text: // 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"
  
  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
  						 */
  
  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 *);
  
  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 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);
  	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
  	write_unlock_bh(&h->lock);
  
  	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);
  
  struct proto smc_proto = {
  	.name		= "SMC",
  	.owner		= THIS_MODULE,
  	.keepalive	= smc_set_keepalive,
  	.hash		= smc_hash_sk,
  	.unhash		= smc_unhash_sk,
  	.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,
  	.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_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;
  	}
  }
  
  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);
  		sock_set_flag(sk, SOCK_DEAD);
  		sk->sk_shutdown |= SHUTDOWN_MASK;
  	} else {
  		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 rc = 0;
  
  	if (!sk)
  		goto out;
  
  	sock_hold(sk); /* sock_put below */
  	smc = smc_sk(sk);
  
  	/* cleanup for a dangling non-blocking connect */
  	if (smc->connect_nonblock && sk->sk_state == SMC_INIT)
  		tcp_abort(smc->clcsock->sk, ECONNABORTED);
  	flush_work(&smc->connect_work);
  
  	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);
  
  	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;
  	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);
  
  	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;
  	rc = kernel_bind(smc->clcsock, uaddr, addr_len);
  
  out_rel:
  	release_sock(sk);
  out:
  	return rc;
  }
  
  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_sndbuf = osk->sk_sndbuf;
  	nsk->sk_rcvbuf = osk->sk_rcvbuf;
  	nsk->sk_sndtimeo = osk->sk_sndtimeo;
  	nsk->sk_rcvtimeo = osk->sk_rcvtimeo;
  	nsk->sk_mark = 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;
  }
  
  #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))
  /* 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)
   */
  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 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_rmb()
  	 */
  	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_rmb(&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 */
  	qentry = smc_llc_wait(link->lgr, NULL, 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);
  
  	if (smcr_link_reg_rmb(link, smc->conn.rmb_desc))
  		return SMC_CLC_DECL_ERR_REGRMB;
  
  	/* 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 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 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 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;
  	if (clc->hdr.version > SMC_V1 &&
  	    (clc->hdr.typev2 & SMC_FIRST_CONTACT_MASK)) {
  		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
  			(struct smc_clc_msg_accept_confirm_v2 *)clc;
  		struct smc_clc_first_contact_ext *fce =
  			(struct smc_clc_first_contact_ext *)
  				(((u8 *)clc_v2) + sizeof(*clc_v2));
  
  		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->eid,
  		       SMC_MAX_EID_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 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);
  }
  
  static void smc_link_save_peer_info(struct smc_link *link,
  				    struct smc_clc_msg_accept_confirm *clc)
  {
  	link->peer_qpn = ntoh24(clc->r0.qpn);
  	memcpy(link->peer_gid, clc->r0.lcl.gid, SMC_GID_SIZE);
  	memcpy(link->peer_mac, clc->r0.lcl.mac, sizeof(link->peer_mac));
  	link->peer_psn = ntoh24(clc->r0.psn);
  	link->peer_mtu = clc->r0.qp_mtu;
  }
  
  static void smc_switch_to_fallback(struct smc_sock *smc)
  {
  	smc->use_fallback = true;
  	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;
  	}
  }
  
  /* fall back during connect */
  static int smc_connect_fallback(struct smc_sock *smc, int reason_code)
  {
  	smc_switch_to_fallback(smc);
  	smc->fallback_rsn = reason_code;
  	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)
  {
  	int rc;
  
  	if (reason_code < 0) { /* error, fallback is not possible */
  		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) {
  			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)
  {
  	if (local_first)
  		smc_lgr_cleanup_early(&smc->conn);
  	else
  		smc_conn_free(&smc->conn);
  }
  
  /* 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->ib_dev)
  		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) {
  		if (smc_find_ism_device(smc, ini) ||
  		    smc_connect_ism_vlan_setup(smc, ini)) {
  			if (ini->smc_type_v1 == SMC_TYPE_B)
  				ini->smc_type_v1 = SMC_TYPE_R;
  			else
  				ini->smc_type_v1 = SMC_TYPE_N;
  		} /* else ISM V1 is supported for this connection */
  		if (smc_find_rdma_device(smc, ini)) {
  			if (ini->smc_type_v1 == SMC_TYPE_B)
  				ini->smc_type_v1 = SMC_TYPE_D;
  			else
  				ini->smc_type_v1 = SMC_TYPE_N;
  		} /* else RDMA is supported for this connection */
  	}
  	if (smc_ism_is_v2_capable() && smc_find_ism_v2_device_clnt(smc, ini))
  		ini->smc_type_v2 = SMC_TYPE_N;
  
  	/* if neither ISM nor RDMA are supported, fallback */
  	if (!smcr_indicated(ini->smc_type_v1) &&
  	    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);
  }
  
