xref: /illumos-gate/usr/src/uts/common/io/idm/idm.c (revision a98e9e2e)

/*
 * 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. All rights reserved.
 */

#include <sys/cpuvar.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/modctl.h>

#include <sys/socket.h>
#include <sys/strsubr.h>
#include <sys/sysmacros.h>

#include <sys/socketvar.h>
#include <netinet/in.h>

#include <sys/idm/idm.h>
#include <sys/idm/idm_so.h>

#define	IDM_NAME_VERSION	"iSCSI Data Mover"

extern struct mod_ops mod_miscops;
extern struct mod_ops mod_miscops;

static struct modlmisc modlmisc = {
	&mod_miscops,	/* Type of module */
	IDM_NAME_VERSION
};

static struct modlinkage modlinkage = {
	MODREV_1, (void *)&modlmisc, NULL
};

extern void idm_wd_thread(void *arg);

static int _idm_init(void);
static int _idm_fini(void);
static void idm_buf_bind_in_locked(idm_task_t *idt, idm_buf_t *buf);
static void idm_buf_bind_out_locked(idm_task_t *idt, idm_buf_t *buf);
static void idm_buf_unbind_in_locked(idm_task_t *idt, idm_buf_t *buf);
static void idm_buf_unbind_out_locked(idm_task_t *idt, idm_buf_t *buf);
static stmf_status_t idm_task_abort_one(idm_conn_t *ic, idm_task_t *idt,
    idm_abort_type_t abort_type);
static void idm_task_aborted(idm_task_t *idt, idm_status_t status);
static idm_pdu_t *idm_pdu_alloc_common(uint_t hdrlen, uint_t datalen,
    int sleepflag);

boolean_t idm_conn_logging = 0;
boolean_t idm_svc_logging = 0;
#ifdef DEBUG
boolean_t idm_pattern_checking = 1;
#else
boolean_t idm_pattern_checking = 0;
#endif

/*
 * Potential tuneable for the maximum number of tasks.  Default to
 * IDM_TASKIDS_MAX
 */

uint32_t	idm_max_taskids = IDM_TASKIDS_MAX;

/*
 * Global list of transport handles
 *   These are listed in preferential order, so we can simply take the
 *   first "it_conn_is_capable" hit. Note also that the order maps to
 *   the order of the idm_transport_type_t list.
 */
idm_transport_t idm_transport_list[] = {

	/* iSER on InfiniBand transport handle */
	{IDM_TRANSPORT_TYPE_ISER,	/* type */
	"/devices/ib/iser@0:iser",	/* device path */
	NULL,				/* LDI handle */
	NULL,				/* transport ops */
	NULL},				/* transport caps */

	/* IDM native sockets transport handle */
	{IDM_TRANSPORT_TYPE_SOCKETS,	/* type */
	NULL,				/* device path */
	NULL,				/* LDI handle */
	NULL,				/* transport ops */
	NULL}				/* transport caps */

};

idm_global_t idm;	/* Global state */

int
_init(void)
{
	int rc;

	if ((rc = _idm_init()) != 0) {
		return (rc);
	}

	return (mod_install(&modlinkage));
}

int
_fini(void)
{
	int rc;

	if ((rc = _idm_fini()) != 0) {
		return (rc);
	}

	if ((rc = mod_remove(&modlinkage)) != 0) {
		return (rc);
	}

	return (rc);
}

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

/*
 * idm_transport_register()
 *
 * Provides a mechanism for an IDM transport driver to register its
 * transport ops and caps with the IDM kernel module. Invoked during
 * a transport driver's attach routine.
 */
idm_status_t
idm_transport_register(idm_transport_attr_t *attr)
{
	ASSERT(attr->it_ops != NULL);
	ASSERT(attr->it_caps != NULL);

	switch (attr->type) {
	/* All known non-native transports here; for now, iSER */
	case IDM_TRANSPORT_TYPE_ISER:
		idm_transport_list[attr->type].it_ops	= attr->it_ops;
		idm_transport_list[attr->type].it_caps	= attr->it_caps;
		return (IDM_STATUS_SUCCESS);

	default:
		cmn_err(CE_NOTE, "idm: unknown transport type (0x%x) in "
		    "idm_transport_register", attr->type);
		return (IDM_STATUS_SUCCESS);
	}
}

