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Commit | Line | Data |
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2e0ab8ca MT |
1 | /* |
2 | * Definitions for the 'struct ptr_ring' datastructure. | |
3 | * | |
4 | * Author: | |
5 | * Michael S. Tsirkin <mst@redhat.com> | |
6 | * | |
7 | * Copyright (C) 2016 Red Hat, Inc. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation; either version 2 of the License, or (at your | |
12 | * option) any later version. | |
13 | * | |
14 | * This is a limited-size FIFO maintaining pointers in FIFO order, with | |
15 | * one CPU producing entries and another consuming entries from a FIFO. | |
16 | * | |
17 | * This implementation tries to minimize cache-contention when there is a | |
18 | * single producer and a single consumer CPU. | |
19 | */ | |
20 | ||
21 | #ifndef _LINUX_PTR_RING_H | |
22 | #define _LINUX_PTR_RING_H 1 | |
23 | ||
24 | #ifdef __KERNEL__ | |
25 | #include <linux/spinlock.h> | |
26 | #include <linux/cache.h> | |
27 | #include <linux/types.h> | |
28 | #include <linux/compiler.h> | |
2e0ab8ca MT |
29 | #include <linux/slab.h> |
30 | #include <asm/errno.h> | |
31 | #endif | |
32 | ||
33 | struct ptr_ring { | |
34 | int producer ____cacheline_aligned_in_smp; | |
35 | spinlock_t producer_lock; | |
fb9de970 MT |
36 | int consumer_head ____cacheline_aligned_in_smp; /* next valid entry */ |
37 | int consumer_tail; /* next entry to invalidate */ | |
2e0ab8ca MT |
38 | spinlock_t consumer_lock; |
39 | /* Shared consumer/producer data */ | |
40 | /* Read-only by both the producer and the consumer */ | |
41 | int size ____cacheline_aligned_in_smp; /* max entries in queue */ | |
fb9de970 | 42 | int batch; /* number of entries to consume in a batch */ |
2e0ab8ca MT |
43 | void **queue; |
44 | }; | |
45 | ||
46 | /* Note: callers invoking this in a loop must use a compiler barrier, | |
84328342 MT |
47 | * for example cpu_relax(). |
48 | * | |
49 | * NB: this is unlike __ptr_ring_empty in that callers must hold producer_lock: | |
50 | * see e.g. ptr_ring_full. | |
2e0ab8ca MT |
51 | */ |
52 | static inline bool __ptr_ring_full(struct ptr_ring *r) | |
53 | { | |
54 | return r->queue[r->producer]; | |
55 | } | |
56 | ||
57 | static inline bool ptr_ring_full(struct ptr_ring *r) | |
58 | { | |
5d49de53 MT |
59 | bool ret; |
60 | ||
61 | spin_lock(&r->producer_lock); | |
62 | ret = __ptr_ring_full(r); | |
63 | spin_unlock(&r->producer_lock); | |
64 | ||
65 | return ret; | |
66 | } | |
67 | ||
68 | static inline bool ptr_ring_full_irq(struct ptr_ring *r) | |
69 | { | |
70 | bool ret; | |
71 | ||
72 | spin_lock_irq(&r->producer_lock); | |
73 | ret = __ptr_ring_full(r); | |
74 | spin_unlock_irq(&r->producer_lock); | |
75 | ||
76 | return ret; | |
77 | } | |
78 | ||
79 | static inline bool ptr_ring_full_any(struct ptr_ring *r) | |
80 | { | |
81 | unsigned long flags; | |
82 | bool ret; | |
83 | ||
84 | spin_lock_irqsave(&r->producer_lock, flags); | |
85 | ret = __ptr_ring_full(r); | |
86 | spin_unlock_irqrestore(&r->producer_lock, flags); | |
87 | ||
88 | return ret; | |
89 | } | |
90 | ||
91 | static inline bool ptr_ring_full_bh(struct ptr_ring *r) | |
92 | { | |
93 | bool ret; | |
94 | ||
95 | spin_lock_bh(&r->producer_lock); | |
96 | ret = __ptr_ring_full(r); | |
97 | spin_unlock_bh(&r->producer_lock); | |
98 | ||
99 | return ret; | |
2e0ab8ca MT |
100 | } |
101 | ||
