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f6bb2a2c MW |
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 | |
3d0186bb | 7 | * Author: Matthew Wilcox <willy@infradead.org> |
3159f943 MW |
8 | * |
9 | * See Documentation/core-api/xarray.rst for how to use the XArray. | |
f6bb2a2c MW |
10 | */ |
11 | ||
22f56b8e | 12 | #include <linux/bitmap.h> |
3159f943 | 13 | #include <linux/bug.h> |
f8d5d0cc | 14 | #include <linux/compiler.h> |
d0aea4dc | 15 | #include <linux/err.h> |
9b89a035 | 16 | #include <linux/gfp.h> |
f8d5d0cc | 17 | #include <linux/kconfig.h> |
d0aea4dc AS |
18 | #include <linux/limits.h> |
19 | #include <linux/lockdep.h> | |
ad3d6c72 | 20 | #include <linux/rcupdate.h> |
1dd685c4 | 21 | #include <linux/sched/mm.h> |
f6bb2a2c | 22 | #include <linux/spinlock.h> |
3159f943 MW |
23 | #include <linux/types.h> |
24 | ||
d0aea4dc AS |
25 | struct list_lru; |
26 | ||
3159f943 MW |
27 | /* |
28 | * The bottom two bits of the entry determine how the XArray interprets | |
29 | * the contents: | |
30 | * | |
31 | * 00: Pointer entry | |
32 | * 10: Internal entry | |
33 | * x1: Value entry or tagged pointer | |
34 | * | |
35 | * Attempting to store internal entries in the XArray is a bug. | |
02c02bf1 MW |
36 | * |
37 | * Most internal entries are pointers to the next node in the tree. | |
38 | * The following internal entries have a special meaning: | |
39 | * | |
40 | * 0-62: Sibling entries | |
24a448b1 CX |
41 | * 256: Retry entry |
42 | * 257: Zero entry | |
ad3d6c72 MW |
43 | * |
44 | * Errors are also represented as internal entries, but use the negative | |
45 | * space (-4094 to -2). They're never stored in the slots array; only | |
46 | * returned by the normal API. | |
3159f943 MW |
47 | */ |
48 | ||
49 | #define BITS_PER_XA_VALUE (BITS_PER_LONG - 1) | |
50 | ||
51 | /** | |
52 | * xa_mk_value() - Create an XArray entry from an integer. | |
53 | * @v: Value to store in XArray. | |
54 | * | |
55 | * Context: Any context. | |
56 | * Return: An entry suitable for storing in the XArray. | |
57 | */ | |
58 | static inline void *xa_mk_value(unsigned long v) | |
59 | { | |
60 | WARN_ON((long)v < 0); | |
61 | return (void *)((v << 1) | 1); | |
62 | } | |
63 | ||
64 | /** | |
65 | * xa_to_value() - Get value stored in an XArray entry. | |
66 | * @entry: XArray entry. | |
67 | * | |
68 | * Context: Any context. | |
69 | * Return: The value stored in the XArray entry. | |
70 | */ | |
71 | static inline unsigned long xa_to_value(const void *entry) | |
72 | { | |
73 | return (unsigned long)entry >> 1; | |
74 | } | |
75 | ||
76 | /** | |
77 | * xa_is_value() - Determine if an entry is a value. | |
78 | * @entry: XArray entry. | |
79 | * | |
80 | * Context: Any context. | |
81 | * Return: True if the entry is a value, false if it is a pointer. | |
82 | */ | |
83 | static inline bool xa_is_value(const void *entry) | |
84 | { | |
85 | return (unsigned long)entry & 1; | |
86 | } | |
87 | ||
88 | /** | |
89 | * xa_tag_pointer() - Create an XArray entry for a tagged pointer. | |
90 | * @p: Plain pointer. | |
91 | * @tag: Tag value (0, 1 or 3). | |
92 | * | |
93 | * If the user of the XArray prefers, they can tag their pointers instead | |
94 | * of storing value entries. Three tags are available (0, 1 and 3). | |
95 | * These are distinct from the xa_mark_t as they are not replicated up | |
96 | * through the array and cannot be searched for. | |
97 | * | |
98 | * Context: Any context. | |
99 | * Return: An XArray entry. | |
100 | */ | |
101 | static inline void *xa_tag_pointer(void *p, unsigned long tag) | |
102 | { | |
103 | return (void *)((unsigned long)p | tag); | |
104 | } | |
105 | ||
106 | /** | |
107 | * xa_untag_pointer() - Turn an XArray entry into a plain pointer. | |
108 | * @entry: XArray entry. | |
109 | * | |
110 | * If you have stored a tagged pointer in the XArray, call this function | |
111 | * to get the untagged version of the pointer. | |
112 | * | |
113 | * Context: Any context. | |
114 | * Return: A pointer. | |
115 | */ | |
116 | static inline void *xa_untag_pointer(void *entry) | |
117 | { | |
118 | return (void *)((unsigned long)entry & ~3UL); | |
119 | } | |
120 | ||
121 | /** | |
122 | * xa_pointer_tag() - Get the tag stored in an XArray entry. | |
123 | * @entry: XArray entry. | |
124 | * | |
125 | * If you have stored a tagged pointer in the XArray, call this function | |
126 | * to get the tag of that pointer. | |
127 | * | |
128 | * Context: Any context. | |
129 | * Return: A tag. | |
130 | */ | |
131 | static inline unsigned int xa_pointer_tag(void *entry) | |
132 | { | |
133 | return (unsigned long)entry & 3UL; | |
134 | } | |
f6bb2a2c | 135 | |
02c02bf1 MW |
136 | /* |
137 | * xa_mk_internal() - Create an internal entry. | |
138 | * @v: Value to turn into an internal entry. | |
139 | * | |
b38f6c50 MW |
140 | * Internal entries are used for a number of purposes. Entries 0-255 are |
141 | * used for sibling entries (only 0-62 are used by the current code). 256 | |
142 | * is used for the retry entry. 257 is used for the reserved / zero entry. | |
143 | * Negative internal entries are used to represent errnos. Node pointers | |
144 | * are also tagged as internal entries in some situations. | |
145 | * | |
02c02bf1 MW |
146 | * Context: Any context. |
147 | * Return: An XArray internal entry corresponding to this value. | |
148 | */ | |
149 | static inline void *xa_mk_internal(unsigned long v) | |
150 | { | |
151 | return (void *)((v << 2) | 2); | |
152 | } | |
153 | ||
154 | /* | |
155 | * xa_to_internal() - Extract the value from an internal entry. | |
156 | * @entry: XArray entry. | |
157 | * | |
158 | * Context: Any context. | |
159 | * Return: The value which was stored in the internal entry. | |
160 | */ | |
161 | static inline unsigned long xa_to_internal(const void *entry) | |
162 | { | |
163 | return (unsigned long)entry >> 2; | |
164 | } | |
165 | ||
166 | /* | |
167 | * xa_is_internal() - Is the entry an internal entry? | |
168 | * @entry: XArray entry. | |
169 | * | |
170 | * Context: Any context. | |
171 | * Return: %true if the entry is an internal entry. | |
172 | */ | |
173 | static inline bool xa_is_internal(const void *entry) | |
174 | { | |
175 | return ((unsigned long)entry & 3) == 2; | |
176 | } | |
177 | ||
b38f6c50 MW |
178 | #define XA_ZERO_ENTRY xa_mk_internal(257) |
179 | ||
180 | /** | |
181 | * xa_is_zero() - Is the entry a zero entry? | |
182 | * @entry: Entry retrieved from the XArray | |
183 | * | |
184 | * The normal API will return NULL as the contents of a slot containing | |
185 | * a zero entry. You can only see zero entries by using the advanced API. | |
186 | * | |
187 | * Return: %true if the entry is a zero entry. | |
188 | */ | |
189 | static inline bool xa_is_zero(const void *entry) | |
190 | { | |
191 | return unlikely(entry == XA_ZERO_ENTRY); | |
192 | } | |
193 | ||
ad3d6c72 MW |
194 | /** |
195 | * xa_is_err() - Report whether an XArray operation returned an error | |
196 | * @entry: Result from calling an XArray function | |
197 | * | |
198 | * If an XArray operation cannot complete an operation, it will return | |
199 | * a special value indicating an error. This function tells you | |
200 | * whether an error occurred; xa_err() tells you which error occurred. | |
201 | * | |
202 | * Context: Any context. | |
203 | * Return: %true if the entry indicates an error. | |
204 | */ | |
205 | static inline bool xa_is_err(const void *entry) | |
206 | { | |
76b4e529 | 207 | return unlikely(xa_is_internal(entry) && |
edcddd4c | 208 | entry >= xa_mk_internal(-MAX_ERRNO)); |
ad3d6c72 MW |
209 | } |
210 | ||
211 | /** | |
212 | * xa_err() - Turn an XArray result into an errno. | |
213 | * @entry: Result from calling an XArray function. | |
214 | * | |
215 | * If an XArray operation cannot complete an operation, it will return | |
216 | * a special pointer value which encodes an errno. This function extracts | |
217 | * the errno from the pointer value, or returns 0 if the pointer does not | |
218 | * represent an errno. | |
219 | * | |
220 | * Context: Any context. | |
221 | * Return: A negative errno or 0. | |
222 | */ | |
223 | static inline int xa_err(void *entry) | |
224 | { | |
225 | /* xa_to_internal() would not do sign extension. */ | |
226 | if (xa_is_err(entry)) | |
227 | return (long)entry >> 2; | |
228 | return 0; | |
229 | } | |
230 | ||
a3e4d3f9 MW |
231 | /** |
232 | * struct xa_limit - Represents a range of IDs. | |
233 | * @min: The lowest ID to allocate (inclusive). | |
234 | * @max: The maximum ID to allocate (inclusive). | |
235 | * | |
236 | * This structure is used either directly or via the XA_LIMIT() macro | |
237 | * to communicate the range of IDs that are valid for allocation. | |
df59d0a4 | 238 | * Three common ranges are predefined for you: |
13bea898 RD |
239 | * * xa_limit_32b - [0 - UINT_MAX] |
240 | * * xa_limit_31b - [0 - INT_MAX] | |
df59d0a4 | 241 | * * xa_limit_16b - [0 - USHRT_MAX] |
a3e4d3f9 MW |
242 | */ |
243 | struct xa_limit { | |
244 | u32 max; | |
245 | u32 min; | |
246 | }; | |
247 | ||
248 | #define XA_LIMIT(_min, _max) (struct xa_limit) { .min = _min, .max = _max } | |
249 | ||
250 | #define xa_limit_32b XA_LIMIT(0, UINT_MAX) | |
251 | #define xa_limit_31b XA_LIMIT(0, INT_MAX) | |
df59d0a4 | 252 | #define xa_limit_16b XA_LIMIT(0, USHRT_MAX) |
a3e4d3f9 | 253 | |
9b89a035 MW |
254 | typedef unsigned __bitwise xa_mark_t; |
255 | #define XA_MARK_0 ((__force xa_mark_t)0U) | |
256 | #define XA_MARK_1 ((__force xa_mark_t)1U) | |
257 | #define XA_MARK_2 ((__force xa_mark_t)2U) | |
258 | #define XA_PRESENT ((__force xa_mark_t)8U) | |
259 | #define XA_MARK_MAX XA_MARK_2 | |
371c752d | 260 | #define XA_FREE_MARK XA_MARK_0 |
9b89a035 | 261 | |
58d6ea30 MW |
262 | enum xa_lock_type { |
263 | XA_LOCK_IRQ = 1, | |
264 | XA_LOCK_BH = 2, | |
265 | }; | |
266 | ||
9b89a035 MW |
267 | /* |
268 | * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags, | |
