Merge with http://kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

1 files changed, 0 insertions, 2428 deletions

diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c
deleted file mode 100644
index ecacca9c877e..000000000000
--- a/drivers/block/cfq-iosched.c
+++ /dev/null
@@ -1,2428 +0,0 @@
-/*
- *  linux/drivers/block/cfq-iosched.c
- *
- *  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@suse.de>
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/hash.h>
-#include <linux/rbtree.h>
-#include <linux/mempool.h>
-#include <linux/ioprio.h>
-#include <linux/writeback.h>
-
-/*
- * tunables
- */
-static int cfq_quantum = 4;		/* max queue in one round of service */
-static int cfq_queued = 8;		/* minimum rq allocate limit per-queue*/
-static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
-static int cfq_back_max = 16 * 1024;	/* maximum backwards seek, in KiB */
-static int cfq_back_penalty = 2;	/* penalty of a backwards seek */
-
-static int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
-static int cfq_slice_async_rq = 2;
-static int cfq_slice_idle = HZ / 100;
-
-#define CFQ_IDLE_GRACE		(HZ / 10)
-#define CFQ_SLICE_SCALE		(5)
-
-#define CFQ_KEY_ASYNC		(0)
-#define CFQ_KEY_ANY		(0xffff)
-
-/*
- * disable queueing at the driver/hardware level
- */
-static int cfq_max_depth = 2;
-
-/*
- * for the hash of cfqq inside the cfqd
- */
-#define CFQ_QHASH_SHIFT		6
-#define CFQ_QHASH_ENTRIES	(1 << CFQ_QHASH_SHIFT)
-#define list_entry_qhash(entry)	hlist_entry((entry), struct cfq_queue, cfq_hash)
-
-/*
- * for the hash of crq inside the cfqq
- */
-#define CFQ_MHASH_SHIFT		6
-#define CFQ_MHASH_BLOCK(sec)	((sec) >> 3)
-#define CFQ_MHASH_ENTRIES	(1 << CFQ_MHASH_SHIFT)
-#define CFQ_MHASH_FN(sec)	hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
-#define rq_hash_key(rq)		((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)	hlist_entry((ptr), struct cfq_rq, hash)
-
-#define list_entry_cfqq(ptr)	list_entry((ptr), struct cfq_queue, cfq_list)
-#define list_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)
-
-#define RQ_DATA(rq)		(rq)->elevator_private
-
-/*
- * rb-tree defines
- */
-#define RB_NONE			(2)
-#define RB_EMPTY(node)		((node)->rb_node == NULL)
-#define RB_CLEAR_COLOR(node)	(node)->rb_color = RB_NONE
-#define RB_CLEAR(node)		do {	\
-	(node)->rb_parent = NULL;	\
-	RB_CLEAR_COLOR((node));		\
-	(node)->rb_right = NULL;	\
-	(node)->rb_left = NULL;		\
-} while (0)
-#define RB_CLEAR_ROOT(root)	((root)->rb_node = NULL)
-#define rb_entry_crq(node)	rb_entry((node), struct cfq_rq, rb_node)
-#define rq_rb_key(rq)		(rq)->sector
-
-static kmem_cache_t *crq_pool;
-static kmem_cache_t *cfq_pool;
-static kmem_cache_t *cfq_ioc_pool;
-
-#define CFQ_PRIO_LISTS		IOPRIO_BE_NR
-#define cfq_class_idle(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_be(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
-#define cfq_class_rt(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
-
-#define ASYNC			(0)
-#define SYNC			(1)
-
-#define cfq_cfqq_dispatched(cfqq)	\
-	((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
-
-#define cfq_cfqq_class_sync(cfqq)	((cfqq)->key != CFQ_KEY_ASYNC)
-
-#define cfq_cfqq_sync(cfqq)		\
-	(cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
-
-/*
- * Per block device queue structure
- */
-struct cfq_data {
-	atomic_t ref;
-	request_queue_t *queue;
-
-	/*
-	 * rr list of queues with requests and the count of them
-	 */
-	struct list_head rr_list[CFQ_PRIO_LISTS];
-	struct list_head busy_rr;
-	struct list_head cur_rr;
-	struct list_head idle_rr;
-	unsigned int busy_queues;
-
-	/*
-	 * non-ordered list of empty cfqq's
-	 */
-	struct list_head empty_list;
-
-	/*
-	 * cfqq lookup hash
-	 */
-	struct hlist_head *cfq_hash;
-
-	/*
-	 * global crq hash for all queues
-	 */
-	struct hlist_head *crq_hash;
-
-	unsigned int max_queued;
-
-	mempool_t *crq_pool;
-
-	int rq_in_driver;
-
-	/*
-	 * schedule slice state info
-	 */
-	/*
-	 * 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;
-	int cur_prio, cur_end_prio;
-	unsigned int dispatch_slice;
-
-	struct timer_list idle_class_timer;
-
-	sector_t last_sector;
-	unsigned long last_end_request;
-
-	unsigned int rq_starved;
-
-	/*
-	 * tunables, see top of file
-	 */
-	unsigned int cfq_quantum;
-	unsigned int cfq_queued;
-	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;
-	unsigned int cfq_max_depth;
-};
-
-/*
- * Per process-grouping structure
- */
-struct cfq_queue {
-	/* reference count */
-	atomic_t ref;
-	/* parent cfq_data */
-	struct cfq_data *cfqd;
-	/* cfqq lookup hash */
-	struct hlist_node cfq_hash;
-	/* hash key */
-	unsigned int key;
-	/* on either rr or empty list of cfqd */
-	struct list_head cfq_list;
-	/* sorted list of pending requests */
-	struct rb_root sort_list;
-	/* if fifo isn't expired, next request to serve */
-	struct cfq_rq *next_crq;
-	/* 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;
-
-	unsigned long slice_start;
-	unsigned long slice_end;
-	unsigned long slice_left;
-	unsigned long service_last;
-
-	/* number of requests that are on the dispatch list */
-	int on_dispatch[2];
-
-	/* io prio of this group */
-	unsigned short ioprio, org_ioprio;
-	unsigned short ioprio_class, org_ioprio_class;
-
-	/* various state flags, see below */
-	unsigned int flags;
-};
-
-struct cfq_rq {
-	struct rb_node rb_node;
-	sector_t rb_key;
-	struct request *request;
-	struct hlist_node hash;
-
-	struct cfq_queue *cfq_queue;
-	struct cfq_io_context *io_context;
-
-	unsigned int crq_flags;
-};
-
-enum cfqq_state_flags {
-	CFQ_CFQQ_FLAG_on_rr = 0,
-	CFQ_CFQQ_FLAG_wait_request,
-	CFQ_CFQQ_FLAG_must_alloc,
-	CFQ_CFQQ_FLAG_must_alloc_slice,
-	CFQ_CFQQ_FLAG_must_dispatch,
-	CFQ_CFQQ_FLAG_fifo_expire,
-	CFQ_CFQQ_FLAG_idle_window,
-	CFQ_CFQQ_FLAG_prio_changed,
-	CFQ_CFQQ_FLAG_expired,
-};
-
-#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_alloc);
-CFQ_CFQQ_FNS(must_alloc_slice);
-CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
-CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(expired);
-#undef CFQ_CFQQ_FNS
-
-enum cfq_rq_state_flags {
-	CFQ_CRQ_FLAG_is_sync = 0,
-};
-
-#define CFQ_CRQ_FNS(name)						\
-static inline void cfq_mark_crq_##name(struct cfq_rq *crq)		\
-{									\
-	crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name);			\
-}									\
-static inline void cfq_clear_crq_##name(struct cfq_rq *crq)		\
-{									\
-	crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name);			\
-}									\
-static inline int cfq_crq_##name(const struct cfq_rq *crq)		\
-{									\
-	return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0;	\
-}
-
-CFQ_CRQ_FNS(is_sync);
-#undef CFQ_CRQ_FNS
-
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
-static void cfq_put_cfqd(struct cfq_data *cfqd);
-
-#define process_sync(tsk)	((tsk)->flags & PF_SYNCWRITE)
-
-/*
- * lots of deadline iosched dupes, can be abstracted later...
