1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
2 | #ifndef _LINUX_XARRAY_H |
3 | #define _LINUX_XARRAY_H |
4 | /* |
5 | * eXtensible Arrays |
6 | * Copyright (c) 2017 Microsoft Corporation |
7 | * Author: Matthew Wilcox <willy@infradead.org> |
8 | * |
9 | * See Documentation/core-api/xarray.rst for how to use the XArray. |
10 | */ |
11 | |
12 | #include <linux/bitmap.h> |
13 | #include <linux/bug.h> |
14 | #include <linux/compiler.h> |
15 | #include <linux/gfp.h> |
16 | #include <linux/kconfig.h> |
17 | #include <linux/kernel.h> |
18 | #include <linux/rcupdate.h> |
19 | #include <linux/sched/mm.h> |
20 | #include <linux/spinlock.h> |
21 | #include <linux/types.h> |
22 | |
23 | /* |
24 | * The bottom two bits of the entry determine how the XArray interprets |
25 | * the contents: |
26 | * |
27 | * 00: Pointer entry |
28 | * 10: Internal entry |
29 | * x1: Value entry or tagged pointer |
30 | * |
31 | * Attempting to store internal entries in the XArray is a bug. |
32 | * |
33 | * Most internal entries are pointers to the next node in the tree. |
34 | * The following internal entries have a special meaning: |
35 | * |
36 | * 0-62: Sibling entries |
37 | * 256: Retry entry |
38 | * 257: Zero entry |
39 | * |
40 | * Errors are also represented as internal entries, but use the negative |
41 | * space (-4094 to -2). They're never stored in the slots array; only |
42 | * returned by the normal API. |
43 | */ |
44 | |
45 | #define BITS_PER_XA_VALUE (BITS_PER_LONG - 1) |
46 | |
47 | /** |
48 | * xa_mk_value() - Create an XArray entry from an integer. |
49 | * @v: Value to store in XArray. |
50 | * |
51 | * Context: Any context. |
52 | * Return: An entry suitable for storing in the XArray. |
53 | */ |
54 | static inline void *xa_mk_value(unsigned long v) |
55 | { |
56 | WARN_ON((long)v < 0); |
57 | return (void *)((v << 1) | 1); |
58 | } |
59 | |
60 | /** |
61 | * xa_to_value() - Get value stored in an XArray entry. |
62 | * @entry: XArray entry. |
63 | * |
64 | * Context: Any context. |
65 | * Return: The value stored in the XArray entry. |
66 | */ |
67 | static inline unsigned long xa_to_value(const void *entry) |
68 | { |
69 | return (unsigned long)entry >> 1; |
70 | } |
71 | |
72 | /** |
73 | * xa_is_value() - Determine if an entry is a value. |
74 | * @entry: XArray entry. |
75 | * |
76 | * Context: Any context. |
77 | * Return: True if the entry is a value, false if it is a pointer. |
78 | */ |
79 | static inline bool xa_is_value(const void *entry) |
80 | { |
81 | return (unsigned long)entry & 1; |
82 | } |
83 | |
84 | /** |
85 | * xa_tag_pointer() - Create an XArray entry for a tagged pointer. |
86 | * @p: Plain pointer. |
87 | * @tag: Tag value (0, 1 or 3). |
88 | * |
89 | * If the user of the XArray prefers, they can tag their pointers instead |
90 | * of storing value entries. Three tags are available (0, 1 and 3). |
91 | * These are distinct from the xa_mark_t as they are not replicated up |
92 | * through the array and cannot be searched for. |
93 | * |
94 | * Context: Any context. |
95 | * Return: An XArray entry. |
96 | */ |
97 | static inline void *xa_tag_pointer(void *p, unsigned long tag) |
98 | { |
99 | return (void *)((unsigned long)p | tag); |
100 | } |
101 | |
102 | /** |
103 | * xa_untag_pointer() - Turn an XArray entry into a plain pointer. |
104 | * @entry: XArray entry. |
105 | * |
106 | * If you have stored a tagged pointer in the XArray, call this function |
107 | * to get the untagged version of the pointer. |
108 | * |
109 | * Context: Any context. |
110 | * Return: A pointer. |
111 | */ |
112 | static inline void *xa_untag_pointer(void *entry) |
113 | { |
114 | return (void *)((unsigned long)entry & ~3UL); |
115 | } |
116 | |
117 | /** |
118 | * xa_pointer_tag() - Get the tag stored in an XArray entry. |
119 | * @entry: XArray entry. |
120 | * |
121 | * If you have stored a tagged pointer in the XArray, call this function |
122 | * to get the tag of that pointer. |
123 | * |
124 | * Context: Any context. |
125 | * Return: A tag. |
126 | */ |
127 | static inline unsigned int xa_pointer_tag(void *entry) |
128 | { |
129 | return (unsigned long)entry & 3UL; |
130 | } |
131 | |
132 | /* |
133 | * xa_mk_internal() - Create an internal entry. |
134 | * @v: Value to turn into an internal entry. |
135 | * |
136 | * Internal entries are used for a number of purposes. Entries 0-255 are |
137 | * used for sibling entries (only 0-62 are used by the current code). 256 |
138 | * is used for the retry entry. 257 is used for the reserved / zero entry. |
139 | * Negative internal entries are used to represent errnos. Node pointers |
140 | * are also tagged as internal entries in some situations. |
141 | * |
142 | * Context: Any context. |
143 | * Return: An XArray internal entry corresponding to this value. |
144 | */ |
145 | static inline void *xa_mk_internal(unsigned long v) |
146 | { |
147 | return (void *)((v << 2) | 2); |
148 | } |
149 | |
150 | /* |
151 | * xa_to_internal() - Extract the value from an internal entry. |
152 | * @entry: XArray entry. |
153 | * |
154 | * Context: Any context. |
155 | * Return: The value which was stored in the internal entry. |
156 | */ |
157 | static inline unsigned long xa_to_internal(const void *entry) |
158 | { |
159 | return (unsigned long)entry >> 2; |
160 | } |
161 | |
162 | /* |
163 | * xa_is_internal() - Is the entry an internal entry? |
164 | * @entry: XArray entry. |
165 | * |
166 | * Context: Any context. |
167 | * Return: %true if the entry is an internal entry. |
168 | */ |
169 | static inline bool xa_is_internal(const void *entry) |
170 | { |
171 | return ((unsigned long)entry & 3) == 2; |
172 | } |
173 | |
174 | #define XA_ZERO_ENTRY xa_mk_internal(257) |
175 | |
176 | /** |
177 | * xa_is_zero() - Is the entry a zero entry? |
178 | * @entry: Entry retrieved from the XArray |
179 | * |
180 | * The normal API will return NULL as the contents of a slot containing |
181 | * a zero entry. You can only see zero entries by using the advanced API. |
182 | * |
183 | * Return: %true if the entry is a zero entry. |
184 | */ |
185 | static inline bool xa_is_zero(const void *entry) |
186 | { |
187 | return unlikely(entry == XA_ZERO_ENTRY); |
188 | } |
189 | |
190 | /** |
191 | * xa_is_err() - Report whether an XArray operation returned an error |
192 | * @entry: Result from calling an XArray function |
193 | * |
194 | * If an XArray operation cannot complete an operation, it will return |
195 | * a special value indicating an error. This function tells you |
196 | * whether an error occurred; xa_err() tells you which error occurred. |
197 | * |
198 | * Context: Any context. |
199 | * Return: %true if the entry indicates an error. |
200 | */ |
201 | static inline bool xa_is_err(const void *entry) |
202 | { |
203 | return unlikely(xa_is_internal(entry) && |
204 | entry >= xa_mk_internal(-MAX_ERRNO)); |
205 | } |
206 | |
207 | /** |
208 | * xa_err() - Turn an XArray result into an errno. |
209 | * @entry: Result from calling an XArray function. |
210 | * |
211 | * If an XArray operation cannot complete an operation, it will return |
212 | * a special pointer value which encodes an errno. This function extracts |
213 | * the errno from the pointer value, or returns 0 if the pointer does not |
214 | * represent an errno. |
215 | * |
216 | * Context: Any context. |
217 | * Return: A negative errno or 0. |
218 | */ |
219 | static inline int xa_err(void *entry) |
220 | { |
221 | /* xa_to_internal() would not do sign extension. */ |
222 | if (xa_is_err(entry)) |
223 | return (long)entry >> 2; |
224 | return 0; |
225 | } |
226 | |
227 | /** |
228 | * struct xa_limit - Represents a range of IDs. |
229 | * @min: The lowest ID to allocate (inclusive). |
230 | * @max: The maximum ID to allocate (inclusive). |
231 | * |
232 | * This structure is used either directly or via the XA_LIMIT() macro |
233 | * to communicate the range of IDs that are valid for allocation. |
234 | * Three common ranges are predefined for you: |
235 | * * xa_limit_32b - [0 - UINT_MAX] |
236 | * * xa_limit_31b - [0 - INT_MAX] |
237 | * * xa_limit_16b - [0 - USHRT_MAX] |
238 | */ |
239 | struct xa_limit { |
240 | u32 max; |
241 | u32 min; |
242 | }; |
243 | |
244 | #define XA_LIMIT(_min, _max) (struct xa_limit) { .min = _min, .max = _max } |
245 | |
246 | #define xa_limit_32b XA_LIMIT(0, UINT_MAX) |
247 | #define xa_limit_31b XA_LIMIT(0, INT_MAX) |
248 | #define xa_limit_16b XA_LIMIT(0, USHRT_MAX) |
249 | |
250 | typedef unsigned __bitwise xa_mark_t; |
251 | #define XA_MARK_0 ((__force xa_mark_t)0U) |
252 | #define XA_MARK_1 ((__force xa_mark_t)1U) |
253 | #define XA_MARK_2 ((__force xa_mark_t)2U) |
254 | #define XA_PRESENT ((__force xa_mark_t)8U) |
255 | #define XA_MARK_MAX XA_MARK_2 |
256 | #define XA_FREE_MARK XA_MARK_0 |
257 | |
258 | enum xa_lock_type { |
259 | XA_LOCK_IRQ = 1, |
260 | XA_LOCK_BH = 2, |
261 | }; |
262 | |
263 | /* |
264 | * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags, |
265 | * and we remain compatible with that. |
266 | */ |
267 | #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) |
