rdma/siw: connection management

Broken up commit to add the Soft iWarp RDMA driver.
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/siw/siw_cm.c

+// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
+
+/* Authors: Bernard Metzler <bmt@zurich.ibm.com> */
+/*          Fredy Neeser */
+/*          Greg Joyce <greg@opengridcomputing.com> */
+/* Copyright (c) 2008-2019, IBM Corporation */
+/* Copyright (c) 2017, Open Grid Computing, Inc. */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/inetdevice.h>
+#include <net/addrconf.h>
+#include <linux/workqueue.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <linux/inet.h>
+#include <linux/tcp.h>
+
+#include <rdma/iw_cm.h>
+#include <rdma/ib_verbs.h>
+#include <rdma/ib_user_verbs.h>
+
+#include "siw.h"
+#include "siw_cm.h"
+
+/*
+ * Set to any combination of
+ * MPA_V2_RDMA_NO_RTR, MPA_V2_RDMA_READ_RTR, MPA_V2_RDMA_WRITE_RTR
+ */
+static __be16 rtr_type = MPA_V2_RDMA_READ_RTR | MPA_V2_RDMA_WRITE_RTR;
+static const bool relaxed_ird_negotiation = 1;
+
+static void siw_cm_llp_state_change(struct sock *s);
+static void siw_cm_llp_data_ready(struct sock *s);
+static void siw_cm_llp_write_space(struct sock *s);
+static void siw_cm_llp_error_report(struct sock *s);
+static int siw_cm_upcall(struct siw_cep *cep, enum iw_cm_event_type reason,
+			 int status);
+
+static void siw_sk_assign_cm_upcalls(struct sock *sk)
+{
+	write_lock_bh(&sk->sk_callback_lock);
+	sk->sk_state_change = siw_cm_llp_state_change;
+	sk->sk_data_ready = siw_cm_llp_data_ready;
+	sk->sk_write_space = siw_cm_llp_write_space;
+	sk->sk_error_report = siw_cm_llp_error_report;
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void siw_sk_save_upcalls(struct sock *sk)
+{
+	struct siw_cep *cep = sk_to_cep(sk);
+
+	write_lock_bh(&sk->sk_callback_lock);
+	cep->sk_state_change = sk->sk_state_change;
+	cep->sk_data_ready = sk->sk_data_ready;
+	cep->sk_write_space = sk->sk_write_space;
+	cep->sk_error_report = sk->sk_error_report;
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void siw_sk_restore_upcalls(struct sock *sk, struct siw_cep *cep)
+{
+	sk->sk_state_change = cep->sk_state_change;
+	sk->sk_data_ready = cep->sk_data_ready;
+	sk->sk_write_space = cep->sk_write_space;
+	sk->sk_error_report = cep->sk_error_report;
+	sk->sk_user_data = NULL;
+}
+
+static void siw_qp_socket_assoc(struct siw_cep *cep, struct siw_qp *qp)
+{
+	struct socket *s = cep->sock;
+	struct sock *sk = s->sk;
+
+	write_lock_bh(&sk->sk_callback_lock);
+
+	qp->attrs.sk = s;
+	sk->sk_data_ready = siw_qp_llp_data_ready;
+	sk->sk_write_space = siw_qp_llp_write_space;
+
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void siw_socket_disassoc(struct socket *s)
+{
+	struct sock *sk = s->sk;
+	struct siw_cep *cep;
+
+	if (sk) {
+		write_lock_bh(&sk->sk_callback_lock);
+		cep = sk_to_cep(sk);
+		if (cep) {
+			siw_sk_restore_upcalls(sk, cep);
+			siw_cep_put(cep);
+		} else {
+			pr_warn("siw: cannot restore sk callbacks: no ep\n");
+		}
+		write_unlock_bh(&sk->sk_callback_lock);
+	} else {
+		pr_warn("siw: cannot restore sk callbacks: no sk\n");
+	}
+}
+
+static void siw_rtr_data_ready(struct sock *sk)
+{
+	struct siw_cep *cep;
+	struct siw_qp *qp = NULL;
+	read_descriptor_t rd_desc;
+
+	read_lock(&sk->sk_callback_lock);
+
+	cep = sk_to_cep(sk);
+	if (!cep) {
+		WARN(1, "No connection endpoint\n");
+		goto out;
+	}
+	qp = sk_to_qp(sk);
+
+	memset(&rd_desc, 0, sizeof(rd_desc));
+	rd_desc.arg.data = qp;
+	rd_desc.count = 1;
+
+	tcp_read_sock(sk, &rd_desc, siw_tcp_rx_data);
+	/*
+	 * Check if first frame was successfully processed.
+	 * Signal connection full establishment if yes.
+	 * Failed data processing would have already scheduled
+	 * connection drop.
+	 */
+	if (!qp->rx_stream.rx_suspend)
+		siw_cm_upcall(cep, IW_CM_EVENT_ESTABLISHED, 0);
+out:
+	read_unlock(&sk->sk_callback_lock);
+	if (qp)
+		siw_qp_socket_assoc(cep, qp);
+}
+
+static void siw_sk_assign_rtr_upcalls(struct siw_cep *cep)
+{
+	struct sock *sk = cep->sock->sk;
+
+	write_lock_bh(&sk->sk_callback_lock);
+	sk->sk_data_ready = siw_rtr_data_ready;
+	sk->sk_write_space = siw_qp_llp_write_space;
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void siw_cep_socket_assoc(struct siw_cep *cep, struct socket *s)
+{
+	cep->sock = s;
+	siw_cep_get(cep);
+	s->sk->sk_user_data = cep;
+
+	siw_sk_save_upcalls(s->sk);
+	siw_sk_assign_cm_upcalls(s->sk);
+}
+
+static struct siw_cep *siw_cep_alloc(struct siw_device *sdev)
+{
+	struct siw_cep *cep = kzalloc(sizeof(*cep), GFP_KERNEL);
+	unsigned long flags;
+
+	if (!cep)
+		return NULL;
+
+	INIT_LIST_HEAD(&cep->listenq);
+	INIT_LIST_HEAD(&cep->devq);
+	INIT_LIST_HEAD(&cep->work_freelist);
+
+	kref_init(&cep->ref);
+	cep->state = SIW_EPSTATE_IDLE;
+	init_waitqueue_head(&cep->waitq);
+	spin_lock_init(&cep->lock);
+	cep->sdev = sdev;
+	cep->enhanced_rdma_conn_est = false;
+
+	spin_lock_irqsave(&sdev->lock, flags);
+	list_add_tail(&cep->devq, &sdev->cep_list);
+	spin_unlock_irqrestore(&sdev->lock, flags);
+
+	siw_dbg_cep(cep, "new endpoint\n");
+	return cep;
+}
+
+static void siw_cm_free_work(struct siw_cep *cep)
+{
+	struct list_head *w, *tmp;
+	struct siw_cm_work *work;
+
+	list_for_each_safe(w, tmp, &cep->work_freelist) {
+		work = list_entry(w, struct siw_cm_work, list);
+		list_del(&work->list);
+		kfree(work);
+	}
+}
+
+static void siw_cancel_mpatimer(struct siw_cep *cep)
+{
+	spin_lock_bh(&cep->lock);
+	if (cep->mpa_timer) {
+		if (cancel_delayed_work(&cep->mpa_timer->work)) {
+			siw_cep_put(cep);
+			kfree(cep->mpa_timer); /* not needed again */
+		}
+		cep->mpa_timer = NULL;
+	}
+	spin_unlock_bh(&cep->lock);
+}
+
+static void siw_put_work(struct siw_cm_work *work)
+{
+	INIT_LIST_HEAD(&work->list);
+	spin_lock_bh(&work->cep->lock);
+	list_add(&work->list, &work->cep->work_freelist);
+	spin_unlock_bh(&work->cep->lock);
+}
+
+static void siw_cep_set_inuse(struct siw_cep *cep)
+{
+	unsigned long flags;
+	int rv;
+retry:
+	spin_lock_irqsave(&cep->lock, flags);
+
+	if (cep->in_use) {
+		spin_unlock_irqrestore(&cep->lock, flags);
+		rv = wait_event_interruptible(cep->waitq, !cep->in_use);
+		if (signal_pending(current))
+			flush_signals(current);
+		goto retry;
+	} else {
+		cep->in_use = 1;
+		spin_unlock_irqrestore(&cep->lock, flags);
+	}
+}
+
+static void siw_cep_set_free(struct siw_cep *cep)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cep->lock, flags);
+	cep->in_use = 0;
+	spin_unlock_irqrestore(&cep->lock, flags);
+
+	wake_up(&cep->waitq);
+}
+
+static void __siw_cep_dealloc(struct kref *ref)
+{
+	struct siw_cep *cep = container_of(ref, struct siw_cep, ref);
+	struct siw_device *sdev = cep->sdev;
+	unsigned long flags;
+
+	WARN_ON(cep->listen_cep);
+
+	/* kfree(NULL) is safe */
+	kfree(cep->mpa.pdata);
+	spin_lock_bh(&cep->lock);
+	if (!list_empty(&cep->work_freelist))
+		siw_cm_free_work(cep);
+	spin_unlock_bh(&cep->lock);
+
+	spin_lock_irqsave(&sdev->lock, flags);
+	list_del(&cep->devq);
+	spin_unlock_irqrestore(&sdev->lock, flags);
+
+	siw_dbg_cep(cep, "free endpoint\n");
+	kfree(cep);
+}
+
+static struct siw_cm_work *siw_get_work(struct siw_cep *cep)
+{
+	struct siw_cm_work *work = NULL;
+
+	spin_lock_bh(&cep->lock);
+	if (!list_empty(&cep->work_freelist)) {
+		work = list_entry(cep->work_freelist.next, struct siw_cm_work,
+				  list);
+		list_del_init(&work->list);
+	}
+	spin_unlock_bh(&cep->lock);
+	return work;
+}
+
+static int siw_cm_alloc_work(struct siw_cep *cep, int num)
+{
+	struct siw_cm_work *work;
+
+	while (num--) {
+		work = kmalloc(sizeof(*work), GFP_KERNEL);
+		if (!work) {
+			if (!(list_empty(&cep->work_freelist)))
+				siw_cm_free_work(cep);
+			return -ENOMEM;
+		}
+		work->cep = cep;
+		INIT_LIST_HEAD(&work->list);
+		list_add(&work->list, &cep->work_freelist);
+	}
+	return 0;
+}
+
+/*
+ * siw_cm_upcall()
+ *
+ * Upcall to IWCM to inform about async connection events
+ */
+static int siw_cm_upcall(struct siw_cep *cep, enum iw_cm_event_type reason,
+			 int status)
+{
+	struct iw_cm_event event;
+	struct iw_cm_id *id;
+
+	memset(&event, 0, sizeof(event));
+	event.status = status;
+	event.event = reason;
+
+	if (reason == IW_CM_EVENT_CONNECT_REQUEST) {
+		event.provider_data = cep;
+		id = cep->listen_cep->cm_id;
+	} else {
+		id = cep->cm_id;
+	}
+	/* Signal IRD and ORD */
+	if (reason == IW_CM_EVENT_ESTABLISHED ||
+	    reason == IW_CM_EVENT_CONNECT_REPLY) {
+		/* Signal negotiated IRD/ORD values we will use */
+		event.ird = cep->ird;
+		event.ord = cep->ord;
+	} else if (reason == IW_CM_EVENT_CONNECT_REQUEST) {
+		event.ird = cep->ord;
+		event.ord = cep->ird;
+	}
+	/* Signal private data and address information */
+	if (reason == IW_CM_EVENT_CONNECT_REQUEST ||
+	    reason == IW_CM_EVENT_CONNECT_REPLY) {
+		u16 pd_len = be16_to_cpu(cep->mpa.hdr.params.pd_len);
+
+		if (pd_len) {
+			/*
+			 * hand over MPA private data
+			 */
+			event.private_data_len = pd_len;
+			event.private_data = cep->mpa.pdata;
+
+			/* Hide MPA V2 IRD/ORD control */
+			if (cep->enhanced_rdma_conn_est) {
+				event.private_data_len -=
+					sizeof(struct mpa_v2_data);
+				event.private_data +=
+					sizeof(struct mpa_v2_data);
+			}
+		}
+		getname_local(cep->sock, &event.local_addr);
+		getname_peer(cep->sock, &event.remote_addr);
+	}
+	siw_dbg_cep(cep, "[QP %u]: id 0x%p, reason=%d, status=%d\n",
+		    cep->qp ? qp_id(cep->qp) : -1, id, reason, status);
+
+	return id->event_handler(id, &event);
+}
+
+/*
+ * siw_qp_cm_drop()
+ *
+ * Drops established LLP connection if present and not already
+ * scheduled for dropping. Called from user context, SQ workqueue
+ * or receive IRQ. Caller signals if socket can be immediately
+ * closed (basically, if not in IRQ).
