rcutorture: Add torture tests for RCU-tasks

This commit adds torture tests for RCU-tasks.  It also fixes a bug that
would segfault for an RCU flavor lacking a callback-barrier function.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

1 files changed, 49 insertions, 1 deletions

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 178716713e11..75b1abf78c48 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -601,6 +601,52 @@ static struct rcu_torture_ops sched_ops = {
         .name           = "sched"
 };
 
+#ifdef CONFIG_TASKS_RCU
+
+/*
+ * Definitions for RCU-tasks torture testing.
+ */
+
+static int tasks_torture_read_lock(void)
+{
+        return 0;
+}
+
+static void tasks_torture_read_unlock(int idx)
+{
+}
+
+static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
+{
+        call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops tasks_ops = {
+        .ttype          = RCU_TASKS_FLAVOR,
+        .init           = rcu_sync_torture_init,
+        .readlock       = tasks_torture_read_lock,
+        .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+        .readunlock     = tasks_torture_read_unlock,
+        .completed      = rcu_no_completed,
+        .deferred_free  = rcu_tasks_torture_deferred_free,
+        .sync           = synchronize_rcu_tasks,
+        .exp_sync       = synchronize_rcu_tasks,
+        .call           = call_rcu_tasks,
+        .cb_barrier     = rcu_barrier_tasks,
+        .fqs            = NULL,
+        .stats          = NULL,
+        .irq_capable    = 1,
+        .name           = "tasks"
+};
+
+#define RCUTORTURE_TASKS_OPS &tasks_ops,
+
+#else /* #ifdef CONFIG_TASKS_RCU */
+
+#define RCUTORTURE_TASKS_OPS
+
+#endif /* #else #ifdef CONFIG_TASKS_RCU */
+
 /*
  * RCU torture priority-boost testing.  Runs one real-time thread per
  * CPU for moderate bursts, repeatedly registering RCU callbacks and
@@ -1295,7 +1341,8 @@ static int rcu_torture_barrier_cbs(void *arg)
                 if (atomic_dec_and_test(&barrier_cbs_count))
                         wake_up(&barrier_wq);
         } while (!torture_must_stop());
-        cur_ops->cb_barrier();
+        if (cur_ops->cb_barrier != NULL)
+                cur_ops->cb_barrier();
         destroy_rcu_head_on_stack(&rcu);
         torture_kthread_stopping("rcu_torture_barrier_cbs");
         return 0;
@@ -1534,6 +1581,7 @@ rcu_torture_init(void)
         int firsterr = 0;
         static struct rcu_torture_ops *torture_ops[] = {
                 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
+                RCUTORTURE_TASKS_OPS
         };
 
         if (!torture_init_begin(torture_type, verbose, &rcutorture_runnable))