diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c
index 564172234819..c6744ff38294 100644
--- a/drivers/block/as-iosched.c
+++ b/drivers/block/as-iosched.c
@@ -1973,8 +1973,8 @@ static int __init as_init(void)
 
 static void __exit as_exit(void)
 {
-	kmem_cache_destroy(arq_pool);
 	elv_unregister(&iosched_as);
+	kmem_cache_destroy(arq_pool);
 }
 
 module_init(as_init);
diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c
index 94690e4d41e0..5281f8e70510 100644
--- a/drivers/block/cfq-iosched.c
+++ b/drivers/block/cfq-iosched.c
@@ -2418,28 +2418,8 @@ static int __init cfq_init(void)
 
 static void __exit cfq_exit(void)
 {
-	struct task_struct *g, *p;
-	unsigned long flags;
-
-	read_lock_irqsave(&tasklist_lock, flags);
-
-	/*
-	 * iterate each process in the system, removing our io_context
-	 */
-	do_each_thread(g, p) {
-		struct io_context *ioc = p->io_context;
-
-		if (ioc && ioc->cic) {
-			ioc->cic->exit(ioc->cic);
-			cfq_free_io_context(ioc->cic);
-			ioc->cic = NULL;
-		}
-	} while_each_thread(g, p);
-
-	read_unlock_irqrestore(&tasklist_lock, flags);
-
-	cfq_slab_kill();
 	elv_unregister(&iosched_cfq);
+	cfq_slab_kill();
 }
 
 module_init(cfq_init);
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 55621d5c5774..58e881bfd189 100644
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -642,6 +642,27 @@ EXPORT_SYMBOL_GPL(elv_register);
 
 void elv_unregister(struct elevator_type *e)
 {
+	struct task_struct *g, *p;
+
+	/*
+	 * Iterate every thread in the process to remove the io contexts.
+	 */
+	read_lock(&tasklist_lock);
+	do_each_thread(g, p) {
+		struct io_context *ioc = p->io_context;
+		if (ioc && ioc->cic) {
+			ioc->cic->exit(ioc->cic);
+			ioc->cic->dtor(ioc->cic);
+			ioc->cic = NULL;
+		}
+		if (ioc && ioc->aic) {
+			ioc->aic->exit(ioc->aic);
+			ioc->aic->dtor(ioc->aic);
+			ioc->aic = NULL;
+		}
+	} while_each_thread(g, p);
+	read_unlock(&tasklist_lock);
+
 	spin_lock_irq(&elv_list_lock);
 	list_del_init(&e->list);
 	spin_unlock_irq(&elv_list_lock);