[fs/lustre-release.git] / lnet / lnet / router.c

/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2011, 2017, Intel Corporation.
 *
 *   This file is part of Lustre, https://wiki.whamcloud.com/
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Portals; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <linux/random.h>
#include <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)

extern unsigned int lnet_current_net_count;

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_net *net)
{
        /* NI option overrides LNet default */
        if (net->net_tunables.lct_peer_rtr_credits > 0)
                return net->net_tunables.lct_peer_rtr_credits;
        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 net->net_tunables.lct_peer_tx_credits;
}

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)");

int dead_router_check_interval = INT_MIN;
module_param(dead_router_check_interval, int, 0444);
MODULE_PARM_DESC(dead_router_check_interval, "(DEPRECATED - Use alive_router_check_interval)");

int live_router_check_interval = INT_MIN;
module_param(live_router_check_interval, int, 0444);
MODULE_PARM_DESC(live_router_check_interval, "(DEPRECATED - Use alive_router_check_interval)");

int alive_router_check_interval = 60;
module_param(alive_router_check_interval, int, 0644);
MODULE_PARM_DESC(alive_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");

/*
 * A value between 0 and 100. 0 meaning that even if router's interfaces
 * have the worse health still consider the gateway usable.
 * 100 means that at least one interface on the route's remote net is 100%
 * healthy to consider the route alive.
 * The default is set to 100 to ensure we maintain the original behavior.
 */
unsigned int router_sensitivity_percentage = 100;
static int rtr_sensitivity_set(const char *val, cfs_kernel_param_arg_t *kp);
static struct kernel_param_ops param_ops_rtr_sensitivity = {
        .set = rtr_sensitivity_set,
        .get = param_get_int,
};
#define param_check_rtr_sensitivity(name, p) \
                __param_check(name, p, int)
#ifdef HAVE_KERNEL_PARAM_OPS
module_param(router_sensitivity_percentage, rtr_sensitivity, S_IRUGO|S_IWUSR);
#else
module_param_call(router_sensitivity_percentage, rtr_sensitivity_set, param_get_int,
                  &router_sensitivity_percentage, S_IRUGO|S_IWUSR);
#endif
MODULE_PARM_DESC(router_sensitivity_percentage,
                "How healthy a gateway should be to be used in percent");

static int
rtr_sensitivity_set(const char *val, cfs_kernel_param_arg_t *kp)
{
        int rc;
        unsigned *sen = (unsigned *)kp->arg;
        unsigned long value;

        rc = kstrtoul(val, 0, &value);
        if (rc) {
                CERROR("Invalid module parameter value for 'router_sensitivity_percentage'\n");
                return rc;
        }

        if (value < 0 || value > 100) {
                CERROR("Invalid value: %lu for 'router_sensitivity_percentage'\n", value);
                return -EINVAL;
        }

        /*
         * The purpose of locking the api_mutex here is to ensure that
         * the correct value ends up stored properly.
         */
        mutex_lock(&the_lnet.ln_api_mutex);

        *sen = value;

        mutex_unlock(&the_lnet.ln_api_mutex);

        return 0;
}

void
lnet_rtr_transfer_to_peer(struct lnet_peer *src, struct lnet_peer *target)
{
        struct lnet_route *route;

        lnet_net_lock(LNET_LOCK_EX);
        target->lp_rtr_refcount += src->lp_rtr_refcount;
        /* move the list of queued messages to the new peer */
        list_splice_init(&src->lp_rtrq, &target->lp_rtrq);
        /* move all the routes that reference the peer */
        list_splice_init(&src->lp_routes, &target->lp_routes);
        /* update all the routes to point to the new peer */
        list_for_each_entry(route, &target->lp_routes, lr_gwlist)
                route->lr_gateway = target;
        /* remove the old peer from the ln_routers list */
        list_del_init(&src->lp_rtr_list);
        /* add the new peer to the ln_routers list */
        if (list_empty(&target->lp_rtr_list)) {
                lnet_peer_addref_locked(target);
                list_add_tail(&target->lp_rtr_list, &the_lnet.ln_routers);
        }
        /* reset the ref count on the old peer and decrement its ref count */
        src->lp_rtr_refcount = 0;
        lnet_peer_decref_locked(src);
        /* update the router version */
        the_lnet.ln_routers_version++;
        lnet_net_unlock(LNET_LOCK_EX);
}

