/*
 * 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.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.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/lnet/peer.c
 */

#define DEBUG_SUBSYSTEM S_LNET

#include "../../include/linux/lnet/lib-lnet.h"

int
lnet_peer_tables_create(void)
{
	struct lnet_peer_table	*ptable;
	struct list_head		*hash;
	int			i;
	int			j;

	the_lnet.ln_peer_tables = cfs_percpt_alloc(lnet_cpt_table(),
						   sizeof(*ptable));
	if (the_lnet.ln_peer_tables == NULL) {
		CERROR("Failed to allocate cpu-partition peer tables\n");
		return -ENOMEM;
	}

	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
		INIT_LIST_HEAD(&ptable->pt_deathrow);

		LIBCFS_CPT_ALLOC(hash, lnet_cpt_table(), i,
				 LNET_PEER_HASH_SIZE * sizeof(*hash));
		if (hash == NULL) {
			CERROR("Failed to create peer hash table\n");
			lnet_peer_tables_destroy();
			return -ENOMEM;
		}

		for (j = 0; j < LNET_PEER_HASH_SIZE; j++)
			INIT_LIST_HEAD(&hash[j]);
		ptable->pt_hash = hash; /* sign of initialization */
	}

	return 0;
}

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 == NULL)
		return;

	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
		hash = ptable->pt_hash;
		if (hash == NULL) /* not initialized */
			break;

		LASSERT(list_empty(&ptable->pt_deathrow));

		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;
}

void
lnet_peer_tables_cleanup(void)
{
	struct lnet_peer_table	*ptable;
	int			i;
	int			j;

	LASSERT(the_lnet.ln_shutdown);	/* i.e. no new peers */

	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
		lnet_net_lock(i);

		for (j = 0; j < LNET_PEER_HASH_SIZE; j++) {
			struct list_head *peers = &ptable->pt_hash[j];

			while (!list_empty(peers)) {
				lnet_peer_t *lp = list_entry(peers->next,
								 lnet_peer_t,
								 lp_hashlist);
				list_del_init(&lp->lp_hashlist);
				/* lose hash table's ref */
				lnet_peer_decref_locked(lp);
			}
		}

		lnet_net_unlock(i);
	}

	cfs_percpt_for_each(ptable, i, the_lnet.ln_peer_tables) {
		LIST_HEAD(deathrow);
		lnet_peer_t	*lp;

		lnet_net_lock(i);

		for (j = 3; ptable->pt_number != 0; j++) {
			lnet_net_unlock(i);

			if ((j & (j - 1)) == 0) {
				CDEBUG(D_WARNING,
				       "Waiting for %d peers on peer table\n",
				       ptable->pt_number);
			}
			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_timeout(cfs_time_seconds(1) / 2);
			lnet_net_lock(i);
		}
		list_splice_init(&ptable->pt_deathrow, &deathrow);

		lnet_net_unlock(i);

		while (!list_empty(&deathrow)) {
			lp = list_entry(deathrow.next,
					    lnet_peer_t, lp_hashlist);
			list_del(&lp->lp_hashlist);
			LIBCFS_FREE(lp, sizeof(*lp));
		}
	}
}

void
lnet_destroy_peer_locked(lnet_peer_t *lp)
{
	struct lnet_peer_table *ptable;

	LASSERT(lp->lp_refcount == 0);
	LASSERT(lp->lp_rtr_refcount == 0);
	LASSERT(list_empty(&lp->lp_txq));
	LASSERT(list_empty(&lp->lp_hashlist));
	LASSERT(lp->lp_txqnob == 0);

	ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
	LASSERT(ptable->pt_number > 0);
	ptable->pt_number--;

	lnet_ni_decref_locked(lp->lp_ni, lp->lp_cpt);
	lp->lp_ni = NULL;

	list_add(&lp->lp_hashlist, &ptable->pt_deathrow);
}

lnet_peer_t *
lnet_find_peer_locked(struct lnet_peer_table *ptable, lnet_nid_t nid)
{
	struct list_head	*peers;
	lnet_peer_t	*lp;

