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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
12static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
13{
14 unsigned depth = sb->depth;
15
16 sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
17 if (!sb->alloc_hint)
18 return -ENOMEM;
19
20 if (depth && !sb->round_robin) {
21 int i;
22
23 for_each_possible_cpu(i)
24 *per_cpu_ptr(sb->alloc_hint, i) = get_random_u32_below(ceil: depth);
25 }
26 return 0;
27}
28
29static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
30 unsigned int depth)
31{
32 unsigned hint;
33
34 hint = this_cpu_read(*sb->alloc_hint);
35 if (unlikely(hint >= depth)) {
36 hint = depth ? get_random_u32_below(ceil: depth) : 0;
37 this_cpu_write(*sb->alloc_hint, hint);
38 }
39
40 return hint;
41}
42
43static inline void update_alloc_hint_after_get(struct sbitmap *sb,
44 unsigned int depth,
45 unsigned int hint,
46 unsigned int nr)
47{
48 if (nr == -1) {
49 /* If the map is full, a hint won't do us much good. */
50 this_cpu_write(*sb->alloc_hint, 0);
51 } else if (nr == hint || unlikely(sb->round_robin)) {
52 /* Only update the hint if we used it. */
53 hint = nr + 1;
54 if (hint >= depth - 1)
55 hint = 0;
56 this_cpu_write(*sb->alloc_hint, hint);
57 }
58}
59
60/*
61 * See if we have deferred clears that we can batch move
62 */
63static inline bool sbitmap_deferred_clear(struct sbitmap_word *map,
64 unsigned int depth, unsigned int alloc_hint, bool wrap)
65{
66 unsigned long mask, word_mask;
67
68 guard(raw_spinlock_irqsave)(l: &map->swap_lock);
69
70 if (!map->cleared) {
71 if (depth == 0)
72 return false;
73
74 word_mask = (~0UL) >> (BITS_PER_LONG - depth);
75 /*
76 * The current behavior is to always retry after moving
77 * ->cleared to word, and we change it to retry in case
78 * of any free bits. To avoid an infinite loop, we need
79 * to take wrap & alloc_hint into account, otherwise a
80 * soft lockup may occur.
81 */
82 if (!wrap && alloc_hint)
83 word_mask &= ~((1UL << alloc_hint) - 1);
84
85 return (READ_ONCE(map->word) & word_mask) != word_mask;
86 }
87
88 /*
89 * First get a stable cleared mask, setting the old mask to 0.
90 */
91 mask = xchg(&map->cleared, 0);
92
93 /*
94 * Now clear the masked bits in our free word
95 */
96 atomic_long_andnot(i: mask, v: (atomic_long_t *)&map->word);
97 BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
98 return true;
99}
100
101int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
102 gfp_t flags, int node, bool round_robin,
103 bool alloc_hint)
104{
105 unsigned int bits_per_word;
106 int i;
107
108 if (shift < 0)
109 shift = sbitmap_calculate_shift(depth);
110
111 bits_per_word = 1U << shift;
112 if (bits_per_word > BITS_PER_LONG)
113 return -EINVAL;
114
115 sb->shift = shift;
116 sb->depth = depth;
117 sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
118 sb->round_robin = round_robin;
119
120 if (depth == 0) {
121 sb->map = NULL;
122 return 0;
123 }
124
125 if (alloc_hint) {
126 if (init_alloc_hint(sb, flags))
127 return -ENOMEM;
128 } else {
129 sb->alloc_hint = NULL;
130 }
131
132 sb->map = kvzalloc_node(sb->map_nr * sizeof(*sb->map), flags, node);
133 if (!sb->map) {
134 free_percpu(pdata: sb->alloc_hint);
135 return -ENOMEM;
136 }
137
138 for (i = 0; i < sb->map_nr; i++)
139 raw_spin_lock_init(&sb->map[i].swap_lock);
140
141 return 0;
142}
143EXPORT_SYMBOL_GPL(sbitmap_init_node);
144
145void sbitmap_resize(struct sbitmap *sb, unsigned int depth)
146{
147 unsigned int bits_per_word = 1U << sb->shift;
148 unsigned int i;
149
150 for (i = 0; i < sb->map_nr; i++)
151 sbitmap_deferred_clear(map: &sb->map[i], depth: 0, alloc_hint: 0, wrap: 0);
152
153 sb->depth = depth;
154 sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
155}
156EXPORT_SYMBOL_GPL(sbitmap_resize);
157
158static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
159 unsigned int hint, bool wrap)
160{
161 int nr;
162
163 /* don't wrap if starting from 0 */
164 wrap = wrap && hint;
165
166 while (1) {
167 nr = find_next_zero_bit(addr: word, size: depth, offset: hint);
168 if (unlikely(nr >= depth)) {
169 /*
170 * We started with an offset, and we didn't reset the
171 * offset to 0 in a failure case, so start from 0 to
172 * exhaust the map.
