update README

[urcu.git] / urcu-qsbr.c

diff --git a/urcu-qsbr.c b/urcu-qsbr.c
index 14733ab21e1b61d10bf93ecc082967cdf9d717cd..d1f5d91846af8f8098eacab85a588d945ab9873f 100644 (file)
--- a/urcu-qsbr.c
+++ b/urcu-qsbr.c
@@ -145,12 +145,27 @@ static void wait_for_quiescent_state(void)
 
 void synchronize_rcu(void)
 {
+       int was_online;
+
+       was_online = rcu_reader_qs_gp & 1;
+
+       /*
+        * Mark the writer thread offline to make sure we don't wait for
+        * our own quiescent state. This allows using synchronize_rcu() in
+        * threads registered as readers.
+        */
+       if (was_online)
+               _rcu_thread_offline();
+
        internal_urcu_lock();
        force_mb_all_threads();
        urcu_gp_ctr += 2;
        wait_for_quiescent_state();
        force_mb_all_threads();
        internal_urcu_unlock();
+
+       if (was_online)
+               _rcu_thread_online();
 }
 
 /*