block: remove legacy IO schedulers

Retain the deadline documentation, as that carries over to mq-deadline
as well.

Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

7 files changed, 0 insertions, 6025 deletions

diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt
deleted file mode 100644
index 895bd3813115..000000000000
--- a/Documentation/block/cfq-iosched.txt
+++ /dev/null
@@ -1,291 +0,0 @@
-CFQ (Complete Fairness Queueing)
-===============================
-
-The main aim of CFQ scheduler is to provide a fair allocation of the disk
-I/O bandwidth for all the processes which requests an I/O operation.
-
-CFQ maintains the per process queue for the processes which request I/O
-operation(synchronous requests). In case of asynchronous requests, all the
-requests from all the processes are batched together according to their
-process's I/O priority.
-
-CFQ ioscheduler tunables
-========================
-
-slice_idle
-----------
-This specifies how long CFQ should idle for next request on certain cfq queues
-(for sequential workloads) and service trees (for random workloads) before
-queue is expired and CFQ selects next queue to dispatch from.
-
-By default slice_idle is a non-zero value. That means by default we idle on
-queues/service trees. This can be very helpful on highly seeky media like
-single spindle SATA/SAS disks where we can cut down on overall number of
-seeks and see improved throughput.
-
-Setting slice_idle to 0 will remove all the idling on queues/service tree
-level and one should see an overall improved throughput on faster storage
-devices like multiple SATA/SAS disks in hardware RAID configuration. The down
-side is that isolation provided from WRITES also goes down and notion of
-IO priority becomes weaker.
-
-So depending on storage and workload, it might be useful to set slice_idle=0.
-In general I think for SATA/SAS disks and software RAID of SATA/SAS disks
-keeping slice_idle enabled should be useful. For any configurations where
-there are multiple spindles behind single LUN (Host based hardware RAID
-controller or for storage arrays), setting slice_idle=0 might end up in better
-throughput and acceptable latencies.
-
-back_seek_max
--------------
-This specifies, given in Kbytes, the maximum "distance" for backward seeking.
-The distance is the amount of space from the current head location to the
-sectors that are backward in terms of distance.
-
-This parameter allows the scheduler to anticipate requests in the "backward"
-direction and consider them as being the "next" if they are within this
-distance from the current head location.
-
-back_seek_penalty
------------------
-This parameter is used to compute the cost of backward seeking. If the
-backward distance of request is just 1/back_seek_penalty from a "front"
-request, then the seeking cost of two requests is considered equivalent.
-
-So scheduler will not bias toward one or the other request (otherwise scheduler
-will bias toward front request). Default value of back_seek_penalty is 2.
-
-fifo_expire_async
------------------
-This parameter is used to set the timeout of asynchronous requests. Default
-value of this is 248ms.
-
-fifo_expire_sync
-----------------
-This parameter is used to set the timeout of synchronous requests. Default
-value of this is 124ms. In case to favor synchronous requests over asynchronous
-one, this value should be decreased relative to fifo_expire_async.
-
-group_idle
------------
-This parameter forces idling at the CFQ group level instead of CFQ
-queue level. This was introduced after a bottleneck was observed
-in higher end storage due to idle on sequential queue and allow dispatch
-from a single queue. The idea with this parameter is that it can be run with
-slice_idle=0 and group_idle=8, so that idling does not happen on individual
-queues in the group but happens overall on the group and thus still keeps the
-IO controller working.
-Not idling on individual queues in the group will dispatch requests from
-multiple queues in the group at the same time and achieve higher throughput
-on higher end storage.
-
-Default value for this parameter is 8ms.
-
-low_latency
------------
-This parameter is used to enable/disable the low latency mode of the CFQ
-scheduler. If enabled, CFQ tries to recompute the slice time for each process
-based on the target_latency set for the system. This favors fairness over
-throughput. Disabling low latency (setting it to 0) ignores target latency,
-allowing each process in the system to get a full time slice.
-
-By default low latency mode is enabled.
-
-target_latency
---------------
-This parameter is used to calculate the time slice for a process if cfq's
-latency mode is enabled. It will ensure that sync requests have an estimated
-latency. But if sequential workload is higher(e.g. sequential read),
-then to meet the latency constraints, throughput may decrease because of less
-time for each process to issue I/O request before the cfq queue is switched.
-
-Though this can be overcome by disabling the latency_mode, it may increase
-the read latency for some applications. This parameter allows for changing
-target_latency through the sysfs interface which can provide the balanced
-throughput and read latency.
-
-Default value for target_latency is 300ms.
-
-slice_async
------------
-This parameter is same as of slice_sync but for asynchronous queue. The
-default value is 40ms.
-
-slice_async_rq
---------------
-This parameter is used to limit the dispatching of asynchronous request to
-device request queue in queue's slice time. The maximum number of request that
-are allowed to be dispatched also depends upon the io priority. Default value
-for this is 2.
-
-slice_sync
-----------
-When a queue is selected for execution, the queues IO requests are only
-executed for a certain amount of time(time_slice) before switching to another
-queue. This parameter is used to calculate the time slice of synchronous
-queue.
-
-time_slice is computed using the below equation:-
-time_slice = slice_sync + (slice_sync/5 * (4 - prio)). To increase the
-time_slice of synchronous queue, increase the value of slice_sync. Default
-value is 100ms.
-
-quantum
--------
-This specifies the number of request dispatched to the device queue. In a
-queue's time slice, a request will not be dispatched if the number of request
-in the device exceeds this parameter. This parameter is used for synchronous
-request.
-
-In case of storage with several disk, this setting can limit the parallel
-processing of request. Therefore, increasing the value can improve the
-performance although this can cause the latency of some I/O to increase due
-to more number of requests.
-
-CFQ Group scheduling
-====================
-
-CFQ supports blkio cgroup and has "blkio." prefixed files in each
-blkio cgroup directory. It is weight-based and there are four knobs
-for configuration - weight[_device] and leaf_weight[_device].
-Internal cgroup nodes (the ones with children) can also have tasks in
-them, so the former two configure how much proportion the cgroup as a
-whole is entitled to at its parent's level while the latter two
-configure how much proportion the tasks in the cgroup have compared to
-its direct children.
-
-Another way to think about it is assuming that each internal node has
-an implicit leaf child node which hosts all the tasks whose weight is
-configured by leaf_weight[_device]. Let's assume a blkio hierarchy
-composed of five cgroups - root, A, B, AA and AB - with the following
-weights where the names represent the hierarchy.
-
-        weight leaf_weight
- root :  125    125
- A    :  500    750
- B    :  250    500
- AA   :  500    500
- AB   : 1000    500
-
-root never has a parent making its weight is meaningless. For backward
-compatibility, weight is always kept in sync with leaf_weight. B, AA
-and AB have no child and thus its tasks have no children cgroup to
-compete with. They always get 100% of what the cgroup won at the
-parent level. Considering only the weights which matter, the hierarchy
-looks like the following.
-
-          root
-       /    |   \
-      A     B    leaf
-     500   250   125
-   /  |  \
-  AA  AB  leaf
- 500 1000 750
-
-If all cgroups have active IOs and competing with each other, disk
-time will be distributed like the following.
-
-Distribution below root. The total active weight at this level is
-A:500 + B:250 + C:125 = 875.
-
- root-leaf :   125 /  875      =~ 14%
- A         :   500 /  875      =~ 57%
- B(-leaf)  :   250 /  875      =~ 28%
-
-A has children and further distributes its 57% among the children and
-the implicit leaf node. The total active weight at this level is
-AA:500 + AB:1000 + A-leaf:750 = 2250.
-
- A-leaf    : ( 750 / 2250) * A =~ 19%
- AA(-leaf) : ( 500 / 2250) * A =~ 12%
- AB(-leaf) : (1000 / 2250) * A =~ 25%
-
-CFQ IOPS Mode for group scheduling
-===================================
-Basic CFQ design is to provide priority based time slices. Higher priority
-process gets bigger time slice and lower priority process gets smaller time
-slice. Measuring time becomes harder if storage is fast and supports NCQ and
-it would be better to dispatch multiple requests from multiple cfq queues in
-request queue at a time. In such scenario, it is not possible to measure time
-consumed by single queue accurately.
-
-What is possible though is to measure number of requests dispatched from a
-single queue and also allow dispatch from multiple cfq queue at the same time.
-This effectively becomes the fairness in terms of IOPS (IO operations per
-second).
-
-If one sets slice_idle=0 and if storage supports NCQ, CFQ internally switches
-to IOPS mode and starts providing fairness in terms of number of requests
-dispatched. Note that this mode switching takes effect only for group
-scheduling. For non-cgroup users nothing should change.
-
-CFQ IO scheduler Idling Theory
-===============================
-Idling on a queue is primarily about waiting for the next request to come
-on same queue after completion of a request. In this process CFQ will not
-dispatch requests from other cfq queues even if requests are pending there.
-
-The rationale behind idling is that it can cut down on number of seeks
-on rotational media. For example, if a process is doing dependent
-sequential reads (next read will come on only after completion of previous
-one), then not dispatching request from other queue should help as we
-did not move the disk head and kept on dispatching sequential IO from
-one queue.
-
-CFQ has following service trees and various queues are put on these trees.
-
-	sync-idle	sync-noidle	async
-
-All cfq queues doing synchronous sequential IO go on to sync-idle tree.
-On this tree we idle on each queue individually.
-
-All synchronous non-sequential queues go on sync-noidle tree. Also any
-synchronous write request which is not marked with REQ_IDLE goes on this
-service tree. On this tree we do not idle on individual queues instead idle
-on the whole group of queues or the tree. So if there are 4 queues waiting
-for IO to dispatch we will idle only once last queue has dispatched the IO
-and there is no more IO on this service tree.
-
-All async writes go on async service tree. There is no idling on async
-queues.
-
-CFQ has some optimizations for SSDs and if it detects a non-rotational
-media which can support higher queue depth (multiple requests at in
-flight at a time), then it cuts down on idling of individual queues and
-all the queues move to sync-noidle tree and only tree idle remains. This
-tree idling provides isolation with buffered write queues on async tree.
-
-FAQ
-===
-Q1. Why to idle at all on queues not marked with REQ_IDLE.
-
-A1. We only do tree idle (all queues on sync-noidle tree) on queues not marked
-    with REQ_IDLE. This helps in providing isolation with all the sync-idle
-    queues. Otherwise in presence of many sequential readers, other
-    synchronous IO might not get fair share of disk.
-
-    For example, if there are 10 sequential readers doing IO and they get
-    100ms each. If a !REQ_IDLE request comes in, it will be scheduled
-    roughly after 1 second. If after completion of !REQ_IDLE request we
-    do not idle, and after a couple of milli seconds a another !REQ_IDLE
-    request comes in, again it will be scheduled after 1second. Repeat it
-    and notice how a workload can lose its disk share and suffer due to
-    multiple sequential readers.
-
-    fsync can generate dependent IO where bunch of data is written in the
-    context of fsync, and later some journaling data is written. Journaling
-    data comes in only after fsync has finished its IO (atleast for ext4
-    that seemed to be the case). Now if one decides not to idle on fsync
-    thread due to !REQ_IDLE, then next journaling write will not get
-    scheduled for another second. A process doing small fsync, will suffer
-    badly in presence of multiple sequential readers.
-
-    Hence doing tree idling on threads using !REQ_IDLE flag on requests
-    provides isolation from multiple sequential readers and at the same
-    time we do not idle on individual threads.
-
-Q2. When to specify REQ_IDLE
-A2. I would think whenever one is doing synchronous write and expecting
-    more writes to be dispatched from same context soon, should be able
-    to specify REQ_IDLE on writes and that probably should work well for
-    most of the cases.
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index f95a48b0d7b2..4626b88b2d5a 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -3,67 +3,6 @@ if BLOCK
 
 menu "IO Schedulers"
 
-config IOSCHED_NOOP
-	bool
-	default y
-	---help---
-	  The no-op I/O scheduler is a minimal scheduler that does basic merging
-	  and sorting. Its main uses include non-disk based block devices like
-	  memory devices, and specialised software or hardware environments
-	  that do their own scheduling and require only minimal assistance from
-	  the kernel.
-
-config IOSCHED_DEADLINE
-	tristate "Deadline I/O scheduler"
-	default y
-	---help---
-	  The deadline I/O scheduler is simple and compact. It will provide
-	  CSCAN service with FIFO expiration of requests, switching to
-	  a new point in the service tree and doing a batch of IO from there
-	  in case of expiry.
-
-config IOSCHED_CFQ
-	tristate "CFQ I/O scheduler"
-	default y
-	---help---
-	  The CFQ I/O scheduler tries to distribute bandwidth equally
-	  among all processes in the system. It should provide a fair
-	  and low latency working environment, suitable for both desktop
-	  and server systems.
-
-	  This is the default I/O scheduler.
-
-config CFQ_GROUP_IOSCHED
-	bool "CFQ Group Scheduling support"
-	depends on IOSCHED_CFQ && BLK_CGROUP
-	---help---
-	  Enable group IO scheduling in CFQ.
-
-choice
-
-	prompt "Default I/O scheduler"
-	default DEFAULT_CFQ
-	help
-	  Select the I/O scheduler which will be used by default for all
-	  block devices.
-
-	config DEFAULT_DEADLINE
-		bool "Deadline" if IOSCHED_DEADLINE=y
-
-	config DEFAULT_CFQ
-		bool "CFQ" if IOSCHED_CFQ=y
-
-	config DEFAULT_NOOP
-		bool "No-op"
-
-endchoice
-
-config DEFAULT_IOSCHED
-	string
-	default "deadline" if DEFAULT_DEADLINE
-	default "cfq" if DEFAULT_CFQ
-	default "noop" if DEFAULT_NOOP
-
 config MQ_IOSCHED_DEADLINE
 	tristate "MQ deadline I/O scheduler"
 	default y
diff --git a/block/Makefile b/block/Makefile
index 213674c8faaa..eee1b4ceecf9 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -18,9 +18,6 @@ obj-$(CONFIG_BLK_DEV_BSGLIB)	+= bsg-lib.o
 obj-$(CONFIG_BLK_CGROUP)	+= blk-cgroup.o
 obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_BLK_CGROUP_IOLATENCY)	+= blk-iolatency.o
-obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
-obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
-obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
 obj-$(CONFIG_MQ_IOSCHED_DEADLINE)	+= mq-deadline.o
 obj-$(CONFIG_MQ_IOSCHED_KYBER)	+= kyber-iosched.o
 bfq-y				:= bfq-iosched.o bfq-wf2q.o bfq-cgroup.o
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
deleted file mode 100644
index ed41aa978c4a..000000000000
--- a/block/cfq-iosched.c
+++ /dev/null
@@ -1,4916 +0,0 @@
-/*
- *  CFQ, or complete fairness queueing, disk scheduler.
- *
- *  Based on ideas from a previously unfinished io
- *  scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
- *
- *  Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
- */
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/sched/clock.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/ktime.h>
-#include <linux/rbtree.h>
-#include <linux/ioprio.h>
-#include <linux/blktrace_api.h>
-#include <linux/blk-cgroup.h>
-#include "blk.h"
-#include "blk-wbt.h"
-
-/*
- * tunables
- */
-/* max queue in one round of service */
-static const int cfq_quantum = 8;
-static const u64 cfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
-/* maximum backwards seek, in KiB */
-static const int cfq_back_max = 16 * 1024;
-/* penalty of a backwards seek */
-static const int cfq_back_penalty = 2;
-static const u64 cfq_slice_sync = NSEC_PER_SEC / 10;
-static u64 cfq_slice_async = NSEC_PER_SEC / 25;
-static const int cfq_slice_async_rq = 2;
-static u64 cfq_slice_idle = NSEC_PER_SEC / 125;
-static u64 cfq_group_idle = NSEC_PER_SEC / 125;
-static const u64 cfq_target_latency = (u64)NSEC_PER_SEC * 3/10; /* 300 ms */
-static const int cfq_hist_divisor = 4;
-
-/*
- * offset from end of queue service tree for idle class
- */
-#define CFQ_IDLE_DELAY		(NSEC_PER_SEC / 5)
-/* offset from end of group service tree under time slice mode */
-#define CFQ_SLICE_MODE_GROUP_DELAY (NSEC_PER_SEC / 5)
-/* offset from end of group service under IOPS mode */
-#define CFQ_IOPS_MODE_GROUP_DELAY (HZ / 5)
-
-/*
- * below this threshold, we consider thinktime immediate
- */
-#define CFQ_MIN_TT		(2 * NSEC_PER_SEC / HZ)
-
-#define CFQ_SLICE_SCALE		(5)
-#define CFQ_HW_QUEUE_MIN	(5)
-#define CFQ_SERVICE_SHIFT       12
-
-#define CFQQ_SEEK_THR		(sector_t)(8 * 100)
-#define CFQQ_CLOSE_THR		(sector_t)(8 * 1024)
-#define CFQQ_SECT_THR_NONROT	(sector_t)(2 * 32)
-#define CFQQ_SEEKY(cfqq)	(hweight32(cfqq->seek_history) > 32/8)
-
-#define RQ_CIC(rq)		icq_to_cic((rq)->elv.icq)
-#define RQ_CFQQ(rq)		(struct cfq_queue *) ((rq)->elv.priv[0])
-#define RQ_CFQG(rq)		(struct cfq_group *) ((rq)->elv.priv[1])
-
-static struct kmem_cache *cfq_pool;
-
-#define CFQ_PRIO_LISTS		IOPRIO_BE_NR
-#define cfq_class_idle(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_rt(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
-
-#define sample_valid(samples)	((samples) > 80)
-#define rb_entry_cfqg(node)	rb_entry((node), struct cfq_group, rb_node)
-
-/* blkio-related constants */
-#define CFQ_WEIGHT_LEGACY_MIN	10
-#define CFQ_WEIGHT_LEGACY_DFL	500
-#define CFQ_WEIGHT_LEGACY_MAX	1000
-
-struct cfq_ttime {
-	u64 last_end_request;
-
-	u64 ttime_total;
-	u64 ttime_mean;
-	unsigned long ttime_samples;
-};
-
-/*
- * Most of our rbtree usage is for sorting with min extraction, so
- * if we cache the leftmost node we don't have to walk down the tree
- * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
- * move this into the elevator for the rq sorting as well.
- */
-struct cfq_rb_root {
-	struct rb_root_cached rb;
-	struct rb_node *rb_rightmost;
-	unsigned count;
-	u64 min_vdisktime;
-	struct cfq_ttime ttime;
-};
-#define CFQ_RB_ROOT	(struct cfq_rb_root) { .rb = RB_ROOT_CACHED, \
-			.rb_rightmost = NULL,			     \
-			.ttime = {.last_end_request = ktime_get_ns(),},}
-
-/*
- * Per process-grouping structure
- */
-struct cfq_queue {
-	/* reference count */
-	int ref;
-	/* various state flags, see below */
-	unsigned int flags;
-	/* parent cfq_data */
-	struct cfq_data *cfqd;
-	/* service_tree member */
-	struct rb_node rb_node;
-	/* service_tree key */
-	u64 rb_key;
-	/* prio tree member */
-	struct rb_node p_node;
-	/* prio tree root we belong to, if any */
-	struct rb_root *p_root;
-	/* sorted list of pending requests */
-	struct rb_root sort_list;
-	/* if fifo isn't expired, next request to serve */
-	struct request *next_rq;
-	/* requests queued in sort_list */
-	int queued[2];
-	/* currently allocated requests */
-	int allocated[2];
-	/* fifo list of requests in sort_list */
-	struct list_head fifo;
-
-	/* time when queue got scheduled in to dispatch first request. */
-	u64 dispatch_start;
-	u64 allocated_slice;
-	u64 slice_dispatch;
-	/* time when first request from queue completed and slice started. */
-	u64 slice_start;
-	u64 slice_end;
-	s64 slice_resid;
-
-	/* pending priority requests */
-	int prio_pending;
-	/* number of requests that are on the dispatch list or inside driver */
-	int dispatched;
-
-	/* io prio of this group */
-	unsigned short ioprio, org_ioprio;
-	unsigned short ioprio_class, org_ioprio_class;
-
-	pid_t pid;
-
-	u32 seek_history;
-	sector_t last_request_pos;
-
-	struct cfq_rb_root *service_tree;
-	struct cfq_queue *new_cfqq;
-	struct cfq_group *cfqg;
-	/* Number of sectors dispatched from queue in single dispatch round */
-	unsigned long nr_sectors;
-};
-
-/*
- * First index in the service_trees.
- * IDLE is handled separately, so it has negative index
- */
-enum wl_class_t {
-	BE_WORKLOAD = 0,
-	RT_WORKLOAD = 1,
-	IDLE_WORKLOAD = 2,
-	CFQ_PRIO_NR,
-};
-
-/*
- * Second index in the service_trees.
- */
-enum wl_type_t {
-	ASYNC_WORKLOAD = 0,
-	SYNC_NOIDLE_WORKLOAD = 1,
-	SYNC_WORKLOAD = 2
-};
-
-struct cfqg_stats {
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	/* number of ios merged */
-	struct blkg_rwstat		merged;
-	/* total time spent on device in ns, may not be accurate w/ queueing */
-	struct blkg_rwstat		service_time;
-	/* total time spent waiting in scheduler queue in ns */
-	struct blkg_rwstat		wait_time;
-	/* number of IOs queued up */
-	struct blkg_rwstat		queued;
-	/* total disk time and nr sectors dispatched by this group */
-	struct blkg_stat		time;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	/* time not charged to this cgroup */
-	struct blkg_stat		unaccounted_time;
-	/* sum of number of ios queued across all samples */
-	struct blkg_stat		avg_queue_size_sum;
-	/* count of samples taken for average */
-	struct blkg_stat		avg_queue_size_samples;
-	/* how many times this group has been removed from service tree */
-	struct blkg_stat		dequeue;
-	/* total time spent waiting for it to be assigned a timeslice. */
-	struct blkg_stat		group_wait_time;
-	/* time spent idling for this blkcg_gq */
-	struct blkg_stat		idle_time;
-	/* total time with empty current active q with other requests queued */
-	struct blkg_stat		empty_time;
-	/* fields after this shouldn't be cleared on stat reset */
-	u64				start_group_wait_time;
-	u64				start_idle_time;
-	u64				start_empty_time;
-	uint16_t			flags;
-#endif	/* CONFIG_DEBUG_BLK_CGROUP */
-#endif	/* CONFIG_CFQ_GROUP_IOSCHED */
-};
-
-/* Per-cgroup data */
-struct cfq_group_data {
-	/* must be the first member */
-	struct blkcg_policy_data cpd;
-
-	unsigned int weight;
-	unsigned int leaf_weight;
-};
-
-/* This is per cgroup per device grouping structure */
-struct cfq_group {
-	/* must be the first member */
-	struct blkg_policy_data pd;
-
-	/* group service_tree member */
-	struct rb_node rb_node;
-
-	/* group service_tree key */
-	u64 vdisktime;
-
-	/*
-	 * The number of active cfqgs and sum of their weights under this
-	 * cfqg.  This covers this cfqg's leaf_weight and all children's
-	 * weights, but does not cover weights of further descendants.
