lib/test_rhashtable.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
  * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 /**************************************************************************
  * Self Test
  **************************************************************************/

 #include <linux/init.h>
 #include <linux/jhash.h>
 #include <linux/kernel.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/rcupdate.h>
 #include <linux/rhashtable.h>
 #include <linux/semaphore.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/vmalloc.h>

 #define MAX_ENTRIES	1000000
 #define TEST_INSERT_FAIL INT_MAX

 static int entries = 50000;
 module_param(entries, int, 0);
 MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)");

 static int runs = 4;
 module_param(runs, int, 0);
 MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");

 static int max_size = 0;
 module_param(max_size, int, 0);
 MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");

 static bool shrinking = false;
 module_param(shrinking, bool, 0);
 MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");

 static int size = 8;
 module_param(size, int, 0);
 MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");

 static int tcount = 10;
 module_param(tcount, int, 0);
 MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");

 static bool enomem_retry = false;
 module_param(enomem_retry, bool, 0);
 MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");

 struct test_obj_val {
 	int	id;
 	int	tid;
 };

 struct test_obj {
 	struct test_obj_val	value;
 	struct rhash_head	node;
 };

 struct thread_data {
 	int id;
 	struct task_struct *task;
 	struct test_obj *objs;
 };

 static struct test_obj array[MAX_ENTRIES];

 static struct rhashtable_params test_rht_params = {
 	.head_offset = offsetof(struct test_obj, node),
 	.key_offset = offsetof(struct test_obj, value),
 	.key_len = sizeof(struct test_obj_val),
 	.hashfn = jhash,
 	.nulls_base = (3U << RHT_BASE_SHIFT),
 };

 static struct semaphore prestart_sem;
 static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);

 static int insert_retry(struct rhashtable *ht, struct rhash_head *obj,
                         const struct rhashtable_params params)
 {
 	int err, retries = -1, enomem_retries = 0;

 	do {
 		retries++;
 		cond_resched();
 		err = rhashtable_insert_fast(ht, obj, params);
 		if (err == -ENOMEM && enomem_retry) {
 			enomem_retries++;
 			err = -EBUSY;
 		}
 	} while (err == -EBUSY);

 	if (enomem_retries)
 		pr_info(" %u insertions retried after -ENOMEM\n",
 			enomem_retries);

 	return err ? : retries;
 }

 static int __init test_rht_lookup(struct rhashtable *ht)
 {
 	unsigned int i;

 	for (i = 0; i < entries * 2; i++) {
 		struct test_obj *obj;
 		bool expected = !(i % 2);
 		struct test_obj_val key = {
 			.id = i,
 		};

 		if (array[i / 2].value.id == TEST_INSERT_FAIL)
 			expected = false;

 		obj = rhashtable_lookup_fast(ht, &key, test_rht_params);

 		if (expected && !obj) {
 			pr_warn("Test failed: Could not find key %u\n", key.id);
 			return -ENOENT;
 		} else if (!expected && obj) {
 			pr_warn("Test failed: Unexpected entry found for key %u\n",
 				key.id);
 			return -EEXIST;
 		} else if (expected && obj) {
 			if (obj->value.id != i) {
 				pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 					obj->value.id, i);
 				return -EINVAL;
 			}
 		}

 		cond_resched_rcu();
 	}

 	return 0;
 }

 static void test_bucket_stats(struct rhashtable *ht)
 {
 	unsigned int err, total = 0, chain_len = 0;
 	struct rhashtable_iter hti;
 	struct rhash_head *pos;

 	err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
 	if (err) {
 		pr_warn("Test failed: allocation error");
 		return;
 	}

 	err = rhashtable_walk_start(&hti);
 	if (err && err != -EAGAIN) {
 		pr_warn("Test failed: iterator failed: %d\n", err);
 		return;
 	}

 	while ((pos = rhashtable_walk_next(&hti))) {
 		if (PTR_ERR(pos) == -EAGAIN) {
 			pr_info("Info: encountered resize\n");
 			chain_len++;
 			continue;
 		} else if (IS_ERR(pos)) {
 			pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 				PTR_ERR(pos));
 			break;
 		}

 		total++;
 	}

 	rhashtable_walk_stop(&hti);
 	rhashtable_walk_exit(&hti);

 	pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 		total, atomic_read(&ht->nelems), entries, chain_len);

 	if (total != atomic_read(&ht->nelems) || total != entries)
 		pr_warn("Test failed: Total count mismatch ^^^");
 }

 static s64 __init test_rhashtable(struct rhashtable *ht)
 {
 	struct test_obj *obj;
 	int err;
 	unsigned int i, insert_retries = 0;
 	s64 start, end;

