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LU-13569 lnet: Recover local NI w/exponential backoff interval
[fs/lustre-release.git] / lnet / lnet / lib-move.c
index e9daed8..c9b14f5 100644 (file)
@@ -27,7 +27,6 @@
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * lnet/lnet/lib-move.c
  *
@@ -63,6 +62,36 @@ 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 bool
+lnet_response_tracking_enabled(__u32 msg_type, unsigned int md_options)
+{
+       if (md_options & LNET_MD_NO_TRACK_RESPONSE)
+               /* Explicitly disabled in MD options */
+               return false;
+
+       if (md_options & LNET_MD_TRACK_RESPONSE)
+               /* Explicity enabled in MD options */
+               return true;
+
+       if (lnet_response_tracking == 3)
+               /* Enabled for all message types */
+               return true;
+
+       if (msg_type == LNET_MSG_PUT)
+               return lnet_response_tracking == 2;
+
+       if (msg_type == LNET_MSG_GET)
+               return lnet_response_tracking == 1;
+
+       return false;
+}
+
 static inline struct lnet_comm_count *
 get_stats_counts(struct lnet_element_stats *stats,
                 enum lnet_stats_type stats_type)
@@ -165,7 +194,7 @@ 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) {
@@ -183,9 +212,6 @@ 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) {
@@ -215,10 +241,8 @@ 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);
@@ -284,7 +308,7 @@ 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;
@@ -310,9 +334,9 @@ 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);
@@ -337,70 +361,24 @@ lnet_copy_iov2iov(unsigned int ndiov, struct kvec *diov, unsigned int doffset,
 }
 EXPORT_SYMBOL(lnet_copy_iov2iov);
 
-int
-lnet_extract_iov(int dst_niov, struct kvec *dst,
-                int src_niov, struct kvec *src,
-                unsigned int offset, unsigned int len)
-{
-       /* Initialise 'dst' to the subset of 'src' starting at 'offset',
-        * for exactly 'len' bytes, and return the number of entries.
-        * NB not destructive to 'src' */
-       unsigned int    frag_len;
-       unsigned int    niov;
-
-       if (len == 0)                           /* no data => */
-               return (0);                     /* no frags */
-
-       LASSERT(src_niov > 0);
-       while (offset >= src->iov_len) {      /* skip initial frags */
-               offset -= src->iov_len;
-               src_niov--;
-               src++;
-               LASSERT(src_niov > 0);
-       }
-
-       niov = 1;
-       for (;;) {
-               LASSERT(src_niov > 0);
-               LASSERT((int)niov <= dst_niov);
-
-               frag_len = src->iov_len - offset;
-               dst->iov_base = ((char *)src->iov_base) + offset;
-
-               if (len <= frag_len) {
-                       dst->iov_len = len;
-                       return (niov);
-               }
-
-               dst->iov_len = frag_len;
-
-               len -= frag_len;
-               dst++;
-               src++;
-               niov++;
-               src_niov--;
-               offset = 0;
-       }
-}
-EXPORT_SYMBOL(lnet_extract_iov);
-
-
 unsigned int
-lnet_kiov_nob(unsigned int niov, lnet_kiov_t *kiov)
+lnet_kiov_nob(unsigned int niov, struct bio_vec *kiov)
 {
        unsigned int  nob = 0;
 
        LASSERT(niov == 0 || kiov != NULL);
        while (niov-- > 0)
-               nob += (kiov++)->kiov_len;
+               nob += (kiov++)->bv_len;
 
        return (nob);
 }
 EXPORT_SYMBOL(lnet_kiov_nob);
 
 void
-lnet_copy_kiov2kiov(unsigned int ndiov, lnet_kiov_t *diov, unsigned int doffset,
-                   unsigned int nsiov, lnet_kiov_t *siov, unsigned int soffset,
+lnet_copy_kiov2kiov(unsigned int ndiov, struct bio_vec *diov,
+                   unsigned int doffset,
+                   unsigned int nsiov, struct bio_vec *siov,
+                   unsigned int soffset,
                    unsigned int nob)
 {
        /* NB diov, siov are READ-ONLY */
@@ -414,16 +392,16 @@ lnet_copy_kiov2kiov(unsigned int ndiov, lnet_kiov_t *diov, unsigned int doffset,
        LASSERT (!in_interrupt ());
 
        LASSERT (ndiov > 0);
-       while (doffset >= diov->kiov_len) {
-               doffset -= diov->kiov_len;
+       while (doffset >= diov->bv_len) {
+               doffset -= diov->bv_len;
                diov++;
                ndiov--;
                LASSERT(ndiov > 0);
        }
 
        LASSERT(nsiov > 0);
-       while (soffset >= siov->kiov_len) {
-               soffset -= siov->kiov_len;
+       while (soffset >= siov->bv_len) {
+               soffset -= siov->bv_len;
                siov++;
                nsiov--;
                LASSERT(nsiov > 0);
@@ -432,16 +410,16 @@ 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->bv_len - doffset,
+                               siov->bv_len - soffset,
+                               nob);
 
                if (daddr == NULL)
-                       daddr = ((char *)kmap(diov->kiov_page)) +
-                               diov->kiov_offset + doffset;
+                       daddr = ((char *)kmap(diov->bv_page)) +
+                               diov->bv_offset + doffset;
                if (saddr == NULL)
-                       saddr = ((char *)kmap(siov->kiov_page)) +
-                               siov->kiov_offset + soffset;
+                       saddr = ((char *)kmap(siov->bv_page)) +
+                               siov->bv_offset + soffset;
 
                /* Vanishing risk of kmap deadlock when mapping 2 pages.
                 * However in practice at least one of the kiovs will be mapped
@@ -450,22 +428,22 @@ lnet_copy_kiov2kiov(unsigned int ndiov, lnet_kiov_t *diov, unsigned int doffset,
                memcpy (daddr, saddr, this_nob);
                nob -= this_nob;
 
-               if (diov->kiov_len > doffset + this_nob) {
+               if (diov->bv_len > doffset + this_nob) {
                        daddr += this_nob;
                        doffset += this_nob;
                } else {
-                       kunmap(diov->kiov_page);
+                       kunmap(diov->bv_page);
                        daddr = NULL;
                        diov++;
                        ndiov--;
                        doffset = 0;
                }
 
-               if (siov->kiov_len > soffset + this_nob) {
+               if (siov->bv_len > soffset + this_nob) {
                        saddr += this_nob;
                        soffset += this_nob;
                } else {
-                       kunmap(siov->kiov_page);
+                       kunmap(siov->bv_page);
                        saddr = NULL;
                        siov++;
                        nsiov--;
@@ -474,15 +452,16 @@ lnet_copy_kiov2kiov(unsigned int ndiov, lnet_kiov_t *diov, unsigned int doffset,
        } while (nob > 0);
 
        if (daddr != NULL)
-               kunmap(diov->kiov_page);
+               kunmap(diov->bv_page);
        if (saddr != NULL)
-               kunmap(siov->kiov_page);
+               kunmap(siov->bv_page);
 }
 EXPORT_SYMBOL(lnet_copy_kiov2kiov);
 
 void
 lnet_copy_kiov2iov (unsigned int niov, struct kvec *iov, unsigned int iovoffset,
-                   unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffset,
+                   unsigned int nkiov, struct bio_vec *kiov,
+                   unsigned int kiovoffset,
                    unsigned int nob)
 {
        /* NB iov, kiov are READ-ONLY */
@@ -503,8 +482,8 @@ lnet_copy_kiov2iov (unsigned int niov, struct kvec *iov, unsigned int iovoffset,
        }
 
        LASSERT(nkiov > 0);
-       while (kiovoffset >= kiov->kiov_len) {
-               kiovoffset -= kiov->kiov_len;
+       while (kiovoffset >= kiov->bv_len) {
+               kiovoffset -= kiov->bv_len;
                kiov++;
                nkiov--;
                LASSERT(nkiov > 0);
@@ -513,13 +492,13 @@ 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->bv_len - kiovoffset,
+                               nob);
 
                if (addr == NULL)
-                       addr = ((char *)kmap(kiov->kiov_page)) +
-                               kiov->kiov_offset + kiovoffset;
+                       addr = ((char *)kmap(kiov->bv_page)) +
+                               kiov->bv_offset + kiovoffset;
 
                memcpy((char *)iov->iov_base + iovoffset, addr, this_nob);
                nob -= this_nob;
@@ -532,11 +511,11 @@ lnet_copy_kiov2iov (unsigned int niov, struct kvec *iov, unsigned int iovoffset,
                        iovoffset = 0;
                }
 
-               if (kiov->kiov_len > kiovoffset + this_nob) {
+               if (kiov->bv_len > kiovoffset + this_nob) {
                        addr += this_nob;
                        kiovoffset += this_nob;
                } else {
-                       kunmap(kiov->kiov_page);
+                       kunmap(kiov->bv_page);
                        addr = NULL;
                        kiov++;
                        nkiov--;
@@ -546,12 +525,13 @@ lnet_copy_kiov2iov (unsigned int niov, struct kvec *iov, unsigned int iovoffset,
        } while (nob > 0);
 
        if (addr != NULL)
-               kunmap(kiov->kiov_page);
+               kunmap(kiov->bv_page);
 }
 EXPORT_SYMBOL(lnet_copy_kiov2iov);
 
 void
-lnet_copy_iov2kiov(unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffset,
+lnet_copy_iov2kiov(unsigned int nkiov, struct bio_vec *kiov,
+                  unsigned int kiovoffset,
                   unsigned int niov, struct kvec *iov, unsigned int iovoffset,
                   unsigned int nob)
 {
@@ -565,8 +545,8 @@ lnet_copy_iov2kiov(unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffse
        LASSERT (!in_interrupt ());
 
        LASSERT (nkiov > 0);
-       while (kiovoffset >= kiov->kiov_len) {
-               kiovoffset -= kiov->kiov_len;
+       while (kiovoffset >= kiov->bv_len) {
+               kiovoffset -= kiov->bv_len;
                kiov++;
                nkiov--;
                LASSERT(nkiov > 0);
@@ -583,22 +563,22 @@ 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->bv_len - kiovoffset,
+                               (unsigned int)iov->iov_len - iovoffset,
+                               nob);
 
                if (addr == NULL)
-                       addr = ((char *)kmap(kiov->kiov_page)) +
-                               kiov->kiov_offset + kiovoffset;
+                       addr = ((char *)kmap(kiov->bv_page)) +
+                               kiov->bv_offset + kiovoffset;
 
                memcpy (addr, (char *)iov->iov_base + iovoffset, this_nob);
                nob -= this_nob;
 
