Merge commit 'scsi/master'

30 files changed, 1955 insertions, 1673 deletions

diff --git a/Documentation/scsi/aacraid.txt b/Documentation/scsi/aacraid.txt
index d16011a8618e..709ca991a451 100644
--- a/Documentation/scsi/aacraid.txt
+++ b/Documentation/scsi/aacraid.txt
@@ -56,19 +56,33 @@ Supported Cards/Chipsets
 	9005:0285:9005:02d1	Adaptec	5405 (Voodoo40)
 	9005:0285:15d9:02d2	SMC	AOC-USAS-S8i-LP
 	9005:0285:15d9:02d3	SMC	AOC-USAS-S8iR-LP
-	9005:0285:9005:02d4	Adaptec	2045 (Voodoo04 Lite)
-	9005:0285:9005:02d5	Adaptec	2405 (Voodoo40 Lite)
-	9005:0285:9005:02d6	Adaptec	2445 (Voodoo44 Lite)
-	9005:0285:9005:02d7	Adaptec	2805 (Voodoo80 Lite)
+	9005:0285:9005:02d4	Adaptec	ASR-2045 (Voodoo04 Lite)
+	9005:0285:9005:02d5	Adaptec	ASR-2405 (Voodoo40 Lite)
+	9005:0285:9005:02d6	Adaptec	ASR-2445 (Voodoo44 Lite)
+	9005:0285:9005:02d7	Adaptec	ASR-2805 (Voodoo80 Lite)
+	9005:0285:9005:02d8	Adaptec	5405G (Voodoo40 PM)
+	9005:0285:9005:02d9	Adaptec	5445G (Voodoo44 PM)
+	9005:0285:9005:02da	Adaptec	5805G (Voodoo80 PM)
+	9005:0285:9005:02db	Adaptec	5085G (Voodoo08 PM)
+	9005:0285:9005:02dc	Adaptec	51245G (Voodoo124 PM)
+	9005:0285:9005:02dd	Adaptec	51645G (Voodoo164 PM)
+	9005:0285:9005:02de	Adaptec	52445G (Voodoo244 PM)
+	9005:0285:9005:02df	Adaptec	ASR-2045G (Voodoo04 Lite PM)
+	9005:0285:9005:02e0	Adaptec	ASR-2405G (Voodoo40 Lite PM)
+	9005:0285:9005:02e1	Adaptec	ASR-2445G (Voodoo44 Lite PM)
+	9005:0285:9005:02e2	Adaptec	ASR-2805G (Voodoo80 Lite PM)
 	1011:0046:9005:0364	Adaptec	5400S (Mustang)
+	1011:0046:9005:0365	Adaptec	5400S (Mustang)
 	9005:0287:9005:0800	Adaptec	Themisto (Jupiter)
 	9005:0200:9005:0200	Adaptec	Themisto (Jupiter)
 	9005:0286:9005:0800	Adaptec	Callisto (Jupiter)
 	1011:0046:9005:1364	Dell	PERC 2/QC (Quad Channel, Mustang)
+	1011:0046:9005:1365	Dell	PERC 2/QC (Quad Channel, Mustang)
 	1028:0001:1028:0001	Dell	PERC 2/Si (Iguana)
 	1028:0003:1028:0003	Dell	PERC 3/Si (SlimFast)
 	1028:0002:1028:0002	Dell	PERC 3/Di (Opal)
-	1028:0004:1028:0004	Dell	PERC 3/DiF (Iguana)
+	1028:0004:1028:0004	Dell	PERC 3/SiF (Iguana)
+	1028:0004:1028:00d0	Dell	PERC 3/DiF (Iguana)
 	1028:0002:1028:00d1	Dell	PERC 3/DiV (Viper)
 	1028:0002:1028:00d9	Dell	PERC 3/DiL (Lexus)
 	1028:000a:1028:0106	Dell	PERC 3/DiJ (Jaguar)
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 610af916891e..b4a3c7d1451d 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -252,27 +252,10 @@ config DM_ZERO
 config DM_MULTIPATH
 	tristate "Multipath target"
 	depends on BLK_DEV_DM
+	select SCSI_DH
 	---help---
 	  Allow volume managers to support multipath hardware.
 
-config DM_MULTIPATH_EMC
-	tristate "EMC CX/AX multipath support"
-	depends on DM_MULTIPATH && BLK_DEV_DM
-	---help---
-	  Multipath support for EMC CX/AX series hardware.
-
-config DM_MULTIPATH_RDAC
-	tristate "LSI/Engenio RDAC multipath support (EXPERIMENTAL)"
-	depends on DM_MULTIPATH && BLK_DEV_DM && SCSI && EXPERIMENTAL
-	---help---
-	  Multipath support for LSI/Engenio RDAC.
-
-config DM_MULTIPATH_HP
-        tristate "HP MSA multipath support (EXPERIMENTAL)"
-        depends on DM_MULTIPATH && BLK_DEV_DM && SCSI && EXPERIMENTAL
-        ---help---
-          Multipath support for HP MSA (Active/Passive) series hardware.
-
 config DM_DELAY
 	tristate "I/O delaying target (EXPERIMENTAL)"
 	depends on BLK_DEV_DM && EXPERIMENTAL
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 7be09eeea293..f1ef33dfd8cf 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -4,11 +4,9 @@
 
