rcu: Silence unused-variable warnings

The "idle" variable in both rcu_eqs_enter_common() and
rcu_eqs_exit_common() is only used in a WARN_ON_ONCE().  If the kernel
is built disabling WARN_ON_ONCE(), the compiler will complain (rightly)
that "idle" is unused.  This commit therefore adds a __maybe_unused to
the declaration of both variables.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 8eb9cfd9e2b1..e6f2e8f14140 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -371,7 +371,8 @@ static void rcu_eqs_enter_common(struct rcu_dynticks *rdtp, long long oldval,
 {
         trace_rcu_dyntick(TPS("Start"), oldval, rdtp->dynticks_nesting);
         if (!user && !is_idle_task(current)) {
-                struct task_struct *idle = idle_task(smp_processor_id());
+                struct task_struct *idle __maybe_unused =
+                        idle_task(smp_processor_id());
 
                 trace_rcu_dyntick(TPS("Error on entry: not idle task"), oldval, 0);
                 ftrace_dump(DUMP_ORIG);
@@ -508,7 +509,8 @@ static void rcu_eqs_exit_common(struct rcu_dynticks *rdtp, long long oldval,
         rcu_cleanup_after_idle(smp_processor_id());
         trace_rcu_dyntick(TPS("End"), oldval, rdtp->dynticks_nesting);
         if (!user && !is_idle_task(current)) {
-                struct task_struct *idle = idle_task(smp_processor_id());
+                struct task_struct *idle __maybe_unused =
+                        idle_task(smp_processor_id());
 
                 trace_rcu_dyntick(TPS("Error on exit: not idle task"),
                                   oldval, rdtp->dynticks_nesting);