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9#include <linux/kernel.h>
10#include <linux/module.h>
11
12#include <linux/blk-mq.h>
13#include <linux/delay.h>
14#include "blk.h"
15#include "blk-mq.h"
16#include "blk-mq-sched.h"
17#include "blk-mq-tag.h"
18
19
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24
25bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
26{
27 if (blk_mq_is_sbitmap_shared(hctx->flags)) {
28 struct request_queue *q = hctx->queue;
29 struct blk_mq_tag_set *set = q->tag_set;
30
31 if (!test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) &&
32 !test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
33 atomic_inc(&set->active_queues_shared_sbitmap);
34 } else {
35 if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
36 !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
37 atomic_inc(&hctx->tags->active_queues);
38 }
39
40 return true;
41}
42
43
44
45
46void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
47{
48 sbitmap_queue_wake_all(tags->bitmap_tags);
49 if (include_reserve)
50 sbitmap_queue_wake_all(tags->breserved_tags);
51}
52
53
54
55
56
57void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
58{
59 struct blk_mq_tags *tags = hctx->tags;
60 struct request_queue *q = hctx->queue;
61 struct blk_mq_tag_set *set = q->tag_set;
62
63 if (blk_mq_is_sbitmap_shared(hctx->flags)) {
64 if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
65 &q->queue_flags))
66 return;
67 atomic_dec(&set->active_queues_shared_sbitmap);
68 } else {
69 if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
70 return;
71 atomic_dec(&tags->active_queues);
72 }
73
74 blk_mq_tag_wakeup_all(tags, false);
75}
76
77static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
78 struct sbitmap_queue *bt)
79{
80 if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
81 !hctx_may_queue(data->hctx, bt))
82 return BLK_MQ_NO_TAG;
83
84 if (data->shallow_depth)
85 return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
86 else
87 return __sbitmap_queue_get(bt);
88}
89
90unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
91{
92 struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
93 struct sbitmap_queue *bt;
94 struct sbq_wait_state *ws;
95 DEFINE_SBQ_WAIT(wait);
96 unsigned int tag_offset;
97 int tag;
98
99 if (data->flags & BLK_MQ_REQ_RESERVED) {
100 if (unlikely(!tags->nr_reserved_tags)) {
101 WARN_ON_ONCE(1);
102 return BLK_MQ_NO_TAG;
103 }
104 bt = tags->breserved_tags;
105 tag_offset = 0;
106 } else {
107 bt = tags->bitmap_tags;
108 tag_offset = tags->nr_reserved_tags;
109 }
110
111 tag = __blk_mq_get_tag(data, bt);
112 if (tag != BLK_MQ_NO_TAG)
113 goto found_tag;
114
115 if (data->flags & BLK_MQ_REQ_NOWAIT)
116 return BLK_MQ_NO_TAG;
117
118 ws = bt_wait_ptr(bt, data->hctx);
119 do {
120 struct sbitmap_queue *bt_prev;
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127 blk_mq_run_hw_queue(data->hctx, false);
128
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132
133 tag = __blk_mq_get_tag(data, bt);
134 if (tag != BLK_MQ_NO_TAG)
135 break;
136
137 sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
138
139 tag = __blk_mq_get_tag(data, bt);
140 if (tag != BLK_MQ_NO_TAG)
141 break;
142
143 bt_prev = bt;
144 io_schedule();
145
146 sbitmap_finish_wait(bt, ws, &wait);
147
148 data->ctx = blk_mq_get_ctx(data->q);
149 data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
150 data->ctx);
151 tags = blk_mq_tags_from_data(data);
152 if (data->flags & BLK_MQ_REQ_RESERVED)
153 bt = tags->breserved_tags;
154 else
155 bt = tags->bitmap_tags;
156
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161
162 if (bt != bt_prev)
163 sbitmap_queue_wake_up(bt_prev);
164
165 ws = bt_wait_ptr(bt, data->hctx);
166 } while (1);
167
168 sbitmap_finish_wait(bt, ws, &wait);
169
170found_tag:
171
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174
175 if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
176 blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
177 return BLK_MQ_NO_TAG;
178 }
179 return tag + tag_offset;
180}
181
182void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
183 unsigned int tag)
184{
185 if (!blk_mq_tag_is_reserved(tags, tag)) {
186 const int real_tag = tag - tags->nr_reserved_tags;
187
188 BUG_ON(real_tag >= tags->nr_tags);
189 sbitmap_queue_clear(tags->bitmap_tags, real_tag, ctx->cpu);
190 } else {
191 BUG_ON(tag >= tags->nr_reserved_tags);
192 sbitmap_queue_clear(tags->breserved_tags, tag, ctx->cpu);
193 }
194}
195
196struct bt_iter_data {
197 struct blk_mq_hw_ctx *hctx;
198 busy_iter_fn *fn;
199 void *data;
200 bool reserved;
201};
202
203static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
204 unsigned int bitnr)
205{
206 struct request *rq;
