[PATCH v4 3/4] locktorture: Add nested locking to rtmutex torture tests

[John Stultz <jstultz@google.com>]

This patch adds randomized nested locking to the rtmutex torture
tests. Additionally it adds LOCK09 config files for testing
rtmutexes with nested locking.

Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Co-developed-by: Connor O'Brien <connoro@google.com>
Signed-off-by: Connor O'Brien <connoro@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
---
v2:
* Add LOCK09 config file suggested by Paul McKenney
v3:
* Minor commit message tweaks and naming changes
  suggested by Davidlohr Bueso
v4:
* Add co-developed tag
---
 kernel/locking/locktorture.c                  | 35 +++++++++++++++++++
 .../selftests/rcutorture/configs/lock/CFLIST  |  1 +
 .../selftests/rcutorture/configs/lock/LOCK09  |  6 ++++
 .../rcutorture/configs/lock/LOCK09.boot       |  1 +
 4 files changed, 43 insertions(+)
 create mode 100644 tools/testing/selftests/rcutorture/configs/lock/LOCK09
 create mode 100644 tools/testing/selftests/rcutorture/configs/lock/LOCK09.boot

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 8a08c004aa80..fd8b2b007c26 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -506,6 +506,28 @@ static struct lock_torture_ops ww_mutex_lock_ops = {
 
 #ifdef CONFIG_RT_MUTEXES
 static DEFINE_RT_MUTEX(torture_rtmutex);
+static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS];
+static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS];
+
+static void torture_rtmutex_init(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_NESTED_LOCKS; i++)
+		__rt_mutex_init(&torture_nested_rtmutexes[i], __func__,
+				&nested_rtmutex_keys[i]);
+}
+
+static int torture_rtmutex_nested_lock(int tid __maybe_unused,
+				       u32 lockset)
+{
+	int i;
+
+	for (i = 0; i < nested_locks; i++)
+		if (lockset & (1 << i))
+			rt_mutex_lock(&torture_nested_rtmutexes[i]);
+	return 0;
+}
 
 static int torture_rtmutex_lock(int tid __maybe_unused)
 __acquires(torture_rtmutex)
@@ -570,11 +592,24 @@ __releases(torture_rtmutex)
 	rt_mutex_unlock(&torture_rtmutex);
 }
 
+static void torture_rtmutex_nested_unlock(int tid __maybe_unused,
+					  u32 lockset)
+{
+	int i;
+
+	for (i = nested_locks - 1; i >= 0; i--)
+		if (lockset & (1 << i))
+			rt_mutex_unlock(&torture_nested_rtmutexes[i]);
+}
+
 static struct lock_torture_ops rtmutex_lock_ops = {
+	.init		= torture_rtmutex_init,
+	.nested_lock	= torture_rtmutex_nested_lock,
 	.writelock	= torture_rtmutex_lock,
 	.write_delay	= torture_rtmutex_delay,
 	.task_boost     = torture_rtmutex_boost,
 	.writeunlock	= torture_rtmutex_unlock,
+	.nested_unlock	= torture_rtmutex_nested_unlock,
 	.readlock       = NULL,
 	.read_delay     = NULL,
 	.readunlock     = NULL,
diff --git a/tools/testing/selftests/rcutorture/configs/lock/CFLIST b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
index a48bba0d35a6..28e23d05d5a5 100644
--- a/tools/testing/selftests/rcutorture/configs/lock/CFLIST
+++ b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
@@ -6,3 +6,4 @@ LOCK05
 LOCK06
 LOCK07
 LOCK08
+LOCK09
diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK09 b/tools/testing/selftests/rcutorture/configs/lock/LOCK09
new file mode 100644
index 000000000000..1d1da1477fc3
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK09
@@ -0,0 +1,6 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=4
+CONFIG_HOTPLUG_CPU=y
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK09.boot b/tools/testing/selftests/rcutorture/configs/lock/LOCK09.boot
new file mode 100644
index 000000000000..fd5eff148a93
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK09.boot
@@ -0,0 +1 @@
+locktorture.torture_type=rtmutex_lock locktorture.nested_locks=8
-- 
2.39.2.637.g21b0678d19-goog