drivers/md/dm-mpath-rdac.c - android_kernel_htc_msm8960 - Gitiles

 /*
  * 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);
	/*
	* 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);