int
lnet_peers_start_down(void)
{
        return check_routers_before_use;
}

/*
 * A net is alive if at least one gateway NI on the network is alive.
 */
static bool
lnet_is_gateway_net_alive(struct lnet_peer_net *lpn)
{
        struct lnet_peer_ni *lpni;

        list_for_each_entry(lpni, &lpn->lpn_peer_nis, lpni_peer_nis) {
                if (lnet_is_peer_ni_alive(lpni))
                        return true;
        }

        return false;
}

/*
 * a gateway is alive only if all its nets are alive
 * called with cpt lock held
 */
bool lnet_is_gateway_alive(struct lnet_peer *gw)
{
        struct lnet_peer_net *lpn;

        list_for_each_entry(lpn, &gw->lp_peer_nets, lpn_peer_nets) {
                if (!lnet_is_gateway_net_alive(lpn))
                        return false;
        }

        return true;
}

/*
 * lnet_is_route_alive() needs to be called with cpt lock held
 * A route is alive if the gateway can route between the local network and
 * the remote network of the route.
 * This means at least one NI is alive on each of the local and remote
 * networks of the gateway.
 */
bool lnet_is_route_alive(struct lnet_route *route)
{
        struct lnet_peer *gw = route->lr_gateway;
        struct lnet_peer_net *llpn;
        struct lnet_peer_net *rlpn;
        bool route_alive;

        /*
         * if discovery is disabled then rely on the cached aliveness
         * information. This is handicapped information which we log when
         * we receive the discovery ping response. The most uptodate
         * aliveness information can only be obtained when discovery is
         * enabled.
         */
        if (lnet_is_discovery_disabled(gw))
                return route->lr_alive;

        /*
         * check the gateway's interfaces on the route rnet to make sure
         * that the gateway is viable.
         */
        llpn = lnet_peer_get_net_locked(gw, route->lr_lnet);
        if (!llpn)
                return false;

        route_alive = lnet_is_gateway_net_alive(llpn);

        if (avoid_asym_router_failure) {
                rlpn = lnet_peer_get_net_locked(gw, route->lr_net);
                if (!rlpn)
                        return false;
                route_alive = route_alive &&
                              lnet_is_gateway_net_alive(rlpn);
        }

        if (!route_alive)
                return route_alive;

        spin_lock(&gw->lp_lock);
        if (!(gw->lp_state & LNET_PEER_ROUTER_ENABLED)) {
                if (gw->lp_rtr_refcount > 0)
                        CERROR("peer %s is being used as a gateway but routing feature is not turned on\n",
                               libcfs_nid2str(gw->lp_primary_nid));
                route_alive = false;
        }
        spin_unlock(&gw->lp_lock);

        return route_alive;
}

void
lnet_consolidate_routes_locked(struct lnet_peer *orig_lp,
                               struct lnet_peer *new_lp)
{
        struct lnet_peer_ni *lpni;
        struct lnet_route *route;

        /*
         * Although a route is correlated with a peer, but when it's added
         * a specific NID is used. That NID refers to a peer_ni within
         * a peer. There could be other peer_nis on the same net, which
         * can be used to send to that gateway. However when we are
         * consolidating gateways because of discovery, the nid used to
         * add the route might've moved between gateway peers. In this
         * case we want to move the route to the new gateway as well. The
         * intent here is not to confuse the user who added the route.
         */
        list_for_each_entry(route, &orig_lp->lp_routes, lr_gwlist) {
                lpni = lnet_peer_get_ni_locked(orig_lp, route->lr_nid);
                if (!lpni) {
                        lnet_net_lock(LNET_LOCK_EX);
                        list_move(&route->lr_gwlist, &new_lp->lp_routes);
                        lnet_net_unlock(LNET_LOCK_EX);
                }
        }

