X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=c6d7dbc9d83a011a7b7d2885f93460a268da6ea2;hp=bb6629c718086a9800a22a4d3ab21685b27c26a5;hb=d40fde2c4f6170c3ace770354d99acc9e9732ec5;hpb=935b11ff4cf9053954d21b9d63c4ee367b12a652

diff --git a/urcu.c b/urcu.c
index bb6629c..c6d7dbc 100644
--- a/urcu.c
+++ b/urcu.c
@@ -208,16 +208,14 @@ void update_counter_and_wait(void)
 	STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE);
 
 	/*
-	 * Must commit qparity update to memory before waiting for other parity
-	 * quiescent state. Failure to do so could result in the writer waiting
-	 * forever while new readers are always accessing data (no progress).
-	 * Ensured by STORE_SHARED and LOAD_SHARED.
+	 * Must commit rcu_gp_ctr update to memory before waiting for quiescent
+	 * state. Failure to do so could result in the writer waiting forever
+	 * while new readers are always accessing data (no progress). Enforce
+	 * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr.
 	 */
+	barrier();
 
 	/*
-	 * Enforce compiler-order of store to rcu_gp_ctr before before
-	 * load rcu_reader ctr.
-	 * This ensures synchronize_rcu() cannot be starved by readers.
 	 *
 	 * Adding a smp_mb() which is _not_ formally required, but makes the
 	 * model easier to understand. It does not have a big performance impact
@@ -306,11 +304,12 @@ void synchronize_rcu(void)
 
 	/*
 	 * Must finish waiting for quiescent state for parity 0 before
-	 * committing qparity update to memory. Failure to do so could result in
-	 * the writer waiting forever while new readers are always accessing
-	 * data (no progress).
-	 * Ensured by STORE_SHARED and LOAD_SHARED.
+	 * committing next rcu_gp_ctr update to memory. Failure to do so could
+	 * result in the writer waiting forever while new readers are always
+	 * accessing data (no progress).  Enforce compiler-order of load
+	 * rcu_reader ctr before store to rcu_gp_ctr.
 	 */
+	barrier();
 
 	/*
 	 * Adding a smp_mb() which is _not_ formally required, but makes the