These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / tile / lib / spinlock_64.c

diff --git a/kernel/arch/tile/lib/spinlock_64.c b/kernel/arch/tile/lib/spinlock_64.c
index d6fb958..c8d1f94 100644 (file)
--- a/kernel/arch/tile/lib/spinlock_64.c
+++ b/kernel/arch/tile/lib/spinlock_64.c
@@ -65,8 +65,17 @@ EXPORT_SYMBOL(arch_spin_trylock);
 void arch_spin_unlock_wait(arch_spinlock_t *lock)
 {
        u32 iterations = 0;
-       while (arch_spin_is_locked(lock))
+       u32 val = READ_ONCE(lock->lock);
+       u32 curr = arch_spin_current(val);
+
+       /* Return immediately if unlocked. */
+       if (arch_spin_next(val) == curr)
+               return;
+
+       /* Wait until the current locker has released the lock. */
+       do {
                delay_backoff(iterations++);
+       } while (arch_spin_current(READ_ONCE(lock->lock)) == curr);
 }
 EXPORT_SYMBOL(arch_spin_unlock_wait);