/drivers/scsi/ibmvscsi/ibmvfc.c

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/*
 * ibmvfc.c -- driver for IBM Power Virtual Fibre Channel Adapter
 *
 * Written By: Brian King <brking@linux.vnet.ibm.com>, IBM Corporation
 *
 * Copyright (C) IBM Corporation, 2008
 *
 * 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 <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kthread.h>
#include <linux/of.h>
#include <linux/stringify.h>
#include <asm/firmware.h>
#include <asm/irq.h>
#include <asm/vio.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_transport_fc.h>
#include "ibmvfc.h"

static unsigned int init_timeout = IBMVFC_INIT_TIMEOUT;
static unsigned int default_timeout = IBMVFC_DEFAULT_TIMEOUT;
static unsigned int max_lun = IBMVFC_MAX_LUN;
static unsigned int max_targets = IBMVFC_MAX_TARGETS;
static unsigned int max_requests = IBMVFC_MAX_REQUESTS_DEFAULT;
static unsigned int disc_threads = IBMVFC_MAX_DISC_THREADS;
static unsigned int dev_loss_tmo = IBMVFC_DEV_LOSS_TMO;
static unsigned int ibmvfc_debug = IBMVFC_DEBUG;
static unsigned int log_level = IBMVFC_DEFAULT_LOG_LEVEL;
static LIST_HEAD(ibmvfc_head);
static DEFINE_SPINLOCK(ibmvfc_driver_lock);
static struct scsi_transport_template *ibmvfc_transport_template;

MODULE_DESCRIPTION("IBM Virtual Fibre Channel Driver");
MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION(IBMVFC_DRIVER_VERSION);

module_param_named(init_timeout, init_timeout, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds. "
		 "[Default=" __stringify(IBMVFC_INIT_TIMEOUT) "]");
module_param_named(default_timeout, default_timeout, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(default_timeout,
		 "Default timeout in seconds for initialization and EH commands. "
		 "[Default=" __stringify(IBMVFC_DEFAULT_TIMEOUT) "]");
module_param_named(max_requests, max_requests, uint, S_IRUGO);
MODULE_PARM_DESC(max_requests, "Maximum requests for this adapter. "
		 "[Default=" __stringify(IBMVFC_MAX_REQUESTS_DEFAULT) "]");
module_param_named(max_lun, max_lun, uint, S_IRUGO);
MODULE_PARM_DESC(max_lun, "Maximum allowed LUN. "
		 "[Default=" __stringify(IBMVFC_MAX_LUN) "]");
module_param_named(max_targets, max_targets, uint, S_IRUGO);
MODULE_PARM_DESC(max_targets, "Maximum allowed targets. "
		 "[Default=" __stringify(IBMVFC_MAX_TARGETS) "]");
module_param_named(disc_threads, disc_threads, uint, S_IRUGO);
MODULE_PARM_DESC(disc_threads, "Number of device discovery threads to use. "
		 "[Default=" __stringify(IBMVFC_MAX_DISC_THREADS) "]");
module_param_named(debug, ibmvfc_debug, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable driver debug information. "
		 "[Default=" __stringify(IBMVFC_DEBUG) "]");
module_param_named(dev_loss_tmo, dev_loss_tmo, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dev_loss_tmo, "Maximum number of seconds that the FC "
		 "transport should insulate the loss of a remote port. Once this "
		 "value is exceeded, the scsi target is removed. "
		 "[Default=" __stringify(IBMVFC_DEV_LOSS_TMO) "]");
module_param_named(log_level, log_level, uint, 0);
MODULE_PARM_DESC(log_level, "Set to 0 - 4 for increasing verbosity of device driver. "
		 "[Default=" __stringify(IBMVFC_DEFAULT_LOG_LEVEL) "]");

static const struct {
	u16 status;
	u16 error;
	u8 result;
	u8 retry;
	int log;
	char *name;
} cmd_status [] = {
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_UNABLE_TO_ESTABLISH, DID_ERROR, 1, 1, "unable to establish" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_XPORT_FAULT, DID_OK, 1, 0, "transport fault" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_CMD_TIMEOUT, DID_TIME_OUT, 1, 1, "command timeout" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_ENETDOWN, DID_TRANSPORT_DISRUPTED, 1, 1, "network down" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_HW_FAILURE, DID_ERROR, 1, 1, "hardware failure" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_LINK_DOWN_ERR, DID_REQUEUE, 0, 0, "link down" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_LINK_DEAD_ERR, DID_ERROR, 0, 0, "link dead" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_UNABLE_TO_REGISTER, DID_ERROR, 1, 1, "unable to register" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_XPORT_BUSY, DID_BUS_BUSY, 1, 0, "transport busy" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_XPORT_DEAD, DID_ERROR, 0, 1, "transport dead" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_CONFIG_ERROR, DID_ERROR, 1, 1, "configuration error" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_NAME_SERVER_FAIL, DID_ERROR, 1, 1, "name server failure" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_LINK_HALTED, DID_REQUEUE, 0, 0, "link halted" },
	{ IBMVFC_FABRIC_MAPPED, IBMVFC_XPORT_GENERAL, DID_OK, 1, 0, "general transport error" },

	{ IBMVFC_VIOS_FAILURE, IBMVFC_CRQ_FAILURE, DID_REQUEUE, 1, 1, "CRQ failure" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_SW_FAILURE, DID_ERROR, 0, 1, "software failure" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_INVALID_PARAMETER, DID_ERROR, 0, 1, "invalid parameter" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_MISSING_PARAMETER, DID_ERROR, 0, 1, "missing parameter" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_HOST_IO_BUS, DID_ERROR, 1, 1, "host I/O bus failure" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_TRANS_CANCELLED, DID_ERROR, 0, 1, "transaction cancelled" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_TRANS_CANCELLED_IMPLICIT, DID_ERROR, 0, 1, "transaction cancelled implicit" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_INSUFFICIENT_RESOURCE, DID_REQUEUE, 1, 1, "insufficient resources" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_PLOGI_REQUIRED, DID_ERROR, 0, 1, "port login required" },
	{ IBMVFC_VIOS_FAILURE, IBMVFC_COMMAND_FAILED, DID_ERROR, 1, 1, "command failed" },

	{ IBMVFC_FC_FAILURE, IBMVFC_INVALID_ELS_CMD_CODE, DID_ERROR, 0, 1, "invalid ELS command code" },
	{ IBMVFC_FC_FAILURE, IBMVFC_INVALID_VERSION, DID_ERROR, 0, 1, "invalid version level" },
	{ IBMVFC_FC_FAILURE, IBMVFC_LOGICAL_ERROR, DID_ERROR, 1, 1, "logical error" },
	{ IBMVFC_FC_FAILURE, IBMVFC_INVALID_CT_IU_SIZE, DID_ERROR, 0, 1, "invalid CT_IU size" },
	{ IBMVFC_FC_FAILURE, IBMVFC_LOGICAL_BUSY, DID_REQUEUE, 1, 0, "logical busy" },
	{ IBMVFC_FC_FAILURE, IBMVFC_PROTOCOL_ERROR, DID_ERROR, 1, 1, "protocol error" },
	{ IBMVFC_FC_FAILURE, IBMVFC_UNABLE_TO_PERFORM_REQ, DID_ERROR, 1, 1, "unable to perform request" },
	{ IBMVFC_FC_FAILURE, IBMVFC_CMD_NOT_SUPPORTED, DID_ERROR, 0, 0, "command not supported" },
	{ IBMVFC_FC_FAILURE, IBMVFC_SERVER_NOT_AVAIL, DID_ERROR, 0, 1, "server not available" },
	{ IBMVFC_FC_FAILURE, IBMVFC_CMD_IN_PROGRESS, DID_ERROR, 0, 1, "command already in progress" },
	{ IBMVFC_FC_FAILURE, IBMVFC_VENDOR_SPECIFIC, DID_ERROR, 1, 1, "vendor specific" },

