kernel/locking/test-ww_mutex.c - arm/linux - Git at Google

 /*
  * Module-based API test facility for ww_mutexes
  *
  * 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, you can access it online at
  * http://www.gnu.org/licenses/gpl-2.0.html.
  */

 #include <linux/kernel.h>

 #include <linux/completion.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/ww_mutex.h>

 static DEFINE_WW_CLASS(ww_class);
 struct workqueue_struct *wq;

 struct test_mutex {
 	struct work_struct work;
 	struct ww_mutex mutex;
 	struct completion ready, go, done;
 	unsigned int flags;
 };

 #define TEST_MTX_SPIN BIT(0)
 #define TEST_MTX_TRY BIT(1)
 #define TEST_MTX_CTX BIT(2)
 #define __TEST_MTX_LAST BIT(3)

 static void test_mutex_work(struct work_struct *work)
 {
 	struct test_mutex *mtx = container_of(work, typeof(*mtx), work);

 	complete(&mtx->ready);
 	wait_for_completion(&mtx->go);

 	if (mtx->flags & TEST_MTX_TRY) {
 		while (!ww_mutex_trylock(&mtx->mutex))
 			cpu_relax();
 	} else {
 		ww_mutex_lock(&mtx->mutex, NULL);
 	}
 	complete(&mtx->done);
 	ww_mutex_unlock(&mtx->mutex);
 }

 static int __test_mutex(unsigned int flags)
 {
 #define TIMEOUT (HZ / 16)
 	struct test_mutex mtx;
 	struct ww_acquire_ctx ctx;
 	int ret;

 	ww_mutex_init(&mtx.mutex, &ww_class);
 	ww_acquire_init(&ctx, &ww_class);

 	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
 	init_completion(&mtx.ready);
 	init_completion(&mtx.go);
 	init_completion(&mtx.done);
 	mtx.flags = flags;

 	schedule_work(&mtx.work);

 	wait_for_completion(&mtx.ready);
 	ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
 	complete(&mtx.go);
 	if (flags & TEST_MTX_SPIN) {
 		unsigned long timeout = jiffies + TIMEOUT;

 		ret = 0;
 		do {
 			if (completion_done(&mtx.done)) {
 				ret = -EINVAL;
 				break;
 			}
 			cpu_relax();
 		} while (time_before(jiffies, timeout));
 	} else {
 		ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
 	}
 	ww_mutex_unlock(&mtx.mutex);
 	ww_acquire_fini(&ctx);

 	if (ret) {
 		pr_err("%s(flags=%x): mutual exclusion failure\n",
 		       __func__, flags);
 		ret = -EINVAL;
 	}

 	flush_work(&mtx.work);
 	destroy_work_on_stack(&mtx.work);
 	return ret;
 #undef TIMEOUT
 }

 static int test_mutex(void)
 {
 	int ret;
 	int i;

 	for (i = 0; i < __TEST_MTX_LAST; i++) {
 		ret = __test_mutex(i);
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 static int test_aa(void)
 {
 	struct ww_mutex mutex;
 	struct ww_acquire_ctx ctx;
 	int ret;

 	ww_mutex_init(&mutex, &ww_class);
 	ww_acquire_init(&ctx, &ww_class);

 	ww_mutex_lock(&mutex, &ctx);

 	if (ww_mutex_trylock(&mutex))  {
 		pr_err("%s: trylocked itself!\n", __func__);
 		ww_mutex_unlock(&mutex);
 		ret = -EINVAL;
 		goto out;
 	}

 	ret = ww_mutex_lock(&mutex, &ctx);
 	if (ret != -EALREADY) {
 		pr_err("%s: missed deadlock for recursing, ret=%d\n",
 		       __func__, ret);
 		if (!ret)
 			ww_mutex_unlock(&mutex);
 		ret = -EINVAL;
 		goto out;
 	}

 	ret = 0;
 out:
 	ww_mutex_unlock(&mutex);
 	ww_acquire_fini(&ctx);
 	return ret;
 }

 struct test_abba {
 	struct work_struct work;
 	struct ww_mutex a_mutex;
 	struct ww_mutex b_mutex;
 	struct completion a_ready;
 	struct completion b_ready;
 	bool resolve;
 	int result;
 };

