Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 0 insertions, 1723 deletions

diff --git a/ANDROID_3.4.5/drivers/md/dm-mpath.c b/ANDROID_3.4.5/drivers/md/dm-mpath.c
deleted file mode 100644
index 754f38f8..00000000
--- a/ANDROID_3.4.5/drivers/md/dm-mpath.c
+++ /dev/null
@@ -1,1723 +0,0 @@
-/*
- * Copyright (C) 2003 Sistina Software Limited.
- * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- */
-
-#include <linux/device-mapper.h>
-
-#include "dm-path-selector.h"
-#include "dm-uevent.h"
-
-#include <linux/ctype.h>
-#include <linux/init.h>
-#include <linux/mempool.h>
-#include <linux/module.h>
-#include <linux/pagemap.h>
-#include <linux/slab.h>
-#include <linux/time.h>
-#include <linux/workqueue.h>
-#include <scsi/scsi_dh.h>
-#include <linux/atomic.h>
-
-#define DM_MSG_PREFIX "multipath"
-#define DM_PG_INIT_DELAY_MSECS 2000
-#define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1)
-
-/* Path properties */
-struct pgpath {
-	struct list_head list;
-
-	struct priority_group *pg;	/* Owning PG */
-	unsigned is_active;		/* Path status */
-	unsigned fail_count;		/* Cumulative failure count */
-
-	struct dm_path path;
-	struct delayed_work activate_path;
-};
-
-#define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
-
-/*
- * Paths are grouped into Priority Groups and numbered from 1 upwards.
- * Each has a path selector which controls which path gets used.
- */
-struct priority_group {
-	struct list_head list;
-
-	struct multipath *m;		/* Owning multipath instance */
-	struct path_selector ps;
-
-	unsigned pg_num;		/* Reference number */
-	unsigned bypassed;		/* Temporarily bypass this PG? */
-
-	unsigned nr_pgpaths;		/* Number of paths in PG */
-	struct list_head pgpaths;
-};
-
-/* Multipath context */
-struct multipath {
-	struct list_head list;
-	struct dm_target *ti;
-
-	spinlock_t lock;
-
-	const char *hw_handler_name;
-	char *hw_handler_params;
-
-	unsigned nr_priority_groups;
-	struct list_head priority_groups;
-
-	wait_queue_head_t pg_init_wait;	/* Wait for pg_init completion */
-
-	unsigned pg_init_required;	/* pg_init needs calling? */
-	unsigned pg_init_in_progress;	/* Only one pg_init allowed at once */
-	unsigned pg_init_delay_retry;	/* Delay pg_init retry? */
-
-	unsigned nr_valid_paths;	/* Total number of usable paths */
-	struct pgpath *current_pgpath;
-	struct priority_group *current_pg;
-	struct priority_group *next_pg;	/* Switch to this PG if set */
-	unsigned repeat_count;		/* I/Os left before calling PS again */
-
-	unsigned queue_io;		/* Must we queue all I/O? */
-	unsigned queue_if_no_path;	/* Queue I/O if last path fails? */
-	unsigned saved_queue_if_no_path;/* Saved state during suspension */
-	unsigned pg_init_retries;	/* Number of times to retry pg_init */
-	unsigned pg_init_count;		/* Number of times pg_init called */
-	unsigned pg_init_delay_msecs;	/* Number of msecs before pg_init retry */
-
-	struct work_struct process_queued_ios;
-	struct list_head queued_ios;
-	unsigned queue_size;
-
-	struct work_struct trigger_event;
-
-	/*
-	 * We must use a mempool of dm_mpath_io structs so that we
-	 * can resubmit bios on error.
-	 */
-	mempool_t *mpio_pool;
-
-	struct mutex work_mutex;
-};
-
-/*
- * Context information attached to each bio we process.
- */
-struct dm_mpath_io {
-	struct pgpath *pgpath;
-	size_t nr_bytes;
-};
-
-typedef int (*action_fn) (struct pgpath *pgpath);
-
-#define MIN_IOS 256	/* Mempool size */
-
-static struct kmem_cache *_mpio_cache;
-
-static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
-static void process_queued_ios(struct work_struct *work);
-static void trigger_event(struct work_struct *work);
-static void activate_path(struct work_struct *work);
-
-
-/*-----------------------------------------------
- * Allocation routines
- *-----------------------------------------------*/
-
-static struct pgpath *alloc_pgpath(void)
-{
-	struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
-
-	if (pgpath) {
-		pgpath->is_active = 1;
-		INIT_DELAYED_WORK(&pgpath->activate_path, activate_path);
-	}
-
-	return pgpath;
-}
-
-static void free_pgpath(struct pgpath *pgpath)
-{
-	kfree(pgpath);
-}
-
-static struct priority_group *alloc_priority_group(void)
-{
-	struct priority_group *pg;
-
-	pg = kzalloc(sizeof(*pg), GFP_KERNEL);
-
-	if (pg)
-		INIT_LIST_HEAD(&pg->pgpaths);
-
-	return pg;
-}
-
-static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
-{
-	struct pgpath *pgpath, *tmp;
-	struct multipath *m = ti->private;
-
-	list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
-		list_del(&pgpath->list);
-		if (m->hw_handler_name)
-			scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev));
-		dm_put_device(ti, pgpath->path.dev);
-		free_pgpath(pgpath);
-	}
-}
-
-static void free_priority_group(struct priority_group *pg,
-				struct dm_target *ti)
-{
-	struct path_selector *ps = &pg->ps;
-
-	if (ps->type) {
-		ps->type->destroy(ps);
-		dm_put_path_selector(ps->type);
-	}
-
-	free_pgpaths(&pg->pgpaths, ti);
-	kfree(pg);
-}
-
-static struct multipath *alloc_multipath(struct dm_target *ti)
-{
-	struct multipath *m;
-
-	m = kzalloc(sizeof(*m), GFP_KERNEL);
-	if (m) {
-		INIT_LIST_HEAD(&m->priority_groups);
-		INIT_LIST_HEAD(&m->queued_ios);
-		spin_lock_init(&m->lock);
-		m->queue_io = 1;
-		m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
-		INIT_WORK(&m->process_queued_ios, process_queued_ios);
-		INIT_WORK(&m->trigger_event, trigger_event);
-		init_waitqueue_head(&m->pg_init_wait);
-		mutex_init(&m->work_mutex);
-		m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
-		if (!m->mpio_pool) {
-			kfree(m);
-			return NULL;
-		}
-		m->ti = ti;
-		ti->private = m;
-	}
-
-	return m;
-}
-
-static void free_multipath(struct multipath *m)
-{
-	struct priority_group *pg, *tmp;
-
-	list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
-		list_del(&pg->list);
-		free_priority_group(pg, m->ti);
-	}
-
-	kfree(m->hw_handler_name);
-	kfree(m->hw_handler_params);
-	mempool_destroy(m->mpio_pool);
-	kfree(m);
-}
-
-static int set_mapinfo(struct multipath *m, union map_info *info)
-{
-	struct dm_mpath_io *mpio;
-
-	mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
-	if (!mpio)
-		return -ENOMEM;
-
-	memset(mpio, 0, sizeof(*mpio));
-	info->ptr = mpio;
-
-	return 0;
-}
-
-static void clear_mapinfo(struct multipath *m, union map_info *info)
-{
-	struct dm_mpath_io *mpio = info->ptr;
-
-	info->ptr = NULL;
-	mempool_free(mpio, m->mpio_pool);
-}
-
-/*-----------------------------------------------
- * Path selection
- *-----------------------------------------------*/
-
-static void __pg_init_all_paths(struct multipath *m)
-{
-	struct pgpath *pgpath;
-	unsigned long pg_init_delay = 0;
-
-	m->pg_init_count++;
-	m->pg_init_required = 0;
-	if (m->pg_init_delay_retry)
-		pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ?
