[BLOCK] Move all core block layer code to new block/ directory

drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.

Signed-off-by: Jens Axboe <axboe@suse.de>

12 files changed, 0 insertions, 11437 deletions

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 51b0af1cebe..7b1cd93892b 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -409,16 +409,6 @@ config BLK_DEV_INITRD
 	  for details.
 
 
-#XXX - it makes sense to enable this only for 32-bit subarch's, not for x86_64
-#for instance.
-config LBD
-	bool "Support for Large Block Devices"
-	depends on X86 || (MIPS && 32BIT) || PPC32 || ARCH_S390_31 || SUPERH || UML
-	help
-	  Say Y here if you want to attach large (bigger than 2TB) discs to
-	  your machine, or if you want to have a raid or loopback device
-	  bigger than 2TB.  Otherwise say N.
-
 config CDROM_PKTCDVD
 	tristate "Packet writing on CD/DVD media"
 	depends on !UML
@@ -455,8 +445,6 @@ config CDROM_PKTCDVD_WCACHE
 
 source "drivers/s390/block/Kconfig"
 
-source "drivers/block/Kconfig.iosched"
-
 config ATA_OVER_ETH
 	tristate "ATA over Ethernet support"
 	depends on NET
diff --git a/drivers/block/Kconfig.iosched b/drivers/block/Kconfig.iosched
deleted file mode 100644
index 5b90d2fa63b..00000000000
--- a/drivers/block/Kconfig.iosched
+++ /dev/null
@@ -1,69 +0,0 @@
-
-menu "IO Schedulers"
-
-config IOSCHED_NOOP
-	bool
-	default y
-	---help---
-	  The no-op I/O scheduler is a minimal scheduler that does basic merging
-	  and sorting. Its main uses include non-disk based block devices like
-	  memory devices, and specialised software or hardware environments
-	  that do their own scheduling and require only minimal assistance from
-	  the kernel.
-
-config IOSCHED_AS
-	tristate "Anticipatory I/O scheduler"
-	default y
-	---help---
-	  The anticipatory I/O scheduler is the default disk scheduler. It is
-	  generally a good choice for most environments, but is quite large and
-	  complex when compared to the deadline I/O scheduler, it can also be
-	  slower in some cases especially some database loads.
-
-config IOSCHED_DEADLINE
-	tristate "Deadline I/O scheduler"
-	default y
-	---help---
-	  The deadline I/O scheduler is simple and compact, and is often as
-	  good as the anticipatory I/O scheduler, and in some database
-	  workloads, better. In the case of a single process performing I/O to
-	  a disk at any one time, its behaviour is almost identical to the
-	  anticipatory I/O scheduler and so is a good choice.
-
-config IOSCHED_CFQ
-	tristate "CFQ I/O scheduler"
-	default y
-	---help---
-	  The CFQ I/O scheduler tries to distribute bandwidth equally
-	  among all processes in the system. It should provide a fair
-	  working environment, suitable for desktop systems.
-
-choice
-	prompt "Default I/O scheduler"
-	default DEFAULT_AS
-	help
-	  Select the I/O scheduler which will be used by default for all
-	  block devices.
-
-	config DEFAULT_AS
-		bool "Anticipatory" if IOSCHED_AS
-
-	config DEFAULT_DEADLINE
-		bool "Deadline" if IOSCHED_DEADLINE
-
-	config DEFAULT_CFQ
-		bool "CFQ" if IOSCHED_CFQ
-
-	config DEFAULT_NOOP
-		bool "No-op"
-
-endchoice
-
-config DEFAULT_IOSCHED
-	string
-	default "anticipatory" if DEFAULT_AS
-	default "deadline" if DEFAULT_DEADLINE
-	default "cfq" if DEFAULT_CFQ
-	default "noop" if DEFAULT_NOOP
-
-endmenu
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 1cf09a1c065..3ec1f8df87b 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -4,21 +4,7 @@
 # 12 June 2000, Christoph Hellwig <hch@infradead.org>
 # Rewritten to use lists instead of if-statements.
 # 
-# Note : at this point, these files are compiled on all systems.
-# In the future, some of these should be built conditionally.
