Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3563 insertions, 0 deletions

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
new file mode 100644
index 000000000..b6609527d
--- /dev/null
+++ b/net/smc/af_smc.c
@@ -0,0 +1,3563 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  AF_SMC protocol family socket handler keeping the AF_INET sock address type
+ *  applies to SOCK_STREAM sockets only
+ *  offers an alternative communication option for TCP-protocol sockets
+ *  applicable with RoCE-cards only
+ *
+ *  Initial restrictions:
+ *    - support for alternate links postponed
+ *
+ *  Copyright IBM Corp. 2016, 2018
+ *
+ *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
+ *              based on prototype from Frank Blaschka
+ */
+
+#define KMSG_COMPONENT "smc"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/socket.h>
+#include <linux/workqueue.h>
+#include <linux/in.h>
+#include <linux/sched/signal.h>
+#include <linux/if_vlan.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/ctype.h>
+
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/smc.h>
+#include <asm/ioctls.h>
+
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include "smc_netns.h"
+
+#include "smc.h"
+#include "smc_clc.h"
+#include "smc_llc.h"
+#include "smc_cdc.h"
+#include "smc_core.h"
+#include "smc_ib.h"
+#include "smc_ism.h"
+#include "smc_pnet.h"
+#include "smc_netlink.h"
+#include "smc_tx.h"
+#include "smc_rx.h"
+#include "smc_close.h"
+#include "smc_stats.h"
+#include "smc_tracepoint.h"
+#include "smc_sysctl.h"
+
+static DEFINE_MUTEX(smc_server_lgr_pending);	/* serialize link group
+						 * creation on server
+						 */
+static DEFINE_MUTEX(smc_client_lgr_pending);	/* serialize link group
+						 * creation on client
+						 */
+
+static struct workqueue_struct	*smc_tcp_ls_wq;	/* wq for tcp listen work */
+struct workqueue_struct	*smc_hs_wq;	/* wq for handshake work */
+struct workqueue_struct	*smc_close_wq;	/* wq for close work */
+
+static void smc_tcp_listen_work(struct work_struct *);
+static void smc_connect_work(struct work_struct *);
+
+int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	void *hdr;
+
+	if (cb_ctx->pos[0])
+		goto out;
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &smc_gen_nl_family, NLM_F_MULTI,
+			  SMC_NETLINK_DUMP_HS_LIMITATION);
+	if (!hdr)
+		return -ENOMEM;
+
+	if (nla_put_u8(skb, SMC_NLA_HS_LIMITATION_ENABLED,
+		       sock_net(skb->sk)->smc.limit_smc_hs))
+		goto err;
+
+	genlmsg_end(skb, hdr);
+	cb_ctx->pos[0] = 1;
+out:
+	return skb->len;
+err:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+int smc_nl_enable_hs_limitation(struct sk_buff *skb, struct genl_info *info)
+{
+	sock_net(skb->sk)->smc.limit_smc_hs = true;
+	return 0;
+}
+
+int smc_nl_disable_hs_limitation(struct sk_buff *skb, struct genl_info *info)
+{
+	sock_net(skb->sk)->smc.limit_smc_hs = false;
+	return 0;
+}
+
+static void smc_set_keepalive(struct sock *sk, int val)
+{
+	struct smc_sock *smc = smc_sk(sk);
+
+	smc->clcsock->sk->sk_prot->keepalive(smc->clcsock->sk, val);
+}
+
+static struct sock *smc_tcp_syn_recv_sock(const struct sock *sk,
+					  struct sk_buff *skb,
+					  struct request_sock *req,
+					  struct dst_entry *dst,
+					  struct request_sock *req_unhash,
+					  bool *own_req)
+{
+	struct smc_sock *smc;
+	struct sock *child;
+
+	smc = smc_clcsock_user_data(sk);
+
+	if (READ_ONCE(sk->sk_ack_backlog) + atomic_read(&smc->queued_smc_hs) >
+				sk->sk_max_ack_backlog)
+		goto drop;
+
+	if (sk_acceptq_is_full(&smc->sk)) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+		goto drop;
+	}
+
+	/* passthrough to original syn recv sock fct */
+	child = smc->ori_af_ops->syn_recv_sock(sk, skb, req, dst, req_unhash,
+					       own_req);
+	/* child must not inherit smc or its ops */
+	if (child) {
+		rcu_assign_sk_user_data(child, NULL);
+
+		/* v4-mapped sockets don't inherit parent ops. Don't restore. */
+		if (inet_csk(child)->icsk_af_ops == inet_csk(sk)->icsk_af_ops)
+			inet_csk(child)->icsk_af_ops = smc->ori_af_ops;
+	}
+	return child;
+
+drop:
+	dst_release(dst);
+	tcp_listendrop(sk);
+	return NULL;
+}
+
+static bool smc_hs_congested(const struct sock *sk)
+{
+	const struct smc_sock *smc;
+
+	smc = smc_clcsock_user_data(sk);
+
+	if (!smc)
+		return true;
+
+	if (workqueue_congested(WORK_CPU_UNBOUND, smc_hs_wq))
+		return true;
+
+	return false;
+}
+
+static struct smc_hashinfo smc_v4_hashinfo = {
+	.lock = __RW_LOCK_UNLOCKED(smc_v4_hashinfo.lock),
+};
+
+static struct smc_hashinfo smc_v6_hashinfo = {
+	.lock = __RW_LOCK_UNLOCKED(smc_v6_hashinfo.lock),
+};
+
+int smc_hash_sk(struct sock *sk)
+{
+	struct smc_hashinfo *h = sk->sk_prot->h.smc_hash;
+	struct hlist_head *head;
+
+	head = &h->ht;
+
+	write_lock_bh(&h->lock);
+	sk_add_node(sk, head);
+	write_unlock_bh(&h->lock);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(smc_hash_sk);
+
+void smc_unhash_sk(struct sock *sk)
+{
+	struct smc_hashinfo *h = sk->sk_prot->h.smc_hash;
+
+	write_lock_bh(&h->lock);
+	if (sk_del_node_init(sk))
+		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+	write_unlock_bh(&h->lock);
+}
+EXPORT_SYMBOL_GPL(smc_unhash_sk);
+
+/* This will be called before user really release sock_lock. So do the
+ * work which we didn't do because of user hold the sock_lock in the
+ * BH context
+ */
+static void smc_release_cb(struct sock *sk)
+{
+	struct smc_sock *smc = smc_sk(sk);
+
+	if (smc->conn.tx_in_release_sock) {
+		smc_tx_pending(&smc->conn);
+		smc->conn.tx_in_release_sock = false;
+	}
+}
+
+struct proto smc_proto = {
+	.name		= "SMC",
+	.owner		= THIS_MODULE,
+	.keepalive	= smc_set_keepalive,
+	.hash		= smc_hash_sk,
+	.unhash		= smc_unhash_sk,
+	.release_cb	= smc_release_cb,
+	.obj_size	= sizeof(struct smc_sock),
+	.h.smc_hash	= &smc_v4_hashinfo,
+	.slab_flags	= SLAB_TYPESAFE_BY_RCU,
+};
+EXPORT_SYMBOL_GPL(smc_proto);
+
+struct proto smc_proto6 = {
+	.name		= "SMC6",
+	.owner		= THIS_MODULE,
+	.keepalive	= smc_set_keepalive,
+	.hash		= smc_hash_sk,
+	.unhash		= smc_unhash_sk,
+	.release_cb	= smc_release_cb,
+	.obj_size	= sizeof(struct smc_sock),
+	.h.smc_hash	= &smc_v6_hashinfo,
+	.slab_flags	= SLAB_TYPESAFE_BY_RCU,
+};
+EXPORT_SYMBOL_GPL(smc_proto6);
+
+static void smc_fback_restore_callbacks(struct smc_sock *smc)
+{
+	struct sock *clcsk = smc->clcsock->sk;
+
+	write_lock_bh(&clcsk->sk_callback_lock);
+	clcsk->sk_user_data = NULL;
+
+	smc_clcsock_restore_cb(&clcsk->sk_state_change, &smc->clcsk_state_change);
+	smc_clcsock_restore_cb(&clcsk->sk_data_ready, &smc->clcsk_data_ready);
+	smc_clcsock_restore_cb(&clcsk->sk_write_space, &smc->clcsk_write_space);
+	smc_clcsock_restore_cb(&clcsk->sk_error_report, &smc->clcsk_error_report);
+
+	write_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static void smc_restore_fallback_changes(struct smc_sock *smc)
+{
+	if (smc->clcsock->file) { /* non-accepted sockets have no file yet */
+		smc->clcsock->file->private_data = smc->sk.sk_socket;
+		smc->clcsock->file = NULL;
+		smc_fback_restore_callbacks(smc);
+	}
+}
+
+static int __smc_release(struct smc_sock *smc)
+{
+	struct sock *sk = &smc->sk;
+	int rc = 0;
+
+	if (!smc->use_fallback) {
+		rc = smc_close_active(smc);
+		smc_sock_set_flag(sk, SOCK_DEAD);
+		sk->sk_shutdown |= SHUTDOWN_MASK;
+	} else {
+		if (sk->sk_state != SMC_CLOSED) {
+			if (sk->sk_state != SMC_LISTEN &&
+			    sk->sk_state != SMC_INIT)
+				sock_put(sk); /* passive closing */
+			if (sk->sk_state == SMC_LISTEN) {
+				/* wake up clcsock accept */
+				rc = kernel_sock_shutdown(smc->clcsock,
+							  SHUT_RDWR);
+			}
+			sk->sk_state = SMC_CLOSED;
+			sk->sk_state_change(sk);
+		}
+		smc_restore_fallback_changes(smc);
+	}
+
+	sk->sk_prot->unhash(sk);
+
+	if (sk->sk_state == SMC_CLOSED) {
+		if (smc->clcsock) {
+			release_sock(sk);
+			smc_clcsock_release(smc);
+			lock_sock(sk);
+		}
+		if (!smc->use_fallback)
+			smc_conn_free(&smc->conn);
+	}
+
+	return rc;
+}
+
+static int smc_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int old_state, rc = 0;
+
+	if (!sk)
+		goto out;
+
+	sock_hold(sk); /* sock_put below */
+	smc = smc_sk(sk);
+
+	old_state = sk->sk_state;
+
+	/* cleanup for a dangling non-blocking connect */
+	if (smc->connect_nonblock && old_state == SMC_INIT)
+		tcp_abort(smc->clcsock->sk, ECONNABORTED);
+
+	if (cancel_work_sync(&smc->connect_work))
+		sock_put(&smc->sk); /* sock_hold in smc_connect for passive closing */
+
+	if (sk->sk_state == SMC_LISTEN)
+		/* smc_close_non_accepted() is called and acquires
+		 * sock lock for child sockets again
+		 */
+		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+	else
+		lock_sock(sk);
+
+	if (old_state == SMC_INIT && sk->sk_state == SMC_ACTIVE &&
+	    !smc->use_fallback)
+		smc_close_active_abort(smc);
+
+	rc = __smc_release(smc);
+
+	/* detach socket */
+	sock_orphan(sk);
+	sock->sk = NULL;
+	release_sock(sk);
+
+	sock_put(sk); /* sock_hold above */
+	sock_put(sk); /* final sock_put */
+out:
+	return rc;
+}
+
+static void smc_destruct(struct sock *sk)
+{
+	if (sk->sk_state != SMC_CLOSED)
+		return;
+	if (!sock_flag(sk, SOCK_DEAD))
+		return;
+
+	sk_refcnt_debug_dec(sk);
+}
+
+static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
+				   int protocol)
+{
+	struct smc_sock *smc;
+	struct proto *prot;
+	struct sock *sk;
+
+	prot = (protocol == SMCPROTO_SMC6) ? &smc_proto6 : &smc_proto;
+	sk = sk_alloc(net, PF_SMC, GFP_KERNEL, prot, 0);
+	if (!sk)
+		return NULL;
+
+	sock_init_data(sock, sk); /* sets sk_refcnt to 1 */
+	sk->sk_state = SMC_INIT;
+	sk->sk_destruct = smc_destruct;
+	sk->sk_protocol = protocol;
+	WRITE_ONCE(sk->sk_sndbuf, 2 * READ_ONCE(net->smc.sysctl_wmem));
+	WRITE_ONCE(sk->sk_rcvbuf, 2 * READ_ONCE(net->smc.sysctl_rmem));
+	smc = smc_sk(sk);
+	INIT_WORK(&smc->tcp_listen_work, smc_tcp_listen_work);
+	INIT_WORK(&smc->connect_work, smc_connect_work);
+	INIT_DELAYED_WORK(&smc->conn.tx_work, smc_tx_work);
+	INIT_LIST_HEAD(&smc->accept_q);
+	spin_lock_init(&smc->accept_q_lock);
+	spin_lock_init(&smc->conn.send_lock);
+	sk->sk_prot->hash(sk);
+	sk_refcnt_debug_inc(sk);
+	mutex_init(&smc->clcsock_release_lock);
+	smc_init_saved_callbacks(smc);
+
+	return sk;
+}
+
+static int smc_bind(struct socket *sock, struct sockaddr *uaddr,
+		    int addr_len)
+{
+	struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc;
+
+	smc = smc_sk(sk);
+
+	/* replicate tests from inet_bind(), to be safe wrt. future changes */
+	rc = -EINVAL;
+	if (addr_len < sizeof(struct sockaddr_in))
+		goto out;
+
+	rc = -EAFNOSUPPORT;
+	if (addr->sin_family != AF_INET &&
+	    addr->sin_family != AF_INET6 &&
+	    addr->sin_family != AF_UNSPEC)
+		goto out;
+	/* accept AF_UNSPEC (mapped to AF_INET) only if s_addr is INADDR_ANY */
+	if (addr->sin_family == AF_UNSPEC &&
+	    addr->sin_addr.s_addr != htonl(INADDR_ANY))
+		goto out;
+
+	lock_sock(sk);
+
+	/* Check if socket is already active */
+	rc = -EINVAL;
+	if (sk->sk_state != SMC_INIT || smc->connect_nonblock)
+		goto out_rel;
+
+	smc->clcsock->sk->sk_reuse = sk->sk_reuse;
+	smc->clcsock->sk->sk_reuseport = sk->sk_reuseport;
+	rc = kernel_bind(smc->clcsock, uaddr, addr_len);
+
+out_rel:
+	release_sock(sk);
+out:
+	return rc;
+}
+
+/* copy only relevant settings and flags of SOL_SOCKET level from smc to
+ * clc socket (since smc is not called for these options from net/core)
+ */
+
+#define SK_FLAGS_SMC_TO_CLC ((1UL << SOCK_URGINLINE) | \
+			     (1UL << SOCK_KEEPOPEN) | \
+			     (1UL << SOCK_LINGER) | \
+			     (1UL << SOCK_BROADCAST) | \
+			     (1UL << SOCK_TIMESTAMP) | \
+			     (1UL << SOCK_DBG) | \
+			     (1UL << SOCK_RCVTSTAMP) | \
+			     (1UL << SOCK_RCVTSTAMPNS) | \
+			     (1UL << SOCK_LOCALROUTE) | \
+			     (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE) | \
+			     (1UL << SOCK_RXQ_OVFL) | \
+			     (1UL << SOCK_WIFI_STATUS) | \
+			     (1UL << SOCK_NOFCS) | \
+			     (1UL << SOCK_FILTER_LOCKED) | \
+			     (1UL << SOCK_TSTAMP_NEW))
+
+/* if set, use value set by setsockopt() - else use IPv4 or SMC sysctl value */
+static void smc_adjust_sock_bufsizes(struct sock *nsk, struct sock *osk,
+				     unsigned long mask)
+{
+	struct net *nnet = sock_net(nsk);
+
+	nsk->sk_userlocks = osk->sk_userlocks;
+	if (osk->sk_userlocks & SOCK_SNDBUF_LOCK) {
+		nsk->sk_sndbuf = osk->sk_sndbuf;
+	} else {
+		if (mask == SK_FLAGS_SMC_TO_CLC)
+			WRITE_ONCE(nsk->sk_sndbuf,
+				   READ_ONCE(nnet->ipv4.sysctl_tcp_wmem[1]));
+		else
+			WRITE_ONCE(nsk->sk_sndbuf,
+				   2 * READ_ONCE(nnet->smc.sysctl_wmem));
+	}
+	if (osk->sk_userlocks & SOCK_RCVBUF_LOCK) {
+		nsk->sk_rcvbuf = osk->sk_rcvbuf;
+	} else {
+		if (mask == SK_FLAGS_SMC_TO_CLC)
+			WRITE_ONCE(nsk->sk_rcvbuf,
+				   READ_ONCE(nnet->ipv4.sysctl_tcp_rmem[1]));
+		else
+			WRITE_ONCE(nsk->sk_rcvbuf,
+				   2 * READ_ONCE(nnet->smc.sysctl_rmem));
+	}
+}
+
+static void smc_copy_sock_settings(struct sock *nsk, struct sock *osk,
+				   unsigned long mask)
+{
+	/* options we don't get control via setsockopt for */
+	nsk->sk_type = osk->sk_type;
+	nsk->sk_sndtimeo = osk->sk_sndtimeo;
+	nsk->sk_rcvtimeo = osk->sk_rcvtimeo;
+	nsk->sk_mark = READ_ONCE(osk->sk_mark);
+	nsk->sk_priority = osk->sk_priority;
+	nsk->sk_rcvlowat = osk->sk_rcvlowat;
+	nsk->sk_bound_dev_if = osk->sk_bound_dev_if;
+	nsk->sk_err = osk->sk_err;
+
+	nsk->sk_flags &= ~mask;
+	nsk->sk_flags |= osk->sk_flags & mask;
+
+	smc_adjust_sock_bufsizes(nsk, osk, mask);
+}
+
+static void smc_copy_sock_settings_to_clc(struct smc_sock *smc)
+{
+	smc_copy_sock_settings(smc->clcsock->sk, &smc->sk, SK_FLAGS_SMC_TO_CLC);
+}
+
+#define SK_FLAGS_CLC_TO_SMC ((1UL << SOCK_URGINLINE) | \
+			     (1UL << SOCK_KEEPOPEN) | \
+			     (1UL << SOCK_LINGER) | \
+			     (1UL << SOCK_DBG))
+/* copy only settings and flags relevant for smc from clc to smc socket */
+static void smc_copy_sock_settings_to_smc(struct smc_sock *smc)
+{
+	smc_copy_sock_settings(&smc->sk, smc->clcsock->sk, SK_FLAGS_CLC_TO_SMC);
+}
+
+/* register the new vzalloced sndbuf on all links */
+static int smcr_lgr_reg_sndbufs(struct smc_link *link,
+				struct smc_buf_desc *snd_desc)
+{
+	struct smc_link_group *lgr = link->lgr;
+	int i, rc = 0;
+
+	if (!snd_desc->is_vm)
+		return -EINVAL;
+
+	/* protect against parallel smcr_link_reg_buf() */
+	mutex_lock(&lgr->llc_conf_mutex);
+	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+		if (!smc_link_active(&lgr->lnk[i]))
+			continue;
+		rc = smcr_link_reg_buf(&lgr->lnk[i], snd_desc);
+		if (rc)
+			break;
+	}
+	mutex_unlock(&lgr->llc_conf_mutex);
+	return rc;
+}
+
+/* register the new rmb on all links */
+static int smcr_lgr_reg_rmbs(struct smc_link *link,
+			     struct smc_buf_desc *rmb_desc)
+{
+	struct smc_link_group *lgr = link->lgr;
+	int i, rc = 0;
+
+	rc = smc_llc_flow_initiate(lgr, SMC_LLC_FLOW_RKEY);
+	if (rc)
+		return rc;
+	/* protect against parallel smc_llc_cli_rkey_exchange() and
+	 * parallel smcr_link_reg_buf()
+	 */
+	mutex_lock(&lgr->llc_conf_mutex);
+	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+		if (!smc_link_active(&lgr->lnk[i]))
+			continue;
+		rc = smcr_link_reg_buf(&lgr->lnk[i], rmb_desc);
+		if (rc)
+			goto out;
+	}
+
+	/* exchange confirm_rkey msg with peer */
+	rc = smc_llc_do_confirm_rkey(link, rmb_desc);
+	if (rc) {
+		rc = -EFAULT;
+		goto out;
+	}
+	rmb_desc->is_conf_rkey = true;
+out:
+	mutex_unlock(&lgr->llc_conf_mutex);
+	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
+	return rc;
+}
+
+static int smcr_clnt_conf_first_link(struct smc_sock *smc)
+{
+	struct smc_link *link = smc->conn.lnk;
+	struct smc_llc_qentry *qentry;
+	int rc;
+
+	/* Receive CONFIRM LINK request from server over RoCE fabric.
