| From 1980860e0c8299316cddaf0992dd9e1258ec9d88 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com> |
| Date: Tue, 8 Nov 2022 14:19:52 +0200 |
| Subject: serial: 8250: Flush DMA Rx on RLSI |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> |
| |
| commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream. |
| |
| Returning true from handle_rx_dma() without flushing DMA first creates |
| a data ordering hazard. If DMA Rx has handled any character at the |
| point when RLSI occurs, the non-DMA path handles any pending characters |
| jumping them ahead of those characters that are pending under DMA. |
| |
| Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> |
| Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
| Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/tty/serial/8250/8250_port.c | 3 +-- |
| 1 file changed, 1 insertion(+), 2 deletions(-) |
| |
| --- a/drivers/tty/serial/8250/8250_port.c |
| +++ b/drivers/tty/serial/8250/8250_port.c |
| @@ -1824,10 +1824,9 @@ static bool handle_rx_dma(struct uart_82 |
| if (!up->dma->rx_running) |
| break; |
| fallthrough; |
| + case UART_IIR_RLSI: |
| case UART_IIR_RX_TIMEOUT: |
| serial8250_rx_dma_flush(up); |
| - /* fall-through */ |
| - case UART_IIR_RLSI: |
| return true; |
| } |
| return up->dma->rx_dma(up); |
