1 files changed, 116 insertions, 510 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3548705b04e..ee55019066a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -14,6 +14,7 @@
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/blktrace_api.h>
+#include "blk.h"
 #include "cfq.h"
 
 /*
@@ -53,20 +54,11 @@ static const int cfq_hist_divisor = 4;
 #define CFQQ_SECT_THR_NONROT	(sector_t)(2 * 32)
 #define CFQQ_SEEKY(cfqq)	(hweight32(cfqq->seek_history) > 32/8)
 
-#define RQ_CIC(rq)		\
-	((struct cfq_io_context *) (rq)->elevator_private[0])
-#define RQ_CFQQ(rq)		(struct cfq_queue *) ((rq)->elevator_private[1])
-#define RQ_CFQG(rq)		(struct cfq_group *) ((rq)->elevator_private[2])
+#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;
-static struct kmem_cache *cfq_ioc_pool;
-
-static DEFINE_PER_CPU(unsigned long, cfq_ioc_count);
-static struct completion *ioc_gone;
-static DEFINE_SPINLOCK(ioc_gone_lock);
-
-static DEFINE_SPINLOCK(cic_index_lock);
-static DEFINE_IDA(cic_index_ida);
 
 #define CFQ_PRIO_LISTS		IOPRIO_BE_NR
 #define cfq_class_idle(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
@@ -75,6 +67,14 @@ static DEFINE_IDA(cic_index_ida);
 #define sample_valid(samples)	((samples) > 80)
 #define rb_entry_cfqg(node)	rb_entry((node), struct cfq_group, rb_node)
 
+struct cfq_ttime {
+	unsigned long last_end_request;
+
+	unsigned long ttime_total;
+	unsigned long ttime_samples;
+	unsigned long ttime_mean;
+};
+
 /*
  * 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
@@ -216,6 +216,12 @@ struct cfq_group {
 	struct cfq_ttime ttime;
 };
 
+struct cfq_io_cq {
+	struct io_cq		icq;		/* must be the first member */
+	struct cfq_queue	*cfqq[2];
+	struct cfq_ttime	ttime;
+};
+
 /*
  * Per block device queue structure
  */
@@ -267,7 +273,7 @@ struct cfq_data {
 	struct work_struct unplug_work;
 
 	struct cfq_queue *active_queue;
-	struct cfq_io_context *active_cic;
+	struct cfq_io_cq *active_cic;
 
 	/*
 	 * async queue for each priority case
@@ -290,9 +296,6 @@ struct cfq_data {
 	unsigned int cfq_group_idle;
 	unsigned int cfq_latency;
 
-	unsigned int cic_index;
-	struct list_head cic_list;
-
 	/*
 	 * Fallback dummy cfqq for extreme OOM conditions
 	 */
@@ -464,37 +467,35 @@ static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
 static void cfq_dispatch_insert(struct request_queue *, struct request *);
 static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
 				       struct io_context *, gfp_t);
-static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
-						struct io_context *);
 
-static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
-					    bool is_sync)
+static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
 {
-	return cic->cfqq[is_sync];
+	/* cic->icq is the first member, %NULL will convert to %NULL */
+	return container_of(icq, struct cfq_io_cq, icq);
 }
 
-static inline void cic_set_cfqq(struct cfq_io_context *cic,
-				struct cfq_queue *cfqq, bool is_sync)
+static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd,
+					       struct io_context *ioc)
 {
-	cic->cfqq[is_sync] = cfqq;
+	if (ioc)
+		return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue));
+	return NULL;
 }
 
-#define CIC_DEAD_KEY	1ul
-#define CIC_DEAD_INDEX_SHIFT	1
-
-static inline void *cfqd_dead_key(struct cfq_data *cfqd)
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync)
 {
-	return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY);
+	return cic->cfqq[is_sync];
 }
 
-static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic)
+static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
+				bool is_sync)
 {
-	struct cfq_data *cfqd = cic->key;
-
-	if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY))
-		return NULL;
+	cic->cfqq[is_sync] = cfqq;
+}
 
-	return cfqd;
+static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic)
+{
+	return cic->icq.q->elevator->elevator_data;
 }
 