+	 * Increasing the client's timeout by twice as much as the server's
+	 * timeout by default can temporarily avoid decline messages of
+	 * both sides crossing or colliding
+	 */
+	qentry = smc_llc_wait(link->lgr, NULL, 2 * SMC_LLC_WAIT_TIME,
+			      SMC_LLC_CONFIRM_LINK);
+	if (!qentry) {
+		struct smc_clc_msg_decline dclc;
+
+		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
+		return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_CL : rc;
+	}
+	smc_llc_save_peer_uid(qentry);
+	rc = smc_llc_eval_conf_link(qentry, SMC_LLC_REQ);
+	smc_llc_flow_qentry_del(&link->lgr->llc_flow_lcl);
+	if (rc)
+		return SMC_CLC_DECL_RMBE_EC;
+
+	rc = smc_ib_modify_qp_rts(link);
+	if (rc)
+		return SMC_CLC_DECL_ERR_RDYLNK;
+
+	smc_wr_remember_qp_attr(link);
+
+	/* reg the sndbuf if it was vzalloced */
+	if (smc->conn.sndbuf_desc->is_vm) {
+		if (smcr_link_reg_buf(link, smc->conn.sndbuf_desc))
+			return SMC_CLC_DECL_ERR_REGBUF;
+	}
+
+	/* reg the rmb */
+	if (smcr_link_reg_buf(link, smc->conn.rmb_desc))
+		return SMC_CLC_DECL_ERR_REGBUF;
+
+	/* confirm_rkey is implicit on 1st contact */
+	smc->conn.rmb_desc->is_conf_rkey = true;
+
+	/* send CONFIRM LINK response over RoCE fabric */
+	rc = smc_llc_send_confirm_link(link, SMC_LLC_RESP);
+	if (rc < 0)
+		return SMC_CLC_DECL_TIMEOUT_CL;
+
+	smc_llc_link_active(link);
+	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
+
+	/* optional 2nd link, receive ADD LINK request from server */
+	qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
+			      SMC_LLC_ADD_LINK);
+	if (!qentry) {
+		struct smc_clc_msg_decline dclc;
+
+		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
+		if (rc == -EAGAIN)
+			rc = 0; /* no DECLINE received, go with one link */
+		return rc;
+	}
+	smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
+	smc_llc_cli_add_link(link, qentry);
+	return 0;
+}
+
+static bool smc_isascii(char *hostname)
+{
+	int i;
+
+	for (i = 0; i < SMC_MAX_HOSTNAME_LEN; i++)
+		if (!isascii(hostname[i]))
+			return false;
+	return true;
+}
+
+static void smc_conn_save_peer_info_fce(struct smc_sock *smc,
+					struct smc_clc_msg_accept_confirm *clc)
+{
+	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
+		(struct smc_clc_msg_accept_confirm_v2 *)clc;
+	struct smc_clc_first_contact_ext *fce;
+	int clc_v2_len;
+
+	if (clc->hdr.version == SMC_V1 ||
+	    !(clc->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
+		return;
+
+	if (smc->conn.lgr->is_smcd) {
+		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->d1.eid,
+		       SMC_MAX_EID_LEN);
+		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm_v2,
+					 d1);
+	} else {
+		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->r1.eid,
+		       SMC_MAX_EID_LEN);
+		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm_v2,
+					 r1);
+	}
+	fce = (struct smc_clc_first_contact_ext *)(((u8 *)clc_v2) + clc_v2_len);
+	smc->conn.lgr->peer_os = fce->os_type;
+	smc->conn.lgr->peer_smc_release = fce->release;
+	if (smc_isascii(fce->hostname))
+		memcpy(smc->conn.lgr->peer_hostname, fce->hostname,
+		       SMC_MAX_HOSTNAME_LEN);
+}
+
+static void smcr_conn_save_peer_info(struct smc_sock *smc,
+				     struct smc_clc_msg_accept_confirm *clc)
+{
+	int bufsize = smc_uncompress_bufsize(clc->r0.rmbe_size);
+
+	smc->conn.peer_rmbe_idx = clc->r0.rmbe_idx;
+	smc->conn.local_tx_ctrl.token = ntohl(clc->r0.rmbe_alert_token);
+	smc->conn.peer_rmbe_size = bufsize;
+	atomic_set(&smc->conn.peer_rmbe_space, smc->conn.peer_rmbe_size);
+	smc->conn.tx_off = bufsize * (smc->conn.peer_rmbe_idx - 1);
+}
+
+static void smcd_conn_save_peer_info(struct smc_sock *smc,
+				     struct smc_clc_msg_accept_confirm *clc)
+{
+	int bufsize = smc_uncompress_bufsize(clc->d0.dmbe_size);
+
+	smc->conn.peer_rmbe_idx = clc->d0.dmbe_idx;
+	smc->conn.peer_token = clc->d0.token;
+	/* msg header takes up space in the buffer */
+	smc->conn.peer_rmbe_size = bufsize - sizeof(struct smcd_cdc_msg);
+	atomic_set(&smc->conn.peer_rmbe_space, smc->conn.peer_rmbe_size);
+	smc->conn.tx_off = bufsize * smc->conn.peer_rmbe_idx;
+}
+
+static void smc_conn_save_peer_info(struct smc_sock *smc,
+				    struct smc_clc_msg_accept_confirm *clc)
+{
+	if (smc->conn.lgr->is_smcd)
+		smcd_conn_save_peer_info(smc, clc);
+	else
+		smcr_conn_save_peer_info(smc, clc);
+	smc_conn_save_peer_info_fce(smc, clc);
+}
+
+static void smc_link_save_peer_info(struct smc_link *link,
+				    struct smc_clc_msg_accept_confirm *clc,
+				    struct smc_init_info *ini)
+{
+	link->peer_qpn = ntoh24(clc->r0.qpn);
+	memcpy(link->peer_gid, ini->peer_gid, SMC_GID_SIZE);
+	memcpy(link->peer_mac, ini->peer_mac, sizeof(link->peer_mac));
+	link->peer_psn = ntoh24(clc->r0.psn);
+	link->peer_mtu = clc->r0.qp_mtu;
+}
+
+static void smc_stat_inc_fback_rsn_cnt(struct smc_sock *smc,
+				       struct smc_stats_fback *fback_arr)
+{
+	int cnt;
+
+	for (cnt = 0; cnt < SMC_MAX_FBACK_RSN_CNT; cnt++) {
+		if (fback_arr[cnt].fback_code == smc->fallback_rsn) {
+			fback_arr[cnt].count++;
+			break;
+		}
+		if (!fback_arr[cnt].fback_code) {
+			fback_arr[cnt].fback_code = smc->fallback_rsn;
+			fback_arr[cnt].count++;
+			break;
+		}
+	}
+}
+
+static void smc_stat_fallback(struct smc_sock *smc)
+{
+	struct net *net = sock_net(&smc->sk);
+
+	mutex_lock(&net->smc.mutex_fback_rsn);
+	if (smc->listen_smc) {
+		smc_stat_inc_fback_rsn_cnt(smc, net->smc.fback_rsn->srv);
+		net->smc.fback_rsn->srv_fback_cnt++;
+	} else {
+		smc_stat_inc_fback_rsn_cnt(smc, net->smc.fback_rsn->clnt);
+		net->smc.fback_rsn->clnt_fback_cnt++;
+	}
+	mutex_unlock(&net->smc.mutex_fback_rsn);
+}
+
+/* must be called under rcu read lock */
+static void smc_fback_wakeup_waitqueue(struct smc_sock *smc, void *key)
+{
+	struct socket_wq *wq;
+	__poll_t flags;
+
+	wq = rcu_dereference(smc->sk.sk_wq);
+	if (!skwq_has_sleeper(wq))
+		return;
+
+	/* wake up smc sk->sk_wq */
+	if (!key) {
+		/* sk_state_change */
+		wake_up_interruptible_all(&wq->wait);
+	} else {
+		flags = key_to_poll(key);
+		if (flags & (EPOLLIN | EPOLLOUT))
+			/* sk_data_ready or sk_write_space */
+			wake_up_interruptible_sync_poll(&wq->wait, flags);
+		else if (flags & EPOLLERR)
+			/* sk_error_report */
+			wake_up_interruptible_poll(&wq->wait, flags);
+	}
+}
+
+static int smc_fback_mark_woken(wait_queue_entry_t *wait,
+				unsigned int mode, int sync, void *key)
+{
+	struct smc_mark_woken *mark =
+		container_of(wait, struct smc_mark_woken, wait_entry);
+
+	mark->woken = true;
+	mark->key = key;
+	return 0;
+}
+
+static void smc_fback_forward_wakeup(struct smc_sock *smc, struct sock *clcsk,
+				     void (*clcsock_callback)(struct sock *sk))
+{
+	struct smc_mark_woken mark = { .woken = false };
+	struct socket_wq *wq;
+
+	init_waitqueue_func_entry(&mark.wait_entry,
+				  smc_fback_mark_woken);
+	rcu_read_lock();
+	wq = rcu_dereference(clcsk->sk_wq);
+	if (!wq)
+		goto out;
+	add_wait_queue(sk_sleep(clcsk), &mark.wait_entry);
+	clcsock_callback(clcsk);
+	remove_wait_queue(sk_sleep(clcsk), &mark.wait_entry);
+
+	if (mark.woken)
+		smc_fback_wakeup_waitqueue(smc, mark.key);
+out:
+	rcu_read_unlock();
+}
+
+static void smc_fback_state_change(struct sock *clcsk)
+{
+	struct smc_sock *smc;
+
+	read_lock_bh(&clcsk->sk_callback_lock);
+	smc = smc_clcsock_user_data(clcsk);
+	if (smc)
+		smc_fback_forward_wakeup(smc, clcsk,
+					 smc->clcsk_state_change);
+	read_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static void smc_fback_data_ready(struct sock *clcsk)
+{
+	struct smc_sock *smc;
+
+	read_lock_bh(&clcsk->sk_callback_lock);
+	smc = smc_clcsock_user_data(clcsk);
+	if (smc)
+		smc_fback_forward_wakeup(smc, clcsk,
+					 smc->clcsk_data_ready);
+	read_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static void smc_fback_write_space(struct sock *clcsk)
+{
+	struct smc_sock *smc;
+
+	read_lock_bh(&clcsk->sk_callback_lock);
+	smc = smc_clcsock_user_data(clcsk);
+	if (smc)
+		smc_fback_forward_wakeup(smc, clcsk,
+					 smc->clcsk_write_space);
+	read_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static void smc_fback_error_report(struct sock *clcsk)
+{
+	struct smc_sock *smc;
+
+	read_lock_bh(&clcsk->sk_callback_lock);
+	smc = smc_clcsock_user_data(clcsk);
+	if (smc)
+		smc_fback_forward_wakeup(smc, clcsk,
+					 smc->clcsk_error_report);
+	read_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static void smc_fback_replace_callbacks(struct smc_sock *smc)
+{
+	struct sock *clcsk = smc->clcsock->sk;
+
+	write_lock_bh(&clcsk->sk_callback_lock);
+	clcsk->sk_user_data = (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY);
+
+	smc_clcsock_replace_cb(&clcsk->sk_state_change, smc_fback_state_change,
+			       &smc->clcsk_state_change);
+	smc_clcsock_replace_cb(&clcsk->sk_data_ready, smc_fback_data_ready,
+			       &smc->clcsk_data_ready);
+	smc_clcsock_replace_cb(&clcsk->sk_write_space, smc_fback_write_space,
+			       &smc->clcsk_write_space);
+	smc_clcsock_replace_cb(&clcsk->sk_error_report, smc_fback_error_report,
+			       &smc->clcsk_error_report);
+
+	write_unlock_bh(&clcsk->sk_callback_lock);
+}
+
+static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code)
+{
+	int rc = 0;
+
+	mutex_lock(&smc->clcsock_release_lock);
+	if (!smc->clcsock) {
+		rc = -EBADF;
+		goto out;
+	}
+
+	smc->use_fallback = true;
+	smc->fallback_rsn = reason_code;
+	smc_stat_fallback(smc);
+	trace_smc_switch_to_fallback(smc, reason_code);
+	if (smc->sk.sk_socket && smc->sk.sk_socket->file) {
+		smc->clcsock->file = smc->sk.sk_socket->file;
+		smc->clcsock->file->private_data = smc->clcsock;
+		smc->clcsock->wq.fasync_list =
+			smc->sk.sk_socket->wq.fasync_list;
+
+		/* There might be some wait entries remaining
+		 * in smc sk->sk_wq and they should be woken up
+		 * as clcsock's wait queue is woken up.
