Initial import

1 files changed, 1274 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
new file mode 100644
index 000000000..cc2dd35ff
--- /dev/null
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -0,0 +1,1274 @@
+/*
+ * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
+ * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
+ * Copyright (c) 2013-2014 Mellanox Technologies. 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.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#include "iscsi_iser.h"
+
+#define ISCSI_ISER_MAX_CONN	8
+#define ISER_MAX_RX_LEN		(ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
+#define ISER_MAX_TX_LEN		(ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)
+#define ISER_MAX_CQ_LEN		(ISER_MAX_RX_LEN + ISER_MAX_TX_LEN + \
+				 ISCSI_ISER_MAX_CONN)
+
+static int iser_cq_poll_limit = 512;
+
+static void iser_cq_tasklet_fn(unsigned long data);
+static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
+
+static void iser_cq_event_callback(struct ib_event *cause, void *context)
+{
+	iser_err("got cq event %d \n", cause->event);
+}
+
+static void iser_qp_event_callback(struct ib_event *cause, void *context)
+{
+	iser_err("got qp event %d\n",cause->event);
+}
+
+static void iser_event_handler(struct ib_event_handler *handler,
+				struct ib_event *event)
+{
+	iser_err("async event %d on device %s port %d\n", event->event,
+		event->device->name, event->element.port_num);
+}
+
+/**
+ * iser_create_device_ib_res - creates Protection Domain (PD), Completion
+ * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
+ * the adapator.
+ *
+ * returns 0 on success, -1 on failure
+ */
+static int iser_create_device_ib_res(struct iser_device *device)
+{
+	struct ib_device_attr *dev_attr = &device->dev_attr;
+	int ret, i, max_cqe;
+
+	ret = ib_query_device(device->ib_device, dev_attr);
+	if (ret) {
+		pr_warn("Query device failed for %s\n", device->ib_device->name);
+		return ret;
+	}
+
+	/* Assign function handles  - based on FMR support */
+	if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
+	    device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
+		iser_info("FMR supported, using FMR for registration\n");
+		device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
+		device->iser_free_rdma_reg_res = iser_free_fmr_pool;
+		device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
+		device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
+	} else
+	if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
+		iser_info("FastReg supported, using FastReg for registration\n");
+		device->iser_alloc_rdma_reg_res = iser_create_fastreg_pool;
+		device->iser_free_rdma_reg_res = iser_free_fastreg_pool;
+		device->iser_reg_rdma_mem = iser_reg_rdma_mem_fastreg;
+		device->iser_unreg_rdma_mem = iser_unreg_mem_fastreg;
+	} else {
+		iser_err("IB device does not support FMRs nor FastRegs, can't register memory\n");
+		return -1;
+	}
+
+	device->comps_used = min_t(int, num_online_cpus(),
+				 device->ib_device->num_comp_vectors);
+
+	device->comps = kcalloc(device->comps_used, sizeof(*device->comps),
+				GFP_KERNEL);
+	if (!device->comps)
+		goto comps_err;
+
+	max_cqe = min(ISER_MAX_CQ_LEN, dev_attr->max_cqe);
+
+	iser_info("using %d CQs, device %s supports %d vectors max_cqe %d\n",
+		  device->comps_used, device->ib_device->name,
+		  device->ib_device->num_comp_vectors, max_cqe);
+
+	device->pd = ib_alloc_pd(device->ib_device);
+	if (IS_ERR(device->pd))
+		goto pd_err;
+
+	for (i = 0; i < device->comps_used; i++) {
+		struct iser_comp *comp = &device->comps[i];
+
+		comp->device = device;
+		comp->cq = ib_create_cq(device->ib_device,
+					iser_cq_callback,
+					iser_cq_event_callback,
+					(void *)comp,
+					max_cqe, i);
+		if (IS_ERR(comp->cq)) {
+			comp->cq = NULL;
+			goto cq_err;
+		}
+
+		if (ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP))
+			goto cq_err;
+
+		tasklet_init(&comp->tasklet, iser_cq_tasklet_fn,
+			     (unsigned long)comp);
+	}
+
+	device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
+				   IB_ACCESS_REMOTE_WRITE |
+				   IB_ACCESS_REMOTE_READ);
+	if (IS_ERR(device->mr))
+		goto dma_mr_err;
+
+	INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
+				iser_event_handler);
+	if (ib_register_event_handler(&device->event_handler))
+		goto handler_err;
+
+	return 0;
+
+handler_err:
+	ib_dereg_mr(device->mr);
+dma_mr_err:
+	for (i = 0; i < device->comps_used; i++)
+		tasklet_kill(&device->comps[i].tasklet);
+cq_err:
+	for (i = 0; i < device->comps_used; i++) {
+		struct iser_comp *comp = &device->comps[i];
+
+		if (comp->cq)
+			ib_destroy_cq(comp->cq);
+	}
+	ib_dealloc_pd(device->pd);
+pd_err:
+	kfree(device->comps);
+comps_err:
+	iser_err("failed to allocate an IB resource\n");
+	return -1;
+}
+
+/**
+ * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
+ * CQ and PD created with the device associated with the adapator.
