// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  IB infrastructure:
 *  Establish SMC-R as an Infiniband Client to be notified about added and
 *  removed IB devices of type RDMA.
 *  Determine device and port characteristics for these IB devices.
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include <linux/random.h>
#include <linux/workqueue.h>
#include <linux/scatterlist.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#include <linux/inetdevice.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_cache.h>

#include "smc_pnet.h"
#include "smc_ib.h"
#include "smc_core.h"
#include "smc_wr.h"
#include "smc.h"
#include "smc_netlink.h"

#define SMC_MAX_CQE 32766       /* max. # of completion queue elements */

#define SMC_QP_MIN_RNR_TIMER            5
#define SMC_QP_TIMEOUT                  15 /* 4096 * 2 ** timeout usec */
#define SMC_QP_RETRY_CNT                        7 /* 7: infinite */
#define SMC_QP_RNR_RETRY                        7 /* 7: infinite */

struct smc_ib_devices smc_ib_devices = {        /* smc-registered ib devices */
        .mutex = __MUTEX_INITIALIZER(smc_ib_devices.mutex),
        .list = LIST_HEAD_INIT(smc_ib_devices.list),
};

u8 local_systemid[SMC_SYSTEMID_LEN];            /* unique system identifier */

static int smc_ib_modify_qp_init(struct smc_link *lnk)
{
        struct ib_qp_attr qp_attr;

        memset(&qp_attr, 0, sizeof(qp_attr));
        qp_attr.qp_state = IB_QPS_INIT;
        qp_attr.pkey_index = 0;
        qp_attr.port_num = lnk->ibport;
        qp_attr.qp_access_flags = IB_ACCESS_LOCAL_WRITE
                                | IB_ACCESS_REMOTE_WRITE;
        return ib_modify_qp(lnk->roce_qp, &qp_attr,
                            IB_QP_STATE | IB_QP_PKEY_INDEX |
                            IB_QP_ACCESS_FLAGS | IB_QP_PORT);
}

static int smc_ib_modify_qp_rtr(struct smc_link *lnk)
{
        enum ib_qp_attr_mask qp_attr_mask =
                IB_QP_STATE | IB_QP_AV | IB_QP_PATH_MTU | IB_QP_DEST_QPN |
                IB_QP_RQ_PSN | IB_QP_MAX_DEST_RD_ATOMIC | IB_QP_MIN_RNR_TIMER;
        struct ib_qp_attr qp_attr;
        u8 hop_lim = 1;

        memset(&qp_attr, 0, sizeof(qp_attr));
        qp_attr.qp_state = IB_QPS_RTR;
        qp_attr.path_mtu = min(lnk->path_mtu, lnk->peer_mtu);
        qp_attr.ah_attr.type = RDMA_AH_ATTR_TYPE_ROCE;
        rdma_ah_set_port_num(&qp_attr.ah_attr, lnk->ibport);
        if (lnk->lgr->smc_version == SMC_V2 && lnk->lgr->uses_gateway)
                hop_lim = IPV6_DEFAULT_HOPLIMIT;
        rdma_ah_set_grh(&qp_attr.ah_attr, NULL, 0, lnk->sgid_index, hop_lim, 0);
        rdma_ah_set_dgid_raw(&qp_attr.ah_attr, lnk->peer_gid);
        if (lnk->lgr->smc_version == SMC_V2 && lnk->lgr->uses_gateway)
                memcpy(&qp_attr.ah_attr.roce.dmac, lnk->lgr->nexthop_mac,
                       sizeof(lnk->lgr->nexthop_mac));
        else
                memcpy(&qp_attr.ah_attr.roce.dmac, lnk->peer_mac,
                       sizeof(lnk->peer_mac));
        qp_attr.dest_qp_num = lnk->peer_qpn;
        qp_attr.rq_psn = lnk->peer_psn; /* starting receive packet seq # */
        qp_attr.max_dest_rd_atomic = 1; /* max # of resources for incoming
                                         * requests
                                         */
        qp_attr.min_rnr_timer = SMC_QP_MIN_RNR_TIMER;

        return ib_modify_qp(lnk->roce_qp, &qp_attr, qp_attr_mask);
}

int smc_ib_modify_qp_rts(struct smc_link *lnk)
{
        struct ib_qp_attr qp_attr;

        memset(&qp_attr, 0, sizeof(qp_attr));
        qp_attr.qp_state = IB_QPS_RTS;
        qp_attr.timeout = SMC_QP_TIMEOUT;       /* local ack timeout */
        qp_attr.retry_cnt = SMC_QP_RETRY_CNT;   /* retry count */
        qp_attr.rnr_retry = SMC_QP_RNR_RETRY;   /* RNR retries, 7=infinite */
        qp_attr.sq_psn = lnk->psn_initial;      /* starting send packet seq # */
        qp_attr.max_rd_atomic = 1;      /* # of outstanding RDMA reads and
                                         * atomic ops allowed
                                         */
        return ib_modify_qp(lnk->roce_qp, &qp_attr,
                            IB_QP_STATE | IB_QP_TIMEOUT | IB_QP_RETRY_CNT |
                            IB_QP_SQ_PSN | IB_QP_RNR_RETRY |
                            IB_QP_MAX_QP_RD_ATOMIC);
}

