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 : bool __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 0 : test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags)) {
49 : return true;
50 : }
51 : } else {
52 0 : if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) ||
53 0 : test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) {
54 : return true;
55 : }
56 : }
57 :
58 0 : users = atomic_inc_return(&hctx->tags->active_queues);
59 :
60 0 : blk_mq_update_wake_batch(hctx->tags, users);
61 :
62 0 : return true;
63 : }
64 :
65 : /*
66 : * Wakeup all potentially sleeping on tags
67 : */
68 0 : void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
69 : {
70 0 : sbitmap_queue_wake_all(&tags->bitmap_tags);
71 0 : if (include_reserve)
72 0 : sbitmap_queue_wake_all(&tags->breserved_tags);
73 0 : }
74 :
75 : /*
76 : * If a previously busy queue goes inactive, potential waiters could now
77 : * be allowed to queue. Wake them up and check.
78 : */
79 0 : void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
80 : {
81 0 : struct blk_mq_tags *tags = hctx->tags;
82 : unsigned int users;
83 :
84 0 : if (blk_mq_is_shared_tags(hctx->flags)) {
85 0 : struct request_queue *q = hctx->queue;
86 :
87 0 : if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
88 0 : &q->queue_flags))
89 : return;
90 : } else {
91 0 : if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
92 : return;
93 : }
94 :
95 0 : users = atomic_dec_return(&tags->active_queues);
96 :
97 0 : blk_mq_update_wake_batch(tags, users);
98 :
99 : blk_mq_tag_wakeup_all(tags, false);
100 : }
101 :
102 0 : static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
103 : struct sbitmap_queue *bt)
104 : {
105 0 : if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
106 0 : !hctx_may_queue(data->hctx, bt))
107 : return BLK_MQ_NO_TAG;
108 :
109 0 : if (data->shallow_depth)
110 0 : return sbitmap_queue_get_shallow(bt, data->shallow_depth);
111 : else
112 0 : return __sbitmap_queue_get(bt);
113 : }
114 :
115 0 : unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags,
116 : unsigned int *offset)
117 : {
118 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
119 0 : struct sbitmap_queue *bt = &tags->bitmap_tags;
120 : unsigned long ret;
121 :
122 0 : if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED ||
123 0 : data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
124 : return 0;
125 0 : ret = __sbitmap_queue_get_batch(bt, nr_tags, offset);
126 0 : *offset += tags->nr_reserved_tags;
127 0 : return ret;
128 : }
129 :
130 0 : unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
131 : {
132 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
133 : struct sbitmap_queue *bt;
134 : struct sbq_wait_state *ws;
135 0 : DEFINE_SBQ_WAIT(wait);
136 : unsigned int tag_offset;
137 : int tag;
138 :
139 0 : if (data->flags & BLK_MQ_REQ_RESERVED) {
140 0 : if (unlikely(!tags->nr_reserved_tags)) {
141 0 : WARN_ON_ONCE(1);
142 : return BLK_MQ_NO_TAG;
143 : }
144 0 : bt = &tags->breserved_tags;
145 0 : tag_offset = 0;
146 : } else {
147 0 : bt = &tags->bitmap_tags;
148 0 : tag_offset = tags->nr_reserved_tags;
149 : }
150 :
151 0 : tag = __blk_mq_get_tag(data, bt);
152 0 : if (tag != BLK_MQ_NO_TAG)
153 : goto found_tag;
154 :
155 0 : if (data->flags & BLK_MQ_REQ_NOWAIT)
156 : return BLK_MQ_NO_TAG;
157 :
158 0 : ws = bt_wait_ptr(bt, data->hctx);
159 : do {
160 : struct sbitmap_queue *bt_prev;
161 :
162 : /*
163 : * We're out of tags on this hardware queue, kick any
164 : * pending IO submits before going to sleep waiting for
165 : * some to complete.
166 : */
167 0 : blk_mq_run_hw_queue(data->hctx, false);
168 :
169 : /*
170 : * Retry tag allocation after running the hardware queue,
171 : * as running the queue may also have found completions.
