Commit | Line | Data |
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320ae51f JA |
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> | |
4bb659b1 | 3 | #include <linux/random.h> |
320ae51f JA |
4 | |
5 | #include <linux/blk-mq.h> | |
6 | #include "blk.h" | |
7 | #include "blk-mq.h" | |
8 | #include "blk-mq-tag.h" | |
9 | ||
0d2602ca | 10 | void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved) |
320ae51f | 11 | { |
4bb659b1 JA |
12 | int tag, zero = 0; |
13 | ||
0d2602ca JA |
14 | tag = blk_mq_get_tag(hctx, &zero, __GFP_WAIT, reserved); |
15 | blk_mq_put_tag(hctx, tag, &zero); | |
4bb659b1 JA |
16 | } |
17 | ||
18 | static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt) | |
19 | { | |
20 | int i; | |
21 | ||
22 | for (i = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 23 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 JA |
24 | int ret; |
25 | ||
26 | ret = find_first_zero_bit(&bm->word, bm->depth); | |
27 | if (ret < bm->depth) | |
28 | return true; | |
29 | } | |
30 | ||
31 | return false; | |
320ae51f JA |
32 | } |
33 | ||
34 | bool blk_mq_has_free_tags(struct blk_mq_tags *tags) | |
35 | { | |
4bb659b1 JA |
36 | if (!tags) |
37 | return true; | |
38 | ||
39 | return bt_has_free_tags(&tags->bitmap_tags); | |
40 | } | |
41 | ||
0d2602ca JA |
42 | static inline void bt_index_inc(unsigned int *index) |
43 | { | |
44 | *index = (*index + 1) & (BT_WAIT_QUEUES - 1); | |
45 | } | |
46 | ||
47 | /* | |
48 | * If a previously inactive queue goes active, bump the active user count. | |
49 | */ | |
50 | bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) | |
51 | { | |
52 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) && | |
53 | !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
54 | atomic_inc(&hctx->tags->active_queues); | |
55 | ||
56 | return true; | |
57 | } | |
58 | ||
59 | /* | |
e3a2b3f9 | 60 | * Wakeup all potentially sleeping on normal (non-reserved) tags |
0d2602ca | 61 | */ |
e3a2b3f9 | 62 | static void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags) |
0d2602ca | 63 | { |
0d2602ca JA |
64 | struct blk_mq_bitmap_tags *bt; |
65 | int i, wake_index; | |
66 | ||
0d2602ca JA |
67 | bt = &tags->bitmap_tags; |
68 | wake_index = bt->wake_index; | |
69 | for (i = 0; i < BT_WAIT_QUEUES; i++) { | |
70 | struct bt_wait_state *bs = &bt->bs[wake_index]; | |
71 | ||
72 | if (waitqueue_active(&bs->wait)) | |
73 | wake_up(&bs->wait); | |
74 | ||
75 | bt_index_inc(&wake_index); | |
76 | } | |
77 | } | |
78 | ||
e3a2b3f9 JA |
79 | /* |
80 | * If a previously busy queue goes inactive, potential waiters could now | |
81 | * be allowed to queue. Wake them up and check. | |
82 | */ | |
83 | void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) | |
84 | { | |
85 | struct blk_mq_tags *tags = hctx->tags; | |
86 | ||
87 | if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
88 | return; | |
89 | ||
90 | atomic_dec(&tags->active_queues); | |
91 | ||
92 | blk_mq_tag_wakeup_all(tags); | |
93 | } | |
94 | ||
0d2602ca JA |
95 | /* |
96 | * For shared tag users, we track the number of currently active users | |
97 | * and attempt to provide a fair share of the tag depth for each of them. | |
