/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2017, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/lnet/lib-move.c
 *
 * Data movement routines
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <linux/pagemap.h>

#include <lnet/lib-lnet.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>

static int local_nid_dist_zero = 1;
module_param(local_nid_dist_zero, int, 0444);
MODULE_PARM_DESC(local_nid_dist_zero, "Reserved");

static inline struct lnet_comm_count *
get_stats_counts(struct lnet_element_stats *stats,
		 enum lnet_stats_type stats_type)
{
	switch (stats_type) {
	case LNET_STATS_TYPE_SEND:
		return &stats->el_send_stats;
	case LNET_STATS_TYPE_RECV:
		return &stats->el_recv_stats;
	case LNET_STATS_TYPE_DROP:
		return &stats->el_drop_stats;
	default:
		CERROR("Unknown stats type\n");
	}

	return NULL;
}

void lnet_incr_stats(struct lnet_element_stats *stats,
		     enum lnet_msg_type msg_type,
		     enum lnet_stats_type stats_type)
{
	struct lnet_comm_count *counts = get_stats_counts(stats, stats_type);
	if (!counts)
		return;

	switch (msg_type) {
	case LNET_MSG_ACK:
		atomic_inc(&counts->co_ack_count);
		break;
	case LNET_MSG_PUT:
		atomic_inc(&counts->co_put_count);
		break;
	case LNET_MSG_GET:
		atomic_inc(&counts->co_get_count);
		break;
	case LNET_MSG_REPLY:
		atomic_inc(&counts->co_reply_count);
		break;
	case LNET_MSG_HELLO:
		atomic_inc(&counts->co_hello_count);
		break;
	default:
		CERROR("There is a BUG in the code. Unknown message type\n");
		break;
	}
}

__u32 lnet_sum_stats(struct lnet_element_stats *stats,
		     enum lnet_stats_type stats_type)
{
	struct lnet_comm_count *counts = get_stats_counts(stats, stats_type);
	if (!counts)
		return 0;

	return (atomic_read(&counts->co_ack_count) +
		atomic_read(&counts->co_put_count) +
		atomic_read(&counts->co_get_count) +
		atomic_read(&counts->co_reply_count) +
		atomic_read(&counts->co_hello_count));
}

static inline void assign_stats(struct lnet_ioctl_comm_count *msg_stats,
				struct lnet_comm_count *counts)
{
	msg_stats->ico_get_count = atomic_read(&counts->co_get_count);
	msg_stats->ico_put_count = atomic_read(&counts->co_put_count);
	msg_stats->ico_reply_count = atomic_read(&counts->co_reply_count);
	msg_stats->ico_ack_count = atomic_read(&counts->co_ack_count);
	msg_stats->ico_hello_count = atomic_read(&counts->co_hello_count);
}

void lnet_usr_translate_stats(struct lnet_ioctl_element_msg_stats *msg_stats,
			      struct lnet_element_stats *stats)
{
	struct lnet_comm_count *counts;

	LASSERT(msg_stats);
	LASSERT(stats);

	counts = get_stats_counts(stats, LNET_STATS_TYPE_SEND);
	if (!counts)
		return;
	assign_stats(&msg_stats->im_send_stats, counts);

	counts = get_stats_counts(stats, LNET_STATS_TYPE_RECV);
	if (!counts)
		return;
	assign_stats(&msg_stats->im_recv_stats, counts);

	counts = get_stats_counts(stats, LNET_STATS_TYPE_DROP);
	if (!counts)
		return;
	assign_stats(&msg_stats->im_drop_stats, counts);
}

int
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;

	/* NB: use lnet_net_lock(0) to serialize operations on test peers */
	if (threshold != 0) {
		/* Adding a new entry */
		LIBCFS_ALLOC(tp, sizeof(*tp));
		if (tp == NULL)
			return -ENOMEM;

		tp->tp_nid = nid;
		tp->tp_threshold = threshold;

		lnet_net_lock(0);
		list_add_tail(&tp->tp_list, &the_lnet.ln_test_peers);
		lnet_net_unlock(0);
		return 0;
	}

	/* removing entries */
	INIT_LIST_HEAD(&cull);

	lnet_net_lock(0);

	list_for_each_safe(el, next, &the_lnet.ln_test_peers) {
		tp = list_entry(el, struct lnet_test_peer, tp_list);

		if (tp->tp_threshold == 0 ||	/* needs culling anyway */
		    nid == LNET_NID_ANY ||	/* removing all entries */
		    tp->tp_nid == nid) {	/* matched this one */
			list_del(&tp->tp_list);
			list_add(&tp->tp_list, &cull);
		}
	}

	lnet_net_unlock(0);

	while (!list_empty(&cull)) {
		tp = list_entry(cull.next, struct lnet_test_peer, tp_list);

		list_del(&tp->tp_list);
		LIBCFS_FREE(tp, sizeof(*tp));
	}
	return 0;
}

static int
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);

	/* NB: use lnet_net_lock(0) to serialize operations on test peers */
	lnet_net_lock(0);

	list_for_each_safe(el, next, &the_lnet.ln_test_peers) {
		tp = list_entry(el, struct lnet_test_peer, tp_list);

		if (tp->tp_threshold == 0) {
			/* zombie entry */
			if (outgoing) {
				/* only cull zombies on outgoing tests,
				 * since we may be at interrupt priority on
				 * incoming messages. */
				list_del(&tp->tp_list);
				list_add(&tp->tp_list, &cull);
			}
			continue;
		}

		if (tp->tp_nid == LNET_NID_ANY ||	/* fail every peer */
		    nid == tp->tp_nid) {		/* fail this peer */
			fail = 1;

			if (tp->tp_threshold != LNET_MD_THRESH_INF) {
				tp->tp_threshold--;
				if (outgoing &&
				    tp->tp_threshold == 0) {
					/* see above */
					list_del(&tp->tp_list);
					list_add(&tp->tp_list, &cull);
				}
			}
			break;
		}
	}

	lnet_net_unlock(0);

	while (!list_empty(&cull)) {
		tp = list_entry(cull.next, struct lnet_test_peer, tp_list);
		list_del(&tp->tp_list);

		LIBCFS_FREE(tp, sizeof(*tp));
	}

	return fail;
}

unsigned int
lnet_iov_nob(unsigned int niov, struct kvec *iov)
{
	unsigned int nob = 0;

	LASSERT(niov == 0 || iov != NULL);
	while (niov-- > 0)
		nob += (iov++)->iov_len;

	return (nob);
}
EXPORT_SYMBOL(lnet_iov_nob);

void
lnet_copy_iov2iov(unsigned int ndiov, struct kvec *diov, unsigned int doffset,
		  unsigned int nsiov, struct kvec *siov, unsigned int soffset,
		  unsigned int nob)
{
	/* NB diov, siov are READ-ONLY */
	unsigned int  this_nob;

	if (nob == 0)
		return;

	/* skip complete frags before 'doffset' */
	LASSERT(ndiov > 0);
	while (doffset >= diov->iov_len) {
		doffset -= diov->iov_len;
		diov++;
		ndiov--;
		LASSERT(ndiov > 0);
	}

	/* skip complete frags before 'soffset' */
	LASSERT(nsiov > 0);
	while (soffset >= siov->iov_len) {
		soffset -= siov->iov_len;
		siov++;
		nsiov--;
		LASSERT(nsiov > 0);
	}

	do {
		LASSERT(ndiov > 0);
		LASSERT(nsiov > 0);
		this_nob = MIN(diov->iov_len - doffset,
			       siov->iov_len - soffset);
		this_nob = MIN(this_nob, nob);

		memcpy((char *)diov->iov_base + doffset,
		       (char *)siov->iov_base + soffset, this_nob);
		nob -= this_nob;

		if (diov->iov_len > doffset + this_nob) {
			doffset += this_nob;
		} else {
			diov++;
			ndiov--;
			doffset = 0;
		}

		if (siov->iov_len > soffset + this_nob) {
			soffset += this_nob;
		} else {
			siov++;
			nsiov--;
			soffset = 0;
		}
	} while (nob > 0);
}
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)
{
	unsigned int  nob = 0;

	LASSERT(niov == 0 || kiov != NULL);
	while (niov-- > 0)
		nob += (kiov++)->kiov_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,
		    unsigned int nob)
{
	/* NB diov, siov are READ-ONLY */
	unsigned int	this_nob;
	char	       *daddr = NULL;
	char	       *saddr = NULL;

	if (nob == 0)
		return;

	LASSERT (!in_interrupt ());

	LASSERT (ndiov > 0);
	while (doffset >= diov->kiov_len) {
		doffset -= diov->kiov_len;
		diov++;
		ndiov--;
		LASSERT(ndiov > 0);
	}

	LASSERT(nsiov > 0);
	while (soffset >= siov->kiov_len) {
		soffset -= siov->kiov_len;
		siov++;
		nsiov--;
		LASSERT(nsiov > 0);
	}

	do {
		LASSERT(ndiov > 0);
		LASSERT(nsiov > 0);
		this_nob = MIN(diov->kiov_len - doffset,
			       siov->kiov_len - soffset);
		this_nob = MIN(this_nob, nob);

		if (daddr == NULL)
			daddr = ((char *)kmap(diov->kiov_page)) +
				diov->kiov_offset + doffset;
		if (saddr == NULL)
			saddr = ((char *)kmap(siov->kiov_page)) +
				siov->kiov_offset + soffset;

		/* Vanishing risk of kmap deadlock when mapping 2 pages.
		 * However in practice at least one of the kiovs will be mapped
		 * kernel pages and the map/unmap will be NOOPs */

		memcpy (daddr, saddr, this_nob);
		nob -= this_nob;

		if (diov->kiov_len > doffset + this_nob) {
			daddr += this_nob;
			doffset += this_nob;
		} else {
			kunmap(diov->kiov_page);
			daddr = NULL;
			diov++;
			ndiov--;
			doffset = 0;
		}

		if (siov->kiov_len > soffset + this_nob) {
			saddr += this_nob;
			soffset += this_nob;
		} else {
			kunmap(siov->kiov_page);
			saddr = NULL;
			siov++;
			nsiov--;
			soffset = 0;
		}
	} while (nob > 0);

	if (daddr != NULL)
		kunmap(diov->kiov_page);
	if (saddr != NULL)
		kunmap(siov->kiov_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 nob)
{
	/* NB iov, kiov are READ-ONLY */
	unsigned int	this_nob;
	char	       *addr = NULL;

	if (nob == 0)
		return;

	LASSERT (!in_interrupt ());

	LASSERT (niov > 0);
	while (iovoffset >= iov->iov_len) {
		iovoffset -= iov->iov_len;
		iov++;
		niov--;
		LASSERT(niov > 0);
	}

	LASSERT(nkiov > 0);
	while (kiovoffset >= kiov->kiov_len) {
		kiovoffset -= kiov->kiov_len;
		kiov++;
		nkiov--;
		LASSERT(nkiov > 0);
	}

	do {
		LASSERT(niov > 0);
		LASSERT(nkiov > 0);
		this_nob = MIN(iov->iov_len - iovoffset,
			       kiov->kiov_len - kiovoffset);
		this_nob = MIN(this_nob, nob);

		if (addr == NULL)
			addr = ((char *)kmap(kiov->kiov_page)) +
				kiov->kiov_offset + kiovoffset;

		memcpy((char *)iov->iov_base + iovoffset, addr, this_nob);
		nob -= this_nob;

		if (iov->iov_len > iovoffset + this_nob) {
			iovoffset += this_nob;
		} else {
			iov++;
			niov--;
			iovoffset = 0;
		}

		if (kiov->kiov_len > kiovoffset + this_nob) {
			addr += this_nob;
			kiovoffset += this_nob;
		} else {
			kunmap(kiov->kiov_page);
			addr = NULL;
			kiov++;
			nkiov--;
			kiovoffset = 0;
		}

	} while (nob > 0);

	if (addr != NULL)
		kunmap(kiov->kiov_page);
}
EXPORT_SYMBOL(lnet_copy_kiov2iov);

void
lnet_copy_iov2kiov(unsigned int nkiov, lnet_kiov_t *kiov, unsigned int kiovoffset,
		   unsigned int niov, struct kvec *iov, unsigned int iovoffset,
		   unsigned int nob)
{
	/* NB kiov, iov are READ-ONLY */
	unsigned int	this_nob;
	char	       *addr = NULL;

	if (nob == 0)
		return;

	LASSERT (!in_interrupt ());

	LASSERT (nkiov > 0);
	while (kiovoffset >= kiov->kiov_len) {
		kiovoffset -= kiov->kiov_len;
		kiov++;
		nkiov--;
		LASSERT(nkiov > 0);
	}