+ */
+static void iser_free_device_ib_res(struct iser_device *device)
+{
+	int i;
+	BUG_ON(device->mr == NULL);
+
+	for (i = 0; i < device->comps_used; i++) {
+		struct iser_comp *comp = &device->comps[i];
+
+		tasklet_kill(&comp->tasklet);
+		ib_destroy_cq(comp->cq);
+		comp->cq = NULL;
+	}
+
+	(void)ib_unregister_event_handler(&device->event_handler);
+	(void)ib_dereg_mr(device->mr);
+	(void)ib_dealloc_pd(device->pd);
+
+	kfree(device->comps);
+	device->comps = NULL;
+
+	device->mr = NULL;
+	device->pd = NULL;
+}
+
+/**
+ * iser_create_fmr_pool - Creates FMR pool and page_vector
+ *
+ * returns 0 on success, or errno code on failure
+ */
+int iser_create_fmr_pool(struct ib_conn *ib_conn, unsigned cmds_max)
+{
+	struct iser_device *device = ib_conn->device;
+	struct ib_fmr_pool_param params;
+	int ret = -ENOMEM;
+
+	ib_conn->fmr.page_vec = kmalloc(sizeof(*ib_conn->fmr.page_vec) +
+					(sizeof(u64)*(ISCSI_ISER_SG_TABLESIZE + 1)),
+					GFP_KERNEL);
+	if (!ib_conn->fmr.page_vec)
+		return ret;
+
+	ib_conn->fmr.page_vec->pages = (u64 *)(ib_conn->fmr.page_vec + 1);
+
+	params.page_shift        = SHIFT_4K;
+	/* when the first/last SG element are not start/end *
+	 * page aligned, the map whould be of N+1 pages     */
+	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
+	/* make the pool size twice the max number of SCSI commands *
+	 * the ML is expected to queue, watermark for unmap at 50%  */
+	params.pool_size	 = cmds_max * 2;
+	params.dirty_watermark	 = cmds_max;
+	params.cache		 = 0;
+	params.flush_function	 = NULL;
+	params.access		 = (IB_ACCESS_LOCAL_WRITE  |
+				    IB_ACCESS_REMOTE_WRITE |
+				    IB_ACCESS_REMOTE_READ);
+
+	ib_conn->fmr.pool = ib_create_fmr_pool(device->pd, &params);
+	if (!IS_ERR(ib_conn->fmr.pool))
+		return 0;
+
+	/* no FMR => no need for page_vec */
+	kfree(ib_conn->fmr.page_vec);
+	ib_conn->fmr.page_vec = NULL;
+
+	ret = PTR_ERR(ib_conn->fmr.pool);
+	ib_conn->fmr.pool = NULL;
+	if (ret != -ENOSYS) {
+		iser_err("FMR allocation failed, err %d\n", ret);
+		return ret;
+	} else {
+		iser_warn("FMRs are not supported, using unaligned mode\n");
+		return 0;
+	}
+}
+
+/**
+ * iser_free_fmr_pool - releases the FMR pool and page vec
+ */
+void iser_free_fmr_pool(struct ib_conn *ib_conn)
+{
+	iser_info("freeing conn %p fmr pool %p\n",
+		  ib_conn, ib_conn->fmr.pool);
+
+	if (ib_conn->fmr.pool != NULL)
+		ib_destroy_fmr_pool(ib_conn->fmr.pool);
+
+	ib_conn->fmr.pool = NULL;
+
+	kfree(ib_conn->fmr.page_vec);
+	ib_conn->fmr.page_vec = NULL;
+}
+
+static int
+iser_alloc_pi_ctx(struct ib_device *ib_device, struct ib_pd *pd,
+		  struct fast_reg_descriptor *desc)
+{
+	struct iser_pi_context *pi_ctx = NULL;
+	struct ib_mr_init_attr mr_init_attr = {.max_reg_descriptors = 2,
+					       .flags = IB_MR_SIGNATURE_EN};
+	int ret = 0;
+
+	desc->pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
+	if (!desc->pi_ctx)
+		return -ENOMEM;
+
+	pi_ctx = desc->pi_ctx;
+
+	pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(ib_device,
+					    ISCSI_ISER_SG_TABLESIZE);
+	if (IS_ERR(pi_ctx->prot_frpl)) {
+		ret = PTR_ERR(pi_ctx->prot_frpl);
+		goto prot_frpl_failure;
+	}
+
+	pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd,
+					ISCSI_ISER_SG_TABLESIZE + 1);
+	if (IS_ERR(pi_ctx->prot_mr)) {
+		ret = PTR_ERR(pi_ctx->prot_mr);
+		goto prot_mr_failure;
+	}
+	desc->reg_indicators |= ISER_PROT_KEY_VALID;
+
+	pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
+	if (IS_ERR(pi_ctx->sig_mr)) {
+		ret = PTR_ERR(pi_ctx->sig_mr);
+		goto sig_mr_failure;
+	}
+	desc->reg_indicators |= ISER_SIG_KEY_VALID;
+	desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
+
+	return 0;
+
+sig_mr_failure:
+	ib_dereg_mr(desc->pi_ctx->prot_mr);
+prot_mr_failure:
+	ib_free_fast_reg_page_list(desc->pi_ctx->prot_frpl);
+prot_frpl_failure:
+	kfree(desc->pi_ctx);
+
+	return ret;
+}
+
+static void
+iser_free_pi_ctx(struct iser_pi_context *pi_ctx)
+{
+	ib_free_fast_reg_page_list(pi_ctx->prot_frpl);
+	ib_dereg_mr(pi_ctx->prot_mr);
+	ib_destroy_mr(pi_ctx->sig_mr);
+	kfree(pi_ctx);
+}
+
+static int
+iser_create_fastreg_desc(struct ib_device *ib_device, struct ib_pd *pd,
+			 bool pi_enable, struct fast_reg_descriptor *desc)
+{
+	int ret;
+
+	desc->data_frpl = ib_alloc_fast_reg_page_list(ib_device,
+						      ISCSI_ISER_SG_TABLESIZE + 1);
+	if (IS_ERR(desc->data_frpl)) {
+		ret = PTR_ERR(desc->data_frpl);
+		iser_err("Failed to allocate ib_fast_reg_page_list err=%d\n",
+			 ret);
+		return PTR_ERR(desc->data_frpl);
+	}
+
+	desc->data_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE + 1);
+	if (IS_ERR(desc->data_mr)) {
+		ret = PTR_ERR(desc->data_mr);
+		iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
+		goto fast_reg_mr_failure;
+	}
+	desc->reg_indicators |= ISER_DATA_KEY_VALID;
+
+	if (pi_enable) {
+		ret = iser_alloc_pi_ctx(ib_device, pd, desc);
+		if (ret)
+			goto pi_ctx_alloc_failure;
+	}
+
+	return 0;
+pi_ctx_alloc_failure:
+	ib_dereg_mr(desc->data_mr);
+fast_reg_mr_failure:
+	ib_free_fast_reg_page_list(desc->data_frpl);
+
+	return ret;
+}
+
+/**
+ * iser_create_fastreg_pool - Creates pool of fast_reg descriptors
+ * for fast registration work requests.
