This patch changes cfq to use fair queuing code from elevator layer.

Signed-off-by: Nauman Rafique <nau...@google.com>
Signed-off-by: Fabio Checconi <fa...@gandalf.sssup.it>
Signed-off-by: Paolo Valente <paolo.vale...@unimore.it>
Signed-off-by: Gui Jianfeng <guijianf...@cn.fujitsu.com>
Signed-off-by: Vivek Goyal <vgo...@redhat.com>
Acked-by: Rik van Riel <r...@redhat.com>
---
 block/Kconfig.iosched |    3 +-
 block/cfq-iosched.c   |  981 +++++++++++--------------------------------------
 2 files changed, 218 insertions(+), 766 deletions(-)

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 3398134..dd5224d 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -3,7 +3,7 @@ if BLOCK
 menu "IO Schedulers"
 
 config ELV_FAIR_QUEUING
-       bool "Elevator Fair Queuing Support"
+       bool
        default n
        ---help---
          Traditionally only cfq had notion of multiple queues and it did
@@ -46,6 +46,7 @@ config IOSCHED_DEADLINE
 
 config IOSCHED_CFQ
        tristate "CFQ I/O scheduler"
+       select ELV_FAIR_QUEUING
        default y
        ---help---
          The CFQ I/O scheduler tries to distribute bandwidth equally
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 5a67ec0..3e24c03 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -12,6 +12,7 @@
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/blktrace_api.h>
+#include "elevator-fq.h"
 
 /*
  * tunables
@@ -23,17 +24,10 @@ static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
 static const int cfq_back_max = 16 * 1024;
 /* penalty of a backwards seek */
 static const int cfq_back_penalty = 2;
-static const int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
 static const int cfq_slice_async_rq = 2;
 static int cfq_slice_idle = HZ / 125;
 
 /*
- * offset from end of service tree
- */
-#define CFQ_IDLE_DELAY         (HZ / 5)
-
-/*
  * below this threshold, we consider thinktime immediate
  */
 #define CFQ_MIN_TT             (2)
@@ -43,7 +37,7 @@ static int cfq_slice_idle = HZ / 125;
 
 #define RQ_CIC(rq)             \
        ((struct cfq_io_context *) (rq)->elevator_private)
-#define RQ_CFQQ(rq)            (struct cfq_queue *) ((rq)->elevator_private2)
+#define RQ_CFQQ(rq)    (struct cfq_queue *) (elv_ioq_sched_queue((rq)->ioq))
 
 static struct kmem_cache *cfq_pool;
 static struct kmem_cache *cfq_ioc_pool;
@@ -53,8 +47,6 @@ static struct completion *ioc_gone;
 static DEFINE_SPINLOCK(ioc_gone_lock);
 
 #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)
 
@@ -74,16 +66,11 @@ struct cfq_rb_root {
  * Per process-grouping structure
  */
 struct cfq_queue {
-       /* reference count */
-       atomic_t ref;
+       struct io_queue *ioq;
        /* 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 */
-       unsigned long rb_key;
        /* prio tree member */
        struct rb_node p_node;
        /* prio tree root we belong to, if any */
@@ -99,18 +86,13 @@ struct cfq_queue {
        /* fifo list of requests in sort_list */
        struct list_head fifo;
 
-       unsigned long slice_end;
-       long slice_resid;
        unsigned int slice_dispatch;
 
        /* pending metadata requests */
        int meta_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;
+       unsigned short org_ioprio, org_ioprio_class;
 
        pid_t pid;
 };
@@ -120,12 +102,6 @@ struct cfq_queue {
  */
 struct cfq_data {
        struct request_queue *queue;
-
-       /*
-        * rr list of queues with requests and the count of them
-        */
-       struct cfq_rb_root service_tree;
-
        /*
         * Each priority tree is sorted by next_request position.  These
         * trees are used when determining if two or more queues are
@@ -133,14 +109,6 @@ struct cfq_data {
         */
        struct rb_root prio_trees[CFQ_PRIO_LISTS];
 
-       unsigned int busy_queues;
-       /*
-        * Used to track any pending rt requests so we can pre-empt current
-        * non-RT cfqq in service when this value is non-zero.
-        */
-       unsigned int busy_rt_queues;
-
-       int rq_in_driver;
        int sync_flight;
 
        /*
@@ -151,21 +119,8 @@ struct cfq_data {
        int hw_tag_samples;
        int rq_in_driver_peak;
 
-       /*
-        * idle window management
-        */
-       struct timer_list idle_slice_timer;
-       struct work_struct unplug_work;
-
-       struct cfq_queue *active_queue;
        struct cfq_io_context *active_cic;
 
-       /*
-        * async queue for each priority case
-        */
-       struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
-       struct cfq_queue *async_idle_cfqq;
-
        sector_t last_position;
 
        /*
@@ -175,7 +130,6 @@ struct cfq_data {
        unsigned int cfq_fifo_expire[2];
        unsigned int cfq_back_penalty;
        unsigned int cfq_back_max;
-       unsigned int cfq_slice[2];
        unsigned int cfq_slice_async_rq;
        unsigned int cfq_slice_idle;
 
@@ -188,16 +142,10 @@ struct cfq_data {
 };
 
 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,       /* must be allowed rq alloc */
        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,             /* has done a coop jump of the queue */
 };
 
@@ -215,16 +163,10 @@ 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);
 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);
 #undef CFQ_CFQQ_FNS
 
@@ -263,66 +205,27 @@ static inline int cfq_bio_sync(struct bio *bio)
        return 0;
 }
 
