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/delay.h>
13 : #include "blk.h"
14 : #include "blk-mq.h"
15 : #include "blk-mq-sched.h"
16 :
17 : /*
18 : * Recalculate wakeup batch when tag is shared by hctx.
19 : */
20 0 : static void blk_mq_update_wake_batch(struct blk_mq_tags *tags,
21 : unsigned int users)
22 : {
23 0 : if (!users)
24 : return;
25 :
26 0 : sbitmap_queue_recalculate_wake_batch(&tags->bitmap_tags,
27 : users);
28 0 : sbitmap_queue_recalculate_wake_batch(&tags->breserved_tags,
29 : users);
30 : }
31 :
32 : /*
33 : * If a previously inactive queue goes active, bump the active user count.
34 : * We need to do this before try to allocate driver tag, then even if fail
35 : * to get tag when first time, the other shared-tag users could reserve
36 : * budget for it.
37 : */
38 0 : void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
39 : {
40 : unsigned int users;
41 0 : struct blk_mq_tags *tags = hctx->tags;
42 :
43 : /*
44 : * calling test_bit() prior to test_and_set_bit() is intentional,
45 : * it avoids dirtying the cacheline if the queue is already active.
46 : */
47 0 : if (blk_mq_is_shared_tags(hctx->flags)) {
48 0 : struct request_queue *q = hctx->queue;
49 :
50 0 : if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) ||
51 0 : test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
52 : return;
53 : } else {
54 0 : if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) ||
55 0 : test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
56 : return;
57 : }
58 :
59 0 : spin_lock_irq(&tags->lock);
60 0 : users = tags->active_queues + 1;
61 0 : WRITE_ONCE(tags->active_queues, users);
62 0 : blk_mq_update_wake_batch(tags, users);
63 0 : spin_unlock_irq(&tags->lock);
64 : }
65 :
66 : /*
67 : * Wakeup all potentially sleeping on tags
68 : */
69 0 : void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
70 : {
71 0 : sbitmap_queue_wake_all(&tags->bitmap_tags);
72 0 : if (include_reserve)
73 0 : sbitmap_queue_wake_all(&tags->breserved_tags);
74 0 : }
75 :
76 : /*
77 : * If a previously busy queue goes inactive, potential waiters could now
78 : * be allowed to queue. Wake them up and check.
79 : */
80 0 : void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
81 : {
82 0 : struct blk_mq_tags *tags = hctx->tags;
83 : unsigned int users;
84 :
85 0 : if (blk_mq_is_shared_tags(hctx->flags)) {
86 0 : struct request_queue *q = hctx->queue;
87 :
88 0 : if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
89 0 : &q->queue_flags))
90 : return;
91 : } else {
92 0 : if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
93 : return;
94 : }
95 :
96 0 : spin_lock_irq(&tags->lock);
97 0 : users = tags->active_queues - 1;
98 0 : WRITE_ONCE(tags->active_queues, users);
99 0 : blk_mq_update_wake_batch(tags, users);
100 0 : spin_unlock_irq(&tags->lock);
101 :
102 : blk_mq_tag_wakeup_all(tags, false);
103 : }
104 :
105 0 : static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
106 : struct sbitmap_queue *bt)
107 : {
108 0 : if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
109 0 : !hctx_may_queue(data->hctx, bt))
110 : return BLK_MQ_NO_TAG;
111 :