172 : */
173 0 : tag = __blk_mq_get_tag(data, bt);
174 0 : if (tag != BLK_MQ_NO_TAG)
175 : break;
176 :
177 0 : sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
178 :
179 0 : tag = __blk_mq_get_tag(data, bt);
180 0 : if (tag != BLK_MQ_NO_TAG)
181 : break;
182 :
183 0 : bt_prev = bt;
184 0 : io_schedule();
185 :
186 0 : sbitmap_finish_wait(bt, ws, &wait);
187 :
188 0 : data->ctx = blk_mq_get_ctx(data->q);
189 0 : data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
190 : data->ctx);
191 0 : tags = blk_mq_tags_from_data(data);
192 0 : if (data->flags & BLK_MQ_REQ_RESERVED)
193 0 : bt = &tags->breserved_tags;
194 : else
195 0 : bt = &tags->bitmap_tags;
196 :
197 : /*
198 : * If destination hw queue is changed, fake wake up on
199 : * previous queue for compensating the wake up miss, so
200 : * other allocations on previous queue won't be starved.
201 : */
202 0 : if (bt != bt_prev)
203 0 : sbitmap_queue_wake_up(bt_prev);
204 :
205 0 : ws = bt_wait_ptr(bt, data->hctx);
206 : } while (1);
207 :
208 0 : sbitmap_finish_wait(bt, ws, &wait);
209 :
210 : found_tag:
211 : /*
212 : * Give up this allocation if the hctx is inactive. The caller will
213 : * retry on an active hctx.
214 : */
215 0 : if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
216 0 : blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
217 0 : return BLK_MQ_NO_TAG;
218 : }
219 0 : return tag + tag_offset;
220 : }
221 :
222 0 : void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
223 : unsigned int tag)
224 : {
225 0 : if (!blk_mq_tag_is_reserved(tags, tag)) {
226 0 : const int real_tag = tag - tags->nr_reserved_tags;
227 :
228 0 : BUG_ON(real_tag >= tags->nr_tags);
229 0 : sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
230 : } else {
231 : BUG_ON(tag >= tags->nr_reserved_tags);
232 0 : sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
233 : }
234 0 : }
235 :
236 0 : void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags)
237 : {
238 0 : sbitmap_queue_clear_batch(&tags->bitmap_tags, tags->nr_reserved_tags,
239 : tag_array, nr_tags);
240 0 : }
241 :
242 : struct bt_iter_data {
243 : struct blk_mq_hw_ctx *hctx;
244 : struct request_queue *q;
245 : busy_tag_iter_fn *fn;
246 : void *data;
247 : bool reserved;
248 : };
249 :
250 0 : static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
251 : unsigned int bitnr)
252 : {
253 : struct request *rq;
254 : unsigned long flags;
255 :
256 0 : spin_lock_irqsave(&tags->lock, flags);
257 0 : rq = tags->rqs[bitnr];
258 0 : if (!rq || rq->tag != bitnr || !req_ref_inc_not_zero(rq))
259 : rq = NULL;
260 0 : spin_unlock_irqrestore(&tags->lock, flags);
261 0 : return rq;
262 : }
263 :
264 0 : static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
265 : {
266 0 : struct bt_iter_data *iter_data = data;
267 0 : struct blk_mq_hw_ctx *hctx = iter_data->hctx;
268 0 : struct request_queue *q = iter_data->q;
269 0 : struct blk_mq_tag_set *set = q->tag_set;
270 0 : bool reserved = iter_data->reserved;
271 : struct blk_mq_tags *tags;
272 : struct request *rq;
273 0 : bool ret = true;
274 :
275 0 : if (blk_mq_is_shared_tags(set->flags))
276 0 : tags = set->shared_tags;
277 : else
278 0 : tags = hctx->tags;
279 :
280 0 : if (!reserved)
281 0 : bitnr += tags->nr_reserved_tags;
282 : /*
283 : * We can hit rq == NULL here, because the tagging functions
284 : * test and set the bit before assigning ->rqs[].
285 : */
286 0 : rq = blk_mq_find_and_get_req(tags, bitnr);
287 0 : if (!rq)
288 : return true;
289 :
290 0 : if (rq->q == q && (!hctx || rq->mq_hctx == hctx))
291 0 : ret = iter_data->fn(rq, iter_data->data, reserved);
292 0 : blk_mq_put_rq_ref(rq);
293 0 : return ret;
294 : }
295 :
296 : /**
297 : * bt_for_each - iterate over the requests associated with a hardware queue
298 : * @hctx: Hardware queue to examine.
299 : * @q: Request queue to examine.
300 : * @bt: sbitmap to examine. This is either the breserved_tags member
301 : * or the bitmap_tags member of struct blk_mq_tags.
302 : * @fn: Pointer to the function that will be called for each request
303 : * associated with @hctx that has been assigned a driver tag.
304 : * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
305 : * where rq is a pointer to a request. Return true to continue
306 : * iterating tags, false to stop.
307 : * @data: Will be passed as third argument to @fn.