 /*
@@ -1561,7 +1562,7 @@ static struct request *
 cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
 {
 	struct task_struct *tsk = current;
-	struct cfq_io_context *cic;
+	struct cfq_io_cq *cic;
 	struct cfq_queue *cfqq;
 
 	cic = cfq_cic_lookup(cfqd, tsk->io_context);
@@ -1687,7 +1688,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 			   struct bio *bio)
 {
 	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_io_context *cic;
+	struct cfq_io_cq *cic;
 	struct cfq_queue *cfqq;
 
 	/*
@@ -1697,12 +1698,19 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 		return false;
 
 	/*
-	 * Lookup the cfqq that this bio will be queued with. Allow
-	 * merge only if rq is queued there.
+	 * Lookup the cfqq that this bio will be queued with and allow
+	 * merge only if rq is queued there.  This function can be called
+	 * from plug merge without queue_lock.  In such cases, ioc of @rq
+	 * and %current are guaranteed to be equal.  Avoid lookup which
+	 * requires queue_lock by using @rq's cic.
 	 */
-	cic = cfq_cic_lookup(cfqd, current->io_context);
-	if (!cic)
-		return false;
+	if (current->io_context == RQ_CIC(rq)->icq.ioc) {
+		cic = RQ_CIC(rq);
+	} else {
+		cic = cfq_cic_lookup(cfqd, current->io_context);
+		if (!cic)
+			return false;
+	}
 
 	cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
 	return cfqq == RQ_CFQQ(rq);
@@ -1786,7 +1794,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		cfqd->active_queue = NULL;
 
 	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->ioc);
+		put_io_context(cfqd->active_cic->icq.ioc, cfqd->queue);
 		cfqd->active_cic = NULL;
 	}
 }
@@ -2006,7 +2014,7 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 {
 	struct cfq_queue *cfqq = cfqd->active_queue;
-	struct cfq_io_context *cic;
+	struct cfq_io_cq *cic;
 	unsigned long sl, group_idle = 0;
 
 	/*
@@ -2041,7 +2049,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	 * task has exited, don't wait
 	 */
 	cic = cfqd->active_cic;
-	if (!cic || !atomic_read(&cic->ioc->nr_tasks))
+	if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
 		return;
 
 	/*
@@ -2592,9 +2600,9 @@ static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	cfq_dispatch_insert(cfqd->queue, rq);
 
 	if (!cfqd->active_cic) {
-		struct cfq_io_context *cic = RQ_CIC(rq);
+		struct cfq_io_cq *cic = RQ_CIC(rq);
 
-		atomic_long_inc(&cic->ioc->refcount);
+		atomic_long_inc(&cic->icq.ioc->refcount);
 		cfqd->active_cic = cic;
 	}
 
@@ -2677,84 +2685,6 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
 	cfq_put_cfqg(cfqg);
 }
 
-/*
- * Call func for each cic attached to this ioc.
- */
-static void
-call_for_each_cic(struct io_context *ioc,
-		  void (*func)(struct io_context *, struct cfq_io_context *))
-{
-	struct cfq_io_context *cic;
-	struct hlist_node *n;
-
-	rcu_read_lock();
-
-	hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list)
-		func(ioc, cic);
-
-	rcu_read_unlock();
-}
-
-static void cfq_cic_free_rcu(struct rcu_head *head)
-{
-	struct cfq_io_context *cic;
-
-	cic = container_of(head, struct cfq_io_context, rcu_head);
-
-	kmem_cache_free(cfq_ioc_pool, cic);
-	elv_ioc_count_dec(cfq_ioc_count);
-
-	if (ioc_gone) {
-		/*
-		 * CFQ scheduler is exiting, grab exit lock and check
-		 * the pending io context count. If it hits zero,
-		 * complete ioc_gone and set it back to NULL
-		 */
-		spin_lock(&ioc_gone_lock);
-		if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) {
-			complete(ioc_gone);
-			ioc_gone = NULL;
-		}
-		spin_unlock(&ioc_gone_lock);
-	}
-}
-
-static void cfq_cic_free(struct cfq_io_context *cic)
-{
-	call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
-}
-
-static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
-{
-	unsigned long flags;
-	unsigned long dead_key = (unsigned long) cic->key;
-
-	BUG_ON(!(dead_key & CIC_DEAD_KEY));
-
-	spin_lock_irqsave(&ioc->lock, flags);
-	radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT);
-	hlist_del_rcu(&cic->cic_list);
-	spin_unlock_irqrestore(&ioc->lock, flags);
-
-	cfq_cic_free(cic);
-}
-
-/*
- * Must be called with rcu_read_lock() held or preemption otherwise disabled.
- * Only two callers of this - ->dtor() which is called with the rcu_read_lock(),
- * and ->trim() which is called with the task lock held
- */
-static void cfq_free_io_context(struct io_context *ioc)
-{
-	/*
-	 * ioc->refcount is zero here, or we are called from elv_unregister(),
-	 * so no more cic's are allowed to be linked into this ioc.  So it
-	 * should be ok to iterate over the known list, we will see all cic's
-	 * since no new ones are added.
-	 */
-	call_for_each_cic(ioc, cic_free_func);
-}
-
 static void cfq_put_cooperator(struct cfq_queue *cfqq)
 {
 	struct cfq_queue *__cfqq, *next;
@@ -2788,27 +2718,17 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	cfq_put_queue(cfqq);
 }
 
