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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(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(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)(&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(mask, (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(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(&sb->map[i], 0, 0, 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(word, depth, 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, 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(&map->word, depth,
201 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 int sbitmap_find_bit(struct sbitmap *sb,
212 unsigned int depth,
213 unsigned int index,
214 unsigned int alloc_hint,
215 bool wrap)
216{
217 unsigned int i;
218 int nr = -1;
219
220 for (i = 0; i < sb->map_nr; i++) {
221 nr = sbitmap_find_bit_in_word(&sb->map[index],
222 min_t(unsigned int,
223 __map_depth(sb, index),
224 depth),
225 alloc_hint, wrap);
226
227 if (nr != -1) {
228 nr += index << sb->shift;
229 break;
230 }
231
232 /* Jump to next index. */
233 alloc_hint = 0;
234 if (++index >= sb->map_nr)
235 index = 0;
236 }
237
238 return nr;
239}
240
241static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
242{
243 unsigned int index;
244
245 index = SB_NR_TO_INDEX(sb, alloc_hint);
246
247 /*
248 * Unless we're doing round robin tag allocation, just use the
249 * alloc_hint to find the right word index. No point in looping
250 * twice in find_next_zero_bit() for that case.
251 */
252 if (sb->round_robin)
253 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
254 else
255 alloc_hint = 0;
256
257 return sbitmap_find_bit(sb, UINT_MAX, index, alloc_hint,
258 !sb->round_robin);
259}
260
261int sbitmap_get(struct sbitmap *sb)
262{
263 int nr;
264 unsigned int hint, depth;
265
266 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
267 return -1;
268
269 depth = READ_ONCE(sb->depth);
270 hint = update_alloc_hint_before_get(sb, depth);
271 nr = __sbitmap_get(sb, hint);
272 update_alloc_hint_after_get(sb, depth, hint, nr);
273
274 return nr;
275}
276EXPORT_SYMBOL_GPL(sbitmap_get);
277
278static int __sbitmap_get_shallow(struct sbitmap *sb,
279 unsigned int alloc_hint,
280 unsigned long shallow_depth)
281{
282 unsigned int index;
283
284 index = SB_NR_TO_INDEX(sb, alloc_hint);
285 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
286
287 return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true);
288}
289
290int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
291{
292 int nr;
293 unsigned int hint, depth;
294
295 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
296 return -1;
297
298 depth = READ_ONCE(sb->depth);
299 hint = update_alloc_hint_before_get(sb, depth);
300 nr = __sbitmap_get_shallow(sb, hint, shallow_depth);
301 update_alloc_hint_after_get(sb, depth, hint, nr);
302
303 return nr;
304}
305EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
306
307bool sbitmap_any_bit_set(const struct sbitmap *sb)
308{
309 unsigned int i;
310
311 for (i = 0; i < sb->map_nr; i++) {
312 if (sb->map[i].word & ~sb->map[i].cleared)
313 return true;
314 }
315 return false;
316}
317EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
318
319static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
320{
321 unsigned int i, weight = 0;
322
323 for (i = 0; i < sb->map_nr; i++) {
324 const struct sbitmap_word *word = &sb->map[i];
325 unsigned int word_depth = __map_depth(sb, i);
326
327 if (set)
328 weight += bitmap_weight(&word->word, word_depth);
329 else
330 weight += bitmap_weight(&word->cleared, word_depth);
331 }
332 return weight;
333}
334
335static unsigned int sbitmap_cleared(const struct sbitmap *sb)
336{
337 return __sbitmap_weight(sb, false);
338}
339
340unsigned int sbitmap_weight(const struct sbitmap *sb)
341{
342 return __sbitmap_weight(sb, true) - sbitmap_cleared(sb);
343}
344EXPORT_SYMBOL_GPL(sbitmap_weight);
345
346void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
347{
348 seq_printf(m, "depth=%u\n", sb->depth);
349 seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
350 seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
351 seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
352 seq_printf(m, "map_nr=%u\n", sb->map_nr);
