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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> | |
29 | #include <linux/cache.h> | |
30 | #include <linux/slab.h> | |
31 | #include <asm/errno.h> | |
32 | #endif | |
33 | ||
34 | struct ptr_ring { | |
35 | int producer ____cacheline_aligned_in_smp; | |
36 | spinlock_t producer_lock; | |
fb9de970 MT |
37 | int consumer_head ____cacheline_aligned_in_smp; /* next valid entry */ |
38 | int consumer_tail; /* next entry to invalidate */ | |
2e0ab8ca MT |
39 | spinlock_t consumer_lock; |
40 | /* Shared consumer/producer data */ | |
41 | /* Read-only by both the producer and the consumer */ | |
42 | int size ____cacheline_aligned_in_smp; /* max entries in queue */ | |
fb9de970 | 43 | int batch; /* number of entries to consume in a batch */ |
2e0ab8ca MT |
44 | void **queue; |
45 | }; | |
46 | ||
47 | /* Note: callers invoking this in a loop must use a compiler barrier, | |
84328342 MT |
48 | * for example cpu_relax(). |
49 | * | |
50 | * NB: this is unlike __ptr_ring_empty in that callers must hold producer_lock: | |
51 | * see e.g. ptr_ring_full. | |
2e0ab8ca MT |
52 | */ |
53 | static inline bool __ptr_ring_full(struct ptr_ring *r) | |
54 | { | |
55 | return r->queue[r->producer]; | |
56 | } | |
57 | ||
58 | static inline bool ptr_ring_full(struct ptr_ring *r) | |
59 | { | |
5d49de53 MT |
60 | bool ret; |
61 | ||
62 | spin_lock(&r->producer_lock); | |
63 | ret = __ptr_ring_full(r); | |
64 | spin_unlock(&r->producer_lock); | |
65 | ||
66 | return ret; | |
67 | } | |
68 | ||
69 | static inline bool ptr_ring_full_irq(struct ptr_ring *r) | |
70 | { | |
71 | bool ret; | |
72 | ||
73 | spin_lock_irq(&r->producer_lock); | |
74 | ret = __ptr_ring_full(r); | |
75 | spin_unlock_irq(&r->producer_lock); | |
76 | ||
77 | return ret; | |
78 | } | |
79 | ||
80 | static inline bool ptr_ring_full_any(struct ptr_ring *r) | |
81 | { | |
82 | unsigned long flags; | |
83 | bool ret; | |
84 | ||
85 | spin_lock_irqsave(&r->producer_lock, flags); | |
86 | ret = __ptr_ring_full(r); | |
87 | spin_unlock_irqrestore(&r->producer_lock, flags); | |
88 | ||
89 | return ret; | |
90 | } | |
91 | ||
92 | static inline bool ptr_ring_full_bh(struct ptr_ring *r) | |
93 | { | |
94 | bool ret; | |
95 | ||
96 | spin_lock_bh(&r->producer_lock); | |
97 | ret = __ptr_ring_full(r); | |
98 | spin_unlock_bh(&r->producer_lock); | |
99 | ||
100 | return ret; | |
2e0ab8ca MT |
101 | } |
102 | ||
103 | /* Note: callers invoking this in a loop must use a compiler barrier, | |
5d49de53 | 104 | * for example cpu_relax(). Callers must hold producer_lock. |
a8ceb5db MT |
105 | * Callers are responsible for making sure pointer that is being queued |
106 | * points to a valid data. | |
2e0ab8ca MT |
107 | */ |
108 | static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr) | |
109 | { | |
982fb490 | 110 | if (unlikely(!r->size) || r->queue[r->producer]) |
2e0ab8ca MT |
111 | return -ENOSPC; |
112 | ||
a8ceb5db MT |
113 | /* Make sure the pointer we are storing points to a valid data. */ |
114 | /* Pairs with smp_read_barrier_depends in __ptr_ring_consume. */ | |
115 | smp_wmb(); | |
116 | ||
a07d29c6 | 117 | WRITE_ONCE(r->queue[r->producer++], ptr); |
2e0ab8ca MT |
118 | if (unlikely(r->producer >= r->size)) |
119 | r->producer = 0; | |
120 | return 0; | |
121 | } | |
122 | ||
e7169530 MT |
123 | /* |
124 | * Note: resize (below) nests producer lock within consumer lock, so if you | |