-#
-
-#
-# NOTE that ll_rw_blk.c must come early in linkage order - it starts the
-# kblockd threads
-#
-
-obj-y	:= elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o
 
-obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
-obj-$(CONFIG_IOSCHED_AS)	+= as-iosched.o
-obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
-obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
 obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o
 obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o
 obj-$(CONFIG_BLK_DEV_FD98)	+= floppy98.o
diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c
deleted file mode 100644
index c6744ff3829..00000000000
--- a/drivers/block/as-iosched.c
+++ /dev/null
@@ -1,1985 +0,0 @@
-/*
- *  linux/drivers/block/as-iosched.c
- *
- *  Anticipatory & deadline i/o scheduler.
- *
- *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>
- *                     Nick Piggin <piggin@cyberone.com.au>
- *
- */
-#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/interrupt.h>
-
-#define REQ_SYNC	1
-#define REQ_ASYNC	0
-
-/*
- * See Documentation/block/as-iosched.txt
- */
-
-/*
- * max time before a read is submitted.
- */
-#define default_read_expire (HZ / 8)
-
-/*
- * ditto for writes, these limits are not hard, even
- * if the disk is capable of satisfying them.
- */
-#define default_write_expire (HZ / 4)
-
-/*
- * read_batch_expire describes how long we will allow a stream of reads to
- * persist before looking to see whether it is time to switch over to writes.
- */
-#define default_read_batch_expire (HZ / 2)
-
-/*
- * write_batch_expire describes how long we want a stream of writes to run for.
- * This is not a hard limit, but a target we set for the auto-tuning thingy.
- * See, the problem is: we can send a lot of writes to disk cache / TCQ in
- * a short amount of time...
- */
-#define default_write_batch_expire (HZ / 8)
-
-/*
- * max time we may wait to anticipate a read (default around 6ms)
- */
-#define default_antic_expire ((HZ / 150) ? HZ / 150 : 1)
-
-/*
- * Keep track of up to 20ms thinktimes. We can go as big as we like here,
- * however huge values tend to interfere and not decay fast enough. A program
- * might be in a non-io phase of operation. Waiting on user input for example,
- * or doing a lengthy computation. A small penalty can be justified there, and
- * will still catch out those processes that constantly have large thinktimes.
- */
-#define MAX_THINKTIME (HZ/50UL)
-
-/* Bits in as_io_context.state */
-enum as_io_states {
-	AS_TASK_RUNNING=0,	/* Process has not exitted */
-	AS_TASK_IOSTARTED,	/* Process has started some IO */
-	AS_TASK_IORUNNING,	/* Process has completed some IO */
-};
-
-enum anticipation_status {
-	ANTIC_OFF=0,		/* Not anticipating (normal operation)	*/
-	ANTIC_WAIT_REQ,		/* The last read has not yet completed  */
-	ANTIC_WAIT_NEXT,	/* Currently anticipating a request vs
-				   last read (which has completed) */
-	ANTIC_FINISHED,		/* Anticipating but have found a candidate
-				 * or timed out */
-};
-
-struct as_data {
-	/*
-	 * run time data
-	 */
-
-	struct request_queue *q;	/* the "owner" queue */
-
-	/*
-	 * requests (as_rq s) are present on both sort_list and fifo_list
-	 */
-	struct rb_root sort_list[2];
-	struct list_head fifo_list[2];
-
-	struct as_rq *next_arq[2];	/* next in sort order */
-	sector_t last_sector[2];	/* last REQ_SYNC & REQ_ASYNC sectors */
-	struct list_head *hash;		/* request hash */
-
-	unsigned long exit_prob;	/* probability a task will exit while
-					   being waited on */
-	unsigned long new_ttime_total; 	/* mean thinktime on new proc */
-	unsigned long new_ttime_mean;
-	u64 new_seek_total;		/* mean seek on new proc */
-	sector_t new_seek_mean;
-
-	unsigned long current_batch_expires;
-	unsigned long last_check_fifo[2];
-	int changed_batch;		/* 1: waiting for old batch to end */
-	int new_batch;			/* 1: waiting on first read complete */
-	int batch_data_dir;		/* current batch REQ_SYNC / REQ_ASYNC */
-	int write_batch_count;		/* max # of reqs in a write batch */
-	int current_write_count;	/* how many requests left this batch */
-	int write_batch_idled;		/* has the write batch gone idle? */
-	mempool_t *arq_pool;
-
-	enum anticipation_status antic_status;
-	unsigned long antic_start;	/* jiffies: when it started */
-	struct timer_list antic_timer;	/* anticipatory scheduling timer */
-	struct work_struct antic_work;	/* Deferred unplugging */
-	struct io_context *io_context;	/* Identify the expected process */
-	int ioc_finished; /* IO associated with io_context is finished */
-	int nr_dispatched;
-
-	/*
-	 * settings that change how the i/o scheduler behaves
-	 */
-	unsigned long fifo_expire[2];
-	unsigned long batch_expire[2];
-	unsigned long antic_expire;
-};
-
-#define list_entry_fifo(ptr)	list_entry((ptr), struct as_rq, fifo)
-
-/*
- * per-request data.
