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-tag.h"
17 :
18 : /*
19 : * If a previously inactive queue goes active, bump the active user count.
20 : * We need to do this before try to allocate driver tag, then even if fail
21 : * to get tag when first time, the other shared-tag users could reserve
22 : * budget for it.
23 : */
24 0 : bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
25 : {
26 0 : if (blk_mq_is_sbitmap_shared(hctx->flags)) {
27 0 : struct request_queue *q = hctx->queue;
28 0 : struct blk_mq_tag_set *set = q->tag_set;
29 :
30 0 : if (!test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) &&
31 0 : !test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
32 0 : atomic_inc(&set->active_queues_shared_sbitmap);
33 : } else {
34 0 : if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
35 0 : !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
36 0 : atomic_inc(&hctx->tags->active_queues);
37 : }
38 :
39 0 : return true;
40 : }
41 :
42 : /*
43 : * Wakeup all potentially sleeping on tags
44 : */
45 0 : void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
46 : {
47 0 : sbitmap_queue_wake_all(tags->bitmap_tags);
48 0 : if (include_reserve)
49 0 : sbitmap_queue_wake_all(tags->breserved_tags);
50 0 : }
51 :
52 : /*
53 : * If a previously busy queue goes inactive, potential waiters could now
54 : * be allowed to queue. Wake them up and check.
55 : */
56 0 : void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
57 : {
58 0 : struct blk_mq_tags *tags = hctx->tags;
59 0 : struct request_queue *q = hctx->queue;
60 0 : struct blk_mq_tag_set *set = q->tag_set;
61 :
62 0 : if (blk_mq_is_sbitmap_shared(hctx->flags)) {
63 0 : if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
64 0 : &q->queue_flags))
65 : return;
66 0 : atomic_dec(&set->active_queues_shared_sbitmap);
67 : } else {
68 0 : if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
69 : return;
70 0 : atomic_dec(&tags->active_queues);
71 : }
72 :
73 0 : blk_mq_tag_wakeup_all(tags, false);
74 : }
75 :
76 3255 : static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
77 : struct sbitmap_queue *bt)
78 : {
79 6508 : if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
80 3254 : !hctx_may_queue(data->hctx, bt))
81 : return BLK_MQ_NO_TAG;
82 :
83 3254 : if (data->shallow_depth)
84 0 : return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
85 : else
86 3254 : return __sbitmap_queue_get(bt);
87 : }
88 :
89 3254 : unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
90 : {
91 3254 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
92 3254 : struct sbitmap_queue *bt;
93 3254 : struct sbq_wait_state *ws;
94 3254 : DEFINE_SBQ_WAIT(wait);
95 3254 : unsigned int tag_offset;
96 3254 : int tag;
97 :
98 3254 : if (data->flags & BLK_MQ_REQ_RESERVED) {
99 0 : if (unlikely(!tags->nr_reserved_tags)) {
100 0 : WARN_ON_ONCE(1);
101 0 : return BLK_MQ_NO_TAG;
102 : }
103 0 : bt = tags->breserved_tags;
104 0 : tag_offset = 0;
105 : } else {
106 3254 : bt = tags->bitmap_tags;
107 3254 : tag_offset = tags->nr_reserved_tags;
108 : }
109 :
110 3254 : tag = __blk_mq_get_tag(data, bt);
111 3252 : if (tag != BLK_MQ_NO_TAG)
112 3252 : goto found_tag;
113 :
114 0 : if (data->flags & BLK_MQ_REQ_NOWAIT)
115 : return BLK_MQ_NO_TAG;
116 :
117 0 : ws = bt_wait_ptr(bt, data->hctx);
118 0 : do {
119 0 : struct sbitmap_queue *bt_prev;
120 :
121 : /*
122 : * We're out of tags on this hardware queue, kick any
123 : * pending IO submits before going to sleep waiting for
124 : * some to complete.
125 : */
126 0 : blk_mq_run_hw_queue(data->hctx, false);
127 :
128 : /*
129 : * Retry tag allocation after running the hardware queue,
130 : * as running the queue may also have found completions.