102 | /* Note: callers invoking this in a loop must use a compiler barrier, | |
5d49de53 | 103 | * for example cpu_relax(). Callers must hold producer_lock. |
a8ceb5db MT |
104 | * Callers are responsible for making sure pointer that is being queued |
105 | * points to a valid data. | |
2e0ab8ca MT |
106 | */ |
107 | static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr) | |
108 | { | |
982fb490 | 109 | if (unlikely(!r->size) || r->queue[r->producer]) |
2e0ab8ca MT |
110 | return -ENOSPC; |
111 | ||
a8ceb5db MT |
112 | /* Make sure the pointer we are storing points to a valid data. */ |
113 | /* Pairs with smp_read_barrier_depends in __ptr_ring_consume. */ | |
114 | smp_wmb(); | |
115 | ||
a07d29c6 | 116 | WRITE_ONCE(r->queue[r->producer++], ptr); |
2e0ab8ca MT |
117 | if (unlikely(r->producer >= r->size)) |
118 | r->producer = 0; | |
119 | return 0; | |
120 | } | |
121 | ||
e7169530 MT |
122 | /* |
123 | * Note: resize (below) nests producer lock within consumer lock, so if you | |
124 | * consume in interrupt or BH context, you must disable interrupts/BH when | |
125 | * calling this. | |
126 | */ | |
2e0ab8ca MT |
127 | static inline int ptr_ring_produce(struct ptr_ring *r, void *ptr) |
128 | { | |
129 | int ret; | |
130 | ||
131 | spin_lock(&r->producer_lock); | |
132 | ret = __ptr_ring_produce(r, ptr); | |
133 | spin_unlock(&r->producer_lock); | |
134 | ||
135 | return ret; | |
136 | } | |
137 | ||
138 | static inline int ptr_ring_produce_irq(struct ptr_ring *r, void *ptr) | |
139 | { | |
140 | int ret; | |
141 | ||
142 | spin_lock_irq(&r->producer_lock); | |
143 | ret = __ptr_ring_produce(r, ptr); | |
144 | spin_unlock_irq(&r->producer_lock); | |
145 | ||
146 | return ret; | |
147 | } | |
148 | ||
149 | static inline int ptr_ring_produce_any(struct ptr_ring *r, void *ptr) | |
150 | { | |
151 | unsigned long flags; | |
152 | int ret; | |
153 | ||
154 | spin_lock_irqsave(&r->producer_lock, flags); | |
155 | ret = __ptr_ring_produce(r, ptr); | |
156 | spin_unlock_irqrestore(&r->producer_lock, flags); | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | static inline int ptr_ring_produce_bh(struct ptr_ring *r, void *ptr) | |
162 | { | |
163 | int ret; | |
164 | ||
165 | spin_lock_bh(&r->producer_lock); | |
166 | ret = __ptr_ring_produce(r, ptr); | |
167 | spin_unlock_bh(&r->producer_lock); | |
168 | ||
169 | return ret; | |
170 | } | |
171 | ||
2e0ab8ca MT |
172 | static inline void *__ptr_ring_peek(struct ptr_ring *r) |
173 | { | |
982fb490 | 174 | if (likely(r->size)) |
a07d29c6 | 175 | return READ_ONCE(r->queue[r->consumer_head]); |
982fb490 | 176 | return NULL; |
2e0ab8ca MT |
177 | } |
178 | ||
8619d384 MT |
179 | /* |
180 | * Test ring empty status without taking any locks. | |
181 | * | |
182 | * NB: This is only safe to call if ring is never resized. | |
183 | * | |
184 | * However, if some other CPU consumes ring entries at the same time, the value | |
185 | * returned is not guaranteed to be correct. | |
186 | * | |
187 | * In this case - to avoid incorrectly detecting the ring | |
188 | * as empty - the CPU consuming the ring entries is responsible | |
189 | * for either consuming all ring entries until the ring is empty, | |
190 | * or synchronizing with some other CPU and causing it to | |
191 | * re-test __ptr_ring_empty and/or consume the ring enteries | |
192 | * after the synchronization point. | |
193 | * | |
