drivers/infiniband/ulp/rtrs/rtrs.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * RDMA Transport Layer
  *
  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
  */
 #undef pr_fmt
 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt

 #include <linux/module.h>
 #include <linux/inet.h>

 #include "rtrs-pri.h"
 #include "rtrs-log.h"

 MODULE_DESCRIPTION("RDMA Transport Core");
 MODULE_LICENSE("GPL");

 struct rtrs_iu *rtrs_iu_alloc(u32 iu_num, size_t size, gfp_t gfp_mask,
 			      struct ib_device *dma_dev,
 			      enum dma_data_direction dir,
 			      void (*done)(struct ib_cq *cq, struct ib_wc *wc))
 {
 	struct rtrs_iu *ius, *iu;
 	int i;

 	ius = kcalloc(iu_num, sizeof(*ius), gfp_mask);
 	if (!ius)
 		return NULL;
 	for (i = 0; i < iu_num; i++) {
 		iu = &ius[i];
 		iu->direction = dir;
 		iu->buf = kzalloc(size, gfp_mask);
 		if (!iu->buf)
 			goto err;

 		iu->dma_addr = ib_dma_map_single(dma_dev, iu->buf, size, dir);
 		if (ib_dma_mapping_error(dma_dev, iu->dma_addr))
 			goto err;

 		iu->cqe.done  = done;
 		iu->size      = size;
 	}
 	return ius;
 err:
 	rtrs_iu_free(ius, dma_dev, i);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(rtrs_iu_alloc);

 void rtrs_iu_free(struct rtrs_iu *ius, struct ib_device *ibdev, u32 queue_num)
 {
 	struct rtrs_iu *iu;
 	int i;

 	if (!ius)
 		return;

 	for (i = 0; i < queue_num; i++) {
 		iu = &ius[i];
 		ib_dma_unmap_single(ibdev, iu->dma_addr, iu->size, iu->direction);
 		kfree(iu->buf);
 	}
 	kfree(ius);
 }
 EXPORT_SYMBOL_GPL(rtrs_iu_free);

 int rtrs_iu_post_recv(struct rtrs_con *con, struct rtrs_iu *iu)
 {
 	struct rtrs_sess *sess = con->sess;
 	struct ib_recv_wr wr;
 	struct ib_sge list;

 	list.addr   = iu->dma_addr;
 	list.length = iu->size;
 	list.lkey   = sess->dev->ib_pd->local_dma_lkey;

 	if (list.length == 0) {
 		rtrs_wrn(con->sess,
 			  "Posting receive work request failed, sg list is empty\n");
 		return -EINVAL;
 	}
 	wr = (struct ib_recv_wr) {
 		.wr_cqe  = &iu->cqe,
 		.sg_list = &list,
 		.num_sge = 1,
 	};

 	return ib_post_recv(con->qp, &wr, NULL);
 }
 EXPORT_SYMBOL_GPL(rtrs_iu_post_recv);

 int rtrs_post_recv_empty(struct rtrs_con *con, struct ib_cqe *cqe)
 {
 	struct ib_recv_wr wr;

 	wr = (struct ib_recv_wr) {
 		.wr_cqe  = cqe,
 	};

 	return ib_post_recv(con->qp, &wr, NULL);
 }
 EXPORT_SYMBOL_GPL(rtrs_post_recv_empty);

 static int rtrs_post_send(struct ib_qp *qp, struct ib_send_wr *head,
 			  struct ib_send_wr *wr, struct ib_send_wr *tail)
 {
 	if (head) {
 		struct ib_send_wr *next = head;

 		while (next->next)
 			next = next->next;
 		next->next = wr;
 	} else {
 		head = wr;
 	}

 	if (tail)
 		wr->next = tail;

 	return ib_post_send(qp, head, NULL);
 }

 int rtrs_iu_post_send(struct rtrs_con *con, struct rtrs_iu *iu, size_t size,
 		       struct ib_send_wr *head)
 {
 	struct rtrs_sess *sess = con->sess;
 	struct ib_send_wr wr;
 	struct ib_sge list;

 	if (WARN_ON(size == 0))
 		return -EINVAL;

 	list.addr   = iu->dma_addr;
 	list.length = size;
 	list.lkey   = sess->dev->ib_pd->local_dma_lkey;

 	wr = (struct ib_send_wr) {
 		.wr_cqe     = &iu->cqe,
 		.sg_list    = &list,
 		.num_sge    = 1,
 		.opcode     = IB_WR_SEND,
 		.send_flags = IB_SEND_SIGNALED,
 	};

 	return rtrs_post_send(con->qp, head, &wr, NULL);
 }
 EXPORT_SYMBOL_GPL(rtrs_iu_post_send);

 int rtrs_iu_post_rdma_write_imm(struct rtrs_con *con, struct rtrs_iu *iu,
 				struct ib_sge *sge, unsigned int num_sge,
 				u32 rkey, u64 rdma_addr, u32 imm_data,
 				enum ib_send_flags flags,
 				struct ib_send_wr *head,
 				struct ib_send_wr *tail)
 {
 	struct ib_rdma_wr wr;
 	int i;

 	wr = (struct ib_rdma_wr) {
 		.wr.wr_cqe	  = &iu->cqe,
 		.wr.sg_list	  = sge,
 		.wr.num_sge	  = num_sge,
 		.rkey		  = rkey,
 		.remote_addr	  = rdma_addr,
 		.wr.opcode	  = IB_WR_RDMA_WRITE_WITH_IMM,
 		.wr.ex.imm_data = cpu_to_be32(imm_data),
 		.wr.send_flags  = flags,
 	};