 dm-mod-objs	:= dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
 		   dm-ioctl.o dm-io.o dm-kcopyd.o
-dm-multipath-objs := dm-hw-handler.o dm-path-selector.o dm-mpath.o
+dm-multipath-objs := dm-path-selector.o dm-mpath.o
 dm-snapshot-objs := dm-snap.o dm-exception-store.o
 dm-mirror-objs	:= dm-raid1.o
-dm-rdac-objs	:= dm-mpath-rdac.o
-dm-hp-sw-objs	:= dm-mpath-hp-sw.o
 md-mod-objs     := md.o bitmap.o
 raid456-objs	:= raid5.o raid6algos.o raid6recov.o raid6tables.o \
 		   raid6int1.o raid6int2.o raid6int4.o \
@@ -35,9 +33,6 @@ obj-$(CONFIG_BLK_DEV_DM)	+= dm-mod.o
 obj-$(CONFIG_DM_CRYPT)		+= dm-crypt.o
 obj-$(CONFIG_DM_DELAY)		+= dm-delay.o
 obj-$(CONFIG_DM_MULTIPATH)	+= dm-multipath.o dm-round-robin.o
-obj-$(CONFIG_DM_MULTIPATH_EMC)	+= dm-emc.o
-obj-$(CONFIG_DM_MULTIPATH_HP)	+= dm-hp-sw.o
-obj-$(CONFIG_DM_MULTIPATH_RDAC)	+= dm-rdac.o
 obj-$(CONFIG_DM_SNAPSHOT)	+= dm-snapshot.o
 obj-$(CONFIG_DM_MIRROR)		+= dm-mirror.o dm-log.o
 obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
diff --git a/drivers/md/dm-emc.c b/drivers/md/dm-emc.c
deleted file mode 100644
index 3ea5ad4b7805..000000000000
--- a/drivers/md/dm-emc.c
+++ /dev/null
@@ -1,345 +0,0 @@
-/*
- * Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- *
- * Multipath support for EMC CLARiiON AX/CX-series hardware.
- */
-
-#include "dm.h"
-#include "dm-hw-handler.h"
-#include <scsi/scsi.h>
-#include <scsi/scsi_cmnd.h>
-
-#define DM_MSG_PREFIX "multipath emc"
-
-struct emc_handler {
-	spinlock_t lock;
-
-	/* Whether we should send the short trespass command (FC-series)
-	 * or the long version (default for AX/CX CLARiiON arrays). */
-	unsigned short_trespass;
-	/* Whether or not to honor SCSI reservations when initiating a
-	 * switch-over. Default: Don't. */
-	unsigned hr;
-
-	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
-};
-
-#define TRESPASS_PAGE 0x22
-#define EMC_FAILOVER_TIMEOUT (60 * HZ)
-
-/* Code borrowed from dm-lsi-rdac by Mike Christie */
-
-static inline void free_bio(struct bio *bio)
-{
-	__free_page(bio->bi_io_vec[0].bv_page);
-	bio_put(bio);
-}
-
-static void emc_endio(struct bio *bio, int error)
-{
-	struct dm_path *path = bio->bi_private;
-
-	/* We also need to look at the sense keys here whether or not to
-	 * switch to the next PG etc.
-	 *
-	 * For now simple logic: either it works or it doesn't.
-	 */
-	if (error)
-		dm_pg_init_complete(path, MP_FAIL_PATH);
-	else
-		dm_pg_init_complete(path, 0);
-
-	/* request is freed in block layer */
-	free_bio(bio);
-}
-
-static struct bio *get_failover_bio(struct dm_path *path, unsigned data_size)
-{
-	struct bio *bio;
-	struct page *page;
-
-	bio = bio_alloc(GFP_ATOMIC, 1);
-	if (!bio) {
-		DMERR("get_failover_bio: bio_alloc() failed.");
-		return NULL;
-	}
-
-	bio->bi_rw |= (1 << BIO_RW);
-	bio->bi_bdev = path->dev->bdev;
-	bio->bi_sector = 0;
-	bio->bi_private = path;
-	bio->bi_end_io = emc_endio;
-
-	page = alloc_page(GFP_ATOMIC);
-	if (!page) {
-		DMERR("get_failover_bio: alloc_page() failed.");
-		bio_put(bio);
-		return NULL;
-	}
-
-	if (bio_add_page(bio, page, data_size, 0) != data_size) {
-		DMERR("get_failover_bio: bio_add_page() failed.");
-		__free_page(page);
-		bio_put(bio);
-		return NULL;
-	}
-
-	return bio;
-}
-
-static struct request *get_failover_req(struct emc_handler *h,
-					struct bio *bio, struct dm_path *path)
-{
-	struct request *rq;
-	struct block_device *bdev = bio->bi_bdev;
-	struct request_queue *q = bdev_get_queue(bdev);
-
-	/* FIXME: Figure out why it fails with GFP_ATOMIC. */
-	rq = blk_get_request(q, WRITE, __GFP_WAIT);
-	if (!rq) {
-		DMERR("get_failover_req: blk_get_request failed");
-		return NULL;
-	}
-
-	blk_rq_append_bio(q, rq, bio);
-
-	rq->sense = h->sense;
-	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-	rq->sense_len = 0;
-
-	rq->timeout = EMC_FAILOVER_TIMEOUT;
-	rq->cmd_type = REQ_TYPE_BLOCK_PC;
-	rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
-
-	return rq;
-}
-
-static struct request *emc_trespass_get(struct emc_handler *h,
-					struct dm_path *path)
-{
-	struct bio *bio;
-	struct request *rq;
-	unsigned char *page22;
-	unsigned char long_trespass_pg[] = {
-		0, 0, 0, 0,
-		TRESPASS_PAGE,        /* Page code */
-		0x09,                 /* Page length - 2 */
-		h->hr ? 0x01 : 0x81,  /* Trespass code + Honor reservation bit */
-		0xff, 0xff,           /* Trespass target */
-		0, 0, 0, 0, 0, 0      /* Reserved bytes / unknown */
-		};
-	unsigned char short_trespass_pg[] = {
-		0, 0, 0, 0,
-		TRESPASS_PAGE,        /* Page code */
-		0x02,                 /* Page length - 2 */
-		h->hr ? 0x01 : 0x81,  /* Trespass code + Honor reservation bit */
-		0xff,                 /* Trespass target */
-		};
-	unsigned data_size = h->short_trespass ? sizeof(short_trespass_pg) :
-				sizeof(long_trespass_pg);
-
-	/* get bio backing */
-	if (data_size > PAGE_SIZE)
-		/* this should never happen */
-		return NULL;
-
-	bio = get_failover_bio(path, data_size);
-	if (!bio) {
-		DMERR("emc_trespass_get: no bio");
-		return NULL;
-	}
-
-	page22 = (unsigned char *)bio_data(bio);
-	memset(page22, 0, data_size);
-
-	memcpy(page22, h->short_trespass ?
-		short_trespass_pg : long_trespass_pg, data_size);
-
-	/* get request for block layer packet command */
-	rq = get_failover_req(h, bio, path);
-	if (!rq) {
-		DMERR("emc_trespass_get: no rq");
-		free_bio(bio);
-		return NULL;
-	}
-
-	/* Prepare the command. */
-	rq->cmd[0] = MODE_SELECT;
-	rq->cmd[1] = 0x10;
-	rq->cmd[4] = data_size;
-	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
-
-	return rq;
-}
-
-static void emc_pg_init(struct hw_handler *hwh, unsigned bypassed,
-			struct dm_path *path)
-{
-	struct request *rq;
-	struct request_queue *q = bdev_get_queue(path->dev->bdev);
-
-	/*
-	 * We can either blindly init the pg (then look at the sense),
-	 * or we can send some commands to get the state here (then
-	 * possibly send the fo cmnd), or we can also have the
-	 * initial state passed into us and then get an update here.
-	 */
-	if (!q) {
-		DMINFO("emc_pg_init: no queue");
-		goto fail_path;
-	}
-
-	/* FIXME: The request should be pre-allocated. */
-	rq = emc_trespass_get(hwh->context, path);
-	if (!rq) {
-		DMERR("emc_pg_init: no rq");
-		goto fail_path;
-	}
-
-	DMINFO("emc_pg_init: sending switch-over command");
-	elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
-	return;
-
-fail_path:
-	dm_pg_init_complete(path, MP_FAIL_PATH);
-}
-
-static struct emc_handler *alloc_emc_handler(void)
-{
-	struct emc_handler *h = kzalloc(sizeof(*h), GFP_KERNEL);
-
-	if (h)
-		spin_lock_init(&h->lock);
-
-	return h;
-}
-
-static int emc_create(struct hw_handler *hwh, unsigned argc, char **argv)
-{
-	struct emc_handler *h;
-	unsigned hr, short_trespass;
-
-	if (argc == 0) {
-		/* No arguments: use defaults */
-		hr = 0;
-		short_trespass = 0;
-	} else if (argc != 2) {
-		DMWARN("incorrect number of arguments");
-		return -EINVAL;
-	} else {
-		if ((sscanf(argv[0], "%u", &short_trespass) != 1)
-			|| (short_trespass > 1)) {
-			DMWARN("invalid trespass mode selected");
-			return -EINVAL;
-		}
-
-		if ((sscanf(argv[1], "%u", &hr) != 1)
-			|| (hr > 1)) {
-			DMWARN("invalid honor reservation flag selected");
-			return -EINVAL;
-		}
-	}
-
-	h = alloc_emc_handler();
-	if (!h)
-		return -ENOMEM;
-
-	hwh->context = h;
-
-	if ((h->short_trespass = short_trespass))
-		DMWARN("short trespass command will be send");
-	else
-		DMWARN("long trespass command will be send");
-
-	if ((h->hr = hr))
-		DMWARN("honor reservation bit will be set");
-	else
-		DMWARN("honor reservation bit will not be set (default)");
-
-	return 0;
-}
-
-static void emc_destroy(struct hw_handler *hwh)
-{
-	struct emc_handler *h = (struct emc_handler *) hwh->context;
-
-	kfree(h);
-	hwh->context = NULL;
-}
-
-static unsigned emc_error(struct hw_handler *hwh, struct bio *bio)
-{
-	/* FIXME: Patch from axboe still missing */
-#if 0
-	int sense;
-
-	if (bio->bi_error & BIO_SENSE) {
-		sense = bio->bi_error & 0xffffff; /* sense key / asc / ascq */
-
-		if (sense == 0x020403) {
-			/* LUN Not Ready - Manual Intervention Required
-			 * indicates this is a passive path.
-			 *
-			 * FIXME: However, if this is seen and EVPD C0
-			 * indicates that this is due to a NDU in
-			 * progress, we should set FAIL_PATH too.
-			 * This indicates we might have to do a SCSI
-			 * inquiry in the end_io path. Ugh. */
-			return MP_BYPASS_PG | MP_RETRY_IO;
-		} else if (sense == 0x052501) {
-			/* An array based copy is in progress. Do not
-			 * fail the path, do not bypass to another PG,
-			 * do not retry. Fail the IO immediately.
-			 * (Actually this is the same conclusion as in
-			 * the default handler, but lets make sure.) */
-			return 0;
-		} else if (sense == 0x062900) {
-			/* Unit Attention Code. This is the first IO
-			 * to the new path, so just retry. */
-			return MP_RETRY_IO;
-		}
-	}
-#endif
-
-	/* Try default handler */
-	return dm_scsi_err_handler(hwh, bio);
-}
-
-static struct hw_handler_type emc_hwh = {
-	.name = "emc",
-	.module = THIS_MODULE,
-	.create = emc_create,
-	.destroy = emc_destroy,
-	.pg_init = emc_pg_init,
-	.error = emc_error,
-};
-
-static int __init dm_emc_init(void)
-{
-	int r = dm_register_hw_handler(&emc_hwh);
-
-	if (r < 0)
-		DMERR("register failed %d", r);
-
-	DMINFO("version 0.0.3 loaded");
-
-	return r;
-}
-
-static void __exit dm_emc_exit(void)
-{
-	int r = dm_unregister_hw_handler(&emc_hwh);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
-}
-
-module_init(dm_emc_init);
-module_exit(dm_emc_exit);
-
-MODULE_DESCRIPTION(DM_NAME " EMC CX/AX/FC-family multipath");
-MODULE_AUTHOR("Lars Marowsky-Bree <lmb@suse.de>");
-MODULE_LICENSE("GPL");
diff --git a/drivers/md/dm-hw-handler.c b/drivers/md/dm-hw-handler.c
deleted file mode 100644
index 2ee84d8aa0bf..000000000000
--- a/drivers/md/dm-hw-handler.c
+++ /dev/null
@@ -1,213 +0,0 @@
-/*
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- *
- * Multipath hardware handler registration.
- */
-
-#include "dm.h"
-#include "dm-hw-handler.h"
-
-#include <linux/slab.h>
-
-struct hwh_internal {
-	struct hw_handler_type hwht;
-
-	struct list_head list;
-	long use;
-};
-
-#define hwht_to_hwhi(__hwht) container_of((__hwht), struct hwh_internal, hwht)
-
-static LIST_HEAD(_hw_handlers);
-static DECLARE_RWSEM(_hwh_lock);
-
-static struct hwh_internal *__find_hw_handler_type(const char *name)
-{
-	struct hwh_internal *hwhi;
-
-	list_for_each_entry(hwhi, &_hw_handlers, list) {
-		if (!strcmp(name, hwhi->hwht.name))
-			return hwhi;
-	}
-
-	return NULL;
-}
-
-static struct hwh_internal *get_hw_handler(const char *name)
-{
-	struct hwh_internal *hwhi;
-
-	down_read(&_hwh_lock);
-	hwhi = __find_hw_handler_type(name);
-	if (hwhi) {
-		if ((hwhi->use == 0) && !try_module_get(hwhi->hwht.module))
-			hwhi = NULL;
-		else
-			hwhi->use++;
-	}
-	up_read(&_hwh_lock);
-
-	return hwhi;
-}
-
-struct hw_handler_type *dm_get_hw_handler(const char *name)
-{
-	struct hwh_internal *hwhi;
-
-	if (!name)
-		return NULL;
-
-	hwhi = get_hw_handler(name);
-	if (!hwhi) {
-		request_module("dm-%s", name);
-		hwhi = get_hw_handler(name);
-	}
-
-	return hwhi ? &hwhi->hwht : NULL;
-}
-
-void dm_put_hw_handler(struct hw_handler_type *hwht)
-{
-	struct hwh_internal *hwhi;
-
-	if (!hwht)
-		return;
-
-	down_read(&_hwh_lock);
-	hwhi = __find_hw_handler_type(hwht->name);
-	if (!hwhi)
-		goto out;
-
-	if (--hwhi->use == 0)
-		module_put(hwhi->hwht.module);
-
-	BUG_ON(hwhi->use < 0);
-
-      out:
-	up_read(&_hwh_lock);
-}
-
-static struct hwh_internal *_alloc_hw_handler(struct hw_handler_type *hwht)
-{
-	struct hwh_internal *hwhi = kzalloc(sizeof(*hwhi), GFP_KERNEL);
-
-	if (hwhi)
-		hwhi->hwht = *hwht;
-
-	return hwhi;
-}
-
-int dm_register_hw_handler(struct hw_handler_type *hwht)
-{
-	int r = 0;
-	struct hwh_internal *hwhi = _alloc_hw_handler(hwht);
-
-	if (!hwhi)
-		return -ENOMEM;
-
-	down_write(&_hwh_lock);
-
-	if (__find_hw_handler_type(hwht->name)) {
-		kfree(hwhi);
-		r = -EEXIST;
-	} else
-		list_add(&hwhi->list, &_hw_handlers);
-
-	up_write(&_hwh_lock);
-
-	return r;
-}
-
-int dm_unregister_hw_handler(struct hw_handler_type *hwht)
-{
-	struct hwh_internal *hwhi;
-
-	down_write(&_hwh_lock);
-
-	hwhi = __find_hw_handler_type(hwht->name);
-	if (!hwhi) {
-		up_write(&_hwh_lock);
-		return -EINVAL;
-	}
-
-	if (hwhi->use) {
-		up_write(&_hwh_lock);
-		return -ETXTBSY;
-	}
-
-	list_del(&hwhi->list);
-
-	up_write(&_hwh_lock);
-
-	kfree(hwhi);
-
-	return 0;
-}
-
-unsigned dm_scsi_err_handler(struct hw_handler *hwh, struct bio *bio)
-{
-#if 0
-	int sense_key, asc, ascq;
-
-	if (bio->bi_error & BIO_SENSE) {
-		/* FIXME: This is just an initial guess. */
-		/* key / asc / ascq */
-		sense_key = (bio->bi_error >> 16) & 0xff;
-		asc = (bio->bi_error >> 8) & 0xff;
-		ascq = bio->bi_error & 0xff;
-
-		switch (sense_key) {
-			/* This block as a whole comes from the device.
-			 * So no point retrying on another path. */
-		case 0x03:	/* Medium error */
-		case 0x05:	/* Illegal request */
-		case 0x07:	/* Data protect */
-		case 0x08:	/* Blank check */
-		case 0x0a:	/* copy aborted */
-		case 0x0c:	/* obsolete - no clue ;-) */
-		case 0x0d:	/* volume overflow */
-		case 0x0e:	/* data miscompare */
-		case 0x0f:	/* reserved - no idea either. */
-			return MP_ERROR_IO;
-
-			/* For these errors it's unclear whether they
-			 * come from the device or the controller.
-			 * So just lets try a different path, and if
-			 * it eventually succeeds, user-space will clear
-			 * the paths again... */
-		case 0x02:	/* Not ready */
-		case 0x04:	/* Hardware error */
-		case 0x09:	/* vendor specific */
-		case 0x0b:	/* Aborted command */
-			return MP_FAIL_PATH;
-
-		case 0x06:	/* Unit attention - might want to decode */
-			if (asc == 0x04 && ascq == 0x01)
-				/* "Unit in the process of
-				 * becoming ready" */
-				return 0;
-			return MP_FAIL_PATH;
-
-			/* FIXME: For Unit Not Ready we may want
-			 * to have a generic pg activation
-			 * feature (START_UNIT). */
-
-			/* Should these two ever end up in the
-			 * error path? I don't think so. */
-		case 0x00:	/* No sense */
-		case 0x01:	/* Recovered error */
-			return 0;
-		}
-	}
-#endif
-
-	/* We got no idea how to decode the other kinds of errors ->
-	 * assume generic error condition. */
-	return MP_FAIL_PATH;
-}
-
-EXPORT_SYMBOL_GPL(dm_register_hw_handler);
-EXPORT_SYMBOL_GPL(dm_unregister_hw_handler);
-EXPORT_SYMBOL_GPL(dm_scsi_err_handler);
diff --git a/drivers/md/dm-hw-handler.h b/drivers/md/dm-hw-handler.h
deleted file mode 100644
index 46809dcb121a..000000000000
--- a/drivers/md/dm-hw-handler.h
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- *
- * Multipath hardware handler registration.
- */
-
-#ifndef	DM_HW_HANDLER_H
-#define	DM_HW_HANDLER_H
-
-#include <linux/device-mapper.h>
-
-#include "dm-mpath.h"
-
-struct hw_handler_type;
-struct hw_handler {
-	struct hw_handler_type *type;
-	struct mapped_device *md;
-	void *context;
-};
-
-/*
- * Constructs a hardware handler object, takes custom arguments
- */
-/* Information about a hardware handler type */
-struct hw_handler_type {
-	char *name;
-	struct module *module;
-
-	int (*create) (struct hw_handler *handler, unsigned int argc,
-		       char **argv);
-	void (*destroy) (struct hw_handler *hwh);
-
-	void (*pg_init) (struct hw_handler *hwh, unsigned bypassed,
-			 struct dm_path *path);
-	unsigned (*error) (struct hw_handler *hwh, struct bio *bio);
-	int (*status) (struct hw_handler *hwh, status_type_t type,
-		       char *result, unsigned int maxlen);
-};
-
-/* Register a hardware handler */
-int dm_register_hw_handler(struct hw_handler_type *type);
-
-/* Unregister a hardware handler */
-int dm_unregister_hw_handler(struct hw_handler_type *type);
-
-/* Returns a registered hardware handler type */
-struct hw_handler_type *dm_get_hw_handler(const char *name);
-
-/* Releases a hardware handler  */
-void dm_put_hw_handler(struct hw_handler_type *hwht);
-
-/* Default err function */
-unsigned dm_scsi_err_handler(struct hw_handler *hwh, struct bio *bio);
-
-/* Error flags for err and dm_pg_init_complete */
-#define MP_FAIL_PATH 1
-#define MP_BYPASS_PG 2
-#define MP_ERROR_IO  4	/* Don't retry this I/O */
-#define MP_RETRY 8
-
-#endif
diff --git a/drivers/md/dm-mpath-hp-sw.c b/drivers/md/dm-mpath-hp-sw.c
deleted file mode 100644
index b63a0ab37c53..000000000000
--- a/drivers/md/dm-mpath-hp-sw.c
+++ /dev/null
@@ -1,247 +0,0 @@
-/*
- * Copyright (C) 2005 Mike Christie, All rights reserved.
- * Copyright (C) 2007 Red Hat, Inc. All rights reserved.
- * Authors: Mike Christie
- *          Dave Wysochanski
- *
- * This file is released under the GPL.
- *
- * This module implements the specific path activation code for
- * HP StorageWorks and FSC FibreCat Asymmetric (Active/Passive)
- * storage arrays.
- * These storage arrays have controller-based failover, not
- * LUN-based failover.  However, LUN-based failover is the design
- * of dm-multipath. Thus, this module is written for LUN-based failover.
- */
-#include <linux/blkdev.h>
-#include <linux/list.h>
-#include <linux/types.h>
-#include <scsi/scsi.h>
-#include <scsi/scsi_cmnd.h>
-#include <scsi/scsi_dbg.h>
-
-#include "dm.h"
-#include "dm-hw-handler.h"
-
-#define DM_MSG_PREFIX "multipath hp-sw"
-#define DM_HP_HWH_NAME "hp-sw"
-#define DM_HP_HWH_VER "1.0.0"
-
-struct hp_sw_context {
-	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
-};
-
-/*
- * hp_sw_error_is_retryable - Is an HP-specific check condition retryable?
- * @req: path activation request
- *
- * Examine error codes of request and determine whether the error is retryable.
- * Some error codes are already retried by scsi-ml (see
- * scsi_decide_disposition), but some HP specific codes are not.
- * The intent of this routine is to supply the logic for the HP specific
- * check conditions.
- *
- * Returns:
- *  1 - command completed with retryable error
- *  0 - command completed with non-retryable error
- *
- * Possible optimizations
- * 1. More hardware-specific error codes
- */
-static int hp_sw_error_is_retryable(struct request *req)
-{
-	/*
-	 * NOT_READY is known to be retryable
-	 * For now we just dump out the sense data and call it retryable
-	 */
-	if (status_byte(req->errors) == CHECK_CONDITION)
-		__scsi_print_sense(DM_HP_HWH_NAME, req->sense, req->sense_len);
-
-	/*
-	 * At this point we don't have complete information about all the error
-	 * codes from this hardware, so we are just conservative and retry
-	 * when in doubt.
-	 */
-	return 1;
-}
-
-/*
- * hp_sw_end_io - Completion handler for HP path activation.
- * @req: path activation request
- * @error: scsi-ml error
- *
- *  Check sense data, free request structure, and notify dm that
- *  pg initialization has completed.
- *
- * Context: scsi-ml softirq
- *
- */
-static void hp_sw_end_io(struct request *req, int error)
-{
-	struct dm_path *path = req->end_io_data;
-	unsigned err_flags = 0;
-
-	if (!error) {
-		DMDEBUG("%s path activation command - success",
-			path->dev->name);
-		goto out;
-	}
-
-	if (hp_sw_error_is_retryable(req)) {
-		DMDEBUG("%s path activation command - retry",
-			path->dev->name);
-		err_flags = MP_RETRY;
-		goto out;
-	}
-
-	DMWARN("%s path activation fail - error=0x%x",
-	       path->dev->name, error);
-	err_flags = MP_FAIL_PATH;
-
-out:
-	req->end_io_data = NULL;
-	__blk_put_request(req->q, req);
-	dm_pg_init_complete(path, err_flags);
-}
-
-/*
- * hp_sw_get_request - Allocate an HP specific path activation request
- * @path: path on which request will be sent (needed for request queue)
- *
- * The START command is used for path activation request.
- * These arrays are controller-based failover, not LUN based.
- * One START command issued to a single path will fail over all
- * LUNs for the same controller.
- *
- * Possible optimizations
- * 1. Make timeout configurable
- * 2. Preallocate request
- */
-static struct request *hp_sw_get_request(struct dm_path *path)
-{
-	struct request *req;
-	struct block_device *bdev = path->dev->bdev;
