iser-target: Add iSCSI Extensions for RDMA (iSER) target driver

This patch adds support for iSCSI Extensions for RDMA target mode,
and includes CQ pooling per isert_device context distributed across
multiple active iser target sessions.

It also uses cmwq process context for RX / TX ib_post_cq() polling
via isert_cq_desc->cq_[rx,tx]_work invoked by isert_cq_[rx,tx]_callback()
hardIRQ context callbacks.

v5 changes:

- Use ISER_RECV_DATA_SEG_LEN instead of hardcoded value in ISER_RX_PAD_SIZE (Or)
- Fix make W=1 warnings (Or)
- Add missing depends on NET && INFINIBAND_ADDR_TRANS in Kconfig (Randy + Or)
- Make isert_device_find_by_ib_dev() return proper ERR_PTR (Wei Yongjun)
- Properly setup iscsi_np->np_sockaddr in isert_setup_np() (Shlomi + nab)
- Add special case for early ISCSI_OP_SCSI_CMD exception handling (nab)

v4 changes:
- Mark isert_cq_rx_work as static (Or)
- Drop unnecessary ib_dma_sync_single_for_cpu + ib_dma_sync_single_for_device
  calls for isert_cmd->sense_buf_dma from isert_put_response (Or)
- Use 12288 for ISER_RX_PAD_SIZE base to save extra page per
  struct iser_rx_desc (Or + nab)
- Drop now unnecessary isert_rx_desc usage, and convert RX users to
  iser_rx_desc (Or + nab)
- Move isert_[alloc,free]_rx_descriptors() ahead of
  isert_create_device_ib_res() usage (nab)
- Mark isert_cq_[rx,tx]_callback() + prototypes as static
- Fix 'warning: 'ret' may be used uninitialized' warning for
  isert_create_device_ib_res on powerpc allmodconfig (fengguang + nab)
- Fix 'warning: 'ret' may be used uninitialized' warning for
  isert_connect_request on i386 allyesconfig (fengguang + nab)
- Fix pr_debug conversion specification in isert_rx_completion()
  (fengguang + nab)
- Drop unnecessary isert_conn->conn_cm_id != NULL check in
  isert_connect_release causing the build warning:
  "variable dereferenced before check 'isert_conn->conn_cm_id'"
- Fix isert_lid + isert_np leak in isert_setup_np failure path
- Add isert_conn->conn_wait_comp_err usage in isert_free_conn()
  for isert_cq_comp_err completion path
- Add isert_conn->logout_posted bit to determine decrement of
  isert_conn->post_send_buf_count from logout response completion
- Always set ISER_CONN_DOWN from isert_disconnect_work() callback

v3 changes:

- Convert to use per isert_cq_desc->cq_[rx,tx]_work + drop tasklets (Or + nab)
- Move IB_EVENT_QP_LAST_WQE_REACHED warn into correct
  isert_qp_event_callback (Or)
- Drop unnecessary IB_ACCESS_REMOTE_* access flag usage in
  isert_create_device_ib_res (Or)
- Add common isert_init_send_wr(), and convert isert_put_* calls (Or)
- Move to verbs+core logic to single ib_isert.[c,h]  (Or + nab)
- Add kmem_cache isert_cmd_cache usage for descriptor allocation (nab)
- Move common ib_post_send() logic used by isert_put_*() to
  isert_post_response() (nab)
- Add isert_put_reject call in isert_response_queue() for posting
  ISCSI_REJECT response. (nab)
- Add ISTATE_SEND_REJECT checking in isert_do_control_comp. (nab)

v2 changes:

- Drop unused ISERT_ADDR_ROUTE_TIMEOUT define
- Add rdma_notify() call for IB_EVENT_COMM_EST in isert_qp_event_callback()
- Make isert_query_device() less verbose
- Drop unused RDMA_CM_EVENT_ADDR_ERROR and RDMA_CM_EVENT_ROUTE_ERROR
  cases from isert_cma_handler()
- Drop unused rdma/ib_fmr_pool.h include
- Update isert_conn_setup_qp() to assign cq based upon least used
- Add isert_create_device_ib_res() to setup PD, CQs and MRs for each
  underlying struct ib_device, instead of using per isert_conn resources.
- Add isert_free_device_ib_res() to release PD, CQs and MRs for each
  underlying struct ib_device.
- Add isert_device_find_by_ib_dev()
- Change isert_connect_request() to drop PD, CQs and MRs allocation,
  and use isert_device_find_by_ib_dev() instead.
- Add isert_device_try_release()
- Change isert_connect_release() to decrement cq_active_qps, and drop
  PD, CQs and MRs resource release.
