Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Tag allocation using scalable bitmaps. Uses active queue tracking to support
4 : * fairer distribution of tags between multiple submitters when a shared tag map
5 : * is used.
6 : *
7 : * Copyright (C) 2013-2014 Jens Axboe
8 : */
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 : /*
20 : * Recalculate wakeup batch when tag is shared by hctx.
21 : */
22 0 : static void blk_mq_update_wake_batch(struct blk_mq_tags *tags,
23 : unsigned int users)
24 : {
25 0 : if (!users)
26 : return;
27 :
28 0 : sbitmap_queue_recalculate_wake_batch(&tags->bitmap_tags,
29 : users);
30 0 : sbitmap_queue_recalculate_wake_batch(&tags->breserved_tags,
31 : users);
32 : }
33 :
34 : /*
35 : * If a previously inactive queue goes active, bump the active user count.
36 : * We need to do this before try to allocate driver tag, then even if fail
37 : * to get tag when first time, the other shared-tag users could reserve
38 : * budget for it.
39 : */
40 0 : void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
41 : {
42 : unsigned int users;
43 :
44 0 : if (blk_mq_is_shared_tags(hctx->flags)) {
45 0 : struct request_queue *q = hctx->queue;
46 :
47 0 : if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
48 : return;
49 0 : set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags);
50 : } else {
51 0 : if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
52 : return;
53 0 : set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state);
54 : }
55 :
56 0 : users = atomic_inc_return(&hctx->tags->active_queues);
57 :
58 0 : blk_mq_update_wake_batch(hctx->tags, users);
59 : }
60 :
61 : /*
62 : * Wakeup all potentially sleeping on tags
63 : */
64 0 : void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
65 : {
66 0 : sbitmap_queue_wake_all(&tags->bitmap_tags);
67 0 : if (include_reserve)
68 0 : sbitmap_queue_wake_all(&tags->breserved_tags);
69 0 : }
70 :
71 : /*
72 : * If a previously busy queue goes inactive, potential waiters could now
73 : * be allowed to queue. Wake them up and check.
74 : */
75 0 : void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
76 : {
77 0 : struct blk_mq_tags *tags = hctx->tags;
78 : unsigned int users;
79 :
80 0 : if (blk_mq_is_shared_tags(hctx->flags)) {
81 0 : struct request_queue *q = hctx->queue;
82 :
83 0 : if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
84 0 : &q->queue_flags))
85 : return;
86 : } else {
87 0 : if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
88 : return;
89 : }
90 :
91 0 : users = atomic_dec_return(&tags->active_queues);
92 :
93 0 : blk_mq_update_wake_batch(tags, users);
94 :
95 : blk_mq_tag_wakeup_all(tags, false);
96 : }
97 :
98 0 : static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
99 : struct sbitmap_queue *bt)
100 : {
101 0 : if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
102 0 : !hctx_may_queue(data->hctx, bt))
103 : return BLK_MQ_NO_TAG;
104 :
105 0 : if (data->shallow_depth)
106 0 : return sbitmap_queue_get_shallow(bt, data->shallow_depth);
107 : else
108 0 : return __sbitmap_queue_get(bt);
109 : }
110 :
111 0 : unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags,
112 : unsigned int *offset)
113 : {
114 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
115 0 : struct sbitmap_queue *bt = &tags->bitmap_tags;
116 : unsigned long ret;
117 :
118 0 : if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED ||
119 0 : data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
120 : return 0;
121 0 : ret = __sbitmap_queue_get_batch(bt, nr_tags, offset);
122 0 : *offset += tags->nr_reserved_tags;
123 0 : return ret;
124 : }
125 :
126 0 : unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
127 : {
128 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
129 : struct sbitmap_queue *bt;
130 : struct sbq_wait_state *ws;
131 0 : DEFINE_SBQ_WAIT(wait);
132 : unsigned int tag_offset;
133 : int tag;
134 :
135 0 : if (data->flags & BLK_MQ_REQ_RESERVED) {
136 0 : if (unlikely(!tags->nr_reserved_tags)) {
137 0 : WARN_ON_ONCE(1);
138 : return BLK_MQ_NO_TAG;
139 : }
140 0 : bt = &tags->breserved_tags;
141 0 : tag_offset = 0;
142 : } else {
143 0 : bt = &tags->bitmap_tags;
144 0 : tag_offset = tags->nr_reserved_tags;
145 : }
146 :
147 0 : tag = __blk_mq_get_tag(data, bt);
148 0 : if (tag != BLK_MQ_NO_TAG)
149 : goto found_tag;
150 :
151 0 : if (data->flags & BLK_MQ_REQ_NOWAIT)
152 : return BLK_MQ_NO_TAG;
153 :
154 0 : ws = bt_wait_ptr(bt, data->hctx);
155 : do {
156 : struct sbitmap_queue *bt_prev;
157 :
158 : /*
159 : * We're out of tags on this hardware queue, kick any
160 : * pending IO submits before going to sleep waiting for
161 : * some to complete.