308 : * @reserved: Indicates whether @bt is the breserved_tags member or the
309 : * bitmap_tags member of struct blk_mq_tags.
310 : */
311 : static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct request_queue *q,
312 : struct sbitmap_queue *bt, busy_tag_iter_fn *fn,
313 : void *data, bool reserved)
314 : {
315 0 : struct bt_iter_data iter_data = {
316 : .hctx = hctx,
317 : .fn = fn,
318 : .data = data,
319 : .reserved = reserved,
320 : .q = q,
321 : };
322 :
323 0 : sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
324 : }
325 :
326 : struct bt_tags_iter_data {
327 : struct blk_mq_tags *tags;
328 : busy_tag_iter_fn *fn;
329 : void *data;
330 : unsigned int flags;
331 : };
332 :
333 : #define BT_TAG_ITER_RESERVED (1 << 0)
334 : #define BT_TAG_ITER_STARTED (1 << 1)
335 : #define BT_TAG_ITER_STATIC_RQS (1 << 2)
336 :
337 0 : static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
338 : {
339 0 : struct bt_tags_iter_data *iter_data = data;
340 0 : struct blk_mq_tags *tags = iter_data->tags;
341 0 : bool reserved = iter_data->flags & BT_TAG_ITER_RESERVED;
342 : struct request *rq;
343 0 : bool ret = true;
344 0 : bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS);
345 :
346 0 : if (!reserved)
347 0 : bitnr += tags->nr_reserved_tags;
348 :
349 : /*
350 : * We can hit rq == NULL here, because the tagging functions
351 : * test and set the bit before assigning ->rqs[].
352 : */
353 0 : if (iter_static_rqs)
354 0 : rq = tags->static_rqs[bitnr];
355 : else
356 0 : rq = blk_mq_find_and_get_req(tags, bitnr);
357 0 : if (!rq)
358 : return true;
359 :
360 0 : if (!(iter_data->flags & BT_TAG_ITER_STARTED) ||
361 0 : blk_mq_request_started(rq))
362 0 : ret = iter_data->fn(rq, iter_data->data, reserved);
363 0 : if (!iter_static_rqs)
364 0 : blk_mq_put_rq_ref(rq);
365 : return ret;
366 : }
367 :
368 : /**
369 : * bt_tags_for_each - iterate over the requests in a tag map
370 : * @tags: Tag map to iterate over.
371 : * @bt: sbitmap to examine. This is either the breserved_tags member
372 : * or the bitmap_tags member of struct blk_mq_tags.
373 : * @fn: Pointer to the function that will be called for each started
374 : * request. @fn will be called as follows: @fn(rq, @data,
375 : * @reserved) where rq is a pointer to a request. Return true
376 : * to continue iterating tags, false to stop.
377 : * @data: Will be passed as second argument to @fn.
378 : * @flags: BT_TAG_ITER_*
379 : */
380 : static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
381 : busy_tag_iter_fn *fn, void *data, unsigned int flags)
382 : {
383 0 : struct bt_tags_iter_data iter_data = {
384 : .tags = tags,
385 : .fn = fn,
386 : .data = data,
387 : .flags = flags,
388 : };
389 :
390 0 : if (tags->rqs)
391 0 : sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
392 : }
393 :
394 0 : static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags,
395 : busy_tag_iter_fn *fn, void *priv, unsigned int flags)
396 : {
397 0 : WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED);
398 :
399 0 : if (tags->nr_reserved_tags)
400 0 : bt_tags_for_each(tags, &tags->breserved_tags, fn, priv,
401 : flags | BT_TAG_ITER_RESERVED);
402 0 : bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, flags);
403 0 : }
404 :
405 : /**
406 : * blk_mq_all_tag_iter - iterate over all requests in a tag map
407 : * @tags: Tag map to iterate over.
408 : * @fn: Pointer to the function that will be called for each
409 : * request. @fn will be called as follows: @fn(rq, @priv,
410 : * reserved) where rq is a pointer to a request. 'reserved'
411 : * indicates whether or not @rq is a reserved request. Return
412 : * true to continue iterating tags, false to stop.
413 : * @priv: Will be passed as second argument to @fn.
414 : *
415 : * Caller has to pass the tag map from which requests are allocated.
416 : */
417 0 : void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
418 : void *priv)
419 : {
420 0 : __blk_mq_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS);
421 0 : }
422 :
423 : /**
424 : * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set
425 : * @tagset: Tag set to iterate over.
