X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fkernel%2Flocking%2Fmcs_spinlock.h;fp=kernel%2Fkernel%2Flocking%2Fmcs_spinlock.h;h=c835270f0c2f93c24f623e9ea2ba2e94eebb006a;hb=52f993b8e89487ec9ee15a7fb4979e0f09a45b27;hp=5b9102a47ea5209dd887b6dfbca16215b2bad922;hpb=c189ccac5702322ed843fe17057035b7222a59b6;p=kvmfornfv.git

diff --git a/kernel/kernel/locking/mcs_spinlock.h b/kernel/kernel/locking/mcs_spinlock.h
index 5b9102a47..c835270f0 100644
--- a/kernel/kernel/locking/mcs_spinlock.h
+++ b/kernel/kernel/locking/mcs_spinlock.h
@@ -67,7 +67,13 @@ void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
 	node->locked = 0;
 	node->next   = NULL;
 
-	prev = xchg_acquire(lock, node);
+	/*
+	 * We rely on the full barrier with global transitivity implied by the
+	 * below xchg() to order the initialization stores above against any
+	 * observation of @node. And to provide the ACQUIRE ordering associated
+	 * with a LOCK primitive.
+	 */
+	prev = xchg(lock, node);
 	if (likely(prev == NULL)) {
 		/*
 		 * Lock acquired, don't need to set node->locked to 1. Threads