- Update isert_connect_release() to call isert_device_try_release()
- Make isert_create_device_ib_res() determine device->cqs_used based
  upon num_online_cpus()
- Drop misleading isert_dump_ib_wc() usage
- Drop unused rdma/ib_fmr_pool.h include
- Use proper xfer_len for login PDUs in isert_rx_completion()
- Add isert_release_cmd() usage
- Change isert_alloc_cmd() to setup iscsi_cmd.release_cmd() pointer
- Change isert_put_cmd() to perform per iscsi_opcode specific release
  logic
- Add isert_unmap_cmd() call for ISCSI_OP_SCSI_CMD from isert_put_cmd()
- Change isert_send_completion() to call
  atomic_dec(&isert_conn->post_send_buf_count)
  based upon per iscsi_opcode logic
- Drop ISTATE_REMOVE processing from isert_immediate_queue()
- Drop ISTATE_SEND_DATAIN processing from isert_response_queue()
- Drop ISTATE_SEND_STATUS processing from isert_response_queue()
- Drop iscsit_transport->iscsit_unmap_cmd() and ->iscsit_free_cmd()
- Convert iser_cq_tx_tasklet() to use struct isert_cq_desc pooling logic
- Convert isert_cq_tx_callback() to use struct isert_cq_desc pooling
  logic
- Convert iser_cq_rx_tasklet() to use struct isert_cq_desc pooling logic
- Convert isert_cq_rx_callback() to use struct isert_cq_desc pooling
  logic
- Add explict iscsit_stop_dataout_timer() call to
  isert_do_rdma_read_comp()
- Use isert_get_dataout() for iscsit_transport->iscsit_get_dataout()
  caller
- Drop ISTATE_SEND_R2T processing from isert_immediate_queue()
- Drop unused rdma/ib_fmr_pool.h include
- Drop isert_cmd->cmd_kref in favor of se_cmd->cmd_kref usage
- Add struct isert_device in order to support multiple EQs + CQ pooling
- Add struct isert_cq_desc
- Drop tasklets and cqs from isert_conn
- Bump ISERT_MAX_CQ to 64
- Various minor checkpatch fixes

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

7 files changed, 2475 insertions, 0 deletions

diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig
index a0f29c1d03bc..c85b56c28099 100644
--- a/drivers/infiniband/Kconfig
+++ b/drivers/infiniband/Kconfig
@@ -59,5 +59,6 @@ source "drivers/infiniband/ulp/srp/Kconfig"
 source "drivers/infiniband/ulp/srpt/Kconfig"
 
 source "drivers/infiniband/ulp/iser/Kconfig"
+source "drivers/infiniband/ulp/isert/Kconfig"
 
 endif # INFINIBAND
diff --git a/drivers/infiniband/Makefile b/drivers/infiniband/Makefile
index bf846a14b9d3..b126fefe0b1c 100644
--- a/drivers/infiniband/Makefile
+++ b/drivers/infiniband/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_INFINIBAND_IPOIB)		+= ulp/ipoib/
 obj-$(CONFIG_INFINIBAND_SRP)		+= ulp/srp/
 obj-$(CONFIG_INFINIBAND_SRPT)		+= ulp/srpt/
 obj-$(CONFIG_INFINIBAND_ISER)		+= ulp/iser/
+obj-$(CONFIG_INFINIBAND_ISERT)		+= ulp/isert/
diff --git a/drivers/infiniband/ulp/isert/Kconfig b/drivers/infiniband/ulp/isert/Kconfig
new file mode 100644
index 000000000000..ce3fd32167dc
--- /dev/null
+++ b/drivers/infiniband/ulp/isert/Kconfig
@@ -0,0 +1,5 @@
+config INFINIBAND_ISERT
+	tristate "iSCSI Extentions for RDMA (iSER) target support"
+	depends on INET && INFINIBAND_ADDR_TRANS && TARGET_CORE && ISCSI_TARGET
+	---help---
+	Support for iSCSI Extentions for RDMA (iSER) Target on Infiniband fabrics.
diff --git a/drivers/infiniband/ulp/isert/Makefile b/drivers/infiniband/ulp/isert/Makefile
new file mode 100644
index 000000000000..c8bf2421f5bc
--- /dev/null
+++ b/drivers/infiniband/ulp/isert/Makefile
@@ -0,0 +1,2 @@
+ccflags-y		:= -Idrivers/target -Idrivers/target/iscsi
+obj-$(CONFIG_INFINIBAND_ISERT)	+= ib_isert.o
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
new file mode 100644
index 000000000000..41712f096515
--- /dev/null
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -0,0 +1,2281 @@
+/*******************************************************************************
+ * This file contains iSCSI extentions for RDMA (iSER) Verbs
+ *
+ * (c) Copyright 2013 RisingTide Systems LLC.
