| 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 | static void blk_mq_update_wake_batch(struct blk_mq_tags *tags, |
| 21 | unsigned int users) |
| 22 | { |
| 23 | if (!users) |
| 24 | return; |
| 25 | |
| 26 | sbitmap_queue_recalculate_wake_batch(&tags->bitmap_tags, |
| 27 | users); |
| 28 | 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 | void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) |
| 39 | { |
| 40 | unsigned int users; |
| 41 | unsigned long flags; |
| 42 | struct blk_mq_tags *tags = hctx->tags; |
| 43 | |
| 44 | /* |
| 45 | * calling test_bit() prior to test_and_set_bit() is intentional, |
| 46 | * it avoids dirtying the cacheline if the queue is already active. |
| 47 | */ |
| 48 | if (blk_mq_is_shared_tags(hctx->flags)) { |
| 49 | struct request_queue *q = hctx->queue; |
| 50 | |
| 51 | if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) || |
| 52 | test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags)) |
| 53 | return; |
| 54 | } else { |
| 55 | if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) || |
| 56 | test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) |
| 57 | return; |
| 58 | } |
| 59 | |
| 60 | spin_lock_irqsave(&tags->lock, flags); |
| 61 | users = tags->active_queues + 1; |
| 62 | WRITE_ONCE(tags->active_queues, users); |
| 63 | blk_mq_update_wake_batch(tags, users); |
| 64 | spin_unlock_irqrestore(&tags->lock, flags); |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * Wakeup all potentially sleeping on tags |
| 69 | */ |
| 70 | void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve) |
| 71 | { |
| 72 | sbitmap_queue_wake_all(&tags->bitmap_tags); |
| 73 | if (include_reserve) |
| 74 | sbitmap_queue_wake_all(&tags->breserved_tags); |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * If a previously busy queue goes inactive, potential waiters could now |
| 79 | * be allowed to queue. Wake them up and check. |
| 80 | */ |
| 81 | void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) |
| 82 | { |
| 83 | struct blk_mq_tags *tags = hctx->tags; |
| 84 | unsigned int users; |
| 85 | |
| 86 | if (blk_mq_is_shared_tags(hctx->flags)) { |
| 87 | struct request_queue *q = hctx->queue; |
| 88 | |
| 89 | if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE, |
| 90 | &q->queue_flags)) |
| 91 | return; |
| 92 | } else { |
| 93 | if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) |
| 94 | return; |
| 95 | } |
| 96 | |
| 97 | spin_lock_irq(&tags->lock); |
| 98 | users = tags->active_queues - 1; |
| 99 | WRITE_ONCE(tags->active_queues, users); |
| 100 | blk_mq_update_wake_batch(tags, users); |
| 101 | spin_unlock_irq(&tags->lock); |
| 102 | |
| 103 | blk_mq_tag_wakeup_all(tags, false); |
| 104 | } |
| 105 | |
| 106 | static int __blk_mq_get_tag(struct blk_mq_alloc_data *data, |
| 107 | struct sbitmap_queue *bt) |
| 108 | { |
| 109 | if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) && |
| 110 | !hctx_may_queue(data->hctx, bt)) |
| 111 | return BLK_MQ_NO_TAG; |
| 112 | |
| 113 | if (data->shallow_depth) |
| 114 | return sbitmap_queue_get_shallow(bt, data->shallow_depth); |
| 115 | else |
| 116 | return __sbitmap_queue_get(bt); |
| 117 | } |
| 118 | |
| 119 | unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags, |
| 120 | unsigned int *offset) |
| 121 | { |
| 122 | struct blk_mq_tags *tags = blk_mq_tags_from_data(data); |