+ * returns 0 on success, or errno code on failure
+ */
+int iser_create_fastreg_pool(struct ib_conn *ib_conn, unsigned cmds_max)
+{
+	struct iser_device *device = ib_conn->device;
+	struct fast_reg_descriptor *desc;
+	int i, ret;
+
+	INIT_LIST_HEAD(&ib_conn->fastreg.pool);
+	ib_conn->fastreg.pool_size = 0;
+	for (i = 0; i < cmds_max; i++) {
+		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+		if (!desc) {
+			iser_err("Failed to allocate a new fast_reg descriptor\n");
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		ret = iser_create_fastreg_desc(device->ib_device, device->pd,
+					       ib_conn->pi_support, desc);
+		if (ret) {
+			iser_err("Failed to create fastreg descriptor err=%d\n",
+				 ret);
+			kfree(desc);
+			goto err;
+		}
+
+		list_add_tail(&desc->list, &ib_conn->fastreg.pool);
+		ib_conn->fastreg.pool_size++;
+	}
+
+	return 0;
+
+err:
+	iser_free_fastreg_pool(ib_conn);
+	return ret;
+}
+
+/**
+ * iser_free_fastreg_pool - releases the pool of fast_reg descriptors
+ */
+void iser_free_fastreg_pool(struct ib_conn *ib_conn)
+{
+	struct fast_reg_descriptor *desc, *tmp;
+	int i = 0;
+
+	if (list_empty(&ib_conn->fastreg.pool))
+		return;
+
+	iser_info("freeing conn %p fr pool\n", ib_conn);
+
+	list_for_each_entry_safe(desc, tmp, &ib_conn->fastreg.pool, list) {
+		list_del(&desc->list);
+		ib_free_fast_reg_page_list(desc->data_frpl);
+		ib_dereg_mr(desc->data_mr);
+		if (desc->pi_ctx)
+			iser_free_pi_ctx(desc->pi_ctx);
+		kfree(desc);
+		++i;
+	}
+
+	if (i < ib_conn->fastreg.pool_size)
+		iser_warn("pool still has %d regions registered\n",
+			  ib_conn->fastreg.pool_size - i);
+}
+
+/**
+ * iser_create_ib_conn_res - Queue-Pair (QP)
+ *
+ * returns 0 on success, -1 on failure
+ */
+static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
+{
+	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
+						   ib_conn);
+	struct iser_device	*device;
+	struct ib_device_attr *dev_attr;
+	struct ib_qp_init_attr	init_attr;
+	int			ret = -ENOMEM;
+	int index, min_index = 0;
+
+	BUG_ON(ib_conn->device == NULL);
+
+	device = ib_conn->device;
+	dev_attr = &device->dev_attr;
+
+	memset(&init_attr, 0, sizeof init_attr);
+
+	mutex_lock(&ig.connlist_mutex);
+	/* select the CQ with the minimal number of usages */
+	for (index = 0; index < device->comps_used; index++) {
+		if (device->comps[index].active_qps <
+		    device->comps[min_index].active_qps)
+			min_index = index;
+	}
+	ib_conn->comp = &device->comps[min_index];
+	ib_conn->comp->active_qps++;
+	mutex_unlock(&ig.connlist_mutex);
+	iser_info("cq index %d used for ib_conn %p\n", min_index, ib_conn);
+
+	init_attr.event_handler = iser_qp_event_callback;
+	init_attr.qp_context	= (void *)ib_conn;
+	init_attr.send_cq	= ib_conn->comp->cq;
+	init_attr.recv_cq	= ib_conn->comp->cq;
+	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
+	init_attr.cap.max_send_sge = 2;
+	init_attr.cap.max_recv_sge = 1;
+	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;
+	init_attr.qp_type	= IB_QPT_RC;
+	if (ib_conn->pi_support) {
+		init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
+		init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
+		iser_conn->max_cmds =
+			ISER_GET_MAX_XMIT_CMDS(ISER_QP_SIG_MAX_REQ_DTOS);
+	} else {
+		if (dev_attr->max_qp_wr > ISER_QP_MAX_REQ_DTOS) {
+			init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS + 1;
+			iser_conn->max_cmds =
+				ISER_GET_MAX_XMIT_CMDS(ISER_QP_MAX_REQ_DTOS);
+		} else {
+			init_attr.cap.max_send_wr = dev_attr->max_qp_wr;
+			iser_conn->max_cmds =
+				ISER_GET_MAX_XMIT_CMDS(dev_attr->max_qp_wr);
+			iser_dbg("device %s supports max_send_wr %d\n",
+				 device->ib_device->name, dev_attr->max_qp_wr);
+		}
+	}
+
+	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
+	if (ret)
+		goto out_err;
+
+	ib_conn->qp = ib_conn->cma_id->qp;
+	iser_info("setting conn %p cma_id %p qp %p\n",
+		  ib_conn, ib_conn->cma_id,
+		  ib_conn->cma_id->qp);
+	return ret;
+
+out_err:
+	mutex_lock(&ig.connlist_mutex);
+	ib_conn->comp->active_qps--;
+	mutex_unlock(&ig.connlist_mutex);
+	iser_err("unable to alloc mem or create resource, err %d\n", ret);
+
+	return ret;
+}
+
+/**
+ * based on the resolved device node GUID see if there already allocated
+ * device for this device. If there's no such, create one.