+ *
+ * Nicholas A. Bellinger <nab@linux-iscsi.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ ****************************************************************************/
+
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <target/target_core_base.h>
+#include <target/target_core_fabric.h>
+#include <target/iscsi/iscsi_transport.h>
+
+#include "isert_proto.h"
+#include "ib_isert.h"
+
+#define	ISERT_MAX_CONN		8
+#define ISER_MAX_RX_CQ_LEN	(ISERT_QP_MAX_RECV_DTOS * ISERT_MAX_CONN)
+#define ISER_MAX_TX_CQ_LEN	(ISERT_QP_MAX_REQ_DTOS  * ISERT_MAX_CONN)
+
+static DEFINE_MUTEX(device_list_mutex);
+static LIST_HEAD(device_list);
+static struct workqueue_struct *isert_rx_wq;
+static struct workqueue_struct *isert_comp_wq;
+static struct kmem_cache *isert_cmd_cache;
+
+static void
+isert_qp_event_callback(struct ib_event *e, void *context)
+{
+	struct isert_conn *isert_conn = (struct isert_conn *)context;
+
+	pr_err("isert_qp_event_callback event: %d\n", e->event);
+	switch (e->event) {
+	case IB_EVENT_COMM_EST:
+		rdma_notify(isert_conn->conn_cm_id, IB_EVENT_COMM_EST);
+		break;
+	case IB_EVENT_QP_LAST_WQE_REACHED:
+		pr_warn("Reached TX IB_EVENT_QP_LAST_WQE_REACHED:\n");
+		break;
+	default:
+		break;
+	}
+}
+
+static int
+isert_query_device(struct ib_device *ib_dev, struct ib_device_attr *devattr)
+{
+	int ret;
+
+	ret = ib_query_device(ib_dev, devattr);
+	if (ret) {
+		pr_err("ib_query_device() failed: %d\n", ret);
+		return ret;
+	}
+	pr_debug("devattr->max_sge: %d\n", devattr->max_sge);
+	pr_debug("devattr->max_sge_rd: %d\n", devattr->max_sge_rd);
+
+	return 0;
+}
+
+static int
+isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
+{
+	struct isert_device *device = isert_conn->conn_device;
+	struct ib_qp_init_attr attr;
+	struct ib_device_attr devattr;
+	int ret, index, min_index = 0;
+
+	memset(&devattr, 0, sizeof(struct ib_device_attr));
+	ret = isert_query_device(cma_id->device, &devattr);
+	if (ret)
+		return ret;
+
+	mutex_lock(&device_list_mutex);
+	for (index = 0; index < device->cqs_used; index++)
+		if (device->cq_active_qps[index] <
+		    device->cq_active_qps[min_index])
+			min_index = index;
+	device->cq_active_qps[min_index]++;
+	pr_debug("isert_conn_setup_qp: Using min_index: %d\n", min_index);
+	mutex_unlock(&device_list_mutex);
+
+	memset(&attr, 0, sizeof(struct ib_qp_init_attr));
+	attr.event_handler = isert_qp_event_callback;
+	attr.qp_context = isert_conn;
+	attr.send_cq = device->dev_tx_cq[min_index];
+	attr.recv_cq = device->dev_rx_cq[min_index];
+	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS;
+	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS;
+	/*
+	 * FIXME: Use devattr.max_sge - 2 for max_send_sge as
+	 * work-around for RDMA_READ..
+	 */
+	attr.cap.max_send_sge = devattr.max_sge - 2;
+	isert_conn->max_sge = attr.cap.max_send_sge;
+
+	attr.cap.max_recv_sge = 1;
+	attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+	attr.qp_type = IB_QPT_RC;
+
+	pr_debug("isert_conn_setup_qp cma_id->device: %p\n",
+		 cma_id->device);
+	pr_debug("isert_conn_setup_qp conn_pd->device: %p\n",
+		 isert_conn->conn_pd->device);
+
+	ret = rdma_create_qp(cma_id, isert_conn->conn_pd, &attr);
+	if (ret) {
+		pr_err("rdma_create_qp failed for cma_id %d\n", ret);
+		return ret;
+	}
+	isert_conn->conn_qp = cma_id->qp;
+	pr_debug("rdma_create_qp() returned success >>>>>>>>>>>>>>>>>>>>>>>>>.\n");
+
+	return 0;
+}
+
+static void
+isert_cq_event_callback(struct ib_event *e, void *context)
+{
+	pr_debug("isert_cq_event_callback event: %d\n", e->event);
+}
+
+static int
+isert_alloc_rx_descriptors(struct isert_conn *isert_conn)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct iser_rx_desc *rx_desc;
+	struct ib_sge *rx_sg;
+	u64 dma_addr;
+	int i, j;
+
+	isert_conn->conn_rx_descs = kzalloc(ISERT_QP_MAX_RECV_DTOS *
+				sizeof(struct iser_rx_desc), GFP_KERNEL);
+	if (!isert_conn->conn_rx_descs)
+		goto fail;
+
+	rx_desc = isert_conn->conn_rx_descs;
+
+	for (i = 0; i < ISERT_QP_MAX_RECV_DTOS; i++, rx_desc++)  {
+		dma_addr = ib_dma_map_single(ib_dev, (void *)rx_desc,
+					ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+		if (ib_dma_mapping_error(ib_dev, dma_addr))
+			goto dma_map_fail;
+
