an existing multi-index entry updates the entry of every index. |
0e9446c3 MW |
1703 | * The marks associated with @index are unaffected unless @entry is %NULL. |
1704 | * | |
1705 | * Context: Process context. Takes and releases the xa_lock. May sleep | |
1706 | * if the @gfp flags permit. | |
1707 | * Return: %NULL on success, xa_err(-EINVAL) if @entry cannot be stored in | |
1708 | * an XArray, or xa_err(-ENOMEM) if memory allocation failed. | |
1709 | */ | |
1710 | void *xa_store_range(struct xarray *xa, unsigned long first, | |
1711 | unsigned long last, void *entry, gfp_t gfp) | |
1712 | { | |
1713 | XA_STATE(xas, xa, 0); | |
1714 | ||
1715 | if (WARN_ON_ONCE(xa_is_internal(entry))) | |
1716 | return XA_ERROR(-EINVAL); | |
1717 | if (last < first) | |
1718 | return XA_ERROR(-EINVAL); | |
1719 | ||
1720 | do { | |
1721 | xas_lock(&xas); | |
1722 | if (entry) { | |
44a4a66b MW |
1723 | unsigned int order = BITS_PER_LONG; |
1724 | if (last + 1) | |
1725 | order = __ffs(last + 1); | |
0e9446c3 | 1726 | xas_set_order(&xas, last, order); |
76b4e529 | 1727 | xas_create(&xas, true); |
0e9446c3 MW |
1728 | if (xas_error(&xas)) |
1729 | goto unlock; | |
1730 | } | |
1731 | do { | |
1732 | xas_set_range(&xas, first, last); | |
1733 | xas_store(&xas, entry); | |
1734 | if (xas_error(&xas)) | |
1735 | goto unlock; | |
1736 | first += xas_size(&xas); | |
1737 | } while (first <= last); | |
1738 | unlock: | |
1739 | xas_unlock(&xas); | |
1740 | } while (xas_nomem(&xas, gfp)); | |
1741 | ||
1742 | return xas_result(&xas, NULL); | |
1743 | } | |
1744 | EXPORT_SYMBOL(xa_store_range); | |
57417ceb MWO |
1745 | |
1746 | /** | |
1747 | * xa_get_order() - Get the order of an entry. | |
1748 | * @xa: XArray. | |
1749 | * @index: Index of the entry. | |
1750 | * | |
1751 | * Return: A number between 0 and 63 indicating the order of the entry. | |
1752 | */ | |
1753 | int xa_get_order(struct xarray *xa, unsigned long index) | |
1754 | { | |
1755 | XA_STATE(xas, xa, index); | |
1756 | void *entry; | |
1757 | int order = 0; | |
1758 | ||
1759 | rcu_read_lock(); | |
1760 | entry = xas_load(&xas); | |
1761 | ||
1762 | if (!entry) | |
1763 | goto unlock; | |
1764 | ||
1765 | if (!xas.xa_node) | |
1766 | goto unlock; | |
1767 | ||
1768 | for (;;) { | |
1769 | unsigned int slot = xas.xa_offset + (1 << order); | |
1770 | ||
1771 | if (slot >= XA_CHUNK_SIZE) | |
1772 | break; | |
1773 | if (!xa_is_sibling(xas.xa_node->slots[slot])) | |
1774 | break; | |
1775 | order++; | |
1776 | } | |
1777 | ||
1778 | order += xas.xa_node->shift; | |
1779 | unlock: | |
1780 | rcu_read_unlock(); | |
1781 | ||
1782 | return order; | |
1783 | } | |
1784 | EXPORT_SYMBOL(xa_get_order); | |
0e9446c3 MW |
1785 | #endif /* CONFIG_XARRAY_MULTI */ |
1786 | ||
371c752d MW |
1787 | /** |
1788 | * __xa_alloc() - Find somewhere to store this entry in the XArray. | |
1789 | * @xa: XArray. | |
1790 | * @id: Pointer to ID. | |
a3e4d3f9 | 1791 | * @limit: Range for allocated ID. |
371c752d MW |
1792 | * @entry: New entry. |
1793 | * @gfp: Memory allocation flags. | |
1794 | * | |
a3e4d3f9 MW |
1795 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