/*
 * idm_ini_conn_create
 *
 * This function is invoked by the iSCSI layer to create a connection context.
 * This does not actually establish the socket connection.
 *
 * cr - Connection request parameters
 * new_con - Output parameter that contains the new request if successful
 *
 */
idm_status_t
idm_ini_conn_create(idm_conn_req_t *cr, idm_conn_t **new_con)
{
	idm_transport_t		*it;
	idm_conn_t		*ic;
	int			rc;

	it = idm_transport_lookup(cr);

retry:
	ic = idm_conn_create_common(CONN_TYPE_INI, it->it_type,
	    &cr->icr_conn_ops);

	bcopy(&cr->cr_ini_dst_addr, &ic->ic_ini_dst_addr,
	    sizeof (cr->cr_ini_dst_addr));

	/* create the transport-specific connection components */
	rc = it->it_ops->it_ini_conn_create(cr, ic);
	if (rc != IDM_STATUS_SUCCESS) {
		/* cleanup the failed connection */
		idm_conn_destroy_common(ic);

		/*
		 * It is possible for an IB client to connect to
		 * an ethernet-only client via an IB-eth gateway.
		 * Therefore, if we are attempting to use iSER and
		 * fail, retry with sockets before ultimately
		 * failing the connection.
		 */
		if (it->it_type == IDM_TRANSPORT_TYPE_ISER) {
			it = &idm_transport_list[IDM_TRANSPORT_TYPE_SOCKETS];
			goto retry;
		}

		return (IDM_STATUS_FAIL);
	}

	*new_con = ic;

	mutex_enter(&idm.idm_global_mutex);
	list_insert_tail(&idm.idm_ini_conn_list, ic);
	mutex_exit(&idm.idm_global_mutex);

	return (IDM_STATUS_SUCCESS);
}

/*
 * idm_ini_conn_destroy
 *
 * Releases any resources associated with the connection.  This is the
 * complement to idm_ini_conn_create.
 * ic - idm_conn_t structure representing the relevant connection
 *
 */
void
idm_ini_conn_destroy_task(void *ic_void)
{
	idm_conn_t *ic = ic_void;

	ic->ic_transport_ops->it_ini_conn_destroy(ic);
	idm_conn_destroy_common(ic);
}

void
idm_ini_conn_destroy(idm_conn_t *ic)
{
	/*
	 * It's reasonable for the initiator to call idm_ini_conn_destroy
	 * from within the context of the CN_CONNECT_DESTROY notification.
	 * That's a problem since we want to destroy the taskq for the
	 * state machine associated with the connection.  Remove the
	 * connection from the list right away then handle the remaining
	 * work via the idm_global_taskq.
	 */
	mutex_enter(&idm.idm_global_mutex);
	list_remove(&idm.idm_ini_conn_list, ic);
	mutex_exit(&idm.idm_global_mutex);

	if (taskq_dispatch(idm.idm_global_taskq,
	    &idm_ini_conn_destroy_task, ic, TQ_SLEEP) == TASKQID_INVALID) {
		cmn_err(CE_WARN,
		    "idm_ini_conn_destroy: Couldn't dispatch task");
	}
}