| 123 | struct sbitmap_queue *bt = &tags->bitmap_tags; |
| 124 | unsigned long ret; |
| 125 | |
| 126 | if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED || |
| 127 | data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) |
| 128 | return 0; |
| 129 | ret = __sbitmap_queue_get_batch(bt, nr_tags, offset); |
| 130 | *offset += tags->nr_reserved_tags; |
| 131 | return ret; |
| 132 | } |
| 133 | |
| 134 | unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) |
| 135 | { |
| 136 | struct blk_mq_tags *tags = blk_mq_tags_from_data(data); |
| 137 | struct sbitmap_queue *bt; |
| 138 | struct sbq_wait_state *ws; |
| 139 | DEFINE_SBQ_WAIT(wait); |
| 140 | unsigned int tag_offset; |
| 141 | int tag; |
| 142 | |
| 143 | if (data->flags & BLK_MQ_REQ_RESERVED) { |
| 144 | if (unlikely(!tags->nr_reserved_tags)) { |
| 145 | WARN_ON_ONCE(1); |
| 146 | return BLK_MQ_NO_TAG; |
| 147 | } |
| 148 | bt = &tags->breserved_tags; |
| 149 | tag_offset = 0; |
| 150 | } else { |
| 151 | bt = &tags->bitmap_tags; |
| 152 | tag_offset = tags->nr_reserved_tags; |
| 153 | } |
| 154 | |
| 155 | tag = __blk_mq_get_tag(data, bt); |
| 156 | if (tag != BLK_MQ_NO_TAG) |
| 157 | goto found_tag; |
| 158 | |
| 159 | if (data->flags & BLK_MQ_REQ_NOWAIT) |
| 160 | return BLK_MQ_NO_TAG; |
| 161 | |
| 162 | ws = bt_wait_ptr(bt, data->hctx); |
| 163 | do { |
| 164 | struct sbitmap_queue *bt_prev; |
| 165 | |
| 166 | /* |
| 167 | * We're out of tags on this hardware queue, kick any |
| 168 | * pending IO submits before going to sleep waiting for |
| 169 | * some to complete. |
| 170 | */ |
| 171 | blk_mq_run_hw_queue(data->hctx, false); |
| 172 | |
| 173 | /* |
| 174 | * Retry tag allocation after running the hardware queue, |
| 175 | * as running the queue may also have found completions. |
| 176 | */ |
| 177 | tag = __blk_mq_get_tag(data, bt); |
| 178 | if (tag != BLK_MQ_NO_TAG) |
| 179 | break; |
| 180 | |
| 181 | sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE); |
| 182 | |
| 183 | tag = __blk_mq_get_tag(data, bt); |
| 184 | if (tag != BLK_MQ_NO_TAG) |
| 185 | break; |
| 186 | |
| 187 | bt_prev = bt; |
| 188 | io_schedule(); |
| 189 | |
| 190 | sbitmap_finish_wait(bt, ws, &wait); |
| 191 | |
| 192 | data->ctx = blk_mq_get_ctx(data->q); |
| 193 | data->hctx = blk_mq_map_queue(data->q, data->cmd_flags, |
| 194 | data->ctx); |
| 195 | tags = blk_mq_tags_from_data(data); |
| 196 | if (data->flags & BLK_MQ_REQ_RESERVED) |
| 197 | bt = &tags->breserved_tags; |
| 198 | else |
| 199 | bt = &tags->bitmap_tags; |
| 200 | |
| 201 | /* |
| 202 | * If destination hw queue is changed, fake wake up on |
| 203 | * previous queue for compensating the wake up miss, so |
| 204 | * other allocations on previous queue won't be starved. |
| 205 | */ |
| 206 | if (bt != bt_prev) |
| 207 | sbitmap_queue_wake_up(bt_prev, 1); |
| 208 | |
| 209 | ws = bt_wait_ptr(bt, data->hctx); |
| 210 | } while (1); |
| 211 | |
| 212 | sbitmap_finish_wait(bt, ws, &wait); |
| 213 | |
| 214 | found_tag: |
| 215 | /* |
| 216 | * Give up this allocation if the hctx is inactive. The caller will |
| 217 | * retry on an active hctx. |
| 218 | */ |
| 219 | if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) { |
| 220 | blk_mq_put_tag(tags, data->ctx, tag + tag_offset); |
| 221 | return BLK_MQ_NO_TAG; |
| 222 | } |
| 223 | return tag + tag_offset; |
| 224 | } |
| 225 | |
| 226 | void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx, |
