X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lnet%2Flnet%2Fpeer.c;h=c6c3d074b79706a7509a66d70146a4fba7e7599f;hp=e9e31474e8cbbfdc6e8cc86b5c68fa6c7db227d9;hb=d92bd22523aa9bb1cdb91ded3d46fb180f68a93c;hpb=e069296630240947f1815e505067fd48033909f7

diff --git a/lnet/lnet/peer.c b/lnet/lnet/peer.c
index e9e3147..c6c3d07 100644
--- a/lnet/lnet/peer.c
+++ b/lnet/lnet/peer.c
@@ -15,17 +15,15 @@
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, 2014, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -37,12 +35,76 @@
 #define DEBUG_SUBSYSTEM S_LNET
 
 #include <lnet/lib-lnet.h>
+#include <uapi/linux/lnet/lnet-dlc.h>
+
+static void
+lnet_peer_remove_from_remote_list(struct lnet_peer_ni *lpni)
+{
+	if (!list_empty(&lpni->lpni_on_remote_peer_ni_list)) {
+		list_del_init(&lpni->lpni_on_remote_peer_ni_list);
+		lnet_peer_ni_decref_locked(lpni);
+	}
+}
+
+void
+lnet_peer_net_added(struct lnet_net *net)
+{
+	struct lnet_peer_ni *lpni, *tmp;
+
+	list_for_each_entry_safe(lpni, tmp, &the_lnet.ln_remote_peer_ni_list,
+				 lpni_on_remote_peer_ni_list) {
+
+		if (LNET_NIDNET(lpni->lpni_nid) == net->net_id) {
+			lpni->lpni_net = net;
+
+			spin_lock(&lpni->lpni_lock);
+			lpni->lpni_txcredits =
+				lpni->lpni_net->net_tunables.lct_peer_tx_credits;
+			lpni->lpni_mintxcredits = lpni->lpni_txcredits;
+			lpni->lpni_rtrcredits =
+				lnet_peer_buffer_credits(lpni->lpni_net);
+			lpni->lpni_minrtrcredits = lpni->lpni_rtrcredits;
+			spin_unlock(&lpni->lpni_lock);
+
+			lnet_peer_remove_from_remote_list(lpni);
+		}
+	}
+}
+
+static void
+lnet_peer_tables_destroy(void)
+{
+	struct lnet_peer_table	*ptable;
+	struct list_head	*hash;
+	int			i;
+	int			j;
+
+	if (!the_lnet.ln_peer_tables)
+		return;
+
+	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
+		hash = ptable->pt_hash;
+		if (!hash) /* not intialized */
+			break;
+
+		LASSERT(list_empty(&ptable->pt_zombie_list));
+
+		ptable->pt_hash = NULL;
+		for (j = 0; j < LNET_PEER_HASH_SIZE; j++)
+			LASSERT(list_empty(&hash[j]));
+
+		LIBCFS_FREE(hash, LNET_PEER_HASH_SIZE * sizeof(*hash));
+	}
+
+	cfs_percpt_free(the_lnet.ln_peer_tables);
+	the_lnet.ln_peer_tables = NULL;
+}
 
 int
 lnet_peer_tables_create(void)
 {
 	struct lnet_peer_table	*ptable;
-	cfs_list_t		*hash;
+	struct list_head	*hash;
 	int			i;
 	int			j;
 
@@ -54,8 +116,6 @@ lnet_peer_tables_create(void)
 	}
 
 	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
-		CFS_INIT_LIST_HEAD(&ptable->pt_deathrow);
-
 		LIBCFS_CPT_ALLOC(hash, lnet_cpt_table(), i,
 				 LNET_PEER_HASH_SIZE * sizeof(*hash));
 		if (hash == NULL) {
@@ -64,135 +124,341 @@ lnet_peer_tables_create(void)
 			return -ENOMEM;
 		}
 
+		spin_lock_init(&ptable->pt_zombie_lock);
+		INIT_LIST_HEAD(&ptable->pt_zombie_list);
+
 		for (j = 0; j < LNET_PEER_HASH_SIZE; j++)
-			CFS_INIT_LIST_HEAD(&hash[j]);
+			INIT_LIST_HEAD(&hash[j]);
 		ptable->pt_hash = hash; /* sign of initialization */
 	}
 
 	return 0;
 }
 
-void
-lnet_peer_tables_destroy(void)
+static struct lnet_peer_ni *
+lnet_peer_ni_alloc(lnet_nid_t nid)
 {
-	struct lnet_peer_table	*ptable;
-	cfs_list_t		*hash;
-	int			i;
-	int			j;
+	struct lnet_peer_ni *lpni;
+	struct lnet_net *net;
+	int cpt;
 
-	if (the_lnet.ln_peer_tables == NULL)
-		return;
+	cpt = lnet_nid_cpt_hash(nid, LNET_CPT_NUMBER);
 
-	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
-		hash = ptable->pt_hash;
-		if (hash == NULL) /* not intialized */
-			break;
+	LIBCFS_CPT_ALLOC(lpni, lnet_cpt_table(), cpt, sizeof(*lpni));
+	if (!lpni)
+		return NULL;
 
-		LASSERT(cfs_list_empty(&ptable->pt_deathrow));
+	INIT_LIST_HEAD(&lpni->lpni_txq);
+	INIT_LIST_HEAD(&lpni->lpni_rtrq);
+	INIT_LIST_HEAD(&lpni->lpni_routes);
+	INIT_LIST_HEAD(&lpni->lpni_hashlist);
+	INIT_LIST_HEAD(&lpni->lpni_on_peer_net_list);
+	INIT_LIST_HEAD(&lpni->lpni_on_remote_peer_ni_list);
 
-		ptable->pt_hash = NULL;
-		for (j = 0; j < LNET_PEER_HASH_SIZE; j++)
-			LASSERT(cfs_list_empty(&hash[j]));
+	spin_lock_init(&lpni->lpni_lock);
 