	{ IBMVFC_FC_SCSI_ERROR, 0, DID_OK, 1, 0, "SCSI error" },
};

static void ibmvfc_npiv_login(struct ibmvfc_host *);
static void ibmvfc_tgt_send_prli(struct ibmvfc_target *);
static void ibmvfc_tgt_send_plogi(struct ibmvfc_target *);
static void ibmvfc_tgt_query_target(struct ibmvfc_target *);

static const char *unknown_error = "unknown error";

#ifdef CONFIG_SCSI_IBMVFC_TRACE
/**
 * ibmvfc_trc_start - Log a start trace entry
 * @evt:		ibmvfc event struct
 *
 **/
static void ibmvfc_trc_start(struct ibmvfc_event *evt)
{
	struct ibmvfc_host *vhost = evt->vhost;
	struct ibmvfc_cmd *vfc_cmd = &evt->iu.cmd;
	struct ibmvfc_mad_common *mad = &evt->iu.mad_common;
	struct ibmvfc_trace_entry *entry;

	entry = &vhost->trace[vhost->trace_index++];
	entry->evt = evt;
	entry->time = jiffies;
	entry->fmt = evt->crq.format;
	entry->type = IBMVFC_TRC_START;

	switch (entry->fmt) {
	case IBMVFC_CMD_FORMAT:
		entry->op_code = vfc_cmd->iu.cdb[0];
		entry->scsi_id = vfc_cmd->tgt_scsi_id;
		entry->lun = scsilun_to_int(&vfc_cmd->iu.lun);
		entry->tmf_flags = vfc_cmd->iu.tmf_flags;
		entry->u.start.xfer_len = vfc_cmd->iu.xfer_len;
		break;
	case IBMVFC_MAD_FORMAT:
		entry->op_code = mad->opcode;
		break;
	default:
		break;
	};
}

/**
 * ibmvfc_trc_end - Log an end trace entry
 * @evt:		ibmvfc event struct
 *
 **/
static void ibmvfc_trc_end(struct ibmvfc_event *evt)
{
	struct ibmvfc_host *vhost = evt->vhost;
	struct ibmvfc_cmd *vfc_cmd = &evt->xfer_iu->cmd;
	struct ibmvfc_mad_common *mad = &evt->xfer_iu->mad_common;
	struct ibmvfc_trace_entry *entry = &vhost->trace[vhost->trace_index++];

	entry->evt = evt;
	entry->time = jiffies;
	entry->fmt = evt->crq.format;
	entry->type = IBMVFC_TRC_END;

	switch (entry->fmt) {
	case IBMVFC_CMD_FORMAT:
		entry->op_code = vfc_cmd->iu.cdb[0];
		entry->scsi_id = vfc_cmd->tgt_scsi_id;
		entry->lun = scsilun_to_int(&vfc_cmd->iu.lun);
		entry->tmf_flags = vfc_cmd->iu.tmf_flags;
		entry->u.end.status = vfc_cmd->status;
		entry->u.end.error = vfc_cmd->error;
		entry->u.end.fcp_rsp_flags = vfc_cmd->rsp.flags;
		entry->u.end.rsp_code = vfc_cmd->rsp.data.info.rsp_code;
		entry->u.end.scsi_status = vfc_cmd->rsp.scsi_status;
		break;
	case IBMVFC_MAD_FORMAT:
		entry->op_code = mad->opcode;
		entry->u.end.status = mad->status;
		break;
	default:
		break;

	};
}

#else
#define ibmvfc_trc_start(evt) do { } while (0)
#define ibmvfc_trc_end(evt) do { } while (0)
#endif

/**
 * ibmvfc_get_err_index - Find the index into cmd_status for the fcp response
 * @status:		status / error class
 * @error:		error
 *
 * Return value:
 *	index into cmd_status / -EINVAL on failure
 **/
static int ibmvfc_get_err_index(u16 status, u16 error)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(cmd_status); i++)
		if ((cmd_status[i].status & status) == cmd_status[i].status &&
		    cmd_status[i].error == error)
			return i;

	return -EINVAL;
}

/**
 * ibmvfc_get_cmd_error - Find the error description for the fcp response
 * @status:		status / error class
 * @error:		error
 *
 * Return value:
 *	error description string
 **/
static const char *ibmvfc_get_cmd_error(u16 status, u16 error)
{
	int rc = ibmvfc_get_err_index(status, error);
	if (rc >= 0)
		return cmd_status[rc].name;
	return unknown_error;
}

/**
 * ibmvfc_get_err_result - Find the scsi status to return for the fcp response
 * @vfc_cmd:	ibmvfc command struct
 *
 * Return value:
 *	SCSI result value to return for completed command
 **/
static int ibmvfc_get_err_result(struct ibmvfc_cmd *vfc_cmd)
{
	int err;
	struct ibmvfc_fcp_rsp *rsp = &vfc_cmd->rsp;
	int fc_rsp_len = rsp->fcp_rsp_len;

	if ((rsp->flags & FCP_RSP_LEN_VALID) &&
	    ((!fc_rsp_len && fc_rsp_len != 4 && fc_rsp_len != 8) ||
	     rsp->data.info.rsp_code))
		return DID_ERROR << 16;

	err = ibmvfc_get_err_index(vfc_cmd->status, vfc_cmd->error);
	if (err >= 0)
		return rsp->scsi_status | (cmd_status[err].result << 16);
	return rsp->scsi_status | (DID_ERROR << 16);
}

/**
 * ibmvfc_retry_cmd - Determine if error status is retryable
 * @status:		status / error class
 * @error:		error
 *
 * Return value:
 *	1 if error should be retried / 0 if it should not
 **/
static int ibmvfc_retry_cmd(u16 status, u16 error)
{
	int rc = ibmvfc_get_err_index(status, error);

	if (rc >= 0)
		return cmd_status[rc].retry;
	return 1;
}

static const char *unknown_fc_explain = "unknown fc explain";

static const struct {
	u16 fc_explain;
	char *name;
} ls_explain [] = {
	{ 0x00, "no additional explanation" },
	{ 0x01, "service parameter error - options" },
	{ 0x03, "service parameter error - initiator control" },
	{ 0x05, "service parameter error - recipient control" },
	{ 0x07, "service parameter error - received data field size" },
	{ 0x09, "service parameter error - concurrent seq" },
	{ 0x0B, "service parameter error - credit" },
	{ 0x0D, "invalid N_Port/F_Port_Name" },
	{ 0x0E, "invalid node/Fabric Name" },
	{ 0x0F, "invalid common service parameters" },
	{ 0x11, "invalid association header" },
	{ 0x13, "association header required" },
	{ 0x15, "invalid originator S_ID" },
	{ 0x17, "invalid OX_ID-RX-ID combination" },
	{ 0x19, "command (request) already in progress" },
	{ 0x1E, "N_Port Login requested" },
	{ 0x1F, "Invalid N_Port_ID" },
};

static const struct {
	u16 fc_explain;
	char *name;
} gs_explain [] = {
	{ 0x00, "no additional explanation" },
	{ 0x01, "port identifier not registered" },
	{ 0x02, "port name not registered" },
	{ 0x03, "node name not registered" },
	{ 0x04, "class of service not registered" },
	{ 0x06, "initial process associator not registered" },
	{ 0x07, "FC-4 TYPEs not registered" },
	{ 0x08, "symbolic port name not registered" },
	{ 0x09, "symbolic node name not registered" },
	{ 0x0A, "port type not registered" },
	{ 0xF0, "authorization exception" },
	{ 0xF1, "authentication exception" },
	{ 0xF2, "data base full" },
	{ 0xF3, "data base empty" },
	{ 0xF4, "processing request" },
	{ 0xF5, "unable to verify connection" },
	{ 0xF6, "devices not in a common zone" },
};