- */
-static inline void cfq_del_crq_hash(struct cfq_rq *crq)
-{
-	hlist_del_init(&crq->hash);
-}
-
-static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
-{
-	const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
-
-	hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
-}
-
-static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
-{
-	struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)];
-	struct hlist_node *entry, *next;
-
-	hlist_for_each_safe(entry, next, hash_list) {
-		struct cfq_rq *crq = list_entry_hash(entry);
-		struct request *__rq = crq->request;
-
-		if (!rq_mergeable(__rq)) {
-			cfq_del_crq_hash(crq);
-			continue;
-		}
-
-		if (rq_hash_key(__rq) == offset)
-			return __rq;
-	}
-
-	return NULL;
-}
-
-/*
- * 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->rq_in_driver && cfqd->busy_queues)
-		kblockd_schedule_work(&cfqd->unplug_work);
-}
-
-static int cfq_queue_empty(request_queue_t *q)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	return !cfqd->busy_queues;
-}
-
-/*
- * Lifted from AS - choose which of crq1 and crq2 that is best served now.
- * We choose the request that is closest to the head right now. Distance
- * behind the head are penalized and only allowed to a certain extent.
- */
-static struct cfq_rq *
-cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
-{
-	sector_t last, s1, s2, d1 = 0, d2 = 0;
-	int r1_wrap = 0, r2_wrap = 0;	/* requests are behind the disk head */
-	unsigned long back_max;
-
-	if (crq1 == NULL || crq1 == crq2)
-		return crq2;
-	if (crq2 == NULL)
-		return crq1;
-
-	if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
-		return crq1;
-	else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
-		return crq2;
-
-	s1 = crq1->request->sector;
-	s2 = crq2->request->sector;
-
-	last = cfqd->last_sector;
-
-	/*
-	 * 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
-		r1_wrap = 1;
-
-	if (s2 >= last)
-		d2 = s2 - last;
-	else if (s2 + back_max >= last)
-		d2 = (last - s2) * cfqd->cfq_back_penalty;
-	else
-		r2_wrap = 1;
-
-	/* Found required data */
-	if (!r1_wrap && r2_wrap)
-		return crq1;
-	else if (!r2_wrap && r1_wrap)
-		return crq2;
-	else if (r1_wrap && r2_wrap) {
-		/* both behind the head */
-		if (s1 <= s2)
-			return crq1;
-		else
-			return crq2;
-	}
-
-	/* Both requests in front of the head */
-	if (d1 < d2)
-		return crq1;
-	else if (d2 < d1)
-		return crq2;
-	else {
-		if (s1 >= s2)
-			return crq1;
-		else
-			return crq2;
-	}
-}
-
-/*
- * would be nice to take fifo expire time into account as well
- */
-static struct cfq_rq *
-cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		  struct cfq_rq *last)
-{
-	struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
-	struct rb_node *rbnext, *rbprev;
-
-	if (!(rbnext = rb_next(&last->rb_node))) {
-		rbnext = rb_first(&cfqq->sort_list);
-		if (rbnext == &last->rb_node)
-			rbnext = NULL;
-	}
-
-	rbprev = rb_prev(&last->rb_node);
-
-	if (rbprev)
-		crq_prev = rb_entry_crq(rbprev);
-	if (rbnext)
-		crq_next = rb_entry_crq(rbnext);
-
-	return cfq_choose_req(cfqd, crq_next, crq_prev);
-}
-
-static void cfq_update_next_crq(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	if (cfqq->next_crq == crq)
-		cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
-}
-
-static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct list_head *list, *entry;
-
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
-	list_del(&cfqq->cfq_list);
-
-	if (cfq_class_rt(cfqq))
-		list = &cfqd->cur_rr;
-	else if (cfq_class_idle(cfqq))
-		list = &cfqd->idle_rr;
-	else {
-		/*
-		 * if cfqq has requests in flight, don't allow it to be
-		 * found in cfq_set_active_queue before it has finished them.
-		 * this is done to increase fairness between a process that
-		 * has lots of io pending vs one that only generates one
-		 * sporadically or synchronously
-		 */
-		if (cfq_cfqq_dispatched(cfqq))
-			list = &cfqd->busy_rr;
-		else
-			list = &cfqd->rr_list[cfqq->ioprio];
-	}
-
-	/*
-	 * if queue was preempted, just add to front to be fair. busy_rr
-	 * isn't sorted.
-	 */
-	if (preempted || list == &cfqd->busy_rr) {
-		list_add(&cfqq->cfq_list, list);
-		return;
-	}
-
-	/*
-	 * sort by when queue was last serviced
-	 */
-	entry = list;
-	while ((entry = entry->prev) != list) {
-		struct cfq_queue *__cfqq = list_entry_cfqq(entry);
-
-		if (!__cfqq->service_last)
-			break;
-		if (time_before(__cfqq->service_last, cfqq->service_last))
-			break;
-	}
-
-	list_add(&cfqq->cfq_list, entry);
-}
-
-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static inline void
-cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-	cfq_mark_cfqq_on_rr(cfqq);
-	cfqd->busy_queues++;
-
-	cfq_resort_rr_list(cfqq, 0);
-}
-
-static inline void
-cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-	cfq_clear_cfqq_on_rr(cfqq);
-	list_move(&cfqq->cfq_list, &cfqd->empty_list);
-
-	BUG_ON(!cfqd->busy_queues);
-	cfqd->busy_queues--;
-}
-
-/*
- * rb tree support functions
- */
-static inline void cfq_del_crq_rb(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	const int sync = cfq_crq_is_sync(crq);
-
-	BUG_ON(!cfqq->queued[sync]);
-	cfqq->queued[sync]--;
-
-	cfq_update_next_crq(crq);
-
-	rb_erase(&crq->rb_node, &cfqq->sort_list);
-	RB_CLEAR_COLOR(&crq->rb_node);
-
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
-		cfq_del_cfqq_rr(cfqd, cfqq);
-}
-
-static struct cfq_rq *
-__cfq_add_crq_rb(struct cfq_rq *crq)
-{
-	struct rb_node **p = &crq->cfq_queue->sort_list.rb_node;
-	struct rb_node *parent = NULL;
-	struct cfq_rq *__crq;
-
-	while (*p) {
-		parent = *p;
-		__crq = rb_entry_crq(parent);
-
-		if (crq->rb_key < __crq->rb_key)
-			p = &(*p)->rb_left;
-		else if (crq->rb_key > __crq->rb_key)
-			p = &(*p)->rb_right;
-		else
-			return __crq;
-	}
-
-	rb_link_node(&crq->rb_node, parent, p);
-	return NULL;
-}
-
-static void cfq_add_crq_rb(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *rq = crq->request;
-	struct cfq_rq *__alias;
-
-	crq->rb_key = rq_rb_key(rq);
-	cfqq->queued[cfq_crq_is_sync(crq)]++;
-
-	/*
-	 * looks a little odd, but the first insert might return an alias.