+		rx_desc->dma_addr = dma_addr;
+
+		rx_sg = &rx_desc->rx_sg;
+		rx_sg->addr = rx_desc->dma_addr;
+		rx_sg->length = ISER_RX_PAYLOAD_SIZE;
+		rx_sg->lkey = isert_conn->conn_mr->lkey;
+	}
+
+	isert_conn->conn_rx_desc_head = 0;
+	return 0;
+
+dma_map_fail:
+	rx_desc = isert_conn->conn_rx_descs;
+	for (j = 0; j < i; j++, rx_desc++) {
+		ib_dma_unmap_single(ib_dev, rx_desc->dma_addr,
+				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+	}
+	kfree(isert_conn->conn_rx_descs);
+	isert_conn->conn_rx_descs = NULL;
+fail:
+	return -ENOMEM;
+}
+
+static void
+isert_free_rx_descriptors(struct isert_conn *isert_conn)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct iser_rx_desc *rx_desc;
+	int i;
+
+	if (!isert_conn->conn_rx_descs)
+		return;
+
+	rx_desc = isert_conn->conn_rx_descs;
+	for (i = 0; i < ISERT_QP_MAX_RECV_DTOS; i++, rx_desc++)  {
+		ib_dma_unmap_single(ib_dev, rx_desc->dma_addr,
+				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+	}
+
+	kfree(isert_conn->conn_rx_descs);
+	isert_conn->conn_rx_descs = NULL;
+}
+
+static void isert_cq_tx_callback(struct ib_cq *, void *);
+static void isert_cq_rx_callback(struct ib_cq *, void *);
+
+static int
+isert_create_device_ib_res(struct isert_device *device)
+{
+	struct ib_device *ib_dev = device->ib_device;
+	struct isert_cq_desc *cq_desc;
+	int ret = 0, i, j;
+
+	device->cqs_used = min_t(int, num_online_cpus(),
+				 device->ib_device->num_comp_vectors);
+	device->cqs_used = min(ISERT_MAX_CQ, device->cqs_used);
+	pr_debug("Using %d CQs, device %s supports %d vectors\n",
+		 device->cqs_used, device->ib_device->name,
+		 device->ib_device->num_comp_vectors);
+	device->cq_desc = kzalloc(sizeof(struct isert_cq_desc) *
+				device->cqs_used, GFP_KERNEL);
+	if (!device->cq_desc) {
+		pr_err("Unable to allocate device->cq_desc\n");
+		return -ENOMEM;
+	}
+	cq_desc = device->cq_desc;
+
+	device->dev_pd = ib_alloc_pd(ib_dev);
+	if (IS_ERR(device->dev_pd)) {
+		ret = PTR_ERR(device->dev_pd);
+		pr_err("ib_alloc_pd failed for dev_pd: %d\n", ret);
+		goto out_cq_desc;
+	}
+
+	for (i = 0; i < device->cqs_used; i++) {
+		cq_desc[i].device = device;
+		cq_desc[i].cq_index = i;
+
+		device->dev_rx_cq[i] = ib_create_cq(device->ib_device,
+						isert_cq_rx_callback,
+						isert_cq_event_callback,
+						(void *)&cq_desc[i],
+						ISER_MAX_RX_CQ_LEN, i);
+		if (IS_ERR(device->dev_rx_cq[i]))
+			goto out_cq;
+
+		device->dev_tx_cq[i] = ib_create_cq(device->ib_device,
+						isert_cq_tx_callback,
+						isert_cq_event_callback,
+						(void *)&cq_desc[i],
+						ISER_MAX_TX_CQ_LEN, i);
+		if (IS_ERR(device->dev_tx_cq[i]))
+			goto out_cq;
+
+		if (ib_req_notify_cq(device->dev_rx_cq[i], IB_CQ_NEXT_COMP))
+			goto out_cq;
+
+		if (ib_req_notify_cq(device->dev_tx_cq[i], IB_CQ_NEXT_COMP))
+			goto out_cq;
+	}
+
+	device->dev_mr = ib_get_dma_mr(device->dev_pd, IB_ACCESS_LOCAL_WRITE);
+	if (IS_ERR(device->dev_mr)) {
+		ret = PTR_ERR(device->dev_mr);
+		pr_err("ib_get_dma_mr failed for dev_mr: %d\n", ret);
+		goto out_cq;
+	}
+
+	return 0;
+
+out_cq:
+	for (j = 0; j < i; j++) {
+		cq_desc = &device->cq_desc[j];
+
+		if (device->dev_rx_cq[j]) {
+			cancel_work_sync(&cq_desc->cq_rx_work);
+			ib_destroy_cq(device->dev_rx_cq[j]);
+		}
+		if (device->dev_tx_cq[j]) {
+			cancel_work_sync(&cq_desc->cq_tx_work);
+			ib_destroy_cq(device->dev_tx_cq[j]);
+		}
+	}
+	ib_dealloc_pd(device->dev_pd);
+
+out_cq_desc:
+	kfree(device->cq_desc);
+
+	return ret;
+}
+
+static void
+isert_free_device_ib_res(struct isert_device *device)
+{
+	struct isert_cq_desc *cq_desc;
+	int i;
+
+	for (i = 0; i < device->cqs_used; i++) {
+		cq_desc = &device->cq_desc[i];
+
+		cancel_work_sync(&cq_desc->cq_rx_work);
+		cancel_work_sync(&cq_desc->cq_tx_work);
+		ib_destroy_cq(device->dev_rx_cq[i]);
+		ib_destroy_cq(device->dev_tx_cq[i]);
+		device->dev_rx_cq[i] = NULL;
+		device->dev_tx_cq[i] = NULL;
+	}
+
+	ib_dereg_mr(device->dev_mr);
+	ib_dealloc_pd(device->dev_pd);
+	kfree(device->cq_desc);
+}
+
+static void
+isert_device_try_release(struct isert_device *device)
+{
+	mutex_lock(&device_list_mutex);
+	device->refcount--;
+	if (!device->refcount) {
+		isert_free_device_ib_res(device);
+		list_del(&device->dev_node);
+		kfree(device);