int smc_ib_modify_qp_error(struct smc_link *lnk)
{
        struct ib_qp_attr qp_attr;

        memset(&qp_attr, 0, sizeof(qp_attr));
        qp_attr.qp_state = IB_QPS_ERR;
        return ib_modify_qp(lnk->roce_qp, &qp_attr, IB_QP_STATE);
}

int smc_ib_ready_link(struct smc_link *lnk)
{
        struct smc_link_group *lgr = smc_get_lgr(lnk);
        int rc = 0;

        rc = smc_ib_modify_qp_init(lnk);
        if (rc)
                goto out;

        rc = smc_ib_modify_qp_rtr(lnk);
        if (rc)
                goto out;
        smc_wr_remember_qp_attr(lnk);
        rc = ib_req_notify_cq(lnk->smcibdev->roce_cq_recv,
                              IB_CQ_SOLICITED_MASK);
        if (rc)
                goto out;
        rc = smc_wr_rx_post_init(lnk);
        if (rc)
                goto out;
        smc_wr_remember_qp_attr(lnk);

        if (lgr->role == SMC_SERV) {
                rc = smc_ib_modify_qp_rts(lnk);
                if (rc)
                        goto out;
                smc_wr_remember_qp_attr(lnk);
        }
out:
        return rc;
}

static int smc_ib_fill_mac(struct smc_ib_device *smcibdev, u8 ibport)
{
        const struct ib_gid_attr *attr;
        int rc;

        attr = rdma_get_gid_attr(smcibdev->ibdev, ibport, 0);
        if (IS_ERR(attr))
                return -ENODEV;

        rc = rdma_read_gid_l2_fields(attr, NULL, smcibdev->mac[ibport - 1]);
        rdma_put_gid_attr(attr);
        return rc;
}

/* Create an identifier unique for this instance of SMC-R.
 * The MAC-address of the first active registered IB device
 * plus a random 2-byte number is used to create this identifier.
 * This name is delivered to the peer during connection initialization.
 */
static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
                                                u8 ibport)
{
        memcpy(&local_systemid[2], &smcibdev->mac[ibport - 1],
               sizeof(smcibdev->mac[ibport - 1]));
}

bool smc_ib_is_valid_local_systemid(void)
{
        return !is_zero_ether_addr(&local_systemid[2]);
}

static void smc_ib_init_local_systemid(void)
{
        get_random_bytes(&local_systemid[0], 2);
}

bool smc_ib_port_active(struct smc_ib_device *smcibdev, u8 ibport)
{
        return smcibdev->pattr[ibport - 1].state == IB_PORT_ACTIVE;
}

int smc_ib_find_route(struct net *net, __be32 saddr, __be32 daddr,
                      u8 nexthop_mac[], u8 *uses_gateway)
{
        struct neighbour *neigh = NULL;
        struct rtable *rt = NULL;
        struct flowi4 fl4 = {
                .saddr = saddr,
                .daddr = daddr
        };

        if (daddr == cpu_to_be32(INADDR_NONE))
                goto out;
        rt = ip_route_output_flow(net, &fl4, NULL);
        if (IS_ERR(rt))
                goto out;
        if (rt->rt_uses_gateway && rt->rt_gw_family != AF_INET)
                goto out_rt;
        neigh = dst_neigh_lookup(&rt->dst, &fl4.daddr);
        if (!neigh)
                goto out_rt;
        memcpy(nexthop_mac, neigh->ha, ETH_ALEN);
        *uses_gateway = rt->rt_uses_gateway;
        neigh_release(neigh);
        ip_rt_put(rt);
        return 0;

out_rt:
        ip_rt_put(rt);
out:
        return -ENOENT;
}

static int smc_ib_determine_gid_rcu(const struct net_device *ndev,
                                    const struct ib_gid_attr *attr,
                                    u8 gid[], u8 *sgid_index,
                                    struct smc_init_info_smcrv2 *smcrv2)
{
        if (!smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE) {
                if (gid)
                        memcpy(gid, &attr->gid, SMC_GID_SIZE);
                if (sgid_index)
                        *sgid_index = attr->index;
                return 0;
        }
        if (smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE_UDP_ENCAP &&
            smc_ib_gid_to_ipv4((u8 *)&attr->gid) != cpu_to_be32(INADDR_NONE)) {
                struct in_device *in_dev = __in_dev_get_rcu(ndev);
                struct net *net = dev_net(ndev);
                const struct in_ifaddr *ifa;
                bool subnet_match = false;