| 227 | unsigned int tag) |
| 228 | { |
| 229 | if (!blk_mq_tag_is_reserved(tags, tag)) { |
| 230 | const int real_tag = tag - tags->nr_reserved_tags; |
| 231 | |
| 232 | BUG_ON(real_tag >= tags->nr_tags); |
| 233 | sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu); |
| 234 | } else { |
| 235 | sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu); |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags) |
| 240 | { |
| 241 | sbitmap_queue_clear_batch(&tags->bitmap_tags, tags->nr_reserved_tags, |
| 242 | tag_array, nr_tags); |
| 243 | } |
| 244 | |
| 245 | struct bt_iter_data { |
| 246 | struct blk_mq_hw_ctx *hctx; |
| 247 | struct request_queue *q; |
| 248 | busy_tag_iter_fn *fn; |
| 249 | void *data; |
| 250 | bool reserved; |
| 251 | }; |
| 252 | |
| 253 | static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, |
| 254 | unsigned int bitnr) |
| 255 | { |
| 256 | struct request *rq; |
| 257 | unsigned long flags; |
| 258 | |
| 259 | spin_lock_irqsave(&tags->lock, flags); |
| 260 | rq = tags->rqs[bitnr]; |
| 261 | if (!rq || rq->tag != bitnr || !req_ref_inc_not_zero(rq)) |
| 262 | rq = NULL; |
| 263 | spin_unlock_irqrestore(&tags->lock, flags); |
| 264 | return rq; |
| 265 | } |
| 266 | |
| 267 | static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) |
| 268 | { |
| 269 | struct bt_iter_data *iter_data = data; |
| 270 | struct blk_mq_hw_ctx *hctx = iter_data->hctx; |
| 271 | struct request_queue *q = iter_data->q; |
| 272 | struct blk_mq_tag_set *set = q->tag_set; |
| 273 | struct blk_mq_tags *tags; |
| 274 | struct request *rq; |
| 275 | bool ret = true; |
| 276 | |
| 277 | if (blk_mq_is_shared_tags(set->flags)) |
| 278 | tags = set->shared_tags; |
| 279 | else |
| 280 | tags = hctx->tags; |
| 281 | |
| 282 | if (!iter_data->reserved) |
| 283 | bitnr += tags->nr_reserved_tags; |
| 284 | /* |
| 285 | * We can hit rq == NULL here, because the tagging functions |
| 286 | * test and set the bit before assigning ->rqs[]. |
| 287 | */ |
| 288 | rq = blk_mq_find_and_get_req(tags, bitnr); |
| 289 | if (!rq) |
| 290 | return true; |
| 291 | |
| 292 | if (rq->q == q && (!hctx || rq->mq_hctx == hctx)) |
| 293 | ret = iter_data->fn(rq, iter_data->data); |
| 294 | blk_mq_put_rq_ref(rq); |
| 295 | return ret; |
| 296 | } |
| 297 | |
| 298 | /** |
| 299 | * bt_for_each - iterate over the requests associated with a hardware queue |
| 300 | * @hctx: Hardware queue to examine. |
| 301 | * @q: Request queue to examine. |
| 302 | * @bt: sbitmap to examine. This is either the breserved_tags member |
| 303 | * or the bitmap_tags member of struct blk_mq_tags. |
| 304 | * @fn: Pointer to the function that will be called for each request |
| 305 | * associated with @hctx that has been assigned a driver tag. |
| 306 | * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved) |
| 307 | * where rq is a pointer to a request. Return true to continue |
| 308 | * iterating tags, false to stop. |
| 309 | * @data: Will be passed as third argument to @fn. |
| 310 | * @reserved: Indicates whether @bt is the breserved_tags member or the |
| 311 | * bitmap_tags member of struct blk_mq_tags. |
| 312 | */ |
| 313 | static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct request_queue *q, |
| 314 | struct sbitmap_queue *bt, busy_tag_iter_fn *fn, |
| 315 | void *data, bool reserved) |
| 316 | { |