194 | * Note: callers invoking this in a loop must use a compiler barrier, | |
195 | * for example cpu_relax(). | |
196 | */ | |
5d49de53 | 197 | static inline bool __ptr_ring_empty(struct ptr_ring *r) |
2e0ab8ca | 198 | { |
a259df36 MT |
199 | if (likely(r->size)) |
200 | return !r->queue[READ_ONCE(r->consumer_head)]; | |
201 | return true; | |
2e0ab8ca MT |
202 | } |
203 | ||
5d49de53 MT |
204 | static inline bool ptr_ring_empty(struct ptr_ring *r) |
205 | { | |
206 | bool ret; | |
207 | ||
208 | spin_lock(&r->consumer_lock); | |
209 | ret = __ptr_ring_empty(r); | |
210 | spin_unlock(&r->consumer_lock); | |
211 | ||
212 | return ret; | |
213 | } | |
214 | ||
215 | static inline bool ptr_ring_empty_irq(struct ptr_ring *r) | |
216 | { | |
217 | bool ret; | |
218 | ||
219 | spin_lock_irq(&r->consumer_lock); | |
220 | ret = __ptr_ring_empty(r); | |
221 | spin_unlock_irq(&r->consumer_lock); | |
222 | ||
223 | return ret; | |
224 | } | |
225 | ||
226 | static inline bool ptr_ring_empty_any(struct ptr_ring *r) | |
227 | { | |
228 | unsigned long flags; | |
229 | bool ret; | |
230 | ||
231 | spin_lock_irqsave(&r->consumer_lock, flags); | |
232 | ret = __ptr_ring_empty(r); | |
233 | spin_unlock_irqrestore(&r->consumer_lock, flags); | |
234 | ||
235 | return ret; | |
236 | } | |
237 | ||
238 | static inline bool ptr_ring_empty_bh(struct ptr_ring *r) | |
239 | { | |
240 | bool ret; | |
241 | ||
242 | spin_lock_bh(&r->consumer_lock); | |
243 | ret = __ptr_ring_empty(r); | |
244 | spin_unlock_bh(&r->consumer_lock); | |
245 | ||
246 | return ret; | |
247 | } | |
248 | ||
2e0ab8ca MT |
249 | /* Must only be called after __ptr_ring_peek returned !NULL */ |
250 | static inline void __ptr_ring_discard_one(struct ptr_ring *r) | |
251 | { | |
fb9de970 MT |
252 | /* Fundamentally, what we want to do is update consumer |
253 | * index and zero out the entry so producer can reuse it. | |
254 | * Doing it naively at each consume would be as simple as: | |
406de755 MT |
255 | * consumer = r->consumer; |
256 | * r->queue[consumer++] = NULL; | |
257 | * if (unlikely(consumer >= r->size)) | |
258 | * consumer = 0; | |
259 | * r->consumer = consumer; | |
fb9de970 MT |
260 | * but that is suboptimal when the ring is full as producer is writing |
261 | * out new entries in the same cache line. Defer these updates until a | |
262 | * batch of entries has been consumed. | |
263 | */ | |
406de755 MT |
264 | /* Note: we must keep consumer_head valid at all times for __ptr_ring_empty |
265 | * to work correctly. | |
266 | */ | |
267 | int consumer_head = r->consumer_head; | |
268 | int head = consumer_head++; | |
fb9de970 MT |
269 | |
270 | /* Once we have processed enough entries invalidate them in | |
271 | * the ring all at once so producer can reuse their space in the ring. | |
272 | * We also do this when we reach end of the ring - not mandatory | |
273 | * but helps keep the implementation simple. | |
274 | */ | |
406de755 MT |
275 | if (unlikely(consumer_head - r->consumer_tail >= r->batch || |
276 | consumer_head >= r->size)) { | |
fb9de970 MT |
277 | /* Zero out entries in the reverse order: this way we touch the |
278 | * cache line that producer might currently be reading the last; | |
279 | * producer won't make progress and touch other cache lines | |
280 | * besides the first one until we write out all entries. | |
281 | */ | |
