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Commit 3e7b2ec4 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

rhashtable: Check for count mismatch while iterating in selftest 



Verify whether both the lock and RCU protected iterators see all
test entries before and after expanding and shrinking has been
performed. Also verify whether the number of entries in the hashtable
remains stable during expansion and shrinking.

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 08dcf9fd

lib/rhashtable.c

+20 −7
Original line number Diff line number Diff line
@@ -653,15 +653,15 @@ static int __init test_rht_lookup(struct rhashtable *ht) 
	return 0;

}



static void test_bucket_stats(struct rhashtable *ht,

				     struct bucket_table *tbl,

				     bool quiet)

static void test_bucket_stats(struct rhashtable *ht, bool quiet)

{

	unsigned int cnt, i, total = 0;

	unsigned int cnt, rcu_cnt, i, total = 0;

	struct test_obj *obj;

	struct bucket_table *tbl;



	tbl = rht_dereference_rcu(ht->tbl, ht);

	for (i = 0; i < tbl->size; i++) {

		cnt = 0;

		rcu_cnt = cnt = 0;



		if (!quiet)

			pr_info(" [%#4x/%zu]", i, tbl->size);
@@ -673,6 +673,13 @@ static void test_bucket_stats(struct rhashtable *ht, 
				pr_cont(" [%p],", obj);

		}



		rht_for_each_entry_rcu(obj, tbl->buckets[i], node)

			rcu_cnt++;



		if (rcu_cnt != cnt)

			pr_warn("Test failed: Chain count mismach %d != %d",

				cnt, rcu_cnt);



		if (!quiet)

			pr_cont("\n  [%#x] first element: %p, chain length: %u\n",

				i, tbl->buckets[i], cnt);
@@ -680,6 +687,9 @@ static void test_bucket_stats(struct rhashtable *ht, 


	pr_info("  Traversal complete: counted=%u, nelems=%zu, entries=%d\n",

		total, ht->nelems, TEST_ENTRIES);



	if (total != ht->nelems || total != TEST_ENTRIES)

		pr_warn("Test failed: Total count mismatch ^^^");

}



static int __init test_rhashtable(struct rhashtable *ht)
@@ -710,8 +720,7 @@ static int __init test_rhashtable(struct rhashtable *ht) 
	}



	rcu_read_lock();

	tbl = rht_dereference_rcu(ht->tbl, ht);

	test_bucket_stats(ht, tbl, true);

	test_bucket_stats(ht, true);

	test_rht_lookup(ht);

	rcu_read_unlock();
@@ -735,6 +744,10 @@ static int __init test_rhashtable(struct rhashtable *ht) 
		rcu_read_unlock();

	}



	rcu_read_lock();

	test_bucket_stats(ht, true);

	rcu_read_unlock();



	pr_info("  Deleting %d keys\n", TEST_ENTRIES);

	for (i = 0; i < TEST_ENTRIES; i++) {

		u32 key = i * 2;