rcu: Warn when rcu_read_lock() is used in extended quiescent state

We are currently able to detect uses of rcu_dereference_check() inside
extended quiescent states (such as dyntick-idle mode). But rcu_read_lock()
and friends can be used without rcu_dereference(), so that the earlier
commit checking for use of rcu_dereference() and friends while in
dyntick-idle mode miss some error conditions.  This commit therefore adds
dyntick-idle checking to rcu_read_lock() and friends.

Uses of RCU from within dyntick-idle mode are totally ignored by
RCU, hence the importance of these checks.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 7d8fa7cd32bc6b2f2df07bce4b2bf2a4b1940271..a9bc36d522c47f999650c11dd2d06b38e55ee5dc 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -243,21 +243,53 @@ static inline bool rcu_check_extended_qs(void) { return false; }
 
 #define PROVE_RCU(a) a
 
+static inline void rcu_lock_acquire(struct lockdep_map *map)
+{
+       WARN_ON_ONCE(rcu_check_extended_qs());
+       lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);
+}
+
+static inline void rcu_lock_release(struct lockdep_map *map)
+{
+       WARN_ON_ONCE(rcu_check_extended_qs());
+       lock_release(map, 1, _THIS_IP_);
+}
+
 extern struct lockdep_map rcu_lock_map;
-# define rcu_read_acquire() \
-               lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release()    lock_release(&rcu_lock_map, 1, _THIS_IP_)
+
+static inline void rcu_read_acquire(void)
+{
+       rcu_lock_acquire(&rcu_lock_map);
+}
+
+static inline void rcu_read_release(void)
+{
+       rcu_lock_release(&rcu_lock_map);
+}
 
 extern struct lockdep_map rcu_bh_lock_map;
-# define rcu_read_acquire_bh() \
-               lock_acquire(&rcu_bh_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release_bh() lock_release(&rcu_bh_lock_map, 1, _THIS_IP_)
+
+static inline void rcu_read_acquire_bh(void)
+{
+       rcu_lock_acquire(&rcu_bh_lock_map);
+}
+
+static inline void rcu_read_release_bh(void)
+{
+       rcu_lock_release(&rcu_bh_lock_map);
+}
 
 extern struct lockdep_map rcu_sched_lock_map;
-# define rcu_read_acquire_sched() \
-               lock_acquire(&rcu_sched_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release_sched() \
-               lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
+
+static inline void rcu_read_acquire_sched(void)
+{
+       rcu_lock_acquire(&rcu_sched_lock_map);
+}
+
+static inline void rcu_read_release_sched(void)
+{
+       rcu_lock_release(&rcu_sched_lock_map);
+}
 
 extern int debug_lockdep_rcu_enabled(void);