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LU-12756 lnet: Remove unnecessary rtr_nid argument
[fs/lustre-release.git] / lnet / lnet / lib-move.c
index 1706ef7..07dc2d3 100644 (file)
@@ -42,8 +42,6 @@
 #include <linux/nsproxy.h>
 #include <net/net_namespace.h>
 
-extern unsigned int lnet_current_net_count;
-
 static int local_nid_dist_zero = 1;
 module_param(local_nid_dist_zero, int, 0444);
 MODULE_PARM_DESC(local_nid_dist_zero, "Reserved");
@@ -65,6 +63,12 @@ struct lnet_send_data {
        __u32 sd_send_case;
 };
 
+static inline bool
+lnet_msg_is_response(struct lnet_msg *msg)
+{
+       return msg->msg_type == LNET_MSG_ACK || msg->msg_type == LNET_MSG_REPLY;
+}
+
 static inline struct lnet_comm_count *
 get_stats_counts(struct lnet_element_stats *stats,
                 enum lnet_stats_type stats_type)
@@ -167,7 +171,7 @@ lnet_fail_nid(lnet_nid_t nid, unsigned int threshold)
        struct lnet_test_peer *tp;
        struct list_head *el;
        struct list_head *next;
-       struct list_head  cull;
+       LIST_HEAD(cull);
 
        /* NB: use lnet_net_lock(0) to serialize operations on test peers */
        if (threshold != 0) {
@@ -185,9 +189,6 @@ lnet_fail_nid(lnet_nid_t nid, unsigned int threshold)
                return 0;
        }
 
-       /* removing entries */
-       INIT_LIST_HEAD(&cull);
-
        lnet_net_lock(0);
 
        list_for_each_safe(el, next, &the_lnet.ln_test_peers) {
@@ -196,8 +197,7 @@ lnet_fail_nid(lnet_nid_t nid, unsigned int threshold)
                if (tp->tp_threshold == 0 ||    /* needs culling anyway */
                    nid == LNET_NID_ANY ||      /* removing all entries */
                    tp->tp_nid == nid) {        /* matched this one */
-                       list_del(&tp->tp_list);
-                       list_add(&tp->tp_list, &cull);
+                       list_move(&tp->tp_list, &cull);
                }
        }
 
@@ -218,10 +218,8 @@ fail_peer (lnet_nid_t nid, int outgoing)
        struct lnet_test_peer *tp;
        struct list_head *el;
        struct list_head *next;
-       struct list_head  cull;
-       int               fail = 0;
-
-       INIT_LIST_HEAD(&cull);
+       LIST_HEAD(cull);
+       int fail = 0;
 
        /* NB: use lnet_net_lock(0) to serialize operations on test peers */
        lnet_net_lock(0);
@@ -235,8 +233,7 @@ fail_peer (lnet_nid_t nid, int outgoing)
                                /* only cull zombies on outgoing tests,
                                 * since we may be at interrupt priority on
                                 * incoming messages. */
-                               list_del(&tp->tp_list);
-                               list_add(&tp->tp_list, &cull);
+                               list_move(&tp->tp_list, &cull);
                        }
                        continue;
                }
@@ -250,8 +247,7 @@ fail_peer (lnet_nid_t nid, int outgoing)
                                if (outgoing &&
                                    tp->tp_threshold == 0) {
                                        /* see above */
-                                       list_del(&tp->tp_list);
-                                       list_add(&tp->tp_list, &cull);
+                                       list_move(&tp->tp_list, &cull);
                                }
                        }
                        break;
@@ -289,7 +285,7 @@ lnet_copy_iov2iov(unsigned int ndiov, struct kvec *diov, unsigned int doffset,
                  unsigned int nob)
 {
        /* NB diov, siov are READ-ONLY */
-       unsigned int  this_nob;
+       unsigned int this_nob;
 
        if (nob == 0)
                return;
@@ -315,9 +311,9 @@ lnet_copy_iov2iov(unsigned int ndiov, struct kvec *diov, unsigned int doffset,
        do {
                LASSERT(ndiov > 0);
                LASSERT(nsiov > 0);
-               this_nob = MIN(diov->iov_len - doffset,
-                              siov->iov_len - soffset);
-               this_nob = MIN(this_nob, nob);
+               this_nob = min3((unsigned int)diov->iov_len - doffset,
+                               (unsigned int)siov->iov_len - soffset,
+                               nob);
 
                memcpy((char *)diov->iov_base + doffset,
                       (char *)siov->iov_base + soffset, this_nob);
@@ -437,9 +433,9 @@ lnet_copy_kiov2kiov(unsigned int ndiov, lnet_kiov_t *diov, unsigned int doffset,
        do {
                LASSERT(ndiov > 0);
                LASSERT(nsiov > 0);
-               this_nob = MIN(diov->kiov_len - doffset,
-                              siov->kiov_len - soffset);
-               this_nob = MIN(this_nob, nob);
+               this_nob = min3(diov->kiov_len - doffset,
+                               siov->kiov_len - soffset,
+                               nob);
 
