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>

1 files changed, 2 insertions, 17 deletions

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 967f1cb311f3..8b40a1fc9681 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -593,17 +593,9 @@ static int push_rx(struct eg20t_port *priv, const unsigned char *buf,
 {
         struct uart_port *port = &priv->port;
         struct tty_port *tport = &port->state->port;
-        struct tty_struct *tty;
-
-        tty = tty_port_tty_get(tport);
-        if (!tty) {
-                dev_dbg(priv->port.dev, "%s:tty is busy now", __func__);
-                return -EBUSY;
-        }
 
         tty_insert_flip_string(tport, buf, size);
-        tty_flip_buffer_push(tty);
-        tty_kref_put(tty);
+        tty_flip_buffer_push(tport);
 
         return 0;
 }
@@ -744,19 +736,12 @@ static void pch_dma_rx_complete(void *arg)
 {
         struct eg20t_port *priv = arg;
         struct uart_port *port = &priv->port;
-        struct tty_struct *tty = tty_port_tty_get(&port->state->port);
         int count;
 
-        if (!tty) {
-                dev_dbg(priv->port.dev, "%s:tty is busy now", __func__);
-                return;
-        }
-
         dma_sync_sg_for_cpu(port->dev, &priv->sg_rx, 1, DMA_FROM_DEVICE);
         count = dma_push_rx(priv, priv->trigger_level);
         if (count)
-                tty_flip_buffer_push(tty);
-        tty_kref_put(tty);
+                tty_flip_buffer_push(&port->state->port);
         async_tx_ack(priv->desc_rx);
         pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT |
                                             PCH_UART_HAL_RX_ERR_INT);