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/serial/ioc3_serial.c b/drivers/tty/serial/ioc3_serial.c
index edbdc4e..6e4c715 100644
--- a/drivers/tty/serial/ioc3_serial.c
+++ b/drivers/tty/serial/ioc3_serial.c
@@ -1393,7 +1393,6 @@
  */
 static int receive_chars(struct uart_port *the_port)
 {
-	struct tty_struct *tty;
 	unsigned char ch[MAX_CHARS];
 	int read_count = 0, read_room, flip = 0;
 	struct uart_state *state = the_port->state;
@@ -1403,14 +1402,11 @@
 	/* Make sure all the pointers are "good" ones */
 	if (!state)
 		return 0;
-	if (!state->port.tty)
-		return 0;
 
 	if (!(port->ip_flags & INPUT_ENABLE))
 		return 0;
 
 	spin_lock_irqsave(&the_port->lock, pflags);
-	tty = state->port.tty;
 
 	read_count = do_read(the_port, ch, MAX_CHARS);
 	if (read_count > 0) {
@@ -1422,7 +1418,7 @@
 	spin_unlock_irqrestore(&the_port->lock, pflags);
 
 	if (flip)
-		tty_flip_buffer_push(tty);
+		tty_flip_buffer_push(&state->port);
 
 	return read_count;
 }