+ */
+static
+struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
+{
+	struct iser_device *device;
+
+	mutex_lock(&ig.device_list_mutex);
+
+	list_for_each_entry(device, &ig.device_list, ig_list)
+		/* find if there's a match using the node GUID */
+		if (device->ib_device->node_guid == cma_id->device->node_guid)
+			goto inc_refcnt;
+
+	device = kzalloc(sizeof *device, GFP_KERNEL);
+	if (device == NULL)
+		goto out;
+
+	/* assign this device to the device */
+	device->ib_device = cma_id->device;
+	/* init the device and link it into ig device list */
+	if (iser_create_device_ib_res(device)) {
+		kfree(device);
+		device = NULL;
+		goto out;
+	}
+	list_add(&device->ig_list, &ig.device_list);
+
+inc_refcnt:
+	device->refcount++;
+out:
+	mutex_unlock(&ig.device_list_mutex);
+	return device;
+}
+
+/* if there's no demand for this device, release it */
+static void iser_device_try_release(struct iser_device *device)
+{
+	mutex_lock(&ig.device_list_mutex);
+	device->refcount--;
+	iser_info("device %p refcount %d\n", device, device->refcount);
+	if (!device->refcount) {
+		iser_free_device_ib_res(device);
+		list_del(&device->ig_list);
+		kfree(device);
+	}
+	mutex_unlock(&ig.device_list_mutex);
+}
+
+/**
+ * Called with state mutex held
+ **/
+static int iser_conn_state_comp_exch(struct iser_conn *iser_conn,
+				     enum iser_conn_state comp,
+				     enum iser_conn_state exch)
+{
+	int ret;
+
+	ret = (iser_conn->state == comp);
+	if (ret)
+		iser_conn->state = exch;
+
+	return ret;
+}
+
+void iser_release_work(struct work_struct *work)
+{
+	struct iser_conn *iser_conn;
+
+	iser_conn = container_of(work, struct iser_conn, release_work);
+
+	/* Wait for conn_stop to complete */
+	wait_for_completion(&iser_conn->stop_completion);
+	/* Wait for IB resouces cleanup to complete */
+	wait_for_completion(&iser_conn->ib_completion);
+
+	mutex_lock(&iser_conn->state_mutex);
+	iser_conn->state = ISER_CONN_DOWN;
+	mutex_unlock(&iser_conn->state_mutex);
+
+	iser_conn_release(iser_conn);
+}
+
+/**
+ * iser_free_ib_conn_res - release IB related resources
+ * @iser_conn: iser connection struct
+ * @destroy: indicator if we need to try to release the
+ *     iser device and memory regoins pool (only iscsi
+ *     shutdown and DEVICE_REMOVAL will use this).
+ *
+ * This routine is called with the iser state mutex held
+ * so the cm_id removal is out of here. It is Safe to
+ * be invoked multiple times.
+ */
+static void iser_free_ib_conn_res(struct iser_conn *iser_conn,
+				  bool destroy)
+{
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	struct iser_device *device = ib_conn->device;
+
+	iser_info("freeing conn %p cma_id %p qp %p\n",
+		  iser_conn, ib_conn->cma_id, ib_conn->qp);
+
+	if (ib_conn->qp != NULL) {
+		ib_conn->comp->active_qps--;
+		rdma_destroy_qp(ib_conn->cma_id);
+		ib_conn->qp = NULL;
+	}
+
+	if (destroy) {
+		if (iser_conn->rx_descs)
+			iser_free_rx_descriptors(iser_conn);
+
+		if (device != NULL) {
+			iser_device_try_release(device);
+			ib_conn->device = NULL;
+		}
+	}
+}
+
+/**
+ * Frees all conn objects and deallocs conn descriptor
+ */
+void iser_conn_release(struct iser_conn *iser_conn)
+{
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+
+	mutex_lock(&ig.connlist_mutex);
+	list_del(&iser_conn->conn_list);
+	mutex_unlock(&ig.connlist_mutex);
+
+	mutex_lock(&iser_conn->state_mutex);
+	/* In case we endup here without ep_disconnect being invoked. */
+	if (iser_conn->state != ISER_CONN_DOWN) {
+		iser_warn("iser conn %p state %d, expected state down.\n",
+			  iser_conn, iser_conn->state);
+		iscsi_destroy_endpoint(iser_conn->ep);
+		iser_conn->state = ISER_CONN_DOWN;
+	}
+	/*
+	 * In case we never got to bind stage, we still need to
+	 * release IB resources (which is safe to call more than once).
