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3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
75bb4625 | 2 | /* |
88459642 OS |
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. | |
75bb4625 JA |
6 | * |
7 | * Copyright (C) 2013-2014 Jens Axboe | |
8 | */ | |
320ae51f JA |
9 | #include <linux/kernel.h> |
10 | #include <linux/module.h> | |
320ae51f JA |
11 | |
12 | #include <linux/blk-mq.h> | |
13 | #include "blk.h" | |
14 | #include "blk-mq.h" | |
15 | #include "blk-mq-tag.h" | |
16 | ||
320ae51f JA |
17 | bool blk_mq_has_free_tags(struct blk_mq_tags *tags) |
18 | { | |
4bb659b1 JA |
19 | if (!tags) |
20 | return true; | |
21 | ||
88459642 | 22 | return sbitmap_any_bit_clear(&tags->bitmap_tags.sb); |
0d2602ca JA |
23 | } |
24 | ||
25 | /* | |
26 | * If a previously inactive queue goes active, bump the active user count. | |
d263ed99 JW |
27 | * We need to do this before try to allocate driver tag, then even if fail |
28 | * to get tag when first time, the other shared-tag users could reserve | |
29 | * budget for it. | |
0d2602ca JA |
30 | */ |
31 | bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) | |
32 | { | |
33 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) && | |
34 | !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
35 | atomic_inc(&hctx->tags->active_queues); | |
36 | ||
37 | return true; | |
38 | } | |
39 | ||
40 | /* | |
aed3ea94 | 41 | * Wakeup all potentially sleeping on tags |
0d2602ca | 42 | */ |
aed3ea94 | 43 | void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve) |
0d2602ca | 44 | { |
88459642 OS |
45 | sbitmap_queue_wake_all(&tags->bitmap_tags); |
46 | if (include_reserve) | |
47 | sbitmap_queue_wake_all(&tags->breserved_tags); | |
0d2602ca JA |
48 | } |
49 | ||
e3a2b3f9 JA |
50 | /* |
51 | * If a previously busy queue goes inactive, potential waiters could now | |
52 | * be allowed to queue. Wake them up and check. | |
53 | */ | |
54 | void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) | |
55 | { | |
56 | struct blk_mq_tags *tags = hctx->tags; | |
57 | ||
58 | if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
59 | return; | |
60 | ||
61 | atomic_dec(&tags->active_queues); | |
62 | ||
aed3ea94 | 63 | blk_mq_tag_wakeup_all(tags, false); |
e3a2b3f9 JA |
64 | } |
65 | ||
0d2602ca JA |
66 | /* |
67 | * For shared tag users, we track the number of currently active users | |
68 | * and attempt to provide a fair share of the tag depth for each of them. | |
69 | */ | |
70 | static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, | |
88459642 | 71 | struct sbitmap_queue *bt) |
0d2602ca JA |
72 | { |
73 | unsigned int depth, users; | |
74 | ||
75 | if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED)) | |
76 | return true; | |
77 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
78 | return true; | |
79 | ||
80 | /* | |
81 | * Don't try dividing an ant | |
82 | */ | |
88459642 | 83 | if (bt->sb.depth == 1) |
0d2602ca JA |
84 | return true; |
85 | ||
86 | users = atomic_read(&hctx->tags->active_queues); | |
87 | if (!users) | |
88 | return true; | |
89 | ||
90 | /* | |
91 | * Allow at least some tags | |
92 | */ | |
88459642 | 93 | depth = max((bt->sb.depth + users - 1) / users, 4U); |
0d2602ca JA |
94 | return atomic_read(&hctx->nr_active) < depth; |
95 | } | |
96 | ||
200e86b3 JA |
97 | static int __blk_mq_get_tag(struct blk_mq_alloc_data *data, |
98 | struct sbitmap_queue *bt) | |
4bb659b1 | 99 | { |
200e86b3 JA |
100 | if (!(data->flags & BLK_MQ_REQ_INTERNAL) && |