-		LIBCFS_FREE(hash, LNET_PEER_HASH_SIZE * sizeof(*hash));
+	lpni->lpni_alive = !lnet_peers_start_down(); /* 1 bit!! */
+	lpni->lpni_last_alive = cfs_time_current(); /* assumes alive */
+	lpni->lpni_ping_feats = LNET_PING_FEAT_INVAL;
+	lpni->lpni_nid = nid;
+	lpni->lpni_cpt = cpt;
+	lnet_set_peer_ni_health_locked(lpni, true);
+
+	net = lnet_get_net_locked(LNET_NIDNET(nid));
+	lpni->lpni_net = net;
+	if (net) {
+		lpni->lpni_txcredits = net->net_tunables.lct_peer_tx_credits;
+		lpni->lpni_mintxcredits = lpni->lpni_txcredits;
+		lpni->lpni_rtrcredits = lnet_peer_buffer_credits(net);
+		lpni->lpni_minrtrcredits = lpni->lpni_rtrcredits;
+	} else {
+		/*
+		 * This peer_ni is not on a local network, so we
+		 * cannot add the credits here. In case the net is
+		 * added later, add the peer_ni to the remote peer ni
+		 * list so it can be easily found and revisited.
+		 */
+		/* FIXME: per-net implementation instead? */
+		atomic_inc(&lpni->lpni_refcount);
+		list_add_tail(&lpni->lpni_on_remote_peer_ni_list,
+			      &the_lnet.ln_remote_peer_ni_list);
 	}
 
-	cfs_percpt_free(the_lnet.ln_peer_tables);
-	the_lnet.ln_peer_tables = NULL;
+	/* TODO: update flags */
+
+	return lpni;
 }
 
-void
-lnet_peer_tables_cleanup(void)
+static struct lnet_peer_net *
+lnet_peer_net_alloc(__u32 net_id)
 {
-	struct lnet_peer_table	*ptable;
-	int			i;
-	int			j;
+	struct lnet_peer_net *lpn;
 
-	LASSERT(the_lnet.ln_shutdown);	/* i.e. no new peers */
+	LIBCFS_CPT_ALLOC(lpn, lnet_cpt_table(), CFS_CPT_ANY, sizeof(*lpn));
+	if (!lpn)
+		return NULL;
 
-	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
-		lnet_net_lock(i);
-
-		for (j = 0; j < LNET_PEER_HASH_SIZE; j++) {
-			cfs_list_t *peers = &ptable->pt_hash[j];
-
-			while (!cfs_list_empty(peers)) {
-				lnet_peer_t *lp = cfs_list_entry(peers->next,
-								 lnet_peer_t,
-								 lp_hashlist);
-				cfs_list_del_init(&lp->lp_hashlist);
-				/* lose hash table's ref */
-				lnet_peer_decref_locked(lp);
-			}
+	INIT_LIST_HEAD(&lpn->lpn_on_peer_list);
+	INIT_LIST_HEAD(&lpn->lpn_peer_nis);
+	lpn->lpn_net_id = net_id;
+
+	return lpn;
+}
+
+static struct lnet_peer *
+lnet_peer_alloc(lnet_nid_t nid)
+{
+	struct lnet_peer *lp;
+
+	LIBCFS_CPT_ALLOC(lp, lnet_cpt_table(), CFS_CPT_ANY, sizeof(*lp));
+	if (!lp)
+		return NULL;
+
+	INIT_LIST_HEAD(&lp->lp_on_lnet_peer_list);
+	INIT_LIST_HEAD(&lp->lp_peer_nets);
+	lp->lp_primary_nid = nid;
+
+	/* TODO: update flags */
+
+	return lp;
+}
+
+
+static void
+lnet_try_destroy_peer_hierarchy_locked(struct lnet_peer_ni *lpni)
+{
+	struct lnet_peer_net *peer_net;
+	struct lnet_peer *peer;
+
+	/* TODO: could the below situation happen? accessing an already
+	 * destroyed peer? */
+	if (lpni->lpni_peer_net == NULL ||
+	    lpni->lpni_peer_net->lpn_peer == NULL)
+		return;
+
+	peer_net = lpni->lpni_peer_net;
+	peer = lpni->lpni_peer_net->lpn_peer;
+
+	list_del_init(&lpni->lpni_on_peer_net_list);
+	lpni->lpni_peer_net = NULL;
+
+	/* if peer_net is empty, then remove it from the peer */
+	if (list_empty(&peer_net->lpn_peer_nis)) {
+		list_del_init(&peer_net->lpn_on_peer_list);
+		peer_net->lpn_peer = NULL;
+		LIBCFS_FREE(peer_net, sizeof(*peer_net));
+
+		/* if the peer is empty then remove it from the
+		 * the_lnet.ln_peers */
+		if (list_empty(&peer->lp_peer_nets)) {
+			list_del_init(&peer->lp_on_lnet_peer_list);
+			LIBCFS_FREE(peer, sizeof(*peer));
 		}
+	}
+}
+
+/* called with lnet_net_lock LNET_LOCK_EX held */
+static int
+lnet_peer_ni_del_locked(struct lnet_peer_ni *lpni)
+{
+	struct lnet_peer_table *ptable = NULL;
 
-		lnet_net_unlock(i);
+	/* don't remove a peer_ni if it's also a gateway */
+	if (lpni->lpni_rtr_refcount > 0) {
+		CERROR("Peer NI %s is a gateway. Can not delete it\n",
+		       libcfs_nid2str(lpni->lpni_nid));
+		return -EBUSY;
 	}
 
-	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
-		CFS_LIST_HEAD	(deathrow);
-		lnet_peer_t	*lp;
+	lnet_peer_remove_from_remote_list(lpni);
+
+	/* remove peer ni from the hash list. */
+	list_del_init(&lpni->lpni_hashlist);
+
+	/* decrement the ref count on the peer table */
+	ptable = the_lnet.ln_peer_tables[lpni->lpni_cpt];
+	LASSERT(atomic_read(&ptable->pt_number) > 0);
+	atomic_dec(&ptable->pt_number);
 
-		lnet_net_lock(i);
+	/*
+	 * The peer_ni can no longer be found with a lookup. But there
+	 * can be current users, so keep track of it on the zombie
+	 * list until the reference count has gone to zero.
+	 *
+	 * The last reference may be lost in a place where the
+	 * lnet_net_lock locks only a single cpt, and that cpt may not
+	 * be lpni->lpni_cpt. So the zombie list of this peer_table
+	 * has its own lock.
+	 */
+	spin_lock(&ptable->pt_zombie_lock);
+	list_add(&lpni->lpni_hashlist, &ptable->pt_zombie_list);
+	ptable->pt_zombies++;
+	spin_unlock(&ptable->pt_zombie_lock);
 
-		for (j = 3; ptable->pt_number != 0; j++) {
-			lnet_net_unlock(i);
+	/* no need to keep this peer on the hierarchy anymore */
+	lnet_try_destroy_peer_hierarchy_locked(lpni);
 