173 */
174 if (hint && wrap) {
175 hint = 0;
176 continue;
177 }
178 return -1;
179 }
180
181 if (!test_and_set_bit_lock(nr, addr: word))
182 break;
183
184 hint = nr + 1;
185 if (hint >= depth - 1)
186 hint = 0;
187 }
188
189 return nr;
190}
191
192static int sbitmap_find_bit_in_word(struct sbitmap_word *map,
193 unsigned int depth,
194 unsigned int alloc_hint,
195 bool wrap)
196{
197 int nr;
198
199 do {
200 nr = __sbitmap_get_word(word: &map->word, depth,
201 hint: alloc_hint, wrap);
202 if (nr != -1)
203 break;
204 if (!sbitmap_deferred_clear(map, depth, alloc_hint, wrap))
205 break;
206 } while (1);
207
208 return nr;
209}
210
211static unsigned int __map_depth_with_shallow(const struct sbitmap *sb,
212 int index,
213 unsigned int shallow_depth)
214{
215 u64 shallow_word_depth;
216 unsigned int word_depth, reminder;
217
218 word_depth = __map_depth(sb, index);
219 if (shallow_depth >= sb->depth)
220 return word_depth;
221
222 shallow_word_depth = word_depth * shallow_depth;
223 reminder = do_div(shallow_word_depth, sb->depth);
224
225 if (reminder >= (index + 1) * word_depth)
226 shallow_word_depth++;
227
228 return (unsigned int)shallow_word_depth;
229}
230
231static int sbitmap_find_bit(struct sbitmap *sb,
232 unsigned int shallow_depth,
233 unsigned int index,
234 unsigned int alloc_hint,
235 bool wrap)
236{
237 unsigned int i;
238 int nr = -1;
239
240 for (i = 0; i < sb->map_nr; i++) {
241 unsigned int depth = __map_depth_with_shallow(sb, index,
242 shallow_depth);
243
244 if (depth)
245 nr = sbitmap_find_bit_in_word(map: &sb->map[index], depth,
246 alloc_hint, wrap);
247 if (nr != -1) {
248 nr += index << sb->shift;
249 break;
250 }
251
252 /* Jump to next index. */
253 alloc_hint = 0;
254 if (++index >= sb->map_nr)
255 index = 0;
256 }
257
258 return nr;
259}
260
261static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
262{
263 unsigned int index;
264
265 index = SB_NR_TO_INDEX(sb, alloc_hint);
266
267 /*
268 * Unless we're doing round robin tag allocation, just use the
269 * alloc_hint to find the right word index. No point in looping
270 * twice in find_next_zero_bit() for that case.
271 */
272 if (sb->round_robin)
273 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
274 else
275 alloc_hint = 0;
276
277 return sbitmap_find_bit(sb, UINT_MAX, index, alloc_hint,
278 wrap: !sb->round_robin);
279}
280
281int sbitmap_get(struct sbitmap *sb)
282{
283 int nr;
284 unsigned int hint, depth;
285
286 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
287 return -1;
288
289 depth = READ_ONCE(sb->depth);
290 hint = update_alloc_hint_before_get(sb, depth);
291 nr = __sbitmap_get(sb, alloc_hint: hint);
292 update_alloc_hint_after_get(sb, depth, hint, nr);
293
294 return nr;
295}
296EXPORT_SYMBOL_GPL(sbitmap_get);
297
298static int __sbitmap_get_shallow(struct sbitmap *sb,
299 unsigned int alloc_hint,
300 unsigned long shallow_depth)
301{
302 unsigned int index;
303
304 index = SB_NR_TO_INDEX(sb, alloc_hint);
305 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
306
307 return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, wrap: true);
308}
309
310/**
311 * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap,
312 * limiting the depth used from each word.