-						 m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS);
-	list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) {
-		/* Skip failed paths */
-		if (!pgpath->is_active)
-			continue;
-		if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path,
-				       pg_init_delay))
-			m->pg_init_in_progress++;
-	}
-}
-
-static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
-{
-	m->current_pg = pgpath->pg;
-
-	/* Must we initialise the PG first, and queue I/O till it's ready? */
-	if (m->hw_handler_name) {
-		m->pg_init_required = 1;
-		m->queue_io = 1;
-	} else {
-		m->pg_init_required = 0;
-		m->queue_io = 0;
-	}
-
-	m->pg_init_count = 0;
-}
-
-static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg,
-			       size_t nr_bytes)
-{
-	struct dm_path *path;
-
-	path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes);
-	if (!path)
-		return -ENXIO;
-
-	m->current_pgpath = path_to_pgpath(path);
-
-	if (m->current_pg != pg)
-		__switch_pg(m, m->current_pgpath);
-
-	return 0;
-}
-
-static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
-{
-	struct priority_group *pg;
-	unsigned bypassed = 1;
-
-	if (!m->nr_valid_paths)
-		goto failed;
-
-	/* Were we instructed to switch PG? */
-	if (m->next_pg) {
-		pg = m->next_pg;
-		m->next_pg = NULL;
-		if (!__choose_path_in_pg(m, pg, nr_bytes))
-			return;
-	}
-
-	/* Don't change PG until it has no remaining paths */
-	if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes))
-		return;
-
-	/*
-	 * Loop through priority groups until we find a valid path.
-	 * First time we skip PGs marked 'bypassed'.
-	 * Second time we only try the ones we skipped.
-	 */
-	do {
-		list_for_each_entry(pg, &m->priority_groups, list) {
-			if (pg->bypassed == bypassed)
-				continue;
-			if (!__choose_path_in_pg(m, pg, nr_bytes))
-				return;
-		}
-	} while (bypassed--);
-
-failed:
-	m->current_pgpath = NULL;
-	m->current_pg = NULL;
-}
-
-/*
- * Check whether bios must be queued in the device-mapper core rather
- * than here in the target.
- *
- * m->lock must be held on entry.
- *
- * If m->queue_if_no_path and m->saved_queue_if_no_path hold the
- * same value then we are not between multipath_presuspend()
- * and multipath_resume() calls and we have no need to check
- * for the DMF_NOFLUSH_SUSPENDING flag.
- */
-static int __must_push_back(struct multipath *m)
-{
-	return (m->queue_if_no_path != m->saved_queue_if_no_path &&
-		dm_noflush_suspending(m->ti));
-}
-
-static int map_io(struct multipath *m, struct request *clone,
-		  union map_info *map_context, unsigned was_queued)
-{
-	int r = DM_MAPIO_REMAPPED;
-	size_t nr_bytes = blk_rq_bytes(clone);
-	unsigned long flags;
-	struct pgpath *pgpath;
-	struct block_device *bdev;
-	struct dm_mpath_io *mpio = map_context->ptr;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	/* Do we need to select a new pgpath? */
-	if (!m->current_pgpath ||
-	    (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
-		__choose_pgpath(m, nr_bytes);
-
-	pgpath = m->current_pgpath;
-
-	if (was_queued)
-		m->queue_size--;
-
-	if ((pgpath && m->queue_io) ||
-	    (!pgpath && m->queue_if_no_path)) {
-		/* Queue for the daemon to resubmit */
-		list_add_tail(&clone->queuelist, &m->queued_ios);
-		m->queue_size++;
-		if ((m->pg_init_required && !m->pg_init_in_progress) ||
-		    !m->queue_io)
-			queue_work(kmultipathd, &m->process_queued_ios);
-		pgpath = NULL;
-		r = DM_MAPIO_SUBMITTED;
-	} else if (pgpath) {
-		bdev = pgpath->path.dev->bdev;
-		clone->q = bdev_get_queue(bdev);
-		clone->rq_disk = bdev->bd_disk;
-	} else if (__must_push_back(m))
-		r = DM_MAPIO_REQUEUE;
-	else
-		r = -EIO;	/* Failed */
-
-	mpio->pgpath = pgpath;
-	mpio->nr_bytes = nr_bytes;
-
-	if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io)
-		pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path,
-					      nr_bytes);
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return r;
-}
-
-/*
- * If we run out of usable paths, should we queue I/O or error it?
