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    SubjectRe: [PATCH 3.10 219/268] tty/serial: atmel: fix race condition (TX+DMA)
    Hi Willy,

    You can drop this patch.

    There's nothing to fix on 3.10.x since the DMA TX support has been
    introduced in 3.12.

    Thanks !


    2017-06-19 20:31 GMT+02:00 Willy Tarreau <w@1wt.eu>:
    > From: Richard Genoud <richard.genoud@gmail.com>
    >
    > commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream.
    >
    > If uart_flush_buffer() is called between atmel_tx_dma() and
    > atmel_complete_tx_dma(), the circular buffer has been cleared, but not
    > atmel_port->tx_len.
    > That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE -
    > atmel_port->tx_len) bytes).
    >
    > Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com>
    > [rg] backport to 3.12
    > Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
    > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    > Signed-off-by: Willy Tarreau <w@1wt.eu>
    > ---
    > drivers/tty/serial/atmel_serial.c | 5 +++++
    > 1 file changed, 5 insertions(+)
    >
    > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
    > index 82127ac..41d1df5 100644
    > --- a/drivers/tty/serial/atmel_serial.c
    > +++ b/drivers/tty/serial/atmel_serial.c
    > @@ -1090,6 +1090,11 @@ static void atmel_flush_buffer(struct uart_port *port)
    > UART_PUT_TCR(port, 0);
    > atmel_port->pdc_tx.ofs = 0;
    > }
    > + /*
    > + * in uart_flush_buffer(), the xmit circular buffer has just
    > + * been cleared, so we have to reset its length accordingly.
    > + */
    > + sg_dma_len(&atmel_port->sg_tx) = 0;
    > }
    >
    > /*
    > --
    > 2.8.0.rc2.1.gbe9624a
    >

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