X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fstatic%2Furcu-bp.h;h=6e52d84bafe84f75dfd45593a2b58cad6431bcd0;hp=0fcaa3aa272806aa9c8786c96b7675de4fcfddd3;hb=67ecffc0f530a7b5c4dd5111ea7dd3213da8eb91;hpb=a77f7d8228bcf1259f8c4121ce02d4763424d45a

diff --git a/urcu/static/urcu-bp.h b/urcu/static/urcu-bp.h
index 0fcaa3a..6e52d84 100644
--- a/urcu/static/urcu-bp.h
+++ b/urcu/static/urcu-bp.h
@@ -102,6 +102,16 @@ struct rcu_reader {
  */
 extern DECLARE_URCU_TLS(struct rcu_reader *, rcu_reader);
 
+extern int urcu_bp_has_sys_membarrier;
+
+static inline void urcu_bp_smp_mb_slave(void)
+{
+	if (caa_likely(urcu_bp_has_sys_membarrier))
+		cmm_barrier();
+	else
+		cmm_smp_mb();
+}
+
 static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
 {
 	unsigned long v;
@@ -131,7 +141,7 @@ static inline void _rcu_read_lock_update(unsigned long tmp)
 {
 	if (caa_likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
 		_CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp.ctr));
-		cmm_smp_mb();
+		urcu_bp_smp_mb_slave();
 	} else
 		_CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp + RCU_GP_COUNT);
 }
@@ -154,6 +164,7 @@ static inline void _rcu_read_lock(void)
 		rcu_bp_register(); /* If not yet registered. */
 	cmm_barrier();	/* Ensure the compiler does not reorder us with mutex */
 	tmp = URCU_TLS(rcu_reader)->ctr;
+	urcu_assert((tmp & RCU_GP_CTR_NEST_MASK) != RCU_GP_CTR_NEST_MASK);
 	_rcu_read_lock_update(tmp);
 }
 
@@ -164,11 +175,13 @@ static inline void _rcu_read_lock(void)
  */
 static inline void _rcu_read_unlock(void)
 {
-	/*
-	 * Finish using rcu before decrementing the pointer.
-	 */
-	cmm_smp_mb();
-	_CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, URCU_TLS(rcu_reader)->ctr - RCU_GP_COUNT);
+	unsigned long tmp;
+
+	tmp = URCU_TLS(rcu_reader)->ctr;
+	urcu_assert(tmp & RCU_GP_CTR_NEST_MASK);
+	/* Finish using rcu before decrementing the pointer. */
+	urcu_bp_smp_mb_slave();
+	_CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp - RCU_GP_COUNT);
 	cmm_barrier();	/* Ensure the compiler does not reorder us with mutex */
 }
 
@@ -186,7 +199,7 @@ static inline int _rcu_read_ongoing(void)
 	return URCU_TLS(rcu_reader)->ctr & RCU_GP_CTR_NEST_MASK;
 }
 
-#ifdef __cplusplus 
+#ifdef __cplusplus
 }
 #endif