xref: /illumos-gate/usr/src/uts/common/io/comstar/port/iscsit/iscsit.c (revision 61dfa509)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright 2017 Nexenta Systems, Inc.
 * Copyright (c) 2017, Joyent, Inc.  All rights reserved.
 */

#include <sys/cpuvar.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/modctl.h>
#include <sys/sysmacros.h>
#include <sys/socket.h>
#include <sys/strsubr.h>
#include <sys/nvpair.h>

#include <sys/stmf.h>
#include <sys/stmf_ioctl.h>
#include <sys/portif.h>
#include <sys/idm/idm.h>
#include <sys/idm/idm_conn_sm.h>

#include "iscsit_isns.h"
#include "iscsit.h"

#define	ISCSIT_VERSION		BUILD_DATE "-1.18dev"
#define	ISCSIT_NAME_VERSION	"COMSTAR ISCSIT v" ISCSIT_VERSION

/*
 * DDI entry points.
 */
static int iscsit_drv_attach(dev_info_t *, ddi_attach_cmd_t);
static int iscsit_drv_detach(dev_info_t *, ddi_detach_cmd_t);
static int iscsit_drv_getinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
static int iscsit_drv_open(dev_t *, int, int, cred_t *);
static int iscsit_drv_close(dev_t, int, int, cred_t *);
static boolean_t iscsit_drv_busy(void);
static int iscsit_drv_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);

extern struct mod_ops mod_miscops;


static struct cb_ops iscsit_cb_ops = {
	iscsit_drv_open,	/* cb_open */
	iscsit_drv_close,	/* cb_close */
	nodev,			/* cb_strategy */
	nodev,			/* cb_print */
	nodev,			/* cb_dump */
	nodev,			/* cb_read */
	nodev,			/* cb_write */
	iscsit_drv_ioctl,	/* cb_ioctl */
	nodev,			/* cb_devmap */
	nodev,			/* cb_mmap */
	nodev,			/* cb_segmap */
	nochpoll,		/* cb_chpoll */
	ddi_prop_op,		/* cb_prop_op */
	NULL,			/* cb_streamtab */
	D_MP,			/* cb_flag */
	CB_REV,			/* cb_rev */
	nodev,			/* cb_aread */
	nodev,			/* cb_awrite */
};

static struct dev_ops iscsit_dev_ops = {
	DEVO_REV,		/* devo_rev */
	0,			/* devo_refcnt */
	iscsit_drv_getinfo,	/* devo_getinfo */
	nulldev,		/* devo_identify */
	nulldev,		/* devo_probe */
	iscsit_drv_attach,	/* devo_attach */
	iscsit_drv_detach,	/* devo_detach */
	nodev,			/* devo_reset */
	&iscsit_cb_ops,		/* devo_cb_ops */
	NULL,			/* devo_bus_ops */
	NULL,			/* devo_power */
	ddi_quiesce_not_needed,	/* quiesce */
};

static struct modldrv modldrv = {
	&mod_driverops,
	"iSCSI Target",
	&iscsit_dev_ops,
};

static struct modlinkage modlinkage = {
	MODREV_1,
	&modldrv,
	NULL,
};


iscsit_global_t iscsit_global;

kmem_cache_t	*iscsit_status_pdu_cache;

boolean_t	iscsit_sm_logging = B_FALSE;

kmutex_t	login_sm_session_mutex;

static idm_status_t iscsit_init(dev_info_t *dip);
static idm_status_t iscsit_enable_svc(iscsit_hostinfo_t *hostinfo);
static void iscsit_disable_svc(void);

static boolean_t
iscsit_check_cmdsn_and_queue(idm_pdu_t *rx_pdu);

static void
iscsit_add_pdu_to_queue(iscsit_sess_t *ist, idm_pdu_t *rx_pdu);

static idm_pdu_t *
iscsit_remove_pdu_from_queue(iscsit_sess_t *ist, uint32_t cmdsn);

static void
iscsit_process_pdu_in_queue(iscsit_sess_t *ist);

