drivers/scsi/device_handler/scsi_dh_emc.c - kernel/msm-4.9 - Gitiles

 /*
  * Target driver for EMC CLARiiON AX/CX-series hardware.
  * Based on code from Lars Marowsky-Bree <lmb@suse.de>
  * and Ed Goggin <egoggin@emc.com>.
  *
  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
  * Copyright (C) 2006 Mike Christie
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2, or (at your option)
  * any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; see the file COPYING.  If not, write to
  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 #include <scsi/scsi.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_dh.h>
 #include <scsi/scsi_device.h>

 #define CLARIION_NAME			"emc_clariion"

 #define CLARIION_TRESPASS_PAGE		0x22
 #define CLARIION_BUFFER_SIZE		0x80
 #define CLARIION_TIMEOUT		(60 * HZ)
 #define CLARIION_RETRIES		3
 #define CLARIION_UNBOUND_LU		-1

 static unsigned char long_trespass[] = {
 	0, 0, 0, 0,
 	CLARIION_TRESPASS_PAGE,	/* Page code */
 	0x09,			/* Page length - 2 */
 	0x81,			/* Trespass code + Honor reservation bit */
 	0xff, 0xff,		/* Trespass target */
 	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
 };

 static unsigned char long_trespass_hr[] = {
 	0, 0, 0, 0,
 	CLARIION_TRESPASS_PAGE,	/* Page code */
 	0x09,			/* Page length - 2 */
 	0x01,			/* Trespass code + Honor reservation bit */
 	0xff, 0xff,		/* Trespass target */
 	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
 };

 static unsigned char short_trespass[] = {
 	0, 0, 0, 0,
 	CLARIION_TRESPASS_PAGE,	/* Page code */
 	0x02,			/* Page length - 2 */
 	0x81,			/* Trespass code + Honor reservation bit */
 	0xff,			/* Trespass target */
 };

 static unsigned char short_trespass_hr[] = {
 	0, 0, 0, 0,
 	CLARIION_TRESPASS_PAGE,	/* Page code */
 	0x02,			/* Page length - 2 */
 	0x01,			/* Trespass code + Honor reservation bit */
 	0xff,			/* Trespass target */
 };

 struct clariion_dh_data {
 	/*
 	 * Use short trespass command (FC-series) or the long version
 	 * (default for AX/CX CLARiiON arrays).
 	 */
 	unsigned short_trespass;
 	/*
 	 * Whether or not (default) to honor SCSI reservations when
 	 * initiating a switch-over.
 	 */
 	unsigned hr;
 	/* I/O buffer for both MODE_SELECT and INQUIRY commands. */
 	char buffer[CLARIION_BUFFER_SIZE];
 	/*
 	 * SCSI sense buffer for commands -- assumes serial issuance
 	 * and completion sequence of all commands for same multipath.
 	 */
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	/* which SP (A=0,B=1,UNBOUND=-1) is dflt SP for path's mapped dev */
 	int default_sp;
 	/* which SP (A=0,B=1,UNBOUND=-1) is active for path's mapped dev */
 	int current_sp;
 };

 static inline struct clariion_dh_data
 			*get_clariion_data(struct scsi_device *sdev)
 {
 	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
 	BUG_ON(scsi_dh_data == NULL);
 	return ((struct clariion_dh_data *) scsi_dh_data->buf);
 }

