blob: 6714507aa6c75b716d34a53c708952bf5d0ae619 [file] [log] [blame]
Jens Axboe75bb4622014-05-28 10:15:41 -06001/*
Omar Sandoval88459642016-09-17 08:38:44 -06002 * Tag allocation using scalable bitmaps. Uses active queue tracking to support
3 * fairer distribution of tags between multiple submitters when a shared tag map
4 * is used.
Jens Axboe75bb4622014-05-28 10:15:41 -06005 *
6 * Copyright (C) 2013-2014 Jens Axboe
7 */
Jens Axboe320ae512013-10-24 09:20:05 +01008#include <linux/kernel.h>
9#include <linux/module.h>
Jens Axboe320ae512013-10-24 09:20:05 +010010
11#include <linux/blk-mq.h>
12#include "blk.h"
13#include "blk-mq.h"
14#include "blk-mq-tag.h"
15
Jens Axboe320ae512013-10-24 09:20:05 +010016bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
17{
Jens Axboe4bb659b2014-05-09 09:36:49 -060018 if (!tags)
19 return true;
20
Omar Sandoval88459642016-09-17 08:38:44 -060021 return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
Jens Axboe0d2602c2014-05-13 15:10:52 -060022}
23
24/*
25 * If a previously inactive queue goes active, bump the active user count.
26 */
27bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
28{
29 if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
30 !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
31 atomic_inc(&hctx->tags->active_queues);
32
33 return true;
34}
35
36/*
Jens Axboeaed3ea92014-12-22 14:04:42 -070037 * Wakeup all potentially sleeping on tags
Jens Axboe0d2602c2014-05-13 15:10:52 -060038 */
Jens Axboeaed3ea92014-12-22 14:04:42 -070039void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
Jens Axboe0d2602c2014-05-13 15:10:52 -060040{
Omar Sandoval88459642016-09-17 08:38:44 -060041 sbitmap_queue_wake_all(&tags->bitmap_tags);
42 if (include_reserve)
43 sbitmap_queue_wake_all(&tags->breserved_tags);
Jens Axboe0d2602c2014-05-13 15:10:52 -060044}
45
46/*
Jens Axboee3a2b3f2014-05-20 11:49:02 -060047 * If a previously busy queue goes inactive, potential waiters could now
48 * be allowed to queue. Wake them up and check.
49 */
50void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
51{
52 struct blk_mq_tags *tags = hctx->tags;
53
54 if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
55 return;
56
57 atomic_dec(&tags->active_queues);
58
Jens Axboeaed3ea92014-12-22 14:04:42 -070059 blk_mq_tag_wakeup_all(tags, false);
Jens Axboee3a2b3f2014-05-20 11:49:02 -060060}
61
62/*
Jens Axboe0d2602c2014-05-13 15:10:52 -060063 * For shared tag users, we track the number of currently active users
64 * and attempt to provide a fair share of the tag depth for each of them.
65 */
66static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
Omar Sandoval88459642016-09-17 08:38:44 -060067 struct sbitmap_queue *bt)
Jens Axboe0d2602c2014-05-13 15:10:52 -060068{
69 unsigned int depth, users;
70
71 if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
72 return true;
73 if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
74 return true;
75
76 /*
77 * Don't try dividing an ant
78 */
Omar Sandoval88459642016-09-17 08:38:44 -060079 if (bt->sb.depth == 1)
Jens Axboe0d2602c2014-05-13 15:10:52 -060080 return true;
81
82 users = atomic_read(&hctx->tags->active_queues);
83 if (!users)
84 return true;
85
86 /*
87 * Allow at least some tags
88 */
Omar Sandoval88459642016-09-17 08:38:44 -060089 depth = max((bt->sb.depth + users - 1) / users, 4U);
Jens Axboe0d2602c2014-05-13 15:10:52 -060090 return atomic_read(&hctx->nr_active) < depth;
91}
92
Jens Axboe200e86b2017-01-25 08:11:38 -070093static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
94 struct sbitmap_queue *bt)
Jens Axboe4bb659b2014-05-09 09:36:49 -060095{
Jens Axboe200e86b2017-01-25 08:11:38 -070096 if (!(data->flags & BLK_MQ_REQ_INTERNAL) &&
97 !hctx_may_queue(data->hctx, bt))