	LASSERT(niov > 0);
	while (iovoffset >= iov->iov_len) {
		iovoffset -= iov->iov_len;
		iov++;
		niov--;
		LASSERT(niov > 0);
	}

	do {
		LASSERT(nkiov > 0);
		LASSERT(niov > 0);
		this_nob = MIN(kiov->kiov_len - kiovoffset,
			       iov->iov_len - iovoffset);
		this_nob = MIN(this_nob, nob);

		if (addr == NULL)
			addr = ((char *)kmap(kiov->kiov_page)) +
				kiov->kiov_offset + kiovoffset;

		memcpy (addr, (char *)iov->iov_base + iovoffset, this_nob);
		nob -= this_nob;

		if (kiov->kiov_len > kiovoffset + this_nob) {
			addr += this_nob;
			kiovoffset += this_nob;
		} else {
			kunmap(kiov->kiov_page);
			addr = NULL;
			kiov++;
			nkiov--;
			kiovoffset = 0;
		}

		if (iov->iov_len > iovoffset + this_nob) {
			iovoffset += this_nob;
		} else {
			iov++;
			niov--;
			iovoffset = 0;
		}
	} while (nob > 0);

	if (addr != NULL)
		kunmap(kiov->kiov_page);
}
EXPORT_SYMBOL(lnet_copy_iov2kiov);

int
lnet_extract_kiov(int dst_niov, lnet_kiov_t *dst,
		  int src_niov, lnet_kiov_t *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->kiov_len) {      /* skip initial frags */
		offset -= src->kiov_len;
		src_niov--;
		src++;
		LASSERT(src_niov > 0);
	}

	niov = 1;
	for (;;) {
		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;

		if (len <= frag_len) {
			dst->kiov_len = len;
			LASSERT(dst->kiov_offset + dst->kiov_len <= PAGE_SIZE);
			return niov;
		}

		dst->kiov_len = frag_len;
		LASSERT(dst->kiov_offset + dst->kiov_len <= PAGE_SIZE);

		len -= frag_len;
		dst++;
		src++;
		niov++;
		src_niov--;
		offset = 0;
	}
}
EXPORT_SYMBOL(lnet_extract_kiov);

void
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;
	struct kvec *iov = NULL;
	lnet_kiov_t  *kiov = NULL;
	int	      rc;

	LASSERT (!in_interrupt ());
	LASSERT (mlen == 0 || msg != NULL);

	if (msg != NULL) {
		LASSERT(msg->msg_receiving);
		LASSERT(!msg->msg_sending);
		LASSERT(rlen == msg->msg_len);
		LASSERT(mlen <= msg->msg_len);
		LASSERT(msg->msg_offset == offset);
		LASSERT(msg->msg_wanted == mlen);

		msg->msg_receiving = 0;

		if (mlen != 0) {
			niov = msg->msg_niov;
			iov  = msg->msg_iov;
			kiov = msg->msg_kiov;

			LASSERT (niov > 0);
			LASSERT ((iov == NULL) != (kiov == NULL));
		}
	}

	rc = (ni->ni_net->net_lnd->lnd_recv)(ni, private, msg, delayed,
					     niov, iov, kiov, offset, mlen,
					     rlen);
	if (rc < 0)
		lnet_finalize(msg, rc);
}

static void
lnet_setpayloadbuffer(struct lnet_msg *msg)
{
	struct lnet_libmd *md = msg->msg_md;

	LASSERT(msg->msg_len > 0);
	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;
}

void
lnet_prep_send(struct lnet_msg *msg, int type, struct lnet_process_id target,
	       unsigned int offset, unsigned int len)
{
	msg->msg_type = type;
	msg->msg_target = target;
	msg->msg_len = len;
	msg->msg_offset = offset;

	if (len != 0)
		lnet_setpayloadbuffer(msg);

	memset (&msg->msg_hdr, 0, sizeof (msg->msg_hdr));
	msg->msg_hdr.type           = cpu_to_le32(type);
	/* dest_nid will be overwritten by lnet_select_pathway() */
	msg->msg_hdr.dest_nid       = cpu_to_le64(target.nid);
	msg->msg_hdr.dest_pid       = cpu_to_le32(target.pid);
	/* src_nid will be set later */
	msg->msg_hdr.src_pid        = cpu_to_le32(the_lnet.ln_pid);
	msg->msg_hdr.payload_length = cpu_to_le32(len);
}

static void
lnet_ni_send(struct lnet_ni *ni, struct lnet_msg *msg)
{
	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));

	rc = (ni->ni_net->net_lnd->lnd_send)(ni, priv, msg);
	if (rc < 0)
		lnet_finalize(msg, rc);
}

static int
lnet_ni_eager_recv(struct lnet_ni *ni, struct lnet_msg *msg)
{
	int	rc;

	LASSERT(!msg->msg_sending);
	LASSERT(msg->msg_receiving);
	LASSERT(!msg->msg_rx_ready_delay);
	LASSERT(ni->ni_net->net_lnd->lnd_eager_recv != NULL);

	msg->msg_rx_ready_delay = 1;
	rc = (ni->ni_net->net_lnd->lnd_eager_recv)(ni, msg->msg_private, msg,
						  &msg->msg_private);
	if (rc != 0) {
		CERROR("recv from %s / send to %s aborted: "
		       "eager_recv failed %d\n",
		       libcfs_nid2str(msg->msg_rxpeer->lpni_nid),
		       libcfs_id2str(msg->msg_target), rc);
		LASSERT(rc < 0); /* required by my callers */
	}

	return rc;
}

/*
 * This function can be called from two paths:
 *	1. when sending a message
 *	2. when decommiting a message (lnet_msg_decommit_tx())
 * In both these cases the peer_ni should have it's reference count
 * acquired by the caller and therefore it is safe to drop the spin
 * lock before calling lnd_query()
 */
static void
lnet_ni_query_locked(struct lnet_ni *ni, struct lnet_peer_ni *lp)
{
	time64_t last_alive = 0;
	int cpt = lnet_cpt_of_nid_locked(lp->lpni_nid, ni);

	LASSERT(lnet_peer_aliveness_enabled(lp));
	LASSERT(ni->ni_net->net_lnd->lnd_query != NULL);

	lnet_net_unlock(cpt);
	(ni->ni_net->net_lnd->lnd_query)(ni, lp->lpni_nid, &last_alive);
	lnet_net_lock(cpt);

	lp->lpni_last_query = ktime_get_seconds();

	if (last_alive != 0) /* NI has updated timestamp */
		lp->lpni_last_alive = last_alive;
}

/* NB: always called with lnet_net_lock held */
static inline int
lnet_peer_is_alive(struct lnet_peer_ni *lp, time64_t now)
{
	int alive;
	time64_t deadline;

	LASSERT (lnet_peer_aliveness_enabled(lp));

	/*
	 * Trust lnet_notify() if it has more recent aliveness news, but
	 * ignore the initial assumed death (see lnet_peers_start_down()).
	 */
	spin_lock(&lp->lpni_lock);
	if (!lp->lpni_alive && lp->lpni_alive_count > 0 &&
	    lp->lpni_timestamp >= lp->lpni_last_alive) {
		spin_unlock(&lp->lpni_lock);
		return 0;
	}

	deadline = lp->lpni_last_alive +
		   lp->lpni_net->net_tunables.lct_peer_timeout;
	alive = deadline > now;

	/*
	 * Update obsolete lp_alive except for routers assumed to be dead
	 * initially, because router checker would update aliveness in this
	 * case, and moreover lpni_last_alive at peer creation is assumed.
	 */
	if (alive && !lp->lpni_alive &&
	    !(lnet_isrouter(lp) && lp->lpni_alive_count == 0)) {
		spin_unlock(&lp->lpni_lock);
		lnet_notify_locked(lp, 0, 1, lp->lpni_last_alive);
	} else {
		spin_unlock(&lp->lpni_lock);
	}

	return alive;
}


/* NB: returns 1 when alive, 0 when dead, negative when error;
 *     may drop the lnet_net_lock */
static int
lnet_peer_alive_locked(struct lnet_ni *ni, struct lnet_peer_ni *lp)
{
	time64_t now = ktime_get_seconds();

	if (!lnet_peer_aliveness_enabled(lp))
		return -ENODEV;

	if (lnet_peer_is_alive(lp, now))
		return 1;

	/*
	 * Peer appears dead, but we should avoid frequent NI queries (at
	 * most once per lnet_queryinterval seconds).
	 */
	if (lp->lpni_last_query != 0) {
		static const int lnet_queryinterval = 1;
		time64_t next_query;

		next_query = lp->lpni_last_query + lnet_queryinterval;

		if (now < next_query) {
			if (lp->lpni_alive)
				CWARN("Unexpected aliveness of peer %s: "
				      "%lld < %lld (%d/%d)\n",
				      libcfs_nid2str(lp->lpni_nid),
				      now, next_query,
				      lnet_queryinterval,
				      lp->lpni_net->net_tunables.lct_peer_timeout);
			return 0;
		}
	}

	/* query NI for latest aliveness news */
	lnet_ni_query_locked(ni, lp);

	if (lnet_peer_is_alive(lp, now))
		return 1;

	lnet_notify_locked(lp, 0, 0, lp->lpni_last_alive);
	return 0;
}

/**
 * \param msg The message to be sent.
 * \param do_send True if lnet_ni_send() should be called in this function.
 *	  lnet_send() is going to lnet_net_unlock immediately after this, so
 *	  it sets do_send FALSE and I don't do the unlock/send/lock bit.
 *
 * \retval LNET_CREDIT_OK If \a msg sent or OK to send.
 * \retval LNET_CREDIT_WAIT If \a msg blocked for credit.
 * \retval -EHOSTUNREACH If the next hop of the message appears dead.
 * \retval -ECANCELED If the MD of the message has been unlinked.
 */
static int
lnet_post_send_locked(struct lnet_msg *msg, int do_send)
{
	struct lnet_peer_ni	*lp = msg->msg_txpeer;
	struct lnet_ni		*ni = msg->msg_txni;
	int			cpt = msg->msg_tx_cpt;
	struct lnet_tx_queue	*tq = ni->ni_tx_queues[cpt];

	/* non-lnet_send() callers have checked before */
	LASSERT(!do_send || msg->msg_tx_delayed);
	LASSERT(!msg->msg_receiving);
	LASSERT(msg->msg_tx_committed);

	/* NB 'lp' is always the next hop */
	if ((msg->msg_target.pid & LNET_PID_USERFLAG) == 0 &&
	    lnet_peer_alive_locked(ni, lp) == 0) {
		the_lnet.ln_counters[cpt]->drop_count++;
		the_lnet.ln_counters[cpt]->drop_length += msg->msg_len;
		lnet_net_unlock(cpt);
		if (msg->msg_txpeer)
			lnet_incr_stats(&msg->msg_txpeer->lpni_stats,
					msg->msg_type,
					LNET_STATS_TYPE_DROP);
		if (msg->msg_txni)
			lnet_incr_stats(&msg->msg_txni->ni_stats,
					msg->msg_type,
					LNET_STATS_TYPE_DROP);

		CNETERR("Dropping message for %s: peer not alive\n",
			libcfs_id2str(msg->msg_target));
		if (do_send)
			lnet_finalize(msg, -EHOSTUNREACH);

		lnet_net_lock(cpt);
		return -EHOSTUNREACH;
	}

	if (msg->msg_md != NULL &&
	    (msg->msg_md->md_flags & LNET_MD_FLAG_ABORTED) != 0) {
		lnet_net_unlock(cpt);

		CNETERR("Aborting message for %s: LNetM[DE]Unlink() already "
			"called on the MD/ME.\n",
			libcfs_id2str(msg->msg_target));
		if (do_send)
			lnet_finalize(msg, -ECANCELED);

		lnet_net_lock(cpt);
		return -ECANCELED;
	}

	if (!msg->msg_peertxcredit) {
		spin_lock(&lp->lpni_lock);
		LASSERT((lp->lpni_txcredits < 0) ==
			!list_empty(&lp->lpni_txq));

		msg->msg_peertxcredit = 1;
		lp->lpni_txqnob += msg->msg_len + sizeof(struct lnet_hdr);
		lp->lpni_txcredits--;

		if (lp->lpni_txcredits < lp->lpni_mintxcredits)
			lp->lpni_mintxcredits = lp->lpni_txcredits;

		if (lp->lpni_txcredits < 0) {
			msg->msg_tx_delayed = 1;
			list_add_tail(&msg->msg_list, &lp->lpni_txq);
			spin_unlock(&lp->lpni_lock);
			return LNET_CREDIT_WAIT;
		}
		spin_unlock(&lp->lpni_lock);
	}

	if (!msg->msg_txcredit) {
		LASSERT((tq->tq_credits < 0) ==
			!list_empty(&tq->tq_delayed));

		msg->msg_txcredit = 1;
		tq->tq_credits--;
		atomic_dec(&ni->ni_tx_credits);

		if (tq->tq_credits < tq->tq_credits_min)
			tq->tq_credits_min = tq->tq_credits;

		if (tq->tq_credits < 0) {
			msg->msg_tx_delayed = 1;
			list_add_tail(&msg->msg_list, &tq->tq_delayed);
			return LNET_CREDIT_WAIT;
		}
	}

	if (do_send) {
		lnet_net_unlock(cpt);
		lnet_ni_send(ni, msg);
		lnet_net_lock(cpt);
	}
	return LNET_CREDIT_OK;
}


static struct lnet_rtrbufpool *
lnet_msg2bufpool(struct lnet_msg *msg)
{
	struct lnet_rtrbufpool	*rbp;
	int			cpt;

