blk-mq.c 33.9 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/smp.h>
#include <linux/llist.h>
#include <linux/list_sort.h>
#include <linux/cpu.h>
#include <linux/cache.h>
#include <linux/sched/sysctl.h>
#include <linux/delay.h>

#include <trace/events/block.h>

#include <linux/blk-mq.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-tag.h"

static DEFINE_MUTEX(all_q_mutex);
static LIST_HEAD(all_q_list);

static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx);

static struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
					   unsigned int cpu)
{
	return per_cpu_ptr(q->queue_ctx, cpu);
}

/*
 * This assumes per-cpu software queueing queues. They could be per-node
 * as well, for instance. For now this is hardcoded as-is. Note that we don't
 * care about preemption, since we know the ctx's are persistent. This does
 * mean that we can't rely on ctx always matching the currently running CPU.
 */
static struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
{
	return __blk_mq_get_ctx(q, get_cpu());
}

static void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
{
	put_cpu();
}

/*
 * Check if any of the ctx's have pending work in this hardware queue
 */
static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
{
	unsigned int i;

	for (i = 0; i < hctx->nr_ctx_map; i++)
		if (hctx->ctx_map[i])
			return true;

	return false;
}

/*
 * Mark this ctx as having pending work in this hardware queue
 */
static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
				     struct blk_mq_ctx *ctx)
{
	if (!test_bit(ctx->index_hw, hctx->ctx_map))
		set_bit(ctx->index_hw, hctx->ctx_map);
}

76 77
static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
					      gfp_t gfp, bool reserved)
78 79 80 81 82 83 84
{
	struct request *rq;
	unsigned int tag;

	tag = blk_mq_get_tag(hctx->tags, gfp, reserved);
	if (tag != BLK_MQ_TAG_FAIL) {
		rq = hctx->rqs[tag];
85
		blk_rq_init(hctx->queue, rq);
86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107
		rq->tag = tag;

		return rq;
	}

	return NULL;
}

static int blk_mq_queue_enter(struct request_queue *q)
{
	int ret;

	__percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
	smp_wmb();
	/* we have problems to freeze the queue if it's initializing */
	if (!blk_queue_bypass(q) || !blk_queue_init_done(q))
		return 0;

	__percpu_counter_add(&q->mq_usage_counter, -1, 1000000);

	spin_lock_irq(q->queue_lock);
	ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq,
108 109
		!blk_queue_bypass(q) || blk_queue_dying(q),
		*q->queue_lock);
110
	/* inc usage with lock hold to avoid freeze_queue runs here */
111
	if (!ret && !blk_queue_dying(q))
112
		__percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
113 114
	else if (blk_queue_dying(q))
		ret = -ENODEV;
115 116 117 118 119 120 121 122 123 124
	spin_unlock_irq(q->queue_lock);

	return ret;
}

static void blk_mq_queue_exit(struct request_queue *q)
{
	__percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
}

125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
static void __blk_mq_drain_queue(struct request_queue *q)
{
	while (true) {
		s64 count;

		spin_lock_irq(q->queue_lock);
		count = percpu_counter_sum(&q->mq_usage_counter);
		spin_unlock_irq(q->queue_lock);

		if (count == 0)
			break;
		blk_mq_run_queues(q, false);
		msleep(10);
	}
}

141 142 143 144 145 146 147 148 149 150 151 152 153
/*
 * Guarantee no request is in use, so we can change any data structure of
 * the queue afterward.
 */
static void blk_mq_freeze_queue(struct request_queue *q)
{
	bool drain;

	spin_lock_irq(q->queue_lock);
	drain = !q->bypass_depth++;
	queue_flag_set(QUEUE_FLAG_BYPASS, q);
	spin_unlock_irq(q->queue_lock);

154 155 156
	if (drain)
		__blk_mq_drain_queue(q);
}
157

158 159 160
void blk_mq_drain_queue(struct request_queue *q)
{
	__blk_mq_drain_queue(q);
161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183
}

static void blk_mq_unfreeze_queue(struct request_queue *q)
{
	bool wake = false;

	spin_lock_irq(q->queue_lock);
	if (!--q->bypass_depth) {
		queue_flag_clear(QUEUE_FLAG_BYPASS, q);
		wake = true;
	}
	WARN_ON_ONCE(q->bypass_depth < 0);
	spin_unlock_irq(q->queue_lock);
	if (wake)
		wake_up_all(&q->mq_freeze_wq);
}

bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
{
	return blk_mq_has_free_tags(hctx->tags);
}
EXPORT_SYMBOL(blk_mq_can_queue);

184 185
static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
			       struct request *rq, unsigned int rw_flags)
186
{
187 188 189
	if (blk_queue_io_stat(q))
		rw_flags |= REQ_IO_STAT;

190 191
	rq->mq_ctx = ctx;
	rq->cmd_flags = rw_flags;
192 193
	rq->start_time = jiffies;
	set_start_time_ns(rq);
194 195 196 197 198 199 200 201 202 203 204 205 206
	ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
}

static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
						   int rw, gfp_t gfp,
						   bool reserved)
{
	struct request *rq;

	do {
		struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
		struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);

207
		rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved);
208
		if (rq) {
209
			blk_mq_rq_ctx_init(q, ctx, rq, rw);
210
			break;
211
		}
212

213 214 215 216 217
		if (gfp & __GFP_WAIT) {
			__blk_mq_run_hw_queue(hctx);
			blk_mq_put_ctx(ctx);
		} else {
			blk_mq_put_ctx(ctx);
218
			break;
219
		}
220

