Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * Copyright (C) 2016 Facebook
4 : * Copyright (C) 2013-2014 Jens Axboe
5 : */
6 :
7 : #include <linux/sched.h>
8 : #include <linux/random.h>
9 : #include <linux/sbitmap.h>
10 : #include <linux/seq_file.h>
11 :
12 0 : static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
13 : {
14 0 : unsigned depth = sb->depth;
15 :
16 0 : sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
17 0 : if (!sb->alloc_hint)
18 : return -ENOMEM;
19 :
20 0 : if (depth && !sb->round_robin) {
21 : int i;
22 :
23 0 : for_each_possible_cpu(i)
24 0 : *per_cpu_ptr(sb->alloc_hint, i) = get_random_u32_below(depth);
25 : }
26 : return 0;
27 : }
28 :
29 0 : static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
30 : unsigned int depth)
31 : {
32 : unsigned hint;
33 :
34 0 : hint = this_cpu_read(*sb->alloc_hint);
35 0 : if (unlikely(hint >= depth)) {
36 0 : hint = depth ? get_random_u32_below(depth) : 0;
37 0 : this_cpu_write(*sb->alloc_hint, hint);
38 : }
39 :
40 0 : return hint;
41 : }
42 :
43 0 : static inline void update_alloc_hint_after_get(struct sbitmap *sb,
44 : unsigned int depth,
45 : unsigned int hint,
46 : unsigned int nr)
47 : {
48 0 : if (nr == -1) {
49 : /* If the map is full, a hint won't do us much good. */
50 0 : this_cpu_write(*sb->alloc_hint, 0);
51 0 : } else if (nr == hint || unlikely(sb->round_robin)) {
52 : /* Only update the hint if we used it. */
53 0 : hint = nr + 1;
54 0 : if (hint >= depth - 1)
55 0 : hint = 0;
56 0 : this_cpu_write(*sb->alloc_hint, hint);
57 : }
58 0 : }
59 :
60 : /*
61 : * See if we have deferred clears that we can batch move
62 : */
63 : static inline bool sbitmap_deferred_clear(struct sbitmap_word *map)
64 : {
65 : unsigned long mask;
66 :
67 0 : if (!READ_ONCE(map->cleared))
68 : return false;
69 :
70 : /*
71 : * First get a stable cleared mask, setting the old mask to 0.
72 : */
73 0 : mask = xchg(&map->cleared, 0);
74 :
75 : /*
76 : * Now clear the masked bits in our free word
77 : */
78 0 : atomic_long_andnot(mask, (atomic_long_t *)&map->word);
79 : BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
80 : return true;
81 : }
82 :
83 0 : int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
84 : gfp_t flags, int node, bool round_robin,
85 : bool alloc_hint)
86 : {
87 : unsigned int bits_per_word;
88 :
89 0 : if (shift < 0)
90 : shift = sbitmap_calculate_shift(depth);
91 :
92 0 : bits_per_word = 1U << shift;
93 0 : if (bits_per_word > BITS_PER_LONG)
94 : return -EINVAL;
95 :
96 0 : sb->shift = shift;
97 0 : sb->depth = depth;
98 0 : sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
99 0 : sb->round_robin = round_robin;
100 :
101 0 : if (depth == 0) {
102 0 : sb->map = NULL;
103 0 : return 0;
104 : }
105 :
106 0 : if (alloc_hint) {
107 0 : if (init_alloc_hint(sb, flags))
108 : return -ENOMEM;
109 : } else {
110 0 : sb->alloc_hint = NULL;
111 : }
112 :
113 0 : sb->map = kvzalloc_node(sb->map_nr * sizeof(*sb->map), flags, node);
114 0 : if (!sb->map) {
115 0 : free_percpu(sb->alloc_hint);
116 0 : return -ENOMEM;
117 : }
118 :
119 : return 0;
120 : }
121 : EXPORT_SYMBOL_GPL(sbitmap_init_node);
122 :
123 0 : void sbitmap_resize(struct sbitmap *sb, unsigned int depth)
124 : {
125 0 : unsigned int bits_per_word = 1U << sb->shift;
126 : unsigned int i;
127 :
128 0 : for (i = 0; i < sb->map_nr; i++)
129 0 : sbitmap_deferred_clear(&sb->map[i]);
130 :
131 0 : sb->depth = depth;
132 0 : sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
133 0 : }
134 : EXPORT_SYMBOL_GPL(sbitmap_resize);
135 :
136 0 : static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
137 : unsigned int hint, bool wrap)
138 : {
139 : int nr;
140 :
141 : /* don't wrap if starting from 0 */
142 0 : wrap = wrap && hint;
143 :
144 : while (1) {
145 0 : nr = find_next_zero_bit(word, depth, hint);
146 0 : if (unlikely(nr >= depth)) {
147 : /*
148 : * We started with an offset, and we didn't reset the
149 : * offset to 0 in a failure case, so start from 0 to
150 : * exhaust the map.