-               if (kiov->kiov_len > kiovoffset + this_nob) {
+               if (kiov->bv_len > kiovoffset + this_nob) {
                        addr += this_nob;
                        kiovoffset += this_nob;
                } else {
-                       kunmap(kiov->kiov_page);
+                       kunmap(kiov->bv_page);
                        addr = NULL;
                        kiov++;
                        nkiov--;
@@ -615,13 +595,13 @@ lnet_copy_iov2kiov(unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffse
        } while (nob > 0);
 
        if (addr != NULL)
-               kunmap(kiov->kiov_page);
+               kunmap(kiov->bv_page);
 }
 EXPORT_SYMBOL(lnet_copy_iov2kiov);
 
 int
-lnet_extract_kiov(int dst_niov, lnet_kiov_t *dst,
-                 int src_niov, lnet_kiov_t *src,
+lnet_extract_kiov(int dst_niov, struct bio_vec *dst,
+                 int src_niov, struct bio_vec *src,
                  unsigned int offset, unsigned int len)
 {
        /* Initialise 'dst' to the subset of 'src' starting at 'offset',
@@ -634,8 +614,8 @@ lnet_extract_kiov(int dst_niov, lnet_kiov_t *dst,
                return (0);                     /* no frags */
 
        LASSERT(src_niov > 0);
-       while (offset >= src->kiov_len) {      /* skip initial frags */
-               offset -= src->kiov_len;
+       while (offset >= src->bv_len) {      /* skip initial frags */
+               offset -= src->bv_len;
                src_niov--;
                src++;
                LASSERT(src_niov > 0);
@@ -646,18 +626,18 @@ lnet_extract_kiov(int dst_niov, lnet_kiov_t *dst,
                LASSERT(src_niov > 0);
                LASSERT((int)niov <= dst_niov);
 
-               frag_len = src->kiov_len - offset;
-               dst->kiov_page = src->kiov_page;
-               dst->kiov_offset = src->kiov_offset + offset;
+               frag_len = src->bv_len - offset;
+               dst->bv_page = src->bv_page;
+               dst->bv_offset = src->bv_offset + offset;
 
                if (len <= frag_len) {
-                       dst->kiov_len = len;
-                       LASSERT(dst->kiov_offset + dst->kiov_len <= PAGE_SIZE);
+                       dst->bv_len = len;
+                       LASSERT(dst->bv_offset + dst->bv_len <= PAGE_SIZE);
                        return niov;
                }
 
-               dst->kiov_len = frag_len;
-               LASSERT(dst->kiov_offset + dst->kiov_len <= PAGE_SIZE);
+               dst->bv_len = frag_len;
+               LASSERT(dst->bv_offset + dst->bv_len <= PAGE_SIZE);
 
                len -= frag_len;
                dst++;
@@ -674,10 +654,10 @@ lnet_ni_recv(struct lnet_ni *ni, void *private, struct lnet_msg *msg,
             int delayed, unsigned int offset, unsigned int mlen,
             unsigned int rlen)
 {
-       unsigned int  niov = 0;
+       unsigned int niov = 0;
        struct kvec *iov = NULL;
-       lnet_kiov_t  *kiov = NULL;
-       int           rc;
+       struct bio_vec  *kiov = NULL;
+       int rc;
 
        LASSERT (!in_interrupt ());
        LASSERT (mlen == 0 || msg != NULL);
@@ -694,7 +674,6 @@ lnet_ni_recv(struct lnet_ni *ni, void *private, struct lnet_msg *msg,
 
                if (mlen != 0) {
                        niov = msg->msg_niov;
-                       iov  = msg->msg_iov;
                        kiov = msg->msg_kiov;
 
                        LASSERT (niov > 0);
@@ -703,7 +682,7 @@ lnet_ni_recv(struct lnet_ni *ni, void *private, struct lnet_msg *msg,
        }
 
        rc = (ni->ni_net->net_lnd->lnd_recv)(ni, private, msg, delayed,
-                                            niov, iov, kiov, offset, mlen,
+                                            niov, kiov, offset, mlen,
                                             rlen);
        if (rc < 0)
                lnet_finalize(msg, rc);
@@ -718,14 +697,10 @@ lnet_setpayloadbuffer(struct lnet_msg *msg)
        LASSERT(!msg->msg_routing);
        LASSERT(md != NULL);
        LASSERT(msg->msg_niov == 0);
-       LASSERT(msg->msg_iov == NULL);
        LASSERT(msg->msg_kiov == NULL);
 
        msg->msg_niov = md->md_niov;
-       if ((md->md_options & LNET_MD_KIOV) != 0)
-               msg->msg_kiov = md->md_iov.kiov;
-       else
-               msg->msg_iov = md->md_iov.iov;
+       msg->msg_kiov = md->md_kiov;
 }
 
 void
@@ -753,12 +728,12 @@ lnet_prep_send(struct lnet_msg *msg, int type, struct lnet_process_id target,
 static void
 lnet_ni_send(struct lnet_ni *ni, struct lnet_msg *msg)
 {
-       void   *priv = msg->msg_private;
+       void *priv = msg->msg_private;
        int rc;
 
-       LASSERT (!in_interrupt ());
-       LASSERT (LNET_NETTYP(LNET_NIDNET(ni->ni_nid)) == LOLND ||
-                (msg->msg_txcredit && msg->msg_peertxcredit));
+       LASSERT(!in_interrupt());
+       LASSERT(ni->ni_nid == LNET_NID_LO_0 ||
+               (msg->msg_txcredit && msg->msg_peertxcredit));
 
        rc = (ni->ni_net->net_lnd->lnd_send)(ni, priv, msg);
        if (rc < 0) {
@@ -832,8 +807,7 @@ 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))
@@ -865,8 +839,10 @@ lnet_post_send_locked(struct lnet_msg *msg, int do_send)
        LASSERT(!do_send || msg->msg_tx_delayed);
        LASSERT(!msg->msg_receiving);
        LASSERT(msg->msg_tx_committed);
+
        /* can't get here if we're sending to the loopback interface */
-       LASSERT(lp->lpni_nid != the_lnet.ln_loni->ni_nid);
+       if (the_lnet.ln_loni)
+               LASSERT(lp->lpni_nid != the_lnet.ln_loni->ni_nid);
 
        /* NB 'lp' is always the next hop */
        if ((msg->msg_target.pid & LNET_PID_USERFLAG) == 0 &&
@@ -995,7 +971,6 @@ lnet_post_routed_recv_locked(struct lnet_msg *msg, int do_recv)
        struct lnet_rtrbufpool *rbp;
        struct lnet_rtrbuf *rb;
 
-       LASSERT(msg->msg_iov == NULL);
        LASSERT(msg->msg_kiov == NULL);
        LASSERT(msg->msg_niov == 0);
        LASSERT(msg->msg_routing);
@@ -1012,8 +987,6 @@ lnet_post_routed_recv_locked(struct lnet_msg *msg, int do_recv)
        if (!msg->msg_peerrtrcredit) {
                /* lpni_lock protects the credit manipulation */
                spin_lock(&lpni->lpni_lock);
-               /* lp_lock protects the lp_rtrq */
-               spin_lock(&lp->lp_lock);
 
                msg->msg_peerrtrcredit = 1;
                lpni->lpni_rtrcredits--;
@@ -1021,15 +994,16 @@ lnet_post_routed_recv_locked(struct lnet_msg *msg, int do_recv)
                        lpni->lpni_minrtrcredits = lpni->lpni_rtrcredits;
 
                if (lpni->lpni_rtrcredits < 0) {
+                       spin_unlock(&lpni->lpni_lock);
                        /* must have checked eager_recv before here */
                        LASSERT(msg->msg_rx_ready_delay);
                        msg->msg_rx_delayed = 1;
+                       /* lp_lock protects the lp_rtrq */
+                       spin_lock(&lp->lp_lock);
                        list_add_tail(&msg->msg_list, &lp->lp_rtrq);
                        spin_unlock(&lp->lp_lock);
-                       spin_unlock(&lpni->lpni_lock);
                        return LNET_CREDIT_WAIT;
                }
-               spin_unlock(&lp->lp_lock);
                spin_unlock(&lpni->lpni_lock);
        }
 
@@ -1256,24 +1230,22 @@ routing_off:
                LASSERT(rxpeerni->lpni_peer_net);
                LASSERT(rxpeerni->lpni_peer_net->lpn_peer);
 
-               lp = rxpeerni->lpni_peer_net->lpn_peer;
-
                /* give back peer router credits */
                msg->msg_peerrtrcredit = 0;
 
                spin_lock(&rxpeerni->lpni_lock);
-               spin_lock(&lp->lp_lock);
-
                rxpeerni->lpni_rtrcredits++;
+               spin_unlock(&rxpeerni->lpni_lock);
+
+               lp = rxpeerni->lpni_peer_net->lpn_peer;
+               spin_lock(&lp->lp_lock);
 
                /* 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);
                        lnet_drop_routed_msgs_locked(&drop, msg->msg_rx_cpt);
                } else if (!list_empty(&lp->lp_rtrq)) {
                        int msg2_cpt;
@@ -1283,7 +1255,6 @@ routing_off:
                        list_del(&msg2->msg_list);
                        msg2_cpt = msg2->msg_rx_cpt;
                        spin_unlock(&lp->lp_lock);
-                       spin_unlock(&rxpeerni->lpni_lock);
                        /*
                         * messages on the lp_rtrq can be from any NID in
                         * the peer, which means they might have different
@@ -1301,7 +1272,6 @@ routing_off:
                        }
                } else {
                        spin_unlock(&lp->lp_lock);
-                       spin_unlock(&rxpeerni->lpni_lock);
                }
        }
        if (rxni != NULL) {
@@ -1314,27 +1284,10 @@ routing_off:
        }
 }
 