Jens Axboe0d2602c2014-05-13 15:10:52 -060098 return -1;
Omar Sandoval229a92872017-04-14 00:59:59 -070099 if (data->shallow_depth)
100 return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
101 else
102 return __sbitmap_queue_get(bt);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600103}
104
Jens Axboe49411152017-01-13 08:09:05 -0700105unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
Jens Axboe4bb659b2014-05-09 09:36:49 -0600106{
Jens Axboe49411152017-01-13 08:09:05 -0700107 struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
108 struct sbitmap_queue *bt;
Omar Sandoval88459642016-09-17 08:38:44 -0600109 struct sbq_wait_state *ws;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600110 DEFINE_WAIT(wait);
Jens Axboe49411152017-01-13 08:09:05 -0700111 unsigned int tag_offset;
Jens Axboebd6737f2017-01-27 01:00:47 -0700112 bool drop_ctx;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600113 int tag;
114
Jens Axboe49411152017-01-13 08:09:05 -0700115 if (data->flags & BLK_MQ_REQ_RESERVED) {
116 if (unlikely(!tags->nr_reserved_tags)) {
117 WARN_ON_ONCE(1);
118 return BLK_MQ_TAG_FAIL;
119 }
120 bt = &tags->breserved_tags;
121 tag_offset = 0;
122 } else {
123 bt = &tags->bitmap_tags;
124 tag_offset = tags->nr_reserved_tags;
125 }
126
Jens Axboe200e86b2017-01-25 08:11:38 -0700127 tag = __blk_mq_get_tag(data, bt);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600128 if (tag != -1)
Jens Axboe49411152017-01-13 08:09:05 -0700129 goto found_tag;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600130
Christoph Hellwig6f3b0e82015-11-26 09:13:05 +0100131 if (data->flags & BLK_MQ_REQ_NOWAIT)
Jens Axboe49411152017-01-13 08:09:05 -0700132 return BLK_MQ_TAG_FAIL;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600133
Jens Axboe49411152017-01-13 08:09:05 -0700134 ws = bt_wait_ptr(bt, data->hctx);
Jens Axboebd6737f2017-01-27 01:00:47 -0700135 drop_ctx = data->ctx == NULL;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600136 do {
Omar Sandoval88459642016-09-17 08:38:44 -0600137 prepare_to_wait(&ws->wait, &wait, TASK_UNINTERRUPTIBLE);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600138
Jens Axboe200e86b2017-01-25 08:11:38 -0700139 tag = __blk_mq_get_tag(data, bt);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600140 if (tag != -1)
141 break;
142
Bart Van Asscheb3223202014-12-08 08:46:34 -0700143 /*
144 * We're out of tags on this hardware queue, kick any
145 * pending IO submits before going to sleep waiting for
Jens Axboe8cecb072017-01-19 07:39:17 -0700146 * some to complete.
Bart Van Asscheb3223202014-12-08 08:46:34 -0700147 */
Jens Axboe8cecb072017-01-19 07:39:17 -0700148 blk_mq_run_hw_queue(data->hctx, false);
Bart Van Asscheb3223202014-12-08 08:46:34 -0700149
Jens Axboe080ff352014-12-08 08:49:06 -0700150 /*
151 * Retry tag allocation after running the hardware queue,
152 * as running the queue may also have found completions.
153 */
Jens Axboe200e86b2017-01-25 08:11:38 -0700154 tag = __blk_mq_get_tag(data, bt);
Jens Axboe080ff352014-12-08 08:49:06 -0700155 if (tag != -1)
156 break;
157
Jens Axboebd6737f2017-01-27 01:00:47 -0700158 if (data->ctx)
159 blk_mq_put_ctx(data->ctx);
Ming Leicb96a42c2014-06-01 00:43:37 +0800160
Jens Axboe4bb659b2014-05-09 09:36:49 -0600161 io_schedule();
Ming Leicb96a42c2014-06-01 00:43:37 +0800162
163 data->ctx = blk_mq_get_ctx(data->q);
Christoph Hellwig7d7e0f92016-09-14 16:18:54 +0200164 data->hctx = blk_mq_map_queue(data->q, data->ctx->cpu);
Jens Axboe49411152017-01-13 08:09:05 -0700165 tags = blk_mq_tags_from_data(data);
166 if (data->flags & BLK_MQ_REQ_RESERVED)
167 bt = &tags->breserved_tags;
168 else
169 bt = &tags->bitmap_tags;
170
Omar Sandoval88459642016-09-17 08:38:44 -0600171 finish_wait(&ws->wait, &wait);