268 | #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) |
269 | #define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U) |
270 | #define XA_FLAGS_ZERO_BUSY ((__force gfp_t)8U) |
271 | #define XA_FLAGS_ALLOC_WRAPPED ((__force gfp_t)16U) |
272 | #define XA_FLAGS_ACCOUNT ((__force gfp_t)32U) |
273 | #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ |
274 | (__force unsigned)(mark))) |
275 | |
276 | /* ALLOC is for a normal 0-based alloc. ALLOC1 is for an 1-based alloc */ |
277 | #define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK)) |
278 | #define XA_FLAGS_ALLOC1 (XA_FLAGS_TRACK_FREE | XA_FLAGS_ZERO_BUSY) |
279 | |
280 | /** |
281 | * struct xarray - The anchor of the XArray. |
282 | * @xa_lock: Lock that protects the contents of the XArray. |
283 | * |
284 | * To use the xarray, define it statically or embed it in your data structure. |
285 | * It is a very small data structure, so it does not usually make sense to |
286 | * allocate it separately and keep a pointer to it in your data structure. |
287 | * |
288 | * You may use the xa_lock to protect your own data structures as well. |
289 | */ |
290 | /* |
291 | * If all of the entries in the array are NULL, @xa_head is a NULL pointer. |
292 | * If the only non-NULL entry in the array is at index 0, @xa_head is that |
293 | * entry. If any other entry in the array is non-NULL, @xa_head points |
294 | * to an @xa_node. |
295 | */ |
296 | struct xarray { |
297 | spinlock_t xa_lock; |
298 | /* private: The rest of the data structure is not to be used directly. */ |
299 | gfp_t xa_flags; |
300 | void __rcu * xa_head; |
301 | }; |
302 | |
303 | #define XARRAY_INIT(name, flags) { \ |
304 | .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \ |
305 | .xa_flags = flags, \ |
306 | .xa_head = NULL, \ |
307 | } |
308 | |
309 | /** |
310 | * DEFINE_XARRAY_FLAGS() - Define an XArray with custom flags. |
311 | * @name: A string that names your XArray. |
312 | * @flags: XA_FLAG values. |
313 | * |
314 | * This is intended for file scope definitions of XArrays. It declares |
315 | * and initialises an empty XArray with the chosen name and flags. It is |
316 | * equivalent to calling xa_init_flags() on the array, but it does the |
317 | * initialisation at compiletime instead of runtime. |
318 | */ |
319 | #define DEFINE_XARRAY_FLAGS(name, flags) \ |
320 | struct xarray name = XARRAY_INIT(name, flags) |
321 | |
322 | /** |
323 | * DEFINE_XARRAY() - Define an XArray. |
324 | * @name: A string that names your XArray. |
325 | * |
326 | * This is intended for file scope definitions of XArrays. It declares |
327 | * and initialises an empty XArray with the chosen name. It is equivalent |
328 | * to calling xa_init() on the array, but it does the initialisation at |
329 | * compiletime instead of runtime. |
330 | */ |
331 | #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) |
332 | |
333 | /** |
334 | * DEFINE_XARRAY_ALLOC() - Define an XArray which allocates IDs starting at 0. |
335 | * @name: A string that names your XArray. |
336 | * |
337 | * This is intended for file scope definitions of allocating XArrays. |
338 | * See also DEFINE_XARRAY(). |
339 | */ |
340 | #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) |
341 | |
342 | /** |
343 | * DEFINE_XARRAY_ALLOC1() - Define an XArray which allocates IDs starting at 1. |
344 | * @name: A string that names your XArray. |
345 | * |
346 | * This is intended for file scope definitions of allocating XArrays. |
347 | * See also DEFINE_XARRAY(). |
348 | */ |
349 | #define DEFINE_XARRAY_ALLOC1(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC1) |
350 | |
351 | void *xa_load(struct xarray *, unsigned long index); |
352 | void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); |
353 | void *xa_erase(struct xarray *, unsigned long index); |
354 | void *xa_store_range(struct xarray *, unsigned long first, unsigned long last, |
355 | void *entry, gfp_t); |
356 | bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); |
357 | void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); |
358 | void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); |
359 | void *xa_find(struct xarray *xa, unsigned long *index, |
360 | unsigned long max, xa_mark_t) __attribute__((nonnull(2))); |
361 | void *xa_find_after(struct xarray *xa, unsigned long *index, |
362 | unsigned long max, xa_mark_t) __attribute__((nonnull(2))); |
363 | unsigned int (struct xarray *, void **dst, unsigned long start, |
364 | unsigned long max, unsigned int n, xa_mark_t); |
365 | void xa_destroy(struct xarray *); |
366 | |
367 | /** |
368 | * xa_init_flags() - Initialise an empty XArray with flags. |
369 | * @xa: XArray. |
370 | * @flags: XA_FLAG values. |
371 | * |
372 | * If you need to initialise an XArray with special flags (eg you need |
373 | * to take the lock from interrupt context), use this function instead |
374 | * of xa_init(). |
375 | * |
376 | * Context: Any context. |
377 | */ |
378 | static inline void xa_init_flags(struct xarray *xa, gfp_t flags) |
379 | { |
380 | spin_lock_init(&xa->xa_lock); |
381 | xa->xa_flags = flags; |
382 | xa->xa_head = NULL; |
383 | } |
384 | |
385 | /** |
386 | * xa_init() - Initialise an empty XArray. |
387 | * @xa: XArray. |
388 | * |
389 | * An empty XArray is full of NULL entries. |
390 | * |
391 | * Context: Any context. |
392 | */ |
393 | static inline void xa_init(struct xarray *xa) |
394 | { |
395 | xa_init_flags(xa, flags: 0); |
396 | } |
397 | |
398 | /** |
399 | * xa_empty() - Determine if an array has any present entries. |
400 | * @xa: XArray. |
401 | * |
402 | * Context: Any context. |
403 | * Return: %true if the array contains only NULL pointers. |
404 | */ |
405 | static inline bool xa_empty(const struct xarray *xa) |
406 | { |
407 | return xa->xa_head == NULL; |
408 | } |
409 | |
410 | /** |
411 | * xa_marked() - Inquire whether any entry in this array has a mark set |
412 | * @xa: Array |
413 | * @mark: Mark value |
414 | * |
415 | * Context: Any context. |
416 | * Return: %true if any entry has this mark set. |
417 | */ |
418 | static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) |
419 | { |
420 | return xa->xa_flags & XA_FLAGS_MARK(mark); |
421 | } |
422 | |
423 | /** |
424 | * xa_for_each_range() - Iterate over a portion of an XArray. |
425 | * @xa: XArray. |
426 | * @index: Index of @entry. |
427 | * @entry: Entry retrieved from array. |
428 | * @start: First index to retrieve from array. |
429 | * @last: Last index to retrieve from array. |
430 | * |
431 | * During the iteration, @entry will have the value of the entry stored |
432 | * in @xa at @index. You may modify @index during the iteration if you |
433 | * want to skip or reprocess indices. It is safe to modify the array |
434 | * during the iteration. At the end of the iteration, @entry will be set |
435 | * to NULL and @index will have a value less than or equal to max. |
436 | * |
437 | * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have |
438 | * to handle your own locking with xas_for_each(), and if you have to unlock |
439 | * after each iteration, it will also end up being O(n.log(n)). |
440 | * xa_for_each_range() will spin if it hits a retry entry; if you intend to |
441 | * see retry entries, you should use the xas_for_each() iterator instead. |
442 | * The xas_for_each() iterator will expand into more inline code than |
443 | * xa_for_each_range(). |
444 | * |
445 | * Context: Any context. Takes and releases the RCU lock. |
446 | */ |
447 | #define xa_for_each_range(xa, index, entry, start, last) \ |
448 | for (index = start, \ |
449 | entry = xa_find(xa, &index, last, XA_PRESENT); \ |
450 | entry; \ |
451 | entry = xa_find_after(xa, &index, last, XA_PRESENT)) |
452 | |
453 | /** |
454 | * xa_for_each_start() - Iterate over a portion of an XArray. |
455 | * @xa: XArray. |
456 | * @index: Index of @entry. |
457 | * @entry: Entry retrieved from array. |
458 | * @start: First index to retrieve from array. |
459 | * |
460 | * During the iteration, @entry will have the value of the entry stored |
461 | * in @xa at @index. You may modify @index during the iteration if you |
462 | * want to skip or reprocess indices. It is safe to modify the array |
463 | * during the iteration. At the end of the iteration, @entry will be set |
464 | * to NULL and @index will have a value less than or equal to max. |
465 | * |
466 | * xa_for_each_start() is O(n.log(n)) while xas_for_each() is O(n). You have |
467 | * to handle your own locking with xas_for_each(), and if you have to unlock |
468 | * after each iteration, it will also end up being O(n.log(n)). |
469 | * xa_for_each_start() will spin if it hits a retry entry; if you intend to |
470 | * see retry entries, you should use the xas_for_each() iterator instead. |
471 | * The xas_for_each() iterator will expand into more inline code than |
472 | * xa_for_each_start(). |
473 | * |
474 | * Context: Any context. Takes and releases the RCU lock. |
475 | */ |
476 | #define xa_for_each_start(xa, index, entry, start) \ |
477 | xa_for_each_range(xa, index, entry, start, ULONG_MAX) |