-/*
- * 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)
+static inline struct io_group *cfqq_to_io_group(struct cfq_queue *cfqq)
 {
-       if (cfqd->busy_queues) {
-               cfq_log(cfqd, "schedule dispatch");
-               kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
-       }
+       return ioq_to_io_group(cfqq->ioq);
 }
 
-static int cfq_queue_empty(struct request_queue *q)
+static inline int cfq_class_idle(struct cfq_queue *cfqq)
 {
-       struct cfq_data *cfqd = q->elevator->elevator_data;
-
-       return !cfqd->busy_queues;
+       return elv_ioq_class_idle(cfqq->ioq);
 }
 
-/*
- * 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 int cfq_prio_slice(struct cfq_data *cfqd, int sync,
-                                unsigned short prio)
+static inline int cfq_cfqq_sync(struct cfq_queue *cfqq)
 {
-       const int base_slice = cfqd->cfq_slice[sync];
-
-       WARN_ON(prio >= IOPRIO_BE_NR);
-
-       return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
+       return elv_ioq_sync(cfqq->ioq);
 }
 
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfqq_is_active_queue(struct cfq_queue *cfqq)
 {
-       return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-       cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
-       cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
-}
-
-/*
- * 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 int cfq_slice_used(struct cfq_queue *cfqq)
-{
-       if (cfq_cfqq_slice_new(cfqq))
-               return 0;
-       if (time_before(jiffies, cfqq->slice_end))
-               return 0;
+       struct cfq_data *cfqd = cfqq->cfqd;
+       struct elevator_queue *e = cfqd->queue->elevator;
 
-       return 1;
+       return (elv_active_sched_queue(e) == cfqq);
 }
 
 /*
@@ -421,33 +324,6 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, 
struct request *rq2)
 }
 
 /*
- * The below is leftmost cache rbtree addon
- */
-static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
-{
-       if (!root->left)
-               root->left = rb_first(&root->rb);
-
-       if (root->left)
-               return rb_entry(root->left, struct cfq_queue, rb_node);
-
-       return NULL;
-}
-
-static void rb_erase_init(struct rb_node *n, struct rb_root *root)
-{
-       rb_erase(n, root);
-       RB_CLEAR_NODE(n);
-}
-
-static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
-{
-       if (root->left == n)
-               root->left = NULL;
-       rb_erase_init(n, &root->rb);
-}
-
-/*
  * would be nice to take fifo expire time into account as well
  */
 static struct request *
@@ -474,95 +350,6 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue 
*cfqq,
        return cfq_choose_req(cfqd, next, prev);
 }
 
-static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
-                                     struct cfq_queue *cfqq)
-{
-       /*
-        * just an approximation, should be ok.
-        */
-       return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
-                      cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
-}
-
-/*
- * The cfqd->service_tree 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,
-                                int add_front)
-{
-       struct rb_node **p, *parent;
-       struct cfq_queue *__cfqq;
-       unsigned long rb_key;
-       int left;
-
-       if (cfq_class_idle(cfqq)) {
-               rb_key = CFQ_IDLE_DELAY;
-               parent = rb_last(&cfqd->service_tree.rb);
-               if (parent && parent != &cfqq->rb_node) {
-                       __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-                       rb_key += __cfqq->rb_key;
-               } else
-                       rb_key += jiffies;
-       } else if (!add_front) {
-               rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
-               rb_key += cfqq->slice_resid;
-               cfqq->slice_resid = 0;
-       } else
-               rb_key = 0;
-
-       if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
-               /*
-                * same position, nothing more to do
-                */
-               if (rb_key == cfqq->rb_key)
-                       return;
-
-               cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
-       }
-
-       left = 1;
-       parent = NULL;
-       p = &cfqd->service_tree.rb.rb_node;
-       while (*p) {
-               struct rb_node **n;
-
-               parent = *p;
-               __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-
-               /*
-                * sort RT queues first, we always want to give
-                * preference to them. IDLE queues goes to the back.
-                * after that, sort on the next service time.
-                */
-               if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
-                       n = &(*p)->rb_left;
-               else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
-                       n = &(*p)->rb_right;
-               else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
-                       n = &(*p)->rb_left;
-               else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
-                       n = &(*p)->rb_right;
-               else if (rb_key < __cfqq->rb_key)
-                       n = &(*p)->rb_left;
-               else
-                       n = &(*p)->rb_right;
-
-               if (n == &(*p)->rb_right)
-                       left = 0;
-
-               p = n;
-       }
-
-       if (left)
-               cfqd->service_tree.left = &cfqq->rb_node;
-
-       cfqq->rb_key = rb_key;
-       rb_link_node(&cfqq->rb_node, parent, p);
-       rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
-}
-
 static struct cfq_queue *
 cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
                     sector_t sector, struct rb_node **ret_parent,
@@ -624,57 +411,43 @@ static void cfq_prio_tree_add(struct cfq_data *cfqd, 
struct cfq_queue *cfqq)
                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)
+/* An active ioq is being reset. A chance to do cic related stuff. */
+static void cfq_active_ioq_reset(struct request_queue *q, void *sched_queue)
 {
-       /*
-        * 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);
-       }
-}
+       struct cfq_data *cfqd = q->elevator->elevator_data;
+       struct cfq_queue *cfqq = sched_queue;
 
-/*
- * 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_class_rt(cfqq))
-               cfqd->busy_rt_queues++;
+       if (cfqd->active_cic) {
+               put_io_context(cfqd->active_cic->ioc);
+               cfqd->active_cic = NULL;
+       }
 
