| 1 | /* |
| 2 | * Block multiqueue core code |
| 3 | * |
| 4 | * Copyright (C) 2013-2014 Jens Axboe |
| 5 | * Copyright (C) 2013-2014 Christoph Hellwig |
| 6 | */ |
| 7 | #include <linux/kernel.h> |
| 8 | #include <linux/module.h> |
| 9 | #include <linux/backing-dev.h> |
| 10 | #include <linux/bio.h> |
| 11 | #include <linux/blkdev.h> |
| 12 | #include <linux/mm.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/workqueue.h> |
| 16 | #include <linux/smp.h> |
| 17 | #include <linux/llist.h> |
| 18 | #include <linux/list_sort.h> |
| 19 | #include <linux/cpu.h> |
| 20 | #include <linux/cache.h> |
| 21 | #include <linux/sched/sysctl.h> |
| 22 | #include <linux/delay.h> |
| 23 | #include <linux/crash_dump.h> |
| 24 | |
| 25 | #include <trace/events/block.h> |
| 26 | |
| 27 | #include <linux/blk-mq.h> |
| 28 | #include "blk.h" |
| 29 | #include "blk-mq.h" |
| 30 | #include "blk-mq-tag.h" |
| 31 | |
| 32 | static DEFINE_MUTEX(all_q_mutex); |
| 33 | static LIST_HEAD(all_q_list); |
| 34 | |
| 35 | static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx); |
| 36 | |
| 37 | /* |
| 38 | * Check if any of the ctx's have pending work in this hardware queue |
| 39 | */ |
| 40 | static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) |
| 41 | { |
| 42 | unsigned int i; |
| 43 | |
| 44 | for (i = 0; i < hctx->ctx_map.map_size; i++) |
| 45 | if (hctx->ctx_map.map[i].word) |
| 46 | return true; |
| 47 | |
| 48 | return false; |
| 49 | } |
| 50 | |
| 51 | static inline struct blk_align_bitmap *get_bm(struct blk_mq_hw_ctx *hctx, |
| 52 | struct blk_mq_ctx *ctx) |
| 53 | { |
| 54 | return &hctx->ctx_map.map[ctx->index_hw / hctx->ctx_map.bits_per_word]; |
| 55 | } |
| 56 | |
| 57 | #define CTX_TO_BIT(hctx, ctx) \ |
| 58 | ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1)) |
| 59 | |
| 60 | /* |
| 61 | * Mark this ctx as having pending work in this hardware queue |
| 62 | */ |
| 63 | static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, |
| 64 | struct blk_mq_ctx *ctx) |
| 65 | { |
| 66 | struct blk_align_bitmap *bm = get_bm(hctx, ctx); |
| 67 | |
| 68 | if (!test_bit(CTX_TO_BIT(hctx, ctx), &bm->word)) |
| 69 | set_bit(CTX_TO_BIT(hctx, ctx), &bm->word); |
| 70 | } |
| 71 | |
| 72 | static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, |
| 73 | struct blk_mq_ctx *ctx) |
| 74 | { |
| 75 | struct blk_align_bitmap *bm = get_bm(hctx, ctx); |
| 76 | |
| 77 | clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word); |
| 78 | } |
| 79 | |
| 80 | static int blk_mq_queue_enter(struct request_queue *q) |
| 81 | { |
| 82 | while (true) { |
| 83 | int ret; |
| 84 | |
| 85 | if (percpu_ref_tryget_live(&q->mq_usage_counter)) |
| 86 | return 0; |
| 87 | |
| 88 | ret = wait_event_interruptible(q->mq_freeze_wq, |
| 89 | !q->mq_freeze_depth || blk_queue_dying(q)); |
| 90 | if (blk_queue_dying(q)) |
| 91 | return -ENODEV; |
| 92 | if (ret) |
| 93 | return ret; |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | static void blk_mq_queue_exit(struct request_queue *q) |
| 98 | { |
| 99 | percpu_ref_put(&q->mq_usage_counter); |
| 100 | } |
| 101 | |
| 102 | static void blk_mq_usage_counter_release(struct percpu_ref *ref) |
| 103 | { |
| 104 | struct request_queue *q = |
| 105 | container_of(ref, struct request_queue, mq_usage_counter); |
| 106 | |
| 107 | wake_up_all(&q->mq_freeze_wq); |
| 108 | } |
| 109 | |
| 110 | static void blk_mq_freeze_queue_start(struct request_queue *q) |
| 111 | { |
| 112 | bool freeze; |
| 113 | |
| 114 | spin_lock_irq(q->queue_lock); |
| 115 | freeze = !q->mq_freeze_depth++; |
| 116 | spin_unlock_irq(q->queue_lock); |
| 117 | |
| 118 | if (freeze) { |
| 119 | percpu_ref_kill(&q->mq_usage_counter); |
| 120 | blk_mq_run_queues(q, false); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | static void blk_mq_freeze_queue_wait(struct request_queue *q) |
| 125 | { |
| 126 | wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter)); |
| 127 | } |
| 128 | |
| 129 | /* |
| 130 | * Guarantee no request is in use, so we can change any data structure of |
| 131 | * the queue afterward. |
| 132 | */ |
| 133 | void blk_mq_freeze_queue(struct request_queue *q) |
| 134 | { |
| 135 | blk_mq_freeze_queue_start(q); |
| 136 | blk_mq_freeze_queue_wait(q); |
| 137 | } |
| 138 | |
| 139 | static void blk_mq_unfreeze_queue(struct request_queue *q) |
| 140 | { |
| 141 | bool wake; |
| 142 | |
| 143 | spin_lock_irq(q->queue_lock); |
| 144 | wake = !--q->mq_freeze_depth; |
| 145 | WARN_ON_ONCE(q->mq_freeze_depth < 0); |
| 146 | spin_unlock_irq(q->queue_lock); |
| 147 | if (wake) { |
| 148 | percpu_ref_reinit(&q->mq_usage_counter); |
| 149 | wake_up_all(&q->mq_freeze_wq); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) |
| 154 | { |
| 155 | return blk_mq_has_free_tags(hctx->tags); |
| 156 | } |
| 157 | EXPORT_SYMBOL(blk_mq_can_queue); |
| 158 | |
| 159 | static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, |
| 160 | struct request *rq, unsigned int rw_flags) |
| 161 | { |
| 162 | if (blk_queue_io_stat(q)) |
| 163 | rw_flags |= REQ_IO_STAT; |
| 164 | |
| 165 | INIT_LIST_HEAD(&rq->queuelist); |
| 166 | /* csd/requeue_work/fifo_time is initialized before use */ |
| 167 | rq->q = q; |
| 168 | rq->mq_ctx = ctx; |
| 169 | rq->cmd_flags |= rw_flags; |
| 170 | /* do not touch atomic flags, it needs atomic ops against the timer */ |
| 171 | rq->cpu = -1; |
| 172 | INIT_HLIST_NODE(&rq->hash); |
| 173 | RB_CLEAR_NODE(&rq->rb_node); |
| 174 | rq->rq_disk = NULL; |
| 175 | rq->part = NULL; |
| 176 | rq->start_time = jiffies; |
| 177 | #ifdef CONFIG_BLK_CGROUP |
| 178 | rq->rl = NULL; |
| 179 | set_start_time_ns(rq); |
| 180 | rq->io_start_time_ns = 0; |
| 181 | #endif |
| 182 | rq->nr_phys_segments = 0; |
| 183 | #if defined(CONFIG_BLK_DEV_INTEGRITY) |
| 184 | rq->nr_integrity_segments = 0; |
| 185 | #endif |
| 186 | rq->special = NULL; |
| 187 | /* tag was already set */ |
| 188 | rq->errors = 0; |
| 189 | |
| 190 | rq->cmd = rq->__cmd; |
| 191 | |
| 192 | rq->extra_len = 0; |
| 193 | rq->sense_len = 0; |
| 194 | rq->resid_len = 0; |
| 195 | rq->sense = NULL; |
| 196 | |
| 197 | INIT_LIST_HEAD(&rq->timeout_list); |
| 198 | rq->timeout = 0; |
| 199 | |
| 200 | rq->end_io = NULL; |
| 201 | rq->end_io_data = NULL; |
| 202 | rq->next_rq = NULL; |
| 203 | |
| 204 | ctx->rq_dispatched[rw_is_sync(rw_flags)]++; |
| 205 | } |
| 206 | |
| 207 | static struct request * |
| 208 | __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) |
| 209 | { |
| 210 | struct request *rq; |
| 211 | unsigned int tag; |
| 212 | |
| 213 | tag = blk_mq_get_tag(data); |
| 214 | if (tag != BLK_MQ_TAG_FAIL) { |
| 215 | rq = data->hctx->tags->rqs[tag]; |
| 216 | |
| 217 | if (blk_mq_tag_busy(data->hctx)) { |
| 218 | rq->cmd_flags = REQ_MQ_INFLIGHT; |
| 219 | atomic_inc(&data->hctx->nr_active); |
| 220 | } |
| 221 | |
| 222 | rq->tag = tag; |
| 223 | blk_mq_rq_ctx_init(data->q, data->ctx, rq, rw); |
| 224 | return rq; |
| 225 | } |
| 226 | |
| 227 | return NULL; |
| 228 | } |
| 229 | |
| 230 | struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, |
| 231 | bool reserved) |
| 232 | { |
| 233 | struct blk_mq_ctx *ctx; |
| 234 | struct blk_mq_hw_ctx *hctx; |
| 235 | struct request *rq; |
| 236 | struct blk_mq_alloc_data alloc_data; |
| 237 | int ret; |
| 238 | |
| 239 | ret = blk_mq_queue_enter(q); |
| 240 | if (ret) |
| 241 | return ERR_PTR(ret); |
| 242 | |
| 243 | ctx = blk_mq_get_ctx(q); |
| 244 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 245 | blk_mq_set_alloc_data(&alloc_data, q, gfp & ~__GFP_WAIT, |
| 246 | reserved, ctx, hctx); |
| 247 | |
| 248 | rq = __blk_mq_alloc_request(&alloc_data, rw); |
| 249 | if (!rq && (gfp & __GFP_WAIT)) { |
| 250 | __blk_mq_run_hw_queue(hctx); |
| 251 | blk_mq_put_ctx(ctx); |
| 252 | |
| 253 | ctx = blk_mq_get_ctx(q); |
| 254 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 255 | blk_mq_set_alloc_data(&alloc_data, q, gfp, reserved, ctx, |
| 256 | hctx); |
| 257 | rq = __blk_mq_alloc_request(&alloc_data, rw); |
| 258 | ctx = alloc_data.ctx; |
| 259 | } |
| 260 | blk_mq_put_ctx(ctx); |
| 261 | if (!rq) { |
| 262 | blk_mq_queue_exit(q); |
| 263 | return ERR_PTR(-EWOULDBLOCK); |
| 264 | } |
| 265 | return rq; |
| 266 | } |
| 267 | EXPORT_SYMBOL(blk_mq_alloc_request); |
| 268 | |
| 269 | static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, |
| 270 | struct blk_mq_ctx *ctx, struct request *rq) |
| 271 | { |
| 272 | const int tag = rq->tag; |
| 273 | struct request_queue *q = rq->q; |
| 274 | |
| 275 | if (rq->cmd_flags & REQ_MQ_INFLIGHT) |
| 276 | atomic_dec(&hctx->nr_active); |
| 277 | rq->cmd_flags = 0; |
| 278 | |
| 279 | clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| 280 | blk_mq_put_tag(hctx, tag, &ctx->last_tag); |
| 281 | blk_mq_queue_exit(q); |
| 282 | } |
| 283 | |
| 284 | void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *hctx, struct request *rq) |
