drivers/staging/lustre/lustre/ptlrpc/pinger.c - arm/linux - Git at Google

 /*
  * 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) 2011, 2015, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * lustre/ptlrpc/pinger.c
  *
  * Portal-RPC reconnection and replay operations, for use in recovery.
  */

 #define DEBUG_SUBSYSTEM S_RPC

 #include <obd_support.h>
 #include <obd_class.h>
 #include "ptlrpc_internal.h"

 struct mutex pinger_mutex;
 static LIST_HEAD(pinger_imports);
 static struct list_head timeout_list = LIST_HEAD_INIT(timeout_list);

 struct ptlrpc_request *
 ptlrpc_prep_ping(struct obd_import *imp)
 {
 	struct ptlrpc_request *req;

 	req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING,
 					LUSTRE_OBD_VERSION, OBD_PING);
 	if (req) {
 		ptlrpc_request_set_replen(req);
 		req->rq_no_resend = 1;
 		req->rq_no_delay = 1;
 	}
 	return req;
 }

 int ptlrpc_obd_ping(struct obd_device *obd)
 {
 	int rc;
 	struct ptlrpc_request *req;

 	req = ptlrpc_prep_ping(obd->u.cli.cl_import);
 	if (!req)
 		return -ENOMEM;

 	req->rq_send_state = LUSTRE_IMP_FULL;

 	rc = ptlrpc_queue_wait(req);

 	ptlrpc_req_finished(req);

 	return rc;
 }
 EXPORT_SYMBOL(ptlrpc_obd_ping);

 static int ptlrpc_ping(struct obd_import *imp)
 {
 	struct ptlrpc_request *req;

 	req = ptlrpc_prep_ping(imp);
 	if (!req) {
 		CERROR("OOM trying to ping %s->%s\n",
 		       imp->imp_obd->obd_uuid.uuid,
 		       obd2cli_tgt(imp->imp_obd));
 		return -ENOMEM;
 	}

 	DEBUG_REQ(D_INFO, req, "pinging %s->%s",
 		  imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 	ptlrpcd_add_req(req);

 	return 0;
 }

 static void ptlrpc_update_next_ping(struct obd_import *imp, int soon)
 {
 	int time = soon ? PING_INTERVAL_SHORT : PING_INTERVAL;

 	if (imp->imp_state == LUSTRE_IMP_DISCON) {
 		int dtime = max_t(int, CONNECTION_SWITCH_MIN,
 				  AT_OFF ? 0 :
 				  at_get(&imp->imp_at.iat_net_latency));
 		time = min(time, dtime);
 	}
 	imp->imp_next_ping = cfs_time_shift(time);
 }

 static inline int imp_is_deactive(struct obd_import *imp)
 {
 	return (imp->imp_deactive ||
 		OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_IMP_DEACTIVE));
 }

 static inline int ptlrpc_next_reconnect(struct obd_import *imp)
 {
 	if (imp->imp_server_timeout)
 		return cfs_time_shift(obd_timeout / 2);
 	else
 		return cfs_time_shift(obd_timeout);
 }

 static long pinger_check_timeout(unsigned long time)
 {
 	struct timeout_item *item;
 	unsigned long timeout = PING_INTERVAL;

 	/* The timeout list is a increase order sorted list */
 	mutex_lock(&pinger_mutex);
 	list_for_each_entry(item, &timeout_list, ti_chain) {
 		int ti_timeout = item->ti_timeout;

 		if (timeout > ti_timeout)
 			timeout = ti_timeout;
 		break;
 	}
 	mutex_unlock(&pinger_mutex);

 	return cfs_time_sub(cfs_time_add(time, cfs_time_seconds(timeout)),
 					 cfs_time_current());
 }

 static bool ir_up;

 void ptlrpc_pinger_ir_up(void)
 {
 	CDEBUG(D_HA, "IR up\n");
 	ir_up = true;
 }
 EXPORT_SYMBOL(ptlrpc_pinger_ir_up);