221 222 223 224 225 226
		blk_mq_wait_for_tags(hctx->tags);
	} while (1);

	return rq;
}

227
struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp)
228 229 230 231 232 233
{
	struct request *rq;

	if (blk_mq_queue_enter(q))
		return NULL;

234
	rq = blk_mq_alloc_request_pinned(q, rw, gfp, false);
235 236
	if (rq)
		blk_mq_put_ctx(rq->mq_ctx);
237 238 239 240 241 242 243 244 245 246 247 248
	return rq;
}

struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw,
					      gfp_t gfp)
{
	struct request *rq;

	if (blk_mq_queue_enter(q))
		return NULL;

	rq = blk_mq_alloc_request_pinned(q, rw, gfp, true);
249 250
	if (rq)
		blk_mq_put_ctx(rq->mq_ctx);
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276
	return rq;
}
EXPORT_SYMBOL(blk_mq_alloc_reserved_request);

static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
				  struct blk_mq_ctx *ctx, struct request *rq)
{
	const int tag = rq->tag;
	struct request_queue *q = rq->q;

	blk_mq_put_tag(hctx->tags, tag);
	blk_mq_queue_exit(q);
}

void blk_mq_free_request(struct request *rq)
{
	struct blk_mq_ctx *ctx = rq->mq_ctx;
	struct blk_mq_hw_ctx *hctx;
	struct request_queue *q = rq->q;

	ctx->rq_completed[rq_is_sync(rq)]++;

	hctx = q->mq_ops->map_queue(q, ctx->cpu);
	__blk_mq_free_request(hctx, ctx, rq);
}

277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296
/*
 * Clone all relevant state from a request that has been put on hold in
 * the flush state machine into the preallocated flush request that hangs
 * off the request queue.
 *
 * For a driver the flush request should be invisible, that's why we are
 * impersonating the original request here.
 */
void blk_mq_clone_flush_request(struct request *flush_rq,
		struct request *orig_rq)
{
	struct blk_mq_hw_ctx *hctx =
		orig_rq->q->mq_ops->map_queue(orig_rq->q, orig_rq->mq_ctx->cpu);

	flush_rq->mq_ctx = orig_rq->mq_ctx;
	flush_rq->tag = orig_rq->tag;
	memcpy(blk_mq_rq_to_pdu(flush_rq), blk_mq_rq_to_pdu(orig_rq),
		hctx->cmd_size);
}

297
bool blk_mq_end_io_partial(struct request *rq, int error, unsigned int nr_bytes)
298
{
299 300
	if (blk_update_request(rq, error, blk_rq_bytes(rq)))
		return true;
301

M
Ming Lei 已提交
302 303
	blk_account_io_done(rq);

304 305 306 307
	if (rq->end_io)
		rq->end_io(rq, error);
	else
		blk_mq_free_request(rq);
308
	return false;
309
}
310
EXPORT_SYMBOL(blk_mq_end_io_partial);
311

312
static void __blk_mq_complete_request_remote(void *data)
313
{
314
	struct request *rq = data;
315

316
	rq->q->softirq_done_fn(rq);
317 318
}

319
void __blk_mq_complete_request(struct request *rq)
320 321 322 323
{
	struct blk_mq_ctx *ctx = rq->mq_ctx;
	int cpu;

324 325 326 327
	if (!ctx->ipi_redirect) {
		rq->q->softirq_done_fn(rq);
		return;
	}
328 329

	cpu = get_cpu();
330
	if (cpu != ctx->cpu && cpu_online(ctx->cpu)) {
331
		rq->csd.func = __blk_mq_complete_request_remote;
332 333
		rq->csd.info = rq;
		rq->csd.flags = 0;
334
		smp_call_function_single_async(ctx->cpu, &rq->csd);
335
	} else {
336
		rq->q->softirq_done_fn(rq);
337
	}
338 339
	put_cpu();
}
340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356

/**
 * blk_mq_complete_request - end I/O on a request
 * @rq:		the request being processed
 *
 * Description:
 *	Ends all I/O on a request. It does not handle partial completions.
 *	The actual completion happens out-of-order, through a IPI handler.
 **/
void blk_mq_complete_request(struct request *rq)
{
	if (unlikely(blk_should_fake_timeout(rq->q)))
		return;
	if (!blk_mark_rq_complete(rq))
		__blk_mq_complete_request(rq);
}
EXPORT_SYMBOL(blk_mq_complete_request);
357

358
static void blk_mq_start_request(struct request *rq, bool last)
359 360 361 362 363
{
	struct request_queue *q = rq->q;

	trace_block_rq_issue(q, rq);

C
Christoph Hellwig 已提交
364 365
	rq->resid_len = blk_rq_bytes(rq);

366 367 368 369 370 371 372
	/*
	 * Just mark start time and set the started bit. Due to memory
	 * ordering, we know we'll see the correct deadline as long as
	 * REQ_ATOMIC_STARTED is seen.
	 */
	rq->deadline = jiffies + q->rq_timeout;
	set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391

	if (q->dma_drain_size && blk_rq_bytes(rq)) {
		/*
		 * Make sure space for the drain appears.  We know we can do
		 * this because max_hw_segments has been adjusted to be one
		 * fewer than the device can handle.
		 */
		rq->nr_phys_segments++;
	}