269 | * and we remain compatible with that. | |
270 | */ | |
58d6ea30 MW |
271 | #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) |
272 | #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) | |
371c752d | 273 | #define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U) |
3ccaf57a | 274 | #define XA_FLAGS_ZERO_BUSY ((__force gfp_t)8U) |
2fa044e5 | 275 | #define XA_FLAGS_ALLOC_WRAPPED ((__force gfp_t)16U) |
7b785645 | 276 | #define XA_FLAGS_ACCOUNT ((__force gfp_t)32U) |
9b89a035 MW |
277 | #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ |
278 | (__force unsigned)(mark))) | |
279 | ||
3ccaf57a | 280 | /* ALLOC is for a normal 0-based alloc. ALLOC1 is for an 1-based alloc */ |
371c752d | 281 | #define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK)) |
3ccaf57a | 282 | #define XA_FLAGS_ALLOC1 (XA_FLAGS_TRACK_FREE | XA_FLAGS_ZERO_BUSY) |
371c752d | 283 | |
f8d5d0cc MW |
284 | /** |
285 | * struct xarray - The anchor of the XArray. | |
286 | * @xa_lock: Lock that protects the contents of the XArray. | |
287 | * | |
288 | * To use the xarray, define it statically or embed it in your data structure. | |
289 | * It is a very small data structure, so it does not usually make sense to | |
290 | * allocate it separately and keep a pointer to it in your data structure. | |
291 | * | |
292 | * You may use the xa_lock to protect your own data structures as well. | |
293 | */ | |
294 | /* | |
295 | * If all of the entries in the array are NULL, @xa_head is a NULL pointer. | |
296 | * If the only non-NULL entry in the array is at index 0, @xa_head is that | |
297 | * entry. If any other entry in the array is non-NULL, @xa_head points | |
298 | * to an @xa_node. | |
299 | */ | |
300 | struct xarray { | |
301 | spinlock_t xa_lock; | |
302 | /* private: The rest of the data structure is not to be used directly. */ | |
303 | gfp_t xa_flags; | |
304 | void __rcu * xa_head; | |
305 | }; | |
306 | ||
307 | #define XARRAY_INIT(name, flags) { \ | |
308 | .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \ | |
309 | .xa_flags = flags, \ | |
310 | .xa_head = NULL, \ | |
311 | } | |
312 | ||
313 | /** | |
314 | * DEFINE_XARRAY_FLAGS() - Define an XArray with custom flags. | |
315 | * @name: A string that names your XArray. | |
316 | * @flags: XA_FLAG values. | |
317 | * | |
318 | * This is intended for file scope definitions of XArrays. It declares | |
319 | * and initialises an empty XArray with the chosen name and flags. It is | |
320 | * equivalent to calling xa_init_flags() on the array, but it does the | |
321 | * initialisation at compiletime instead of runtime. | |
322 | */ | |
323 | #define DEFINE_XARRAY_FLAGS(name, flags) \ | |
324 | struct xarray name = XARRAY_INIT(name, flags) | |
325 | ||
326 | /** | |
327 | * DEFINE_XARRAY() - Define an XArray. | |
328 | * @name: A string that names your XArray. | |
329 | * | |
330 | * This is intended for file scope definitions of XArrays. It declares | |
331 | * and initialises an empty XArray with the chosen name. It is equivalent | |
332 | * to calling xa_init() on the array, but it does the initialisation at | |
333 | * compiletime instead of runtime. | |
334 | */ | |
335 | #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) | |
336 | ||
371c752d | 337 | /** |
3ccaf57a | 338 | * DEFINE_XARRAY_ALLOC() - Define an XArray which allocates IDs starting at 0. |
371c752d MW |
339 | * @name: A string that names your XArray. |
340 | * | |
341 | * This is intended for file scope definitions of allocating XArrays. | |
342 | * See also DEFINE_XARRAY(). | |
343 | */ | |
344 | #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) | |
345 | ||
3ccaf57a MW |
346 | /** |
347 | * DEFINE_XARRAY_ALLOC1() - Define an XArray which allocates IDs starting at 1. | |
348 | * @name: A string that names your XArray. | |
349 | * | |
350 | * This is intended for file scope definitions of allocating XArrays. | |
351 | * See also DEFINE_XARRAY(). | |
352 | */ | |
353 | #define DEFINE_XARRAY_ALLOC1(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC1) | |
354 | ||
ad3d6c72 | 355 | void *xa_load(struct xarray *, unsigned long index); |
58d6ea30 | 356 | void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); |
9c16bb88 | 357 | void *xa_erase(struct xarray *, unsigned long index); |
0e9446c3 MW |
358 | void *xa_store_range(struct xarray *, unsigned long first, unsigned long last, |
359 | void *entry, gfp_t); | |
9b89a035 MW |
360 | bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); |
361 | void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); | |
362 | void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); | |
b803b428 MW |
363 | void *xa_find(struct xarray *xa, unsigned long *index, |
364 | unsigned long max, xa_mark_t) __attribute__((nonnull(2))); | |
365 | void *xa_find_after(struct xarray *xa, unsigned long *index, | |
366 | unsigned long max, xa_mark_t) __attribute__((nonnull(2))); | |
80a0a1a9 MW |
367 | unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, |
368 | unsigned long max, unsigned int n, xa_mark_t); | |
687149fc | 369 | void xa_destroy(struct xarray *); |
f8d5d0cc | 370 | |
02669b17 MW |
371 | /** |
372 | * xa_init_flags() - Initialise an empty XArray with flags. | |
373 | * @xa: XArray. | |
374 | * @flags: XA_FLAG values. | |
375 | * | |
376 | * If you need to initialise an XArray with special flags (eg you need | |
377 | * to take the lock from interrupt context), use this function instead | |
378 | * of xa_init(). | |
379 | * | |
380 | * Context: Any context. | |
381 | */ | |
382 | static inline void xa_init_flags(struct xarray *xa, gfp_t flags) | |
383 | { | |
384 | spin_lock_init(&xa->xa_lock); | |
385 | xa->xa_flags = flags; | |
386 | xa->xa_head = NULL; | |
387 | } | |
388 | ||
f8d5d0cc MW |
389 | /** |
390 | * xa_init() - Initialise an empty XArray. | |
391 | * @xa: XArray. | |
392 | * | |
393 | * An empty XArray is full of NULL entries. | |
394 | * | |
395 | * Context: Any context. | |
396 | */ | |
397 | static inline void xa_init(struct xarray *xa) | |
398 | { | |
399 | xa_init_flags(xa, 0); | |
400 | } | |
401 | ||
ad3d6c72 MW |
402 | /** |
403 | * xa_empty() - Determine if an array has any present entries. | |
404 | * @xa: XArray. | |
405 | * | |
406 | * Context: Any context. | |
407 | * Return: %true if the array contains only NULL pointers. | |
408 | */ | |
409 | static inline bool xa_empty(const struct xarray *xa) | |
410 | { | |
411 | return xa->xa_head == NULL; | |
412 | } | |
413 | ||
9b89a035 MW |
414 | /** |
415 | * xa_marked() - Inquire whether any entry in this array has a mark set | |
416 | * @xa: Array | |
417 | * @mark: Mark value | |
418 | * | |
419 | * Context: Any context. | |
420 | * Return: %true if any entry has this mark set. | |
421 | */ | |
422 | static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) | |
423 | { | |
424 | return xa->xa_flags & XA_FLAGS_MARK(mark); | |
425 | } | |
426 | ||
00ed452c MWO |
427 | /** |
428 | * xa_for_each_range() - Iterate over a portion of an XArray. | |
429 | * @xa: XArray. | |
430 | * @index: Index of @entry. | |
431 | * @entry: Entry retrieved from array. | |
432 | * @start: First index to retrieve from array. | |
433 | * @last: Last index to retrieve from array. | |
434 | * | |
435 | * During the iteration, @entry will have the value of the entry stored | |
436 | * in @xa at @index. You may modify @index during the iteration if you | |
437 | * want to skip or reprocess indices. It is safe to modify the array | |
438 | * during the iteration. At the end of the iteration, @entry will be set | |
439 | * to NULL and @index will have a value less than or equal to max. | |
440 | * | |
441 | * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have | |
442 | * to handle your own locking with xas_for_each(), and if you have to unlock | |
443 | * after each iteration, it will also end up being O(n.log(n)). | |
444 | * xa_for_each_range() will spin if it hits a retry entry; if you intend to | |
445 | * see retry entries, you should use the xas_for_each() iterator instead. | |
446 | * The xas_for_each() iterator will expand into more inline code than | |
447 | * xa_for_each_range(). | |
448 | * | |
449 | * Context: Any context. Takes and releases the RCU lock. | |
450 | */ | |
451 | #define xa_for_each_range(xa, index, entry, start, last) \ | |
452 | for (index = start, \ | |
453 | entry = xa_find(xa, &index, last, XA_PRESENT); \ | |
454 | entry; \ | |
455 | entry = xa_find_after(xa, &index, last, XA_PRESENT)) | |
456 | ||
b803b428 | 457 | /** |
4a31896c | 458 | * xa_for_each_start() - Iterate over a portion of an XArray. |
b803b428 | 459 | * @xa: XArray. |
4a31896c | 460 | * @index: Index of @entry. |
b803b428 | 461 | * @entry: Entry retrieved from array. |
4a31896c MW |
462 | * @start: First index to retrieve from array. |
463 | * | |
464 | * During the iteration, @entry will have the value of the entry stored | |
465 | * in @xa at @index. You may modify @index during the iteration if you | |
466 | * want to skip or reprocess indices. It is safe to modify the array | |
467 | * during the iteration. At the end of the iteration, @entry will be set | |
468 | * to NULL and @index will have a value less than or equal to max. | |
469 | * | |
470 | * xa_for_each_start() is O(n.log(n)) while xas_for_each() is O(n). You have | |
471 | * to handle your own locking with xas_for_each(), and if you have to unlock | |
472 | * after each iteration, it will also end up being O(n.log(n)). | |
473 | * xa_for_each_start() will spin if it hits a retry entry; if you intend to | |
474 | * see retry entries, you should use the xas_for_each() iterator instead. | |
475 | * The xas_for_each() iterator will expand into more inline code than | |
476 | * xa_for_each_start(). | |
477 | * | |
478 | * Context: Any context. Takes and releases the RCU lock. | |
479 | */ | |
00ed452c MWO |
480 | #define xa_for_each_start(xa, index, entry, start) \ |