+		 */
+		smc_fback_replace_callbacks(smc);
+	}
+out:
+	mutex_unlock(&smc->clcsock_release_lock);
+	return rc;
+}
+
+/* fall back during connect */
+static int smc_connect_fallback(struct smc_sock *smc, int reason_code)
+{
+	struct net *net = sock_net(&smc->sk);
+	int rc = 0;
+
+	rc = smc_switch_to_fallback(smc, reason_code);
+	if (rc) { /* fallback fails */
+		this_cpu_inc(net->smc.smc_stats->clnt_hshake_err_cnt);
+		if (smc->sk.sk_state == SMC_INIT)
+			sock_put(&smc->sk); /* passive closing */
+		return rc;
+	}
+	smc_copy_sock_settings_to_clc(smc);
+	smc->connect_nonblock = 0;
+	if (smc->sk.sk_state == SMC_INIT)
+		smc->sk.sk_state = SMC_ACTIVE;
+	return 0;
+}
+
+/* decline and fall back during connect */
+static int smc_connect_decline_fallback(struct smc_sock *smc, int reason_code,
+					u8 version)
+{
+	struct net *net = sock_net(&smc->sk);
+	int rc;
+
+	if (reason_code < 0) { /* error, fallback is not possible */
+		this_cpu_inc(net->smc.smc_stats->clnt_hshake_err_cnt);
+		if (smc->sk.sk_state == SMC_INIT)
+			sock_put(&smc->sk); /* passive closing */
+		return reason_code;
+	}
+	if (reason_code != SMC_CLC_DECL_PEERDECL) {
+		rc = smc_clc_send_decline(smc, reason_code, version);
+		if (rc < 0) {
+			this_cpu_inc(net->smc.smc_stats->clnt_hshake_err_cnt);
+			if (smc->sk.sk_state == SMC_INIT)
+				sock_put(&smc->sk); /* passive closing */
+			return rc;
+		}
+	}
+	return smc_connect_fallback(smc, reason_code);
+}
+
+static void smc_conn_abort(struct smc_sock *smc, int local_first)
+{
+	struct smc_connection *conn = &smc->conn;
+	struct smc_link_group *lgr = conn->lgr;
+	bool lgr_valid = false;
+
+	if (smc_conn_lgr_valid(conn))
+		lgr_valid = true;
+
+	smc_conn_free(conn);
+	if (local_first && lgr_valid)
+		smc_lgr_cleanup_early(lgr);
+}
+
+/* check if there is a rdma device available for this connection. */
+/* called for connect and listen */
+static int smc_find_rdma_device(struct smc_sock *smc, struct smc_init_info *ini)
+{
+	/* PNET table look up: search active ib_device and port
+	 * within same PNETID that also contains the ethernet device
+	 * used for the internal TCP socket
+	 */
+	smc_pnet_find_roce_resource(smc->clcsock->sk, ini);
+	if (!ini->check_smcrv2 && !ini->ib_dev)
+		return SMC_CLC_DECL_NOSMCRDEV;
+	if (ini->check_smcrv2 && !ini->smcrv2.ib_dev_v2)
+		return SMC_CLC_DECL_NOSMCRDEV;
+	return 0;
+}
+
+/* check if there is an ISM device available for this connection. */
+/* called for connect and listen */
+static int smc_find_ism_device(struct smc_sock *smc, struct smc_init_info *ini)
+{
+	/* Find ISM device with same PNETID as connecting interface  */
+	smc_pnet_find_ism_resource(smc->clcsock->sk, ini);
+	if (!ini->ism_dev[0])
+		return SMC_CLC_DECL_NOSMCDDEV;
+	else
+		ini->ism_chid[0] = smc_ism_get_chid(ini->ism_dev[0]);
+	return 0;
+}
+
+/* is chid unique for the ism devices that are already determined? */
+static bool smc_find_ism_v2_is_unique_chid(u16 chid, struct smc_init_info *ini,
+					   int cnt)
+{
+	int i = (!ini->ism_dev[0]) ? 1 : 0;
+
+	for (; i < cnt; i++)
+		if (ini->ism_chid[i] == chid)
+			return false;
+	return true;
+}
+
+/* determine possible V2 ISM devices (either without PNETID or with PNETID plus
+ * PNETID matching net_device)
+ */
+static int smc_find_ism_v2_device_clnt(struct smc_sock *smc,
+				       struct smc_init_info *ini)
+{
+	int rc = SMC_CLC_DECL_NOSMCDDEV;
+	struct smcd_dev *smcd;
+	int i = 1;
+	u16 chid;
+
+	if (smcd_indicated(ini->smc_type_v1))
+		rc = 0;		/* already initialized for V1 */
+	mutex_lock(&smcd_dev_list.mutex);
+	list_for_each_entry(smcd, &smcd_dev_list.list, list) {
+		if (smcd->going_away || smcd == ini->ism_dev[0])
+			continue;
+		chid = smc_ism_get_chid(smcd);
+		if (!smc_find_ism_v2_is_unique_chid(chid, ini, i))
+			continue;
+		if (!smc_pnet_is_pnetid_set(smcd->pnetid) ||
+		    smc_pnet_is_ndev_pnetid(sock_net(&smc->sk), smcd->pnetid)) {
+			ini->ism_dev[i] = smcd;
+			ini->ism_chid[i] = chid;
+			ini->is_smcd = true;
+			rc = 0;
+			i++;
+			if (i > SMC_MAX_ISM_DEVS)
+				break;
+		}
+	}
+	mutex_unlock(&smcd_dev_list.mutex);
+	ini->ism_offered_cnt = i - 1;
+	if (!ini->ism_dev[0] && !ini->ism_dev[1])
+		ini->smcd_version = 0;
+
+	return rc;
+}
+
+/* Check for VLAN ID and register it on ISM device just for CLC handshake */
+static int smc_connect_ism_vlan_setup(struct smc_sock *smc,
+				      struct smc_init_info *ini)
+{
+	if (ini->vlan_id && smc_ism_get_vlan(ini->ism_dev[0], ini->vlan_id))
+		return SMC_CLC_DECL_ISMVLANERR;
+	return 0;
+}
+
+static int smc_find_proposal_devices(struct smc_sock *smc,
+				     struct smc_init_info *ini)
+{
+	int rc = 0;
+
+	/* check if there is an ism device available */
+	if (!(ini->smcd_version & SMC_V1) ||
+	    smc_find_ism_device(smc, ini) ||
+	    smc_connect_ism_vlan_setup(smc, ini))
+		ini->smcd_version &= ~SMC_V1;
+	/* else ISM V1 is supported for this connection */
+
+	/* check if there is an rdma device available */
+	if (!(ini->smcr_version & SMC_V1) ||
+	    smc_find_rdma_device(smc, ini))
+		ini->smcr_version &= ~SMC_V1;
+	/* else RDMA is supported for this connection */
+
+	ini->smc_type_v1 = smc_indicated_type(ini->smcd_version & SMC_V1,
+					      ini->smcr_version & SMC_V1);
+
+	/* check if there is an ism v2 device available */
+	if (!(ini->smcd_version & SMC_V2) ||
+	    !smc_ism_is_v2_capable() ||
+	    smc_find_ism_v2_device_clnt(smc, ini))
+		ini->smcd_version &= ~SMC_V2;
+
+	/* check if there is an rdma v2 device available */
+	ini->check_smcrv2 = true;
+	ini->smcrv2.saddr = smc->clcsock->sk->sk_rcv_saddr;
+	if (!(ini->smcr_version & SMC_V2) ||
+	    smc->clcsock->sk->sk_family != AF_INET ||
+	    !smc_clc_ueid_count() ||
+	    smc_find_rdma_device(smc, ini))
+		ini->smcr_version &= ~SMC_V2;
+	ini->check_smcrv2 = false;
+
+	ini->smc_type_v2 = smc_indicated_type(ini->smcd_version & SMC_V2,
+					      ini->smcr_version & SMC_V2);
+
+	/* if neither ISM nor RDMA are supported, fallback */
+	if (ini->smc_type_v1 == SMC_TYPE_N && ini->smc_type_v2 == SMC_TYPE_N)
+		rc = SMC_CLC_DECL_NOSMCDEV;
+
+	return rc;
+}
+
+/* cleanup temporary VLAN ID registration used for CLC handshake. If ISM is
+ * used, the VLAN ID will be registered again during the connection setup.
+ */
+static int smc_connect_ism_vlan_cleanup(struct smc_sock *smc,
+					struct smc_init_info *ini)
+{
+	if (!smcd_indicated(ini->smc_type_v1))
+		return 0;
+	if (ini->vlan_id && smc_ism_put_vlan(ini->ism_dev[0], ini->vlan_id))
+		return SMC_CLC_DECL_CNFERR;
+	return 0;
+}
+
+#define SMC_CLC_MAX_ACCEPT_LEN \
+	(sizeof(struct smc_clc_msg_accept_confirm_v2) + \
+	 sizeof(struct smc_clc_first_contact_ext) + \
+	 sizeof(struct smc_clc_msg_trail))
+
+/* CLC handshake during connect */
+static int smc_connect_clc(struct smc_sock *smc,
+			   struct smc_clc_msg_accept_confirm_v2 *aclc2,
+			   struct smc_init_info *ini)
+{
+	int rc = 0;
+
+	/* do inband token exchange */
+	rc = smc_clc_send_proposal(smc, ini);
+	if (rc)
+		return rc;
+	/* receive SMC Accept CLC message */
+	return smc_clc_wait_msg(smc, aclc2, SMC_CLC_MAX_ACCEPT_LEN,
+				SMC_CLC_ACCEPT, CLC_WAIT_TIME);
+}
+
+void smc_fill_gid_list(struct smc_link_group *lgr,
+		       struct smc_gidlist *gidlist,
+		       struct smc_ib_device *known_dev, u8 *known_gid)
+{
+	struct smc_init_info *alt_ini = NULL;
+
+	memset(gidlist, 0, sizeof(*gidlist));
+	memcpy(gidlist->list[gidlist->len++], known_gid, SMC_GID_SIZE);
+
+	alt_ini = kzalloc(sizeof(*alt_ini), GFP_KERNEL);
+	if (!alt_ini)
+		goto out;
+
+	alt_ini->vlan_id = lgr->vlan_id;
+	alt_ini->check_smcrv2 = true;
+	alt_ini->smcrv2.saddr = lgr->saddr;
+	smc_pnet_find_alt_roce(lgr, alt_ini, known_dev);
+
+	if (!alt_ini->smcrv2.ib_dev_v2)
+		goto out;
+
+	memcpy(gidlist->list[gidlist->len++], alt_ini->smcrv2.ib_gid_v2,
+	       SMC_GID_SIZE);
+
+out:
+	kfree(alt_ini);
+}
+
+static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
+				       struct smc_clc_msg_accept_confirm *aclc,
+				       struct smc_init_info *ini)
+{
+	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
+		(struct smc_clc_msg_accept_confirm_v2 *)aclc;
+	struct smc_clc_first_contact_ext *fce =
+		(struct smc_clc_first_contact_ext *)
+			(((u8 *)clc_v2) + sizeof(*clc_v2));
+	struct net *net = sock_net(&smc->sk);
+
+	if (!ini->first_contact_peer || aclc->hdr.version == SMC_V1)
+		return 0;
+
+	if (fce->v2_direct) {
+		memcpy(ini->smcrv2.nexthop_mac, &aclc->r0.lcl.mac, ETH_ALEN);
+		ini->smcrv2.uses_gateway = false;
+	} else {
+		if (smc_ib_find_route(net, smc->clcsock->sk->sk_rcv_saddr,
+				      smc_ib_gid_to_ipv4(aclc->r0.lcl.gid),
+				      ini->smcrv2.nexthop_mac,
+				      &ini->smcrv2.uses_gateway))
+			return SMC_CLC_DECL_NOROUTE;
+		if (!ini->smcrv2.uses_gateway) {
+			/* mismatch: peer claims indirect, but its direct */
+			return SMC_CLC_DECL_NOINDIRECT;
+		}
+	}
+	return 0;
+}
+
+/* setup for RDMA connection of client */
+static int smc_connect_rdma(struct smc_sock *smc,
+			    struct smc_clc_msg_accept_confirm *aclc,
+			    struct smc_init_info *ini)
+{
+	int i, reason_code = 0;
+	struct smc_link *link;
+	u8 *eid = NULL;
+
+	ini->is_smcd = false;
+	ini->ib_clcqpn = ntoh24(aclc->r0.qpn);
+	ini->first_contact_peer = aclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK;
+	memcpy(ini->peer_systemid, aclc->r0.lcl.id_for_peer, SMC_SYSTEMID_LEN);
+	memcpy(ini->peer_gid, aclc->r0.lcl.gid, SMC_GID_SIZE);
+	memcpy(ini->peer_mac, aclc->r0.lcl.mac, ETH_ALEN);
+
+	reason_code = smc_connect_rdma_v2_prepare(smc, aclc, ini);
+	if (reason_code)
+		return reason_code;
+
+	mutex_lock(&smc_client_lgr_pending);
+	reason_code = smc_conn_create(smc, ini);
+	if (reason_code) {
+		mutex_unlock(&smc_client_lgr_pending);
+		return reason_code;
+	}
+
+	smc_conn_save_peer_info(smc, aclc);
+
+	if (ini->first_contact_local) {
+		link = smc->conn.lnk;
+	} else {
+		/* set link that was assigned by server */
+		link = NULL;
+		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+			struct smc_link *l = &smc->conn.lgr->lnk[i];
+
+			if (l->peer_qpn == ntoh24(aclc->r0.qpn) &&
+			    !memcmp(l->peer_gid, &aclc->r0.lcl.gid,
+				    SMC_GID_SIZE) &&
+			    (aclc->hdr.version > SMC_V1 ||
+			     !memcmp(l->peer_mac, &aclc->r0.lcl.mac,
+				     sizeof(l->peer_mac)))) {
+				link = l;
+				break;
+			}
+		}
+		if (!link) {
+			reason_code = SMC_CLC_DECL_NOSRVLINK;
+			goto connect_abort;
+		}
+		smc_switch_link_and_count(&smc->conn, link);
+	}
+
+	/* create send buffer and rmb */
+	if (smc_buf_create(smc, false)) {
+		reason_code = SMC_CLC_DECL_MEM;
+		goto connect_abort;
+	}
+
+	if (ini->first_contact_local)
+		smc_link_save_peer_info(link, aclc, ini);
+
+	if (smc_rmb_rtoken_handling(&smc->conn, link, aclc)) {
+		reason_code = SMC_CLC_DECL_ERR_RTOK;
+		goto connect_abort;
+	}
+
+	smc_close_init(smc);
+	smc_rx_init(smc);
+
+	if (ini->first_contact_local) {
+		if (smc_ib_ready_link(link)) {
+			reason_code = SMC_CLC_DECL_ERR_RDYLNK;
+			goto connect_abort;
+		}
+	} else {
+		/* reg sendbufs if they were vzalloced */
+		if (smc->conn.sndbuf_desc->is_vm) {
+			if (smcr_lgr_reg_sndbufs(link, smc->conn.sndbuf_desc)) {
+				reason_code = SMC_CLC_DECL_ERR_REGBUF;
+				goto connect_abort;
+			}
+		}
+		if (smcr_lgr_reg_rmbs(link, smc->conn.rmb_desc)) {
+			reason_code = SMC_CLC_DECL_ERR_REGBUF;
+			goto connect_abort;
+		}
+	}
+
+	if (aclc->hdr.version > SMC_V1) {
+		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
+			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
+
+		eid = clc_v2->r1.eid;
+		if (ini->first_contact_local)
+			smc_fill_gid_list(link->lgr, &ini->smcrv2.gidlist,
+					  link->smcibdev, link->gid);
+	}
+
+	reason_code = smc_clc_send_confirm(smc, ini->first_contact_local,
+					   aclc->hdr.version, eid, ini);
+	if (reason_code)
+		goto connect_abort;
+
+	smc_tx_init(smc);
+
+	if (ini->first_contact_local) {
+		/* QP confirmation over RoCE fabric */
+		smc_llc_flow_initiate(link->lgr, SMC_LLC_FLOW_ADD_LINK);
+		reason_code = smcr_clnt_conf_first_link(smc);
+		smc_llc_flow_stop(link->lgr, &link->lgr->llc_flow_lcl);
+		if (reason_code)
+			goto connect_abort;
+	}
+	mutex_unlock(&smc_client_lgr_pending);
+
+	smc_copy_sock_settings_to_clc(smc);
+	smc->connect_nonblock = 0;
+	if (smc->sk.sk_state == SMC_INIT)
+		smc->sk.sk_state = SMC_ACTIVE;
+
+	return 0;
+connect_abort:
+	smc_conn_abort(smc, ini->first_contact_local);
+	mutex_unlock(&smc_client_lgr_pending);
+	smc->connect_nonblock = 0;
+
+	return reason_code;
+}
+
+/* The server has chosen one of the proposed ISM devices for the communication.