98 | */ | |
99 | static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, | |
100 | struct blk_mq_bitmap_tags *bt) | |
101 | { | |
102 | unsigned int depth, users; | |
103 | ||
104 | if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED)) | |
105 | return true; | |
106 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
107 | return true; | |
108 | ||
109 | /* | |
110 | * Don't try dividing an ant | |
111 | */ | |
112 | if (bt->depth == 1) | |
113 | return true; | |
114 | ||
115 | users = atomic_read(&hctx->tags->active_queues); | |
116 | if (!users) | |
117 | return true; | |
118 | ||
119 | /* | |
120 | * Allow at least some tags | |
121 | */ | |
122 | depth = max((bt->depth + users - 1) / users, 4U); | |
123 | return atomic_read(&hctx->nr_active) < depth; | |
124 | } | |
125 | ||
e93ecf60 | 126 | static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag) |
4bb659b1 JA |
127 | { |
128 | int tag, org_last_tag, end; | |
129 | ||
59d13bf5 | 130 | org_last_tag = last_tag; |
4bb659b1 JA |
131 | end = bm->depth; |
132 | do { | |
133 | restart: | |
134 | tag = find_next_zero_bit(&bm->word, end, last_tag); | |
135 | if (unlikely(tag >= end)) { | |
136 | /* | |
137 | * We started with an offset, start from 0 to | |
138 | * exhaust the map. | |
139 | */ | |
140 | if (org_last_tag && last_tag) { | |
141 | end = last_tag; | |
142 | last_tag = 0; | |
143 | goto restart; | |
144 | } | |
145 | return -1; | |
146 | } | |
147 | last_tag = tag + 1; | |
148 | } while (test_and_set_bit_lock(tag, &bm->word)); | |
149 | ||
150 | return tag; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Straight forward bitmap tag implementation, where each bit is a tag | |
155 | * (cleared == free, and set == busy). The small twist is using per-cpu | |
156 | * last_tag caches, which blk-mq stores in the blk_mq_ctx software queue | |
157 | * contexts. This enables us to drastically limit the space searched, | |
158 | * without dirtying an extra shared cacheline like we would if we stored | |
159 | * the cache value inside the shared blk_mq_bitmap_tags structure. On top | |
160 | * of that, each word of tags is in a separate cacheline. This means that | |
161 | * multiple users will tend to stick to different cachelines, at least | |
162 | * until the map is exhausted. | |
163 | */ | |
0d2602ca JA |
164 | static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt, |
165 | unsigned int *tag_cache) | |
4bb659b1 JA |
166 | { |
167 | unsigned int last_tag, org_last_tag; | |
168 | int index, i, tag; | |
169 | ||
0d2602ca JA |
170 | if (!hctx_may_queue(hctx, bt)) |
171 | return -1; | |
172 | ||
4bb659b1 | 173 | last_tag = org_last_tag = *tag_cache; |
59d13bf5 | 174 | index = TAG_TO_INDEX(bt, last_tag); |
4bb659b1 JA |
175 | |
176 | for (i = 0; i < bt->map_nr; i++) { | |
59d13bf5 | 177 | tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag)); |
4bb659b1 | 178 | if (tag != -1) { |
59d13bf5 | 179 | tag += (index << bt->bits_per_word); |
4bb659b1 JA |
180 | goto done; |
181 | } | |
182 | ||
183 | last_tag = 0; | |
184 | if (++index >= bt->map_nr) | |
185 | index = 0; | |
186 | } | |
187 | ||
188 | *tag_cache = 0; | |
189 | return -1; | |
190 | ||
