block: request_module(): use format string

Avoid bad things happening if the module has a printk control string in
its name.

Signed-off-by: maximilian attems <max@stro.at>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/elevator.c b/block/elevator.c
index 1f5bfe6..ed6f8f3 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -150,7 +150,7 @@
 		else
 			sprintf(elv, "%s-iosched", name);
 
-		request_module(elv);
+		request_module("%s", elv);
 		spin_lock(&elv_list_lock);
 		e = elevator_find(name);
 	}