/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 *
 *   This file is part of Portals
 *   http://sourceforge.net/projects/sandiaportals/
 *
 *   Portals is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Portals is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <linux/completion.h>
#include <linux/lnet/lib-lnet.h>

#define LNET_NRB_TINY_MIN       512     /* min value for each CPT */
#define LNET_NRB_TINY           (LNET_NRB_TINY_MIN * 4)
#define LNET_NRB_SMALL_MIN      4096    /* min value for each CPT */
#define LNET_NRB_SMALL          (LNET_NRB_SMALL_MIN * 4)
#define LNET_NRB_SMALL_PAGES    1
#define LNET_NRB_LARGE_MIN      256     /* min value for each CPT */
#define LNET_NRB_LARGE          (LNET_NRB_LARGE_MIN * 4)
#define LNET_NRB_LARGE_PAGES   ((LNET_MTU + PAGE_SIZE - 1) >> \
                                 PAGE_SHIFT)

static char *forwarding = "";
module_param(forwarding, charp, 0444);
MODULE_PARM_DESC(forwarding, "Explicitly enable/disable forwarding between networks");

static int tiny_router_buffers;
module_param(tiny_router_buffers, int, 0444);
MODULE_PARM_DESC(tiny_router_buffers, "# of 0 payload messages to buffer in the router");
static int small_router_buffers;
module_param(small_router_buffers, int, 0444);
MODULE_PARM_DESC(small_router_buffers, "# of small (1 page) messages to buffer in the router");
static int large_router_buffers;
module_param(large_router_buffers, int, 0444);
MODULE_PARM_DESC(large_router_buffers, "# of large messages to buffer in the router");
static int peer_buffer_credits;
module_param(peer_buffer_credits, int, 0444);
MODULE_PARM_DESC(peer_buffer_credits, "# router buffer credits per peer");

static int auto_down = 1;
module_param(auto_down, int, 0444);
MODULE_PARM_DESC(auto_down, "Automatically mark peers down on comms error");

int
lnet_peer_buffer_credits(struct lnet_ni *ni)
{
        /* NI option overrides LNet default */
        if (ni->ni_peerrtrcredits > 0)
                return ni->ni_peerrtrcredits;
        if (peer_buffer_credits > 0)
                return peer_buffer_credits;

        /*
         * As an approximation, allow this peer the same number of router
         * buffers as it is allowed outstanding sends
         */
        return ni->ni_peertxcredits;
}

/* forward ref's */
static int lnet_router_checker(void *);

static int check_routers_before_use;
module_param(check_routers_before_use, int, 0444);
MODULE_PARM_DESC(check_routers_before_use, "Assume routers are down and ping them before use");

int avoid_asym_router_failure = 1;
module_param(avoid_asym_router_failure, int, 0644);
MODULE_PARM_DESC(avoid_asym_router_failure, "Avoid asymmetrical router failures (0 to disable)");

static int dead_router_check_interval = 60;
module_param(dead_router_check_interval, int, 0644);
MODULE_PARM_DESC(dead_router_check_interval, "Seconds between dead router health checks (<= 0 to disable)");

static int live_router_check_interval = 60;
module_param(live_router_check_interval, int, 0644);
MODULE_PARM_DESC(live_router_check_interval, "Seconds between live router health checks (<= 0 to disable)");

static int router_ping_timeout = 50;
module_param(router_ping_timeout, int, 0644);
MODULE_PARM_DESC(router_ping_timeout, "Seconds to wait for the reply to a router health query");

int
lnet_peers_start_down(void)
{
        return check_routers_before_use;
}

void
lnet_notify_locked(struct lnet_peer *lp, int notifylnd, int alive,
                   unsigned long when)
{
        if (time_before(when, lp->lp_timestamp)) { /* out of date information */
                CDEBUG(D_NET, "Out of date\n");
                return;
        }

        lp->lp_timestamp = when;                /* update timestamp */
        lp->lp_ping_deadline = 0;              /* disable ping timeout */

        if (lp->lp_alive_count &&         /* got old news */
            (!lp->lp_alive) == (!alive)) {      /* new date for old news */
                CDEBUG(D_NET, "Old news\n");
                return;
        }

        /* Flag that notification is outstanding */

        lp->lp_alive_count++;
        lp->lp_alive = !(!alive);              /* 1 bit! */
        lp->lp_notify = 1;
        lp->lp_notifylnd |= notifylnd;
        if (lp->lp_alive)
                lp->lp_ping_feats = LNET_PING_FEAT_INVAL; /* reset */

        CDEBUG(D_NET, "set %s %d\n", libcfs_nid2str(lp->lp_nid), alive);
}

static void
lnet_ni_notify_locked(struct lnet_ni *ni, struct lnet_peer *lp)
{
        int alive;
        int notifylnd;

        /*
         * Notify only in 1 thread at any time to ensure ordered notification.
         * NB individual events can be missed; the only guarantee is that you
         * always get the most recent news
         */
        if (lp->lp_notifying || !ni)
                return;

        lp->lp_notifying = 1;

        while (lp->lp_notify) {
                alive = lp->lp_alive;
                notifylnd = lp->lp_notifylnd;

                lp->lp_notifylnd = 0;
                lp->lp_notify    = 0;

                if (notifylnd && ni->ni_lnd->lnd_notify) {
                        lnet_net_unlock(lp->lp_cpt);

                        /*
                         * A new notification could happen now; I'll handle it
                         * when control returns to me
                         */
                        ni->ni_lnd->lnd_notify(ni, lp->lp_nid, alive);

                        lnet_net_lock(lp->lp_cpt);
                }
        }

        lp->lp_notifying = 0;
}

static void
lnet_rtr_addref_locked(struct lnet_peer *lp)
{
        LASSERT(lp->lp_refcount > 0);
        LASSERT(lp->lp_rtr_refcount >= 0);

        /* lnet_net_lock must be exclusively locked */
        lp->lp_rtr_refcount++;
        if (lp->lp_rtr_refcount == 1) {
                struct list_head *pos;

                /* a simple insertion sort */
                list_for_each_prev(pos, &the_lnet.ln_routers) {
                        struct lnet_peer *rtr;

                        rtr = list_entry(pos, struct lnet_peer, lp_rtr_list);
                        if (rtr->lp_nid < lp->lp_nid)
                                break;
                }

                list_add(&lp->lp_rtr_list, pos);
                /* addref for the_lnet.ln_routers */
                lnet_peer_addref_locked(lp);
                the_lnet.ln_routers_version++;
        }
}

static void
lnet_rtr_decref_locked(struct lnet_peer *lp)
{
        LASSERT(lp->lp_refcount > 0);
        LASSERT(lp->lp_rtr_refcount > 0);

        /* lnet_net_lock must be exclusively locked */
        lp->lp_rtr_refcount--;
        if (!lp->lp_rtr_refcount) {
                LASSERT(list_empty(&lp->lp_routes));

                if (lp->lp_rcd) {
                        list_add(&lp->lp_rcd->rcd_list,
                                 &the_lnet.ln_rcd_deathrow);
                        lp->lp_rcd = NULL;
                }

                list_del(&lp->lp_rtr_list);
                /* decref for the_lnet.ln_routers */
                lnet_peer_decref_locked(lp);
                the_lnet.ln_routers_version++;
        }
}

struct lnet_remotenet *
lnet_find_net_locked(__u32 net)
{
        struct lnet_remotenet *rnet;
        struct list_head *tmp;
        struct list_head *rn_list;