282 | while (likely(head >= r->consumer_tail)) | |
283 | r->queue[head--] = NULL; | |
406de755 | 284 | r->consumer_tail = consumer_head; |
fb9de970 | 285 | } |
406de755 MT |
286 | if (unlikely(consumer_head >= r->size)) { |
287 | consumer_head = 0; | |
fb9de970 MT |
288 | r->consumer_tail = 0; |
289 | } | |
a259df36 MT |
290 | /* matching READ_ONCE in __ptr_ring_empty for lockless tests */ |
291 | WRITE_ONCE(r->consumer_head, consumer_head); | |
2e0ab8ca MT |
292 | } |
293 | ||
294 | static inline void *__ptr_ring_consume(struct ptr_ring *r) | |
295 | { | |
296 | void *ptr; | |
297 | ||
e3f9f417 AP |
298 | /* The READ_ONCE in __ptr_ring_peek guarantees that anyone |
299 | * accessing data through the pointer is up to date. Pairs | |
300 | * with smp_wmb in __ptr_ring_produce. | |
301 | */ | |
2e0ab8ca MT |
302 | ptr = __ptr_ring_peek(r); |
303 | if (ptr) | |
304 | __ptr_ring_discard_one(r); | |
305 | ||
306 | return ptr; | |
307 | } | |
308 | ||
728fc8d5 JW |
309 | static inline int __ptr_ring_consume_batched(struct ptr_ring *r, |
310 | void **array, int n) | |
311 | { | |
312 | void *ptr; | |
313 | int i; | |
314 | ||
315 | for (i = 0; i < n; i++) { | |
316 | ptr = __ptr_ring_consume(r); | |
317 | if (!ptr) | |
318 | break; | |
319 | array[i] = ptr; | |
320 | } | |
321 | ||
322 | return i; | |
323 | } | |
324 | ||
e7169530 MT |
325 | /* |
326 | * Note: resize (below) nests producer lock within consumer lock, so if you | |
327 | * call this in interrupt or BH context, you must disable interrupts/BH when | |
328 | * producing. | |
329 | */ | |
2e0ab8ca MT |
330 | static inline void *ptr_ring_consume(struct ptr_ring *r) |
331 | { | |
332 | void *ptr; | |
333 | ||
334 | spin_lock(&r->consumer_lock); | |
335 | ptr = __ptr_ring_consume(r); | |
336 | spin_unlock(&r->consumer_lock); | |
337 | ||
338 | return ptr; | |
339 | } | |
340 | ||
341 | static inline void *ptr_ring_consume_irq(struct ptr_ring *r) | |
342 | { | |
343 | void *ptr; | |
344 | ||
345 | spin_lock_irq(&r->consumer_lock); | |
346 | ptr = __ptr_ring_consume(r); | |
347 | spin_unlock_irq(&r->consumer_lock); | |
348 | ||
349 | return ptr; | |
350 | } | |
351 | ||
352 | static inline void *ptr_ring_consume_any(struct ptr_ring *r) | |
353 | { | |
354 | unsigned long flags; | |
355 | void *ptr; | |
356 | ||
357 | spin_lock_irqsave(&r->consumer_lock, flags); | |
358 | ptr = __ptr_ring_consume(r); | |
359 | spin_unlock_irqrestore(&r->consumer_lock, flags); | |
360 | ||
361 | return ptr; | |
362 | } | |
363 | ||
364 | static inline void *ptr_ring_consume_bh(struct ptr_ring *r) | |
365 | { | |
366 | void *ptr; | |
367 | ||
368 | spin_lock_bh(&r->consumer_lock); | |
369 | ptr = __ptr_ring_consume(r); | |
370 | spin_unlock_bh(&r->consumer_lock); | |
371 | ||
372 | return ptr; | |
373 | } | |
374 | ||
728fc8d5 JW |
375 | static inline int ptr_ring_consume_batched(struct ptr_ring *r, |
376 | void **array, int n) | |
377 | { | |
378 | int ret; | |
379 | ||
380 | spin_lock(&r->consumer_lock); | |
381 | ret = __ptr_ring_consume_batched(r, array, n); | |
382 | spin_unlock(&r->consumer_lock); | |
383 | ||
384 | return ret; | |
385 | } | |
386 | ||
387 | static inline int ptr_ring_consume_batched_irq(struct ptr_ring *r, | |
388 | void **array, int n) | |
389 | { | |
390 | int ret; | |
391 | ||
392 | spin_lock_irq(&r->consumer_lock); | |
393 | ret = __ptr_ring_consume_batched(r, array, n); | |