/**
 * ibmvfc_get_ls_explain - Return the FC Explain description text
 * @status:	FC Explain status
 *
 * Returns:
 *	error string
 **/
static const char *ibmvfc_get_ls_explain(u16 status)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(ls_explain); i++)
		if (ls_explain[i].fc_explain == status)
			return ls_explain[i].name;

	return unknown_fc_explain;
}

/**
 * ibmvfc_get_gs_explain - Return the FC Explain description text
 * @status:	FC Explain status
 *
 * Returns:
 *	error string
 **/
static const char *ibmvfc_get_gs_explain(u16 status)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(gs_explain); i++)
		if (gs_explain[i].fc_explain == status)
			return gs_explain[i].name;

	return unknown_fc_explain;
}

static const struct {
	enum ibmvfc_fc_type fc_type;
	char *name;
} fc_type [] = {
	{ IBMVFC_FABRIC_REJECT, "fabric reject" },
	{ IBMVFC_PORT_REJECT, "port reject" },
	{ IBMVFC_LS_REJECT, "ELS reject" },
	{ IBMVFC_FABRIC_BUSY, "fabric busy" },
	{ IBMVFC_PORT_BUSY, "port busy" },
	{ IBMVFC_BASIC_REJECT, "basic reject" },
};

static const char *unknown_fc_type = "unknown fc type";

/**
 * ibmvfc_get_fc_type - Return the FC Type description text
 * @status:	FC Type error status
 *
 * Returns:
 *	error string
 **/
static const char *ibmvfc_get_fc_type(u16 status)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(fc_type); i++)
		if (fc_type[i].fc_type == status)
			return fc_type[i].name;

	return unknown_fc_type;
}

/**
 * ibmvfc_set_tgt_action - Set the next init action for the target
 * @tgt:		ibmvfc target struct
 * @action:		action to perform
 *
 **/
static void ibmvfc_set_tgt_action(struct ibmvfc_target *tgt,
				  enum ibmvfc_target_action action)
{
	switch (tgt->action) {
	case IBMVFC_TGT_ACTION_DEL_RPORT:
		break;
	default:
		tgt->action = action;
		break;
	}
}

/**
 * ibmvfc_set_host_state - Set the state for the host
 * @vhost:		ibmvfc host struct
 * @state:		state to set host to
 *
 * Returns:
 *	0 if state changed / non-zero if not changed
 **/
static int ibmvfc_set_host_state(struct ibmvfc_host *vhost,
				  enum ibmvfc_host_state state)
{
	int rc = 0;

	switch (vhost->state) {
	case IBMVFC_HOST_OFFLINE:
		rc = -EINVAL;
		break;
	default:
		vhost->state = state;
		break;
	};

	return rc;
}

/**
 * ibmvfc_set_host_action - Set the next init action for the host
 * @vhost:		ibmvfc host struct
 * @action:		action to perform
 *
 **/
static void ibmvfc_set_host_action(struct ibmvfc_host *vhost,
				   enum ibmvfc_host_action action)
{
	switch (action) {
	case IBMVFC_HOST_ACTION_ALLOC_TGTS:
		if (vhost->action == IBMVFC_HOST_ACTION_INIT_WAIT)
			vhost->action = action;
		break;
	case IBMVFC_HOST_ACTION_INIT_WAIT:
		if (vhost->action == IBMVFC_HOST_ACTION_INIT)
			vhost->action = action;
		break;
	case IBMVFC_HOST_ACTION_QUERY:
		switch (vhost->action) {
		case IBMVFC_HOST_ACTION_INIT_WAIT:
		case IBMVFC_HOST_ACTION_NONE:
		case IBMVFC_HOST_ACTION_TGT_ADD:
			vhost->action = action;
			break;
		default:
			break;
		};
		break;
	case IBMVFC_HOST_ACTION_TGT_INIT:
		if (vhost->action == IBMVFC_HOST_ACTION_ALLOC_TGTS)
			vhost->action = action;
		break;
	case IBMVFC_HOST_ACTION_INIT:
	case IBMVFC_HOST_ACTION_TGT_DEL:
	case IBMVFC_HOST_ACTION_QUERY_TGTS:
	case IBMVFC_HOST_ACTION_TGT_DEL_FAILED:
	case IBMVFC_HOST_ACTION_TGT_ADD:
	case IBMVFC_HOST_ACTION_NONE:
	default:
		vhost->action = action;
		break;
	};
}

/**
 * ibmvfc_reinit_host - Re-start host initialization (no NPIV Login)
 * @vhost:		ibmvfc host struct
 *
 * Return value:
 *	nothing
 **/
static void ibmvfc_reinit_host(struct ibmvfc_host *vhost)
{
	if (vhost->action == IBMVFC_HOST_ACTION_NONE) {
		if (!ibmvfc_set_host_state(vhost, IBMVFC_INITIALIZING)) {
			scsi_block_requests(vhost->host);
			ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_QUERY);
		}
	} else
		vhost->reinit = 1;

	wake_up(&vhost->work_wait_q);
}

/**
 * ibmvfc_link_down - Handle a link down event from the adapter
 * @vhost:	ibmvfc host struct
 * @state:	ibmvfc host state to enter
 *
 **/
static void ibmvfc_link_down(struct ibmvfc_host *vhost,
			     enum ibmvfc_host_state state)
{
	struct ibmvfc_target *tgt;

	ENTER;
	scsi_block_requests(vhost->host);
	list_for_each_entry(tgt, &vhost->targets, queue)
		ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_DEL_RPORT);
	ibmvfc_set_host_state(vhost, state);
	ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_TGT_DEL);
	vhost->events_to_log |= IBMVFC_AE_LINKDOWN;
	wake_up(&vhost->work_wait_q);
	LEAVE;
}

/**
 * ibmvfc_init_host - Start host initialization
 * @vhost:		ibmvfc host struct
 * @relogin:	is this a re-login?
 *
 * Return value:
 *	nothing
 **/
static void ibmvfc_init_host(struct ibmvfc_host *vhost, int relogin)
{
	struct ibmvfc_target *tgt;

	if (vhost->action == IBMVFC_HOST_ACTION_INIT_WAIT) {
		if (++vhost->init_retries > IBMVFC_MAX_HOST_INIT_RETRIES) {
			dev_err(vhost->dev,
				"Host initialization retries exceeded. Taking adapter offline\n");
			ibmvfc_link_down(vhost, IBMVFC_HOST_OFFLINE);
			return;
		}
	}

	if (!ibmvfc_set_host_state(vhost, IBMVFC_INITIALIZING)) {
		if (!relogin) {
			memset(vhost->async_crq.msgs, 0, PAGE_SIZE);
			vhost->async_crq.cur = 0;
		}

		list_for_each_entry(tgt, &vhost->targets, queue)
			tgt->need_login = 1;
		scsi_block_requests(vhost->host);
		ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_INIT);
		vhost->job_step = ibmvfc_npiv_login;
		wake_up(&vhost->work_wait_q);
	}
}

/**
 * ibmvfc_send_crq - Send a CRQ
 * @vhost:	ibmvfc host struct
 * @word1:	the first 64 bits of the data
 * @word2:	the second 64 bits of the data
 *
 * Return value:
 *	0 on success / other on failure
 **/
static int ibmvfc_send_crq(struct ibmvfc_host *vhost, u64 word1, u64 word2)
{
	struct vio_dev *vdev = to_vio_dev(vhost->dev);
	return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
}

/**
 * ibmvfc_send_crq_init - Send a CRQ init message
 * @vhost:	ibmvfc host struct
 *
 * Return value:
 *	0 on success / other on failure
 **/
static int ibmvfc_send_crq_init(struct ibmvfc_host *vhost)
{
	ibmvfc_dbg(vhost, "Sending CRQ init\n");
	return ibmvfc_send_crq(vhost, 0xC001000000000000LL, 0);
}

/**
 * ibmvfc_send_crq_init_complete - Send a CRQ init complete message
 * @vhost:	ibmvfc host struct
 *
 * Return value:
 *	0 on success / other on failure
 **/
static int ibmvfc_send_crq_init_complete(struct ibmvfc_host *vhost)
{
	ibmvfc_dbg(vhost, "Sending CRQ init complete\n");
	return ibmvfc_send_crq(vhost, 0xC002000000000000LL, 0);
}