-			if ((j & (j - 1)) == 0) {
-				CDEBUG(D_WARNING,
-				       "Waiting for %d peers on peer table\n",
-				       ptable->pt_number);
+	/* decrement reference on peer */
+	lnet_peer_ni_decref_locked(lpni);
+
+	return 0;
+}
+
+void lnet_peer_uninit(void)
+{
+	struct lnet_peer_ni *lpni, *tmp;
+
+	lnet_net_lock(LNET_LOCK_EX);
+
+	/* remove all peer_nis from the remote peer and the hash list */
+	list_for_each_entry_safe(lpni, tmp, &the_lnet.ln_remote_peer_ni_list,
+				 lpni_on_remote_peer_ni_list)
+		lnet_peer_ni_del_locked(lpni);
+
+	lnet_peer_tables_destroy();
+
+	lnet_net_unlock(LNET_LOCK_EX);
+}
+
+static int
+lnet_peer_del_locked(struct lnet_peer *peer)
+{
+	struct lnet_peer_ni *lpni = NULL, *lpni2;
+	int rc = 0, rc2 = 0;
+
+	lpni = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
+	while (lpni != NULL) {
+		lpni2 = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
+		rc = lnet_peer_ni_del_locked(lpni);
+		if (rc != 0)
+			rc2 = rc;
+		lpni = lpni2;
+	}
+
+	return rc2;
+}
+
+static void
+lnet_peer_table_cleanup_locked(struct lnet_net *net,
+			       struct lnet_peer_table *ptable)
+{
+	int			 i;
+	struct lnet_peer_ni	*next;
+	struct lnet_peer_ni	*lpni;
+	struct lnet_peer	*peer;
+
+	for (i = 0; i < LNET_PEER_HASH_SIZE; i++) {
+		list_for_each_entry_safe(lpni, next, &ptable->pt_hash[i],
+					 lpni_hashlist) {
+			if (net != NULL && net != lpni->lpni_net)
+				continue;
+
+			peer = lpni->lpni_peer_net->lpn_peer;
+			if (peer->lp_primary_nid != lpni->lpni_nid) {
+				lnet_peer_ni_del_locked(lpni);
+				continue;
 			}
-			cfs_pause(cfs_time_seconds(1) / 2);
-			lnet_net_lock(i);
+			/*
+			 * Removing the primary NID implies removing
+			 * the entire peer. Advance next beyond any
+			 * peer_ni that belongs to the same peer.
+			 */
+			list_for_each_entry_from(next, &ptable->pt_hash[i],
+						 lpni_hashlist) {
+				if (next->lpni_peer_net->lpn_peer != peer)
+					break;
+			}
+			lnet_peer_del_locked(peer);
 		}
-		cfs_list_splice_init(&ptable->pt_deathrow, &deathrow);
+	}
+}
+
+static void
+lnet_peer_ni_finalize_wait(struct lnet_peer_table *ptable)
+{
+	int	i = 3;
 
-		lnet_net_unlock(i);
+	spin_lock(&ptable->pt_zombie_lock);
+	while (ptable->pt_zombies) {
+		spin_unlock(&ptable->pt_zombie_lock);
 
-		while (!cfs_list_empty(&deathrow)) {
-			lp = cfs_list_entry(deathrow.next,
-					    lnet_peer_t, lp_hashlist);
-			cfs_list_del(&lp->lp_hashlist);
-			LIBCFS_FREE(lp, sizeof(*lp));
+		if (is_power_of_2(i)) {
+			CDEBUG(D_WARNING,
+			       "Waiting for %d zombies on peer table\n",
+			       ptable->pt_zombies);
 		}
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(cfs_time_seconds(1) >> 1);
+		spin_lock(&ptable->pt_zombie_lock);
 	}
+	spin_unlock(&ptable->pt_zombie_lock);
 }
 
-void
-lnet_destroy_peer_locked(lnet_peer_t *lp)
+static void
+lnet_peer_table_del_rtrs_locked(struct lnet_net *net,
+				struct lnet_peer_table *ptable)
 {
-	struct lnet_peer_table *ptable;
+	struct lnet_peer_ni	*lp;
+	struct lnet_peer_ni	*tmp;
+	lnet_nid_t		lpni_nid;
+	int			i;
 
-	LASSERT(lp->lp_refcount == 0);
-	LASSERT(lp->lp_rtr_refcount == 0);
-	LASSERT(cfs_list_empty(&lp->lp_txq));
-	LASSERT(cfs_list_empty(&lp->lp_hashlist));
-	LASSERT(lp->lp_txqnob == 0);
+	for (i = 0; i < LNET_PEER_HASH_SIZE; i++) {
+		list_for_each_entry_safe(lp, tmp, &ptable->pt_hash[i],
+					 lpni_hashlist) {
+			if (net != lp->lpni_net)
+				continue;
 
-	ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
-	LASSERT(ptable->pt_number > 0);
-	ptable->pt_number--;
+			if (lp->lpni_rtr_refcount == 0)
+				continue;
 
-	lnet_ni_decref_locked(lp->lp_ni, lp->lp_cpt);
-	lp->lp_ni = NULL;
+			lpni_nid = lp->lpni_nid;
 
-	cfs_list_add(&lp->lp_hashlist, &ptable->pt_deathrow);
+			lnet_net_unlock(LNET_LOCK_EX);
+			lnet_del_route(LNET_NIDNET(LNET_NID_ANY), lpni_nid);
+			lnet_net_lock(LNET_LOCK_EX);
+		}
+	}
 }
 
-lnet_peer_t *
-lnet_find_peer_locked(struct lnet_peer_table *ptable, lnet_nid_t nid)
+void
+lnet_peer_tables_cleanup(struct lnet_net *net)
 {
-	cfs_list_t	*peers;
-	lnet_peer_t	*lp;
+	int				i;
+	struct lnet_peer_table		*ptable;
 
-	if (the_lnet.ln_shutdown)
-		return NULL;
+	LASSERT(the_lnet.ln_state != LNET_STATE_SHUTDOWN || net != NULL);
+	/* If just deleting the peers for a NI, get rid of any routes these
+	 * peers are gateways for. */
+	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
+		lnet_net_lock(LNET_LOCK_EX);
+		lnet_peer_table_del_rtrs_locked(net, ptable);
+		lnet_net_unlock(LNET_LOCK_EX);
+	}
+
+	/* Start the cleanup process */
+	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
+		lnet_net_lock(LNET_LOCK_EX);
+		lnet_peer_table_cleanup_locked(net, ptable);
+		lnet_net_unlock(LNET_LOCK_EX);
+	}
+
+	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables)
+		lnet_peer_ni_finalize_wait(ptable);
+}
+
+static struct lnet_peer_ni *
+lnet_get_peer_ni_locked(struct lnet_peer_table *ptable, lnet_nid_t nid)
+{
+	struct list_head	*peers;
+	struct lnet_peer_ni	*lp;
+
+	LASSERT(the_lnet.ln_state == LNET_STATE_RUNNING);
 
 	peers = &ptable->pt_hash[lnet_nid2peerhash(nid)];
-	cfs_list_for_each_entry(lp, peers, lp_hashlist) {
-		if (lp->lp_nid == nid) {
-			lnet_peer_addref_locked(lp);
+	list_for_each_entry(lp, peers, lpni_hashlist) {
+		if (lp->lpni_nid == nid) {
+			lnet_peer_ni_addref_locked(lp);
 			return lp;
 		}
 	}
@@ -200,131 +466,759 @@ lnet_find_peer_locked(struct lnet_peer_table *ptable, lnet_nid_t nid)
 	return NULL;
 }
 