 static void test_abba_work(struct work_struct *work)
 {
 	struct test_abba *abba = container_of(work, typeof(*abba), work);
 	struct ww_acquire_ctx ctx;
 	int err;

 	ww_acquire_init(&ctx, &ww_class);
 	ww_mutex_lock(&abba->b_mutex, &ctx);

 	complete(&abba->b_ready);
 	wait_for_completion(&abba->a_ready);

 	err = ww_mutex_lock(&abba->a_mutex, &ctx);
 	if (abba->resolve && err == -EDEADLK) {
 		ww_mutex_unlock(&abba->b_mutex);
 		ww_mutex_lock_slow(&abba->a_mutex, &ctx);
 		err = ww_mutex_lock(&abba->b_mutex, &ctx);
 	}

 	if (!err)
 		ww_mutex_unlock(&abba->a_mutex);
 	ww_mutex_unlock(&abba->b_mutex);
 	ww_acquire_fini(&ctx);

 	abba->result = err;
 }

 static int test_abba(bool resolve)
 {
 	struct test_abba abba;
 	struct ww_acquire_ctx ctx;
 	int err, ret;

 	ww_mutex_init(&abba.a_mutex, &ww_class);
 	ww_mutex_init(&abba.b_mutex, &ww_class);
 	INIT_WORK_ONSTACK(&abba.work, test_abba_work);
 	init_completion(&abba.a_ready);
 	init_completion(&abba.b_ready);
 	abba.resolve = resolve;

 	schedule_work(&abba.work);

 	ww_acquire_init(&ctx, &ww_class);
 	ww_mutex_lock(&abba.a_mutex, &ctx);

 	complete(&abba.a_ready);
 	wait_for_completion(&abba.b_ready);

 	err = ww_mutex_lock(&abba.b_mutex, &ctx);
 	if (resolve && err == -EDEADLK) {
 		ww_mutex_unlock(&abba.a_mutex);
 		ww_mutex_lock_slow(&abba.b_mutex, &ctx);
 		err = ww_mutex_lock(&abba.a_mutex, &ctx);
 	}

 	if (!err)
 		ww_mutex_unlock(&abba.b_mutex);
 	ww_mutex_unlock(&abba.a_mutex);
 	ww_acquire_fini(&ctx);

 	flush_work(&abba.work);
 	destroy_work_on_stack(&abba.work);

 	ret = 0;
 	if (resolve) {
 		if (err || abba.result) {
 			pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
 			       __func__, err, abba.result);
 			ret = -EINVAL;
 		}
 	} else {
 		if (err != -EDEADLK && abba.result != -EDEADLK) {
 			pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
 			       __func__, err, abba.result);
 			ret = -EINVAL;
 		}
 	}
 	return ret;
 }

 struct test_cycle {
 	struct work_struct work;
 	struct ww_mutex a_mutex;
 	struct ww_mutex *b_mutex;
 	struct completion *a_signal;
 	struct completion b_signal;
 	int result;
 };

 static void test_cycle_work(struct work_struct *work)
 {
 	struct test_cycle *cycle = container_of(work, typeof(*cycle), work);
 	struct ww_acquire_ctx ctx;
 	int err;

 	ww_acquire_init(&ctx, &ww_class);
 	ww_mutex_lock(&cycle->a_mutex, &ctx);

 	complete(cycle->a_signal);
 	wait_for_completion(&cycle->b_signal);

 	err = ww_mutex_lock(cycle->b_mutex, &ctx);
 	if (err == -EDEADLK) {
 		ww_mutex_unlock(&cycle->a_mutex);
 		ww_mutex_lock_slow(cycle->b_mutex, &ctx);
 		err = ww_mutex_lock(&cycle->a_mutex, &ctx);
 	}

 	if (!err)
 		ww_mutex_unlock(cycle->b_mutex);
 	ww_mutex_unlock(&cycle->a_mutex);
 	ww_acquire_fini(&ctx);

 	cycle->result = err;
 }

 static int __test_cycle(unsigned int nthreads)
 {
 	struct test_cycle *cycles;
 	unsigned int n, last = nthreads - 1;
 	int ret;

 	cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL);
 	if (!cycles)
 		return -ENOMEM;

 	for (n = 0; n < nthreads; n++) {
 		struct test_cycle *cycle = &cycles[n];

 		ww_mutex_init(&cycle->a_mutex, &ww_class);
 		if (n == last)
 			cycle->b_mutex = &cycles[0].a_mutex;
 		else
 			cycle->b_mutex = &cycles[n + 1].a_mutex;

 		if (n == 0)
 			cycle->a_signal = &cycles[last].b_signal;
 		else
 			cycle->a_signal = &cycles[n - 1].b_signal;
 		init_completion(&cycle->b_signal);

