From: Jens Axboe <axboe@suse.de>

This one-liner should make writing to /sys/block/<dev>/queue/scheduler fail
with -EINVAL if the specified elevator doesn't exist.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 25-akpm/drivers/block/elevator.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN drivers/block/elevator.c~return-einval-on-elevator_store-failure drivers/block/elevator.c
--- 25/drivers/block/elevator.c~return-einval-on-elevator_store-failure	2004-10-03 16:36:38.269363432 -0700
+++ 25-akpm/drivers/block/elevator.c	2004-10-03 16:36:50.001579864 -0700
@@ -566,7 +566,7 @@ ssize_t elv_iosched_store(request_queue_
 	e = elevator_find(elevator_name);
 	if (!e) {
 		printk("elevator: type %s not found\n", elevator_name);
-		return count;
+		return -EINVAL;
 	}
 
 	elevator_switch(q, e);
_