+struct lnet_peer_ni *
+lnet_find_peer_ni_locked(lnet_nid_t nid)
+{
+	struct lnet_peer_ni *lpni;
+	struct lnet_peer_table *ptable;
+	int cpt;
+
+	cpt = lnet_nid_cpt_hash(nid, LNET_CPT_NUMBER);
+
+	ptable = the_lnet.ln_peer_tables[cpt];
+	lpni = lnet_get_peer_ni_locked(ptable, nid);
+
+	return lpni;
+}
+
+struct lnet_peer *
+lnet_find_or_create_peer_locked(lnet_nid_t dst_nid, int cpt)
+{
+	struct lnet_peer_ni *lpni;
+	struct lnet_peer *lp;
+
+	lpni = lnet_find_peer_ni_locked(dst_nid);
+	if (!lpni) {
+		lpni = lnet_nid2peerni_locked(dst_nid, cpt);
+		if (IS_ERR(lpni))
+			return ERR_CAST(lpni);
+	}
+
+	lp = lpni->lpni_peer_net->lpn_peer;
+	lnet_peer_ni_decref_locked(lpni);
+
+	return lp;
+}
+
+struct lnet_peer_ni *
+lnet_get_peer_ni_idx_locked(int idx, struct lnet_peer_net **lpn,
+			    struct lnet_peer **lp)
+{
+	struct lnet_peer_ni	*lpni;
+
+	list_for_each_entry((*lp), &the_lnet.ln_peers, lp_on_lnet_peer_list) {
+		list_for_each_entry((*lpn), &((*lp)->lp_peer_nets), lpn_on_peer_list) {
+			list_for_each_entry(lpni, &((*lpn)->lpn_peer_nis),
+					    lpni_on_peer_net_list)
+				if (idx-- == 0)
+					return lpni;
+		}
+	}
+
+	return NULL;
+}
+
+struct lnet_peer_ni *
+lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
+			     struct lnet_peer_net *peer_net,
+			     struct lnet_peer_ni *prev)
+{
+	struct lnet_peer_ni *lpni;
+	struct lnet_peer_net *net = peer_net;
+
+	if (!prev) {
+		if (!net)
+			net = list_entry(peer->lp_peer_nets.next,
+					 struct lnet_peer_net,
+					 lpn_on_peer_list);
+		lpni = list_entry(net->lpn_peer_nis.next, struct lnet_peer_ni,
+				  lpni_on_peer_net_list);
+
+		return lpni;
+	}
+
+	if (prev->lpni_on_peer_net_list.next ==
+	    &prev->lpni_peer_net->lpn_peer_nis) {
+		/*
+		 * if you reached the end of the peer ni list and the peer
+		 * net is specified then there are no more peer nis in that
+		 * net.
+		 */
+		if (net)
+			return NULL;
+
+		/*
+		 * we reached the end of this net ni list. move to the
+		 * next net
+		 */
+		if (prev->lpni_peer_net->lpn_on_peer_list.next ==
+		    &peer->lp_peer_nets)
+			/* no more nets and no more NIs. */
+			return NULL;
+
+		/* get the next net */
+		net = list_entry(prev->lpni_peer_net->lpn_on_peer_list.next,
+				 struct lnet_peer_net,
+				 lpn_on_peer_list);
+		/* get the ni on it */
+		lpni = list_entry(net->lpn_peer_nis.next, struct lnet_peer_ni,
+				  lpni_on_peer_net_list);
+
+		return lpni;
+	}
+
+	/* there are more nis left */
+	lpni = list_entry(prev->lpni_on_peer_net_list.next,
+			  struct lnet_peer_ni, lpni_on_peer_net_list);
+
+	return lpni;
+}
+
+bool
+lnet_peer_is_ni_pref_locked(struct lnet_peer_ni *lpni, struct lnet_ni *ni)
+{
+	int i;
+
+	for (i = 0; i < lpni->lpni_pref_nnids; i++) {
+		if (lpni->lpni_pref_nids[i] == ni->ni_nid)
+			return true;
+	}
+	return false;
+}
+
+lnet_nid_t
+lnet_peer_primary_nid_locked(lnet_nid_t nid)
+{
+	struct lnet_peer_ni *lpni;
+	lnet_nid_t primary_nid = nid;
+
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni) {
+		primary_nid = lpni->lpni_peer_net->lpn_peer->lp_primary_nid;
+		lnet_peer_ni_decref_locked(lpni);
+	}
+
+	return primary_nid;
+}
+
+lnet_nid_t
+LNetPrimaryNID(lnet_nid_t nid)
+{
+	struct lnet_peer_ni *lpni;
+	lnet_nid_t primary_nid = nid;
+	int rc = 0;
+	int cpt;
+
+	cpt = lnet_net_lock_current();
+	lpni = lnet_nid2peerni_locked(nid, cpt);
+	if (IS_ERR(lpni)) {
+		rc = PTR_ERR(lpni);
+		goto out_unlock;
+	}
+	primary_nid = lpni->lpni_peer_net->lpn_peer->lp_primary_nid;
+	lnet_peer_ni_decref_locked(lpni);
+out_unlock:
+	lnet_net_unlock(cpt);
+
+	CDEBUG(D_NET, "NID %s primary NID %s rc %d\n", libcfs_nid2str(nid),
+	       libcfs_nid2str(primary_nid), rc);
+	return primary_nid;
+}
+EXPORT_SYMBOL(LNetPrimaryNID);
+
+struct lnet_peer_net *
+lnet_peer_get_net_locked(struct lnet_peer *peer, __u32 net_id)
+{
+	struct lnet_peer_net *peer_net;
+	list_for_each_entry(peer_net, &peer->lp_peer_nets, lpn_on_peer_list) {
+		if (peer_net->lpn_net_id == net_id)
+			return peer_net;
+	}
+	return NULL;
+}
+
+static int
+lnet_peer_setup_hierarchy(struct lnet_peer *lp, struct lnet_peer_ni *lpni,
+			  lnet_nid_t nid)
+{
+	struct lnet_peer_net *lpn = NULL;
+	struct lnet_peer_table *ptable;
+        __u32 net_id = LNET_NIDNET(nid);
+
+	/*
+	 * Create the peer_ni, peer_net, and peer if they don't exist
+	 * yet.
+	 */
+	if (lp) {
+		lpn = lnet_peer_get_net_locked(lp, net_id);
+	} else {
+		lp = lnet_peer_alloc(nid);
+		if (!lp)
+			goto out_enomem;
+	}
+
+	if (!lpn) {
+		lpn = lnet_peer_net_alloc(net_id);
+		if (!lpn)
+			goto out_maybe_free_lp;
+	}
+
+	if (!lpni) {
+		lpni = lnet_peer_ni_alloc(nid);
+		if (!lpni)
+			goto out_maybe_free_lpn;
+	}
+
+	/* Install the new peer_ni */
+	lnet_net_lock(LNET_LOCK_EX);
+	/* Add peer_ni to global peer table hash, if necessary. */
+	if (list_empty(&lpni->lpni_hashlist)) {
+		ptable = the_lnet.ln_peer_tables[lpni->lpni_cpt];
+		list_add_tail(&lpni->lpni_hashlist,
+			      &ptable->pt_hash[lnet_nid2peerhash(nid)]);
+		ptable->pt_version++;
+		atomic_inc(&ptable->pt_number);
+		atomic_inc(&lpni->lpni_refcount);
+	}
+
+	/* Detach the peer_ni from an existing peer, if necessary. */
+	if (lpni->lpni_peer_net && lpni->lpni_peer_net->lpn_peer != lp)
+		lnet_try_destroy_peer_hierarchy_locked(lpni);
+
+	/* Add peer_ni to peer_net */
+	lpni->lpni_peer_net = lpn;
+	list_add_tail(&lpni->lpni_on_peer_net_list, &lpn->lpn_peer_nis);
+
+	/* Add peer_net to peer */
+	if (!lpn->lpn_peer) {
+		lpn->lpn_peer = lp;
+		list_add_tail(&lpn->lpn_on_peer_list, &lp->lp_peer_nets);
+	}
+
+	/* Add peer to global peer list */
+	if (list_empty(&lp->lp_on_lnet_peer_list))
+		list_add_tail(&lp->lp_on_lnet_peer_list, &the_lnet.ln_peers);
+	lnet_net_unlock(LNET_LOCK_EX);
+
+	return 0;
+
+out_maybe_free_lpn:
+	if (list_empty(&lpn->lpn_on_peer_list))
+		LIBCFS_FREE(lpn, sizeof(*lpn));
+out_maybe_free_lp:
+	if (list_empty(&lp->lp_on_lnet_peer_list))
+		LIBCFS_FREE(lp, sizeof(*lp));