131 : */
132 0 : tag = __blk_mq_get_tag(data, bt);
133 0 : if (tag != BLK_MQ_NO_TAG)
134 : break;
135 :
136 0 : sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
137 :
138 0 : tag = __blk_mq_get_tag(data, bt);
139 0 : if (tag != BLK_MQ_NO_TAG)
140 : break;
141 :
142 0 : bt_prev = bt;
143 0 : io_schedule();
144 :
145 0 : sbitmap_finish_wait(bt, ws, &wait);
146 :
147 0 : data->ctx = blk_mq_get_ctx(data->q);
148 0 : data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
149 : data->ctx);
150 0 : tags = blk_mq_tags_from_data(data);
151 0 : if (data->flags & BLK_MQ_REQ_RESERVED)
152 0 : bt = tags->breserved_tags;
153 : else
154 0 : bt = tags->bitmap_tags;
155 :
156 : /*
157 : * If destination hw queue is changed, fake wake up on
158 : * previous queue for compensating the wake up miss, so
159 : * other allocations on previous queue won't be starved.
160 : */
161 0 : if (bt != bt_prev)
162 0 : sbitmap_queue_wake_up(bt_prev);
163 :
164 0 : ws = bt_wait_ptr(bt, data->hctx);
165 : } while (1);
166 :
167 0 : sbitmap_finish_wait(bt, ws, &wait);
168 :
169 3252 : found_tag:
170 : /*
171 : * Give up this allocation if the hctx is inactive. The caller will
172 : * retry on an active hctx.
173 : */
174 3252 : if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
175 0 : blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
176 0 : return BLK_MQ_NO_TAG;
177 : }
178 3254 : return tag + tag_offset;
179 : }
180 :
181 3254 : void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
182 : unsigned int tag)
183 : {
184 3254 : if (!blk_mq_tag_is_reserved(tags, tag)) {
185 3254 : const int real_tag = tag - tags->nr_reserved_tags;
186 :
187 3254 : BUG_ON(real_tag >= tags->nr_tags);
188 3254 : sbitmap_queue_clear(tags->bitmap_tags, real_tag, ctx->cpu);
189 : } else {
190 0 : BUG_ON(tag >= tags->nr_reserved_tags);
191 0 : sbitmap_queue_clear(tags->breserved_tags, tag, ctx->cpu);
192 : }
193 3254 : }
194 :
195 : struct bt_iter_data {
196 : struct blk_mq_hw_ctx *hctx;
197 : busy_iter_fn *fn;
198 : void *data;
199 : bool reserved;
200 : };
201 :
202 1 : static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
203 : {
204 1 : struct bt_iter_data *iter_data = data;
205 1 : struct blk_mq_hw_ctx *hctx = iter_data->hctx;
206 1 : struct blk_mq_tags *tags = hctx->tags;
207 1 : bool reserved = iter_data->reserved;
208 1 : struct request *rq;
209 :
210 1 : if (!reserved)
211 1 : bitnr += tags->nr_reserved_tags;
212 1 : rq = tags->rqs[bitnr];
213 :
214 : /*
215 : * We can hit rq == NULL here, because the tagging functions
216 : * test and set the bit before assigning ->rqs[].
217 : */
218 1 : if (rq && rq->q == hctx->queue && rq->mq_hctx == hctx)
219 1 : return iter_data->fn(hctx, rq, iter_data->data, reserved);
220 : return true;
221 : }
222 :
223 : /**
224 : * bt_for_each - iterate over the requests associated with a hardware queue
225 : * @hctx: Hardware queue to examine.
226 : * @bt: sbitmap to examine. This is either the breserved_tags member
227 : * or the bitmap_tags member of struct blk_mq_tags.
228 : * @fn: Pointer to the function that will be called for each request
229 : * associated with @hctx that has been assigned a driver tag.
230 : * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
231 : * where rq is a pointer to a request. Return true to continue
232 : * iterating tags, false to stop.
233 : * @data: Will be passed as third argument to @fn.
234 : * @reserved: Indicates whether @bt is the breserved_tags member or the
235 : * bitmap_tags member of struct blk_mq_tags.
236 : */
237 8 : static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
238 : busy_iter_fn *fn, void *data, bool reserved)
239 : {
240 8 : struct bt_iter_data iter_data = {
241 : .hctx = hctx,
242 : .fn = fn,
243 : .data = data,
244 : .reserved = reserved,
245 : };
246 :
247 16 : sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
248 8 : }
249 :
250 : struct bt_tags_iter_data {
251 : struct blk_mq_tags *tags;
252 : busy_tag_iter_fn *fn;
253 : void *data;
254 : unsigned int flags;
255 : };
256 :
257 : #define BT_TAG_ITER_RESERVED (1 << 0)
258 : #define BT_TAG_ITER_STARTED (1 << 1)
259 : #define BT_TAG_ITER_STATIC_RQS (1 << 2)
260 :
261 0 : static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
262 : {
263 0 : struct bt_tags_iter_data *iter_data = data;
264 0 : struct blk_mq_tags *tags = iter_data->tags;
265 0 : bool reserved = iter_data->flags & BT_TAG_ITER_RESERVED;
266 0 : struct request *rq;
267 :
268 0 : if (!reserved)
269 0 : bitnr += tags->nr_reserved_tags;
270 :
271 : /*
272 : * We can hit rq == NULL here, because the tagging functions
273 : * test and set the bit before assigning ->rqs[].