-       cfq_resort_rr_list(cfqd, cfqq);
+       /* Resort the cfqq in prio tree */
+       if (cfqq)
+               cfq_prio_tree_add(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)
+/* An ioq has been set as active one. */
+static void cfq_active_ioq_set(struct request_queue *q, void *sched_queue,
+                               int coop)
 {
-       cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
-       BUG_ON(!cfq_cfqq_on_rr(cfqq));
-       cfq_clear_cfqq_on_rr(cfqq);
+       struct cfq_queue *cfqq = sched_queue;
 
-       if (!RB_EMPTY_NODE(&cfqq->rb_node))
-               cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
-       if (cfqq->p_root) {
-               rb_erase(&cfqq->p_node, cfqq->p_root);
-               cfqq->p_root = NULL;
-       }
+       cfqq->slice_dispatch = 0;
+
+       cfq_clear_cfqq_must_alloc_slice(cfqq);
+       cfq_clear_cfqq_fifo_expire(cfqq);
 
-       BUG_ON(!cfqd->busy_queues);
-       cfqd->busy_queues--;
-       if (cfq_class_rt(cfqq))
-               cfqd->busy_rt_queues--;
+       /*
+        * If queue was selected because it was a close cooperator, then
+        * mark it so that it is not selected again and again. Otherwise
+        * clear the coop flag so that it becomes eligible to get selected
+        * again.
+        */
+       if (coop)
+               cfq_mark_cfqq_coop(cfqq);
+       else
+               cfq_clear_cfqq_coop(cfqq);
 }
 
 /*
@@ -683,7 +456,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct 
cfq_queue *cfqq)
 static void cfq_del_rq_rb(struct request *rq)
 {
        struct cfq_queue *cfqq = RQ_CFQQ(rq);
-       struct cfq_data *cfqd = cfqq->cfqd;
        const int sync = rq_is_sync(rq);
 
        BUG_ON(!cfqq->queued[sync]);
@@ -691,8 +463,17 @@ static void cfq_del_rq_rb(struct request *rq)
 
        elv_rb_del(&cfqq->sort_list, rq);
 
-       if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
-               cfq_del_cfqq_rr(cfqd, cfqq);
+       /*
+        * If this was last request in the queue, remove this queue from
+        * prio trees. For last request nr_queued count will still be 1 as
+        * elevator fair queuing layer is yet to do the accounting.
+        */
+       if (elv_ioq_nr_queued(cfqq->ioq) == 1) {
+               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)
@@ -710,9 +491,6 @@ static void cfq_add_rq_rb(struct request *rq)
        while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
                cfq_dispatch_insert(cfqd->queue, __alias);
 
-       if (!cfq_cfqq_on_rr(cfqq))
-               cfq_add_cfqq_rr(cfqd, cfqq);
-
        /*
         * check if this request is a better next-serve candidate
         */
@@ -720,7 +498,9 @@ static void cfq_add_rq_rb(struct request *rq)
        cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
 
        /*
-        * adjust priority tree position, if ->next_rq changes
+        * adjust priority tree position, if ->next_rq changes. This should
+        * also take care of adding a new queue to prio tree as if this is
+        * first request then prev would be null and cfqq->next_rq will not.
         */
        if (prev != cfqq->next_rq)
                cfq_prio_tree_add(cfqd, cfqq);
@@ -760,23 +540,9 @@ 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);
@@ -861,93 +627,21 @@ static int cfq_allow_merge(struct request_queue *q, 
struct request *rq,
        return 0;
 }
 
-static void __cfq_set_active_queue(struct cfq_data *cfqd,
-                                  struct cfq_queue *cfqq)
-{
-       if (cfqq) {
-               cfq_log_cfqq(cfqd, cfqq, "set_active");
-               cfqq->slice_end = 0;
-               cfqq->slice_dispatch = 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);
-
-               del_timer(&cfqd->idle_slice_timer);
-       }
-
-       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,
-                   int timed_out)
+__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-       cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
-
-       if (cfq_cfqq_wait_request(cfqq))
-               del_timer(&cfqd->idle_slice_timer);
-
-       cfq_clear_cfqq_wait_request(cfqq);
-
-       /*
-        * store what was left of this slice, if the queue idled/timed out
-        */
-       if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
-               cfqq->slice_resid = cfqq->slice_end - jiffies;
-               cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
-       }
-
-       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->ioc);
-               cfqd->active_cic = NULL;
-       }
+       elv_ioq_slice_expired(cfqd->queue, cfqq->ioq);
 }
 
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
+static inline void cfq_slice_expired(struct cfq_data *cfqd)
 {
-       struct cfq_queue *cfqq = cfqd->active_queue;
+       struct cfq_queue *cfqq = elv_active_sched_queue(cfqd->queue->elevator);
 
        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)
-{
-       if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
-               return NULL;
-
-       return cfq_rb_first(&cfqd->service_tree);
-}
-
-/*
- * 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);
-               if (cfqq)
-                       cfq_clear_cfqq_coop(cfqq);
-       }
-
-       __cfq_set_active_queue(cfqd, cfqq);
-       return cfqq;
+               __cfq_slice_expired(cfqd, cfqq);
 }
 
 static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
@@ -1024,11 +718,11 @@ static struct cfq_queue *cfqq_close(struct cfq_data 
*cfqd,
  * 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,
-                                             int probe)
+static struct io_queue *cfq_close_cooperator(struct request_queue *q,
+                                             void *cur_sched_queue)
 {
-       struct cfq_queue *cfqq;
+       struct cfq_queue *cur_cfqq = cur_sched_queue, *cfqq;
+       struct cfq_data *cfqd = q->elevator->elevator_data;
 
        /*
         * A valid cfq_io_context is necessary to compare requests against
@@ -1049,14 +743,13 @@ static struct cfq_queue *cfq_close_cooperator(struct 
cfq_data *cfqd,
        if (cfq_cfqq_coop(cfqq))
                return NULL;
 