 /*
  * Parse MODE_SELECT cmd reply.
  */
 static int trespass_endio(struct scsi_device *sdev, int result)
 {
 	int err = SCSI_DH_OK;
 	struct scsi_sense_hdr sshdr;
 	struct clariion_dh_data *csdev = get_clariion_data(sdev);
 	char *sense = csdev->sense;

 	if (status_byte(result) == CHECK_CONDITION &&
 	    scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
 		sdev_printk(KERN_ERR, sdev, "Found valid sense data 0x%2x, "
 			    "0x%2x, 0x%2x while sending CLARiiON trespass "
 			    "command.\n", sshdr.sense_key, sshdr.asc,
 			     sshdr.ascq);

 		if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
 		     (sshdr.ascq == 0x00)) {
 			/*
 			 * Array based copy in progress -- do not send
 			 * mode_select or copy will be aborted mid-stream.
 			 */
 			sdev_printk(KERN_INFO, sdev, "Array Based Copy in "
 				    "progress while sending CLARiiON trespass "
 				    "command.\n");
 			err = SCSI_DH_DEV_TEMP_BUSY;
 		} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
 			    (sshdr.ascq == 0x03)) {
 			/*
 			 * LUN Not Ready - Manual Intervention Required
 			 * indicates in-progress ucode upgrade (NDU).
 			 */
 			sdev_printk(KERN_INFO, sdev, "Detected in-progress "
 				    "ucode upgrade NDU operation while sending "
 				    "CLARiiON trespass command.\n");
 			err = SCSI_DH_DEV_TEMP_BUSY;
 		} else
 			err = SCSI_DH_DEV_FAILED;
 	} else if (result) {
 		sdev_printk(KERN_ERR, sdev, "Error 0x%x while sending "
 			    "CLARiiON trespass command.\n", result);
 		err = SCSI_DH_IO;
 	}

 	return err;
 }

 static int parse_sp_info_reply(struct scsi_device *sdev, int result,
 		int *default_sp, int *current_sp, int *new_current_sp)
 {
 	int err = SCSI_DH_OK;
 	struct clariion_dh_data *csdev = get_clariion_data(sdev);

 	if (result == 0) {
 		/* check for in-progress ucode upgrade (NDU) */
 		if (csdev->buffer[48] != 0) {
 			sdev_printk(KERN_NOTICE, sdev, "Detected in-progress "
 			       "ucode upgrade NDU operation while finding "
 			       "current active SP.");
 			err = SCSI_DH_DEV_TEMP_BUSY;
 		} else {
 			*default_sp = csdev->buffer[5];

 			if (csdev->buffer[4] == 2)
 				/* SP for path is current */
 				*current_sp = csdev->buffer[8];
 			else {
 				if (csdev->buffer[4] == 1)
 					/* SP for this path is NOT current */
 					if (csdev->buffer[8] == 0)
 						*current_sp = 1;
 					else
 						*current_sp = 0;
 				else
 					/* unbound LU or LUNZ */
 					*current_sp = CLARIION_UNBOUND_LU;
 			}
 			*new_current_sp =  csdev->buffer[8];
 		}
 	} else {
 		struct scsi_sense_hdr sshdr;

 		err = SCSI_DH_IO;

 		if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
 							   &sshdr))
 			sdev_printk(KERN_ERR, sdev, "Found valid sense data "
 			      "0x%2x, 0x%2x, 0x%2x while finding current "
 			      "active SP.", sshdr.sense_key, sshdr.asc,
 			      sshdr.ascq);
 		else
 			sdev_printk(KERN_ERR, sdev, "Error 0x%x finding "
 			      "current active SP.", result);
 	}

 	return err;
 }

 static int sp_info_endio(struct scsi_device *sdev, int result,
 					int mode_select_sent, int *done)
 {
 	struct clariion_dh_data *csdev = get_clariion_data(sdev);
 	int err_flags, default_sp, current_sp, new_current_sp;

 	err_flags = parse_sp_info_reply(sdev, result, &default_sp,
 					     &current_sp, &new_current_sp);

 	if (err_flags != SCSI_DH_OK)
 		goto done;

 	if (mode_select_sent) {
 		csdev->default_sp = default_sp;
 		csdev->current_sp = current_sp;
 	} else {
 		/*
 		 * Issue the actual module_selec request IFF either
 		 * (1) we do not know the identity of the current SP OR
 		 * (2) what we think we know is actually correct.
 		 */
 		if ((current_sp != CLARIION_UNBOUND_LU) &&
 		    (new_current_sp != current_sp)) {

 			csdev->default_sp = default_sp;
 			csdev->current_sp = current_sp;

 			sdev_printk(KERN_INFO, sdev, "Ignoring path group "
 			       "switch-over command for CLARiiON SP%s since "
 			       " mapped device is already initialized.",
 			       current_sp ? "B" : "A");
 			if (done)
 				*done = 1; /* as good as doing it */
 		}
 	}
 done:
 	return err_flags;
 }

