Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3958 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
new file mode 100644
index 000000000..25e799dba
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -0,0 +1,3958 @@
+/*
+ * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
+ * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@acm.org>.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/ctype.h>
+#include <linux/kthread.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/atomic.h>
+#include <linux/inet.h>
+#include <rdma/ib_cache.h>
+#include <scsi/scsi_proto.h>
+#include <scsi/scsi_tcq.h>
+#include <target/target_core_base.h>
+#include <target/target_core_fabric.h>
+#include "ib_srpt.h"
+
+/* Name of this kernel module. */
+#define DRV_NAME		"ib_srpt"
+
+#define SRPT_ID_STRING	"Linux SRP target"
+
+#undef pr_fmt
+#define pr_fmt(fmt) DRV_NAME " " fmt
+
+MODULE_AUTHOR("Vu Pham and Bart Van Assche");
+MODULE_DESCRIPTION("SCSI RDMA Protocol target driver");
+MODULE_LICENSE("Dual BSD/GPL");
+
+/*
+ * Global Variables
+ */
+
+static u64 srpt_service_guid;
+static DEFINE_SPINLOCK(srpt_dev_lock);	/* Protects srpt_dev_list. */
+static LIST_HEAD(srpt_dev_list);	/* List of srpt_device structures. */
+
+static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
+module_param(srp_max_req_size, int, 0444);
+MODULE_PARM_DESC(srp_max_req_size,
+		 "Maximum size of SRP request messages in bytes.");
+
+static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
+module_param(srpt_srq_size, int, 0444);
+MODULE_PARM_DESC(srpt_srq_size,
+		 "Shared receive queue (SRQ) size.");
+
+static int srpt_get_u64_x(char *buffer, const struct kernel_param *kp)
+{
+	return sprintf(buffer, "0x%016llx\n", *(u64 *)kp->arg);
+}
+module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
+		  0444);
+MODULE_PARM_DESC(srpt_service_guid,
+		 "Using this value for ioc_guid, id_ext, and cm_listen_id instead of using the node_guid of the first HCA.");
+
+static struct ib_client srpt_client;
+/* Protects both rdma_cm_port and rdma_cm_id. */
+static DEFINE_MUTEX(rdma_cm_mutex);
+/* Port number RDMA/CM will bind to. */
+static u16 rdma_cm_port;
+static struct rdma_cm_id *rdma_cm_id;
+static void srpt_release_cmd(struct se_cmd *se_cmd);
+static void srpt_free_ch(struct kref *kref);
+static int srpt_queue_status(struct se_cmd *cmd);
+static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
+static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
+static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
+
+/*
+ * The only allowed channel state changes are those that change the channel
+ * state into a state with a higher numerical value. Hence the new > prev test.
+ */
+static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
+{
+	unsigned long flags;
+	enum rdma_ch_state prev;
+	bool changed = false;
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	prev = ch->state;
+	if (new > prev) {
+		ch->state = new;
+		changed = true;
+	}
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+
+	return changed;
+}
+
+/**
+ * srpt_event_handler - asynchronous IB event callback function
+ * @handler: IB event handler registered by ib_register_event_handler().
+ * @event: Description of the event that occurred.
+ *
+ * Callback function called by the InfiniBand core when an asynchronous IB
+ * event occurs. This callback may occur in interrupt context. See also
+ * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
+ * Architecture Specification.
+ */
+static void srpt_event_handler(struct ib_event_handler *handler,
+			       struct ib_event *event)
+{
+	struct srpt_device *sdev =
+		container_of(handler, struct srpt_device, event_handler);
+	struct srpt_port *sport;
+	u8 port_num;
+
+	pr_debug("ASYNC event= %d on device= %s\n", event->event,
+		 dev_name(&sdev->device->dev));
+
+	switch (event->event) {
+	case IB_EVENT_PORT_ERR:
+		port_num = event->element.port_num - 1;
+		if (port_num < sdev->device->phys_port_cnt) {
+			sport = &sdev->port[port_num];
+			sport->lid = 0;
+			sport->sm_lid = 0;
+		} else {
+			WARN(true, "event %d: port_num %d out of range 1..%d\n",
+			     event->event, port_num + 1,
+			     sdev->device->phys_port_cnt);
+		}
+		break;
+	case IB_EVENT_PORT_ACTIVE:
+	case IB_EVENT_LID_CHANGE:
+	case IB_EVENT_PKEY_CHANGE:
+	case IB_EVENT_SM_CHANGE:
+	case IB_EVENT_CLIENT_REREGISTER:
+	case IB_EVENT_GID_CHANGE:
+		/* Refresh port data asynchronously. */
+		port_num = event->element.port_num - 1;
+		if (port_num < sdev->device->phys_port_cnt) {
+			sport = &sdev->port[port_num];
+			if (!sport->lid && !sport->sm_lid)
+				schedule_work(&sport->work);
+		} else {
+			WARN(true, "event %d: port_num %d out of range 1..%d\n",
+			     event->event, port_num + 1,
+			     sdev->device->phys_port_cnt);
+		}
+		break;
+	default:
+		pr_err("received unrecognized IB event %d\n", event->event);
+		break;
+	}
+}
+
+/**
+ * srpt_srq_event - SRQ event callback function
+ * @event: Description of the event that occurred.
+ * @ctx: Context pointer specified at SRQ creation time.
+ */
+static void srpt_srq_event(struct ib_event *event, void *ctx)
+{
+	pr_debug("SRQ event %d\n", event->event);
+}
+
+static const char *get_ch_state_name(enum rdma_ch_state s)
+{
+	switch (s) {
+	case CH_CONNECTING:
+		return "connecting";
+	case CH_LIVE:
+		return "live";
+	case CH_DISCONNECTING:
+		return "disconnecting";
+	case CH_DRAINING:
+		return "draining";
+	case CH_DISCONNECTED:
+		return "disconnected";
+	}
+	return "???";
+}
+
+/**
+ * srpt_qp_event - QP event callback function
+ * @event: Description of the event that occurred.
+ * @ch: SRPT RDMA channel.
+ */
+static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
+{
+	pr_debug("QP event %d on ch=%p sess_name=%s-%d state=%s\n",
+		 event->event, ch, ch->sess_name, ch->qp->qp_num,
+		 get_ch_state_name(ch->state));
+
+	switch (event->event) {
+	case IB_EVENT_COMM_EST:
+		if (ch->using_rdma_cm)
+			rdma_notify(ch->rdma_cm.cm_id, event->event);
+		else
+			ib_cm_notify(ch->ib_cm.cm_id, event->event);
+		break;
+	case IB_EVENT_QP_LAST_WQE_REACHED:
+		pr_debug("%s-%d, state %s: received Last WQE event.\n",
+			 ch->sess_name, ch->qp->qp_num,
+			 get_ch_state_name(ch->state));
+		break;
+	default:
+		pr_err("received unrecognized IB QP event %d\n", event->event);
+		break;
+	}
+}
+
+/**
+ * srpt_set_ioc - initialize a IOUnitInfo structure
+ * @c_list: controller list.
+ * @slot: one-based slot number.
+ * @value: four-bit value.
+ *
+ * Copies the lowest four bits of value in element slot of the array of four
+ * bit elements called c_list (controller list). The index slot is one-based.
+ */
+static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
+{
+	u16 id;
+	u8 tmp;
+
+	id = (slot - 1) / 2;
+	if (slot & 0x1) {
+		tmp = c_list[id] & 0xf;
+		c_list[id] = (value << 4) | tmp;
+	} else {
+		tmp = c_list[id] & 0xf0;
+		c_list[id] = (value & 0xf) | tmp;
+	}
+}
+
+/**
+ * srpt_get_class_port_info - copy ClassPortInfo to a management datagram
+ * @mad: Datagram that will be sent as response to DM_ATTR_CLASS_PORT_INFO.
+ *
+ * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
+ * Specification.
+ */
+static void srpt_get_class_port_info(struct ib_dm_mad *mad)
+{
+	struct ib_class_port_info *cif;
+
+	cif = (struct ib_class_port_info *)mad->data;
+	memset(cif, 0, sizeof(*cif));
+	cif->base_version = 1;
+	cif->class_version = 1;
+
+	ib_set_cpi_resp_time(cif, 20);
+	mad->mad_hdr.status = 0;
+}
+
+/**
+ * srpt_get_iou - write IOUnitInfo to a management datagram
+ * @mad: Datagram that will be sent as response to DM_ATTR_IOU_INFO.
+ *
+ * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
+ * Specification. See also section B.7, table B.6 in the SRP r16a document.
+ */
+static void srpt_get_iou(struct ib_dm_mad *mad)
+{
+	struct ib_dm_iou_info *ioui;
+	u8 slot;
+	int i;
+
+	ioui = (struct ib_dm_iou_info *)mad->data;
+	ioui->change_id = cpu_to_be16(1);
+	ioui->max_controllers = 16;
+
+	/* set present for slot 1 and empty for the rest */
+	srpt_set_ioc(ioui->controller_list, 1, 1);
+	for (i = 1, slot = 2; i < 16; i++, slot++)
+		srpt_set_ioc(ioui->controller_list, slot, 0);
+
+	mad->mad_hdr.status = 0;
+}
+
+/**
+ * srpt_get_ioc - write IOControllerprofile to a management datagram
+ * @sport: HCA port through which the MAD has been received.
+ * @slot: Slot number specified in DM_ATTR_IOC_PROFILE query.
+ * @mad: Datagram that will be sent as response to DM_ATTR_IOC_PROFILE.
+ *
+ * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
+ * Architecture Specification. See also section B.7, table B.7 in the SRP
+ * r16a document.
+ */
+static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
+			 struct ib_dm_mad *mad)
+{
+	struct srpt_device *sdev = sport->sdev;
+	struct ib_dm_ioc_profile *iocp;
+	int send_queue_depth;
+
+	iocp = (struct ib_dm_ioc_profile *)mad->data;
+
+	if (!slot || slot > 16) {
+		mad->mad_hdr.status
+			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
+		return;
+	}
+
+	if (slot > 2) {
+		mad->mad_hdr.status
+			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
+		return;
+	}
+
+	if (sdev->use_srq)
+		send_queue_depth = sdev->srq_size;
+	else
+		send_queue_depth = min(MAX_SRPT_RQ_SIZE,
+				       sdev->device->attrs.max_qp_wr);
+
+	memset(iocp, 0, sizeof(*iocp));
+	strcpy(iocp->id_string, SRPT_ID_STRING);
+	iocp->guid = cpu_to_be64(srpt_service_guid);
+	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
+	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
+	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
+	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
+	iocp->subsys_device_id = 0x0;
+	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
+	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
+	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
+	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
+	iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
+	iocp->rdma_read_depth = 4;
+	iocp->send_size = cpu_to_be32(srp_max_req_size);
+	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
+					  1U << 24));
+	iocp->num_svc_entries = 1;
+	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
+		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
+
+	mad->mad_hdr.status = 0;
+}
+
+/**
+ * srpt_get_svc_entries - write ServiceEntries to a management datagram
+ * @ioc_guid: I/O controller GUID to use in reply.
+ * @slot: I/O controller number.
+ * @hi: End of the range of service entries to be specified in the reply.
+ * @lo: Start of the range of service entries to be specified in the reply..
+ * @mad: Datagram that will be sent as response to DM_ATTR_SVC_ENTRIES.
+ *
+ * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
+ * Specification. See also section B.7, table B.8 in the SRP r16a document.
+ */
+static void srpt_get_svc_entries(u64 ioc_guid,
+				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
+{
+	struct ib_dm_svc_entries *svc_entries;
+
+	WARN_ON(!ioc_guid);
+
+	if (!slot || slot > 16) {
+		mad->mad_hdr.status
+			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
+		return;
+	}
+
+	if (slot > 2 || lo > hi || hi > 1) {
+		mad->mad_hdr.status
+			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
+		return;
+	}
+
+	svc_entries = (struct ib_dm_svc_entries *)mad->data;
+	memset(svc_entries, 0, sizeof(*svc_entries));
+	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
+	snprintf(svc_entries->service_entries[0].name,
+		 sizeof(svc_entries->service_entries[0].name),
+		 "%s%016llx",
+		 SRP_SERVICE_NAME_PREFIX,
+		 ioc_guid);
+
+	mad->mad_hdr.status = 0;
+}
+
+/**
+ * srpt_mgmt_method_get - process a received management datagram
+ * @sp:      HCA port through which the MAD has been received.
+ * @rq_mad:  received MAD.
+ * @rsp_mad: response MAD.
+ */
+static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
+				 struct ib_dm_mad *rsp_mad)
+{
+	u16 attr_id;
+	u32 slot;
+	u8 hi, lo;
+
+	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
+	switch (attr_id) {
+	case DM_ATTR_CLASS_PORT_INFO:
+		srpt_get_class_port_info(rsp_mad);
+		break;
+	case DM_ATTR_IOU_INFO:
+		srpt_get_iou(rsp_mad);
+		break;
+	case DM_ATTR_IOC_PROFILE:
+		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
+		srpt_get_ioc(sp, slot, rsp_mad);
+		break;
+	case DM_ATTR_SVC_ENTRIES:
+		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
+		hi = (u8) ((slot >> 8) & 0xff);
+		lo = (u8) (slot & 0xff);
+		slot = (u16) ((slot >> 16) & 0xffff);
+		srpt_get_svc_entries(srpt_service_guid,
+				     slot, hi, lo, rsp_mad);
+		break;
+	default:
+		rsp_mad->mad_hdr.status =
+		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
+		break;
+	}
+}
+
+/**
+ * srpt_mad_send_handler - MAD send completion callback
+ * @mad_agent: Return value of ib_register_mad_agent().
+ * @mad_wc: Work completion reporting that the MAD has been sent.
+ */
+static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
+				  struct ib_mad_send_wc *mad_wc)
+{
+	rdma_destroy_ah(mad_wc->send_buf->ah, RDMA_DESTROY_AH_SLEEPABLE);
+	ib_free_send_mad(mad_wc->send_buf);
+}
+
+/**
+ * srpt_mad_recv_handler - MAD reception callback function
+ * @mad_agent: Return value of ib_register_mad_agent().
+ * @send_buf: Not used.
+ * @mad_wc: Work completion reporting that a MAD has been received.
+ */
+static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
+				  struct ib_mad_send_buf *send_buf,
+				  struct ib_mad_recv_wc *mad_wc)
+{
+	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
+	struct ib_ah *ah;
+	struct ib_mad_send_buf *rsp;
+	struct ib_dm_mad *dm_mad;
+
+	if (!mad_wc || !mad_wc->recv_buf.mad)
+		return;
+
+	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
+				  mad_wc->recv_buf.grh, mad_agent->port_num);
+	if (IS_ERR(ah))
+		goto err;
+
+	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
+
+	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
+				 mad_wc->wc->pkey_index, 0,
+				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
+				 GFP_KERNEL,
+				 IB_MGMT_BASE_VERSION);
+	if (IS_ERR(rsp))
+		goto err_rsp;
+
+	rsp->ah = ah;
+
+	dm_mad = rsp->mad;
+	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
+	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
+	dm_mad->mad_hdr.status = 0;
+
+	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
+	case IB_MGMT_METHOD_GET:
+		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
+		break;
+	case IB_MGMT_METHOD_SET:
+		dm_mad->mad_hdr.status =
+		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
+		break;
+	default:
+		dm_mad->mad_hdr.status =
+		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
+		break;
+	}
+
+	if (!ib_post_send_mad(rsp, NULL)) {
+		ib_free_recv_mad(mad_wc);
+		/* will destroy_ah & free_send_mad in send completion */
+		return;
+	}
+
+	ib_free_send_mad(rsp);
+
+err_rsp:
+	rdma_destroy_ah(ah, RDMA_DESTROY_AH_SLEEPABLE);
+err:
+	ib_free_recv_mad(mad_wc);
+}
+
+static int srpt_format_guid(char *buf, unsigned int size, const __be64 *guid)
+{
+	const __be16 *g = (const __be16 *)guid;
+
+	return snprintf(buf, size, "%04x:%04x:%04x:%04x",
+			be16_to_cpu(g[0]), be16_to_cpu(g[1]),
+			be16_to_cpu(g[2]), be16_to_cpu(g[3]));
+}
+
+/**
+ * srpt_refresh_port - configure a HCA port
+ * @sport: SRPT HCA port.
