[PATCH net-next 2/7] rcu: un-hide lockdep maps for !LOCKDEP

Jakub Kicinski
2020-09-16T18:48:28Z

We're trying to make LOCKDEP-related forward declarations
visible to the compiler and depend on dead code elimination
to remove them.

Expose RCU lock maps.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: paulmck@kernel.org
CC: josh@joshtriplett.org
CC: rostedt@goodmis.org
CC: mathieu.desnoyers@efficios.com
CC: joel@joelfernandes.org
CC: jiangshanlai@gmail.com
---
include/linux/rcupdate.h | 9 +++++----
include/linux/rcupdate_trace.h | 4 ++--
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d15d46db61f7..53f9648cb982 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -234,6 +234,11 @@ bool rcu_lockdep_current_cpu_online(void);
static inline bool rcu_lockdep_current_cpu_online(void) { return true; }
#endif /* #else #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */

+extern struct lockdep_map rcu_lock_map;
+extern struct lockdep_map rcu_bh_lock_map;
+extern struct lockdep_map rcu_sched_lock_map;
+extern struct lockdep_map rcu_callback_map;
+
#ifdef CONFIG_DEBUG_LOCK_ALLOC

static inline void rcu_lock_acquire(struct lockdep_map *map)
@@ -246,10 +251,6 @@ static inline void rcu_lock_release(struct lockdep_map *map)
lock_release(map, _THIS_IP_);
}

-extern struct lockdep_map rcu_lock_map;
-extern struct lockdep_map rcu_bh_lock_map;
-extern struct lockdep_map rcu_sched_lock_map;
-extern struct lockdep_map rcu_callback_map;
int debug_lockdep_rcu_enabled(void);
int rcu_read_lock_held(void);
int rcu_read_lock_bh_held(void);
diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h
index aaaac8ac927c..25cdef506cae 100644
--- a/include/linux/rcupdate_trace.h
+++ b/include/linux/rcupdate_trace.h
@@ -11,10 +11,10 @@
#include <linux/sched.h>
#include <linux/rcupdate.h>

-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-
extern struct lockdep_map rcu_trace_lock_map;

+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
static inline int rcu_read_lock_trace_held(void)
{
return lock_is_held(&rcu_trace_lock_map);
--
2.26.2