 /*
 * Get block request for REQ_BLOCK_PC command issued to path.  Currently
 * limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
 *
 * Uses data and sense buffers in hardware handler context structure and
 * assumes serial servicing of commands, both issuance and completion.
 */
 static struct request *get_req(struct scsi_device *sdev, int cmd)
 {
 	struct clariion_dh_data *csdev = get_clariion_data(sdev);
 	struct request *rq;
 	unsigned char *page22;
 	int len = 0;

 	rq = blk_get_request(sdev->request_queue,
 			(cmd == MODE_SELECT) ? WRITE : READ, GFP_ATOMIC);
 	if (!rq) {
 		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
 		return NULL;
 	}

 	memset(&rq->cmd, 0, BLK_MAX_CDB);
 	rq->cmd[0] = cmd;
 	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);

 	switch (cmd) {
 	case MODE_SELECT:
 		if (csdev->short_trespass) {
 			page22 = csdev->hr ? short_trespass_hr : short_trespass;
 			len = sizeof(short_trespass);
 		} else {
 			page22 = csdev->hr ? long_trespass_hr : long_trespass;
 			len = sizeof(long_trespass);
 		}
 		/*
 		 * Can't DMA from kernel BSS -- must copy selected trespass
 		 * command mode page contents to context buffer which is
 		 * allocated by kmalloc.
 		 */
 		BUG_ON((len > CLARIION_BUFFER_SIZE));
 		memcpy(csdev->buffer, page22, len);
 		rq->cmd_flags |= REQ_RW;
 		rq->cmd[1] = 0x10;
 		break;
 	case INQUIRY:
 		rq->cmd[1] = 0x1;
 		rq->cmd[2] = 0xC0;
 		len = CLARIION_BUFFER_SIZE;
 		memset(csdev->buffer, 0, CLARIION_BUFFER_SIZE);
 		break;
 	default:
 		BUG_ON(1);
 		break;
 	}

 	rq->cmd[4] = len;
 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
 	rq->cmd_flags |= REQ_FAILFAST;
 	rq->timeout = CLARIION_TIMEOUT;
 	rq->retries = CLARIION_RETRIES;

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

 	if (blk_rq_map_kern(sdev->request_queue, rq, csdev->buffer,
 							len, GFP_ATOMIC)) {
 		__blk_put_request(rq->q, rq);
 		return NULL;
 	}

 	return rq;
 }

 static int send_cmd(struct scsi_device *sdev, int cmd)
 {
 	struct request *rq = get_req(sdev, cmd);

 	if (!rq)
 		return SCSI_DH_RES_TEMP_UNAVAIL;

 	return blk_execute_rq(sdev->request_queue, NULL, rq, 1);
 }

 static int clariion_activate(struct scsi_device *sdev)
 {
 	int result, done = 0;

 	result = send_cmd(sdev, INQUIRY);
 	result = sp_info_endio(sdev, result, 0, &done);
 	if (result || done)
 		goto done;

 	result = send_cmd(sdev, MODE_SELECT);
 	result = trespass_endio(sdev, result);
 	if (result)
 		goto done;

 	result = send_cmd(sdev, INQUIRY);
 	result = sp_info_endio(sdev, result, 1, NULL);
 done:
 	return result;
 }