| 317 | struct bt_iter_data iter_data = { |
| 318 | .hctx = hctx, |
| 319 | .fn = fn, |
| 320 | .data = data, |
| 321 | .reserved = reserved, |
| 322 | .q = q, |
| 323 | }; |
| 324 | |
| 325 | sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data); |
| 326 | } |
| 327 | |
| 328 | struct bt_tags_iter_data { |
| 329 | struct blk_mq_tags *tags; |
| 330 | busy_tag_iter_fn *fn; |
| 331 | void *data; |
| 332 | unsigned int flags; |
| 333 | }; |
| 334 | |
| 335 | #define BT_TAG_ITER_RESERVED (1 << 0) |
| 336 | #define BT_TAG_ITER_STARTED (1 << 1) |
| 337 | #define BT_TAG_ITER_STATIC_RQS (1 << 2) |
| 338 | |
| 339 | static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) |
| 340 | { |
| 341 | struct bt_tags_iter_data *iter_data = data; |
| 342 | struct blk_mq_tags *tags = iter_data->tags; |
| 343 | struct request *rq; |
| 344 | bool ret = true; |
| 345 | bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS); |
| 346 | |
| 347 | if (!(iter_data->flags & BT_TAG_ITER_RESERVED)) |
| 348 | bitnr += tags->nr_reserved_tags; |
| 349 | |
| 350 | /* |
| 351 | * We can hit rq == NULL here, because the tagging functions |
| 352 | * test and set the bit before assigning ->rqs[]. |
| 353 | */ |
| 354 | if (iter_static_rqs) |
| 355 | rq = tags->static_rqs[bitnr]; |
| 356 | else |
| 357 | rq = blk_mq_find_and_get_req(tags, bitnr); |
| 358 | if (!rq) |
| 359 | return true; |
| 360 | |
| 361 | if (!(iter_data->flags & BT_TAG_ITER_STARTED) || |
| 362 | blk_mq_request_started(rq)) |
| 363 | ret = iter_data->fn(rq, iter_data->data); |
| 364 | if (!iter_static_rqs) |
| 365 | blk_mq_put_rq_ref(rq); |
| 366 | return ret; |
| 367 | } |
| 368 | |
| 369 | /** |
| 370 | * bt_tags_for_each - iterate over the requests in a tag map |
| 371 | * @tags: Tag map to iterate over. |
| 372 | * @bt: sbitmap to examine. This is either the breserved_tags member |
| 373 | * or the bitmap_tags member of struct blk_mq_tags. |
| 374 | * @fn: Pointer to the function that will be called for each started |
| 375 | * request. @fn will be called as follows: @fn(rq, @data, |
| 376 | * @reserved) where rq is a pointer to a request. Return true |
| 377 | * to continue iterating tags, false to stop. |
| 378 | * @data: Will be passed as second argument to @fn. |
| 379 | * @flags: BT_TAG_ITER_* |
| 380 | */ |
| 381 | static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt, |
| 382 | busy_tag_iter_fn *fn, void *data, unsigned int flags) |
| 383 | { |
| 384 | struct bt_tags_iter_data iter_data = { |
| 385 | .tags = tags, |
| 386 | .fn = fn, |
| 387 | .data = data, |
| 388 | .flags = flags, |
| 389 | }; |
| 390 | |
| 391 | if (tags->rqs) |
| 392 | sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data); |
| 393 | } |
| 394 | |
| 395 | static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags, |
| 396 | busy_tag_iter_fn *fn, void *priv, unsigned int flags) |
| 397 | { |
| 398 | WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED); |
| 399 | |
| 400 | if (tags->nr_reserved_tags) |
| 401 | bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, |
| 402 | flags | BT_TAG_ITER_RESERVED); |
| 403 | bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, flags); |
| 404 | } |
| 405 | |
| 406 | /** |
| 407 | * blk_mq_all_tag_iter - iterate over all requests in a tag map |
| 408 | * @tags: Tag map to iterate over. |
| 409 | * @fn: Pointer to the function that will be called for each |