                if (!in_dev)
                        goto out;
                in_dev_for_each_ifa_rcu(ifa, in_dev) {
                        if (!inet_ifa_match(smcrv2->saddr, ifa))
                                continue;
                        subnet_match = true;
                        break;
                }
                if (!subnet_match)
                        goto out;
                if (smcrv2->daddr && smc_ib_find_route(net, smcrv2->saddr,
                                                       smcrv2->daddr,
                                                       smcrv2->nexthop_mac,
                                                       &smcrv2->uses_gateway))
                        goto out;

                if (gid)
                        memcpy(gid, &attr->gid, SMC_GID_SIZE);
                if (sgid_index)
                        *sgid_index = attr->index;
                return 0;
        }
out:
        return -ENODEV;
}

/* determine the gid for an ib-device port and vlan id */
int smc_ib_determine_gid(struct smc_ib_device *smcibdev, u8 ibport,
                         unsigned short vlan_id, u8 gid[], u8 *sgid_index,
                         struct smc_init_info_smcrv2 *smcrv2)
{
        const struct ib_gid_attr *attr;
        const struct net_device *ndev;
        int i;

        for (i = 0; i < smcibdev->pattr[ibport - 1].gid_tbl_len; i++) {
                attr = rdma_get_gid_attr(smcibdev->ibdev, ibport, i);
                if (IS_ERR(attr))
                        continue;

                rcu_read_lock();
                ndev = rdma_read_gid_attr_ndev_rcu(attr);
                if (!IS_ERR(ndev) &&
                    ((!vlan_id && !is_vlan_dev(ndev)) ||
                     (vlan_id && is_vlan_dev(ndev) &&
                      vlan_dev_vlan_id(ndev) == vlan_id))) {
                        if (!smc_ib_determine_gid_rcu(ndev, attr, gid,
                                                      sgid_index, smcrv2)) {
                                rcu_read_unlock();
                                rdma_put_gid_attr(attr);
                                return 0;
                        }
                }
                rcu_read_unlock();
                rdma_put_gid_attr(attr);
        }
        return -ENODEV;
}

/* check if gid is still defined on smcibdev */
static bool smc_ib_check_link_gid(u8 gid[SMC_GID_SIZE], bool smcrv2,
                                  struct smc_ib_device *smcibdev, u8 ibport)
{
        const struct ib_gid_attr *attr;
        bool rc = false;
        int i;

        for (i = 0; !rc && i < smcibdev->pattr[ibport - 1].gid_tbl_len; i++) {
                attr = rdma_get_gid_attr(smcibdev->ibdev, ibport, i);
                if (IS_ERR(attr))
                        continue;

                rcu_read_lock();
                if ((!smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE) ||
                    (smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE_UDP_ENCAP &&
                     !(ipv6_addr_type((const struct in6_addr *)&attr->gid)
                                     & IPV6_ADDR_LINKLOCAL)))
                        if (!memcmp(gid, &attr->gid, SMC_GID_SIZE))
                                rc = true;
                rcu_read_unlock();
                rdma_put_gid_attr(attr);
        }
        return rc;
}

/* check all links if the gid is still defined on smcibdev */
static void smc_ib_gid_check(struct smc_ib_device *smcibdev, u8 ibport)
{
        struct smc_link_group *lgr;
        int i;

        spin_lock_bh(&smc_lgr_list.lock);
        list_for_each_entry(lgr, &smc_lgr_list.list, list) {
                if (strncmp(smcibdev->pnetid[ibport - 1], lgr->pnet_id,
                            SMC_MAX_PNETID_LEN))
                        continue; /* lgr is not affected */
                if (list_empty(&lgr->list))
                        continue;
                for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
                        if (lgr->lnk[i].state == SMC_LNK_UNUSED ||
                            lgr->lnk[i].smcibdev != smcibdev)
                                continue;
                        if (!smc_ib_check_link_gid(lgr->lnk[i].gid,
                                                   lgr->smc_version == SMC_V2,
                                                   smcibdev, ibport))
                                smcr_port_err(smcibdev, ibport);
                }
        }
        spin_unlock_bh(&smc_lgr_list.lock);
}

static int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport)
{
        int rc;

        memset(&smcibdev->pattr[ibport - 1], 0,
               sizeof(smcibdev->pattr[ibport - 1]));
        rc = ib_query_port(smcibdev->ibdev, ibport,
                           &smcibdev->pattr[ibport - 1]);
        if (rc)
                goto out;
        /* the SMC protocol requires specification of the RoCE MAC address */
        rc = smc_ib_fill_mac(smcibdev, ibport);
        if (rc)
                goto out;
        if (!smc_ib_is_valid_local_systemid() &&
            smc_ib_port_active(smcibdev, ibport))
                /* create unique system identifier */
                smc_ib_define_local_systemid(smcibdev, ibport);
out:
        return rc;
}