 		INIT_WORK(&cycle->work, test_cycle_work);
 		cycle->result = 0;
 	}

 	for (n = 0; n < nthreads; n++)
 		queue_work(wq, &cycles[n].work);

 	flush_workqueue(wq);

 	ret = 0;
 	for (n = 0; n < nthreads; n++) {
 		struct test_cycle *cycle = &cycles[n];

 		if (!cycle->result)
 			continue;

 		pr_err("cylic deadlock not resolved, ret[%d/%d] = %d\n",
 		       n, nthreads, cycle->result);
 		ret = -EINVAL;
 		break;
 	}

 	for (n = 0; n < nthreads; n++)
 		ww_mutex_destroy(&cycles[n].a_mutex);
 	kfree(cycles);
 	return ret;
 }

 static int test_cycle(unsigned int ncpus)
 {
 	unsigned int n;
 	int ret;

 	for (n = 2; n <= ncpus + 1; n++) {
 		ret = __test_cycle(n);
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 static int __init test_ww_mutex_init(void)
 {
 	int ncpus = num_online_cpus();
 	int ret;

 	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
 	if (!wq)
 		return -ENOMEM;

 	ret = test_mutex();
 	if (ret)
 		return ret;

 	ret = test_aa();
 	if (ret)
 		return ret;

 	ret = test_abba(false);
 	if (ret)
 		return ret;

 	ret = test_abba(true);
 	if (ret)
 		return ret;

 	ret = test_cycle(ncpus);
 	if (ret)
 		return ret;

 	return 0;
 }

 static void __exit test_ww_mutex_exit(void)
 {
 	destroy_workqueue(wq);
 }

 module_init(test_ww_mutex_init);
 module_exit(test_ww_mutex_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Intel Corporation");
	/*
	* Module-based API test facility for ww_mutexes
	*
	* 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, you can access it online at
	* http://www.gnu.org/licenses/gpl-2.0.html.
	*/

	#include <linux/kernel.h>

	#include <linux/completion.h>
	#include <linux/kthread.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/ww_mutex.h>

	static DEFINE_WW_CLASS(ww_class);
	struct workqueue_struct *wq;

	struct test_mutex {
	struct work_struct work;
	struct ww_mutex mutex;
	struct completion ready, go, done;
	unsigned int flags;
	};

	#define TEST_MTX_SPIN BIT(0)
	#define TEST_MTX_TRY BIT(1)
	#define TEST_MTX_CTX BIT(2)
	#define __TEST_MTX_LAST BIT(3)

	static void test_mutex_work(struct work_struct *work)
	{
	struct test_mutex mtx = container_of(work, typeof(mtx), work);

	complete(&mtx->ready);
	wait_for_completion(&mtx->go);

	if (mtx->flags & TEST_MTX_TRY) {
	while (!ww_mutex_trylock(&mtx->mutex))
	cpu_relax();
	} else {
	ww_mutex_lock(&mtx->mutex, NULL);
	}
	complete(&mtx->done);
	ww_mutex_unlock(&mtx->mutex);
	}

	static int __test_mutex(unsigned int flags)
	{
	#define TIMEOUT (HZ / 16)
	struct test_mutex mtx;
	struct ww_acquire_ctx ctx;
	int ret;

	ww_mutex_init(&mtx.mutex, &ww_class);
	ww_acquire_init(&ctx, &ww_class);