+ */
+void siw_qp_cm_drop(struct siw_qp *qp, int schedule)
+{
+	struct siw_cep *cep = qp->cep;
+
+	qp->rx_stream.rx_suspend = 1;
+	qp->tx_ctx.tx_suspend = 1;
+
+	if (!qp->cep)
+		return;
+
+	if (schedule) {
+		siw_cm_queue_work(cep, SIW_CM_WORK_CLOSE_LLP);
+	} else {
+		siw_cep_set_inuse(cep);
+
+		if (cep->state == SIW_EPSTATE_CLOSED) {
+			siw_dbg_cep(cep, "already closed\n");
+			goto out;
+		}
+		siw_dbg_cep(cep, "immediate close, state %d\n", cep->state);
+
+		if (qp->term_info.valid)
+			siw_send_terminate(qp);
+
+		if (cep->cm_id) {
+			switch (cep->state) {
+			case SIW_EPSTATE_AWAIT_MPAREP:
+				siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY,
+					      -EINVAL);
+				break;
+
+			case SIW_EPSTATE_RDMA_MODE:
+				siw_cm_upcall(cep, IW_CM_EVENT_CLOSE, 0);
+				break;
+
+			case SIW_EPSTATE_IDLE:
+			case SIW_EPSTATE_LISTENING:
+			case SIW_EPSTATE_CONNECTING:
+			case SIW_EPSTATE_AWAIT_MPAREQ:
+			case SIW_EPSTATE_RECVD_MPAREQ:
+			case SIW_EPSTATE_CLOSED:
+			default:
+				break;
+			}
+			cep->cm_id->rem_ref(cep->cm_id);
+			cep->cm_id = NULL;
+			siw_cep_put(cep);
+		}
+		cep->state = SIW_EPSTATE_CLOSED;
+
+		if (cep->sock) {
+			siw_socket_disassoc(cep->sock);
+			/*
+			 * Immediately close socket
+			 */
+			sock_release(cep->sock);
+			cep->sock = NULL;
+		}
+		if (cep->qp) {
+			cep->qp = NULL;
+			siw_qp_put(qp);
+		}
+out:
+		siw_cep_set_free(cep);
+	}
+}
+
+void siw_cep_put(struct siw_cep *cep)
+{
+	WARN_ON(kref_read(&cep->ref) < 1);
+	kref_put(&cep->ref, __siw_cep_dealloc);
+}
+
+void siw_cep_get(struct siw_cep *cep)
+{
+	kref_get(&cep->ref);
+}
+
+/*
+ * Expects params->pd_len in host byte order
+ */
+static int siw_send_mpareqrep(struct siw_cep *cep, const void *pdata, u8 pd_len)
+{
+	struct socket *s = cep->sock;
+	struct mpa_rr *rr = &cep->mpa.hdr;
+	struct kvec iov[3];
+	struct msghdr msg;
+	int rv;
+	int iovec_num = 0;
+	int mpa_len;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov[iovec_num].iov_base = rr;
+	iov[iovec_num].iov_len = sizeof(*rr);
+	mpa_len = sizeof(*rr);
+
+	if (cep->enhanced_rdma_conn_est) {
+		iovec_num++;
+		iov[iovec_num].iov_base = &cep->mpa.v2_ctrl;
+		iov[iovec_num].iov_len = sizeof(cep->mpa.v2_ctrl);
+		mpa_len += sizeof(cep->mpa.v2_ctrl);
+	}
+	if (pd_len) {
+		iovec_num++;
+		iov[iovec_num].iov_base = (char *)pdata;
+		iov[iovec_num].iov_len = pd_len;
+		mpa_len += pd_len;
+	}
+	if (cep->enhanced_rdma_conn_est)
+		pd_len += sizeof(cep->mpa.v2_ctrl);
+
+	rr->params.pd_len = cpu_to_be16(pd_len);
+
+	rv = kernel_sendmsg(s, &msg, iov, iovec_num + 1, mpa_len);
+
+	return rv < 0 ? rv : 0;
+}
+
+/*
+ * Receive MPA Request/Reply header.
+ *
+ * Returns 0 if complete MPA Request/Reply header including
+ * eventual private data was received. Returns -EAGAIN if
+ * header was partially received or negative error code otherwise.
+ *
+ * Context: May be called in process context only
+ */
+static int siw_recv_mpa_rr(struct siw_cep *cep)
+{
+	struct mpa_rr *hdr = &cep->mpa.hdr;
+	struct socket *s = cep->sock;
+	u16 pd_len;
+	int rcvd, to_rcv;
+
+	if (cep->mpa.bytes_rcvd < sizeof(struct mpa_rr)) {
+		rcvd = ksock_recv(s, (char *)hdr + cep->mpa.bytes_rcvd,
+				  sizeof(struct mpa_rr) - cep->mpa.bytes_rcvd,
+				  0);
+		if (rcvd <= 0)
+			return -ECONNABORTED;
+
+		cep->mpa.bytes_rcvd += rcvd;
+
+		if (cep->mpa.bytes_rcvd < sizeof(struct mpa_rr))
+			return -EAGAIN;
+
+		if (be16_to_cpu(hdr->params.pd_len) > MPA_MAX_PRIVDATA)
+			return -EPROTO;
+	}
+	pd_len = be16_to_cpu(hdr->params.pd_len);
+
+	/*
+	 * At least the MPA Request/Reply header (frame not including
+	 * private data) has been received.
+	 * Receive (or continue receiving) any private data.
+	 */
+	to_rcv = pd_len - (cep->mpa.bytes_rcvd - sizeof(struct mpa_rr));
+
+	if (!to_rcv) {
+		/*
+		 * We must have hdr->params.pd_len == 0 and thus received a
+		 * complete MPA Request/Reply frame.
+		 * Check against peer protocol violation.
+		 */
+		u32 word;
+
+		rcvd = ksock_recv(s, (char *)&word, sizeof(word), MSG_DONTWAIT);
+		if (rcvd == -EAGAIN)
+			return 0;
+
+		if (rcvd == 0) {
+			siw_dbg_cep(cep, "peer EOF\n");
+			return -EPIPE;
+		}
+		if (rcvd < 0) {
+			siw_dbg_cep(cep, "error: %d\n", rcvd);
+			return rcvd;
+		}
+		siw_dbg_cep(cep, "peer sent extra data: %d\n", rcvd);
+
+		return -EPROTO;
+	}
+
+	/*
+	 * At this point, we must have hdr->params.pd_len != 0.
+	 * A private data buffer gets allocated if hdr->params.pd_len != 0.
+	 */
+	if (!cep->mpa.pdata) {
+		cep->mpa.pdata = kmalloc(pd_len + 4, GFP_KERNEL);
+		if (!cep->mpa.pdata)
+			return -ENOMEM;
+	}
+	rcvd = ksock_recv(
+		s, cep->mpa.pdata + cep->mpa.bytes_rcvd - sizeof(struct mpa_rr),
+		to_rcv + 4, MSG_DONTWAIT);
+
+	if (rcvd < 0)
+		return rcvd;
+
+	if (rcvd > to_rcv)
+		return -EPROTO;
+
+	cep->mpa.bytes_rcvd += rcvd;
+
+	if (to_rcv == rcvd) {
+		siw_dbg_cep(cep, "%d bytes private data received\n", pd_len);
+		return 0;
+	}
+	return -EAGAIN;
+}
+
+/*
+ * siw_proc_mpareq()
+ *
+ * Read MPA Request from socket and signal new connection to IWCM
+ * if success. Caller must hold lock on corresponding listening CEP.