/**
 * ibmvfc_release_crq_queue - Deallocates data and unregisters CRQ
 * @vhost:	ibmvfc host struct
 *
 * Frees irq, deallocates a page for messages, unmaps dma, and unregisters
 * the crq with the hypervisor.
 **/
static void ibmvfc_release_crq_queue(struct ibmvfc_host *vhost)
{
	long rc;
	struct vio_dev *vdev = to_vio_dev(vhost->dev);
	struct ibmvfc_crq_queue *crq = &vhost->crq;

	ibmvfc_dbg(vhost, "Releasing CRQ\n");
	free_irq(vdev->irq, vhost);
	tasklet_kill(&vhost->tasklet);
	do {
		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));

	vhost->state = IBMVFC_NO_CRQ;
	dma_unmap_single(vhost->dev, crq->msg_token, PAGE_SIZE, DMA_BIDIRECTIONAL);
	free_page((unsigned long)crq->msgs);
}

/**
 * ibmvfc_reenable_crq_queue - reenables the CRQ
 * @vhost:	ibmvfc host struct
 *
 * Return value:
 *	0 on success / other on failure
 **/
static int ibmvfc_reenable_crq_queue(struct ibmvfc_host *vhost)
{
	int rc;
	struct vio_dev *vdev = to_vio_dev(vhost->dev);

	/* Re-enable the CRQ */
	do {
		rc = plpar_hcall_norets(H_ENABLE_CRQ, vdev->unit_address);
	} while (rc == H_IN_PROGRESS || rc == H_BUSY || H_IS_LONG_BUSY(rc));

	if (rc)
		dev_err(vhost->dev, "Error enabling adapter (rc=%d)\n", rc);

	return rc;
}

/**
 * ibmvfc_reset_crq - resets a crq after a failure
 * @vhost:	ibmvfc host struct
 *
 * Return value:
 *	0 on success / other on failure
 **/
static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
{
	int rc;
	struct vio_dev *vdev = to_vio_dev(vhost->dev);
	struct ibmvfc_crq_queue *crq = &vhost->crq;

	/* Close the CRQ */
	do {
		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));

	vhost->state = IBMVFC_NO_CRQ;
	ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_NONE);

	/* Clean out the queue */
	memset(crq->msgs, 0, PAGE_SIZE);
	crq->cur = 0;

	/* And re-open it again */
	rc = plpar_hcall_norets(H_REG_CRQ, vdev->unit_address,
				crq->msg_token, PAGE_SIZE);

	if (rc == H_CLOSED)
		/* Adapter is good, but other end is not ready */
		dev_warn(vhost->dev, "Partner adapter not ready\n");
	else if (rc != 0)
		dev_warn(vhost->dev, "Couldn't register crq (rc=%d)\n", rc);

	return rc;
}

/**
 * ibmvfc_valid_event - Determines if event is valid.
 * @pool:	event_pool that contains the event
 * @evt:	ibmvfc event to be checked for validity
 *
 * Return value:
 *	1 if event is valid / 0 if event is not valid
 **/
static int ibmvfc_valid_event(struct ibmvfc_event_pool *pool,
			      struct ibmvfc_event *evt)
{
	int index = evt - pool->events;
	if (index < 0 || index >= pool->size)	/* outside of bounds */
		return 0;
	if (evt != pool->events + index)	/* unaligned */
		return 0;
	return 1;
}

/**
 * ibmvfc_free_event - Free the specified event
 * @evt:	ibmvfc_event to be freed
 *
 **/
static void ibmvfc_free_event(struct ibmvfc_event *evt)
{
	struct ibmvfc_host *vhost = evt->vhost;
	struct ibmvfc_event_pool *pool = &vhost->pool;

	BUG_ON(!ibmvfc_valid_event(pool, evt));
	BUG_ON(atomic_inc_return(&evt->free) != 1);
	list_add_tail(&evt->queue, &vhost->free);
}

/**
 * ibmvfc_scsi_eh_done - EH done function for queuecommand commands
 * @evt:	ibmvfc event struct
 *
 * This function does not setup any error status, that must be done
 * before this function gets called.
 **/
static void ibmvfc_scsi_eh_done(struct ibmvfc_event *evt)
{
	struct scsi_cmnd *cmnd = evt->cmnd;

	if (cmnd) {
		scsi_dma_unmap(cmnd);
		cmnd->scsi_done(cmnd);
	}

	if (evt->eh_comp)
		complete(evt->eh_comp);

	ibmvfc_free_event(evt);
}

/**
 * ibmvfc_fail_request - Fail request with specified error code
 * @evt:		ibmvfc event struct
 * @error_code:	error code to fail request with
 *
 * Return value:
 *	none
 **/
static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code)
{
	if (evt->cmnd) {
		evt->cmnd->result = (error_code << 16);
		evt->done = ibmvfc_scsi_eh_done;
	} else
		evt->xfer_iu->mad_common.status = IBMVFC_MAD_DRIVER_FAILED;

	list_del(&evt->queue);
	del_timer(&evt->timer);
	ibmvfc_trc_end(evt);
	evt->done(evt);
}

/**
 * ibmvfc_purge_requests - Our virtual adapter just shut down. Purge any sent requests
 * @vhost:		ibmvfc host struct
 * @error_code:	error code to fail requests with
 *
 * Return value:
 *	none
 **/
static void ibmvfc_purge_requests(struct ibmvfc_host *vhost, int error_code)
{
	struct ibmvfc_event *evt, *pos;

	ibmvfc_dbg(vhost, "Purging all requests\n");
	list_for_each_entry_safe(evt, pos, &vhost->sent, queue)
		ibmvfc_fail_request(evt, error_code);
}

/**
 * __ibmvfc_reset_host - Reset the connection to the server (no locking)
 * @vhost:	struct ibmvfc host to reset
 **/
static void __ibmvfc_reset_host(struct ibmvfc_host *vhost)
{
	int rc;

	scsi_block_requests(vhost->host);
	ibmvfc_purge_requests(vhost, DID_ERROR);
	if ((rc = ibmvfc_reset_crq(vhost)) ||
	    (rc = ibmvfc_send_crq_init(vhost)) ||
	    (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {
		dev_err(vhost->dev, "Error after reset rc=%d\n", rc);
		ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
	} else
		ibmvfc_link_down(vhost, IBMVFC_LINK_DOWN);
}

/**
 * ibmvfc_reset_host - Reset the connection to the server
 * @vhost:	struct ibmvfc host to reset
 **/
static void ibmvfc_reset_host(struct ibmvfc_host *vhost)
{
	unsigned long flags;

	spin_lock_irqsave(vhost->host->host_lock, flags);
	__ibmvfc_reset_host(vhost);
	spin_unlock_irqrestore(vhost->host->host_lock, flags);
}

/**
 * ibmvfc_retry_host_init - Retry host initialization if allowed
 * @vhost:	ibmvfc host struct
 *
 **/
static void ibmvfc_retry_host_init(struct ibmvfc_host *vhost)
{
	if (vhost->action == IBMVFC_HOST_ACTION_INIT_WAIT) {
		vhost->delay_init = 1;
		if (++vhost->init_retries > IBMVFC_MAX_HOST_INIT_RETRIES) {
			dev_err(vhost->dev,
				"Host initialization retries exceeded. Taking adapter offline\n");
			ibmvfc_link_down(vhost, IBMVFC_HOST_OFFLINE);
		} else if (vhost->init_retries == IBMVFC_MAX_HOST_INIT_RETRIES)
			__ibmvfc_reset_host(vhost);
		else
			ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_INIT);
	}

	wake_up(&vhost->work_wait_q);
}

/**
 * __ibmvfc_get_target - Find the specified scsi_target (no locking)
 * @starget:	scsi target struct
 *
 * Return value:
 *	ibmvfc_target struct / NULL if not found
 **/
static struct ibmvfc_target *__ibmvfc_get_target(struct scsi_target *starget)
{
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct ibmvfc_host *vhost = shost_priv(shost);
	struct ibmvfc_target *tgt;

	list_for_each_entry(tgt, &vhost->targets, queue)
		if (tgt->target_id == starget->id) {
			kref_get(&tgt->kref);
			return tgt;
		}
	return NULL;
}