+ *
+ * Enable InfiniBand management datagram processing, update the cached sm_lid,
+ * lid and gid values, and register a callback function for processing MADs
+ * on the specified port.
+ *
+ * Note: It is safe to call this function more than once for the same port.
+ */
+static int srpt_refresh_port(struct srpt_port *sport)
+{
+	struct ib_mad_agent *mad_agent;
+	struct ib_mad_reg_req reg_req;
+	struct ib_port_modify port_modify;
+	struct ib_port_attr port_attr;
+	int ret;
+
+	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
+	if (ret)
+		return ret;
+
+	sport->sm_lid = port_attr.sm_lid;
+	sport->lid = port_attr.lid;
+
+	ret = rdma_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
+	if (ret)
+		return ret;
+
+	srpt_format_guid(sport->guid_name, ARRAY_SIZE(sport->guid_name),
+			 &sport->gid.global.interface_id);
+	snprintf(sport->gid_name, ARRAY_SIZE(sport->gid_name),
+		 "0x%016llx%016llx",
+		 be64_to_cpu(sport->gid.global.subnet_prefix),
+		 be64_to_cpu(sport->gid.global.interface_id));
+
+	if (rdma_protocol_iwarp(sport->sdev->device, sport->port))
+		return 0;
+
+	memset(&port_modify, 0, sizeof(port_modify));
+	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
+	port_modify.clr_port_cap_mask = 0;
+
+	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
+	if (ret) {
+		pr_warn("%s-%d: enabling device management failed (%d). Note: this is expected if SR-IOV is enabled.\n",
+			dev_name(&sport->sdev->device->dev), sport->port, ret);
+		return 0;
+	}
+
+	if (!sport->mad_agent) {
+		memset(&reg_req, 0, sizeof(reg_req));
+		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
+		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
+		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
+		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
+
+		mad_agent = ib_register_mad_agent(sport->sdev->device,
+						  sport->port,
+						  IB_QPT_GSI,
+						  &reg_req, 0,
+						  srpt_mad_send_handler,
+						  srpt_mad_recv_handler,
+						  sport, 0);
+		if (IS_ERR(mad_agent)) {
+			pr_err("%s-%d: MAD agent registration failed (%ld). Note: this is expected if SR-IOV is enabled.\n",
+			       dev_name(&sport->sdev->device->dev), sport->port,
+			       PTR_ERR(mad_agent));
+			sport->mad_agent = NULL;
+			memset(&port_modify, 0, sizeof(port_modify));
+			port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
+			ib_modify_port(sport->sdev->device, sport->port, 0,
+				       &port_modify);
+			return 0;
+		}
+
+		sport->mad_agent = mad_agent;
+	}
+
+	return 0;
+}
+
+/**
+ * srpt_unregister_mad_agent - unregister MAD callback functions
+ * @sdev: SRPT HCA pointer.
+ * @port_cnt: number of ports with registered MAD
+ *
+ * Note: It is safe to call this function more than once for the same device.
+ */
+static void srpt_unregister_mad_agent(struct srpt_device *sdev, int port_cnt)
+{
+	struct ib_port_modify port_modify = {
+		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
+	};
+	struct srpt_port *sport;
+	int i;
+
+	for (i = 1; i <= port_cnt; i++) {
+		sport = &sdev->port[i - 1];
+		WARN_ON(sport->port != i);
+		if (sport->mad_agent) {
+			ib_modify_port(sdev->device, i, 0, &port_modify);
+			ib_unregister_mad_agent(sport->mad_agent);
+			sport->mad_agent = NULL;
+		}
+	}
+}
+
+/**
+ * srpt_alloc_ioctx - allocate a SRPT I/O context structure
+ * @sdev: SRPT HCA pointer.
+ * @ioctx_size: I/O context size.
+ * @buf_cache: I/O buffer cache.
+ * @dir: DMA data direction.
+ */
+static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
+					   int ioctx_size,
+					   struct kmem_cache *buf_cache,
+					   enum dma_data_direction dir)
+{
+	struct srpt_ioctx *ioctx;
+
+	ioctx = kzalloc(ioctx_size, GFP_KERNEL);
+	if (!ioctx)
+		goto err;
+
+	ioctx->buf = kmem_cache_alloc(buf_cache, GFP_KERNEL);
+	if (!ioctx->buf)
+		goto err_free_ioctx;
+
+	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf,
+				       kmem_cache_size(buf_cache), dir);
+	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
+		goto err_free_buf;
+
+	return ioctx;
+
+err_free_buf:
+	kmem_cache_free(buf_cache, ioctx->buf);
+err_free_ioctx:
+	kfree(ioctx);
+err:
+	return NULL;
+}
+
+/**
+ * srpt_free_ioctx - free a SRPT I/O context structure
+ * @sdev: SRPT HCA pointer.
+ * @ioctx: I/O context pointer.
+ * @buf_cache: I/O buffer cache.
+ * @dir: DMA data direction.
+ */
+static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
+			    struct kmem_cache *buf_cache,
+			    enum dma_data_direction dir)
+{
+	if (!ioctx)
+		return;
+
+	ib_dma_unmap_single(sdev->device, ioctx->dma,
+			    kmem_cache_size(buf_cache), dir);
+	kmem_cache_free(buf_cache, ioctx->buf);
+	kfree(ioctx);
+}
+
+/**
+ * srpt_alloc_ioctx_ring - allocate a ring of SRPT I/O context structures
+ * @sdev:       Device to allocate the I/O context ring for.
+ * @ring_size:  Number of elements in the I/O context ring.
+ * @ioctx_size: I/O context size.
+ * @buf_cache:  I/O buffer cache.
+ * @alignment_offset: Offset in each ring buffer at which the SRP information
+ *		unit starts.
+ * @dir:        DMA data direction.
+ */
+static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
+				int ring_size, int ioctx_size,
+				struct kmem_cache *buf_cache,
+				int alignment_offset,
+				enum dma_data_direction dir)
+{
+	struct srpt_ioctx **ring;
+	int i;
+
+	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx) &&
+		ioctx_size != sizeof(struct srpt_send_ioctx));
+
+	ring = kvmalloc_array(ring_size, sizeof(ring[0]), GFP_KERNEL);
+	if (!ring)
+		goto out;
+	for (i = 0; i < ring_size; ++i) {
+		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, buf_cache, dir);
+		if (!ring[i])
+			goto err;
+		ring[i]->index = i;
+		ring[i]->offset = alignment_offset;
+	}
+	goto out;
+
+err:
+	while (--i >= 0)
+		srpt_free_ioctx(sdev, ring[i], buf_cache, dir);
+	kvfree(ring);
+	ring = NULL;
+out:
+	return ring;
+}
+
+/**
+ * srpt_free_ioctx_ring - free the ring of SRPT I/O context structures
+ * @ioctx_ring: I/O context ring to be freed.
+ * @sdev: SRPT HCA pointer.
+ * @ring_size: Number of ring elements.
+ * @buf_cache: I/O buffer cache.
+ * @dir: DMA data direction.
+ */
+static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
+				 struct srpt_device *sdev, int ring_size,
+				 struct kmem_cache *buf_cache,
+				 enum dma_data_direction dir)
+{
+	int i;
+
+	if (!ioctx_ring)
+		return;
+
+	for (i = 0; i < ring_size; ++i)
+		srpt_free_ioctx(sdev, ioctx_ring[i], buf_cache, dir);
+	kvfree(ioctx_ring);
+}
+
+/**
+ * srpt_set_cmd_state - set the state of a SCSI command
+ * @ioctx: Send I/O context.
+ * @new: New I/O context state.
+ *
+ * Does not modify the state of aborted commands. Returns the previous command
+ * state.
+ */
+static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
+						  enum srpt_command_state new)
+{
+	enum srpt_command_state previous;
+
+	previous = ioctx->state;
+	if (previous != SRPT_STATE_DONE)
+		ioctx->state = new;
+
+	return previous;
+}
+
+/**
+ * srpt_test_and_set_cmd_state - test and set the state of a command
+ * @ioctx: Send I/O context.
+ * @old: Current I/O context state.
+ * @new: New I/O context state.
+ *
+ * Returns true if and only if the previous command state was equal to 'old'.
+ */
+static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
+					enum srpt_command_state old,
+					enum srpt_command_state new)
+{
+	enum srpt_command_state previous;
+
+	WARN_ON(!ioctx);
+	WARN_ON(old == SRPT_STATE_DONE);
+	WARN_ON(new == SRPT_STATE_NEW);
+
+	previous = ioctx->state;
+	if (previous == old)
+		ioctx->state = new;
+
+	return previous == old;
+}
+
+/**
+ * srpt_post_recv - post an IB receive request
+ * @sdev: SRPT HCA pointer.
+ * @ch: SRPT RDMA channel.
+ * @ioctx: Receive I/O context pointer.
+ */
+static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
+			  struct srpt_recv_ioctx *ioctx)
+{
+	struct ib_sge list;
+	struct ib_recv_wr wr;
+
+	BUG_ON(!sdev);
+	list.addr = ioctx->ioctx.dma + ioctx->ioctx.offset;
+	list.length = srp_max_req_size;
+	list.lkey = sdev->lkey;
+
+	ioctx->ioctx.cqe.done = srpt_recv_done;
+	wr.wr_cqe = &ioctx->ioctx.cqe;
+	wr.next = NULL;
+	wr.sg_list = &list;
+	wr.num_sge = 1;
+
+	if (sdev->use_srq)
+		return ib_post_srq_recv(sdev->srq, &wr, NULL);
+	else
+		return ib_post_recv(ch->qp, &wr, NULL);
+}
+
+/**
+ * srpt_zerolength_write - perform a zero-length RDMA write
+ * @ch: SRPT RDMA channel.
+ *
+ * A quote from the InfiniBand specification: C9-88: For an HCA responder
+ * using Reliable Connection service, for each zero-length RDMA READ or WRITE
+ * request, the R_Key shall not be validated, even if the request includes
+ * Immediate data.
+ */
+static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
+{
+	struct ib_rdma_wr wr = {
+		.wr = {
+			.next		= NULL,
+			{ .wr_cqe	= &ch->zw_cqe, },
+			.opcode		= IB_WR_RDMA_WRITE,
+			.send_flags	= IB_SEND_SIGNALED,
+		}
+	};
+
+	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
+		 ch->qp->qp_num);
+
+	return ib_post_send(ch->qp, &wr.wr, NULL);
+}
+
+static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct srpt_rdma_ch *ch = wc->qp->qp_context;
+
+	pr_debug("%s-%d wc->status %d\n", ch->sess_name, ch->qp->qp_num,
+		 wc->status);
+
+	if (wc->status == IB_WC_SUCCESS) {
+		srpt_process_wait_list(ch);
+	} else {
+		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
+			schedule_work(&ch->release_work);
+		else
+			pr_debug("%s-%d: already disconnected.\n",
+				 ch->sess_name, ch->qp->qp_num);
+	}
+}
+
+static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
+		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
+		unsigned *sg_cnt)
+{
+	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
+	struct srpt_rdma_ch *ch = ioctx->ch;
+	struct scatterlist *prev = NULL;
+	unsigned prev_nents;
+	int ret, i;
+
+	if (nbufs == 1) {
+		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
+	} else {
+		ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
+			GFP_KERNEL);
+		if (!ioctx->rw_ctxs)
+			return -ENOMEM;
+	}
+
+	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
+		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
+		u64 remote_addr = be64_to_cpu(db->va);
+		u32 size = be32_to_cpu(db->len);
+		u32 rkey = be32_to_cpu(db->key);
+
+		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
+				i < nbufs - 1);
+		if (ret)
+			goto unwind;
+
+		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
+				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
+		if (ret < 0) {
+			target_free_sgl(ctx->sg, ctx->nents);
+			goto unwind;
+		}
+
+		ioctx->n_rdma += ret;
+		ioctx->n_rw_ctx++;
+
+		if (prev) {
+			sg_unmark_end(&prev[prev_nents - 1]);
+			sg_chain(prev, prev_nents + 1, ctx->sg);
+		} else {
+			*sg = ctx->sg;
+		}
+
+		prev = ctx->sg;
+		prev_nents = ctx->nents;
+
+		*sg_cnt += ctx->nents;
+	}
+
+	return 0;
+
+unwind:
+	while (--i >= 0) {
+		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
+
+		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
+				ctx->sg, ctx->nents, dir);
+		target_free_sgl(ctx->sg, ctx->nents);
+	}
+	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
+		kfree(ioctx->rw_ctxs);
+	return ret;
+}
+
+static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
+				    struct srpt_send_ioctx *ioctx)
+{
+	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
+	int i;
+
+	for (i = 0; i < ioctx->n_rw_ctx; i++) {
+		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
+
+		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
+				ctx->sg, ctx->nents, dir);
+		target_free_sgl(ctx->sg, ctx->nents);
+	}
+
+	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
+		kfree(ioctx->rw_ctxs);
+}
+
+static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
+{
+	/*
+	 * The pointer computations below will only be compiled correctly
+	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
+	 * whether srp_cmd::add_data has been declared as a byte pointer.
+	 */
+	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
+		     !__same_type(srp_cmd->add_data[0], (u8)0));
+
+	/*
+	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
+	 * CDB LENGTH' field are reserved and the size in bytes of this field
+	 * is four times the value specified in bits 3..7. Hence the "& ~3".
+	 */
+	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
+}
+
+/**
+ * srpt_get_desc_tbl - parse the data descriptors of a SRP_CMD request
+ * @recv_ioctx: I/O context associated with the received command @srp_cmd.
+ * @ioctx: I/O context that will be used for responding to the initiator.
+ * @srp_cmd: Pointer to the SRP_CMD request data.
+ * @dir: Pointer to the variable to which the transfer direction will be
+ *   written.
+ * @sg: [out] scatterlist for the parsed SRP_CMD.
+ * @sg_cnt: [out] length of @sg.
+ * @data_len: Pointer to the variable to which the total data length of all
+ *   descriptors in the SRP_CMD request will be written.
+ * @imm_data_offset: [in] Offset in SRP_CMD requests at which immediate data
+ *   starts.
+ *
+ * This function initializes ioctx->nrbuf and ioctx->r_bufs.
+ *
+ * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
+ * -ENOMEM when memory allocation fails and zero upon success.
+ */
+static int srpt_get_desc_tbl(struct srpt_recv_ioctx *recv_ioctx,
+		struct srpt_send_ioctx *ioctx,
+		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
+		struct scatterlist **sg, unsigned int *sg_cnt, u64 *data_len,
+		u16 imm_data_offset)
+{
+	BUG_ON(!dir);
+	BUG_ON(!data_len);
+
+	/*
+	 * The lower four bits of the buffer format field contain the DATA-IN
+	 * buffer descriptor format, and the highest four bits contain the
+	 * DATA-OUT buffer descriptor format.