	LASSERT(msg->msg_rx_committed);

	cpt = msg->msg_rx_cpt;
	rbp = &the_lnet.ln_rtrpools[cpt][0];

	LASSERT(msg->msg_len <= LNET_MTU);
	while (msg->msg_len > (unsigned int)rbp->rbp_npages * PAGE_SIZE) {
		rbp++;
		LASSERT(rbp < &the_lnet.ln_rtrpools[cpt][LNET_NRBPOOLS]);
	}

	return rbp;
}

static int
lnet_post_routed_recv_locked(struct lnet_msg *msg, int do_recv)
{
	/* lnet_parse is going to lnet_net_unlock immediately after this, so it
	 * sets do_recv FALSE and I don't do the unlock/send/lock bit.
	 * I return LNET_CREDIT_WAIT if msg blocked and LNET_CREDIT_OK if
	 * received or OK to receive */
	struct lnet_peer_ni *lp = msg->msg_rxpeer;
	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);
	LASSERT (msg->msg_receiving);
	LASSERT (!msg->msg_sending);

	/* non-lnet_parse callers only receive delayed messages */
	LASSERT(!do_recv || msg->msg_rx_delayed);

	if (!msg->msg_peerrtrcredit) {
		spin_lock(&lp->lpni_lock);
		LASSERT((lp->lpni_rtrcredits < 0) ==
			!list_empty(&lp->lpni_rtrq));

		msg->msg_peerrtrcredit = 1;
		lp->lpni_rtrcredits--;
		if (lp->lpni_rtrcredits < lp->lpni_minrtrcredits)
			lp->lpni_minrtrcredits = lp->lpni_rtrcredits;

		if (lp->lpni_rtrcredits < 0) {
			/* must have checked eager_recv before here */
			LASSERT(msg->msg_rx_ready_delay);
			msg->msg_rx_delayed = 1;
			list_add_tail(&msg->msg_list, &lp->lpni_rtrq);
			spin_unlock(&lp->lpni_lock);
			return LNET_CREDIT_WAIT;
		}
		spin_unlock(&lp->lpni_lock);
	}

	rbp = lnet_msg2bufpool(msg);

	if (!msg->msg_rtrcredit) {
		msg->msg_rtrcredit = 1;
		rbp->rbp_credits--;
		if (rbp->rbp_credits < rbp->rbp_mincredits)
			rbp->rbp_mincredits = rbp->rbp_credits;

		if (rbp->rbp_credits < 0) {
			/* must have checked eager_recv before here */
			LASSERT(msg->msg_rx_ready_delay);
			msg->msg_rx_delayed = 1;
			list_add_tail(&msg->msg_list, &rbp->rbp_msgs);
			return LNET_CREDIT_WAIT;
		}
	}

	LASSERT(!list_empty(&rbp->rbp_bufs));
	rb = list_entry(rbp->rbp_bufs.next, struct lnet_rtrbuf, rb_list);
	list_del(&rb->rb_list);

	msg->msg_niov = rbp->rbp_npages;
	msg->msg_kiov = &rb->rb_kiov[0];

	if (do_recv) {
		int cpt = msg->msg_rx_cpt;

		lnet_net_unlock(cpt);
		lnet_ni_recv(msg->msg_rxni, msg->msg_private, msg, 1,
			     0, msg->msg_len, msg->msg_len);
		lnet_net_lock(cpt);
	}
	return LNET_CREDIT_OK;
}

void
lnet_return_tx_credits_locked(struct lnet_msg *msg)
{
	struct lnet_peer_ni	*txpeer = msg->msg_txpeer;
	struct lnet_ni		*txni = msg->msg_txni;
	struct lnet_msg		*msg2;

	if (msg->msg_txcredit) {
		struct lnet_ni	     *ni = msg->msg_txni;
		struct lnet_tx_queue *tq = ni->ni_tx_queues[msg->msg_tx_cpt];

		/* give back NI txcredits */
		msg->msg_txcredit = 0;

		LASSERT((tq->tq_credits < 0) ==
			!list_empty(&tq->tq_delayed));

		tq->tq_credits++;
		atomic_inc(&ni->ni_tx_credits);
		if (tq->tq_credits <= 0) {
			msg2 = list_entry(tq->tq_delayed.next,
					  struct lnet_msg, msg_list);
			list_del(&msg2->msg_list);

			LASSERT(msg2->msg_txni == ni);
			LASSERT(msg2->msg_tx_delayed);
			LASSERT(msg2->msg_tx_cpt == msg->msg_tx_cpt);

			(void) lnet_post_send_locked(msg2, 1);
		}
	}

	if (msg->msg_peertxcredit) {
		/* give back peer txcredits */
		msg->msg_peertxcredit = 0;

		spin_lock(&txpeer->lpni_lock);
		LASSERT((txpeer->lpni_txcredits < 0) ==
			!list_empty(&txpeer->lpni_txq));

		txpeer->lpni_txqnob -= msg->msg_len + sizeof(struct lnet_hdr);
		LASSERT(txpeer->lpni_txqnob >= 0);

		txpeer->lpni_txcredits++;
		if (txpeer->lpni_txcredits <= 0) {
			int msg2_cpt;

			msg2 = list_entry(txpeer->lpni_txq.next,
					      struct lnet_msg, msg_list);
			list_del(&msg2->msg_list);
			spin_unlock(&txpeer->lpni_lock);

			LASSERT(msg2->msg_txpeer == txpeer);
			LASSERT(msg2->msg_tx_delayed);

			msg2_cpt = msg2->msg_tx_cpt;

			/*
			 * The msg_cpt can be different from the msg2_cpt
			 * so we need to make sure we lock the correct cpt
			 * for msg2.
			 * Once we call lnet_post_send_locked() it is no
			 * longer safe to access msg2, since it could've
			 * been freed by lnet_finalize(), but we still
			 * need to relock the correct cpt, so we cache the
			 * msg2_cpt for the purpose of the check that
			 * follows the call to lnet_pose_send_locked().
			 */
			if (msg2_cpt != msg->msg_tx_cpt) {
				lnet_net_unlock(msg->msg_tx_cpt);
				lnet_net_lock(msg2_cpt);
			}
                        (void) lnet_post_send_locked(msg2, 1);
			if (msg2_cpt != msg->msg_tx_cpt) {
				lnet_net_unlock(msg2_cpt);
				lnet_net_lock(msg->msg_tx_cpt);
			}
                } else {
			spin_unlock(&txpeer->lpni_lock);
		}
        }

	if (txni != NULL) {
		msg->msg_txni = NULL;
		lnet_ni_decref_locked(txni, msg->msg_tx_cpt);
	}

	if (txpeer != NULL) {
		/*
		 * TODO:
		 * Once the patch for the health comes in we need to set
		 * the health of the peer ni to bad when we fail to send
		 * a message.
		 * int status = msg->msg_ev.status;
		 * if (status != 0)
		 *	lnet_set_peer_ni_health_locked(txpeer, false)
		 */
		msg->msg_txpeer = NULL;
		lnet_peer_ni_decref_locked(txpeer);
	}
}

void
lnet_schedule_blocked_locked(struct lnet_rtrbufpool *rbp)
{
	struct lnet_msg	*msg;

	if (list_empty(&rbp->rbp_msgs))
		return;
	msg = list_entry(rbp->rbp_msgs.next,
			 struct lnet_msg, msg_list);
	list_del(&msg->msg_list);

	(void)lnet_post_routed_recv_locked(msg, 1);
}

void
lnet_drop_routed_msgs_locked(struct list_head *list, int cpt)
{
	struct lnet_msg *msg;
	struct lnet_msg *tmp;

	lnet_net_unlock(cpt);

	list_for_each_entry_safe(msg, tmp, list, msg_list) {
		lnet_ni_recv(msg->msg_rxni, msg->msg_private, NULL,
			     0, 0, 0, msg->msg_hdr.payload_length);
		list_del_init(&msg->msg_list);
		lnet_finalize(msg, -ECANCELED);
	}

	lnet_net_lock(cpt);
}

void
lnet_return_rx_credits_locked(struct lnet_msg *msg)
{
	struct lnet_peer_ni *rxpeer = msg->msg_rxpeer;
	struct lnet_ni *rxni = msg->msg_rxni;
	struct lnet_msg	*msg2;

	if (msg->msg_rtrcredit) {
		/* give back global router credits */
		struct lnet_rtrbuf *rb;
		struct lnet_rtrbufpool *rbp;

		/* NB If a msg ever blocks for a buffer in rbp_msgs, it stays
		 * there until it gets one allocated, or aborts the wait
		 * itself */
		LASSERT(msg->msg_kiov != NULL);

		rb = list_entry(msg->msg_kiov, struct lnet_rtrbuf, rb_kiov[0]);
		rbp = rb->rb_pool;

		msg->msg_kiov = NULL;
		msg->msg_rtrcredit = 0;

		LASSERT(rbp == lnet_msg2bufpool(msg));

		LASSERT((rbp->rbp_credits > 0) ==
			!list_empty(&rbp->rbp_bufs));

		/* If routing is now turned off, we just drop this buffer and
		 * don't bother trying to return credits.  */
		if (!the_lnet.ln_routing) {
			lnet_destroy_rtrbuf(rb, rbp->rbp_npages);
			goto routing_off;
		}

		/* It is possible that a user has lowered the desired number of
		 * buffers in this pool.  Make sure we never put back
		 * more buffers than the stated number. */
		if (unlikely(rbp->rbp_credits >= rbp->rbp_req_nbuffers)) {
			/* Discard this buffer so we don't have too
			 * many. */
			lnet_destroy_rtrbuf(rb, rbp->rbp_npages);
			rbp->rbp_nbuffers--;
		} else {
			list_add(&rb->rb_list, &rbp->rbp_bufs);
			rbp->rbp_credits++;
			if (rbp->rbp_credits <= 0)
				lnet_schedule_blocked_locked(rbp);
		}
	}

routing_off:
	if (msg->msg_peerrtrcredit) {
		/* give back peer router credits */
		msg->msg_peerrtrcredit = 0;

		spin_lock(&rxpeer->lpni_lock);
		LASSERT((rxpeer->lpni_rtrcredits < 0) ==
			!list_empty(&rxpeer->lpni_rtrq));

		rxpeer->lpni_rtrcredits++;

		/* 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_splice_init(&rxpeer->lpni_rtrq, &drop);
			spin_unlock(&rxpeer->lpni_lock);
			lnet_drop_routed_msgs_locked(&drop, msg->msg_rx_cpt);
		} else if (rxpeer->lpni_rtrcredits <= 0) {
			msg2 = list_entry(rxpeer->lpni_rtrq.next,
					  struct lnet_msg, msg_list);
			list_del(&msg2->msg_list);
			spin_unlock(&rxpeer->lpni_lock);
			(void) lnet_post_routed_recv_locked(msg2, 1);
		} else {
			spin_unlock(&rxpeer->lpni_lock);
		}
	}
	if (rxni != NULL) {
		msg->msg_rxni = NULL;
		lnet_ni_decref_locked(rxni, msg->msg_rx_cpt);
	}
	if (rxpeer != NULL) {
		msg->msg_rxpeer = NULL;
		lnet_peer_ni_decref_locked(rxpeer);
	}
}

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 int
lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2)
{
	struct lnet_peer_ni *p1 = r1->lr_gateway;
	struct lnet_peer_ni *p2 = r2->lr_gateway;
	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;
	int rc;

	if (r1->lr_priority < r2->lr_priority)
		return 1;

	if (r1->lr_priority > r2->lr_priority)
		return -1;

	if (r1_hops < r2_hops)
		return 1;

	if (r1_hops > r2_hops)
		return -1;

	rc = lnet_compare_peers(p1, p2);
	if (rc)
		return rc;

	if (r1->lr_seq - r2->lr_seq <= 0)
		return 1;

	return -1;
}

static struct lnet_peer_ni *
lnet_find_route_locked(struct lnet_net *net, lnet_nid_t target,
		       lnet_nid_t rtr_nid)
{
	struct lnet_remotenet	*rnet;
	struct lnet_route		*route;
	struct lnet_route		*best_route;
	struct lnet_route		*last_route;
	struct lnet_peer_ni	*lpni_best;
	struct lnet_peer_ni	*lp;
	int			rc;