 	/*
 	 * Insertion Test:
 	 * Insert entries into table with all keys even numbers
 	 */
 	pr_info("  Adding %d keys\n", entries);
 	start = ktime_get_ns();
 	for (i = 0; i < entries; i++) {
 		struct test_obj *obj = &array[i];

 		obj->value.id = i * 2;
 		err = insert_retry(ht, &obj->node, test_rht_params);
 		if (err > 0)
 			insert_retries += err;
 		else if (err)
 			return err;
 	}

 	if (insert_retries)
 		pr_info("  %u insertions retried due to memory pressure\n",
 			insert_retries);

 	test_bucket_stats(ht);
 	rcu_read_lock();
 	test_rht_lookup(ht);
 	rcu_read_unlock();

 	test_bucket_stats(ht);

 	pr_info("  Deleting %d keys\n", entries);
 	for (i = 0; i < entries; i++) {
 		struct test_obj_val key = {
 			.id = i * 2,
 		};

 		if (array[i].value.id != TEST_INSERT_FAIL) {
 			obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 			BUG_ON(!obj);

 			rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 		}

 		cond_resched();
 	}

 	end = ktime_get_ns();
 	pr_info("  Duration of test: %lld ns\n", end - start);

 	return end - start;
 }

 static struct rhashtable ht;

 static int thread_lookup_test(struct thread_data *tdata)
 {
 	int i, err = 0;

 	for (i = 0; i < entries; i++) {
 		struct test_obj *obj;
 		struct test_obj_val key = {
 			.id = i,
 			.tid = tdata->id,
 		};

 		obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 		if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
 			pr_err("  found unexpected object %d-%d\n", key.tid, key.id);
 			err++;
 		} else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
 			pr_err("  object %d-%d not found!\n", key.tid, key.id);
 			err++;
 		} else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
 			pr_err("  wrong object returned (got %d-%d, expected %d-%d)\n",
 			       obj->value.tid, obj->value.id, key.tid, key.id);
 			err++;
 		}

 		cond_resched();
 	}
 	return err;
 }

 static int threadfunc(void *data)
 {
 	int i, step, err = 0, insert_retries = 0;
 	struct thread_data *tdata = data;

 	up(&prestart_sem);
 	if (down_interruptible(&startup_sem))
 		pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);

 	for (i = 0; i < entries; i++) {
 		tdata->objs[i].value.id = i;
 		tdata->objs[i].value.tid = tdata->id;
 		err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
 		if (err > 0) {
 			insert_retries += err;
 		} else if (err) {
 			pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 			       tdata->id);
 			goto out;
 		}
 	}
 	if (insert_retries)
 		pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
 			tdata->id, insert_retries);

 	err = thread_lookup_test(tdata);
 	if (err) {
 		pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 		       tdata->id);
 		goto out;
 	}

 	for (step = 10; step > 0; step--) {
 		for (i = 0; i < entries; i += step) {
 			if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
 				continue;
 			err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 			                             test_rht_params);
 			if (err) {
 				pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 				       tdata->id);
 				goto out;
 			}
 			tdata->objs[i].value.id = TEST_INSERT_FAIL;

 			cond_resched();
 		}
 		err = thread_lookup_test(tdata);
 		if (err) {
 			pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 			       tdata->id);
 			goto out;
 		}
 	}
 out:
 	while (!kthread_should_stop()) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule();
 	}
 	return err;
 }

 static int __init test_rht_init(void)
 {
 	int i, err, started_threads = 0, failed_threads = 0;
 	u64 total_time = 0;
 	struct thread_data *tdata;
 	struct test_obj *objs;

 	entries = min(entries, MAX_ENTRIES);

 	test_rht_params.automatic_shrinking = shrinking;
 	test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
 	test_rht_params.nelem_hint = size;

 	pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 		size, max_size, shrinking);

 	for (i = 0; i < runs; i++) {
 		s64 time;

 		pr_info("Test %02d:\n", i);
 		memset(&array, 0, sizeof(array));
 		err = rhashtable_init(&ht, &test_rht_params);
 		if (err < 0) {
 			pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 				err);
 			continue;
 		}