+	 */
+	if (srp_cmd->buf_fmt & 0xf)
+		/* DATA-IN: transfer data from target to initiator (read). */
+		*dir = DMA_FROM_DEVICE;
+	else if (srp_cmd->buf_fmt >> 4)
+		/* DATA-OUT: transfer data from initiator to target (write). */
+		*dir = DMA_TO_DEVICE;
+	else
+		*dir = DMA_NONE;
+
+	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
+	ioctx->cmd.data_direction = *dir;
+
+	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
+	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
+		struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
+
+		*data_len = be32_to_cpu(db->len);
+		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
+	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
+		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
+		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
+		int nbufs = be32_to_cpu(idb->table_desc.len) /
+				sizeof(struct srp_direct_buf);
+
+		if (nbufs >
+		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
+			pr_err("received unsupported SRP_CMD request type (%u out + %u in != %u / %zu)\n",
+			       srp_cmd->data_out_desc_cnt,
+			       srp_cmd->data_in_desc_cnt,
+			       be32_to_cpu(idb->table_desc.len),
+			       sizeof(struct srp_direct_buf));
+			return -EINVAL;
+		}
+
+		*data_len = be32_to_cpu(idb->len);
+		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
+				sg, sg_cnt);
+	} else if ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_IMM) {
+		struct srp_imm_buf *imm_buf = srpt_get_desc_buf(srp_cmd);
+		void *data = (void *)srp_cmd + imm_data_offset;
+		uint32_t len = be32_to_cpu(imm_buf->len);
+		uint32_t req_size = imm_data_offset + len;
+
+		if (req_size > srp_max_req_size) {
+			pr_err("Immediate data (length %d + %d) exceeds request size %d\n",
+			       imm_data_offset, len, srp_max_req_size);
+			return -EINVAL;
+		}
+		if (recv_ioctx->byte_len < req_size) {
+			pr_err("Received too few data - %d < %d\n",
+			       recv_ioctx->byte_len, req_size);
+			return -EIO;
+		}
+		/*
+		 * The immediate data buffer descriptor must occur before the
+		 * immediate data itself.
+		 */
+		if ((void *)(imm_buf + 1) > (void *)data) {
+			pr_err("Received invalid write request\n");
+			return -EINVAL;
+		}
+		*data_len = len;
+		ioctx->recv_ioctx = recv_ioctx;
+		if ((uintptr_t)data & 511) {
+			pr_warn_once("Internal error - the receive buffers are not aligned properly.\n");
+			return -EINVAL;
+		}
+		sg_init_one(&ioctx->imm_sg, data, len);
+		*sg = &ioctx->imm_sg;
+		*sg_cnt = 1;
+		return 0;
+	} else {
+		*data_len = 0;
+		return 0;
+	}
+}
+
+/**
+ * srpt_init_ch_qp - initialize queue pair attributes
+ * @ch: SRPT RDMA channel.
+ * @qp: Queue pair pointer.
+ *
+ * Initialized the attributes of queue pair 'qp' by allowing local write,
+ * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
+ */
+static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
+{
+	struct ib_qp_attr *attr;
+	int ret;
+
+	WARN_ON_ONCE(ch->using_rdma_cm);
+
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (!attr)
+		return -ENOMEM;
+
+	attr->qp_state = IB_QPS_INIT;
+	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE;
+	attr->port_num = ch->sport->port;
+
+	ret = ib_find_cached_pkey(ch->sport->sdev->device, ch->sport->port,
+				  ch->pkey, &attr->pkey_index);
+	if (ret < 0)
+		pr_err("Translating pkey %#x failed (%d) - using index 0\n",
+		       ch->pkey, ret);
+
+	ret = ib_modify_qp(qp, attr,
+			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
+			   IB_QP_PKEY_INDEX);
+
+	kfree(attr);
+	return ret;
+}
+
+/**
+ * srpt_ch_qp_rtr - change the state of a channel to 'ready to receive' (RTR)
+ * @ch: channel of the queue pair.
+ * @qp: queue pair to change the state of.
+ *
+ * Returns zero upon success and a negative value upon failure.
+ *
+ * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
+ * If this structure ever becomes larger, it might be necessary to allocate
+ * it dynamically instead of on the stack.
+ */
+static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
+{
+	struct ib_qp_attr qp_attr;
+	int attr_mask;
+	int ret;
+
+	WARN_ON_ONCE(ch->using_rdma_cm);
+
+	qp_attr.qp_state = IB_QPS_RTR;
+	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
+	if (ret)
+		goto out;
+
+	qp_attr.max_dest_rd_atomic = 4;
+
+	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
+
+out:
+	return ret;
+}
+
+/**
+ * srpt_ch_qp_rts - change the state of a channel to 'ready to send' (RTS)
+ * @ch: channel of the queue pair.
+ * @qp: queue pair to change the state of.
+ *
+ * Returns zero upon success and a negative value upon failure.
+ *
+ * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
+ * If this structure ever becomes larger, it might be necessary to allocate
+ * it dynamically instead of on the stack.
+ */
+static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
+{
+	struct ib_qp_attr qp_attr;
+	int attr_mask;
+	int ret;
+
+	qp_attr.qp_state = IB_QPS_RTS;
+	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
+	if (ret)
+		goto out;
+
+	qp_attr.max_rd_atomic = 4;
+
+	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
+
+out:
+	return ret;
+}
+
+/**
+ * srpt_ch_qp_err - set the channel queue pair state to 'error'
+ * @ch: SRPT RDMA channel.
+ */
+static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
+{
+	struct ib_qp_attr qp_attr;
+
+	qp_attr.qp_state = IB_QPS_ERR;
+	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
+}
+
+/**
+ * srpt_get_send_ioctx - obtain an I/O context for sending to the initiator
+ * @ch: SRPT RDMA channel.
+ */
+static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
+{
+	struct srpt_send_ioctx *ioctx;
+	int tag, cpu;
+
+	BUG_ON(!ch);
+
+	tag = sbitmap_queue_get(&ch->sess->sess_tag_pool, &cpu);
+	if (tag < 0)
+		return NULL;
+
+	ioctx = ch->ioctx_ring[tag];
+	BUG_ON(ioctx->ch != ch);
+	ioctx->state = SRPT_STATE_NEW;
+	WARN_ON_ONCE(ioctx->recv_ioctx);
+	ioctx->n_rdma = 0;
+	ioctx->n_rw_ctx = 0;
+	ioctx->queue_status_only = false;
+	/*
+	 * transport_init_se_cmd() does not initialize all fields, so do it
+	 * here.
+	 */
+	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
+	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
+	ioctx->cmd.map_tag = tag;
+	ioctx->cmd.map_cpu = cpu;
+
+	return ioctx;
+}
+
+/**
+ * srpt_abort_cmd - abort a SCSI command
+ * @ioctx:   I/O context associated with the SCSI command.
+ */
+static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
+{
+	enum srpt_command_state state;
+
+	BUG_ON(!ioctx);
+
+	/*
+	 * If the command is in a state where the target core is waiting for
+	 * the ib_srpt driver, change the state to the next state.
+	 */
+
+	state = ioctx->state;
+	switch (state) {
+	case SRPT_STATE_NEED_DATA:
+		ioctx->state = SRPT_STATE_DATA_IN;
+		break;
+	case SRPT_STATE_CMD_RSP_SENT:
+	case SRPT_STATE_MGMT_RSP_SENT:
+		ioctx->state = SRPT_STATE_DONE;
+		break;
+	default:
+		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
+			  __func__, state);
+		break;
+	}
+
+	pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
+		 ioctx->state, ioctx->cmd.tag);
+
+	switch (state) {
+	case SRPT_STATE_NEW:
+	case SRPT_STATE_DATA_IN:
+	case SRPT_STATE_MGMT:
+	case SRPT_STATE_DONE:
+		/*
+		 * Do nothing - defer abort processing until
+		 * srpt_queue_response() is invoked.
+		 */
+		break;
+	case SRPT_STATE_NEED_DATA:
+		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
+		transport_generic_request_failure(&ioctx->cmd,
+					TCM_CHECK_CONDITION_ABORT_CMD);
+		break;
+	case SRPT_STATE_CMD_RSP_SENT:
+		/*
+		 * SRP_RSP sending failed or the SRP_RSP send completion has
+		 * not been received in time.
+		 */
+		transport_generic_free_cmd(&ioctx->cmd, 0);
+		break;
+	case SRPT_STATE_MGMT_RSP_SENT:
+		transport_generic_free_cmd(&ioctx->cmd, 0);
+		break;
+	default:
+		WARN(1, "Unexpected command state (%d)", state);
+		break;
+	}
+
+	return state;
+}
+
+/**
+ * srpt_rdma_read_done - RDMA read completion callback
+ * @cq: Completion queue.
+ * @wc: Work completion.
+ *
+ * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
+ * the data that has been transferred via IB RDMA had to be postponed until the
+ * check_stop_free() callback.  None of this is necessary anymore and needs to
+ * be cleaned up.
+ */
+static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct srpt_rdma_ch *ch = wc->qp->qp_context;
+	struct srpt_send_ioctx *ioctx =
+		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
+
+	WARN_ON(ioctx->n_rdma <= 0);
+	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
+	ioctx->n_rdma = 0;
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
+			ioctx, wc->status);
+		srpt_abort_cmd(ioctx);
+		return;
+	}
+
+	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
+					SRPT_STATE_DATA_IN))
+		target_execute_cmd(&ioctx->cmd);
+	else
+		pr_err("%s[%d]: wrong state = %d\n", __func__,
+		       __LINE__, ioctx->state);
+}
+
+/**
+ * srpt_build_cmd_rsp - build a SRP_RSP response
+ * @ch: RDMA channel through which the request has been received.
+ * @ioctx: I/O context associated with the SRP_CMD request. The response will
+ *   be built in the buffer ioctx->buf points at and hence this function will
+ *   overwrite the request data.
+ * @tag: tag of the request for which this response is being generated.
+ * @status: value for the STATUS field of the SRP_RSP information unit.
+ *
+ * Returns the size in bytes of the SRP_RSP response.
+ *
+ * An SRP_RSP response contains a SCSI status or service response. See also
+ * section 6.9 in the SRP r16a document for the format of an SRP_RSP
+ * response. See also SPC-2 for more information about sense data.
+ */
+static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
+			      struct srpt_send_ioctx *ioctx, u64 tag,
+			      int status)
+{
+	struct se_cmd *cmd = &ioctx->cmd;
+	struct srp_rsp *srp_rsp;
+	const u8 *sense_data;
+	int sense_data_len, max_sense_len;
+	u32 resid = cmd->residual_count;
+
+	/*
+	 * The lowest bit of all SAM-3 status codes is zero (see also
+	 * paragraph 5.3 in SAM-3).
+	 */
+	WARN_ON(status & 1);
+
+	srp_rsp = ioctx->ioctx.buf;
+	BUG_ON(!srp_rsp);
+
+	sense_data = ioctx->sense_data;
+	sense_data_len = ioctx->cmd.scsi_sense_length;
+	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
+
+	memset(srp_rsp, 0, sizeof(*srp_rsp));
+	srp_rsp->opcode = SRP_RSP;
+	srp_rsp->req_lim_delta =
+		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
+	srp_rsp->tag = tag;
+	srp_rsp->status = status;
+
+	if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
+		if (cmd->data_direction == DMA_TO_DEVICE) {
+			/* residual data from an underflow write */
+			srp_rsp->flags = SRP_RSP_FLAG_DOUNDER;
+			srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
+		} else if (cmd->data_direction == DMA_FROM_DEVICE) {
+			/* residual data from an underflow read */
+			srp_rsp->flags = SRP_RSP_FLAG_DIUNDER;
+			srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
+		}
+	} else if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
+		if (cmd->data_direction == DMA_TO_DEVICE) {
+			/* residual data from an overflow write */
+			srp_rsp->flags = SRP_RSP_FLAG_DOOVER;
+			srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
+		} else if (cmd->data_direction == DMA_FROM_DEVICE) {
+			/* residual data from an overflow read */
+			srp_rsp->flags = SRP_RSP_FLAG_DIOVER;
+			srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
+		}
+	}
+
+	if (sense_data_len) {
+		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
+		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
+		if (sense_data_len > max_sense_len) {
+			pr_warn("truncated sense data from %d to %d bytes\n",
+				sense_data_len, max_sense_len);
+			sense_data_len = max_sense_len;
+		}
+
+		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
+		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
+		memcpy(srp_rsp->data, sense_data, sense_data_len);
+	}
+
+	return sizeof(*srp_rsp) + sense_data_len;
+}
+
+/**
+ * srpt_build_tskmgmt_rsp - build a task management response
+ * @ch:       RDMA channel through which the request has been received.
+ * @ioctx:    I/O context in which the SRP_RSP response will be built.
+ * @rsp_code: RSP_CODE that will be stored in the response.
+ * @tag:      Tag of the request for which this response is being generated.
+ *
+ * Returns the size in bytes of the SRP_RSP response.
+ *
+ * An SRP_RSP response contains a SCSI status or service response. See also
+ * section 6.9 in the SRP r16a document for the format of an SRP_RSP
+ * response.
+ */
+static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
+				  struct srpt_send_ioctx *ioctx,
+				  u8 rsp_code, u64 tag)
+{
+	struct srp_rsp *srp_rsp;
+	int resp_data_len;
+	int resp_len;
+
+	resp_data_len = 4;
+	resp_len = sizeof(*srp_rsp) + resp_data_len;
+
+	srp_rsp = ioctx->ioctx.buf;
+	BUG_ON(!srp_rsp);
+	memset(srp_rsp, 0, sizeof(*srp_rsp));
+
+	srp_rsp->opcode = SRP_RSP;
+	srp_rsp->req_lim_delta =
+		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
+	srp_rsp->tag = tag;
+
+	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
+	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
+	srp_rsp->data[3] = rsp_code;
+
+	return resp_len;
+}
+
+static int srpt_check_stop_free(struct se_cmd *cmd)
+{
+	struct srpt_send_ioctx *ioctx = container_of(cmd,
+				struct srpt_send_ioctx, cmd);
+
+	return target_put_sess_cmd(&ioctx->cmd);
+}
+
+/**
+ * srpt_handle_cmd - process a SRP_CMD information unit
+ * @ch: SRPT RDMA channel.
+ * @recv_ioctx: Receive I/O context.
+ * @send_ioctx: Send I/O context.