- */
-enum arq_state {
-	AS_RQ_NEW=0,		/* New - not referenced and not on any lists */
-	AS_RQ_QUEUED,		/* In the request queue. It belongs to the
-				   scheduler */
-	AS_RQ_DISPATCHED,	/* On the dispatch list. It belongs to the
-				   driver now */
-	AS_RQ_PRESCHED,		/* Debug poisoning for requests being used */
-	AS_RQ_REMOVED,
-	AS_RQ_MERGED,
-	AS_RQ_POSTSCHED,	/* when they shouldn't be */
-};
-
-struct as_rq {
-	/*
-	 * rbtree index, key is the starting offset
-	 */
-	struct rb_node rb_node;
-	sector_t rb_key;
-
-	struct request *request;
-
-	struct io_context *io_context;	/* The submitting task */
-
-	/*
-	 * request hash, key is the ending offset (for back merge lookup)
-	 */
-	struct list_head hash;
-	unsigned int on_hash;
-
-	/*
-	 * expire fifo
-	 */
-	struct list_head fifo;
-	unsigned long expires;
-
-	unsigned int is_sync;
-	enum arq_state state;
-};
-
-#define RQ_DATA(rq)	((struct as_rq *) (rq)->elevator_private)
-
-static kmem_cache_t *arq_pool;
-
-/*
- * IO Context helper functions
- */
-
-/* Called to deallocate the as_io_context */
-static void free_as_io_context(struct as_io_context *aic)
-{
-	kfree(aic);
-}
-
-/* Called when the task exits */
-static void exit_as_io_context(struct as_io_context *aic)
-{
-	WARN_ON(!test_bit(AS_TASK_RUNNING, &aic->state));
-	clear_bit(AS_TASK_RUNNING, &aic->state);
-}
-
-static struct as_io_context *alloc_as_io_context(void)
-{
-	struct as_io_context *ret;
-
-	ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
-	if (ret) {
-		ret->dtor = free_as_io_context;
-		ret->exit = exit_as_io_context;
-		ret->state = 1 << AS_TASK_RUNNING;
-		atomic_set(&ret->nr_queued, 0);
-		atomic_set(&ret->nr_dispatched, 0);
-		spin_lock_init(&ret->lock);
-		ret->ttime_total = 0;
-		ret->ttime_samples = 0;
-		ret->ttime_mean = 0;
-		ret->seek_total = 0;
-		ret->seek_samples = 0;
-		ret->seek_mean = 0;
-	}
-
-	return ret;
-}
-
-/*
- * If the current task has no AS IO context then create one and initialise it.
- * Then take a ref on the task's io context and return it.