394 | spin_unlock_irq(&r->consumer_lock); | |
395 | ||
396 | return ret; | |
397 | } | |
398 | ||
399 | static inline int ptr_ring_consume_batched_any(struct ptr_ring *r, | |
400 | void **array, int n) | |
401 | { | |
402 | unsigned long flags; | |
403 | int ret; | |
404 | ||
405 | spin_lock_irqsave(&r->consumer_lock, flags); | |
406 | ret = __ptr_ring_consume_batched(r, array, n); | |
407 | spin_unlock_irqrestore(&r->consumer_lock, flags); | |
408 | ||
409 | return ret; | |
410 | } | |
411 | ||
412 | static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, | |
413 | void **array, int n) | |
414 | { | |
415 | int ret; | |
416 | ||
417 | spin_lock_bh(&r->consumer_lock); | |
418 | ret = __ptr_ring_consume_batched(r, array, n); | |
419 | spin_unlock_bh(&r->consumer_lock); | |
420 | ||
421 | return ret; | |
422 | } | |
423 | ||
2e0ab8ca MT |
424 | /* Cast to structure type and call a function without discarding from FIFO. |
425 | * Function must return a value. | |
426 | * Callers must take consumer_lock. | |
427 | */ | |
428 | #define __PTR_RING_PEEK_CALL(r, f) ((f)(__ptr_ring_peek(r))) | |
429 | ||
430 | #define PTR_RING_PEEK_CALL(r, f) ({ \ | |
431 | typeof((f)(NULL)) __PTR_RING_PEEK_CALL_v; \ | |
432 | \ | |
433 | spin_lock(&(r)->consumer_lock); \ | |
434 | __PTR_RING_PEEK_CALL_v = __PTR_RING_PEEK_CALL(r, f); \ | |
435 | spin_unlock(&(r)->consumer_lock); \ | |
436 | __PTR_RING_PEEK_CALL_v; \ | |
437 | }) | |
438 | ||
439 | #define PTR_RING_PEEK_CALL_IRQ(r, f) ({ \ | |
440 | typeof((f)(NULL)) __PTR_RING_PEEK_CALL_v; \ | |
441 | \ | |
442 | spin_lock_irq(&(r)->consumer_lock); \ | |
443 | __PTR_RING_PEEK_CALL_v = __PTR_RING_PEEK_CALL(r, f); \ | |
444 | spin_unlock_irq(&(r)->consumer_lock); \ | |
445 | __PTR_RING_PEEK_CALL_v; \ | |
446 | }) | |
447 | ||
448 | #define PTR_RING_PEEK_CALL_BH(r, f) ({ \ | |
449 | typeof((f)(NULL)) __PTR_RING_PEEK_CALL_v; \ | |
450 | \ | |
451 | spin_lock_bh(&(r)->consumer_lock); \ | |
452 | __PTR_RING_PEEK_CALL_v = __PTR_RING_PEEK_CALL(r, f); \ | |
453 | spin_unlock_bh(&(r)->consumer_lock); \ | |
454 | __PTR_RING_PEEK_CALL_v; \ | |
455 | }) | |
456 | ||
457 | #define PTR_RING_PEEK_CALL_ANY(r, f) ({ \ | |
458 | typeof((f)(NULL)) __PTR_RING_PEEK_CALL_v; \ | |
459 | unsigned long __PTR_RING_PEEK_CALL_f;\ | |
460 | \ | |
461 | spin_lock_irqsave(&(r)->consumer_lock, __PTR_RING_PEEK_CALL_f); \ | |
462 | __PTR_RING_PEEK_CALL_v = __PTR_RING_PEEK_CALL(r, f); \ | |
463 | spin_unlock_irqrestore(&(r)->consumer_lock, __PTR_RING_PEEK_CALL_f); \ | |
464 | __PTR_RING_PEEK_CALL_v; \ | |
465 | }) | |
466 | ||
0bf7800f JW |
467 | /* Not all gfp_t flags (besides GFP_KERNEL) are allowed. See |
468 | * documentation for vmalloc for which of them are legal. | |
469 | */ | |
81fbfe8a | 470 | static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp) |
5d49de53 | 471 | { |
54e02162 | 472 | if (size > KMALLOC_MAX_SIZE / sizeof(void *)) |
6e6e41c3 | 473 | return NULL; |
0bf7800f | 474 | return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO); |
5d49de53 MT |
475 | } |
476 | ||
fb9de970 MT |
477 | static inline void __ptr_ring_set_size(struct ptr_ring *r, int size) |
478 | { | |
479 | r->size = size; | |
480 | r->batch = SMP_CACHE_BYTES * 2 / sizeof(*(r->queue)); | |
481 | /* We need to set batch at least to 1 to make logic | |
482 | * in __ptr_ring_discard_one work correctly. | |
483 | * Batching too much (because ring is small) would cause a lot of | |
