X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fmd%2Fdm-mpath.c;h=3d7f4923cd133a2216115bb18d6fb177eb93ffd1;hb=6b41e7dd90c6a628ab5fb8d781302d60a243b2ce;hp=de54b39e6ffe9fb78cbad18c2a5d5b559d54d870;hpb=79eb885c96b5ccf8bbffd0dddc4c15a5dd436a1c;p=safe%2Fjmp%2Flinux-2.6

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index de54b39..3d7f492 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -5,11 +5,12 @@
  * This file is released under the GPL.
  */
 
-#include "dm.h"
+#include <linux/device-mapper.h>
+
 #include "dm-path-selector.h"
-#include "dm-hw-handler.h"
 #include "dm-bio-list.h"
 #include "dm-bio-record.h"
+#include "dm-uevent.h"
 
 #include <linux/ctype.h>
 #include <linux/init.h>
@@ -19,6 +20,7 @@
 #include <linux/slab.h>
 #include <linux/time.h>
 #include <linux/workqueue.h>
+#include <scsi/scsi_dh.h>
 #include <asm/atomic.h>
 
 #define DM_MSG_PREFIX "multipath"
@@ -29,9 +31,11 @@ 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 work_struct deactivate_path;
 };
 
 #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
@@ -60,7 +64,9 @@ struct multipath {
 
 	spinlock_t lock;
 
-	struct hw_handler hw_handler;
+	const char *hw_handler_name;
+	struct work_struct activate_path;
+	struct pgpath *pgpath_to_activate;
 	unsigned nr_priority_groups;
 	struct list_head priority_groups;
 	unsigned pg_init_required;	/* pg_init needs calling? */
@@ -75,6 +81,8 @@ struct multipath {
 	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 */
 
 	struct work_struct process_queued_ios;
 	struct bio_list queued_ios;
@@ -83,7 +91,7 @@ struct multipath {
 	struct work_struct trigger_event;
 
 	/*
-	 * We must use a mempool of mpath_io structs so that we
+	 * We must use a mempool of dm_mpath_io structs so that we
 	 * can resubmit bios on error.
 	 */
 	mempool_t *mpio_pool;
@@ -92,7 +100,7 @@ struct multipath {
 /*
  * Context information attached to each bio we process.
  */
-struct mpath_io {
+struct dm_mpath_io {
 	struct pgpath *pgpath;
 	struct dm_bio_details details;
 };
@@ -103,9 +111,11 @@ typedef int (*action_fn) (struct pgpath *pgpath);
 
 static struct kmem_cache *_mpio_cache;
 
-struct workqueue_struct *kmultipathd;
+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);
+static void deactivate_path(struct work_struct *work);
 
 
 /*-----------------------------------------------
@@ -116,17 +126,27 @@ static struct pgpath *alloc_pgpath(void)
 {
 	struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
 
-	if (pgpath)
-		pgpath->path.is_active = 1;
+	if (pgpath) {
+		pgpath->is_active = 1;
+		INIT_WORK(&pgpath->deactivate_path, deactivate_path);
+	}
 
 	return pgpath;
 }
 
-static inline void free_pgpath(struct pgpath *pgpath)
+static void free_pgpath(struct pgpath *pgpath)
 {
 	kfree(pgpath);
 }
 
+static void deactivate_path(struct work_struct *work)
+{
+	struct pgpath *pgpath =
+		container_of(work, struct pgpath, deactivate_path);
+
+	blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue);
+}
+
 static struct priority_group *alloc_priority_group(void)
 {
 	struct priority_group *pg;
@@ -141,11 +161,19 @@ static struct priority_group *alloc_priority_group(void)
 