	/* If @rtr_nid is not LNET_NID_ANY, return the gateway with
	 * rtr_nid nid, otherwise find the best gateway I can use */

	rnet = lnet_find_rnet_locked(LNET_NIDNET(target));
	if (rnet == NULL)
		return NULL;

	lpni_best = NULL;
	best_route = last_route = NULL;
	list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
		lp = route->lr_gateway;

		if (!lnet_is_route_alive(route))
			continue;

		if (net != NULL && lp->lpni_net != net)
			continue;

		if (lp->lpni_nid == rtr_nid) /* it's pre-determined router */
			return lp;

		if (lpni_best == NULL) {
			best_route = last_route = route;
			lpni_best = lp;
			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 < 0)
			continue;

		best_route = route;
		lpni_best = lp;
	}

	/* set sequence number on the best router to the latest sequence + 1
	 * so we can round-robin all routers, it's race and inaccurate but
	 * harmless and functional  */
	if (best_route != NULL)
		best_route->lr_seq = last_route->lr_seq + 1;
	return lpni_best;
}

static struct lnet_ni *
lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *cur_ni,
		 int md_cpt)
{
	struct lnet_ni *ni = NULL, *best_ni = cur_ni;
	unsigned int shortest_distance;
	int best_credits;

	if (best_ni == NULL) {
		shortest_distance = UINT_MAX;
		best_credits = INT_MIN;
	} else {
		shortest_distance = cfs_cpt_distance(lnet_cpt_table(), md_cpt,
						     best_ni->ni_dev_cpt);
		best_credits = atomic_read(&best_ni->ni_tx_credits);
	}

	while ((ni = lnet_get_next_ni_locked(local_net, ni))) {
		unsigned int distance;
		int ni_credits;

		if (!lnet_is_ni_healthy_locked(ni))
			continue;

		ni_credits = atomic_read(&ni->ni_tx_credits);

		/*
		 * calculate the distance from the CPT on which
		 * the message memory is allocated to the CPT of
		 * the NI's physical device
		 */
		distance = cfs_cpt_distance(lnet_cpt_table(),
					    md_cpt,
					    ni->ni_dev_cpt);

		/*
		 * All distances smaller than the NUMA range
		 * are treated equally.
		 */
		if (distance < lnet_numa_range)
			distance = lnet_numa_range;

		/*
		 * Select on shorter distance, then available
		 * credits, then round-robin.
		 */
		if (distance > shortest_distance) {
			continue;
		} else if (distance < shortest_distance) {
			shortest_distance = distance;
		} else if (ni_credits < best_credits) {
			continue;
		} else if (ni_credits == best_credits) {
			if (best_ni && (best_ni)->ni_seq <= ni->ni_seq)
				continue;
		}
		best_ni = ni;
		best_credits = ni_credits;
	}

	return best_ni;
}

/*
 * Traffic to the LNET_RESERVED_PORTAL may not trigger peer discovery,
 * because such traffic is required to perform discovery. We therefore
 * exclude all GET and PUT on that portal. We also exclude all ACK and
 * REPLY traffic, but that is because the portal is not tracked in the
 * message structure for these message types. We could restrict this
 * further by also checking for LNET_PROTO_PING_MATCHBITS.
 */
static bool
lnet_msg_discovery(struct lnet_msg *msg)
{
	if (msg->msg_type == LNET_MSG_PUT) {
		if (msg->msg_hdr.msg.put.ptl_index != LNET_RESERVED_PORTAL)
			return true;
	} else if (msg->msg_type == LNET_MSG_GET) {
		if (msg->msg_hdr.msg.get.ptl_index != LNET_RESERVED_PORTAL)
			return true;
	}
	return false;
}

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_ni		*best_ni;
	struct lnet_peer_ni	*best_lpni;
	struct lnet_peer_ni	*best_gw;
	struct lnet_peer_ni	*lpni;
	struct lnet_peer_ni	*final_dst;
	struct lnet_peer	*peer;
	struct lnet_peer_net	*peer_net;
	struct lnet_net		*local_net;
	int			cpt, cpt2, rc;
	bool			routing;
	bool			routing2;
	bool			ni_is_pref;
	bool			preferred;
	bool			local_found;
	int			best_lpni_credits;
	int			md_cpt;

	/*
	 * get an initial CPT to use for locking. The idea here is not to
	 * serialize the calls to select_pathway, so that as many
	 * operations can run concurrently as possible. To do that we use
	 * the CPT where this call is being executed. Later on when we
	 * determine the CPT to use in lnet_message_commit, we switch the
	 * lock and check if there was any configuration change.  If none,
	 * then we proceed, if there is, then we restart the operation.
	 */
	cpt = lnet_net_lock_current();

	md_cpt = lnet_cpt_of_md(msg->msg_md, msg->msg_offset);
	if (md_cpt == CFS_CPT_ANY)
		md_cpt = cpt;

again:
	best_ni = NULL;
	best_lpni = NULL;
	best_gw = NULL;
	final_dst = NULL;
	local_net = NULL;
	routing = false;
	routing2 = false;
	local_found = false;

	/*
	 * lnet_nid2peerni_locked() is the path that will find an
	 * existing peer_ni, or create one and mark it as having been
	 * created due to network traffic.
	 */
	lpni = lnet_nid2peerni_locked(dst_nid, LNET_NID_ANY, cpt);
	if (IS_ERR(lpni)) {
		lnet_net_unlock(cpt);
		return PTR_ERR(lpni);
	}

	/*
	 * 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
	 */
	if (LNET_NETTYP(LNET_NIDNET(dst_nid)) == LOLND) {
		lnet_peer_ni_decref_locked(lpni);
		best_ni = the_lnet.ln_loni;
		goto send;
	}

	/*
	 * Now that we have a peer_ni, check if we want to discover
	 * the peer. Traffic to the LNET_RESERVED_PORTAL should not
	 * trigger discovery.
	 */
	peer = lpni->lpni_peer_net->lpn_peer;
	if (lnet_msg_discovery(msg) && !lnet_peer_is_uptodate(peer)) {
		rc = lnet_discover_peer_locked(lpni, cpt, false);
		if (rc) {
			lnet_peer_ni_decref_locked(lpni);
			lnet_net_unlock(cpt);
			return rc;
		}
		/* The peer may have changed. */
		peer = lpni->lpni_peer_net->lpn_peer;
		/* queue message and return */
		msg->msg_src_nid_param = src_nid;
		msg->msg_rtr_nid_param = rtr_nid;
		msg->msg_sending = 0;
		list_add_tail(&msg->msg_list, &peer->lp_dc_pendq);
		lnet_peer_ni_decref_locked(lpni);
		lnet_net_unlock(cpt);

		CDEBUG(D_NET, "%s pending discovery\n",
		       libcfs_nid2str(peer->lp_primary_nid));

		return LNET_DC_WAIT;
	}
	lnet_peer_ni_decref_locked(lpni);

	/* If peer is not healthy then can not send anything to it */
	if (!lnet_is_peer_healthy_locked(peer)) {
		lnet_net_unlock(cpt);
		return -EHOSTUNREACH;
	}

	/*
	 * STEP 1: first jab at determining best_ni
	 * if src_nid is explicitly specified, then best_ni is already
	 * pre-determiend for us. Otherwise we need to select the best
	 * one to use later on
	 */
	if (src_nid != LNET_NID_ANY) {
		best_ni = lnet_nid2ni_locked(src_nid, cpt);
		if (!best_ni) {
			lnet_net_unlock(cpt);
			LCONSOLE_WARN("Can't send to %s: src %s is not a "
				      "local nid\n", libcfs_nid2str(dst_nid),
				      libcfs_nid2str(src_nid));
			return -EINVAL;
		}
	}

	if (msg->msg_type == LNET_MSG_REPLY ||
	    msg->msg_type == LNET_MSG_ACK ||
	    !lnet_peer_is_multi_rail(peer) ||
	    best_ni) {
		/*
		 * for replies we want to respond on the same peer_ni we
		 * received the message on if possible. If not, then pick
		 * a peer_ni to send to
		 *
		 * if the peer is non-multi-rail then you want to send to
		 * the dst_nid provided as well.
		 *
		 * If the best_ni has already been determined, IE the
		 * src_nid has been specified, then use the
		 * destination_nid provided as well, since we're
		 * continuing a series of related messages for the same
		 * RPC.
		 *
		 * It is expected to find the lpni using dst_nid, since we
		 * created it earlier.
		 */
		best_lpni = lnet_find_peer_ni_locked(dst_nid);
		if (best_lpni)
			lnet_peer_ni_decref_locked(best_lpni);

		if (best_lpni && !lnet_get_net_locked(LNET_NIDNET(dst_nid))) {
			/*
			 * this lpni is not on a local network so we need
			 * to route this reply.
			 */
			best_gw = lnet_find_route_locked(NULL,
							 best_lpni->lpni_nid,
							 rtr_nid);
			if (best_gw) {
				/*
				* RULE: Each node considers only the next-hop
				*
				* We're going to route the message, so change the peer to
				* the router.
				*/
				LASSERT(best_gw->lpni_peer_net);
				LASSERT(best_gw->lpni_peer_net->lpn_peer);
				peer = best_gw->lpni_peer_net->lpn_peer;

				/*
				* if the router is not multi-rail then use the best_gw
				* found to send the message to
				*/
				if (!lnet_peer_is_multi_rail(peer))
					best_lpni = best_gw;
				else
					best_lpni = NULL;

				routing = true;
			} else {
				best_lpni = NULL;
			}
		} else if (!best_lpni) {
			lnet_net_unlock(cpt);
			CERROR("unable to send msg_type %d to "
			      "originating %s. Destination NID not in DB\n",
			      msg->msg_type, libcfs_nid2str(dst_nid));
			return -EINVAL;
		}
	}

	/*
	 * We must use a consistent source address when sending to a
	 * non-MR peer. However, a non-MR peer can have multiple NIDs
	 * on multiple networks, and we may even need to talk to this
	 * peer on multiple networks -- certain types of
	 * load-balancing configuration do this.
	 *
	 * So we need to pick the NI the peer prefers for this
	 * particular network.
	 */
	if (!lnet_peer_is_multi_rail(peer)) {
		if (!best_lpni) {
			lnet_net_unlock(cpt);
			CERROR("no route to %s\n",
			       libcfs_nid2str(dst_nid));
			return -EHOSTUNREACH;
		}

		/* best ni is already set if src_nid was provided */
		if (!best_ni) {
			/* 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)
					continue;
				LASSERT(lpni->lpni_pref_nnids == 1);
				best_ni = lnet_nid2ni_locked(
						lpni->lpni_pref.nid, cpt);
				break;
			}
		}
		/* if best_ni is still not set just pick one */
		if (!best_ni) {
			best_ni = lnet_net2ni_locked(
				best_lpni->lpni_net->net_id, cpt);
			/* If there is no best_ni we don't have a route */
			if (!best_ni) {
				lnet_net_unlock(cpt);
				CERROR("no path to %s from net %s\n",
					libcfs_nid2str(best_lpni->lpni_nid),
					libcfs_net2str(best_lpni->lpni_net->net_id));
				return -EHOSTUNREACH;
			}
			lpni = list_entry(peer_net->lpn_peer_nis.next,
					struct lnet_peer_ni,
					lpni_peer_nis);
		}
		/* Set preferred NI if necessary. */
		if (lpni->lpni_pref_nnids == 0)
			lnet_peer_ni_set_non_mr_pref_nid(lpni, best_ni->ni_nid);
	}

	/*
	 * if we already found a best_ni because src_nid is specified and
	 * best_lpni because we are replying to a message then just send
	 * the message
	 */
	if (best_ni && best_lpni)
		goto send;

	/*
	 * If we already found a best_ni because src_nid is specified then
	 * pick the peer then send the message
	 */
	if (best_ni)
		goto pick_peer;