353}
354EXPORT_SYMBOL_GPL(sbitmap_show);
355
356static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
357{
358 if ((offset & 0xf) == 0) {
359 if (offset != 0)
360 seq_putc(m, '\n');
361 seq_printf(m, "%08x:", offset);
362 }
363 if ((offset & 0x1) == 0)
364 seq_putc(m, ' ');
365 seq_printf(m, "%02x", byte);
366}
367
368void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
369{
370 u8 byte = 0;
371 unsigned int byte_bits = 0;
372 unsigned int offset = 0;
373 int i;
374
375 for (i = 0; i < sb->map_nr; i++) {
376 unsigned long word = READ_ONCE(sb->map[i].word);
377 unsigned long cleared = READ_ONCE(sb->map[i].cleared);
378 unsigned int word_bits = __map_depth(sb, i);
379
380 word &= ~cleared;
381
382 while (word_bits > 0) {
383 unsigned int bits = min(8 - byte_bits, word_bits);
384
385 byte |= (word & (BIT(bits) - 1)) << byte_bits;
386 byte_bits += bits;
387 if (byte_bits == 8) {
388 emit_byte(m, offset, byte);
389 byte = 0;
390 byte_bits = 0;
391 offset++;
392 }
393 word >>= bits;
394 word_bits -= bits;
395 }
396 }
397 if (byte_bits) {
398 emit_byte(m, offset, byte);
399 offset++;
400 }
401 if (offset)
402 seq_putc(m, '\n');
403}
404EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
405
406static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
407 unsigned int depth)
408{
409 unsigned int wake_batch;
410 unsigned int shallow_depth;
411
412 /*
413 * Each full word of the bitmap has bits_per_word bits, and there might
414 * be a partial word. There are depth / bits_per_word full words and
415 * depth % bits_per_word bits left over. In bitwise arithmetic:
416 *
417 * bits_per_word = 1 << shift
418 * depth / bits_per_word = depth >> shift
419 * depth % bits_per_word = depth & ((1 << shift) - 1)
420 *
421 * Each word can be limited to sbq->min_shallow_depth bits.
422 */
423 shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth);
424 depth = ((depth >> sbq->sb.shift) * shallow_depth +
425 min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth));
426 wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1,
427 SBQ_WAKE_BATCH);
428
429 return wake_batch;
430}
431
432int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
433 int shift, bool round_robin, gfp_t flags, int node)
434{
435 int ret;
436 int i;
437
438 ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
439 round_robin, true);
440 if (ret)
441 return ret;
442
443 sbq->min_shallow_depth = UINT_MAX;
444 sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
445 atomic_set(&sbq->wake_index, 0);
446 atomic_set(&sbq->ws_active, 0);
447 atomic_set(&sbq->completion_cnt, 0);
448 atomic_set(&sbq->wakeup_cnt, 0);
449
450 sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
451 if (!sbq->ws) {
452 sbitmap_free(&sbq->sb);
453 return -ENOMEM;
454 }
455
456 for (i = 0; i < SBQ_WAIT_QUEUES; i++)
457 init_waitqueue_head(&sbq->ws[i].wait);
458
459 return 0;
460}
461EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
462
463static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
464 unsigned int depth)
465{
466 unsigned int wake_batch;
467
468 wake_batch = sbq_calc_wake_batch(sbq, depth);
469 if (sbq->wake_batch != wake_batch)
470 WRITE_ONCE(sbq->wake_batch, wake_batch);
471}
472
473void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
474 unsigned int users)
475{
476 unsigned int wake_batch;
477 unsigned int depth = (sbq->sb.depth + users - 1) / users;
478
479 wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
480 1, SBQ_WAKE_BATCH);
481
482 WRITE_ONCE(sbq->wake_batch, wake_batch);
483}
484EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
485
486void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
487{
488 sbitmap_queue_update_wake_batch(sbq, depth);
489 sbitmap_resize(&sbq->sb, depth);
490}
491EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
492
493int __sbitmap_queue_get(struct sbitmap_queue *sbq)
494{
495 return sbitmap_get(&sbq->sb);
496}
497EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
498
499unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
500 unsigned int *offset)
501{
502 struct sbitmap *sb = &sbq->sb;
503 unsigned int hint, depth;
504 unsigned long index, nr;
505 int i;
506
507 if (unlikely(sb->round_robin))
508 return 0;
509
510 depth = READ_ONCE(sb->depth);
