// 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 <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_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
                                                 */

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 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);
        }

        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;

        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); /* 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 a new rmb, send confirm_rkey msg to register with peer */
static int smc_reg_rmb(struct smc_link *link, struct smc_buf_desc *rmb_desc,
                       bool conf_rkey)
{
        if (!rmb_desc->wr_reg) {
                /* register memory region for new rmb */
                if (smc_wr_reg_send(link, rmb_desc->mr_rx[SMC_SINGLE_LINK])) {
                        rmb_desc->regerr = 1;
                        return -EFAULT;
                }
                rmb_desc->wr_reg = 1;
        }
        if (!conf_rkey)
                return 0;
        /* exchange confirm_rkey msg with peer */
        if (smc_llc_do_confirm_rkey(link, rmb_desc)) {
                rmb_desc->regerr = 1;
                return -EFAULT;
        }
        return 0;
}

static int smc_clnt_conf_first_link(struct smc_sock *smc)
{
        struct net *net = sock_net(smc->clcsock->sk);
        struct smc_link_group *lgr = smc->conn.lgr;
        struct smc_link *link;
        int rest;
        int rc;

        link = &lgr->lnk[SMC_SINGLE_LINK];
        /* receive CONFIRM LINK request from server over RoCE fabric */
        rest = wait_for_completion_interruptible_timeout(
                &link->llc_confirm,
                SMC_LLC_WAIT_FIRST_TIME);
        if (rest <= 0) {
                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;
        }

        if (link->llc_confirm_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 (smc_reg_rmb(link, smc->conn.rmb_desc, false))
                return SMC_CLC_DECL_ERR_REGRMB;

        /* 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;

        /* receive ADD LINK request from server over RoCE fabric */
        rest = wait_for_completion_interruptible_timeout(&link->llc_add,
                                                         SMC_LLC_WAIT_TIME);
        if (rest <= 0) {
                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_AL : rc;
        }

        /* send add link reject message, only one link supported for now */
        rc = smc_llc_send_add_link(link,
                                   link->smcibdev->mac[link->ibport - 1],
                                   link->gid, SMC_LLC_RESP);
        if (rc < 0)
                return SMC_CLC_DECL_TIMEOUT_AL;

        smc_llc_link_active(link, net->ipv4.sysctl_tcp_keepalive_time);

        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->rmbe_size);

        smc->conn.peer_rmbe_idx = clc->rmbe_idx;
        smc->conn.local_tx_ctrl.token = ntohl(clc->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->dmbe_size);

        smc->conn.peer_rmbe_idx = clc->dmbe_idx;
        smc->conn.peer_token = clc->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);
}

static void smc_link_save_peer_info(struct smc_link *link,
                                    struct smc_clc_msg_accept_confirm *clc)
{
        link->peer_qpn = ntoh24(clc->qpn);
        memcpy(link->peer_gid, clc->lcl.gid, SMC_GID_SIZE);
        memcpy(link->peer_mac, clc->lcl.mac, sizeof(link->peer_mac));
        link->peer_psn = ntoh24(clc->psn);
        link->peer_mtu = clc->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;
        }
}

/* 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)
{
        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);
                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);
}

/* abort connecting */
static int smc_connect_abort(struct smc_sock *smc, int reason_code,
                             int local_contact)
{
        if (local_contact == SMC_FIRST_CONTACT)
                smc_lgr_forget(smc->conn.lgr);
        if (smc->conn.lgr->is_smcd)
                /* there is only one lgr role for SMC-D; use server lock */
                mutex_unlock(&smc_server_lgr_pending);
        else
                mutex_unlock(&smc_client_lgr_pending);

        smc_conn_free(&smc->conn);
        smc->connect_nonblock = 0;
        return reason_code;
}

/* 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)
                return SMC_CLC_DECL_NOSMCDDEV;
        return 0;
}

/* 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, ini->vlan_id))
                return SMC_CLC_DECL_ISMVLANERR;
        return 0;
}

/* 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, bool is_smcd,
                                        struct smc_init_info *ini)
{
        if (!is_smcd)
                return 0;
        if (ini->vlan_id && smc_ism_put_vlan(ini->ism_dev, ini->vlan_id))
                return SMC_CLC_DECL_CNFERR;
        return 0;
}