        LASSERT(!the_lnet.ln_shutdown);

        rn_list = lnet_net2rnethash(net);
        list_for_each(tmp, rn_list) {
                rnet = list_entry(tmp, struct lnet_remotenet, lrn_list);

                if (rnet->lrn_net == net)
                        return rnet;
        }
        return NULL;
}

static void lnet_shuffle_seed(void)
{
        static int seeded;
        __u32 lnd_type, seed[2];
        struct timespec64 ts;
        struct lnet_ni *ni;
        struct list_head *tmp;

        if (seeded)
                return;

        cfs_get_random_bytes(seed, sizeof(seed));

        /*
         * Nodes with small feet have little entropy
         * the NID for this node gives the most entropy in the low bits
         */
        list_for_each(tmp, &the_lnet.ln_nis) {
                ni = list_entry(tmp, struct lnet_ni, ni_list);
                lnd_type = LNET_NETTYP(LNET_NIDNET(ni->ni_nid));

                if (lnd_type != LOLND)
                        seed[0] ^= (LNET_NIDADDR(ni->ni_nid) | lnd_type);
        }

        ktime_get_ts64(&ts);
        cfs_srand(ts.tv_sec ^ seed[0], ts.tv_nsec ^ seed[1]);
        seeded = 1;
}

/* NB expects LNET_LOCK held */
static void
lnet_add_route_to_rnet(struct lnet_remotenet *rnet, struct lnet_route *route)
{
        unsigned int len = 0;
        unsigned int offset = 0;
        struct list_head *e;

        lnet_shuffle_seed();

        list_for_each(e, &rnet->lrn_routes) {
                len++;
        }

        /* len+1 positions to add a new entry, also prevents division by 0 */
        offset = cfs_rand() % (len + 1);
        list_for_each(e, &rnet->lrn_routes) {
                if (!offset)
                        break;
                offset--;
        }
        list_add(&route->lr_list, e);
        list_add(&route->lr_gwlist, &route->lr_gateway->lp_routes);

        the_lnet.ln_remote_nets_version++;
        lnet_rtr_addref_locked(route->lr_gateway);
}

int
lnet_add_route(__u32 net, __u32 hops, lnet_nid_t gateway,
               unsigned int priority)
{
        struct list_head *e;
        struct lnet_remotenet *rnet;
        struct lnet_remotenet *rnet2;
        struct lnet_route *route;
        struct lnet_ni *ni;
        int add_route;
        int rc;

        CDEBUG(D_NET, "Add route: net %s hops %d priority %u gw %s\n",
               libcfs_net2str(net), hops, priority, libcfs_nid2str(gateway));

        if (gateway == LNET_NID_ANY ||
            LNET_NETTYP(LNET_NIDNET(gateway)) == LOLND ||
            net == LNET_NIDNET(LNET_NID_ANY) ||
            LNET_NETTYP(net) == LOLND ||
            LNET_NIDNET(gateway) == net ||
            (hops != LNET_UNDEFINED_HOPS && (hops < 1 || hops > 255)))
                return -EINVAL;

        if (lnet_islocalnet(net))              /* it's a local network */
                return -EEXIST;

        /* Assume net, route, all new */
        LIBCFS_ALLOC(route, sizeof(*route));
        LIBCFS_ALLOC(rnet, sizeof(*rnet));
        if (!route || !rnet) {
                CERROR("Out of memory creating route %s %d %s\n",
                       libcfs_net2str(net), hops, libcfs_nid2str(gateway));
                if (route)
                        LIBCFS_FREE(route, sizeof(*route));
                if (rnet)
                        LIBCFS_FREE(rnet, sizeof(*rnet));
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&rnet->lrn_routes);
        rnet->lrn_net = net;
        route->lr_hops = hops;
        route->lr_net = net;
        route->lr_priority = priority;

        lnet_net_lock(LNET_LOCK_EX);

        rc = lnet_nid2peer_locked(&route->lr_gateway, gateway, LNET_LOCK_EX);
        if (rc) {
                lnet_net_unlock(LNET_LOCK_EX);

                LIBCFS_FREE(route, sizeof(*route));
                LIBCFS_FREE(rnet, sizeof(*rnet));

                if (rc == -EHOSTUNREACH) /* gateway is not on a local net */
                        return rc;      /* ignore the route entry */
                CERROR("Error %d creating route %s %d %s\n", rc,
                       libcfs_net2str(net), hops,
                       libcfs_nid2str(gateway));
                return rc;
        }

        LASSERT(!the_lnet.ln_shutdown);

        rnet2 = lnet_find_net_locked(net);
        if (!rnet2) {
                /* new network */
                list_add_tail(&rnet->lrn_list, lnet_net2rnethash(net));
                rnet2 = rnet;
        }

        /* Search for a duplicate route (it's a NOOP if it is) */
        add_route = 1;
        list_for_each(e, &rnet2->lrn_routes) {
                struct lnet_route *route2;

                route2 = list_entry(e, struct lnet_route, lr_list);
                if (route2->lr_gateway == route->lr_gateway) {
                        add_route = 0;
                        break;
                }

                /* our lookups must be true */
                LASSERT(route2->lr_gateway->lp_nid != gateway);
        }

        if (add_route) {
                lnet_peer_addref_locked(route->lr_gateway); /* +1 for notify */
                lnet_add_route_to_rnet(rnet2, route);

                ni = route->lr_gateway->lp_ni;
                lnet_net_unlock(LNET_LOCK_EX);

                /* XXX Assume alive */
                if (ni->ni_lnd->lnd_notify)
                        ni->ni_lnd->lnd_notify(ni, gateway, 1);

                lnet_net_lock(LNET_LOCK_EX);
        }

        /* -1 for notify or !add_route */
        lnet_peer_decref_locked(route->lr_gateway);
        lnet_net_unlock(LNET_LOCK_EX);
        rc = 0;

        if (!add_route) {
                rc = -EEXIST;
                LIBCFS_FREE(route, sizeof(*route));
        }

        if (rnet != rnet2)
                LIBCFS_FREE(rnet, sizeof(*rnet));

        /* indicate to startup the router checker if configured */
        wake_up(&the_lnet.ln_rc_waitq);

        return rc;
}

int
lnet_check_routes(void)
{
        struct lnet_remotenet *rnet;
        struct lnet_route *route;
        struct lnet_route *route2;
        struct list_head *e1;
        struct list_head *e2;
        int cpt;
        struct list_head *rn_list;
        int i;

        cpt = lnet_net_lock_current();

        for (i = 0; i < LNET_REMOTE_NETS_HASH_SIZE; i++) {
                rn_list = &the_lnet.ln_remote_nets_hash[i];
                list_for_each(e1, rn_list) {
                        rnet = list_entry(e1, struct lnet_remotenet, lrn_list);

                        route2 = NULL;
                        list_for_each(e2, &rnet->lrn_routes) {
                                lnet_nid_t nid1;
                                lnet_nid_t nid2;
                                int net;

                                route = list_entry(e2, struct lnet_route, lr_list);

                                if (!route2) {
                                        route2 = route;
                                        continue;
                                }