426 : * @fn: Pointer to the function that will be called for each started
427 : * request. @fn will be called as follows: @fn(rq, @priv,
428 : * reserved) where rq is a pointer to a request. 'reserved'
429 : * indicates whether or not @rq is a reserved request. Return
430 : * true to continue iterating tags, false to stop.
431 : * @priv: Will be passed as second argument to @fn.
432 : *
433 : * We grab one request reference before calling @fn and release it after
434 : * @fn returns.
435 : */
436 0 : void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
437 : busy_tag_iter_fn *fn, void *priv)
438 : {
439 0 : unsigned int flags = tagset->flags;
440 : int i, nr_tags;
441 :
442 0 : nr_tags = blk_mq_is_shared_tags(flags) ? 1 : tagset->nr_hw_queues;
443 :
444 0 : for (i = 0; i < nr_tags; i++) {
445 0 : if (tagset->tags && tagset->tags[i])
446 0 : __blk_mq_all_tag_iter(tagset->tags[i], fn, priv,
447 : BT_TAG_ITER_STARTED);
448 : }
449 0 : }
450 : EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
451 :
452 0 : static bool blk_mq_tagset_count_completed_rqs(struct request *rq,
453 : void *data, bool reserved)
454 : {
455 0 : unsigned *count = data;
456 :
457 0 : if (blk_mq_request_completed(rq))
458 0 : (*count)++;
459 0 : return true;
460 : }
461 :
462 : /**
463 : * blk_mq_tagset_wait_completed_request - Wait until all scheduled request
464 : * completions have finished.
465 : * @tagset: Tag set to drain completed request
466 : *
467 : * Note: This function has to be run after all IO queues are shutdown
468 : */
469 0 : void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset)
470 : {
471 0 : while (true) {
472 0 : unsigned count = 0;
473 :
474 0 : blk_mq_tagset_busy_iter(tagset,
475 : blk_mq_tagset_count_completed_rqs, &count);
476 0 : if (!count)
477 : break;
478 0 : msleep(5);
479 : }
480 0 : }
481 : EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
482 :
483 : /**
484 : * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag
485 : * @q: Request queue to examine.
486 : * @fn: Pointer to the function that will be called for each request
487 : * on @q. @fn will be called as follows: @fn(hctx, rq, @priv,
488 : * reserved) where rq is a pointer to a request and hctx points
489 : * to the hardware queue associated with the request. 'reserved'
490 : * indicates whether or not @rq is a reserved request.
491 : * @priv: Will be passed as third argument to @fn.
492 : *
493 : * Note: if @q->tag_set is shared with other request queues then @fn will be
494 : * called for all requests on all queues that share that tag set and not only
495 : * for requests associated with @q.
496 : */
497 0 : void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn,
498 : void *priv)
499 : {
500 : /*
501 : * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and hctx_table
502 : * while the queue is frozen. So we can use q_usage_counter to avoid
503 : * racing with it.
504 : */
505 0 : if (!percpu_ref_tryget(&q->q_usage_counter))
506 : return;
507 :
508 0 : if (blk_mq_is_shared_tags(q->tag_set->flags)) {
509 0 : struct blk_mq_tags *tags = q->tag_set->shared_tags;
510 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
511 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
512 :
513 0 : if (tags->nr_reserved_tags)
514 : bt_for_each(NULL, q, bresv, fn, priv, true);
515 : bt_for_each(NULL, q, btags, fn, priv, false);
516 : } else {
517 : struct blk_mq_hw_ctx *hctx;
518 : unsigned long i;
519 :
520 0 : queue_for_each_hw_ctx(q, hctx, i) {
521 0 : struct blk_mq_tags *tags = hctx->tags;
522 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
523 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
524 :
525 : /*
526 : * If no software queues are currently mapped to this
527 : * hardware queue, there's nothing to check
528 : */
529 0 : if (!blk_mq_hw_queue_mapped(hctx))
530 0 : continue;
531 :
532 0 : if (tags->nr_reserved_tags)
533 : bt_for_each(hctx, q, bresv, fn, priv, true);
534 : bt_for_each(hctx, q, btags, fn, priv, false);
535 : }
536 : }
537 0 : blk_queue_exit(q);
538 : }
539 :
540 : static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
541 : bool round_robin, int node)
542 : {
543 0 : return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
544 : node);
545 : }
546 :