| 285 | { |
| 286 | struct blk_mq_ctx *ctx = rq->mq_ctx; |
| 287 | |
| 288 | ctx->rq_completed[rq_is_sync(rq)]++; |
| 289 | __blk_mq_free_request(hctx, ctx, rq); |
| 290 | |
| 291 | } |
| 292 | EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request); |
| 293 | |
| 294 | void blk_mq_free_request(struct request *rq) |
| 295 | { |
| 296 | struct blk_mq_hw_ctx *hctx; |
| 297 | struct request_queue *q = rq->q; |
| 298 | |
| 299 | hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu); |
| 300 | blk_mq_free_hctx_request(hctx, rq); |
| 301 | } |
| 302 | EXPORT_SYMBOL_GPL(blk_mq_free_request); |
| 303 | |
| 304 | inline void __blk_mq_end_request(struct request *rq, int error) |
| 305 | { |
| 306 | blk_account_io_done(rq); |
| 307 | |
| 308 | if (rq->end_io) { |
| 309 | rq->end_io(rq, error); |
| 310 | } else { |
| 311 | if (unlikely(blk_bidi_rq(rq))) |
| 312 | blk_mq_free_request(rq->next_rq); |
| 313 | blk_mq_free_request(rq); |
| 314 | } |
| 315 | } |
| 316 | EXPORT_SYMBOL(__blk_mq_end_request); |
| 317 | |
| 318 | void blk_mq_end_request(struct request *rq, int error) |
| 319 | { |
| 320 | if (blk_update_request(rq, error, blk_rq_bytes(rq))) |
| 321 | BUG(); |
| 322 | __blk_mq_end_request(rq, error); |
| 323 | } |
| 324 | EXPORT_SYMBOL(blk_mq_end_request); |
| 325 | |
| 326 | static void __blk_mq_complete_request_remote(void *data) |
| 327 | { |
| 328 | struct request *rq = data; |
| 329 | |
| 330 | rq->q->softirq_done_fn(rq); |
| 331 | } |
| 332 | |
| 333 | static void blk_mq_ipi_complete_request(struct request *rq) |
| 334 | { |
| 335 | struct blk_mq_ctx *ctx = rq->mq_ctx; |
| 336 | bool shared = false; |
| 337 | int cpu; |
| 338 | |
| 339 | if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { |
| 340 | rq->q->softirq_done_fn(rq); |
| 341 | return; |
| 342 | } |
| 343 | |
| 344 | cpu = get_cpu(); |
| 345 | if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) |
| 346 | shared = cpus_share_cache(cpu, ctx->cpu); |
| 347 | |
| 348 | if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { |
| 349 | rq->csd.func = __blk_mq_complete_request_remote; |
| 350 | rq->csd.info = rq; |
| 351 | rq->csd.flags = 0; |
| 352 | smp_call_function_single_async(ctx->cpu, &rq->csd); |
| 353 | } else { |
| 354 | rq->q->softirq_done_fn(rq); |
| 355 | } |
| 356 | put_cpu(); |
| 357 | } |
| 358 | |
| 359 | void __blk_mq_complete_request(struct request *rq) |
| 360 | { |
| 361 | struct request_queue *q = rq->q; |
| 362 | |
| 363 | if (!q->softirq_done_fn) |
| 364 | blk_mq_end_request(rq, rq->errors); |
| 365 | else |
| 366 | blk_mq_ipi_complete_request(rq); |
| 367 | } |
| 368 | |
| 369 | /** |
| 370 | * blk_mq_complete_request - end I/O on a request |
| 371 | * @rq: the request being processed |
| 372 | * |
| 373 | * Description: |
| 374 | * Ends all I/O on a request. It does not handle partial completions. |
| 375 | * The actual completion happens out-of-order, through a IPI handler. |
| 376 | **/ |
| 377 | void blk_mq_complete_request(struct request *rq) |
| 378 | { |
| 379 | struct request_queue *q = rq->q; |
| 380 | |
| 381 | if (unlikely(blk_should_fake_timeout(q))) |
| 382 | return; |
| 383 | if (!blk_mark_rq_complete(rq)) |
| 384 | __blk_mq_complete_request(rq); |
| 385 | } |
| 386 | EXPORT_SYMBOL(blk_mq_complete_request); |
| 387 | |
| 388 | void blk_mq_start_request(struct request *rq) |
| 389 | { |
| 390 | struct request_queue *q = rq->q; |
| 391 | |
| 392 | trace_block_rq_issue(q, rq); |
| 393 | |
| 394 | rq->resid_len = blk_rq_bytes(rq); |
| 395 | if (unlikely(blk_bidi_rq(rq))) |
| 396 | rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq); |
| 397 | |
| 398 | blk_add_timer(rq); |
| 399 | |
| 400 | /* |
| 401 | * Ensure that ->deadline is visible before set the started |
| 402 | * flag and clear the completed flag. |
| 403 | */ |
| 404 | smp_mb__before_atomic(); |
| 405 | |
| 406 | /* |
| 407 | * Mark us as started and clear complete. Complete might have been |
| 408 | * set if requeue raced with timeout, which then marked it as |
| 409 | * complete. So be sure to clear complete again when we start |
| 410 | * the request, otherwise we'll ignore the completion event. |
| 411 | */ |
| 412 | if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) |
| 413 | set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| 414 | if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) |
| 415 | clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); |
| 416 | |
| 417 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
| 418 | /* |
| 419 | * Make sure space for the drain appears. We know we can do |
| 420 | * this because max_hw_segments has been adjusted to be one |
| 421 | * fewer than the device can handle. |
| 422 | */ |
| 423 | rq->nr_phys_segments++; |
| 424 | } |
| 425 | } |
| 426 | EXPORT_SYMBOL(blk_mq_start_request); |
| 427 | |
| 428 | static void __blk_mq_requeue_request(struct request *rq) |
| 429 | { |
| 430 | struct request_queue *q = rq->q; |
| 431 | |
| 432 | trace_block_rq_requeue(q, rq); |
| 433 | |
| 434 | if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { |
| 435 | if (q->dma_drain_size && blk_rq_bytes(rq)) |
| 436 | rq->nr_phys_segments--; |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | void blk_mq_requeue_request(struct request *rq) |
| 441 | { |
| 442 | __blk_mq_requeue_request(rq); |
| 443 | |
| 444 | BUG_ON(blk_queued_rq(rq)); |
| 445 | blk_mq_add_to_requeue_list(rq, true); |
| 446 | } |
| 447 | EXPORT_SYMBOL(blk_mq_requeue_request); |
| 448 | |
| 449 | static void blk_mq_requeue_work(struct work_struct *work) |
| 450 | { |
| 451 | struct request_queue *q = |
| 452 | container_of(work, struct request_queue, requeue_work); |
| 453 | LIST_HEAD(rq_list); |
| 454 | struct request *rq, *next; |
| 455 | unsigned long flags; |
| 456 | |
| 457 | spin_lock_irqsave(&q->requeue_lock, flags); |
| 458 | list_splice_init(&q->requeue_list, &rq_list); |
| 459 | spin_unlock_irqrestore(&q->requeue_lock, flags); |
| 460 | |
| 461 | list_for_each_entry_safe(rq, next, &rq_list, queuelist) { |
| 462 | if (!(rq->cmd_flags & REQ_SOFTBARRIER)) |
| 463 | continue; |
| 464 | |
| 465 | rq->cmd_flags &= ~REQ_SOFTBARRIER; |
| 466 | list_del_init(&rq->queuelist); |
| 467 | blk_mq_insert_request(rq, true, false, false); |
| 468 | } |
| 469 | |
| 470 | while (!list_empty(&rq_list)) { |
| 471 | rq = list_entry(rq_list.next, struct request, queuelist); |
| 472 | list_del_init(&rq->queuelist); |
| 473 | blk_mq_insert_request(rq, false, false, false); |
| 474 | } |
| 475 | |
| 476 | /* |
| 477 | * Use the start variant of queue running here, so that running |
| 478 | * the requeue work will kick stopped queues. |
| 479 | */ |
| 480 | blk_mq_start_hw_queues(q); |
| 481 | } |
| 482 | |
| 483 | void blk_mq_add_to_requeue_list(struct request *rq, bool at_head) |
| 484 | { |
| 485 | struct request_queue *q = rq->q; |
| 486 | unsigned long flags; |
| 487 | |
| 488 | /* |
| 489 | * We abuse this flag that is otherwise used by the I/O scheduler to |
| 490 | * request head insertation from the workqueue. |
| 491 | */ |
| 492 | BUG_ON(rq->cmd_flags & REQ_SOFTBARRIER); |
| 493 | |
| 494 | spin_lock_irqsave(&q->requeue_lock, flags); |
| 495 | if (at_head) { |
| 496 | rq->cmd_flags |= REQ_SOFTBARRIER; |
| 497 | list_add(&rq->queuelist, &q->requeue_list); |
| 498 | } else { |
| 499 | list_add_tail(&rq->queuelist, &q->requeue_list); |
| 500 | } |
| 501 | spin_unlock_irqrestore(&q->requeue_lock, flags); |
| 502 | } |
| 503 | EXPORT_SYMBOL(blk_mq_add_to_requeue_list); |
| 504 | |
| 505 | void blk_mq_kick_requeue_list(struct request_queue *q) |
| 506 | { |
| 507 | kblockd_schedule_work(&q->requeue_work); |
| 508 | } |
| 509 | EXPORT_SYMBOL(blk_mq_kick_requeue_list); |
| 510 | |
| 511 | static inline bool is_flush_request(struct request *rq, |
| 512 | struct blk_flush_queue *fq, unsigned int tag) |
| 513 | { |
| 514 | return ((rq->cmd_flags & REQ_FLUSH_SEQ) && |
| 515 | fq->flush_rq->tag == tag); |
| 516 | } |
| 517 | |
| 518 | struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) |
| 519 | { |
| 520 | struct request *rq = tags->rqs[tag]; |
| 521 | /* mq_ctx of flush rq is always cloned from the corresponding req */ |
| 522 | struct blk_flush_queue *fq = blk_get_flush_queue(rq->q, rq->mq_ctx); |
| 523 | |
| 524 | if (!is_flush_request(rq, fq, tag)) |
| 525 | return rq; |
| 526 | |
| 527 | return fq->flush_rq; |
| 528 | } |
| 529 | EXPORT_SYMBOL(blk_mq_tag_to_rq); |
| 530 | |
| 531 | struct blk_mq_timeout_data { |
| 532 | unsigned long next; |
| 533 | unsigned int next_set; |
| 534 | }; |
| 535 | |
| 536 | void blk_mq_rq_timed_out(struct request *req, bool reserved) |
| 537 | { |
| 538 | struct blk_mq_ops *ops = req->q->mq_ops; |
| 539 | enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; |
| 540 | |
| 541 | /* |
| 542 | * We know that complete is set at this point. If STARTED isn't set |