                                if (route->lr_gateway->lp_ni ==
                                    route2->lr_gateway->lp_ni)
                                        continue;

                                nid1 = route->lr_gateway->lp_nid;
                                nid2 = route2->lr_gateway->lp_nid;
                                net = rnet->lrn_net;

                                lnet_net_unlock(cpt);

                                CERROR("Routes to %s via %s and %s not supported\n",
                                       libcfs_net2str(net),
                                       libcfs_nid2str(nid1),
                                       libcfs_nid2str(nid2));
                                return -EINVAL;
                        }
                }
        }

        lnet_net_unlock(cpt);
        return 0;
}

int
lnet_del_route(__u32 net, lnet_nid_t gw_nid)
{
        struct lnet_peer *gateway;
        struct lnet_remotenet *rnet;
        struct lnet_route *route;
        struct list_head *e1;
        struct list_head *e2;
        int rc = -ENOENT;
        struct list_head *rn_list;
        int idx = 0;

        CDEBUG(D_NET, "Del route: net %s : gw %s\n",
               libcfs_net2str(net), libcfs_nid2str(gw_nid));

        /*
         * NB Caller may specify either all routes via the given gateway
         * or a specific route entry actual NIDs)
         */
        lnet_net_lock(LNET_LOCK_EX);
        if (net == LNET_NIDNET(LNET_NID_ANY))
                rn_list = &the_lnet.ln_remote_nets_hash[0];
        else
                rn_list = lnet_net2rnethash(net);

 again:
        list_for_each(e1, rn_list) {
                rnet = list_entry(e1, struct lnet_remotenet, lrn_list);

                if (!(net == LNET_NIDNET(LNET_NID_ANY) ||
                      net == rnet->lrn_net))
                        continue;

                list_for_each(e2, &rnet->lrn_routes) {
                        route = list_entry(e2, struct lnet_route, lr_list);

                        gateway = route->lr_gateway;
                        if (!(gw_nid == LNET_NID_ANY ||
                              gw_nid == gateway->lp_nid))
                                continue;

                        list_del(&route->lr_list);
                        list_del(&route->lr_gwlist);
                        the_lnet.ln_remote_nets_version++;

                        if (list_empty(&rnet->lrn_routes))
                                list_del(&rnet->lrn_list);
                        else
                                rnet = NULL;

                        lnet_rtr_decref_locked(gateway);
                        lnet_peer_decref_locked(gateway);

                        lnet_net_unlock(LNET_LOCK_EX);

                        LIBCFS_FREE(route, sizeof(*route));

                        if (rnet)
                                LIBCFS_FREE(rnet, sizeof(*rnet));

                        rc = 0;
                        lnet_net_lock(LNET_LOCK_EX);
                        goto again;
                }
        }

        if (net == LNET_NIDNET(LNET_NID_ANY) &&
            ++idx < LNET_REMOTE_NETS_HASH_SIZE) {
                rn_list = &the_lnet.ln_remote_nets_hash[idx];
                goto again;
        }
        lnet_net_unlock(LNET_LOCK_EX);

        return rc;
}

void
lnet_destroy_routes(void)
{
        lnet_del_route(LNET_NIDNET(LNET_NID_ANY), LNET_NID_ANY);
}

int lnet_get_rtr_pool_cfg(int idx, struct lnet_ioctl_pool_cfg *pool_cfg)
{
        int i, rc = -ENOENT, j;

        if (!the_lnet.ln_rtrpools)
                return rc;

        for (i = 0; i < LNET_NRBPOOLS; i++) {
                struct lnet_rtrbufpool *rbp;

                lnet_net_lock(LNET_LOCK_EX);
                cfs_percpt_for_each(rbp, j, the_lnet.ln_rtrpools) {
                        if (i++ != idx)
                                continue;

                        pool_cfg->pl_pools[i].pl_npages = rbp[i].rbp_npages;
                        pool_cfg->pl_pools[i].pl_nbuffers = rbp[i].rbp_nbuffers;
                        pool_cfg->pl_pools[i].pl_credits = rbp[i].rbp_credits;
                        pool_cfg->pl_pools[i].pl_mincredits = rbp[i].rbp_mincredits;
                        rc = 0;
                        break;
                }
                lnet_net_unlock(LNET_LOCK_EX);
        }

        lnet_net_lock(LNET_LOCK_EX);
        pool_cfg->pl_routing = the_lnet.ln_routing;
        lnet_net_unlock(LNET_LOCK_EX);

        return rc;
}

int
lnet_get_route(int idx, __u32 *net, __u32 *hops,
               lnet_nid_t *gateway, __u32 *alive, __u32 *priority)
{
        struct list_head *e1;
        struct list_head *e2;
        struct lnet_remotenet *rnet;
        struct lnet_route *route;
        int cpt;
        int i;
        struct list_head *rn_list;

        cpt = lnet_net_lock_current();

        for (i = 0; i < LNET_REMOTE_NETS_HASH_SIZE; i++) {
                rn_list = &the_lnet.ln_remote_nets_hash[i];
                list_for_each(e1, rn_list) {
                        rnet = list_entry(e1, struct lnet_remotenet, lrn_list);

                        list_for_each(e2, &rnet->lrn_routes) {
                                route = list_entry(e2, struct lnet_route,
                                                   lr_list);

                                if (!idx--) {
                                        *net      = rnet->lrn_net;
                                        *hops     = route->lr_hops;
                                        *priority = route->lr_priority;
                                        *gateway  = route->lr_gateway->lp_nid;
                                        *alive = lnet_is_route_alive(route);
                                        lnet_net_unlock(cpt);
                                        return 0;
                                }
                        }
                }
        }

        lnet_net_unlock(cpt);
        return -ENOENT;
}

void
lnet_swap_pinginfo(struct lnet_ping_info *info)
{
        int i;
        struct lnet_ni_status *stat;

        __swab32s(&info->pi_magic);
        __swab32s(&info->pi_features);
        __swab32s(&info->pi_pid);
        __swab32s(&info->pi_nnis);
        for (i = 0; i < info->pi_nnis && i < LNET_MAX_RTR_NIS; i++) {
                stat = &info->pi_ni[i];
                __swab64s(&stat->ns_nid);
                __swab32s(&stat->ns_status);
        }
}

/**
 * parse router-checker pinginfo, record number of down NIs for remote
 * networks on that router.
 */
static void
lnet_parse_rc_info(struct lnet_rc_data *rcd)
{
        struct lnet_ping_info *info = rcd->rcd_pinginfo;
        struct lnet_peer *gw = rcd->rcd_gateway;
        struct lnet_route *rte;

        if (!gw->lp_alive)
                return;

        if (info->pi_magic == __swab32(LNET_PROTO_PING_MAGIC))
                lnet_swap_pinginfo(info);