/**
 * ibmvfc_get_target - Find the specified scsi_target
 * @starget:	scsi target struct
 *
 * Return value:
 *	ibmvfc_target struct / NULL if not found
 **/
static struct ibmvfc_target *ibmvfc_get_target(struct scsi_target *starget)
{
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct ibmvfc_target *tgt;
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);
	tgt = __ibmvfc_get_target(starget);
	spin_unlock_irqrestore(shost->host_lock, flags);
	return tgt;
}

/**
 * ibmvfc_get_host_speed - Get host port speed
 * @shost:		scsi host struct
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_get_host_speed(struct Scsi_Host *shost)
{
	struct ibmvfc_host *vhost = shost_priv(shost);
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);
	if (vhost->state == IBMVFC_ACTIVE) {
		switch (vhost->login_buf->resp.link_speed / 100) {
		case 1:
			fc_host_speed(shost) = FC_PORTSPEED_1GBIT;
			break;
		case 2:
			fc_host_speed(shost) = FC_PORTSPEED_2GBIT;
			break;
		case 4:
			fc_host_speed(shost) = FC_PORTSPEED_4GBIT;
			break;
		case 8:
			fc_host_speed(shost) = FC_PORTSPEED_8GBIT;
			break;
		case 10:
			fc_host_speed(shost) = FC_PORTSPEED_10GBIT;
			break;
		case 16:
			fc_host_speed(shost) = FC_PORTSPEED_16GBIT;
			break;
		default:
			ibmvfc_log(vhost, 3, "Unknown port speed: %lld Gbit\n",
				   vhost->login_buf->resp.link_speed / 100);
			fc_host_speed(shost) = FC_PORTSPEED_UNKNOWN;
			break;
		}
	} else
		fc_host_speed(shost) = FC_PORTSPEED_UNKNOWN;
	spin_unlock_irqrestore(shost->host_lock, flags);
}

/**
 * ibmvfc_get_host_port_state - Get host port state
 * @shost:		scsi host struct
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_get_host_port_state(struct Scsi_Host *shost)
{
	struct ibmvfc_host *vhost = shost_priv(shost);
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);
	switch (vhost->state) {
	case IBMVFC_INITIALIZING:
	case IBMVFC_ACTIVE:
		fc_host_port_state(shost) = FC_PORTSTATE_ONLINE;
		break;
	case IBMVFC_LINK_DOWN:
		fc_host_port_state(shost) = FC_PORTSTATE_LINKDOWN;
		break;
	case IBMVFC_LINK_DEAD:
	case IBMVFC_HOST_OFFLINE:
		fc_host_port_state(shost) = FC_PORTSTATE_OFFLINE;
		break;
	case IBMVFC_HALTED:
		fc_host_port_state(shost) = FC_PORTSTATE_BLOCKED;
		break;
	case IBMVFC_NO_CRQ:
		fc_host_port_state(shost) = FC_PORTSTATE_UNKNOWN;
		break;
	default:
		ibmvfc_log(vhost, 3, "Unknown port state: %d\n", vhost->state);
		fc_host_port_state(shost) = FC_PORTSTATE_UNKNOWN;
		break;
	}
	spin_unlock_irqrestore(shost->host_lock, flags);
}

/**
 * ibmvfc_set_rport_dev_loss_tmo - Set rport's device loss timeout
 * @rport:		rport struct
 * @timeout:	timeout value
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_set_rport_dev_loss_tmo(struct fc_rport *rport, u32 timeout)
{
	if (timeout)
		rport->dev_loss_tmo = timeout;
	else
		rport->dev_loss_tmo = 1;
}

/**
 * ibmvfc_release_tgt - Free memory allocated for a target
 * @kref:		kref struct
 *
 **/
static void ibmvfc_release_tgt(struct kref *kref)
{
	struct ibmvfc_target *tgt = container_of(kref, struct ibmvfc_target, kref);
	kfree(tgt);
}

/**
 * ibmvfc_get_starget_node_name - Get SCSI target's node name
 * @starget:	scsi target struct
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_get_starget_node_name(struct scsi_target *starget)
{
	struct ibmvfc_target *tgt = ibmvfc_get_target(starget);
	fc_starget_port_name(starget) = tgt ? tgt->ids.node_name : 0;
	if (tgt)
		kref_put(&tgt->kref, ibmvfc_release_tgt);
}

/**
 * ibmvfc_get_starget_port_name - Get SCSI target's port name
 * @starget:	scsi target struct
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_get_starget_port_name(struct scsi_target *starget)
{
	struct ibmvfc_target *tgt = ibmvfc_get_target(starget);
	fc_starget_port_name(starget) = tgt ? tgt->ids.port_name : 0;
	if (tgt)
		kref_put(&tgt->kref, ibmvfc_release_tgt);
}

/**
 * ibmvfc_get_starget_port_id - Get SCSI target's port ID
 * @starget:	scsi target struct
 *
 * Return value:
 * 	none
 **/
static void ibmvfc_get_starget_port_id(struct scsi_target *starget)
{
	struct ibmvfc_target *tgt = ibmvfc_get_target(starget);
	fc_starget_port_id(starget) = tgt ? tgt->scsi_id : -1;
	if (tgt)
		kref_put(&tgt->kref, ibmvfc_release_tgt);
}

/**
 * ibmvfc_wait_while_resetting - Wait while the host resets
 * @vhost:		ibmvfc host struct
 *
 * Return value:
 * 	0 on success / other on failure
 **/
static int ibmvfc_wait_while_resetting(struct ibmvfc_host *vhost)
{
	long timeout = wait_event_timeout(vhost->init_wait_q,
					  ((vhost->state == IBMVFC_ACTIVE ||
					    vhost->state == IBMVFC_HOST_OFFLINE ||
					    vhost->state == IBMVFC_LINK_DEAD) &&
					   vhost->action == IBMVFC_HOST_ACTION_NONE),
					  (init_timeout * HZ));

	return timeout ? 0 : -EIO;
}

/**
 * ibmvfc_issue_fc_host_lip - Re-initiate link initialization
 * @shost:		scsi host struct
 *
 * Return value:
 * 	0 on success / other on failure
 **/
static int ibmvfc_issue_fc_host_lip(struct Scsi_Host *shost)
{
	struct ibmvfc_host *vhost = shost_priv(shost);

	dev_err(vhost->dev, "Initiating host LIP. Resetting connection\n");
	ibmvfc_reset_host(vhost);
	return ibmvfc_wait_while_resetting(vhost);
}

/**
 * ibmvfc_gather_partition_info - Gather info about the LPAR
 *
 * Return value:
 *	none
 **/
static void ibmvfc_gather_partition_info(struct ibmvfc_host *vhost)
{
	struct device_node *rootdn;
	const char *name;
	const unsigned int *num;

	rootdn = of_find_node_by_path("/");
	if (!rootdn)
		return;

	name = of_get_property(rootdn, "ibm,partition-name", NULL);
	if (name)
		strncpy(vhost->partition_name, name, sizeof(vhost->partition_name));
	num = of_get_property(rootdn, "ibm,partition-no", NULL);
	if (num)
		vhost->partition_number = *num;
	of_node_put(rootdn);
}

/**
 * ibmvfc_set_login_info - Setup info for NPIV login
 * @vhost:	ibmvfc host struct
 *
 * Return value:
 *	none
 **/
static void ibmvfc_set_login_info(struct ibmvfc_host *vhost)
{
	struct ibmvfc_npiv_login *login_info = &vhost->login_info;
	struct device_node *of_node = vhost->dev->archdata.of_node;
	const char *location;

	memset(login_info, 0, sizeof(*login_info));

	login_info->ostype = IBMVFC_OS_LINUX;
	login_info->max_dma_len = IBMVFC_MAX_SECTORS << 9;
	login_info->max_payload = sizeof(struct ibmvfc_fcp_cmd_iu);
	login_info->max_response = sizeof(struct ibmvfc_fcp_rsp);
	login_info->partition_num = vhost->partition_number;
	login_info->vfc_frame_version = 1;
	login_info->fcp_version = 3;
	if (vhost->client_migrated)
		login_info->flags = IBMVFC_CLIENT_MIGRATED;

	login_info->max_cmds = max_requests + IBMVFC_NUM_INTERNAL_REQ;
	login_info->capabilities = IBMVFC_CAN_MIGRATE;
	login_info->async.va = vhost->async_crq.msg_token;
	login_info->async.len = vhost->async_crq.size * sizeof(*vhost->async_crq.msgs);
	strncpy(login_info->partition_name, vhost->partition_name, IBMVFC_MAX_NAME);
	strncpy(login_info->device_name,
		dev_name(&vhost->host->shost_gendev), IBMVFC_MAX_NAME);

	location = of_get_property(of_node, "ibm,loc-code", NULL);
	location = location ? location : dev_name(vhost->dev);
	strncpy(login_info->drc_name, location, IBMVFC_MAX_NAME);
}

