rcupdate: Replace smp_read_barrier_depends() with lockless_dereference()

Recently lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends(). The following PATCH makes the change.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.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 ed4f593..386ba28 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -582,11 +582,11 @@ static inline void rcu_preempt_sleep_check(void)
 })
 #define __rcu_dereference_check(p, c, space) \
 ({ \
-       typeof(*p) *_________p1 = (typeof(*p) *__force)ACCESS_ONCE(p); \
+       /* Dependency order vs. p above. */ \
+       typeof(*p) *________p1 = (typeof(*p) *__force)lockless_dereference(p); \
        rcu_lockdep_assert(c, "suspicious rcu_dereference_check() usage"); \
        rcu_dereference_sparse(p, space); \
-       smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
-       ((typeof(*p) __force __kernel *)(_________p1)); \
+       ((typeof(*p) __force __kernel *)(________p1)); \
 })
 #define __rcu_dereference_protected(p, c, space) \
 ({ \
@@ -603,10 +603,10 @@ static inline void rcu_preempt_sleep_check(void)
 })
 #define __rcu_dereference_index_check(p, c) \
 ({ \
-       typeof(p) _________p1 = ACCESS_ONCE(p); \
+       /* Dependency order vs. p above. */ \
+       typeof(p) _________p1 = lockless_dereference(p); \
        rcu_lockdep_assert(c, \
                           "suspicious rcu_dereference_index_check() usage"); \
-       smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
        (_________p1); \
 })