kernel/rtmutex-tester.c - maze/linux - Git at Google

 /*
  * RT-Mutex-tester: scriptable tester for rt mutexes
  *
  * started by Thomas Gleixner:
  *
  *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
  *
  */
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/sysdev.h>
 #include <linux/timer.h>
 #include <linux/freezer.h>

 #include "rtmutex.h"

 #define MAX_RT_TEST_THREADS	8
 #define MAX_RT_TEST_MUTEXES	8

 static spinlock_t rttest_lock;
 static atomic_t rttest_event;

 struct test_thread_data {
 	int			opcode;
 	int			opdata;
 	int			mutexes[MAX_RT_TEST_MUTEXES];
 	int			bkl;
 	int			event;
 	struct sys_device	sysdev;
 };

 static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
 static struct task_struct *threads[MAX_RT_TEST_THREADS];
 static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];

 enum test_opcodes {
 	RTTEST_NOP = 0,
 	RTTEST_SCHEDOT,		/* 1 Sched other, data = nice */
 	RTTEST_SCHEDRT,		/* 2 Sched fifo, data = prio */
 	RTTEST_LOCK,		/* 3 Lock uninterruptible, data = lockindex */
 	RTTEST_LOCKNOWAIT,	/* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
 	RTTEST_LOCKINT,		/* 5 Lock interruptible, data = lockindex */
 	RTTEST_LOCKINTNOWAIT,	/* 6 Lock interruptible no wait in wakeup, data = lockindex */
 	RTTEST_LOCKCONT,	/* 7 Continue locking after the wakeup delay */
 	RTTEST_UNLOCK,		/* 8 Unlock, data = lockindex */
 	RTTEST_LOCKBKL,		/* 9 Lock BKL */
 	RTTEST_UNLOCKBKL,	/* 10 Unlock BKL */
 	RTTEST_SIGNAL,		/* 11 Signal other test thread, data = thread id */
 	RTTEST_RESETEVENT = 98,	/* 98 Reset event counter */
 	RTTEST_RESET = 99,	/* 99 Reset all pending operations */
 };

 static int handle_op(struct test_thread_data *td, int lockwakeup)
 {
 	int i, id, ret = -EINVAL;

 	switch(td->opcode) {

 	case RTTEST_NOP:
 		return 0;

 	case RTTEST_LOCKCONT:
 		td->mutexes[td->opdata] = 1;
 		td->event = atomic_add_return(1, &rttest_event);
 		return 0;

 	case RTTEST_RESET:
 		for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
 			if (td->mutexes[i] == 4) {
 				rt_mutex_unlock(&mutexes[i]);
 				td->mutexes[i] = 0;
 			}
 		}

 		if (!lockwakeup && td->bkl == 4) {
 			unlock_kernel();
 			td->bkl = 0;
 		}
 		return 0;

 	case RTTEST_RESETEVENT:
 		atomic_set(&rttest_event, 0);
 		return 0;

 	default:
 		if (lockwakeup)
 			return ret;
 	}

 	switch(td->opcode) {

 	case RTTEST_LOCK:
 	case RTTEST_LOCKNOWAIT:
 		id = td->opdata;
 		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
 			return ret;

 		td->mutexes[id] = 1;
 		td->event = atomic_add_return(1, &rttest_event);
 		rt_mutex_lock(&mutexes[id]);
 		td->event = atomic_add_return(1, &rttest_event);
 		td->mutexes[id] = 4;
 		return 0;

 	case RTTEST_LOCKINT:
 	case RTTEST_LOCKINTNOWAIT:
 		id = td->opdata;
 		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
 			return ret;

 		td->mutexes[id] = 1;
 		td->event = atomic_add_return(1, &rttest_event);
 		ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
 		td->event = atomic_add_return(1, &rttest_event);
 		td->mutexes[id] = ret ? 0 : 4;
 		return ret ? -EINTR : 0;