-       if (!probe)
-               cfq_mark_cfqq_coop(cfqq);
-       return cfqq;
+       return cfqq->ioq;
 }
 
-static void cfq_arm_slice_timer(struct cfq_data *cfqd)
+static void cfq_arm_slice_timer(struct request_queue *q, void *sched_queue)
 {
-       struct cfq_queue *cfqq = cfqd->active_queue;
+       struct cfq_data *cfqd = q->elevator->elevator_data;
+       struct cfq_queue *cfqq = sched_queue;
        struct cfq_io_context *cic;
        unsigned long sl;
 
@@ -1069,18 +762,18 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
                return;
 
        WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
-       WARN_ON(cfq_cfqq_slice_new(cfqq));
+       WARN_ON(elv_ioq_slice_new(cfqq->ioq));
 
        /*
         * idle is disabled, either manually or by past process history
         */
-       if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
+       if (!cfqd->cfq_slice_idle || !elv_ioq_idle_window(cfqq->ioq))
                return;
 
        /*
         * still requests with the driver, don't idle
         */
-       if (cfqd->rq_in_driver)
+       if (elv_rq_in_driver(q->elevator))
                return;
 
        /*
@@ -1090,7 +783,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
        if (!cic || !atomic_read(&cic->ioc->nr_tasks))
                return;
 
-       cfq_mark_cfqq_wait_request(cfqq);
+       elv_mark_ioq_wait_request(cfqq->ioq);
 
        /*
         * we don't want to idle for seeks, but we do want to allow
@@ -1101,7 +794,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
        if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
                sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
 
-       mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
+       elv_mod_idle_slice_timer(q->elevator, jiffies + sl);
        cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
 }
 
@@ -1113,10 +806,9 @@ 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");
+       cfq_log_cfqq(cfqd, cfqq, "dispatch_insert sect=%d", blk_rq_sectors(rq));
 
        cfq_remove_request(rq);
-       cfqq->dispatched++;
        elv_dispatch_sort(q, rq);
 
        if (cfq_cfqq_sync(cfqq))
@@ -1154,78 +846,11 @@ static inline int
 cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
        const int base_rq = cfqd->cfq_slice_async_rq;
+       unsigned short ioprio = elv_ioq_ioprio(cfqq->ioq);
 
-       WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+       WARN_ON(ioprio >= IOPRIO_BE_NR);
 
-       return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
-}
-
-/*
- * 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;
-
-       cfqq = cfqd->active_queue;
-       if (!cfqq)
-               goto new_queue;
-
-       /*
-        * The active queue has run out of time, expire it and select new.
-        */
-       if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
-               goto expire;
-
-       /*
-        * If we have a RT cfqq waiting, then we pre-empt the current non-rt
-        * cfqq.
-        */
-       if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
-               /*
-                * We simulate this as cfqq timed out so that it gets to bank
-                * the remaining of its time slice.
-                */
-               cfq_log_cfqq(cfqd, cfqq, "preempt");
-               cfq_slice_expired(cfqd, 1);
-               goto new_queue;
-       }
-
-       /*
-        * 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.
-        */
-       new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
-       if (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 (timer_pending(&cfqd->idle_slice_timer) ||
-           (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
-               cfqq = NULL;
-               goto keep_queue;
-       }
-
-expire:
-       cfq_slice_expired(cfqd, 0);
-new_queue:
-       cfqq = cfq_set_active_queue(cfqd, new_cfqq);
-keep_queue:
-       return cfqq;
+       return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - ioprio));
 }
 
 static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
@@ -1250,12 +875,14 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
        struct cfq_queue *cfqq;
        int dispatched = 0;
 
-       while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL)
+       while ((cfqq = elv_select_sched_queue(cfqd->queue, 1)) != NULL)
                dispatched += __cfq_forced_dispatch_cfqq(cfqq);
 
-       cfq_slice_expired(cfqd, 0);
+       /* This probably is redundant now. above loop will should make sure
+        * that all the busy queues have expired */
+       cfq_slice_expired(cfqd);
 
-       BUG_ON(cfqd->busy_queues);
+       BUG_ON(elv_nr_busy_ioq(cfqd->queue->elevator));
 
        cfq_log(cfqd, "forced_dispatch=%d", dispatched);
        return dispatched;
@@ -1301,13 +928,10 @@ static int cfq_dispatch_requests(struct request_queue 
*q, int force)
        struct cfq_queue *cfqq;
        unsigned int max_dispatch;
 
-       if (!cfqd->busy_queues)
-               return 0;
-
        if (unlikely(force))
                return cfq_forced_dispatch(cfqd);
 
-       cfqq = cfq_select_queue(cfqd);
+       cfqq = elv_select_sched_queue(q, 0);
        if (!cfqq)
                return 0;
 
@@ -1324,7 +948,7 @@ static int cfq_dispatch_requests(struct request_queue *q, 
int force)
        /*
         * Does this cfqq already have too much IO in flight?
         */
-       if (cfqq->dispatched >= max_dispatch) {
+       if (elv_ioq_nr_dispatched(cfqq->ioq) >= max_dispatch) {
                /*
                 * idle queue must always only have a single IO in flight
                 */
@@ -1334,13 +958,13 @@ static int cfq_dispatch_requests(struct request_queue 
*q, int force)
                /*
                 * We have other queues, don't allow more IO from this one
                 */
-               if (cfqd->busy_queues > 1)
+               if (elv_nr_busy_ioq(q->elevator) > 1)
                        return 0;
 