 static int clariion_check_sense(struct scsi_device *sdev,
 				struct scsi_sense_hdr *sense_hdr)
 {
 	switch (sense_hdr->sense_key) {
 	case NOT_READY:
 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
 			/*
 			 * LUN Not Ready - Manual Intervention Required
 			 * indicates this is a passive path.
 			 *
 			 * FIXME: However, if this is seen and EVPD C0
 			 * indicates that this is due to a NDU in
 			 * progress, we should set FAIL_PATH too.
 			 * This indicates we might have to do a SCSI
 			 * inquiry in the end_io path. Ugh.
 			 *
 			 * Can return FAILED only when we want the error
 			 * recovery process to kick in.
 			 */
 			return SUCCESS;
 		break;
 	case ILLEGAL_REQUEST:
 		if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
 			/*
 			 * An array based copy is in progress. Do not
 			 * fail the path, do not bypass to another PG,
 			 * do not retry. Fail the IO immediately.
 			 * (Actually this is the same conclusion as in
 			 * the default handler, but lets make sure.)
 			 *
 			 * Can return FAILED only when we want the error
 			 * recovery process to kick in.
 			 */
 			return SUCCESS;
 		break;
 	case UNIT_ATTENTION:
 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 			/*
 			 * Unit Attention Code. This is the first IO
 			 * to the new path, so just retry.
 			 */
 			return NEEDS_RETRY;
 		break;
 	}

 	/* success just means we do not care what scsi-ml does */
 	return SUCCESS;
 }

 static const struct {
 	char *vendor;
 	char *model;
 } clariion_dev_list[] = {
 	{"DGC", "RAID"},
 	{"DGC", "DISK"},
 	{NULL, NULL},
 };

 static int clariion_bus_notify(struct notifier_block *, unsigned long, void *);

 static struct scsi_device_handler clariion_dh = {
 	.name		= CLARIION_NAME,
 	.module		= THIS_MODULE,
 	.nb.notifier_call = clariion_bus_notify,
 	.check_sense	= clariion_check_sense,
 	.activate	= clariion_activate,
 };

 /*
  * TODO: need some interface so we can set trespass values
  */
 static int clariion_bus_notify(struct notifier_block *nb,
 				unsigned long action, void *data)
 {
 	struct device *dev = data;
 	struct scsi_device *sdev;
 	struct scsi_dh_data *scsi_dh_data;
 	struct clariion_dh_data *h;
 	int i, found = 0;
 	unsigned long flags;

 	if (!scsi_is_sdev_device(dev))
 		return 0;

 	sdev = to_scsi_device(dev);

 	if (action == BUS_NOTIFY_ADD_DEVICE) {
 		for (i = 0; clariion_dev_list[i].vendor; i++) {
 			if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
 				     strlen(clariion_dev_list[i].vendor)) &&
 			    !strncmp(sdev->model, clariion_dev_list[i].model,
 				     strlen(clariion_dev_list[i].model))) {
 				found = 1;
 				break;
 			}
 		}
 		if (!found)
 			goto out;

 		scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
 				+ sizeof(*h) , GFP_KERNEL);
 		if (!scsi_dh_data) {
 			sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
 				    CLARIION_NAME);
 			goto out;
 		}

 		scsi_dh_data->scsi_dh = &clariion_dh;
 		h = (struct clariion_dh_data *) scsi_dh_data->buf;
 		h->default_sp = CLARIION_UNBOUND_LU;
 		h->current_sp = CLARIION_UNBOUND_LU;

 		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 		sdev->scsi_dh_data = scsi_dh_data;
 		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

 		sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", CLARIION_NAME);
 		try_module_get(THIS_MODULE);

