sbitmap.c

  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 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(&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				!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, 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, 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, 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, i);
360
361		if (set)
362			weight += bitmap_weight(&word->word, word_depth);
363		else
364			weight += bitmap_weight(&word->cleared, word_depth);
365	}
366	return weight;
367}
368
369static unsigned int sbitmap_cleared(const struct sbitmap *sb)
370{
371	return __sbitmap_weight(sb, false);
372}
373
374unsigned int sbitmap_weight(const struct sbitmap *sb)
375{
376	return __sbitmap_weight(sb, 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, "depth=%u\n", sb->depth);
383	seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
384	seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
385	seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
386	seq_printf(m, "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, '\n');
395		seq_printf(m, "%08x:", offset);
396	}
397	if ((offset & 0x1) == 0)
398		seq_putc(m, ' ');
399	seq_printf(m, "%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, 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, '\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(&sbq->wake_index, 0);
462	atomic_set(&sbq->ws_active, 0);
463	atomic_set(&sbq->completion_cnt, 0);
464	atomic_set(&sbq->wakeup_cnt, 0);
465
466	sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
467	if (!sbq->ws) {
468		sbitmap_free(&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, 0, 0, 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(&val, 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(ptr, &val,
548							  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							*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(&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, 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(&sbq->ws_active))
589		return;
590
591	wake_index = atomic_read(&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(wake_index);
602
603		if (waitqueue_active(&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(&sbq->wake_index))
612		atomic_set(&sbq->wake_index, 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(&sbq->ws_active))
621		return;
622
623	atomic_add(nr, &sbq->completion_cnt);
624	wakeups = atomic_read(&sbq->wakeup_cnt);
625
626	do {
627		if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch)
628			return;
629	} while (!atomic_try_cmpxchg(&sbq->wakeup_cnt,
630				     &wakeups, wakeups + wake_batch));
631
632	__sbitmap_queue_wake_up(sbq, 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(mask, (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(mask, (atomic_long_t *) addr);
669
670	smp_mb__after_atomic();
671	sbitmap_queue_wake_up(sbq, nr_tags);
672	sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
673					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(&sbq->sb, 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(&sbq->sb, cpu, 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(&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(&ws->wait))
718			wake_up(&ws->wait);
719
720		wake_index = sbq_index_inc(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, "alloc_hint={");
733	first = true;
734	for_each_possible_cpu(i) {
735		if (!first)
736			seq_puts(m, ", ");
737		first = false;
738		seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
739	}
740	seq_puts(m, "}\n");
741
742	seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
743	seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
744	seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
745
746	seq_puts(m, "ws={\n");
747	for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
748		struct sbq_wait_state *ws = &sbq->ws[i];
749		seq_printf(m, "\t{.wait=%s},\n",
750			   waitqueue_active(&ws->wait) ? "active" : "inactive");
751	}
752	seq_puts(m, "}\n");
753
754	seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
755	seq_printf(m, "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(&sbq->ws_active);
766		add_wait_queue(&ws->wait, &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(&sbq_wait->wait.entry);
774	if (sbq_wait->sbq) {
775		atomic_dec(&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(&sbq->ws_active);
787		sbq_wait->sbq = sbq;
788	}
789	prepare_to_wait_exclusive(&ws->wait, &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(&ws->wait, &sbq_wait->wait);
797	if (sbq_wait->sbq) {
798		atomic_dec(&sbq->ws_active);
799		sbq_wait->sbq = NULL;
800	}
801}
802EXPORT_SYMBOL_GPL(sbitmap_finish_wait);