 void ptlrpc_pinger_ir_down(void)
 {
 	CDEBUG(D_HA, "IR down\n");
 	ir_up = false;
 }
 EXPORT_SYMBOL(ptlrpc_pinger_ir_down);

 static void ptlrpc_pinger_process_import(struct obd_import *imp,
 					 unsigned long this_ping)
 {
 	int level;
 	int force;
 	int force_next;
 	int suppress;

 	spin_lock(&imp->imp_lock);

 	level = imp->imp_state;
 	force = imp->imp_force_verify;
 	force_next = imp->imp_force_next_verify;
 	/*
 	 * This will be used below only if the import is "FULL".
 	 */
 	suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);

 	imp->imp_force_verify = 0;

 	if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
 	    !force) {
 		spin_unlock(&imp->imp_lock);
 		return;
 	}

 	imp->imp_force_next_verify = 0;

 	spin_unlock(&imp->imp_lock);

 	CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u force %u force_next %u deactive %u pingable %u suppress %u\n",
 	       imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 	       ptlrpc_import_state_name(level), level, force, force_next,
 	       imp->imp_deactive, imp->imp_pingable, suppress);

 	if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
 		/* wait for a while before trying recovery again */
 		imp->imp_next_ping = ptlrpc_next_reconnect(imp);
 		if (!imp->imp_no_pinger_recover)
 			ptlrpc_initiate_recovery(imp);
 	} else if (level != LUSTRE_IMP_FULL ||
 		   imp->imp_obd->obd_no_recov ||
 		   imp_is_deactive(imp)) {
 		CDEBUG(D_HA, "%s->%s: not pinging (in recovery or recovery disabled: %s)\n",
 		       imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 		       ptlrpc_import_state_name(level));
 		if (force) {
 			spin_lock(&imp->imp_lock);
 			imp->imp_force_verify = 1;
 			spin_unlock(&imp->imp_lock);
 		}
 	} else if ((imp->imp_pingable && !suppress) || force_next || force) {
 		ptlrpc_ping(imp);
 	}
 }

 static int ptlrpc_pinger_main(void *arg)
 {
 	struct ptlrpc_thread *thread = arg;

 	/* Record that the thread is running */
 	thread_set_flags(thread, SVC_RUNNING);
 	wake_up(&thread->t_ctl_waitq);

 	/* And now, loop forever, pinging as needed. */
 	while (1) {
 		unsigned long this_ping = cfs_time_current();
 		struct l_wait_info lwi;
 		long time_to_next_wake;
 		struct timeout_item *item;
 		struct list_head *iter;

 		mutex_lock(&pinger_mutex);
 		list_for_each_entry(item, &timeout_list, ti_chain) {
 			item->ti_cb(item, item->ti_cb_data);
 		}
 		list_for_each(iter, &pinger_imports) {
 			struct obd_import *imp =
 				list_entry(iter, struct obd_import,
 					   imp_pinger_chain);

 			ptlrpc_pinger_process_import(imp, this_ping);
 			/* obd_timeout might have changed */
 			if (imp->imp_pingable && imp->imp_next_ping &&
 			    cfs_time_after(imp->imp_next_ping,
 					   cfs_time_add(this_ping,
 							cfs_time_seconds(PING_INTERVAL))))
 				ptlrpc_update_next_ping(imp, 0);
 		}
 		mutex_unlock(&pinger_mutex);