+ * Determine from the CHID of the received CLC ACCEPT the ISM device chosen.
+ */
+static int
+smc_v2_determine_accepted_chid(struct smc_clc_msg_accept_confirm_v2 *aclc,
+			       struct smc_init_info *ini)
+{
+	int i;
+
+	for (i = 0; i < ini->ism_offered_cnt + 1; i++) {
+		if (ini->ism_chid[i] == ntohs(aclc->d1.chid)) {
+			ini->ism_selected = i;
+			return 0;
+		}
+	}
+
+	return -EPROTO;
+}
+
+/* setup for ISM connection of client */
+static int smc_connect_ism(struct smc_sock *smc,
+			   struct smc_clc_msg_accept_confirm *aclc,
+			   struct smc_init_info *ini)
+{
+	u8 *eid = NULL;
+	int rc = 0;
+
+	ini->is_smcd = true;
+	ini->first_contact_peer = aclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK;
+
+	if (aclc->hdr.version == SMC_V2) {
+		struct smc_clc_msg_accept_confirm_v2 *aclc_v2 =
+			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
+
+		rc = smc_v2_determine_accepted_chid(aclc_v2, ini);
+		if (rc)
+			return rc;
+	}
+	ini->ism_peer_gid[ini->ism_selected] = aclc->d0.gid;
+
+	/* there is only one lgr role for SMC-D; use server lock */
+	mutex_lock(&smc_server_lgr_pending);
+	rc = smc_conn_create(smc, ini);
+	if (rc) {
+		mutex_unlock(&smc_server_lgr_pending);
+		return rc;
+	}
+
+	/* Create send and receive buffers */
+	rc = smc_buf_create(smc, true);
+	if (rc) {
+		rc = (rc == -ENOSPC) ? SMC_CLC_DECL_MAX_DMB : SMC_CLC_DECL_MEM;
+		goto connect_abort;
+	}
+
+	smc_conn_save_peer_info(smc, aclc);
+	smc_close_init(smc);
+	smc_rx_init(smc);
+	smc_tx_init(smc);
+
+	if (aclc->hdr.version > SMC_V1) {
+		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
+			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
+
+		eid = clc_v2->d1.eid;
+	}
+
+	rc = smc_clc_send_confirm(smc, ini->first_contact_local,
+				  aclc->hdr.version, eid, NULL);
+	if (rc)
+		goto connect_abort;
+	mutex_unlock(&smc_server_lgr_pending);
+
+	smc_copy_sock_settings_to_clc(smc);
+	smc->connect_nonblock = 0;
+	if (smc->sk.sk_state == SMC_INIT)
+		smc->sk.sk_state = SMC_ACTIVE;
+
+	return 0;
+connect_abort:
+	smc_conn_abort(smc, ini->first_contact_local);
+	mutex_unlock(&smc_server_lgr_pending);
+	smc->connect_nonblock = 0;
+
+	return rc;
+}
+
+/* check if received accept type and version matches a proposed one */
+static int smc_connect_check_aclc(struct smc_init_info *ini,
+				  struct smc_clc_msg_accept_confirm *aclc)
+{
+	if (aclc->hdr.typev1 != SMC_TYPE_R &&
+	    aclc->hdr.typev1 != SMC_TYPE_D)
+		return SMC_CLC_DECL_MODEUNSUPP;
+
+	if (aclc->hdr.version >= SMC_V2) {
+		if ((aclc->hdr.typev1 == SMC_TYPE_R &&
+		     !smcr_indicated(ini->smc_type_v2)) ||
+		    (aclc->hdr.typev1 == SMC_TYPE_D &&
+		     !smcd_indicated(ini->smc_type_v2)))
+			return SMC_CLC_DECL_MODEUNSUPP;
+	} else {
+		if ((aclc->hdr.typev1 == SMC_TYPE_R &&
+		     !smcr_indicated(ini->smc_type_v1)) ||
+		    (aclc->hdr.typev1 == SMC_TYPE_D &&
+		     !smcd_indicated(ini->smc_type_v1)))
+			return SMC_CLC_DECL_MODEUNSUPP;
+	}
+
+	return 0;
+}
+
+/* perform steps before actually connecting */
+static int __smc_connect(struct smc_sock *smc)
+{
+	u8 version = smc_ism_is_v2_capable() ? SMC_V2 : SMC_V1;
+	struct smc_clc_msg_accept_confirm_v2 *aclc2;
+	struct smc_clc_msg_accept_confirm *aclc;
+	struct smc_init_info *ini = NULL;
+	u8 *buf = NULL;
+	int rc = 0;
+
+	if (smc->use_fallback)
+		return smc_connect_fallback(smc, smc->fallback_rsn);
+
+	/* if peer has not signalled SMC-capability, fall back */
+	if (!tcp_sk(smc->clcsock->sk)->syn_smc)
+		return smc_connect_fallback(smc, SMC_CLC_DECL_PEERNOSMC);
+
+	/* IPSec connections opt out of SMC optimizations */
+	if (using_ipsec(smc))
+		return smc_connect_decline_fallback(smc, SMC_CLC_DECL_IPSEC,
+						    version);
+
+	ini = kzalloc(sizeof(*ini), GFP_KERNEL);
+	if (!ini)
+		return smc_connect_decline_fallback(smc, SMC_CLC_DECL_MEM,
+						    version);
+
+	ini->smcd_version = SMC_V1 | SMC_V2;
+	ini->smcr_version = SMC_V1 | SMC_V2;
+	ini->smc_type_v1 = SMC_TYPE_B;
+	ini->smc_type_v2 = SMC_TYPE_B;
+
+	/* get vlan id from IP device */
+	if (smc_vlan_by_tcpsk(smc->clcsock, ini)) {
+		ini->smcd_version &= ~SMC_V1;
+		ini->smcr_version = 0;
+		ini->smc_type_v1 = SMC_TYPE_N;
+		if (!ini->smcd_version) {
+			rc = SMC_CLC_DECL_GETVLANERR;
+			goto fallback;
+		}
+	}
+
+	rc = smc_find_proposal_devices(smc, ini);
+	if (rc)
+		goto fallback;
+
+	buf = kzalloc(SMC_CLC_MAX_ACCEPT_LEN, GFP_KERNEL);
+	if (!buf) {
+		rc = SMC_CLC_DECL_MEM;
+		goto fallback;
+	}
+	aclc2 = (struct smc_clc_msg_accept_confirm_v2 *)buf;
+	aclc = (struct smc_clc_msg_accept_confirm *)aclc2;
+
+	/* perform CLC handshake */
+	rc = smc_connect_clc(smc, aclc2, ini);
+	if (rc) {
+		/* -EAGAIN on timeout, see tcp_recvmsg() */
+		if (rc == -EAGAIN) {
+			rc = -ETIMEDOUT;
+			smc->sk.sk_err = ETIMEDOUT;
+		}
+		goto vlan_cleanup;
+	}
+
+	/* check if smc modes and versions of CLC proposal and accept match */
+	rc = smc_connect_check_aclc(ini, aclc);
+	version = aclc->hdr.version == SMC_V1 ? SMC_V1 : SMC_V2;
+	if (rc)
+		goto vlan_cleanup;
+
+	/* depending on previous steps, connect using rdma or ism */
+	if (aclc->hdr.typev1 == SMC_TYPE_R) {
+		ini->smcr_version = version;
+		rc = smc_connect_rdma(smc, aclc, ini);
+	} else if (aclc->hdr.typev1 == SMC_TYPE_D) {
+		ini->smcd_version = version;
+		rc = smc_connect_ism(smc, aclc, ini);
+	}
+	if (rc)
+		goto vlan_cleanup;
+
+	SMC_STAT_CLNT_SUCC_INC(sock_net(smc->clcsock->sk), aclc);
+	smc_connect_ism_vlan_cleanup(smc, ini);
+	kfree(buf);
+	kfree(ini);
+	return 0;
+
+vlan_cleanup:
+	smc_connect_ism_vlan_cleanup(smc, ini);
+	kfree(buf);
+fallback:
+	kfree(ini);
+	return smc_connect_decline_fallback(smc, rc, version);
+}
+
+static void smc_connect_work(struct work_struct *work)
+{
+	struct smc_sock *smc = container_of(work, struct smc_sock,
+					    connect_work);
+	long timeo = smc->sk.sk_sndtimeo;
+	int rc = 0;
+
+	if (!timeo)
+		timeo = MAX_SCHEDULE_TIMEOUT;
+	lock_sock(smc->clcsock->sk);
+	if (smc->clcsock->sk->sk_err) {
+		smc->sk.sk_err = smc->clcsock->sk->sk_err;
+	} else if ((1 << smc->clcsock->sk->sk_state) &
+					(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
+		rc = sk_stream_wait_connect(smc->clcsock->sk, &timeo);
+		if ((rc == -EPIPE) &&
+		    ((1 << smc->clcsock->sk->sk_state) &
+					(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)))
+			rc = 0;
+	}
+	release_sock(smc->clcsock->sk);
+	lock_sock(&smc->sk);
+	if (rc != 0 || smc->sk.sk_err) {
+		smc->sk.sk_state = SMC_CLOSED;
+		if (rc == -EPIPE || rc == -EAGAIN)
+			smc->sk.sk_err = EPIPE;
+		else if (rc == -ECONNREFUSED)
+			smc->sk.sk_err = ECONNREFUSED;
+		else if (signal_pending(current))
+			smc->sk.sk_err = -sock_intr_errno(timeo);
+		sock_put(&smc->sk); /* passive closing */
+		goto out;
+	}
+
+	rc = __smc_connect(smc);
+	if (rc < 0)
+		smc->sk.sk_err = -rc;
+
+out:
+	if (!sock_flag(&smc->sk, SOCK_DEAD)) {
+		if (smc->sk.sk_err) {
+			smc->sk.sk_state_change(&smc->sk);
+		} else { /* allow polling before and after fallback decision */
+			smc->clcsock->sk->sk_write_space(smc->clcsock->sk);
+			smc->sk.sk_write_space(&smc->sk);
+		}
+	}
+	release_sock(&smc->sk);
+}
+
+static int smc_connect(struct socket *sock, struct sockaddr *addr,
+		       int alen, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc = -EINVAL;
+
+	smc = smc_sk(sk);
+
+	/* separate smc parameter checking to be safe */
+	if (alen < sizeof(addr->sa_family))
+		goto out_err;
+	if (addr->sa_family != AF_INET && addr->sa_family != AF_INET6)
+		goto out_err;
+
+	lock_sock(sk);
+	switch (sock->state) {
+	default:
+		rc = -EINVAL;
+		goto out;
+	case SS_CONNECTED:
+		rc = sk->sk_state == SMC_ACTIVE ? -EISCONN : -EINVAL;
+		goto out;
+	case SS_CONNECTING:
+		if (sk->sk_state == SMC_ACTIVE)
+			goto connected;
+		break;
+	case SS_UNCONNECTED:
+		sock->state = SS_CONNECTING;
+		break;
+	}
+
+	switch (sk->sk_state) {
+	default:
+		goto out;
+	case SMC_CLOSED:
+		rc = sock_error(sk) ? : -ECONNABORTED;
+		sock->state = SS_UNCONNECTED;
+		goto out;
+	case SMC_ACTIVE:
+		rc = -EISCONN;
+		goto out;
+	case SMC_INIT:
+		break;
+	}
+
+	smc_copy_sock_settings_to_clc(smc);
+	tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+	if (smc->connect_nonblock) {
+		rc = -EALREADY;
+		goto out;
+	}
+	rc = kernel_connect(smc->clcsock, addr, alen, flags);
+	if (rc && rc != -EINPROGRESS)
+		goto out;
+
+	if (smc->use_fallback) {
+		sock->state = rc ? SS_CONNECTING : SS_CONNECTED;
+		goto out;
+	}
+	sock_hold(&smc->sk); /* sock put in passive closing */
+	if (flags & O_NONBLOCK) {
+		if (queue_work(smc_hs_wq, &smc->connect_work))
+			smc->connect_nonblock = 1;
+		rc = -EINPROGRESS;
+		goto out;
+	} else {
+		rc = __smc_connect(smc);
+		if (rc < 0)
+			goto out;
+	}
+
+connected:
+	rc = 0;
+	sock->state = SS_CONNECTED;
+out:
+	release_sock(sk);
+out_err:
+	return rc;
+}
+
+static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
+{
+	struct socket *new_clcsock = NULL;
+	struct sock *lsk = &lsmc->sk;
+	struct sock *new_sk;
+	int rc = -EINVAL;
+
+	release_sock(lsk);
+	new_sk = smc_sock_alloc(sock_net(lsk), NULL, lsk->sk_protocol);
+	if (!new_sk) {
+		rc = -ENOMEM;
+		lsk->sk_err = ENOMEM;
+		*new_smc = NULL;
+		lock_sock(lsk);
+		goto out;
+	}
+	*new_smc = smc_sk(new_sk);
+
+	mutex_lock(&lsmc->clcsock_release_lock);
+	if (lsmc->clcsock)
+		rc = kernel_accept(lsmc->clcsock, &new_clcsock, SOCK_NONBLOCK);
+	mutex_unlock(&lsmc->clcsock_release_lock);
+	lock_sock(lsk);
+	if  (rc < 0 && rc != -EAGAIN)
+		lsk->sk_err = -rc;
+	if (rc < 0 || lsk->sk_state == SMC_CLOSED) {
+		new_sk->sk_prot->unhash(new_sk);
+		if (new_clcsock)
+			sock_release(new_clcsock);
+		new_sk->sk_state = SMC_CLOSED;
+		smc_sock_set_flag(new_sk, SOCK_DEAD);
+		sock_put(new_sk); /* final */
+		*new_smc = NULL;
+		goto out;
+	}
+
+	/* new clcsock has inherited the smc listen-specific sk_data_ready
+	 * function; switch it back to the original sk_data_ready function
+	 */
+	new_clcsock->sk->sk_data_ready = lsmc->clcsk_data_ready;
+
+	/* if new clcsock has also inherited the fallback-specific callback
+	 * functions, switch them back to the original ones.