-	 *
-	 * If a cfqg is on the service tree, it's active.  An active cfqg
-	 * also activates its parent and contributes to the children_weight
-	 * of the parent.
-	 */
-	int nr_active;
-	unsigned int children_weight;
-
-	/*
-	 * vfraction is the fraction of vdisktime that the tasks in this
-	 * cfqg are entitled to.  This is determined by compounding the
-	 * ratios walking up from this cfqg to the root.
-	 *
-	 * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all
-	 * vfractions on a service tree is approximately 1.  The sum may
-	 * deviate a bit due to rounding errors and fluctuations caused by
-	 * cfqgs entering and leaving the service tree.
-	 */
-	unsigned int vfraction;
-
-	/*
-	 * There are two weights - (internal) weight is the weight of this
-	 * cfqg against the sibling cfqgs.  leaf_weight is the wight of
-	 * this cfqg against the child cfqgs.  For the root cfqg, both
-	 * weights are kept in sync for backward compatibility.
-	 */
-	unsigned int weight;
-	unsigned int new_weight;
-	unsigned int dev_weight;
-
-	unsigned int leaf_weight;
-	unsigned int new_leaf_weight;
-	unsigned int dev_leaf_weight;
-
-	/* number of cfqq currently on this group */
-	int nr_cfqq;
-
-	/*
-	 * Per group busy queues average. Useful for workload slice calc. We
-	 * create the array for each prio class but at run time it is used
-	 * only for RT and BE class and slot for IDLE class remains unused.
-	 * This is primarily done to avoid confusion and a gcc warning.
-	 */
-	unsigned int busy_queues_avg[CFQ_PRIO_NR];
-	/*
-	 * rr lists of queues with requests. We maintain service trees for
-	 * RT and BE classes. These trees are subdivided in subclasses
-	 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
-	 * class there is no subclassification and all the cfq queues go on
-	 * a single tree service_tree_idle.
-	 * Counts are embedded in the cfq_rb_root
-	 */
-	struct cfq_rb_root service_trees[2][3];
-	struct cfq_rb_root service_tree_idle;
-
-	u64 saved_wl_slice;
-	enum wl_type_t saved_wl_type;
-	enum wl_class_t saved_wl_class;
-
-	/* number of requests that are on the dispatch list or inside driver */
-	int dispatched;
-	struct cfq_ttime ttime;
-	struct cfqg_stats stats;	/* stats for this cfqg */
-
-	/* async queue for each priority case */
-	struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
-	struct cfq_queue *async_idle_cfqq;
-
-};
-
-struct cfq_io_cq {
-	struct io_cq		icq;		/* must be the first member */
-	struct cfq_queue	*cfqq[2];
-	struct cfq_ttime	ttime;
-	int			ioprio;		/* the current ioprio */
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	uint64_t		blkcg_serial_nr; /* the current blkcg serial */
-#endif
-};
-
-/*
- * Per block device queue structure
- */
-struct cfq_data {
-	struct request_queue *queue;
-	/* Root service tree for cfq_groups */
-	struct cfq_rb_root grp_service_tree;
-	struct cfq_group *root_group;
-
-	/*
-	 * The priority currently being served
-	 */
-	enum wl_class_t serving_wl_class;
-	enum wl_type_t serving_wl_type;
-	u64 workload_expires;
-	struct cfq_group *serving_group;
-
-	/*
-	 * Each priority tree is sorted by next_request position.  These
-	 * trees are used when determining if two or more queues are
-	 * interleaving requests (see cfq_close_cooperator).
-	 */
-	struct rb_root prio_trees[CFQ_PRIO_LISTS];
-
-	unsigned int busy_queues;
-	unsigned int busy_sync_queues;
-
-	int rq_in_driver;
-	int rq_in_flight[2];
-
-	/*
-	 * queue-depth detection
-	 */
-	int rq_queued;
-	int hw_tag;
-	/*
-	 * hw_tag can be
-	 * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
-	 *  1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
-	 *  0 => no NCQ
-	 */
-	int hw_tag_est_depth;
-	unsigned int hw_tag_samples;
-
-	/*
-	 * idle window management
-	 */
-	struct hrtimer idle_slice_timer;
-	struct work_struct unplug_work;
-
-	struct cfq_queue *active_queue;
-	struct cfq_io_cq *active_cic;
-
-	sector_t last_position;
-
-	/*
-	 * tunables, see top of file
-	 */
-	unsigned int cfq_quantum;
-	unsigned int cfq_back_penalty;
-	unsigned int cfq_back_max;
-	unsigned int cfq_slice_async_rq;
-	unsigned int cfq_latency;
-	u64 cfq_fifo_expire[2];
-	u64 cfq_slice[2];
-	u64 cfq_slice_idle;
-	u64 cfq_group_idle;
-	u64 cfq_target_latency;
-
-	/*
-	 * Fallback dummy cfqq for extreme OOM conditions
-	 */
-	struct cfq_queue oom_cfqq;
-
-	u64 last_delayed_sync;
-};
-
-static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
-static void cfq_put_queue(struct cfq_queue *cfqq);
-
-static struct cfq_rb_root *st_for(struct cfq_group *cfqg,
-					    enum wl_class_t class,
-					    enum wl_type_t type)
-{
-	if (!cfqg)
-		return NULL;
-
-	if (class == IDLE_WORKLOAD)
-		return &cfqg->service_tree_idle;
-
-	return &cfqg->service_trees[class][type];
-}
-
-enum cfqq_state_flags {
-	CFQ_CFQQ_FLAG_on_rr = 0,	/* on round-robin busy list */
-	CFQ_CFQQ_FLAG_wait_request,	/* waiting for a request */
-	CFQ_CFQQ_FLAG_must_dispatch,	/* must be allowed a dispatch */
-	CFQ_CFQQ_FLAG_must_alloc_slice,	/* per-slice must_alloc flag */
-	CFQ_CFQQ_FLAG_fifo_expire,	/* FIFO checked in this slice */
-	CFQ_CFQQ_FLAG_idle_window,	/* slice idling enabled */
-	CFQ_CFQQ_FLAG_prio_changed,	/* task priority has changed */
-	CFQ_CFQQ_FLAG_slice_new,	/* no requests dispatched in slice */
-	CFQ_CFQQ_FLAG_sync,		/* synchronous queue */
-	CFQ_CFQQ_FLAG_coop,		/* cfqq is shared */
-	CFQ_CFQQ_FLAG_split_coop,	/* shared cfqq will be splitted */
-	CFQ_CFQQ_FLAG_deep,		/* sync cfqq experienced large depth */
-	CFQ_CFQQ_FLAG_wait_busy,	/* Waiting for next request */
-};
-
-#define CFQ_CFQQ_FNS(name)						\
-static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq)		\
-{									\
-	(cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name);			\
-}									\
-static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq)	\
-{									\
-	(cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name);			\
-}									\
-static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq)		\
-{									\
-	return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0;	\
-}
-
-CFQ_CFQQ_FNS(on_rr);
-CFQ_CFQQ_FNS(wait_request);
-CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(must_alloc_slice);
-CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
-CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(slice_new);
-CFQ_CFQQ_FNS(sync);
-CFQ_CFQQ_FNS(coop);
-CFQ_CFQQ_FNS(split_coop);
-CFQ_CFQQ_FNS(deep);
-CFQ_CFQQ_FNS(wait_busy);
-#undef CFQ_CFQQ_FNS
-
-#if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
-
-/* cfqg stats flags */
-enum cfqg_stats_flags {
-	CFQG_stats_waiting = 0,
-	CFQG_stats_idling,
-	CFQG_stats_empty,
-};
-
-#define CFQG_FLAG_FNS(name)						\
-static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats)	\
-{									\
-	stats->flags |= (1 << CFQG_stats_##name);			\
-}									\
-static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats)	\
-{									\
-	stats->flags &= ~(1 << CFQG_stats_##name);			\
-}									\
-static inline int cfqg_stats_##name(struct cfqg_stats *stats)		\
-{									\
-	return (stats->flags & (1 << CFQG_stats_##name)) != 0;		\
-}									\
-
-CFQG_FLAG_FNS(waiting)
-CFQG_FLAG_FNS(idling)
-CFQG_FLAG_FNS(empty)
-#undef CFQG_FLAG_FNS
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats)
-{
-	u64 now;
-
-	if (!cfqg_stats_waiting(stats))
-		return;
-
-	now = ktime_get_ns();
-	if (now > stats->start_group_wait_time)
-		blkg_stat_add(&stats->group_wait_time,
-			      now - stats->start_group_wait_time);
-	cfqg_stats_clear_waiting(stats);
-}
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg,
-						 struct cfq_group *curr_cfqg)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-
-	if (cfqg_stats_waiting(stats))
-		return;
-	if (cfqg == curr_cfqg)
-		return;
-	stats->start_group_wait_time = ktime_get_ns();
-	cfqg_stats_mark_waiting(stats);
-}
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_end_empty_time(struct cfqg_stats *stats)
-{
-	u64 now;
-
-	if (!cfqg_stats_empty(stats))
-		return;
-
-	now = ktime_get_ns();
-	if (now > stats->start_empty_time)
-		blkg_stat_add(&stats->empty_time,
-			      now - stats->start_empty_time);
-	cfqg_stats_clear_empty(stats);
-}
-
-static void cfqg_stats_update_dequeue(struct cfq_group *cfqg)
-{
-	blkg_stat_add(&cfqg->stats.dequeue, 1);
-}
-
-static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-
-	if (blkg_rwstat_total(&stats->queued))
-		return;
-
-	/*
-	 * group is already marked empty. This can happen if cfqq got new
-	 * request in parent group and moved to this group while being added
-	 * to service tree. Just ignore the event and move on.
-	 */
-	if (cfqg_stats_empty(stats))
-		return;
-
-	stats->start_empty_time = ktime_get_ns();
-	cfqg_stats_mark_empty(stats);
-}
-
-static void cfqg_stats_update_idle_time(struct cfq_group *cfqg)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-
-	if (cfqg_stats_idling(stats)) {
-		u64 now = ktime_get_ns();
-
-		if (now > stats->start_idle_time)
-			blkg_stat_add(&stats->idle_time,
-				      now - stats->start_idle_time);
-		cfqg_stats_clear_idling(stats);
-	}
-}
-
-static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-
-	BUG_ON(cfqg_stats_idling(stats));
-
-	stats->start_idle_time = ktime_get_ns();
-	cfqg_stats_mark_idling(stats);
-}
-
-static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-
-	blkg_stat_add(&stats->avg_queue_size_sum,
-		      blkg_rwstat_total(&stats->queued));
-	blkg_stat_add(&stats->avg_queue_size_samples, 1);
-	cfqg_stats_update_group_wait_time(stats);
-}
-
-#else	/* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
-
-static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { }
-static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { }
-static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { }
-
-#endif	/* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-
-static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
-{
-	return pd ? container_of(pd, struct cfq_group, pd) : NULL;
-}
-
-static struct cfq_group_data
-*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
-{
-	return cpd ? container_of(cpd, struct cfq_group_data, cpd) : NULL;
-}
-
-static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
-{
-	return pd_to_blkg(&cfqg->pd);
-}
-
-static struct blkcg_policy blkcg_policy_cfq;
-
-static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg)
-{
-	return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq));
-}
-
-static struct cfq_group_data *blkcg_to_cfqgd(struct blkcg *blkcg)
-{
-	return cpd_to_cfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_cfq));
-}
-
-static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg)
-{
-	struct blkcg_gq *pblkg = cfqg_to_blkg(cfqg)->parent;
-
-	return pblkg ? blkg_to_cfqg(pblkg) : NULL;
-}
-
-static inline bool cfqg_is_descendant(struct cfq_group *cfqg,
-				      struct cfq_group *ancestor)
-{
-	return cgroup_is_descendant(cfqg_to_blkg(cfqg)->blkcg->css.cgroup,
-				    cfqg_to_blkg(ancestor)->blkcg->css.cgroup);
-}
-
-static inline void cfqg_get(struct cfq_group *cfqg)
-{
-	return blkg_get(cfqg_to_blkg(cfqg));
-}
-
-static inline void cfqg_put(struct cfq_group *cfqg)
-{
-	return blkg_put(cfqg_to_blkg(cfqg));
-}
-
-#define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	do {			\
-	blk_add_cgroup_trace_msg((cfqd)->queue,				\
-			cfqg_to_blkg((cfqq)->cfqg)->blkcg,		\
-			"cfq%d%c%c " fmt, (cfqq)->pid,			\
-			cfq_cfqq_sync((cfqq)) ? 'S' : 'A',		\
-			cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
-			  ##args);					\
-} while (0)
-
-#define cfq_log_cfqg(cfqd, cfqg, fmt, args...)	do {			\
-	blk_add_cgroup_trace_msg((cfqd)->queue,				\
-			cfqg_to_blkg(cfqg)->blkcg, fmt, ##args);	\
-} while (0)
-
-static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
-					    struct cfq_group *curr_cfqg,
-					    unsigned int op)
-{
-	blkg_rwstat_add(&cfqg->stats.queued, op, 1);
-	cfqg_stats_end_empty_time(&cfqg->stats);
-	cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg);
-}
-
-static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
-			uint64_t time, unsigned long unaccounted_time)
-{
-	blkg_stat_add(&cfqg->stats.time, time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time);
-#endif
-}
-
-static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg,
-					       unsigned int op)
-{
-	blkg_rwstat_add(&cfqg->stats.queued, op, -1);
-}
-
-static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg,
-					       unsigned int op)
-{
-	blkg_rwstat_add(&cfqg->stats.merged, op, 1);
-}
-
-static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
-						u64 start_time_ns,
-						u64 io_start_time_ns,
-						unsigned int op)
-{
-	struct cfqg_stats *stats = &cfqg->stats;
-	u64 now = ktime_get_ns();
-
-	if (now > io_start_time_ns)
-		blkg_rwstat_add(&stats->service_time, op,
-				now - io_start_time_ns);
-	if (io_start_time_ns > start_time_ns)
-		blkg_rwstat_add(&stats->wait_time, op,
-				io_start_time_ns - start_time_ns);
-}
-
-/* @stats = 0 */
-static void cfqg_stats_reset(struct cfqg_stats *stats)
-{
-	/* queued stats shouldn't be cleared */
-	blkg_rwstat_reset(&stats->merged);
-	blkg_rwstat_reset(&stats->service_time);
-	blkg_rwstat_reset(&stats->wait_time);
-	blkg_stat_reset(&stats->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	blkg_stat_reset(&stats->unaccounted_time);
-	blkg_stat_reset(&stats->avg_queue_size_sum);
-	blkg_stat_reset(&stats->avg_queue_size_samples);
-	blkg_stat_reset(&stats->dequeue);
-	blkg_stat_reset(&stats->group_wait_time);
-	blkg_stat_reset(&stats->idle_time);
-	blkg_stat_reset(&stats->empty_time);
-#endif
-}
-
-/* @to += @from */
-static void cfqg_stats_add_aux(struct cfqg_stats *to, struct cfqg_stats *from)
-{
-	/* queued stats shouldn't be cleared */
-	blkg_rwstat_add_aux(&to->merged, &from->merged);
-	blkg_rwstat_add_aux(&to->service_time, &from->service_time);
-	blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
-	blkg_stat_add_aux(&from->time, &from->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	blkg_stat_add_aux(&to->unaccounted_time, &from->unaccounted_time);
-	blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
-	blkg_stat_add_aux(&to->avg_queue_size_samples, &from->avg_queue_size_samples);
-	blkg_stat_add_aux(&to->dequeue, &from->dequeue);
-	blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
-	blkg_stat_add_aux(&to->idle_time, &from->idle_time);
-	blkg_stat_add_aux(&to->empty_time, &from->empty_time);
-#endif
-}
-
-/*
- * Transfer @cfqg's stats to its parent's aux counts so that the ancestors'
- * recursive stats can still account for the amount used by this cfqg after
- * it's gone.
- */
-static void cfqg_stats_xfer_dead(struct cfq_group *cfqg)
-{
-	struct cfq_group *parent = cfqg_parent(cfqg);
-
-	lockdep_assert_held(cfqg_to_blkg(cfqg)->q->queue_lock);
-
-	if (unlikely(!parent))
-		return;
-
-	cfqg_stats_add_aux(&parent->stats, &cfqg->stats);
-	cfqg_stats_reset(&cfqg->stats);
-}
-
-#else	/* CONFIG_CFQ_GROUP_IOSCHED */
-
-static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) { return NULL; }
-static inline bool cfqg_is_descendant(struct cfq_group *cfqg,
-				      struct cfq_group *ancestor)
-{
-	return true;
-}
-static inline void cfqg_get(struct cfq_group *cfqg) { }
-static inline void cfqg_put(struct cfq_group *cfqg) { }
-
-#define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	\
-	blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid,	\
-			cfq_cfqq_sync((cfqq)) ? 'S' : 'A',		\
-			cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
-				##args)
-#define cfq_log_cfqg(cfqd, cfqg, fmt, args...)		do {} while (0)
-
-static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
-			struct cfq_group *curr_cfqg, unsigned int op) { }
-static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
-			uint64_t time, unsigned long unaccounted_time) { }
-static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg,
-			unsigned int op) { }
-static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg,
-			unsigned int op) { }
-static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
-						u64 start_time_ns,
-						u64 io_start_time_ns,
-						unsigned int op) { }
-
-#endif	/* CONFIG_CFQ_GROUP_IOSCHED */
-
-#define cfq_log(cfqd, fmt, args...)	\
-	blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
-
-/* Traverses through cfq group service trees */
-#define for_each_cfqg_st(cfqg, i, j, st) \
-	for (i = 0; i <= IDLE_WORKLOAD; i++) \
-		for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
-			: &cfqg->service_tree_idle; \
-			(i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
-			(i == IDLE_WORKLOAD && j == 0); \
-			j++, st = i < IDLE_WORKLOAD ? \
-			&cfqg->service_trees[i][j]: NULL) \
-
-static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
-	struct cfq_ttime *ttime, bool group_idle)
-{
-	u64 slice;
-	if (!sample_valid(ttime->ttime_samples))
-		return false;
-	if (group_idle)
-		slice = cfqd->cfq_group_idle;
-	else
-		slice = cfqd->cfq_slice_idle;
-	return ttime->ttime_mean > slice;
-}
-
-static inline bool iops_mode(struct cfq_data *cfqd)
-{
-	/*
-	 * If we are not idling on queues and it is a NCQ drive, parallel
-	 * execution of requests is on and measuring time is not possible
-	 * in most of the cases until and unless we drive shallower queue
-	 * depths and that becomes a performance bottleneck. In such cases
-	 * switch to start providing fairness in terms of number of IOs.
-	 */
-	if (!cfqd->cfq_slice_idle && cfqd->hw_tag)
-		return true;
-	else
-		return false;
-}
-
-static inline enum wl_class_t cfqq_class(struct cfq_queue *cfqq)
-{
-	if (cfq_class_idle(cfqq))
-		return IDLE_WORKLOAD;
-	if (cfq_class_rt(cfqq))
-		return RT_WORKLOAD;
-	return BE_WORKLOAD;
-}
-
-
-static enum wl_type_t cfqq_type(struct cfq_queue *cfqq)
-{
-	if (!cfq_cfqq_sync(cfqq))
-		return ASYNC_WORKLOAD;
-	if (!cfq_cfqq_idle_window(cfqq))
-		return SYNC_NOIDLE_WORKLOAD;
-	return SYNC_WORKLOAD;
-}
-
-static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class,
-					struct cfq_data *cfqd,
-					struct cfq_group *cfqg)
-{
-	if (wl_class == IDLE_WORKLOAD)
-		return cfqg->service_tree_idle.count;
-
-	return cfqg->service_trees[wl_class][ASYNC_WORKLOAD].count +
-		cfqg->service_trees[wl_class][SYNC_NOIDLE_WORKLOAD].count +
-		cfqg->service_trees[wl_class][SYNC_WORKLOAD].count;
-}
-
-static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
-					struct cfq_group *cfqg)
-{
-	return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count +
-		cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count;
-}
-
-static void cfq_dispatch_insert(struct request_queue *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync,
-				       struct cfq_io_cq *cic, struct bio *bio);
-
-static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
-{
-	/* cic->icq is the first member, %NULL will convert to %NULL */
-	return container_of(icq, struct cfq_io_cq, icq);
-}
-
-static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd,
-					       struct io_context *ioc)
-{
-	if (ioc)
-		return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue));
-	return NULL;
-}
-
-static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync)
-{
-	return cic->cfqq[is_sync];
-}
-
-static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
-				bool is_sync)
-{
-	cic->cfqq[is_sync] = cfqq;
-}
-
-static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic)
-{
-	return cic->icq.q->elevator->elevator_data;
-}
-
-/*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
- */
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
-{
-	if (cfqd->busy_queues) {
-		cfq_log(cfqd, "schedule dispatch");
-		kblockd_schedule_work(&cfqd->unplug_work);
-	}
-}
-
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline u64 cfq_prio_slice(struct cfq_data *cfqd, bool sync,
-				 unsigned short prio)
-{
-	u64 base_slice = cfqd->cfq_slice[sync];
-	u64 slice = div_u64(base_slice, CFQ_SLICE_SCALE);
-
-	WARN_ON(prio >= IOPRIO_BE_NR);
-
-	return base_slice + (slice * (4 - prio));
-}
-
-static inline u64
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
-}
-
-/**
- * cfqg_scale_charge - scale disk time charge according to cfqg weight
- * @charge: disk time being charged
- * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT
- *
- * Scale @charge according to @vfraction, which is in range (0, 1].  The
- * scaling is inversely proportional.
- *
- * scaled = charge / vfraction
- *
- * The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
- */
-static inline u64 cfqg_scale_charge(u64 charge,
-				    unsigned int vfraction)
-{
-	u64 c = charge << CFQ_SERVICE_SHIFT;	/* make it fixed point */
-
-	/* charge / vfraction */
-	c <<= CFQ_SERVICE_SHIFT;
-	return div_u64(c, vfraction);
-}
-
-static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
-{
-	s64 delta = (s64)(vdisktime - min_vdisktime);
-	if (delta > 0)
-		min_vdisktime = vdisktime;
-
-	return min_vdisktime;
-}
-
-static void update_min_vdisktime(struct cfq_rb_root *st)
-{
-	if (!RB_EMPTY_ROOT(&st->rb.rb_root)) {
-		struct cfq_group *cfqg = rb_entry_cfqg(st->rb.rb_leftmost);
-
-		st->min_vdisktime = max_vdisktime(st->min_vdisktime,
-						  cfqg->vdisktime);
-	}
-}
-
-/*
- * get averaged number of queues of RT/BE priority.