	/*
	 * pick the best_ni by going through all the possible networks of
	 * that peer and see which local NI is best suited to talk to that
	 * peer.
	 *
	 * Locally connected networks will always be preferred over
	 * a routed network. If there are only routed paths to the peer,
	 * then the best route is chosen. If all routes are equal then
	 * they are used in round robin.
	 */
	list_for_each_entry(peer_net, &peer->lp_peer_nets, lpn_peer_nets) {
		if (!lnet_is_peer_net_healthy_locked(peer_net))
			continue;

		local_net = lnet_get_net_locked(peer_net->lpn_net_id);
		if (!local_net && !routing && !local_found) {
			struct lnet_peer_ni *net_gw;

			lpni = list_entry(peer_net->lpn_peer_nis.next,
					  struct lnet_peer_ni,
					  lpni_peer_nis);

			net_gw = lnet_find_route_locked(NULL,
							lpni->lpni_nid,
							rtr_nid);
			if (!net_gw)
				continue;

			if (best_gw) {
				/*
				 * lnet_find_route_locked() call
				 * will return the best_Gw on the
				 * lpni->lpni_nid network.
				 * However, best_gw and net_gw can
				 * be on different networks.
				 * Therefore need to compare them
				 * to pick the better of either.
				 */
				if (lnet_compare_peers(best_gw, net_gw) > 0)
					continue;
				if (best_gw->lpni_gw_seq <= net_gw->lpni_gw_seq)
					continue;
			}
			best_gw = net_gw;
			final_dst = lpni;

			routing2 = true;
		} else {
			best_gw = NULL;
			final_dst = NULL;
			routing2 = false;
			local_found = true;
		}

		/*
		 * a gw on this network is found, but there could be
		 * other better gateways on other networks. So don't pick
		 * the best_ni until we determine the best_gw.
		 */
		if (best_gw)
			continue;

		/* if no local_net found continue */
		if (!local_net)
			continue;

		/*
		 * Iterate through the NIs in this local Net and select
		 * the NI to send from. The selection is determined by
		 * these 3 criterion in the following priority:
		 *	1. NUMA
		 *	2. NI available credits
		 *	3. Round Robin
		 */
		best_ni = lnet_get_best_ni(local_net, best_ni, md_cpt);
	}

	if (!best_ni && !best_gw) {
		lnet_net_unlock(cpt);
		LCONSOLE_WARN("No local ni found to send from to %s\n",
			libcfs_nid2str(dst_nid));
		return -EINVAL;
	}

	if (!best_ni) {
		best_ni = lnet_get_best_ni(best_gw->lpni_net, best_ni, md_cpt);
		LASSERT(best_gw && best_ni);

		/*
		 * We're going to route the message, so change the peer to
		 * the router.
		 */
		LASSERT(best_gw->lpni_peer_net);
		LASSERT(best_gw->lpni_peer_net->lpn_peer);
		best_gw->lpni_gw_seq++;
		peer = best_gw->lpni_peer_net->lpn_peer;
	}

	/*
	 * Now that we selected the NI to use increment its sequence
	 * number so the Round Robin algorithm will detect that it has
	 * been used and pick the next NI.
	 */
	best_ni->ni_seq++;

pick_peer:
	/*
	 * At this point the best_ni is on a local network on which
	 * the peer has a peer_ni as well
	 */
	peer_net = lnet_peer_get_net_locked(peer,
					    best_ni->ni_net->net_id);
	/*
	 * peer_net is not available or the src_nid is explicitly defined
	 * and the peer_net for that src_nid is unhealthy. find a route to
	 * the destination nid.
	 */
	if (!peer_net ||
	    (src_nid != LNET_NID_ANY &&
	     !lnet_is_peer_net_healthy_locked(peer_net))) {
		best_gw = lnet_find_route_locked(best_ni->ni_net,
						 dst_nid,
						 rtr_nid);
		/*
		 * if no route is found for that network then
		 * move onto the next peer_ni in the peer
		 */
		if (!best_gw) {
			lnet_net_unlock(cpt);
			LCONSOLE_WARN("No route to peer from %s\n",
				libcfs_nid2str(best_ni->ni_nid));
			return -EHOSTUNREACH;
		}

		CDEBUG(D_NET, "Best route to %s via %s for %s %d\n",
			libcfs_nid2str(dst_nid),
			libcfs_nid2str(best_gw->lpni_nid),
			lnet_msgtyp2str(msg->msg_type), msg->msg_len);

		routing2 = true;
		/*
		 * RULE: Each node considers only the next-hop
		 *
		 * We're going to route the message, so change the peer to
		 * the router.
		 */
		LASSERT(best_gw->lpni_peer_net);
		LASSERT(best_gw->lpni_peer_net->lpn_peer);
		peer = best_gw->lpni_peer_net->lpn_peer;
	} else if (!lnet_is_peer_net_healthy_locked(peer_net)) {
		/*
		 * this peer_net is unhealthy but we still have an opportunity
		 * to find another peer_net that we can use
		 */
		__u32 net_id = peer_net->lpn_net_id;
		LCONSOLE_WARN("peer net %s unhealthy\n",
			      libcfs_net2str(net_id));
		goto again;
	}

	/*
	 * 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.
	 */
	lpni = NULL;
	best_lpni_credits = INT_MIN;
	preferred = false;
	best_lpni = NULL;
	while ((lpni = lnet_get_next_peer_ni_locked(peer, peer_net, lpni))) {
		/*
		 * if this peer ni is not healthy just skip it, no point in
		 * examining it further
		 */
		if (!lnet_is_peer_ni_healthy_locked(lpni))
			continue;
		ni_is_pref = lnet_peer_is_pref_nid_locked(lpni,
							  best_ni->ni_nid);

		/* if this is a preferred peer use it */
		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);
		lnet_net_unlock(cpt);
		LCONSOLE_WARN("no peer_ni found on peer net %s\n",
				libcfs_net2str(net_id));
		return -EHOSTUNREACH;
	}


send:
	/* Shortcut for loopback. */
	if (best_ni == the_lnet.ln_loni) {
		/* No send credit hassles with LOLND */
		lnet_ni_addref_locked(best_ni, cpt);
		msg->msg_hdr.dest_nid = cpu_to_le64(best_ni->ni_nid);
		if (!msg->msg_routing)
			msg->msg_hdr.src_nid = cpu_to_le64(best_ni->ni_nid);
		msg->msg_target.nid = best_ni->ni_nid;
		lnet_msg_commit(msg, cpt);
		msg->msg_txni = best_ni;
		lnet_net_unlock(cpt);

		return LNET_CREDIT_OK;
	}

	routing = routing || routing2;

	/*
	 * Increment sequence number of the peer selected so that we
	 * pick the next one in Round Robin.
	 */
	best_lpni->lpni_seq++;

	/*
	 * grab a reference on the peer_ni so it sticks around even if
	 * we need to drop and relock the lnet_net_lock below.
	 */
	lnet_peer_ni_addref_locked(best_lpni);

	/*
	 * Use lnet_cpt_of_nid() to determine the CPT used to commit the
	 * message. This ensures that we get a CPT that is correct for
	 * the NI when the NI has been restricted to a subset of all CPTs.
	 * If the selected CPT differs from the one currently locked, we
	 * must unlock and relock the lnet_net_lock(), and then check whether
	 * the configuration has changed. We don't have a hold on the best_ni
	 * yet, and it may have vanished.
	 */
	cpt2 = lnet_cpt_of_nid_locked(best_lpni->lpni_nid, best_ni);
	if (cpt != cpt2) {
		__u32 seq = lnet_get_dlc_seq_locked();
		lnet_net_unlock(cpt);
		cpt = cpt2;
		lnet_net_lock(cpt);
		if (seq != lnet_get_dlc_seq_locked()) {
			lnet_peer_ni_decref_locked(best_lpni);
			goto again;
		}
	}

	/*
	 * store the best_lpni in the message right away to avoid having
	 * to do the same operation under different conditions
	 */
	msg->msg_txpeer = best_lpni;
	msg->msg_txni = best_ni;

	/*
	 * grab a reference for the best_ni since now it's in use in this
	 * send. the reference will need to be dropped when the message is
	 * finished in lnet_finalize()
	 */
	lnet_ni_addref_locked(msg->msg_txni, cpt);

	/*
	 * Always set the target.nid to the best peer picked. Either the
	 * nid will be one of the preconfigured NIDs, or the same NID as
	 * what was originally set in the target or it will be the NID of
	 * a router if this message should be routed
	 */
	msg->msg_target.nid = msg->msg_txpeer->lpni_nid;

	/*
	 * lnet_msg_commit assigns the correct cpt to the message, which
	 * is used to decrement the correct refcount on the ni when it's
	 * time to return the credits
	 */
	lnet_msg_commit(msg, cpt);

	/*
	 * If we are routing the message then we don't need to overwrite
	 * the src_nid since it would've been set at the origin. Otherwise
	 * we are the originator so we need to set it.
	 */
	if (!msg->msg_routing)
		msg->msg_hdr.src_nid = cpu_to_le64(msg->msg_txni->ni_nid);

	if (routing) {
		msg->msg_target_is_router = 1;
		msg->msg_target.pid = LNET_PID_LUSTRE;
		/*
		 * since we're routing we want to ensure that the
		 * msg_hdr.dest_nid is set to the final destination. When
		 * the router receives this message it knows how to route
		 * it.
		 */
		msg->msg_hdr.dest_nid =
			cpu_to_le64(final_dst ? final_dst->lpni_nid : dst_nid);
	} else {
		/*
		 * if we're not routing set the dest_nid to the best peer
		 * ni that we picked earlier in the algorithm.
		 */
		msg->msg_hdr.dest_nid = cpu_to_le64(msg->msg_txpeer->lpni_nid);
	}

	rc = lnet_post_send_locked(msg, 0);

	if (!rc)
		CDEBUG(D_NET, "TRACE: %s(%s:%s) -> %s(%s:%s) : %s\n",
		       libcfs_nid2str(msg->msg_hdr.src_nid),
		       libcfs_nid2str(msg->msg_txni->ni_nid),
		       libcfs_nid2str(src_nid),
		       libcfs_nid2str(msg->msg_hdr.dest_nid),
		       libcfs_nid2str(dst_nid),
		       libcfs_nid2str(msg->msg_txpeer->lpni_nid),
		       lnet_msgtyp2str(msg->msg_type));

	lnet_net_unlock(cpt);

	return rc;
}

int
lnet_send(lnet_nid_t src_nid, struct lnet_msg *msg, lnet_nid_t rtr_nid)
{
	lnet_nid_t		dst_nid = msg->msg_target.nid;
	int			rc;

	/*
	 * NB: rtr_nid is set to LNET_NID_ANY for all current use-cases,
	 * but we might want to use pre-determined router for ACK/REPLY
	 * in the future
	 */
	/* NB: ni != NULL == interface pre-determined (ACK/REPLY) */
	LASSERT (msg->msg_txpeer == NULL);
	LASSERT (!msg->msg_sending);
	LASSERT (!msg->msg_target_is_router);
	LASSERT (!msg->msg_receiving);

	msg->msg_sending = 1;

	LASSERT(!msg->msg_tx_committed);

	rc = lnet_select_pathway(src_nid, dst_nid, msg, rtr_nid);
	if (rc < 0)
		return rc;

	if (rc == LNET_CREDIT_OK)
		lnet_ni_send(msg->msg_txni, msg);

	/* rc == LNET_CREDIT_OK or LNET_CREDIT_WAIT or LNET_DC_WAIT */
	return 0;
}

void
lnet_drop_message(struct lnet_ni *ni, int cpt, void *private, unsigned int nob,
		  __u32 msg_type)
{
	lnet_net_lock(cpt);
	lnet_incr_stats(&ni->ni_stats, msg_type, LNET_STATS_TYPE_DROP);
	the_lnet.ln_counters[cpt]->drop_count++;
	the_lnet.ln_counters[cpt]->drop_length += nob;
	lnet_net_unlock(cpt);

	lnet_ni_recv(ni, private, NULL, 0, 0, 0, nob);
}

static void
lnet_recv_put(struct lnet_ni *ni, struct lnet_msg *msg)
{
	struct lnet_hdr	*hdr = &msg->msg_hdr;

	if (msg->msg_wanted != 0)
		lnet_setpayloadbuffer(msg);

	lnet_build_msg_event(msg, LNET_EVENT_PUT);

	/* Must I ACK?	If so I'll grab the ack_wmd out of the header and put
	 * it back into the ACK during lnet_finalize() */
	msg->msg_ack = (!lnet_is_wire_handle_none(&hdr->msg.put.ack_wmd) &&
			(msg->msg_md->md_options & LNET_MD_ACK_DISABLE) == 0);

	lnet_ni_recv(ni, msg->msg_private, msg, msg->msg_rx_delayed,
		     msg->msg_offset, msg->msg_wanted, hdr->payload_length);
}

static int
lnet_parse_put(struct lnet_ni *ni, struct lnet_msg *msg)
{
	struct lnet_hdr		*hdr = &msg->msg_hdr;
	struct lnet_match_info	info;
	int			rc;
	bool			ready_delay;

	/* Convert put fields to host byte order */
	hdr->msg.put.match_bits	= le64_to_cpu(hdr->msg.put.match_bits);
	hdr->msg.put.ptl_index	= le32_to_cpu(hdr->msg.put.ptl_index);
	hdr->msg.put.offset	= le32_to_cpu(hdr->msg.put.offset);