125 | * consume in interrupt or BH context, you must disable interrupts/BH when | |
126 | * calling this. | |
127 | */ | |
2e0ab8ca MT |
128 | static inline int ptr_ring_produce(struct ptr_ring *r, void *ptr) |
129 | { | |
130 | int ret; | |
131 | ||
132 | spin_lock(&r->producer_lock); | |
133 | ret = __ptr_ring_produce(r, ptr); | |
134 | spin_unlock(&r->producer_lock); | |
135 | ||
136 | return ret; | |
137 | } | |
138 | ||
139 | static inline int ptr_ring_produce_irq(struct ptr_ring *r, void *ptr) | |
140 | { | |
141 | int ret; | |
142 | ||
143 | spin_lock_irq(&r->producer_lock); | |
144 | ret = __ptr_ring_produce(r, ptr); | |
145 | spin_unlock_irq(&r->producer_lock); | |
146 | ||
147 | return ret; | |
148 | } | |
149 | ||
150 | static inline int ptr_ring_produce_any(struct ptr_ring *r, void *ptr) | |
151 | { | |
152 | unsigned long flags; | |
153 | int ret; | |
154 | ||
155 | spin_lock_irqsave(&r->producer_lock, flags); | |
156 | ret = __ptr_ring_produce(r, ptr); | |
157 | spin_unlock_irqrestore(&r->producer_lock, flags); | |
158 | ||
159 | return ret; | |
160 | } | |
161 | ||
162 | static inline int ptr_ring_produce_bh(struct ptr_ring *r, void *ptr) | |
163 | { | |
164 | int ret; | |
165 | ||
166 | spin_lock_bh(&r->producer_lock); | |
167 | ret = __ptr_ring_produce(r, ptr); | |
168 | spin_unlock_bh(&r->producer_lock); | |
169 | ||
170 | return ret; | |
171 | } | |
172 | ||
2e0ab8ca MT |
173 | static inline void *__ptr_ring_peek(struct ptr_ring *r) |
174 | { | |
982fb490 | 175 | if (likely(r->size)) |
a07d29c6 | 176 | return READ_ONCE(r->queue[r->consumer_head]); |
982fb490 | 177 | return NULL; |
2e0ab8ca MT |
178 | } |
179 | ||
8619d384 MT |
180 | /* |
181 | * Test ring empty status without taking any locks. | |
182 | * | |
183 | * NB: This is only safe to call if ring is never resized. | |
184 | * | |
185 | * However, if some other CPU consumes ring entries at the same time, the value | |
186 | * returned is not guaranteed to be correct. | |
187 | * | |
188 | * In this case - to avoid incorrectly detecting the ring | |
189 | * as empty - the CPU consuming the ring entries is responsible | |
190 | * for either consuming all ring entries until the ring is empty, | |
191 | * or synchronizing with some other CPU and causing it to | |
192 | * re-test __ptr_ring_empty and/or consume the ring enteries | |
193 | * after the synchronization point. | |
194 | * | |
195 | * Note: callers invoking this in a loop must use a compiler barrier, | |
196 | * for example cpu_relax(). | |
197 | */ | |
5d49de53 | 198 | static inline bool __ptr_ring_empty(struct ptr_ring *r) |
2e0ab8ca | 199 | { |
a259df36 MT |
200 | if (likely(r->size)) |
201 | return !r->queue[READ_ONCE(r->consumer_head)]; | |
202 | return true; | |
2e0ab8ca MT |
203 | } |
204 | ||
5d49de53 MT |
205 | static inline bool ptr_ring_empty(struct ptr_ring *r) |
206 | { | |
207 | bool ret; | |
208 | ||
209 | spin_lock(&r->consumer_lock); | |
210 | ret = __ptr_ring_empty(r); | |
211 | spin_unlock(&r->consumer_lock); | |
212 | ||
213 | return ret; | |
214 | } | |
215 | ||
216 | static inline bool ptr_ring_empty_irq(struct ptr_ring *r) | |
217 | { | |
218 | bool ret; | |
219 | ||
220 | spin_lock_irq(&r->consumer_lock); | |
221 | ret = __ptr_ring_empty(r); | |
222 | spin_unlock_irq(&r->consumer_lock); | |
223 | ||
224 | return ret; | |
225 | } | |
226 | ||
227 | static inline bool ptr_ring_empty_any(struct ptr_ring *r) | |