static void
iscsit_rxpdu_queue_monitor_session(iscsit_sess_t *ist);

static void
iscsit_rxpdu_queue_monitor(void *arg);

static void
iscsit_post_staged_pdu(idm_pdu_t *rx_pdu);

static void
iscsit_post_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu);

static void
iscsit_op_scsi_task_mgmt(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

static void
iscsit_pdu_op_noop(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

static void
iscsit_pdu_op_login_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

void
iscsit_pdu_op_text_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

static void
iscsit_pdu_op_logout_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

int iscsit_cmd_window();

static  int
iscsit_sna_lt(uint32_t sn1, uint32_t sn2);

void
iscsit_set_cmdsn(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);

static void
iscsit_deferred_dispatch(idm_pdu_t *rx_pdu);

static void
iscsit_deferred(void *rx_pdu_void);

static idm_status_t
iscsit_conn_accept(idm_conn_t *ic);

static idm_status_t
iscsit_ffp_enabled(idm_conn_t *ic);

static idm_status_t
iscsit_ffp_disabled(idm_conn_t *ic, idm_ffp_disable_t disable_class);

static idm_status_t
iscsit_conn_lost(idm_conn_t *ic);

static idm_status_t
iscsit_conn_destroy(idm_conn_t *ic);

static stmf_data_buf_t *
iscsit_dbuf_alloc(scsi_task_t *task, uint32_t size, uint32_t *pminsize,
    uint32_t flags);

static void
iscsit_dbuf_free(stmf_dbuf_store_t *ds, stmf_data_buf_t *dbuf);

static void
iscsit_buf_xfer_cb(idm_buf_t *idb, idm_status_t status);

static void
iscsit_send_good_status_done(idm_pdu_t *pdu, idm_status_t status);

static void
iscsit_send_status_done(idm_pdu_t *pdu, idm_status_t status);

static stmf_status_t
iscsit_idm_to_stmf(idm_status_t idmrc);

static iscsit_task_t *
iscsit_task_alloc(iscsit_conn_t *ict);

static void
iscsit_task_free(iscsit_task_t *itask);

static iscsit_task_t *
iscsit_tm_task_alloc(iscsit_conn_t *ict);

static void
iscsit_tm_task_free(iscsit_task_t *itask);

static idm_status_t
iscsit_task_start(iscsit_task_t *itask);

static void
iscsit_task_done(iscsit_task_t *itask);

static int
iscsit_status_pdu_constructor(void *pdu_void, void *arg, int flags);

static void
iscsit_pp_cb(struct stmf_port_provider *pp, int cmd, void *arg, uint32_t flags);

static it_cfg_status_t
iscsit_config_merge(it_config_t *cfg);

static idm_status_t
iscsit_login_fail(idm_conn_t *ic);

static boolean_t iscsit_cmdsn_in_window(iscsit_conn_t *ict, uint32_t cmdsn);
static void iscsit_send_direct_scsi_resp(iscsit_conn_t *ict, idm_pdu_t *rx_pdu,
    uint8_t response, uint8_t cmd_status);
static void iscsit_send_task_mgmt_resp(idm_pdu_t *tm_resp_pdu,
    uint8_t tm_status);

/*
 * MC/S: Out-of-order commands are staged on a session-wide wait
 * queue until a system-tunable threshold is reached. A separate
 * thread is used to scan the staging queue on all the session,
 * If a delayed PDU does not arrive within a timeout, the target
 * will advance to the staged PDU that is next in sequence, skipping
 * over the missing PDU(s) to go past a hole in the sequence.
 */
volatile int rxpdu_queue_threshold = ISCSIT_RXPDU_QUEUE_THRESHOLD;

static kmutex_t		iscsit_rxpdu_queue_monitor_mutex;
kthread_t		*iscsit_rxpdu_queue_monitor_thr_id;
static kt_did_t		iscsit_rxpdu_queue_monitor_thr_did;
static boolean_t	iscsit_rxpdu_queue_monitor_thr_running;
static kcondvar_t	iscsit_rxpdu_queue_monitor_cv;

