From 3b963042b64f5de3c63a1ebcbe2cad6b1597b8b9 Mon Sep 17 00:00:00 2001
From: Muhammad Hamza Farooq <mfarooq@visteon.com>
Date: Fri, 18 Sep 2015 13:08:31 +0200
Subject: [PATCH] serial: sh-sci: Do not terminate DMA engine when race
condition occurs
When DMA packet completion and timer expiry take place at the same time,
do not terminate the DMA engine, leading by submission of new
descriptors, as the DMA communication hasn't necessarily stopped here.
Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/sh-sci.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 84c15152e111..9406fe227bc7 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1296,9 +1296,14 @@ static void rx_timer_fn(unsigned long arg)
}
status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state);
- if (status == DMA_COMPLETE)
+ if (status == DMA_COMPLETE) {
dev_dbg(port->dev, "Cookie %d #%d has already completed\n",
s->active_rx, active);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ /* Let packet complete handler take care of the packet */
+ return;
+ }
/* Handle incomplete DMA receive */
dmaengine_terminate_all(s->chan_rx);
--
2.34.1