-	struct request_queue *q = bdev_get_queue(bdev);
-	struct hp_sw_context *h = path->hwhcontext;
-
-	req = blk_get_request(q, WRITE, GFP_NOIO);
-	if (!req)
-		goto out;
-
-	req->timeout = 60 * HZ;
-
-	req->errors = 0;
-	req->cmd_type = REQ_TYPE_BLOCK_PC;
-	req->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
-	req->end_io_data = path;
-	req->sense = h->sense;
-	memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
-
-	req->cmd[0] = START_STOP;
-	req->cmd[4] = 1;
-	req->cmd_len = COMMAND_SIZE(req->cmd[0]);
-
-out:
-	return req;
-}
-
-/*
- * hp_sw_pg_init - HP path activation implementation.
- * @hwh: hardware handler specific data
- * @bypassed: unused; is the path group bypassed? (see dm-mpath.c)
- * @path: path to send initialization command
- *
- * Send an HP-specific path activation command on 'path'.
- * Do not try to optimize in any way, just send the activation command.
- * More than one path activation command may be sent to the same controller.
- * This seems to work fine for basic failover support.
- *
- * Possible optimizations
- * 1. Detect an in-progress activation request and avoid submitting another one
- * 2. Model the controller and only send a single activation request at a time
- * 3. Determine the state of a path before sending an activation request
- *
- * Context: kmpathd (see process_queued_ios() in dm-mpath.c)
- */
-static void hp_sw_pg_init(struct hw_handler *hwh, unsigned bypassed,
-			  struct dm_path *path)
-{
-	struct request *req;
-	struct hp_sw_context *h;
-
-	path->hwhcontext = hwh->context;
-	h = hwh->context;
-
-	req = hp_sw_get_request(path);
-	if (!req) {
-		DMERR("%s path activation command - allocation fail",
-		      path->dev->name);
-		goto retry;
-	}
-
-	DMDEBUG("%s path activation command - sent", path->dev->name);
-
-	blk_execute_rq_nowait(req->q, NULL, req, 1, hp_sw_end_io);
-	return;
-
-retry:
-	dm_pg_init_complete(path, MP_RETRY);
-}
-
-static int hp_sw_create(struct hw_handler *hwh, unsigned argc, char **argv)
-{
-	struct hp_sw_context *h;
-
-	h = kmalloc(sizeof(*h), GFP_KERNEL);
-	if (!h)
-		return -ENOMEM;
-
-	hwh->context = h;
-
-	return 0;
-}
-
-static void hp_sw_destroy(struct hw_handler *hwh)
-{
-	struct hp_sw_context *h = hwh->context;
-
-	kfree(h);
-}
-
-static struct hw_handler_type hp_sw_hwh = {
-	.name = DM_HP_HWH_NAME,
-	.module = THIS_MODULE,
-	.create = hp_sw_create,
-	.destroy = hp_sw_destroy,
-	.pg_init = hp_sw_pg_init,
-};
-
-static int __init hp_sw_init(void)
-{
-	int r;
-
-	r = dm_register_hw_handler(&hp_sw_hwh);
-	if (r < 0)
-		DMERR("register failed %d", r);
-	else
-		DMINFO("version " DM_HP_HWH_VER " loaded");
-
-	return r;
-}
-
-static void __exit hp_sw_exit(void)
-{
-	int r;
-
-	r = dm_unregister_hw_handler(&hp_sw_hwh);
-	if (r < 0)
-		DMERR("unregister failed %d", r);
-}
-
-module_init(hp_sw_init);
-module_exit(hp_sw_exit);
-
-MODULE_DESCRIPTION("DM Multipath HP StorageWorks / FSC FibreCat (A/P) support");
-MODULE_AUTHOR("Mike Christie, Dave Wysochanski <dm-devel@redhat.com>");
-MODULE_LICENSE("GPL");
-MODULE_VERSION(DM_HP_HWH_VER);
diff --git a/drivers/md/dm-mpath-rdac.c b/drivers/md/dm-mpath-rdac.c
deleted file mode 100644
index 95e77734880a..000000000000
--- a/drivers/md/dm-mpath-rdac.c
+++ /dev/null
@@ -1,700 +0,0 @@
-/*
- * Engenio/LSI RDAC DM HW handler
- *
- * Copyright (C) 2005 Mike Christie. All rights reserved.
- * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- */
-#include <scsi/scsi.h>
-#include <scsi/scsi_cmnd.h>
-#include <scsi/scsi_eh.h>
-
-#define DM_MSG_PREFIX "multipath rdac"
-
-#include "dm.h"
-#include "dm-hw-handler.h"
-
-#define RDAC_DM_HWH_NAME "rdac"
-#define RDAC_DM_HWH_VER "0.4"
-
-/*
- * LSI mode page stuff
- *
- * These struct definitions and the forming of the
- * mode page were taken from the LSI RDAC 2.4 GPL'd
- * driver, and then converted to Linux conventions.
- */
-#define RDAC_QUIESCENCE_TIME 20;
-/*
- * Page Codes
- */
-#define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
-
-/*
- * Controller modes definitions
- */
-#define RDAC_MODE_TRANSFER_ALL_LUNS		0x01
-#define RDAC_MODE_TRANSFER_SPECIFIED_LUNS	0x02
-
-/*
- * RDAC Options field
- */
-#define RDAC_FORCED_QUIESENCE 0x02
-
-#define RDAC_FAILOVER_TIMEOUT (60 * HZ)
-
-struct rdac_mode_6_hdr {
-	u8	data_len;
-	u8	medium_type;
-	u8	device_params;
-	u8	block_desc_len;
-};
-
-struct rdac_mode_10_hdr {
-	u16	data_len;
-	u8	medium_type;
-	u8	device_params;
-	u16	reserved;
-	u16	block_desc_len;
-};
-
-struct rdac_mode_common {
-	u8	controller_serial[16];
-	u8	alt_controller_serial[16];
-	u8	rdac_mode[2];
-	u8	alt_rdac_mode[2];
-	u8	quiescence_timeout;
-	u8	rdac_options;
-};
-
-struct rdac_pg_legacy {
-	struct rdac_mode_6_hdr hdr;
-	u8	page_code;
-	u8	page_len;
-	struct rdac_mode_common common;
-#define MODE6_MAX_LUN	32
-	u8	lun_table[MODE6_MAX_LUN];
-	u8	reserved2[32];
-	u8	reserved3;
-	u8	reserved4;
-};
-
-struct rdac_pg_expanded {
-	struct rdac_mode_10_hdr hdr;
-	u8	page_code;
-	u8	subpage_code;
-	u8	page_len[2];
-	struct rdac_mode_common common;
-	u8	lun_table[256];
-	u8	reserved3;
-	u8	reserved4;
-};
-
-struct c9_inquiry {
-	u8	peripheral_info;
-	u8	page_code;	/* 0xC9 */
-	u8	reserved1;
-	u8	page_len;
-	u8	page_id[4];	/* "vace" */
-	u8	avte_cvp;
-	u8	path_prio;
-	u8	reserved2[38];
-};
-
-#define SUBSYS_ID_LEN	16
-#define SLOT_ID_LEN	2
-
-struct c4_inquiry {
-	u8	peripheral_info;
-	u8	page_code;	/* 0xC4 */
-	u8	reserved1;
-	u8	page_len;
-	u8	page_id[4];	/* "subs" */
-	u8	subsys_id[SUBSYS_ID_LEN];
-	u8	revision[4];
-	u8	slot_id[SLOT_ID_LEN];
-	u8	reserved[2];
-};
-
-struct rdac_controller {
-	u8			subsys_id[SUBSYS_ID_LEN];
-	u8			slot_id[SLOT_ID_LEN];
-	int			use_10_ms;
-	struct kref		kref;
-	struct list_head	node; /* list of all controllers */
-	spinlock_t		lock;
-	int			submitted;
-	struct list_head	cmd_list; /* list of commands to be submitted */
-	union			{
-		struct rdac_pg_legacy legacy;
-		struct rdac_pg_expanded expanded;
-	} mode_select;
-};
-struct c8_inquiry {
-	u8	peripheral_info;
-	u8	page_code; /* 0xC8 */
-	u8	reserved1;
-	u8	page_len;
-	u8	page_id[4]; /* "edid" */
-	u8	reserved2[3];
-	u8	vol_uniq_id_len;
-	u8	vol_uniq_id[16];
-	u8	vol_user_label_len;
-	u8	vol_user_label[60];
-	u8	array_uniq_id_len;
-	u8	array_unique_id[16];
-	u8	array_user_label_len;
-	u8	array_user_label[60];
-	u8	lun[8];
-};
-
-struct c2_inquiry {
-	u8	peripheral_info;
-	u8	page_code;	/* 0xC2 */
-	u8	reserved1;
-	u8	page_len;
-	u8	page_id[4];	/* "swr4" */
-	u8	sw_version[3];
-	u8	sw_date[3];
-	u8	features_enabled;
-	u8	max_lun_supported;
-	u8	partitions[239]; /* Total allocation length should be 0xFF */
-};
-
-struct rdac_handler {
-	struct list_head	entry; /* list waiting to submit MODE SELECT */
-	unsigned		timeout;
-	struct rdac_controller	*ctlr;
-#define UNINITIALIZED_LUN	(1 << 8)
-	unsigned		lun;
-	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
-	struct dm_path		*path;
-	struct work_struct	work;
-#define	SEND_C2_INQUIRY		1
-#define	SEND_C4_INQUIRY		2
-#define	SEND_C8_INQUIRY		3
-#define	SEND_C9_INQUIRY		4
-#define	SEND_MODE_SELECT	5
-	int			cmd_to_send;
-	union			{
-		struct c2_inquiry c2;
-		struct c4_inquiry c4;
-		struct c8_inquiry c8;
-		struct c9_inquiry c9;
-	} inq;
-};
-
-static LIST_HEAD(ctlr_list);
-static DEFINE_SPINLOCK(list_lock);
-static struct workqueue_struct *rdac_wkqd;
-
-static inline int had_failures(struct request *req, int error)
-{
-	return (error || host_byte(req->errors) != DID_OK ||
-			msg_byte(req->errors) != COMMAND_COMPLETE);
-}
-
-static void rdac_resubmit_all(struct rdac_handler *h)
-{
-	struct rdac_controller *ctlr = h->ctlr;
-	struct rdac_handler *tmp, *h1;
-
-	spin_lock(&ctlr->lock);
-	list_for_each_entry_safe(h1, tmp, &ctlr->cmd_list, entry) {
-		h1->cmd_to_send = SEND_C9_INQUIRY;
-		queue_work(rdac_wkqd, &h1->work);
-		list_del(&h1->entry);
-	}
-	ctlr->submitted = 0;
-	spin_unlock(&ctlr->lock);
-}
-
-static void mode_select_endio(struct request *req, int error)
-{
-	struct rdac_handler *h = req->end_io_data;
-	struct scsi_sense_hdr sense_hdr;
-	int sense = 0, fail = 0;
-
-	if (had_failures(req, error)) {
-		fail = 1;
-		goto failed;
-	}
-
-	if (status_byte(req->errors) == CHECK_CONDITION) {
-		scsi_normalize_sense(req->sense, SCSI_SENSE_BUFFERSIZE,
-				&sense_hdr);
-		sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
-				sense_hdr.ascq;
-		/* If it is retryable failure, submit the c9 inquiry again */
-		if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
-		    sense == 0x62900) {
-			/* 0x59136    - Command lock contention
-			 * 0x[6b]8b02 - Quiesense in progress or achieved
-			 * 0x62900    - Power On, Reset, or Bus Device Reset
-			 */
-			h->cmd_to_send = SEND_C9_INQUIRY;
-			queue_work(rdac_wkqd, &h->work);
-			goto done;
-		}
-		if (sense)
-			DMINFO("MODE_SELECT failed on %s with sense 0x%x",
-						h->path->dev->name, sense);
- 	}
-failed:
-	if (fail || sense)
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-	else
-		dm_pg_init_complete(h->path, 0);
-
-done:
-	rdac_resubmit_all(h);
-	__blk_put_request(req->q, req);
-}
-
-static struct request *get_rdac_req(struct rdac_handler *h,
-			void *buffer, unsigned buflen, int rw)
-{
-	struct request *rq;
-	struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
-
-	rq = blk_get_request(q, rw, GFP_KERNEL);
-
-	if (!rq) {
-		DMINFO("get_rdac_req: blk_get_request failed");
-		return NULL;
-	}
-
-	if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
-		blk_put_request(rq);
-		DMINFO("get_rdac_req: blk_rq_map_kern failed");
-		return NULL;
-	}
-
-	rq->sense = h->sense;
-	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-	rq->sense_len = 0;
-
-	rq->end_io_data = h;
-	rq->timeout = h->timeout;
-	rq->cmd_type = REQ_TYPE_BLOCK_PC;
-	rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
-	return rq;
-}
-
-static struct request *rdac_failover_get(struct rdac_handler *h)
-{
-	struct request *rq;
-	struct rdac_mode_common *common;
-	unsigned data_size;
-
-	if (h->ctlr->use_10_ms) {
-		struct rdac_pg_expanded *rdac_pg;
-
-		data_size = sizeof(struct rdac_pg_expanded);
-		rdac_pg = &h->ctlr->mode_select.expanded;
-		memset(rdac_pg, 0, data_size);
-		common = &rdac_pg->common;
-		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
-		rdac_pg->subpage_code = 0x1;
-		rdac_pg->page_len[0] = 0x01;
-		rdac_pg->page_len[1] = 0x28;
-		rdac_pg->lun_table[h->lun] = 0x81;
-	} else {
-		struct rdac_pg_legacy *rdac_pg;
-
-		data_size = sizeof(struct rdac_pg_legacy);
-		rdac_pg = &h->ctlr->mode_select.legacy;
-		memset(rdac_pg, 0, data_size);
-		common = &rdac_pg->common;
-		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
-		rdac_pg->page_len = 0x68;
-		rdac_pg->lun_table[h->lun] = 0x81;
-	}
-	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
-	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
-	common->rdac_options = RDAC_FORCED_QUIESENCE;
-
-	/* get request for block layer packet command */
-	rq = get_rdac_req(h, &h->ctlr->mode_select, data_size, WRITE);
-	if (!rq) {
-		DMERR("rdac_failover_get: no rq");
-		return NULL;
-	}
-
-	/* Prepare the command. */
-	if (h->ctlr->use_10_ms) {
-		rq->cmd[0] = MODE_SELECT_10;
-		rq->cmd[7] = data_size >> 8;
-		rq->cmd[8] = data_size & 0xff;
-	} else {
-		rq->cmd[0] = MODE_SELECT;
-		rq->cmd[4] = data_size;
-	}
-	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
-
-	return rq;
-}
-
-/* Acquires h->ctlr->lock */
-static void submit_mode_select(struct rdac_handler *h)
-{
-	struct request *rq;
-	struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
-
-	spin_lock(&h->ctlr->lock);
-	if (h->ctlr->submitted) {
-		list_add(&h->entry, &h->ctlr->cmd_list);
-		goto drop_lock;
-	}
-
-	if (!q) {
-		DMINFO("submit_mode_select: no queue");
-		goto fail_path;
-	}
-
-	rq = rdac_failover_get(h);
-	if (!rq) {
-		DMERR("submit_mode_select: no rq");
-		goto fail_path;
-	}
-
-	DMINFO("queueing MODE_SELECT command on %s", h->path->dev->name);
-
-	blk_execute_rq_nowait(q, NULL, rq, 1, mode_select_endio);
-	h->ctlr->submitted = 1;
-	goto drop_lock;
-fail_path:
-	dm_pg_init_complete(h->path, MP_FAIL_PATH);
-drop_lock:
-	spin_unlock(&h->ctlr->lock);
-}
-
-static void release_ctlr(struct kref *kref)
-{
-	struct rdac_controller *ctlr;
-	ctlr = container_of(kref, struct rdac_controller, kref);
-
-	spin_lock(&list_lock);
-	list_del(&ctlr->node);
-	spin_unlock(&list_lock);
-	kfree(ctlr);
-}
-
-static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id)
-{
-	struct rdac_controller *ctlr, *tmp;
-
-	spin_lock(&list_lock);
-
-	list_for_each_entry(tmp, &ctlr_list, node) {
-		if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
-			  (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
-			kref_get(&tmp->kref);
-			spin_unlock(&list_lock);
-			return tmp;
-		}
-	}
-	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
-	if (!ctlr)
-		goto done;
-
-	/* initialize fields of controller */
-	memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
-	memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
-	kref_init(&ctlr->kref);
-	spin_lock_init(&ctlr->lock);
-	ctlr->submitted = 0;
-	ctlr->use_10_ms = -1;
-	INIT_LIST_HEAD(&ctlr->cmd_list);
-	list_add(&ctlr->node, &ctlr_list);
-done:
-	spin_unlock(&list_lock);
-	return ctlr;
-}
-
-static void c4_endio(struct request *req, int error)
-{
-	struct rdac_handler *h = req->end_io_data;
-	struct c4_inquiry *sp;
-
-	if (had_failures(req, error)) {
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-		goto done;
-	}
-
-	sp = &h->inq.c4;
-
-	h->ctlr = get_controller(sp->subsys_id, sp->slot_id);
-
-	if (h->ctlr) {
-		h->cmd_to_send = SEND_C9_INQUIRY;
-		queue_work(rdac_wkqd, &h->work);
-	} else
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-done:
-	__blk_put_request(req->q, req);
-}
-
-static void c2_endio(struct request *req, int error)
-{
-	struct rdac_handler *h = req->end_io_data;
-	struct c2_inquiry *sp;
-
-	if (had_failures(req, error)) {
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-		goto done;
-	}
-
-	sp = &h->inq.c2;
-
-	/* If more than MODE6_MAX_LUN luns are supported, use mode select 10 */
-	if (sp->max_lun_supported >= MODE6_MAX_LUN)
-		h->ctlr->use_10_ms = 1;
-	else
-		h->ctlr->use_10_ms = 0;
-
-	h->cmd_to_send = SEND_MODE_SELECT;
-	queue_work(rdac_wkqd, &h->work);
-done:
-	__blk_put_request(req->q, req);
-}
-
-static void c9_endio(struct request *req, int error)
-{
-	struct rdac_handler *h = req->end_io_data;
-	struct c9_inquiry *sp;
-
-	if (had_failures(req, error)) {
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-		goto done;
-	}
-
-	/* We need to look at the sense keys here to take clear action.
-	 * For now simple logic: If the host is in AVT mode or if controller
-	 * owns the lun, return dm_pg_init_complete(), otherwise submit
-	 * MODE SELECT.
-	 */
-	sp = &h->inq.c9;
-
-	/* If in AVT mode, return success */
-	if ((sp->avte_cvp >> 7) == 0x1) {
-		dm_pg_init_complete(h->path, 0);
-		goto done;
-	}
-
-	/* If the controller on this path owns the LUN, return success */
-	if (sp->avte_cvp & 0x1) {
-		dm_pg_init_complete(h->path, 0);
-		goto done;
-	}
-
-	if (h->ctlr) {
-		if (h->ctlr->use_10_ms == -1)
-			h->cmd_to_send = SEND_C2_INQUIRY;
-		else
-			h->cmd_to_send = SEND_MODE_SELECT;
-	} else
-		h->cmd_to_send = SEND_C4_INQUIRY;
-	queue_work(rdac_wkqd, &h->work);
-done:
-	__blk_put_request(req->q, req);
-}
-
-static void c8_endio(struct request *req, int error)
-{
-	struct rdac_handler *h = req->end_io_data;
-	struct c8_inquiry *sp;
-
-	if (had_failures(req, error)) {
-		dm_pg_init_complete(h->path, MP_FAIL_PATH);
-		goto done;
-	}
-
-	/* We need to look at the sense keys here to take clear action.
-	 * For now simple logic: Get the lun from the inquiry page.
-	 */
-	sp = &h->inq.c8;
-	h->lun = sp->lun[7]; /* currently it uses only one byte */
-	h->cmd_to_send = SEND_C9_INQUIRY;
-	queue_work(rdac_wkqd, &h->work);
-done:
-	__blk_put_request(req->q, req);
-}
-
-static void submit_inquiry(struct rdac_handler *h, int page_code,
-		unsigned int len, rq_end_io_fn endio)
-{
-	struct request *rq;
-	struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
-
-	if (!q)
-		goto fail_path;
-
-	rq = get_rdac_req(h, &h->inq, len, READ);
-	if (!rq)
-		goto fail_path;
-
-	/* Prepare the command. */
-	rq->cmd[0] = INQUIRY;
-	rq->cmd[1] = 1;
-	rq->cmd[2] = page_code;
-	rq->cmd[4] = len;
-	rq->cmd_len = COMMAND_SIZE(INQUIRY);
-	blk_execute_rq_nowait(q, NULL, rq, 1, endio);
-	return;
-
-fail_path:
-	dm_pg_init_complete(h->path, MP_FAIL_PATH);
-}
-
-static void service_wkq(struct work_struct *work)
-{
-	struct rdac_handler *h = container_of(work, struct rdac_handler, work);
-
-	switch (h->cmd_to_send) {
-	case SEND_C2_INQUIRY:
-		submit_inquiry(h, 0xC2, sizeof(struct c2_inquiry), c2_endio);
-		break;
-	case SEND_C4_INQUIRY:
-		submit_inquiry(h, 0xC4, sizeof(struct c4_inquiry), c4_endio);
-		break;
-	case SEND_C8_INQUIRY:
-		submit_inquiry(h, 0xC8, sizeof(struct c8_inquiry), c8_endio);
-		break;
-	case SEND_C9_INQUIRY:
-		submit_inquiry(h, 0xC9, sizeof(struct c9_inquiry), c9_endio);
-		break;
-	case SEND_MODE_SELECT:
-		submit_mode_select(h);
-		break;
-	default:
-		BUG();
-	}
-}
-/*
- * only support subpage2c until we confirm that this is just a matter of
- * of updating firmware or not, and RDAC (basic AVT works already) for now
- * but we can add these in in when we get time and testers
- */
-static int rdac_create(struct hw_handler *hwh, unsigned argc, char **argv)
-{
-	struct rdac_handler *h;
-	unsigned timeout;
-
-	if (argc == 0) {
-		/* No arguments: use defaults */
-		timeout = RDAC_FAILOVER_TIMEOUT;
-	} else if (argc != 1) {
-		DMWARN("incorrect number of arguments");
-		return -EINVAL;
-	} else {
-		if (sscanf(argv[1], "%u", &timeout) != 1) {
-			DMWARN("invalid timeout value");
-			return -EINVAL;
-		}
-	}
-
-	h = kzalloc(sizeof(*h), GFP_KERNEL);
-	if (!h)
-		return -ENOMEM;
-
-	hwh->context = h;
-	h->timeout = timeout;
-	h->lun = UNINITIALIZED_LUN;
-	INIT_WORK(&h->work, service_wkq);
-	DMWARN("using RDAC command with timeout %u", h->timeout);
-
-	return 0;
-}
-
-static void rdac_destroy(struct hw_handler *hwh)
-{
-	struct rdac_handler *h = hwh->context;
-
-	if (h->ctlr)
-		kref_put(&h->ctlr->kref, release_ctlr);
-	kfree(h);
-	hwh->context = NULL;
-}
-
-static unsigned rdac_error(struct hw_handler *hwh, struct bio *bio)
-{
-	/* Try default handler */
-	return dm_scsi_err_handler(hwh, bio);
-}
-
-static void rdac_pg_init(struct hw_handler *hwh, unsigned bypassed,
-			struct dm_path *path)
-{
-	struct rdac_handler *h = hwh->context;
-
-	h->path = path;
-	switch (h->lun) {
-	case UNINITIALIZED_LUN:
-		submit_inquiry(h, 0xC8, sizeof(struct c8_inquiry), c8_endio);
-		break;
-	default:
-		submit_inquiry(h, 0xC9, sizeof(struct c9_inquiry), c9_endio);
-	}
-}
-
-static struct hw_handler_type rdac_handler = {
-	.name = RDAC_DM_HWH_NAME,
-	.module = THIS_MODULE,
-	.create = rdac_create,
-	.destroy = rdac_destroy,
-	.pg_init = rdac_pg_init,
-	.error = rdac_error,
-};
-
-static int __init rdac_init(void)
-{
-	int r;
-
-	rdac_wkqd = create_singlethread_workqueue("rdac_wkqd");
-	if (!rdac_wkqd) {
-		DMERR("Failed to create workqueue rdac_wkqd.");
-		return -ENOMEM;
-	}
-
-	r = dm_register_hw_handler(&rdac_handler);
-	if (r < 0) {
-		DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r);
-		destroy_workqueue(rdac_wkqd);
-		return r;
-	}
-
-	DMINFO("%s: version %s loaded", RDAC_DM_HWH_NAME, RDAC_DM_HWH_VER);
-	return 0;
-}
-
-static void __exit rdac_exit(void)
-{
-	int r = dm_unregister_hw_handler(&rdac_handler);
-
-	destroy_workqueue(rdac_wkqd);
-	if (r < 0)
-		DMERR("%s: unregister failed %d", RDAC_DM_HWH_NAME, r);
-}
-
-module_init(rdac_init);
-module_exit(rdac_exit);
-
-MODULE_DESCRIPTION("DM Multipath LSI/Engenio RDAC support");
-MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
-MODULE_LICENSE("GPL");
-MODULE_VERSION(RDAC_DM_HWH_VER);
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index e7ee59e655d5..e8f704aa46f2 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -7,7 +7,6 @@
 