                /*
                 * we are the only queue, allow up to 4 times of 'quantum'
                 */
-               if (cfqq->dispatched >= 4 * max_dispatch)
+               if (elv_ioq_nr_dispatched(cfqq->ioq) >= 4 * max_dispatch)
                        return 0;
        }
 
@@ -1349,51 +973,45 @@ static int cfq_dispatch_requests(struct request_queue 
*q, int force)
         */
        cfq_dispatch_request(cfqd, cfqq);
        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) &&
+       if (elv_nr_busy_ioq(q->elevator) > 1 && ((!cfq_cfqq_sync(cfqq) &&
            cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
            cfq_class_idle(cfqq))) {
-               cfqq->slice_end = jiffies + 1;
-               cfq_slice_expired(cfqd, 0);
+               cfq_slice_expired(cfqd);
        }
 
        cfq_log(cfqd, "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.
- *
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
+static void cfq_free_cfq_queue(struct elevator_queue *e, void *sched_queue)
 {
+       struct cfq_queue *cfqq = sched_queue;
        struct cfq_data *cfqd = cfqq->cfqd;
 
-       BUG_ON(atomic_read(&cfqq->ref) <= 0);
-
-       if (!atomic_dec_and_test(&cfqq->ref))
-               return;
+       BUG_ON(!cfqq);
 
-       cfq_log_cfqq(cfqd, cfqq, "put_queue");
+       cfq_log_cfqq(cfqd, cfqq, "free_queue");
        BUG_ON(rb_first(&cfqq->sort_list));
        BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
-       BUG_ON(cfq_cfqq_on_rr(cfqq));
 
-       if (unlikely(cfqd->active_queue == cfqq)) {
-               __cfq_slice_expired(cfqd, cfqq, 0);
-               cfq_schedule_dispatch(cfqd);
+       if (unlikely(cfqq_is_active_queue(cfqq))) {
+               __cfq_slice_expired(cfqd, cfqq);
+               elv_schedule_dispatch(cfqd->queue);
        }
 
        kmem_cache_free(cfq_pool, cfqq);
 }
 
+static inline void cfq_put_queue(struct cfq_queue *cfqq)
+{
+       elv_put_ioq(cfqq->ioq);
+}
+
 /*
  * Must always be called with the rcu_read_lock() held
  */
@@ -1481,11 +1099,12 @@ static void cfq_free_io_context(struct io_context *ioc)
 
 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);
+       if (unlikely(cfqq == elv_active_sched_queue(cfqd->queue->elevator))) {
+               __cfq_slice_expired(cfqd, cfqq);
+               elv_schedule_dispatch(cfqd->queue);
        }
 
+       elv_exit_ioq(cfqq->ioq);
        cfq_put_queue(cfqq);
 }
 
@@ -1571,7 +1190,7 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t 
gfp_mask)
 static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 {
        struct task_struct *tsk = current;
-       int ioprio_class;
+       int ioprio_class, ioprio;
 
        if (!cfq_cfqq_prio_changed(cfqq))
                return;
@@ -1584,30 +1203,33 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, 
struct io_context *ioc)
                /*
                 * no prio set, inherit CPU scheduling settings
                 */
-               cfqq->ioprio = task_nice_ioprio(tsk);
-               cfqq->ioprio_class = task_nice_ioclass(tsk);
+               ioprio = task_nice_ioprio(tsk);
+               ioprio_class = task_nice_ioclass(tsk);
                break;
        case IOPRIO_CLASS_RT:
-               cfqq->ioprio = task_ioprio(ioc);
-               cfqq->ioprio_class = IOPRIO_CLASS_RT;
+               ioprio = task_ioprio(ioc);
+               ioprio_class = IOPRIO_CLASS_RT;
                break;
        case IOPRIO_CLASS_BE:
-               cfqq->ioprio = task_ioprio(ioc);
-               cfqq->ioprio_class = IOPRIO_CLASS_BE;
+               ioprio = task_ioprio(ioc);
+               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);
+               ioprio_class = IOPRIO_CLASS_IDLE;
+               ioprio = 7;
+               elv_clear_ioq_idle_window(cfqq->ioq);
                break;
        }
 
+       elv_ioq_set_ioprio_class(cfqq->ioq, ioprio_class);
+       elv_ioq_set_ioprio(cfqq->ioq, ioprio);
+
        /*
         * 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;
+       cfqq->org_ioprio = ioprio;
+       cfqq->org_ioprio_class = ioprio_class;
        cfq_clear_cfqq_prio_changed(cfqq);
 }
 
@@ -1649,19 +1271,17 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
 static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                          pid_t pid, int is_sync)
 {
-       RB_CLEAR_NODE(&cfqq->rb_node);
        RB_CLEAR_NODE(&cfqq->p_node);
        INIT_LIST_HEAD(&cfqq->fifo);
 
-       atomic_set(&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);
+                       elv_mark_ioq_idle_window(cfqq->ioq);
+               elv_mark_ioq_sync(cfqq->ioq);
        }
        cfqq->pid = pid;
 }
@@ -1672,8 +1292,13 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync,
 {
        struct cfq_queue *cfqq, *new_cfqq = NULL;
        struct cfq_io_context *cic;
+       struct request_queue *q = cfqd->queue;
+       struct io_queue *ioq = NULL, *new_ioq = NULL;
+       struct io_group *iog = NULL;
 