Jens Axboe49411152017-01-13 08:09:05 -0700172 ws = bt_wait_ptr(bt, data->hctx);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600173 } while (1);
174
Jens Axboebd6737f2017-01-27 01:00:47 -0700175 if (drop_ctx && data->ctx)
176 blk_mq_put_ctx(data->ctx);
177
Omar Sandoval88459642016-09-17 08:38:44 -0600178 finish_wait(&ws->wait, &wait);
Jens Axboe49411152017-01-13 08:09:05 -0700179
180found_tag:
181 return tag + tag_offset;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600182}
183
Jens Axboe49411152017-01-13 08:09:05 -0700184void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
185 struct blk_mq_ctx *ctx, unsigned int tag)
Jens Axboe320ae512013-10-24 09:20:05 +0100186{
Sagi Grimberg415b8062017-02-27 10:04:39 -0700187 if (!blk_mq_tag_is_reserved(tags, tag)) {
Jens Axboe4bb659b2014-05-09 09:36:49 -0600188 const int real_tag = tag - tags->nr_reserved_tags;
189
Jens Axboe70114c32014-11-24 15:52:30 -0700190 BUG_ON(real_tag >= tags->nr_tags);
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700191 sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
Jens Axboe70114c32014-11-24 15:52:30 -0700192 } else {
193 BUG_ON(tag >= tags->nr_reserved_tags);
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700194 sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
Jens Axboe70114c32014-11-24 15:52:30 -0700195 }
Jens Axboe320ae512013-10-24 09:20:05 +0100196}
197
Omar Sandoval88459642016-09-17 08:38:44 -0600198struct bt_iter_data {
199 struct blk_mq_hw_ctx *hctx;
200 busy_iter_fn *fn;
201 void *data;
202 bool reserved;
203};
204
205static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
Jens Axboe320ae512013-10-24 09:20:05 +0100206{
Omar Sandoval88459642016-09-17 08:38:44 -0600207 struct bt_iter_data *iter_data = data;
208 struct blk_mq_hw_ctx *hctx = iter_data->hctx;
209 struct blk_mq_tags *tags = hctx->tags;
210 bool reserved = iter_data->reserved;
Christoph Hellwig81481eb2014-09-13 16:40:11 -0700211 struct request *rq;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600212
Omar Sandoval88459642016-09-17 08:38:44 -0600213 if (!reserved)
214 bitnr += tags->nr_reserved_tags;
215 rq = tags->rqs[bitnr];
Jens Axboe4bb659b2014-05-09 09:36:49 -0600216
Jens Axboe7f5562d2017-08-04 13:37:03 -0600217 /*
218 * We can hit rq == NULL here, because the tagging functions
219 * test and set the bit before assining ->rqs[].
220 */
221 if (rq && rq->q == hctx->queue)
Omar Sandoval88459642016-09-17 08:38:44 -0600222 iter_data->fn(hctx, rq, iter_data->data, reserved);
223 return true;
Jens Axboe320ae512013-10-24 09:20:05 +0100224}
225
Omar Sandoval88459642016-09-17 08:38:44 -0600226static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
227 busy_iter_fn *fn, void *data, bool reserved)
Keith Buschf26cdc82015-06-01 09:29:53 -0600228{
Omar Sandoval88459642016-09-17 08:38:44 -0600229 struct bt_iter_data iter_data = {
230 .hctx = hctx,
231 .fn = fn,
232 .data = data,
233 .reserved = reserved,
234 };
235
236 sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
237}
238
239struct bt_tags_iter_data {
240 struct blk_mq_tags *tags;
241 busy_tag_iter_fn *fn;
242 void *data;
243 bool reserved;
244};
245
246static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
247{
248 struct bt_tags_iter_data *iter_data = data;
249 struct blk_mq_tags *tags = iter_data->tags;
250 bool reserved = iter_data->reserved;
Keith Buschf26cdc82015-06-01 09:29:53 -0600251 struct request *rq;
Keith Buschf26cdc82015-06-01 09:29:53 -0600252
Omar Sandoval88459642016-09-17 08:38:44 -0600253 if (!reserved)
254 bitnr += tags->nr_reserved_tags;
Keith Buschf26cdc82015-06-01 09:29:53 -0600255
Jens Axboe7f5562d2017-08-04 13:37:03 -0600256 /*
257 * We can hit rq == NULL here, because the tagging functions
258 * test and set the bit before assining ->rqs[].