	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
	init_completion(&mtx.ready);
	init_completion(&mtx.go);
	init_completion(&mtx.done);
	mtx.flags = flags;

	schedule_work(&mtx.work);

	wait_for_completion(&mtx.ready);
	ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
	complete(&mtx.go);
	if (flags & TEST_MTX_SPIN) {
	unsigned long timeout = jiffies + TIMEOUT;

	ret = 0;
	do {
	if (completion_done(&mtx.done)) {
	ret = -EINVAL;
	break;
	}
	cpu_relax();
	} while (time_before(jiffies, timeout));
	} else {
	ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
	}
	ww_mutex_unlock(&mtx.mutex);
	ww_acquire_fini(&ctx);

	if (ret) {
	pr_err("%s(flags=%x): mutual exclusion failure\n",
	__func__, flags);
	ret = -EINVAL;
	}

	flush_work(&mtx.work);
	destroy_work_on_stack(&mtx.work);
	return ret;
	#undef TIMEOUT
	}

	static int test_mutex(void)
	{
	int ret;
	int i;

	for (i = 0; i < __TEST_MTX_LAST; i++) {
	ret = __test_mutex(i);
	if (ret)
	return ret;
	}

	return 0;
	}

	static int test_aa(void)
	{
	struct ww_mutex mutex;
	struct ww_acquire_ctx ctx;
	int ret;

	ww_mutex_init(&mutex, &ww_class);
	ww_acquire_init(&ctx, &ww_class);

	ww_mutex_lock(&mutex, &ctx);

	if (ww_mutex_trylock(&mutex)) {
	pr_err("%s: trylocked itself!\n", __func__);
	ww_mutex_unlock(&mutex);
	ret = -EINVAL;
	goto out;
	}

	ret = ww_mutex_lock(&mutex, &ctx);
	if (ret != -EALREADY) {
	pr_err("%s: missed deadlock for recursing, ret=%d\n",
	__func__, ret);
	if (!ret)
	ww_mutex_unlock(&mutex);
	ret = -EINVAL;
	goto out;
	}

	ret = 0;
	out:
	ww_mutex_unlock(&mutex);
	ww_acquire_fini(&ctx);
	return ret;
	}

	struct test_abba {
	struct work_struct work;
	struct ww_mutex a_mutex;
	struct ww_mutex b_mutex;
	struct completion a_ready;
	struct completion b_ready;
	bool resolve;
	int result;
	};

	static void test_abba_work(struct work_struct *work)
	{
	struct test_abba abba = container_of(work, typeof(abba), work);
	struct ww_acquire_ctx ctx;
	int err;

	ww_acquire_init(&ctx, &ww_class);
	ww_mutex_lock(&abba->b_mutex, &ctx);

	complete(&abba->b_ready);
	wait_for_completion(&abba->a_ready);

	err = ww_mutex_lock(&abba->a_mutex, &ctx);
	if (abba->resolve && err == -EDEADLK) {
	ww_mutex_unlock(&abba->b_mutex);
	ww_mutex_lock_slow(&abba->a_mutex, &ctx);
	err = ww_mutex_lock(&abba->b_mutex, &ctx);
	}

	if (!err)
	ww_mutex_unlock(&abba->a_mutex);
	ww_mutex_unlock(&abba->b_mutex);
	ww_acquire_fini(&ctx);

	abba->result = err;
	}

	static int test_abba(bool resolve)
	{
	struct test_abba abba;
	struct ww_acquire_ctx ctx;
	int err, ret;

	ww_mutex_init(&abba.a_mutex, &ww_class);
	ww_mutex_init(&abba.b_mutex, &ww_class);
	INIT_WORK_ONSTACK(&abba.work, test_abba_work);
	init_completion(&abba.a_ready);
	init_completion(&abba.b_ready);
	abba.resolve = resolve;

	schedule_work(&abba.work);

	ww_acquire_init(&ctx, &ww_class);
	ww_mutex_lock(&abba.a_mutex, &ctx);

	complete(&abba.a_ready);
	wait_for_completion(&abba.b_ready);

	err = ww_mutex_lock(&abba.b_mutex, &ctx);
	if (resolve && err == -EDEADLK) {
	ww_mutex_unlock(&abba.a_mutex);
	ww_mutex_lock_slow(&abba.b_mutex, &ctx);
	err = ww_mutex_lock(&abba.a_mutex, &ctx);
	}

