1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Resizable, Scalable, Concurrent Hash Table
  4 *
  5 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
  6 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  7 */
  8
  9/**************************************************************************
 10 * Self Test
 11 **************************************************************************/
 12
 13#include <linux/init.h>
 14#include <linux/jhash.h>
 15#include <linux/kernel.h>
 16#include <linux/kthread.h>
 17#include <linux/module.h>
 18#include <linux/rcupdate.h>
 19#include <linux/rhashtable.h>
 20#include <linux/slab.h>
 21#include <linux/sched.h>
 22#include <linux/random.h>
 23#include <linux/vmalloc.h>
 24#include <linux/wait.h>
 25
 26#define MAX_ENTRIES	1000000
 27#define TEST_INSERT_FAIL INT_MAX
 28
 29static int parm_entries = 50000;
 30module_param(parm_entries, int, 0);
 31MODULE_PARM_DESC(parm_entries, "Number of entries to add (default: 50000)");
 32
 33static int runs = 4;
 34module_param(runs, int, 0);
 35MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
 36
 37static int max_size = 0;
 38module_param(max_size, int, 0);
 39MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
 40
 41static bool shrinking = false;
 42module_param(shrinking, bool, 0);
 43MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
 44
 45static int size = 8;
 46module_param(size, int, 0);
 47MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
 48
 49static int tcount = 10;
 50module_param(tcount, int, 0);
 51MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
 52
 53static bool enomem_retry = false;
 54module_param(enomem_retry, bool, 0);
 55MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
 56
 57struct test_obj_val {
 58	int	id;
 59	int	tid;
 60};
 61
 62struct test_obj {
 63	struct test_obj_val	value;
 64	struct rhash_head	node;
 65};
 66
 67struct test_obj_rhl {
 68	struct test_obj_val	value;
 69	struct rhlist_head	list_node;
 70};
 71
 72struct thread_data {
 73	unsigned int entries;
 74	int id;
 75	struct task_struct *task;
 76	struct test_obj *objs;
 77};
 78
 79static u32 my_hashfn(const void *data, u32 len, u32 seed)
 80{
 81	const struct test_obj_rhl *obj = data;
 82
 83	return (obj->value.id % 10);
 84}
 85
 86static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
 87{
 88	const struct test_obj_rhl *test_obj = obj;
 89	const struct test_obj_val *val = arg->key;
 90
 91	return test_obj->value.id - val->id;
 92}
 93
 94static struct rhashtable_params test_rht_params = {
 95	.head_offset = offsetof(struct test_obj, node),
 96	.key_offset = offsetof(struct test_obj, value),
 97	.key_len = sizeof(struct test_obj_val),
 98	.hashfn = jhash,
 99};
100
101static struct rhashtable_params test_rht_params_dup = {
102	.head_offset = offsetof(struct test_obj_rhl, list_node),
103	.key_offset = offsetof(struct test_obj_rhl, value),
104	.key_len = sizeof(struct test_obj_val),
105	.hashfn = jhash,
106	.obj_hashfn = my_hashfn,
107	.obj_cmpfn = my_cmpfn,
108	.nelem_hint = 128,
109	.automatic_shrinking = false,
110};
111
112static atomic_t startup_count;
113static DECLARE_WAIT_QUEUE_HEAD(startup_wait);
114
115static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
116                        const struct rhashtable_params params)
117{
118	int err, retries = -1, enomem_retries = 0;
119
120	do {
121		retries++;
122		cond_resched();