112 0 : if (data->shallow_depth)
113 0 : return sbitmap_queue_get_shallow(bt, data->shallow_depth);
114 : else
115 0 : return __sbitmap_queue_get(bt);
116 : }
117 :
118 0 : unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags,
119 : unsigned int *offset)
120 : {
121 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
122 0 : struct sbitmap_queue *bt = &tags->bitmap_tags;
123 : unsigned long ret;
124 :
125 0 : if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED ||
126 0 : data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
127 : return 0;
128 0 : ret = __sbitmap_queue_get_batch(bt, nr_tags, offset);
129 0 : *offset += tags->nr_reserved_tags;
130 0 : return ret;
131 : }
132 :
133 0 : unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
134 : {
135 0 : struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
136 : struct sbitmap_queue *bt;
137 : struct sbq_wait_state *ws;
138 0 : DEFINE_SBQ_WAIT(wait);
139 : unsigned int tag_offset;
140 : int tag;
141 :
142 0 : if (data->flags & BLK_MQ_REQ_RESERVED) {
143 0 : if (unlikely(!tags->nr_reserved_tags)) {
144 0 : WARN_ON_ONCE(1);
145 : return BLK_MQ_NO_TAG;
146 : }
147 0 : bt = &tags->breserved_tags;
148 0 : tag_offset = 0;
149 : } else {
150 0 : bt = &tags->bitmap_tags;
151 0 : tag_offset = tags->nr_reserved_tags;
152 : }
153 :
154 0 : tag = __blk_mq_get_tag(data, bt);
155 0 : if (tag != BLK_MQ_NO_TAG)
156 : goto found_tag;
157 :
158 0 : if (data->flags & BLK_MQ_REQ_NOWAIT)
159 : return BLK_MQ_NO_TAG;
160 :
161 0 : ws = bt_wait_ptr(bt, data->hctx);
162 : do {
163 : struct sbitmap_queue *bt_prev;
164 :
165 : /*
166 : * We're out of tags on this hardware queue, kick any
167 : * pending IO submits before going to sleep waiting for
168 : * some to complete.
169 : */
170 0 : blk_mq_run_hw_queue(data->hctx, false);
171 :
172 : /*
173 : * Retry tag allocation after running the hardware queue,
174 : * as running the queue may also have found completions.
175 : */
176 0 : tag = __blk_mq_get_tag(data, bt);
177 0 : if (tag != BLK_MQ_NO_TAG)
178 : break;
179 :
180 0 : sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
181 :
182 0 : tag = __blk_mq_get_tag(data, bt);
183 0 : if (tag != BLK_MQ_NO_TAG)
184 : break;
185 :
186 0 : bt_prev = bt;
187 0 : io_schedule();
188 :
189 0 : sbitmap_finish_wait(bt, ws, &wait);
190 :
191 0 : data->ctx = blk_mq_get_ctx(data->q);
192 0 : data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
193 : data->ctx);
194 0 : tags = blk_mq_tags_from_data(data);
195 0 : if (data->flags & BLK_MQ_REQ_RESERVED)
196 0 : bt = &tags->breserved_tags;
197 : else
198 0 : bt = &tags->bitmap_tags;
199 :
200 : /*
201 : * If destination hw queue is changed, fake wake up on
202 : * previous queue for compensating the wake up miss, so
203 : * other allocations on previous queue won't be starved.
204 : */
205 0 : if (bt != bt_prev)
206 0 : sbitmap_queue_wake_up(bt_prev, 1);
207 :
208 0 : ws = bt_wait_ptr(bt, data->hctx);
209 : } while (1);
210 :
211 0 : sbitmap_finish_wait(bt, ws, &wait);
212 :
213 : found_tag:
214 : /*
215 : * Give up this allocation if the hctx is inactive. The caller will
216 : * retry on an active hctx.
