serial: 8250_omap: check how many bytes were injected

The function tty_insert_flip_string() returns an int and as such it
might fail. So the result is that I kindly asked to insert 48 bytes and
the function only insterted 32.
I have no idea what to do with the remaining 16 so I think dropping them
is the only option. I also increase the buf_overrun counter so userpace
has a clue that we lost bytes.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 826c5c4a2103be3ac9c5065eeb8274fd8ce8c75f..6efe4dd6e77ad73599396c6343b8efcc9efbfdce 100644 (file)
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -726,6 +726,7 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
        struct dma_tx_state     state;
        int                     count;
        unsigned long           flags;
+       int                     ret;
 
        dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
                                dma->rx_size, DMA_FROM_DEVICE);
@@ -741,8 +742,10 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
 
        count = dma->rx_size - state.residue;
 
-       tty_insert_flip_string(tty_port, dma->rx_buf, count);
-       p->port.icount.rx += count;
+       ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
+
+       p->port.icount.rx += ret;
+       p->port.icount.buf_overrun += count - ret;
 unlock:
        spin_unlock_irqrestore(&priv->rx_dma_lock, flags);