/* CLC handshake during connect */
static int smc_connect_clc(struct smc_sock *smc, int smc_type,
                           struct smc_clc_msg_accept_confirm *aclc,
                           struct smc_init_info *ini)
{
        int rc = 0;

        /* do inband token exchange */
        rc = smc_clc_send_proposal(smc, smc_type, ini);
        if (rc)
                return rc;
        /* receive SMC Accept CLC message */
        return smc_clc_wait_msg(smc, aclc, sizeof(*aclc), 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)
{
        struct smc_link *link;
        int reason_code = 0;

        ini->is_smcd = false;
        ini->ib_lcl = &aclc->lcl;
        ini->ib_clcqpn = ntoh24(aclc->qpn);
        ini->srv_first_contact = aclc->hdr.flag;

        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;
        }
        link = &smc->conn.lgr->lnk[SMC_SINGLE_LINK];

        smc_conn_save_peer_info(smc, aclc);

        /* create send buffer and rmb */
        if (smc_buf_create(smc, false))
                return smc_connect_abort(smc, SMC_CLC_DECL_MEM,
                                         ini->cln_first_contact);

        if (ini->cln_first_contact == SMC_FIRST_CONTACT)
                smc_link_save_peer_info(link, aclc);

        if (smc_rmb_rtoken_handling(&smc->conn, aclc))
                return smc_connect_abort(smc, SMC_CLC_DECL_ERR_RTOK,
                                         ini->cln_first_contact);

        smc_close_init(smc);
        smc_rx_init(smc);

        if (ini->cln_first_contact == SMC_FIRST_CONTACT) {
                if (smc_ib_ready_link(link))
                        return smc_connect_abort(smc, SMC_CLC_DECL_ERR_RDYLNK,
                                                 ini->cln_first_contact);
        } else {
                if (smc_reg_rmb(link, smc->conn.rmb_desc, true))
                        return smc_connect_abort(smc, SMC_CLC_DECL_ERR_REGRMB,
                                                 ini->cln_first_contact);
        }
        smc_rmb_sync_sg_for_device(&smc->conn);

        reason_code = smc_clc_send_confirm(smc);
        if (reason_code)
                return smc_connect_abort(smc, reason_code,
                                         ini->cln_first_contact);

        smc_tx_init(smc);

        if (ini->cln_first_contact == SMC_FIRST_CONTACT) {
                /* QP confirmation over RoCE fabric */
                reason_code = smc_clnt_conf_first_link(smc);
                if (reason_code)
                        return smc_connect_abort(smc, reason_code,
                                                 ini->cln_first_contact);
        }
        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;
}

/* 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->ism_gid = aclc->gid;
        ini->srv_first_contact = aclc->hdr.flag;

        /* 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 */
        if (smc_buf_create(smc, true))
                return smc_connect_abort(smc, SMC_CLC_DECL_MEM,
                                         ini->cln_first_contact);

        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);
        if (rc)
                return smc_connect_abort(smc, rc, ini->cln_first_contact);
        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;
}

/* perform steps before actually connecting */
static int __smc_connect(struct smc_sock *smc)
{
        bool ism_supported = false, rdma_supported = false;
        struct smc_clc_msg_accept_confirm aclc;
        struct smc_init_info ini = {0};
        int smc_type;
        int rc = 0;

        sock_hold(&smc->sk); /* sock put in passive closing */

        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-R optimizations */
        if (using_ipsec(smc))
                return smc_connect_decline_fallback(smc, SMC_CLC_DECL_IPSEC);

        /* get vlan id from IP device */
        if (smc_vlan_by_tcpsk(smc->clcsock, &ini))
                return smc_connect_decline_fallback(smc,
                                                    SMC_CLC_DECL_GETVLANERR);

        /* check if there is an ism device available */
        if (!smc_find_ism_device(smc, &ini) &&
            !smc_connect_ism_vlan_setup(smc, &ini)) {
                /* ISM is supported for this connection */
                ism_supported = true;
                smc_type = SMC_TYPE_D;
        }

        /* check if there is a rdma device available */
        if (!smc_find_rdma_device(smc, &ini)) {
                /* RDMA is supported for this connection */
                rdma_supported = true;
                if (ism_supported)
                        smc_type = SMC_TYPE_B; /* both */
                else
                        smc_type = SMC_TYPE_R; /* only RDMA */
        }

