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/lpc32xx_hs.c b/drivers/tty/serial/lpc32xx_hs.c
index 5cd1805..c8448e6 100644
--- a/drivers/tty/serial/lpc32xx_hs.c
+++ b/drivers/tty/serial/lpc32xx_hs.c
@@ -259,16 +259,6 @@
 {
 	struct tty_port *tport = &port->state->port;
 	unsigned int tmp, flag;
-	struct tty_struct *tty = tty_port_tty_get(tport);
-
-	if (!tty) {
-		/* Discard data: no tty available */
-		while (!(readl(LPC32XX_HSUART_FIFO(port->membase)) &
-			 LPC32XX_HSU_RX_EMPTY))
-			;
-
-		return;
-	}
 
 	/* Read data from FIFO and push into terminal */
 	tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
@@ -289,8 +279,7 @@
 
 		tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
 	}
-	tty_flip_buffer_push(tty);
-	tty_kref_put(tty);
+	tty_flip_buffer_push(tport);
 }
 
 static void __serial_lpc32xx_tx(struct uart_port *port)
@@ -367,8 +356,7 @@
 	/* Data received? */
 	if (status & (LPC32XX_HSU_RX_TIMEOUT_INT | LPC32XX_HSU_RX_TRIG_INT)) {
 		__serial_lpc32xx_rx(port);
-		if (tty)
-			tty_flip_buffer_push(tty);
+		tty_flip_buffer_push(tport);
 	}
 
 	/* Transmit data request? */