478 | |
479 | /** |
480 | * xa_for_each() - Iterate over present entries in an XArray. |
481 | * @xa: XArray. |
482 | * @index: Index of @entry. |
483 | * @entry: Entry retrieved from array. |
484 | * |
485 | * During the iteration, @entry will have the value of the entry stored |
486 | * in @xa at @index. You may modify @index during the iteration if you want |
487 | * to skip or reprocess indices. It is safe to modify the array during the |
488 | * iteration. At the end of the iteration, @entry will be set to NULL and |
489 | * @index will have a value less than or equal to max. |
490 | * |
491 | * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have |
492 | * to handle your own locking with xas_for_each(), and if you have to unlock |
493 | * after each iteration, it will also end up being O(n.log(n)). xa_for_each() |
494 | * will spin if it hits a retry entry; if you intend to see retry entries, |
495 | * you should use the xas_for_each() iterator instead. The xas_for_each() |
496 | * iterator will expand into more inline code than xa_for_each(). |
497 | * |
498 | * Context: Any context. Takes and releases the RCU lock. |
499 | */ |
500 | #define xa_for_each(xa, index, entry) \ |
501 | xa_for_each_start(xa, index, entry, 0) |
502 | |
503 | /** |
504 | * xa_for_each_marked() - Iterate over marked entries in an XArray. |
505 | * @xa: XArray. |
506 | * @index: Index of @entry. |
507 | * @entry: Entry retrieved from array. |
508 | * @filter: Selection criterion. |
509 | * |
510 | * During the iteration, @entry will have the value of the entry stored |
511 | * in @xa at @index. The iteration will skip all entries in the array |
512 | * which do not match @filter. You may modify @index during the iteration |
513 | * if you want to skip or reprocess indices. It is safe to modify the array |
514 | * during the iteration. At the end of the iteration, @entry will be set to |
515 | * NULL and @index will have a value less than or equal to max. |
516 | * |
517 | * xa_for_each_marked() is O(n.log(n)) while xas_for_each_marked() is O(n). |
518 | * You have to handle your own locking with xas_for_each(), and if you have |
519 | * to unlock after each iteration, it will also end up being O(n.log(n)). |
520 | * xa_for_each_marked() will spin if it hits a retry entry; if you intend to |
521 | * see retry entries, you should use the xas_for_each_marked() iterator |
522 | * instead. The xas_for_each_marked() iterator will expand into more inline |
523 | * code than xa_for_each_marked(). |
524 | * |
525 | * Context: Any context. Takes and releases the RCU lock. |
526 | */ |
527 | #define xa_for_each_marked(xa, index, entry, filter) \ |
528 | for (index = 0, entry = xa_find(xa, &index, ULONG_MAX, filter); \ |
529 | entry; entry = xa_find_after(xa, &index, ULONG_MAX, filter)) |
530 | |
531 | #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) |
532 | #define xa_lock(xa) spin_lock(&(xa)->xa_lock) |
533 | #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) |
534 | #define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock) |
535 | #define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock) |
536 | #define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock) |
537 | #define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock) |
538 | #define xa_lock_irqsave(xa, flags) \ |
539 | spin_lock_irqsave(&(xa)->xa_lock, flags) |
540 | #define xa_unlock_irqrestore(xa, flags) \ |
541 | spin_unlock_irqrestore(&(xa)->xa_lock, flags) |
542 | #define xa_lock_nested(xa, subclass) \ |
543 | spin_lock_nested(&(xa)->xa_lock, subclass) |
544 | #define xa_lock_bh_nested(xa, subclass) \ |
545 | spin_lock_bh_nested(&(xa)->xa_lock, subclass) |
546 | #define xa_lock_irq_nested(xa, subclass) \ |
547 | spin_lock_irq_nested(&(xa)->xa_lock, subclass) |
548 | #define xa_lock_irqsave_nested(xa, flags, subclass) \ |
549 | spin_lock_irqsave_nested(&(xa)->xa_lock, flags, subclass) |
550 | |
551 | /* |
552 | * Versions of the normal API which require the caller to hold the |
553 | * xa_lock. If the GFP flags allow it, they will drop the lock to |
554 | * allocate memory, then reacquire it afterwards. These functions |
555 | * may also re-enable interrupts if the XArray flags indicate the |
556 | * locking should be interrupt safe. |
557 | */ |
558 | void *__xa_erase(struct xarray *, unsigned long index); |
559 | void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); |
560 | void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old, |
561 | void *entry, gfp_t); |
562 | int __must_check __xa_insert(struct xarray *, unsigned long index, |
563 | void *entry, gfp_t); |
564 | int __must_check __xa_alloc(struct xarray *, u32 *id, void *entry, |
565 | struct xa_limit, gfp_t); |
566 | int __must_check __xa_alloc_cyclic(struct xarray *, u32 *id, void *entry, |
567 | struct xa_limit, u32 *next, gfp_t); |
568 | void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); |
569 | void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); |
570 | |
571 | /** |
572 | * xa_store_bh() - Store this entry in the XArray. |
573 | * @xa: XArray. |
574 | * @index: Index into array. |
575 | * @entry: New entry. |
576 | * @gfp: Memory allocation flags. |
577 | * |
578 | * This function is like calling xa_store() except it disables softirqs |
579 | * while holding the array lock. |
580 | * |
581 | * Context: Any context. Takes and releases the xa_lock while |
582 | * disabling softirqs. |
583 | * Return: The old entry at this index or xa_err() if an error happened. |
584 | */ |
585 | static inline void *xa_store_bh(struct xarray *xa, unsigned long index, |
586 | void *entry, gfp_t gfp) |
587 | { |
588 | void *curr; |
589 | |
590 | might_alloc(gfp_mask: gfp); |
591 | xa_lock_bh(xa); |
592 | curr = __xa_store(xa, index, entry, gfp); |
593 | xa_unlock_bh(xa); |
594 | |
595 | return curr; |
596 | } |
597 | |
598 | /** |
599 | * xa_store_irq() - Store this entry in the XArray. |
600 | * @xa: XArray. |
601 | * @index: Index into array. |
602 | * @entry: New entry. |
603 | * @gfp: Memory allocation flags. |
604 | * |
605 | * This function is like calling xa_store() except it disables interrupts |
606 | * while holding the array lock. |
607 | * |
608 | * Context: Process context. Takes and releases the xa_lock while |
609 | * disabling interrupts. |
610 | * Return: The old entry at this index or xa_err() if an error happened. |
611 | */ |
612 | static inline void *xa_store_irq(struct xarray *xa, unsigned long index, |
613 | void *entry, gfp_t gfp) |
614 | { |
615 | void *curr; |
616 | |
617 | might_alloc(gfp_mask: gfp); |
618 | xa_lock_irq(xa); |
619 | curr = __xa_store(xa, index, entry, gfp); |
620 | xa_unlock_irq(xa); |
621 | |
622 | return curr; |
623 | } |
624 | |
625 | /** |
626 | * xa_erase_bh() - Erase this entry from the XArray. |
627 | * @xa: XArray. |
628 | * @index: Index of entry. |
629 | * |
630 | * After this function returns, loading from @index will return %NULL. |
631 | * If the index is part of a multi-index entry, all indices will be erased |
632 | * and none of the entries will be part of a multi-index entry. |
633 | * |
634 | * Context: Any context. Takes and releases the xa_lock while |
635 | * disabling softirqs. |
636 | * Return: The entry which used to be at this index. |
637 | */ |
638 | static inline void *xa_erase_bh(struct xarray *xa, unsigned long index) |
639 | { |
640 | void *entry; |
641 | |
642 | xa_lock_bh(xa); |
643 | entry = __xa_erase(xa, index); |
644 | xa_unlock_bh(xa); |
645 | |
646 | return entry; |
647 | } |
648 | |
649 | /** |
650 | * xa_erase_irq() - Erase this entry from the XArray. |
651 | * @xa: XArray. |
652 | * @index: Index of entry. |
653 | * |
654 | * After this function returns, loading from @index will return %NULL. |
655 | * If the index is part of a multi-index entry, all indices will be erased |
656 | * and none of the entries will be part of a multi-index entry. |
657 | * |
658 | * Context: Process context. Takes and releases the xa_lock while |
659 | * disabling interrupts. |
660 | * Return: The entry which used to be at this index. |
661 | */ |
662 | static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) |
663 | { |
664 | void *entry; |
665 | |
666 | xa_lock_irq(xa); |
667 | entry = __xa_erase(xa, index); |
668 | xa_unlock_irq(xa); |
669 | |
670 | return entry; |
671 | } |
672 | |
673 | /** |
674 | * xa_cmpxchg() - Conditionally replace an entry in the XArray. |
675 | * @xa: XArray. |
676 | * @index: Index into array. |
677 | * @old: Old value to test against. |
678 | * @entry: New value to place in array. |
679 | * @gfp: Memory allocation flags. |
680 | * |
681 | * If the entry at @index is the same as @old, replace it with @entry. |
682 | * If the return value is equal to @old, then the exchange was successful. |
683 | * |
684 | * Context: Any context. Takes and releases the xa_lock. May sleep |
685 | * if the @gfp flags permit. |
686 | * Return: The old value at this index or xa_err() if an error happened. |
687 | */ |
688 | static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index, |
