#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);
  }

  static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
  					      gfp_t gfp, bool reserved)

  {
  	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];
  		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,

  		!blk_queue_bypass(q) || blk_queue_dying(q),
  		*q->queue_lock);

  	/* inc usage with lock hold to avoid freeze_queue runs here */

  	if (!ret && !blk_queue_dying(q))

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

  	else if (blk_queue_dying(q))
  		ret = -ENODEV;

  	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);
  }

  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);
  	}
  }

  /*
   * 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);

  	if (drain)
  		__blk_mq_drain_queue(q);
  }

  void blk_mq_drain_queue(struct request_queue *q)
  {
  	__blk_mq_drain_queue(q);

  }
  
  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);

  static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
  			       struct request *rq, unsigned int rw_flags)

  {

  	if (blk_queue_io_stat(q))
  		rw_flags |= REQ_IO_STAT;

  	rq->mq_ctx = ctx;
  	rq->cmd_flags = rw_flags;

  	rq->start_time = jiffies;
  	set_start_time_ns(rq);

  	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);

  		rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved);

  		if (rq) {

  			blk_mq_rq_ctx_init(q, ctx, rq, rw);

  			break;

  		}

  
  		blk_mq_put_ctx(ctx);

  		if (!(gfp & __GFP_WAIT))
  			break;

  		__blk_mq_run_hw_queue(hctx);
  		blk_mq_wait_for_tags(hctx->tags);
  	} while (1);
  
  	return rq;
  }

  struct request *blk_mq_alloc_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, false);

  	if (rq)
  		blk_mq_put_ctx(rq->mq_ctx);

  	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);

  	if (rq)
  		blk_mq_put_ctx(rq->mq_ctx);

  	return rq;
  }
  EXPORT_SYMBOL(blk_mq_alloc_reserved_request);
  
  /*
   * Re-init and set pdu, if we have it
   */

  void blk_mq_rq_init(struct blk_mq_hw_ctx *hctx, struct request *rq)

  {
  	blk_rq_init(hctx->queue, rq);
  
  	if (hctx->cmd_size)
  		rq->special = blk_mq_rq_to_pdu(rq);
  }
  
  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_rq_init(hctx, rq);
  	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);
  }

  bool blk_mq_end_io_partial(struct request *rq, int error, unsigned int nr_bytes)

  {

  	if (blk_update_request(rq, error, blk_rq_bytes(rq)))
  		return true;

  	blk_account_io_done(rq);

  	if (rq->end_io)
  		rq->end_io(rq, error);
  	else
  		blk_mq_free_request(rq);

  	return false;

  }

  EXPORT_SYMBOL(blk_mq_end_io_partial);

  static void __blk_mq_complete_request_remote(void *data)

  {

  	struct request *rq = data;

  	rq->q->softirq_done_fn(rq);

  }

  void __blk_mq_complete_request(struct request *rq)

  {
  	struct blk_mq_ctx *ctx = rq->mq_ctx;
  	int cpu;

  	if (!ctx->ipi_redirect) {
  		rq->q->softirq_done_fn(rq);
  		return;
  	}

  
  	cpu = get_cpu();

  	if (cpu != ctx->cpu && cpu_online(ctx->cpu)) {

  		rq->csd.func = __blk_mq_complete_request_remote;

  		rq->csd.info = rq;
  		rq->csd.flags = 0;

  		smp_call_function_single_async(ctx->cpu, &rq->csd);

  	} else {

  		rq->q->softirq_done_fn(rq);

  	}

  	put_cpu();
  }

  
  /**
   * 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);

  static void blk_mq_start_request(struct request *rq, bool last)

  {
  	struct request_queue *q = rq->q;
  
  	trace_block_rq_issue(q, rq);
  
  	/*
  	 * 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);

  
  	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;

  }
  
  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);

  
  	rq->cmd_flags &= ~REQ_END;
  
  	if (q->dma_drain_size && blk_rq_bytes(rq))
  		rq->nr_phys_segments--;