151 : */
152 0 : if (hint && wrap) {
153 0 : hint = 0;
154 0 : continue;
155 : }
156 : return -1;
157 : }
158 :
159 0 : if (!test_and_set_bit_lock(nr, word))
160 : break;
161 :
162 0 : hint = nr + 1;
163 0 : if (hint >= depth - 1)
164 0 : hint = 0;
165 : }
166 :
167 : return nr;
168 : }
169 :
170 0 : static int sbitmap_find_bit_in_word(struct sbitmap_word *map,
171 : unsigned int depth,
172 : unsigned int alloc_hint,
173 : bool wrap)
174 : {
175 : int nr;
176 :
177 : do {
178 0 : nr = __sbitmap_get_word(&map->word, depth,
179 : alloc_hint, wrap);
180 0 : if (nr != -1)
181 : break;
182 0 : if (!sbitmap_deferred_clear(map))
183 : break;
184 : } while (1);
185 :
186 0 : return nr;
187 : }
188 :
189 0 : static int sbitmap_find_bit(struct sbitmap *sb,
190 : unsigned int depth,
191 : unsigned int index,
192 : unsigned int alloc_hint,
193 : bool wrap)
194 : {
195 : unsigned int i;
196 0 : int nr = -1;
197 :
198 0 : for (i = 0; i < sb->map_nr; i++) {
199 0 : nr = sbitmap_find_bit_in_word(&sb->map[index],
200 0 : min_t(unsigned int,
201 : __map_depth(sb, index),
202 : depth),
203 : alloc_hint, wrap);
204 :
205 0 : if (nr != -1) {
206 0 : nr += index << sb->shift;
207 0 : break;
208 : }
209 :
210 : /* Jump to next index. */
211 0 : alloc_hint = 0;
212 0 : if (++index >= sb->map_nr)
213 0 : index = 0;
214 : }
215 :
216 0 : return nr;
217 : }
218 :
219 0 : static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
220 : {
221 : unsigned int index;
222 :
223 0 : index = SB_NR_TO_INDEX(sb, alloc_hint);
224 :
225 : /*
226 : * Unless we're doing round robin tag allocation, just use the
227 : * alloc_hint to find the right word index. No point in looping
228 : * twice in find_next_zero_bit() for that case.
229 : */
230 0 : if (sb->round_robin)
231 0 : alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
232 : else
233 : alloc_hint = 0;
234 :
235 0 : return sbitmap_find_bit(sb, UINT_MAX, index, alloc_hint,
236 0 : !sb->round_robin);
237 : }
238 :
239 0 : int sbitmap_get(struct sbitmap *sb)
240 : {
241 : int nr;
242 : unsigned int hint, depth;
243 :
244 0 : if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
245 : return -1;
246 :
247 0 : depth = READ_ONCE(sb->depth);
248 0 : hint = update_alloc_hint_before_get(sb, depth);
249 0 : nr = __sbitmap_get(sb, hint);
250 0 : update_alloc_hint_after_get(sb, depth, hint, nr);
251 :
252 0 : return nr;
253 : }
254 : EXPORT_SYMBOL_GPL(sbitmap_get);
255 :
256 : static int __sbitmap_get_shallow(struct sbitmap *sb,
257 : unsigned int alloc_hint,
258 : unsigned long shallow_depth)
259 : {
260 : unsigned int index;
261 :
262 0 : index = SB_NR_TO_INDEX(sb, alloc_hint);
263 0 : alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
264 :
265 0 : return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true);
266 : }
267 :
268 0 : int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
269 : {
270 : int nr;
271 : unsigned int hint, depth;
272 :
273 0 : if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
274 : return -1;
275 :
276 0 : depth = READ_ONCE(sb->depth);
277 0 : hint = update_alloc_hint_before_get(sb, depth);
278 0 : nr = __sbitmap_get_shallow(sb, hint, shallow_depth);
279 0 : update_alloc_hint_after_get(sb, depth, hint, nr);
280 :
281 0 : return nr;
282 : }
283 : EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