 retry:
+       iog = elv_io_get_io_group(q, 0);
+
        cic = cfq_cic_lookup(cfqd, ioc);
        /* cic always exists here */
        cfqq = cic_to_cfqq(cic, is_sync);
@@ -1683,8 +1308,29 @@ retry:
         * originally, since it should just be a temporary situation.
         */
        if (!cfqq || cfqq == &cfqd->oom_cfqq) {
+               /* Allocate ioq object first and then cfqq */
+               if (new_ioq) {
+                       goto alloc_cfqq;
+               } else if (gfp_mask & __GFP_WAIT) {
+                       spin_unlock_irq(cfqd->queue->queue_lock);
+                       new_ioq = elv_alloc_ioq(q, gfp_mask | __GFP_ZERO);
+                       spin_lock_irq(cfqd->queue->queue_lock);
+                       if (new_ioq)
+                               goto retry;
+               } else
+                       ioq = elv_alloc_ioq(q, gfp_mask | __GFP_ZERO);
+
+alloc_cfqq:
+               if (!ioq && !new_ioq) {
+                       /* ioq allocation failed. Deafult to oom_cfqq */
+                       cfqq = &cfqd->oom_cfqq;
+                       goto out;
+               }
+
                cfqq = NULL;
                if (new_cfqq) {
+                       ioq = new_ioq;
+                       new_ioq = NULL;
                        cfqq = new_cfqq;
                        new_cfqq = NULL;
                } else if (gfp_mask & __GFP_WAIT) {
@@ -1702,60 +1348,59 @@ retry:
                }
 
                if (cfqq) {
+                       elv_init_ioq(q->elevator, ioq, current->pid, is_sync);
+                       elv_init_ioq_sched_queue(q->elevator, ioq, cfqq);
+
+                       cfqq->ioq = ioq;
                        cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
                        cfq_init_prio_data(cfqq, ioc);
+
+                       /* call it after cfq has initialized queue prio */
+                       elv_init_ioq_io_group(ioq, iog);
                        cfq_log_cfqq(cfqd, cfqq, "alloced");
-               } else
+               } else {
                        cfqq = &cfqd->oom_cfqq;
+                       /* If ioq allocation was successful, free it up */
+                       if (ioq)
+                               elv_free_ioq(ioq);
+               }
        }
 
+       if (new_ioq)
+               elv_free_ioq(new_ioq);
+
        if (new_cfqq)
                kmem_cache_free(cfq_pool, new_cfqq);
 
+out:
        return cfqq;
 }
 
-static struct cfq_queue **
-cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
-{
-       switch (ioprio_class) {
-       case IOPRIO_CLASS_RT:
-               return &cfqd->async_cfqq[0][ioprio];
-       case IOPRIO_CLASS_BE:
-               return &cfqd->async_cfqq[1][ioprio];
-       case IOPRIO_CLASS_IDLE:
-               return &cfqd->async_idle_cfqq;
-       default:
-               BUG();
-       }
-}
-
 static struct cfq_queue *
 cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc,
              gfp_t gfp_mask)
 {
        const int ioprio = task_ioprio(ioc);
        const int ioprio_class = task_ioprio_class(ioc);
-       struct cfq_queue **async_cfqq = NULL;
+       struct cfq_queue *async_cfqq = NULL;
        struct cfq_queue *cfqq = NULL;
+       struct io_group *iog = elv_io_get_io_group(cfqd->queue, 0);
 
        if (!is_sync) {
-               async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
-               cfqq = *async_cfqq;
+               async_cfqq = elv_io_group_async_queue_prio(iog, ioprio_class,
+                                                               ioprio);
+               cfqq = async_cfqq;
        }
 
        if (!cfqq)
                cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
 
-       /*
-        * pin the queue now that it's allocated, scheduler exit will prune it
-        */
-       if (!is_sync && !(*async_cfqq)) {
-               atomic_inc(&cfqq->ref);
-               *async_cfqq = cfqq;
-       }
+       if (!is_sync && !async_cfqq)
+               elv_io_group_set_async_queue(iog, ioprio_class, ioprio,
+                                                       cfqq->ioq);
 
-       atomic_inc(&cfqq->ref);
+       /* ioc reference */
+       elv_get_ioq(cfqq->ioq);
        return cfqq;
 }
 
@@ -1960,7 +1605,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct 
cfq_queue *cfqq,
        if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
                return;
 
-       enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
+       enable_idle = old_idle = elv_ioq_idle_window(cfqq->ioq);
 
        if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
            (cfqd->hw_tag && CIC_SEEKY(cic)))
@@ -1975,9 +1620,9 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct 
cfq_queue *cfqq,
        if (old_idle != enable_idle) {
                cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
                if (enable_idle)
-                       cfq_mark_cfqq_idle_window(cfqq);
+                       elv_mark_ioq_idle_window(cfqq->ioq);
                else
-                       cfq_clear_cfqq_idle_window(cfqq);
+                       elv_clear_ioq_idle_window(cfqq->ioq);
        }
 }
 
@@ -1986,16 +1631,15 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct 
cfq_queue *cfqq,
  * no or if we aren't sure, a 1 will cause a preempt.
  */
 static int
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-                  struct request *rq)
+cfq_should_preempt(struct request_queue *q, void *new_cfqq, struct request *rq)
 {
-       struct cfq_queue *cfqq;
+       struct cfq_data *cfqd = q->elevator->elevator_data;
+       struct cfq_queue *cfqq = elv_active_sched_queue(q->elevator);
 
-       cfqq = cfqd->active_queue;
        if (!cfqq)
                return 0;
 
-       if (cfq_slice_used(cfqq))
+       if (elv_ioq_slice_used(cfqq->ioq))
                return 1;
 
        if (cfq_class_idle(new_cfqq))
@@ -2018,13 +1662,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct 
cfq_queue *new_cfqq,
        if (rq_is_meta(rq) && !cfqq->meta_pending)
                return 1;
 