int
_init(void)
{
	int rc;

	rw_init(&iscsit_global.global_rwlock, NULL, RW_DRIVER, NULL);
	mutex_init(&iscsit_global.global_state_mutex, NULL,
	    MUTEX_DRIVER, NULL);
	iscsit_global.global_svc_state = ISE_DETACHED;

	mutex_init(&iscsit_rxpdu_queue_monitor_mutex, NULL,
	    MUTEX_DRIVER, NULL);
	mutex_init(&login_sm_session_mutex, NULL, MUTEX_DRIVER, NULL);
	iscsit_rxpdu_queue_monitor_thr_id = NULL;
	iscsit_rxpdu_queue_monitor_thr_running = B_FALSE;
	cv_init(&iscsit_rxpdu_queue_monitor_cv, NULL, CV_DEFAULT, NULL);

	if ((rc = mod_install(&modlinkage)) != 0) {
		mutex_destroy(&iscsit_global.global_state_mutex);
		rw_destroy(&iscsit_global.global_rwlock);
		return (rc);
	}

	return (rc);
}

int
_info(struct modinfo *modinfop)
{
	return (mod_info(&modlinkage, modinfop));
}

int
_fini(void)
{
	int rc;

	rc = mod_remove(&modlinkage);

	if (rc == 0) {
		mutex_destroy(&iscsit_rxpdu_queue_monitor_mutex);
		mutex_destroy(&login_sm_session_mutex);
		cv_destroy(&iscsit_rxpdu_queue_monitor_cv);
		mutex_destroy(&iscsit_global.global_state_mutex);
		rw_destroy(&iscsit_global.global_rwlock);
	}

	return (rc);
}

/*
 * DDI entry points.
 */

/* ARGSUSED */
static int
iscsit_drv_getinfo(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg,
    void **result)
{
	ulong_t instance = getminor((dev_t)arg);

	switch (cmd) {
	case DDI_INFO_DEVT2DEVINFO:
		*result = iscsit_global.global_dip;
		return (DDI_SUCCESS);

	case DDI_INFO_DEVT2INSTANCE:
		*result = (void *)instance;
		return (DDI_SUCCESS);

	default:
		break;
	}

	return (DDI_FAILURE);
}

static int
iscsit_drv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
	if (cmd != DDI_ATTACH) {
		return (DDI_FAILURE);
	}

	if (ddi_get_instance(dip) != 0) {
		/* we only allow instance 0 to attach */
		return (DDI_FAILURE);
	}

	/* create the minor node */
	if (ddi_create_minor_node(dip, ISCSIT_MODNAME, S_IFCHR, 0,
	    DDI_PSEUDO, 0) != DDI_SUCCESS) {
		cmn_err(CE_WARN, "iscsit_drv_attach: "
		    "failed creating minor node");
		return (DDI_FAILURE);
	}

	if (iscsit_init(dip) != IDM_STATUS_SUCCESS) {
		cmn_err(CE_WARN, "iscsit_drv_attach: "
		    "failed to initialize");
		ddi_remove_minor_node(dip, NULL);
		return (DDI_FAILURE);
	}

	iscsit_global.global_svc_state = ISE_DISABLED;
	iscsit_global.global_dip = dip;

	return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
iscsit_drv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
	if (cmd != DDI_DETACH)
		return (DDI_FAILURE);

	/*
	 * drv_detach is called in a context that owns the
	 * device node for the /dev/pseudo device.  If this thread blocks
	 * for any resource, other threads that need the /dev/pseudo device
	 * may end up in a deadlock with this thread.Hence, we use a
	 * separate lock just for the structures that drv_detach needs
	 * to access.
	 */
	mutex_enter(&iscsit_global.global_state_mutex);
	if (iscsit_drv_busy()) {
		mutex_exit(&iscsit_global.global_state_mutex);
		return (EBUSY);
	}

	iscsit_global.global_dip = NULL;
	ddi_remove_minor_node(dip, NULL);

	ldi_ident_release(iscsit_global.global_li);
	iscsit_global.global_svc_state = ISE_DETACHED;

	mutex_exit(&iscsit_global.global_state_mutex);

	return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
iscsit_drv_open(dev_t *devp, int flag, int otyp, cred_t *credp)
{
	return (0);
}