	/*
	 * Flag the last request in the series so that drivers know when IO
	 * should be kicked off, if they don't do it on a per-request basis.
	 *
	 * Note: the flag isn't the only condition drivers should do kick off.
	 * If drive is busy, the last request might not have the bit set.
	 */
	if (last)
		rq->cmd_flags |= REQ_END;
392 393 394 395 396 397 398 399
}

static void blk_mq_requeue_request(struct request *rq)
{
	struct request_queue *q = rq->q;

	trace_block_rq_requeue(q, rq);
	clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
400 401 402 403 404

	rq->cmd_flags &= ~REQ_END;

	if (q->dma_drain_size && blk_rq_bytes(rq))
		rq->nr_phys_segments--;
405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529
}

struct blk_mq_timeout_data {
	struct blk_mq_hw_ctx *hctx;
	unsigned long *next;
	unsigned int *next_set;
};

static void blk_mq_timeout_check(void *__data, unsigned long *free_tags)
{
	struct blk_mq_timeout_data *data = __data;
	struct blk_mq_hw_ctx *hctx = data->hctx;
	unsigned int tag;

	 /* It may not be in flight yet (this is where
	 * the REQ_ATOMIC_STARTED flag comes in). The requests are
	 * statically allocated, so we know it's always safe to access the
	 * memory associated with a bit offset into ->rqs[].
	 */
	tag = 0;
	do {
		struct request *rq;

		tag = find_next_zero_bit(free_tags, hctx->queue_depth, tag);
		if (tag >= hctx->queue_depth)
			break;

		rq = hctx->rqs[tag++];

		if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
			continue;

		blk_rq_check_expired(rq, data->next, data->next_set);
	} while (1);
}

static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx *hctx,
					unsigned long *next,
					unsigned int *next_set)
{
	struct blk_mq_timeout_data data = {
		.hctx		= hctx,
		.next		= next,
		.next_set	= next_set,
	};

	/*
	 * Ask the tagging code to iterate busy requests, so we can
	 * check them for timeout.
	 */
	blk_mq_tag_busy_iter(hctx->tags, blk_mq_timeout_check, &data);
}

static void blk_mq_rq_timer(unsigned long data)
{
	struct request_queue *q = (struct request_queue *) data;
	struct blk_mq_hw_ctx *hctx;
	unsigned long next = 0;
	int i, next_set = 0;

	queue_for_each_hw_ctx(q, hctx, i)
		blk_mq_hw_ctx_check_timeout(hctx, &next, &next_set);

	if (next_set)
		mod_timer(&q->timeout, round_jiffies_up(next));
}

/*
 * Reverse check our software queue for entries that we could potentially
 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
 * too much time checking for merges.
 */
static bool blk_mq_attempt_merge(struct request_queue *q,
				 struct blk_mq_ctx *ctx, struct bio *bio)
{
	struct request *rq;
	int checked = 8;

	list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
		int el_ret;

		if (!checked--)
			break;

		if (!blk_rq_merge_ok(rq, bio))
			continue;

		el_ret = blk_try_merge(rq, bio);
		if (el_ret == ELEVATOR_BACK_MERGE) {
			if (bio_attempt_back_merge(q, rq, bio)) {
				ctx->rq_merged++;
				return true;
			}
			break;
		} else if (el_ret == ELEVATOR_FRONT_MERGE) {
			if (bio_attempt_front_merge(q, rq, bio)) {
				ctx->rq_merged++;
				return true;
			}
			break;
		}
	}

	return false;
}

void blk_mq_add_timer(struct request *rq)
{
	__blk_add_timer(rq, NULL);
}

/*
 * Run this hardware queue, pulling any software queues mapped to it in.
 * Note that this function currently has various problems around ordering
 * of IO. In particular, we'd like FIFO behaviour on handling existing
 * items on the hctx->dispatch list. Ignore that for now.
 */
static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
{
	struct request_queue *q = hctx->queue;
	struct blk_mq_ctx *ctx;
	struct request *rq;
	LIST_HEAD(rq_list);
	int bit, queued;

530 531
	WARN_ON(!preempt_count());

532
	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574
		return;

	hctx->run++;

	/*
	 * Touch any software queue that has pending entries.
	 */
	for_each_set_bit(bit, hctx->ctx_map, hctx->nr_ctx) {
		clear_bit(bit, hctx->ctx_map);
		ctx = hctx->ctxs[bit];
		BUG_ON(bit != ctx->index_hw);

		spin_lock(&ctx->lock);
		list_splice_tail_init(&ctx->rq_list, &rq_list);
		spin_unlock(&ctx->lock);
	}

	/*
	 * If we have previous entries on our dispatch list, grab them
	 * and stuff them at the front for more fair dispatch.
	 */
	if (!list_empty_careful(&hctx->dispatch)) {
		spin_lock(&hctx->lock);
		if (!list_empty(&hctx->dispatch))
			list_splice_init(&hctx->dispatch, &rq_list);
		spin_unlock(&hctx->lock);
	}

	/*
	 * Delete and return all entries from our dispatch list
	 */
	queued = 0;

	/*
	 * Now process all the entries, sending them to the driver.
	 */
	while (!list_empty(&rq_list)) {
		int ret;

		rq = list_first_entry(&rq_list, struct request, queuelist);
		list_del_init(&rq->queuelist);

575
		blk_mq_start_request(rq, list_empty(&rq_list));
576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593

		ret = q->mq_ops->queue_rq(hctx, rq);
		switch (ret) {
		case BLK_MQ_RQ_QUEUE_OK:
			queued++;
			continue;
		case BLK_MQ_RQ_QUEUE_BUSY:
			/*
			 * FIXME: we should have a mechanism to stop the queue
			 * like blk_stop_queue, otherwise we will waste cpu
			 * time
			 */
			list_add(&rq->queuelist, &rq_list);
			blk_mq_requeue_request(rq);
			break;
		default:
			pr_err("blk-mq: bad return on queue: %d\n", ret);
		case BLK_MQ_RQ_QUEUE_ERROR:
594
			rq->errors = -EIO;
595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
			blk_mq_end_io(rq, rq->errors);
			break;
		}

		if (ret == BLK_MQ_RQ_QUEUE_BUSY)
			break;
	}

	if (!queued)
		hctx->dispatched[0]++;
	else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1)))
		hctx->dispatched[ilog2(queued) + 1]++;

