[RFC] ib_srpt: initial .40-rc1 drivers/infiniband/ulp/srpt merge

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

Hi Roland, Bart and Co,

This patch adds the kernel module ib_srpt SCSI RDMA Protocol (SRP) target
implementation conforming to the SRP r16a specification.

This driver was originally developed by Vu Pham and has been optimized by
Bart Van Assche and merged into upstream LIO based on his srpt-lio-4.1
branch here:

   https://github.com/bvanassche/srpt-lio/commits/srpt-lio-4.1/

This updated patch also contains the following two changes from
lio-core-2.6.git/lio-4.1.  One is to fix a bug with 1 >= task->task_sg[]
chained mappings in ib_srpt, and the other to convert the configfs control
plane to reference IB Port GUID and struct srpt_port directly following
mainline v4.0 target_core_fabric_configfs.c convertion for ib_srpt
to work with rtslib/rtsadmin v2 code.

These seperate patches can be found here:

ib_srpt: Fix bug with chainged SGLs in srpt_map_sg_to_ib_sge
http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=commitdiff;h=ea485147563b6555a97dbf811825fbb586519252

ib_srpt: Convert se_wwn endpoint reference to struct srpt_port->port_wwn
http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=commitdiff;h=4e544a210acb227df1bb4ca5086e65bdf4e648ea

Note that this series requires the following four part patch series for
mainline target core in order to function, which are currently in James's
scsi-misc queue, which can be found here:

[PATCH-v2 0/4] Bugfixes for .39-rc8
http://marc.info/?l=linux-scsi&m=130514011321906&w=2

Also for convenience, this patch along with the proper mainline target core
patches above are directly here @ .39-rc7:

   git://git.kernel.org/pub/scm/linux/kernel/git/nab/scsi-post-merge-2.6.git for-40-ib_srpt

Please review+consider for an initial merge, and thanks to Bart Van Assche
for his efforts to forward port driver to mainline target v4 infrastructure.

Bart, can you please review the changes and add your signoff if you are OK
with the bugfix and control plane rework..?

Thanks everyone,

Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/Kconfig              |    1 +
 drivers/infiniband/Makefile             |    1 +
 drivers/infiniband/ulp/srpt/Kconfig     |   12 +
 drivers/infiniband/ulp/srpt/Makefile    |    2 +
 drivers/infiniband/ulp/srpt/ib_dm_mad.h |  139 ++
 drivers/infiniband/ulp/srpt/ib_srpt.c   | 4001 +++++++++++++++++++++++++++++++
 drivers/infiniband/ulp/srpt/ib_srpt.h   |  409 ++++
 7 files changed, 4565 insertions(+), 0 deletions(-)
 create mode 100644 drivers/infiniband/ulp/srpt/Kconfig
 create mode 100644 drivers/infiniband/ulp/srpt/Makefile
 create mode 100644 drivers/infiniband/ulp/srpt/ib_dm_mad.h
 create mode 100644 drivers/infiniband/ulp/srpt/ib_srpt.c
 create mode 100644 drivers/infiniband/ulp/srpt/ib_srpt.h

diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig
index 6e35ecc..e1eadb5 100644
--- a/drivers/infiniband/Kconfig
+++ b/drivers/infiniband/Kconfig
@@ -54,6 +54,7 @@ source "drivers/infiniband/hw/nes/Kconfig"
 source "drivers/infiniband/ulp/ipoib/Kconfig"
 
 source "drivers/infiniband/ulp/srp/Kconfig"
+source "drivers/infiniband/ulp/srpt/Kconfig"
 
 source "drivers/infiniband/ulp/iser/Kconfig"
 