- */
-static struct io_context *as_get_io_context(void)
-{
-	struct io_context *ioc = get_io_context(GFP_ATOMIC);
-	if (ioc && !ioc->aic) {
-		ioc->aic = alloc_as_io_context();
-		if (!ioc->aic) {
-			put_io_context(ioc);
-			ioc = NULL;
-		}
-	}
-	return ioc;
-}
-
-static void as_put_io_context(struct as_rq *arq)
-{
-	struct as_io_context *aic;
-
-	if (unlikely(!arq->io_context))
-		return;
-
-	aic = arq->io_context->aic;
-
-	if (arq->is_sync == REQ_SYNC && aic) {
-		spin_lock(&aic->lock);
-		set_bit(AS_TASK_IORUNNING, &aic->state);
-		aic->last_end_request = jiffies;
-		spin_unlock(&aic->lock);
-	}
-
-	put_io_context(arq->io_context);
-}
-
-/*
- * the back merge hash support functions
- */
-static const int as_hash_shift = 6;
-#define AS_HASH_BLOCK(sec)	((sec) >> 3)
-#define AS_HASH_FN(sec)		(hash_long(AS_HASH_BLOCK((sec)), as_hash_shift))
-#define AS_HASH_ENTRIES		(1 << as_hash_shift)
-#define rq_hash_key(rq)		((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)	list_entry((ptr), struct as_rq, hash)
-
-static inline void __as_del_arq_hash(struct as_rq *arq)
-{
-	arq->on_hash = 0;
-	list_del_init(&arq->hash);
-}
-
-static inline void as_del_arq_hash(struct as_rq *arq)
-{
-	if (arq->on_hash)
-		__as_del_arq_hash(arq);
-}
-
-static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-	struct request *rq = arq->request;
-
-	BUG_ON(arq->on_hash);
-
-	arq->on_hash = 1;
-	list_add(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
-}
-
-/*
- * move hot entry to front of chain
- */
-static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-	struct request *rq = arq->request;
-	struct list_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
-
-	if (!arq->on_hash) {
-		WARN_ON(1);
-		return;
-	}
-
-	if (arq->hash.prev != head) {
-		list_del(&arq->hash);
-		list_add(&arq->hash, head);
-	}
-}
-
-static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
-{
-	struct list_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
-	struct list_head *entry, *next = hash_list->next;
-
-	while ((entry = next) != hash_list) {
-		struct as_rq *arq = list_entry_hash(entry);
-		struct request *__rq = arq->request;
-
-		next = entry->next;
-
-		BUG_ON(!arq->on_hash);
-
-		if (!rq_mergeable(__rq)) {
-			as_del_arq_hash(arq);
-			continue;
-		}
-
-		if (rq_hash_key(__rq) == offset)
-			return __rq;
-	}
-
-	return NULL;
-}
-
-/*
- * rb tree support functions
- */
-#define RB_NONE		(2)
-#define RB_EMPTY(root)	((root)->rb_node == NULL)
-#define ON_RB(node)	((node)->rb_color != RB_NONE)
-#define RB_CLEAR(node)	((node)->rb_color = RB_NONE)
-#define rb_entry_arq(node)	rb_entry((node), struct as_rq, rb_node)
-#define ARQ_RB_ROOT(ad, arq)	(&(ad)->sort_list[(arq)->is_sync])
-#define rq_rb_key(rq)		(rq)->sector
-
-/*
- * as_find_first_arq finds the first (lowest sector numbered) request
- * for the specified data_dir. Used to sweep back to the start of the disk
- * (1-way elevator) after we process the last (highest sector) request.
- */
-static struct as_rq *as_find_first_arq(struct as_data *ad, int data_dir)
-{
-	struct rb_node *n = ad->sort_list[data_dir].rb_node;
-
-	if (n == NULL)
-		return NULL;
-
-	for (;;) {
-		if (n->rb_left == NULL)
-			return rb_entry_arq(n);
-
-		n = n->rb_left;
-	}
-}
-
-/*
- * Add the request to the rb tree if it is unique.  If there is an alias (an
- * existing request against the same sector), which can happen when using
- * direct IO, then return the alias.
- */
-static struct as_rq *as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
-	struct rb_node **p = &ARQ_RB_ROOT(ad, arq)->rb_node;
-	struct rb_node *parent = NULL;
-	struct as_rq *__arq;
-	struct request *rq = arq->request;
-
-	arq->rb_key = rq_rb_key(rq);
-
-	while (*p) {
-		parent = *p;
-		__arq = rb_entry_arq(parent);
-
-		if (arq->rb_key < __arq->rb_key)
-			p = &(*p)->rb_left;
-		else if (arq->rb_key > __arq->rb_key)
-			p = &(*p)->rb_right;
-		else
-			return __arq;
-	}
-
-	rb_link_node(&arq->rb_node, parent, p);
-	rb_insert_color(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-
-	return NULL;
-}
-
-static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
-	if (!ON_RB(&arq->rb_node)) {
-		WARN_ON(1);
-		return;
-	}
-
-	rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-	RB_CLEAR(&arq->rb_node);
-}
-
-static struct request *
-as_find_arq_rb(struct as_data *ad, sector_t sector, int data_dir)
-{
-	struct rb_node *n = ad->sort_list[data_dir].rb_node;
-	struct as_rq *arq;
-
-	while (n) {
-		arq = rb_entry_arq(n);
-
-		if (sector < arq->rb_key)
-			n = n->rb_left;
-		else if (sector > arq->rb_key)
-			n = n->rb_right;
-		else
-			return arq->request;
-	}
-
-	return NULL;
-}
-
-/*
- * IO Scheduler proper
- */
-
-#define MAXBACK (1024 * 1024)	/*
-				 * Maximum distance the disk will go backward
-				 * for a request.