+	 */
+	iser_free_ib_conn_res(iser_conn, true);
+	mutex_unlock(&iser_conn->state_mutex);
+
+	if (ib_conn->cma_id != NULL) {
+		rdma_destroy_id(ib_conn->cma_id);
+		ib_conn->cma_id = NULL;
+	}
+
+	kfree(iser_conn);
+}
+
+/**
+ * triggers start of the disconnect procedures and wait for them to be done
+ * Called with state mutex held
+ */
+int iser_conn_terminate(struct iser_conn *iser_conn)
+{
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	struct ib_send_wr *bad_wr;
+	int err = 0;
+
+	/* terminate the iser conn only if the conn state is UP */
+	if (!iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
+				       ISER_CONN_TERMINATING))
+		return 0;
+
+	iser_info("iser_conn %p state %d\n", iser_conn, iser_conn->state);
+
+	/* suspend queuing of new iscsi commands */
+	if (iser_conn->iscsi_conn)
+		iscsi_suspend_queue(iser_conn->iscsi_conn);
+
+	/*
+	 * In case we didn't already clean up the cma_id (peer initiated
+	 * a disconnection), we need to Cause the CMA to change the QP
+	 * state to ERROR.
+	 */
+	if (ib_conn->cma_id) {
+		err = rdma_disconnect(ib_conn->cma_id);
+		if (err)
+			iser_err("Failed to disconnect, conn: 0x%p err %d\n",
+				 iser_conn, err);
+
+		/* post an indication that all flush errors were consumed */
+		err = ib_post_send(ib_conn->qp, &ib_conn->beacon, &bad_wr);
+		if (err) {
+			iser_err("conn %p failed to post beacon", ib_conn);
+			return 1;
+		}
+
+		wait_for_completion(&ib_conn->flush_comp);
+	}
+
+	return 1;
+}
+
+/**
+ * Called with state mutex held
+ **/
+static void iser_connect_error(struct rdma_cm_id *cma_id)
+{
+	struct iser_conn *iser_conn;
+
+	iser_conn = (struct iser_conn *)cma_id->context;
+	iser_conn->state = ISER_CONN_TERMINATING;
+}
+
+/**
+ * Called with state mutex held
+ **/
+static void iser_addr_handler(struct rdma_cm_id *cma_id)
+{
+	struct iser_device *device;
+	struct iser_conn   *iser_conn;
+	struct ib_conn   *ib_conn;
+	int    ret;
+
+	iser_conn = (struct iser_conn *)cma_id->context;
+	if (iser_conn->state != ISER_CONN_PENDING)
+		/* bailout */
+		return;
+
+	ib_conn = &iser_conn->ib_conn;
+	device = iser_device_find_by_ib_device(cma_id);
+	if (!device) {
+		iser_err("device lookup/creation failed\n");
+		iser_connect_error(cma_id);
+		return;
+	}
+
+	ib_conn->device = device;
+
+	/* connection T10-PI support */
+	if (iser_pi_enable) {
+		if (!(device->dev_attr.device_cap_flags &
+		      IB_DEVICE_SIGNATURE_HANDOVER)) {
+			iser_warn("T10-PI requested but not supported on %s, "
+				  "continue without T10-PI\n",
+				  ib_conn->device->ib_device->name);
+			ib_conn->pi_support = false;
+		} else {
+			ib_conn->pi_support = true;
+		}
+	}
+
+	ret = rdma_resolve_route(cma_id, 1000);
+	if (ret) {
+		iser_err("resolve route failed: %d\n", ret);
+		iser_connect_error(cma_id);
+		return;
+	}
+}
+
+/**
+ * Called with state mutex held
+ **/
+static void iser_route_handler(struct rdma_cm_id *cma_id)
+{
+	struct rdma_conn_param conn_param;
+	int    ret;
+	struct iser_cm_hdr req_hdr;
+	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	struct iser_device *device = ib_conn->device;
+
+	if (iser_conn->state != ISER_CONN_PENDING)
+		/* bailout */
+		return;
+
+	ret = iser_create_ib_conn_res(ib_conn);
+	if (ret)
+		goto failure;
+
+	memset(&conn_param, 0, sizeof conn_param);
+	conn_param.responder_resources = device->dev_attr.max_qp_rd_atom;
+	conn_param.initiator_depth     = 1;
+	conn_param.retry_count	       = 7;
+	conn_param.rnr_retry_count     = 6;
+
+	memset(&req_hdr, 0, sizeof(req_hdr));
+	req_hdr.flags = (ISER_ZBVA_NOT_SUPPORTED |
+			ISER_SEND_W_INV_NOT_SUPPORTED);
+	conn_param.private_data		= (void *)&req_hdr;
+	conn_param.private_data_len	= sizeof(struct iser_cm_hdr);
+
+	ret = rdma_connect(cma_id, &conn_param);
+	if (ret) {
+		iser_err("failure connecting: %d\n", ret);
+		goto failure;
+	}
+
+	return;
+failure:
+	iser_connect_error(cma_id);
+}
+
+static void iser_connected_handler(struct rdma_cm_id *cma_id)
+{
+	struct iser_conn *iser_conn;
+	struct ib_qp_attr attr;
+	struct ib_qp_init_attr init_attr;
+
