TTY: switch tty_flip_buffer_push

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 1bfe97a..b6efaca 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -544,7 +544,7 @@
 
 /**
  *	tty_flip_buffer_push	-	terminal
- *	@tty: tty to push
+ *	@port: tty port to push
  *
  *	Queue a push of the terminal flip buffers to the line discipline. This
  *	function must not be called from IRQ context if port->low_latency is
@@ -556,9 +556,9 @@
  *	Locking: tty buffer lock. Driver locks in low latency mode.
  */
 
-void tty_flip_buffer_push(struct tty_struct *tty)
+void tty_flip_buffer_push(struct tty_port *port)
 {
-	struct tty_bufhead *buf = &tty->port->buf;
+	struct tty_bufhead *buf = &port->buf;
 	unsigned long flags;
 
 	spin_lock_irqsave(&buf->lock, flags);
@@ -566,7 +566,7 @@
 		buf->tail->commit = buf->tail->used;
 	spin_unlock_irqrestore(&buf->lock, flags);
 
-	if (tty->port->low_latency)
+	if (port->low_latency)
 		flush_to_ldisc(&buf->work);
 	else
 		schedule_work(&buf->work);