+	 */
+	if (lsmc->use_fallback) {
+		if (lsmc->clcsk_state_change)
+			new_clcsock->sk->sk_state_change = lsmc->clcsk_state_change;
+		if (lsmc->clcsk_write_space)
+			new_clcsock->sk->sk_write_space = lsmc->clcsk_write_space;
+		if (lsmc->clcsk_error_report)
+			new_clcsock->sk->sk_error_report = lsmc->clcsk_error_report;
+	}
+
+	(*new_smc)->clcsock = new_clcsock;
+out:
+	return rc;
+}
+
+/* add a just created sock to the accept queue of the listen sock as
+ * candidate for a following socket accept call from user space
+ */
+static void smc_accept_enqueue(struct sock *parent, struct sock *sk)
+{
+	struct smc_sock *par = smc_sk(parent);
+
+	sock_hold(sk); /* sock_put in smc_accept_unlink () */
+	spin_lock(&par->accept_q_lock);
+	list_add_tail(&smc_sk(sk)->accept_q, &par->accept_q);
+	spin_unlock(&par->accept_q_lock);
+	sk_acceptq_added(parent);
+}
+
+/* remove a socket from the accept queue of its parental listening socket */
+static void smc_accept_unlink(struct sock *sk)
+{
+	struct smc_sock *par = smc_sk(sk)->listen_smc;
+
+	spin_lock(&par->accept_q_lock);
+	list_del_init(&smc_sk(sk)->accept_q);
+	spin_unlock(&par->accept_q_lock);
+	sk_acceptq_removed(&smc_sk(sk)->listen_smc->sk);
+	sock_put(sk); /* sock_hold in smc_accept_enqueue */
+}
+
+/* remove a sock from the accept queue to bind it to a new socket created
+ * for a socket accept call from user space
+ */
+struct sock *smc_accept_dequeue(struct sock *parent,
+				struct socket *new_sock)
+{
+	struct smc_sock *isk, *n;
+	struct sock *new_sk;
+
+	list_for_each_entry_safe(isk, n, &smc_sk(parent)->accept_q, accept_q) {
+		new_sk = (struct sock *)isk;
+
+		smc_accept_unlink(new_sk);
+		if (new_sk->sk_state == SMC_CLOSED) {
+			new_sk->sk_prot->unhash(new_sk);
+			if (isk->clcsock) {
+				sock_release(isk->clcsock);
+				isk->clcsock = NULL;
+			}
+			sock_put(new_sk); /* final */
+			continue;
+		}
+		if (new_sock) {
+			sock_graft(new_sk, new_sock);
+			new_sock->state = SS_CONNECTED;
+			if (isk->use_fallback) {
+				smc_sk(new_sk)->clcsock->file = new_sock->file;
+				isk->clcsock->file->private_data = isk->clcsock;
+			}
+		}
+		return new_sk;
+	}
+	return NULL;
+}
+
+/* clean up for a created but never accepted sock */
+void smc_close_non_accepted(struct sock *sk)
+{
+	struct smc_sock *smc = smc_sk(sk);
+
+	sock_hold(sk); /* sock_put below */
+	lock_sock(sk);
+	if (!sk->sk_lingertime)
+		/* wait for peer closing */
+		WRITE_ONCE(sk->sk_lingertime, SMC_MAX_STREAM_WAIT_TIMEOUT);
+	__smc_release(smc);
+	release_sock(sk);
+	sock_put(sk); /* sock_hold above */
+	sock_put(sk); /* final sock_put */
+}
+
+static int smcr_serv_conf_first_link(struct smc_sock *smc)
+{
+	struct smc_link *link = smc->conn.lnk;
+	struct smc_llc_qentry *qentry;
+	int rc;
+
+	/* reg the sndbuf if it was vzalloced*/
+	if (smc->conn.sndbuf_desc->is_vm) {
+		if (smcr_link_reg_buf(link, smc->conn.sndbuf_desc))
+			return SMC_CLC_DECL_ERR_REGBUF;
+	}
+
+	/* reg the rmb */
+	if (smcr_link_reg_buf(link, smc->conn.rmb_desc))
+		return SMC_CLC_DECL_ERR_REGBUF;
+
+	/* send CONFIRM LINK request to client over the RoCE fabric */
+	rc = smc_llc_send_confirm_link(link, SMC_LLC_REQ);
+	if (rc < 0)
+		return SMC_CLC_DECL_TIMEOUT_CL;
+
+	/* receive CONFIRM LINK response from client over the RoCE fabric */
+	qentry = smc_llc_wait(link->lgr, link, SMC_LLC_WAIT_TIME,
+			      SMC_LLC_CONFIRM_LINK);
+	if (!qentry) {
+		struct smc_clc_msg_decline dclc;
+
+		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
+		return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_CL : rc;
+	}
+	smc_llc_save_peer_uid(qentry);
+	rc = smc_llc_eval_conf_link(qentry, SMC_LLC_RESP);
+	smc_llc_flow_qentry_del(&link->lgr->llc_flow_lcl);
+	if (rc)
+		return SMC_CLC_DECL_RMBE_EC;
+
+	/* confirm_rkey is implicit on 1st contact */
+	smc->conn.rmb_desc->is_conf_rkey = true;
+
+	smc_llc_link_active(link);
+	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
+
+	mutex_lock(&link->lgr->llc_conf_mutex);
+	/* initial contact - try to establish second link */
+	smc_llc_srv_add_link(link, NULL);
+	mutex_unlock(&link->lgr->llc_conf_mutex);
+	return 0;
+}
+
+/* listen worker: finish */
+static void smc_listen_out(struct smc_sock *new_smc)
+{
+	struct smc_sock *lsmc = new_smc->listen_smc;
+	struct sock *newsmcsk = &new_smc->sk;
+
+	if (tcp_sk(new_smc->clcsock->sk)->syn_smc)
+		atomic_dec(&lsmc->queued_smc_hs);
+
+	if (lsmc->sk.sk_state == SMC_LISTEN) {
+		lock_sock_nested(&lsmc->sk, SINGLE_DEPTH_NESTING);
+		smc_accept_enqueue(&lsmc->sk, newsmcsk);
+		release_sock(&lsmc->sk);
+	} else { /* no longer listening */
+		smc_close_non_accepted(newsmcsk);
+	}
+
+	/* Wake up accept */
+	lsmc->sk.sk_data_ready(&lsmc->sk);
+	sock_put(&lsmc->sk); /* sock_hold in smc_tcp_listen_work */
+}
+
+/* listen worker: finish in state connected */
+static void smc_listen_out_connected(struct smc_sock *new_smc)
+{
+	struct sock *newsmcsk = &new_smc->sk;
+
+	if (newsmcsk->sk_state == SMC_INIT)
+		newsmcsk->sk_state = SMC_ACTIVE;
+
+	smc_listen_out(new_smc);
+}
+
+/* listen worker: finish in error state */
+static void smc_listen_out_err(struct smc_sock *new_smc)
+{
+	struct sock *newsmcsk = &new_smc->sk;
+	struct net *net = sock_net(newsmcsk);
+
+	this_cpu_inc(net->smc.smc_stats->srv_hshake_err_cnt);
+	if (newsmcsk->sk_state == SMC_INIT)
+		sock_put(&new_smc->sk); /* passive closing */
+	newsmcsk->sk_state = SMC_CLOSED;
+
+	smc_listen_out(new_smc);
+}
+
+/* listen worker: decline and fall back if possible */
+static void smc_listen_decline(struct smc_sock *new_smc, int reason_code,
+			       int local_first, u8 version)
+{
+	/* RDMA setup failed, switch back to TCP */
+	smc_conn_abort(new_smc, local_first);
+	if (reason_code < 0 ||
+	    smc_switch_to_fallback(new_smc, reason_code)) {
+		/* error, no fallback possible */
+		smc_listen_out_err(new_smc);
+		return;
+	}
+	if (reason_code && reason_code != SMC_CLC_DECL_PEERDECL) {
+		if (smc_clc_send_decline(new_smc, reason_code, version) < 0) {
+			smc_listen_out_err(new_smc);
+			return;
+		}
+	}
+	smc_listen_out_connected(new_smc);
+}
+
+/* listen worker: version checking */
+static int smc_listen_v2_check(struct smc_sock *new_smc,
+			       struct smc_clc_msg_proposal *pclc,
+			       struct smc_init_info *ini)
+{
+	struct smc_clc_smcd_v2_extension *pclc_smcd_v2_ext;
+	struct smc_clc_v2_extension *pclc_v2_ext;
+	int rc = SMC_CLC_DECL_PEERNOSMC;
+
+	ini->smc_type_v1 = pclc->hdr.typev1;
+	ini->smc_type_v2 = pclc->hdr.typev2;
+	ini->smcd_version = smcd_indicated(ini->smc_type_v1) ? SMC_V1 : 0;
+	ini->smcr_version = smcr_indicated(ini->smc_type_v1) ? SMC_V1 : 0;
+	if (pclc->hdr.version > SMC_V1) {
+		if (smcd_indicated(ini->smc_type_v2))
+			ini->smcd_version |= SMC_V2;
+		if (smcr_indicated(ini->smc_type_v2))
+			ini->smcr_version |= SMC_V2;
+	}
+	if (!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) {
+		rc = SMC_CLC_DECL_PEERNOSMC;
+		goto out;
+	}
+	pclc_v2_ext = smc_get_clc_v2_ext(pclc);
+	if (!pclc_v2_ext) {
+		ini->smcd_version &= ~SMC_V2;
+		ini->smcr_version &= ~SMC_V2;
+		rc = SMC_CLC_DECL_NOV2EXT;
+		goto out;
+	}
+	pclc_smcd_v2_ext = smc_get_clc_smcd_v2_ext(pclc_v2_ext);
+	if (ini->smcd_version & SMC_V2) {
+		if (!smc_ism_is_v2_capable()) {
+			ini->smcd_version &= ~SMC_V2;
+			rc = SMC_CLC_DECL_NOISM2SUPP;
+		} else if (!pclc_smcd_v2_ext) {
+			ini->smcd_version &= ~SMC_V2;
+			rc = SMC_CLC_DECL_NOV2DEXT;
+		} else if (!pclc_v2_ext->hdr.eid_cnt &&
+			   !pclc_v2_ext->hdr.flag.seid) {
+			ini->smcd_version &= ~SMC_V2;
+			rc = SMC_CLC_DECL_NOUEID;
+		}
+	}
+	if (ini->smcr_version & SMC_V2) {
+		if (!pclc_v2_ext->hdr.eid_cnt) {
+			ini->smcr_version &= ~SMC_V2;
+			rc = SMC_CLC_DECL_NOUEID;
+		}
+	}
+
+out:
+	if (!ini->smcd_version && !ini->smcr_version)
+		return rc;
+
+	return 0;
+}
+
+/* listen worker: check prefixes */
+static int smc_listen_prfx_check(struct smc_sock *new_smc,
+				 struct smc_clc_msg_proposal *pclc)
+{
+	struct smc_clc_msg_proposal_prefix *pclc_prfx;
+	struct socket *newclcsock = new_smc->clcsock;
+
+	if (pclc->hdr.typev1 == SMC_TYPE_N)
+		return 0;
+	pclc_prfx = smc_clc_proposal_get_prefix(pclc);
+	if (smc_clc_prfx_match(newclcsock, pclc_prfx))
+		return SMC_CLC_DECL_DIFFPREFIX;
+
+	return 0;
+}
+
+/* listen worker: initialize connection and buffers */
+static int smc_listen_rdma_init(struct smc_sock *new_smc,
+				struct smc_init_info *ini)
+{
+	int rc;
+
+	/* allocate connection / link group */
+	rc = smc_conn_create(new_smc, ini);
+	if (rc)
+		return rc;
+
+	/* create send buffer and rmb */
+	if (smc_buf_create(new_smc, false)) {
+		smc_conn_abort(new_smc, ini->first_contact_local);
+		return SMC_CLC_DECL_MEM;
+	}
+
+	return 0;
+}
+
+/* listen worker: initialize connection and buffers for SMC-D */
+static int smc_listen_ism_init(struct smc_sock *new_smc,
+			       struct smc_init_info *ini)
+{
+	int rc;
+
+	rc = smc_conn_create(new_smc, ini);
+	if (rc)
+		return rc;
+
+	/* Create send and receive buffers */
+	rc = smc_buf_create(new_smc, true);
+	if (rc) {
+		smc_conn_abort(new_smc, ini->first_contact_local);
+		return (rc == -ENOSPC) ? SMC_CLC_DECL_MAX_DMB :
+					 SMC_CLC_DECL_MEM;
+	}
+
+	return 0;
+}
+
+static bool smc_is_already_selected(struct smcd_dev *smcd,
+				    struct smc_init_info *ini,
+				    int matches)
+{
+	int i;
+
+	for (i = 0; i < matches; i++)
+		if (smcd == ini->ism_dev[i])
+			return true;
+
+	return false;
+}
+
+/* check for ISM devices matching proposed ISM devices */
+static void smc_check_ism_v2_match(struct smc_init_info *ini,
+				   u16 proposed_chid, u64 proposed_gid,
+				   unsigned int *matches)
+{
+	struct smcd_dev *smcd;
+
+	list_for_each_entry(smcd, &smcd_dev_list.list, list) {
+		if (smcd->going_away)
+			continue;
+		if (smc_is_already_selected(smcd, ini, *matches))
+			continue;
+		if (smc_ism_get_chid(smcd) == proposed_chid &&
+		    !smc_ism_cantalk(proposed_gid, ISM_RESERVED_VLANID, smcd)) {
+			ini->ism_peer_gid[*matches] = proposed_gid;
+			ini->ism_dev[*matches] = smcd;
+			(*matches)++;
+			break;
+		}
+	}
+}
+
+static void smc_find_ism_store_rc(u32 rc, struct smc_init_info *ini)
+{
+	if (!ini->rc)
+		ini->rc = rc;
+}
+
+static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc,
+					struct smc_clc_msg_proposal *pclc,
+					struct smc_init_info *ini)
+{
+	struct smc_clc_smcd_v2_extension *smcd_v2_ext;
+	struct smc_clc_v2_extension *smc_v2_ext;
+	struct smc_clc_msg_smcd *pclc_smcd;
+	unsigned int matches = 0;
+	u8 smcd_version;
+	u8 *eid = NULL;
+	int i, rc;
+
+	if (!(ini->smcd_version & SMC_V2) || !smcd_indicated(ini->smc_type_v2))
+		goto not_found;
+
+	pclc_smcd = smc_get_clc_msg_smcd(pclc);
+	smc_v2_ext = smc_get_clc_v2_ext(pclc);
+	smcd_v2_ext = smc_get_clc_smcd_v2_ext(smc_v2_ext);
+
+	mutex_lock(&smcd_dev_list.mutex);
+	if (pclc_smcd->ism.chid)
+		/* check for ISM device matching proposed native ISM device */
+		smc_check_ism_v2_match(ini, ntohs(pclc_smcd->ism.chid),
+				       ntohll(pclc_smcd->ism.gid), &matches);
+	for (i = 1; i <= smc_v2_ext->hdr.ism_gid_cnt; i++) {
+		/* check for ISM devices matching proposed non-native ISM
+		 * devices
+		 */
+		smc_check_ism_v2_match(ini,
+				       ntohs(smcd_v2_ext->gidchid[i - 1].chid),
+				       ntohll(smcd_v2_ext->gidchid[i - 1].gid),
+				       &matches);
+	}
+	mutex_unlock(&smcd_dev_list.mutex);
+
+	if (!ini->ism_dev[0]) {
+		smc_find_ism_store_rc(SMC_CLC_DECL_NOSMCD2DEV, ini);
+		goto not_found;
+	}
+
+	smc_ism_get_system_eid(&eid);
+	if (!smc_clc_match_eid(ini->negotiated_eid, smc_v2_ext,
+			       smcd_v2_ext->system_eid, eid))
+		goto not_found;
+
+	/* separate - outside the smcd_dev_list.lock */
+	smcd_version = ini->smcd_version;
+	for (i = 0; i < matches; i++) {
+		ini->smcd_version = SMC_V2;
+		ini->is_smcd = true;
+		ini->ism_selected = i;
+		rc = smc_listen_ism_init(new_smc, ini);
+		if (rc) {
+			smc_find_ism_store_rc(rc, ini);
+			/* try next active ISM device */
+			continue;
+		}
+		return; /* matching and usable V2 ISM device found */
+	}
+	/* no V2 ISM device could be initialized */
+	ini->smcd_version = smcd_version;	/* restore original value */
+	ini->negotiated_eid[0] = 0;
+
+not_found:
+	ini->smcd_version &= ~SMC_V2;
+	ini->ism_dev[0] = NULL;
+	ini->is_smcd = false;
+}
+
+static void smc_find_ism_v1_device_serv(struct smc_sock *new_smc,
+					struct smc_clc_msg_proposal *pclc,
+					struct smc_init_info *ini)
+{
+	struct smc_clc_msg_smcd *pclc_smcd = smc_get_clc_msg_smcd(pclc);
+	int rc = 0;
+
+	/* check if ISM V1 is available */
+	if (!(ini->smcd_version & SMC_V1) || !smcd_indicated(ini->smc_type_v1))
+		goto not_found;
+	ini->is_smcd = true; /* prepare ISM check */
+	ini->ism_peer_gid[0] = ntohll(pclc_smcd->ism.gid);
+	rc = smc_find_ism_device(new_smc, ini);
+	if (rc)
+		goto not_found;
+	ini->ism_selected = 0;
+	rc = smc_listen_ism_init(new_smc, ini);
+	if (!rc)
+		return;		/* V1 ISM device found */
+
+not_found:
+	smc_find_ism_store_rc(rc, ini);
+	ini->smcd_version &= ~SMC_V1;
+	ini->ism_dev[0] = NULL;
+	ini->is_smcd = false;
+}
+
+/* listen worker: register buffers */
+static int smc_listen_rdma_reg(struct smc_sock *new_smc, bool local_first)
+{
+	struct smc_connection *conn = &new_smc->conn;
+
+	if (!local_first) {
+		/* reg sendbufs if they were vzalloced */
+		if (conn->sndbuf_desc->is_vm) {
+			if (smcr_lgr_reg_sndbufs(conn->lnk,
+						 conn->sndbuf_desc))
+				return SMC_CLC_DECL_ERR_REGBUF;
+		}
+		if (smcr_lgr_reg_rmbs(conn->lnk, conn->rmb_desc))
+			return SMC_CLC_DECL_ERR_REGBUF;
+	}
+
+	return 0;
+}
+
+static void smc_find_rdma_v2_device_serv(struct smc_sock *new_smc,
+					 struct smc_clc_msg_proposal *pclc,
+					 struct smc_init_info *ini)
+{
+	struct smc_clc_v2_extension *smc_v2_ext;
+	u8 smcr_version;
+	int rc;
+
+	if (!(ini->smcr_version & SMC_V2) || !smcr_indicated(ini->smc_type_v2))
+		goto not_found;
+
+	smc_v2_ext = smc_get_clc_v2_ext(pclc);
+	if (!smc_clc_match_eid(ini->negotiated_eid, smc_v2_ext, NULL, NULL))
+		goto not_found;
+
+	/* prepare RDMA check */
+	memcpy(ini->peer_systemid, pclc->lcl.id_for_peer, SMC_SYSTEMID_LEN);
+	memcpy(ini->peer_gid, smc_v2_ext->roce, SMC_GID_SIZE);
+	memcpy(ini->peer_mac, pclc->lcl.mac, ETH_ALEN);
+	ini->check_smcrv2 = true;
+	ini->smcrv2.clc_sk = new_smc->clcsock->sk;
+	ini->smcrv2.saddr = new_smc->clcsock->sk->sk_rcv_saddr;
+	ini->smcrv2.daddr = smc_ib_gid_to_ipv4(smc_v2_ext->roce);
+	rc = smc_find_rdma_device(new_smc, ini);
+	if (rc) {
+		smc_find_ism_store_rc(rc, ini);
+		goto not_found;
+	}
+	if (!ini->smcrv2.uses_gateway)
+		memcpy(ini->smcrv2.nexthop_mac, pclc->lcl.mac, ETH_ALEN);
+
+	smcr_version = ini->smcr_version;
+	ini->smcr_version = SMC_V2;
+	rc = smc_listen_rdma_init(new_smc, ini);
+	if (!rc) {
+		rc = smc_listen_rdma_reg(new_smc, ini->first_contact_local);
+		if (rc)
+			smc_conn_abort(new_smc, ini->first_contact_local);
+	}
+	if (!rc)
+		return;
+	ini->smcr_version = smcr_version;
+	smc_find_ism_store_rc(rc, ini);
+
+not_found:
+	ini->smcr_version &= ~SMC_V2;
+	ini->smcrv2.ib_dev_v2 = NULL;
+	ini->check_smcrv2 = false;
+}
+
+static int smc_find_rdma_v1_device_serv(struct smc_sock *new_smc,
+					struct smc_clc_msg_proposal *pclc,
+					struct smc_init_info *ini)
+{
+	int rc;
+
+	if (!(ini->smcr_version & SMC_V1) || !smcr_indicated(ini->smc_type_v1))
+		return SMC_CLC_DECL_NOSMCDEV;
+
+	/* prepare RDMA check */
+	memcpy(ini->peer_systemid, pclc->lcl.id_for_peer, SMC_SYSTEMID_LEN);
+	memcpy(ini->peer_gid, pclc->lcl.gid, SMC_GID_SIZE);
+	memcpy(ini->peer_mac, pclc->lcl.mac, ETH_ALEN);
+	rc = smc_find_rdma_device(new_smc, ini);
+	if (rc) {
+		/* no RDMA device found */
+		return SMC_CLC_DECL_NOSMCDEV;
+	}
+	rc = smc_listen_rdma_init(new_smc, ini);
+	if (rc)
+		return rc;
+	return smc_listen_rdma_reg(new_smc, ini->first_contact_local);
+}
+
+/* determine the local device matching to proposal */
+static int smc_listen_find_device(struct smc_sock *new_smc,
+				  struct smc_clc_msg_proposal *pclc,
+				  struct smc_init_info *ini)
+{
+	int prfx_rc;
+
+	/* check for ISM device matching V2 proposed device */
+	smc_find_ism_v2_device_serv(new_smc, pclc, ini);
+	if (ini->ism_dev[0])
+		return 0;
+
+	/* check for matching IP prefix and subnet length (V1) */
+	prfx_rc = smc_listen_prfx_check(new_smc, pclc);
+	if (prfx_rc)
+		smc_find_ism_store_rc(prfx_rc, ini);
+
+	/* get vlan id from IP device */
+	if (smc_vlan_by_tcpsk(new_smc->clcsock, ini))
+		return ini->rc ?: SMC_CLC_DECL_GETVLANERR;
+
+	/* check for ISM device matching V1 proposed device */
+	if (!prfx_rc)
+		smc_find_ism_v1_device_serv(new_smc, pclc, ini);
+	if (ini->ism_dev[0])
+		return 0;
+
+	if (!smcr_indicated(pclc->hdr.typev1) &&
+	    !smcr_indicated(pclc->hdr.typev2))
+		/* skip RDMA and decline */
+		return ini->rc ?: SMC_CLC_DECL_NOSMCDDEV;
+
+	/* check if RDMA V2 is available */
+	smc_find_rdma_v2_device_serv(new_smc, pclc, ini);
+	if (ini->smcrv2.ib_dev_v2)
+		return 0;
+
+	/* check if RDMA V1 is available */
+	if (!prfx_rc) {
+		int rc;
+
+		rc = smc_find_rdma_v1_device_serv(new_smc, pclc, ini);
+		smc_find_ism_store_rc(rc, ini);
+		return (!rc) ? 0 : ini->rc;
+	}
+	return prfx_rc;
+}
+
+/* listen worker: finish RDMA setup */
+static int smc_listen_rdma_finish(struct smc_sock *new_smc,
+				  struct smc_clc_msg_accept_confirm *cclc,
+				  bool local_first,
+				  struct smc_init_info *ini)
+{
+	struct smc_link *link = new_smc->conn.lnk;
+	int reason_code = 0;
+
+	if (local_first)
+		smc_link_save_peer_info(link, cclc, ini);
+
+	if (smc_rmb_rtoken_handling(&new_smc->conn, link, cclc))
+		return SMC_CLC_DECL_ERR_RTOK;
+
+	if (local_first) {
+		if (smc_ib_ready_link(link))
+			return SMC_CLC_DECL_ERR_RDYLNK;
+		/* QP confirmation over RoCE fabric */
+		smc_llc_flow_initiate(link->lgr, SMC_LLC_FLOW_ADD_LINK);
+		reason_code = smcr_serv_conf_first_link(new_smc);
+		smc_llc_flow_stop(link->lgr, &link->lgr->llc_flow_lcl);
+	}
+	return reason_code;
+}
+
+/* setup for connection of server */
+static void smc_listen_work(struct work_struct *work)
+{
+	struct smc_sock *new_smc = container_of(work, struct smc_sock,
+						smc_listen_work);
+	struct socket *newclcsock = new_smc->clcsock;
+	struct smc_clc_msg_accept_confirm *cclc;
+	struct smc_clc_msg_proposal_area *buf;
+	struct smc_clc_msg_proposal *pclc;
+	struct smc_init_info *ini = NULL;
+	u8 proposal_version = SMC_V1;
+	u8 accept_version;
+	int rc = 0;
+
+	if (new_smc->listen_smc->sk.sk_state != SMC_LISTEN)
+		return smc_listen_out_err(new_smc);
+
+	if (new_smc->use_fallback) {
+		smc_listen_out_connected(new_smc);
+		return;
+	}
+
+	/* check if peer is smc capable */
+	if (!tcp_sk(newclcsock->sk)->syn_smc) {
+		rc = smc_switch_to_fallback(new_smc, SMC_CLC_DECL_PEERNOSMC);
+		if (rc)
+			smc_listen_out_err(new_smc);
+		else
+			smc_listen_out_connected(new_smc);
+		return;
+	}
+
+	/* do inband token exchange -
+	 * wait for and receive SMC Proposal CLC message
+	 */
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf) {
+		rc = SMC_CLC_DECL_MEM;
+		goto out_decl;
+	}
+	pclc = (struct smc_clc_msg_proposal *)buf;
+	rc = smc_clc_wait_msg(new_smc, pclc, sizeof(*buf),
+			      SMC_CLC_PROPOSAL, CLC_WAIT_TIME);
+	if (rc)
+		goto out_decl;
+
+	if (pclc->hdr.version > SMC_V1)
+		proposal_version = SMC_V2;
+
+	/* IPSec connections opt out of SMC optimizations */
+	if (using_ipsec(new_smc)) {
+		rc = SMC_CLC_DECL_IPSEC;
+		goto out_decl;
+	}
+
+	ini = kzalloc(sizeof(*ini), GFP_KERNEL);
+	if (!ini) {
+		rc = SMC_CLC_DECL_MEM;
+		goto out_decl;
+	}
+
+	/* initial version checking */
+	rc = smc_listen_v2_check(new_smc, pclc, ini);
+	if (rc)
+		goto out_decl;
+
+	mutex_lock(&smc_server_lgr_pending);
+	smc_close_init(new_smc);
+	smc_rx_init(new_smc);
+	smc_tx_init(new_smc);
+
+	/* determine ISM or RoCE device used for connection */
+	rc = smc_listen_find_device(new_smc, pclc, ini);
+	if (rc)
+		goto out_unlock;
+
+	/* send SMC Accept CLC message */
+	accept_version = ini->is_smcd ? ini->smcd_version : ini->smcr_version;
+	rc = smc_clc_send_accept(new_smc, ini->first_contact_local,
+				 accept_version, ini->negotiated_eid);
+	if (rc)
+		goto out_unlock;
+
+	/* SMC-D does not need this lock any more */
+	if (ini->is_smcd)
+		mutex_unlock(&smc_server_lgr_pending);
+
+	/* receive SMC Confirm CLC message */
+	memset(buf, 0, sizeof(*buf));
+	cclc = (struct smc_clc_msg_accept_confirm *)buf;
+	rc = smc_clc_wait_msg(new_smc, cclc, sizeof(*buf),
+			      SMC_CLC_CONFIRM, CLC_WAIT_TIME);
+	if (rc) {
+		if (!ini->is_smcd)
+			goto out_unlock;
+		goto out_decl;
+	}
+
+	/* finish worker */
+	if (!ini->is_smcd) {
+		rc = smc_listen_rdma_finish(new_smc, cclc,
+					    ini->first_contact_local, ini);
+		if (rc)
+			goto out_unlock;
+		mutex_unlock(&smc_server_lgr_pending);
+	}
+	smc_conn_save_peer_info(new_smc, cclc);
+	smc_listen_out_connected(new_smc);
+	SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk), ini);
+	goto out_free;
+
+out_unlock:
+	mutex_unlock(&smc_server_lgr_pending);
+out_decl:
+	smc_listen_decline(new_smc, rc, ini ? ini->first_contact_local : 0,
+			   proposal_version);
+out_free:
+	kfree(ini);
+	kfree(buf);
+}
+
+static void smc_tcp_listen_work(struct work_struct *work)
+{
+	struct smc_sock *lsmc = container_of(work, struct smc_sock,
+					     tcp_listen_work);
+	struct sock *lsk = &lsmc->sk;
+	struct smc_sock *new_smc;
+	int rc = 0;
+
+	lock_sock(lsk);
+	while (lsk->sk_state == SMC_LISTEN) {
+		rc = smc_clcsock_accept(lsmc, &new_smc);
+		if (rc) /* clcsock accept queue empty or error */
+			goto out;
+		if (!new_smc)
+			continue;
+
+		if (tcp_sk(new_smc->clcsock->sk)->syn_smc)
+			atomic_inc(&lsmc->queued_smc_hs);
+
+		new_smc->listen_smc = lsmc;
+		new_smc->use_fallback = lsmc->use_fallback;
+		new_smc->fallback_rsn = lsmc->fallback_rsn;
+		sock_hold(lsk); /* sock_put in smc_listen_work */
+		INIT_WORK(&new_smc->smc_listen_work, smc_listen_work);
+		smc_copy_sock_settings_to_smc(new_smc);
+		sock_hold(&new_smc->sk); /* sock_put in passive closing */
+		if (!queue_work(smc_hs_wq, &new_smc->smc_listen_work))
+			sock_put(&new_smc->sk);
+	}
+
+out:
+	release_sock(lsk);
+	sock_put(&lsmc->sk); /* sock_hold in smc_clcsock_data_ready() */
+}
+
+static void smc_clcsock_data_ready(struct sock *listen_clcsock)
+{
+	struct smc_sock *lsmc;
+
+	read_lock_bh(&listen_clcsock->sk_callback_lock);
+	lsmc = smc_clcsock_user_data(listen_clcsock);
+	if (!lsmc)
+		goto out;
+	lsmc->clcsk_data_ready(listen_clcsock);
+	if (lsmc->sk.sk_state == SMC_LISTEN) {
+		sock_hold(&lsmc->sk); /* sock_put in smc_tcp_listen_work() */
+		if (!queue_work(smc_tcp_ls_wq, &lsmc->tcp_listen_work))
+			sock_put(&lsmc->sk);
+	}
+out:
+	read_unlock_bh(&listen_clcsock->sk_callback_lock);
+}
+
+static int smc_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc;
+
+	smc = smc_sk(sk);
+	lock_sock(sk);
+
+	rc = -EINVAL;
+	if ((sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN) ||
+	    smc->connect_nonblock || sock->state != SS_UNCONNECTED)
+		goto out;
+
+	rc = 0;
+	if (sk->sk_state == SMC_LISTEN) {
+		sk->sk_max_ack_backlog = backlog;
+		goto out;
+	}
+	/* some socket options are handled in core, so we could not apply
+	 * them to the clc socket -- copy smc socket options to clc socket
+	 */
+	smc_copy_sock_settings_to_clc(smc);
+	if (!smc->use_fallback)
+		tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+
+	/* save original sk_data_ready function and establish
+	 * smc-specific sk_data_ready function
+	 */
+	write_lock_bh(&smc->clcsock->sk->sk_callback_lock);
+	smc->clcsock->sk->sk_user_data =
+		(void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY);
+	smc_clcsock_replace_cb(&smc->clcsock->sk->sk_data_ready,
+			       smc_clcsock_data_ready, &smc->clcsk_data_ready);
+	write_unlock_bh(&smc->clcsock->sk->sk_callback_lock);
+
+	/* save original ops */
+	smc->ori_af_ops = inet_csk(smc->clcsock->sk)->icsk_af_ops;
+
+	smc->af_ops = *smc->ori_af_ops;
+	smc->af_ops.syn_recv_sock = smc_tcp_syn_recv_sock;
+
+	inet_csk(smc->clcsock->sk)->icsk_af_ops = &smc->af_ops;
+
+	if (smc->limit_smc_hs)
+		tcp_sk(smc->clcsock->sk)->smc_hs_congested = smc_hs_congested;
+
+	rc = kernel_listen(smc->clcsock, backlog);
+	if (rc) {
+		write_lock_bh(&smc->clcsock->sk->sk_callback_lock);
+		smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready,
+				       &smc->clcsk_data_ready);
+		smc->clcsock->sk->sk_user_data = NULL;
+		write_unlock_bh(&smc->clcsock->sk->sk_callback_lock);
+		goto out;
+	}
+	sk->sk_max_ack_backlog = backlog;
+	sk->sk_ack_backlog = 0;
+	sk->sk_state = SMC_LISTEN;
+
+out:
+	release_sock(sk);
+	return rc;
+}
+
+static int smc_accept(struct socket *sock, struct socket *new_sock,
+		      int flags, bool kern)
+{
+	struct sock *sk = sock->sk, *nsk;
+	DECLARE_WAITQUEUE(wait, current);
+	struct smc_sock *lsmc;
+	long timeo;
+	int rc = 0;
+
+	lsmc = smc_sk(sk);
+	sock_hold(sk); /* sock_put below */
+	lock_sock(sk);
+
+	if (lsmc->sk.sk_state != SMC_LISTEN) {
+		rc = -EINVAL;
+		release_sock(sk);
+		goto out;
+	}
+
+	/* Wait for an incoming connection */
+	timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+	add_wait_queue_exclusive(sk_sleep(sk), &wait);
+	while (!(nsk = smc_accept_dequeue(sk, new_sock))) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (!timeo) {
+			rc = -EAGAIN;
+			break;
+		}
+		release_sock(sk);
+		timeo = schedule_timeout(timeo);
+		/* wakeup by sk_data_ready in smc_listen_work() */
+		sched_annotate_sleep();
+		lock_sock(sk);
+		if (signal_pending(current)) {
+			rc = sock_intr_errno(timeo);
+			break;
+		}
+	}
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(sk_sleep(sk), &wait);
+
+	if (!rc)
+		rc = sock_error(nsk);
+	release_sock(sk);
+	if (rc)
+		goto out;
+
+	if (lsmc->sockopt_defer_accept && !(flags & O_NONBLOCK)) {
+		/* wait till data arrives on the socket */
+		timeo = msecs_to_jiffies(lsmc->sockopt_defer_accept *
+								MSEC_PER_SEC);