-static int
-lnet_compare_peers(struct lnet_peer_ni *p1, struct lnet_peer_ni *p2)
-{
-       if (p1->lpni_txqnob < p2->lpni_txqnob)
-               return 1;
-
-       if (p1->lpni_txqnob > p2->lpni_txqnob)
-               return -1;
-
-       if (p1->lpni_txcredits > p2->lpni_txcredits)
-               return 1;
-
-       if (p1->lpni_txcredits < p2->lpni_txcredits)
-               return -1;
-
-       return 0;
-}
-
 static struct lnet_peer_ni *
 lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
                    struct lnet_peer *peer,
+                   struct lnet_peer_ni *best_lpni,
                    struct lnet_peer_net *peer_net)
 {
        /*
@@ -1346,12 +1299,15 @@ lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
         * credits are equal, we round-robin over the peer_ni.
         */
        struct lnet_peer_ni *lpni = NULL;
-       struct lnet_peer_ni *best_lpni = NULL;
-       int best_lpni_credits = INT_MIN;
-       bool preferred = false;
-       bool ni_is_pref;
-       int best_lpni_healthv = 0;
+       int best_lpni_credits = (best_lpni) ? best_lpni->lpni_txcredits :
+               INT_MIN;
+       int best_lpni_healthv = (best_lpni) ?
+               atomic_read(&best_lpni->lpni_healthv) : 0;
+       bool best_lpni_is_preferred = false;
+       bool lpni_is_preferred;
        int lpni_healthv;
+       __u32 lpni_sel_prio;
+       __u32 best_sel_prio = LNET_MAX_SELECTION_PRIORITY;
 
        while ((lpni = lnet_get_next_peer_ni_locked(peer, peer_net, lpni))) {
                /*
@@ -1359,56 +1315,76 @@ lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
                 * preferred, then let's use it
                 */
                if (best_ni) {
-                       ni_is_pref = lnet_peer_is_pref_nid_locked(lpni,
+                       lpni_is_preferred = lnet_peer_is_pref_nid_locked(lpni,
                                                                best_ni->ni_nid);
-                       CDEBUG(D_NET, "%s ni_is_pref = %d\n",
-                              libcfs_nid2str(best_ni->ni_nid), ni_is_pref);
+                       CDEBUG(D_NET, "%s lpni_is_preferred = %d\n",
+                              libcfs_nid2str(best_ni->ni_nid),
+                              lpni_is_preferred);
                } else {
-                       ni_is_pref = false;
+                       lpni_is_preferred = false;
                }
 
                lpni_healthv = atomic_read(&lpni->lpni_healthv);
+               lpni_sel_prio = lpni->lpni_sel_priority;
 
                if (best_lpni)
-                       CDEBUG(D_NET, "%s c:[%d, %d], s:[%d, %d]\n",
+                       CDEBUG(D_NET, "n:[%s, %s] h:[%d, %d] p:[%d, %d] c:[%d, %d] s:[%d, %d]\n",
                                libcfs_nid2str(lpni->lpni_nid),
+                               libcfs_nid2str(best_lpni->lpni_nid),
+                               lpni_healthv, best_lpni_healthv,
+                               lpni_sel_prio, best_sel_prio,
                                lpni->lpni_txcredits, best_lpni_credits,
                                lpni->lpni_seq, best_lpni->lpni_seq);
+               else
+                       goto select_lpni;
 
                /* pick the healthiest peer ni */
-               if (lpni_healthv < best_lpni_healthv) {
+               if (lpni_healthv < best_lpni_healthv)
                        continue;
-               } else if (lpni_healthv > best_lpni_healthv) {
-                       best_lpni_healthv = lpni_healthv;
+               else if (lpni_healthv > best_lpni_healthv) {
+                       if (best_lpni_is_preferred)
+                               best_lpni_is_preferred = false;
+                       goto select_lpni;
+               }
+
+               if (lpni_sel_prio > best_sel_prio)
+                       continue;
+               else if (lpni_sel_prio < best_sel_prio) {
+                       if (best_lpni_is_preferred)
+                               best_lpni_is_preferred = false;
+                       goto select_lpni;
+               }
+
                /* if this is a preferred peer use it */
-               } else if (!preferred && ni_is_pref) {
-                       preferred = true;
-               } else if (preferred && !ni_is_pref) {
-                       /*
-                        * this is not the preferred peer so let's ignore
+               if (!best_lpni_is_preferred && lpni_is_preferred) {
+                       best_lpni_is_preferred = true;
+                       goto select_lpni;
+               } else if (best_lpni_is_preferred && !lpni_is_preferred) {
+                       /* this is not the preferred peer so let's ignore
                         * it.
                         */
                        continue;
-               } else if (lpni->lpni_txcredits < best_lpni_credits) {
-                       /*
-                        * We already have a peer that has more credits
+               }
+
+               if (lpni->lpni_txcredits < best_lpni_credits)
+                       /* We already have a peer that has more credits
                         * available than this one. No need to consider
                         * this peer further.
                         */
                        continue;
-               } else if (lpni->lpni_txcredits == best_lpni_credits) {
-                       /*
-                        * The best peer found so far and the current peer
-                        * have the same number of available credits let's
-                        * make sure to select between them using Round
-                        * Robin
-                        */
-                       if (best_lpni) {
-                               if (best_lpni->lpni_seq <= lpni->lpni_seq)
-                                       continue;
-                       }
-               }
+               else if (lpni->lpni_txcredits > best_lpni_credits)
+                       goto select_lpni;
 
+               /* The best peer found so far and the current peer
+                * have the same number of available credits let's
+                * make sure to select between them using Round Robin
+                */
+               if (best_lpni && (best_lpni->lpni_seq <= lpni->lpni_seq))
+                       continue;
+select_lpni:
+               best_lpni_is_preferred = lpni_is_preferred;
+               best_lpni_healthv = lpni_healthv;
+               best_sel_prio = lpni_sel_prio;
                best_lpni = lpni;
                best_lpni_credits = lpni->lpni_txcredits;
        }
@@ -1430,127 +1406,191 @@ 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
+ * Find the best lpni.
+ * If the net id is provided then restrict lpni selection on
+ * that particular net.
+ * Otherwise find any reachable lpni. When dealing with an MR
+ * gateway and it has multiple lpnis which we can use
+ * we want to select the best one from the list of reachable
+ * ones.
  */
 static inline struct lnet_peer_ni *
-lnet_find_best_lpni_on_net(struct lnet_ni *lni, lnet_nid_t dst_nid,
-                          struct lnet_peer *peer, __u32 net_id)
+lnet_find_best_lpni(struct lnet_ni *lni, lnet_nid_t dst_nid,
+                   struct lnet_peer *peer, __u32 net_id)
 {
        struct lnet_peer_net *peer_net;
 
-       /*
-        * The gateway is Multi-Rail capable so now we must select the
-        * proper peer_ni
-        */
-       peer_net = lnet_peer_get_net_locked(peer, net_id);
+       /* find the best_lpni on any local network */
+       if (net_id == LNET_NET_ANY) {
+               struct lnet_peer_ni *best_lpni = NULL;
+               struct lnet_peer_net *lpn;
+               list_for_each_entry(lpn, &peer->lp_peer_nets, lpn_peer_nets) {
+                       /* no net specified find any reachable peer ni */
+                       if (!lnet_islocalnet_locked(lpn->lpn_net_id))
+                               continue;
+                       best_lpni = lnet_select_peer_ni(lni, dst_nid, peer,
+                                                       best_lpni, lpn);
+               }
 
-       if (!peer_net) {
-               CERROR("gateway peer %s has no NI on net %s\n",
-                      libcfs_nid2str(peer->lp_primary_nid),
-                      libcfs_net2str(net_id));
-               return NULL;
+               return best_lpni;
        }
+       /* restrict on the specified net */
+       peer_net = lnet_peer_get_net_locked(peer, net_id);
+       if (peer_net)
+               return lnet_select_peer_ni(lni, dst_nid, peer, NULL, peer_net);
 
-       return lnet_select_peer_ni(lni, dst_nid, peer, peer_net);
+       return NULL;
 }
 
 static int
-lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2,
-                   struct lnet_peer_ni **best_lpni)
+lnet_compare_gw_lpnis(struct lnet_peer_ni *lpni1, struct lnet_peer_ni *lpni2)
 {
-       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;
-       int rc;
+       if (lpni1->lpni_txqnob < lpni2->lpni_txqnob)
+               return 1;
 
-       lpni1 = lnet_find_best_lpni_on_net(NULL, LNET_NID_ANY, lp1,
-                                          r1->lr_lnet);
-       lpni2 = lnet_find_best_lpni_on_net(NULL, LNET_NID_ANY, lp2,
-                                          r2->lr_lnet);
-       LASSERT(lpni1 && lpni2);
+       if (lpni1->lpni_txqnob > lpni2->lpni_txqnob)
+               return -1;
 
-       if (r1->lr_priority < r2->lr_priority) {
-               *best_lpni = lpni1;
+       if (lpni1->lpni_txcredits > lpni2->lpni_txcredits)
                return 1;
-       }
 
-       if (r1->lr_priority > r2->lr_priority) {
-               *best_lpni = lpni2;
+       if (lpni1->lpni_txcredits < lpni2->lpni_txcredits)
                return -1;
-       }
 
-       if (r1_hops < r2_hops) {
-               *best_lpni = lpni1;
+       return 0;
+}
+
+/* Compare route priorities and hop counts */
+static int
+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;
+
+       if (r1->lr_priority < r2->lr_priority)
                return 1;
-       }
 
-       if (r1_hops > r2_hops) {
-               *best_lpni = lpni2;
+       if (r1->lr_priority > r2->lr_priority)
                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;
+       if (r1_hops < r2_hops)
                return 1;
-       }
 
-       *best_lpni = lpni2;
-       return -1;
+       if (r1_hops > r2_hops)
+               return -1;
+
+       return 0;
 }
 
 static struct lnet_route *
-lnet_find_route_locked(struct lnet_remotenet *rnet,
+lnet_find_route_locked(struct lnet_remotenet *rnet, __u32 src_net,
+                      struct lnet_peer_ni *remote_lpni,
                       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_peer *lp_best;
        struct lnet_route *route;
-       struct lnet_peer *lp;
        int rc;
+       bool best_rte_is_preferred = false;
+       lnet_nid_t gw_pnid;
+
+       CDEBUG(D_NET, "Looking up a route to %s, from %s\n",
+              libcfs_net2str(rnet->lrn_net), libcfs_net2str(src_net));
 
-       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;
+               gw_pnid = route->lr_gateway->lp_primary_nid;
+
+               /* no protection on below fields, but it's harmless */
+               if (last_route && (last_route->lr_seq - route->lr_seq < 0))
+                       last_route = route;
+
+               /* if the best route found is in the preferred list then
+                * tag it as preferred and use it later on. But if we
+                * didn't find any routes which are on the preferred list
+                * then just use the best route possible.
+                */
+               rc = lnet_peer_is_pref_rtr_locked(remote_lpni, gw_pnid);
+
+               if (!best_route || (rc && !best_rte_is_preferred)) {
+                       /* Restrict the selection of the router NI on the
+                        * src_net provided. If the src_net is LNET_NID_ANY,
+                        * then select the best interface available.
+                        */
+                       lpni = lnet_find_best_lpni(NULL, LNET_NID_ANY,
+                                                  route->lr_gateway,
+                                                  src_net);
+                       if (!lpni) {
+                               CDEBUG(D_NET,
+                                      "Gateway %s does not have a peer NI on net %s\n",
+                                      libcfs_nid2str(gw_pnid),
+                                      libcfs_net2str(src_net));
+                               continue;
+                       }
+               }
+
+               if (rc && !best_rte_is_preferred) {
+                       /* This is the first preferred route we found,
+                        * so it beats any route found previously
+                        */
+                       best_route = route;
+                       if (!last_route)
+                               last_route = route;
+                       best_gw_ni = lpni;
+                       best_rte_is_preferred = true;
+                       CDEBUG(D_NET, "preferred gw = %s\n",
+                              libcfs_nid2str(gw_pnid));
+                       continue;
+               } else if ((!rc) && best_rte_is_preferred)
+                       /* The best route we found so far is in the preferred
+                        * list, so it beats any non-preferred route
+                        */
+                       continue;
 