/*
 * idm_ini_conn_connect
 *
 * Establish connection to the remote system identified in idm_conn_t.
 * The connection parameters including the remote IP address were established
 * in the call to idm_ini_conn_create.  The IDM state machine will
 * perform client notifications as necessary to prompt the initiator through
 * the login process.  IDM also keeps a timer running so that if the login
 * process doesn't complete in a timely manner it will fail.
 *
 * ic - idm_conn_t structure representing the relevant connection
 *
 * Returns success if the connection was established, otherwise some kind
 * of meaningful error code.
 *
 * Upon return the login has either failed or is loggin in (ffp)
 */
idm_status_t
idm_ini_conn_connect(idm_conn_t *ic)
{
	idm_status_t	rc;

	rc = idm_conn_sm_init(ic);
	if (rc != IDM_STATUS_SUCCESS) {
		return (ic->ic_conn_sm_status);
	}

	/* Hold connection until we return */
	idm_conn_hold(ic);

	/* Kick state machine */
	idm_conn_event(ic, CE_CONNECT_REQ, (uintptr_t)NULL);

	/* Wait for login flag */
	mutex_enter(&ic->ic_state_mutex);
	while (!(ic->ic_state_flags & CF_LOGIN_READY) &&
	    !(ic->ic_state_flags & CF_ERROR)) {
		cv_wait(&ic->ic_state_cv, &ic->ic_state_mutex);
	}

	/*
	 * The CN_READY_TO_LOGIN and/or the CN_CONNECT_FAIL call to
	 * idm_notify_client has already been generated by the idm conn
	 * state machine.  If connection fails any time after this
	 * check, we will detect it in iscsi_login.
	 */
	if (ic->ic_state_flags & CF_ERROR) {
		rc = ic->ic_conn_sm_status;
	}
	mutex_exit(&ic->ic_state_mutex);
	idm_conn_rele(ic);

	return (rc);
}

/*
 * idm_ini_conn_disconnect
 *
 * Forces a connection (previously established using idm_ini_conn_connect)
 * to perform a controlled shutdown, cleaning up any outstanding requests.
 *
 * ic - idm_conn_t structure representing the relevant connection
 *
 * This is asynchronous and will return before the connection is properly
 * shutdown
 */
/* ARGSUSED */
void
idm_ini_conn_disconnect(idm_conn_t *ic)
{
	idm_conn_event(ic, CE_TRANSPORT_FAIL, (uintptr_t)NULL);
}

/*
 * idm_ini_conn_disconnect_wait
 *
 * Forces a connection (previously established using idm_ini_conn_connect)
 * to perform a controlled shutdown.  Blocks until the connection is
 * disconnected.
 *
 * ic - idm_conn_t structure representing the relevant connection
 */
/* ARGSUSED */
void
idm_ini_conn_disconnect_sync(idm_conn_t *ic)
{
	mutex_enter(&ic->ic_state_mutex);
	if ((ic->ic_state != CS_S9_INIT_ERROR) &&
	    (ic->ic_state != CS_S11_COMPLETE)) {
		idm_conn_event_locked(ic, CE_TRANSPORT_FAIL, (uintptr_t)NULL,
		    CT_NONE);
		while ((ic->ic_state != CS_S9_INIT_ERROR) &&
		    (ic->ic_state != CS_S11_COMPLETE))
			cv_wait(&ic->ic_state_cv, &ic->ic_state_mutex);
	}
	mutex_exit(&ic->ic_state_mutex);
}

/*
 * idm_tgt_svc_create
 *
 * The target calls this service to obtain a service context for each available
 * transport, starting a service of each type related to the IP address and port
 * passed. The idm_svc_req_t contains the service parameters.
 */
idm_status_t
idm_tgt_svc_create(idm_svc_req_t *sr, idm_svc_t **new_svc)
{
	idm_transport_type_t	type;
	idm_transport_t		*it;
	idm_svc_t		*is;
	int			rc;

	*new_svc = NULL;
	is = kmem_zalloc(sizeof (idm_svc_t), KM_SLEEP);