| 410 | * request. @fn will be called as follows: @fn(rq, @priv, |
| 411 | * reserved) where rq is a pointer to a request. 'reserved' |
| 412 | * indicates whether or not @rq is a reserved request. Return |
| 413 | * true to continue iterating tags, false to stop. |
| 414 | * @priv: Will be passed as second argument to @fn. |
| 415 | * |
| 416 | * Caller has to pass the tag map from which requests are allocated. |
| 417 | */ |
| 418 | void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn, |
| 419 | void *priv) |
| 420 | { |
| 421 | __blk_mq_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS); |
| 422 | } |
| 423 | |
| 424 | /** |
| 425 | * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set |
| 426 | * @tagset: Tag set to iterate over. |
| 427 | * @fn: Pointer to the function that will be called for each started |
| 428 | * request. @fn will be called as follows: @fn(rq, @priv, |
| 429 | * reserved) where rq is a pointer to a request. 'reserved' |
| 430 | * indicates whether or not @rq is a reserved request. Return |
| 431 | * true to continue iterating tags, false to stop. |
| 432 | * @priv: Will be passed as second argument to @fn. |
| 433 | * |
| 434 | * We grab one request reference before calling @fn and release it after |
| 435 | * @fn returns. |
| 436 | */ |
| 437 | void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset, |
| 438 | busy_tag_iter_fn *fn, void *priv) |
| 439 | { |
| 440 | unsigned int flags = tagset->flags; |
| 441 | int i, nr_tags; |
| 442 | |
| 443 | nr_tags = blk_mq_is_shared_tags(flags) ? 1 : tagset->nr_hw_queues; |
| 444 | |
| 445 | for (i = 0; i < nr_tags; i++) { |
| 446 | if (tagset->tags && tagset->tags[i]) |
| 447 | __blk_mq_all_tag_iter(tagset->tags[i], fn, priv, |
| 448 | BT_TAG_ITER_STARTED); |
| 449 | } |
| 450 | } |
| 451 | EXPORT_SYMBOL(blk_mq_tagset_busy_iter); |
| 452 | |
| 453 | static bool blk_mq_tagset_count_completed_rqs(struct request *rq, void *data) |
| 454 | { |
| 455 | unsigned *count = data; |
| 456 | |
| 457 | if (blk_mq_request_completed(rq)) |
| 458 | (*count)++; |
| 459 | return true; |
| 460 | } |
| 461 | |
| 462 | /** |
| 463 | * blk_mq_tagset_wait_completed_request - Wait until all scheduled request |
| 464 | * completions have finished. |
| 465 | * @tagset: Tag set to drain completed request |
| 466 | * |
| 467 | * Note: This function has to be run after all IO queues are shutdown |
| 468 | */ |
| 469 | void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset) |
| 470 | { |
| 471 | while (true) { |
| 472 | unsigned count = 0; |
| 473 | |
| 474 | blk_mq_tagset_busy_iter(tagset, |
| 475 | blk_mq_tagset_count_completed_rqs, &count); |
| 476 | if (!count) |
| 477 | break; |
| 478 | msleep(5); |
| 479 | } |
| 480 | } |
| 481 | EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request); |
| 482 | |
| 483 | /** |
| 484 | * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag |
| 485 | * @q: Request queue to examine. |
| 486 | * @fn: Pointer to the function that will be called for each request |
| 487 | * on @q. @fn will be called as follows: @fn(hctx, rq, @priv, |
| 488 | * reserved) where rq is a pointer to a request and hctx points |
| 489 | * to the hardware queue associated with the request. 'reserved' |
| 490 | * indicates whether or not @rq is a reserved request. |
| 491 | * @priv: Will be passed as third argument to @fn. |
| 492 | * |