/* process context wrapper for might_sleep smc_ib_remember_port_attr */
static void smc_ib_port_event_work(struct work_struct *work)
{
        struct smc_ib_device *smcibdev = container_of(
                work, struct smc_ib_device, port_event_work);
        u8 port_idx;

        for_each_set_bit(port_idx, &smcibdev->port_event_mask, SMC_MAX_PORTS) {
                smc_ib_remember_port_attr(smcibdev, port_idx + 1);
                clear_bit(port_idx, &smcibdev->port_event_mask);
                if (!smc_ib_port_active(smcibdev, port_idx + 1)) {
                        set_bit(port_idx, smcibdev->ports_going_away);
                        smcr_port_err(smcibdev, port_idx + 1);
                } else {
                        clear_bit(port_idx, smcibdev->ports_going_away);
                        smcr_port_add(smcibdev, port_idx + 1);
                        smc_ib_gid_check(smcibdev, port_idx + 1);
                }
        }
}

/* can be called in IRQ context */
static void smc_ib_global_event_handler(struct ib_event_handler *handler,
                                        struct ib_event *ibevent)
{
        struct smc_ib_device *smcibdev;
        bool schedule = false;
        u8 port_idx;

        smcibdev = container_of(handler, struct smc_ib_device, event_handler);

        switch (ibevent->event) {
        case IB_EVENT_DEVICE_FATAL:
                /* terminate all ports on device */
                for (port_idx = 0; port_idx < SMC_MAX_PORTS; port_idx++) {
                        set_bit(port_idx, &smcibdev->port_event_mask);
                        if (!test_and_set_bit(port_idx,
                                              smcibdev->ports_going_away))
                                schedule = true;
                }
                if (schedule)
                        schedule_work(&smcibdev->port_event_work);
                break;
        case IB_EVENT_PORT_ACTIVE:
                port_idx = ibevent->element.port_num - 1;
                if (port_idx >= SMC_MAX_PORTS)
                        break;
                set_bit(port_idx, &smcibdev->port_event_mask);
                if (test_and_clear_bit(port_idx, smcibdev->ports_going_away))
                        schedule_work(&smcibdev->port_event_work);
                break;
        case IB_EVENT_PORT_ERR:
                port_idx = ibevent->element.port_num - 1;
                if (port_idx >= SMC_MAX_PORTS)
                        break;
                set_bit(port_idx, &smcibdev->port_event_mask);
                if (!test_and_set_bit(port_idx, smcibdev->ports_going_away))
                        schedule_work(&smcibdev->port_event_work);
                break;
        case IB_EVENT_GID_CHANGE:
                port_idx = ibevent->element.port_num - 1;
                if (port_idx >= SMC_MAX_PORTS)
                        break;
                set_bit(port_idx, &smcibdev->port_event_mask);
                schedule_work(&smcibdev->port_event_work);
                break;
        default:
                break;
        }
}

void smc_ib_dealloc_protection_domain(struct smc_link *lnk)
{
        if (lnk->roce_pd)
                ib_dealloc_pd(lnk->roce_pd);
        lnk->roce_pd = NULL;
}

int smc_ib_create_protection_domain(struct smc_link *lnk)
{
        int rc;

        lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev, 0);
        rc = PTR_ERR_OR_ZERO(lnk->roce_pd);
        if (IS_ERR(lnk->roce_pd))
                lnk->roce_pd = NULL;
        return rc;
}

static bool smcr_diag_is_dev_critical(struct smc_lgr_list *smc_lgr,
                                      struct smc_ib_device *smcibdev)
{
        struct smc_link_group *lgr;
        bool rc = false;
        int i;

        spin_lock_bh(&smc_lgr->lock);
        list_for_each_entry(lgr, &smc_lgr->list, list) {
                if (lgr->is_smcd)
                        continue;
                for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
                        if (lgr->lnk[i].state == SMC_LNK_UNUSED ||
                            lgr->lnk[i].smcibdev != smcibdev)
                                continue;
                        if (lgr->type == SMC_LGR_SINGLE ||
                            lgr->type == SMC_LGR_ASYMMETRIC_LOCAL) {
                                rc = true;
                                goto out;
                        }
                }
        }
out:
        spin_unlock_bh(&smc_lgr->lock);
        return rc;
}

static int smc_nl_handle_dev_port(struct sk_buff *skb,
                                  struct ib_device *ibdev,
                                  struct smc_ib_device *smcibdev,
                                  int port)
{
        char smc_pnet[SMC_MAX_PNETID_LEN + 1];
        struct nlattr *port_attrs;
        unsigned char port_state;
        int lnk_count = 0;

        port_attrs = nla_nest_start(skb, SMC_NLA_DEV_PORT + port);
        if (!port_attrs)
                goto errout;

