ftrace: Be first to run code modification on modules

[firefly-linux-kernel-4.4.55.git] / kernel / rwsem.c

diff --git a/kernel/rwsem.c b/kernel/rwsem.c
index 6850f53e02d82e023954df56f5230b4033e80b73..b3c6c3fcd8474237a2e41ab4db87ee04c2435b7b 100644 (file)
--- a/kernel/rwsem.c
+++ b/kernel/rwsem.c
@@ -116,6 +116,16 @@ void down_read_nested(struct rw_semaphore *sem, int subclass)
 
 EXPORT_SYMBOL(down_read_nested);
 
+void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
+{
+       might_sleep();
+       rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);
+
+       LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+}
+
+EXPORT_SYMBOL(_down_write_nest_lock);
+
 void down_write_nested(struct rw_semaphore *sem, int subclass)
 {
        might_sleep();