/*
 * 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, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/lnet/lib-msg.c
 *
 * Message decoding, parsing and finalizing routines
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <linux/lnet/lib-lnet.h>

void
lnet_build_unlink_event(struct lnet_libmd *md, struct lnet_event *ev)
{
	memset(ev, 0, sizeof(*ev));

	ev->status   = 0;
	ev->unlinked = 1;
	ev->type     = LNET_EVENT_UNLINK;
	lnet_md_deconstruct(md, &ev->md);
	lnet_md2handle(&ev->md_handle, md);
}

/*
 * Don't need any lock, must be called after lnet_commit_md
 */
void
lnet_build_msg_event(struct lnet_msg *msg, enum lnet_event_kind ev_type)
{
	struct lnet_hdr *hdr = &msg->msg_hdr;
	struct lnet_event *ev  = &msg->msg_ev;

	LASSERT(!msg->msg_routing);

	ev->type = ev_type;

	if (ev_type == LNET_EVENT_SEND) {
		/* event for active message */
		ev->target.nid    = le64_to_cpu(hdr->dest_nid);
		ev->target.pid    = le32_to_cpu(hdr->dest_pid);
		ev->initiator.nid = LNET_NID_ANY;
		ev->initiator.pid = the_lnet.ln_pid;
		ev->sender        = LNET_NID_ANY;
	} else {
		/* event for passive message */
		ev->target.pid    = hdr->dest_pid;
		ev->target.nid    = hdr->dest_nid;
		ev->initiator.pid = hdr->src_pid;
		ev->initiator.nid = hdr->src_nid;
		ev->rlength       = hdr->payload_length;
		ev->sender        = msg->msg_from;
		ev->mlength       = msg->msg_wanted;
		ev->offset        = msg->msg_offset;
	}

	switch (ev_type) {
	default:
		LBUG();

	case LNET_EVENT_PUT: /* passive PUT */
		ev->pt_index   = hdr->msg.put.ptl_index;
		ev->match_bits = hdr->msg.put.match_bits;
		ev->hdr_data   = hdr->msg.put.hdr_data;
		return;

	case LNET_EVENT_GET: /* passive GET */
		ev->pt_index   = hdr->msg.get.ptl_index;
		ev->match_bits = hdr->msg.get.match_bits;
		ev->hdr_data   = 0;
		return;

	case LNET_EVENT_ACK: /* ACK */
		ev->match_bits = hdr->msg.ack.match_bits;
		ev->mlength    = hdr->msg.ack.mlength;
		return;

	case LNET_EVENT_REPLY: /* REPLY */
		return;

	case LNET_EVENT_SEND: /* active message */
		if (msg->msg_type == LNET_MSG_PUT) {
			ev->pt_index   = le32_to_cpu(hdr->msg.put.ptl_index);
			ev->match_bits = le64_to_cpu(hdr->msg.put.match_bits);
			ev->offset     = le32_to_cpu(hdr->msg.put.offset);
			ev->mlength    =
			ev->rlength    = le32_to_cpu(hdr->payload_length);
			ev->hdr_data   = le64_to_cpu(hdr->msg.put.hdr_data);

		} else {
			LASSERT(msg->msg_type == LNET_MSG_GET);
			ev->pt_index   = le32_to_cpu(hdr->msg.get.ptl_index);
			ev->match_bits = le64_to_cpu(hdr->msg.get.match_bits);
			ev->mlength    =
			ev->rlength    = le32_to_cpu(hdr->msg.get.sink_length);
			ev->offset     = le32_to_cpu(hdr->msg.get.src_offset);
			ev->hdr_data   = 0;
		}
		return;
	}
}

void
lnet_msg_commit(struct lnet_msg *msg, int cpt)
{
	struct lnet_msg_container *container = the_lnet.ln_msg_containers[cpt];
	struct lnet_counters *counters  = the_lnet.ln_counters[cpt];

	/* routed message can be committed for both receiving and sending */
	LASSERT(!msg->msg_tx_committed);

	if (msg->msg_sending) {
		LASSERT(!msg->msg_receiving);

		msg->msg_tx_cpt = cpt;
		msg->msg_tx_committed = 1;
		if (msg->msg_rx_committed) { /* routed message REPLY */
			LASSERT(msg->msg_onactivelist);
			return;
		}
	} else {
		LASSERT(!msg->msg_sending);
		msg->msg_rx_cpt = cpt;
		msg->msg_rx_committed = 1;
	}

	LASSERT(!msg->msg_onactivelist);
	msg->msg_onactivelist = 1;
	list_add(&msg->msg_activelist, &container->msc_active);

	counters->msgs_alloc++;
	if (counters->msgs_alloc > counters->msgs_max)
		counters->msgs_max = counters->msgs_alloc;
}

static void
lnet_msg_decommit_tx(struct lnet_msg *msg, int status)
{
	struct lnet_counters	*counters;
	struct lnet_event *ev = &msg->msg_ev;