207 unsigned long flags;
208
209 spin_lock_irqsave(&tags->lock, flags);
210 rq = tags->rqs[bitnr];
211 if (!rq || rq->tag != bitnr || !refcount_inc_not_zero(&rq->ref))
212 rq = NULL;
213 spin_unlock_irqrestore(&tags->lock, flags);
214 return rq;
215}
216
217static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
218{
219 struct bt_iter_data *iter_data = data;
220 struct blk_mq_hw_ctx *hctx = iter_data->hctx;
221 struct blk_mq_tags *tags = hctx->tags;
222 bool reserved = iter_data->reserved;
223 struct request *rq;
224 bool ret = true;
225
226 if (!reserved)
227 bitnr += tags->nr_reserved_tags;
228
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231
232 rq = blk_mq_find_and_get_req(tags, bitnr);
233 if (!rq)
234 return true;
235
236 if (rq->q == hctx->queue && rq->mq_hctx == hctx)
237 ret = iter_data->fn(hctx, rq, iter_data->data, reserved);
238 blk_mq_put_rq_ref(rq);
239 return ret;
240}
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255
256static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
257 busy_iter_fn *fn, void *data, bool reserved)
258{
259 struct bt_iter_data iter_data = {
260 .hctx = hctx,
261 .fn = fn,
262 .data = data,
263 .reserved = reserved,
264 };
265
266 sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
267}
268
269struct bt_tags_iter_data {
270 struct blk_mq_tags *tags;
271 busy_tag_iter_fn *fn;
272 void *data;
273 unsigned int flags;
274};
275
276#define BT_TAG_ITER_RESERVED (1 << 0)
277#define BT_TAG_ITER_STARTED (1 << 1)
278#define BT_TAG_ITER_STATIC_RQS (1 << 2)
279
280static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
281{
282 struct bt_tags_iter_data *iter_data = data;
283 struct blk_mq_tags *tags = iter_data->tags;
284 bool reserved = iter_data->flags & BT_TAG_ITER_RESERVED;
285 struct request *rq;
286 bool ret = true;
287 bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS);
288
289 if (!reserved)
290 bitnr += tags->nr_reserved_tags;
291
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295
296 if (iter_static_rqs)
297 rq = tags->static_rqs[bitnr];
298 else
299 rq = blk_mq_find_and_get_req(tags, bitnr);
300 if (!rq)
301 return true;
302
303 if (!(iter_data->flags & BT_TAG_ITER_STARTED) ||
304 blk_mq_request_started(rq))
305 ret = iter_data->fn(rq, iter_data->data, reserved);
306 if (!iter_static_rqs)
307 blk_mq_put_rq_ref(rq);
308 return ret;
309}
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323static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
324 busy_tag_iter_fn *fn, void *data, unsigned int flags)
325{
326 struct bt_tags_iter_data iter_data = {
327 .tags = tags,
328 .fn = fn,
329 .data = data,
330 .flags = flags,
331 };
332
333 if (tags->rqs)
334 sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
335}
336
337static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags,
338 busy_tag_iter_fn *fn, void *priv, unsigned int flags)
339{
340 WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED);
341
342 if (tags->nr_reserved_tags)
343 bt_tags_for_each(tags, tags->breserved_tags, fn, priv,
344 flags | BT_TAG_ITER_RESERVED);
345 bt_tags_for_each(tags, tags->bitmap_tags, fn, priv, flags);
346}
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360void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
361 void *priv)
362{
363 __blk_mq_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS);
364}
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378
379void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
380 busy_tag_iter_fn *fn, void *priv)
381{
382 int i;
383
384 for (i = 0; i < tagset->nr_hw_queues; i++) {
385 if (tagset->tags && tagset->tags[i])
386 __blk_mq_all_tag_iter(tagset->tags[i], fn, priv,
387 BT_TAG_ITER_STARTED);
388 }
389}
390EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
391
392static bool blk_mq_tagset_count_completed_rqs(struct request *rq,
393 void *data, bool reserved)
394{
395 unsigned *count = data;
396
397 if (blk_mq_request_completed(rq))
398 (*count)++;
399 return true;
400}
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408
409void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset)
410{
411 while (true) {
412 unsigned count = 0;
413
414 blk_mq_tagset_busy_iter(tagset,
415 blk_mq_tagset_count_completed_rqs, &count);
416 if (!count)
417 break;
418 msleep(5);
419 }
420}
421EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
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436
437void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
438 void *priv)
439{
440 struct blk_mq_hw_ctx *hctx;
441 int i;
442
443
444
445
446
447
448 if (!percpu_ref_tryget(&q->q_usage_counter))
449 return;
450
451 queue_for_each_hw_ctx(q, hctx, i) {
452 struct blk_mq_tags *tags = hctx->tags;