 	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
 		if (sdev->scsi_dh_data == NULL ||
 				sdev->scsi_dh_data->scsi_dh != &clariion_dh)
 			goto out;

 		spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 		scsi_dh_data = sdev->scsi_dh_data;
 		sdev->scsi_dh_data = NULL;
 		spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

 		sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n",
 			    CLARIION_NAME);

 		kfree(scsi_dh_data);
 		module_put(THIS_MODULE);
 	}

 out:
 	return 0;
 }

 static int __init clariion_init(void)
 {
 	int r;

 	r = scsi_register_device_handler(&clariion_dh);
 	if (r != 0)
 		printk(KERN_ERR "Failed to register scsi device handler.");
 	return r;
 }

 static void __exit clariion_exit(void)
 {
 	scsi_unregister_device_handler(&clariion_dh);
 }

 module_init(clariion_init);
 module_exit(clariion_exit);

 MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
 MODULE_LICENSE("GPL");
	/*
	* Target driver for EMC CLARiiON AX/CX-series hardware.
	* Based on code from Lars Marowsky-Bree <lmb@suse.de>
	* and Ed Goggin <egoggin@emc.com>.
	*
	* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
	* Copyright (C) 2006 Mike Christie
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2, or (at your option)
	* any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; see the file COPYING. If not, write to
	* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
	*/
	#include <scsi/scsi.h>
	#include <scsi/scsi_eh.h>
	#include <scsi/scsi_dh.h>
	#include <scsi/scsi_device.h>

	#define CLARIION_NAME "emc_clariion"

	#define CLARIION_TRESPASS_PAGE 0x22
	#define CLARIION_BUFFER_SIZE 0x80
	#define CLARIION_TIMEOUT (60 * HZ)
	#define CLARIION_RETRIES 3
	#define CLARIION_UNBOUND_LU -1

	static unsigned char long_trespass[] = {
	0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE, /* Page code */
	0x09, /* Page length - 2 */
	0x81, /* Trespass code + Honor reservation bit */
	0xff, 0xff, /* Trespass target */
	0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
	};

	static unsigned char long_trespass_hr[] = {
	0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE, /* Page code */
	0x09, /* Page length - 2 */
	0x01, /* Trespass code + Honor reservation bit */
	0xff, 0xff, /* Trespass target */
	0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
	};

	static unsigned char short_trespass[] = {
	0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE, /* Page code */
	0x02, /* Page length - 2 */
	0x81, /* Trespass code + Honor reservation bit */
	0xff, /* Trespass target */
	};

	static unsigned char short_trespass_hr[] = {
	0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE, /* Page code */
	0x02, /* Page length - 2 */
	0x01, /* Trespass code + Honor reservation bit */
	0xff, /* Trespass target */
	};

	struct clariion_dh_data {
	/*
	* Use short trespass command (FC-series) or the long version
	* (default for AX/CX CLARiiON arrays).
	*/
	unsigned short_trespass;
	/*
	* Whether or not (default) to honor SCSI reservations when
	* initiating a switch-over.
	*/
	unsigned hr;
	/* I/O buffer for both MODE_SELECT and INQUIRY commands. */
	char buffer[CLARIION_BUFFER_SIZE];
	/*
	* SCSI sense buffer for commands -- assumes serial issuance
	* and completion sequence of all commands for same multipath.
	*/
	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
	/* which SP (A=0,B=1,UNBOUND=-1) is dflt SP for path's mapped dev */
	int default_sp;
	/* which SP (A=0,B=1,UNBOUND=-1) is active for path's mapped dev */
	int current_sp;
	};

	static inline struct clariion_dh_data
	get_clariion_data(struct scsi_device sdev)
	{
	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
	BUG_ON(scsi_dh_data == NULL);
	return ((struct clariion_dh_data *) scsi_dh_data->buf);
	}