	/* Primary peer NID. */
	info.mi_id.nid	= msg->msg_initiator;
	info.mi_id.pid	= hdr->src_pid;
	info.mi_opc	= LNET_MD_OP_PUT;
	info.mi_portal	= hdr->msg.put.ptl_index;
	info.mi_rlength	= hdr->payload_length;
	info.mi_roffset	= hdr->msg.put.offset;
	info.mi_mbits	= hdr->msg.put.match_bits;
	info.mi_cpt	= lnet_cpt_of_nid(msg->msg_rxpeer->lpni_nid, ni);

	msg->msg_rx_ready_delay = ni->ni_net->net_lnd->lnd_eager_recv == NULL;
	ready_delay = msg->msg_rx_ready_delay;

 again:
	rc = lnet_ptl_match_md(&info, msg);
	switch (rc) {
	default:
		LBUG();

	case LNET_MATCHMD_OK:
		lnet_recv_put(ni, msg);
		return 0;

	case LNET_MATCHMD_NONE:
		if (ready_delay)
			/* no eager_recv or has already called it, should
			 * have been attached on delayed list */
			return 0;

		rc = lnet_ni_eager_recv(ni, msg);
		if (rc == 0) {
			ready_delay = true;
			goto again;
		}
		/* fall through */

	case LNET_MATCHMD_DROP:
		CNETERR("Dropping PUT from %s portal %d match %llu"
			" offset %d length %d: %d\n",
			libcfs_id2str(info.mi_id), info.mi_portal,
			info.mi_mbits, info.mi_roffset, info.mi_rlength, rc);

		return -ENOENT;	/* -ve: OK but no match */
	}
}

static int
lnet_parse_get(struct lnet_ni *ni, struct lnet_msg *msg, int rdma_get)
{
	struct lnet_match_info info;
	struct lnet_hdr *hdr = &msg->msg_hdr;
	struct lnet_process_id source_id;
	struct lnet_handle_wire	reply_wmd;
	int rc;

	/* Convert get fields to host byte order */
	hdr->msg.get.match_bits	  = le64_to_cpu(hdr->msg.get.match_bits);
	hdr->msg.get.ptl_index	  = le32_to_cpu(hdr->msg.get.ptl_index);
	hdr->msg.get.sink_length  = le32_to_cpu(hdr->msg.get.sink_length);
	hdr->msg.get.src_offset	  = le32_to_cpu(hdr->msg.get.src_offset);

	source_id.nid = hdr->src_nid;
	source_id.pid = hdr->src_pid;
	/* Primary peer NID */
	info.mi_id.nid	= msg->msg_initiator;
	info.mi_id.pid	= hdr->src_pid;
	info.mi_opc	= LNET_MD_OP_GET;
	info.mi_portal	= hdr->msg.get.ptl_index;
	info.mi_rlength	= hdr->msg.get.sink_length;
	info.mi_roffset	= hdr->msg.get.src_offset;
	info.mi_mbits	= hdr->msg.get.match_bits;
	info.mi_cpt	= lnet_cpt_of_nid(msg->msg_rxpeer->lpni_nid, ni);

	rc = lnet_ptl_match_md(&info, msg);
	if (rc == LNET_MATCHMD_DROP) {
		CNETERR("Dropping GET from %s portal %d match %llu"
			" offset %d length %d\n",
			libcfs_id2str(info.mi_id), info.mi_portal,
			info.mi_mbits, info.mi_roffset, info.mi_rlength);
		return -ENOENT;	/* -ve: OK but no match */
	}

	LASSERT(rc == LNET_MATCHMD_OK);

	lnet_build_msg_event(msg, LNET_EVENT_GET);

	reply_wmd = hdr->msg.get.return_wmd;

	lnet_prep_send(msg, LNET_MSG_REPLY, source_id,
		       msg->msg_offset, msg->msg_wanted);

	msg->msg_hdr.msg.reply.dst_wmd = reply_wmd;

	if (rdma_get) {
		/* The LND completes the REPLY from her recv procedure */
		lnet_ni_recv(ni, msg->msg_private, msg, 0,
			     msg->msg_offset, msg->msg_len, msg->msg_len);
		return 0;
	}

	lnet_ni_recv(ni, msg->msg_private, NULL, 0, 0, 0, 0);
	msg->msg_receiving = 0;

	rc = lnet_send(ni->ni_nid, msg, LNET_NID_ANY);
	if (rc < 0) {
		/* didn't get as far as lnet_ni_send() */
		CERROR("%s: Unable to send REPLY for GET from %s: %d\n",
		       libcfs_nid2str(ni->ni_nid),
		       libcfs_id2str(info.mi_id), rc);

		lnet_finalize(msg, rc);
	}

	return 0;
}

static int
lnet_parse_reply(struct lnet_ni *ni, struct lnet_msg *msg)
{
	void		 *private = msg->msg_private;
	struct lnet_hdr	 *hdr = &msg->msg_hdr;
	struct lnet_process_id src = {0};
	struct lnet_libmd	 *md;
	int		  rlength;
	int		  mlength;
	int			cpt;

	cpt = lnet_cpt_of_cookie(hdr->msg.reply.dst_wmd.wh_object_cookie);
	lnet_res_lock(cpt);

	src.nid = hdr->src_nid;
	src.pid = hdr->src_pid;

	/* NB handles only looked up by creator (no flips) */
	md = lnet_wire_handle2md(&hdr->msg.reply.dst_wmd);
	if (md == NULL || md->md_threshold == 0 || md->md_me != NULL) {
		CNETERR("%s: Dropping REPLY from %s for %s "
			"MD %#llx.%#llx\n",
			libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
			(md == NULL) ? "invalid" : "inactive",
			hdr->msg.reply.dst_wmd.wh_interface_cookie,
			hdr->msg.reply.dst_wmd.wh_object_cookie);
		if (md != NULL && md->md_me != NULL)
			CERROR("REPLY MD also attached to portal %d\n",
			       md->md_me->me_portal);

		lnet_res_unlock(cpt);
		return -ENOENT;	/* -ve: OK but no match */
	}

	LASSERT(md->md_offset == 0);

	rlength = hdr->payload_length;
	mlength = MIN(rlength, (int)md->md_length);

	if (mlength < rlength &&
	    (md->md_options & LNET_MD_TRUNCATE) == 0) {
		CNETERR("%s: Dropping REPLY from %s length %d "
			"for MD %#llx would overflow (%d)\n",
			libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
			rlength, hdr->msg.reply.dst_wmd.wh_object_cookie,
			mlength);
		lnet_res_unlock(cpt);
		return -ENOENT;	/* -ve: OK but no match */
	}

	CDEBUG(D_NET, "%s: Reply from %s of length %d/%d into md %#llx\n",
	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
	       mlength, rlength, hdr->msg.reply.dst_wmd.wh_object_cookie);

	lnet_msg_attach_md(msg, md, 0, mlength);

	if (mlength != 0)
		lnet_setpayloadbuffer(msg);

	lnet_res_unlock(cpt);

	lnet_build_msg_event(msg, LNET_EVENT_REPLY);

	lnet_ni_recv(ni, private, msg, 0, 0, mlength, rlength);
	return 0;
}

static int
lnet_parse_ack(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			cpt;

	src.nid = hdr->src_nid;
	src.pid = hdr->src_pid;

	/* Convert ack fields to host byte order */
	hdr->msg.ack.match_bits = le64_to_cpu(hdr->msg.ack.match_bits);
	hdr->msg.ack.mlength = le32_to_cpu(hdr->msg.ack.mlength);

	cpt = lnet_cpt_of_cookie(hdr->msg.ack.dst_wmd.wh_object_cookie);
	lnet_res_lock(cpt);

	/* NB handles only looked up by creator (no flips) */
	md = lnet_wire_handle2md(&hdr->msg.ack.dst_wmd);
	if (md == NULL || md->md_threshold == 0 || md->md_me != NULL) {
		/* Don't moan; this is expected */
		CDEBUG(D_NET,
		       "%s: Dropping ACK from %s to %s MD %#llx.%#llx\n",
		       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
		       (md == NULL) ? "invalid" : "inactive",
		       hdr->msg.ack.dst_wmd.wh_interface_cookie,
		       hdr->msg.ack.dst_wmd.wh_object_cookie);
		if (md != NULL && md->md_me != NULL)
			CERROR("Source MD also attached to portal %d\n",
			       md->md_me->me_portal);

		lnet_res_unlock(cpt);
		return -ENOENT;			 /* -ve! */
	}

	CDEBUG(D_NET, "%s: ACK from %s into md %#llx\n",
	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
	       hdr->msg.ack.dst_wmd.wh_object_cookie);

	lnet_msg_attach_md(msg, md, 0, 0);

	lnet_res_unlock(cpt);

	lnet_build_msg_event(msg, LNET_EVENT_ACK);

	lnet_ni_recv(ni, msg->msg_private, msg, 0, 0, 0, msg->msg_len);
	return 0;
}

/**
 * \retval LNET_CREDIT_OK	If \a msg is forwarded
 * \retval LNET_CREDIT_WAIT	If \a msg is blocked because w/o buffer
 * \retval -ve			error code
 */
int
lnet_parse_forward_locked(struct lnet_ni *ni, struct lnet_msg *msg)
{
	int	rc = 0;

	if (!the_lnet.ln_routing)
		return -ECANCELED;

	if (msg->msg_rxpeer->lpni_rtrcredits <= 0 ||
	    lnet_msg2bufpool(msg)->rbp_credits <= 0) {
		if (ni->ni_net->net_lnd->lnd_eager_recv == NULL) {
			msg->msg_rx_ready_delay = 1;
		} else {
			lnet_net_unlock(msg->msg_rx_cpt);
			rc = lnet_ni_eager_recv(ni, msg);
			lnet_net_lock(msg->msg_rx_cpt);
		}
	}

	if (rc == 0)
		rc = lnet_post_routed_recv_locked(msg, 0);
	return rc;
}

int
lnet_parse_local(struct lnet_ni *ni, struct lnet_msg *msg)
{
	int	rc;

	switch (msg->msg_type) {
	case LNET_MSG_ACK:
		rc = lnet_parse_ack(ni, msg);
		break;
	case LNET_MSG_PUT:
		rc = lnet_parse_put(ni, msg);
		break;
	case LNET_MSG_GET:
		rc = lnet_parse_get(ni, msg, msg->msg_rdma_get);
		break;
	case LNET_MSG_REPLY:
		rc = lnet_parse_reply(ni, msg);
		break;
	default: /* prevent an unused label if !kernel */
		LASSERT(0);
		return -EPROTO;
	}

	LASSERT(rc == 0 || rc == -ENOENT);
	return rc;
}

char *
lnet_msgtyp2str (int type)
{
	switch (type) {
	case LNET_MSG_ACK:
		return ("ACK");
	case LNET_MSG_PUT:
		return ("PUT");
	case LNET_MSG_GET:
		return ("GET");
	case LNET_MSG_REPLY:
		return ("REPLY");
	case LNET_MSG_HELLO:
		return ("HELLO");
	default:
		return ("<UNKNOWN>");
	}
}

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)
{
	int		rc = 0;
	int		cpt;
	int		for_me;
	struct lnet_msg	*msg;
	lnet_pid_t     dest_pid;
	lnet_nid_t     dest_nid;
	lnet_nid_t     src_nid;
	struct lnet_peer_ni *lpni;
	__u32          payload_length;
	__u32          type;

	LASSERT (!in_interrupt ());

	type = le32_to_cpu(hdr->type);
	src_nid = le64_to_cpu(hdr->src_nid);
	dest_nid = le64_to_cpu(hdr->dest_nid);
	dest_pid = le32_to_cpu(hdr->dest_pid);
	payload_length = le32_to_cpu(hdr->payload_length);

	for_me = (ni->ni_nid == dest_nid);
	cpt = lnet_cpt_of_nid(from_nid, ni);

