X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=urcu-qsbr.c;h=d1f5d91846af8f8098eacab85a588d945ab9873f;hb=0a1d290b4432036a7c1bf4a1b251ec9086036a87;hp=300eb970e17f5031be51d4421a1e4a3a0080cd38;hpb=7ac06cef7a7d9394332837edc5c0e9595286a5fc;p=urcu.git

diff --git a/urcu-qsbr.c b/urcu-qsbr.c
index 300eb97..d1f5d91 100644
--- a/urcu-qsbr.c
+++ b/urcu-qsbr.c
@@ -55,7 +55,6 @@ long __thread rcu_reader_qs_gp;
 struct reader_registry {
 	pthread_t tid;
 	long *rcu_reader_qs_gp;
-	char *need_mb;
 };
 
 #ifdef DEBUG_YIELD
@@ -64,10 +63,9 @@ unsigned int __thread rand_yield;
 #endif
 
 static struct reader_registry *registry;
-static char __thread need_mb;
 static int num_readers, alloc_readers;
 
-void internal_urcu_lock(void)
+static void internal_urcu_lock(void)
 {
 	int ret;
 
@@ -84,17 +82,12 @@ void internal_urcu_lock(void)
 			perror("Error in pthread mutex lock");
 			exit(-1);
 		}
-		if (need_mb) {
-			smp_mb();
-			need_mb = 0;
-			smp_mb();
-		}
 		poll(NULL,0,10);
 	}
 #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
 }
 
-void internal_urcu_unlock(void)
+static void internal_urcu_unlock(void)
 {
 	int ret;
 
@@ -117,7 +110,7 @@ static void force_mb_all_threads(void)
 	smp_mb();
 }
 
-void wait_for_quiescent_state(void)
+static void wait_for_quiescent_state(void)
 {
 	struct reader_registry *index;
 
@@ -152,12 +145,27 @@ 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();
 }
 
 /*
@@ -237,7 +245,6 @@ static void rcu_add_reader(pthread_t id)
 	registry[num_readers].tid = id;
 	/* reference to the TLS of _this_ reader thread. */
 	registry[num_readers].rcu_reader_qs_gp = &rcu_reader_qs_gp;
-	registry[num_readers].need_mb = &need_mb;
 	num_readers++;
 }