-	 * if that happens, put the alias on the dispatch list
-	 */
-	while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
-		cfq_dispatch_insert(cfqd->queue, __alias);
-
-	rb_insert_color(&crq->rb_node, &cfqq->sort_list);
-
-	if (!cfq_cfqq_on_rr(cfqq))
-		cfq_add_cfqq_rr(cfqd, cfqq);
-
-	/*
-	 * check if this request is a better next-serve candidate
-	 */
-	cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
-}
-
-static inline void
-cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
-{
-	rb_erase(&crq->rb_node, &cfqq->sort_list);
-	cfqq->queued[cfq_crq_is_sync(crq)]--;
-
-	cfq_add_crq_rb(crq);
-}
-
-static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
-
-{
-	struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY);
-	struct rb_node *n;
-
-	if (!cfqq)
-		goto out;
-
-	n = cfqq->sort_list.rb_node;
-	while (n) {
-		struct cfq_rq *crq = rb_entry_crq(n);
-
-		if (sector < crq->rb_key)
-			n = n->rb_left;
-		else if (sector > crq->rb_key)
-			n = n->rb_right;
-		else
-			return crq->request;
-	}
-
-out:
-	return NULL;
-}
-
-static void cfq_activate_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	cfqd->rq_in_driver++;
-}
-
-static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	cfqd->rq_in_driver--;
-}
-
-static void cfq_remove_request(struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-
-	list_del_init(&rq->queuelist);
-	cfq_del_crq_rb(crq);
-	cfq_del_crq_hash(crq);
-}
-
-static int
-cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct request *__rq;
-	int ret;
-
-	__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
-	if (__rq && elv_rq_merge_ok(__rq, bio)) {
-		ret = ELEVATOR_BACK_MERGE;
-		goto out;
-	}
-
-	__rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
-	if (__rq && elv_rq_merge_ok(__rq, bio)) {
-		ret = ELEVATOR_FRONT_MERGE;
-		goto out;
-	}
-
-	return ELEVATOR_NO_MERGE;
-out:
-	*req = __rq;
-	return ret;
-}
-
-static void cfq_merged_request(request_queue_t *q, struct request *req)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(req);
-
-	cfq_del_crq_hash(crq);
-	cfq_add_crq_hash(cfqd, crq);
-
-	if (rq_rb_key(req) != crq->rb_key) {
-		struct cfq_queue *cfqq = crq->cfq_queue;
-
-		cfq_update_next_crq(crq);
-		cfq_reposition_crq_rb(cfqq, crq);
-	}
-}
-
-static void
-cfq_merged_requests(request_queue_t *q, struct request *rq,
-		    struct request *next)
-{
-	cfq_merged_request(q, rq);
-
-	/*
-	 * reposition in fifo if next is older than rq
-	 */
-	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
-	    time_before(next->start_time, rq->start_time))
-		list_move(&rq->queuelist, &next->queuelist);
-
-	cfq_remove_request(next);
-}
-
-static inline void
-__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		/*
-		 * stop potential idle class queues waiting service
-		 */
-		del_timer(&cfqd->idle_class_timer);
-
-		cfqq->slice_start = jiffies;
-		cfqq->slice_end = 0;
-		cfqq->slice_left = 0;
-		cfq_clear_cfqq_must_alloc_slice(cfqq);
-		cfq_clear_cfqq_fifo_expire(cfqq);
-		cfq_clear_cfqq_expired(cfqq);
-	}
-
-	cfqd->active_queue = cfqq;
-}
-
-/*
- * 0
- * 0,1
- * 0,1,2
- * 0,1,2,3
- * 0,1,2,3,4
- * 0,1,2,3,4,5
- * 0,1,2,3,4,5,6
- * 0,1,2,3,4,5,6,7
- */
-static int cfq_get_next_prio_level(struct cfq_data *cfqd)
-{
-	int prio, wrap;
-
-	prio = -1;
-	wrap = 0;
-	do {
-		int p;
-
-		for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
-			if (!list_empty(&cfqd->rr_list[p])) {
-				prio = p;
-				break;
-			}
-		}
-
-		if (prio != -1)
-			break;
-		cfqd->cur_prio = 0;
-		if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
-			cfqd->cur_end_prio = 0;
-			if (wrap)
-				break;
-			wrap = 1;
-		}
-	} while (1);
-
-	if (unlikely(prio == -1))
-		return -1;
-
-	BUG_ON(prio >= CFQ_PRIO_LISTS);
-
-	list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
-
-	cfqd->cur_prio = prio + 1;
-	if (cfqd->cur_prio > cfqd->cur_end_prio) {
-		cfqd->cur_end_prio = cfqd->cur_prio;
-		cfqd->cur_prio = 0;
-	}
-	if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
-		cfqd->cur_prio = 0;
-		cfqd->cur_end_prio = 0;
-	}
-
-	return prio;
-}
-
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq;
-
-	/*
-	 * if current queue is expired but not done with its requests yet,
-	 * wait for that to happen
-	 */
-	if ((cfqq = cfqd->active_queue) != NULL) {
-		if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq))
-			return NULL;
-	}
-
-	/*
-	 * if current list is non-empty, grab first entry. if it is empty,
-	 * get next prio level and grab first entry then if any are spliced
-	 */
-	if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
-		cfqq = list_entry_cfqq(cfqd->cur_rr.next);
-
-	/*
-	 * if we have idle queues and no rt or be queues had pending
-	 * requests, either allow immediate service if the grace period
-	 * has passed or arm the idle grace timer
-	 */
-	if (!cfqq && !list_empty(&cfqd->idle_rr)) {
-		unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-
-		if (time_after_eq(jiffies, end))
-			cfqq = list_entry_cfqq(cfqd->idle_rr.next);
-		else
-			mod_timer(&cfqd->idle_class_timer, end);
-	}
-
-	__cfq_set_active_queue(cfqd, cfqq);
-	return 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 preempted)
-{
-	unsigned long now = jiffies;
-
-	if (cfq_cfqq_wait_request(cfqq))
-		del_timer(&cfqd->idle_slice_timer);
-
-	if (!preempted && !cfq_cfqq_dispatched(cfqq))
-		cfqq->service_last = now;
-
-	cfq_clear_cfqq_must_dispatch(cfqq);
-	cfq_clear_cfqq_wait_request(cfqq);
-
-	/*
-	 * store what was left of this slice, if the queue idled out