        /* NB always racing with network! */
        if (info->pi_magic != LNET_PROTO_PING_MAGIC) {
                CDEBUG(D_NET, "%s: Unexpected magic %08x\n",
                       libcfs_nid2str(gw->lp_nid), info->pi_magic);
                gw->lp_ping_feats = LNET_PING_FEAT_INVAL;
                return;
        }

        gw->lp_ping_feats = info->pi_features;
        if (!(gw->lp_ping_feats & LNET_PING_FEAT_MASK)) {
                CDEBUG(D_NET, "%s: Unexpected features 0x%x\n",
                       libcfs_nid2str(gw->lp_nid), gw->lp_ping_feats);
                return; /* nothing I can understand */
        }

        if (!(gw->lp_ping_feats & LNET_PING_FEAT_NI_STATUS))
                return; /* can't carry NI status info */

        list_for_each_entry(rte, &gw->lp_routes, lr_gwlist) {
                int down = 0;
                int up = 0;
                int i;

                if (gw->lp_ping_feats & LNET_PING_FEAT_RTE_DISABLED) {
                        rte->lr_downis = 1;
                        continue;
                }

                for (i = 0; i < info->pi_nnis && i < LNET_MAX_RTR_NIS; i++) {
                        struct lnet_ni_status *stat = &info->pi_ni[i];
                        lnet_nid_t nid = stat->ns_nid;

                        if (nid == LNET_NID_ANY) {
                                CDEBUG(D_NET, "%s: unexpected LNET_NID_ANY\n",
                                       libcfs_nid2str(gw->lp_nid));
                                gw->lp_ping_feats = LNET_PING_FEAT_INVAL;
                                return;
                        }

                        if (LNET_NETTYP(LNET_NIDNET(nid)) == LOLND)
                                continue;

                        if (stat->ns_status == LNET_NI_STATUS_DOWN) {
                                down++;
                                continue;
                        }

                        if (stat->ns_status == LNET_NI_STATUS_UP) {
                                if (LNET_NIDNET(nid) == rte->lr_net) {
                                        up = 1;
                                        break;
                                }
                                continue;
                        }

                        CDEBUG(D_NET, "%s: Unexpected status 0x%x\n",
                               libcfs_nid2str(gw->lp_nid), stat->ns_status);
                        gw->lp_ping_feats = LNET_PING_FEAT_INVAL;
                        return;
                }

                if (up) { /* ignore downed NIs if NI for dest network is up */
                        rte->lr_downis = 0;
                        continue;
                }
                /**
                 * if @down is zero and this route is single-hop, it means
                 * we can't find NI for target network
                 */
                if (!down && rte->lr_hops == 1)
                        down = 1;

                rte->lr_downis = down;
        }
}

static void
lnet_router_checker_event(struct lnet_event *event)
{
        struct lnet_rc_data *rcd = event->md.user_ptr;
        struct lnet_peer *lp;

        LASSERT(rcd);

        if (event->unlinked) {
                LNetInvalidateMDHandle(&rcd->rcd_mdh);
                return;
        }

        LASSERT(event->type == LNET_EVENT_SEND ||
                event->type == LNET_EVENT_REPLY);

        lp = rcd->rcd_gateway;
        LASSERT(lp);

        /*
         * NB: it's called with holding lnet_res_lock, we have a few
         * places need to hold both locks at the same time, please take
         * care of lock ordering
         */
        lnet_net_lock(lp->lp_cpt);
        if (!lnet_isrouter(lp) || lp->lp_rcd != rcd) {
                /* ignore if no longer a router or rcd is replaced */
                goto out;
        }

        if (event->type == LNET_EVENT_SEND) {
                lp->lp_ping_notsent = 0;
                if (!event->status)
                        goto out;
        }

        /* LNET_EVENT_REPLY */
        /*
         * A successful REPLY means the router is up.  If _any_ comms
         * to the router fail I assume it's down (this will happen if
         * we ping alive routers to try to detect router death before
         * apps get burned).
         */
        lnet_notify_locked(lp, 1, !event->status, cfs_time_current());

        /*
         * The router checker will wake up very shortly and do the
         * actual notification.
         * XXX If 'lp' stops being a router before then, it will still
         * have the notification pending!!!
         */
        if (avoid_asym_router_failure && !event->status)
                lnet_parse_rc_info(rcd);

 out:
        lnet_net_unlock(lp->lp_cpt);
}

static void
lnet_wait_known_routerstate(void)
{
        struct lnet_peer *rtr;
        struct list_head *entry;
        int all_known;

        LASSERT(the_lnet.ln_rc_state == LNET_RC_STATE_RUNNING);

        for (;;) {
                int cpt = lnet_net_lock_current();

                all_known = 1;
                list_for_each(entry, &the_lnet.ln_routers) {
                        rtr = list_entry(entry, struct lnet_peer, lp_rtr_list);

                        if (!rtr->lp_alive_count) {
                                all_known = 0;
                                break;
                        }
                }

                lnet_net_unlock(cpt);

                if (all_known)
                        return;

                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(cfs_time_seconds(1));
        }
}

void
lnet_router_ni_update_locked(struct lnet_peer *gw, __u32 net)
{
        struct lnet_route *rte;

        if ((gw->lp_ping_feats & LNET_PING_FEAT_NI_STATUS)) {
                list_for_each_entry(rte, &gw->lp_routes, lr_gwlist) {
                        if (rte->lr_net == net) {
                                rte->lr_downis = 0;
                                break;
                        }
                }
        }
}

static void
lnet_update_ni_status_locked(void)
{
        struct lnet_ni *ni;
        time64_t now;
        int timeout;

        LASSERT(the_lnet.ln_routing);

        timeout = router_ping_timeout +
                  max(live_router_check_interval, dead_router_check_interval);

        now = ktime_get_real_seconds();
        list_for_each_entry(ni, &the_lnet.ln_nis, ni_list) {
                if (ni->ni_lnd->lnd_type == LOLND)
                        continue;

                if (now < ni->ni_last_alive + timeout)
                        continue;

                lnet_ni_lock(ni);
                /* re-check with lock */
                if (now < ni->ni_last_alive + timeout) {
                        lnet_ni_unlock(ni);
                        continue;
                }

                LASSERT(ni->ni_status);

                if (ni->ni_status->ns_status != LNET_NI_STATUS_DOWN) {
                        CDEBUG(D_NET, "NI(%s:%d) status changed to down\n",
                               libcfs_nid2str(ni->ni_nid), timeout);
                        /*
                         * NB: so far, this is the only place to set
                         * NI status to "down"
                         */
                        ni->ni_status->ns_status = LNET_NI_STATUS_DOWN;
                }
                lnet_ni_unlock(ni);
        }
}

static void
lnet_destroy_rc_data(struct lnet_rc_data *rcd)
{
        LASSERT(list_empty(&rcd->rcd_list));
        /* detached from network */
        LASSERT(LNetMDHandleIsInvalid(rcd->rcd_mdh));

        if (rcd->rcd_gateway) {
                int cpt = rcd->rcd_gateway->lp_cpt;

                lnet_net_lock(cpt);
                lnet_peer_decref_locked(rcd->rcd_gateway);
                lnet_net_unlock(cpt);
        }

        if (rcd->rcd_pinginfo)
                LIBCFS_FREE(rcd->rcd_pinginfo, LNET_PINGINFO_SIZE);

        LIBCFS_FREE(rcd, sizeof(*rcd));
}

static struct lnet_rc_data *
lnet_create_rc_data_locked(struct lnet_peer *gateway)
{
        struct lnet_rc_data *rcd = NULL;
        struct lnet_ping_info *pi;
        struct lnet_md md;
        int rc;
        int i;

        lnet_net_unlock(gateway->lp_cpt);

        LIBCFS_ALLOC(rcd, sizeof(*rcd));
        if (!rcd)
                goto out;