  /* 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;
  
  	ini->is_smcd = false;
  	ini->ib_lcl = &aclc->r0.lcl;
  	ini->ib_clcqpn = ntoh24(aclc->r0.qpn);
  	ini->first_contact_peer = aclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK;
  
  	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) &&
  			    !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);
  
  	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 {
  		if (smcr_lgr_reg_rmbs(link, smc->conn.rmb_desc)) {
  			reason_code = SMC_CLC_DECL_ERR_REGRMB;
  			goto connect_abort;
  		}
  	}
  	smc_rmb_sync_sg_for_device(&smc->conn);
  
  	reason_code = smc_clc_send_confirm(smc, ini->first_contact_local,
  					   SMC_V1);
  	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->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)
  {
  	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);
  
  	rc = smc_clc_send_confirm(smc, ini->first_contact_local,
  				  aclc->hdr.version);
  	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 &&
  	     !smcr_indicated(ini->smc_type_v1)) ||
  	    (aclc->hdr.typev1 == SMC_TYPE_D &&
  	     ((!smcd_indicated(ini->smc_type_v1) &&
  	       !smcd_indicated(ini->smc_type_v2)) ||
  	      (aclc->hdr.version == SMC_V1 &&
  	       !smcd_indicated(ini->smc_type_v1)) ||
  	      (aclc->hdr.version == SMC_V2 &&
  	       !smcd_indicated(ini->smc_type_v2)))))
  		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;
  	ini->smcd_version |= smc_ism_is_v2_capable() ? SMC_V2 : 0;
  	ini->smc_type_v1 = SMC_TYPE_B;
  	ini->smc_type_v2 = smc_ism_is_v2_capable() ? SMC_TYPE_D : SMC_TYPE_N;
  
  	/* get vlan id from IP device */
  	if (smc_vlan_by_tcpsk(smc->clcsock, ini)) {
  		ini->smcd_version &= ~SMC_V1;
  		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)
  		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;
  	ini->smcd_version = version;
  	if (rc)
  		goto vlan_cleanup;
  
  	/* depending on previous steps, connect using rdma or ism */
  	if (aclc->hdr.typev1 == SMC_TYPE_R)
  		rc = smc_connect_rdma(smc, aclc, ini);
  	else if (aclc->hdr.typev1 == SMC_TYPE_D)
  		rc = smc_connect_ism(smc, aclc, ini);
  	if (rc)
  		goto vlan_cleanup;
  
  	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 | TCP_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 (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 (sk->sk_state) {
  	default:
  		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;
  
  	sock_hold(&smc->sk); /* sock put in passive closing */
  	if (smc->use_fallback)
  		goto out;
  	if (flags & O_NONBLOCK) {
  		if (queue_work(smc_hs_wq, &smc->connect_work))
  			smc->connect_nonblock = 1;
  		rc = -EINPROGRESS;
  	} else {
  		rc = __smc_connect(smc);
  		if (rc < 0)
  			goto out;
  		else
  			rc = 0; /* success cases including fallback */
  	}
  
  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;
  		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;
  	(*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);
  			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 */
  		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;
  
  	if (smcr_link_reg_rmb(link, smc->conn.rmb_desc))
  		return SMC_CLC_DECL_ERR_REGRMB;
  
  	/* 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);
  
  	/* initial contact - try to establish second link */
  	smc_llc_srv_add_link(link);
  	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 (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;
  
  	sk_refcnt_debug_inc(newsmcsk);
  	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;
  
  	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) { /* error, no fallback possible */
  		smc_listen_out_err(new_smc);
  		return;
  	}
  	smc_switch_to_fallback(new_smc);
  	new_smc->fallback_rsn = reason_code;
  	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 = ini->smc_type_v1 != SMC_TYPE_N ? SMC_V1 : 0;
  	if (pclc->hdr.version > SMC_V1)
  		ini->smcd_version |=
  				ini->smc_type_v2 != SMC_TYPE_N ? SMC_V2 : 0;
  	if (!(ini->smcd_version & SMC_V2)) {
  		rc = SMC_CLC_DECL_PEERNOSMC;
  		goto out;
  	}
  	if (!smc_ism_is_v2_capable()) {
  		ini->smcd_version &= ~SMC_V2;
  		rc = SMC_CLC_DECL_NOISM2SUPP;
  		goto out;
  	}
  	pclc_v2_ext = smc_get_clc_v2_ext(pclc);
  	if (!pclc_v2_ext) {
  		ini->smcd_version &= ~SMC_V2;
  		rc = SMC_CLC_DECL_NOV2EXT;
  		goto out;
  	}
  	pclc_smcd_v2_ext = smc_get_clc_smcd_v2_ext(pclc_v2_ext);
  	if (!pclc_smcd_v2_ext) {
  		ini->smcd_version &= ~SMC_V2;
  		rc = SMC_CLC_DECL_NOV2DEXT;
  	}
  
  out:
  	if (!ini->smcd_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))
  		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);
  	if (!smcd_v2_ext ||
  	    !smc_v2_ext->hdr.flag.seid) { /* no system EID support for SMCD */
  		smc_find_ism_store_rc(SMC_CLC_DECL_NOSEID, ini);
  		goto not_found;
  	}
  