                if (daddr == NULL)
                        daddr = ((char *)kmap(diov->kiov_page)) +
@@ -518,9 +514,9 @@ lnet_copy_kiov2iov (unsigned int niov, struct kvec *iov, unsigned int iovoffset,
        do {
                LASSERT(niov > 0);
                LASSERT(nkiov > 0);
-               this_nob = MIN(iov->iov_len - iovoffset,
-                              kiov->kiov_len - kiovoffset);
-               this_nob = MIN(this_nob, nob);
+               this_nob = min3((unsigned int)iov->iov_len - iovoffset,
+                               (unsigned int)kiov->kiov_len - kiovoffset,
+                               nob);
 
                if (addr == NULL)
                        addr = ((char *)kmap(kiov->kiov_page)) +
@@ -588,9 +584,9 @@ lnet_copy_iov2kiov(unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffse
        do {
                LASSERT(nkiov > 0);
                LASSERT(niov > 0);
-               this_nob = MIN(kiov->kiov_len - kiovoffset,
-                              iov->iov_len - iovoffset);
-               this_nob = MIN(this_nob, nob);
+               this_nob = min3((unsigned int)kiov->kiov_len - kiovoffset,
+                               (unsigned int)iov->iov_len - iovoffset,
+                               nob);
 
                if (addr == NULL)
                        addr = ((char *)kmap(kiov->kiov_page)) +
@@ -837,8 +833,7 @@ lnet_peer_alive_locked(struct lnet_ni *ni, struct lnet_peer_ni *lpni,
                return 1;
 
        /* always send any responses */
-       if (msg->msg_type == LNET_MSG_ACK ||
-           msg->msg_type == LNET_MSG_REPLY)
+       if (lnet_msg_is_response(msg))
                return 1;
 
        if (!lnet_is_peer_deadline_passed(lpni, now))
@@ -1274,8 +1269,7 @@ routing_off:
                /* drop all messages which are queued to be routed on that
                 * peer. */
                if (!the_lnet.ln_routing) {
-                       struct list_head drop;
-                       INIT_LIST_HEAD(&drop);
+                       LIST_HEAD(drop);
                        list_splice_init(&lp->lp_rtrq, &drop);
                        spin_unlock(&lp->lp_lock);
                        spin_unlock(&rxpeerni->lpni_lock);
@@ -1320,7 +1314,7 @@ routing_off:
 }
 
 static int
-lnet_compare_peers(struct lnet_peer_ni *p1, struct lnet_peer_ni *p2)
+lnet_compare_gw_lpnis(struct lnet_peer_ni *p1, struct lnet_peer_ni *p2)
 {
        if (p1->lpni_txqnob < p2->lpni_txqnob)
                return 1;
@@ -1437,8 +1431,8 @@ lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
  * Prerequisite: the best_ni should already be set in the sd
  */
 static inline struct lnet_peer_ni *
-lnet_find_best_lpni_on_net(struct lnet_send_data *sd, struct lnet_peer *peer,
-                          __u32 net_id)
+lnet_find_best_lpni_on_net(struct lnet_ni *lni, lnet_nid_t dst_nid,
+                          struct lnet_peer *peer, __u32 net_id)
 {
        struct lnet_peer_net *peer_net;
 
@@ -1455,111 +1449,101 @@ lnet_find_best_lpni_on_net(struct lnet_send_data *sd, struct lnet_peer *peer,
                return NULL;
        }
 
-       return lnet_select_peer_ni(sd->sd_best_ni, sd->sd_dst_nid,
-                                  peer, peer_net);
+       return lnet_select_peer_ni(lni, dst_nid, peer, peer_net);
 }
 
+/* Compare route priorities and hop counts */
 static int
-lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2,
-                   struct lnet_peer_ni **best_lpni)
+lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2)
 {
        int r1_hops = (r1->lr_hops == LNET_UNDEFINED_HOPS) ? 1 : r1->lr_hops;
        int r2_hops = (r2->lr_hops == LNET_UNDEFINED_HOPS) ? 1 : r2->lr_hops;
-       struct lnet_peer *lp1 = r1->lr_gateway;
-       struct lnet_peer *lp2 = r2->lr_gateway;
-       struct lnet_peer_ni *lpni1;
-       struct lnet_peer_ni *lpni2;
-       struct lnet_send_data sd;
-       int rc;
 
-       sd.sd_best_ni = NULL;
-       sd.sd_dst_nid = LNET_NID_ANY;
-       lpni1 = lnet_find_best_lpni_on_net(&sd, lp1, r1->lr_lnet);
-       lpni2 = lnet_find_best_lpni_on_net(&sd, lp2, r2->lr_lnet);
-       LASSERT(lpni1 && lpni2);
-
-       if (r1->lr_priority < r2->lr_priority) {
-               *best_lpni = lpni1;
+       if (r1->lr_priority < r2->lr_priority)
                return 1;
-       }
 
-       if (r1->lr_priority > r2->lr_priority) {
-               *best_lpni = lpni2;
+       if (r1->lr_priority > r2->lr_priority)
                return -1;
-       }
 
-       if (r1_hops < r2_hops) {
-               *best_lpni = lpni1;
+       if (r1_hops < r2_hops)
                return 1;
-       }
 
-       if (r1_hops > r2_hops) {
-               *best_lpni = lpni2;
+       if (r1_hops > r2_hops)
                return -1;
-       }
-
-       rc = lnet_compare_peers(lpni1, lpni2);
-       if (rc == 1) {
-               *best_lpni = lpni1;
-               return rc;
-       } else if (rc == -1) {
-               *best_lpni = lpni2;
-               return rc;
-       }
 