-	 * or was preempted
-	 */
-	if (time_after(now, cfqq->slice_end))
-		cfqq->slice_left = now - cfqq->slice_end;
-	else
-		cfqq->slice_left = 0;
-
-	if (cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, preempted);
-
-	if (cfqq == cfqd->active_queue)
-		cfqd->active_queue = NULL;
-
-	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->ioc);
-		cfqd->active_cic = NULL;
-	}
-
-	cfqd->dispatch_slice = 0;
-}
-
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfqq) {
-		/*
-		 * use deferred expiry, if there are requests in progress as
-		 * not to disturb the slice of the next queue
-		 */
-		if (cfq_cfqq_dispatched(cfqq))
-			cfq_mark_cfqq_expired(cfqq);
-		else
-			__cfq_slice_expired(cfqd, cfqq, preempted);
-	}
-}
-
-static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-
-{
-	WARN_ON(!RB_EMPTY(&cfqq->sort_list));
-	WARN_ON(cfqq != cfqd->active_queue);
-
-	/*
-	 * idle is disabled, either manually or by past process history
-	 */
-	if (!cfqd->cfq_slice_idle)
-		return 0;
-	if (!cfq_cfqq_idle_window(cfqq))
-		return 0;
-	/*
-	 * task has exited, don't wait
-	 */
-	if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
-		return 0;
-
-	cfq_mark_cfqq_must_dispatch(cfqq);
-	cfq_mark_cfqq_wait_request(cfqq);
-
-	if (!timer_pending(&cfqd->idle_slice_timer)) {
-		unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
-
-		cfqd->idle_slice_timer.expires = jiffies + slice_left;
-		add_timer(&cfqd->idle_slice_timer);
-	}
-
-	return 1;
-}
-
-static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
-	cfq_remove_request(crq->request);
-	cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
-	elv_dispatch_sort(q, crq->request);
-}
-
-/*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
-static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *rq;
-	struct cfq_rq *crq;
-
-	if (cfq_cfqq_fifo_expire(cfqq))
-		return NULL;
-
-	if (!list_empty(&cfqq->fifo)) {
-		int fifo = cfq_cfqq_class_sync(cfqq);
-
-		crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
-		rq = crq->request;
-		if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
-			cfq_mark_cfqq_fifo_expire(cfqq);
-			return crq;
-		}
-	}
-
-	return NULL;
-}
-
-/*
- * 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_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
-
-	WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
-
-	return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - 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;
-}
-
-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 + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
-}
-
-/*
- * get next queue for service
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
-{
-	unsigned long now = jiffies;
-	struct cfq_queue *cfqq;
-
-	cfqq = cfqd->active_queue;
-	if (!cfqq)
-		goto new_queue;
-
-	if (cfq_cfqq_expired(cfqq))
-		goto new_queue;
-
-	/*
-	 * slice has expired
-	 */
-	if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
-		goto expire;
-
-	/*
-	 * if queue has requests, dispatch one. if not, check if
-	 * enough slice is left to wait for one
-	 */
-	if (!RB_EMPTY(&cfqq->sort_list))
-		goto keep_queue;
-	else if (!force && cfq_cfqq_class_sync(cfqq) &&
-		 time_before(now, cfqq->slice_end)) {
-		if (cfq_arm_slice_timer(cfqd, cfqq))
-			return NULL;
-	}
-
-expire:
-	cfq_slice_expired(cfqd, 0);
-new_queue:
-	cfqq = cfq_set_active_queue(cfqd);
-keep_queue:
-	return cfqq;
-}
-
-static int
-__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			int max_dispatch)
-{
-	int dispatched = 0;
-
-	BUG_ON(RB_EMPTY(&cfqq->sort_list));
-
-	do {
-		struct cfq_rq *crq;
-
-		/*
-		 * follow expired path, else get first next available
-		 */
-		if ((crq = cfq_check_fifo(cfqq)) == NULL)
-			crq = cfqq->next_crq;
-
-		/*
-		 * finally, insert request into driver dispatch list
-		 */
-		cfq_dispatch_insert(cfqd->queue, crq);
-
-		cfqd->dispatch_slice++;
-		dispatched++;
-
-		if (!cfqd->active_cic) {
-			atomic_inc(&crq->io_context->ioc->refcount);
-			cfqd->active_cic = crq->io_context;
-		}
-
-		if (RB_EMPTY(&cfqq->sort_list))
-			break;
-
-	} while (dispatched < max_dispatch);
-
-	/*
-	 * if slice end isn't set yet, set it. if at least one request was
-	 * sync, use the sync time slice value
-	 */
-	if (!cfqq->slice_end)
-		cfq_set_prio_slice(cfqd, cfqq);
-
-	/*
-	 * expire an async queue immediately if it has used up its slice. idle
-	 * queue always expire after 1 dispatch round.
-	 */
-	if ((!cfq_cfqq_sync(cfqq) &&
-	    cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-	    cfq_class_idle(cfqq))
-		cfq_slice_expired(cfqd, 0);
-
-	return dispatched;
-}
-
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq;
-
-	if (!cfqd->busy_queues)
-		return 0;
-
-	cfqq = cfq_select_queue(cfqd, force);
-	if (cfqq) {
-		int max_dispatch;
-
-		/*
-		 * if idle window is disabled, allow queue buildup
-		 */
-		if (!cfq_cfqq_idle_window(cfqq) &&
-		    cfqd->rq_in_driver >= cfqd->cfq_max_depth)
-			return 0;
-
-		cfq_clear_cfqq_must_dispatch(cfqq);
-		cfq_clear_cfqq_wait_request(cfqq);
-		del_timer(&cfqd->idle_slice_timer);
-
-		if (!force) {
-			max_dispatch = cfqd->cfq_quantum;
-			if (cfq_class_idle(cfqq))
-				max_dispatch = 1;
-		} else
-			max_dispatch = INT_MAX;
-
-		return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
-	}
-
-	return 0;
-}
-
-/*
- * task holds one reference to the queue, dropped when task exits. each crq
- * in-flight on this queue also holds a reference, dropped when crq is freed.