	/*
	 * Any items that need requeuing? Stuff them into hctx->dispatch,
	 * that is where we will continue on next queue run.
	 */
	if (!list_empty(&rq_list)) {
		spin_lock(&hctx->lock);
		list_splice(&rq_list, &hctx->dispatch);
		spin_unlock(&hctx->lock);
	}
}

void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
{
621
	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
622 623
		return;

624
	if (!async && cpumask_test_cpu(smp_processor_id(), hctx->cpumask))
625
		__blk_mq_run_hw_queue(hctx);
626
	else if (hctx->queue->nr_hw_queues == 1)
627
		kblockd_schedule_delayed_work(&hctx->delayed_work, 0);
628 629 630 631 632 633 634 635 636 637 638 639
	else {
		unsigned int cpu;

		/*
		 * It'd be great if the workqueue API had a way to pass
		 * in a mask and had some smarts for more clever placement
		 * than the first CPU. Or we could round-robin here. For now,
		 * just queue on the first CPU.
		 */
		cpu = cpumask_first(hctx->cpumask);
		kblockd_schedule_delayed_work_on(cpu, &hctx->delayed_work, 0);
	}
640 641 642 643 644 645 646 647 648 649
}

void blk_mq_run_queues(struct request_queue *q, bool async)
{
	struct blk_mq_hw_ctx *hctx;
	int i;

	queue_for_each_hw_ctx(q, hctx, i) {
		if ((!blk_mq_hctx_has_pending(hctx) &&
		    list_empty_careful(&hctx->dispatch)) ||
650
		    test_bit(BLK_MQ_S_STOPPED, &hctx->state))
651 652
			continue;

653
		preempt_disable();
654
		blk_mq_run_hw_queue(hctx, async);
655
		preempt_enable();
656 657 658 659 660 661 662 663 664 665 666
	}
}
EXPORT_SYMBOL(blk_mq_run_queues);

void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
	cancel_delayed_work(&hctx->delayed_work);
	set_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queue);

667 668 669 670 671 672 673 674 675 676
void blk_mq_stop_hw_queues(struct request_queue *q)
{
	struct blk_mq_hw_ctx *hctx;
	int i;

	queue_for_each_hw_ctx(q, hctx, i)
		blk_mq_stop_hw_queue(hctx);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queues);

677 678 679
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
{
	clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
680 681

	preempt_disable();
682
	__blk_mq_run_hw_queue(hctx);
683
	preempt_enable();
684 685 686 687 688 689 690 691 692 693 694 695 696
}
EXPORT_SYMBOL(blk_mq_start_hw_queue);

void blk_mq_start_stopped_hw_queues(struct request_queue *q)
{
	struct blk_mq_hw_ctx *hctx;
	int i;

	queue_for_each_hw_ctx(q, hctx, i) {
		if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state))
			continue;

		clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
697
		preempt_disable();
698
		blk_mq_run_hw_queue(hctx, true);
699
		preempt_enable();
700 701 702 703 704 705 706 707 708
	}
}
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);

static void blk_mq_work_fn(struct work_struct *work)
{
	struct blk_mq_hw_ctx *hctx;

	hctx = container_of(work, struct blk_mq_hw_ctx, delayed_work.work);
709 710

	preempt_disable();
711
	__blk_mq_run_hw_queue(hctx);
712
	preempt_enable();
713 714 715
}

static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
716
				    struct request *rq, bool at_head)
717 718 719
{
	struct blk_mq_ctx *ctx = rq->mq_ctx;

720 721
	trace_block_rq_insert(hctx->queue, rq);

722 723 724 725
	if (at_head)
		list_add(&rq->queuelist, &ctx->rq_list);
	else
		list_add_tail(&rq->queuelist, &ctx->rq_list);
726 727 728 729 730 731 732 733
	blk_mq_hctx_mark_pending(hctx, ctx);

	/*
	 * We do this early, to ensure we are on the right CPU.
	 */
	blk_mq_add_timer(rq);
}

734 735
void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
		bool async)
736
{
737
	struct request_queue *q = rq->q;
738
	struct blk_mq_hw_ctx *hctx;
739 740 741 742 743
	struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx;

	current_ctx = blk_mq_get_ctx(q);
	if (!cpu_online(ctx->cpu))
		rq->mq_ctx = ctx = current_ctx;
744 745 746

	hctx = q->mq_ops->map_queue(q, ctx->cpu);

747 748
	if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA) &&
	    !(rq->cmd_flags & (REQ_FLUSH_SEQ))) {
749 750 751
		blk_insert_flush(rq);
	} else {
		spin_lock(&ctx->lock);
752
		__blk_mq_insert_request(hctx, rq, at_head);
753 754 755 756 757
		spin_unlock(&ctx->lock);
	}

	if (run_queue)
		blk_mq_run_hw_queue(hctx, async);
758 759

	blk_mq_put_ctx(current_ctx);
760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790
}

static void blk_mq_insert_requests(struct request_queue *q,
				     struct blk_mq_ctx *ctx,
				     struct list_head *list,
				     int depth,
				     bool from_schedule)

{
	struct blk_mq_hw_ctx *hctx;
	struct blk_mq_ctx *current_ctx;

	trace_block_unplug(q, depth, !from_schedule);

	current_ctx = blk_mq_get_ctx(q);

	if (!cpu_online(ctx->cpu))
		ctx = current_ctx;
	hctx = q->mq_ops->map_queue(q, ctx->cpu);