	LASSERT(msg->msg_tx_committed);
	if (status)
		goto out;

	counters = the_lnet.ln_counters[msg->msg_tx_cpt];
	switch (ev->type) {
	default: /* routed message */
		LASSERT(msg->msg_routing);
		LASSERT(msg->msg_rx_committed);
		LASSERT(!ev->type);

		counters->route_length += msg->msg_len;
		counters->route_count++;
		goto out;

	case LNET_EVENT_PUT:
		/* should have been decommitted */
		LASSERT(!msg->msg_rx_committed);
		/* overwritten while sending ACK */
		LASSERT(msg->msg_type == LNET_MSG_ACK);
		msg->msg_type = LNET_MSG_PUT; /* fix type */
		break;

	case LNET_EVENT_SEND:
		LASSERT(!msg->msg_rx_committed);
		if (msg->msg_type == LNET_MSG_PUT)
			counters->send_length += msg->msg_len;
		break;

	case LNET_EVENT_GET:
		LASSERT(msg->msg_rx_committed);
		/*
		 * overwritten while sending reply, we should never be
		 * here for optimized GET
		 */
		LASSERT(msg->msg_type == LNET_MSG_REPLY);
		msg->msg_type = LNET_MSG_GET; /* fix type */
		break;
	}

	counters->send_count++;
 out:
	lnet_return_tx_credits_locked(msg);
	msg->msg_tx_committed = 0;
}

static void
lnet_msg_decommit_rx(struct lnet_msg *msg, int status)
{
	struct lnet_counters *counters;
	struct lnet_event *ev = &msg->msg_ev;

	LASSERT(!msg->msg_tx_committed); /* decommitted or never committed */
	LASSERT(msg->msg_rx_committed);

	if (status)
		goto out;

	counters = the_lnet.ln_counters[msg->msg_rx_cpt];
	switch (ev->type) {
	default:
		LASSERT(!ev->type);
		LASSERT(msg->msg_routing);
		goto out;

	case LNET_EVENT_ACK:
		LASSERT(msg->msg_type == LNET_MSG_ACK);
		break;

	case LNET_EVENT_GET:
		/*
		 * type is "REPLY" if it's an optimized GET on passive side,
		 * because optimized GET will never be committed for sending,
		 * so message type wouldn't be changed back to "GET" by
		 * lnet_msg_decommit_tx(), see details in lnet_parse_get()
		 */
		LASSERT(msg->msg_type == LNET_MSG_REPLY ||
			msg->msg_type == LNET_MSG_GET);
		counters->send_length += msg->msg_wanted;
		break;

	case LNET_EVENT_PUT:
		LASSERT(msg->msg_type == LNET_MSG_PUT);
		break;

	case LNET_EVENT_REPLY:
		/*
		 * type is "GET" if it's an optimized GET on active side,
		 * see details in lnet_create_reply_msg()
		 */
		LASSERT(msg->msg_type == LNET_MSG_GET ||
			msg->msg_type == LNET_MSG_REPLY);
		break;
	}

	counters->recv_count++;
	if (ev->type == LNET_EVENT_PUT || ev->type == LNET_EVENT_REPLY)
		counters->recv_length += msg->msg_wanted;

 out:
	lnet_return_rx_credits_locked(msg);
	msg->msg_rx_committed = 0;
}

void
lnet_msg_decommit(struct lnet_msg *msg, int cpt, int status)
{
	int cpt2 = cpt;

	LASSERT(msg->msg_tx_committed || msg->msg_rx_committed);
	LASSERT(msg->msg_onactivelist);

	if (msg->msg_tx_committed) { /* always decommit for sending first */
		LASSERT(cpt == msg->msg_tx_cpt);
		lnet_msg_decommit_tx(msg, status);
	}

	if (msg->msg_rx_committed) {
		/* forwarding msg committed for both receiving and sending */
		if (cpt != msg->msg_rx_cpt) {
			lnet_net_unlock(cpt);
			cpt2 = msg->msg_rx_cpt;
			lnet_net_lock(cpt2);
		}
		lnet_msg_decommit_rx(msg, status);
	}

	list_del(&msg->msg_activelist);
	msg->msg_onactivelist = 0;

	the_lnet.ln_counters[cpt2]->msgs_alloc--;

	if (cpt2 != cpt) {
		lnet_net_unlock(cpt2);
		lnet_net_lock(cpt);
	}
}

void
lnet_msg_attach_md(struct lnet_msg *msg, struct lnet_libmd *md,
		   unsigned int offset, unsigned int mlen)
{
	/* NB: @offset and @len are only useful for receiving */
	/*
	 * Here, we attach the MD on lnet_msg and mark it busy and
	 * decrementing its threshold. Come what may, the lnet_msg "owns"
	 * the MD until a call to lnet_msg_detach_md or lnet_finalize()
	 * signals completion.
	 */
	LASSERT(!msg->msg_routing);

	msg->msg_md = md;
	if (msg->msg_receiving) { /* committed for receiving */
		msg->msg_offset = offset;
		msg->msg_wanted = mlen;
	}

	md->md_refcount++;
	if (md->md_threshold != LNET_MD_THRESH_INF) {
		LASSERT(md->md_threshold > 0);
		md->md_threshold--;
	}