- */
-static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path,
-			    unsigned save_old_value)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (save_old_value)
-		m->saved_queue_if_no_path = m->queue_if_no_path;
-	else
-		m->saved_queue_if_no_path = queue_if_no_path;
-	m->queue_if_no_path = queue_if_no_path;
-	if (!m->queue_if_no_path && m->queue_size)
-		queue_work(kmultipathd, &m->process_queued_ios);
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return 0;
-}
-
-/*-----------------------------------------------------------------
- * The multipath daemon is responsible for resubmitting queued ios.
- *---------------------------------------------------------------*/
-
-static void dispatch_queued_ios(struct multipath *m)
-{
-	int r;
-	unsigned long flags;
-	union map_info *info;
-	struct request *clone, *n;
-	LIST_HEAD(cl);
-
-	spin_lock_irqsave(&m->lock, flags);
-	list_splice_init(&m->queued_ios, &cl);
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	list_for_each_entry_safe(clone, n, &cl, queuelist) {
-		list_del_init(&clone->queuelist);
-
-		info = dm_get_rq_mapinfo(clone);
-
-		r = map_io(m, clone, info, 1);
-		if (r < 0) {
-			clear_mapinfo(m, info);
-			dm_kill_unmapped_request(clone, r);
-		} else if (r == DM_MAPIO_REMAPPED)
-			dm_dispatch_request(clone);
-		else if (r == DM_MAPIO_REQUEUE) {
-			clear_mapinfo(m, info);
-			dm_requeue_unmapped_request(clone);
-		}
-	}
-}
-
-static void process_queued_ios(struct work_struct *work)
-{
-	struct multipath *m =
-		container_of(work, struct multipath, process_queued_ios);
-	struct pgpath *pgpath = NULL;
-	unsigned must_queue = 1;
-	unsigned long flags;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (!m->queue_size)
-		goto out;
-
-	if (!m->current_pgpath)
-		__choose_pgpath(m, 0);
-
-	pgpath = m->current_pgpath;
-
-	if ((pgpath && !m->queue_io) ||
-	    (!pgpath && !m->queue_if_no_path))
-		must_queue = 0;
-
-	if (m->pg_init_required && !m->pg_init_in_progress && pgpath)
-		__pg_init_all_paths(m);
-
-out:
-	spin_unlock_irqrestore(&m->lock, flags);
-	if (!must_queue)
-		dispatch_queued_ios(m);
-}
-
-/*
- * An event is triggered whenever a path is taken out of use.
- * Includes path failure and PG bypass.
- */
-static void trigger_event(struct work_struct *work)
-{
-	struct multipath *m =
-		container_of(work, struct multipath, trigger_event);
-
-	dm_table_event(m->ti->table);
-}
-
-/*-----------------------------------------------------------------
- * Constructor/argument parsing:
- * <#multipath feature args> [<arg>]*
- * <#hw_handler args> [hw_handler [<arg>]*]
- * <#priority groups>
- * <initial priority group>
- *     [<selector> <#selector args> [<arg>]*
- *      <#paths> <#per-path selector args>
- *         [<path> [<arg>]* ]+ ]+
- *---------------------------------------------------------------*/
-static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
-			       struct dm_target *ti)
-{
-	int r;
-	struct path_selector_type *pst;
-	unsigned ps_argc;
-
-	static struct dm_arg _args[] = {
-		{0, 1024, "invalid number of path selector args"},
-	};
-
-	pst = dm_get_path_selector(dm_shift_arg(as));
-	if (!pst) {
-		ti->error = "unknown path selector type";
-		return -EINVAL;
-	}
-
-	r = dm_read_arg_group(_args, as, &ps_argc, &ti->error);
-	if (r) {
-		dm_put_path_selector(pst);
-		return -EINVAL;
-	}
-
-	r = pst->create(&pg->ps, ps_argc, as->argv);
-	if (r) {
-		dm_put_path_selector(pst);
-		ti->error = "path selector constructor failed";
-		return r;
-	}
-
-	pg->ps.type = pst;
-	dm_consume_args(as, ps_argc);
-
-	return 0;
-}
-
-static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
-			       struct dm_target *ti)
-{
-	int r;
-	struct pgpath *p;
-	struct multipath *m = ti->private;
-
-	/* we need at least a path arg */
-	if (as->argc < 1) {
-		ti->error = "no device given";
-		return ERR_PTR(-EINVAL);
-	}
-
-	p = alloc_pgpath();
-	if (!p)
-		return ERR_PTR(-ENOMEM);
-
-	r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
-			  &p->path.dev);
-	if (r) {
-		ti->error = "error getting device";
-		goto bad;
-	}
-
-	if (m->hw_handler_name) {
-		struct request_queue *q = bdev_get_queue(p->path.dev->bdev);
-
-		r = scsi_dh_attach(q, m->hw_handler_name);
-		if (r == -EBUSY) {
-			/*
-			 * Already attached to different hw_handler,
-			 * try to reattach with correct one.