123		err = rhashtable_insert_fast(ht, &obj->node, params);
124		if (err == -ENOMEM && enomem_retry) {
125			enomem_retries++;
126			err = -EBUSY;
127		}
128	} while (err == -EBUSY);
129
130	if (enomem_retries)
131		pr_info(" %u insertions retried after -ENOMEM\n",
132			enomem_retries);
133
134	return err ? : retries;
135}
136
137static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
138				  unsigned int entries)
139{
140	unsigned int i;
141
142	for (i = 0; i < entries; i++) {
143		struct test_obj *obj;
144		bool expected = !(i % 2);
145		struct test_obj_val key = {
146			.id = i,
147		};
148
149		if (array[i / 2].value.id == TEST_INSERT_FAIL)
150			expected = false;
151
152		obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
153
154		if (expected && !obj) {
155			pr_warn("Test failed: Could not find key %u\n", key.id);
156			return -ENOENT;
157		} else if (!expected && obj) {
158			pr_warn("Test failed: Unexpected entry found for key %u\n",
159				key.id);
160			return -EEXIST;
161		} else if (expected && obj) {
162			if (obj->value.id != i) {
163				pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
164					obj->value.id, i);
165				return -EINVAL;
166			}
167		}
168
169		cond_resched_rcu();
170	}
171
172	return 0;
173}
174
175static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
176{
177	unsigned int total = 0, chain_len = 0;
178	struct rhashtable_iter hti;
179	struct rhash_head *pos;
180
181	rhashtable_walk_enter(ht, &hti);
182	rhashtable_walk_start(&hti);
183
184	while ((pos = rhashtable_walk_next(&hti))) {
185		if (PTR_ERR(pos) == -EAGAIN) {
186			pr_info("Info: encountered resize\n");
187			chain_len++;
188			continue;
189		} else if (IS_ERR(pos)) {
190			pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
191				PTR_ERR(pos));
192			break;
193		}
194
195		total++;
196	}
197
198	rhashtable_walk_stop(&hti);
199	rhashtable_walk_exit(&hti);
200
201	pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
202		total, atomic_read(&ht->nelems), entries, chain_len);
203
204	if (total != atomic_read(&ht->nelems) || total != entries)
205		pr_warn("Test failed: Total count mismatch ^^^");
206}
207
208static s64 __init test_rhashtable(struct rhashtable *ht, struct test_obj *array,
209				  unsigned int entries)
210{
211	struct test_obj *obj;
212	int err;
213	unsigned int i, insert_retries = 0;
214	s64 start, end;
215
216	/*
217	 * Insertion Test:
218	 * Insert entries into table with all keys even numbers
219	 */
220	pr_info("  Adding %d keys\n", entries);
221	start = ktime_get_ns();
222	for (i = 0; i < entries; i++) {
223		struct test_obj *obj = &array[i];
224
225		obj->value.id = i * 2;
226		err = insert_retry(ht, obj, test_rht_params);
227		if (err > 0)
228			insert_retries += err;
229		else if (err)
230			return err;
231	}
232
233	if (insert_retries)
234		pr_info("  %u insertions retried due to memory pressure\n",
235			insert_retries);
236
237	test_bucket_stats(ht, entries);
238	rcu_read_lock();
239	test_rht_lookup(ht, array, entries);
240	rcu_read_unlock();
241
242	test_bucket_stats(ht, entries);
243
244	pr_info("  Deleting %d keys\n", entries);
245	for (i = 0; i < entries; i++) {
246		struct test_obj_val key = {
247			.id = i * 2,
248		};
249
250		if (array[i].value.id != TEST_INSERT_FAIL) {
251			obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
252			BUG_ON(!obj);
253
254			rhashtable_remove_fast(ht, &obj->node, test_rht_params);