 #include "dm.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"
@@ -20,6 +19,7 @@
 #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"
@@ -61,7 +61,8 @@ struct multipath {
 
 	spinlock_t lock;
 
-	struct hw_handler hw_handler;
+	const char *hw_handler_name;
+	struct work_struct activate_path;
 	unsigned nr_priority_groups;
 	struct list_head priority_groups;
 	unsigned pg_init_required;	/* pg_init needs calling? */
@@ -106,9 +107,10 @@ typedef int (*action_fn) (struct pgpath *pgpath);
 
 static struct kmem_cache *_mpio_cache;
 
-static 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);
 
 
 /*-----------------------------------------------
@@ -178,6 +180,7 @@ 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);
@@ -193,18 +196,13 @@ 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);
 }
@@ -216,12 +214,10 @@ 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 {
@@ -409,7 +405,6 @@ 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;
@@ -439,7 +434,7 @@ 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);
@@ -652,8 +647,6 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 
 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;
 
@@ -661,30 +654,18 @@ 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";
 		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;
 	consume(as, hw_argc - 1);
 
 	return 0;
@@ -808,6 +789,7 @@ 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);
 }
@@ -1025,52 +1007,85 @@ static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
 	return limit_reached;
 }
 
-/*
- * pg_init must call this when it has completed its initialisation
- */
-void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
+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;
 
-	/*
-	 * If requested, retry pg_init until maximum number of retries exceeded.
-	 * If retry not requested and PG already bypassed, always fail the path.
-	 */
-	if (err_flags & MP_RETRY) {
-		if (pg_init_limit_reached(m, pgpath))
-			err_flags |= MP_FAIL_PATH;
-	} else 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 & ~MP_RETRY) {
+	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 = &m->current_pgpath->path;
+
+	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 dm_mpath_io *mpio)
 {
-	struct hw_handler *hwh = &m->hw_handler;
-	unsigned err_flags = MP_FAIL_PATH;	/* Default behavior */
 	unsigned long flags;
 
 	if (!error)
@@ -1097,19 +1112,8 @@ 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);
@@ -1194,7 +1198,6 @@ 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;
@@ -1214,12 +1217,10 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 			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);
 
@@ -1422,6 +1423,21 @@ static int __init dm_multipath_init(void)
 		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;
+	}
+
 	DMINFO("version %u.%u.%u loaded",
 	       multipath_target.version[0], multipath_target.version[1],
 	       multipath_target.version[2]);
@@ -1433,6 +1449,7 @@ static void __exit dm_multipath_exit(void)
 {
 	int r;
 
+	destroy_workqueue(kmpath_handlerd);
 	destroy_workqueue(kmultipathd);
 
 	r = dm_unregister_target(&multipath_target);
@@ -1441,8 +1458,6 @@ static void __exit dm_multipath_exit(void)
 	kmem_cache_destroy(_mpio_cache);
 }
 
-EXPORT_SYMBOL_GPL(dm_pg_init_complete);
-
 module_init(dm_multipath_init);
 module_exit(dm_multipath_exit);
 
diff --git a/drivers/md/dm-mpath.h b/drivers/md/dm-mpath.h
index b9cdcbb3ed59..c198b856a452 100644
--- a/drivers/md/dm-mpath.h
+++ b/drivers/md/dm-mpath.h
@@ -16,7 +16,6 @@ struct dm_path {
 	unsigned is_active;	/* Read-only */
 
 	void *pscontext;	/* For path-selector use */
-	void *hwhcontext;	/* For hw-handler use */
 };
 
 /* Callback for hwh_pg_init_fn to use when complete */
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 8c7e2b778ef1..d23027a2f2f0 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -847,6 +847,14 @@ zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
 	/* mark unit unusable as long as sysfs registration is not complete */
 	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 
+	spin_lock_init(&unit->latencies.lock);
+	unit->latencies.write.channel.min = 0xFFFFFFFF;
+	unit->latencies.write.fabric.min = 0xFFFFFFFF;
+	unit->latencies.read.channel.min = 0xFFFFFFFF;
+	unit->latencies.read.fabric.min = 0xFFFFFFFF;
+	unit->latencies.cmd.channel.min = 0xFFFFFFFF;
+	unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
+
 	if (device_register(&unit->sysfs_device)) {
 		kfree(unit);
 		return NULL;
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index bda8c77b22da..306fcd0cae31 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -708,6 +708,24 @@ struct zfcp_erp_action {
 	struct timer_list timer;
 };
 
+struct fsf_latency_record {
+	u32 min;
+	u32 max;
+	u64 sum;
+};
+
+struct latency_cont {
+	struct fsf_latency_record channel;
+	struct fsf_latency_record fabric;
+	u64 counter;
+};
+
+struct zfcp_latencies {
+	struct latency_cont read;
+	struct latency_cont write;
+	struct latency_cont cmd;
+	spinlock_t lock;
+};
 
 struct zfcp_adapter {
 	struct list_head	list;              /* list of adapters */
@@ -723,6 +741,7 @@ struct zfcp_adapter {
 	u32			adapter_features;  /* FCP channel features */
 	u32			connection_features; /* host connection features */
         u32			hardware_version;  /* of FCP channel */
+	u16			timer_ticks;       /* time int for a tick */
 	struct Scsi_Host	*scsi_host;	   /* Pointer to mid-layer */
 	struct list_head	port_list_head;	   /* remote port list */
 	struct list_head        port_remove_lh;    /* head of ports to be
@@ -822,6 +841,7 @@ struct zfcp_unit {
         struct scsi_device     *device;        /* scsi device struct pointer */
 	struct zfcp_erp_action erp_action;     /* pending error recovery */
         atomic_t               erp_counter;
+	struct zfcp_latencies	latencies;
 };
 