+	}
+	mutex_unlock(&device_list_mutex);
+}
+
+static struct isert_device *
+isert_device_find_by_ib_dev(struct rdma_cm_id *cma_id)
+{
+	struct isert_device *device;
+	int ret;
+
+	mutex_lock(&device_list_mutex);
+	list_for_each_entry(device, &device_list, dev_node) {
+		if (device->ib_device->node_guid == cma_id->device->node_guid) {
+			device->refcount++;
+			mutex_unlock(&device_list_mutex);
+			return device;
+		}
+	}
+
+	device = kzalloc(sizeof(struct isert_device), GFP_KERNEL);
+	if (!device) {
+		mutex_unlock(&device_list_mutex);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	INIT_LIST_HEAD(&device->dev_node);
+
+	device->ib_device = cma_id->device;
+	ret = isert_create_device_ib_res(device);
+	if (ret) {
+		kfree(device);
+		mutex_unlock(&device_list_mutex);
+		return ERR_PTR(ret);
+	}
+
+	device->refcount++;
+	list_add_tail(&device->dev_node, &device_list);
+	mutex_unlock(&device_list_mutex);
+
+	return device;
+}
+
+static int
+isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
+{
+	struct iscsi_np *np = cma_id->context;
+	struct isert_np *isert_np = np->np_context;
+	struct isert_conn *isert_conn;
+	struct isert_device *device;
+	struct ib_device *ib_dev = cma_id->device;
+	int ret = 0;
+
+	pr_debug("Entering isert_connect_request cma_id: %p, context: %p\n",
+		 cma_id, cma_id->context);
+
+	isert_conn = kzalloc(sizeof(struct isert_conn), GFP_KERNEL);
+	if (!isert_conn) {
+		pr_err("Unable to allocate isert_conn\n");
+		return -ENOMEM;
+	}
+	isert_conn->state = ISER_CONN_INIT;
+	INIT_LIST_HEAD(&isert_conn->conn_accept_node);
+	init_completion(&isert_conn->conn_login_comp);
+	init_waitqueue_head(&isert_conn->conn_wait);
+	init_waitqueue_head(&isert_conn->conn_wait_comp_err);
+	kref_init(&isert_conn->conn_kref);
+	kref_get(&isert_conn->conn_kref);
+
+	cma_id->context = isert_conn;
+	isert_conn->conn_cm_id = cma_id;
+	isert_conn->responder_resources = event->param.conn.responder_resources;
+	isert_conn->initiator_depth = event->param.conn.initiator_depth;
+	pr_debug("Using responder_resources: %u initiator_depth: %u\n",
+		 isert_conn->responder_resources, isert_conn->initiator_depth);
+
+	isert_conn->login_buf = kzalloc(ISCSI_DEF_MAX_RECV_SEG_LEN +
+					ISER_RX_LOGIN_SIZE, GFP_KERNEL);
+	if (!isert_conn->login_buf) {
+		pr_err("Unable to allocate isert_conn->login_buf\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	isert_conn->login_req_buf = isert_conn->login_buf;
+	isert_conn->login_rsp_buf = isert_conn->login_buf +
+				    ISCSI_DEF_MAX_RECV_SEG_LEN;
+	pr_debug("Set login_buf: %p login_req_buf: %p login_rsp_buf: %p\n",
+		 isert_conn->login_buf, isert_conn->login_req_buf,
+		 isert_conn->login_rsp_buf);
+
+	isert_conn->login_req_dma = ib_dma_map_single(ib_dev,
+				(void *)isert_conn->login_req_buf,
+				ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_FROM_DEVICE);
+
+	ret = ib_dma_mapping_error(ib_dev, isert_conn->login_req_dma);
+	if (ret) {
+		pr_err("ib_dma_mapping_error failed for login_req_dma: %d\n",
+		       ret);
+		isert_conn->login_req_dma = 0;
+		goto out_login_buf;
+	}
+
+	isert_conn->login_rsp_dma = ib_dma_map_single(ib_dev,
+					(void *)isert_conn->login_rsp_buf,
+					ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);
+
+	ret = ib_dma_mapping_error(ib_dev, isert_conn->login_rsp_dma);
+	if (ret) {
+		pr_err("ib_dma_mapping_error failed for login_rsp_dma: %d\n",
+		       ret);
+		isert_conn->login_rsp_dma = 0;
+		goto out_req_dma_map;
+	}
+
+	device = isert_device_find_by_ib_dev(cma_id);
+	if (IS_ERR(device)) {
+		ret = PTR_ERR(device);
+		goto out_rsp_dma_map;
+	}
+
+	isert_conn->conn_device = device;
+	isert_conn->conn_pd = device->dev_pd;
+	isert_conn->conn_mr = device->dev_mr;
+
+	ret = isert_conn_setup_qp(isert_conn, cma_id);
+	if (ret)
+		goto out_conn_dev;
+
+	mutex_lock(&isert_np->np_accept_mutex);
+	list_add_tail(&isert_np->np_accept_list, &isert_conn->conn_accept_node);
+	mutex_unlock(&isert_np->np_accept_mutex);
+
+	pr_debug("isert_connect_request() waking up np_accept_wq: %p\n", np);
+	wake_up(&isert_np->np_accept_wq);
+	return 0;
+
+out_conn_dev:
+	isert_device_try_release(device);
+out_rsp_dma_map:
+	ib_dma_unmap_single(ib_dev, isert_conn->login_rsp_dma,