+ */
+static int siw_proc_mpareq(struct siw_cep *cep)
+{
+	struct mpa_rr *req;
+	int version, rv;
+	u16 pd_len;
+
+	rv = siw_recv_mpa_rr(cep);
+	if (rv)
+		return rv;
+
+	req = &cep->mpa.hdr;
+
+	version = __mpa_rr_revision(req->params.bits);
+	pd_len = be16_to_cpu(req->params.pd_len);
+
+	if (version > MPA_REVISION_2)
+		/* allow for 0, 1, and 2 only */
+		return -EPROTO;
+
+	if (memcmp(req->key, MPA_KEY_REQ, 16))
+		return -EPROTO;
+
+	/* Prepare for sending MPA reply */
+	memcpy(req->key, MPA_KEY_REP, 16);
+
+	if (version == MPA_REVISION_2 &&
+	    (req->params.bits & MPA_RR_FLAG_ENHANCED)) {
+		/*
+		 * MPA version 2 must signal IRD/ORD values and P2P mode
+		 * in private data if header flag MPA_RR_FLAG_ENHANCED
+		 * is set.
+		 */
+		if (pd_len < sizeof(struct mpa_v2_data))
+			goto reject_conn;
+
+		cep->enhanced_rdma_conn_est = true;
+	}
+
+	/* MPA Markers: currently not supported. Marker TX to be added. */
+	if (req->params.bits & MPA_RR_FLAG_MARKERS)
+		goto reject_conn;
+
+	if (req->params.bits & MPA_RR_FLAG_CRC) {
+		/*
+		 * RFC 5044, page 27: CRC MUST be used if peer requests it.
+		 * siw specific: 'mpa_crc_strict' parameter to reject
+		 * connection with CRC if local CRC off enforced by
+		 * 'mpa_crc_strict' module parameter.
+		 */
+		if (!mpa_crc_required && mpa_crc_strict)
+			goto reject_conn;
+
+		/* Enable CRC if requested by module parameter */
+		if (mpa_crc_required)
+			req->params.bits |= MPA_RR_FLAG_CRC;
+	}
+	if (cep->enhanced_rdma_conn_est) {
+		struct mpa_v2_data *v2 = (struct mpa_v2_data *)cep->mpa.pdata;
+
+		/*
+		 * Peer requested ORD becomes requested local IRD,
+		 * peer requested IRD becomes requested local ORD.
+		 * IRD and ORD get limited by global maximum values.
+		 */
+		cep->ord = ntohs(v2->ird) & MPA_IRD_ORD_MASK;
+		cep->ord = min(cep->ord, SIW_MAX_ORD_QP);
+		cep->ird = ntohs(v2->ord) & MPA_IRD_ORD_MASK;
+		cep->ird = min(cep->ird, SIW_MAX_IRD_QP);
+
+		/* May get overwritten by locally negotiated values */
+		cep->mpa.v2_ctrl.ird = htons(cep->ird);
+		cep->mpa.v2_ctrl.ord = htons(cep->ord);
+
+		/*
+		 * Support for peer sent zero length Write or Read to
+		 * let local side enter RTS. Writes are preferred.
+		 * Sends would require pre-posting a Receive and are
+		 * not supported.
+		 * Propose zero length Write if none of Read and Write
+		 * is indicated.
+		 */
+		if (v2->ird & MPA_V2_PEER_TO_PEER) {
+			cep->mpa.v2_ctrl.ird |= MPA_V2_PEER_TO_PEER;
+
+			if (v2->ord & MPA_V2_RDMA_WRITE_RTR)
+				cep->mpa.v2_ctrl.ord |= MPA_V2_RDMA_WRITE_RTR;
+			else if (v2->ord & MPA_V2_RDMA_READ_RTR)
+				cep->mpa.v2_ctrl.ord |= MPA_V2_RDMA_READ_RTR;
+			else
+				cep->mpa.v2_ctrl.ord |= MPA_V2_RDMA_WRITE_RTR;
+		}
+	}
+
+	cep->state = SIW_EPSTATE_RECVD_MPAREQ;
+
+	/* Keep reference until IWCM accepts/rejects */
+	siw_cep_get(cep);
+	rv = siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REQUEST, 0);
+	if (rv)
+		siw_cep_put(cep);
+
+	return rv;
+
+reject_conn:
+	siw_dbg_cep(cep, "reject: crc %d:%d:%d, m %d:%d\n",
+		    req->params.bits & MPA_RR_FLAG_CRC ? 1 : 0,
+		    mpa_crc_required, mpa_crc_strict,
+		    req->params.bits & MPA_RR_FLAG_MARKERS ? 1 : 0, 0);
+
+	req->params.bits &= ~MPA_RR_FLAG_MARKERS;
+	req->params.bits |= MPA_RR_FLAG_REJECT;
+
+	if (!mpa_crc_required && mpa_crc_strict)
+		req->params.bits &= ~MPA_RR_FLAG_CRC;
+
+	if (pd_len)
+		kfree(cep->mpa.pdata);
+
+	cep->mpa.pdata = NULL;
+
+	siw_send_mpareqrep(cep, NULL, 0);
+
+	return -EOPNOTSUPP;
+}
+
+static int siw_proc_mpareply(struct siw_cep *cep)
+{
+	struct siw_qp_attrs qp_attrs;
+	enum siw_qp_attr_mask qp_attr_mask;
+	struct siw_qp *qp = cep->qp;
+	struct mpa_rr *rep;
+	int rv;
+	u16 rep_ord;
+	u16 rep_ird;
+	bool ird_insufficient = false;
+	enum mpa_v2_ctrl mpa_p2p_mode = MPA_V2_RDMA_NO_RTR;
+
+	rv = siw_recv_mpa_rr(cep);
+	if (rv != -EAGAIN)
+		siw_cancel_mpatimer(cep);
+	if (rv)
+		goto out_err;
+
+	rep = &cep->mpa.hdr;
+
+	if (__mpa_rr_revision(rep->params.bits) > MPA_REVISION_2) {
+		/* allow for 0, 1,  and 2 only */
+		rv = -EPROTO;
+		goto out_err;
+	}
+	if (memcmp(rep->key, MPA_KEY_REP, 16)) {
+		siw_init_terminate(qp, TERM_ERROR_LAYER_LLP, LLP_ETYPE_MPA,
+				   LLP_ECODE_INVALID_REQ_RESP, 0);
+		siw_send_terminate(qp);
+		rv = -EPROTO;
+		goto out_err;
+	}
+	if (rep->params.bits & MPA_RR_FLAG_REJECT) {
+		siw_dbg_cep(cep, "got mpa reject\n");
+		siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, -ECONNRESET);
+
+		return -ECONNRESET;
+	}
+	if (try_gso && rep->params.bits & MPA_RR_FLAG_GSO_EXP) {
+		siw_dbg_cep(cep, "peer allows GSO on TX\n");
+		qp->tx_ctx.gso_seg_limit = 0;
+	}
+	if ((rep->params.bits & MPA_RR_FLAG_MARKERS) ||
+	    (mpa_crc_required && !(rep->params.bits & MPA_RR_FLAG_CRC)) ||
+	    (mpa_crc_strict && !mpa_crc_required &&
+	     (rep->params.bits & MPA_RR_FLAG_CRC))) {
+		siw_dbg_cep(cep, "reply unsupp: crc %d:%d:%d, m %d:%d\n",
+			    rep->params.bits & MPA_RR_FLAG_CRC ? 1 : 0,
+			    mpa_crc_required, mpa_crc_strict,
+			    rep->params.bits & MPA_RR_FLAG_MARKERS ? 1 : 0, 0);
+
+		siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, -ECONNREFUSED);
+
+		return -EINVAL;
+	}
+	if (cep->enhanced_rdma_conn_est) {
+		struct mpa_v2_data *v2;
+
+		if (__mpa_rr_revision(rep->params.bits) < MPA_REVISION_2 ||
+		    !(rep->params.bits & MPA_RR_FLAG_ENHANCED)) {
+			/*
+			 * Protocol failure: The responder MUST reply with
+			 * MPA version 2 and MUST set MPA_RR_FLAG_ENHANCED.
+			 */
+			siw_dbg_cep(cep, "mpa reply error: vers %d, enhcd %d\n",
+				    __mpa_rr_revision(rep->params.bits),
+				    rep->params.bits & MPA_RR_FLAG_ENHANCED ?
+					    1 :
+					    0);
+
+			siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY,
+				      -ECONNRESET);
+			return -EINVAL;
+		}
+		v2 = (struct mpa_v2_data *)cep->mpa.pdata;
+		rep_ird = ntohs(v2->ird) & MPA_IRD_ORD_MASK;
+		rep_ord = ntohs(v2->ord) & MPA_IRD_ORD_MASK;
+
+		if (cep->ird < rep_ord &&
+		    (relaxed_ird_negotiation == false ||
+		     rep_ord > cep->sdev->attrs.max_ird)) {
+			siw_dbg_cep(cep, "ird %d, rep_ord %d, max_ord %d\n",
+				    cep->ird, rep_ord,
+				    cep->sdev->attrs.max_ord);
+			ird_insufficient = true;
+		}
+		if (cep->ord > rep_ird && relaxed_ird_negotiation == false) {
+			siw_dbg_cep(cep, "ord %d, rep_ird %d\n", cep->ord,
+				    rep_ird);
+			ird_insufficient = true;
+		}
+		/*
+		 * Always report negotiated peer values to user,
+		 * even if IRD/ORD negotiation failed
+		 */
+		cep->ird = rep_ord;
+		cep->ord = rep_ird;
+
+		if (ird_insufficient) {
+			/*
+			 * If the initiator IRD is insuffient for the
+			 * responder ORD, send a TERM.