| 543 | * anymore, then the request isn't active and the "timeout" should |
| 544 | * just be ignored. This can happen due to the bitflag ordering. |
| 545 | * Timeout first checks if STARTED is set, and if it is, assumes |
| 546 | * the request is active. But if we race with completion, then |
| 547 | * we both flags will get cleared. So check here again, and ignore |
| 548 | * a timeout event with a request that isn't active. |
| 549 | */ |
| 550 | if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags)) |
| 551 | return; |
| 552 | |
| 553 | if (ops->timeout) |
| 554 | ret = ops->timeout(req, reserved); |
| 555 | |
| 556 | switch (ret) { |
| 557 | case BLK_EH_HANDLED: |
| 558 | __blk_mq_complete_request(req); |
| 559 | break; |
| 560 | case BLK_EH_RESET_TIMER: |
| 561 | blk_add_timer(req); |
| 562 | blk_clear_rq_complete(req); |
| 563 | break; |
| 564 | case BLK_EH_NOT_HANDLED: |
| 565 | break; |
| 566 | default: |
| 567 | printk(KERN_ERR "block: bad eh return: %d\n", ret); |
| 568 | break; |
| 569 | } |
| 570 | } |
| 571 | |
| 572 | static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, |
| 573 | struct request *rq, void *priv, bool reserved) |
| 574 | { |
| 575 | struct blk_mq_timeout_data *data = priv; |
| 576 | |
| 577 | if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) |
| 578 | return; |
| 579 | |
| 580 | if (time_after_eq(jiffies, rq->deadline)) { |
| 581 | if (!blk_mark_rq_complete(rq)) |
| 582 | blk_mq_rq_timed_out(rq, reserved); |
| 583 | } else if (!data->next_set || time_after(data->next, rq->deadline)) { |
| 584 | data->next = rq->deadline; |
| 585 | data->next_set = 1; |
| 586 | } |
| 587 | } |
| 588 | |
| 589 | static void blk_mq_rq_timer(unsigned long priv) |
| 590 | { |
| 591 | struct request_queue *q = (struct request_queue *)priv; |
| 592 | struct blk_mq_timeout_data data = { |
| 593 | .next = 0, |
| 594 | .next_set = 0, |
| 595 | }; |
| 596 | struct blk_mq_hw_ctx *hctx; |
| 597 | int i; |
| 598 | |
| 599 | queue_for_each_hw_ctx(q, hctx, i) { |
| 600 | /* |
| 601 | * If not software queues are currently mapped to this |
| 602 | * hardware queue, there's nothing to check |
| 603 | */ |
| 604 | if (!blk_mq_hw_queue_mapped(hctx)) |
| 605 | continue; |
| 606 | |
| 607 | blk_mq_tag_busy_iter(hctx, blk_mq_check_expired, &data); |
| 608 | } |
| 609 | |
| 610 | if (data.next_set) { |
| 611 | data.next = blk_rq_timeout(round_jiffies_up(data.next)); |
| 612 | mod_timer(&q->timeout, data.next); |
| 613 | } else { |
| 614 | queue_for_each_hw_ctx(q, hctx, i) |
| 615 | blk_mq_tag_idle(hctx); |
| 616 | } |
| 617 | } |
| 618 | |
| 619 | /* |
| 620 | * Reverse check our software queue for entries that we could potentially |
| 621 | * merge with. Currently includes a hand-wavy stop count of 8, to not spend |
| 622 | * too much time checking for merges. |
| 623 | */ |
| 624 | static bool blk_mq_attempt_merge(struct request_queue *q, |
| 625 | struct blk_mq_ctx *ctx, struct bio *bio) |
| 626 | { |
| 627 | struct request *rq; |
| 628 | int checked = 8; |
| 629 | |
| 630 | list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { |
| 631 | int el_ret; |
| 632 | |
| 633 | if (!checked--) |
| 634 | break; |
| 635 | |
| 636 | if (!blk_rq_merge_ok(rq, bio)) |
| 637 | continue; |
| 638 | |
| 639 | el_ret = blk_try_merge(rq, bio); |
| 640 | if (el_ret == ELEVATOR_BACK_MERGE) { |
| 641 | if (bio_attempt_back_merge(q, rq, bio)) { |
| 642 | ctx->rq_merged++; |
| 643 | return true; |
| 644 | } |
| 645 | break; |
| 646 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { |
| 647 | if (bio_attempt_front_merge(q, rq, bio)) { |
| 648 | ctx->rq_merged++; |
| 649 | return true; |
| 650 | } |
| 651 | break; |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | return false; |
| 656 | } |
| 657 | |
| 658 | /* |
| 659 | * Process software queues that have been marked busy, splicing them |
| 660 | * to the for-dispatch |
| 661 | */ |
| 662 | static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) |
| 663 | { |
| 664 | struct blk_mq_ctx *ctx; |
| 665 | int i; |
| 666 | |
| 667 | for (i = 0; i < hctx->ctx_map.map_size; i++) { |
| 668 | struct blk_align_bitmap *bm = &hctx->ctx_map.map[i]; |
| 669 | unsigned int off, bit; |
| 670 | |
| 671 | if (!bm->word) |
| 672 | continue; |
| 673 | |
| 674 | bit = 0; |
| 675 | off = i * hctx->ctx_map.bits_per_word; |
| 676 | do { |
| 677 | bit = find_next_bit(&bm->word, bm->depth, bit); |
| 678 | if (bit >= bm->depth) |
| 679 | break; |
| 680 | |
| 681 | ctx = hctx->ctxs[bit + off]; |
| 682 | clear_bit(bit, &bm->word); |
| 683 | spin_lock(&ctx->lock); |
| 684 | list_splice_tail_init(&ctx->rq_list, list); |
| 685 | spin_unlock(&ctx->lock); |
| 686 | |
| 687 | bit++; |
| 688 | } while (1); |
| 689 | } |
| 690 | } |
| 691 | |
| 692 | /* |
| 693 | * Run this hardware queue, pulling any software queues mapped to it in. |
| 694 | * Note that this function currently has various problems around ordering |
| 695 | * of IO. In particular, we'd like FIFO behaviour on handling existing |
| 696 | * items on the hctx->dispatch list. Ignore that for now. |
| 697 | */ |
| 698 | static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) |
| 699 | { |
| 700 | struct request_queue *q = hctx->queue; |
| 701 | struct request *rq; |
| 702 | LIST_HEAD(rq_list); |
| 703 | LIST_HEAD(driver_list); |
| 704 | struct list_head *dptr; |
| 705 | int queued; |
| 706 | |
| 707 | WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)); |
| 708 | |
| 709 | if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state))) |
| 710 | return; |
| 711 | |
| 712 | hctx->run++; |
| 713 | |
| 714 | /* |
| 715 | * Touch any software queue that has pending entries. |
| 716 | */ |
| 717 | flush_busy_ctxs(hctx, &rq_list); |
| 718 | |
| 719 | /* |
| 720 | * If we have previous entries on our dispatch list, grab them |
| 721 | * and stuff them at the front for more fair dispatch. |
| 722 | */ |
| 723 | if (!list_empty_careful(&hctx->dispatch)) { |
| 724 | spin_lock(&hctx->lock); |
| 725 | if (!list_empty(&hctx->dispatch)) |
| 726 | list_splice_init(&hctx->dispatch, &rq_list); |
| 727 | spin_unlock(&hctx->lock); |
| 728 | } |
| 729 | |
| 730 | /* |
| 731 | * Start off with dptr being NULL, so we start the first request |
| 732 | * immediately, even if we have more pending. |
| 733 | */ |
| 734 | dptr = NULL; |
| 735 | |
| 736 | /* |
| 737 | * Now process all the entries, sending them to the driver. |
| 738 | */ |
| 739 | queued = 0; |
| 740 | while (!list_empty(&rq_list)) { |
| 741 | struct blk_mq_queue_data bd; |
| 742 | int ret; |
| 743 | |
| 744 | rq = list_first_entry(&rq_list, struct request, queuelist); |
| 745 | list_del_init(&rq->queuelist); |
| 746 | |
| 747 | bd.rq = rq; |
| 748 | bd.list = dptr; |
| 749 | bd.last = list_empty(&rq_list); |
| 750 | |
| 751 | ret = q->mq_ops->queue_rq(hctx, &bd); |
| 752 | switch (ret) { |
| 753 | case BLK_MQ_RQ_QUEUE_OK: |
| 754 | queued++; |
| 755 | continue; |
| 756 | case BLK_MQ_RQ_QUEUE_BUSY: |
| 757 | list_add(&rq->queuelist, &rq_list); |
| 758 | __blk_mq_requeue_request(rq); |
| 759 | break; |
| 760 | default: |
| 761 | pr_err("blk-mq: bad return on queue: %d\n", ret); |
| 762 | case BLK_MQ_RQ_QUEUE_ERROR: |
| 763 | rq->errors = -EIO; |
| 764 | blk_mq_end_request(rq, rq->errors); |
| 765 | break; |
| 766 | } |
| 767 | |
| 768 | if (ret == BLK_MQ_RQ_QUEUE_BUSY) |
| 769 | break; |
| 770 | |
| 771 | /* |
| 772 | * We've done the first request. If we have more than 1 |
| 773 | * left in the list, set dptr to defer issue. |
| 774 | */ |
| 775 | if (!dptr && rq_list.next != rq_list.prev) |
| 776 | dptr = &driver_list; |
| 777 | } |
| 778 | |
| 779 | if (!queued) |
| 780 | hctx->dispatched[0]++; |
| 781 | else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1))) |
| 782 | hctx->dispatched[ilog2(queued) + 1]++; |
| 783 | |
| 784 | /* |
| 785 | * Any items that need requeuing? Stuff them into hctx->dispatch, |
| 786 | * that is where we will continue on next queue run. |
| 787 | */ |
| 788 | if (!list_empty(&rq_list)) { |
| 789 | spin_lock(&hctx->lock); |
| 790 | list_splice(&rq_list, &hctx->dispatch); |
| 791 | spin_unlock(&hctx->lock); |
| 792 | } |
| 793 | } |
| 794 | |
| 795 | /* |
| 796 | * It'd be great if the workqueue API had a way to pass |
| 797 | * in a mask and had some smarts for more clever placement. |
| 798 | * For now we just round-robin here, switching for every |
| 799 | * BLK_MQ_CPU_WORK_BATCH queued items. |
| 800 | */ |
| 801 | static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) |
| 802 | { |
| 803 | if (hctx->queue->nr_hw_queues == 1) |
| 804 | return WORK_CPU_UNBOUND; |
| 805 | |
| 806 | if (--hctx->next_cpu_batch <= 0) { |
| 807 | int cpu = hctx->next_cpu, next_cpu; |
| 808 | |
| 809 | next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask); |
| 810 | if (next_cpu >= nr_cpu_ids) |