689 | void *old, void *entry, gfp_t gfp) |
690 | { |
691 | void *curr; |
692 | |
693 | might_alloc(gfp_mask: gfp); |
694 | xa_lock(xa); |
695 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
696 | xa_unlock(xa); |
697 | |
698 | return curr; |
699 | } |
700 | |
701 | /** |
702 | * xa_cmpxchg_bh() - Conditionally replace an entry in the XArray. |
703 | * @xa: XArray. |
704 | * @index: Index into array. |
705 | * @old: Old value to test against. |
706 | * @entry: New value to place in array. |
707 | * @gfp: Memory allocation flags. |
708 | * |
709 | * This function is like calling xa_cmpxchg() except it disables softirqs |
710 | * while holding the array lock. |
711 | * |
712 | * Context: Any context. Takes and releases the xa_lock while |
713 | * disabling softirqs. May sleep if the @gfp flags permit. |
714 | * Return: The old value at this index or xa_err() if an error happened. |
715 | */ |
716 | static inline void *xa_cmpxchg_bh(struct xarray *xa, unsigned long index, |
717 | void *old, void *entry, gfp_t gfp) |
718 | { |
719 | void *curr; |
720 | |
721 | might_alloc(gfp_mask: gfp); |
722 | xa_lock_bh(xa); |
723 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
724 | xa_unlock_bh(xa); |
725 | |
726 | return curr; |
727 | } |
728 | |
729 | /** |
730 | * xa_cmpxchg_irq() - Conditionally replace an entry in the XArray. |
731 | * @xa: XArray. |
732 | * @index: Index into array. |
733 | * @old: Old value to test against. |
734 | * @entry: New value to place in array. |
735 | * @gfp: Memory allocation flags. |
736 | * |
737 | * This function is like calling xa_cmpxchg() except it disables interrupts |
738 | * while holding the array lock. |
739 | * |
740 | * Context: Process context. Takes and releases the xa_lock while |
741 | * disabling interrupts. May sleep if the @gfp flags permit. |
742 | * Return: The old value at this index or xa_err() if an error happened. |
743 | */ |
744 | static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, |
745 | void *old, void *entry, gfp_t gfp) |
746 | { |
747 | void *curr; |
748 | |
749 | might_alloc(gfp_mask: gfp); |
750 | xa_lock_irq(xa); |
751 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
752 | xa_unlock_irq(xa); |
753 | |
754 | return curr; |
755 | } |
756 | |
757 | /** |
758 | * xa_insert() - Store this entry in the XArray unless another entry is |
759 | * already present. |
760 | * @xa: XArray. |
761 | * @index: Index into array. |
762 | * @entry: New entry. |
763 | * @gfp: Memory allocation flags. |
764 | * |
765 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
766 | * if no entry is present. Inserting will fail if a reserved entry is |
767 | * present, even though loading from this index will return NULL. |
768 | * |
769 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
770 | * the @gfp flags permit. |
771 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
772 | * -ENOMEM if memory could not be allocated. |
773 | */ |
774 | static inline int __must_check xa_insert(struct xarray *xa, |
775 | unsigned long index, void *entry, gfp_t gfp) |
776 | { |
777 | int err; |
778 | |
779 | might_alloc(gfp_mask: gfp); |
780 | xa_lock(xa); |
781 | err = __xa_insert(xa, index, entry, gfp); |
782 | xa_unlock(xa); |
783 | |
784 | return err; |
785 | } |
786 | |
787 | /** |
788 | * xa_insert_bh() - Store this entry in the XArray unless another entry is |
789 | * already present. |
790 | * @xa: XArray. |
791 | * @index: Index into array. |
792 | * @entry: New entry. |
793 | * @gfp: Memory allocation flags. |
794 | * |
795 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
796 | * if no entry is present. Inserting will fail if a reserved entry is |
797 | * present, even though loading from this index will return NULL. |
798 | * |
799 | * Context: Any context. Takes and releases the xa_lock while |
800 | * disabling softirqs. May sleep if the @gfp flags permit. |
801 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
802 | * -ENOMEM if memory could not be allocated. |
803 | */ |
804 | static inline int __must_check xa_insert_bh(struct xarray *xa, |
805 | unsigned long index, void *entry, gfp_t gfp) |
806 | { |
807 | int err; |
808 | |
809 | might_alloc(gfp_mask: gfp); |
810 | xa_lock_bh(xa); |
811 | err = __xa_insert(xa, index, entry, gfp); |
812 | xa_unlock_bh(xa); |
813 | |
814 | return err; |
815 | } |
816 | |
817 | /** |
818 | * xa_insert_irq() - Store this entry in the XArray unless another entry is |
819 | * already present. |
820 | * @xa: XArray. |
821 | * @index: Index into array. |
822 | * @entry: New entry. |
823 | * @gfp: Memory allocation flags. |
824 | * |
825 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
826 | * if no entry is present. Inserting will fail if a reserved entry is |
827 | * present, even though loading from this index will return NULL. |
828 | * |
829 | * Context: Process context. Takes and releases the xa_lock while |
830 | * disabling interrupts. May sleep if the @gfp flags permit. |
831 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
832 | * -ENOMEM if memory could not be allocated. |
833 | */ |
834 | static inline int __must_check xa_insert_irq(struct xarray *xa, |
835 | unsigned long index, void *entry, gfp_t gfp) |
836 | { |
837 | int err; |
838 | |
839 | might_alloc(gfp_mask: gfp); |
840 | xa_lock_irq(xa); |
841 | err = __xa_insert(xa, index, entry, gfp); |
842 | xa_unlock_irq(xa); |
843 | |
844 | return err; |
845 | } |
846 | |
847 | /** |
848 | * xa_alloc() - Find somewhere to store this entry in the XArray. |
849 | * @xa: XArray. |
850 | * @id: Pointer to ID. |
851 | * @entry: New entry. |
852 | * @limit: Range of ID to allocate. |
853 | * @gfp: Memory allocation flags. |
854 | * |
855 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
856 | * stores the index into the @id pointer, then stores the entry at |
857 | * that index. A concurrent lookup will not see an uninitialised @id. |
858 | * |
859 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
860 | * in xa_init_flags(). |
861 | * |
862 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
863 | * the @gfp flags permit. |
864 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
865 | * -EBUSY if there are no free entries in @limit. |
866 | */ |
867 | static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, |
868 | void *entry, struct xa_limit limit, gfp_t gfp) |
869 | { |
870 | int err; |
871 | |
872 | might_alloc(gfp_mask: gfp); |
873 | xa_lock(xa); |
874 | err = __xa_alloc(xa, id, entry, limit, gfp); |
875 | xa_unlock(xa); |
876 | |
877 | return err; |
878 | } |
879 | |
880 | /** |
881 | * xa_alloc_bh() - Find somewhere to store this entry in the XArray. |
882 | * @xa: XArray. |
883 | * @id: Pointer to ID. |
884 | * @entry: New entry. |
885 | * @limit: Range of ID to allocate. |
886 | * @gfp: Memory allocation flags. |
887 | * |
888 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
889 | * stores the index into the @id pointer, then stores the entry at |
890 | * that index. A concurrent lookup will not see an uninitialised @id. |
891 | * |
892 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
893 | * in xa_init_flags(). |
894 | * |
895 | * Context: Any context. Takes and releases the xa_lock while |
896 | * disabling softirqs. May sleep if the @gfp flags permit. |
897 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
898 | * -EBUSY if there are no free entries in @limit. |
899 | */ |
900 | static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, |
901 | void *entry, struct xa_limit limit, gfp_t gfp) |
902 | { |
903 | int err; |
904 | |
905 | might_alloc(gfp_mask: gfp); |
906 | xa_lock_bh(xa); |
907 | err = __xa_alloc(xa, id, entry, limit, gfp); |
908 | xa_unlock_bh(xa); |
909 | |
910 | return err; |
911 | } |
912 | |
913 | /** |
914 | * xa_alloc_irq() - Find somewhere to store this entry in the XArray. |
915 | * @xa: XArray. |
916 | * @id: Pointer to ID. |
917 | * @entry: New entry. |
918 | * @limit: Range of ID to allocate. |
919 | * @gfp: Memory allocation flags. |
920 | * |
921 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
922 | * stores the index into the @id pointer, then stores the entry at |
923 | * that index. A concurrent lookup will not see an uninitialised @id. |
924 | * |
925 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
926 | * in xa_init_flags(). |
927 | * |
928 | * Context: Process context. Takes and releases the xa_lock while |
929 | * disabling interrupts. May sleep if the @gfp flags permit. |
930 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
931 | * -EBUSY if there are no free entries in @limit. |
932 | */ |
933 | static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, |
934 | void *entry, struct xa_limit limit, gfp_t gfp) |
935 | { |
936 | int err; |
937 | |
938 | might_alloc(gfp_mask: gfp); |
939 | xa_lock_irq(xa); |
940 | err = __xa_alloc(xa, id, entry, limit, gfp); |
941 | xa_unlock_irq(xa); |
942 | |
943 | return err; |
944 | } |
945 | |
946 | /** |
947 | * xa_alloc_cyclic() - Find somewhere to store this entry in the XArray. |
948 | * @xa: XArray. |