228 | { | |
229 | unsigned long flags; | |
230 | bool ret; | |
231 | ||
232 | spin_lock_irqsave(&r->consumer_lock, flags); | |
233 | ret = __ptr_ring_empty(r); | |
234 | spin_unlock_irqrestore(&r->consumer_lock, flags); | |
235 | ||
236 | return ret; | |
237 | } | |
238 | ||
239 | static inline bool ptr_ring_empty_bh(struct ptr_ring *r) | |
240 | { | |
241 | bool ret; | |
242 | ||
243 | spin_lock_bh(&r->consumer_lock); | |
244 | ret = __ptr_ring_empty(r); | |
245 | spin_unlock_bh(&r->consumer_lock); | |
246 | ||
247 | return ret; | |
248 | } | |
249 | ||
2e0ab8ca MT |
250 | /* Must only be called after __ptr_ring_peek returned !NULL */ |
251 | static inline void __ptr_ring_discard_one(struct ptr_ring *r) | |
252 | { | |
fb9de970 MT |
253 | /* Fundamentally, what we want to do is update consumer |
254 | * index and zero out the entry so producer can reuse it. | |
255 | * Doing it naively at each consume would be as simple as: | |
406de755 MT |
256 | * consumer = r->consumer; |
257 | * r->queue[consumer++] = NULL; | |
258 | * if (unlikely(consumer >= r->size)) | |
259 | * consumer = 0; | |
260 | * r->consumer = consumer; | |
fb9de970 MT |
261 | * but that is suboptimal when the ring is full as producer is writing |
262 | * out new entries in the same cache line. Defer these updates until a | |
263 | * batch of entries has been consumed. | |
264 | */ | |
406de755 MT |
265 | /* Note: we must keep consumer_head valid at all times for __ptr_ring_empty |
266 | * to work correctly. | |
267 | */ | |
268 | int consumer_head = r->consumer_head; | |
269 | int head = consumer_head++; | |
fb9de970 MT |
270 | |
271 | /* Once we have processed enough entries invalidate them in | |
272 | * the ring all at once so producer can reuse their space in the ring. | |
273 | * We also do this when we reach end of the ring - not mandatory | |
274 | * but helps keep the implementation simple. | |
275 | */ | |
406de755 MT |
276 | if (unlikely(consumer_head - r->consumer_tail >= r->batch || |
277 | consumer_head >= r->size)) { | |
fb9de970 MT |
278 | /* Zero out entries in the reverse order: this way we touch the |
279 | * cache line that producer might currently be reading the last; | |
280 | * producer won't make progress and touch other cache lines | |
281 | * besides the first one until we write out all entries. | |
282 | */ | |
283 | while (likely(head >= r->consumer_tail)) | |
284 | r->queue[head--] = NULL; | |
406de755 | 285 | r->consumer_tail = consumer_head; |
fb9de970 | 286 | } |
406de755 MT |
287 | if (unlikely(consumer_head >= r->size)) { |
288 | consumer_head = 0; | |
fb9de970 MT |
289 | r->consumer_tail = 0; |
290 | } | |
a259df36 MT |
291 | /* matching READ_ONCE in __ptr_ring_empty for lockless tests */ |
292 | WRITE_ONCE(r->consumer_head, consumer_head); | |
2e0ab8ca MT |
293 | } |
294 | ||
295 | static inline void *__ptr_ring_consume(struct ptr_ring *r) | |
296 | { | |
297 | void *ptr; | |
298 | ||
299 | ptr = __ptr_ring_peek(r); | |
300 | if (ptr) | |
301 | __ptr_ring_discard_one(r); | |
302 | ||
a8ceb5db MT |
303 | /* Make sure anyone accessing data through the pointer is up to date. */ |
304 | /* Pairs with smp_wmb in __ptr_ring_produce. */ | |
305 | smp_read_barrier_depends(); | |
2e0ab8ca MT |
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 | { |
6e6e41c3 JW |
472 | if (size * sizeof(void *) > KMALLOC_MAX_SIZE) |
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 | ||