        if (nla_put_u8(skb, SMC_NLA_DEV_PORT_PNET_USR,
                       smcibdev->pnetid_by_user[port]))
                goto errattr;
        memcpy(smc_pnet, &smcibdev->pnetid[port], SMC_MAX_PNETID_LEN);
        smc_pnet[SMC_MAX_PNETID_LEN] = 0;
        if (nla_put_string(skb, SMC_NLA_DEV_PORT_PNETID, smc_pnet))
                goto errattr;
        if (nla_put_u32(skb, SMC_NLA_DEV_PORT_NETDEV,
                        smcibdev->ndev_ifidx[port]))
                goto errattr;
        if (nla_put_u8(skb, SMC_NLA_DEV_PORT_VALID, 1))
                goto errattr;
        port_state = smc_ib_port_active(smcibdev, port + 1);
        if (nla_put_u8(skb, SMC_NLA_DEV_PORT_STATE, port_state))
                goto errattr;
        lnk_count = atomic_read(&smcibdev->lnk_cnt_by_port[port]);
        if (nla_put_u32(skb, SMC_NLA_DEV_PORT_LNK_CNT, lnk_count))
                goto errattr;
        nla_nest_end(skb, port_attrs);
        return 0;
errattr:
        nla_nest_cancel(skb, port_attrs);
errout:
        return -EMSGSIZE;
}

static bool smc_nl_handle_pci_values(const struct smc_pci_dev *smc_pci_dev,
                                     struct sk_buff *skb)
{
        if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev->pci_fid))
                return false;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev->pci_pchid))
                return false;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_VENDOR, smc_pci_dev->pci_vendor))
                return false;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_DEVICE, smc_pci_dev->pci_device))
                return false;
        if (nla_put_string(skb, SMC_NLA_DEV_PCI_ID, smc_pci_dev->pci_id))
                return false;
        return true;
}

static int smc_nl_handle_smcr_dev(struct smc_ib_device *smcibdev,
                                  struct sk_buff *skb,
                                  struct netlink_callback *cb)
{
        char smc_ibname[IB_DEVICE_NAME_MAX];
        struct smc_pci_dev smc_pci_dev;
        struct pci_dev *pci_dev;
        unsigned char is_crit;
        struct nlattr *attrs;
        void *nlh;
        int i;

        nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
                          &smc_gen_nl_family, NLM_F_MULTI,
                          SMC_NETLINK_GET_DEV_SMCR);
        if (!nlh)
                goto errmsg;
        attrs = nla_nest_start(skb, SMC_GEN_DEV_SMCR);
        if (!attrs)
                goto errout;
        is_crit = smcr_diag_is_dev_critical(&smc_lgr_list, smcibdev);
        if (nla_put_u8(skb, SMC_NLA_DEV_IS_CRIT, is_crit))
                goto errattr;
        if (smcibdev->ibdev->dev.parent) {
                memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));
                pci_dev = to_pci_dev(smcibdev->ibdev->dev.parent);
                smc_set_pci_values(pci_dev, &smc_pci_dev);
                if (!smc_nl_handle_pci_values(&smc_pci_dev, skb))
                        goto errattr;
        }
        snprintf(smc_ibname, sizeof(smc_ibname), "%s", smcibdev->ibdev->name);
        if (nla_put_string(skb, SMC_NLA_DEV_IB_NAME, smc_ibname))
                goto errattr;
        for (i = 1; i <= SMC_MAX_PORTS; i++) {
                if (!rdma_is_port_valid(smcibdev->ibdev, i))
                        continue;
                if (smc_nl_handle_dev_port(skb, smcibdev->ibdev,
                                           smcibdev, i - 1))
                        goto errattr;
        }

        nla_nest_end(skb, attrs);
        genlmsg_end(skb, nlh);
        return 0;

errattr:
        nla_nest_cancel(skb, attrs);
errout:
        genlmsg_cancel(skb, nlh);
errmsg:
        return -EMSGSIZE;
}

static void smc_nl_prep_smcr_dev(struct smc_ib_devices *dev_list,
                                 struct sk_buff *skb,
                                 struct netlink_callback *cb)
{
        struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
        struct smc_ib_device *smcibdev;
        int snum = cb_ctx->pos[0];
        int num = 0;

        mutex_lock(&dev_list->mutex);
        list_for_each_entry(smcibdev, &dev_list->list, list) {
                if (num < snum)
                        goto next;
                if (smc_nl_handle_smcr_dev(smcibdev, skb, cb))
                        goto errout;
next:
                num++;
        }
errout:
        mutex_unlock(&dev_list->mutex);
        cb_ctx->pos[0] = num;
}

int smcr_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb)
{
        smc_nl_prep_smcr_dev(&smc_ib_devices, skb, cb);
        return skb->len;
}