274 : */
275 0 : if (iter_data->flags & BT_TAG_ITER_STATIC_RQS)
276 0 : rq = tags->static_rqs[bitnr];
277 : else
278 0 : rq = tags->rqs[bitnr];
279 0 : if (!rq)
280 : return true;
281 0 : if ((iter_data->flags & BT_TAG_ITER_STARTED) &&
282 0 : !blk_mq_request_started(rq))
283 : return true;
284 0 : return iter_data->fn(rq, iter_data->data, reserved);
285 : }
286 :
287 : /**
288 : * bt_tags_for_each - iterate over the requests in a tag map
289 : * @tags: Tag map to iterate over.
290 : * @bt: sbitmap to examine. This is either the breserved_tags member
291 : * or the bitmap_tags member of struct blk_mq_tags.
292 : * @fn: Pointer to the function that will be called for each started
293 : * request. @fn will be called as follows: @fn(rq, @data,
294 : * @reserved) where rq is a pointer to a request. Return true
295 : * to continue iterating tags, false to stop.
296 : * @data: Will be passed as second argument to @fn.
297 : * @flags: BT_TAG_ITER_*
298 : */
299 0 : static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
300 : busy_tag_iter_fn *fn, void *data, unsigned int flags)
301 : {
302 0 : struct bt_tags_iter_data iter_data = {
303 : .tags = tags,
304 : .fn = fn,
305 : .data = data,
306 : .flags = flags,
307 : };
308 :
309 0 : if (tags->rqs)
310 0 : sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
311 0 : }
312 :
313 0 : static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags,
314 : busy_tag_iter_fn *fn, void *priv, unsigned int flags)
315 : {
316 0 : WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED);
317 :
318 0 : if (tags->nr_reserved_tags)
319 0 : bt_tags_for_each(tags, tags->breserved_tags, fn, priv,
320 : flags | BT_TAG_ITER_RESERVED);
321 0 : bt_tags_for_each(tags, tags->bitmap_tags, fn, priv, flags);
322 0 : }
323 :
324 : /**
325 : * blk_mq_all_tag_iter - iterate over all requests in a tag map
326 : * @tags: Tag map to iterate over.
327 : * @fn: Pointer to the function that will be called for each
328 : * request. @fn will be called as follows: @fn(rq, @priv,
329 : * reserved) where rq is a pointer to a request. 'reserved'
330 : * indicates whether or not @rq is a reserved request. Return
331 : * true to continue iterating tags, false to stop.
332 : * @priv: Will be passed as second argument to @fn.
333 : *
334 : * Caller has to pass the tag map from which requests are allocated.
335 : */
336 0 : void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
337 : void *priv)
338 : {
339 0 : __blk_mq_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS);
340 0 : }
341 :
342 : /**
343 : * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set
344 : * @tagset: Tag set to iterate over.
345 : * @fn: Pointer to the function that will be called for each started
346 : * request. @fn will be called as follows: @fn(rq, @priv,
347 : * reserved) where rq is a pointer to a request. 'reserved'
348 : * indicates whether or not @rq is a reserved request. Return
349 : * true to continue iterating tags, false to stop.
350 : * @priv: Will be passed as second argument to @fn.