        LNetInvalidateMDHandle(&rcd->rcd_mdh);
        INIT_LIST_HEAD(&rcd->rcd_list);

        LIBCFS_ALLOC(pi, LNET_PINGINFO_SIZE);
        if (!pi)
                goto out;

        for (i = 0; i < LNET_MAX_RTR_NIS; i++) {
                pi->pi_ni[i].ns_nid = LNET_NID_ANY;
                pi->pi_ni[i].ns_status = LNET_NI_STATUS_INVALID;
        }
        rcd->rcd_pinginfo = pi;

        md.start = pi;
        md.user_ptr = rcd;
        md.length = LNET_PINGINFO_SIZE;
        md.threshold = LNET_MD_THRESH_INF;
        md.options = LNET_MD_TRUNCATE;
        md.eq_handle = the_lnet.ln_rc_eqh;

        LASSERT(!LNetEQHandleIsInvalid(the_lnet.ln_rc_eqh));
        rc = LNetMDBind(md, LNET_UNLINK, &rcd->rcd_mdh);
        if (rc < 0) {
                CERROR("Can't bind MD: %d\n", rc);
                goto out;
        }
        LASSERT(!rc);

        lnet_net_lock(gateway->lp_cpt);
        /* router table changed or someone has created rcd for this gateway */
        if (!lnet_isrouter(gateway) || gateway->lp_rcd) {
                lnet_net_unlock(gateway->lp_cpt);
                goto out;
        }

        lnet_peer_addref_locked(gateway);
        rcd->rcd_gateway = gateway;
        gateway->lp_rcd = rcd;
        gateway->lp_ping_notsent = 0;

        return rcd;

 out:
        if (rcd) {
                if (!LNetMDHandleIsInvalid(rcd->rcd_mdh)) {
                        rc = LNetMDUnlink(rcd->rcd_mdh);
                        LASSERT(!rc);
                }
                lnet_destroy_rc_data(rcd);
        }

        lnet_net_lock(gateway->lp_cpt);
        return gateway->lp_rcd;
}

static int
lnet_router_check_interval(struct lnet_peer *rtr)
{
        int secs;

        secs = rtr->lp_alive ? live_router_check_interval :
                               dead_router_check_interval;
        if (secs < 0)
                secs = 0;

        return secs;
}

static void
lnet_ping_router_locked(struct lnet_peer *rtr)
{
        struct lnet_rc_data *rcd = NULL;
        unsigned long now = cfs_time_current();
        int secs;

        lnet_peer_addref_locked(rtr);

        if (rtr->lp_ping_deadline && /* ping timed out? */
            cfs_time_after(now, rtr->lp_ping_deadline))
                lnet_notify_locked(rtr, 1, 0, now);

        /* Run any outstanding notifications */

        lnet_ni_notify_locked(rtr->lp_ni, rtr);

        if (!lnet_isrouter(rtr) ||
            the_lnet.ln_rc_state != LNET_RC_STATE_RUNNING) {
                /* router table changed or router checker is shutting down */
                lnet_peer_decref_locked(rtr);
                return;
        }

        rcd = rtr->lp_rcd ?
              rtr->lp_rcd : lnet_create_rc_data_locked(rtr);

        if (!rcd)
                return;

        secs = lnet_router_check_interval(rtr);

        CDEBUG(D_NET,
               "rtr %s %d: deadline %lu ping_notsent %d alive %d alive_count %d lp_ping_timestamp %lu\n",
               libcfs_nid2str(rtr->lp_nid), secs,
               rtr->lp_ping_deadline, rtr->lp_ping_notsent,
               rtr->lp_alive, rtr->lp_alive_count, rtr->lp_ping_timestamp);

        if (secs && !rtr->lp_ping_notsent &&
            cfs_time_after(now, cfs_time_add(rtr->lp_ping_timestamp,
                                             cfs_time_seconds(secs)))) {
                int rc;
                struct lnet_process_id id;
                struct lnet_handle_md mdh;

                id.nid = rtr->lp_nid;
                id.pid = LNET_PID_LUSTRE;
                CDEBUG(D_NET, "Check: %s\n", libcfs_id2str(id));

                rtr->lp_ping_notsent   = 1;
                rtr->lp_ping_timestamp = now;

                mdh = rcd->rcd_mdh;

                if (!rtr->lp_ping_deadline) {
                        rtr->lp_ping_deadline =
                                cfs_time_shift(router_ping_timeout);
                }

                lnet_net_unlock(rtr->lp_cpt);

                rc = LNetGet(LNET_NID_ANY, mdh, id, LNET_RESERVED_PORTAL,
                             LNET_PROTO_PING_MATCHBITS, 0);

                lnet_net_lock(rtr->lp_cpt);
                if (rc)
                        rtr->lp_ping_notsent = 0; /* no event pending */
        }

        lnet_peer_decref_locked(rtr);
}

int
lnet_router_checker_start(void)
{
        struct task_struct *task;
        int rc;
        int eqsz = 0;

        LASSERT(the_lnet.ln_rc_state == LNET_RC_STATE_SHUTDOWN);

        if (check_routers_before_use &&
            dead_router_check_interval <= 0) {
                LCONSOLE_ERROR_MSG(0x10a, "'dead_router_check_interval' must be set if 'check_routers_before_use' is set\n");
                return -EINVAL;
        }

        init_completion(&the_lnet.ln_rc_signal);

        rc = LNetEQAlloc(0, lnet_router_checker_event, &the_lnet.ln_rc_eqh);
        if (rc) {
                CERROR("Can't allocate EQ(%d): %d\n", eqsz, rc);
                return -ENOMEM;
        }

        the_lnet.ln_rc_state = LNET_RC_STATE_RUNNING;
        task = kthread_run(lnet_router_checker, NULL, "router_checker");
        if (IS_ERR(task)) {
                rc = PTR_ERR(task);
                CERROR("Can't start router checker thread: %d\n", rc);
                /* block until event callback signals exit */
                wait_for_completion(&the_lnet.ln_rc_signal);
                rc = LNetEQFree(the_lnet.ln_rc_eqh);
                LASSERT(!rc);
                the_lnet.ln_rc_state = LNET_RC_STATE_SHUTDOWN;
                return -ENOMEM;
        }

        if (check_routers_before_use) {
                /*
                 * Note that a helpful side-effect of pinging all known routers
                 * at startup is that it makes them drop stale connections they
                 * may have to a previous instance of me.
                 */
                lnet_wait_known_routerstate();
        }

        return 0;
}

void
lnet_router_checker_stop(void)
{
        int rc;

        if (the_lnet.ln_rc_state == LNET_RC_STATE_SHUTDOWN)
                return;

        LASSERT(the_lnet.ln_rc_state == LNET_RC_STATE_RUNNING);
        the_lnet.ln_rc_state = LNET_RC_STATE_STOPPING;
        /* wakeup the RC thread if it's sleeping */
        wake_up(&the_lnet.ln_rc_waitq);