-				 */
-
-#define BACK_PENALTY	2
-
-/*
- * as_choose_req selects the preferred one of two requests of the same data_dir
- * ignoring time - eg. timeouts, which is the job of as_dispatch_request
- */
-static struct as_rq *
-as_choose_req(struct as_data *ad, struct as_rq *arq1, struct as_rq *arq2)
-{
-	int data_dir;
-	sector_t last, s1, s2, d1, d2;
-	int r1_wrap=0, r2_wrap=0;	/* requests are behind the disk head */
-	const sector_t maxback = MAXBACK;
-
-	if (arq1 == NULL || arq1 == arq2)
-		return arq2;
-	if (arq2 == NULL)
-		return arq1;
-
-	data_dir = arq1->is_sync;
-
-	last = ad->last_sector[data_dir];
-	s1 = arq1->request->sector;
-	s2 = arq2->request->sector;
-
-	BUG_ON(data_dir != arq2->is_sync);
-
-	/*
-	 * 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+maxback >= last)
-		d1 = (last - s1)*BACK_PENALTY;
-	else {
-		r1_wrap = 1;
-		d1 = 0; /* shut up, gcc */
-	}
-
-	if (s2 >= last)
-		d2 = s2 - last;
-	else if (s2+maxback >= last)
-		d2 = (last - s2)*BACK_PENALTY;
-	else {
-		r2_wrap = 1;
-		d2 = 0;
-	}
-
-	/* Found required data */
-	if (!r1_wrap && r2_wrap)
-		return arq1;
-	else if (!r2_wrap && r1_wrap)
-		return arq2;
-	else if (r1_wrap && r2_wrap) {
-		/* both behind the head */
-		if (s1 <= s2)
-			return arq1;
-		else
-			return arq2;
-	}
-
-	/* Both requests in front of the head */
-	if (d1 < d2)
-		return arq1;
-	else if (d2 < d1)
-		return arq2;
-	else {
-		if (s1 >= s2)
-			return arq1;
-		else
-			return arq2;
-	}
-}
-
-/*
- * as_find_next_arq finds the next request after @prev in elevator order.
- * this with as_choose_req form the basis for how the scheduler chooses
- * what request to process next. Anticipation works on top of this.
- */
-static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last)
-{
-	const int data_dir = last->is_sync;
-	struct as_rq *ret;
-	struct rb_node *rbnext = rb_next(&last->rb_node);
-	struct rb_node *rbprev = rb_prev(&last->rb_node);
-	struct as_rq *arq_next, *arq_prev;
-
-	BUG_ON(!ON_RB(&last->rb_node));
-
-	if (rbprev)
-		arq_prev = rb_entry_arq(rbprev);
-	else
-		arq_prev = NULL;
-
-	if (rbnext)
-		arq_next = rb_entry_arq(rbnext);
-	else {
-		arq_next = as_find_first_arq(ad, data_dir);
-		if (arq_next == last)
-			arq_next = NULL;
-	}
-
-	ret = as_choose_req(ad,	arq_next, arq_prev);
-
-	return ret;
-}
-
-/*
- * anticipatory scheduling functions follow
- */
-
-/*
- * as_antic_expired tells us when we have anticipated too long.
- * The funny "absolute difference" math on the elapsed time is to handle
- * jiffy wraps, and disks which have been idle for 0x80000000 jiffies.