	/*
	* Parse MODE_SELECT cmd reply.
	*/
	static int trespass_endio(struct scsi_device *sdev, int result)
	{
	int err = SCSI_DH_OK;
	struct scsi_sense_hdr sshdr;
	struct clariion_dh_data *csdev = get_clariion_data(sdev);
	char *sense = csdev->sense;

	if (status_byte(result) == CHECK_CONDITION &&
	scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
	sdev_printk(KERN_ERR, sdev, "Found valid sense data 0x%2x, "
	"0x%2x, 0x%2x while sending CLARiiON trespass "
	"command.\n", sshdr.sense_key, sshdr.asc,
	sshdr.ascq);

	if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
	(sshdr.ascq == 0x00)) {
	/*
	* Array based copy in progress -- do not send
	* mode_select or copy will be aborted mid-stream.
	*/
	sdev_printk(KERN_INFO, sdev, "Array Based Copy in "
	"progress while sending CLARiiON trespass "
	"command.\n");
	err = SCSI_DH_DEV_TEMP_BUSY;
	} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
	(sshdr.ascq == 0x03)) {
	/*
	* LUN Not Ready - Manual Intervention Required
	* indicates in-progress ucode upgrade (NDU).
	*/
	sdev_printk(KERN_INFO, sdev, "Detected in-progress "
	"ucode upgrade NDU operation while sending "
	"CLARiiON trespass command.\n");
	err = SCSI_DH_DEV_TEMP_BUSY;
	} else
	err = SCSI_DH_DEV_FAILED;
	} else if (result) {
	sdev_printk(KERN_ERR, sdev, "Error 0x%x while sending "
	"CLARiiON trespass command.\n", result);
	err = SCSI_DH_IO;
	}

	return err;
	}

	static int parse_sp_info_reply(struct scsi_device *sdev, int result,
	int default_sp, int current_sp, int *new_current_sp)
	{
	int err = SCSI_DH_OK;
	struct clariion_dh_data *csdev = get_clariion_data(sdev);

	if (result == 0) {
	/* check for in-progress ucode upgrade (NDU) */
	if (csdev->buffer[48] != 0) {
	sdev_printk(KERN_NOTICE, sdev, "Detected in-progress "
	"ucode upgrade NDU operation while finding "
	"current active SP.");
	err = SCSI_DH_DEV_TEMP_BUSY;
	} else {
	*default_sp = csdev->buffer[5];

	if (csdev->buffer[4] == 2)
	/* SP for path is current */
	*current_sp = csdev->buffer[8];
	else {
	if (csdev->buffer[4] == 1)
	/* SP for this path is NOT current */
	if (csdev->buffer[8] == 0)
	*current_sp = 1;
	else
	*current_sp = 0;
	else
	/* unbound LU or LUNZ */
	*current_sp = CLARIION_UNBOUND_LU;
	}
	*new_current_sp = csdev->buffer[8];
	}
	} else {
	struct scsi_sense_hdr sshdr;

	err = SCSI_DH_IO;

	if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
	&sshdr))
	sdev_printk(KERN_ERR, sdev, "Found valid sense data "
	"0x%2x, 0x%2x, 0x%2x while finding current "
	"active SP.", sshdr.sense_key, sshdr.asc,
	sshdr.ascq);
	else
	sdev_printk(KERN_ERR, sdev, "Error 0x%x finding "
	"current active SP.", result);
	}

	return err;
	}

	static int sp_info_endio(struct scsi_device *sdev, int result,
	int mode_select_sent, int *done)
	{
	struct clariion_dh_data *csdev = get_clariion_data(sdev);
	int err_flags, default_sp, current_sp, new_current_sp;

	err_flags = parse_sp_info_reply(sdev, result, &default_sp,
	&current_sp, &new_current_sp);

	if (err_flags != SCSI_DH_OK)
	goto done;

	if (mode_select_sent) {
	csdev->default_sp = default_sp;
	csdev->current_sp = current_sp;
	} else {
	/*
	* Issue the actual module_selec request IFF either
	* (1) we do not know the identity of the current SP OR
	* (2) what we think we know is actually correct.
	*/
	if ((current_sp != CLARIION_UNBOUND_LU) &&
	(new_current_sp != current_sp)) {

	csdev->default_sp = default_sp;
	csdev->current_sp = current_sp;

	sdev_printk(KERN_INFO, sdev, "Ignoring path group "
	"switch-over command for CLARiiON SP%s since "
	" mapped device is already initialized.",
	current_sp ? "B" : "A");
	if (done)
	done = 1; / as good as doing it */
	}
	}
	done:
	return err_flags;
	}