-       if (r1->lr_seq - r2->lr_seq <= 0) {
-               *best_lpni = lpni1;
-               return 1;
-       }
-
-       *best_lpni = lpni2;
-       return -1;
+       return 0;
 }
 
 static struct lnet_route *
-lnet_find_route_locked(struct lnet_net *net, __u32 remote_net,
-                      lnet_nid_t rtr_nid, struct lnet_route **prev_route,
+lnet_find_route_locked(struct lnet_remotenet *rnet, __u32 src_net,
+                      struct lnet_route **prev_route,
                       struct lnet_peer_ni **gwni)
 {
-       struct lnet_peer_ni *best_gw_ni = NULL;
+       struct lnet_peer_ni *lpni, *best_gw_ni = NULL;
        struct lnet_route *best_route;
        struct lnet_route *last_route;
-       struct lnet_remotenet *rnet;
-       struct lnet_peer *lp_best;
        struct lnet_route *route;
-       struct lnet_peer *lp;
        int rc;
+       __u32 restrict_net;
+       __u32 any_net = LNET_NIDNET(LNET_NID_ANY);
 
-       /* If @rtr_nid is not LNET_NID_ANY, return the gateway with
-        * rtr_nid nid, otherwise find the best gateway I can use */
-
-       rnet = lnet_find_rnet_locked(remote_net);
-       if (rnet == NULL)
-               return NULL;
-
-       lp_best = NULL;
        best_route = last_route = NULL;
        list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
-               lp = route->lr_gateway;
-
                if (!lnet_is_route_alive(route))
                        continue;
 
-               if (lp_best == NULL) {
-                       best_route = last_route = route;
-                       lp_best = lp;
+               /* If the src_net is specified then we need to find an lpni
+                * on that network
+                */
+               restrict_net = src_net == any_net ? route->lr_lnet : src_net;
+               if (!best_route) {
+                       lpni = lnet_find_best_lpni_on_net(NULL, LNET_NID_ANY,
+                                                         route->lr_gateway,
+                                                         restrict_net);
+                       if (lpni) {
+                               best_route = last_route = route;
+                               best_gw_ni = lpni;
+                       } else
+                               CERROR("Gateway %s does not have a peer NI on net %s\n",
+                                      libcfs_nid2str(route->lr_gateway->lp_primary_nid),
+                                      libcfs_net2str(restrict_net));
+
+                       continue;
                }
 
                /* no protection on below fields, but it's harmless */
                if (last_route->lr_seq - route->lr_seq < 0)
                        last_route = route;
 
-               rc = lnet_compare_routes(route, best_route, &best_gw_ni);
-               if (rc < 0)
+               rc = lnet_compare_routes(route, best_route);
+               if (rc == -1)
+                       continue;
+
+               lpni = lnet_find_best_lpni_on_net(NULL, LNET_NID_ANY,
+                                                 route->lr_gateway,
+                                                 restrict_net);
+               if (!lpni) {
+                       CERROR("Gateway %s does not have a peer NI on net %s\n",
+                              libcfs_nid2str(route->lr_gateway->lp_primary_nid),
+                              libcfs_net2str(restrict_net));
+                       continue;
+               }
+
+               if (rc == 1) {
+                       best_route = route;
+                       best_gw_ni = lpni;
+                       continue;
+               }
+
+               rc = lnet_compare_gw_lpnis(lpni, best_gw_ni);
+               if (rc == -1)
                        continue;
 
-               best_route = route;
-               lp_best = lp;
+               if (rc == 1 || route->lr_seq <= best_route->lr_seq) {
+                       best_route = route;
+                       best_gw_ni = lpni;
+                       continue;
+               }
        }
 
        *prev_route = last_route;
@@ -1849,30 +1833,28 @@ lnet_handle_send(struct lnet_send_data *sd)
        rc = lnet_post_send_locked(msg, 0);
 
        if (!rc)
-               CDEBUG(D_NET, "TRACE: %s(%s:%s) -> %s(%s:%s) : %s try# %d\n",
+               CDEBUG(D_NET, "TRACE: %s(%s:%s) -> %s(%s:%s) %s : %s try# %d\n",
                       libcfs_nid2str(msg->msg_hdr.src_nid),
                       libcfs_nid2str(msg->msg_txni->ni_nid),
                       libcfs_nid2str(sd->sd_src_nid),
                       libcfs_nid2str(msg->msg_hdr.dest_nid),
                       libcfs_nid2str(sd->sd_dst_nid),
                       libcfs_nid2str(msg->msg_txpeer->lpni_nid),
+                      libcfs_nid2str(sd->sd_rtr_nid),
                       lnet_msgtyp2str(msg->msg_type), msg->msg_retry_count);
 
