Add rcu_read_ongoing() API to each urcu flavor

[urcu.git] / urcu / static / urcu-qsbr.h

diff --git a/urcu/static/urcu-qsbr.h b/urcu/static/urcu-qsbr.h
index f3149569b2a2e2573df57936673d82eaadf0e1d7..ea5e13adebd5fae0374a5ad81693dd6cf46436c2 100644 (file)
--- a/urcu/static/urcu-qsbr.h
+++ b/urcu/static/urcu-qsbr.h
@@ -62,6 +62,12 @@ extern "C" {
 #define rcu_assert(args...)
 #endif
 
+enum rcu_state {
+       RCU_READER_ACTIVE_CURRENT,
+       RCU_READER_ACTIVE_OLD,
+       RCU_READER_INACTIVE,
+};
+
 #ifdef DEBUG_YIELD
 #include <sched.h>
 #include <time.h>
@@ -149,12 +155,16 @@ static inline void wake_up_gp(void)
        }
 }
 
-static inline int rcu_gp_ongoing(unsigned long *ctr)
+static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
 {
        unsigned long v;
 
        v = CMM_LOAD_SHARED(*ctr);
-       return v && (v != rcu_gp_ctr);
+       if (!v)
+               return RCU_READER_INACTIVE;
+       if (v == rcu_gp_ctr)
+               return RCU_READER_ACTIVE_CURRENT;
+       return RCU_READER_ACTIVE_OLD;
 }
 
 /*
@@ -180,6 +190,18 @@ static inline void _rcu_read_unlock(void)
 {
 }
 
+/*
+ * Returns whether within a RCU read-side critical section.
+ *
+ * This function is less than 10 lines long.  The intent is that this
+ * function meets the 10-line criterion for LGPL, allowing this function
+ * to be invoked directly from non-LGPL code.
+ */
+static inline int _rcu_read_ongoing(void)
+{
+       return URCU_TLS(rcu_reader).ctr;
+}
+
 /*
  * This is a helper function for _rcu_quiescent_state().
  * The first cmm_smp_mb() ensures memory accesses in the prior read-side