- *
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-
-	BUG_ON(atomic_read(&cfqq->ref) <= 0);
-
-	if (!atomic_dec_and_test(&cfqq->ref))
-		return;
-
-	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);
-	}
-
-	cfq_put_cfqd(cfqq->cfqd);
-
-	/*
-	 * it's on the empty list and still hashed
-	 */
-	list_del(&cfqq->cfq_list);
-	hlist_del(&cfqq->cfq_hash);
-	kmem_cache_free(cfq_pool, cfqq);
-}
-
-static inline struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
-		    const int hashval)
-{
-	struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
-	struct hlist_node *entry, *next;
-
-	hlist_for_each_safe(entry, next, hash_list) {
-		struct cfq_queue *__cfqq = list_entry_qhash(entry);
-		const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio);
-
-		if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY))
-			return __cfqq;
-	}
-
-	return NULL;
-}
-
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
-{
-	return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
-}
-
-static void cfq_free_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_io_context *__cic;
-	struct list_head *entry, *next;
-
-	list_for_each_safe(entry, next, &cic->list) {
-		__cic = list_entry(entry, struct cfq_io_context, list);
-		kmem_cache_free(cfq_ioc_pool, __cic);
-	}
-
-	kmem_cache_free(cfq_ioc_pool, cic);
-}
-
-/*
- * Called with interrupts disabled
- */
-static void cfq_exit_single_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_data *cfqd = cic->cfqq->cfqd;
-	request_queue_t *q = cfqd->queue;
-
-	WARN_ON(!irqs_disabled());
-
-	spin_lock(q->queue_lock);
-
-	if (unlikely(cic->cfqq == cfqd->active_queue)) {
-		__cfq_slice_expired(cfqd, cic->cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
-	}
-
-	cfq_put_queue(cic->cfqq);
-	cic->cfqq = NULL;
-	spin_unlock(q->queue_lock);
-}
-
-/*
- * Another task may update the task cic list, if it is doing a queue lookup
- * on its behalf. cfq_cic_lock excludes such concurrent updates
- */
-static void cfq_exit_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_io_context *__cic;
-	struct list_head *entry;
-	unsigned long flags;
-
-	local_irq_save(flags);
-
-	/*
-	 * put the reference this task is holding to the various queues
-	 */
-	list_for_each(entry, &cic->list) {
-		__cic = list_entry(entry, struct cfq_io_context, list);
-		cfq_exit_single_io_context(__cic);
-	}
-
-	cfq_exit_single_io_context(cic);
-	local_irq_restore(flags);
-}
-
-static struct cfq_io_context *
-cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
-	struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
-
-	if (cic) {
-		INIT_LIST_HEAD(&cic->list);
-		cic->cfqq = NULL;
-		cic->key = NULL;
-		cic->last_end_request = jiffies;
-		cic->ttime_total = 0;
-		cic->ttime_samples = 0;
-		cic->ttime_mean = 0;
-		cic->dtor = cfq_free_io_context;
-		cic->exit = cfq_exit_io_context;
-	}
-
-	return cic;
-}
-
-static void cfq_init_prio_data(struct cfq_queue *cfqq)
-{
-	struct task_struct *tsk = current;
-	int ioprio_class;
-
-	if (!cfq_cfqq_prio_changed(cfqq))
-		return;
-
-	ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
-	switch (ioprio_class) {
-		default:
-			printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
-		case IOPRIO_CLASS_NONE:
-			/*
-			 * no prio set, place us in the middle of the BE classes
-			 */
-			cfqq->ioprio = task_nice_ioprio(tsk);
-			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-			break;
-		case IOPRIO_CLASS_RT:
-			cfqq->ioprio = task_ioprio(tsk);
-			cfqq->ioprio_class = IOPRIO_CLASS_RT;
-			break;
-		case IOPRIO_CLASS_BE:
-			cfqq->ioprio = task_ioprio(tsk);
-			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;
-
-	if (cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, 0);
-
-	cfq_clear_cfqq_prio_changed(cfqq);
-}
-
-static inline void changed_ioprio(struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		struct cfq_data *cfqd = cfqq->cfqd;
-
-		spin_lock(cfqd->queue->queue_lock);
-		cfq_mark_cfqq_prio_changed(cfqq);
-		cfq_init_prio_data(cfqq);
-		spin_unlock(cfqd->queue->queue_lock);
-	}
-}
-
-/*
- * callback from sys_ioprio_set, irqs are disabled
- */
-static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
-{
-	struct cfq_io_context *cic = ioc->cic;
-
-	changed_ioprio(cic->cfqq);
-
-	list_for_each_entry(cic, &cic->list, list)
-		changed_ioprio(cic->cfqq);
-
-	return 0;
-}
-
-static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio,
-	      gfp_t gfp_mask)
-{
-	const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
-	struct cfq_queue *cfqq, *new_cfqq = NULL;
-
-retry:
-	cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
-
-	if (!cfqq) {
-		if (new_cfqq) {
-			cfqq = new_cfqq;
-			new_cfqq = NULL;
-		} else if (gfp_mask & __GFP_WAIT) {
-			spin_unlock_irq(cfqd->queue->queue_lock);
-			new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
-			spin_lock_irq(cfqd->queue->queue_lock);
-			goto retry;
-		} else {
-			cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
-			if (!cfqq)
-				goto out;
-		}
-
-		memset(cfqq, 0, sizeof(*cfqq));
-
-		INIT_HLIST_NODE(&cfqq->cfq_hash);
-		INIT_LIST_HEAD(&cfqq->cfq_list);
-		RB_CLEAR_ROOT(&cfqq->sort_list);
-		INIT_LIST_HEAD(&cfqq->fifo);
-
-		cfqq->key = key;
-		hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
-		atomic_set(&cfqq->ref, 0);
-		cfqq->cfqd = cfqd;
-		atomic_inc(&cfqd->ref);
-		cfqq->service_last = 0;
-		/*
-		 * set ->slice_left to allow preemption for a new process
-		 */
-		cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
-		cfq_mark_cfqq_idle_window(cfqq);
-		cfq_mark_cfqq_prio_changed(cfqq);
-		cfq_init_prio_data(cfqq);
-	}
-
-	if (new_cfqq)
-		kmem_cache_free(cfq_pool, new_cfqq);
-
-	atomic_inc(&cfqq->ref);
-out:
-	WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
-	return cfqq;
-}
-
-/*
- * 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. Note that caller is holding a reference to
- * cfqq, so we don't need to worry about it disappearing
- */
-static struct cfq_io_context *
-cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask)
-{
-	struct io_context *ioc = NULL;
-	struct cfq_io_context *cic;
-
-	might_sleep_if(gfp_mask & __GFP_WAIT);
-
-	ioc = get_io_context(gfp_mask);
-	if (!ioc)
-		return NULL;
-
-	if ((cic = ioc->cic) == NULL) {
-		cic = cfq_alloc_io_context(cfqd, gfp_mask);
-
-		if (cic == NULL)
-			goto err;
-
-		/*
-		 * manually increment generic io_context usage count, it
-		 * cannot go away since we are already holding one ref to it
-		 */
-		ioc->cic = cic;
-		ioc->set_ioprio = cfq_ioc_set_ioprio;
-		cic->ioc = ioc;
-		cic->key = cfqd;
-		atomic_inc(&cfqd->ref);
-	} else {
-		struct cfq_io_context *__cic;
-
-		/*
-		 * the first cic on the list is actually the head itself
-		 */
-		if (cic->key == cfqd)
-			goto out;
-
-		/*
-		 * cic exists, check if we already are there. linear search
-		 * should be ok here, the list will usually not be more than
-		 * 1 or a few entries long
-		 */
-		list_for_each_entry(__cic, &cic->list, list) {
-			/*
-			 * this process is already holding a reference to
-			 * this queue, so no need to get one more
-			 */
-			if (__cic->key == cfqd) {
-				cic = __cic;
-				goto out;
-			}
-		}
-
-		/*
-		 * nope, process doesn't have a cic assoicated with this
-		 * cfqq yet. get a new one and add to list
-		 */
-		__cic = cfq_alloc_io_context(cfqd, gfp_mask);
-		if (__cic == NULL)
-			goto err;
-
-		__cic->ioc = ioc;
-		__cic->key = cfqd;
-		atomic_inc(&cfqd->ref);
-		list_add(&__cic->list, &cic->list);
-		cic = __cic;
-	}
-
-out:
-	return cic;
-err:
-	put_io_context(ioc);
-	return NULL;
-}
-
-static void
-cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
-{
-	unsigned long elapsed, ttime;
-
-	/*
-	 * if this context already has stuff queued, thinktime is from
-	 * last queue not last end
-	 */
-#if 0
-	if (time_after(cic->last_end_request, cic->last_queue))
