drivers/scsi/device_handler/scsi_dh_rdac.c - kernel/msm-4.19 - Gitiles

 /*
  * 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"
 #define RDAC_RETRY_COUNT 5

 /*
  * 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;

 #define RDAC_LUN_UNOWNED	0
 #define RDAC_LUN_OWNED		1
 #define RDAC_LUN_AVT		2
 	char			lun_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 const char *lun_state[] =
 {
 	"unowned",
 	"owned",
 	"owned (AVT mode)",
 };

 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;

 	rq = blk_get_request(q, rw, GFP_NOIO);

 	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_NOIO)) {
 		blk_put_request(rq);
 		sdev_printk(KERN_INFO, sdev,
 				"get_rdac_req: blk_rq_map_kern failed.\n");
 		return NULL;
 	}

 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
 	rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 			 REQ_FAILFAST_DRIVER;
 	rq->retries = RDAC_RETRIES;
 	rq->timeout = RDAC_TIMEOUT;

 	return rq;
 }

 static struct request *rdac_failover_get(struct scsi_device *sdev,
 					 struct rdac_dh_data *h)
 {
 	struct request *rq;
 	struct rdac_mode_common *common;
 	unsigned data_size;

 	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]);

 	rq->sense = h->sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 	rq->sense_len = 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 rdac_dh_data *h)
 {
 	struct request *rq;
 	struct request_queue *q = sdev->request_queue;
 	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);

 	rq->sense = h->sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 	rq->sense_len = 0;

 	err = blk_execute_rq(q, NULL, rq, 1);
 	if (err == -EIO)
 		err = SCSI_DH_IO;

 	blk_put_request(rq);
 done:
 	return err;
 }

 static int get_lun(struct scsi_device *sdev, struct rdac_dh_data *h)
 {
 	int err;
 	struct c8_inquiry *inqp;

 	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
 	if (err == SCSI_DH_OK) {
 		inqp = &h->inq.c8;
 		if (inqp->page_code != 0xc8)
 			return SCSI_DH_NOSYS;
 		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
 		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
 			return SCSI_DH_NOSYS;
 		h->lun = inqp->lun[7]; /* Uses only the last byte */
 	}
 	return err;
 }

 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
 {
 	int err;
 	struct c9_inquiry *inqp;

 	h->lun_state = RDAC_LUN_UNOWNED;
 	h->state = RDAC_STATE_ACTIVE;
 	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
 	if (err == SCSI_DH_OK) {
 		inqp = &h->inq.c9;
 		if ((inqp->avte_cvp >> 7) == 0x1) {
 			/* LUN in AVT mode */
 			sdev_printk(KERN_NOTICE, sdev,
 				    "%s: AVT mode detected\n",
 				    RDAC_NAME);
 			h->lun_state = RDAC_LUN_AVT;
 		} else if ((inqp->avte_cvp & 0x1) != 0) {
 			/* LUN was owned by the controller */
 			h->lun_state = RDAC_LUN_OWNED;
 		}
 	}

 	if (h->lun_state == RDAC_LUN_UNOWNED)
 		h->state = RDAC_STATE_PASSIVE;

 	return err;
 }

 static int initialize_controller(struct scsi_device *sdev,
 				 struct rdac_dh_data *h)
 {
 	int err;
 	struct c4_inquiry *inqp;

 	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
 	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, struct rdac_dh_data *h)
 {
 	int err;
 	struct c2_inquiry *inqp;

 	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
 	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,
 				    unsigned char *sensebuf)
 {
 	struct scsi_sense_hdr sense_hdr;
 	int err = SCSI_DH_IO, ret;

 	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
 	if (!ret)
 		goto done;

 	err = SCSI_DH_OK;

 	switch (sense_hdr.sense_key) {
 	case NO_SENSE:
 	case ABORTED_COMMAND:
 	case UNIT_ATTENTION:
 		err = SCSI_DH_RETRY;
 		break;
 	case NOT_READY:
 		if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
 			/* LUN Not Ready and is in the Process of Becoming
 			 * Ready
 			 */
 			err = SCSI_DH_RETRY;
 		break;
 	case ILLEGAL_REQUEST:
 		if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
 			/*
 			 * Command Lock contention
 			 */
 			err = SCSI_DH_RETRY;
 		break;
 	default:
 		sdev_printk(KERN_INFO, sdev,
 			    "MODE_SELECT failed with sense %02x/%02x/%02x.\n",
 			    sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);
 	}