- * average is updated, with a formula that gives more weight to higher numbers,
- * to quickly follows sudden increases and decrease slowly
- */
-
-static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
-					struct cfq_group *cfqg, bool rt)
-{
-	unsigned min_q, max_q;
-	unsigned mult  = cfq_hist_divisor - 1;
-	unsigned round = cfq_hist_divisor / 2;
-	unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg);
-
-	min_q = min(cfqg->busy_queues_avg[rt], busy);
-	max_q = max(cfqg->busy_queues_avg[rt], busy);
-	cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) /
-		cfq_hist_divisor;
-	return cfqg->busy_queues_avg[rt];
-}
-
-static inline u64
-cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
-	return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT;
-}
-
-static inline u64
-cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	u64 slice = cfq_prio_to_slice(cfqd, cfqq);
-	if (cfqd->cfq_latency) {
-		/*
-		 * interested queues (we consider only the ones with the same
-		 * priority class in the cfq group)
-		 */
-		unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg,
-						cfq_class_rt(cfqq));
-		u64 sync_slice = cfqd->cfq_slice[1];
-		u64 expect_latency = sync_slice * iq;
-		u64 group_slice = cfq_group_slice(cfqd, cfqq->cfqg);
-
-		if (expect_latency > group_slice) {
-			u64 base_low_slice = 2 * cfqd->cfq_slice_idle;
-			u64 low_slice;
-
-			/* scale low_slice according to IO priority
-			 * and sync vs async */
-			low_slice = div64_u64(base_low_slice*slice, sync_slice);
-			low_slice = min(slice, low_slice);
-			/* the adapted slice value is scaled to fit all iqs
-			 * into the target latency */
-			slice = div64_u64(slice*group_slice, expect_latency);
-			slice = max(slice, low_slice);
-		}
-	}
-	return slice;
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	u64 slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
-	u64 now = ktime_get_ns();
-
-	cfqq->slice_start = now;
-	cfqq->slice_end = now + slice;
-	cfqq->allocated_slice = slice;
-	cfq_log_cfqq(cfqd, cfqq, "set_slice=%llu", cfqq->slice_end - now);
-}
-
-/*
- * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
- * isn't valid until the first request from the dispatch is activated
- * and the slice time set.
- */
-static inline bool cfq_slice_used(struct cfq_queue *cfqq)
-{
-	if (cfq_cfqq_slice_new(cfqq))
-		return false;
-	if (ktime_get_ns() < cfqq->slice_end)
-		return false;
-
-	return true;
-}
-
-/*
- * Lifted from AS - choose which of rq1 and rq2 that is best served now.
- * We choose the request that is closest to the head right now. Distance
- * behind the head is penalized and only allowed to a certain extent.
- */
-static struct request *
-cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last)
-{
-	sector_t s1, s2, d1 = 0, d2 = 0;
-	unsigned long back_max;
-#define CFQ_RQ1_WRAP	0x01 /* request 1 wraps */
-#define CFQ_RQ2_WRAP	0x02 /* request 2 wraps */
-	unsigned wrap = 0; /* bit mask: requests behind the disk head? */
-
-	if (rq1 == NULL || rq1 == rq2)
-		return rq2;
-	if (rq2 == NULL)
-		return rq1;
-
-	if (rq_is_sync(rq1) != rq_is_sync(rq2))
-		return rq_is_sync(rq1) ? rq1 : rq2;
-
-	if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO)
-		return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2;
-
-	s1 = blk_rq_pos(rq1);
-	s2 = blk_rq_pos(rq2);
-
-	/*
-	 * by definition, 1KiB is 2 sectors
-	 */
-	back_max = cfqd->cfq_back_max * 2;
-
-	/*
-	 * Strict one way elevator _except_ in the case where we allow
-	 * short backward seeks which are biased as twice the cost of a
-	 * similar forward seek.
-	 */
-	if (s1 >= last)
-		d1 = s1 - last;
-	else if (s1 + back_max >= last)
-		d1 = (last - s1) * cfqd->cfq_back_penalty;
-	else
-		wrap |= CFQ_RQ1_WRAP;
-
-	if (s2 >= last)
-		d2 = s2 - last;
-	else if (s2 + back_max >= last)
-		d2 = (last - s2) * cfqd->cfq_back_penalty;
-	else
-		wrap |= CFQ_RQ2_WRAP;
-
-	/* Found required data */
-
-	/*
-	 * By doing switch() on the bit mask "wrap" we avoid having to
-	 * check two variables for all permutations: --> faster!
-	 */
-	switch (wrap) {
-	case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
-		if (d1 < d2)
-			return rq1;
-		else if (d2 < d1)
-			return rq2;
-		else {
-			if (s1 >= s2)
-				return rq1;
-			else
-				return rq2;
-		}
-
-	case CFQ_RQ2_WRAP:
-		return rq1;
-	case CFQ_RQ1_WRAP:
-		return rq2;
-	case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
-	default:
-		/*
-		 * Since both rqs are wrapped,
-		 * start with the one that's further behind head
-		 * (--> only *one* back seek required),
-		 * since back seek takes more time than forward.
-		 */
-		if (s1 <= s2)
-			return rq1;
-		else
-			return rq2;
-	}
-}
-
-static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
-{
-	/* Service tree is empty */
-	if (!root->count)
-		return NULL;
-
-	return rb_entry(rb_first_cached(&root->rb), struct cfq_queue, rb_node);
-}
-
-static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root)
-{
-	return rb_entry_cfqg(rb_first_cached(&root->rb));
-}
-
-static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
-{
-	if (root->rb_rightmost == n)
-		root->rb_rightmost = rb_prev(n);
-
-	rb_erase_cached(n, &root->rb);
-	RB_CLEAR_NODE(n);
-
-	--root->count;
-}
-
-/*
- * would be nice to take fifo expire time into account as well
- */
-static struct request *
-cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		  struct request *last)
-{
-	struct rb_node *rbnext = rb_next(&last->rb_node);
-	struct rb_node *rbprev = rb_prev(&last->rb_node);
-	struct request *next = NULL, *prev = NULL;
-
-	BUG_ON(RB_EMPTY_NODE(&last->rb_node));
-
-	if (rbprev)
-		prev = rb_entry_rq(rbprev);
-
-	if (rbnext)
-		next = rb_entry_rq(rbnext);
-	else {
-		rbnext = rb_first(&cfqq->sort_list);
-		if (rbnext && rbnext != &last->rb_node)
-			next = rb_entry_rq(rbnext);
-	}
-
-	return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last));
-}
-
-static u64 cfq_slice_offset(struct cfq_data *cfqd,
-			    struct cfq_queue *cfqq)
-{
-	/*
-	 * just an approximation, should be ok.
-	 */
-	return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) -
-		       cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
-}
-
-static inline s64
-cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
-	return cfqg->vdisktime - st->min_vdisktime;
-}
-
-static void
-__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
-	struct rb_node **node = &st->rb.rb_root.rb_node;
-	struct rb_node *parent = NULL;
-	struct cfq_group *__cfqg;
-	s64 key = cfqg_key(st, cfqg);
-	bool leftmost = true, rightmost = true;
-
-	while (*node != NULL) {
-		parent = *node;
-		__cfqg = rb_entry_cfqg(parent);
-
-		if (key < cfqg_key(st, __cfqg)) {
-			node = &parent->rb_left;
-			rightmost = false;
-		} else {
-			node = &parent->rb_right;
-			leftmost = false;
-		}
-	}
-
-	if (rightmost)
-		st->rb_rightmost = &cfqg->rb_node;
-
-	rb_link_node(&cfqg->rb_node, parent, node);
-	rb_insert_color_cached(&cfqg->rb_node, &st->rb, leftmost);
-}
-
-/*
- * This has to be called only on activation of cfqg
- */
-static void
-cfq_update_group_weight(struct cfq_group *cfqg)
-{
-	if (cfqg->new_weight) {
-		cfqg->weight = cfqg->new_weight;
-		cfqg->new_weight = 0;
-	}
-}
-
-static void
-cfq_update_group_leaf_weight(struct cfq_group *cfqg)
-{
-	BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
-
-	if (cfqg->new_leaf_weight) {
-		cfqg->leaf_weight = cfqg->new_leaf_weight;
-		cfqg->new_leaf_weight = 0;
-	}
-}
-
-static void
-cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
-	unsigned int vfr = 1 << CFQ_SERVICE_SHIFT;	/* start with 1 */
-	struct cfq_group *pos = cfqg;
-	struct cfq_group *parent;
-	bool propagate;
-
-	/* add to the service tree */
-	BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
-
-	/*
-	 * Update leaf_weight.  We cannot update weight at this point
-	 * because cfqg might already have been activated and is
-	 * contributing its current weight to the parent's child_weight.
-	 */
-	cfq_update_group_leaf_weight(cfqg);
-	__cfq_group_service_tree_add(st, cfqg);
-
-	/*
-	 * Activate @cfqg and calculate the portion of vfraction @cfqg is
-	 * entitled to.  vfraction is calculated by walking the tree
-	 * towards the root calculating the fraction it has at each level.
-	 * The compounded ratio is how much vfraction @cfqg owns.
-	 *
-	 * Start with the proportion tasks in this cfqg has against active
-	 * children cfqgs - its leaf_weight against children_weight.
-	 */
-	propagate = !pos->nr_active++;
-	pos->children_weight += pos->leaf_weight;
-	vfr = vfr * pos->leaf_weight / pos->children_weight;
-
-	/*
-	 * Compound ->weight walking up the tree.  Both activation and
-	 * vfraction calculation are done in the same loop.  Propagation
-	 * stops once an already activated node is met.  vfraction
-	 * calculation should always continue to the root.
-	 */
-	while ((parent = cfqg_parent(pos))) {
-		if (propagate) {
-			cfq_update_group_weight(pos);
-			propagate = !parent->nr_active++;
-			parent->children_weight += pos->weight;
-		}
-		vfr = vfr * pos->weight / parent->children_weight;
-		pos = parent;
-	}
-
-	cfqg->vfraction = max_t(unsigned, vfr, 1);
-}
-
-static inline u64 cfq_get_cfqg_vdisktime_delay(struct cfq_data *cfqd)
-{
-	if (!iops_mode(cfqd))
-		return CFQ_SLICE_MODE_GROUP_DELAY;
-	else
-		return CFQ_IOPS_MODE_GROUP_DELAY;
-}
-
-static void
-cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
-	struct cfq_rb_root *st = &cfqd->grp_service_tree;
-	struct cfq_group *__cfqg;
-	struct rb_node *n;
-
-	cfqg->nr_cfqq++;
-	if (!RB_EMPTY_NODE(&cfqg->rb_node))
-		return;
-
-	/*
-	 * Currently put the group at the end. Later implement something
-	 * so that groups get lesser vtime based on their weights, so that
-	 * if group does not loose all if it was not continuously backlogged.
-	 */
-	n = st->rb_rightmost;
-	if (n) {
-		__cfqg = rb_entry_cfqg(n);
-		cfqg->vdisktime = __cfqg->vdisktime +
-			cfq_get_cfqg_vdisktime_delay(cfqd);
-	} else
-		cfqg->vdisktime = st->min_vdisktime;
-	cfq_group_service_tree_add(st, cfqg);
-}
-
-static void
-cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
-	struct cfq_group *pos = cfqg;
-	bool propagate;
-
-	/*
-	 * Undo activation from cfq_group_service_tree_add().  Deactivate
-	 * @cfqg and propagate deactivation upwards.
-	 */
-	propagate = !--pos->nr_active;
-	pos->children_weight -= pos->leaf_weight;
-
-	while (propagate) {
-		struct cfq_group *parent = cfqg_parent(pos);
-
-		/* @pos has 0 nr_active at this point */
-		WARN_ON_ONCE(pos->children_weight);
-		pos->vfraction = 0;
-
-		if (!parent)
-			break;
-
-		propagate = !--parent->nr_active;
-		parent->children_weight -= pos->weight;
-		pos = parent;
-	}
-
-	/* remove from the service tree */
-	if (!RB_EMPTY_NODE(&cfqg->rb_node))
-		cfq_rb_erase(&cfqg->rb_node, st);
-}
-
-static void
-cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
-	struct cfq_rb_root *st = &cfqd->grp_service_tree;
-
-	BUG_ON(cfqg->nr_cfqq < 1);
-	cfqg->nr_cfqq--;
-
-	/* If there are other cfq queues under this group, don't delete it */
-	if (cfqg->nr_cfqq)
-		return;
-
-	cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
-	cfq_group_service_tree_del(st, cfqg);
-	cfqg->saved_wl_slice = 0;
-	cfqg_stats_update_dequeue(cfqg);
-}
-
-static inline u64 cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
-				       u64 *unaccounted_time)
-{
-	u64 slice_used;
-	u64 now = ktime_get_ns();
-
-	/*
-	 * Queue got expired before even a single request completed or
-	 * got expired immediately after first request completion.
-	 */
-	if (!cfqq->slice_start || cfqq->slice_start == now) {
-		/*
-		 * Also charge the seek time incurred to the group, otherwise
-		 * if there are mutiple queues in the group, each can dispatch
-		 * a single request on seeky media and cause lots of seek time
-		 * and group will never know it.
-		 */
-		slice_used = max_t(u64, (now - cfqq->dispatch_start),
-					jiffies_to_nsecs(1));
-	} else {
-		slice_used = now - cfqq->slice_start;
-		if (slice_used > cfqq->allocated_slice) {
-			*unaccounted_time = slice_used - cfqq->allocated_slice;
-			slice_used = cfqq->allocated_slice;
-		}
-		if (cfqq->slice_start > cfqq->dispatch_start)
-			*unaccounted_time += cfqq->slice_start -
-					cfqq->dispatch_start;
-	}
-
-	return slice_used;
-}
-
-static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
-				struct cfq_queue *cfqq)
-{
-	struct cfq_rb_root *st = &cfqd->grp_service_tree;
-	u64 used_sl, charge, unaccounted_sl = 0;
-	int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
-			- cfqg->service_tree_idle.count;
-	unsigned int vfr;
-	u64 now = ktime_get_ns();
-
-	BUG_ON(nr_sync < 0);
-	used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl);
-
-	if (iops_mode(cfqd))
-		charge = cfqq->slice_dispatch;
-	else if (!cfq_cfqq_sync(cfqq) && !nr_sync)
-		charge = cfqq->allocated_slice;
-
-	/*
-	 * Can't update vdisktime while on service tree and cfqg->vfraction
-	 * is valid only while on it.  Cache vfr, leave the service tree,
-	 * update vdisktime and go back on.  The re-addition to the tree
-	 * will also update the weights as necessary.
-	 */
-	vfr = cfqg->vfraction;
-	cfq_group_service_tree_del(st, cfqg);
-	cfqg->vdisktime += cfqg_scale_charge(charge, vfr);
-	cfq_group_service_tree_add(st, cfqg);
-
-	/* This group is being expired. Save the context */
-	if (cfqd->workload_expires > now) {
-		cfqg->saved_wl_slice = cfqd->workload_expires - now;
-		cfqg->saved_wl_type = cfqd->serving_wl_type;
-		cfqg->saved_wl_class = cfqd->serving_wl_class;
-	} else
-		cfqg->saved_wl_slice = 0;
-
-	cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
-					st->min_vdisktime);
-	cfq_log_cfqq(cfqq->cfqd, cfqq,
-		     "sl_used=%llu disp=%llu charge=%llu iops=%u sect=%lu",
-		     used_sl, cfqq->slice_dispatch, charge,
-		     iops_mode(cfqd), cfqq->nr_sectors);
-	cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl);
-	cfqg_stats_set_start_empty_time(cfqg);
-}
-
-/**
- * cfq_init_cfqg_base - initialize base part of a cfq_group
- * @cfqg: cfq_group to initialize
- *
- * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
- * is enabled or not.
- */
-static void cfq_init_cfqg_base(struct cfq_group *cfqg)
-{
-	struct cfq_rb_root *st;
-	int i, j;
-
-	for_each_cfqg_st(cfqg, i, j, st)
-		*st = CFQ_RB_ROOT;
-	RB_CLEAR_NODE(&cfqg->rb_node);
-
-	cfqg->ttime.last_end_request = ktime_get_ns();
-}
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
-			    bool on_dfl, bool reset_dev, bool is_leaf_weight);
-
-static void cfqg_stats_exit(struct cfqg_stats *stats)
-{
-	blkg_rwstat_exit(&stats->merged);
-	blkg_rwstat_exit(&stats->service_time);
-	blkg_rwstat_exit(&stats->wait_time);
-	blkg_rwstat_exit(&stats->queued);
-	blkg_stat_exit(&stats->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	blkg_stat_exit(&stats->unaccounted_time);
-	blkg_stat_exit(&stats->avg_queue_size_sum);
-	blkg_stat_exit(&stats->avg_queue_size_samples);
-	blkg_stat_exit(&stats->dequeue);
-	blkg_stat_exit(&stats->group_wait_time);
-	blkg_stat_exit(&stats->idle_time);
-	blkg_stat_exit(&stats->empty_time);
-#endif
-}
-
-static int cfqg_stats_init(struct cfqg_stats *stats, gfp_t gfp)
-{
-	if (blkg_rwstat_init(&stats->merged, gfp) ||
-	    blkg_rwstat_init(&stats->service_time, gfp) ||
-	    blkg_rwstat_init(&stats->wait_time, gfp) ||
-	    blkg_rwstat_init(&stats->queued, gfp) ||
-	    blkg_stat_init(&stats->time, gfp))
-		goto err;
-
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	if (blkg_stat_init(&stats->unaccounted_time, gfp) ||
-	    blkg_stat_init(&stats->avg_queue_size_sum, gfp) ||
-	    blkg_stat_init(&stats->avg_queue_size_samples, gfp) ||
-	    blkg_stat_init(&stats->dequeue, gfp) ||
-	    blkg_stat_init(&stats->group_wait_time, gfp) ||
-	    blkg_stat_init(&stats->idle_time, gfp) ||
-	    blkg_stat_init(&stats->empty_time, gfp))
-		goto err;
-#endif
-	return 0;
-err:
-	cfqg_stats_exit(stats);
-	return -ENOMEM;
-}
-
-static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp)
-{
-	struct cfq_group_data *cgd;
-
-	cgd = kzalloc(sizeof(*cgd), gfp);
-	if (!cgd)
-		return NULL;
-	return &cgd->cpd;
-}
-
-static void cfq_cpd_init(struct blkcg_policy_data *cpd)
-{
-	struct cfq_group_data *cgd = cpd_to_cfqgd(cpd);
-	unsigned int weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
-			      CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
-
-	if (cpd_to_blkcg(cpd) == &blkcg_root)
-		weight *= 2;
-
-	cgd->weight = weight;
-	cgd->leaf_weight = weight;
-}
-
-static void cfq_cpd_free(struct blkcg_policy_data *cpd)
-{
-	kfree(cpd_to_cfqgd(cpd));
-}
-
-static void cfq_cpd_bind(struct blkcg_policy_data *cpd)
-{
-	struct blkcg *blkcg = cpd_to_blkcg(cpd);
-	bool on_dfl = cgroup_subsys_on_dfl(io_cgrp_subsys);
-	unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
-
-	if (blkcg == &blkcg_root)
-		weight *= 2;
-
-	WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, false));
-	WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, true));
-}
-
-static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node)
-{
-	struct cfq_group *cfqg;
-
-	cfqg = kzalloc_node(sizeof(*cfqg), gfp, node);
-	if (!cfqg)
-		return NULL;
-
-	cfq_init_cfqg_base(cfqg);
-	if (cfqg_stats_init(&cfqg->stats, gfp)) {
-		kfree(cfqg);
-		return NULL;
-	}
-
-	return &cfqg->pd;
-}
-
-static void cfq_pd_init(struct blkg_policy_data *pd)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-	struct cfq_group_data *cgd = blkcg_to_cfqgd(pd->blkg->blkcg);
-
-	cfqg->weight = cgd->weight;
-	cfqg->leaf_weight = cgd->leaf_weight;
-}
-
-static void cfq_pd_offline(struct blkg_policy_data *pd)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-	int i;
-
-	for (i = 0; i < IOPRIO_BE_NR; i++) {
-		if (cfqg->async_cfqq[0][i]) {
-			cfq_put_queue(cfqg->async_cfqq[0][i]);
-			cfqg->async_cfqq[0][i] = NULL;
-		}
-		if (cfqg->async_cfqq[1][i]) {
-			cfq_put_queue(cfqg->async_cfqq[1][i]);
-			cfqg->async_cfqq[1][i] = NULL;
-		}
-	}
-
-	if (cfqg->async_idle_cfqq) {
-		cfq_put_queue(cfqg->async_idle_cfqq);
-		cfqg->async_idle_cfqq = NULL;
-	}
-
-	/*
-	 * @blkg is going offline and will be ignored by
-	 * blkg_[rw]stat_recursive_sum().  Transfer stats to the parent so
-	 * that they don't get lost.  If IOs complete after this point, the
-	 * stats for them will be lost.  Oh well...