/* ARGSUSED */
static int
iscsit_drv_close(dev_t dev, int flag, int otyp, cred_t *credp)
{
	return (0);
}

static boolean_t
iscsit_drv_busy(void)
{
	ASSERT(MUTEX_HELD(&iscsit_global.global_state_mutex));

	switch (iscsit_global.global_svc_state) {
	case ISE_DISABLED:
	case ISE_DETACHED:
		return (B_FALSE);
	default:
		return (B_TRUE);
	}
	/* NOTREACHED */
}

/* ARGSUSED */
static int
iscsit_drv_ioctl(dev_t drv, int cmd, intptr_t argp, int flag, cred_t *cred,
    int *retval)
{
	iscsit_ioc_set_config_t		setcfg;
	iscsit_ioc_set_config32_t	setcfg32;
	char				*cfg_pnvlist = NULL;
	nvlist_t			*cfg_nvlist = NULL;
	it_config_t			*cfg = NULL;
	idm_status_t			idmrc;
	int				rc = 0;

	if (drv_priv(cred) != 0) {
		return (EPERM);
	}

	mutex_enter(&iscsit_global.global_state_mutex);

	/*
	 * Validate ioctl requests against global service state
	 */
	switch (iscsit_global.global_svc_state) {
	case ISE_ENABLED:
		if (cmd == ISCSIT_IOC_DISABLE_SVC) {
			iscsit_global.global_svc_state = ISE_DISABLING;
		} else if (cmd == ISCSIT_IOC_ENABLE_SVC) {
			/* Already enabled */
			mutex_exit(&iscsit_global.global_state_mutex);
			return (0);
		} else {
			iscsit_global.global_svc_state = ISE_BUSY;
		}
		break;
	case ISE_DISABLED:
		if (cmd == ISCSIT_IOC_ENABLE_SVC) {
			iscsit_global.global_svc_state = ISE_ENABLING;
		} else if (cmd == ISCSIT_IOC_DISABLE_SVC) {
			/* Already disabled */
			mutex_exit(&iscsit_global.global_state_mutex);
			return (0);
		} else {
			rc = EFAULT;
		}
		break;
	case ISE_BUSY:
	case ISE_ENABLING:
	case ISE_DISABLING:
		rc = EAGAIN;
		break;
	case ISE_DETACHED:
	default:
		rc = EFAULT;
		break;
	}

	mutex_exit(&iscsit_global.global_state_mutex);
	if (rc != 0)
		return (rc);

	/* Handle ioctl request (enable/disable have already been handled) */
	switch (cmd) {
	case ISCSIT_IOC_SET_CONFIG:
		/* Any errors must set state back to ISE_ENABLED */
		switch (ddi_model_convert_from(flag & FMODELS)) {
		case DDI_MODEL_ILP32:
			if (ddi_copyin((void *)argp, &setcfg32,
			    sizeof (iscsit_ioc_set_config32_t), flag) != 0) {
				rc = EFAULT;
				goto cleanup;
			}

			setcfg.set_cfg_pnvlist =
			    (char *)((uintptr_t)setcfg32.set_cfg_pnvlist);
			setcfg.set_cfg_vers = setcfg32.set_cfg_vers;
			setcfg.set_cfg_pnvlist_len =
			    setcfg32.set_cfg_pnvlist_len;
			break;
		case DDI_MODEL_NONE:
			if (ddi_copyin((void *)argp, &setcfg,
			    sizeof (iscsit_ioc_set_config_t), flag) != 0) {
				rc = EFAULT;
				goto cleanup;
			}
			break;
		default:
			rc = EFAULT;
			goto cleanup;
		}

