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/bfin_uart.c b/drivers/tty/serial/bfin_uart.c
index 2e2b2c1..12dceda 100644
--- a/drivers/tty/serial/bfin_uart.c
+++ b/drivers/tty/serial/bfin_uart.c
@@ -223,7 +223,6 @@
 #ifdef CONFIG_SERIAL_BFIN_PIO
 static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 {
-	struct tty_struct *tty = NULL;
 	unsigned int status, ch, flg;
 	static struct timeval anomaly_start = { .tv_sec = 0 };
 
@@ -242,11 +241,9 @@
 			return;
 		}
 
-	if (!uart->port.state || !uart->port.state->port.tty)
+	if (!uart->port.state)
 		return;
 #endif
-	tty = uart->port.state->port.tty;
-
 	if (ANOMALY_05000363) {
 		/* The BF533 (and BF561) family of processors have a nice anomaly
 		 * where they continuously generate characters for a "single" break.
@@ -325,7 +322,7 @@
 	uart_insert_char(&uart->port, status, OE, ch, flg);
 
  ignore_char:
-	tty_flip_buffer_push(tty);
+	tty_flip_buffer_push(&uart->port.state->port);
 }
 
 static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
@@ -426,7 +423,6 @@
 
 static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
 {
-	struct tty_struct *tty = uart->port.state->port.tty;
 	int i, flg, status;
 
 	status = UART_GET_LSR(uart);
@@ -471,7 +467,7 @@
 	}
 
  dma_ignore_char:
-	tty_flip_buffer_push(tty);
+	tty_flip_buffer_push(&uart->port.state->port);
 }
 
 void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)