[PATCH 1/3] test-ww_mutex: Extend ww_mutex tests to test both classes of ww_mutexes

[John Stultz]

Currently the test-ww_mutex tool only utilizes the wait-die
class of ww_mutexes, and thus isn't very helpful in exercising
the wait-wound class of ww_mutexes.

So extend the test to exercise both classes of ww_mutexes for
all of the subtests.

Signed-off-by: John Stultz <jstultz@xxxxxxxxxx>
---
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: "Paul E . McKenney" <paulmck@xxxxxxxxxx>
Cc: Joel Fernandes <joelagnelf@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Cc: kernel-team@xxxxxxxxxxx
---
 kernel/locking/test-ww_mutex.c | 114 +++++++++++++++++++++------------
 1 file changed, 73 insertions(+), 41 deletions(-)

diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index bcb1b9fea5880..20f509ca17e16 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -13,7 +13,8 @@
 #include <linux/slab.h>
 #include <linux/ww_mutex.h>
 
-static DEFINE_WD_CLASS(ww_class);
+static DEFINE_WD_CLASS(wd_class);
+static DEFINE_WW_CLASS(ww_class);
 struct workqueue_struct *wq;
 
 #ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
@@ -54,16 +55,16 @@ static void test_mutex_work(struct work_struct *work)
 	ww_mutex_unlock(&mtx->mutex);
 }
 
-static int __test_mutex(unsigned int flags)
+static int __test_mutex(struct ww_class *class, 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_mutex_init(&mtx.mutex, class);
 	if (flags & TEST_MTX_CTX)
-		ww_acquire_init(&ctx, &ww_class);
+		ww_acquire_init(&ctx, class);
 
 	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
 	init_completion(&mtx.ready);
@@ -106,13 +107,13 @@ static int __test_mutex(unsigned int flags)
 #undef TIMEOUT
 }
 
-static int test_mutex(void)
+static int test_mutex(struct ww_class *class)
 {
 	int ret;
 	int i;
 
 	for (i = 0; i < __TEST_MTX_LAST; i++) {
-		ret = __test_mutex(i);
+		ret = __test_mutex(class, i);
 		if (ret)
 			return ret;
 	}
@@ -120,15 +121,15 @@ static int test_mutex(void)
 	return 0;
 }
 
-static int test_aa(bool trylock)
+static int test_aa(struct ww_class *class, bool trylock)
 {
 	struct ww_mutex mutex;
 	struct ww_acquire_ctx ctx;
 	int ret;
 	const char *from = trylock ? "trylock" : "lock";
 
-	ww_mutex_init(&mutex, &ww_class);
-	ww_acquire_init(&ctx, &ww_class);
+	ww_mutex_init(&mutex, class);
+	ww_acquire_init(&ctx, class);
 
 	if (!trylock) {
 		ret = ww_mutex_lock(&mutex, &ctx);
@@ -177,6 +178,7 @@ static int test_aa(bool trylock)
 
 struct test_abba {
 	struct work_struct work;
+	struct ww_class *class;
 	struct ww_mutex a_mutex;
 	struct ww_mutex b_mutex;
 	struct completion a_ready;
@@ -191,7 +193,7 @@ static void test_abba_work(struct work_struct *work)
 	struct ww_acquire_ctx ctx;
 	int err;
 
-	ww_acquire_init_noinject(&ctx, &ww_class);
+	ww_acquire_init_noinject(&ctx, abba->class);
 	if (!abba->trylock)
 		ww_mutex_lock(&abba->b_mutex, &ctx);
 	else
@@ -217,23 +219,24 @@ static void test_abba_work(struct work_struct *work)
 	abba->result = err;
 }
 
-static int test_abba(bool trylock, bool resolve)
+static int test_abba(struct ww_class *class, bool trylock, 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);
+	ww_mutex_init(&abba.a_mutex, class);
+	ww_mutex_init(&abba.b_mutex, class);
 	INIT_WORK_ONSTACK(&abba.work, test_abba_work);
 	init_completion(&abba.a_ready);
 	init_completion(&abba.b_ready);
+	abba.class = class;
 	abba.trylock = trylock;
 	abba.resolve = resolve;
 
 	schedule_work(&abba.work);
 
-	ww_acquire_init_noinject(&ctx, &ww_class);
+	ww_acquire_init_noinject(&ctx, class);
 	if (!trylock)
 		ww_mutex_lock(&abba.a_mutex, &ctx);
 	else
@@ -278,6 +281,7 @@ static int test_abba(bool trylock, bool resolve)
 
 struct test_cycle {
 	struct work_struct work;
+	struct ww_class *class;
 	struct ww_mutex a_mutex;
 	struct ww_mutex *b_mutex;
 	struct completion *a_signal;
@@ -291,7 +295,7 @@ static void test_cycle_work(struct work_struct *work)
 	struct ww_acquire_ctx ctx;
 	int err, erra = 0;
 
-	ww_acquire_init_noinject(&ctx, &ww_class);
+	ww_acquire_init_noinject(&ctx, cycle->class);
 	ww_mutex_lock(&cycle->a_mutex, &ctx);
 
 	complete(cycle->a_signal);
@@ -314,7 +318,7 @@ static void test_cycle_work(struct work_struct *work)
 	cycle->result = err ?: erra;
 }
 
-static int __test_cycle(unsigned int nthreads)
+static int __test_cycle(struct ww_class *class, unsigned int nthreads)
 {
 	struct test_cycle *cycles;
 	unsigned int n, last = nthreads - 1;
@@ -327,7 +331,8 @@ static int __test_cycle(unsigned int nthreads)
 	for (n = 0; n < nthreads; n++) {
 		struct test_cycle *cycle = &cycles[n];
 