284 :
285 0 : bool sbitmap_any_bit_set(const struct sbitmap *sb)
286 : {
287 : unsigned int i;
288 :
289 0 : for (i = 0; i < sb->map_nr; i++) {
290 0 : if (sb->map[i].word & ~sb->map[i].cleared)
291 : return true;
292 : }
293 : return false;
294 : }
295 : EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
296 :
297 0 : static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
298 : {
299 0 : unsigned int i, weight = 0;
300 :
301 0 : for (i = 0; i < sb->map_nr; i++) {
302 0 : const struct sbitmap_word *word = &sb->map[i];
303 0 : unsigned int word_depth = __map_depth(sb, i);
304 :
305 0 : if (set)
306 0 : weight += bitmap_weight(&word->word, word_depth);
307 : else
308 0 : weight += bitmap_weight(&word->cleared, word_depth);
309 : }
310 0 : return weight;
311 : }
312 :
313 : static unsigned int sbitmap_cleared(const struct sbitmap *sb)
314 : {
315 0 : return __sbitmap_weight(sb, false);
316 : }
317 :
318 0 : unsigned int sbitmap_weight(const struct sbitmap *sb)
319 : {
320 0 : return __sbitmap_weight(sb, true) - sbitmap_cleared(sb);
321 : }
322 : EXPORT_SYMBOL_GPL(sbitmap_weight);
323 :
324 0 : void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
325 : {
326 0 : seq_printf(m, "depth=%u\n", sb->depth);
327 0 : seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
328 0 : seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
329 0 : seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
330 0 : seq_printf(m, "map_nr=%u\n", sb->map_nr);
331 0 : }
332 : EXPORT_SYMBOL_GPL(sbitmap_show);
333 :
334 0 : static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
335 : {
336 0 : if ((offset & 0xf) == 0) {
337 0 : if (offset != 0)
338 0 : seq_putc(m, '\n');
339 0 : seq_printf(m, "%08x:", offset);
340 : }
341 0 : if ((offset & 0x1) == 0)
342 0 : seq_putc(m, ' ');
343 0 : seq_printf(m, "%02x", byte);
344 0 : }
345 :
346 0 : void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
347 : {
348 0 : u8 byte = 0;
349 0 : unsigned int byte_bits = 0;
350 0 : unsigned int offset = 0;
351 : int i;
352 :
353 0 : for (i = 0; i < sb->map_nr; i++) {
354 0 : unsigned long word = READ_ONCE(sb->map[i].word);
355 0 : unsigned long cleared = READ_ONCE(sb->map[i].cleared);
356 0 : unsigned int word_bits = __map_depth(sb, i);
357 :
358 0 : word &= ~cleared;
359 :
360 0 : while (word_bits > 0) {
361 0 : unsigned int bits = min(8 - byte_bits, word_bits);
362 :
363 0 : byte |= (word & (BIT(bits) - 1)) << byte_bits;
364 0 : byte_bits += bits;
365 0 : if (byte_bits == 8) {
366 0 : emit_byte(m, offset, byte);
367 0 : byte = 0;
368 0 : byte_bits = 0;
369 0 : offset++;
370 : }
371 0 : word >>= bits;
372 0 : word_bits -= bits;
373 : }
374 : }
375 0 : if (byte_bits) {
376 0 : emit_byte(m, offset, byte);
377 0 : offset++;
378 : }
379 0 : if (offset)
380 0 : seq_putc(m, '\n');
381 0 : }
382 : EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
383 :
384 : static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
385 : unsigned int depth)
386 : {
387 : unsigned int wake_batch;
388 : unsigned int shallow_depth;
389 :
390 : /*
391 : * For each batch, we wake up one queue. We need to make sure that our
392 : * batch size is small enough that the full depth of the bitmap,
393 : * potentially limited by a shallow depth, is enough to wake up all of
394 : * the queues.