        /* if neither ISM nor RDMA are supported, fallback */
        if (!rdma_supported && !ism_supported)
                return smc_connect_decline_fallback(smc, SMC_CLC_DECL_NOSMCDEV);

        /* perform CLC handshake */
        rc = smc_connect_clc(smc, smc_type, &aclc, &ini);
        if (rc) {
                smc_connect_ism_vlan_cleanup(smc, ism_supported, &ini);
                return smc_connect_decline_fallback(smc, rc);
        }

        /* depending on previous steps, connect using rdma or ism */
        if (rdma_supported && aclc.hdr.path == SMC_TYPE_R)
                rc = smc_connect_rdma(smc, &aclc, &ini);
        else if (ism_supported && aclc.hdr.path == SMC_TYPE_D)
                rc = smc_connect_ism(smc, &aclc, &ini);
        else
                rc = SMC_CLC_DECL_MODEUNSUPP;
        if (rc) {
                smc_connect_ism_vlan_cleanup(smc, ism_supported, &ini);
                return smc_connect_decline_fallback(smc, rc);
        }

        smc_connect_ism_vlan_cleanup(smc, ism_supported, &ini);
        return 0;
}

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);
                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:
                rc = 0;
                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 (flags & O_NONBLOCK) {
                if (schedule_work(&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, 0);
        mutex_unlock(&lsmc->clcsock_release_lock);
        lock_sock(lsk);
        if  (rc < 0)
                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_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);

        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); /* final sock_put */
}

static int smc_serv_conf_first_link(struct smc_sock *smc)
{
        struct net *net = sock_net(smc->clcsock->sk);
        struct smc_link_group *lgr = smc->conn.lgr;
        struct smc_link *link;
        int rest;
        int rc;

        link = &lgr->lnk[SMC_SINGLE_LINK];

        if (smc_reg_rmb(link, smc->conn.rmb_desc, false))
                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 */

        rest = wait_for_completion_interruptible_timeout(
                &link->llc_confirm_resp,
                SMC_LLC_WAIT_FIRST_TIME);
        if (rest <= 0) {
                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;
        }

        if (link->llc_confirm_resp_rc)
                return SMC_CLC_DECL_RMBE_EC;

        /* send ADD LINK request to client over the RoCE fabric */
        rc = smc_llc_send_add_link(link,
                                   link->smcibdev->mac[link->ibport - 1],
                                   link->gid, SMC_LLC_REQ);
        if (rc < 0)
                return SMC_CLC_DECL_TIMEOUT_AL;

        /* receive ADD LINK response from client over the RoCE fabric */
        rest = wait_for_completion_interruptible_timeout(&link->llc_add_resp,
                                                         SMC_LLC_WAIT_TIME);
        if (rest <= 0) {
                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_AL : rc;
        }

        smc_llc_link_active(link, net->ipv4.sysctl_tcp_keepalive_time);

        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_conn_free(&new_smc->conn);

        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_contact)
{
        /* RDMA setup failed, switch back to TCP */
        if (local_contact == SMC_FIRST_CONTACT)
                smc_lgr_forget(new_smc->conn.lgr);
        if (reason_code < 0) { /* error, no fallback possible */
                smc_listen_out_err(new_smc);
                return;
        }
        smc_conn_free(&new_smc->conn);
        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) < 0) {
                        smc_listen_out_err(new_smc);
                        return;
                }
        }
        smc_listen_out_connected(new_smc);
}

/* 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;

        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_clc_msg_proposal *pclc,
                               struct smc_init_info *ini)
{
        struct smc_clc_msg_smcd *pclc_smcd;
        int rc;

        pclc_smcd = smc_get_clc_msg_smcd(pclc);
        ini->ism_gid = pclc_smcd->gid;
        rc = smc_conn_create(new_smc, ini);
        if (rc)
                return rc;

        /* Check if peer can be reached via ISM device */
        if (smc_ism_cantalk(new_smc->conn.lgr->peer_gid,
                            new_smc->conn.lgr->vlan_id,
                            new_smc->conn.lgr->smcd)) {
                if (ini->cln_first_contact == SMC_FIRST_CONTACT)
                        smc_lgr_forget(new_smc->conn.lgr);
                smc_conn_free(&new_smc->conn);
                return SMC_CLC_DECL_SMCDNOTALK;
        }