484 | * burstiness. Needs tuning, for now disable batching. | |
485 | */ | |
486 | if (r->batch > r->size / 2 || !r->batch) | |
487 | r->batch = 1; | |
488 | } | |
489 | ||
2e0ab8ca MT |
490 | static inline int ptr_ring_init(struct ptr_ring *r, int size, gfp_t gfp) |
491 | { | |
5d49de53 | 492 | r->queue = __ptr_ring_init_queue_alloc(size, gfp); |
2e0ab8ca MT |
493 | if (!r->queue) |
494 | return -ENOMEM; | |
495 | ||
fb9de970 MT |
496 | __ptr_ring_set_size(r, size); |
497 | r->producer = r->consumer_head = r->consumer_tail = 0; | |
2e0ab8ca MT |
498 | spin_lock_init(&r->producer_lock); |
499 | spin_lock_init(&r->consumer_lock); | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
197a5212 MT |
504 | /* |
505 | * Return entries into ring. Destroy entries that don't fit. | |
506 | * | |
507 | * Note: this is expected to be a rare slow path operation. | |
508 | * | |
509 | * Note: producer lock is nested within consumer lock, so if you | |
510 | * resize you must make sure all uses nest correctly. | |
511 | * In particular if you consume ring in interrupt or BH context, you must | |
512 | * disable interrupts/BH when doing so. | |
513 | */ | |
514 | static inline void ptr_ring_unconsume(struct ptr_ring *r, void **batch, int n, | |
515 | void (*destroy)(void *)) | |
516 | { | |
517 | unsigned long flags; | |
518 | int head; | |
519 | ||
520 | spin_lock_irqsave(&r->consumer_lock, flags); | |
521 | spin_lock(&r->producer_lock); | |
522 | ||
523 | if (!r->size) | |
524 | goto done; | |
525 | ||
526 | /* | |
527 | * Clean out buffered entries (for simplicity). This way following code | |
528 | * can test entries for NULL and if not assume they are valid. | |
529 | */ | |
530 | head = r->consumer_head - 1; | |
531 | while (likely(head >= r->consumer_tail)) | |
532 | r->queue[head--] = NULL; | |
533 | r->consumer_tail = r->consumer_head; | |
534 | ||
535 | /* | |
536 | * Go over entries in batch, start moving head back and copy entries. | |
537 | * Stop when we run into previously unconsumed entries. | |
538 | */ | |
539 | while (n) { | |
540 | head = r->consumer_head - 1; | |
541 | if (head < 0) | |
542 | head = r->size - 1; | |
543 | if (r->queue[head]) { | |
544 | /* This batch entry will have to be destroyed. */ | |
545 | goto done; | |
546 | } | |
547 | r->queue[head] = batch[--n]; | |
a259df36 MT |
548 | r->consumer_tail = head; |
549 | /* matching READ_ONCE in __ptr_ring_empty for lockless tests */ | |
550 | WRITE_ONCE(r->consumer_head, head); | |
197a5212 MT |
551 | } |
552 | ||
553 | done: | |
554 | /* Destroy all entries left in the batch. */ | |
555 | while (n) | |
556 | destroy(batch[--n]); | |
557 | spin_unlock(&r->producer_lock); | |
558 | spin_unlock_irqrestore(&r->consumer_lock, flags); | |
559 | } | |
560 | ||
59e6ae53 MT |
561 | static inline void **__ptr_ring_swap_queue(struct ptr_ring *r, void **queue, |
562 | int size, gfp_t gfp, | |
563 | void (*destroy)(void *)) | |
5d49de53 | 564 | { |
5d49de53 | 565 | int producer = 0; |
5d49de53 MT |
566 | void **old; |
567 | void *ptr; | |
568 | ||
e7169530 | 569 | while ((ptr = __ptr_ring_consume(r))) |
5d49de53 MT |
570 | if (producer < size) |
571 | queue[producer++] = ptr; | |
572 | else if (destroy) | |
573 | destroy(ptr); | |
574 | ||
aff6db45 CW |
575 | if (producer >= size) |
576 | producer = 0; | |
fb9de970 | 577 | __ptr_ring_set_size(r, size); |