-	 */
-	cfqg_stats_xfer_dead(cfqg);
-}
-
-static void cfq_pd_free(struct blkg_policy_data *pd)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-
-	cfqg_stats_exit(&cfqg->stats);
-	return kfree(cfqg);
-}
-
-static void cfq_pd_reset_stats(struct blkg_policy_data *pd)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-
-	cfqg_stats_reset(&cfqg->stats);
-}
-
-static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
-					 struct blkcg *blkcg)
-{
-	struct blkcg_gq *blkg;
-
-	blkg = blkg_lookup(blkcg, cfqd->queue);
-	if (likely(blkg))
-		return blkg_to_cfqg(blkg);
-	return NULL;
-}
-
-static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
-{
-	cfqq->cfqg = cfqg;
-	/* cfqq reference on cfqg */
-	cfqg_get(cfqg);
-}
-
-static u64 cfqg_prfill_weight_device(struct seq_file *sf,
-				     struct blkg_policy_data *pd, int off)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-
-	if (!cfqg->dev_weight)
-		return 0;
-	return __blkg_prfill_u64(sf, pd, cfqg->dev_weight);
-}
-
-static int cfqg_print_weight_device(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_weight_device, &blkcg_policy_cfq,
-			  0, false);
-	return 0;
-}
-
-static u64 cfqg_prfill_leaf_weight_device(struct seq_file *sf,
-					  struct blkg_policy_data *pd, int off)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-
-	if (!cfqg->dev_leaf_weight)
-		return 0;
-	return __blkg_prfill_u64(sf, pd, cfqg->dev_leaf_weight);
-}
-
-static int cfqg_print_leaf_weight_device(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_leaf_weight_device, &blkcg_policy_cfq,
-			  0, false);
-	return 0;
-}
-
-static int cfq_print_weight(struct seq_file *sf, void *v)
-{
-	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
-	struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
-	unsigned int val = 0;
-
-	if (cgd)
-		val = cgd->weight;
-
-	seq_printf(sf, "%u\n", val);
-	return 0;
-}
-
-static int cfq_print_leaf_weight(struct seq_file *sf, void *v)
-{
-	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
-	struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
-	unsigned int val = 0;
-
-	if (cgd)
-		val = cgd->leaf_weight;
-
-	seq_printf(sf, "%u\n", val);
-	return 0;
-}
-
-static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
-					char *buf, size_t nbytes, loff_t off,
-					bool on_dfl, bool is_leaf_weight)
-{
-	unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
-	unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
-	struct blkcg *blkcg = css_to_blkcg(of_css(of));
-	struct blkg_conf_ctx ctx;
-	struct cfq_group *cfqg;
-	struct cfq_group_data *cfqgd;
-	int ret;
-	u64 v;
-
-	ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx);
-	if (ret)
-		return ret;
-
-	if (sscanf(ctx.body, "%llu", &v) == 1) {
-		/* require "default" on dfl */
-		ret = -ERANGE;
-		if (!v && on_dfl)
-			goto out_finish;
-	} else if (!strcmp(strim(ctx.body), "default")) {
-		v = 0;
-	} else {
-		ret = -EINVAL;
-		goto out_finish;
-	}
-
-	cfqg = blkg_to_cfqg(ctx.blkg);
-	cfqgd = blkcg_to_cfqgd(blkcg);
-
-	ret = -ERANGE;
-	if (!v || (v >= min && v <= max)) {
-		if (!is_leaf_weight) {
-			cfqg->dev_weight = v;
-			cfqg->new_weight = v ?: cfqgd->weight;
-		} else {
-			cfqg->dev_leaf_weight = v;
-			cfqg->new_leaf_weight = v ?: cfqgd->leaf_weight;
-		}
-		ret = 0;
-	}
-out_finish:
-	blkg_conf_finish(&ctx);
-	return ret ?: nbytes;
-}
-
-static ssize_t cfqg_set_weight_device(struct kernfs_open_file *of,
-				      char *buf, size_t nbytes, loff_t off)
-{
-	return __cfqg_set_weight_device(of, buf, nbytes, off, false, false);
-}
-
-static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
-					   char *buf, size_t nbytes, loff_t off)
-{
-	return __cfqg_set_weight_device(of, buf, nbytes, off, false, true);
-}
-
-static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
-			    bool on_dfl, bool reset_dev, bool is_leaf_weight)
-{
-	unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
-	unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
-	struct blkcg *blkcg = css_to_blkcg(css);
-	struct blkcg_gq *blkg;
-	struct cfq_group_data *cfqgd;
-	int ret = 0;
-
-	if (val < min || val > max)
-		return -ERANGE;
-
-	spin_lock_irq(&blkcg->lock);
-	cfqgd = blkcg_to_cfqgd(blkcg);
-	if (!cfqgd) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	if (!is_leaf_weight)
-		cfqgd->weight = val;
-	else
-		cfqgd->leaf_weight = val;
-
-	hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
-		struct cfq_group *cfqg = blkg_to_cfqg(blkg);
-
-		if (!cfqg)
-			continue;
-
-		if (!is_leaf_weight) {
-			if (reset_dev)
-				cfqg->dev_weight = 0;
-			if (!cfqg->dev_weight)
-				cfqg->new_weight = cfqgd->weight;
-		} else {
-			if (reset_dev)
-				cfqg->dev_leaf_weight = 0;
-			if (!cfqg->dev_leaf_weight)
-				cfqg->new_leaf_weight = cfqgd->leaf_weight;
-		}
-	}
-
-out:
-	spin_unlock_irq(&blkcg->lock);
-	return ret;
-}
-
-static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
-			  u64 val)
-{
-	return __cfq_set_weight(css, val, false, false, false);
-}
-
-static int cfq_set_leaf_weight(struct cgroup_subsys_state *css,
-			       struct cftype *cft, u64 val)
-{
-	return __cfq_set_weight(css, val, false, false, true);
-}
-
-static int cfqg_print_stat(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
-			  &blkcg_policy_cfq, seq_cft(sf)->private, false);
-	return 0;
-}
-
-static int cfqg_print_rwstat(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
-			  &blkcg_policy_cfq, seq_cft(sf)->private, true);
-	return 0;
-}
-
-static u64 cfqg_prfill_stat_recursive(struct seq_file *sf,
-				      struct blkg_policy_data *pd, int off)
-{
-	u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd),
-					  &blkcg_policy_cfq, off);
-	return __blkg_prfill_u64(sf, pd, sum);
-}
-
-static u64 cfqg_prfill_rwstat_recursive(struct seq_file *sf,
-					struct blkg_policy_data *pd, int off)
-{
-	struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd),
-							&blkcg_policy_cfq, off);
-	return __blkg_prfill_rwstat(sf, pd, &sum);
-}
-
-static int cfqg_print_stat_recursive(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_stat_recursive, &blkcg_policy_cfq,
-			  seq_cft(sf)->private, false);
-	return 0;
-}
-
-static int cfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_rwstat_recursive, &blkcg_policy_cfq,
-			  seq_cft(sf)->private, true);
-	return 0;
-}
-
-static u64 cfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
-			       int off)
-{
-	u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes);
-
-	return __blkg_prfill_u64(sf, pd, sum >> 9);
-}
-
-static int cfqg_print_stat_sectors(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_sectors, &blkcg_policy_cfq, 0, false);
-	return 0;
-}
-
-static u64 cfqg_prfill_sectors_recursive(struct seq_file *sf,
-					 struct blkg_policy_data *pd, int off)
-{
-	struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL,
-					offsetof(struct blkcg_gq, stat_bytes));
-	u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
-		atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
-
-	return __blkg_prfill_u64(sf, pd, sum >> 9);
-}
-
-static int cfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_sectors_recursive, &blkcg_policy_cfq, 0,
-			  false);
-	return 0;
-}
-
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,
-				      struct blkg_policy_data *pd, int off)
-{
-	struct cfq_group *cfqg = pd_to_cfqg(pd);
-	u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples);
-	u64 v = 0;
-
-	if (samples) {
-		v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum);
-		v = div64_u64(v, samples);
-	}
-	__blkg_prfill_u64(sf, pd, v);
-	return 0;
-}
-
-/* print avg_queue_size */
-static int cfqg_print_avg_queue_size(struct seq_file *sf, void *v)
-{
-	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
-			  cfqg_prfill_avg_queue_size, &blkcg_policy_cfq,
-			  0, false);
-	return 0;
-}
-#endif	/* CONFIG_DEBUG_BLK_CGROUP */
-
-static struct cftype cfq_blkcg_legacy_files[] = {
-	/* on root, weight is mapped to leaf_weight */
-	{
-		.name = "weight_device",
-		.flags = CFTYPE_ONLY_ON_ROOT,
-		.seq_show = cfqg_print_leaf_weight_device,
-		.write = cfqg_set_leaf_weight_device,
-	},
-	{
-		.name = "weight",
-		.flags = CFTYPE_ONLY_ON_ROOT,
-		.seq_show = cfq_print_leaf_weight,
-		.write_u64 = cfq_set_leaf_weight,
-	},
-
-	/* no such mapping necessary for !roots */
-	{
-		.name = "weight_device",
-		.flags = CFTYPE_NOT_ON_ROOT,
-		.seq_show = cfqg_print_weight_device,
-		.write = cfqg_set_weight_device,
-	},
-	{
-		.name = "weight",
-		.flags = CFTYPE_NOT_ON_ROOT,
-		.seq_show = cfq_print_weight,
-		.write_u64 = cfq_set_weight,
-	},
-
-	{
-		.name = "leaf_weight_device",
-		.seq_show = cfqg_print_leaf_weight_device,
-		.write = cfqg_set_leaf_weight_device,
-	},
-	{
-		.name = "leaf_weight",
-		.seq_show = cfq_print_leaf_weight,
-		.write_u64 = cfq_set_leaf_weight,
-	},
-
-	/* statistics, covers only the tasks in the cfqg */
-	{
-		.name = "time",
-		.private = offsetof(struct cfq_group, stats.time),
-		.seq_show = cfqg_print_stat,
-	},
-	{
-		.name = "sectors",
-		.seq_show = cfqg_print_stat_sectors,
-	},
-	{
-		.name = "io_service_bytes",
-		.private = (unsigned long)&blkcg_policy_cfq,
-		.seq_show = blkg_print_stat_bytes,
-	},
-	{
-		.name = "io_serviced",
-		.private = (unsigned long)&blkcg_policy_cfq,
-		.seq_show = blkg_print_stat_ios,
-	},
-	{
-		.name = "io_service_time",
-		.private = offsetof(struct cfq_group, stats.service_time),
-		.seq_show = cfqg_print_rwstat,
-	},
-	{
-		.name = "io_wait_time",
-		.private = offsetof(struct cfq_group, stats.wait_time),
-		.seq_show = cfqg_print_rwstat,
-	},
-	{
-		.name = "io_merged",
-		.private = offsetof(struct cfq_group, stats.merged),
-		.seq_show = cfqg_print_rwstat,
-	},
-	{
-		.name = "io_queued",
-		.private = offsetof(struct cfq_group, stats.queued),
-		.seq_show = cfqg_print_rwstat,
-	},
-
-	/* the same statictics which cover the cfqg and its descendants */
-	{
-		.name = "time_recursive",
-		.private = offsetof(struct cfq_group, stats.time),
-		.seq_show = cfqg_print_stat_recursive,
-	},
-	{
-		.name = "sectors_recursive",
-		.seq_show = cfqg_print_stat_sectors_recursive,
-	},
-	{
-		.name = "io_service_bytes_recursive",
-		.private = (unsigned long)&blkcg_policy_cfq,
-		.seq_show = blkg_print_stat_bytes_recursive,
-	},
-	{
-		.name = "io_serviced_recursive",
-		.private = (unsigned long)&blkcg_policy_cfq,
-		.seq_show = blkg_print_stat_ios_recursive,
-	},
-	{
-		.name = "io_service_time_recursive",
-		.private = offsetof(struct cfq_group, stats.service_time),
-		.seq_show = cfqg_print_rwstat_recursive,
-	},
-	{
-		.name = "io_wait_time_recursive",
-		.private = offsetof(struct cfq_group, stats.wait_time),
-		.seq_show = cfqg_print_rwstat_recursive,
-	},
-	{
-		.name = "io_merged_recursive",
-		.private = offsetof(struct cfq_group, stats.merged),
-		.seq_show = cfqg_print_rwstat_recursive,
-	},
-	{
-		.name = "io_queued_recursive",
-		.private = offsetof(struct cfq_group, stats.queued),
-		.seq_show = cfqg_print_rwstat_recursive,
-	},
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-	{
-		.name = "avg_queue_size",
-		.seq_show = cfqg_print_avg_queue_size,
-	},
-	{
-		.name = "group_wait_time",
-		.private = offsetof(struct cfq_group, stats.group_wait_time),
-		.seq_show = cfqg_print_stat,
-	},
-	{
-		.name = "idle_time",
-		.private = offsetof(struct cfq_group, stats.idle_time),
-		.seq_show = cfqg_print_stat,
-	},
-	{
-		.name = "empty_time",
-		.private = offsetof(struct cfq_group, stats.empty_time),
-		.seq_show = cfqg_print_stat,
-	},
-	{
-		.name = "dequeue",
-		.private = offsetof(struct cfq_group, stats.dequeue),
-		.seq_show = cfqg_print_stat,
-	},
-	{
-		.name = "unaccounted_time",
-		.private = offsetof(struct cfq_group, stats.unaccounted_time),
-		.seq_show = cfqg_print_stat,
-	},
-#endif	/* CONFIG_DEBUG_BLK_CGROUP */
-	{ }	/* terminate */
-};
-
-static int cfq_print_weight_on_dfl(struct seq_file *sf, void *v)
-{
-	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
-	struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
-
-	seq_printf(sf, "default %u\n", cgd->weight);
-	blkcg_print_blkgs(sf, blkcg, cfqg_prfill_weight_device,
-			  &blkcg_policy_cfq, 0, false);
-	return 0;
-}
-
-static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of,
-				     char *buf, size_t nbytes, loff_t off)
-{
-	char *endp;
-	int ret;
-	u64 v;
-
-	buf = strim(buf);
-
-	/* "WEIGHT" or "default WEIGHT" sets the default weight */
-	v = simple_strtoull(buf, &endp, 0);
-	if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
-		ret = __cfq_set_weight(of_css(of), v, true, false, false);
-		return ret ?: nbytes;
-	}
-
-	/* "MAJ:MIN WEIGHT" */
-	return __cfqg_set_weight_device(of, buf, nbytes, off, true, false);
-}
-
-static struct cftype cfq_blkcg_files[] = {
-	{
-		.name = "weight",
-		.flags = CFTYPE_NOT_ON_ROOT,
-		.seq_show = cfq_print_weight_on_dfl,
-		.write = cfq_set_weight_on_dfl,
-	},
-	{ }	/* terminate */
-};
-
-#else /* GROUP_IOSCHED */
-static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
-					 struct blkcg *blkcg)
-{
-	return cfqd->root_group;
-}
-
-static inline void
-cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) {
-	cfqq->cfqg = cfqg;
-}
-
-#endif /* GROUP_IOSCHED */
-
-/*
- * The cfqd->service_trees holds all pending cfq_queue's that have
- * requests waiting to be processed. It is sorted in the order that
- * we will service the queues.
- */
-static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-				 bool add_front)
-{
-	struct rb_node **p, *parent;
-	struct cfq_queue *__cfqq;
-	u64 rb_key;
-	struct cfq_rb_root *st;
-	bool leftmost = true;
-	int new_cfqq = 1;
-	u64 now = ktime_get_ns();
-
-	st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq));
-	if (cfq_class_idle(cfqq)) {
-		rb_key = CFQ_IDLE_DELAY;
-		parent = st->rb_rightmost;
-		if (parent && parent != &cfqq->rb_node) {
-			__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-			rb_key += __cfqq->rb_key;
-		} else
-			rb_key += now;
-	} else if (!add_front) {
-		/*
-		 * Get our rb key offset. Subtract any residual slice
-		 * value carried from last service. A negative resid
-		 * count indicates slice overrun, and this should position
-		 * the next service time further away in the tree.
-		 */
-		rb_key = cfq_slice_offset(cfqd, cfqq) + now;
-		rb_key -= cfqq->slice_resid;
-		cfqq->slice_resid = 0;
-	} else {
-		rb_key = -NSEC_PER_SEC;
-		__cfqq = cfq_rb_first(st);
-		rb_key += __cfqq ? __cfqq->rb_key : now;
-	}
-
-	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
-		new_cfqq = 0;
-		/*
-		 * same position, nothing more to do
-		 */
-		if (rb_key == cfqq->rb_key && cfqq->service_tree == st)
-			return;
-
-		cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
-		cfqq->service_tree = NULL;
-	}
-
-	parent = NULL;
-	cfqq->service_tree = st;
-	p = &st->rb.rb_root.rb_node;
-	while (*p) {
-		parent = *p;
-		__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-
-		/*
-		 * sort by key, that represents service time.
-		 */
-		if (rb_key < __cfqq->rb_key)
-			p = &parent->rb_left;
-		else {
-			p = &parent->rb_right;
-			leftmost = false;
-		}
-	}
-
-	cfqq->rb_key = rb_key;
-	rb_link_node(&cfqq->rb_node, parent, p);
-	rb_insert_color_cached(&cfqq->rb_node, &st->rb, leftmost);
-	st->count++;
-	if (add_front || !new_cfqq)
-		return;
-	cfq_group_notify_queue_add(cfqd, cfqq->cfqg);
-}
-
-static struct cfq_queue *
-cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
-		     sector_t sector, struct rb_node **ret_parent,
-		     struct rb_node ***rb_link)
-{
-	struct rb_node **p, *parent;
-	struct cfq_queue *cfqq = NULL;
-
-	parent = NULL;
-	p = &root->rb_node;
-	while (*p) {
-		struct rb_node **n;
-
-		parent = *p;
-		cfqq = rb_entry(parent, struct cfq_queue, p_node);
-
-		/*
-		 * Sort strictly based on sector.  Smallest to the left,
-		 * largest to the right.
-		 */
-		if (sector > blk_rq_pos(cfqq->next_rq))
-			n = &(*p)->rb_right;
-		else if (sector < blk_rq_pos(cfqq->next_rq))
-			n = &(*p)->rb_left;
-		else
-			break;
-		p = n;
-		cfqq = NULL;
-	}
-
-	*ret_parent = parent;
-	if (rb_link)
-		*rb_link = p;
-	return cfqq;
-}
-
-static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	struct rb_node **p, *parent;
-	struct cfq_queue *__cfqq;
-
-	if (cfqq->p_root) {
-		rb_erase(&cfqq->p_node, cfqq->p_root);
-		cfqq->p_root = NULL;
-	}
-
-	if (cfq_class_idle(cfqq))
-		return;
-	if (!cfqq->next_rq)
-		return;
-
-	cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio];
-	__cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root,
-				      blk_rq_pos(cfqq->next_rq), &parent, &p);
-	if (!__cfqq) {
-		rb_link_node(&cfqq->p_node, parent, p);
-		rb_insert_color(&cfqq->p_node, cfqq->p_root);
-	} else
-		cfqq->p_root = NULL;
-}
-
-/*
- * Update cfqq's position in the service tree.
- */
-static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	/*
-	 * Resorting requires the cfqq to be on the RR list already.
-	 */
-	if (cfq_cfqq_on_rr(cfqq)) {
-		cfq_service_tree_add(cfqd, cfqq, 0);
-		cfq_prio_tree_add(cfqd, cfqq);
-	}
-}
-
-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-	cfq_mark_cfqq_on_rr(cfqq);
-	cfqd->busy_queues++;
-	if (cfq_cfqq_sync(cfqq))
-		cfqd->busy_sync_queues++;
-
-	cfq_resort_rr_list(cfqd, cfqq);
-}
-
-/*
- * Called when the cfqq no longer has requests pending, remove it from
- * the service tree.
- */
-static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-	cfq_clear_cfqq_on_rr(cfqq);
-
-	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
-		cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
-		cfqq->service_tree = NULL;
-	}
-	if (cfqq->p_root) {
-		rb_erase(&cfqq->p_node, cfqq->p_root);
-		cfqq->p_root = NULL;
-	}
-
-	cfq_group_notify_queue_del(cfqd, cfqq->cfqg);
-	BUG_ON(!cfqd->busy_queues);
-	cfqd->busy_queues--;
-	if (cfq_cfqq_sync(cfqq))
-		cfqd->busy_sync_queues--;
-}
-
-/*
- * rb tree support functions
- */
-static void cfq_del_rq_rb(struct request *rq)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-	const int sync = rq_is_sync(rq);
-
-	BUG_ON(!cfqq->queued[sync]);
-	cfqq->queued[sync]--;
-
-	elv_rb_del(&cfqq->sort_list, rq);
-
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) {
-		/*
-		 * Queue will be deleted from service tree when we actually
-		 * expire it later. Right now just remove it from prio tree
-		 * as it is empty.
-		 */
-		if (cfqq->p_root) {
-			rb_erase(&cfqq->p_node, cfqq->p_root);
-			cfqq->p_root = NULL;
-		}
-	}
-}
-
-static void cfq_add_rq_rb(struct request *rq)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *prev;
-
-	cfqq->queued[rq_is_sync(rq)]++;
-
-	elv_rb_add(&cfqq->sort_list, rq);
-
-	if (!cfq_cfqq_on_rr(cfqq))
-		cfq_add_cfqq_rr(cfqd, cfqq);
-
-	/*
-	 * check if this request is a better next-serve candidate
-	 */
-	prev = cfqq->next_rq;
-	cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position);
-
-	/*
-	 * adjust priority tree position, if ->next_rq changes
-	 */
-	if (prev != cfqq->next_rq)
-		cfq_prio_tree_add(cfqd, cfqq);
-
-	BUG_ON(!cfqq->next_rq);
-}
-
-static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
-{
-	elv_rb_del(&cfqq->sort_list, rq);
-	cfqq->queued[rq_is_sync(rq)]--;
-	cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
-	cfq_add_rq_rb(rq);
-	cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group,
-				 rq->cmd_flags);
-}
-
-static struct request *
-cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
-{
-	struct task_struct *tsk = current;
-	struct cfq_io_cq *cic;
-	struct cfq_queue *cfqq;
-
-	cic = cfq_cic_lookup(cfqd, tsk->io_context);
-	if (!cic)
-		return NULL;
-
-	cfqq = cic_to_cfqq(cic, op_is_sync(bio->bi_opf));
-	if (cfqq)
-		return elv_rb_find(&cfqq->sort_list, bio_end_sector(bio));
-
-	return NULL;
-}
-
-static void cfq_activate_request(struct request_queue *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	cfqd->rq_in_driver++;
-	cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
-						cfqd->rq_in_driver);
-
-	cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
-}
-
-static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	cfqd->rq_in_driver--;
-	cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
-						cfqd->rq_in_driver);
-}
-
-static void cfq_remove_request(struct request *rq)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
-	if (cfqq->next_rq == rq)
-		cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
-
-	list_del_init(&rq->queuelist);
-	cfq_del_rq_rb(rq);
-
-	cfqq->cfqd->rq_queued--;
-	cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
-	if (rq->cmd_flags & REQ_PRIO) {
-		WARN_ON(!cfqq->prio_pending);
-		cfqq->prio_pending--;
-	}
-}
-
-static enum elv_merge cfq_merge(struct request_queue *q, struct request **req,
-		     struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct request *__rq;
-
-	__rq = cfq_find_rq_fmerge(cfqd, bio);
-	if (__rq && elv_bio_merge_ok(__rq, bio)) {
-		*req = __rq;
-		return ELEVATOR_FRONT_MERGE;
-	}
-
-	return ELEVATOR_NO_MERGE;
-}
-
-static void cfq_merged_request(struct request_queue *q, struct request *req,
-			       enum elv_merge type)
-{
-	if (type == ELEVATOR_FRONT_MERGE) {
-		struct cfq_queue *cfqq = RQ_CFQQ(req);
-
-		cfq_reposition_rq_rb(cfqq, req);
-	}
-}
-
-static void cfq_bio_merged(struct request_queue *q, struct request *req,
-				struct bio *bio)
-{
-	cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_opf);
-}
-
-static void
-cfq_merged_requests(struct request_queue *q, struct request *rq,
-		    struct request *next)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	/*
-	 * reposition in fifo if next is older than rq
-	 */
-	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
-	    next->fifo_time < rq->fifo_time &&
-	    cfqq == RQ_CFQQ(next)) {
-		list_move(&rq->queuelist, &next->queuelist);
-		rq->fifo_time = next->fifo_time;
-	}
-
-	if (cfqq->next_rq == next)
-		cfqq->next_rq = rq;
-	cfq_remove_request(next);
-	cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags);
-
-	cfqq = RQ_CFQQ(next);
-	/*
-	 * all requests of this queue are merged to other queues, delete it
-	 * from the service tree. If it's the active_queue,
-	 * cfq_dispatch_requests() will choose to expire it or do idle
-	 */
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) &&
-	    cfqq != cfqd->active_queue)
-		cfq_del_cfqq_rr(cfqd, cfqq);
-}
-
-static int cfq_allow_bio_merge(struct request_queue *q, struct request *rq,
-			       struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	bool is_sync = op_is_sync(bio->bi_opf);
-	struct cfq_io_cq *cic;
-	struct cfq_queue *cfqq;
-
-	/*
-	 * Disallow merge of a sync bio into an async request.