 /* FSF request */
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index b2ea4ea051f5..1e7136483c1b 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -2005,6 +2005,7 @@ zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *fsf_req, int xchg_ok)
 		fc_host_supported_classes(shost) =
 				FC_COS_CLASS2 | FC_COS_CLASS3;
 		adapter->hydra_version = bottom->adapter_type;
+		adapter->timer_ticks = bottom->timer_interval;
 		if (fc_host_permanent_port_name(shost) == -1)
 			fc_host_permanent_port_name(shost) =
 				fc_host_port_name(shost);
@@ -3649,6 +3650,46 @@ zfcp_fsf_send_fcp_command_task_management(struct zfcp_adapter *adapter,
 	return fsf_req;
 }
 
+static void zfcp_fsf_update_lat(struct fsf_latency_record *lat_rec, u32 lat)
+{
+	lat_rec->sum += lat;
+	if (lat_rec->min > lat)
+		lat_rec->min = lat;
+	if (lat_rec->max < lat)
+		lat_rec->max = lat;
+}
+
+static void zfcp_fsf_req_latency(struct zfcp_fsf_req *fsf_req)
+{
+	struct fsf_qual_latency_info *lat_inf;
+	struct latency_cont *lat;
+	struct zfcp_unit *unit;
+	unsigned long flags;
+
+	lat_inf = &fsf_req->qtcb->prefix.prot_status_qual.latency_info;
+	unit = fsf_req->unit;
+
+	switch (fsf_req->qtcb->bottom.io.data_direction) {
+	case FSF_DATADIR_READ:
+		lat = &unit->latencies.read;
+		break;
+	case FSF_DATADIR_WRITE:
+		lat = &unit->latencies.write;
+		break;
+	case FSF_DATADIR_CMND:
+		lat = &unit->latencies.cmd;
+		break;
+	default:
+		return;
+	}
+
+	spin_lock_irqsave(&unit->latencies.lock, flags);
+	zfcp_fsf_update_lat(&lat->channel, lat_inf->channel_lat);
+	zfcp_fsf_update_lat(&lat->fabric, lat_inf->fabric_lat);
+	lat->counter++;
+	spin_unlock_irqrestore(&unit->latencies.lock, flags);
+}
+
 /*
  * function:    zfcp_fsf_send_fcp_command_handler
  *
@@ -3922,6 +3963,9 @@ zfcp_fsf_send_fcp_command_task_handler(struct zfcp_fsf_req *fsf_req)
 			      fcp_rsp_iu->fcp_sns_len);
 	}
 
+	if (fsf_req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA)
+		zfcp_fsf_req_latency(fsf_req);
+
 	/* check FCP_RSP_INFO */
 	if (unlikely(fcp_rsp_iu->validity.bits.fcp_rsp_len_valid)) {
 		ZFCP_LOG_DEBUG("rsp_len is valid\n");
diff --git a/drivers/s390/scsi/zfcp_fsf.h b/drivers/s390/scsi/zfcp_fsf.h
index 099970b27001..8b1a7d9c840f 100644
--- a/drivers/s390/scsi/zfcp_fsf.h
+++ b/drivers/s390/scsi/zfcp_fsf.h
@@ -323,11 +323,18 @@ struct fsf_link_down_info {
 	u8 vendor_specific_code;
 } __attribute__ ((packed));
 
+struct fsf_qual_latency_info {
+	u32 channel_lat;
+	u32 fabric_lat;
+	u8 res1[8];
+} __attribute__ ((packed));
+
 union fsf_prot_status_qual {
 	u64 doubleword[FSF_PROT_STATUS_QUAL_SIZE / sizeof(u64)];
 	struct fsf_qual_version_error   version_error;
 	struct fsf_qual_sequence_error  sequence_error;
 	struct fsf_link_down_info link_down_info;
+	struct fsf_qual_latency_info latency_info;
 } __attribute__ ((packed));
 
 struct fsf_qtcb_prefix {
@@ -437,7 +444,9 @@ struct fsf_qtcb_bottom_config {
 	u32 fc_link_speed;
 	u32 adapter_type;
 	u32 peer_d_id;
-	u8 res2[12];
+	u8 res1[2];
+	u16 timer_interval;
+	u8 res2[8];
 	u32 s_id;
 	struct fsf_nport_serv_param nport_serv_param;
 	u8 reserved_nport_serv_param[16];
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 01687559dc06..4b0c85acb0f0 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -778,6 +778,68 @@ struct fc_function_template zfcp_transport_functions = {
 	.disable_target_scan = 1,
 };
 
+#define ZFCP_DEFINE_LATENCY_ATTR(_name) 				\
+static ssize_t								\
+zfcp_sysfs_unit_##_name##_latency_show(struct device *dev,		\
+				       struct device_attribute *attr,	\
+				       char *buf) {			\
+	struct scsi_device *sdev = to_scsi_device(dev);			\
+	struct zfcp_unit *unit = sdev->hostdata;			\
+	struct zfcp_latencies *lat = &unit->latencies;			\
+	struct zfcp_adapter *adapter = unit->port->adapter;		\
+	unsigned long flags;						\
+	unsigned long long fsum, fmin, fmax, csum, cmin, cmax, cc;	\
+									\
+	spin_lock_irqsave(&lat->lock, flags);				\
+	fsum = lat->_name.fabric.sum * adapter->timer_ticks;		\
+	fmin = lat->_name.fabric.min * adapter->timer_ticks;		\
+	fmax = lat->_name.fabric.max * adapter->timer_ticks;		\
+	csum = lat->_name.channel.sum * adapter->timer_ticks;		\
+	cmin = lat->_name.channel.min * adapter->timer_ticks;		\
+	cmax = lat->_name.channel.max * adapter->timer_ticks;		\
+	cc  = lat->_name.counter;					\
+	spin_unlock_irqrestore(&lat->lock, flags);			\
+									\
+	do_div(fsum, 1000);						\
+	do_div(fmin, 1000);						\
+	do_div(fmax, 1000);						\
+	do_div(csum, 1000);						\
+	do_div(cmin, 1000);						\
+	do_div(cmax, 1000);						\
+									\
+	return sprintf(buf, "%llu %llu %llu %llu %llu %llu %llu\n",	\
+		       fmin, fmax, fsum, cmin, cmax, csum, cc); 	\
+}									\
+static ssize_t								\
+zfcp_sysfs_unit_##_name##_latency_store(struct device *dev,		\
+					struct device_attribute *attr,	\
+					const char *buf, size_t count)	\
+{									\
+	struct scsi_device *sdev = to_scsi_device(dev);			\
+	struct zfcp_unit *unit = sdev->hostdata;			\
+	struct zfcp_latencies *lat = &unit->latencies;			\
+	unsigned long flags;						\
+									\
+	spin_lock_irqsave(&lat->lock, flags);				\
+	lat->_name.fabric.sum = 0;					\
+	lat->_name.fabric.min = 0xFFFFFFFF;				\
+	lat->_name.fabric.max = 0;					\
+	lat->_name.channel.sum = 0;					\
+	lat->_name.channel.min = 0xFFFFFFFF;				\
+	lat->_name.channel.max = 0;					\
+	lat->_name.counter = 0;						\
+	spin_unlock_irqrestore(&lat->lock, flags);			\
+									\
+	return (ssize_t) count;						\
+}									\
+static DEVICE_ATTR(_name##_latency, S_IWUSR | S_IRUGO,			\
+		   zfcp_sysfs_unit_##_name##_latency_show,		\
+		   zfcp_sysfs_unit_##_name##_latency_store);
+
+ZFCP_DEFINE_LATENCY_ATTR(read);
+ZFCP_DEFINE_LATENCY_ATTR(write);
+ZFCP_DEFINE_LATENCY_ATTR(cmd);
+
 /**
  * ZFCP_DEFINE_SCSI_ATTR
  * @_name:   name of show attribute
@@ -808,6 +870,9 @@ static struct device_attribute *zfcp_sysfs_sdev_attrs[] = {
 	&dev_attr_fcp_lun,
 	&dev_attr_wwpn,
 	&dev_attr_hba_id,
+	&dev_attr_read_latency,
+	&dev_attr_write_latency,
+	&dev_attr_cmd_latency,
 	NULL
 };
 
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 81ccbd7f9e34..7886ec6e5f87 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -1771,4 +1771,6 @@ endif # SCSI_LOWLEVEL
 
 source "drivers/scsi/pcmcia/Kconfig"
 
+source "drivers/scsi/device_handler/Kconfig"
+
 endmenu
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 6c775e350c98..aa8272e188ea 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SCSI_ISCSI_ATTRS)	+= scsi_transport_iscsi.o
 obj-$(CONFIG_SCSI_SAS_ATTRS)	+= scsi_transport_sas.o
 obj-$(CONFIG_SCSI_SAS_LIBSAS)	+= libsas/
 obj-$(CONFIG_SCSI_SRP_ATTRS)	+= scsi_transport_srp.o
+obj-$(CONFIG_SCSI_DH)		+= device_handler/
 
 obj-$(CONFIG_ISCSI_TCP) 	+= libiscsi.o	iscsi_tcp.o
 obj-$(CONFIG_INFINIBAND_ISER) 	+= libiscsi.o
diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index 1f7c83607f84..5797b2c42f08 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -862,7 +862,7 @@ static ssize_t aac_show_bios_version(struct device *device,
 	return len;
 }
 