static void smc_ib_qp_event_handler(struct ib_event *ibevent, void *priv)
{
        struct smc_link *lnk = (struct smc_link *)priv;
        struct smc_ib_device *smcibdev = lnk->smcibdev;
        u8 port_idx;

        switch (ibevent->event) {
        case IB_EVENT_QP_FATAL:
        case IB_EVENT_QP_ACCESS_ERR:
                port_idx = ibevent->element.qp->port - 1;
                if (port_idx >= SMC_MAX_PORTS)
                        break;
                set_bit(port_idx, &smcibdev->port_event_mask);
                if (!test_and_set_bit(port_idx, smcibdev->ports_going_away))
                        schedule_work(&smcibdev->port_event_work);
                break;
        default:
                break;
        }
}

void smc_ib_destroy_queue_pair(struct smc_link *lnk)
{
        if (lnk->roce_qp)
                ib_destroy_qp(lnk->roce_qp);
        lnk->roce_qp = NULL;
}

/* create a queue pair within the protection domain for a link */
int smc_ib_create_queue_pair(struct smc_link *lnk)
{
        struct ib_qp_init_attr qp_attr = {
                .event_handler = smc_ib_qp_event_handler,
                .qp_context = lnk,
                .send_cq = lnk->smcibdev->roce_cq_send,
                .recv_cq = lnk->smcibdev->roce_cq_recv,
                .srq = NULL,
                .cap = {
                        .max_send_sge = SMC_IB_MAX_SEND_SGE,
                        .max_recv_sge = lnk->wr_rx_sge_cnt,
                        .max_inline_data = 0,
                },
                .sq_sig_type = IB_SIGNAL_REQ_WR,
                .qp_type = IB_QPT_RC,
        };
        int rc;

        /* include unsolicited rdma_writes as well,
         * there are max. 2 RDMA_WRITE per 1 WR_SEND
         */
        qp_attr.cap.max_send_wr = 3 * lnk->lgr->max_send_wr;
        qp_attr.cap.max_recv_wr = lnk->lgr->max_recv_wr;
        lnk->roce_qp = ib_create_qp(lnk->roce_pd, &qp_attr);
        rc = PTR_ERR_OR_ZERO(lnk->roce_qp);
        if (IS_ERR(lnk->roce_qp))
                lnk->roce_qp = NULL;
        else
                smc_wr_remember_qp_attr(lnk);
        return rc;
}

void smc_ib_put_memory_region(struct ib_mr *mr)
{
        ib_dereg_mr(mr);
}

static int smc_ib_map_mr_sg(struct smc_buf_desc *buf_slot, u8 link_idx)
{
        unsigned int offset = 0;
        int sg_num;

        /* map the largest prefix of a dma mapped SG list */
        sg_num = ib_map_mr_sg(buf_slot->mr[link_idx],
                              buf_slot->sgt[link_idx].sgl,
                              buf_slot->sgt[link_idx].orig_nents,
                              &offset, PAGE_SIZE);

        return sg_num;
}

/* Allocate a memory region and map the dma mapped SG list of buf_slot */
int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
                             struct smc_buf_desc *buf_slot, u8 link_idx)
{
        if (buf_slot->mr[link_idx])
                return 0; /* already done */

        buf_slot->mr[link_idx] =
                ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, 1 << buf_slot->order);
        if (IS_ERR(buf_slot->mr[link_idx])) {
                int rc;

                rc = PTR_ERR(buf_slot->mr[link_idx]);
                buf_slot->mr[link_idx] = NULL;
                return rc;
        }

        if (smc_ib_map_mr_sg(buf_slot, link_idx) !=
                             buf_slot->sgt[link_idx].orig_nents)
                return -EINVAL;

        return 0;
}

bool smc_ib_is_sg_need_sync(struct smc_link *lnk,
                            struct smc_buf_desc *buf_slot)
{
        struct scatterlist *sg;
        unsigned int i;
        bool ret = false;

        if (!lnk->smcibdev->ibdev->dma_device)
                return ret;

        /* for now there is just one DMA address */
        for_each_sg(buf_slot->sgt[lnk->link_idx].sgl, sg,
                    buf_slot->sgt[lnk->link_idx].nents, i) {
                if (!sg_dma_len(sg))
                        break;
                if (dma_need_sync(lnk->smcibdev->ibdev->dma_device,
                                  sg_dma_address(sg))) {
                        ret = true;
                        goto out;
                }
        }

out:
        return ret;
}

/* synchronize buffer usage for cpu access */
void smc_ib_sync_sg_for_cpu(struct smc_link *lnk,
                            struct smc_buf_desc *buf_slot,
                            enum dma_data_direction data_direction)
{
        struct scatterlist *sg;
        unsigned int i;

        if (!(buf_slot->is_dma_need_sync & (1U << lnk->link_idx)))
                return;