 static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
 {
+	unsigned long flags;
 	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);
+		spin_lock_irqsave(&m->lock, flags);
+		if (m->pgpath_to_activate == pgpath)
+			m->pgpath_to_activate = NULL;
+		spin_unlock_irqrestore(&m->lock, flags);
 		free_pgpath(pgpath);
 	}
 }
@@ -175,6 +203,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
 		m->queue_io = 1;
 		INIT_WORK(&m->process_queued_ios, process_queued_ios);
 		INIT_WORK(&m->trigger_event, trigger_event);
+		INIT_WORK(&m->activate_path, activate_path);
 		m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
 		if (!m->mpio_pool) {
 			kfree(m);
@@ -190,18 +219,13 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
 static void free_multipath(struct multipath *m)
 {
 	struct priority_group *pg, *tmp;
-	struct hw_handler *hwh = &m->hw_handler;
 
 	list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
 		list_del(&pg->list);
 		free_priority_group(pg, m->ti);
 	}
 
-	if (hwh->type) {
-		hwh->type->destroy(hwh);
-		dm_put_hw_handler(hwh->type);
-	}
-
+	kfree(m->hw_handler_name);
 	mempool_destroy(m->mpio_pool);
 	kfree(m);
 }
@@ -213,18 +237,18 @@ static void free_multipath(struct multipath *m)
 
 static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
 {
-	struct hw_handler *hwh = &m->hw_handler;
-
 	m->current_pg = pgpath->pg;
 
 	/* Must we initialise the PG first, and queue I/O till it's ready? */
-	if (hwh->type && hwh->type->pg_init) {
+	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)
@@ -299,8 +323,8 @@ static int __must_push_back(struct multipath *m)
 		dm_noflush_suspending(m->ti));
 }
 
-static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
-		  unsigned was_queued)
+static int map_io(struct multipath *m, struct bio *bio,
+		  struct dm_mpath_io *mpio, unsigned was_queued)
 {
 	int r = DM_MAPIO_REMAPPED;
 	unsigned long flags;
@@ -374,7 +398,7 @@ static void dispatch_queued_ios(struct multipath *m)
 	int r;
 	unsigned long flags;
 	struct bio *bio = NULL, *next;
-	struct mpath_io *mpio;
+	struct dm_mpath_io *mpio;
 	union map_info *info;
 
 	spin_lock_irqsave(&m->lock, flags);
@@ -390,11 +414,11 @@ static void dispatch_queued_ios(struct multipath *m)
 
 		r = map_io(m, bio, mpio, 1);
 		if (r < 0)
-			bio_endio(bio, bio->bi_size, r);
+			bio_endio(bio, r);
 		else if (r == DM_MAPIO_REMAPPED)
 			generic_make_request(bio);
 		else if (r == DM_MAPIO_REQUEUE)
-			bio_endio(bio, bio->bi_size, -EIO);
+			bio_endio(bio, -EIO);
 
 		bio = next;
 	}
@@ -404,7 +428,6 @@ static void process_queued_ios(struct work_struct *work)
 {
 	struct multipath *m =
 		container_of(work, struct multipath, process_queued_ios);
-	struct hw_handler *hwh = &m->hw_handler;
 	struct pgpath *pgpath = NULL;
 	unsigned init_required = 0, must_queue = 1;
 	unsigned long flags;
@@ -423,7 +446,9 @@ static void process_queued_ios(struct work_struct *work)
 	    (!pgpath && !m->queue_if_no_path))
 		must_queue = 0;
 
-	if (m->pg_init_required && !m->pg_init_in_progress) {
+	if (m->pg_init_required && !m->pg_init_in_progress && pgpath) {
+		m->pgpath_to_activate = pgpath;
+		m->pg_init_count++;
 		m->pg_init_required = 0;
 		m->pg_init_in_progress = 1;
 		init_required = 1;
@@ -433,7 +458,7 @@ out:
 	spin_unlock_irqrestore(&m->lock, flags);
 
 	if (init_required)
-		hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path);
+		queue_work(kmpath_handlerd, &m->activate_path);
 
 	if (!must_queue)
 		dispatch_queued_ios(m);
@@ -524,8 +549,10 @@ static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
 	}
 
 	r = read_param(_params, shift(as), &ps_argc, &ti->error);
-	if (r)
+	if (r) {
+		dm_put_path_selector(pst);
 		return -EINVAL;
+	}
 
 	r = pst->create(&pg->ps, ps_argc, as->argv);
 	if (r) {
@@ -545,16 +572,17 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 {
 	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 NULL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	p = alloc_pgpath();
 	if (!p)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	r = dm_get_device(ti, shift(as), ti->begin, ti->len,
 			  dm_table_get_mode(ti->table), &p->path.dev);
@@ -563,6 +591,15 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 		goto bad;
 	}
 