481 | xa_for_each_range(xa, index, entry, start, ULONG_MAX) | |
4a31896c MW |
482 | |
483 | /** | |
484 | * xa_for_each() - Iterate over present entries in an XArray. | |
485 | * @xa: XArray. | |
b803b428 | 486 | * @index: Index of @entry. |
4a31896c | 487 | * @entry: Entry retrieved from array. |
b803b428 | 488 | * |
4a31896c MW |
489 | * During the iteration, @entry will have the value of the entry stored |
490 | * in @xa at @index. You may modify @index during the iteration if you want | |
491 | * to skip or reprocess indices. It is safe to modify the array during the | |
492 | * iteration. At the end of the iteration, @entry will be set to NULL and | |
493 | * @index will have a value less than or equal to max. | |
b803b428 MW |
494 | * |
495 | * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have | |
496 | * to handle your own locking with xas_for_each(), and if you have to unlock | |
497 | * after each iteration, it will also end up being O(n.log(n)). xa_for_each() | |
498 | * will spin if it hits a retry entry; if you intend to see retry entries, | |
499 | * you should use the xas_for_each() iterator instead. The xas_for_each() | |
500 | * iterator will expand into more inline code than xa_for_each(). | |
501 | * | |
502 | * Context: Any context. Takes and releases the RCU lock. | |
503 | */ | |
4a31896c MW |
504 | #define xa_for_each(xa, index, entry) \ |
505 | xa_for_each_start(xa, index, entry, 0) | |
506 | ||
507 | /** | |
508 | * xa_for_each_marked() - Iterate over marked entries in an XArray. | |
509 | * @xa: XArray. | |
510 | * @index: Index of @entry. | |
511 | * @entry: Entry retrieved from array. | |
512 | * @filter: Selection criterion. | |
513 | * | |
514 | * During the iteration, @entry will have the value of the entry stored | |
515 | * in @xa at @index. The iteration will skip all entries in the array | |
516 | * which do not match @filter. You may modify @index during the iteration | |
517 | * if you want to skip or reprocess indices. It is safe to modify the array | |
518 | * during the iteration. At the end of the iteration, @entry will be set to | |
519 | * NULL and @index will have a value less than or equal to max. | |
520 | * | |
521 | * xa_for_each_marked() is O(n.log(n)) while xas_for_each_marked() is O(n). | |
522 | * You have to handle your own locking with xas_for_each(), and if you have | |
523 | * to unlock after each iteration, it will also end up being O(n.log(n)). | |
524 | * xa_for_each_marked() will spin if it hits a retry entry; if you intend to | |
525 | * see retry entries, you should use the xas_for_each_marked() iterator | |
526 | * instead. The xas_for_each_marked() iterator will expand into more inline | |
527 | * code than xa_for_each_marked(). | |
528 | * | |
529 | * Context: Any context. Takes and releases the RCU lock. | |
530 | */ | |
531 | #define xa_for_each_marked(xa, index, entry, filter) \ | |
532 | for (index = 0, entry = xa_find(xa, &index, ULONG_MAX, filter); \ | |
533 | entry; entry = xa_find_after(xa, &index, ULONG_MAX, filter)) | |
b803b428 | 534 | |
f6bb2a2c MW |
535 | #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) |
536 | #define xa_lock(xa) spin_lock(&(xa)->xa_lock) | |
537 | #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) | |
538 | #define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock) | |
539 | #define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock) | |
540 | #define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock) | |
541 | #define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock) | |
542 | #define xa_lock_irqsave(xa, flags) \ | |
543 | spin_lock_irqsave(&(xa)->xa_lock, flags) | |
544 | #define xa_unlock_irqrestore(xa, flags) \ | |
545 | spin_unlock_irqrestore(&(xa)->xa_lock, flags) | |
82a95849 MWO |
546 | #define xa_lock_nested(xa, subclass) \ |
547 | spin_lock_nested(&(xa)->xa_lock, subclass) | |
548 | #define xa_lock_bh_nested(xa, subclass) \ | |
549 | spin_lock_bh_nested(&(xa)->xa_lock, subclass) | |
550 | #define xa_lock_irq_nested(xa, subclass) \ | |
551 | spin_lock_irq_nested(&(xa)->xa_lock, subclass) | |
552 | #define xa_lock_irqsave_nested(xa, flags, subclass) \ | |
553 | spin_lock_irqsave_nested(&(xa)->xa_lock, flags, subclass) | |
f6bb2a2c | 554 | |
9b89a035 | 555 | /* |
58d6ea30 MW |
556 | * Versions of the normal API which require the caller to hold the |
557 | * xa_lock. If the GFP flags allow it, they will drop the lock to | |
558 | * allocate memory, then reacquire it afterwards. These functions | |
559 | * may also re-enable interrupts if the XArray flags indicate the | |
560 | * locking should be interrupt safe. | |
561 | */ | |
562 | void *__xa_erase(struct xarray *, unsigned long index); | |
563 | void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); | |
41aec91f MW |
564 | void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old, |
565 | void *entry, gfp_t); | |
f818b82b MW |
566 | int __must_check __xa_insert(struct xarray *, unsigned long index, |
567 | void *entry, gfp_t); | |
a3e4d3f9 MW |
568 | int __must_check __xa_alloc(struct xarray *, u32 *id, void *entry, |
569 | struct xa_limit, gfp_t); | |
2fa044e5 MW |
570 | int __must_check __xa_alloc_cyclic(struct xarray *, u32 *id, void *entry, |
571 | struct xa_limit, u32 *next, gfp_t); | |
9b89a035 MW |
572 | void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); |
573 | void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); | |
574 | ||
84e5acb7 MW |
575 | /** |
576 | * xa_store_bh() - Store this entry in the XArray. | |
577 | * @xa: XArray. | |
578 | * @index: Index into array. | |
579 | * @entry: New entry. | |
580 | * @gfp: Memory allocation flags. | |
581 | * | |
582 | * This function is like calling xa_store() except it disables softirqs | |
583 | * while holding the array lock. | |
584 | * | |
585 | * Context: Any context. Takes and releases the xa_lock while | |
586 | * disabling softirqs. | |
01f39c1c | 587 | * Return: The old entry at this index or xa_err() if an error happened. |
84e5acb7 MW |
588 | */ |
589 | static inline void *xa_store_bh(struct xarray *xa, unsigned long index, | |
590 | void *entry, gfp_t gfp) | |
591 | { | |
592 | void *curr; | |
593 | ||
1dd685c4 | 594 | might_alloc(gfp); |
84e5acb7 MW |
595 | xa_lock_bh(xa); |
596 | curr = __xa_store(xa, index, entry, gfp); | |
597 | xa_unlock_bh(xa); | |
598 | ||
599 | return curr; | |
600 | } | |
601 | ||
602 | /** | |
19ba9ecf | 603 | * xa_store_irq() - Store this entry in the XArray. |
84e5acb7 MW |
604 | * @xa: XArray. |
605 | * @index: Index into array. | |
606 | * @entry: New entry. | |
607 | * @gfp: Memory allocation flags. | |
608 | * | |
609 | * This function is like calling xa_store() except it disables interrupts | |
610 | * while holding the array lock. | |
611 | * | |
612 | * Context: Process context. Takes and releases the xa_lock while | |
613 | * disabling interrupts. | |
01f39c1c | 614 | * Return: The old entry at this index or xa_err() if an error happened. |
84e5acb7 MW |
615 | */ |
616 | static inline void *xa_store_irq(struct xarray *xa, unsigned long index, | |
617 | void *entry, gfp_t gfp) | |
618 | { | |
619 | void *curr; | |
620 | ||
1dd685c4 | 621 | might_alloc(gfp); |
84e5acb7 MW |
622 | xa_lock_irq(xa); |
623 | curr = __xa_store(xa, index, entry, gfp); | |
624 | xa_unlock_irq(xa); | |
625 | ||
626 | return curr; | |
627 | } | |
628 | ||
58d6ea30 MW |
629 | /** |
630 | * xa_erase_bh() - Erase this entry from the XArray. | |
631 | * @xa: XArray. | |
632 | * @index: Index of entry. | |
633 | * | |
809ab937 MW |
634 | * After this function returns, loading from @index will return %NULL. |
635 | * If the index is part of a multi-index entry, all indices will be erased | |
636 | * and none of the entries will be part of a multi-index entry. | |
58d6ea30 | 637 | * |
804dfaf0 | 638 | * Context: Any context. Takes and releases the xa_lock while |
58d6ea30 MW |
639 | * disabling softirqs. |
640 | * Return: The entry which used to be at this index. | |
641 | */ | |
642 | static inline void *xa_erase_bh(struct xarray *xa, unsigned long index) | |
643 | { | |
644 | void *entry; | |
645 | ||
646 | xa_lock_bh(xa); | |
647 | entry = __xa_erase(xa, index); | |
648 | xa_unlock_bh(xa); | |
649 | ||
650 | return entry; | |
651 | } | |
652 | ||
653 | /** | |
654 | * xa_erase_irq() - Erase this entry from the XArray. | |
655 | * @xa: XArray. | |
656 | * @index: Index of entry. | |
657 | * | |
809ab937 MW |
658 | * After this function returns, loading from @index will return %NULL. |
659 | * If the index is part of a multi-index entry, all indices will be erased | |
660 | * and none of the entries will be part of a multi-index entry. | |
58d6ea30 MW |
661 | * |
662 | * Context: Process context. Takes and releases the xa_lock while | |
663 | * disabling interrupts. | |
664 | * Return: The entry which used to be at this index. | |
665 | */ | |
666 | static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) | |
667 | { | |
668 | void *entry; | |
669 | ||
670 | xa_lock_irq(xa); | |
671 | entry = __xa_erase(xa, index); | |
672 | xa_unlock_irq(xa); | |
673 | ||
674 | return entry; | |
675 | } | |
676 | ||
c5beb07e MW |
677 | /** |
678 | * xa_cmpxchg() - Conditionally replace an entry in the XArray. | |
679 | * @xa: XArray. | |
680 | * @index: Index into array. | |
681 | * @old: Old value to test against. | |
682 | * @entry: New value to place in array. | |
683 | * @gfp: Memory allocation flags. | |
684 | * | |
685 | * If the entry at @index is the same as @old, replace it with @entry. | |
686 | * If the return value is equal to @old, then the exchange was successful. | |
687 | * | |
688 | * Context: Any context. Takes and releases the xa_lock. May sleep | |
689 | * if the @gfp flags permit. | |
690 | * Return: The old value at this index or xa_err() if an error happened. | |
691 | */ | |
692 | static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index, | |