+out_enomem:
+	return -ENOMEM;
+}
+
+static int
+lnet_add_prim_lpni(lnet_nid_t nid)
+{
+	int rc = 0;
+	struct lnet_peer *peer;
+	struct lnet_peer_ni *lpni;
+
+	LASSERT(nid != LNET_NID_ANY);
+
+	/*
+	 * lookup the NID and its peer
+	 *  if the peer doesn't exist, create it.
+	 *  if this is a non-MR peer then change its state to MR and exit.
+	 *  if this is an MR peer and it's a primary NI: NO-OP.
+	 *  if this is an MR peer and it's not a primary NI. Operation not
+	 *     allowed.
+	 *
+	 * The adding and deleting of peer nis is being serialized through
+	 * the api_mutex. So we can look up peers with the mutex locked
+	 * safely. Only when we need to change the ptable, do we need to
+	 * exclusively lock the lnet_net_lock()
+	 */
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (!lpni) {
+		rc = lnet_peer_setup_hierarchy(NULL, NULL, nid);
+		if (rc != 0)
+			return rc;
+		lpni = lnet_find_peer_ni_locked(nid);
+	}
+
+	LASSERT(lpni);
+
+	lnet_peer_ni_decref_locked(lpni);
+
+	peer = lpni->lpni_peer_net->lpn_peer;
+
+	/*
+	 * If we found a lpni with the same nid as the NID we're trying to
+	 * create, then we're trying to create an already existing lpni 
+	 * that belongs to a different peer
+	 */
+	if (peer->lp_primary_nid != nid)
+		return -EEXIST;
+
+	/*
+	 * if we found an lpni that is not a multi-rail, which could occur
+	 * if lpni is already created as a non-mr lpni or we just created
+	 * it, then make sure you indicate that this lpni is a primary mr
+	 * capable peer.
+	 *
+	 * TODO: update flags if necessary
+	 */
+	if (!peer->lp_multi_rail && peer->lp_primary_nid == nid)
+		peer->lp_multi_rail = true;
+
+	return rc;
+}
+
+static int
+lnet_add_peer_ni_to_prim_lpni(lnet_nid_t prim_nid, lnet_nid_t nid)
+{
+	struct lnet_peer *peer, *primary_peer;
+	struct lnet_peer_ni *lpni = NULL, *klpni = NULL;
+
+	LASSERT(prim_nid != LNET_NID_ANY && nid != LNET_NID_ANY);
+
+	/*
+	 * key nid must be created by this point. If not then this
+	 * operation is not permitted
+	 */
+	klpni = lnet_find_peer_ni_locked(prim_nid);
+	if (!klpni)
+		return -ENOENT;
+
+	lnet_peer_ni_decref_locked(klpni);
+
+	primary_peer = klpni->lpni_peer_net->lpn_peer;
+
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni) {
+		lnet_peer_ni_decref_locked(lpni);
+
+		peer = lpni->lpni_peer_net->lpn_peer;
+		/*
+		 * lpni already exists in the system but it belongs to
+		 * a different peer. We can't re-added it
+		 */
+		if (peer->lp_primary_nid != prim_nid && peer->lp_multi_rail) {
+			CERROR("Cannot add NID %s owned by peer %s to peer %s\n",
+			       libcfs_nid2str(lpni->lpni_nid),
+			       libcfs_nid2str(peer->lp_primary_nid),
+			       libcfs_nid2str(prim_nid));
+			return -EEXIST;
+		} else if (peer->lp_primary_nid == prim_nid) {
+			/*
+			 * found a peer_ni that is already part of the
+			 * peer. This is a no-op operation.
+			 */
+			return 0;
+		}
+
+		/*
+		 * TODO: else if (peer->lp_primary_nid != prim_nid &&
+		 *		  !peer->lp_multi_rail)
+		 * peer is not an MR peer and it will be moved in the next
+		 * step to klpni, so update its flags accordingly.
+		 * lnet_move_peer_ni()
+		 */
+
+		/*
+		 * TODO: call lnet_update_peer() from here to update the
+		 * flags. This is the case when the lpni you're trying to
+		 * add is already part of the peer. This could've been
+		 * added by the DD previously, so go ahead and do any
+		 * updates to the state if necessary
+		 */
+
+	}
+
+	/*
+	 * When we get here we either have found an existing lpni, which
+	 * we can switch to the new peer. Or we need to create one and
+	 * add it to the new peer
+	 */
+	return lnet_peer_setup_hierarchy(primary_peer, lpni, nid);
+}
+
+/*
+ * lpni creation initiated due to traffic either sending or receiving.
+ */
+static int
+lnet_peer_ni_traffic_add(lnet_nid_t nid)
+{
+	struct lnet_peer_ni *lpni;
+	int rc = 0;
+
+	if (nid == LNET_NID_ANY)
+		return -EINVAL;
+
+	/* lnet_net_lock is not needed here because ln_api_lock is held */
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni) {
+		/*
+		 * TODO: lnet_update_primary_nid() but not all of it
+		 * only indicate if we're converting this to MR capable
+		 * Can happen due to DD
+		 */
+		lnet_peer_ni_decref_locked(lpni);
+	} else {
+		rc = lnet_peer_setup_hierarchy(NULL, NULL, nid);
+	}
+
+	return rc;
+
+}
+
+static int
+lnet_peer_ni_add_non_mr(lnet_nid_t nid)
+{
+	struct lnet_peer_ni *lpni;
+
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni) {
+		CERROR("Cannot add %s as non-mr when it already exists\n",
+		       libcfs_nid2str(nid));
+		lnet_peer_ni_decref_locked(lpni);
+		return -EEXIST;
+	}
+
+	return lnet_peer_setup_hierarchy(NULL, NULL, nid);
+}
+
+/*
+ * This API handles the following combinations:
+ *	Create a primary NI if only the prim_nid is provided
+ *	Create or add an lpni to a primary NI. Primary NI must've already
+ *	been created
+ *	Create a non-MR peer.
+ */
 int
-lnet_nid2peer_locked(lnet_peer_t **lpp, lnet_nid_t nid, int cpt)
+lnet_add_peer_ni_to_peer(lnet_nid_t prim_nid, lnet_nid_t nid, bool mr)
 {
-	struct lnet_peer_table	*ptable;
-	lnet_peer_t		*lp = NULL;
-	lnet_peer_t		*lp2;
-	int			cpt2;
+	/*
+	 * Caller trying to setup an MR like peer hierarchy but
+	 * specifying it to be non-MR. This is not allowed.
+	 */
+	if (prim_nid != LNET_NID_ANY &&
+	    nid != LNET_NID_ANY && !mr)
+		return -EPERM;
+
+	/* Add the primary NID of a peer */
+	if (prim_nid != LNET_NID_ANY &&
+	    nid == LNET_NID_ANY && mr)
+		return lnet_add_prim_lpni(prim_nid);
+
+	/* Add a NID to an existing peer */
+	if (prim_nid != LNET_NID_ANY &&
+	    nid != LNET_NID_ANY && mr)
+		return lnet_add_peer_ni_to_prim_lpni(prim_nid, nid);
+
+	/* Add a non-MR peer NI */
+	if (((prim_nid != LNET_NID_ANY &&
+	      nid == LNET_NID_ANY) ||
+	     (prim_nid == LNET_NID_ANY &&
+	      nid != LNET_NID_ANY)) && !mr)
+		return lnet_peer_ni_add_non_mr(prim_nid != LNET_NID_ANY ?
+							 prim_nid : nid);
 
