NBD doesn't work well with CFQ (or AS) schedulers, so let's default to something
else.

The two problems I have experienced with nbd and cfq are:
 
1) nbd hangs with cfq on RHEL 5 (2.6.18) -- this may well have been fixed
 
There's a similar debian bug that has been filed as well:
 
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=447638
 
2) nbd performs about 10% better (the last time I tested) with deadline 
vs. cfq (the overhead of cfq doesn't provide much advantage to nbd [not 
being a real disk], and you end up going through the I/O scheduler on 
the nbd server anyway, so it makes sense that deadline is better with nbd)
 
There have been posts to nbd-general mailing list about problems with 
cfq and nbd also.

Signed-Off-By: Paul Clements <paul.clements@steeleye.com>

--- ./drivers/block/nbd.c.max_nbd_killed	2008-02-07 16:46:24.000000000 -0500
+++ ./drivers/block/nbd.c	2008-02-08 16:13:01.000000000 -0500
@@ -667,6 +667,12 @@ static int __init nbd_init(void)
 			put_disk(disk);
 			goto out;
 		}
+		if (elevator_init(disk->queue, "deadline") != 0) {
+			if (elevator_init(disk->queue, "noop") != 0) {
+				put_disk(disk);
+				goto out;
+			}
+		}
 	}
 
 	if (register_blkdev(NBD_MAJOR, "nbd")) {