/**
 * ibmvfc_init_event_pool - Allocates and initializes the event pool for a host
 * @vhost:	ibmvfc host who owns the event pool
 *
 * Returns zero on success.
 **/
static int ibmvfc_init_event_pool(struct ibmvfc_host *vhost)
{
	int i;
	struct ibmvfc_event_pool *pool = &vhost->pool;

	ENTER;
	pool->size = max_requests + IBMVFC_NUM_INTERNAL_REQ;
	pool->events = kcalloc(pool->size, sizeof(*pool->events), GFP_KERNEL);
	if (!pool->events)
		return -ENOMEM;

	pool->iu_storage = dma_alloc_coherent(vhost->dev,
					      pool->size * sizeof(*pool->iu_storage),
					      &pool->iu_token, 0);

	if (!pool->iu_storage) {
		kfree(pool->events);
		return -ENOMEM;
	}

	for (i = 0; i < pool->size; ++i) {
		struct ibmvfc_event *evt = &pool->events[i];
		atomic_set(&evt->free, 1);
		evt->crq.valid = 0x80;
		evt->crq.ioba = pool->iu_token + (sizeof(*evt->xfer_iu) * i);
		evt->xfer_iu = pool->iu_storage + i;
		evt->vhost = vhost;
		evt->ext_list = NULL;
		list_add_tail(&evt->queue, &vhost->free);
	}

	LEAVE;
	return 0;
}

/**
 * ibmvfc_free_event_pool - Frees memory of the event pool of a host
 * @vhost:	ibmvfc host who owns the event pool
 *
 **/
static void ibmvfc_free_event_pool(struct ibmvfc_host *vhost)
{
	int i;
	struct ibmvfc_event_pool *pool = &vhost->pool;

	ENTER;
	for (i = 0; i < pool->size; ++i) {
		list_del(&pool->events[i].queue);
		BUG_ON(atomic_read(&pool->events[i].free) != 1);
		if (pool->events[i].ext_list)
			dma_pool_free(vhost->sg_pool,
				      pool->events[i].ext_list,
				      pool->events[i].ext_list_token);
	}

	kfree(pool->events);
	dma_free_coherent(vhost->dev,
			  pool->size * sizeof(*pool->iu_storage),
			  pool->iu_storage, pool->iu_token);
	LEAVE;
}

/**
 * ibmvfc_get_event - Gets the next free event in pool
 * @vhost:	ibmvfc host struct
 *
 * Returns a free event from the pool.
 **/
static struct ibmvfc_event *ibmvfc_get_event(struct ibmvfc_host *vhost)
{
	struct ibmvfc_event *evt;

	BUG_ON(list_empty(&vhost->free));
	evt = list_entry(vhost->free.next, struct ibmvfc_event, queue);
	atomic_set(&evt->free, 0);
	list_del(&evt->queue);
	return evt;
}

/**
 * ibmvfc_init_event - Initialize fields in an event struct that are always
 *				required.
 * @evt:	The event
 * @done:	Routine to call when the event is responded to
 * @format:	SRP or MAD format
 **/
static void ibmvfc_init_event(struct ibmvfc_event *evt,
			      void (*done) (struct ibmvfc_event *), u8 format)
{
	evt->cmnd = NULL;
	evt->sync_iu = NULL;
	evt->crq.format = format;
	evt->done = done;
	evt->eh_comp = NULL;
}

/**
 * ibmvfc_map_sg_list - Initialize scatterlist
 * @scmd:	scsi command struct
 * @nseg:	number of scatterlist segments
 * @md:	memory descriptor list to initialize
 **/
static void ibmvfc_map_sg_list(struct scsi_cmnd *scmd, int nseg,
			       struct srp_direct_buf *md)
{
	int i;
	struct scatterlist *sg;

	scsi_for_each_sg(scmd, sg, nseg, i) {
		md[i].va = sg_dma_address(sg);
		md[i].len = sg_dma_len(sg);
		md[i].key = 0;
	}
}

/**
 * ibmvfc_map_sg_data - Maps dma for a scatterlist and initializes decriptor fields
 * @scmd:		Scsi_Cmnd with the scatterlist
 * @evt:		ibmvfc event struct
 * @vfc_cmd:	vfc_cmd that contains the memory descriptor
 * @dev:		device for which to map dma memory
 *
 * Returns:
 *	0 on success / non-zero on failure
 **/
static int ibmvfc_map_sg_data(struct scsi_cmnd *scmd,
			      struct ibmvfc_event *evt,
			      struct ibmvfc_cmd *vfc_cmd, struct device *dev)
{

	int sg_mapped;
	struct srp_direct_buf *data = &vfc_cmd->ioba;
	struct ibmvfc_host *vhost = dev_get_drvdata(dev);

	sg_mapped = scsi_dma_map(scmd);
	if (!sg_mapped) {
		vfc_cmd->flags |= IBMVFC_NO_MEM_DESC;
		return 0;
	} else if (unlikely(sg_mapped < 0)) {
		if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
			scmd_printk(KERN_ERR, scmd, "Failed to map DMA buffer for command\n");
		return sg_mapped;
	}

	if (scmd->sc_data_direction == DMA_TO_DEVICE) {
		vfc_cmd->flags |= IBMVFC_WRITE;
		vfc_cmd->iu.add_cdb_len |= IBMVFC_WRDATA;
	} else {
		vfc_cmd->flags |= IBMVFC_READ;
		vfc_cmd->iu.add_cdb_len |= IBMVFC_RDDATA;
	}

	if (sg_mapped == 1) {
		ibmvfc_map_sg_list(scmd, sg_mapped, data);
		return 0;
	}

	vfc_cmd->flags |= IBMVFC_SCATTERLIST;

	if (!evt->ext_list) {
		evt->ext_list = dma_pool_alloc(vhost->sg_pool, GFP_ATOMIC,
					       &evt->ext_list_token);

		if (!evt->ext_list) {
			scsi_dma_unmap(scmd);
			if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
				scmd_printk(KERN_ERR, scmd, "Can't allocate memory for scatterlist\n");
			return -ENOMEM;
		}
	}

	ibmvfc_map_sg_list(scmd, sg_mapped, evt->ext_list);

	data->va = evt->ext_list_token;
	data->len = sg_mapped * sizeof(struct srp_direct_buf);
	data->key = 0;
	return 0;
}

/**
 * ibmvfc_timeout - Internal command timeout handler
 * @evt:	struct ibmvfc_event that timed out
 *
 * Called when an internally generated command times out
 **/
static void ibmvfc_timeout(struct ibmvfc_event *evt)
{
	struct ibmvfc_host *vhost = evt->vhost;
	dev_err(vhost->dev, "Command timed out (%p). Resetting connection\n", evt);
	ibmvfc_reset_host(vhost);
}

/**
 * ibmvfc_send_event - Transforms event to u64 array and calls send_crq()
 * @evt:		event to be sent
 * @vhost:		ibmvfc host struct
 * @timeout:	timeout in seconds - 0 means do not time command
 *
 * Returns the value returned from ibmvfc_send_crq(). (Zero for success)
 **/
static int ibmvfc_send_event(struct ibmvfc_event *evt,
			     struct ibmvfc_host *vhost, unsigned long timeout)
{
	u64 *crq_as_u64 = (u64 *) &evt->crq;
	int rc;