	CDEBUG(D_NET, "TRACE: %s(%s) <- %s : %s - %s\n",
		libcfs_nid2str(dest_nid),
		libcfs_nid2str(ni->ni_nid),
		libcfs_nid2str(src_nid),
		lnet_msgtyp2str(type),
		(for_me) ? "for me" : "routed");

	switch (type) {
	case LNET_MSG_ACK:
	case LNET_MSG_GET:
		if (payload_length > 0) {
			CERROR("%s, src %s: bad %s payload %d (0 expected)\n",
			       libcfs_nid2str(from_nid),
			       libcfs_nid2str(src_nid),
			       lnet_msgtyp2str(type), payload_length);
			return -EPROTO;
		}
		break;

	case LNET_MSG_PUT:
	case LNET_MSG_REPLY:
		if (payload_length >
		    (__u32)(for_me ? LNET_MAX_PAYLOAD : LNET_MTU)) {
			CERROR("%s, src %s: bad %s payload %d "
			       "(%d max expected)\n",
			       libcfs_nid2str(from_nid),
			       libcfs_nid2str(src_nid),
			       lnet_msgtyp2str(type),
			       payload_length,
			       for_me ? LNET_MAX_PAYLOAD : LNET_MTU);
			return -EPROTO;
		}
		break;

	default:
		CERROR("%s, src %s: Bad message type 0x%x\n",
		       libcfs_nid2str(from_nid),
		       libcfs_nid2str(src_nid), type);
		return -EPROTO;
	}

	if (the_lnet.ln_routing &&
	    ni->ni_last_alive != ktime_get_real_seconds()) {
		/* NB: so far here is the only place to set NI status to "up */
		lnet_ni_lock(ni);
		ni->ni_last_alive = ktime_get_real_seconds();
		if (ni->ni_status != NULL &&
		    ni->ni_status->ns_status == LNET_NI_STATUS_DOWN)
			ni->ni_status->ns_status = LNET_NI_STATUS_UP;
		lnet_ni_unlock(ni);
	}

	/* Regard a bad destination NID as a protocol error.  Senders should
	 * know what they're doing; if they don't they're misconfigured, buggy
	 * or malicious so we chop them off at the knees :) */

	if (!for_me) {
		if (LNET_NIDNET(dest_nid) == LNET_NIDNET(ni->ni_nid)) {
			/* should have gone direct */
			CERROR("%s, src %s: Bad dest nid %s "
			       "(should have been sent direct)\n",
				libcfs_nid2str(from_nid),
				libcfs_nid2str(src_nid),
				libcfs_nid2str(dest_nid));
			return -EPROTO;
		}

		if (lnet_islocalnid(dest_nid)) {
			/* dest is another local NI; sender should have used
			 * this node's NID on its own network */
			CERROR("%s, src %s: Bad dest nid %s "
			       "(it's my nid but on a different network)\n",
				libcfs_nid2str(from_nid),
				libcfs_nid2str(src_nid),
				libcfs_nid2str(dest_nid));
			return -EPROTO;
		}

		if (rdma_req && type == LNET_MSG_GET) {
			CERROR("%s, src %s: Bad optimized GET for %s "
			       "(final destination must be me)\n",
				libcfs_nid2str(from_nid),
				libcfs_nid2str(src_nid),
				libcfs_nid2str(dest_nid));
			return -EPROTO;
		}

		if (!the_lnet.ln_routing) {
			CERROR("%s, src %s: Dropping message for %s "
			       "(routing not enabled)\n",
				libcfs_nid2str(from_nid),
				libcfs_nid2str(src_nid),
				libcfs_nid2str(dest_nid));
			goto drop;
		}
	}

	/* Message looks OK; we're not going to return an error, so we MUST
	 * call back lnd_recv() come what may... */

	if (!list_empty(&the_lnet.ln_test_peers) &&	/* normally we don't */
	    fail_peer(src_nid, 0)) {			/* shall we now? */
		CERROR("%s, src %s: Dropping %s to simulate failure\n",
		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
		       lnet_msgtyp2str(type));
		goto drop;
	}

	if (!list_empty(&the_lnet.ln_drop_rules) &&
	    lnet_drop_rule_match(hdr)) {
		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;
	}


	msg = lnet_msg_alloc();
	if (msg == NULL) {
		CERROR("%s, src %s: Dropping %s (out of memory)\n",
		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
		       lnet_msgtyp2str(type));
		goto drop;
	}

	/* msg zeroed in lnet_msg_alloc; i.e. flags all clear,
	 * pointers NULL etc */

	msg->msg_type = type;
	msg->msg_private = private;
	msg->msg_receiving = 1;
	msg->msg_rdma_get = rdma_req;
	msg->msg_len = msg->msg_wanted = payload_length;
	msg->msg_offset = 0;
	msg->msg_hdr = *hdr;
	/* for building message event */
	msg->msg_from = from_nid;
	if (!for_me) {
		msg->msg_target.pid	= dest_pid;
		msg->msg_target.nid	= dest_nid;
		msg->msg_routing	= 1;

	} else {
		/* convert common msg->hdr fields to host byteorder */
		msg->msg_hdr.type	= type;
		msg->msg_hdr.src_nid	= src_nid;
		msg->msg_hdr.src_pid	= le32_to_cpu(msg->msg_hdr.src_pid);
		msg->msg_hdr.dest_nid	= dest_nid;
		msg->msg_hdr.dest_pid	= dest_pid;
		msg->msg_hdr.payload_length = payload_length;
	}

	lnet_net_lock(cpt);
	lpni = lnet_nid2peerni_locked(from_nid, ni->ni_nid, cpt);
	if (IS_ERR(lpni)) {
		lnet_net_unlock(cpt);
		CERROR("%s, src %s: Dropping %s "
		       "(error %ld looking up sender)\n",
		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
		       lnet_msgtyp2str(type), PTR_ERR(lpni));
		lnet_msg_free(msg);
		if (rc == -ESHUTDOWN)
			/* We are shutting down.  Don't do anything more */
			return 0;
		goto drop;
	}
	msg->msg_rxpeer = lpni;
	msg->msg_rxni = ni;
	lnet_ni_addref_locked(ni, cpt);
	/* Multi-Rail: Primary NID of source. */
	msg->msg_initiator = lnet_peer_primary_nid_locked(src_nid);

	if (lnet_isrouter(msg->msg_rxpeer)) {
		lnet_peer_set_alive(msg->msg_rxpeer);
		if (avoid_asym_router_failure &&
		    LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
			/* received a remote message from router, update
			 * remote NI status on this router.
			 * NB: multi-hop routed message will be ignored.
			 */
			lnet_router_ni_update_locked(msg->msg_rxpeer,
						     LNET_NIDNET(src_nid));
		}
	}

	lnet_msg_commit(msg, cpt);

	/* message delay simulation */
	if (unlikely(!list_empty(&the_lnet.ln_delay_rules) &&
		     lnet_delay_rule_match_locked(hdr, msg))) {
		lnet_net_unlock(cpt);
		return 0;
	}

	if (!for_me) {
		rc = lnet_parse_forward_locked(ni, msg);
		lnet_net_unlock(cpt);

		if (rc < 0)
			goto free_drop;

		if (rc == LNET_CREDIT_OK) {
			lnet_ni_recv(ni, msg->msg_private, msg, 0,
				     0, payload_length, payload_length);
		}
		return 0;
	}

	lnet_net_unlock(cpt);

	rc = lnet_parse_local(ni, msg);
	if (rc != 0)
		goto free_drop;
	return 0;

 free_drop:
	LASSERT(msg->msg_md == NULL);
	lnet_finalize(msg, rc);

 drop:
	lnet_drop_message(ni, cpt, private, payload_length, type);
	return 0;
}
EXPORT_SYMBOL(lnet_parse);

void
lnet_drop_delayed_msg_list(struct list_head *head, char *reason)
{
	while (!list_empty(head)) {
		struct lnet_process_id id = {0};
		struct lnet_msg	*msg;

		msg = list_entry(head->next, struct lnet_msg, msg_list);
		list_del(&msg->msg_list);

		id.nid = msg->msg_hdr.src_nid;
		id.pid = msg->msg_hdr.src_pid;

		LASSERT(msg->msg_md == NULL);
		LASSERT(msg->msg_rx_delayed);
		LASSERT(msg->msg_rxpeer != NULL);
		LASSERT(msg->msg_hdr.type == LNET_MSG_PUT);

		CWARN("Dropping delayed PUT from %s portal %d match %llu"
		      " offset %d length %d: %s\n",
		      libcfs_id2str(id),
		      msg->msg_hdr.msg.put.ptl_index,
		      msg->msg_hdr.msg.put.match_bits,
		      msg->msg_hdr.msg.put.offset,
		      msg->msg_hdr.payload_length, reason);

		/* NB I can't drop msg's ref on msg_rxpeer until after I've
		 * called lnet_drop_message(), so I just hang onto msg as well
		 * until that's done */

		lnet_drop_message(msg->msg_rxni, msg->msg_rx_cpt,
				  msg->msg_private, msg->msg_len,
				  msg->msg_type);
		/*
		 * NB: message will not generate event because w/o attached MD,
		 * but we still should give error code so lnet_msg_decommit()
		 * can skip counters operations and other checks.
		 */
		lnet_finalize(msg, -ENOENT);
	}
}

void
lnet_recv_delayed_msg_list(struct list_head *head)
{
	while (!list_empty(head)) {
		struct lnet_msg	*msg;
		struct lnet_process_id id;

		msg = list_entry(head->next, struct lnet_msg, msg_list);
		list_del(&msg->msg_list);

		/* md won't disappear under me, since each msg
		 * holds a ref on it */

		id.nid = msg->msg_hdr.src_nid;
		id.pid = msg->msg_hdr.src_pid;

		LASSERT(msg->msg_rx_delayed);
		LASSERT(msg->msg_md != NULL);
		LASSERT(msg->msg_rxpeer != NULL);
		LASSERT(msg->msg_rxni != NULL);
		LASSERT(msg->msg_hdr.type == LNET_MSG_PUT);

		CDEBUG(D_NET, "Resuming delayed PUT from %s portal %d "
		       "match %llu offset %d length %d.\n",
			libcfs_id2str(id), msg->msg_hdr.msg.put.ptl_index,
			msg->msg_hdr.msg.put.match_bits,
			msg->msg_hdr.msg.put.offset,
			msg->msg_hdr.payload_length);

		lnet_recv_put(msg->msg_rxni, msg);
	}
}

/**
 * Initiate an asynchronous PUT operation.
 *
 * There are several events associated with a PUT: completion of the send on
 * the initiator node (LNET_EVENT_SEND), and when the send completes
 * successfully, the receipt of an acknowledgment (LNET_EVENT_ACK) indicating
 * that the operation was accepted by the target. The event LNET_EVENT_PUT is
 * used at the target node to indicate the completion of incoming data
 * delivery.
 *
 * The local events will be logged in the EQ associated with the MD pointed to
 * by \a mdh handle. Using a MD without an associated EQ results in these
 * events being discarded. In this case, the caller must have another
 * mechanism (e.g., a higher level protocol) for determining when it is safe
 * to modify the memory region associated with the MD.
 *
 * Note that LNet does not guarantee the order of LNET_EVENT_SEND and
 * LNET_EVENT_ACK, though intuitively ACK should happen after SEND.
 *
 * \param self Indicates the NID of a local interface through which to send
 * the PUT request. Use LNET_NID_ANY to let LNet choose one by itself.
 * \param mdh A handle for the MD that describes the memory to be sent. The MD
 * must be "free floating" (See LNetMDBind()).
 * \param ack Controls whether an acknowledgment is requested.
 * Acknowledgments are only sent when they are requested by the initiating
 * process and the target MD enables them.
 * \param target A process identifier for the target process.
 * \param portal The index in the \a target's portal table.
 * \param match_bits The match bits to use for MD selection at the target
 * process.
 * \param offset The offset into the target MD (only used when the target
 * MD has the LNET_MD_MANAGE_REMOTE option set).
 * \param hdr_data 64 bits of user data that can be included in the message
 * header. This data is written to an event queue entry at the target if an
 * EQ is present on the matching MD.
 *
 * \retval  0	   Success, and only in this case events will be generated
 * and logged to EQ (if it exists).
 * \retval -EIO    Simulated failure.
 * \retval -ENOMEM Memory allocation failure.
 * \retval -ENOENT Invalid MD object.
 *
 * \see struct lnet_event::hdr_data and lnet_event_kind_t.
 */
int
LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
	struct lnet_process_id target, unsigned int portal,
	__u64 match_bits, unsigned int offset,
	__u64 hdr_data)
{
	struct lnet_msg		*msg;
	struct lnet_libmd	*md;
	int			cpt;
	int			rc;