 	case RTTEST_UNLOCK:
 		id = td->opdata;
 		if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
 			return ret;

 		td->event = atomic_add_return(1, &rttest_event);
 		rt_mutex_unlock(&mutexes[id]);
 		td->event = atomic_add_return(1, &rttest_event);
 		td->mutexes[id] = 0;
 		return 0;

 	case RTTEST_LOCKBKL:
 		if (td->bkl)
 			return 0;
 		td->bkl = 1;
 		lock_kernel();
 		td->bkl = 4;
 		return 0;

 	case RTTEST_UNLOCKBKL:
 		if (td->bkl != 4)
 			break;
 		unlock_kernel();
 		td->bkl = 0;
 		return 0;

 	default:
 		break;
 	}
 	return ret;
 }

 /*
  * Schedule replacement for rtsem_down(). Only called for threads with
  * PF_MUTEX_TESTER set.
  *
  * This allows us to have finegrained control over the event flow.
  *
  */
 void schedule_rt_mutex_test(struct rt_mutex *mutex)
 {
 	int tid, op, dat;
 	struct test_thread_data *td;

 	/* We have to lookup the task */
 	for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
 		if (threads[tid] == current)
 			break;
 	}

 	BUG_ON(tid == MAX_RT_TEST_THREADS);

 	td = &thread_data[tid];

 	op = td->opcode;
 	dat = td->opdata;

 	switch (op) {
 	case RTTEST_LOCK:
 	case RTTEST_LOCKINT:
 	case RTTEST_LOCKNOWAIT:
 	case RTTEST_LOCKINTNOWAIT:
 		if (mutex != &mutexes[dat])
 			break;

 		if (td->mutexes[dat] != 1)
 			break;

 		td->mutexes[dat] = 2;
 		td->event = atomic_add_return(1, &rttest_event);
 		break;

 	case RTTEST_LOCKBKL:
 	default:
 		break;
 	}

 	schedule();


 	switch (op) {
 	case RTTEST_LOCK:
 	case RTTEST_LOCKINT:
 		if (mutex != &mutexes[dat])
 			return;

 		if (td->mutexes[dat] != 2)
 			return;

 		td->mutexes[dat] = 3;
 		td->event = atomic_add_return(1, &rttest_event);
 		break;

 	case RTTEST_LOCKNOWAIT:
 	case RTTEST_LOCKINTNOWAIT:
 		if (mutex != &mutexes[dat])
 			return;

 		if (td->mutexes[dat] != 2)
 			return;

 		td->mutexes[dat] = 1;
 		td->event = atomic_add_return(1, &rttest_event);
 		return;

 	case RTTEST_LOCKBKL:
 		return;
 	default:
 		return;
 	}

 	td->opcode = 0;

 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);

 		if (td->opcode > 0) {
 			int ret;

 			set_current_state(TASK_RUNNING);
 			ret = handle_op(td, 1);
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (td->opcode == RTTEST_LOCKCONT)
 				break;
 			td->opcode = ret;
 		}

 		/* Wait for the next command to be executed */
 		schedule();
 	}

 	/* Restore previous command and data */
 	td->opcode = op;
 	td->opdata = dat;
 }

 static int test_func(void *data)
 {
 	struct test_thread_data *td = data;
 	int ret;

 	current->flags |= PF_MUTEX_TESTER;
 	set_freezable();
 	allow_signal(SIGHUP);

 	for(;;) {

 		set_current_state(TASK_INTERRUPTIBLE);

 		if (td->opcode > 0) {
 			set_current_state(TASK_RUNNING);
 			ret = handle_op(td, 0);
 			set_current_state(TASK_INTERRUPTIBLE);
 			td->opcode = ret;
 		}