511 hint = update_alloc_hint_before_get(sb, depth);
512
513 index = SB_NR_TO_INDEX(sb, hint);
514
515 for (i = 0; i < sb->map_nr; i++) {
516 struct sbitmap_word *map = &sb->map[index];
517 unsigned long get_mask;
518 unsigned int map_depth = __map_depth(sb, index);
519 unsigned long val;
520
521 sbitmap_deferred_clear(map, 0, 0, 0);
522 val = READ_ONCE(map->word);
523 if (val == (1UL << (map_depth - 1)) - 1)
524 goto next;
525
526 nr = find_first_zero_bit(&val, map_depth);
527 if (nr + nr_tags <= map_depth) {
528 atomic_long_t *ptr = (atomic_long_t *) &map->word;
529
530 get_mask = ((1UL << nr_tags) - 1) << nr;
531 while (!atomic_long_try_cmpxchg(ptr, &val,
532 get_mask | val))
533 ;
534 get_mask = (get_mask & ~val) >> nr;
535 if (get_mask) {
536 *offset = nr + (index << sb->shift);
537 update_alloc_hint_after_get(sb, depth, hint,
538 *offset + nr_tags - 1);
539 return get_mask;
540 }
541 }
542next:
543 /* Jump to next index. */
544 if (++index >= sb->map_nr)
545 index = 0;
546 }
547
548 return 0;
549}
550
551int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
552 unsigned int shallow_depth)
553{
554 WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
555
556 return sbitmap_get_shallow(&sbq->sb, shallow_depth);
557}
558EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow);
559
560void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
561 unsigned int min_shallow_depth)
562{
563 sbq->min_shallow_depth = min_shallow_depth;
564 sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth);
565}
566EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
567
568static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
569{
570 int i, wake_index, woken;
571
572 if (!atomic_read(&sbq->ws_active))
573 return;
574
575 wake_index = atomic_read(&sbq->wake_index);
576 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
577 struct sbq_wait_state *ws = &sbq->ws[wake_index];
578
579 /*
580 * Advance the index before checking the current queue.
581 * It improves fairness, by ensuring the queue doesn't
582 * need to be fully emptied before trying to wake up
583 * from the next one.
584 */
585 wake_index = sbq_index_inc(wake_index);
586
587 if (waitqueue_active(&ws->wait)) {
588 woken = wake_up_nr(&ws->wait, nr);
589 if (woken == nr)
590 break;
591 nr -= woken;
592 }
593 }
594
595 if (wake_index != atomic_read(&sbq->wake_index))
596 atomic_set(&sbq->wake_index, wake_index);
597}
598
599void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
600{
601 unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
602 unsigned int wakeups;
603
604 if (!atomic_read(&sbq->ws_active))
605 return;
606
607 atomic_add(nr, &sbq->completion_cnt);
608 wakeups = atomic_read(&sbq->wakeup_cnt);
609
610 do {
611 if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch)
612 return;
613 } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt,
614 &wakeups, wakeups + wake_batch));
615
616 __sbitmap_queue_wake_up(sbq, wake_batch);
617}
618EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
619
620static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
621{
622 if (likely(!sb->round_robin && tag < sb->depth))
623 data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
624}
625
626void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
627 int *tags, int nr_tags)
628{
629 struct sbitmap *sb = &sbq->sb;
630 unsigned long *addr = NULL;
631 unsigned long mask = 0;
632 int i;
633
634 smp_mb__before_atomic();
635 for (i = 0; i < nr_tags; i++) {
636 const int tag = tags[i] - offset;
637 unsigned long *this_addr;
638
639 /* since we're clearing a batch, skip the deferred map */
640 this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
641 if (!addr) {
642 addr = this_addr;
643 } else if (addr != this_addr) {
644 atomic_long_andnot(mask, (atomic_long_t *) addr);
645 mask = 0;
646 addr = this_addr;
647 }
648 mask |= (1UL << SB_NR_TO_BIT(sb, tag));
649 }
650
651 if (mask)
652 atomic_long_andnot(mask, (atomic_long_t *) addr);
653
654 smp_mb__after_atomic();
655 sbitmap_queue_wake_up(sbq, nr_tags);
656 sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
657 tags[nr_tags - 1] - offset);
658}
659
660void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
661 unsigned int cpu)
662{
663 /*
664 * Once the clear bit is set, the bit may be allocated out.