diff --git a/drivers/infiniband/Makefile b/drivers/infiniband/Makefile
index 9cc7a47..a3b2d8e 100644
--- a/drivers/infiniband/Makefile
+++ b/drivers/infiniband/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_MLX4_INFINIBAND)		+= hw/mlx4/
 obj-$(CONFIG_INFINIBAND_NES)		+= hw/nes/
 obj-$(CONFIG_INFINIBAND_IPOIB)		+= ulp/ipoib/
 obj-$(CONFIG_INFINIBAND_SRP)		+= ulp/srp/
+obj-$(CONFIG_INFINIBAND_SRPT)		+= ulp/srpt/
 obj-$(CONFIG_INFINIBAND_ISER)		+= ulp/iser/
diff --git a/drivers/infiniband/ulp/srpt/Kconfig b/drivers/infiniband/ulp/srpt/Kconfig
new file mode 100644
index 0000000..31ee83d
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/Kconfig
@@ -0,0 +1,12 @@
+config INFINIBAND_SRPT
+	tristate "InfiniBand SCSI RDMA Protocol target support"
+	depends on INFINIBAND && TARGET_CORE
+	---help---
+
+	  Support for the SCSI RDMA Protocol (SRP) Target driver. The
+	  SRP protocol is a protocol that allows an initiator to access
+	  a block storage device on another host (target) over a network
+	  that supports the RDMA protocol. Currently the RDMA protocol is
+	  supported by InfiniBand and by iWarp network hardware. More
+	  information about the SRP protocol can be found on the website
+	  of the INCITS T10 technical committee (http://www.t10.org/).
diff --git a/drivers/infiniband/ulp/srpt/Makefile b/drivers/infiniband/ulp/srpt/Makefile
new file mode 100644
index 0000000..e3ee4bd
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/Makefile
@@ -0,0 +1,2 @@
+ccflags-y			:= -Idrivers/target
+obj-$(CONFIG_INFINIBAND_SRPT)	+= ib_srpt.o
diff --git a/drivers/infiniband/ulp/srpt/ib_dm_mad.h b/drivers/infiniband/ulp/srpt/ib_dm_mad.h
new file mode 100644
index 0000000..fb1de1f
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/ib_dm_mad.h
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#ifndef IB_DM_MAD_H
+#define IB_DM_MAD_H
+
+#include <linux/types.h>
+
+#include <rdma/ib_mad.h>
+
+enum {
+	/*
+	 * See also section 13.4.7 Status Field, table 115 MAD Common Status
+	 * Field Bit Values and also section 16.3.1.1 Status Field in the
+	 * InfiniBand Architecture Specification.
+	 */
+	DM_MAD_STATUS_UNSUP_METHOD = 0x0008,
+	DM_MAD_STATUS_UNSUP_METHOD_ATTR = 0x000c,
+	DM_MAD_STATUS_INVALID_FIELD = 0x001c,
+	DM_MAD_STATUS_NO_IOC = 0x0100,
+
+	/*
+	 * See also the Device Management chapter, section 16.3.3 Attributes,
+	 * table 279 Device Management Attributes in the InfiniBand
+	 * Architecture Specification.
+	 */
+	DM_ATTR_CLASS_PORT_INFO = 0x01,
+	DM_ATTR_IOU_INFO = 0x10,
+	DM_ATTR_IOC_PROFILE = 0x11,
+	DM_ATTR_SVC_ENTRIES = 0x12
+};
+
+struct ib_dm_hdr {
+	u8 reserved[28];
+};
+
+/*
+ * Structure of management datagram sent by the SRP target implementation.
+ * Contains a management datagram header, reliable multi-packet transaction
+ * protocol (RMPP) header and ib_dm_hdr. Notes:
+ * - The SRP target implementation does not use RMPP or ib_dm_hdr when sending
+ *   management datagrams.
+ * - The header size must be exactly 64 bytes (IB_MGMT_DEVICE_HDR), since this
+ *   is the header size that is passed to ib_create_send_mad() in ib_srpt.c.
+ * - The maximum supported size for a management datagram when not using RMPP
+ *   is 256 bytes -- 64 bytes header and 192 (IB_MGMT_DEVICE_DATA) bytes data.
+ */
+struct ib_dm_mad {
+	struct ib_mad_hdr mad_hdr;
+	struct ib_rmpp_hdr rmpp_hdr;
+	struct ib_dm_hdr dm_hdr;
+	u8 data[IB_MGMT_DEVICE_DATA];
+};
+
+/*
+ * IOUnitInfo as defined in section 16.3.3.3 IOUnitInfo of the InfiniBand
+ * Architecture Specification.
+ */
+struct ib_dm_iou_info {
+	__be16 change_id;
+	u8 max_controllers;
+	u8 op_rom;
+	u8 controller_list[128];
+};
+
+/*
+ * IOControllerprofile as defined in section 16.3.3.4 IOControllerProfile of
+ * the InfiniBand Architecture Specification.
+ */
+struct ib_dm_ioc_profile {
+	__be64 guid;
+	__be32 vendor_id;
+	__be32 device_id;
+	__be16 device_version;
+	__be16 reserved1;
+	__be32 subsys_vendor_id;
+	__be32 subsys_device_id;
+	__be16 io_class;
+	__be16 io_subclass;
+	__be16 protocol;
+	__be16 protocol_version;
+	__be16 service_conn;
+	__be16 initiators_supported;
+	__be16 send_queue_depth;
+	u8 reserved2;
+	u8 rdma_read_depth;
+	__be32 send_size;
+	__be32 rdma_size;
+	u8 op_cap_mask;
+	u8 svc_cap_mask;
+	u8 num_svc_entries;
+	u8 reserved3[9];
+	u8 id_string[64];
+};
+
+struct ib_dm_svc_entry {
+	u8 name[40];
+	__be64 id;
+};
+
+/*
+ * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
+ * Specification. See also section B.7, table B.8 in the T10 SRP r16a document.
+ */
+struct ib_dm_svc_entries {
+	struct ib_dm_svc_entry service_entries[4];
+};
+
+#endif
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
new file mode 100644
index 0000000..83d4ef8
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -0,0 +1,4001 @@
+/*
+ * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
+ * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@xxxxxxx>.
+ *
+ * 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 <scsi/libsas.h> /* TASK_ATTR_* */
+#include <target/configfs_macros.h>
+#include <target/target_core_base.h>
+#include <target/target_core_base.h>
+#include <target/target_core_device.h>
+#include <target/target_core_fabric_configfs.h>
+#include <target/target_core_fabric_lib.h>
+#include <target/target_core_fabric_ops.h>
+#include <target/target_core_tmr.h>
+#include <target/target_core_tpg.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_configfs.h>
+#include "ib_srpt.h"
+
+/* Name of this kernel module. */
+#define DRV_NAME		"ib_srpt"
+#define DRV_VERSION		"2.0.0"
+#define DRV_RELDATE		"2011-02-14"
+
+#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("InfiniBand SCSI RDMA Protocol target "
+		   "v" DRV_VERSION " (" DRV_RELDATE ")");
+MODULE_LICENSE("Dual BSD/GPL");
+
+/*
+ * Global Variables
+ */
+
+static u64 srpt_service_guid;
+static spinlock_t srpt_dev_lock;       /* Protects srpt_dev_list. */
+static struct list_head srpt_dev_list; /* List of srpt_device structures. */
+
+static unsigned srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
+module_param(srp_max_rdma_size, int, 0744);
+MODULE_PARM_DESC(srp_max_rdma_size,
+		 "Maximum size of SRP RDMA transfers for new connections.");
+
+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 unsigned int srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
+module_param(srp_max_rsp_size, int, 0444);
+MODULE_PARM_DESC(srp_max_rsp_size,
+		 "Maximum size of SRP response 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_sq_size = DEF_SRPT_SQ_SIZE;
+module_param(srpt_sq_size, int, 0444);
+MODULE_PARM_DESC(srpt_sq_size,
+		 "Per-channel send queue (SQ) size.");
+
+static bool use_port_guid_in_session_name;
+module_param(use_port_guid_in_session_name, bool, 0444);
+MODULE_PARM_DESC(use_port_guid_in_session_name,
+		 "Use target port ID in the session name such that"
+		 " redundant paths between multiport systems can be masked.");
+
+static int srpt_get_u64_x(char *buffer, struct kernel_param *kp)
+{
+	return sprintf(buffer, "0x%016llx", *(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;
+static struct target_fabric_configfs *srpt_target;
+static void srpt_release_channel(struct srpt_rdma_ch *ch);
+static int srpt_queue_status(struct se_cmd *cmd);
+
+/**
+ * opposite_dma_dir() - Swap DMA_TO_DEVICE and DMA_FROM_DEVICE.
+ */
+static inline
+enum dma_data_direction opposite_dma_dir(enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_TO_DEVICE:	return DMA_FROM_DEVICE;
+	case DMA_FROM_DEVICE:	return DMA_TO_DEVICE;
+	default:		return dir;
+	}
+}
+
+/**
+ * srpt_sdev_name() - Return the name associated with the HCA.
+ *
+ * Examples are ib0, ib1, ...
+ */
+static inline const char *srpt_sdev_name(struct srpt_device *sdev)
+{
+	return sdev->device->name;
+}
+
+static enum rdma_ch_state srpt_get_ch_state(struct srpt_rdma_ch *ch)
+{
+	unsigned long flags;
+	enum rdma_ch_state state;
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	state = ch->state;
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+	return state;
+}
+
+static enum rdma_ch_state
+srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new_state)
+{
+	unsigned long flags;
+	enum rdma_ch_state prev;
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	prev = ch->state;
+	ch->state = new_state;
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+	return prev;
+}
+
+/**
+ * srpt_test_and_set_ch_state() - Test and set the channel state.
+ *
+ * Returns true if and only if the channel state has been set to the new state.
+ */
+static bool
+srpt_test_and_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state old,
+			   enum rdma_ch_state new)
+{
+	unsigned long flags;
+	enum rdma_ch_state prev;
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	prev = ch->state;
+	if (prev == old)
+		ch->state = new;
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+	return prev == old;
+}
+
+/**
+ * srpt_event_handler() - Asynchronous IB event callback function.
+ *
+ * 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;
+	struct srpt_port *sport;
+
+	sdev = ib_get_client_data(event->device, &srpt_client);
+	if (!sdev || sdev->device != event->device)
+		return;
+
+	pr_debug("ASYNC event= %d on device= %s\n", event->event,
+		 srpt_sdev_name(sdev));
+
+	switch (event->event) {
+	case IB_EVENT_PORT_ERR:
+		if (event->element.port_num <= sdev->device->phys_port_cnt) {
+			sport = &sdev->port[event->element.port_num - 1];
+			sport->lid = 0;
+			sport->sm_lid = 0;
+		}
+		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:
+		/* Refresh port data asynchronously. */
+		if (event->element.port_num <= sdev->device->phys_port_cnt) {
+			sport = &sdev->port[event->element.port_num - 1];
+			if (!sport->lid && !sport->sm_lid)
+				schedule_work(&sport->work);
+		}
+		break;
+	default:
+		printk(KERN_ERR "received unrecognized IB event %d\n",
+		       event->event);
+		break;
+	}
+}
+
+/**
+ * srpt_srq_event() - SRQ event callback function.
+ */
+static void srpt_srq_event(struct ib_event *event, void *ctx)
+{
+	printk(KERN_INFO "SRQ event %d\n", event->event);
+}
+
+/**
+ * srpt_qp_event() - QP event callback function.
+ */
+static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
+{
+	pr_debug("QP event %d on cm_id=%p sess_name=%s state=%d\n",
+		 event->event, ch->cm_id, ch->sess_name, srpt_get_ch_state(ch));
+
+	switch (event->event) {
+	case IB_EVENT_COMM_EST:
+		ib_cm_notify(ch->cm_id, event->event);
+		break;
+	case IB_EVENT_QP_LAST_WQE_REACHED:
+		if (srpt_test_and_set_ch_state(ch, CH_DRAINING,
+					       CH_RELEASING))
+			srpt_release_channel(ch);
+		else
+			pr_debug("%s: state %d - ignored LAST_WQE.\n",
+				 ch->sess_name, srpt_get_ch_state(ch));
+		break;
+	default:
+		printk(KERN_ERR "received unrecognized IB QP event %d\n",
+		       event->event);
+		break;
+	}
+}
+
+/**
+ * srpt_set_ioc() - Helper function for initializing an IOUnitInfo structure.
+ *
+ * @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.
+ *
+ * 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;
+	cif->resp_time_value = 20;
+
+	mad->mad_hdr.status = 0;
+}
+
+/**
+ * srpt_get_iou() - Write IOUnitInfo to a management datagram.
+ *
+ * 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 = __constant_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.
+ *
+ * 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_device *sdev, u32 slot,
+			 struct ib_dm_mad *mad)
+{
+	struct ib_dm_ioc_profile *iocp;
+
+	iocp = (struct ib_dm_ioc_profile *)mad->data;
+
+	if (!slot || slot > 16) {
+		mad->mad_hdr.status
+			= __constant_cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
+		return;
+	}
+
+	if (slot > 2) {
+		mad->mad_hdr.status
+			= __constant_cpu_to_be16(DM_MAD_STATUS_NO_IOC);
+		return;
+	}
+
+	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->dev_attr.vendor_id);
+	iocp->device_id = cpu_to_be32(sdev->dev_attr.vendor_part_id);
+	iocp->device_version = cpu_to_be16(sdev->dev_attr.hw_ver);
+	iocp->subsys_vendor_id = cpu_to_be32(sdev->dev_attr.vendor_id);
+	iocp->subsys_device_id = 0x0;
+	iocp->io_class = __constant_cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
+	iocp->io_subclass = __constant_cpu_to_be16(SRP_IO_SUBCLASS);
+	iocp->protocol = __constant_cpu_to_be16(SRP_PROTOCOL);
+	iocp->protocol_version = __constant_cpu_to_be16(SRP_PROTOCOL_VERSION);
+	iocp->send_queue_depth = cpu_to_be16(sdev->srq_size);
+	iocp->rdma_read_depth = 4;
+	iocp->send_size = cpu_to_be32(srp_max_req_size);
+	iocp->rdma_size = cpu_to_be32(min(max(srp_max_rdma_size, 256U),
+					  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.
+ *
+ * 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
+			= __constant_cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
+		return;
+	}
+
+	if (slot > 2 || lo > hi || hi > 1) {
+		mad->mad_hdr.status
+			= __constant_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:      source 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->sdev, 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 =
+		    __constant_cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
+		break;
+	}
+}
+
+/**
+ * srpt_mad_send_handler() - Post MAD-send callback function.
+ */
+static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
+				  struct ib_mad_send_wc *mad_wc)
+{
+	ib_destroy_ah(mad_wc->send_buf->ah);
+	ib_free_send_mad(mad_wc->send_buf);
+}
+
+/**
+ * srpt_mad_recv_handler() - MAD reception callback function.
+ */
+static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
+				  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);
+	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 =
+		    __constant_cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
+		break;
+	default:
+		dm_mad->mad_hdr.status =
+		    __constant_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:
+	ib_destroy_ah(ah);
+err:
+	ib_free_recv_mad(mad_wc);
+}
+
+/**
+ * srpt_refresh_port() - Configure a 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_reg_req reg_req;
+	struct ib_port_modify port_modify;
+	struct ib_port_attr port_attr;
+	int ret;
+
+	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)
+		goto err_mod_port;
+
+	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
+	if (ret)
+		goto err_query_port;
+
+	sport->sm_lid = port_attr.sm_lid;
+	sport->lid = port_attr.lid;
+
+	ret = ib_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
+	if (ret)
+		goto err_query_port;
+
+	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);
+
+		sport->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);
+		if (IS_ERR(sport->mad_agent)) {
+			ret = PTR_ERR(sport->mad_agent);
+			sport->mad_agent = NULL;
+			goto err_query_port;
+		}
+	}
+
+	return 0;
+
+err_query_port:
+
+	port_modify.set_port_cap_mask = 0;
+	port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
+	ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
+
+err_mod_port:
+
+	return ret;
+}
+
+/**
+ * srpt_unregister_mad_agent() - Unregister MAD callback functions.
+ *
+ * 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)
+{
