The get_rcu_tasks_trace_gp_kthread() is used by rcuscale to diagnose
bugs involving the RCU Tasks Trace grace-period kthread, which now no
longer exists.  This commit therefore removes this function.

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>
---
 include/linux/rcupdate_trace.h | 1 -
 kernel/rcu/rcuscale.c          | 1 -
 kernel/rcu/tasks.h             | 6 ------
 3 files changed, 8 deletions(-)

diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h
index ffd4dcd6339ae4..0bd47f12ecd17b 100644
--- a/include/linux/rcupdate_trace.h
+++ b/include/linux/rcupdate_trace.h
@@ -137,7 +137,6 @@ static inline void rcu_barrier_tasks_trace(void)
 
 // Placeholders to enable stepwise transition.
 void __init rcu_tasks_trace_suppress_unused(void);
-struct task_struct *get_rcu_tasks_trace_gp_kthread(void);
 
 #else
 /*
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index 16ba9050dab66b..17d038e26b65de 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -411,7 +411,6 @@ static struct rcu_scale_ops tasks_tracing_ops = {
 	.gp_barrier	= rcu_barrier_tasks_trace,
 	.sync		= synchronize_rcu_tasks_trace,
 	.exp_sync	= synchronize_rcu_tasks_trace,
-	.rso_gp_kthread	= get_rcu_tasks_trace_gp_kthread,
 	.name		= "tasks-tracing"
 };
 
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 4fb61b3c78283d..e70609c85ece5d 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1467,12 +1467,6 @@ void __init rcu_tasks_trace_suppress_unused(void)
 	rcu_tasks_torture_stats_print_generic(NULL, NULL, NULL, NULL);
 }
 
-struct task_struct *get_rcu_tasks_trace_gp_kthread(void)
-{
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(get_rcu_tasks_trace_gp_kthread);
-
 #endif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */
 
 #ifndef CONFIG_TINY_RCU
-- 
2.40.1