-	/* cpt can be LNET_LOCK_EX if it's called from router functions */
-	cpt2 = cpt != LNET_LOCK_EX ? cpt : lnet_cpt_of_nid_locked(nid);
+	return 0;
+}
+
+int
+lnet_del_peer_ni_from_peer(lnet_nid_t prim_nid, lnet_nid_t nid)
+{
+	lnet_nid_t local_nid;
+	struct lnet_peer *peer;
+	struct lnet_peer_ni *lpni;
+	int rc;
 
-	ptable = the_lnet.ln_peer_tables[cpt2];
-	lp = lnet_find_peer_locked(ptable, nid);
-        if (lp != NULL) {
-                *lpp = lp;
-                return 0;
-        }
+	if (prim_nid == LNET_NID_ANY)
+		return -EINVAL;
 
-	if (!cfs_list_empty(&ptable->pt_deathrow)) {
-		lp = cfs_list_entry(ptable->pt_deathrow.next,
-				    lnet_peer_t, lp_hashlist);
-		cfs_list_del(&lp->lp_hashlist);
+	local_nid = (nid != LNET_NID_ANY) ? nid : prim_nid;
+
+	lpni = lnet_find_peer_ni_locked(local_nid);
+	if (!lpni)
+		return -EINVAL;
+	lnet_peer_ni_decref_locked(lpni);
+
+	peer = lpni->lpni_peer_net->lpn_peer;
+	LASSERT(peer != NULL);
+
+	if (peer->lp_primary_nid == lpni->lpni_nid) {
+		/*
+		 * deleting the primary ni is equivalent to deleting the
+		 * entire peer
+		 */
+		lnet_net_lock(LNET_LOCK_EX);
+		rc = lnet_peer_del_locked(peer);
+		lnet_net_unlock(LNET_LOCK_EX);
+
+		return rc;
 	}
 