-	 */
-	if (is_sync && !rq_is_sync(rq))
-		return false;
-
-	/*
-	 * Lookup the cfqq that this bio will be queued with and allow
-	 * merge only if rq is queued there.
-	 */
-	cic = cfq_cic_lookup(cfqd, current->io_context);
-	if (!cic)
-		return false;
-
-	cfqq = cic_to_cfqq(cic, is_sync);
-	return cfqq == RQ_CFQQ(rq);
-}
-
-static int cfq_allow_rq_merge(struct request_queue *q, struct request *rq,
-			      struct request *next)
-{
-	return RQ_CFQQ(rq) == RQ_CFQQ(next);
-}
-
-static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	hrtimer_try_to_cancel(&cfqd->idle_slice_timer);
-	cfqg_stats_update_idle_time(cfqq->cfqg);
-}
-
-static void __cfq_set_active_queue(struct cfq_data *cfqd,
-				   struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		cfq_log_cfqq(cfqd, cfqq, "set_active wl_class:%d wl_type:%d",
-				cfqd->serving_wl_class, cfqd->serving_wl_type);
-		cfqg_stats_update_avg_queue_size(cfqq->cfqg);
-		cfqq->slice_start = 0;
-		cfqq->dispatch_start = ktime_get_ns();
-		cfqq->allocated_slice = 0;
-		cfqq->slice_end = 0;
-		cfqq->slice_dispatch = 0;
-		cfqq->nr_sectors = 0;
-
-		cfq_clear_cfqq_wait_request(cfqq);
-		cfq_clear_cfqq_must_dispatch(cfqq);
-		cfq_clear_cfqq_must_alloc_slice(cfqq);
-		cfq_clear_cfqq_fifo_expire(cfqq);
-		cfq_mark_cfqq_slice_new(cfqq);
-
-		cfq_del_timer(cfqd, cfqq);
-	}
-
-	cfqd->active_queue = cfqq;
-}
-
-/*
- * current cfqq expired its slice (or was too idle), select new one
- */
-static void
-__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		    bool timed_out)
-{
-	cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
-
-	if (cfq_cfqq_wait_request(cfqq))
-		cfq_del_timer(cfqd, cfqq);
-
-	cfq_clear_cfqq_wait_request(cfqq);
-	cfq_clear_cfqq_wait_busy(cfqq);
-
-	/*
-	 * If this cfqq is shared between multiple processes, check to
-	 * make sure that those processes are still issuing I/Os within
-	 * the mean seek distance.  If not, it may be time to break the
-	 * queues apart again.
-	 */
-	if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq))
-		cfq_mark_cfqq_split_coop(cfqq);
-
-	/*
-	 * store what was left of this slice, if the queue idled/timed out
-	 */
-	if (timed_out) {
-		if (cfq_cfqq_slice_new(cfqq))
-			cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
-		else
-			cfqq->slice_resid = cfqq->slice_end - ktime_get_ns();
-		cfq_log_cfqq(cfqd, cfqq, "resid=%lld", cfqq->slice_resid);
-	}
-
-	cfq_group_served(cfqd, cfqq->cfqg, cfqq);
-
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
-		cfq_del_cfqq_rr(cfqd, cfqq);
-
-	cfq_resort_rr_list(cfqd, cfqq);
-
-	if (cfqq == cfqd->active_queue)
-		cfqd->active_queue = NULL;
-
-	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->icq.ioc);
-		cfqd->active_cic = NULL;
-	}
-}
-
-static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfqq)
-		__cfq_slice_expired(cfqd, cfqq, timed_out);
-}
-
-/*
- * Get next queue for service. Unless we have a queue preemption,
- * we'll simply select the first cfqq in the service tree.
- */
-static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
-{
-	struct cfq_rb_root *st = st_for(cfqd->serving_group,
-			cfqd->serving_wl_class, cfqd->serving_wl_type);
-
-	if (!cfqd->rq_queued)
-		return NULL;
-
-	/* There is nothing to dispatch */
-	if (!st)
-		return NULL;
-	if (RB_EMPTY_ROOT(&st->rb.rb_root))
-		return NULL;
-	return cfq_rb_first(st);
-}
-
-static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd)
-{
-	struct cfq_group *cfqg;
-	struct cfq_queue *cfqq;
-	int i, j;
-	struct cfq_rb_root *st;
-
-	if (!cfqd->rq_queued)
-		return NULL;
-
-	cfqg = cfq_get_next_cfqg(cfqd);
-	if (!cfqg)
-		return NULL;
-
-	for_each_cfqg_st(cfqg, i, j, st) {
-		cfqq = cfq_rb_first(st);
-		if (cfqq)
-			return cfqq;
-	}
-	return NULL;
-}
-
-/*
- * Get and set a new active queue for service.
- */
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
-					      struct cfq_queue *cfqq)
-{
-	if (!cfqq)
-		cfqq = cfq_get_next_queue(cfqd);
-
-	__cfq_set_active_queue(cfqd, cfqq);
-	return cfqq;
-}
-
-static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
-					  struct request *rq)
-{
-	if (blk_rq_pos(rq) >= cfqd->last_position)
-		return blk_rq_pos(rq) - cfqd->last_position;
-	else
-		return cfqd->last_position - blk_rq_pos(rq);
-}
-
-static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			       struct request *rq)
-{
-	return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR;
-}
-
-static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
-				    struct cfq_queue *cur_cfqq)
-{
-	struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio];
-	struct rb_node *parent, *node;
-	struct cfq_queue *__cfqq;
-	sector_t sector = cfqd->last_position;
-
-	if (RB_EMPTY_ROOT(root))
-		return NULL;
-
-	/*
-	 * First, if we find a request starting at the end of the last
-	 * request, choose it.
-	 */
-	__cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL);
-	if (__cfqq)
-		return __cfqq;
-
-	/*
-	 * If the exact sector wasn't found, the parent of the NULL leaf
-	 * will contain the closest sector.
-	 */
-	__cfqq = rb_entry(parent, struct cfq_queue, p_node);
-	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
-		return __cfqq;
-
-	if (blk_rq_pos(__cfqq->next_rq) < sector)
-		node = rb_next(&__cfqq->p_node);
-	else
-		node = rb_prev(&__cfqq->p_node);
-	if (!node)
-		return NULL;
-
-	__cfqq = rb_entry(node, struct cfq_queue, p_node);
-	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
-		return __cfqq;
-
-	return NULL;
-}
-
-/*
- * cfqd - obvious
- * cur_cfqq - passed in so that we don't decide that the current queue is
- * 	      closely cooperating with itself.
- *
- * So, basically we're assuming that that cur_cfqq has dispatched at least
- * one request, and that cfqd->last_position reflects a position on the disk
- * associated with the I/O issued by cur_cfqq.  I'm not sure this is a valid
- * assumption.
- */
-static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
-					      struct cfq_queue *cur_cfqq)
-{
-	struct cfq_queue *cfqq;
-
-	if (cfq_class_idle(cur_cfqq))
-		return NULL;
-	if (!cfq_cfqq_sync(cur_cfqq))
-		return NULL;
-	if (CFQQ_SEEKY(cur_cfqq))
-		return NULL;
-
-	/*
-	 * Don't search priority tree if it's the only queue in the group.
-	 */
-	if (cur_cfqq->cfqg->nr_cfqq == 1)
-		return NULL;
-
-	/*
-	 * We should notice if some of the queues are cooperating, eg
-	 * working closely on the same area of the disk. In that case,
-	 * we can group them together and don't waste time idling.
-	 */
-	cfqq = cfqq_close(cfqd, cur_cfqq);
-	if (!cfqq)
-		return NULL;
-
-	/* If new queue belongs to different cfq_group, don't choose it */
-	if (cur_cfqq->cfqg != cfqq->cfqg)
-		return NULL;
-
-	/*
-	 * It only makes sense to merge sync queues.
-	 */
-	if (!cfq_cfqq_sync(cfqq))
-		return NULL;
-	if (CFQQ_SEEKY(cfqq))
-		return NULL;
-
-	/*
-	 * Do not merge queues of different priority classes
-	 */
-	if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq))
-		return NULL;
-
-	return cfqq;
-}
-
-/*
- * Determine whether we should enforce idle window for this queue.
- */
-
-static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	enum wl_class_t wl_class = cfqq_class(cfqq);
-	struct cfq_rb_root *st = cfqq->service_tree;
-
-	BUG_ON(!st);
-	BUG_ON(!st->count);
-
-	if (!cfqd->cfq_slice_idle)
-		return false;
-
-	/* We never do for idle class queues. */
-	if (wl_class == IDLE_WORKLOAD)
-		return false;
-
-	/* We do for queues that were marked with idle window flag. */
-	if (cfq_cfqq_idle_window(cfqq) &&
-	   !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
-		return true;
-
-	/*
-	 * Otherwise, we do only if they are the last ones
-	 * in their service tree.
-	 */
-	if (st->count == 1 && cfq_cfqq_sync(cfqq) &&
-	   !cfq_io_thinktime_big(cfqd, &st->ttime, false))
-		return true;
-	cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", st->count);
-	return false;
-}
-
-static void cfq_arm_slice_timer(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-	struct cfq_rb_root *st = cfqq->service_tree;
-	struct cfq_io_cq *cic;
-	u64 sl, group_idle = 0;
-	u64 now = ktime_get_ns();
-
-	/*
-	 * SSD device without seek penalty, disable idling. But only do so
-	 * for devices that support queuing, otherwise we still have a problem
-	 * with sync vs async workloads.
-	 */
-	if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag &&
-		!cfqd->cfq_group_idle)
-		return;
-
-	WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
-	WARN_ON(cfq_cfqq_slice_new(cfqq));
-
-	/*
-	 * idle is disabled, either manually or by past process history
-	 */
-	if (!cfq_should_idle(cfqd, cfqq)) {
-		/* no queue idling. Check for group idling */
-		if (cfqd->cfq_group_idle)
-			group_idle = cfqd->cfq_group_idle;
-		else
-			return;
-	}
-
-	/*
-	 * still active requests from this queue, don't idle
-	 */
-	if (cfqq->dispatched)
-		return;
-
-	/*
-	 * task has exited, don't wait
-	 */
-	cic = cfqd->active_cic;
-	if (!cic || !atomic_read(&cic->icq.ioc->active_ref))
-		return;
-
-	/*
-	 * If our average think time is larger than the remaining time
-	 * slice, then don't idle. This avoids overrunning the allotted
-	 * time slice.
-	 */
-	if (sample_valid(cic->ttime.ttime_samples) &&
-	    (cfqq->slice_end - now < cic->ttime.ttime_mean)) {
-		cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%llu",
-			     cic->ttime.ttime_mean);
-		return;
-	}
-
-	/*
-	 * There are other queues in the group or this is the only group and
-	 * it has too big thinktime, don't do group idle.
-	 */
-	if (group_idle &&
-	    (cfqq->cfqg->nr_cfqq > 1 ||
-	     cfq_io_thinktime_big(cfqd, &st->ttime, true)))
-		return;
-
-	cfq_mark_cfqq_wait_request(cfqq);
-
-	if (group_idle)
-		sl = cfqd->cfq_group_idle;
-	else
-		sl = cfqd->cfq_slice_idle;
-
-	hrtimer_start(&cfqd->idle_slice_timer, ns_to_ktime(sl),
-		      HRTIMER_MODE_REL);
-	cfqg_stats_set_start_idle_time(cfqq->cfqg);
-	cfq_log_cfqq(cfqd, cfqq, "arm_idle: %llu group_idle: %d", sl,
-			group_idle ? 1 : 0);
-}
-
-/*
- * Move request from internal lists to the request queue dispatch list.
- */
-static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
-	cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
-
-	cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
-	cfq_remove_request(rq);
-	cfqq->dispatched++;
-	(RQ_CFQG(rq))->dispatched++;
-	elv_dispatch_sort(q, rq);
-
-	cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;
-	cfqq->nr_sectors += blk_rq_sectors(rq);
-}
-
-/*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
-static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
-{
-	struct request *rq = NULL;
-
-	if (cfq_cfqq_fifo_expire(cfqq))
-		return NULL;
-
-	cfq_mark_cfqq_fifo_expire(cfqq);
-
-	if (list_empty(&cfqq->fifo))
-		return NULL;
-
-	rq = rq_entry_fifo(cfqq->fifo.next);
-	if (ktime_get_ns() < rq->fifo_time)
-		rq = NULL;
-
-	return rq;
-}
-
-static inline int
-cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	const int base_rq = cfqd->cfq_slice_async_rq;
-
-	WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
-
-	return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio);
-}
-
-/*
- * Must be called with the queue_lock held.
- */
-static int cfqq_process_refs(struct cfq_queue *cfqq)
-{
-	int process_refs, io_refs;
-
-	io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
-	process_refs = cfqq->ref - io_refs;
-	BUG_ON(process_refs < 0);
-	return process_refs;
-}
-
-static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
-{
-	int process_refs, new_process_refs;
-	struct cfq_queue *__cfqq;
-
-	/*
-	 * If there are no process references on the new_cfqq, then it is
-	 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
-	 * chain may have dropped their last reference (not just their
-	 * last process reference).
-	 */
-	if (!cfqq_process_refs(new_cfqq))
-		return;
-
-	/* Avoid a circular list and skip interim queue merges */
-	while ((__cfqq = new_cfqq->new_cfqq)) {
-		if (__cfqq == cfqq)
-			return;
-		new_cfqq = __cfqq;
-	}
-
-	process_refs = cfqq_process_refs(cfqq);
-	new_process_refs = cfqq_process_refs(new_cfqq);
-	/*
-	 * If the process for the cfqq has gone away, there is no
-	 * sense in merging the queues.
-	 */
-	if (process_refs == 0 || new_process_refs == 0)
-		return;
-
-	/*
-	 * Merge in the direction of the lesser amount of work.
-	 */
-	if (new_process_refs >= process_refs) {
-		cfqq->new_cfqq = new_cfqq;
-		new_cfqq->ref += process_refs;
-	} else {
-		new_cfqq->new_cfqq = cfqq;
-		cfqq->ref += new_process_refs;
-	}
-}
-
-static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd,
-			struct cfq_group *cfqg, enum wl_class_t wl_class)
-{
-	struct cfq_queue *queue;
-	int i;
-	bool key_valid = false;
-	u64 lowest_key = 0;
-	enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
-
-	for (i = 0; i <= SYNC_WORKLOAD; ++i) {
-		/* select the one with lowest rb_key */
-		queue = cfq_rb_first(st_for(cfqg, wl_class, i));
-		if (queue &&
-		    (!key_valid || queue->rb_key < lowest_key)) {
-			lowest_key = queue->rb_key;
-			cur_best = i;
-			key_valid = true;
-		}
-	}
-
-	return cur_best;
-}
-
-static void
-choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
-	u64 slice;
-	unsigned count;
-	struct cfq_rb_root *st;
-	u64 group_slice;
-	enum wl_class_t original_class = cfqd->serving_wl_class;
-	u64 now = ktime_get_ns();
-
-	/* Choose next priority. RT > BE > IDLE */
-	if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
-		cfqd->serving_wl_class = RT_WORKLOAD;
-	else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg))
-		cfqd->serving_wl_class = BE_WORKLOAD;
-	else {
-		cfqd->serving_wl_class = IDLE_WORKLOAD;
-		cfqd->workload_expires = now + jiffies_to_nsecs(1);
-		return;
-	}
-
-	if (original_class != cfqd->serving_wl_class)
-		goto new_workload;
-
-	/*
-	 * For RT and BE, we have to choose also the type
-	 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
-	 * expiration time
-	 */
-	st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type);
-	count = st->count;
-
-	/*
-	 * check workload expiration, and that we still have other queues ready
-	 */
-	if (count && !(now > cfqd->workload_expires))
-		return;
-
-new_workload:
-	/* otherwise select new workload type */
-	cfqd->serving_wl_type = cfq_choose_wl_type(cfqd, cfqg,
-					cfqd->serving_wl_class);
-	st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type);
-	count = st->count;
-
-	/*
-	 * the workload slice is computed as a fraction of target latency
-	 * proportional to the number of queues in that workload, over
-	 * all the queues in the same priority class
-	 */
-	group_slice = cfq_group_slice(cfqd, cfqg);
-
-	slice = div_u64(group_slice * count,
-		max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_wl_class],
-		      cfq_group_busy_queues_wl(cfqd->serving_wl_class, cfqd,
-					cfqg)));
-
-	if (cfqd->serving_wl_type == ASYNC_WORKLOAD) {
-		u64 tmp;
-
-		/*
-		 * Async queues are currently system wide. Just taking
-		 * proportion of queues with-in same group will lead to higher
-		 * async ratio system wide as generally root group is going
-		 * to have higher weight. A more accurate thing would be to
-		 * calculate system wide asnc/sync ratio.
-		 */
-		tmp = cfqd->cfq_target_latency *
-			cfqg_busy_async_queues(cfqd, cfqg);
-		tmp = div_u64(tmp, cfqd->busy_queues);
-		slice = min_t(u64, slice, tmp);
-
-		/* async workload slice is scaled down according to
-		 * the sync/async slice ratio. */
-		slice = div64_u64(slice*cfqd->cfq_slice[0], cfqd->cfq_slice[1]);
-	} else
-		/* sync workload slice is at least 2 * cfq_slice_idle */
-		slice = max(slice, 2 * cfqd->cfq_slice_idle);
-
-	slice = max_t(u64, slice, CFQ_MIN_TT);
-	cfq_log(cfqd, "workload slice:%llu", slice);
-	cfqd->workload_expires = now + slice;
-}
-
-static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
-{
-	struct cfq_rb_root *st = &cfqd->grp_service_tree;
-	struct cfq_group *cfqg;
-
-	if (RB_EMPTY_ROOT(&st->rb.rb_root))
-		return NULL;
-	cfqg = cfq_rb_first_group(st);
-	update_min_vdisktime(st);
-	return cfqg;
-}
-
-static void cfq_choose_cfqg(struct cfq_data *cfqd)
-{
-	struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd);
-	u64 now = ktime_get_ns();
-
-	cfqd->serving_group = cfqg;
-
-	/* Restore the workload type data */
-	if (cfqg->saved_wl_slice) {
-		cfqd->workload_expires = now + cfqg->saved_wl_slice;
-		cfqd->serving_wl_type = cfqg->saved_wl_type;
-		cfqd->serving_wl_class = cfqg->saved_wl_class;
-	} else
-		cfqd->workload_expires = now - 1;
-
-	choose_wl_class_and_type(cfqd, cfqg);
-}
-
-/*
- * Select a queue for service. If we have a current active queue,
- * check whether to continue servicing it, or retrieve and set a new one.
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq, *new_cfqq = NULL;
-	u64 now = ktime_get_ns();
-
-	cfqq = cfqd->active_queue;
-	if (!cfqq)
-		goto new_queue;
-
-	if (!cfqd->rq_queued)
-		return NULL;
-
-	/*
-	 * We were waiting for group to get backlogged. Expire the queue
-	 */
-	if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
-		goto expire;
-
-	/*
-	 * The active queue has run out of time, expire it and select new.
-	 */
-	if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) {
-		/*
-		 * If slice had not expired at the completion of last request
-		 * we might not have turned on wait_busy flag. Don't expire
-		 * the queue yet. Allow the group to get backlogged.
-		 *
-		 * The very fact that we have used the slice, that means we
-		 * have been idling all along on this queue and it should be
-		 * ok to wait for this request to complete.
-		 */
-		if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list)
-		    && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
-			cfqq = NULL;
-			goto keep_queue;
-		} else
-			goto check_group_idle;
-	}
-
-	/*
-	 * The active queue has requests and isn't expired, allow it to
-	 * dispatch.
-	 */
-	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
-		goto keep_queue;
-
-	/*
-	 * If another queue has a request waiting within our mean seek
-	 * distance, let it run.  The expire code will check for close
-	 * cooperators and put the close queue at the front of the service
-	 * tree.  If possible, merge the expiring queue with the new cfqq.
-	 */
-	new_cfqq = cfq_close_cooperator(cfqd, cfqq);
-	if (new_cfqq) {
-		if (!cfqq->new_cfqq)
-			cfq_setup_merge(cfqq, new_cfqq);
-		goto expire;
-	}
-
-	/*
-	 * No requests pending. If the active queue still has requests in
-	 * flight or is idling for a new request, allow either of these
-	 * conditions to happen (or time out) before selecting a new queue.
-	 */
-	if (hrtimer_active(&cfqd->idle_slice_timer)) {
-		cfqq = NULL;
-		goto keep_queue;
-	}
-
-	/*
-	 * This is a deep seek queue, but the device is much faster than
-	 * the queue can deliver, don't idle
-	 **/
-	if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
-	    (cfq_cfqq_slice_new(cfqq) ||
-	    (cfqq->slice_end - now > now - cfqq->slice_start))) {
-		cfq_clear_cfqq_deep(cfqq);
-		cfq_clear_cfqq_idle_window(cfqq);
-	}
-
-	if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
-		cfqq = NULL;
-		goto keep_queue;
-	}
-
-	/*
-	 * If group idle is enabled and there are requests dispatched from
-	 * this group, wait for requests to complete.