-		elapsed = jiffies - cic->last_end_request;
-	else
-		elapsed = jiffies - cic->last_queue;
-#else
-		elapsed = jiffies - cic->last_end_request;
-#endif
-
-	ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
-
-	cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
-	cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
-	cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
-}
-
-#define sample_valid(samples)	((samples) > 80)
-
-/*
- * 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_context *cic)
-{
-	int enable_idle = cfq_cfqq_idle_window(cfqq);
-
-	if (!cic->ioc->task || !cfqd->cfq_slice_idle)
-		enable_idle = 0;
-	else if (sample_valid(cic->ttime_samples)) {
-		if (cic->ttime_mean > cfqd->cfq_slice_idle)
-			enable_idle = 0;
-		else
-			enable_idle = 1;
-	}
-
-	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 int
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-		   struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfq_class_idle(new_cfqq))
-		return 0;
-
-	if (!cfqq)
-		return 1;
-
-	if (cfq_class_idle(cfqq))
-		return 1;
-	if (!cfq_cfqq_wait_request(new_cfqq))
-		return 0;
-	/*
-	 * if it doesn't have slice left, forget it
-	 */
-	if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
-		return 0;
-	if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
-		return 1;
-
-	return 0;
-}
-
-/*
- * 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)
-{
-	struct cfq_queue *__cfqq, *next;
-
-	list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
-		cfq_resort_rr_list(__cfqq, 1);
-
-	if (!cfqq->slice_left)
-		cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
-	cfqq->slice_end = cfqq->slice_left + jiffies;
-	__cfq_slice_expired(cfqd, cfqq, 1);
-	__cfq_set_active_queue(cfqd, cfqq);
-}
-
-/*
- * should really be a ll_rw_blk.c helper
- */
-static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	request_queue_t *q = cfqd->queue;
-
-	if (!blk_queue_plugged(q))
-		q->request_fn(q);
-	else
-		__generic_unplug_device(q);
-}
-
-/*
- * Called when a new fs request (crq) is added (to cfqq). Check if there's
- * something we should do about it
- */
-static void
-cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		 struct cfq_rq *crq)
-{
-	struct cfq_io_context *cic;
-
-	cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
-
-	/*
-	 * we never wait for an async request and we don't allow preemption
-	 * of an async request. so just return early
-	 */
-	if (!cfq_crq_is_sync(crq))
-		return;
-
-	cic = crq->io_context;
-
-	cfq_update_io_thinktime(cfqd, cic);
-	cfq_update_idle_window(cfqd, cfqq, cic);
-
-	cic->last_queue = jiffies;
-
-	if (cfqq == cfqd->active_queue) {
-		/*
-		 * if we are waiting for a request for this queue, let it rip
-		 * immediately and flag that we must not expire this queue
-		 * just now
-		 */
-		if (cfq_cfqq_wait_request(cfqq)) {
-			cfq_mark_cfqq_must_dispatch(cfqq);
-			del_timer(&cfqd->idle_slice_timer);
-			cfq_start_queueing(cfqd, cfqq);
-		}
-	} else if (cfq_should_preempt(cfqd, cfqq, crq)) {
-		/*
-		 * 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
-		 */
-		cfq_preempt_queue(cfqd, cfqq);
-		cfq_mark_cfqq_must_dispatch(cfqq);
-		cfq_start_queueing(cfqd, cfqq);
-	}
-}
-
-static void cfq_insert_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	cfq_init_prio_data(cfqq);
-
-	cfq_add_crq_rb(crq);
-
-	list_add_tail(&rq->queuelist, &cfqq->fifo);
-
-	if (rq_mergeable(rq))
-		cfq_add_crq_hash(cfqd, crq);
-
-	cfq_crq_enqueued(cfqd, cfqq, crq);
-}
-
-static void cfq_completed_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	const int sync = cfq_crq_is_sync(crq);
-	unsigned long now;
-
-	now = jiffies;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	WARN_ON(!cfqq->on_dispatch[sync]);
-	cfqd->rq_in_driver--;
-	cfqq->on_dispatch[sync]--;
-
-	if (!cfq_class_idle(cfqq))
-		cfqd->last_end_request = now;
-
-	if (!cfq_cfqq_dispatched(cfqq)) {
-		if (cfq_cfqq_on_rr(cfqq)) {
-			cfqq->service_last = now;
-			cfq_resort_rr_list(cfqq, 0);
-		}
-		if (cfq_cfqq_expired(cfqq)) {
-			__cfq_slice_expired(cfqd, cfqq, 0);
-			cfq_schedule_dispatch(cfqd);
-		}
-	}
-
-	if (cfq_crq_is_sync(crq))
-		crq->io_context->last_end_request = now;
-}
-
-static struct request *
-cfq_former_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct rb_node *rbprev = rb_prev(&crq->rb_node);
-
-	if (rbprev)
-		return rb_entry_crq(rbprev)->request;
-
-	return NULL;
-}
-
-static struct request *
-cfq_latter_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct rb_node *rbnext = rb_next(&crq->rb_node);
-
-	if (rbnext)
-		return rb_entry_crq(rbnext)->request;
-
-	return NULL;
-}
-
-/*
- * we temporarily boost lower priority queues if they are holding fs exclusive
- * resources. they are boosted to normal prio (CLASS_BE/4)
- */
-static void cfq_prio_boost(struct cfq_queue *cfqq)
-{
-	const int ioprio_class = cfqq->ioprio_class;
-	const int ioprio = cfqq->ioprio;
-
-	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;
-	} 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;
-	}
-
-	/*
-	 * refile between round-robin lists if we moved the priority class
-	 */
-	if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) &&
-	    cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, 0);
-}
-
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
-{
-	if (rw == READ || process_sync(task))
-		return task->pid;
-
-	return CFQ_KEY_ASYNC;
-}
-
-static inline int
-__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		struct task_struct *task, int rw)
-{
-#if 1
-	if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
-	    !cfq_cfqq_must_alloc_slice(cfqq)) {
-		cfq_mark_cfqq_must_alloc_slice(cfqq);
-		return ELV_MQUEUE_MUST;
-	}
-
-	return ELV_MQUEUE_MAY;
-#else
-	if (!cfqq || task->flags & PF_MEMALLOC)
-		return ELV_MQUEUE_MAY;
-	if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) {
-		if (cfq_cfqq_wait_request(cfqq))
-			return ELV_MQUEUE_MUST;
-
-		/*
-		 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
-		 * can quickly flood the queue with writes from a single task
-		 */
-		if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) {
-			cfq_mark_cfqq_must_alloc_slice(cfqq);
-			return ELV_MQUEUE_MUST;
-		}
-
-		return ELV_MQUEUE_MAY;
-	}
-	if (cfq_class_idle(cfqq))
-		return ELV_MQUEUE_NO;
-	if (cfqq->allocated[rw] >= cfqd->max_queued) {
-		struct io_context *ioc = get_io_context(GFP_ATOMIC);
-		int ret = ELV_MQUEUE_NO;
-
-		if (ioc && ioc->nr_batch_requests)
-			ret = ELV_MQUEUE_MAY;
-
-		put_io_context(ioc);
-		return ret;
-	}
-
-	return ELV_MQUEUE_MAY;
-#endif
-}
-
-static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct task_struct *tsk = current;
-	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
-	 */
-	cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio);
-	if (cfqq) {
-		cfq_init_prio_data(cfqq);
-		cfq_prio_boost(cfqq);
-
-		return __cfq_may_queue(cfqd, cfqq, tsk, rw);
-	}
-
-	return ELV_MQUEUE_MAY;
-}
-
-static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct request_list *rl = &q->rq;
-
-	if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
-		smp_mb();
-		if (waitqueue_active(&rl->wait[READ]))
-			wake_up(&rl->wait[READ]);
-	}
-
-	if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) {
-		smp_mb();
-		if (waitqueue_active(&rl->wait[WRITE]))
-			wake_up(&rl->wait[WRITE]);
-	}
-}
-
-/*
- * queue lock held here
- */
-static void cfq_put_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(rq);
-
-	if (crq) {
-		struct cfq_queue *cfqq = crq->cfq_queue;
-		const int rw = rq_data_dir(rq);
-
-		BUG_ON(!cfqq->allocated[rw]);
-		cfqq->allocated[rw]--;
-
-		put_io_context(crq->io_context->ioc);
-
-		mempool_free(crq, cfqd->crq_pool);
-		rq->elevator_private = NULL;
-
-		cfq_check_waiters(q, cfqq);
-		cfq_put_queue(cfqq);
-	}
-}
-
-/*
- * Allocate cfq data structures associated with this request.