 		/* Wait for the next command to be executed */
 		schedule();
 		try_to_freeze();

 		if (signal_pending(current))
 			flush_signals(current);

 		if(kthread_should_stop())
 			break;
 	}
 	return 0;
 }

 /**
  * sysfs_test_command - interface for test commands
  * @dev:	thread reference
  * @buf:	command for actual step
  * @count:	length of buffer
  *
  * command syntax:
  *
  * opcode:data
  */
 static ssize_t sysfs_test_command(struct sys_device *dev, struct sysdev_attribute *attr,
 				  const char *buf, size_t count)
 {
 	struct sched_param schedpar;
 	struct test_thread_data *td;
 	char cmdbuf[32];
 	int op, dat, tid, ret;

 	td = container_of(dev, struct test_thread_data, sysdev);
 	tid = td->sysdev.id;

 	/* strings from sysfs write are not 0 terminated! */
 	if (count >= sizeof(cmdbuf))
 		return -EINVAL;

 	/* strip of \n: */
 	if (buf[count-1] == '\n')
 		count--;
 	if (count < 1)
 		return -EINVAL;

 	memcpy(cmdbuf, buf, count);
 	cmdbuf[count] = 0;

 	if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
 		return -EINVAL;

 	switch (op) {
 	case RTTEST_SCHEDOT:
 		schedpar.sched_priority = 0;
 		ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
 		if (ret)
 			return ret;
 		set_user_nice(current, 0);
 		break;

 	case RTTEST_SCHEDRT:
 		schedpar.sched_priority = dat;
 		ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
 		if (ret)
 			return ret;
 		break;

 	case RTTEST_SIGNAL:
 		send_sig(SIGHUP, threads[tid], 0);
 		break;

 	default:
 		if (td->opcode > 0)
 			return -EBUSY;
 		td->opdata = dat;
 		td->opcode = op;
 		wake_up_process(threads[tid]);
 	}

 	return count;
 }

 /**
  * sysfs_test_status - sysfs interface for rt tester
  * @dev:	thread to query
  * @buf:	char buffer to be filled with thread status info
  */
 static ssize_t sysfs_test_status(struct sys_device *dev, struct sysdev_attribute *attr,
 				 char *buf)
 {
 	struct test_thread_data *td;
 	struct task_struct *tsk;
 	char *curr = buf;
 	int i;

 	td = container_of(dev, struct test_thread_data, sysdev);
 	tsk = threads[td->sysdev.id];

 	spin_lock(&rttest_lock);

 	curr += sprintf(curr,
 		"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, K: %d, M:",
 		td->opcode, td->event, tsk->state,
 			(MAX_RT_PRIO - 1) - tsk->prio,
 			(MAX_RT_PRIO - 1) - tsk->normal_prio,
 		tsk->pi_blocked_on, td->bkl);

 	for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
 		curr += sprintf(curr, "%d", td->mutexes[i]);

 	spin_unlock(&rttest_lock);

 	curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
 			mutexes[td->sysdev.id].owner);

 	return curr - buf;
 }

 static SYSDEV_ATTR(status, 0600, sysfs_test_status, NULL);
 static SYSDEV_ATTR(command, 0600, NULL, sysfs_test_command);

 static struct sysdev_class rttest_sysclass = {
 	.name = "rttest",
 };

 static int init_test_thread(int id)
 {
 	thread_data[id].sysdev.cls = &rttest_sysclass;
 	thread_data[id].sysdev.id = id;

 	threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
 	if (IS_ERR(threads[id]))
 		return PTR_ERR(threads[id]);

 	return sysdev_register(&thread_data[id].sysdev);
 }

 static int init_rttest(void)
 {
 	int ret, i;

 	spin_lock_init(&rttest_lock);

 	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
 		rt_mutex_init(&mutexes[i]);

 	ret = sysdev_class_register(&rttest_sysclass);
 	if (ret)
 		return ret;

 	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
 		ret = init_test_thread(i);
 		if (ret)
 			break;
 		ret = sysdev_create_file(&thread_data[i].sysdev, &attr_status);
 		if (ret)
 			break;
 		ret = sysdev_create_file(&thread_data[i].sysdev, &attr_command);
 		if (ret)
 			break;
 	}