 		time = test_rhashtable(&ht);
 		rhashtable_destroy(&ht);
 		if (time < 0) {
 			pr_warn("Test failed: return code %lld\n", time);
 			return -EINVAL;
 		}

 		total_time += time;
 	}

 	do_div(total_time, runs);
 	pr_info("Average test time: %llu\n", total_time);

 	if (!tcount)
 		return 0;

 	pr_info("Testing concurrent rhashtable access from %d threads\n",
 	        tcount);
 	sema_init(&prestart_sem, 1 - tcount);
 	tdata = vzalloc(tcount * sizeof(struct thread_data));
 	if (!tdata)
 		return -ENOMEM;
 	objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 	if (!objs) {
 		vfree(tdata);
 		return -ENOMEM;
 	}

 	test_rht_params.max_size = max_size ? :
 	                           roundup_pow_of_two(tcount * entries);
 	err = rhashtable_init(&ht, &test_rht_params);
 	if (err < 0) {
 		pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 			err);
 		vfree(tdata);
 		vfree(objs);
 		return -EINVAL;
 	}
 	for (i = 0; i < tcount; i++) {
 		tdata[i].id = i;
 		tdata[i].objs = objs + i * entries;
 		tdata[i].task = kthread_run(threadfunc, &tdata[i],
 		                            "rhashtable_thrad[%d]", i);
 		if (IS_ERR(tdata[i].task))
 			pr_err(" kthread_run failed for thread %d\n", i);
 		else
 			started_threads++;
 	}
 	if (down_interruptible(&prestart_sem))
 		pr_err("  down interruptible failed\n");
 	for (i = 0; i < tcount; i++)
 		up(&startup_sem);
 	for (i = 0; i < tcount; i++) {
 		if (IS_ERR(tdata[i].task))
 			continue;
 		if ((err = kthread_stop(tdata[i].task))) {
 			pr_warn("Test failed: thread %d returned: %d\n",
 			        i, err);
 			failed_threads++;
 		}
 	}
 	pr_info("Started %d threads, %d failed\n",
 	        started_threads, failed_threads);
 	rhashtable_destroy(&ht);
 	vfree(tdata);
 	vfree(objs);
 	return 0;
 }

 static void __exit test_rht_exit(void)
 {
 }

 module_init(test_rht_init);
 module_exit(test_rht_exit);

 MODULE_LICENSE("GPL v2");
	/*
	* Resizable, Scalable, Concurrent Hash Table
	*
	* Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
	* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	/**************************************************************************
	* Self Test
	**************************************************************************/

	#include <linux/init.h>
	#include <linux/jhash.h>
	#include <linux/kernel.h>
	#include <linux/kthread.h>
	#include <linux/module.h>
	#include <linux/rcupdate.h>
	#include <linux/rhashtable.h>
	#include <linux/semaphore.h>
	#include <linux/slab.h>
	#include <linux/sched.h>
	#include <linux/vmalloc.h>

	#define MAX_ENTRIES 1000000
	#define TEST_INSERT_FAIL INT_MAX

	static int entries = 50000;
	module_param(entries, int, 0);
	MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)");

	static int runs = 4;
	module_param(runs, int, 0);
	MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");

	static int max_size = 0;
	module_param(max_size, int, 0);
	MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");

	static bool shrinking = false;
	module_param(shrinking, bool, 0);
	MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");

	static int size = 8;
	module_param(size, int, 0);
	MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");

	static int tcount = 10;
	module_param(tcount, int, 0);
	MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");

	static bool enomem_retry = false;
	module_param(enomem_retry, bool, 0);
	MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");

	struct test_obj_val {
	int id;
	int tid;
	};

	struct test_obj {
	struct test_obj_val value;
	struct rhash_head node;
	};

	struct thread_data {
	int id;
	struct task_struct *task;
	struct test_obj *objs;
	};

	static struct test_obj array[MAX_ENTRIES];

	static struct rhashtable_params test_rht_params = {
	.head_offset = offsetof(struct test_obj, node),
	.key_offset = offsetof(struct test_obj, value),
	.key_len = sizeof(struct test_obj_val),
	.hashfn = jhash,
	.nulls_base = (3U << RHT_BASE_SHIFT),
	};

	static struct semaphore prestart_sem;
	static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);

	static int insert_retry(struct rhashtable ht, struct rhash_head obj,
	const struct rhashtable_params params)
	{
	int err, retries = -1, enomem_retries = 0;

