+/*
+ * On a system with shared processors (that is, where a physical
+ * processor is multiplexed between several virtual processors),
+ * there is no point spinning on a lock if the holder of the lock
+ * isn't currently scheduled on a physical processor. Instead
+ * we detect this situation and ask the hypervisor to give the
+ * rest of our timeslice to the lock holder.
+ *
+ * So that we can tell which virtual processor is holding a lock,
+ * we put 0x80000000 | smp_processor_id() in the lock when it is
+ * held. Conveniently, we have a word in the paca that holds this
+ * value.
+ */
+
+#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
+/* We only yield to the hypervisor if we are in shared processor mode */
+#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
+extern void __spin_yield(spinlock_t *lock);
+extern void __rw_yield(rwlock_t *lock);
+#else /* SPLPAR || ISERIES */
+#define __spin_yield(x) barrier()
+#define __rw_yield(x) barrier()
+#define SHARED_PROCESSOR 0
+#endif
+extern void spin_unlock_wait(spinlock_t *lock);
+
+/*
+ * This returns the old value in the lock, so we succeeded
+ * in getting the lock if the return value is 0.
+ */
+static __inline__ unsigned long __spin_trylock(spinlock_t *lock)