rtmutex: Delete scriptable tester

No one uses this anymore, and this is not the first time the
idea of replacing it with a (now possible) userspace side.
Lock stealing logic was removed long ago in when the lock
was granted to the highest prio.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1435782588-4177-2-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 1 insertions, 444 deletions

diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 7dd5c9918e4c..36942047ffc0 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -20,7 +20,6 @@ obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
-obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
diff --git a/kernel/locking/rtmutex-tester.c b/kernel/locking/rtmutex-tester.c
deleted file mode 100644
index 1d96dd0d93c1..000000000000
--- a/kernel/locking/rtmutex-tester.c
+++ /dev/null
@@ -1,420 +0,0 @@
-/*
- * RT-Mutex-tester: scriptable tester for rt mutexes
- *
- * started by Thomas Gleixner:
- *
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- */
-#include <linux/device.h>
-#include <linux/kthread.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/spinlock.h>
-#include <linux/timer.h>
-#include <linux/freezer.h>
-#include <linux/stat.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			event;
-	struct device		dev;
-};
-
-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 */
-	/* 9, 10 - reserved for BKL commemoration */
-	RTTEST_SIGNAL = 11,	/* 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;
-			}
-		}
-		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;
-
-	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;
-
-	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;
-
-	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 device *dev, struct device_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, dev);
-	tid = td->dev.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 device *dev, struct device_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, dev);
-	tsk = threads[td->dev.id];
-
-	spin_lock(&rttest_lock);
-
-	curr += sprintf(curr,
-		"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",
-		td->opcode, td->event, tsk->state,
-			(MAX_RT_PRIO - 1) - tsk->prio,
-			(MAX_RT_PRIO - 1) - tsk->normal_prio,
-		tsk->pi_blocked_on);
-
-	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->dev.id].owner);
-
-	return curr - buf;
-}
-
-static DEVICE_ATTR(status, S_IRUSR, sysfs_test_status, NULL);
-static DEVICE_ATTR(command, S_IWUSR, NULL, sysfs_test_command);
-
-static struct bus_type rttest_subsys = {
-	.name = "rttest",
-	.dev_name = "rttest",
-};
-
-static int init_test_thread(int id)
-{
-	thread_data[id].dev.bus = &rttest_subsys;
-	thread_data[id].dev.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 device_register(&thread_data[id].dev);
-}
-
-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 = subsys_system_register(&rttest_subsys, NULL);
-	if (ret)
-		return ret;
-
-	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
-		ret = init_test_thread(i);
-		if (ret)
-			break;
-		ret = device_create_file(&thread_data[i].dev, &dev_attr_status);
-		if (ret)
-			break;
-		ret = device_create_file(&thread_data[i].dev, &dev_attr_command);
-		if (ret)
-			break;
-	}
-
-	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
-
-	return ret;
-}
-
-device_initcall(init_rttest);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 5674b073473c..7781d801212f 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1120,7 +1120,7 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 
 		debug_rt_mutex_print_deadlock(waiter);
 
-		schedule_rt_mutex(lock);
+		schedule();
 
 		raw_spin_lock(&lock->wait_lock);
 		set_current_state(state);
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 7844f8f0e639..4f5f83c7d2d3 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -15,28 +15,6 @@
 #include <linux/rtmutex.h>
 
 /*
- * The rtmutex in kernel tester is independent of rtmutex debugging. We
- * call schedule_rt_mutex_test() instead of schedule() for the tasks which
- * belong to the tester. That way we can delay the wakeup path of those
- * threads to provoke lock stealing and testing of  complex boosting scenarios.
- */
-#ifdef CONFIG_RT_MUTEX_TESTER
-
-extern void schedule_rt_mutex_test(struct rt_mutex *lock);
-
-#define schedule_rt_mutex(_lock)				\
-  do {								\
-	if (!(current->flags & PF_MUTEX_TESTER))		\
-		schedule();					\
-	else							\
-		schedule_rt_mutex_test(_lock);			\
-  } while (0)
-
-#else
-# define schedule_rt_mutex(_lock)			schedule()
-#endif
-
-/*
  * This is the control structure for tasks blocked on a rt_mutex,
  * which is allocated on the kernel stack on of the blocked task.
  *