+ */
+static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
+			    struct srpt_recv_ioctx *recv_ioctx,
+			    struct srpt_send_ioctx *send_ioctx)
+{
+	struct se_cmd *cmd;
+	struct srp_cmd *srp_cmd;
+	struct scatterlist *sg = NULL;
+	unsigned sg_cnt = 0;
+	u64 data_len;
+	enum dma_data_direction dir;
+	int rc;
+
+	BUG_ON(!send_ioctx);
+
+	srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
+	cmd = &send_ioctx->cmd;
+	cmd->tag = srp_cmd->tag;
+
+	switch (srp_cmd->task_attr) {
+	case SRP_CMD_SIMPLE_Q:
+		cmd->sam_task_attr = TCM_SIMPLE_TAG;
+		break;
+	case SRP_CMD_ORDERED_Q:
+	default:
+		cmd->sam_task_attr = TCM_ORDERED_TAG;
+		break;
+	case SRP_CMD_HEAD_OF_Q:
+		cmd->sam_task_attr = TCM_HEAD_TAG;
+		break;
+	case SRP_CMD_ACA:
+		cmd->sam_task_attr = TCM_ACA_TAG;
+		break;
+	}
+
+	rc = srpt_get_desc_tbl(recv_ioctx, send_ioctx, srp_cmd, &dir,
+			       &sg, &sg_cnt, &data_len, ch->imm_data_offset);
+	if (rc) {
+		if (rc != -EAGAIN) {
+			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
+			       srp_cmd->tag);
+		}
+		goto busy;
+	}
+
+	rc = target_init_cmd(cmd, ch->sess, &send_ioctx->sense_data[0],
+			     scsilun_to_int(&srp_cmd->lun), data_len,
+			     TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF);
+	if (rc != 0) {
+		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
+			 srp_cmd->tag);
+		goto busy;
+	}
+
+	if (target_submit_prep(cmd, srp_cmd->cdb, sg, sg_cnt, NULL, 0, NULL, 0,
+			       GFP_KERNEL))
+		return;
+
+	target_submit(cmd);
+	return;
+
+busy:
+	target_send_busy(cmd);
+}
+
+static int srp_tmr_to_tcm(int fn)
+{
+	switch (fn) {
+	case SRP_TSK_ABORT_TASK:
+		return TMR_ABORT_TASK;
+	case SRP_TSK_ABORT_TASK_SET:
+		return TMR_ABORT_TASK_SET;
+	case SRP_TSK_CLEAR_TASK_SET:
+		return TMR_CLEAR_TASK_SET;
+	case SRP_TSK_LUN_RESET:
+		return TMR_LUN_RESET;
+	case SRP_TSK_CLEAR_ACA:
+		return TMR_CLEAR_ACA;
+	default:
+		return -1;
+	}
+}
+
+/**
+ * srpt_handle_tsk_mgmt - process a SRP_TSK_MGMT information unit
+ * @ch: SRPT RDMA channel.
+ * @recv_ioctx: Receive I/O context.
+ * @send_ioctx: Send I/O context.
+ *
+ * Returns 0 if and only if the request will be processed by the target core.
+ *
+ * For more information about SRP_TSK_MGMT information units, see also section
+ * 6.7 in the SRP r16a document.
+ */
+static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
+				 struct srpt_recv_ioctx *recv_ioctx,
+				 struct srpt_send_ioctx *send_ioctx)
+{
+	struct srp_tsk_mgmt *srp_tsk;
+	struct se_cmd *cmd;
+	struct se_session *sess = ch->sess;
+	int tcm_tmr;
+	int rc;
+
+	BUG_ON(!send_ioctx);
+
+	srp_tsk = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
+	cmd = &send_ioctx->cmd;
+
+	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld ch %p sess %p\n",
+		 srp_tsk->tsk_mgmt_func, srp_tsk->task_tag, srp_tsk->tag, ch,
+		 ch->sess);
+
+	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
+	send_ioctx->cmd.tag = srp_tsk->tag;
+	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
+	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
+			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
+			       GFP_KERNEL, srp_tsk->task_tag,
+			       TARGET_SCF_ACK_KREF);
+	if (rc != 0) {
+		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
+		cmd->se_tfo->queue_tm_rsp(cmd);
+	}
+	return;
+}
+
+/**
+ * srpt_handle_new_iu - process a newly received information unit
+ * @ch:    RDMA channel through which the information unit has been received.
+ * @recv_ioctx: Receive I/O context associated with the information unit.
+ */
+static bool
+srpt_handle_new_iu(struct srpt_rdma_ch *ch, struct srpt_recv_ioctx *recv_ioctx)
+{
+	struct srpt_send_ioctx *send_ioctx = NULL;
+	struct srp_cmd *srp_cmd;
+	bool res = false;
+	u8 opcode;
+
+	BUG_ON(!ch);
+	BUG_ON(!recv_ioctx);
+
+	if (unlikely(ch->state == CH_CONNECTING))
+		goto push;
+
+	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
+				   recv_ioctx->ioctx.dma,
+				   recv_ioctx->ioctx.offset + srp_max_req_size,
+				   DMA_FROM_DEVICE);
+
+	srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
+	opcode = srp_cmd->opcode;
+	if (opcode == SRP_CMD || opcode == SRP_TSK_MGMT) {
+		send_ioctx = srpt_get_send_ioctx(ch);
+		if (unlikely(!send_ioctx))
+			goto push;
+	}
+
+	if (!list_empty(&recv_ioctx->wait_list)) {
+		WARN_ON_ONCE(!ch->processing_wait_list);
+		list_del_init(&recv_ioctx->wait_list);
+	}
+
+	switch (opcode) {
+	case SRP_CMD:
+		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
+		break;
+	case SRP_TSK_MGMT:
+		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
+		break;
+	case SRP_I_LOGOUT:
+		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
+		break;
+	case SRP_CRED_RSP:
+		pr_debug("received SRP_CRED_RSP\n");
+		break;
+	case SRP_AER_RSP:
+		pr_debug("received SRP_AER_RSP\n");
+		break;
+	case SRP_RSP:
+		pr_err("Received SRP_RSP\n");
+		break;
+	default:
+		pr_err("received IU with unknown opcode 0x%x\n", opcode);
+		break;
+	}
+
+	if (!send_ioctx || !send_ioctx->recv_ioctx)
+		srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
+	res = true;
+
+out:
+	return res;
+
+push:
+	if (list_empty(&recv_ioctx->wait_list)) {
+		WARN_ON_ONCE(ch->processing_wait_list);
+		list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
+	}
+	goto out;
+}
+
+static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct srpt_rdma_ch *ch = wc->qp->qp_context;
+	struct srpt_recv_ioctx *ioctx =
+		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
+
+	if (wc->status == IB_WC_SUCCESS) {
+		int req_lim;
+
+		req_lim = atomic_dec_return(&ch->req_lim);
+		if (unlikely(req_lim < 0))
+			pr_err("req_lim = %d < 0\n", req_lim);
+		ioctx->byte_len = wc->byte_len;
+		srpt_handle_new_iu(ch, ioctx);
+	} else {
+		pr_info_ratelimited("receiving failed for ioctx %p with status %d\n",
+				    ioctx, wc->status);
+	}
+}
+
+/*
+ * This function must be called from the context in which RDMA completions are
+ * processed because it accesses the wait list without protection against
+ * access from other threads.
+ */
+static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
+{
+	struct srpt_recv_ioctx *recv_ioctx, *tmp;
+
+	WARN_ON_ONCE(ch->state == CH_CONNECTING);
+
+	if (list_empty(&ch->cmd_wait_list))
+		return;
+
+	WARN_ON_ONCE(ch->processing_wait_list);
+	ch->processing_wait_list = true;
+	list_for_each_entry_safe(recv_ioctx, tmp, &ch->cmd_wait_list,
+				 wait_list) {
+		if (!srpt_handle_new_iu(ch, recv_ioctx))
+			break;
+	}
+	ch->processing_wait_list = false;
+}
+
+/**
+ * srpt_send_done - send completion callback
+ * @cq: Completion queue.
+ * @wc: Work completion.
+ *
+ * Note: Although this has not yet been observed during tests, at least in
+ * theory it is possible that the srpt_get_send_ioctx() call invoked by
+ * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
+ * value in each response is set to one, and it is possible that this response
+ * makes the initiator send a new request before the send completion for that
+ * response has been processed. This could e.g. happen if the call to
+ * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
+ * if IB retransmission causes generation of the send completion to be
+ * delayed. Incoming information units for which srpt_get_send_ioctx() fails
+ * are queued on cmd_wait_list. The code below processes these delayed
+ * requests one at a time.
+ */
+static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct srpt_rdma_ch *ch = wc->qp->qp_context;
+	struct srpt_send_ioctx *ioctx =
+		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
+	enum srpt_command_state state;
+
+	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
+
+	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
+		state != SRPT_STATE_MGMT_RSP_SENT);
+
+	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
+
+	if (wc->status != IB_WC_SUCCESS)
+		pr_info("sending response for ioctx 0x%p failed with status %d\n",
+			ioctx, wc->status);
+
+	if (state != SRPT_STATE_DONE) {
+		transport_generic_free_cmd(&ioctx->cmd, 0);
+	} else {
+		pr_err("IB completion has been received too late for wr_id = %u.\n",
+		       ioctx->ioctx.index);
+	}
+
+	srpt_process_wait_list(ch);
+}
+
+/**
+ * srpt_create_ch_ib - create receive and send completion queues
+ * @ch: SRPT RDMA channel.
+ */
+static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
+{
+	struct ib_qp_init_attr *qp_init;
+	struct srpt_port *sport = ch->sport;
+	struct srpt_device *sdev = sport->sdev;
+	const struct ib_device_attr *attrs = &sdev->device->attrs;
+	int sq_size = sport->port_attrib.srp_sq_size;
+	int i, ret;
+
+	WARN_ON(ch->rq_size < 1);
+
+	ret = -ENOMEM;
+	qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
+	if (!qp_init)
+		goto out;
+
+retry:
+	ch->cq = ib_cq_pool_get(sdev->device, ch->rq_size + sq_size, -1,
+				 IB_POLL_WORKQUEUE);
+	if (IS_ERR(ch->cq)) {
+		ret = PTR_ERR(ch->cq);
+		pr_err("failed to create CQ cqe= %d ret= %d\n",
+		       ch->rq_size + sq_size, ret);
+		goto out;
+	}
+	ch->cq_size = ch->rq_size + sq_size;
+
+	qp_init->qp_context = (void *)ch;
+	qp_init->event_handler
+		= (void(*)(struct ib_event *, void*))srpt_qp_event;
+	qp_init->send_cq = ch->cq;
+	qp_init->recv_cq = ch->cq;
+	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
+	qp_init->qp_type = IB_QPT_RC;
+	/*
+	 * We divide up our send queue size into half SEND WRs to send the
+	 * completions, and half R/W contexts to actually do the RDMA
+	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
+	 * both both, as RDMA contexts will also post completions for the
+	 * RDMA READ case.
+	 */
+	qp_init->cap.max_send_wr = min(sq_size / 2, attrs->max_qp_wr);
+	qp_init->cap.max_rdma_ctxs = sq_size / 2;
+	qp_init->cap.max_send_sge = attrs->max_send_sge;
+	qp_init->cap.max_recv_sge = 1;
+	qp_init->port_num = ch->sport->port;
+	if (sdev->use_srq)
+		qp_init->srq = sdev->srq;
+	else
+		qp_init->cap.max_recv_wr = ch->rq_size;
+
+	if (ch->using_rdma_cm) {
+		ret = rdma_create_qp(ch->rdma_cm.cm_id, sdev->pd, qp_init);
+		ch->qp = ch->rdma_cm.cm_id->qp;
+	} else {
+		ch->qp = ib_create_qp(sdev->pd, qp_init);
+		if (!IS_ERR(ch->qp)) {
+			ret = srpt_init_ch_qp(ch, ch->qp);
+			if (ret)
+				ib_destroy_qp(ch->qp);
+		} else {
+			ret = PTR_ERR(ch->qp);
+		}
+	}
+	if (ret) {
+		bool retry = sq_size > MIN_SRPT_SQ_SIZE;
+
+		if (retry) {
+			pr_debug("failed to create queue pair with sq_size = %d (%d) - retrying\n",
+				 sq_size, ret);
+			ib_cq_pool_put(ch->cq, ch->cq_size);
+			sq_size = max(sq_size / 2, MIN_SRPT_SQ_SIZE);
+			goto retry;
+		} else {
+			pr_err("failed to create queue pair with sq_size = %d (%d)\n",
+			       sq_size, ret);
+			goto err_destroy_cq;
+		}
+	}
+
+	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
+
+	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d ch= %p\n",
+		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
+		 qp_init->cap.max_send_wr, ch);
+
+	if (!sdev->use_srq)
+		for (i = 0; i < ch->rq_size; i++)
+			srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
+
+out:
+	kfree(qp_init);
+	return ret;
+
+err_destroy_cq:
+	ch->qp = NULL;
+	ib_cq_pool_put(ch->cq, ch->cq_size);
+	goto out;
+}
+
+static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
+{
+	ib_destroy_qp(ch->qp);
+	ib_cq_pool_put(ch->cq, ch->cq_size);
+}
+
+/**
+ * srpt_close_ch - close a RDMA channel
+ * @ch: SRPT RDMA channel.
+ *
+ * Make sure all resources associated with the channel will be deallocated at
+ * an appropriate time.
+ *
+ * Returns true if and only if the channel state has been modified into
+ * CH_DRAINING.
+ */
+static bool srpt_close_ch(struct srpt_rdma_ch *ch)
+{
+	int ret;
+
+	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
+		pr_debug("%s: already closed\n", ch->sess_name);
+		return false;
+	}
+
+	kref_get(&ch->kref);
+
+	ret = srpt_ch_qp_err(ch);
+	if (ret < 0)
+		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
+		       ch->sess_name, ch->qp->qp_num, ret);
+
+	ret = srpt_zerolength_write(ch);
+	if (ret < 0) {
+		pr_err("%s-%d: queuing zero-length write failed: %d\n",
+		       ch->sess_name, ch->qp->qp_num, ret);
+		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
+			schedule_work(&ch->release_work);
+		else
+			WARN_ON_ONCE(true);
+	}
+
+	kref_put(&ch->kref, srpt_free_ch);
+
+	return true;
+}
+
+/*
+ * Change the channel state into CH_DISCONNECTING. If a channel has not yet
+ * reached the connected state, close it. If a channel is in the connected
+ * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
+ * the responsibility of the caller to ensure that this function is not
+ * invoked concurrently with the code that accepts a connection. This means
+ * that this function must either be invoked from inside a CM callback
+ * function or that it must be invoked with the srpt_port.mutex held.
+ */
+static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
+{
+	int ret;
+
+	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
+		return -ENOTCONN;
+
+	if (ch->using_rdma_cm) {
+		ret = rdma_disconnect(ch->rdma_cm.cm_id);
+	} else {
+		ret = ib_send_cm_dreq(ch->ib_cm.cm_id, NULL, 0);
+		if (ret < 0)
+			ret = ib_send_cm_drep(ch->ib_cm.cm_id, NULL, 0);
+	}
+
+	if (ret < 0 && srpt_close_ch(ch))
+		ret = 0;
+
+	return ret;
+}
+
+/* Send DREQ and wait for DREP. */
+static void srpt_disconnect_ch_sync(struct srpt_rdma_ch *ch)
+{
+	DECLARE_COMPLETION_ONSTACK(closed);
+	struct srpt_port *sport = ch->sport;
+
+	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
+		 ch->state);
+
+	ch->closed = &closed;
+
+	mutex_lock(&sport->mutex);
+	srpt_disconnect_ch(ch);
+	mutex_unlock(&sport->mutex);
+
+	while (wait_for_completion_timeout(&closed, 5 * HZ) == 0)
+		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
+			ch->sess_name, ch->qp->qp_num, ch->state);
+
+}
+
+static void __srpt_close_all_ch(struct srpt_port *sport)
+{
+	struct srpt_nexus *nexus;
+	struct srpt_rdma_ch *ch;
+
+	lockdep_assert_held(&sport->mutex);
+
+	list_for_each_entry(nexus, &sport->nexus_list, entry) {
+		list_for_each_entry(ch, &nexus->ch_list, list) {
+			if (srpt_disconnect_ch(ch) >= 0)
+				pr_info("Closing channel %s-%d because target %s_%d has been disabled\n",
+					ch->sess_name, ch->qp->qp_num,
+					dev_name(&sport->sdev->device->dev),
+					sport->port);
+			srpt_close_ch(ch);
+		}
+	}
+}
+
+/*
+ * Look up (i_port_id, t_port_id) in sport->nexus_list. Create an entry if
+ * it does not yet exist.