351 : */
352 0 : void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
353 : busy_tag_iter_fn *fn, void *priv)
354 : {
355 0 : int i;
356 :
357 0 : for (i = 0; i < tagset->nr_hw_queues; i++) {
358 0 : if (tagset->tags && tagset->tags[i])
359 0 : __blk_mq_all_tag_iter(tagset->tags[i], fn, priv,
360 : BT_TAG_ITER_STARTED);
361 : }
362 0 : }
363 : EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
364 :
365 0 : static bool blk_mq_tagset_count_completed_rqs(struct request *rq,
366 : void *data, bool reserved)
367 : {
368 0 : unsigned *count = data;
369 :
370 0 : if (blk_mq_request_completed(rq))
371 0 : (*count)++;
372 0 : return true;
373 : }
374 :
375 : /**
376 : * blk_mq_tagset_wait_completed_request - wait until all completed req's
377 : * complete funtion is run
378 : * @tagset: Tag set to drain completed request
379 : *
380 : * Note: This function has to be run after all IO queues are shutdown
381 : */
382 0 : void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset)
383 : {
384 0 : while (true) {
385 0 : unsigned count = 0;
386 :
387 0 : blk_mq_tagset_busy_iter(tagset,
388 : blk_mq_tagset_count_completed_rqs, &count);
389 0 : if (!count)
390 : break;
391 0 : msleep(5);
392 : }
393 0 : }
394 : EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
395 :
396 : /**
397 : * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag
398 : * @q: Request queue to examine.
399 : * @fn: Pointer to the function that will be called for each request
400 : * on @q. @fn will be called as follows: @fn(hctx, rq, @priv,
401 : * reserved) where rq is a pointer to a request and hctx points
402 : * to the hardware queue associated with the request. 'reserved'
403 : * indicates whether or not @rq is a reserved request.
404 : * @priv: Will be passed as third argument to @fn.
405 : *
406 : * Note: if @q->tag_set is shared with other request queues then @fn will be
407 : * called for all requests on all queues that share that tag set and not only
408 : * for requests associated with @q.
409 : */
410 8 : void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
411 : void *priv)
412 : {
413 8 : struct blk_mq_hw_ctx *hctx;
414 8 : int i;
415 :
416 : /*
417 : * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and queue_hw_ctx
418 : * while the queue is frozen. So we can use q_usage_counter to avoid
419 : * racing with it.
420 : */
421 8 : if (!percpu_ref_tryget(&q->q_usage_counter))
422 : return;
423 :
424 16 : queue_for_each_hw_ctx(q, hctx, i) {
425 8 : struct blk_mq_tags *tags = hctx->tags;
426 :
427 : /*
428 : * If no software queues are currently mapped to this
429 : * hardware queue, there's nothing to check
430 : */
431 16 : if (!blk_mq_hw_queue_mapped(hctx))
432 0 : continue;
433 :
434 8 : if (tags->nr_reserved_tags)
435 0 : bt_for_each(hctx, tags->breserved_tags, fn, priv, true);
436 16 : bt_for_each(hctx, tags->bitmap_tags, fn, priv, false);
437 : }
438 8 : blk_queue_exit(q);
439 : }
440 :
441 18 : static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
442 : bool round_robin, int node)
443 : {
444 18 : return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
445 : node);
446 : }
447 :
448 9 : static int blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
449 : int node, int alloc_policy)
450 : {
451 9 : unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
452 9 : bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
453 :
454 9 : if (bt_alloc(&tags->__bitmap_tags, depth, round_robin, node))
455 : return -ENOMEM;
456 9 : if (bt_alloc(&tags->__breserved_tags, tags->nr_reserved_tags,
457 : round_robin, node))
458 0 : goto free_bitmap_tags;
459 :
460 9 : tags->bitmap_tags = &tags->__bitmap_tags;
461 9 : tags->breserved_tags = &tags->__breserved_tags;
462 :
463 9 : return 0;
464 0 : free_bitmap_tags:
465 0 : sbitmap_queue_free(&tags->__bitmap_tags);
466 0 : return -ENOMEM;
467 : }
468 :
469 0 : int blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *set, unsigned int flags)
470 : {
471 0 : unsigned int depth = set->queue_depth - set->reserved_tags;
472 0 : int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags);
473 0 : bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
474 0 : int i, node = set->numa_node;
475 :
476 0 : if (bt_alloc(&set->__bitmap_tags, depth, round_robin, node))
477 : return -ENOMEM;
478 0 : if (bt_alloc(&set->__breserved_tags, set->reserved_tags,
479 : round_robin, node))