+	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 <= sdev->device->phys_port_cnt; i++) {
+		sport = &sdev->port[i - 1];
+		WARN_ON(sport->port != i);
+		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
+			printk(KERN_ERR "disabling MAD processing failed.\n");
+		if (sport->mad_agent) {
+			ib_unregister_mad_agent(sport->mad_agent);
+			sport->mad_agent = NULL;
+		}
+	}
+}
+
+/**
+ * srpt_alloc_ioctx() - Allocate an SRPT I/O context structure.
+ */
+static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
+					   int ioctx_size, int dma_size,
+					   enum dma_data_direction dir)
+{
+	struct srpt_ioctx *ioctx;
+
+	ioctx = kmalloc(ioctx_size, GFP_KERNEL);
+	if (!ioctx)
+		goto err;
+
+	ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
+	if (!ioctx->buf)
+		goto err_free_ioctx;
+
+	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
+	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
+		goto err_free_buf;
+
+	return ioctx;
+
+err_free_buf:
+	kfree(ioctx->buf);
+err_free_ioctx:
+	kfree(ioctx);
+err:
+	return NULL;
+}
+
+/**
+ * srpt_free_ioctx() - Free an SRPT I/O context structure.
+ */
+static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
+			    int dma_size, enum dma_data_direction dir)
+{
+	if (!ioctx)
+		return;
+
+	ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
+	kfree(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.
+ * @dma_size:   DMA buffer size.
+ * @dir:        DMA data direction.
+ */
+static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
+				int ring_size, int ioctx_size,
+				int dma_size, 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));
+	WARN_ON(dma_size != srp_max_req_size && dma_size != srp_max_rsp_size);
+
+	ring = kmalloc(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, dma_size, dir);
+		if (!ring[i])
+			goto err;
+		ring[i]->index = i;
+	}
+	goto out;
+
+err:
+	while (--i >= 0)
+		srpt_free_ioctx(sdev, ring[i], dma_size, dir);
+	kfree(ring);
+out:
+	return ring;
+}
+
+/**
+ * srpt_free_ioctx_ring() - Free the ring of SRPT I/O context structures.
+ */
+static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
+				 struct srpt_device *sdev, int ring_size,
+				 int dma_size, enum dma_data_direction dir)
+{
+	int i;
+
+	WARN_ON(dma_size != srp_max_req_size && dma_size != srp_max_rsp_size);
+
+	for (i = 0; i < ring_size; ++i)
+		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
+	kfree(ioctx_ring);
+}
+
+/**
+ * srpt_get_cmd_state() - Get the state of a SCSI command.
+ */
+static enum srpt_command_state srpt_get_cmd_state(struct srpt_send_ioctx *ioctx)
+{
+	enum srpt_command_state state;
+	unsigned long flags;
+
+	BUG_ON(!ioctx);
+
+	spin_lock_irqsave(&ioctx->spinlock, flags);
+	state = ioctx->state;
+	spin_unlock_irqrestore(&ioctx->spinlock, flags);
+	return state;
+}
+
+/**
+ * srpt_set_cmd_state() - Set the state of a SCSI command.
+ *
+ * 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;
+	unsigned long flags;
+
+	BUG_ON(!ioctx);
+
+	spin_lock_irqsave(&ioctx->spinlock, flags);
+	previous = ioctx->state;
+	if (previous != SRPT_STATE_DONE)
+		ioctx->state = new;
+	spin_unlock_irqrestore(&ioctx->spinlock, flags);
+
+	return previous;
+}
+
+/**
+ * srpt_test_and_set_cmd_state() - Test and set the state of a command.
+ *
+ * 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;
+	unsigned long flags;
+
+	WARN_ON(!ioctx);
+	WARN_ON(old == SRPT_STATE_DONE);
+	WARN_ON(new == SRPT_STATE_NEW);
+
+	spin_lock_irqsave(&ioctx->spinlock, flags);
+	previous = ioctx->state;
+	if (previous == old)
+		ioctx->state = new;
+	spin_unlock_irqrestore(&ioctx->spinlock, flags);
+	return previous == old;
+}
+
+/**
+ * srpt_post_recv() - Post an IB receive request.
+ */
+static int srpt_post_recv(struct srpt_device *sdev,
+			  struct srpt_recv_ioctx *ioctx)
+{
+	struct ib_sge list;
+	struct ib_recv_wr wr, *bad_wr;
+
+	BUG_ON(!sdev);
+	wr.wr_id = encode_wr_id(IB_WC_RECV, ioctx->ioctx.index);
+
+	list.addr = ioctx->ioctx.dma;
+	list.length = srp_max_req_size;
+	list.lkey = sdev->mr->lkey;
+
+	wr.next = NULL;
+	wr.sg_list = &list;
+	wr.num_sge = 1;
+
+	return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
+}
+
+/**
+ * srpt_post_send() - Post an IB send request.
+ *
+ * Returns zero upon success and a non-zero value upon failure.
+ */
+static int srpt_post_send(struct srpt_rdma_ch *ch,
+			  struct srpt_send_ioctx *ioctx, int len)
+{
+	struct ib_sge list;
+	struct ib_send_wr wr, *bad_wr;
+	struct srpt_device *sdev = ch->sport->sdev;
+	int ret;
+
+	atomic_inc(&ch->req_lim);
+
+	ret = -ENOMEM;
+	if (unlikely(atomic_dec_return(&ch->sq_wr_avail) < 0)) {
+		printk(KERN_WARNING "IB send queue full (needed 1)\n");
+		goto out;
+	}
+
+	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, len,
+				      DMA_TO_DEVICE);
+
+	list.addr = ioctx->ioctx.dma;
+	list.length = len;
+	list.lkey = sdev->mr->lkey;
+
+	wr.next = NULL;
+	wr.wr_id = encode_wr_id(IB_WC_SEND, ioctx->ioctx.index);
+	wr.sg_list = &list;
+	wr.num_sge = 1;
+	wr.opcode = IB_WR_SEND;
+	wr.send_flags = IB_SEND_SIGNALED;
+
+	ret = ib_post_send(ch->qp, &wr, &bad_wr);
+
+out:
+	if (ret < 0) {
+		atomic_inc(&ch->sq_wr_avail);
+		atomic_dec(&ch->req_lim);
+	}
+	return ret;
+}
+
+/**
+ * srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request.
+ * @ioctx: Pointer to the I/O context associated with the request.
+ * @srp_cmd: Pointer to the SRP_CMD request data.
+ * @dir: Pointer to the variable to which the transfer direction will be
+ *   written.
+ * @data_len: Pointer to the variable to which the total data length of all
+ *   descriptors in the SRP_CMD request will be written.
+ *
+ * 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_send_ioctx *ioctx,
+			     struct srp_cmd *srp_cmd,
+			     enum dma_data_direction *dir, u64 *data_len)
+{
+	struct srp_indirect_buf *idb;
+	struct srp_direct_buf *db;
+	unsigned add_cdb_offset;
+	int ret;
+
+	/*
+	 * 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));
+
+	BUG_ON(!dir);
+	BUG_ON(!data_len);
+
+	ret = 0;
+	*data_len = 0;
+
+	/*
+	 * 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.
+	 */
+	*dir = DMA_NONE;
+	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;
+
+	/*
+	 * 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".
+	 */
+	add_cdb_offset = srp_cmd->add_cdb_len & ~3;
+	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
+	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
+		ioctx->n_rbuf = 1;
+		ioctx->rbufs = &ioctx->single_rbuf;
+
+		db = (struct srp_direct_buf *)(srp_cmd->add_data
+					       + add_cdb_offset);
+		memcpy(ioctx->rbufs, db, sizeof *db);
+		*data_len = be32_to_cpu(db->len);
+	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
+		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
+		idb = (struct srp_indirect_buf *)(srp_cmd->add_data
+						  + add_cdb_offset);
+
+		ioctx->n_rbuf = be32_to_cpu(idb->table_desc.len) / sizeof *db;
+
+		if (ioctx->n_rbuf >
+		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
+			printk(KERN_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(*db));
+			ioctx->n_rbuf = 0;
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (ioctx->n_rbuf == 1)
+			ioctx->rbufs = &ioctx->single_rbuf;
+		else {
+			ioctx->rbufs =
+				kmalloc(ioctx->n_rbuf * sizeof *db, GFP_ATOMIC);
+			if (!ioctx->rbufs) {
+				ioctx->n_rbuf = 0;
+				ret = -ENOMEM;
+				goto out;
+			}
+		}
+
+		db = idb->desc_list;
+		memcpy(ioctx->rbufs, db, ioctx->n_rbuf * sizeof *db);
+		*data_len = be32_to_cpu(idb->len);
+	}
+out:
+	return ret;
+}
+
+/**
+ * srpt_init_ch_qp() - Initialize queue pair attributes.
+ *
+ * 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;
+
+	attr = kzalloc(sizeof *attr, GFP_KERNEL);
+	if (!attr)
+		return -ENOMEM;
+
+	attr->qp_state = IB_QPS_INIT;
+	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ |
+	    IB_ACCESS_REMOTE_WRITE;
+	attr->port_num = ch->sport->port;
+	attr->pkey_index = 0;
+
+	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;
+
+	qp_attr.qp_state = IB_QPS_RTR;
+	ret = ib_cm_init_qp_attr(ch->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->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'.
+ */
+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_unmap_sg_to_ib_sge() - Unmap an IB SGE list.
+ */
+static void srpt_unmap_sg_to_ib_sge(struct srpt_rdma_ch *ch,
+				    struct srpt_send_ioctx *ioctx)
+{
+	struct scatterlist *sg;
+	enum dma_data_direction dir;
+
+	BUG_ON(!ch);
+	BUG_ON(!ioctx);
+	BUG_ON(ioctx->n_rdma && !ioctx->rdma_ius);
+
+	while (ioctx->n_rdma)
+		kfree(ioctx->rdma_ius[--ioctx->n_rdma].sge);
+
+	kfree(ioctx->rdma_ius);
+	ioctx->rdma_ius = NULL;
+
+	if (ioctx->mapped_sg_count) {
+		sg = ioctx->sg;
+		WARN_ON(!sg);
+		dir = ioctx->cmd.data_direction;
+		BUG_ON(dir == DMA_NONE);
+		ib_dma_unmap_sg(ch->sport->sdev->device, sg, ioctx->sg_cnt,
+				opposite_dma_dir(dir));
+		ioctx->mapped_sg_count = 0;
+	}
+}
+
+/**
+ * srpt_map_sg_to_ib_sge() - Map an SG list to an IB SGE list.
+ */
+static int srpt_map_sg_to_ib_sge(struct srpt_rdma_ch *ch,
+				 struct srpt_send_ioctx *ioctx)
+{
+	struct se_cmd *cmd;
+	struct se_transport_task *task;
+	struct scatterlist *sg, *sg_orig;
+	int sg_cnt;
+	enum dma_data_direction dir;
+	struct rdma_iu *riu;
+	struct srp_direct_buf *db;
+	dma_addr_t dma_addr;
+	struct ib_sge *sge;
+	u64 raddr;
+	u32 rsize;
+	u32 tsize;
+	u32 dma_len;
+	int count, nrdma;
+	int i, j, k;
+
+	BUG_ON(!ch);
+	BUG_ON(!ioctx);
+	cmd = &ioctx->cmd;
+	dir = cmd->data_direction;
+	BUG_ON(dir == DMA_NONE);
+	task = cmd->t_task;
+	if (cmd->se_cmd_flags & (SCF_SCSI_DATA_SG_IO_CDB
+				 | SCF_SCSI_CONTROL_SG_IO_CDB)) {
+		transport_do_task_sg_chain(cmd);
+		sg = sg_orig = task->t_tasks_sg_chained;
+		sg_cnt = task->t_tasks_sg_chained_no;
+	} else if (cmd->se_cmd_flags & SCF_SCSI_CONTROL_NONSG_IO_CDB) {
+		/* Use task->t_tasks_sg_bounce for control CDBs. */
+		sg_init_table(&task->t_tasks_sg_bounce, 1);
+		sg_set_buf(&task->t_tasks_sg_bounce, task->t_task_buf,
+			   cmd->data_length);
+		sg = sg_orig = &task->t_tasks_sg_bounce;
+		sg_cnt = 1;
+	} else {
+		pr_debug("?? sg == NULL\n");
+		ioctx->mapped_sg_count = 0;
+		return 0;
+	}
+	ioctx->sg = sg;
+	ioctx->sg_cnt = sg_cnt;
+	count = ib_dma_map_sg(ch->sport->sdev->device, sg, sg_cnt,
+			      opposite_dma_dir(dir));
+	if (unlikely(!count))
+		return -EBUSY;
+
+	ioctx->mapped_sg_count = count;
+
+	if (ioctx->rdma_ius && ioctx->n_rdma_ius)
+		nrdma = ioctx->n_rdma_ius;
+	else {
+		nrdma = count / SRPT_DEF_SG_PER_WQE + ioctx->n_rbuf;
+
+		ioctx->rdma_ius = kzalloc(nrdma * sizeof *riu, GFP_KERNEL);
+		if (!ioctx->rdma_ius)
+			goto free_mem;
+
+		ioctx->n_rdma_ius = nrdma;
+	}
+
+	db = ioctx->rbufs;
+	tsize = cmd->data_length;
+	dma_len = sg_dma_len(&sg[0]);
+	riu = ioctx->rdma_ius;
+
+	/*
+	 * For each remote desc - calculate the #ib_sge.
+	 * If #ib_sge < SRPT_DEF_SG_PER_WQE per rdma operation then
+	 *      each remote desc rdma_iu is required a rdma wr;
+	 * else
+	 *      we need to allocate extra rdma_iu to carry extra #ib_sge in
+	 *      another rdma wr
+	 */
+	for (i = 0, j = 0;
+	     j < count && i < ioctx->n_rbuf && tsize > 0; ++i, ++riu, ++db) {
+		rsize = be32_to_cpu(db->len);
+		raddr = be64_to_cpu(db->va);
+		riu->raddr = raddr;
+		riu->rkey = be32_to_cpu(db->key);
+		riu->sge_cnt = 0;
+
+		/* calculate how many sge required for this remote_buf */
+		while (rsize > 0 && tsize > 0) {
+
+			if (rsize >= dma_len) {
+				tsize -= dma_len;
+				rsize -= dma_len;
+				raddr += dma_len;
+
+				if (tsize > 0) {
+					++j;
+					if (j < count) {
+						sg = sg_next(sg);
+						dma_len = sg_dma_len(sg);
+					}
+				}
+			} else {
+				tsize -= rsize;
+				dma_len -= rsize;
+				rsize = 0;
+			}
+
+			++riu->sge_cnt;
+
+			if (rsize > 0 && riu->sge_cnt == SRPT_DEF_SG_PER_WQE) {
+				++ioctx->n_rdma;
+				riu->sge =
+				    kmalloc(riu->sge_cnt * sizeof *riu->sge,
+					    GFP_KERNEL);
+				if (!riu->sge)
+					goto free_mem;
+
+				++riu;
+				riu->sge_cnt = 0;
+				riu->raddr = raddr;
+				riu->rkey = be32_to_cpu(db->key);
+			}
+		}
+
+		++ioctx->n_rdma;
+		riu->sge = kmalloc(riu->sge_cnt * sizeof *riu->sge,
+				   GFP_KERNEL);
+		if (!riu->sge)
+			goto free_mem;
+	}
+
+	db = ioctx->rbufs;
+	tsize = cmd->data_length;
+	riu = ioctx->rdma_ius;
+	sg = sg_orig;
+	dma_len = sg_dma_len(&sg[0]);
+	dma_addr = sg_dma_address(&sg[0]);
+
+	/* this second loop is really mapped sg_addres to rdma_iu->ib_sge */
+	for (i = 0, j = 0;
+	     j < count && i < ioctx->n_rbuf && tsize > 0; ++i, ++riu, ++db) {
+		rsize = be32_to_cpu(db->len);
+		sge = riu->sge;
+		k = 0;
+
+		while (rsize > 0 && tsize > 0) {
+			sge->addr = dma_addr;
+			sge->lkey = ch->sport->sdev->mr->lkey;
+
+			if (rsize >= dma_len) {
+				sge->length =
+					(tsize < dma_len) ? tsize : dma_len;
+				tsize -= dma_len;
+				rsize -= dma_len;
+
+				if (tsize > 0) {
+					++j;
+					if (j < count) {
+						sg = sg_next(sg);
+						dma_len = sg_dma_len(sg);
+						dma_addr = sg_dma_address(sg);
+					}
+				}
+			} else {
+				sge->length = (tsize < rsize) ? tsize : rsize;
+				tsize -= rsize;
+				dma_len -= rsize;
+				dma_addr += rsize;
+				rsize = 0;
+			}
+
+			++k;
+			if (k == riu->sge_cnt && rsize > 0) {
+				++riu;
+				sge = riu->sge;
+				k = 0;
+			} else if (rsize > 0)
+				++sge;
+		}
+	}
+
+	return 0;
+
+free_mem:
+	srpt_unmap_sg_to_ib_sge(ch, ioctx);
+
+	return -ENOMEM;
+}
+
+/**
+ * srpt_get_send_ioctx() - Obtain an I/O context for sending to the initiator.
+ */
+static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
+{
+	struct srpt_send_ioctx *ioctx;
+	unsigned long flags;
+
+	BUG_ON(!ch);
+
+	ioctx = NULL;
+	spin_lock_irqsave(&ch->spinlock, flags);
+	if (!list_empty(&ch->free_list)) {
+		ioctx = list_first_entry(&ch->free_list,
+					 struct srpt_send_ioctx, free_list);
+		list_del(&ioctx->free_list);
+	}
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+
+	if (!ioctx)
+		return ioctx;
+
+	BUG_ON(ioctx->ch != ch);
+	kref_init(&ioctx->kref);
+	spin_lock_init(&ioctx->spinlock);
+	ioctx->state = SRPT_STATE_NEW;
+	ioctx->n_rbuf = 0;
+	ioctx->rbufs = NULL;
+	ioctx->n_rdma = 0;
+	ioctx->n_rdma_ius = 0;
+	ioctx->rdma_ius = NULL;
+	ioctx->mapped_sg_count = 0;
+	init_completion(&ioctx->tx_done);
+	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));
+
+	return ioctx;
+}
+
+/**
+ * srpt_put_send_ioctx() - Free up resources.
+ */
+static void srpt_put_send_ioctx(struct srpt_send_ioctx *ioctx)
+{
+	struct srpt_rdma_ch *ch;
+	unsigned long flags;
+
+	BUG_ON(!ioctx);
+	ch = ioctx->ch;
+	BUG_ON(!ch);
+
+	WARN_ON(srpt_get_cmd_state(ioctx) != SRPT_STATE_DONE);
+
+	srpt_unmap_sg_to_ib_sge(ioctx->ch, ioctx);
+	transport_generic_free_cmd(&ioctx->cmd, 0, 1, 0);
+
+	if (ioctx->n_rbuf > 1) {
+		kfree(ioctx->rbufs);
+		ioctx->rbufs = NULL;
+		ioctx->n_rbuf = 0;
+	}
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	list_add(&ioctx->free_list, &ch->free_list);
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+}
+
+static void srpt_put_send_ioctx_kref(struct kref *kref)
+{