-	 */
-check_group_idle:
-	if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 &&
-	    cfqq->cfqg->dispatched &&
-	    !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) {
-		cfqq = NULL;
-		goto keep_queue;
-	}
-
-expire:
-	cfq_slice_expired(cfqd, 0);
-new_queue:
-	/*
-	 * Current queue expired. Check if we have to switch to a new
-	 * service tree
-	 */
-	if (!new_cfqq)
-		cfq_choose_cfqg(cfqd);
-
-	cfqq = cfq_set_active_queue(cfqd, new_cfqq);
-keep_queue:
-	return cfqq;
-}
-
-static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
-{
-	int dispatched = 0;
-
-	while (cfqq->next_rq) {
-		cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
-		dispatched++;
-	}
-
-	BUG_ON(!list_empty(&cfqq->fifo));
-
-	/* By default cfqq is not expired if it is empty. Do it explicitly */
-	__cfq_slice_expired(cfqq->cfqd, cfqq, 0);
-	return dispatched;
-}
-
-/*
- * Drain our current requests. Used for barriers and when switching
- * io schedulers on-the-fly.
- */
-static int cfq_forced_dispatch(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq;
-	int dispatched = 0;
-
-	/* Expire the timeslice of the current active queue first */
-	cfq_slice_expired(cfqd, 0);
-	while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) {
-		__cfq_set_active_queue(cfqd, cfqq);
-		dispatched += __cfq_forced_dispatch_cfqq(cfqq);
-	}
-
-	BUG_ON(cfqd->busy_queues);
-
-	cfq_log(cfqd, "forced_dispatch=%d", dispatched);
-	return dispatched;
-}
-
-static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
-	struct cfq_queue *cfqq)
-{
-	u64 now = ktime_get_ns();
-
-	/* the queue hasn't finished any request, can't estimate */
-	if (cfq_cfqq_slice_new(cfqq))
-		return true;
-	if (now + cfqd->cfq_slice_idle * cfqq->dispatched > cfqq->slice_end)
-		return true;
-
-	return false;
-}
-
-static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	unsigned int max_dispatch;
-
-	if (cfq_cfqq_must_dispatch(cfqq))
-		return true;
-
-	/*
-	 * Drain async requests before we start sync IO
-	 */
-	if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC])
-		return false;
-
-	/*
-	 * If this is an async queue and we have sync IO in flight, let it wait
-	 */
-	if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq))
-		return false;
-
-	max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1);
-	if (cfq_class_idle(cfqq))
-		max_dispatch = 1;
-
-	/*
-	 * Does this cfqq already have too much IO in flight?
-	 */
-	if (cfqq->dispatched >= max_dispatch) {
-		bool promote_sync = false;
-		/*
-		 * idle queue must always only have a single IO in flight
-		 */
-		if (cfq_class_idle(cfqq))
-			return false;
-
-		/*
-		 * If there is only one sync queue
-		 * we can ignore async queue here and give the sync
-		 * queue no dispatch limit. The reason is a sync queue can
-		 * preempt async queue, limiting the sync queue doesn't make
-		 * sense. This is useful for aiostress test.
-		 */
-		if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1)
-			promote_sync = true;
-
-		/*
-		 * We have other queues, don't allow more IO from this one
-		 */
-		if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) &&
-				!promote_sync)
-			return false;
-
-		/*
-		 * Sole queue user, no limit
-		 */
-		if (cfqd->busy_queues == 1 || promote_sync)
-			max_dispatch = -1;
-		else
-			/*
-			 * Normally we start throttling cfqq when cfq_quantum/2
-			 * requests have been dispatched. But we can drive
-			 * deeper queue depths at the beginning of slice
-			 * subjected to upper limit of cfq_quantum.
-			 * */
-			max_dispatch = cfqd->cfq_quantum;
-	}
-
-	/*
-	 * Async queues must wait a bit before being allowed dispatch.
-	 * We also ramp up the dispatch depth gradually for async IO,
-	 * based on the last sync IO we serviced
-	 */
-	if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
-		u64 last_sync = ktime_get_ns() - cfqd->last_delayed_sync;
-		unsigned int depth;
-
-		depth = div64_u64(last_sync, cfqd->cfq_slice[1]);
-		if (!depth && !cfqq->dispatched)
-			depth = 1;
-		if (depth < max_dispatch)
-			max_dispatch = depth;
-	}
-
-	/*
-	 * If we're below the current max, allow a dispatch
-	 */
-	return cfqq->dispatched < max_dispatch;
-}
-
-/*
- * Dispatch a request from cfqq, moving them to the request queue
- * dispatch list.
- */
-static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	struct request *rq;
-
-	BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
-
-	rq = cfq_check_fifo(cfqq);
-	if (rq)
-		cfq_mark_cfqq_must_dispatch(cfqq);
-
-	if (!cfq_may_dispatch(cfqd, cfqq))
-		return false;
-
-	/*
-	 * follow expired path, else get first next available
-	 */
-	if (!rq)
-		rq = cfqq->next_rq;
-	else
-		cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
-
-	/*
-	 * insert request into driver dispatch list
-	 */
-	cfq_dispatch_insert(cfqd->queue, rq);
-
-	if (!cfqd->active_cic) {
-		struct cfq_io_cq *cic = RQ_CIC(rq);
-
-		atomic_long_inc(&cic->icq.ioc->refcount);
-		cfqd->active_cic = cic;
-	}
-
-	return true;
-}
-
-/*
- * Find the cfqq that we need to service and move a request from that to the
- * dispatch list
- */
-static int cfq_dispatch_requests(struct request_queue *q, int force)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq;
-
-	if (!cfqd->busy_queues)
-		return 0;
-
-	if (unlikely(force))
-		return cfq_forced_dispatch(cfqd);
-
-	cfqq = cfq_select_queue(cfqd);
-	if (!cfqq)
-		return 0;
-
-	/*
-	 * Dispatch a request from this cfqq, if it is allowed
-	 */
-	if (!cfq_dispatch_request(cfqd, cfqq))
-		return 0;
-
-	cfqq->slice_dispatch++;
-	cfq_clear_cfqq_must_dispatch(cfqq);
-
-	/*
-	 * expire an async queue immediately if it has used up its slice. idle
-	 * queue always expire after 1 dispatch round.
-	 */
-	if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
-	    cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-	    cfq_class_idle(cfqq))) {
-		cfqq->slice_end = ktime_get_ns() + 1;
-		cfq_slice_expired(cfqd, 0);
-	}
-
-	cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
-	return 1;
-}
-
-/*
- * task holds one reference to the queue, dropped when task exits. each rq
- * in-flight on this queue also holds a reference, dropped when rq is freed.
- *
- * Each cfq queue took a reference on the parent group. Drop it now.
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct cfq_group *cfqg;
-
-	BUG_ON(cfqq->ref <= 0);
-
-	cfqq->ref--;
-	if (cfqq->ref)
-		return;
-
-	cfq_log_cfqq(cfqd, cfqq, "put_queue");
-	BUG_ON(rb_first(&cfqq->sort_list));
-	BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
-	cfqg = cfqq->cfqg;
-
-	if (unlikely(cfqd->active_queue == cfqq)) {
-		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
-	}
-
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-	kmem_cache_free(cfq_pool, cfqq);
-	cfqg_put(cfqg);
-}
-
-static void cfq_put_cooperator(struct cfq_queue *cfqq)
-{
-	struct cfq_queue *__cfqq, *next;
-
-	/*
-	 * If this queue was scheduled to merge with another queue, be
-	 * sure to drop the reference taken on that queue (and others in
-	 * the merge chain).  See cfq_setup_merge and cfq_merge_cfqqs.
-	 */
-	__cfqq = cfqq->new_cfqq;
-	while (__cfqq) {
-		if (__cfqq == cfqq) {
-			WARN(1, "cfqq->new_cfqq loop detected\n");
-			break;
-		}
-		next = __cfqq->new_cfqq;
-		cfq_put_queue(__cfqq);
-		__cfqq = next;
-	}
-}
-
-static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	if (unlikely(cfqq == cfqd->active_queue)) {
-		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
-	}
-
-	cfq_put_cooperator(cfqq);
-
-	cfq_put_queue(cfqq);
-}
-
-static void cfq_init_icq(struct io_cq *icq)
-{
-	struct cfq_io_cq *cic = icq_to_cic(icq);
-
-	cic->ttime.last_end_request = ktime_get_ns();
-}
-
-static void cfq_exit_icq(struct io_cq *icq)
-{
-	struct cfq_io_cq *cic = icq_to_cic(icq);
-	struct cfq_data *cfqd = cic_to_cfqd(cic);
-
-	if (cic_to_cfqq(cic, false)) {
-		cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, false));
-		cic_set_cfqq(cic, NULL, false);
-	}
-
-	if (cic_to_cfqq(cic, true)) {
-		cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, true));
-		cic_set_cfqq(cic, NULL, true);
-	}
-}
-
-static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic)
-{
-	struct task_struct *tsk = current;
-	int ioprio_class;
-
-	if (!cfq_cfqq_prio_changed(cfqq))
-		return;
-
-	ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
-	switch (ioprio_class) {
-	default:
-		printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
-		/* fall through */
-	case IOPRIO_CLASS_NONE:
-		/*
-		 * no prio set, inherit CPU scheduling settings
-		 */
-		cfqq->ioprio = task_nice_ioprio(tsk);
-		cfqq->ioprio_class = task_nice_ioclass(tsk);
-		break;
-	case IOPRIO_CLASS_RT:
-		cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
-		cfqq->ioprio_class = IOPRIO_CLASS_RT;
-		break;
-	case IOPRIO_CLASS_BE:
-		cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
-		cfqq->ioprio_class = IOPRIO_CLASS_BE;
-		break;
-	case IOPRIO_CLASS_IDLE:
-		cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
-		cfqq->ioprio = 7;
-		cfq_clear_cfqq_idle_window(cfqq);
-		break;
-	}
-
-	/*
-	 * keep track of original prio settings in case we have to temporarily
-	 * elevate the priority of this queue
-	 */
-	cfqq->org_ioprio = cfqq->ioprio;
-	cfqq->org_ioprio_class = cfqq->ioprio_class;
-	cfq_clear_cfqq_prio_changed(cfqq);
-}
-
-static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
-	int ioprio = cic->icq.ioc->ioprio;
-	struct cfq_data *cfqd = cic_to_cfqd(cic);
-	struct cfq_queue *cfqq;
-
-	/*
-	 * Check whether ioprio has changed.  The condition may trigger
-	 * spuriously on a newly created cic but there's no harm.
-	 */
-	if (unlikely(!cfqd) || likely(cic->ioprio == ioprio))
-		return;
-
-	cfqq = cic_to_cfqq(cic, false);
-	if (cfqq) {
-		cfq_put_queue(cfqq);
-		cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio);
-		cic_set_cfqq(cic, cfqq, false);
-	}
-
-	cfqq = cic_to_cfqq(cic, true);
-	if (cfqq)
-		cfq_mark_cfqq_prio_changed(cfqq);
-
-	cic->ioprio = ioprio;
-}
-
-static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			  pid_t pid, bool is_sync)
-{
-	RB_CLEAR_NODE(&cfqq->rb_node);
-	RB_CLEAR_NODE(&cfqq->p_node);
-	INIT_LIST_HEAD(&cfqq->fifo);
-
-	cfqq->ref = 0;
-	cfqq->cfqd = cfqd;
-
-	cfq_mark_cfqq_prio_changed(cfqq);
-
-	if (is_sync) {
-		if (!cfq_class_idle(cfqq))
-			cfq_mark_cfqq_idle_window(cfqq);
-		cfq_mark_cfqq_sync(cfqq);
-	}
-	cfqq->pid = pid;
-}
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
-	struct cfq_data *cfqd = cic_to_cfqd(cic);
-	struct cfq_queue *cfqq;
-	uint64_t serial_nr;
-
-	rcu_read_lock();
-	serial_nr = bio_blkcg(bio)->css.serial_nr;
-	rcu_read_unlock();
-
-	/*
-	 * Check whether blkcg has changed.  The condition may trigger
-	 * spuriously on a newly created cic but there's no harm.
-	 */
-	if (unlikely(!cfqd) || likely(cic->blkcg_serial_nr == serial_nr))
-		return;
-
-	/*
-	 * Drop reference to queues.  New queues will be assigned in new
-	 * group upon arrival of fresh requests.
-	 */
-	cfqq = cic_to_cfqq(cic, false);
-	if (cfqq) {
-		cfq_log_cfqq(cfqd, cfqq, "changed cgroup");
-		cic_set_cfqq(cic, NULL, false);
-		cfq_put_queue(cfqq);
-	}
-
-	cfqq = cic_to_cfqq(cic, true);
-	if (cfqq) {
-		cfq_log_cfqq(cfqd, cfqq, "changed cgroup");
-		cic_set_cfqq(cic, NULL, true);
-		cfq_put_queue(cfqq);
-	}
-
-	cic->blkcg_serial_nr = serial_nr;
-}
-#else
-static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
-}
-#endif  /* CONFIG_CFQ_GROUP_IOSCHED */
-
-static struct cfq_queue **
-cfq_async_queue_prio(struct cfq_group *cfqg, int ioprio_class, int ioprio)
-{
-	switch (ioprio_class) {
-	case IOPRIO_CLASS_RT:
-		return &cfqg->async_cfqq[0][ioprio];
-	case IOPRIO_CLASS_NONE:
-		ioprio = IOPRIO_NORM;
-		/* fall through */
-	case IOPRIO_CLASS_BE:
-		return &cfqg->async_cfqq[1][ioprio];
-	case IOPRIO_CLASS_IDLE:
-		return &cfqg->async_idle_cfqq;
-	default:
-		BUG();
-	}
-}
-
-static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
-	      struct bio *bio)
-{
-	int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
-	int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
-	struct cfq_queue **async_cfqq = NULL;
-	struct cfq_queue *cfqq;
-	struct cfq_group *cfqg;
-
-	rcu_read_lock();
-	cfqg = cfq_lookup_cfqg(cfqd, bio_blkcg(bio));
-	if (!cfqg) {
-		cfqq = &cfqd->oom_cfqq;
-		goto out;
-	}
-
-	if (!is_sync) {
-		if (!ioprio_valid(cic->ioprio)) {
-			struct task_struct *tsk = current;
-			ioprio = task_nice_ioprio(tsk);
-			ioprio_class = task_nice_ioclass(tsk);
-		}
-		async_cfqq = cfq_async_queue_prio(cfqg, ioprio_class, ioprio);
-		cfqq = *async_cfqq;
-		if (cfqq)
-			goto out;
-	}
-
-	cfqq = kmem_cache_alloc_node(cfq_pool,
-				     GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN,
-				     cfqd->queue->node);
-	if (!cfqq) {
-		cfqq = &cfqd->oom_cfqq;
-		goto out;
-	}
-
-	/* cfq_init_cfqq() assumes cfqq->ioprio_class is initialized. */
-	cfqq->ioprio_class = IOPRIO_CLASS_NONE;
-	cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
-	cfq_init_prio_data(cfqq, cic);
-	cfq_link_cfqq_cfqg(cfqq, cfqg);
-	cfq_log_cfqq(cfqd, cfqq, "alloced");
-
-	if (async_cfqq) {
-		/* a new async queue is created, pin and remember */
-		cfqq->ref++;
-		*async_cfqq = cfqq;
-	}
-out:
-	cfqq->ref++;
-	rcu_read_unlock();
-	return cfqq;
-}
-
-static void
-__cfq_update_io_thinktime(struct cfq_ttime *ttime, u64 slice_idle)
-{
-	u64 elapsed = ktime_get_ns() - ttime->last_end_request;
-	elapsed = min(elapsed, 2UL * slice_idle);
-
-	ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8;
-	ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed,  8);
-	ttime->ttime_mean = div64_ul(ttime->ttime_total + 128,
-				     ttime->ttime_samples);
-}
-
-static void
-cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			struct cfq_io_cq *cic)
-{
-	if (cfq_cfqq_sync(cfqq)) {
-		__cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle);
-		__cfq_update_io_thinktime(&cfqq->service_tree->ttime,
-			cfqd->cfq_slice_idle);
-	}
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	__cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle);
-#endif
-}
-
-static void
-cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		       struct request *rq)
-{
-	sector_t sdist = 0;
-	sector_t n_sec = blk_rq_sectors(rq);
-	if (cfqq->last_request_pos) {
-		if (cfqq->last_request_pos < blk_rq_pos(rq))
-			sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
-		else
-			sdist = cfqq->last_request_pos - blk_rq_pos(rq);
-	}
-
-	cfqq->seek_history <<= 1;
-	if (blk_queue_nonrot(cfqd->queue))
-		cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT);
-	else
-		cfqq->seek_history |= (sdist > CFQQ_SEEK_THR);
-}
-
-static inline bool req_noidle(struct request *req)
-{
-	return req_op(req) == REQ_OP_WRITE &&
-		(req->cmd_flags & (REQ_SYNC | REQ_IDLE)) == REQ_SYNC;
-}
-
-/*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter
- */
-static void
-cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		       struct cfq_io_cq *cic)
-{
-	int old_idle, enable_idle;
-
-	/*
-	 * Don't idle for async or idle io prio class
-	 */
-	if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
-		return;
-
-	enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
-
-	if (cfqq->queued[0] + cfqq->queued[1] >= 4)
-		cfq_mark_cfqq_deep(cfqq);
-
-	if (cfqq->next_rq && req_noidle(cfqq->next_rq))
-		enable_idle = 0;
-	else if (!atomic_read(&cic->icq.ioc->active_ref) ||
-		 !cfqd->cfq_slice_idle ||
-		 (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
-		enable_idle = 0;
-	else if (sample_valid(cic->ttime.ttime_samples)) {
-		if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle)
-			enable_idle = 0;
-		else
-			enable_idle = 1;
-	}
-
-	if (old_idle != enable_idle) {
-		cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
-		if (enable_idle)
-			cfq_mark_cfqq_idle_window(cfqq);
-		else
-			cfq_clear_cfqq_idle_window(cfqq);
-	}
-}
-
-/*
- * Check if new_cfqq should preempt the currently active queue. Return 0 for
- * no or if we aren't sure, a 1 will cause a preempt.
- */
-static bool
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-		   struct request *rq)
-{
-	struct cfq_queue *cfqq;
-
-	cfqq = cfqd->active_queue;
-	if (!cfqq)
-		return false;
-
-	if (cfq_class_idle(new_cfqq))
-		return false;
-
-	if (cfq_class_idle(cfqq))
-		return true;
-
-	/*
-	 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
-	 */
-	if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
-		return false;
-
-	/*
-	 * if the new request is sync, but the currently running queue is
-	 * not, let the sync request have priority.
-	 */
-	if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
-		return true;
-
-	/*
-	 * Treat ancestors of current cgroup the same way as current cgroup.
-	 * For anybody else we disallow preemption to guarantee service
-	 * fairness among cgroups.
-	 */
-	if (!cfqg_is_descendant(cfqq->cfqg, new_cfqq->cfqg))
-		return false;
-
-	if (cfq_slice_used(cfqq))
-		return true;
-
-	/*
-	 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
-	 */
-	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
-		return true;
-
-	WARN_ON_ONCE(cfqq->ioprio_class != new_cfqq->ioprio_class);
-	/* Allow preemption only if we are idling on sync-noidle tree */
-	if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD &&
-	    cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD &&
-	    RB_EMPTY_ROOT(&cfqq->sort_list))
-		return true;
-
-	/*
-	 * So both queues are sync. Let the new request get disk time if
-	 * it's a metadata request and the current queue is doing regular IO.
-	 */
-	if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
-		return true;
-
-	/* An idle queue should not be idle now for some reason */
-	if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
-		return true;
-
-	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
-		return false;
-
-	/*
-	 * if this request is as-good as one we would expect from the
-	 * current cfqq, let it preempt
-	 */
-	if (cfq_rq_close(cfqd, cfqq, rq))
-		return true;
-
-	return false;
-}
-
-/*
- * cfqq preempts the active queue. if we allowed preempt with no slice left,
- * let it have half of its nominal slice.
- */
-static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	enum wl_type_t old_type = cfqq_type(cfqd->active_queue);
-
-	cfq_log_cfqq(cfqd, cfqq, "preempt");
-	cfq_slice_expired(cfqd, 1);
-
-	/*
-	 * workload type is changed, don't save slice, otherwise preempt
-	 * doesn't happen
-	 */
-	if (old_type != cfqq_type(cfqq))
-		cfqq->cfqg->saved_wl_slice = 0;
-
-	/*
-	 * Put the new queue at the front of the of the current list,
-	 * so we know that it will be selected next.
-	 */
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
-	cfq_service_tree_add(cfqd, cfqq, 1);
-
-	cfqq->slice_end = 0;
-	cfq_mark_cfqq_slice_new(cfqq);
-}
-
-/*
- * Called when a new fs request (rq) is added (to cfqq). Check if there's
- * something we should do about it
- */
-static void
-cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		struct request *rq)
-{
-	struct cfq_io_cq *cic = RQ_CIC(rq);
-
-	cfqd->rq_queued++;
-	if (rq->cmd_flags & REQ_PRIO)
-		cfqq->prio_pending++;
-
-	cfq_update_io_thinktime(cfqd, cfqq, cic);
-	cfq_update_io_seektime(cfqd, cfqq, rq);
-	cfq_update_idle_window(cfqd, cfqq, cic);
-
-	cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
-
-	if (cfqq == cfqd->active_queue) {
-		/*
-		 * Remember that we saw a request from this process, but
-		 * don't start queuing just yet. Otherwise we risk seeing lots
-		 * of tiny requests, because we disrupt the normal plugging
-		 * and merging. If the request is already larger than a single
-		 * page, let it rip immediately. For that case we assume that
-		 * merging is already done. Ditto for a busy system that
-		 * has other work pending, don't risk delaying until the
-		 * idle timer unplug to continue working.
-		 */
-		if (cfq_cfqq_wait_request(cfqq)) {
-			if (blk_rq_bytes(rq) > PAGE_SIZE ||
-			    cfqd->busy_queues > 1) {
-				cfq_del_timer(cfqd, cfqq);
-				cfq_clear_cfqq_wait_request(cfqq);
-				__blk_run_queue(cfqd->queue);
-			} else {
-				cfqg_stats_update_idle_time(cfqq->cfqg);
-				cfq_mark_cfqq_must_dispatch(cfqq);
-			}
-		}
-	} else if (cfq_should_preempt(cfqd, cfqq, rq)) {
-		/*
-		 * not the active queue - expire current slice if it is
-		 * idle and has expired it's mean thinktime or this new queue
-		 * has some old slice time left and is of higher priority or
-		 * this new queue is RT and the current one is BE
-		 */
-		cfq_preempt_queue(cfqd, cfqq);
-		__blk_run_queue(cfqd->queue);
-	}
-}
-
-static void cfq_insert_request(struct request_queue *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
-	cfq_log_cfqq(cfqd, cfqq, "insert_request");
-	cfq_init_prio_data(cfqq, RQ_CIC(rq));
-
-	rq->fifo_time = ktime_get_ns() + cfqd->cfq_fifo_expire[rq_is_sync(rq)];
-	list_add_tail(&rq->queuelist, &cfqq->fifo);
-	cfq_add_rq_rb(rq);
-	cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,
-				 rq->cmd_flags);
-	cfq_rq_enqueued(cfqd, cfqq, rq);
-}
-
-/*
- * Update hw_tag based on peak queue depth over 50 samples under
- * sufficient load.