        return rc;
 }
 
 static inline void
-lnet_set_non_mr_pref_nid(struct lnet_send_data *sd)
+lnet_set_non_mr_pref_nid(struct lnet_peer_ni *lpni, struct lnet_ni *lni,
+                        struct lnet_msg *msg)
 {
-       if (sd->sd_send_case & NMR_DST &&
-           sd->sd_msg->msg_type != LNET_MSG_REPLY &&
-           sd->sd_msg->msg_type != LNET_MSG_ACK &&
-           sd->sd_best_lpni->lpni_pref_nnids == 0) {
+       if (!lnet_msg_is_response(msg) && lpni->lpni_pref_nnids == 0) {
                CDEBUG(D_NET, "Setting preferred local NID %s on NMR peer %s\n",
-                      libcfs_nid2str(sd->sd_best_ni->ni_nid),
-                      libcfs_nid2str(sd->sd_best_lpni->lpni_nid));
-               lnet_peer_ni_set_non_mr_pref_nid(sd->sd_best_lpni,
-                                                sd->sd_best_ni->ni_nid);
+                      libcfs_nid2str(lni->ni_nid),
+                      libcfs_nid2str(lpni->lpni_nid));
+               lnet_peer_ni_set_non_mr_pref_nid(lpni, lni->ni_nid);
        }
 }
 
@@ -1897,10 +1879,7 @@ lnet_handle_spec_local_nmr_dst(struct lnet_send_data *sd)
                return -EINVAL;
        }
 
-       /*
-        * the preferred NID will only be set for NMR peers
-        */
-       lnet_set_non_mr_pref_nid(sd);
+       lnet_set_non_mr_pref_nid(sd->sd_best_lpni, sd->sd_best_ni, sd->sd_msg);
 
        return lnet_handle_send(sd);
 }
@@ -1910,8 +1889,11 @@ lnet_handle_spec_local_nmr_dst(struct lnet_send_data *sd)
  * Local Destination
  * MR Peer
  *
- * Run the selection algorithm on the peer NIs unless we're sending
- * a response, in this case just send to the destination
+ * Don't run the selection algorithm on the peer NIs. By specifying the
+ * local NID, we're also saying that we should always use the destination NID
+ * provided. This handles the case where we should be using the same
+ * destination NID for the all the messages which belong to the same RPC
+ * request.
  */
 static int
 lnet_handle_spec_local_mr_dst(struct lnet_send_data *sd)
@@ -1924,17 +1906,6 @@ lnet_handle_spec_local_mr_dst(struct lnet_send_data *sd)
                return -EINVAL;
        }
 
-       /*
-        * only run the selection algorithm to pick the peer_ni if we're
-        * sending a GET or a PUT. Responses are sent to the same
-        * destination NID provided.
-        */
-       if (!(sd->sd_send_case & SND_RESP)) {
-               sd->sd_best_lpni =
-                 lnet_find_best_lpni_on_net(sd, sd->sd_peer,
-                                            sd->sd_best_ni->ni_net->net_id);
-       }
-
        if (sd->sd_best_lpni &&
            sd->sd_best_lpni->lpni_nid == the_lnet.ln_loni->ni_nid)
                return lnet_handle_lo_send(sd);
@@ -1980,12 +1951,10 @@ lnet_find_best_ni_on_spec_net(struct lnet_ni *cur_best_ni,
 }
 
 static int
-lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni,
-                            struct lnet_msg *msg, lnet_nid_t rtr_nid,
+lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni, struct lnet_msg *msg,
                             int cpt)
 {
        struct lnet_peer *peer;
-       lnet_nid_t primary_nid;
        int rc;
 
        lnet_peer_ni_addref_locked(lpni);
@@ -2009,18 +1978,22 @@ lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni,
        }
        /* The peer may have changed. */
        peer = lpni->lpni_peer_net->lpn_peer;
+       spin_lock(&peer->lp_lock);
+       if (lnet_peer_is_uptodate_locked(peer)) {
+               spin_unlock(&peer->lp_lock);
+               lnet_peer_ni_decref_locked(lpni);
+               return 0;
+       }
        /* queue message and return */
-       msg->msg_rtr_nid_param = rtr_nid;
        msg->msg_sending = 0;
        msg->msg_txpeer = NULL;
-       spin_lock(&peer->lp_lock);
        list_add_tail(&msg->msg_list, &peer->lp_dc_pendq);
        spin_unlock(&peer->lp_lock);
+
        lnet_peer_ni_decref_locked(lpni);
-       primary_nid = peer->lp_primary_nid;
 
        CDEBUG(D_NET, "msg %p delayed. %s pending discovery\n",
-               msg, libcfs_nid2str(primary_nid));
+              msg, libcfs_nid2str(peer->lp_primary_nid));
 
        return LNET_DC_WAIT;
 }
@@ -2032,91 +2005,117 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
                             struct lnet_peer **gw_peer)
 {
        int rc;
+       __u32 local_lnet;
        struct lnet_peer *gw;
        struct lnet_peer *lp;
        struct lnet_peer_net *lpn;
        struct lnet_peer_net *best_lpn = NULL;
-       struct lnet_remotenet *rnet;
-       struct lnet_route *best_route;
-       struct lnet_route *last_route;
+       struct lnet_remotenet *rnet, *best_rnet = NULL;
+       struct lnet_route *best_route = NULL;
+       struct lnet_route *last_route = NULL;
        struct lnet_peer_ni *lpni = NULL;
        struct lnet_peer_ni *gwni = NULL;
        lnet_nid_t src_nid = sd->sd_src_nid;
 