+			 */
+			siw_init_terminate(qp, TERM_ERROR_LAYER_LLP,
+					   LLP_ETYPE_MPA,
+					   LLP_ECODE_INSUFFICIENT_IRD, 0);
+			siw_send_terminate(qp);
+			rv = -ENOMEM;
+			goto out_err;
+		}
+		if (cep->mpa.v2_ctrl_req.ird & MPA_V2_PEER_TO_PEER)
+			mpa_p2p_mode =
+				cep->mpa.v2_ctrl_req.ord &
+				(MPA_V2_RDMA_WRITE_RTR | MPA_V2_RDMA_READ_RTR);
+
+		/*
+		 * Check if we requested P2P mode, and if peer agrees
+		 */
+		if (mpa_p2p_mode != MPA_V2_RDMA_NO_RTR) {
+			if ((mpa_p2p_mode & v2->ord) == 0) {
+				/*
+				 * We requested RTR mode(s), but the peer
+				 * did not pick any mode we support.
+				 */
+				siw_dbg_cep(cep,
+					    "rtr mode:  req %2x, got %2x\n",
+					    mpa_p2p_mode,
+					    v2->ord & (MPA_V2_RDMA_WRITE_RTR |
+						       MPA_V2_RDMA_READ_RTR));
+
+				siw_init_terminate(qp, TERM_ERROR_LAYER_LLP,
+						   LLP_ETYPE_MPA,
+						   LLP_ECODE_NO_MATCHING_RTR,
+						   0);
+				siw_send_terminate(qp);
+				rv = -EPROTO;
+				goto out_err;
+			}
+			mpa_p2p_mode = v2->ord & (MPA_V2_RDMA_WRITE_RTR |
+						  MPA_V2_RDMA_READ_RTR);
+		}
+	}
+	memset(&qp_attrs, 0, sizeof(qp_attrs));
+
+	if (rep->params.bits & MPA_RR_FLAG_CRC)
+		qp_attrs.flags = SIW_MPA_CRC;
+
+	qp_attrs.irq_size = cep->ird;
+	qp_attrs.orq_size = cep->ord;
+	qp_attrs.sk = cep->sock;
+	qp_attrs.state = SIW_QP_STATE_RTS;
+
+	qp_attr_mask = SIW_QP_ATTR_STATE | SIW_QP_ATTR_LLP_HANDLE |
+		       SIW_QP_ATTR_ORD | SIW_QP_ATTR_IRD | SIW_QP_ATTR_MPA;
+
+	/* Move socket RX/TX under QP control */
+	down_write(&qp->state_lock);
+	if (qp->attrs.state > SIW_QP_STATE_RTR) {
+		rv = -EINVAL;
+		up_write(&qp->state_lock);
+		goto out_err;
+	}
+	rv = siw_qp_modify(qp, &qp_attrs, qp_attr_mask);
+
+	siw_qp_socket_assoc(cep, qp);
+
+	up_write(&qp->state_lock);
+
+	/* Send extra RDMA frame to trigger peer RTS if negotiated */
+	if (mpa_p2p_mode != MPA_V2_RDMA_NO_RTR) {
+		rv = siw_qp_mpa_rts(qp, mpa_p2p_mode);
+		if (rv)
+			goto out_err;
+	}
+	if (!rv) {
+		rv = siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, 0);
+		if (!rv)
+			cep->state = SIW_EPSTATE_RDMA_MODE;
+
+		return 0;
+	}
+
+out_err:
+	siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, -EINVAL);
+
+	return rv;
+}
+
+/*
+ * siw_accept_newconn - accept an incoming pending connection
+ *
+ */
+static void siw_accept_newconn(struct siw_cep *cep)
+{
+	struct socket *s = cep->sock;
+	struct socket *new_s = NULL;
+	struct siw_cep *new_cep = NULL;
+	int rv = 0; /* debug only. should disappear */
+
+	if (cep->state != SIW_EPSTATE_LISTENING)
+		goto error;
+
+	new_cep = siw_cep_alloc(cep->sdev);
+	if (!new_cep)
+		goto error;
+
+	/*
+	 * 4: Allocate a sufficient number of work elements
+	 * to allow concurrent handling of local + peer close
+	 * events, MPA header processing + MPA timeout.
+	 */
+	if (siw_cm_alloc_work(new_cep, 4) != 0)
+		goto error;
+
+	/*
+	 * Copy saved socket callbacks from listening CEP
+	 * and assign new socket with new CEP
+	 */
+	new_cep->sk_state_change = cep->sk_state_change;
+	new_cep->sk_data_ready = cep->sk_data_ready;
+	new_cep->sk_write_space = cep->sk_write_space;
+	new_cep->sk_error_report = cep->sk_error_report;
+
+	rv = kernel_accept(s, &new_s, O_NONBLOCK);
+	if (rv != 0) {
+		/*
+		 * Connection already aborted by peer..?
+		 */
+		siw_dbg_cep(cep, "kernel_accept() error: %d\n", rv);
+		goto error;
+	}
+	new_cep->sock = new_s;
+	siw_cep_get(new_cep);
+	new_s->sk->sk_user_data = new_cep;
+
+	siw_dbg_cep(cep, "listen socket 0x%p, new 0x%p\n", s, new_s);
+
+	if (siw_tcp_nagle == false) {
+		int val = 1;
+
+		rv = kernel_setsockopt(new_s, SOL_TCP, TCP_NODELAY,
+				       (char *)&val, sizeof(val));
+		if (rv) {
+			siw_dbg_cep(cep, "setsockopt NODELAY error: %d\n", rv);
+			goto error;
+		}
+	}
+	new_cep->state = SIW_EPSTATE_AWAIT_MPAREQ;
+
+	rv = siw_cm_queue_work(new_cep, SIW_CM_WORK_MPATIMEOUT);
+	if (rv)
+		goto error;
+	/*
+	 * See siw_proc_mpareq() etc. for the use of new_cep->listen_cep.
+	 */
+	new_cep->listen_cep = cep;
+	siw_cep_get(cep);
+
+	if (atomic_read(&new_s->sk->sk_rmem_alloc)) {
+		/*
+		 * MPA REQ already queued
+		 */
+		siw_dbg_cep(cep, "immediate mpa request\n");
+
+		siw_cep_set_inuse(new_cep);
+		rv = siw_proc_mpareq(new_cep);
+		siw_cep_set_free(new_cep);
+
+		if (rv != -EAGAIN) {
+			siw_cep_put(cep);
+			new_cep->listen_cep = NULL;
+			if (rv)
+				goto error;
+		}
+	}
+	return;
+
+error:
+	if (new_cep)
+		siw_cep_put(new_cep);
+
+	if (new_s) {
+		siw_socket_disassoc(new_s);
+		sock_release(new_s);
+		new_cep->sock = NULL;
+	}
+	siw_dbg_cep(cep, "error %d\n", rv);
+}
+
+static void siw_cm_work_handler(struct work_struct *w)
+{
+	struct siw_cm_work *work;
+	struct siw_cep *cep;
+	int release_cep = 0, rv = 0;
+
+	work = container_of(w, struct siw_cm_work, work.work);
+	cep = work->cep;
+
+	siw_dbg_cep(cep, "[QP %u]: work type: %d, state %d\n",
+		    cep->qp ? qp_id(cep->qp) : -1, work->type, cep->state);
+
+	siw_cep_set_inuse(cep);
+
+	switch (work->type) {
+	case SIW_CM_WORK_ACCEPT:
+		siw_accept_newconn(cep);
+		break;
+
+	case SIW_CM_WORK_READ_MPAHDR:
+		if (cep->state == SIW_EPSTATE_AWAIT_MPAREQ) {
+			if (cep->listen_cep) {
+				siw_cep_set_inuse(cep->listen_cep);
+
+				if (cep->listen_cep->state ==
+				    SIW_EPSTATE_LISTENING)
+					rv = siw_proc_mpareq(cep);
+				else
+					rv = -EFAULT;
+
+				siw_cep_set_free(cep->listen_cep);
+
+				if (rv != -EAGAIN) {
+					siw_cep_put(cep->listen_cep);
+					cep->listen_cep = NULL;
+					if (rv)
+						siw_cep_put(cep);
+				}
+			}
+		} else if (cep->state == SIW_EPSTATE_AWAIT_MPAREP) {
+			rv = siw_proc_mpareply(cep);
+		} else {
+			/*
+			 * CEP already moved out of MPA handshake.
+			 * any connection management already done.
+			 * silently ignore the mpa packet.
+			 */
+			if (cep->state == SIW_EPSTATE_RDMA_MODE) {
+				cep->sock->sk->sk_data_ready(cep->sock->sk);
+				siw_dbg_cep(cep, "already in RDMA mode");
+			} else {
+				siw_dbg_cep(cep, "out of state: %d\n",
+					    cep->state);
+			}
+		}
+		if (rv && rv != EAGAIN)
+			release_cep = 1;
+		break;
+
+	case SIW_CM_WORK_CLOSE_LLP:
+		/*
+		 * QP scheduled LLP close
+		 */
+		if (cep->qp && cep->qp->term_info.valid)
+			siw_send_terminate(cep->qp);
+
+		if (cep->cm_id)
+			siw_cm_upcall(cep, IW_CM_EVENT_CLOSE, 0);
+
+		release_cep = 1;
+		break;
+
+	case SIW_CM_WORK_PEER_CLOSE:
+		if (cep->cm_id) {
+			if (cep->state == SIW_EPSTATE_AWAIT_MPAREP) {
+				/*
+				 * MPA reply not received, but connection drop
+				 */
+				siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY,
+					      -ECONNRESET);
+			} else if (cep->state == SIW_EPSTATE_RDMA_MODE) {
+				/*
+				 * NOTE: IW_CM_EVENT_DISCONNECT is given just
+				 *       to transition IWCM into CLOSING.
+				 */
+				siw_cm_upcall(cep, IW_CM_EVENT_DISCONNECT, 0);
+				siw_cm_upcall(cep, IW_CM_EVENT_CLOSE, 0);
+			}
+			/*
+			 * for other states there is no connection
+			 * known to the IWCM.