5d49de53 | 578 | r->producer = producer; |
fb9de970 MT |
579 | r->consumer_head = 0; |
580 | r->consumer_tail = 0; | |
5d49de53 MT |
581 | old = r->queue; |
582 | r->queue = queue; | |
583 | ||
59e6ae53 MT |
584 | return old; |
585 | } | |
586 | ||
e7169530 MT |
587 | /* |
588 | * Note: producer lock is nested within consumer lock, so if you | |
589 | * resize you must make sure all uses nest correctly. | |
590 | * In particular if you consume ring in interrupt or BH context, you must | |
591 | * disable interrupts/BH when doing so. | |
592 | */ | |
59e6ae53 MT |
593 | static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, |
594 | void (*destroy)(void *)) | |
595 | { | |
596 | unsigned long flags; | |
597 | void **queue = __ptr_ring_init_queue_alloc(size, gfp); | |
598 | void **old; | |
599 | ||
600 | if (!queue) | |
601 | return -ENOMEM; | |
602 | ||
e7169530 MT |
603 | spin_lock_irqsave(&(r)->consumer_lock, flags); |
604 | spin_lock(&(r)->producer_lock); | |
59e6ae53 MT |
605 | |
606 | old = __ptr_ring_swap_queue(r, queue, size, gfp, destroy); | |
607 | ||
e7169530 MT |
608 | spin_unlock(&(r)->producer_lock); |
609 | spin_unlock_irqrestore(&(r)->consumer_lock, flags); | |
5d49de53 | 610 | |
0bf7800f | 611 | kvfree(old); |
5d49de53 MT |
612 | |
613 | return 0; | |
614 | } | |
615 | ||
e7169530 MT |
616 | /* |
617 | * Note: producer lock is nested within consumer lock, so if you | |
618 | * resize you must make sure all uses nest correctly. | |
619 | * In particular if you consume ring in interrupt or BH context, you must | |
620 | * disable interrupts/BH when doing so. | |
621 | */ | |
81fbfe8a ED |
622 | static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, |
623 | unsigned int nrings, | |
59e6ae53 MT |
624 | int size, |
625 | gfp_t gfp, void (*destroy)(void *)) | |
626 | { | |
627 | unsigned long flags; | |
628 | void ***queues; | |
629 | int i; | |
630 | ||
81fbfe8a | 631 | queues = kmalloc_array(nrings, sizeof(*queues), gfp); |
59e6ae53 MT |
632 | if (!queues) |
633 | goto noqueues; | |
634 | ||
635 | for (i = 0; i < nrings; ++i) { | |
636 | queues[i] = __ptr_ring_init_queue_alloc(size, gfp); | |
637 | if (!queues[i]) | |
638 | goto nomem; | |
639 | } | |
640 | ||
641 | for (i = 0; i < nrings; ++i) { | |
e7169530 MT |
642 | spin_lock_irqsave(&(rings[i])->consumer_lock, flags); |
643 | spin_lock(&(rings[i])->producer_lock); | |
59e6ae53 MT |
644 | queues[i] = __ptr_ring_swap_queue(rings[i], queues[i], |
645 | size, gfp, destroy); | |
e7169530 MT |
646 | spin_unlock(&(rings[i])->producer_lock); |
647 | spin_unlock_irqrestore(&(rings[i])->consumer_lock, flags); | |
59e6ae53 MT |
648 | } |
649 | ||
650 | for (i = 0; i < nrings; ++i) | |
0bf7800f | 651 | kvfree(queues[i]); |
59e6ae53 MT |
652 | |
653 | kfree(queues); | |
654 | ||
655 | return 0; | |
656 | ||
657 | nomem: | |
658 | while (--i >= 0) | |
0bf7800f | 659 | kvfree(queues[i]); |
59e6ae53 MT |
660 | |
661 | kfree(queues); | |
662 | ||
663 | noqueues: | |
664 | return -ENOMEM; | |
665 | } | |
666 | ||
5d49de53 | 667 | static inline void ptr_ring_cleanup(struct ptr_ring *r, void (*destroy)(void *)) |
2e0ab8ca | 668 | { |
5d49de53 MT |
669 | void *ptr; |
670 | ||
671 | if (destroy) | |
672 | while ((ptr = ptr_ring_consume(r))) | |
673 | destroy(ptr); | |
0bf7800f | 674 | kvfree(r->queue); |
2e0ab8ca MT |
675 | } |
676 | ||
677 | #endif /* _LINUX_PTR_RING_H */ |