453
454
455
456
457
458 if (!blk_mq_hw_queue_mapped(hctx))
459 continue;
460
461 if (tags->nr_reserved_tags)
462 bt_for_each(hctx, tags->breserved_tags, fn, priv, true);
463 bt_for_each(hctx, tags->bitmap_tags, fn, priv, false);
464 }
465 blk_queue_exit(q);
466}
467
468static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
469 bool round_robin, int node)
470{
471 return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
472 node);
473}
474
475int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags,
476 struct sbitmap_queue *breserved_tags,
477 unsigned int queue_depth, unsigned int reserved,
478 int node, int alloc_policy)
479{
480 unsigned int depth = queue_depth - reserved;
481 bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
482
483 if (bt_alloc(bitmap_tags, depth, round_robin, node))
484 return -ENOMEM;
485 if (bt_alloc(breserved_tags, reserved, round_robin, node))
486 goto free_bitmap_tags;
487
488 return 0;
489
490free_bitmap_tags:
491 sbitmap_queue_free(bitmap_tags);
492 return -ENOMEM;
493}
494
495static int blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
496 int node, int alloc_policy)
497{
498 int ret;
499
500 ret = blk_mq_init_bitmaps(&tags->__bitmap_tags,
501 &tags->__breserved_tags,
502 tags->nr_tags, tags->nr_reserved_tags,
503 node, alloc_policy);
504 if (ret)
505 return ret;
506
507 tags->bitmap_tags = &tags->__bitmap_tags;
508 tags->breserved_tags = &tags->__breserved_tags;
509
510 return 0;
511}
512
513int blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *set)
514{
515 int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags);
516 int i, ret;
517
518 ret = blk_mq_init_bitmaps(&set->__bitmap_tags, &set->__breserved_tags,
519 set->queue_depth, set->reserved_tags,
520 set->numa_node, alloc_policy);
521 if (ret)
522 return ret;
523
524 for (i = 0; i < set->nr_hw_queues; i++) {
525 struct blk_mq_tags *tags = set->tags[i];
526
527 tags->bitmap_tags = &set->__bitmap_tags;
528 tags->breserved_tags = &set->__breserved_tags;
529 }
530
531 return 0;
532}
533
534void blk_mq_exit_shared_sbitmap(struct blk_mq_tag_set *set)
535{
536 sbitmap_queue_free(&set->__bitmap_tags);
537 sbitmap_queue_free(&set->__breserved_tags);
538}
539
540struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
541 unsigned int reserved_tags,
542 int node, unsigned int flags)
543{
544 int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(flags);
545 struct blk_mq_tags *tags;
546
547 if (total_tags > BLK_MQ_TAG_MAX) {
548 pr_err("blk-mq: tag depth too large\n");
549 return NULL;
550 }
551
552 tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
553 if (!tags)
554 return NULL;
555
556 tags->nr_tags = total_tags;
557 tags->nr_reserved_tags = reserved_tags;
558 spin_lock_init(&tags->lock);
559
560 if (blk_mq_is_sbitmap_shared(flags))
561 return tags;
562
563 if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
564 kfree(tags);
565 return NULL;
566 }
567 return tags;
568}
569
570void blk_mq_free_tags(struct blk_mq_tags *tags, unsigned int flags)
571{
572 if (!blk_mq_is_sbitmap_shared(flags)) {
573 sbitmap_queue_free(tags->bitmap_tags);
574 sbitmap_queue_free(tags->breserved_tags);
575 }
576 kfree(tags);
577}
578
579int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
580 struct blk_mq_tags **tagsptr, unsigned int tdepth,
581 bool can_grow)
582{
583 struct blk_mq_tags *tags = *tagsptr;
584
585 if (tdepth <= tags->nr_reserved_tags)
586 return -EINVAL;
587
588
589
590
591
592 if (tdepth > tags->nr_tags) {
593 struct blk_mq_tag_set *set = hctx->queue->tag_set;
594 struct blk_mq_tags *new;
595 bool ret;
596
597 if (!can_grow)
598 return -EINVAL;
599
600
601
602
603
604 if (tdepth > MAX_SCHED_RQ)
605 return -EINVAL;
606
607 new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth,
608 tags->nr_reserved_tags, set->flags);
609 if (!new)
610 return -ENOMEM;
611 ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
612 if (ret) {
613 blk_mq_free_rq_map(new, set->flags);
614 return -ENOMEM;
615 }
616
617 blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
618 blk_mq_free_rq_map(*tagsptr, set->flags);
619 *tagsptr = new;
620 } else {
621
622
623
624
625 sbitmap_queue_resize(tags->bitmap_tags,
626 tdepth - tags->nr_reserved_tags);
627 }
628
629 return 0;
630}
631
632void blk_mq_tag_resize_shared_sbitmap(struct blk_mq_tag_set *set, unsigned int size)
633{
634 sbitmap_queue_resize(&set->__bitmap_tags, size - set->reserved_tags);
635}
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649u32 blk_mq_unique_tag(struct request *rq)
650{
651 return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
652 (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
653}
654EXPORT_SYMBOL(blk_mq_unique_tag);
655