| 811 | next_cpu = cpumask_first(hctx->cpumask); |
| 812 | |
| 813 | hctx->next_cpu = next_cpu; |
| 814 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| 815 | |
| 816 | return cpu; |
| 817 | } |
| 818 | |
| 819 | return hctx->next_cpu; |
| 820 | } |
| 821 | |
| 822 | void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) |
| 823 | { |
| 824 | if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state) || |
| 825 | !blk_mq_hw_queue_mapped(hctx))) |
| 826 | return; |
| 827 | |
| 828 | if (!async) { |
| 829 | int cpu = get_cpu(); |
| 830 | if (cpumask_test_cpu(cpu, hctx->cpumask)) { |
| 831 | __blk_mq_run_hw_queue(hctx); |
| 832 | put_cpu(); |
| 833 | return; |
| 834 | } |
| 835 | |
| 836 | put_cpu(); |
| 837 | } |
| 838 | |
| 839 | kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| 840 | &hctx->run_work, 0); |
| 841 | } |
| 842 | |
| 843 | void blk_mq_run_queues(struct request_queue *q, bool async) |
| 844 | { |
| 845 | struct blk_mq_hw_ctx *hctx; |
| 846 | int i; |
| 847 | |
| 848 | queue_for_each_hw_ctx(q, hctx, i) { |
| 849 | if ((!blk_mq_hctx_has_pending(hctx) && |
| 850 | list_empty_careful(&hctx->dispatch)) || |
| 851 | test_bit(BLK_MQ_S_STOPPED, &hctx->state)) |
| 852 | continue; |
| 853 | |
| 854 | blk_mq_run_hw_queue(hctx, async); |
| 855 | } |
| 856 | } |
| 857 | EXPORT_SYMBOL(blk_mq_run_queues); |
| 858 | |
| 859 | void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) |
| 860 | { |
| 861 | cancel_delayed_work(&hctx->run_work); |
| 862 | cancel_delayed_work(&hctx->delay_work); |
| 863 | set_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| 864 | } |
| 865 | EXPORT_SYMBOL(blk_mq_stop_hw_queue); |
| 866 | |
| 867 | void blk_mq_stop_hw_queues(struct request_queue *q) |
| 868 | { |
| 869 | struct blk_mq_hw_ctx *hctx; |
| 870 | int i; |
| 871 | |
| 872 | queue_for_each_hw_ctx(q, hctx, i) |
| 873 | blk_mq_stop_hw_queue(hctx); |
| 874 | } |
| 875 | EXPORT_SYMBOL(blk_mq_stop_hw_queues); |
| 876 | |
| 877 | void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) |
| 878 | { |
| 879 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| 880 | |
| 881 | blk_mq_run_hw_queue(hctx, false); |
| 882 | } |
| 883 | EXPORT_SYMBOL(blk_mq_start_hw_queue); |
| 884 | |
| 885 | void blk_mq_start_hw_queues(struct request_queue *q) |
| 886 | { |
| 887 | struct blk_mq_hw_ctx *hctx; |
| 888 | int i; |
| 889 | |
| 890 | queue_for_each_hw_ctx(q, hctx, i) |
| 891 | blk_mq_start_hw_queue(hctx); |
| 892 | } |
| 893 | EXPORT_SYMBOL(blk_mq_start_hw_queues); |
| 894 | |
| 895 | |
| 896 | void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) |
| 897 | { |
| 898 | struct blk_mq_hw_ctx *hctx; |
| 899 | int i; |
| 900 | |
| 901 | queue_for_each_hw_ctx(q, hctx, i) { |
| 902 | if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state)) |
| 903 | continue; |
| 904 | |
| 905 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| 906 | blk_mq_run_hw_queue(hctx, async); |
| 907 | } |
| 908 | } |
| 909 | EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); |
| 910 | |
| 911 | static void blk_mq_run_work_fn(struct work_struct *work) |
| 912 | { |
| 913 | struct blk_mq_hw_ctx *hctx; |
| 914 | |
| 915 | hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); |
| 916 | |
| 917 | __blk_mq_run_hw_queue(hctx); |
| 918 | } |
| 919 | |
| 920 | static void blk_mq_delay_work_fn(struct work_struct *work) |
| 921 | { |
| 922 | struct blk_mq_hw_ctx *hctx; |
| 923 | |
| 924 | hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work); |
| 925 | |
| 926 | if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state)) |
| 927 | __blk_mq_run_hw_queue(hctx); |
| 928 | } |
| 929 | |
| 930 | void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) |
| 931 | { |
| 932 | if (unlikely(!blk_mq_hw_queue_mapped(hctx))) |
| 933 | return; |
| 934 | |
| 935 | kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| 936 | &hctx->delay_work, msecs_to_jiffies(msecs)); |
| 937 | } |
| 938 | EXPORT_SYMBOL(blk_mq_delay_queue); |
| 939 | |
| 940 | static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, |
| 941 | struct request *rq, bool at_head) |
| 942 | { |
| 943 | struct blk_mq_ctx *ctx = rq->mq_ctx; |
| 944 | |
| 945 | trace_block_rq_insert(hctx->queue, rq); |
| 946 | |
| 947 | if (at_head) |
| 948 | list_add(&rq->queuelist, &ctx->rq_list); |
| 949 | else |
| 950 | list_add_tail(&rq->queuelist, &ctx->rq_list); |
| 951 | |
| 952 | blk_mq_hctx_mark_pending(hctx, ctx); |
| 953 | } |
| 954 | |
| 955 | void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue, |
| 956 | bool async) |
| 957 | { |
| 958 | struct request_queue *q = rq->q; |
| 959 | struct blk_mq_hw_ctx *hctx; |
| 960 | struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx; |
| 961 | |
| 962 | current_ctx = blk_mq_get_ctx(q); |
| 963 | if (!cpu_online(ctx->cpu)) |
| 964 | rq->mq_ctx = ctx = current_ctx; |
| 965 | |
| 966 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 967 | |
| 968 | spin_lock(&ctx->lock); |
| 969 | __blk_mq_insert_request(hctx, rq, at_head); |
| 970 | spin_unlock(&ctx->lock); |
| 971 | |
| 972 | if (run_queue) |
| 973 | blk_mq_run_hw_queue(hctx, async); |
| 974 | |
| 975 | blk_mq_put_ctx(current_ctx); |
| 976 | } |
| 977 | |
| 978 | static void blk_mq_insert_requests(struct request_queue *q, |
| 979 | struct blk_mq_ctx *ctx, |
| 980 | struct list_head *list, |
| 981 | int depth, |
| 982 | bool from_schedule) |
| 983 | |
| 984 | { |
| 985 | struct blk_mq_hw_ctx *hctx; |
| 986 | struct blk_mq_ctx *current_ctx; |
| 987 | |
| 988 | trace_block_unplug(q, depth, !from_schedule); |
| 989 | |
| 990 | current_ctx = blk_mq_get_ctx(q); |
| 991 | |
| 992 | if (!cpu_online(ctx->cpu)) |
| 993 | ctx = current_ctx; |
| 994 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 995 | |
| 996 | /* |
| 997 | * preemption doesn't flush plug list, so it's possible ctx->cpu is |
| 998 | * offline now |
| 999 | */ |
| 1000 | spin_lock(&ctx->lock); |
| 1001 | while (!list_empty(list)) { |
| 1002 | struct request *rq; |
| 1003 | |
| 1004 | rq = list_first_entry(list, struct request, queuelist); |
| 1005 | list_del_init(&rq->queuelist); |
| 1006 | rq->mq_ctx = ctx; |
| 1007 | __blk_mq_insert_request(hctx, rq, false); |
| 1008 | } |
| 1009 | spin_unlock(&ctx->lock); |
| 1010 | |
| 1011 | blk_mq_run_hw_queue(hctx, from_schedule); |
| 1012 | blk_mq_put_ctx(current_ctx); |
| 1013 | } |
| 1014 | |
| 1015 | static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b) |
| 1016 | { |
| 1017 | struct request *rqa = container_of(a, struct request, queuelist); |
| 1018 | struct request *rqb = container_of(b, struct request, queuelist); |
| 1019 | |
| 1020 | return !(rqa->mq_ctx < rqb->mq_ctx || |
| 1021 | (rqa->mq_ctx == rqb->mq_ctx && |
| 1022 | blk_rq_pos(rqa) < blk_rq_pos(rqb))); |
| 1023 | } |
| 1024 | |
| 1025 | void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
| 1026 | { |
| 1027 | struct blk_mq_ctx *this_ctx; |
| 1028 | struct request_queue *this_q; |
| 1029 | struct request *rq; |
| 1030 | LIST_HEAD(list); |
| 1031 | LIST_HEAD(ctx_list); |
| 1032 | unsigned int depth; |
| 1033 | |
| 1034 | list_splice_init(&plug->mq_list, &list); |
| 1035 | |
| 1036 | list_sort(NULL, &list, plug_ctx_cmp); |
| 1037 | |
| 1038 | this_q = NULL; |
| 1039 | this_ctx = NULL; |
| 1040 | depth = 0; |
| 1041 | |
| 1042 | while (!list_empty(&list)) { |
| 1043 | rq = list_entry_rq(list.next); |
| 1044 | list_del_init(&rq->queuelist); |
| 1045 | BUG_ON(!rq->q); |
| 1046 | if (rq->mq_ctx != this_ctx) { |
| 1047 | if (this_ctx) { |
| 1048 | blk_mq_insert_requests(this_q, this_ctx, |
| 1049 | &ctx_list, depth, |
| 1050 | from_schedule); |
| 1051 | } |
| 1052 | |
| 1053 | this_ctx = rq->mq_ctx; |
| 1054 | this_q = rq->q; |
| 1055 | depth = 0; |
| 1056 | } |
| 1057 | |
| 1058 | depth++; |
| 1059 | list_add_tail(&rq->queuelist, &ctx_list); |
| 1060 | } |
| 1061 | |
| 1062 | /* |
| 1063 | * If 'this_ctx' is set, we know we have entries to complete |
| 1064 | * on 'ctx_list'. Do those. |
| 1065 | */ |
| 1066 | if (this_ctx) { |
| 1067 | blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth, |
| 1068 | from_schedule); |
| 1069 | } |
| 1070 | } |
| 1071 | |
| 1072 | static void blk_mq_bio_to_request(struct request *rq, struct bio *bio) |
| 1073 | { |
| 1074 | init_request_from_bio(rq, bio); |
| 1075 | |
| 1076 | if (blk_do_io_stat(rq)) |
| 1077 | blk_account_io_start(rq, 1); |
| 1078 | } |
| 1079 | |
| 1080 | static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx) |
| 1081 | { |
| 1082 | return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) && |
| 1083 | !blk_queue_nomerges(hctx->queue); |
| 1084 | } |
| 1085 | |
| 1086 | static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx, |
| 1087 | struct blk_mq_ctx *ctx, |
| 1088 | struct request *rq, struct bio *bio) |
| 1089 | { |
| 1090 | if (!hctx_allow_merges(hctx)) { |