-static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
-					 struct cfq_io_context *cic)
+static void cfq_init_icq(struct io_cq *icq)
 {
-	struct io_context *ioc = cic->ioc;
+	struct cfq_io_cq *cic = icq_to_cic(icq);
 
-	list_del_init(&cic->queue_list);
-
-	/*
-	 * Make sure dead mark is seen for dead queues
-	 */
-	smp_wmb();
-	cic->key = cfqd_dead_key(cfqd);
+	cic->ttime.last_end_request = jiffies;
+}
 
-	rcu_read_lock();
-	if (rcu_dereference(ioc->ioc_data) == cic) {
-		rcu_read_unlock();
-		spin_lock(&ioc->lock);
-		rcu_assign_pointer(ioc->ioc_data, NULL);
-		spin_unlock(&ioc->lock);
-	} else
-		rcu_read_unlock();
+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->cfqq[BLK_RW_ASYNC]) {
 		cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
@@ -2821,57 +2741,6 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
 	}
 }
 
-static void cfq_exit_single_io_context(struct io_context *ioc,
-				       struct cfq_io_context *cic)
-{
-	struct cfq_data *cfqd = cic_to_cfqd(cic);
-
-	if (cfqd) {
-		struct request_queue *q = cfqd->queue;
-		unsigned long flags;
-
-		spin_lock_irqsave(q->queue_lock, flags);
-
-		/*
-		 * Ensure we get a fresh copy of the ->key to prevent
-		 * race between exiting task and queue
-		 */
-		smp_read_barrier_depends();
-		if (cic->key == cfqd)
-			__cfq_exit_single_io_context(cfqd, cic);
-
-		spin_unlock_irqrestore(q->queue_lock, flags);
-	}
-}
-
-/*
- * The process that ioc belongs to has exited, we need to clean up
- * and put the internal structures we have that belongs to that process.
- */
-static void cfq_exit_io_context(struct io_context *ioc)
-{
-	call_for_each_cic(ioc, cfq_exit_single_io_context);
-}
-
-static struct cfq_io_context *
-cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
-	struct cfq_io_context *cic;
-
-	cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
-							cfqd->queue->node);
-	if (cic) {
-		cic->ttime.last_end_request = jiffies;
-		INIT_LIST_HEAD(&cic->queue_list);
-		INIT_HLIST_NODE(&cic->cic_list);
-		cic->dtor = cfq_free_io_context;
-		cic->exit = cfq_exit_io_context;
-		elv_ioc_count_inc(cfq_ioc_count);
-	}
-
-	return cic;
-}
-
 static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 {
 	struct task_struct *tsk = current;
@@ -2914,21 +2783,18 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 	cfq_clear_cfqq_prio_changed(cfqq);
 }
 
-static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
+static void changed_ioprio(struct cfq_io_cq *cic)
 {
 	struct cfq_data *cfqd = cic_to_cfqd(cic);
 	struct cfq_queue *cfqq;
-	unsigned long flags;
 
 	if (unlikely(!cfqd))
 		return;
 