191 | /* | |
192 | * Only update the cache from the allocation path, if we ended | |
193 | * up using the specific cached tag. | |
194 | */ | |
195 | done: | |
196 | if (tag == org_last_tag) { | |
197 | last_tag = tag + 1; | |
198 | if (last_tag >= bt->depth - 1) | |
199 | last_tag = 0; | |
200 | ||
201 | *tag_cache = last_tag; | |
202 | } | |
203 | ||
204 | return tag; | |
205 | } | |
206 | ||
4bb659b1 JA |
207 | static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt, |
208 | struct blk_mq_hw_ctx *hctx) | |
209 | { | |
210 | struct bt_wait_state *bs; | |
211 | ||
212 | if (!hctx) | |
213 | return &bt->bs[0]; | |
214 | ||
215 | bs = &bt->bs[hctx->wait_index]; | |
216 | bt_index_inc(&hctx->wait_index); | |
217 | return bs; | |
320ae51f JA |
218 | } |
219 | ||
4bb659b1 JA |
220 | static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, |
221 | unsigned int *last_tag, gfp_t gfp) | |
320ae51f | 222 | { |
4bb659b1 JA |
223 | struct bt_wait_state *bs; |
224 | DEFINE_WAIT(wait); | |
320ae51f JA |
225 | int tag; |
226 | ||
0d2602ca | 227 | tag = __bt_get(hctx, bt, last_tag); |
4bb659b1 JA |
228 | if (tag != -1) |
229 | return tag; | |
230 | ||
231 | if (!(gfp & __GFP_WAIT)) | |
232 | return -1; | |
233 | ||
234 | bs = bt_wait_ptr(bt, hctx); | |
235 | do { | |
236 | bool was_empty; | |
237 | ||
238 | was_empty = list_empty(&wait.task_list); | |
239 | prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); | |
240 | ||
0d2602ca | 241 | tag = __bt_get(hctx, bt, last_tag); |
4bb659b1 JA |
242 | if (tag != -1) |
243 | break; | |
244 | ||
245 | if (was_empty) | |
246 | atomic_set(&bs->wait_cnt, bt->wake_cnt); | |
247 | ||
248 | io_schedule(); | |
249 | } while (1); | |
250 | ||
251 | finish_wait(&bs->wait, &wait); | |
252 | return tag; | |
253 | } | |
254 | ||
255 | static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, | |
256 | struct blk_mq_hw_ctx *hctx, | |
257 | unsigned int *last_tag, gfp_t gfp) | |
258 | { | |
259 | int tag; | |
260 | ||
261 | tag = bt_get(&tags->bitmap_tags, hctx, last_tag, gfp); | |
262 | if (tag >= 0) | |
263 | return tag + tags->nr_reserved_tags; | |
264 | ||
265 | return BLK_MQ_TAG_FAIL; | |
320ae51f JA |
266 | } |
267 | ||
268 | static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags, | |
269 | gfp_t gfp) | |
270 | { | |
4bb659b1 | 271 | int tag, zero = 0; |
320ae51f JA |
272 | |
273 | if (unlikely(!tags->nr_reserved_tags)) { | |
274 | WARN_ON_ONCE(1); | |
275 | return BLK_MQ_TAG_FAIL; | |
276 | } | |
277 | ||
4bb659b1 | 278 | tag = bt_get(&tags->breserved_tags, NULL, &zero, gfp); |
320ae51f JA |
279 | if (tag < 0) |
280 | return BLK_MQ_TAG_FAIL; | |
4bb659b1 | 281 | |
320ae51f JA |
282 | return tag; |
283 | } | |
284 | ||
0d2602ca | 285 | unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, |
4bb659b1 | 286 | gfp_t gfp, bool reserved) |
320ae51f JA |
287 | { |
288 | if (!reserved) | |
0d2602ca | 289 | return __blk_mq_get_tag(hctx->tags, hctx, last_tag, gfp); |
320ae51f | 290 | |
0d2602ca | 291 | return __blk_mq_get_reserved_tag(hctx->tags, gfp); |
320ae51f JA |
292 | } |
293 | ||
4bb659b1 JA |
294 | static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt) |
295 | { | |