| 1091 | blk_mq_bio_to_request(rq, bio); |
| 1092 | spin_lock(&ctx->lock); |
| 1093 | insert_rq: |
| 1094 | __blk_mq_insert_request(hctx, rq, false); |
| 1095 | spin_unlock(&ctx->lock); |
| 1096 | return false; |
| 1097 | } else { |
| 1098 | struct request_queue *q = hctx->queue; |
| 1099 | |
| 1100 | spin_lock(&ctx->lock); |
| 1101 | if (!blk_mq_attempt_merge(q, ctx, bio)) { |
| 1102 | blk_mq_bio_to_request(rq, bio); |
| 1103 | goto insert_rq; |
| 1104 | } |
| 1105 | |
| 1106 | spin_unlock(&ctx->lock); |
| 1107 | __blk_mq_free_request(hctx, ctx, rq); |
| 1108 | return true; |
| 1109 | } |
| 1110 | } |
| 1111 | |
| 1112 | struct blk_map_ctx { |
| 1113 | struct blk_mq_hw_ctx *hctx; |
| 1114 | struct blk_mq_ctx *ctx; |
| 1115 | }; |
| 1116 | |
| 1117 | static struct request *blk_mq_map_request(struct request_queue *q, |
| 1118 | struct bio *bio, |
| 1119 | struct blk_map_ctx *data) |
| 1120 | { |
| 1121 | struct blk_mq_hw_ctx *hctx; |
| 1122 | struct blk_mq_ctx *ctx; |
| 1123 | struct request *rq; |
| 1124 | int rw = bio_data_dir(bio); |
| 1125 | struct blk_mq_alloc_data alloc_data; |
| 1126 | |
| 1127 | if (unlikely(blk_mq_queue_enter(q))) { |
| 1128 | bio_endio(bio, -EIO); |
| 1129 | return NULL; |
| 1130 | } |
| 1131 | |
| 1132 | ctx = blk_mq_get_ctx(q); |
| 1133 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 1134 | |
| 1135 | if (rw_is_sync(bio->bi_rw)) |
| 1136 | rw |= REQ_SYNC; |
| 1137 | |
| 1138 | trace_block_getrq(q, bio, rw); |
| 1139 | blk_mq_set_alloc_data(&alloc_data, q, GFP_ATOMIC, false, ctx, |
| 1140 | hctx); |
| 1141 | rq = __blk_mq_alloc_request(&alloc_data, rw); |
| 1142 | if (unlikely(!rq)) { |
| 1143 | __blk_mq_run_hw_queue(hctx); |
| 1144 | blk_mq_put_ctx(ctx); |
| 1145 | trace_block_sleeprq(q, bio, rw); |
| 1146 | |
| 1147 | ctx = blk_mq_get_ctx(q); |
| 1148 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 1149 | blk_mq_set_alloc_data(&alloc_data, q, |
| 1150 | __GFP_WAIT|GFP_ATOMIC, false, ctx, hctx); |
| 1151 | rq = __blk_mq_alloc_request(&alloc_data, rw); |
| 1152 | ctx = alloc_data.ctx; |
| 1153 | hctx = alloc_data.hctx; |
| 1154 | } |
| 1155 | |
| 1156 | hctx->queued++; |
| 1157 | data->hctx = hctx; |
| 1158 | data->ctx = ctx; |
| 1159 | return rq; |
| 1160 | } |
| 1161 | |
| 1162 | /* |
| 1163 | * Multiple hardware queue variant. This will not use per-process plugs, |
| 1164 | * but will attempt to bypass the hctx queueing if we can go straight to |
| 1165 | * hardware for SYNC IO. |
| 1166 | */ |
| 1167 | static void blk_mq_make_request(struct request_queue *q, struct bio *bio) |
| 1168 | { |
| 1169 | const int is_sync = rw_is_sync(bio->bi_rw); |
| 1170 | const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); |
| 1171 | struct blk_map_ctx data; |
| 1172 | struct request *rq; |
| 1173 | |
| 1174 | blk_queue_bounce(q, &bio); |
| 1175 | |
| 1176 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
| 1177 | bio_endio(bio, -EIO); |
| 1178 | return; |
| 1179 | } |
| 1180 | |
| 1181 | rq = blk_mq_map_request(q, bio, &data); |
| 1182 | if (unlikely(!rq)) |
| 1183 | return; |
| 1184 | |
| 1185 | if (unlikely(is_flush_fua)) { |
| 1186 | blk_mq_bio_to_request(rq, bio); |
| 1187 | blk_insert_flush(rq); |
| 1188 | goto run_queue; |
| 1189 | } |
| 1190 | |
| 1191 | /* |
| 1192 | * If the driver supports defer issued based on 'last', then |
| 1193 | * queue it up like normal since we can potentially save some |
| 1194 | * CPU this way. |
| 1195 | */ |
| 1196 | if (is_sync && !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) { |
| 1197 | struct blk_mq_queue_data bd = { |
| 1198 | .rq = rq, |
| 1199 | .list = NULL, |
| 1200 | .last = 1 |
| 1201 | }; |
| 1202 | int ret; |
| 1203 | |
| 1204 | blk_mq_bio_to_request(rq, bio); |
| 1205 | |
| 1206 | /* |
| 1207 | * For OK queue, we are done. For error, kill it. Any other |
| 1208 | * error (busy), just add it to our list as we previously |
| 1209 | * would have done |
| 1210 | */ |
| 1211 | ret = q->mq_ops->queue_rq(data.hctx, &bd); |
| 1212 | if (ret == BLK_MQ_RQ_QUEUE_OK) |
| 1213 | goto done; |
| 1214 | else { |
| 1215 | __blk_mq_requeue_request(rq); |
| 1216 | |
| 1217 | if (ret == BLK_MQ_RQ_QUEUE_ERROR) { |
| 1218 | rq->errors = -EIO; |
| 1219 | blk_mq_end_request(rq, rq->errors); |
| 1220 | goto done; |
| 1221 | } |
| 1222 | } |
| 1223 | } |
| 1224 | |
| 1225 | if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { |
| 1226 | /* |
| 1227 | * For a SYNC request, send it to the hardware immediately. For |
| 1228 | * an ASYNC request, just ensure that we run it later on. The |
| 1229 | * latter allows for merging opportunities and more efficient |
| 1230 | * dispatching. |
| 1231 | */ |
| 1232 | run_queue: |
| 1233 | blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); |
| 1234 | } |
| 1235 | done: |
| 1236 | blk_mq_put_ctx(data.ctx); |
| 1237 | } |
| 1238 | |
| 1239 | /* |
| 1240 | * Single hardware queue variant. This will attempt to use any per-process |
| 1241 | * plug for merging and IO deferral. |
| 1242 | */ |
| 1243 | static void blk_sq_make_request(struct request_queue *q, struct bio *bio) |
| 1244 | { |
| 1245 | const int is_sync = rw_is_sync(bio->bi_rw); |
| 1246 | const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); |
| 1247 | unsigned int use_plug, request_count = 0; |
| 1248 | struct blk_map_ctx data; |
| 1249 | struct request *rq; |
| 1250 | |
| 1251 | /* |
| 1252 | * If we have multiple hardware queues, just go directly to |
| 1253 | * one of those for sync IO. |
| 1254 | */ |
| 1255 | use_plug = !is_flush_fua && !is_sync; |
| 1256 | |
| 1257 | blk_queue_bounce(q, &bio); |
| 1258 | |
| 1259 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
| 1260 | bio_endio(bio, -EIO); |
| 1261 | return; |
| 1262 | } |
| 1263 | |
| 1264 | if (use_plug && !blk_queue_nomerges(q) && |
| 1265 | blk_attempt_plug_merge(q, bio, &request_count)) |
| 1266 | return; |
| 1267 | |
| 1268 | rq = blk_mq_map_request(q, bio, &data); |
| 1269 | if (unlikely(!rq)) |
| 1270 | return; |
| 1271 | |
| 1272 | if (unlikely(is_flush_fua)) { |
| 1273 | blk_mq_bio_to_request(rq, bio); |
| 1274 | blk_insert_flush(rq); |
| 1275 | goto run_queue; |
| 1276 | } |
| 1277 | |
| 1278 | /* |
| 1279 | * A task plug currently exists. Since this is completely lockless, |
| 1280 | * utilize that to temporarily store requests until the task is |
| 1281 | * either done or scheduled away. |
| 1282 | */ |
| 1283 | if (use_plug) { |
| 1284 | struct blk_plug *plug = current->plug; |
| 1285 | |
| 1286 | if (plug) { |
| 1287 | blk_mq_bio_to_request(rq, bio); |
| 1288 | if (list_empty(&plug->mq_list)) |
| 1289 | trace_block_plug(q); |
| 1290 | else if (request_count >= BLK_MAX_REQUEST_COUNT) { |
| 1291 | blk_flush_plug_list(plug, false); |
| 1292 | trace_block_plug(q); |
| 1293 | } |
| 1294 | list_add_tail(&rq->queuelist, &plug->mq_list); |
| 1295 | blk_mq_put_ctx(data.ctx); |
| 1296 | return; |
| 1297 | } |
| 1298 | } |
| 1299 | |
| 1300 | if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { |
| 1301 | /* |
| 1302 | * For a SYNC request, send it to the hardware immediately. For |
| 1303 | * an ASYNC request, just ensure that we run it later on. The |
| 1304 | * latter allows for merging opportunities and more efficient |
| 1305 | * dispatching. |
| 1306 | */ |
| 1307 | run_queue: |
| 1308 | blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); |
| 1309 | } |
| 1310 | |
| 1311 | blk_mq_put_ctx(data.ctx); |
| 1312 | } |
| 1313 | |
| 1314 | /* |
| 1315 | * Default mapping to a software queue, since we use one per CPU. |
| 1316 | */ |
| 1317 | struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, const int cpu) |
| 1318 | { |
| 1319 | return q->queue_hw_ctx[q->mq_map[cpu]]; |
| 1320 | } |
| 1321 | EXPORT_SYMBOL(blk_mq_map_queue); |
| 1322 | |
| 1323 | static void blk_mq_free_rq_map(struct blk_mq_tag_set *set, |
| 1324 | struct blk_mq_tags *tags, unsigned int hctx_idx) |
| 1325 | { |
| 1326 | struct page *page; |
| 1327 | |
| 1328 | if (tags->rqs && set->ops->exit_request) { |
| 1329 | int i; |
| 1330 | |
| 1331 | for (i = 0; i < tags->nr_tags; i++) { |
| 1332 | if (!tags->rqs[i]) |
| 1333 | continue; |
| 1334 | set->ops->exit_request(set->driver_data, tags->rqs[i], |
| 1335 | hctx_idx, i); |
| 1336 | tags->rqs[i] = NULL; |
| 1337 | } |
| 1338 | } |
| 1339 | |
| 1340 | while (!list_empty(&tags->page_list)) { |
| 1341 | page = list_first_entry(&tags->page_list, struct page, lru); |
| 1342 | list_del_init(&page->lru); |
| 1343 | __free_pages(page, page->private); |
| 1344 | } |
| 1345 | |
| 1346 | kfree(tags->rqs); |
| 1347 | |
| 1348 | blk_mq_free_tags(tags); |
| 1349 | } |
| 1350 | |
| 1351 | static size_t order_to_size(unsigned int order) |
| 1352 | { |
| 1353 | return (size_t)PAGE_SIZE << order; |
| 1354 | } |
| 1355 | |
| 1356 | static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, |
| 1357 | unsigned int hctx_idx) |