+	iser_conn = (struct iser_conn *)cma_id->context;
+	if (iser_conn->state != ISER_CONN_PENDING)
+		/* bailout */
+		return;
+
+	(void)ib_query_qp(cma_id->qp, &attr, ~0, &init_attr);
+	iser_info("remote qpn:%x my qpn:%x\n", attr.dest_qp_num, cma_id->qp->qp_num);
+
+	iser_conn->state = ISER_CONN_UP;
+	complete(&iser_conn->up_completion);
+}
+
+static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
+{
+	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
+
+	if (iser_conn_terminate(iser_conn)) {
+		if (iser_conn->iscsi_conn)
+			iscsi_conn_failure(iser_conn->iscsi_conn,
+					   ISCSI_ERR_CONN_FAILED);
+		else
+			iser_err("iscsi_iser connection isn't bound\n");
+	}
+}
+
+static void iser_cleanup_handler(struct rdma_cm_id *cma_id,
+				 bool destroy)
+{
+	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
+
+	/*
+	 * We are not guaranteed that we visited disconnected_handler
+	 * by now, call it here to be safe that we handle CM drep
+	 * and flush errors.
+	 */
+	iser_disconnected_handler(cma_id);
+	iser_free_ib_conn_res(iser_conn, destroy);
+	complete(&iser_conn->ib_completion);
+};
+
+static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
+{
+	struct iser_conn *iser_conn;
+	int ret = 0;
+
+	iser_conn = (struct iser_conn *)cma_id->context;
+	iser_info("event %d status %d conn %p id %p\n",
+		  event->event, event->status, cma_id->context, cma_id);
+
+	mutex_lock(&iser_conn->state_mutex);
+	switch (event->event) {
+	case RDMA_CM_EVENT_ADDR_RESOLVED:
+		iser_addr_handler(cma_id);
+		break;
+	case RDMA_CM_EVENT_ROUTE_RESOLVED:
+		iser_route_handler(cma_id);
+		break;
+	case RDMA_CM_EVENT_ESTABLISHED:
+		iser_connected_handler(cma_id);
+		break;
+	case RDMA_CM_EVENT_ADDR_ERROR:
+	case RDMA_CM_EVENT_ROUTE_ERROR:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	case RDMA_CM_EVENT_UNREACHABLE:
+	case RDMA_CM_EVENT_REJECTED:
+		iser_connect_error(cma_id);
+		break;
+	case RDMA_CM_EVENT_DISCONNECTED:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+		iser_cleanup_handler(cma_id, false);
+		break;
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+		/*
+		 * we *must* destroy the device as we cannot rely
+		 * on iscsid to be around to initiate error handling.
+		 * also if we are not in state DOWN implicitly destroy
+		 * the cma_id.
+		 */
+		iser_cleanup_handler(cma_id, true);
+		if (iser_conn->state != ISER_CONN_DOWN) {
+			iser_conn->ib_conn.cma_id = NULL;
+			ret = 1;
+		}
+		break;
+	default:
+		iser_err("Unexpected RDMA CM event (%d)\n", event->event);
+		break;
+	}
+	mutex_unlock(&iser_conn->state_mutex);
+
+	return ret;
+}
+
+void iser_conn_init(struct iser_conn *iser_conn)
+{
+	iser_conn->state = ISER_CONN_INIT;
+	iser_conn->ib_conn.post_recv_buf_count = 0;
+	init_completion(&iser_conn->ib_conn.flush_comp);
+	init_completion(&iser_conn->stop_completion);
+	init_completion(&iser_conn->ib_completion);
+	init_completion(&iser_conn->up_completion);
+	INIT_LIST_HEAD(&iser_conn->conn_list);
+	spin_lock_init(&iser_conn->ib_conn.lock);
+	mutex_init(&iser_conn->state_mutex);
+}
+
+ /**
+ * starts the process of connecting to the target
+ * sleeps until the connection is established or rejected
+ */
+int iser_connect(struct iser_conn   *iser_conn,
+		 struct sockaddr    *src_addr,
+		 struct sockaddr    *dst_addr,
+		 int                 non_blocking)
+{
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	int err = 0;
+
+	mutex_lock(&iser_conn->state_mutex);
+
+	sprintf(iser_conn->name, "%pISp", dst_addr);
+
+	iser_info("connecting to: %s\n", iser_conn->name);
+
+	/* the device is known only --after-- address resolution */
+	ib_conn->device = NULL;
+
+	iser_conn->state = ISER_CONN_PENDING;
+
+	ib_conn->beacon.wr_id = ISER_BEACON_WRID;
+	ib_conn->beacon.opcode = IB_WR_SEND;
+
+	ib_conn->cma_id = rdma_create_id(iser_cma_handler,
+					 (void *)iser_conn,
+					 RDMA_PS_TCP, IB_QPT_RC);
+	if (IS_ERR(ib_conn->cma_id)) {
+		err = PTR_ERR(ib_conn->cma_id);
+		iser_err("rdma_create_id failed: %d\n", err);
+		goto id_failure;
+	}
+
+	err = rdma_resolve_addr(ib_conn->cma_id, src_addr, dst_addr, 1000);