693 | void *old, void *entry, gfp_t gfp) | |
694 | { | |
695 | void *curr; | |
696 | ||
1dd685c4 | 697 | might_alloc(gfp); |
c5beb07e MW |
698 | xa_lock(xa); |
699 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); | |
700 | xa_unlock(xa); | |
701 | ||
702 | return curr; | |
703 | } | |
704 | ||
55f3f7ea MW |
705 | /** |
706 | * xa_cmpxchg_bh() - Conditionally replace an entry in the XArray. | |
707 | * @xa: XArray. | |
708 | * @index: Index into array. | |
709 | * @old: Old value to test against. | |
710 | * @entry: New value to place in array. | |
711 | * @gfp: Memory allocation flags. | |
712 | * | |
713 | * This function is like calling xa_cmpxchg() except it disables softirqs | |
714 | * while holding the array lock. | |
715 | * | |
716 | * Context: Any context. Takes and releases the xa_lock while | |
717 | * disabling softirqs. May sleep if the @gfp flags permit. | |
718 | * Return: The old value at this index or xa_err() if an error happened. | |
719 | */ | |
720 | static inline void *xa_cmpxchg_bh(struct xarray *xa, unsigned long index, | |
721 | void *old, void *entry, gfp_t gfp) | |
722 | { | |
723 | void *curr; | |
724 | ||
1dd685c4 | 725 | might_alloc(gfp); |
55f3f7ea MW |
726 | xa_lock_bh(xa); |
727 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); | |
728 | xa_unlock_bh(xa); | |
729 | ||
730 | return curr; | |
731 | } | |
732 | ||
733 | /** | |
734 | * xa_cmpxchg_irq() - Conditionally replace an entry in the XArray. | |
735 | * @xa: XArray. | |
736 | * @index: Index into array. | |
737 | * @old: Old value to test against. | |
738 | * @entry: New value to place in array. | |
739 | * @gfp: Memory allocation flags. | |
740 | * | |
741 | * This function is like calling xa_cmpxchg() except it disables interrupts | |
742 | * while holding the array lock. | |
743 | * | |
744 | * Context: Process context. Takes and releases the xa_lock while | |
745 | * disabling interrupts. May sleep if the @gfp flags permit. | |
746 | * Return: The old value at this index or xa_err() if an error happened. | |
747 | */ | |
748 | static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, | |
749 | void *old, void *entry, gfp_t gfp) | |
750 | { | |
751 | void *curr; | |
752 | ||
1dd685c4 | 753 | might_alloc(gfp); |
55f3f7ea MW |
754 | xa_lock_irq(xa); |
755 | curr = __xa_cmpxchg(xa, index, old, entry, gfp); | |
756 | xa_unlock_irq(xa); | |
757 | ||
758 | return curr; | |
759 | } | |
760 | ||
c5beb07e MW |
761 | /** |
762 | * xa_insert() - Store this entry in the XArray unless another entry is | |
763 | * already present. | |
764 | * @xa: XArray. | |
765 | * @index: Index into array. | |
766 | * @entry: New entry. | |
767 | * @gfp: Memory allocation flags. | |
768 | * | |
b0606fed MW |
769 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
770 | * if no entry is present. Inserting will fail if a reserved entry is | |
771 | * present, even though loading from this index will return NULL. | |
c5beb07e | 772 | * |
b0606fed MW |
773 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
774 | * the @gfp flags permit. | |
fd9dc93e | 775 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
c5beb07e MW |
776 | * -ENOMEM if memory could not be allocated. |
777 | */ | |
f818b82b MW |
778 | static inline int __must_check xa_insert(struct xarray *xa, |
779 | unsigned long index, void *entry, gfp_t gfp) | |
c5beb07e | 780 | { |
b0606fed MW |
781 | int err; |
782 | ||
1dd685c4 | 783 | might_alloc(gfp); |
b0606fed MW |
784 | xa_lock(xa); |
785 | err = __xa_insert(xa, index, entry, gfp); | |
786 | xa_unlock(xa); | |
787 | ||
788 | return err; | |
789 | } | |
790 | ||
791 | /** | |
792 | * xa_insert_bh() - Store this entry in the XArray unless another entry is | |
793 | * already present. | |
794 | * @xa: XArray. | |
795 | * @index: Index into array. | |
796 | * @entry: New entry. | |
797 | * @gfp: Memory allocation flags. | |
798 | * | |
799 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) | |
800 | * if no entry is present. Inserting will fail if a reserved entry is | |
801 | * present, even though loading from this index will return NULL. | |
802 | * | |
803 | * Context: Any context. Takes and releases the xa_lock while | |
804 | * disabling softirqs. May sleep if the @gfp flags permit. | |
fd9dc93e | 805 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
b0606fed MW |
806 | * -ENOMEM if memory could not be allocated. |
807 | */ | |
f818b82b MW |
808 | static inline int __must_check xa_insert_bh(struct xarray *xa, |
809 | unsigned long index, void *entry, gfp_t gfp) | |
b0606fed MW |
810 | { |
811 | int err; | |
812 | ||
1dd685c4 | 813 | might_alloc(gfp); |
b0606fed MW |
814 | xa_lock_bh(xa); |
815 | err = __xa_insert(xa, index, entry, gfp); | |
816 | xa_unlock_bh(xa); | |
817 | ||
818 | return err; | |
819 | } | |
820 | ||
821 | /** | |
822 | * xa_insert_irq() - Store this entry in the XArray unless another entry is | |
823 | * already present. | |
824 | * @xa: XArray. | |
825 | * @index: Index into array. | |
826 | * @entry: New entry. | |
827 | * @gfp: Memory allocation flags. | |
828 | * | |
829 | * Inserting a NULL entry will store a reserved entry (like xa_reserve()) | |
830 | * if no entry is present. Inserting will fail if a reserved entry is | |
831 | * present, even though loading from this index will return NULL. | |
832 | * | |
833 | * Context: Process context. Takes and releases the xa_lock while | |
834 | * disabling interrupts. May sleep if the @gfp flags permit. | |
fd9dc93e | 835 | * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
b0606fed MW |
836 | * -ENOMEM if memory could not be allocated. |
837 | */ | |
f818b82b MW |
838 | static inline int __must_check xa_insert_irq(struct xarray *xa, |
839 | unsigned long index, void *entry, gfp_t gfp) | |
b0606fed MW |
840 | { |
841 | int err; | |
842 | ||
1dd685c4 | 843 | might_alloc(gfp); |
b0606fed MW |
844 | xa_lock_irq(xa); |
845 | err = __xa_insert(xa, index, entry, gfp); | |
846 | xa_unlock_irq(xa); | |
847 | ||
848 | return err; | |
c5beb07e MW |
849 | } |
850 | ||
371c752d MW |
851 | /** |
852 | * xa_alloc() - Find somewhere to store this entry in the XArray. | |
853 | * @xa: XArray. | |
854 | * @id: Pointer to ID. | |
371c752d | 855 | * @entry: New entry. |
a3e4d3f9 | 856 | * @limit: Range of ID to allocate. |
371c752d MW |
857 | * @gfp: Memory allocation flags. |
858 | * | |
a3e4d3f9 MW |
859 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
860 | * stores the index into the @id pointer, then stores the entry at | |
861 | * that index. A concurrent lookup will not see an uninitialised @id. | |
371c752d | 862 | * |
e7716c74 PS |
863 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
864 | * in xa_init_flags(). | |
865 | * | |
a3e4d3f9 | 866 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
371c752d | 867 | * the @gfp flags permit. |
a3e4d3f9 MW |
868 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
869 | * -EBUSY if there are no free entries in @limit. | |
371c752d | 870 | */ |
a3e4d3f9 MW |
871 | static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, |
872 | void *entry, struct xa_limit limit, gfp_t gfp) | |
371c752d MW |
873 | { |
874 | int err; | |
875 | ||
1dd685c4 | 876 | might_alloc(gfp); |
371c752d | 877 | xa_lock(xa); |
a3e4d3f9 | 878 | err = __xa_alloc(xa, id, entry, limit, gfp); |
371c752d MW |
879 | xa_unlock(xa); |
880 | ||
881 | return err; | |
882 | } | |
883 | ||
884 | /** | |
885 | * xa_alloc_bh() - Find somewhere to store this entry in the XArray. | |
886 | * @xa: XArray. | |
887 | * @id: Pointer to ID. | |
371c752d | 888 | * @entry: New entry. |
a3e4d3f9 | 889 | * @limit: Range of ID to allocate. |
371c752d MW |
890 | * @gfp: Memory allocation flags. |
891 | * | |
a3e4d3f9 MW |
892 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
893 | * stores the index into the @id pointer, then stores the entry at | |
894 | * that index. A concurrent lookup will not see an uninitialised @id. | |
371c752d | 895 | * |
e7716c74 PS |
896 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
897 | * in xa_init_flags(). | |
898 | * | |
804dfaf0 | 899 | * Context: Any context. Takes and releases the xa_lock while |
371c752d | 900 | * disabling softirqs. May sleep if the @gfp flags permit. |
a3e4d3f9 MW |
901 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
902 | * -EBUSY if there are no free entries in @limit. | |
371c752d | 903 | */ |
a3e4d3f9 MW |
904 | static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, |
905 | void *entry, struct xa_limit limit, gfp_t gfp) | |
371c752d MW |
906 | { |
907 | int err; | |
908 | ||
1dd685c4 | 909 | might_alloc(gfp); |
371c752d | 910 | xa_lock_bh(xa); |
a3e4d3f9 | 911 | err = __xa_alloc(xa, id, entry, limit, gfp); |
371c752d MW |
912 | xa_unlock_bh(xa); |
913 | ||
914 | return err; | |
915 | } | |
916 | ||
917 | /** | |
918 | * xa_alloc_irq() - Find somewhere to store this entry in the XArray. | |
919 | * @xa: XArray. | |
920 | * @id: Pointer to ID. | |
371c752d | 921 | * @entry: New entry. |
a3e4d3f9 | 922 | * @limit: Range of ID to allocate. |
371c752d MW |
923 | * @gfp: Memory allocation flags. |
924 | * | |
a3e4d3f9 MW |
925 | * Finds an empty entry in @xa between @limit.min and @limit.max, |
926 | * stores the index into the @id pointer, then stores the entry at | |
927 | * that index. A concurrent lookup will not see an uninitialised @id. | |
371c752d | 928 | * |
e7716c74 PS |
929 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
930 | * in xa_init_flags(). | |
931 | * | |
371c752d MW |
932 | * Context: Process context. Takes and releases the xa_lock while |
933 | * disabling interrupts. May sleep if the @gfp flags permit. | |
a3e4d3f9 MW |
934 | * Return: 0 on success, -ENOMEM if memory could not be allocated or |
935 | * -EBUSY if there are no free entries in @limit. | |
371c752d | 936 | */ |
a3e4d3f9 MW |
937 | static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, |
938 | void *entry, struct xa_limit limit, gfp_t gfp) | |