+	if (m->hw_handler_name) {
+		r = scsi_dh_attach(bdev_get_queue(p->path.dev->bdev),
+				   m->hw_handler_name);
+		if (r < 0) {
+			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);
@@ -573,7 +610,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 
  bad:
 	free_pgpath(p);
-	return NULL;
+	return ERR_PTR(r);
 }
 
 static struct priority_group *parse_priority_group(struct arg_set *as,
@@ -591,14 +628,14 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 
 	if (as->argc < 2) {
 		as->argc = 0;
-		ti->error = "not enough priority group aruments";
-		return NULL;
+		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 NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 	pg->m = m;
 
@@ -622,15 +659,19 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 		struct pgpath *pgpath;
 		struct arg_set path_args;
 
-		if (as->argc < nr_params)
+		if (as->argc < nr_params) {
+			ti->error = "not enough path parameters";
 			goto bad;
+		}
 
 		path_args.argc = nr_params;
 		path_args.argv = as->argv;
 
 		pgpath = parse_path(&path_args, &pg->ps, ti);
-		if (!pgpath)
+		if (IS_ERR(pgpath)) {
+			r = PTR_ERR(pgpath);
 			goto bad;
+		}
 
 		pgpath->pg = pg;
 		list_add_tail(&pgpath->list, &pg->pgpaths);
@@ -641,13 +682,11 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 
  bad:
 	free_priority_group(pg, ti);
-	return NULL;
+	return ERR_PTR(r);
 }
 
 static int parse_hw_handler(struct arg_set *as, struct multipath *m)
 {
-	int r;
-	struct hw_handler_type *hwht;
 	unsigned hw_argc;
 	struct dm_target *ti = m->ti;
 
@@ -655,30 +694,24 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
 		{0, 1024, "invalid number of hardware handler args"},
 	};
 
-	r = read_param(_params, shift(as), &hw_argc, &ti->error);
-	if (r)
+	if (read_param(_params, shift(as), &hw_argc, &ti->error))
 		return -EINVAL;
 
 	if (!hw_argc)
 		return 0;
 
-	hwht = dm_get_hw_handler(shift(as));
-	if (!hwht) {
+	m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
+	request_module("scsi_dh_%s", m->hw_handler_name);
+	if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
 		ti->error = "unknown hardware handler type";
+		kfree(m->hw_handler_name);
+		m->hw_handler_name = NULL;
 		return -EINVAL;
 	}
 
-	m->hw_handler.md = dm_table_get_md(ti->table);
-	dm_put(m->hw_handler.md);
-
-	r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
-	if (r) {
-		dm_put_hw_handler(hwht);
-		ti->error = "hardware handler constructor failed";
-		return r;
-	}
-
-	m->hw_handler.type = hwht;
+	if (hw_argc > 1)
+		DMWARN("Ignoring user-specified arguments for "
+		       "hardware handler \"%s\"", m->hw_handler_name);
 	consume(as, hw_argc - 1);
 
 	return 0;
@@ -689,9 +722,11 @@ static int parse_features(struct arg_set *as, struct multipath *m)
 	int r;
 	unsigned argc;
 	struct dm_target *ti = m->ti;
+	const char *param_name;
 
 	static struct param _params[] = {
-		{0, 1, "invalid number of feature args"},
+		{0, 3, "invalid number of feature args"},
+		{1, 50, "pg_init_retries must be between 1 and 50"},
 	};
 
 	r = read_param(_params, shift(as), &argc, &ti->error);
@@ -701,12 +736,28 @@ static int parse_features(struct arg_set *as, struct multipath *m)
 	if (!argc)
 		return 0;
 