        /* Create send and receive buffers */
        if (smc_buf_create(new_smc, true)) {
                if (ini->cln_first_contact == SMC_FIRST_CONTACT)
                        smc_lgr_forget(new_smc->conn.lgr);
                smc_conn_free(&new_smc->conn);
                return SMC_CLC_DECL_MEM;
        }

        return 0;
}

/* listen worker: register buffers */
static int smc_listen_rdma_reg(struct smc_sock *new_smc, int local_contact)
{
        struct smc_link *link = &new_smc->conn.lgr->lnk[SMC_SINGLE_LINK];

        if (local_contact != SMC_FIRST_CONTACT) {
                if (smc_reg_rmb(link, new_smc->conn.rmb_desc, true))
                        return SMC_CLC_DECL_ERR_REGRMB;
        }
        smc_rmb_sync_sg_for_device(&new_smc->conn);

        return 0;
}

/* listen worker: finish RDMA setup */
static int smc_listen_rdma_finish(struct smc_sock *new_smc,
                                  struct smc_clc_msg_accept_confirm *cclc,
                                  int local_contact)
{
        struct smc_link *link = &new_smc->conn.lgr->lnk[SMC_SINGLE_LINK];
        int reason_code = 0;

        if (local_contact == SMC_FIRST_CONTACT)
                smc_link_save_peer_info(link, cclc);

        if (smc_rmb_rtoken_handling(&new_smc->conn, cclc)) {
                reason_code = SMC_CLC_DECL_ERR_RTOK;
                goto decline;
        }

        if (local_contact == SMC_FIRST_CONTACT) {
                if (smc_ib_ready_link(link)) {
                        reason_code = SMC_CLC_DECL_ERR_RDYLNK;
                        goto decline;
                }
                /* QP confirmation over RoCE fabric */
                reason_code = smc_serv_conf_first_link(new_smc);
                if (reason_code)
                        goto decline;
        }
        return 0;

decline:
        smc_listen_decline(new_smc, reason_code, local_contact);
        return reason_code;
}

/* setup for RDMA 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 *pclc;
        struct smc_init_info ini = {0};
        bool ism_supported = false;
        u8 buf[SMC_CLC_MAX_LEN];
        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
         */
        pclc = (struct smc_clc_msg_proposal *)&buf;
        rc = smc_clc_wait_msg(new_smc, pclc, SMC_CLC_MAX_LEN,
                              SMC_CLC_PROPOSAL, CLC_WAIT_TIME);
        if (rc)
                goto out_decl;

        /* IPSec connections opt out of SMC-R optimizations */
        if (using_ipsec(new_smc)) {
                rc = SMC_CLC_DECL_IPSEC;
                goto out_decl;
        }

        /* check for matching IP prefix and subnet length */
        rc = smc_listen_prfx_check(new_smc, pclc);
        if (rc)
                goto out_decl;

        /* get vlan id from IP device */
        if (smc_vlan_by_tcpsk(new_smc->clcsock, &ini)) {
                rc = SMC_CLC_DECL_GETVLANERR;
                goto out_decl;
        }

        mutex_lock(&smc_server_lgr_pending);
        smc_close_init(new_smc);
        smc_rx_init(new_smc);
        smc_tx_init(new_smc);

        /* check if ISM is available */
        if (pclc->hdr.path == SMC_TYPE_D || pclc->hdr.path == SMC_TYPE_B) {
                ini.is_smcd = true; /* prepare ISM check */
                rc = smc_find_ism_device(new_smc, &ini);
                if (!rc)
                        rc = smc_listen_ism_init(new_smc, pclc, &ini);
                if (!rc)
                        ism_supported = true;
                else if (pclc->hdr.path == SMC_TYPE_D)
                        goto out_unlock; /* skip RDMA and decline */
        }