1796 | * stores the index into the @id pointer, then stores the entry at | |
1797 | * that index. A concurrent lookup will not see an uninitialised @id. | |
371c752d MW |
1798 | * |
1799 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1800 | * release and reacquire xa_lock if @gfp flags permit. | |
a3e4d3f9 MW |
1801 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
1802 | * -EBUSY if there are no free entries in @limit. | |
371c752d | 1803 | */ |
a3e4d3f9 MW |
1804 | int __xa_alloc(struct xarray *xa, u32 *id, void *entry, |
1805 | struct xa_limit limit, gfp_t gfp) | |
371c752d MW |
1806 | { |
1807 | XA_STATE(xas, xa, 0); | |
371c752d | 1808 | |
76b4e529 | 1809 | if (WARN_ON_ONCE(xa_is_advanced(entry))) |
371c752d MW |
1810 | return -EINVAL; |
1811 | if (WARN_ON_ONCE(!xa_track_free(xa))) | |
1812 | return -EINVAL; | |
1813 | ||
1814 | if (!entry) | |
1815 | entry = XA_ZERO_ENTRY; | |
1816 | ||
1817 | do { | |
a3e4d3f9 MW |
1818 | xas.xa_index = limit.min; |
1819 | xas_find_marked(&xas, limit.max, XA_FREE_MARK); | |
371c752d | 1820 | if (xas.xa_node == XAS_RESTART) |
a3e4d3f9 MW |
1821 | xas_set_err(&xas, -EBUSY); |
1822 | else | |
1823 | *id = xas.xa_index; | |
371c752d MW |
1824 | xas_store(&xas, entry); |
1825 | xas_clear_mark(&xas, XA_FREE_MARK); | |
1826 | } while (__xas_nomem(&xas, gfp)); | |
1827 | ||
a3e4d3f9 | 1828 | return xas_error(&xas); |
371c752d MW |
1829 | } |
1830 | EXPORT_SYMBOL(__xa_alloc); | |
1831 | ||
2fa044e5 MW |
1832 | /** |
1833 | * __xa_alloc_cyclic() - Find somewhere to store this entry in the XArray. | |
1834 | * @xa: XArray. | |
1835 | * @id: Pointer to ID. | |
1836 | * @entry: New entry. | |
1837 | * @limit: Range of allocated ID. | |
1838 | * @next: Pointer to next ID to allocate. | |
1839 | * @gfp: Memory allocation flags. | |
1840 | * | |
1841 | * Finds an empty entry in @xa between @limit.min and @limit.max, | |
1842 | * stores the index into the @id pointer, then stores the entry at | |
1843 | * that index. A concurrent lookup will not see an uninitialised @id. | |
1844 | * The search for an empty entry will start at @next and will wrap | |
1845 | * around if necessary. | |
1846 | * | |
1847 | * Context: Any context. Expects xa_lock to be held on entry. May | |
1848 | * release and reacquire xa_lock if @gfp flags permit. | |
1849 | * Return: 0 if the allocation succeeded without wrapping. 1 if the | |
1850 | * allocation succeeded after wrapping, -ENOMEM if memory could not be | |
1851 | * allocated or -EBUSY if there are no free entries in @limit. | |
1852 | */ | |
1853 | int __xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, | |
1854 | struct xa_limit limit, u32 *next, gfp_t gfp) | |
1855 | { | |
1856 | u32 min = limit.min; | |
1857 | int ret; | |
1858 | ||
1859 | limit.min = max(min, *next); | |
1860 | ret = __xa_alloc(xa, id, entry, limit, gfp); | |
1861 | if ((xa->xa_flags & XA_FLAGS_ALLOC_WRAPPED) && ret == 0) { | |
1862 | xa->xa_flags &= ~XA_FLAGS_ALLOC_WRAPPED; | |
1863 | ret = 1; | |
1864 | } | |
1865 | ||
1866 | if (ret < 0 && limit.min > min) { | |
1867 | limit.min = min; | |
1868 | ret = __xa_alloc(xa, id, entry, limit, gfp); | |
1869 | if (ret == 0) | |
1870 | ret = 1; | |
1871 | } | |