-       /*
-        * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
-        */
-       if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
-               return 1;
-
-       if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+       if (!cfqd->active_cic || !elv_ioq_wait_request(cfqq->ioq))
                return 0;
 
        /*
@@ -2038,27 +1676,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct 
cfq_queue *new_cfqq,
 }
 
 /*
- * 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)
-{
-       cfq_log_cfqq(cfqd, cfqq, "preempt");
-       cfq_slice_expired(cfqd, 1);
-
-       /*
-        * 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
  */
@@ -2077,36 +1694,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue 
*cfqq,
        cfq_update_idle_window(cfqd, cfqq, cic);
 
        cic->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_CACHE_SIZE ||
-                           cfqd->busy_queues > 1) {
-                               del_timer(&cfqd->idle_slice_timer);
-                       __blk_run_queue(cfqd->queue);
-                       }
-                       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)
@@ -2130,11 +1717,13 @@ static void cfq_insert_request(struct request_queue *q, 
struct request *rq)
  */
 static void cfq_update_hw_tag(struct cfq_data *cfqd)
 {
-       if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
-               cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+       struct elevator_queue *eq = cfqd->queue->elevator;
+
+       if (elv_rq_in_driver(eq) > cfqd->rq_in_driver_peak)
+               cfqd->rq_in_driver_peak = elv_rq_in_driver(eq);
 
        if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
-           cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+           elv_rq_in_driver(eq) <= CFQ_HW_QUEUE_MIN)
                return;
 
        if (cfqd->hw_tag_samples++ < 50)
@@ -2161,44 +1750,10 @@ static void cfq_completed_request(struct request_queue 
*q, struct request *rq)
 
        cfq_update_hw_tag(cfqd);
 
-       WARN_ON(!cfqd->rq_in_driver);
-       WARN_ON(!cfqq->dispatched);
-       cfqd->rq_in_driver--;
-       cfqq->dispatched--;
-
        if (cfq_cfqq_sync(cfqq))
                cfqd->sync_flight--;
-
        if (sync)
                RQ_CIC(rq)->last_end_request = now;
-
-       /*
-        * 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);
-               }
-               /*
-                * If there are no requests waiting in this queue, and
-                * there are other queues ready to issue requests, AND
-                * those other queues are issuing requests within our
-                * mean seek distance, give them a chance to run instead
-                * of idling.
-                */
-               if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
-                       cfq_slice_expired(cfqd, 1);
-               else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
-                        sync && !rq_noidle(rq))
-                       cfq_arm_slice_timer(cfqd);
-       }
-
-       if (!cfqd->rq_in_driver)
-               cfq_schedule_dispatch(cfqd);
 }
 
 /*
@@ -2207,29 +1762,32 @@ static void cfq_completed_request(struct request_queue 
*q, struct request *rq)
  */
 static void cfq_prio_boost(struct cfq_queue *cfqq)
 {
+       struct io_queue *ioq = cfqq->ioq;
+
        if (has_fs_excl()) {
                /*
                 * boost idle prio on transactions that would lock out other
                 * users of the filesystem
                 */
                if (cfq_class_idle(cfqq))
-                       cfqq->ioprio_class = IOPRIO_CLASS_BE;
-               if (cfqq->ioprio > IOPRIO_NORM)
-                       cfqq->ioprio = IOPRIO_NORM;
+                       elv_ioq_set_ioprio_class(ioq, IOPRIO_CLASS_BE);
+               if (elv_ioq_ioprio(ioq) > IOPRIO_NORM)
+                       elv_ioq_set_ioprio(ioq, IOPRIO_NORM);
+
        } else {
                /*
                 * check if we need to unboost the queue
                 */
-               if (cfqq->ioprio_class != cfqq->org_ioprio_class)
-                       cfqq->ioprio_class = cfqq->org_ioprio_class;
-               if (cfqq->ioprio != cfqq->org_ioprio)
-                       cfqq->ioprio = cfqq->org_ioprio;
+               if (elv_ioq_ioprio_class(ioq) != cfqq->org_ioprio_class)
+                       elv_ioq_set_ioprio_class(ioq, cfqq->org_ioprio_class);
+               if (elv_ioq_ioprio(ioq) != cfqq->org_ioprio)
+                       elv_ioq_set_ioprio(ioq, cfqq->org_ioprio);
        }
 }
 
 static inline int __cfq_may_queue(struct cfq_queue *cfqq)
 {
-       if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
+       if ((elv_ioq_wait_request(cfqq->ioq) || cfq_cfqq_must_alloc(cfqq)) &&
            !cfq_cfqq_must_alloc_slice(cfqq)) {
                cfq_mark_cfqq_must_alloc_slice(cfqq);
                return ELV_MQUEUE_MUST;
@@ -2282,7 +1840,7 @@ static void cfq_put_request(struct request *rq)
                put_io_context(RQ_CIC(rq)->ioc);
 
                rq->elevator_private = NULL;
-               rq->elevator_private2 = NULL;
+               rq->ioq = NULL;
 
                cfq_put_queue(cfqq);
        }
@@ -2318,119 +1876,31 @@ cfq_set_request(struct request_queue *q, struct 
request *rq, gfp_t gfp_mask)
 
        cfqq->allocated[rw]++;
        cfq_clear_cfqq_must_alloc(cfqq);
-       atomic_inc(&cfqq->ref);
+       elv_get_ioq(cfqq->ioq);
 
        spin_unlock_irqrestore(q->queue_lock, flags);
 
        rq->elevator_private = cic;
-       rq->elevator_private2 = cfqq;
+       rq->ioq = cfqq->ioq;
        return 0;
 
 queue_fail:
        if (cic)
                put_io_context(cic->ioc);
 