| 1358 | { |
| 1359 | struct blk_mq_tags *tags; |
| 1360 | unsigned int i, j, entries_per_page, max_order = 4; |
| 1361 | size_t rq_size, left; |
| 1362 | |
| 1363 | tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags, |
| 1364 | set->numa_node); |
| 1365 | if (!tags) |
| 1366 | return NULL; |
| 1367 | |
| 1368 | INIT_LIST_HEAD(&tags->page_list); |
| 1369 | |
| 1370 | tags->rqs = kzalloc_node(set->queue_depth * sizeof(struct request *), |
| 1371 | GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY, |
| 1372 | set->numa_node); |
| 1373 | if (!tags->rqs) { |
| 1374 | blk_mq_free_tags(tags); |
| 1375 | return NULL; |
| 1376 | } |
| 1377 | |
| 1378 | /* |
| 1379 | * rq_size is the size of the request plus driver payload, rounded |
| 1380 | * to the cacheline size |
| 1381 | */ |
| 1382 | rq_size = round_up(sizeof(struct request) + set->cmd_size, |
| 1383 | cache_line_size()); |
| 1384 | left = rq_size * set->queue_depth; |
| 1385 | |
| 1386 | for (i = 0; i < set->queue_depth; ) { |
| 1387 | int this_order = max_order; |
| 1388 | struct page *page; |
| 1389 | int to_do; |
| 1390 | void *p; |
| 1391 | |
| 1392 | while (left < order_to_size(this_order - 1) && this_order) |
| 1393 | this_order--; |
| 1394 | |
| 1395 | do { |
| 1396 | page = alloc_pages_node(set->numa_node, |
| 1397 | GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY, |
| 1398 | this_order); |
| 1399 | if (page) |
| 1400 | break; |
| 1401 | if (!this_order--) |
| 1402 | break; |
| 1403 | if (order_to_size(this_order) < rq_size) |
| 1404 | break; |
| 1405 | } while (1); |
| 1406 | |
| 1407 | if (!page) |
| 1408 | goto fail; |
| 1409 | |
| 1410 | page->private = this_order; |
| 1411 | list_add_tail(&page->lru, &tags->page_list); |
| 1412 | |
| 1413 | p = page_address(page); |
| 1414 | entries_per_page = order_to_size(this_order) / rq_size; |
| 1415 | to_do = min(entries_per_page, set->queue_depth - i); |
| 1416 | left -= to_do * rq_size; |
| 1417 | for (j = 0; j < to_do; j++) { |
| 1418 | tags->rqs[i] = p; |
| 1419 | tags->rqs[i]->atomic_flags = 0; |
| 1420 | tags->rqs[i]->cmd_flags = 0; |
| 1421 | if (set->ops->init_request) { |
| 1422 | if (set->ops->init_request(set->driver_data, |
| 1423 | tags->rqs[i], hctx_idx, i, |
| 1424 | set->numa_node)) { |
| 1425 | tags->rqs[i] = NULL; |
| 1426 | goto fail; |
| 1427 | } |
| 1428 | } |
| 1429 | |
| 1430 | p += rq_size; |
| 1431 | i++; |
| 1432 | } |
| 1433 | } |
| 1434 | |
| 1435 | return tags; |
| 1436 | |
| 1437 | fail: |
| 1438 | blk_mq_free_rq_map(set, tags, hctx_idx); |
| 1439 | return NULL; |
| 1440 | } |
| 1441 | |
| 1442 | static void blk_mq_free_bitmap(struct blk_mq_ctxmap *bitmap) |
| 1443 | { |
| 1444 | kfree(bitmap->map); |
| 1445 | } |
| 1446 | |
| 1447 | static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap *bitmap, int node) |
| 1448 | { |
| 1449 | unsigned int bpw = 8, total, num_maps, i; |
| 1450 | |
| 1451 | bitmap->bits_per_word = bpw; |
| 1452 | |
| 1453 | num_maps = ALIGN(nr_cpu_ids, bpw) / bpw; |
| 1454 | bitmap->map = kzalloc_node(num_maps * sizeof(struct blk_align_bitmap), |
| 1455 | GFP_KERNEL, node); |
| 1456 | if (!bitmap->map) |
| 1457 | return -ENOMEM; |
| 1458 | |
| 1459 | bitmap->map_size = num_maps; |
| 1460 | |
| 1461 | total = nr_cpu_ids; |
| 1462 | for (i = 0; i < num_maps; i++) { |
| 1463 | bitmap->map[i].depth = min(total, bitmap->bits_per_word); |
| 1464 | total -= bitmap->map[i].depth; |
| 1465 | } |
| 1466 | |
| 1467 | return 0; |
| 1468 | } |
| 1469 | |
| 1470 | static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu) |
| 1471 | { |
| 1472 | struct request_queue *q = hctx->queue; |
| 1473 | struct blk_mq_ctx *ctx; |
| 1474 | LIST_HEAD(tmp); |
| 1475 | |
| 1476 | /* |
| 1477 | * Move ctx entries to new CPU, if this one is going away. |
| 1478 | */ |
| 1479 | ctx = __blk_mq_get_ctx(q, cpu); |
| 1480 | |
| 1481 | spin_lock(&ctx->lock); |
| 1482 | if (!list_empty(&ctx->rq_list)) { |
| 1483 | list_splice_init(&ctx->rq_list, &tmp); |
| 1484 | blk_mq_hctx_clear_pending(hctx, ctx); |
| 1485 | } |
| 1486 | spin_unlock(&ctx->lock); |
| 1487 | |
| 1488 | if (list_empty(&tmp)) |
| 1489 | return NOTIFY_OK; |
| 1490 | |
| 1491 | ctx = blk_mq_get_ctx(q); |
| 1492 | spin_lock(&ctx->lock); |
| 1493 | |
| 1494 | while (!list_empty(&tmp)) { |
| 1495 | struct request *rq; |
| 1496 | |
| 1497 | rq = list_first_entry(&tmp, struct request, queuelist); |
| 1498 | rq->mq_ctx = ctx; |
| 1499 | list_move_tail(&rq->queuelist, &ctx->rq_list); |
| 1500 | } |
| 1501 | |
| 1502 | hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| 1503 | blk_mq_hctx_mark_pending(hctx, ctx); |
| 1504 | |
| 1505 | spin_unlock(&ctx->lock); |
| 1506 | |
| 1507 | blk_mq_run_hw_queue(hctx, true); |
| 1508 | blk_mq_put_ctx(ctx); |
| 1509 | return NOTIFY_OK; |
| 1510 | } |
| 1511 | |
| 1512 | static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx *hctx, int cpu) |
| 1513 | { |
| 1514 | struct request_queue *q = hctx->queue; |
| 1515 | struct blk_mq_tag_set *set = q->tag_set; |
| 1516 | |
| 1517 | if (set->tags[hctx->queue_num]) |
| 1518 | return NOTIFY_OK; |
| 1519 | |
| 1520 | set->tags[hctx->queue_num] = blk_mq_init_rq_map(set, hctx->queue_num); |
| 1521 | if (!set->tags[hctx->queue_num]) |
| 1522 | return NOTIFY_STOP; |
| 1523 | |
| 1524 | hctx->tags = set->tags[hctx->queue_num]; |
| 1525 | return NOTIFY_OK; |
| 1526 | } |
| 1527 | |
| 1528 | static int blk_mq_hctx_notify(void *data, unsigned long action, |
| 1529 | unsigned int cpu) |
| 1530 | { |
| 1531 | struct blk_mq_hw_ctx *hctx = data; |
| 1532 | |
| 1533 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) |
| 1534 | return blk_mq_hctx_cpu_offline(hctx, cpu); |
| 1535 | else if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) |
| 1536 | return blk_mq_hctx_cpu_online(hctx, cpu); |
| 1537 | |
| 1538 | return NOTIFY_OK; |
| 1539 | } |
| 1540 | |
| 1541 | static void blk_mq_exit_hctx(struct request_queue *q, |
| 1542 | struct blk_mq_tag_set *set, |
| 1543 | struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) |
| 1544 | { |
| 1545 | unsigned flush_start_tag = set->queue_depth; |
| 1546 | |
| 1547 | blk_mq_tag_idle(hctx); |
| 1548 | |
| 1549 | if (set->ops->exit_request) |
| 1550 | set->ops->exit_request(set->driver_data, |
| 1551 | hctx->fq->flush_rq, hctx_idx, |
| 1552 | flush_start_tag + hctx_idx); |
| 1553 | |
| 1554 | if (set->ops->exit_hctx) |
| 1555 | set->ops->exit_hctx(hctx, hctx_idx); |
| 1556 | |
| 1557 | blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); |
| 1558 | blk_free_flush_queue(hctx->fq); |
| 1559 | kfree(hctx->ctxs); |
| 1560 | blk_mq_free_bitmap(&hctx->ctx_map); |
| 1561 | } |
| 1562 | |
| 1563 | static void blk_mq_exit_hw_queues(struct request_queue *q, |
| 1564 | struct blk_mq_tag_set *set, int nr_queue) |
| 1565 | { |
| 1566 | struct blk_mq_hw_ctx *hctx; |
| 1567 | unsigned int i; |
| 1568 | |
| 1569 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1570 | if (i == nr_queue) |
| 1571 | break; |
| 1572 | blk_mq_exit_hctx(q, set, hctx, i); |
| 1573 | } |
| 1574 | } |
| 1575 | |
| 1576 | static void blk_mq_free_hw_queues(struct request_queue *q, |
| 1577 | struct blk_mq_tag_set *set) |
| 1578 | { |
| 1579 | struct blk_mq_hw_ctx *hctx; |
| 1580 | unsigned int i; |
| 1581 | |
| 1582 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1583 | free_cpumask_var(hctx->cpumask); |
| 1584 | kfree(hctx); |
| 1585 | } |
| 1586 | } |
| 1587 | |
| 1588 | static int blk_mq_init_hctx(struct request_queue *q, |
| 1589 | struct blk_mq_tag_set *set, |
| 1590 | struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) |
| 1591 | { |
| 1592 | int node; |
| 1593 | unsigned flush_start_tag = set->queue_depth; |
| 1594 | |
| 1595 | node = hctx->numa_node; |
| 1596 | if (node == NUMA_NO_NODE) |
| 1597 | node = hctx->numa_node = set->numa_node; |
| 1598 | |
| 1599 | INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); |
| 1600 | INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn); |
| 1601 | spin_lock_init(&hctx->lock); |
| 1602 | INIT_LIST_HEAD(&hctx->dispatch); |
| 1603 | hctx->queue = q; |
| 1604 | hctx->queue_num = hctx_idx; |
| 1605 | hctx->flags = set->flags; |
| 1606 | hctx->cmd_size = set->cmd_size; |
| 1607 | |
| 1608 | blk_mq_init_cpu_notifier(&hctx->cpu_notifier, |
| 1609 | blk_mq_hctx_notify, hctx); |
| 1610 | blk_mq_register_cpu_notifier(&hctx->cpu_notifier); |
| 1611 | |
| 1612 | hctx->tags = set->tags[hctx_idx]; |
| 1613 | |
| 1614 | /* |
| 1615 | * Allocate space for all possible cpus to avoid allocation at |
| 1616 | * runtime |
| 1617 | */ |
| 1618 | hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *), |
| 1619 | GFP_KERNEL, node); |
| 1620 | if (!hctx->ctxs) |
| 1621 | goto unregister_cpu_notifier; |
| 1622 | |
| 1623 | if (blk_mq_alloc_bitmap(&hctx->ctx_map, node)) |
| 1624 | goto free_ctxs; |
| 1625 | |
| 1626 | hctx->nr_ctx = 0; |