313 * @sb: Bitmap to allocate from.
314 * @shallow_depth: The maximum number of bits to allocate from the bitmap.
315 *
316 * This rather specific operation allows for having multiple users with
317 * different allocation limits. E.g., there can be a high-priority class that
318 * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow()
319 * with a @shallow_depth of (sb->depth >> 1). Then, the low-priority
320 * class can only allocate half of the total bits in the bitmap, preventing it
321 * from starving out the high-priority class.
322 *
323 * Return: Non-negative allocated bit number if successful, -1 otherwise.
324 */
325static int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
326{
327 int nr;
328 unsigned int hint, depth;
329
330 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
331 return -1;
332
333 depth = READ_ONCE(sb->depth);
334 hint = update_alloc_hint_before_get(sb, depth);
335 nr = __sbitmap_get_shallow(sb, alloc_hint: hint, shallow_depth);
336 update_alloc_hint_after_get(sb, depth, hint, nr);
337
338 return nr;
339}
340
341bool sbitmap_any_bit_set(const struct sbitmap *sb)
342{
343 unsigned int i;
344
345 for (i = 0; i < sb->map_nr; i++) {
346 if (sb->map[i].word & ~sb->map[i].cleared)
347 return true;
348 }
349 return false;
350}
351EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
352
353static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
354{
355 unsigned int i, weight = 0;
356
357 for (i = 0; i < sb->map_nr; i++) {
358 const struct sbitmap_word *word = &sb->map[i];
359 unsigned int word_depth = __map_depth(sb, index: i);
360
361 if (set)
362 weight += bitmap_weight(src: &word->word, nbits: word_depth);
363 else
364 weight += bitmap_weight(src: &word->cleared, nbits: word_depth);
365 }
366 return weight;
367}
368
369static unsigned int sbitmap_cleared(const struct sbitmap *sb)
370{
371 return __sbitmap_weight(sb, set: false);
372}
373
374unsigned int sbitmap_weight(const struct sbitmap *sb)
375{
376 return __sbitmap_weight(sb, set: true) - sbitmap_cleared(sb);
377}
378EXPORT_SYMBOL_GPL(sbitmap_weight);
379
380void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
381{
382 seq_printf(m, fmt: "depth=%u\n", sb->depth);
383 seq_printf(m, fmt: "busy=%u\n", sbitmap_weight(sb));
384 seq_printf(m, fmt: "cleared=%u\n", sbitmap_cleared(sb));
385 seq_printf(m, fmt: "bits_per_word=%u\n", 1U << sb->shift);
386 seq_printf(m, fmt: "map_nr=%u\n", sb->map_nr);
387}
388EXPORT_SYMBOL_GPL(sbitmap_show);
389
390static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
391{
392 if ((offset & 0xf) == 0) {
393 if (offset != 0)
394 seq_putc(m, c: '\n');
395 seq_printf(m, fmt: "%08x:", offset);
396 }
397 if ((offset & 0x1) == 0)
398 seq_putc(m, c: ' ');
399 seq_printf(m, fmt: "%02x", byte);
400}
401
402void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
403{
404 u8 byte = 0;
405 unsigned int byte_bits = 0;
406 unsigned int offset = 0;
407 int i;
408
409 for (i = 0; i < sb->map_nr; i++) {
410 unsigned long word = READ_ONCE(sb->map[i].word);
411 unsigned long cleared = READ_ONCE(sb->map[i].cleared);
412 unsigned int word_bits = __map_depth(sb, index: i);
413
414 word &= ~cleared;
415
416 while (word_bits > 0) {
417 unsigned int bits = min(8 - byte_bits, word_bits);
418
419 byte |= (word & (BIT(bits) - 1)) << byte_bits;
420 byte_bits += bits;
421 if (byte_bits == 8) {
422 emit_byte(m, offset, byte);
423 byte = 0;
424 byte_bits = 0;
425 offset++;
426 }
427 word >>= bits;
428 word_bits -= bits;
429 }
430 }
431 if (byte_bits) {
432 emit_byte(m, offset, byte);
433 offset++;
434 }
435 if (offset)
436 seq_putc(m, c: '\n');
437}
438EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
439
440static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
441 unsigned int depth)
442{
443 return clamp_t(unsigned int,
444 min(depth, sbq->min_shallow_depth) / SBQ_WAIT_QUEUES,
445 1, SBQ_WAKE_BATCH);
446}
447
448int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
449 int shift, bool round_robin, gfp_t flags, int node)
450{
451 int ret;
452 int i;
453