 		/* Wait until the next ping time, or until we're stopped. */
 		time_to_next_wake = pinger_check_timeout(this_ping);
 		/* The ping sent by ptlrpc_send_rpc may get sent out
 		 * say .01 second after this.
 		 * ptlrpc_pinger_sending_on_import will then set the
 		 * next ping time to next_ping + .01 sec, which means
 		 * we will SKIP the next ping at next_ping, and the
 		 * ping will get sent 2 timeouts from now!  Beware.
 		 */
 		CDEBUG(D_INFO, "next wakeup in " CFS_DURATION_T " (%ld)\n",
 		       time_to_next_wake,
 		       cfs_time_add(this_ping,
 				    cfs_time_seconds(PING_INTERVAL)));
 		if (time_to_next_wake > 0) {
 			lwi = LWI_TIMEOUT(max_t(long, time_to_next_wake,
 						cfs_time_seconds(1)),
 					  NULL, NULL);
 			l_wait_event(thread->t_ctl_waitq,
 				     thread_is_stopping(thread) ||
 				     thread_is_event(thread),
 				     &lwi);
 			if (thread_test_and_clear_flags(thread, SVC_STOPPING))
 				break;
 			/* woken after adding import to reset timer */
 			thread_test_and_clear_flags(thread, SVC_EVENT);
 		}
 	}

 	thread_set_flags(thread, SVC_STOPPED);
 	wake_up(&thread->t_ctl_waitq);

 	CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
 	return 0;
 }

 static struct ptlrpc_thread pinger_thread;

 int ptlrpc_start_pinger(void)
 {
 	struct l_wait_info lwi = { 0 };
 	struct task_struct *task;
 	int rc;

 	if (!thread_is_init(&pinger_thread) &&
 	    !thread_is_stopped(&pinger_thread))
 		return -EALREADY;

 	init_waitqueue_head(&pinger_thread.t_ctl_waitq);

 	strcpy(pinger_thread.t_name, "ll_ping");

 	task = kthread_run(ptlrpc_pinger_main, &pinger_thread,
 			   pinger_thread.t_name);
 	if (IS_ERR(task)) {
 		rc = PTR_ERR(task);
 		CERROR("cannot start pinger thread: rc = %d\n", rc);
 		return rc;
 	}
 	l_wait_event(pinger_thread.t_ctl_waitq,
 		     thread_is_running(&pinger_thread), &lwi);

 	return 0;
 }

 static int ptlrpc_pinger_remove_timeouts(void);

 int ptlrpc_stop_pinger(void)
 {
 	struct l_wait_info lwi = { 0 };
 	int rc = 0;

 	if (thread_is_init(&pinger_thread) ||
 	    thread_is_stopped(&pinger_thread))
 		return -EALREADY;

 	ptlrpc_pinger_remove_timeouts();
 	thread_set_flags(&pinger_thread, SVC_STOPPING);
 	wake_up(&pinger_thread.t_ctl_waitq);

 	l_wait_event(pinger_thread.t_ctl_waitq,
 		     thread_is_stopped(&pinger_thread), &lwi);

 	return rc;
 }

 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
 {
 	ptlrpc_update_next_ping(imp, 0);
 }

 void ptlrpc_pinger_commit_expected(struct obd_import *imp)
 {
 	ptlrpc_update_next_ping(imp, 1);
 	assert_spin_locked(&imp->imp_lock);
 	/*
 	 * Avoid reading stale imp_connect_data.  When not sure if pings are
 	 * expected or not on next connection, we assume they are not and force
 	 * one anyway to guarantee the chance of updating
 	 * imp_peer_committed_transno.
 	 */
 	if (imp->imp_state != LUSTRE_IMP_FULL ||
 	    OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
 		imp->imp_force_next_verify = 1;
 }

 int ptlrpc_pinger_add_import(struct obd_import *imp)
 {
 	if (!list_empty(&imp->imp_pinger_chain))
 		return -EALREADY;

 	mutex_lock(&pinger_mutex);
 	CDEBUG(D_HA, "adding pingable import %s->%s\n",
 	       imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 	/* if we add to pinger we want recovery on this import */
 	imp->imp_obd->obd_no_recov = 0;
 	ptlrpc_update_next_ping(imp, 0);
 	/* XXX sort, blah blah */
 	list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
 	class_import_get(imp);

 	ptlrpc_pinger_wake_up();
 	mutex_unlock(&pinger_mutex);

 	return 0;
 }
 EXPORT_SYMBOL(ptlrpc_pinger_add_import);