-       cfq_schedule_dispatch(cfqd);
+       elv_schedule_dispatch(cfqd->queue);
        spin_unlock_irqrestore(q->queue_lock, flags);
        cfq_log(cfqd, "set_request fail");
        return 1;
 }
 
-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 void cfq_idle_slice_timer(unsigned long data)
-{
-       struct cfq_data *cfqd = (struct cfq_data *) data;
-       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;
-       }
-expire:
-       cfq_slice_expired(cfqd, timed_out);
-out_kick:
-       cfq_schedule_dispatch(cfqd);
-out_cont:
-       spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
-{
-       del_timer_sync(&cfqd->idle_slice_timer);
-       cancel_work_sync(&cfqd->unplug_work);
-}
-
-static void cfq_put_async_queues(struct cfq_data *cfqd)
-{
-       int i;
-
-       for (i = 0; i < IOPRIO_BE_NR; i++) {
-               if (cfqd->async_cfqq[0][i])
-                       cfq_put_queue(cfqd->async_cfqq[0][i]);
-               if (cfqd->async_cfqq[1][i])
-                       cfq_put_queue(cfqd->async_cfqq[1][i]);
-       }
-
-       if (cfqd->async_idle_cfqq)
-               cfq_put_queue(cfqd->async_idle_cfqq);
-}
-
 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);
-
        while (!list_empty(&cfqd->cic_list)) {
                struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
                                                        struct cfq_io_context,
@@ -2439,12 +1909,7 @@ static void cfq_exit_queue(struct elevator_queue *e)
                __cfq_exit_single_io_context(cfqd, cic);
        }
 
-       cfq_put_async_queues(cfqd);
-
        spin_unlock_irq(q->queue_lock);
-
-       cfq_shutdown_timer_wq(cfqd);
-
        kfree(cfqd);
 }
 
@@ -2457,8 +1922,6 @@ static void *cfq_init_queue(struct request_queue *q, 
struct elevator_queue *eq)
        if (!cfqd)
                return NULL;
 
-       cfqd->service_tree = CFQ_RB_ROOT;
-
        /*
         * Not strictly needed (since RB_ROOT just clears the node and we
         * zeroed cfqd on alloc), but better be safe in case someone decides
@@ -2473,25 +1936,20 @@ static void *cfq_init_queue(struct request_queue *q, 
struct elevator_queue *eq)
         * will not attempt to free it.
         */
        cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-       atomic_inc(&cfqd->oom_cfqq.ref);
+
+       /* Link up oom_ioq and oom_cfqq */
+       cfqd->oom_cfqq.ioq = elv_get_oom_ioq(eq);
+       elv_init_ioq_sched_queue(eq, elv_get_oom_ioq(eq), &cfqd->oom_cfqq);
 
        INIT_LIST_HEAD(&cfqd->cic_list);
 
        cfqd->queue = q;
 
-       init_timer(&cfqd->idle_slice_timer);
-       cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-       cfqd->idle_slice_timer.data = (unsigned long) cfqd;
-
-       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_slice_async_rq = cfq_slice_async_rq;
        cfqd->cfq_slice_idle = cfq_slice_idle;
        cfqd->hw_tag = 1;
@@ -2560,8 +2018,6 @@ 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_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);
 #undef SHOW_FUNCTION
 
@@ -2590,8 +2046,6 @@ 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_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);
 #undef STORE_FUNCTION
@@ -2605,10 +2059,10 @@ static struct elv_fs_entry cfq_attrs[] = {
        CFQ_ATTR(fifo_expire_async),
        CFQ_ATTR(back_seek_max),
        CFQ_ATTR(back_seek_penalty),
-       CFQ_ATTR(slice_sync),
-       CFQ_ATTR(slice_async),
        CFQ_ATTR(slice_async_rq),
        CFQ_ATTR(slice_idle),
+       ELV_ATTR(slice_sync),
+       ELV_ATTR(slice_async),
        __ATTR_NULL
 };
 
@@ -2621,8 +2075,6 @@ static struct elevator_type iosched_cfq = {
                .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_queue_empty_fn =      cfq_queue_empty,
                .elevator_completed_req_fn =    cfq_completed_request,
                .elevator_former_req_fn =       elv_rb_former_request,
                .elevator_latter_req_fn =       elv_rb_latter_request,
@@ -2632,7 +2084,14 @@ static struct elevator_type iosched_cfq = {
                .elevator_init_fn =             cfq_init_queue,
                .elevator_exit_fn =             cfq_exit_queue,
                .trim =                         cfq_free_io_context,
+               .elevator_free_sched_queue_fn = cfq_free_cfq_queue,
+               .elevator_active_ioq_set_fn =   cfq_active_ioq_set,
+               .elevator_active_ioq_reset_fn = cfq_active_ioq_reset,
+               .elevator_arm_slice_timer_fn =  cfq_arm_slice_timer,
+               .elevator_should_preempt_fn =   cfq_should_preempt,
+               .elevator_close_cooperator_fn = cfq_close_cooperator,
        },
+       .elevator_features =    ELV_IOSCHED_NEED_FQ,
        .elevator_attrs =       cfq_attrs,
        .elevator_name =        "cfq",
        .elevator_owner =       THIS_MODULE,
@@ -2640,14 +2099,6 @@ static struct elevator_type iosched_cfq = {
 
 static int __init cfq_init(void)
 {
-       /*
-        * could be 0 on HZ < 1000 setups
-        */
-       if (!cfq_slice_async)
-               cfq_slice_async = 1;
-       if (!cfq_slice_idle)
-               cfq_slice_idle = 1;
-
        if (cfq_slab_setup())
                return -ENOMEM;
 
-- 
1.6.0.6

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