454 ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
455 round_robin, true);
456 if (ret)
457 return ret;
458
459 sbq->min_shallow_depth = UINT_MAX;
460 sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
461 atomic_set(v: &sbq->wake_index, i: 0);
462 atomic_set(v: &sbq->ws_active, i: 0);
463 atomic_set(v: &sbq->completion_cnt, i: 0);
464 atomic_set(v: &sbq->wakeup_cnt, i: 0);
465
466 sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
467 if (!sbq->ws) {
468 sbitmap_free(sb: &sbq->sb);
469 return -ENOMEM;
470 }
471
472 for (i = 0; i < SBQ_WAIT_QUEUES; i++)
473 init_waitqueue_head(&sbq->ws[i].wait);
474
475 return 0;
476}
477EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
478
479static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
480 unsigned int depth)
481{
482 unsigned int wake_batch;
483
484 wake_batch = sbq_calc_wake_batch(sbq, depth);
485 if (sbq->wake_batch != wake_batch)
486 WRITE_ONCE(sbq->wake_batch, wake_batch);
487}
488
489void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
490 unsigned int users)
491{
492 unsigned int wake_batch;
493 unsigned int depth = (sbq->sb.depth + users - 1) / users;
494
495 wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
496 1, SBQ_WAKE_BATCH);
497
498 WRITE_ONCE(sbq->wake_batch, wake_batch);
499}
500EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
501
502void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
503{
504 sbitmap_queue_update_wake_batch(sbq, depth);
505 sbitmap_resize(&sbq->sb, depth);
506}
507EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
508
509int __sbitmap_queue_get(struct sbitmap_queue *sbq)
510{
511 return sbitmap_get(&sbq->sb);
512}
513EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
514
515unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
516 unsigned int *offset)
517{
518 struct sbitmap *sb = &sbq->sb;
519 unsigned int hint, depth;
520 unsigned long index, nr;
521 int i;
522
523 if (unlikely(sb->round_robin))
524 return 0;
525
526 depth = READ_ONCE(sb->depth);
527 hint = update_alloc_hint_before_get(sb, depth);
528
529 index = SB_NR_TO_INDEX(sb, hint);
530
531 for (i = 0; i < sb->map_nr; i++) {
532 struct sbitmap_word *map = &sb->map[index];
533 unsigned long get_mask;
534 unsigned int map_depth = __map_depth(sb, index);
535 unsigned long val;
536
537 sbitmap_deferred_clear(map, depth: 0, alloc_hint: 0, wrap: 0);
538 val = READ_ONCE(map->word);
539 if (val == (1UL << (map_depth - 1)) - 1)
540 goto next;
541
542 nr = find_first_zero_bit(addr: &val, size: map_depth);
543 if (nr + nr_tags <= map_depth) {
544 atomic_long_t *ptr = (atomic_long_t *) &map->word;
545
546 get_mask = ((1UL << nr_tags) - 1) << nr;
547 while (!atomic_long_try_cmpxchg(v: ptr, old: &val,
548 new: get_mask | val))
549 ;
550 get_mask = (get_mask & ~val) >> nr;
551 if (get_mask) {
552 *offset = nr + (index << sb->shift);
553 update_alloc_hint_after_get(sb, depth, hint,
554 nr: *offset + nr_tags - 1);
555 return get_mask;
556 }
557 }
558next:
559 /* Jump to next index. */
560 if (++index >= sb->map_nr)
561 index = 0;
562 }
563
564 return 0;
565}
566
567int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
568 unsigned int shallow_depth)
569{
570 WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
571
572 return sbitmap_get_shallow(sb: &sbq->sb, shallow_depth);
573}
574EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow);
575
576void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
577 unsigned int min_shallow_depth)
578{
579 sbq->min_shallow_depth = min_shallow_depth;
580 sbitmap_queue_update_wake_batch(sbq, depth: sbq->sb.depth);
581}
582EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
583
584static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
585{
586 int i, wake_index, woken;
587
588 if (!atomic_read(v: &sbq->ws_active))
589 return;
590
591 wake_index = atomic_read(v: &sbq->wake_index);
592 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
593 struct sbq_wait_state *ws = &sbq->ws[wake_index];
594
595 /*
596 * Advance the index before checking the current queue.