	/*
	 * preemption doesn't flush plug list, so it's possible ctx->cpu is
	 * offline now
	 */
	spin_lock(&ctx->lock);
	while (!list_empty(list)) {
		struct request *rq;

		rq = list_first_entry(list, struct request, queuelist);
		list_del_init(&rq->queuelist);
		rq->mq_ctx = ctx;
791
		__blk_mq_insert_request(hctx, rq, false);
792 793 794 795
	}
	spin_unlock(&ctx->lock);

	blk_mq_run_hw_queue(hctx, from_schedule);
796
	blk_mq_put_ctx(current_ctx);
797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879
}

static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct request *rqa = container_of(a, struct request, queuelist);
	struct request *rqb = container_of(b, struct request, queuelist);

	return !(rqa->mq_ctx < rqb->mq_ctx ||
		 (rqa->mq_ctx == rqb->mq_ctx &&
		  blk_rq_pos(rqa) < blk_rq_pos(rqb)));
}

void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
	struct blk_mq_ctx *this_ctx;
	struct request_queue *this_q;
	struct request *rq;
	LIST_HEAD(list);
	LIST_HEAD(ctx_list);
	unsigned int depth;

	list_splice_init(&plug->mq_list, &list);

	list_sort(NULL, &list, plug_ctx_cmp);

	this_q = NULL;
	this_ctx = NULL;
	depth = 0;

	while (!list_empty(&list)) {
		rq = list_entry_rq(list.next);
		list_del_init(&rq->queuelist);
		BUG_ON(!rq->q);
		if (rq->mq_ctx != this_ctx) {
			if (this_ctx) {
				blk_mq_insert_requests(this_q, this_ctx,
							&ctx_list, depth,
							from_schedule);
			}

			this_ctx = rq->mq_ctx;
			this_q = rq->q;
			depth = 0;
		}

		depth++;
		list_add_tail(&rq->queuelist, &ctx_list);
	}

	/*
	 * If 'this_ctx' is set, we know we have entries to complete
	 * on 'ctx_list'. Do those.
	 */
	if (this_ctx) {
		blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth,
				       from_schedule);
	}
}

static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
{
	init_request_from_bio(rq, bio);
	blk_account_io_start(rq, 1);
}

static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
{
	struct blk_mq_hw_ctx *hctx;
	struct blk_mq_ctx *ctx;
	const int is_sync = rw_is_sync(bio->bi_rw);
	const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA);
	int rw = bio_data_dir(bio);
	struct request *rq;
	unsigned int use_plug, request_count = 0;

	/*
	 * If we have multiple hardware queues, just go directly to
	 * one of those for sync IO.
	 */
	use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync);

	blk_queue_bounce(q, &bio);

880 881 882 883 884
	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
		bio_endio(bio, -EIO);
		return;
	}

885 886 887 888 889 890 891 892 893 894 895
	if (use_plug && blk_attempt_plug_merge(q, bio, &request_count))
		return;

	if (blk_mq_queue_enter(q)) {
		bio_endio(bio, -EIO);
		return;
	}

	ctx = blk_mq_get_ctx(q);
	hctx = q->mq_ops->map_queue(q, ctx->cpu);

S
Shaohua Li 已提交
896 897
	if (is_sync)
		rw |= REQ_SYNC;
898
	trace_block_getrq(q, bio, rw);
899
	rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false);
900
	if (likely(rq))
901
		blk_mq_rq_ctx_init(q, ctx, rq, rw);
902 903 904
	else {
		blk_mq_put_ctx(ctx);
		trace_block_sleeprq(q, bio, rw);
905 906
		rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC,
							false);
907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928
		ctx = rq->mq_ctx;
		hctx = q->mq_ops->map_queue(q, ctx->cpu);
	}

	hctx->queued++;

	if (unlikely(is_flush_fua)) {
		blk_mq_bio_to_request(rq, bio);
		blk_insert_flush(rq);
		goto run_queue;
	}

	/*
	 * A task plug currently exists. Since this is completely lockless,
	 * utilize that to temporarily store requests until the task is
	 * either done or scheduled away.
	 */
	if (use_plug) {
		struct blk_plug *plug = current->plug;

		if (plug) {
			blk_mq_bio_to_request(rq, bio);
S
Shaohua Li 已提交
929
			if (list_empty(&plug->mq_list))
930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947
				trace_block_plug(q);
			else if (request_count >= BLK_MAX_REQUEST_COUNT) {
				blk_flush_plug_list(plug, false);
				trace_block_plug(q);
			}
			list_add_tail(&rq->queuelist, &plug->mq_list);
			blk_mq_put_ctx(ctx);
			return;
		}
	}

	spin_lock(&ctx->lock);

	if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
	    blk_mq_attempt_merge(q, ctx, bio))
		__blk_mq_free_request(hctx, ctx, rq);
	else {
		blk_mq_bio_to_request(rq, bio);
948
		__blk_mq_insert_request(hctx, rq, false);
949 950 951 952 953 954 955 956 957 958 959
	}

	spin_unlock(&ctx->lock);

	/*
	 * For a SYNC request, send it to the hardware immediately. For an
	 * ASYNC request, just ensure that we run it later on. The latter
	 * allows for merging opportunities and more efficient dispatching.
	 */
run_queue:
	blk_mq_run_hw_queue(hctx, !is_sync || is_flush_fua);
960
	blk_mq_put_ctx(ctx);
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990
}