-			 */
-			scsi_dh_detach(q);
-			r = scsi_dh_attach(q, m->hw_handler_name);
-		}
-
-		if (r < 0) {
-			ti->error = "error attaching hardware handler";
-			dm_put_device(ti, p->path.dev);
-			goto bad;
-		}
-
-		if (m->hw_handler_params) {
-			r = scsi_dh_set_params(q, m->hw_handler_params);
-			if (r < 0) {
-				ti->error = "unable to set hardware "
-							"handler parameters";
-				scsi_dh_detach(q);
-				dm_put_device(ti, p->path.dev);
-				goto bad;
-			}
-		}
-	}
-
-	r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
-	if (r) {
-		dm_put_device(ti, p->path.dev);
-		goto bad;
-	}
-
-	return p;
-
- bad:
-	free_pgpath(p);
-	return ERR_PTR(r);
-}
-
-static struct priority_group *parse_priority_group(struct dm_arg_set *as,
-						   struct multipath *m)
-{
-	static struct dm_arg _args[] = {
-		{1, 1024, "invalid number of paths"},
-		{0, 1024, "invalid number of selector args"}
-	};
-
-	int r;
-	unsigned i, nr_selector_args, nr_args;
-	struct priority_group *pg;
-	struct dm_target *ti = m->ti;
-
-	if (as->argc < 2) {
-		as->argc = 0;
-		ti->error = "not enough priority group arguments";
-		return ERR_PTR(-EINVAL);
-	}
-
-	pg = alloc_priority_group();
-	if (!pg) {
-		ti->error = "couldn't allocate priority group";
-		return ERR_PTR(-ENOMEM);
-	}
-	pg->m = m;
-
-	r = parse_path_selector(as, pg, ti);
-	if (r)
-		goto bad;
-
-	/*
-	 * read the paths
-	 */
-	r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error);
-	if (r)
-		goto bad;
-
-	r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error);
-	if (r)
-		goto bad;
-
-	nr_args = 1 + nr_selector_args;
-	for (i = 0; i < pg->nr_pgpaths; i++) {
-		struct pgpath *pgpath;
-		struct dm_arg_set path_args;
-
-		if (as->argc < nr_args) {
-			ti->error = "not enough path parameters";
-			r = -EINVAL;
-			goto bad;
-		}
-
-		path_args.argc = nr_args;
-		path_args.argv = as->argv;
-
-		pgpath = parse_path(&path_args, &pg->ps, ti);
-		if (IS_ERR(pgpath)) {
-			r = PTR_ERR(pgpath);
-			goto bad;
-		}
-
-		pgpath->pg = pg;
-		list_add_tail(&pgpath->list, &pg->pgpaths);
-		dm_consume_args(as, nr_args);
-	}
-
-	return pg;
-
- bad:
-	free_priority_group(pg, ti);
-	return ERR_PTR(r);
-}
-
-static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
-{
-	unsigned hw_argc;
-	int ret;
-	struct dm_target *ti = m->ti;
-
-	static struct dm_arg _args[] = {
-		{0, 1024, "invalid number of hardware handler args"},
-	};
-
-	if (dm_read_arg_group(_args, as, &hw_argc, &ti->error))
-		return -EINVAL;
-
-	if (!hw_argc)
-		return 0;
-
-	m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
-	if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name),
-				     "scsi_dh_%s", m->hw_handler_name)) {
-		ti->error = "unknown hardware handler type";
-		ret = -EINVAL;
-		goto fail;
-	}
-
-	if (hw_argc > 1) {
-		char *p;
-		int i, j, len = 4;
-
-		for (i = 0; i <= hw_argc - 2; i++)
-			len += strlen(as->argv[i]) + 1;
-		p = m->hw_handler_params = kzalloc(len, GFP_KERNEL);
-		if (!p) {
-			ti->error = "memory allocation failed";
-			ret = -ENOMEM;
-			goto fail;
-		}
-		j = sprintf(p, "%d", hw_argc - 1);
-		for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1)
-			j = sprintf(p, "%s", as->argv[i]);
-	}
-	dm_consume_args(as, hw_argc - 1);
-
-	return 0;
-fail:
-	kfree(m->hw_handler_name);
-	m->hw_handler_name = NULL;
-	return ret;
-}
-
-static int parse_features(struct dm_arg_set *as, struct multipath *m)
-{
-	int r;
-	unsigned argc;
-	struct dm_target *ti = m->ti;
-	const char *arg_name;
-
-	static struct dm_arg _args[] = {
-		{0, 5, "invalid number of feature args"},
-		{1, 50, "pg_init_retries must be between 1 and 50"},
-		{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
-	};
-
-	r = dm_read_arg_group(_args, as, &argc, &ti->error);
-	if (r)
-		return -EINVAL;
-
-	if (!argc)
-		return 0;
-
-	do {
-		arg_name = dm_shift_arg(as);
-		argc--;
-
-		if (!strcasecmp(arg_name, "queue_if_no_path")) {
-			r = queue_if_no_path(m, 1, 0);
-			continue;
-		}
-
-		if (!strcasecmp(arg_name, "pg_init_retries") &&
-		    (argc >= 1)) {
-			r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
-			argc--;
-			continue;
-		}
-
-		if (!strcasecmp(arg_name, "pg_init_delay_msecs") &&
-		    (argc >= 1)) {
-			r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error);
-			argc--;
-			continue;
-		}
-
-		ti->error = "Unrecognised multipath feature request";
-		r = -EINVAL;
-	} while (argc && !r);
-
-	return r;
-}
-
-static int multipath_ctr(struct dm_target *ti, unsigned int argc,
-			 char **argv)
-{
-	/* target arguments */
-	static struct dm_arg _args[] = {
-		{0, 1024, "invalid number of priority groups"},
-		{0, 1024, "invalid initial priority group number"},
-	};
-
-	int r;
-	struct multipath *m;
-	struct dm_arg_set as;
-	unsigned pg_count = 0;
-	unsigned next_pg_num;
-
-	as.argc = argc;
-	as.argv = argv;
-
-	m = alloc_multipath(ti);
-	if (!m) {
-		ti->error = "can't allocate multipath";
-		return -EINVAL;
-	}
-
-	r = parse_features(&as, m);
-	if (r)
-		goto bad;
-
-	r = parse_hw_handler(&as, m);
-	if (r)
-		goto bad;
-
-	r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error);
-	if (r)
-		goto bad;
-
-	r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error);
-	if (r)
-		goto bad;
-
-	if ((!m->nr_priority_groups && next_pg_num) ||
-	    (m->nr_priority_groups && !next_pg_num)) {
-		ti->error = "invalid initial priority group";
-		r = -EINVAL;
-		goto bad;
-	}
-
-	/* parse the priority groups */
-	while (as.argc) {
-		struct priority_group *pg;
-
-		pg = parse_priority_group(&as, m);
-		if (IS_ERR(pg)) {
-			r = PTR_ERR(pg);
-			goto bad;
-		}
-
-		m->nr_valid_paths += pg->nr_pgpaths;
-		list_add_tail(&pg->list, &m->priority_groups);
-		pg_count++;
