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/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
index bdf67b0..de14bd7 100644
--- a/drivers/tty/serial/efm32-uart.c
+++ b/drivers/tty/serial/efm32-uart.c
@@ -249,12 +249,9 @@
 	int handled = IRQ_NONE;
 	struct uart_port *port = &efm_port->port;
 	struct tty_port *tport = &port->state->port;
-	struct tty_struct *tty;
 
 	spin_lock(&port->lock);
 
-	tty = tty_kref_get(tport->tty);
-
 	if (irqflag & UARTn_IF_RXDATAV) {
 		efm32_uart_write32(efm_port, UARTn_IF_RXDATAV, UARTn_IFC);
 		efm32_uart_rx_chars(efm_port);
@@ -270,10 +267,7 @@
 		handled = IRQ_HANDLED;
 	}
 
-	if (tty) {
-		tty_flip_buffer_push(tty);
-		tty_kref_put(tty);
-	}
+	tty_flip_buffer_push(tport);
 
 	spin_unlock(&port->lock);