/**************************************************************************
*                                                                         *
* Copyright (c) International Business Machines Corp., 2005               *
*                                                                         *
* This program is free software; you can redistribute it and/or modify    *
* it under the terms of the GNU General Public License as published by    *
* the Free Software Foundation; either version 2 of the License, or       *
* (at your option) any later version.                                     *
*                                                                         *
* 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 for more details.                            *
*                                                                         *
* You should have received a copy of the GNU General Public License       *
* along with this program; if not, write to the Free Software             *
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
*                                                                         *
* Author:  Guanglei Li (guanglei@cn.ibm.com)                              *
**************************************************************************/

/************************************************************
* Probe the event when a request is retrieved from request  *
* queue(dispatched to corresponding device), the event when *
* a request is added by block layer into the request queue, *
* and the event is removed by from the request queue        *
************************************************************/
probe addevent.ioscheduler
	= addevent.ioscheduler.elv_next_request, 
	addevent.ioscheduler.elv_add_request,
	addevent.ioscheduler.elv_remove_request
{
}

/* when a request is retrieved from request queue */
probe addevent.ioscheduler.elv_next_request
	=  kernel.function("elv_next_request")
{
	if(filter_by_pid() == 1 ) {
		log_tracedata_common(HOOKID_IOSCHED_NEXT_REQ)
		log_ioscheduler_tracedata_extra_elv_next($q)
	}
}


/* when a request is added to the request queue */
probe addevent.ioscheduler.elv_add_request
	= kernel.function("__elv_add_request")
{
	if(filter_by_pid() == 1 ) {
		log_tracedata_common(HOOKID_IOSCHED_ADD_REQ)
		log_ioscheduler_tracedata_extra_others($q, $rq)
	}
}

/* when a request is removed from the request queue */
probe addevent.ioscheduler.elv_remove_request
	= kernel.function("elv_remove_request")
{
	if(filter_by_pid() == 1 ) {
		log_tracedata_common(HOOKID_IOSCHED_REMOVE_REQ)
		log_ioscheduler_tracedata_extra_others($q, $rq)
	}
}


%{
#include <linux/blkdev.h>
#include <linux/elevator.h>
%}

/* log the data specific to __elv_add_request and elv_remove_request,
  for kernel == 2.6.9. Need to confirm the actual kernel version range
  i.e. kernel_v <= 2.6.x.  */
%( kernel_v == "2.6.9" %?
function log_ioscheduler_tracedata_extra_others(var_q:long, var_rq:long)
%{
	struct request *rq = (struct request *)((long)THIS->var_rq);
	struct request_queue *q = (struct request_queue *)((long)THIS->var_q);
	
	/* elevator name|major|minor| */
	_stp_printf("%s|%ld|%ld|", q->elevator.elevator_name, rq->rq_disk->major, rq->rq_disk->first_minor); 
%}

/* log the data specific to __elv_add_request and elv_remove_request,
  for kernel > 2.6.9. The exact version need to be determined. */
%:
function log_ioscheduler_tracedata_extra_others(var_q:long, var_rq:long)
%{
	struct request *rq = (struct request *)((long)THIS->var_rq);
	struct request_queue *q = (struct request_queue *)((long)THIS->var_q);
	
	/* elevator name|major|minor| */
	_stp_printf("%s|%ld|%ld|", q->elevator->elevator_type->elevator_name, rq->rq_disk->major, rq->rq_disk->first_minor); 
%}
%)

/* log the data specific to elv_next_request, for kernel == 2.6.9 */
%( kernel_v == "2.6.9" %? 
function log_ioscheduler_tracedata_extra_elv_next(var:long)
%{

	struct request_queue *q;
	struct request *rq;

	q = (struct request_queue *)((long)THIS->var);

	/* If there is a request in the request queue:
		elevator name|major|minor|
	   if there is no request in the request queue:
		elevator name|empty| 
	*/
	if(list_empty(&(q->queue_head))) {
		_stp_printf("%s|empty|", q->elevator.elevator_name);
	} else  {
		rq = list_entry_rq(q->queue_head.next);
		_stp_printf("%s|%ld|%ld", q->elevator.elevator_name, rq->rq_disk->major, rq->rq_disk->first_minor); 
	}
%}

%:
/* log the data specific to elv_next_request , for kernel > 2.6.9*/
function log_ioscheduler_tracedata_extra_elv_next(var:long)
%{

	struct request_queue *q;
	struct request *rq;

	q = (struct request_queue *)((long)THIS->var);

	/* If there is a request in the request queue:
		elevator name|major|minor|
	   if there is no request in the request queue:
		elevator name|empty| 
	*/
	if(list_empty(&(q->queue_head)))  {
		_stp_printf("%s|empty|", q->elevator->elevator_type->elevator_name);
	} else  {
		rq = list_entry_rq(q->queue_head.next);
		_stp_printf("%s|%ld|%ld", q->elevator->elevator_type->elevator_name, rq->rq_disk->major, rq->rq_disk->first_minor); 
	}
%}
%)