-		pg->pg_num = pg_count;
-		if (!--next_pg_num)
-			m->next_pg = pg;
-	}
-
-	if (pg_count != m->nr_priority_groups) {
-		ti->error = "priority group count mismatch";
-		r = -EINVAL;
-		goto bad;
-	}
-
-	ti->num_flush_requests = 1;
-	ti->num_discard_requests = 1;
-
-	return 0;
-
- bad:
-	free_multipath(m);
-	return r;
-}
-
-static void multipath_wait_for_pg_init_completion(struct multipath *m)
-{
-	DECLARE_WAITQUEUE(wait, current);
-	unsigned long flags;
-
-	add_wait_queue(&m->pg_init_wait, &wait);
-
-	while (1) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-
-		spin_lock_irqsave(&m->lock, flags);
-		if (!m->pg_init_in_progress) {
-			spin_unlock_irqrestore(&m->lock, flags);
-			break;
-		}
-		spin_unlock_irqrestore(&m->lock, flags);
-
-		io_schedule();
-	}
-	set_current_state(TASK_RUNNING);
-
-	remove_wait_queue(&m->pg_init_wait, &wait);
-}
-
-static void flush_multipath_work(struct multipath *m)
-{
-	flush_workqueue(kmpath_handlerd);
-	multipath_wait_for_pg_init_completion(m);
-	flush_workqueue(kmultipathd);
-	flush_work_sync(&m->trigger_event);
-}
-
-static void multipath_dtr(struct dm_target *ti)
-{
-	struct multipath *m = ti->private;
-
-	flush_multipath_work(m);
-	free_multipath(m);
-}
-
-/*
- * Map cloned requests
- */
-static int multipath_map(struct dm_target *ti, struct request *clone,
-			 union map_info *map_context)
-{
-	int r;
-	struct multipath *m = (struct multipath *) ti->private;
-
-	if (set_mapinfo(m, map_context) < 0)
-		/* ENOMEM, requeue */
-		return DM_MAPIO_REQUEUE;
-
-	clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
-	r = map_io(m, clone, map_context, 0);
-	if (r < 0 || r == DM_MAPIO_REQUEUE)
-		clear_mapinfo(m, map_context);
-
-	return r;
-}
-
-/*
- * Take a path out of use.
- */
-static int fail_path(struct pgpath *pgpath)
-{
-	unsigned long flags;
-	struct multipath *m = pgpath->pg->m;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (!pgpath->is_active)
-		goto out;
-
-	DMWARN("Failing path %s.", pgpath->path.dev->name);
-
-	pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
-	pgpath->is_active = 0;
-	pgpath->fail_count++;
-
-	m->nr_valid_paths--;
-
-	if (pgpath == m->current_pgpath)
-		m->current_pgpath = NULL;
-
-	dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
-		      pgpath->path.dev->name, m->nr_valid_paths);
-
-	schedule_work(&m->trigger_event);
-
-out:
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return 0;
-}
-
-/*
- * Reinstate a previously-failed path
- */
-static int reinstate_path(struct pgpath *pgpath)
-{
-	int r = 0;
-	unsigned long flags;
-	struct multipath *m = pgpath->pg->m;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (pgpath->is_active)
-		goto out;
-
-	if (!pgpath->pg->ps.type->reinstate_path) {
-		DMWARN("Reinstate path not supported by path selector %s",
-		       pgpath->pg->ps.type->name);
-		r = -EINVAL;
-		goto out;
-	}
-
-	r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
-	if (r)
-		goto out;
-
-	pgpath->is_active = 1;
-
-	if (!m->nr_valid_paths++ && m->queue_size) {
-		m->current_pgpath = NULL;
-		queue_work(kmultipathd, &m->process_queued_ios);
-	} else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
-		if (queue_work(kmpath_handlerd, &pgpath->activate_path.work))
-			m->pg_init_in_progress++;
-	}
-
-	dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
-		      pgpath->path.dev->name, m->nr_valid_paths);
-
-	schedule_work(&m->trigger_event);
-
-out:
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return r;
-}
-
-/*
- * Fail or reinstate all paths that match the provided struct dm_dev.
- */
-static int action_dev(struct multipath *m, struct dm_dev *dev,
-		      action_fn action)
-{
-	int r = -EINVAL;
-	struct pgpath *pgpath;
-	struct priority_group *pg;
-
-	list_for_each_entry(pg, &m->priority_groups, list) {
-		list_for_each_entry(pgpath, &pg->pgpaths, list) {
-			if (pgpath->path.dev == dev)
-				r = action(pgpath);
-		}
-	}
-
-	return r;
-}
-
-/*
- * Temporarily try to avoid having to use the specified PG
- */
-static void bypass_pg(struct multipath *m, struct priority_group *pg,
-		      int bypassed)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	pg->bypassed = bypassed;
-	m->current_pgpath = NULL;
-	m->current_pg = NULL;
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	schedule_work(&m->trigger_event);
-}
-
-/*
- * Switch to using the specified PG from the next I/O that gets mapped
- */
-static int switch_pg_num(struct multipath *m, const char *pgstr)
-{
-	struct priority_group *pg;
-	unsigned pgnum;
-	unsigned long flags;
-	char dummy;
-
-	if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
-	    (pgnum > m->nr_priority_groups)) {
-		DMWARN("invalid PG number supplied to switch_pg_num");
-		return -EINVAL;
-	}
-
-	spin_lock_irqsave(&m->lock, flags);
-	list_for_each_entry(pg, &m->priority_groups, list) {
-		pg->bypassed = 0;
-		if (--pgnum)
-			continue;
-
-		m->current_pgpath = NULL;
-		m->current_pg = NULL;
-		m->next_pg = pg;
-	}
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	schedule_work(&m->trigger_event);
-	return 0;
-}
-
-/*
- * Set/clear bypassed status of a PG.
- * PGs are numbered upwards from 1 in the order they were declared.
- */
-static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
-{
-	struct priority_group *pg;
-	unsigned pgnum;
-	char dummy;
-
-	if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
-	    (pgnum > m->nr_priority_groups)) {
-		DMWARN("invalid PG number supplied to bypass_pg");
-		return -EINVAL;
-	}
-
-	list_for_each_entry(pg, &m->priority_groups, list) {
-		if (!--pgnum)
-			break;
-	}
-
-	bypass_pg(m, pg, bypassed);
-	return 0;
-}
-
-/*
- * Should we retry pg_init immediately?