- */
-static int as_antic_expired(struct as_data *ad)
-{
-	long delta_jif;
-
-	delta_jif = jiffies - ad->antic_start;
-	if (unlikely(delta_jif < 0))
-		delta_jif = -delta_jif;
-	if (delta_jif < ad->antic_expire)
-		return 0;
-
-	return 1;
-}
-
-/*
- * as_antic_waitnext starts anticipating that a nice request will soon be
- * submitted. See also as_antic_waitreq
- */
-static void as_antic_waitnext(struct as_data *ad)
-{
-	unsigned long timeout;
-
-	BUG_ON(ad->antic_status != ANTIC_OFF
-			&& ad->antic_status != ANTIC_WAIT_REQ);
-
-	timeout = ad->antic_start + ad->antic_expire;
-
-	mod_timer(&ad->antic_timer, timeout);
-
-	ad->antic_status = ANTIC_WAIT_NEXT;
-}
-
-/*
- * as_antic_waitreq starts anticipating. We don't start timing the anticipation
- * until the request that we're anticipating on has finished. This means we
- * are timing from when the candidate process wakes up hopefully.
- */
-static void as_antic_waitreq(struct as_data *ad)
-{
-	BUG_ON(ad->antic_status == ANTIC_FINISHED);
-	if (ad->antic_status == ANTIC_OFF) {
-		if (!ad->io_context || ad->ioc_finished)
-			as_antic_waitnext(ad);
-		else
-			ad->antic_status = ANTIC_WAIT_REQ;
-	}
-}
-
-/*
- * This is called directly by the functions in this file to stop anticipation.
- * We kill the timer and schedule a call to the request_fn asap.
- */
-static void as_antic_stop(struct as_data *ad)
-{
-	int status = ad->antic_status;
-
-	if (status == ANTIC_WAIT_REQ || status == ANTIC_WAIT_NEXT) {
-		if (status == ANTIC_WAIT_NEXT)
-			del_timer(&ad->antic_timer);
-		ad->antic_status = ANTIC_FINISHED;
-		/* see as_work_handler */
-		kblockd_schedule_work(&ad->antic_work);
-	}
-}
-
-/*
- * as_antic_timeout is the timer function set by as_antic_waitnext.
- */
-static void as_antic_timeout(unsigned long data)
-{
-	struct request_queue *q = (struct request_queue *)data;
-	struct as_data *ad = q->elevator->elevator_data;
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	if (ad->antic_status == ANTIC_WAIT_REQ
-			|| ad->antic_status == ANTIC_WAIT_NEXT) {
-		struct as_io_context *aic = ad->io_context->aic;
-
-		ad->antic_status = ANTIC_FINISHED;
-		kblockd_schedule_work(&ad->antic_work);
-
-		if (aic->ttime_samples == 0) {
-			/* process anticipated on has exitted or timed out*/
-			ad->exit_prob = (7*ad->exit_prob + 256)/8;
-		}
-	}
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-/*
- * as_close_req decides if one request is considered "close" to the
- * previous one issued.
- */
-static int as_close_req(struct as_data *ad, struct as_rq *arq)
-{
-	unsigned long delay;	/* milliseconds */
-	sector_t last = ad->last_sector[ad->batch_data_dir];
-	sector_t next = arq->request->sector;
-	sector_t delta; /* acceptable close offset (in sectors) */
-
-	if (ad->antic_status == ANTIC_OFF || !ad->ioc_finished)
-		delay = 0;
-	else
-		delay = ((jiffies - ad->antic_start) * 1000) / HZ;
-
-	if (delay <= 1)
-		delta = 64;
-	else if (delay <= 20 && delay <= ad->antic_expire)
-		delta = 64 << (delay-1);
-	else
-		return 1;
-
-	return (last - (delta>>1) <= next) && (next <= last + delta);
-}
-
-/*
- * as_can_break_anticipation returns true if we have been anticipating this
- * request.
- *
- * It also returns true if the process against which we are anticipating
- * submits a write - that's presumably an fsync, O_SYNC write, etc. We want to
- * dispatch it ASAP, because we know that application will not be submitting
- * any new reads.
- *
- * If the task which has submitted the request has exitted, break anticipation.
- *
- * If this task has queued some other IO, do not enter enticipation.
- */
-static int as_can_break_anticipation(struct as_data *ad, struct as_rq *arq)
-{
-	struct io_context *ioc;
-	struct as_io_context *aic;
-	sector_t s;
-
-	ioc = ad->io_context;
-	BUG_ON(!ioc);
-
-	if (arq && ioc == arq->io_context) {
-		/* request from same process */
-		return 1;
-	}
-
-	if (ad->ioc_finished && as_antic_expired(ad)) {
-		/*
-		 * In this situation status should really be FINISHED,
-		 * however the timer hasn't had the chance to run yet.