+			    ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);
+out_req_dma_map:
+	ib_dma_unmap_single(ib_dev, isert_conn->login_req_dma,
+			    ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_FROM_DEVICE);
+out_login_buf:
+	kfree(isert_conn->login_buf);
+out:
+	kfree(isert_conn);
+	return ret;
+}
+
+static void
+isert_connect_release(struct isert_conn *isert_conn)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct isert_device *device = isert_conn->conn_device;
+	int cq_index;
+
+	pr_debug("Entering isert_connect_release(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+
+	if (isert_conn->conn_qp) {
+		cq_index = ((struct isert_cq_desc *)
+			isert_conn->conn_qp->recv_cq->cq_context)->cq_index;
+		pr_debug("isert_connect_release: cq_index: %d\n", cq_index);
+		isert_conn->conn_device->cq_active_qps[cq_index]--;
+
+		rdma_destroy_qp(isert_conn->conn_cm_id);
+	}
+
+	isert_free_rx_descriptors(isert_conn);
+	rdma_destroy_id(isert_conn->conn_cm_id);
+
+	if (isert_conn->login_buf) {
+		ib_dma_unmap_single(ib_dev, isert_conn->login_rsp_dma,
+				    ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);
+		ib_dma_unmap_single(ib_dev, isert_conn->login_req_dma,
+				    ISCSI_DEF_MAX_RECV_SEG_LEN,
+				    DMA_FROM_DEVICE);
+		kfree(isert_conn->login_buf);
+	}
+	kfree(isert_conn);
+
+	if (device)
+		isert_device_try_release(device);
+
+	pr_debug("Leaving isert_connect_release >>>>>>>>>>>>\n");
+}
+
+static void
+isert_connected_handler(struct rdma_cm_id *cma_id)
+{
+	return;
+}
+
+static void
+isert_release_conn_kref(struct kref *kref)
+{
+	struct isert_conn *isert_conn = container_of(kref,
+				struct isert_conn, conn_kref);
+
+	pr_debug("Calling isert_connect_release for final kref %s/%d\n",
+		 current->comm, current->pid);
+
+	isert_connect_release(isert_conn);
+}
+
+static void
+isert_put_conn(struct isert_conn *isert_conn)
+{
+	kref_put(&isert_conn->conn_kref, isert_release_conn_kref);
+}
+
+static void
+isert_disconnect_work(struct work_struct *work)
+{
+	struct isert_conn *isert_conn = container_of(work,
+				struct isert_conn, conn_logout_work);
+
+	pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+
+	isert_conn->state = ISER_CONN_DOWN;
+
+	if (isert_conn->post_recv_buf_count == 0 &&
+	    atomic_read(&isert_conn->post_send_buf_count) == 0) {
+		pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");
+		wake_up(&isert_conn->conn_wait);
+	}
+
+	isert_put_conn(isert_conn);
+}
+
+static void
+isert_disconnected_handler(struct rdma_cm_id *cma_id)
+{
+	struct isert_conn *isert_conn = (struct isert_conn *)cma_id->context;
+
+	INIT_WORK(&isert_conn->conn_logout_work, isert_disconnect_work);
+	schedule_work(&isert_conn->conn_logout_work);
+}
+
+static int
+isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
+{
+	int ret = 0;
+
+	pr_debug("isert_cma_handler: event %d status %d conn %p id %p\n",
+		 event->event, event->status, cma_id->context, cma_id);
+
+	switch (event->event) {
+	case RDMA_CM_EVENT_CONNECT_REQUEST:
+		pr_debug("RDMA_CM_EVENT_CONNECT_REQUEST: >>>>>>>>>>>>>>>\n");
+		ret = isert_connect_request(cma_id, event);
+		break;
+	case RDMA_CM_EVENT_ESTABLISHED:
+		pr_debug("RDMA_CM_EVENT_ESTABLISHED >>>>>>>>>>>>>>\n");
+		isert_connected_handler(cma_id);
+		break;
+	case RDMA_CM_EVENT_DISCONNECTED:
+		pr_debug("RDMA_CM_EVENT_DISCONNECTED: >>>>>>>>>>>>>>\n");
+		isert_disconnected_handler(cma_id);
+		break;
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+		break;
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	default:
+		pr_err("Unknown RDMA CMA event: %d\n", event->event);
+		break;
+	}
+
+	if (ret != 0) {
+		pr_err("isert_cma_handler failed RDMA_CM_EVENT: 0x%08x %d\n",
+		       event->event, ret);
+		dump_stack();
+	}
+
+	return ret;
+}
+
+static int
+isert_post_recv(struct isert_conn *isert_conn, u32 count)
+{
+	struct ib_recv_wr *rx_wr, *rx_wr_failed;
+	int i, ret;
+	unsigned int rx_head = isert_conn->conn_rx_desc_head;
+	struct iser_rx_desc *rx_desc;
+
+	for (rx_wr = isert_conn->conn_rx_wr, i = 0; i < count; i++, rx_wr++) {
+		rx_desc		= &isert_conn->conn_rx_descs[rx_head];
+		rx_wr->wr_id	= (unsigned long)rx_desc;
+		rx_wr->sg_list	= &rx_desc->rx_sg;
+		rx_wr->num_sge	= 1;