	/* build umd in event */
	lnet_md2handle(&msg->msg_ev.md_handle, md);
	lnet_md_deconstruct(md, &msg->msg_ev.md);
}

void
lnet_msg_detach_md(struct lnet_msg *msg, int status)
{
	struct lnet_libmd *md = msg->msg_md;
	int unlink;

	/* Now it's safe to drop my caller's ref */
	md->md_refcount--;
	LASSERT(md->md_refcount >= 0);

	unlink = lnet_md_unlinkable(md);
	if (md->md_eq) {
		msg->msg_ev.status   = status;
		msg->msg_ev.unlinked = unlink;
		lnet_eq_enqueue_event(md->md_eq, &msg->msg_ev);
	}

	if (unlink)
		lnet_md_unlink(md);

	msg->msg_md = NULL;
}

static int
lnet_complete_msg_locked(struct lnet_msg *msg, int cpt)
{
	struct lnet_handle_wire ack_wmd;
	int rc;
	int status = msg->msg_ev.status;

	LASSERT(msg->msg_onactivelist);

	if (!status && msg->msg_ack) {
		/* Only send an ACK if the PUT completed successfully */

		lnet_msg_decommit(msg, cpt, 0);

		msg->msg_ack = 0;
		lnet_net_unlock(cpt);

		LASSERT(msg->msg_ev.type == LNET_EVENT_PUT);
		LASSERT(!msg->msg_routing);

		ack_wmd = msg->msg_hdr.msg.put.ack_wmd;

		lnet_prep_send(msg, LNET_MSG_ACK, msg->msg_ev.initiator, 0, 0);

		msg->msg_hdr.msg.ack.dst_wmd = ack_wmd;
		msg->msg_hdr.msg.ack.match_bits = msg->msg_ev.match_bits;
		msg->msg_hdr.msg.ack.mlength = cpu_to_le32(msg->msg_ev.mlength);

		/*
		 * NB: we probably want to use NID of msg::msg_from as 3rd
		 * parameter (router NID) if it's routed message
		 */
		rc = lnet_send(msg->msg_ev.target.nid, msg, LNET_NID_ANY);

		lnet_net_lock(cpt);
		/*
		 * NB: message is committed for sending, we should return
		 * on success because LND will finalize this message later.
		 *
		 * Also, there is possibility that message is committed for
		 * sending and also failed before delivering to LND,
		 * i.e: ENOMEM, in that case we can't fall through either
		 * because CPT for sending can be different with CPT for
		 * receiving, so we should return back to lnet_finalize()
		 * to make sure we are locking the correct partition.
		 */
		return rc;

	} else if (!status &&	/* OK so far */
		   (msg->msg_routing && !msg->msg_sending)) {
		/* not forwarded */
		LASSERT(!msg->msg_receiving);	/* called back recv already */
		lnet_net_unlock(cpt);

		rc = lnet_send(LNET_NID_ANY, msg, LNET_NID_ANY);

		lnet_net_lock(cpt);
		/*
		 * NB: message is committed for sending, we should return
		 * on success because LND will finalize this message later.
		 *
		 * Also, there is possibility that message is committed for
		 * sending and also failed before delivering to LND,
		 * i.e: ENOMEM, in that case we can't fall through either:
		 * - The rule is message must decommit for sending first if
		 *   the it's committed for both sending and receiving
		 * - CPT for sending can be different with CPT for receiving,
		 *   so we should return back to lnet_finalize() to make
		 *   sure we are locking the correct partition.
		 */
		return rc;
	}

	lnet_msg_decommit(msg, cpt, status);
	lnet_msg_free(msg);
	return 0;
}

void
lnet_finalize(struct lnet_ni *ni, struct lnet_msg *msg, int status)
{
	struct lnet_msg_container *container;
	int my_slot;
	int cpt;
	int rc;
	int i;

	LASSERT(!in_interrupt());

	if (!msg)
		return;

	msg->msg_ev.status = status;

	if (msg->msg_md) {
		cpt = lnet_cpt_of_cookie(msg->msg_md->md_lh.lh_cookie);

		lnet_res_lock(cpt);
		lnet_msg_detach_md(msg, status);
		lnet_res_unlock(cpt);
	}

 again:
	rc = 0;
	if (!msg->msg_tx_committed && !msg->msg_rx_committed) {
		/* not committed to network yet */
		LASSERT(!msg->msg_onactivelist);
		lnet_msg_free(msg);
		return;
	}