1872 | ||
1873 | if (ret >= 0) { | |
1874 | *next = *id + 1; | |
1875 | if (*next == 0) | |
1876 | xa->xa_flags |= XA_FLAGS_ALLOC_WRAPPED; | |
1877 | } | |
1878 | return ret; | |
1879 | } | |
1880 | EXPORT_SYMBOL(__xa_alloc_cyclic); | |
1881 | ||
9b89a035 MW |
1882 | /** |
1883 | * __xa_set_mark() - Set this mark on this entry while locked. | |
1884 | * @xa: XArray. | |
1885 | * @index: Index of entry. | |
1886 | * @mark: Mark number. | |
1887 | * | |
804dfaf0 | 1888 | * Attempting to set a mark on a %NULL entry does not succeed. |
9b89a035 MW |
1889 | * |
1890 | * Context: Any context. Expects xa_lock to be held on entry. | |
1891 | */ | |
1892 | void __xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1893 | { | |
1894 | XA_STATE(xas, xa, index); | |
1895 | void *entry = xas_load(&xas); | |
1896 | ||
1897 | if (entry) | |
1898 | xas_set_mark(&xas, mark); | |
1899 | } | |
9ee5a3b7 | 1900 | EXPORT_SYMBOL(__xa_set_mark); |
9b89a035 MW |
1901 | |
1902 | /** | |
1903 | * __xa_clear_mark() - Clear this mark on this entry while locked. | |
1904 | * @xa: XArray. | |
1905 | * @index: Index of entry. | |
1906 | * @mark: Mark number. | |
1907 | * | |
1908 | * Context: Any context. Expects xa_lock to be held on entry. | |
1909 | */ | |
1910 | void __xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1911 | { | |
1912 | XA_STATE(xas, xa, index); | |
1913 | void *entry = xas_load(&xas); | |
1914 | ||
1915 | if (entry) | |
1916 | xas_clear_mark(&xas, mark); | |
1917 | } | |
9ee5a3b7 | 1918 | EXPORT_SYMBOL(__xa_clear_mark); |
9b89a035 MW |
1919 | |
1920 | /** | |
1921 | * xa_get_mark() - Inquire whether this mark is set on this entry. | |
1922 | * @xa: XArray. | |
1923 | * @index: Index of entry. | |
1924 | * @mark: Mark number. | |
1925 | * | |
1926 | * This function uses the RCU read lock, so the result may be out of date | |
1927 | * by the time it returns. If you need the result to be stable, use a lock. | |
1928 | * | |
1929 | * Context: Any context. Takes and releases the RCU lock. | |
1930 | * Return: True if the entry at @index has this mark set, false if it doesn't. | |
1931 | */ | |
1932 | bool xa_get_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1933 | { | |
1934 | XA_STATE(xas, xa, index); | |
1935 | void *entry; | |
1936 | ||
1937 | rcu_read_lock(); | |
1938 | entry = xas_start(&xas); | |
1939 | while (xas_get_mark(&xas, mark)) { | |
1940 | if (!xa_is_node(entry)) | |
1941 | goto found; | |
1942 | entry = xas_descend(&xas, xa_to_node(entry)); | |
1943 | } | |
1944 | rcu_read_unlock(); | |
1945 | return false; | |
1946 | found: | |
1947 | rcu_read_unlock(); | |
1948 | return true; | |
1949 | } | |
1950 | EXPORT_SYMBOL(xa_get_mark); | |
1951 | ||
1952 | /** | |
1953 | * xa_set_mark() - Set this mark on this entry. | |
1954 | * @xa: XArray. | |
1955 | * @index: Index of entry. | |
1956 | * @mark: Mark number. | |
1957 | * | |
804dfaf0 | 1958 | * Attempting to set a mark on a %NULL entry does not succeed. |
9b89a035 MW |
1959 | * |
1960 | * Context: Process context. Takes and releases the xa_lock. | |
1961 | */ | |
1962 | void xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1963 | { | |
1964 | xa_lock(xa); | |