255		}
256
257		cond_resched();
258	}
259
260	end = ktime_get_ns();
261	pr_info("  Duration of test: %lld ns\n", end - start);
262
263	return end - start;
264}
265
266static struct rhashtable ht;
267static struct rhltable rhlt;
268
269static int __init test_rhltable(unsigned int entries)
270{
271	struct test_obj_rhl *rhl_test_objects;
272	unsigned long *obj_in_table;
273	unsigned int i, j, k;
274	int ret, err;
275
276	if (entries == 0)
277		entries = 1;
278
279	rhl_test_objects = vzalloc(array_size(entries,
280					      sizeof(*rhl_test_objects)));
281	if (!rhl_test_objects)
282		return -ENOMEM;
283
284	ret = -ENOMEM;
285	obj_in_table = vzalloc(array_size(sizeof(unsigned long),
286					  BITS_TO_LONGS(entries)));
287	if (!obj_in_table)
288		goto out_free;
289
290	err = rhltable_init(&rhlt, &test_rht_params);
291	if (WARN_ON(err))
292		goto out_free;
293
294	k = prandom_u32();
295	ret = 0;
296	for (i = 0; i < entries; i++) {
297		rhl_test_objects[i].value.id = k;
298		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
299				      test_rht_params);
300		if (WARN(err, "error %d on element %d\n", err, i))
301			break;
302		if (err == 0)
303			set_bit(i, obj_in_table);
304	}
305
306	if (err)
307		ret = err;
308
309	pr_info("test %d add/delete pairs into rhlist\n", entries);
310	for (i = 0; i < entries; i++) {
311		struct rhlist_head *h, *pos;
312		struct test_obj_rhl *obj;
313		struct test_obj_val key = {
314			.id = k,
315		};
316		bool found;
317
318		rcu_read_lock();
319		h = rhltable_lookup(&rhlt, &key, test_rht_params);
320		if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
321			rcu_read_unlock();
322			break;
323		}
324
325		if (i) {
326			j = i - 1;
327			rhl_for_each_entry_rcu(obj, pos, h, list_node) {
328				if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
329					break;
330			}
331		}
332
333		cond_resched_rcu();
334
335		found = false;
336
337		rhl_for_each_entry_rcu(obj, pos, h, list_node) {
338			if (pos == &rhl_test_objects[i].list_node) {
339				found = true;
340				break;
341			}
342		}
343
344		rcu_read_unlock();
345
346		if (WARN(!found, "element %d not found", i))
347			break;
348
349		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
350		WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
351		if (err == 0)
352			clear_bit(i, obj_in_table);
353	}
354
355	if (ret == 0 && err)
356		ret = err;
357
358	for (i = 0; i < entries; i++) {
359		WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);
360
361		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
362				      test_rht_params);
363		if (WARN(err, "error %d on element %d\n", err, i))
364			break;
365		if (err == 0)
366			set_bit(i, obj_in_table);
367	}
368
369	pr_info("test %d random rhlist add/delete operations\n", entries);
370	for (j = 0; j < entries; j++) {
371		u32 i = prandom_u32_max(entries);
372		u32 prand = prandom_u32();
373
374		cond_resched();
375
376		if (prand == 0)
377			prand = prandom_u32();
378
379		if (prand & 1) {
380			prand >>= 1;
381			continue;
382		}
383
384		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
385		if (test_bit(i, obj_in_table)) {
386			clear_bit(i, obj_in_table);
387			if (WARN(err, "cannot remove element at slot %d", i))
388				continue;
389		} else {
390			if (WARN(err != -ENOENT, "removed non-existent element %d, error %d not %d",
391			     i, err, -ENOENT))
392				continue;