-	if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))
-		return queue_if_no_path(m, 1, 0);
-	else {
+	do {
+		param_name = shift(as);
+		argc--;
+
+		if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
+			r = queue_if_no_path(m, 1, 0);
+			continue;
+		}
+
+		if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
+		    (argc >= 1)) {
+			r = read_param(_params + 1, shift(as),
+				       &m->pg_init_retries, &ti->error);
+			argc--;
+			continue;
+		}
+
 		ti->error = "Unrecognised multipath feature request";
-		return -EINVAL;
-	}
+		r = -EINVAL;
+	} while (argc && !r);
+
+	return r;
 }
 
 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
@@ -754,8 +805,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 		struct priority_group *pg;
 
 		pg = parse_priority_group(&as, m);
-		if (!pg) {
-			r = -EINVAL;
+		if (IS_ERR(pg)) {
+			r = PTR_ERR(pg);
 			goto bad;
 		}
 
@@ -784,6 +835,7 @@ static void multipath_dtr(struct dm_target *ti)
 {
 	struct multipath *m = (struct multipath *) ti->private;
 
+	flush_workqueue(kmpath_handlerd);
 	flush_workqueue(kmultipathd);
 	free_multipath(m);
 }
@@ -795,17 +847,14 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
 			 union map_info *map_context)
 {
 	int r;
-	struct mpath_io *mpio;
+	struct dm_mpath_io *mpio;
 	struct multipath *m = (struct multipath *) ti->private;
 
-	if (bio_barrier(bio))
-		return -EOPNOTSUPP;
-
 	mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
 	dm_bio_record(&mpio->details, bio);
 
 	map_context->ptr = mpio;
-	bio->bi_rw |= (1 << BIO_RW_FAILFAST);
+	bio->bi_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT);
 	r = map_io(m, bio, mpio, 0);
 	if (r < 0 || r == DM_MAPIO_REQUEUE)
 		mempool_free(mpio, m->mpio_pool);
@@ -823,13 +872,13 @@ static int fail_path(struct pgpath *pgpath)
 
 	spin_lock_irqsave(&m->lock, flags);
 
-	if (!pgpath->path.is_active)
+	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->path.is_active = 0;
+	pgpath->is_active = 0;
 	pgpath->fail_count++;
 
 	m->nr_valid_paths--;
@@ -837,7 +886,11 @@ static int fail_path(struct pgpath *pgpath)
 	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);
+
 	queue_work(kmultipathd, &m->trigger_event);
+	queue_work(kmultipathd, &pgpath->deactivate_path);
 
 out:
 	spin_unlock_irqrestore(&m->lock, flags);
@@ -856,10 +909,10 @@ static int reinstate_path(struct pgpath *pgpath)
 
 	spin_lock_irqsave(&m->lock, flags);
 
-	if (pgpath->path.is_active)
+	if (pgpath->is_active)
 		goto out;
 
-	if (!pgpath->pg->ps.type) {
+	if (!pgpath->pg->ps.type->reinstate_path) {
 		DMWARN("Reinstate path not supported by path selector %s",
 		       pgpath->pg->ps.type->name);
 		r = -EINVAL;
@@ -870,12 +923,15 @@ static int reinstate_path(struct pgpath *pgpath)
 	if (r)
 		goto out;
 
-	pgpath->path.is_active = 1;
+	pgpath->is_active = 1;
 
 	m->current_pgpath = NULL;
 	if (!m->nr_valid_paths++ && m->queue_size)
 		queue_work(kmultipathd, &m->process_queued_ios);
 
+	dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
+		      pgpath->path.dev->name, m->nr_valid_paths);
+
 	queue_work(kmultipathd, &m->trigger_event);
 
 out:
@@ -979,45 +1035,111 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
 }
 