371c752d MW |
939 | { |
940 | int err; | |
941 | ||
1dd685c4 | 942 | might_alloc(gfp); |
371c752d | 943 | xa_lock_irq(xa); |
a3e4d3f9 | 944 | err = __xa_alloc(xa, id, entry, limit, gfp); |
371c752d MW |
945 | xa_unlock_irq(xa); |
946 | ||
947 | return err; | |
948 | } | |
949 | ||
2fa044e5 MW |
950 | /** |
951 | * xa_alloc_cyclic() - Find somewhere to store this entry in the XArray. | |
952 | * @xa: XArray. | |
953 | * @id: Pointer to ID. | |
954 | * @entry: New entry. | |
955 | * @limit: Range of allocated ID. | |
956 | * @next: Pointer to next ID to allocate. | |
957 | * @gfp: Memory allocation flags. | |
958 | * | |
959 | * Finds an empty entry in @xa between @limit.min and @limit.max, | |
960 | * stores the index into the @id pointer, then stores the entry at | |
961 | * that index. A concurrent lookup will not see an uninitialised @id. | |
962 | * The search for an empty entry will start at @next and will wrap | |
963 | * around if necessary. | |
964 | * | |
e7716c74 PS |
965 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
966 | * in xa_init_flags(). | |
967 | * | |
2fa044e5 MW |
968 | * Context: Any context. Takes and releases the xa_lock. May sleep if |
969 | * the @gfp flags permit. | |
970 | * Return: 0 if the allocation succeeded without wrapping. 1 if the | |
971 | * allocation succeeded after wrapping, -ENOMEM if memory could not be | |
972 | * allocated or -EBUSY if there are no free entries in @limit. | |
973 | */ | |
974 | static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, | |
975 | struct xa_limit limit, u32 *next, gfp_t gfp) | |
976 | { | |
977 | int err; | |
978 | ||
1dd685c4 | 979 | might_alloc(gfp); |
2fa044e5 MW |
980 | xa_lock(xa); |
981 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); | |
982 | xa_unlock(xa); | |
983 | ||
984 | return err; | |
985 | } | |
986 | ||
987 | /** | |
988 | * xa_alloc_cyclic_bh() - Find somewhere to store this entry in the XArray. | |
989 | * @xa: XArray. | |
990 | * @id: Pointer to ID. | |
991 | * @entry: New entry. | |
992 | * @limit: Range of allocated ID. | |
993 | * @next: Pointer to next ID to allocate. | |
994 | * @gfp: Memory allocation flags. | |
995 | * | |
996 | * Finds an empty entry in @xa between @limit.min and @limit.max, | |
997 | * stores the index into the @id pointer, then stores the entry at | |
998 | * that index. A concurrent lookup will not see an uninitialised @id. | |
999 | * The search for an empty entry will start at @next and will wrap | |
1000 | * around if necessary. | |
1001 | * | |
e7716c74 PS |
1002 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
1003 | * in xa_init_flags(). | |
1004 | * | |
2fa044e5 MW |
1005 | * Context: Any context. Takes and releases the xa_lock while |
1006 | * disabling softirqs. May sleep if the @gfp flags permit. | |
1007 | * Return: 0 if the allocation succeeded without wrapping. 1 if the | |
1008 | * allocation succeeded after wrapping, -ENOMEM if memory could not be | |
1009 | * allocated or -EBUSY if there are no free entries in @limit. | |
1010 | */ | |
1011 | static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, | |
1012 | struct xa_limit limit, u32 *next, gfp_t gfp) | |
1013 | { | |
1014 | int err; | |
1015 | ||
1dd685c4 | 1016 | might_alloc(gfp); |
2fa044e5 MW |
1017 | xa_lock_bh(xa); |
1018 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); | |
1019 | xa_unlock_bh(xa); | |
1020 | ||
1021 | return err; | |
1022 | } | |
1023 | ||
1024 | /** | |
1025 | * xa_alloc_cyclic_irq() - Find somewhere to store this entry in the XArray. | |
1026 | * @xa: XArray. | |
1027 | * @id: Pointer to ID. | |
1028 | * @entry: New entry. | |
1029 | * @limit: Range of allocated ID. | |
1030 | * @next: Pointer to next ID to allocate. | |
1031 | * @gfp: Memory allocation flags. | |
1032 | * | |
1033 | * Finds an empty entry in @xa between @limit.min and @limit.max, | |
1034 | * stores the index into the @id pointer, then stores the entry at | |
1035 | * that index. A concurrent lookup will not see an uninitialised @id. | |
1036 | * The search for an empty entry will start at @next and will wrap | |
1037 | * around if necessary. | |
1038 | * | |
e7716c74 PS |
1039 | * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set |
1040 | * in xa_init_flags(). | |
1041 | * | |
2fa044e5 MW |
1042 | * Context: Process context. Takes and releases the xa_lock while |
1043 | * disabling interrupts. May sleep if the @gfp flags permit. | |
1044 | * Return: 0 if the allocation succeeded without wrapping. 1 if the | |
1045 | * allocation succeeded after wrapping, -ENOMEM if memory could not be | |
1046 | * allocated or -EBUSY if there are no free entries in @limit. | |
1047 | */ | |
1048 | static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry, | |
1049 | struct xa_limit limit, u32 *next, gfp_t gfp) | |
1050 | { | |
1051 | int err; | |
1052 | ||
1dd685c4 | 1053 | might_alloc(gfp); |
2fa044e5 MW |
1054 | xa_lock_irq(xa); |
1055 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); | |
1056 | xa_unlock_irq(xa); | |
1057 | ||
1058 | return err; | |
1059 | } | |
1060 | ||
4c0608f4 MW |
1061 | /** |
1062 | * xa_reserve() - Reserve this index in the XArray. | |
1063 | * @xa: XArray. | |
1064 | * @index: Index into array. | |
1065 | * @gfp: Memory allocation flags. | |
1066 | * | |
1067 | * Ensures there is somewhere to store an entry at @index in the array. | |
1068 | * If there is already something stored at @index, this function does | |
1069 | * nothing. If there was nothing there, the entry is marked as reserved. | |
1070 | * Loading from a reserved entry returns a %NULL pointer. | |
1071 | * | |
1072 | * If you do not use the entry that you have reserved, call xa_release() | |
1073 | * or xa_erase() to free any unnecessary memory. | |
1074 | * | |
1075 | * Context: Any context. Takes and releases the xa_lock. | |
1076 | * May sleep if the @gfp flags permit. | |
1077 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. | |
1078 | */ | |
f818b82b | 1079 | static inline __must_check |
4c0608f4 MW |
1080 | int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) |
1081 | { | |
962033d5 | 1082 | return xa_err(xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
4c0608f4 MW |
1083 | } |
1084 | ||
1085 | /** | |
1086 | * xa_reserve_bh() - Reserve this index in the XArray. | |
1087 | * @xa: XArray. | |
1088 | * @index: Index into array. | |
1089 | * @gfp: Memory allocation flags. | |
1090 | * | |
1091 | * A softirq-disabling version of xa_reserve(). | |
1092 | * | |
1093 | * Context: Any context. Takes and releases the xa_lock while | |
1094 | * disabling softirqs. | |
1095 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. | |
1096 | */ | |
f818b82b | 1097 | static inline __must_check |
4c0608f4 MW |
1098 | int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp) |
1099 | { | |
962033d5 | 1100 | return xa_err(xa_cmpxchg_bh(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
4c0608f4 MW |
1101 | } |
1102 | ||
1103 | /** | |
1104 | * xa_reserve_irq() - Reserve this index in the XArray. | |
1105 | * @xa: XArray. | |
1106 | * @index: Index into array. | |
1107 | * @gfp: Memory allocation flags. | |
1108 | * | |
1109 | * An interrupt-disabling version of xa_reserve(). | |
1110 | * | |
1111 | * Context: Process context. Takes and releases the xa_lock while | |
1112 | * disabling interrupts. | |
1113 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed. | |
1114 | */ | |
f818b82b | 1115 | static inline __must_check |
4c0608f4 MW |
1116 | int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) |
1117 | { | |
962033d5 | 1118 | return xa_err(xa_cmpxchg_irq(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
4c0608f4 MW |
1119 | } |
1120 | ||
c5beb07e MW |
1121 | /** |
1122 | * xa_release() - Release a reserved entry. | |
1123 | * @xa: XArray. | |
1124 | * @index: Index of entry. | |
1125 | * | |
1126 | * After calling xa_reserve(), you can call this function to release the | |
1127 | * reservation. If the entry at @index has been stored to, this function | |
1128 | * will do nothing. | |
1129 | */ | |
1130 | static inline void xa_release(struct xarray *xa, unsigned long index) | |
1131 | { | |
b38f6c50 | 1132 | xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0); |
c5beb07e MW |
1133 | } |
1134 | ||
02c02bf1 MW |
1135 | /* Everything below here is the Advanced API. Proceed with caution. */ |
1136 | ||
1137 | /* | |
1138 | * The xarray is constructed out of a set of 'chunks' of pointers. Choosing | |
1139 | * the best chunk size requires some tradeoffs. A power of two recommends | |
1140 | * itself so that we can walk the tree based purely on shifts and masks. | |
1141 | * Generally, the larger the better; as the number of slots per level of the | |
1142 | * tree increases, the less tall the tree needs to be. But that needs to be | |
1143 | * balanced against the memory consumption of each node. On a 64-bit system, | |
1144 | * xa_node is currently 576 bytes, and we get 7 of them per 4kB page. If we | |
1145 | * doubled the number of slots per node, we'd get only 3 nodes per 4kB page. | |
1146 | */ | |
1147 | #ifndef XA_CHUNK_SHIFT | |
b3e90f37 | 1148 | #define XA_CHUNK_SHIFT (IS_ENABLED(CONFIG_BASE_SMALL) ? 4 : 6) |
02c02bf1 MW |
1149 | #endif |
1150 | #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) | |
1151 | #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) | |
01959dfe | 1152 | #define XA_MAX_MARKS 3 |
ccde70f4 | 1153 | #define XA_MARK_LONGS BITS_TO_LONGS(XA_CHUNK_SIZE) |
01959dfe MW |
1154 | |
1155 | /* | |
1156 | * @count is the count of every non-NULL element in the ->slots array | |
1157 | * whether that is a value entry, a retry entry, a user pointer, | |
1158 | * a sibling entry or a pointer to the next level of the tree. | |
1159 | * @nr_values is the count of every element in ->slots which is | |
1160 | * either a value entry or a sibling of a value entry. | |
1161 | */ | |
1162 | struct xa_node { | |