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
 	cfqq = cic->cfqq[BLK_RW_ASYNC];
 	if (cfqq) {
 		struct cfq_queue *new_cfqq;
-		new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc,
+		new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc,
 						GFP_ATOMIC);
 		if (new_cfqq) {
 			cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
@@ -2939,14 +2805,6 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
 	cfqq = cic->cfqq[BLK_RW_SYNC];
 	if (cfqq)
 		cfq_mark_cfqq_prio_changed(cfqq);
-
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-static void cfq_ioc_set_ioprio(struct io_context *ioc)
-{
-	call_for_each_cic(ioc, changed_ioprio);
-	ioc->ioprio_changed = 0;
 }
 
 static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
@@ -2970,11 +2828,10 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
+static void changed_cgroup(struct cfq_io_cq *cic)
 {
 	struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
 	struct cfq_data *cfqd = cic_to_cfqd(cic);
-	unsigned long flags;
 	struct request_queue *q;
 
 	if (unlikely(!cfqd))
@@ -2982,8 +2839,6 @@ static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
 
 	q = cfqd->queue;
 
-	spin_lock_irqsave(q->queue_lock, flags);
-
 	if (sync_cfqq) {
 		/*
 		 * Drop reference to sync queue. A new sync queue will be
@@ -2993,14 +2848,6 @@ static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
 		cic_set_cfqq(cic, NULL, 1);
 		cfq_put_queue(sync_cfqq);
 	}
-
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static void cfq_ioc_set_cgroup(struct io_context *ioc)
-{
-	call_for_each_cic(ioc, changed_cgroup);
-	ioc->cgroup_changed = 0;
 }
 #endif  /* CONFIG_CFQ_GROUP_IOSCHED */
 
@@ -3009,7 +2856,7 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
 		     struct io_context *ioc, gfp_t gfp_mask)
 {
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
-	struct cfq_io_context *cic;
+	struct cfq_io_cq *cic;
 	struct cfq_group *cfqg;
 
 retry:
@@ -3100,160 +2947,6 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
 	return cfqq;
 }
 
-/*
- * We drop cfq io contexts lazily, so we may find a dead one.
- */
-static void
-cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
-		  struct cfq_io_context *cic)
-{
-	unsigned long flags;
-
-	WARN_ON(!list_empty(&cic->queue_list));
-	BUG_ON(cic->key != cfqd_dead_key(cfqd));
-
-	spin_lock_irqsave(&ioc->lock, flags);
-
-	BUG_ON(rcu_dereference_check(ioc->ioc_data,
-		lockdep_is_held(&ioc->lock)) == cic);
-
-	radix_tree_delete(&ioc->radix_root, cfqd->cic_index);
-	hlist_del_rcu(&cic->cic_list);
-	spin_unlock_irqrestore(&ioc->lock, flags);
-
-	cfq_cic_free(cic);
-}
-
-static struct cfq_io_context *
-cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
-{
-	struct cfq_io_context *cic;
-	unsigned long flags;
-
-	if (unlikely(!ioc))
-		return NULL;
-
-	rcu_read_lock();
-
-	/*
-	 * we maintain a last-hit cache, to avoid browsing over the tree
-	 */
-	cic = rcu_dereference(ioc->ioc_data);
-	if (cic && cic->key == cfqd) {
-		rcu_read_unlock();
-		return cic;
-	}
-
-	do {
-		cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index);
-		rcu_read_unlock();
-		if (!cic)
-			break;
-		if (unlikely(cic->key != cfqd)) {
-			cfq_drop_dead_cic(cfqd, ioc, cic);
-			rcu_read_lock();
-			continue;
-		}
-
-		spin_lock_irqsave(&ioc->lock, flags);
-		rcu_assign_pointer(ioc->ioc_data, cic);
-		spin_unlock_irqrestore(&ioc->lock, flags);
-		break;
-	} while (1);
-
-	return cic;
-}
-
-/*
- * Add cic into ioc, using cfqd as the search key. This enables us to lookup
- * the process specific cfq io context when entered from the block layer.
- * Also adds the cic to a per-cfqd list, used when this queue is removed.
- */
-static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
-			struct cfq_io_context *cic, gfp_t gfp_mask)
-{
-	unsigned long flags;
-	int ret;
-
-	ret = radix_tree_preload(gfp_mask);
-	if (!ret) {
-		cic->ioc = ioc;
-		cic->key = cfqd;
-
-		spin_lock_irqsave(&ioc->lock, flags);
-		ret = radix_tree_insert(&ioc->radix_root,
-						cfqd->cic_index, cic);
-		if (!ret)
-			hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list);
-		spin_unlock_irqrestore(&ioc->lock, flags);
-
-		radix_tree_preload_end();
-
-		if (!ret) {
-			spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-			list_add(&cic->queue_list, &cfqd->cic_list);
-			spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-		}
-	}
-
-	if (ret && ret != -EEXIST)
-		printk(KERN_ERR "cfq: cic link failed!\n");
-
-	return ret;
-}
-
-/*
- * Setup general io context and cfq io context. There can be several cfq
- * io contexts per general io context, if this process is doing io to more
- * than one device managed by cfq.
- */
-static struct cfq_io_context *
-cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
-	struct io_context *ioc = NULL;
-	struct cfq_io_context *cic;
-	int ret;
-
-	might_sleep_if(gfp_mask & __GFP_WAIT);
-
-	ioc = get_io_context(gfp_mask, cfqd->queue->node);
-	if (!ioc)
-		return NULL;
-
-retry:
-	cic = cfq_cic_lookup(cfqd, ioc);
-	if (cic)
-		goto out;
-
-	cic = cfq_alloc_io_context(cfqd, gfp_mask);
-	if (cic == NULL)
-		goto err;
-
-	ret = cfq_cic_link(cfqd, ioc, cic, gfp_mask);
-	if (ret == -EEXIST) {
-		/* someone has linked cic to ioc already */
-		cfq_cic_free(cic);
-		goto retry;
-	} else if (ret)
-		goto err_free;
-
-out:
-	smp_read_barrier_depends();
-	if (unlikely(ioc->ioprio_changed))
-		cfq_ioc_set_ioprio(ioc);
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-	if (unlikely(ioc->cgroup_changed))
-		cfq_ioc_set_cgroup(ioc);
-#endif
-	return cic;
-err_free:
-	cfq_cic_free(cic);
-err:
-	put_io_context(ioc);
-	return NULL;
-}
-
 static void
 __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)
 {
@@ -3267,7 +2960,7 @@ __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)
 