+		rx_wr->next	= rx_wr + 1;
+		rx_head = (rx_head + 1) & (ISERT_QP_MAX_RECV_DTOS - 1);
+	}
+
+	rx_wr--;
+	rx_wr->next = NULL; /* mark end of work requests list */
+
+	isert_conn->post_recv_buf_count += count;
+	ret = ib_post_recv(isert_conn->conn_qp, isert_conn->conn_rx_wr,
+				&rx_wr_failed);
+	if (ret) {
+		pr_err("ib_post_recv() failed with ret: %d\n", ret);
+		isert_conn->post_recv_buf_count -= count;
+	} else {
+		pr_debug("isert_post_recv(): Posted %d RX buffers\n", count);
+		isert_conn->conn_rx_desc_head = rx_head;
+	}
+	return ret;
+}
+
+static int
+isert_post_send(struct isert_conn *isert_conn, struct iser_tx_desc *tx_desc)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct ib_send_wr send_wr, *send_wr_failed;
+	int ret;
+
+	ib_dma_sync_single_for_device(ib_dev, tx_desc->dma_addr,
+				      ISER_HEADERS_LEN, DMA_TO_DEVICE);
+
+	send_wr.next	= NULL;
+	send_wr.wr_id	= (unsigned long)tx_desc;
+	send_wr.sg_list	= tx_desc->tx_sg;
+	send_wr.num_sge	= tx_desc->num_sge;
+	send_wr.opcode	= IB_WR_SEND;
+	send_wr.send_flags = IB_SEND_SIGNALED;
+
+	atomic_inc(&isert_conn->post_send_buf_count);
+
+	ret = ib_post_send(isert_conn->conn_qp, &send_wr, &send_wr_failed);
+	if (ret) {
+		pr_err("ib_post_send() failed, ret: %d\n", ret);
+		atomic_dec(&isert_conn->post_send_buf_count);
+	}
+
+	return ret;
+}
+
+static void
+isert_create_send_desc(struct isert_conn *isert_conn,
+		       struct isert_cmd *isert_cmd,
+		       struct iser_tx_desc *tx_desc)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+
+	ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
+				   ISER_HEADERS_LEN, DMA_TO_DEVICE);
+
+	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
+	tx_desc->iser_header.flags = ISER_VER;
+
+	tx_desc->num_sge = 1;
+	tx_desc->isert_cmd = isert_cmd;
+
+	if (tx_desc->tx_sg[0].lkey != isert_conn->conn_mr->lkey) {
+		tx_desc->tx_sg[0].lkey = isert_conn->conn_mr->lkey;
+		pr_debug("tx_desc %p lkey mismatch, fixing\n", tx_desc);
+	}
+}
+
+static int
+isert_init_tx_hdrs(struct isert_conn *isert_conn,
+		   struct iser_tx_desc *tx_desc)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	u64 dma_addr;
+
+	dma_addr = ib_dma_map_single(ib_dev, (void *)tx_desc,
+			ISER_HEADERS_LEN, DMA_TO_DEVICE);
+	if (ib_dma_mapping_error(ib_dev, dma_addr)) {
+		pr_err("ib_dma_mapping_error() failed\n");
+		return -ENOMEM;
+	}
+
+	tx_desc->dma_addr = dma_addr;
+	tx_desc->tx_sg[0].addr	= tx_desc->dma_addr;
+	tx_desc->tx_sg[0].length = ISER_HEADERS_LEN;
+	tx_desc->tx_sg[0].lkey = isert_conn->conn_mr->lkey;
+
+	pr_debug("isert_init_tx_hdrs: Setup tx_sg[0].addr: 0x%llx length: %u"
+		 " lkey: 0x%08x\n", tx_desc->tx_sg[0].addr,
+		 tx_desc->tx_sg[0].length, tx_desc->tx_sg[0].lkey);
+
+	return 0;
+}
+
+static void
+isert_init_send_wr(struct isert_cmd *isert_cmd, struct ib_send_wr *send_wr)
+{
+	isert_cmd->rdma_wr.iser_ib_op = ISER_IB_SEND;
+	send_wr->wr_id = (unsigned long)&isert_cmd->tx_desc;
+	send_wr->opcode = IB_WR_SEND;
+	send_wr->send_flags = IB_SEND_SIGNALED;
+	send_wr->sg_list = &isert_cmd->tx_desc.tx_sg[0];
+	send_wr->num_sge = isert_cmd->tx_desc.num_sge;
+}
+
+static int
+isert_rdma_post_recvl(struct isert_conn *isert_conn)
+{
+	struct ib_recv_wr rx_wr, *rx_wr_fail;
+	struct ib_sge sge;
+	int ret;
+
+	memset(&sge, 0, sizeof(struct ib_sge));
+	sge.addr = isert_conn->login_req_dma;
+	sge.length = ISER_RX_LOGIN_SIZE;
+	sge.lkey = isert_conn->conn_mr->lkey;
+
+	pr_debug("Setup sge: addr: %llx length: %d 0x%08x\n",
+		sge.addr, sge.length, sge.lkey);
+
+	memset(&rx_wr, 0, sizeof(struct ib_recv_wr));
+	rx_wr.wr_id = (unsigned long)isert_conn->login_req_buf;
+	rx_wr.sg_list = &sge;
+	rx_wr.num_sge = 1;
+
+	isert_conn->post_recv_buf_count++;
+	ret = ib_post_recv(isert_conn->conn_qp, &rx_wr, &rx_wr_fail);
+	if (ret) {
+		pr_err("ib_post_recv() failed: %d\n", ret);
+		isert_conn->post_recv_buf_count--;
+	}
+
+	pr_debug("ib_post_recv(): returned success >>>>>>>>>>>>>>>>>>>>>>>>\n");
+	return ret;
+}
+
+static int
+isert_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login,
+		   u32 length)
+{
+	struct isert_conn *isert_conn = conn->context;
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct iser_tx_desc *tx_desc = &isert_conn->conn_login_tx_desc;