/*
 * Default mapping to a software queue, since we use one per CPU.
 */
struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, const int cpu)
{
	return q->queue_hw_ctx[q->mq_map[cpu]];
}
EXPORT_SYMBOL(blk_mq_map_queue);

struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_reg *reg,
						   unsigned int hctx_index)
{
	return kmalloc_node(sizeof(struct blk_mq_hw_ctx),
				GFP_KERNEL | __GFP_ZERO, reg->numa_node);
}
EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue);

void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *hctx,
				 unsigned int hctx_index)
{
	kfree(hctx);
}
EXPORT_SYMBOL(blk_mq_free_single_hw_queue);

static void blk_mq_hctx_notify(void *data, unsigned long action,
			       unsigned int cpu)
{
	struct blk_mq_hw_ctx *hctx = data;
991
	struct request_queue *q = hctx->queue;
992 993 994 995 996 997 998 999 1000
	struct blk_mq_ctx *ctx;
	LIST_HEAD(tmp);

	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
		return;

	/*
	 * Move ctx entries to new CPU, if this one is going away.
	 */
1001
	ctx = __blk_mq_get_ctx(q, cpu);
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012

	spin_lock(&ctx->lock);
	if (!list_empty(&ctx->rq_list)) {
		list_splice_init(&ctx->rq_list, &tmp);
		clear_bit(ctx->index_hw, hctx->ctx_map);
	}
	spin_unlock(&ctx->lock);

	if (list_empty(&tmp))
		return;

1013
	ctx = blk_mq_get_ctx(q);
1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
	spin_lock(&ctx->lock);

	while (!list_empty(&tmp)) {
		struct request *rq;

		rq = list_first_entry(&tmp, struct request, queuelist);
		rq->mq_ctx = ctx;
		list_move_tail(&rq->queuelist, &ctx->rq_list);
	}

1024
	hctx = q->mq_ops->map_queue(q, ctx->cpu);
1025 1026 1027
	blk_mq_hctx_mark_pending(hctx, ctx);

	spin_unlock(&ctx->lock);
1028 1029

	blk_mq_run_hw_queue(hctx, true);
1030
	blk_mq_put_ctx(ctx);
1031 1032
}

1033
static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx, void *driver_data)
1034
{
1035
	struct page *page;
1036

1037 1038
	if (hctx->rqs && hctx->queue->mq_ops->exit_request) {
		int i;
1039

1040 1041 1042 1043 1044 1045
		for (i = 0; i < hctx->queue_depth; i++) {
			if (!hctx->rqs[i])
				continue;
			hctx->queue->mq_ops->exit_request(driver_data, hctx,
							  hctx->rqs[i], i);
		}
1046 1047 1048
	}

	while (!list_empty(&hctx->page_list)) {
1049 1050
		page = list_first_entry(&hctx->page_list, struct page, lru);
		list_del_init(&page->lru);
1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
		__free_pages(page, page->private);
	}

	kfree(hctx->rqs);

	if (hctx->tags)
		blk_mq_free_tags(hctx->tags);
}

static size_t order_to_size(unsigned int order)
{
	size_t ret = PAGE_SIZE;

	while (order--)
		ret *= 2;

	return ret;
}

static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
1071
		struct blk_mq_reg *reg, void *driver_data, int node)
1072
{
1073
	unsigned int reserved_tags = reg->reserved_tags;
1074 1075
	unsigned int i, j, entries_per_page, max_order = 4;
	size_t rq_size, left;
1076
	int error;
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115

	INIT_LIST_HEAD(&hctx->page_list);

	hctx->rqs = kmalloc_node(hctx->queue_depth * sizeof(struct request *),
					GFP_KERNEL, node);
	if (!hctx->rqs)
		return -ENOMEM;

	/*
	 * rq_size is the size of the request plus driver payload, rounded
	 * to the cacheline size
	 */
	rq_size = round_up(sizeof(struct request) + hctx->cmd_size,
				cache_line_size());
	left = rq_size * hctx->queue_depth;

	for (i = 0; i < hctx->queue_depth;) {
		int this_order = max_order;
		struct page *page;
		int to_do;
		void *p;

		while (left < order_to_size(this_order - 1) && this_order)
			this_order--;

		do {
			page = alloc_pages_node(node, GFP_KERNEL, this_order);
			if (page)
				break;
			if (!this_order--)
				break;
			if (order_to_size(this_order) < rq_size)
				break;
		} while (1);

		if (!page)
			break;

		page->private = this_order;
1116
		list_add_tail(&page->lru, &hctx->page_list);
1117 1118 1119 1120 1121 1122 1123

		p = page_address(page);
		entries_per_page = order_to_size(this_order) / rq_size;
		to_do = min(entries_per_page, hctx->queue_depth - i);
		left -= to_do * rq_size;
		for (j = 0; j < to_do; j++) {
			hctx->rqs[i] = p;
1124 1125 1126 1127 1128 1129 1130
			if (reg->ops->init_request) {
				error = reg->ops->init_request(driver_data,
						hctx, hctx->rqs[i], i);
				if (error)
					goto err_rq_map;
			}

1131 1132 1133 1134 1135
			p += rq_size;
			i++;
		}
	}

1136 1137
	if (i < (reserved_tags + BLK_MQ_TAG_MIN)) {
		error = -ENOMEM;
1138
		goto err_rq_map;
1139 1140
	}
	if (i != hctx->queue_depth) {
1141 1142 1143 1144 1145 1146 1147
		hctx->queue_depth = i;
		pr_warn("%s: queue depth set to %u because of low memory\n",
					__func__, i);
	}

	hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
	if (!hctx->tags) {
1148 1149
		error = -ENOMEM;
		goto err_rq_map;
1150 1151 1152
	}

	return 0;
1153 1154 1155
err_rq_map:
	blk_mq_free_rq_map(hctx, driver_data);
	return error;
1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
}

static int blk_mq_init_hw_queues(struct request_queue *q,
				 struct blk_mq_reg *reg, void *driver_data)
{
	struct blk_mq_hw_ctx *hctx;
	unsigned int i, j;