+			 */
+		} else {
+			if (cep->state == SIW_EPSTATE_RECVD_MPAREQ) {
+				/*
+				 * Wait for the ulp/CM to call accept/reject
+				 */
+				siw_dbg_cep(cep,
+					    "mpa req recvd, wait for ULP\n");
+			} else if (cep->state == SIW_EPSTATE_AWAIT_MPAREQ) {
+				/*
+				 * Socket close before MPA request received.
+				 */
+				siw_dbg_cep(cep, "no mpareq: drop listener\n");
+				siw_cep_put(cep->listen_cep);
+				cep->listen_cep = NULL;
+			}
+		}
+		release_cep = 1;
+		break;
+
+	case SIW_CM_WORK_MPATIMEOUT:
+		cep->mpa_timer = NULL;
+
+		if (cep->state == SIW_EPSTATE_AWAIT_MPAREP) {
+			/*
+			 * MPA request timed out:
+			 * Hide any partially received private data and signal
+			 * timeout
+			 */
+			cep->mpa.hdr.params.pd_len = 0;
+
+			if (cep->cm_id)
+				siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY,
+					      -ETIMEDOUT);
+			release_cep = 1;
+
+		} else if (cep->state == SIW_EPSTATE_AWAIT_MPAREQ) {
+			/*
+			 * No MPA request received after peer TCP stream setup.
+			 */
+			if (cep->listen_cep) {
+				siw_cep_put(cep->listen_cep);
+				cep->listen_cep = NULL;
+			}
+			release_cep = 1;
+		}
+		break;
+
+	default:
+		WARN(1, "Undefined CM work type: %d\n", work->type);
+	}
+	if (release_cep) {
+		siw_dbg_cep(cep,
+			    "release: timer=%s, QP[%u], id 0x%p\n",
+			    cep->mpa_timer ? "y" : "n",
+			    cep->qp ? qp_id(cep->qp) : -1, cep->cm_id);
+
+		siw_cancel_mpatimer(cep);
+
+		cep->state = SIW_EPSTATE_CLOSED;
+
+		if (cep->qp) {
+			struct siw_qp *qp = cep->qp;
+			/*
+			 * Serialize a potential race with application
+			 * closing the QP and calling siw_qp_cm_drop()
+			 */
+			siw_qp_get(qp);
+			siw_cep_set_free(cep);
+
+			siw_qp_llp_close(qp);
+			siw_qp_put(qp);
+
+			siw_cep_set_inuse(cep);
+			cep->qp = NULL;
+			siw_qp_put(qp);
+		}
+		if (cep->sock) {
+			siw_socket_disassoc(cep->sock);
+			sock_release(cep->sock);
+			cep->sock = NULL;
+		}
+		if (cep->cm_id) {
+			cep->cm_id->rem_ref(cep->cm_id);
+			cep->cm_id = NULL;
+			siw_cep_put(cep);
+		}
+	}
+	siw_cep_set_free(cep);
+	siw_put_work(work);
+	siw_cep_put(cep);
+}
+
+static struct workqueue_struct *siw_cm_wq;
+
+int siw_cm_queue_work(struct siw_cep *cep, enum siw_work_type type)
+{
+	struct siw_cm_work *work = siw_get_work(cep);
+	unsigned long delay = 0;
+
+	if (!work) {
+		siw_dbg_cep(cep, "failed with no work available\n");
+		return -ENOMEM;
+	}
+	work->type = type;
+	work->cep = cep;
+
+	siw_cep_get(cep);
+
+	INIT_DELAYED_WORK(&work->work, siw_cm_work_handler);
+
+	if (type == SIW_CM_WORK_MPATIMEOUT) {
+		cep->mpa_timer = work;
+
+		if (cep->state == SIW_EPSTATE_AWAIT_MPAREP)
+			delay = MPAREQ_TIMEOUT;
+		else
+			delay = MPAREP_TIMEOUT;
+	}
+	siw_dbg_cep(cep, "[QP %u]: work type: %d, work 0x%p, timeout %lu\n",
+		    cep->qp ? qp_id(cep->qp) : -1, type, work, delay);
+
+	queue_delayed_work(siw_cm_wq, &work->work, delay);
+
+	return 0;
+}
+
+static void siw_cm_llp_data_ready(struct sock *sk)
+{
+	struct siw_cep *cep;
+
+	read_lock(&sk->sk_callback_lock);
+
+	cep = sk_to_cep(sk);
+	if (!cep) {
+		WARN_ON(1);
+		goto out;
+	}
+	siw_dbg_cep(cep, "state: %d\n", cep->state);
+
+	switch (cep->state) {
+	case SIW_EPSTATE_RDMA_MODE:
+		/* fall through */
+	case SIW_EPSTATE_LISTENING:
+		break;
+
+	case SIW_EPSTATE_AWAIT_MPAREQ:
+		/* fall through */
+	case SIW_EPSTATE_AWAIT_MPAREP:
+		siw_cm_queue_work(cep, SIW_CM_WORK_READ_MPAHDR);
+		break;
+
+	default:
+		siw_dbg_cep(cep, "unexpected data, state %d\n", cep->state);
+		break;
+	}
+out:
+	read_unlock(&sk->sk_callback_lock);
+}
+
+static void siw_cm_llp_write_space(struct sock *sk)
+{
+	struct siw_cep *cep = sk_to_cep(sk);
+
+	if (cep)
+		siw_dbg_cep(cep, "state: %d\n", cep->state);
+}
+
+static void siw_cm_llp_error_report(struct sock *sk)
+{
+	struct siw_cep *cep = sk_to_cep(sk);
+
+	if (cep) {
+		siw_dbg_cep(cep, "error %d, socket state: %d, cep state: %d\n",
+			    sk->sk_err, sk->sk_state, cep->state);
+		cep->sk_error_report(sk);
+	}
+}
+
+static void siw_cm_llp_state_change(struct sock *sk)
+{
+	struct siw_cep *cep;
+	struct socket *s;
+	void (*orig_state_change)(struct sock *s);
+
+	read_lock(&sk->sk_callback_lock);
+
+	cep = sk_to_cep(sk);
+	if (!cep) {
+		/* endpoint already disassociated */
+		read_unlock(&sk->sk_callback_lock);
+		return;
+	}
+	orig_state_change = cep->sk_state_change;
+
+	s = sk->sk_socket;
+
+	siw_dbg_cep(cep, "state: %d\n", cep->state);
+
+	switch (sk->sk_state) {
+	case TCP_ESTABLISHED:
+		/*
+		 * handle accepting socket as special case where only
+		 * new connection is possible
+		 */
+		siw_cm_queue_work(cep, SIW_CM_WORK_ACCEPT);
+		break;
+
+	case TCP_CLOSE:
+	case TCP_CLOSE_WAIT:
+		if (cep->qp)
+			cep->qp->tx_ctx.tx_suspend = 1;
+		siw_cm_queue_work(cep, SIW_CM_WORK_PEER_CLOSE);
+		break;
+
+	default:
+		siw_dbg_cep(cep, "unexpected socket state %d\n", sk->sk_state);
+	}
+	read_unlock(&sk->sk_callback_lock);
+	orig_state_change(sk);
+}
+
+static int kernel_bindconnect(struct socket *s, struct sockaddr *laddr,
+			      struct sockaddr *raddr)
+{
+	int rv, flags = 0, s_val = 1;
+	size_t size = laddr->sa_family == AF_INET ?
+		sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6);
+
+	/*
+	 * Make address available again asap.
+	 */
+	rv = kernel_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&s_val,
+			       sizeof(s_val));
+	if (rv < 0)
+		return rv;
+
+	rv = s->ops->bind(s, laddr, size);
+	if (rv < 0)
+		return rv;
+
+	rv = s->ops->connect(s, raddr, size, flags);
+
+	return rv < 0 ? rv : 0;
+}
+
+int siw_connect(struct iw_cm_id *id, struct iw_cm_conn_param *params)
+{
+	struct siw_device *sdev = to_siw_dev(id->device);
+	struct siw_qp *qp;
+	struct siw_cep *cep = NULL;
+	struct socket *s = NULL;
+	struct sockaddr *laddr = (struct sockaddr *)&id->local_addr,
+			*raddr = (struct sockaddr *)&id->remote_addr;
+	bool p2p_mode = peer_to_peer, v4 = true;
+	u16 pd_len = params->private_data_len;
+	int version = mpa_version, rv;
+
+	if (pd_len > MPA_MAX_PRIVDATA)
+		return -EINVAL;
+
+	if (params->ird > sdev->attrs.max_ird ||
+	    params->ord > sdev->attrs.max_ord)
+		return -ENOMEM;
+
+	if (laddr->sa_family == AF_INET6)
+		v4 = false;
+	else if (laddr->sa_family != AF_INET)
+		return -EAFNOSUPPORT;
+
+	/*
+	 * Respect any iwarp port mapping: Use mapped remote address
+	 * if valid. Local address must not be mapped, since siw
+	 * uses kernel TCP stack.
+	 */
+	if ((v4 && to_sockaddr_in(id->remote_addr).sin_port != 0) ||
+	     to_sockaddr_in6(id->remote_addr).sin6_port != 0)
+		raddr = (struct sockaddr *)&id->m_remote_addr;
+
+	qp = siw_qp_id2obj(sdev, params->qpn);
+	if (!qp) {
+		WARN(1, "[QP %u] does not exist\n", params->qpn);
+		rv = -EINVAL;
+		goto error;
+	}
+	if (v4)
+		siw_dbg_qp(qp,
+			   "id 0x%p, pd_len %d, laddr %pI4 %d, raddr %pI4 %d\n",
+			   id, pd_len,
+			   &((struct sockaddr_in *)(laddr))->sin_addr,
+			   ntohs(((struct sockaddr_in *)(laddr))->sin_port),
+			   &((struct sockaddr_in *)(raddr))->sin_addr,
+			   ntohs(((struct sockaddr_in *)(raddr))->sin_port));
+	else
+		siw_dbg_qp(qp,
+			   "id 0x%p, pd_len %d, laddr %pI6 %d, raddr %pI6 %d\n",
+			   id, pd_len,
+			   &((struct sockaddr_in6 *)(laddr))->sin6_addr,
+			   ntohs(((struct sockaddr_in6 *)(laddr))->sin6_port),
+			   &((struct sockaddr_in6 *)(raddr))->sin6_addr,
+			   ntohs(((struct sockaddr_in6 *)(raddr))->sin6_port));
+
+	rv = sock_create(v4 ? AF_INET : AF_INET6, SOCK_STREAM, IPPROTO_TCP, &s);
+	if (rv < 0)
+		goto error;
+
+	/*
+	 * NOTE: For simplification, connect() is called in blocking
+	 * mode. Might be reconsidered for async connection setup at
+	 * TCP level.
