elevator: Fix a race in elevator switching

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / block / deadline-iosched.c

diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index ba19a3afab7929cf3ff0857683ccaef40a007a77..20614a33236220d0e79d99a2cfaf99822327bc57 100644 (file)
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -337,13 +337,21 @@ static void deadline_exit_queue(struct elevator_queue *e)
 /*
  * initialize elevator private data (deadline_data).
  */
-static int deadline_init_queue(struct request_queue *q)
+static int deadline_init_queue(struct request_queue *q, struct elevator_type *e)
 {
        struct deadline_data *dd;
+       struct elevator_queue *eq;
+
+       eq = elevator_alloc(q, e);
+       if (!eq)
+               return -ENOMEM;
 
        dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node);
-       if (!dd)
+       if (!dd) {
+               kobject_put(&eq->kobj);
                return -ENOMEM;
+       }
+       eq->elevator_data = dd;
 
        INIT_LIST_HEAD(&dd->fifo_list[READ]);
        INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
@@ -355,7 +363,9 @@ static int deadline_init_queue(struct request_queue *q)
        dd->front_merges = 1;
        dd->fifo_batch = fifo_batch;
 
-       q->elevator->elevator_data = dd;
+       spin_lock_irq(q->queue_lock);
+       q->elevator = eq;
+       spin_unlock_irq(q->queue_lock);
        return 0;
 }