259 */
260 rq = tags->rqs[bitnr];
261 if (rq)
262 iter_data->fn(rq, iter_data->data, reserved);
263
Omar Sandoval88459642016-09-17 08:38:44 -0600264 return true;
265}
Keith Buschf26cdc82015-06-01 09:29:53 -0600266
Omar Sandoval88459642016-09-17 08:38:44 -0600267static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
268 busy_tag_iter_fn *fn, void *data, bool reserved)
269{
270 struct bt_tags_iter_data iter_data = {
271 .tags = tags,
272 .fn = fn,
273 .data = data,
274 .reserved = reserved,
275 };
276
277 if (tags->rqs)
278 sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
Keith Buschf26cdc82015-06-01 09:29:53 -0600279}
280
Sagi Grimberge8f1e162016-03-10 13:58:49 +0200281static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
282 busy_tag_iter_fn *fn, void *priv)
Keith Buschf26cdc82015-06-01 09:29:53 -0600283{
284 if (tags->nr_reserved_tags)
Omar Sandoval88459642016-09-17 08:38:44 -0600285 bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
286 bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
Keith Buschf26cdc82015-06-01 09:29:53 -0600287}
Keith Buschf26cdc82015-06-01 09:29:53 -0600288
Sagi Grimberge0489482016-03-10 13:58:46 +0200289void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
290 busy_tag_iter_fn *fn, void *priv)
291{
292 int i;
293
294 for (i = 0; i < tagset->nr_hw_queues; i++) {
295 if (tagset->tags && tagset->tags[i])
296 blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv);
297 }
298}
299EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
300
Bart Van Assched352ae22017-08-17 16:23:03 -0700301int blk_mq_reinit_tagset(struct blk_mq_tag_set *set,
302 int (reinit_request)(void *, struct request *))
Sagi Grimberg486cf982016-07-06 21:55:48 +0900303{
304 int i, j, ret = 0;
305
Bart Van Assched352ae22017-08-17 16:23:03 -0700306 if (WARN_ON_ONCE(!reinit_request))
Sagi Grimberg486cf982016-07-06 21:55:48 +0900307 goto out;
308
309 for (i = 0; i < set->nr_hw_queues; i++) {
310 struct blk_mq_tags *tags = set->tags[i];
311
Sagi Grimberg0067d4b2017-03-13 16:10:11 +0200312 if (!tags)
313 continue;
314
Sagi Grimberg486cf982016-07-06 21:55:48 +0900315 for (j = 0; j < tags->nr_tags; j++) {
Jens Axboe2af8cbe2017-01-13 14:39:30 -0700316 if (!tags->static_rqs[j])
Sagi Grimberg486cf982016-07-06 21:55:48 +0900317 continue;
318
Bart Van Assched352ae22017-08-17 16:23:03 -0700319 ret = reinit_request(set->driver_data,
320 tags->static_rqs[j]);
Sagi Grimberg486cf982016-07-06 21:55:48 +0900321 if (ret)
322 goto out;
323 }
324 }
325
326out:
327 return ret;
328}
329EXPORT_SYMBOL_GPL(blk_mq_reinit_tagset);
330
Christoph Hellwig0bf6cd52015-09-27 21:01:51 +0200331void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
Christoph Hellwig81481eb2014-09-13 16:40:11 -0700332 void *priv)
Jens Axboe320ae512013-10-24 09:20:05 +0100333{
Christoph Hellwig0bf6cd52015-09-27 21:01:51 +0200334 struct blk_mq_hw_ctx *hctx;
335 int i;
Jens Axboe320ae512013-10-24 09:20:05 +0100336
Christoph Hellwig0bf6cd52015-09-27 21:01:51 +0200337
338 queue_for_each_hw_ctx(q, hctx, i) {
339 struct blk_mq_tags *tags = hctx->tags;
340
341 /*
342 * If not software queues are currently mapped to this
343 * hardware queue, there's nothing to check
344 */
345 if (!blk_mq_hw_queue_mapped(hctx))
346 continue;
347
348 if (tags->nr_reserved_tags)
Omar Sandoval88459642016-09-17 08:38:44 -0600349 bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
350 bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
Christoph Hellwig0bf6cd52015-09-27 21:01:51 +0200351 }
352
Jens Axboe320ae512013-10-24 09:20:05 +0100353}
354
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700355static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
356 bool round_robin, int node)
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600357{
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700358 return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
359 node);
Jens Axboe4bb659b2014-05-09 09:36:49 -0600360}
361
362static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
Shaohua Li24391c02015-01-23 14:18:00 -0700363 int node, int alloc_policy)
Jens Axboe4bb659b2014-05-09 09:36:49 -0600364{
365 unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700366 bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600367
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700368 if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node))
Omar Sandoval88459642016-09-17 08:38:44 -0600369 goto free_tags;