 	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );

 	return ret;
 }

 device_initcall(init_rttest);
	/*
	* RT-Mutex-tester: scriptable tester for rt mutexes
	*
	* started by Thomas Gleixner:
	*
	* Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
	*
	*/
	#include <linux/kthread.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/smp_lock.h>
	#include <linux/spinlock.h>
	#include <linux/sysdev.h>
	#include <linux/timer.h>
	#include <linux/freezer.h>

	#include "rtmutex.h"

	#define MAX_RT_TEST_THREADS 8
	#define MAX_RT_TEST_MUTEXES 8

	static spinlock_t rttest_lock;
	static atomic_t rttest_event;

	struct test_thread_data {
	int opcode;
	int opdata;
	int mutexes[MAX_RT_TEST_MUTEXES];
	int bkl;
	int event;
	struct sys_device sysdev;
	};

	static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
	static struct task_struct *threads[MAX_RT_TEST_THREADS];
	static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];

	enum test_opcodes {
	RTTEST_NOP = 0,
	RTTEST_SCHEDOT, /* 1 Sched other, data = nice */
	RTTEST_SCHEDRT, /* 2 Sched fifo, data = prio */
	RTTEST_LOCK, /* 3 Lock uninterruptible, data = lockindex */
	RTTEST_LOCKNOWAIT, /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
	RTTEST_LOCKINT, /* 5 Lock interruptible, data = lockindex */
	RTTEST_LOCKINTNOWAIT, /* 6 Lock interruptible no wait in wakeup, data = lockindex */
	RTTEST_LOCKCONT, /* 7 Continue locking after the wakeup delay */
	RTTEST_UNLOCK, /* 8 Unlock, data = lockindex */
	RTTEST_LOCKBKL, /* 9 Lock BKL */
	RTTEST_UNLOCKBKL, /* 10 Unlock BKL */
	RTTEST_SIGNAL, /* 11 Signal other test thread, data = thread id */
	RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
	RTTEST_RESET = 99, /* 99 Reset all pending operations */
	};

	static int handle_op(struct test_thread_data *td, int lockwakeup)
	{
	int i, id, ret = -EINVAL;

	switch(td->opcode) {

	case RTTEST_NOP:
	return 0;

	case RTTEST_LOCKCONT:
	td->mutexes[td->opdata] = 1;
	td->event = atomic_add_return(1, &rttest_event);
	return 0;

	case RTTEST_RESET:
	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
	if (td->mutexes[i] == 4) {
	rt_mutex_unlock(&mutexes[i]);
	td->mutexes[i] = 0;
	}
	}

	if (!lockwakeup && td->bkl == 4) {
	unlock_kernel();
	td->bkl = 0;
	}
	return 0;

	case RTTEST_RESETEVENT:
	atomic_set(&rttest_event, 0);
	return 0;

	default:
	if (lockwakeup)
	return ret;
	}

	switch(td->opcode) {

	case RTTEST_LOCK:
	case RTTEST_LOCKNOWAIT:
	id = td->opdata;
	if (id < 0 \|\| id >= MAX_RT_TEST_MUTEXES)
	return ret;

	td->mutexes[id] = 1;
	td->event = atomic_add_return(1, &rttest_event);
	rt_mutex_lock(&mutexes[id]);
	td->event = atomic_add_return(1, &rttest_event);
	td->mutexes[id] = 4;
	return 0;

	case RTTEST_LOCKINT:
	case RTTEST_LOCKINTNOWAIT:
	id = td->opdata;
	if (id < 0 \|\| id >= MAX_RT_TEST_MUTEXES)
	return ret;

	td->mutexes[id] = 1;
	td->event = atomic_add_return(1, &rttest_event);
	ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
	td->event = atomic_add_return(1, &rttest_event);
	td->mutexes[id] = ret ? 0 : 4;
	return ret ? -EINTR : 0;