 	/*
 	 * If one of the sges has 0 size, the operation will fail with a
 	 * length error
 	 */
 	for (i = 0; i < num_sge; i++)
 		if (WARN_ON(sge[i].length == 0))
 			return -EINVAL;

 	return rtrs_post_send(con->qp, head, &wr.wr, tail);
 }
 EXPORT_SYMBOL_GPL(rtrs_iu_post_rdma_write_imm);

 static int rtrs_post_rdma_write_imm_empty(struct rtrs_con *con,
 					  struct ib_cqe *cqe,
 					  u32 imm_data,
 					  struct ib_send_wr *head)
 {
 	struct ib_rdma_wr wr;
 	struct rtrs_sess *sess = con->sess;
 	enum ib_send_flags sflags;

 	atomic_dec_if_positive(&con->sq_wr_avail);
 	sflags = (atomic_inc_return(&con->wr_cnt) % sess->signal_interval) ?
 		0 : IB_SEND_SIGNALED;

 	wr = (struct ib_rdma_wr) {
 		.wr.wr_cqe	= cqe,
 		.wr.send_flags	= sflags,
 		.wr.opcode	= IB_WR_RDMA_WRITE_WITH_IMM,
 		.wr.ex.imm_data	= cpu_to_be32(imm_data),
 	};

 	return rtrs_post_send(con->qp, head, &wr.wr, NULL);
 }

 static void qp_event_handler(struct ib_event *ev, void *ctx)
 {
 	struct rtrs_con *con = ctx;

 	switch (ev->event) {
 	case IB_EVENT_COMM_EST:
 		rtrs_info(con->sess, "QP event %s (%d) received\n",
 			   ib_event_msg(ev->event), ev->event);
 		rdma_notify(con->cm_id, IB_EVENT_COMM_EST);
 		break;
 	default:
 		rtrs_info(con->sess, "Unhandled QP event %s (%d) received\n",
 			   ib_event_msg(ev->event), ev->event);
 		break;
 	}
 }

 static int create_cq(struct rtrs_con *con, int cq_vector, int nr_cqe,
 		     enum ib_poll_context poll_ctx)
 {
 	struct rdma_cm_id *cm_id = con->cm_id;
 	struct ib_cq *cq;

 	cq = ib_cq_pool_get(cm_id->device, nr_cqe, cq_vector, poll_ctx);
 	if (IS_ERR(cq)) {
 		rtrs_err(con->sess, "Creating completion queue failed, errno: %ld\n",
 			  PTR_ERR(cq));
 		return PTR_ERR(cq);
 	}
 	con->cq = cq;
 	con->nr_cqe = nr_cqe;

 	return 0;
 }

 static int create_qp(struct rtrs_con *con, struct ib_pd *pd,
 		     u32 max_send_wr, u32 max_recv_wr, u32 max_sge)
 {
 	struct ib_qp_init_attr init_attr = {NULL};
 	struct rdma_cm_id *cm_id = con->cm_id;
 	int ret;

 	init_attr.cap.max_send_wr = max_send_wr;
 	init_attr.cap.max_recv_wr = max_recv_wr;
 	init_attr.cap.max_recv_sge = 1;
 	init_attr.event_handler = qp_event_handler;
 	init_attr.qp_context = con;
 	init_attr.cap.max_send_sge = max_sge;

 	init_attr.qp_type = IB_QPT_RC;
 	init_attr.send_cq = con->cq;
 	init_attr.recv_cq = con->cq;
 	init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;

 	ret = rdma_create_qp(cm_id, pd, &init_attr);
 	if (ret) {
 		rtrs_err(con->sess, "Creating QP failed, err: %d\n", ret);
 		return ret;
 	}
 	con->qp = cm_id->qp;

 	return ret;
 }

 int rtrs_cq_qp_create(struct rtrs_sess *sess, struct rtrs_con *con,
 		       u32 max_send_sge, int cq_vector, int nr_cqe,
 		       u32 max_send_wr, u32 max_recv_wr,
 		       enum ib_poll_context poll_ctx)
 {
 	int err;

 	err = create_cq(con, cq_vector, nr_cqe, poll_ctx);
 	if (err)
 		return err;

 	err = create_qp(con, sess->dev->ib_pd, max_send_wr, max_recv_wr,
 			max_send_sge);
 	if (err) {
 		ib_cq_pool_put(con->cq, con->nr_cqe);
 		con->cq = NULL;
 		return err;
 	}
 	con->sess = sess;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rtrs_cq_qp_create);

 void rtrs_cq_qp_destroy(struct rtrs_con *con)
 {
 	if (con->qp) {
 		rdma_destroy_qp(con->cm_id);
 		con->qp = NULL;
 	}
 	if (con->cq) {
 		ib_cq_pool_put(con->cq, con->nr_cqe);
 		con->cq = NULL;
 	}
 }
 EXPORT_SYMBOL_GPL(rtrs_cq_qp_destroy);

 static void schedule_hb(struct rtrs_sess *sess)
 {
 	queue_delayed_work(sess->hb_wq, &sess->hb_dwork,
 			   msecs_to_jiffies(sess->hb_interval_ms));
 }

 void rtrs_send_hb_ack(struct rtrs_sess *sess)
 {
 	struct rtrs_con *usr_con = sess->con[0];
 	u32 imm;
 	int err;