	/* Initialize transport-agnostic components of the service handle */
	is->is_svc_req = *sr;
	mutex_init(&is->is_mutex, NULL, MUTEX_DEFAULT, NULL);
	cv_init(&is->is_cv, NULL, CV_DEFAULT, NULL);
	mutex_init(&is->is_count_mutex, NULL, MUTEX_DEFAULT, NULL);
	cv_init(&is->is_count_cv, NULL, CV_DEFAULT, NULL);
	idm_refcnt_init(&is->is_refcnt, is);

	/*
	 * Make sure all available transports are setup.  We call this now
	 * instead of at initialization time in case IB has become available
	 * since we started (hotplug, etc).
	 */
	idm_transport_setup(sr->sr_li, B_FALSE);

	/*
	 * Loop through the transports, configuring the transport-specific
	 * components of each one.
	 */
	for (type = 0; type < IDM_TRANSPORT_NUM_TYPES; type++) {

		it = &idm_transport_list[type];
		/*
		 * If it_ops is NULL then the transport is unconfigured
		 * and we shouldn't try to start the service.
		 */
		if (it->it_ops == NULL) {
			continue;
		}

		rc = it->it_ops->it_tgt_svc_create(sr, is);
		if (rc != IDM_STATUS_SUCCESS) {
			/* Teardown any configured services */
			while (type--) {
				it = &idm_transport_list[type];
				if (it->it_ops == NULL) {
					continue;
				}
				it->it_ops->it_tgt_svc_destroy(is);
			}
			/* Free the svc context and return */
			kmem_free(is, sizeof (idm_svc_t));
			return (rc);
		}
	}

	*new_svc = is;

	mutex_enter(&idm.idm_global_mutex);
	list_insert_tail(&idm.idm_tgt_svc_list, is);
	mutex_exit(&idm.idm_global_mutex);

	return (IDM_STATUS_SUCCESS);
}

/*
 * idm_tgt_svc_destroy
 *
 * is - idm_svc_t returned by the call to idm_tgt_svc_create
 *
 * Cleanup any resources associated with the idm_svc_t.
 */
void
idm_tgt_svc_destroy(idm_svc_t *is)
{
	idm_transport_type_t	type;
	idm_transport_t		*it;

	mutex_enter(&idm.idm_global_mutex);
	/* remove this service from the global list */
	list_remove(&idm.idm_tgt_svc_list, is);
	/* wakeup any waiters for service change */
	cv_broadcast(&idm.idm_tgt_svc_cv);
	mutex_exit(&idm.idm_global_mutex);

	/* teardown each transport-specific service */
	for (type = 0; type < IDM_TRANSPORT_NUM_TYPES; type++) {
		it = &idm_transport_list[type];
		if (it->it_ops == NULL) {
			continue;
		}

		it->it_ops->it_tgt_svc_destroy(is);
	}

	/* tear down the svc resources */
	idm_refcnt_destroy(&is->is_refcnt);
	cv_destroy(&is->is_count_cv);
	mutex_destroy(&is->is_count_mutex);
	cv_destroy(&is->is_cv);
	mutex_destroy(&is->is_mutex);

	/* free the svc handle */
	kmem_free(is, sizeof (idm_svc_t));
}

void
idm_tgt_svc_hold(idm_svc_t *is)
{
	idm_refcnt_hold(&is->is_refcnt);
}

void
idm_tgt_svc_rele_and_destroy(idm_svc_t *is)
{
	idm_refcnt_rele_and_destroy(&is->is_refcnt,
	    (idm_refcnt_cb_t *)&idm_tgt_svc_destroy);
}