162 : */
163 0 : blk_mq_run_hw_queue(data->hctx, false);
164 :
165 : /*
166 : * Retry tag allocation after running the hardware queue,
167 : * as running the queue may also have found completions.
168 : */
169 0 : tag = __blk_mq_get_tag(data, bt);
170 0 : if (tag != BLK_MQ_NO_TAG)
171 : break;
172 :
173 0 : sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
174 :
175 0 : tag = __blk_mq_get_tag(data, bt);
176 0 : if (tag != BLK_MQ_NO_TAG)
177 : break;
178 :
179 0 : bt_prev = bt;
180 0 : io_schedule();
181 :
182 0 : sbitmap_finish_wait(bt, ws, &wait);
183 :
184 0 : data->ctx = blk_mq_get_ctx(data->q);
185 0 : data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
186 : data->ctx);
187 0 : tags = blk_mq_tags_from_data(data);
188 0 : if (data->flags & BLK_MQ_REQ_RESERVED)
189 0 : bt = &tags->breserved_tags;
190 : else
191 0 : bt = &tags->bitmap_tags;
192 :
193 : /*
194 : * If destination hw queue is changed, fake wake up on
195 : * previous queue for compensating the wake up miss, so
196 : * other allocations on previous queue won't be starved.
197 : */
198 0 : if (bt != bt_prev)
199 0 : sbitmap_queue_wake_up(bt_prev, 1);
200 :
201 0 : ws = bt_wait_ptr(bt, data->hctx);
202 : } while (1);
203 :
204 0 : sbitmap_finish_wait(bt, ws, &wait);
205 :
206 : found_tag:
207 : /*
208 : * Give up this allocation if the hctx is inactive. The caller will
209 : * retry on an active hctx.
