fixup! kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS
Dan Willemsen [Wed, 14 May 2014 18:47:13 +0000 (11:47 -0700)]
This file was added as a result of bad conflict resolution in this
backport. Remove it, as it isn't used.

Signed-off-by: Dan Willemsen <dwillemsen@nvidia.com>
Change-Id: Ide9fc67ca714d62a2fbec47d67922879bf3fa3f4
Reviewed-on: http://git-master/r/409755
Reviewed-by: Ishan Mittal <imittal@nvidia.com>
Tested-by: Ishan Mittal <imittal@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

block/blk-mq.c [deleted file]

diff --git a/block/blk-mq.c b/block/blk-mq.c
deleted file mode 100644 (file)
index c661896..0000000
+++ /dev/null
@@ -1,1500 +0,0 @@
-#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);
-
-DEFINE_PER_CPU(struct llist_head, ipi_lists);
-
-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_rq(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), *q->queue_lock);
-       /* inc usage with lock hold to avoid freeze_queue runs here */
-       if (!ret)
-               __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
-       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);
-}
-
-/*
- * 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)
-               return;
-
-       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);
-       }
-}
-
-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 blk_mq_ctx *ctx, struct request *rq,
-                              unsigned int rw_flags)
-{
-       rq->mq_ctx = ctx;
-       rq->cmd_flags = rw_flags;
-       ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
-}
-
-static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
-                                             gfp_t gfp, bool reserved)
-{
-       return blk_mq_alloc_rq(hctx, gfp, reserved);
-}
-
-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(ctx, rq, rw);
-                       break;
-               } else if (!(gfp & __GFP_WAIT))
-                       break;
-
-               blk_mq_put_ctx(ctx);
-               __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, bool reserved)
-{
-       struct request *rq;
-
-       if (blk_mq_queue_enter(q))
-               return NULL;
-
-       rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved);
-       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);
-       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
- */
-static 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);
-}
-
-static void blk_mq_bio_endio(struct request *rq, struct bio *bio, int error)
-{
-       if (error)
-               clear_bit(BIO_UPTODATE, &bio->bi_flags);
-       else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
-               error = -EIO;
-
-       if (unlikely(rq->cmd_flags & REQ_QUIET))
-               set_bit(BIO_QUIET, &bio->bi_flags);
-
-       /* don't actually finish bio if it's part of flush sequence */
-       if (!(rq->cmd_flags & REQ_FLUSH_SEQ))
-               bio_endio(bio, error);
-}
-
-void blk_mq_complete_request(struct request *rq, int error)
-{
-       struct bio *bio = rq->bio;
-       unsigned int bytes = 0;
-
-       trace_block_rq_complete(rq->q, rq);
-
-       while (bio) {
-               struct bio *next = bio->bi_next;
-
-               bio->bi_next = NULL;
-               bytes += bio->bi_size;
-               blk_mq_bio_endio(rq, bio, error);
-               bio = next;
-       }
-
-       blk_account_io_completion(rq, bytes);
-
-       if (rq->end_io)
-               rq->end_io(rq, error);
-       else
-               blk_mq_free_request(rq);
-
-       blk_account_io_done(rq);
-}
-
-void __blk_mq_end_io(struct request *rq, int error)
-{
-       if (!blk_mark_rq_complete(rq))
-               blk_mq_complete_request(rq, error);
-}
-
-#if defined(CONFIG_SMP)
-
-/*
- * Called with interrupts disabled.
- */
-static void ipi_end_io(void *data)
-{
-       struct llist_head *list = &per_cpu(ipi_lists, smp_processor_id());
-       struct llist_node *entry, *next;
-       struct request *rq;
-
-       entry = llist_del_all(list);
-
-       while (entry) {
-               next = entry->next;
-               rq = llist_entry(entry, struct request, ll_list);
-               __blk_mq_end_io(rq, rq->errors);
-               entry = next;
-       }
-}
-
-static int ipi_remote_cpu(struct blk_mq_ctx *ctx, const int cpu,
-                         struct request *rq, const int error)
-{
-       struct call_single_data *data = &rq->csd;
-
-       rq->errors = error;
-       rq->ll_list.next = NULL;
-
-       /*
-        * If the list is non-empty, an existing IPI must already
-        * be "in flight". If that is the case, we need not schedule
-        * a new one.
-        */
-       if (llist_add(&rq->ll_list, &per_cpu(ipi_lists, ctx->cpu))) {
-               data->func = ipi_end_io;
-               data->flags = 0;
-               __smp_call_function_single(ctx->cpu, data, 0);
-       }
-
-       return true;
-}
-#else /* CONFIG_SMP */
-static int ipi_remote_cpu(struct blk_mq_ctx *ctx, const int cpu,
-                         struct request *rq, const int error)
-{
-       return false;
-}
-#endif
-
-/*
- * End IO on this request on a multiqueue enabled driver. We'll either do
- * it directly inline, or punt to a local IPI handler on the matching
- * remote CPU.
- */
-void blk_mq_end_io(struct request *rq, int error)
-{
-       struct blk_mq_ctx *ctx = rq->mq_ctx;
-       int cpu;
-
-       if (!ctx->ipi_redirect)
-               return __blk_mq_end_io(rq, error);
-
-       cpu = get_cpu();
-
-       if (cpu == ctx->cpu || !cpu_online(ctx->cpu) ||
-           !ipi_remote_cpu(ctx, cpu, rq, error))
-               __blk_mq_end_io(rq, error);
-
-       put_cpu();
-}
-EXPORT_SYMBOL(blk_mq_end_io);