101 | !hctx_may_queue(data->hctx, bt)) | |
0d2602ca | 102 | return -1; |
229a9287 OS |
103 | if (data->shallow_depth) |
104 | return __sbitmap_queue_get_shallow(bt, data->shallow_depth); | |
105 | else | |
106 | return __sbitmap_queue_get(bt); | |
4bb659b1 JA |
107 | } |
108 | ||
4941115b | 109 | unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) |
320ae51f | 110 | { |
4941115b JA |
111 | struct blk_mq_tags *tags = blk_mq_tags_from_data(data); |
112 | struct sbitmap_queue *bt; | |
88459642 | 113 | struct sbq_wait_state *ws; |
5d2ee712 | 114 | DEFINE_SBQ_WAIT(wait); |
4941115b | 115 | unsigned int tag_offset; |
bd6737f1 | 116 | bool drop_ctx; |
320ae51f JA |
117 | int tag; |
118 | ||
4941115b JA |
119 | if (data->flags & BLK_MQ_REQ_RESERVED) { |
120 | if (unlikely(!tags->nr_reserved_tags)) { | |
121 | WARN_ON_ONCE(1); | |
122 | return BLK_MQ_TAG_FAIL; | |
123 | } | |
124 | bt = &tags->breserved_tags; | |
125 | tag_offset = 0; | |
126 | } else { | |
127 | bt = &tags->bitmap_tags; | |
128 | tag_offset = tags->nr_reserved_tags; | |
129 | } | |
130 | ||
200e86b3 | 131 | tag = __blk_mq_get_tag(data, bt); |
4bb659b1 | 132 | if (tag != -1) |
4941115b | 133 | goto found_tag; |
4bb659b1 | 134 | |
6f3b0e8b | 135 | if (data->flags & BLK_MQ_REQ_NOWAIT) |
4941115b | 136 | return BLK_MQ_TAG_FAIL; |
4bb659b1 | 137 | |
4941115b | 138 | ws = bt_wait_ptr(bt, data->hctx); |
bd6737f1 | 139 | drop_ctx = data->ctx == NULL; |
4bb659b1 | 140 | do { |
e6fc4649 ML |
141 | struct sbitmap_queue *bt_prev; |
142 | ||
b3223207 BVA |
143 | /* |
144 | * We're out of tags on this hardware queue, kick any | |
145 | * pending IO submits before going to sleep waiting for | |
8cecb07d | 146 | * some to complete. |
b3223207 | 147 | */ |
8cecb07d | 148 | blk_mq_run_hw_queue(data->hctx, false); |
b3223207 | 149 | |
080ff351 JA |
150 | /* |
151 | * Retry tag allocation after running the hardware queue, | |
152 | * as running the queue may also have found completions. | |
153 | */ | |
200e86b3 | 154 | tag = __blk_mq_get_tag(data, bt); |
080ff351 JA |
155 | if (tag != -1) |
156 | break; | |
157 | ||
5d2ee712 | 158 | sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE); |
4e5dff41 JA |
159 | |
160 | tag = __blk_mq_get_tag(data, bt); | |
161 | if (tag != -1) | |
162 | break; | |
163 | ||
bd6737f1 JA |
164 | if (data->ctx) |
165 | blk_mq_put_ctx(data->ctx); | |
cb96a42c | 166 | |
e6fc4649 | 167 | bt_prev = bt; |
4bb659b1 | 168 | io_schedule(); |
cb96a42c | 169 | |
5d2ee712 JA |
170 | sbitmap_finish_wait(bt, ws, &wait); |
171 | ||
cb96a42c | 172 | data->ctx = blk_mq_get_ctx(data->q); |
f9afca4d | 173 | data->hctx = blk_mq_map_queue(data->q, data->cmd_flags, |
8ccdf4a3 | 174 | data->ctx); |
4941115b JA |
175 | tags = blk_mq_tags_from_data(data); |
176 | if (data->flags & BLK_MQ_REQ_RESERVED) | |
177 | bt = &tags->breserved_tags; | |
178 | else | |
179 | bt = &tags->bitmap_tags; | |
180 | ||
e6fc4649 ML |
181 | /* |
182 | * If destination hw queue is changed, fake wake up on | |
183 | * previous queue for compensating the wake up miss, so | |
184 | * other allocations on previous queue won't be starved. | |
185 | */ | |
186 | if (bt != bt_prev) | |
187 | sbitmap_queue_wake_up(bt_prev); | |
188 | ||
4941115b | 189 | ws = bt_wait_ptr(bt, data->hctx); |
4bb659b1 JA |
190 | } while (1); |
191 | ||
bd6737f1 JA |
192 | if (drop_ctx && data->ctx) |
193 | blk_mq_put_ctx(data->ctx); | |
194 | ||
5d2ee712 | 195 | sbitmap_finish_wait(bt, ws, &wait); |