393		}
394
395		if (prand & 1) {
396			prand >>= 1;
397			continue;
398		}
399
400		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
401		if (err == 0) {
402			if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
403				continue;
404		} else {
405			if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
406				continue;
407		}
408
409		if (prand & 1) {
410			prand >>= 1;
411			continue;
412		}
413
414		i = prandom_u32_max(entries);
415		if (test_bit(i, obj_in_table)) {
416			err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
417			WARN(err, "cannot remove element at slot %d", i);
418			if (err == 0)
419				clear_bit(i, obj_in_table);
420		} else {
421			err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
422			WARN(err, "failed to insert object %d", i);
423			if (err == 0)
424				set_bit(i, obj_in_table);
425		}
426	}
427
428	for (i = 0; i < entries; i++) {
429		cond_resched();
430		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
431		if (test_bit(i, obj_in_table)) {
432			if (WARN(err, "cannot remove element at slot %d", i))
433				continue;
434		} else {
435			if (WARN(err != -ENOENT, "removed non-existent element, error %d not %d",
436				 err, -ENOENT))
437				continue;
438		}
439	}
440
441	rhltable_destroy(&rhlt);
442out_free:
443	vfree(rhl_test_objects);
444	vfree(obj_in_table);
445	return ret;
446}
447
448static int __init test_rhashtable_max(struct test_obj *array,
449				      unsigned int entries)
450{
451	unsigned int i, insert_retries = 0;
452	int err;
453
454	test_rht_params.max_size = roundup_pow_of_two(entries / 8);
455	err = rhashtable_init(&ht, &test_rht_params);
456	if (err)
457		return err;
458
459	for (i = 0; i < ht.max_elems; i++) {
460		struct test_obj *obj = &array[i];
461
462		obj->value.id = i * 2;
463		err = insert_retry(&ht, obj, test_rht_params);
464		if (err > 0)
465			insert_retries += err;
466		else if (err)
467			return err;
468	}
469
470	err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
471	if (err == -E2BIG) {
472		err = 0;
473	} else {
474		pr_info("insert element %u should have failed with %d, got %d\n",
475				ht.max_elems, -E2BIG, err);
476		if (err == 0)
477			err = -1;
478	}
479
480	rhashtable_destroy(&ht);
481
482	return err;
483}
484
485static unsigned int __init print_ht(struct rhltable *rhlt)
486{
487	struct rhashtable *ht;
488	const struct bucket_table *tbl;
489	char buff[512] = "";
490	int offset = 0;
491	unsigned int i, cnt = 0;
492
493	ht = &rhlt->ht;
494	/* Take the mutex to avoid RCU warning */
495	mutex_lock(&ht->mutex);
496	tbl = rht_dereference(ht->tbl, ht);
497	for (i = 0; i < tbl->size; i++) {
498		struct rhash_head *pos, *next;
499		struct test_obj_rhl *p;
500
501		pos = rht_ptr_exclusive(tbl->buckets + i);
502		next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
503
504		if (!rht_is_a_nulls(pos)) {
505			offset += sprintf(buff + offset, "\nbucket[%d] -> ", i);
506		}
507
508		while (!rht_is_a_nulls(pos)) {
509			struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead);
510			offset += sprintf(buff + offset, "[[");
511			do {
512				pos = &list->rhead;
513				list = rht_dereference(list->next, ht);
514				p = rht_obj(ht, pos);
515
516				offset += sprintf(buff + offset, " val %d (tid=%d)%s", p->value.id, p->value.tid,
517					list? ", " : " ");
518				cnt++;
519			} while (list);
520
521			pos = next,
522			next = !rht_is_a_nulls(pos) ?