-
-static void blk_mq_start_request(struct request *rq)
-{
-       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);
-}
-
-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);
-}
-
-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->flags)))
-               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);
-
-               /*
-                * Last request in the series. Flag it as such, this
-                * enables drivers to 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 (list_empty(&rq_list))
-                       rq->cmd_flags |= REQ_END;
-
-               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);
-                       rq->errors = -EIO;
-               case BLK_MQ_RQ_QUEUE_ERROR:
-                       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->flags)))
-               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->flags))
-                       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)
-{
-       struct blk_mq_ctx *ctx = rq->mq_ctx;
-
-       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_queue *q, struct request *rq,
-                          bool run_queue)
-{
-       struct blk_mq_hw_ctx *hctx;
-       struct blk_mq_ctx *ctx, *current_ctx;
-
-       ctx = rq->mq_ctx;
-       hctx = q->mq_ops->map_queue(q, ctx->cpu);
-
-       if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
-               blk_insert_flush(rq);
-       } else {
-               current_ctx = blk_mq_get_ctx(q);
-
-               if (!cpu_online(ctx->cpu)) {
-                       ctx = current_ctx;
-                       hctx = q->mq_ops->map_queue(q, ctx->cpu);
-                       rq->mq_ctx = ctx;
-               }
-               spin_lock(&ctx->lock);
-               __blk_mq_insert_request(hctx, rq);
-               spin_unlock(&ctx->lock);
-
-               blk_mq_put_ctx(current_ctx);
-       }
-
-       if (run_queue)
-               __blk_mq_run_hw_queue(hctx);
-}
-EXPORT_SYMBOL(blk_mq_insert_request);
-
-/*
- * This is a special version of blk_mq_insert_request to bypass FLUSH request
- * check. Should only be used internally.
- */
-void blk_mq_run_request(struct request *rq, bool run_queue, bool async)
-{
-       struct request_queue *q = rq->q;
-       struct blk_mq_hw_ctx *hctx;
-       struct blk_mq_ctx *ctx, *current_ctx;
-
-       current_ctx = blk_mq_get_ctx(q);
-
-       ctx = rq->mq_ctx;
-       if (!cpu_online(ctx->cpu)) {
-               ctx = current_ctx;
-               rq->mq_ctx = ctx;
-       }
-       hctx = q->mq_ops->map_queue(q, ctx->cpu);
-
-       /* ctx->cpu might be offline */
-       spin_lock(&ctx->lock);
-       __blk_mq_insert_request(hctx, rq);
-       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);
-       }
-       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 (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);
-
-       trace_block_getrq(q, bio, rw);
-       rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false);
-       if (likely(rq))
-               blk_mq_rq_ctx_init(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);
-       }
-
-       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 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(hctx->queue, 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(hctx->queue);
-       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);
-       }
-
-       blk_mq_hctx_mark_pending(hctx, ctx);
-
-       spin_unlock(&ctx->lock);
-       blk_mq_put_ctx(ctx);
-}
-
-static void blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
-                                   void (*init)(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];
-
-               init(data, hctx, rq, i);
-       }
-}
-
-void blk_mq_init_commands(struct request_queue *q,
-                         void (*init)(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_init_hw_commands(hctx, init, data);
-}
-EXPORT_SYMBOL(blk_mq_init_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, list);
-               list_del_init(&page->list);
-               __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->list, &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\n",
-                                       __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)\n", reg->queue_depth);
-               reg->queue_depth = BLK_MQ_MAX_DEPTH;
-       }
-
-       /*
-        * Set aside a tag for flush requests.  It will only be used while
-        * another flush request is in progress but outside the driver.
-        *
-        * TODO: only allocate if flushes are supported
-        */
-       reg->queue_depth++;
-       reg->reserved_tags++;
-
-       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;
-
-       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);
-
-       blk_mq_init_flush(q);
-       blk_mq_init_cpu_queues(q, reg->nr_hw_queues);
-
-       if (blk_mq_init_hw_queues(q, reg, driver_data))
-               goto err_hw;
-
-       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_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) {
-               cancel_delayed_work_sync(&hctx->delayed_work);
-               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);
-}
-EXPORT_SYMBOL(blk_mq_free_queue);
-
-/* Basically redo blk_mq_init_queue with queue frozen */
-static void __cpuinit 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 __cpuinit 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;
-}
-
-static int __init blk_mq_init(void)
-{
-       unsigned int i;
-
-       for_each_possible_cpu(i)
-               init_llist_head(&per_cpu(ipi_lists, i));
-
-       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);