949 | * @id: Pointer to ID. |
950 | * @entry: New entry. |
951 | * @limit: Range of allocated ID. |
952 | * @next: Pointer to next ID to allocate. |
953 | * @gfp: Memory allocation flags. |
954 | * |
955 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
956 | * stores the index into the @id pointer, then stores the entry at |
957 | * that index. A concurrent lookup will not see an uninitialised @id. |
958 | * The search for an empty entry will start at @next and will wrap |
959 | * around if necessary. |
960 | * |
961 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
962 | * in xa_init_flags(). |
963 | * |
964 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
965 | * the @gfp flags permit. |
966 | * Return: 0 if the allocation succeeded without wrapping. 1 if the |
967 | * allocation succeeded after wrapping, -ENOMEM if memory could not be |
968 | * allocated or -EBUSY if there are no free entries in @limit. |
969 | */ |
970 | static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, |
971 | struct xa_limit limit, u32 *next, gfp_t gfp) |
972 | { |
973 | int err; |
974 | |
975 | might_alloc(gfp_mask: gfp); |
976 | xa_lock(xa); |
977 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
978 | xa_unlock(xa); |
979 | |
980 | return err; |
981 | } |
982 | |
983 | /** |
984 | * xa_alloc_cyclic_bh() - Find somewhere to store this entry in the XArray. |
985 | * @xa: XArray. |
986 | * @id: Pointer to ID. |
987 | * @entry: New entry. |
988 | * @limit: Range of allocated ID. |
989 | * @next: Pointer to next ID to allocate. |
990 | * @gfp: Memory allocation flags. |
991 | * |
992 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
993 | * stores the index into the @id pointer, then stores the entry at |
994 | * that index. A concurrent lookup will not see an uninitialised @id. |
995 | * The search for an empty entry will start at @next and will wrap |
996 | * around if necessary. |
997 | * |
998 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
999 | * in xa_init_flags(). |
1000 | * |
1001 | * Context: Any context. Takes and releases the xa_lock while |
1002 | * disabling softirqs. May sleep if the @gfp flags permit. |
1003 | * Return: 0 if the allocation succeeded without wrapping. 1 if the |
1004 | * allocation succeeded after wrapping, -ENOMEM if memory could not be |
1005 | * allocated or -EBUSY if there are no free entries in @limit. |
1006 | */ |
1007 | static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, |
1008 | struct xa_limit limit, u32 *next, gfp_t gfp) |
1009 | { |
1010 | int err; |
1011 | |
1012 | might_alloc(gfp_mask: gfp); |
1013 | xa_lock_bh(xa); |
1014 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
1015 | xa_unlock_bh(xa); |
1016 | |
1017 | return err; |
1018 | } |
1019 | |
1020 | /** |
1021 | * xa_alloc_cyclic_irq() - Find somewhere to store this entry in the XArray. |
1022 | * @xa: XArray. |
1023 | * @id: Pointer to ID. |
1024 | * @entry: New entry. |
1025 | * @limit: Range of allocated ID. |
1026 | * @next: Pointer to next ID to allocate. |
1027 | * @gfp: Memory allocation flags. |
1028 | * |
1029 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
1030 | * stores the index into the @id pointer, then stores the entry at |
1031 | * that index. A concurrent lookup will not see an uninitialised @id. |
1032 | * The search for an empty entry will start at @next and will wrap |
1033 | * around if necessary. |
1034 | * |
1035 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
1036 | * in xa_init_flags(). |
1037 | * |
1038 | * Context: Process context. Takes and releases the xa_lock while |
1039 | * disabling interrupts. May sleep if the @gfp flags permit. |
1040 | * Return: 0 if the allocation succeeded without wrapping. 1 if the |
1041 | * allocation succeeded after wrapping, -ENOMEM if memory could not be |
1042 | * allocated or -EBUSY if there are no free entries in @limit. |
1043 | */ |
1044 | static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry, |
1045 | struct xa_limit limit, u32 *next, gfp_t gfp) |
1046 | { |
1047 | int err; |
1048 | |
1049 | might_alloc(gfp_mask: gfp); |
1050 | xa_lock_irq(xa); |
1051 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
1052 | xa_unlock_irq(xa); |
1053 | |
1054 | return err; |
1055 | } |
1056 | |
1057 | /** |
1058 | * xa_reserve() - Reserve this index in the XArray. |
1059 | * @xa: XArray. |
1060 | * @index: Index into array. |
1061 | * @gfp: Memory allocation flags. |
1062 | * |
1063 | * Ensures there is somewhere to store an entry at @index in the array. |
1064 | * If there is already something stored at @index, this function does |
1065 | * nothing. If there was nothing there, the entry is marked as reserved. |
1066 | * Loading from a reserved entry returns a %NULL pointer. |
1067 | * |
1068 | * If you do not use the entry that you have reserved, call xa_release() |
1069 | * or xa_erase() to free any unnecessary memory. |
1070 | * |
1071 | * Context: Any context. Takes and releases the xa_lock. |
1072 | * May sleep if the @gfp flags permit. |
1073 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
1074 | */ |
1075 | static inline __must_check |
1076 | int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) |
1077 | { |
1078 | return xa_err(entry: xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
1079 | } |
1080 | |
1081 | /** |
1082 | * xa_reserve_bh() - Reserve this index in the XArray. |
1083 | * @xa: XArray. |
1084 | * @index: Index into array. |
1085 | * @gfp: Memory allocation flags. |
1086 | * |
1087 | * A softirq-disabling version of xa_reserve(). |
1088 | * |
1089 | * Context: Any context. Takes and releases the xa_lock while |
1090 | * disabling softirqs. |
1091 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
1092 | */ |
1093 | static inline __must_check |
1094 | int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp) |
1095 | { |
1096 | return xa_err(entry: xa_cmpxchg_bh(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
1097 | } |
1098 | |
1099 | /** |
1100 | * xa_reserve_irq() - Reserve this index in the XArray. |
1101 | * @xa: XArray. |
1102 | * @index: Index into array. |
1103 | * @gfp: Memory allocation flags. |
1104 | * |
1105 | * An interrupt-disabling version of xa_reserve(). |
1106 | * |
1107 | * Context: Process context. Takes and releases the xa_lock while |
1108 | * disabling interrupts. |
1109 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
1110 | */ |
1111 | static inline __must_check |
1112 | int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) |
1113 | { |
1114 | return xa_err(entry: xa_cmpxchg_irq(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
1115 | } |
1116 | |
1117 | /** |
1118 | * xa_release() - Release a reserved entry. |
1119 | * @xa: XArray. |
1120 | * @index: Index of entry. |
1121 | * |
1122 | * After calling xa_reserve(), you can call this function to release the |
1123 | * reservation. If the entry at @index has been stored to, this function |
1124 | * will do nothing. |
1125 | */ |
1126 | static inline void xa_release(struct xarray *xa, unsigned long index) |
1127 | { |
1128 | xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, gfp: 0); |
1129 | } |
1130 | |
1131 | /* Everything below here is the Advanced API. Proceed with caution. */ |
1132 | |
1133 | /* |
1134 | * The xarray is constructed out of a set of 'chunks' of pointers. Choosing |
1135 | * the best chunk size requires some tradeoffs. A power of two recommends |
1136 | * itself so that we can walk the tree based purely on shifts and masks. |
1137 | * Generally, the larger the better; as the number of slots per level of the |
1138 | * tree increases, the less tall the tree needs to be. But that needs to be |
1139 | * balanced against the memory consumption of each node. On a 64-bit system, |
1140 | * xa_node is currently 576 bytes, and we get 7 of them per 4kB page. If we |
1141 | * doubled the number of slots per node, we'd get only 3 nodes per 4kB page. |
1142 | */ |
1143 | #ifndef XA_CHUNK_SHIFT |
1144 | #define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
1145 | #endif |
1146 | #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) |
1147 | #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) |
1148 | #define XA_MAX_MARKS 3 |
1149 | #define XA_MARK_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG) |
1150 | |
1151 | /* |
1152 | * @count is the count of every non-NULL element in the ->slots array |
1153 | * whether that is a value entry, a retry entry, a user pointer, |
1154 | * a sibling entry or a pointer to the next level of the tree. |
1155 | * @nr_values is the count of every element in ->slots which is |
1156 | * either a value entry or a sibling of a value entry. |
1157 | */ |
1158 | struct xa_node { |
1159 | unsigned char shift; /* Bits remaining in each slot */ |
1160 | unsigned char offset; /* Slot offset in parent */ |
1161 | unsigned char count; /* Total entry count */ |
1162 | unsigned char nr_values; /* Value entry count */ |
1163 | struct xa_node __rcu *parent; /* NULL at top of tree */ |
1164 | struct xarray *array; /* The array we belong to */ |
1165 | union { |