	case RTTEST_UNLOCK:
	id = td->opdata;
	if (id < 0 \|\| id >= MAX_RT_TEST_MUTEXES \|\| td->mutexes[id] != 4)
	return ret;

	td->event = atomic_add_return(1, &rttest_event);
	rt_mutex_unlock(&mutexes[id]);
	td->event = atomic_add_return(1, &rttest_event);
	td->mutexes[id] = 0;
	return 0;

	case RTTEST_LOCKBKL:
	if (td->bkl)
	return 0;
	td->bkl = 1;
	lock_kernel();
	td->bkl = 4;
	return 0;

	case RTTEST_UNLOCKBKL:
	if (td->bkl != 4)
	break;
	unlock_kernel();
	td->bkl = 0;
	return 0;

	default:
	break;
	}
	return ret;
	}

	/*
	* Schedule replacement for rtsem_down(). Only called for threads with
	* PF_MUTEX_TESTER set.
	*
	* This allows us to have finegrained control over the event flow.
	*
	*/
	void schedule_rt_mutex_test(struct rt_mutex *mutex)
	{
	int tid, op, dat;
	struct test_thread_data *td;

	/* We have to lookup the task */
	for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
	if (threads[tid] == current)
	break;
	}

	BUG_ON(tid == MAX_RT_TEST_THREADS);

	td = &thread_data[tid];

	op = td->opcode;
	dat = td->opdata;

	switch (op) {
	case RTTEST_LOCK:
	case RTTEST_LOCKINT:
	case RTTEST_LOCKNOWAIT:
	case RTTEST_LOCKINTNOWAIT:
	if (mutex != &mutexes[dat])
	break;

	if (td->mutexes[dat] != 1)
	break;

	td->mutexes[dat] = 2;
	td->event = atomic_add_return(1, &rttest_event);
	break;

	case RTTEST_LOCKBKL:
	default:
	break;
	}

	schedule();


	switch (op) {
	case RTTEST_LOCK:
	case RTTEST_LOCKINT:
	if (mutex != &mutexes[dat])
	return;

	if (td->mutexes[dat] != 2)
	return;

	td->mutexes[dat] = 3;
	td->event = atomic_add_return(1, &rttest_event);
	break;

	case RTTEST_LOCKNOWAIT:
	case RTTEST_LOCKINTNOWAIT:
	if (mutex != &mutexes[dat])
	return;

	if (td->mutexes[dat] != 2)
	return;

	td->mutexes[dat] = 1;
	td->event = atomic_add_return(1, &rttest_event);
	return;

	case RTTEST_LOCKBKL:
	return;
	default:
	return;
	}

	td->opcode = 0;

	for (;;) {
	set_current_state(TASK_INTERRUPTIBLE);

	if (td->opcode > 0) {
	int ret;

	set_current_state(TASK_RUNNING);
	ret = handle_op(td, 1);
	set_current_state(TASK_INTERRUPTIBLE);
	if (td->opcode == RTTEST_LOCKCONT)
	break;
	td->opcode = ret;
	}

	/* Wait for the next command to be executed */
	schedule();
	}

	/* Restore previous command and data */
	td->opcode = op;
	td->opdata = dat;
	}

	static int test_func(void *data)
	{
	struct test_thread_data *td = data;
	int ret;

	current->flags \|= PF_MUTEX_TESTER;
	set_freezable();
	allow_signal(SIGHUP);

	for(;;) {

	set_current_state(TASK_INTERRUPTIBLE);

	if (td->opcode > 0) {
	set_current_state(TASK_RUNNING);
	ret = handle_op(td, 0);
	set_current_state(TASK_INTERRUPTIBLE);
	td->opcode = ret;
	}