210 : */
211 0 : if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
212 0 : blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
213 0 : return BLK_MQ_NO_TAG;
214 : }
215 0 : return tag + tag_offset;
216 : }
217 :
218 0 : void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
219 : unsigned int tag)
220 : {
221 0 : if (!blk_mq_tag_is_reserved(tags, tag)) {
222 0 : const int real_tag = tag - tags->nr_reserved_tags;
223 :
224 0 : BUG_ON(real_tag >= tags->nr_tags);
225 0 : sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
226 : } else {
227 0 : sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
228 : }
229 0 : }
230 :
231 0 : void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags)
232 : {
233 0 : sbitmap_queue_clear_batch(&tags->bitmap_tags, tags->nr_reserved_tags,
234 : tag_array, nr_tags);
235 0 : }
236 :
237 : struct bt_iter_data {
238 : struct blk_mq_hw_ctx *hctx;
239 : struct request_queue *q;
240 : busy_tag_iter_fn *fn;
241 : void *data;
242 : bool reserved;
243 : };
244 :
245 0 : static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
246 : unsigned int bitnr)
247 : {
248 : struct request *rq;
249 : unsigned long flags;
250 :
251 0 : spin_lock_irqsave(&tags->lock, flags);
252 0 : rq = tags->rqs[bitnr];
253 0 : if (!rq || rq->tag != bitnr || !req_ref_inc_not_zero(rq))
254 : rq = NULL;
255 0 : spin_unlock_irqrestore(&tags->lock, flags);
256 0 : return rq;
257 : }
258 :
259 0 : static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
260 : {
261 0 : struct bt_iter_data *iter_data = data;
262 0 : struct blk_mq_hw_ctx *hctx = iter_data->hctx;
263 0 : struct request_queue *q = iter_data->q;
264 0 : struct blk_mq_tag_set *set = q->tag_set;
265 : struct blk_mq_tags *tags;
266 : struct request *rq;
267 0 : bool ret = true;
268 :
269 0 : if (blk_mq_is_shared_tags(set->flags))
270 0 : tags = set->shared_tags;
271 : else
272 0 : tags = hctx->tags;
273 :
274 0 : if (!iter_data->reserved)
275 0 : bitnr += tags->nr_reserved_tags;
276 : /*
277 : * We can hit rq == NULL here, because the tagging functions
278 : * test and set the bit before assigning ->rqs[].
279 : */
280 0 : rq = blk_mq_find_and_get_req(tags, bitnr);
281 0 : if (!rq)
282 : return true;
283 :
284 0 : if (rq->q == q && (!hctx || rq->mq_hctx == hctx))
285 0 : ret = iter_data->fn(rq, iter_data->data);
286 0 : blk_mq_put_rq_ref(rq);
287 0 : return ret;
288 : }
289 :
290 : /**
291 : * bt_for_each - iterate over the requests associated with a hardware queue
292 : * @hctx: Hardware queue to examine.
293 : * @q: Request queue to examine.
294 : * @bt: sbitmap to examine. This is either the breserved_tags member
295 : * or the bitmap_tags member of struct blk_mq_tags.
296 : * @fn: Pointer to the function that will be called for each request
297 : * associated with @hctx that has been assigned a driver tag.
298 : * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
299 : * where rq is a pointer to a request. Return true to continue
300 : * iterating tags, false to stop.
301 : * @data: Will be passed as third argument to @fn.
302 : * @reserved: Indicates whether @bt is the breserved_tags member or the
303 : * bitmap_tags member of struct blk_mq_tags.
304 : */
305 : static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct request_queue *q,
306 : struct sbitmap_queue *bt, busy_tag_iter_fn *fn,
307 : void *data, bool reserved)
308 : {
309 0 : struct bt_iter_data iter_data = {
310 : .hctx = hctx,
311 : .fn = fn,
312 : .data = data,
313 : .reserved = reserved,
314 : .q = q,
315 : };
316 :
317 0 : sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
318 : }
319 :
320 : struct bt_tags_iter_data {
321 : struct blk_mq_tags *tags;
322 : busy_tag_iter_fn *fn;
323 : void *data;
324 : unsigned int flags;
325 : };
326 :
327 : #define BT_TAG_ITER_RESERVED (1 << 0)
328 : #define BT_TAG_ITER_STARTED (1 << 1)
329 : #define BT_TAG_ITER_STATIC_RQS (1 << 2)
330 :
331 0 : static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
332 : {
333 0 : struct bt_tags_iter_data *iter_data = data;
334 0 : struct blk_mq_tags *tags = iter_data->tags;
335 : struct request *rq;
336 0 : bool ret = true;
337 0 : bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS);
338 :
339 0 : if (!(iter_data->flags & BT_TAG_ITER_RESERVED))
340 0 : bitnr += tags->nr_reserved_tags;
341 :
342 : /*
343 : * We can hit rq == NULL here, because the tagging functions
344 : * test and set the bit before assigning ->rqs[].