- */
-static void cfq_update_hw_tag(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth)
-		cfqd->hw_tag_est_depth = cfqd->rq_in_driver;
-
-	if (cfqd->hw_tag == 1)
-		return;
-
-	if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
-	    cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
-		return;
-
-	/*
-	 * If active queue hasn't enough requests and can idle, cfq might not
-	 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
-	 * case
-	 */
-	if (cfqq && cfq_cfqq_idle_window(cfqq) &&
-	    cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] <
-	    CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN)
-		return;
-
-	if (cfqd->hw_tag_samples++ < 50)
-		return;
-
-	if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN)
-		cfqd->hw_tag = 1;
-	else
-		cfqd->hw_tag = 0;
-}
-
-static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	struct cfq_io_cq *cic = cfqd->active_cic;
-	u64 now = ktime_get_ns();
-
-	/* If the queue already has requests, don't wait */
-	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
-		return false;
-
-	/* If there are other queues in the group, don't wait */
-	if (cfqq->cfqg->nr_cfqq > 1)
-		return false;
-
-	/* the only queue in the group, but think time is big */
-	if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true))
-		return false;
-
-	if (cfq_slice_used(cfqq))
-		return true;
-
-	/* if slice left is less than think time, wait busy */
-	if (cic && sample_valid(cic->ttime.ttime_samples)
-	    && (cfqq->slice_end - now < cic->ttime.ttime_mean))
-		return true;
-
-	/*
-	 * If think times is less than a jiffy than ttime_mean=0 and above
-	 * will not be true. It might happen that slice has not expired yet
-	 * but will expire soon (4-5 ns) during select_queue(). To cover the
-	 * case where think time is less than a jiffy, mark the queue wait
-	 * busy if only 1 jiffy is left in the slice.
-	 */
-	if (cfqq->slice_end - now <= jiffies_to_nsecs(1))
-		return true;
-
-	return false;
-}
-
-static void cfq_completed_request(struct request_queue *q, struct request *rq)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-	struct cfq_data *cfqd = cfqq->cfqd;
-	const int sync = rq_is_sync(rq);
-	u64 now = ktime_get_ns();
-
-	cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", req_noidle(rq));
-
-	cfq_update_hw_tag(cfqd);
-
-	WARN_ON(!cfqd->rq_in_driver);
-	WARN_ON(!cfqq->dispatched);
-	cfqd->rq_in_driver--;
-	cfqq->dispatched--;
-	(RQ_CFQG(rq))->dispatched--;
-	cfqg_stats_update_completion(cfqq->cfqg, rq->start_time_ns,
-				     rq->io_start_time_ns, rq->cmd_flags);
-
-	cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--;
-
-	if (sync) {
-		struct cfq_rb_root *st;
-
-		RQ_CIC(rq)->ttime.last_end_request = now;
-
-		if (cfq_cfqq_on_rr(cfqq))
-			st = cfqq->service_tree;
-		else
-			st = st_for(cfqq->cfqg, cfqq_class(cfqq),
-					cfqq_type(cfqq));
-
-		st->ttime.last_end_request = now;
-		if (rq->start_time_ns + cfqd->cfq_fifo_expire[1] <= now)
-			cfqd->last_delayed_sync = now;
-	}
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	cfqq->cfqg->ttime.last_end_request = now;
-#endif
-
-	/*
-	 * If this is the active queue, check if it needs to be expired,
-	 * or if we want to idle in case it has no pending requests.
-	 */
-	if (cfqd->active_queue == cfqq) {
-		const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
-
-		if (cfq_cfqq_slice_new(cfqq)) {
-			cfq_set_prio_slice(cfqd, cfqq);
-			cfq_clear_cfqq_slice_new(cfqq);
-		}
-
-		/*
-		 * Should we wait for next request to come in before we expire
-		 * the queue.
-		 */
-		if (cfq_should_wait_busy(cfqd, cfqq)) {
-			u64 extend_sl = cfqd->cfq_slice_idle;
-			if (!cfqd->cfq_slice_idle)
-				extend_sl = cfqd->cfq_group_idle;
-			cfqq->slice_end = now + extend_sl;
-			cfq_mark_cfqq_wait_busy(cfqq);
-			cfq_log_cfqq(cfqd, cfqq, "will busy wait");
-		}
-
-		/*
-		 * Idling is not enabled on:
-		 * - expired queues
-		 * - idle-priority queues
-		 * - async queues
-		 * - queues with still some requests queued
-		 * - when there is a close cooperator
-		 */
-		if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
-			cfq_slice_expired(cfqd, 1);
-		else if (sync && cfqq_empty &&
-			 !cfq_close_cooperator(cfqd, cfqq)) {
-			cfq_arm_slice_timer(cfqd);
-		}
-	}
-
-	if (!cfqd->rq_in_driver)
-		cfq_schedule_dispatch(cfqd);
-}
-
-static void cfqq_boost_on_prio(struct cfq_queue *cfqq, unsigned int op)
-{
-	/*
-	 * If REQ_PRIO is set, boost class and prio level, if it's below
-	 * BE/NORM. If prio is not set, restore the potentially boosted
-	 * class/prio level.
-	 */
-	if (!(op & REQ_PRIO)) {
-		cfqq->ioprio_class = cfqq->org_ioprio_class;
-		cfqq->ioprio = cfqq->org_ioprio;
-	} else {
-		if (cfq_class_idle(cfqq))
-			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-		if (cfqq->ioprio > IOPRIO_NORM)
-			cfqq->ioprio = IOPRIO_NORM;
-	}
-}
-
-static inline int __cfq_may_queue(struct cfq_queue *cfqq)
-{
-	if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
-		cfq_mark_cfqq_must_alloc_slice(cfqq);
-		return ELV_MQUEUE_MUST;
-	}
-
-	return ELV_MQUEUE_MAY;
-}
-
-static int cfq_may_queue(struct request_queue *q, unsigned int op)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct task_struct *tsk = current;
-	struct cfq_io_cq *cic;
-	struct cfq_queue *cfqq;
-
-	/*
-	 * don't force setup of a queue from here, as a call to may_queue
-	 * does not necessarily imply that a request actually will be queued.
-	 * so just lookup a possibly existing queue, or return 'may queue'
-	 * if that fails
-	 */
-	cic = cfq_cic_lookup(cfqd, tsk->io_context);
-	if (!cic)
-		return ELV_MQUEUE_MAY;
-
-	cfqq = cic_to_cfqq(cic, op_is_sync(op));
-	if (cfqq) {
-		cfq_init_prio_data(cfqq, cic);
-		cfqq_boost_on_prio(cfqq, op);
-
-		return __cfq_may_queue(cfqq);
-	}
-
-	return ELV_MQUEUE_MAY;
-}
-
-/*
- * queue lock held here
- */
-static void cfq_put_request(struct request *rq)
-{
-	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
-	if (cfqq) {
-		const int rw = rq_data_dir(rq);
-
-		BUG_ON(!cfqq->allocated[rw]);
-		cfqq->allocated[rw]--;
-
-		/* Put down rq reference on cfqg */
-		cfqg_put(RQ_CFQG(rq));
-		rq->elv.priv[0] = NULL;
-		rq->elv.priv[1] = NULL;
-
-		cfq_put_queue(cfqq);
-	}
-}
-
-static struct cfq_queue *
-cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic,
-		struct cfq_queue *cfqq)
-{
-	cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
-	cic_set_cfqq(cic, cfqq->new_cfqq, 1);
-	cfq_mark_cfqq_coop(cfqq->new_cfqq);
-	cfq_put_queue(cfqq);
-	return cic_to_cfqq(cic, 1);
-}
-
-/*
- * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
- * was the last process referring to said cfqq.
- */
-static struct cfq_queue *
-split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
-{
-	if (cfqq_process_refs(cfqq) == 1) {
-		cfqq->pid = current->pid;
-		cfq_clear_cfqq_coop(cfqq);
-		cfq_clear_cfqq_split_coop(cfqq);
-		return cfqq;
-	}
-
-	cic_set_cfqq(cic, NULL, 1);
-
-	cfq_put_cooperator(cfqq);
-
-	cfq_put_queue(cfqq);
-	return NULL;
-}
-/*
- * Allocate cfq data structures associated with this request.
- */
-static int
-cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio,
-		gfp_t gfp_mask)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq);
-	const int rw = rq_data_dir(rq);
-	const bool is_sync = rq_is_sync(rq);
-	struct cfq_queue *cfqq;
-
-	spin_lock_irq(q->queue_lock);
-
-	check_ioprio_changed(cic, bio);
-	check_blkcg_changed(cic, bio);
-new_queue:
-	cfqq = cic_to_cfqq(cic, is_sync);
-	if (!cfqq || cfqq == &cfqd->oom_cfqq) {
-		if (cfqq)
-			cfq_put_queue(cfqq);
-		cfqq = cfq_get_queue(cfqd, is_sync, cic, bio);
-		cic_set_cfqq(cic, cfqq, is_sync);
-	} else {
-		/*
-		 * If the queue was seeky for too long, break it apart.
-		 */
-		if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) {
-			cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq");
-			cfqq = split_cfqq(cic, cfqq);
-			if (!cfqq)
-				goto new_queue;
-		}
-
-		/*
-		 * Check to see if this queue is scheduled to merge with
-		 * another, closely cooperating queue.  The merging of
-		 * queues happens here as it must be done in process context.
-		 * The reference on new_cfqq was taken in merge_cfqqs.
-		 */
-		if (cfqq->new_cfqq)
-			cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq);
-	}
-
-	cfqq->allocated[rw]++;
-
-	cfqq->ref++;
-	cfqg_get(cfqq->cfqg);
-	rq->elv.priv[0] = cfqq;
-	rq->elv.priv[1] = cfqq->cfqg;
-	spin_unlock_irq(q->queue_lock);
-
-	return 0;
-}
-
-static void cfq_kick_queue(struct work_struct *work)
-{
-	struct cfq_data *cfqd =
-		container_of(work, struct cfq_data, unplug_work);
-	struct request_queue *q = cfqd->queue;
-
-	spin_lock_irq(q->queue_lock);
-	__blk_run_queue(cfqd->queue);
-	spin_unlock_irq(q->queue_lock);
-}
-
-/*
- * Timer running if the active_queue is currently idling inside its time slice
- */
-static enum hrtimer_restart cfq_idle_slice_timer(struct hrtimer *timer)
-{
-	struct cfq_data *cfqd = container_of(timer, struct cfq_data,
-					     idle_slice_timer);
-	struct cfq_queue *cfqq;
-	unsigned long flags;
-	int timed_out = 1;
-
-	cfq_log(cfqd, "idle timer fired");
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	cfqq = cfqd->active_queue;
-	if (cfqq) {
-		timed_out = 0;
-
-		/*
-		 * We saw a request before the queue expired, let it through
-		 */
-		if (cfq_cfqq_must_dispatch(cfqq))
-			goto out_kick;
-
-		/*
-		 * expired
-		 */
-		if (cfq_slice_used(cfqq))
-			goto expire;
-
-		/*
-		 * only expire and reinvoke request handler, if there are
-		 * other queues with pending requests
-		 */
-		if (!cfqd->busy_queues)
-			goto out_cont;
-
-		/*
-		 * not expired and it has a request pending, let it dispatch
-		 */
-		if (!RB_EMPTY_ROOT(&cfqq->sort_list))
-			goto out_kick;
-
-		/*
-		 * Queue depth flag is reset only when the idle didn't succeed
-		 */
-		cfq_clear_cfqq_deep(cfqq);
-	}
-expire:
-	cfq_slice_expired(cfqd, timed_out);
-out_kick:
-	cfq_schedule_dispatch(cfqd);
-out_cont:
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-	return HRTIMER_NORESTART;
-}
-
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
-{
-	hrtimer_cancel(&cfqd->idle_slice_timer);
-	cancel_work_sync(&cfqd->unplug_work);
-}
-
-static void cfq_exit_queue(struct elevator_queue *e)
-{
-	struct cfq_data *cfqd = e->elevator_data;
-	struct request_queue *q = cfqd->queue;
-
-	cfq_shutdown_timer_wq(cfqd);
-
-	spin_lock_irq(q->queue_lock);
-
-	if (cfqd->active_queue)
-		__cfq_slice_expired(cfqd, cfqd->active_queue, 0);
-
-	spin_unlock_irq(q->queue_lock);
-
-	cfq_shutdown_timer_wq(cfqd);
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	blkcg_deactivate_policy(q, &blkcg_policy_cfq);
-#else
-	kfree(cfqd->root_group);
-#endif
-	kfree(cfqd);
-}
-
-static int cfq_init_queue(struct request_queue *q, struct elevator_type *e)
-{
-	struct cfq_data *cfqd;
-	struct blkcg_gq *blkg __maybe_unused;
-	int i, ret;
-	struct elevator_queue *eq;
-
-	eq = elevator_alloc(q, e);
-	if (!eq)
-		return -ENOMEM;
-
-	cfqd = kzalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
-	if (!cfqd) {
-		kobject_put(&eq->kobj);
-		return -ENOMEM;
-	}
-	eq->elevator_data = cfqd;
-
-	cfqd->queue = q;
-	spin_lock_irq(q->queue_lock);
-	q->elevator = eq;
-	spin_unlock_irq(q->queue_lock);
-
-	/* Init root service tree */
-	cfqd->grp_service_tree = CFQ_RB_ROOT;
-
-	/* Init root group and prefer root group over other groups by default */
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	ret = blkcg_activate_policy(q, &blkcg_policy_cfq);
-	if (ret)
-		goto out_free;
-
-	cfqd->root_group = blkg_to_cfqg(q->root_blkg);
-#else
-	ret = -ENOMEM;
-	cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group),
-					GFP_KERNEL, cfqd->queue->node);
-	if (!cfqd->root_group)
-		goto out_free;
-
-	cfq_init_cfqg_base(cfqd->root_group);
-	cfqd->root_group->weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
-	cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
-#endif
-
-	/*
-	 * Not strictly needed (since RB_ROOT just clears the node and we
-	 * zeroed cfqd on alloc), but better be safe in case someone decides
-	 * to add magic to the rb code
-	 */
-	for (i = 0; i < CFQ_PRIO_LISTS; i++)
-		cfqd->prio_trees[i] = RB_ROOT;
-
-	/*
-	 * Our fallback cfqq if cfq_get_queue() runs into OOM issues.
-	 * Grab a permanent reference to it, so that the normal code flow
-	 * will not attempt to free it.  oom_cfqq is linked to root_group
-	 * but shouldn't hold a reference as it'll never be unlinked.  Lose
-	 * the reference from linking right away.
-	 */
-	cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-	cfqd->oom_cfqq.ref++;
-
-	spin_lock_irq(q->queue_lock);
-	cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group);
-	cfqg_put(cfqd->root_group);
-	spin_unlock_irq(q->queue_lock);
-
-	hrtimer_init(&cfqd->idle_slice_timer, CLOCK_MONOTONIC,
-		     HRTIMER_MODE_REL);
-	cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-
-	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
-
-	cfqd->cfq_quantum = cfq_quantum;
-	cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
-	cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
-	cfqd->cfq_back_max = cfq_back_max;
-	cfqd->cfq_back_penalty = cfq_back_penalty;
-	cfqd->cfq_slice[0] = cfq_slice_async;
-	cfqd->cfq_slice[1] = cfq_slice_sync;
-	cfqd->cfq_target_latency = cfq_target_latency;
-	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
-	cfqd->cfq_slice_idle = cfq_slice_idle;
-	cfqd->cfq_group_idle = cfq_group_idle;
-	cfqd->cfq_latency = 1;
-	cfqd->hw_tag = -1;
-	/*
-	 * we optimistically start assuming sync ops weren't delayed in last
-	 * second, in order to have larger depth for async operations.
-	 */
-	cfqd->last_delayed_sync = ktime_get_ns() - NSEC_PER_SEC;
-	return 0;
-
-out_free:
-	kfree(cfqd);
-	kobject_put(&eq->kobj);
-	return ret;
-}
-
-static void cfq_registered_queue(struct request_queue *q)
-{
-	struct elevator_queue *e = q->elevator;
-	struct cfq_data *cfqd = e->elevator_data;
-
-	/*
-	 * Default to IOPS mode with no idling for SSDs
-	 */
-	if (blk_queue_nonrot(q))
-		cfqd->cfq_slice_idle = 0;
-	wbt_disable_default(q);
-}
-
-/*
- * sysfs parts below -->
- */
-static ssize_t
-cfq_var_show(unsigned int var, char *page)
-{
-	return sprintf(page, "%u\n", var);
-}
-
-static void
-cfq_var_store(unsigned int *var, const char *page)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtoul(p, &p, 10);
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
-static ssize_t __FUNC(struct elevator_queue *e, char *page)		\
-{									\
-	struct cfq_data *cfqd = e->elevator_data;			\
-	u64 __data = __VAR;						\
-	if (__CONV)							\
-		__data = div_u64(__data, NSEC_PER_MSEC);			\
-	return cfq_var_show(__data, (page));				\
-}
-SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
-SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
-SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
-SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0);
-SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
-SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1);
-SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
-SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
-SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
-SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
-SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1);
-#undef SHOW_FUNCTION
-
-#define USEC_SHOW_FUNCTION(__FUNC, __VAR)				\
-static ssize_t __FUNC(struct elevator_queue *e, char *page)		\
-{									\
-	struct cfq_data *cfqd = e->elevator_data;			\
-	u64 __data = __VAR;						\
-	__data = div_u64(__data, NSEC_PER_USEC);			\
-	return cfq_var_show(__data, (page));				\
-}
-USEC_SHOW_FUNCTION(cfq_slice_idle_us_show, cfqd->cfq_slice_idle);
-USEC_SHOW_FUNCTION(cfq_group_idle_us_show, cfqd->cfq_group_idle);
-USEC_SHOW_FUNCTION(cfq_slice_sync_us_show, cfqd->cfq_slice[1]);
-USEC_SHOW_FUNCTION(cfq_slice_async_us_show, cfqd->cfq_slice[0]);
-USEC_SHOW_FUNCTION(cfq_target_latency_us_show, cfqd->cfq_target_latency);
-#undef USEC_SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
-{									\
-	struct cfq_data *cfqd = e->elevator_data;			\
-	unsigned int __data, __min = (MIN), __max = (MAX);		\
-									\
-	cfq_var_store(&__data, (page));					\
-	if (__data < __min)						\
-		__data = __min;						\
-	else if (__data > __max)					\
-		__data = __max;						\
-	if (__CONV)							\
-		*(__PTR) = (u64)__data * NSEC_PER_MSEC;			\
-	else								\
-		*(__PTR) = __data;					\
-	return count;							\
-}
-STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1,
-		UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1,
-		UINT_MAX, 1);
-STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
-STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1,
-		UINT_MAX, 0);
-STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
-		UINT_MAX, 0);
-STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
-STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1);
-#undef STORE_FUNCTION
-
-#define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX)			\
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
-{									\
-	struct cfq_data *cfqd = e->elevator_data;			\
-	unsigned int __data, __min = (MIN), __max = (MAX);		\
-									\
-	cfq_var_store(&__data, (page));					\
-	if (__data < __min)						\
-		__data = __min;						\
-	else if (__data > __max)					\
-		__data = __max;						\
-	*(__PTR) = (u64)__data * NSEC_PER_USEC;				\
-	return count;							\
-}
-USEC_STORE_FUNCTION(cfq_slice_idle_us_store, &cfqd->cfq_slice_idle, 0, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_group_idle_us_store, &cfqd->cfq_group_idle, 0, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_slice_sync_us_store, &cfqd->cfq_slice[1], 1, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_slice_async_us_store, &cfqd->cfq_slice[0], 1, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_target_latency_us_store, &cfqd->cfq_target_latency, 1, UINT_MAX);
-#undef USEC_STORE_FUNCTION
-
-#define CFQ_ATTR(name) \
-	__ATTR(name, 0644, cfq_##name##_show, cfq_##name##_store)
-
-static struct elv_fs_entry cfq_attrs[] = {
-	CFQ_ATTR(quantum),
-	CFQ_ATTR(fifo_expire_sync),
-	CFQ_ATTR(fifo_expire_async),
-	CFQ_ATTR(back_seek_max),
-	CFQ_ATTR(back_seek_penalty),
-	CFQ_ATTR(slice_sync),
-	CFQ_ATTR(slice_sync_us),
-	CFQ_ATTR(slice_async),
-	CFQ_ATTR(slice_async_us),
-	CFQ_ATTR(slice_async_rq),
-	CFQ_ATTR(slice_idle),
-	CFQ_ATTR(slice_idle_us),
-	CFQ_ATTR(group_idle),
-	CFQ_ATTR(group_idle_us),
-	CFQ_ATTR(low_latency),
-	CFQ_ATTR(target_latency),
-	CFQ_ATTR(target_latency_us),
-	__ATTR_NULL
-};
-
-static struct elevator_type iosched_cfq = {
-	.ops.sq = {
-		.elevator_merge_fn = 		cfq_merge,
-		.elevator_merged_fn =		cfq_merged_request,
-		.elevator_merge_req_fn =	cfq_merged_requests,
-		.elevator_allow_bio_merge_fn =	cfq_allow_bio_merge,
-		.elevator_allow_rq_merge_fn =	cfq_allow_rq_merge,
-		.elevator_bio_merged_fn =	cfq_bio_merged,
-		.elevator_dispatch_fn =		cfq_dispatch_requests,
-		.elevator_add_req_fn =		cfq_insert_request,
-		.elevator_activate_req_fn =	cfq_activate_request,
-		.elevator_deactivate_req_fn =	cfq_deactivate_request,
-		.elevator_completed_req_fn =	cfq_completed_request,
-		.elevator_former_req_fn =	elv_rb_former_request,
-		.elevator_latter_req_fn =	elv_rb_latter_request,
-		.elevator_init_icq_fn =		cfq_init_icq,
-		.elevator_exit_icq_fn =		cfq_exit_icq,
-		.elevator_set_req_fn =		cfq_set_request,
-		.elevator_put_req_fn =		cfq_put_request,
-		.elevator_may_queue_fn =	cfq_may_queue,
-		.elevator_init_fn =		cfq_init_queue,
-		.elevator_exit_fn =		cfq_exit_queue,
-		.elevator_registered_fn =	cfq_registered_queue,
-	},
-	.icq_size	=	sizeof(struct cfq_io_cq),
-	.icq_align	=	__alignof__(struct cfq_io_cq),
-	.elevator_attrs =	cfq_attrs,
-	.elevator_name	=	"cfq",
-	.elevator_owner =	THIS_MODULE,
-};
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static struct blkcg_policy blkcg_policy_cfq = {
-	.dfl_cftypes		= cfq_blkcg_files,
-	.legacy_cftypes		= cfq_blkcg_legacy_files,
-
-	.cpd_alloc_fn		= cfq_cpd_alloc,
-	.cpd_init_fn		= cfq_cpd_init,
-	.cpd_free_fn		= cfq_cpd_free,
-	.cpd_bind_fn		= cfq_cpd_bind,
-
-	.pd_alloc_fn		= cfq_pd_alloc,
-	.pd_init_fn		= cfq_pd_init,
-	.pd_offline_fn		= cfq_pd_offline,
-	.pd_free_fn		= cfq_pd_free,
-	.pd_reset_stats_fn	= cfq_pd_reset_stats,
-};
-#endif
-
-static int __init cfq_init(void)
-{
-	int ret;
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	ret = blkcg_policy_register(&blkcg_policy_cfq);
-	if (ret)
-		return ret;
-#else
-	cfq_group_idle = 0;
-#endif
-
-	ret = -ENOMEM;
-	cfq_pool = KMEM_CACHE(cfq_queue, 0);
-	if (!cfq_pool)
-		goto err_pol_unreg;
-
-	ret = elv_register(&iosched_cfq);
-	if (ret)
-		goto err_free_pool;
-
-	return 0;
-
-err_free_pool:
-	kmem_cache_destroy(cfq_pool);
-err_pol_unreg:
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	blkcg_policy_unregister(&blkcg_policy_cfq);
-#endif
-	return ret;
-}
-
-static void __exit cfq_exit(void)
-{
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	blkcg_policy_unregister(&blkcg_policy_cfq);
-#endif
-	elv_unregister(&iosched_cfq);
-	kmem_cache_destroy(cfq_pool);
-}
-
-module_init(cfq_init);
-module_exit(cfq_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
deleted file mode 100644
index ef2f1f09e9b3..000000000000
--- a/block/deadline-iosched.c
+++ /dev/null
@@ -1,560 +0,0 @@
-/*
- *  Deadline i/o scheduler.