 done:
 	return err;
 }

 static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
 {
 	struct request *rq;
 	struct request_queue *q = sdev->request_queue;
 	int err, retry_cnt = RDAC_RETRY_COUNT;

 retry:
 	err = SCSI_DH_RES_TEMP_UNAVAIL;
 	rq = rdac_failover_get(sdev, h);
 	if (!rq)
 		goto done;

 	sdev_printk(KERN_INFO, sdev, "%s MODE_SELECT command.\n",
 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");

 	err = blk_execute_rq(q, NULL, rq, 1);
 	blk_put_request(rq);
 	if (err != SCSI_DH_OK) {
 		err = mode_select_handle_sense(sdev, h->sense);
 		if (err == SCSI_DH_RETRY && retry_cnt--)
 			goto retry;
 	}
 	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;

 	err = check_ownership(sdev, h);
 	if (err != SCSI_DH_OK)
 		goto done;

 	if (!h->ctlr) {
 		err = initialize_controller(sdev, h);
 		if (err != SCSI_DH_OK)
 			goto done;
 	}

 	if (h->ctlr->use_ms10 == -1) {
 		err = set_mode_select(sdev, h);
 		if (err != SCSI_DH_OK)
 			goto done;
 	}
 	if (h->lun_state == RDAC_LUN_UNOWNED)
 		err = send_mode_select(sdev, h);
 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 == 0x01)
 			/* LUN Not Ready - Logical Unit Not Ready and is in
 			* the process of becoming ready
 			* Just retry.
 			*/
 			return ADD_TO_MLQUEUE;
 		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 ADD_TO_MLQUEUE;
 		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
 			/* LUN Not Ready - Quiescense in progress
 			 * or has been achieved
 			 * Just retry.
 			 */
 			return ADD_TO_MLQUEUE;
 		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 ADD_TO_MLQUEUE;
 		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
 			/*
 			 * Quiescence in progress , just retry.
 			 */
 			return ADD_TO_MLQUEUE;
 		break;
 	}
 	/* success just means we do not care what scsi-ml does */
 	return SCSI_RETURN_NOT_HANDLED;
 }

 static const struct scsi_dh_devlist 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"},
 	{"DELL", "MD3000"},
 	{"DELL", "MD3000i"},
 	{"LSI", "INF-01-00"},
 	{"ENGENIO", "INF-01-00"},
 	{NULL, NULL},
 };

 static int rdac_bus_attach(struct scsi_device *sdev);
 static void rdac_bus_detach(struct scsi_device *sdev);

 static struct scsi_device_handler rdac_dh = {
 	.name = RDAC_NAME,
 	.module = THIS_MODULE,
 	.devlist = rdac_dev_list,
 	.prep_fn = rdac_prep_fn,
 	.check_sense = rdac_check_sense,
 	.attach = rdac_bus_attach,
 	.detach = rdac_bus_detach,
 	.activate = rdac_activate,
 };

 static int rdac_bus_attach(struct scsi_device *sdev)
 {
 	struct scsi_dh_data *scsi_dh_data;
 	struct rdac_dh_data *h;
 	unsigned long flags;
 	int err;

 	scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
 			       + sizeof(*h) , GFP_KERNEL);
 	if (!scsi_dh_data) {
 		sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
 			    RDAC_NAME);
 		return 0;
 	}

 	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;

 	err = get_lun(sdev, h);
 	if (err != SCSI_DH_OK)
 		goto failed;

 	err = check_ownership(sdev, h);
 	if (err != SCSI_DH_OK)
 		goto failed;

 	if (!try_module_get(THIS_MODULE))
 		goto failed;

 	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,
 		    "%s: LUN %d (%s)\n",
 		    RDAC_NAME, h->lun, lun_state[(int)h->lun_state]);

 	return 0;

 failed:
 	kfree(scsi_dh_data);
 	sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
 		    RDAC_NAME);
 	return -EINVAL;
 }

 static void rdac_bus_detach( struct scsi_device *sdev )
 {
 	struct scsi_dh_data *scsi_dh_data;
 	struct rdac_dh_data *h;
 	unsigned long flags;