}

static inline void
lnet_set_route_aliveness(struct lnet_route *route, bool alive)
{
        /* Log when there's a state change */
        if (route->lr_alive != alive) {
                CERROR("route to %s through %s has gone from %s to %s\n",
                       libcfs_net2str(route->lr_net),
                       libcfs_nid2str(route->lr_gateway->lp_primary_nid),
                       (route->lr_alive) ? "up" : "down",
                       alive ? "up" : "down");
                route->lr_alive = alive;
        }
}

void
lnet_router_discovery_ping_reply(struct lnet_peer *lp)
{
        struct lnet_ping_buffer *pbuf = lp->lp_data;
        struct lnet_remotenet *rnet;
        struct lnet_peer_net *llpn;
        struct lnet_route *route;
        bool net_up = false;
        unsigned lp_state;
        __u32 net, net2;
        int i, j;


        spin_lock(&lp->lp_lock);
        lp_state = lp->lp_state;

        /* only handle replies if discovery is disabled. */
        if (!lnet_is_discovery_disabled_locked(lp)) {
                spin_unlock(&lp->lp_lock);
                return;
        }

        spin_unlock(&lp->lp_lock);

        if (lp_state & LNET_PEER_PING_FAILED ||
            pbuf->pb_info.pi_features & LNET_PING_FEAT_RTE_DISABLED) {
                CDEBUG(D_NET, "Set routes down for gw %s because %s %d\n",
                       libcfs_nid2str(lp->lp_primary_nid),
                       lp_state & LNET_PEER_PING_FAILED ? "ping failed" :
                       "route feature is disabled", lp->lp_ping_error);
                /* If the ping failed or the peer has routing disabled then
                 * mark the routes served by this peer down
                 */
                list_for_each_entry(route, &lp->lp_routes, lr_gwlist)
                        lnet_set_route_aliveness(route, false);
                return;
        }

        CDEBUG(D_NET, "Discovery is disabled. Processing reply for gw: %s\n",
               libcfs_nid2str(lp->lp_primary_nid));

        /*
         * examine the ping response:
         * For each NID in the ping response, extract the net
         * if the net exists on our remote net list then
         * iterate over the routes on the rnet and if:
         *      The route's local net is healthy and
         *      The remote net status is UP, then mark the route up
         * otherwise mark the route down
         */
        for (i = 1; i < pbuf->pb_info.pi_nnis; i++) {
                net = LNET_NIDNET(pbuf->pb_info.pi_ni[i].ns_nid);
                rnet = lnet_find_rnet_locked(net);
                if (!rnet)
                        continue;
                list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
                        /* check if this is the route's gateway */
                        if (lp->lp_primary_nid !=
                            route->lr_gateway->lp_primary_nid)
                                continue;

                        llpn = lnet_peer_get_net_locked(lp, route->lr_lnet);
                        if (!llpn) {
                                lnet_set_route_aliveness(route, false);
                                continue;
                        }

                        if (!lnet_is_gateway_net_alive(llpn)) {
                                lnet_set_route_aliveness(route, false);
                                continue;
                        }

                        if (avoid_asym_router_failure &&
                            pbuf->pb_info.pi_ni[i].ns_status !=
                                LNET_NI_STATUS_UP) {
                                net_up = false;

                                /*
                                 * revisit all previous NIDs and check if
                                 * any on the network we're examining is
                                 * up. If at least one is up then we consider
                                 * the route to be alive.
                                 */
                                for (j = 1; j < i; j++) {
                                        net2 = LNET_NIDNET(pbuf->pb_info.
                                                           pi_ni[j].ns_nid);
                                        if (net2 == net &&
                                            pbuf->pb_info.pi_ni[j].ns_status ==
                                                LNET_NI_STATUS_UP)
                                                net_up = true;
                                }
                                if (!net_up) {
                                        lnet_set_route_aliveness(route, false);
                                        continue;
                                }
                        }

                        lnet_set_route_aliveness(route, true);
                }
        }
}

void
lnet_router_discovery_complete(struct lnet_peer *lp)
{
        struct lnet_peer_ni *lpni = NULL;
        struct lnet_route *route;

        spin_lock(&lp->lp_lock);
        lp->lp_state &= ~LNET_PEER_RTR_DISCOVERY;
        lp->lp_state |= LNET_PEER_RTR_DISCOVERED;
        spin_unlock(&lp->lp_lock);