345 : */
346 0 : if (iter_static_rqs)
347 0 : rq = tags->static_rqs[bitnr];
348 : else
349 0 : rq = blk_mq_find_and_get_req(tags, bitnr);
350 0 : if (!rq)
351 : return true;
352 :
353 0 : if (!(iter_data->flags & BT_TAG_ITER_STARTED) ||
354 0 : blk_mq_request_started(rq))
355 0 : ret = iter_data->fn(rq, iter_data->data);
356 0 : if (!iter_static_rqs)
357 0 : blk_mq_put_rq_ref(rq);
358 : return ret;
359 : }
360 :
361 : /**
362 : * bt_tags_for_each - iterate over the requests in a tag map
363 : * @tags: Tag map to iterate over.
364 : * @bt: sbitmap to examine. This is either the breserved_tags member
365 : * or the bitmap_tags member of struct blk_mq_tags.
366 : * @fn: Pointer to the function that will be called for each started
367 : * request. @fn will be called as follows: @fn(rq, @data,
368 : * @reserved) where rq is a pointer to a request. Return true
369 : * to continue iterating tags, false to stop.
370 : * @data: Will be passed as second argument to @fn.
371 : * @flags: BT_TAG_ITER_*
372 : */
373 : static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
374 : busy_tag_iter_fn *fn, void *data, unsigned int flags)
375 : {
376 0 : struct bt_tags_iter_data iter_data = {
377 : .tags = tags,
378 : .fn = fn,
379 : .data = data,
380 : .flags = flags,
381 : };
382 :
383 0 : if (tags->rqs)
384 0 : sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
385 : }
386 :
387 0 : static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags,
388 : busy_tag_iter_fn *fn, void *priv, unsigned int flags)
389 : {
390 0 : WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED);
391 :
392 0 : if (tags->nr_reserved_tags)
393 0 : bt_tags_for_each(tags, &tags->breserved_tags, fn, priv,
394 : flags | BT_TAG_ITER_RESERVED);
395 0 : bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, flags);
396 0 : }
397 :
398 : /**
399 : * blk_mq_all_tag_iter - iterate over all requests in a tag map
400 : * @tags: Tag map to iterate over.
401 : * @fn: Pointer to the function that will be called for each
402 : * request. @fn will be called as follows: @fn(rq, @priv,
403 : * reserved) where rq is a pointer to a request. 'reserved'
404 : * indicates whether or not @rq is a reserved request. Return
405 : * true to continue iterating tags, false to stop.
406 : * @priv: Will be passed as second argument to @fn.
407 : *
408 : * Caller has to pass the tag map from which requests are allocated.
409 : */
410 0 : void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
411 : void *priv)
412 : {
413 0 : __blk_mq_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS);
414 0 : }
415 :
416 : /**
417 : * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set
418 : * @tagset: Tag set to iterate over.
419 : * @fn: Pointer to the function that will be called for each started
420 : * request. @fn will be called as follows: @fn(rq, @priv,
421 : * reserved) where rq is a pointer to a request. 'reserved'
422 : * indicates whether or not @rq is a reserved request. Return
423 : * true to continue iterating tags, false to stop.
424 : * @priv: Will be passed as second argument to @fn.
425 : *
426 : * We grab one request reference before calling @fn and release it after
427 : * @fn returns.
428 : */
429 0 : void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
430 : busy_tag_iter_fn *fn, void *priv)
431 : {
432 0 : unsigned int flags = tagset->flags;
433 : int i, nr_tags;
434 :
435 0 : nr_tags = blk_mq_is_shared_tags(flags) ? 1 : tagset->nr_hw_queues;
436 :
437 0 : for (i = 0; i < nr_tags; i++) {
438 0 : if (tagset->tags && tagset->tags[i])
439 0 : __blk_mq_all_tag_iter(tagset->tags[i], fn, priv,
440 : BT_TAG_ITER_STARTED);
441 : }
442 0 : }
443 : EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
444 :
445 0 : static bool blk_mq_tagset_count_completed_rqs(struct request *rq, void *data)
446 : {
447 0 : unsigned *count = data;
448 :
449 0 : if (blk_mq_request_completed(rq))
450 0 : (*count)++;
451 0 : return true;
452 : }
453 :
454 : /**
455 : * blk_mq_tagset_wait_completed_request - Wait until all scheduled request
456 : * completions have finished.
