elevator: check for ELEVATOR_INSERT_SORT_MERGE in !elvpriv case too

Jens Axboe · Jens Axboe · commit 3aa72873ffdc · 2011-04-21T19:28:35.000+02:00
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 &lt;jaxboe@fusionio.com&gt;
diff --git a/block/elevator.c b/block/elevator.c
@@ -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) {

Original file line number	Diff line number	Diff line change
`@@ -671,7 +671,8 @@ void __elv_add_request(struct request_queue q, struct request rq, int where)`
`671`	`671`	`q->boundary_rq = rq;`
`672`	`672`	`}`
`673`	`673`	`} else if (!(rq->cmd_flags & REQ_ELVPRIV) &&`
`674`		`- where == ELEVATOR_INSERT_SORT)`
	`674`	`+ (where == ELEVATOR_INSERT_SORT \|\|`
	`675`	`+ where == ELEVATOR_INSERT_SORT_MERGE))`
`675`	`676`	`where = ELEVATOR_INSERT_BACK;`
`676`	`677`
`677`	`678`	`switch (where) {`