296 | int i, wake_index; | |
297 | ||
298 | wake_index = bt->wake_index; | |
299 | for (i = 0; i < BT_WAIT_QUEUES; i++) { | |
300 | struct bt_wait_state *bs = &bt->bs[wake_index]; | |
301 | ||
302 | if (waitqueue_active(&bs->wait)) { | |
303 | if (wake_index != bt->wake_index) | |
304 | bt->wake_index = wake_index; | |
305 | ||
306 | return bs; | |
307 | } | |
308 | ||
309 | bt_index_inc(&wake_index); | |
310 | } | |
311 | ||
312 | return NULL; | |
313 | } | |
314 | ||
315 | static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) | |
316 | { | |
59d13bf5 | 317 | const int index = TAG_TO_INDEX(bt, tag); |
4bb659b1 JA |
318 | struct bt_wait_state *bs; |
319 | ||
0289b2e1 ML |
320 | /* |
321 | * The unlock memory barrier need to order access to req in free | |
322 | * path and clearing tag bit | |
323 | */ | |
324 | clear_bit_unlock(TAG_TO_BIT(bt, tag), &bt->map[index].word); | |
4bb659b1 JA |
325 | |
326 | bs = bt_wake_ptr(bt); | |
327 | if (bs && atomic_dec_and_test(&bs->wait_cnt)) { | |
4bb659b1 JA |
328 | atomic_set(&bs->wait_cnt, bt->wake_cnt); |
329 | bt_index_inc(&bt->wake_index); | |
330 | wake_up(&bs->wait); | |
331 | } | |
332 | } | |
333 | ||
320ae51f JA |
334 | static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag) |
335 | { | |
336 | BUG_ON(tag >= tags->nr_tags); | |
337 | ||
4bb659b1 | 338 | bt_clear_tag(&tags->bitmap_tags, tag); |
320ae51f JA |
339 | } |
340 | ||
341 | static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags, | |
342 | unsigned int tag) | |
343 | { | |
344 | BUG_ON(tag >= tags->nr_reserved_tags); | |
345 | ||
4bb659b1 | 346 | bt_clear_tag(&tags->breserved_tags, tag); |
320ae51f JA |
347 | } |
348 | ||
0d2602ca | 349 | void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, |
4bb659b1 | 350 | unsigned int *last_tag) |
320ae51f | 351 | { |
0d2602ca JA |
352 | struct blk_mq_tags *tags = hctx->tags; |
353 | ||
4bb659b1 JA |
354 | if (tag >= tags->nr_reserved_tags) { |
355 | const int real_tag = tag - tags->nr_reserved_tags; | |
356 | ||
357 | __blk_mq_put_tag(tags, real_tag); | |
358 | *last_tag = real_tag; | |
359 | } else | |
320ae51f JA |
360 | __blk_mq_put_reserved_tag(tags, tag); |
361 | } | |
362 | ||
4bb659b1 JA |
363 | static void bt_for_each_free(struct blk_mq_bitmap_tags *bt, |
364 | unsigned long *free_map, unsigned int off) | |
320ae51f | 365 | { |
4bb659b1 JA |
366 | int i; |
367 | ||
368 | for (i = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 369 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 JA |
370 | int bit = 0; |
371 | ||
372 | do { | |
373 | bit = find_next_zero_bit(&bm->word, bm->depth, bit); | |
374 | if (bit >= bm->depth) | |
375 | break; | |
376 | ||
377 | __set_bit(bit + off, free_map); | |
378 | bit++; | |
379 | } while (1); | |
380 | ||
59d13bf5 | 381 | off += (1 << bt->bits_per_word); |
4bb659b1 | 382 | } |
320ae51f JA |
383 | } |
384 | ||
385 | void blk_mq_tag_busy_iter(struct blk_mq_tags *tags, | |
386 | void (*fn)(void *, unsigned long *), void *data) | |
387 | { | |
388 | unsigned long *tag_map; | |
389 | size_t map_size; | |
390 | ||
391 | map_size = ALIGN(tags->nr_tags, BITS_PER_LONG) / BITS_PER_LONG; | |