        /*
         * Router discovery successful? All peer information would've been
         * updated already. No need to do any more processing
         */
        if (!lp->lp_dc_error)
                return;
        /*
         * discovery failed? then we need to set the status of each lpni
         * to DOWN. It will be updated the next time we discover the
         * router. For router peer NIs not on local networks, we never send
         * messages directly to them, so their health will always remain
         * at maximum. We can only tell if they are up or down from the
         * status returned in the PING response. If we fail to get that
         * status in our scheduled router discovery, then we'll assume
         * it's down until we're told otherwise.
         */
        CDEBUG(D_NET, "%s: Router discovery failed %d\n",
               libcfs_nid2str(lp->lp_primary_nid), lp->lp_dc_error);
        while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL)
                lpni->lpni_ns_status = LNET_NI_STATUS_DOWN;

        list_for_each_entry(route, &lp->lp_routes, lr_gwlist)
                lnet_set_route_aliveness(route, false);
}

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

        /* lnet_net_lock must be exclusively locked */
        lp->lp_rtr_refcount++;
        if (lp->lp_rtr_refcount == 1) {
                list_add_tail(&lp->lp_rtr_list, &the_lnet.ln_routers);
                /* 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(atomic_read(&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 == 0) {
                LASSERT(list_empty(&lp->lp_routes));

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

        LASSERT(the_lnet.ln_state == LNET_STATE_RUNNING);

        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;
        struct lnet_ni *ni = NULL;

        if (seeded)
                return;

        /* Nodes with small feet have little entropy
         * the NID for this node gives the most entropy in the low bits */
        while ((ni = lnet_get_next_ni_locked(NULL, ni)))
                add_device_randomness(&ni->ni_nid, sizeof(ni->ni_nid));

        seeded = 1;
}

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

        lnet_shuffle_seed();

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

        /*
         * Randomly adding routes to the list is done to ensure that when
         * different nodes are using the same list of routers, they end up
         * preferring different routers.
         */
        offset = prandom_u32_max(len + 1);
        list_for_each(e, &rnet->lrn_routes) {
                if (offset == 0)
                        break;
                offset--;
        }
        list_add(&route->lr_list, e);
        /*
         * force a router check on the gateway to make sure the route is
         * alive
         */
        list_for_each_entry(lpn, &route->lr_gateway->lp_peer_nets,
                            lpn_peer_nets) {
                lpn->lpn_rtrcheck_timestamp = 0;
        }

        the_lnet.ln_remote_nets_version++;

        /* add the route on the gateway list */
        list_add(&route->lr_gwlist, &route->lr_gateway->lp_routes);

        /* take a router reference count on the gateway */
        lnet_rtr_addref_locked(route->lr_gateway);
}

int
lnet_add_route(__u32 net, __u32 hops, lnet_nid_t gateway,
               __u32 priority, __u32 sensitivity)
{
        struct list_head *route_entry;
        struct lnet_remotenet *rnet;
        struct lnet_remotenet *rnet2;
        struct lnet_route *route;
        struct lnet_peer_ni *lpni;
        struct lnet_peer *gw;
        int add_route;
        int rc;

        CDEBUG(D_NET, "Add route: remote 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;

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

        if (!lnet_islocalnet(LNET_NIDNET(gateway))) {
                CERROR("Cannot add route with gateway %s. There is no local interface configured on LNet %s\n",
                       libcfs_nid2str(gateway),
                       libcfs_net2str(LNET_NIDNET(gateway)));
                return -EHOSTUNREACH;
        }

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

        INIT_LIST_HEAD(&rnet->lrn_routes);
        rnet->lrn_net = net;
        /* store the local and remote net that the route represents */
        route->lr_lnet = LNET_NIDNET(gateway);
        route->lr_net = net;
        route->lr_nid = gateway;
        route->lr_priority = priority;
        route->lr_hops = hops;

        lnet_net_lock(LNET_LOCK_EX);