457 : * @tagset: Tag set to drain completed request
458 : *
459 : * Note: This function has to be run after all IO queues are shutdown
460 : */
461 0 : void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset)
462 : {
463 0 : while (true) {
464 0 : unsigned count = 0;
465 :
466 0 : blk_mq_tagset_busy_iter(tagset,
467 : blk_mq_tagset_count_completed_rqs, &count);
468 0 : if (!count)
469 : break;
470 0 : msleep(5);
471 : }
472 0 : }
473 : EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
474 :
475 : /**
476 : * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag
477 : * @q: Request queue to examine.
478 : * @fn: Pointer to the function that will be called for each request
479 : * on @q. @fn will be called as follows: @fn(hctx, rq, @priv,
480 : * reserved) where rq is a pointer to a request and hctx points
481 : * to the hardware queue associated with the request. 'reserved'
482 : * indicates whether or not @rq is a reserved request.
483 : * @priv: Will be passed as third argument to @fn.
484 : *
485 : * Note: if @q->tag_set is shared with other request queues then @fn will be
486 : * called for all requests on all queues that share that tag set and not only
487 : * for requests associated with @q.
488 : */
489 0 : void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn,
490 : void *priv)
491 : {
492 : /*
493 : * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and hctx_table
494 : * while the queue is frozen. So we can use q_usage_counter to avoid
495 : * racing with it.
496 : */
497 0 : if (!percpu_ref_tryget(&q->q_usage_counter))
498 : return;
499 :
500 0 : if (blk_mq_is_shared_tags(q->tag_set->flags)) {
501 0 : struct blk_mq_tags *tags = q->tag_set->shared_tags;
502 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
503 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
504 :
505 0 : if (tags->nr_reserved_tags)
506 : bt_for_each(NULL, q, bresv, fn, priv, true);
507 : bt_for_each(NULL, q, btags, fn, priv, false);
508 : } else {
509 : struct blk_mq_hw_ctx *hctx;
510 : unsigned long i;
511 :
512 0 : queue_for_each_hw_ctx(q, hctx, i) {
513 0 : struct blk_mq_tags *tags = hctx->tags;
514 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
515 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
516 :
517 : /*
518 : * If no software queues are currently mapped to this
519 : * hardware queue, there's nothing to check
520 : */
521 0 : if (!blk_mq_hw_queue_mapped(hctx))
522 0 : continue;
523 :
524 0 : if (tags->nr_reserved_tags)
525 : bt_for_each(hctx, q, bresv, fn, priv, true);
526 : bt_for_each(hctx, q, btags, fn, priv, false);
527 : }
528 : }
529 0 : blk_queue_exit(q);
530 : }
531 :
532 : static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
533 : bool round_robin, int node)
534 : {
535 0 : return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
536 : node);
537 : }
538 :
539 0 : int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags,
540 : struct sbitmap_queue *breserved_tags,
541 : unsigned int queue_depth, unsigned int reserved,
542 : int node, int alloc_policy)
543 : {
544 0 : unsigned int depth = queue_depth - reserved;
545 0 : bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
546 :
547 0 : if (bt_alloc(bitmap_tags, depth, round_robin, node))
548 : return -ENOMEM;
549 0 : if (bt_alloc(breserved_tags, reserved, round_robin, node))
550 : goto free_bitmap_tags;
551 :
552 : return 0;
553 :
554 : free_bitmap_tags:
555 0 : sbitmap_queue_free(bitmap_tags);
556 0 : return -ENOMEM;
557 : }
558 :
559 0 : struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
560 : unsigned int reserved_tags,