392 | tag_map = kzalloc(map_size * sizeof(unsigned long), GFP_ATOMIC); | |
393 | if (!tag_map) | |
394 | return; | |
395 | ||
4bb659b1 | 396 | bt_for_each_free(&tags->bitmap_tags, tag_map, tags->nr_reserved_tags); |
320ae51f | 397 | if (tags->nr_reserved_tags) |
4bb659b1 | 398 | bt_for_each_free(&tags->breserved_tags, tag_map, 0); |
320ae51f JA |
399 | |
400 | fn(data, tag_map); | |
401 | kfree(tag_map); | |
402 | } | |
edf866b3 | 403 | EXPORT_SYMBOL(blk_mq_tag_busy_iter); |
320ae51f | 404 | |
4bb659b1 JA |
405 | static unsigned int bt_unused_tags(struct blk_mq_bitmap_tags *bt) |
406 | { | |
407 | unsigned int i, used; | |
408 | ||
409 | for (i = 0, used = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 410 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 JA |
411 | |
412 | used += bitmap_weight(&bm->word, bm->depth); | |
413 | } | |
414 | ||
415 | return bt->depth - used; | |
416 | } | |
417 | ||
e3a2b3f9 JA |
418 | static void bt_update_count(struct blk_mq_bitmap_tags *bt, |
419 | unsigned int depth) | |
420 | { | |
421 | unsigned int tags_per_word = 1U << bt->bits_per_word; | |
422 | unsigned int map_depth = depth; | |
423 | ||
424 | if (depth) { | |
425 | int i; | |
426 | ||
427 | for (i = 0; i < bt->map_nr; i++) { | |
428 | bt->map[i].depth = min(map_depth, tags_per_word); | |
429 | map_depth -= bt->map[i].depth; | |
430 | } | |
431 | } | |
432 | ||
433 | bt->wake_cnt = BT_WAIT_BATCH; | |
434 | if (bt->wake_cnt > depth / 4) | |
435 | bt->wake_cnt = max(1U, depth / 4); | |
436 | ||
437 | bt->depth = depth; | |
438 | } | |
439 | ||
4bb659b1 JA |
440 | static int bt_alloc(struct blk_mq_bitmap_tags *bt, unsigned int depth, |
441 | int node, bool reserved) | |
442 | { | |
443 | int i; | |
444 | ||
59d13bf5 JA |
445 | bt->bits_per_word = ilog2(BITS_PER_LONG); |
446 | ||
4bb659b1 JA |
447 | /* |
448 | * Depth can be zero for reserved tags, that's not a failure | |
449 | * condition. | |
450 | */ | |
451 | if (depth) { | |
e3a2b3f9 | 452 | unsigned int nr, tags_per_word; |
59d13bf5 JA |
453 | |
454 | tags_per_word = (1 << bt->bits_per_word); | |
455 | ||
456 | /* | |
457 | * If the tag space is small, shrink the number of tags | |
458 | * per word so we spread over a few cachelines, at least. | |
459 | * If less than 4 tags, just forget about it, it's not | |
460 | * going to work optimally anyway. | |
461 | */ | |
462 | if (depth >= 4) { | |
463 | while (tags_per_word * 4 > depth) { | |
464 | bt->bits_per_word--; | |
465 | tags_per_word = (1 << bt->bits_per_word); | |
466 | } | |
467 | } | |
4bb659b1 | 468 | |
59d13bf5 | 469 | nr = ALIGN(depth, tags_per_word) / tags_per_word; |
e93ecf60 | 470 | bt->map = kzalloc_node(nr * sizeof(struct blk_align_bitmap), |
4bb659b1 JA |
471 | GFP_KERNEL, node); |
472 | if (!bt->map) | |
473 | return -ENOMEM; | |
474 | ||
475 | bt->map_nr = nr; | |
4bb659b1 JA |
476 | } |
477 | ||
478 | bt->bs = kzalloc(BT_WAIT_QUEUES * sizeof(*bt->bs), GFP_KERNEL); | |
479 | if (!bt->bs) { | |
480 | kfree(bt->map); | |
481 | return -ENOMEM; | |
482 | } | |
483 | ||
484 | for (i = 0; i < BT_WAIT_QUEUES; i++) | |
485 | init_waitqueue_head(&bt->bs[i].wait); | |
486 | ||
e3a2b3f9 | 487 | bt_update_count(bt, depth); |
4bb659b1 JA |
488 | return 0; |