+		if (smc_sk(nsk)->use_fallback) {
+			struct sock *clcsk = smc_sk(nsk)->clcsock->sk;
+
+			lock_sock(clcsk);
+			if (skb_queue_empty(&clcsk->sk_receive_queue))
+				sk_wait_data(clcsk, &timeo, NULL);
+			release_sock(clcsk);
+		} else if (!atomic_read(&smc_sk(nsk)->conn.bytes_to_rcv)) {
+			lock_sock(nsk);
+			smc_rx_wait(smc_sk(nsk), &timeo, smc_rx_data_available);
+			release_sock(nsk);
+		}
+	}
+
+out:
+	sock_put(sk); /* sock_hold above */
+	return rc;
+}
+
+static int smc_getname(struct socket *sock, struct sockaddr *addr,
+		       int peer)
+{
+	struct smc_sock *smc;
+
+	if (peer && (sock->sk->sk_state != SMC_ACTIVE) &&
+	    (sock->sk->sk_state != SMC_APPCLOSEWAIT1))
+		return -ENOTCONN;
+
+	smc = smc_sk(sock->sk);
+
+	return smc->clcsock->ops->getname(smc->clcsock, addr, peer);
+}
+
+static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc;
+
+	smc = smc_sk(sk);
+	lock_sock(sk);
+
+	/* SMC does not support connect with fastopen */
+	if (msg->msg_flags & MSG_FASTOPEN) {
+		/* not connected yet, fallback */
+		if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
+			rc = smc_switch_to_fallback(smc, SMC_CLC_DECL_OPTUNSUPP);
+			if (rc)
+				goto out;
+		} else {
+			rc = -EINVAL;
+			goto out;
+		}
+	} else if ((sk->sk_state != SMC_ACTIVE) &&
+		   (sk->sk_state != SMC_APPCLOSEWAIT1) &&
+		   (sk->sk_state != SMC_INIT)) {
+		rc = -EPIPE;
+		goto out;
+	}
+
+	if (smc->use_fallback) {
+		rc = smc->clcsock->ops->sendmsg(smc->clcsock, msg, len);
+	} else {
+		rc = smc_tx_sendmsg(smc, msg, len);
+		SMC_STAT_TX_PAYLOAD(smc, len, rc);
+	}
+out:
+	release_sock(sk);
+	return rc;
+}
+
+static int smc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+		       int flags)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc = -ENOTCONN;
+
+	smc = smc_sk(sk);
+	lock_sock(sk);
+	if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) {
+		/* socket was connected before, no more data to read */
+		rc = 0;
+		goto out;
+	}
+	if ((sk->sk_state == SMC_INIT) ||
+	    (sk->sk_state == SMC_LISTEN) ||
+	    (sk->sk_state == SMC_CLOSED))
+		goto out;
+
+	if (sk->sk_state == SMC_PEERFINCLOSEWAIT) {
+		rc = 0;
+		goto out;
+	}
+
+	if (smc->use_fallback) {
+		rc = smc->clcsock->ops->recvmsg(smc->clcsock, msg, len, flags);
+	} else {
+		msg->msg_namelen = 0;
+		rc = smc_rx_recvmsg(smc, msg, NULL, len, flags);
+		SMC_STAT_RX_PAYLOAD(smc, rc, rc);
+	}
+
+out:
+	release_sock(sk);
+	return rc;
+}
+
+static __poll_t smc_accept_poll(struct sock *parent)
+{
+	struct smc_sock *isk = smc_sk(parent);
+	__poll_t mask = 0;
+
+	spin_lock(&isk->accept_q_lock);
+	if (!list_empty(&isk->accept_q))
+		mask = EPOLLIN | EPOLLRDNORM;
+	spin_unlock(&isk->accept_q_lock);
+
+	return mask;
+}
+
+static __poll_t smc_poll(struct file *file, struct socket *sock,
+			     poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	__poll_t mask = 0;
+
+	if (!sk)
+		return EPOLLNVAL;
+
+	smc = smc_sk(sock->sk);
+	if (smc->use_fallback) {
+		/* delegate to CLC child sock */
+		mask = smc->clcsock->ops->poll(file, smc->clcsock, wait);
+		sk->sk_err = smc->clcsock->sk->sk_err;
+	} else {
+		if (sk->sk_state != SMC_CLOSED)
+			sock_poll_wait(file, sock, wait);
+		if (sk->sk_err)
+			mask |= EPOLLERR;
+		if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
+		    (sk->sk_state == SMC_CLOSED))
+			mask |= EPOLLHUP;
+		if (sk->sk_state == SMC_LISTEN) {
+			/* woken up by sk_data_ready in smc_listen_work() */
+			mask |= smc_accept_poll(sk);
+		} else if (smc->use_fallback) { /* as result of connect_work()*/
+			mask |= smc->clcsock->ops->poll(file, smc->clcsock,
+							   wait);
+			sk->sk_err = smc->clcsock->sk->sk_err;
+		} else {
+			if ((sk->sk_state != SMC_INIT &&
+			     atomic_read(&smc->conn.sndbuf_space)) ||
+			    sk->sk_shutdown & SEND_SHUTDOWN) {
+				mask |= EPOLLOUT | EPOLLWRNORM;
+			} else {
+				sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+			}
+			if (atomic_read(&smc->conn.bytes_to_rcv))
+				mask |= EPOLLIN | EPOLLRDNORM;
+			if (sk->sk_shutdown & RCV_SHUTDOWN)
+				mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+			if (sk->sk_state == SMC_APPCLOSEWAIT1)
+				mask |= EPOLLIN;
+			if (smc->conn.urg_state == SMC_URG_VALID)
+				mask |= EPOLLPRI;
+		}
+	}
+
+	return mask;
+}
+
+static int smc_shutdown(struct socket *sock, int how)
+{
+	struct sock *sk = sock->sk;
+	bool do_shutdown = true;
+	struct smc_sock *smc;
+	int rc = -EINVAL;
+	int old_state;
+	int rc1 = 0;
+
+	smc = smc_sk(sk);
+
+	if ((how < SHUT_RD) || (how > SHUT_RDWR))
+		return rc;
+
+	lock_sock(sk);
+
+	if (sock->state == SS_CONNECTING) {
+		if (sk->sk_state == SMC_ACTIVE)
+			sock->state = SS_CONNECTED;
+		else if (sk->sk_state == SMC_PEERCLOSEWAIT1 ||
+			 sk->sk_state == SMC_PEERCLOSEWAIT2 ||
+			 sk->sk_state == SMC_APPCLOSEWAIT1 ||
+			 sk->sk_state == SMC_APPCLOSEWAIT2 ||
+			 sk->sk_state == SMC_APPFINCLOSEWAIT)
+			sock->state = SS_DISCONNECTING;
+	}
+
+	rc = -ENOTCONN;
+	if ((sk->sk_state != SMC_ACTIVE) &&
+	    (sk->sk_state != SMC_PEERCLOSEWAIT1) &&
+	    (sk->sk_state != SMC_PEERCLOSEWAIT2) &&
+	    (sk->sk_state != SMC_APPCLOSEWAIT1) &&
+	    (sk->sk_state != SMC_APPCLOSEWAIT2) &&
+	    (sk->sk_state != SMC_APPFINCLOSEWAIT))
+		goto out;
+	if (smc->use_fallback) {
+		rc = kernel_sock_shutdown(smc->clcsock, how);
+		sk->sk_shutdown = smc->clcsock->sk->sk_shutdown;
+		if (sk->sk_shutdown == SHUTDOWN_MASK) {
+			sk->sk_state = SMC_CLOSED;
+			sk->sk_socket->state = SS_UNCONNECTED;
+			sock_put(sk);
+		}
+		goto out;
+	}
+	switch (how) {
+	case SHUT_RDWR:		/* shutdown in both directions */
+		old_state = sk->sk_state;
+		rc = smc_close_active(smc);
+		if (old_state == SMC_ACTIVE &&
+		    sk->sk_state == SMC_PEERCLOSEWAIT1)
+			do_shutdown = false;
+		break;
+	case SHUT_WR:
+		rc = smc_close_shutdown_write(smc);
+		break;
+	case SHUT_RD:
+		rc = 0;
+		/* nothing more to do because peer is not involved */
+		break;
+	}
+	if (do_shutdown && smc->clcsock)
+		rc1 = kernel_sock_shutdown(smc->clcsock, how);
+	/* map sock_shutdown_cmd constants to sk_shutdown value range */
+	sk->sk_shutdown |= how + 1;
+
+	if (sk->sk_state == SMC_CLOSED)
+		sock->state = SS_UNCONNECTED;
+	else
+		sock->state = SS_DISCONNECTING;
+out:
+	release_sock(sk);
+	return rc ? rc : rc1;
+}
+
+static int __smc_getsockopt(struct socket *sock, int level, int optname,
+			    char __user *optval, int __user *optlen)
+{
+	struct smc_sock *smc;
+	int val, len;
+
+	smc = smc_sk(sock->sk);
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	len = min_t(int, len, sizeof(int));
+
+	if (len < 0)
+		return -EINVAL;
+
+	switch (optname) {
+	case SMC_LIMIT_HS:
+		val = smc->limit_smc_hs;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int __smc_setsockopt(struct socket *sock, int level, int optname,
+			    sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int val, rc;
+
+	smc = smc_sk(sk);
+
+	lock_sock(sk);
+	switch (optname) {
+	case SMC_LIMIT_HS:
+		if (optlen < sizeof(int)) {
+			rc = -EINVAL;
+			break;
+		}
+		if (copy_from_sockptr(&val, optval, sizeof(int))) {
+			rc = -EFAULT;
+			break;
+		}
+
+		smc->limit_smc_hs = !!val;
+		rc = 0;
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+		break;
+	}
+	release_sock(sk);
+
+	return rc;
+}
+
+static int smc_setsockopt(struct socket *sock, int level, int optname,
+			  sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int val, rc;
+
+	if (level == SOL_TCP && optname == TCP_ULP)
+		return -EOPNOTSUPP;
+	else if (level == SOL_SMC)
+		return __smc_setsockopt(sock, level, optname, optval, optlen);
+
+	smc = smc_sk(sk);
+
+	/* generic setsockopts reaching us here always apply to the
+	 * CLC socket
+	 */
+	mutex_lock(&smc->clcsock_release_lock);
+	if (!smc->clcsock) {
+		mutex_unlock(&smc->clcsock_release_lock);
+		return -EBADF;
+	}
+	if (unlikely(!smc->clcsock->ops->setsockopt))
+		rc = -EOPNOTSUPP;
+	else
+		rc = smc->clcsock->ops->setsockopt(smc->clcsock, level, optname,
+						   optval, optlen);
+	if (smc->clcsock->sk->sk_err) {
+		sk->sk_err = smc->clcsock->sk->sk_err;
+		sk_error_report(sk);
+	}
+	mutex_unlock(&smc->clcsock_release_lock);
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+	if (copy_from_sockptr(&val, optval, sizeof(int)))
+		return -EFAULT;
+
+	lock_sock(sk);
+	if (rc || smc->use_fallback)
+		goto out;
+	switch (optname) {
+	case TCP_FASTOPEN:
+	case TCP_FASTOPEN_CONNECT:
+	case TCP_FASTOPEN_KEY:
+	case TCP_FASTOPEN_NO_COOKIE:
+		/* option not supported by SMC */
+		if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
+			rc = smc_switch_to_fallback(smc, SMC_CLC_DECL_OPTUNSUPP);
+		} else {
+			rc = -EINVAL;
+		}
+		break;
+	case TCP_NODELAY:
+		if (sk->sk_state != SMC_INIT &&
+		    sk->sk_state != SMC_LISTEN &&
+		    sk->sk_state != SMC_CLOSED) {
+			if (val) {
+				SMC_STAT_INC(smc, ndly_cnt);
+				smc_tx_pending(&smc->conn);
+				cancel_delayed_work(&smc->conn.tx_work);
+			}
+		}
+		break;
+	case TCP_CORK:
+		if (sk->sk_state != SMC_INIT &&
+		    sk->sk_state != SMC_LISTEN &&
+		    sk->sk_state != SMC_CLOSED) {
+			if (!val) {
+				SMC_STAT_INC(smc, cork_cnt);
+				smc_tx_pending(&smc->conn);
+				cancel_delayed_work(&smc->conn.tx_work);
+			}
+		}
+		break;
+	case TCP_DEFER_ACCEPT:
+		smc->sockopt_defer_accept = val;
+		break;
+	default:
+		break;
+	}
+out:
+	release_sock(sk);
+
+	return rc;
+}
+
+static int smc_getsockopt(struct socket *sock, int level, int optname,
+			  char __user *optval, int __user *optlen)
+{
+	struct smc_sock *smc;
+	int rc;
+
+	if (level == SOL_SMC)
+		return __smc_getsockopt(sock, level, optname, optval, optlen);
+
+	smc = smc_sk(sock->sk);
+	mutex_lock(&smc->clcsock_release_lock);
+	if (!smc->clcsock) {
+		mutex_unlock(&smc->clcsock_release_lock);
+		return -EBADF;
+	}
+	/* socket options apply to the CLC socket */
+	if (unlikely(!smc->clcsock->ops->getsockopt)) {
+		mutex_unlock(&smc->clcsock_release_lock);
+		return -EOPNOTSUPP;
+	}
+	rc = smc->clcsock->ops->getsockopt(smc->clcsock, level, optname,
+					   optval, optlen);
+	mutex_unlock(&smc->clcsock_release_lock);
+	return rc;
+}
+
+static int smc_ioctl(struct socket *sock, unsigned int cmd,
+		     unsigned long arg)
+{
+	union smc_host_cursor cons, urg;
+	struct smc_connection *conn;
+	struct smc_sock *smc;
+	int answ;
+
+	smc = smc_sk(sock->sk);
+	conn = &smc->conn;
+	lock_sock(&smc->sk);
+	if (smc->use_fallback) {
+		if (!smc->clcsock) {
+			release_sock(&smc->sk);
+			return -EBADF;
+		}
+		answ = smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg);
+		release_sock(&smc->sk);
+		return answ;
+	}
+	switch (cmd) {
+	case SIOCINQ: /* same as FIONREAD */
+		if (smc->sk.sk_state == SMC_LISTEN) {
+			release_sock(&smc->sk);
+			return -EINVAL;
+		}
+		if (smc->sk.sk_state == SMC_INIT ||
+		    smc->sk.sk_state == SMC_CLOSED)
+			answ = 0;
+		else
+			answ = atomic_read(&smc->conn.bytes_to_rcv);
+		break;
+	case SIOCOUTQ:
+		/* output queue size (not send + not acked) */
+		if (smc->sk.sk_state == SMC_LISTEN) {
+			release_sock(&smc->sk);
+			return -EINVAL;
+		}
+		if (smc->sk.sk_state == SMC_INIT ||
+		    smc->sk.sk_state == SMC_CLOSED)
+			answ = 0;
+		else
+			answ = smc->conn.sndbuf_desc->len -
+					atomic_read(&smc->conn.sndbuf_space);
+		break;
+	case SIOCOUTQNSD:
+		/* output queue size (not send only) */
+		if (smc->sk.sk_state == SMC_LISTEN) {
+			release_sock(&smc->sk);
+			return -EINVAL;
+		}
+		if (smc->sk.sk_state == SMC_INIT ||
+		    smc->sk.sk_state == SMC_CLOSED)
+			answ = 0;
+		else
+			answ = smc_tx_prepared_sends(&smc->conn);
+		break;
+	case SIOCATMARK:
+		if (smc->sk.sk_state == SMC_LISTEN) {
+			release_sock(&smc->sk);
+			return -EINVAL;
+		}
+		if (smc->sk.sk_state == SMC_INIT ||
+		    smc->sk.sk_state == SMC_CLOSED) {
+			answ = 0;
+		} else {
+			smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
+			smc_curs_copy(&urg, &conn->urg_curs, conn);
+			answ = smc_curs_diff(conn->rmb_desc->len,
+					     &cons, &urg) == 1;
+		}
+		break;
+	default:
+		release_sock(&smc->sk);
+		return -ENOIOCTLCMD;
+	}
+	release_sock(&smc->sk);
+
+	return put_user(answ, (int __user *)arg);
+}
+
+static ssize_t smc_sendpage(struct socket *sock, struct page *page,
+			    int offset, size_t size, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc = -EPIPE;
+
+	smc = smc_sk(sk);
+	lock_sock(sk);
+	if (sk->sk_state != SMC_ACTIVE) {
+		release_sock(sk);
+		goto out;
+	}
+	release_sock(sk);
+	if (smc->use_fallback) {
+		rc = kernel_sendpage(smc->clcsock, page, offset,
+				     size, flags);
+	} else {
+		lock_sock(sk);
+		rc = smc_tx_sendpage(smc, page, offset, size, flags);
+		release_sock(sk);
+		SMC_STAT_INC(smc, sendpage_cnt);
+	}
+
+out:
+	return rc;
+}
+
+/* Map the affected portions of the rmbe into an spd, note the number of bytes
+ * to splice in conn->splice_pending, and press 'go'. Delays consumer cursor
+ * updates till whenever a respective page has been fully processed.
