locking/spinlock, arch: Update and fix spin_unlock_wait() implementations

[cascardo/linux.git] / arch / tile / lib / spinlock_64.c

diff --git a/arch/tile/lib/spinlock_64.c b/arch/tile/lib/spinlock_64.c
index c8d1f94..a4b5b2c 100644 (file)
--- a/arch/tile/lib/spinlock_64.c
+++ b/arch/tile/lib/spinlock_64.c
@@ -76,6 +76,12 @@ void arch_spin_unlock_wait(arch_spinlock_t *lock)
        do {
                delay_backoff(iterations++);
        } while (arch_spin_current(READ_ONCE(lock->lock)) == curr);
+
+       /*
+        * The TILE architecture doesn't do read speculation; therefore
+        * a control dependency guarantees a LOAD->{LOAD,STORE} order.
+        */
+       barrier();
 }
 EXPORT_SYMBOL(arch_spin_unlock_wait);