	/*
	* Get block request for REQ_BLOCK_PC command issued to path. Currently
	* limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
	*
	* Uses data and sense buffers in hardware handler context structure and
	* assumes serial servicing of commands, both issuance and completion.
	*/
	static struct request get_req(struct scsi_device sdev, int cmd)
	{
	struct clariion_dh_data *csdev = get_clariion_data(sdev);
	struct request *rq;
	unsigned char *page22;
	int len = 0;

	rq = blk_get_request(sdev->request_queue,
	(cmd == MODE_SELECT) ? WRITE : READ, GFP_ATOMIC);
	if (!rq) {
	sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
	return NULL;
	}

	memset(&rq->cmd, 0, BLK_MAX_CDB);
	rq->cmd[0] = cmd;
	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);

	switch (cmd) {
	case MODE_SELECT:
	if (csdev->short_trespass) {
	page22 = csdev->hr ? short_trespass_hr : short_trespass;
	len = sizeof(short_trespass);
	} else {
	page22 = csdev->hr ? long_trespass_hr : long_trespass;
	len = sizeof(long_trespass);
	}
	/*
	* Can't DMA from kernel BSS -- must copy selected trespass
	* command mode page contents to context buffer which is
	* allocated by kmalloc.
	*/
	BUG_ON((len > CLARIION_BUFFER_SIZE));
	memcpy(csdev->buffer, page22, len);
	rq->cmd_flags \|= REQ_RW;
	rq->cmd[1] = 0x10;
	break;
	case INQUIRY:
	rq->cmd[1] = 0x1;
	rq->cmd[2] = 0xC0;
	len = CLARIION_BUFFER_SIZE;
	memset(csdev->buffer, 0, CLARIION_BUFFER_SIZE);
	break;
	default:
	BUG_ON(1);
	break;
	}

	rq->cmd[4] = len;
	rq->cmd_type = REQ_TYPE_BLOCK_PC;
	rq->cmd_flags \|= REQ_FAILFAST;
	rq->timeout = CLARIION_TIMEOUT;
	rq->retries = CLARIION_RETRIES;

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

	if (blk_rq_map_kern(sdev->request_queue, rq, csdev->buffer,
	len, GFP_ATOMIC)) {
	__blk_put_request(rq->q, rq);
	return NULL;
	}

	return rq;
	}

	static int send_cmd(struct scsi_device *sdev, int cmd)
	{
	struct request *rq = get_req(sdev, cmd);

	if (!rq)
	return SCSI_DH_RES_TEMP_UNAVAIL;

	return blk_execute_rq(sdev->request_queue, NULL, rq, 1);
	}

	static int clariion_activate(struct scsi_device *sdev)
	{
	int result, done = 0;

	result = send_cmd(sdev, INQUIRY);
	result = sp_info_endio(sdev, result, 0, &done);
	if (result \|\| done)
	goto done;

	result = send_cmd(sdev, MODE_SELECT);
	result = trespass_endio(sdev, result);
	if (result)
	goto done;

	result = send_cmd(sdev, INQUIRY);
	result = sp_info_endio(sdev, result, 1, NULL);
	done:
	return result;
	}