  	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_ism_get_system_eid(ini->ism_dev[0], &eid);
  		if (memcmp(eid, smcd_v2_ext->system_eid, SMC_MAX_EID_LEN))
  			goto not_found;
  	} else {
  		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 */
  
  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->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) {
  		if (smcr_lgr_reg_rmbs(conn->lnk, conn->rmb_desc))
  			return SMC_CLC_DECL_ERR_REGRMB;
  	}
  	smc_rmb_sync_sg_for_device(&new_smc->conn);
  
  	return 0;
  }
  
  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 (!smcr_indicated(ini->smc_type_v1))
  		return SMC_CLC_DECL_NOSMCDEV;
  
  	/* prepare RDMA check */
  	ini->ib_lcl = &pclc->lcl;
  	rc = smc_find_rdma_device(new_smc, ini);
  	if (rc) {
  		/* no RDMA device found */
  		if (ini->smc_type_v1 == SMC_TYPE_B)
  			/* neither ISM nor RDMA device found */
  			rc = SMC_CLC_DECL_NOSMCDEV;
  		return rc;
  	}
  	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 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;
  
  	if (!(ini->smcd_version & SMC_V1))
  		return ini->rc ?: SMC_CLC_DECL_NOSMCD2DEV;
  
  	/* check for matching IP prefix and subnet length */
  	rc = smc_listen_prfx_check(new_smc, pclc);
  	if (rc)
  		return ini->rc ?: rc;
  
  	/* 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 */
  	smc_find_ism_v1_device_serv(new_smc, pclc, ini);
  	if (ini->ism_dev[0])
  		return 0;
  
  	if (pclc->hdr.typev1 == SMC_TYPE_D)
  		/* skip RDMA and decline */
  		return ini->rc ?: SMC_CLC_DECL_NOSMCDDEV;
  
  	/* check if RDMA is available */
  	rc = smc_find_rdma_v1_device_serv(new_smc, pclc, ini);
  	smc_find_ism_store_rc(rc, ini);
  
  	return (!rc) ? 0 : ini->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_link *link = new_smc->conn.lnk;
  	int reason_code = 0;
  
  	if (local_first)
  		smc_link_save_peer_info(link, cclc);
  
  	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);
  	u8 version = smc_ism_is_v2_capable() ? SMC_V2 : SMC_V1;
  	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;
  	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) {
  		smc_switch_to_fallback(new_smc);
  		new_smc->fallback_rsn = SMC_CLC_DECL_PEERNOSMC;
  		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;
  	version = pclc->hdr.version == SMC_V1 ? SMC_V1 : version;
  
  	/* 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 */
  	rc = smc_clc_send_accept(new_smc, ini->first_contact_local,
  				 ini->smcd_version == SMC_V2 ? SMC_V2 : SMC_V1);
  	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);
  		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);
  	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,
  			   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;
  
  		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);
  		new_smc->sk.sk_sndbuf = lsmc->sk.sk_sndbuf;
  		new_smc->sk.sk_rcvbuf = lsmc->sk.sk_rcvbuf;
  		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;
  
  	lsmc = (struct smc_sock *)
  	       ((uintptr_t)listen_clcsock->sk_user_data & ~SK_USER_DATA_NOCOPY);
  	if (!lsmc)
  		return;
  	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_hs_wq, &lsmc->tcp_listen_work))
  			sock_put(&lsmc->sk);
  	}
  }
  
  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)
  		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
  	 */
  	smc->clcsk_data_ready = smc->clcsock->sk->sk_data_ready;
  	smc->clcsock->sk->sk_data_ready = smc_clcsock_data_ready;
  	smc->clcsock->sk->sk_user_data =
  		(void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY);
  	rc = kernel_listen(smc->clcsock, backlog);
  	if (rc)
  		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 = -EPIPE;
  
  	smc = smc_sk(sk);
  	lock_sock(sk);
  	if ((sk->sk_state != SMC_ACTIVE) &&
  	    (sk->sk_state != SMC_APPCLOSEWAIT1) &&
  	    (sk->sk_state != SMC_INIT))
  		goto out;
  
  	if (msg->msg_flags & MSG_FASTOPEN) {
  		if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
  			smc_switch_to_fallback(smc);
  			smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
  		} else {
  			rc = -EINVAL;
  			goto out;
  		}
  	}
  
  	if (smc->use_fallback)
  		rc = smc->clcsock->ops->sendmsg(smc->clcsock, msg, len);
  	else
  		rc = smc_tx_sendmsg(smc, msg, len);
  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);
  	}
  
