[PATCH] block: return NULL if request_module() failed in elevator_get()

[Chengguang Xu]

If request_module() failed then it seems no reason to lookup
the iosched again, so add a check to handle this case.

Signed-off-by: Chengguang Xu <cgxu...@gmx.com>
---
 block/elevator.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/elevator.c b/block/elevator.c
index 8fdcd64ae12e..f89527951243 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -124,7 +124,9 @@ static struct elevator_type *elevator_get(struct 
request_queue *q,
        e = elevator_find(name, q->mq_ops != NULL);
        if (!e && try_loading) {
                spin_unlock(&elv_list_lock);
-               request_module("%s-iosched", name);
+               if (request_module("%s-iosched", name))
+                       return e;
+
                spin_lock(&elv_list_lock);
                e = elevator_find(name, q->mq_ops != NULL);
        }
-- 
2.17.2