		/* Check API version */
		if (setcfg.set_cfg_vers != ISCSIT_API_VERS0) {
			rc = EINVAL;
			goto cleanup;
		}

		/* Config is in packed nvlist format so unpack it */
		cfg_pnvlist = kmem_alloc(setcfg.set_cfg_pnvlist_len,
		    KM_SLEEP);
		ASSERT(cfg_pnvlist != NULL);

		if (ddi_copyin(setcfg.set_cfg_pnvlist, cfg_pnvlist,
		    setcfg.set_cfg_pnvlist_len, flag) != 0) {
			rc = EFAULT;
			goto cleanup;
		}

		rc = nvlist_unpack(cfg_pnvlist, setcfg.set_cfg_pnvlist_len,
		    &cfg_nvlist, KM_SLEEP);
		if (rc != 0) {
			goto cleanup;
		}

		/* Translate nvlist */
		rc = it_nv_to_config(cfg_nvlist, &cfg);
		if (rc != 0) {
			cmn_err(CE_WARN, "Configuration is invalid");
			goto cleanup;
		}

		/* Update config */
		rc = iscsit_config_merge(cfg);
		/* FALLTHROUGH */

cleanup:
		if (cfg)
			it_config_free_cmn(cfg);
		if (cfg_pnvlist)
			kmem_free(cfg_pnvlist, setcfg.set_cfg_pnvlist_len);
		if (cfg_nvlist)
			nvlist_free(cfg_nvlist);

		/*
		 * Now that the reconfig is complete set our state back to
		 * enabled.
		 */
		mutex_enter(&iscsit_global.global_state_mutex);
		iscsit_global.global_svc_state = ISE_ENABLED;
		mutex_exit(&iscsit_global.global_state_mutex);
		break;
	case ISCSIT_IOC_ENABLE_SVC: {
		iscsit_hostinfo_t hostinfo;

		if (ddi_copyin((void *)argp, &hostinfo.length,
		    sizeof (hostinfo.length), flag) != 0) {
			mutex_enter(&iscsit_global.global_state_mutex);
			iscsit_global.global_svc_state = ISE_DISABLED;
			mutex_exit(&iscsit_global.global_state_mutex);
			return (EFAULT);
		}

		if (hostinfo.length > sizeof (hostinfo.fqhn))
			hostinfo.length = sizeof (hostinfo.fqhn);

		if (ddi_copyin((void *)((caddr_t)argp +
		    sizeof (hostinfo.length)), &hostinfo.fqhn,
		    hostinfo.length, flag) != 0) {
			mutex_enter(&iscsit_global.global_state_mutex);
			iscsit_global.global_svc_state = ISE_DISABLED;
			mutex_exit(&iscsit_global.global_state_mutex);
			return (EFAULT);
		}

		idmrc = iscsit_enable_svc(&hostinfo);
		mutex_enter(&iscsit_global.global_state_mutex);
		if (idmrc == IDM_STATUS_SUCCESS) {
			iscsit_global.global_svc_state = ISE_ENABLED;
		} else {
			rc = EIO;
			iscsit_global.global_svc_state = ISE_DISABLED;
		}
		mutex_exit(&iscsit_global.global_state_mutex);
		break;
	}
	case ISCSIT_IOC_DISABLE_SVC:
		iscsit_disable_svc();
		mutex_enter(&iscsit_global.global_state_mutex);
		iscsit_global.global_svc_state = ISE_DISABLED;
		mutex_exit(&iscsit_global.global_state_mutex);
		break;

	default:
		rc = EINVAL;
		mutex_enter(&iscsit_global.global_state_mutex);
		iscsit_global.global_svc_state = ISE_ENABLED;
		mutex_exit(&iscsit_global.global_state_mutex);
	}

	return (rc);
}

static idm_status_t
iscsit_init(dev_info_t *dip)
{
	int			rc;

	rc = ldi_ident_from_dip(dip, &iscsit_global.global_li);
	ASSERT(rc == 0);  /* Failure indicates invalid argument */