 /*
- * pg_init must call this when it has completed its initialisation
+ * Should we retry pg_init immediately?
  */
-void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
+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(struct dm_path *path, int errors)
 {
 	struct pgpath *pgpath = path_to_pgpath(path);
 	struct priority_group *pg = pgpath->pg;
 	struct multipath *m = pg->m;
 	unsigned long flags;
 
-	/* We insist on failing the path if the PG is already bypassed. */
-	if (err_flags && pg->bypassed)
-		err_flags |= MP_FAIL_PATH;
-
-	if (err_flags & MP_FAIL_PATH)
+	/* device or driver problems */
+	switch (errors) {
+	case SCSI_DH_OK:
+		break;
+	case SCSI_DH_NOSYS:
+		if (!m->hw_handler_name) {
+			errors = 0;
+			break;
+		}
+		DMERR("Cannot failover device because scsi_dh_%s was not "
+		      "loaded.", m->hw_handler_name);
+		/*
+		 * Fail path for now, so we do not ping pong
+		 */
 		fail_path(pgpath);
-
-	if (err_flags & MP_BYPASS_PG)
+		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;
+	/* TODO: For SCSI_DH_RETRY we should wait a couple seconds */
+	case SCSI_DH_RETRY:
+	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 (err_flags) {
+	if (errors) {
+		DMERR("Could not failover device. Error %d.", errors);
 		m->current_pgpath = NULL;
 		m->current_pg = NULL;
-	} else if (!m->pg_init_required)
+	} else if (!m->pg_init_required) {
 		m->queue_io = 0;
+		pg->bypassed = 0;
+	}
 
 	m->pg_init_in_progress = 0;
 	queue_work(kmultipathd, &m->process_queued_ios);
 	spin_unlock_irqrestore(&m->lock, flags);
 }
 
+static void activate_path(struct work_struct *work)
+{
+	int ret;
+	struct multipath *m =
+		container_of(work, struct multipath, activate_path);
+	struct dm_path *path;
+	unsigned long flags;
+
+	spin_lock_irqsave(&m->lock, flags);
+	path = &m->pgpath_to_activate->path;
+	m->pgpath_to_activate = NULL;
+	spin_unlock_irqrestore(&m->lock, flags);
+	if (!path)
+		return;
+	ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
+	pg_init_done(path, ret);
+}
+
 /*
  * end_io handling
  */
 static int do_end_io(struct multipath *m, struct bio *bio,
-		     int error, struct mpath_io *mpio)
+		     int error, struct dm_mpath_io *mpio)
 {
-	struct hw_handler *hwh = &m->hw_handler;
-	unsigned err_flags = MP_FAIL_PATH;	/* Default behavior */
 	unsigned long flags;
 
 	if (!error)
@@ -1044,19 +1166,8 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 	}
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	if (hwh->type && hwh->type->error)
-		err_flags = hwh->type->error(hwh, bio);
-
-	if (mpio->pgpath) {
-		if (err_flags & MP_FAIL_PATH)
-			fail_path(mpio->pgpath);
-
-		if (err_flags & MP_BYPASS_PG)
-			bypass_pg(m, mpio->pgpath->pg, 1);
-	}
-
-	if (err_flags & MP_ERROR_IO)
-		return -EIO;
+	if (mpio->pgpath)
+		fail_path(mpio->pgpath);
 