	do {
	retries++;
	cond_resched();
	err = rhashtable_insert_fast(ht, obj, params);
	if (err == -ENOMEM && enomem_retry) {
	enomem_retries++;
	err = -EBUSY;
	}
	} while (err == -EBUSY);

	if (enomem_retries)
	pr_info(" %u insertions retried after -ENOMEM\n",
	enomem_retries);

	return err ? : retries;
	}

	static int __init test_rht_lookup(struct rhashtable *ht)
	{
	unsigned int i;

	for (i = 0; i < entries * 2; i++) {
	struct test_obj *obj;
	bool expected = !(i % 2);
	struct test_obj_val key = {
	.id = i,
	};

	if (array[i / 2].value.id == TEST_INSERT_FAIL)
	expected = false;

	obj = rhashtable_lookup_fast(ht, &key, test_rht_params);

	if (expected && !obj) {
	pr_warn("Test failed: Could not find key %u\n", key.id);
	return -ENOENT;
	} else if (!expected && obj) {
	pr_warn("Test failed: Unexpected entry found for key %u\n",
	key.id);
	return -EEXIST;
	} else if (expected && obj) {
	if (obj->value.id != i) {
	pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
	obj->value.id, i);
	return -EINVAL;
	}
	}

	cond_resched_rcu();
	}

	return 0;
	}

	static void test_bucket_stats(struct rhashtable *ht)
	{
	unsigned int err, total = 0, chain_len = 0;
	struct rhashtable_iter hti;
	struct rhash_head *pos;

	err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
	if (err) {
	pr_warn("Test failed: allocation error");
	return;
	}

	err = rhashtable_walk_start(&hti);
	if (err && err != -EAGAIN) {
	pr_warn("Test failed: iterator failed: %d\n", err);
	return;
	}

	while ((pos = rhashtable_walk_next(&hti))) {
	if (PTR_ERR(pos) == -EAGAIN) {
	pr_info("Info: encountered resize\n");
	chain_len++;
	continue;
	} else if (IS_ERR(pos)) {
	pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
	PTR_ERR(pos));
	break;
	}

	total++;
	}

	rhashtable_walk_stop(&hti);
	rhashtable_walk_exit(&hti);

	pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
	total, atomic_read(&ht->nelems), entries, chain_len);

	if (total != atomic_read(&ht->nelems) \|\| total != entries)
	pr_warn("Test failed: Total count mismatch ^^^");
	}

	static s64 __init test_rhashtable(struct rhashtable *ht)
	{
	struct test_obj *obj;
	int err;
	unsigned int i, insert_retries = 0;
	s64 start, end;

	/*
	* Insertion Test:
	* Insert entries into table with all keys even numbers
	*/
	pr_info(" Adding %d keys\n", entries);
	start = ktime_get_ns();
	for (i = 0; i < entries; i++) {
	struct test_obj *obj = &array[i];

	obj->value.id = i * 2;
	err = insert_retry(ht, &obj->node, test_rht_params);
	if (err > 0)
	insert_retries += err;
	else if (err)
	return err;
	}

	if (insert_retries)
	pr_info(" %u insertions retried due to memory pressure\n",
	insert_retries);

	test_bucket_stats(ht);
	rcu_read_lock();
	test_rht_lookup(ht);
	rcu_read_unlock();

	test_bucket_stats(ht);

	pr_info(" Deleting %d keys\n", entries);
	for (i = 0; i < entries; i++) {
	struct test_obj_val key = {
	.id = i * 2,
	};

	if (array[i].value.id != TEST_INSERT_FAIL) {
	obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
	BUG_ON(!obj);

	rhashtable_remove_fast(ht, &obj->node, test_rht_params);
	}

	cond_resched();
	}

	end = ktime_get_ns();
	pr_info(" Duration of test: %lld ns\n", end - start);

	return end - start;
	}

	static struct rhashtable ht;

	static int thread_lookup_test(struct thread_data *tdata)
	{
	int i, err = 0;

	for (i = 0; i < entries; i++) {
	struct test_obj *obj;
	struct test_obj_val key = {
	.id = i,
	.tid = tdata->id,
	};

	obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
	if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
	pr_err(" found unexpected object %d-%d\n", key.tid, key.id);
	err++;
	} else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
	pr_err(" object %d-%d not found!\n", key.tid, key.id);
	err++;
	} else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
	pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
	obj->value.tid, obj->value.id, key.tid, key.id);
	err++;
	}