-               if (lp_best == NULL) {
+               if (!best_route) {
                        best_route = last_route = route;
-                       lp_best = lp;
-                       best_gw_ni = lnet_find_best_lpni_on_net(NULL,
-                                                               LNET_NID_ANY,
-                                                               route->lr_gateway,
-                                                               route->lr_lnet);
-                       LASSERT(best_gw_ni);
+                       best_gw_ni = lpni;
                        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);
+               if (rc == -1)
+                       continue;
 
-               rc = lnet_compare_routes(route, best_route, &best_gw_ni);
-               if (rc < 0)
+               /* Restrict the selection of the router NI on the
+                * src_net provided. If the src_net is LNET_NID_ANY,
+                * then select the best interface available.
+                */
+               lpni = lnet_find_best_lpni(NULL, LNET_NID_ANY,
+                                          route->lr_gateway,
+                                          src_net);
+               if (!lpni) {
+                       CDEBUG(D_NET,
+                              "Gateway %s does not have a peer NI on net %s\n",
+                              libcfs_nid2str(gw_pnid),
+                              libcfs_net2str(src_net));
                        continue;
+               }
+
+               if (rc == 1) {
+                       best_route = route;
+                       best_gw_ni = lpni;
+                       continue;
+               }
 
-               best_route = route;
-               lp_best = lp;
+               rc = lnet_compare_gw_lpnis(lpni, best_gw_ni);
+               if (rc == -1)
+                       continue;
+
+               if (rc == 1 || route->lr_seq <= best_route->lr_seq) {
+                       best_route = route;
+                       best_gw_ni = lpni;
+                       continue;
+               }
        }
 
        *prev_route = last_route;
@@ -1568,6 +1608,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
        unsigned int shortest_distance;
        int best_credits;
        int best_healthv;
+       __u32 best_sel_prio;
 
        /*
         * If there is no peer_ni that we can send to on this network,
@@ -1577,6 +1618,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                return best_ni;
 
        if (best_ni == NULL) {
+               best_sel_prio = LNET_MAX_SELECTION_PRIORITY;
                shortest_distance = UINT_MAX;
                best_credits = INT_MIN;
                best_healthv = 0;
@@ -1585,6 +1627,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                                                     best_ni->ni_dev_cpt);
                best_credits = atomic_read(&best_ni->ni_tx_credits);
                best_healthv = atomic_read(&best_ni->ni_healthv);
+               best_sel_prio = best_ni->ni_sel_priority;
        }
 
        while ((ni = lnet_get_next_ni_locked(local_net, ni))) {
@@ -1592,10 +1635,12 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                int ni_credits;
                int ni_healthv;
                int ni_fatal;
+               __u32 ni_sel_prio;
 
                ni_credits = atomic_read(&ni->ni_tx_credits);
                ni_healthv = atomic_read(&ni->ni_healthv);
                ni_fatal = atomic_read(&ni->ni_fatal_error_on);
+               ni_sel_prio = ni->ni_sel_priority;
 
                /*
                 * calculate the distance from the CPT on which
@@ -1606,12 +1651,6 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                                            md_cpt,
                                            ni->ni_dev_cpt);
 
-               CDEBUG(D_NET, "compare ni %s [c:%d, d:%d, s:%d] with best_ni %s [c:%d, d:%d, s:%d]\n",
-                      libcfs_nid2str(ni->ni_nid), ni_credits, distance,
-                      ni->ni_seq, (best_ni) ? libcfs_nid2str(best_ni->ni_nid)
-                       : "not seleced", best_credits, shortest_distance,
-                       (best_ni) ? best_ni->ni_seq : 0);
-
                /*
                 * All distances smaller than the NUMA range
                 * are treated equally.
@@ -1623,31 +1662,47 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                 * Select on health, shorter distance, available
                 * credits, then round-robin.
                 */
-               if (ni_fatal) {
+               if (ni_fatal)
+                       continue;
+
+               if (best_ni)
+                       CDEBUG(D_NET, "compare ni %s [c:%d, d:%d, s:%d, p:%u] with best_ni %s [c:%d, d:%d, s:%d, p:%u]\n",
+                              libcfs_nid2str(ni->ni_nid), ni_credits, distance,
+                              ni->ni_seq, ni_sel_prio,
+                              (best_ni) ? libcfs_nid2str(best_ni->ni_nid)
+                              : "not selected", best_credits, shortest_distance,
+                              (best_ni) ? best_ni->ni_seq : 0,
+                              best_sel_prio);
+               else
+                       goto select_ni;
+
+               if (ni_healthv < best_healthv)
                        continue;
-               } else if (ni_healthv < best_healthv) {
+               else if (ni_healthv > best_healthv)
+                       goto select_ni;
+
+               if (ni_sel_prio > best_sel_prio)
                        continue;
-               } else if (ni_healthv > best_healthv) {
-                       best_healthv = ni_healthv;
-                       /*
-                        * If we're going to prefer this ni because it's
-                        * the healthiest, then we should set the
-                        * shortest_distance in the algorithm in case
-                        * there are multiple NIs with the same health but
-                        * different distances.
-                        */
-                       if (distance < shortest_distance)
-                               shortest_distance = distance;
-               } else if (distance > shortest_distance) {
+               else if (ni_sel_prio < best_sel_prio)
+                       goto select_ni;
+
+               if (distance > shortest_distance)
                        continue;
-               } else if (distance < shortest_distance) {
-                       shortest_distance = distance;
-               } else if (ni_credits < best_credits) {
+               else if (distance < shortest_distance)
+                       goto select_ni;
+
+               if (ni_credits < best_credits)
                        continue;
-               } else if (ni_credits == best_credits) {
-                       if (best_ni && best_ni->ni_seq <= ni->ni_seq)
-                               continue;
-               }
+               else if (ni_credits > best_credits)
+                       goto select_ni;
+
+               if (best_ni && best_ni->ni_seq <= ni->ni_seq)
+                       continue;
+
+select_ni:
+               best_sel_prio = ni_sel_prio;
+               shortest_distance = distance;
+               best_healthv = ni_healthv;
                best_ni = ni;
                best_credits = ni_credits;
        }
@@ -1707,6 +1762,9 @@ lnet_handle_lo_send(struct lnet_send_data *sd)
        struct lnet_msg *msg = sd->sd_msg;
        int cpt = sd->sd_cpt;
 
+       if (the_lnet.ln_state != LNET_STATE_RUNNING)
+               return -ESHUTDOWN;
+
        /* No send credit hassles with LOLND */
        lnet_ni_addref_locked(the_lnet.ln_loni, cpt);
        msg->msg_hdr.dest_nid = cpu_to_le64(the_lnet.ln_loni->ni_nid);
@@ -1733,11 +1791,24 @@ lnet_handle_send(struct lnet_send_data *sd)
        __u32 routing = send_case & REMOTE_DST;
         struct lnet_rsp_tracker *rspt;
 
-       /*
-        * Increment sequence number of the selected peer so that we
-        * pick the next one in Round Robin.
+       /* Increment sequence number of the selected peer, peer net,
+        * local ni and local net so that we pick the next ones
+        * in Round Robin.
         */
        best_lpni->lpni_seq++;
+       best_lpni->lpni_peer_net->lpn_seq++;
+       best_ni->ni_seq++;
+       best_ni->ni_net->net_seq++;
+
+       CDEBUG(D_NET, "%s NI seq info: [%d:%d:%d:%u] %s LPNI seq info [%d:%d:%d:%u]\n",
+              libcfs_nid2str(best_ni->ni_nid),
+              best_ni->ni_seq, best_ni->ni_net->net_seq,
+              atomic_read(&best_ni->ni_tx_credits),
+              best_ni->ni_sel_priority,
+              libcfs_nid2str(best_lpni->lpni_nid),
+              best_lpni->lpni_seq, best_lpni->lpni_peer_net->lpn_seq,
+              best_lpni->lpni_txcredits,
+              best_lpni->lpni_sel_priority);
 
        /*
         * grab a reference on the peer_ni so it sticks around even if
@@ -1854,17 +1925,15 @@ lnet_handle_send(struct lnet_send_data *sd)
 }
 
 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_peer_is_multi_rail(lpni->lpni_peer_net->lpn_peer) &&
+           !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);
        }
 }
 
@@ -1889,10 +1958,7 @@ 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);
 }
@@ -1936,8 +2002,7 @@ struct lnet_ni *
 lnet_find_best_ni_on_spec_net(struct lnet_ni *cur_best_ni,
                              struct lnet_peer *peer,
                              struct lnet_peer_net *peer_net,
-                             int cpt,
-                             bool incr_seq)
+                             int cpt)
 {
        struct lnet_net *local_net;
        struct lnet_ni *best_ni;
@@ -1957,19 +2022,15 @@ lnet_find_best_ni_on_spec_net(struct lnet_ni *cur_best_ni,
        best_ni = lnet_get_best_ni(local_net, cur_best_ni,
                                   peer, peer_net, cpt);
 
-       if (incr_seq && best_ni)
-               best_ni->ni_seq++;
-
        return 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;
+       struct lnet_peer_ni *new_lpni;
        int rc;
 
        lnet_peer_ni_addref_locked(lpni);
@@ -1991,26 +2052,41 @@ lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni,
                lnet_peer_ni_decref_locked(lpni);
                return rc;
        }
-       /* The peer may have changed. */
-       peer = lpni->lpni_peer_net->lpn_peer;
+
+       new_lpni = lnet_find_peer_ni_locked(lpni->lpni_nid);
+       if (!new_lpni) {
+               lnet_peer_ni_decref_locked(lpni);
+               return -ENOENT;
+       }
+
+       peer = new_lpni->lpni_peer_net->lpn_peer;
        spin_lock(&peer->lp_lock);
-       if (lnet_peer_is_uptodate_locked(peer)) {
+       if (lpni == new_lpni && lnet_peer_is_uptodate_locked(peer)) {
+               /* The peer NI did not change and the peer is up to date.
+                * Nothing more to do.
+                */
                spin_unlock(&peer->lp_lock);
                lnet_peer_ni_decref_locked(lpni);
+               lnet_peer_ni_decref_locked(new_lpni);
                return 0;
        }
-       /* queue message and return */
-       msg->msg_rtr_nid_param = rtr_nid;
+       spin_unlock(&peer->lp_lock);
+
+       /* Either the peer NI changed during discovery, or the peer isn't up
+        * to date. In both cases we want to queue the message on the
+        * (possibly new) peer's pending queue and queue the peer for discovery
+        */
        msg->msg_sending = 0;
        msg->msg_txpeer = NULL;
-       list_add_tail(&msg->msg_list, &peer->lp_dc_pendq);
-       primary_nid = peer->lp_primary_nid;
-       spin_unlock(&peer->lp_lock);
+       lnet_net_unlock(cpt);
+       lnet_peer_queue_message(peer, msg);
+       lnet_net_lock(cpt);
 
        lnet_peer_ni_decref_locked(lpni);
+       lnet_peer_ni_decref_locked(new_lpni);
 
