srcu: Create an rcu_tasks_trace_expedite_current() function

This commit creates an rcu_tasks_trace_expedite_current() function
that expedites the current (and possibly the next) RCU Tasks Trace
grace period.

If the current RCU Tasks Trace grace period is already waiting, that wait
will complete before the expediting takes effect.  If there is no RCU
Tasks Trace  grace period in flight, this function might well create one.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bpf@vger.kernel.org
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h
index f47ba9c074601c0deedbacb9396ea451de1f4700..cee89e51e45cbbbe4097b55e354b2562e02807fd 100644 (file)
--- a/include/linux/rcupdate_trace.h
+++ b/include/linux/rcupdate_trace.h
@@ -184,6 +184,20 @@ static inline void rcu_barrier_tasks_trace(void)
        srcu_barrier(&rcu_tasks_trace_srcu_struct);
 }
 
+/**
+ * rcu_tasks_trace_expedite_current - Expedite the current Tasks Trace RCU grace period
+ *
+ * Cause the current Tasks Trace RCU grace period to become expedited.
+ * The grace period following the current one might also be expedited.
+ * If there is no current grace period, one might be created.  If the
+ * current grace period is currently sleeping, that sleep will complete
+ * before expediting will take effect.
+ */
+static inline void rcu_tasks_trace_expedite_current(void)
+{
+       srcu_expedite_current(&rcu_tasks_trace_srcu_struct);
+}
+
 // Placeholders to enable stepwise transition.
 void __init rcu_tasks_trace_suppress_unused(void);