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: [PATCH] serial: 8250: Flush DMA Rx on RLSI
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Git-commit: 1980860e0c8299316cddaf0992dd9e1258ec9d88
Patch-mainline: v6.1-rc6
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/tty/serial/8250/8250_port.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 92dd18716169..388172289627 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1901,10 +1901,9 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
if (!up->dma->rx_running)
break;
fallthrough;
+ case UART_IIR_RLSI:
case UART_IIR_RX_TIMEOUT:
serial8250_rx_dma_flush(up);
- fallthrough;
- case UART_IIR_RLSI:
return true;
}
return up->dma->rx_dma(up);
--
2.35.3