	static int clariion_check_sense(struct scsi_device *sdev,
	struct scsi_sense_hdr *sense_hdr)
	{
	switch (sense_hdr->sense_key) {
	case NOT_READY:
	if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
	/*
	* LUN Not Ready - Manual Intervention Required
	* indicates this is a passive path.
	*
	* FIXME: However, if this is seen and EVPD C0
	* indicates that this is due to a NDU in
	* progress, we should set FAIL_PATH too.
	* This indicates we might have to do a SCSI
	* inquiry in the end_io path. Ugh.
	*
	* Can return FAILED only when we want the error
	* recovery process to kick in.
	*/
	return SUCCESS;
	break;
	case ILLEGAL_REQUEST:
	if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
	/*
	* An array based copy is in progress. Do not
	* fail the path, do not bypass to another PG,
	* do not retry. Fail the IO immediately.
	* (Actually this is the same conclusion as in
	* the default handler, but lets make sure.)
	*
	* Can return FAILED only when we want the error
	* recovery process to kick in.
	*/
	return SUCCESS;
	break;
	case UNIT_ATTENTION:
	if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
	/*
	* Unit Attention Code. This is the first IO
	* to the new path, so just retry.
	*/
	return NEEDS_RETRY;
	break;
	}

	/* success just means we do not care what scsi-ml does */
	return SUCCESS;
	}

	static const struct {
	char *vendor;
	char *model;
	} clariion_dev_list[] = {
	{"DGC", "RAID"},
	{"DGC", "DISK"},
	{NULL, NULL},
	};

	static int clariion_bus_notify(struct notifier_block , unsigned long, void );

	static struct scsi_device_handler clariion_dh = {
	.name = CLARIION_NAME,
	.module = THIS_MODULE,
	.nb.notifier_call = clariion_bus_notify,
	.check_sense = clariion_check_sense,
	.activate = clariion_activate,
	};

	/*
	* TODO: need some interface so we can set trespass values
	*/
	static int clariion_bus_notify(struct notifier_block *nb,
	unsigned long action, void *data)
	{
	struct device *dev = data;
	struct scsi_device *sdev;
	struct scsi_dh_data *scsi_dh_data;
	struct clariion_dh_data *h;
	int i, found = 0;
	unsigned long flags;

	if (!scsi_is_sdev_device(dev))
	return 0;

	sdev = to_scsi_device(dev);

	if (action == BUS_NOTIFY_ADD_DEVICE) {
	for (i = 0; clariion_dev_list[i].vendor; i++) {
	if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
	strlen(clariion_dev_list[i].vendor)) &&
	!strncmp(sdev->model, clariion_dev_list[i].model,
	strlen(clariion_dev_list[i].model))) {
	found = 1;
	break;
	}
	}
	if (!found)
	goto out;

	scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
	+ sizeof(*h) , GFP_KERNEL);
	if (!scsi_dh_data) {
	sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
	CLARIION_NAME);
	goto out;
	}

	scsi_dh_data->scsi_dh = &clariion_dh;
	h = (struct clariion_dh_data *) scsi_dh_data->buf;
	h->default_sp = CLARIION_UNBOUND_LU;
	h->current_sp = CLARIION_UNBOUND_LU;

	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
	sdev->scsi_dh_data = scsi_dh_data;
	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

	sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", CLARIION_NAME);
	try_module_get(THIS_MODULE);

	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
	if (sdev->scsi_dh_data == NULL \|\|
	sdev->scsi_dh_data->scsi_dh != &clariion_dh)
	goto out;

	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
	scsi_dh_data = sdev->scsi_dh_data;
	sdev->scsi_dh_data = NULL;
	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

	sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n",
	CLARIION_NAME);

	kfree(scsi_dh_data);
	module_put(THIS_MODULE);
	}

	out:
	return 0;
	}

	static int __init clariion_init(void)
	{
	int r;

	r = scsi_register_device_handler(&clariion_dh);
	if (r != 0)
	printk(KERN_ERR "Failed to register scsi device handler.");
	return r;
	}

	static void __exit clariion_exit(void)
	{
	scsi_unregister_device_handler(&clariion_dh);
	}

	module_init(clariion_init);
	module_exit(clariion_exit);

	MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
	MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
	MODULE_LICENSE("GPL");