561 : int node, int alloc_policy)
562 : {
563 : struct blk_mq_tags *tags;
564 :
565 0 : if (total_tags > BLK_MQ_TAG_MAX) {
566 0 : pr_err("blk-mq: tag depth too large\n");
567 0 : return NULL;
568 : }
569 :
570 0 : tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
571 0 : if (!tags)
572 : return NULL;
573 :
574 0 : tags->nr_tags = total_tags;
575 0 : tags->nr_reserved_tags = reserved_tags;
576 0 : spin_lock_init(&tags->lock);
577 :
578 0 : if (blk_mq_init_bitmaps(&tags->bitmap_tags, &tags->breserved_tags,
579 : total_tags, reserved_tags, node,
580 : alloc_policy) < 0) {
581 0 : kfree(tags);
582 0 : return NULL;
583 : }
584 : return tags;
585 : }
586 :
587 0 : void blk_mq_free_tags(struct blk_mq_tags *tags)
588 : {
589 0 : sbitmap_queue_free(&tags->bitmap_tags);
590 0 : sbitmap_queue_free(&tags->breserved_tags);
591 0 : kfree(tags);
592 0 : }
593 :
594 0 : int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
595 : struct blk_mq_tags **tagsptr, unsigned int tdepth,
596 : bool can_grow)
597 : {
598 0 : struct blk_mq_tags *tags = *tagsptr;
599 :
600 0 : if (tdepth <= tags->nr_reserved_tags)
601 : return -EINVAL;
602 :
603 : /*
604 : * If we are allowed to grow beyond the original size, allocate
605 : * a new set of tags before freeing the old one.
606 : */
607 0 : if (tdepth > tags->nr_tags) {
608 0 : struct blk_mq_tag_set *set = hctx->queue->tag_set;
609 : struct blk_mq_tags *new;
610 :
611 0 : if (!can_grow)
612 : return -EINVAL;
613 :
614 : /*
615 : * We need some sort of upper limit, set it high enough that
616 : * no valid use cases should require more.
617 : */
618 0 : if (tdepth > MAX_SCHED_RQ)
619 : return -EINVAL;
620 :
621 : /*
622 : * Only the sbitmap needs resizing since we allocated the max
623 : * initially.
624 : */
625 0 : if (blk_mq_is_shared_tags(set->flags))
626 : return 0;
627 :
628 0 : new = blk_mq_alloc_map_and_rqs(set, hctx->queue_num, tdepth);
629 0 : if (!new)
630 : return -ENOMEM;
631 :
632 0 : blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num);
633 0 : *tagsptr = new;
634 : } else {
635 : /*
636 : * Don't need (or can't) update reserved tags here, they
637 : * remain static and should never need resizing.
638 : */
639 0 : sbitmap_queue_resize(&tags->bitmap_tags,
640 : tdepth - tags->nr_reserved_tags);
641 : }
642 :
643 : return 0;
644 : }
645 :
646 0 : void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size)
647 : {
648 0 : struct blk_mq_tags *tags = set->shared_tags;
649 :
650 0 : sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags);
651 0 : }
652 :
653 0 : void blk_mq_tag_update_sched_shared_tags(struct request_queue *q)
654 : {
655 0 : sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags,
656 0 : q->nr_requests - q->tag_set->reserved_tags);
657 0 : }
658 :
659 : /**
660 : * blk_mq_unique_tag() - return a tag that is unique queue-wide
661 : * @rq: request for which to compute a unique tag
662 : *
663 : * The tag field in struct request is unique per hardware queue but not over
664 : * all hardware queues. Hence this function that returns a tag with the
665 : * hardware context index in the upper bits and the per hardware queue tag in
666 : * the lower bits.
667 : *
668 : * Note: When called for a request that is queued on a non-multiqueue request
669 : * queue, the hardware context index is set to zero.
670 : */
671 0 : u32 blk_mq_unique_tag(struct request *rq)
672 : {
673 0 : return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
674 0 : (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
675 : }
676 : EXPORT_SYMBOL(blk_mq_unique_tag);
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