        /*
         * lnet_nid2peerni_ex() grabs a ref on the lpni. We will need to
         * lose that once we're done
         */
        lpni = lnet_nid2peerni_ex(gateway, LNET_LOCK_EX);
        if (IS_ERR(lpni)) {
                lnet_net_unlock(LNET_LOCK_EX);

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

                rc = PTR_ERR(lpni);
                CERROR("Error %d creating route %s %d %s\n", rc,
                        libcfs_net2str(net), hops,
                        libcfs_nid2str(gateway));
                return rc;
        }

        LASSERT(lpni->lpni_peer_net && lpni->lpni_peer_net->lpn_peer);
        gw = lpni->lpni_peer_net->lpn_peer;

        route->lr_gateway = gw;

        rnet2 = lnet_find_rnet_locked(net);
        if (rnet2 == NULL) {
                /* 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(route_entry, &rnet2->lrn_routes) {
                struct lnet_route *route2;

                route2 = list_entry(route_entry, 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_primary_nid != gateway);
        }

        /*
         * It is possible to add multiple routes through the same peer,
         * but it'll be using a different NID of that peer. When the
         * gateway is discovered, discovery will consolidate the different
         * peers into one peer. In this case the discovery code will have
         * to move the routes from the peer that's being deleted to the
         * consolidated peer lp_routes list
         */
        if (add_route) {
                gw->lp_health_sensitivity = sensitivity;
                lnet_add_route_to_rnet(rnet2, route);
                if (lnet_peer_discovery_disabled)
                        CWARN("Consider turning discovery on to enable full "
                              "Multi-Rail routing functionality\n");
        }

        /*
         * get rid of the reference on the lpni.
         */
        lnet_peer_ni_decref_locked(lpni);
        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));

        /* kick start the monitor thread to handle the added route */
        complete(&the_lnet.ln_mt_wait_complete);

        return rc;
}

static void
lnet_del_route_from_rnet(lnet_nid_t gw_nid, struct list_head *route_list,
                         struct list_head *zombies)
{
        struct lnet_peer *gateway;
        struct lnet_route *route;
        struct lnet_route *tmp;

        list_for_each_entry_safe(route, tmp, route_list, lr_list) {
                gateway = route->lr_gateway;
                if (gw_nid != LNET_NID_ANY &&
                    gw_nid != gateway->lp_primary_nid)
                        continue;

                /*
                 * move to zombie to delete outside the lock
                 * Note that this function is called with the
                 * ln_api_mutex held as well as the exclusive net
                 * lock. Adding to the remote net list happens
                 * under the same conditions. Same goes for the
                 * gateway router list
                 */
                list_move(&route->lr_list, zombies);
                the_lnet.ln_remote_nets_version++;

                list_del(&route->lr_gwlist);
                lnet_rtr_decref_locked(gateway);
        }
}

int
lnet_del_route(__u32 net, lnet_nid_t gw_nid)
{
        struct list_head rnet_zombies;
        struct lnet_remotenet *rnet;
        struct lnet_remotenet *tmp;
        struct list_head *rn_list;
        struct lnet_peer_ni *lpni;
        struct lnet_route *route;
        struct list_head zombies;
        struct lnet_peer *lp = NULL;
        int i = 0;

        INIT_LIST_HEAD(&rnet_zombies);
        INIT_LIST_HEAD(&zombies);

        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);

        lpni = lnet_find_peer_ni_locked(gw_nid);
        if (lpni) {
                lp = lpni->lpni_peer_net->lpn_peer;
                LASSERT(lp);
                gw_nid = lp->lp_primary_nid;
                lnet_peer_ni_decref_locked(lpni);
        }

        if (net != LNET_NIDNET(LNET_NID_ANY)) {
                rnet = lnet_find_rnet_locked(net);
                if (!rnet) {
                        lnet_net_unlock(LNET_LOCK_EX);
                        return -ENOENT;
                }
                lnet_del_route_from_rnet(gw_nid, &rnet->lrn_routes,
                                         &zombies);
                if (list_empty(&rnet->lrn_routes))
                        list_move(&rnet->lrn_list, &rnet_zombies);
                goto delete_zombies;
        }