        /* for now there is just one DMA address */
        for_each_sg(buf_slot->sgt[lnk->link_idx].sgl, sg,
                    buf_slot->sgt[lnk->link_idx].nents, i) {
                if (!sg_dma_len(sg))
                        break;
                ib_dma_sync_single_for_cpu(lnk->smcibdev->ibdev,
                                           sg_dma_address(sg),
                                           sg_dma_len(sg),
                                           data_direction);
        }
}

/* synchronize buffer usage for device access */
void smc_ib_sync_sg_for_device(struct smc_link *lnk,
                               struct smc_buf_desc *buf_slot,
                               enum dma_data_direction data_direction)
{
        struct scatterlist *sg;
        unsigned int i;

        if (!(buf_slot->is_dma_need_sync & (1U << lnk->link_idx)))
                return;

        /* for now there is just one DMA address */
        for_each_sg(buf_slot->sgt[lnk->link_idx].sgl, sg,
                    buf_slot->sgt[lnk->link_idx].nents, i) {
                if (!sg_dma_len(sg))
                        break;
                ib_dma_sync_single_for_device(lnk->smcibdev->ibdev,
                                              sg_dma_address(sg),
                                              sg_dma_len(sg),
                                              data_direction);
        }
}

/* Map a new TX or RX buffer SG-table to DMA */
int smc_ib_buf_map_sg(struct smc_link *lnk,
                      struct smc_buf_desc *buf_slot,
                      enum dma_data_direction data_direction)
{
        int mapped_nents;

        mapped_nents = ib_dma_map_sg(lnk->smcibdev->ibdev,
                                     buf_slot->sgt[lnk->link_idx].sgl,
                                     buf_slot->sgt[lnk->link_idx].orig_nents,
                                     data_direction);
        if (!mapped_nents)
                return -ENOMEM;

        return mapped_nents;
}

void smc_ib_buf_unmap_sg(struct smc_link *lnk,
                         struct smc_buf_desc *buf_slot,
                         enum dma_data_direction data_direction)
{
        if (!buf_slot->sgt[lnk->link_idx].sgl->dma_address)
                return; /* already unmapped */

        ib_dma_unmap_sg(lnk->smcibdev->ibdev,
                        buf_slot->sgt[lnk->link_idx].sgl,
                        buf_slot->sgt[lnk->link_idx].orig_nents,
                        data_direction);
        buf_slot->sgt[lnk->link_idx].sgl->dma_address = 0;
}

long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
{
        struct ib_cq_init_attr cqattr = {
                .cqe = SMC_MAX_CQE, .comp_vector = 0 };
        int cqe_size_order, smc_order;
        long rc;

        mutex_lock(&smcibdev->mutex);
        rc = 0;
        if (smcibdev->initialized)
                goto out;
        /* the calculated number of cq entries fits to mlx5 cq allocation */
        cqe_size_order = cache_line_size() == 128 ? 7 : 6;
        smc_order = MAX_PAGE_ORDER - cqe_size_order;
        if (SMC_MAX_CQE + 2 > (0x00000001 << smc_order) * PAGE_SIZE)
                cqattr.cqe = (0x00000001 << smc_order) * PAGE_SIZE - 2;
        smcibdev->roce_cq_send = ib_create_cq(smcibdev->ibdev,
                                              smc_wr_tx_cq_handler, NULL,
                                              smcibdev, &cqattr);
        rc = PTR_ERR_OR_ZERO(smcibdev->roce_cq_send);
        if (IS_ERR(smcibdev->roce_cq_send)) {
                smcibdev->roce_cq_send = NULL;
                goto out;
        }
        smcibdev->roce_cq_recv = ib_create_cq(smcibdev->ibdev,
                                              smc_wr_rx_cq_handler, NULL,
                                              smcibdev, &cqattr);
        rc = PTR_ERR_OR_ZERO(smcibdev->roce_cq_recv);
        if (IS_ERR(smcibdev->roce_cq_recv)) {
                smcibdev->roce_cq_recv = NULL;
                goto err;
        }
        smc_wr_add_dev(smcibdev);
        smcibdev->initialized = 1;
        goto out;

err:
        ib_destroy_cq(smcibdev->roce_cq_send);
out:
        mutex_unlock(&smcibdev->mutex);
        return rc;
}

static void smc_ib_cleanup_per_ibdev(struct smc_ib_device *smcibdev)
{
        mutex_lock(&smcibdev->mutex);
        if (!smcibdev->initialized)
                goto out;
        smcibdev->initialized = 0;
        ib_destroy_cq(smcibdev->roce_cq_recv);
        ib_destroy_cq(smcibdev->roce_cq_send);
        smc_wr_remove_dev(smcibdev);
out:
        mutex_unlock(&smcibdev->mutex);
}

static struct ib_client smc_ib_client;

static void smc_copy_netdev_ifindex(struct smc_ib_device *smcibdev, int port)
{
        struct ib_device *ibdev = smcibdev->ibdev;
        struct net_device *ndev;