- */
-static int
-cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
-		gfp_t gfp_mask)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct task_struct *tsk = current;
-	struct cfq_io_context *cic;
-	const int rw = rq_data_dir(rq);
-	pid_t key = cfq_queue_pid(tsk, rw);
-	struct cfq_queue *cfqq;
-	struct cfq_rq *crq;
-	unsigned long flags;
-
-	might_sleep_if(gfp_mask & __GFP_WAIT);
-
-	cic = cfq_get_io_context(cfqd, key, gfp_mask);
-
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	if (!cic)
-		goto queue_fail;
-
-	if (!cic->cfqq) {
-		cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask);
-		if (!cfqq)
-			goto queue_fail;
-
-		cic->cfqq = cfqq;
-	} else
-		cfqq = cic->cfqq;
-
-	cfqq->allocated[rw]++;
-	cfq_clear_cfqq_must_alloc(cfqq);
-	cfqd->rq_starved = 0;
-	atomic_inc(&cfqq->ref);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
-	if (crq) {
-		RB_CLEAR(&crq->rb_node);
-		crq->rb_key = 0;
-		crq->request = rq;
-		INIT_HLIST_NODE(&crq->hash);
-		crq->cfq_queue = cfqq;
-		crq->io_context = cic;
-
-		if (rw == READ || process_sync(tsk))
-			cfq_mark_crq_is_sync(crq);
-		else
-			cfq_clear_crq_is_sync(crq);
-
-		rq->elevator_private = crq;
-		return 0;
-	}
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	cfqq->allocated[rw]--;
-	if (!(cfqq->allocated[0] + cfqq->allocated[1]))
-		cfq_mark_cfqq_must_alloc(cfqq);
-	cfq_put_queue(cfqq);
-queue_fail:
-	if (cic)
-		put_io_context(cic->ioc);
-	/*
-	 * mark us rq allocation starved. we need to kickstart the process
-	 * ourselves if there are no pending requests that can do it for us.
-	 * that would be an extremely rare OOM situation
-	 */
-	cfqd->rq_starved = 1;
-	cfq_schedule_dispatch(cfqd);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-	return 1;
-}
-
-static void cfq_kick_queue(void *data)
-{
-	request_queue_t *q = data;
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	if (cfqd->rq_starved) {
-		struct request_list *rl = &q->rq;
-
-		/*
-		 * we aren't guaranteed to get a request after this, but we
-		 * have to be opportunistic
-		 */
-		smp_mb();
-		if (waitqueue_active(&rl->wait[READ]))
-			wake_up(&rl->wait[READ]);
-		if (waitqueue_active(&rl->wait[WRITE]))
-			wake_up(&rl->wait[WRITE]);
-	}
-
-	blk_remove_plug(q);
-	q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-/*
- * 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;
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	if ((cfqq = cfqd->active_queue) != NULL) {
-		unsigned long now = jiffies;
-
-		/*
-		 * expired
-		 */
-		if (time_after(now, cfqq->slice_end))
-			goto expire;
-
-		/*
-		 * only expire and reinvoke request handler, if there are
-		 * other queues with pending requests
-		 */
-		if (!cfqd->busy_queues) {
-			cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
-			add_timer(&cfqd->idle_slice_timer);
-			goto out_cont;
-		}
-
-		/*
-		 * not expired and it has a request pending, let it dispatch
-		 */
-		if (!RB_EMPTY(&cfqq->sort_list)) {
-			cfq_mark_cfqq_must_dispatch(cfqq);
-			goto out_kick;
-		}
-	}
-expire:
-	cfq_slice_expired(cfqd, 0);
-out_kick:
-	cfq_schedule_dispatch(cfqd);
-out_cont:
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-/*
- * Timer running if an idle class queue is waiting for service
- */
-static void cfq_idle_class_timer(unsigned long data)
-{
-	struct cfq_data *cfqd = (struct cfq_data *) data;
-	unsigned long flags, end;
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	/*
-	 * race with a non-idle queue, reset timer
-	 */
-	end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-	if (!time_after_eq(jiffies, end)) {
-		cfqd->idle_class_timer.expires = end;
-		add_timer(&cfqd->idle_class_timer);
-	} else
-		cfq_schedule_dispatch(cfqd);
-
-	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);
-	del_timer_sync(&cfqd->idle_class_timer);
-	blk_sync_queue(cfqd->queue);
-}
-
-static void cfq_put_cfqd(struct cfq_data *cfqd)
-{
-	request_queue_t *q = cfqd->queue;
-
-	if (!atomic_dec_and_test(&cfqd->ref))
-		return;
-
-	cfq_shutdown_timer_wq(cfqd);
-	blk_put_queue(q);
-
-	mempool_destroy(cfqd->crq_pool);
-	kfree(cfqd->crq_hash);
-	kfree(cfqd->cfq_hash);
-	kfree(cfqd);
-}
-
-static void cfq_exit_queue(elevator_t *e)
-{
-	struct cfq_data *cfqd = e->elevator_data;
-
-	cfq_shutdown_timer_wq(cfqd);
-	cfq_put_cfqd(cfqd);
-}
-
-static int cfq_init_queue(request_queue_t *q, elevator_t *e)
-{
-	struct cfq_data *cfqd;
-	int i;
-
-	cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL);
-	if (!cfqd)
-		return -ENOMEM;
-
-	memset(cfqd, 0, sizeof(*cfqd));
-
-	for (i = 0; i < CFQ_PRIO_LISTS; i++)
-		INIT_LIST_HEAD(&cfqd->rr_list[i]);
-
-	INIT_LIST_HEAD(&cfqd->busy_rr);
-	INIT_LIST_HEAD(&cfqd->cur_rr);
-	INIT_LIST_HEAD(&cfqd->idle_rr);
-	INIT_LIST_HEAD(&cfqd->empty_list);
-
-	cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
-	if (!cfqd->crq_hash)
-		goto out_crqhash;
-
-	cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL);
-	if (!cfqd->cfq_hash)
-		goto out_cfqhash;
-
-	cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool);
-	if (!cfqd->crq_pool)
-		goto out_crqpool;
-
-	for (i = 0; i < CFQ_MHASH_ENTRIES; i++)
-		INIT_HLIST_HEAD(&cfqd->crq_hash[i]);
-	for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
-		INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
-
-	e->elevator_data = cfqd;
-
-	cfqd->queue = q;
-	atomic_inc(&q->refcnt);
-
-	cfqd->max_queued = q->nr_requests / 4;
-	q->nr_batching = cfq_queued;
-
-	init_timer(&cfqd->idle_slice_timer);
-	cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-	cfqd->idle_slice_timer.data = (unsigned long) cfqd;
-
-	init_timer(&cfqd->idle_class_timer);
-	cfqd->idle_class_timer.function = cfq_idle_class_timer;
-	cfqd->idle_class_timer.data = (unsigned long) cfqd;
-
-	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
-
-	atomic_set(&cfqd->ref, 1);
-
-	cfqd->cfq_queued = cfq_queued;
-	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->cfq_max_depth = cfq_max_depth;
-
-	return 0;
-out_crqpool:
-	kfree(cfqd->cfq_hash);
-out_cfqhash:
-	kfree(cfqd->crq_hash);
-out_crqhash:
-	kfree(cfqd);
-	return -ENOMEM;
-}
-
-static void cfq_slab_kill(void)
-{
-	if (crq_pool)
-		kmem_cache_destroy(crq_pool);