	LASSERT(!the_lnet.ln_shutdown);

	peers = &ptable->pt_hash[lnet_nid2peerhash(nid)];
	list_for_each_entry(lp, peers, lp_hashlist) {
		if (lp->lp_nid == nid) {
			lnet_peer_addref_locked(lp);
			return lp;
		}
	}

	return NULL;
}

int
lnet_nid2peer_locked(lnet_peer_t **lpp, lnet_nid_t nid, int cpt)
{
	struct lnet_peer_table	*ptable;
	lnet_peer_t		*lp = NULL;
	lnet_peer_t		*lp2;
	int			cpt2;
	int			rc = 0;

	*lpp = NULL;
	if (the_lnet.ln_shutdown) /* it's shutting down */
		return -ESHUTDOWN;

	/* 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);

	ptable = the_lnet.ln_peer_tables[cpt2];
	lp = lnet_find_peer_locked(ptable, nid);
	if (lp != NULL) {
		*lpp = lp;
		return 0;
	}

	if (!list_empty(&ptable->pt_deathrow)) {
		lp = list_entry(ptable->pt_deathrow.next,
				    lnet_peer_t, lp_hashlist);
		list_del(&lp->lp_hashlist);
	}

	/*
	 * take extra refcount in case another thread has shutdown LNet
	 * and destroyed locks and peer-table before I finish the allocation
	 */
	ptable->pt_number++;
	lnet_net_unlock(cpt);

	if (lp != NULL)
		memset(lp, 0, sizeof(*lp));
	else
		LIBCFS_CPT_ALLOC(lp, lnet_cpt_table(), cpt2, sizeof(*lp));

	if (lp == NULL) {
		rc = -ENOMEM;
		lnet_net_lock(cpt);
		goto out;
	}

	INIT_LIST_HEAD(&lp->lp_txq);
	INIT_LIST_HEAD(&lp->lp_rtrq);
	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_feats = LNET_PING_FEAT_INVAL;
	lp->lp_nid = nid;
	lp->lp_cpt = cpt2;
	lp->lp_refcount = 2;	/* 1 for caller; 1 for hash */
	lp->lp_rtr_refcount = 0;

	lnet_net_lock(cpt);

	if (the_lnet.ln_shutdown) {
		rc = -ESHUTDOWN;
		goto out;
	}

	lp2 = lnet_find_peer_locked(ptable, nid);
	if (lp2 != NULL) {
		*lpp = lp2;
		goto out;
	}

	lp->lp_ni = lnet_net2ni_locked(LNET_NIDNET(nid), cpt2);
	if (lp->lp_ni == NULL) {
		rc = -EHOSTUNREACH;
		goto out;
	}

	lp->lp_txcredits    =
	lp->lp_mintxcredits = lp->lp_ni->ni_peertxcredits;
	lp->lp_rtrcredits    =
	lp->lp_minrtrcredits = lnet_peer_buffer_credits(lp->lp_ni);

	list_add_tail(&lp->lp_hashlist,
			  &ptable->pt_hash[lnet_nid2peerhash(nid)]);
	ptable->pt_version++;
	*lpp = lp;

	return 0;
out:
	if (lp != NULL)
		list_add(&lp->lp_hashlist, &ptable->pt_deathrow);
	ptable->pt_number--;
	return rc;
}

void
lnet_debug_peer(lnet_nid_t nid)
{
	char		*aliveness = "NA";
	lnet_peer_t	*lp;
	int		rc;
	int		cpt;

	cpt = lnet_cpt_of_nid(nid);
	lnet_net_lock(cpt);

	rc = lnet_nid2peer_locked(&lp, nid, cpt);
	if (rc != 0) {
		lnet_net_unlock(cpt);
		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";

	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);

	lnet_peer_decref_locked(lp);

	lnet_net_unlock(cpt);
}