1166 | struct list_head private_list; /* For tree user */ |
1167 | struct rcu_head rcu_head; /* Used when freeing node */ |
1168 | }; |
1169 | void __rcu *slots[XA_CHUNK_SIZE]; |
1170 | union { |
1171 | unsigned long tags[XA_MAX_MARKS][XA_MARK_LONGS]; |
1172 | unsigned long marks[XA_MAX_MARKS][XA_MARK_LONGS]; |
1173 | }; |
1174 | }; |
1175 | |
1176 | void xa_dump(const struct xarray *); |
1177 | void xa_dump_node(const struct xa_node *); |
1178 | |
1179 | #ifdef XA_DEBUG |
1180 | #define XA_BUG_ON(xa, x) do { \ |
1181 | if (x) { \ |
1182 | xa_dump(xa); \ |
1183 | BUG(); \ |
1184 | } \ |
1185 | } while (0) |
1186 | #define XA_NODE_BUG_ON(node, x) do { \ |
1187 | if (x) { \ |
1188 | if (node) xa_dump_node(node); \ |
1189 | BUG(); \ |
1190 | } \ |
1191 | } while (0) |
1192 | #else |
1193 | #define XA_BUG_ON(xa, x) do { } while (0) |
1194 | #define XA_NODE_BUG_ON(node, x) do { } while (0) |
1195 | #endif |
1196 | |
1197 | /* Private */ |
1198 | static inline void *xa_head(const struct xarray *xa) |
1199 | { |
1200 | return rcu_dereference_check(xa->xa_head, |
1201 | lockdep_is_held(&xa->xa_lock)); |
1202 | } |
1203 | |
1204 | /* Private */ |
1205 | static inline void *xa_head_locked(const struct xarray *xa) |
1206 | { |
1207 | return rcu_dereference_protected(xa->xa_head, |
1208 | lockdep_is_held(&xa->xa_lock)); |
1209 | } |
1210 | |
1211 | /* Private */ |
1212 | static inline void *xa_entry(const struct xarray *xa, |
1213 | const struct xa_node *node, unsigned int offset) |
1214 | { |
1215 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); |
1216 | return rcu_dereference_check(node->slots[offset], |
1217 | lockdep_is_held(&xa->xa_lock)); |
1218 | } |
1219 | |
1220 | /* Private */ |
1221 | static inline void *xa_entry_locked(const struct xarray *xa, |
1222 | const struct xa_node *node, unsigned int offset) |
1223 | { |
1224 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); |
1225 | return rcu_dereference_protected(node->slots[offset], |
1226 | lockdep_is_held(&xa->xa_lock)); |
1227 | } |
1228 | |
1229 | /* Private */ |
1230 | static inline struct xa_node *xa_parent(const struct xarray *xa, |
1231 | const struct xa_node *node) |
1232 | { |
1233 | return rcu_dereference_check(node->parent, |
1234 | lockdep_is_held(&xa->xa_lock)); |
1235 | } |
1236 | |
1237 | /* Private */ |
1238 | static inline struct xa_node *xa_parent_locked(const struct xarray *xa, |
1239 | const struct xa_node *node) |
1240 | { |
1241 | return rcu_dereference_protected(node->parent, |
1242 | lockdep_is_held(&xa->xa_lock)); |
1243 | } |
1244 | |
1245 | /* Private */ |
1246 | static inline void *xa_mk_node(const struct xa_node *node) |
1247 | { |
1248 | return (void *)((unsigned long)node | 2); |
1249 | } |
1250 | |
1251 | /* Private */ |
1252 | static inline struct xa_node *xa_to_node(const void *entry) |
1253 | { |
1254 | return (struct xa_node *)((unsigned long)entry - 2); |
1255 | } |
1256 | |
1257 | /* Private */ |
1258 | static inline bool xa_is_node(const void *entry) |
1259 | { |
1260 | return xa_is_internal(entry) && (unsigned long)entry > 4096; |
1261 | } |
1262 | |
1263 | /* Private */ |
1264 | static inline void *xa_mk_sibling(unsigned int offset) |
1265 | { |
1266 | return xa_mk_internal(v: offset); |
1267 | } |
1268 | |
1269 | /* Private */ |
1270 | static inline unsigned long xa_to_sibling(const void *entry) |
1271 | { |
1272 | return xa_to_internal(entry); |
1273 | } |
1274 | |
1275 | /** |
1276 | * xa_is_sibling() - Is the entry a sibling entry? |
1277 | * @entry: Entry retrieved from the XArray |
1278 | * |
1279 | * Return: %true if the entry is a sibling entry. |
1280 | */ |
1281 | static inline bool xa_is_sibling(const void *entry) |
1282 | { |
1283 | return IS_ENABLED(CONFIG_XARRAY_MULTI) && xa_is_internal(entry) && |
1284 | (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1)); |
1285 | } |
1286 | |
1287 | #define XA_RETRY_ENTRY xa_mk_internal(256) |
1288 | |
1289 | /** |
1290 | * xa_is_retry() - Is the entry a retry entry? |
1291 | * @entry: Entry retrieved from the XArray |
1292 | * |
1293 | * Return: %true if the entry is a retry entry. |
1294 | */ |
1295 | static inline bool xa_is_retry(const void *entry) |
1296 | { |
1297 | return unlikely(entry == XA_RETRY_ENTRY); |
1298 | } |
1299 | |
1300 | /** |
1301 | * xa_is_advanced() - Is the entry only permitted for the advanced API? |
1302 | * @entry: Entry to be stored in the XArray. |
1303 | * |
1304 | * Return: %true if the entry cannot be stored by the normal API. |
1305 | */ |
1306 | static inline bool xa_is_advanced(const void *entry) |
1307 | { |
1308 | return xa_is_internal(entry) && (entry <= XA_RETRY_ENTRY); |
1309 | } |
1310 | |
1311 | /** |
1312 | * typedef xa_update_node_t - A callback function from the XArray. |
1313 | * @node: The node which is being processed |
1314 | * |
1315 | * This function is called every time the XArray updates the count of |
1316 | * present and value entries in a node. It allows advanced users to |
1317 | * maintain the private_list in the node. |
1318 | * |
1319 | * Context: The xa_lock is held and interrupts may be disabled. |
1320 | * Implementations should not drop the xa_lock, nor re-enable |
1321 | * interrupts. |
1322 | */ |
1323 | typedef void (*xa_update_node_t)(struct xa_node *node); |
1324 | |
1325 | void xa_delete_node(struct xa_node *, xa_update_node_t); |
1326 | |
1327 | /* |
1328 | * The xa_state is opaque to its users. It contains various different pieces |
1329 | * of state involved in the current operation on the XArray. It should be |
1330 | * declared on the stack and passed between the various internal routines. |
1331 | * The various elements in it should not be accessed directly, but only |
1332 | * through the provided accessor functions. The below documentation is for |
1333 | * the benefit of those working on the code, not for users of the XArray. |
1334 | * |
1335 | * @xa_node usually points to the xa_node containing the slot we're operating |
1336 | * on (and @xa_offset is the offset in the slots array). If there is a |
1337 | * single entry in the array at index 0, there are no allocated xa_nodes to |
1338 | * point to, and so we store %NULL in @xa_node. @xa_node is set to |
1339 | * the value %XAS_RESTART if the xa_state is not walked to the correct |
1340 | * position in the tree of nodes for this operation. If an error occurs |
1341 | * during an operation, it is set to an %XAS_ERROR value. If we run off the |
1342 | * end of the allocated nodes, it is set to %XAS_BOUNDS. |
1343 | */ |
1344 | struct xa_state { |
1345 | struct xarray *xa; |
1346 | unsigned long xa_index; |
1347 | unsigned char xa_shift; |
1348 | unsigned char xa_sibs; |
1349 | unsigned char xa_offset; |
1350 | unsigned char xa_pad; /* Helps gcc generate better code */ |
1351 | struct xa_node *xa_node; |
1352 | struct xa_node *xa_alloc; |
1353 | xa_update_node_t xa_update; |
1354 | struct list_lru *xa_lru; |
1355 | }; |
1356 | |
1357 | /* |
1358 | * We encode errnos in the xas->xa_node. If an error has happened, we need to |
1359 | * drop the lock to fix it, and once we've done so the xa_state is invalid. |
1360 | */ |
1361 | #define XA_ERROR(errno) ((struct xa_node *)(((unsigned long)errno << 2) | 2UL)) |
1362 | #define XAS_BOUNDS ((struct xa_node *)1UL) |
1363 | #define XAS_RESTART ((struct xa_node *)3UL) |
1364 | |
1365 | #define __XA_STATE(array, index, shift, sibs) { \ |
1366 | .xa = array, \ |
1367 | .xa_index = index, \ |
1368 | .xa_shift = shift, \ |
1369 | .xa_sibs = sibs, \ |
1370 | .xa_offset = 0, \ |
1371 | .xa_pad = 0, \ |
1372 | .xa_node = XAS_RESTART, \ |
1373 | .xa_alloc = NULL, \ |
1374 | .xa_update = NULL, \ |
1375 | .xa_lru = NULL, \ |
1376 | } |
1377 | |
1378 | /** |
1379 | * XA_STATE() - Declare an XArray operation state. |
1380 | * @name: Name of this operation state (usually xas). |
1381 | * @array: Array to operate on. |
1382 | * @index: Initial index of interest. |
1383 | * |
1384 | * Declare and initialise an xa_state on the stack. |
1385 | */ |
1386 | #define XA_STATE(name, array, index) \ |
1387 | struct xa_state name = __XA_STATE(array, index, 0, 0) |
1388 | |
1389 | /** |
1390 | * XA_STATE_ORDER() - Declare an XArray operation state. |
1391 | * @name: Name of this operation state (usually xas). |
1392 | * @array: Array to operate on. |
1393 | * @index: Initial index of interest. |
1394 | * @order: Order of entry. |
1395 | * |
1396 | * Declare and initialise an xa_state on the stack. This variant of |
1397 | * XA_STATE() allows you to specify the 'order' of the element you |
1398 | * want to operate on.` |
1399 | */ |
1400 | #define XA_STATE_ORDER(name, array, index, order) \ |
1401 | struct xa_state name = __XA_STATE(array, \ |
1402 | (index >> order) << order, \ |
1403 | order - (order % XA_CHUNK_SHIFT), \ |
1404 | (1U << (order % XA_CHUNK_SHIFT)) - 1) |
1405 | |
1406 | #define xas_marked(xas, mark) xa_marked((xas)->xa, (mark)) |
1407 | #define xas_trylock(xas) xa_trylock((xas)->xa) |
1408 | #define xas_lock(xas) xa_lock((xas)->xa) |
1409 | #define xas_unlock(xas) xa_unlock((xas)->xa) |