597 * It improves fairness, by ensuring the queue doesn't
598 * need to be fully emptied before trying to wake up
599 * from the next one.
600 */
601 wake_index = sbq_index_inc(index: wake_index);
602
603 if (waitqueue_active(wq_head: &ws->wait)) {
604 woken = wake_up_nr(&ws->wait, nr);
605 if (woken == nr)
606 break;
607 nr -= woken;
608 }
609 }
610
611 if (wake_index != atomic_read(v: &sbq->wake_index))
612 atomic_set(v: &sbq->wake_index, i: wake_index);
613}
614
615void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
616{
617 unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
618 unsigned int wakeups;
619
620 if (!atomic_read(v: &sbq->ws_active))
621 return;
622
623 atomic_add(i: nr, v: &sbq->completion_cnt);
624 wakeups = atomic_read(v: &sbq->wakeup_cnt);
625
626 do {
627 if (atomic_read(v: &sbq->completion_cnt) - wakeups < wake_batch)
628 return;
629 } while (!atomic_try_cmpxchg(v: &sbq->wakeup_cnt,
630 old: &wakeups, new: wakeups + wake_batch));
631
632 __sbitmap_queue_wake_up(sbq, nr: wake_batch);
633}
634EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
635
636static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
637{
638 if (likely(!sb->round_robin && tag < sb->depth))
639 data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
640}
641
642void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
643 int *tags, int nr_tags)
644{
645 struct sbitmap *sb = &sbq->sb;
646 unsigned long *addr = NULL;
647 unsigned long mask = 0;
648 int i;
649
650 smp_mb__before_atomic();
651 for (i = 0; i < nr_tags; i++) {
652 const int tag = tags[i] - offset;
653 unsigned long *this_addr;
654
655 /* since we're clearing a batch, skip the deferred map */
656 this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
657 if (!addr) {
658 addr = this_addr;
659 } else if (addr != this_addr) {
660 atomic_long_andnot(i: mask, v: (atomic_long_t *) addr);
661 mask = 0;
662 addr = this_addr;
663 }
664 mask |= (1UL << SB_NR_TO_BIT(sb, tag));
665 }
666
667 if (mask)
668 atomic_long_andnot(i: mask, v: (atomic_long_t *) addr);
669
670 smp_mb__after_atomic();
671 sbitmap_queue_wake_up(sbq, nr_tags);
672 sbitmap_update_cpu_hint(sb: &sbq->sb, raw_smp_processor_id(),
673 tag: tags[nr_tags - 1] - offset);
674}
675
676void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
677 unsigned int cpu)
678{
679 /*
680 * Once the clear bit is set, the bit may be allocated out.
681 *
682 * Orders READ/WRITE on the associated instance(such as request
683 * of blk_mq) by this bit for avoiding race with re-allocation,
684 * and its pair is the memory barrier implied in __sbitmap_get_word.