fb9de970 | 575 | __ptr_ring_set_size(r, size); |
5d49de53 | 576 | r->producer = producer; |
fb9de970 MT |
577 | r->consumer_head = 0; |
578 | r->consumer_tail = 0; | |
5d49de53 MT |
579 | old = r->queue; |
580 | r->queue = queue; | |
581 | ||
59e6ae53 MT |
582 | return old; |
583 | } | |
584 | ||
e7169530 MT |
585 | /* |
586 | * Note: producer lock is nested within consumer lock, so if you | |
587 | * resize you must make sure all uses nest correctly. | |
588 | * In particular if you consume ring in interrupt or BH context, you must | |
589 | * disable interrupts/BH when doing so. | |
590 | */ | |
59e6ae53 MT |
591 | static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, |
592 | void (*destroy)(void *)) | |
593 | { | |
594 | unsigned long flags; | |
595 | void **queue = __ptr_ring_init_queue_alloc(size, gfp); | |
596 | void **old; | |
597 | ||
598 | if (!queue) | |
599 | return -ENOMEM; | |
600 | ||
e7169530 MT |
601 | spin_lock_irqsave(&(r)->consumer_lock, flags); |
602 | spin_lock(&(r)->producer_lock); | |
59e6ae53 MT |
603 | |
604 | old = __ptr_ring_swap_queue(r, queue, size, gfp, destroy); | |
605 | ||
e7169530 MT |
606 | spin_unlock(&(r)->producer_lock); |
607 | spin_unlock_irqrestore(&(r)->consumer_lock, flags); | |
5d49de53 | 608 | |
0bf7800f | 609 | kvfree(old); |
5d49de53 MT |
610 | |
611 | return 0; | |
612 | } | |
613 | ||
e7169530 MT |
614 | /* |
615 | * Note: producer lock is nested within consumer lock, so if you | |
616 | * resize you must make sure all uses nest correctly. | |
617 | * In particular if you consume ring in interrupt or BH context, you must | |
618 | * disable interrupts/BH when doing so. | |
619 | */ | |
81fbfe8a ED |
620 | static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, |
621 | unsigned int nrings, | |
59e6ae53 MT |
622 | int size, |
623 | gfp_t gfp, void (*destroy)(void *)) | |
624 | { | |
625 | unsigned long flags; | |
626 | void ***queues; | |
627 | int i; | |
628 | ||
81fbfe8a | 629 | queues = kmalloc_array(nrings, sizeof(*queues), gfp); |
59e6ae53 MT |
630 | if (!queues) |
631 | goto noqueues; | |
632 | ||
633 | for (i = 0; i < nrings; ++i) { | |
634 | queues[i] = __ptr_ring_init_queue_alloc(size, gfp); | |
635 | if (!queues[i]) | |
636 | goto nomem; | |
637 | } | |
638 | ||
639 | for (i = 0; i < nrings; ++i) { | |
e7169530 MT |
640 | spin_lock_irqsave(&(rings[i])->consumer_lock, flags); |
641 | spin_lock(&(rings[i])->producer_lock); | |
59e6ae53 MT |
642 | queues[i] = __ptr_ring_swap_queue(rings[i], queues[i], |
643 | size, gfp, destroy); | |
e7169530 MT |
644 | spin_unlock(&(rings[i])->producer_lock); |
645 | spin_unlock_irqrestore(&(rings[i])->consumer_lock, flags); | |
59e6ae53 MT |
646 | } |
647 | ||
648 | for (i = 0; i < nrings; ++i) | |
0bf7800f | 649 | kvfree(queues[i]); |
59e6ae53 MT |
650 | |
651 | kfree(queues); | |
652 | ||
653 | return 0; | |
654 | ||
655 | nomem: | |
656 | while (--i >= 0) | |
0bf7800f | 657 | kvfree(queues[i]); |
59e6ae53 MT |
658 | |
659 | kfree(queues); | |
660 | ||
661 | noqueues: | |
662 | return -ENOMEM; | |
663 | } | |
664 | ||
5d49de53 | 665 | static inline void ptr_ring_cleanup(struct ptr_ring *r, void (*destroy)(void *)) |
2e0ab8ca | 666 | { |
5d49de53 MT |
667 | void *ptr; |
668 | ||
669 | if (destroy) | |
670 | while ((ptr = ptr_ring_consume(r))) | |
671 | destroy(ptr); | |
0bf7800f | 672 | kvfree(r->queue); |
2e0ab8ca MT |
673 | } |
674 | ||
675 | #endif /* _LINUX_PTR_RING_H */ |