-ssize_t aac_show_serial_number(struct device *device,
+static ssize_t aac_show_serial_number(struct device *device,
 			       struct device_attribute *attr, char *buf)
 {
 	struct aac_dev *dev = (struct aac_dev*)class_to_shost(device)->hostdata;
diff --git a/drivers/scsi/device_handler/Kconfig b/drivers/scsi/device_handler/Kconfig
new file mode 100644
index 000000000000..2adc0f666b68
--- /dev/null
+++ b/drivers/scsi/device_handler/Kconfig
@@ -0,0 +1,32 @@
+#
+# SCSI Device Handler configuration
+#
+
+menuconfig SCSI_DH
+	tristate "SCSI Device Handlers"
+	depends on SCSI
+	default n
+	help
+	  SCSI Device Handlers provide device specific support for
+	  devices utilized in multipath configurations. Say Y here to
+	  select support for specific hardware.
+
+config SCSI_DH_RDAC
+	tristate "LSI RDAC Device Handler"
+	depends on SCSI_DH
+	help
+	If you have a LSI RDAC select y. Otherwise, say N.
+
+config SCSI_DH_HP_SW
+	tristate "HP/COMPAQ MSA Device Handler"
+	depends on SCSI_DH
+	help
+	If you have a HP/COMPAQ MSA device that requires START_STOP to
+	be sent to start it and cannot upgrade the firmware then select y.
+	Otherwise, say N.
+
+config SCSI_DH_EMC
+	tristate "EMC CLARiiON Device Handler"
+	depends on SCSI_DH
+	help
+	If you have a EMC CLARiiON select y. Otherwise, say N.
diff --git a/drivers/scsi/device_handler/Makefile b/drivers/scsi/device_handler/Makefile
new file mode 100644
index 000000000000..35272e93b1c8
--- /dev/null
+++ b/drivers/scsi/device_handler/Makefile
@@ -0,0 +1,7 @@
+#
+# SCSI Device Handler
+#
+obj-$(CONFIG_SCSI_DH)		+= scsi_dh.o
+obj-$(CONFIG_SCSI_DH_RDAC)	+= scsi_dh_rdac.o
+obj-$(CONFIG_SCSI_DH_HP_SW)	+= scsi_dh_hp_sw.o
+obj-$(CONFIG_SCSI_DH_EMC)	+= scsi_dh_emc.o
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
new file mode 100644
index 000000000000..ab6c21cd9689
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -0,0 +1,162 @@
+/*
+ * SCSI device handler infrastruture.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2007
+ *      Authors:
+ *               Chandra Seetharaman <sekharan@us.ibm.com>
+ *               Mike Anderson <andmike@linux.vnet.ibm.com>
+ */
+
+#include <scsi/scsi_dh.h>
+#include "../scsi_priv.h"
+
+static DEFINE_SPINLOCK(list_lock);
+static LIST_HEAD(scsi_dh_list);
+
+static struct scsi_device_handler *get_device_handler(const char *name)
+{
+	struct scsi_device_handler *tmp, *found = NULL;
+
+	spin_lock(&list_lock);
+	list_for_each_entry(tmp, &scsi_dh_list, list) {
+		if (!strcmp(tmp->name, name)) {
+			found = tmp;
+			break;
+		}
+	}
+	spin_unlock(&list_lock);
+	return found;
+}
+
+static int scsi_dh_notifier_add(struct device *dev, void *data)
+{
+	struct scsi_device_handler *scsi_dh = data;
+
+	scsi_dh->nb.notifier_call(&scsi_dh->nb, BUS_NOTIFY_ADD_DEVICE, dev);
+	return 0;
+}
+
+/*
+ * scsi_register_device_handler - register a device handler personality
+ *      module.
+ * @scsi_dh - device handler to be registered.
+ *
+ * Returns 0 on success, -EBUSY if handler already registered.
+ */
+int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
+{
+	int ret = -EBUSY;
+	struct scsi_device_handler *tmp;
+
+	tmp = get_device_handler(scsi_dh->name);
+	if (tmp)
+		goto done;
+
+	ret = bus_register_notifier(&scsi_bus_type, &scsi_dh->nb);
+
+	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
+	spin_lock(&list_lock);
+	list_add(&scsi_dh->list, &scsi_dh_list);
+	spin_unlock(&list_lock);
+
+done:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scsi_register_device_handler);
+
+static int scsi_dh_notifier_remove(struct device *dev, void *data)
+{
+	struct scsi_device_handler *scsi_dh = data;
+
+	scsi_dh->nb.notifier_call(&scsi_dh->nb, BUS_NOTIFY_DEL_DEVICE, dev);
+	return 0;
+}
+
+/*
+ * scsi_unregister_device_handler - register a device handler personality
+ *      module.
+ * @scsi_dh - device handler to be unregistered.
+ *
+ * Returns 0 on success, -ENODEV if handler not registered.
+ */
+int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
+{
+	int ret = -ENODEV;
+	struct scsi_device_handler *tmp;
+
+	tmp = get_device_handler(scsi_dh->name);
+	if (!tmp)
+		goto done;
+
+	ret = bus_unregister_notifier(&scsi_bus_type, &scsi_dh->nb);
+
+	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
+					scsi_dh_notifier_remove);
+	spin_lock(&list_lock);
+	list_del(&scsi_dh->list);
+	spin_unlock(&list_lock);
+
+done:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
+
+/*
+ * scsi_dh_activate - activate the path associated with the scsi_device
+ *      corresponding to the given request queue.
+ * @q - Request queue that is associated with the scsi_device to be
+ *      activated.
+ */
+int scsi_dh_activate(struct request_queue *q)
+{
+	int err = 0;
+	unsigned long flags;
+	struct scsi_device *sdev;
+	struct scsi_device_handler *scsi_dh = NULL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (sdev && sdev->scsi_dh_data)
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+	if (!scsi_dh || !get_device(&sdev->sdev_gendev))
+		err = SCSI_DH_NOSYS;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (err)
+		return err;
+
+	if (scsi_dh->activate)
+		err = scsi_dh->activate(sdev);
+	put_device(&sdev->sdev_gendev);
+	return err;
+}
+EXPORT_SYMBOL_GPL(scsi_dh_activate);
+
+/*
+ * scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for
+ *	the given name. FALSE(0) otherwise.
+ * @name - name of the device handler.
+ */
+int scsi_dh_handler_exist(const char *name)
+{
+	return (get_device_handler(name) != NULL);
+}
+EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
+
+MODULE_DESCRIPTION("SCSI device handler");
+MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
new file mode 100644
index 000000000000..ed53f14007a2
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -0,0 +1,499 @@
+/*
+ * Target driver for EMC CLARiiON AX/CX-series hardware.
+ * Based on code from Lars Marowsky-Bree <lmb@suse.de>
+ * and Ed Goggin <egoggin@emc.com>.
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006 Mike Christie
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <scsi/scsi.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+#include <scsi/scsi_device.h>
+
+#define CLARIION_NAME			"emc_clariion"
+
+#define CLARIION_TRESPASS_PAGE		0x22
+#define CLARIION_BUFFER_SIZE		0x80
+#define CLARIION_TIMEOUT		(60 * HZ)
+#define CLARIION_RETRIES		3
+#define CLARIION_UNBOUND_LU		-1
+
+static unsigned char long_trespass[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x09,			/* Page length - 2 */
+	0x81,			/* Trespass code + Honor reservation bit */
+	0xff, 0xff,		/* Trespass target */
+	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
+};
+
+static unsigned char long_trespass_hr[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x09,			/* Page length - 2 */
+	0x01,			/* Trespass code + Honor reservation bit */
+	0xff, 0xff,		/* Trespass target */
+	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
+};
+
+static unsigned char short_trespass[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x02,			/* Page length - 2 */
+	0x81,			/* Trespass code + Honor reservation bit */
+	0xff,			/* Trespass target */
+};
+
+static unsigned char short_trespass_hr[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x02,			/* Page length - 2 */
+	0x01,			/* Trespass code + Honor reservation bit */
+	0xff,			/* Trespass target */
+};
+
+struct clariion_dh_data {
+	/*
+	 * Use short trespass command (FC-series) or the long version
+	 * (default for AX/CX CLARiiON arrays).
+	 */
+	unsigned short_trespass;
+	/*
+	 * Whether or not (default) to honor SCSI reservations when
+	 * initiating a switch-over.
+	 */
+	unsigned hr;
+	/* I/O buffer for both MODE_SELECT and INQUIRY commands. */
+	char buffer[CLARIION_BUFFER_SIZE];
+	/*
+	 * SCSI sense buffer for commands -- assumes serial issuance
+	 * and completion sequence of all commands for same multipath.
+	 */
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+	/* which SP (A=0,B=1,UNBOUND=-1) is dflt SP for path's mapped dev */
+	int default_sp;
+	/* which SP (A=0,B=1,UNBOUND=-1) is active for path's mapped dev */
+	int current_sp;
+};
+
+static inline struct clariion_dh_data
+			*get_clariion_data(struct scsi_device *sdev)
+{
+	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+	BUG_ON(scsi_dh_data == NULL);
+	return ((struct clariion_dh_data *) scsi_dh_data->buf);
+}
+
+/*
+ * Parse MODE_SELECT cmd reply.
+ */
+static int trespass_endio(struct scsi_device *sdev, int result)
+{
+	int err = SCSI_DH_OK;
+	struct scsi_sense_hdr sshdr;
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	char *sense = csdev->sense;
+
+	if (status_byte(result) == CHECK_CONDITION &&
+	    scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
+		sdev_printk(KERN_ERR, sdev, "Found valid sense data 0x%2x, "
+			    "0x%2x, 0x%2x while sending CLARiiON trespass "
+			    "command.\n", sshdr.sense_key, sshdr.asc,
+			     sshdr.ascq);
+
+		if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
+		     (sshdr.ascq == 0x00)) {
+			/*
+			 * Array based copy in progress -- do not send
+			 * mode_select or copy will be aborted mid-stream.
+			 */
+			sdev_printk(KERN_INFO, sdev, "Array Based Copy in "
+				    "progress while sending CLARiiON trespass "
+				    "command.\n");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
+			    (sshdr.ascq == 0x03)) {
+			/*
+			 * LUN Not Ready - Manual Intervention Required
+			 * indicates in-progress ucode upgrade (NDU).
+			 */
+			sdev_printk(KERN_INFO, sdev, "Detected in-progress "
+				    "ucode upgrade NDU operation while sending "
+				    "CLARiiON trespass command.\n");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else
+			err = SCSI_DH_DEV_FAILED;
+	} else if (result) {
+		sdev_printk(KERN_ERR, sdev, "Error 0x%x while sending "
+			    "CLARiiON trespass command.\n", result);
+		err = SCSI_DH_IO;
+	}
+
+	return err;
+}
+
+static int parse_sp_info_reply(struct scsi_device *sdev, int result,
+		int *default_sp, int *current_sp, int *new_current_sp)
+{
+	int err = SCSI_DH_OK;
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+
+	if (result == 0) {
+		/* check for in-progress ucode upgrade (NDU) */
+		if (csdev->buffer[48] != 0) {
+			sdev_printk(KERN_NOTICE, sdev, "Detected in-progress "
+			       "ucode upgrade NDU operation while finding "
+			       "current active SP.");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else {
+			*default_sp = csdev->buffer[5];
+
+			if (csdev->buffer[4] == 2)
+				/* SP for path is current */
+				*current_sp = csdev->buffer[8];
+			else {
+				if (csdev->buffer[4] == 1)
+					/* SP for this path is NOT current */
+					if (csdev->buffer[8] == 0)
+						*current_sp = 1;
+					else
+						*current_sp = 0;
+				else
+					/* unbound LU or LUNZ */
+					*current_sp = CLARIION_UNBOUND_LU;
+			}
+			*new_current_sp =  csdev->buffer[8];
+		}
+	} else {
+		struct scsi_sense_hdr sshdr;
+
+		err = SCSI_DH_IO;
+
+		if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
+							   &sshdr))
+			sdev_printk(KERN_ERR, sdev, "Found valid sense data "
+			      "0x%2x, 0x%2x, 0x%2x while finding current "
+			      "active SP.", sshdr.sense_key, sshdr.asc,
+			      sshdr.ascq);
+		else
+			sdev_printk(KERN_ERR, sdev, "Error 0x%x finding "
+			      "current active SP.", result);
+	}
+
+	return err;
+}
+
+static int sp_info_endio(struct scsi_device *sdev, int result,
+					int mode_select_sent, int *done)
+{
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	int err_flags, default_sp, current_sp, new_current_sp;
+
+	err_flags = parse_sp_info_reply(sdev, result, &default_sp,
+					     &current_sp, &new_current_sp);
+
+	if (err_flags != SCSI_DH_OK)
+		goto done;
+
+	if (mode_select_sent) {
+		csdev->default_sp = default_sp;
+		csdev->current_sp = current_sp;
+	} else {
+		/*
+		 * Issue the actual module_selec request IFF either
+		 * (1) we do not know the identity of the current SP OR
+		 * (2) what we think we know is actually correct.
+		 */
+		if ((current_sp != CLARIION_UNBOUND_LU) &&
+		    (new_current_sp != current_sp)) {
+
+			csdev->default_sp = default_sp;
+			csdev->current_sp = current_sp;
+
+			sdev_printk(KERN_INFO, sdev, "Ignoring path group "
+			       "switch-over command for CLARiiON SP%s since "
+			       " mapped device is already initialized.",
+			       current_sp ? "B" : "A");
+			if (done)
+				*done = 1; /* as good as doing it */
+		}
+	}
+done:
+	return err_flags;
+}
+
+/*
+* Get block request for REQ_BLOCK_PC command issued to path.  Currently
+* limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
+*
+* Uses data and sense buffers in hardware handler context structure and
+* assumes serial servicing of commands, both issuance and completion.
+*/
+static struct request *get_req(struct scsi_device *sdev, int cmd)
+{
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	struct request *rq;
+	unsigned char *page22;
+	int len = 0;
+
+	rq = blk_get_request(sdev->request_queue,
+			(cmd == MODE_SELECT) ? WRITE : READ, GFP_ATOMIC);
+	if (!rq) {
+		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
+		return NULL;
+	}
+
+	memset(&rq->cmd, 0, BLK_MAX_CDB);
+	rq->cmd[0] = cmd;
+	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+	switch (cmd) {
+	case MODE_SELECT:
+		if (csdev->short_trespass) {
+			page22 = csdev->hr ? short_trespass_hr : short_trespass;
+			len = sizeof(short_trespass);
+		} else {
+			page22 = csdev->hr ? long_trespass_hr : long_trespass;
+			len = sizeof(long_trespass);
+		}
+		/*
+		 * Can't DMA from kernel BSS -- must copy selected trespass
+		 * command mode page contents to context buffer which is
+		 * allocated by kmalloc.
+		 */
+		BUG_ON((len > CLARIION_BUFFER_SIZE));
+		memcpy(csdev->buffer, page22, len);
+		rq->cmd_flags |= REQ_RW;
+		rq->cmd[1] = 0x10;
+		break;
+	case INQUIRY:
+		rq->cmd[1] = 0x1;
+		rq->cmd[2] = 0xC0;
+		len = CLARIION_BUFFER_SIZE;
+		memset(csdev->buffer, 0, CLARIION_BUFFER_SIZE);
+		break;
+	default:
+		BUG_ON(1);
+		break;
+	}
+
+	rq->cmd[4] = len;
+	rq->cmd_type = REQ_TYPE_BLOCK_PC;
+	rq->cmd_flags |= REQ_FAILFAST;
+	rq->timeout = CLARIION_TIMEOUT;
+	rq->retries = CLARIION_RETRIES;
+
+	rq->sense = csdev->sense;
+	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+	rq->sense_len = 0;
+
+	if (blk_rq_map_kern(sdev->request_queue, rq, csdev->buffer,
+							len, GFP_ATOMIC)) {
+		__blk_put_request(rq->q, rq);
+		return NULL;
+	}
+
+	return rq;
+}
+
+static int send_cmd(struct scsi_device *sdev, int cmd)
+{
+	struct request *rq = get_req(sdev, cmd);
+
+	if (!rq)
+		return SCSI_DH_RES_TEMP_UNAVAIL;
+
+	return blk_execute_rq(sdev->request_queue, NULL, rq, 1);
+}
+
+static int clariion_activate(struct scsi_device *sdev)
+{
+	int result, done = 0;
+
+	result = send_cmd(sdev, INQUIRY);
+	result = sp_info_endio(sdev, result, 0, &done);
+	if (result || done)
+		goto done;
+
+	result = send_cmd(sdev, MODE_SELECT);
+	result = trespass_endio(sdev, result);
+	if (result)
+		goto done;
+
+	result = send_cmd(sdev, INQUIRY);
+	result = sp_info_endio(sdev, result, 1, NULL);
+done:
+	return result;
+}
+
+static int clariion_check_sense(struct scsi_device *sdev,
+				struct scsi_sense_hdr *sense_hdr)
+{
+	switch (sense_hdr->sense_key) {
+	case NOT_READY:
+		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
+			/*
+			 * LUN Not Ready - Manual Intervention Required
+			 * indicates this is a passive path.
+			 *
+			 * FIXME: However, if this is seen and EVPD C0
+			 * indicates that this is due to a NDU in
+			 * progress, we should set FAIL_PATH too.
+			 * This indicates we might have to do a SCSI
+			 * inquiry in the end_io path. Ugh.
+			 *
+			 * Can return FAILED only when we want the error
+			 * recovery process to kick in.
+			 */
+			return SUCCESS;
+		break;
+	case ILLEGAL_REQUEST:
+		if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
+			/*
+			 * An array based copy is in progress. Do not
+			 * fail the path, do not bypass to another PG,
+			 * do not retry. Fail the IO immediately.
+			 * (Actually this is the same conclusion as in
+			 * the default handler, but lets make sure.)
+			 *
+			 * Can return FAILED only when we want the error
+			 * recovery process to kick in.
+			 */
+			return SUCCESS;
+		break;
+	case UNIT_ATTENTION:
+		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
+			/*
+			 * Unit Attention Code. This is the first IO
+			 * to the new path, so just retry.
+			 */
+			return NEEDS_RETRY;
+		break;
+	}
+
+	/* success just means we do not care what scsi-ml does */
+	return SUCCESS;
+}
+
+static const struct {
+	char *vendor;
+	char *model;
+} clariion_dev_list[] = {
+	{"DGC", "RAID"},
+	{"DGC", "DISK"},
+	{NULL, NULL},
+};
+
+static int clariion_bus_notify(struct notifier_block *, unsigned long, void *);
+
+static struct scsi_device_handler clariion_dh = {
+	.name		= CLARIION_NAME,
+	.module		= THIS_MODULE,
+	.nb.notifier_call = clariion_bus_notify,
+	.check_sense	= clariion_check_sense,
+	.activate	= clariion_activate,
+};
+
+/*
+ * TODO: need some interface so we can set trespass values
+ */
+static int clariion_bus_notify(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_dh_data *scsi_dh_data;
+	struct clariion_dh_data *h;
+	int i, found = 0;
+	unsigned long flags;
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		for (i = 0; clariion_dev_list[i].vendor; i++) {
+			if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
+				     strlen(clariion_dev_list[i].vendor)) &&
+			    !strncmp(sdev->model, clariion_dev_list[i].model,
+				     strlen(clariion_dev_list[i].model))) {
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			goto out;
+
+		scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+				+ sizeof(*h) , GFP_KERNEL);
+		if (!scsi_dh_data) {
+			sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
+				    CLARIION_NAME);
+			goto out;
+		}
+
+		scsi_dh_data->scsi_dh = &clariion_dh;
+		h = (struct clariion_dh_data *) scsi_dh_data->buf;
+		h->default_sp = CLARIION_UNBOUND_LU;
+		h->current_sp = CLARIION_UNBOUND_LU;
+
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		sdev->scsi_dh_data = scsi_dh_data;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+		sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", CLARIION_NAME);
+		try_module_get(THIS_MODULE);
+
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		if (sdev->scsi_dh_data == NULL ||
+				sdev->scsi_dh_data->scsi_dh != &clariion_dh)
+			goto out;
+
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		scsi_dh_data = sdev->scsi_dh_data;
+		sdev->scsi_dh_data = NULL;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+		sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n",
+			    CLARIION_NAME);
+
+		kfree(scsi_dh_data);
+		module_put(THIS_MODULE);
+	}
+
+out:
+	return 0;
+}
+
+static int __init clariion_init(void)
+{
+	int r;
+
+	r = scsi_register_device_handler(&clariion_dh);
+	if (r != 0)
+		printk(KERN_ERR "Failed to register scsi device handler.");
+	return r;
+}
+
+static void __exit clariion_exit(void)
+{
+	scsi_unregister_device_handler(&clariion_dh);
+}
+
+module_init(clariion_init);
+module_exit(clariion_exit);
+
+MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
new file mode 100644
index 000000000000..12ceab7b3662
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -0,0 +1,202 @@
+/*
+ * Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
+ * upgraded.
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006 Mike Christie
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+
+#define HP_SW_NAME	"hp_sw"
+
+#define HP_SW_TIMEOUT (60 * HZ)
+#define HP_SW_RETRIES 3
+
+struct hp_sw_dh_data {
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+	int retries;
+};
+
+static inline struct hp_sw_dh_data *get_hp_sw_data(struct scsi_device *sdev)
+{
+	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+	BUG_ON(scsi_dh_data == NULL);
+	return ((struct hp_sw_dh_data *) scsi_dh_data->buf);
+}
+
+static int hp_sw_done(struct scsi_device *sdev)
+{
+	struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
+	struct scsi_sense_hdr sshdr;
+	int rc;
+
+	sdev_printk(KERN_INFO, sdev, "hp_sw_done\n");
+
+	rc = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, &sshdr);