+	 */
+	rv = kernel_bindconnect(s, laddr, raddr);
+	if (rv != 0) {
+		siw_dbg_qp(qp, "kernel_bindconnect: error %d\n", rv);
+		goto error;
+	}
+	if (siw_tcp_nagle == false) {
+		int val = 1;
+
+		rv = kernel_setsockopt(s, SOL_TCP, TCP_NODELAY, (char *)&val,
+				       sizeof(val));
+		if (rv) {
+			siw_dbg_qp(qp, "setsockopt NODELAY error: %d\n", rv);
+			goto error;
+		}
+	}
+	cep = siw_cep_alloc(sdev);
+	if (!cep) {
+		rv = -ENOMEM;
+		goto error;
+	}
+	siw_cep_set_inuse(cep);
+
+	/* Associate QP with CEP */
+	siw_cep_get(cep);
+	qp->cep = cep;
+
+	/* siw_qp_get(qp) already done by QP lookup */
+	cep->qp = qp;
+
+	id->add_ref(id);
+	cep->cm_id = id;
+
+	/*
+	 * 4: Allocate a sufficient number of work elements
+	 * to allow concurrent handling of local + peer close
+	 * events, MPA header processing + MPA timeout.
+	 */
+	rv = siw_cm_alloc_work(cep, 4);
+	if (rv != 0) {
+		rv = -ENOMEM;
+		goto error;
+	}
+	cep->ird = params->ird;
+	cep->ord = params->ord;
+
+	if (p2p_mode && cep->ord == 0)
+		cep->ord = 1;
+
+	cep->state = SIW_EPSTATE_CONNECTING;
+
+	/*
+	 * Associate CEP with socket
+	 */
+	siw_cep_socket_assoc(cep, s);
+
+	cep->state = SIW_EPSTATE_AWAIT_MPAREP;
+
+	/*
+	 * Set MPA Request bits: CRC if required, no MPA Markers,
+	 * MPA Rev. according to module parameter 'mpa_version', Key 'Request'.
+	 */
+	cep->mpa.hdr.params.bits = 0;
+	if (version > MPA_REVISION_2) {
+		pr_warn("Setting MPA version to %u\n", MPA_REVISION_2);
+		version = MPA_REVISION_2;
+		/* Adjust also module parameter */
+		mpa_version = MPA_REVISION_2;
+	}
+	__mpa_rr_set_revision(&cep->mpa.hdr.params.bits, version);
+
+	if (try_gso)
+		cep->mpa.hdr.params.bits |= MPA_RR_FLAG_GSO_EXP;
+
+	if (mpa_crc_required)
+		cep->mpa.hdr.params.bits |= MPA_RR_FLAG_CRC;
+
+	/*
+	 * If MPA version == 2:
+	 * o Include ORD and IRD.
+	 * o Indicate peer-to-peer mode, if required by module
+	 *   parameter 'peer_to_peer'.
+	 */
+	if (version == MPA_REVISION_2) {
+		cep->enhanced_rdma_conn_est = true;
+		cep->mpa.hdr.params.bits |= MPA_RR_FLAG_ENHANCED;
+
+		cep->mpa.v2_ctrl.ird = htons(cep->ird);
+		cep->mpa.v2_ctrl.ord = htons(cep->ord);
+
+		if (p2p_mode) {
+			cep->mpa.v2_ctrl.ird |= MPA_V2_PEER_TO_PEER;
+			cep->mpa.v2_ctrl.ord |= rtr_type;
+		}
+		/* Remember own P2P mode requested */
+		cep->mpa.v2_ctrl_req.ird = cep->mpa.v2_ctrl.ird;
+		cep->mpa.v2_ctrl_req.ord = cep->mpa.v2_ctrl.ord;
+	}
+	memcpy(cep->mpa.hdr.key, MPA_KEY_REQ, 16);
+
+	rv = siw_send_mpareqrep(cep, params->private_data, pd_len);
+	/*
+	 * Reset private data.
+	 */
+	cep->mpa.hdr.params.pd_len = 0;
+
+	if (rv >= 0) {
+		rv = siw_cm_queue_work(cep, SIW_CM_WORK_MPATIMEOUT);
+		if (!rv) {
+			siw_dbg_cep(cep, "id 0x%p, [QP %u]: exit\n", id,
+				    qp_id(qp));
+			siw_cep_set_free(cep);
+			return 0;
+		}
+	}
+error:
+	siw_dbg_qp(qp, "failed: %d\n", rv);
+
+	if (cep) {
+		siw_socket_disassoc(s);
+		sock_release(s);
+		cep->sock = NULL;
+
+		cep->qp = NULL;
+
+		cep->cm_id = NULL;
+		id->rem_ref(id);
+		siw_cep_put(cep);
+
+		qp->cep = NULL;
+		siw_cep_put(cep);
+
+		cep->state = SIW_EPSTATE_CLOSED;
+
+		siw_cep_set_free(cep);
+
+		siw_cep_put(cep);
+
+	} else if (s) {
+		sock_release(s);
+	}
+	siw_qp_put(qp);
+
+	return rv;
+}
+
+/*
+ * siw_accept - Let SoftiWARP accept an RDMA connection request
+ *
+ * @id:		New connection management id to be used for accepted
+ *		connection request
+ * @params:	Connection parameters provided by ULP for accepting connection
+ *
+ * Transition QP to RTS state, associate new CM id @id with accepted CEP
+ * and get prepared for TCP input by installing socket callbacks.
+ * Then send MPA Reply and generate the "connection established" event.
+ * Socket callbacks must be installed before sending MPA Reply, because
+ * the latter may cause a first RDMA message to arrive from the RDMA Initiator
+ * side very quickly, at which time the socket callbacks must be ready.
+ */
+int siw_accept(struct iw_cm_id *id, struct iw_cm_conn_param *params)
+{
+	struct siw_device *sdev = to_siw_dev(id->device);
+	struct siw_cep *cep = (struct siw_cep *)id->provider_data;
+	struct siw_qp *qp;
+	struct siw_qp_attrs qp_attrs;
+	int rv, max_priv_data = MPA_MAX_PRIVDATA;
+	bool wait_for_peer_rts = false;
+
+	siw_cep_set_inuse(cep);
+	siw_cep_put(cep);
+
+	/* Free lingering inbound private data */
+	if (cep->mpa.hdr.params.pd_len) {
+		cep->mpa.hdr.params.pd_len = 0;
+		kfree(cep->mpa.pdata);
+		cep->mpa.pdata = NULL;
+	}
+	siw_cancel_mpatimer(cep);
+
+	if (cep->state != SIW_EPSTATE_RECVD_MPAREQ) {
+		siw_dbg_cep(cep, "id 0x%p: out of state\n", id);
+
+		siw_cep_set_free(cep);
+		siw_cep_put(cep);
+
+		return -ECONNRESET;
+	}
+	qp = siw_qp_id2obj(sdev, params->qpn);
+	if (!qp) {
+		WARN(1, "[QP %d] does not exist\n", params->qpn);
+		siw_cep_set_free(cep);
+		siw_cep_put(cep);
+
+		return -EINVAL;
+	}
+	down_write(&qp->state_lock);
+	if (qp->attrs.state > SIW_QP_STATE_RTR) {
+		rv = -EINVAL;
+		up_write(&qp->state_lock);
+		goto error;
+	}
+	siw_dbg_cep(cep, "id 0x%p\n", id);
+
+	if (try_gso && cep->mpa.hdr.params.bits & MPA_RR_FLAG_GSO_EXP) {
+		siw_dbg_cep(cep, "peer allows GSO on TX\n");
+		qp->tx_ctx.gso_seg_limit = 0;
+	}
+	if (params->ord > sdev->attrs.max_ord ||
+	    params->ird > sdev->attrs.max_ird) {
+		siw_dbg_cep(
+			cep,
+			"id 0x%p, [QP %u]: ord %d (max %d), ird %d (max %d)\n",
+			id, qp_id(qp), params->ord, sdev->attrs.max_ord,
+			params->ird, sdev->attrs.max_ird);
+		rv = -EINVAL;
+		up_write(&qp->state_lock);
+		goto error;
+	}
+	if (cep->enhanced_rdma_conn_est)
+		max_priv_data -= sizeof(struct mpa_v2_data);
+
+	if (params->private_data_len > max_priv_data) {
+		siw_dbg_cep(
+			cep,
+			"id 0x%p, [QP %u]: private data length: %d (max %d)\n",
+			id, qp_id(qp), params->private_data_len, max_priv_data);
+		rv = -EINVAL;
+		up_write(&qp->state_lock);
+		goto error;
+	}
+	if (cep->enhanced_rdma_conn_est) {
+		if (params->ord > cep->ord) {
+			if (relaxed_ird_negotiation) {
+				params->ord = cep->ord;
+			} else {
+				cep->ird = params->ird;
+				cep->ord = params->ord;
+				rv = -EINVAL;
+				up_write(&qp->state_lock);
+				goto error;
+			}
+		}
+		if (params->ird < cep->ird) {
+			if (relaxed_ird_negotiation &&
+			    cep->ird <= sdev->attrs.max_ird)
+				params->ird = cep->ird;
+			else {
+				rv = -ENOMEM;
+				up_write(&qp->state_lock);
+				goto error;
+			}
+		}
+		if (cep->mpa.v2_ctrl.ord &
+		    (MPA_V2_RDMA_WRITE_RTR | MPA_V2_RDMA_READ_RTR))
+			wait_for_peer_rts = true;
+		/*
+		 * Signal back negotiated IRD and ORD values
+		 */
+		cep->mpa.v2_ctrl.ord =
+			htons(params->ord & MPA_IRD_ORD_MASK) |
+			(cep->mpa.v2_ctrl.ord & ~MPA_V2_MASK_IRD_ORD);
+		cep->mpa.v2_ctrl.ird =
+			htons(params->ird & MPA_IRD_ORD_MASK) |
+			(cep->mpa.v2_ctrl.ird & ~MPA_V2_MASK_IRD_ORD);
+	}
+	cep->ird = params->ird;
+	cep->ord = params->ord;