480 0 : goto free_bitmap_tags;
481 :
482 0 : for (i = 0; i < set->nr_hw_queues; i++) {
483 0 : struct blk_mq_tags *tags = set->tags[i];
484 :
485 0 : tags->bitmap_tags = &set->__bitmap_tags;
486 0 : tags->breserved_tags = &set->__breserved_tags;
487 : }
488 :
489 : return 0;
490 0 : free_bitmap_tags:
491 0 : sbitmap_queue_free(&set->__bitmap_tags);
492 0 : return -ENOMEM;
493 : }
494 :
495 0 : void blk_mq_exit_shared_sbitmap(struct blk_mq_tag_set *set)
496 : {
497 0 : sbitmap_queue_free(&set->__bitmap_tags);
498 0 : sbitmap_queue_free(&set->__breserved_tags);
499 0 : }
500 :
501 9 : struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
502 : unsigned int reserved_tags,
503 : int node, unsigned int flags)
504 : {
505 9 : int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(flags);
506 9 : struct blk_mq_tags *tags;
507 :
508 9 : if (total_tags > BLK_MQ_TAG_MAX) {
509 0 : pr_err("blk-mq: tag depth too large\n");
510 0 : return NULL;
511 : }
512 :
513 9 : tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
514 9 : if (!tags)
515 : return NULL;
516 :
517 9 : tags->nr_tags = total_tags;
518 9 : tags->nr_reserved_tags = reserved_tags;
519 :
520 9 : if (flags & BLK_MQ_F_TAG_HCTX_SHARED)
521 : return tags;
522 :
523 9 : if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
524 0 : kfree(tags);
525 0 : return NULL;
526 : }
527 : return tags;
528 : }
529 :
530 0 : void blk_mq_free_tags(struct blk_mq_tags *tags, unsigned int flags)
531 : {
532 0 : if (!(flags & BLK_MQ_F_TAG_HCTX_SHARED)) {
533 0 : sbitmap_queue_free(tags->bitmap_tags);
534 0 : sbitmap_queue_free(tags->breserved_tags);
535 : }
536 0 : kfree(tags);
537 0 : }
538 :
539 0 : int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
540 : struct blk_mq_tags **tagsptr, unsigned int tdepth,
541 : bool can_grow)
542 : {
543 0 : struct blk_mq_tags *tags = *tagsptr;
544 :
545 0 : if (tdepth <= tags->nr_reserved_tags)
546 : return -EINVAL;
547 :
548 : /*
549 : * If we are allowed to grow beyond the original size, allocate
550 : * a new set of tags before freeing the old one.
551 : */
552 0 : if (tdepth > tags->nr_tags) {
553 0 : struct blk_mq_tag_set *set = hctx->queue->tag_set;
554 : /* Only sched tags can grow, so clear HCTX_SHARED flag */
555 0 : unsigned int flags = set->flags & ~BLK_MQ_F_TAG_HCTX_SHARED;
556 0 : struct blk_mq_tags *new;
557 0 : bool ret;
558 :
559 0 : if (!can_grow)
560 : return -EINVAL;
561 :
562 : /*
563 : * We need some sort of upper limit, set it high enough that
564 : * no valid use cases should require more.
565 : */
566 0 : if (tdepth > 16 * BLKDEV_MAX_RQ)
567 : return -EINVAL;
568 :
569 0 : new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth,
570 : tags->nr_reserved_tags, flags);
571 0 : if (!new)
572 : return -ENOMEM;
573 0 : ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
574 0 : if (ret) {
575 0 : blk_mq_free_rq_map(new, flags);
576 0 : return -ENOMEM;
577 : }
578 :
579 0 : blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
580 0 : blk_mq_free_rq_map(*tagsptr, flags);
581 0 : *tagsptr = new;
582 : } else {
583 : /*
584 : * Don't need (or can't) update reserved tags here, they
585 : * remain static and should never need resizing.
586 : */
587 0 : sbitmap_queue_resize(tags->bitmap_tags,
588 : tdepth - tags->nr_reserved_tags);
589 : }
590 :
591 : return 0;
592 : }
593 :
594 0 : void blk_mq_tag_resize_shared_sbitmap(struct blk_mq_tag_set *set, unsigned int size)
595 : {
596 0 : sbitmap_queue_resize(&set->__bitmap_tags, size - set->reserved_tags);
597 0 : }
598 :
599 : /**
600 : * blk_mq_unique_tag() - return a tag that is unique queue-wide
601 : * @rq: request for which to compute a unique tag
602 : *
603 : * The tag field in struct request is unique per hardware queue but not over
604 : * all hardware queues. Hence this function that returns a tag with the
605 : * hardware context index in the upper bits and the per hardware queue tag in
606 : * the lower bits.
607 : *
608 : * Note: When called for a request that is queued on a non-multiqueue request
609 : * queue, the hardware context index is set to zero.
610 : */
611 0 : u32 blk_mq_unique_tag(struct request *rq)
612 : {
613 0 : return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
614 0 : (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
615 : }
616 : EXPORT_SYMBOL(blk_mq_unique_tag);
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