        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;
 }
@@ -2032,7 +2108,15 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
        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;
+       bool route_found = false;
+       lnet_nid_t src_nid = (sd->sd_src_nid != LNET_NID_ANY) ? sd->sd_src_nid :
+               (sd->sd_best_ni != NULL) ? sd->sd_best_ni->ni_nid :
+               LNET_NID_ANY;
+       int best_lpn_healthv = 0;
+       __u32 best_lpn_sel_prio = LNET_MAX_SELECTION_PRIORITY;
+
+       CDEBUG(D_NET, "using src nid %s for route restriction\n",
+              libcfs_nid2str(src_nid));
 
        /* 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
@@ -2040,58 +2124,112 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
         */
        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",
+               if (gwni) {
+                       gw = gwni->lpni_peer_net->lpn_peer;
+                       lnet_peer_ni_decref_locked(gwni);
+                       if (gw->lp_rtr_refcount) {
+                               local_lnet = LNET_NIDNET(sd->sd_rtr_nid);
+                               route_found = true;
+                       }
+               } else {
+                       CWARN("No peer NI for gateway %s. Attempting to find an alternative route.\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;
+       }
 
-                       if (!best_lpn) {
+       if (!route_found) {
+               if (sd->sd_msg->msg_routing) {
+                       /* If I'm routing this message then I need to find the
+                        * next hop based on the destination NID
+                        */
+                       best_rnet = lnet_find_rnet_locked(LNET_NIDNET(sd->sd_dst_nid));
+                       if (!best_rnet) {
+                               CERROR("Unable to route message to %s - Route table may be misconfigured\n",
+                                      libcfs_nid2str(sd->sd_dst_nid));
+                               return -EHOSTUNREACH;
+                       }
+               } 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;
+
+                               if (!best_lpn) {
+                                       best_lpn = lpn;
+                                       best_rnet = rnet;
+                               }
+
+                               /* select the preferred peer net */
+                               if (best_lpn_healthv > lpn->lpn_healthv)
+                                       continue;
+                               else if (best_lpn_healthv < lpn->lpn_healthv)
+                                       goto use_lpn;
+
+                               if (best_lpn_sel_prio < lpn->lpn_sel_priority)
+                                       continue;
+                               else if (best_lpn_sel_prio > lpn->lpn_sel_priority)
+                                       goto use_lpn;
+
+                               if (best_lpn->lpn_seq <= lpn->lpn_seq)
+                                       continue;
+use_lpn:
+                               best_lpn_healthv = lpn->lpn_healthv;
+                               best_lpn_sel_prio = lpn->lpn_sel_priority;
                                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;
-                       best_rnet = rnet;
-               }
+                       sd->sd_best_lpni = lnet_find_best_lpni(sd->sd_best_ni,
+                                                              sd->sd_dst_nid,
+                                                              lp,
+                                                              best_lpn->lpn_net_id);
+                       if (!sd->sd_best_lpni) {
+                               CERROR("peer %s is unreachable\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;
-               }
+                       /* We're attempting to round robin over the remote peer
+                        * NI's so update the final destination we selected
+                        */
+                       sd->sd_final_dst_lpni = sd->sd_best_lpni;
 
-               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;
+                       /* Increment the sequence number of the remote lpni so
+                        * we can round robin over the different interfaces of
+                        * the remote lpni
+                        */
+                       sd->sd_best_lpni->lpni_seq++;
                }
 
-               best_route = lnet_find_route_locked(best_rnet, &last_route,
-                                                   &gwni);
+               /*
+                * find the best route. Restrict the selection on the net of the
+                * local NI if we've already picked the local NI to send from.
+                * Otherwise, let's pick any route we can find and then find
+                * a local NI we can reach the route's gateway on. Any route we
+                * select will be reachable by virtue of the restriction we have
+                * when adding a route.
+                */
+               best_route = lnet_find_route_locked(best_rnet,
+                                                   LNET_NIDNET(src_nid),
+                                                   sd->sd_best_lpni,
+                                                   &last_route, &gwni);
+
                if (!best_route) {
                        CERROR("no route to %s from %s\n",
                               libcfs_nid2str(dst_nid),
@@ -2109,7 +2247,6 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
                gw = best_route->lr_gateway;
                LASSERT(gw == gwni->lpni_peer_net->lpn_peer);
                local_lnet = best_route->lr_lnet;
-
        }
 
        /*
@@ -2118,8 +2255,7 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
         * 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;
 
@@ -2127,8 +2263,7 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
                sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL, gw,
                                        lnet_peer_get_net_locked(gw,
                                                                 local_lnet),
-                                       sd->sd_md_cpt,
-                                       true);
+                                       sd->sd_md_cpt);
 
        if (!sd->sd_best_ni) {
                CERROR("Internal Error. Expected local ni on %s but non found :%s\n",
@@ -2147,7 +2282,8 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
        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++;
+               if (best_lpn)
+                       best_lpn->lpn_seq++;
        }
 
        return 0;
@@ -2192,10 +2328,11 @@ 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
@@ -2211,8 +2348,19 @@ struct lnet_ni *
 lnet_find_best_ni_on_local_net(struct lnet_peer *peer, int md_cpt,
                               bool discovery)
 {
-       struct lnet_peer_net *peer_net = NULL;
+       struct lnet_peer_net *lpn = NULL;
+       struct lnet_peer_net *best_lpn = NULL;
+       struct lnet_net *net = NULL;
+       struct lnet_net *best_net = NULL;
        struct lnet_ni *best_ni = NULL;
+       int best_lpn_healthv = 0;
+       int best_net_healthv = 0;
+       int net_healthv;
+       __u32 best_lpn_sel_prio = LNET_MAX_SELECTION_PRIORITY;
+       __u32 lpn_sel_prio;
+       __u32 best_net_sel_prio = LNET_MAX_SELECTION_PRIORITY;
+       __u32 net_sel_prio;
+       bool exit = false;
 
        /*
         * The peer can have multiple interfaces, some of them can be on
@@ -2222,41 +2370,92 @@ lnet_find_best_ni_on_local_net(struct lnet_peer *peer, int md_cpt,
         */
 
        /* go through all the peer nets and find the best_ni */
-       list_for_each_entry(peer_net, &peer->lp_peer_nets, lpn_peer_nets) {
+       list_for_each_entry(lpn, &peer->lp_peer_nets, lpn_peer_nets) {
                /*
                 * The peer's list of nets can contain non-local nets. We
                 * want to only examine the local ones.
                 */
-               if (!lnet_get_net_locked(peer_net->lpn_net_id))
+               net = lnet_get_net_locked(lpn->lpn_net_id);
+               if (!net)
                        continue;
-               best_ni = lnet_find_best_ni_on_spec_net(best_ni, peer,
-                                                  peer_net, md_cpt, false);
+
+               lpn_sel_prio = lpn->lpn_sel_priority;
+               net_healthv = lnet_get_net_healthv_locked(net);
+               net_sel_prio = net->net_sel_priority;
 
                /*
                 * if this is a discovery message and lp_disc_net_id is
                 * specified then use that net to send the discovery on.
                 */
-               if (peer->lp_disc_net_id == peer_net->lpn_net_id &&
-                   discovery)
+               if (peer->lp_disc_net_id == lpn->lpn_net_id &&
+                   discovery) {
+                       exit = true;
+                       goto select_lpn;
+               }
+
+               if (!best_lpn)
+                       goto select_lpn;
+
+               /* always select the lpn with the best health */
+               if (best_lpn_healthv > lpn->lpn_healthv)
+                       continue;
+               else if (best_lpn_healthv < lpn->lpn_healthv)
+                       goto select_lpn;
+
+               /* select the preferred peer and local nets */
+               if (best_lpn_sel_prio < lpn_sel_prio)
+                       continue;
+               else if (best_lpn_sel_prio > lpn_sel_prio)
+                       goto select_lpn;
+
+               if (best_net_healthv > net_healthv)
+                       continue;
+               else if (best_net_healthv < net_healthv)
+                       goto select_lpn;
+
+               if (best_net_sel_prio < net_sel_prio)
+                       continue;
+               else if (best_net_sel_prio > net_sel_prio)
+                       goto select_lpn;
+
+               if (best_lpn->lpn_seq < lpn->lpn_seq)
+                       continue;
+               else if (best_lpn->lpn_seq > lpn->lpn_seq)
+                       goto select_lpn;
+
+               /* round robin over the local networks */
+               if (best_net->net_seq <= net->net_seq)
+                       continue;
+
+select_lpn:
+               best_net_healthv = net_healthv;
+               best_net_sel_prio = net_sel_prio;
+               best_lpn_healthv = lpn->lpn_healthv;
+               best_lpn_sel_prio = lpn_sel_prio;
+               best_lpn = lpn;
+               best_net = net;
+
+               if (exit)
                        break;
        }
 
-       if (best_ni)
-               /* increment sequence number so we can round robin */
-               best_ni->ni_seq++;
+       if (best_lpn) {
+               /* Select the best NI on the same net as best_lpn chosen
+                * above
+                */
+               best_ni = lnet_find_best_ni_on_spec_net(NULL, peer,
+                                                       best_lpn, md_cpt);
+       }
 
        return best_ni;
 }
 
 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
@@ -2268,18 +2467,13 @@ 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;
        }
 
@@ -2304,14 +2498,15 @@ 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) {
                best_ni =
                  lnet_find_best_ni_on_spec_net(NULL, sd->sd_peer,
                                                sd->sd_best_lpni->lpni_peer_net,
-                                               sd->sd_md_cpt, true);
+                                               sd->sd_md_cpt);
                /* If there is no best_ni we don't have a route */
                if (!best_ni) {
                        CERROR("no path to %s from net %s\n",
@@ -2324,7 +2519,7 @@ 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;
 }
@@ -2343,7 +2538,7 @@ lnet_select_preferred_best_ni(struct lnet_send_data *sd)
 static int
 lnet_handle_any_local_nmr_dst(struct lnet_send_data *sd)
 {
-       int rc;
+       int rc = 0;
 