| 493 | * Note: if @q->tag_set is shared with other request queues then @fn will be |
| 494 | * called for all requests on all queues that share that tag set and not only |
| 495 | * for requests associated with @q. |
| 496 | */ |
| 497 | void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn, |
| 498 | void *priv) |
| 499 | { |
| 500 | /* |
| 501 | * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and hctx_table |
| 502 | * while the queue is frozen. So we can use q_usage_counter to avoid |
| 503 | * racing with it. |
| 504 | */ |
| 505 | if (!percpu_ref_tryget(&q->q_usage_counter)) |
| 506 | return; |
| 507 | |
| 508 | if (blk_mq_is_shared_tags(q->tag_set->flags)) { |
| 509 | struct blk_mq_tags *tags = q->tag_set->shared_tags; |
| 510 | struct sbitmap_queue *bresv = &tags->breserved_tags; |
| 511 | struct sbitmap_queue *btags = &tags->bitmap_tags; |
| 512 | |
| 513 | if (tags->nr_reserved_tags) |
| 514 | bt_for_each(NULL, q, bresv, fn, priv, true); |
| 515 | bt_for_each(NULL, q, btags, fn, priv, false); |
| 516 | } else { |
| 517 | struct blk_mq_hw_ctx *hctx; |
| 518 | unsigned long i; |
| 519 | |
| 520 | queue_for_each_hw_ctx(q, hctx, i) { |
| 521 | struct blk_mq_tags *tags = hctx->tags; |
| 522 | struct sbitmap_queue *bresv = &tags->breserved_tags; |
| 523 | struct sbitmap_queue *btags = &tags->bitmap_tags; |
| 524 | |
| 525 | /* |
| 526 | * If no software queues are currently mapped to this |
| 527 | * hardware queue, there's nothing to check |
| 528 | */ |
| 529 | if (!blk_mq_hw_queue_mapped(hctx)) |
| 530 | continue; |
| 531 | |
| 532 | if (tags->nr_reserved_tags) |
| 533 | bt_for_each(hctx, q, bresv, fn, priv, true); |
| 534 | bt_for_each(hctx, q, btags, fn, priv, false); |
| 535 | } |
| 536 | } |
| 537 | blk_queue_exit(q); |
| 538 | } |
| 539 | |
| 540 | static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth, |
| 541 | bool round_robin, int node) |
| 542 | { |
| 543 | return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL, |
| 544 | node); |
| 545 | } |
| 546 | |
| 547 | int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags, |
| 548 | struct sbitmap_queue *breserved_tags, |
| 549 | unsigned int queue_depth, unsigned int reserved, |
| 550 | int node, int alloc_policy) |
| 551 | { |
| 552 | unsigned int depth = queue_depth - reserved; |
| 553 | bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR; |
| 554 | |
| 555 | if (bt_alloc(bitmap_tags, depth, round_robin, node)) |
| 556 | return -ENOMEM; |
| 557 | if (bt_alloc(breserved_tags, reserved, round_robin, node)) |
| 558 | goto free_bitmap_tags; |
| 559 | |
| 560 | return 0; |
| 561 | |
| 562 | free_bitmap_tags: |
| 563 | sbitmap_queue_free(bitmap_tags); |
| 564 | return -ENOMEM; |
| 565 | } |
| 566 | |
| 567 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, |
| 568 | unsigned int reserved_tags, |
| 569 | int node, int alloc_policy) |
| 570 | { |
| 571 | struct blk_mq_tags *tags; |
| 572 | |
| 573 | if (total_tags > BLK_MQ_TAG_MAX) { |
| 574 | pr_err("blk-mq: tag depth too large\n"); |
| 575 | return NULL; |
| 576 | } |
| 577 | |
| 578 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); |
| 579 | if (!tags) |
| 580 | return NULL; |
| 581 | |
| 582 | tags->nr_tags = total_tags; |
| 583 | tags->nr_reserved_tags = reserved_tags; |
| 584 | spin_lock_init(&tags->lock); |
| 585 | |
| 586 | if (blk_mq_init_bitmaps(&tags->bitmap_tags, &tags->breserved_tags, |