-		 */
-		return 1;
-	}
-
-	aic = ioc->aic;
-	if (!aic)
-		return 0;
-
-	if (!test_bit(AS_TASK_RUNNING, &aic->state)) {
-		/* process anticipated on has exitted */
-		if (aic->ttime_samples == 0)
-			ad->exit_prob = (7*ad->exit_prob + 256)/8;
-		return 1;
-	}
-
-	if (atomic_read(&aic->nr_queued) > 0) {
-		/* process has more requests queued */
-		return 1;
-	}
-
-	if (atomic_read(&aic->nr_dispatched) > 0) {
-		/* process has more requests dispatched */
-		return 1;
-	}
-
-	if (arq && arq->is_sync == REQ_SYNC && as_close_req(ad, arq)) {
-		/*
-		 * Found a close request that is not one of ours.
-		 *
-		 * This makes close requests from another process reset
-		 * our thinktime delay. Is generally useful when there are
-		 * two or more cooperating processes working in the same
-		 * area.
-		 */
-		spin_lock(&aic->lock);
-		aic->last_end_request = jiffies;
-		spin_unlock(&aic->lock);
-		return 1;
-	}
-
-
-	if (aic->ttime_samples == 0) {
-		if (ad->new_ttime_mean > ad->antic_expire)
-			return 1;
-		if (ad->exit_prob > 128)
-			return 1;
-	} else if (aic->ttime_mean > ad->antic_expire) {
-		/* the process thinks too much between requests */
-		return 1;
-	}
-
-	if (!arq)
-		return 0;
-
-	if (ad->last_sector[REQ_SYNC] < arq->request->sector)
-		s = arq->request->sector - ad->last_sector[REQ_SYNC];
-	else
-		s = ad->last_sector[REQ_SYNC] - arq->request->sector;
-
-	if (aic->seek_samples == 0) {
-		/*
-		 * Process has just started IO. Use past statistics to
-		 * guage success possibility
-		 */
-		if (ad->new_seek_mean > s) {
-			/* this request is better than what we're expecting */
-			return 1;
-		}
-
-	} else {
-		if (aic->seek_mean > s) {
-			/* this request is better than what we're expecting */
-			return 1;
-		}
-	}
-
-	return 0;
-}
-
-/*
- * as_can_anticipate indicates weather we should either run arq
- * or keep anticipating a better request.
- */
-static int as_can_anticipate(struct as_data *ad, struct as_rq *arq)
-{
-	if (!ad->io_context)
-		/*
-		 * Last request submitted was a write
-		 */
-		return 0;
-
-	if (ad->antic_status == ANTIC_FINISHED)
-		/*
-		 * Don't restart if we have just finished. Run the next request
-		 */
-		return 0;
-
-	if (as_can_break_anticipation(ad, arq))
-		/*
-		 * This request is a good candidate. Don't keep anticipating,
-		 * run it.
-		 */
-		return 0;
-
-	/*
-	 * OK from here, we haven't finished, and don't have a decent request!
-	 * Status is either ANTIC_OFF so start waiting,
-	 * ANTIC_WAIT_REQ so continue waiting for request to finish
-	 * or ANTIC_WAIT_NEXT so continue waiting for an acceptable request.