- *
- *  Copyright (C) 2002 Jens Axboe <axboe@kernel.dk>
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/rbtree.h>
-
-/*
- * See Documentation/block/deadline-iosched.txt
- */
-static const int read_expire = HZ / 2;  /* max time before a read is submitted. */
-static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
-static const int writes_starved = 2;    /* max times reads can starve a write */
-static const int fifo_batch = 16;       /* # of sequential requests treated as one
-				     by the above parameters. For throughput. */
-
-struct deadline_data {
-	/*
-	 * run time data
-	 */
-
-	/*
-	 * requests (deadline_rq s) are present on both sort_list and fifo_list
-	 */
-	struct rb_root sort_list[2];	
-	struct list_head fifo_list[2];
-
-	/*
-	 * next in sort order. read, write or both are NULL
-	 */
-	struct request *next_rq[2];
-	unsigned int batching;		/* number of sequential requests made */
-	unsigned int starved;		/* times reads have starved writes */
-
-	/*
-	 * settings that change how the i/o scheduler behaves
-	 */
-	int fifo_expire[2];
-	int fifo_batch;
-	int writes_starved;
-	int front_merges;
-};
-
-static inline struct rb_root *
-deadline_rb_root(struct deadline_data *dd, struct request *rq)
-{
-	return &dd->sort_list[rq_data_dir(rq)];
-}
-
-/*
- * get the request after `rq' in sector-sorted order
- */
-static inline struct request *
-deadline_latter_request(struct request *rq)
-{
-	struct rb_node *node = rb_next(&rq->rb_node);
-
-	if (node)
-		return rb_entry_rq(node);
-
-	return NULL;
-}
-
-static void
-deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
-{
-	struct rb_root *root = deadline_rb_root(dd, rq);
-
-	elv_rb_add(root, rq);
-}
-
-static inline void
-deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
-{
-	const int data_dir = rq_data_dir(rq);
-
-	if (dd->next_rq[data_dir] == rq)
-		dd->next_rq[data_dir] = deadline_latter_request(rq);
-
-	elv_rb_del(deadline_rb_root(dd, rq), rq);
-}
-
-/*
- * add rq to rbtree and fifo
- */
-static void
-deadline_add_request(struct request_queue *q, struct request *rq)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	const int data_dir = rq_data_dir(rq);
-
-	/*
-	 * This may be a requeue of a write request that has locked its
-	 * target zone. If it is the case, this releases the zone lock.
-	 */
-	blk_req_zone_write_unlock(rq);
-
-	deadline_add_rq_rb(dd, rq);
-
-	/*
-	 * set expire time and add to fifo list
-	 */
-	rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
-	list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
-}
-
-/*
- * remove rq from rbtree and fifo.
- */
-static void deadline_remove_request(struct request_queue *q, struct request *rq)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-
-	rq_fifo_clear(rq);
-	deadline_del_rq_rb(dd, rq);
-}
-
-static enum elv_merge
-deadline_merge(struct request_queue *q, struct request **req, struct bio *bio)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct request *__rq;
-
-	/*
-	 * check for front merge
-	 */
-	if (dd->front_merges) {
-		sector_t sector = bio_end_sector(bio);
-
-		__rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector);
-		if (__rq) {
-			BUG_ON(sector != blk_rq_pos(__rq));
-
-			if (elv_bio_merge_ok(__rq, bio)) {
-				*req = __rq;
-				return ELEVATOR_FRONT_MERGE;
-			}
-		}
-	}
-
-	return ELEVATOR_NO_MERGE;
-}
-
-static void deadline_merged_request(struct request_queue *q,
-				    struct request *req, enum elv_merge type)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-
-	/*
-	 * if the merge was a front merge, we need to reposition request
-	 */
-	if (type == ELEVATOR_FRONT_MERGE) {
-		elv_rb_del(deadline_rb_root(dd, req), req);
-		deadline_add_rq_rb(dd, req);
-	}
-}
-
-static void
-deadline_merged_requests(struct request_queue *q, struct request *req,
-			 struct request *next)
-{
-	/*
-	 * if next expires before rq, assign its expire time to rq
-	 * and move into next position (next will be deleted) in fifo
-	 */
-	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
-		if (time_before((unsigned long)next->fifo_time,
-				(unsigned long)req->fifo_time)) {
-			list_move(&req->queuelist, &next->queuelist);
-			req->fifo_time = next->fifo_time;
-		}
-	}
-
-	/*
-	 * kill knowledge of next, this one is a goner
-	 */
-	deadline_remove_request(q, next);
-}
-
-/*
- * move request from sort list to dispatch queue.
- */
-static inline void
-deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
-{
-	struct request_queue *q = rq->q;
-
-	/*
-	 * For a zoned block device, write requests must write lock their
-	 * target zone.
-	 */
-	blk_req_zone_write_lock(rq);
-
-	deadline_remove_request(q, rq);
-	elv_dispatch_add_tail(q, rq);
-}
-
-/*
- * move an entry to dispatch queue
- */
-static void
-deadline_move_request(struct deadline_data *dd, struct request *rq)
-{
-	const int data_dir = rq_data_dir(rq);
-
-	dd->next_rq[READ] = NULL;
-	dd->next_rq[WRITE] = NULL;
-	dd->next_rq[data_dir] = deadline_latter_request(rq);
-
-	/*
-	 * take it off the sort and fifo list, move
-	 * to dispatch queue
-	 */
-	deadline_move_to_dispatch(dd, rq);
-}
-
-/*
- * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
- * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
- */
-static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
-{
-	struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);
-
-	/*
-	 * rq is expired!
-	 */
-	if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
-		return 1;
-
-	return 0;
-}
-
-/*
- * For the specified data direction, return the next request to dispatch using
- * arrival ordered lists.
- */
-static struct request *
-deadline_fifo_request(struct deadline_data *dd, int data_dir)
-{
-	struct request *rq;
-
-	if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
-		return NULL;
-
-	if (list_empty(&dd->fifo_list[data_dir]))
-		return NULL;
-
-	rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
-	if (data_dir == READ || !blk_queue_is_zoned(rq->q))
-		return rq;
-
-	/*
-	 * Look for a write request that can be dispatched, that is one with
-	 * an unlocked target zone.
-	 */
-	list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) {
-		if (blk_req_can_dispatch_to_zone(rq))
-			return rq;
-	}
-
-	return NULL;
-}
-
-/*
- * For the specified data direction, return the next request to dispatch using
- * sector position sorted lists.
- */
-static struct request *
-deadline_next_request(struct deadline_data *dd, int data_dir)
-{
-	struct request *rq;
-
-	if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
-		return NULL;
-
-	rq = dd->next_rq[data_dir];
-	if (!rq)
-		return NULL;
-
-	if (data_dir == READ || !blk_queue_is_zoned(rq->q))
-		return rq;
-
-	/*
-	 * Look for a write request that can be dispatched, that is one with
-	 * an unlocked target zone.
-	 */
-	while (rq) {
-		if (blk_req_can_dispatch_to_zone(rq))
-			return rq;
-		rq = deadline_latter_request(rq);
-	}
-
-	return NULL;
-}
-
-/*
- * deadline_dispatch_requests selects the best request according to
- * read/write expire, fifo_batch, etc
- */
-static int deadline_dispatch_requests(struct request_queue *q, int force)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	const int reads = !list_empty(&dd->fifo_list[READ]);
-	const int writes = !list_empty(&dd->fifo_list[WRITE]);
-	struct request *rq, *next_rq;
-	int data_dir;
-
-	/*
-	 * batches are currently reads XOR writes
-	 */
-	rq = deadline_next_request(dd, WRITE);
-	if (!rq)
-		rq = deadline_next_request(dd, READ);
-
-	if (rq && dd->batching < dd->fifo_batch)
-		/* we have a next request are still entitled to batch */
-		goto dispatch_request;
-
-	/*
-	 * at this point we are not running a batch. select the appropriate
-	 * data direction (read / write)
-	 */
-
-	if (reads) {
-		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
-
-		if (deadline_fifo_request(dd, WRITE) &&
-		    (dd->starved++ >= dd->writes_starved))
-			goto dispatch_writes;
-
-		data_dir = READ;
-
-		goto dispatch_find_request;
-	}
-
-	/*
-	 * there are either no reads or writes have been starved
-	 */
-
-	if (writes) {
-dispatch_writes:
-		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));
-
-		dd->starved = 0;
-
-		data_dir = WRITE;
-
-		goto dispatch_find_request;
-	}
-
-	return 0;
-
-dispatch_find_request:
-	/*
-	 * we are not running a batch, find best request for selected data_dir
-	 */
-	next_rq = deadline_next_request(dd, data_dir);
-	if (deadline_check_fifo(dd, data_dir) || !next_rq) {
-		/*
-		 * A deadline has expired, the last request was in the other
-		 * direction, or we have run out of higher-sectored requests.
-		 * Start again from the request with the earliest expiry time.
-		 */
-		rq = deadline_fifo_request(dd, data_dir);
-	} else {
-		/*
-		 * The last req was the same dir and we have a next request in
-		 * sort order. No expired requests so continue on from here.
-		 */
-		rq = next_rq;
-	}
-
-	/*
-	 * For a zoned block device, if we only have writes queued and none of
-	 * them can be dispatched, rq will be NULL.
-	 */
-	if (!rq)
-		return 0;
-
-	dd->batching = 0;
-
-dispatch_request:
-	/*
-	 * rq is the selected appropriate request.
-	 */
-	dd->batching++;
-	deadline_move_request(dd, rq);
-
-	return 1;
-}
-
-/*
- * For zoned block devices, write unlock the target zone of completed
- * write requests.
- */
-static void
-deadline_completed_request(struct request_queue *q, struct request *rq)
-{
-	blk_req_zone_write_unlock(rq);
-}
-
-static void deadline_exit_queue(struct elevator_queue *e)
-{
-	struct deadline_data *dd = e->elevator_data;
-
-	BUG_ON(!list_empty(&dd->fifo_list[READ]));
-	BUG_ON(!list_empty(&dd->fifo_list[WRITE]));
-
-	kfree(dd);
-}
-
-/*
- * initialize elevator private data (deadline_data).
- */
-static int deadline_init_queue(struct request_queue *q, struct elevator_type *e)
-{
-	struct deadline_data *dd;
-	struct elevator_queue *eq;
-
-	eq = elevator_alloc(q, e);
-	if (!eq)
-		return -ENOMEM;
-
-	dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
-	if (!dd) {
-		kobject_put(&eq->kobj);
-		return -ENOMEM;
-	}
-	eq->elevator_data = dd;
-
-	INIT_LIST_HEAD(&dd->fifo_list[READ]);
-	INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
-	dd->sort_list[READ] = RB_ROOT;
-	dd->sort_list[WRITE] = RB_ROOT;
-	dd->fifo_expire[READ] = read_expire;
-	dd->fifo_expire[WRITE] = write_expire;
-	dd->writes_starved = writes_starved;
-	dd->front_merges = 1;
-	dd->fifo_batch = fifo_batch;
-
-	spin_lock_irq(q->queue_lock);
-	q->elevator = eq;
-	spin_unlock_irq(q->queue_lock);
-	return 0;
-}
-
-/*
- * sysfs parts below
- */
-
-static ssize_t
-deadline_var_show(int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static void
-deadline_var_store(int *var, const char *page)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtol(p, &p, 10);
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
-static ssize_t __FUNC(struct elevator_queue *e, char *page)		\
-{									\
-	struct deadline_data *dd = e->elevator_data;			\
-	int __data = __VAR;						\
-	if (__CONV)							\
-		__data = jiffies_to_msecs(__data);			\
-	return deadline_var_show(__data, (page));			\
-}
-SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1);
-SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1);
-SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
-SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
-SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
-{									\
-	struct deadline_data *dd = e->elevator_data;			\
-	int __data;							\
-	deadline_var_store(&__data, (page));				\
-	if (__data < (MIN))						\
-		__data = (MIN);						\
-	else if (__data > (MAX))					\
-		__data = (MAX);						\
-	if (__CONV)							\
-		*(__PTR) = msecs_to_jiffies(__data);			\
-	else								\
-		*(__PTR) = __data;					\
-	return count;							\
-}
-STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
-STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
-STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
-#undef STORE_FUNCTION
-
-#define DD_ATTR(name) \
-	__ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)
-
-static struct elv_fs_entry deadline_attrs[] = {
-	DD_ATTR(read_expire),
-	DD_ATTR(write_expire),
-	DD_ATTR(writes_starved),
-	DD_ATTR(front_merges),
-	DD_ATTR(fifo_batch),
-	__ATTR_NULL
-};
-
-static struct elevator_type iosched_deadline = {
-	.ops.sq = {
-		.elevator_merge_fn = 		deadline_merge,
-		.elevator_merged_fn =		deadline_merged_request,
-		.elevator_merge_req_fn =	deadline_merged_requests,
-		.elevator_dispatch_fn =		deadline_dispatch_requests,
-		.elevator_completed_req_fn =	deadline_completed_request,
-		.elevator_add_req_fn =		deadline_add_request,
-		.elevator_former_req_fn =	elv_rb_former_request,
-		.elevator_latter_req_fn =	elv_rb_latter_request,
-		.elevator_init_fn =		deadline_init_queue,
-		.elevator_exit_fn =		deadline_exit_queue,
-	},
-
-	.elevator_attrs = deadline_attrs,
-	.elevator_name = "deadline",
-	.elevator_owner = THIS_MODULE,
-};
-
-static int __init deadline_init(void)
-{
-	return elv_register(&iosched_deadline);
-}
-
-static void __exit deadline_exit(void)
-{
-	elv_unregister(&iosched_deadline);
-}
-
-module_init(deadline_init);
-module_exit(deadline_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("deadline IO scheduler");
diff --git a/block/elevator.c b/block/elevator.c
index 8fdcd64ae12e..54e1adac26c5 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -225,8 +225,6 @@ int elevator_init(struct request_queue *q)
 							chosen_elevator);
 	}
 
-	if (!e)
-		e = elevator_get(q, CONFIG_DEFAULT_IOSCHED, false);
 	if (!e) {
 		printk(KERN_ERR
 			"Default I/O scheduler not found. Using noop.\n");
@@ -356,68 +354,6 @@ struct request *elv_rb_find(struct rb_root *root, sector_t sector)
 }
 EXPORT_SYMBOL(elv_rb_find);
 
-/*
- * Insert rq into dispatch queue of q.  Queue lock must be held on
- * entry.  rq is sort instead into the dispatch queue. To be used by
- * specific elevators.
- */
-void elv_dispatch_sort(struct request_queue *q, struct request *rq)
-{
-	sector_t boundary;
-	struct list_head *entry;
-
-	if (q->last_merge == rq)
-		q->last_merge = NULL;
-
-	elv_rqhash_del(q, rq);
-
-	q->nr_sorted--;
-
-	boundary = q->end_sector;
-	list_for_each_prev(entry, &q->queue_head) {
-		struct request *pos = list_entry_rq(entry);
-
-		if (req_op(rq) != req_op(pos))
-			break;
-		if (rq_data_dir(rq) != rq_data_dir(pos))
-			break;
-		if (pos->rq_flags & (RQF_STARTED | RQF_SOFTBARRIER))
-			break;
-		if (blk_rq_pos(rq) >= boundary) {
-			if (blk_rq_pos(pos) < boundary)
-				continue;
-		} else {
-			if (blk_rq_pos(pos) >= boundary)
-				break;
-		}
-		if (blk_rq_pos(rq) >= blk_rq_pos(pos))
-			break;
-	}
-
-	list_add(&rq->queuelist, entry);
-}
-EXPORT_SYMBOL(elv_dispatch_sort);
-
-/*
- * Insert rq into dispatch queue of q.  Queue lock must be held on
- * entry.  rq is added to the back of the dispatch queue. To be used by
- * specific elevators.
- */
-void elv_dispatch_add_tail(struct request_queue *q, struct request *rq)
-{
-	if (q->last_merge == rq)
-		q->last_merge = NULL;
-
-	elv_rqhash_del(q, rq);
-
-	q->nr_sorted--;
-
-	q->end_sector = rq_end_sector(rq);
-	q->boundary_rq = rq;
-	list_add_tail(&rq->queuelist, &q->queue_head);
-}
-EXPORT_SYMBOL(elv_dispatch_add_tail);
-
 enum elv_merge elv_merge(struct request_queue *q, struct request **req,
 		struct bio *bio)
 {
@@ -881,12 +817,6 @@ int elv_register(struct elevator_type *e)
 	list_add_tail(&e->list, &elv_list);
 	spin_unlock(&elv_list_lock);
 
-	/* print pretty message */
-	if (elevator_match(e, chosen_elevator) ||
-			(!*chosen_elevator &&
-			 elevator_match(e, CONFIG_DEFAULT_IOSCHED)))
-				def = " (default)";
-
 	printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
 								def);
 	return 0;
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
deleted file mode 100644
index 2d1b15d89b45..000000000000
--- a/block/noop-iosched.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * elevator noop
- */
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-
-struct noop_data {
-	struct list_head queue;
-};
-
-static void noop_merged_requests(struct request_queue *q, struct request *rq,
-				 struct request *next)
-{
-	list_del_init(&next->queuelist);
-}
-
-static int noop_dispatch(struct request_queue *q, int force)
-{
-	struct noop_data *nd = q->elevator->elevator_data;
-	struct request *rq;
-
-	rq = list_first_entry_or_null(&nd->queue, struct request, queuelist);
-	if (rq) {
-		list_del_init(&rq->queuelist);
-		elv_dispatch_sort(q, rq);
-		return 1;
-	}
-	return 0;
-}
-
-static void noop_add_request(struct request_queue *q, struct request *rq)
-{
-	struct noop_data *nd = q->elevator->elevator_data;
-
-	list_add_tail(&rq->queuelist, &nd->queue);
-}
-
-static struct request *
-noop_former_request(struct request_queue *q, struct request *rq)
-{
-	struct noop_data *nd = q->elevator->elevator_data;
-
-	if (rq->queuelist.prev == &nd->queue)
-		return NULL;
-	return list_prev_entry(rq, queuelist);
-}
-
-static struct request *
-noop_latter_request(struct request_queue *q, struct request *rq)
-{
-	struct noop_data *nd = q->elevator->elevator_data;
-
-	if (rq->queuelist.next == &nd->queue)
-		return NULL;
-	return list_next_entry(rq, queuelist);
-}
-
-static int noop_init_queue(struct request_queue *q, struct elevator_type *e)
-{
-	struct noop_data *nd;
-	struct elevator_queue *eq;
-
-	eq = elevator_alloc(q, e);
-	if (!eq)
-		return -ENOMEM;
-
-	nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
-	if (!nd) {
-		kobject_put(&eq->kobj);
-		return -ENOMEM;
-	}
-	eq->elevator_data = nd;
-
-	INIT_LIST_HEAD(&nd->queue);
-
-	spin_lock_irq(q->queue_lock);
-	q->elevator = eq;
-	spin_unlock_irq(q->queue_lock);
-	return 0;
-}
-
-static void noop_exit_queue(struct elevator_queue *e)
-{
-	struct noop_data *nd = e->elevator_data;
-
-	BUG_ON(!list_empty(&nd->queue));
-	kfree(nd);
-}
-
-static struct elevator_type elevator_noop = {
-	.ops.sq = {
-		.elevator_merge_req_fn		= noop_merged_requests,
-		.elevator_dispatch_fn		= noop_dispatch,
-		.elevator_add_req_fn		= noop_add_request,
-		.elevator_former_req_fn		= noop_former_request,
-		.elevator_latter_req_fn		= noop_latter_request,
-		.elevator_init_fn		= noop_init_queue,
-		.elevator_exit_fn		= noop_exit_queue,
-	},
-	.elevator_name = "noop",
-	.elevator_owner = THIS_MODULE,
-};
-
-static int __init noop_init(void)
-{
-	return elv_register(&elevator_noop);
-}
-
-static void __exit noop_exit(void)
-{
-	elv_unregister(&elevator_noop);
-}
-
-module_init(noop_init);
-module_exit(noop_exit);
-
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("No-op IO scheduler");