| 1627 | |
| 1628 | if (set->ops->init_hctx && |
| 1629 | set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) |
| 1630 | goto free_bitmap; |
| 1631 | |
| 1632 | hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size); |
| 1633 | if (!hctx->fq) |
| 1634 | goto exit_hctx; |
| 1635 | |
| 1636 | if (set->ops->init_request && |
| 1637 | set->ops->init_request(set->driver_data, |
| 1638 | hctx->fq->flush_rq, hctx_idx, |
| 1639 | flush_start_tag + hctx_idx, node)) |
| 1640 | goto free_fq; |
| 1641 | |
| 1642 | return 0; |
| 1643 | |
| 1644 | free_fq: |
| 1645 | kfree(hctx->fq); |
| 1646 | exit_hctx: |
| 1647 | if (set->ops->exit_hctx) |
| 1648 | set->ops->exit_hctx(hctx, hctx_idx); |
| 1649 | free_bitmap: |
| 1650 | blk_mq_free_bitmap(&hctx->ctx_map); |
| 1651 | free_ctxs: |
| 1652 | kfree(hctx->ctxs); |
| 1653 | unregister_cpu_notifier: |
| 1654 | blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); |
| 1655 | |
| 1656 | return -1; |
| 1657 | } |
| 1658 | |
| 1659 | static int blk_mq_init_hw_queues(struct request_queue *q, |
| 1660 | struct blk_mq_tag_set *set) |
| 1661 | { |
| 1662 | struct blk_mq_hw_ctx *hctx; |
| 1663 | unsigned int i; |
| 1664 | |
| 1665 | /* |
| 1666 | * Initialize hardware queues |
| 1667 | */ |
| 1668 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1669 | if (blk_mq_init_hctx(q, set, hctx, i)) |
| 1670 | break; |
| 1671 | } |
| 1672 | |
| 1673 | if (i == q->nr_hw_queues) |
| 1674 | return 0; |
| 1675 | |
| 1676 | /* |
| 1677 | * Init failed |
| 1678 | */ |
| 1679 | blk_mq_exit_hw_queues(q, set, i); |
| 1680 | |
| 1681 | return 1; |
| 1682 | } |
| 1683 | |
| 1684 | static void blk_mq_init_cpu_queues(struct request_queue *q, |
| 1685 | unsigned int nr_hw_queues) |
| 1686 | { |
| 1687 | unsigned int i; |
| 1688 | |
| 1689 | for_each_possible_cpu(i) { |
| 1690 | struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); |
| 1691 | struct blk_mq_hw_ctx *hctx; |
| 1692 | |
| 1693 | memset(__ctx, 0, sizeof(*__ctx)); |
| 1694 | __ctx->cpu = i; |
| 1695 | spin_lock_init(&__ctx->lock); |
| 1696 | INIT_LIST_HEAD(&__ctx->rq_list); |
| 1697 | __ctx->queue = q; |
| 1698 | |
| 1699 | /* If the cpu isn't online, the cpu is mapped to first hctx */ |
| 1700 | if (!cpu_online(i)) |
| 1701 | continue; |
| 1702 | |
| 1703 | hctx = q->mq_ops->map_queue(q, i); |
| 1704 | cpumask_set_cpu(i, hctx->cpumask); |
| 1705 | hctx->nr_ctx++; |
| 1706 | |
| 1707 | /* |
| 1708 | * Set local node, IFF we have more than one hw queue. If |
| 1709 | * not, we remain on the home node of the device |
| 1710 | */ |
| 1711 | if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) |
| 1712 | hctx->numa_node = cpu_to_node(i); |
| 1713 | } |
| 1714 | } |
| 1715 | |
| 1716 | static void blk_mq_map_swqueue(struct request_queue *q) |
| 1717 | { |
| 1718 | unsigned int i; |
| 1719 | struct blk_mq_hw_ctx *hctx; |
| 1720 | struct blk_mq_ctx *ctx; |
| 1721 | |
| 1722 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1723 | cpumask_clear(hctx->cpumask); |
| 1724 | hctx->nr_ctx = 0; |
| 1725 | } |
| 1726 | |
| 1727 | /* |
| 1728 | * Map software to hardware queues |
| 1729 | */ |
| 1730 | queue_for_each_ctx(q, ctx, i) { |
| 1731 | /* If the cpu isn't online, the cpu is mapped to first hctx */ |
| 1732 | if (!cpu_online(i)) |
| 1733 | continue; |
| 1734 | |
| 1735 | hctx = q->mq_ops->map_queue(q, i); |
| 1736 | cpumask_set_cpu(i, hctx->cpumask); |
| 1737 | ctx->index_hw = hctx->nr_ctx; |
| 1738 | hctx->ctxs[hctx->nr_ctx++] = ctx; |
| 1739 | } |
| 1740 | |
| 1741 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1742 | /* |
| 1743 | * If no software queues are mapped to this hardware queue, |
| 1744 | * disable it and free the request entries. |
| 1745 | */ |
| 1746 | if (!hctx->nr_ctx) { |
| 1747 | struct blk_mq_tag_set *set = q->tag_set; |
| 1748 | |
| 1749 | if (set->tags[i]) { |
| 1750 | blk_mq_free_rq_map(set, set->tags[i], i); |
| 1751 | set->tags[i] = NULL; |
| 1752 | hctx->tags = NULL; |
| 1753 | } |
| 1754 | continue; |
| 1755 | } |
| 1756 | |
| 1757 | /* |
| 1758 | * Initialize batch roundrobin counts |
| 1759 | */ |
| 1760 | hctx->next_cpu = cpumask_first(hctx->cpumask); |
| 1761 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| 1762 | } |
| 1763 | } |
| 1764 | |
| 1765 | static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set) |
| 1766 | { |
| 1767 | struct blk_mq_hw_ctx *hctx; |
| 1768 | struct request_queue *q; |
| 1769 | bool shared; |
| 1770 | int i; |
| 1771 | |
| 1772 | if (set->tag_list.next == set->tag_list.prev) |
| 1773 | shared = false; |
| 1774 | else |
| 1775 | shared = true; |
| 1776 | |
| 1777 | list_for_each_entry(q, &set->tag_list, tag_set_list) { |
| 1778 | blk_mq_freeze_queue(q); |
| 1779 | |
| 1780 | queue_for_each_hw_ctx(q, hctx, i) { |
| 1781 | if (shared) |
| 1782 | hctx->flags |= BLK_MQ_F_TAG_SHARED; |
| 1783 | else |
| 1784 | hctx->flags &= ~BLK_MQ_F_TAG_SHARED; |
| 1785 | } |
| 1786 | blk_mq_unfreeze_queue(q); |
| 1787 | } |
| 1788 | } |
| 1789 | |
| 1790 | static void blk_mq_del_queue_tag_set(struct request_queue *q) |
| 1791 | { |
| 1792 | struct blk_mq_tag_set *set = q->tag_set; |
| 1793 | |
| 1794 | mutex_lock(&set->tag_list_lock); |
| 1795 | list_del_init(&q->tag_set_list); |
| 1796 | blk_mq_update_tag_set_depth(set); |
| 1797 | mutex_unlock(&set->tag_list_lock); |
| 1798 | } |
| 1799 | |
| 1800 | static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, |
| 1801 | struct request_queue *q) |
| 1802 | { |
| 1803 | q->tag_set = set; |
| 1804 | |
| 1805 | mutex_lock(&set->tag_list_lock); |
| 1806 | list_add_tail(&q->tag_set_list, &set->tag_list); |
| 1807 | blk_mq_update_tag_set_depth(set); |
| 1808 | mutex_unlock(&set->tag_list_lock); |
| 1809 | } |
| 1810 | |
| 1811 | struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) |
| 1812 | { |
| 1813 | struct blk_mq_hw_ctx **hctxs; |
| 1814 | struct blk_mq_ctx __percpu *ctx; |
| 1815 | struct request_queue *q; |
| 1816 | unsigned int *map; |
| 1817 | int i; |
| 1818 | |
| 1819 | ctx = alloc_percpu(struct blk_mq_ctx); |
| 1820 | if (!ctx) |
| 1821 | return ERR_PTR(-ENOMEM); |
| 1822 | |
| 1823 | hctxs = kmalloc_node(set->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL, |
| 1824 | set->numa_node); |
| 1825 | |
| 1826 | if (!hctxs) |
| 1827 | goto err_percpu; |
| 1828 | |
| 1829 | map = blk_mq_make_queue_map(set); |
| 1830 | if (!map) |
| 1831 | goto err_map; |
| 1832 | |
| 1833 | for (i = 0; i < set->nr_hw_queues; i++) { |
| 1834 | int node = blk_mq_hw_queue_to_node(map, i); |
| 1835 | |
| 1836 | hctxs[i] = kzalloc_node(sizeof(struct blk_mq_hw_ctx), |
| 1837 | GFP_KERNEL, node); |
| 1838 | if (!hctxs[i]) |
| 1839 | goto err_hctxs; |
| 1840 | |
| 1841 | if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL, |
| 1842 | node)) |
| 1843 | goto err_hctxs; |
| 1844 | |
| 1845 | atomic_set(&hctxs[i]->nr_active, 0); |
| 1846 | hctxs[i]->numa_node = node; |
| 1847 | hctxs[i]->queue_num = i; |
| 1848 | } |
| 1849 | |
| 1850 | q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node); |
| 1851 | if (!q) |
| 1852 | goto err_hctxs; |
| 1853 | |
| 1854 | /* |
| 1855 | * Init percpu_ref in atomic mode so that it's faster to shutdown. |
| 1856 | * See blk_register_queue() for details. |
| 1857 | */ |
| 1858 | if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release, |
| 1859 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) |
| 1860 | goto err_map; |
| 1861 | |
| 1862 | setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); |
| 1863 | blk_queue_rq_timeout(q, 30000); |
| 1864 | |
| 1865 | q->nr_queues = nr_cpu_ids; |
| 1866 | q->nr_hw_queues = set->nr_hw_queues; |
| 1867 | q->mq_map = map; |
| 1868 | |
| 1869 | q->queue_ctx = ctx; |
| 1870 | q->queue_hw_ctx = hctxs; |
| 1871 | |
| 1872 | q->mq_ops = set->ops; |
| 1873 | q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; |
| 1874 | |
| 1875 | if (!(set->flags & BLK_MQ_F_SG_MERGE)) |
| 1876 | q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE; |
| 1877 | |
| 1878 | q->sg_reserved_size = INT_MAX; |
| 1879 | |
| 1880 | INIT_WORK(&q->requeue_work, blk_mq_requeue_work); |
| 1881 | INIT_LIST_HEAD(&q->requeue_list); |
| 1882 | spin_lock_init(&q->requeue_lock); |
| 1883 | |
| 1884 | if (q->nr_hw_queues > 1) |
| 1885 | blk_queue_make_request(q, blk_mq_make_request); |
| 1886 | else |
| 1887 | blk_queue_make_request(q, blk_sq_make_request); |
| 1888 | |
| 1889 | if (set->timeout) |
| 1890 | blk_queue_rq_timeout(q, set->timeout); |
| 1891 | |
| 1892 | /* |
| 1893 | * Do this after blk_queue_make_request() overrides it... |
| 1894 | */ |
| 1895 | q->nr_requests = set->queue_depth; |
| 1896 | |
| 1897 | if (set->ops->complete) |
| 1898 | blk_queue_softirq_done(q, set->ops->complete); |
| 1899 | |
| 1900 | blk_mq_init_cpu_queues(q, set->nr_hw_queues); |
| 1901 | |
| 1902 | if (blk_mq_init_hw_queues(q, set)) |
| 1903 | goto err_hw; |