-	 *
-	 */
-
-	return 1;
-}
-
-static void as_update_thinktime(struct as_data *ad, struct as_io_context *aic, unsigned long ttime)
-{
-	/* fixed point: 1.0 == 1<<8 */
-	if (aic->ttime_samples == 0) {
-		ad->new_ttime_total = (7*ad->new_ttime_total + 256*ttime) / 8;
-		ad->new_ttime_mean = ad->new_ttime_total / 256;
-
-		ad->exit_prob = (7*ad->exit_prob)/8;
-	}
-	aic->ttime_samples = (7*aic->ttime_samples + 256) / 8;
-	aic->ttime_total = (7*aic->ttime_total + 256*ttime) / 8;
-	aic->ttime_mean = (aic->ttime_total + 128) / aic->ttime_samples;
-}
-
-static void as_update_seekdist(struct as_data *ad, struct as_io_context *aic, sector_t sdist)
-{
-	u64 total;
-
-	if (aic->seek_samples == 0) {
-		ad->new_seek_total = (7*ad->new_seek_total + 256*(u64)sdist)/8;
-		ad->new_seek_mean = ad->new_seek_total / 256;
-	}
-
-	/*
-	 * Don't allow the seek distance to get too large from the
-	 * odd fragment, pagein, etc
-	 */
-	if (aic->seek_samples <= 60) /* second&third seek */
-		sdist = min(sdist, (aic->seek_mean * 4) + 2*1024*1024);
-	else
-		sdist = min(sdist, (aic->seek_mean * 4)	+ 2*1024*64);
-
-	aic->seek_samples = (7*aic->seek_samples + 256) / 8;
-	aic->seek_total = (7*aic->seek_total + (u64)256*sdist) / 8;
-	total = aic->seek_total + (aic->seek_samples/2);
-	do_div(total, aic->seek_samples);
-	aic->seek_mean = (sector_t)total;
-}
-
-/*
- * as_update_iohist keeps a decaying histogram of IO thinktimes, and
- * updates @aic->ttime_mean based on that. It is called when a new
- * request is queued.
- */
-static void as_update_iohist(struct as_data *ad, struct as_io_context *aic, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-	int data_dir = arq->is_sync;
-	unsigned long thinktime;
-	sector_t seek_dist;
-
-	if (aic == NULL)
-		return;
-
-	if (data_dir == REQ_SYNC) {
-		unsigned long in_flight = atomic_read(&aic->nr_queued)
-					+ atomic_read(&aic->nr_dispatched);
-		spin_lock(&aic->lock);
-		if (test_bit(AS_TASK_IORUNNING, &aic->state) ||
-			test_bit(AS_TASK_IOSTARTED, &aic->state)) {
-			/* Calculate read -> read thinktime */
-			if (test_bit(AS_TASK_IORUNNING, &aic->state)
-							&& in_flight == 0) {
-				thinktime = jiffies - aic->last_end_request;
-				thinktime = min(thinktime, MAX_THINKTIME-1);
-			} else
-				thinktime = 0;
-			as_update_thinktime(ad, aic, thinktime);
-
-			/* Calculate read -> read seek distance */
-			if (aic->last_request_pos < rq->sector)
-				seek_dist = rq->sector - aic->last_request_pos;
-			else
-				seek_dist = aic->last_request_pos - rq->sector;
-			as_update_seekdist(ad, aic, seek_dist);
-		}
-		aic->last_request_pos = rq->sector + rq->nr_sectors;
-		set_bit(AS_TASK_IOSTARTED, &aic->state);
-		spin_unlock(&aic->lock);
-	}
-}
-
-/*
- * as_update_arq must be called whenever a request (arq) is added to
- * the sort_list. This function keeps caches up to date, and checks if the
- * request might be one we are "anticipating"
- */
-static void as_update_arq(struct as_data *ad, struct as_rq *arq)
-{
-	const int data_dir = arq->is_sync;
-
-	/* keep the next_arq cache up to date */
-	ad->next_arq[data_dir] = as_choose_req(ad, arq, ad->next_arq[data_dir]);
-
-	/*
-	 * have we been anticipating this request?
-	 * or does it come from the same process as the one we are anticipating
-	 * for?
-	 */
-	if (ad->antic_status == ANTIC_WAIT_REQ
-			|| ad->antic_status == ANTIC_WAIT_NEXT) {
-		if (as_can_break_anticipation(ad, arq))
-			as_antic_stop(ad);
-	}
-}
-
-/*
- * Gathers timings and resizes the write batch automatically
- */
-static void update_write_batch(struct as_data *ad)
-{
-	unsigned long batch = ad->batch_expire[REQ_ASYNC];
-	long write_time;
-
-	write_time = (jiffies - ad->current_batch_expires) + batch;
-	if (write_time < 0)
-		write_time = 0;
-
-	if (write_time > batch && !ad->write_batch_idled) {
-		if (write_time > batch * 3)
-			ad->write_batch_count /= 2;
-		else
-			ad->write_batch_count--;
-	} else if (write_time < batch && ad->current_write_count == 0) {
-		if (batch > write_time * 3)
-			ad->write_batch_count *= 2;