	iscsit_global.global_svc_state = ISE_DISABLED;

	return (IDM_STATUS_SUCCESS);
}

/*
 * iscsit_enable_svc
 *
 * registers all the configured targets and target portals with STMF
 */
static idm_status_t
iscsit_enable_svc(iscsit_hostinfo_t *hostinfo)
{
	stmf_port_provider_t	*pp;
	stmf_dbuf_store_t	*dbuf_store;
	boolean_t		did_iscsit_isns_init;
	idm_status_t		retval = IDM_STATUS_SUCCESS;

	ASSERT(iscsit_global.global_svc_state == ISE_ENABLING);

	/*
	 * Make sure that can tell if we have partially allocated
	 * in case we need to exit and tear down anything allocated.
	 */
	iscsit_global.global_tsih_pool = NULL;
	iscsit_global.global_dbuf_store = NULL;
	iscsit_status_pdu_cache = NULL;
	pp = NULL;
	iscsit_global.global_pp = NULL;
	iscsit_global.global_default_tpg = NULL;
	did_iscsit_isns_init = B_FALSE;
	iscsit_global.global_dispatch_taskq = NULL;

	/* Setup remaining fields in iscsit_global_t */
	idm_refcnt_init(&iscsit_global.global_refcnt,
	    &iscsit_global);

	avl_create(&iscsit_global.global_discovery_sessions,
	    iscsit_sess_avl_compare, sizeof (iscsit_sess_t),
	    offsetof(iscsit_sess_t, ist_tgt_ln));

	avl_create(&iscsit_global.global_target_list,
	    iscsit_tgt_avl_compare, sizeof (iscsit_tgt_t),
	    offsetof(iscsit_tgt_t, target_global_ln));

	list_create(&iscsit_global.global_deleted_target_list,
	    sizeof (iscsit_tgt_t),
	    offsetof(iscsit_tgt_t, target_global_deleted_ln));

	avl_create(&iscsit_global.global_tpg_list,
	    iscsit_tpg_avl_compare, sizeof (iscsit_tpg_t),
	    offsetof(iscsit_tpg_t, tpg_global_ln));

	avl_create(&iscsit_global.global_ini_list,
	    iscsit_ini_avl_compare, sizeof (iscsit_ini_t),
	    offsetof(iscsit_ini_t, ini_global_ln));

	iscsit_global.global_tsih_pool = vmem_create("iscsit_tsih_pool",
	    (void *)1, ISCSI_MAX_TSIH, 1, NULL, NULL, NULL, 0,
	    VM_SLEEP | VMC_IDENTIFIER);

	/*
	 * Setup STMF dbuf store.  Our buffers are bound to a specific
	 * connection so we really can't let STMF cache buffers for us.
	 * Consequently we'll just allocate one global buffer store.
	 */
	dbuf_store = stmf_alloc(STMF_STRUCT_DBUF_STORE, 0, 0);
	if (dbuf_store == NULL) {
		retval = IDM_STATUS_FAIL;
		goto tear_down_and_return;
	}
	dbuf_store->ds_alloc_data_buf = iscsit_dbuf_alloc;
	dbuf_store->ds_free_data_buf = iscsit_dbuf_free;
	dbuf_store->ds_port_private = NULL;
	iscsit_global.global_dbuf_store = dbuf_store;

	/* Status PDU cache */
	iscsit_status_pdu_cache = kmem_cache_create("iscsit_status_pdu_cache",
	    sizeof (idm_pdu_t) + sizeof (iscsi_scsi_rsp_hdr_t), 8,
	    &iscsit_status_pdu_constructor,
	    NULL, NULL, NULL, NULL, KM_SLEEP);

	/* Default TPG and portal */
	iscsit_global.global_default_tpg = iscsit_tpg_createdefault();
	if (iscsit_global.global_default_tpg == NULL) {
		retval = IDM_STATUS_FAIL;
		goto tear_down_and_return;
	}