  }
  
  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;

  	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))

  		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);

  		blk_mq_start_request(rq, list_empty(&rq_list));

  
  		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
  ", ret);

  		case BLK_MQ_RQ_QUEUE_ERROR:

  			rq->errors = -EIO;

  			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)
  {

  	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))

  		return;
  
  	if (!async)
  		__blk_mq_run_hw_queue(hctx);
  	else {
  		struct request_queue *q = hctx->queue;
  
  		kblockd_schedule_delayed_work(q, &hctx->delayed_work, 0);
  	}
  }
  
  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)) ||

  		    test_bit(BLK_MQ_S_STOPPED, &hctx->state))

  			continue;
  
  		blk_mq_run_hw_queue(hctx, async);
  	}
  }
  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);

  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);

  void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
  {
  	clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
  	__blk_mq_run_hw_queue(hctx);
  }
  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);
  		blk_mq_run_hw_queue(hctx, true);
  	}
  }
  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);
  	__blk_mq_run_hw_queue(hctx);
  }
  
  static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,

  				    struct request *rq, bool at_head)

  {
  	struct blk_mq_ctx *ctx = rq->mq_ctx;

  	trace_block_rq_insert(hctx->queue, rq);

  	if (at_head)
  		list_add(&rq->queuelist, &ctx->rq_list);
  	else
  		list_add_tail(&rq->queuelist, &ctx->rq_list);

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

  void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
  		bool async)

  {

  	struct request_queue *q = rq->q;

  	struct blk_mq_hw_ctx *hctx;

  	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;

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

  	if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA) &&
  	    !(rq->cmd_flags & (REQ_FLUSH_SEQ))) {

  		blk_insert_flush(rq);
  	} else {

  		spin_lock(&ctx->lock);

  		__blk_mq_insert_request(hctx, rq, at_head);

  		spin_unlock(&ctx->lock);

  	}

  	blk_mq_put_ctx(current_ctx);
  
  	if (run_queue)
  		blk_mq_run_hw_queue(hctx, async);
  }
  
  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;

  		__blk_mq_insert_request(hctx, rq, false);

  	}
  	spin_unlock(&ctx->lock);
  
  	blk_mq_put_ctx(current_ctx);
  
  	blk_mq_run_hw_queue(hctx, from_schedule);
  }
  
  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);

  	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
  		bio_endio(bio, -EIO);
  		return;
  	}

  	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);

  	if (is_sync)
  		rw |= REQ_SYNC;

  	trace_block_getrq(q, bio, rw);

  	rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false);

  	if (likely(rq))

  		blk_mq_rq_ctx_init(q, ctx, rq, rw);

  	else {
  		blk_mq_put_ctx(ctx);
  		trace_block_sleeprq(q, bio, rw);

  		rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC,
  							false);

  		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_mq_put_ctx(ctx);
  		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);

  			if (list_empty(&plug->mq_list))

  				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);

  		__blk_mq_insert_request(hctx, rq, false);

  	}
  
  	spin_unlock(&ctx->lock);
  	blk_mq_put_ctx(ctx);
  
  	/*
  	 * 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);
  }
  
  /*
   * 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;

  	struct request_queue *q = hctx->queue;

  	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.
  	 */

  	ctx = __blk_mq_get_ctx(q, cpu);

  
  	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;

  	ctx = blk_mq_get_ctx(q);

  	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);
  	}

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

  	blk_mq_hctx_mark_pending(hctx, ctx);
  
  	spin_unlock(&ctx->lock);
  	blk_mq_put_ctx(ctx);

  
  	blk_mq_run_hw_queue(hctx, true);