 	imm = rtrs_to_imm(RTRS_HB_ACK_IMM, 0);
 	err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
 					     NULL);
 	if (err) {
 		rtrs_err(sess, "send HB ACK failed, errno: %d\n", err);
 		sess->hb_err_handler(usr_con);
 		return;
 	}
 }
 EXPORT_SYMBOL_GPL(rtrs_send_hb_ack);

 static void hb_work(struct work_struct *work)
 {
 	struct rtrs_con *usr_con;
 	struct rtrs_sess *sess;
 	u32 imm;
 	int err;

 	sess = container_of(to_delayed_work(work), typeof(*sess), hb_dwork);
 	usr_con = sess->con[0];

 	if (sess->hb_missed_cnt > sess->hb_missed_max) {
 		rtrs_err(sess, "HB missed max reached.\n");
 		sess->hb_err_handler(usr_con);
 		return;
 	}
 	if (sess->hb_missed_cnt++) {
 		/* Reschedule work without sending hb */
 		schedule_hb(sess);
 		return;
 	}

 	sess->hb_last_sent = ktime_get();

 	imm = rtrs_to_imm(RTRS_HB_MSG_IMM, 0);
 	err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
 					     NULL);
 	if (err) {
 		rtrs_err(sess, "HB send failed, errno: %d\n", err);
 		sess->hb_err_handler(usr_con);
 		return;
 	}

 	schedule_hb(sess);
 }

 void rtrs_init_hb(struct rtrs_sess *sess, struct ib_cqe *cqe,
 		  unsigned int interval_ms, unsigned int missed_max,
 		  void (*err_handler)(struct rtrs_con *con),
 		  struct workqueue_struct *wq)
 {
 	sess->hb_cqe = cqe;
 	sess->hb_interval_ms = interval_ms;
 	sess->hb_err_handler = err_handler;
 	sess->hb_wq = wq;
 	sess->hb_missed_max = missed_max;
 	sess->hb_missed_cnt = 0;
 	INIT_DELAYED_WORK(&sess->hb_dwork, hb_work);
 }
 EXPORT_SYMBOL_GPL(rtrs_init_hb);

 void rtrs_start_hb(struct rtrs_sess *sess)
 {
 	schedule_hb(sess);
 }
 EXPORT_SYMBOL_GPL(rtrs_start_hb);

 void rtrs_stop_hb(struct rtrs_sess *sess)
 {
 	cancel_delayed_work_sync(&sess->hb_dwork);
 	sess->hb_missed_cnt = 0;
 }
 EXPORT_SYMBOL_GPL(rtrs_stop_hb);

 static int rtrs_str_gid_to_sockaddr(const char *addr, size_t len,
 				     short port, struct sockaddr_storage *dst)
 {
 	struct sockaddr_ib *dst_ib = (struct sockaddr_ib *)dst;
 	int ret;

 	/*
 	 * We can use some of the IPv6 functions since GID is a valid
 	 * IPv6 address format
 	 */
 	ret = in6_pton(addr, len, dst_ib->sib_addr.sib_raw, '\0', NULL);
 	if (ret == 0)
 		return -EINVAL;

 	dst_ib->sib_family = AF_IB;
 	/*
 	 * Use the same TCP server port number as the IB service ID
 	 * on the IB port space range
 	 */
 	dst_ib->sib_sid = cpu_to_be64(RDMA_IB_IP_PS_IB | port);
 	dst_ib->sib_sid_mask = cpu_to_be64(0xffffffffffffffffULL);
 	dst_ib->sib_pkey = cpu_to_be16(0xffff);

 	return 0;
 }

 /**
  * rtrs_str_to_sockaddr() - Convert rtrs address string to sockaddr
  * @addr:	String representation of an addr (IPv4, IPv6 or IB GID):
  *              - "ip:192.168.1.1"
  *              - "ip:fe80::200:5aee:feaa:20a2"
  *              - "gid:fe80::200:5aee:feaa:20a2"
  * @len:        String address length
  * @port:	Destination port
  * @dst:	Destination sockaddr structure
  *
  * Returns 0 if conversion successful. Non-zero on error.
  */
 static int rtrs_str_to_sockaddr(const char *addr, size_t len,
 				u16 port, struct sockaddr_storage *dst)
 {
 	if (strncmp(addr, "gid:", 4) == 0) {
 		return rtrs_str_gid_to_sockaddr(addr + 4, len - 4, port, dst);
 	} else if (strncmp(addr, "ip:", 3) == 0) {
 		char port_str[8];
 		char *cpy;
 		int err;

 		snprintf(port_str, sizeof(port_str), "%u", port);
 		cpy = kstrndup(addr + 3, len - 3, GFP_KERNEL);
 		err = cpy ? inet_pton_with_scope(&init_net, AF_UNSPEC,
 						 cpy, port_str, dst) : -ENOMEM;
 		kfree(cpy);

 		return err;
 	}
 	return -EPROTONOSUPPORT;
 }

 /**
  * sockaddr_to_str() - convert sockaddr to a string.
  * @addr:	the sockadddr structure to be converted.
  * @buf:	string containing socket addr.
  * @len:	string length.
  *
  * The return value is the number of characters written into buf not
  * including the trailing '\0'. If len is == 0 the function returns 0..
  */
 int sockaddr_to_str(const struct sockaddr *addr, char *buf, size_t len)
 {

 	switch (addr->sa_family) {
 	case AF_IB:
 		return scnprintf(buf, len, "gid:%pI6",
 			&((struct sockaddr_ib *)addr)->sib_addr.sib_raw);
 	case AF_INET:
 		return scnprintf(buf, len, "ip:%pI4",
 			&((struct sockaddr_in *)addr)->sin_addr);
 	case AF_INET6:
 		return scnprintf(buf, len, "ip:%pI6c",
 			  &((struct sockaddr_in6 *)addr)->sin6_addr);
 	}
 	return scnprintf(buf, len, "<invalid address family>");
 }
 EXPORT_SYMBOL(sockaddr_to_str);