	/* Copy the IU into the transfer area */
	*evt->xfer_iu = evt->iu;
	if (evt->crq.format == IBMVFC_CMD_FORMAT)
		evt->xfer_iu->cmd.tag = (u64)evt;
	else if (evt->crq.format == IBMVFC_MAD_FORMAT)
		evt->xfer_iu->mad_common.tag = (u64)evt;
	else
		BUG();

	list_add_tail(&evt->queue, &vhost->sent);
	init_timer(&evt->timer);

	if (timeout) {
		evt->timer.data = (unsigned long) evt;
		evt->timer.expires = jiffies + (timeout * HZ);
		evt->timer.function = (void (*)(unsigned long))ibmvfc_timeout;
		add_timer(&evt->timer);
	}

	mb();

	if ((rc = ibmvfc_send_crq(vhost, crq_as_u64[0], crq_as_u64[1]))) {
		list_del(&evt->queue);
		del_timer(&evt->timer);

		/* If send_crq returns H_CLOSED, return SCSI_MLQUEUE_HOST_BUSY.
		 * Firmware will send a CRQ with a transport event (0xFF) to
		 * tell this client what has happened to the transport. This
		 * will be handled in ibmvfc_handle_crq()
		 */
		if (rc == H_CLOSED) {
			if (printk_ratelimit())
				dev_warn(vhost->dev, "Send warning. Receive queue closed, will retry.\n");
			if (evt->cmnd)
				scsi_dma_unmap(evt->cmnd);
			ibmvfc_free_event(evt);
			return SCSI_MLQUEUE_HOST_BUSY;
		}

		dev_err(vhost->dev, "Send error (rc=%d)\n", rc);
		if (evt->cmnd) {
			evt->cmnd->result = DID_ERROR << 16;
			evt->done = ibmvfc_scsi_eh_done;
		} else
			evt->xfer_iu->mad_common.status = IBMVFC_MAD_CRQ_ERROR;

		evt->done(evt);
	} else
		ibmvfc_trc_start(evt);

	return 0;
}

/**
 * ibmvfc_log_error - Log an error for the failed command if appropriate
 * @evt:	ibmvfc event to log
 *
 **/
static void ibmvfc_log_error(struct ibmvfc_event *evt)
{
	struct ibmvfc_cmd *vfc_cmd = &evt->xfer_iu->cmd;
	struct ibmvfc_host *vhost = evt->vhost;
	struct ibmvfc_fcp_rsp *rsp = &vfc_cmd->rsp;
	struct scsi_cmnd *cmnd = evt->cmnd;
	const char *err = unknown_error;
	int index = ibmvfc_get_err_index(vfc_cmd->status, vfc_cmd->error);
	int logerr = 0;
	int rsp_code = 0;

	if (index >= 0) {
		logerr = cmd_status[index].log;
		err = cmd_status[index].name;
	}

	if (!logerr && (vhost->log_level <= (IBMVFC_DEFAULT_LOG_LEVEL + 1)))
		return;

	if (rsp->flags & FCP_RSP_LEN_VALID)
		rsp_code = rsp->data.info.rsp_code;

	scmd_printk(KERN_ERR, cmnd, "Command (%02X) failed: %s (%x:%x) "
		    "flags: %x fcp_rsp: %x, resid=%d, scsi_status: %x\n",
		    cmnd->cmnd[0], err, vfc_cmd->status, vfc_cmd->error,
		    rsp->flags, rsp_code, scsi_get_resid(cmnd), rsp->scsi_status);
}

/**
 * ibmvfc_scsi_done - Handle responses from commands
 * @evt:	ibmvfc event to be handled
 *
 * Used as a callback when sending scsi cmds.
 **/
static void ibmvfc_scsi_done(struct ibmvfc_event *evt)
{
	struct ibmvfc_cmd *vfc_cmd = &evt->xfer_iu->cmd;
	struct ibmvfc_fcp_rsp *rsp = &vfc_cmd->rsp;
	struct scsi_cmnd *cmnd = evt->cmnd;
	u32 rsp_len = 0;
	u32 sense_len = rsp->fcp_sense_len;

	if (cmnd) {
		if (vfc_cmd->response_flags & IBMVFC_ADAPTER_RESID_VALID)
			scsi_set_resid(cmnd, vfc_cmd->adapter_resid);
		else if (rsp->flags & FCP_RESID_UNDER)
			scsi_set_resid(cmnd, rsp->fcp_resid);
		else
			scsi_set_resid(cmnd, 0);

		if (vfc_cmd->status) {
			cmnd->result = ibmvfc_get_err_result(vfc_cmd);

			if (rsp->flags & FCP_RSP_LEN_VALID)
				rsp_len = rsp->fcp_rsp_len;
			if ((sense_len + rsp_len) > SCSI_SENSE_BUFFERSIZE)
				sense_len = SCSI_SENSE_BUFFERSIZE - rsp_len;
			if ((rsp->flags & FCP_SNS_LEN_VALID) && rsp->fcp_sense_len && rsp_len <= 8)
				memcpy(cmnd->sense_buffer, rsp->data.sense + rsp_len, sense_len);
			if ((vfc_cmd->status & IBMVFC_VIOS_FAILURE) && (vfc_cmd->error == IBMVFC_PLOGI_REQUIRED))
				ibmvfc_reinit_host(evt->vhost);

			if (!cmnd->result && (!scsi_get_resid(cmnd) || (rsp->flags & FCP_RESID_OVER)))
				cmnd->result = (DID_ERROR << 16);

			ibmvfc_log_error(evt);
		}

		if (!cmnd->result &&
		    (scsi_bufflen(cmnd) - scsi_get_resid(cmnd) < cmnd->underflow))
			cmnd->result = (DID_ERROR << 16);

		scsi_dma_unmap(cmnd);
		cmnd->scsi_done(cmnd);
	}

	if (evt->eh_comp)
		complete(evt->eh_comp);

	ibmvfc_free_event(evt);
}

/**
 * ibmvfc_host_chkready - Check if the host can accept commands
 * @vhost:	 struct ibmvfc host
 *
 * Returns:
 *	1 if host can accept command / 0 if not
 **/
static inline int ibmvfc_host_chkready(struct ibmvfc_host *vhost)
{
	int result = 0;

	switch (vhost->state) {
	case IBMVFC_LINK_DEAD:
	case IBMVFC_HOST_OFFLINE:
		result = DID_NO_CONNECT << 16;
		break;
	case IBMVFC_NO_CRQ:
	case IBMVFC_INITIALIZING:
	case IBMVFC_HALTED:
	case IBMVFC_LINK_DOWN:
		result = DID_REQUEUE << 16;
		break;
	case IBMVFC_ACTIVE:
		result = 0;
		break;
	};

	return result;
}

/**
 * ibmvfc_queuecommand - The queuecommand function of the scsi template
 * @cmnd:	struct scsi_cmnd to be executed
 * @done:	Callback function to be called when cmnd is completed
 *
 * Returns:
 *	0 on success / other on failure
 **/
static int ibmvfc_queuecommand(struct scsi_cmnd *cmnd,
			       void (*done) (struct scsi_cmnd *))
{
	struct ibmvfc_host *vhost = shost_priv(cmnd->device->host);
	struct fc_rport *rport = starget_to_rport(scsi_target(cmnd->device));
	struct ibmvfc_cmd *vfc_cmd;
	struct ibmvfc_event *evt;
	u8 tag[2];
	int rc;

	if (unlikely((rc = fc_remote_port_chkready(rport))) ||
	    unlikely((rc = ibmvfc_host_chkready(vhost)))) {
		cmnd->result = rc;
		done(cmnd);
		return 0;
	}