        /* sd->sd_best_lpni is already set to the final destination */
 
@@ -2360,7 +2555,22 @@ lnet_handle_any_local_nmr_dst(struct lnet_send_data *sd)
                return -EFAULT;
        }
 
-       rc = lnet_select_preferred_best_ni(sd);
+       if (sd->sd_msg->msg_routing) {
+               /* If I'm forwarding this message then I can choose any NI
+                * on the destination peer net
+                */
+               sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL,
+                                                              sd->sd_peer,
+                                                              sd->sd_best_lpni->lpni_peer_net,
+                                                              sd->sd_md_cpt);
+               if (!sd->sd_best_ni) {
+                       CERROR("Unable to forward message to %s. No local NI available\n",
+                              libcfs_nid2str(sd->sd_dst_nid));
+                       rc = -EHOSTUNREACH;
+               }
+       } else
+               rc = lnet_select_preferred_best_ni(sd);
+
        if (!rc)
                rc = lnet_handle_send(sd);
 
@@ -2385,7 +2595,7 @@ lnet_handle_any_mr_dsta(struct lnet_send_data *sd)
                sd->sd_best_ni =
                  lnet_find_best_ni_on_spec_net(NULL, sd->sd_peer,
                                                sd->sd_best_lpni->lpni_peer_net,
-                                               sd->sd_md_cpt, true);
+                                               sd->sd_md_cpt);
 
                if (!sd->sd_best_ni) {
                        /*
@@ -2412,9 +2622,9 @@ 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_best_ni, sd->sd_dst_nid,
-                                            sd->sd_peer,
-                                            sd->sd_best_ni->ni_net->net_id);
+                 lnet_find_best_lpni(sd->sd_best_ni, sd->sd_dst_nid,
+                                     sd->sd_peer,
+                                     sd->sd_best_ni->ni_net->net_id);
 
                /*
                 * if we're successful in selecting a peer_ni on the local
@@ -2557,9 +2767,10 @@ 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
@@ -2574,7 +2785,7 @@ 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;
@@ -2630,12 +2841,14 @@ static int
 lnet_select_pathway(lnet_nid_t src_nid, lnet_nid_t dst_nid,
                    struct lnet_msg *msg, lnet_nid_t rtr_nid)
 {
-       struct lnet_peer_ni     *lpni;
-       struct lnet_peer        *peer;
-       struct lnet_send_data   send_data;
-       int                     cpt, rc;
-       int                     md_cpt;
-       __u32                   send_case = 0;
+       struct lnet_peer_ni *lpni;
+       struct lnet_peer *peer;
+       struct lnet_send_data send_data;
+       int cpt, rc;
+       int md_cpt;
+       __u32 send_case = 0;
+       bool final_hop;
+       bool mr_forwarding_allowed;
 
        memset(&send_data, 0, sizeof(send_data));
 
@@ -2657,20 +2870,13 @@ lnet_select_pathway(lnet_nid_t src_nid, lnet_nid_t dst_nid,
 again:
 
        /*
-        * If we're sending to ourselves then there is no need to go through
-        * any selection. We can shortcut the entire process and send over
-        * lolnd.
-        *
-        * However, we make two exceptions to this rule:
-        * 1. If the src_nid is specified then our API defines that we must send
-        *    via that interface.
-        * 2. Recovery messages must be sent to the lnet_ni that is being
-        *    recovered.
+        * If we're being asked to send to the loopback interface, there
+        * is no need to go through any selection. We can just shortcut
+        * the entire process and send over lolnd
         */
        send_data.sd_msg = msg;
        send_data.sd_cpt = cpt;
-       if (src_nid == LNET_NID_ANY && !msg->msg_recovery &&
-           lnet_nid2ni_locked(dst_nid, cpt)) {
+       if (dst_nid == LNET_NID_LO_0) {
                rc = lnet_handle_lo_send(&send_data);
                lnet_net_unlock(cpt);
                return rc;
@@ -2688,20 +2894,22 @@ 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;
 
        /*
         * 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.
         */
-       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);
@@ -2724,18 +2932,56 @@ again:
        else
                send_case |= REMOTE_DST;
 
+       final_hop = false;
+       if (msg->msg_routing && (send_case & LOCAL_DST))
+               final_hop = true;
+
+       /* Determine whether to allow MR forwarding for this message.
+        * NB: MR forwarding is allowed if the message originator and the
+        * destination are both MR capable, and the destination lpni that was
+        * originally chosen by the originator is unhealthy or down.
+        * We check the MR capability of the destination further below
+        */
+       mr_forwarding_allowed = false;
+       if (final_hop) {
+               struct lnet_peer *src_lp;
+               struct lnet_peer_ni *src_lpni;
+
+               src_lpni = lnet_nid2peerni_locked(msg->msg_hdr.src_nid,
+                                                 LNET_NID_ANY, cpt);
+               /* We don't fail the send if we hit any errors here. We'll just
+                * try to send it via non-multi-rail criteria
+                */
+               if (!IS_ERR(src_lpni)) {
+                       /* Drop ref taken by lnet_nid2peerni_locked() */
+                       lnet_peer_ni_decref_locked(src_lpni);
+                       src_lp = lpni->lpni_peer_net->lpn_peer;
+                       if (lnet_peer_is_multi_rail(src_lp) &&
+                           !lnet_is_peer_ni_alive(lpni))
+                               mr_forwarding_allowed = true;
+
+               }
+               CDEBUG(D_NET, "msg %p MR forwarding %s\n", msg,
+                      mr_forwarding_allowed ? "allowed" : "not allowed");
+       }
+
        /*
-        * if this is a non-MR peer or if we're recovering a peer ni then
-        * let's consider this an NMR case so we can hit the destination
-        * NID.
+        * Deal with the peer as NMR in the following cases:
+        * 1. the peer is NMR
+        * 2. We're trying to recover a specific peer NI
+        * 3. I'm a router sending to the final destination and MR forwarding is
+        *    not allowed for this message (as determined above).
+        *    In this case the source of the message would've
+        *    already selected the final destination so my job
+        *    is to honor the selection.
         */
-       if (!lnet_peer_is_multi_rail(peer) || msg->msg_recovery)
+       if (!lnet_peer_is_multi_rail(peer) || msg->msg_recovery ||
+           (final_hop && !mr_forwarding_allowed))
                send_case |= NMR_DST;
        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 */
@@ -2879,7 +3125,6 @@ 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;
@@ -2888,7 +3133,7 @@ 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]) {
@@ -3031,40 +3276,19 @@ lnet_resend_pending_msgs_locked(struct list_head *resendq, int cpt)
                        lnet_finalize(msg, -EFAULT);
                        lnet_net_lock(cpt);
                } else {
-                       struct lnet_peer *peer;
                        int rc;
-                       lnet_nid_t src_nid = LNET_NID_ANY;
 
-                       /*
-                        * if this message is not being routed and the
-                        * peer is non-MR then we must use the same
-                        * src_nid that was used in the original send.
-                        * Otherwise if we're routing the message (IE
-                        * we're a router) then we can use any of our
-                        * local interfaces. It doesn't matter to the
-                        * final destination.
-                        */
-                       peer = lpni->lpni_peer_net->lpn_peer;
-                       if (!msg->msg_routing &&
-                           !lnet_peer_is_multi_rail(peer))
-                               src_nid = le64_to_cpu(msg->msg_hdr.src_nid);
-
-                       /*
-                        * If we originally specified a src NID, then we
-                        * must attempt to reuse it in the resend as well.
-                        */
-                       if (msg->msg_src_nid_param != LNET_NID_ANY)
-                               src_nid = msg->msg_src_nid_param;
                        lnet_peer_ni_decref_locked(lpni);
 
                        lnet_net_unlock(cpt);
                        CDEBUG(D_NET, "resending %s->%s: %s recovery %d try# %d\n",
-                              libcfs_nid2str(src_nid),
+                              libcfs_nid2str(msg->msg_src_nid_param),
                               libcfs_id2str(msg->msg_target),
                               lnet_msgtyp2str(msg->msg_type),
                               msg->msg_recovery,
                               msg->msg_retry_count);
-                       rc = lnet_send(src_nid, msg, LNET_NID_ANY);
+                       rc = lnet_send(msg->msg_src_nid_param, msg,
+                                      msg->msg_rtr_nid_param);
                        if (rc) {
                                CERROR("Error sending %s to %s: %d\n",
                                       lnet_msgtyp2str(msg->msg_type),
@@ -3116,17 +3340,15 @@ 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;
        lnet_nid_t nid;
        int healthv;
        int rc;
-
-       INIT_LIST_HEAD(&local_queue);
-       INIT_LIST_HEAD(&processed_list);
+       time64_t now;
 
        /*
         * splice the recovery queue on a local queue. We will iterate
@@ -3140,6 +3362,8 @@ lnet_recover_local_nis(void)
                         &local_queue);
        lnet_net_unlock(0);
 
+       now = ktime_get_seconds();
+
        list_for_each_entry_safe(ni, tmp, &local_queue, ni_recovery) {
                /*
                 * if an NI is being deleted or it is now healthy, there
@@ -3173,9 +3397,15 @@ lnet_recover_local_nis(void)
                        ni->ni_recovery_state &= ~LNET_NI_RECOVERY_FAILED;
                }
 
+
                lnet_ni_unlock(ni);
-               lnet_net_unlock(0);
 
+               if (now < ni->ni_next_ping) {
+                       lnet_net_unlock(0);
+                       continue;
+               }
+
+               lnet_net_unlock(0);
 
                CDEBUG(D_NET, "attempting to recover local ni: %s\n",
                       libcfs_nid2str(ni->ni_nid));
@@ -3229,7 +3459,8 @@ lnet_recover_local_nis(void)
                        ev_info->mt_type = MT_TYPE_LOCAL_NI;
                        ev_info->mt_nid = nid;
                        rc = lnet_send_ping(nid, &mdh, LNET_INTERFACES_MIN,
-                                           ev_info, the_lnet.ln_mt_eqh, true);
+                                           ev_info, the_lnet.ln_mt_handler,
+                                           true);
                        /* lookup the nid again */
                        lnet_net_lock(0);
                        ni = lnet_nid2ni_locked(nid, 0);
@@ -3242,30 +3473,20 @@ lnet_recover_local_nis(void)
                                LNetMDUnlink(mdh);
                                continue;
                        }
-                       /*
-                        * Same note as in lnet_recover_peer_nis(). When
-                        * we're sending the ping, the NI is free to be
-                        * deleted or manipulated. By this point it
-                        * could've been added back on the recovery queue,
-                        * and a refcount taken on it.
-                        * So we can't just add it blindly again or we'll
-                        * corrupt the queue. We must check under lock if
-                        * it's not on any list and if not then add it
-                        * to the processed list, which will eventually be
-                        * spliced back on to the recovery queue.
-                        */
+                       ni->ni_ping_count++;
+
                        ni->ni_ping_mdh = mdh;
-                       if (list_empty(&ni->ni_recovery)) {
-                               list_add_tail(&ni->ni_recovery, &processed_list);
-                               lnet_ni_addref_locked(ni, 0);
-                       }
-                       lnet_net_unlock(0);
+                       lnet_ni_add_to_recoveryq_locked(ni, &processed_list,
+                                                       now);
 