	/* initialize isns client */
	(void) iscsit_isns_init(hostinfo);
	did_iscsit_isns_init = B_TRUE;

	/* Register port provider */
	pp = stmf_alloc(STMF_STRUCT_PORT_PROVIDER, 0, 0);
	if (pp == NULL) {
		retval = IDM_STATUS_FAIL;
		goto tear_down_and_return;
	}

	pp->pp_portif_rev = PORTIF_REV_1;
	pp->pp_instance = 0;
	pp->pp_name = ISCSIT_MODNAME;
	pp->pp_cb = iscsit_pp_cb;

	iscsit_global.global_pp = pp;


	if (stmf_register_port_provider(pp) != STMF_SUCCESS) {
		retval = IDM_STATUS_FAIL;
		goto tear_down_and_return;
	}

	iscsit_global.global_dispatch_taskq = taskq_create("iscsit_dispatch",
	    1, minclsyspri, 16, 16, TASKQ_PREPOPULATE);

	/* Scan staged PDUs, meaningful in MC/S situations */
	iscsit_rxpdu_queue_monitor_start();

	return (IDM_STATUS_SUCCESS);

tear_down_and_return:

	if (iscsit_global.global_dispatch_taskq) {
		taskq_destroy(iscsit_global.global_dispatch_taskq);
		iscsit_global.global_dispatch_taskq = NULL;
	}

	if (did_iscsit_isns_init)
		iscsit_isns_fini();

	if (iscsit_global.global_default_tpg) {
		iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);
		iscsit_global.global_default_tpg = NULL;
	}

	if (iscsit_global.global_pp)
		iscsit_global.global_pp = NULL;

	if (pp)
		stmf_free(pp);

	if (iscsit_status_pdu_cache) {
		kmem_cache_destroy(iscsit_status_pdu_cache);
		iscsit_status_pdu_cache = NULL;
	}

	if (iscsit_global.global_dbuf_store) {
		stmf_free(iscsit_global.global_dbuf_store);
		iscsit_global.global_dbuf_store = NULL;
	}

	if (iscsit_global.global_tsih_pool) {
		vmem_destroy(iscsit_global.global_tsih_pool);
		iscsit_global.global_tsih_pool = NULL;
	}

	avl_destroy(&iscsit_global.global_ini_list);
	avl_destroy(&iscsit_global.global_tpg_list);
	list_destroy(&iscsit_global.global_deleted_target_list);
	avl_destroy(&iscsit_global.global_target_list);
	avl_destroy(&iscsit_global.global_discovery_sessions);

	idm_refcnt_destroy(&iscsit_global.global_refcnt);

	return (retval);
}

/*
 * iscsit_disable_svc
 *
 * clean up all existing connections and deregister targets from STMF
 */
static void
iscsit_disable_svc(void)
{
	iscsit_sess_t	*sess;

	ASSERT(iscsit_global.global_svc_state == ISE_DISABLING);

	iscsit_rxpdu_queue_monitor_stop();

	/* tear down discovery sessions */
	for (sess = avl_first(&iscsit_global.global_discovery_sessions);
	    sess != NULL;
	    sess = AVL_NEXT(&iscsit_global.global_discovery_sessions, sess))
		iscsit_sess_close(sess);

	/*
	 * Passing NULL to iscsit_config_merge tells it to go to an empty
	 * config.
	 */
	(void) iscsit_config_merge(NULL);

	/*
	 * Wait until there are no more global references
	 */
	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
	idm_refcnt_destroy(&iscsit_global.global_refcnt);

	/*
	 * Default TPG must be destroyed after global_refcnt is 0.
	 */
	iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);

	avl_destroy(&iscsit_global.global_discovery_sessions);
	list_destroy(&iscsit_global.global_deleted_target_list);
	avl_destroy(&iscsit_global.global_target_list);
	avl_destroy(&iscsit_global.global_tpg_list);
	avl_destroy(&iscsit_global.global_ini_list);

	taskq_destroy(iscsit_global.global_dispatch_taskq);

	iscsit_isns_fini();

	stmf_free(iscsit_global.global_dbuf_store);
	iscsit_global.global_dbuf_store = NULL;