+ */
+static struct srpt_nexus *srpt_get_nexus(struct srpt_port *sport,
+					 const u8 i_port_id[16],
+					 const u8 t_port_id[16])
+{
+	struct srpt_nexus *nexus = NULL, *tmp_nexus = NULL, *n;
+
+	for (;;) {
+		mutex_lock(&sport->mutex);
+		list_for_each_entry(n, &sport->nexus_list, entry) {
+			if (memcmp(n->i_port_id, i_port_id, 16) == 0 &&
+			    memcmp(n->t_port_id, t_port_id, 16) == 0) {
+				nexus = n;
+				break;
+			}
+		}
+		if (!nexus && tmp_nexus) {
+			list_add_tail_rcu(&tmp_nexus->entry,
+					  &sport->nexus_list);
+			swap(nexus, tmp_nexus);
+		}
+		mutex_unlock(&sport->mutex);
+
+		if (nexus)
+			break;
+		tmp_nexus = kzalloc(sizeof(*nexus), GFP_KERNEL);
+		if (!tmp_nexus) {
+			nexus = ERR_PTR(-ENOMEM);
+			break;
+		}
+		INIT_LIST_HEAD(&tmp_nexus->ch_list);
+		memcpy(tmp_nexus->i_port_id, i_port_id, 16);
+		memcpy(tmp_nexus->t_port_id, t_port_id, 16);
+	}
+
+	kfree(tmp_nexus);
+
+	return nexus;
+}
+
+static void srpt_set_enabled(struct srpt_port *sport, bool enabled)
+	__must_hold(&sport->mutex)
+{
+	lockdep_assert_held(&sport->mutex);
+
+	if (sport->enabled == enabled)
+		return;
+	sport->enabled = enabled;
+	if (!enabled)
+		__srpt_close_all_ch(sport);
+}
+
+static void srpt_drop_sport_ref(struct srpt_port *sport)
+{
+	if (atomic_dec_return(&sport->refcount) == 0 && sport->freed_channels)
+		complete(sport->freed_channels);
+}
+
+static void srpt_free_ch(struct kref *kref)
+{
+	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
+
+	srpt_drop_sport_ref(ch->sport);
+	kfree_rcu(ch, rcu);
+}
+
+/*
+ * Shut down the SCSI target session, tell the connection manager to
+ * disconnect the associated RDMA channel, transition the QP to the error
+ * state and remove the channel from the channel list. This function is
+ * typically called from inside srpt_zerolength_write_done(). Concurrent
+ * srpt_zerolength_write() calls from inside srpt_close_ch() are possible
+ * as long as the channel is on sport->nexus_list.
+ */
+static void srpt_release_channel_work(struct work_struct *w)
+{
+	struct srpt_rdma_ch *ch;
+	struct srpt_device *sdev;
+	struct srpt_port *sport;
+	struct se_session *se_sess;
+
+	ch = container_of(w, struct srpt_rdma_ch, release_work);
+	pr_debug("%s-%d\n", ch->sess_name, ch->qp->qp_num);
+
+	sdev = ch->sport->sdev;
+	BUG_ON(!sdev);
+
+	se_sess = ch->sess;
+	BUG_ON(!se_sess);
+
+	target_stop_session(se_sess);
+	target_wait_for_sess_cmds(se_sess);
+
+	target_remove_session(se_sess);
+	ch->sess = NULL;
+
+	if (ch->using_rdma_cm)
+		rdma_destroy_id(ch->rdma_cm.cm_id);
+	else
+		ib_destroy_cm_id(ch->ib_cm.cm_id);
+
+	sport = ch->sport;
+	mutex_lock(&sport->mutex);
+	list_del_rcu(&ch->list);
+	mutex_unlock(&sport->mutex);
+
+	if (ch->closed)
+		complete(ch->closed);
+
+	srpt_destroy_ch_ib(ch);
+
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     ch->rsp_buf_cache, DMA_TO_DEVICE);
+
+	kmem_cache_destroy(ch->rsp_buf_cache);
+
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
+			     sdev, ch->rq_size,
+			     ch->req_buf_cache, DMA_FROM_DEVICE);
+
+	kmem_cache_destroy(ch->req_buf_cache);
+
+	kref_put(&ch->kref, srpt_free_ch);
+}
+
+/**
+ * srpt_cm_req_recv - process the event IB_CM_REQ_RECEIVED
+ * @sdev: HCA through which the login request was received.
+ * @ib_cm_id: IB/CM connection identifier in case of IB/CM.
+ * @rdma_cm_id: RDMA/CM connection identifier in case of RDMA/CM.
+ * @port_num: Port through which the REQ message was received.
+ * @pkey: P_Key of the incoming connection.
+ * @req: SRP login request.
+ * @src_addr: GID (IB/CM) or IP address (RDMA/CM) of the port that submitted
+ * the login request.
+ *
+ * Ownership of the cm_id is transferred to the target session if this
+ * function returns zero. Otherwise the caller remains the owner of cm_id.
+ */
+static int srpt_cm_req_recv(struct srpt_device *const sdev,
+			    struct ib_cm_id *ib_cm_id,
+			    struct rdma_cm_id *rdma_cm_id,
+			    u8 port_num, __be16 pkey,
+			    const struct srp_login_req *req,
+			    const char *src_addr)
+{
+	struct srpt_port *sport = &sdev->port[port_num - 1];
+	struct srpt_nexus *nexus;
+	struct srp_login_rsp *rsp = NULL;
+	struct srp_login_rej *rej = NULL;
+	union {
+		struct rdma_conn_param rdma_cm;
+		struct ib_cm_rep_param ib_cm;
+	} *rep_param = NULL;
+	struct srpt_rdma_ch *ch = NULL;
+	char i_port_id[36];
+	u32 it_iu_len;
+	int i, tag_num, tag_size, ret;
+	struct srpt_tpg *stpg;
+
+	WARN_ON_ONCE(irqs_disabled());
+
+	it_iu_len = be32_to_cpu(req->req_it_iu_len);
+
+	pr_info("Received SRP_LOGIN_REQ with i_port_id %pI6, t_port_id %pI6 and it_iu_len %d on port %d (guid=%pI6); pkey %#04x\n",
+		req->initiator_port_id, req->target_port_id, it_iu_len,
+		port_num, &sport->gid, be16_to_cpu(pkey));
+
+	nexus = srpt_get_nexus(sport, req->initiator_port_id,
+			       req->target_port_id);
+	if (IS_ERR(nexus)) {
+		ret = PTR_ERR(nexus);
+		goto out;
+	}
+
+	ret = -ENOMEM;
+	rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
+	rej = kzalloc(sizeof(*rej), GFP_KERNEL);
+	rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
+	if (!rsp || !rej || !rep_param)
+		goto out;
+
+	ret = -EINVAL;
+	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
+		rej->reason = cpu_to_be32(
+				SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
+		pr_err("rejected SRP_LOGIN_REQ because its length (%d bytes) is out of range (%d .. %d)\n",
+		       it_iu_len, 64, srp_max_req_size);
+		goto reject;
+	}
+
+	if (!sport->enabled) {
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_info("rejected SRP_LOGIN_REQ because target port %s_%d has not yet been enabled\n",
+			dev_name(&sport->sdev->device->dev), port_num);
+		goto reject;
+	}
+
+	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
+	    || *(__be64 *)(req->target_port_id + 8) !=
+	       cpu_to_be64(srpt_service_guid)) {
+		rej->reason = cpu_to_be32(
+				SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
+		pr_err("rejected SRP_LOGIN_REQ because it has an invalid target port identifier.\n");
+		goto reject;
+	}
+
+	ret = -ENOMEM;
+	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
+	if (!ch) {
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_err("rejected SRP_LOGIN_REQ because out of memory.\n");
+		goto reject;
+	}
+
+	kref_init(&ch->kref);
+	ch->pkey = be16_to_cpu(pkey);
+	ch->nexus = nexus;
+	ch->zw_cqe.done = srpt_zerolength_write_done;
+	INIT_WORK(&ch->release_work, srpt_release_channel_work);
+	ch->sport = sport;
+	if (rdma_cm_id) {
+		ch->using_rdma_cm = true;
+		ch->rdma_cm.cm_id = rdma_cm_id;
+		rdma_cm_id->context = ch;
+	} else {
+		ch->ib_cm.cm_id = ib_cm_id;
+		ib_cm_id->context = ch;
+	}
+	/*
+	 * ch->rq_size should be at least as large as the initiator queue
+	 * depth to avoid that the initiator driver has to report QUEUE_FULL
+	 * to the SCSI mid-layer.
+	 */
+	ch->rq_size = min(MAX_SRPT_RQ_SIZE, sdev->device->attrs.max_qp_wr);
+	spin_lock_init(&ch->spinlock);
+	ch->state = CH_CONNECTING;
+	INIT_LIST_HEAD(&ch->cmd_wait_list);
+	ch->max_rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
+
+	ch->rsp_buf_cache = kmem_cache_create("srpt-rsp-buf", ch->max_rsp_size,
+					      512, 0, NULL);
+	if (!ch->rsp_buf_cache)
+		goto free_ch;
+
+	ch->ioctx_ring = (struct srpt_send_ioctx **)
+		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
+				      sizeof(*ch->ioctx_ring[0]),
+				      ch->rsp_buf_cache, 0, DMA_TO_DEVICE);
+	if (!ch->ioctx_ring) {
+		pr_err("rejected SRP_LOGIN_REQ because creating a new QP SQ ring failed.\n");
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		goto free_rsp_cache;
+	}
+
+	for (i = 0; i < ch->rq_size; i++)
+		ch->ioctx_ring[i]->ch = ch;
+	if (!sdev->use_srq) {
+		u16 imm_data_offset = req->req_flags & SRP_IMMED_REQUESTED ?
+			be16_to_cpu(req->imm_data_offset) : 0;
+		u16 alignment_offset;
+		u32 req_sz;
+
+		if (req->req_flags & SRP_IMMED_REQUESTED)
+			pr_debug("imm_data_offset = %d\n",
+				 be16_to_cpu(req->imm_data_offset));
+		if (imm_data_offset >= sizeof(struct srp_cmd)) {
+			ch->imm_data_offset = imm_data_offset;
+			rsp->rsp_flags |= SRP_LOGIN_RSP_IMMED_SUPP;
+		} else {
+			ch->imm_data_offset = 0;
+		}
+		alignment_offset = round_up(imm_data_offset, 512) -
+			imm_data_offset;
+		req_sz = alignment_offset + imm_data_offset + srp_max_req_size;
+		ch->req_buf_cache = kmem_cache_create("srpt-req-buf", req_sz,
+						      512, 0, NULL);
+		if (!ch->req_buf_cache)
+			goto free_rsp_ring;
+
+		ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
+			srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
+					      sizeof(*ch->ioctx_recv_ring[0]),
+					      ch->req_buf_cache,
+					      alignment_offset,
+					      DMA_FROM_DEVICE);
+		if (!ch->ioctx_recv_ring) {
+			pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
+			rej->reason =
+			    cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+			goto free_recv_cache;
+		}
+		for (i = 0; i < ch->rq_size; i++)
+			INIT_LIST_HEAD(&ch->ioctx_recv_ring[i]->wait_list);
+	}
+
+	ret = srpt_create_ch_ib(ch);
+	if (ret) {
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_err("rejected SRP_LOGIN_REQ because creating a new RDMA channel failed.\n");
+		goto free_recv_ring;
+	}
+
+	strscpy(ch->sess_name, src_addr, sizeof(ch->sess_name));
+	snprintf(i_port_id, sizeof(i_port_id), "0x%016llx%016llx",
+			be64_to_cpu(*(__be64 *)nexus->i_port_id),
+			be64_to_cpu(*(__be64 *)(nexus->i_port_id + 8)));
+
+	pr_debug("registering src addr %s or i_port_id %s\n", ch->sess_name,
+		 i_port_id);
+
+	tag_num = ch->rq_size;
+	tag_size = 1; /* ib_srpt does not use se_sess->sess_cmd_map */
+
+	if (sport->guid_id) {
+		mutex_lock(&sport->guid_id->mutex);
+		list_for_each_entry(stpg, &sport->guid_id->tpg_list, entry) {
+			if (!IS_ERR_OR_NULL(ch->sess))
+				break;
+			ch->sess = target_setup_session(&stpg->tpg, tag_num,
+						tag_size, TARGET_PROT_NORMAL,
+						ch->sess_name, ch, NULL);
+		}
+		mutex_unlock(&sport->guid_id->mutex);
+	}
+
+	if (sport->gid_id) {
+		mutex_lock(&sport->gid_id->mutex);
+		list_for_each_entry(stpg, &sport->gid_id->tpg_list, entry) {
+			if (!IS_ERR_OR_NULL(ch->sess))
+				break;
+			ch->sess = target_setup_session(&stpg->tpg, tag_num,
+					tag_size, TARGET_PROT_NORMAL, i_port_id,
+					ch, NULL);
+			if (!IS_ERR_OR_NULL(ch->sess))
+				break;
+			/* Retry without leading "0x" */
+			ch->sess = target_setup_session(&stpg->tpg, tag_num,
+						tag_size, TARGET_PROT_NORMAL,
+						i_port_id + 2, ch, NULL);
+		}
+		mutex_unlock(&sport->gid_id->mutex);
+	}
+
+	if (IS_ERR_OR_NULL(ch->sess)) {
+		WARN_ON_ONCE(ch->sess == NULL);
+		ret = PTR_ERR(ch->sess);
+		ch->sess = NULL;
+		pr_info("Rejected login for initiator %s: ret = %d.\n",
+			ch->sess_name, ret);
+		rej->reason = cpu_to_be32(ret == -ENOMEM ?
+				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
+				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
+		goto destroy_ib;
+	}
+
+	/*
+	 * Once a session has been created destruction of srpt_rdma_ch objects
+	 * will decrement sport->refcount. Hence increment sport->refcount now.
+	 */
+	atomic_inc(&sport->refcount);
+
+	mutex_lock(&sport->mutex);
+
+	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
+		struct srpt_rdma_ch *ch2;
+
+		list_for_each_entry(ch2, &nexus->ch_list, list) {
+			if (srpt_disconnect_ch(ch2) < 0)
+				continue;
+			pr_info("Relogin - closed existing channel %s\n",
+				ch2->sess_name);
+			rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
+		}
+	} else {
+		rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
+	}
+
+	list_add_tail_rcu(&ch->list, &nexus->ch_list);
+
+	if (!sport->enabled) {
+		rej->reason = cpu_to_be32(
+				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_info("rejected SRP_LOGIN_REQ because target %s_%d is not enabled\n",
+			dev_name(&sdev->device->dev), port_num);
+		mutex_unlock(&sport->mutex);
+		ret = -EINVAL;
+		goto reject;
+	}
+
+	mutex_unlock(&sport->mutex);
+
+	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rtr(ch, ch->qp);
+	if (ret) {
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_err("rejected SRP_LOGIN_REQ because enabling RTR failed (error code = %d)\n",
+		       ret);
+		goto reject;
+	}
+
+	pr_debug("Establish connection sess=%p name=%s ch=%p\n", ch->sess,
+		 ch->sess_name, ch);
+
+	/* create srp_login_response */
+	rsp->opcode = SRP_LOGIN_RSP;
+	rsp->tag = req->tag;
+	rsp->max_it_iu_len = cpu_to_be32(srp_max_req_size);
+	rsp->max_ti_iu_len = req->req_it_iu_len;
+	ch->max_ti_iu_len = it_iu_len;
+	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
+				   SRP_BUF_FORMAT_INDIRECT);
+	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
+	atomic_set(&ch->req_lim, ch->rq_size);
+	atomic_set(&ch->req_lim_delta, 0);
+
+	/* create cm reply */
+	if (ch->using_rdma_cm) {
+		rep_param->rdma_cm.private_data = (void *)rsp;
+		rep_param->rdma_cm.private_data_len = sizeof(*rsp);
+		rep_param->rdma_cm.rnr_retry_count = 7;
+		rep_param->rdma_cm.flow_control = 1;
+		rep_param->rdma_cm.responder_resources = 4;
+		rep_param->rdma_cm.initiator_depth = 4;
+	} else {
+		rep_param->ib_cm.qp_num = ch->qp->qp_num;
+		rep_param->ib_cm.private_data = (void *)rsp;
+		rep_param->ib_cm.private_data_len = sizeof(*rsp);
+		rep_param->ib_cm.rnr_retry_count = 7;
+		rep_param->ib_cm.flow_control = 1;
+		rep_param->ib_cm.failover_accepted = 0;
+		rep_param->ib_cm.srq = 1;
+		rep_param->ib_cm.responder_resources = 4;
+		rep_param->ib_cm.initiator_depth = 4;
+	}
+
+	/*
+	 * Hold the sport mutex while accepting a connection to avoid that
+	 * srpt_disconnect_ch() is invoked concurrently with this code.