217 : */
218 0 : if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
219 0 : blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
220 0 : return BLK_MQ_NO_TAG;
221 : }
222 0 : return tag + tag_offset;
223 : }
224 :
225 0 : void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
226 : unsigned int tag)
227 : {
228 0 : if (!blk_mq_tag_is_reserved(tags, tag)) {
229 0 : const int real_tag = tag - tags->nr_reserved_tags;
230 :
231 0 : BUG_ON(real_tag >= tags->nr_tags);
232 0 : sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
233 : } else {
234 0 : sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
235 : }
236 0 : }
237 :
238 0 : void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags)
239 : {
240 0 : sbitmap_queue_clear_batch(&tags->bitmap_tags, tags->nr_reserved_tags,
241 : tag_array, nr_tags);
242 0 : }
243 :
244 : struct bt_iter_data {
245 : struct blk_mq_hw_ctx *hctx;
246 : struct request_queue *q;
247 : busy_tag_iter_fn *fn;
248 : void *data;
249 : bool reserved;
250 : };
251 :
252 0 : static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
253 : unsigned int bitnr)
254 : {
255 : struct request *rq;
256 : unsigned long flags;
257 :
258 0 : spin_lock_irqsave(&tags->lock, flags);
259 0 : rq = tags->rqs[bitnr];
260 0 : if (!rq || rq->tag != bitnr || !req_ref_inc_not_zero(rq))
261 : rq = NULL;
262 0 : spin_unlock_irqrestore(&tags->lock, flags);
263 0 : return rq;
264 : }
265 :
266 0 : static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
267 : {
268 0 : struct bt_iter_data *iter_data = data;
269 0 : struct blk_mq_hw_ctx *hctx = iter_data->hctx;
270 0 : struct request_queue *q = iter_data->q;
271 0 : struct blk_mq_tag_set *set = q->tag_set;
272 : struct blk_mq_tags *tags;
273 : struct request *rq;
274 0 : bool ret = true;
275 :
276 0 : if (blk_mq_is_shared_tags(set->flags))
277 0 : tags = set->shared_tags;
278 : else
279 0 : tags = hctx->tags;
280 :
281 0 : if (!iter_data->reserved)
282 0 : bitnr += tags->nr_reserved_tags;
283 : /*
284 : * We can hit rq == NULL here, because the tagging functions
285 : * test and set the bit before assigning ->rqs[].
286 : */
287 0 : rq = blk_mq_find_and_get_req(tags, bitnr);
288 0 : if (!rq)
289 : return true;
290 :
291 0 : if (rq->q == q && (!hctx || rq->mq_hctx == hctx))
292 0 : ret = iter_data->fn(rq, iter_data->data);
293 0 : blk_mq_put_rq_ref(rq);
294 0 : return ret;
295 : }
296 :
297 : /**
298 : * bt_for_each - iterate over the requests associated with a hardware queue
299 : * @hctx: Hardware queue to examine.
300 : * @q: Request queue to examine.
301 : * @bt: sbitmap to examine. This is either the breserved_tags member
302 : * or the bitmap_tags member of struct blk_mq_tags.
303 : * @fn: Pointer to the function that will be called for each request
304 : * associated with @hctx that has been assigned a driver tag.
305 : * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
306 : * where rq is a pointer to a request. Return true to continue
307 : * iterating tags, false to stop.
308 : * @data: Will be passed as third argument to @fn.
309 : * @reserved: Indicates whether @bt is the breserved_tags member or the
310 : * bitmap_tags member of struct blk_mq_tags.
311 : */
312 : static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct request_queue *q,
313 : struct sbitmap_queue *bt, busy_tag_iter_fn *fn,
314 : void *data, bool reserved)
315 : {
316 0 : struct bt_iter_data iter_data = {
317 : .hctx = hctx,
318 : .fn = fn,
319 : .data = data,
320 : .reserved = reserved,
321 : .q = q,
322 : };
323 :
324 0 : sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
325 : }
326 :
327 : struct bt_tags_iter_data {
328 : struct blk_mq_tags *tags;
329 : busy_tag_iter_fn *fn;
330 : void *data;
331 : unsigned int flags;
332 : };
333 :
334 : #define BT_TAG_ITER_RESERVED (1 << 0)
335 : #define BT_TAG_ITER_STARTED (1 << 1)
336 : #define BT_TAG_ITER_STATIC_RQS (1 << 2)
337 :
338 0 : static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
339 : {
340 0 : struct bt_tags_iter_data *iter_data = data;
341 0 : struct blk_mq_tags *tags = iter_data->tags;
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 (!(iter_data->flags & BT_TAG_ITER_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);
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, void *data)
453 : {
454 0 : unsigned *count = data;
455 :
456 0 : if (blk_mq_request_completed(rq))
457 0 : (*count)++;
458 0 : return true;
459 : }
460 :
461 : /**
462 : * blk_mq_tagset_wait_completed_request - Wait until all scheduled request
463 : * completions have finished.