- */
-static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
-{
-	unsigned long flags;
-	int limit_reached = 0;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (m->pg_init_count <= m->pg_init_retries)
-		m->pg_init_required = 1;
-	else
-		limit_reached = 1;
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return limit_reached;
-}
-
-static void pg_init_done(void *data, int errors)
-{
-	struct pgpath *pgpath = data;
-	struct priority_group *pg = pgpath->pg;
-	struct multipath *m = pg->m;
-	unsigned long flags;
-	unsigned delay_retry = 0;
-
-	/* device or driver problems */
-	switch (errors) {
-	case SCSI_DH_OK:
-		break;
-	case SCSI_DH_NOSYS:
-		if (!m->hw_handler_name) {
-			errors = 0;
-			break;
-		}
-		DMERR("Could not failover the device: Handler scsi_dh_%s "
-		      "Error %d.", m->hw_handler_name, errors);
-		/*
-		 * Fail path for now, so we do not ping pong
-		 */
-		fail_path(pgpath);
-		break;
-	case SCSI_DH_DEV_TEMP_BUSY:
-		/*
-		 * Probably doing something like FW upgrade on the
-		 * controller so try the other pg.
-		 */
-		bypass_pg(m, pg, 1);
-		break;
-	case SCSI_DH_RETRY:
-		/* Wait before retrying. */
-		delay_retry = 1;
-	case SCSI_DH_IMM_RETRY:
-	case SCSI_DH_RES_TEMP_UNAVAIL:
-		if (pg_init_limit_reached(m, pgpath))
-			fail_path(pgpath);
-		errors = 0;
-		break;
-	default:
-		/*
-		 * We probably do not want to fail the path for a device
-		 * error, but this is what the old dm did. In future
-		 * patches we can do more advanced handling.
-		 */
-		fail_path(pgpath);
-	}
-
-	spin_lock_irqsave(&m->lock, flags);
-	if (errors) {
-		if (pgpath == m->current_pgpath) {
-			DMERR("Could not failover device. Error %d.", errors);
-			m->current_pgpath = NULL;
-			m->current_pg = NULL;
-		}
-	} else if (!m->pg_init_required)
-		pg->bypassed = 0;
-
-	if (--m->pg_init_in_progress)
-		/* Activations of other paths are still on going */
-		goto out;
-
-	if (!m->pg_init_required)
-		m->queue_io = 0;
-
-	m->pg_init_delay_retry = delay_retry;
-	queue_work(kmultipathd, &m->process_queued_ios);
-
-	/*
-	 * Wake up any thread waiting to suspend.
-	 */
-	wake_up(&m->pg_init_wait);
-
-out:
-	spin_unlock_irqrestore(&m->lock, flags);
-}
-
-static void activate_path(struct work_struct *work)
-{
-	struct pgpath *pgpath =
-		container_of(work, struct pgpath, activate_path.work);
-
-	scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
-				pg_init_done, pgpath);
-}
-
-/*
- * end_io handling
- */
-static int do_end_io(struct multipath *m, struct request *clone,
-		     int error, struct dm_mpath_io *mpio)
-{
-	/*
-	 * We don't queue any clone request inside the multipath target
-	 * during end I/O handling, since those clone requests don't have
-	 * bio clones.  If we queue them inside the multipath target,
-	 * we need to make bio clones, that requires memory allocation.
-	 * (See drivers/md/dm.c:end_clone_bio() about why the clone requests
-	 *  don't have bio clones.)
-	 * Instead of queueing the clone request here, we queue the original
-	 * request into dm core, which will remake a clone request and
-	 * clone bios for it and resubmit it later.
-	 */
-	int r = DM_ENDIO_REQUEUE;
-	unsigned long flags;
-
-	if (!error && !clone->errors)
-		return 0;	/* I/O complete */
-
-	if (error == -EOPNOTSUPP || error == -EREMOTEIO || error == -EILSEQ)
-		return error;
-
-	if (mpio->pgpath)
-		fail_path(mpio->pgpath);
-
-	spin_lock_irqsave(&m->lock, flags);
-	if (!m->nr_valid_paths) {
-		if (!m->queue_if_no_path) {
-			if (!__must_push_back(m))
-				r = -EIO;
-		} else {
-			if (error == -EBADE)
-				r = error;
-		}
-	}
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return r;
-}
-
-static int multipath_end_io(struct dm_target *ti, struct request *clone,
-			    int error, union map_info *map_context)
-{
-	struct multipath *m = ti->private;
-	struct dm_mpath_io *mpio = map_context->ptr;
-	struct pgpath *pgpath = mpio->pgpath;
-	struct path_selector *ps;
-	int r;
-
-	BUG_ON(!mpio);
-
-	r  = do_end_io(m, clone, error, mpio);
-	if (pgpath) {
-		ps = &pgpath->pg->ps;
-		if (ps->type->end_io)
-			ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
-	}
-	clear_mapinfo(m, map_context);
-
-	return r;
-}
-
-/*
- * Suspend can't complete until all the I/O is processed so if
- * the last path fails we must error any remaining I/O.
- * Note that if the freeze_bdev fails while suspending, the
- * queue_if_no_path state is lost - userspace should reset it.
- */
-static void multipath_presuspend(struct dm_target *ti)
-{
-	struct multipath *m = (struct multipath *) ti->private;
-
-	queue_if_no_path(m, 0, 1);
-}
-
-static void multipath_postsuspend(struct dm_target *ti)
-{
-	struct multipath *m = ti->private;
-
-	mutex_lock(&m->work_mutex);
-	flush_multipath_work(m);
-	mutex_unlock(&m->work_mutex);
-}
-
-/*
- * Restore the queue_if_no_path setting.