+	 */
+	mutex_lock(&sport->mutex);
+	if (sport->enabled && ch->state == CH_CONNECTING) {
+		if (ch->using_rdma_cm)
+			ret = rdma_accept(rdma_cm_id, &rep_param->rdma_cm);
+		else
+			ret = ib_send_cm_rep(ib_cm_id, &rep_param->ib_cm);
+	} else {
+		ret = -EINVAL;
+	}
+	mutex_unlock(&sport->mutex);
+
+	switch (ret) {
+	case 0:
+		break;
+	case -EINVAL:
+		goto reject;
+	default:
+		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_err("sending SRP_LOGIN_REQ response failed (error code = %d)\n",
+		       ret);
+		goto reject;
+	}
+
+	goto out;
+
+destroy_ib:
+	srpt_destroy_ch_ib(ch);
+
+free_recv_ring:
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     ch->req_buf_cache, DMA_FROM_DEVICE);
+
+free_recv_cache:
+	kmem_cache_destroy(ch->req_buf_cache);
+
+free_rsp_ring:
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     ch->rsp_buf_cache, DMA_TO_DEVICE);
+
+free_rsp_cache:
+	kmem_cache_destroy(ch->rsp_buf_cache);
+
+free_ch:
+	if (rdma_cm_id)
+		rdma_cm_id->context = NULL;
+	else
+		ib_cm_id->context = NULL;
+	kfree(ch);
+	ch = NULL;
+
+	WARN_ON_ONCE(ret == 0);
+
+reject:
+	pr_info("Rejecting login with reason %#x\n", be32_to_cpu(rej->reason));
+	rej->opcode = SRP_LOGIN_REJ;
+	rej->tag = req->tag;
+	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
+				   SRP_BUF_FORMAT_INDIRECT);
+
+	if (rdma_cm_id)
+		rdma_reject(rdma_cm_id, rej, sizeof(*rej),
+			    IB_CM_REJ_CONSUMER_DEFINED);
+	else
+		ib_send_cm_rej(ib_cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
+			       rej, sizeof(*rej));
+
+	if (ch && ch->sess) {
+		srpt_close_ch(ch);
+		/*
+		 * Tell the caller not to free cm_id since
+		 * srpt_release_channel_work() will do that.
+		 */
+		ret = 0;
+	}
+
+out:
+	kfree(rep_param);
+	kfree(rsp);
+	kfree(rej);
+
+	return ret;
+}
+
+static int srpt_ib_cm_req_recv(struct ib_cm_id *cm_id,
+			       const struct ib_cm_req_event_param *param,
+			       void *private_data)
+{
+	char sguid[40];
+
+	srpt_format_guid(sguid, sizeof(sguid),
+			 &param->primary_path->dgid.global.interface_id);
+
+	return srpt_cm_req_recv(cm_id->context, cm_id, NULL, param->port,
+				param->primary_path->pkey,
+				private_data, sguid);
+}
+
+static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
+				 struct rdma_cm_event *event)
+{
+	struct srpt_device *sdev;
+	struct srp_login_req req;
+	const struct srp_login_req_rdma *req_rdma;
+	struct sa_path_rec *path_rec = cm_id->route.path_rec;
+	char src_addr[40];
+
+	sdev = ib_get_client_data(cm_id->device, &srpt_client);
+	if (!sdev)
+		return -ECONNREFUSED;
+
+	if (event->param.conn.private_data_len < sizeof(*req_rdma))
+		return -EINVAL;
+
+	/* Transform srp_login_req_rdma into srp_login_req. */
+	req_rdma = event->param.conn.private_data;
+	memset(&req, 0, sizeof(req));
+	req.opcode		= req_rdma->opcode;
+	req.tag			= req_rdma->tag;
+	req.req_it_iu_len	= req_rdma->req_it_iu_len;
+	req.req_buf_fmt		= req_rdma->req_buf_fmt;
+	req.req_flags		= req_rdma->req_flags;
+	memcpy(req.initiator_port_id, req_rdma->initiator_port_id, 16);
+	memcpy(req.target_port_id, req_rdma->target_port_id, 16);
+	req.imm_data_offset	= req_rdma->imm_data_offset;
+
+	snprintf(src_addr, sizeof(src_addr), "%pIS",
+		 &cm_id->route.addr.src_addr);
+
+	return srpt_cm_req_recv(sdev, NULL, cm_id, cm_id->port_num,
+				path_rec ? path_rec->pkey : 0, &req, src_addr);
+}
+
+static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
+			     enum ib_cm_rej_reason reason,
+			     const u8 *private_data,
+			     u8 private_data_len)
+{
+	char *priv = NULL;
+	int i;
+
+	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
+						GFP_KERNEL))) {
+		for (i = 0; i < private_data_len; i++)
+			sprintf(priv + 3 * i, " %02x", private_data[i]);
+	}
+	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
+		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
+		"; private data" : "", priv ? priv : " (?)");
+	kfree(priv);
+}
+
+/**
+ * srpt_cm_rtu_recv - process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event
+ * @ch: SRPT RDMA channel.
+ *
+ * An RTU (ready to use) message indicates that the connection has been
+ * established and that the recipient may begin transmitting.
+ */
+static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
+{
+	int ret;
+
+	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rts(ch, ch->qp);
+	if (ret < 0) {
+		pr_err("%s-%d: QP transition to RTS failed\n", ch->sess_name,
+		       ch->qp->qp_num);
+		srpt_close_ch(ch);
+		return;
+	}
+
+	/*
+	 * Note: calling srpt_close_ch() if the transition to the LIVE state
+	 * fails is not necessary since that means that that function has
+	 * already been invoked from another thread.
+	 */
+	if (!srpt_set_ch_state(ch, CH_LIVE)) {
+		pr_err("%s-%d: channel transition to LIVE state failed\n",
+		       ch->sess_name, ch->qp->qp_num);
+		return;
+	}
+
+	/* Trigger wait list processing. */
+	ret = srpt_zerolength_write(ch);
+	WARN_ONCE(ret < 0, "%d\n", ret);
+}
+
+/**
+ * srpt_cm_handler - IB connection manager callback function
+ * @cm_id: IB/CM connection identifier.
+ * @event: IB/CM event.
+ *
+ * A non-zero return value will cause the caller destroy the CM ID.
+ *
+ * Note: srpt_cm_handler() must only return a non-zero value when transferring
+ * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
+ * a non-zero value in any other case will trigger a race with the
+ * ib_destroy_cm_id() call in srpt_release_channel().
+ */
+static int srpt_cm_handler(struct ib_cm_id *cm_id,
+			   const struct ib_cm_event *event)
+{
+	struct srpt_rdma_ch *ch = cm_id->context;
+	int ret;
+
+	ret = 0;
+	switch (event->event) {
+	case IB_CM_REQ_RECEIVED:
+		ret = srpt_ib_cm_req_recv(cm_id, &event->param.req_rcvd,
+					  event->private_data);
+		break;
+	case IB_CM_REJ_RECEIVED:
+		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
+				 event->private_data,
+				 IB_CM_REJ_PRIVATE_DATA_SIZE);
+		break;
+	case IB_CM_RTU_RECEIVED:
+	case IB_CM_USER_ESTABLISHED:
+		srpt_cm_rtu_recv(ch);
+		break;
+	case IB_CM_DREQ_RECEIVED:
+		srpt_disconnect_ch(ch);
+		break;
+	case IB_CM_DREP_RECEIVED:
+		pr_info("Received CM DREP message for ch %s-%d.\n",
+			ch->sess_name, ch->qp->qp_num);
+		srpt_close_ch(ch);
+		break;
+	case IB_CM_TIMEWAIT_EXIT:
+		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
+			ch->sess_name, ch->qp->qp_num);
+		srpt_close_ch(ch);
+		break;
+	case IB_CM_REP_ERROR:
+		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
+			ch->qp->qp_num);
+		break;
+	case IB_CM_DREQ_ERROR:
+		pr_info("Received CM DREQ ERROR event.\n");
+		break;
+	case IB_CM_MRA_RECEIVED:
+		pr_info("Received CM MRA event\n");
+		break;
+	default:
+		pr_err("received unrecognized CM event %d\n", event->event);
+		break;
+	}
+
+	return ret;
+}
+
+static int srpt_rdma_cm_handler(struct rdma_cm_id *cm_id,
+				struct rdma_cm_event *event)
+{
+	struct srpt_rdma_ch *ch = cm_id->context;
+	int ret = 0;
+
+	switch (event->event) {
+	case RDMA_CM_EVENT_CONNECT_REQUEST:
+		ret = srpt_rdma_cm_req_recv(cm_id, event);
+		break;
+	case RDMA_CM_EVENT_REJECTED:
+		srpt_cm_rej_recv(ch, event->status,
+				 event->param.conn.private_data,
+				 event->param.conn.private_data_len);
+		break;
+	case RDMA_CM_EVENT_ESTABLISHED:
+		srpt_cm_rtu_recv(ch);
+		break;
+	case RDMA_CM_EVENT_DISCONNECTED:
+		if (ch->state < CH_DISCONNECTING)
+			srpt_disconnect_ch(ch);
+		else
+			srpt_close_ch(ch);
+		break;
+	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+		srpt_close_ch(ch);
+		break;
+	case RDMA_CM_EVENT_UNREACHABLE:
+		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
+			ch->qp->qp_num);
+		break;
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+		break;
+	default:
+		pr_err("received unrecognized RDMA CM event %d\n",
+		       event->event);
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * srpt_write_pending - Start data transfer from initiator to target (write).
+ */
+static int srpt_write_pending(struct se_cmd *se_cmd)
+{
+	struct srpt_send_ioctx *ioctx =
+		container_of(se_cmd, struct srpt_send_ioctx, cmd);
+	struct srpt_rdma_ch *ch = ioctx->ch;
+	struct ib_send_wr *first_wr = NULL;
+	struct ib_cqe *cqe = &ioctx->rdma_cqe;
+	enum srpt_command_state new_state;
+	int ret, i;
+
+	if (ioctx->recv_ioctx) {
+		srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN);
+		target_execute_cmd(&ioctx->cmd);
+		return 0;
+	}
+
+	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
+	WARN_ON(new_state == SRPT_STATE_DONE);
+
+	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
+		pr_warn("%s: IB send queue full (needed %d)\n",
+				__func__, ioctx->n_rdma);
+		ret = -ENOMEM;
+		goto out_undo;
+	}
+
+	cqe->done = srpt_rdma_read_done;
+	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
+		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
+
+		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
+				cqe, first_wr);
+		cqe = NULL;
+	}
+
+	ret = ib_post_send(ch->qp, first_wr, NULL);
+	if (ret) {
+		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
+			 __func__, ret, ioctx->n_rdma,
+			 atomic_read(&ch->sq_wr_avail));
+		goto out_undo;
+	}
+
+	return 0;
+out_undo:
+	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
+	return ret;
+}
+
+static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
+{
+	switch (tcm_mgmt_status) {
+	case TMR_FUNCTION_COMPLETE:
+		return SRP_TSK_MGMT_SUCCESS;
+	case TMR_FUNCTION_REJECTED:
+		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
+	}
+	return SRP_TSK_MGMT_FAILED;
+}
+
+/**
+ * srpt_queue_response - transmit the response to a SCSI command
+ * @cmd: SCSI target command.
+ *
+ * Callback function called by the TCM core. Must not block since it can be
+ * invoked on the context of the IB completion handler.
+ */
+static void srpt_queue_response(struct se_cmd *cmd)
+{
+	struct srpt_send_ioctx *ioctx =
+		container_of(cmd, struct srpt_send_ioctx, cmd);
+	struct srpt_rdma_ch *ch = ioctx->ch;
+	struct srpt_device *sdev = ch->sport->sdev;
+	struct ib_send_wr send_wr, *first_wr = &send_wr;
+	struct ib_sge sge;
+	enum srpt_command_state state;
+	int resp_len, ret, i;
+	u8 srp_tm_status;
+
+	state = ioctx->state;
+	switch (state) {
+	case SRPT_STATE_NEW:
+	case SRPT_STATE_DATA_IN:
+		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
+		break;
+	case SRPT_STATE_MGMT:
+		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
+		break;
+	default:
+		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
+			ch, ioctx->ioctx.index, ioctx->state);
+		break;
+	}
+
+	if (WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))
+		return;
+
+	/* For read commands, transfer the data to the initiator. */
+	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
+	    ioctx->cmd.data_length &&
+	    !ioctx->queue_status_only) {
+		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
+			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
+
+			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
+					ch->sport->port, NULL, first_wr);
+		}
+	}
+
+	if (state != SRPT_STATE_MGMT)
+		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
+					      cmd->scsi_status);
+	else {
+		srp_tm_status
+			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
+		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
+						 ioctx->cmd.tag);
+	}
+
+	atomic_inc(&ch->req_lim);
+
+	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
+			&ch->sq_wr_avail) < 0)) {
+		pr_warn("%s: IB send queue full (needed %d)\n",
+				__func__, ioctx->n_rdma);
+		goto out;
+	}
+
+	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
+				      DMA_TO_DEVICE);
+
+	sge.addr = ioctx->ioctx.dma;
+	sge.length = resp_len;
+	sge.lkey = sdev->lkey;
+
+	ioctx->ioctx.cqe.done = srpt_send_done;
+	send_wr.next = NULL;
+	send_wr.wr_cqe = &ioctx->ioctx.cqe;
+	send_wr.sg_list = &sge;
+	send_wr.num_sge = 1;
+	send_wr.opcode = IB_WR_SEND;
+	send_wr.send_flags = IB_SEND_SIGNALED;
+
+	ret = ib_post_send(ch->qp, first_wr, NULL);
+	if (ret < 0) {
+		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
+			__func__, ioctx->cmd.tag, ret);
+		goto out;
+	}
+
+	return;
+
+out:
+	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
+	atomic_dec(&ch->req_lim);
+	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
+	target_put_sess_cmd(&ioctx->cmd);
+}
+
+static int srpt_queue_data_in(struct se_cmd *cmd)
+{
+	srpt_queue_response(cmd);
+	return 0;
+}
+
+static void srpt_queue_tm_rsp(struct se_cmd *cmd)
+{
+	srpt_queue_response(cmd);
+}
+
+/*
+ * This function is called for aborted commands if no response is sent to the
+ * initiator. Make sure that the credits freed by aborting a command are
+ * returned to the initiator the next time a response is sent by incrementing
+ * ch->req_lim_delta.
