[PATCH rcu 01/20] rcu-tasks: Fix warning for unused tasks_rcu_exit_srcu

["Paul E. McKenney" <paulmck@kernel.org>]

The tasks_rcu_exit_srcu variable is used only by kernels built
with CONFIG_TASKS_RCU=y, but is defined for all kernesl with
CONFIG_TASKS_RCU_GENERIC=y.  Therefore, in kernels built with
CONFIG_TASKS_RCU_GENERIC=y but CONFIG_TASKS_RCU=n, this gives
a "defined but not used" warning.

This commit therefore moves this variable under CONFIG_TASKS_RCU.

Link: https://lore.kernel.org/oe-kbuild-all/202303191536.XzMSyzTl-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tasks.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index bfb5e1549f2b..185358c2f08d 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -136,8 +136,10 @@ static struct rcu_tasks rt_name =							\
 	.kname = #rt_name,								\
 }
 
+#ifdef CONFIG_TASKS_RCU
 /* Track exiting tasks in order to allow them to be waited for. */
 DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu);
+#endif
 
 /* Avoid IPIing CPUs early in the grace period. */
 #define RCU_TASK_IPI_DELAY (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) ? HZ / 2 : 0)
-- 
2.40.0.rc2