 /**
  * rtrs_addr_to_str() - convert rtrs_addr to a string "src@dst"
  * @addr:	the rtrs_addr structure to be converted
  * @buf:	string containing source and destination addr of a path
  *		separated by '@' I.e. "ip:1.1.1.1@ip:1.1.1.2"
  *		"ip:1.1.1.1@ip:1.1.1.2".
  * @len:	string length
  *
  * The return value is the number of characters written into buf not
  * including the trailing '\0'.
  */
 int rtrs_addr_to_str(const struct rtrs_addr *addr, char *buf, size_t len)
 {
 	int cnt;

 	cnt = sockaddr_to_str((struct sockaddr *)addr->src,
 			      buf, len);
 	cnt += scnprintf(buf + cnt, len - cnt, "@");
 	sockaddr_to_str((struct sockaddr *)addr->dst,
 			buf + cnt, len - cnt);
 	return cnt;
 }
 EXPORT_SYMBOL(rtrs_addr_to_str);

 /**
  * rtrs_addr_to_sockaddr() - convert path string "src,dst" or "src@dst"
  * to sockaddreses
  * @str:	string containing source and destination addr of a path
  *		separated by ',' or '@' I.e. "ip:1.1.1.1,ip:1.1.1.2" or
  *		"ip:1.1.1.1@ip:1.1.1.2". If str contains only one address it's
  *		considered to be destination.
  * @len:	string length
  * @port:	Destination port number.
  * @addr:	will be set to the source/destination address or to NULL
  *		if str doesn't contain any source address.
  *
  * Returns zero if conversion successful. Non-zero otherwise.
  */
 int rtrs_addr_to_sockaddr(const char *str, size_t len, u16 port,
 			  struct rtrs_addr *addr)
 {
 	const char *d;

 	d = strchr(str, ',');
 	if (!d)
 		d = strchr(str, '@');
 	if (d) {
 		if (rtrs_str_to_sockaddr(str, d - str, 0, addr->src))
 			return -EINVAL;
 		d += 1;
 		len -= d - str;
 		str  = d;

 	} else {
 		addr->src = NULL;
 	}
 	return rtrs_str_to_sockaddr(str, len, port, addr->dst);
 }
 EXPORT_SYMBOL(rtrs_addr_to_sockaddr);

 void rtrs_rdma_dev_pd_init(enum ib_pd_flags pd_flags,
 			    struct rtrs_rdma_dev_pd *pool)
 {
 	WARN_ON(pool->ops && (!pool->ops->alloc ^ !pool->ops->free));
 	INIT_LIST_HEAD(&pool->list);
 	mutex_init(&pool->mutex);
 	pool->pd_flags = pd_flags;
 }
 EXPORT_SYMBOL(rtrs_rdma_dev_pd_init);

 void rtrs_rdma_dev_pd_deinit(struct rtrs_rdma_dev_pd *pool)
 {
 	mutex_destroy(&pool->mutex);
 	WARN_ON(!list_empty(&pool->list));
 }
 EXPORT_SYMBOL(rtrs_rdma_dev_pd_deinit);

 static void dev_free(struct kref *ref)
 {
 	struct rtrs_rdma_dev_pd *pool;
 	struct rtrs_ib_dev *dev;

 	dev = container_of(ref, typeof(*dev), ref);
 	pool = dev->pool;

 	mutex_lock(&pool->mutex);
 	list_del(&dev->entry);
 	mutex_unlock(&pool->mutex);

 	if (pool->ops && pool->ops->deinit)
 		pool->ops->deinit(dev);

 	ib_dealloc_pd(dev->ib_pd);

 	if (pool->ops && pool->ops->free)
 		pool->ops->free(dev);
 	else
 		kfree(dev);
 }

 int rtrs_ib_dev_put(struct rtrs_ib_dev *dev)
 {
 	return kref_put(&dev->ref, dev_free);
 }
 EXPORT_SYMBOL(rtrs_ib_dev_put);

 static int rtrs_ib_dev_get(struct rtrs_ib_dev *dev)
 {
 	return kref_get_unless_zero(&dev->ref);
 }

 struct rtrs_ib_dev *
 rtrs_ib_dev_find_or_add(struct ib_device *ib_dev,
 			 struct rtrs_rdma_dev_pd *pool)
 {
 	struct rtrs_ib_dev *dev;

 	mutex_lock(&pool->mutex);
 	list_for_each_entry(dev, &pool->list, entry) {
 		if (dev->ib_dev->node_guid == ib_dev->node_guid &&
 		    rtrs_ib_dev_get(dev))
 			goto out_unlock;
 	}
 	mutex_unlock(&pool->mutex);
 	if (pool->ops && pool->ops->alloc)
 		dev = pool->ops->alloc();
 	else
 		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (IS_ERR_OR_NULL(dev))
 		goto out_err;

 	kref_init(&dev->ref);
 	dev->pool = pool;
 	dev->ib_dev = ib_dev;
 	dev->ib_pd = ib_alloc_pd(ib_dev, pool->pd_flags);
 	if (IS_ERR(dev->ib_pd))
 		goto out_free_dev;

 	if (pool->ops && pool->ops->init && pool->ops->init(dev))
 		goto out_free_pd;

 	mutex_lock(&pool->mutex);
 	list_add(&dev->entry, &pool->list);
 out_unlock:
 	mutex_unlock(&pool->mutex);
 	return dev;

 out_free_pd:
 	ib_dealloc_pd(dev->ib_pd);
 out_free_dev:
 	if (pool->ops && pool->ops->free)
 		pool->ops->free(dev);
 	else
 		kfree(dev);
 out_err:
 	return NULL;
 }
 EXPORT_SYMBOL(rtrs_ib_dev_find_or_add);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* RDMA Transport Layer
	*
	* Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
	* Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
	* Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
	*/
	#undef pr_fmt
	#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt

	#include <linux/module.h>
	#include <linux/inet.h>

	#include "rtrs-pri.h"
	#include "rtrs-log.h"

	MODULE_DESCRIPTION("RDMA Transport Core");
	MODULE_LICENSE("GPL");

	struct rtrs_iu *rtrs_iu_alloc(u32 iu_num, size_t size, gfp_t gfp_mask,
	struct ib_device *dma_dev,
	enum dma_data_direction dir,
	void (done)(struct ib_cq cq, struct ib_wc *wc))
	{
	struct rtrs_iu ius, iu;
	int i;

	ius = kcalloc(iu_num, sizeof(*ius), gfp_mask);
	if (!ius)
	return NULL;
	for (i = 0; i < iu_num; i++) {
	iu = &ius[i];
	iu->direction = dir;
	iu->buf = kzalloc(size, gfp_mask);
	if (!iu->buf)
	goto err;

	iu->dma_addr = ib_dma_map_single(dma_dev, iu->buf, size, dir);
	if (ib_dma_mapping_error(dma_dev, iu->dma_addr))
	goto err;

	iu->cqe.done = done;
	iu->size = size;
	}
	return ius;
	err:
	rtrs_iu_free(ius, dma_dev, i);
	return NULL;
	}
	EXPORT_SYMBOL_GPL(rtrs_iu_alloc);

	void rtrs_iu_free(struct rtrs_iu ius, struct ib_device ibdev, u32 queue_num)
	{
	struct rtrs_iu *iu;
	int i;

	if (!ius)
	return;

	for (i = 0; i < queue_num; i++) {
	iu = &ius[i];
	ib_dma_unmap_single(ibdev, iu->dma_addr, iu->size, iu->direction);
	kfree(iu->buf);
	}
	kfree(ius);
	}
	EXPORT_SYMBOL_GPL(rtrs_iu_free);

	int rtrs_iu_post_recv(struct rtrs_con con, struct rtrs_iu iu)
	{
	struct rtrs_sess *sess = con->sess;
	struct ib_recv_wr wr;
	struct ib_sge list;

	list.addr = iu->dma_addr;
	list.length = iu->size;
	list.lkey = sess->dev->ib_pd->local_dma_lkey;

	if (list.length == 0) {
	rtrs_wrn(con->sess,
	"Posting receive work request failed, sg list is empty\n");
	return -EINVAL;
	}
	wr = (struct ib_recv_wr) {
	.wr_cqe = &iu->cqe,
	.sg_list = &list,
	.num_sge = 1,
	};

	return ib_post_recv(con->qp, &wr, NULL);
	}
	EXPORT_SYMBOL_GPL(rtrs_iu_post_recv);

	int rtrs_post_recv_empty(struct rtrs_con con, struct ib_cqe cqe)
	{
	struct ib_recv_wr wr;

	wr = (struct ib_recv_wr) {
	.wr_cqe = cqe,
	};

	return ib_post_recv(con->qp, &wr, NULL);
	}
	EXPORT_SYMBOL_GPL(rtrs_post_recv_empty);

	static int rtrs_post_send(struct ib_qp qp, struct ib_send_wr head,
	struct ib_send_wr wr, struct ib_send_wr tail)
	{
	if (head) {
	struct ib_send_wr *next = head;

	while (next->next)
	next = next->next;
	next->next = wr;
	} else {
	head = wr;
	}

	if (tail)
	wr->next = tail;

	return ib_post_send(qp, head, NULL);
	}

	int rtrs_iu_post_send(struct rtrs_con con, struct rtrs_iu iu, size_t size,
	struct ib_send_wr *head)
	{
	struct rtrs_sess *sess = con->sess;
	struct ib_send_wr wr;
	struct ib_sge list;

	if (WARN_ON(size == 0))
	return -EINVAL;

	list.addr = iu->dma_addr;
	list.length = size;
	list.lkey = sess->dev->ib_pd->local_dma_lkey;

	wr = (struct ib_send_wr) {
	.wr_cqe = &iu->cqe,
	.sg_list = &list,
	.num_sge = 1,
	.opcode = IB_WR_SEND,
	.send_flags = IB_SEND_SIGNALED,
	};

	return rtrs_post_send(con->qp, head, &wr, NULL);
	}
	EXPORT_SYMBOL_GPL(rtrs_iu_post_send);

	int rtrs_iu_post_rdma_write_imm(struct rtrs_con con, struct rtrs_iu iu,
	struct ib_sge *sge, unsigned int num_sge,
	u32 rkey, u64 rdma_addr, u32 imm_data,
	enum ib_send_flags flags,
	struct ib_send_wr *head,
	struct ib_send_wr *tail)
	{
	struct ib_rdma_wr wr;
	int i;

	wr = (struct ib_rdma_wr) {
	.wr.wr_cqe = &iu->cqe,
	.wr.sg_list = sge,
	.wr.num_sge = num_sge,
	.rkey = rkey,
	.remote_addr = rdma_addr,
	.wr.opcode = IB_WR_RDMA_WRITE_WITH_IMM,
	.wr.ex.imm_data = cpu_to_be32(imm_data),
	.wr.send_flags = flags,
	};