-                       lnet_ni_lock(ni);
-                       if (rc)
+                       if (rc) {
+                               lnet_ni_lock(ni);
                                ni->ni_recovery_state &= ~LNET_NI_RECOVERY_PENDING;
-               }
-               lnet_ni_unlock(ni);
+                               lnet_ni_unlock(ni);
+                       }
+                       lnet_net_unlock(0);
+               } else
+                       lnet_ni_unlock(ni);
        }
 
        /*
@@ -3358,11 +3579,9 @@ 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);
@@ -3381,17 +3600,15 @@ 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;
        lnet_nid_t nid;
        int healthv;
        int rc;
-
-       INIT_LIST_HEAD(&local_queue);
-       INIT_LIST_HEAD(&processed_list);
+       time64_t now;
 
        /*
         * Always use cpt 0 for locking across all interactions with
@@ -3402,6 +3619,8 @@ lnet_recover_peer_nis(void)
                         &local_queue);
        lnet_net_unlock(0);
 
+       now = ktime_get_seconds();
+
        list_for_each_entry_safe(lpni, tmp, &local_queue,
                                 lpni_recovery) {
                /*
@@ -3432,6 +3651,12 @@ lnet_recover_peer_nis(void)
                }
 
                spin_unlock(&lpni->lpni_lock);
+
+               if (now < lpni->lpni_next_ping) {
+                       lnet_net_unlock(0);
+                       continue;
+               }
+
                lnet_net_unlock(0);
 
                /*
@@ -3467,7 +3692,8 @@ lnet_recover_peer_nis(void)
                        ev_info->mt_type = MT_TYPE_PEER_NI;
                        ev_info->mt_nid = nid;
                        rc = lnet_send_ping(nid, &mdh, LNET_INTERFACES_MIN,
-                                           ev_info, the_lnet.ln_mt_eqh, true);
+                                           ev_info, the_lnet.ln_mt_handler,
+                                           true);
                        lnet_net_lock(0);
                        /*
                         * lnet_find_peer_ni_locked() grabs a refcount for
@@ -3480,30 +3706,24 @@ lnet_recover_peer_nis(void)
                                continue;
                        }
 
+                       lpni->lpni_ping_count++;
+
                        lpni->lpni_recovery_ping_mdh = mdh;
-                       /*
-                        * While we're unlocked the lpni could've been
-                        * readded on the recovery queue. In this case we
-                        * don't need to add it to the local queue, since
-                        * it's already on there and the thread that added
-                        * it would've incremented the refcount on the
-                        * peer, which means we need to decref the refcount
-                        * that was implicitly grabbed by find_peer_ni_locked.
-                        * Otherwise, if the lpni is still not on
-                        * the recovery queue, then we'll add it to the
-                        * processed list.
-                        */
-                       if (list_empty(&lpni->lpni_recovery))
-                               list_add_tail(&lpni->lpni_recovery, &processed_list);
-                       else
-                               lnet_peer_ni_decref_locked(lpni);
-                       lnet_net_unlock(0);
 
-                       spin_lock(&lpni->lpni_lock);
-                       if (rc)
+                       lnet_peer_ni_add_to_recoveryq_locked(lpni,
+                                                            &processed_list,
+                                                            now);
+                       if (rc) {
+                               spin_lock(&lpni->lpni_lock);
                                lpni->lpni_state &= ~LNET_PEER_NI_RECOVERY_PENDING;
-               }
-               spin_unlock(&lpni->lpni_lock);
+                               spin_unlock(&lpni->lpni_lock);
+                       }
+
+                       /* Drop the ref taken by lnet_find_peer_ni_locked() */
+                       lnet_peer_ni_decref_locked(lpni);
+                       lnet_net_unlock(0);
+               } else
+                       spin_unlock(&lpni->lpni_lock);
        }
 
        list_splice_init(&processed_list, &local_queue);
@@ -3531,8 +3751,6 @@ lnet_monitor_thread(void *arg)
         *  4. Checks if there are any NIs on the remote recovery queue
         *     and pings them.
         */
-       cfs_block_allsigs();
-
        while (the_lnet.ln_mt_state == LNET_MT_STATE_RUNNING) {
                now = ktime_get_real_seconds();
 
@@ -3599,7 +3817,7 @@ lnet_monitor_thread(void *arg)
 int
 lnet_send_ping(lnet_nid_t dest_nid,
               struct lnet_handle_md *mdh, int nnis,
-              void *user_data, struct lnet_handle_eq eqh, bool recovery)
+              void *user_data, lnet_handler_t handler, bool recovery)
 {
        struct lnet_md md = { NULL };
        struct lnet_process_id id;
@@ -3622,11 +3840,11 @@ lnet_send_ping(lnet_nid_t dest_nid,
        md.length    = LNET_PING_INFO_SIZE(nnis);
        md.threshold = 2; /* GET/REPLY */
        md.max_size  = 0;
-       md.options   = LNET_MD_TRUNCATE;
+       md.options   = LNET_MD_TRUNCATE | LNET_MD_TRACK_RESPONSE;
        md.user_ptr  = user_data;
-       md.eq_handle = eqh;
+       md.handler   = handler;
 
-       rc = LNetMDBind(md, LNET_UNLINK, mdh);
+       rc = LNetMDBind(&md, LNET_UNLINK, mdh);
        if (rc) {
                lnet_ping_buffer_decref(pbuf);
                CERROR("Can't bind MD: %d\n", rc);
@@ -3654,7 +3872,7 @@ fail_error:
 
 static void
 lnet_handle_recovery_reply(struct lnet_mt_event_info *ev_info,
-                          int status, bool unlink_event)
+                          int status, bool send, bool unlink_event)
 {
        lnet_nid_t nid = ev_info->mt_nid;
 
@@ -3668,7 +3886,8 @@ lnet_handle_recovery_reply(struct lnet_mt_event_info *ev_info,
                        return;
                }
                lnet_ni_lock(ni);
-               ni->ni_recovery_state &= ~LNET_NI_RECOVERY_PENDING;
+               if (!send || (send && status != 0))
+                       ni->ni_recovery_state &= ~LNET_NI_RECOVERY_PENDING;
                if (status)
                        ni->ni_recovery_state |= LNET_NI_RECOVERY_FAILED;
                lnet_ni_unlock(ni);
@@ -3687,7 +3906,8 @@ lnet_handle_recovery_reply(struct lnet_mt_event_info *ev_info,
                 * In the peer case, it'll naturally be incremented
                 */
                if (!unlink_event)
-                       lnet_inc_healthv(&ni->ni_healthv);
+                       lnet_inc_healthv(&ni->ni_healthv,
+                                        lnet_health_sensitivity);
        } else {
                struct lnet_peer_ni *lpni;
                int cpt;
@@ -3699,7 +3919,8 @@ lnet_handle_recovery_reply(struct lnet_mt_event_info *ev_info,
                        return;
                }
                spin_lock(&lpni->lpni_lock);
-               lpni->lpni_state &= ~LNET_PEER_NI_RECOVERY_PENDING;
+               if (!send || (send && status != 0))
+                       lpni->lpni_state &= ~LNET_PEER_NI_RECOVERY_PENDING;
                if (status)
                        lpni->lpni_state |= LNET_PEER_NI_RECOVERY_FAILED;
                spin_unlock(&lpni->lpni_lock);
@@ -3715,7 +3936,7 @@ lnet_handle_recovery_reply(struct lnet_mt_event_info *ev_info,
 void
 lnet_mt_event_handler(struct lnet_event *event)
 {
-       struct lnet_mt_event_info *ev_info = event->md.user_ptr;
+       struct lnet_mt_event_info *ev_info = event->md_user_ptr;
        struct lnet_ping_buffer *pbuf;
 
        /* TODO: remove assert */
@@ -3732,7 +3953,7 @@ lnet_mt_event_handler(struct lnet_event *event)
                       libcfs_nid2str(ev_info->mt_nid));
                /* fallthrough */
        case LNET_EVENT_REPLY:
-               lnet_handle_recovery_reply(ev_info, event->status,
+               lnet_handle_recovery_reply(ev_info, event->status, false,
                                           event->type == LNET_EVENT_UNLINK);
                break;
        case LNET_EVENT_SEND:
@@ -3740,6 +3961,7 @@ lnet_mt_event_handler(struct lnet_event *event)
                               libcfs_nid2str(ev_info->mt_nid),
                               (event->status) ? "unsuccessfully" :
                               "successfully", event->status);
+               lnet_handle_recovery_reply(ev_info, event->status, true, false);
                break;
        default:
                CERROR("Unexpected event: %d\n", event->type);
@@ -3747,7 +3969,7 @@ lnet_mt_event_handler(struct lnet_event *event)
        }
        if (event->unlinked) {
                LIBCFS_FREE(ev_info, sizeof(*ev_info));
-               pbuf = LNET_PING_INFO_TO_BUFFER(event->md.start);
+               pbuf = LNET_PING_INFO_TO_BUFFER(event->md_start);
                lnet_ping_buffer_decref(pbuf);
        }
 }
@@ -3819,7 +4041,7 @@ clean_thread:
        lnet_clean_local_ni_recoveryq();
        lnet_clean_peer_ni_recoveryq();
        lnet_clean_resendqs();
-       LNetInvalidateEQHandle(&the_lnet.ln_mt_eqh);
+       the_lnet.ln_mt_handler = NULL;
        return rc;
 clean_queues:
        lnet_rsp_tracker_clean();
@@ -4021,8 +4243,8 @@ 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);
@@ -4051,7 +4273,7 @@ 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) {
@@ -4206,68 +4428,6 @@ lnet_msgtyp2str (int type)
        }
 }
 