665 *
666 * Orders READ/WRITE on the associated instance(such as request
667 * of blk_mq) by this bit for avoiding race with re-allocation,
668 * and its pair is the memory barrier implied in __sbitmap_get_word.
669 *
670 * One invariant is that the clear bit has to be zero when the bit
671 * is in use.
672 */
673 smp_mb__before_atomic();
674 sbitmap_deferred_clear_bit(&sbq->sb, nr);
675
676 /*
677 * Pairs with the memory barrier in set_current_state() to ensure the
678 * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
679 * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
680 * waiter. See the comment on waitqueue_active().
681 */
682 smp_mb__after_atomic();
683 sbitmap_queue_wake_up(sbq, 1);
684 sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
685}
686EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
687
688void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
689{
690 int i, wake_index;
691
692 /*
693 * Pairs with the memory barrier in set_current_state() like in
694 * sbitmap_queue_wake_up().
695 */
696 smp_mb();
697 wake_index = atomic_read(&sbq->wake_index);
698 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
699 struct sbq_wait_state *ws = &sbq->ws[wake_index];
700
701 if (waitqueue_active(&ws->wait))
702 wake_up(&ws->wait);
703
704 wake_index = sbq_index_inc(wake_index);
705 }
706}
707EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
708
709void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
710{
711 bool first;
712 int i;
713
714 sbitmap_show(&sbq->sb, m);
715
716 seq_puts(m, "alloc_hint={");
717 first = true;
718 for_each_possible_cpu(i) {
719 if (!first)
720 seq_puts(m, ", ");
721 first = false;
722 seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
723 }
724 seq_puts(m, "}\n");
725
726 seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
727 seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
728 seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
729
730 seq_puts(m, "ws={\n");
731 for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
732 struct sbq_wait_state *ws = &sbq->ws[i];
733 seq_printf(m, "\t{.wait=%s},\n",
734 waitqueue_active(&ws->wait) ? "active" : "inactive");
735 }
736 seq_puts(m, "}\n");
737
738 seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
739 seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
740}
741EXPORT_SYMBOL_GPL(sbitmap_queue_show);
742
743void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
744 struct sbq_wait_state *ws,
745 struct sbq_wait *sbq_wait)
746{
747 if (!sbq_wait->sbq) {
748 sbq_wait->sbq = sbq;
749 atomic_inc(&sbq->ws_active);
750 add_wait_queue(&ws->wait, &sbq_wait->wait);
751 }
752}
753EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
754
755void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
756{
757 list_del_init(&sbq_wait->wait.entry);
758 if (sbq_wait->sbq) {
759 atomic_dec(&sbq_wait->sbq->ws_active);
760 sbq_wait->sbq = NULL;
761 }
762}
763EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
764
765void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
766 struct sbq_wait_state *ws,
767 struct sbq_wait *sbq_wait, int state)
768{
769 if (!sbq_wait->sbq) {
770 atomic_inc(&sbq->ws_active);
771 sbq_wait->sbq = sbq;
772 }
773 prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
774}
775EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
776
777void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
778 struct sbq_wait *sbq_wait)
779{
780 finish_wait(&ws->wait, &sbq_wait->wait);
781 if (sbq_wait->sbq) {
782 atomic_dec(&sbq->ws_active);
783 sbq_wait->sbq = NULL;
784 }
785}
786EXPORT_SYMBOL_GPL(sbitmap_finish_wait);