489 | } | |
490 | ||
491 | static void bt_free(struct blk_mq_bitmap_tags *bt) | |
492 | { | |
493 | kfree(bt->map); | |
494 | kfree(bt->bs); | |
495 | } | |
496 | ||
497 | static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, | |
498 | int node) | |
499 | { | |
500 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; | |
501 | ||
502 | if (bt_alloc(&tags->bitmap_tags, depth, node, false)) | |
503 | goto enomem; | |
504 | if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true)) | |
505 | goto enomem; | |
506 | ||
507 | return tags; | |
508 | enomem: | |
509 | bt_free(&tags->bitmap_tags); | |
510 | kfree(tags); | |
511 | return NULL; | |
512 | } | |
513 | ||
320ae51f JA |
514 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, |
515 | unsigned int reserved_tags, int node) | |
516 | { | |
320ae51f | 517 | struct blk_mq_tags *tags; |
320ae51f JA |
518 | |
519 | if (total_tags > BLK_MQ_TAG_MAX) { | |
520 | pr_err("blk-mq: tag depth too large\n"); | |
521 | return NULL; | |
522 | } | |
523 | ||
524 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); | |
525 | if (!tags) | |
526 | return NULL; | |
527 | ||
320ae51f JA |
528 | tags->nr_tags = total_tags; |
529 | tags->nr_reserved_tags = reserved_tags; | |
320ae51f | 530 | |
4bb659b1 | 531 | return blk_mq_init_bitmap_tags(tags, node); |
320ae51f JA |
532 | } |
533 | ||
534 | void blk_mq_free_tags(struct blk_mq_tags *tags) | |
535 | { | |
4bb659b1 JA |
536 | bt_free(&tags->bitmap_tags); |
537 | bt_free(&tags->breserved_tags); | |
320ae51f JA |
538 | kfree(tags); |
539 | } | |
540 | ||
4bb659b1 JA |
541 | void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *tag) |
542 | { | |
543 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; | |
544 | ||
9d3d21ae | 545 | *tag = prandom_u32() % depth; |
4bb659b1 JA |
546 | } |
547 | ||
e3a2b3f9 JA |
548 | int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int tdepth) |
549 | { | |
550 | tdepth -= tags->nr_reserved_tags; | |
551 | if (tdepth > tags->nr_tags) | |
552 | return -EINVAL; | |
553 | ||
554 | /* | |
555 | * Don't need (or can't) update reserved tags here, they remain | |
556 | * static and should never need resizing. | |
557 | */ | |
558 | bt_update_count(&tags->bitmap_tags, tdepth); | |
559 | blk_mq_tag_wakeup_all(tags); | |
560 | return 0; | |
561 | } | |
562 | ||
320ae51f JA |
563 | ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) |
564 | { | |
565 | char *orig_page = page; | |
4bb659b1 | 566 | unsigned int free, res; |
320ae51f JA |
567 | |
568 | if (!tags) | |
569 | return 0; | |
570 | ||
59d13bf5 JA |
571 | page += sprintf(page, "nr_tags=%u, reserved_tags=%u, " |
572 | "bits_per_word=%u\n", | |
573 | tags->nr_tags, tags->nr_reserved_tags, | |
574 | tags->bitmap_tags.bits_per_word); | |
320ae51f | 575 | |
4bb659b1 JA |
576 | free = bt_unused_tags(&tags->bitmap_tags); |
577 | res = bt_unused_tags(&tags->breserved_tags); | |
320ae51f | 578 | |
4bb659b1 | 579 | page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", free, res); |
0d2602ca | 580 | page += sprintf(page, "active_queues=%u\n", atomic_read(&tags->active_queues)); |
320ae51f JA |
581 | |
582 | return page - orig_page; | |
583 | } |