/*
 * idm_tgt_svc_online
 *
 * is - idm_svc_t returned by the call to idm_tgt_svc_create
 *
 * Online each transport service, as we want this target to be accessible
 * via any configured transport.
 *
 * When the initiator establishes a new connection to the target, IDM will
 * call the "new connect" callback defined in the idm_svc_req_t structure
 * and it will pass an idm_conn_t structure representing that new connection.
 */
idm_status_t
idm_tgt_svc_online(idm_svc_t *is)
{

	idm_transport_type_t	type, last_type;
	idm_transport_t		*it;
	int			rc = IDM_STATUS_SUCCESS;

	mutex_enter(&is->is_mutex);
	if (is->is_online == 0) {
		/* Walk through each of the transports and online them */
		for (type = 0; type < IDM_TRANSPORT_NUM_TYPES; type++) {
			it = &idm_transport_list[type];
			if (it->it_ops == NULL) {
				/* transport is not registered */
				continue;
			}

			mutex_exit(&is->is_mutex);
			rc = it->it_ops->it_tgt_svc_online(is);
			mutex_enter(&is->is_mutex);
			if (rc != IDM_STATUS_SUCCESS) {
				last_type = type;
				break;
			}
		}
		if (rc != IDM_STATUS_SUCCESS) {
			/*
			 * The last transport failed to online.
			 * Offline any transport onlined above and
			 * do not online the target.
			 */
			for (type = 0; type < last_type; type++) {
				it = &idm_transport_list[type];
				if (it->it_ops == NULL) {
					/* transport is not registered */
					continue;
				}

				mutex_exit(&is->is_mutex);
				it->it_ops->it_tgt_svc_offline(is);
				mutex_enter(&is->is_mutex);
			}
		} else {
			/* Target service now online */
			is->is_online = 1;
		}
	} else {
		/* Target service already online, just bump the count */
		is->is_online++;
	}
	mutex_exit(&is->is_mutex);

	return (rc);
}

/*
 * idm_tgt_svc_offline
 *
 * is - idm_svc_t returned by the call to idm_tgt_svc_create
 *
 * Shutdown any online target services.
 */
void
idm_tgt_svc_offline(idm_svc_t *is)
{
	idm_transport_type_t	type;
	idm_transport_t		*it;

	mutex_enter(&is->is_mutex);
	is->is_online--;
	if (is->is_online == 0) {
		/* Walk through each of the transports and offline them */
		for (type = 0; type < IDM_TRANSPORT_NUM_TYPES; type++) {
			it = &idm_transport_list[type];
			if (it->it_ops == NULL) {
				/* transport is not registered */
				continue;
			}

			mutex_exit(&is->is_mutex);
			it->it_ops->it_tgt_svc_offline(is);
			mutex_enter(&is->is_mutex);
		}
	}
	mutex_exit(&is->is_mutex);
}

/*
 * idm_tgt_svc_lookup
 *
 * Lookup a service instance listening on the specified port
 */

idm_svc_t *
idm_tgt_svc_lookup(uint16_t port)
{
	idm_svc_t *result;

retry:
	mutex_enter(&idm.idm_global_mutex);
	for (result = list_head(&idm.idm_tgt_svc_list);
	    result != NULL;
	    result = list_next(&idm.idm_tgt_svc_list, result)) {
		if (result->is_svc_req.sr_port == port) {
			if (result->is_online == 0) {
				/*
				 * A service exists on this port, but it
				 * is going away, wait for it to cleanup.
				 */
				cv_wait(&idm.idm_tgt_svc_cv,
				    &idm.idm_global_mutex);
				mutex_exit(&idm.idm_global_mutex);
				goto retry;
			}
			idm_tgt_svc_hold(result);
			mutex_exit(&idm.idm_global_mutex);
			return (result);
		}
	}
	mutex_exit(&idm.idm_global_mutex);

	return (NULL);
}

/*
 * idm_negotiate_key_values()
 * Give IDM level a chance to negotiate any login parameters it should own.
 *  -- leave unhandled parameters alone on request_nvl
 *  -- move all handled parameters to response_nvl with an appropriate response
 *  -- also add an entry to negotiated_nvl for any accepted parameters
 */
kv_status_t
idm_negotiate_key_values(idm_conn_t *ic, nvlist_t *request_nvl,
    nvlist_t *response_nvl, nvlist_t *negotiated_nvl)
{
	ASSERT(ic->ic_transport_ops != NULL);
	return (ic->ic_transport_ops->it_negotiate_key_values(ic,
	    request_nvl, response_nvl, negotiated_nvl));
}