	/*
	* If one of the sges has 0 size, the operation will fail with a
	* length error
	*/
	for (i = 0; i < num_sge; i++)
	if (WARN_ON(sge[i].length == 0))
	return -EINVAL;

	return rtrs_post_send(con->qp, head, &wr.wr, tail);
	}
	EXPORT_SYMBOL_GPL(rtrs_iu_post_rdma_write_imm);

	static int rtrs_post_rdma_write_imm_empty(struct rtrs_con *con,
	struct ib_cqe *cqe,
	u32 imm_data,
	struct ib_send_wr *head)
	{
	struct ib_rdma_wr wr;
	struct rtrs_sess *sess = con->sess;
	enum ib_send_flags sflags;

	atomic_dec_if_positive(&con->sq_wr_avail);
	sflags = (atomic_inc_return(&con->wr_cnt) % sess->signal_interval) ?
	0 : IB_SEND_SIGNALED;

	wr = (struct ib_rdma_wr) {
	.wr.wr_cqe = cqe,
	.wr.send_flags = sflags,
	.wr.opcode = IB_WR_RDMA_WRITE_WITH_IMM,
	.wr.ex.imm_data = cpu_to_be32(imm_data),
	};

	return rtrs_post_send(con->qp, head, &wr.wr, NULL);
	}

	static void qp_event_handler(struct ib_event ev, void ctx)
	{
	struct rtrs_con *con = ctx;

	switch (ev->event) {
	case IB_EVENT_COMM_EST:
	rtrs_info(con->sess, "QP event %s (%d) received\n",
	ib_event_msg(ev->event), ev->event);
	rdma_notify(con->cm_id, IB_EVENT_COMM_EST);
	break;
	default:
	rtrs_info(con->sess, "Unhandled QP event %s (%d) received\n",
	ib_event_msg(ev->event), ev->event);
	break;
	}
	}

	static int create_cq(struct rtrs_con *con, int cq_vector, int nr_cqe,
	enum ib_poll_context poll_ctx)
	{
	struct rdma_cm_id *cm_id = con->cm_id;
	struct ib_cq *cq;

	cq = ib_cq_pool_get(cm_id->device, nr_cqe, cq_vector, poll_ctx);
	if (IS_ERR(cq)) {
	rtrs_err(con->sess, "Creating completion queue failed, errno: %ld\n",
	PTR_ERR(cq));
	return PTR_ERR(cq);
	}
	con->cq = cq;
	con->nr_cqe = nr_cqe;

	return 0;
	}

	static int create_qp(struct rtrs_con con, struct ib_pd pd,
	u32 max_send_wr, u32 max_recv_wr, u32 max_sge)
	{
	struct ib_qp_init_attr init_attr = {NULL};
	struct rdma_cm_id *cm_id = con->cm_id;
	int ret;

	init_attr.cap.max_send_wr = max_send_wr;
	init_attr.cap.max_recv_wr = max_recv_wr;
	init_attr.cap.max_recv_sge = 1;
	init_attr.event_handler = qp_event_handler;
	init_attr.qp_context = con;
	init_attr.cap.max_send_sge = max_sge;

	init_attr.qp_type = IB_QPT_RC;
	init_attr.send_cq = con->cq;
	init_attr.recv_cq = con->cq;
	init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;

	ret = rdma_create_qp(cm_id, pd, &init_attr);
	if (ret) {
	rtrs_err(con->sess, "Creating QP failed, err: %d\n", ret);
	return ret;
	}
	con->qp = cm_id->qp;

	return ret;
	}

	int rtrs_cq_qp_create(struct rtrs_sess sess, struct rtrs_con con,
	u32 max_send_sge, int cq_vector, int nr_cqe,
	u32 max_send_wr, u32 max_recv_wr,
	enum ib_poll_context poll_ctx)
	{
	int err;

	err = create_cq(con, cq_vector, nr_cqe, poll_ctx);
	if (err)
	return err;

	err = create_qp(con, sess->dev->ib_pd, max_send_wr, max_recv_wr,
	max_send_sge);
	if (err) {
	ib_cq_pool_put(con->cq, con->nr_cqe);
	con->cq = NULL;
	return err;
	}
	con->sess = sess;

	return 0;
	}
	EXPORT_SYMBOL_GPL(rtrs_cq_qp_create);

	void rtrs_cq_qp_destroy(struct rtrs_con *con)
	{
	if (con->qp) {
	rdma_destroy_qp(con->cm_id);
	con->qp = NULL;
	}
	if (con->cq) {
	ib_cq_pool_put(con->cq, con->nr_cqe);
	con->cq = NULL;
	}
	}
	EXPORT_SYMBOL_GPL(rtrs_cq_qp_destroy);

	static void schedule_hb(struct rtrs_sess *sess)
	{
	queue_delayed_work(sess->hb_wq, &sess->hb_dwork,
	msecs_to_jiffies(sess->hb_interval_ms));
	}

	void rtrs_send_hb_ack(struct rtrs_sess *sess)
	{
	struct rtrs_con *usr_con = sess->con[0];
	u32 imm;
	int err;