 static void
 cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-	struct cfq_io_context *cic)
+			struct cfq_io_cq *cic)
 {
 	if (cfq_cfqq_sync(cfqq)) {
 		__cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle);
@@ -3305,7 +2998,7 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
  */
 static void
 cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		       struct cfq_io_context *cic)
+		       struct cfq_io_cq *cic)
 {
 	int old_idle, enable_idle;
 
@@ -3322,8 +3015,9 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 
 	if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
 		enable_idle = 0;
-	else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
-	    (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
+	else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
+		 !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)
@@ -3423,18 +3117,17 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
  */
 static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	struct cfq_queue *old_cfqq = 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 (cfqq_type(old_cfqq) != cfqq_type(cfqq))
+	if (cfqq_type(cfqd->active_queue) != cfqq_type(cfqq))
 		cfqq->cfqg->saved_workload_slice = 0;
 
+	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.
@@ -3455,7 +3148,7 @@ static void
 cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		struct request *rq)
 {
-	struct cfq_io_context *cic = RQ_CIC(rq);
+	struct cfq_io_cq *cic = RQ_CIC(rq);
 
 	cfqd->rq_queued++;
 	if (rq->cmd_flags & REQ_PRIO)
@@ -3508,7 +3201,7 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
 
 	cfq_log_cfqq(cfqd, cfqq, "insert_request");
-	cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
+	cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc);
 
 	rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
 	list_add_tail(&rq->queuelist, &cfqq->fifo);
@@ -3558,7 +3251,7 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd)
 
 static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	struct cfq_io_context *cic = cfqd->active_cic;
+	struct cfq_io_cq *cic = cfqd->active_cic;
 
 	/* If the queue already has requests, don't wait */
 	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
@@ -3695,7 +3388,7 @@ static int cfq_may_queue(struct request_queue *q, int rw)
 {
 	struct cfq_data *cfqd = q->elevator->elevator_data;
 	struct task_struct *tsk = current;
-	struct cfq_io_context *cic;
+	struct cfq_io_cq *cic;
 	struct cfq_queue *cfqq;
 
 	/*
@@ -3710,7 +3403,7 @@ static int cfq_may_queue(struct request_queue *q, int rw)
 
 	cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
 	if (cfqq) {
-		cfq_init_prio_data(cfqq, cic->ioc);
+		cfq_init_prio_data(cfqq, cic->icq.ioc);
 
 		return __cfq_may_queue(cfqq);
 	}
@@ -3731,21 +3424,17 @@ static void cfq_put_request(struct request *rq)
 		BUG_ON(!cfqq->allocated[rw]);
 		cfqq->allocated[rw]--;
 