        for (i = 0; i < LNET_REMOTE_NETS_HASH_SIZE; i++) {
                rn_list = &the_lnet.ln_remote_nets_hash[i];

                list_for_each_entry_safe(rnet, tmp, rn_list, lrn_list) {
                        lnet_del_route_from_rnet(gw_nid, &rnet->lrn_routes,
                                                 &zombies);
                        if (list_empty(&rnet->lrn_routes))
                                list_move(&rnet->lrn_list, &rnet_zombies);
                }
        }

delete_zombies:
        /*
         * check if there are any routes remaining on the gateway
         * If there are no more routes make sure to set the peer's
         * lp_disc_net_id to 0 (invalid), in case we add more routes in
         * the future on that gateway, then we start our discovery process
         * from scratch
         */
        if (lpni) {
                if (list_empty(&lp->lp_routes))
                        lp->lp_disc_net_id = 0;
        }

        lnet_net_unlock(LNET_LOCK_EX);

        while (!list_empty(&zombies)) {
                route = list_first_entry(&zombies, struct lnet_route, lr_list);
                list_del(&route->lr_list);
                LIBCFS_FREE(route, sizeof(*route));
        }

        while (!list_empty(&rnet_zombies)) {
                rnet = list_first_entry(&rnet_zombies, struct lnet_remotenet,
                                        lrn_list);
                list_del(&rnet->lrn_list);
                LIBCFS_FREE(rnet, sizeof(*rnet));
        }

        return 0;
}

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

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

        if (the_lnet.ln_rtrpools == NULL)
                return rc;


        cfs_percpt_for_each(rbp, i, the_lnet.ln_rtrpools) {
                if (i != cpt)
                        continue;

                lnet_net_lock(i);
                for (j = 0; j < LNET_NRBPOOLS; j++) {
                        pool_cfg->pl_pools[j].pl_npages = rbp[j].rbp_npages;
                        pool_cfg->pl_pools[j].pl_nbuffers = rbp[j].rbp_nbuffers;
                        pool_cfg->pl_pools[j].pl_credits = rbp[j].rbp_credits;
                        pool_cfg->pl_pools[j].pl_mincredits = rbp[j].rbp_mincredits;
                }
                lnet_net_unlock(i);
                rc = 0;
                break;
        }

        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, __u32 *sensitivity)
{
        struct lnet_remotenet *rnet;
        struct list_head *rn_list;
        struct lnet_route *route;
        struct list_head *e1;
        struct list_head *e2;
        int cpt;
        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);

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

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

        lnet_net_unlock(cpt);
        return -ENOENT;
}

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

        LASSERT(the_lnet.ln_mt_state == LNET_MT_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);

                        spin_lock(&rtr->lp_lock);

                        if ((rtr->lp_state & LNET_PEER_RTR_DISCOVERED) == 0) {
                                all_known = 0;
                                spin_unlock(&rtr->lp_lock);
                                break;
                        }
                        spin_unlock(&rtr->lp_lock);
                }

                lnet_net_unlock(cpt);

                if (all_known)
                        return;

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

static inline bool
lnet_net_set_status_locked(struct lnet_net *net, __u32 status)
{
        struct lnet_ni *ni;
        bool update = false;

        list_for_each_entry(ni, &net->net_ni_list, ni_netlist) {
                lnet_ni_lock(ni);
                if (ni->ni_status &&
                    ni->ni_status->ns_status != status) {
                    ni->ni_status->ns_status = status;
                    update = true;
                }
                lnet_ni_unlock(ni);
        }

        return update;
}

static bool
lnet_update_ni_status_locked(void)
{
        struct lnet_net *net;
        bool push = false;
        time64_t now;
        time64_t timeout;

        LASSERT(the_lnet.ln_routing);

        timeout = router_ping_timeout + alive_router_check_interval;

        now = ktime_get_real_seconds();
        list_for_each_entry(net, &the_lnet.ln_nets, net_list) {
                if (net->net_lnd->lnd_type == LOLND)
                        continue;

                if (now < net->net_last_alive + timeout)
                        continue;

                spin_lock(&net->net_lock);
                /* re-check with lock */
                if (now < net->net_last_alive + timeout) {
                        spin_unlock(&net->net_lock);
                        continue;
                }
                spin_unlock(&net->net_lock);