+	srpt_put_send_ioctx(container_of(kref, struct srpt_send_ioctx, kref));
+}
+
+/**
+ * srpt_abort_cmd() - Abort a SCSI command.
+ * @ioctx:   I/O context associated with the SCSI command.
+ * @context: Preferred execution context.
+ */
+static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
+{
+	enum srpt_command_state state;
+	unsigned long flags;
+
+	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. Changing
+	 * the state of the command from SRPT_STATE_NEED_DATA to
+	 * SRPT_STATE_DATA_IN ensures that srpt_xmit_response() will call this
+	 * function a second time.
+	 */
+
+	spin_lock_irqsave(&ioctx->spinlock, flags);
+	state = ioctx->state;
+	switch (state) {
+	case SRPT_STATE_NEED_DATA:
+		ioctx->state = SRPT_STATE_DATA_IN;
+		break;
+	case SRPT_STATE_DATA_IN:
+	case SRPT_STATE_CMD_RSP_SENT:
+	case SRPT_STATE_MGMT_RSP_SENT:
+		ioctx->state = SRPT_STATE_DONE;
+		break;
+	default:
+		break;
+	}
+	spin_unlock_irqrestore(&ioctx->spinlock, flags);
+
+	if (state == SRPT_STATE_DONE)
+		goto out;
+
+	pr_debug("Aborting cmd with state %d and tag %lld\n", state,
+		 ioctx->tag);
+
+	switch (state) {
+	case SRPT_STATE_NEW:
+	case SRPT_STATE_DATA_IN:
+	case SRPT_STATE_MGMT:
+		/*
+		 * Do nothing - defer abort processing until
+		 * srpt_queue_response() is invoked.
+		 */
+		WARN_ON(!transport_check_aborted_status(&ioctx->cmd, false));
+		break;
+	case SRPT_STATE_NEED_DATA:
+		/* DMA_TO_DEVICE (write) - RDMA read error. */
+		atomic_set(&ioctx->cmd.t_task->transport_lun_stop, 1);
+		transport_generic_handle_data(&ioctx->cmd);
+		break;
+	case SRPT_STATE_CMD_RSP_SENT:
+		/*
+		 * SRP_RSP sending failed or the SRP_RSP send completion has
+		 * not been received in time.
+		 */
+		srpt_unmap_sg_to_ib_sge(ioctx->ch, ioctx);
+		atomic_set(&ioctx->cmd.t_task->transport_lun_stop, 1);
+		kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
+		break;
+	case SRPT_STATE_MGMT_RSP_SENT:
+		srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
+		kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
+		break;
+	default:
+		WARN_ON("ERROR: unexpected command state");
+		break;
+	}
+
+out:
+	return state;
+}
+
+/**
+ * srpt_handle_send_err_comp() - Process an IB_WC_SEND error completion.
+ */
+static void srpt_handle_send_err_comp(struct srpt_rdma_ch *ch, u64 wr_id)
+{
+	struct srpt_send_ioctx *ioctx;
+	enum srpt_command_state state;
+	struct se_cmd *cmd;
+	u32 index;
+
+	atomic_inc(&ch->sq_wr_avail);
+
+	index = idx_from_wr_id(wr_id);
+	ioctx = ch->ioctx_ring[index];
+	state = srpt_get_cmd_state(ioctx);
+	cmd = &ioctx->cmd;
+
+	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
+		&& state != SRPT_STATE_MGMT_RSP_SENT
+		&& state != SRPT_STATE_NEED_DATA
+		&& state != SRPT_STATE_DONE);
+
+	/* If SRP_RSP sending failed, undo the ch->req_lim change. */
+	if (state == SRPT_STATE_CMD_RSP_SENT
+	    || state == SRPT_STATE_MGMT_RSP_SENT)
+		atomic_dec(&ch->req_lim);
+
+	srpt_abort_cmd(ioctx);
+}
+
+/**
+ * srpt_handle_send_comp() - Process an IB send completion notification.
+ */
+static void srpt_handle_send_comp(struct srpt_rdma_ch *ch,
+				  struct srpt_send_ioctx *ioctx)
+{
+	enum srpt_command_state state;
+
+	atomic_inc(&ch->sq_wr_avail);
+
+	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
+
+	if (WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
+		    && state != SRPT_STATE_MGMT_RSP_SENT
+		    && state != SRPT_STATE_DONE))
+		pr_debug("state = %d\n", state);
+
+	if (state != SRPT_STATE_DONE)
+		kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
+	else
+		printk(KERN_ERR "IB completion has been received too late for"
+		       " wr_id = %u.\n", ioctx->ioctx.index);
+}
+
+/**
+ * srpt_handle_rdma_comp() - Process an IB RDMA completion notification.
+ *
+ * Note: transport_generic_handle_data() is asynchronous so unmapping the
+ * data that has been transferred via IB RDMA must be postponed until the
+ * check_stop_free() callback.
+ */
+static void srpt_handle_rdma_comp(struct srpt_rdma_ch *ch,
+				  struct srpt_send_ioctx *ioctx)
+{
+	WARN_ON(ioctx->n_rdma <= 0);
+	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
+
+	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
+					SRPT_STATE_DATA_IN))
+		transport_generic_handle_data(&ioctx->cmd);
+	else
+		printk(KERN_ERR "%s[%d]: wrong state = %d\n", __func__,
+		       __LINE__, srpt_get_cmd_state(ioctx));
+}
+
+/**
+ * srpt_handle_rdma_err_comp() - Process an IB RDMA error completion.
+ */
+static void srpt_handle_rdma_err_comp(struct srpt_rdma_ch *ch,
+				      struct srpt_send_ioctx *ioctx,
+				      u8 opcode)
+{
+	struct se_cmd *cmd;
+	enum srpt_command_state state;
+
+	cmd = &ioctx->cmd;
+	state = srpt_get_cmd_state(ioctx);
+	switch (opcode) {
+	case IB_WC_RDMA_READ:
+		if (ioctx->n_rdma <= 0) {
+			printk(KERN_ERR "Received invalid RDMA read"
+			       " error completion with idx %d\n",
+			       ioctx->ioctx.index);
+			break;
+		}
+		atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
+		if (state == SRPT_STATE_NEED_DATA)
+			srpt_abort_cmd(ioctx);
+		else
+			printk(KERN_ERR "%s[%d]: wrong state = %d\n",
+			       __func__, __LINE__, state);
+		break;
+	case IB_WC_RDMA_WRITE:
+		atomic_set(&ioctx->cmd.t_task->transport_lun_stop, 1);
+		break;
+	default:
+		printk(KERN_ERR "%s[%d]: opcode = %u\n", __func__,
+		       __LINE__, opcode);
+		break;
+	}
+}
+
+/**
+ * srpt_build_cmd_rsp() - Build an 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 srp_rsp *srp_rsp;
+	const u8 *sense_data;
+	int sense_data_len, max_sense_len;
+
+	/*
+	 * 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 =
+		__constant_cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
+	srp_rsp->tag = tag;
+	srp_rsp->status = status;
+
+	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) {
+			printk(KERN_WARNING "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 + 1, 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 = (rsp_code == SRP_TSK_MGMT_SUCCESS) ? 0 : 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 = __constant_cpu_to_be32(1
+				    + atomic_xchg(&ch->req_lim_delta, 0));
+	srp_rsp->tag = tag;
+
+	if (rsp_code != SRP_TSK_MGMT_SUCCESS) {
+		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;
+}
+
+#define NO_SUCH_LUN ((uint64_t)-1LL)
+
+/*
+ * SCSI LUN addressing method. See also SAM-2 and the section about
+ * eight byte LUNs.
+ */
+enum scsi_lun_addr_method {
+	SCSI_LUN_ADDR_METHOD_PERIPHERAL   = 0,
+	SCSI_LUN_ADDR_METHOD_FLAT         = 1,
+	SCSI_LUN_ADDR_METHOD_LUN          = 2,
+	SCSI_LUN_ADDR_METHOD_EXTENDED_LUN = 3,
+};
+
+/*
+ * srpt_unpack_lun() - Convert from network LUN to linear LUN.
+ *
+ * Convert an 2-byte, 4-byte, 6-byte or 8-byte LUN structure in network byte
+ * order (big endian) to a linear LUN. Supports three LUN addressing methods:
+ * peripheral, flat and logical unit. See also SAM-2, section 4.9.4 (page 40).
+ */
+static uint64_t srpt_unpack_lun(const uint8_t *lun, int len)
+{
+	uint64_t res = NO_SUCH_LUN;
+	int addressing_method;
+
+	if (unlikely(len < 2)) {
+		printk(KERN_ERR "Illegal LUN length %d, expected 2 bytes or "
+		       "more", len);
+		goto out;
+	}
+
+	switch (len) {
+	case 8:
+		if ((*((__be64 *)lun) &
+		     __constant_cpu_to_be64(0x0000FFFFFFFFFFFFLL)) != 0)
+			goto out_err;
+		break;
+	case 4:
+		if (*((__be16 *)&lun[2]) != 0)
+			goto out_err;
+		break;
+	case 6:
+		if (*((__be32 *)&lun[2]) != 0)
+			goto out_err;
+		break;
+	case 2:
+		break;
+	default:
+		goto out_err;
+	}
+
+	addressing_method = (*lun) >> 6; /* highest two bits of byte 0 */
+	switch (addressing_method) {
+	case SCSI_LUN_ADDR_METHOD_PERIPHERAL:
+	case SCSI_LUN_ADDR_METHOD_FLAT:
+	case SCSI_LUN_ADDR_METHOD_LUN:
+		res = *(lun + 1) | (((*lun) & 0x3f) << 8);
+		break;
+
+	case SCSI_LUN_ADDR_METHOD_EXTENDED_LUN:
+	default:
+		printk(KERN_ERR "Unimplemented LUN addressing method %u",
+		       addressing_method);
+		break;
+	}
+
+out:
+	return res;
+
+out_err:
+	printk(KERN_ERR "Support for multi-level LUNs has not yet been"
+	       " implemented");
+	goto out;
+}
+
+static void srpt_check_stop_free(struct se_cmd *cmd)
+{
+	struct srpt_send_ioctx *ioctx;
+
+	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
+	kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
+}
+
+/**
+ * srpt_handle_cmd() - Process SRP_CMD.
+ */
+static int 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;
+	uint64_t unpacked_lun;
+	u64 data_len;
+	enum dma_data_direction dir;
+	int ret;
+
+	BUG_ON(!send_ioctx);
+
+	srp_cmd = recv_ioctx->ioctx.buf;
+	kref_get(&send_ioctx->kref);
+	cmd = &send_ioctx->cmd;
+	send_ioctx->tag = srp_cmd->tag;
+
+	switch (srp_cmd->task_attr) {
+	case SRP_CMD_SIMPLE_Q:
+		cmd->sam_task_attr = TASK_ATTR_SIMPLE;
+		break;
+	case SRP_CMD_ORDERED_Q:
+	default:
+		cmd->sam_task_attr = TASK_ATTR_ORDERED;
+		break;
+	case SRP_CMD_HEAD_OF_Q:
+		cmd->sam_task_attr = TASK_ATTR_HOQ;
+		break;
+	case SRP_CMD_ACA:
+		cmd->sam_task_attr = TASK_ATTR_ACA;
+		break;
+	}
+
+	ret = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &data_len);
+	if (ret) {
+		printk(KERN_ERR "0x%llx: parsing SRP descriptor table failed.\n",
+		       srp_cmd->tag);
+		cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+		cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+		goto send_sense;
+	}
+
+	cmd->data_length = data_len;
+	cmd->data_direction = dir;
+	unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_cmd->lun,
+				       sizeof(srp_cmd->lun));
+	if (transport_get_lun_for_cmd(cmd, NULL, unpacked_lun) < 0)
+		goto send_sense;
+	ret = transport_generic_allocate_tasks(cmd, srp_cmd->cdb);
+	if (cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
+		srpt_queue_status(cmd);
+	else if (cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION)
+		goto send_sense;
+	else
+		WARN_ON_ONCE(ret);
+
+	transport_generic_handle_cdb(cmd);
+	return 0;
+
+send_sense:
+	transport_send_check_condition_and_sense(cmd, cmd->scsi_sense_reason,
+						 0);
+	return -1;
+}
+
+/**
+ * srpt_rx_mgmt_fn_tag() - Process a task management function by tag.
+ * @ch: RDMA channel of the task management request.
+ * @fn: Task management function to perform.
+ * @req_tag: Tag of the SRP task management request.
+ * @mgmt_ioctx: I/O context of the task management request.
+ *
+ * Returns zero if the target core will process the task management
+ * request asynchronously.
+ *
+ * Note: It is assumed that the initiator serializes tag-based task management
+ * requests.
+ */
+static int srpt_rx_mgmt_fn_tag(struct srpt_send_ioctx *ioctx, u64 tag)
+{
+	struct srpt_device *sdev;
+	struct srpt_rdma_ch *ch;
+	struct srpt_send_ioctx *target;
+	int ret, i;
+
+	ret = -EINVAL;
+	ch = ioctx->ch;
+	BUG_ON(!ch);
+	BUG_ON(!ch->sport);
+	sdev = ch->sport->sdev;
+	BUG_ON(!sdev);
+	spin_lock_irq(&sdev->spinlock);
+	for (i = 0; i < ch->rq_size; ++i) {
+		target = ch->ioctx_ring[i];
+		if (target->cmd.se_lun == ioctx->cmd.se_lun &&
+		    target->tag == tag &&
+		    srpt_get_cmd_state(target) != SRPT_STATE_DONE) {
+			ret = 0;
+			/* now let the target core abort &target->cmd; */
+			break;
+		}
+	}
+	spin_unlock_irq(&sdev->spinlock);
+	return ret;
+}
+
+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 an SRP_TSK_MGMT information unit.
+ *
+ * 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;
+	uint64_t unpacked_lun;
+	int tcm_tmr;
+	int res;
+
+	BUG_ON(!send_ioctx);
+
+	srp_tsk = recv_ioctx->ioctx.buf;
+	cmd = &send_ioctx->cmd;
+
+	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
+		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
+		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);
+
+	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
+	send_ioctx->tag = srp_tsk->tag;
+	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
+	if (tcm_tmr < 0) {
+		send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+		send_ioctx->cmd.se_tmr_req->response =
+			TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
+		goto process_tmr;
+	}
+	cmd->se_tmr_req = core_tmr_alloc_req(cmd, NULL, tcm_tmr);
+	if (!cmd->se_tmr_req) {
+		send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
+		goto process_tmr;
+	}
+
+	unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_tsk->lun,
+				       sizeof(srp_tsk->lun));
+	res = transport_get_lun_for_tmr(&send_ioctx->cmd, unpacked_lun);
+	if (res) {
+		pr_debug("rejecting TMR for LUN %lld\n", unpacked_lun);
+		send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+		send_ioctx->cmd.se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
+		goto process_tmr;
+	}
+
+	if (srp_tsk->tsk_mgmt_func == SRP_TSK_ABORT_TASK)
+		srpt_rx_mgmt_fn_tag(send_ioctx, srp_tsk->task_tag);
+
+process_tmr:
+	kref_get(&send_ioctx->kref);
+	if (!(send_ioctx->cmd.se_cmd_flags & SCF_SCSI_CDB_EXCEPTION))
+		transport_generic_handle_tmr(&send_ioctx->cmd);
+	else
+		transport_send_check_condition_and_sense(cmd,
+						cmd->scsi_sense_reason, 0);
+
+}
+
+/**
+ * srpt_handle_new_iu() - Process a newly received information unit.
+ * @ch:    RDMA channel through which the information unit has been received.
+ * @ioctx: SRPT I/O context associated with the information unit.
+ */
+static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
+			       struct srpt_recv_ioctx *recv_ioctx,
+			       struct srpt_send_ioctx *send_ioctx)
+{
+	struct srp_cmd *srp_cmd;
+	enum rdma_ch_state ch_state;
+
+	BUG_ON(!ch);
+	BUG_ON(!recv_ioctx);
+
+	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
+				   recv_ioctx->ioctx.dma, srp_max_req_size,
+				   DMA_FROM_DEVICE);
+
+	ch_state = srpt_get_ch_state(ch);
+	if (unlikely(ch_state == CH_CONNECTING)) {
+		list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
+		goto out;
+	}
+
+	if (unlikely(ch_state != CH_LIVE))
+		goto out;
+
+	srp_cmd = recv_ioctx->ioctx.buf;
+	if (srp_cmd->opcode == SRP_CMD || srp_cmd->opcode == SRP_TSK_MGMT) {
+		if (!send_ioctx)
+			send_ioctx = srpt_get_send_ioctx(ch);
+		if (unlikely(!send_ioctx)) {
+			list_add_tail(&recv_ioctx->wait_list,
+				      &ch->cmd_wait_list);
+			goto out;
+		}
+	}
+
+	transport_init_se_cmd(&send_ioctx->cmd, &srpt_target->tf_ops, ch->sess,
+			      0, DMA_NONE, TASK_ATTR_SIMPLE,
+			      send_ioctx->sense_data);
+
+	switch (srp_cmd->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:
+		printk(KERN_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:
+		printk(KERN_ERR "Received SRP_RSP\n");
+		break;
+	default:
+		printk(KERN_ERR "received IU with unknown opcode 0x%x\n",
+		       srp_cmd->opcode);
+		break;
+	}
+
+	srpt_post_recv(ch->sport->sdev, recv_ioctx);
+out:
+	return;
+}
+
+static void srpt_process_rcv_completion(struct ib_cq *cq,
+					struct srpt_rdma_ch *ch,
+					struct ib_wc *wc)
+{
+	struct srpt_device *sdev = ch->sport->sdev;
+	struct srpt_recv_ioctx *ioctx;
+	u32 index;
+
+	index = idx_from_wr_id(wc->wr_id);
+	if (wc->status == IB_WC_SUCCESS) {
+		int req_lim;
+
+		req_lim = atomic_dec_return(&ch->req_lim);
+		if (unlikely(req_lim < 0))
+			printk(KERN_ERR "req_lim = %d < 0\n", req_lim);
+		ioctx = sdev->ioctx_ring[index];