+
+	cep->cm_id = id;
+	id->add_ref(id);
+
+	memset(&qp_attrs, 0, sizeof(qp_attrs));
+	qp_attrs.orq_size = cep->ord;
+	qp_attrs.irq_size = cep->ird;
+	qp_attrs.sk = cep->sock;
+	if (cep->mpa.hdr.params.bits & MPA_RR_FLAG_CRC)
+		qp_attrs.flags = SIW_MPA_CRC;
+	qp_attrs.state = SIW_QP_STATE_RTS;
+
+	siw_dbg_cep(cep, "id 0x%p, [QP%u]: moving to rts\n", id, qp_id(qp));
+
+	/* Associate QP with CEP */
+	siw_cep_get(cep);
+	qp->cep = cep;
+
+	/* siw_qp_get(qp) already done by QP lookup */
+	cep->qp = qp;
+
+	cep->state = SIW_EPSTATE_RDMA_MODE;
+
+	/* Move socket RX/TX under QP control */
+	rv = siw_qp_modify(qp, &qp_attrs,
+			   SIW_QP_ATTR_STATE | SIW_QP_ATTR_LLP_HANDLE |
+				   SIW_QP_ATTR_ORD | SIW_QP_ATTR_IRD |
+				   SIW_QP_ATTR_MPA);
+	up_write(&qp->state_lock);
+
+	if (rv)
+		goto error;
+
+	siw_dbg_cep(cep, "id 0x%p, [QP %u]: send mpa reply, %d byte pdata\n",
+		    id, qp_id(qp), params->private_data_len);
+
+	rv = siw_send_mpareqrep(cep, params->private_data,
+				params->private_data_len);
+	if (rv != 0)
+		goto error;
+
+	if (wait_for_peer_rts) {
+		siw_sk_assign_rtr_upcalls(cep);
+	} else {
+		siw_qp_socket_assoc(cep, qp);
+		rv = siw_cm_upcall(cep, IW_CM_EVENT_ESTABLISHED, 0);
+		if (rv)
+			goto error;
+	}
+	siw_cep_set_free(cep);
+
+	return 0;
+error:
+	siw_socket_disassoc(cep->sock);
+	sock_release(cep->sock);
+	cep->sock = NULL;
+
+	cep->state = SIW_EPSTATE_CLOSED;
+
+	if (cep->cm_id) {
+		cep->cm_id->rem_ref(id);
+		cep->cm_id = NULL;
+	}
+	if (qp->cep) {
+		siw_cep_put(cep);
+		qp->cep = NULL;
+	}
+	cep->qp = NULL;
+	siw_qp_put(qp);
+
+	siw_cep_set_free(cep);
+	siw_cep_put(cep);
+
+	return rv;
+}
+
+/*
+ * siw_reject()
+ *
+ * Local connection reject case. Send private data back to peer,
+ * close connection and dereference connection id.
+ */
+int siw_reject(struct iw_cm_id *id, const void *pdata, u8 pd_len)
+{
+	struct siw_cep *cep = (struct siw_cep *)id->provider_data;
+
+	siw_cep_set_inuse(cep);
+	siw_cep_put(cep);
+
+	siw_cancel_mpatimer(cep);
+
+	if (cep->state != SIW_EPSTATE_RECVD_MPAREQ) {
+		siw_dbg_cep(cep, "id 0x%p: out of state\n", id);
+
+		siw_cep_set_free(cep);
+		siw_cep_put(cep); /* put last reference */
+
+		return -ECONNRESET;
+	}
+	siw_dbg_cep(cep, "id 0x%p, cep->state %d, pd_len %d\n", id, cep->state,
+		    pd_len);
+
+	if (__mpa_rr_revision(cep->mpa.hdr.params.bits) >= MPA_REVISION_1) {
+		cep->mpa.hdr.params.bits |= MPA_RR_FLAG_REJECT; /* reject */
+		siw_send_mpareqrep(cep, pdata, pd_len);
+	}
+	siw_socket_disassoc(cep->sock);
+	sock_release(cep->sock);
+	cep->sock = NULL;
+
+	cep->state = SIW_EPSTATE_CLOSED;
+
+	siw_cep_set_free(cep);
+	siw_cep_put(cep);
+
+	return 0;
+}
+
+static int siw_listen_address(struct iw_cm_id *id, int backlog,
+			      struct sockaddr *laddr, int addr_family)
+{
+	struct socket *s;
+	struct siw_cep *cep = NULL;
+	struct siw_device *sdev = to_siw_dev(id->device);
+	int rv = 0, s_val;
+
+	rv = sock_create(addr_family, SOCK_STREAM, IPPROTO_TCP, &s);
+	if (rv < 0)
+		return rv;
+
+	/*
+	 * Allow binding local port when still in TIME_WAIT from last close.
+	 */
+	s_val = 1;
+	rv = kernel_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&s_val,
+			       sizeof(s_val));
+	if (rv) {
+		siw_dbg(id->device, "id 0x%p: setsockopt error: %d\n", id, rv);
+		goto error;
+	}
+	rv = s->ops->bind(s, laddr, addr_family == AF_INET ?
+				    sizeof(struct sockaddr_in) :
+				    sizeof(struct sockaddr_in6));
+	if (rv) {
+		siw_dbg(id->device, "id 0x%p: socket bind error: %d\n", id, rv);
+		goto error;
+	}
+	cep = siw_cep_alloc(sdev);
+	if (!cep) {
+		rv = -ENOMEM;
+		goto error;
+	}
+	siw_cep_socket_assoc(cep, s);
+
+	rv = siw_cm_alloc_work(cep, backlog);
+	if (rv) {
+		siw_dbg(id->device,
+			"id 0x%p: alloc_work error %d, backlog %d\n", id,
+			rv, backlog);
+		goto error;
+	}
+	rv = s->ops->listen(s, backlog);
+	if (rv) {
+		siw_dbg(id->device, "id 0x%p: listen error %d\n", id, rv);
+		goto error;
+	}
+	cep->cm_id = id;
+	id->add_ref(id);
+
+	/*
+	 * In case of a wildcard rdma_listen on a multi-homed device,
+	 * a listener's IWCM id is associated with more than one listening CEP.
+	 *
+	 * We currently use id->provider_data in three different ways:
+	 *
+	 * o For a listener's IWCM id, id->provider_data points to
+	 *   the list_head of the list of listening CEPs.
+	 *   Uses: siw_create_listen(), siw_destroy_listen()
+	 *
+	 * o For each accepted passive-side IWCM id, id->provider_data
+	 *   points to the CEP itself. This is a consequence of
+	 *   - siw_cm_upcall() setting event.provider_data = cep and
+	 *   - the IWCM's cm_conn_req_handler() setting provider_data of the
+	 *     new passive-side IWCM id equal to event.provider_data
+	 *   Uses: siw_accept(), siw_reject()
+	 *
+	 * o For an active-side IWCM id, id->provider_data is not used at all.
+	 *
+	 */
+	if (!id->provider_data) {
+		id->provider_data =
+			kmalloc(sizeof(struct list_head), GFP_KERNEL);
+		if (!id->provider_data) {
+			rv = -ENOMEM;
+			goto error;
+		}
+		INIT_LIST_HEAD((struct list_head *)id->provider_data);
+	}
+	list_add_tail(&cep->listenq, (struct list_head *)id->provider_data);
+	cep->state = SIW_EPSTATE_LISTENING;
+
+	if (addr_family == AF_INET)
+		siw_dbg(id->device, "Listen at laddr %pI4 %u\n",
+			&(((struct sockaddr_in *)laddr)->sin_addr),
+			((struct sockaddr_in *)laddr)->sin_port);
+	else
+		siw_dbg(id->device, "Listen at laddr %pI6 %u\n",
+			&(((struct sockaddr_in6 *)laddr)->sin6_addr),
+			((struct sockaddr_in6 *)laddr)->sin6_port);
+
+	return 0;
+
+error:
+	siw_dbg(id->device, "failed: %d\n", rv);
+
+	if (cep) {
+		siw_cep_set_inuse(cep);
+
+		if (cep->cm_id) {
+			cep->cm_id->rem_ref(cep->cm_id);
+			cep->cm_id = NULL;
+		}
+		cep->sock = NULL;
+		siw_socket_disassoc(s);
+		cep->state = SIW_EPSTATE_CLOSED;
+
+		siw_cep_set_free(cep);
+		siw_cep_put(cep);
+	}
+	sock_release(s);
+
+	return rv;
+}
+
+static void siw_drop_listeners(struct iw_cm_id *id)
+{
+	struct list_head *p, *tmp;
+
+	/*
+	 * In case of a wildcard rdma_listen on a multi-homed device,
+	 * a listener's IWCM id is associated with more than one listening CEP.
+	 */
+	list_for_each_safe(p, tmp, (struct list_head *)id->provider_data) {
+		struct siw_cep *cep = list_entry(p, struct siw_cep, listenq);
+
+		list_del(p);
+
+		siw_dbg_cep(cep, "id 0x%p: drop cep, state %d\n", id,
+			    cep->state);
+
+		siw_cep_set_inuse(cep);
+
+		if (cep->cm_id) {
+			cep->cm_id->rem_ref(cep->cm_id);
+			cep->cm_id = NULL;
+		}
+		if (cep->sock) {
+			siw_socket_disassoc(cep->sock);
+			sock_release(cep->sock);
+			cep->sock = NULL;
+		}
+		cep->state = SIW_EPSTATE_CLOSED;
+		siw_cep_set_free(cep);
+		siw_cep_put(cep);
+	}
+}
+
+/*
+ * siw_create_listen - Create resources for a listener's IWCM ID @id
+ *
+ * Listens on the socket addresses id->local_addr and id->remote_addr.