        ndev = ib_device_get_netdev(ibdev, port + 1);
        if (ndev) {
                smcibdev->ndev_ifidx[port] = ndev->ifindex;
                dev_put(ndev);
        }
}

void smc_ib_ndev_change(struct net_device *ndev, unsigned long event)
{
        struct smc_ib_device *smcibdev;
        struct ib_device *libdev;
        struct net_device *lndev;
        u8 port_cnt;
        int i;

        mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(smcibdev, &smc_ib_devices.list, list) {
                port_cnt = smcibdev->ibdev->phys_port_cnt;
                for (i = 0; i < min_t(size_t, port_cnt, SMC_MAX_PORTS); i++) {
                        libdev = smcibdev->ibdev;
                        lndev = ib_device_get_netdev(libdev, i + 1);
                        dev_put(lndev);
                        if (lndev != ndev)
                                continue;
                        if (event == NETDEV_REGISTER)
                                smcibdev->ndev_ifidx[i] = ndev->ifindex;
                        if (event == NETDEV_UNREGISTER)
                                smcibdev->ndev_ifidx[i] = 0;
                }
        }
        mutex_unlock(&smc_ib_devices.mutex);
}

/* callback function for ib_register_client() */
static int smc_ib_add_dev(struct ib_device *ibdev)
{
        struct smc_ib_device *smcibdev;
        u8 port_cnt;
        int i;

        if (ibdev->node_type != RDMA_NODE_IB_CA)
                return -EOPNOTSUPP;

        smcibdev = kzalloc_obj(*smcibdev);
        if (!smcibdev)
                return -ENOMEM;

        smcibdev->ibdev = ibdev;
        INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
        atomic_set(&smcibdev->lnk_cnt, 0);
        init_waitqueue_head(&smcibdev->lnks_deleted);
        mutex_init(&smcibdev->mutex);
        mutex_lock(&smc_ib_devices.mutex);
        list_add_tail(&smcibdev->list, &smc_ib_devices.list);
        mutex_unlock(&smc_ib_devices.mutex);
        ib_set_client_data(ibdev, &smc_ib_client, smcibdev);
        INIT_IB_EVENT_HANDLER(&smcibdev->event_handler, smcibdev->ibdev,
                              smc_ib_global_event_handler);
        ib_register_event_handler(&smcibdev->event_handler);

        /* trigger reading of the port attributes */
        port_cnt = smcibdev->ibdev->phys_port_cnt;
        pr_warn_ratelimited("smc: adding ib device %s with port count %d\n",
                            smcibdev->ibdev->name, port_cnt);
        for (i = 0;
             i < min_t(size_t, port_cnt, SMC_MAX_PORTS);
             i++) {
                set_bit(i, &smcibdev->port_event_mask);
                /* determine pnetids of the port */
                if (smc_pnetid_by_dev_port(ibdev->dev.parent, i,
                                           smcibdev->pnetid[i]))
                        smc_pnetid_by_table_ib(smcibdev, i + 1);
                smc_copy_netdev_ifindex(smcibdev, i);
                if (smc_pnet_is_pnetid_set(smcibdev->pnetid[i]))
                        pr_warn_ratelimited("smc:    ib device %s port %d has pnetid %.16s%s\n",
                                            smcibdev->ibdev->name, i + 1,
                                            smcibdev->pnetid[i],
                                            smcibdev->pnetid_by_user[i] ?
                                                " (user defined)" :
                                                "");
                else
                        pr_warn_ratelimited("smc:    ib device %s port %d has no pnetid\n",
                                            smcibdev->ibdev->name, i + 1);

        }
        schedule_work(&smcibdev->port_event_work);
        return 0;
}

/* callback function for ib_unregister_client() */
static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
{
        struct smc_ib_device *smcibdev = client_data;

        mutex_lock(&smc_ib_devices.mutex);
        list_del_init(&smcibdev->list); /* remove from smc_ib_devices */
        mutex_unlock(&smc_ib_devices.mutex);
        pr_warn_ratelimited("smc: removing ib device %s\n",
                            smcibdev->ibdev->name);
        smc_smcr_terminate_all(smcibdev);
        smc_ib_cleanup_per_ibdev(smcibdev);
        ib_unregister_event_handler(&smcibdev->event_handler);
        cancel_work_sync(&smcibdev->port_event_work);
        kfree(smcibdev);
}

static struct ib_client smc_ib_client = {
        .name   = "smc_ib",
        .add    = smc_ib_add_dev,
        .remove = smc_ib_remove_dev,
};

int __init smc_ib_register_client(void)
{
        smc_ib_init_local_systemid();
        return ib_register_client(&smc_ib_client);
}

void smc_ib_unregister_client(void)
{
        ib_unregister_client(&smc_ib_client);
}