Omar Sandovalf4a644d2016-09-17 01:28:24 -0700370 if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin,
371 node))
Omar Sandoval88459642016-09-17 08:38:44 -0600372 goto free_bitmap_tags;
Jens Axboe4bb659b2014-05-09 09:36:49 -0600373
374 return tags;
Omar Sandoval88459642016-09-17 08:38:44 -0600375free_bitmap_tags:
376 sbitmap_queue_free(&tags->bitmap_tags);
377free_tags:
Jens Axboe4bb659b2014-05-09 09:36:49 -0600378 kfree(tags);
379 return NULL;
380}
381
Jens Axboe320ae512013-10-24 09:20:05 +0100382struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
Shaohua Li24391c02015-01-23 14:18:00 -0700383 unsigned int reserved_tags,
384 int node, int alloc_policy)
Jens Axboe320ae512013-10-24 09:20:05 +0100385{
Jens Axboe320ae512013-10-24 09:20:05 +0100386 struct blk_mq_tags *tags;
Jens Axboe320ae512013-10-24 09:20:05 +0100387
388 if (total_tags > BLK_MQ_TAG_MAX) {
389 pr_err("blk-mq: tag depth too large\n");
390 return NULL;
391 }
392
393 tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
394 if (!tags)
395 return NULL;
396
Jens Axboe320ae512013-10-24 09:20:05 +0100397 tags->nr_tags = total_tags;
398 tags->nr_reserved_tags = reserved_tags;
Jens Axboe320ae512013-10-24 09:20:05 +0100399
Shaohua Li24391c02015-01-23 14:18:00 -0700400 return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
Jens Axboe320ae512013-10-24 09:20:05 +0100401}
402
403void blk_mq_free_tags(struct blk_mq_tags *tags)
404{
Omar Sandoval88459642016-09-17 08:38:44 -0600405 sbitmap_queue_free(&tags->bitmap_tags);
406 sbitmap_queue_free(&tags->breserved_tags);
Jens Axboe320ae512013-10-24 09:20:05 +0100407 kfree(tags);
408}
409
Jens Axboe70f36b62017-01-19 10:59:07 -0700410int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
411 struct blk_mq_tags **tagsptr, unsigned int tdepth,
412 bool can_grow)
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600413{
Jens Axboe70f36b62017-01-19 10:59:07 -0700414 struct blk_mq_tags *tags = *tagsptr;
415
416 if (tdepth <= tags->nr_reserved_tags)
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600417 return -EINVAL;
418
Jens Axboe70f36b62017-01-19 10:59:07 -0700419 tdepth -= tags->nr_reserved_tags;
Omar Sandoval88459642016-09-17 08:38:44 -0600420
Jens Axboe70f36b62017-01-19 10:59:07 -0700421 /*
422 * If we are allowed to grow beyond the original size, allocate
423 * a new set of tags before freeing the old one.
424 */
425 if (tdepth > tags->nr_tags) {
426 struct blk_mq_tag_set *set = hctx->queue->tag_set;
427 struct blk_mq_tags *new;
428 bool ret;
429
430 if (!can_grow)
431 return -EINVAL;
432
433 /*
434 * We need some sort of upper limit, set it high enough that
435 * no valid use cases should require more.
436 */
437 if (tdepth > 16 * BLKDEV_MAX_RQ)
438 return -EINVAL;
439
440 new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, 0);
441 if (!new)
442 return -ENOMEM;
443 ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
444 if (ret) {
445 blk_mq_free_rq_map(new);
446 return -ENOMEM;
447 }
448
449 blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
450 blk_mq_free_rq_map(*tagsptr);
451 *tagsptr = new;
452 } else {
453 /*
454 * Don't need (or can't) update reserved tags here, they
455 * remain static and should never need resizing.
456 */
457 sbitmap_queue_resize(&tags->bitmap_tags, tdepth);
458 }
459
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600460 return 0;
461}
462
Bart Van Assche205fb5f52014-10-30 14:45:11 +0100463/**
464 * blk_mq_unique_tag() - return a tag that is unique queue-wide
465 * @rq: request for which to compute a unique tag
466 *
467 * The tag field in struct request is unique per hardware queue but not over
468 * all hardware queues. Hence this function that returns a tag with the
469 * hardware context index in the upper bits and the per hardware queue tag in
470 * the lower bits.
471 *
472 * Note: When called for a request that is queued on a non-multiqueue request
473 * queue, the hardware context index is set to zero.
474 */
475u32 blk_mq_unique_tag(struct request *rq)
476{
477 struct request_queue *q = rq->q;
478 struct blk_mq_hw_ctx *hctx;
479 int hwq = 0;
480
481 if (q->mq_ops) {
Christoph Hellwig7d7e0f92016-09-14 16:18:54 +0200482 hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu);
Bart Van Assche205fb5f52014-10-30 14:45:11 +0100483 hwq = hctx->queue_num;
484 }
485
486 return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
487 (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
488}
489EXPORT_SYMBOL(blk_mq_unique_tag);