  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;
  	struct smc_sock *smc;
  	int rc = -EINVAL;
  	int rc1 = 0;
  
  	smc = smc_sk(sk);
  
  	if ((how < SHUT_RD) || (how > SHUT_RDWR))
  		return rc;
  
  	lock_sock(sk);
  
  	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;
  		goto out;
  	}
  	switch (how) {
  	case SHUT_RDWR:		/* shutdown in both directions */
  		rc = smc_close_active(smc);
  		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 (smc->clcsock)
  		rc1 = kernel_sock_shutdown(smc->clcsock, how);
  	/* map sock_shutdown_cmd constants to sk_shutdown value range */
  	sk->sk_shutdown |= how + 1;
  
  out:
  	release_sock(sk);
  	return rc ? rc : rc1;
  }
  
  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;
  
  	smc = smc_sk(sk);
  
  	/* generic setsockopts reaching us here always apply to the
  	 * CLC socket
  	 */
  	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->sk_error_report(sk);
  	}
  
  	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) {
  			smc_switch_to_fallback(smc);
  			smc->fallback_rsn = 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)
  				mod_delayed_work(smc->conn.lgr->tx_wq,
  						 &smc->conn.tx_work, 0);
  		}
  		break;
  	case TCP_CORK:
  		if (sk->sk_state != SMC_INIT &&
  		    sk->sk_state != SMC_LISTEN &&
  		    sk->sk_state != SMC_CLOSED) {
  			if (!val)
  				mod_delayed_work(smc->conn.lgr->tx_wq,
  						 &smc->conn.tx_work, 0);
  		}
  		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;
  
  	smc = smc_sk(sock->sk);
  	/* socket options apply to the CLC socket */
  	if (unlikely(!smc->clcsock->ops->getsockopt))
  		return -EOPNOTSUPP;
  	return smc->clcsock->ops->getsockopt(smc->clcsock, level, optname,
  					     optval, optlen);
  }
  
  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
  		rc = sock_no_sendpage(sock, page, offset, size, flags);
  
  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;
  		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)
  {
  	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;
  	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;
  	rc = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP,
  			      &smc->clcsock);
  	if (rc) {
  		sk_common_release(sk);
  		goto out;
  	}
  	smc->sk.sk_sndbuf = max(smc->clcsock->sk->sk_sndbuf, SMC_BUF_MIN_SIZE);
  	smc->sk.sk_rcvbuf = max(smc->clcsock->sk->sk_rcvbuf, SMC_BUF_MIN_SIZE);
  
  out:
  	return rc;
  }
  
  static const struct net_proto_family smc_sock_family_ops = {
  	.family	= PF_SMC,
  	.owner	= THIS_MODULE,
  	.create	= smc_create,
  };
  
  unsigned int smc_net_id;
  
  static __net_init int smc_net_init(struct net *net)
  {
  	return smc_pnet_net_init(net);
  }
  
  static void __net_exit smc_net_exit(struct net *net)
  {
  	smc_pnet_net_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 int __init smc_init(void)
  {
  	int rc;
  
  	rc = register_pernet_subsys(&smc_net_ops);
  	if (rc)
  		return rc;
  
  	smc_ism_init();
  	smc_clc_init();
  
  	rc = smc_nl_init();
  	if (rc)
  		goto out_pernet_subsys;
  
  	rc = smc_pnet_init();
  	if (rc)
  		goto out_nl;
  
  	rc = -ENOMEM;
  	smc_hs_wq = alloc_workqueue("smc_hs_wq", 0, 0);
  	if (!smc_hs_wq)
  		goto out_pnet;
  
  	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;
  	}
  
  	static_branch_enable(&tcp_have_smc);
  	return 0;
  
  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_pnet:
  	smc_pnet_exit();
  out_nl:
  	smc_nl_exit();
  out_pernet_subsys:
  	unregister_pernet_subsys(&smc_net_ops);
  
  	return rc;
  }
  
  static void __exit smc_exit(void)
  {
  	static_branch_disable(&tcp_have_smc);
  	sock_unregister(PF_SMC);
  	smc_core_exit();
  	smc_ib_unregister_client();
  	destroy_workqueue(smc_close_wq);
  	destroy_workqueue(smc_hs_wq);
  	proto_unregister(&smc_proto6);
  	proto_unregister(&smc_proto);
  	smc_pnet_exit();
  	smc_nl_exit();
  	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);
  