	imm = rtrs_to_imm(RTRS_HB_ACK_IMM, 0);
	err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
	NULL);
	if (err) {
	rtrs_err(sess, "send HB ACK failed, errno: %d\n", err);
	sess->hb_err_handler(usr_con);
	return;
	}
	}
	EXPORT_SYMBOL_GPL(rtrs_send_hb_ack);

	static void hb_work(struct work_struct *work)
	{
	struct rtrs_con *usr_con;
	struct rtrs_sess *sess;
	u32 imm;
	int err;

	sess = container_of(to_delayed_work(work), typeof(*sess), hb_dwork);
	usr_con = sess->con[0];

	if (sess->hb_missed_cnt > sess->hb_missed_max) {
	rtrs_err(sess, "HB missed max reached.\n");
	sess->hb_err_handler(usr_con);
	return;
	}
	if (sess->hb_missed_cnt++) {
	/* Reschedule work without sending hb */
	schedule_hb(sess);
	return;
	}

	sess->hb_last_sent = ktime_get();

	imm = rtrs_to_imm(RTRS_HB_MSG_IMM, 0);
	err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
	NULL);
	if (err) {
	rtrs_err(sess, "HB send failed, errno: %d\n", err);
	sess->hb_err_handler(usr_con);
	return;
	}

	schedule_hb(sess);
	}

	void rtrs_init_hb(struct rtrs_sess sess, struct ib_cqe cqe,
	unsigned int interval_ms, unsigned int missed_max,
	void (err_handler)(struct rtrs_con con),
	struct workqueue_struct *wq)
	{
	sess->hb_cqe = cqe;
	sess->hb_interval_ms = interval_ms;
	sess->hb_err_handler = err_handler;
	sess->hb_wq = wq;
	sess->hb_missed_max = missed_max;
	sess->hb_missed_cnt = 0;
	INIT_DELAYED_WORK(&sess->hb_dwork, hb_work);
	}
	EXPORT_SYMBOL_GPL(rtrs_init_hb);

	void rtrs_start_hb(struct rtrs_sess *sess)
	{
	schedule_hb(sess);
	}
	EXPORT_SYMBOL_GPL(rtrs_start_hb);

	void rtrs_stop_hb(struct rtrs_sess *sess)
	{
	cancel_delayed_work_sync(&sess->hb_dwork);
	sess->hb_missed_cnt = 0;
	}
	EXPORT_SYMBOL_GPL(rtrs_stop_hb);

	static int rtrs_str_gid_to_sockaddr(const char *addr, size_t len,
	short port, struct sockaddr_storage *dst)
	{
	struct sockaddr_ib dst_ib = (struct sockaddr_ib )dst;
	int ret;

	/*
	* We can use some of the IPv6 functions since GID is a valid
	* IPv6 address format
	*/
	ret = in6_pton(addr, len, dst_ib->sib_addr.sib_raw, '\0', NULL);
	if (ret == 0)
	return -EINVAL;

	dst_ib->sib_family = AF_IB;
	/*
	* Use the same TCP server port number as the IB service ID
	* on the IB port space range
	*/
	dst_ib->sib_sid = cpu_to_be64(RDMA_IB_IP_PS_IB \| port);
	dst_ib->sib_sid_mask = cpu_to_be64(0xffffffffffffffffULL);
	dst_ib->sib_pkey = cpu_to_be16(0xffff);

	return 0;
	}

	/**
	* rtrs_str_to_sockaddr() - Convert rtrs address string to sockaddr
	* @addr: String representation of an addr (IPv4, IPv6 or IB GID):
	* - "ip:192.168.1.1"
	* - "ip:fe80::200:5aee:feaa:20a2"
	* - "gid:fe80::200:5aee:feaa:20a2"
	* @len: String address length
	* @port: Destination port
	* @dst: Destination sockaddr structure
	*
	* Returns 0 if conversion successful. Non-zero on error.
	*/
	static int rtrs_str_to_sockaddr(const char *addr, size_t len,
	u16 port, struct sockaddr_storage *dst)
	{
	if (strncmp(addr, "gid:", 4) == 0) {
	return rtrs_str_gid_to_sockaddr(addr + 4, len - 4, port, dst);
	} else if (strncmp(addr, "ip:", 3) == 0) {
	char port_str[8];
	char *cpy;
	int err;

	snprintf(port_str, sizeof(port_str), "%u", port);
	cpy = kstrndup(addr + 3, len - 3, GFP_KERNEL);
	err = cpy ? inet_pton_with_scope(&init_net, AF_UNSPEC,
	cpy, port_str, dst) : -ENOMEM;
	kfree(cpy);

	return err;
	}
	return -EPROTONOSUPPORT;
	}

	/**
	* sockaddr_to_str() - convert sockaddr to a string.
	* @addr: the sockadddr structure to be converted.
	* @buf: string containing socket addr.
	* @len: string length.
	*
	* The return value is the number of characters written into buf not
	* including the trailing '\0'. If len is == 0 the function returns 0..
	*/
	int sockaddr_to_str(const struct sockaddr addr, char buf, size_t len)
	{

	switch (addr->sa_family) {
	case AF_IB:
	return scnprintf(buf, len, "gid:%pI6",
	&((struct sockaddr_ib *)addr)->sib_addr.sib_raw);
	case AF_INET:
	return scnprintf(buf, len, "ip:%pI4",
	&((struct sockaddr_in *)addr)->sin_addr);
	case AF_INET6:
	return scnprintf(buf, len, "ip:%pI6c",
	&((struct sockaddr_in6 *)addr)->sin6_addr);
	}
	return scnprintf(buf, len, "<invalid address family>");
	}
	EXPORT_SYMBOL(sockaddr_to_str);

