24ec839c causes this:

WARNING: "get_current_tty" [drivers/s390/char/fs3270.ko] undefined!

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>