395 : *
396 : * Each full word of the bitmap has bits_per_word bits, and there might
397 : * be a partial word. There are depth / bits_per_word full words and
398 : * depth % bits_per_word bits left over. In bitwise arithmetic:
399 : *
400 : * bits_per_word = 1 << shift
401 : * depth / bits_per_word = depth >> shift
402 : * depth % bits_per_word = depth & ((1 << shift) - 1)
403 : *
404 : * Each word can be limited to sbq->min_shallow_depth bits.
405 : */
406 0 : shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth);
407 0 : depth = ((depth >> sbq->sb.shift) * shallow_depth +
408 0 : min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth));
409 0 : wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1,
410 : SBQ_WAKE_BATCH);
411 :
412 : return wake_batch;
413 : }
414 :
415 0 : int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
416 : int shift, bool round_robin, gfp_t flags, int node)
417 : {
418 : int ret;
419 : int i;
420 :
421 0 : ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
422 : round_robin, true);
423 0 : if (ret)
424 : return ret;
425 :
426 0 : sbq->min_shallow_depth = UINT_MAX;
427 0 : sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
428 0 : atomic_set(&sbq->wake_index, 0);
429 0 : atomic_set(&sbq->ws_active, 0);
430 0 : atomic_set(&sbq->completion_cnt, 0);
431 0 : atomic_set(&sbq->wakeup_cnt, 0);
432 :
433 0 : sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
434 0 : if (!sbq->ws) {
435 0 : sbitmap_free(&sbq->sb);
436 0 : return -ENOMEM;
437 : }
438 :
439 0 : for (i = 0; i < SBQ_WAIT_QUEUES; i++)
440 0 : init_waitqueue_head(&sbq->ws[i].wait);
441 :
442 : return 0;
443 : }
444 : EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
445 :
446 : static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
447 : unsigned int depth)
448 : {
449 : unsigned int wake_batch;
450 :
451 0 : wake_batch = sbq_calc_wake_batch(sbq, depth);
452 0 : if (sbq->wake_batch != wake_batch)
453 0 : WRITE_ONCE(sbq->wake_batch, wake_batch);
454 : }
455 :
456 0 : void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
457 : unsigned int users)
458 : {
459 : unsigned int wake_batch;
460 0 : unsigned int depth = (sbq->sb.depth + users - 1) / users;
461 :
462 0 : wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
463 : 1, SBQ_WAKE_BATCH);
464 :
465 0 : WRITE_ONCE(sbq->wake_batch, wake_batch);
466 0 : }
467 : EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
468 :
469 0 : void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
470 : {
471 0 : sbitmap_queue_update_wake_batch(sbq, depth);
472 0 : sbitmap_resize(&sbq->sb, depth);
473 0 : }
474 : EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
475 :
476 0 : int __sbitmap_queue_get(struct sbitmap_queue *sbq)
477 : {
478 0 : return sbitmap_get(&sbq->sb);
479 : }
480 : EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
481 :
482 0 : unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
483 : unsigned int *offset)
484 : {
485 0 : struct sbitmap *sb = &sbq->sb;
486 : unsigned int hint, depth;
487 : unsigned long index, nr;
488 : int i;
489 :
490 0 : if (unlikely(sb->round_robin))
491 : return 0;
492 :
493 0 : depth = READ_ONCE(sb->depth);
494 0 : hint = update_alloc_hint_before_get(sb, depth);
495 :
496 0 : index = SB_NR_TO_INDEX(sb, hint);
497 :
498 0 : for (i = 0; i < sb->map_nr; i++) {
499 0 : struct sbitmap_word *map = &sb->map[index];
500 : unsigned long get_mask;
501 0 : unsigned int map_depth = __map_depth(sb, index);
502 :
503 0 : sbitmap_deferred_clear(map);
504 0 : if (map->word == (1UL << (map_depth - 1)) - 1)
505 : goto next;
506 :
507 0 : nr = find_first_zero_bit(&map->word, map_depth);
508 0 : if (nr + nr_tags <= map_depth) {
509 0 : atomic_long_t *ptr = (atomic_long_t *) &map->word;
510 : unsigned long val;
511 :
512 0 : get_mask = ((1UL << nr_tags) - 1) << nr;
513 0 : val = READ_ONCE(map->word);
514 0 : while (!atomic_long_try_cmpxchg(ptr, &val,
515 0 : get_mask | val))
516 : ;
517 0 : get_mask = (get_mask & ~val) >> nr;
518 0 : if (get_mask) {