+	if (err) {
+		iser_err("rdma_resolve_addr failed: %d\n", err);
+		goto addr_failure;
+	}
+
+	if (!non_blocking) {
+		wait_for_completion_interruptible(&iser_conn->up_completion);
+
+		if (iser_conn->state != ISER_CONN_UP) {
+			err =  -EIO;
+			goto connect_failure;
+		}
+	}
+	mutex_unlock(&iser_conn->state_mutex);
+
+	mutex_lock(&ig.connlist_mutex);
+	list_add(&iser_conn->conn_list, &ig.connlist);
+	mutex_unlock(&ig.connlist_mutex);
+	return 0;
+
+id_failure:
+	ib_conn->cma_id = NULL;
+addr_failure:
+	iser_conn->state = ISER_CONN_DOWN;
+connect_failure:
+	mutex_unlock(&iser_conn->state_mutex);
+	iser_conn_release(iser_conn);
+	return err;
+}
+
+int iser_post_recvl(struct iser_conn *iser_conn)
+{
+	struct ib_recv_wr rx_wr, *rx_wr_failed;
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	struct ib_sge	  sge;
+	int ib_ret;
+
+	sge.addr   = iser_conn->login_resp_dma;
+	sge.length = ISER_RX_LOGIN_SIZE;
+	sge.lkey   = ib_conn->device->mr->lkey;
+
+	rx_wr.wr_id   = (uintptr_t)iser_conn->login_resp_buf;
+	rx_wr.sg_list = &sge;
+	rx_wr.num_sge = 1;
+	rx_wr.next    = NULL;
+
+	ib_conn->post_recv_buf_count++;
+	ib_ret	= ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
+	if (ib_ret) {
+		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
+		ib_conn->post_recv_buf_count--;
+	}
+	return ib_ret;
+}
+
+int iser_post_recvm(struct iser_conn *iser_conn, int count)
+{
+	struct ib_recv_wr *rx_wr, *rx_wr_failed;
+	int i, ib_ret;
+	struct ib_conn *ib_conn = &iser_conn->ib_conn;
+	unsigned int my_rx_head = iser_conn->rx_desc_head;
+	struct iser_rx_desc *rx_desc;
+
+	for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
+		rx_desc		= &iser_conn->rx_descs[my_rx_head];
+		rx_wr->wr_id	= (uintptr_t)rx_desc;
+		rx_wr->sg_list	= &rx_desc->rx_sg;
+		rx_wr->num_sge	= 1;
+		rx_wr->next	= rx_wr + 1;
+		my_rx_head = (my_rx_head + 1) & iser_conn->qp_max_recv_dtos_mask;
+	}
+
+	rx_wr--;
+	rx_wr->next = NULL; /* mark end of work requests list */
+
+	ib_conn->post_recv_buf_count += count;
+	ib_ret	= ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
+	if (ib_ret) {
+		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
+		ib_conn->post_recv_buf_count -= count;
+	} else
+		iser_conn->rx_desc_head = my_rx_head;
+	return ib_ret;
+}
+
+
+/**
+ * iser_start_send - Initiate a Send DTO operation
+ *
+ * returns 0 on success, -1 on failure
+ */
+int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc,
+		   bool signal)
+{
+	int		  ib_ret;
+	struct ib_send_wr send_wr, *send_wr_failed;
+
+	ib_dma_sync_single_for_device(ib_conn->device->ib_device,
+				      tx_desc->dma_addr, ISER_HEADERS_LEN,
+				      DMA_TO_DEVICE);
+
+	send_wr.next	   = NULL;
+	send_wr.wr_id	   = (uintptr_t)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 = signal ? IB_SEND_SIGNALED : 0;
+
+	ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
+	if (ib_ret)
+		iser_err("ib_post_send failed, ret:%d\n", ib_ret);
+
+	return ib_ret;
+}
+
+/**
+ * is_iser_tx_desc - Indicate if the completion wr_id
+ *     is a TX descriptor or not.
+ * @iser_conn: iser connection
+ * @wr_id: completion WR identifier
+ *
+ * Since we cannot rely on wc opcode in FLUSH errors
+ * we must work around it by checking if the wr_id address
+ * falls in the iser connection rx_descs buffer. If so
+ * it is an RX descriptor, otherwize it is a TX.
+ */
+static inline bool
+is_iser_tx_desc(struct iser_conn *iser_conn, void *wr_id)
+{
+	void *start = iser_conn->rx_descs;
+	int len = iser_conn->num_rx_descs * sizeof(*iser_conn->rx_descs);
+
+	if (wr_id >= start && wr_id < start + len)
+		return false;
+
+	return true;
+}
+
+/**
+ * iser_handle_comp_error() - Handle error completion
+ * @ib_conn:   connection RDMA resources
+ * @wc:        work completion
+ *
+ * Notes: We may handle a FLUSH error completion and in this case
+ *        we only cleanup in case TX type was DATAOUT. For non-FLUSH
+ *        error completion we should also notify iscsi layer that
+ *        connection is failed (in case we passed bind stage).