- */
-static void multipath_resume(struct dm_target *ti)
-{
-	struct multipath *m = (struct multipath *) ti->private;
-	unsigned long flags;
-
-	spin_lock_irqsave(&m->lock, flags);
-	m->queue_if_no_path = m->saved_queue_if_no_path;
-	spin_unlock_irqrestore(&m->lock, flags);
-}
-
-/*
- * Info output has the following format:
- * num_multipath_feature_args [multipath_feature_args]*
- * num_handler_status_args [handler_status_args]*
- * num_groups init_group_number
- *            [A|D|E num_ps_status_args [ps_status_args]*
- *             num_paths num_selector_args
- *             [path_dev A|F fail_count [selector_args]* ]+ ]+
- *
- * Table output has the following format (identical to the constructor string):
- * num_feature_args [features_args]*
- * num_handler_args hw_handler [hw_handler_args]*
- * num_groups init_group_number
- *     [priority selector-name num_ps_args [ps_args]*
- *      num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
- */
-static int multipath_status(struct dm_target *ti, status_type_t type,
-			    char *result, unsigned int maxlen)
-{
-	int sz = 0;
-	unsigned long flags;
-	struct multipath *m = (struct multipath *) ti->private;
-	struct priority_group *pg;
-	struct pgpath *p;
-	unsigned pg_num;
-	char state;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	/* Features */
-	if (type == STATUSTYPE_INFO)
-		DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count);
-	else {
-		DMEMIT("%u ", m->queue_if_no_path +
-			      (m->pg_init_retries > 0) * 2 +
-			      (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2);
-		if (m->queue_if_no_path)
-			DMEMIT("queue_if_no_path ");
-		if (m->pg_init_retries)
-			DMEMIT("pg_init_retries %u ", m->pg_init_retries);
-		if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
-			DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
-	}
-
-	if (!m->hw_handler_name || type == STATUSTYPE_INFO)
-		DMEMIT("0 ");
-	else
-		DMEMIT("1 %s ", m->hw_handler_name);
-
-	DMEMIT("%u ", m->nr_priority_groups);
-
-	if (m->next_pg)
-		pg_num = m->next_pg->pg_num;
-	else if (m->current_pg)
-		pg_num = m->current_pg->pg_num;
-	else
-		pg_num = (m->nr_priority_groups ? 1 : 0);
-
-	DMEMIT("%u ", pg_num);
-
-	switch (type) {
-	case STATUSTYPE_INFO:
-		list_for_each_entry(pg, &m->priority_groups, list) {
-			if (pg->bypassed)
-				state = 'D';	/* Disabled */
-			else if (pg == m->current_pg)
-				state = 'A';	/* Currently Active */
-			else
-				state = 'E';	/* Enabled */
-
-			DMEMIT("%c ", state);
-
-			if (pg->ps.type->status)
-				sz += pg->ps.type->status(&pg->ps, NULL, type,
-							  result + sz,
-							  maxlen - sz);
-			else
-				DMEMIT("0 ");
-
-			DMEMIT("%u %u ", pg->nr_pgpaths,
-			       pg->ps.type->info_args);
-
-			list_for_each_entry(p, &pg->pgpaths, list) {
-				DMEMIT("%s %s %u ", p->path.dev->name,
-				       p->is_active ? "A" : "F",
-				       p->fail_count);
-				if (pg->ps.type->status)
-					sz += pg->ps.type->status(&pg->ps,
-					      &p->path, type, result + sz,
-					      maxlen - sz);
-			}
-		}
-		break;
-
-	case STATUSTYPE_TABLE:
-		list_for_each_entry(pg, &m->priority_groups, list) {
-			DMEMIT("%s ", pg->ps.type->name);
-
-			if (pg->ps.type->status)
-				sz += pg->ps.type->status(&pg->ps, NULL, type,
-							  result + sz,
-							  maxlen - sz);
-			else
-				DMEMIT("0 ");
-
-			DMEMIT("%u %u ", pg->nr_pgpaths,
-			       pg->ps.type->table_args);
-
-			list_for_each_entry(p, &pg->pgpaths, list) {
-				DMEMIT("%s ", p->path.dev->name);
-				if (pg->ps.type->status)
-					sz += pg->ps.type->status(&pg->ps,
-					      &p->path, type, result + sz,
-					      maxlen - sz);
-			}
-		}
-		break;
-	}
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return 0;
-}
-
-static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
-{
-	int r = -EINVAL;
-	struct dm_dev *dev;
-	struct multipath *m = (struct multipath *) ti->private;
-	action_fn action;
-
-	mutex_lock(&m->work_mutex);
-
-	if (dm_suspended(ti)) {
-		r = -EBUSY;
-		goto out;
-	}
-
-	if (argc == 1) {
-		if (!strcasecmp(argv[0], "queue_if_no_path")) {
-			r = queue_if_no_path(m, 1, 0);
-			goto out;
-		} else if (!strcasecmp(argv[0], "fail_if_no_path")) {
-			r = queue_if_no_path(m, 0, 0);
-			goto out;
-		}
-	}
-
-	if (argc != 2) {
-		DMWARN("Unrecognised multipath message received.");
-		goto out;
-	}
-
-	if (!strcasecmp(argv[0], "disable_group")) {
-		r = bypass_pg_num(m, argv[1], 1);
-		goto out;
-	} else if (!strcasecmp(argv[0], "enable_group")) {
-		r = bypass_pg_num(m, argv[1], 0);
-		goto out;
-	} else if (!strcasecmp(argv[0], "switch_group")) {
-		r = switch_pg_num(m, argv[1]);
-		goto out;
-	} else if (!strcasecmp(argv[0], "reinstate_path"))
-		action = reinstate_path;
-	else if (!strcasecmp(argv[0], "fail_path"))
-		action = fail_path;
-	else {
-		DMWARN("Unrecognised multipath message received.");
-		goto out;
-	}
-
-	r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev);
-	if (r) {
-		DMWARN("message: error getting device %s",
-		       argv[1]);
-		goto out;
-	}
-
-	r = action_dev(m, dev, action);
-
-	dm_put_device(ti, dev);
-
-out:
-	mutex_unlock(&m->work_mutex);
-	return r;
-}
-
-static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
-			   unsigned long arg)
-{
-	struct multipath *m = (struct multipath *) ti->private;
-	struct block_device *bdev = NULL;
-	fmode_t mode = 0;
-	unsigned long flags;
-	int r = 0;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	if (!m->current_pgpath)
-		__choose_pgpath(m, 0);
-
-	if (m->current_pgpath) {
-		bdev = m->current_pgpath->path.dev->bdev;
-		mode = m->current_pgpath->path.dev->mode;
-	}
-
-	if (m->queue_io)
-		r = -EAGAIN;
-	else if (!bdev)
-		r = -EIO;
-
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	/*
-	 * Only pass ioctls through if the device sizes match exactly.