+ */
+static void srpt_aborted_task(struct se_cmd *cmd)
+{
+	struct srpt_send_ioctx *ioctx = container_of(cmd,
+				struct srpt_send_ioctx, cmd);
+	struct srpt_rdma_ch *ch = ioctx->ch;
+
+	atomic_inc(&ch->req_lim_delta);
+}
+
+static int srpt_queue_status(struct se_cmd *cmd)
+{
+	struct srpt_send_ioctx *ioctx;
+
+	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
+	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
+	if (cmd->se_cmd_flags &
+	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
+		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
+	ioctx->queue_status_only = true;
+	srpt_queue_response(cmd);
+	return 0;
+}
+
+static void srpt_refresh_port_work(struct work_struct *work)
+{
+	struct srpt_port *sport = container_of(work, struct srpt_port, work);
+
+	srpt_refresh_port(sport);
+}
+
+/**
+ * srpt_release_sport - disable login and wait for associated channels
+ * @sport: SRPT HCA port.
+ */
+static int srpt_release_sport(struct srpt_port *sport)
+{
+	DECLARE_COMPLETION_ONSTACK(c);
+	struct srpt_nexus *nexus, *next_n;
+	struct srpt_rdma_ch *ch;
+
+	WARN_ON_ONCE(irqs_disabled());
+
+	sport->freed_channels = &c;
+
+	mutex_lock(&sport->mutex);
+	srpt_set_enabled(sport, false);
+	mutex_unlock(&sport->mutex);
+
+	while (atomic_read(&sport->refcount) > 0 &&
+	       wait_for_completion_timeout(&c, 5 * HZ) <= 0) {
+		pr_info("%s_%d: waiting for unregistration of %d sessions ...\n",
+			dev_name(&sport->sdev->device->dev), sport->port,
+			atomic_read(&sport->refcount));
+		rcu_read_lock();
+		list_for_each_entry(nexus, &sport->nexus_list, entry) {
+			list_for_each_entry(ch, &nexus->ch_list, list) {
+				pr_info("%s-%d: state %s\n",
+					ch->sess_name, ch->qp->qp_num,
+					get_ch_state_name(ch->state));
+			}
+		}
+		rcu_read_unlock();
+	}
+
+	mutex_lock(&sport->mutex);
+	list_for_each_entry_safe(nexus, next_n, &sport->nexus_list, entry) {
+		list_del(&nexus->entry);
+		kfree_rcu(nexus, rcu);
+	}
+	mutex_unlock(&sport->mutex);
+
+	return 0;
+}
+
+struct port_and_port_id {
+	struct srpt_port *sport;
+	struct srpt_port_id **port_id;
+};
+
+static struct port_and_port_id __srpt_lookup_port(const char *name)
+{
+	struct ib_device *dev;
+	struct srpt_device *sdev;
+	struct srpt_port *sport;
+	int i;
+
+	list_for_each_entry(sdev, &srpt_dev_list, list) {
+		dev = sdev->device;
+		if (!dev)
+			continue;
+
+		for (i = 0; i < dev->phys_port_cnt; i++) {
+			sport = &sdev->port[i];
+
+			if (strcmp(sport->guid_name, name) == 0) {
+				kref_get(&sdev->refcnt);
+				return (struct port_and_port_id){
+					sport, &sport->guid_id};
+			}
+			if (strcmp(sport->gid_name, name) == 0) {
+				kref_get(&sdev->refcnt);
+				return (struct port_and_port_id){
+					sport, &sport->gid_id};
+			}
+		}
+	}
+
+	return (struct port_and_port_id){};
+}
+
+/**
+ * srpt_lookup_port() - Look up an RDMA port by name
+ * @name: ASCII port name
+ *
+ * Increments the RDMA port reference count if an RDMA port pointer is returned.
+ * The caller must drop that reference count by calling srpt_port_put_ref().
+ */
+static struct port_and_port_id srpt_lookup_port(const char *name)
+{
+	struct port_and_port_id papi;
+
+	spin_lock(&srpt_dev_lock);
+	papi = __srpt_lookup_port(name);
+	spin_unlock(&srpt_dev_lock);
+
+	return papi;
+}
+
+static void srpt_free_srq(struct srpt_device *sdev)
+{
+	if (!sdev->srq)
+		return;
+
+	ib_destroy_srq(sdev->srq);
+	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
+			     sdev->srq_size, sdev->req_buf_cache,
+			     DMA_FROM_DEVICE);
+	kmem_cache_destroy(sdev->req_buf_cache);
+	sdev->srq = NULL;
+}
+
+static int srpt_alloc_srq(struct srpt_device *sdev)
+{
+	struct ib_srq_init_attr srq_attr = {
+		.event_handler = srpt_srq_event,
+		.srq_context = (void *)sdev,
+		.attr.max_wr = sdev->srq_size,
+		.attr.max_sge = 1,
+		.srq_type = IB_SRQT_BASIC,
+	};
+	struct ib_device *device = sdev->device;
+	struct ib_srq *srq;
+	int i;
+
+	WARN_ON_ONCE(sdev->srq);
+	srq = ib_create_srq(sdev->pd, &srq_attr);
+	if (IS_ERR(srq)) {
+		pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(srq));
+		return PTR_ERR(srq);
+	}
+
+	pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
+		 sdev->device->attrs.max_srq_wr, dev_name(&device->dev));
+
+	sdev->req_buf_cache = kmem_cache_create("srpt-srq-req-buf",
+						srp_max_req_size, 0, 0, NULL);
+	if (!sdev->req_buf_cache)
+		goto free_srq;
+
+	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
+		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
+				      sizeof(*sdev->ioctx_ring[0]),
+				      sdev->req_buf_cache, 0, DMA_FROM_DEVICE);
+	if (!sdev->ioctx_ring)
+		goto free_cache;
+
+	sdev->use_srq = true;
+	sdev->srq = srq;
+
+	for (i = 0; i < sdev->srq_size; ++i) {
+		INIT_LIST_HEAD(&sdev->ioctx_ring[i]->wait_list);
+		srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
+	}
+
+	return 0;
+
+free_cache:
+	kmem_cache_destroy(sdev->req_buf_cache);
+
+free_srq:
+	ib_destroy_srq(srq);
+	return -ENOMEM;
+}
+
+static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
+{
+	struct ib_device *device = sdev->device;
+	int ret = 0;
+
+	if (!use_srq) {
+		srpt_free_srq(sdev);
+		sdev->use_srq = false;
+	} else if (use_srq && !sdev->srq) {
+		ret = srpt_alloc_srq(sdev);
+	}
+	pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__,
+		 dev_name(&device->dev), sdev->use_srq, ret);
+	return ret;
+}
+
+static void srpt_free_sdev(struct kref *refcnt)
+{
+	struct srpt_device *sdev = container_of(refcnt, typeof(*sdev), refcnt);
+
+	kfree(sdev);
+}
+
+static void srpt_sdev_put(struct srpt_device *sdev)
+{
+	kref_put(&sdev->refcnt, srpt_free_sdev);
+}
+
+/**
+ * srpt_add_one - InfiniBand device addition callback function
+ * @device: Describes a HCA.
+ */
+static int srpt_add_one(struct ib_device *device)
+{
+	struct srpt_device *sdev;
+	struct srpt_port *sport;
+	int ret;
+	u32 i;
+
+	pr_debug("device = %p\n", device);
+
+	sdev = kzalloc(struct_size(sdev, port, device->phys_port_cnt),
+		       GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+
+	kref_init(&sdev->refcnt);
+	sdev->device = device;
+	mutex_init(&sdev->sdev_mutex);
+
+	sdev->pd = ib_alloc_pd(device, 0);
+	if (IS_ERR(sdev->pd)) {
+		ret = PTR_ERR(sdev->pd);
+		goto free_dev;
+	}
+
+	sdev->lkey = sdev->pd->local_dma_lkey;
+
+	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
+
+	srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
+
+	if (!srpt_service_guid)
+		srpt_service_guid = be64_to_cpu(device->node_guid);
+
+	if (rdma_port_get_link_layer(device, 1) == IB_LINK_LAYER_INFINIBAND)
+		sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
+	if (IS_ERR(sdev->cm_id)) {
+		pr_info("ib_create_cm_id() failed: %ld\n",
+			PTR_ERR(sdev->cm_id));
+		ret = PTR_ERR(sdev->cm_id);
+		sdev->cm_id = NULL;
+		if (!rdma_cm_id)
+			goto err_ring;
+	}
+
+	/* print out target login information */
+	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,pkey=ffff,service_id=%016llx\n",
+		 srpt_service_guid, srpt_service_guid, srpt_service_guid);
+
+	/*
+	 * We do not have a consistent service_id (ie. also id_ext of target_id)
+	 * to identify this target. We currently use the guid of the first HCA
+	 * in the system as service_id; therefore, the target_id will change
+	 * if this HCA is gone bad and replaced by different HCA
+	 */
+	ret = sdev->cm_id ?
+		ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid)) :
+		0;
+	if (ret < 0) {
+		pr_err("ib_cm_listen() failed: %d (cm_id state = %d)\n", ret,
+		       sdev->cm_id->state);
+		goto err_cm;
+	}
+
+	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
+			      srpt_event_handler);
+	ib_register_event_handler(&sdev->event_handler);
+
+	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
+		sport = &sdev->port[i - 1];
+		INIT_LIST_HEAD(&sport->nexus_list);
+		mutex_init(&sport->mutex);
+		sport->sdev = sdev;
+		sport->port = i;
+		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
+		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
+		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
+		sport->port_attrib.use_srq = false;
+		INIT_WORK(&sport->work, srpt_refresh_port_work);
+
+		ret = srpt_refresh_port(sport);
+		if (ret) {
+			pr_err("MAD registration failed for %s-%d.\n",
+			       dev_name(&sdev->device->dev), i);
+			i--;
+			goto err_port;
+		}
+	}
+
+	spin_lock(&srpt_dev_lock);
+	list_add_tail(&sdev->list, &srpt_dev_list);
+	spin_unlock(&srpt_dev_lock);
+
+	ib_set_client_data(device, &srpt_client, sdev);
+	pr_debug("added %s.\n", dev_name(&device->dev));
+	return 0;
+
+err_port:
+	srpt_unregister_mad_agent(sdev, i);
+	ib_unregister_event_handler(&sdev->event_handler);
+err_cm:
+	if (sdev->cm_id)
+		ib_destroy_cm_id(sdev->cm_id);
+err_ring:
+	srpt_free_srq(sdev);
+	ib_dealloc_pd(sdev->pd);
+free_dev:
+	srpt_sdev_put(sdev);
+	pr_info("%s(%s) failed.\n", __func__, dev_name(&device->dev));
+	return ret;
+}
+
+/**
+ * srpt_remove_one - InfiniBand device removal callback function
+ * @device: Describes a HCA.
+ * @client_data: The value passed as the third argument to ib_set_client_data().
+ */
+static void srpt_remove_one(struct ib_device *device, void *client_data)
+{
+	struct srpt_device *sdev = client_data;
+	int i;
+
+	srpt_unregister_mad_agent(sdev, sdev->device->phys_port_cnt);
+
+	ib_unregister_event_handler(&sdev->event_handler);
+
+	/* Cancel any work queued by the just unregistered IB event handler. */
+	for (i = 0; i < sdev->device->phys_port_cnt; i++)
+		cancel_work_sync(&sdev->port[i].work);
+
+	if (sdev->cm_id)
+		ib_destroy_cm_id(sdev->cm_id);
+
+	ib_set_client_data(device, &srpt_client, NULL);
+
+	/*
+	 * Unregistering a target must happen after destroying sdev->cm_id
+	 * such that no new SRP_LOGIN_REQ information units can arrive while
+	 * destroying the target.
+	 */
+	spin_lock(&srpt_dev_lock);
+	list_del(&sdev->list);
+	spin_unlock(&srpt_dev_lock);
+
+	for (i = 0; i < sdev->device->phys_port_cnt; i++)
+		srpt_release_sport(&sdev->port[i]);
+
+	srpt_free_srq(sdev);
+
+	ib_dealloc_pd(sdev->pd);
+
+	srpt_sdev_put(sdev);
+}
+
+static struct ib_client srpt_client = {
+	.name = DRV_NAME,
+	.add = srpt_add_one,
+	.remove = srpt_remove_one
+};
+
+static int srpt_check_true(struct se_portal_group *se_tpg)
+{
+	return 1;
+}
+
+static int srpt_check_false(struct se_portal_group *se_tpg)
+{
+	return 0;
+}
+
+static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
+{
+	return tpg->se_tpg_wwn->priv;
+}
+
+static struct srpt_port_id *srpt_wwn_to_sport_id(struct se_wwn *wwn)
+{
+	struct srpt_port *sport = wwn->priv;
+
+	if (sport->guid_id && &sport->guid_id->wwn == wwn)
+		return sport->guid_id;
+	if (sport->gid_id && &sport->gid_id->wwn == wwn)
+		return sport->gid_id;
+	WARN_ON_ONCE(true);
+	return NULL;
+}
+
+static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
+{
+	struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
+
+	return stpg->sport_id->name;
+}
+
+static u16 srpt_get_tag(struct se_portal_group *tpg)
+{
+	return 1;
+}
+
+static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
+{
+	return 1;
+}
+
+static void srpt_release_cmd(struct se_cmd *se_cmd)
+{
+	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
+				struct srpt_send_ioctx, cmd);
+	struct srpt_rdma_ch *ch = ioctx->ch;
+	struct srpt_recv_ioctx *recv_ioctx = ioctx->recv_ioctx;
+
+	WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
+		     !(ioctx->cmd.transport_state & CMD_T_ABORTED));
+
+	if (recv_ioctx) {
+		WARN_ON_ONCE(!list_empty(&recv_ioctx->wait_list));
+		ioctx->recv_ioctx = NULL;
+		srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
+	}
+
+	if (ioctx->n_rw_ctx) {
+		srpt_free_rw_ctxs(ch, ioctx);
+		ioctx->n_rw_ctx = 0;
+	}
+
+	target_free_tag(se_cmd->se_sess, se_cmd);
+}
+
+/**
+ * srpt_close_session - forcibly close a session
+ * @se_sess: SCSI target session.
+ *
+ * Callback function invoked by the TCM core to clean up sessions associated
+ * with a node ACL when the user invokes
+ * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
+ */
+static void srpt_close_session(struct se_session *se_sess)
+{
+	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
+
+	srpt_disconnect_ch_sync(ch);
+}
+
+/**
+ * srpt_sess_get_index - return the value of scsiAttIntrPortIndex (SCSI-MIB)
+ * @se_sess: SCSI target session.
+ *
+ * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
+ * This object represents an arbitrary integer used to uniquely identify a
+ * particular attached remote initiator port to a particular SCSI target port
+ * within a particular SCSI target device within a particular SCSI instance.
+ */
+static u32 srpt_sess_get_index(struct se_session *se_sess)
+{
+	return 0;
+}
+
+static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
+{
+}
+
+/* Note: only used from inside debug printk's by the TCM core. */
+static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
+{
+	struct srpt_send_ioctx *ioctx;
+
+	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
+	return ioctx->state;
+}
+
+static int srpt_parse_guid(u64 *guid, const char *name)
+{
+	u16 w[4];
+	int ret = -EINVAL;
+
+	if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
+		goto out;
+	*guid = get_unaligned_be64(w);
+	ret = 0;
+out:
+	return ret;
+}
+
+/**
+ * srpt_parse_i_port_id - parse an initiator port ID
+ * @name: ASCII representation of a 128-bit initiator port ID.