+ * Note that subsequent recv() calls have to wait till all splice() processing
+ * completed.
+ */
+static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
+			       struct pipe_inode_info *pipe, size_t len,
+			       unsigned int flags)
+{
+	struct sock *sk = sock->sk;
+	struct smc_sock *smc;
+	int rc = -ENOTCONN;
+
+	smc = smc_sk(sk);
+	lock_sock(sk);
+	if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) {
+		/* socket was connected before, no more data to read */
+		rc = 0;
+		goto out;
+	}
+	if (sk->sk_state == SMC_INIT ||
+	    sk->sk_state == SMC_LISTEN ||
+	    sk->sk_state == SMC_CLOSED)
+		goto out;
+
+	if (sk->sk_state == SMC_PEERFINCLOSEWAIT) {
+		rc = 0;
+		goto out;
+	}
+
+	if (smc->use_fallback) {
+		rc = smc->clcsock->ops->splice_read(smc->clcsock, ppos,
+						    pipe, len, flags);
+	} else {
+		if (*ppos) {
+			rc = -ESPIPE;
+			goto out;
+		}
+		if (flags & SPLICE_F_NONBLOCK)
+			flags = MSG_DONTWAIT;
+		else
+			flags = 0;
+		SMC_STAT_INC(smc, splice_cnt);
+		rc = smc_rx_recvmsg(smc, NULL, pipe, len, flags);
+	}
+out:
+	release_sock(sk);
+
+	return rc;
+}
+
+/* must look like tcp */
+static const struct proto_ops smc_sock_ops = {
+	.family		= PF_SMC,
+	.owner		= THIS_MODULE,
+	.release	= smc_release,
+	.bind		= smc_bind,
+	.connect	= smc_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= smc_accept,
+	.getname	= smc_getname,
+	.poll		= smc_poll,
+	.ioctl		= smc_ioctl,
+	.listen		= smc_listen,
+	.shutdown	= smc_shutdown,
+	.setsockopt	= smc_setsockopt,
+	.getsockopt	= smc_getsockopt,
+	.sendmsg	= smc_sendmsg,
+	.recvmsg	= smc_recvmsg,
+	.mmap		= sock_no_mmap,
+	.sendpage	= smc_sendpage,
+	.splice_read	= smc_splice_read,
+};
+
+static int __smc_create(struct net *net, struct socket *sock, int protocol,
+			int kern, struct socket *clcsock)
+{
+	int family = (protocol == SMCPROTO_SMC6) ? PF_INET6 : PF_INET;
+	struct smc_sock *smc;
+	struct sock *sk;
+	int rc;
+
+	rc = -ESOCKTNOSUPPORT;
+	if (sock->type != SOCK_STREAM)
+		goto out;
+
+	rc = -EPROTONOSUPPORT;
+	if (protocol != SMCPROTO_SMC && protocol != SMCPROTO_SMC6)
+		goto out;
+
+	rc = -ENOBUFS;
+	sock->ops = &smc_sock_ops;
+	sock->state = SS_UNCONNECTED;
+	sk = smc_sock_alloc(net, sock, protocol);
+	if (!sk)
+		goto out;
+
+	/* create internal TCP socket for CLC handshake and fallback */
+	smc = smc_sk(sk);
+	smc->use_fallback = false; /* assume rdma capability first */
+	smc->fallback_rsn = 0;
+
+	/* default behavior from limit_smc_hs in every net namespace */
+	smc->limit_smc_hs = net->smc.limit_smc_hs;
+
+	rc = 0;
+	if (!clcsock) {
+		rc = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP,
+				      &smc->clcsock);
+		if (rc) {
+			sk_common_release(sk);
+			goto out;
+		}
+	} else {
+		smc->clcsock = clcsock;
+	}
+
+out:
+	return rc;
+}
+
+static int smc_create(struct net *net, struct socket *sock, int protocol,
+		      int kern)
+{
+	return __smc_create(net, sock, protocol, kern, NULL);
+}
+
+static const struct net_proto_family smc_sock_family_ops = {
+	.family	= PF_SMC,
+	.owner	= THIS_MODULE,
+	.create	= smc_create,
+};
+
+static int smc_ulp_init(struct sock *sk)
+{
+	struct socket *tcp = sk->sk_socket;
+	struct net *net = sock_net(sk);
+	struct socket *smcsock;
+	int protocol, ret;
+
+	/* only TCP can be replaced */
+	if (tcp->type != SOCK_STREAM || sk->sk_protocol != IPPROTO_TCP ||
+	    (sk->sk_family != AF_INET && sk->sk_family != AF_INET6))
+		return -ESOCKTNOSUPPORT;
+	/* don't handle wq now */
+	if (tcp->state != SS_UNCONNECTED || !tcp->file || tcp->wq.fasync_list)
+		return -ENOTCONN;
+
+	if (sk->sk_family == AF_INET)
+		protocol = SMCPROTO_SMC;
+	else
+		protocol = SMCPROTO_SMC6;
+
+	smcsock = sock_alloc();
+	if (!smcsock)
+		return -ENFILE;
+
+	smcsock->type = SOCK_STREAM;
+	__module_get(THIS_MODULE); /* tried in __tcp_ulp_find_autoload */
+	ret = __smc_create(net, smcsock, protocol, 1, tcp);
+	if (ret) {
+		sock_release(smcsock); /* module_put() which ops won't be NULL */
+		return ret;
+	}
+
+	/* replace tcp socket to smc */
+	smcsock->file = tcp->file;
+	smcsock->file->private_data = smcsock;
+	smcsock->file->f_inode = SOCK_INODE(smcsock); /* replace inode when sock_close */
+	smcsock->file->f_path.dentry->d_inode = SOCK_INODE(smcsock); /* dput() in __fput */
+	tcp->file = NULL;
+
+	return ret;
+}
+
+static void smc_ulp_clone(const struct request_sock *req, struct sock *newsk,
+			  const gfp_t priority)
+{
+	struct inet_connection_sock *icsk = inet_csk(newsk);
+
+	/* don't inherit ulp ops to child when listen */
+	icsk->icsk_ulp_ops = NULL;
+}
+
+static struct tcp_ulp_ops smc_ulp_ops __read_mostly = {
+	.name		= "smc",
+	.owner		= THIS_MODULE,
+	.init		= smc_ulp_init,
+	.clone		= smc_ulp_clone,
+};
+
+unsigned int smc_net_id;
+
+static __net_init int smc_net_init(struct net *net)
+{
+	int rc;
+
+	rc = smc_sysctl_net_init(net);
+	if (rc)
+		return rc;
+	return smc_pnet_net_init(net);
+}
+
+static void __net_exit smc_net_exit(struct net *net)
+{
+	smc_sysctl_net_exit(net);
+	smc_pnet_net_exit(net);
+}
+
+static __net_init int smc_net_stat_init(struct net *net)
+{
+	return smc_stats_init(net);
+}
+
+static void __net_exit smc_net_stat_exit(struct net *net)
+{
+	smc_stats_exit(net);
+}
+
+static struct pernet_operations smc_net_ops = {
+	.init = smc_net_init,
+	.exit = smc_net_exit,
+	.id   = &smc_net_id,
+	.size = sizeof(struct smc_net),
+};
+
+static struct pernet_operations smc_net_stat_ops = {
+	.init = smc_net_stat_init,
+	.exit = smc_net_stat_exit,
+};
+
+static int __init smc_init(void)
+{
+	int rc;
+
+	rc = register_pernet_subsys(&smc_net_ops);
+	if (rc)
+		return rc;
+
+	rc = register_pernet_subsys(&smc_net_stat_ops);
+	if (rc)
+		goto out_pernet_subsys;
+
+	smc_ism_init();
+	smc_clc_init();
+
+	rc = smc_nl_init();
+	if (rc)
+		goto out_pernet_subsys_stat;
+
+	rc = smc_pnet_init();
+	if (rc)
+		goto out_nl;
+
+	rc = -ENOMEM;
+
+	smc_tcp_ls_wq = alloc_workqueue("smc_tcp_ls_wq", 0, 0);
+	if (!smc_tcp_ls_wq)
+		goto out_pnet;
+
+	smc_hs_wq = alloc_workqueue("smc_hs_wq", 0, 0);
+	if (!smc_hs_wq)
+		goto out_alloc_tcp_ls_wq;
+
+	smc_close_wq = alloc_workqueue("smc_close_wq", 0, 0);
+	if (!smc_close_wq)
+		goto out_alloc_hs_wq;
+
+	rc = smc_core_init();
+	if (rc) {
+		pr_err("%s: smc_core_init fails with %d\n", __func__, rc);
+		goto out_alloc_wqs;
+	}
+
+	rc = smc_llc_init();
+	if (rc) {
+		pr_err("%s: smc_llc_init fails with %d\n", __func__, rc);
+		goto out_core;
+	}
+
+	rc = smc_cdc_init();
+	if (rc) {
+		pr_err("%s: smc_cdc_init fails with %d\n", __func__, rc);
+		goto out_core;
+	}
+
+	rc = proto_register(&smc_proto, 1);
+	if (rc) {
+		pr_err("%s: proto_register(v4) fails with %d\n", __func__, rc);
+		goto out_core;
+	}
+
+	rc = proto_register(&smc_proto6, 1);
+	if (rc) {
+		pr_err("%s: proto_register(v6) fails with %d\n", __func__, rc);
+		goto out_proto;
+	}
+
+	rc = sock_register(&smc_sock_family_ops);
+	if (rc) {
+		pr_err("%s: sock_register fails with %d\n", __func__, rc);
+		goto out_proto6;
+	}
+	INIT_HLIST_HEAD(&smc_v4_hashinfo.ht);
+	INIT_HLIST_HEAD(&smc_v6_hashinfo.ht);
+
+	rc = smc_ib_register_client();
+	if (rc) {
+		pr_err("%s: ib_register fails with %d\n", __func__, rc);
+		goto out_sock;
+	}
+
+	rc = tcp_register_ulp(&smc_ulp_ops);
+	if (rc) {
+		pr_err("%s: tcp_ulp_register fails with %d\n", __func__, rc);
+		goto out_ib;
+	}
+
+	static_branch_enable(&tcp_have_smc);
+	return 0;
+
+out_ib:
+	smc_ib_unregister_client();
+out_sock:
+	sock_unregister(PF_SMC);
+out_proto6:
+	proto_unregister(&smc_proto6);
+out_proto:
+	proto_unregister(&smc_proto);
+out_core:
+	smc_core_exit();
+out_alloc_wqs:
+	destroy_workqueue(smc_close_wq);
+out_alloc_hs_wq:
+	destroy_workqueue(smc_hs_wq);
+out_alloc_tcp_ls_wq:
+	destroy_workqueue(smc_tcp_ls_wq);
+out_pnet:
+	smc_pnet_exit();
+out_nl:
+	smc_nl_exit();
+out_pernet_subsys_stat:
+	unregister_pernet_subsys(&smc_net_stat_ops);
+out_pernet_subsys:
+	unregister_pernet_subsys(&smc_net_ops);
+
+	return rc;
+}
+
+static void __exit smc_exit(void)
+{
+	static_branch_disable(&tcp_have_smc);
+	tcp_unregister_ulp(&smc_ulp_ops);
+	sock_unregister(PF_SMC);
+	smc_core_exit();
+	smc_ib_unregister_client();
+	destroy_workqueue(smc_close_wq);
+	destroy_workqueue(smc_tcp_ls_wq);
+	destroy_workqueue(smc_hs_wq);
+	proto_unregister(&smc_proto6);
+	proto_unregister(&smc_proto);
+	smc_pnet_exit();
+	smc_nl_exit();
+	smc_clc_exit();
+	unregister_pernet_subsys(&smc_net_stat_ops);
+	unregister_pernet_subsys(&smc_net_ops);
+	rcu_barrier();
+}
+
+module_init(smc_init);
+module_exit(smc_exit);
+
+MODULE_AUTHOR("Ursula Braun <ubraun@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("smc socket address family");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_SMC);
+MODULE_ALIAS_TCP_ULP("smc");
+MODULE_ALIAS_GENL_FAMILY(SMC_GENL_FAMILY_NAME);