1410 | #define xas_lock_bh(xas) xa_lock_bh((xas)->xa) |
1411 | #define xas_unlock_bh(xas) xa_unlock_bh((xas)->xa) |
1412 | #define xas_lock_irq(xas) xa_lock_irq((xas)->xa) |
1413 | #define xas_unlock_irq(xas) xa_unlock_irq((xas)->xa) |
1414 | #define xas_lock_irqsave(xas, flags) \ |
1415 | xa_lock_irqsave((xas)->xa, flags) |
1416 | #define xas_unlock_irqrestore(xas, flags) \ |
1417 | xa_unlock_irqrestore((xas)->xa, flags) |
1418 | |
1419 | /** |
1420 | * xas_error() - Return an errno stored in the xa_state. |
1421 | * @xas: XArray operation state. |
1422 | * |
1423 | * Return: 0 if no error has been noted. A negative errno if one has. |
1424 | */ |
1425 | static inline int xas_error(const struct xa_state *xas) |
1426 | { |
1427 | return xa_err(entry: xas->xa_node); |
1428 | } |
1429 | |
1430 | /** |
1431 | * xas_set_err() - Note an error in the xa_state. |
1432 | * @xas: XArray operation state. |
1433 | * @err: Negative error number. |
1434 | * |
1435 | * Only call this function with a negative @err; zero or positive errors |
1436 | * will probably not behave the way you think they should. If you want |
1437 | * to clear the error from an xa_state, use xas_reset(). |
1438 | */ |
1439 | static inline void xas_set_err(struct xa_state *xas, long err) |
1440 | { |
1441 | xas->xa_node = XA_ERROR(err); |
1442 | } |
1443 | |
1444 | /** |
1445 | * xas_invalid() - Is the xas in a retry or error state? |
1446 | * @xas: XArray operation state. |
1447 | * |
1448 | * Return: %true if the xas cannot be used for operations. |
1449 | */ |
1450 | static inline bool xas_invalid(const struct xa_state *xas) |
1451 | { |
1452 | return (unsigned long)xas->xa_node & 3; |
1453 | } |
1454 | |
1455 | /** |
1456 | * xas_valid() - Is the xas a valid cursor into the array? |
1457 | * @xas: XArray operation state. |
1458 | * |
1459 | * Return: %true if the xas can be used for operations. |
1460 | */ |
1461 | static inline bool xas_valid(const struct xa_state *xas) |
1462 | { |
1463 | return !xas_invalid(xas); |
1464 | } |
1465 | |
1466 | /** |
1467 | * xas_is_node() - Does the xas point to a node? |
1468 | * @xas: XArray operation state. |
1469 | * |
1470 | * Return: %true if the xas currently references a node. |
1471 | */ |
1472 | static inline bool xas_is_node(const struct xa_state *xas) |
1473 | { |
1474 | return xas_valid(xas) && xas->xa_node; |
1475 | } |
1476 | |
1477 | /* True if the pointer is something other than a node */ |
1478 | static inline bool xas_not_node(struct xa_node *node) |
1479 | { |
1480 | return ((unsigned long)node & 3) || !node; |
1481 | } |
1482 | |
1483 | /* True if the node represents RESTART or an error */ |
1484 | static inline bool xas_frozen(struct xa_node *node) |
1485 | { |
1486 | return (unsigned long)node & 2; |
1487 | } |
1488 | |
1489 | /* True if the node represents head-of-tree, RESTART or BOUNDS */ |
1490 | static inline bool xas_top(struct xa_node *node) |
1491 | { |
1492 | return node <= XAS_RESTART; |
1493 | } |
1494 | |
1495 | /** |
1496 | * xas_reset() - Reset an XArray operation state. |
1497 | * @xas: XArray operation state. |
1498 | * |
1499 | * Resets the error or walk state of the @xas so future walks of the |
1500 | * array will start from the root. Use this if you have dropped the |
1501 | * xarray lock and want to reuse the xa_state. |
1502 | * |
1503 | * Context: Any context. |
1504 | */ |
1505 | static inline void xas_reset(struct xa_state *xas) |
1506 | { |
1507 | xas->xa_node = XAS_RESTART; |
1508 | } |
1509 | |
1510 | /** |
1511 | * xas_retry() - Retry the operation if appropriate. |
1512 | * @xas: XArray operation state. |
1513 | * @entry: Entry from xarray. |
1514 | * |
1515 | * The advanced functions may sometimes return an internal entry, such as |
1516 | * a retry entry or a zero entry. This function sets up the @xas to restart |
1517 | * the walk from the head of the array if needed. |
1518 | * |
1519 | * Context: Any context. |
1520 | * Return: true if the operation needs to be retried. |
1521 | */ |
1522 | static inline bool xas_retry(struct xa_state *xas, const void *entry) |
1523 | { |
1524 | if (xa_is_zero(entry)) |
1525 | return true; |
1526 | if (!xa_is_retry(entry)) |
1527 | return false; |
1528 | xas_reset(xas); |
1529 | return true; |
1530 | } |
1531 | |
1532 | void *xas_load(struct xa_state *); |
1533 | void *xas_store(struct xa_state *, void *entry); |
1534 | void *xas_find(struct xa_state *, unsigned long max); |
1535 | void *xas_find_conflict(struct xa_state *); |
1536 | |
1537 | bool xas_get_mark(const struct xa_state *, xa_mark_t); |
1538 | void xas_set_mark(const struct xa_state *, xa_mark_t); |
1539 | void xas_clear_mark(const struct xa_state *, xa_mark_t); |
1540 | void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t); |
1541 | void xas_init_marks(const struct xa_state *); |
1542 | |
1543 | bool xas_nomem(struct xa_state *, gfp_t); |
1544 | void xas_destroy(struct xa_state *); |
1545 | void xas_pause(struct xa_state *); |
1546 | |
1547 | void xas_create_range(struct xa_state *); |
1548 | |
1549 | #ifdef CONFIG_XARRAY_MULTI |
1550 | int xa_get_order(struct xarray *, unsigned long index); |
1551 | void xas_split(struct xa_state *, void *entry, unsigned int order); |
1552 | void xas_split_alloc(struct xa_state *, void *entry, unsigned int order, gfp_t); |
1553 | #else |
1554 | static inline int xa_get_order(struct xarray *xa, unsigned long index) |
1555 | { |
1556 | return 0; |
1557 | } |
1558 | |
1559 | static inline void xas_split(struct xa_state *xas, void *entry, |
1560 | unsigned int order) |
1561 | { |
1562 | xas_store(xas, entry); |
1563 | } |
1564 | |
1565 | static inline void xas_split_alloc(struct xa_state *xas, void *entry, |
1566 | unsigned int order, gfp_t gfp) |
1567 | { |
1568 | } |
1569 | #endif |
1570 | |
1571 | /** |
1572 | * xas_reload() - Refetch an entry from the xarray. |
1573 | * @xas: XArray operation state. |
1574 | * |
1575 | * Use this function to check that a previously loaded entry still has |
1576 | * the same value. This is useful for the lockless pagecache lookup where |
1577 | * we walk the array with only the RCU lock to protect us, lock the page, |
1578 | * then check that the page hasn't moved since we looked it up. |
1579 | * |
1580 | * The caller guarantees that @xas is still valid. If it may be in an |
1581 | * error or restart state, call xas_load() instead. |
1582 | * |
1583 | * Return: The entry at this location in the xarray. |
1584 | */ |
1585 | static inline void *xas_reload(struct xa_state *xas) |
1586 | { |
1587 | struct xa_node *node = xas->xa_node; |
1588 | void *entry; |
1589 | char offset; |
1590 | |
1591 | if (!node) |
1592 | return xa_head(xa: xas->xa); |
1593 | if (IS_ENABLED(CONFIG_XARRAY_MULTI)) { |
1594 | offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK; |
1595 | entry = xa_entry(xa: xas->xa, node, offset); |
1596 | if (!xa_is_sibling(entry)) |
1597 | return entry; |
1598 | offset = xa_to_sibling(entry); |
1599 | } else { |
1600 | offset = xas->xa_offset; |
1601 | } |
1602 | return xa_entry(xa: xas->xa, node, offset); |
1603 | } |
1604 | |
1605 | /** |
1606 | * xas_set() - Set up XArray operation state for a different index. |
1607 | * @xas: XArray operation state. |
1608 | * @index: New index into the XArray. |
1609 | * |
1610 | * Move the operation state to refer to a different index. This will |
1611 | * have the effect of starting a walk from the top; see xas_next() |
1612 | * to move to an adjacent index. |
1613 | */ |
1614 | static inline void xas_set(struct xa_state *xas, unsigned long index) |
1615 | { |
1616 | xas->xa_index = index; |
1617 | xas->xa_node = XAS_RESTART; |
1618 | } |
1619 | |
1620 | /** |
1621 | * xas_advance() - Skip over sibling entries. |
1622 | * @xas: XArray operation state. |
1623 | * @index: Index of last sibling entry. |
1624 | * |
1625 | * Move the operation state to refer to the last sibling entry. |
1626 | * This is useful for loops that normally want to see sibling |
1627 | * entries but sometimes want to skip them. Use xas_set() if you |
1628 | * want to move to an index which is not part of this entry. |
1629 | */ |
1630 | static inline void xas_advance(struct xa_state *xas, unsigned long index) |
1631 | { |
1632 | unsigned char shift = xas_is_node(xas) ? xas->xa_node->shift : 0; |
1633 | |
1634 | xas->xa_index = index; |
1635 | xas->xa_offset = (index >> shift) & XA_CHUNK_MASK; |
1636 | } |
1637 | |
1638 | /** |
1639 | * xas_set_order() - Set up XArray operation state for a multislot entry. |
1640 | * @xas: XArray operation state. |
1641 | * @index: Target of the operation. |
1642 | * @order: Entry occupies 2^@order indices. |
1643 | */ |
1644 | static inline void xas_set_order(struct xa_state *xas, unsigned long index, |
1645 | unsigned int order) |
1646 | { |
1647 | #ifdef CONFIG_XARRAY_MULTI |
1648 | xas->xa_index = order < BITS_PER_LONG ? (index >> order) << order : 0; |
1649 | xas->xa_shift = order - (order % XA_CHUNK_SHIFT); |
1650 | xas->xa_sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; |
1651 | xas->xa_node = XAS_RESTART; |
1652 | #else |