1965 | __xa_set_mark(xa, index, mark); | |
1966 | xa_unlock(xa); | |
1967 | } | |
1968 | EXPORT_SYMBOL(xa_set_mark); | |
1969 | ||
1970 | /** | |
1971 | * xa_clear_mark() - Clear this mark on this entry. | |
1972 | * @xa: XArray. | |
1973 | * @index: Index of entry. | |
1974 | * @mark: Mark number. | |
1975 | * | |
1976 | * Clearing a mark always succeeds. | |
1977 | * | |
1978 | * Context: Process context. Takes and releases the xa_lock. | |
1979 | */ | |
1980 | void xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) | |
1981 | { | |
1982 | xa_lock(xa); | |
1983 | __xa_clear_mark(xa, index, mark); | |
1984 | xa_unlock(xa); | |
1985 | } | |
1986 | EXPORT_SYMBOL(xa_clear_mark); | |
1987 | ||
b803b428 MW |
1988 | /** |
1989 | * xa_find() - Search the XArray for an entry. | |
1990 | * @xa: XArray. | |
1991 | * @indexp: Pointer to an index. | |
1992 | * @max: Maximum index to search to. | |
1993 | * @filter: Selection criterion. | |
1994 | * | |
1995 | * Finds the entry in @xa which matches the @filter, and has the lowest | |
1996 | * index that is at least @indexp and no more than @max. | |
1997 | * If an entry is found, @indexp is updated to be the index of the entry. | |
1998 | * This function is protected by the RCU read lock, so it may not find | |
1999 | * entries which are being simultaneously added. It will not return an | |
2000 | * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). | |
2001 | * | |
2002 | * Context: Any context. Takes and releases the RCU lock. | |
2003 | * Return: The entry, if found, otherwise %NULL. | |
2004 | */ | |
2005 | void *xa_find(struct xarray *xa, unsigned long *indexp, | |
2006 | unsigned long max, xa_mark_t filter) | |
2007 | { | |
2008 | XA_STATE(xas, xa, *indexp); | |
2009 | void *entry; | |
2010 | ||
2011 | rcu_read_lock(); | |
2012 | do { | |
2013 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
2014 | entry = xas_find_marked(&xas, max, filter); | |
2015 | else | |
2016 | entry = xas_find(&xas, max); | |
2017 | } while (xas_retry(&xas, entry)); | |
2018 | rcu_read_unlock(); | |
2019 | ||
2020 | if (entry) | |
2021 | *indexp = xas.xa_index; | |
2022 | return entry; | |
2023 | } | |
2024 | EXPORT_SYMBOL(xa_find); | |
2025 | ||
19c30f4d MWO |
2026 | static bool xas_sibling(struct xa_state *xas) |
2027 | { | |
2028 | struct xa_node *node = xas->xa_node; | |
2029 | unsigned long mask; | |
2030 | ||
d8e93e3f | 2031 | if (!IS_ENABLED(CONFIG_XARRAY_MULTI) || !node) |
19c30f4d MWO |
2032 | return false; |
2033 | mask = (XA_CHUNK_SIZE << node->shift) - 1; | |
bd40b17c MWO |
2034 | return (xas->xa_index & mask) > |
2035 | ((unsigned long)xas->xa_offset << node->shift); | |
19c30f4d MWO |
2036 | } |
2037 | ||
b803b428 MW |
2038 | /** |
2039 | * xa_find_after() - Search the XArray for a present entry. | |
2040 | * @xa: XArray. | |
2041 | * @indexp: Pointer to an index. | |
2042 | * @max: Maximum index to search to. | |
2043 | * @filter: Selection criterion. | |
2044 | * | |
2045 | * Finds the entry in @xa which matches the @filter and has the lowest | |
2046 | * index that is above @indexp and no more than @max. | |
2047 | * If an entry is found, @indexp is updated to be the index of the entry. | |