                /*
                 * if the net didn't receive any traffic for past the
                 * timeout on any of its constituent NIs, then mark all
                 * the NIs down.
                 */
                push = lnet_net_set_status_locked(net, LNET_NI_STATUS_DOWN);
        }

        return push;
}

void lnet_wait_router_start(void)
{
        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();
        }
}

/*
 * This function is called from the monitor thread to check if there are
 * any active routers that need to be checked.
 */
inline bool
lnet_router_checker_active(void)
{
        /* 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) &&
                alive_router_check_interval > 0;
}

void
lnet_check_routers(void)
{
        struct lnet_peer_net *first_lpn = NULL;
        struct lnet_peer_net *lpn;
        struct lnet_peer_ni *lpni;
        struct list_head *entry;
        struct lnet_peer *rtr;
        bool push = false;
        bool found_lpn;
        __u64 version;
        __u32 net_id;
        time64_t now;
        int cpt;
        int rc;

        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);

                now = ktime_get_real_seconds();

                /*
                 * only discover the router if we've passed
                 * alive_router_check_interval seconds. Some of the router
                 * interfaces could be down and in that case they would be
                 * undergoing recovery separately from this discovery.
                 */
                /* find next peer net which is also local */
                net_id = rtr->lp_disc_net_id;
                do {
                        lpn = lnet_get_next_peer_net_locked(rtr, net_id);
                        if (!lpn) {
                                CERROR("gateway %s has no networks\n",
                                libcfs_nid2str(rtr->lp_primary_nid));
                                break;
                        }
                        if (first_lpn == lpn)
                                break;
                        if (!first_lpn)
                                first_lpn = lpn;
                        found_lpn = lnet_islocalnet_locked(lpn->lpn_net_id);
                        net_id = lpn->lpn_net_id;
                } while (!found_lpn);

                if (!found_lpn || !lpn) {
                        CERROR("no local network found for gateway %s\n",
                               libcfs_nid2str(rtr->lp_primary_nid));
                        continue;
                }

                if (now - lpn->lpn_rtrcheck_timestamp <
                    alive_router_check_interval / lnet_current_net_count)
                       continue;

                /*
                 * If we're currently discovering the peer then don't
                 * issue another discovery
                 */
                spin_lock(&rtr->lp_lock);
                if (rtr->lp_state & LNET_PEER_RTR_DISCOVERY) {
                        spin_unlock(&rtr->lp_lock);
                        continue;
                }
                /* make sure we actively discover the router */
                rtr->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
                rtr->lp_state |= LNET_PEER_RTR_DISCOVERY;
                spin_unlock(&rtr->lp_lock);

                /* find the peer_ni associated with the primary NID */
                lpni = lnet_peer_get_ni_locked(rtr, rtr->lp_primary_nid);
                if (!lpni) {
                        CDEBUG(D_NET, "Expected to find an lpni for %s, but non found\n",
                               libcfs_nid2str(rtr->lp_primary_nid));
                        continue;
                }
                lnet_peer_ni_addref_locked(lpni);

                /* specify the net to use */
                rtr->lp_disc_net_id = lpn->lpn_net_id;

                /* discover the router */
                CDEBUG(D_NET, "discover %s, cpt = %d\n",
                       libcfs_nid2str(lpni->lpni_nid), cpt);
                rc = lnet_discover_peer_locked(lpni, cpt, false);

                /* decrement ref count acquired by find_peer_ni_locked() */
                lnet_peer_ni_decref_locked(lpni);

                if (!rc)
                        lpn->lpn_rtrcheck_timestamp = now;
                else
                        CERROR("Failed to discover router %s\n",
                               libcfs_nid2str(rtr->lp_primary_nid));

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

        if (the_lnet.ln_routing)
                push = lnet_update_ni_status_locked();

        lnet_net_unlock(cpt);

        /* if the status of the ni changed update the peers */
        if (push)
                lnet_push_update_to_peers(1);
}

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].kiov_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 == NULL)
                return NULL;

        rb->rb_pool = rbp;