  }

  static int blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
  				   int (*init)(void *, struct blk_mq_hw_ctx *,
  					struct request *, unsigned int),
  				   void *data)
  {
  	unsigned int i;
  	int ret = 0;
  
  	for (i = 0; i < hctx->queue_depth; i++) {
  		struct request *rq = hctx->rqs[i];
  
  		ret = init(data, hctx, rq, i);
  		if (ret)
  			break;
  	}
  
  	return ret;
  }
  
  int blk_mq_init_commands(struct request_queue *q,
  			 int (*init)(void *, struct blk_mq_hw_ctx *,
  					struct request *, unsigned int),
  			 void *data)
  {
  	struct blk_mq_hw_ctx *hctx;
  	unsigned int i;
  	int ret = 0;
  
  	queue_for_each_hw_ctx(q, hctx, i) {
  		ret = blk_mq_init_hw_commands(hctx, init, data);
  		if (ret)
  			break;
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL(blk_mq_init_commands);
  
  static void blk_mq_free_hw_commands(struct blk_mq_hw_ctx *hctx,
  				    void (*free)(void *, struct blk_mq_hw_ctx *,

  					struct request *, unsigned int),
  				    void *data)
  {
  	unsigned int i;
  
  	for (i = 0; i < hctx->queue_depth; i++) {
  		struct request *rq = hctx->rqs[i];

  		free(data, hctx, rq, i);

  	}
  }

  void blk_mq_free_commands(struct request_queue *q,
  			  void (*free)(void *, struct blk_mq_hw_ctx *,

  					struct request *, unsigned int),
  			  void *data)
  {
  	struct blk_mq_hw_ctx *hctx;
  	unsigned int i;
  
  	queue_for_each_hw_ctx(q, hctx, i)

  		blk_mq_free_hw_commands(hctx, free, data);

  }

  EXPORT_SYMBOL(blk_mq_free_commands);

  
  static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
  {
  	struct page *page;
  
  	while (!list_empty(&hctx->page_list)) {

  		page = list_first_entry(&hctx->page_list, struct page, lru);
  		list_del_init(&page->lru);

  		__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,
  			      unsigned int reserved_tags, int node)
  {
  	unsigned int i, j, entries_per_page, max_order = 4;
  	size_t rq_size, left;
  
  	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;

  		list_add_tail(&page->lru, &hctx->page_list);

  
  		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;
  			blk_mq_rq_init(hctx, hctx->rqs[i]);
  			p += rq_size;
  			i++;
  		}
  	}
  
  	if (i < (reserved_tags + BLK_MQ_TAG_MIN))
  		goto err_rq_map;
  	else if (i != hctx->queue_depth) {
  		hctx->queue_depth = i;
  		pr_warn("%s: queue depth set to %u because of low memory
  ",
  					__func__, i);
  	}
  
  	hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
  	if (!hctx->tags) {
  err_rq_map:
  		blk_mq_free_rq_map(hctx);
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  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);
  
  		if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node))
  			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);
  		blk_mq_free_rq_map(hctx);
  		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 */
  		hctx = q->mq_ops->map_queue(q, i);
  		hctx->nr_ctx++;
  
  		if (!cpu_online(i))
  			continue;
  
  		/*
  		 * 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) {
  		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 */
  		hctx = q->mq_ops->map_queue(q, i);
  		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)
  ", 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;
  
  		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;

  	q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;

  	q->sg_reserved_size = INT_MAX;

  	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);

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

  	blk_mq_init_flush(q);
  	blk_mq_init_cpu_queues(q, reg->nr_hw_queues);

  	q->flush_rq = kzalloc(round_up(sizeof(struct request) + reg->cmd_size,
  				cache_line_size()), GFP_KERNEL);
  	if (!q->flush_rq)

  		goto err_hw;

  	if (blk_mq_init_hw_queues(q, reg, driver_data))
  		goto err_flush_rq;

  	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;

  
  err_flush_rq:
  	kfree(q->flush_rq);

  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;
  		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);
  		blk_mq_free_rq_map(hctx);
  		blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
  		if (q->mq_ops->exit_hctx)
  			q->mq_ops->exit_hctx(hctx, i);
  		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 */

  static void blk_mq_queue_reinit(struct request_queue *q)

  {
  	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);
  }

  static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
  				      unsigned long action, void *hcpu)

  {
  	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;
  }

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

  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);