1163 | unsigned char shift; /* Bits remaining in each slot */ | |
1164 | unsigned char offset; /* Slot offset in parent */ | |
1165 | unsigned char count; /* Total entry count */ | |
1166 | unsigned char nr_values; /* Value entry count */ | |
1167 | struct xa_node __rcu *parent; /* NULL at top of tree */ | |
1168 | struct xarray *array; /* The array we belong to */ | |
1169 | union { | |
1170 | struct list_head private_list; /* For tree user */ | |
1171 | struct rcu_head rcu_head; /* Used when freeing node */ | |
1172 | }; | |
1173 | void __rcu *slots[XA_CHUNK_SIZE]; | |
1174 | union { | |
1175 | unsigned long tags[XA_MAX_MARKS][XA_MARK_LONGS]; | |
1176 | unsigned long marks[XA_MAX_MARKS][XA_MARK_LONGS]; | |
1177 | }; | |
1178 | }; | |
02c02bf1 | 1179 | |
ad3d6c72 MW |
1180 | void xa_dump(const struct xarray *); |
1181 | void xa_dump_node(const struct xa_node *); | |
1182 | ||
1183 | #ifdef XA_DEBUG | |
1184 | #define XA_BUG_ON(xa, x) do { \ | |
1185 | if (x) { \ | |
1186 | xa_dump(xa); \ | |
1187 | BUG(); \ | |
1188 | } \ | |
1189 | } while (0) | |
1190 | #define XA_NODE_BUG_ON(node, x) do { \ | |
1191 | if (x) { \ | |
1192 | if (node) xa_dump_node(node); \ | |
1193 | BUG(); \ | |
1194 | } \ | |
1195 | } while (0) | |
1196 | #else | |
1197 | #define XA_BUG_ON(xa, x) do { } while (0) | |
1198 | #define XA_NODE_BUG_ON(node, x) do { } while (0) | |
1199 | #endif | |
1200 | ||
1201 | /* Private */ | |
1202 | static inline void *xa_head(const struct xarray *xa) | |
1203 | { | |
1204 | return rcu_dereference_check(xa->xa_head, | |
1205 | lockdep_is_held(&xa->xa_lock)); | |
1206 | } | |
1207 | ||
1208 | /* Private */ | |
1209 | static inline void *xa_head_locked(const struct xarray *xa) | |
1210 | { | |
1211 | return rcu_dereference_protected(xa->xa_head, | |
1212 | lockdep_is_held(&xa->xa_lock)); | |
1213 | } | |
1214 | ||
1215 | /* Private */ | |
1216 | static inline void *xa_entry(const struct xarray *xa, | |
1217 | const struct xa_node *node, unsigned int offset) | |
1218 | { | |
1219 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); | |
1220 | return rcu_dereference_check(node->slots[offset], | |
1221 | lockdep_is_held(&xa->xa_lock)); | |
1222 | } | |
1223 | ||
1224 | /* Private */ | |
1225 | static inline void *xa_entry_locked(const struct xarray *xa, | |
1226 | const struct xa_node *node, unsigned int offset) | |
1227 | { | |
1228 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); | |
1229 | return rcu_dereference_protected(node->slots[offset], | |
1230 | lockdep_is_held(&xa->xa_lock)); | |
1231 | } | |
1232 | ||
9b89a035 MW |
1233 | /* Private */ |
1234 | static inline struct xa_node *xa_parent(const struct xarray *xa, | |
1235 | const struct xa_node *node) | |
1236 | { | |
1237 | return rcu_dereference_check(node->parent, | |
1238 | lockdep_is_held(&xa->xa_lock)); | |
1239 | } | |
1240 | ||
1241 | /* Private */ | |
1242 | static inline struct xa_node *xa_parent_locked(const struct xarray *xa, | |
1243 | const struct xa_node *node) | |
1244 | { | |
1245 | return rcu_dereference_protected(node->parent, | |
1246 | lockdep_is_held(&xa->xa_lock)); | |
1247 | } | |
1248 | ||
58d6ea30 MW |
1249 | /* Private */ |
1250 | static inline void *xa_mk_node(const struct xa_node *node) | |
1251 | { | |
1252 | return (void *)((unsigned long)node | 2); | |
1253 | } | |
1254 | ||
ad3d6c72 MW |
1255 | /* Private */ |
1256 | static inline struct xa_node *xa_to_node(const void *entry) | |
1257 | { | |
1258 | return (struct xa_node *)((unsigned long)entry - 2); | |
1259 | } | |
1260 | ||
02c02bf1 MW |
1261 | /* Private */ |
1262 | static inline bool xa_is_node(const void *entry) | |
1263 | { | |
1264 | return xa_is_internal(entry) && (unsigned long)entry > 4096; | |
1265 | } | |
1266 | ||
1267 | /* Private */ | |
1268 | static inline void *xa_mk_sibling(unsigned int offset) | |
1269 | { | |
1270 | return xa_mk_internal(offset); | |
1271 | } | |
1272 | ||
1273 | /* Private */ | |
1274 | static inline unsigned long xa_to_sibling(const void *entry) | |
1275 | { | |
1276 | return xa_to_internal(entry); | |
1277 | } | |
1278 | ||
1279 | /** | |
1280 | * xa_is_sibling() - Is the entry a sibling entry? | |
1281 | * @entry: Entry retrieved from the XArray | |
1282 | * | |
1283 | * Return: %true if the entry is a sibling entry. | |
1284 | */ | |
1285 | static inline bool xa_is_sibling(const void *entry) | |
1286 | { | |
1287 | return IS_ENABLED(CONFIG_XARRAY_MULTI) && xa_is_internal(entry) && | |
1288 | (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1)); | |
1289 | } | |
1290 | ||
76b4e529 | 1291 | #define XA_RETRY_ENTRY xa_mk_internal(256) |
02c02bf1 | 1292 | |
ad3d6c72 MW |
1293 | /** |
1294 | * xa_is_retry() - Is the entry a retry entry? | |
1295 | * @entry: Entry retrieved from the XArray | |
1296 | * | |
1297 | * Return: %true if the entry is a retry entry. | |
1298 | */ | |
1299 | static inline bool xa_is_retry(const void *entry) | |
1300 | { | |
1301 | return unlikely(entry == XA_RETRY_ENTRY); | |
1302 | } | |
1303 | ||
76b4e529 MW |
1304 | /** |
1305 | * xa_is_advanced() - Is the entry only permitted for the advanced API? | |
1306 | * @entry: Entry to be stored in the XArray. | |
1307 | * | |
1308 | * Return: %true if the entry cannot be stored by the normal API. | |
1309 | */ | |
1310 | static inline bool xa_is_advanced(const void *entry) | |
1311 | { | |
1312 | return xa_is_internal(entry) && (entry <= XA_RETRY_ENTRY); | |
1313 | } | |
1314 | ||
ad3d6c72 MW |
1315 | /** |
1316 | * typedef xa_update_node_t - A callback function from the XArray. | |
1317 | * @node: The node which is being processed | |
1318 | * | |
1319 | * This function is called every time the XArray updates the count of | |
1320 | * present and value entries in a node. It allows advanced users to | |
1321 | * maintain the private_list in the node. | |
1322 | * | |
1323 | * Context: The xa_lock is held and interrupts may be disabled. | |
1324 | * Implementations should not drop the xa_lock, nor re-enable | |
1325 | * interrupts. | |
1326 | */ | |
1327 | typedef void (*xa_update_node_t)(struct xa_node *node); | |
1328 | ||
f82cd2f0 MWO |
1329 | void xa_delete_node(struct xa_node *, xa_update_node_t); |
1330 | ||
ad3d6c72 MW |
1331 | /* |
1332 | * The xa_state is opaque to its users. It contains various different pieces | |
1333 | * of state involved in the current operation on the XArray. It should be | |
1334 | * declared on the stack and passed between the various internal routines. | |
1335 | * The various elements in it should not be accessed directly, but only | |
1336 | * through the provided accessor functions. The below documentation is for | |
1337 | * the benefit of those working on the code, not for users of the XArray. | |
1338 | * | |
1339 | * @xa_node usually points to the xa_node containing the slot we're operating | |
1340 | * on (and @xa_offset is the offset in the slots array). If there is a | |
1341 | * single entry in the array at index 0, there are no allocated xa_nodes to | |
1342 | * point to, and so we store %NULL in @xa_node. @xa_node is set to | |
1343 | * the value %XAS_RESTART if the xa_state is not walked to the correct | |
1344 | * position in the tree of nodes for this operation. If an error occurs | |
1345 | * during an operation, it is set to an %XAS_ERROR value. If we run off the | |
1346 | * end of the allocated nodes, it is set to %XAS_BOUNDS. | |
1347 | */ | |
1348 | struct xa_state { | |
1349 | struct xarray *xa; | |
1350 | unsigned long xa_index; | |
1351 | unsigned char xa_shift; | |
1352 | unsigned char xa_sibs; | |
1353 | unsigned char xa_offset; | |
1354 | unsigned char xa_pad; /* Helps gcc generate better code */ | |
1355 | struct xa_node *xa_node; | |
1356 | struct xa_node *xa_alloc; | |
1357 | xa_update_node_t xa_update; | |
9bbdc0f3 | 1358 | struct list_lru *xa_lru; |
ad3d6c72 MW |
1359 | }; |
1360 | ||
1361 | /* | |
1362 | * We encode errnos in the xas->xa_node. If an error has happened, we need to | |
1363 | * drop the lock to fix it, and once we've done so the xa_state is invalid. | |
1364 | */ | |
1365 | #define XA_ERROR(errno) ((struct xa_node *)(((unsigned long)errno << 2) | 2UL)) | |
1366 | #define XAS_BOUNDS ((struct xa_node *)1UL) | |
1367 | #define XAS_RESTART ((struct xa_node *)3UL) | |
1368 | ||
1369 | #define __XA_STATE(array, index, shift, sibs) { \ | |
1370 | .xa = array, \ | |
1371 | .xa_index = index, \ | |
1372 | .xa_shift = shift, \ | |
1373 | .xa_sibs = sibs, \ | |
1374 | .xa_offset = 0, \ | |
1375 | .xa_pad = 0, \ | |
1376 | .xa_node = XAS_RESTART, \ | |
1377 | .xa_alloc = NULL, \ | |
9bbdc0f3 MS |
1378 | .xa_update = NULL, \ |
1379 | .xa_lru = NULL, \ | |
ad3d6c72 MW |
1380 | } |
1381 | ||
1382 | /** | |
1383 | * XA_STATE() - Declare an XArray operation state. | |
1384 | * @name: Name of this operation state (usually xas). | |
1385 | * @array: Array to operate on. | |
1386 | * @index: Initial index of interest. | |
1387 | * | |
1388 | * Declare and initialise an xa_state on the stack. | |
1389 | */ | |
1390 | #define XA_STATE(name, array, index) \ | |
1391 | struct xa_state name = __XA_STATE(array, index, 0, 0) | |
1392 | ||
1393 | /** | |
1394 | * XA_STATE_ORDER() - Declare an XArray operation state. | |
1395 | * @name: Name of this operation state (usually xas). | |
1396 | * @array: Array to operate on. | |
1397 | * @index: Initial index of interest. | |
1398 | * @order: Order of entry. | |
1399 | * | |
1400 | * Declare and initialise an xa_state on the stack. This variant of | |
1401 | * XA_STATE() allows you to specify the 'order' of the element you | |
1402 | * want to operate on.` | |
1403 | */ | |
1404 | #define XA_STATE_ORDER(name, array, index, order) \ | |
1405 | struct xa_state name = __XA_STATE(array, \ | |
1406 | (index >> order) << order, \ | |
1407 | order - (order % XA_CHUNK_SHIFT), \ | |
1408 | (1U << (order % XA_CHUNK_SHIFT)) - 1) | |
1409 | ||
1410 | #define xas_marked(xas, mark) xa_marked((xas)->xa, (mark)) | |