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

                        LIBCFS_FREE(rb, sz);
                        return NULL;
                }

                rb->rb_kiov[i].kiov_len = PAGE_SIZE;
                rb->rb_kiov[i].kiov_offset = 0;
                rb->rb_kiov[i].kiov_page = page;
        }

        return rb;
}

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

        if (rbp->rbp_nbuffers == 0) /* not initialized or already freed */
                return;

        INIT_LIST_HEAD(&tmp);

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

        /* Free buffers on the free list. */
        while (!list_empty(&tmp)) {
                rb = list_entry(tmp.next, struct lnet_rtrbuf, 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 == NULL) {
                        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 == NULL) /* 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 == NULL) {
                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 != 0)
                        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 != 0)
                        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 != 0)
                        goto failed;
        }

        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_routing = 1;
        lnet_net_unlock(LNET_LOCK_EX);
        complete(&the_lnet.ln_mt_wait_complete);
        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 != 0)
                                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 != 0)
                                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 != 0)
                                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 == NULL)
                /* 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 != 0)
                return rc;

        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_routing = 1;

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

        if (lnet_peer_discovery_disabled)
                CWARN("Consider turning discovery on to enable full "
                      "Multi-Rail routing functionality\n");

        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_target->pb_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);
}

static inline void
lnet_notify_peer_down(struct lnet_ni *ni, lnet_nid_t nid)
{
        if (ni->ni_net->net_lnd->lnd_notify_peer_down != NULL)
                (ni->ni_net->net_lnd->lnd_notify_peer_down)(nid);
}

/*
 * ni: local NI used to communicate with the peer
 * nid: peer NID
 * alive: true if peer is alive, false otherwise
 * reset: reset health value. This is requested by the LND.
 * when: notificaiton time.
 */
int
lnet_notify(struct lnet_ni *ni, lnet_nid_t nid, bool alive, bool reset,
            time64_t when)
{
        struct lnet_peer_ni *lpni = NULL;
        struct lnet_route *route;
        struct lnet_peer *lp;
        time64_t now = ktime_get_seconds();
        int cpt;

        LASSERT (!in_interrupt ());

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

        if (ni != NULL &&
            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 (when > now) {
                CWARN("Ignoring prediction from %s of %s %s "
                      "%lld seconds in the future\n",
                      (ni == NULL) ? "userspace" : libcfs_nid2str(ni->ni_nid),
                      libcfs_nid2str(nid), alive ? "up" : "down", when - now);
                return -EINVAL;
        }

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

        /* must lock 0 since this is used for synchronization */
        lnet_net_lock(0);

        if (the_lnet.ln_state != LNET_STATE_RUNNING) {
                lnet_net_unlock(0);
                return -ESHUTDOWN;
        }

        lpni = lnet_find_peer_ni_locked(nid);
        if (lpni == NULL) {
                /* nid not found */
                lnet_net_unlock(0);
                CDEBUG(D_NET, "%s not found\n", libcfs_nid2str(nid));
                return 0;
        }

        if (alive) {
                if (reset)
                        lnet_set_healthv(&lpni->lpni_healthv,
                                         LNET_MAX_HEALTH_VALUE);
                else
                        lnet_inc_healthv(&lpni->lpni_healthv);
        } else {
                lnet_handle_remote_failure_locked(lpni);
        }

        /* recalculate aliveness */
        alive = lnet_is_peer_ni_alive(lpni);
        lnet_net_unlock(0);

        if (ni != NULL && !alive)
                lnet_notify_peer_down(ni, lpni->lpni_nid);

        cpt = lpni->lpni_cpt;
        lnet_net_lock(cpt);
        lnet_peer_ni_decref_locked(lpni);
        if (lpni && lpni->lpni_peer_net && lpni->lpni_peer_net->lpn_peer) {
                lp = lpni->lpni_peer_net->lpn_peer;
                list_for_each_entry(route, &lp->lp_routes, lr_gwlist)
                        lnet_set_route_aliveness(route, alive);
        }
        lnet_net_unlock(cpt);

        return 0;
}
EXPORT_SYMBOL(lnet_notify);