 int ptlrpc_pinger_del_import(struct obd_import *imp)
 {
 	if (list_empty(&imp->imp_pinger_chain))
 		return -ENOENT;

 	mutex_lock(&pinger_mutex);
 	list_del_init(&imp->imp_pinger_chain);
 	CDEBUG(D_HA, "removing pingable import %s->%s\n",
 	       imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 	/* if we remove from pinger we don't want recovery on this import */
 	imp->imp_obd->obd_no_recov = 1;
 	class_import_put(imp);
 	mutex_unlock(&pinger_mutex);
 	return 0;
 }
 EXPORT_SYMBOL(ptlrpc_pinger_del_import);

 /**
  * Register a timeout callback to the pinger list, and the callback will
  * be called when timeout happens.
  */
 static struct timeout_item *ptlrpc_new_timeout(int time,
 					       enum timeout_event event,
 					       timeout_cb_t cb, void *data)
 {
 	struct timeout_item *ti;

 	ti = kzalloc(sizeof(*ti), GFP_NOFS);
 	if (!ti)
 		return NULL;

 	INIT_LIST_HEAD(&ti->ti_obd_list);
 	INIT_LIST_HEAD(&ti->ti_chain);
 	ti->ti_timeout = time;
 	ti->ti_event = event;
 	ti->ti_cb = cb;
 	ti->ti_cb_data = data;

 	return ti;
 }

 /**
  * Register timeout event on the pinger thread.
  * Note: the timeout list is an sorted list with increased timeout value.
  */
 static struct timeout_item*
 ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
 			       timeout_cb_t cb, void *data)
 {
 	struct timeout_item *item, *tmp;

 	LASSERT(mutex_is_locked(&pinger_mutex));

 	list_for_each_entry(item, &timeout_list, ti_chain)
 		if (item->ti_event == event)
 			goto out;

 	item = ptlrpc_new_timeout(time, event, cb, data);
 	if (item) {
 		list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
 			if (tmp->ti_timeout < time) {
 				list_add(&item->ti_chain, &tmp->ti_chain);
 				goto out;
 			}
 		}
 		list_add(&item->ti_chain, &timeout_list);
 	}
 out:
 	return item;
 }

 /* Add a client_obd to the timeout event list, when timeout(@time)
  * happens, the callback(@cb) will be called.
  */
 int ptlrpc_add_timeout_client(int time, enum timeout_event event,
 			      timeout_cb_t cb, void *data,
 			      struct list_head *obd_list)
 {
 	struct timeout_item *ti;

 	mutex_lock(&pinger_mutex);
 	ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
 	if (!ti) {
 		mutex_unlock(&pinger_mutex);
 		return -EINVAL;
 	}
 	list_add(obd_list, &ti->ti_obd_list);
 	mutex_unlock(&pinger_mutex);
 	return 0;
 }
 EXPORT_SYMBOL(ptlrpc_add_timeout_client);

 int ptlrpc_del_timeout_client(struct list_head *obd_list,
 			      enum timeout_event event)
 {
 	struct timeout_item *ti = NULL, *item;

 	if (list_empty(obd_list))
 		return 0;
 	mutex_lock(&pinger_mutex);
 	list_del_init(obd_list);
 	/**
 	 * If there are no obd attached to the timeout event
 	 * list, remove this timeout event from the pinger
 	 */
 	list_for_each_entry(item, &timeout_list, ti_chain) {
 		if (item->ti_event == event) {
 			ti = item;
 			break;
 		}
 	}
 	if (list_empty(&ti->ti_obd_list)) {
 		list_del(&ti->ti_chain);
 		kfree(ti);
 	}
 	mutex_unlock(&pinger_mutex);
 	return 0;
 }
 EXPORT_SYMBOL(ptlrpc_del_timeout_client);

 static int ptlrpc_pinger_remove_timeouts(void)
 {
 	struct timeout_item *item, *tmp;