547 0 : int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags,
548 : struct sbitmap_queue *breserved_tags,
549 : unsigned int queue_depth, unsigned int reserved,
550 : int node, int alloc_policy)
551 : {
552 0 : unsigned int depth = queue_depth - reserved;
553 0 : bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
554 :
555 0 : if (bt_alloc(bitmap_tags, depth, round_robin, node))
556 : return -ENOMEM;
557 0 : if (bt_alloc(breserved_tags, reserved, round_robin, node))
558 : goto free_bitmap_tags;
559 :
560 : return 0;
561 :
562 : free_bitmap_tags:
563 0 : sbitmap_queue_free(bitmap_tags);
564 0 : return -ENOMEM;
565 : }
566 :
567 0 : struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
568 : unsigned int reserved_tags,
569 : int node, int alloc_policy)
570 : {
571 : struct blk_mq_tags *tags;
572 :
573 0 : if (total_tags > BLK_MQ_TAG_MAX) {
574 0 : pr_err("blk-mq: tag depth too large\n");
575 0 : return NULL;
576 : }
577 :
578 0 : tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
579 0 : if (!tags)
580 : return NULL;
581 :
582 0 : tags->nr_tags = total_tags;
583 0 : tags->nr_reserved_tags = reserved_tags;
584 0 : spin_lock_init(&tags->lock);
585 :
586 0 : if (blk_mq_init_bitmaps(&tags->bitmap_tags, &tags->breserved_tags,
587 : total_tags, reserved_tags, node,
588 : alloc_policy) < 0) {
589 0 : kfree(tags);
590 0 : return NULL;
591 : }
592 : return tags;
593 : }
594 :
595 0 : void blk_mq_free_tags(struct blk_mq_tags *tags)
596 : {
597 0 : sbitmap_queue_free(&tags->bitmap_tags);
598 0 : sbitmap_queue_free(&tags->breserved_tags);
599 0 : kfree(tags);
600 0 : }
601 :
602 0 : int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
603 : struct blk_mq_tags **tagsptr, unsigned int tdepth,
604 : bool can_grow)
605 : {
606 0 : struct blk_mq_tags *tags = *tagsptr;
607 :
608 0 : if (tdepth <= tags->nr_reserved_tags)
609 : return -EINVAL;
610 :
611 : /*
612 : * If we are allowed to grow beyond the original size, allocate
613 : * a new set of tags before freeing the old one.
614 : */
615 0 : if (tdepth > tags->nr_tags) {
616 0 : struct blk_mq_tag_set *set = hctx->queue->tag_set;
617 : struct blk_mq_tags *new;
618 :
619 0 : if (!can_grow)
620 : return -EINVAL;
621 :
622 : /*
623 : * We need some sort of upper limit, set it high enough that
624 : * no valid use cases should require more.
625 : */
626 0 : if (tdepth > MAX_SCHED_RQ)
627 : return -EINVAL;
628 :
629 : /*
630 : * Only the sbitmap needs resizing since we allocated the max
631 : * initially.
632 : */
633 0 : if (blk_mq_is_shared_tags(set->flags))
634 : return 0;
635 :
636 0 : new = blk_mq_alloc_map_and_rqs(set, hctx->queue_num, tdepth);
637 0 : if (!new)
638 : return -ENOMEM;
639 :
640 0 : blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num);
641 0 : *tagsptr = new;
642 : } else {
643 : /*
644 : * Don't need (or can't) update reserved tags here, they
645 : * remain static and should never need resizing.
646 : */
647 0 : sbitmap_queue_resize(&tags->bitmap_tags,
648 : tdepth - tags->nr_reserved_tags);
649 : }
650 :
651 : return 0;
652 : }
653 :
654 0 : void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size)
655 : {
656 0 : struct blk_mq_tags *tags = set->shared_tags;
657 :
658 0 : sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags);
659 0 : }
660 :
661 0 : void blk_mq_tag_update_sched_shared_tags(struct request_queue *q)
662 : {
663 0 : sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags,
664 0 : q->nr_requests - q->tag_set->reserved_tags);
665 0 : }
666 :
667 : /**
668 : * blk_mq_unique_tag() - return a tag that is unique queue-wide
669 : * @rq: request for which to compute a unique tag
670 : *
671 : * The tag field in struct request is unique per hardware queue but not over
672 : * all hardware queues. Hence this function that returns a tag with the
673 : * hardware context index in the upper bits and the per hardware queue tag in
674 : * the lower bits.
675 : *
676 : * Note: When called for a request that is queued on a non-multiqueue request
677 : * queue, the hardware context index is set to zero.
678 : */
679 0 : u32 blk_mq_unique_tag(struct request *rq)
680 : {
681 0 : return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
682 0 : (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
683 : }
684 : EXPORT_SYMBOL(blk_mq_unique_tag);
|