	/*
	 * NB: routed message can be committed for both receiving and sending,
	 * we should finalize in LIFO order and keep counters correct.
	 * (finalize sending first then finalize receiving)
	 */
	cpt = msg->msg_tx_committed ? msg->msg_tx_cpt : msg->msg_rx_cpt;
	lnet_net_lock(cpt);

	container = the_lnet.ln_msg_containers[cpt];
	list_add_tail(&msg->msg_list, &container->msc_finalizing);

	/*
	 * Recursion breaker.  Don't complete the message here if I am (or
	 * enough other threads are) already completing messages
	 */
	my_slot = -1;
	for (i = 0; i < container->msc_nfinalizers; i++) {
		if (container->msc_finalizers[i] == current)
			break;

		if (my_slot < 0 && !container->msc_finalizers[i])
			my_slot = i;
	}

	if (i < container->msc_nfinalizers || my_slot < 0) {
		lnet_net_unlock(cpt);
		return;
	}

	container->msc_finalizers[my_slot] = current;

	while (!list_empty(&container->msc_finalizing)) {
		msg = list_entry(container->msc_finalizing.next,
				 struct lnet_msg, msg_list);

		list_del(&msg->msg_list);

		/*
		 * NB drops and regains the lnet lock if it actually does
		 * anything, so my finalizing friends can chomp along too
		 */
		rc = lnet_complete_msg_locked(msg, cpt);
		if (rc)
			break;
	}

	if (unlikely(!list_empty(&the_lnet.ln_delay_rules))) {
		lnet_net_unlock(cpt);
		lnet_delay_rule_check();
		lnet_net_lock(cpt);
	}

	container->msc_finalizers[my_slot] = NULL;
	lnet_net_unlock(cpt);

	if (rc)
		goto again;
}
EXPORT_SYMBOL(lnet_finalize);

void
lnet_msg_container_cleanup(struct lnet_msg_container *container)
{
	int count = 0;

	if (!container->msc_init)
		return;

	while (!list_empty(&container->msc_active)) {
		struct lnet_msg *msg;

		msg = list_entry(container->msc_active.next,
				 struct lnet_msg, msg_activelist);
		LASSERT(msg->msg_onactivelist);
		msg->msg_onactivelist = 0;
		list_del(&msg->msg_activelist);
		lnet_msg_free(msg);
		count++;
	}

	if (count > 0)
		CERROR("%d active msg on exit\n", count);

	if (container->msc_finalizers) {
		LIBCFS_FREE(container->msc_finalizers,
			    container->msc_nfinalizers *
			    sizeof(*container->msc_finalizers));
		container->msc_finalizers = NULL;
	}
	container->msc_init = 0;
}

int
lnet_msg_container_setup(struct lnet_msg_container *container, int cpt)
{
	container->msc_init = 1;

	INIT_LIST_HEAD(&container->msc_active);
	INIT_LIST_HEAD(&container->msc_finalizing);

	/* number of CPUs */
	container->msc_nfinalizers = cfs_cpt_weight(lnet_cpt_table(), cpt);

	LIBCFS_CPT_ALLOC(container->msc_finalizers, lnet_cpt_table(), cpt,
			 container->msc_nfinalizers *
			 sizeof(*container->msc_finalizers));

	if (!container->msc_finalizers) {
		CERROR("Failed to allocate message finalizers\n");
		lnet_msg_container_cleanup(container);
		return -ENOMEM;
	}

	return 0;
}

void
lnet_msg_containers_destroy(void)
{
	struct lnet_msg_container *container;
	int i;

	if (!the_lnet.ln_msg_containers)
		return;

	cfs_percpt_for_each(container, i, the_lnet.ln_msg_containers)
		lnet_msg_container_cleanup(container);

	cfs_percpt_free(the_lnet.ln_msg_containers);
	the_lnet.ln_msg_containers = NULL;
}

int
lnet_msg_containers_create(void)
{
	struct lnet_msg_container *container;
	int rc;
	int i;

	the_lnet.ln_msg_containers = cfs_percpt_alloc(lnet_cpt_table(),
						      sizeof(*container));

	if (!the_lnet.ln_msg_containers) {
		CERROR("Failed to allocate cpu-partition data for network\n");
		return -ENOMEM;
	}

	cfs_percpt_for_each(container, i, the_lnet.ln_msg_containers) {
		rc = lnet_msg_container_setup(container, i);
		if (rc) {
			lnet_msg_containers_destroy();
			return rc;
		}
	}

	return 0;
}