519 0 : *offset = nr + (index << sb->shift);
520 0 : update_alloc_hint_after_get(sb, depth, hint,
521 0 : *offset + nr_tags - 1);
522 0 : return get_mask;
523 : }
524 : }
525 : next:
526 : /* Jump to next index. */
527 0 : if (++index >= sb->map_nr)
528 0 : index = 0;
529 : }
530 :
531 : return 0;
532 : }
533 :
534 0 : int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
535 : unsigned int shallow_depth)
536 : {
537 0 : WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
538 :
539 0 : return sbitmap_get_shallow(&sbq->sb, shallow_depth);
540 : }
541 : EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow);
542 :
543 0 : void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
544 : unsigned int min_shallow_depth)
545 : {
546 0 : sbq->min_shallow_depth = min_shallow_depth;
547 0 : sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth);
548 0 : }
549 : EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
550 :
551 0 : static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
552 : {
553 : int i, wake_index;
554 :
555 0 : if (!atomic_read(&sbq->ws_active))
556 : return;
557 :
558 0 : wake_index = atomic_read(&sbq->wake_index);
559 0 : for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
560 0 : struct sbq_wait_state *ws = &sbq->ws[wake_index];
561 :
562 : /*
563 : * Advance the index before checking the current queue.
564 : * It improves fairness, by ensuring the queue doesn't
565 : * need to be fully emptied before trying to wake up
566 : * from the next one.
567 : */
568 0 : wake_index = sbq_index_inc(wake_index);
569 :
570 : /*
571 : * It is sufficient to wake up at least one waiter to
572 : * guarantee forward progress.
573 : */
574 0 : if (waitqueue_active(&ws->wait) &&
575 0 : wake_up_nr(&ws->wait, nr))
576 : break;
577 : }
578 :
579 0 : if (wake_index != atomic_read(&sbq->wake_index))
580 0 : atomic_set(&sbq->wake_index, wake_index);
581 : }
582 :
583 0 : void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
584 : {
585 0 : unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
586 : unsigned int wakeups;
587 :
588 0 : if (!atomic_read(&sbq->ws_active))
589 : return;
590 :
591 0 : atomic_add(nr, &sbq->completion_cnt);
592 0 : wakeups = atomic_read(&sbq->wakeup_cnt);
593 :
594 : do {
595 0 : if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch)
596 : return;
597 0 : } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt,
598 0 : &wakeups, wakeups + wake_batch));
599 :
600 0 : __sbitmap_queue_wake_up(sbq, wake_batch);
601 : }
602 : EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
603 :
604 : static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
605 : {
606 0 : if (likely(!sb->round_robin && tag < sb->depth))
607 0 : data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
608 : }
609 :
610 0 : void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
611 : int *tags, int nr_tags)
612 : {
613 0 : struct sbitmap *sb = &sbq->sb;
614 0 : unsigned long *addr = NULL;
615 0 : unsigned long mask = 0;
616 : int i;
617 :
618 0 : smp_mb__before_atomic();
619 0 : for (i = 0; i < nr_tags; i++) {
620 0 : const int tag = tags[i] - offset;
621 : unsigned long *this_addr;
622 :
623 : /* since we're clearing a batch, skip the deferred map */
624 0 : this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
625 0 : if (!addr) {
626 : addr = this_addr;
627 0 : } else if (addr != this_addr) {
628 0 : atomic_long_andnot(mask, (atomic_long_t *) addr);
629 0 : mask = 0;
630 0 : addr = this_addr;
631 : }
632 0 : mask |= (1UL << SB_NR_TO_BIT(sb, tag));
633 : }
634 :
635 0 : if (mask)
636 0 : atomic_long_andnot(mask, (atomic_long_t *) addr);
637 :
638 0 : smp_mb__after_atomic();
639 0 : sbitmap_queue_wake_up(sbq, nr_tags);
640 0 : sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
641 0 : tags[nr_tags - 1] - offset);
642 0 : }
643 :
644 0 : void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
645 : unsigned int cpu)
646 : {
647 : /*
648 : * Once the clear bit is set, the bit may be allocated out.