-	 */
-	if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT)
-		r = scsi_verify_blk_ioctl(NULL, cmd);
-
-	return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
-}
-
-static int multipath_iterate_devices(struct dm_target *ti,
-				     iterate_devices_callout_fn fn, void *data)
-{
-	struct multipath *m = ti->private;
-	struct priority_group *pg;
-	struct pgpath *p;
-	int ret = 0;
-
-	list_for_each_entry(pg, &m->priority_groups, list) {
-		list_for_each_entry(p, &pg->pgpaths, list) {
-			ret = fn(ti, p->path.dev, ti->begin, ti->len, data);
-			if (ret)
-				goto out;
-		}
-	}
-
-out:
-	return ret;
-}
-
-static int __pgpath_busy(struct pgpath *pgpath)
-{
-	struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
-
-	return dm_underlying_device_busy(q);
-}
-
-/*
- * We return "busy", only when we can map I/Os but underlying devices
- * are busy (so even if we map I/Os now, the I/Os will wait on
- * the underlying queue).
- * In other words, if we want to kill I/Os or queue them inside us
- * due to map unavailability, we don't return "busy".  Otherwise,
- * dm core won't give us the I/Os and we can't do what we want.
- */
-static int multipath_busy(struct dm_target *ti)
-{
-	int busy = 0, has_active = 0;
-	struct multipath *m = ti->private;
-	struct priority_group *pg;
-	struct pgpath *pgpath;
-	unsigned long flags;
-
-	spin_lock_irqsave(&m->lock, flags);
-
-	/* Guess which priority_group will be used at next mapping time */
-	if (unlikely(!m->current_pgpath && m->next_pg))
-		pg = m->next_pg;
-	else if (likely(m->current_pg))
-		pg = m->current_pg;
-	else
-		/*
-		 * We don't know which pg will be used at next mapping time.
-		 * We don't call __choose_pgpath() here to avoid to trigger
-		 * pg_init just by busy checking.
-		 * So we don't know whether underlying devices we will be using
-		 * at next mapping time are busy or not. Just try mapping.
-		 */
-		goto out;
-
-	/*
-	 * If there is one non-busy active path at least, the path selector
-	 * will be able to select it. So we consider such a pg as not busy.
-	 */
-	busy = 1;
-	list_for_each_entry(pgpath, &pg->pgpaths, list)
-		if (pgpath->is_active) {
-			has_active = 1;
-
-			if (!__pgpath_busy(pgpath)) {
-				busy = 0;
-				break;
-			}
-		}
-
-	if (!has_active)
-		/*
-		 * No active path in this pg, so this pg won't be used and
-		 * the current_pg will be changed at next mapping time.
-		 * We need to try mapping to determine it.
-		 */
-		busy = 0;
-
-out:
-	spin_unlock_irqrestore(&m->lock, flags);
-
-	return busy;
-}
-
-/*-----------------------------------------------------------------
- * Module setup
- *---------------------------------------------------------------*/
-static struct target_type multipath_target = {
-	.name = "multipath",
-	.version = {1, 3, 0},
-	.module = THIS_MODULE,
-	.ctr = multipath_ctr,
-	.dtr = multipath_dtr,
-	.map_rq = multipath_map,
-	.rq_end_io = multipath_end_io,
-	.presuspend = multipath_presuspend,
-	.postsuspend = multipath_postsuspend,
-	.resume = multipath_resume,
-	.status = multipath_status,
-	.message = multipath_message,
-	.ioctl  = multipath_ioctl,
-	.iterate_devices = multipath_iterate_devices,
-	.busy = multipath_busy,
-};
-
-static int __init dm_multipath_init(void)
-{
-	int r;
-
-	/* allocate a slab for the dm_ios */
-	_mpio_cache = KMEM_CACHE(dm_mpath_io, 0);
-	if (!_mpio_cache)
-		return -ENOMEM;
-
-	r = dm_register_target(&multipath_target);
-	if (r < 0) {
-		DMERR("register failed %d", r);
-		kmem_cache_destroy(_mpio_cache);
-		return -EINVAL;
-	}
-
-	kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
-	if (!kmultipathd) {
-		DMERR("failed to create workqueue kmpathd");
-		dm_unregister_target(&multipath_target);
-		kmem_cache_destroy(_mpio_cache);
-		return -ENOMEM;
-	}
-
-	/*
-	 * A separate workqueue is used to handle the device handlers
-	 * to avoid overloading existing workqueue. Overloading the
-	 * old workqueue would also create a bottleneck in the
-	 * path of the storage hardware device activation.
-	 */
-	kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd",
-						  WQ_MEM_RECLAIM);
-	if (!kmpath_handlerd) {
-		DMERR("failed to create workqueue kmpath_handlerd");
-		destroy_workqueue(kmultipathd);
-		dm_unregister_target(&multipath_target);
-		kmem_cache_destroy(_mpio_cache);
-		return -ENOMEM;
-	}
-
-	DMINFO("version %u.%u.%u loaded",
-	       multipath_target.version[0], multipath_target.version[1],
-	       multipath_target.version[2]);
-
-	return r;
-}
-
-static void __exit dm_multipath_exit(void)
-{
-	destroy_workqueue(kmpath_handlerd);
-	destroy_workqueue(kmultipathd);
-
-	dm_unregister_target(&multipath_target);
-	kmem_cache_destroy(_mpio_cache);
-}
-
-module_init(dm_multipath_init);
-module_exit(dm_multipath_exit);
-
-MODULE_DESCRIPTION(DM_NAME " multipath target");
-MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
-MODULE_LICENSE("GPL");