	cond_resched();
	}
	return err;
	}

	static int threadfunc(void *data)
	{
	int i, step, err = 0, insert_retries = 0;
	struct thread_data *tdata = data;

	up(&prestart_sem);
	if (down_interruptible(&startup_sem))
	pr_err(" thread[%d]: down_interruptible failed\n", tdata->id);

	for (i = 0; i < entries; i++) {
	tdata->objs[i].value.id = i;
	tdata->objs[i].value.tid = tdata->id;
	err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
	if (err > 0) {
	insert_retries += err;
	} else if (err) {
	pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
	tdata->id);
	goto out;
	}
	}
	if (insert_retries)
	pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
	tdata->id, insert_retries);

	err = thread_lookup_test(tdata);
	if (err) {
	pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
	tdata->id);
	goto out;
	}

	for (step = 10; step > 0; step--) {
	for (i = 0; i < entries; i += step) {
	if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
	continue;
	err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
	test_rht_params);
	if (err) {
	pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
	tdata->id);
	goto out;
	}
	tdata->objs[i].value.id = TEST_INSERT_FAIL;

	cond_resched();
	}
	err = thread_lookup_test(tdata);
	if (err) {
	pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
	tdata->id);
	goto out;
	}
	}
	out:
	while (!kthread_should_stop()) {
	set_current_state(TASK_INTERRUPTIBLE);
	schedule();
	}
	return err;
	}

	static int __init test_rht_init(void)
	{
	int i, err, started_threads = 0, failed_threads = 0;
	u64 total_time = 0;
	struct thread_data *tdata;
	struct test_obj *objs;

	entries = min(entries, MAX_ENTRIES);

	test_rht_params.automatic_shrinking = shrinking;
	test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
	test_rht_params.nelem_hint = size;

	pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
	size, max_size, shrinking);

	for (i = 0; i < runs; i++) {
	s64 time;

	pr_info("Test %02d:\n", i);
	memset(&array, 0, sizeof(array));
	err = rhashtable_init(&ht, &test_rht_params);
	if (err < 0) {
	pr_warn("Test failed: Unable to initialize hashtable: %d\n",
	err);
	continue;
	}

	time = test_rhashtable(&ht);
	rhashtable_destroy(&ht);
	if (time < 0) {
	pr_warn("Test failed: return code %lld\n", time);
	return -EINVAL;
	}

	total_time += time;
	}

	do_div(total_time, runs);
	pr_info("Average test time: %llu\n", total_time);

	if (!tcount)
	return 0;

	pr_info("Testing concurrent rhashtable access from %d threads\n",
	tcount);
	sema_init(&prestart_sem, 1 - tcount);
	tdata = vzalloc(tcount * sizeof(struct thread_data));
	if (!tdata)
	return -ENOMEM;
	objs = vzalloc(tcount * entries * sizeof(struct test_obj));
	if (!objs) {
	vfree(tdata);
	return -ENOMEM;
	}

	test_rht_params.max_size = max_size ? :
	roundup_pow_of_two(tcount * entries);
	err = rhashtable_init(&ht, &test_rht_params);
	if (err < 0) {
	pr_warn("Test failed: Unable to initialize hashtable: %d\n",
	err);
	vfree(tdata);
	vfree(objs);
	return -EINVAL;
	}
	for (i = 0; i < tcount; i++) {
	tdata[i].id = i;
	tdata[i].objs = objs + i * entries;
	tdata[i].task = kthread_run(threadfunc, &tdata[i],
	"rhashtable_thrad[%d]", i);
	if (IS_ERR(tdata[i].task))
	pr_err(" kthread_run failed for thread %d\n", i);
	else
	started_threads++;
	}
	if (down_interruptible(&prestart_sem))
	pr_err(" down interruptible failed\n");
	for (i = 0; i < tcount; i++)
	up(&startup_sem);
	for (i = 0; i < tcount; i++) {
	if (IS_ERR(tdata[i].task))
	continue;
	if ((err = kthread_stop(tdata[i].task))) {
	pr_warn("Test failed: thread %d returned: %d\n",
	i, err);
	failed_threads++;
	}
	}
	pr_info("Started %d threads, %d failed\n",
	started_threads, failed_threads);
	rhashtable_destroy(&ht);
	vfree(tdata);
	vfree(objs);
	return 0;
	}

	static void __exit test_rht_exit(void)
	{
	}

	module_init(test_rht_init);
	module_exit(test_rht_exit);

	MODULE_LICENSE("GPL v2");