locking/ww_mutex: Add ww_mutex to locktorture test

Although ww_mutexes degenerate into mutexes, it would be useful to
torture the deadlock handling between multiple ww_mutexes in addition to
torturing the regular mutexes.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-3-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 81 insertions, 0 deletions

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f8c5af52a131..9bffedd82884 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -372,6 +372,78 @@ static struct lock_torture_ops mutex_lock_ops = {
         .name           = "mutex_lock"
 };
 
+#include <linux/ww_mutex.h>
+static DEFINE_WW_CLASS(torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
+
+static int torture_ww_mutex_lock(void)
+__acquires(torture_ww_mutex_0)
+__acquires(torture_ww_mutex_1)
+__acquires(torture_ww_mutex_2)
+{
+        LIST_HEAD(list);
+        struct reorder_lock {
+                struct list_head link;
+                struct ww_mutex *lock;
+        } locks[3], *ll, *ln;
+        struct ww_acquire_ctx ctx;
+
+        locks[0].lock = &torture_ww_mutex_0;
+        list_add(&locks[0].link, &list);
+
+        locks[1].lock = &torture_ww_mutex_1;
+        list_add(&locks[1].link, &list);
+
+        locks[2].lock = &torture_ww_mutex_2;
+        list_add(&locks[2].link, &list);
+
+        ww_acquire_init(&ctx, &torture_ww_class);
+
+        list_for_each_entry(ll, &list, link) {
+                int err;
+
+                err = ww_mutex_lock(ll->lock, &ctx);
+                if (!err)
+                        continue;
+
+                ln = ll;
+                list_for_each_entry_continue_reverse(ln, &list, link)
+                        ww_mutex_unlock(ln->lock);
+
+                if (err != -EDEADLK)
+                        return err;
+
+                ww_mutex_lock_slow(ll->lock, &ctx);
+                list_move(&ll->link, &list);
+        }
+
+        ww_acquire_fini(&ctx);
+        return 0;
+}
+
+static void torture_ww_mutex_unlock(void)
+__releases(torture_ww_mutex_0)
+__releases(torture_ww_mutex_1)
+__releases(torture_ww_mutex_2)
+{
+        ww_mutex_unlock(&torture_ww_mutex_0);
+        ww_mutex_unlock(&torture_ww_mutex_1);
+        ww_mutex_unlock(&torture_ww_mutex_2);
+}
+
+static struct lock_torture_ops ww_mutex_lock_ops = {
+        .writelock      = torture_ww_mutex_lock,
+        .write_delay    = torture_mutex_delay,
+        .task_boost     = torture_boost_dummy,
+        .writeunlock    = torture_ww_mutex_unlock,
+        .readlock       = NULL,
+        .read_delay     = NULL,
+        .readunlock     = NULL,
+        .name           = "ww_mutex_lock"
+};
+
 #ifdef CONFIG_RT_MUTEXES
 static DEFINE_RT_MUTEX(torture_rtmutex);
 
@@ -793,6 +865,7 @@ static int __init lock_torture_init(void)
                 &spin_lock_ops, &spin_lock_irq_ops,
                 &rw_lock_ops, &rw_lock_irq_ops,
                 &mutex_lock_ops,
+                &ww_mutex_lock_ops,
 #ifdef CONFIG_RT_MUTEXES
                 &rtmutex_lock_ops,
 #endif
diff --git a/tools/testing/selftests/rcutorture/configs/lock/CFLIST b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
index b9611c523723..41bae5824339 100644
--- a/tools/testing/selftests/rcutorture/configs/lock/CFLIST
+++ b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
@@ -4,3 +4,4 @@ LOCK03
 LOCK04
 LOCK05
 LOCK06
+LOCK07
diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK07 b/tools/testing/selftests/rcutorture/configs/lock/LOCK07
new file mode 100644
index 000000000000..1d1da1477fc3
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK07
@@ -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/LOCK07.boot b/tools/testing/selftests/rcutorture/configs/lock/LOCK07.boot
new file mode 100644
index 000000000000..97dadd1a9e45
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK07.boot
@@ -0,0 +1 @@
+locktorture.torture_type=ww_mutex_lock