 	mutex_lock(&pinger_mutex);
 	list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
 		LASSERT(list_empty(&item->ti_obd_list));
 		list_del(&item->ti_chain);
 		kfree(item);
 	}
 	mutex_unlock(&pinger_mutex);
 	return 0;
 }

 void ptlrpc_pinger_wake_up(void)
 {
 	thread_add_flags(&pinger_thread, SVC_EVENT);
 	wake_up(&pinger_thread.t_ctl_waitq);
 }
	/*
	* 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) 2011, 2015, Intel Corporation.
	*/
	/*
	* This file is part of Lustre, http://www.lustre.org/
	* Lustre is a trademark of Sun Microsystems, Inc.
	*
	* lustre/ptlrpc/pinger.c
	*
	* Portal-RPC reconnection and replay operations, for use in recovery.
	*/

	#define DEBUG_SUBSYSTEM S_RPC

	#include <obd_support.h>
	#include <obd_class.h>
	#include "ptlrpc_internal.h"

	struct mutex pinger_mutex;
	static LIST_HEAD(pinger_imports);
	static struct list_head timeout_list = LIST_HEAD_INIT(timeout_list);

	struct ptlrpc_request *
	ptlrpc_prep_ping(struct obd_import *imp)
	{
	struct ptlrpc_request *req;

	req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING,
	LUSTRE_OBD_VERSION, OBD_PING);
	if (req) {
	ptlrpc_request_set_replen(req);
	req->rq_no_resend = 1;
	req->rq_no_delay = 1;
	}
	return req;
	}

	int ptlrpc_obd_ping(struct obd_device *obd)
	{
	int rc;
	struct ptlrpc_request *req;

	req = ptlrpc_prep_ping(obd->u.cli.cl_import);
	if (!req)
	return -ENOMEM;

	req->rq_send_state = LUSTRE_IMP_FULL;

	rc = ptlrpc_queue_wait(req);

	ptlrpc_req_finished(req);

	return rc;
	}
	EXPORT_SYMBOL(ptlrpc_obd_ping);

	static int ptlrpc_ping(struct obd_import *imp)
	{
	struct ptlrpc_request *req;

	req = ptlrpc_prep_ping(imp);
	if (!req) {
	CERROR("OOM trying to ping %s->%s\n",
	imp->imp_obd->obd_uuid.uuid,
	obd2cli_tgt(imp->imp_obd));
	return -ENOMEM;
	}

	DEBUG_REQ(D_INFO, req, "pinging %s->%s",
	imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
	ptlrpcd_add_req(req);

	return 0;
	}

	static void ptlrpc_update_next_ping(struct obd_import *imp, int soon)
	{
	int time = soon ? PING_INTERVAL_SHORT : PING_INTERVAL;

	if (imp->imp_state == LUSTRE_IMP_DISCON) {
	int dtime = max_t(int, CONNECTION_SWITCH_MIN,
	AT_OFF ? 0 :
	at_get(&imp->imp_at.iat_net_latency));
	time = min(time, dtime);
	}
	imp->imp_next_ping = cfs_time_shift(time);
	}

	static inline int imp_is_deactive(struct obd_import *imp)
	{
	return (imp->imp_deactive \|\|
	OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_IMP_DEACTIVE));
	}

	static inline int ptlrpc_next_reconnect(struct obd_import *imp)
	{
	if (imp->imp_server_timeout)
	return cfs_time_shift(obd_timeout / 2);
	else
	return cfs_time_shift(obd_timeout);
	}

	static long pinger_check_timeout(unsigned long time)
	{
	struct timeout_item *item;
	unsigned long timeout = PING_INTERVAL;