/*
 * idm_notice_key_values()
 * Activate at the IDM level any parameters that have been negotiated.
 * Passes the set of key value pairs to the transport for activation.
 * This will be invoked as the connection is entering full-feature mode.
 */
void
idm_notice_key_values(idm_conn_t *ic, nvlist_t *negotiated_nvl)
{
	ASSERT(ic->ic_transport_ops != NULL);
	ic->ic_transport_ops->it_notice_key_values(ic, negotiated_nvl);
}

/*
 * idm_declare_key_values()
 * Activate an operational set of declarative parameters from the config_nvl,
 * and return the selected values in the outgoing_nvl.
 */
kv_status_t
idm_declare_key_values(idm_conn_t *ic, nvlist_t *config_nvl,
    nvlist_t *outgoing_nvl)
{
	ASSERT(ic->ic_transport_ops != NULL);
	return (ic->ic_transport_ops->it_declare_key_values(ic, config_nvl,
	    outgoing_nvl));
}

/*
 * idm_buf_tx_to_ini
 *
 * This is IDM's implementation of the 'Put_Data' operational primitive.
 *
 * This function is invoked by a target iSCSI layer to request its local
 * Datamover layer to transmit the Data-In PDU to the peer iSCSI layer
 * on the remote iSCSI node. The I/O buffer represented by 'idb' is
 * transferred to the initiator associated with task 'idt'. The connection
 * info, contents of the Data-In PDU header, the DataDescriptorIn, BHS,
 * and the callback (idb->idb_buf_cb) at transfer completion are
 * provided as input.
 *
 * This data transfer takes place transparently to the remote iSCSI layer,
 * i.e. without its participation.
 *
 * Using sockets, IDM implements the data transfer by segmenting the data
 * buffer into appropriately sized iSCSI PDUs and transmitting them to the
 * initiator. iSER performs the transfer using RDMA write.
 *
 */
idm_status_t
idm_buf_tx_to_ini(idm_task_t *idt, idm_buf_t *idb,
    uint32_t offset, uint32_t xfer_len,
    idm_buf_cb_t idb_buf_cb, void *cb_arg)
{
	idm_status_t rc;

	idb->idb_bufoffset = offset;
	idb->idb_xfer_len = xfer_len;
	idb->idb_buf_cb = idb_buf_cb;
	idb->idb_cb_arg = cb_arg;
	gethrestime(&idb->idb_xfer_start);

	/*
	 * Buffer should not contain the pattern.  If the pattern is
	 * present then we've been asked to transmit initialized data
	 */
	IDM_BUFPAT_CHECK(idb, xfer_len, BP_CHECK_ASSERT);

	mutex_enter(&idt->idt_mutex);
	switch (idt->idt_state) {
	case TASK_ACTIVE:
		idt->idt_tx_to_ini_start++;
		idm_task_hold(idt);
		idm_buf_bind_in_locked(idt, idb);
		idb->idb_in_transport = B_TRUE;
		rc = (*idt->idt_ic->ic_transport_ops->it_buf_tx_to_ini)
		    (idt, idb);
		return (rc);

	case TASK_SUSPENDING:
	case TASK_SUSPENDED:
		/*
		 * Bind buffer but don't start a transfer since the task
		 * is suspended
		 */
		idm_buf_bind_in_locked(idt, idb);
		mutex_exit(&idt->idt_mutex);
		return (IDM_STATUS_SUCCESS);

	case TASK_ABORTING:
	case TASK_ABORTED:
		/*
		 * Once the task is aborted, any buffers added to the
		 * idt_inbufv will never get cleaned up, so just return
		 * SUCCESS.  The buffer should get cleaned up by the
		 * client or framework once task_aborted has completed.
		 */
		mutex_exit(&idt->idt_mutex);
		return (IDM_STATUS_SUCCESS);