        /* block until event callback signals exit */
        wait_for_completion(&the_lnet.ln_rc_signal);
        LASSERT(the_lnet.ln_rc_state == LNET_RC_STATE_SHUTDOWN);

        rc = LNetEQFree(the_lnet.ln_rc_eqh);
        LASSERT(!rc);
}

static void
lnet_prune_rc_data(int wait_unlink)
{
        struct lnet_rc_data *rcd;
        struct lnet_rc_data *tmp;
        struct lnet_peer *lp;
        struct list_head head;
        int i = 2;

        if (likely(the_lnet.ln_rc_state == LNET_RC_STATE_RUNNING &&
                   list_empty(&the_lnet.ln_rcd_deathrow) &&
                   list_empty(&the_lnet.ln_rcd_zombie)))
                return;

        INIT_LIST_HEAD(&head);

        lnet_net_lock(LNET_LOCK_EX);

        if (the_lnet.ln_rc_state != LNET_RC_STATE_RUNNING) {
                /* router checker is stopping, prune all */
                list_for_each_entry(lp, &the_lnet.ln_routers,
                                    lp_rtr_list) {
                        if (!lp->lp_rcd)
                                continue;

                        LASSERT(list_empty(&lp->lp_rcd->rcd_list));
                        list_add(&lp->lp_rcd->rcd_list,
                                 &the_lnet.ln_rcd_deathrow);
                        lp->lp_rcd = NULL;
                }
        }

        /* unlink all RCDs on deathrow list */
        list_splice_init(&the_lnet.ln_rcd_deathrow, &head);

        if (!list_empty(&head)) {
                lnet_net_unlock(LNET_LOCK_EX);

                list_for_each_entry(rcd, &head, rcd_list)
                        LNetMDUnlink(rcd->rcd_mdh);

                lnet_net_lock(LNET_LOCK_EX);
        }

        list_splice_init(&head, &the_lnet.ln_rcd_zombie);

        /* release all zombie RCDs */
        while (!list_empty(&the_lnet.ln_rcd_zombie)) {
                list_for_each_entry_safe(rcd, tmp, &the_lnet.ln_rcd_zombie,
                                         rcd_list) {
                        if (LNetMDHandleIsInvalid(rcd->rcd_mdh))
                                list_move(&rcd->rcd_list, &head);
                }

                wait_unlink = wait_unlink &&
                              !list_empty(&the_lnet.ln_rcd_zombie);

                lnet_net_unlock(LNET_LOCK_EX);

                while (!list_empty(&head)) {
                        rcd = list_entry(head.next,
                                         struct lnet_rc_data, rcd_list);
                        list_del_init(&rcd->rcd_list);
                        lnet_destroy_rc_data(rcd);
                }

                if (!wait_unlink)
                        return;

                i++;
                CDEBUG(((i & (-i)) == i) ? D_WARNING : D_NET,
                       "Waiting for rc buffers to unlink\n");
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(cfs_time_seconds(1) / 4);

                lnet_net_lock(LNET_LOCK_EX);
        }

        lnet_net_unlock(LNET_LOCK_EX);
}

/*
 * This function is called to check if the RC should block indefinitely.
 * It's called from lnet_router_checker() as well as being passed to
 * wait_event_interruptible() to avoid the lost wake_up problem.
 *
 * When it's called from wait_event_interruptible() it is necessary to
 * also not sleep if the rc state is not running to avoid a deadlock
 * when the system is shutting down
 */
static inline bool
lnet_router_checker_active(void)
{
        if (the_lnet.ln_rc_state != LNET_RC_STATE_RUNNING)
                return true;

        /*
         * Router Checker thread needs to run when routing is enabled in
         * order to call lnet_update_ni_status_locked()
         */
        if (the_lnet.ln_routing)
                return true;

        return !list_empty(&the_lnet.ln_routers) &&
                (live_router_check_interval > 0 ||
                 dead_router_check_interval > 0);
}

static int
lnet_router_checker(void *arg)
{
        struct lnet_peer *rtr;
        struct list_head *entry;

        cfs_block_allsigs();

        while (the_lnet.ln_rc_state == LNET_RC_STATE_RUNNING) {
                __u64 version;
                int cpt;
                int cpt2;

                cpt = lnet_net_lock_current();
rescan:
                version = the_lnet.ln_routers_version;

                list_for_each(entry, &the_lnet.ln_routers) {
                        rtr = list_entry(entry, struct lnet_peer, lp_rtr_list);

                        cpt2 = lnet_cpt_of_nid_locked(rtr->lp_nid);
                        if (cpt != cpt2) {
                                lnet_net_unlock(cpt);
                                cpt = cpt2;
                                lnet_net_lock(cpt);
                                /* the routers list has changed */
                                if (version != the_lnet.ln_routers_version)
                                        goto rescan;
                        }

                        lnet_ping_router_locked(rtr);

                        /* NB dropped lock */
                        if (version != the_lnet.ln_routers_version) {
                                /* the routers list has changed */
                                goto rescan;
                        }
                }

                if (the_lnet.ln_routing)
                        lnet_update_ni_status_locked();

                lnet_net_unlock(cpt);

                lnet_prune_rc_data(0); /* don't wait for UNLINK */

                /*
                 * Call schedule_timeout() here always adds 1 to load average
                 * because kernel counts # active tasks as nr_running
                 * + nr_uninterruptible.
                 */
                /*
                 * if there are any routes then wakeup every second.  If
                 * there are no routes then sleep indefinitely until woken
                 * up by a user adding a route
                 */
                if (!lnet_router_checker_active())
                        wait_event_interruptible(the_lnet.ln_rc_waitq,
                                                 lnet_router_checker_active());
                else
                        wait_event_interruptible_timeout(the_lnet.ln_rc_waitq,
                                                         false,
                                                         cfs_time_seconds(1));
        }

        lnet_prune_rc_data(1); /* wait for UNLINK */

        the_lnet.ln_rc_state = LNET_RC_STATE_SHUTDOWN;
        complete(&the_lnet.ln_rc_signal);
        /* The unlink event callback will signal final completion */
        return 0;
}

void
lnet_destroy_rtrbuf(struct lnet_rtrbuf *rb, int npages)
{
        int sz = offsetof(struct lnet_rtrbuf, rb_kiov[npages]);

        while (--npages >= 0)
                __free_page(rb->rb_kiov[npages].bv_page);

        LIBCFS_FREE(rb, sz);
}

static struct lnet_rtrbuf *
lnet_new_rtrbuf(struct lnet_rtrbufpool *rbp, int cpt)
{
        int npages = rbp->rbp_npages;
        int sz = offsetof(struct lnet_rtrbuf, rb_kiov[npages]);
        struct page *page;
        struct lnet_rtrbuf *rb;
        int i;

        LIBCFS_CPT_ALLOC(rb, lnet_cpt_table(), cpt, sz);
        if (!rb)
                return NULL;

        rb->rb_pool = rbp;

        for (i = 0; i < npages; i++) {
                page = alloc_pages_node(
                                cfs_cpt_spread_node(lnet_cpt_table(), cpt),
                                GFP_KERNEL | __GFP_ZERO, 0);
                if (!page) {
                        while (--i >= 0)
                                __free_page(rb->rb_kiov[i].bv_page);

                        LIBCFS_FREE(rb, sz);
                        return NULL;
                }

                rb->rb_kiov[i].bv_len = PAGE_SIZE;
                rb->rb_kiov[i].bv_offset = 0;
                rb->rb_kiov[i].bv_page = page;
        }

        return rb;
}

static void
lnet_rtrpool_free_bufs(struct lnet_rtrbufpool *rbp, int cpt)
{
        int npages = rbp->rbp_npages;
        struct list_head tmp;
        struct lnet_rtrbuf *rb;
        struct lnet_rtrbuf *temp;

        if (!rbp->rbp_nbuffers) /* not initialized or already freed */
                return;