-       /* we've already looked up the initial lpni using dst_nid */
-       lpni = sd->sd_best_lpni;
-       /* the peer tree must be in existence */
-       LASSERT(lpni && lpni->lpni_peer_net && lpni->lpni_peer_net->lpn_peer);
-       lp = lpni->lpni_peer_net->lpn_peer;
+       /* If a router nid was specified then we are replying to a GET or
+        * sending an ACK. In this case we use the gateway associated with the
+        * specified router nid.
+        */
+       if (sd->sd_rtr_nid != LNET_NID_ANY) {
+               gwni = lnet_find_peer_ni_locked(sd->sd_rtr_nid);
+               if (!gwni) {
+                       CERROR("No peer NI for gateway %s\n",
+                              libcfs_nid2str(sd->sd_rtr_nid));
+                       return -EHOSTUNREACH;
+               }
+               gw = gwni->lpni_peer_net->lpn_peer;
+               lnet_peer_ni_decref_locked(gwni);
+               local_lnet = LNET_NIDNET(sd->sd_rtr_nid);
+       } else {
+               /* we've already looked up the initial lpni using dst_nid */
+               lpni = sd->sd_best_lpni;
+               /* the peer tree must be in existence */
+               LASSERT(lpni && lpni->lpni_peer_net &&
+                       lpni->lpni_peer_net->lpn_peer);
+               lp = lpni->lpni_peer_net->lpn_peer;
+
+               list_for_each_entry(lpn, &lp->lp_peer_nets, lpn_peer_nets) {
+                       /* is this remote network reachable?  */
+                       rnet = lnet_find_rnet_locked(lpn->lpn_net_id);
+                       if (!rnet)
+                               continue;
 
-       list_for_each_entry(lpn, &lp->lp_peer_nets, lpn_peer_nets) {
-               /* is this remote network reachable?  */
-               rnet = lnet_find_rnet_locked(lpn->lpn_net_id);
-               if (!rnet)
-                       continue;
+                       if (!best_lpn) {
+                               best_lpn = lpn;
+                               best_rnet = rnet;
+                       }
+
+                       if (best_lpn->lpn_seq <= lpn->lpn_seq)
+                               continue;
 
-               if (!best_lpn)
                        best_lpn = lpn;
+                       best_rnet = rnet;
+               }
 
-               if (best_lpn->lpn_seq <= lpn->lpn_seq)
-                       continue;
+               if (!best_lpn) {
+                       CERROR("peer %s has no available nets\n",
+                              libcfs_nid2str(sd->sd_dst_nid));
+                       return -EHOSTUNREACH;
+               }
 
-               best_lpn = lpn;
-       }
+               sd->sd_best_lpni = lnet_find_best_lpni_on_net(sd->sd_best_ni,
+                                                             sd->sd_dst_nid,
+                                                             lp,
+                                                             best_lpn->lpn_net_id);
+               if (!sd->sd_best_lpni) {
+                       CERROR("peer %s down\n",
+                              libcfs_nid2str(sd->sd_dst_nid));
+                       return -EHOSTUNREACH;
+               }
 
-       if (!best_lpn) {
-               CERROR("peer %s has no available nets \n",
-                      libcfs_nid2str(sd->sd_dst_nid));
-               return -EHOSTUNREACH;
-       }
+               best_route = lnet_find_route_locked(best_rnet,
+                                                   LNET_NIDNET(src_nid),
+                                                   &last_route, &gwni);
+               if (!best_route) {
+                       CERROR("no route to %s from %s\n",
+                              libcfs_nid2str(dst_nid),
+                              libcfs_nid2str(src_nid));
+                       return -EHOSTUNREACH;
+               }
 
-       sd->sd_best_lpni = lnet_find_best_lpni_on_net(sd, lp, best_lpn->lpn_net_id);
-       if (!sd->sd_best_lpni) {
-               CERROR("peer %s down\n", libcfs_nid2str(sd->sd_dst_nid));
-               return -EHOSTUNREACH;
-       }
+               if (!gwni) {
+                       CERROR("Internal Error. Route expected to %s from %s\n",
+                              libcfs_nid2str(dst_nid),
+                              libcfs_nid2str(src_nid));
+                       return -EFAULT;
+               }
 
-       best_route = lnet_find_route_locked(NULL, best_lpn->lpn_net_id,
-                                           sd->sd_rtr_nid, &last_route,
-                                           &gwni);
-       if (!best_route) {
-               CERROR("no route to %s from %s\n",
-                      libcfs_nid2str(dst_nid), libcfs_nid2str(src_nid));
-               return -EHOSTUNREACH;
-       }
+               gw = best_route->lr_gateway;
+               LASSERT(gw == gwni->lpni_peer_net->lpn_peer);
+               local_lnet = best_route->lr_lnet;
 
-       if (!gwni) {
-               CERROR("Internal Error. Route expected to %s from %s\n",
-                       libcfs_nid2str(dst_nid),
-                       libcfs_nid2str(src_nid));
-               return -EFAULT;
        }
 
