[PATCH 6/7] scsi_dh: Remove hardware handlers from dm

[Chandra Seetharaman <sekharan@us.ibm.com>]

Subject: scsi_dh: Remove hardware handlers from dm

From: Chandra Seetharaman <sekharan@us.ibm.com>

This patch removes the 3 hardware handlers that currently exist 
under dm as they are moved to SCSI layer in the previous patches.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
---
 drivers/md/Kconfig          |   18 	0 +	18 -	0 !
 drivers/md/Makefile         |    3 	0 +	3 -	0 !
 drivers/md/dm-emc.c         |  347 	0 +	347 -	0 !
 drivers/md/dm-mpath-hp-sw.c |  248 	0 +	248 -	0 !
 drivers/md/dm-mpath-rdac.c  |  701 	0 +	701 -	0 !
 5 files changed, 1317 deletions(-)

Index: linux-2.6.25-rc3-mm1/drivers/md/Kconfig
===================================================================
--- linux-2.6.25-rc3-mm1.orig/drivers/md/Kconfig
+++ linux-2.6.25-rc3-mm1/drivers/md/Kconfig
@@ -256,24 +256,6 @@ config DM_MULTIPATH
 	---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
Index: linux-2.6.25-rc3-mm1/drivers/md/Makefile
===================================================================
--- linux-2.6.25-rc3-mm1.orig/drivers/md/Makefile
+++ linux-2.6.25-rc3-mm1/drivers/md/Makefile
@@ -35,9 +35,6 @@ 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-$(CONFIG_DM_MIRROR)		+= dm-mirror.o
 obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
Index: linux-2.6.25-rc3-mm1/drivers/md/dm-emc.c
===================================================================
--- linux-2.6.25-rc3-mm1.orig/drivers/md/dm-emc.c
+++ /dev/null
@@ -1,347 +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;
-
-	memset(&rq->cmd, 0, BLK_MAX_CDB);
-
-	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");
Index: linux-2.6.25-rc3-mm1/drivers/md/dm-mpath-hp-sw.c
===================================================================
--- linux-2.6.25-rc3-mm1.orig/drivers/md/dm-mpath-hp-sw.c
+++ /dev/null
@@ -1,248 +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);
-
-	memset(&req->cmd, 0, BLK_MAX_CDB);
-	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);
Index: linux-2.6.25-rc3-mm1/drivers/md/dm-mpath-rdac.c
===================================================================
--- linux-2.6.25-rc3-mm1.orig/drivers/md/dm-mpath-rdac.c
+++ /dev/null
@@ -1,701 +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;
-	}
-
- 	memset(&rq->cmd, 0, BLK_MAX_CDB);
-	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);

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------