+ * @i_port_id: Binary 128-bit port ID.
+ */
+static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
+{
+	const char *p;
+	unsigned len, count, leading_zero_bytes;
+	int ret;
+
+	p = name;
+	if (strncasecmp(p, "0x", 2) == 0)
+		p += 2;
+	ret = -EINVAL;
+	len = strlen(p);
+	if (len % 2)
+		goto out;
+	count = min(len / 2, 16U);
+	leading_zero_bytes = 16 - count;
+	memset(i_port_id, 0, leading_zero_bytes);
+	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
+
+out:
+	return ret;
+}
+
+/*
+ * configfs callback function invoked for mkdir
+ * /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
+ *
+ * i_port_id must be an initiator port GUID, GID or IP address. See also the
+ * target_alloc_session() calls in this driver. Examples of valid initiator
+ * port IDs:
+ * 0x0000000000000000505400fffe4a0b7b
+ * 0000000000000000505400fffe4a0b7b
+ * 5054:00ff:fe4a:0b7b
+ * 192.168.122.76
+ */
+static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
+{
+	struct sockaddr_storage sa;
+	u64 guid;
+	u8 i_port_id[16];
+	int ret;
+
+	ret = srpt_parse_guid(&guid, name);
+	if (ret < 0)
+		ret = srpt_parse_i_port_id(i_port_id, name);
+	if (ret < 0)
+		ret = inet_pton_with_scope(&init_net, AF_UNSPEC, name, NULL,
+					   &sa);
+	if (ret < 0)
+		pr_err("invalid initiator port ID %s\n", name);
+	return ret;
+}
+
+static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
+		char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
+}
+
+static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(page, 0, &val);
+	if (ret < 0) {
+		pr_err("kstrtoul() failed with ret: %d\n", ret);
+		return -EINVAL;
+	}
+	if (val > MAX_SRPT_RDMA_SIZE) {
+		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
+			MAX_SRPT_RDMA_SIZE);
+		return -EINVAL;
+	}
+	if (val < DEFAULT_MAX_RDMA_SIZE) {
+		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
+			val, DEFAULT_MAX_RDMA_SIZE);
+		return -EINVAL;
+	}
+	sport->port_attrib.srp_max_rdma_size = val;
+
+	return count;
+}
+
+static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
+		char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
+}
+
+static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(page, 0, &val);
+	if (ret < 0) {
+		pr_err("kstrtoul() failed with ret: %d\n", ret);
+		return -EINVAL;
+	}
+	if (val > MAX_SRPT_RSP_SIZE) {
+		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
+			MAX_SRPT_RSP_SIZE);
+		return -EINVAL;
+	}
+	if (val < MIN_MAX_RSP_SIZE) {
+		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
+			MIN_MAX_RSP_SIZE);
+		return -EINVAL;
+	}
+	sport->port_attrib.srp_max_rsp_size = val;
+
+	return count;
+}
+
+static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
+		char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_sq_size);
+}
+
+static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(page, 0, &val);
+	if (ret < 0) {
+		pr_err("kstrtoul() failed with ret: %d\n", ret);
+		return -EINVAL;
+	}
+	if (val > MAX_SRPT_SRQ_SIZE) {
+		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
+			MAX_SRPT_SRQ_SIZE);
+		return -EINVAL;
+	}
+	if (val < MIN_SRPT_SRQ_SIZE) {
+		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
+			MIN_SRPT_SRQ_SIZE);
+		return -EINVAL;
+	}
+	sport->port_attrib.srp_sq_size = val;
+
+	return count;
+}
+
+static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
+					    char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	return sysfs_emit(page, "%d\n", sport->port_attrib.use_srq);
+}
+
+static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+	struct srpt_device *sdev = sport->sdev;
+	unsigned long val;
+	bool enabled;
+	int ret;
+
+	ret = kstrtoul(page, 0, &val);
+	if (ret < 0)
+		return ret;
+	if (val != !!val)
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&sdev->sdev_mutex);
+	if (ret < 0)
+		return ret;
+	ret = mutex_lock_interruptible(&sport->mutex);
+	if (ret < 0)
+		goto unlock_sdev;
+	enabled = sport->enabled;
+	/* Log out all initiator systems before changing 'use_srq'. */
+	srpt_set_enabled(sport, false);
+	sport->port_attrib.use_srq = val;
+	srpt_use_srq(sdev, sport->port_attrib.use_srq);
+	srpt_set_enabled(sport, enabled);
+	ret = count;
+	mutex_unlock(&sport->mutex);
+unlock_sdev:
+	mutex_unlock(&sdev->sdev_mutex);
+
+	return ret;
+}
+
+CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
+CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
+CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
+CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
+
+static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
+	&srpt_tpg_attrib_attr_srp_max_rdma_size,
+	&srpt_tpg_attrib_attr_srp_max_rsp_size,
+	&srpt_tpg_attrib_attr_srp_sq_size,
+	&srpt_tpg_attrib_attr_use_srq,
+	NULL,
+};
+
+static struct rdma_cm_id *srpt_create_rdma_id(struct sockaddr *listen_addr)
+{
+	struct rdma_cm_id *rdma_cm_id;
+	int ret;
+
+	rdma_cm_id = rdma_create_id(&init_net, srpt_rdma_cm_handler,
+				    NULL, RDMA_PS_TCP, IB_QPT_RC);
+	if (IS_ERR(rdma_cm_id)) {
+		pr_err("RDMA/CM ID creation failed: %ld\n",
+		       PTR_ERR(rdma_cm_id));
+		goto out;
+	}
+
+	ret = rdma_bind_addr(rdma_cm_id, listen_addr);
+	if (ret) {
+		char addr_str[64];
+
+		snprintf(addr_str, sizeof(addr_str), "%pISp", listen_addr);
+		pr_err("Binding RDMA/CM ID to address %s failed: %d\n",
+		       addr_str, ret);
+		rdma_destroy_id(rdma_cm_id);
+		rdma_cm_id = ERR_PTR(ret);
+		goto out;
+	}
+
+	ret = rdma_listen(rdma_cm_id, 128);
+	if (ret) {
+		pr_err("rdma_listen() failed: %d\n", ret);
+		rdma_destroy_id(rdma_cm_id);
+		rdma_cm_id = ERR_PTR(ret);
+	}
+
+out:
+	return rdma_cm_id;
+}
+
+static ssize_t srpt_rdma_cm_port_show(struct config_item *item, char *page)
+{
+	return sysfs_emit(page, "%d\n", rdma_cm_port);
+}
+
+static ssize_t srpt_rdma_cm_port_store(struct config_item *item,
+				       const char *page, size_t count)
+{
+	struct sockaddr_in  addr4 = { .sin_family  = AF_INET  };
+	struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6 };
+	struct rdma_cm_id *new_id = NULL;
+	u16 val;
+	int ret;
+
+	ret = kstrtou16(page, 0, &val);
+	if (ret < 0)
+		return ret;
+	ret = count;
+	if (rdma_cm_port == val)
+		goto out;
+
+	if (val) {
+		addr6.sin6_port = cpu_to_be16(val);
+		new_id = srpt_create_rdma_id((struct sockaddr *)&addr6);
+		if (IS_ERR(new_id)) {
+			addr4.sin_port = cpu_to_be16(val);
+			new_id = srpt_create_rdma_id((struct sockaddr *)&addr4);
+			if (IS_ERR(new_id)) {
+				ret = PTR_ERR(new_id);
+				goto out;
+			}
+		}
+	}
+
+	mutex_lock(&rdma_cm_mutex);
+	rdma_cm_port = val;
+	swap(rdma_cm_id, new_id);
+	mutex_unlock(&rdma_cm_mutex);
+
+	if (new_id)
+		rdma_destroy_id(new_id);
+	ret = count;
+out:
+	return ret;
+}
+
+CONFIGFS_ATTR(srpt_, rdma_cm_port);
+
+static struct configfs_attribute *srpt_da_attrs[] = {
+	&srpt_attr_rdma_cm_port,
+	NULL,
+};
+
+static int srpt_enable_tpg(struct se_portal_group *se_tpg, bool enable)
+{
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	mutex_lock(&sport->mutex);
+	srpt_set_enabled(sport, enable);
+	mutex_unlock(&sport->mutex);
+
+	return 0;
+}
+
+/**
+ * srpt_make_tpg - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port/$tpg
+ * @wwn: Corresponds to $driver/$port.
+ * @name: $tpg.
+ */
+static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
+					     const char *name)
+{
+	struct srpt_port_id *sport_id = srpt_wwn_to_sport_id(wwn);
+	struct srpt_tpg *stpg;
+	int res = -ENOMEM;
+
+	stpg = kzalloc(sizeof(*stpg), GFP_KERNEL);
+	if (!stpg)
+		return ERR_PTR(res);
+	stpg->sport_id = sport_id;
+	res = core_tpg_register(wwn, &stpg->tpg, SCSI_PROTOCOL_SRP);
+	if (res) {
+		kfree(stpg);
+		return ERR_PTR(res);
+	}
+
+	mutex_lock(&sport_id->mutex);
+	list_add_tail(&stpg->entry, &sport_id->tpg_list);
+	mutex_unlock(&sport_id->mutex);
+
+	return &stpg->tpg;
+}
+
+/**
+ * srpt_drop_tpg - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port/$tpg
+ * @tpg: Target portal group to deregister.
+ */
+static void srpt_drop_tpg(struct se_portal_group *tpg)
+{
+	struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
+	struct srpt_port_id *sport_id = stpg->sport_id;
+	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
+
+	mutex_lock(&sport_id->mutex);
+	list_del(&stpg->entry);
+	mutex_unlock(&sport_id->mutex);
+
+	sport->enabled = false;
+	core_tpg_deregister(tpg);
+	kfree(stpg);
+}
+
+/**
+ * srpt_make_tport - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port
+ * @tf: Not used.
+ * @group: Not used.
+ * @name: $port.
+ */
+static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
+				      struct config_group *group,
+				      const char *name)
+{
+	struct port_and_port_id papi = srpt_lookup_port(name);
+	struct srpt_port *sport = papi.sport;
+	struct srpt_port_id *port_id;
+
+	if (!papi.port_id)
+		return ERR_PTR(-EINVAL);
+	if (*papi.port_id) {
+		/* Attempt to create a directory that already exists. */
+		WARN_ON_ONCE(true);
+		return &(*papi.port_id)->wwn;
+	}
+	port_id = kzalloc(sizeof(*port_id), GFP_KERNEL);
+	if (!port_id) {
+		srpt_sdev_put(sport->sdev);
+		return ERR_PTR(-ENOMEM);
+	}
+	mutex_init(&port_id->mutex);
+	INIT_LIST_HEAD(&port_id->tpg_list);
+	port_id->wwn.priv = sport;
+	memcpy(port_id->name, port_id == sport->guid_id ? sport->guid_name :
+	       sport->gid_name, ARRAY_SIZE(port_id->name));
+
+	*papi.port_id = port_id;
+
+	return &port_id->wwn;
+}
+
+/**
+ * srpt_drop_tport - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port
+ * @wwn: $port.
+ */
+static void srpt_drop_tport(struct se_wwn *wwn)
+{
+	struct srpt_port_id *port_id = container_of(wwn, typeof(*port_id), wwn);
+	struct srpt_port *sport = wwn->priv;
+
+	if (sport->guid_id == port_id)
+		sport->guid_id = NULL;
+	else if (sport->gid_id == port_id)
+		sport->gid_id = NULL;
+	else
+		WARN_ON_ONCE(true);
+
+	srpt_sdev_put(sport->sdev);
+	kfree(port_id);
+}
+
+static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
+{
+	return sysfs_emit(buf, "\n");
+}
+
+CONFIGFS_ATTR_RO(srpt_wwn_, version);
+
+static struct configfs_attribute *srpt_wwn_attrs[] = {
+	&srpt_wwn_attr_version,
+	NULL,
+};
+
+static const struct target_core_fabric_ops srpt_template = {
+	.module				= THIS_MODULE,
+	.fabric_name			= "srpt",
+	.tpg_get_wwn			= srpt_get_fabric_wwn,
+	.tpg_get_tag			= srpt_get_tag,
+	.tpg_check_demo_mode		= srpt_check_false,
+	.tpg_check_demo_mode_cache	= srpt_check_true,
+	.tpg_check_demo_mode_write_protect = srpt_check_true,
+	.tpg_check_prod_mode_write_protect = srpt_check_false,
+	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
+	.release_cmd			= srpt_release_cmd,
+	.check_stop_free		= srpt_check_stop_free,
+	.close_session			= srpt_close_session,
+	.sess_get_index			= srpt_sess_get_index,
+	.sess_get_initiator_sid		= NULL,
+	.write_pending			= srpt_write_pending,
+	.set_default_node_attributes	= srpt_set_default_node_attrs,
+	.get_cmd_state			= srpt_get_tcm_cmd_state,
+	.queue_data_in			= srpt_queue_data_in,
+	.queue_status			= srpt_queue_status,
+	.queue_tm_rsp			= srpt_queue_tm_rsp,
+	.aborted_task			= srpt_aborted_task,
+	/*
+	 * Setup function pointers for generic logic in
+	 * target_core_fabric_configfs.c
+	 */
+	.fabric_make_wwn		= srpt_make_tport,
+	.fabric_drop_wwn		= srpt_drop_tport,
+	.fabric_make_tpg		= srpt_make_tpg,
+	.fabric_enable_tpg		= srpt_enable_tpg,
+	.fabric_drop_tpg		= srpt_drop_tpg,
+	.fabric_init_nodeacl		= srpt_init_nodeacl,
+
+	.tfc_discovery_attrs		= srpt_da_attrs,
+	.tfc_wwn_attrs			= srpt_wwn_attrs,
+	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
+};
+
+/**
+ * srpt_init_module - kernel module initialization
+ *
+ * Note: Since ib_register_client() registers callback functions, and since at
+ * least one of these callback functions (srpt_add_one()) calls target core
+ * functions, this driver must be registered with the target core before
+ * ib_register_client() is called.
+ */
+static int __init srpt_init_module(void)
+{
+	int ret;
+
+	ret = -EINVAL;
+	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
+		pr_err("invalid value %d for kernel module parameter srp_max_req_size -- must be at least %d.\n",
+		       srp_max_req_size, MIN_MAX_REQ_SIZE);
+		goto out;
+	}
+
+	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
+	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
+		pr_err("invalid value %d for kernel module parameter srpt_srq_size -- must be in the range [%d..%d].\n",
+		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
+		goto out;
+	}
+
+	ret = target_register_template(&srpt_template);
+	if (ret)
+		goto out;
+
+	ret = ib_register_client(&srpt_client);
+	if (ret) {
+		pr_err("couldn't register IB client\n");
+		goto out_unregister_target;
+	}
+
+	return 0;
+
+out_unregister_target:
+	target_unregister_template(&srpt_template);
+out:
+	return ret;
+}
+
+static void __exit srpt_cleanup_module(void)
+{
+	if (rdma_cm_id)
+		rdma_destroy_id(rdma_cm_id);
+	ib_unregister_client(&srpt_client);
+	target_unregister_template(&srpt_template);
+}
+
+module_init(srpt_init_module);
+module_exit(srpt_cleanup_module);