	default:
		ASSERT(0);
		break;
	}
	mutex_exit(&idt->idt_mutex);

	return (IDM_STATUS_FAIL);
}

/*
 * idm_buf_rx_from_ini
 *
 * This is IDM's implementation of the 'Get_Data' operational primitive.
 *
 * This function is invoked by a target iSCSI layer to request its local
 * Datamover layer to retrieve certain data identified by the R2T PDU from the
 * peer iSCSI layer on the remote node. The retrieved Data-Out PDU will be
 * mapped to the respective buffer by the task tags (ITT & TTT).
 * The connection information, contents of an R2T PDU, DataDescriptor, BHS, and
 * the callback (idb->idb_buf_cb) notification for data transfer completion are
 * are provided as input.
 *
 * When an iSCSI node sends an R2T PDU to its local Datamover layer, the local
 * Datamover layer, the local and remote Datamover layers transparently bring
 * about the data transfer requested by the R2T PDU, without the participation
 * of the iSCSI layers.
 *
 * Using sockets, IDM transmits an R2T PDU for each buffer and the rx_data_out()
 * assembles the Data-Out PDUs into the buffer. iSER uses RDMA read.
 *
 */
idm_status_t
idm_buf_rx_from_ini(idm_task_t *idt, idm_buf_t *idb,
    uint32_t offset, uint32_t xfer_len,
    idm_buf_cb_t idb_buf_cb, void *cb_arg)
{
	idm_status_t rc;

	idb->idb_bufoffset = offset;
	idb->idb_xfer_len = xfer_len;
	idb->idb_buf_cb = idb_buf_cb;
	idb->idb_cb_arg = cb_arg;
	gethrestime(&idb->idb_xfer_start);

	/*
	 * "In" buf list is for "Data In" PDU's, "Out" buf list is for
	 * "Data Out" PDU's
	 */
	mutex_enter(&idt->idt_mutex);
	switch (idt->idt_state) {
	case TASK_ACTIVE:
		idt->idt_rx_from_ini_start++;
		idm_task_hold(idt);
		idm_buf_bind_out_locked(idt, idb);
		idb->idb_in_transport = B_TRUE;
		rc = (*idt->idt_ic->ic_transport_ops->it_buf_rx_from_ini)
		    (idt, idb);
		return (rc);
	case TASK_SUSPENDING:
	case TASK_SUSPENDED:
	case TASK_ABORTING:
	case TASK_ABORTED:
		/*
		 * Bind buffer but don't start a transfer since the task
		 * is suspended
		 */
		idm_buf_bind_out_locked(idt, idb);
		mutex_exit(&idt->idt_mutex);
		return (IDM_STATUS_SUCCESS);
	default:
		ASSERT(0);
		break;
	}
	mutex_exit(&idt->idt_mutex);

	return (IDM_STATUS_FAIL);
}

/*
 * idm_buf_tx_to_ini_done
 *
 * The transport calls this after it has completed a transfer requested by
 * a call to transport_buf_tx_to_ini
 *
 * Caller holds idt->idt_mutex, idt->idt_mutex is released before returning.
 * idt may be freed after the call to idb->idb_buf_cb.
 */
void
idm_buf_tx_to_ini_done(idm_task_t *idt, idm_buf_t *idb, idm_status_t status)
{
	ASSERT(mutex_owned(&idt->idt_mutex));
	idb->idb_in_transport = B_FALSE;
	idb->idb_tx_thread = B_FALSE;
	idt->idt_tx_to_ini_done++;
	gethrestime(&idb->idb_xfer_done);