        INIT_LIST_HEAD(&tmp);

        lnet_net_lock(cpt);
        lnet_drop_routed_msgs_locked(&rbp->rbp_msgs, cpt);
        list_splice_init(&rbp->rbp_bufs, &tmp);
        rbp->rbp_req_nbuffers = 0;
        rbp->rbp_nbuffers = 0;
        rbp->rbp_credits = 0;
        rbp->rbp_mincredits = 0;
        lnet_net_unlock(cpt);

        /* Free buffers on the free list. */
        list_for_each_entry_safe(rb, temp, &tmp, rb_list) {
                list_del(&rb->rb_list);
                lnet_destroy_rtrbuf(rb, npages);
        }
}

static int
lnet_rtrpool_adjust_bufs(struct lnet_rtrbufpool *rbp, int nbufs, int cpt)
{
        struct list_head rb_list;
        struct lnet_rtrbuf *rb;
        int num_rb;
        int num_buffers = 0;
        int old_req_nbufs;
        int npages = rbp->rbp_npages;

        lnet_net_lock(cpt);
        /*
         * If we are called for less buffers than already in the pool, we
         * just lower the req_nbuffers number and excess buffers will be
         * thrown away as they are returned to the free list.  Credits
         * then get adjusted as well.
         * If we already have enough buffers allocated to serve the
         * increase requested, then we can treat that the same way as we
         * do the decrease.
         */
        num_rb = nbufs - rbp->rbp_nbuffers;
        if (nbufs <= rbp->rbp_req_nbuffers || num_rb <= 0) {
                rbp->rbp_req_nbuffers = nbufs;
                lnet_net_unlock(cpt);
                return 0;
        }
        /*
         * store the older value of rbp_req_nbuffers and then set it to
         * the new request to prevent lnet_return_rx_credits_locked() from
         * freeing buffers that we need to keep around
         */
        old_req_nbufs = rbp->rbp_req_nbuffers;
        rbp->rbp_req_nbuffers = nbufs;
        lnet_net_unlock(cpt);

        INIT_LIST_HEAD(&rb_list);

        /*
         * allocate the buffers on a local list first.  If all buffers are
         * allocated successfully then join this list to the rbp buffer
         * list. If not then free all allocated buffers.
         */
        while (num_rb-- > 0) {
                rb = lnet_new_rtrbuf(rbp, cpt);
                if (!rb) {
                        CERROR("Failed to allocate %d route bufs of %d pages\n",
                               nbufs, npages);

                        lnet_net_lock(cpt);
                        rbp->rbp_req_nbuffers = old_req_nbufs;
                        lnet_net_unlock(cpt);

                        goto failed;
                }

                list_add(&rb->rb_list, &rb_list);
                num_buffers++;
        }

        lnet_net_lock(cpt);

        list_splice_tail(&rb_list, &rbp->rbp_bufs);
        rbp->rbp_nbuffers += num_buffers;
        rbp->rbp_credits += num_buffers;
        rbp->rbp_mincredits = rbp->rbp_credits;
        /*
         * We need to schedule blocked msg using the newly
         * added buffers.
         */
        while (!list_empty(&rbp->rbp_bufs) &&
               !list_empty(&rbp->rbp_msgs))
                lnet_schedule_blocked_locked(rbp);

        lnet_net_unlock(cpt);

        return 0;

failed:
        while (!list_empty(&rb_list)) {
                rb = list_entry(rb_list.next, struct lnet_rtrbuf, rb_list);
                list_del(&rb->rb_list);
                lnet_destroy_rtrbuf(rb, npages);
        }

        return -ENOMEM;
}

static void
lnet_rtrpool_init(struct lnet_rtrbufpool *rbp, int npages)
{
        INIT_LIST_HEAD(&rbp->rbp_msgs);
        INIT_LIST_HEAD(&rbp->rbp_bufs);

        rbp->rbp_npages = npages;
        rbp->rbp_credits = 0;
        rbp->rbp_mincredits = 0;
}

void
lnet_rtrpools_free(int keep_pools)
{
        struct lnet_rtrbufpool *rtrp;
        int i;

        if (!the_lnet.ln_rtrpools) /* uninitialized or freed */
                return;

        cfs_percpt_for_each(rtrp, i, the_lnet.ln_rtrpools) {
                lnet_rtrpool_free_bufs(&rtrp[LNET_TINY_BUF_IDX], i);
                lnet_rtrpool_free_bufs(&rtrp[LNET_SMALL_BUF_IDX], i);
                lnet_rtrpool_free_bufs(&rtrp[LNET_LARGE_BUF_IDX], i);
        }

        if (!keep_pools) {
                cfs_percpt_free(the_lnet.ln_rtrpools);
                the_lnet.ln_rtrpools = NULL;
        }
}

static int
lnet_nrb_tiny_calculate(void)
{
        int nrbs = LNET_NRB_TINY;

        if (tiny_router_buffers < 0) {
                LCONSOLE_ERROR_MSG(0x10c,
                                   "tiny_router_buffers=%d invalid when routing enabled\n",
                                   tiny_router_buffers);
                return -EINVAL;
        }

        if (tiny_router_buffers > 0)
                nrbs = tiny_router_buffers;

        nrbs /= LNET_CPT_NUMBER;
        return max(nrbs, LNET_NRB_TINY_MIN);
}

static int
lnet_nrb_small_calculate(void)
{
        int nrbs = LNET_NRB_SMALL;

        if (small_router_buffers < 0) {
                LCONSOLE_ERROR_MSG(0x10c,
                                   "small_router_buffers=%d invalid when routing enabled\n",
                                   small_router_buffers);
                return -EINVAL;
        }

        if (small_router_buffers > 0)
                nrbs = small_router_buffers;

        nrbs /= LNET_CPT_NUMBER;
        return max(nrbs, LNET_NRB_SMALL_MIN);
}

static int
lnet_nrb_large_calculate(void)
{
        int nrbs = LNET_NRB_LARGE;

        if (large_router_buffers < 0) {
                LCONSOLE_ERROR_MSG(0x10c,
                                   "large_router_buffers=%d invalid when routing enabled\n",
                                   large_router_buffers);
                return -EINVAL;
        }

        if (large_router_buffers > 0)
                nrbs = large_router_buffers;

        nrbs /= LNET_CPT_NUMBER;
        return max(nrbs, LNET_NRB_LARGE_MIN);
}

int
lnet_rtrpools_alloc(int im_a_router)
{
        struct lnet_rtrbufpool *rtrp;
        int nrb_tiny;
        int nrb_small;
        int nrb_large;
        int rc;
        int i;

        if (!strcmp(forwarding, "")) {
                /* not set either way */
                if (!im_a_router)
                        return 0;
        } else if (!strcmp(forwarding, "disabled")) {
                /* explicitly disabled */
                return 0;
        } else if (!strcmp(forwarding, "enabled")) {
                /* explicitly enabled */
        } else {
                LCONSOLE_ERROR_MSG(0x10b, "'forwarding' not set to either 'enabled' or 'disabled'\n");
                return -EINVAL;
        }

