+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_net *peer_net)
+{
+ /*
+ * Look at the peer NIs for the destination peer that connect
+ * to the chosen net. If a peer_ni is preferred when using the
+ * best_ni to communicate, we use that one. If there is no
+ * preferred peer_ni, or there are multiple preferred peer_ni,
+ * the available transmit credits are used. If the transmit
+ * 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 lpni_healthv;
+
+ while ((lpni = lnet_get_next_peer_ni_locked(peer, peer_net, lpni))) {
+ /*
+ * if the best_ni we've chosen aleady has this lpni
+ * preferred, then let's use it
+ */
+ if (best_ni) {
+ ni_is_pref = 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);
+ } else {
+ ni_is_pref = false;
+ }
+
+ lpni_healthv = atomic_read(&lpni->lpni_healthv);
+
+ if (best_lpni)
+ CDEBUG(D_NET, "%s c:[%d, %d], s:[%d, %d]\n",
+ libcfs_nid2str(lpni->lpni_nid),
+ lpni->lpni_txcredits, best_lpni_credits,
+ lpni->lpni_seq, best_lpni->lpni_seq);
+
+ /* pick the healthiest peer ni */
+ if (lpni_healthv < best_lpni_healthv) {
+ continue;
+ } else if (lpni_healthv > best_lpni_healthv) {
+ best_lpni_healthv = lpni_healthv;
+ /* 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
+ * it.
+ */
+ continue;
+ } else 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;
+ }
+ }
+
+ best_lpni = lpni;
+ best_lpni_credits = lpni->lpni_txcredits;
+ }
+
+ /* if we still can't find a peer ni then we can't reach it */
+ if (!best_lpni) {
+ __u32 net_id = (peer_net) ? peer_net->lpn_net_id :
+ LNET_NIDNET(dst_nid);
+ CDEBUG(D_NET, "no peer_ni found on peer net %s\n",
+ libcfs_net2str(net_id));
+ return NULL;
+ }
+
+ CDEBUG(D_NET, "sd_best_lpni = %s\n",
+ libcfs_nid2str(best_lpni->lpni_nid));
+
+ return best_lpni;
+}
+
+/*
+ * Prerequisite: the best_ni should already be set in the sd
+ */
+static inline struct lnet_peer_ni *
+lnet_find_best_lpni_on_net(struct lnet_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);
+
+ 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 lnet_select_peer_ni(lni, dst_nid, peer, peer_net);
+}
+
+/* Compare route priorities and hop counts */