+		srpt_handle_new_iu(ch, ioctx, NULL);
+	} else {
+		printk(KERN_INFO "receiving failed for idx %u with status %d\n",
+		       index, wc->status);
+	}
+}
+
+/**
+ * srpt_process_send_completion() - Process an IB send 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_process_send_completion(struct ib_cq *cq,
+					 struct srpt_rdma_ch *ch,
+					 struct ib_wc *wc)
+{
+	struct srpt_send_ioctx *send_ioctx;
+	uint32_t index;
+	u8 opcode;
+
+	index = idx_from_wr_id(wc->wr_id);
+	opcode = opcode_from_wr_id(wc->wr_id);
+	send_ioctx = ch->ioctx_ring[index];
+	if (wc->status == IB_WC_SUCCESS) {
+		if (opcode == IB_WC_SEND)
+			srpt_handle_send_comp(ch, send_ioctx);
+		else {
+			WARN_ON(wc->opcode != IB_WC_RDMA_READ);
+			srpt_handle_rdma_comp(ch, send_ioctx);
+		}
+	} else {
+		if (opcode == IB_WC_SEND) {
+			printk(KERN_INFO "sending response for idx %u failed"
+			       " with status %d\n", index, wc->status);
+			srpt_handle_send_err_comp(ch, wc->wr_id);
+		} else {
+			printk(KERN_INFO "RDMA %s for idx %u failed with status"
+			       " %d\n", opcode == IB_WC_RDMA_READ ? "read"
+			       : opcode == IB_WC_RDMA_WRITE ? "write"
+			       : "???", index, wc->status);
+			srpt_handle_rdma_err_comp(ch, send_ioctx, opcode);
+		}
+	}
+
+	while (unlikely(opcode == IB_WC_SEND
+			&& !list_empty(&ch->cmd_wait_list)
+			&& srpt_get_ch_state(ch) == CH_LIVE
+			&& (send_ioctx = srpt_get_send_ioctx(ch)) != NULL)) {
+		struct srpt_recv_ioctx *recv_ioctx;
+
+		recv_ioctx = list_first_entry(&ch->cmd_wait_list,
+					      struct srpt_recv_ioctx,
+					      wait_list);
+		list_del(&recv_ioctx->wait_list);
+		srpt_handle_new_iu(ch, recv_ioctx, send_ioctx);
+	}
+}
+
+static void srpt_process_completion(struct ib_cq *cq, struct srpt_rdma_ch *ch)
+{
+	struct ib_wc *const wc = ch->wc;
+	int i, n;
+
+	WARN_ON(cq != ch->cq);
+
+	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
+	while ((n = ib_poll_cq(cq, ARRAY_SIZE(ch->wc), wc)) > 0) {
+		for (i = 0; i < n; i++) {
+			if (opcode_from_wr_id(wc[i].wr_id) & IB_WC_RECV)
+				srpt_process_rcv_completion(cq, ch, &wc[i]);
+			else
+				srpt_process_send_completion(cq, ch, &wc[i]);
+		}
+	}
+}
+
+/**
+ * srpt_completion() - IB completion queue callback function.
+ *
+ * Notes:
+ * - It is guaranteed that a completion handler will never be invoked
+ *   concurrently on two different CPUs for the same completion queue. See also
+ *   Documentation/infiniband/core_locking.txt and the implementation of
+ *   handle_edge_irq() in kernel/irq/chip.c.
+ * - When threaded IRQs are enabled, completion handlers are invoked in thread
+ *   context instead of interrupt context.
+ */
+static void srpt_completion(struct ib_cq *cq, void *ctx)
+{
+	struct srpt_rdma_ch *ch = ctx;
+
+	wake_up_interruptible(&ch->wait_queue);
+}
+
+static int srpt_compl_thread(void *arg)
+{
+	struct srpt_rdma_ch *ch;
+
+	/* Hibernation / freezing of the SRPT kernel thread is not supported. */
+	current->flags |= PF_NOFREEZE;
+
+	ch = arg;
+	BUG_ON(!ch);
+	printk(KERN_INFO "Session %s: kernel thread %s (PID %d) started\n",
+	       ch->sess_name, ch->thread->comm, current->pid);
+	while (!kthread_should_stop()) {
+		wait_event_interruptible(ch->wait_queue,
+			(srpt_process_completion(ch->cq, ch),
+			 kthread_should_stop()));
+	}
+	printk(KERN_INFO "Session %s: kernel thread %s (PID %d) stopped\n",
+	       ch->sess_name, ch->thread->comm, current->pid);
+	return 0;
+}
+
+/**
+ * srpt_create_ch_ib() - Create receive and send completion queues.
+ */
+static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
+{
+	struct ib_qp_init_attr *qp_init;
+	struct srpt_device *sdev = ch->sport->sdev;
+	int ret;
+
+	WARN_ON(ch->rq_size < 1);
+
+	ret = -ENOMEM;
+	qp_init = kzalloc(sizeof *qp_init, GFP_KERNEL);
+	if (!qp_init)
+		goto out;
+
+	ch->cq = ib_create_cq(sdev->device, srpt_completion, NULL, ch,
+			      ch->rq_size + srpt_sq_size, 0);
+	if (IS_ERR(ch->cq)) {
+		ret = PTR_ERR(ch->cq);
+		printk(KERN_ERR "failed to create CQ cqe= %d ret= %d\n",
+		       ch->rq_size + srpt_sq_size, ret);
+		goto out;
+	}
+
+	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->srq = sdev->srq;
+	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
+	qp_init->qp_type = IB_QPT_RC;
+	qp_init->cap.max_send_wr = srpt_sq_size;
+	qp_init->cap.max_send_sge = SRPT_DEF_SG_PER_WQE;
+
+	ch->qp = ib_create_qp(sdev->pd, qp_init);
+	if (IS_ERR(ch->qp)) {
+		ret = PTR_ERR(ch->qp);
+		printk(KERN_ERR "failed to create_qp ret= %d\n", 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 cm_id= %p\n",
+		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
+		 qp_init->cap.max_send_wr, ch->cm_id);
+
+	ret = srpt_init_ch_qp(ch, ch->qp);
+	if (ret)
+		goto err_destroy_qp;
+
+	init_waitqueue_head(&ch->wait_queue);
+
+	pr_debug("creating thread for session %s\n", ch->sess_name);
+
+	ch->thread = kthread_run(srpt_compl_thread, ch, "ib_srpt_compl");
+	if (IS_ERR(ch->thread)) {
+		printk(KERN_ERR "failed to create kernel thread %ld\n",
+		       PTR_ERR(ch->thread));
+		ch->thread = NULL;
+		goto err_destroy_qp;
+	}
+
+out:
+	kfree(qp_init);
+	return ret;
+
+err_destroy_qp:
+	ib_destroy_qp(ch->qp);
+err_destroy_cq:
+	ib_destroy_cq(ch->cq);
+	goto out;
+}
+
+static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
+{
+	if (ch->thread)
+		kthread_stop(ch->thread);
+
+	ib_destroy_qp(ch->qp);
+	ib_destroy_cq(ch->cq);
+}
+
+/**
+ * __srpt_close_ch() - Close an RDMA channel by setting the QP error state.
+ *
+ * Reset the QP and make sure all resources associated with the channel will
+ * be deallocated at an appropriate time.
+ *
+ * Note: The caller must hold ch->sport->sdev->spinlock.
+ */
+static void __srpt_close_ch(struct srpt_rdma_ch *ch)
+{
+	struct srpt_device *sdev;
+	enum rdma_ch_state prev_state;
+	unsigned long flags;
+
+	sdev = ch->sport->sdev;
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	prev_state = ch->state;
+	switch (prev_state) {
+	case CH_CONNECTING:
+	case CH_LIVE:
+		ch->state = CH_DISCONNECTING;
+		break;
+	default:
+		break;
+	}
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+
+	switch (prev_state) {
+	case CH_CONNECTING:
+		ib_send_cm_rej(ch->cm_id, IB_CM_REJ_NO_RESOURCES, NULL, 0,
+			       NULL, 0);
+		/* fall through */
+	case CH_LIVE:
+		if (ib_send_cm_dreq(ch->cm_id, NULL, 0) < 0)
+			printk(KERN_ERR "sending CM DREQ failed.\n");
+		break;
+	case CH_DISCONNECTING:
+		break;
+	case CH_DRAINING:
+	case CH_RELEASING:
+		break;
+	}
+}
+
+/**
+ * srpt_close_ch() - Close an RDMA channel.
+ */
+static void srpt_close_ch(struct srpt_rdma_ch *ch)
+{
+	struct srpt_device *sdev;
+
+	sdev = ch->sport->sdev;
+	spin_lock_irq(&sdev->spinlock);
+	__srpt_close_ch(ch);
+	spin_unlock_irq(&sdev->spinlock);
+}
+
+/**
+ * srpt_drain_channel() - Drain a channel by resetting the IB queue pair.
+ * @cm_id: Pointer to the CM ID of the channel to be drained.
+ *
+ * Note: Must be called from inside srpt_cm_handler to avoid a race between
+ * accessing sdev->spinlock and the call to kfree(sdev) in srpt_remove_one()
+ * (the caller of srpt_cm_handler holds the cm_id spinlock; srpt_remove_one()
+ * waits until all target sessions for the associated IB device have been
+ * unregistered and target session registration involves a call to
+ * ib_destroy_cm_id(), which locks the cm_id spinlock and hence waits until
+ * this function has finished).
+ */
+static void srpt_drain_channel(struct ib_cm_id *cm_id)
+{
+	struct srpt_device *sdev;
+	struct srpt_rdma_ch *ch;
+	int ret;
+	bool do_reset = false;
+
+	WARN_ON_ONCE(irqs_disabled());
+
+	sdev = cm_id->context;
+	BUG_ON(!sdev);
+	spin_lock_irq(&sdev->spinlock);
+	list_for_each_entry(ch, &sdev->rch_list, list) {
+		if (ch->cm_id == cm_id) {
+			do_reset = srpt_test_and_set_ch_state(ch,
+					CH_CONNECTING, CH_DRAINING) ||
+				   srpt_test_and_set_ch_state(ch,
+					CH_LIVE, CH_DRAINING) ||
+				   srpt_test_and_set_ch_state(ch,
+					CH_DISCONNECTING, CH_DRAINING);
+			break;
+		}
+	}
+	spin_unlock_irq(&sdev->spinlock);
+
+	if (do_reset) {
+		ret = srpt_ch_qp_err(ch);
+		if (ret < 0)
+			printk(KERN_ERR "Setting queue pair in error state"
+			       " failed: %d\n", ret);
+	}
+}
+
+/**
+ * srpt_find_channel() - Look up an RDMA channel.
+ * @cm_id: Pointer to the CM ID of the channel to be looked up.
+ *
+ * Return NULL if no matching RDMA channel has been found.
+ */
+static struct srpt_rdma_ch *srpt_find_channel(struct srpt_device *sdev,
+					      struct ib_cm_id *cm_id)
+{
+	struct srpt_rdma_ch *ch;
+	bool found;
+
+	WARN_ON_ONCE(irqs_disabled());
+	BUG_ON(!sdev);
+
+	found = false;
+	spin_lock_irq(&sdev->spinlock);
+	list_for_each_entry(ch, &sdev->rch_list, list) {
+		if (ch->cm_id == cm_id) {
+			found = true;
+			break;
+		}
+	}
+	spin_unlock_irq(&sdev->spinlock);
+
+	return found ? ch : NULL;
+}
+
+/**
+ * srpt_release_channel() - Release channel resources.
+ *
+ * Schedules the actual release because:
+ * - Calling the ib_destroy_cm_id() call from inside an IB CM callback would
+ *   trigger a deadlock.
+ * - It is not safe to call TCM transport_* functions from interrupt context.
+ */
+static void srpt_release_channel(struct srpt_rdma_ch *ch)
+{
+	schedule_work(&ch->release_work);
+}
+
+static void srpt_release_channel_work(struct work_struct *w)
+{
+	struct srpt_rdma_ch *ch;
+	struct srpt_device *sdev;
+
+	ch = container_of(w, struct srpt_rdma_ch, release_work);
+	pr_debug("ch = %p; ch->sess = %p; release_done = %p\n", ch, ch->sess,
+		 ch->release_done);
+
+	sdev = ch->sport->sdev;
+	BUG_ON(!sdev);
+
+	transport_deregister_session_configfs(ch->sess);
+	transport_deregister_session(ch->sess);
+	ch->sess = NULL;
+
+	srpt_destroy_ch_ib(ch);
+
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     srp_max_rsp_size, DMA_TO_DEVICE);
+
+	spin_lock_irq(&sdev->spinlock);
+	list_del(&ch->list);
+	spin_unlock_irq(&sdev->spinlock);
+
+	ib_destroy_cm_id(ch->cm_id);
+
+	if (ch->release_done)
+		complete(ch->release_done);
+
+	wake_up(&sdev->ch_releaseQ);
+
+	kfree(ch);
+}
+
+static struct srpt_node_acl *__srpt_lookup_acl(struct srpt_port *sport,
+					       u8 i_port_id[16])
+{
+	struct srpt_node_acl *nacl;
+
+	list_for_each_entry(nacl, &sport->port_acl_list, list)
+		if (memcmp(nacl->i_port_id, i_port_id,
+			   sizeof(nacl->i_port_id)) == 0)
+			return nacl;
+
+	return NULL;
+}
+
+static struct srpt_node_acl *srpt_lookup_acl(struct srpt_port *sport,
+					     u8 i_port_id[16])
+{
+	struct srpt_node_acl *nacl;
+
+	spin_lock_irq(&sport->port_acl_lock);
+	nacl = __srpt_lookup_acl(sport, i_port_id);
+	spin_unlock_irq(&sport->port_acl_lock);
+
+	return nacl;
+}
+
+/**
+ * srpt_cm_req_recv() - Process the event IB_CM_REQ_RECEIVED.
+ *
+ * Ownership of the cm_id is transferred to the target session if this
+ * functions returns zero. Otherwise the caller remains the owner of cm_id.
+ */
+static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
+			    struct ib_cm_req_event_param *param,
+			    void *private_data)
+{
+	struct srpt_device *sdev = cm_id->context;
+	struct srpt_port *sport = &sdev->port[param->port - 1];
+	struct srp_login_req *req;
+	struct srp_login_rsp *rsp;
+	struct srp_login_rej *rej;
+	struct ib_cm_rep_param *rep_param;
+	struct srpt_rdma_ch *ch, *tmp_ch;
+	struct srpt_node_acl *nacl;
+	u32 it_iu_len;
+	int i;
+	int ret = 0;
+
+	WARN_ON_ONCE(irqs_disabled());
+
+	if (WARN_ON(!sdev || !private_data))
+		return -EINVAL;
+
+	req = (struct srp_login_req *)private_data;
+
+	it_iu_len = be32_to_cpu(req->req_it_iu_len);
+
+	printk(KERN_INFO "Received SRP_LOGIN_REQ with i_port_id 0x%llx:0x%llx,"
+	       " t_port_id 0x%llx:0x%llx and it_iu_len %d on port %d"
+	       " (guid=0x%llx:0x%llx)\n",
+	       be64_to_cpu(*(__be64 *)&req->initiator_port_id[0]),
+	       be64_to_cpu(*(__be64 *)&req->initiator_port_id[8]),
+	       be64_to_cpu(*(__be64 *)&req->target_port_id[0]),
+	       be64_to_cpu(*(__be64 *)&req->target_port_id[8]),
+	       it_iu_len,
+	       param->port,
+	       be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[0]),
+	       be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[8]));
+
+	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) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
+		rej->reason = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
+		ret = -EINVAL;
+		printk(KERN_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 = __constant_cpu_to_be32(
+			     SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		ret = -EINVAL;
+		printk(KERN_ERR "rejected SRP_LOGIN_REQ because the target port"
+		       " has not yet been enabled\n");
+		goto reject;
+	}
+
+	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
+		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
+
+		spin_lock_irq(&sdev->spinlock);
+
+		list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
+			if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
+			    && !memcmp(ch->t_port_id, req->target_port_id, 16)
+			    && param->port == ch->sport->port
+			    && param->listen_id == ch->sport->sdev->cm_id
+			    && ch->cm_id) {
+				enum rdma_ch_state ch_state;
+
+				ch_state = srpt_get_ch_state(ch);
+				if (ch_state != CH_CONNECTING
+				    && ch_state != CH_LIVE)
+					continue;
+
+				/* found an existing channel */
+				pr_debug("Found existing channel %s"
+					 " cm_id= %p state= %d\n",
+					 ch->sess_name, ch->cm_id, ch_state);
+
+				__srpt_close_ch(ch);
+
+				rsp->rsp_flags =
+					SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
+			}
+		}
+
+		spin_unlock_irq(&sdev->spinlock);
+
+	} else
+		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
+
+	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 = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
+		ret = -ENOMEM;
+		printk(KERN_ERR "rejected SRP_LOGIN_REQ because it"
+		       " has an invalid target port identifier.\n");
+		goto reject;
+	}
+
+	ch = kzalloc(sizeof *ch, GFP_KERNEL);
+	if (!ch) {
+		rej->reason = __constant_cpu_to_be32(
+					SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		printk(KERN_ERR "rejected SRP_LOGIN_REQ because no memory.\n");
+		ret = -ENOMEM;
+		goto reject;
+	}
+
+	INIT_WORK(&ch->release_work, srpt_release_channel_work);
+	memcpy(ch->i_port_id, req->initiator_port_id, 16);
+	memcpy(ch->t_port_id, req->target_port_id, 16);
+	ch->sport = &sdev->port[param->port - 1];
+	ch->cm_id = cm_id;
+	/*
+	 * Avoid QUEUE_FULL conditions by limiting the number of buffers used
+	 * for the SRP protocol to the command queue size.
+	 */
+	ch->rq_size = SRPT_RQ_SIZE;
+	spin_lock_init(&ch->spinlock);
+	ch->state = CH_CONNECTING;
+	INIT_LIST_HEAD(&ch->cmd_wait_list);
+
+	ch->ioctx_ring = (struct srpt_send_ioctx **)
+		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
+				      sizeof(*ch->ioctx_ring[0]),
+				      srp_max_rsp_size, DMA_TO_DEVICE);
+	if (!ch->ioctx_ring)
+		goto free_ch;
+
+	INIT_LIST_HEAD(&ch->free_list);
+	for (i = 0; i < ch->rq_size; i++) {
+		ch->ioctx_ring[i]->ch = ch;
+		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
+	}
+
+	ret = srpt_create_ch_ib(ch);