+	int ret;
+
+	isert_create_send_desc(isert_conn, NULL, tx_desc);
+
+	memcpy(&tx_desc->iscsi_header, &login->rsp[0],
+	       sizeof(struct iscsi_hdr));
+
+	isert_init_tx_hdrs(isert_conn, tx_desc);
+
+	if (length > 0) {
+		struct ib_sge *tx_dsg = &tx_desc->tx_sg[1];
+
+		ib_dma_sync_single_for_cpu(ib_dev, isert_conn->login_rsp_dma,
+					   length, DMA_TO_DEVICE);
+
+		memcpy(isert_conn->login_rsp_buf, login->rsp_buf, length);
+
+		ib_dma_sync_single_for_device(ib_dev, isert_conn->login_rsp_dma,
+					      length, DMA_TO_DEVICE);
+
+		tx_dsg->addr	= isert_conn->login_rsp_dma;
+		tx_dsg->length	= length;
+		tx_dsg->lkey	= isert_conn->conn_mr->lkey;
+		tx_desc->num_sge = 2;
+	}
+	if (!login->login_failed) {
+		if (login->login_complete) {
+			ret = isert_alloc_rx_descriptors(isert_conn);
+			if (ret)
+				return ret;
+
+			ret = isert_post_recv(isert_conn, ISERT_MIN_POSTED_RX);
+			if (ret)
+				return ret;
+
+			isert_conn->state = ISER_CONN_UP;
+			goto post_send;
+		}
+
+		ret = isert_rdma_post_recvl(isert_conn);
+		if (ret)
+			return ret;
+	}
+post_send:
+	ret = isert_post_send(isert_conn, tx_desc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void
+isert_rx_login_req(struct iser_rx_desc *rx_desc, int rx_buflen,
+		   struct isert_conn *isert_conn)
+{
+	struct iscsi_conn *conn = isert_conn->conn;
+	struct iscsi_login *login = conn->conn_login;
+	int size;
+
+	if (!login) {
+		pr_err("conn->conn_login is NULL\n");
+		dump_stack();
+		return;
+	}
+
+	if (login->first_request) {
+		struct iscsi_login_req *login_req =
+			(struct iscsi_login_req *)&rx_desc->iscsi_header;
+		/*
+		 * Setup the initial iscsi_login values from the leading
+		 * login request PDU.
+		 */
+		login->leading_connection = (!login_req->tsih) ? 1 : 0;
+		login->current_stage =
+			(login_req->flags & ISCSI_FLAG_LOGIN_CURRENT_STAGE_MASK)
+			 >> 2;
+		login->version_min	= login_req->min_version;
+		login->version_max	= login_req->max_version;
+		memcpy(login->isid, login_req->isid, 6);
+		login->cmd_sn		= be32_to_cpu(login_req->cmdsn);
+		login->init_task_tag	= login_req->itt;
+		login->initial_exp_statsn = be32_to_cpu(login_req->exp_statsn);
+		login->cid		= be16_to_cpu(login_req->cid);
+		login->tsih		= be16_to_cpu(login_req->tsih);
+	}
+
+	memcpy(&login->req[0], (void *)&rx_desc->iscsi_header, ISCSI_HDR_LEN);
+
+	size = min(rx_buflen, MAX_KEY_VALUE_PAIRS);
+	pr_debug("Using login payload size: %d, rx_buflen: %d MAX_KEY_VALUE_PAIRS: %d\n",
+		 size, rx_buflen, MAX_KEY_VALUE_PAIRS);
+	memcpy(login->req_buf, &rx_desc->data[0], size);
+
+	complete(&isert_conn->conn_login_comp);
+}
+
+static void
+isert_release_cmd(struct iscsi_cmd *cmd)
+{
+	struct isert_cmd *isert_cmd = container_of(cmd, struct isert_cmd,
+						   iscsi_cmd);
+
+	pr_debug("Entering isert_release_cmd %p >>>>>>>>>>>>>>>.\n", isert_cmd);
+
+	kfree(cmd->buf_ptr);
+	kfree(cmd->tmr_req);
+
+	kmem_cache_free(isert_cmd_cache, isert_cmd);
+}
+
+static struct iscsi_cmd
+*isert_alloc_cmd(struct iscsi_conn *conn, gfp_t gfp)
+{
+	struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
+	struct isert_cmd *isert_cmd;
+
+	isert_cmd = kmem_cache_zalloc(isert_cmd_cache, gfp);
+	if (!isert_cmd) {
+		pr_err("Unable to allocate isert_cmd\n");
+		return NULL;
+	}
+	isert_cmd->conn = isert_conn;
+	isert_cmd->iscsi_cmd.release_cmd = &isert_release_cmd;
+
+	return &isert_cmd->iscsi_cmd;
+}
+
+static int
+isert_handle_scsi_cmd(struct isert_conn *isert_conn,
+		      struct isert_cmd *isert_cmd, struct iser_rx_desc *rx_desc,
+		      unsigned char *buf)
+{
+	struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
+	struct iscsi_conn *conn = isert_conn->conn;
+	struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)buf;
+	struct scatterlist *sg;
+	int imm_data, imm_data_len, unsol_data, sg_nents, rc;
+	bool dump_payload = false;
+
+	rc = iscsit_setup_scsi_cmd(conn, cmd, buf);
+	if (rc < 0)
+		return rc;
+
+	imm_data = cmd->immediate_data;
+	imm_data_len = cmd->first_burst_len;
+	unsol_data = cmd->unsolicited_data;
+
+	rc = iscsit_process_scsi_cmd(conn, cmd, hdr);
+	if (rc < 0) {
+		return 0;
+	} else if (rc > 0) {
+		dump_payload = true;
+		goto sequence_cmd;
+	}
+
+	if (!imm_data)