-       gw = best_route->lr_gateway;
-       LASSERT(gw == gwni->lpni_peer_net->lpn_peer);
-
        /*
         * Discover this gateway if it hasn't already been discovered.
         * This means we might delay the message until discovery has
         * completed
         */
        sd->sd_msg->msg_src_nid_param = sd->sd_src_nid;
-       rc = lnet_initiate_peer_discovery(gwni, sd->sd_msg, sd->sd_rtr_nid,
-                                         sd->sd_cpt);
+       rc = lnet_initiate_peer_discovery(gwni, sd->sd_msg, sd->sd_cpt);
        if (rc)
                return rc;
 
        if (!sd->sd_best_ni)
                sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL, gw,
                                        lnet_peer_get_net_locked(gw,
-                                               best_route->lr_lnet),
+                                                                local_lnet),
                                        sd->sd_md_cpt,
                                        true);
 
        if (!sd->sd_best_ni) {
-               CERROR("Internal Error. Expected local ni on %s "
-                      "but non found :%s\n",
-                      libcfs_net2str(best_route->lr_lnet),
+               CERROR("Internal Error. Expected local ni on %s but non found :%s\n",
+                      libcfs_net2str(local_lnet),
                       libcfs_nid2str(sd->sd_src_nid));
                return -EFAULT;
        }
@@ -2128,9 +2127,11 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
         * increment the sequence numbers since now we're sure we're
         * going to use this path
         */
-       LASSERT(best_route && last_route);
-       best_route->lr_seq = last_route->lr_seq + 1;
-       best_lpn->lpn_seq++;
+       if (sd->sd_rtr_nid == LNET_NID_ANY) {
+               LASSERT(best_route && last_route);
+               best_route->lr_seq = last_route->lr_seq + 1;
+               best_lpn->lpn_seq++;
+       }
 
        return 0;
 }
@@ -2174,10 +2175,11 @@ lnet_handle_spec_router_dst(struct lnet_send_data *sd)
 
        if (sd->sd_send_case & NMR_DST)
                /*
-               * since the final destination is non-MR let's set its preferred
-               * NID before we send
-               */
-               lnet_set_non_mr_pref_nid(sd);
+                * since the final destination is non-MR let's set its preferred
+                * NID before we send
+                */
+               lnet_set_non_mr_pref_nid(sd->sd_best_lpni, sd->sd_best_ni,
+                                        sd->sd_msg);
 
        /*
         * We're going to send to the gw found so let's set its
@@ -2231,14 +2233,11 @@ lnet_find_best_ni_on_local_net(struct lnet_peer *peer, int md_cpt,
 }
 
 static struct lnet_ni *
-lnet_find_existing_preferred_best_ni(struct lnet_send_data *sd)
+lnet_find_existing_preferred_best_ni(struct lnet_peer_ni *lpni, int cpt)
 {
        struct lnet_ni *best_ni = NULL;
-       struct lnet_peer_net *peer_net;
-       struct lnet_peer *peer = sd->sd_peer;
-       struct lnet_peer_ni *best_lpni = sd->sd_best_lpni;
-       struct lnet_peer_ni *lpni;
-       int cpt = sd->sd_cpt;
+       struct lnet_peer_net *peer_net = lpni->lpni_peer_net;
+       struct lnet_peer_ni *lpni_entry;
 
        /*
         * We must use a consistent source address when sending to a
@@ -2250,18 +2249,13 @@ lnet_find_existing_preferred_best_ni(struct lnet_send_data *sd)
         * So we need to pick the NI the peer prefers for this
         * particular network.
         */
-
-       /* Get the target peer_ni */
-       peer_net = lnet_peer_get_net_locked(peer,
-                       LNET_NIDNET(best_lpni->lpni_nid));
-       LASSERT(peer_net != NULL);
-       list_for_each_entry(lpni, &peer_net->lpn_peer_nis,
-                               lpni_peer_nis) {
-               if (lpni->lpni_pref_nnids == 0)
+       LASSERT(peer_net);
+       list_for_each_entry(lpni_entry, &peer_net->lpn_peer_nis,
+                           lpni_peer_nis) {
+               if (lpni_entry->lpni_pref_nnids == 0)
                        continue;
-               LASSERT(lpni->lpni_pref_nnids == 1);
-               best_ni = lnet_nid2ni_locked(
-                               lpni->lpni_pref.nid, cpt);
+               LASSERT(lpni_entry->lpni_pref_nnids == 1);
+               best_ni = lnet_nid2ni_locked(lpni_entry->lpni_pref.nid, cpt);
                break;
        }
 
@@ -2286,7 +2280,8 @@ lnet_select_preferred_best_ni(struct lnet_send_data *sd)
         * particular network.
         */
 
-       best_ni = lnet_find_existing_preferred_best_ni(sd);
+       best_ni = lnet_find_existing_preferred_best_ni(sd->sd_best_lpni,
+                                                      sd->sd_cpt);
 
        /* if best_ni is still not set just pick one */
        if (!best_ni) {
@@ -2306,7 +2301,7 @@ lnet_select_preferred_best_ni(struct lnet_send_data *sd)
        sd->sd_best_ni = best_ni;
 
        /* Set preferred NI if necessary. */
-       lnet_set_non_mr_pref_nid(sd);
+       lnet_set_non_mr_pref_nid(sd->sd_best_lpni, sd->sd_best_ni, sd->sd_msg);
 
        return 0;
 }
@@ -2394,7 +2389,8 @@ lnet_handle_any_mr_dsta(struct lnet_send_data *sd)
                                        lnet_msg_discovery(sd->sd_msg));
        if (sd->sd_best_ni) {
                sd->sd_best_lpni =
-                 lnet_find_best_lpni_on_net(sd, sd->sd_peer,
+                 lnet_find_best_lpni_on_net(sd->sd_best_ni, sd->sd_dst_nid,
+                                            sd->sd_peer,
                                             sd->sd_best_ni->ni_net->net_id);
 