1411 | #define xas_trylock(xas) xa_trylock((xas)->xa) | |
1412 | #define xas_lock(xas) xa_lock((xas)->xa) | |
1413 | #define xas_unlock(xas) xa_unlock((xas)->xa) | |
1414 | #define xas_lock_bh(xas) xa_lock_bh((xas)->xa) | |
1415 | #define xas_unlock_bh(xas) xa_unlock_bh((xas)->xa) | |
1416 | #define xas_lock_irq(xas) xa_lock_irq((xas)->xa) | |
1417 | #define xas_unlock_irq(xas) xa_unlock_irq((xas)->xa) | |
1418 | #define xas_lock_irqsave(xas, flags) \ | |
1419 | xa_lock_irqsave((xas)->xa, flags) | |
1420 | #define xas_unlock_irqrestore(xas, flags) \ | |
1421 | xa_unlock_irqrestore((xas)->xa, flags) | |
1422 | ||
1423 | /** | |
1424 | * xas_error() - Return an errno stored in the xa_state. | |
1425 | * @xas: XArray operation state. | |
1426 | * | |
1427 | * Return: 0 if no error has been noted. A negative errno if one has. | |
1428 | */ | |
1429 | static inline int xas_error(const struct xa_state *xas) | |
1430 | { | |
1431 | return xa_err(xas->xa_node); | |
1432 | } | |
1433 | ||
1434 | /** | |
1435 | * xas_set_err() - Note an error in the xa_state. | |
1436 | * @xas: XArray operation state. | |
1437 | * @err: Negative error number. | |
1438 | * | |
1439 | * Only call this function with a negative @err; zero or positive errors | |
1440 | * will probably not behave the way you think they should. If you want | |
1441 | * to clear the error from an xa_state, use xas_reset(). | |
1442 | */ | |
1443 | static inline void xas_set_err(struct xa_state *xas, long err) | |
1444 | { | |
1445 | xas->xa_node = XA_ERROR(err); | |
1446 | } | |
1447 | ||
1448 | /** | |
1449 | * xas_invalid() - Is the xas in a retry or error state? | |
1450 | * @xas: XArray operation state. | |
1451 | * | |
1452 | * Return: %true if the xas cannot be used for operations. | |
1453 | */ | |
1454 | static inline bool xas_invalid(const struct xa_state *xas) | |
1455 | { | |
1456 | return (unsigned long)xas->xa_node & 3; | |
1457 | } | |
1458 | ||
1459 | /** | |
1460 | * xas_valid() - Is the xas a valid cursor into the array? | |
1461 | * @xas: XArray operation state. | |
1462 | * | |
1463 | * Return: %true if the xas can be used for operations. | |
1464 | */ | |
1465 | static inline bool xas_valid(const struct xa_state *xas) | |
1466 | { | |
1467 | return !xas_invalid(xas); | |
1468 | } | |
1469 | ||
2264f513 MW |
1470 | /** |
1471 | * xas_is_node() - Does the xas point to a node? | |
1472 | * @xas: XArray operation state. | |
1473 | * | |
1474 | * Return: %true if the xas currently references a node. | |
1475 | */ | |
1476 | static inline bool xas_is_node(const struct xa_state *xas) | |
1477 | { | |
1478 | return xas_valid(xas) && xas->xa_node; | |
1479 | } | |
1480 | ||
9b89a035 MW |
1481 | /* True if the pointer is something other than a node */ |
1482 | static inline bool xas_not_node(struct xa_node *node) | |
1483 | { | |
1484 | return ((unsigned long)node & 3) || !node; | |
1485 | } | |
1486 | ||
64d3e9a9 MW |
1487 | /* True if the node represents RESTART or an error */ |
1488 | static inline bool xas_frozen(struct xa_node *node) | |
1489 | { | |
1490 | return (unsigned long)node & 2; | |
1491 | } | |
1492 | ||
58d6ea30 MW |
1493 | /* True if the node represents head-of-tree, RESTART or BOUNDS */ |
1494 | static inline bool xas_top(struct xa_node *node) | |
1495 | { | |
1496 | return node <= XAS_RESTART; | |
1497 | } | |
1498 | ||
ad3d6c72 MW |
1499 | /** |
1500 | * xas_reset() - Reset an XArray operation state. | |
1501 | * @xas: XArray operation state. | |
1502 | * | |
1503 | * Resets the error or walk state of the @xas so future walks of the | |
1504 | * array will start from the root. Use this if you have dropped the | |
1505 | * xarray lock and want to reuse the xa_state. | |
1506 | * | |
1507 | * Context: Any context. | |
1508 | */ | |
1509 | static inline void xas_reset(struct xa_state *xas) | |
1510 | { | |
1511 | xas->xa_node = XAS_RESTART; | |
1512 | } | |
1513 | ||
1514 | /** | |
1515 | * xas_retry() - Retry the operation if appropriate. | |
1516 | * @xas: XArray operation state. | |
1517 | * @entry: Entry from xarray. | |
1518 | * | |
1519 | * The advanced functions may sometimes return an internal entry, such as | |
1520 | * a retry entry or a zero entry. This function sets up the @xas to restart | |
1521 | * the walk from the head of the array if needed. | |
1522 | * | |
1523 | * Context: Any context. | |
1524 | * Return: true if the operation needs to be retried. | |
1525 | */ | |
1526 | static inline bool xas_retry(struct xa_state *xas, const void *entry) | |
1527 | { | |
9f14d4f1 MW |
1528 | if (xa_is_zero(entry)) |
1529 | return true; | |
ad3d6c72 MW |
1530 | if (!xa_is_retry(entry)) |
1531 | return false; | |
1532 | xas_reset(xas); | |
1533 | return true; | |
1534 | } | |
1535 | ||
1536 | void *xas_load(struct xa_state *); | |
58d6ea30 | 1537 | void *xas_store(struct xa_state *, void *entry); |
b803b428 | 1538 | void *xas_find(struct xa_state *, unsigned long max); |
4e99d4e9 | 1539 | void *xas_find_conflict(struct xa_state *); |
ad3d6c72 | 1540 | |
9b89a035 MW |
1541 | bool xas_get_mark(const struct xa_state *, xa_mark_t); |
1542 | void xas_set_mark(const struct xa_state *, xa_mark_t); | |
1543 | void xas_clear_mark(const struct xa_state *, xa_mark_t); | |
b803b428 | 1544 | void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t); |
58d6ea30 MW |
1545 | void xas_init_marks(const struct xa_state *); |
1546 | ||
1547 | bool xas_nomem(struct xa_state *, gfp_t); | |
69a37a8b | 1548 | void xas_destroy(struct xa_state *); |
b803b428 | 1549 | void xas_pause(struct xa_state *); |
9b89a035 | 1550 | |
2264f513 MW |
1551 | void xas_create_range(struct xa_state *); |
1552 | ||
57417ceb MWO |
1553 | #ifdef CONFIG_XARRAY_MULTI |
1554 | int xa_get_order(struct xarray *, unsigned long index); | |
a4864671 | 1555 | int xas_get_order(struct xa_state *xas); |
8fc75643 MWO |
1556 | void xas_split(struct xa_state *, void *entry, unsigned int order); |
1557 | void xas_split_alloc(struct xa_state *, void *entry, unsigned int order, gfp_t); | |
57417ceb MWO |
1558 | #else |
1559 | static inline int xa_get_order(struct xarray *xa, unsigned long index) | |
1560 | { | |
1561 | return 0; | |
1562 | } | |
8fc75643 | 1563 | |
a4864671 KS |
1564 | static inline int xas_get_order(struct xa_state *xas) |
1565 | { | |
1566 | return 0; | |
1567 | } | |
1568 | ||
8fc75643 MWO |
1569 | static inline void xas_split(struct xa_state *xas, void *entry, |
1570 | unsigned int order) | |
1571 | { | |
1572 | xas_store(xas, entry); | |
1573 | } | |
1574 | ||
1575 | static inline void xas_split_alloc(struct xa_state *xas, void *entry, | |
1576 | unsigned int order, gfp_t gfp) | |
1577 | { | |
1578 | } | |
57417ceb MWO |
1579 | #endif |
1580 | ||
ad3d6c72 MW |
1581 | /** |
1582 | * xas_reload() - Refetch an entry from the xarray. | |
1583 | * @xas: XArray operation state. | |
1584 | * | |
1585 | * Use this function to check that a previously loaded entry still has | |
1586 | * the same value. This is useful for the lockless pagecache lookup where | |
1587 | * we walk the array with only the RCU lock to protect us, lock the page, | |
1588 | * then check that the page hasn't moved since we looked it up. | |
1589 | * | |
1590 | * The caller guarantees that @xas is still valid. If it may be in an | |
1591 | * error or restart state, call xas_load() instead. | |
1592 | * | |
1593 | * Return: The entry at this location in the xarray. | |
1594 | */ | |
1595 | static inline void *xas_reload(struct xa_state *xas) | |
1596 | { | |
1597 | struct xa_node *node = xas->xa_node; | |
ca7b639e MWO |
1598 | void *entry; |
1599 | char offset; | |
1600 | ||
1601 | if (!node) | |
1602 | return xa_head(xas->xa); | |
1603 | if (IS_ENABLED(CONFIG_XARRAY_MULTI)) { | |
1604 | offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK; | |
1605 | entry = xa_entry(xas->xa, node, offset); | |
1606 | if (!xa_is_sibling(entry)) | |
1607 | return entry; | |
1608 | offset = xa_to_sibling(entry); | |
1609 | } else { | |
1610 | offset = xas->xa_offset; | |
1611 | } | |
1612 | return xa_entry(xas->xa, node, offset); | |
ad3d6c72 MW |
1613 | } |
1614 | ||
58d6ea30 MW |
1615 | /** |
1616 | * xas_set() - Set up XArray operation state for a different index. | |
1617 | * @xas: XArray operation state. | |
1618 | * @index: New index into the XArray. | |
1619 | * | |
1620 | * Move the operation state to refer to a different index. This will | |
1621 | * have the effect of starting a walk from the top; see xas_next() | |
1622 | * to move to an adjacent index. | |
1623 | */ | |
1624 | static inline void xas_set(struct xa_state *xas, unsigned long index) | |
1625 | { | |
1626 | xas->xa_index = index; | |
1627 | xas->xa_node = XAS_RESTART; | |
1628 | } | |
1629 | ||
25a8de7f MWO |
1630 | /** |
1631 | * xas_advance() - Skip over sibling entries. | |
1632 | * @xas: XArray operation state. | |
1633 | * @index: Index of last sibling entry. | |
1634 | * | |
1635 | * Move the operation state to refer to the last sibling entry. | |
1636 | * This is useful for loops that normally want to see sibling | |
1637 | * entries but sometimes want to skip them. Use xas_set() if you | |
1638 | * want to move to an index which is not part of this entry. | |
1639 | */ | |
1640 | static inline void xas_advance(struct xa_state *xas, unsigned long index) | |
1641 | { | |
1642 | unsigned char shift = xas_is_node(xas) ? xas->xa_node->shift : 0; | |
1643 | ||
1644 | xas->xa_index = index; | |
1645 | xas->xa_offset = (index >> shift) & XA_CHUNK_MASK; | |
1646 | } | |
1647 | ||
58d6ea30 MW |
1648 | /** |
1649 | * xas_set_order() - Set up XArray operation state for a multislot entry. | |
1650 | * @xas: XArray operation state. | |
1651 | * @index: Target of the operation. | |
1652 | * @order: Entry occupies 2^@order indices. | |
1653 | */ | |
1654 | static inline void xas_set_order(struct xa_state *xas, unsigned long index, | |
1655 | unsigned int order) | |
1656 | { | |