| 587 | total_tags, reserved_tags, node, |
| 588 | alloc_policy) < 0) { |
| 589 | kfree(tags); |
| 590 | return NULL; |
| 591 | } |
| 592 | return tags; |
| 593 | } |
| 594 | |
| 595 | void blk_mq_free_tags(struct blk_mq_tags *tags) |
| 596 | { |
| 597 | sbitmap_queue_free(&tags->bitmap_tags); |
| 598 | sbitmap_queue_free(&tags->breserved_tags); |
| 599 | kfree(tags); |
| 600 | } |
| 601 | |
| 602 | int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, |
| 603 | struct blk_mq_tags **tagsptr, unsigned int tdepth, |
| 604 | bool can_grow) |
| 605 | { |
| 606 | struct blk_mq_tags *tags = *tagsptr; |
| 607 | |
| 608 | if (tdepth <= tags->nr_reserved_tags) |
| 609 | return -EINVAL; |
| 610 | |
| 611 | /* |
| 612 | * If we are allowed to grow beyond the original size, allocate |
| 613 | * a new set of tags before freeing the old one. |
| 614 | */ |
| 615 | if (tdepth > tags->nr_tags) { |
| 616 | struct blk_mq_tag_set *set = hctx->queue->tag_set; |
| 617 | struct blk_mq_tags *new; |
| 618 | |
| 619 | if (!can_grow) |
| 620 | return -EINVAL; |
| 621 | |
| 622 | /* |
| 623 | * We need some sort of upper limit, set it high enough that |
| 624 | * no valid use cases should require more. |
| 625 | */ |
| 626 | if (tdepth > MAX_SCHED_RQ) |
| 627 | return -EINVAL; |
| 628 | |
| 629 | /* |
| 630 | * Only the sbitmap needs resizing since we allocated the max |
| 631 | * initially. |
| 632 | */ |
| 633 | if (blk_mq_is_shared_tags(set->flags)) |
| 634 | return 0; |
| 635 | |
| 636 | new = blk_mq_alloc_map_and_rqs(set, hctx->queue_num, tdepth); |
| 637 | if (!new) |
| 638 | return -ENOMEM; |
| 639 | |
| 640 | blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num); |
| 641 | *tagsptr = new; |
| 642 | } else { |
| 643 | /* |
| 644 | * Don't need (or can't) update reserved tags here, they |
| 645 | * remain static and should never need resizing. |
| 646 | */ |
| 647 | sbitmap_queue_resize(&tags->bitmap_tags, |
| 648 | tdepth - tags->nr_reserved_tags); |
| 649 | } |
| 650 | |
| 651 | return 0; |
| 652 | } |
| 653 | |
| 654 | void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size) |
| 655 | { |
| 656 | struct blk_mq_tags *tags = set->shared_tags; |
| 657 | |
| 658 | sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags); |
| 659 | } |
| 660 | |
| 661 | void blk_mq_tag_update_sched_shared_tags(struct request_queue *q) |
| 662 | { |
| 663 | sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags, |
| 664 | q->nr_requests - q->tag_set->reserved_tags); |
| 665 | } |
| 666 | |
| 667 | /** |
| 668 | * blk_mq_unique_tag() - return a tag that is unique queue-wide |
| 669 | * @rq: request for which to compute a unique tag |
| 670 | * |
| 671 | * The tag field in struct request is unique per hardware queue but not over |
| 672 | * all hardware queues. Hence this function that returns a tag with the |
| 673 | * hardware context index in the upper bits and the per hardware queue tag in |
| 674 | * the lower bits. |
| 675 | * |
| 676 | * Note: When called for a request that is queued on a non-multiqueue request |
| 677 | * queue, the hardware context index is set to zero. |
| 678 | */ |
| 679 | u32 blk_mq_unique_tag(struct request *rq) |
| 680 | { |
| 681 | return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) | |
| 682 | (rq->tag & BLK_MQ_UNIQUE_TAG_MASK); |
| 683 | } |
| 684 | EXPORT_SYMBOL(blk_mq_unique_tag); |