        /* check if RDMA is available */
        if (!ism_supported) { /* SMC_TYPE_R or SMC_TYPE_B */
                /* prepare RDMA check */
                memset(&ini, 0, sizeof(ini));
                ini.is_smcd = false;
                ini.ib_lcl = &pclc->lcl;
                rc = smc_find_rdma_device(new_smc, &ini);
                if (rc) {
                        /* no RDMA device found */
                        if (pclc->hdr.path == SMC_TYPE_B)
                                /* neither ISM nor RDMA device found */
                                rc = SMC_CLC_DECL_NOSMCDEV;
                        goto out_unlock;
                }
                rc = smc_listen_rdma_init(new_smc, &ini);
                if (rc)
                        goto out_unlock;
                rc = smc_listen_rdma_reg(new_smc, ini.cln_first_contact);
                if (rc)
                        goto out_unlock;
        }

        /* send SMC Accept CLC message */
        rc = smc_clc_send_accept(new_smc, ini.cln_first_contact);
        if (rc)
                goto out_unlock;

        /* SMC-D does not need this lock any more */
        if (ism_supported)
                mutex_unlock(&smc_server_lgr_pending);

        /* receive SMC Confirm CLC message */
        rc = smc_clc_wait_msg(new_smc, &cclc, sizeof(cclc),
                              SMC_CLC_CONFIRM, CLC_WAIT_TIME);
        if (rc) {
                if (!ism_supported)
                        goto out_unlock;
                goto out_decl;
        }

        /* finish worker */
        if (!ism_supported) {
                rc = smc_listen_rdma_finish(new_smc, &cclc,
                                            ini.cln_first_contact);
                mutex_unlock(&smc_server_lgr_pending);
                if (rc)
                        return;
        }
        smc_conn_save_peer_info(new_smc, &cclc);
        smc_listen_out_connected(new_smc);
        return;

out_unlock:
        mutex_unlock(&smc_server_lgr_pending);
out_decl:
        smc_listen_decline(new_smc, rc, ini.cln_first_contact);
}

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)
                        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 (!schedule_work(&new_smc->smc_listen_work))
                        sock_put(&new_smc->sk);
        }

out:
        release_sock(lsk);
        sock_put(&lsmc->sk); /* sock_hold in smc_listen */
}

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;

        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;
        sock_hold(sk); /* sock_hold in tcp_listen_worker */
        if (!schedule_work(&smc->tcp_listen_work))
                sock_put(sk);

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,
                          char __user *optval, unsigned int optlen)
{
        struct sock *sk = sock->sk;
        struct smc_sock *smc;
        int val, rc;

        smc = smc_sk(sk);

        /* generic setsockopts reaching us here always apply to the
         * CLC socket
         */
        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 (rc)
                return rc;

        if (optlen < sizeof(int))
                return -EINVAL;
        if (get_user(val, (int __user *)optval))
                return -EFAULT;

        lock_sock(sk);
        switch (optname) {
        case TCP_ULP:
        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_switch_to_fallback(smc);
                        smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
                } else {
                        if (!smc->use_fallback)
                                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->use_fallback)
                                mod_delayed_work(system_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 && !smc->use_fallback)
                                mod_delayed_work(system_wq, &smc->conn.tx_work,
                                                 0);
                }
                break;
        case TCP_DEFER_ACCEPT:
                smc->sockopt_defer_accept = val;
                break;
        default:
                break;
        }
        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 */
        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;

        rc = smc_pnet_init();
        if (rc)
                goto out_pernet_subsys;

        rc = smc_llc_init();
        if (rc) {
                pr_err("%s: smc_llc_init fails with %d\n", __func__, rc);
                goto out_pnet;
        }

        rc = smc_cdc_init();
        if (rc) {
                pr_err("%s: smc_cdc_init fails with %d\n", __func__, rc);
                goto out_pnet;
        }

        rc = proto_register(&smc_proto, 1);
        if (rc) {
                pr_err("%s: proto_register(v4) fails with %d\n", __func__, rc);
                goto out_pnet;
        }

        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_pnet:
        smc_pnet_exit();
out_pernet_subsys:
        unregister_pernet_subsys(&smc_net_ops);

        return rc;
}

static void __exit smc_exit(void)
{
        smc_core_exit();
        static_branch_disable(&tcp_have_smc);
        smc_ib_unregister_client();
        sock_unregister(PF_SMC);
        proto_unregister(&smc_proto6);
        proto_unregister(&smc_proto);
        smc_pnet_exit();
        unregister_pernet_subsys(&smc_net_ops);
}

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);