+	if (ret) {
+		rej->reason = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		printk(KERN_ERR "rejected SRP_LOGIN_REQ because creating"
+		       " a new RDMA channel failed.\n");
+		goto free_ring;
+	}
+
+	ret = srpt_ch_qp_rtr(ch, ch->qp);
+	if (ret) {
+		rej->reason = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		printk(KERN_ERR "rejected SRP_LOGIN_REQ because enabling"
+		       " RTR failed (error code = %d)\n", ret);
+		goto destroy_ib;
+	}
+
+	if (use_port_guid_in_session_name) {
+		/*
+		 * If the kernel module parameter use_port_guid_in_session_name
+		 * has been specified, use a combination of the target port
+		 * GUID and the initiator port ID as the session name. This
+		 * was the original behavior of the SRP target implementation
+		 * (i.e. before the SRPT was included in OFED 1.3).
+		 */
+		snprintf(ch->sess_name, sizeof(ch->sess_name),
+			 "0x%016llx%016llx",
+			 be64_to_cpu(*(__be64 *)
+				&sdev->port[param->port - 1].gid.raw[8]),
+			 be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));
+	} else {
+		/*
+		 * Default behavior: use the initator port identifier as the
+		 * session name.
+		 */
+		snprintf(ch->sess_name, sizeof(ch->sess_name),
+			 "0x%016llx%016llx",
+			 be64_to_cpu(*(__be64 *)ch->i_port_id),
+			 be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));
+	}
+
+	pr_debug("registering session %s\n", ch->sess_name);
+
+	nacl = srpt_lookup_acl(sport, ch->i_port_id);
+	if (!nacl) {
+		printk(KERN_INFO "Rejected login because no ACL has been"
+		       " configured yet for initiator %s.\n", ch->sess_name);
+		rej->reason = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
+		goto destroy_ib;
+	}
+
+	ch->sess = transport_init_session();
+	if (!ch->sess) {
+		rej->reason = __constant_cpu_to_be32(
+				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+		pr_debug("Failed to create session\n");
+		goto deregister_session;
+	}
+	ch->sess->se_node_acl = &nacl->nacl;
+	transport_register_session(&sport->port_tpg_1, &nacl->nacl, ch->sess, ch);
+
+	pr_debug("Establish connection sess=%p name=%s cm_id=%p\n", ch->sess,
+		 ch->sess_name, ch->cm_id);
+
+	/* create srp_login_response */
+	rsp->opcode = SRP_LOGIN_RSP;
+	rsp->tag = req->tag;
+	rsp->max_it_iu_len = req->req_it_iu_len;
+	rsp->max_ti_iu_len = req->req_it_iu_len;
+	ch->max_ti_iu_len = it_iu_len;
+	rsp->buf_fmt = __constant_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 */
+	rep_param->qp_num = ch->qp->qp_num;
+	rep_param->private_data = (void *)rsp;
+	rep_param->private_data_len = sizeof *rsp;
+	rep_param->rnr_retry_count = 7;
+	rep_param->flow_control = 1;
+	rep_param->failover_accepted = 0;
+	rep_param->srq = 1;
+	rep_param->responder_resources = 4;
+	rep_param->initiator_depth = 4;
+
+	ret = ib_send_cm_rep(cm_id, rep_param);
+	if (ret) {
+		printk(KERN_ERR "sending SRP_LOGIN_REQ response failed"
+		       " (error code = %d)\n", ret);
+		goto release_channel;
+	}
+
+	spin_lock_irq(&sdev->spinlock);
+	list_add_tail(&ch->list, &sdev->rch_list);
+	spin_unlock_irq(&sdev->spinlock);
+
+	goto out;
+
+release_channel:
+	srpt_set_ch_state(ch, CH_RELEASING);
+	transport_deregister_session_configfs(ch->sess);
+
+deregister_session:
+	transport_deregister_session(ch->sess);
+	ch->sess = NULL;
+
+destroy_ib:
+	srpt_destroy_ch_ib(ch);
+
+free_ring:
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     srp_max_rsp_size, DMA_TO_DEVICE);
+
+free_ch:
+	kfree(ch);
+
+reject:
+	rej->opcode = SRP_LOGIN_REJ;
+	rej->tag = req->tag;
+	rej->buf_fmt = __constant_cpu_to_be16(SRP_BUF_FORMAT_DIRECT
+					      | SRP_BUF_FORMAT_INDIRECT);
+
+	ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
+			     (void *)rej, sizeof *rej);
+
+out:
+	kfree(rep_param);
+	kfree(rsp);
+	kfree(rej);
+
+	return ret;
+}
+
+static void srpt_cm_rej_recv(struct ib_cm_id *cm_id)
+{
+	printk(KERN_INFO "Received IB REJ for cm_id %p.\n", cm_id);
+	srpt_drain_channel(cm_id);
+}
+
+/**
+ * srpt_cm_rtu_recv() - Process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event.
+ *
+ * An IB_CM_RTU_RECEIVED message indicates that the connection is established
+ * and that the recipient may begin transmitting (RTU = ready to use).
+ */
+static void srpt_cm_rtu_recv(struct ib_cm_id *cm_id)
+{
+	struct srpt_rdma_ch *ch;
+	int ret;
+
+	ch = srpt_find_channel(cm_id->context, cm_id);
+	BUG_ON(!ch);
+
+	if (srpt_test_and_set_ch_state(ch, CH_CONNECTING, CH_LIVE)) {
+		struct srpt_recv_ioctx *ioctx, *ioctx_tmp;
+
+		ret = srpt_ch_qp_rts(ch, ch->qp);
+
+		list_for_each_entry_safe(ioctx, ioctx_tmp, &ch->cmd_wait_list,
+					 wait_list) {
+			list_del(&ioctx->wait_list);
+			srpt_handle_new_iu(ch, ioctx, NULL);
+		}
+		if (ret)
+			srpt_close_ch(ch);
+	}
+}
+
+static void srpt_cm_timewait_exit(struct ib_cm_id *cm_id)
+{
+	printk(KERN_INFO "Received IB TimeWait exit for cm_id %p.\n", cm_id);
+	srpt_drain_channel(cm_id);
+}
+
+static void srpt_cm_rep_error(struct ib_cm_id *cm_id)
+{
+	printk(KERN_INFO "Received IB REP error for cm_id %p.\n", cm_id);
+	srpt_drain_channel(cm_id);
+}
+
+/**
+ * srpt_cm_dreq_recv() - Process reception of a DREQ message.
+ */
+static void srpt_cm_dreq_recv(struct ib_cm_id *cm_id)
+{
+	struct srpt_rdma_ch *ch;
+	unsigned long flags;
+	bool send_drep = false;
+
+	ch = srpt_find_channel(cm_id->context, cm_id);
+	BUG_ON(!ch);
+
+	pr_debug("cm_id= %p ch->state= %d\n", cm_id, srpt_get_ch_state(ch));
+
+	spin_lock_irqsave(&ch->spinlock, flags);
+	switch (ch->state) {
+	case CH_CONNECTING:
+	case CH_LIVE:
+		send_drep = true;
+		ch->state = CH_DISCONNECTING;
+		break;
+	case CH_DISCONNECTING:
+	case CH_DRAINING:
+	case CH_RELEASING:
+		__WARN();
+		break;
+	}
+	spin_unlock_irqrestore(&ch->spinlock, flags);
+
+	if (send_drep) {
+		if (ib_send_cm_drep(ch->cm_id, NULL, 0) < 0)
+			printk(KERN_ERR "Sending IB DREP failed.\n");
+		printk(KERN_INFO "Received DREQ and sent DREP for session %s.\n",
+		       ch->sess_name);
+	}
+}
+
+/**
+ * srpt_cm_drep_recv() - Process reception of a DREP message.
+ */
+static void srpt_cm_drep_recv(struct ib_cm_id *cm_id)
+{
+	printk(KERN_INFO "Received InfiniBand DREP message for cm_id %p.\n",
+	       cm_id);
+	srpt_drain_channel(cm_id);
+}
+
+/**
+ * srpt_cm_handler() - IB connection manager callback function.
+ *
+ * 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, struct ib_cm_event *event)
+{
+	int ret;
+
+	ret = 0;
+	switch (event->event) {
+	case IB_CM_REQ_RECEIVED:
+		ret = srpt_cm_req_recv(cm_id, &event->param.req_rcvd,
+				       event->private_data);
+		break;
+	case IB_CM_REJ_RECEIVED:
+		srpt_cm_rej_recv(cm_id);
+		break;
+	case IB_CM_RTU_RECEIVED:
+	case IB_CM_USER_ESTABLISHED:
+		srpt_cm_rtu_recv(cm_id);
+		break;
+	case IB_CM_DREQ_RECEIVED:
+		srpt_cm_dreq_recv(cm_id);
+		break;
+	case IB_CM_DREP_RECEIVED:
+		srpt_cm_drep_recv(cm_id);
+		break;
+	case IB_CM_TIMEWAIT_EXIT:
+		srpt_cm_timewait_exit(cm_id);
+		break;
+	case IB_CM_REP_ERROR:
+		srpt_cm_rep_error(cm_id);
+		break;
+	case IB_CM_DREQ_ERROR:
+		printk(KERN_INFO "Received IB DREQ ERROR event.\n");
+		break;
+	case IB_CM_MRA_RECEIVED:
+		printk(KERN_INFO "Received IB MRA event\n");
+		break;
+	default:
+		printk(KERN_ERR "received unrecognized IB CM event %d\n",
+		       event->event);
+		break;
+	}
+
+	return ret;
+}
+
+/**
+ * srpt_perform_rdmas() - Perform IB RDMA.
+ *
+ * Returns zero upon success or a negative number upon failure.
+ */
+static int srpt_perform_rdmas(struct srpt_rdma_ch *ch,
+			      struct srpt_send_ioctx *ioctx)
+{
+	struct ib_send_wr wr;
+	struct ib_send_wr *bad_wr;
+	struct rdma_iu *riu;
+	int i;
+	int ret;
+	int sq_wr_avail;
+	enum dma_data_direction dir;
+
+	dir = ioctx->cmd.data_direction;
+	if (dir == DMA_TO_DEVICE) {
+		/* write */
+		ret = -ENOMEM;
+		sq_wr_avail = atomic_sub_return(ioctx->n_rdma,
+						 &ch->sq_wr_avail);
+		if (sq_wr_avail < 0) {
+			printk(KERN_WARNING "IB send queue full (needed %d)\n",
+			       ioctx->n_rdma);
+			goto out;
+		}
+	}
+
+	ret = 0;
+	riu = ioctx->rdma_ius;
+	memset(&wr, 0, sizeof wr);
+
+	for (i = 0; i < ioctx->n_rdma; ++i, ++riu) {
+		if (dir == DMA_FROM_DEVICE) {
+			wr.opcode = IB_WR_RDMA_WRITE;
+			wr.wr_id = encode_wr_id(IB_WC_RDMA_WRITE,
+						ioctx->ioctx.index);
+		} else {
+			wr.opcode = IB_WR_RDMA_READ;
+			wr.wr_id = encode_wr_id(IB_WC_RDMA_READ,
+						ioctx->ioctx.index);
+		}
+		wr.next = NULL;
+		wr.wr.rdma.remote_addr = riu->raddr;
+		wr.wr.rdma.rkey = riu->rkey;
+		wr.num_sge = riu->sge_cnt;
+		wr.sg_list = riu->sge;
+
+		/* only get completion event for the last rdma write */
+		if (i == (ioctx->n_rdma - 1) && dir == DMA_TO_DEVICE)
+			wr.send_flags = IB_SEND_SIGNALED;
+
+		ret = ib_post_send(ch->qp, &wr, &bad_wr);
+		if (ret)
+			goto out;
+	}
+
+out:
+	if (unlikely(dir == DMA_TO_DEVICE && ret < 0))
+		atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
+	return ret;
+}
+
+/**
+ * srpt_xfer_data() - Start data transfer from initiator to target.
+ */
+static int srpt_xfer_data(struct srpt_rdma_ch *ch,
+			  struct srpt_send_ioctx *ioctx)
+{
+	int ret;
+
+	ret = srpt_map_sg_to_ib_sge(ch, ioctx);
+	if (ret) {
+		printk(KERN_ERR "%s[%d] ret=%d\n", __func__, __LINE__, ret);
+		goto out;
+	}
+
+	ret = srpt_perform_rdmas(ch, ioctx);
+	if (ret) {
+		if (ret == -EAGAIN || ret == -ENOMEM)
+			printk(KERN_INFO "%s[%d] queue full -- ret=%d\n",
+				   __func__, __LINE__, ret);
+		else
+			printk(KERN_ERR "%s[%d] fatal error -- ret=%d\n",
+			       __func__, __LINE__, ret);
+		goto out_unmap;
+	}
+
+out:
+	return ret;
+out_unmap:
+	srpt_unmap_sg_to_ib_sge(ch, ioctx);
+	goto out;
+}
+
+static int srpt_write_pending_status(struct se_cmd *se_cmd)
+{
+	struct srpt_send_ioctx *ioctx;
+
+	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
+	return srpt_get_cmd_state(ioctx) == SRPT_STATE_NEED_DATA;
+}
+
+/*
+ * srpt_write_pending() - Start data transfer from initiator to target (write).
+ */
+static int srpt_write_pending(struct se_cmd *se_cmd)
+{
+	struct srpt_rdma_ch *ch;
+	struct srpt_send_ioctx *ioctx;
+	enum srpt_command_state new_state;
+	enum rdma_ch_state ch_state;
+	int ret;
+
+	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
+
+	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
+	WARN_ON(new_state == SRPT_STATE_DONE);
+
+	ch = ioctx->ch;
+	BUG_ON(!ch);
+
+	ch_state = srpt_get_ch_state(ch);
+	switch (ch_state) {
+	case CH_CONNECTING:
+		/* This code should never be reached. */
+		__WARN();
+		ret = -EINVAL;
+		goto out;
+	case CH_LIVE:
+		break;
+	case CH_DISCONNECTING:
+	case CH_DRAINING:
+	case CH_RELEASING:
+		pr_debug("cmd with tag %lld: channel disconnecting\n",
+			 ioctx->tag);
+		srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN);
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = srpt_xfer_data(ch, ioctx);
+
+out:
+	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() - Transmits the response to a SCSI 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 int srpt_queue_response(struct se_cmd *cmd)
+{
+	struct srpt_rdma_ch *ch;
+	struct srpt_send_ioctx *ioctx;
+	enum srpt_command_state state;
+	unsigned long flags;
+	int ret;
+	enum dma_data_direction dir;
+	int resp_len;
+	u8 srp_tm_status;
+
+	ret = 0;
+
+	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
+	ch = ioctx->ch;
+	BUG_ON(!ch);
+
+	spin_lock_irqsave(&ioctx->spinlock, flags);
+	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:
+		printk(KERN_ERR "ch %p; cmd %d: unexpected command state %d\n",
+		       ch, ioctx->ioctx.index, ioctx->state);
+		__WARN();
+		break;
+	}
+	spin_unlock_irqrestore(&ioctx->spinlock, flags);
+
+	if (unlikely(transport_check_aborted_status(&ioctx->cmd, false)
+		     || WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))) {
+		atomic_inc(&ch->req_lim_delta);
+		srpt_abort_cmd(ioctx);
+		goto out;
+	}
+
+	dir = ioctx->cmd.data_direction;
+
+	/* For read commands, transfer the data to the initiator. */
+	if (dir == DMA_FROM_DEVICE && ioctx->cmd.data_length &&
+	    !ioctx->queue_status_only) {
+		ret = srpt_xfer_data(ch, ioctx);
+		if (ret) {
+			printk(KERN_ERR "xfer_data failed for tag %llu\n",
+			       ioctx->tag);
+			goto out;
+		}
+	}
+
+	if (state != SRPT_STATE_MGMT)
+		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->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->tag);
+	}
+	ret = srpt_post_send(ch, ioctx, resp_len);
+	if (ret) {
+		printk(KERN_ERR "sending cmd response failed for tag %llu\n",
+		       ioctx->tag);
+		srpt_unmap_sg_to_ib_sge(ch, ioctx);
+		srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
+		kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
+	}
+
+out:
+	return ret;
+}
+
+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;
+	return srpt_queue_response(cmd);
+}
+
+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);
+}
+
+static int srpt_ch_list_empty(struct srpt_device *sdev)
+{
+	int res;
+
+	spin_lock_irq(&sdev->spinlock);
+	res = list_empty(&sdev->rch_list);
+	spin_unlock_irq(&sdev->spinlock);
+
+	return res;
+}
+
+/**
+ * srpt_release_sdev() - Free the channel resources associated with a target.
+ */
+static int srpt_release_sdev(struct srpt_device *sdev)
+{
+	struct srpt_rdma_ch *ch, *tmp_ch;
+	int res;
+
+	WARN_ON_ONCE(irqs_disabled());
+
+	BUG_ON(!sdev);
+
+	spin_lock_irq(&sdev->spinlock);
+	list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list)
+		__srpt_close_ch(ch);
+	spin_unlock_irq(&sdev->spinlock);
+
+	res = wait_event_interruptible(sdev->ch_releaseQ,
+				       srpt_ch_list_empty(sdev));
+	if (res)
+		printk(KERN_ERR "%s: interrupted.\n", __func__);
+
+	return 0;
+}
+
+static struct srpt_port *__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->port_guid, name))
+				return sport;
+		}
+	}
+
+	return NULL;
+}
+
+static struct srpt_port *srpt_lookup_port(const char *name)
+{
+	struct srpt_port *sport;
+
+	spin_lock(&srpt_dev_lock);
+	sport = __srpt_lookup_port(name);
+	spin_unlock(&srpt_dev_lock);
+
+	return sport;
+}
+
+/**
+ * srpt_add_one() - Infiniband device addition callback function.
+ */
+static void srpt_add_one(struct ib_device *device)
+{
+	struct srpt_device *sdev;
+	struct srpt_port *sport;
+	struct ib_srq_init_attr srq_attr;
+	int i;
+
+	pr_debug("device = %p, device->dma_ops = %p\n", device,
+		 device->dma_ops);
+
+	sdev = kzalloc(sizeof *sdev, GFP_KERNEL);
+	if (!sdev)
+		goto err;
+
+	sdev->device = device;
+	INIT_LIST_HEAD(&sdev->rch_list);
+	init_waitqueue_head(&sdev->ch_releaseQ);
+	spin_lock_init(&sdev->spinlock);
+
+	if (ib_query_device(device, &sdev->dev_attr))
+		goto free_dev;
+
+	sdev->pd = ib_alloc_pd(device);
+	if (IS_ERR(sdev->pd))
+		goto free_dev;
+
+	sdev->mr = ib_get_dma_mr(sdev->pd, IB_ACCESS_LOCAL_WRITE);
+	if (IS_ERR(sdev->mr))
+		goto err_pd;
+
+	sdev->srq_size = min(srpt_srq_size, sdev->dev_attr.max_srq_wr);
+
+	srq_attr.event_handler = srpt_srq_event;
+	srq_attr.srq_context = (void *)sdev;
+	srq_attr.attr.max_wr = sdev->srq_size;
+	srq_attr.attr.max_sge = 1;
+	srq_attr.attr.srq_limit = 0;
+
+	sdev->srq = ib_create_srq(sdev->pd, &srq_attr);
+	if (IS_ERR(sdev->srq))
+		goto err_mr;