	/* The timeout list is a increase order sorted list */
	mutex_lock(&pinger_mutex);
	list_for_each_entry(item, &timeout_list, ti_chain) {
	int ti_timeout = item->ti_timeout;

	if (timeout > ti_timeout)
	timeout = ti_timeout;
	break;
	}
	mutex_unlock(&pinger_mutex);

	return cfs_time_sub(cfs_time_add(time, cfs_time_seconds(timeout)),
	cfs_time_current());
	}

	static bool ir_up;

	void ptlrpc_pinger_ir_up(void)
	{
	CDEBUG(D_HA, "IR up\n");
	ir_up = true;
	}
	EXPORT_SYMBOL(ptlrpc_pinger_ir_up);

	void ptlrpc_pinger_ir_down(void)
	{
	CDEBUG(D_HA, "IR down\n");
	ir_up = false;
	}
	EXPORT_SYMBOL(ptlrpc_pinger_ir_down);

	static void ptlrpc_pinger_process_import(struct obd_import *imp,
	unsigned long this_ping)
	{
	int level;
	int force;
	int force_next;
	int suppress;

	spin_lock(&imp->imp_lock);

	level = imp->imp_state;
	force = imp->imp_force_verify;
	force_next = imp->imp_force_next_verify;
	/*
	* This will be used below only if the import is "FULL".
	*/
	suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);

	imp->imp_force_verify = 0;

	if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
	!force) {
	spin_unlock(&imp->imp_lock);
	return;
	}

	imp->imp_force_next_verify = 0;

	spin_unlock(&imp->imp_lock);

	CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u force %u force_next %u deactive %u pingable %u suppress %u\n",
	imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
	ptlrpc_import_state_name(level), level, force, force_next,
	imp->imp_deactive, imp->imp_pingable, suppress);

	if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
	/* wait for a while before trying recovery again */
	imp->imp_next_ping = ptlrpc_next_reconnect(imp);
	if (!imp->imp_no_pinger_recover)
	ptlrpc_initiate_recovery(imp);
	} else if (level != LUSTRE_IMP_FULL \|\|
	imp->imp_obd->obd_no_recov \|\|
	imp_is_deactive(imp)) {
	CDEBUG(D_HA, "%s->%s: not pinging (in recovery or recovery disabled: %s)\n",
	imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
	ptlrpc_import_state_name(level));
	if (force) {
	spin_lock(&imp->imp_lock);
	imp->imp_force_verify = 1;
	spin_unlock(&imp->imp_lock);
	}
	} else if ((imp->imp_pingable && !suppress) \|\| force_next \|\| force) {
	ptlrpc_ping(imp);
	}
	}

	static int ptlrpc_pinger_main(void *arg)
	{
	struct ptlrpc_thread *thread = arg;

	/* Record that the thread is running */
	thread_set_flags(thread, SVC_RUNNING);
	wake_up(&thread->t_ctl_waitq);

	/* And now, loop forever, pinging as needed. */
	while (1) {
	unsigned long this_ping = cfs_time_current();
	struct l_wait_info lwi;
	long time_to_next_wake;
	struct timeout_item *item;
	struct list_head *iter;

	mutex_lock(&pinger_mutex);
	list_for_each_entry(item, &timeout_list, ti_chain) {
	item->ti_cb(item, item->ti_cb_data);
	}
	list_for_each(iter, &pinger_imports) {
	struct obd_import *imp =
	list_entry(iter, struct obd_import,
	imp_pinger_chain);

	ptlrpc_pinger_process_import(imp, this_ping);
	/* obd_timeout might have changed */
	if (imp->imp_pingable && imp->imp_next_ping &&
	cfs_time_after(imp->imp_next_ping,
	cfs_time_add(this_ping,
	cfs_time_seconds(PING_INTERVAL))))
	ptlrpc_update_next_ping(imp, 0);
	}
	mutex_unlock(&pinger_mutex);