1657 | #ifdef CONFIG_XARRAY_MULTI | |
1658 | xas->xa_index = order < BITS_PER_LONG ? (index >> order) << order : 0; | |
1659 | xas->xa_shift = order - (order % XA_CHUNK_SHIFT); | |
1660 | xas->xa_sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; | |
1661 | xas->xa_node = XAS_RESTART; | |
1662 | #else | |
1663 | BUG_ON(order > 0); | |
1664 | xas_set(xas, index); | |
1665 | #endif | |
1666 | } | |
1667 | ||
1668 | /** | |
1669 | * xas_set_update() - Set up XArray operation state for a callback. | |
1670 | * @xas: XArray operation state. | |
1671 | * @update: Function to call when updating a node. | |
1672 | * | |
1673 | * The XArray can notify a caller after it has updated an xa_node. | |
5649d113 YY |
1674 | * This is advanced functionality and is only needed by the page |
1675 | * cache and swap cache. | |
58d6ea30 MW |
1676 | */ |
1677 | static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) | |
1678 | { | |
1679 | xas->xa_update = update; | |
1680 | } | |
1681 | ||
9bbdc0f3 MS |
1682 | static inline void xas_set_lru(struct xa_state *xas, struct list_lru *lru) |
1683 | { | |
1684 | xas->xa_lru = lru; | |
1685 | } | |
1686 | ||
b803b428 MW |
1687 | /** |
1688 | * xas_next_entry() - Advance iterator to next present entry. | |
1689 | * @xas: XArray operation state. | |
1690 | * @max: Highest index to return. | |
1691 | * | |
1692 | * xas_next_entry() is an inline function to optimise xarray traversal for | |
1693 | * speed. It is equivalent to calling xas_find(), and will call xas_find() | |
1694 | * for all the hard cases. | |
1695 | * | |
1696 | * Return: The next present entry after the one currently referred to by @xas. | |
1697 | */ | |
1698 | static inline void *xas_next_entry(struct xa_state *xas, unsigned long max) | |
1699 | { | |
1700 | struct xa_node *node = xas->xa_node; | |
1701 | void *entry; | |
1702 | ||
1703 | if (unlikely(xas_not_node(node) || node->shift || | |
1704 | xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK))) | |
1705 | return xas_find(xas, max); | |
1706 | ||
1707 | do { | |
1708 | if (unlikely(xas->xa_index >= max)) | |
1709 | return xas_find(xas, max); | |
1710 | if (unlikely(xas->xa_offset == XA_CHUNK_MASK)) | |
1711 | return xas_find(xas, max); | |
1712 | entry = xa_entry(xas->xa, node, xas->xa_offset + 1); | |
1713 | if (unlikely(xa_is_internal(entry))) | |
1714 | return xas_find(xas, max); | |
1715 | xas->xa_offset++; | |
1716 | xas->xa_index++; | |
1717 | } while (!entry); | |
1718 | ||
1719 | return entry; | |
1720 | } | |
1721 | ||
1722 | /* Private */ | |
1723 | static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, | |
1724 | xa_mark_t mark) | |
1725 | { | |
1726 | unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark]; | |
1727 | unsigned int offset = xas->xa_offset; | |
1728 | ||
1729 | if (advance) | |
1730 | offset++; | |
1731 | if (XA_CHUNK_SIZE == BITS_PER_LONG) { | |
1732 | if (offset < XA_CHUNK_SIZE) { | |
1733 | unsigned long data = *addr & (~0UL << offset); | |
1734 | if (data) | |
1735 | return __ffs(data); | |
1736 | } | |
1737 | return XA_CHUNK_SIZE; | |
1738 | } | |
1739 | ||
1740 | return find_next_bit(addr, XA_CHUNK_SIZE, offset); | |
1741 | } | |
1742 | ||
1743 | /** | |
1744 | * xas_next_marked() - Advance iterator to next marked entry. | |
1745 | * @xas: XArray operation state. | |
1746 | * @max: Highest index to return. | |
1747 | * @mark: Mark to search for. | |
1748 | * | |
1749 | * xas_next_marked() is an inline function to optimise xarray traversal for | |
1750 | * speed. It is equivalent to calling xas_find_marked(), and will call | |
1751 | * xas_find_marked() for all the hard cases. | |
1752 | * | |
1753 | * Return: The next marked entry after the one currently referred to by @xas. | |
1754 | */ | |
1755 | static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, | |
1756 | xa_mark_t mark) | |
1757 | { | |
1758 | struct xa_node *node = xas->xa_node; | |
7e934cf5 | 1759 | void *entry; |
b803b428 MW |
1760 | unsigned int offset; |
1761 | ||
1762 | if (unlikely(xas_not_node(node) || node->shift)) | |
1763 | return xas_find_marked(xas, max, mark); | |
1764 | offset = xas_find_chunk(xas, true, mark); | |
1765 | xas->xa_offset = offset; | |
1766 | xas->xa_index = (xas->xa_index & ~XA_CHUNK_MASK) + offset; | |
1767 | if (xas->xa_index > max) | |
1768 | return NULL; | |
1769 | if (offset == XA_CHUNK_SIZE) | |
1770 | return xas_find_marked(xas, max, mark); | |
7e934cf5 MWO |
1771 | entry = xa_entry(xas->xa, node, offset); |
1772 | if (!entry) | |
1773 | return xas_find_marked(xas, max, mark); | |
1774 | return entry; | |
b803b428 MW |
1775 | } |
1776 | ||
1777 | /* | |
1778 | * If iterating while holding a lock, drop the lock and reschedule | |
1779 | * every %XA_CHECK_SCHED loops. | |
1780 | */ | |
1781 | enum { | |
1782 | XA_CHECK_SCHED = 4096, | |
1783 | }; | |
1784 | ||
1785 | /** | |
1786 | * xas_for_each() - Iterate over a range of an XArray. | |
1787 | * @xas: XArray operation state. | |
1788 | * @entry: Entry retrieved from the array. | |
1789 | * @max: Maximum index to retrieve from array. | |
1790 | * | |
1791 | * The loop body will be executed for each entry present in the xarray | |
1792 | * between the current xas position and @max. @entry will be set to | |
1793 | * the entry retrieved from the xarray. It is safe to delete entries | |
1794 | * from the array in the loop body. You should hold either the RCU lock | |
1795 | * or the xa_lock while iterating. If you need to drop the lock, call | |
1796 | * xas_pause() first. | |
1797 | */ | |
1798 | #define xas_for_each(xas, entry, max) \ | |
1799 | for (entry = xas_find(xas, max); entry; \ | |
1800 | entry = xas_next_entry(xas, max)) | |
1801 | ||
1802 | /** | |
1803 | * xas_for_each_marked() - Iterate over a range of an XArray. | |
1804 | * @xas: XArray operation state. | |
1805 | * @entry: Entry retrieved from the array. | |
1806 | * @max: Maximum index to retrieve from array. | |
1807 | * @mark: Mark to search for. | |
1808 | * | |
1809 | * The loop body will be executed for each marked entry in the xarray | |
1810 | * between the current xas position and @max. @entry will be set to | |
1811 | * the entry retrieved from the xarray. It is safe to delete entries | |
1812 | * from the array in the loop body. You should hold either the RCU lock | |
1813 | * or the xa_lock while iterating. If you need to drop the lock, call | |
1814 | * xas_pause() first. | |
1815 | */ | |
1816 | #define xas_for_each_marked(xas, entry, max, mark) \ | |
1817 | for (entry = xas_find_marked(xas, max, mark); entry; \ | |
1818 | entry = xas_next_marked(xas, max, mark)) | |
1819 | ||
4e99d4e9 MW |
1820 | /** |
1821 | * xas_for_each_conflict() - Iterate over a range of an XArray. | |
1822 | * @xas: XArray operation state. | |
1823 | * @entry: Entry retrieved from the array. | |
1824 | * | |
8446466c MWO |
1825 | * The loop body will be executed for each entry in the XArray that |
1826 | * lies within the range specified by @xas. If the loop terminates | |
1827 | * normally, @entry will be %NULL. The user may break out of the loop, | |
1828 | * which will leave @entry set to the conflicting entry. The caller | |
1829 | * may also call xa_set_err() to exit the loop while setting an error | |
1830 | * to record the reason. | |
4e99d4e9 MW |
1831 | */ |
1832 | #define xas_for_each_conflict(xas, entry) \ | |
1833 | while ((entry = xas_find_conflict(xas))) | |
1834 | ||
64d3e9a9 MW |
1835 | void *__xas_next(struct xa_state *); |
1836 | void *__xas_prev(struct xa_state *); | |
1837 | ||
1838 | /** | |
1839 | * xas_prev() - Move iterator to previous index. | |
1840 | * @xas: XArray operation state. | |
1841 | * | |
1842 | * If the @xas was in an error state, it will remain in an error state | |
1843 | * and this function will return %NULL. If the @xas has never been walked, | |
1844 | * it will have the effect of calling xas_load(). Otherwise one will be | |
1845 | * subtracted from the index and the state will be walked to the correct | |
1846 | * location in the array for the next operation. | |
1847 | * | |
1848 | * If the iterator was referencing index 0, this function wraps | |
1849 | * around to %ULONG_MAX. | |
1850 | * | |
1851 | * Return: The entry at the new index. This may be %NULL or an internal | |
1852 | * entry. | |
1853 | */ | |
1854 | static inline void *xas_prev(struct xa_state *xas) | |
1855 | { | |
1856 | struct xa_node *node = xas->xa_node; | |
1857 | ||
1858 | if (unlikely(xas_not_node(node) || node->shift || | |
1859 | xas->xa_offset == 0)) | |
1860 | return __xas_prev(xas); | |
1861 | ||
1862 | xas->xa_index--; | |
1863 | xas->xa_offset--; | |
1864 | return xa_entry(xas->xa, node, xas->xa_offset); | |
1865 | } | |
1866 | ||
1867 | /** | |
1868 | * xas_next() - Move state to next index. | |
1869 | * @xas: XArray operation state. | |
1870 | * | |
1871 | * If the @xas was in an error state, it will remain in an error state | |
1872 | * and this function will return %NULL. If the @xas has never been walked, | |
1873 | * it will have the effect of calling xas_load(). Otherwise one will be | |
1874 | * added to the index and the state will be walked to the correct | |
1875 | * location in the array for the next operation. | |
1876 | * | |
1877 | * If the iterator was referencing index %ULONG_MAX, this function wraps | |
1878 | * around to 0. | |
1879 | * | |
1880 | * Return: The entry at the new index. This may be %NULL or an internal | |
1881 | * entry. | |
1882 | */ | |
1883 | static inline void *xas_next(struct xa_state *xas) | |
1884 | { | |
1885 | struct xa_node *node = xas->xa_node; | |
1886 | ||
1887 | if (unlikely(xas_not_node(node) || node->shift || | |
1888 | xas->xa_offset == XA_CHUNK_MASK)) | |
1889 | return __xas_next(xas); | |
1890 | ||
1891 | xas->xa_index++; | |
1892 | xas->xa_offset++; | |
1893 | return xa_entry(xas->xa, node, xas->xa_offset); | |
1894 | } | |
1895 | ||
f6bb2a2c | 1896 | #endif /* _LINUX_XARRAY_H */ |