        nrb_tiny = lnet_nrb_tiny_calculate();
        if (nrb_tiny < 0)
                return -EINVAL;

        nrb_small = lnet_nrb_small_calculate();
        if (nrb_small < 0)
                return -EINVAL;

        nrb_large = lnet_nrb_large_calculate();
        if (nrb_large < 0)
                return -EINVAL;

        the_lnet.ln_rtrpools = cfs_percpt_alloc(lnet_cpt_table(),
                                                LNET_NRBPOOLS *
                                                sizeof(struct lnet_rtrbufpool));
        if (!the_lnet.ln_rtrpools) {
                LCONSOLE_ERROR_MSG(0x10c,
                                   "Failed to initialize router buffe pool\n");
                return -ENOMEM;
        }

        cfs_percpt_for_each(rtrp, i, the_lnet.ln_rtrpools) {
                lnet_rtrpool_init(&rtrp[LNET_TINY_BUF_IDX], 0);
                rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_TINY_BUF_IDX],
                                              nrb_tiny, i);
                if (rc)
                        goto failed;

                lnet_rtrpool_init(&rtrp[LNET_SMALL_BUF_IDX],
                                  LNET_NRB_SMALL_PAGES);
                rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_SMALL_BUF_IDX],
                                              nrb_small, i);
                if (rc)
                        goto failed;

                lnet_rtrpool_init(&rtrp[LNET_LARGE_BUF_IDX],
                                  LNET_NRB_LARGE_PAGES);
                rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_LARGE_BUF_IDX],
                                              nrb_large, i);
                if (rc)
                        goto failed;
        }

        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_routing = 1;
        lnet_net_unlock(LNET_LOCK_EX);

        return 0;

 failed:
        lnet_rtrpools_free(0);
        return rc;
}

static int
lnet_rtrpools_adjust_helper(int tiny, int small, int large)
{
        int nrb = 0;
        int rc = 0;
        int i;
        struct lnet_rtrbufpool *rtrp;

        /*
         * If the provided values for each buffer pool are different than the
         * configured values, we need to take action.
         */
        if (tiny >= 0) {
                tiny_router_buffers = tiny;
                nrb = lnet_nrb_tiny_calculate();
                cfs_percpt_for_each(rtrp, i, the_lnet.ln_rtrpools) {
                        rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_TINY_BUF_IDX],
                                                      nrb, i);
                        if (rc)
                                return rc;
                }
        }
        if (small >= 0) {
                small_router_buffers = small;
                nrb = lnet_nrb_small_calculate();
                cfs_percpt_for_each(rtrp, i, the_lnet.ln_rtrpools) {
                        rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_SMALL_BUF_IDX],
                                                      nrb, i);
                        if (rc)
                                return rc;
                }
        }
        if (large >= 0) {
                large_router_buffers = large;
                nrb = lnet_nrb_large_calculate();
                cfs_percpt_for_each(rtrp, i, the_lnet.ln_rtrpools) {
                        rc = lnet_rtrpool_adjust_bufs(&rtrp[LNET_LARGE_BUF_IDX],
                                                      nrb, i);
                        if (rc)
                                return rc;
                }
        }

        return 0;
}

int
lnet_rtrpools_adjust(int tiny, int small, int large)
{
        /*
         * this function doesn't revert the changes if adding new buffers
         * failed.  It's up to the user space caller to revert the
         * changes.
         */
        if (!the_lnet.ln_routing)
                return 0;

        return lnet_rtrpools_adjust_helper(tiny, small, large);
}

int
lnet_rtrpools_enable(void)
{
        int rc = 0;

        if (the_lnet.ln_routing)
                return 0;

        if (!the_lnet.ln_rtrpools)
                /*
                 * If routing is turned off, and we have never
                 * initialized the pools before, just call the
                 * standard buffer pool allocation routine as
                 * if we are just configuring this for the first
                 * time.
                 */
                rc = lnet_rtrpools_alloc(1);
        else
                rc = lnet_rtrpools_adjust_helper(0, 0, 0);
        if (rc)
                return rc;

        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_routing = 1;

        the_lnet.ln_ping_info->pi_features &= ~LNET_PING_FEAT_RTE_DISABLED;
        lnet_net_unlock(LNET_LOCK_EX);

        return rc;
}

void
lnet_rtrpools_disable(void)
{
        if (!the_lnet.ln_routing)
                return;

        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_routing = 0;
        the_lnet.ln_ping_info->pi_features |= LNET_PING_FEAT_RTE_DISABLED;

        tiny_router_buffers = 0;
        small_router_buffers = 0;
        large_router_buffers = 0;
        lnet_net_unlock(LNET_LOCK_EX);
        lnet_rtrpools_free(1);
}

int
lnet_notify(struct lnet_ni *ni, lnet_nid_t nid, int alive, unsigned long when)
{
        struct lnet_peer *lp = NULL;
        unsigned long now = cfs_time_current();
        int cpt = lnet_cpt_of_nid(nid);

        LASSERT(!in_interrupt());

        CDEBUG(D_NET, "%s notifying %s: %s\n",
               !ni ? "userspace" : libcfs_nid2str(ni->ni_nid),
               libcfs_nid2str(nid),
               alive ? "up" : "down");

        if (ni &&
            LNET_NIDNET(ni->ni_nid) != LNET_NIDNET(nid)) {
                CWARN("Ignoring notification of %s %s by %s (different net)\n",
                      libcfs_nid2str(nid), alive ? "birth" : "death",
                      libcfs_nid2str(ni->ni_nid));
                return -EINVAL;
        }

        /* can't do predictions... */
        if (cfs_time_after(when, now)) {
                CWARN("Ignoring prediction from %s of %s %s %ld seconds in the future\n",
                      !ni ? "userspace" : libcfs_nid2str(ni->ni_nid),
                      libcfs_nid2str(nid), alive ? "up" : "down",
                      cfs_duration_sec(cfs_time_sub(when, now)));
                return -EINVAL;
        }

        if (ni && !alive &&          /* LND telling me she's down */
            !auto_down) {                      /* auto-down disabled */
                CDEBUG(D_NET, "Auto-down disabled\n");
                return 0;
        }

        lnet_net_lock(cpt);

        if (the_lnet.ln_shutdown) {
                lnet_net_unlock(cpt);
                return -ESHUTDOWN;
        }

        lp = lnet_find_peer_locked(the_lnet.ln_peer_tables[cpt], nid);
        if (!lp) {
                /* nid not found */
                lnet_net_unlock(cpt);
                CDEBUG(D_NET, "%s not found\n", libcfs_nid2str(nid));
                return 0;
        }

        /*
         * We can't fully trust LND on reporting exact peer last_alive
         * if he notifies us about dead peer. For example ksocklnd can
         * call us with when == _time_when_the_node_was_booted_ if
         * no connections were successfully established
         */
        if (ni && !alive && when < lp->lp_last_alive)
                when = lp->lp_last_alive;

        lnet_notify_locked(lp, !ni, alive, when);

        if (ni)
                lnet_ni_notify_locked(ni, lp);

        lnet_peer_decref_locked(lp);

        lnet_net_unlock(cpt);
        return 0;
}
EXPORT_SYMBOL(lnet_notify);