523				rht_dereference(pos->next, ht) : NULL;
524
525			offset += sprintf(buff + offset, "]]%s", !rht_is_a_nulls(pos) ? " -> " : "");
526		}
527	}
528	printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
529	mutex_unlock(&ht->mutex);
530
531	return cnt;
532}
533
534static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
535				  int cnt, bool slow)
536{
537	struct rhltable *rhlt;
538	unsigned int i, ret;
539	const char *key;
540	int err = 0;
541
542	rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
543	if (WARN_ON(!rhlt))
544		return -EINVAL;
545
546	err = rhltable_init(rhlt, &test_rht_params_dup);
547	if (WARN_ON(err)) {
548		kfree(rhlt);
549		return err;
550	}
551
552	for (i = 0; i < cnt; i++) {
553		rhl_test_objects[i].value.tid = i;
554		key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
555		key += test_rht_params_dup.key_offset;
556
557		if (slow) {
558			err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
559							     &rhl_test_objects[i].list_node.rhead));
560			if (err == -EAGAIN)
561				err = 0;
562		} else
563			err = rhltable_insert(rhlt,
564					      &rhl_test_objects[i].list_node,
565					      test_rht_params_dup);
566		if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
567			goto skip_print;
568	}
569
570	ret = print_ht(rhlt);
571	WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");
572
573skip_print:
574	rhltable_destroy(rhlt);
575	kfree(rhlt);
576
577	return 0;
578}
579
580static int __init test_insert_duplicates_run(void)
581{
582	struct test_obj_rhl rhl_test_objects[3] = {};
583
584	pr_info("test inserting duplicates\n");
585
586	/* two different values that map to same bucket */
587	rhl_test_objects[0].value.id = 1;
588	rhl_test_objects[1].value.id = 21;
589
590	/* and another duplicate with same as [0] value
591	 * which will be second on the bucket list */
592	rhl_test_objects[2].value.id = rhl_test_objects[0].value.id;
593
594	test_insert_dup(rhl_test_objects, 2, false);
595	test_insert_dup(rhl_test_objects, 3, false);
596	test_insert_dup(rhl_test_objects, 2, true);
597	test_insert_dup(rhl_test_objects, 3, true);
598
599	return 0;
600}
601
602static int thread_lookup_test(struct thread_data *tdata)
603{
604	unsigned int entries = tdata->entries;
605	int i, err = 0;
606
607	for (i = 0; i < entries; i++) {
608		struct test_obj *obj;
609		struct test_obj_val key = {
610			.id = i,
611			.tid = tdata->id,
612		};
613
614		obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
615		if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
616			pr_err("  found unexpected object %d-%d\n", key.tid, key.id);
617			err++;
618		} else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
619			pr_err("  object %d-%d not found!\n", key.tid, key.id);
620			err++;
621		} else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
622			pr_err("  wrong object returned (got %d-%d, expected %d-%d)\n",
623			       obj->value.tid, obj->value.id, key.tid, key.id);
624			err++;
625		}
626
627		cond_resched();
628	}
629	return err;
630}
631
632static int threadfunc(void *data)
633{
634	int i, step, err = 0, insert_retries = 0;
635	struct thread_data *tdata = data;
636
637	if (atomic_dec_and_test(&startup_count))
638		wake_up(&startup_wait);
639	if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == -1)) {
640		pr_err("  thread[%d]: interrupted\n", tdata->id);
641		goto out;
642	}
643
644	for (i = 0; i < tdata->entries; i++) {
645		tdata->objs[i].value.id = i;
646		tdata->objs[i].value.tid = tdata->id;
647		err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
648		if (err > 0) {
649			insert_retries += err;
650		} else if (err) {
651			pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
652			       tdata->id);
653			goto out;
654		}
655	}
656	if (insert_retries)
657		pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
658			tdata->id, insert_retries);
659
660	err = thread_lookup_test(tdata);
661	if (err) {
662		pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
663		       tdata->id);
664		goto out;
665	}
666
667	for (step = 10; step > 0; step--) {
668		for (i = 0; i < tdata->entries; i += step) {
669			if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
670				continue;
671			err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
672			                             test_rht_params);