+	lnet_net_lock(LNET_LOCK_EX);
+	rc = lnet_peer_ni_del_locked(lpni);
+	lnet_net_unlock(LNET_LOCK_EX);
+
+	return rc;
+}
+
+void
+lnet_destroy_peer_ni_locked(struct lnet_peer_ni *lpni)
+{
+	struct lnet_peer_table *ptable;
+
+	LASSERT(atomic_read(&lpni->lpni_refcount) == 0);
+	LASSERT(lpni->lpni_rtr_refcount == 0);
+	LASSERT(list_empty(&lpni->lpni_txq));
+	LASSERT(lpni->lpni_txqnob == 0);
+
+	lpni->lpni_net = NULL;
+
+	/* remove the peer ni from the zombie list */
+	ptable = the_lnet.ln_peer_tables[lpni->lpni_cpt];
+	spin_lock(&ptable->pt_zombie_lock);
+	list_del_init(&lpni->lpni_hashlist);
+	ptable->pt_zombies--;
+	spin_unlock(&ptable->pt_zombie_lock);
+
+	LIBCFS_FREE(lpni, sizeof(*lpni));
+}
+
+struct lnet_peer_ni *
+lnet_nid2peerni_ex(lnet_nid_t nid, int cpt)
+{
+	struct lnet_peer_ni *lpni = NULL;
+	int rc;
+
+	if (the_lnet.ln_state != LNET_STATE_RUNNING)
+		return ERR_PTR(-ESHUTDOWN);
+
+	/*
+	 * find if a peer_ni already exists.
+	 * If so then just return that.
+	 */
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni)
+		return lpni;
+
 	lnet_net_unlock(cpt);
 
-	if (lp != NULL)
-		memset(lp, 0, sizeof(*lp));
-	else
-		LIBCFS_ALLOC(lp, sizeof(*lp));
-
-	if (lp == NULL) {
-                *lpp = NULL;
-                LNET_LOCK();
-                return -ENOMEM;
-        }
-
-	CFS_INIT_LIST_HEAD(&lp->lp_txq);
-        CFS_INIT_LIST_HEAD(&lp->lp_rtrq);
-	CFS_INIT_LIST_HEAD(&lp->lp_routes);
-
-        lp->lp_notify = 0;
-        lp->lp_notifylnd = 0;
-        lp->lp_notifying = 0;
-        lp->lp_alive_count = 0;
-        lp->lp_timestamp = 0;
-        lp->lp_alive = !lnet_peers_start_down(); /* 1 bit!! */
-        lp->lp_last_alive = cfs_time_current(); /* assumes alive */
-        lp->lp_last_query = 0; /* haven't asked NI yet */
-        lp->lp_ping_timestamp = 0;
-	lp->lp_ping_version = LNET_PROTO_PING_UNKNOWN;
-	lp->lp_nid = nid;
-	lp->lp_cpt = cpt2;
-	lp->lp_refcount = 2;                    /* 1 for caller; 1 for hash */
-	lp->lp_rtr_refcount = 0;
+	rc = lnet_peer_ni_traffic_add(nid);
+	if (rc) {
+		lpni = ERR_PTR(rc);
+		goto out_net_relock;
+	}
+
+	lpni = lnet_find_peer_ni_locked(nid);
+	LASSERT(lpni);
 
+out_net_relock:
 	lnet_net_lock(cpt);
 
-	lp2 = lnet_find_peer_locked(ptable, nid);
-	if (lp2 != NULL) {
-		cfs_list_add(&lp->lp_hashlist, &ptable->pt_deathrow);
+	return lpni;
+}
 
-                if (the_lnet.ln_shutdown) {
-                        lnet_peer_decref_locked(lp2);
-                        *lpp = NULL;
-                        return -ESHUTDOWN;
-                }
+struct lnet_peer_ni *
+lnet_nid2peerni_locked(lnet_nid_t nid, int cpt)
+{
+	struct lnet_peer_ni *lpni = NULL;
+	int rc;
 
-                *lpp = lp2;
-                return 0;
-        }
+	if (the_lnet.ln_state != LNET_STATE_RUNNING)
+		return ERR_PTR(-ESHUTDOWN);
 
-	lp->lp_ni = lnet_net2ni_locked(LNET_NIDNET(nid), cpt2);
-	if (lp->lp_ni == NULL) {
-		cfs_list_add(&lp->lp_hashlist, &ptable->pt_deathrow);
+	/*
+	 * find if a peer_ni already exists.
+	 * If so then just return that.
+	 */
+	lpni = lnet_find_peer_ni_locked(nid);
+	if (lpni)
+		return lpni;
 
-                *lpp = NULL;
-                return the_lnet.ln_shutdown ? -ESHUTDOWN : -EHOSTUNREACH;
-        }
+	/*
+	 * Slow path:
+	 * use the lnet_api_mutex to serialize the creation of the peer_ni
+	 * and the creation/deletion of the local ni/net. When a local ni is
+	 * created, if there exists a set of peer_nis on that network,
+	 * they need to be traversed and updated. When a local NI is
+	 * deleted, which could result in a network being deleted, then
+	 * all peer nis on that network need to be removed as well.
+	 *
+	 * Creation through traffic should also be serialized with
+	 * creation through DLC.
+	 */
+	lnet_net_unlock(cpt);
+	mutex_lock(&the_lnet.ln_api_mutex);
+	/*
+	 * Shutdown is only set under the ln_api_lock, so a single
+	 * check here is sufficent.
+	 */
+	if (the_lnet.ln_state != LNET_STATE_RUNNING) {
+		lpni = ERR_PTR(-ESHUTDOWN);
+		goto out_mutex_unlock;
+	}
 
-        lp->lp_txcredits    =
-        lp->lp_mintxcredits = lp->lp_ni->ni_peertxcredits;
-        lp->lp_rtrcredits    =
-        lp->lp_minrtrcredits = lnet_peer_buffer_credits(lp->lp_ni);
+	rc = lnet_peer_ni_traffic_add(nid);
+	if (rc) {
+		lpni = ERR_PTR(rc);
+		goto out_mutex_unlock;
+	}
 
-        /* can't add peers after shutdown starts */
-        LASSERT (!the_lnet.ln_shutdown);
+	lpni = lnet_find_peer_ni_locked(nid);
+	LASSERT(lpni);
 
-	cfs_list_add_tail(&lp->lp_hashlist,
-			  &ptable->pt_hash[lnet_nid2peerhash(nid)]);
-	ptable->pt_version++;
-	ptable->pt_number++;
+out_mutex_unlock:
+	mutex_unlock(&the_lnet.ln_api_mutex);
+	lnet_net_lock(cpt);
 
-	*lpp = lp;
-	return 0;
+	return lpni;
 }
 
 void
 lnet_debug_peer(lnet_nid_t nid)
 {
-	char		*aliveness = "NA";
-	lnet_peer_t	*lp;
-	int		rc;
-	int		cpt;
+	char			*aliveness = "NA";
+	struct lnet_peer_ni	*lp;
+	int			cpt;
 
-	cpt = lnet_cpt_of_nid(nid);
+	cpt = lnet_cpt_of_nid(nid, NULL);
 	lnet_net_lock(cpt);
 