320ae51f | 196 | |
4941115b JA |
197 | found_tag: |
198 | return tag + tag_offset; | |
320ae51f JA |
199 | } |
200 | ||
4941115b JA |
201 | void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags, |
202 | struct blk_mq_ctx *ctx, unsigned int tag) | |
320ae51f | 203 | { |
415b806d | 204 | if (!blk_mq_tag_is_reserved(tags, tag)) { |
4bb659b1 JA |
205 | const int real_tag = tag - tags->nr_reserved_tags; |
206 | ||
70114c39 | 207 | BUG_ON(real_tag >= tags->nr_tags); |
f4a644db | 208 | sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu); |
70114c39 JA |
209 | } else { |
210 | BUG_ON(tag >= tags->nr_reserved_tags); | |
f4a644db | 211 | sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu); |
70114c39 | 212 | } |
320ae51f JA |
213 | } |
214 | ||
88459642 OS |
215 | struct bt_iter_data { |
216 | struct blk_mq_hw_ctx *hctx; | |
217 | busy_iter_fn *fn; | |
218 | void *data; | |
219 | bool reserved; | |
220 | }; | |
221 | ||
222 | static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) | |
320ae51f | 223 | { |
88459642 OS |
224 | struct bt_iter_data *iter_data = data; |
225 | struct blk_mq_hw_ctx *hctx = iter_data->hctx; | |
226 | struct blk_mq_tags *tags = hctx->tags; | |
227 | bool reserved = iter_data->reserved; | |
81481eb4 | 228 | struct request *rq; |
4bb659b1 | 229 | |
88459642 OS |
230 | if (!reserved) |
231 | bitnr += tags->nr_reserved_tags; | |
232 | rq = tags->rqs[bitnr]; | |
4bb659b1 | 233 | |
7f5562d5 JA |
234 | /* |
235 | * We can hit rq == NULL here, because the tagging functions | |
c7b1bf5c | 236 | * test and set the bit before assigning ->rqs[]. |
7f5562d5 JA |
237 | */ |
238 | if (rq && rq->q == hctx->queue) | |
7baa8572 | 239 | return iter_data->fn(hctx, rq, iter_data->data, reserved); |
88459642 OS |
240 | return true; |
241 | } | |
4bb659b1 | 242 | |
c7b1bf5c BVA |
243 | /** |
244 | * bt_for_each - iterate over the requests associated with a hardware queue | |
245 | * @hctx: Hardware queue to examine. | |
246 | * @bt: sbitmap to examine. This is either the breserved_tags member | |
247 | * or the bitmap_tags member of struct blk_mq_tags. | |
248 | * @fn: Pointer to the function that will be called for each request | |
249 | * associated with @hctx that has been assigned a driver tag. | |
250 | * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved) | |
ab11fe5a JA |
251 | * where rq is a pointer to a request. Return true to continue |
252 | * iterating tags, false to stop. | |
c7b1bf5c BVA |
253 | * @data: Will be passed as third argument to @fn. |
254 | * @reserved: Indicates whether @bt is the breserved_tags member or the | |
255 | * bitmap_tags member of struct blk_mq_tags. | |
256 | */ | |
88459642 OS |
257 | static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt, |
258 | busy_iter_fn *fn, void *data, bool reserved) | |
259 | { | |
260 | struct bt_iter_data iter_data = { | |
261 | .hctx = hctx, | |
262 | .fn = fn, | |
263 | .data = data, | |
264 | .reserved = reserved, | |
265 | }; | |
266 | ||
267 | sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data); | |
320ae51f JA |
268 | } |
269 | ||
88459642 OS |
270 | struct bt_tags_iter_data { |
271 | struct blk_mq_tags *tags; | |
272 | busy_tag_iter_fn *fn; | |
273 | void *data; | |
274 | bool reserved; | |
275 | }; | |
276 | ||
277 | static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) | |
f26cdc85 | 278 | { |
88459642 OS |
279 | struct bt_tags_iter_data *iter_data = data; |
280 | struct blk_mq_tags *tags = iter_data->tags; | |