464 : * @tagset: Tag set to drain completed request
465 : *
466 : * Note: This function has to be run after all IO queues are shutdown
467 : */
468 0 : void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset)
469 : {
470 0 : while (true) {
471 0 : unsigned count = 0;
472 :
473 0 : blk_mq_tagset_busy_iter(tagset,
474 : blk_mq_tagset_count_completed_rqs, &count);
475 0 : if (!count)
476 : break;
477 0 : msleep(5);
478 : }
479 0 : }
480 : EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
481 :
482 : /**
483 : * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag
484 : * @q: Request queue to examine.
485 : * @fn: Pointer to the function that will be called for each request
486 : * on @q. @fn will be called as follows: @fn(hctx, rq, @priv,
487 : * reserved) where rq is a pointer to a request and hctx points
488 : * to the hardware queue associated with the request. 'reserved'
489 : * indicates whether or not @rq is a reserved request.
490 : * @priv: Will be passed as third argument to @fn.
491 : *
492 : * Note: if @q->tag_set is shared with other request queues then @fn will be
493 : * called for all requests on all queues that share that tag set and not only
494 : * for requests associated with @q.
495 : */
496 0 : void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn,
497 : void *priv)
498 : {
499 : /*
500 : * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and hctx_table
501 : * while the queue is frozen. So we can use q_usage_counter to avoid
502 : * racing with it.
503 : */
504 0 : if (!percpu_ref_tryget(&q->q_usage_counter))
505 : return;
506 :
507 0 : if (blk_mq_is_shared_tags(q->tag_set->flags)) {
508 0 : struct blk_mq_tags *tags = q->tag_set->shared_tags;
509 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
510 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
511 :
512 0 : if (tags->nr_reserved_tags)
513 : bt_for_each(NULL, q, bresv, fn, priv, true);
514 : bt_for_each(NULL, q, btags, fn, priv, false);
515 : } else {
516 : struct blk_mq_hw_ctx *hctx;
517 : unsigned long i;
518 :
519 0 : queue_for_each_hw_ctx(q, hctx, i) {
520 0 : struct blk_mq_tags *tags = hctx->tags;
521 0 : struct sbitmap_queue *bresv = &tags->breserved_tags;
522 0 : struct sbitmap_queue *btags = &tags->bitmap_tags;
523 :
524 : /*
525 : * If no software queues are currently mapped to this
526 : * hardware queue, there's nothing to check
527 : */
528 0 : if (!blk_mq_hw_queue_mapped(hctx))
529 0 : continue;
530 :
531 0 : if (tags->nr_reserved_tags)
532 : bt_for_each(hctx, q, bresv, fn, priv, true);
533 : bt_for_each(hctx, q, btags, fn, priv, false);
534 : }
535 : }
536 0 : blk_queue_exit(q);
537 : }
538 :
539 : static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
540 : bool round_robin, int node)
541 : {
542 0 : return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
543 : node);
544 : }
545 :
546 0 : int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags,
547 : struct sbitmap_queue *breserved_tags,
548 : unsigned int queue_depth, unsigned int reserved,
549 : int node, int alloc_policy)
550 : {
551 0 : unsigned int depth = queue_depth - reserved;
552 0 : bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
553 :
554 0 : if (bt_alloc(bitmap_tags, depth, round_robin, node))
555 : return -ENOMEM;
556 0 : if (bt_alloc(breserved_tags, reserved, round_robin, node))
557 : goto free_bitmap_tags;
558 :
559 : return 0;
560 :
561 : free_bitmap_tags:
562 0 : sbitmap_queue_free(bitmap_tags);
563 0 : return -ENOMEM;
564 : }
565 :
566 0 : struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
567 : unsigned int reserved_tags,