	/* Wait until the next ping time, or until we're stopped. */
	time_to_next_wake = pinger_check_timeout(this_ping);
	/* The ping sent by ptlrpc_send_rpc may get sent out
	* say .01 second after this.
	* ptlrpc_pinger_sending_on_import will then set the
	* next ping time to next_ping + .01 sec, which means
	* we will SKIP the next ping at next_ping, and the
	* ping will get sent 2 timeouts from now! Beware.
	*/
	CDEBUG(D_INFO, "next wakeup in " CFS_DURATION_T " (%ld)\n",
	time_to_next_wake,
	cfs_time_add(this_ping,
	cfs_time_seconds(PING_INTERVAL)));
	if (time_to_next_wake > 0) {
	lwi = LWI_TIMEOUT(max_t(long, time_to_next_wake,
	cfs_time_seconds(1)),
	NULL, NULL);
	l_wait_event(thread->t_ctl_waitq,
	thread_is_stopping(thread) \|\|
	thread_is_event(thread),
	&lwi);
	if (thread_test_and_clear_flags(thread, SVC_STOPPING))
	break;
	/* woken after adding import to reset timer */
	thread_test_and_clear_flags(thread, SVC_EVENT);
	}
	}

	thread_set_flags(thread, SVC_STOPPED);
	wake_up(&thread->t_ctl_waitq);

	CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
	return 0;
	}

	static struct ptlrpc_thread pinger_thread;

	int ptlrpc_start_pinger(void)
	{
	struct l_wait_info lwi = { 0 };
	struct task_struct *task;
	int rc;

	if (!thread_is_init(&pinger_thread) &&
	!thread_is_stopped(&pinger_thread))
	return -EALREADY;

	init_waitqueue_head(&pinger_thread.t_ctl_waitq);

	strcpy(pinger_thread.t_name, "ll_ping");

	task = kthread_run(ptlrpc_pinger_main, &pinger_thread,
	pinger_thread.t_name);
	if (IS_ERR(task)) {
	rc = PTR_ERR(task);
	CERROR("cannot start pinger thread: rc = %d\n", rc);
	return rc;
	}
	l_wait_event(pinger_thread.t_ctl_waitq,
	thread_is_running(&pinger_thread), &lwi);

	return 0;
	}

	static int ptlrpc_pinger_remove_timeouts(void);

	int ptlrpc_stop_pinger(void)
	{
	struct l_wait_info lwi = { 0 };
	int rc = 0;

	if (thread_is_init(&pinger_thread) \|\|
	thread_is_stopped(&pinger_thread))
	return -EALREADY;

	ptlrpc_pinger_remove_timeouts();
	thread_set_flags(&pinger_thread, SVC_STOPPING);
	wake_up(&pinger_thread.t_ctl_waitq);

	l_wait_event(pinger_thread.t_ctl_waitq,
	thread_is_stopped(&pinger_thread), &lwi);

	return rc;
	}

	void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
	{
	ptlrpc_update_next_ping(imp, 0);
	}

	void ptlrpc_pinger_commit_expected(struct obd_import *imp)
	{
	ptlrpc_update_next_ping(imp, 1);
	assert_spin_locked(&imp->imp_lock);
	/*
	* Avoid reading stale imp_connect_data. When not sure if pings are
	* expected or not on next connection, we assume they are not and force
	* one anyway to guarantee the chance of updating
	* imp_peer_committed_transno.
	*/
	if (imp->imp_state != LUSTRE_IMP_FULL \|\|
	OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
	imp->imp_force_next_verify = 1;
	}

	int ptlrpc_pinger_add_import(struct obd_import *imp)
	{
	if (!list_empty(&imp->imp_pinger_chain))
	return -EALREADY;

	mutex_lock(&pinger_mutex);
	CDEBUG(D_HA, "adding pingable import %s->%s\n",
	imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
	/* if we add to pinger we want recovery on this import */
	imp->imp_obd->obd_no_recov = 0;
	ptlrpc_update_next_ping(imp, 0);
	/* XXX sort, blah blah */
	list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
	class_import_get(imp);

	ptlrpc_pinger_wake_up();
	mutex_unlock(&pinger_mutex);

	return 0;
	}
	EXPORT_SYMBOL(ptlrpc_pinger_add_import);

	int ptlrpc_pinger_del_import(struct obd_import *imp)
	{
	if (list_empty(&imp->imp_pinger_chain))
	return -ENOENT;

	mutex_lock(&pinger_mutex);
	list_del_init(&imp->imp_pinger_chain);
	CDEBUG(D_HA, "removing pingable import %s->%s\n",
	imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
	/* if we remove from pinger we don't want recovery on this import */
	imp->imp_obd->obd_no_recov = 1;
	class_import_put(imp);
	mutex_unlock(&pinger_mutex);
	return 0;
	}
	EXPORT_SYMBOL(ptlrpc_pinger_del_import);