2048 | * This function is protected by the RCU read lock, so it may miss entries | |
2049 | * which are being simultaneously added. It will not return an | |
2050 | * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). | |
2051 | * | |
2052 | * Context: Any context. Takes and releases the RCU lock. | |
2053 | * Return: The pointer, if found, otherwise %NULL. | |
2054 | */ | |
2055 | void *xa_find_after(struct xarray *xa, unsigned long *indexp, | |
2056 | unsigned long max, xa_mark_t filter) | |
2057 | { | |
2058 | XA_STATE(xas, xa, *indexp + 1); | |
2059 | void *entry; | |
2060 | ||
430f24f9 MWO |
2061 | if (xas.xa_index == 0) |
2062 | return NULL; | |
2063 | ||
b803b428 MW |
2064 | rcu_read_lock(); |
2065 | for (;;) { | |
2066 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
2067 | entry = xas_find_marked(&xas, max, filter); | |
2068 | else | |
2069 | entry = xas_find(&xas, max); | |
c44aa5e8 MWO |
2070 | |
2071 | if (xas_invalid(&xas)) | |
8229706e | 2072 | break; |
19c30f4d MWO |
2073 | if (xas_sibling(&xas)) |
2074 | continue; | |
b803b428 MW |
2075 | if (!xas_retry(&xas, entry)) |
2076 | break; | |
2077 | } | |
2078 | rcu_read_unlock(); | |
2079 | ||
2080 | if (entry) | |
2081 | *indexp = xas.xa_index; | |
2082 | return entry; | |
2083 | } | |
2084 | EXPORT_SYMBOL(xa_find_after); | |
2085 | ||
80a0a1a9 MW |
2086 | static unsigned int xas_extract_present(struct xa_state *xas, void **dst, |
2087 | unsigned long max, unsigned int n) | |
2088 | { | |
2089 | void *entry; | |
2090 | unsigned int i = 0; | |
2091 | ||
2092 | rcu_read_lock(); | |
2093 | xas_for_each(xas, entry, max) { | |
2094 | if (xas_retry(xas, entry)) | |
2095 | continue; | |
2096 | dst[i++] = entry; | |
2097 | if (i == n) | |
2098 | break; | |
2099 | } | |
2100 | rcu_read_unlock(); | |
2101 | ||
2102 | return i; | |
2103 | } | |
2104 | ||
2105 | static unsigned int xas_extract_marked(struct xa_state *xas, void **dst, | |
2106 | unsigned long max, unsigned int n, xa_mark_t mark) | |
2107 | { | |
2108 | void *entry; | |
2109 | unsigned int i = 0; | |
2110 | ||
2111 | rcu_read_lock(); | |
2112 | xas_for_each_marked(xas, entry, max, mark) { | |
2113 | if (xas_retry(xas, entry)) | |
2114 | continue; | |
2115 | dst[i++] = entry; | |
2116 | if (i == n) | |
2117 | break; | |
2118 | } | |
2119 | rcu_read_unlock(); | |
2120 | ||
2121 | return i; | |
2122 | } | |
2123 | ||
2124 | /** | |
2125 | * xa_extract() - Copy selected entries from the XArray into a normal array. | |
2126 | * @xa: The source XArray to copy from. | |
2127 | * @dst: The buffer to copy entries into. | |
2128 | * @start: The first index in the XArray eligible to be selected. | |
2129 | * @max: The last index in the XArray eligible to be selected. | |
2130 | * @n: The maximum number of entries to copy. | |
2131 | * @filter: Selection criterion. | |
2132 | * | |
2133 | * Copies up to @n entries that match @filter from the XArray. The | |
2134 | * copied entries will have indices between @start and @max, inclusive. | |
2135 | * | |
2136 | * The @filter may be an XArray mark value, in which case entries which are | |
2137 | * marked with that mark will be copied. It may also be %XA_PRESENT, in | |