-	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)
-{
-	crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0,
-					NULL, NULL);
-	if (!crq_pool)
-		goto fail;
-
-	cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
-					NULL, NULL);
-	if (!cfq_pool)
-		goto fail;
-
-	cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool",
-			sizeof(struct cfq_io_context), 0, 0, NULL, NULL);
-	if (!cfq_ioc_pool)
-		goto fail;
-
-	return 0;
-fail:
-	cfq_slab_kill();
-	return -ENOMEM;
-}
-
-/*
- * sysfs parts below -->
- */
-struct cfq_fs_entry {
-	struct attribute attr;
-	ssize_t (*show)(struct cfq_data *, char *);
-	ssize_t (*store)(struct cfq_data *, const char *, size_t);
-};
-
-static ssize_t
-cfq_var_show(unsigned int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-cfq_var_store(unsigned int *var, const char *page, size_t count)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtoul(p, &p, 10);
-	return count;
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
-static ssize_t __FUNC(struct cfq_data *cfqd, char *page)		\
-{									\
-	unsigned int __data = __VAR;					\
-	if (__CONV)							\
-		__data = jiffies_to_msecs(__data);			\
-	return cfq_var_show(__data, (page));				\
-}
-SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 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_max_show, cfqd->cfq_back_max, 0);
-SHOW_FUNCTION(cfq_back_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);
-SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
-static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count)	\
-{									\
-	unsigned int __data;						\
-	int ret = cfq_var_store(&__data, (page), count);		\
-	if (__data < (MIN))						\
-		__data = (MIN);						\
-	else if (__data > (MAX))					\
-		__data = (MAX);						\
-	if (__CONV)							\
-		*(__PTR) = msecs_to_jiffies(__data);			\
-	else								\
-		*(__PTR) = __data;					\
-	return ret;							\
-}
-STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 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_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
-STORE_FUNCTION(cfq_back_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);
-STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0);
-#undef STORE_FUNCTION
-
-static struct cfq_fs_entry cfq_quantum_entry = {
-	.attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_quantum_show,
-	.store = cfq_quantum_store,
-};
-static struct cfq_fs_entry cfq_queued_entry = {
-	.attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_queued_show,
-	.store = cfq_queued_store,
-};
-static struct cfq_fs_entry cfq_fifo_expire_sync_entry = {
-	.attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_fifo_expire_sync_show,
-	.store = cfq_fifo_expire_sync_store,
-};
-static struct cfq_fs_entry cfq_fifo_expire_async_entry = {
-	.attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_fifo_expire_async_show,
-	.store = cfq_fifo_expire_async_store,
-};
-static struct cfq_fs_entry cfq_back_max_entry = {
-	.attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_back_max_show,
-	.store = cfq_back_max_store,
-};
-static struct cfq_fs_entry cfq_back_penalty_entry = {
-	.attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_back_penalty_show,
-	.store = cfq_back_penalty_store,
-};
-static struct cfq_fs_entry cfq_slice_sync_entry = {
-	.attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_sync_show,
-	.store = cfq_slice_sync_store,
-};
-static struct cfq_fs_entry cfq_slice_async_entry = {
-	.attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_async_show,
-	.store = cfq_slice_async_store,
-};
-static struct cfq_fs_entry cfq_slice_async_rq_entry = {
-	.attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_async_rq_show,
-	.store = cfq_slice_async_rq_store,
-};
-static struct cfq_fs_entry cfq_slice_idle_entry = {
-	.attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_idle_show,
-	.store = cfq_slice_idle_store,
-};
-static struct cfq_fs_entry cfq_max_depth_entry = {
-	.attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_max_depth_show,
-	.store = cfq_max_depth_store,
-};
-
-static struct attribute *default_attrs[] = {
-	&cfq_quantum_entry.attr,
-	&cfq_queued_entry.attr,
-	&cfq_fifo_expire_sync_entry.attr,
-	&cfq_fifo_expire_async_entry.attr,
-	&cfq_back_max_entry.attr,
-	&cfq_back_penalty_entry.attr,
-	&cfq_slice_sync_entry.attr,
-	&cfq_slice_async_entry.attr,
-	&cfq_slice_async_rq_entry.attr,
-	&cfq_slice_idle_entry.attr,
-	&cfq_max_depth_entry.attr,
-	NULL,
-};
-
-#define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr)
-
-static ssize_t
-cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct cfq_fs_entry *entry = to_cfq(attr);
-
-	if (!entry->show)
-		return -EIO;
-
-	return entry->show(e->elevator_data, page);
-}
-
-static ssize_t
-cfq_attr_store(struct kobject *kobj, struct attribute *attr,
-	       const char *page, size_t length)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct cfq_fs_entry *entry = to_cfq(attr);
-
-	if (!entry->store)
-		return -EIO;
-
-	return entry->store(e->elevator_data, page, length);
-}
-
-static struct sysfs_ops cfq_sysfs_ops = {
-	.show	= cfq_attr_show,
-	.store	= cfq_attr_store,
-};
-
-static struct kobj_type cfq_ktype = {
-	.sysfs_ops	= &cfq_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-static struct elevator_type iosched_cfq = {
-	.ops = {
-		.elevator_merge_fn = 		cfq_merge,
-		.elevator_merged_fn =		cfq_merged_request,
-		.elevator_merge_req_fn =	cfq_merged_requests,
-		.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 =	cfq_former_request,
-		.elevator_latter_req_fn =	cfq_latter_request,
-		.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_ktype =	&cfq_ktype,
-	.elevator_name =	"cfq",
-	.elevator_owner =	THIS_MODULE,
-};
-
-static int __init cfq_init(void)
-{
-	int ret;
-
-	/*
-	 * 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;
-
-	ret = elv_register(&iosched_cfq);
-	if (ret)
-		cfq_slab_kill();
-
-	return ret;
-}
-
-static void __exit cfq_exit(void)
-{
-	elv_unregister(&iosched_cfq);
-	cfq_slab_kill();
-}
-
-module_init(cfq_init);
-module_exit(cfq_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");