685 *
686 * One invariant is that the clear bit has to be zero when the bit
687 * is in use.
688 */
689 smp_mb__before_atomic();
690 sbitmap_deferred_clear_bit(sb: &sbq->sb, bitnr: nr);
691
692 /*
693 * Pairs with the memory barrier in set_current_state() to ensure the
694 * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
695 * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
696 * waiter. See the comment on waitqueue_active().
697 */
698 smp_mb__after_atomic();
699 sbitmap_queue_wake_up(sbq, 1);
700 sbitmap_update_cpu_hint(sb: &sbq->sb, cpu, tag: nr);
701}
702EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
703
704void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
705{
706 int i, wake_index;
707
708 /*
709 * Pairs with the memory barrier in set_current_state() like in
710 * sbitmap_queue_wake_up().
711 */
712 smp_mb();
713 wake_index = atomic_read(v: &sbq->wake_index);
714 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
715 struct sbq_wait_state *ws = &sbq->ws[wake_index];
716
717 if (waitqueue_active(wq_head: &ws->wait))
718 wake_up(&ws->wait);
719
720 wake_index = sbq_index_inc(index: wake_index);
721 }
722}
723EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
724
725void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
726{
727 bool first;
728 int i;
729
730 sbitmap_show(&sbq->sb, m);
731
732 seq_puts(m, s: "alloc_hint={");
733 first = true;
734 for_each_possible_cpu(i) {
735 if (!first)
736 seq_puts(m, s: ", ");
737 first = false;
738 seq_printf(m, fmt: "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
739 }
740 seq_puts(m, s: "}\n");
741
742 seq_printf(m, fmt: "wake_batch=%u\n", sbq->wake_batch);
743 seq_printf(m, fmt: "wake_index=%d\n", atomic_read(v: &sbq->wake_index));
744 seq_printf(m, fmt: "ws_active=%d\n", atomic_read(v: &sbq->ws_active));
745
746 seq_puts(m, s: "ws={\n");
747 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
748 struct sbq_wait_state *ws = &sbq->ws[i];
749 seq_printf(m, fmt: "\t{.wait=%s},\n",
750 waitqueue_active(wq_head: &ws->wait) ? "active" : "inactive");
751 }
752 seq_puts(m, s: "}\n");
753
754 seq_printf(m, fmt: "round_robin=%d\n", sbq->sb.round_robin);
755 seq_printf(m, fmt: "min_shallow_depth=%u\n", sbq->min_shallow_depth);
756}
757EXPORT_SYMBOL_GPL(sbitmap_queue_show);
758
759void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
760 struct sbq_wait_state *ws,
761 struct sbq_wait *sbq_wait)
762{
763 if (!sbq_wait->sbq) {
764 sbq_wait->sbq = sbq;
765 atomic_inc(v: &sbq->ws_active);
766 add_wait_queue(wq_head: &ws->wait, wq_entry: &sbq_wait->wait);
767 }
768}
769EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
770
771void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
772{
773 list_del_init(entry: &sbq_wait->wait.entry);
774 if (sbq_wait->sbq) {
775 atomic_dec(v: &sbq_wait->sbq->ws_active);
776 sbq_wait->sbq = NULL;
777 }
778}
779EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
780
781void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
782 struct sbq_wait_state *ws,
783 struct sbq_wait *sbq_wait, int state)
784{
785 if (!sbq_wait->sbq) {
786 atomic_inc(v: &sbq->ws_active);
787 sbq_wait->sbq = sbq;
788 }
789 prepare_to_wait_exclusive(wq_head: &ws->wait, wq_entry: &sbq_wait->wait, state);
790}
791EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
792
793void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
794 struct sbq_wait *sbq_wait)
795{
796 finish_wait(wq_head: &ws->wait, wq_entry: &sbq_wait->wait);
797 if (sbq_wait->sbq) {
798 atomic_dec(v: &sbq->ws_active);
799 sbq_wait->sbq = NULL;
800 }
801}
802EXPORT_SYMBOL_GPL(sbitmap_finish_wait);
803

source code of linux/lib/sbitmap.c