1653 | BUG_ON(order > 0); |
1654 | xas_set(xas, index); |
1655 | #endif |
1656 | } |
1657 | |
1658 | /** |
1659 | * xas_set_update() - Set up XArray operation state for a callback. |
1660 | * @xas: XArray operation state. |
1661 | * @update: Function to call when updating a node. |
1662 | * |
1663 | * The XArray can notify a caller after it has updated an xa_node. |
1664 | * This is advanced functionality and is only needed by the page |
1665 | * cache and swap cache. |
1666 | */ |
1667 | static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) |
1668 | { |
1669 | xas->xa_update = update; |
1670 | } |
1671 | |
1672 | static inline void xas_set_lru(struct xa_state *xas, struct list_lru *lru) |
1673 | { |
1674 | xas->xa_lru = lru; |
1675 | } |
1676 | |
1677 | /** |
1678 | * xas_next_entry() - Advance iterator to next present entry. |
1679 | * @xas: XArray operation state. |
1680 | * @max: Highest index to return. |
1681 | * |
1682 | * xas_next_entry() is an inline function to optimise xarray traversal for |
1683 | * speed. It is equivalent to calling xas_find(), and will call xas_find() |
1684 | * for all the hard cases. |
1685 | * |
1686 | * Return: The next present entry after the one currently referred to by @xas. |
1687 | */ |
1688 | static inline void *xas_next_entry(struct xa_state *xas, unsigned long max) |
1689 | { |
1690 | struct xa_node *node = xas->xa_node; |
1691 | void *entry; |
1692 | |
1693 | if (unlikely(xas_not_node(node) || node->shift || |
1694 | xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK))) |
1695 | return xas_find(xas, max); |
1696 | |
1697 | do { |
1698 | if (unlikely(xas->xa_index >= max)) |
1699 | return xas_find(xas, max); |
1700 | if (unlikely(xas->xa_offset == XA_CHUNK_MASK)) |
1701 | return xas_find(xas, max); |
1702 | entry = xa_entry(xa: xas->xa, node, offset: xas->xa_offset + 1); |
1703 | if (unlikely(xa_is_internal(entry))) |
1704 | return xas_find(xas, max); |
1705 | xas->xa_offset++; |
1706 | xas->xa_index++; |
1707 | } while (!entry); |
1708 | |
1709 | return entry; |
1710 | } |
1711 | |
1712 | /* Private */ |
1713 | static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, |
1714 | xa_mark_t mark) |
1715 | { |
1716 | unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark]; |
1717 | unsigned int offset = xas->xa_offset; |
1718 | |
1719 | if (advance) |
1720 | offset++; |
1721 | if (XA_CHUNK_SIZE == BITS_PER_LONG) { |
1722 | if (offset < XA_CHUNK_SIZE) { |
1723 | unsigned long data = *addr & (~0UL << offset); |
1724 | if (data) |
1725 | return __ffs(data); |
1726 | } |
1727 | return XA_CHUNK_SIZE; |
1728 | } |
1729 | |
1730 | return find_next_bit(addr, XA_CHUNK_SIZE, offset); |
1731 | } |
1732 | |
1733 | /** |
1734 | * xas_next_marked() - Advance iterator to next marked entry. |
1735 | * @xas: XArray operation state. |
1736 | * @max: Highest index to return. |
1737 | * @mark: Mark to search for. |
1738 | * |
1739 | * xas_next_marked() is an inline function to optimise xarray traversal for |
1740 | * speed. It is equivalent to calling xas_find_marked(), and will call |
1741 | * xas_find_marked() for all the hard cases. |
1742 | * |
1743 | * Return: The next marked entry after the one currently referred to by @xas. |
1744 | */ |
1745 | static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, |
1746 | xa_mark_t mark) |
1747 | { |
1748 | struct xa_node *node = xas->xa_node; |
1749 | void *entry; |
1750 | unsigned int offset; |
1751 | |
1752 | if (unlikely(xas_not_node(node) || node->shift)) |
1753 | return xas_find_marked(xas, max, mark); |
1754 | offset = xas_find_chunk(xas, advance: true, mark); |
1755 | xas->xa_offset = offset; |
1756 | xas->xa_index = (xas->xa_index & ~XA_CHUNK_MASK) + offset; |
1757 | if (xas->xa_index > max) |
1758 | return NULL; |
1759 | if (offset == XA_CHUNK_SIZE) |
1760 | return xas_find_marked(xas, max, mark); |
1761 | entry = xa_entry(xa: xas->xa, node, offset); |
1762 | if (!entry) |
1763 | return xas_find_marked(xas, max, mark); |
1764 | return entry; |
1765 | } |
1766 | |
1767 | /* |
1768 | * If iterating while holding a lock, drop the lock and reschedule |
1769 | * every %XA_CHECK_SCHED loops. |
1770 | */ |
1771 | enum { |
1772 | XA_CHECK_SCHED = 4096, |
1773 | }; |
1774 | |
1775 | /** |
1776 | * xas_for_each() - Iterate over a range of an XArray. |
1777 | * @xas: XArray operation state. |
1778 | * @entry: Entry retrieved from the array. |
1779 | * @max: Maximum index to retrieve from array. |
1780 | * |
1781 | * The loop body will be executed for each entry present in the xarray |
1782 | * between the current xas position and @max. @entry will be set to |
1783 | * the entry retrieved from the xarray. It is safe to delete entries |
1784 | * from the array in the loop body. You should hold either the RCU lock |
1785 | * or the xa_lock while iterating. If you need to drop the lock, call |
1786 | * xas_pause() first. |
1787 | */ |
1788 | #define xas_for_each(xas, entry, max) \ |
1789 | for (entry = xas_find(xas, max); entry; \ |
1790 | entry = xas_next_entry(xas, max)) |
1791 | |
1792 | /** |
1793 | * xas_for_each_marked() - Iterate over a range of an XArray. |
1794 | * @xas: XArray operation state. |
1795 | * @entry: Entry retrieved from the array. |
1796 | * @max: Maximum index to retrieve from array. |
1797 | * @mark: Mark to search for. |
1798 | * |
1799 | * The loop body will be executed for each marked entry in the xarray |
1800 | * between the current xas position and @max. @entry will be set to |
1801 | * the entry retrieved from the xarray. It is safe to delete entries |
1802 | * from the array in the loop body. You should hold either the RCU lock |
1803 | * or the xa_lock while iterating. If you need to drop the lock, call |
1804 | * xas_pause() first. |
1805 | */ |
1806 | #define xas_for_each_marked(xas, entry, max, mark) \ |
1807 | for (entry = xas_find_marked(xas, max, mark); entry; \ |
1808 | entry = xas_next_marked(xas, max, mark)) |
1809 | |
1810 | /** |
1811 | * xas_for_each_conflict() - Iterate over a range of an XArray. |
1812 | * @xas: XArray operation state. |
1813 | * @entry: Entry retrieved from the array. |
1814 | * |
1815 | * The loop body will be executed for each entry in the XArray that |
1816 | * lies within the range specified by @xas. If the loop terminates |
1817 | * normally, @entry will be %NULL. The user may break out of the loop, |
1818 | * which will leave @entry set to the conflicting entry. The caller |
1819 | * may also call xa_set_err() to exit the loop while setting an error |
1820 | * to record the reason. |
1821 | */ |
1822 | #define xas_for_each_conflict(xas, entry) \ |
1823 | while ((entry = xas_find_conflict(xas))) |
1824 | |
1825 | void *__xas_next(struct xa_state *); |
1826 | void *__xas_prev(struct xa_state *); |
1827 | |
1828 | /** |
1829 | * xas_prev() - Move iterator to previous index. |
1830 | * @xas: XArray operation state. |
1831 | * |
1832 | * If the @xas was in an error state, it will remain in an error state |
1833 | * and this function will return %NULL. If the @xas has never been walked, |
1834 | * it will have the effect of calling xas_load(). Otherwise one will be |
1835 | * subtracted from the index and the state will be walked to the correct |
1836 | * location in the array for the next operation. |
1837 | * |
1838 | * If the iterator was referencing index 0, this function wraps |
1839 | * around to %ULONG_MAX. |
1840 | * |
1841 | * Return: The entry at the new index. This may be %NULL or an internal |
1842 | * entry. |
1843 | */ |
1844 | static inline void *xas_prev(struct xa_state *xas) |
1845 | { |
1846 | struct xa_node *node = xas->xa_node; |
1847 | |
1848 | if (unlikely(xas_not_node(node) || node->shift || |
1849 | xas->xa_offset == 0)) |
1850 | return __xas_prev(xas); |
1851 | |
1852 | xas->xa_index--; |
1853 | xas->xa_offset--; |
1854 | return xa_entry(xa: xas->xa, node, offset: xas->xa_offset); |
1855 | } |
1856 | |
1857 | /** |
1858 | * xas_next() - Move state to next index. |
1859 | * @xas: XArray operation state. |
1860 | * |
1861 | * If the @xas was in an error state, it will remain in an error state |
1862 | * and this function will return %NULL. If the @xas has never been walked, |
1863 | * it will have the effect of calling xas_load(). Otherwise one will be |
1864 | * added to the index and the state will be walked to the correct |
1865 | * location in the array for the next operation. |
1866 | * |
1867 | * If the iterator was referencing index %ULONG_MAX, this function wraps |
1868 | * around to 0. |
1869 | * |
1870 | * Return: The entry at the new index. This may be %NULL or an internal |
1871 | * entry. |
1872 | */ |
1873 | static inline void *xas_next(struct xa_state *xas) |
1874 | { |
1875 | struct xa_node *node = xas->xa_node; |
1876 | |
1877 | if (unlikely(xas_not_node(node) || node->shift || |
1878 | xas->xa_offset == XA_CHUNK_MASK)) |
1879 | return __xas_next(xas); |
1880 | |
1881 | xas->xa_index++; |
1882 | xas->xa_offset++; |
1883 | return xa_entry(xa: xas->xa, node, offset: xas->xa_offset); |
1884 | } |
1885 | |
1886 | #endif /* _LINUX_XARRAY_H */ |
1887 | |