	/* Wait for the next command to be executed */
	schedule();
	try_to_freeze();

	if (signal_pending(current))
	flush_signals(current);

	if(kthread_should_stop())
	break;
	}
	return 0;
	}

	/**
	* sysfs_test_command - interface for test commands
	* @dev: thread reference
	* @buf: command for actual step
	* @count: length of buffer
	*
	* command syntax:
	*
	* opcode:data
	*/
	static ssize_t sysfs_test_command(struct sys_device dev, struct sysdev_attribute attr,
	const char *buf, size_t count)
	{
	struct sched_param schedpar;
	struct test_thread_data *td;
	char cmdbuf[32];
	int op, dat, tid, ret;

	td = container_of(dev, struct test_thread_data, sysdev);
	tid = td->sysdev.id;

	/* strings from sysfs write are not 0 terminated! */
	if (count >= sizeof(cmdbuf))
	return -EINVAL;

	/* strip of \n: */
	if (buf[count-1] == '\n')
	count--;
	if (count < 1)
	return -EINVAL;

	memcpy(cmdbuf, buf, count);
	cmdbuf[count] = 0;

	if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
	return -EINVAL;

	switch (op) {
	case RTTEST_SCHEDOT:
	schedpar.sched_priority = 0;
	ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
	if (ret)
	return ret;
	set_user_nice(current, 0);
	break;

	case RTTEST_SCHEDRT:
	schedpar.sched_priority = dat;
	ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
	if (ret)
	return ret;
	break;

	case RTTEST_SIGNAL:
	send_sig(SIGHUP, threads[tid], 0);
	break;

	default:
	if (td->opcode > 0)
	return -EBUSY;
	td->opdata = dat;
	td->opcode = op;
	wake_up_process(threads[tid]);
	}

	return count;
	}

	/**
	* sysfs_test_status - sysfs interface for rt tester
	* @dev: thread to query
	* @buf: char buffer to be filled with thread status info
	*/
	static ssize_t sysfs_test_status(struct sys_device dev, struct sysdev_attribute attr,
	char *buf)
	{
	struct test_thread_data *td;
	struct task_struct *tsk;
	char *curr = buf;
	int i;

	td = container_of(dev, struct test_thread_data, sysdev);
	tsk = threads[td->sysdev.id];

	spin_lock(&rttest_lock);

	curr += sprintf(curr,
	"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, K: %d, M:",
	td->opcode, td->event, tsk->state,
	(MAX_RT_PRIO - 1) - tsk->prio,
	(MAX_RT_PRIO - 1) - tsk->normal_prio,
	tsk->pi_blocked_on, td->bkl);

	for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
	curr += sprintf(curr, "%d", td->mutexes[i]);

	spin_unlock(&rttest_lock);

	curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
	mutexes[td->sysdev.id].owner);

	return curr - buf;
	}

	static SYSDEV_ATTR(status, 0600, sysfs_test_status, NULL);
	static SYSDEV_ATTR(command, 0600, NULL, sysfs_test_command);

	static struct sysdev_class rttest_sysclass = {
	.name = "rttest",
	};

	static int init_test_thread(int id)
	{
	thread_data[id].sysdev.cls = &rttest_sysclass;
	thread_data[id].sysdev.id = id;

	threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
	if (IS_ERR(threads[id]))
	return PTR_ERR(threads[id]);

	return sysdev_register(&thread_data[id].sysdev);
	}

	static int init_rttest(void)
	{
	int ret, i;

	spin_lock_init(&rttest_lock);

	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
	rt_mutex_init(&mutexes[i]);

	ret = sysdev_class_register(&rttest_sysclass);
	if (ret)
	return ret;

	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
	ret = init_test_thread(i);
	if (ret)
	break;
	ret = sysdev_create_file(&thread_data[i].sysdev, &attr_status);
	if (ret)
	break;
	ret = sysdev_create_file(&thread_data[i].sysdev, &attr_command);
	if (ret)
	break;
	}

	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );

	return ret;
	}

	device_initcall(init_rttest);