	/**
	* Register a timeout callback to the pinger list, and the callback will
	* be called when timeout happens.
	*/
	static struct timeout_item *ptlrpc_new_timeout(int time,
	enum timeout_event event,
	timeout_cb_t cb, void *data)
	{
	struct timeout_item *ti;

	ti = kzalloc(sizeof(*ti), GFP_NOFS);
	if (!ti)
	return NULL;

	INIT_LIST_HEAD(&ti->ti_obd_list);
	INIT_LIST_HEAD(&ti->ti_chain);
	ti->ti_timeout = time;
	ti->ti_event = event;
	ti->ti_cb = cb;
	ti->ti_cb_data = data;

	return ti;
	}

	/**
	* Register timeout event on the pinger thread.
	* Note: the timeout list is an sorted list with increased timeout value.
	*/
	static struct timeout_item*
	ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
	timeout_cb_t cb, void *data)
	{
	struct timeout_item item, tmp;

	LASSERT(mutex_is_locked(&pinger_mutex));

	list_for_each_entry(item, &timeout_list, ti_chain)
	if (item->ti_event == event)
	goto out;

	item = ptlrpc_new_timeout(time, event, cb, data);
	if (item) {
	list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
	if (tmp->ti_timeout < time) {
	list_add(&item->ti_chain, &tmp->ti_chain);
	goto out;
	}
	}
	list_add(&item->ti_chain, &timeout_list);
	}
	out:
	return item;
	}

	/* Add a client_obd to the timeout event list, when timeout(@time)
	* happens, the callback(@cb) will be called.
	*/
	int ptlrpc_add_timeout_client(int time, enum timeout_event event,
	timeout_cb_t cb, void *data,
	struct list_head *obd_list)
	{
	struct timeout_item *ti;

	mutex_lock(&pinger_mutex);
	ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
	if (!ti) {
	mutex_unlock(&pinger_mutex);
	return -EINVAL;
	}
	list_add(obd_list, &ti->ti_obd_list);
	mutex_unlock(&pinger_mutex);
	return 0;
	}
	EXPORT_SYMBOL(ptlrpc_add_timeout_client);

	int ptlrpc_del_timeout_client(struct list_head *obd_list,
	enum timeout_event event)
	{
	struct timeout_item ti = NULL, item;

	if (list_empty(obd_list))
	return 0;
	mutex_lock(&pinger_mutex);
	list_del_init(obd_list);
	/**
	* If there are no obd attached to the timeout event
	* list, remove this timeout event from the pinger
	*/
	list_for_each_entry(item, &timeout_list, ti_chain) {
	if (item->ti_event == event) {
	ti = item;
	break;
	}
	}
	if (list_empty(&ti->ti_obd_list)) {
	list_del(&ti->ti_chain);
	kfree(ti);
	}
	mutex_unlock(&pinger_mutex);
	return 0;
	}
	EXPORT_SYMBOL(ptlrpc_del_timeout_client);

	static int ptlrpc_pinger_remove_timeouts(void)
	{
	struct timeout_item item, tmp;

	mutex_lock(&pinger_mutex);
	list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
	LASSERT(list_empty(&item->ti_obd_list));
	list_del(&item->ti_chain);
	kfree(item);
	}
	mutex_unlock(&pinger_mutex);
	return 0;
	}

	void ptlrpc_pinger_wake_up(void)
	{
	thread_add_flags(&pinger_thread, SVC_EVENT);
	wake_up(&pinger_thread.t_ctl_waitq);
	}