elevator: check for ELEVATOR_INSERT_SORT_MERGE in !elvpriv case too
Jens Axboe [Thu, 21 Apr 2011 17:28:35 +0000 (19:28 +0200)]
The sort insert is the one that goes to the IO scheduler. With
the SORT_MERGE addition, we could bypass IO scheduler setup
but still ask the IO scheduler to insert the request. This would
cause an oops on switching IO schedulers through the sysfs
interface, unless the disk just happened to be idle while it
occured.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block/elevator.c

index 6f6abc0..45ca1e3 100644 (file)
@@ -671,7 +671,8 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
                        q->boundary_rq = rq;
                }
        } else if (!(rq->cmd_flags & REQ_ELVPRIV) &&
-                   where == ELEVATOR_INSERT_SORT)
+                   (where == ELEVATOR_INSERT_SORT ||
+                    where == ELEVATOR_INSERT_SORT_MERGE))
                where = ELEVATOR_INSERT_BACK;
 
        switch (where) {