[PATCH] s390: fix build failure in con3215.c tty wakeup tasklet

[Paul Gortmaker <paul.gortmaker@windriver.com>]

Commit 86b26007a37d81e7aca242bb5b649473f8f81297 (tty-next)

    "TTY: con3215, use tty from tty_port"

removed the tty struct from the raw struct, causing:

  CC      drivers/s390/char/con3215.o
drivers/s390/char/con3215.c: In function 'raw3215_wakeup':
drivers/s390/char/con3215.c:339:16: error: 'struct raw3215_info' has no member named 'tty'
make[2]: *** [drivers/s390/char/con3215.o] Error 1

We can't simply add a tty to the args of raw3215_wakeup since
it is registered as a tasklet.  The flow is:

	raw3215_irq
		--> tty_port_tty_get
			--> raw3215_next_io
				--> tasklet_schedule
		--> tty_kref_put

so it seems we'll need to do a get/put in the raw3215_wakeup
tasklet as well.

Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index e928e04..759c43c 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -336,7 +336,13 @@ static inline void raw3215_try_io(struct raw3215_info *raw)
 static void raw3215_wakeup(unsigned long data)
 {
 	struct raw3215_info *raw = (struct raw3215_info *) data;
-	tty_wakeup(raw->tty);
+	struct tty_struct *tty = tty_port_tty_get(&raw->port);
+
+	if (tty == NULL)
+		return;
+
+	tty_wakeup(tty);
+	tty_kref_put(tty);
 }
 
 /*
-- 
1.7.9.1