	cmnd->result = (DID_OK << 16);
	evt = ibmvfc_get_event(vhost);
	ibmvfc_init_event(evt, ibmvfc_scsi_done, IBMVFC_CMD_FORMAT);
	evt->cmnd = cmnd;
	cmnd->scsi_done = done;
	vfc_cmd = &evt->iu.cmd;
	memset(vfc_cmd, 0, sizeof(*vfc_cmd));
	vfc_cmd->resp.va = (u64)evt->crq.ioba + offsetof(struct ibmvfc_cmd, rsp);
	vfc_cmd->resp.len = sizeof(vfc_cmd->rsp);
	vfc_cmd->frame_type = IBMVFC_SCSI_FCP_TYPE;
	vfc_cmd->payload_len = sizeof(vfc_cmd->iu);
	vfc_cmd->resp_len = sizeof(vfc_cmd->rsp);
	vfc_cmd->cancel_key = (unsigned long)cmnd->device->hostdata;
	vfc_cmd->tgt_scsi_id = rport->port_id;
	vfc_cmd->iu.xfer_len = scsi_bufflen(cmnd);
	int_to_scsilun(cmnd->device->lun, &vfc_cmd->iu.lun);
	memcpy(vfc_cmd->iu.cdb, cmnd->cmnd, cmnd->cmd_len);

	if (scsi_populate_tag_msg(cmnd, tag)) {
		vfc_cmd->task_tag = tag[1];
		switch (tag[0]) {
		case MSG_SIMPLE_TAG:
			vfc_cmd->iu.pri_task_attr = IBMVFC_SIMPLE_TASK;
			break;
		case MSG_HEAD_TAG:
			vfc_cmd->iu.pri_task_attr = IBMVFC_HEAD_OF_QUEUE;
			break;
		case MSG_ORDERED_TAG:
			vfc_cmd->iu.pri_task_attr = IBMVFC_ORDERED_TASK;
			break;
		};
	}

	if (likely(!(rc = ibmvfc_map_sg_data(cmnd, evt, vfc_cmd, vhost->dev))))
		return ibmvfc_send_event(evt, vhost, 0);

	ibmvfc_free_event(evt);
	if (rc == -ENOMEM)
		return SCSI_MLQUEUE_HOST_BUSY;

	if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
		scmd_printk(KERN_ERR, cmnd,
			    "Failed to map DMA buffer for command. rc=%d\n", rc);

	cmnd->result = DID_ERROR << 16;
	done(cmnd);
	return 0;
}

/**
 * ibmvfc_sync_completion - Signal that a synchronous command has completed
 * @evt:	ibmvfc event struct
 *
 **/
static void ibmvfc_sync_completion(struct ibmvfc_event *evt)
{
	/* copy the response back */
	if (evt->sync_iu)
		*evt->sync_iu = *evt->xfer_iu;

	complete(&evt->comp);
}

/**
 * ibmvfc_reset_device - Reset the device with the specified reset type
 * @sdev:	scsi device to reset
 * @type:	reset type
 * @desc:	reset type description for log messages
 *
 * Returns:
 *	0 on success / other on failure
 **/
static int ibmvfc_reset_device(struct scsi_device *sdev, int type, char *desc)
{
	struct ibmvfc_host *vhost = shost_priv(sdev->host);
	struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
	struct ibmvfc_cmd *tmf;
	struct ibmvfc_event *evt = NULL;
	union ibmvfc_iu rsp_iu;
	struct ibmvfc_fcp_rsp *fc_rsp = &rsp_iu.cmd.rsp;
	int rsp_rc = -EBUSY;
	unsigned long flags;
	int rsp_code = 0;

	spin_lock_irqsave(vhost->host->host_lock, flags);
	if (vhost->state == IBMVFC_ACTIVE) {
		evt = ibmvfc_get_event(vhost);
		ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_CMD_FORMAT);

		tmf = &evt->iu.cmd;
		memset(tmf, 0, sizeof(*tmf));
		tmf->resp.va = (u64)evt->crq.ioba + offsetof(struct ibmvfc_cmd, rsp);
		tmf->resp.len = sizeof(tmf->rsp);
		tmf->frame_type = IBMVFC_SCSI_FCP_TYPE;
		tmf->payload_len = sizeof(tmf->iu);
		tmf->resp_len = sizeof(tmf->rsp);
		tmf->cancel_key = (unsigned long)sdev->hostdata;
		tmf->tgt_scsi_id = rport->port_id;
		int_to_scsilun(sdev->lun, &tmf->iu.lun);
		tmf->flags = (IBMVFC_NO_MEM_DESC | IBMVFC_TMF);
		tmf->iu.tmf_flags = type;
		evt->sync_iu = &rsp_iu;

		init_completion(&evt->comp);
		rsp_rc = ibmvfc_send_event(evt, vhost, default_timeout);
	}
	spin_unlock_irqrestore(vhost->host->host_lock, flags);

	if (rsp_rc != 0) {
		sdev_printk(KERN_ERR, sdev, "Failed to send %s reset event. rc=%d\n",
			    desc, rsp_rc);
		return -EIO;
	}

	sdev_printk(KERN_INFO, sdev, "Resetting %s\n", desc);
	wait_for_completion(&evt->comp);

	if (rsp_iu.cmd.status) {
		if (fc_rsp->flags & FCP_RSP_LEN_VALID)
			rsp_code = fc_rsp->data.info.rsp_code;

		sdev_printk(KERN_ERR, sdev, "%s reset failed: %s (%x:%x) "
			    "flags: %x fcp_rsp: %x, scsi_status: %x\n",
			    desc, ibmvfc_get_cmd_error(rsp_iu.cmd.status, rsp_iu.cmd.error),
			    rsp_iu.cmd.status, rsp_iu.cmd.error, fc_rsp->flags, rsp_code,
			    fc_rsp->scsi_status);
		rsp_rc = -EIO;
	} else
		sdev_printk(KERN_INFO, sdev, "%s reset successful\n", desc);

	spin_lock_irqsave(vhost->host->host_lock, flags);
	ibmvfc_free_event(evt);
	spin_unlock_irqrestore(vhost->host->host_lock, flags);
	return rsp_rc;
}

/**
 * ibmvfc_abort_task_set - Abort outstanding commands to the device
 * @sdev:	scsi device to abort commands
 *
 * This sends an Abort Task Set to the VIOS for the specified device. This does
 * NOT send any cancel to the VIOS. That must be done separately.
 *
 * Returns:
 *	0 on success / other on failure
 **/
static int ibmvfc_abort_task_set(struct scsi_device *sdev)
{
	struct ibmvfc_host *vhost = shost_priv(sdev->host);
	struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
	struct ibmvfc_cmd *tmf;
	struct ibmvfc_event *evt, *found_evt;
	union ibmvfc_iu rsp_iu;
	struct ibmvfc_fcp_rsp *fc_rsp = &rsp_iu.cmd.rsp;
	int rsp_rc = -EBUSY;
	unsigned long flags;
	int rsp_code = 0;

	spin_lock_irqsave(vhost->host->host_lock, flags);
	found_evt = NULL;
	list_for_each_entry(evt, &vhost->sent, queue) {
		if (evt->cmnd && evt->cmnd->device == sdev) {
			found_evt = evt;
			break;
		}
	}

	if (!found_evt) {
		if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
			sdev_printk(KERN_INFO, sdev, "No events found to abort\n");
		spin_unlock_irqrestore(vhost->host->host_lock, flags);
		return 0;
	}

	if (vhost->state == IBMVFC_ACTIVE) {
		evt = ibmvfc_get_event(vhost);
		ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_CMD_FORMAT);

		tmf = &evt->iu.cmd;
		memset(tmf, 0, sizeof(*tmf));
		tmf->resp.va = (u64)evt->crq.ioba + offsetof(struct ibmvfc_cmd, rsp);
		tmf->resp.len = sizeof(tmf->rsp);
		tmf->frame_type = IBMVFC_SCSI_FCP_TYPE;
		tmf->payload_len = sizeof(tmf->iu);
		tmf->resp_len = sizeof(tmf->rsp);
		tmf->cancel_key = (unsigned long)sdev->hostdata;
		tmf->tgt_scsi_id = rport->port_id;
		int_to_scsilun(sdev->lun, &tmf->iu.lun);
		tmf->flags = (IBMVFC_NO_MEM_DESC…