 	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, "%s: Detached\n", RDAC_NAME);
 }


 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");
	/*
	* 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"
	#define RDAC_RETRY_COUNT 5

	/*
	* 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;

	#define RDAC_LUN_UNOWNED 0
	#define RDAC_LUN_OWNED 1
	#define RDAC_LUN_AVT 2
	char lun_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 const char *lun_state[] =
	{
	"unowned",
	"owned",
	"owned (AVT mode)",
	};

	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;

	rq = blk_get_request(q, rw, GFP_NOIO);

	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_NOIO)) {
	blk_put_request(rq);
	sdev_printk(KERN_INFO, sdev,
	"get_rdac_req: blk_rq_map_kern failed.\n");
	return NULL;
	}

	rq->cmd_type = REQ_TYPE_BLOCK_PC;
	rq->cmd_flags \|= REQ_FAILFAST_DEV \| REQ_FAILFAST_TRANSPORT \|
	REQ_FAILFAST_DRIVER;
	rq->retries = RDAC_RETRIES;
	rq->timeout = RDAC_TIMEOUT;

	return rq;
	}

	static struct request rdac_failover_get(struct scsi_device sdev,
	struct rdac_dh_data *h)
	{
	struct request *rq;
	struct rdac_mode_common *common;
	unsigned data_size;

	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]);

	rq->sense = h->sense;
	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
	rq->sense_len = 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 rdac_dh_data *h)
	{
	struct request *rq;
	struct request_queue *q = sdev->request_queue;
	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);

	rq->sense = h->sense;
	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
	rq->sense_len = 0;

	err = blk_execute_rq(q, NULL, rq, 1);
	if (err == -EIO)
	err = SCSI_DH_IO;

	blk_put_request(rq);
	done:
	return err;
	}

	static int get_lun(struct scsi_device sdev, struct rdac_dh_data h)
	{
	int err;
	struct c8_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
	if (err == SCSI_DH_OK) {
	inqp = &h->inq.c8;
	if (inqp->page_code != 0xc8)
	return SCSI_DH_NOSYS;
	if (inqp->page_id[0] != 'e' \|\| inqp->page_id[1] != 'd' \|\|
	inqp->page_id[2] != 'i' \|\| inqp->page_id[3] != 'd')
	return SCSI_DH_NOSYS;
	h->lun = inqp->lun[7]; /* Uses only the last byte */
	}
	return err;
	}

	static int check_ownership(struct scsi_device sdev, struct rdac_dh_data h)
	{
	int err;
	struct c9_inquiry *inqp;

	h->lun_state = RDAC_LUN_UNOWNED;
	h->state = RDAC_STATE_ACTIVE;
	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
	if (err == SCSI_DH_OK) {
	inqp = &h->inq.c9;
	if ((inqp->avte_cvp >> 7) == 0x1) {
	/* LUN in AVT mode */
	sdev_printk(KERN_NOTICE, sdev,
	"%s: AVT mode detected\n",
	RDAC_NAME);
	h->lun_state = RDAC_LUN_AVT;
	} else if ((inqp->avte_cvp & 0x1) != 0) {
	/* LUN was owned by the controller */
	h->lun_state = RDAC_LUN_OWNED;
	}
	}

	if (h->lun_state == RDAC_LUN_UNOWNED)
	h->state = RDAC_STATE_PASSIVE;

	return err;
	}

	static int initialize_controller(struct scsi_device *sdev,
	struct rdac_dh_data *h)
	{
	int err;
	struct c4_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
	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, struct rdac_dh_data h)
	{
	int err;
	struct c2_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
	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,
	unsigned char *sensebuf)
	{
	struct scsi_sense_hdr sense_hdr;
	int err = SCSI_DH_IO, ret;