+ *
+ * If the listener's @id provides a specific local IP address, at most one
+ * listening socket is created and associated with @id.
+ *
+ * If the listener's @id provides the wildcard (zero) local IP address,
+ * a separate listen is performed for each local IP address of the device
+ * by creating a listening socket and binding to that local IP address.
+ *
+ */
+int siw_create_listen(struct iw_cm_id *id, int backlog)
+{
+	struct net_device *dev = to_siw_dev(id->device)->netdev;
+	int rv = 0, listeners = 0;
+
+	siw_dbg(id->device, "id 0x%p: backlog %d\n", id, backlog);
+
+	/*
+	 * For each attached address of the interface, create a
+	 * listening socket, if id->local_addr is the wildcard
+	 * IP address or matches the IP address.
+	 */
+	if (id->local_addr.ss_family == AF_INET) {
+		struct in_device *in_dev = in_dev_get(dev);
+		struct sockaddr_in s_laddr, *s_raddr;
+
+		memcpy(&s_laddr, &id->local_addr, sizeof(s_laddr));
+		s_raddr = (struct sockaddr_in *)&id->remote_addr;
+
+		siw_dbg(id->device,
+			"id 0x%p: laddr %pI4:%d, raddr %pI4:%d\n",
+			id, &s_laddr.sin_addr, ntohs(s_laddr.sin_port),
+			&s_raddr->sin_addr, ntohs(s_raddr->sin_port));
+
+		for_ifa(in_dev)
+		{
+			if (ipv4_is_zeronet(s_laddr.sin_addr.s_addr) ||
+			    s_laddr.sin_addr.s_addr == ifa->ifa_address) {
+				s_laddr.sin_addr.s_addr = ifa->ifa_address;
+
+				rv = siw_listen_address(id, backlog,
+						(struct sockaddr *)&s_laddr,
+						AF_INET);
+				if (!rv)
+					listeners++;
+			}
+		}
+		endfor_ifa(in_dev);
+		in_dev_put(in_dev);
+	} else if (id->local_addr.ss_family == AF_INET6) {
+		struct inet6_dev *in6_dev = in6_dev_get(dev);
+		struct inet6_ifaddr *ifp;
+		struct sockaddr_in6 *s_laddr = &to_sockaddr_in6(id->local_addr),
+			*s_raddr = &to_sockaddr_in6(id->remote_addr);
+
+		siw_dbg(id->device,
+			"id 0x%p: laddr %pI6:%d, raddr %pI6:%d\n",
+			id, &s_laddr->sin6_addr, ntohs(s_laddr->sin6_port),
+			&s_raddr->sin6_addr, ntohs(s_raddr->sin6_port));
+
+		read_lock_bh(&in6_dev->lock);
+		list_for_each_entry(ifp, &in6_dev->addr_list, if_list) {
+			struct sockaddr_in6 bind_addr;
+
+			if (ipv6_addr_any(&s_laddr->sin6_addr) ||
+			    ipv6_addr_equal(&s_laddr->sin6_addr, &ifp->addr)) {
+				bind_addr.sin6_family = AF_INET6;
+				bind_addr.sin6_port = s_laddr->sin6_port;
+				bind_addr.sin6_flowinfo = 0;
+				bind_addr.sin6_addr = ifp->addr;
+				bind_addr.sin6_scope_id = dev->ifindex;
+
+				rv = siw_listen_address(id, backlog,
+						(struct sockaddr *)&bind_addr,
+						AF_INET6);
+				if (!rv)
+					listeners++;
+			}
+		}
+		read_unlock_bh(&in6_dev->lock);
+
+		in6_dev_put(in6_dev);
+	} else {
+		return -EAFNOSUPPORT;
+	}
+	if (listeners)
+		rv = 0;
+	else if (!rv)
+		rv = -EINVAL;
+
+	siw_dbg(id->device, "id 0x%p: %s\n", id, rv ? "FAIL" : "OK");
+
+	return rv;
+}
+
+int siw_destroy_listen(struct iw_cm_id *id)
+{
+	siw_dbg(id->device, "id 0x%p\n", id);
+
+	if (!id->provider_data) {
+		siw_dbg(id->device, "id 0x%p: no cep(s)\n", id);
+		return 0;
+	}
+	siw_drop_listeners(id);
+	kfree(id->provider_data);
+	id->provider_data = NULL;
+
+	return 0;
+}
+
+int siw_cm_init(void)
+{
+	/*
+	 * create_single_workqueue for strict ordering
+	 */
+	siw_cm_wq = create_singlethread_workqueue("siw_cm_wq");
+	if (!siw_cm_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void siw_cm_exit(void)
+{
+	if (siw_cm_wq) {
+		flush_workqueue(siw_cm_wq);
+		destroy_workqueue(siw_cm_wq);
+	}
+}

drivers/infiniband/sw/siw/siw_cm.h

+/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
+
+/* Authors: Bernard Metzler <bmt@zurich.ibm.com> */
+/*          Greg Joyce <greg@opengridcomputing.com> */
+/* Copyright (c) 2008-2019, IBM Corporation */
+/* Copyright (c) 2017, Open Grid Computing, Inc. */
+
+#ifndef _SIW_CM_H
+#define _SIW_CM_H
+
+#include <net/sock.h>
+#include <linux/tcp.h>
+
+#include <rdma/iw_cm.h>
+
+enum siw_cep_state {
+	SIW_EPSTATE_IDLE = 1,
+	SIW_EPSTATE_LISTENING,
+	SIW_EPSTATE_CONNECTING,
+	SIW_EPSTATE_AWAIT_MPAREQ,
+	SIW_EPSTATE_RECVD_MPAREQ,
+	SIW_EPSTATE_AWAIT_MPAREP,
+	SIW_EPSTATE_RDMA_MODE,
+	SIW_EPSTATE_CLOSED
+};
+
+struct siw_mpa_info {
+	struct mpa_rr hdr; /* peer mpa hdr in host byte order */
+	struct mpa_v2_data v2_ctrl;
+	struct mpa_v2_data v2_ctrl_req;
+	char *pdata;
+	int bytes_rcvd;
+};
+
+struct siw_device;
+
+struct siw_cep {
+	struct iw_cm_id *cm_id;
+	struct siw_device *sdev;
+	struct list_head devq;
+	spinlock_t lock;
+	struct kref ref;
+	int in_use;
+	wait_queue_head_t waitq;
+	enum siw_cep_state state;
+
+	struct list_head listenq;
+	struct siw_cep *listen_cep;
+
+	struct siw_qp *qp;
+	struct socket *sock;
+
+	struct siw_cm_work *mpa_timer;
+	struct list_head work_freelist;
+
+	struct siw_mpa_info mpa;
+	int ord;
+	int ird;
+	bool enhanced_rdma_conn_est;
+
+	/* Saved upcalls of socket */
+	void (*sk_state_change)(struct sock *sk);
+	void (*sk_data_ready)(struct sock *sk);
+	void (*sk_write_space)(struct sock *sk);
+	void (*sk_error_report)(struct sock *sk);
+};
+
+/*
+ * Connection initiator waits 10 seconds to receive an
+ * MPA reply after sending out MPA request. Reponder waits for
+ * 5 seconds for MPA request to arrive if new TCP connection
+ * was set up.
+ */
+#define MPAREQ_TIMEOUT (HZ * 10)
+#define MPAREP_TIMEOUT (HZ * 5)
+
+enum siw_work_type {
+	SIW_CM_WORK_ACCEPT = 1,
+	SIW_CM_WORK_READ_MPAHDR,
+	SIW_CM_WORK_CLOSE_LLP, /* close socket */
+	SIW_CM_WORK_PEER_CLOSE, /* socket indicated peer close */
+	SIW_CM_WORK_MPATIMEOUT
+};
+
+struct siw_cm_work {
+	struct delayed_work work;
+	struct list_head list;
+	enum siw_work_type type;
+	struct siw_cep *cep;
+};
+
+#define to_sockaddr_in(a) (*(struct sockaddr_in *)(&(a)))
+#define to_sockaddr_in6(a) (*(struct sockaddr_in6 *)(&(a)))
+
+static inline int getname_peer(struct socket *s, struct sockaddr_storage *a)
+{
+	return s->ops->getname(s, (struct sockaddr *)a, 1);
+}
+
+static inline int getname_local(struct socket *s, struct sockaddr_storage *a)
+{
+	return s->ops->getname(s, (struct sockaddr *)a, 0);
+}
+
+static inline int ksock_recv(struct socket *sock, char *buf, size_t size,
+			     int flags)
+{
+	struct kvec iov = { buf, size };
+	struct msghdr msg = { .msg_name = NULL, .msg_flags = flags };
+
+	return kernel_recvmsg(sock, &msg, &iov, 1, size, flags);
+}
+
+int siw_connect(struct iw_cm_id *id, struct iw_cm_conn_param *parm);
+int siw_accept(struct iw_cm_id *id, struct iw_cm_conn_param *param);
+int siw_reject(struct iw_cm_id *id, const void *data, u8 len);
+int siw_create_listen(struct iw_cm_id *id, int backlog);
+int siw_destroy_listen(struct iw_cm_id *id);
+
+void siw_cep_get(struct siw_cep *cep);
+void siw_cep_put(struct siw_cep *cep);
+int siw_cm_queue_work(struct siw_cep *cep, enum siw_work_type type);
+
+int siw_cm_init(void);
+void siw_cm_exit(void);
+
+/*
+ * TCP socket interface
+ */
+#define sk_to_qp(sk) (((struct siw_cep *)((sk)->sk_user_data))->qp)
+#define sk_to_cep(sk) ((struct siw_cep *)((sk)->sk_user_data))
+
+#endif