568 : int node, int alloc_policy)
569 : {
570 : struct blk_mq_tags *tags;
571 :
572 0 : if (total_tags > BLK_MQ_TAG_MAX) {
573 0 : pr_err("blk-mq: tag depth too large\n");
574 0 : return NULL;
575 : }
576 :
577 0 : tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
578 0 : if (!tags)
579 : return NULL;
580 :
581 0 : tags->nr_tags = total_tags;
582 0 : tags->nr_reserved_tags = reserved_tags;
583 0 : spin_lock_init(&tags->lock);
584 :
585 0 : if (blk_mq_init_bitmaps(&tags->bitmap_tags, &tags->breserved_tags,
586 : total_tags, reserved_tags, node,
587 : alloc_policy) < 0) {
588 0 : kfree(tags);
589 0 : return NULL;
590 : }
591 : return tags;
592 : }
593 :
594 0 : void blk_mq_free_tags(struct blk_mq_tags *tags)
595 : {
596 0 : sbitmap_queue_free(&tags->bitmap_tags);
597 0 : sbitmap_queue_free(&tags->breserved_tags);
598 0 : kfree(tags);
599 0 : }
600 :
601 0 : int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
602 : struct blk_mq_tags **tagsptr, unsigned int tdepth,
603 : bool can_grow)
604 : {
605 0 : struct blk_mq_tags *tags = *tagsptr;
606 :
607 0 : if (tdepth <= tags->nr_reserved_tags)
608 : return -EINVAL;
609 :
610 : /*
611 : * If we are allowed to grow beyond the original size, allocate
612 : * a new set of tags before freeing the old one.
613 : */
614 0 : if (tdepth > tags->nr_tags) {
615 0 : struct blk_mq_tag_set *set = hctx->queue->tag_set;
616 : struct blk_mq_tags *new;
617 :
618 0 : if (!can_grow)
619 : return -EINVAL;
620 :
621 : /*
622 : * We need some sort of upper limit, set it high enough that
623 : * no valid use cases should require more.
624 : */
625 0 : if (tdepth > MAX_SCHED_RQ)
626 : return -EINVAL;
627 :
628 : /*
629 : * Only the sbitmap needs resizing since we allocated the max
630 : * initially.
631 : */
632 0 : if (blk_mq_is_shared_tags(set->flags))
633 : return 0;
634 :
635 0 : new = blk_mq_alloc_map_and_rqs(set, hctx->queue_num, tdepth);
636 0 : if (!new)
637 : return -ENOMEM;
638 :
639 0 : blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num);
640 0 : *tagsptr = new;
641 : } else {
642 : /*
643 : * Don't need (or can't) update reserved tags here, they
644 : * remain static and should never need resizing.
645 : */
646 0 : sbitmap_queue_resize(&tags->bitmap_tags,
647 : tdepth - tags->nr_reserved_tags);
648 : }
649 :
650 : return 0;
651 : }
652 :
653 0 : void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size)
654 : {
655 0 : struct blk_mq_tags *tags = set->shared_tags;
656 :
657 0 : sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags);
658 0 : }
659 :
660 0 : void blk_mq_tag_update_sched_shared_tags(struct request_queue *q)
661 : {
662 0 : sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags,
663 0 : q->nr_requests - q->tag_set->reserved_tags);
664 0 : }
665 :
666 : /**
667 : * blk_mq_unique_tag() - return a tag that is unique queue-wide
668 : * @rq: request for which to compute a unique tag
669 : *
670 : * The tag field in struct request is unique per hardware queue but not over
671 : * all hardware queues. Hence this function that returns a tag with the
672 : * hardware context index in the upper bits and the per hardware queue tag in
673 : * the lower bits.
674 : *
675 : * Note: When called for a request that is queued on a non-multiqueue request
676 : * queue, the hardware context index is set to zero.
677 : */
678 0 : u32 blk_mq_unique_tag(struct request *rq)
679 : {
680 0 : return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
681 0 : (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
682 : }
683 : EXPORT_SYMBOL(blk_mq_unique_tag);
|
