// 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);