	(void) stmf_deregister_port_provider(iscsit_global.global_pp);
	stmf_free(iscsit_global.global_pp);
	iscsit_global.global_pp = NULL;

	kmem_cache_destroy(iscsit_status_pdu_cache);
	iscsit_status_pdu_cache = NULL;

	vmem_destroy(iscsit_global.global_tsih_pool);
	iscsit_global.global_tsih_pool = NULL;
}

void
iscsit_global_hold()
{
	/*
	 * To take out a global hold, we must either own the global
	 * state mutex or we must be running inside of an ioctl that
	 * has set the global state to ISE_BUSY, ISE_DISABLING, or
	 * ISE_ENABLING.  We don't track the "owner" for these flags,
	 * so just checking if they are set is enough for now.
	 */
	ASSERT((iscsit_global.global_svc_state == ISE_ENABLING) ||
	    (iscsit_global.global_svc_state == ISE_DISABLING) ||
	    (iscsit_global.global_svc_state == ISE_BUSY) ||
	    MUTEX_HELD(&iscsit_global.global_state_mutex));

	idm_refcnt_hold(&iscsit_global.global_refcnt);
}

void
iscsit_global_rele()
{
	idm_refcnt_rele(&iscsit_global.global_refcnt);
}

void
iscsit_global_wait_ref()
{
	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
}

/*
 * IDM callbacks
 */

/*ARGSUSED*/
void
iscsit_rx_pdu(idm_conn_t *ic, idm_pdu_t *rx_pdu)
{
	iscsit_conn_t *ict = ic->ic_handle;
	switch (IDM_PDU_OPCODE(rx_pdu)) {
	case ISCSI_OP_SCSI_CMD:
		ASSERT(0); /* Shouldn't happen */
		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
		break;
	case ISCSI_OP_SNACK_CMD:
		/*
		 * We'll need to handle this when we support ERL1/2.  For
		 * now we treat it as a protocol error.
		 */
		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
		idm_conn_event(ic, CE_TRANSPORT_FAIL, 0);
		break;
	case ISCSI_OP_SCSI_TASK_MGT_MSG:
		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
			iscsit_set_cmdsn(ict, rx_pdu);
			iscsit_op_scsi_task_mgmt(ict, rx_pdu);
		}
		break;
	case ISCSI_OP_NOOP_OUT:
	case ISCSI_OP_LOGIN_CMD:
	case ISCSI_OP_TEXT_CMD:
	case ISCSI_OP_LOGOUT_CMD:
		/*
		 * If/when we switch to userland processing these PDU's
		 * will be handled by iscsitd.
		 */
		iscsit_deferred_dispatch(rx_pdu);
		break;
	default:
		/* Protocol error */
		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
		idm_conn_event(ic, CE_TRANSPORT_FAIL, 0);
		break;
	}
}

/*ARGSUSED*/
void
iscsit_rx_pdu_error(idm_conn_t *ic, idm_pdu_t *rx_pdu, idm_status_t status)
{
	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
}

/*
 * iscsit_rx_scsi_rsp -- cause the connection to be closed if response rx'd
 *
 * A target sends an SCSI Response PDU, it should never receive one.
 * This has been seen when running the Codemonicon suite of tests which
 * does negative testing of the protocol. If such a condition occurs using
 * a normal initiator it most likely means there's data corruption in the
 * header and that's grounds for dropping the connection as well.
 */
void
iscsit_rx_scsi_rsp(idm_conn_t *ic, idm_pdu_t *rx_pdu)
{
	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
	idm_conn_event(ic, CE_TRANSPORT_FAIL, 0);
}

void
iscsit_task_aborted(idm_task_t *idt, idm_status_t status)
{
	iscsit_task_t *itask = idt->idt_private;

	switch (status) {
	case IDM_STATUS_SUSPENDED:
		break;