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.

Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
---
 drivers/tty/serial/8250/8250_omap.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_omap.c 
b/drivers/tty/serial/8250/8250_omap.c
index 2ac63c8bd946..933f7ef2c004 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -738,6 +738,7 @@ 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);
@@ -753,8 +754,10 @@ 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);
 
-- 
2.5.0

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