804dfaf0 | 2138 | * which case all entries which are not %NULL will be copied. |
80a0a1a9 MW |
2139 | * |
2140 | * The entries returned may not represent a snapshot of the XArray at a | |
2141 | * moment in time. For example, if another thread stores to index 5, then | |
2142 | * index 10, calling xa_extract() may return the old contents of index 5 | |
2143 | * and the new contents of index 10. Indices not modified while this | |
2144 | * function is running will not be skipped. | |
2145 | * | |
2146 | * If you need stronger guarantees, holding the xa_lock across calls to this | |
2147 | * function will prevent concurrent modification. | |
2148 | * | |
2149 | * Context: Any context. Takes and releases the RCU lock. | |
2150 | * Return: The number of entries copied. | |
2151 | */ | |
2152 | unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, | |
2153 | unsigned long max, unsigned int n, xa_mark_t filter) | |
2154 | { | |
2155 | XA_STATE(xas, xa, start); | |
2156 | ||
2157 | if (!n) | |
2158 | return 0; | |
2159 | ||
2160 | if ((__force unsigned int)filter < XA_MAX_MARKS) | |
2161 | return xas_extract_marked(&xas, dst, max, n, filter); | |
2162 | return xas_extract_present(&xas, dst, max, n); | |
2163 | } | |
2164 | EXPORT_SYMBOL(xa_extract); | |
2165 | ||
f82cd2f0 MWO |
2166 | /** |
2167 | * xa_delete_node() - Private interface for workingset code. | |
2168 | * @node: Node to be removed from the tree. | |
2169 | * @update: Function to call to update ancestor nodes. | |
2170 | * | |
2171 | * Context: xa_lock must be held on entry and will not be released. | |
2172 | */ | |
2173 | void xa_delete_node(struct xa_node *node, xa_update_node_t update) | |
2174 | { | |
2175 | struct xa_state xas = { | |
2176 | .xa = node->array, | |
2177 | .xa_index = (unsigned long)node->offset << | |
2178 | (node->shift + XA_CHUNK_SHIFT), | |
2179 | .xa_shift = node->shift + XA_CHUNK_SHIFT, | |
2180 | .xa_offset = node->offset, | |
2181 | .xa_node = xa_parent_locked(node->array, node), | |
2182 | .xa_update = update, | |
2183 | }; | |
2184 | ||
2185 | xas_store(&xas, NULL); | |
2186 | } | |
2187 | EXPORT_SYMBOL_GPL(xa_delete_node); /* For the benefit of the test suite */ | |
2188 | ||
687149fc MW |
2189 | /** |
2190 | * xa_destroy() - Free all internal data structures. | |
2191 | * @xa: XArray. | |
2192 | * | |
2193 | * After calling this function, the XArray is empty and has freed all memory | |
2194 | * allocated for its internal data structures. You are responsible for | |
2195 | * freeing the objects referenced by the XArray. | |
2196 | * | |
2197 | * Context: Any context. Takes and releases the xa_lock, interrupt-safe. | |
2198 | */ | |
2199 | void xa_destroy(struct xarray *xa) | |
2200 | { | |
2201 | XA_STATE(xas, xa, 0); | |
2202 | unsigned long flags; | |
2203 | void *entry; | |
2204 | ||
2205 | xas.xa_node = NULL; | |
2206 | xas_lock_irqsave(&xas, flags); | |
2207 | entry = xa_head_locked(xa); | |
2208 | RCU_INIT_POINTER(xa->xa_head, NULL); | |
2209 | xas_init_marks(&xas); | |
3ccaf57a MW |
2210 | if (xa_zero_busy(xa)) |
2211 | xa_mark_clear(xa, XA_FREE_MARK); | |
687149fc MW |
