[PATCH RT 5/6] rwsem: Provide down_read_non_owner() and up_read_non_owner() for -RT

[Steven Rostedt]

5.4.54-rt33-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

The rwsem implementation on -RT allows multiple reader and there is no
owner tracking anymore.
We can provide down_read_non_owner() and up_read_non_owner() by skipping
the owner check bits which are only available in the !RT implementation.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 kernel/locking/rwsem.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 0d11ba11a32a..0325c721f9b3 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1616,15 +1616,15 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
 }
 EXPORT_SYMBOL(_down_write_nest_lock);
 
-#ifndef CONFIG_PREEMPT_RT
 void down_read_non_owner(struct rw_semaphore *sem)
 {
 	might_sleep();
 	__down_read(sem);
+#ifndef CONFIG_PREEMPT_RT
 	__rwsem_set_reader_owned(sem, NULL);
+#endif
 }
 EXPORT_SYMBOL(down_read_non_owner);
-#endif
 
 void down_write_nested(struct rw_semaphore *sem, int subclass)
 {
@@ -1649,13 +1649,13 @@ int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
 }
 EXPORT_SYMBOL(down_write_killable_nested);
 
-#ifndef CONFIG_PREEMPT_RT
 void up_read_non_owner(struct rw_semaphore *sem)
 {
+#ifndef CONFIG_PREEMPT_RT
 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+#endif
 	__up_read(sem);
 }
 EXPORT_SYMBOL(up_read_non_owner);
-#endif
 
 #endif
-- 
2.28.0