[PATCH] uml: avoid using elv_queue_empty

[PATCH] uml: avoid using elv_queue_empty

Avoid using, in the UBD driver, the elv_queue_empty function.  It's for the
block layer only; in fact, the Anticipatory Scheduler can return NULL with
elv_next_request() even if the queue is not empty, because it waits for the
process to send another request before seeking on the disk.

In fact, if (with uml-ubd-any-elevator) we let UBD use any scheduler,
elevator=as will make the UBD driver Oops, if we don't have this patch.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>