+ */
+static void
+iser_handle_comp_error(struct ib_conn *ib_conn,
+		       struct ib_wc *wc)
+{
+	void *wr_id = (void *)(uintptr_t)wc->wr_id;
+	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
+						   ib_conn);
+
+	if (wc->status != IB_WC_WR_FLUSH_ERR)
+		if (iser_conn->iscsi_conn)
+			iscsi_conn_failure(iser_conn->iscsi_conn,
+					   ISCSI_ERR_CONN_FAILED);
+
+	if (wc->wr_id == ISER_FASTREG_LI_WRID)
+		return;
+
+	if (is_iser_tx_desc(iser_conn, wr_id)) {
+		struct iser_tx_desc *desc = wr_id;
+
+		if (desc->type == ISCSI_TX_DATAOUT)
+			kmem_cache_free(ig.desc_cache, desc);
+	} else {
+		ib_conn->post_recv_buf_count--;
+	}
+}
+
+/**
+ * iser_handle_wc - handle a single work completion
+ * @wc: work completion
+ *
+ * Soft-IRQ context, work completion can be either
+ * SEND or RECV, and can turn out successful or
+ * with error (or flush error).
+ */
+static void iser_handle_wc(struct ib_wc *wc)
+{
+	struct ib_conn *ib_conn;
+	struct iser_tx_desc *tx_desc;
+	struct iser_rx_desc *rx_desc;
+
+	ib_conn = wc->qp->qp_context;
+	if (likely(wc->status == IB_WC_SUCCESS)) {
+		if (wc->opcode == IB_WC_RECV) {
+			rx_desc = (struct iser_rx_desc *)(uintptr_t)wc->wr_id;
+			iser_rcv_completion(rx_desc, wc->byte_len,
+					    ib_conn);
+		} else
+		if (wc->opcode == IB_WC_SEND) {
+			tx_desc = (struct iser_tx_desc *)(uintptr_t)wc->wr_id;
+			iser_snd_completion(tx_desc, ib_conn);
+		} else {
+			iser_err("Unknown wc opcode %d\n", wc->opcode);
+		}
+	} else {
+		if (wc->status != IB_WC_WR_FLUSH_ERR)
+			iser_err("wr id %llx status %d vend_err %x\n",
+				 wc->wr_id, wc->status, wc->vendor_err);
+		else
+			iser_dbg("flush error: wr id %llx\n", wc->wr_id);
+
+		if (wc->wr_id == ISER_BEACON_WRID)
+			/* all flush errors were consumed */
+			complete(&ib_conn->flush_comp);
+		else
+			iser_handle_comp_error(ib_conn, wc);
+	}
+}
+
+/**
+ * iser_cq_tasklet_fn - iSER completion polling loop
+ * @data: iSER completion context
+ *
+ * Soft-IRQ context, polling connection CQ until
+ * either CQ was empty or we exausted polling budget
+ */
+static void iser_cq_tasklet_fn(unsigned long data)
+{
+	struct iser_comp *comp = (struct iser_comp *)data;
+	struct ib_cq *cq = comp->cq;
+	struct ib_wc *const wcs = comp->wcs;
+	int i, n, completed = 0;
+
+	while ((n = ib_poll_cq(cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
+		for (i = 0; i < n; i++)
+			iser_handle_wc(&wcs[i]);
+
+		completed += n;
+		if (completed >= iser_cq_poll_limit)
+			break;
+	}
+
+	/*
+	 * It is assumed here that arming CQ only once its empty
+	 * would not cause interrupts to be missed.
+	 */
+	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
+
+	iser_dbg("got %d completions\n", completed);
+}
+
+static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
+{
+	struct iser_comp *comp = cq_context;
+
+	tasklet_schedule(&comp->tasklet);
+}
+
+u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
+			     enum iser_data_dir cmd_dir, sector_t *sector)
+{
+	struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
+	struct fast_reg_descriptor *desc = reg->mem_h;
+	unsigned long sector_size = iser_task->sc->device->sector_size;
+	struct ib_mr_status mr_status;
+	int ret;
+
+	if (desc && desc->reg_indicators & ISER_FASTREG_PROTECTED) {
+		desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
+		ret = ib_check_mr_status(desc->pi_ctx->sig_mr,
+					 IB_MR_CHECK_SIG_STATUS, &mr_status);
+		if (ret) {
+			pr_err("ib_check_mr_status failed, ret %d\n", ret);
+			goto err;
+		}
+
+		if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
+			sector_t sector_off = mr_status.sig_err.sig_err_offset;
+
+			do_div(sector_off, sector_size + 8);
+			*sector = scsi_get_lba(iser_task->sc) + sector_off;
+
+			pr_err("PI error found type %d at sector %llx "
+			       "expected %x vs actual %x\n",
+			       mr_status.sig_err.err_type,
+			       (unsigned long long)*sector,
+			       mr_status.sig_err.expected,
+			       mr_status.sig_err.actual);
+
+			switch (mr_status.sig_err.err_type) {
+			case IB_SIG_BAD_GUARD:
+				return 0x1;
+			case IB_SIG_BAD_REFTAG:
+				return 0x3;
+			case IB_SIG_BAD_APPTAG:
+				return 0x2;
+			}
+		}
+	}
+
+	return 0;
+err:
+	/* Not alot we can do here, return ambiguous guard error */
+	return 0x1;
+}