2212 | /* lockdep checks we're still holding the lock in xas_free_nodes() */ |
2213 | if (xa_is_node(entry)) | |
2214 | xas_free_nodes(&xas, xa_to_node(entry)); | |
2215 | xas_unlock_irqrestore(&xas, flags); | |
2216 | } | |
2217 | EXPORT_SYMBOL(xa_destroy); | |
2218 | ||
ad3d6c72 MW |
2219 | #ifdef XA_DEBUG |
2220 | void xa_dump_node(const struct xa_node *node) | |
2221 | { | |
2222 | unsigned i, j; | |
2223 | ||
2224 | if (!node) | |
2225 | return; | |
2226 | if ((unsigned long)node & 3) { | |
2227 | pr_cont("node %px\n", node); | |
2228 | return; | |
2229 | } | |
2230 | ||
2231 | pr_cont("node %px %s %d parent %px shift %d count %d values %d " | |
2232 | "array %px list %px %px marks", | |
2233 | node, node->parent ? "offset" : "max", node->offset, | |
2234 | node->parent, node->shift, node->count, node->nr_values, | |
2235 | node->array, node->private_list.prev, node->private_list.next); | |
2236 | for (i = 0; i < XA_MAX_MARKS; i++) | |
2237 | for (j = 0; j < XA_MARK_LONGS; j++) | |
2238 | pr_cont(" %lx", node->marks[i][j]); | |
2239 | pr_cont("\n"); | |
2240 | } | |
2241 | ||
2242 | void xa_dump_index(unsigned long index, unsigned int shift) | |
2243 | { | |
2244 | if (!shift) | |
2245 | pr_info("%lu: ", index); | |
2246 | else if (shift >= BITS_PER_LONG) | |
2247 | pr_info("0-%lu: ", ~0UL); | |
2248 | else | |
2249 | pr_info("%lu-%lu: ", index, index | ((1UL << shift) - 1)); | |
2250 | } | |
2251 | ||
2252 | void xa_dump_entry(const void *entry, unsigned long index, unsigned long shift) | |
2253 | { | |
2254 | if (!entry) | |
2255 | return; | |
2256 | ||
2257 | xa_dump_index(index, shift); | |
2258 | ||
2259 | if (xa_is_node(entry)) { | |
2260 | if (shift == 0) { | |
2261 | pr_cont("%px\n", entry); | |
2262 | } else { | |
2263 | unsigned long i; | |
2264 | struct xa_node *node = xa_to_node(entry); | |
2265 | xa_dump_node(node); | |
2266 | for (i = 0; i < XA_CHUNK_SIZE; i++) | |
2267 | xa_dump_entry(node->slots[i], | |
2268 | index + (i << node->shift), node->shift); | |
2269 | } | |
2270 | } else if (xa_is_value(entry)) | |
2271 | pr_cont("value %ld (0x%lx) [%px]\n", xa_to_value(entry), | |
2272 | xa_to_value(entry), entry); | |
2273 | else if (!xa_is_internal(entry)) | |
2274 | pr_cont("%px\n", entry); | |
2275 | else if (xa_is_retry(entry)) | |
2276 | pr_cont("retry (%ld)\n", xa_to_internal(entry)); | |
2277 | else if (xa_is_sibling(entry)) | |
2278 | pr_cont("sibling (slot %ld)\n", xa_to_sibling(entry)); | |
9f14d4f1 MW |
2279 | else if (xa_is_zero(entry)) |
2280 | pr_cont("zero (%ld)\n", xa_to_internal(entry)); | |
ad3d6c72 MW |
2281 | else |
2282 | pr_cont("UNKNOWN ENTRY (%px)\n", entry); | |
2283 | } | |
2284 | ||
2285 | void xa_dump(const struct xarray *xa) | |
2286 | { | |
2287 | void *entry = xa->xa_head; | |
2288 | unsigned int shift = 0; | |
2289 | ||
2290 | pr_info("xarray: %px head %px flags %x marks %d %d %d\n", xa, entry, | |
9b89a035 MW |
2291 | xa->xa_flags, xa_marked(xa, XA_MARK_0), |
2292 | xa_marked(xa, XA_MARK_1), xa_marked(xa, XA_MARK_2)); | |
ad3d6c72 MW |
2293 | if (xa_is_node(entry)) |
2294 | shift = xa_to_node(entry)->shift + XA_CHUNK_SHIFT; | |
2295 | xa_dump_entry(entry, 0, shift); | |
2296 | } | |
2297 | #endif |