+
+	pr_debug("%s: create SRQ #wr= %d max_allow=%d dev= %s\n",
+		 __func__, sdev->srq_size, sdev->dev_attr.max_srq_wr,
+		 device->name);
+
+	if (!srpt_service_guid)
+		srpt_service_guid = be64_to_cpu(device->node_guid);
+
+	sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
+	if (IS_ERR(sdev->cm_id))
+		goto err_srq;
+
+	/* 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
+	 */
+	if (ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0, NULL))
+		goto err_cm;
+
+	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
+			      srpt_event_handler);
+	if (ib_register_event_handler(&sdev->event_handler))
+		goto err_cm;
+
+	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
+		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
+				      sizeof(*sdev->ioctx_ring[0]),
+				      srp_max_req_size, DMA_FROM_DEVICE);
+	if (!sdev->ioctx_ring)
+		goto err_event;
+
+	for (i = 0; i < sdev->srq_size; ++i)
+		srpt_post_recv(sdev, sdev->ioctx_ring[i]);
+
+	WARN_ON(sdev->device->phys_port_cnt
+		> sizeof(sdev->port)/sizeof(sdev->port[0]));
+
+	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
+		sport = &sdev->port[i - 1];
+		sport->sdev = sdev;
+		sport->port = i;
+		INIT_WORK(&sport->work, srpt_refresh_port_work);
+		INIT_LIST_HEAD(&sport->port_acl_list);
+		spin_lock_init(&sport->port_acl_lock);
+
+		sprintf(sport->port_guid, "0x0000000000000000%04x%04x%04x%04x",
+                                be16_to_cpu(((__be16 *)&device->node_guid)[0]),
+                                be16_to_cpu(((__be16 *)&device->node_guid)[1]),
+                                be16_to_cpu(((__be16 *)&device->node_guid)[2]),
+                                be16_to_cpu(((__be16 *)&device->node_guid)[3]) + i);
+
+		if (srpt_refresh_port(sport)) {
+			printk(KERN_ERR "MAD registration failed for %s-%d.\n",
+			       srpt_sdev_name(sdev), i);
+			goto err_ring;
+		}
+	}
+
+	spin_lock(&srpt_dev_lock);
+	list_add_tail(&sdev->list, &srpt_dev_list);
+	spin_unlock(&srpt_dev_lock);
+
+out:
+	ib_set_client_data(device, &srpt_client, sdev);
+	pr_debug("added %s.\n", device->name);
+	return;
+
+err_ring:
+	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
+			     sdev->srq_size, srp_max_req_size,
+			     DMA_FROM_DEVICE);
+err_event:
+	ib_unregister_event_handler(&sdev->event_handler);
+err_cm:
+	ib_destroy_cm_id(sdev->cm_id);
+err_srq:
+	ib_destroy_srq(sdev->srq);
+err_mr:
+	ib_dereg_mr(sdev->mr);
+err_pd:
+	ib_dealloc_pd(sdev->pd);
+free_dev:
+	kfree(sdev);
+err:
+	sdev = NULL;
+	printk(KERN_INFO "%s(%s) failed.\n", __func__, device->name);
+	goto out;
+}
+
+/**
+ * srpt_remove_one() - InfiniBand device removal callback function.
+ */
+static void srpt_remove_one(struct ib_device *device)
+{
+	struct srpt_device *sdev;
+	int i;
+
+	sdev = ib_get_client_data(device, &srpt_client);
+	if (!sdev) {
+		printk(KERN_INFO "%s(%s): nothing to do.\n", __func__,
+		       device->name);
+		return;
+	}
+
+	srpt_unregister_mad_agent(sdev);
+
+	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);
+
+	ib_destroy_cm_id(sdev->cm_id);
+
+	/*
+	 * 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);
+	srpt_release_sdev(sdev);
+
+	ib_destroy_srq(sdev->srq);
+	ib_dereg_mr(sdev->mr);
+	ib_dealloc_pd(sdev->pd);
+
+	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
+			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
+	sdev->ioctx_ring = NULL;
+	kfree(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 char *srpt_get_fabric_name(void)
+{
+	return "srpt";
+}
+
+static u8 srpt_get_fabric_proto_ident(struct se_portal_group *se_tpg)
+{
+	return SCSI_TRANSPORTID_PROTOCOLID_SRP;
+}
+
+static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
+{
+	struct srpt_port *sport = container_of(tpg, struct srpt_port, port_tpg_1);
+
+	return sport->port_guid;
+}
+
+static u16 srpt_get_tag(struct se_portal_group *tpg)
+{
+	return 1;
+}
+
+static u32 srpt_get_default_depth(struct se_portal_group *se_tpg)
+{
+	return 1;
+}
+
+static u32 srpt_get_pr_transport_id(struct se_portal_group *se_tpg,
+				    struct se_node_acl *se_nacl,
+				    struct t10_pr_registration *pr_reg,
+				    int *format_code, unsigned char *buf)
+{
+	struct srpt_node_acl *nacl;
+	struct spc_rdma_transport_id *tr_id;
+
+	nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
+	tr_id = (void *)buf;
+	tr_id->protocol_identifier = SCSI_TRANSPORTID_PROTOCOLID_SRP;
+	memcpy(tr_id->i_port_id, nacl->i_port_id, sizeof(tr_id->i_port_id));
+	return sizeof(*tr_id);
+}
+
+static u32 srpt_get_pr_transport_id_len(struct se_portal_group *se_tpg,
+					struct se_node_acl *se_nacl,
+					struct t10_pr_registration *pr_reg,
+					int *format_code)
+{
+	*format_code = 0;
+	return sizeof(struct spc_rdma_transport_id);
+}
+
+static char *srpt_parse_pr_out_transport_id(struct se_portal_group *se_tpg,
+					    const char *buf, u32 *out_tid_len,
+					    char **port_nexus_ptr)
+{
+	struct spc_rdma_transport_id *tr_id;
+
+	*port_nexus_ptr = NULL;
+	*out_tid_len = sizeof(struct spc_rdma_transport_id);
+	tr_id = (void *)buf;
+	return (char *)tr_id->i_port_id;
+}
+
+static struct se_node_acl *srpt_alloc_fabric_acl(struct se_portal_group *se_tpg)
+{
+	struct srpt_node_acl *nacl;
+
+	nacl = kzalloc(sizeof(struct srpt_node_acl), GFP_KERNEL);
+	if (!nacl) {
+		printk(KERN_ERR "Unable to alocate struct srpt_node_acl\n");
+		return NULL;
+	}
+
+	return &nacl->nacl;
+}
+
+static void srpt_release_fabric_acl(struct se_portal_group *se_tpg,
+				    struct se_node_acl *se_nacl)
+{
+	struct srpt_node_acl *nacl;
+
+	nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
+	kfree(nacl);
+}
+
+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)
+{
+}
+
+/**
+ * srpt_shutdown_session() - Whether or not a session may be shut down.
+ */
+static int srpt_shutdown_session(struct se_session *se_sess)
+{
+	return true;
+}
+
+/**
+ * srpt_close_session() - Forcibly close a 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)
+{
+	DECLARE_COMPLETION_ONSTACK(release_done);
+	struct srpt_rdma_ch *ch;
+	struct srpt_device *sdev;
+	int res;
+
+	ch = se_sess->fabric_sess_ptr;
+	WARN_ON(ch->sess != se_sess);
+
+	pr_debug("ch %p state %d\n", ch, srpt_get_ch_state(ch));
+
+	sdev = ch->sport->sdev;
+	spin_lock_irq(&sdev->spinlock);
+	BUG_ON(ch->release_done);
+	ch->release_done = &release_done;
+	__srpt_close_ch(ch);
+	spin_unlock_irq(&sdev->spinlock);
+
+	res = wait_for_completion_timeout(&release_done, 60 * HZ);
+	WARN_ON(res <= 0);
+}
+
+/**
+ * To do: Find out whether stop_session() has a meaning for transports
+ * other than iSCSI.
+ */
+static void srpt_stop_session(struct se_session *se_sess, int sess_sleep,
+			      int conn_sleep)
+{
+}
+
+static void srpt_reset_nexus(struct se_session *sess)
+{
+	printk(KERN_ERR "This is the SRP protocol, not iSCSI\n");
+}
+
+static int srpt_sess_logged_in(struct se_session *se_sess)
+{
+	return true;
+}
+
+/**
+ * srpt_sess_get_index() - Return the value of scsiAttIntrPortIndex (SCSI-MIB).
+ *
+ * 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)
+{
+}
+
+static u32 srpt_get_task_tag(struct se_cmd *se_cmd)
+{
+	struct srpt_send_ioctx *ioctx;
+
+	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
+	return ioctx->tag;
+}
+
+/* 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 srpt_get_cmd_state(ioctx);
+}
+
+static void srpt_new_cmd_failure(struct se_cmd *se_cmd)
+{
+}
+
+static u16 srpt_set_fabric_sense_len(struct se_cmd *cmd, u32 sense_length)
+{
+	return 0;
+}
+
+static u16 srpt_get_fabric_sense_len(void)
+{
+	return 0;
+}
+
+static int srpt_is_state_remove(struct se_cmd *se_cmd)
+{
+	return 0;
+}
+
+static u64 srpt_pack_lun(unsigned int lun)
+{
+	WARN_ON(lun >= 256);
+	/* Caller wants this byte-swapped */
+	return cpu_to_le64((lun & 0xff) << 8);
+}
+
+/**
+ * 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 (strnicmp(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);
+	hex2bin(i_port_id + leading_zero_bytes, p, count);
+	ret = 0;
+out:
+	return ret;
+}
+
+/*
+ * configfs callback function invoked for
+ * mkdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
+ */
+static struct se_node_acl *srpt_make_nodeacl(struct se_portal_group *tpg,
+					     struct config_group *group,
+					     const char *name)
+{
+	struct srpt_port *sport = container_of(tpg, struct srpt_port, port_tpg_1);
+	struct se_node_acl *se_nacl, *se_nacl_new;
+	struct srpt_node_acl *nacl;
+	int ret = 0;
+	u32 nexus_depth = 1;
+	u8 i_port_id[16];
+
+	if (srpt_parse_i_port_id(i_port_id, name) < 0) {
+		printk(KERN_ERR "invalid initiator port ID %s\n", name);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	se_nacl_new = srpt_alloc_fabric_acl(tpg);
+	if (!se_nacl_new)
+		goto err;
+	/*
+	 * nacl_new may be released by core_tpg_add_initiator_node_acl()
+	 * when converting a node ACL from demo mode to explict
+	 */
+	se_nacl = core_tpg_add_initiator_node_acl(tpg, se_nacl_new, name,
+						  nexus_depth);
+	if (IS_ERR(se_nacl)) {
+		ret = PTR_ERR(se_nacl);
+		goto err;
+	}
+	/* Locate our struct srpt_node_acl and set sdev and i_port_id. */
+	nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
+	memcpy(&nacl->i_port_id[0], &i_port_id[0], 16);
+	nacl->sport = sport;
+
+	spin_lock_irq(&sport->port_acl_lock);
+	list_add_tail(&nacl->list, &sport->port_acl_list);
+	spin_unlock_irq(&sport->port_acl_lock);
+
+	return se_nacl;
+err:
+	return ERR_PTR(ret);
+}
+
+/*
+ * configfs callback function invoked for
+ * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
+ */
+static void srpt_drop_nodeacl(struct se_node_acl *se_nacl)
+{
+	struct srpt_node_acl *nacl;
+	struct srpt_device *sdev;
+	struct srpt_port *sport;
+
+	nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
+	sport = nacl->sport;
+	sdev = sport->sdev;
+	spin_lock_irq(&sport->port_acl_lock);
+	list_del(&nacl->list);
+	spin_unlock_irq(&sport->port_acl_lock);
+	core_tpg_del_initiator_node_acl(&sport->port_tpg_1, se_nacl, 1);
+	srpt_release_fabric_acl(NULL, se_nacl);
+}
+
+static ssize_t srpt_tpg_show_enable(
+	struct se_portal_group *se_tpg,
+	char *page)
+{
+	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
+
+	return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
+}
+
+static ssize_t srpt_tpg_store_enable(
+	struct se_portal_group *se_tpg,
+	const char *page,
+	size_t count)
+{
+	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
+	unsigned long tmp;
+        int ret;
+
+	ret = strict_strtoul(page, 0, &tmp);
+	if (ret < 0) {
+		printk(KERN_ERR "Unable to extract srpt_tpg_store_enable\n");
+		return -EINVAL;
+	}
+
+	if ((tmp != 0) && (tmp != 1)) {
+		printk(KERN_ERR "Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
+		return -EINVAL;
+	}
+	if (tmp == 1)
+		sport->enabled = true;
+	else
+		sport->enabled = false;
+
+	return count;
+}
+
+TF_TPG_BASE_ATTR(srpt, enable, S_IRUGO | S_IWUSR);
+
+static struct configfs_attribute *srpt_tpg_attrs[] = {
+	&srpt_tpg_enable.attr,
+	NULL,
+};
+
+/**
+ * configfs callback invoked for
+ * mkdir /sys/kernel/config/target/$driver/$port/$tpg
+ */
+static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
+					     struct config_group *group,
+					     const char *name)
+{
+	struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);
+	int res;
+
+	/* Initialize sport->port_wwn and sport->port_tpg_1 */
+	res = core_tpg_register(&srpt_target->tf_ops, &sport->port_wwn,
+			&sport->port_tpg_1, sport, TRANSPORT_TPG_TYPE_NORMAL);
+	if (res)
+		return ERR_PTR(res);
+
+	return &sport->port_tpg_1;
+}
+
+/**
+ * configfs callback invoked for
+ * rmdir /sys/kernel/config/target/$driver/$port/$tpg
+ */
+static void srpt_drop_tpg(struct se_portal_group *tpg)
+{
+	struct srpt_port *sport = container_of(tpg,
+				struct srpt_port, port_tpg_1);
+
+	sport->enabled = false;
+	core_tpg_deregister(&sport->port_tpg_1);
+}
+
+/**
+ * configfs callback invoked for
+ * mkdir /sys/kernel/config/target/$driver/$target
+ */
+static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
+				      struct config_group *group,
+				      const char *name)
+{
+	struct srpt_port *sport;
+	int ret;
+
+	sport = srpt_lookup_port(name);
+	pr_debug("make_tport(%s)\n", name);
+	ret = -EINVAL;
+	if (!sport)
+		goto err;
+
+	return &sport->port_wwn;
+
+err:
+	return ERR_PTR(ret);
+}
+
+/**
+ * configfs callback invoked for
+ * rmdir /sys/kernel/config/target/$driver/$target
+ */
+static void srpt_drop_tport(struct se_wwn *wwn)
+{
+	struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);
+
+	pr_debug("drop_tport(%s\n", config_item_name(&sport->port_wwn.wwn_group.cg_item));
+}
+
+static ssize_t srpt_wwn_show_attr_version(struct target_fabric_configfs *tf,
+					      char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
+}
+
+TF_WWN_ATTR_RO(srpt, version);
+
+static struct configfs_attribute *srpt_wwn_attrs[] = {
+	&srpt_wwn_version.attr,
+	NULL,
+};
+
+static struct target_core_fabric_ops srpt_template = {
+	.get_fabric_name		= srpt_get_fabric_name,
+	.get_fabric_proto_ident		= srpt_get_fabric_proto_ident,
+	.tpg_get_wwn			= srpt_get_fabric_wwn,
+	.tpg_get_tag			= srpt_get_tag,
+	.tpg_get_default_depth		= srpt_get_default_depth,
+	.tpg_get_pr_transport_id	= srpt_get_pr_transport_id,
+	.tpg_get_pr_transport_id_len	= srpt_get_pr_transport_id_len,
+	.tpg_parse_pr_out_transport_id	= srpt_parse_pr_out_transport_id,
+	.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_alloc_fabric_acl		= srpt_alloc_fabric_acl,
+	.tpg_release_fabric_acl		= srpt_release_fabric_acl,
+	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
+	.release_cmd_to_pool		= srpt_release_cmd,
+	.release_cmd_direct		= srpt_release_cmd,
+	.check_stop_free		= srpt_check_stop_free,
+	.shutdown_session		= srpt_shutdown_session,
+	.close_session			= srpt_close_session,
+	.stop_session			= srpt_stop_session,
+	.fall_back_to_erl0		= srpt_reset_nexus,
+	.sess_logged_in			= srpt_sess_logged_in,
+	.sess_get_index			= srpt_sess_get_index,
+	.sess_get_initiator_sid		= NULL,
+	.write_pending			= srpt_write_pending,
+	.write_pending_status		= srpt_write_pending_status,
+	.set_default_node_attributes	= srpt_set_default_node_attrs,
+	.get_task_tag			= srpt_get_task_tag,
+	.get_cmd_state			= srpt_get_tcm_cmd_state,
+	.new_cmd_failure		= srpt_new_cmd_failure,
+	.queue_data_in			= srpt_queue_response,
+	.queue_status			= srpt_queue_status,
+	.queue_tm_rsp			= srpt_queue_response,
+	.get_fabric_sense_len		= srpt_get_fabric_sense_len,
+	.set_fabric_sense_len		= srpt_set_fabric_sense_len,
+	.is_state_remove		= srpt_is_state_remove,
+	.pack_lun			= srpt_pack_lun,
+	/*
+	 * 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_drop_tpg		= srpt_drop_tpg,
+	.fabric_post_link		= NULL,
+	.fabric_pre_unlink		= NULL,
+	.fabric_make_np			= NULL,
+	.fabric_drop_np			= NULL,
+	.fabric_make_nodeacl		= srpt_make_nodeacl,
+	.fabric_drop_nodeacl		= srpt_drop_nodeacl,
+};
+
+/**
+ * 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) {
+		printk(KERN_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 (srp_max_rsp_size < MIN_MAX_RSP_SIZE) {
+		printk(KERN_ERR "invalid value %d for kernel module parameter"