                /*
@@ -2538,9 +2534,10 @@ lnet_handle_any_router_nmr_dst(struct lnet_send_data *sd)
        struct lnet_peer *gw_peer = NULL;
 
        /*
-        * Let's set if we have a preferred NI to talk to this NMR peer
+        * Let's see if we have a preferred NI to talk to this NMR peer
         */
-       sd->sd_best_ni = lnet_find_existing_preferred_best_ni(sd);
+       sd->sd_best_ni = lnet_find_existing_preferred_best_ni(sd->sd_best_lpni,
+                                                             sd->sd_cpt);
 
        /*
         * find the router and that'll find the best NI if we didn't find
@@ -2555,7 +2552,7 @@ lnet_handle_any_router_nmr_dst(struct lnet_send_data *sd)
         * set the best_ni we've chosen as the preferred one for
         * this peer
         */
-       lnet_set_non_mr_pref_nid(sd);
+       lnet_set_non_mr_pref_nid(sd->sd_best_lpni, sd->sd_best_ni, sd->sd_msg);
 
        /* we'll be sending to the gw */
        sd->sd_best_lpni = gw_lpni;
@@ -2662,21 +2659,22 @@ again:
        }
 
        /*
-        * Cache the original src_nid. If we need to resend the message
-        * then we'll need to know whether the src_nid was originally
+        * Cache the original src_nid and rtr_nid. If we need to resend the
+        * message then we'll need to know whether the src_nid was originally
         * specified for this message. If it was originally specified,
         * then we need to keep using the same src_nid since it's
-        * continuing the same sequence of messages.
+        * continuing the same sequence of messages. Similarly, rtr_nid will
+        * affect our choice of next hop.
         */
        msg->msg_src_nid_param = src_nid;
+       msg->msg_rtr_nid_param = rtr_nid;
 
        /*
-        * Now that we have a peer_ni, check if we want to discover
-        * the peer. Traffic to the LNET_RESERVED_PORTAL should not
-        * trigger discovery.
+        * If necessary, perform discovery on the peer that owns this peer_ni.
+        * Note, this can result in the ownership of this peer_ni changing
+        * to another peer object.
         */
-       peer = lpni->lpni_peer_net->lpn_peer;
-       rc = lnet_initiate_peer_discovery(lpni, msg, rtr_nid, cpt);
+       rc = lnet_initiate_peer_discovery(lpni, msg, cpt);
        if (rc) {
                lnet_peer_ni_decref_locked(lpni);
                lnet_net_unlock(cpt);
@@ -2684,6 +2682,8 @@ again:
        }
        lnet_peer_ni_decref_locked(lpni);
 
+       peer = lpni->lpni_peer_net->lpn_peer;
+
        /*
         * Identify the different send cases
         */
@@ -2707,8 +2707,7 @@ again:
        else
                send_case |= MR_DST;
 
-       if (msg->msg_type == LNET_MSG_REPLY ||
-           msg->msg_type == LNET_MSG_ACK)
+       if (lnet_msg_is_response(msg))
                send_case |= SND_RESP;
 
        /* assign parameters to the send_data */
@@ -2852,7 +2851,6 @@ static void
 lnet_finalize_expired_responses(void)
 {
        struct lnet_libmd *md;
-       struct list_head local_queue;
        struct lnet_rsp_tracker *rspt, *tmp;
        ktime_t now;
        int i;
@@ -2861,7 +2859,7 @@ lnet_finalize_expired_responses(void)
                return;
 
        cfs_cpt_for_each(i, lnet_cpt_table()) {
-               INIT_LIST_HEAD(&local_queue);
+               LIST_HEAD(local_queue);
 
                lnet_net_lock(i);
                if (!the_lnet.ln_mt_rstq[i]) {
@@ -3089,8 +3087,8 @@ static void
 lnet_recover_local_nis(void)
 {
        struct lnet_mt_event_info *ev_info;
-       struct list_head processed_list;
-       struct list_head local_queue;
+       LIST_HEAD(processed_list);
+       LIST_HEAD(local_queue);
        struct lnet_handle_md mdh;
        struct lnet_ni *tmp;
        struct lnet_ni *ni;
@@ -3098,9 +3096,6 @@ lnet_recover_local_nis(void)
        int healthv;
        int rc;
 
-       INIT_LIST_HEAD(&local_queue);
-       INIT_LIST_HEAD(&processed_list);
-
        /*
         * splice the recovery queue on a local queue. We will iterate
         * through the local queue and update it as needed. Once we're
@@ -3331,11 +3326,9 @@ static void
 lnet_clean_resendqs(void)
 {
        struct lnet_msg *msg, *tmp;
-       struct list_head msgs;
+       LIST_HEAD(msgs);
        int i;
 