-void
-lnet_print_hdr(struct lnet_hdr *hdr)
-{
-       struct lnet_process_id src = {
-               .nid = hdr->src_nid,
-               .pid = hdr->src_pid,
-       };
-       struct lnet_process_id dst = {
-               .nid = hdr->dest_nid,
-               .pid = hdr->dest_pid,
-       };
-       char *type_str = lnet_msgtyp2str(hdr->type);
-
-       CWARN("P3 Header at %p of type %s\n", hdr, type_str);
-       CWARN("    From %s\n", libcfs_id2str(src));
-       CWARN("    To   %s\n", libcfs_id2str(dst));
-
-       switch (hdr->type) {
-       default:
-               break;
-
-       case LNET_MSG_PUT:
-               CWARN("    Ptl index %d, ack md %#llx.%#llx, "
-                     "match bits %llu\n",
-                     hdr->msg.put.ptl_index,
-                     hdr->msg.put.ack_wmd.wh_interface_cookie,
-                     hdr->msg.put.ack_wmd.wh_object_cookie,
-                     hdr->msg.put.match_bits);
-               CWARN("    Length %d, offset %d, hdr data %#llx\n",
-                     hdr->payload_length, hdr->msg.put.offset,
-                     hdr->msg.put.hdr_data);
-               break;
-
-       case LNET_MSG_GET:
-               CWARN("    Ptl index %d, return md %#llx.%#llx, "
-                     "match bits %llu\n", hdr->msg.get.ptl_index,
-                     hdr->msg.get.return_wmd.wh_interface_cookie,
-                     hdr->msg.get.return_wmd.wh_object_cookie,
-                     hdr->msg.get.match_bits);
-               CWARN("    Length %d, src offset %d\n",
-                     hdr->msg.get.sink_length,
-                     hdr->msg.get.src_offset);
-               break;
-
-       case LNET_MSG_ACK:
-               CWARN("    dst md %#llx.%#llx, "
-                     "manipulated length %d\n",
-                     hdr->msg.ack.dst_wmd.wh_interface_cookie,
-                     hdr->msg.ack.dst_wmd.wh_object_cookie,
-                     hdr->msg.ack.mlength);
-               break;
-
-       case LNET_MSG_REPLY:
-               CWARN("    dst md %#llx.%#llx, "
-                     "length %d\n",
-                     hdr->msg.reply.dst_wmd.wh_interface_cookie,
-                     hdr->msg.reply.dst_wmd.wh_object_cookie,
-                     hdr->payload_length);
-       }
-
-}
-
 int
 lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
           void *private, int rdma_req)
@@ -4342,11 +4502,7 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
                spin_lock(&ni->ni_net->net_lock);
                ni->ni_net->net_last_alive = ktime_get_real_seconds();
                spin_unlock(&ni->ni_net->net_lock);
-               if (ni->ni_status != NULL &&
-                   ni->ni_status->ns_status == LNET_NI_STATUS_DOWN) {
-                       ni->ni_status->ns_status = LNET_NI_STATUS_UP;
-                       push = true;
-               }
+               push = lnet_ni_set_status_locked(ni, LNET_NI_STATUS_UP);
                lnet_ni_unlock(ni);
        }
 
@@ -4411,68 +4567,13 @@ 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;
        }
 
-       if (lnet_drop_asym_route && for_me &&
-           LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
-               struct lnet_net *net;
-               struct lnet_remotenet *rnet;
-               bool found = true;
-
-               /* we are dealing with a routed message,
-                * so see if route to reach src_nid goes through from_nid
-                */
-               lnet_net_lock(cpt);
-               net = lnet_get_net_locked(LNET_NIDNET(ni->ni_nid));
-               if (!net) {
-                       lnet_net_unlock(cpt);
-                       CERROR("net %s not found\n",
-                              libcfs_net2str(LNET_NIDNET(ni->ni_nid)));
-                       return -EPROTO;
-               }
-
-               rnet = lnet_find_rnet_locked(LNET_NIDNET(src_nid));
-               if (rnet) {
-                       struct lnet_peer *gw = NULL;
-                       struct lnet_peer_ni *lpni = NULL;
-                       struct lnet_route *route;
-
-                       list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
-                               found = false;
-                               gw = route->lr_gateway;
-                               if (route->lr_lnet != net->net_id)
-                                       continue;
-                               /*
-                                * if the nid is one of the gateway's NIDs
-                                * then this is a valid gateway
-                                */
-                               while ((lpni = lnet_get_next_peer_ni_locked(gw,
-                                               NULL, lpni)) != NULL) {
-                                       if (lpni->lpni_nid == from_nid) {
-                                               found = true;
-                                               break;
-                                       }
-                               }
-                       }
-               }
-               lnet_net_unlock(cpt);
-               if (!found) {
-                       /* we would not use from_nid to route a message to
-                        * src_nid
-                        * => asymmetric routing detected but forbidden
-                        */
-                       CERROR("%s, src %s: Dropping asymmetrical route %s\n",
-                              libcfs_nid2str(from_nid),
-                              libcfs_nid2str(src_nid), lnet_msgtyp2str(type));
-                       goto drop;
-               }
-       }
-
        msg = lnet_msg_alloc();
        if (msg == NULL) {
                CERROR("%s, src %s: Dropping %s (out of memory)\n",
@@ -4523,8 +4624,65 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
                goto drop;
        }
 
-       if (the_lnet.ln_routing)
-               lpni->lpni_last_alive = ktime_get_seconds();
+       /* If this message was forwarded to us from a router then we may need
+        * to update router aliveness or check for an asymmetrical route
+        * (or both)
+        */
+       if (((lnet_drop_asym_route && for_me) ||
+            !lpni->lpni_peer_net->lpn_peer->lp_alive) &&
+           LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
+               __u32 src_net_id = LNET_NIDNET(src_nid);
+               struct lnet_peer *gw = lpni->lpni_peer_net->lpn_peer;
+               struct lnet_route *route;
+               bool found = false;
+
+               list_for_each_entry(route, &gw->lp_routes, lr_gwlist) {
+                       if (route->lr_net == src_net_id) {
+                               found = true;
+                               /* If we're transitioning the gateway from
+                                * dead -> alive, and discovery is disabled
+                                * locally or on the gateway, then we need to
+                                * update the cached route aliveness for each
+                                * route to the src_nid's net.
+                                *
+                                * Otherwise, we're only checking for
+                                * symmetrical route, and we can break the
+                                * loop
+                                */
+                               if (!gw->lp_alive &&
+                                   lnet_is_discovery_disabled(gw))
+                                       lnet_set_route_aliveness(route, true);
+                               else
+                                       break;
+                       }
+               }
+               if (lnet_drop_asym_route && for_me && !found) {
+                       lnet_net_unlock(cpt);
+                       /* we would not use from_nid to route a message to
+                        * src_nid
+                        * => asymmetric routing detected but forbidden
+                        */
+                       CERROR("%s, src %s: Dropping asymmetrical route %s\n",
+                              libcfs_nid2str(from_nid),
+                              libcfs_nid2str(src_nid), lnet_msgtyp2str(type));
+                       lnet_msg_free(msg);
+                       goto drop;
+               }
+               if (!gw->lp_alive) {
+                       struct lnet_peer_net *lpn;
+                       struct lnet_peer_ni *lpni2;
+
+                       gw->lp_alive = true;
+                       /* Mark all remote NIs on src_nid's net UP */
+                       lpn = lnet_peer_get_net_locked(gw, src_net_id);
+                       if (lpn)
+                               list_for_each_entry(lpni2, &lpn->lpn_peer_nis,
+                                                   lpni_peer_nis)
+                                       lpni2->lpni_ns_status = LNET_NI_STATUS_UP;
+               }
+       }
+
+       lpni->lpni_last_alive = ktime_get_seconds();
 
        msg->msg_rxpeer = lpni;
        msg->msg_rxni = ni;
@@ -4661,7 +4819,6 @@ 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;
 
        /*
@@ -4681,7 +4838,6 @@ lnet_attach_rsp_tracker(struct lnet_rsp_tracker *rspt, int cpt,
                 * update the deadline on that one.
                 */
                lnet_rspt_free(rspt, cpt);
-               new_entry = false;
        } else {
                /* new md */
                rspt->rspt_mdh = mdh;
@@ -4697,9 +4853,7 @@ 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);
 }
@@ -4775,7 +4929,7 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
                       libcfs_id2str(target));
                return -ENOMEM;
        }
-       msg->msg_vmflush = !!memory_pressure_get();
+       msg->msg_vmflush = !!(current->flags & PF_MEMALLOC);
 
        cpt = lnet_cpt_of_cookie(mdh.cookie);
 
@@ -4801,7 +4955,9 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
                               md->md_me->me_portal);
                lnet_res_unlock(cpt);
 
-               lnet_rspt_free(rspt, cpt);
+               if (rspt)
+                       lnet_rspt_free(rspt, cpt);
+
                lnet_msg_free(msg);
                return -ENOENT;
        }
@@ -4834,8 +4990,11 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
 
        lnet_build_msg_event(msg, LNET_EVENT_SEND);
 
-       if (ack == LNET_ACK_REQ)
+       if (rspt && lnet_response_tracking_enabled(LNET_MSG_PUT,
+                                                  md->md_options))
                lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       else if (rspt)
+               lnet_rspt_free(rspt, cpt);
 
        if (CFS_FAIL_CHECK_ORSET(CFS_FAIL_PTLRPC_OST_BULK_CB2,
                                 CFS_FAIL_ONCE))
@@ -5053,7 +5212,10 @@ LNetGet(lnet_nid_t self, struct lnet_handle_md mdh,
 
        lnet_build_msg_event(msg, LNET_EVENT_SEND);
 
-       lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       if (lnet_response_tracking_enabled(LNET_MSG_GET, md->md_options))
+               lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       else
+               lnet_rspt_free(rspt, cpt);
 
        rc = lnet_send(self, msg, LNET_NID_ANY);
        if (rc < 0) {
@@ -5085,14 +5247,14 @@ EXPORT_SYMBOL(LNetGet);
 int
 LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
 {
-       struct list_head        *e;
+       struct list_head *e;
        struct lnet_ni *ni = NULL;
        struct lnet_remotenet *rnet;
-       __u32                   dstnet = LNET_NIDNET(dstnid);
-       int                     hops;
-       int                     cpt;
-       __u32                   order = 2;
-       struct list_head        *rn_list;
+       __u32 dstnet = LNET_NIDNET(dstnid);
+       int hops;
+       int cpt;
+       __u32 order = 2;
+       struct list_head *rn_list;
 
        /* if !local_nid_dist_zero, I don't return a distance of 0 ever
         * (when lustre sees a distance of 0, it substitutes 0@lo), so I
@@ -5108,7 +5270,7 @@ LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
                        if (srcnidp != NULL)
                                *srcnidp = dstnid;
                        if (orderp != NULL) {
-                               if (LNET_NETTYP(LNET_NIDNET(dstnid)) == LOLND)
+                               if (dstnid == LNET_NID_LO_0)
                                        *orderp = 0;
                                else
                                        *orderp = 1;