[PATCH tip/core/rcu 71/88] rcu: Convert rnp->lock wrappers to macros for SRCU use

From: Paul E. McKenney
Date: Thu May 25 2017 - 18:04:35 EST


Use of smp_mb__after_unlock_lock() would allow SRCU to omit a full
memory barrier during callback execution, so this commit converts
raw_spin_lock_rcu_node() from inline functions to type-generic macros
to allow them to handle locks in srcu_node structures as well as
rcu_node structures.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.h | 47 +++++++++++++++++++++--------------------------
1 file changed, 21 insertions(+), 26 deletions(-)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index ddfa34d020ba..a7f63f1074b4 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -580,27 +580,22 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
* As ->lock of struct rcu_node is a __private field, therefore one should use
* these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
*/
-static inline void raw_spin_lock_rcu_node(struct rcu_node *rnp)
-{
- raw_spin_lock(&ACCESS_PRIVATE(rnp, lock));
- smp_mb__after_unlock_lock();
-}
+#define raw_spin_lock_rcu_node(p) \
+do { \
+ raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
+ smp_mb__after_unlock_lock(); \
+} while (0)

-static inline void raw_spin_unlock_rcu_node(struct rcu_node *rnp)
-{
- raw_spin_unlock(&ACCESS_PRIVATE(rnp, lock));
-}
+#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock))

-static inline void raw_spin_lock_irq_rcu_node(struct rcu_node *rnp)
-{
- raw_spin_lock_irq(&ACCESS_PRIVATE(rnp, lock));
- smp_mb__after_unlock_lock();
-}
+#define raw_spin_lock_irq_rcu_node(p) \
+do { \
+ raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
+ smp_mb__after_unlock_lock(); \
+} while (0)

-static inline void raw_spin_unlock_irq_rcu_node(struct rcu_node *rnp)
-{
- raw_spin_unlock_irq(&ACCESS_PRIVATE(rnp, lock));
-}
+#define raw_spin_unlock_irq_rcu_node(p) \
+ raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock))

#define raw_spin_lock_irqsave_rcu_node(rnp, flags) \
do { \
@@ -615,11 +610,11 @@ do { \
raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(rnp, lock), flags); \
} while (0)

-static inline bool raw_spin_trylock_rcu_node(struct rcu_node *rnp)
-{
- bool locked = raw_spin_trylock(&ACCESS_PRIVATE(rnp, lock));
-
- if (locked)
- smp_mb__after_unlock_lock();
- return locked;
-}
+#define raw_spin_trylock_rcu_node(p) \
+({ \
+ bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
+ \
+ if (___locked) \
+ smp_mb__after_unlock_lock(); \
+ ___locked; \
+})
--
2.5.2