-       INIT_LIST_HEAD(&msgs);
-
        cfs_cpt_for_each(i, lnet_cpt_table()) {
                lnet_net_lock(i);
                list_splice_init(the_lnet.ln_mt_resendqs[i], &msgs);
@@ -3354,8 +3347,8 @@ static void
 lnet_recover_peer_nis(void)
 {
        struct lnet_mt_event_info *ev_info;
-       struct list_head processed_list;
-       struct list_head local_queue;
+       LIST_HEAD(processed_list);
+       LIST_HEAD(local_queue);
        struct lnet_handle_md mdh;
        struct lnet_peer_ni *lpni;
        struct lnet_peer_ni *tmp;
@@ -3363,9 +3356,6 @@ lnet_recover_peer_nis(void)
        int healthv;
        int rc;
 
-       INIT_LIST_HEAD(&local_queue);
-       INIT_LIST_HEAD(&processed_list);
-
        /*
         * Always use cpt 0 for locking across all interactions with
         * ln_mt_peerNIRecovq
@@ -3824,8 +3814,6 @@ void lnet_monitor_thr_stop(void)
        lnet_clean_local_ni_recoveryq();
        lnet_clean_peer_ni_recoveryq();
        lnet_clean_resendqs();
-
-       return;
 }
 
 void
@@ -3996,8 +3984,8 @@ lnet_parse_reply(struct lnet_ni *ni, struct lnet_msg *msg)
        struct lnet_hdr *hdr = &msg->msg_hdr;
        struct lnet_process_id src = {0};
        struct lnet_libmd *md;
-       int rlength;
-       int mlength;
+       unsigned int rlength;
+       unsigned int mlength;
        int cpt;
 
        cpt = lnet_cpt_of_cookie(hdr->msg.reply.dst_wmd.wh_object_cookie);
@@ -4026,7 +4014,7 @@ lnet_parse_reply(struct lnet_ni *ni, struct lnet_msg *msg)
        LASSERT(md->md_offset == 0);
 
        rlength = hdr->payload_length;
-       mlength = MIN(rlength, (int)md->md_length);
+       mlength = min(rlength, md->md_length);
 
        if (mlength < rlength &&
            (md->md_options & LNET_MD_TRUNCATE) == 0) {
@@ -4386,8 +4374,8 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
 
        if (!list_empty(&the_lnet.ln_drop_rules) &&
            lnet_drop_rule_match(hdr, ni->ni_nid, NULL)) {
-               CDEBUG(D_NET, "%s, src %s, dst %s: Dropping %s to simulate"
-                             "silent message loss\n",
+               CDEBUG(D_NET,
+                      "%s, src %s, dst %s: Dropping %s to simulate silent message loss\n",
                       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
                       libcfs_nid2str(dest_nid), lnet_msgtyp2str(type));
                goto drop;
@@ -4636,7 +4624,6 @@ lnet_attach_rsp_tracker(struct lnet_rsp_tracker *rspt, int cpt,
                        struct lnet_libmd *md, struct lnet_handle_md mdh)
 {
        s64 timeout_ns;
-       bool new_entry = true;
        struct lnet_rsp_tracker *local_rspt;
 
        /*
@@ -4655,8 +4642,7 @@ lnet_attach_rsp_tracker(struct lnet_rsp_tracker *rspt, int cpt,
                 * we already have an rspt attached to the md, so we'll
                 * update the deadline on that one.
                 */
-               LIBCFS_FREE(rspt, sizeof(*rspt));
-               new_entry = false;
+               lnet_rspt_free(rspt, cpt);
        } else {
                /* new md */
                rspt->rspt_mdh = mdh;
@@ -4672,9 +4658,7 @@ lnet_attach_rsp_tracker(struct lnet_rsp_tracker *rspt, int cpt,
         * list in order to expire all the older entries first.
         */
        lnet_net_lock(cpt);
-       if (!new_entry && !list_empty(&local_rspt->rspt_on_list))
-               list_del_init(&local_rspt->rspt_on_list);
-       list_add_tail(&local_rspt->rspt_on_list, the_lnet.ln_mt_rstq[cpt]);
+       list_move_tail(&local_rspt->rspt_on_list, the_lnet.ln_mt_rstq[cpt]);
        lnet_net_unlock(cpt);
        lnet_res_unlock(cpt);
 }
@@ -4776,7 +4760,7 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
                               md->md_me->me_portal);
                lnet_res_unlock(cpt);
 
-               LIBCFS_FREE(rspt, sizeof(*rspt));
+               lnet_rspt_free(rspt, cpt);
                lnet_msg_free(msg);
                return -ENOENT;
        }
@@ -5003,7 +4987,7 @@ LNetGet(lnet_nid_t self, struct lnet_handle_md mdh,
                lnet_res_unlock(cpt);
 
                lnet_msg_free(msg);
-               LIBCFS_FREE(rspt, sizeof(*rspt));
+               lnet_rspt_free(rspt, cpt);
                return -ENOENT;
        }
 
@@ -5098,9 +5082,9 @@ LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
                         * current net namespace.
                         * If not, assign order above 0xffff0000,
                         * to make this ni not a priority. */
-                       if (!net_eq(ni->ni_net_ns, current->nsproxy->net_ns))
-                               order += 0xffff0000;
-
+                       if (current->nsproxy &&
+                           !net_eq(ni->ni_net_ns, current->nsproxy->net_ns))
+                                       order += 0xffff0000;
                        if (srcnidp != NULL)
                                *srcnidp = ni->ni_nid;
                        if (orderp != NULL)