+	if (!rc)
+		goto done;
+	switch (sshdr.sense_key) {
+	case NOT_READY:
+		if ((sshdr.asc == 0x04) && (sshdr.ascq == 3)) {
+			rc = SCSI_DH_RETRY;
+			h->retries++;
+			break;
+		}
+		/* fall through */
+	default:
+		h->retries++;
+		rc = SCSI_DH_IMM_RETRY;
+	}
+
+done:
+	if (rc == SCSI_DH_OK || rc == SCSI_DH_IO)
+		h->retries = 0;
+	else if (h->retries > HP_SW_RETRIES) {
+		h->retries = 0;
+		rc = SCSI_DH_IO;
+	}
+	return rc;
+}
+
+static int hp_sw_activate(struct scsi_device *sdev)
+{
+	struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
+	struct request *req;
+	int ret = SCSI_DH_RES_TEMP_UNAVAIL;
+
+	req = blk_get_request(sdev->request_queue, WRITE, GFP_ATOMIC);
+	if (!req)
+		goto done;
+
+	sdev_printk(KERN_INFO, sdev, "sending START_STOP.");
+
+	req->cmd_type = REQ_TYPE_BLOCK_PC;
+	req->cmd_flags |= REQ_FAILFAST;
+	req->cmd_len = COMMAND_SIZE(START_STOP);
+	memset(req->cmd, 0, MAX_COMMAND_SIZE);
+	req->cmd[0] = START_STOP;
+	req->cmd[4] = 1;	/* Start spin cycle */
+	req->timeout = HP_SW_TIMEOUT;
+	req->sense = h->sense;
+	memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
+	req->sense_len = 0;
+
+	ret = blk_execute_rq(req->q, NULL, req, 1);
+	if (!ret) /* SUCCESS */
+		ret = hp_sw_done(sdev);
+	else
+		ret = SCSI_DH_IO;
+done:
+	return ret;
+}
+
+static const struct {
+	char *vendor;
+	char *model;
+} hp_sw_dh_data_list[] = {
+	{"COMPAQ", "MSA"},
+	{"HP", "HSV"},
+	{"DEC", "HSG80"},
+	{NULL, NULL},
+};
+
+static int hp_sw_bus_notify(struct notifier_block *, unsigned long, void *);
+
+static struct scsi_device_handler hp_sw_dh = {
+	.name		= HP_SW_NAME,
+	.module		= THIS_MODULE,
+	.nb.notifier_call = hp_sw_bus_notify,
+	.activate	= hp_sw_activate,
+};
+
+static int hp_sw_bus_notify(struct notifier_block *nb,
+			    unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_dh_data *scsi_dh_data;
+	int i, found = 0;
+	unsigned long flags;
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		for (i = 0; hp_sw_dh_data_list[i].vendor; i++) {
+			if (!strncmp(sdev->vendor, hp_sw_dh_data_list[i].vendor,
+				     strlen(hp_sw_dh_data_list[i].vendor)) &&
+			    !strncmp(sdev->model, hp_sw_dh_data_list[i].model,
+				     strlen(hp_sw_dh_data_list[i].model))) {
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			goto out;
+
+		scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+				+ sizeof(struct hp_sw_dh_data) , GFP_KERNEL);
+		if (!scsi_dh_data) {
+			sdev_printk(KERN_ERR, sdev, "Attach Failed %s.\n",
+				    HP_SW_NAME);
+			goto out;
+		}
+
+		scsi_dh_data->scsi_dh = &hp_sw_dh;
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		sdev->scsi_dh_data = scsi_dh_data;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+		try_module_get(THIS_MODULE);
+
+		sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", HP_SW_NAME);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		if (sdev->scsi_dh_data == NULL ||
+				sdev->scsi_dh_data->scsi_dh != &hp_sw_dh)
+			goto out;
+
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		scsi_dh_data = sdev->scsi_dh_data;
+		sdev->scsi_dh_data = NULL;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+		module_put(THIS_MODULE);
+
+		sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n", HP_SW_NAME);
+
+		kfree(scsi_dh_data);
+	}
+
+out:
+	return 0;
+}
+
+static int __init hp_sw_init(void)
+{
+	return scsi_register_device_handler(&hp_sw_dh);
+}
+
+static void __exit hp_sw_exit(void)
+{
+	scsi_unregister_device_handler(&hp_sw_dh);
+}
+
+module_init(hp_sw_init);
+module_exit(hp_sw_exit);
+
+MODULE_DESCRIPTION("HP MSA 1000");
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu");
+MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
new file mode 100644
index 000000000000..6fff077a888d
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -0,0 +1,691 @@
+/*
+ * Engenio/LSI RDAC SCSI Device Handler
+ *
+ * Copyright (C) 2005 Mike Christie. All rights reserved.
+ * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+#include <scsi/scsi.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+
+#define RDAC_NAME "rdac"
+
+/*
+ * LSI mode page stuff
+ *
+ * These struct definitions and the forming of the
+ * mode page were taken from the LSI RDAC 2.4 GPL'd
+ * driver, and then converted to Linux conventions.
+ */
+#define RDAC_QUIESCENCE_TIME 20;
+/*
+ * Page Codes
+ */
+#define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
+
+/*
+ * Controller modes definitions
+ */
+#define RDAC_MODE_TRANSFER_SPECIFIED_LUNS	0x02
+
+/*
+ * RDAC Options field
+ */
+#define RDAC_FORCED_QUIESENCE 0x02
+
+#define RDAC_TIMEOUT	(60 * HZ)
+#define RDAC_RETRIES	3
+
+struct rdac_mode_6_hdr {
+	u8	data_len;
+	u8	medium_type;
+	u8	device_params;
+	u8	block_desc_len;
+};
+
+struct rdac_mode_10_hdr {
+	u16	data_len;
+	u8	medium_type;
+	u8	device_params;
+	u16	reserved;
+	u16	block_desc_len;
+};
+
+struct rdac_mode_common {
+	u8	controller_serial[16];
+	u8	alt_controller_serial[16];
+	u8	rdac_mode[2];
+	u8	alt_rdac_mode[2];
+	u8	quiescence_timeout;
+	u8	rdac_options;
+};
+
+struct rdac_pg_legacy {
+	struct rdac_mode_6_hdr hdr;
+	u8	page_code;
+	u8	page_len;
+	struct rdac_mode_common common;
+#define MODE6_MAX_LUN	32
+	u8	lun_table[MODE6_MAX_LUN];
+	u8	reserved2[32];
+	u8	reserved3;
+	u8	reserved4;
+};
+
+struct rdac_pg_expanded {
+	struct rdac_mode_10_hdr hdr;
+	u8	page_code;
+	u8	subpage_code;
+	u8	page_len[2];
+	struct rdac_mode_common common;
+	u8	lun_table[256];
+	u8	reserved3;
+	u8	reserved4;
+};
+
+struct c9_inquiry {
+	u8	peripheral_info;
+	u8	page_code;	/* 0xC9 */
+	u8	reserved1;
+	u8	page_len;
+	u8	page_id[4];	/* "vace" */
+	u8	avte_cvp;
+	u8	path_prio;
+	u8	reserved2[38];
+};
+
+#define SUBSYS_ID_LEN	16
+#define SLOT_ID_LEN	2
+
+struct c4_inquiry {
+	u8	peripheral_info;
+	u8	page_code;	/* 0xC4 */
+	u8	reserved1;
+	u8	page_len;
+	u8	page_id[4];	/* "subs" */
+	u8	subsys_id[SUBSYS_ID_LEN];
+	u8	revision[4];
+	u8	slot_id[SLOT_ID_LEN];
+	u8	reserved[2];
+};
+
+struct rdac_controller {
+	u8			subsys_id[SUBSYS_ID_LEN];
+	u8			slot_id[SLOT_ID_LEN];
+	int			use_ms10;
+	struct kref		kref;
+	struct list_head	node; /* list of all controllers */
+	union			{
+		struct rdac_pg_legacy legacy;
+		struct rdac_pg_expanded expanded;
+	} mode_select;
+};
+struct c8_inquiry {
+	u8	peripheral_info;
+	u8	page_code; /* 0xC8 */
+	u8	reserved1;
+	u8	page_len;
+	u8	page_id[4]; /* "edid" */
+	u8	reserved2[3];
+	u8	vol_uniq_id_len;
+	u8	vol_uniq_id[16];
+	u8	vol_user_label_len;
+	u8	vol_user_label[60];
+	u8	array_uniq_id_len;
+	u8	array_unique_id[16];
+	u8	array_user_label_len;
+	u8	array_user_label[60];
+	u8	lun[8];
+};
+
+struct c2_inquiry {
+	u8	peripheral_info;
+	u8	page_code;	/* 0xC2 */
+	u8	reserved1;
+	u8	page_len;
+	u8	page_id[4];	/* "swr4" */
+	u8	sw_version[3];
+	u8	sw_date[3];
+	u8	features_enabled;
+	u8	max_lun_supported;
+	u8	partitions[239]; /* Total allocation length should be 0xFF */
+};
+
+struct rdac_dh_data {
+	struct rdac_controller	*ctlr;
+#define UNINITIALIZED_LUN	(1 << 8)
+	unsigned		lun;
+#define RDAC_STATE_ACTIVE	0
+#define RDAC_STATE_PASSIVE	1
+	unsigned char		state;
+	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
+	union			{
+		struct c2_inquiry c2;
+		struct c4_inquiry c4;
+		struct c8_inquiry c8;
+		struct c9_inquiry c9;
+	} inq;
+};
+
+static LIST_HEAD(ctlr_list);
+static DEFINE_SPINLOCK(list_lock);
+
+static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
+{
+	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+	BUG_ON(scsi_dh_data == NULL);
+	return ((struct rdac_dh_data *) scsi_dh_data->buf);
+}
+
+static struct request *get_rdac_req(struct scsi_device *sdev,
+			void *buffer, unsigned buflen, int rw)
+{
+	struct request *rq;
+	struct request_queue *q = sdev->request_queue;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	rq = blk_get_request(q, rw, GFP_KERNEL);
+
+	if (!rq) {
+		sdev_printk(KERN_INFO, sdev,
+				"get_rdac_req: blk_get_request failed.\n");
+		return NULL;
+	}
+
+	if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
+		blk_put_request(rq);
+		sdev_printk(KERN_INFO, sdev,
+				"get_rdac_req: blk_rq_map_kern failed.\n");
+		return NULL;
+	}
+
+	memset(&rq->cmd, 0, BLK_MAX_CDB);
+	rq->sense = h->sense;
+	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+	rq->sense_len = 0;
+
+	rq->cmd_type = REQ_TYPE_BLOCK_PC;
+	rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
+	rq->retries = RDAC_RETRIES;
+	rq->timeout = RDAC_TIMEOUT;
+
+	return rq;
+}
+
+static struct request *rdac_failover_get(struct scsi_device *sdev)
+{
+	struct request *rq;
+	struct rdac_mode_common *common;
+	unsigned data_size;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	if (h->ctlr->use_ms10) {
+		struct rdac_pg_expanded *rdac_pg;
+
+		data_size = sizeof(struct rdac_pg_expanded);
+		rdac_pg = &h->ctlr->mode_select.expanded;
+		memset(rdac_pg, 0, data_size);
+		common = &rdac_pg->common;
+		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
+		rdac_pg->subpage_code = 0x1;
+		rdac_pg->page_len[0] = 0x01;
+		rdac_pg->page_len[1] = 0x28;
+		rdac_pg->lun_table[h->lun] = 0x81;
+	} else {
+		struct rdac_pg_legacy *rdac_pg;
+
+		data_size = sizeof(struct rdac_pg_legacy);
+		rdac_pg = &h->ctlr->mode_select.legacy;
+		memset(rdac_pg, 0, data_size);
+		common = &rdac_pg->common;
+		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
+		rdac_pg->page_len = 0x68;
+		rdac_pg->lun_table[h->lun] = 0x81;
+	}
+	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
+	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
+	common->rdac_options = RDAC_FORCED_QUIESENCE;
+
+	/* get request for block layer packet command */
+	rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
+	if (!rq)
+		return NULL;
+
+	/* Prepare the command. */
+	if (h->ctlr->use_ms10) {
+		rq->cmd[0] = MODE_SELECT_10;
+		rq->cmd[7] = data_size >> 8;
+		rq->cmd[8] = data_size & 0xff;
+	} else {
+		rq->cmd[0] = MODE_SELECT;
+		rq->cmd[4] = data_size;
+	}
+	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+	return rq;
+}
+
+static void release_controller(struct kref *kref)
+{
+	struct rdac_controller *ctlr;
+	ctlr = container_of(kref, struct rdac_controller, kref);
+
+	spin_lock(&list_lock);
+	list_del(&ctlr->node);
+	spin_unlock(&list_lock);
+	kfree(ctlr);
+}
+
+static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id)
+{
+	struct rdac_controller *ctlr, *tmp;
+
+	spin_lock(&list_lock);
+
+	list_for_each_entry(tmp, &ctlr_list, node) {
+		if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
+			  (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
+			kref_get(&tmp->kref);
+			spin_unlock(&list_lock);
+			return tmp;
+		}
+	}
+	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
+	if (!ctlr)
+		goto done;
+
+	/* initialize fields of controller */
+	memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
+	memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
+	kref_init(&ctlr->kref);
+	ctlr->use_ms10 = -1;
+	list_add(&ctlr->node, &ctlr_list);
+done:
+	spin_unlock(&list_lock);
+	return ctlr;
+}
+
+static int submit_inquiry(struct scsi_device *sdev, int page_code,
+		unsigned int len)
+{
+	struct request *rq;
+	struct request_queue *q = sdev->request_queue;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	int err = SCSI_DH_RES_TEMP_UNAVAIL;
+
+	rq = get_rdac_req(sdev, &h->inq, len, READ);
+	if (!rq)
+		goto done;
+
+	/* Prepare the command. */
+	rq->cmd[0] = INQUIRY;
+	rq->cmd[1] = 1;
+	rq->cmd[2] = page_code;
+	rq->cmd[4] = len;
+	rq->cmd_len = COMMAND_SIZE(INQUIRY);
+	err = blk_execute_rq(q, NULL, rq, 1);
+	if (err == -EIO)
+		err = SCSI_DH_IO;
+done:
+	return err;
+}
+
+static int get_lun(struct scsi_device *sdev)
+{
+	int err;
+	struct c8_inquiry *inqp;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry));
+	if (err == SCSI_DH_OK) {
+		inqp = &h->inq.c8;
+		h->lun = inqp->lun[7]; /* currently it uses only one byte */
+	}
+	return err;
+}
+
+#define RDAC_OWNED	0
+#define RDAC_UNOWNED	1
+#define RDAC_FAILED	2
+static int check_ownership(struct scsi_device *sdev)
+{
+	int err;
+	struct c9_inquiry *inqp;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry));
+	if (err == SCSI_DH_OK) {
+		err = RDAC_UNOWNED;
+		inqp = &h->inq.c9;
+		/*
+		 * If in AVT mode or if the path already owns the LUN,
+		 * return RDAC_OWNED;
+		 */
+		if (((inqp->avte_cvp >> 7) == 0x1) ||
+				 ((inqp->avte_cvp & 0x1) != 0))
+			err = RDAC_OWNED;
+	} else
+		err = RDAC_FAILED;
+	return err;
+}
+
+static int initialize_controller(struct scsi_device *sdev)
+{
+	int err;
+	struct c4_inquiry *inqp;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry));
+	if (err == SCSI_DH_OK) {
+		inqp = &h->inq.c4;
+		h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id);
+		if (!h->ctlr)
+			err = SCSI_DH_RES_TEMP_UNAVAIL;
+	}
+	return err;
+}
+
+static int set_mode_select(struct scsi_device *sdev)
+{
+	int err;
+	struct c2_inquiry *inqp;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+
+	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry));
+	if (err == SCSI_DH_OK) {
+		inqp = &h->inq.c2;
+		/*
+		 * If more than MODE6_MAX_LUN luns are supported, use
+		 * mode select 10
+		 */
+		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
+			h->ctlr->use_ms10 = 1;
+		else
+			h->ctlr->use_ms10 = 0;
+	}
+	return err;
+}
+
+static int mode_select_handle_sense(struct scsi_device *sdev)
+{
+	struct scsi_sense_hdr sense_hdr;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	int sense, err = SCSI_DH_IO, ret;
+
+	ret = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
+	if (!ret)
+		goto done;
+
+	err = SCSI_DH_OK;
+	sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
+			sense_hdr.ascq;
+	/* If it is retryable failure, submit the c9 inquiry again */
+	if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
+			    sense == 0x62900) {
+		/* 0x59136    - Command lock contention
+		 * 0x[6b]8b02 - Quiesense in progress or achieved
+		 * 0x62900    - Power On, Reset, or Bus Device Reset
+		 */
+		err = SCSI_DH_RETRY;
+	}
+
+	if (sense)
+		sdev_printk(KERN_INFO, sdev,
+			"MODE_SELECT failed with sense 0x%x.\n", sense);
+done:
+	return err;
+}
+
+static int send_mode_select(struct scsi_device *sdev)
+{
+	struct request *rq;
+	struct request_queue *q = sdev->request_queue;
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	int err = SCSI_DH_RES_TEMP_UNAVAIL;
+
+	rq = rdac_failover_get(sdev);
+	if (!rq)
+		goto done;
+
+	sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n");
+
+	err = blk_execute_rq(q, NULL, rq, 1);
+	if (err != SCSI_DH_OK)
+		err = mode_select_handle_sense(sdev);
+	if (err == SCSI_DH_OK)
+		h->state = RDAC_STATE_ACTIVE;
+done:
+	return err;
+}
+
+static int rdac_activate(struct scsi_device *sdev)
+{
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	int err = SCSI_DH_OK;
+
+	if (h->lun == UNINITIALIZED_LUN) {
+		err = get_lun(sdev);
+		if (err != SCSI_DH_OK)
+			goto done;
+	}
+
+	err = check_ownership(sdev);
+	switch (err) {
+	case RDAC_UNOWNED:
+		break;
+	case RDAC_OWNED:
+		err = SCSI_DH_OK;
+		goto done;
+	case RDAC_FAILED:
+	default:
+		err = SCSI_DH_IO;
+		goto done;
+	}
+
+	if (!h->ctlr) {
+		err = initialize_controller(sdev);
+		if (err != SCSI_DH_OK)
+			goto done;
+	}
+
+	if (h->ctlr->use_ms10 == -1) {
+		err = set_mode_select(sdev);
+		if (err != SCSI_DH_OK)
+			goto done;
+	}
+
+	err = send_mode_select(sdev);
+done:
+	return err;
+}
+
+static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
+{
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	int ret = BLKPREP_OK;
+
+	if (h->state != RDAC_STATE_ACTIVE) {
+		ret = BLKPREP_KILL;
+		req->cmd_flags |= REQ_QUIET;
+	}
+	return ret;
+
+}
+
+static int rdac_check_sense(struct scsi_device *sdev,
+				struct scsi_sense_hdr *sense_hdr)
+{
+	struct rdac_dh_data *h = get_rdac_data(sdev);
+	switch (sense_hdr->sense_key) {
+	case NOT_READY:
+		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
+			/* LUN Not Ready - Storage firmware incompatible
+			 * Manual code synchonisation required.
+			 *
+			 * Nothing we can do here. Try to bypass the path.
+			 */
+			return SUCCESS;
+		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
+			/* LUN Not Ready - Quiescense in progress
+			 *
+			 * Just retry and wait.
+			 */
+			return NEEDS_RETRY;
+		break;
+	case ILLEGAL_REQUEST:
+		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
+			/* Invalid Request - Current Logical Unit Ownership.
+			 * Controller is not the current owner of the LUN,
+			 * Fail the path, so that the other path be used.
+			 */
+			h->state = RDAC_STATE_PASSIVE;
+			return SUCCESS;
+		}
+		break;
+	case UNIT_ATTENTION:
+		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
+			/*
+			 * Power On, Reset, or Bus Device Reset, just retry.
+			 */
+			return NEEDS_RETRY;
+		break;
+	}
+	/* success just means we do not care what scsi-ml does */
+	return SCSI_RETURN_NOT_HANDLED;
+}
+
+static const struct {
+	char *vendor;
+	char *model;
+} rdac_dev_list[] = {
+	{"IBM", "1722"},
+	{"IBM", "1724"},
+	{"IBM", "1726"},
+	{"IBM", "1742"},
+	{"IBM", "1814"},
+	{"IBM", "1815"},
+	{"IBM", "1818"},
+	{"IBM", "3526"},
+	{"SGI", "TP9400"},
+	{"SGI", "TP9500"},
+	{"SGI", "IS"},
+	{"STK", "OPENstorage D280"},
+	{"SUN", "CSM200_R"},
+	{"SUN", "LCSM100_F"},
+	{NULL, NULL},
+};
+
+static int rdac_bus_notify(struct notifier_block *, unsigned long, void *);
+
+static struct scsi_device_handler rdac_dh = {
+	.name = RDAC_NAME,
+	.module = THIS_MODULE,
+	.nb.notifier_call = rdac_bus_notify,
+	.prep_fn = rdac_prep_fn,
+	.check_sense = rdac_check_sense,
+	.activate = rdac_activate,
+};
+
+/*
+ * TODO: need some interface so we can set trespass values
+ */
+static int rdac_bus_notify(struct notifier_block *nb,
+			    unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_dh_data *scsi_dh_data;
+	struct rdac_dh_data *h;
+	int i, found = 0;
+	unsigned long flags;
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		for (i = 0; rdac_dev_list[i].vendor; i++) {
+			if (!strncmp(sdev->vendor, rdac_dev_list[i].vendor,
+				     strlen(rdac_dev_list[i].vendor)) &&
+			    !strncmp(sdev->model, rdac_dev_list[i].model,
+				     strlen(rdac_dev_list[i].model))) {
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			goto out;
+
+		scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+				+ sizeof(*h) , GFP_KERNEL);
+		if (!scsi_dh_data) {
+			sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
+				    RDAC_NAME);
+			goto out;
+		}
+
+		scsi_dh_data->scsi_dh = &rdac_dh;
+		h = (struct rdac_dh_data *) scsi_dh_data->buf;
+		h->lun = UNINITIALIZED_LUN;
+		h->state = RDAC_STATE_ACTIVE;
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		sdev->scsi_dh_data = scsi_dh_data;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+		try_module_get(THIS_MODULE);
+
+		sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", RDAC_NAME);
+
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		if (sdev->scsi_dh_data == NULL ||
+				sdev->scsi_dh_data->scsi_dh != &rdac_dh)
+			goto out;
+
+		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+		scsi_dh_data = sdev->scsi_dh_data;
+		sdev->scsi_dh_data = NULL;
+		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+		h = (struct rdac_dh_data *) scsi_dh_data->buf;
+		if (h->ctlr)
+			kref_put(&h->ctlr->kref, release_controller);
+		kfree(scsi_dh_data);
+		module_put(THIS_MODULE);
+		sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n", RDAC_NAME);
+	}
+
+out:
+	return 0;
+}
+
+static int __init rdac_init(void)
+{
+	int r;
+
+	r = scsi_register_device_handler(&rdac_dh);
+	if (r != 0)
+		printk(KERN_ERR "Failed to register scsi device handler.");
+	return r;
+}
+
+static void __exit rdac_exit(void)
+{
+	scsi_unregister_device_handler(&rdac_dh);
+}
+
+module_init(rdac_init);
+module_exit(rdac_exit);
+
+MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver");
+MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
+MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index eaf5a8add1ba..006a95916f72 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -298,6 +298,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
  */
 static int scsi_check_sense(struct scsi_cmnd *scmd)
 {
+	struct scsi_device *sdev = scmd->device;
 	struct scsi_sense_hdr sshdr;
 