	/*
	 * idm_refcnt_rele may cause TASK_SUSPENDING --> TASK_SUSPENDED or
	 * TASK_ABORTING --> TASK_ABORTED transistion if the refcount goes
	 * to 0.
	 */
	idm_task_rele(idt);
	idb->idb_status = status;

	switch (idt->idt_state) {
	case TASK_ACTIVE:
		idt->idt_ic->ic_timestamp = ddi_get_lbolt();
		idm_buf_unbind_in_locked(idt, idb);
		mutex_exit(&idt->idt_mutex);
		(*idb->idb_buf_cb)(idb, status);
		return;
	case TASK_SUSPENDING:
	case TASK_SUSPENDED:
	case TASK_ABORTING:
	case TASK_ABORTED:
		/*
		 * To keep things simple we will ignore the case where the
		 * transfer was successful and leave all buffers bound to the
		 * task.  This allows us to also ignore the case where we've
		 * been asked to abort a task but the last transfer of the
		 * task has completed.  IDM has no idea whether this was, in
		 * fact, the last transfer of the task so it would be difficult
		 * to handle this case.  Everything should get sorted out again
		 * after task reassignment is complete.
		 *
		 * In the case of TASK_ABORTING we could conceivably call the
		 * buffer callback here but the timing of when the client's
		 * client_task_aborted callback is invoked vs. when the client's
		 * buffer callback gets invoked gets sticky.  We don't want
		 * the client to here from us again after the call to
		 * client_task_aborted() but we don't want to give it a bunch
		 * of failed buffer transfers until we've called
		 * client_task_aborted().  Instead we'll just leave all the
		 * buffers bound and allow the client to cleanup.
		 */
		break;
	default:
		ASSERT(0);
	}
	mutex_exit(&idt->idt_mutex);
}

/*
 * idm_buf_rx_from_ini_done
 *
 * The transport calls this after it has completed a transfer requested by
 * a call totransport_buf_tx_to_ini
 *
 * Caller holds idt->idt_mutex, idt->idt_mutex is released before returning.
 * idt may be freed after the call to idb->idb_buf_cb.
 */
void
idm_buf_rx_from_ini_done(idm_task_t *idt, idm_buf_t *idb, idm_status_t status)
{
	ASSERT(mutex_owned(&idt->idt_mutex));
	idb->idb_in_transport = B_FALSE;
	idt->idt_rx_from_ini_done++;
	gethrestime(&idb->idb_xfer_done);

	/*
	 * idm_refcnt_rele may cause TASK_SUSPENDING --> TASK_SUSPENDED or
	 * TASK_ABORTING --> TASK_ABORTED transistion if the refcount goes
	 * to 0.
	 */
	idm_task_rele(idt);
	idb->idb_status = status;

	if (status == IDM_STATUS_SUCCESS) {
		/*
		 * Buffer should not contain the pattern.  If it does then
		 * we did not get the data from the remote host.
		 */
		IDM_BUFPAT_CHECK(idb, idb->idb_xfer_len, BP_CHECK_ASSERT);
	}

	switch (idt->idt_state) {
	case TASK_ACTIVE:
		idt->idt_ic->ic_timestamp = ddi_get_lbolt();
		idm_buf_unbind_out_locked(idt, idb);
		mutex_exit(&idt->idt_mutex);
		(*idb->idb_buf_cb)(idb, status);
		return;
	case TASK_SUSPENDING:
	case TASK_SUSPENDED:
	case TASK_ABORTING:
	case TASK_ABORTED:
		/*
		 * To keep things simple we will ignore the case where the
		 * transfer was successful and leave all buffers bound to the
		 * task.  This allows us to also ignore the case where we've
		 * been asked to abort a task but the last transfer of the
		 * task has completed.  IDM has no idea whether this was, in
		 * fact, the last transfer of the task so it would be difficult
		 * to handle this case.  Everything should get sorted out again
		 * after task reassignment is complete.
		 *
		 * In the case of TASK_ABORTING we could conceivably call the
		 * buffer callback here but the timing of when the client's
		 * client_task_aborted callback is invoked vs. when the client's
		 * buffer callback gets invoked gets sticky.  We don't want