+		       " srp_max_rsp_size -- must be at least %d.\n",
+		       srp_max_rsp_size, MIN_MAX_RSP_SIZE);
+		goto out;
+	}
+
+	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
+	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
+		printk(KERN_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;
+	}
+
+	if (srpt_sq_size < MIN_SRPT_SQ_SIZE) {
+		printk(KERN_ERR "invalid value %d for kernel module parameter"
+		       " srpt_sq_size -- must be at least %d.\n", srpt_srq_size,
+		       MIN_SRPT_SQ_SIZE);
+		goto out;
+	}
+
+	spin_lock_init(&srpt_dev_lock);
+	INIT_LIST_HEAD(&srpt_dev_list);
+
+	ret = -ENODEV;
+	srpt_target = target_fabric_configfs_init(THIS_MODULE, "srpt");
+	if (!srpt_target) {
+		printk(KERN_ERR "couldn't register\n");
+		goto out;
+	}
+
+	srpt_target->tf_ops = srpt_template;
+
+	/* Enable SG chaining */
+	srpt_target->tf_ops.task_sg_chaining = true;
+
+	/*
+	 * Set up default attribute lists.
+	 */
+	srpt_target->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = srpt_wwn_attrs;
+	srpt_target->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = srpt_tpg_attrs;
+	srpt_target->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_nacl_base_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_nacl_auth_cit.ct_attrs = NULL;
+	srpt_target->tf_cit_tmpl.tfc_tpg_nacl_param_cit.ct_attrs = NULL;
+
+	ret = target_fabric_configfs_register(srpt_target);
+	if (ret < 0) {
+		printk(KERN_ERR "couldn't register\n");
+		goto out_free_target;
+	}
+
+	ret = ib_register_client(&srpt_client);
+	if (ret) {
+		printk(KERN_ERR "couldn't register IB client\n");
+		goto out_unregister_target;
+	}
+
+	return 0;
+
+out_unregister_target:
+	target_fabric_configfs_deregister(srpt_target);
+	srpt_target = NULL;
+out_free_target:
+	if (srpt_target)
+		target_fabric_configfs_free(srpt_target);
+out:
+	return ret;
+}
+
+static void __exit srpt_cleanup_module(void)
+{
+	ib_unregister_client(&srpt_client);
+	target_fabric_configfs_deregister(srpt_target);
+	srpt_target = NULL;
+}
+
+module_init(srpt_init_module);
+module_exit(srpt_cleanup_module);
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
new file mode 100644
index 0000000..045fb7b
--- /dev/null
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -0,0 +1,409 @@
+/*
+ * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
+ * Copyright (C) 2009 - 2010 Bart Van Assche <bvanassche@xxxxxxx>.
+ *
+ * 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.
+ *
+ */
+
+#ifndef IB_SRPT_H
+#define IB_SRPT_H
+
+#include <linux/version.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/ib_sa.h>
+#include <rdma/ib_cm.h>
+
+#include <scsi/srp.h>
+
+#include "ib_dm_mad.h"
+
+/*
+ * The prefix the ServiceName field must start with in the device management
+ * ServiceEntries attribute pair. See also the SRP specification.
+ */
+#define SRP_SERVICE_NAME_PREFIX		"SRP.T10:"
+
+enum {
+	/*
+	 * SRP IOControllerProfile attributes for SRP target ports that have
+	 * not been defined in <scsi/srp.h>. Source: section B.7, table B.7
+	 * in the SRP specification.
+	 */
+	SRP_PROTOCOL = 0x0108,
+	SRP_PROTOCOL_VERSION = 0x0001,
+	SRP_IO_SUBCLASS = 0x609e,
+	SRP_SEND_TO_IOC = 0x01,
+	SRP_SEND_FROM_IOC = 0x02,
+	SRP_RDMA_READ_FROM_IOC = 0x08,
+	SRP_RDMA_WRITE_FROM_IOC = 0x20,
+
+	/*
+	 * srp_login_cmd.req_flags bitmasks. See also table 9 in the SRP
+	 * specification.
+	 */
+	SRP_MTCH_ACTION = 0x03, /* MULTI-CHANNEL ACTION */
+	SRP_LOSOLNT = 0x10, /* logout solicited notification */
+	SRP_CRSOLNT = 0x20, /* credit request solicited notification */
+	SRP_AESOLNT = 0x40, /* asynchronous event solicited notification */
+
+	/*
+	 * srp_cmd.sol_nt / srp_tsk_mgmt.sol_not bitmasks. See also tables
+	 * 18 and 20 in the SRP specification.
+	 */
+	SRP_SCSOLNT = 0x02, /* SCSOLNT = successful solicited notification */
+	SRP_UCSOLNT = 0x04, /* UCSOLNT = unsuccessful solicited notification */
+
+	/*
+	 * srp_rsp.sol_not / srp_t_logout.sol_not bitmasks. See also tables
+	 * 16 and 22 in the SRP specification.
+	 */
+	SRP_SOLNT = 0x01, /* SOLNT = solicited notification */
+
+	/* See also table 24 in the SRP specification. */
+	SRP_TSK_MGMT_SUCCESS = 0x00,
+	SRP_TSK_MGMT_FUNC_NOT_SUPP = 0x04,
+	SRP_TSK_MGMT_FAILED = 0x05,
+
+	/* See also table 21 in the SRP specification. */
+	SRP_CMD_SIMPLE_Q = 0x0,
+	SRP_CMD_HEAD_OF_Q = 0x1,
+	SRP_CMD_ORDERED_Q = 0x2,
+	SRP_CMD_ACA = 0x4,
+
+	SRP_LOGIN_RSP_MULTICHAN_NO_CHAN = 0x0,
+	SRP_LOGIN_RSP_MULTICHAN_TERMINATED = 0x1,
+	SRP_LOGIN_RSP_MULTICHAN_MAINTAINED = 0x2,
+
+	SRPT_DEF_SG_TABLESIZE = 128,
+	SRPT_DEF_SG_PER_WQE = 16,
+
+	MIN_SRPT_SQ_SIZE = 16,
+	DEF_SRPT_SQ_SIZE = 4096,
+	SRPT_RQ_SIZE = 128,
+	MIN_SRPT_SRQ_SIZE = 4,
+	DEFAULT_SRPT_SRQ_SIZE = 4095,
+	MAX_SRPT_SRQ_SIZE = 65535,
+
+	MIN_MAX_REQ_SIZE = 996,
+	DEFAULT_MAX_REQ_SIZE
+		= sizeof(struct srp_cmd)/*48*/
+		+ sizeof(struct srp_indirect_buf)/*20*/
+		+ 128 * sizeof(struct srp_direct_buf)/*16*/,
+
+	MIN_MAX_RSP_SIZE = sizeof(struct srp_rsp)/*36*/ + 4,
+	DEFAULT_MAX_RSP_SIZE = 256, /* leaves 220 bytes for sense data */
+
+	DEFAULT_MAX_RDMA_SIZE = 65536,
+};
+
+static inline u64 encode_wr_id(u8 opcode, u32 idx)
+{ return ((u64)opcode << 32) | idx; }
+static inline u8 opcode_from_wr_id(u64 wr_id)
+{ return wr_id >> 32; }
+static inline u32 idx_from_wr_id(u64 wr_id)
+{ return (u32)wr_id; }
+
+struct rdma_iu {
+	u64		raddr;
+	u32		rkey;
+	struct ib_sge	*sge;
+	u32		sge_cnt;
+	int		mem_id;
+};
+
+/**
+ * enum srpt_command_state - SCSI command state managed by SRPT.
+ * @SRPT_STATE_NEW:           New command arrived and is being processed.
+ * @SRPT_STATE_NEED_DATA:     Processing a write or bidir command and waiting
+ *                            for data arrival.
+ * @SRPT_STATE_DATA_IN:       Data for the write or bidir command arrived and is
+ *                            being processed.
+ * @SRPT_STATE_CMD_RSP_SENT:  SRP_RSP for SRP_CMD has been sent.
+ * @SRPT_STATE_MGMT:          Processing a SCSI task management command.
+ * @SRPT_STATE_MGMT_RSP_SENT: SRP_RSP for SRP_TSK_MGMT has been sent.
+ * @SRPT_STATE_DONE:          Command processing finished successfully, command
+ *                            processing has been aborted or command processing
+ *                            failed.
+ */
+enum srpt_command_state {
+	SRPT_STATE_NEW		 = 0,
+	SRPT_STATE_NEED_DATA	 = 1,
+	SRPT_STATE_DATA_IN	 = 2,
+	SRPT_STATE_CMD_RSP_SENT	 = 3,
+	SRPT_STATE_MGMT		 = 4,
+	SRPT_STATE_MGMT_RSP_SENT = 5,
+	SRPT_STATE_DONE		 = 6,
+};
+
+/**
+ * struct srpt_ioctx - Shared SRPT I/O context information.
+ * @buf:   Pointer to the buffer.
+ * @dma:   DMA address of the buffer.
+ * @index: Index of the I/O context in its ioctx_ring array.
+ */
+struct srpt_ioctx {
+	void			*buf;
+	dma_addr_t		dma;
+	uint32_t		index;
+};
+
+/**
+ * struct srpt_recv_ioctx - SRPT receive I/O context.
+ * @ioctx:     See above.
+ * @wait_list: Node for insertion in srpt_rdma_ch.cmd_wait_list.
+ */
+struct srpt_recv_ioctx {
+	struct srpt_ioctx	ioctx;
+	struct list_head	wait_list;
+};
+
+/**
+ * struct srpt_send_ioctx - SRPT send I/O context.
+ * @ioctx:       See above.
+ * @ch:          Channel pointer.
+ * @free_list:   Node in srpt_rdma_ch.free_list.
+ * @n_rbuf:      Number of data buffers in the received SRP command.
+ * @rbufs:       Pointer to SRP data buffer array.
+ * @single_rbuf: SRP data buffer if the command has only a single buffer.
+ * @sg:          Pointer to sg-list associated with this I/O context.
+ * @sg_cnt:      SG-list size.
+ * @mapped_sg_count: ib_dma_map_sg() return value.
+ * @n_rdma_ius:  Number of elements in the rdma_ius array.
+ * @rdma_ius:    Array with information about the RDMA mapping.
+ * @tag:         Tag of the received SRP information unit.
+ * @spinlock:    Protects 'state'.
+ * @state:       I/O context state.
+ * @cmd:         Target core command data structure.
+ * @sense_data:  SCSI sense data.
+ */
+struct srpt_send_ioctx {
+	struct srpt_ioctx	ioctx;
+	struct srpt_rdma_ch	*ch;
+	struct kref		 kref;
+	struct rdma_iu		*rdma_ius;
+	struct srp_direct_buf	*rbufs;
+	struct srp_direct_buf	single_rbuf;
+	struct scatterlist	*sg;
+	struct list_head	free_list;
+	spinlock_t		spinlock;
+	enum srpt_command_state	state;
+	struct se_cmd		cmd;
+	struct completion	tx_done;
+	u64			tag;
+	int			sg_cnt;
+	int			mapped_sg_count;
+	u16			n_rdma_ius;
+	u8			n_rdma;
+	u8			n_rbuf;
+	bool			queue_status_only;
+	u8			sense_data[SCSI_SENSE_BUFFERSIZE];
+};
+
+/**
+ * enum rdma_ch_state - SRP channel state.
+ * @CH_CONNECTING:	 QP is in RTR state; waiting for RTU.
+ * @CH_LIVE:		 QP is in RTS state.
+ * @CH_DISCONNECTING:    DREQ has been received; waiting for DREP
+ *                       or DREQ has been send and waiting for DREP
+ *                       or .
+ * @CH_DRAINING:	 QP is in ERR state; waiting for last WQE event.
+ * @CH_RELEASING:	 Last WQE event has been received; releasing resources.
+ */
+enum rdma_ch_state {
+	CH_CONNECTING,
+	CH_LIVE,
+	CH_DISCONNECTING,
+	CH_DRAINING,
+	CH_RELEASING
+};
+
+/**
+ * struct srpt_rdma_ch - RDMA channel.
+ * @wait_queue:    Allows the kernel thread to wait for more work.
+ * @thread:        Kernel thread that processes the IB queues associated with
+ *                 the channel.
+ * @cm_id:         IB CM ID associated with the channel.
+ * @qp:            IB queue pair used for communicating over this channel.
+ * @cq:            IB completion queue for this channel.
+ * @rq_size:       IB receive queue size.
+ * @sq_wr_avail:   number of work requests available in the send queue.
+ * @sport:         pointer to the information of the HCA port used by this
+ *                 channel.
+ * @i_port_id:     128-bit initiator port identifier copied from SRP_LOGIN_REQ.
+ * @t_port_id:     128-bit target port identifier copied from SRP_LOGIN_REQ.
+ * @max_ti_iu_len: maximum target-to-initiator information unit length.
+ * @req_lim:       request limit: maximum number of requests that may be sent
+ *                 by the initiator without having received a response.
+ * @req_lim_delta: Number of credits not yet sent back to the initiator.
+ * @spinlock:      Protects free_list and state.
+ * @free_list:     Head of list with free send I/O contexts.
+ * @state:         channel state. See also enum rdma_ch_state.
+ * @ioctx_ring:    Send ring.
+ * @wc:            IB work completion array for srpt_process_completion().
+ * @list:          Node for insertion in the srpt_device.rch_list list.
+ * @cmd_wait_list: List of SCSI commands that arrived before the RTU event. This
+ *                 list contains struct srpt_ioctx elements and is protected
+ *                 against concurrent modification by the cm_id spinlock.
+ * @sess:          Session information associated with this SRP channel.
+ * @sess_name:     Session name.
+ * @release_work:  Allows scheduling of srpt_release_channel().
+ * @release_done:  Enables waiting for srpt_release_channel() completion.
+ */
+struct srpt_rdma_ch {
+	wait_queue_head_t	wait_queue;
+	struct task_struct	*thread;
+	struct ib_cm_id		*cm_id;
+	struct ib_qp		*qp;
+	struct ib_cq		*cq;
+	int			rq_size;
+	atomic_t		sq_wr_avail;
+	struct srpt_port	*sport;
+	u8			i_port_id[16];
+	u8			t_port_id[16];
+	int			max_ti_iu_len;
+	atomic_t		req_lim;
+	atomic_t		req_lim_delta;
+	spinlock_t		spinlock;
+	struct list_head	free_list;
+	enum rdma_ch_state	state;
+	struct srpt_send_ioctx	**ioctx_ring;
+	struct ib_wc		wc[16];
+	struct list_head	list;
+	struct list_head	cmd_wait_list;
+	struct se_session	*sess;
+	u8			sess_name[36];
+	struct work_struct	release_work;
+	struct completion	*release_done;
+};
+
+/**
+ * struct srpt_port - Information associated by SRPT with a single IB port.
+ * @sdev:      backpointer to the HCA information.
+ * @mad_agent: per-port management datagram processing information.
+ * @enabled:   Whether or not this target port is enabled.
+ * @port_guid: ASCII representation of Port GUID
+ * @port:      one-based port number.
+ * @sm_lid:    cached value of the port's sm_lid.
+ * @lid:       cached value of the port's lid.
+ * @gid:       cached value of the port's gid.
+ * @port_acl_lock spinlock for port_acl_list:
+ * @work:      work structure for refreshing the aforementioned cached values.
+ * @port_tpg_1 Target portal group = 1 data.
+ * @port_wwn:  Target core WWN data.
+ * @port_acl_list: Head of the list with all node ACLs for this port.
+ */
+struct srpt_port {
+	struct srpt_device	*sdev;
+	struct ib_mad_agent	*mad_agent;
+	bool			enabled;
+	u8			port_guid[64];
+	u8			port;
+	u16			sm_lid;
+	u16			lid;
+	union ib_gid		gid;
+	spinlock_t		port_acl_lock;
+	struct work_struct	work;
+	struct se_portal_group	port_tpg_1;
+	struct se_wwn		port_wwn;
+	struct list_head	port_acl_list;
+};
+
+/**
+ * struct srpt_device - Information associated by SRPT with a single HCA.
+ * @device:        Backpointer to the struct ib_device managed by the IB core.
+ * @pd:            IB protection domain.
+ * @mr:            L_Key (local key) with write access to all local memory.
+ * @srq:           Per-HCA SRQ (shared receive queue).
+ * @cm_id:         Connection identifier.
+ * @dev_attr:      Attributes of the InfiniBand device as obtained during the
+ *                 ib_client.add() callback.
+ * @srq_size:      SRQ size.
+ * @ioctx_ring:    Per-HCA SRQ.
+ * @rch_list:      Per-device channel list -- see also srpt_rdma_ch.list.
+ * @ch_releaseQ:   Enables waiting for removal from rch_list.
+ * @spinlock:      Protects rch_list and tpg.
+ * @port:          Information about the ports owned by this HCA.
+ * @event_handler: Per-HCA asynchronous IB event handler.
+ * @list:          Node in srpt_dev_list.
+ */
+struct srpt_device {
+	struct ib_device	*device;
+	struct ib_pd		*pd;
+	struct ib_mr		*mr;
+	struct ib_srq		*srq;
+	struct ib_cm_id		*cm_id;
+	struct ib_device_attr	dev_attr;
+	int			srq_size;
+	struct srpt_recv_ioctx	**ioctx_ring;
+	struct list_head	rch_list;
+	wait_queue_head_t	ch_releaseQ;
+	spinlock_t		spinlock;
+	struct srpt_port	port[2];
+	struct ib_event_handler	event_handler;
+	struct list_head	list;
+};
+
+/**
+ * struct srpt_node_acl - Per-initiator ACL data (managed via configfs).
+ * @i_port_id: 128-bit SRP initiator port ID.
+ * @sport:     port information.
+ * @nacl:      Target core node ACL information.
+ * @list:      Element of the per-HCA ACL list.
+ */
+struct srpt_node_acl {
+	u8			i_port_id[16];
+	struct srpt_port	*sport;
+	struct se_node_acl	nacl;
+	struct list_head	list;
+};
+
+/*
+ * SRP-releated SCSI persistent reservation definitions.
+ *
+ * See also SPC4r28, section 7.6.1 (Protocol specific parameters introduction).
+ * See also SPC4r28, section 7.6.4.5 (TransportID for initiator ports using
+ * SCSI over an RDMA interface).
+ */
+
+enum {
+	SCSI_TRANSPORTID_PROTOCOLID_SRP	= 4,
+};
+
+struct spc_rdma_transport_id {
+	uint8_t protocol_identifier;
+	uint8_t reserved[7];
+	uint8_t i_port_id[16];
+};
+
+#endif				/* IB_SRPT_H */
-- 
1.7.5.1

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