649 : *
650 : * Orders READ/WRITE on the associated instance(such as request
651 : * of blk_mq) by this bit for avoiding race with re-allocation,
652 : * and its pair is the memory barrier implied in __sbitmap_get_word.
653 : *
654 : * One invariant is that the clear bit has to be zero when the bit
655 : * is in use.
656 : */
657 0 : smp_mb__before_atomic();
658 0 : sbitmap_deferred_clear_bit(&sbq->sb, nr);
659 :
660 : /*
661 : * Pairs with the memory barrier in set_current_state() to ensure the
662 : * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
663 : * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
664 : * waiter. See the comment on waitqueue_active().
665 : */
666 0 : smp_mb__after_atomic();
667 0 : sbitmap_queue_wake_up(sbq, 1);
668 0 : sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
669 0 : }
670 : EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
671 :
672 0 : void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
673 : {
674 : int i, wake_index;
675 :
676 : /*
677 : * Pairs with the memory barrier in set_current_state() like in
678 : * sbitmap_queue_wake_up().
679 : */
680 0 : smp_mb();
681 0 : wake_index = atomic_read(&sbq->wake_index);
682 0 : for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
683 0 : struct sbq_wait_state *ws = &sbq->ws[wake_index];
684 :
685 0 : if (waitqueue_active(&ws->wait))
686 0 : wake_up(&ws->wait);
687 :
688 0 : wake_index = sbq_index_inc(wake_index);
689 : }
690 0 : }
691 : EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
692 :
693 0 : void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
694 : {
695 : bool first;
696 : int i;
697 :
698 0 : sbitmap_show(&sbq->sb, m);
699 :
700 0 : seq_puts(m, "alloc_hint={");
701 0 : first = true;
702 0 : for_each_possible_cpu(i) {
703 0 : if (!first)
704 0 : seq_puts(m, ", ");
705 0 : first = false;
706 0 : seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
707 : }
708 0 : seq_puts(m, "}\n");
709 :
710 0 : seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
711 0 : seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
712 0 : seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
713 :
714 0 : seq_puts(m, "ws={\n");
715 0 : for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
716 0 : struct sbq_wait_state *ws = &sbq->ws[i];
717 0 : seq_printf(m, "\t{.wait=%s},\n",
718 0 : waitqueue_active(&ws->wait) ? "active" : "inactive");
719 : }
720 0 : seq_puts(m, "}\n");
721 :
722 0 : seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
723 0 : seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
724 0 : }
725 : EXPORT_SYMBOL_GPL(sbitmap_queue_show);
726 :
727 0 : void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
728 : struct sbq_wait_state *ws,
729 : struct sbq_wait *sbq_wait)
730 : {
731 0 : if (!sbq_wait->sbq) {
732 0 : sbq_wait->sbq = sbq;
733 0 : atomic_inc(&sbq->ws_active);
734 0 : add_wait_queue(&ws->wait, &sbq_wait->wait);
735 : }
736 0 : }
737 : EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
738 :
739 0 : void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
740 : {
741 0 : list_del_init(&sbq_wait->wait.entry);
742 0 : if (sbq_wait->sbq) {
743 0 : atomic_dec(&sbq_wait->sbq->ws_active);
744 0 : sbq_wait->sbq = NULL;
745 : }
746 0 : }
747 : EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
748 :
749 0 : void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
750 : struct sbq_wait_state *ws,
751 : struct sbq_wait *sbq_wait, int state)
752 : {
753 0 : if (!sbq_wait->sbq) {
754 0 : atomic_inc(&sbq->ws_active);
755 0 : sbq_wait->sbq = sbq;
756 : }
757 0 : prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
758 0 : }
759 : EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
760 :
761 0 : void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
762 : struct sbq_wait *sbq_wait)
763 : {
764 0 : finish_wait(&ws->wait, &sbq_wait->wait);
765 0 : if (sbq_wait->sbq) {
766 0 : atomic_dec(&sbq->ws_active);
767 0 : sbq_wait->sbq = NULL;
768 : }
769 0 : }
770 : EXPORT_SYMBOL_GPL(sbitmap_finish_wait);
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