281 | bool reserved = iter_data->reserved; | |
f26cdc85 | 282 | struct request *rq; |
f26cdc85 | 283 | |
88459642 OS |
284 | if (!reserved) |
285 | bitnr += tags->nr_reserved_tags; | |
7f5562d5 JA |
286 | |
287 | /* | |
288 | * We can hit rq == NULL here, because the tagging functions | |
289 | * test and set the bit before assining ->rqs[]. | |
290 | */ | |
88459642 | 291 | rq = tags->rqs[bitnr]; |
2d5ba0e2 | 292 | if (rq && blk_mq_request_started(rq)) |
7baa8572 | 293 | return iter_data->fn(rq, iter_data->data, reserved); |
f26cdc85 | 294 | |
88459642 OS |
295 | return true; |
296 | } | |
297 | ||
c7b1bf5c BVA |
298 | /** |
299 | * bt_tags_for_each - iterate over the requests in a tag map | |
300 | * @tags: Tag map to iterate over. | |
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 started | |
304 | * request. @fn will be called as follows: @fn(rq, @data, | |
ab11fe5a JA |
305 | * @reserved) where rq is a pointer to a request. Return true |
306 | * to continue iterating tags, false to stop. | |
c7b1bf5c BVA |
307 | * @data: Will be passed as second 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 | */ | |
88459642 OS |
311 | static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt, |
312 | busy_tag_iter_fn *fn, void *data, bool reserved) | |
313 | { | |
314 | struct bt_tags_iter_data iter_data = { | |
315 | .tags = tags, | |
316 | .fn = fn, | |
317 | .data = data, | |
318 | .reserved = reserved, | |
319 | }; | |
320 | ||
321 | if (tags->rqs) | |
322 | sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data); | |
f26cdc85 KB |
323 | } |
324 | ||
c7b1bf5c BVA |
325 | /** |
326 | * blk_mq_all_tag_busy_iter - iterate over all started requests in a tag map | |
327 | * @tags: Tag map to iterate over. | |
328 | * @fn: Pointer to the function that will be called for each started | |
329 | * request. @fn will be called as follows: @fn(rq, @priv, | |
330 | * reserved) where rq is a pointer to a request. 'reserved' | |
ab11fe5a JA |
331 | * indicates whether or not @rq is a reserved request. Return |
332 | * true to continue iterating tags, false to stop. | |
c7b1bf5c BVA |
333 | * @priv: Will be passed as second argument to @fn. |
334 | */ | |
e8f1e163 SG |
335 | static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags, |
336 | busy_tag_iter_fn *fn, void *priv) | |
f26cdc85 KB |
337 | { |
338 | if (tags->nr_reserved_tags) | |
88459642 OS |
339 | bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true); |
340 | bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false); | |
f26cdc85 | 341 | } |
f26cdc85 | 342 | |
c7b1bf5c BVA |
343 | /** |
344 | * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set | |
345 | * @tagset: Tag set to iterate over. | |
346 | * @fn: Pointer to the function that will be called for each started | |
347 | * request. @fn will be called as follows: @fn(rq, @priv, | |
348 | * reserved) where rq is a pointer to a request. 'reserved' | |
ab11fe5a JA |
349 | * indicates whether or not @rq is a reserved request. Return |
350 | * true to continue iterating tags, false to stop. | |
c7b1bf5c BVA |
351 | * @priv: Will be passed as second argument to @fn. |
352 | */ | |
e0489487 SG |
353 | void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset, |
354 | busy_tag_iter_fn *fn, void *priv) | |
355 | { | |
356 | int i; | |
357 | ||
358 | for (i = 0; i < tagset->nr_hw_queues; i++) { | |
359 | if (tagset->tags && tagset->tags[i]) | |
360 | blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv); | |