	/**
	* rtrs_addr_to_str() - convert rtrs_addr to a string "src@dst"
	* @addr: the rtrs_addr structure to be converted
	* @buf: string containing source and destination addr of a path
	* separated by '@' I.e. "ip:1.1.1.1@ip:1.1.1.2"
	* "ip:1.1.1.1@ip:1.1.1.2".
	* @len: string length
	*
	* The return value is the number of characters written into buf not
	* including the trailing '\0'.
	*/
	int rtrs_addr_to_str(const struct rtrs_addr addr, char buf, size_t len)
	{
	int cnt;

	cnt = sockaddr_to_str((struct sockaddr *)addr->src,
	buf, len);
	cnt += scnprintf(buf + cnt, len - cnt, "@");
	sockaddr_to_str((struct sockaddr *)addr->dst,
	buf + cnt, len - cnt);
	return cnt;
	}
	EXPORT_SYMBOL(rtrs_addr_to_str);

	/**
	* rtrs_addr_to_sockaddr() - convert path string "src,dst" or "src@dst"
	* to sockaddreses
	* @str: string containing source and destination addr of a path
	* separated by ',' or '@' I.e. "ip:1.1.1.1,ip:1.1.1.2" or
	* "ip:1.1.1.1@ip:1.1.1.2". If str contains only one address it's
	* considered to be destination.
	* @len: string length
	* @port: Destination port number.
	* @addr: will be set to the source/destination address or to NULL
	* if str doesn't contain any source address.
	*
	* Returns zero if conversion successful. Non-zero otherwise.
	*/
	int rtrs_addr_to_sockaddr(const char *str, size_t len, u16 port,
	struct rtrs_addr *addr)
	{
	const char *d;

	d = strchr(str, ',');
	if (!d)
	d = strchr(str, '@');
	if (d) {
	if (rtrs_str_to_sockaddr(str, d - str, 0, addr->src))
	return -EINVAL;
	d += 1;
	len -= d - str;
	str = d;

	} else {
	addr->src = NULL;
	}
	return rtrs_str_to_sockaddr(str, len, port, addr->dst);
	}
	EXPORT_SYMBOL(rtrs_addr_to_sockaddr);

	void rtrs_rdma_dev_pd_init(enum ib_pd_flags pd_flags,
	struct rtrs_rdma_dev_pd *pool)
	{
	WARN_ON(pool->ops && (!pool->ops->alloc ^ !pool->ops->free));
	INIT_LIST_HEAD(&pool->list);
	mutex_init(&pool->mutex);
	pool->pd_flags = pd_flags;
	}
	EXPORT_SYMBOL(rtrs_rdma_dev_pd_init);

	void rtrs_rdma_dev_pd_deinit(struct rtrs_rdma_dev_pd *pool)
	{
	mutex_destroy(&pool->mutex);
	WARN_ON(!list_empty(&pool->list));
	}
	EXPORT_SYMBOL(rtrs_rdma_dev_pd_deinit);

	static void dev_free(struct kref *ref)
	{
	struct rtrs_rdma_dev_pd *pool;
	struct rtrs_ib_dev *dev;

	dev = container_of(ref, typeof(*dev), ref);
	pool = dev->pool;

	mutex_lock(&pool->mutex);
	list_del(&dev->entry);
	mutex_unlock(&pool->mutex);

	if (pool->ops && pool->ops->deinit)
	pool->ops->deinit(dev);

	ib_dealloc_pd(dev->ib_pd);

	if (pool->ops && pool->ops->free)
	pool->ops->free(dev);
	else
	kfree(dev);
	}

	int rtrs_ib_dev_put(struct rtrs_ib_dev *dev)
	{
	return kref_put(&dev->ref, dev_free);
	}
	EXPORT_SYMBOL(rtrs_ib_dev_put);

	static int rtrs_ib_dev_get(struct rtrs_ib_dev *dev)
	{
	return kref_get_unless_zero(&dev->ref);
	}

	struct rtrs_ib_dev *
	rtrs_ib_dev_find_or_add(struct ib_device *ib_dev,
	struct rtrs_rdma_dev_pd *pool)
	{
	struct rtrs_ib_dev *dev;

	mutex_lock(&pool->mutex);
	list_for_each_entry(dev, &pool->list, entry) {
	if (dev->ib_dev->node_guid == ib_dev->node_guid &&
	rtrs_ib_dev_get(dev))
	goto out_unlock;
	}
	mutex_unlock(&pool->mutex);
	if (pool->ops && pool->ops->alloc)
	dev = pool->ops->alloc();
	else
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (IS_ERR_OR_NULL(dev))
	goto out_err;

	kref_init(&dev->ref);
	dev->pool = pool;
	dev->ib_dev = ib_dev;
	dev->ib_pd = ib_alloc_pd(ib_dev, pool->pd_flags);
	if (IS_ERR(dev->ib_pd))
	goto out_free_dev;

	if (pool->ops && pool->ops->init && pool->ops->init(dev))
	goto out_free_pd;

	mutex_lock(&pool->mutex);
	list_add(&dev->entry, &pool->list);
	out_unlock:
	mutex_unlock(&pool->mutex);
	return dev;

	out_free_pd:
	ib_dealloc_pd(dev->ib_pd);
	out_free_dev:
	if (pool->ops && pool->ops->free)
	pool->ops->free(dev);
	else
	kfree(dev);
	out_err:
	return NULL;
	}
	EXPORT_SYMBOL(rtrs_ib_dev_find_or_add);