| 1904 | |
| 1905 | mutex_lock(&all_q_mutex); |
| 1906 | list_add_tail(&q->all_q_node, &all_q_list); |
| 1907 | mutex_unlock(&all_q_mutex); |
| 1908 | |
| 1909 | blk_mq_add_queue_tag_set(set, q); |
| 1910 | |
| 1911 | blk_mq_map_swqueue(q); |
| 1912 | |
| 1913 | return q; |
| 1914 | |
| 1915 | err_hw: |
| 1916 | blk_cleanup_queue(q); |
| 1917 | err_hctxs: |
| 1918 | kfree(map); |
| 1919 | for (i = 0; i < set->nr_hw_queues; i++) { |
| 1920 | if (!hctxs[i]) |
| 1921 | break; |
| 1922 | free_cpumask_var(hctxs[i]->cpumask); |
| 1923 | kfree(hctxs[i]); |
| 1924 | } |
| 1925 | err_map: |
| 1926 | kfree(hctxs); |
| 1927 | err_percpu: |
| 1928 | free_percpu(ctx); |
| 1929 | return ERR_PTR(-ENOMEM); |
| 1930 | } |
| 1931 | EXPORT_SYMBOL(blk_mq_init_queue); |
| 1932 | |
| 1933 | void blk_mq_free_queue(struct request_queue *q) |
| 1934 | { |
| 1935 | struct blk_mq_tag_set *set = q->tag_set; |
| 1936 | |
| 1937 | blk_mq_del_queue_tag_set(q); |
| 1938 | |
| 1939 | blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); |
| 1940 | blk_mq_free_hw_queues(q, set); |
| 1941 | |
| 1942 | percpu_ref_exit(&q->mq_usage_counter); |
| 1943 | |
| 1944 | free_percpu(q->queue_ctx); |
| 1945 | kfree(q->queue_hw_ctx); |
| 1946 | kfree(q->mq_map); |
| 1947 | |
| 1948 | q->queue_ctx = NULL; |
| 1949 | q->queue_hw_ctx = NULL; |
| 1950 | q->mq_map = NULL; |
| 1951 | |
| 1952 | mutex_lock(&all_q_mutex); |
| 1953 | list_del_init(&q->all_q_node); |
| 1954 | mutex_unlock(&all_q_mutex); |
| 1955 | } |
| 1956 | |
| 1957 | /* Basically redo blk_mq_init_queue with queue frozen */ |
| 1958 | static void blk_mq_queue_reinit(struct request_queue *q) |
| 1959 | { |
| 1960 | WARN_ON_ONCE(!q->mq_freeze_depth); |
| 1961 | |
| 1962 | blk_mq_sysfs_unregister(q); |
| 1963 | |
| 1964 | blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues); |
| 1965 | |
| 1966 | /* |
| 1967 | * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe |
| 1968 | * we should change hctx numa_node according to new topology (this |
| 1969 | * involves free and re-allocate memory, worthy doing?) |
| 1970 | */ |
| 1971 | |
| 1972 | blk_mq_map_swqueue(q); |
| 1973 | |
| 1974 | blk_mq_sysfs_register(q); |
| 1975 | } |
| 1976 | |
| 1977 | static int blk_mq_queue_reinit_notify(struct notifier_block *nb, |
| 1978 | unsigned long action, void *hcpu) |
| 1979 | { |
| 1980 | struct request_queue *q; |
| 1981 | |
| 1982 | /* |
| 1983 | * Before new mappings are established, hotadded cpu might already |
| 1984 | * start handling requests. This doesn't break anything as we map |
| 1985 | * offline CPUs to first hardware queue. We will re-init the queue |
| 1986 | * below to get optimal settings. |
| 1987 | */ |
| 1988 | if (action != CPU_DEAD && action != CPU_DEAD_FROZEN && |
| 1989 | action != CPU_ONLINE && action != CPU_ONLINE_FROZEN) |
| 1990 | return NOTIFY_OK; |
| 1991 | |
| 1992 | mutex_lock(&all_q_mutex); |
| 1993 | |
| 1994 | /* |
| 1995 | * We need to freeze and reinit all existing queues. Freezing |
| 1996 | * involves synchronous wait for an RCU grace period and doing it |
| 1997 | * one by one may take a long time. Start freezing all queues in |
| 1998 | * one swoop and then wait for the completions so that freezing can |
| 1999 | * take place in parallel. |
| 2000 | */ |
| 2001 | list_for_each_entry(q, &all_q_list, all_q_node) |
| 2002 | blk_mq_freeze_queue_start(q); |
| 2003 | list_for_each_entry(q, &all_q_list, all_q_node) |
| 2004 | blk_mq_freeze_queue_wait(q); |
| 2005 | |
| 2006 | list_for_each_entry(q, &all_q_list, all_q_node) |
| 2007 | blk_mq_queue_reinit(q); |
| 2008 | |
| 2009 | list_for_each_entry(q, &all_q_list, all_q_node) |
| 2010 | blk_mq_unfreeze_queue(q); |
| 2011 | |
| 2012 | mutex_unlock(&all_q_mutex); |
| 2013 | return NOTIFY_OK; |
| 2014 | } |
| 2015 | |
| 2016 | static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| 2017 | { |
| 2018 | int i; |
| 2019 | |
| 2020 | for (i = 0; i < set->nr_hw_queues; i++) { |
| 2021 | set->tags[i] = blk_mq_init_rq_map(set, i); |
| 2022 | if (!set->tags[i]) |
| 2023 | goto out_unwind; |
| 2024 | } |
| 2025 | |
| 2026 | return 0; |
| 2027 | |
| 2028 | out_unwind: |
| 2029 | while (--i >= 0) |
| 2030 | blk_mq_free_rq_map(set, set->tags[i], i); |
| 2031 | |
| 2032 | return -ENOMEM; |
| 2033 | } |
| 2034 | |
| 2035 | /* |
| 2036 | * Allocate the request maps associated with this tag_set. Note that this |
| 2037 | * may reduce the depth asked for, if memory is tight. set->queue_depth |
| 2038 | * will be updated to reflect the allocated depth. |
| 2039 | */ |
| 2040 | static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| 2041 | { |
| 2042 | unsigned int depth; |
| 2043 | int err; |
| 2044 | |
| 2045 | depth = set->queue_depth; |
| 2046 | do { |
| 2047 | err = __blk_mq_alloc_rq_maps(set); |
| 2048 | if (!err) |
| 2049 | break; |
| 2050 | |
| 2051 | set->queue_depth >>= 1; |
| 2052 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { |
| 2053 | err = -ENOMEM; |
| 2054 | break; |
| 2055 | } |
| 2056 | } while (set->queue_depth); |
| 2057 | |
| 2058 | if (!set->queue_depth || err) { |
| 2059 | pr_err("blk-mq: failed to allocate request map\n"); |
| 2060 | return -ENOMEM; |
| 2061 | } |
| 2062 | |
| 2063 | if (depth != set->queue_depth) |
| 2064 | pr_info("blk-mq: reduced tag depth (%u -> %u)\n", |
| 2065 | depth, set->queue_depth); |
| 2066 | |
| 2067 | return 0; |
| 2068 | } |
| 2069 | |
| 2070 | /* |
| 2071 | * Alloc a tag set to be associated with one or more request queues. |
| 2072 | * May fail with EINVAL for various error conditions. May adjust the |
| 2073 | * requested depth down, if if it too large. In that case, the set |
| 2074 | * value will be stored in set->queue_depth. |
| 2075 | */ |
| 2076 | int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) |
| 2077 | { |
| 2078 | BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); |
| 2079 | |
| 2080 | if (!set->nr_hw_queues) |
| 2081 | return -EINVAL; |
| 2082 | if (!set->queue_depth) |
| 2083 | return -EINVAL; |
| 2084 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) |
| 2085 | return -EINVAL; |
| 2086 | |
| 2087 | if (!set->nr_hw_queues || !set->ops->queue_rq || !set->ops->map_queue) |
| 2088 | return -EINVAL; |
| 2089 | |
| 2090 | if (set->queue_depth > BLK_MQ_MAX_DEPTH) { |
| 2091 | pr_info("blk-mq: reduced tag depth to %u\n", |
| 2092 | BLK_MQ_MAX_DEPTH); |
| 2093 | set->queue_depth = BLK_MQ_MAX_DEPTH; |
| 2094 | } |
| 2095 | |
| 2096 | /* |
| 2097 | * If a crashdump is active, then we are potentially in a very |
| 2098 | * memory constrained environment. Limit us to 1 queue and |
| 2099 | * 64 tags to prevent using too much memory. |
| 2100 | */ |
| 2101 | if (is_kdump_kernel()) { |
| 2102 | set->nr_hw_queues = 1; |
| 2103 | set->queue_depth = min(64U, set->queue_depth); |
| 2104 | } |
| 2105 | |
| 2106 | set->tags = kmalloc_node(set->nr_hw_queues * |
| 2107 | sizeof(struct blk_mq_tags *), |
| 2108 | GFP_KERNEL, set->numa_node); |
| 2109 | if (!set->tags) |
| 2110 | return -ENOMEM; |
| 2111 | |
| 2112 | if (blk_mq_alloc_rq_maps(set)) |
| 2113 | goto enomem; |
| 2114 | |
| 2115 | mutex_init(&set->tag_list_lock); |
| 2116 | INIT_LIST_HEAD(&set->tag_list); |
| 2117 | |
| 2118 | return 0; |
| 2119 | enomem: |
| 2120 | kfree(set->tags); |
| 2121 | set->tags = NULL; |
| 2122 | return -ENOMEM; |
| 2123 | } |
| 2124 | EXPORT_SYMBOL(blk_mq_alloc_tag_set); |
| 2125 | |
| 2126 | void blk_mq_free_tag_set(struct blk_mq_tag_set *set) |
| 2127 | { |
| 2128 | int i; |
| 2129 | |
| 2130 | for (i = 0; i < set->nr_hw_queues; i++) { |
| 2131 | if (set->tags[i]) |
| 2132 | blk_mq_free_rq_map(set, set->tags[i], i); |
| 2133 | } |
| 2134 | |
| 2135 | kfree(set->tags); |
| 2136 | set->tags = NULL; |
| 2137 | } |
| 2138 | EXPORT_SYMBOL(blk_mq_free_tag_set); |
| 2139 | |
| 2140 | int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) |
| 2141 | { |
| 2142 | struct blk_mq_tag_set *set = q->tag_set; |
| 2143 | struct blk_mq_hw_ctx *hctx; |
| 2144 | int i, ret; |
| 2145 | |
| 2146 | if (!set || nr > set->queue_depth) |
| 2147 | return -EINVAL; |
| 2148 | |
| 2149 | ret = 0; |
| 2150 | queue_for_each_hw_ctx(q, hctx, i) { |
| 2151 | ret = blk_mq_tag_update_depth(hctx->tags, nr); |
| 2152 | if (ret) |
| 2153 | break; |
| 2154 | } |
| 2155 | |
| 2156 | if (!ret) |
| 2157 | q->nr_requests = nr; |
| 2158 | |
| 2159 | return ret; |
| 2160 | } |
| 2161 | |
| 2162 | void blk_mq_disable_hotplug(void) |
| 2163 | { |
| 2164 | mutex_lock(&all_q_mutex); |
| 2165 | } |
| 2166 | |
| 2167 | void blk_mq_enable_hotplug(void) |
| 2168 | { |
| 2169 | mutex_unlock(&all_q_mutex); |
| 2170 | } |
| 2171 | |
| 2172 | static int __init blk_mq_init(void) |
| 2173 | { |
| 2174 | blk_mq_cpu_init(); |
| 2175 | |
| 2176 | hotcpu_notifier(blk_mq_queue_reinit_notify, 0); |
| 2177 | |
| 2178 | return 0; |
| 2179 | } |
| 2180 | subsys_initcall(blk_mq_init); |