	/*
	 * Initialize hardware queues
	 */
	queue_for_each_hw_ctx(q, hctx, i) {
		unsigned int num_maps;
		int node;

		node = hctx->numa_node;
		if (node == NUMA_NO_NODE)
			node = hctx->numa_node = reg->numa_node;

		INIT_DELAYED_WORK(&hctx->delayed_work, blk_mq_work_fn);
		spin_lock_init(&hctx->lock);
		INIT_LIST_HEAD(&hctx->dispatch);
		hctx->queue = q;
		hctx->queue_num = i;
		hctx->flags = reg->flags;
		hctx->queue_depth = reg->queue_depth;
		hctx->cmd_size = reg->cmd_size;

		blk_mq_init_cpu_notifier(&hctx->cpu_notifier,
						blk_mq_hctx_notify, hctx);
		blk_mq_register_cpu_notifier(&hctx->cpu_notifier);

1188
		if (blk_mq_init_rq_map(hctx, reg, driver_data, node))
1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
			break;

		/*
		 * Allocate space for all possible cpus to avoid allocation in
		 * runtime
		 */
		hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
						GFP_KERNEL, node);
		if (!hctx->ctxs)
			break;

		num_maps = ALIGN(nr_cpu_ids, BITS_PER_LONG) / BITS_PER_LONG;
		hctx->ctx_map = kzalloc_node(num_maps * sizeof(unsigned long),
						GFP_KERNEL, node);
		if (!hctx->ctx_map)
			break;

		hctx->nr_ctx_map = num_maps;
		hctx->nr_ctx = 0;

		if (reg->ops->init_hctx &&
		    reg->ops->init_hctx(hctx, driver_data, i))
			break;
	}

	if (i == q->nr_hw_queues)
		return 0;

	/*
	 * Init failed
	 */
	queue_for_each_hw_ctx(q, hctx, j) {
		if (i == j)
			break;

		if (reg->ops->exit_hctx)
			reg->ops->exit_hctx(hctx, j);

		blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
1228
		blk_mq_free_rq_map(hctx, driver_data);
1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253
		kfree(hctx->ctxs);
	}

	return 1;
}

static void blk_mq_init_cpu_queues(struct request_queue *q,
				   unsigned int nr_hw_queues)
{
	unsigned int i;

	for_each_possible_cpu(i) {
		struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
		struct blk_mq_hw_ctx *hctx;

		memset(__ctx, 0, sizeof(*__ctx));
		__ctx->cpu = i;
		spin_lock_init(&__ctx->lock);
		INIT_LIST_HEAD(&__ctx->rq_list);
		__ctx->queue = q;

		/* If the cpu isn't online, the cpu is mapped to first hctx */
		if (!cpu_online(i))
			continue;

1254 1255 1256 1257
		hctx = q->mq_ops->map_queue(q, i);
		cpumask_set_cpu(i, hctx->cpumask);
		hctx->nr_ctx++;

1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
		/*
		 * Set local node, IFF we have more than one hw queue. If
		 * not, we remain on the home node of the device
		 */
		if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
			hctx->numa_node = cpu_to_node(i);
	}
}

static void blk_mq_map_swqueue(struct request_queue *q)
{
	unsigned int i;
	struct blk_mq_hw_ctx *hctx;
	struct blk_mq_ctx *ctx;

	queue_for_each_hw_ctx(q, hctx, i) {
1274
		cpumask_clear(hctx->cpumask);
1275 1276 1277 1278 1279 1280 1281 1282
		hctx->nr_ctx = 0;
	}

	/*
	 * Map software to hardware queues
	 */
	queue_for_each_ctx(q, ctx, i) {
		/* If the cpu isn't online, the cpu is mapped to first hctx */
1283 1284 1285
		if (!cpu_online(i))
			continue;

1286
		hctx = q->mq_ops->map_queue(q, i);
1287
		cpumask_set_cpu(i, hctx->cpumask);
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
		ctx->index_hw = hctx->nr_ctx;
		hctx->ctxs[hctx->nr_ctx++] = ctx;
	}
}

struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,
					void *driver_data)
{
	struct blk_mq_hw_ctx **hctxs;
	struct blk_mq_ctx *ctx;
	struct request_queue *q;
	int i;

	if (!reg->nr_hw_queues ||
	    !reg->ops->queue_rq || !reg->ops->map_queue ||
	    !reg->ops->alloc_hctx || !reg->ops->free_hctx)
		return ERR_PTR(-EINVAL);

	if (!reg->queue_depth)
		reg->queue_depth = BLK_MQ_MAX_DEPTH;
	else if (reg->queue_depth > BLK_MQ_MAX_DEPTH) {
		pr_err("blk-mq: queuedepth too large (%u)\n", reg->queue_depth);
		reg->queue_depth = BLK_MQ_MAX_DEPTH;
	}

	if (reg->queue_depth < (reg->reserved_tags + BLK_MQ_TAG_MIN))
		return ERR_PTR(-EINVAL);

	ctx = alloc_percpu(struct blk_mq_ctx);
	if (!ctx)
		return ERR_PTR(-ENOMEM);

	hctxs = kmalloc_node(reg->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL,
			reg->numa_node);

	if (!hctxs)
		goto err_percpu;

	for (i = 0; i < reg->nr_hw_queues; i++) {
		hctxs[i] = reg->ops->alloc_hctx(reg, i);
		if (!hctxs[i])
			goto err_hctxs;