	if (!err)
	ww_mutex_unlock(&abba.b_mutex);
	ww_mutex_unlock(&abba.a_mutex);
	ww_acquire_fini(&ctx);

	flush_work(&abba.work);
	destroy_work_on_stack(&abba.work);

	ret = 0;
	if (resolve) {
	if (err \|\| abba.result) {
	pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
	__func__, err, abba.result);
	ret = -EINVAL;
	}
	} else {
	if (err != -EDEADLK && abba.result != -EDEADLK) {
	pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
	__func__, err, abba.result);
	ret = -EINVAL;
	}
	}
	return ret;
	}

	struct test_cycle {
	struct work_struct work;
	struct ww_mutex a_mutex;
	struct ww_mutex *b_mutex;
	struct completion *a_signal;
	struct completion b_signal;
	int result;
	};

	static void test_cycle_work(struct work_struct *work)
	{
	struct test_cycle cycle = container_of(work, typeof(cycle), work);
	struct ww_acquire_ctx ctx;
	int err;

	ww_acquire_init(&ctx, &ww_class);
	ww_mutex_lock(&cycle->a_mutex, &ctx);

	complete(cycle->a_signal);
	wait_for_completion(&cycle->b_signal);

	err = ww_mutex_lock(cycle->b_mutex, &ctx);
	if (err == -EDEADLK) {
	ww_mutex_unlock(&cycle->a_mutex);
	ww_mutex_lock_slow(cycle->b_mutex, &ctx);
	err = ww_mutex_lock(&cycle->a_mutex, &ctx);
	}

	if (!err)
	ww_mutex_unlock(cycle->b_mutex);
	ww_mutex_unlock(&cycle->a_mutex);
	ww_acquire_fini(&ctx);

	cycle->result = err;
	}

	static int __test_cycle(unsigned int nthreads)
	{
	struct test_cycle *cycles;
	unsigned int n, last = nthreads - 1;
	int ret;

	cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL);
	if (!cycles)
	return -ENOMEM;

	for (n = 0; n < nthreads; n++) {
	struct test_cycle *cycle = &cycles[n];

	ww_mutex_init(&cycle->a_mutex, &ww_class);
	if (n == last)
	cycle->b_mutex = &cycles[0].a_mutex;
	else
	cycle->b_mutex = &cycles[n + 1].a_mutex;

	if (n == 0)
	cycle->a_signal = &cycles[last].b_signal;
	else
	cycle->a_signal = &cycles[n - 1].b_signal;
	init_completion(&cycle->b_signal);

	INIT_WORK(&cycle->work, test_cycle_work);
	cycle->result = 0;
	}

	for (n = 0; n < nthreads; n++)
	queue_work(wq, &cycles[n].work);

	flush_workqueue(wq);

	ret = 0;
	for (n = 0; n < nthreads; n++) {
	struct test_cycle *cycle = &cycles[n];

	if (!cycle->result)
	continue;

	pr_err("cylic deadlock not resolved, ret[%d/%d] = %d\n",
	n, nthreads, cycle->result);
	ret = -EINVAL;
	break;
	}

	for (n = 0; n < nthreads; n++)
	ww_mutex_destroy(&cycles[n].a_mutex);
	kfree(cycles);
	return ret;
	}

	static int test_cycle(unsigned int ncpus)
	{
	unsigned int n;
	int ret;

	for (n = 2; n <= ncpus + 1; n++) {
	ret = __test_cycle(n);
	if (ret)
	return ret;
	}

	return 0;
	}

	static int __init test_ww_mutex_init(void)
	{
	int ncpus = num_online_cpus();
	int ret;

	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
	if (!wq)
	return -ENOMEM;

	ret = test_mutex();
	if (ret)
	return ret;

	ret = test_aa();
	if (ret)
	return ret;

	ret = test_abba(false);
	if (ret)
	return ret;

	ret = test_abba(true);
	if (ret)
	return ret;

	ret = test_cycle(ncpus);
	if (ret)
	return ret;

	return 0;
	}

	static void __exit test_ww_mutex_exit(void)
	{
	destroy_workqueue(wq);
	}

	module_init(test_ww_mutex_init);
	module_exit(test_ww_mutex_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Intel Corporation");