rcutorture: Add forward-progress checking for writer

[deliverable/linux.git] / kernel / rcu / tree.c

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0c47e300210ad61c3d79854426150fd5246f5750..3d15b5a82ae818bb7d105ad020f789262d0f5009 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -293,6 +293,39 @@ void rcutorture_record_test_transition(void)
 }
 EXPORT_SYMBOL_GPL(rcutorture_record_test_transition);
 
+/*
+ * Send along grace-period-related data for rcutorture diagnostics.
+ */
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+                           unsigned long *gpnum, unsigned long *completed)
+{
+       struct rcu_state *rsp = NULL;
+
+       switch (test_type) {
+       case RCU_FLAVOR:
+               rsp = rcu_state;
+               break;
+       case RCU_BH_FLAVOR:
+               rsp = &rcu_bh_state;
+               break;
+       case RCU_SCHED_FLAVOR:
+               rsp = &rcu_sched_state;
+               break;
+       default:
+               break;
+       }
+       if (rsp != NULL) {
+               *flags = ACCESS_ONCE(rsp->gp_flags);
+               *gpnum = ACCESS_ONCE(rsp->gpnum);
+               *completed = ACCESS_ONCE(rsp->completed);
+               return;
+       }
+       *flags = 0;
+       *gpnum = 0;
+       *completed = 0;
+}
+EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
+
 /*
  * Record the number of writer passes through the current rcutorture test.
  * This is also used to correlate debugfs tracing stats with the rcutorture