-		put_io_context(RQ_CIC(rq)->ioc);
-
-		rq->elevator_private[0] = NULL;
-		rq->elevator_private[1] = NULL;
-
 		/* Put down rq reference on cfqg */
 		cfq_put_cfqg(RQ_CFQG(rq));
-		rq->elevator_private[2] = NULL;
+		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_context *cic,
+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);
@@ -3760,7 +3449,7 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
  * was the last process referring to said cfqq.
  */
 static struct cfq_queue *
-split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
+split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
 {
 	if (cfqq_process_refs(cfqq) == 1) {
 		cfqq->pid = current->pid;
@@ -3783,25 +3472,29 @@ static int
 cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
 {
 	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_io_context *cic;
+	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;
-	unsigned long flags;
 
 	might_sleep_if(gfp_mask & __GFP_WAIT);
 
-	cic = cfq_get_io_context(cfqd, gfp_mask);
-
-	spin_lock_irqsave(q->queue_lock, flags);
+	spin_lock_irq(q->queue_lock);
 
-	if (!cic)
-		goto queue_fail;
+	/* handle changed notifications */
+	if (unlikely(cic->icq.changed)) {
+		if (test_and_clear_bit(ICQ_IOPRIO_CHANGED, &cic->icq.changed))
+			changed_ioprio(cic);
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+		if (test_and_clear_bit(ICQ_CGROUP_CHANGED, &cic->icq.changed))
+			changed_cgroup(cic);
+#endif
+	}
 
 new_queue:
 	cfqq = cic_to_cfqq(cic, is_sync);
 	if (!cfqq || cfqq == &cfqd->oom_cfqq) {
-		cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
+		cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask);
 		cic_set_cfqq(cic, cfqq, is_sync);
 	} else {
 		/*
@@ -3827,17 +3520,10 @@ new_queue:
 	cfqq->allocated[rw]++;
 
 	cfqq->ref++;
-	rq->elevator_private[0] = cic;
-	rq->elevator_private[1] = cfqq;
-	rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
-	spin_unlock_irqrestore(q->queue_lock, flags);
+	rq->elv.priv[0] = cfqq;
+	rq->elv.priv[1] = cfq_ref_get_cfqg(cfqq->cfqg);
+	spin_unlock_irq(q->queue_lock);
 	return 0;
-
-queue_fail:
-	cfq_schedule_dispatch(cfqd);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-	cfq_log(cfqd, "set_request fail");
-	return 1;
 }
 
 static void cfq_kick_queue(struct work_struct *work)
@@ -3941,14 +3627,6 @@ static void cfq_exit_queue(struct elevator_queue *e)
 	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,
-							queue_list);
-
-		__cfq_exit_single_io_context(cfqd, cic);
-	}
-
 	cfq_put_async_queues(cfqd);
 	cfq_release_cfq_groups(cfqd);
 
@@ -3963,10 +3641,6 @@ static void cfq_exit_queue(struct elevator_queue *e)
 
 	cfq_shutdown_timer_wq(cfqd);
 
-	spin_lock(&cic_index_lock);
-	ida_remove(&cic_index_ida, cfqd->cic_index);
-	spin_unlock(&cic_index_lock);
-
 	/*
 	 * Wait for cfqg->blkg->key accessors to exit their grace periods.
 	 * Do this wait only if there are other unlinked groups out
@@ -3988,24 +3662,6 @@ static void cfq_exit_queue(struct elevator_queue *e)
 	kfree(cfqd);
 }
 
-static int cfq_alloc_cic_index(void)
-{
-	int index, error;
-
-	do {
-		if (!ida_pre_get(&cic_index_ida, GFP_KERNEL))
-			return -ENOMEM;
-
-		spin_lock(&cic_index_lock);
-		error = ida_get_new(&cic_index_ida, &index);
-		spin_unlock(&cic_index_lock);
-		if (error && error != -EAGAIN)
-			return error;
-	} while (error);
-
-	return index;
-}
-
 static void *cfq_init_queue(struct request_queue *q)
 {
 	struct cfq_data *cfqd;
@@ -4013,23 +3669,9 @@ static void *cfq_init_queue(struct request_queue *q)
 	struct cfq_group *cfqg;
 	struct cfq_rb_root *st;
 