361 | } | |
362 | } | |
363 | EXPORT_SYMBOL(blk_mq_tagset_busy_iter); | |
364 | ||
c7b1bf5c BVA |
365 | /** |
366 | * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag | |
367 | * @q: Request queue to examine. | |
368 | * @fn: Pointer to the function that will be called for each request | |
369 | * on @q. @fn will be called as follows: @fn(hctx, rq, @priv, | |
370 | * reserved) where rq is a pointer to a request and hctx points | |
371 | * to the hardware queue associated with the request. 'reserved' | |
372 | * indicates whether or not @rq is a reserved request. | |
373 | * @priv: Will be passed as third argument to @fn. | |
374 | * | |
375 | * Note: if @q->tag_set is shared with other request queues then @fn will be | |
376 | * called for all requests on all queues that share that tag set and not only | |
377 | * for requests associated with @q. | |
378 | */ | |
0bf6cd5b | 379 | void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn, |
81481eb4 | 380 | void *priv) |
320ae51f | 381 | { |
0bf6cd5b CH |
382 | struct blk_mq_hw_ctx *hctx; |
383 | int i; | |
384 | ||
f5bbbbe4 | 385 | /* |
c7b1bf5c BVA |
386 | * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and queue_hw_ctx |
387 | * while the queue is frozen. So we can use q_usage_counter to avoid | |
388 | * racing with it. __blk_mq_update_nr_hw_queues() uses | |
389 | * synchronize_rcu() to ensure this function left the critical section | |
390 | * below. | |
f5bbbbe4 | 391 | */ |
530ca2c9 | 392 | if (!percpu_ref_tryget(&q->q_usage_counter)) |
f5bbbbe4 | 393 | return; |
0bf6cd5b CH |
394 | |
395 | queue_for_each_hw_ctx(q, hctx, i) { | |
396 | struct blk_mq_tags *tags = hctx->tags; | |
397 | ||
398 | /* | |
c7b1bf5c | 399 | * If no software queues are currently mapped to this |
0bf6cd5b CH |
400 | * hardware queue, there's nothing to check |
401 | */ | |
402 | if (!blk_mq_hw_queue_mapped(hctx)) | |
403 | continue; | |
404 | ||
405 | if (tags->nr_reserved_tags) | |
88459642 OS |
406 | bt_for_each(hctx, &tags->breserved_tags, fn, priv, true); |
407 | bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false); | |
4bb659b1 | 408 | } |
530ca2c9 | 409 | blk_queue_exit(q); |
4bb659b1 JA |
410 | } |
411 | ||
f4a644db OS |
412 | static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth, |
413 | bool round_robin, int node) | |
4bb659b1 | 414 | { |
f4a644db OS |
415 | return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL, |
416 | node); | |
4bb659b1 JA |
417 | } |
418 | ||
419 | static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, | |
24391c0d | 420 | int node, int alloc_policy) |
4bb659b1 JA |
421 | { |
422 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; | |
f4a644db | 423 | bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR; |
4bb659b1 | 424 | |
f4a644db | 425 | if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node)) |
88459642 | 426 | goto free_tags; |
f4a644db OS |
427 | if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin, |
428 | node)) | |
88459642 | 429 | goto free_bitmap_tags; |
4bb659b1 JA |
430 | |
431 | return tags; | |
88459642 OS |
432 | free_bitmap_tags: |
433 | sbitmap_queue_free(&tags->bitmap_tags); | |
434 | free_tags: | |
4bb659b1 JA |
435 | kfree(tags); |
436 | return NULL; | |
437 | } | |
438 | ||
320ae51f | 439 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, |
24391c0d SL |
440 | unsigned int reserved_tags, |
441 | int node, int alloc_policy) | |
320ae51f | 442 | { |