	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
	if (!ret)
	goto done;

	err = SCSI_DH_OK;

	switch (sense_hdr.sense_key) {
	case NO_SENSE:
	case ABORTED_COMMAND:
	case UNIT_ATTENTION:
	err = SCSI_DH_RETRY;
	break;
	case NOT_READY:
	if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
	/* LUN Not Ready and is in the Process of Becoming
	* Ready
	*/
	err = SCSI_DH_RETRY;
	break;
	case ILLEGAL_REQUEST:
	if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
	/*
	* Command Lock contention
	*/
	err = SCSI_DH_RETRY;
	break;
	default:
	sdev_printk(KERN_INFO, sdev,
	"MODE_SELECT failed with sense %02x/%02x/%02x.\n",
	sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);
	}

	done:
	return err;
	}

	static int send_mode_select(struct scsi_device sdev, struct rdac_dh_data h)
	{
	struct request *rq;
	struct request_queue *q = sdev->request_queue;
	int err, retry_cnt = RDAC_RETRY_COUNT;

	retry:
	err = SCSI_DH_RES_TEMP_UNAVAIL;
	rq = rdac_failover_get(sdev, h);
	if (!rq)
	goto done;

	sdev_printk(KERN_INFO, sdev, "%s MODE_SELECT command.\n",
	(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");

	err = blk_execute_rq(q, NULL, rq, 1);
	blk_put_request(rq);
	if (err != SCSI_DH_OK) {
	err = mode_select_handle_sense(sdev, h->sense);
	if (err == SCSI_DH_RETRY && retry_cnt--)
	goto retry;
	}
	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;

	err = check_ownership(sdev, h);
	if (err != SCSI_DH_OK)
	goto done;

	if (!h->ctlr) {
	err = initialize_controller(sdev, h);
	if (err != SCSI_DH_OK)
	goto done;
	}

	if (h->ctlr->use_ms10 == -1) {
	err = set_mode_select(sdev, h);
	if (err != SCSI_DH_OK)
	goto done;
	}
	if (h->lun_state == RDAC_LUN_UNOWNED)
	err = send_mode_select(sdev, h);
	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 == 0x01)
	/* LUN Not Ready - Logical Unit Not Ready and is in
	* the process of becoming ready
	* Just retry.
	*/
	return ADD_TO_MLQUEUE;
	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 ADD_TO_MLQUEUE;
	if (sense_hdr->asc == 0xA1 && sense_hdr->ascq == 0x02)
	/* LUN Not Ready - Quiescense in progress
	* or has been achieved
	* Just retry.
	*/
	return ADD_TO_MLQUEUE;
	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 ADD_TO_MLQUEUE;
	if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
	/*
	* Quiescence in progress , just retry.
	*/
	return ADD_TO_MLQUEUE;
	break;
	}
	/* success just means we do not care what scsi-ml does */
	return SCSI_RETURN_NOT_HANDLED;
	}

	static const struct scsi_dh_devlist 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"},
	{"DELL", "MD3000"},
	{"DELL", "MD3000i"},
	{"LSI", "INF-01-00"},
	{"ENGENIO", "INF-01-00"},
	{NULL, NULL},
	};

	static int rdac_bus_attach(struct scsi_device *sdev);
	static void rdac_bus_detach(struct scsi_device *sdev);

	static struct scsi_device_handler rdac_dh = {
	.name = RDAC_NAME,
	.module = THIS_MODULE,
	.devlist = rdac_dev_list,
	.prep_fn = rdac_prep_fn,
	.check_sense = rdac_check_sense,
	.attach = rdac_bus_attach,
	.detach = rdac_bus_detach,
	.activate = rdac_activate,
	};

	static int rdac_bus_attach(struct scsi_device *sdev)
	{
	struct scsi_dh_data *scsi_dh_data;
	struct rdac_dh_data *h;
	unsigned long flags;
	int err;

	scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
	+ sizeof(*h) , GFP_KERNEL);
	if (!scsi_dh_data) {
	sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
	RDAC_NAME);
	return 0;
	}

	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;

	err = get_lun(sdev, h);
	if (err != SCSI_DH_OK)
	goto failed;

	err = check_ownership(sdev, h);
	if (err != SCSI_DH_OK)
	goto failed;

	if (!try_module_get(THIS_MODULE))
	goto failed;

	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,
	"%s: LUN %d (%s)\n",
	RDAC_NAME, h->lun, lun_state[(int)h->lun_state]);

	return 0;

	failed:
	kfree(scsi_dh_data);
	sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
	RDAC_NAME);
	return -EINVAL;
	}

	static void rdac_bus_detach( struct scsi_device *sdev )
	{
	struct scsi_dh_data *scsi_dh_data;
	struct rdac_dh_data *h;
	unsigned long flags;

	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, "%s: Detached\n", RDAC_NAME);
	}



	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");