-	i = cfq_alloc_cic_index();
-	if (i < 0)
-		return NULL;
-
 	cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
-	if (!cfqd) {
-		spin_lock(&cic_index_lock);
-		ida_remove(&cic_index_ida, i);
-		spin_unlock(&cic_index_lock);
+	if (!cfqd)
 		return NULL;
-	}
-
-	/*
-	 * Don't need take queue_lock in the routine, since we are
-	 * initializing the ioscheduler, and nobody is using cfqd
-	 */
-	cfqd->cic_index = i;
 
 	/* Init root service tree */
 	cfqd->grp_service_tree = CFQ_RB_ROOT;
@@ -4055,11 +3697,6 @@ static void *cfq_init_queue(struct request_queue *q)
 
 	if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
 		kfree(cfqg);
-
-		spin_lock(&cic_index_lock);
-		ida_remove(&cic_index_ida, cfqd->cic_index);
-		spin_unlock(&cic_index_lock);
-
 		kfree(cfqd);
 		return NULL;
 	}
@@ -4091,8 +3728,6 @@ static void *cfq_init_queue(struct request_queue *q)
 	cfqd->oom_cfqq.ref++;
 	cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
 
-	INIT_LIST_HEAD(&cfqd->cic_list);
-
 	cfqd->queue = q;
 
 	init_timer(&cfqd->idle_slice_timer);
@@ -4121,34 +3756,6 @@ static void *cfq_init_queue(struct request_queue *q)
 	return cfqd;
 }
 
-static void cfq_slab_kill(void)
-{
-	/*
-	 * Caller already ensured that pending RCU callbacks are completed,
-	 * so we should have no busy allocations at this point.
-	 */
-	if (cfq_pool)
-		kmem_cache_destroy(cfq_pool);
-	if (cfq_ioc_pool)
-		kmem_cache_destroy(cfq_ioc_pool);
-}
-
-static int __init cfq_slab_setup(void)
-{
-	cfq_pool = KMEM_CACHE(cfq_queue, 0);
-	if (!cfq_pool)
-		goto fail;
-
-	cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
-	if (!cfq_ioc_pool)
-		goto fail;
-
-	return 0;
-fail:
-	cfq_slab_kill();
-	return -ENOMEM;
-}
-
 /*
  * sysfs parts below -->
  */
@@ -4254,15 +3861,18 @@ static struct elevator_type iosched_cfq = {
 		.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,
-		.trim =				cfq_free_io_context,
 	},
+	.icq_size	=	sizeof(struct cfq_io_cq),
+	.icq_align	=	__alignof__(struct cfq_io_cq),
 	.elevator_attrs =	cfq_attrs,
-	.elevator_name =	"cfq",
+	.elevator_name	=	"cfq",
 	.elevator_owner =	THIS_MODULE,
 };
 
@@ -4280,6 +3890,8 @@ static struct blkio_policy_type blkio_policy_cfq;
 
 static int __init cfq_init(void)
 {
+	int ret;
+
 	/*
 	 * could be 0 on HZ < 1000 setups
 	 */
@@ -4294,10 +3906,16 @@ static int __init cfq_init(void)
 #else
 		cfq_group_idle = 0;
 #endif
-	if (cfq_slab_setup())
+	cfq_pool = KMEM_CACHE(cfq_queue, 0);
+	if (!cfq_pool)
 		return -ENOMEM;
 
-	elv_register(&iosched_cfq);
+	ret = elv_register(&iosched_cfq);
+	if (ret) {
+		kmem_cache_destroy(cfq_pool);
+		return ret;
+	}
+
 	blkio_policy_register(&blkio_policy_cfq);
 
 	return 0;
@@ -4305,21 +3923,9 @@ static int __init cfq_init(void)
 
 static void __exit cfq_exit(void)
 {
-	DECLARE_COMPLETION_ONSTACK(all_gone);
 	blkio_policy_unregister(&blkio_policy_cfq);
 	elv_unregister(&iosched_cfq);
-	ioc_gone = &all_gone;
-	/* ioc_gone's update must be visible before reading ioc_count */
-	smp_wmb();
-
-	/*
-	 * this also protects us from entering cfq_slab_kill() with
-	 * pending RCU callbacks
-	 */
-	if (elv_ioc_count_read(cfq_ioc_count))
-		wait_for_completion(&all_gone);
-	ida_destroy(&cic_index_ida);
-	cfq_slab_kill();
+	kmem_cache_destroy(cfq_pool);
 }
 
 module_init(cfq_init);