320ae51f | 443 | struct blk_mq_tags *tags; |
320ae51f JA |
444 | |
445 | if (total_tags > BLK_MQ_TAG_MAX) { | |
446 | pr_err("blk-mq: tag depth too large\n"); | |
447 | return NULL; | |
448 | } | |
449 | ||
450 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); | |
451 | if (!tags) | |
452 | return NULL; | |
453 | ||
320ae51f JA |
454 | tags->nr_tags = total_tags; |
455 | tags->nr_reserved_tags = reserved_tags; | |
320ae51f | 456 | |
24391c0d | 457 | return blk_mq_init_bitmap_tags(tags, node, alloc_policy); |
320ae51f JA |
458 | } |
459 | ||
460 | void blk_mq_free_tags(struct blk_mq_tags *tags) | |
461 | { | |
88459642 OS |
462 | sbitmap_queue_free(&tags->bitmap_tags); |
463 | sbitmap_queue_free(&tags->breserved_tags); | |
320ae51f JA |
464 | kfree(tags); |
465 | } | |
466 | ||
70f36b60 JA |
467 | int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, |
468 | struct blk_mq_tags **tagsptr, unsigned int tdepth, | |
469 | bool can_grow) | |
e3a2b3f9 | 470 | { |
70f36b60 JA |
471 | struct blk_mq_tags *tags = *tagsptr; |
472 | ||
473 | if (tdepth <= tags->nr_reserved_tags) | |
e3a2b3f9 JA |
474 | return -EINVAL; |
475 | ||
476 | /* | |
70f36b60 JA |
477 | * If we are allowed to grow beyond the original size, allocate |
478 | * a new set of tags before freeing the old one. | |
e3a2b3f9 | 479 | */ |
70f36b60 JA |
480 | if (tdepth > tags->nr_tags) { |
481 | struct blk_mq_tag_set *set = hctx->queue->tag_set; | |
482 | struct blk_mq_tags *new; | |
483 | bool ret; | |
484 | ||
485 | if (!can_grow) | |
486 | return -EINVAL; | |
487 | ||
488 | /* | |
489 | * We need some sort of upper limit, set it high enough that | |
490 | * no valid use cases should require more. | |
491 | */ | |
492 | if (tdepth > 16 * BLKDEV_MAX_RQ) | |
493 | return -EINVAL; | |
494 | ||
75d6e175 ML |
495 | new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, |
496 | tags->nr_reserved_tags); | |
70f36b60 JA |
497 | if (!new) |
498 | return -ENOMEM; | |
499 | ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth); | |
500 | if (ret) { | |
501 | blk_mq_free_rq_map(new); | |
502 | return -ENOMEM; | |
503 | } | |
504 | ||
505 | blk_mq_free_rqs(set, *tagsptr, hctx->queue_num); | |
506 | blk_mq_free_rq_map(*tagsptr); | |
507 | *tagsptr = new; | |
508 | } else { | |
509 | /* | |
510 | * Don't need (or can't) update reserved tags here, they | |
511 | * remain static and should never need resizing. | |
512 | */ | |
75d6e175 ML |
513 | sbitmap_queue_resize(&tags->bitmap_tags, |
514 | tdepth - tags->nr_reserved_tags); | |
70f36b60 | 515 | } |
88459642 | 516 | |
e3a2b3f9 JA |
517 | return 0; |
518 | } | |
519 | ||
205fb5f5 BVA |
520 | /** |
521 | * blk_mq_unique_tag() - return a tag that is unique queue-wide | |
522 | * @rq: request for which to compute a unique tag | |
523 | * | |
524 | * The tag field in struct request is unique per hardware queue but not over | |
525 | * all hardware queues. Hence this function that returns a tag with the | |
526 | * hardware context index in the upper bits and the per hardware queue tag in | |
527 | * the lower bits. | |
528 | * | |
529 | * Note: When called for a request that is queued on a non-multiqueue request | |
530 | * queue, the hardware context index is set to zero. | |
531 | */ | |
532 | u32 blk_mq_unique_tag(struct request *rq) | |
533 | { | |
ea4f995e | 534 | return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) | |
205fb5f5 BVA |
535 | (rq->tag & BLK_MQ_UNIQUE_TAG_MASK); |
536 | } | |
537 | EXPORT_SYMBOL(blk_mq_unique_tag); |