1331 1332 1333
		if (!zalloc_cpumask_var(&hctxs[i]->cpumask, GFP_KERNEL))
			goto err_hctxs;

1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355
		hctxs[i]->numa_node = NUMA_NO_NODE;
		hctxs[i]->queue_num = i;
	}

	q = blk_alloc_queue_node(GFP_KERNEL, reg->numa_node);
	if (!q)
		goto err_hctxs;

	q->mq_map = blk_mq_make_queue_map(reg);
	if (!q->mq_map)
		goto err_map;

	setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
	blk_queue_rq_timeout(q, 30000);

	q->nr_queues = nr_cpu_ids;
	q->nr_hw_queues = reg->nr_hw_queues;

	q->queue_ctx = ctx;
	q->queue_hw_ctx = hctxs;

	q->mq_ops = reg->ops;
1356
	q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
1357

1358 1359
	q->sg_reserved_size = INT_MAX;

1360 1361 1362 1363 1364
	blk_queue_make_request(q, blk_mq_make_request);
	blk_queue_rq_timed_out(q, reg->ops->timeout);
	if (reg->timeout)
		blk_queue_rq_timeout(q, reg->timeout);

1365 1366 1367
	if (reg->ops->complete)
		blk_queue_softirq_done(q, reg->ops->complete);

1368 1369 1370
	blk_mq_init_flush(q);
	blk_mq_init_cpu_queues(q, reg->nr_hw_queues);

1371 1372 1373
	q->flush_rq = kzalloc(round_up(sizeof(struct request) + reg->cmd_size,
				cache_line_size()), GFP_KERNEL);
	if (!q->flush_rq)
1374 1375
		goto err_hw;

1376 1377 1378
	if (blk_mq_init_hw_queues(q, reg, driver_data))
		goto err_flush_rq;

1379 1380 1381 1382 1383 1384 1385
	blk_mq_map_swqueue(q);

	mutex_lock(&all_q_mutex);
	list_add_tail(&q->all_q_node, &all_q_list);
	mutex_unlock(&all_q_mutex);

	return q;
1386 1387 1388

err_flush_rq:
	kfree(q->flush_rq);
1389 1390 1391 1392 1393 1394 1395 1396
err_hw:
	kfree(q->mq_map);
err_map:
	blk_cleanup_queue(q);
err_hctxs:
	for (i = 0; i < reg->nr_hw_queues; i++) {
		if (!hctxs[i])
			break;
1397
		free_cpumask_var(hctxs[i]->cpumask);
1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414
		reg->ops->free_hctx(hctxs[i], i);
	}
	kfree(hctxs);
err_percpu:
	free_percpu(ctx);
	return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(blk_mq_init_queue);

void blk_mq_free_queue(struct request_queue *q)
{
	struct blk_mq_hw_ctx *hctx;
	int i;

	queue_for_each_hw_ctx(q, hctx, i) {
		kfree(hctx->ctx_map);
		kfree(hctx->ctxs);
1415
		blk_mq_free_rq_map(hctx, q->queuedata);
1416 1417 1418
		blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
		if (q->mq_ops->exit_hctx)
			q->mq_ops->exit_hctx(hctx, i);
1419
		free_cpumask_var(hctx->cpumask);
1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
		q->mq_ops->free_hctx(hctx, i);
	}

	free_percpu(q->queue_ctx);
	kfree(q->queue_hw_ctx);
	kfree(q->mq_map);

	q->queue_ctx = NULL;
	q->queue_hw_ctx = NULL;
	q->mq_map = NULL;

	mutex_lock(&all_q_mutex);
	list_del_init(&q->all_q_node);
	mutex_unlock(&all_q_mutex);
}

/* Basically redo blk_mq_init_queue with queue frozen */
1437
static void blk_mq_queue_reinit(struct request_queue *q)
1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453
{
	blk_mq_freeze_queue(q);

	blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues);

	/*
	 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
	 * we should change hctx numa_node according to new topology (this
	 * involves free and re-allocate memory, worthy doing?)
	 */

	blk_mq_map_swqueue(q);

	blk_mq_unfreeze_queue(q);
}

1454 1455
static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
				      unsigned long action, void *hcpu)
1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475
{
	struct request_queue *q;

	/*
	 * Before new mapping is established, hotadded cpu might already start
	 * handling requests. This doesn't break anything as we map offline
	 * CPUs to first hardware queue. We will re-init queue below to get
	 * optimal settings.
	 */
	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN &&
	    action != CPU_ONLINE && action != CPU_ONLINE_FROZEN)
		return NOTIFY_OK;

	mutex_lock(&all_q_mutex);
	list_for_each_entry(q, &all_q_list, all_q_node)
		blk_mq_queue_reinit(q);
	mutex_unlock(&all_q_mutex);
	return NOTIFY_OK;
}

1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
void blk_mq_disable_hotplug(void)
{
	mutex_lock(&all_q_mutex);
}

void blk_mq_enable_hotplug(void)
{
	mutex_unlock(&all_q_mutex);
}

1486 1487 1488 1489 1490 1491 1492 1493 1494 1495
static int __init blk_mq_init(void)
{
	blk_mq_cpu_init();

	/* Must be called after percpu_counter_hotcpu_callback() */
	hotcpu_notifier(blk_mq_queue_reinit_notify, -10);

	return 0;
}
subsys_initcall(blk_mq_init);