-		ww_mutex_init(&cycle->a_mutex, &ww_class);
+		cycle->class = class;
+		ww_mutex_init(&cycle->a_mutex, class);
 		if (n == last)
 			cycle->b_mutex = &cycles[0].a_mutex;
 		else
@@ -367,13 +372,13 @@ static int __test_cycle(unsigned int nthreads)
 	return ret;
 }
 
-static int test_cycle(unsigned int ncpus)
+static int test_cycle(struct ww_class *class, unsigned int ncpus)
 {
 	unsigned int n;
 	int ret;
 
 	for (n = 2; n <= ncpus + 1; n++) {
-		ret = __test_cycle(n);
+		ret = __test_cycle(class, n);
 		if (ret)
 			return ret;
 	}
@@ -384,6 +389,7 @@ static int test_cycle(unsigned int ncpus)
 struct stress {
 	struct work_struct work;
 	struct ww_mutex *locks;
+	struct ww_class *class;
 	unsigned long timeout;
 	int nlocks;
 };
@@ -443,7 +449,7 @@ static void stress_inorder_work(struct work_struct *work)
 		int contended = -1;
 		int n, err;
 
-		ww_acquire_init(&ctx, &ww_class);
+		ww_acquire_init(&ctx, stress->class);
 retry:
 		err = 0;
 		for (n = 0; n < nlocks; n++) {
@@ -511,7 +517,7 @@ static void stress_reorder_work(struct work_struct *work)
 	order = NULL;
 
 	do {
-		ww_acquire_init(&ctx, &ww_class);
+		ww_acquire_init(&ctx, stress->class);
 
 		list_for_each_entry(ll, &locks, link) {
 			err = ww_mutex_lock(ll->lock, &ctx);
@@ -570,7 +576,7 @@ static void stress_one_work(struct work_struct *work)
 #define STRESS_ONE BIT(2)
 #define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
 
-static int stress(int nlocks, int nthreads, unsigned int flags)
+static int stress(struct ww_class *class, int nlocks, int nthreads, unsigned int flags)
 {
 	struct ww_mutex *locks;
 	struct stress *stress_array;
@@ -588,7 +594,7 @@ static int stress(int nlocks, int nthreads, unsigned int flags)
 	}
 
 	for (n = 0; n < nlocks; n++)
-		ww_mutex_init(&locks[n], &ww_class);
+		ww_mutex_init(&locks[n], class);
 
 	count = 0;
 	for (n = 0; nthreads; n++) {
@@ -617,6 +623,7 @@ static int stress(int nlocks, int nthreads, unsigned int flags)
 		stress = &stress_array[count++];
 
 		INIT_WORK(&stress->work, fn);
+		stress->class = class;
 		stress->locks = locks;
 		stress->nlocks = nlocks;
 		stress->timeout = jiffies + 2*HZ;
@@ -635,57 +642,82 @@ static int stress(int nlocks, int nthreads, unsigned int flags)
 	return 0;
 }
 
-static int __init test_ww_mutex_init(void)
+static int __init run_tests(struct ww_class *class)
 {
 	int ncpus = num_online_cpus();
 	int ret, i;
 
-	printk(KERN_INFO "Beginning ww mutex selftests\n");
-
-	prandom_seed_state(&rng, get_random_u64());
-
-	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
-	if (!wq)
-		return -ENOMEM;
-
-	ret = test_mutex();
+	ret = test_mutex(class);
 	if (ret)
 		return ret;
 
-	ret = test_aa(false);
+	ret = test_aa(class, false);
 	if (ret)
 		return ret;
 
-	ret = test_aa(true);
+	ret = test_aa(class, true);
 	if (ret)
 		return ret;
 
 	for (i = 0; i < 4; i++) {
-		ret = test_abba(i & 1, i & 2);
+		ret = test_abba(class, i & 1, i & 2);
 		if (ret)
 			return ret;
 	}
 
-	ret = test_cycle(ncpus);
+	ret = test_cycle(class, ncpus);
 	if (ret)
 		return ret;
 
-	ret = stress(16, 2*ncpus, STRESS_INORDER);
+	ret = stress(class, 16, 2*ncpus, STRESS_INORDER);
 	if (ret)
 		return ret;
 
-	ret = stress(16, 2*ncpus, STRESS_REORDER);
+	ret = stress(class, 16, 2*ncpus, STRESS_REORDER);
 	if (ret)
 		return ret;
 
-	ret = stress(2046, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
+	ret = stress(class, 2046, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
 	if (ret)
 		return ret;
 
-	printk(KERN_INFO "All ww mutex selftests passed\n");
 	return 0;
 }
 
+static int __init run_test_classes(void)
+{
+	int ret;
+
+	pr_info("Beginning ww (wound) mutex selftests\n");
+
+	ret = run_tests(&ww_class);
+	if (ret)
+		return ret;
+
+	pr_info("Beginning ww (die) mutex selftests\n");
+	ret = run_tests(&wd_class);
+	if (ret)
+		return ret;
+
+	pr_info("All ww mutex selftests passed\n");
+	return 0;
+}
+
+static int __init test_ww_mutex_init(void)
+{
+	int ret;
+
+	prandom_seed_state(&rng, get_random_u64());
+
+	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
+	if (!wq)
+		return -ENOMEM;
+
+	ret = run_test_classes();
+
+	return ret;
+}
+
 static void __exit test_ww_mutex_exit(void)
 {
 	destroy_workqueue(wq);
-- 
2.50.1.565.gc32cd1483b-goog