On Tue, Jun 28, 2022 at 12:01:28PM +0300, Ilpo Järvinen wrote:
> Accessing LSR requires port lock because it mutates lsr_saved_flags
> in serial_lsr_in().
Don't remember if I given or not (and why if not) the tag, so here it is:
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Fixes: 197eb5c416ff ("serial: 8250_dw: Use serial_lsr_in() in dw8250_handle_irq()")
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
>
> ---
> I'll resend the third patch later.
>
> drivers/tty/serial/8250/8250_dw.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index 167a691c7b19..f78b13db1b1e 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -266,7 +266,10 @@ static int dw8250_handle_irq(struct uart_port *p)
>
> /* Manually stop the Rx DMA transfer when acting as flow controller */
> if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) {
> + spin_lock_irqsave(&p->lock, flags);
> status = serial_lsr_in(up);
> + spin_unlock_irqrestore(&p->lock, flags);
> +
> if (status & (UART_LSR_DR | UART_LSR_BI)) {
> dw8250_writel_ext(p, RZN1_UART_RDMACR, 0);
> dw8250_writel_ext(p, DW_UART_DMASA, 1);
>
> --
> tg: (f55d2e4b0a47..) dw/use-spinlock (depends on: 8250/fix-stop_tx-race)
--
With Best Regards,
Andy Shevchenko
