1 files changed, 16 insertions, 0 deletions

diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index fe5a3342e960..a89cf09a8268 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -184,3 +184,19 @@ void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
         call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu);
 }
 EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm);
+
+/*
+ * XXX: Temporary kludge to work around SCSI blk-mq stall.  Used only by
+ * block/blk-mq.c::blk_mq_freeze_queue().  Will be removed during v3.18
+ * devel cycle.  Do not use anywhere else.
+ */
+void __percpu_ref_kill_expedited(struct percpu_ref *ref)
+{
+        WARN_ONCE(ref->pcpu_count_ptr & PCPU_REF_DEAD,
+                  "percpu_ref_kill() called more than once on %pf!",
+                  ref->release);
+
+        ref->pcpu_count_ptr |= PCPU_REF_DEAD;
+        synchronize_sched_expedited();
+        percpu_ref_kill_rcu(&ref->rcu);
+}