-	rc = lnet_nid2peer_locked(&lp, nid, cpt);
-	if (rc != 0) {
+	lp = lnet_nid2peerni_locked(nid, cpt);
+	if (IS_ERR(lp)) {
 		lnet_net_unlock(cpt);
-                CDEBUG(D_WARNING, "No peer %s\n", libcfs_nid2str(nid));
-                return;
-        }
+		CDEBUG(D_WARNING, "No peer %s\n", libcfs_nid2str(nid));
+		return;
+	}
 
-        if (lnet_isrouter(lp) || lnet_peer_aliveness_enabled(lp))
-                aliveness = lp->lp_alive ? "up" : "down";
+	if (lnet_isrouter(lp) || lnet_peer_aliveness_enabled(lp))
+		aliveness = lp->lpni_alive ? "up" : "down";
 
-        CDEBUG(D_WARNING, "%-24s %4d %5s %5d %5d %5d %5d %5d %ld\n",
-               libcfs_nid2str(lp->lp_nid), lp->lp_refcount,
-               aliveness, lp->lp_ni->ni_peertxcredits,
-               lp->lp_rtrcredits, lp->lp_minrtrcredits,
-               lp->lp_txcredits, lp->lp_mintxcredits, lp->lp_txqnob);
+	CDEBUG(D_WARNING, "%-24s %4d %5s %5d %5d %5d %5d %5d %ld\n",
+	       libcfs_nid2str(lp->lpni_nid), atomic_read(&lp->lpni_refcount),
+	       aliveness, lp->lpni_net->net_tunables.lct_peer_tx_credits,
+	       lp->lpni_rtrcredits, lp->lpni_minrtrcredits,
+	       lp->lpni_txcredits, lp->lpni_mintxcredits, lp->lpni_txqnob);
 
-        lnet_peer_decref_locked(lp);
+	lnet_peer_ni_decref_locked(lp);
 
 	lnet_net_unlock(cpt);
 }
+
+int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
+			  char aliveness[LNET_MAX_STR_LEN],
+			  __u32 *cpt_iter, __u32 *refcount,
+			  __u32 *ni_peer_tx_credits, __u32 *peer_tx_credits,
+			  __u32 *peer_rtr_credits, __u32 *peer_min_rtr_credits,
+			  __u32 *peer_tx_qnob)
+{
+	struct lnet_peer_table		*peer_table;
+	struct lnet_peer_ni		*lp;
+	int				j;
+	int				lncpt;
+	bool				found = false;
+
+	/* get the number of CPTs */
+	lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
+
+	/* if the cpt number to be examined is >= the number of cpts in
+	 * the system then indicate that there are no more cpts to examin
+	 */
+	if (*cpt_iter >= lncpt)
+		return -ENOENT;
+
+	/* get the current table */
+	peer_table = the_lnet.ln_peer_tables[*cpt_iter];
+	/* if the ptable is NULL then there are no more cpts to examine */
+	if (peer_table == NULL)
+		return -ENOENT;
+
+	lnet_net_lock(*cpt_iter);
+
+	for (j = 0; j < LNET_PEER_HASH_SIZE && !found; j++) {
+		struct list_head *peers = &peer_table->pt_hash[j];
+
+		list_for_each_entry(lp, peers, lpni_hashlist) {
+			if (peer_index-- > 0)
+				continue;
+
+			snprintf(aliveness, LNET_MAX_STR_LEN, "NA");
+			if (lnet_isrouter(lp) ||
+				lnet_peer_aliveness_enabled(lp))
+				snprintf(aliveness, LNET_MAX_STR_LEN,
+					 lp->lpni_alive ? "up" : "down");
+
+			*nid = lp->lpni_nid;
+			*refcount = atomic_read(&lp->lpni_refcount);
+			*ni_peer_tx_credits =
+				lp->lpni_net->net_tunables.lct_peer_tx_credits;
+			*peer_tx_credits = lp->lpni_txcredits;
+			*peer_rtr_credits = lp->lpni_rtrcredits;
+			*peer_min_rtr_credits = lp->lpni_mintxcredits;
+			*peer_tx_qnob = lp->lpni_txqnob;
+
+			found = true;
+		}
+
+	}
+	lnet_net_unlock(*cpt_iter);
+
+	*cpt_iter = lncpt;
+
+	return found ? 0 : -ENOENT;
+}
+
+int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
+		       bool *mr,
+		       struct lnet_peer_ni_credit_info __user *peer_ni_info,
+		       struct lnet_ioctl_element_stats __user *peer_ni_stats)
+{
+	struct lnet_peer_ni *lpni = NULL;
+	struct lnet_peer_net *lpn = NULL;
+	struct lnet_peer *lp = NULL;
+	struct lnet_peer_ni_credit_info ni_info;
+	struct lnet_ioctl_element_stats ni_stats;
+	int rc;
+
+	lpni = lnet_get_peer_ni_idx_locked(idx, &lpn, &lp);
+
+	if (!lpni)
+		return -ENOENT;
+
+	*primary_nid = lp->lp_primary_nid;
+	*mr = lp->lp_multi_rail;
+	*nid = lpni->lpni_nid;
+	snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN, "NA");
+	if (lnet_isrouter(lpni) ||
+		lnet_peer_aliveness_enabled(lpni))
+		snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN,
+			 lpni->lpni_alive ? "up" : "down");
+
+	ni_info.cr_refcount = atomic_read(&lpni->lpni_refcount);
+	ni_info.cr_ni_peer_tx_credits = (lpni->lpni_net != NULL) ?
+		lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
+	ni_info.cr_peer_tx_credits = lpni->lpni_txcredits;
+	ni_info.cr_peer_rtr_credits = lpni->lpni_rtrcredits;
+	ni_info.cr_peer_min_rtr_credits = lpni->lpni_minrtrcredits;
+	ni_info.cr_peer_min_tx_credits = lpni->lpni_mintxcredits;
+	ni_info.cr_peer_tx_qnob = lpni->lpni_txqnob;
+	ni_info.cr_ncpt = lpni->lpni_cpt;
+
+	ni_stats.iel_send_count = atomic_read(&lpni->lpni_stats.send_count);
+	ni_stats.iel_recv_count = atomic_read(&lpni->lpni_stats.recv_count);
+	ni_stats.iel_drop_count = atomic_read(&lpni->lpni_stats.drop_count);
+
+	/* If copy_to_user fails */
+	rc = -EFAULT;
+	if (copy_to_user(peer_ni_info, &ni_info, sizeof(ni_info)))
+		goto copy_failed;
+
+	if (copy_to_user(peer_ni_stats, &ni_stats, sizeof(ni_stats)))
+		goto copy_failed;
+
+	rc = 0;
+
+copy_failed:
+	return rc;
+}