	LASSERT(the_lnet.ln_refcount > 0);

	if (!list_empty(&the_lnet.ln_test_peers) &&	/* normally we don't */
	    fail_peer(target.nid, 1)) {			/* shall we now? */
		CERROR("Dropping PUT to %s: simulated failure\n",
		       libcfs_id2str(target));
		return -EIO;
	}

	msg = lnet_msg_alloc();
	if (msg == NULL) {
		CERROR("Dropping PUT to %s: ENOMEM on struct lnet_msg\n",
		       libcfs_id2str(target));
		return -ENOMEM;
	}
	msg->msg_vmflush = !!memory_pressure_get();

	cpt = lnet_cpt_of_cookie(mdh.cookie);
	lnet_res_lock(cpt);

	md = lnet_handle2md(&mdh);
	if (md == NULL || md->md_threshold == 0 || md->md_me != NULL) {
		CERROR("Dropping PUT (%llu:%d:%s): MD (%d) invalid\n",
		       match_bits, portal, libcfs_id2str(target),
		       md == NULL ? -1 : md->md_threshold);
		if (md != NULL && md->md_me != NULL)
			CERROR("Source MD also attached to portal %d\n",
			       md->md_me->me_portal);
		lnet_res_unlock(cpt);

		lnet_msg_free(msg);
		return -ENOENT;
	}

	CDEBUG(D_NET, "LNetPut -> %s\n", libcfs_id2str(target));

	lnet_msg_attach_md(msg, md, 0, 0);

	lnet_prep_send(msg, LNET_MSG_PUT, target, 0, md->md_length);

	msg->msg_hdr.msg.put.match_bits = cpu_to_le64(match_bits);
	msg->msg_hdr.msg.put.ptl_index = cpu_to_le32(portal);
	msg->msg_hdr.msg.put.offset = cpu_to_le32(offset);
	msg->msg_hdr.msg.put.hdr_data = hdr_data;

	/* NB handles only looked up by creator (no flips) */
	if (ack == LNET_ACK_REQ) {
		msg->msg_hdr.msg.put.ack_wmd.wh_interface_cookie =
			the_lnet.ln_interface_cookie;
		msg->msg_hdr.msg.put.ack_wmd.wh_object_cookie =
			md->md_lh.lh_cookie;
	} else {
		msg->msg_hdr.msg.put.ack_wmd.wh_interface_cookie =
			LNET_WIRE_HANDLE_COOKIE_NONE;
		msg->msg_hdr.msg.put.ack_wmd.wh_object_cookie =
			LNET_WIRE_HANDLE_COOKIE_NONE;
	}

	lnet_res_unlock(cpt);

	lnet_build_msg_event(msg, LNET_EVENT_SEND);

	rc = lnet_send(self, msg, LNET_NID_ANY);
	if (rc != 0) {
		CNETERR("Error sending PUT to %s: %d\n",
			libcfs_id2str(target), rc);
		lnet_finalize(msg, rc);
	}

	/* completion will be signalled by an event */
	return 0;
}
EXPORT_SYMBOL(LNetPut);

/*
 * The LND can DMA direct to the GET md (i.e. no REPLY msg).  This
 * returns a msg for the LND to pass to lnet_finalize() when the sink
 * data has been received.
 *
 * CAVEAT EMPTOR: 'getmsg' is the original GET, which is freed when
 * lnet_finalize() is called on it, so the LND must call this first
 */
struct lnet_msg *
lnet_create_reply_msg(struct lnet_ni *ni, struct lnet_msg *getmsg)
{
	struct lnet_msg	*msg = lnet_msg_alloc();
	struct lnet_libmd *getmd = getmsg->msg_md;
	struct lnet_process_id peer_id = getmsg->msg_target;
	int cpt;

	LASSERT(!getmsg->msg_target_is_router);
	LASSERT(!getmsg->msg_routing);

	if (msg == NULL) {
		CERROR("%s: Dropping REPLY from %s: can't allocate msg\n",
		       libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id));
		goto drop;
	}

	cpt = lnet_cpt_of_cookie(getmd->md_lh.lh_cookie);
	lnet_res_lock(cpt);

	LASSERT(getmd->md_refcount > 0);

	if (getmd->md_threshold == 0) {
		CERROR("%s: Dropping REPLY from %s for inactive MD %p\n",
			libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id),
			getmd);
		lnet_res_unlock(cpt);
		goto drop;
	}

	LASSERT(getmd->md_offset == 0);

	CDEBUG(D_NET, "%s: Reply from %s md %p\n",
	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id), getmd);

	/* setup information for lnet_build_msg_event */
	msg->msg_initiator = getmsg->msg_txpeer->lpni_peer_net->lpn_peer->lp_primary_nid;
	msg->msg_from = peer_id.nid;
	msg->msg_type = LNET_MSG_GET; /* flag this msg as an "optimized" GET */
	msg->msg_hdr.src_nid = peer_id.nid;
	msg->msg_hdr.payload_length = getmd->md_length;
	msg->msg_receiving = 1; /* required by lnet_msg_attach_md */

	lnet_msg_attach_md(msg, getmd, getmd->md_offset, getmd->md_length);
	lnet_res_unlock(cpt);

	cpt = lnet_cpt_of_nid(peer_id.nid, ni);

	lnet_net_lock(cpt);
	lnet_msg_commit(msg, cpt);
	lnet_net_unlock(cpt);

	lnet_build_msg_event(msg, LNET_EVENT_REPLY);

	return msg;

 drop:
	cpt = lnet_cpt_of_nid(peer_id.nid, ni);

	lnet_net_lock(cpt);
	lnet_incr_stats(&ni->ni_stats, LNET_MSG_GET, LNET_STATS_TYPE_DROP);
	the_lnet.ln_counters[cpt]->drop_count++;
	the_lnet.ln_counters[cpt]->drop_length += getmd->md_length;
	lnet_net_unlock(cpt);

	if (msg != NULL)
		lnet_msg_free(msg);

	return NULL;
}
EXPORT_SYMBOL(lnet_create_reply_msg);

void
lnet_set_reply_msg_len(struct lnet_ni *ni, struct lnet_msg *reply,
		       unsigned int len)
{
	/* Set the REPLY length, now the RDMA that elides the REPLY message has
	 * completed and I know it. */
	LASSERT(reply != NULL);
	LASSERT(reply->msg_type == LNET_MSG_GET);
	LASSERT(reply->msg_ev.type == LNET_EVENT_REPLY);

	/* NB I trusted my peer to RDMA.  If she tells me she's written beyond
	 * the end of my buffer, I might as well be dead. */
	LASSERT(len <= reply->msg_ev.mlength);

	reply->msg_ev.mlength = len;
}
EXPORT_SYMBOL(lnet_set_reply_msg_len);

/**
 * Initiate an asynchronous GET operation.
 *
 * On the initiator node, an LNET_EVENT_SEND is logged when the GET request
 * is sent, and an LNET_EVENT_REPLY is logged when the data returned from
 * the target node in the REPLY has been written to local MD.
 *
 * On the target node, an LNET_EVENT_GET is logged when the GET request
 * arrives and is accepted into a MD.
 *
 * \param self,target,portal,match_bits,offset See the discussion in LNetPut().
 * \param mdh A handle for the MD that describes the memory into which the
 * requested data will be received. The MD must be "free floating" (See LNetMDBind()).
 *
 * \retval  0	   Success, and only in this case events will be generated
 * and logged to EQ (if it exists) of the MD.
 * \retval -EIO    Simulated failure.
 * \retval -ENOMEM Memory allocation failure.
 * \retval -ENOENT Invalid MD object.
 */
int
LNetGet(lnet_nid_t self, struct lnet_handle_md mdh,
	struct lnet_process_id target, unsigned int portal,
	__u64 match_bits, unsigned int offset)
{
	struct lnet_msg		*msg;
	struct lnet_libmd	*md;
	int			cpt;
	int			rc;

	LASSERT(the_lnet.ln_refcount > 0);

	if (!list_empty(&the_lnet.ln_test_peers) &&	/* normally we don't */
	    fail_peer(target.nid, 1))			/* shall we now? */
	{
		CERROR("Dropping GET to %s: simulated failure\n",
		       libcfs_id2str(target));
		return -EIO;
	}

	msg = lnet_msg_alloc();
	if (msg == NULL) {
		CERROR("Dropping GET to %s: ENOMEM on struct lnet_msg\n",
		       libcfs_id2str(target));
		return -ENOMEM;
	}

	cpt = lnet_cpt_of_cookie(mdh.cookie);
	lnet_res_lock(cpt);

	md = lnet_handle2md(&mdh);
	if (md == NULL || md->md_threshold == 0 || md->md_me != NULL) {
		CERROR("Dropping GET (%llu:%d:%s): MD (%d) invalid\n",
		       match_bits, portal, libcfs_id2str(target),
		       md == NULL ? -1 : md->md_threshold);
		if (md != NULL && md->md_me != NULL)
			CERROR("REPLY MD also attached to portal %d\n",
			       md->md_me->me_portal);

		lnet_res_unlock(cpt);

		lnet_msg_free(msg);
		return -ENOENT;
	}

	CDEBUG(D_NET, "LNetGet -> %s\n", libcfs_id2str(target));

	lnet_msg_attach_md(msg, md, 0, 0);

	lnet_prep_send(msg, LNET_MSG_GET, target, 0, 0);

	msg->msg_hdr.msg.get.match_bits = cpu_to_le64(match_bits);
	msg->msg_hdr.msg.get.ptl_index = cpu_to_le32(portal);
	msg->msg_hdr.msg.get.src_offset = cpu_to_le32(offset);
	msg->msg_hdr.msg.get.sink_length = cpu_to_le32(md->md_length);

	/* NB handles only looked up by creator (no flips) */
	msg->msg_hdr.msg.get.return_wmd.wh_interface_cookie =
		the_lnet.ln_interface_cookie;
	msg->msg_hdr.msg.get.return_wmd.wh_object_cookie =
		md->md_lh.lh_cookie;

	lnet_res_unlock(cpt);

	lnet_build_msg_event(msg, LNET_EVENT_SEND);

	rc = lnet_send(self, msg, LNET_NID_ANY);
	if (rc < 0) {
		CNETERR("Error sending GET to %s: %d\n",
			libcfs_id2str(target), rc);
		lnet_finalize(msg, rc);
	}

	/* completion will be signalled by an event */
	return 0;
}
EXPORT_SYMBOL(LNetGet);

/**
 * Calculate distance to node at \a dstnid.
 *
 * \param dstnid Target NID.
 * \param srcnidp If not NULL, NID of the local interface to reach \a dstnid
 * is saved here.
 * \param orderp If not NULL, order of the route to reach \a dstnid is saved
 * here.
 *
 * \retval 0 If \a dstnid belongs to a local interface, and reserved option
 * local_nid_dist_zero is set, which is the default.
 * \retval positives Distance to target NID, i.e. number of hops plus one.
 * \retval -EHOSTUNREACH If \a dstnid is not reachable.
 */
int
LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
{
	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;

	/* 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
	 * keep order 0 free for 0@lo and order 1 free for a local NID
	 * match */

	LASSERT(the_lnet.ln_refcount > 0);

	cpt = lnet_net_lock_current();

	while ((ni = lnet_get_next_ni_locked(NULL, ni))) {
		if (ni->ni_nid == dstnid) {
			if (srcnidp != NULL)
				*srcnidp = dstnid;
			if (orderp != NULL) {
				if (LNET_NETTYP(LNET_NIDNET(dstnid)) == LOLND)
					*orderp = 0;
				else
					*orderp = 1;
			}
			lnet_net_unlock(cpt);

			return local_nid_dist_zero ? 0 : 1;
		}

		if (LNET_NIDNET(ni->ni_nid) == dstnet) {
			/* Check if ni was originally created in
			 * current net namespace.
			 * If not, assign order above 0xffff0000,
			 * to make this ni not a priority. */
			if (!net_eq(ni->ni_net_ns, current->nsproxy->net_ns))
				order += 0xffff0000;

			if (srcnidp != NULL)
				*srcnidp = ni->ni_nid;
			if (orderp != NULL)
				*orderp = order;
			lnet_net_unlock(cpt);
			return 1;
		}

		order++;
	}

	rn_list = lnet_net2rnethash(dstnet);
	list_for_each(e, rn_list) {
		rnet = list_entry(e, struct lnet_remotenet, lrn_list);

		if (rnet->lrn_net == dstnet) {
			struct lnet_route *route;
			struct lnet_route *shortest = NULL;
			__u32 shortest_hops = LNET_UNDEFINED_HOPS;
			__u32 route_hops;

			LASSERT(!list_empty(&rnet->lrn_routes));

			list_for_each_entry(route, &rnet->lrn_routes,
					    lr_list) {
				route_hops = route->lr_hops;
				if (route_hops == LNET_UNDEFINED_HOPS)
					route_hops = 1;
				if (shortest == NULL ||
				    route_hops < shortest_hops) {
					shortest = route;
					shortest_hops = route_hops;
				}
			}

			LASSERT(shortest != NULL);
			hops = shortest_hops;
			if (srcnidp != NULL) {
				ni = lnet_get_next_ni_locked(
					shortest->lr_gateway->lpni_net,
					NULL);
				*srcnidp = ni->ni_nid;
			}
			if (orderp != NULL)
				*orderp = order;
			lnet_net_unlock(cpt);
			return hops + 1;
		}
		order++;
	}

	lnet_net_unlock(cpt);
	return -EHOSTUNREACH;
}
EXPORT_SYMBOL(LNetDist);