 	if (! scsi_command_normalize_sense(scmd, &sshdr))
@@ -306,6 +307,16 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
 	if (scsi_sense_is_deferred(&sshdr))
 		return NEEDS_RETRY;
 
+	if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
+			sdev->scsi_dh_data->scsi_dh->check_sense) {
+		int rc;
+
+		rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
+		if (rc != SCSI_RETURN_NOT_HANDLED)
+			return rc;
+		/* handler does not care. Drop down to default handling */
+	}
+
 	/*
 	 * Previous logic looked for FILEMARK, EOM or ILI which are
 	 * mainly associated with tapes and returned SUCCESS.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a82d2fe80fb5..033c58a65f50 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1160,6 +1160,14 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 
 	if (ret != BLKPREP_OK)
 		return ret;
+
+	if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
+			 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
+		ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
+		if (ret != BLKPREP_OK)
+			return ret;
+	}
+
 	/*
 	 * Filesystem requests must transfer data.
 	 */
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 049103f1d16f..993b797f0de2 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -434,6 +434,7 @@ struct bus_type scsi_bus_type = {
 	.resume		= scsi_bus_resume,
 	.remove		= scsi_bus_remove,
 };
+EXPORT_SYMBOL_GPL(scsi_bus_type);
 
 int scsi_sysfs_register(void)
 {
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 32742c4563de..2b5b9356c314 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -400,6 +400,7 @@ struct scsi_lun {
 #define SOFT_ERROR      0x2005
 #define ADD_TO_MLQUEUE  0x2006
 #define TIMEOUT_ERROR   0x2007
+#define SCSI_RETURN_NOT_HANDLED   0x2008
 
 /*
  * Midlevel queue return values.
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 00b78763a1bf..6467f78b191f 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -162,9 +162,29 @@ struct scsi_device {
 
 	struct execute_work	ew; /* used to get process context on put */
 
+	struct scsi_dh_data	*scsi_dh_data;
 	enum scsi_device_state sdev_state;
 	unsigned long		sdev_data[0];
 } __attribute__((aligned(sizeof(unsigned long))));
+
+struct scsi_device_handler {
+	/* Used by the infrastructure */
+	struct list_head list; /* list of scsi_device_handlers */
+	struct notifier_block nb;
+
+	/* Filled by the hardware handler */
+	struct module *module;
+	const char *name;
+	int (*check_sense)(struct scsi_device *, struct scsi_sense_hdr *);
+	int (*activate)(struct scsi_device *);
+	int (*prep_fn)(struct scsi_device *, struct request *);
+};
+
+struct scsi_dh_data {
+	struct scsi_device_handler *scsi_dh;
+	char buf[0];
+};
+
 #define	to_scsi_device(d)	\
 	container_of(d, struct scsi_device, sdev_gendev)
 #define	class_to_sdev(d)	\
@@ -231,7 +251,9 @@ extern struct scsi_device *__scsi_add_device(struct Scsi_Host *,
 		uint, uint, uint, void *hostdata);
 extern int scsi_add_device(struct Scsi_Host *host, uint channel,
 			   uint target, uint lun);
+extern int scsi_register_device_handler(struct scsi_device_handler *scsi_dh);
 extern void scsi_remove_device(struct scsi_device *);
+extern int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh);
 
 extern int scsi_device_get(struct scsi_device *);
 extern void scsi_device_put(struct scsi_device *);
diff --git a/include/scsi/scsi_dh.h b/include/scsi/scsi_dh.h
new file mode 100644
index 000000000000..04d0d8495c83
--- /dev/null
+++ b/include/scsi/scsi_dh.h
@@ -0,0 +1,59 @@
+/*
+ * Header file for SCSI device handler infrastruture.
+ *
+ * Modified version of patches posted by Mike Christie <michaelc@cs.wisc.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2007
+ *      Authors:
+ *               Chandra Seetharaman <sekharan@us.ibm.com>
+ *               Mike Anderson <andmike@linux.vnet.ibm.com>
+ */
+
+#include <scsi/scsi_device.h>
+
+enum {
+	SCSI_DH_OK = 0,
+	/*
+	 * device errors
+	 */
+	SCSI_DH_DEV_FAILED,	/* generic device error */
+	SCSI_DH_DEV_TEMP_BUSY,
+	SCSI_DH_DEVICE_MAX,	/* max device blkerr definition */
+
+	/*
+	 * transport errors
+	 */
+	SCSI_DH_NOTCONN = SCSI_DH_DEVICE_MAX + 1,
+	SCSI_DH_CONN_FAILURE,
+	SCSI_DH_TRANSPORT_MAX,	/* max transport blkerr definition */
+
+	/*
+	 * driver and generic errors
+	 */
+	SCSI_DH_IO = SCSI_DH_TRANSPORT_MAX + 1,	/* generic error */
+	SCSI_DH_INVALID_IO,
+	SCSI_DH_RETRY,		/* retry the req, but not immediately */
+	SCSI_DH_IMM_RETRY,	/* immediately retry the req */
+	SCSI_DH_TIMED_OUT,
+	SCSI_DH_RES_TEMP_UNAVAIL,
+	SCSI_DH_DEV_OFFLINED,
+	SCSI_DH_NOSYS,
+	SCSI_DH_DRIVER_MAX,
+};
+
+extern int scsi_dh_activate(struct request_queue *);
+extern int scsi_dh_handler_exist(const char *);