       requeue:
 	dm_bio_restore(&mpio->details, bio);
@@ -1075,8 +1186,8 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
 			    int error, union map_info *map_context)
 {
-	struct multipath *m = (struct multipath *) ti->private;
-	struct mpath_io *mpio = (struct mpath_io *) map_context->ptr;
+	struct multipath *m = ti->private;
+	struct dm_mpath_io *mpio = map_context->ptr;
 	struct pgpath *pgpath = mpio->pgpath;
 	struct path_selector *ps;
 	int r;
@@ -1141,7 +1252,6 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 	int sz = 0;
 	unsigned long flags;
 	struct multipath *m = (struct multipath *) ti->private;
-	struct hw_handler *hwh = &m->hw_handler;
 	struct priority_group *pg;
 	struct pgpath *p;
 	unsigned pg_num;
@@ -1151,18 +1261,20 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 
 	/* Features */
 	if (type == STATUSTYPE_INFO)
-		DMEMIT("1 %u ", m->queue_size);
-	else if (m->queue_if_no_path)
-		DMEMIT("1 queue_if_no_path ");
-	else
-		DMEMIT("0 ");
+		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);
+		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 (hwh->type && hwh->type->status)
-		sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);
-	else if (!hwh->type || type == STATUSTYPE_INFO)
+	if (!m->hw_handler_name || type == STATUSTYPE_INFO)
 		DMEMIT("0 ");
 	else
-		DMEMIT("1 %s ", hwh->type->name);
+		DMEMIT("1 %s ", m->hw_handler_name);
 
 	DMEMIT("%u ", m->nr_priority_groups);
 
@@ -1199,7 +1311,7 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 
 			list_for_each_entry(p, &pg->pgpaths, list) {
 				DMEMIT("%s %s %u ", p->path.dev->name,
-				       p->path.is_active ? "A" : "F",
+				       p->is_active ? "A" : "F",
 				       p->fail_count);
 				if (pg->ps.type->status)
 					sz += pg->ps.type->status(&pg->ps,
@@ -1288,19 +1400,15 @@ error:
 	return -EINVAL;
 }
 
-static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
-			   struct file *filp, unsigned int cmd,
+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;
-	struct file fake_file = {};
-	struct dentry fake_dentry = {};
 	int r = 0;
 
-	fake_file.f_path.dentry = &fake_dentry;
-
 	spin_lock_irqsave(&m->lock, flags);
 
 	if (!m->current_pgpath)
@@ -1308,8 +1416,7 @@ static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
 
 	if (m->current_pgpath) {
 		bdev = m->current_pgpath->path.dev->bdev;
-		fake_dentry.d_inode = bdev->bd_inode;
-		fake_file.f_mode = m->current_pgpath->path.dev->mode;
+		mode = m->current_pgpath->path.dev->mode;
 	}
 
 	if (m->queue_io)
@@ -1319,8 +1426,7 @@ static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
 
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	return r ? : blkdev_driver_ioctl(bdev->bd_inode, &fake_file,
-					 bdev->bd_disk, cmd, arg);
+	return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 }
 
 /*-----------------------------------------------------------------
@@ -1346,22 +1452,35 @@ static int __init dm_multipath_init(void)
 	int r;
 
 	/* allocate a slab for the dm_ios */
-	_mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io),
-					0, 0, NULL, NULL);
+	_mpio_cache = KMEM_CACHE(dm_mpath_io, 0);
 	if (!_mpio_cache)
 		return -ENOMEM;
 
 	r = dm_register_target(&multipath_target);
 	if (r < 0) {
-		DMERR("%s: register failed %d", multipath_target.name, r);
+		DMERR("register failed %d", r);
 		kmem_cache_destroy(_mpio_cache);
 		return -EINVAL;
 	}
 
 	kmultipathd = create_workqueue("kmpathd");
 	if (!kmultipathd) {
-		DMERR("%s: failed to create workqueue kmpathd",
-				multipath_target.name);
+		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 = create_singlethread_workqueue("kmpath_handlerd");
+	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;
@@ -1378,17 +1497,15 @@ static void __exit dm_multipath_exit(void)
 {
 	int r;
 
+	destroy_workqueue(kmpath_handlerd);
 	destroy_workqueue(kmultipathd);
 
 	r = dm_unregister_target(&multipath_target);
 	if (r < 0)
-		DMERR("%s: target unregister failed %d",
-		      multipath_target.name, r);
+		DMERR("target unregister failed %d", r);
 	kmem_cache_destroy(_mpio_cache);
 }
 
-EXPORT_SYMBOL_GPL(dm_pg_init_complete);
-
 module_init(dm_multipath_init);
 module_exit(dm_multipath_exit);