673			if (err) {
674				pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
675				       tdata->id);
676				goto out;
677			}
678			tdata->objs[i].value.id = TEST_INSERT_FAIL;
679
680			cond_resched();
681		}
682		err = thread_lookup_test(tdata);
683		if (err) {
684			pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
685			       tdata->id);
686			goto out;
687		}
688	}
689out:
690	while (!kthread_should_stop()) {
691		set_current_state(TASK_INTERRUPTIBLE);
692		schedule();
693	}
694	return err;
695}
696
697static int __init test_rht_init(void)
698{
699	unsigned int entries;
700	int i, err, started_threads = 0, failed_threads = 0;
701	u64 total_time = 0;
702	struct thread_data *tdata;
703	struct test_obj *objs;
704
705	if (parm_entries < 0)
706		parm_entries = 1;
707
708	entries = min(parm_entries, MAX_ENTRIES);
709
710	test_rht_params.automatic_shrinking = shrinking;
711	test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
712	test_rht_params.nelem_hint = size;
713
714	objs = vzalloc(array_size(sizeof(struct test_obj),
715				  test_rht_params.max_size + 1));
716	if (!objs)
717		return -ENOMEM;
718
719	pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
720		size, max_size, shrinking);
721
722	for (i = 0; i < runs; i++) {
723		s64 time;
724
725		pr_info("Test %02d:\n", i);
726		memset(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));
727
728		err = rhashtable_init(&ht, &test_rht_params);
729		if (err < 0) {
730			pr_warn("Test failed: Unable to initialize hashtable: %d\n",
731				err);
732			continue;
733		}
734
735		time = test_rhashtable(&ht, objs, entries);
736		rhashtable_destroy(&ht);
737		if (time < 0) {
738			vfree(objs);
739			pr_warn("Test failed: return code %lld\n", time);
740			return -EINVAL;
741		}
742
743		total_time += time;
744	}
745
746	pr_info("test if its possible to exceed max_size %d: %s\n",
747			test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
748			"no, ok" : "YES, failed");
749	vfree(objs);
750
751	do_div(total_time, runs);
752	pr_info("Average test time: %llu\n", total_time);
753
754	test_insert_duplicates_run();
755
756	if (!tcount)
757		return 0;
758
759	pr_info("Testing concurrent rhashtable access from %d threads\n",
760	        tcount);
761	atomic_set(&startup_count, tcount);
762	tdata = vzalloc(array_size(tcount, sizeof(struct thread_data)));
763	if (!tdata)
764		return -ENOMEM;
765	objs  = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
766	if (!objs) {
767		vfree(tdata);
768		return -ENOMEM;
769	}
770
771	test_rht_params.max_size = max_size ? :
772	                           roundup_pow_of_two(tcount * entries);
773	err = rhashtable_init(&ht, &test_rht_params);
774	if (err < 0) {
775		pr_warn("Test failed: Unable to initialize hashtable: %d\n",
776			err);
777		vfree(tdata);
778		vfree(objs);
779		return -EINVAL;
780	}
781	for (i = 0; i < tcount; i++) {
782		tdata[i].id = i;
783		tdata[i].entries = entries;
784		tdata[i].objs = objs + i * entries;
785		tdata[i].task = kthread_run(threadfunc, &tdata[i],
786		                            "rhashtable_thrad[%d]", i);
787		if (IS_ERR(tdata[i].task)) {
788			pr_err(" kthread_run failed for thread %d\n", i);
789			atomic_dec(&startup_count);
790		} else {
791			started_threads++;
792		}
793	}
794	if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == 0))
795		pr_err("  wait_event interruptible failed\n");
796	/* count is 0 now, set it to -1 and wake up all threads together */
797	atomic_dec(&startup_count);
798	wake_up_all(&startup_wait);
799	for (i = 0; i < tcount; i++) {
800		if (IS_ERR(tdata[i].task))
801			continue;
802		if ((err = kthread_stop(tdata[i].task))) {
803			pr_warn("Test failed: thread %d returned: %d\n",
804			        i, err);
805			failed_threads++;
806		}
807	}
808	rhashtable_destroy(&ht);
809	vfree(tdata);
810	vfree(objs);
811
812	/*
813	 * rhltable_remove is very expensive, default values can cause test
814	 * to run for 2 minutes or more,  use a smaller number instead.
815	 */
816	err = test_rhltable(entries / 16);
817	pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
818	        started_threads, failed_threads, err);
819	return 0;
820}
821
822static void __exit test_rht_exit(void)
823{
824}
825
826module_init(test_rht_init);
827module_exit(test_rht_exit);
828
829MODULE_LICENSE("GPL v2");