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-rw-r--r--kernel/locking/mcs_spinlock.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
index 5b9102a47ea5..c835270f0c2f 100644
--- a/kernel/locking/mcs_spinlock.h
+++ b/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